Maslia M L, Aral M M, Williams R C, Williams-Fleetwood S, Hayes L C, Wilder L C
Agency for Toxic Substances and Disease Registry (ATSDR), Atlanta, Georgia, USA.
Toxicol Ind Health. 1996 Mar-Apr;12(2):139-52.
In this study, a type frequently encountered by ATSDR, groundwater and surface-water contamination have occurred near the Gratuity Road site in the town of Groton, Massachusetts. A petitioned public health assessment for the Gratuity Road site identified the primary contaminants as trichloro-ethylene (TCE), 1,1,1-trichloroethane (TCA), hexavalent chromium (Cr+6), chromium (Cr), and lead (Pb) (ATSDR 1992). The health assessment also indicated that off-site residential groundwater wells had been contaminated with TCE and TCA. Because direct measures of historical exposure to TCE are unavailable for the Gratuity Road site, computational models were used to reconstruct and predict exposure to TCE. These computational models included environmental transport and exposure models. For the environmental transport models, numerical methods were used to approximate the equations of groundwater flow and contaminant transport. Results of using environmental transport models provided us with the spatial and temporal database necessary to conduct an exposure analysis. This database indicated that groundwater concentrations of TCE typically exceeded EPA's MCL of 5 ppb for TCE. The study demonstrated that although a hazardous waste site can be remediated, nearby populations may experience significant exposure because of historical contamination, which will not be captured by remediation activities. The exposure analysis used simulated concentrations of TCE predicted by environmental transport models. These concentrations were used to compare exposure to TCE from inhalation in a one-compartment model shower with exposure from ingestion of domestic water contaminated by TCE. The exposure model indicated that exposure to TCE by the inhalation route during showering is nearly identical to exposure by ingestion of domestic water supplies contaminated with TCE. As a result, entry by inhalation route is as important as entry by ingestion route when conducting exposure analyses of contamination from volatile organic compounds such as TCE.
在本研究中，美国毒物与疾病登记署（ATSDR）经常遇到的一种情况是，马萨诸塞州格罗顿镇酬金路（Gratuity Road）附近发生了地下水和地表水污染。一份针对酬金路场地的公众健康评估请愿书确定主要污染物为三氯乙烯（TCE）、1,1,1-三氯乙烷（TCA）、六价铬（Cr+6）、铬（Cr）和铅（Pb）（ATSDR，1992年）。健康评估还表明，场外住宅地下水井已被TCE和TCA污染。由于无法获得酬金路场地历史接触TCE的直接测量数据，因此使用计算模型来重建和预测对TCE的接触。这些计算模型包括环境迁移和接触模型。对于环境迁移模型，使用数值方法来近似地下水流动和污染物迁移方程。使用环境迁移模型的结果为我们提供了进行接触分析所需的时空数据库。该数据库表明，TCE的地下水浓度通常超过美国环境保护局（EPA）规定的5 ppb的最大污染物浓度（MCL）。该研究表明，尽管危险废物场地可以得到修复，但由于历史污染，附近居民可能会受到显著接触，而修复活动无法捕捉到这种污染。接触分析使用了环境迁移模型预测的TCE模拟浓度。这些浓度用于比较在单室模型淋浴中通过吸入接触TCE与通过摄入受TCE污染的生活用水接触TCE的情况。接触模型表明，淋浴期间通过吸入途径接触TCE与通过摄入受TCE污染的生活用水接触TCE几乎相同。因此，在对TCE等挥发性有机化合物污染进行接触分析时，吸入途径的进入与摄入途径的进入同样重要。
