Effect of short-term exposure to chlorpyrifos on developmental parameters and biochemical biomarkers in Chironomus riparius Meigen

Chironomus riparius Meigen were exposed to sediment spiked with 0, 0.01, 0. 05, and 0.10 mg chlorpyrifos/kg dry sediment for 48 h as late third-instar larvae. Acetylcholinesterase activity, glutathione-S-transferase activity, burrowing behavior, emergence time, and adult dry weight were measured to d etermine which were the most sensitive biomarkers of exposure and effect fo r short-term sublethal exposures. There was a significant drop in acetylcho linesterase activity at the two highest concentrations, but no effect on gl utathione-S-transferase activity. Behavioral and life history biomarkers we re sensitive only to the highest concentration of chlorpyrifos. The associa tion of life history changes (female weight and male emergence times) with a significant inhibition of acetylcholinesterase activity suggests that thi s can be used as a biomarker of exposure and effect. (C) 2001 Academic Pres s.