|RODGERS, JR, J|
|Smith Jr, Sammie|
Submitted to: Journal of Society of Environmental Toxicology and Chemistry
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/1997
Publication Date: N/A
Technical Abstract: Laboratory toxicity data contrasting organism responses to insecticides are important for focusing on sensitive species exposed to aqueous concentrations of chlorpyrifos, chlordane, and aldicarb in field studies. These data also allow prediction of expected responses of aquatic species to a range of insecticide concentrations in situ. Aqueous 48 h toxicity experiments were performed to contrast responses of invertebrates and fish to acetylcholinesterase-inhibiting insecticides: chlorpyrifos, aldicarb, and chlordane. As expected, invertebrates tested (*H. azteca*, *C. tentans*, and *D. magna*) were greater than or equal to 200 times more sensitive than the vertebrate *P. promelas* to chlorpyrifos. *H. azteca* was approximately 3.5 times more sensitive to chlorpyrifos (453% mortality/ug/L or 100% mortality/0.22 ug/L) than *D. magna* (128% mortality/ug/L, respectively). Differences in chlordane potency for test species varied only by a factor of approximately 2-3 (0.88% mortality/ug/L for *H. azteca* to 2.54% mortality/ug/L for *C. tentans*). While point estimates of population responses such as LC50s, NOECs, and LOECs are of some utility for predicting effects of pesticides in aquatic systems, exposure-response slopes are also useful for extrapolation of laboratory data to diverse field situations, especially where sediment sorption may regulate exposure or bioavailability.