Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA.
Environ Mol Mutagen. 2020 Jul;61(6):588-601. doi: 10.1002/em.22378. Epub 2020 Jun 19.
Water disinfection, primarily by chlorination, is one of the greatest achievements of public health. However, more than half a century after its introduction, studies in the 1970s reported that (a) chlorine interacted with organic matter in the water to form disinfection by-products (DBPs); (b) two DBPs, chloroform and bromoform, both trihalomethanes (THMs), were rodent carcinogens; (c) three brominated THMs were mutagenic; in six studies chlorinated drinking waters in the United States and Canada were mutagenic; and (d) in one epidemiological study there was an association between bladder cancer mortality and THM exposure. This led the U.S. Environmental Protection Agency to issue its first DBP regulation in 1979. Forty years later, >600 DBPs have been characterized, 20/22 have been shown to be rodent carcinogens, >100 have been shown to be genotoxic, and 1000s of water samples have been found to be mutagenic. Data support a hypothesis that long-term dermal/inhalation exposure to certain levels of the three brominated THMs, as well as oral exposure to the haloacetic acids, combined with a specific genotype may increase the risk for bladder cancer for a small but significant population group. Improved water-treatment methods and stricter regulations have likely reduced such risks over the years, and further reductions in potential risk are anticipated with the application of advanced water-treatment methods and wider application of drinking water regulations. This 40-year research effort is a remarkable example of sustained cooperation between academic and government scientists, along with public/private water companies, to find answers to a pressing public health question.
水消毒，主要通过氯化，是公共卫生的最大成就之一。然而，在其引入半个多世纪后，20 世纪 70 年代的研究报告称：(a) 氯与水中的有机物相互作用形成消毒副产物 (DBPs)；(b) 两种 DBPs，氯仿和溴仿，都是三卤甲烷 (THMs)，都是啮齿动物致癌物；(c) 三种溴化 THMs 具有致突变性；在六项美国和加拿大的氯化饮用水研究中，水具有致突变性；(d) 在一项流行病学研究中，膀胱癌死亡率与 THM 暴露之间存在关联。这导致美国环境保护署在 1979 年发布了其首个 DBP 法规。四十年后，已经有超过 600 种 DBPs 被描述出来，其中 20/22 种被证明是啮齿动物致癌物，超过 100 种具有遗传毒性，数千个水样被发现具有致突变性。数据支持这样一种假设，即长期皮肤/吸入接触三种溴化 THMs 的某些水平，以及口服卤乙酸，与特定基因型相结合，可能会增加一小部分但具有显著意义的人群患膀胱癌的风险。多年来，改进的水处理方法和更严格的法规可能降低了这种风险，随着先进的水处理方法的应用和饮用水法规的更广泛应用，预计潜在风险会进一步降低。这项长达 40 年的研究工作是学术界和政府科学家与公共/私营水务公司之间持续合作的一个显著例子，旨在回答一个紧迫的公共卫生问题。
