title: The use of bioassays and toxicity identification evaluation (TIE) procedures to assess recovery and effectiveness of remedial activities in a mine drainage-impacted stream system.
abstract: Effluents from Walker Mine and its tailings pile have resulted in toxic concentrations of metals in Dolly and Little Grizzly Creeks. Recent remedial structures have greatly reduced metal loading, however the need to assess recovery of the receiving aquatic ecosystem exists so that future remediation priorities can be established. The objective was to contribute to this assessment using Toxicity Identification Evaluation procedures. Water samples were collected at several sites in Dolly and Little Grizzly Creeks. Untreated samples and samples passed through ion exchange columns, which remove cationic metals, were compared in side-by-side bioassays using Pimephales promelas, Ceriodaphnia dubia, and Selenastrum capricornutum. Samples were analyzed for total and dissolved copper, cadmium, zinc, and iron. Copper was the element responsible for toxicity. Toxicity was detected in the mine discharge and immediately downstream from the tailings where dissolved copper concentrations were 250 microg/L and 415 microg/L, respectively. Toxicity decreased at downstream sites but extended at least 6.4 km downstream. Improvement in bioassay performance by the treated waters verified metal toxicity. The results indicate that the mine effluent and tailings pile currently have the heaviest impact on Dolly and Little Grizzly Creeks and should be given the highest priority in future remedial programs.
authors.affiliation: Department of Anatomy, Physiology, and Cell Biology, School of Veterinarian Medicine, University of California, Davis, California 95616, USA.
authors.forename: L
authors.initials: L
authors.lastname: Deanovic
authors.forename: V M
authors.initials: VM
authors.lastname: Connor
authors.forename: A W
authors.initials: AW
authors.lastname: Knight
authors.forename: K J
authors.initials: KJ
authors.lastname: Maier
mesh_terms: D000818:Animals; D002140:California; D000460:Chlorophyta / Q000187:drug effects; D003530:Cyprinidae; D003621:Daphnia / Q000187:drug effects; D005618:Fresh Water / Q000032:analysis*; D008906:Mining; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical