Earthworm Acute Toxicity Tests

This Test Guideline includes two methods: a paper contact toxicity test and an artificial soil test. The recommended specie is Eisenia foetida (Michaelsen).

The initial screening test (filter paper contact test) involves exposing earthworms to test substances on moist filter paper in order to identify potentially toxic chemicals to earthworms in soil. Five or more treatment levels in a geometric series and, at least, ten replicates (one worm per vial) for each treatment should be used. Tests are done in the dark and for a period of 48 hours. The artificial soil test gives toxicity data more representative of natural exposure of earthworms to chemicals. It involves keeping earthworms in samples of a precisely defined artificial soil. Five concentrations, in a geometric series, of the test substance have been applied. One concentration resulting in no mortality and one resulting in total mortality should be used. Four replicates for each treatment are recommended. Mortality is assessed 7 and 14 days after application.