SU0000027 SSC RPT - Laserfiche WebLink

Home Browse Search

EXFOXNET PIP-E5FE•NVALERATE htip:/iace.orst.cdu/cgi-bin/mis/ol/pips/csfenval.htm i in the two products are the relative proportions of the four separate constituents (isomers). Esfenvalerate has become the preferred compound because it requires lower applications rates than fenvalerate, is less chronically toxic, and is a more powerful insecticide. The compound contains a much higher percentage of the one insecticidally active isomer(84% for esfenvalerate and 22% for fenvalerate). Toxicological Effects: 4 • Acute toxicity: Esfenvalerate is a moderately toxic compound via the oral route. The reported oral LD50 of esfenvalerate is 458 mg/kg in rats. It is slightly toxic via the dermal route, with a reported dermal LD50 of 2500 mg/kg in rabbits. It is practically non-toxic via inhalation, with a reported inhalation LC50 of greater than 2.93 mg/L in rats [2,12]. Because esfenvalerate is a relatively new compound it has little usage history. The bulk of evidence related to acute poisonings in humans due to esfenvalerate comes from incidents in India. Nearly 600 individual cases of poisoning were reported between 1982 and 1988. These cases were due to improper handling of the pesticide. Acute toxic effects were observed in workers and among the general public. Symptoms of acute poisoning included dizziness, burning and itching (which was worsened by sweating and washing). r Severe cases of direct contact caused blurred vision, tightness in the chest, and convulsions (2). The changes appear to be reversible. In rats, high acute exposure to esfenvalerate produced muscle incoordination, tremors, convulsions, nerve damage, and weight loss. The compound may produce nausea, vomiting, headache, temporary nervous system effects such as weakness, tremors, and incoordination at acute exposure levels in humans. Esfenvalerate is a strong eye irritant, producing tearing or blurring of vision. i • Chronic toxicity: Rats fed fenvalerate at concentrations of approximately 12.5 mg/kg/day for two f years had no compound-related changes in the blood or urine [12]. In other studies significant ► reduction in body weight was the main adverse effect seen in both rats and mice of both sexes. • Reproductive effects: In a three-generation rat study, low doses (up to 12.5 mg/kg/day) of fenvalerate produced no toxicity in the fetus. Some maternal toxicity was noted in the second generation at the higher dose. When pregnant mice and rabbits were fed low dietary levels of i fenvalerate (2.5 mg/kg/day) on days_ 6 to 15 of gestation, there was maternal toxicity in both species. It seems that during pregnancy, the females are more sensitive to fenvalerate than they would -otherwise be, even though the toxicity is not reflected in any effect on the fetus [5]. There are no specific data available for esfenvalerate, but it is not expected to cause reproductive effects at low i doses. i Teratogenic effects: Esfenvalerate did not produce any birth defects in offspring at low dietary doses [2]. It appears the the pesticide would not pose a teratogenic threat to humans at expected exposure levels. • Mutagenic effects: Esfenvalerate shows no mutagenic effects. Numerous tests in hamsters, mice and rats show no signs of mutagenic activity associated with this compound [2]. It is likely that it poses no mutagenic risk to humans. • Carcinogenic effects: A rat study of fenvalerate conducted over a wide range of doses of up to 75 mg/kg, for two years, resulted in no evidence of cancer. Mice fed diets containing small amounts of fenvalerate for two years showed no adverse effects [2]. It appears that fenvalerate does not cause cancer. • Organ toxicity: Studies to date have not shown any dose-related effects on internal organs of test h animals or in human populations [2]. • Fate in humans and animals: Cows treated with 0.1 or 0.5 g fenvalerate on their skin had 0.03 to 0.06% of the applied chemical in the milk. When the cows received fenvalerate orally at very low levels, about 0.50% of the dose appeared in the milk. Fenvalerate does not appear to be metabolized by bovine rumen, but it is degraded further down the digestive tract [32]. This happens rapidly with )f 1/26/00 8:59 Adel