Redistribution of arsenic and other contaminants at sites in New Jersey and Maine

砷在地下的行为反映了地下水补给动力学中的氧化还原条件、与颗粒表面的相互作用、含水层中存在的特定矿物相。我们建议在两个有砷污染的超级基金地点进行实地研究，在我们调查期间，这两个地点都将接受积极的地下水处理。位于新泽西州南部的Vinland化学公司(Vicem)经历了至少数百吨废物的扩散，在过去50多年里，这些废物扩散到地表油、含水层、地下水地表水以及远离最初的含砷除草剂和杀菌剂生产设施下游的溪流、湖泊和河口沉积物中。我们的策略将主要是通过分析监测井中已经存在的示踪剂的样本，并将砷和其他氧化还原敏感物种的行为与这些变化联系起来，来检查这种改变的流动方案的4e补给动态。作为调查的一部分，我们将分析地下水中的~3H/3He、总[As]、形态Fe、Mn、NO3、SO4、O2、PO4/3-、Si(OH)4、Ph、Eh和常量元素化学。将定期收集样品，以检查对As的溶解性和地下运输的动力学的关键控制。我们将采集和分析联合湖的一系列沉积物岩心，以重建As在下游的运移历史，并估计向沉积物表面向上移动的As沉积物库存量的比例。温斯罗普(ME)垃圾填埋场将进行一套类似的地下水测量，旨在阐明对AS行为的控制。这种强烈减少的羽流的来源尚未解决，但来自周围自然土壤的动员似乎是一种很大的可能性，这表明许多其他垃圾填埋场也可能出现类似的羽流。与文兰德遗址不同，温斯罗普的水文地质非常复杂，因为水力传导性的空间变异性很大。除了~3H/3He外，我们还建议使用地球物理测量技术(探地雷达和电阻率)来更好地约束地下水流动状况。我们将通过跟踪沿垃圾填埋场下方流动路径的地球化学演变以及追踪标记有SF6的回注水的成分来研究AS动员过程。我们的研究将有助于更好地理解在从氧化到高度还原的不同地球化学条件下影响As迁移的过程。它们还可能有助于提高目前正在调查的一些超级基金地点的AS补救效率。

Arsenic behavior in the subsurface reflects redox conditions, interactions with particle surfaces, specific minerals phases present in the aquifer in the groundwater recharge dynamics. We propose field studies at two Superfund sites with As contamination, both of which will be under active groundwater treatment through the period of our investigation. The Vineland Chemical Company (ViChem) site in southern NJ, experienced dispersal of at least hundreds of tones of waste AS over five decades into surface oils, aquifer formations, groundwater surface waters, plus stream, lake, and estuary sediments far downstream from the original arsenical herbicide and fungicide production facilities. Our strategy will be to examin4e recharge dynamics of this altered flow regimen, primarily through analyzing samples from monitoring wells for tracers already present in the environment and to relate behavior of As and other redox sensitive species to those changes. As part of our investigation, we would analyze groundwater for 3H/3He, total [As], As speciation Fe, Mn, NO3, SO4, O2, PO4/3-, Si(oh)4, Ph, Eh and major element chemistry. Samples would be collected periodically, to examine critical controls on As solubility and dynamics of subsurface As transport. We will collect and analyze a series of sediment cores in Union Lake in order to reconstruct the history of As migration downstream, and to estimate the proportion of As sediment inventory mobilized upward towards the sediment surface. A similar set of groundwater measurements, directed at elucidating controls on As behavior, would be conducted at the Winthrop (ME) Landfill site. Sources of As to this strongly reducing plume are unresolved, but mobilization from surrounding natural soils appears to be a significant possibility, suggesting that similar As plumes could occur at many other landfills. Differing from the Vineland site, the hydrogeology at Winthrop is very complex due to large spatial variability of hydraulic conductivity. We propose to better constrain the groundwater flow regime by employing geophysical survey techniques (ground penetrating radar and resistivity) in addition to 3H/3He. We will study As mobilization processes by following the geochemical evolution along a flow path underneath the landfill and by tracing the compositions of a plume of re- injected water labeled with SF6. Our studies will contribute to a better understanding of the processes affecting As transport under different geochemical conditions ranging from oxidizing to highly reducing. They could potentially also contribute to an increase in efficiency of As remediation at a number of Superfund sites currently under investigation.