Soucek David John
Illinois Natural History Survey, Champaign, Illinois 61820, USA.
Environ Toxicol Chem. 2007 Apr;26(4):773-9. doi: 10.1897/06-229r.1.
Based on previous observations that hardness (and potentially chloride) influences sodium sulfate toxicity, the objective of the current study was to quantify the influence of both chloride and water hardness on acute toxicity to Hyalella azteca and Ceriodaphnia dubia. In addition, observed toxicity data from the present study were compared to toxicity predictions by the salinity/ toxicity relationship (STR) model. Hardness had a strong influence on sulfate toxicity that was similar for both crustaceans, and nearly identical median lethal concentration (LC50)/hardness slopes were observed for the two species over the tested range. Chloride had a strong but variable influence on sulfate acute toxicity, depending on the species tested and the concentration range. At lower chloride concentrations, LC50s for H. azteca strongly were correlated positively with chloride concentration, although chloride did not affect the toxicity of sodium sulfate to C. dubia. The opposite trend was observed over the higher range of chloride concentrations where there was a negative correlation between chloride concentration and sulfate LC50 for both species. The widely ranging values for both species and a high correlation between LC50s in terms of sulfate and conductivity suggested that, whether based on sulfate, conductivity, or total dissolved solids (TDS), attempts at water quality standard development should incorporate the fact that water quality parameters such as hardness and chloride strongly influence the toxicity of high TDS solutions. The STR model predicted toxicity to C. dubia relatively well when chloride was variable and hardness fixed at approximately 100 mg/L; however, the model did not account for the protective effect of hardness on major ion/TDS toxicity.
基于之前关于硬度（以及潜在的氯化物）会影响硫酸钠毒性的观察结果，本研究的目的是量化氯化物和水硬度对阿氏摇蚊（Hyalella azteca）和角突网纹溞（Ceriodaphnia dubia）急性毒性的影响。此外，将本研究中观察到的毒性数据与盐度/毒性关系（STR）模型的毒性预测结果进行了比较。硬度对两种甲壳类动物的硫酸盐毒性都有很强的影响，且在测试范围内，两种物种的半数致死浓度（LC50）/硬度斜率几乎相同。氯化物对硫酸盐急性毒性有很强但可变的影响，这取决于所测试的物种和浓度范围。在较低的氯化物浓度下，阿氏摇蚊的LC50与氯化物浓度呈强正相关，尽管氯化物对硫酸钠对角突网纹溞的毒性没有影响。在较高的氯化物浓度范围内观察到相反的趋势，即两种物种的氯化物浓度与硫酸盐LC50之间呈负相关。两种物种的数值范围广泛，且硫酸盐LC50与电导率之间具有高度相关性，这表明，无论是基于硫酸盐、电导率还是总溶解固体（TDS），在制定水质标准时都应考虑到硬度和氯化物等水质参数会强烈影响高TDS溶液的毒性这一事实。当氯化物可变且硬度固定在约100mg/L时，STR模型对角突网纹溞的毒性预测相对较好；然而，该模型没有考虑硬度对主要离子/TDS毒性的保护作用。
