DELTAMETHRIN
CASRN: 52918-63-5
For other data, click on the Table of Contents

Human Health Effects:

Evidence for Carcinogenicity:

Evaluation: No data were available from studies in humans. There is inadequate evidence for the carcinogenicity of deltamethrin in experimental animals. Overall evaluation: Deltamethrin is not classifiable as to its carcinogenicity to humans (Group 3).
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. V53 264 (1991)]**PEER REVIEWED**

Human Toxicity Excerpts:

Clinical manifestations of 573 cases of acute pyrethroid poisoning are reviewed. The cases occurred in 14 provinces in China & involved 325 patients exposed to deltamethrin, 196 to fenvalerate, 45 to cypermethrin, & 7 to other pyrethroid compds. Of the 573 cases, 229 were of occupational origin resulting from inappropriate handling of the chemicals such as spraying with higher concn than allowed, sustaining longer exposure durations than recommended, spraying against the wind, clearing stoppage of sprays by mouth & hands, spraying closer than every row of crops, or not wearing personal protective equipment. Those occupationally exposed patients experienced initial burning or itching sensations of the face within a few minutes of exposure or dizziness developing at 4-6 hr after exposure. Half of those occupationally exposed experienced abnormal facial sensations such as burning, itching, or tingling sensation which were exacerbated by sweating & washing with warm water. These symptoms disappeared several hours to 1 day after exposure. Systemic symptoms included dizziness, 60.6%; headache, 44.5%; nausea, 59.7%; anorexia, 45%; & fatigue, 26%. Vomiting occurred in 16% of those who were occupationally exposed. Other symptoms included chest tightness, 13.1%; parasthesia, 11.89%; palpitation, 13.1%; blurred vision, 7%; & incr sweating, 6.7%. Coarse muscular fasciculations developed in large muscles of extremities in the more serious cases. In those suffering from convulsions, seizures could arise up to 30 times/day for the first wk. Blood tests revealed leukocytosis in 15%. Treatment consisted of symptomatic & supportive therapy including gastric lavage. Most recovered in 6 days.
[He F et al; Archives of Toxicology 63 (1): 54-8 (1989)]**PEER REVIEWED**

Among plant workers dermally exposed to technical deltamethrin or its formulations, cutaneous and mucous manifestation were observed. Initial lesions were tenacious painful pruritus, especially observed after exposure to hot water or perspiration, followed by a blotchy local burning sensation with blotchy erythema for about 2 days. Thereafter, slight and regular desquamation, restricted to the contaminated area, occurred. Cutaneous signs were sometimes accompanied by itching of the face (mainly around the mouth) and/or rhinorrhea or lacrymation. ... No long-term or persistent effect, or allergic diseases were reported in 70 workers, who had been exposed from 1977-87 in a deltamethrin-manufacturing and -formulating plant in France.
[WHO; Environmental Health Criteria 97: Deltamethrin p.85 (1990)]**PEER REVIEWED**

A field study was carried out in the United Kingdom with three unprotected operators & one operator wearing hood, gloves, & respirator, all of whom were involved in orchard spraying with deltamethrin according to normal field practice. The exposure time was 3.5 hr. No changes were found in blood cell counts, total protein urea, alkaline phosphates, y-GT & SGOT in blood. Little deltamethrin was found in the respiratory pad & no residues were found in the urine. There was no decr in nerve conduction velocity, but a slight tendency to the opposite reaction. None of the operators experienced facial sensations.
[WHO; Environmental Health Criteria 97: Deltamethrin p.86 (1990)]**PEER REVIEWED**

A health survey was carried out among spraymen exposed to 2.5% deltamethrin emulsifiable concentrate in cotton fields in China. The subjects were exposed to deltamethrin at concn 0.002-24.070 ug/cu m in the air of the respiratory zone & 0.013-0.347 ug/cm sq of skin contact. One half of the 44 sprayers complained of itching & burning sensations on their faces. A few ... red papules also appeared on the face of one them, but no signs of acute deltamethrin poisoning were noticed during physical exam. There were no significant differences in the sodium, potassium, & urea contents of the serum, the sodium, potassium, ATPase, & serotonin contents of whole blood, & the levels of 3-methyl-4-hydroxymandelic acid & 5-hydroxy-indoleacetic acid in the urine between the subjects examined & the controls. Deltamethrin in the urine of spraymen was below the detection limit of 0.10 ug/litre.
[WHO; Environmental Health Criteria 97: Deltamethrin p.87 (1990)]**PEER REVIEWED**

Five healthy volunteers, 16-40 yr of age, were exposed to deltamethrin during 5 days of spraying in a cotton field in India in 1981. A sixth volunteer was engaged in mixing & loading the emulsion during the same period. Spraymen were exposed for 7 hr/day. No one complained about any symptoms. No clinical abnormalities were detected, particularly with respect to neurological exam (muscle power, coordination, tremors, reflexes, & both light & deep sensations). No cardiovascular, respiratory, or abdominal abnormalities were detected, & no skin, mucous membrane, or eye lesions were observed during, & after cessation of exposure.
[WHO; Environmental Health Criteria 97: Deltamethrin p.87 (1990)]**PEER REVIEWED**

Persons exposed to deltamethrin for 7-8 yr in production & formulation were subjected to clinical & hematological exam. Evaluations were conducted at several plants. There were no measurable effects other than transient irritation of cutaneous & mucous membranes, which was without sequelae. Adequate precautionary measures such as the wearing of gloves & face masks, provided protection from exposure.
[WHO; Environmental Health Criteria 97: Deltamethrin p.86 (1990)]**PEER REVIEWED**

A medical survey of agricultural workers involved in the same use & application of emulsified concentrate (EC) & wettable powder (WP) formulations of deltamethrin in Yugoslavia revealed no untoward symptoms of exposure, other than itching & burning of the face, & nasal hypersecretion. Medical exam included chest X-ray, ECG, liver function tests, neurological exam (eye tonometry, Goldman perimetry, dark adaptation ability), kidney function tests, & whole blood & plasma cholinesterase activity. No adverse effects were noted.
[WHO; Environmental Health Criteria 97: Deltamethrin p.86 (1990)]**PEER REVIEWED**

In a department producing an aerosol of the domestic Bulgarian insecticide "Dekazol" containing 0.02, 0.04, or 0.08% deltamethrin, severe subjective complaints of sensory irritation were found because of the high levels of contamination of the workplace air with deltamethrin & also dermal contamination. Skin irritation with conjunctivitis & irritation of the respiratory system were discovered in all 25 workers. Two of them had contact urticaria. Patch testing with 0.03% deltamethrin showed a positive reaction in 5 out of 23 workers tested.
[WHO; Environmental Health Criteria 97: Deltamethrin p.87 (1990)]**PEER REVIEWED**

Three formulations of deltamethrin in petroleum solvent were patch tested on 37 human volunteers (double blind trial against solvent control). A dose of 20 ul of a 1% suspension in water, of a 25 g/litre emulsifiable concentrate was put on the facial skin of each volunteer, with a randomized distribution of control and active dilution. The duration of the irritation was short (from some minutes to 1 hr) and the severity was described as slight by most of the volunteers. No skin damage was reported.
[WHO; Environmental Health Criteria 97: Deltamethrin p.88 (1990)]**PEER REVIEWED**

An agricultural worker as a result of skin contamination with a liquid containing 5g deltamethrin/l ... developed paresthesia in the legs, mouth, & tongue, & diarrhea. Following washing of the skin & admin of antihistamines, he still had tingling sensations in his toes after 24 hr, but was fully recovered after 48 hr.
[WHO; Environmental Health Criteria 97: Deltamethrin p.84 (1990)]**PEER REVIEWED**

Outbreaks of acute deltamethrin & fenvalerate poisoning occurred in cotton growers in China in 1982-84. The farmers handled the pyrethroid insecticides without taking any precautions. Skin sensations occurred in >90% of the exposed workers. After repeated spraying in the cotton fields, the mild cases presented severe headaches, dizziness, fatigue, nausea, & anorexia, with transient changes in the EEG. A severe case developed muscular fasciculation, repetitive discharges in the EMG, & frequent convulsions, which were treated with diazepam & phenobarbital. However, in follow-up studies, all workers were found to have made complete recovery, & the prognosis of acute pyrethroid poisoning was found to be good.
[WHO; Environmental Health Criteria 97: Deltamethrin p.85 (1990)]**PEER REVIEWED**

Attempted suicide by a 23-yr-old man, was reported. After oral absorption of 70 cc of a 2.5% emulsified concentrate (EC) formulation (1.75 g pure deltamethrin), there were no neurological signs in this patient. Digestive & hepatic signs occurred, probably due to absorption of the solvent, since determination of xylene in plasma was positive. The patient was treated with hemodialysis, phenobarbital, lidocaine, & provoked alkaline diuresis. Recovery followed within 48 hr.
[WHO; Environmental Health Criteria 97: Deltamethrin p.84 (1990)]**PEER REVIEWED**

A 13-year-old girl who ingested voluntarily 200 ml of a 2.5% emulsified concentrate (EC) formulation (5 grams of deltamethrin), ... lost consciousness and developed generalized muscle cramps, myosis, and tachycardia. Treatment in hospital was as follows: gastric lavage, ... PAM; ... atropine; ... sodium nitrite, ...sodium thiosulfate; and, lastly, high doses of diazepam. She completely recovered in 48 hr.
[WHO; Environmental Health Criteria 97: Deltamethrin p.84 (1990)]**PEER REVIEWED**

One notable form of toxicity associated with synthetic pyrethroids has been a cutaneous paresthesia observed in workers spraying esters containing alpha-cyano substituent (/eg/ deltamethrin ...). The paresthesia developed several hr following exposure, being described as a stinging or burning sensation on the skin which, in some cases, progressed to a tingling & numbness, the effects lasting some 12-18 hr.
[Amdur, M.O., J. Doull, C.D. Klaasen (eds). Casarett and Doull's Toxicology. 4th ed. New York, NY: Pergamon Press, 1991. 594]**PEER REVIEWED**

Workers exposed to deltamethrin during its manufacture over 7-8 yr experienced transient cutaneous & mucous membrane irritation which could be prevented by use of gloves & face masks, but no other ill effects were seen.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 596]**PEER REVIEWED**

Workers handling deltamethrin concentrates, especially in aromatic solvents, without adequate protection of the facial skin experienced more severe irritation. This involved an initial painful pruritis & a blotchy erythema & burning sensation, which persisted for several days.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 596]**PEER REVIEWED**

An epidemiological study of the prevalence of acute pyrethroid poisoning in cotton farmers was conducted in a cohort of 3113 cotton farmers (2230 males) from 8 villages in Gaocheng County, People's Republic of China. Subjects were interviewed by questionnaire to obtain information on demographic characteristics, exposure to pyrethroids or other pesticides, symptoms of exposure, medical history, & use of protective gear. 38 male applicators were selected for environmental & biological monitoring over a 72 hr period starting before & continuing to 1 day after spraying. Environmental monitoring was performed by measuring breathing zone & dermal exposures. Biological monitoring was performed by analyzing urine samples for pyrethroids. The subjects sprayed deltamethrin & fenvalerate. Respiratory exposures of deltamethrin & fenvalerate ranged up to 0.53 & 1.19 ug/hr, respectively. Dermal exposures to deltamethrin & fenvalerate ranged from 0.02 to 1.56 & 1.25 to 6.42 mg/hr, respectively. Urinary excretion of deltamethrin & fenvalerate ranged up to 0.4 & 0.33 ug/liter, respectively. A total of 834 subjects (26.9%) developed symptoms such as abnormal facial sensations, dizziness, headache, fatigue, nausea, or anorexia after spraying pure pyrethroids or mixtures of pyrethroids & organophosphates. 10 subjects who developed significant systemic symptoms, listlessness & muscular fasciculations, were diagnosed as having acute pyrethroid poisoning. A total of 2131 subjects had been exposed to pyrethroids previously. Of these, 696 reported symptoms in this study. A total of 2173 subjects were not aware of the toxicity of pyrethroids. Use of protective equipment was negligible. Contamination of the shoes & trousers occurred in 93.1 & 65% of the subjects, respectively. It was concluded that 26.9% of the subjects have been clinically affected by exposure to pyrethroids, with dermal contamination as a major route.
[Chen S et al; Br J Ind Med 48 (2): 77-81 (1991)]**PEER REVIEWED**

Contact allergy from pyrethroids ... has not been observed. /Pyrethroids/
[Zenz, C., O.B. Dickerson, E.P. Horvath. Occupational Medicine. 3rd ed. St. Louis, MO., 1994 108]**PEER REVIEWED**

The allergenic properties of pyrethroids /with early pyrethrum preparations/ are marked in comparison with other pesticides. Many cases of contact dermatitis and respiratory allergy have been reported. Persons sensitive to ragweed pollen are particularly prone to such reactions. Preparations containing synthetic pyrethroids are less likely to cause allergic reactions than are the preparations made from pyrethrum powder. /Pyrethroids/
[Hardman, J.G., L.E. Limbird, P.B. Molinoff, R.W. Ruddon, A.G. Goodman (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 9th ed. New York, NY: McGraw-Hill, 1996. 1687]**PEER REVIEWED**

Some pyrethroid (eg, deltamethrin, fenvalerate, cyhalothrin, lambda-cyhalothrin, flucythrinate, & cypermethrin) may cause a transient itching &/or burning sensation in exposed human skin. /Synthetic pyrethroids/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.13 (1990)]**PEER REVIEWED**

The clinical manifestations of inhalation exposure to pyrethrins can be local or systemic. Localized reactors confined to the upper respiratory tract include rhinitis, sneezing, scratchy throat, oral mucosal edema, and even laryngeal mucosal edema. Localized reaction of the lower respiratory tract include cough, shortness of breath, wheezing, and chest pain. An asthmalike reaction occurs with acute exposures in sensitized patients. Hypersensitivity pneumonitis characterized by chest pain, cough, dyspnea, & bronchospasm may occur in an individual chronically exposed. /Pyrethrum and synthetic pyrethroids/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1626]**PEER REVIEWED**

Skin, Eye and Respiratory Irritations:

The chief effect from exposure ... is skin rash particularly on moist areas of the skin. ... May irritate the eyes.
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 1]**PEER REVIEWED**

Medical Surveillance:

Initial medical screening: Employees should be screened for history of certain medical conditions ... which might place the employee at increased risk from /pyrethroid/ exposure. Chronic respiratory disease: In persons with chronic respiratory disease, especially asthma, the inhalation of /pyrethroids/ might cause exacerbation of symptoms due to its sensitizing properities. Skin disease: /Pyrethroids/ can cause dermatitis which may be allergic in nature. Persons with pre-existing skin disorders may be more susceptible to the effects of this agent. Any employee developing the above-listed conditions should be referred for further medical examination. /Pyrethrum/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 1]**PEER REVIEWED**

Populations at Special Risk:

Chronic respiratory disease: In persons with chronic respiratory disease, especially asthma, the inhalation of /pyrethroids/ might cause exacerbation of symptoms due to its sensitizing properities. Skin disease: /Pyrethroids/ can cause dermatitis which may be allergic in nature. Persons with pre-existing skin disorders may be more susceptible to the effects of this agent. ... /Pyrethroids/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 1]**PEER REVIEWED**

Probable Routes of Human Exposure:

Dermal exposure of deltamethrin to a pilot applying the insecticide while flying an ultra-light aircraft was 10.8 ug/hr(1); a ground-based flagman on duty during the aerial spraying received a dermal exposure of 25 ug/hr(1); dermal exposure to workers manually spraying deltamethrin was 2.8-42.2 mg/hr(1); the 1000-fold exposure difference between hand-held applicators and aerial applicators was due, in part, to work practices of the workers(1). Inhalation exposure of workers involved in spray applications of deltamethrin in greenhouses was measured as 5.2 ug/cu m at the time of spraying and 0.008 ug/cu m 30 min after spraying(2); dermal exposures (chest, back, arms, forearms, hands, legs) ranged from 0.21 to 10.5 ug/100 cu cm(2). Workers packaging deltamethrin in a small importing factory in China were reported to have been exposed to airborne levels of 0.2-1.2 ug/cu m, with resulting skin contact(3). Air concns of deltamethrin at the breathing zone of workers spraying deltamethrin insecticide on cotton was 0.02-0.11 ug/cu m(4); dermal exposure ranged from 0.14 to 1.48 ug/cu cm on forearms, hands, legs and feet(4). Occupational exposure to deltamethrin may occur through inhalation of dust particles and dermal contact with this compound at workplaces where deltamethrin is produced or used. Monitoring data indicate that the general population may be exposed to deltamethrin via inhalation of ambient air, ingestion of food and dermal contact with this compound(SRC).
[(1) Yoshida K et al; J Environ Sci Health B25: 151-67 (1990) (2) Mestres R et al; Bull Environ Contam Toxicol 35: 750-6 (1985) (3) IARC; IARC Monographs on the Evaluation of Carcinogen Risks to Humans. Lyon, France: World Health Organization 53: 251-66 (1991) (4) Zhang Z et al; Brit J Industr Med 48: 82-6 (1991)]**PEER REVIEWED**

Body Burden:

Urine concns of deltamethrin of workers spraying deltamethrin insecticide on cotton was 0.01-1.79 ug/collection interval (3-12 hr) for a period up to 72 hr after spraying(1).
[(1) Zhang Z et al; Brit J Industr Med 48: 82-6 (1991)]**PEER REVIEWED**

Emergency Medical Treatment:

Emergency Medical Treatment:

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The following Overview, *** PYRETHRINS ***, is relevant for this HSDB record chemical.

