1.1 ,This guide covers procedures for obtaining laboratory data to evaluate the adverse effects of contaminants (for example, chemicals or biomolecules) associated with soil to earthworms (Family Lumbricidae) and potworms (Family Enchytraeidae) from soil toxicity or bioaccumulation tests. The methods are designed to assess lethal or sublethal toxic effects on earthworms or bioaccumulation of contaminants in short-term tests (7 to 28 days) or on potworms in short to long-term tests (14 to 42 days) in terrestrial systems. Soils to be tested may be (1) reference soils or potentially toxic site soils, (2) artificial, reference, or site soils spiked with compounds, (3) site soils diluted with reference soils, or (4) site or reference soils diluted with artificial soil. Test procedures are described for the species Eisenia fetida (see Annex A1) and for the species Enchytraeus albidus (see Annex A4). Methods described in this guide may also be useful for conducting soil toxicity tests with other lumbricid and enchytraeid terrestrial species, although modifications may be necessary.