Swistock Bryan R, Sharpe William E
School of Forest Resources, Pennsylvania State University, University Park, PA 16802, USA.
J Environ Health. 2005 Sep;68(2):17-22, 36.
Pennsylvania has a large population that relies on private water wells, but no statewide regulations govern the location or construction of the wells. Bacterial contamination occurs in nearly half of these water supplies, representing a health risk to rural residents. The role of large-scale aquifer contamination versus wellhead contamination from poor construction is poorly understood. The authors disinfected and installed sanitary well caps on 16 wells that contained coliform bacteria and retested them after 30-60 days and one year. Coliform bacteria were present in seven of the 16 wells within 30-60 days and all but two wells within one year. The occurrence and prevalence of bacteria in wells appeared to be influenced by weather conditions during the study. The few wells where disinfection and installation of a sanitary well cap were successful had low initial coliform bacteria and no E. coli. Samples were also collected from 24 new wells that were constructed with a grout seal and sanitary well cap. Twenty-nine percent contained coliform bacteria, and 17 percent contained E. coli. The results from this limited number of wells suggest that bacterial contamination of private wells in Pennsylvania may often originate from areas away from the wellhead.
宾夕法尼亚州有大量人口依赖私人水井，但该州没有关于水井选址或建造的全州性法规。近一半的这些供水水源受到细菌污染，这对农村居民构成了健康风险。对于大规模含水层污染与因建造不当导致的井口污染所起的作用，人们了解甚少。作者对16口含有大肠菌群的水井进行了消毒并安装了卫生井盖，在30至60天以及一年后对它们重新进行了检测。在30至60天内，16口水井中有7口检测出大肠菌群，一年后除了两口井之外其他所有水井都检测出大肠菌群。水井中细菌的出现和流行似乎受到研究期间天气状况的影响。少数成功进行消毒并安装卫生井盖的水井最初的大肠菌群含量较低且没有大肠杆菌。还从24口采用灌浆密封和卫生井盖建造的新水井中采集了样本。29%的样本含有大肠菌群，17%的样本含有大肠杆菌。来自这数量有限的水井的结果表明，宾夕法尼亚州私人水井的细菌污染可能常常源自井口以外的区域。