Life Support:
  o   This overview assumes that basic life support measures
      have been instituted.                           
Clinical Effects:
  SUMMARY OF EXPOSURE
   0.2.1.1 ACUTE EXPOSURE
     o   The mammalian toxicity of natural pyrethrins is
         generally low.  Very young children are perhaps more
         susceptible to poisoning because they may not hydrolyze
         the pyrethrum esters efficiently.  In humans, allergic
         reactions are the main toxic manifestations of
         pyrethrin exposure.
      1.  Pyrethrum and the pyrethrins produce typical type I
          motor symptoms in mammals.  Severe type I poisoning
          may include the following signs in humans:
           Severe fine tremor
           Marked reflex hyperexcitability
           Sympathetic activation
           Paresthesia (dermal exposure)
     o   DERMAL - These compounds are not primary irritants.
         The chief effect, however, from exposure is dermatitis.
         The usual lesion is a mild erythematous dermatitis with
         vesicles, papules in moist areas, and intense pruritus;
         a bulbous dermatitis may also occur.  Pyrethrins can
         cause allergic dermatitis and systemic allergic
         reactions.
     o   INHALATION is the major route of exposure, with airway
         irritation as the primary toxic effect.  Following
         inhalation, a stuffy, runny nose and scratchy throat
         are common.  Hypersensitivity reactions including
         wheezing, sneezing, shortness of breath and
         bronchospasm may be noted.
     o   OCULAR - Eye exposures may result in mild to severe
         corneal damage that generally  resolves with
         conservative care.
     o   Piperonyl butoxide and other compounds are often added
         to pyrethrin insecticides as synergists and may
         contribute to toxicity.
     o   Synthetic pyrethroids, which are related to pyrethrins,
         are covered in a separate management.
  HEENT
   0.2.4.1 ACUTE EXPOSURE
     o   A stuffy, runny nose and scratchy throat following
         inhalational exposure may be noted.
     o   Eye exposures may result in mild to severe corneal
         damage, decreased visual acuity and periorbital edema.
  CARDIOVASCULAR
   0.2.5.1 ACUTE EXPOSURE
     o   Hypotension and tachycardia, associated with
         anaphylaxis, may occur.
  RESPIRATORY
   0.2.6.1 ACUTE EXPOSURE
     o   Hypersensitivity reactions characterized by
         pneumonitis, cough, dyspnea, wheezing, chest pain, and
         bronchospasm may occur.  Rare cases of respiratory
         failure and cardiopulmonary arrest have been reported.
  NEUROLOGIC
   0.2.7.1 ACUTE EXPOSURE
     o   Paresthesias, headaches, and dizziness are common.
         Massive exposure may result in hyperexcitability and
         seizures, but this is rare.
  GASTROINTESTINAL
   0.2.8.1 ACUTE EXPOSURE
     o   Nausea, vomiting and abdominal pain commonly occur and
         develop within 10 to 60 minutes following ingestion.
  DERMATOLOGIC
   0.2.14.1 ACUTE EXPOSURE
     o   Irritant and contact dermatitis may develop.  Erythema
         which mimics sunburn has also been noted after
         prolonged repeated exposure.
  ENDOCRINE
   0.2.16.1 ACUTE EXPOSURE
     o   Type I motor symptoms following severe poisoning may
         result in sympathetic activation.
  IMMUNOLOGIC
   0.2.19.1 ACUTE EXPOSURE
     o   Sudden bronchospasm, swelling of oral and laryngeal
         mucous membranes, and anaphylactoid reactions have been
         reported after pyrethrum inhalation.  Hypersensitivity
         pneumonitis characterized by cough, shortness of
         breath, chest pain, and bronchospasm may be noted.
  GENOTOXICITY
    o   Pyrethrum is not mutagenic in bacterial reversion tests
        (Ray, 1991).                    
Laboratory:
  o   Pyrethrin plasma levels are not clinically useful or
      readily available.
  o   Monitor for allergic responses such as asthma or contact
      dermatitis.               
Treatment Overview:
  ORAL EXPOSURE
    o   There is no specific antidote for pyrethrin poisoning.
        Treatment is symptomatic and supportive and includes
        monitoring for the development of hypersensitivity
        reactions with respiratory distress.  Provide adequate
        airway management when needed.  Gastric decontamination
        is usually not required unless the pyrethrin product is
        combined with a hydrocarbon.
    o   ALLERGIC REACTION:  MILD:  antihistamines with or
        without epinephrine.   SEVERE:  oxygen, aggressive
        airway management, antihistamines, epinephrine  (ADULT:
        0.3 to 0.5 mL of a 1:1000 solution subcutaneously;
        CHILD:  0.01  mL/kg; may repeat in 20 to 30 min),
        corticosteroids, ECG monitoring, and IV fluids.
  INHALATION EXPOSURE
    o   INHALATION:  Move patient to fresh air.  Monitor for
        respiratory distress.  If cough or difficulty breathing
        develops, evaluate for respiratory tract irritation,
        bronchitis, or pneumonitis.  Administer oxygen and
        assist ventilation as required.  Treat bronchospasm with
        beta2  agonist and corticosteroid aerosols.
  EYE EXPOSURE
    o   DECONTAMINATION:  Irrigate exposed eyes with copious
        amounts of tepid water for at least 15 minutes.  If
        irritation, pain, swelling, lacrimation, or photophobia
        persist, the patient should be seen in a health care
        facility.
  DERMAL EXPOSURE
    o   DECONTAMINATION:  Remove contaminated clothing and wash
        exposed  area thoroughly with soap and water.  A
        physician may need to  examine the area if irritation or
        pain persists.
    o   Vitamin E topical application is highly effective in
        relieving paresthesias.                
Range of Toxicity:
  o   The minimal lethal dose of pyrethrum is not established,
      but is probably  in the range of 10 to 100 grams.
  o   Hypersensitivity reactions may be noted, especially
      following a chronic dermal or inhalation exposure.
      Patients with underlying asthma may be  predisposed to
      severe bronchospastic reactions after exposure.


[Rumack BH: POISINDEX(R) Information System. Micromedex, Inc., Englewood, CO, 2001; CCIS Volume 110, edition exp November, 2001. Hall AH & Rumack BH (Eds):TOMES(R) Information System. Micromedex, Inc., Englewood, CO, 2001; CCIS Volume 110, edition exp November, 2001.] **PEER REVIEWED**

Antidote and Emergency Treatment:

Treatment is supportive, and most casual exposures require only decontamination. Topical vitamin E may ameliorate the paresthesias that accompany contact with synthetic pyrethroids containing an alpha-cyano group (e.g., fenvalerate, cypermethrin, flucythrinate). /Synthetic pyrethroids/
[Ellenhorn, M.J. and D.G. Barceloux. Medical Toxicology - Diagnosis and Treatment of Human Poisoning. New York, NY: Elsevier Science Publishing Co., Inc. 1988. 1081]**PEER REVIEWED**

The additives (e.g. petroleum distillate), when present, represent a greater toxic threat to the patient than the active ingredient itself. ... Emesis should not be induced when petroleum distillate additives are present unless the product ingested is estimated to contain a near lethal dose (1 g/kg) of pyrethrum or pyrethrins. The alert person with an intact gag reflex & a sublethal pyrethrum ingestion without other toxic constituents may have emesis induced by ipecac, followed by a saline cathartic & slurry of activated charcoal. ... Pulmonary & allergic sequelae are treated symptomatically with airway maintenance, oxygen, & ventilatory assistance as required. Standard drugs and management protocols may be used for treatment of bronchospasm & anaphylaxis. Seizures are treated with diazepam. /Pyrethrum and synthetic pyrethroids/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1627]**PEER REVIEWED**

As in animals, the "seizures" were poorly controlled by anesthetics, phenytoin, diazepam or chlorpromazine whilst atropine was effective against the hypersalivation and pulmonary edema.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 595]**PEER REVIEWED**

Skin decontamination. Wash skin promptly with soap and water ... . If irritant or paresthetic effects occur, obtain treatment by a physician. Because volatilization of pyrethroids apparently accounts for paresthesia affecting the face, strenuous measures should be taken (ventilation, protective face mask and hood) to avoid vapor contact with the face and eyes. Vitamin E oil preparations (dL-alpha tocopheryl acetate) are uniquely effective in preventing and stopping the paresthetic reaction. They are safe for application to the skin under field conditions. Corn oil is somewhat effective, but possible side effects with continuing use make it less suitable. Vaseline is less effective than corn oil. Zinc oxide actually worsens the reaction. /Pyrethroids/
[U.S. Environmental Protection Agency/Office of Prevention, Pesticides, and Toxic Substances. Reigart, J.R., Roberts, J.R. Recognition and Management ofPesticide Poisonings. 5th ed. 1999. EPA Document No. EPA 735-R-98-003, and available in electronic format at: http://www.epa.gov/pesticides/safety/healthcare 88]**PEER REVIEWED**

Eye contamination. Some pyrethroid compounds can be very corrosive to the eyes. Extraordinary measures should be taken to avoid eye contamination. the eye should be treated immediately by prolonged flushing of the eye with copious amounts of clean water or saline. If irritation persists, obtain professional ophthalmologic care. /Pyrethroids/
[U.S. Environmental Protection Agency/Office of Prevention, Pesticides, and Toxic Substances. Reigart, J.R., Roberts, J.R. Recognition and Management ofPesticide Poisonings. 5th ed. 1999. EPA Document No. EPA 735-R-98-003, and available in electronic format at: http://www.epa.gov/pesticides/safety/healthcare 88]**PEER REVIEWED**

Other treatments. Several drugs are effective in relieving the pyrethroid neurotoxic manifestations observed in deliberately poisoned laboratory animals, but none has been tested in human poisonings. Therefore, neither efficacy nor safety under these circumstances is known. Furthermore, moderate neurotoxic symptoms and signs are likely to resolve spontaneously if they do occur. /Pyrethroids/
[U.S. Environmental Protection Agency/Office of Prevention, Pesticides, and Toxic Substances. Reigart, J.R., Roberts, J.R. Recognition and Management ofPesticide Poisonings. 5th ed. 1999. EPA Document No. EPA 735-R-98-003, and available in electronic format at: http://www.epa.gov/pesticides/safety/healthcare 89]**PEER REVIEWED**

Animal Toxicity Studies:

Evidence for Carcinogenicity:

Evaluation: No data were available from studies in humans. There is inadequate evidence for the carcinogenicity of deltamethrin in experimental animals. Overall evaluation: Deltamethrin is not classifiable as to its carcinogenicity to humans (Group 3).
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. V53 264 (1991)]**PEER REVIEWED**

 

Non-Human Toxicity Excerpts:

The type II pyrethroids /including deltamethrin/ produce a complex poisoning syndrome & act on a wide range of tissues. They give sodium tail currents with relatively long time constants, which may be the reason for their ability to act on the whole range of excitable tissues. Type II poisoning in rats involves progressive development of nosing & exaggerated jaw opening similar to that seen in response to an irritant placed on the tongue, salivation which may be profuse, incr extensor tone in the hind limbs causing a rolling gait, incoordination progressing to a very coarse tremor, choreoform movements of the limbs & tail often precipitated by sensory stimuli, generalized choreoathetosis (writhing spasms), tonic seizures, apnea, & death. At lower doses more subtle repetitive behavior is seen. In dogs, similar symptoms are seen but salivation & upper airway hypersecretion and gastrointestineal symptoms are more prominent.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 590]**PEER REVIEWED**

Pyrethroids are potent synthetic insecticides which have been increasingly employed in recent years. Such compounds have been shown to bind covalently to hepatic proteins. Covalent binding is often associated with toxic effects. Possible cytotoxic, cytogenotoxic and allergenic effects could be due to covalent binding of these compounds and/or their metabolites to endogenous macromolecules. In the present paper we examined possible cytotoxic effects of certain pyrethroids on human lyphocytes and L 1210 lymphoblastoid mouse cells, cytogenotoxic effects with micronuclei test and allergenic effects with Magnusson and mast cell degranulation tests. Under our experimental conditions, the tested compounds showed neither acute cytotoxic nor cytogenotoxic effects, though, cismethrin presented slight antimitotic effects statistically different to those with the control. Slight allergenic character of cismethrin, bioresmethrin and deltamethrin was revealed by Magnusson and mast cell degranulation tests.
[Hoellinger H et al; Drug Chem Toxicol 10 (3-4): 291-310 (1987)]**PEER REVIEWED**

Non-phytotoxic
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

Deltamethrin dissolved in maize oil was administered in the diet to 64 beagle dogs (8 of each sex per group) at levels of 0, 1, 10, and 40 mg/kg for 24 months. This corresponds to 0, 0.025, 0.25, and 1 mg/kg body weight, respectively. Individual body weights and food consumption values were determined weekly. Ophthalmoscopic, hematological, biochemical, and urinalysis examinations were conducted during the pretest period at 6, 12, 18, and 24 months of the study. Neurological examinations were conducted at approximately 1 year and before termination. No signs of overt toxicity were observed in any of the dogs. Body weight and food consumption values were similar for control and treated dogs. No compound-related effects were observed during the ophthalmoscopic and physical examinations. Although there were some random statistically significant differences between the control and other dose groups in the hematological and biochemical tests, physiologically significant changes were not observed at any interval in the study. Two treated and two control animals died during the study. No compound-related gross or microscopic changes were observed in the surviving dogs that were sacrificed and necropsied. Inflammatory, degenerative, and proliferative changes described were spontaneous in nature, or related to the estrous phase of the menstrual cycle, and unrelated to compound administration. On the basis of this study, it has been concluded that the no-observed-effect level is 40 mg/kg diet (equivalent to 1 mg/kg body weight per day).
[WHO; Environmental Health Criteria 97: Deltamethrin p.72 (1990)]**PEER REVIEWED**

DNA repair tests in Escherichia coli were conducted at dose levels of 1250, 2500, or 5000 ug deltamethrin/ml. Deltamethrin was dissolved in dimethyl sulfoxide (DMSO) and 0.1 ml of the solution was spread on a plate. Growth inhibition was compared between DNA repair deficient mutants (p3478 and CM611) and wild types (W3110 and WP2). Partial precipitation of deltamethrin from the soluton occurred when it came into contact with the aqueous bacterial growth medium. Deltamethrin did not have any damaging effects on DNA.
[WHO; Environmental Health Criteria 97: Deltamethrin p.72 (1990)]**PEER REVIEWED**

Deltamethrin was examined for its mutagenic potential in the Ames test with 5 strains of Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA98, and TA100) and doses of 2, 10, 50, 200, 500, 1000, or 5000 ug/plate, with and without S-9 mix (metabolic enzyme system). It was dissolved in DMSO and precipitated out of solution at concentrations of 200 ug/plate or more. Deltamethrin did not have any effect on the mutation rate in any of the strains at any of the concentrations tested. ... A similar Ames test was carried out at 0.2, 2, 20, 200, or 500 ug deltamethrin/plate with microsome enzymes. The compounds did not influence the number of revertants of the 5 strains (same as above) of Salmonella typhimurium. Again, deltamethrin was dissolved in DMSO and precipated out of solution at 200 ug/plate or more.
[WHO; Environmental Health Criteria 97: Deltamethrin p.73 (1990)]**PEER REVIEWED**

Deltamethrin was found not to be mutagenic in V79 Chinese hamster cells, in the presence or absence of hepatocytes.
[WHO; Environmental Health Criteria 97: Deltamethrin p.74 (1990)]**PEER REVIEWED**

An in vivo cytogenetic test was conducted on mice (3 males and 3 females per group). Mice were treated orally with deltamethrin in sesame oil for 2 consecutive days at 5 or 10 mg/kg body weight. The incidence of chromosomal aberrations in bone marrow cells or micronuclei in the polychromatic erythrocytes of treated groups was, however, comparable to that of the control groups. No positive controls were tested.
[WHO; Environmental Health Criteria 97: Deltamethrin p.74 (1990)]**PEER REVIEWED**

Deltamethrin was applied orally, once, at 15 mg/kg body weight to Swiss mice. A time-related effect on the chromosomes in bone marrow cells was observed by killing 2 animals every 3 hr during 24 hr. The report stated that incidences of chromatid aberrations were low and that there were no consistent time-related trends in the distribution of the aberrations. However, the time-related trend of aberrations was not reported. Again, no positive controls were tested.
[WHO; Environmental Health Criteria 97: Deltamethrin p.74 (1990)]**PEER REVIEWED**

In a micronucleus test, a single dose of deltamethrin in corn oil was administered orally at 16 mg/kg body weight to Swiss CD-1 mice (5 of each sex per group). No mutagenic activity was observed with deltamethrin, whereas the positive controls, triethylenemelamine and dimethylbenzanthracene, both induce positive responses.
[WHO; Environmental Health Criteria 97: Deltamethrin p.75 (1990)]**PEER REVIEWED**

A dominant-lethal assay with deltamethrin was performed. Groups of 9-13 male mice were dosed orally at 3 mg/kg body weight in sesame oil for 7 days or at a single dose of 6 or 15 mg/kg body weight in sesame oil, and mated with 6-18 non-treated females. There were no effects on the rates of pre- and post- implantation losses, while the positive control, triethylene triphosphoramide (10 mg/kg body weight), reduced pregnancies in the second and third weeks after treatment and increased embryonic losses.
[WHO; Environmental Health Criteria 97: Deltamethrin p.74 (1990)]**PEER REVIEWED**

Deltamethrin in olive oil was administered orally to female Swiss mice at single or repeated (5 times at daily intervals) doses of 1.36, 3.4, or 6.8 mg/kg per day. Bone marrow smears were prepared 6, 24, or 48 hr after treatment. No mutagenic activity was observed with deltamethrin, whereas the positive control, cyclophosphamide, induced a positive response.
[WHO; Environmental Health Criteria 97: Deltamethrin p.75 (1990)]**PEER REVIEWED**

Deltamethrin was dissolved in corn oil and administered by gastric intubation at doses of 0, 3.0, 6.0, or 12.0 mg/kg body weight on days 7-16 of gestation to groups of CD-1 mice. Mice were sacrificed on day 18 of gestation. There was a dose-related (P <0.001) reduction in maternal weight gain during pregnancy and high-dose females gained 58% less weight than the controls. There was no dose-related mortality but dams in the high- and mid-dose groups became convulsive after dosing. Treatment did not affect the number of implantation sites, fetal mortality, fetal weights, or the number of sternal and caudal ossification centers. A significant (p <0.01) dose-related increase in the occurrence of supernumerary ribs was observed. No other dose-related skeletal or visceral anomalies were observed.
[WHO; Environmental Health Criteria 97: Deltamethrin p.75 (1990)]**PEER REVIEWED**

Pregnant female Swiss CD-1 SPF mice (24 per group) were given deltamethrin dissolved in sesame oil by oral intubation at dose-levels of 0, 0.1, 1, or 10 mg/kg body weight per day on days 6-17 of pregnancy. The animals were necropsied on day 18 of pregnancy. The numbers of implantation sites fetal losses, and viable fetuses were not affected by treatment. There was a dose-related decrease in mean fetal weight. Apart from delayed ossification at all dose levels, skeletal examination revealed no abnormalities. A teratogenic effect was not observed.
[WHO; Environmental Health Criteria 97: Deltamethrin p.76 (1990)]**PEER REVIEWED**

In a complementary teratology study, pregnant female Swiss CD-1 mice were given deltamethrin dissolved in sesame oil by oral intubation at 0, 0.1, 1, or 10 mg/kg body weight per day from day 6 to day 17 of gestation. Females were either sacrificed on day 18 of gestation or allowed to litter for subsequent examination of pups on days 1 or 21 of lactation. The compound caused a moderate and transient retardation of development of the fetus at the 1 and 10 mg/kg body weight dose rate, but these effects were not observed on days 1 or 21 post-partum. There were no teratogenic effects related to treatment.
[WHO; Environmental Health Criteria 97: Deltamethrin p.76 (1990)]**PEER REVIEWED**

Pregnant female Sprague-Dawley rats (24 per group) received 0, 0.1, 1, or 10 mg deltamethrin/kg body weight per day oral intubation on days 6-18 of pregnancy. Apart from 12 females in the control and 10 mg/kg groups, which were allowed to deliver, the dams were sacrificed and examined on day 21. There were no effects on reproduction or on the teratogenic parameters examined, except for slightly delayed ossification at the highest dose level.
[WHO; Environmental Health Criteria 97: Deltamethrin p.76 (1990)]**PEER REVIEWED**

Deltamethrin was dissolved in corn oil and administered by gastric intubation at doses of 0, 1.25, 2.5, or 5.0 mg/kg body weight on days 7-20 of gestation. Rats were sacrificed on day 21 of gestation. There was a dose related reduction (P <0.01) in maternal weight gain during pregnancy, and dams in the highdose group gained only 80% of the control value. Treatment did not affect the number of implantation sites, fetal mortality, fetal weight, or the number of sternal and caudal ossification centers.
[WHO; Environmental Health Criteria 97: Deltamethrin p.76 (1990)]**PEER REVIEWED**

Groups of 15 pregnant New Zealand White rabbits received deltamethrin dissolved in sesame oil at levels of 0, 1, 4, or 16 mg/kg body weight per day during days 6-19 of pregnancy. Examination was carried out on day 28 of gestation. The mean fetal loss was not dose-related. The mean fetal weight in the highest-dose group was decreased. Some malformations (hydrocephaly, exencephaly, and thoracogastroschisis) were observed in 2 fetuses of animals at the highest dose level. In a supplementary study, pregnant rabbits were similarly dosed with 16 mg/kg body weight per day; one fetus with spina bifida and shortened tail was detected among 69 apparently normal fetuses. Malformations were within the normal limits of the strain used and were not considered to be related to the treatment, despite the occurrence at the highest dose level only.
[WHO; Environmental Health Criteria 97: Deltamethrin p.77 (1990)]**PEER REVIEWED**

