Environmental metabolomics: new insights into earthworm ecotoxicity and contaminant bioavailability in soil.

Environmental metabolomics is a growing and emerging sub-discipline of metabolomics. Studies with earthworms have progressed from the initial stages of simple contact exposure tests to detailed studies of earthworm responses in soil. Over the past decade, a variety of endogenous metabolites have been identified as potential biomarkers of contaminant exposure. Furthermore, metabolomic methods have delineated responses from sub-lethal exposure of earthworms to polycyclic aromatic hydrocarbons and metals in soil suggesting that environmental metabolomics may be used as a direct measure of contaminant bioavailability in soil. Environmental metabolomics has the potential to fill knowledge gaps related to earthworm toxicity and contaminant bioavailability. However, challenges with metabolite quantification and limited systems-level models of metabolic data require improvement before detailed models of "normal" responses can be developed and used routinely in assessment of contaminated sites. Nonetheless, environmental metabolomics is poised to improve our fundamental understanding of earthworm responses and toxicity to contaminants in soil.