Secondary poisoning in the common shrew (Sorex araneus) fed earthworms exposed to an organophosphate pesticide

Abstract

AbstractEarthworms Esinia spp. were kept for a 48‐h period in artificial soil contaminated with a sublethal dose of dimethoate, an organophosphate pesticide. Different groups of common shrews, Sorex araneus, were fed earthworms that had been exposed to contaminated soil either 1, 5, or 10 d previously. Cholinesterase (ChE) activity was measured in worms and in the shrews before and after they were fed contaminated worms. After exposure to dimethoate‐treated soil, ChE activity in worms was inhibited by 90%. Recovery was slow, and ChE activity was still markedly inhibited (35% of the control level) 40 d after exposure. Whole blood ChE activity in shrews was significantly depressed (64% of preexposure levels) when animals were fed worms that had been exposed to dimethoate‐treated soil on the previous day. There was no such significant inhibition in shrews fed worms that had been exposed to contaminated soil either 5 or 10 d previously.