Adult hens (10per group) were gavaged with a single dose of 0, 500, 1250, or 5000 mg deltamethrin/kg body weight suspended in corn oil or 0 or 100 mg/kg body weight dissolved in sesame oil. During 21 days, observations were made on mortality, health, neurotoxic signs, and body weight. Deltamethrin did not induce any clinical, macroscopic, or histological signs of delayed neurotoxicity.
[WHO; Environmental Health Criteria 97: Deltamethrin p.78 (1990)]**PEER REVIEWED**

Groups of 5 male and l5 female Wistar rats were administered 25 mg deltamethrin/kg body weight in 10 mg corn oil/kg body weight. A tilting plane test was performed every second day from day 4 to day 16 of the study. Two male rats died at 25 mg/kg. No effect was found on the slip-angle.
[WHO; Environmental Health Criteria 97: Deltamethrin p.78 (1990)]**PEER REVIEWED**

The effects of deltamethrin were studied in a rat performance test that arranged for milk delivery after every fortieth lever press. Deltamethrin (1-8 mg/kg body weight, given orally, 2 hr before the test) produced both dose-related increases in pause duration and decreases in response rate. Deltamethrin was also studied using a conditional flavor-aversion test. Deltamethrin treated, trained rats displayed an aversion to saccharin that was greatest at 2 mg/kg.
[WHO; Environmental Health Criteria 97: Deltamethrin p.79 (1990)]**PEER REVIEWED**

To better characterize the behavioral toxicity of pyrethroid insecticides, comparisons were made of the effects of cismethrin and deltamethrin exposure and motor activity and the acoustic startle response in Long-Evans rats. Acute dose-effect acute time-course, and 30-day repeated-exposure determinations of 1-hr motor activity were made using figure-eight mazes. The acoustic startle response was measured to a 13-kHz, 120-dB(A), 40-millisecond tone at each of 3 background white noise levels (50, 65, and 80 dB). Deltamethrin (0,2,4,6, or 8 mg/kg body weight) or cismethrin (0,6,12,18, or 24 mg/kg) were administered orally in 0.2 ml/kg corn oil. Cismethrin and deltamethrin produced similar dose-dependent decreases in motor activity. The time course of onset and recovery for this decreased activity was rapid (1-4 hr). No cumulative effects on motor activity of 30-day exposure to 2 mg deltamethrin/kg per day or 6 mg cismethrin/kg per day were found. The effects of cismethrin and deltamethrin on the acoustic startle response were dissimilar: deltamethrin produced a dose-dependent decrease in amplitude and an increase in latency, and cismethrin produced an increase in amplitude and no change in latency. The differential effects of cismethrin (Type I pyrethroids) and deltamethrin (Type II pyrethroids) on the acoustic startle response may be related to the contrasting effects previously shown with neurophysiological and/or neurochemical techniques.
[WHO; Environmental Health Criteria 97: Deltamethrin p.79 (1990)]**PEER REVIEWED**

The neurological effects of the 4 synthetic pyrethroids, resmethrin, permethrin, cypermethrin, and deltamethrin, have been investigated in the rat to establish whether there is a correlation between the clinical-functional status of the animal and peripheral nerve damage, as measured biochemically. Neuromuscular dysfunction was assessed by means of inclined plane test and peripheral nerve damage by reference to beta-glucuronidase and beta-galactosidase activity increases in nerve tissue homogenates from treated and control animals. A transient functional impairment was found in animals treated with any one of the 4 pyrethroids tested and in all cases this was greatest at the end of the 7 day dosing regimen (deltamethrin doses of 5-20 mg/kg per day in arachis oil). Significant increases in beta-glucuronidase and beta-galactosidase activities were found 3-4 weeks after the start of dosing, in the distal portion of the sciatic/posterior tibial nerves from permethrin-, cypermethin-, and deltamethrin-treated animals, but no changes were found in resmethrin-treated animals. It is concluded therefore that there is no direct correlation between the time-course of the neuromuscular dysfunction and the neurobiochemical changes. This suggests that these pyrethroids have at least two distinct actions-a short-term pharmacological effect at near-lethal dose levels and a more long-term neurotoxic effect that results in sparse axonal nerve damage.
[WHO; Environmental Health Criteria 97: Deltamethrin p.79 (1990)]**PEER REVIEWED**

When rats were dosed orally with a single dose of 1/2 LD50 or 3 daily doses of 1/5 LD50 deltamethrin, the activities of transferrin and ceruloplasmin in plasma, 20 hr after dosing, were unchanged. After the single dose, microsomal mono-oxygenase activity was increased by 87%, and after the 3 doses, it was increased by 290%.
[WHO; Environmental Health Criteria 97: Deltamethrin p.81 (1990)]**PEER REVIEWED**

Non-irritating to skin, mild eye irritant (rabbits).
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

In 2-year feeding trials, no effect level for rats was 2.1 mg/kg diet, for mice 12 mg/kg diet, and for dogs 1 mg/kg bw. Non-mutagenic and non-teratogenic (mice, rats, rabbits).
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

Rats & dogs given oral doses of 10 mg/kg/day for 13 wk showed some motor symptoms but no fatalities & showed no pathological changes. The dogs showed diarrhea, vomiting, & depression of the gag & patellar reflexes & hind limb placing reaction in addition to the typical type II motor symptoms.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 595]**PEER REVIEWED**

Rats given 15 daily oral doses of 10mg/kg (LD50) showed severe motor symptoms, but a full neuropathological exam of the CNS showed no pathological changes.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 595]**PEER REVIEWED**

Deltametrin has no teratogenic or mutagenic activity.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 595]**PEER REVIEWED**

Signs of acute intoxication in rats and mice included salivation, ataxia and choreoathetotic movements.
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. V53 260 (1991)]**PEER REVIEWED**

Deltamethrin has been tested for carcinogenicity in one study in C57Bl/6 mice and BD-VI rats that were given up to 8 mg/kg orally, respectively. Deltamethrin was not carcinogenic to mice. Deltamethrin caused unspecified thyroid adenomas in male rats given 3 mg/kg and female rats given 6 mg/kg. ... Deltamethrin demonstrated high acute toxicity in laboratory animals, median lethal doses of 30 to 50 mg/kg being measured. Deltamethrin has demonstrated clastogenicity in in vivo mouse bone marrow and sperm assays. Deltamethrin was not mutagenic in bacterial assays, but induced chromosome aberrations in plant cells.
[Anonymous; IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 53: Occupational Exposures in Insecticide Application, and Some Pesticides, p.251-266 (1991)]**PEER REVIEWED**

For teratogenicity, decamethrin (1.0, 2.5 and 5.0 mg/kg) was given orally to female albino rats daily from day 6 through 15 of gestation. The compound produced a dose-related mortality of the dam. At the highest dose level (5.0 mg/kg), maternal weight gain and gravid uterine fetal weights were significantly reduced. The number of implants resorption frequency, number of live fetuses and sex ratio were unaffected at any of the dose levels used in the study. A few incidences in minor malformation(s) like focal subcutaneous haemorrhages and retarded growth were observed in both the treated and control groups. The only skeletal variation was bilateral wavy ribs in one of the fetuses of dams. There were quite low incidences of microphthalmia and hypoplastic kidney but these variations were not significant. The study reveals that decamethrin did not produce any serious fetotoxicity or teratogenicity in rats.
[Bhaumik A, Gupta PK; Indian Vet J 67 (3): 213-9 (1990)]**PEER REVIEWED**

The effect of the synthetic pyrethroid insecticide deltamethrin was investigated in mice in vivo for the induction of bone marrow chromosome aberrations and micronuclei in bone marrow and for sperm abnormalities. Technical deltamethrin (10, 15 and 20 mg/kg) was injected ip and the respective cells were fixed after 24 hr, 30 hr and 35 days for the observation of chromosome aberrations micronuclei and sperm abnormalities respectively. Additionally, route-response (ip, oral and sc), time-response (6, 24 and 48 hr) and acute-chronic (24 versus 120 hr) studies were conducted for the induction of chromosome aberrations by the highest dose (20 mg/kg) of deltamethrin. All the above test results showe significant increases over respective controls. Moreover, a linear relationship was evident between the dose of deltamethrin used and the frequencies (%) of chromosome aberrations, micronuclei or sperm abnormalities.
[Bhunya SP, Pati PC; Mutagenesis 5 (3): 229-32 (1990)]**PEER REVIEWED**

The pesticide deltamethrin, a synthetic pyrethroid, was studied for carcinogenicity in long-term experiments in mice and rats. Mice were given deltamethrin by gavage in arachis oil at 0, 1, 4 or 8 mg/kg body wt for 2 yr. A group of untreated controls was also available. Rats received 0, 3 or 6 mg/kg body wt deltamethrin in arachis oil for 2 yr. In mice, an increased incidence of lymphomas was observed in the groups receiving 1 and 4 mg/kg body wt, but not in the group treated with 8 mg/kg body wt Deltamethrin. In rats, an increased incidence of thyroid tumours was noted, but, no clear dose-response relationship was shown. Deltamethrin does not appear to be carcinogenic in mice or rats, but further studies are needed on the group of compounds to which this substance belongs.
[Cabral J RP et al; Cancer Lett 49 (2): 147-64 (1990)]**PEER REVIEWED**

The possibility that deltamethrin induced tumors when given orally to inbred C57BL/6 mice and BDVI rats was investigated. Dosages were as follows: 30 male and 30 female mice received 1.0 or 4.0 mg/kg body weight deltamethrin; 50 animals of each sex received 8.0 mg/kg deltamethrin; and 50 male and 50 female rats received 0 3.0, or 6.0 mg/kg dose levels of deltamethrin. All animals were treated 5 days per week for 104 wk. The experiments were terminated when the animals were 120 wk of age. An increased incidence of lymphomas was noted in the groups of mice receiving 1 and 4 mg/kg doses but not in the group treated with 8 mg/kg. An increased incidence of thyroid tumors was noted in rats, with a significant increase observed in the incidence of thyroid adenomas in males and females receiving the 3 and 6 mg/kg deltamethrin doses, respectively. However no dose response relationship or treatment related increase in tumor incidence related to deltamethrin exposure could be indicated. It was concluded that deltamethrin does not appear to be carcinogenic in either mice or rats, however, further investigations are needed on the group of compounds to which deltamethrin belongs.
[Cabral JRP et al; Cancer Lett 49 (2): 147-52 (1990)]**PEER REVIEWED**

The release of (3)H neurotransmitters was used as a functional assay to assess the actions of selected neurotoxins on the synaptosomal membranes prepared from the invertebrate nervous systems of squid and house fly. A reproducible release of (3)H neurotransmitter was evoked by pulsed-depolarization in the presence of elevated K+ or of veratridine. Pretreatment with deltamethrin resulted in a substantial enhancement of (3)H neurotransmitter release during pulsed-depolarization. This enhanced neurotransmitter release was greatly reduced or absent when synaptosomes of knockdown resistant house flies were examined. No enhanced neurotransmitter release due to deltamethrin pretreatment was apparent from any synaptosomal preparation under non-depolarizing conditions. Under similar conditions, collaborative experiments demonstrated that deltamethrin causes a significant change in protein phosphorylation activities which follow depolarization. The most significant change caused by deltamethrin was the prolonged elevation of the level of phosphorylation on a number of key synaptic proteins beyond the normal time of their recovery to the dephosphorylated state. The most notable protein reacting to deltamethrin in this manner was calcium-calmodulin dependent protein kinase.
[Clark JM, Matsumura F; Pestic Sci 31 (1): 73-89 (1991)]**PEER REVIEWED**

The inhibitory action of synthetic pyrethroids and some chlorinated hydrocarbon insecticides on the neural calcium-calmodulin dependent protein phosphatase, calcineurin, was studied using one radiotracer and two colorimetric methods. It was found that all insecticidal Type II pyrethroids (cypermethrin, deltamethrin and fenvalerate) are potent inhibitors of isolated calcineurin from bovine brain. Their IC50 values were approximately 1 X 10-9 to 1 X 10-11 M. By contrast, neither noninsecticidal chiral isomers of these pyrethroids, neuroactive Type I pyrethroids nor neuroactive chlorinated hydrocarbon insecticides showed comparable potencies against this enzyme. To confirm the action of Type II pyrethroid in situ, isolated intact rat brain synaptosomes were incubated with (32)P phosphoric acid and subsequently depolarized in the presence and absence of 0.1 uM deltamethrin. As expected, there was a sharp rise in protein phosphorylation due to the action of calcineurin. deltamethrin caused a distinct delay in the dephosphorylation process. The results clearly indicate that calcineurin is specifically inhibited by Type II pyrethroids.
[Enan E, Matsumura F; Biochem Pharmacol 43 (8): 1777-84 (1992)]**PEER REVIEWED**

Effects of deltamethrin, a powerful synthetic pyrethroid, on the protein phosphorylation activity in the intact rat brain synaptosome during the time course of depolarization induced changes were studied. For this purpose, depolarization was induced either by veratridine or high concentration of K+. The level of phosphorylation on various synaptic proteins was found to quickly rise for 15 to 30 sec and return to the resting level in about 3 min. Deltamethrin, when given to the synaptosomes 10 min prior to depolarization, caused stimulation on this depolarization-induced protein phosphorylation activity at > 1012 M concentration. To find the cause for such an action of deltamethrin, the effects of ion-channel blockers and calmodulin inhibitors on the same phosphorylation process were studied. The inhibitory effect of a Ca2+ -channel blocker, verapamil, and a Na+-channel blocker, tetrodotoxin, on the stimulatory action of deltamethrin was first established. However, in neither case were their actions complete. The former reduced the stimulatory effects of deltamethrin on synapsin I but not on calcium and calmodulin dependent protein kinase II (CaM-Kinase II), B50, or 38-kDa proteins. The latter could not inhibit the stimulatory action of deltamethrin on synapsin I. Even when both blocking agents were present, the stimulatory action of deltamethrin was apparent. The stimulatory effect of deltamethrin on the phosphorylation rate of phosphoproteins, synapsin I, calcium-calmodulin dependent protein kinase II and B50 was less when the entire external calcium chloride was replaced by barium chloride in the prelabeling medium. Again, even under these conditions, the stimulatory effect of deltamethrin was evident on all proteins examined. In addition, the effect of calmodulin-inhibition trifluoroperazine was tested in the same manner. This inhibitor was found to reduce the phosphorylation on all of the tested synaptosome-proteins except protein 38 kDa, where there was an increase in phosphorylation in the presence of deltamethrin, especially, at 30, 60, and 180 sec of depolarization. These results indicate that (a) deltamethrin's action is not limited to calmodulin or the sodium or the calcium channel, (b) it must stimulate the release of Ca2+ from the intracellular storage site(s), and (c) such a stimulatory action of deltamethrin may be recognized only when the synaptosomes are depolarized regardless of the method of depolarization.
[Enan E, Matsumura F; Pestic Biochem Physiol 39 (2): 182-95 (1991)]**PEER REVIEWED**

Two pyrethroids, bioallethrin and deltamethrin, affect muscarinic cholinergic receptors in the neonatal mouse brain when given to suckling mice during the period of rapid brain growth. Such early exposure to these pyrethroids can also lead to permanent changes in the muscarinic cholinergic receptors and behavior in the mice as adults. In the present study, male NMRI mice were given bioallethrin (0.7 mg), deltamethrin (0.7 mg), or a 20% fat emulsion vehicle (10 ml) per kg of body wt per os once daily between the 10th and 16th postnatal day. The mice were subjected to behavioral tests upon reaching the age of 17 days and at 4 mo. Within 1-2 wk after the behavioral tests the mice were killed by decapitation and crude synaptosomal fractions (P2) were prepared from the cerebral cortex, hippocampus, and striatum. The densities of muscarinic cholinergic receptors were assayed by measuring the amounts of quinuclidinyl benzilate specifically bound in the P2 fraction. The proportions of high affinity and low affinity binding sites of muscarinic cholinergic receptors were assayed in a displacement study using quinuclidinyl benzilate/carbachol. The behavioral tests at an adult age of 4 mo indicated a significant increase in spontaneous motor behavior in both bioallethrin and deltamethrin treated mice. There was also a significant decrease and a tendency toward a decrease in the density of muscarinic cholinergic receptorsin the cerebral cortex in mice receiving bioallethrin and deltamethrin, respectively. The proportions of high affinity and LA-binding sites of muscarinic cholinergic receptors were not changed. This study further supports that disturbances of the cholinergic system during rapid development in the neonatal mouse can lead to permanent changes in cholinergic and behavioral variables in the animals as adults.
[Eriksson P, Fredriksson A; Toxicol Appl Pharmacol 108 (1): 78-85 (1991)]**PEER REVIEWED**

Effects of deltamethrin, a powerful pyrethroid insecticide, on the protein phosphorylation and dephosphorylation processes during depolarization in rat brain synaptosomes were studied by using (32)P phosphoric acid as a starting radio-tracer and high external concentration of potassium ions or veratridine (1 X 10-5 M) as depolarizing agents. At the onset of depolarization there was a quick rise in phosphorylation in various synaptic proteins for about 15-30 s followed by a gradual decline in levels of phosphorylation. The effect of deltamethrin (1 X 10-7 M) on this system was found to be dependent on the length of preincubation of the synaptosome with the pesticide prior to depolarization. At an early stage (0-3 min preincubation period) it caused a modest suppression of protein phosphorylation activities. When the period of deltamethrin preincubation was extended to 5-20 min, however, it caused a significant increase in protein phosphorylation throughout the depolarization period. At the alter stage of the action of deltamethrin (eg preincubation period of 30-40 min), deltamethrin treated synaptosomes no longer responded to the depolarization signal to raise the level of phosphorylation on many proteins. These results indicate that deltamethrin's actions on the synaptic process are complex. Depending on the length of exposure, its effects on protein phosphorylation responses in intact synaptosomes could be either stimulatory or inhibitory. To study the cause of deltamethrin induced synaptic block at the later stage, effects of deltamethrin on protein kinases were studied by using lysed synaptic membranes with (gamma-(32)P)ATP. Deltamethrin was shown to inhibit calcium-calmodulin-dependent protein phosphorylation activities at ... when given directly to the enzyme source 10 min prior to the addition of (32)P ATP. Such an observation helps to explain the inhibitory action of deltamethrin on protein phosphorylation which occurs at the late stage of its action (eg preincubation time > 20 min).
[Kanemoto Y et al; Pestic Sci 34 (3): 281-290 (1992)]**PEER REVIEWED**

Synthetic pyrethroids are neuropoisons acting on the axons in the peripheral and central nervous systems by interacting with sodium channels in mammals and/or insects. A single dose produces toxic signs in mammals, such as tremors, hyperexcitability, salivation, choreoathetosis, and paralysis. ... At near-lethal dose levels, synthetic pyrethroids cause transient changes in the nervous system, such as axonal swelling and/or breaks and myelin degeneration in sciatic nerves. They are not considered to cause delayed neurotoxicity of the kind induced by some organophosphorus compounds. /Synthetic prethroids/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.13 (1990)]**PEER REVIEWED**

Synthetic pyrethroids have been shown to be toxic for fish, aquatic arthropods, and honeybees in laboratory tests. But, in practical usage, no serious adverse effects have been noticed because of the low rates of application and lack of persistence in the environment. The toxicity of synthetic pyrethroids in birds and domestic animals is low. /Synthetic pyrethroids/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.13 (1990)]**PEER REVIEWED**

