作为国家水质评估（NAWQA）计划的一部分，美国 美国地质调查局（USGS）正在进行水源水质评估（SWQAs） 描述土壤中人为有机化合物的发生和浓度 从用于供水的选定含水层中抽取的地下水。SWQA是 旨在补充联邦、州、， 以及主要关注治疗后依从性监测的地方项目。在里面 第一年，从中国约15口生产井采集水源或原水样本 对美国11个研究区域进行了大约270年的分析 包括农药、农药降解物、， 多环芳烃和挥发性有机化合物（VOCs）。 侦测- 根据这些分析结果制定的频率和浓度标准如下: 用于从最初的163口井中选择一个子集，以便在项目的第二年进行采样 学习第二年，从69口井和 对相应的成品水进行分析，以确定 在源水中检测到的化合物在成品水中检测到。 第一年抽样的初步调查结果表明，五个最常见的 检测到的化合物为异丙甲草胺、去乙基阿特拉津和含有 检测频率分别为52%、42%和37%，最高 浓度分别为每升3.6、0.3和0.4微克；杀虫剂 降解甲草胺乙烷磺酸，检测频率为33%，且 最高浓度为每升0.6微克；以及挥发性有机化合物三氯甲烷 检测频率为47%，最大浓度为13.5微克 每升。大约45%的分析成分至少检测到一次。 取样第二年的结果，重点是比较 水源水中的人为有机化合物与成品水中的浓度， 这将使NAWQA研究人员能够确定哪些化合物经常出现在 水源正在进入社区的分配系统和浓度 它们发生的时间。仅包含摘要。

As part of the National Water-Quality Assessment (NAWQA) Program, the U.S Geological Survey (USGS) is conducting Source-Water Quality Assessments (SWQAs) to characterize the occurrence and concentrations of anthropogenic organic compounds in groundwater withdrawn from selected aquifers used for water supply. SWQAs are intended to complement existing drinking water monitoring required by Federal, State, and local programs, which focus primarily on post-treatment compliance monitoring. In the first year, samples of source or raw water collected from about 15 production wells in each of 11 study areas across the United States were analyzed for about 270 anthropogenic organic compounds that include pesticides, pesticide degradates, polycyclic aromatic hydrocarbons, and volatile organic compounds (VOCs). Detection- frequency and concentration criteria developed from the results of these analyses were used to select a subset of the initial 163 wells for sampling during the second year of the study. During the second year, samples of source water from 69 wells and of the corresponding finished water were analyzed to characterize the extent to which compounds detected in source water are detected in finished water. Preliminary findings from the first year of sampling indicate that the five most frequently detected compounds were the pesticides metolachlor, deethylatrazine, and atrazine with detection frequencies of 52, 42, and 37 percent, respectively, and maximum concentrations of 3.6, 0.3, and 0.4 micrograms per liter, respectively; the pesticide degradate alachlor ethane sulfonic acid, with a detection frequency of 33 percent and a maximum concentration of 0.6 micrograms per liter; and the VOC trichloromethane, with a detection frequency of 47 percent and a maximum concentration of 13.5 micrograms per liter. About 45 percent of the constituents analyzed for were detected at least once. Results from the second year of sampling, which focuses on comparing concentrations of anthropogenic organic compounds in source water to concentrations in finished water, will enable NAWQA researchers to ascertain which compounds frequently found in source water are entering the communities' distributions systems and the concentrations at which they occur. Includes abstract only.