Collaborative Research: Chemical Hydrogeologic Investigations of Tungsten: Field, Laboratory, and Modeling Studies of an Emerging Environmental Contaminant

儿童白血病集群，如法伦，内华达州已初步联系到接近钨（W）的矿床和矿石加工业务。由于法伦的居民被证明在他们的系统中有很高的W身体负荷，因此有人认为W可能是儿童白血病发病率高的原因。研究表明，W可能是有毒的，可能是致癌的。了解环境中的W也很重要，因为它越来越多地被用作弹药和捕鱼砝码中铅的替代品。在这里，W的使用最初被认为是一种无毒的惰性金属，环境迁移率低，因此它是一种限制向环境中添加有毒Pb的方式。然而，W是很容易动员在环境中氧化后，很少有人知道它在环境中的地球化学，特别是，它的流动性和运输在真实的地下水流系统。本计画将探讨钨在环境中的反应与迁移的地球化学。 具体而言，该项目将评估W浓度如何随着地下水、含水层矿物、有机物和原位微生物群落之间的生物地球化学反应而沿着地下水流路径演变，从而改变地下水溶液的组成和氧化还原条件。为了进行研究，该项目将：1）测量具有氧化还原敏感参数的沿着特征良好的含水层中沿着流动路径的W浓度[例如，Fe物种，S（-II）]和其他地球化学成分，以确定如何改变溶液组成和氧化还原条件影响含水层中的W; 2）检查含水层沉积物中的固相W形态（例如，XANES，EXAFS，顺序提取）; 3）测量硫代钨酸盐络合物在硫化物水溶液中的稳定常数，以开发溶液络合模型，该模型将允许预测好氧和厌氧地下水中的W形态;以及4）组装一个概念，结合硫代钨酸盐络合物的稳定常数沿着与钨酸盐含氧阴离子的当前可用热力学数据来探测硫代钨酸盐络合物的热化学模型。W沿着地下水流路径的地球化学行为 该项目以作为重要饮用水源的原始含水层为研究对象，探讨W在含水层中的自然地球化学循环。由此产生的“基线”数据和概念模型将提供一个重要的资源，为其他研究人员研究的影响，人为来源的W在环境中。

Childhood leukemia clusters in e.g. Fallon, NV have been tentatively linked to the proximity to tungsten (W)-bearing ore deposits and ore-processing operations. Because residents of Fallon were shown to have high body-burdens of W in their systems, it has been suggested that W may be responsible for the high incidence of childhood leukemia. Studies have since shown that W can be toxic and may be carcinogenic. The need to understand W in the environment is also important due to its increasing use as a replacement for lead in ammunition and in fishing weights. Here, the use of W was originally thought to be a non-toxic, inert metal of low environmental mobility, it was thus a manner in which to limit the addition of toxic Pb to the environment. However, W is readily mobilized in the environment following oxidation and very little is actually known about its biogeochemistry in the environment, and in particular, its mobility and transport in real groundwater flow systems. This project will investigate the biogeochemistry of W reaction and transport in the environment. Specifically, the project will evaluate how W concentrations evolve along groundwater flow paths as biogeochemical reactions between groundwaters, aquifer minerals, organic matter, and in situ microbial communities, modify the groundwater solution composition and redox conditions. To conduct the study, the project will: 1) measure W concentrations along flow paths in well characterized aquifers along with redox sensitive parameters [e.g., Fe species, S(-II)], and other geochemical constituents to determine how changing solution composition and redox conditions affect W in aquifers; 2) examine solid-phase W speciation in aquifer sediments (e.g., XANES, EXAFS, sequential extractions); 3) measure stability constants for thiotungstate complexes in sulfidic aqueous solutions to develop a solution complexation model that will allow prediction of W speciation in aerobic and anaerobic groundwaters; and 4) assemble a conceptual, biogeochemical model that incorporates the stability constants for thiotungstate complexes along with the currently available thermodynamic data for the tungstate oxyanion to probe the biogeochemical behavior of W along groundwater flow paths. The project focus on pristine aquifers that are important drinking water sources to investigate the natural geochemical cycling of W in aquifers. The resulting 'baseline' data and conceptual model will provide an important resource for other investigators studying the effects of anthropogenic sourced W in the environment.