Haloacetic acids (HAAs) are undesirable disinfection by-products (DBPs), released into aquatic ecosystems from various anthropogenic and natural sources. The aim of this study was to examine the ecological risk of exposure to three HAAs commonly detected in water, such as monobromoacetic acid (MBA), monochloroacetic acid (MCA), and trichloroacetic acid (TCA), in in vivo acute and chronic toxicity tests using Daphnia magna as a model. Acute tests showed that MBA was the most toxic of these compounds followed by MCA and TCA as evidenced by immobilization. Aquatic organisms in natural conditions might be exposed simultaneously to numerous compounds; thus, binary mixtures of selected HAAs and a ternary mixture of these were tested. Concentration addition (CA) and independent action (IA) models were used for a predictive assessment of mixture toxicity. Data demonstrated that CA appeared to be the most reliable indicator for HAAs binary and ternary mixtures suggestive of an additive behavior. Median effective concentration (EC50) values from the mixed exposure tests were significantly lower than results obtained from single tests for all three HAAs where an increase of toxicity greater than 50%. Multigenerational chronic tests were also performed exposing daphnids to the ternary mixture of HAAs. A markedly decreased sexual maturity and number of offspring and broods per daphnid especially in the second generation were noted.

中文翻译：

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使用大型蚤（Daphnia magna）对卤代乙酸的急性和慢性毒性评估。

卤乙酸（HAA）是不良的消毒副产物（DBP），从各种人为和天然来源释放到水生生态系统中。这项研究的目的是在体内急性和慢性毒性试验中检查暴露于水中常见的三种HAA（例如一溴乙酸（MBA），一氯乙酸（MCA）和三氯乙酸（TCA））的生态风险。以水蚤（Daphnia magna）为例。急性测试表明，在固定化方面，MBA是这些化合物中毒性最高的，其次是MCA和TCA。自然条件下的水生生物可能同时暴露于多种化合物中。因此，测试了所选HAA的二元混合物和它们的三元混合物。浓度增加（CA）和独立作用（IA）模型用于混合物毒性的预测评估。数据表明，CA似乎是HAA二元和三元混合物最可靠的指标，表明存在加性行为。混合暴露测试的中值有效浓度（EC50）值明显低于毒性增加幅度超过50％的所有三个HAA的单项测试结果。还进行了多代慢性试验，将蚤类动物暴露于HAA的三元混合物中。特别是在第二代中，注意到性成熟度显着降低，每只蚤的后代和亲代数明显减少。混合暴露测试的中值有效浓度（EC50）值明显低于毒性增加幅度超过50％的所有三个HAA的单项测试结果。还进行了多代慢性试验，将蚤类动物暴露于HAA的三元混合物中。特别是在第二代中，注意到性成熟度显着降低，每只蚤的后代和亲代数明显减少。混合暴露测试的中值有效浓度（EC50）值明显低于毒性增加幅度超过50％的所有三个HAA的单项测试结果。还进行了多代慢性试验，将蚤类动物暴露于HAA的三元混合物中。特别是在第二代中，注意到性成熟度显着降低，每只蚤的后代和亲代数明显减少。