The effect of calcium and magnesium ratios on the toxicity of copper to five aquatic species in freshwater

摘要

While it is generally accepted that water hardness affects copper toxicity, the major ion 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 1:4mas basis) at a common hardness (180 mg/L as CaCO_3) and alkalinity (120 mg/L as CaCO_3).