A toxicity assessment of total dissolved solid ions in mine effluent using two common bioassays: the 22-hour MicroTox assay and a S. carpricornutum growth assay

Abstract

This research evaluated two microassays and a synthetic TDS standard to measure the effects of elevated TDS from mine effluent on biota of freshwater systems. Field samples from Red Dog and Fort Knox mines were tested on Selenastrum capricornutum and the MicroTox assay, and compared to the synthetic standard. Results indicate that the synthetic TDS standard is a poor representation of produced waters with similar total TDS concentrations. Additionally, no correlation was found between the toxicological responses of the two assays. Principle component analysis found the MicroTox assay to be most sensitive to cadmium and chloride. At concentrations present in the field samples, there does not appear to be a relationship between toxicity and TDS as measured on these assays.