The in vitro effects of pyrethroids on the mitogenic responsiveness of murine splenic lymphocytes to concanavalin A and lipopolysaccharide were determined. Allethrin was the most potent inhibitor, with effective concn in the range of 1X10-6 to 1.5X10-5 M. The results support the possibility of immune suppression by pyrethroid exposure. /Pyrethroids/
[Stelzer KJ, Gordon MA; Res Commun Chem Pathol Pharmacol 46 (1): 137-50 (1984)]**PEER REVIEWED**

Following absorption through the chitinous exoskeleton of arthropods, pyrethrins stimulate the nervous system, apparently by competitively interfering with cationic conductances in the lipid layer of nerve cells, thereby blocking nerve impulse transmissions. Paralysis and death follow. /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements). 3203]**PEER REVIEWED**

Non-systemic insecticide with contact and stomach action. Fast-acting.
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

Deltamethrin was dissolved in corn oil and administered by gastric intubation at doses of 0, 2.5 mg/kg body weight to Sprague-Dawley rats from day 7 of gestation to day 15 of lactation. The dams were allowed to litter and rear their young: litters were reduced at birth to 4 males and 4 females per litter. The pups were weighed weekly and examined for the development of eye-opening, startle reflex, and air-righting. The litters were weaned on day 22 post-partum and the males discarded. Weekly weighing of the females continued and at 6 weeks of age they were tested in a circular open-field. There were no effects on parturition, litter size, or pup viability. Weights at birth were similar for all groups, but a dose-related depression in growth was observed during the pre-weaning period. This early diminution in pre-weaning weight appeared to have little effect on the morphological and behavioral parameters measured.
[WHO; Environmental Health Criteria 97: Deltamethrin p.78 (1990)]**PEER REVIEWED**

Groups of 10 male and 20 female Charles River rats were fed deltamethrin in the diet at 0, 2, 20, or 50 mg/kg and mated to begin a 3-generation, 2-litter (first generation, 3 litter) standard reproduction study. Parental body weights and food consumption were recorded during the study. After weaning of the second litter, the surviving parent rats were sacrificed and necropsied. Five male and 5 female pups of the F3b generation were necropsied. No changes relevant to treatment were observed in general behavior or survival of parent rats or pups. The body weight of F0 males of the 50 mg/kg group was decreased from week 11 onwards. There were some slight decreases in mean food consumption of F1 male parent rats in the 50 mg/kg group. The basic reproduction indices (fertility, gestation, lactation, viability, and litter size) were not affected by the treatment. However, the mean pup weight in some litters, especially in the 50 mg/kg group, was slightly decreased in comparison to the controls on day 21 lactation. Gross external examination did not reveal any abnormalities. No gross or microscopic lesions of treatment-related significance or significant effects on the organ weights of the F3b generation were observed.
[WHO; Environmental Health Criteria 97: Deltamethrin p.77 (1990)]**PEER REVIEWED**

The Type II /poisoning/ syndrome, also known as the "CS syndrome," is produced by those esters containing the alpha-cyano substituent and elicits intense hyperactivity, incoordination, and convulsions in cockroaches, in contrast to rats, which display burrowing behavior, coarse tremors, clonic seizures, sinuous writhing (choreoathetosis), and profuse salivation without lacrimation; hence the term CS (choreoathetosis/salivation) syndrome. /Pyrethroid esters containing the alpha-cyano substituent/
[Klaassen, C.D., M.O. Amdur, Doull J. (eds.). Casarett and Doull's Toxicology. The Basic Science of Poisons. 5th ed. New York, NY: McGraw-Hill, 1995. 666]**PEER REVIEWED**

Tissue culture experiments have shown that the dorsal root ganglion is more sensitive to deltamethrin than the spinal cord or peripheral nerve fibres. The morphologial alterations observed in the neuronal bodies of the ganglia may reflect some perturbation of the ionic equilibrium (Na+ and Ca+).
[WHO; Environmental Health Criteria 97: Deltamethrin p.82 (1990)]**PEER REVIEWED**

Pyrethroid-induced motor symptoms, i.e., deltamethrin-induced writhing and cismethrin-induced tremor, were studied, using a number of pharmacological agents, in intact conscious rats and spinal rats. The results suggest that pyrethroid-induced motor-symptoms, i.e., writhing and tremor, are mediated via a spinal site of action, probably involving interneurons. Deltamethrin-induced "non-motor" symptoms, i.e., increase in brain blood flow and blood glucose may result from a supraspinal component of deltamethrin activity. In contrast, the cardiovascular effects of deltamethrin are mediated via a peripheral site of action.
[WHO; Environmental Health Criteria 97: Deltamethrin p.82 (1990)]**PEER REVIEWED**

The symptoms of pyrethrin poisoning follow the typical pattern of nerve poisoning: (1) excitation, (2) convulsions, (3) paralysis, and (4) death. The effects of pyrethrins on the insect nervous system closely resemble those of DDT, but are apparently much less persistent. Regular, rhythmic, and spontaneous nerve discharges have been observed in insect and crustacean nerve-muscle preparations poisoned with pyrethrins. The primary target of pyrethrins seems to be the ganglia of the insect central nervous system although some pyrethrin-poisoning effect can be observed in isolated legs. /Pyrethrins/
[Matsumura, F. Toxicology of Insecticides. 2nd ed. New York, NY: Plenum Press, 1985. 147]**PEER REVIEWED**

The low toxicity of pyrethroids in mammals is due largely to their rapid biotransformation by ester hydrolysis and/or hydroxylation. /Pyrethroids/
[Hardman, J.G., L.E. Limbird, P.B. Molinoff, R.W. Ruddon, A.G. Goodman (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 9th ed. New York, NY: McGraw-Hill, 1996. 1687]**PEER REVIEWED**

 

Non-Human Toxicity Values:

LD50 Rat male oral 128 mg/kg (in vegetable oil)
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

LD50 Dog (male & female), oral, in capsules >300 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.63 (1990)]**PEER REVIEWED**

LD50 Dog (male & female), oral, in PEG 200 2 mg/kg /Techanical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.63 (1990)]**PEER REVIEWED**

LD50 Rabbit, dermal, in PEG 400 >2000 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.63 (1990)]**PEER REVIEWED**

LD50 Rat (male), oral, in sesame oil 128 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (female), oral, in sesame oil 139 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (male), oral, in PEG 200 67 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (female), oral, in PEG 200 86 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (male adult), oral, in peanut oil 52 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (female adult), oral, in peanut oil 31 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (female weanling), oral, in peanut oil 50 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat dermal, 700 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (male & female), dermal, in methylcellulose (1%) > 2940 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Rat (female adult), dermal, in xylene > 800 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LC50 (male & female), inhalation, dust 600 mg/cu m/6 hr /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.61 (1990)]**PEER REVIEWED**

LD50 Mouse (male), oral, in sesame oil 33 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.62 (1990)]**PEER REVIEWED**

LD50 Mouse (female), oral, in sesame oil 34 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.62 (1990)]**PEER REVIEWED**

LD50 Mouse (male), oral, in PEG 200 21 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.62 (1990)]**PEER REVIEWED**

LD50 Mouse (female), oral, in PEG 200 19 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.62 (1990)]**PEER REVIEWED**

LD50 Mouse ip 33 mg/kg /Technical grade/
[WHO; Environmental Health Criteria 97: Deltamethrin p.62 (1990)]**PEER REVIEWED**

LD50 Rat female oral 139 mg/kg (in vegetable oil)
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

LD50 Rat oral > 5000 mg (of 5 g/l UL)/kg
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

LD50 Rabbit percutaneous > 2000 mg/kg
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

LC50 Rat inhalation 785 mg/cu m/2 hr
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 993]**PEER REVIEWED**

LD50 Rat iv 2526 mg/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 993]**PEER REVIEWED**

LD50 Mouse intracerebral 26,100 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 993]**PEER REVIEWED**

LD50 Dog iv 3440 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 993]**PEER REVIEWED**

Ecotoxicity Values:

LC50 Alburnus alburnus (Bleak) (static condition) 0.69 ug/l/96 hr /Technical product/
[WHO; Environmental Health Criteria 97: Deltamethrin p.49 (1990)]**PEER REVIEWED**

LC50 Brachydanio rerio (Zebra fish) (flow system, static condition) 2.0 ug/l/96 hr /Technical product/
[WHO; Environmental Health Criteria 97: Deltamethrin p.49 (1990)]**PEER REVIEWED**

Cyrpinus carpio (Common carp) (flow system, static condition) 1.84 ug/l /96 hr 0.86 ug/l/96 hr /Technical product/
[WHO; Environmental Health Criteria 97: Deltamethrin p.49 (1990)]**PEER REVIEWED**

lctalurus nebulosus (Brown bullhead) (flow system, static conditions) ug/l/96 hr /Technical product/
[WHO; Environmental Health Criteria 97: Deltamethrin p.49 (1990)]**PEER REVIEWED**

LC50 Lctalurus punctatus (Channel catfish) (flow system, static condition) 0.63 ug/l/96 hr /Technical product/
[WHO; Environmental Health Criteria 97: Deltamethrin p.49 (1990)]**PEER REVIEWED**

LC50 Lepomis gibbosus (Pumpkinseed sunfish) (flow system, static condition) 0.58 ug/l/96 hr
[WHO; Environmental Health Criteria 97: Deltamethrin p.50 (1990)]**PEER REVIEWED**

LC50 Lepmois machrochirus (Bluegill sunfish) (flow system, static condition) 1.2 ug/l/96 hr
[WHO; Environmental Health Criteria 97: Deltamethrin p.50 (1990)]**PEER REVIEWED**

LC50 Rhodeus sericeus amarus (static condition) 1.12 ug/l/96 hr
[WHO; Environmental Health Criteria 97: Deltamethrin p.50 (1990)]**PEER REVIEWED**

LC50 Salmo gairdneri (Rainbow trout) (flow system, static conditions) 0.39 ug/l/96 hr
[WHO; Environmental Health Criteria 97: Deltamethrin p.50 (1990)]**PEER REVIEWED**

LC50 Salmo salar 1.97 ug/l/96 hr
[WHO; Environmental Health Criteria 97: Deltamethrin p.50 (1990)]**PEER REVIEWED**

LC50 Sarotherodon mossambicuse (flow system, static conditions) 3.5 ug/l/96 hr
[WHO; Environmental Health Criteria 97: Deltamethrin p.50 (1990)]**PEER REVIEWED**

LD50 Mallard duck oral >4640 mg/kg
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

LC50 Quail dietary >5620 mg/kg diet/8 day
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

Metabolism/Pharmacokinetics:

Metabolism/Metabolites:

Deltamethrin (1 ug) was incubated at 37 deg C for 30 min with each of the following mouse microsome preparations; a) tetraethyl pyrophosphate (TEPP)-treated microsomes (no esterase and oxidase activity); b) normal microsomes (esterase acivity); c) TEPP-treated microsomes plus NADPH (oxidase activity); and d)normal microsomes plus NADPH (esterase plus oxidase activity). Deltamethrin was more rapidly metabolized under the oxidase system than under the esterase system. The major site of ring hydroxylation was 4'-position and the secondary site was the 5-position. The trans methyl group was an important site of hydroxylation of the esters and cis methyl oxidation was evident in the metabolites of the cleaved acid moiety. The preferred sites of hydroxylation were as follows; trans of dimethyl group, 4'-position in the phenol group, and cis of the dimethyl group was equal to the 5-position in the phenoxy group. Cleavage of deltamethrin to cyanohydrin may result from both esterase and oxidase enzyme activities, since larger amounts of the cleaved products were evident in the oxidase system. ... However, at a much higher (approximately 35-fold) concentration of deltamethrin than that in the above study, it was not detectably hydrolysed. ... Deltamethrin was hydrolysed by esterases in the blood, brain, kidney, and stomach of mice yielding PBald and PBacid.
[WHO; Environmental Health Criteria 97: Deltamethrin p.46 (1990)]**PEER REVIEWED**

In a metabolic study, (14)C-deltamethrin was administered orally to lactating dairy cows at the rate of 10 mg/kg body weight per day for 3 consecutive days. It was poorly absorbed and mainly eliminated in the feces as unchanged deltamethrin. Only 4-6% of the administered (14)C was eliminated in the urine, and 0.42-1.62% was secreted in the milk. The radiocarbon contents of various tissues were generally very low with the exception of those of the liver, kidney, and fat, which were higher. Deltamethrin degradation occured by cleavage of the ester bond, as already reported in rats and mice. The enzymes responsible for the ester bond cleavage were located in cow liver homogenate, mainly in the microsomal fraction, as seen in an in vitro study. Metabolites resulting from ester bond cleavage further metabolized and/or conjugated, resulting in a large number of compounds excreted in the urine. In the milk, the major identifiable radiolabelled compound was deltamethrin.
[WHO; Environmental Health Criteria 97: Deltamethrin p.45 (1990)]**PEER REVIEWED**

The major metabolic pathways of deltamethrin in mice were similar to those in rats, though there were some differences. These included the presence of more unchanged deltamethrin in mouse feces than in rat feces. In mouse feces, there were 4 monohydroxy ester metabolites (2'-OH-, 4'-OH-, 5-OH-, and trans-OH-deltamethrin and one dihydroxy metabolite (4'-OH-trans-OH- deltamethrin) that were not found in mouse urine. Major metabolites from the acid moiety in mice were Br2CA, trans-OH-Br2CA, and their glucuronide and sulfate conjugates. Among them, trans-OH-Br2CA-sulfate was detected only in mice, but not in rats. Compared with rats, much larger amounts of trans-OH-Br2CA and its conjugates were formed in mice. A major metabolite of the alcohol moiety in mice was the taurine conjugate of PBacid in the urine, which was not detected in rats. Generally, mice produced smaller amounts of phenolic compounds compared with rats. Also, 3-phenoxybenzaldehyde (24) (PBald), 3-phenoxybenzyl alcohol (PBalc), and its glucuronide, and glucuronides of 3-(4-hydroxyphenoxy)benzyl alcohol (4'-OH-PBalc) and 5-hydroxy-3-penoxybenzoic acid (5-OH-PBacid) were found in mice, but not in rats. When mice were given an ip dose of (14) C-deltamethrin with or without piperonyl butoxide (PBO) and/or S,S,S-tributylphosphorotrithioate (DEF), the same metabolites were obtained as with oral administration. However, DEF decreased the hydrolytic products relative to the controls, while PBO decreased the oxidation products.
[WHO; Environmental Health Criteria 97: Deltamethrin p.44 (1990)]**PEER REVIEWED**

Sulfate of 4'-OH-PBacid accounted for about 50% of the dose, together with small amounts of free (4%) and glucuronide forms (2%). The CN group was converted mainly to thiocyanate and, in small amounts, to ITCA. The trans-isomer of deltamethrin was also rapidly metabolized and yielded almost the same metabolties as deltamethrin, though 5-OH-derivative was found in the cis-isomer, but not in the trans-isomer.
[WHO; Environmental Health Criteria 97: Deltamethrin p.43 (1990)]**PEER REVIEWED**

When a single oral dose of (14)C-(acid-, alcohol-, or cyano-labelled) deltamethrin was administered to male mice at 1.7-4.4 mg/kg, the acid moiety and the aromatic portion of the alcohol moiety were rapidly and almost completely excreted, whereaa the CN group was excreted relatively slowly.
[WHO; Environmental Health Criteria 97: Deltamethrin p.43 (1990)]**PEER REVIEWED**

After oral administration to male rats at 0.64-1.60 mg/kg the major metabolic reactions of deltamethrin /observed/ were oxidation (at the trans methyl relative to carbonyl group of the acid moiety and the 2'-4'-, and 5-position of the alcohol moiety), cleavage of the ester linkage, and conversion of the cyano portion to thio-cyanate and 2-iminothiazolidine-4-carboxylic acid (ITCA). These carboxylic acid and phenol derivatives were conjugated with sulfuric acid, glycine, and/or glucuronic acid. The major fecal metabolites were unchanged deltamethrin, accounting for 13-21% of the dose, followed by 4'-OH-(10) and 5-OH-deltamethrin, and a trace amount of 2'-OH-deltamethrin. Intact deltamethrin and the 4'-OH-derivative appeared not only as the administered S-epimer, but also in parts as the R-epimer, probably due to artifactual racemization on exchange of the alpha-position hydrogen in methanol solution. The metabolites from the acid moiety were mostly 3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropanecarboxlic acid (Br2CA) in free form (10% of the dose), glucuronide (51%) and glycine (trace level) conjugates, and OH-Br2CA in free form and glucuronide conjugate (<1%). The major metabolites of the aromatic portion of the alcohol moiety were 3-phenoxybenzoic acid (PBacid) in free form (5%), and glucuronide (13%) and glycine (4%) conjugates and its 4'-hydroxy derivative (4'-OH-PBacid).
[WHO; Environmental Health Criteria 97: Deltamethrin p.41 (1990)]**PEER REVIEWED**

3-Hydroxybenzoic acid (both free and conjugates) was detected in the excreta of hens fed deltamethrin or fenvalerate. The diphenyl ether cleavage of 3-phenoxybenzaldehyde is a major route, probably via 3-phenoxybenzoic acid, in chickens.
[Akhtar MH; J Agric Food Chem 38 (6): 1417-22 (1990)]**PEER REVIEWED**

The metabolic pathways for the breakdown of the pyrethroids vary little between mammalian species but vary somewhat with structure. ... Essentially, pyrethrum & allethrin are broken down mainly by oxidation of the isobutenyl side chain of the acid moiety & of the unsaturated side chain of the alcohol moiety with ester hydrolysis playing & important part, whereas for the other pyrethroids ester hydrolysis predominates. /Pyrethrum and pyrethroids/
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 588]**PEER REVIEWED**

The relative resistance of mammals to the pyrethroids is almost wholly attributable to their ability to hydrolyze the pyrethroids rapidly to their inactive acid & alcohol components, since direct injection into the mammalian CNS leads to a susceptibility similar to that seen in insects. Some addtl resistance of homeothermic organisms can also be attributed to the negative temperature coefficient of action of the pyrethroids, which are thus less toxic at mammalian body temperatures, but the major effect is metabolic. Metabolic disposal of the pyrethroids is very rapid, which means that toxicity is high by the iv route, moderate by slower oral absorption, & often unmeasureably low by dermal absorption. /Pyrethroids/
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 588]**PEER REVIEWED**

FASTEST BREAKDOWN IS SEEN WITH PRIMARY ALCOHOL ESTERS OF TRANS-SUBSTITUTED ACIDS SINCE THEY UNDERGO RAPID HYDROLYTIC & OXIDATIVE ATTACK. FOR ALL SECONDARY ALCOHOL ESTERS & FOR PRIMARY ALCOHOL CIS-SUBSTITUTED CYCLOPROPANECARBOXYLATES, OXIDATIVE ATTACK IS PREDOMINANT. /PYRETHROIDS/
[The Chemical Society. Foreign Compound Metabolism in Mammals. Volume 5: A Review of the Literature Published during 1976 and 1977. London: The Chemical Society, 1979. 469]**PEER REVIEWED**

Pyrethrins are reportedly inactivated in the GI tract following ingestion. In animals, pyrethrins are rapidly metabolized to water soluble, inactive compounds. /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements). 3203]**PEER REVIEWED**

Synthetic pyrethroids are generally metabolized in mammals through ester hydrolysis, oxidation, and conjugation, and there is no tendency to accumulate in tissues. In the environment, synthetic pyrethroids are fairly rapidly degraded in soil and in plants. Ester hydrolysis and oxidation at various sites on the molecule are the major degradation processes. /Synthetic pyrethroids/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.13 (1990)]**PEER REVIEWED**

