title: Toxicity of sixty-three metals and metalloids to Hyalella azteca at two levels of water hardness.
abstract: The toxicity of all atomically stable metals in the periodic table, excluding Na, Mg, K, and Ca, was measured in one-week exposures using the freshwater amphipod Hyalella azteca in both Lake Ontario, Canada, and soft water (10% Lake Ontario). Metals were added as atomic absorption standards (63 metals), and also as anion salts for 10 metals. Lethal concentrations resulting in 50% mortality (LC50s) were obtained for 48 of the metals tested; the rest were not toxic at 1,000 microg/L. The most toxic metals on a molar basis were Cd, Ag, Pb, Hg, Cr (anion), and Tl, with nominal LC50s ranging from 5 to 58 nmol/L (1 to 58 nmol/L measured). These metals were followed by U, Co, Os, Se (anion), Pt, Lu, Cu, Ce, Zn, Pr, Ni, and Yb with nominal LC50s ranging from 225 to 1,500 nmol/L (88-1,300 nmol/L measured). Most metals were similarly or slightly more toxic in soft water, but Al, Cr, Ge, Pb, and U were >17-fold more toxic in soft water; Pd was less toxic in soft water. Atomic absorption (AA) standards of As and Se in acid had similar toxicity as anions, Sb was more toxic as the AA standard, and Cr and Mn were more toxic as anions. One-week LC50s for H. azteca correlate strongly with three-week LC50s and three-week effect concentrations resulting in 50% reduction in reproduction (EC50s) in Daphnia magna.
authors.affiliation: National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada. uwe.borgmann@ec.gc.ca
authors.forename: Uwe
authors.initials: U
authors.lastname: Borgmann
authors.forename: Yves
authors.initials: Y
authors.lastname: Couillard
authors.forename: Patrick
authors.initials: P
authors.lastname: Doyle
authors.forename: D George
authors.initials: DG
authors.lastname: Dixon
mesh_terms: D033304:Amphipoda / Q000187:drug effects*; D000818:Animals; D007928:Lethal Dose 50; D008670:Metals / Q000633:toxicity*; D009864:Ontario; D014867:Water / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical; D014867:Water