Hazards of Chemicals to Earthworms

Abstract

While great strides have been made in recent years regarding water quality criteria and hazard assessment of chemicals in the aquatic environment, the same is not true for the terrestrial ecosystem. This results in part from the magnitude of the problem and, perhaps, to some degree, from an attitude held by some that animals dwelling in and on the land can better cope with environmental stress than can their aquatic counterparts. Indeed, this sometimes may be the case, but results of our studies with the earthworm Eisenia foetida suggest otherwise. This organism is extremely susceptible to the toxic action of many common pesticides and other chemicals, and there is good evidence that this species is among the more hardy of all the earthworms. Although many facets of the terrestrial ecosystem must be addressed with regard to chemical hazards, practicality dictates that emphasis be directed toward specific organisms representing a given segment of the terrestrial population. This article discusses the vital role of earthworms in the environment and why they are particularly useful as test organisms, and summarizes chemical toxicity data obtained in laboratory and field investigations.

The toxicity of five insecticides to earthworms of the Pheretima group, using an artificial soil test

“…Cyfluthrin is low and chlorpyrifos moderate in direct toxicity to earthworm populations 1. 4, 7, 8, 15 Carbaryl is, however, highly toxic to earthworm populations 2. 7, 8, 10, 15…”

“…Earthworms (Oligochaeta) are important in maintaining soil fertility1–4 and play an important role during the nutrient cycle 5. Earthworms are important for soil formation and soil structure 1.…”

The relative toxicities of insecticides to earthworms of the Pheretima group (Oligochaeta)

“…These methods have varied too much to allow proper reviews on the subject 15. 16 A standardised method, the ‘artificial soil test’, was developed for the EEC (Economic European Community) 9…”

Ecological assessment plan for Waste Area Grouping 5

“…Soil toxicity tests using earthworms and cabbage seedlings in accordance with demonstrated procedures (Green et al 1988;Roberts and Dorough 1985;Guelta 1987, 1988) will be conducted in ESD. For planning purposes, we have assumed that three sites will be identified for testing.…”