In rats, following oral administration, elimination occurs within 2-4 days. The phenyl ring is hydroxylated, the ester bond hydrolyzed, and the acid moiety is eliminated as the glucuronide and glycine conjugated.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

In a feeding study, deltamethrin was administered twice daily to lactating dairy cows in portions of their daily feed at the rate of 2 or 10 mg/kg diet for 28 consecutive days. ... Br2CA (3-(2,2-dibromovinyl)-2,2-dimethylcyclopro-panecarboxylic acid) and PBacid (3-phenoxybenzoic acid) were the only metabolites detected in the milk and tissues of treated cows. In all cases, they were found at trace levels of < 0.0235 mg/l and < 0.034 mg/l, respectively. These two metabolites were also previously identified in rats and mice as the major degradation productions of deltamethrin.
[WHO; Environmental Health Criteria 97: Deltamethrin p.45 (1990)]**PEER REVIEWED**

Absorption, Distribution & Excretion:

In rats, following oral administration, elimination occurs within 2-4 days. The phenyl ring is hydroxylated, the ester bond hydrolyzed, and the acid moiety is eliminated as the glucuronide and glycine conjugated.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Three young male human volunteers underwent a complete medical check-up one week prior to the morning of the study. Each of them received a single dose of 3 mg of (14)C deltamethrin mixed in 1 g glucose and diluted first in 10 ml polyethylene glycol300 and again in 150 ml water. Total radioactivity was 1.8 + or - 0.9 mBq. Samples of blood, urine, saliva, and feces were taken at intervals over 5 days. Clinical and biological examinations were performed every 12 hr during the trial and one week after its termination. Radioactivity in the biological samples was measured with a liquid scintillation spectrometer. The clinical and biological checks did not detect any abnormal findings. There were no signs of side effects ... either during or after the trial period. The maximum plasma radioactivity appeared between 1 and 2 hr after administration of the product, and remained over the detection limit (0.2 KBq/l) during the 48 hr. The apparent elimination half-life was between 10.0 and 11.5 hr. The radioactivity of blood cells, as well as the saliva, was extremely low. Urinary excretion was 51-50% of the initial radioactivity; 90% of this radioactivity was excreted during the 24 hr following absorption. The apparent half-life of urinary excretion was 10.0-13.5 hr, which is consistent with the plasma data. Fecal elimination at the end of the observation period represented 10-26% of the dose. The total fecal plus urine elimination was around 64-77% of the initial dose after 96 hr.
[WHO; Environmental Health Criteria 97: Deltamethrin p.47 (1990)]**PEER REVIEWED**

In a feeding study, deltamethrin was administered twice daily to lactating dairy cows in portions of their daily feed at the rate of 2 or 10 mg/kg diet for 28 consecutive days. The level of 2 mg/kg diet was the residue level found in a recently treated pasture, whereas 10 mg/kg diet was five times this level. Deltamethrin residues in the milk were dose-dependent and appeared to reach a plateau between 7 and 9 days after the start of treatment. At the high deltamethrin intake of 10 mg/kg diet, the deltamethrin residue in milk was about 0.025 mg/l. Deltamethrin residues in tissues were measured 1, 4, and 9 days after the last dose. At the 10 mg/kg diet intake, very small amounts of deltamethrin residues were found in the liver (<0.005 mg/kg), kidney )<0.002 mg/kg), and muscle (0.002-0.014 mg/kg). Residues in fat were about 0.04 mg/kg and 0.2 mg/kg for the 2 and 10 mg/kg intake, respectively. Depletion of deltamethrin in milk was very rapid (estimated half-life was about 1 day); while in fat (renal and subcutaneous) the half-life was 7-9 days. Br2CA (3-(2,2-dibromovinyl)-2,2-dimethylcyclopro-panecarboxylic acid) and PBacid (3-phenoxybenzoic acid) were the only metabolites detected in the milk and tissues of treated cows. In all cases, they were found at trace levels of < 0.0235 mg/l and < 0.034 mg/l, respectively. These two metabolites were also previously identified in rats and mice as the major degradation products of deltamethrin.
[WHO; Environmental Health Criteria 97: Deltamethrin p.45 (1990)]**PEER REVIEWED**

In a metabolic study, (14)C-deltamethrin was administered orally to lactating dairy cows at the rate of 10 mg/kg body weight per day for 3 consecutive days. It was poorly absorbed and mainly eliminated in the feces as unchanged deltamethrin. Only 4-6% of the administered (14)C was eliminated in the urine, and 0.42-1.62% was secreted in the milk. The radiocarbon contents of various tissues were generally very low with the exception of those of the liver, kidney, and fat, which were higher. Deltamethrin degradation occurred by cleavage of the ester bond, as already reported in rats and mice. The enzymes responsible for the ester bond cleavage were located in cow liver homogenate, mainly in the microsomal fraction, as seen in an in vitro study. Metabolites resulting from ester bond cleavage further metabolized and/or conjugated, resulting in a large number of compounds excreted in the urine. In the milk, the major identifiable radiolabelled compound was deltamethrin.
[WHO; Environmental Health Criteria 97: Deltamethrin p.45 (1990)]**PEER REVIEWED**

The fate of (14)C-deltamethrin was examined in Leghorn hens. When laying hens were administered 7.5 mg of (14)C-labelled deltamethrin/hen per day orally for 3 consecutive days, about 83% and 90% of the administered (14)C was eliminated during the first 24 hr and 48 hr after dosing, respectively. Tissue residues were generally very low with the exception of those in the liver and kidney. Very low levels of residues were found in eggs obtained within the first 24 h after dosing, but levels increased reaching a peak within 48 hr of the last dose. Residue levels were higher in the yolk (up to 0.6 mg/kg) than the albumen (up to 0.2 mg/kg), which is probably related to the lipid content of yolks. Metabolites were the same as those found in rats and mice.
[WHO; Environmental Health Criteria 97: Deltamethrin p.46 (1990)]**PEER REVIEWED**

The comparison between the excreted radioactivity of (14)C- deltamethrin in rats treated by the percutaneous route and iv (controls) showed the only 3.6% of the dosage applied on the skin was absorbed and excreted in 24 hr with 1.1% excreted during the first 6 hr. Since rat skin is more permeable than human skin, the uptake of deltamethrin through the human skin should be relatively weak.
[WHO; Environmental Health Criteria 97: Deltamethrin p.44 (1990)]**PEER REVIEWED**

After oral administration to male rats at 0.64-1.60 mg/kg, the acid and alcohol moieties of deltamethrin were almost completely eliminated from the body within 2-4 days. On the other hand, the cyano group was eliminated more slowly, the total recovery during 8 days being 79% of the radiocarbon dose (43% and 36% in the urine and feces, respectively). Tissue residues of deltamethrin labelled with (14)C at the dibromovinyl carbon in the acid moiety and the benzylic carbon in the alcohol moiety were generally very low, whereas residue levels in the fat were somewhat higher (0.1-0.2 mg/kg). Residue levels of the radiocarbon derived from the cyano group were relatively high, especially in the skin and stomach. Essentially, all the radiocarbon in the stomach was thiocyanate. No noticable (14)CO2 was evolved from any of the radioactive preparations, including the CN-labelled group, in contrast to the CN group from fenvalerate, which yielded (14)CO2 in considerable amounts.
[WHO; Environmental Health Criteria 97: Deltamethrin p.41 (1990)]**PEER REVIEWED**

Lactating dairy cows were fed deltamethrin (2 or 10 mg/kg feed) for 28 consecutive days and deltamethrin residues were then measured in milk and tissues. Deltamethrin residues were higher relative to dose administered. The order of relative concentrations of deltamethrin in tissues, measured 1, 4, and 9 days after the last dose was: renal fat > subcutaneous fat > forequarter muscle > hindquarter muscle > liver > kidney. Depletion of deltamethrin residues in milk was very rapid indicating that half-life of the insecticide of about 1 day. Trace amounts of deltamethrin metabolites 3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (<0.0235 ppm) and 3-phenoxybenzoic acid (< 0.034 ppm) were also detected in milk and tissues of treated cows.
[Akhtar MH et al; J Environ Sci Health Part B Pestic Food Contam Agric Wastes 27 (3): 235-53 (1992)]**PEER REVIEWED**

/PYRETHROIDS/ READILY PENETRATE INSECT CUTICLE AS SHOWN BY TOPICAL LD50 TO PERIPLANETA (COCKROACH) ... /PYRETHROIDS/
[White-Stevens, R. (ed.). Pesticides in the Environment: Volume 1, Part 1, Part 2. New York: Marcel Dekker, Inc., 1971. 75]**PEER REVIEWED**

WHEN RADIOACTIVE PYRETHROID IS ADMIN ORALLY TO MAMMALS, IT IS ABSORBED FROM INTESTINAL TRACT OF THE ANIMALS & DISTRIBUTED IN EVERY TISSUE EXAMINED. EXCRETION OF RADIOACTIVITY IN RATS ADMIN TRANS-ISOMER: DOSAGE: 500 MG/KG; INTERVAL 20 DAYS; URINE 36%; FECES 64%; TOTAL 100%. /PYRETHROIDS/
[MIYAMOTO J; ENVIRON HEALTH PERSPECT 14: 15-28 (1976)]**PEER REVIEWED**

Pyrethrins are absorbed through intact skin when applied topically. When animals were exposed to aerosols of pyrethrins with piperonyl butoxide being released into the air, little or none of the combination was systemically absorbed. /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements). 3203]**PEER REVIEWED**

The distribution of (14)C-acid-, (14)C-alcohol-, and (14)C-cyano-labelled deltamethrin and selected metabolites in the liver, blood, cerebrum, cerebellum, and spinal cord /was studied/ after iv administration of a toxic, but non-lethal, dose (1.75 mg/kg) to rats. Approximately 50% of the dose was cleared from the blood within 0.7-0.8 min, after which the rate of clearance decreased. 3-Phenoxybenzoic acid (PBacid) was isolated from the blood in vivo, and was also the major metabolite when (14)C-alcohol-labelled deltamethrin was incubated with blood in vitro. Deltamethrin levels in the liver peaked at 7-10 nmol/g at 5 min and then decreased to 1 nmol/g by 30 min. In contrast, peak central nervous system levels of deltamethrin were achieved within 1 min (0.5 nmol/g), decreasing to 0.2 nmol/g at 15 min and remaining stable until 60 min. Peak levels of deltamethrin were not related to the severity of toxicity, though the levels of unextractable pentane radiolabel did appear to be correlated with signs of motor toxicity.
[WHO; Environmental Health Criteria 97: Deltamethrin p.43 (1990)]**PEER REVIEWED**

Although limited absorption may account for the low toxicity of some pyrethroids, rapid biodegradation by mammalian liver enzymes (ester hydrolysis and oxidation) is probably the major factor responsible. Most pyrethroid metabolites are promptly excreted, at least in part, by the kidney. /Pyrethroids/
[U.S. Environmental Protection Agency/Office of Prevention, Pesticides, and Toxic Substances. Reigart, J.R., Roberts, J.R. Recognition and Management ofPesticide Poisonings. 5th ed. 1999. EPA Document No. EPA 735-R-98-003, and available in electronic format at: http://www.epa.gov/pesticides/safety/healthcare 87]**PEER REVIEWED**

The cutaneous and gastrointestinal absorption of deltamethrin in humans has been demonstrated after acute poisonings due to occupational overexposure or ingestion of deltamethrin products. The presence of a deltamethrin metabolite (3-2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid) has been reported in the urine of people with acute deltamethrin intoxication, confirming the absorption and metabolic degradation of this insecticide in the human body.
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. V53 258 (1991)]**PEER REVIEWED**

Biological Half-Life:

Deltamethrin has a half-life in rat brain of 1-2 days, but it is rather more persistent in body fat, with a half-life of 5 days.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 595]**PEER REVIEWED**

Mechanism of Action:

The lowest concentration of deltamethrin to have an effect in crayfish stretch receptor neurons on sodium channels was 1X10-12 mol/l, but the response of the preparation to gamma-aminobutyric acid (GABA) appeared to be unaffected by concentrations of deltamethrin up to 1X10-7 mol/l. Although 1X10-6 mol/l deltamethrin had a slight effect on the GABA response of the dactyl abductor muscle, it appears that the majority of the effects of cyano-pyrethroids in invertebrates could be accounted for solely by their action on sodium channels.
[WHO; Environmental Health Criteria 97: Deltamethrin p.81 (1990)]**PEER REVIEWED**

The synthetic pyrethroids delay closure of the sodium channel, resulting in a sodium tail current that is characterized by a slow influx of sodium during the end of depolarization. Apparently the pyrethroid molecule holds the activation gate in the open position. Pyrethroids with an alpha-cyano group (e.g., fenvalerate) produce more prolonged sodium tail currents than do other pyrethroids (e.g., permethrin, bioresmethrin). The former group of pyrethroids causes more cutaneous sensations than the latter. /Synthetic pyrethroids/
[Ellenhorn, M.J. and D.G. Barceloux. Medical Toxicology - Diagnosis and Treatment of Human Poisoning. New York, NY: Elsevier Science Publishing Co., Inc. 1988. 1081]**PEER REVIEWED**

Interaction with sodium channels is not the only mechanism of action proposed for the pyrethroids. Their effects on the CNS have led various workers to suggest actions via antagonism of gamma-aminobutyric acid (GABA)-mediated inhibition, modulation of nicotinic cholinergic transmission, enhancement of noradrenaline release, or actions on calcium ions. Since neurotransmitter specific pharmacological agents offer only poor or partial protection against poisoning, it is unlikely that one of these effects represents the primary mechanism of action of the pyrethroids, & most neurotransmitter release is secondary to incr sodium entry. /Pyrethroids/
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 588]**PEER REVIEWED**

Electrophysiologically, pyrethrins cause repetitive discharges and conduction block. /Pyrethrins/
[Matsumura, F. Toxicology of Insecticides. 2nd ed. New York, NY: Plenum Press, 1985. 147]**PEER REVIEWED**

The interaction of a series of pyrethroid insecticides with the sodium channels in myelinated nerve fibers of the clawed frog, Xenopus laevis, was investigated using the voltage clamp technique. Of 11 pyrethroids, 9 insecticidally active cmpd induced a slowly decaying sodium tail current on termination of a step depolarization, whereas the sodium current during depolarization was hardly affected. /Pyrethroids/
[Vijverberg HP M et al; Biochem Biophys Acta 728 (1): 73-82 (1983)]**PEER REVIEWED**

Mode of action of pyrethrum & related cmpd has been studied more in insects & in other invertebrates than in mammals. This action involves ion transport through the membrane of nerve axons &, at least in invertebrates & lower vertebrates, it exhibits a negative temperature coefficient. In both of these important ways & in many details, the mode of action of pyrethrin & pyrethroids resembles that of DDT. Esterases & mixed-function oxidase system differ in their relative importance for metabolizing different synthetic pyrethroids. The same may be true of the constituents of pyrethrum, depending on strain, species, & other factors. /Pyrethrins and pyrethroids/
[Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982. 75]**PEER REVIEWED**

The interactions of natural pyrethrins and 9 pyrethroids with the nicotinic acetylcholine (ACh) receptor/channel complex of Torpedo electronic organ membranes were studied. None reduced (3)H-ACh binding to the receptor sites, but all inhibited (3)H-labeled perhydrohistrionicotoxin binding to the channel sites in presence of carbamylcholine. Allethrin inhibited binding noncompetitively, but (3H)-labeled imipramine binding competitively, suggesting that allethrin binds to the receptor's channel sites that bind imipramine. The pyrethroids were divided into 2 types according to their action: type A, which included allethrin, was more potent in inhibiting (3)H-H12-HTX binding and acted more rapidly. Type B, which included permethrin, was less potent and their potency increased slowly with time. The high affinities that several pyrethroids have for this nicotinic ACh receptor suggest that pyrethroids may have a synaptic site of action in addition to their well known effects on the axonal channels. /Pyrethrins and Pyrethroids/
[Abbassy MA et al; Pestic Biochem Physiol 19 (3): 299-308 (1983)]**PEER REVIEWED**

The primary target site of pyrethroid insecticides in the vertebrate nervous system is the sodium channel in the nerve membrane. Pyrethroids without an alpha-cyano group (allethrin, d-phenothrin, permethrin, and cismethrin) cause a moderate prolongation of the transient increase in sodium permeability of the nerve membrane during excitation. This results in relatively short trains of repetitive nerve impulses in sense organs, sensory (afferent) nerve fibers, and, in effect, nerve terminals. On the other hand the alpha-cyano pyrethroids cause a long lasting prolongation of the transient increase in sodium permeability of the nerve membrane during excitation. This results in long-lasting trains of repetitive impulses in sense organs and a frequency-dependent depression of the nerve impulse in nerve fibers. The difference in effects between permethrin and cypermethrin, which have identical molecular structures except for the presence of an alpha-cyano group on the phenoxybenzyl alcohol, indicates that it is this alpha-cyano group that is responsible for the long-lasting prolongation of the sodium permeability. Since the mechanisms responsible for nerve impulse generation and conduction are basically the same throughout the entire nervous system, pyrethroids may also induce repetitive activity in various parts of the brain. The difference in symptoms of poisoning by alpha-cyano pyrethroids, compared with the classical pyrethroids, is not necessarily due to an exclusive central site of action. It may be related to the long-lasting repetitive activity in sense organs and possibly in other parts of the nervous system, which, in a more advance state of poisoning, may be accompanied by a frequency-dependent depression of the nervous impulse. /Synthetic pyrethroids/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.89 (1990)]**PEER REVIEWED**

Pyrethroids also cause pronounced repetitive activity and a prolongation of the transient increase in sodium permeability of the nerve membrane in insects and other invertebrates. Available information indicates that the sodium channel in the nerve membrane is also the most important target site of pyrethroids in the invertebrate nervous system. /Synthetic pyrethroids/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.90 (1990)]**PEER REVIEWED**

In the electrophysiological experiments using giant axons of cray-fish, the Type II pyrethroids retain sodium channels in a modified continuous open state persistently, depolarize the membrane, and block the action potential without causing repetitive firing. /Pyrethroids type II/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.87 (1990)]**PEER REVIEWED**

Diazepam, which facilitates GABA reaction, delayed the onset of action of deltamethrin and fenvalerate, but not permethrin and allethrin, in both the mouse and cockroach. Possible mechanisms of the Type II pyrethroid syndrome include action at the GABA receptor complex or a closely linked class of neuroreceptor. /Pyrethroids type II/
[WHO; Environmental Health Criteria 99: Cyhalothrin p.87 (1990)]**PEER REVIEWED**

... Type II pyrethroids /containing the alpha-cyano substituent/ extend the time constant for inactivation by hundreds of milliseconds to seconds, causing a persistent depolarization and a frequency-dependent conduction block in sensory and motor axons, and prolonged repetitive firing of sensory end organs and muscle fibers. The depolarizing action would have a dramatic effect on the sensory nervous system because such neurons tend to discharge when depolarized even slightly, resulting in an increase in the number of discharges. /Pyrethroid esters containing the alpha-cyano substituent/
[Klaassen, C.D., M.O. Amdur, Doull J. (eds.). Casarett and Doull's Toxicology. The Basic Science of Poisons. 5th ed. New York, NY: McGraw-Hill, 1995. 668]**PEER REVIEWED**

Interactions:

Deltamethrin was hydrolysed in vitro by esterases in blood, brain, kidney, liver, and stomach preparations of mice. Pretreatment of mice with the oxidase inhibitor, pipronyl butoxide (PBO), or the esterase inhibitor, S,S,S-tributylphosphorotrithoiate (DEF), delayed metabolism of intraperitoneally administered deltamethrin. PBO or DEF made mice more sensitive to deltamethrin.
[WHO; Environmental Health Criteria 97: Deltamethrin p.81 (1990)]**PEER REVIEWED**

