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The effect of calcium and magnesium ratios on the toxicity of copper to five aquatic species in freshwater
Author(s) -
Naddy Rami B.,
Stubblefield William A.,
May Jeffrey R.,
Tucker Scott A.,
Hockett J. Russell
Publication year - 2002
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620210217
Subject(s) - daphnia magna , hard water , ceriodaphnia dubia , gammarus , toxicity , copper toxicity , copper , environmental chemistry , calcium , soft water , magnesium , chemistry , alkalinity , gammarus pulex , acute toxicity , amphipoda , biology , crustacean , ecology , organic chemistry
While it is generally accepted that water hardness affects copper toxicity, the major ions that contribute to water hardness (calcium [Ca] and magnesium [Mg]) may affect copper toxicity differently. This is important because the Ca:Mg ratio in standard laboratory‐reconstituted waters often differs from the ratio in natural surface waters. Copper toxicity was assessed for five different aquatic species: rainbow trout (RBT), fathead minnow (FHM), Ceriodaphnia dubia, Daphnia magna , and an amphipod ( Gammarus sp.) under different Ca:Mg ratios (4:0, 3:1, 1:1, 1:3, and 1:4 mass basis) at a common hardness (180 mg/L as CaCO 3 ) and alkalinity (120 mg/L as CaCO 3 ). Copper toxicity increased at lower Ca:Mg ratios for RBT but increased at higher Ca:Mg ratios for D. magna . Fathead minnows (<24 h old) were more sensitive to copper in 1:1 Ca:Mg waters compared to 3:1 Ca:Mg waters. The toxicity of copper did not vary under different Ca:Mg ratios for Gammarus sp., C. dubia , and 28‐d‐old FHM. The effect of Ca:Mg ratios on copper toxicity changed for D. magna in softer water (90 mg/L as CaCO3) compared with hard water studies.