饮用水中的化学污染物会对人类健康造成各种不良影响，有多种方法可用于评估这些化学品的毒性。最重要的手段是流行病学和动物试验。流行病学提供了最直接、最不含糊的信息，因为它评估了暴露于化学污染物的人群中毒性影响的实际发生情况。不幸的是，流行病学的使用存在局限性。目前，动物实验测试是确定化学品毒性的最重要手段。 这些测试的一个主要限制是它们对人类适用性的不确定性。这种不确定性不仅延伸到动物和人类对化学品的定性反应的差异，而且更具体地延伸到对不同暴露水平的反应程度的差异。另外两种评估毒性的方法是短期试验，用于确定化学品在动物和人类中的致突变性和潜在致癌性，以及分子结构试验，涉及化学结构/生物活性关系的研究。 分子结构分析仍在开发中，需要进一步验证。暴露评估是毒性研究的另一个关键部分；该评估分为两类:直接测量和暴露预测。本文讨论了美国环境保护局（USEPA）用于估计人类癌症发病率的四个数学模型，这些模型可能是由于与饮用水相关的低暴露水平造成的。包括13篇参考文献。

Chemical contaminants in drinking water can cause a variety of adverse health effects in humans, and a number of means are available to assess the toxicity of these chemicals. The most important means are epidemiology and animal tests. Epidemiology provides the most direct and least ambiguous information in that it assesses the actual occurrence of toxic effects in human populations exposed to chemical contaminants. Unfortunately, there are limitations to the use of epidemiology. Currently, experimental testing of animals is the most important means available to determine the toxicity of chemicals. A major limitation of these tests is the uncertainty about their applicability to humans. This uncertainty extends not only to differences in the qualitative responses of animals and humans to chemicals but more particularly to differences in the degree of response to various exposure levels. Two other means of assessing toxicity are short-term tests, which determine a chemical's potential to be mutagenic and, potentially, carcinogenic in animals and humans, and molecular-structure tests, which involves the study of chemical structure/biological activity relationships. Molecular structure analysis is still under development and needs additional validation. Exposure assessment is another critical part of toxicity studies; this assessment falls into two categories: direct measurement and prediction of exposure. The four mathematical models used by the US Environmental Protection Agency (USEPA) to estimate the cancer incidence in humans that could result from the low levels of exposure associated with drinking water are discussed. Includes 13 references.