Plasma esterases, in addition to hepatic esterases, play a role in the metabolism of deltamethrin in mammals and cause its rapid detoxification by the oral route. In a potentiation study, a range of esterase inhibitors, consisting mainly of organophosphorus insecticides, was given to male rats in oral doses that inhibited 50% of the plasma cholinesterase. After 15 min, or 2 or 24 hr, an oral LD50 dose of deltamethrin EC formulation was given which showed potentiation with azinphos ethyl, omethoate, and dichlorvos. It appears that users must handle deltamethrin in these combinations very carefully because of their high toxicity. Acephate, monocrotophos, phosphamidon, parathion methyl, and the 2 controls did not act as potentiators.
[WHO; Environmental Health Criteria 97: Deltamethrin p.81 (1990)]**PEER REVIEWED**

The effect of deltamethrin pretreatment on the pharmacokinetics and metabolism of antipyrine was studied in male rats. The total plasma clearance of antipyrine was significantly decreased by deltamethrin pretreatment (20 mg/kg and 40 mg/kg daily for 6 days prior to antipyrine administration), while the elimination half-life at beta phase, the area under the concentration-time curve and the mean residence time of antipyrine were significantly increased. The magnitude of the observed changes was dose dependent. The urinary excretion of norantipyrine, 4-hydroxyantipyrine and 3-hydroxymethylantipyrine was decreased by 39%, 32% and 26%, respectively (p <0.001) in the presence of deltamethrin. In addition, the rate constants for formation of each of these metabolites were significantly decreased by an average of approximatel 71%. These results suggest that deltamethrin is capable of inhibiting oxidative metabolism, a finding which could be of clinical and toxicological significance.
[Anadon A et al; Arch Toxicol 65 (2): 156-9 (1991)]**PEER REVIEWED**

The effect of deltamethrin pretreatment on the pharmacokinetics and metabolism of antipyrine was studied in male rats. The total plasma clearance of antipyrine was significantly decreased by deltamethrin pretreatment (20 mg/kg and 40 mg/kg daily for 6 days prior to antipyrine administration), while the elimination half-life at beta phase, the area under the concentration-time curve and the mean residence time of antipyrine were significantly increased. The magnitude of the observed changes was dose dependent. The urinary excretion of norantipyrine, 4-hydroxyantipyrine and 3-hydroxymethylantipyrine was decreased by 39%, 32% and 26%, respectively (p < 0.001) in the presence of deltamethrin. In addition, the rate constants for formation of each of these metabolites were significantly decreased by an average of approximately 71%. These results suggest that deltamethrin is capable of inhibiting oxidative metabolism, a finding which could be of clinical and toxicological significance.
[Anadon A et al; Arch Toxicol 65 (2): 156-9 (1991)]**PEER REVIEWED**

There is a potential hazard in mixed intoxications by pyrethroids and organophosphate insecticides, due to the fact that low toxicity of pyrethroids on mammals is chiefly due to quick cleavage of molecule by esterases, which can be thwarted by esterase inhibitors. We have developed a method in order to measure the duration and the intensity of potentiation of deltamethrin by a variety of organophosphate compounds. It was demonstrated that some of them (azinphos, dichlorvos, dimethoate, fenitrothion, omethoate) induce an increase of toxicity of deltamethrin. But, the total toxicity of association of Deltamethrin with Dimethoate, Fenitrothion, is weak, and does not prohibit their use. Others (methyl-parathion, acephate, phosphamidon, monocrotophos) have no such effects, even if they have a very high intrinsic toxicity. Cholinesterase inhibitors of the carbamate group are ineffective. It is suggested that the potentiation is mainly in relation with the kinetic of esterase inhibition, which is different, and specific to each organophosphate compound. So, it is essential that a specific toxicological measurement must be performed with any different insecticide, in order to anticipate the danger of a mixed intoxication by pyrethroids and organophosphates.
[Audegond L et al; J Toxicol Clin Exp 9 (3): 163-76 (1989)]**PEER REVIEWED**

Dimethoate and omethoate, two common organophosphorus insecticides, induced a dose related increase in the frequency of sister chromatid exchanges in human lymphocytes in vitro (p of the regression lines less than 1). Two other common pesticides, the pyrethroid insecticide deltamethrin and the systemic fungicide benomyl, induced a modest increase in sister chromatid exchanges which bordered on statistical significance (p = 0.053 and 0.055, respectively). Mixtures of the four pesticides at total concentrations of 41.5 and 83 ug/ml (composed of 43% dimethoate, 43% omethoate, 12% deltamethrin and 1.2% benomyl) induced a dose-dependent increase in sister chromatid exchanges (p <0.01). The effects of these mixtures of pesticides were variable using lymphocytes from different individuals, although these differences did not attain statistical significance. Moreover, low concentrations of the four pesticides that did not increase sister chromatid exchanges significantly when tested alone, were positive for sister chromatid exchange induction when tested as a mixture. The experiments show that sub-threshold doses of pesticides may increase sister chromatid exchanges when present in a mixture.
[Dolara P et al; Mutat Res 283 (2): 113-8 (1992)]**PEER REVIEWED**

/Pyrethroid/ detoxification ... important in flies, may be delayed by the addition of synergists ... organophosphates or carbamates ... to guarantee a lethal effect. ... /Pyrethroid/
[Buchel KH (ed); Chemistry of Pesticides p.19 (1983)]**PEER REVIEWED**

Piperonyl butoxide potentiates /insecticidal activity/ of pyrethrins by inhibiting the hydrolytic enzymes responsible for pyrethrins' metabolism in arthropods. When piperonyl butoxide is combined with pyrethrins, the insecticidal activity of the latter drug is increased 2-12 times /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements). 3203]**PEER REVIEWED**

At dietary level of 1000 ppm pyrethrins & 10000 ppm piperonyl butoxide ... /enlargement, margination, & cytoplasmic inclusions in liver cells of rats/ were well developed in only 8 days, but ... were not maximal. Changes were proportional to dosage & similar to those produced by DDT. Effects of the 2 ... were additive. /Pyrethrins/
[Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982. 78]**PEER REVIEWED**

Pharmacology:

Therapeutic Uses:

Pyrethrins with piperonyl butoxide are used for topical treatment of pediculosis(lice infestations). Combinations of pyrethrins with piperonyl butoxide are not effective for treatment of scabies (mite infestations). Although there are no well-controlled comparative studies, many clinicians consider 1% lindane to be pediculicide of choice. However, some clinicians recommend use of pyrethrins with piperonyl butoxide, esp in infants, young children, & pregnant or lactating women ... . If used correctly, 1-3 treatments ... are usually 100% effective ... Oil based (eg, petroleum distillate) combinations ... produce the quickest results. ... For treatment of pediculosis, enough gel, shampoo, or solution ... should be applied to cover affected hair & adjacent areas ... After 10 min, hair is ... washed thoroughly ... treatment should be repeated after 7-10 days to kill any newly hatched lice. /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements). 3203]**PEER REVIEWED**

Interactions:

Deltamethrin was hydrolysed in vitro by esterases in blood, brain, kidney, liver, and stomach preparations of mice. Pretreatment of mice with the oxidase inhibitor, pipronyl butoxide (PBO), or the esterase inhibitor, S,S,S-tributylphosphorotrithoiate (DEF), delayed metabolism of intraperitoneally administered deltamethrin. PBO or DEF made mice more sensitive to deltamethrin.
[WHO; Environmental Health Criteria 97: Deltamethrin p.81 (1990)]**PEER REVIEWED**

Plasma esterases, in addition to hepatic esterases, play a role in the metabolism of deltamethrin in mammals and cause its rapid detoxification by the oral route. In a potentiation study, a range of esterase inhibitors, consisting mainly of organophosphorus insecticides, was given to male rats in oral doses that inhibited 50% of the plasma cholinesterase. After 15 min, or 2 or 24 hr, an oral LD50 dose of deltamethrin EC formulation was given which showed potentiation with azinphos ethyl, omethoate, and dichlorvos. It appears that users must handle deltamethrin in these combinations very carefully because of their high toxicity. Acephate, monocrotophos, phosphamidon, parathion methyl, and the 2 controls did not act as potentiators.
[WHO; Environmental Health Criteria 97: Deltamethrin p.81 (1990)]**PEER REVIEWED**

The effect of deltamethrin pretreatment on the pharmacokinetics and metabolism of antipyrine was studied in male rats. The total plasma clearance of antipyrine was significantly decreased by deltamethrin pretreatment (20 mg/kg and 40 mg/kg daily for 6 days prior to antipyrine administration), while the elimination half-life at beta phase, the area under the concentration-time curve and the mean residence time of antipyrine were significantly increased. The magnitude of the observed changes was dose dependent. The urinary excretion of norantipyrine, 4-hydroxyantipyrine and 3-hydroxymethylantipyrine was decreased by 39%, 32% and 26%, respectively (p <0.001) in the presence of deltamethrin. In addition, the rate constants for formation of each of these metabolites were significantly decreased by an average of approximatel 71%. These results suggest that deltamethrin is capable of inhibiting oxidative metabolism, a finding which could be of clinical and toxicological significance.
[Anadon A et al; Arch Toxicol 65 (2): 156-9 (1991)]**PEER REVIEWED**

The effect of deltamethrin pretreatment on the pharmacokinetics and metabolism of antipyrine was studied in male rats. The total plasma clearance of antipyrine was significantly decreased by deltamethrin pretreatment (20 mg/kg and 40 mg/kg daily for 6 days prior to antipyrine administration), while the elimination half-life at beta phase, the area under the concentration-time curve and the mean residence time of antipyrine were significantly increased. The magnitude of the observed changes was dose dependent. The urinary excretion of norantipyrine, 4-hydroxyantipyrine and 3-hydroxymethylantipyrine was decreased by 39%, 32% and 26%, respectively (p < 0.001) in the presence of deltamethrin. In addition, the rate constants for formation of each of these metabolites were significantly decreased by an average of approximately 71%. These results suggest that deltamethrin is capable of inhibiting oxidative metabolism, a finding which could be of clinical and toxicological significance.
[Anadon A et al; Arch Toxicol 65 (2): 156-9 (1991)]**PEER REVIEWED**

There is a potential hazard in mixed intoxications by pyrethroids and organophosphate insecticides, due to the fact that low toxicity of pyrethroids on mammals is chiefly due to quick cleavage of molecule by esterases, which can be thwarted by esterase inhibitors. We have developed a method in order to measure the duration and the intensity of potentiation of deltamethrin by a variety of organophosphate compounds. It was demonstrated that some of them (azinphos, dichlorvos, dimethoate, fenitrothion, omethoate) induce an increase of toxicity of deltamethrin. But, the total toxicity of association of Deltamethrin with Dimethoate, Fenitrothion, is weak, and does not prohibit their use. Others (methyl-parathion, acephate, phosphamidon, monocrotophos) have no such effects, even if they have a very high intrinsic toxicity. Cholinesterase inhibitors of the carbamate group are ineffective. It is suggested that the potentiation is mainly in relation with the kinetic of esterase inhibition, which is different, and specific to each organophosphate compound. So, it is essential that a specific toxicological measurement must be performed with any different insecticide, in order to anticipate the danger of a mixed intoxication by pyrethroids and organophosphates.
[Audegond L et al; J Toxicol Clin Exp 9 (3): 163-76 (1989)]**PEER REVIEWED**

Dimethoate and omethoate, two common organophosphorus insecticides, induced a dose related increase in the frequency of sister chromatid exchanges in human lymphocytes in vitro (p of the regression lines less than 1). Two other common pesticides, the pyrethroid insecticide deltamethrin and the systemic fungicide benomyl, induced a modest increase in sister chromatid exchanges which bordered on statistical significance (p = 0.053 and 0.055, respectively). Mixtures of the four pesticides at total concentrations of 41.5 and 83 ug/ml (composed of 43% dimethoate, 43% omethoate, 12% deltamethrin and 1.2% benomyl) induced a dose-dependent increase in sister chromatid exchanges (p <0.01). The effects of these mixtures of pesticides were variable using lymphocytes from different individuals, although these differences did not attain statistical significance. Moreover, low concentrations of the four pesticides that did not increase sister chromatid exchanges significantly when tested alone, were positive for sister chromatid exchange induction when tested as a mixture. The experiments show that sub-threshold doses of pesticides may increase sister chromatid exchanges when present in a mixture.
[Dolara P et al; Mutat Res 283 (2): 113-8 (1992)]**PEER REVIEWED**

/Pyrethroid/ detoxification ... important in flies, may be delayed by the addition of synergists ... organophosphates or carbamates ... to guarantee a lethal effect. ... /Pyrethroid/
[Buchel KH (ed); Chemistry of Pesticides p.19 (1983)]**PEER REVIEWED**

Piperonyl butoxide potentiates /insecticidal activity/ of pyrethrins by inhibiting the hydrolytic enzymes responsible for pyrethrins' metabolism in arthropods. When piperonyl butoxide is combined with pyrethrins, the insecticidal activity of the latter drug is increased 2-12 times /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements). 3203]**PEER REVIEWED**

At dietary level of 1000 ppm pyrethrins & 10000 ppm piperonyl butoxide ... /enlargement, margination, & cytoplasmic inclusions in liver cells of rats/ were well developed in only 8 days, but ... were not maximal. Changes were proportional to dosage & similar to those produced by DDT. Effects of the 2 ... were additive. /Pyrethrins/
[Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982. 78]**PEER REVIEWED**

Environmental Fate & Exposure:

Environmental Fate/Exposure Summary:

Deltamethrin's production and use as an insecticide will result in its release to the environment. If released to air, a vapor pressure of 1.5X10-8 mm Hg at 25 deg C indicates deltamethrin will exist solely in the particulate phase in the ambient atmosphere. Particulate-phase deltamethrin will be removed from the atmosphere by wet and dry deposition. If released to soil, deltamethrin is expected to have no mobility based upon a Koc range from 46,000 to 1,630,000. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 5X10-6 atm-cu m/mole. However, adsorption to soil is expected to attenuate volatilization. Deltamethrin is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation is expected to be an important environmental fate process for deltamethrin, the half-life of deltamethrin within soil has been shown to range from several weeks to over a 100 days. If released into water, deltamethrin is expected to adsorb to suspended solids and sediment based upon its experimental Koc range. Deltamethrin was found to have a water column disappearance half-life of 2-4 hrs. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 30 and 500 hours, respectively. However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The volatilization from a model pond is about 7 years when adsorption is considered. An estimated BCF of 270 suggests the potential for bioconcentration in aquatic organisms is high. Estimated hydrolysis half-lives of 36 and 3.6 years were estimated for pH values of 7 and 8, respectively. Occupational exposure to deltamethrin may occur through inhalation of dust particles and dermal contact with this compound at workplaces where deltamethrin is produced or used. Monitoring data indicate that the general population may be exposed to deltamethrin via inhalation of ambient air, ingestion of food and dermal contact with this compound. (SRC)
**PEER REVIEWED**

Probable Routes of Human Exposure:

Dermal exposure of deltamethrin to a pilot applying the insecticide while flying an ultra-light aircraft was 10.8 ug/hr(1); a ground-based flagman on duty during the aerial spraying received a dermal exposure of 25 ug/hr(1); dermal exposure to workers manually spraying deltamethrin was 2.8-42.2 mg/hr(1); the 1000-fold exposure difference between hand-held applicators and aerial applicators was due, in part, to work practices of the workers(1). Inhalation exposure of workers involved in spray applications of deltamethrin in greenhouses was measured as 5.2 ug/cu m at the time of spraying and 0.008 ug/cu m 30 min after spraying(2); dermal exposures (chest, back, arms, forearms, hands, legs) ranged from 0.21 to 10.5 ug/100 cu cm(2). Workers packaging deltamethrin in a small importing factory in China were reported to have been exposed to airborne levels of 0.2-1.2 ug/cu m, with resulting skin contact(3). Air concns of deltamethrin at the breathing zone of workers spraying deltamethrin insecticide on cotton was 0.02-0.11 ug/cu m(4); dermal exposure ranged from 0.14 to 1.48 ug/cu cm on forearms, hands, legs and feet(4). Occupational exposure to deltamethrin may occur through inhalation of dust particles and dermal contact with this compound at workplaces where deltamethrin is produced or used. Monitoring data indicate that the general population may be exposed to deltamethrin via inhalation of ambient air, ingestion of food and dermal contact with this compound(SRC).
[(1) Yoshida K et al; J Environ Sci Health B25: 151-67 (1990) (2) Mestres R et al; Bull Environ Contam Toxicol 35: 750-6 (1985) (3) IARC; IARC Monographs on the Evaluation of Carcinogen Risks to Humans. Lyon, France: World Health Organization 53: 251-66 (1991) (4) Zhang Z et al; Brit J Industr Med 48: 82-6 (1991)]**PEER REVIEWED**

Body Burden:

Urine concns of deltamethrin of workers spraying deltamethrin insecticide on cotton was 0.01-1.79 ug/collection interval (3-12 hr) for a period up to 72 hr after spraying(1).
[(1) Zhang Z et al; Brit J Industr Med 48: 82-6 (1991)]**PEER REVIEWED**

Artificial Pollution Sources:

Deltamethrin's production and use as an insecticide(1) is expected to result in its direct release to the environment(SRC).
[(1) Budavari S; The Merck Index. 12th ed. Whitehouse Station, NJ: Merck & Co Inc p. 648 (1996)]**PEER REVIEWED**

Environmental Fate:

TERRESTRIAL FATE: Based on a classification scheme(1), an experimental Koc range from 46,000 to 1,630,000(2) indicates that deltamethrin is expected to be immobile in soil(SRC). Volatilization of deltamethrin from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5X10-6 atm-cu m/mole(SRC), determined from its vapor pressure, 1.5X10-8(3), and water solubility, 2X10-3 mg/l(3). However, adsorption to soil is expected to attenuate volatilization(SRC). Deltamethrin is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). Biodegradation is expected to be an important environmental fate process for deltamethrin. Laboratory and field studies measured deltamethrin soil half-lives of 4.9-6.9 weeks in a sandy clay loam soil(4).
[(1) Swann RL et al; Res Rev 85: 17-28 (1983) (2) Tomlin CDS, ed; The Pesticide Manual. 11th ed. Farnham, UK: British Crop Prot Council, Crop Prot Pub p. 1248 (1997) (3) Worthing CR, Walker SB, eds; The Pesticide Manual-World Compendium. 8th ed. Thornton Heath, UK: The British Crop Prot Council p. 234 (1987) (4) Hill BD; J Environ Sci Health B18: 691-703 (1983)]**PEER REVIEWED**

AQUATIC FATE: Based on a classification scheme(1), an experimental Koc range from 46,000 to 1,630,000(2), indicates that deltamethrin is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 5X10-6 atm-cu m/mole(SRC), determined from its vapor pressure, 1.5X10-8(4), and water solubility, 2X10-3 mg/l(4). According to a classification scheme(5), an estimated BCF of 270(SRC), from its log Kow of 6.2(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is high(SRC). A field study involving 4 prairie ponds in Saskatchewan, Canada and aerial spraying found deltamethrin half-lives of 0.6-5 hr in the surface-film formed by the spraying and an avg half-life of 14-hr in the subsurface water(8); degradation products included a cyclopropyl acid derivative and phenoxybenzoic acid(8).
[(1) Swann RL et al; Res Rev 85: 17-28 (1983) (2) Tomlin CDS, ed; The Pesticide Manual. 11th ed. Farnham, UK: British Crop Prot Council, Crop Prot Pub p. 1248 (1997) (3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 4-9, 15-1 to 15-29 (1990) (4) Worthing CR, Walker SB eds; The Pesticide Manual - World Compendium. 8th ed. Thornton Heath, UK: The British Crop Prot Council p. 234 (1987) (5) Franke C et al; Chemosphere 29: 1501-14 (1994) (6) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Socp. 175 (1995) (7) Meylan WM et al; Environ Toxicol Chem 18: 664-72 (1999) (8) Muir DCG et al; Environ Toxicol Chem 11: 581-91 (1992)]**PEER REVIEWED**

