Is Caenorhabditis elegans representative of freshwater nematode species in toxicity testing?

Multi-species toxicity tests were conducted using a broad range of freshwater nematode species to assess interspecific differences in sensitivity to chemical stress and to compare the toxicity to that on the standard test organism Caenorhabditis elegans. The lethal effects of nine different chemical treatments, including metals and polycyclic aromatic hydrocarbons (PAHs) in single and mixture application, were determined for nematodes exposed for 48 h to spiked aqueous solutions. The investigated freshwater nematodes exhibited distinct differences in their sensitivity. Ranking of the susceptibility of 27 species to chemical stress showed that the effects were largely independent of the tested chemical compounds. Overall, the responses of C. elegans were well within the range of those of freshwater nematode species, being slightly less tolerant to metals, but more tolerant to PAHs than the average freshwater species response. Therefore, this study justified the use of C. elegans as representative model for freshwater nematode species in toxicity testing.