Abstract
We performed acute toxicity tests using 2-chloroacetamide（a fungicide）on Eisenia fetida to compare susceptibility among various-sized earthworms. A controlled method of rearing Eisenia fetida was developed to provide individuals of the desired sizes. Eisenia fetida was cultured in an artificial soil using a mixture of dried rolled barley and spinach （4:1）powder as food in a controlled room（20［or 22］±1°C; 18［or 16］-h light: 6［or8］-h dark）．Cocoons（four hundreds, usually）collected from the artificial soil were introduced into rearing water（dechlorinated tap water），and hatched juveniles were cultured in the artificial soil to the desired weight. Our findings indicate that small individuals（30～100 mg wet wt.）may be used for the acute toxicity test instead of adult earthworm（OECD test guideline <: 300 mg）to diminish the amount of contaminated soils and space （continuous light）required for the toxicity test. Other test conditions such as continuous light during the test（TG-204），testing chemicals in water instead of the filter paper contact rest（TG-204），and suitability of 2-chloroacetoamide as a reference substance were also investigated to improve the efficiency of the earthworm toxicity test.
