Toxicity assessment of reference and natural freshwater sediments with the luminotox assay

Abstract

We (the authors) examined the possibility of adapting the LuminoTox, a recently-commercialised bioanalytical testing procedure initially developed for aqueous samples, to assess the toxic potential of sediments. A significant correlation was shown to exist between LuminoTox-Solid Phase Assay (Lum-SPA) and Microtox Solid Phase Assay (Mic-SPA) indicating that both tests display a similar toxicity response pattern for CRM sediments having differing contaminant profiles. The sediment elutriate Lum-ELU assay displayed toxicity responses (i.e., measurable IC20s) for eight of the 14 CRM sediments, suggesting it is capable of determining the presence of sediment contaminants that are readily soluble in an aqueous elutriate. Lum-SPA and Mic-SPA bioassays were further conducted on 12 natural freshwater sediments and their toxicity responses were again significantly correlated. Finally, Lum-SPA testing undertaken with increasing mixtures of kaolin clay confirmed that its toxicity responses, in a manner similar to those reported for the Mic-SPA assay, are also subject to the influence of fines. While further studies will be required to more fully understand the relationship between Lum-SPA assay responses and the physicochemical makeup of sediments (e.g., grain size, combined presence of natural and anthropogenic contaminants), these preliminary results suggest that LuminoTox testing could be a useful screen to assess the toxic potential of solid media.