Assessment of the toxic potential of sediment organic pollution by Selenastrum capricornutum

The potential risk associated with the sediment-borne organic micropollutan ts from the River Po (Italy) was evaluated using algal toxicity bioassays o n Selenastrum capricornutum. Bed sediment samples were taken downstream fro m the confluence of the main tributaries of the river during two sampling s easons. A solvent extraction procedure of sediment fine fraction was used f or both analytical and toxicological characterization. A good agreement was found between toxicity data and levels of most analyzed contaminants, sugg esting a combined action of the organic mixtures affecting the algal respon ses. The ecotoxicological approach proved to be sensitive for the detection of pollution sites along the river course.