Department of Geography and Earth Sciences and Center for Applied Geographic Information Science, University of North Carolina at Charlotte, Charlotte, NC 28233, USA.
Department of Public Health Sciences, University of North Carolina at Charlotte, Charlotte, NC 28233, USA.
Sci Total Environ. 2021 Mar 1;758:143701. doi: 10.1016/j.scitotenv.2020.143701. Epub 2020 Nov 23.
Public water systems must be tested frequently for coliform bacteria to determine whether other pathogens may be present, yet no testing or disinfection is required for private wells. In this paper, we identify whether well age, type of well, well depth, parcel size, and soil ratings for a leachfield can predict the probability of detecting coliform bacteria in private wells using a multivariate logistic regression model. Samples from 1163 wells were analyzed for the presence of coliform bacteria between October 2017 and October 2019 across Gaston County, North Carolina, USA. The maximum well age was 30 years, and bored wells (median age = 24 years) were older than drilled wells (median age = 19 years). Bored wells were shallower (mean depth = 18 m) compared to drilled wells (mean depth = 79 m). We found coliform bacteria in 329 samples, including 290 of 1091 drilled wells and 39 of 72 bored wells. The model results showed bored wells were 4.76 times more likely to contain bacteria compared to drilled wells. We found that the likelihood of coliform bacteria significantly increased with well age, suggesting that those constructed before well standards were enforced in 1989 may be at a higher risk. We found no significant association between poorly rated soils for a leachfield, well depth, parcel size and the likelihood of having coliform in wells. These findings can be leveraged to determine areas of concern to encourage well users to take action to reduce their risk of drinking possible pathogens in well water.
公共供水系统必须经常进行大肠菌群测试，以确定是否存在其他病原体，但私人水井则不需要进行测试或消毒。在本文中，我们使用多元逻辑回归模型来确定井龄、井类型、井深、包裹大小和渗滤场的土壤等级是否可以预测私人水井中大肠菌群的检出概率。2017 年 10 月至 2019 年 10 月期间，在美国北卡罗来纳州加斯托尼亚县对 1163 口井的样本进行了大肠菌群检测。最大井龄为 30 年，而钻孔井（中位年龄为 24 年）比钻井井（中位年龄为 19 年）更老。钻孔井较浅（平均深度为 18 米），而钻井井较深（平均深度为 79 米）。我们在 329 个样本中发现了大肠菌群，包括 1091 个钻孔井中的 290 个和 72 个钻孔井中的 39 个。模型结果表明，与钻孔井相比，钻孔井中含有细菌的可能性增加了 4.76 倍。我们发现，随着井龄的增加，大肠菌群的可能性显著增加，这表明那些在 1989 年实施井标准之前建造的井可能面临更高的风险。我们没有发现渗滤场土壤评级差、井深、包裹大小与井中存在大肠菌群的可能性之间存在显著关联。这些发现可以用来确定需要关注的地区，以鼓励井用户采取行动，降低饮用井水可能存在的病原体的风险。
