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KTOXNET PIP - LAMBDA CYHALOTHRIN Page 2 of 4
<br /> take the form of stable,repetitive firing of the neuron,but high doses may result in depolarization of the nerve
<br /> cell and blockage of conduction(108).These effects may result in observable effects such as: tingling,burning or
<br /> numbness sensations (particularly at the point of skin contact);tremors, incoordination of movement,,paralysis
<br /> or other disrupted motor function; and confusion or loss of consciousness (108). Since most pyrethroids are
<br /> generally absorbed only poorly through the skin(108, 109),the latter two systemic effects are unlikely unless the
<br /> compound has been ingested.Effects are generally reversible due to rapid breakdown of the compound in the
<br /> body (108, 109). Like many compounds of the pyrethroid family, the observed toxicity of lambda cyhalothrin
<br /> may vary according to not only the concentration of the active ingredient,but also according to the solvent
<br /> vehicle (62).
<br /> • Chronic Toxicity: The principal toxic effects noted in chronic studies were decreased body weight gain and
<br /> decreased food consumption. These effects occurred in rats at oral doses of 1.5 mg/kg/day (the highest dose
<br /> tested)in a three-generational study conducted in 1984 (107, 110). In a two-year study in rats, no effects were
<br /> observed at oral doses of 2.5 mg/kg/day and doses of up to 8.5 mg/kg/day produced no observable changes in the
<br /> function or structure of the liver or nervous system (107, 110). In this study, decreased body weight gain and
<br /> decreased food consumption occurred at doses of 12.5 mg/kg/day as did elevation of plasma triglycerides (107,
<br /> 110). In a 26 week feeding study on dogs, doses of 2.5 mg/kg/day disrupted water absorption from the small
<br /> intestine resulting in liquid feces (107, 110), and at doses of 3.5 mg/kg/day and higher, neurological effects were
<br /> noted (109). In two teratology studies,no maternal toxicity was observed at doses of 10 mg/kg/day in both rats
<br /> and rabbits (107, 110 ). It is unlikely that lambda cyhalothrin would cause chronic effects in humans under
<br /> normal conditions.
<br /> • Reproductive Effects: In two studies, lambda cyhalothrin caused reduced body weight gain at doses of 15
<br /> mg/kg/day in pregnant rats (highest dose tested) and at doses of 30 mg/kg/day in pregnant rabbits (also the
<br /> highest dose tested) (107, 110),but these doses produced no observable reproductive effects. There were reduced
<br /> numbers of viable offspring at doses of 50 mg/kg/day in the second and third generations in the three-
<br /> generational rat study noted above (107, 110). It is unlikely that lambda cyhalothrin would cause reproductive
<br /> effects in humans under normal conditions.
<br /> • Teratogenic Effects: No teratogenic or fetotoxic effects were observed in teratology studies of lambda
<br /> cyhalothrin in rats and rabbits at the highest doses tested in both species (15 mg/kg/day and 30 mg/kg/day,
<br /> respectively;(107, 110). Based on these data, it is unlikely that lambda cyhalothrin causes teratogenic effects.
<br /> • Mutagenic Effects: Lambda cyhalothrin produced negative results in all Ames mutagenicity assays using five
<br /> different test strains,both with and without metabolic activation (12, 109). Results of other in-vitro cytogenetic
<br /> assays and chromosomal structural aberration tests indicated no mutagenic or genotoxic effects were caused by
<br /> lambda cyhalothrin(107, 109). The available evidence suggests that lambda cyhalothrin is non-mutagenic and
<br /> non-genotoxic.
<br /> • Carcinogenic Effects: No carcinogenic effects have been noted in studies of lambda cyhalothrin on various test
<br /> animals (rats,rabbits, dogs) (107). The evidence regarding the carcinogenicity of lambda cyhalothrin is
<br /> inconclusive,but suggests that it is probably not carcinogenic.
<br /> • Organ Toxicity: No specific target organs or organ systems have been identified in the available studies of
<br /> chronic toxicity. The nervous system may be affected after acute exposure.
<br /> • Fate in Humans & Animals: In rat studies, lambda cyhalothrin is rapidly metabolized and excreted via the urine
<br /> and feces (12). Hydrolytic cleavage of the ester bond occurs, forming more polar,water-soluble compounds
<br /> which are less toxic and more easily eliminated (12, 110).
<br /> ECOLOGICAL EFFECTS
<br /> • Effects on Birds: Lambda cyhalothrin's toxicity to birds ranges from slightly toxic to practically non-toxic. In
<br /> the mallard duck,the reported oral LD50 is greater than 3,950 mg/kg (12, 107), and the reported dietary LC50 is
<br /> 3,948 ppm (107). In bobwhite quail the reported dietary LC50 is greater than 500 ppm(12, 107). There is
<br /> evidence that it does not accumulate in the eggs or tissues of birds(12).
<br /> • Effects on Aquatic Organisms: Lambda cyhalothrin is very highly toxic to many fish and aquatic invertebrate
<br /> species. Reported LC50s in these species are as follows: bluegill sunfish, 0.21 ug/L (12, 107); rainbow trout, 0.24
<br /> ug/L (12, 107); Daphnia magna, 0.36 ug/L (107); mysid shrimp, 4.9 ng/L (107); sheepshead minnow, 0.807 ng/L
<br /> (107). A median effect concentration, EC50 (i.e. the concentration at which the effect occurs in 50%of the test
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