Jacobs T L, Warmerdam J M, Medina M A, Piver W T
Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287, USA.
Environ Health Perspect. 1996 Aug;104(8):866-70. doi: 10.1289/ehp.96104866.
Pollutants in groundwater aquifers may constitute a significant human health risk. A large variation in response may result among human populations experiencing the same level and duration of exposure to pollutants. Variability in response, as a result of exposure to a carcinogenic contaminant such as trichloroethylene (TCE), can be represented by a distribution function of safe doses. Spatial variability in aquifer characteristics and contaminant transport parameters requires the use of stochastic transport models to quantify variability in exposure concentrations. A second moment method is used to evaluate the probability of exceeding safe dose levels for a contaminated aquifer. The name of this method stems from the fact that the formulation is based on the first and second moments of the random variables. With this method, the probability is a function of the variability of contaminant concentration (which incorporates variability in hydrogeologic parameters such as hydraulic conductivity) and the variability in response in the human population. In this manner, the severity of the health risk posed by a contaminated aquifer and the evaluation of appropriate strategies and technologies for aquifer remediation are a function of contaminant concentrations and human health risks. The applicability and limitations of this method are demonstrated with data on groundwater contaminated by TCE at Hill Air Force Base, Utah.
地下含水层中的污染物可能构成重大的人类健康风险。在接触污染物的水平和持续时间相同的人群中，反应可能会有很大差异。由于接触致癌污染物（如三氯乙烯（TCE））而导致的反应变异性，可以用安全剂量的分布函数来表示。含水层特征和污染物迁移参数的空间变异性需要使用随机迁移模型来量化暴露浓度的变异性。采用二阶矩法来评估受污染含水层超过安全剂量水平的概率。该方法的名称源于其公式基于随机变量的一阶矩和二阶矩这一事实。使用这种方法，概率是污染物浓度变异性（其中包含水文地质参数如渗透系数的变异性）和人群反应变异性的函数。通过这种方式，受污染含水层所带来的健康风险的严重程度以及对含水层修复的适当策略和技术的评估是污染物浓度和人类健康风险的函数。利用犹他州希尔空军基地受三氯乙烯污染的地下水数据，证明了该方法的适用性和局限性。
