Using fragmenting enchytraeid species in ecotoxicological tests: regeneration as a new endpoint

Abstract Enchytraeids (potworms) are widely distributed oligochaetes highly useful as bioindicators of soil quality and for ecotoxicological tests to assess non-target effects of contaminants. However, the standard and most widely-used species (Enchytraeus albidus and Enchytraeus crypticus) are not well representative of potworms living in agricultural soils subjected to pesticide use in temperate and tropical regions. Fragmenting species like Enchytraeus bigeminus may be more ecologically relevant, and their rapid reproduction mode (fragmentation) may reduce assay time, offering faster and more economical results. In the present study we provide first results of ecotoxicological tests using the reference substance Boric Acid and the regeneration of E. begeminus fragments as a new end-point. Decreases in regeneration after 7 days exposure were observed with higher concentrations of boric acid and EC50 value was 9.12 mg kg-1. Regeneration was easily visible and rapidly assessed using a Ludox® and white paint solution, making this fragmenting species and endpoint particularly interesting for further standardization efforts.