US Geological Survey, Columbia Environmental Research Center, Columbia, Missouri.
Environ Toxicol Chem. 2011 Sep;30(9):2115-25. doi: 10.1002/etc.596. Epub 2011 Jul 20.
Acute and chronic toxicity of copper (Cu) to a unionid mussel (Villosa iris) and a cladoceran (Ceriodaphnia dubia) were determined in water exposures at four concentrations of dissolved organic carbon (DOC; nominally 0.5, 2.5, 5, and 10 mg/L as carbon [C]). Test waters with DOC concentrations of 2.5 to 10 mg C/L were prepared by mixing a concentrate of natural organic matter (Suwannee River, GA, USA) in diluted well water (hardness 100 mg/L as CaCO(3) , pH 8.3, DOC 0.5 mg C/L). Acute median effect concentrations (EC50s) for dissolved Cu increased approximately fivefold (15-72 µg Cu/L) for mussel survival in 4-d exposures and increased about 11-fold (25-267 µg Cu/L) for cladoceran survival in 2-d exposures across DOC concentrations from 0.5 to 10 mg C/L. Similarly, chronic 20% effect concentrations (EC20s) for the mussel in 28-d exposures increased about fivefold (13-61 µg Cu/L for survival; 8.8-38 µg Cu/L for biomass), and the EC20s for the cladoceran in 7-d exposures increased approximately 17-fold (13-215 µg Cu/L) for survival or approximately fourfold (12-42 µg Cu/L) for reproduction across DOC concentrations from 0.5 to 10 mg C/L. The acute and chronic values for the mussel were less than or approximately equal to the values for the cladoceran. Predictions from the biotic ligand model (BLM) used to derive the U.S. Environmental Protection Agency's ambient water quality criteria (AWQC) for Cu explained more than 90% of the variation in the acute and chronic endpoints for the two species, with the exception of the EC20 for cladoceran reproduction (only 46% of variation explained). The BLM-normalized acute EC50s and chronic EC20s for the mussel and BLM-normalized chronic EC20s for the cladoceran in waters with DOC concentrations of 2.5 to 10 mg C/L were equal to or less than the final acute value and final chronic value in the BLM-based AWQC for Cu, respectively, indicating that the Cu AWQC might not adequately protect the mussel from acute and chronic exposure, and the cladoceran from chronic exposure.
铜 (Cu) 对贻贝 (Villosa iris) 和枝角类 (Ceriodaphnia dubia) 的急性和慢性毒性在四个溶解有机碳 (DOC) 浓度的水暴露中进行了测定 (名义上为 0.5、2.5、5 和 10 毫克/升作为碳 [C])。具有 2.5 至 10 mg/L 碳浓度的试验用水通过混合天然有机物 (Suwannee River，GA，USA) 的浓缩物在稀释的井水 (硬度为 100 mg/L 碳酸钙，pH 值为 8.3，DOC 为 0.5 mg C/L) 中制备。在 4 天的暴露中，贻贝存活的溶解铜的急性中位效应浓度 (EC50) 增加了约五倍 (15-72 µg Cu/L)，在 2 天的暴露中，枝角类存活的 EC50 增加了约 11 倍 (25-267 µg Cu/L) ，在 0.5 至 10 mg/L 的 DOC 浓度范围内。同样，贻贝在 28 天暴露中的慢性 20%效应浓度 (EC20) 增加了约五倍 (存活时为 13-61 µg Cu/L; 生物量时为 8.8-38 µg Cu/L)，而枝角类在 7 天暴露中的 EC20 增加了约 17 倍 (存活时为 13-215 µg Cu/L) 或约 4 倍 (繁殖时为 12-42 µg Cu/L) ，在 0.5 至 10 mg/L 的 DOC 浓度范围内。贻贝的急性和慢性值小于或等于枝角类动物的急性和慢性值。用于推导美国环境保护署 (EPA) 铜环境水质标准 (AWQC) 的生物配体模型 (BLM) 的预测解释了两种物种的急性和慢性终点的 90%以上的变化，除了枝角类动物繁殖的 EC20 之外 (仅解释了 46%的变化)。在 2.5 至 10 mg/L DOC 浓度的水中，贻贝的 BLM 归一化急性 EC50 和慢性 EC20 以及枝角类动物的 BLM 归一化慢性 EC20 分别等于或小于 BLM 为 Cu 基于的 AWQC 的最终急性值和最终慢性值，表明 Cu AWQC 可能无法充分保护贻贝免受急性和慢性暴露，以及枝角类动物免受慢性暴露。
