title: Acute toxicity of sodium selenate to two daphnids and three amphipods.
abstract: This study evaluated the acute toxicity of sodium selenate to two daphnid and three gammarid amphipod species. The daphnids, Ceriodaphnia dubia and Daphnia pulex, were evaluated in 48-hour static tests and the amphipods, Gammarus pseudolimnaeus, Gammarus lacustris, and Hyalella azteca, were evaluated in 96-hour static and flow-through tests. Tests resulted in mean LC50's of 1.92, 9.12, 1.82, 3.05, and 1.95 mg/L selenium for C. dubia, D. pulex, G. pseudolimnaeus, G. lacustris, and H. azteca, respectively. The LC50's for the G. pseudolimnaeus tests are more than 30-fold higher than previously reported LC50's for the same or similar species. The explanation for these differing results appears to be partially, but not entirely, explained by differences in ambient pH between the new studies and previous ones. Depending on how the new data are included in U.S. EPA's selenium freshwater quality criterion data set, the selenate acute water quality criterion (i.e., Criterion Maximum Concentration) increases from 12.8 to as high as 583 microg/L selenium.
authors.affiliation: EcoTox, North Bend, Washington 98045, USA.
authors.forename: K V
authors.initials: KV
authors.lastname: Brix
authors.forename: D G
authors.initials: DG
authors.lastname: Henderson
authors.forename: W J
authors.initials: WJ
authors.lastname: Adams
authors.forename: R J
authors.initials: RJ
authors.lastname: Reash
authors.forename: R G
authors.initials: RG
authors.lastname: Carlton
authors.forename: D O
authors.initials: DO
authors.lastname: McIntyre
mesh_terms: D000818:Animals; D003445:Crustacea / Q000187:drug effects*; D004784:Environmental Monitoring / Q000592:standards*; D005618:Fresh Water; D064586:Selenic Acid; D018036:Selenium Compounds / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D018036:Selenium Compounds; D014874:Water Pollutants, Chemical; D064586:Selenic Acid