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ATOXNET PIP-CARBARYL `ttp://ace.orst.edu/cgi-bin/mfs/01/pips/carbaryi.litin burns. Inhalation or ingestion of very large amounts can be toxic to the nervous and respiratory systems resulting in nausea, stomach cramps, diarrhea, and excessive salivation. Other symptoms at high doses include sweating, blurring of vision, incoordination, and convulsions. The only documented fatality from carbaryl was through intentional ingestion. The oral LD50 of carbaryl ranges from 250 mg/kg to 850 mg/kg in rats, and from 100 mg/kg to 650 mg/kg in mice [8,24]. The inhalation LC50 in rats is greater than 200 mg/L [24]. Low doses can cause minor skin and eye irritation in rabbits, a species in which carbaryl's dermal LD50 has been measured at greater than 2000 mg/kg [8]. • Chronic toxicity: Not Available • Reproductive effects: No reproductive or fetal effects were observed during a long-term study of rats fed high doses of carbaryl [8]. • Teratogenic effects: The evidence for teratogenic effects due to chronic exposure is minimal in test animals. Birth defects in rabbit and guinea pig offspring occurred only at dosage levels that were highly toxic to the mother [25]. • Mutagenic effects: Carbaryl has been shown to affect cell division and chromosomes in rats [24]. However, numerous studies indicate that carbaryl poses only a slight mutagenic risk [8,26]. There is a possibility that carbaryl may react in the human stomach to form a more mutagenic compound, but this has not been demonstrated. In sum, the evidence suggests that carbaryl is unlikely to be mutagenic to humans [26,27]. • Carcinogenic effects: Technical-grade carbaryl has not caused tumors in long-term and lifetime studies of mice and rats. Rats were administered high daily doses of the pesticide for 2 years, and mice for 18 months, with no signs of carcinogenicity [28]. While N-nitrosocarbaryl, a possible by-product, has been shown to be carcinogenic in rats at high doses, this product has not been detected. Thus, the evidence indicates that carbaryl is unlikely to be carcinogenic to humans [29]. • Organ toxicity: Ingestion of carbaryl affects the lungs, kidneys, and liver. Inhalation will also affect the lungs [5,30]. Nerve damage can occur after administration of high doses for 50 days in rats and pigs [18]. Several studies indicate that carbaryl can affect the immune system in animals and insects. Male volunteers who consumed low doses of carbaryl for 6 weeks did not show symptoms, but tests indicate slight changes in their body chemistry [8]. A 2-year study with rats revealed no effects at or below a dose of 10 mg/kg/day [25]. • Fate in humans and animals: Most animals, including humans, readily break down carbaryl and rapidly excrete it in the urine and feces. Workers occupationally exposed by inhalation to carbaryl dust excreted 74% of the inhaled dose in the urine in the form of a breakdown product [24]. The metabolism of up to 85% of carbaryl occurs within 24 hours after administration [24]. Ecological Effects: • Effects on birds: Carbaryl is practically nontoxic to wild bird species. The LD50 values are greater than 2000 mg/kg in mallards and pheasants, 2230 mg/kg in quail, and 1000 to 3000 mg/kg in pigeons [10]. • Effects on aquatic organisms: Carbaryl is moderately toxic to aquatic organisms, such as rainbow trout(LC50 of 1.3 mg/L), and bluegill (LC50 of 10 mg/L) [10]. Some accumulation of carbaryl can occur in catfish, crawfish, and snails, as well as in algae and duckweed. Residue levels in fish were 140-fold greater than the concentration of carbaryl in water. In general, due to its rapid metabolism and rapid degradation, carbaryl should not pose a significant bioaccumulation risk in alkaline — waters. However, under conditions below neutrality, it may be significant [10]. • Effects on other organisms: Carbaryl is lethal to many non-target insects, including bees and beneficial insects [10]. 0l'4 5/12:00 1:54 Ph1