A metabolomics based test of independent action and concentration addition using the earthworm Lumbricus rubellus

A major challenge in ecotoxicology is to understand the effects of multiple toxicants on organisms. Here we assess the effects on survival, weight change, cocoon production and metabolism caused by exposure to two similarly acting (imidacloprid/thiacloprid) and two dissimilarly acting (chlorpyrifos/Nickel) chemicals on the earthworm Lumbricus rubellus. We assessed the standard models of concentration addition (CA) and independent action (IA), in conjunction with a metabolomics based approach to elucidate mechanisms of effect. For imidacloprid and thiacloprid the reproductive effects indicated probable additivity.