Assessment of the Effect of Varying Soil Organic Matter Content on the Bioavailability of Malathion to the Common Nightcrawler, Lumbricus terrestris L

This study investigated the effect of soil organic matter content on the bioavailability of malathion to the common nightcrawler, Lumbricus terrestris. Earthworms were exposed for 72 h to malathion on two soil types, 8% organic matter and 55% organic matter. Two different measures of bioavailability, malathion body burdens and tissue cholinesterase activities, were then measured in the malathion exposed animals. There were no significant differences in body burden or cholinesterase levels in L. terrestris exposed to malathion on soils with differing organic matter content. This suggests that absorption into organic matter is not a limiting factor of malathion bioavailability to earthworm species.