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), deltamethrin, which has a vapor pressure of 1.5X10-8 mm Hg at 25 deg C(2) will exist solely in the particulate phase in the ambient atmosphere. Particulate-phase deltamethrin may be removed from the air by wet and dry deposition(SRC).
[(1) Bidleman TF; Environ Sci Technol 22: 361-367 (1988) (2) Worthing CR, Walker SB eds; The Pesticide Manual- World Compendium. 8th ed. Thornton Heath, UK: The British Crop Prot Council p. 234 (1987)]**PEER REVIEWED**

Environmental Biodegradation:

AEROBIC: Laboratory and field studies measured deltamethrin soil half-lives of 4.9-6.9 weeks in a sandy clay loam soil(1). A German laboratory study measured a soil half-life of 110 days(2). When applied to soil (in both field and laboratory tests) in high water volumes with a pipet, deltamethrin exhibited initial half-lives of about 5-8 weeks(3); when applied as a spray, disappearance was roughly 2-4 times faster(3). A half-life of 72 days was measured in an organic soil (under laboratory conditions) over a 180-day observation period(4). Half-lives of 35 and 60 days have been reported for German sandy soil and sandy loam soil, respectively(5). Half-lives of deltamethrin sprayed on forage, litter, alfalfa and sweet peppers were 5.9, 17, 3.4 and 1.5-2.0 days, respectively(6-8). Less than 50% deltamethrin remained on cotton and beans after 4-5 days outdoors(9). In soil degradation studies using a mineral and an organic soil, 26-48% of applied deltamethrin disappeared after an 8-week incubation period(10); in sterile soil controls, only 0-3% of applied deltamethrin disappeared suggesting that the disappearance was primarily due to biotic processes(10). In a biodegradation study using deltamethrin as a sole source of carbon and energy and bacterial isolates from soil as inoculum, 35.7-44.4% of initial deltamethrin metabolized in one week and 59.7-72.5% in two weeks(11); in the absence of bacterial isolates, only 3-10% of the deltamethrin was metabolized(11). Deltamethrin's half-life was reported to be 23 days in the Vemmenhog catchment located in Southern Sweden(12). Activated sludge collected from a purification plant in the city of Rome, Italy was used to biodegrade nine pesticides(13). The biodegradation of deltamethrin was evaluated after 3, 6, and 9 hours: deltamethrin was 51.4% degraded after 3 hours, 59.8% degraded after 6 hours and 63.4% degraded after 9 hours(13). Deltamethrin applied to alfalfa at a concentration of 14 g/ha had a DT50 of 5.1-7.7 days and a DT90 of 24-26 days(14). Based on a minimum detectable level of 0.03 ppm dry weight basis, it was estimated that 45-48 days would be required to reduce the concentration of deltamethrin to non-detectable levels(14).
[(1) Hill BD; J Environ Sci Health B18: 691-703 (1983) (2) Bahadir M et al; Chemosphere 16: 1311-7 (1987) (3) Hill BD, Schaalje GB; J Agric Food Chem 33: 1001-6 (1985) (4) Zhang LZ et al; J Agric Food Chem 32: 1207-11 (1984) (5) IARC; IARC Monographs on the Evaluation of Carcinogen Risks to Humans. Lyon, France: World Health Organization 53: 251-66 (1991) (6) Hill BD, Johnson DL; J Agric Food Chem 35: 373-8 (1987) (7) Hill BD et al; J Agric Food Chem 37: 1150-3 (1989) (8) Awasthi MD; Indian J Plant Prot 18: 277-80 (1990) (9) Cole LM et al; J Agric Food Chem 30: 916-20 (1982) (10) Chapman RA et al; Bull Environ Contam Toxicol 26: 513-19 (1981) (11) Khan SU et al; J Agric Food Chem 36: 636-8 (1988) (12) Kreuger J et al; Bull Environ Contam Toxicol 62: 55-62 (1999) (13) Leoni V et al; The Science of the Total Environment 123/124: 279-289 (1992) (14) Hill BD et al; J Agric Food Chem 40: 2493-2496 (1992)]**PEER REVIEWED**

Environmental Abiotic Degradation:

A base-catalyzed second-order hydrolysis rate constant of 6.1X10-3 L/mole-sec(SRC) was estimated using a structure estimation method(1). This corresponds to half-lives of 36 and 3.6 years at pH values of 7 and 8, respectively(1). Deltamethrin was observed to undergo direct photolysis when hexane, acetonitrile-water, or water solutions were exposed to UV radiation >295 nm(2). In aqueous solution, the photolysis rate increased rapidly when a 2% acetone photosensitizer was added(2). Photolysis rates were slower in water than in hexane or acetonitrile-water(2). The photodegradation reaction went through racemization at the alpha position in the alcohol moiety, ester cleavage and reductive bromination(2). When cotton strips impregnated with deltamethrin were exposed to a UV lamp (simulating midday natural sunlight) for a 24-hr period, 31-99% of the initial deltamethrin degraded(3). The fastest degradation rates occurred on white fabric while the slowest rates occurred on black fabric(3); addition of 2,4-dihydroxybenzophenone (a UV absorber) reduced photodegradation rates(3). Deltamethrin, impregnated on cloth, has been observed to degrade rapidly when exposed to sunlight(4). The photodegradation half-life of deltamethrin in distilled and natural water solutions exposed to sunlight was found to range from 1 to less than 5 days(5). Deltamethrin also photodegraded as thin-films or when sprayed on potato leaves exposed to sunlight(5). Deltamethrin disappears much more rapidly from soil environments from surface application routes as compared to application routes that wash it into or incorporate it into the soil(6) which indicates the importance of photodegradation and volatilization(SRC). A field study involving 4 prairie ponds in Saskatchewan, Canada and aerial spraying found deltamethrin half-lives of 0.6-5 hr in the surface-film formed by the spraying and an avg half-life of 14-hr in the subsurface water(7); degradation products included a cyclopropyl acid derivative and phenoxybenzoic acid(7). In a field study using two small ponds and subsurface injections of deltamethrin, a water column disappearance half-life of 2-4 hr was observed with rapid partitioning to sediment and suspended solids (disappearance included transport, degradation and partitioning)(8); the disappearance half-life in the sediment was 5-14 days(8); major degradation products were cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-carboxylic acid and 3-phenoxybenzoic acid(8).
[(1) Mill T et al; Environmental Fate and Exposure Studies Development of a PC-SAR for Hydrolysis: Esters, Alkyl Halides and Epoxides. EPA Contract No. 68-02-4254. Menlo Park, CA: SRI International (1987) (2) Qian J et al; Huanjing Kexue Xuebao 8: 275-85 (1988) (3) Hussain M, Perschke H; Chemosphere 22: 677-84 (1991) (4) Torr SJ; Bull Entomol Res 75: 451-8 (1985) (5) Maguire RJ; J Agric Food Chem 38: 1613-7 (1990) (6) Hill BD, Schaalje GB; J Agric Food Chem 33: 1001-6 (1985) (7) Muir DCG et al; Environ Toxicol Chem 581-91 (1992) (8) Muir DCG et al; J Agric Food Chem 33: 603-9 (1985)]**PEER REVIEWED**

Environmental Bioconcentration:

In a static system for a 24-hr exposure period, deltamethrin BCFs of about 200 to 1300 were measured for Daphnia magnus(1); observed BCFs decreased with increases in dissolved organic carbon(1). BCF values of 39-303 were measured in larvae of the midge Chronomus tentans in sand, silt or clay sediment water systems(2). In a pond study using radio-labelled C-14 deltamethrin, fathead minnows (Pimephales promelas) accumulated levels of extractable radioactivity 248-907 times higher than levels in the water at 24-hr after exposure although the nature of the radioactive compounds was not provided(3). According to a classification scheme(4), these BCF values suggest that the potential for bioconcentration in aquatic organisms is high(SRC).
[(1) Day KE; Environ Toxicol Chem 10: 91-101 (1991) (2) Muir DCG et al; Environ Toxicol Chem 4: 51-61 (1985) (3) Muir DCG et al; J Agric Food Chem 33: 603-9 (1985) (4) Franke C et al; Chemosphere 29: 1501-14 (1994)]**PEER REVIEWED**

Soil Adsorption/Mobility:

The Koc of deltamethrin has been found to range from 46,000 to 1,630,000(1). According to a classification scheme(2), this Koc range suggests that deltamethrin is expected to be immobile in soil. The mobility of deltamethrin in soil was studied in soil column experiments and by soil thin-layer chromatography (TLC) using a Hagerstown silty clay, a silty clay loam and a Tifton loamy sand(3); deltamethrin was found to be immobile in all soils studied(3). Two hours after dissolved organic carbon (DOC) was added to water solutions of deltamethrin, about 20% of the deltamethrin was sorbed to the DOC(4); after 24 hr, nearly 81% was sorbed to the DOC(4). Laboratory studies have shown that deltamethrin applied to water surfaces or to subsurface water will partition rapidly from the water column to suspended solids, sediment, and plants(5,6).
[(1) Tomlin CDS, ed; The Pesticide Manual. 11th ed. Farnham, UK: British Crop Prot Council, Crop Prot Pub p. 1248 (1997) (2) Swann RL et al; Res Rev 85: 17-28 (1983) (3) Kaufman DD et al; J Agric Food Chem 29: 239-45 (1981) (4) Day KE; Environ Toxicol Chem 10: 91-101 (1991) (5) Maguire RJ et al; J Agric Food Chem 37: 1153-9 (1989) (6) Muir DCG et al; J Agric Food Chem 33: 603-9 (1985)]**PEER REVIEWED**

Volatilization from Water/Soil:

The Henry's Law constant for deltamethrin is estimated as 5X10-6 atm-cu m/mole(SRC) determined from its vapor pressure, 1.5X10-8 mm Hg(1), and water solubility, 2X10-3 mg/l(1). This Henry's Law constant indicates that deltamethrin is expected to volatilize from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 30 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 500 hours(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The volatilization from a model pond is about 7 years(4) when adsorption is considered. Deltamethrin's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Deltamethrin is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.5X10-8 mm Hg(1). When insecticidal formulations of deltamethrin are sprayed on water, they form a thin microlayer on the water's surface(5-8); the thickness of the surface microlayer depends upon the formulation and amount of spray; since deltamethrin is relatively insoluble in water, its transport into subsurface waters can be slow, which has been demonstrated by laboratory and field studies(5-8); laboratory tests have shown that deltamethrin volatilizes rapidly from a surface microlayer with half-lives of several hours or faster(5,6); the results of field and laboratory tests indicate that volatilization may be the major route for disappearance of deltamethrin sprayed on water surfaces(5,6). Laboratory tests were conducted to determine volatilization losses of deltamethrin sprayed on plant and soil surfaces(9); under the conditions of the experiment, evaporative losses from lettuce, kohlrabi, green beans and summer wheat ranged from 12-71% over a 24-hr period(9); evaporative loss from soil was 24% in 24-hr(9).
[(1) Worthing CR, Walker SB eds; The Pesticide Manual- World Compendium. 8th ed. Thornton Heath, UK: The British Crop Prot Council p. 234 (1987) (2) Tomlin CDS, ed; The Pesticide Manual. 11th ed. Farnham, UK: British Crop Prot Council, Crop Prot Pub p. 1248 (1997) (3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15- 29 (1990) (4) US EPA; EXAMS II Computer Simulation (1987) (5) Maguire RJ; J Agric Food Chem 39: 1674-8 (1991) (6) Maguire RJ et al; J Agric Food Chem 37: 1153-9 (1989) (7) Muir DCG et al; J Agric Food Chem 33: 603-9 (1985) (8) Muir DCG et al; Environ Toxicol Chem 11: 581-91 (1992) (9) Boehncke A et al; Chemosphere 21: 1109-24 (1990)]**PEER REVIEWED**

Effluent Concentrations:

In one aerial deposition study involving spray application from an airplane, peak deposition to the ground was 0.5-1.2 ng/cu cm(1). A site 4 km from the spray area received ground depositions as high as 0.2 ng/cu cm, although most areas outside the spray area received insignificant deposition(1).
[(1) Johnstone DR et al; Atmos Environ 21: 2311-21 (1987)]**PEER REVIEWED**

Sediment/Soil Concentrations:

Deltamethrin was applied at an amount of less than 1 kg per year in 1990 and 1991 in the Vemmenhog catchment in Southern Sweden(1). During that same time period deltamethrin was detected in sediment samples of the Vemmenhog catchment at an average concentration of 20 ug/kg dry weight(1).
[(1) Kreuger J et al; Bull Environ Contam Toxicol 62: 55-62 (1999)]**PEER REVIEWED**

Food Survey Values:

598 samples of food were analyzed as part of the Canadian National Surveillance Program in 1984-1989(1); 3 samples contained deltamethrin residues (2/25 samples of apples and 1/21 of strawberries) at levels of 0.004-0.006 mg/kg(1). Deltamethrin concentrations were measured by means of capillary gas chromatography using extraction with ethyl acetate and dichloromethane from vegetable and fruit samples(2). Deltamethrin concentrations ranged from 69.4 to 98.6 ppm for those samples measured with ethyl acetate extraction(2), while concentrations ranged from 64.1 to 88.5 ppm for those samples measured with dichloromethane extraction(2). Fruit and vegetable samples in Pakistan were tested for pesticide residues by means of gas and thin-layer chromatography(3). Deltramethrin was detected at the following concentrations: cucumber, 0.13 mg/kg; bitter gourd, 1.12-1.7 mg/kg(3). Deltamethrin residues were detected at concentrations ranging from non-detectable to 0.23 mg/kg in laboratory pressed olive oil samples in Italy(4).
[(1) IARC; IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Lyon, France: World Health Organization 53: 251-66 (1991) (2) Nakamura Y et al; J Agric Food Chem 42: 2508-2518 (1994) (3) Masud SZ, Hasan N; pp. 269-279 in Environ Toxicol Assess, Richardson M, ed., London, England: Taylor and Francis (1995) (4) Lentza-Rizos, Avramides EJ; Rev Environ Contam Toxicol 141: 111-134 (1995)]**PEER REVIEWED**

Other Environmental Concentrations:

A study was conducted to determine the ability of laundry practices used by farm families to remove pesticides from clothing(1). After one wash, 2-18% of initial deltamethrin remained on fabrics(1); after two washes, 1-10% of initial deltamethrin remained on fabrics(1). Cotton strips were coated with deltamethrin and then washed in deionized water for one hr(2). After 4 washings, only 37.7% of initial deltamethrin was removed from the cotton(2). Impregnating the cotton with various paraffin wax and oils (corn, linseed, silicone) before coating with deltamethrin resulted in lower percentages removed when washed (9.9-29.2% removal)(2).
[(1) Rigakis KB et al; Agric Forestry Bull 10: 24-6 (1987) (2) Hussain M, Perschke H; Chemosphere 22: 677-84 (1991)]**PEER REVIEWED**

Environmental Standards & Regulations:

FIFRA Requirements:

Tolerances are established for the combined residues of the pesticide chemical deltamethrin [(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid (S)-alpha-cyano-3-phenoxybenzyl ester and its major metabolites, trans deltamethrin [(S)-alpha-cynao-m-phenoxybenzyl(1,R,3S)-3-(2,2-dibromovinyl)-2,2-dimethylcyclop ropanecarboxylate] and alpha-R-deltamethrin [(R)-alpha-cyano-m-phenoxybenzyl-(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclop ropanecarboxylate] in or on the following agricultural commodities: cottonseed; cottonseed oil; tomatoes; and tomato (products) concentrated.
[40 CFR 180.435(a)(1) (7/1/2000)]**PEER REVIEWED**

A tolerance is established for residues of the insecticide deltamethrin (1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid (S)-alpha-cyano-3-phenoxybenzyl ester and its major metabolites, trans deltamethrin (S)-alpha-cynao-m-phenoxybenzyl(1,R,3S)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopr opanecarboxylate and alpha-R-deltamethrin [(R)-alpha-cyano-m-phenoxybenzyl-(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclop ropanecarboxylate] as follows: in or on all food/feed items (other than those covered by a higher tolerance as a result of use on growing crops) in food/feed handling establishments.
[40 CFR 180.435(a)(2)(i) (7/1/2000)]**PEER REVIEWED**

Acceptable Daily Intakes:

FAO/WHO ADI: 0.01 mg/kg
[FAO/WHO; Pesticide Residues in Food - 1992. Evaluations Part 1 - Residues p.869 Plant Prod Protection Paper 118 (1992)]**PEER REVIEWED**

Allowable Tolerances:

Tolerances are established for the combined residues of the pesticide chemical deltamethrin [(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid (S)-alpha-cyano-3-phenoxybenzyl ester and its major metabolites, trans deltamethrin [(S)-alpha-cynao-m-phenoxybenzyl(1,R,3S)-3-(2,2-dibromovinyl)-2,2-dimethylcyclop ropanecarboxylate] and alpha-R-deltamethrin [(R)-alpha-cyano-m-phenoxybenzyl-(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclop ropanecarboxylate] in or on the following agricultural commodities: cottonseed, 0.04 ppm; cottonseed oil, 0.2 ppm; tomatoes, 0.2 ppm; and tomato (products) concentrated, 1.0 ppm.
[40 CFR 180.435(a)(1) (7/1/2000)]**PEER REVIEWED**

A tolerance of 0.05 ppm is established for residues of the insecticide deltamethrin (1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid (S)-alpha-cyano-3-phenoxybenzyl ester and its major metabolites, trans deltamethrin (S)-alpha-cynao-m-phenoxybenzyl(1,R,3S)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopr opanecarboxylate and alpha-R-deltamethrin [(R)-alpha-cyano-m-phenoxybenzyl-(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclop ropanecarboxylate] as follows: in or on all food/feed items (other than those covered by a higher tolerance as a result of use on growing crops) in food/feed handling establishments.
[40 CFR 180.435(a)(2)(i) (7/1/2000)]**PEER REVIEWED**

Chemical/Physical Properties:

Molecular Formula:

C22-H19-Br2-N-O3
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 453]**PEER REVIEWED**

Molecular Weight:

505.21
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 488]**PEER REVIEWED**

Color/Form:

Crystals
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 488]**PEER REVIEWED**

Colorless crystals
[Brooke, L.T., D.J. Call, D.T. Geiger and C.E. Northcott (eds.). Acute Toxicities of Organic Chemicals to Fathead Minnows (Pimephales Promelas). Superior, WI: Center for LakeSuperior Environmental Studies Univ. of Wisconsin Superior, 1984.,p. A122/Aug 87]**PEER REVIEWED**

White or slightly beige powder
[Hayes WJ, Laws ER, eds; Handbook of Pesticide Toxicology V2 p.595 (1991)]**PEER REVIEWED**

Odor:

Odorless
[WHO; Environmental Health Criteria 97: Deltamethrin p.23 (1990)]**PEER REVIEWED**

Melting Point:

101-102 deg C
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997 344]**PEER REVIEWED**

Corrosivity:

Non-corrosive to metals
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Octanol/Water Partition Coefficient:

log Kow= 6.20
[Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995. 175]**PEER REVIEWED**

Solubilities:

