Burmaster D E, von Stackelberg K E
Alceon Corporation, Cambridge, Massachusetts 02238.
Qual Assur. 1992 Jun;1(3):192-206.
Based on material published by the U.S. Environmental Protection Agency (U.S. EPA) in the Federal Register for 19 November 1991, many state environmental agencies have proposed and/or adopted revisions to their State Water Quality Standards (WQS) for organic and inorganic chemicals in fresh and marine waters (see, for example, State of Connecticut, Department of Environmental Protection, Bureau of Water Management, (1992), memorandum to Interested Parties concerning the Water Quality Standards Hearing Report). Generally, many states simply republish the U.S. EPA's proposed Water Quality Criteria (WQC) as the State's proposed WQS. Many of the state WQS and federal WQC values--especially those for organic compounds regulated as human or animal carcinogens--are much more stringent than the values now in effect because the U.S. EPA's new methodology (i) for estimating exposure point concentrations, exposure doses, carcinogenic potency, and incremental lifetime cancer risk and (ii) for setting the target acceptable risk combine a series of conservative assumptions into an equally conservative set of results. In the Federal Register proposal, the U.S. EPA failed to honor its standard risk assessment methodology in that (i) it failed to perform a quantitative or even qualitative uncertainty analysis and (ii) it failed to analyze the overall degree of conservatism in the results. The U.S. EPA suggested that the analysis is suitably conservative for the average exposed adult, but it failed to consider various phenomena that make the proposed WQC far more conservative than acknowledged or intended. To focus on a central problem of manageable size, this article dissects the method by which the U.S. EPA calculates proposed WQC for organic chemicals regulated as human or animal carcinogens. Because the results for most such chemicals are driven by the pathway for the human ingestion of fish which have bioconcentrated the chemicals from the water column (as opposed to the pathway for direct ingestion of water by humans), this article focuses exclusively on the fish-to-human pathway. These considerations form the basis of general quality assurance criteria and standards.
根据美国环境保护局（U.S. EPA）1991年11月19日在《联邦公报》上发布的材料，许多州环境机构已提议和/或通过了对其淡水和海水中有机和无机化学品的州水质标准（WQS）的修订（例如，见康涅狄格州环境保护部水管理局，（1992年），给有关水质标准听证报告的相关方的备忘录）。一般来说，许多州只是将美国环境保护局提议的水质标准（WQC）重新发布为该州提议的WQS。许多州WQS和联邦WQC值——尤其是那些针对被规定为人类或动物致癌物的有机化合物的值——比目前生效的值更为严格，因为美国环境保护局的新方法（i）用于估计接触点浓度、接触剂量、致癌效力和终生癌症风险增量，以及（ii）用于设定目标可接受风险，将一系列保守假设合并为一组同样保守的结果。在美国环境保护局的《联邦公报》提案中，它未能遵循其标准风险评估方法，因为（i）它没有进行定量甚至定性的不确定性分析，（ii）它没有分析结果中的总体保守程度。美国环境保护局表示，该分析对于平均接触的成年人来说具有适当的保守性，但它没有考虑到各种使提议的WQC比所承认或预期的更为保守的现象。为了聚焦于一个规模可控的核心问题，本文剖析了美国环境保护局计算被规定为人类或动物致癌物的有机化学品提议WQC的方法。由于大多数此类化学品的结果是由人类摄入已从水柱中生物富集了这些化学品的鱼类的途径所驱动的（与人类直接摄入水的途径相反），本文专门关注从鱼类到人类的途径。这些考虑构成了一般质量保证标准和规范的基础。
