United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709, United States.
United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709, United States; Oak Ridge Institute for Science and Education Research Participant, 109 T.W. Alexander Drive, Research Triangle Park, NC 27709, United States.
Environ Pollut. 2018 Mar;234:297-306. doi: 10.1016/j.envpol.2017.11.033. Epub 2017 Nov 26.
Monitored contaminants in drinking water represent a small portion of the total compounds present, many of which may be relevant to human health. To understand the totality of human exposure to compounds in drinking water, broader monitoring methods are imperative. In an effort to more fully characterize the drinking water exposome, point-of-use water filtration devices (Brita filters) were employed to collect time-integrated drinking water samples in a pilot study of nine North Carolina homes. A suspect screening analysis was performed by matching high resolution mass spectra of unknown features to molecular formulas from EPA's DSSTox database. Candidate compounds with those formulas were retrieved from the EPA's CompTox Chemistry Dashboard, a recently developed data hub for approximately 720,000 compounds. To prioritize compounds into those most relevant for human health, toxicity data from the US federal collaborative Tox21 program and the EPA ToxCast program, as well as exposure estimates from EPA's ExpoCast program, were used in conjunction with sample detection frequency and abundance to calculate a "ToxPi" score for each candidate compound. From ∼15,000 molecular features in the raw data, 91 candidate compounds were ultimately grouped into the highest priority class for follow up study. Fifteen of these compounds were confirmed using analytical standards including the highest priority compound, 1,2-Benzisothiazolin-3-one, which appeared in 7 out of 9 samples. The majority of the other high priority compounds are not targets of routine monitoring, highlighting major gaps in our understanding of drinking water exposures. General product-use categories from EPA's CPCat database revealed that several of the high priority chemicals are used in industrial processes, indicating the drinking water in central North Carolina may be impacted by local industries.
监测饮用水中的污染物仅代表存在的总化合物中的一小部分，其中许多可能与人类健康有关。为了了解人类接触饮用水中化合物的总体情况，必须采用更广泛的监测方法。在一项对北卡罗来纳州 9 户家庭进行的试点研究中，使用即时水过滤设备（碧然德滤水器）收集饮用水样本，以更全面地描述饮用水暴露组。通过将未知特征的高分辨率质谱与 EPA 的 DSSTox 数据库中的分子公式相匹配，对其进行可疑筛选分析。从 EPA 的 CompTox Chemistry Dashboard 中检索到具有这些公式的候选化合物，该数据库是一个最近开发的数据中心，其中包含大约 720,000 种化合物。为了将化合物优先分为对人类健康最相关的化合物，使用了来自美国联邦合作 Tox21 计划和 EPA ToxCast 计划的毒性数据，以及 EPA 的 ExpoCast 计划的暴露估计值，结合样品检测频率和丰度，为每个候选化合物计算了“ToxPi”分数。从原始数据中的约 15,000 个分子特征中，最终将 91 种候选化合物分为最高优先级类别，以供进一步研究。其中 15 种化合物通过分析标准品得到确认，包括优先级最高的化合物 1,2-苯并异噻唑啉-3-酮，该化合物出现在 9 个样本中的 7 个中。其他高优先级化合物中的大多数都不是常规监测的目标，这突显了我们对饮用水暴露情况的理解存在重大差距。EPA 的 CPCat 数据库中的一般产品使用类别表明，一些高优先级化学品用于工业过程，这表明北卡罗来纳州中部的饮用水可能受到当地工业的影响。