Acetone: 500 g/l @ 20 deg C
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997 345]**PEER REVIEWED**

Sol in ethanol, acetone, dioxane.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 488]**PEER REVIEWED**

Water solubility= < 0.002 mg/l
[WHO; Environmental Health Criteria 97: Deltamethrin p.23 (1990)]**PEER REVIEWED**

Acetone (500 g/l), ethanol (15 g/l), cyclohexanone (750 g/l), dioxan (900 g/l), xylene (250 g/l), ethyl acetate.
[WHO; Environmental Health Criteria 97: Deltamethrin p.23 (1990)]**PEER REVIEWED**

Solubility; in cyclohexanone 750, dichloromethane 700, benzene 450, dimethyl sulphoxide 450, xylene 250, isopropanol 6 (all in g/l at 20 deg C)
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997 345]**PEER REVIEWED**

In water, 0.002 mg/l @ 25 deg C
[Worthing, C.R. and S.B. Walker (eds.). The Pesticide Manual - A World Compendium. 8th ed. Thornton Heath, UK: The British Crop Protection Council, 1987. 234]**PEER REVIEWED**

Spectral Properties:

Specific rotation: +61 deg (40 g/l benzene)
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 287]**PEER REVIEWED**

Vapor Pressure:

1.5X10-8 mm Hg @ 25 deg C
[Worthing, C.R. and S.B. Walker (eds.). The Pesticide Manual - A World Compendium. 8th ed. Thornton Heath, UK: The British Crop Protection Council, 1987. 234]**PEER REVIEWED**

Other Chemical/Physical Properties:

The technical material produced industrially ... contains greater than or equal to 98% deltamethrin m/m (proportion by mass) and is a colorless crystalline powder. /Technical deltamethrin/
[Worthing, C.R. and S.B. Walker (eds.). The Pesticide Manual - A World Compendium. 8th ed. Thornton Heath, UK: The British Crop Protection Council, 1987. 234]**PEER REVIEWED**

Chemical Safety & Handling:

Skin, Eye and Respiratory Irritations:

The chief effect from exposure ... is skin rash particularly on moist areas of the skin. ... May irritate the eyes.
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 1]**PEER REVIEWED**

Fire Fighting Procedures:

Use carbon dioxide, foam, or dry chemical /on fires involving pyrethroids/. /Pyrethrum/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 2]**PEER REVIEWED**

Fire-fighting: Self-contained breathing apparatus with a full facepiece operated in pressure-demand or other positive-pressure mode. /Pyrethrum/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 5]**PEER REVIEWED**

Hazardous Reactivities & Incompatibilities:

Incompatibility: Strong oxidizers. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

... Incompatible with lime & ordinary soaps because acids & alkalies speed up processes of hydrolysis. /Pyrethrins/
[Farm Chemicals Handbook 1986. Willoughby, Ohio: Meister Publishing Co., 1986.,p. C-198]**PEER REVIEWED**

Hazardous Decomposition:

Half life of 2.5 days (pH 9, 25 deg C)
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 287]**PEER REVIEWED**

When heated to decomp it emits toxic fumes of /hydrogen bromide, hydrogen cyanide, nitrogen oxides/.
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 993]**PEER REVIEWED**

Protective Equipment & Clothing:

Employees should be provided with and required to use dust- and splash-proof safety goggles where /pyrethroids/ ... may contact the eyes. /Pyrethroids/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 3]**PEER REVIEWED**

Employees should be provided with and be required to use impervious clothing, gloves, and face shields (eight-inch minimum). /Pyrethroids/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 2]**PEER REVIEWED**

Wear appropriate equipment to prevent: Repeated or prolonged skin contact. /Pyrethrum and pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Wear eye protection to prevent: Reasonable probability of eye contact. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Recommendations for respirator selection. Max concn for use: 50 mg/cu m: Respirator Classes: Any chemical cartridge respirator with organic vapor cartridge(s) in combination with a dust, mist, and fume filter. May require eye protection. Any supplied-air respirator. May require eye protection. Any self-contained breathing apparatus. May require eye protection. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Recommendations for respirator selection. Max concn for use: 125 mg/cu m: Respirator Classes: Any supplied-air respirator operated in a continuous flow mode. May require eye protection. Any powered, air-purifying respirator with organic vapor cartridge(s) in combination with a dust, mist, and fume filter. May require eye protection. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Recommendations for respirator selection. Max concn for use: 250 mg/cu m: Respirator Classes: Any chemical cartridge respirator with a full facepiece and organic vapor cartridge(s) in combination with a high-efficiency particulate filter. Any self-contained breathing apparatus with a full facepiece. Any supplied-air respirator with a full facepiece. Any powered, air-purifying respirator with a tight-fitting facepiece and organic vapor cartridge(s) in combination with a high-efficiency particulate filter. May require eye protection. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Recommendations for respirator selection. Max concn for use: 5,000 mg/cu m: Respirator Class: Any supplied-air respirator with a full facepiece and operated in a pressure-demand or other positive pressure mode. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Recommendations for respirator selection. Condition: Emergency or planned entry into unknown concn or IDLH conditions: Respirator Classes: Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive pressure mode. Any supplied-air respirator with a full face piece and operated in pressure-demand or other positive pressure mode in combination with an auxiliary self-contained breathing apparatus operated in pressure-demand or other positive pressure mode. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Recommendations for respirator selection. Condition: Escape from suddenly occurring respiratory hazards: Respirator Classes: Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having a high-efficiency particulate filter. Any appropriate escape-type, self-contained breathing apparatus. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Preventive Measures:

Skin that becomes contaminated with /pyrethrum/ should be promptly washed or showered with soap or mild detergent and water. /Pyrethrum/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 3]**PEER REVIEWED**

Clothing contaminated with /pyrethrum/ should be placed in closed containers for storage until provision is made for the removal of /pyrethrum/ from the clothing. /Pyrethrum/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 2]**PEER REVIEWED**

Respirators may be used when engineering and work practice controls are not technically feasible, when such controls are in the process of being installed, or when they fail or need to be supplemented. Respirators may also be used for operations which require entry into tanks or closed vessels, and in emergency situations. /Pyrethrum/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 2]**PEER REVIEWED**

Employees who handle /pyrethrum/ ... should wash their hands thoroughly with soap or mild detergent and water before eating, smoking, or using toilet facilities. /Pyrethrum/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981. 3]**PEER REVIEWED**

Avoid contact with skin. Keep out of any body of water. Do not contaminate water by cleaning of equipment or disposal of waste. Do not reuse empty container. Destroy it by perforating or crushing. /Pyrethrum/
[Farm Chemicals Handbook 1986. Willoughby, Ohio: Meister Publishing Co., 1986.,p. C-198]**PEER REVIEWED**

Contact lenses should not be worn when working with this chemical. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Workers should wash: Promptly when skin becomes contaminated. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Work clothing should be changed daily: If it is reasonably probable that the clothing may be contaminated. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

Remove clothing: Promptly if it is non-impervious clothing that becomes contaminated. /Pyrethrins/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS(NIOSH) Publication No. 90-117. Washington, DC: U.S. Government Printing Office, June 1990 190]**PEER REVIEWED**

If /pyrethrins/ are not involved in a fire: keep /pyrethrins/ out of water sources and sewers. Build dikes to contain flow as necessary. /Pyrethrins/
[Bureau of Explosives; Emergency Handling of Haz Matl in Surface Trans p.434 (1981)]**PEER REVIEWED**

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
**PEER REVIEWED**

Stability/Shelf Life:

Extremely stable on exposure to air. Stable < or = 190 deg C. Under UV irradiation & in sunlight, a cis-trans isomerization, splitting of the ester bond, & loss of bromine occur. More stable in acidic media than in alkaline media.
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 287]**PEER REVIEWED**

Pyrethrins ... /are/ stable for long periods in water-based aerosols where ... emulsifiers give neutral water systems. /Pyrethrins/
[Farm Chemicals Handbook 1986. Willoughby, Ohio: Meister Publishing Co., 1986.,p. C-198]**PEER REVIEWED**

Storage Conditions:

Pyrethrins with piperonyl butoxide topical preparations should be stored in well-closed containers at a temperature less than 40 deg C, preferably between 15-30 deg C. /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements). 3203]**PEER REVIEWED**

Cleanup Methods:

Spillages of pesticides at any stage of their storage or handling should be treated with great care. Liquid formulations may be reduced to solid phase by evaporation. Dry sweeping of solids is always hazardous: these should be removed by vacuum cleaning, or by dissolving them in water, or other solvent in the factory environment. /Pesticides/
[International Labour Office. Encyclopedia of Occupational Health and Safety. Vols. I&II. Geneva, Switzerland: International Labour Office, 1983. 1619]**PEER REVIEWED**

Disposal Methods:

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.
**PEER REVIEWED**

Incineration would be an effective disposal procedure where permitted. ... /Pyrethrin products/
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 762]**PEER REVIEWED**

Occupational Exposure Standards:

Manufacturing/Use Information:

Major Uses:

For Deltamethrin (USEPA/OPP Pesticide Code: 097805) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./
[U.S. Environmental Protection Agency/Office of Pesticide Program's Chemical Ingredients Database on Deltamethrin (52918-63-5). Available from the Database Query page at http://www.cdpr.ca.gov/docs/epa/epamenu.htm as of February 5, 2001.]**PEER REVIEWED**

Insecticide
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 488]**PEER REVIEWED**

Used in agriculture and in public health programs
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. V53 (91) 251-66]**PEER REVIEWED**

Deltamethrin is used to protect stored commodities (mainly cereals, grains, coffee beans, dry beans), in forestry, and in public health (e.g., Chagas disease control in South America, and malaria control in Central America and on the African continent). It is also used in animals facilities and against cattle infestation.
[WHO; Environmental Health Criteria 97: Deltamethrin p.85 (1990)]**PEER REVIEWED**

After an initial period when the product was mainly used on cotton, several major crops were treated with deltamethrin from 1980 to 1987. Some 85% of the total production is used for crop protection. Within this, 45% is used in cotton, 25% on fruit and vegetable crops, 20% on cereals, corn, and soybean, and the remaining 10% on miscellaneous crops.
[WHO; Environmental Health Criteria 97: Deltamethrin p.86 (1990)]**PEER REVIEWED**

Control of many species of insect, particularly Lepidoptera, Homoptera, and Coleoptera, in a very wide range of crops, including fruit, vines, olives, figs, vegetables, potatoes, ornamentals, hops, maize, oilseed rape, sunflowers, oil palms, beet cotton, coffee, cocoa, tea, rice, cereals, soya beans, lucern, tobacco, forestry, etc. Control of flying and crawling insects in households, animal houses and stored products. Control of flies, mosquitoes (adult and larvae), cockroaches, bedbugs, and other insects in public health. Also used as a wood preservative, and as an animal ectoparasiticide.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Introduced commercially in 1978 to be used against a wide range of insect pests.
[Hayes WJ, Laws ER, eds; Handbook of Pesticide Toxicology V2 p.595 (1991)]**PEER REVIEWED**

MEDICATION
**PEER REVIEWED**

Methods of Manufacturing:

Deltamethrin is ... /a/ pyrethroid composed of a single isomer of 8 stereoisomers selectively prepared by the esterification of [1R, 3R or cis]-2,2-dimethyl-3-(2,2- dibromovinyl) cyclopropanecarboxylic acid with (alpha S)- or (+)-alpha-cyano-3- phenoxybenzyl alcohol or by selective recrystallization of the racemic esters obtained by esterification of the (1R, 3R or cis)-acid with the racemic or [alpha R, alpha S, or alpha RS or + or -]-alcohol.
[WHO; Environmental Health Criteria 97: Deltamethrin p.22 (1990)]**PEER REVIEWED**

General Manufacturing Information:

Potent synthetic pyrethroid insecticide
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 453]**PEER REVIEWED**

Compatible with many insecticides and fungicides.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Contains only one of eight possible isomers.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

/Pyrethroids/ are modern synthetic insecticides similar chemically to natural pyrethrins, but modified to increase stability in the natural environment. /Pyrethroids/
[Morgan DP; Recognition and Management of Pesticide Poisonings. 4th ed. p.34 EPA 540/9-88-001. Washington, DC: U.S. Government Printing Office, March 1989]**PEER REVIEWED**

Formulations/Preparations:

USEPA/OPP Pesticide Code 097805; Trade Names: DECIS, FMC 45498, NRDC 161, Butoflin, Butox, Othrin, RU 22974, Othrine dust, striker IEC Insecticide (097805+121501).
[U.S. Environmental Protection Agency/Office of Pesticide Program's Chemical Ingredients Database on Deltamethrin (52918-63-5). Available from the Database Query page at http://www.cdpr.ca.gov/docs/epa/epamenu.htm as of February 5, 2001.]**PEER REVIEWED**

Emulsifiable concentrate; wettable powder; ULV liquid; suspension concentrate; granules; dustable powder, fogging concentrate.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Mixed formulations: (deltamethrin +) heptenophos, sulphur
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Domestic Bulgarian insecticide "Dekazol" /contains/ 0.02, 0.04, or 0.08% deltamethrin ... .
[WHO; Environmental Health Criteria 97: Deltamethrin p.87 (1990)]**PEER REVIEWED**

Laboratory Methods:

Analytic Laboratory Methods:

AOAC Method 991.03. Deltamethrin in Technical Products and Pesticide Formulation by Liquid Chromatographic method.
[Association of Official Analytical Chemists. Official Methods of Analysis. 15th ed. and Supplements. Washington, DC: Association of Analytical Chemists, 1990 66]**PEER REVIEWED**

Product analysis is by high performance liquid chromatography. Residues may be determined by gas liquid chromatography with electron capture detection.
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994. 288]**PEER REVIEWED**

Low level pyrethrin formulations are extracted with tetrahydrofuran and determined via capillary gas chromatography with electron capture detection. ... Analysis of 5 formulations gave an average standard deviation of 3.3%. /Pyrethrins/
[Stringham RW, Schutz RP; J Assoc Off Anal Chem 68 (6): 1137-9 (1985)]**PEER REVIEWED**

Special References:

Special Reports:

Mian LS, Mulla MS; Effects of Pyrethroid Insecticides on Nontarget Invertebratesin Aquatic Ecosystems. J Agric Entomol 9 (2): 73-98 (1992). This review presents data on the impacts of pyrethroid insecticides on nontarget aquatic invertebrates.

Miyamoto J; Environ Health Perspect 14: 15-28 (1976). Degradation, metabolism, and toxicity of synthetic pyrethroids.

Miyamoto J, et al; Pure Appl Chem 53: 1967-2022 (1981). The chemistry, metabolism, and residue analysis of synthetic pyrethroids.

Hutson DH; Progress in Drug Metabolism 3: 215-252 (1979). The metabolic fate of synthetic pyrethroid insecticides in mammals.

Gammon DW; Fundam Appl Toxicol (5) 1: 9-23 (1985). Correlations between in vitro and in vivo mechanisms of pyrethroid insecticide action.

Casida JE et al; Ann Rev Pharmacol Toxicol 23: 413-38 (1983). The mechanisms of selective action of pyrethroid insecticide are discussed.

Papadopoulou-Mourkidou E; Residue Rev 89: 179-208 (1983). A review with many references on analysis of allethrin & other pyrethroid insecticides.

Synonyms and Identifiers:

Synonyms:

Butoflin
**PEER REVIEWED**

Butoss
**PEER REVIEWED**

Butox
**PEER REVIEWED**

Cislin
**PEER REVIEWED**

Crackdown
**PEER REVIEWED**

(S)-alpha-cyano-3-phenoxybenzyl(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethyl- cyclopropanecarboxylate
**PEER REVIEWED**

(S)-alpha-Cyano-3-phenoxybenzyl-(1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethyl- cyclopropane carboxyate
**PEER REVIEWED**

[1R-[1alpha(S*),3alpha]]-cyano(3-phenoxyphenyl)methyl 3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylate
**PEER REVIEWED**

(1R-(1-alpha(S*),3-alpha))-Cyano-(3-phenoxyphenyl)methyl-3-(2,2-dibromovinyl)- 2,2-dimethylcyclopropanecarboxylate)
**PEER REVIEWED**

Decamethrin
**PEER REVIEWED**

Decis
**PEER REVIEWED**

Dekametrin (Hungarian)
**PEER REVIEWED**

Deltamethrine
**PEER REVIEWED**

3-(2,2-Dibromoethenyl)-2,2-dimethylcyclopropanecarboxylic acid cyano(3-phenoxy- phenyl)-methyl ester
**PEER REVIEWED**

Pesticide Code: 097805
**PEER REVIEWED**

Esbecythrin
**PEER REVIEWED**

FMC 45498
**PEER REVIEWED**

JMC 45498
**PEER REVIEWED**

NRDC 161
**PEER REVIEWED**

K-Othrin
**PEER REVIEWED**

K-Othrine
**PEER REVIEWED**

RU 22974
*PEER REVIEWED**

Formulations/Preparations:

USEPA/OPP Pesticide Code 097805; Trade Names: DECIS, FMC 45498, NRDC 161, Butoflin, Butox, Othrin, RU 22974, Othrine dust, striker IEC Insecticide (097805+121501).
[U.S. Environmental Protection Agency/Office of Pesticide Program's Chemical Ingredients Database on Deltamethrin (52918-63-5). Available from the Database Query page at http://www.cdpr.ca.gov/docs/epa/epamenu.htm as of February 5, 2001.]**PEER REVIEWED**

Emulsifiable concentrate; wettable powder; ULV liquid; suspension concentrate; granules; dustable powder, fogging concentrate.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Mixed formulations: (deltamethrin +) heptenophos, sulphur
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.,p. A122/Aug 87]**PEER REVIEWED**

Domestic Bulgarian insecticide "Dekazol" /contains/ 0.02, 0.04, or 0.08% deltamethrin ... .
[WHO; Environmental Health Criteria 97: Deltamethrin p.87 (1990)]**PEER REVIEWED**

Administrative Information:

Hazardous Substances Databank Number: 6604
Last Revision Date: 20011010
Last Review Date: Reviewed by SRP on 5/10/2001
Update History:

Complete Update on 10/10/2001, 54 fields added/edited/deleted.
Field Update on 08/08/2001, 1 field added/edited/deleted.
Field Update on 05/16/2001, 1 field added/edited/deleted.
Complete Update on 09/12/2000, 1 field added/edited/deleted.
Complete Update on 06/12/2000, 1 field added/edited/deleted.
Complete Update on 02/08/2000, 1 field added/edited/deleted.
Complete Update on 02/02/2000, 1 field added/edited/deleted.
Complete Update on 09/21/1999, 1 field added/edited/deleted.
Complete Update on 08/27/1999, 1 field added/edited/deleted.
Complete Update on 06/08/1999, 7 fields added/edited/deleted.
Field Update on 06/03/1998, 1 field added/edited/deleted.
Field Update on 11/01/1997, 1 field added/edited/deleted.
Field Update on 05/09/1997, 1 field added/edited/deleted.
Complete Update on 03/17/1997, 1 field added/edited/deleted.
Complete Update on 02/28/1997, 1 field added/edited/deleted.
Complete Update on 10/20/1996, 1 field added/edited/deleted.
Complete Update on 05/14/1996, 1 field added/edited/deleted.
Complete Update on 02/01/1996, 1 field added/edited/deleted.
Complete Update on 08/21/1995, 1 field added/edited/deleted.
Complete Update on 11/28/1994, 2 fields added/edited/deleted.
Complete Update on 11/21/1994, 1 field added/edited/deleted.
Complete Update on 09/08/1994, 2 fields added/edited/deleted.
Complete Update on 03/01/1994, 63 fields added/edited/deleted.

Record Length: 184986