École supérieure d'aménagement du territoire, Université Laval, Pavillon Antoine Savard, Québec City, QC., Canada.
J Environ Manage. 2011 Mar;92(3):892-901. doi: 10.1016/j.jenvman.2010.10.056. Epub 2010 Nov 19.
During disinfection, chlorine reacts with organic matter present in drinking water and forms various undesirable chlorinated by-products (CBPs). This paper describes a study of the spatial variability of human health risk (i.e., cancer effects) from CBP exposure through drinking water in a specific region. The region under study involves nine drinking water distribution systems divided into several zones based on their characteristics. The spatial distribution of cancer risk (CR) was estimated using two years of data (2006-2008) on various CBP species. In this analysis, trihalomethanes (THMs) and haloacetic acids (HAAs) served as surrogates for CBPs. Three possible routes of exposure (i.e., via ingestion, inhalation and dermal contact) were considered for each selected compound. The cancer risk assessment involved estimating a unit risk (R(T)) in each zone of the selected distribution systems. A probabilistic analysis based on Monte Carlo simulations was employed. Risk assessment results showed that cancer risk varied between systems, but also within individual systems. As a result, the population of the same region was not exposed to the same risk associated with CBPs in drinking water. Unacceptable levels (i.e., R(T) > 10(-4)) for the estimated CR were determined for several zones in the studied region. This study demonstrates that a spatial-based analysis performed to represent the spatial distribution of risk estimates can be helpful in identifying suitable risk management strategies. Suggestions for improving the risk analysis procedure are also presented.
在消毒过程中，氯会与饮用水中存在的有机物发生反应，形成各种不理想的氯化副产物（CBPs）。本文描述了一项针对特定区域通过饮用水暴露于 CBP 所产生的人体健康风险（即癌症效应）的空间变异性的研究。研究区域涉及九个饮用水分配系统，根据其特征分为几个区域。使用两年（2006-2008 年）的各种 CBP 物种数据来估计癌症风险（CR）的空间分布。在该分析中，三卤甲烷（THMs）和卤乙酸（HAAs）用作 CBPs 的替代物。对于每个选定的化合物，考虑了三种可能的暴露途径（即摄入、吸入和皮肤接触）。癌症风险评估涉及在选定的分配系统的每个区域中估算单位风险（R（T））。采用基于蒙特卡罗模拟的概率分析。风险评估结果表明，癌症风险在系统之间以及在单个系统内有所不同。因此，同一地区的人口不会面临与饮用水中 CBPs 相关的相同风险。在研究区域的几个区域中确定了几个区域的不可接受水平（即 R（T）> 10（-4））。这项研究表明，进行空间分析以代表风险估计的空间分布有助于确定合适的风险管理策略。还提出了改进风险分析程序的建议。
