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 determine which were the most sensitive biomarkers of exposure and effect for short-term sublethal exposures. There was a significant drop in acetylcholinesterase activity at the two highest concentrations, but no effect on glutathione-S-transferase activity. Behavioral and life history biomarkers were sensitive only to the highest concentration of chlorpyrifos. The association of life history changes (female weight and male emergence times) with a significant inhibition of acetylcholinesterase activity suggests that this can be used as a biomarker of exposure and effect.

Short-term exposure to sub-lethal doses of lindane affects developmental parameters in Chironomus riparius Meigen, but has no effect on larval glutathione-S-transferase activity

Chironomus riparius Meigen were exposed to 0, 0.01, 0.1, 0.5, 0.75 and 1.0 ppm lindane for 48 h as fourth instar larvae. Exposure had no effect on glutathione-S-transferase (GST) activity in larvae snap-frozen immediately following exposure. In contrast, exposure had longer-term consequences affecting developmental parameters. Concentrations above 0.5 ppm lindane affected larval behaviour, reduced adult body size and fecundity and delayed emergence times. The lack of significant change in GST activity when life history characters were affected by high concentrations of lindane, suggests that in C. riparius, GST is not a sensitive biomarker of pesticide exposure or effect.