Identifying public water facilities with low spatial variability of disinfection by-products for epidemiological investigations
Identifying public water facilities with low spatial variability of disinfection by-products for epidemiological investigations
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DOI：
10.1136/oem.2004.017798
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发表时间：
2005-07-01
影响因子：
4.9
通讯作者：
Reif, JS
中科院分区：
文献类型：
--
作者：
Hinckley, AF;Bachand, AM;Reif, JS
背景与目的：消毒副产物（DBPs）和生殖结果的流行病学研究受到了错误分类的影响。在迄今为止进行的大多数流行病学研究中，生活在供水系统边界内的所有人都根据整个设施的三卤甲烷（THM）浓度平均值分配了一个共同的接触值。由于THM在整个配电系统中的发展并不均匀，因此分配整个设施的平均值可能不合适。一种方法，以减轻这种潜在的错误分类是选择社区的流行病学调查服务的分配系统，具有一贯的低空间变异性THMs.Methods和结果：进行了可行性研究，以开发社区选择的方法，使用信息收集规则（ICR）数据库，由美国环境保护局组装。ICR数据库包含1997年至1998年期间从198个公共供水设施（最低服务人口为10万人）的分配系统收集的每季度DBP浓度。使用两种方法确定了具有低空间变异性的THMs设施;基于一种或两种方法，发现33个设施具有低空间变异性。由于溴化三卤甲烷可能是不良生殖结果风险的重要预测因子，因此根据溴化三卤甲烷物种的比例和平均TTHM浓度将研究地点分为三个暴露概况。三卤甲烷和卤乙酸（哈斯）在这些设施之间的相关性进行了评价，看看是否选择总三卤甲烷（TTHMs）对应于低空间变异性哈斯。TTHM只有中度相关的哈斯（r = 0.623）。结论：结果提供了一个简单的方法，先验选择的网站，从国家或国家公共供水设施数据集的空间变异性低，以减少暴露误分类的DBPs的流行病学研究。
Background and Aims: Epidemiological studies of disinfection by-products (DBPs) and reproductive outcomes have been hampered by misclassification of exposure. In most epidemiological studies conducted to date, all persons living within the boundaries of a water distribution system have been assigned a common exposure value based on facility-wide averages of trihalomethane (THM) concentrations. Since THMs do not develop uniformly throughout a distribution system, assignment of facility-wide averages may be inappropriate. One approach to mitigate this potential for misclassification is to select communities for epidemiological investigations that are served by distribution systems with consistently low spatial variability of THMs.Methods and Results: A feasibility study was conducted to develop methods for community selection using the Information Collection Rule (ICR) database, assembled by the US Environmental Protection Agency. The ICR database contains quarterly DBP concentrations collected between 1997 and 1998 from the distribution systems of 198 public water facilities with minimum service populations of 100 000 persons. Facilities with low spatial variation of THMs were identified using two methods; 33 facilities were found with low spatial variability based on one or both methods. Because brominated THMs may be important predictors of risk for adverse reproductive outcomes, sites were categorised into three exposure profiles according to proportion of brominated THM species and average TTHM concentration. The correlation between THMs and haloacetic acids (HAAs) in these facilities was evaluated to see whether selection by total trihalomethanes (TTHMs) corresponds to low spatial variability for HAAs. TTHMs were only moderately correlated with HAAs (r = 0.623).Conclusions: Results provide a simple method for a priori selection of sites with low spatial variability from state or national public water facility datasets as a means to reduce exposure misclassification in epidemiological studies of DBPs.