Use of cholinesterase in Aporrectodea caliginosa (Oligochaeta; Lumbricidae) to detect organophosphate contamination: Comparison of laboratory tests, mesocosms, and field studies

Acute and sublethal enzyme responses were assessed in the earthworm Aporrec todea caliginosa (Savigny) exposed to chlorpyrifos and diazinon in the labo ratory, mesocosms, and field exposures. The aim of this work was to evaluat e whether cholinesterase (ChE) activity has potential as a biomarker of org anophosphate exposure in earthworms. No mortality or population changes wer e found at the recommended field application rates of the pesticides in the three experimental systems. Cholinesterase activity was severely inhibited in earthworms exposed to sublethal doses in laboratory tests. However, no effects of the pesticides on ChE were found in the mesocosm or natural worm populations.