Harmon S M, Specht W L, Chandler G T
University of South Carolina, Norman J. Arnold School of Public Health, Department of Environmental Health Sciences, Columbia, South Carolina 29208, USA.
Arch Environ Contam Toxicol. 2003 Jul;45(1):79-85. doi: 10.1007/s00244-002-0116-8.
U.S. regulatory agencies commonly require effluent toxicity testing with Ceriodaphnia dubia--a practice that has led to the criticism that this species and test protocol often does not reflect local taxa or site-specific conditions. Using an indigenous test species may produce a more realistic model of local effects and may minimize test endpoint variance due to regional differences in water quality. This study addressed the substitution of C. dubia with Daphnia ambigua for toxicity testing in the southeastern United States. This investigation determined that D. ambigua could be laboratory cultured with only minimal changes to established regulatory protocol and that the life-cycle characteristics of this species were conducive to traditional acute and chronic aquatic toxicity test methods used with other daphnids. Acute toxicity tests showed that D. ambigua was less sensitive to some toxicants (sodium chloride, copper sulfate, and sodium lauryl sulfate) but more sensitive to others (chlorpyrifos). Chronic tests with copper sulfate and sodium chloride resulted in lower EC50S for D. ambigua reproduction with both compounds. When exposed to low-alkalinity, low-pH stream waters typical of many southeastern United States watersheds, C. dubia demonstrated a significant reproductive depression in two of three streams tested, whereas D. ambigua experienced no chronic effect. These results suggest that D. ambigua may serve as a suitable surrogate for C. dubia as an toxicity indicator species in these types of receiving streams.
美国监管机构通常要求使用大型蚤进行废水毒性测试——这种做法引发了批评，即该物种和测试方案往往不能反映当地的分类群或特定地点的条件。使用本地测试物种可能会产生更符合实际的当地影响模型，并可能因水质的区域差异而使测试终点的差异最小化。本研究探讨了在美国东南部用模糊水蚤替代大型蚤进行毒性测试的问题。该调查确定，模糊水蚤可以在实验室中培养，只需对既定的监管方案进行最小程度的修改，并且该物种的生命周期特征有利于与其他水蚤一起使用的传统急性和慢性水生毒性测试方法。急性毒性测试表明，模糊水蚤对某些毒物（氯化钠、硫酸铜和十二烷基硫酸钠）不太敏感，但对其他毒物（毒死蜱）更敏感。用硫酸铜和氯化钠进行的慢性测试导致模糊水蚤繁殖的半数有效浓度（EC50）较低。当暴露于美国东南部许多流域典型的低碱度、低pH值溪流水中时，在测试的三条溪流中的两条中，大型蚤表现出显著的繁殖抑制，而模糊水蚤没有受到慢性影响。这些结果表明，在这些类型的接纳溪流中，模糊水蚤可能作为大型蚤的合适替代物，作为毒性指示物种。
