Evaluation of seven sediment toxicity tests and their relationships to stream parameters

A survey of sediment microbial activity and toxicity to Daphnia magna, Ceriodaphnia dubia, and Selenastrum capricornutum was conducted on two streams receiving numerous effluents in Ohio—the Little Scioto River and Dick's Creek. Microbial activity assays included alkaline phosphatase, dehydrogenase, β-galactosidase, β-glucosidase. Activity was compared to overlying water chemistry and revealed several statistically significant correlations. No macrofaunal assay toxicity was observed in Dick's Creek. Sediment toxicity was found at two stations in the Little Scioto River, and varied in degree and organism sensitivity with time of sampling. These results support earlier studies suggesting the need for multiple trophic-level assays in aquatic ecosystem evaluations of toxicant impacts.