Hemond H F
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge 02139, USA.
Environ Health Perspect. 1995 Feb;103 Suppl 1(Suppl 1):35-40. doi: 10.1289/ehp.95103s135.
The distribution and movement of arsenic was investigated on the Aberjona watershed in eastern Massachusetts for the purpose of identifying where and by what processes present and past human exposures to this element could have occurred. It was found that although most of the arsenic was originally released in the headwaters of the watershed, extensive migration had occurred, and the potential for human exposure existed far from designated hazardous waste sites. Both surface water and groundwater were found to be important transport pathways; arsenic moved between these two media at several locations in the watershed, with hydrology and concomitant redox, sorption, and alkylation processes determining the observed patterns of arsenic movement. These findings demonstrate that risk assessments or remedial investigations restricted to designated sites or properties in a watershed may yield both an inaccurate picture of the overall risks presented by a chemical and a less-than-optimum focus for remedial efforts. Since total recovery of the arsenic on this watershed is probably not feasible, cost-effective management will also depend on an adequate understanding of arsenic biogeochemistry and hydrologic transport processes at the watershed scale. Because the Aberjona Watershed is typical of many urban, industrialized areas, these results suggest that the whole watershed often defines the appropriate unit for investigation of chemical contamination in the environment.
为了确定当前和过去人类接触该元素可能发生的地点及过程，对马萨诸塞州东部的阿伯乔纳流域的砷分布和迁移情况进行了调查。研究发现，尽管大部分砷最初是在该流域的源头释放的，但已经发生了广泛的迁移，并且在远离指定危险废物场地的地方也存在人类接触的可能性。地表水和地下水都被发现是重要的传输途径；在该流域的几个地点，砷在这两种介质之间移动，水文以及随之而来的氧化还原、吸附和烷基化过程决定了观察到的砷迁移模式。这些发现表明，局限于流域内指定场地或地块的风险评估或补救调查，可能既无法准确反映化学品带来的总体风险，也无法对补救工作形成最佳关注重点。由于在该流域完全回收砷可能不可行，具有成本效益的管理还将取决于对流域尺度上砷生物地球化学和水文传输过程的充分理解。因为阿伯乔纳流域是许多城市工业化地区的典型代表，这些结果表明，整个流域通常是界定环境中化学污染调查合适单元的标准。
