Microbial Controls on the Mobilization and Speciation of Arsenic from Newark Basin Shale

纽瓦克盆地页岩中砷的迁移和形态的微生物控制

• 批准号: 0433488
• 负责人: John Reinfelder
• 金额: $ 44.54万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-11-15 至 2009-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0433488&HistoricalAwards=false
• 关键词: Microbial; Controls; Mobilization; Speciation; Arsenic

ABSTRACT OF RESEARCHMICROBIAL CONTROLS ON THE MOBILIZATION AND SPECIATION OF ARSENIC FROM NEWARK BASIN SHALEThe North American Rift Basin spans part of New Jersey (Newark Basin) and has arsenic containing red, gray and black shale. In a recent study conducted by the NJ Geological Survey, it was determined that 15-30% of the wells from this area had arsenic levels exceeding 10 g/L and up to 215g/L. Human exposure to arsenic within the environment is typically through drinking water and the consumption of water with arsenic concentrations greater than 10 mg/L greatly increases an individual's risk of developing lung and bladder cancer (NRC, 2001). As a result, the U.S. Environmental Protection Agency (EPA) has proposed a reduction in the maximum contaminant level (MCL) for arsenic in drinking water from 50 mg/L to 10 mg/L (USEPA, 2001). Arsenic mobilization in the Newark Basin could be due to the oxidation of pyrite in black and gray shale, and/or release of arsenic from hematite or other iron oxides in red shale (Serfes et al, 2004). Although chemical and physical processes play a role in the weathering of these minerals, there is also evidence that microorganisms may be essential to the process. The hypothesis of this proposal is that microorganisms play a defining role in the mobilization and speciation of arsenic in the Newark Basin and its groundwater. Three objectives will be undertaken: 1) To compare the community structure of attached and suspended microorganisms associated with gray/black shale and with red shale found in the Newark Basin. It is hypothesized that pyrite-impacted aquifers will have a different microbial community structure than those impacted by hematite. These differences will help us identify the specific organisms critical to arsenic mobilization. 2) To examine the degree to which microbes enhance arsenic mobilization at ambient (circumneutral) pH from native pyrite and hematite. It is proposed that iron oxidizers facilitate the release of arsenic from pyrite and that iron reducers may mobilize arsenic from hematite under anoxic conditions. In addition, it is proposed that arsenic oxidizers and reducers are active in controlling the relative abundance of As(V) and As(III) and thereby affecting arsenic transport and distribution. The organisms involved in arsenic mobilization and speciation will be identified and characterized. 3) To identify iron-utilizing microbes associated with the pyrite and/or hematite shale and arsenic-utilizing microbes involved in the speciation of arsenic from the Newark Basin using biomolecular markers based on 16S rDNA sequence. Fluorescent in-situ hybridization (FISH) and scanning electron microscopy (SEM) will be used to observe the spatial distribution of both iron and arsenic active microbes on surfaces of black and red shale. It is proposed that the organisms will associate with specific minerals in the shale, for example, iron oxidizers will attach to pyrite and arsenite oxidizers will be associated with As(V)-enriched iron oxides. Understanding the role that the microbial community plays in mobilizing As from the geologic media will constitute a new contribution to our basic knowledge of biogeological weathering and trace element cycling in the earth's environment. Understanding the processes that lead to the mobilization of arsenic from naturally-enriched minerals is essential to predicting and protecting the quality of drinking water supplies. Although this project is directed at the arsenic issue in the Newark Basin in New Jersey, the Eastern Rift Basin of North America is a major formation in the mid-Atlantic and northeast region of the US and other similar sedimentary basins around the world are sources of drinking water.

微生物对纽瓦克盆地页岩中砷的活动和形态的控制北美裂谷盆地横跨新泽西州（纽瓦克盆地）的一部分，具有含砷的红色、灰色和黑色页岩。 在新泽西州地质调查局最近进行的一项研究中，确定该地区15-30%的威尔斯井的砷含量超过10 g/L，最高可达215 g/L。 人类通常通过饮用水接触环境中的砷，饮用砷浓度大于10毫克/升的水会大大增加个人患肺癌和膀胱癌的风险（NRC，2001年）。 因此，美国环境保护署（EPA）建议将饮用水中砷的最大污染物水平（MCL）从50 mg/L降至10 mg/L（USEPA，2001年）。 纽瓦克盆地的砷流动可能是由于黑色和灰色页岩中黄铁矿的氧化，和/或红色页岩中赤铁矿或其他铁氧化物中砷的释放（Serfes等人，2004年）。 虽然化学和物理过程在这些矿物的风化过程中发挥了作用，但也有证据表明微生物可能对这一过程至关重要。 该提案的假设是微生物在纽瓦克盆地及其地下水中砷的动员和形态形成中起决定性作用。 本研究的目的有三：1）比较纽瓦克盆地灰/黑色页岩和红色页岩中附着和悬浮微生物的群落结构。 据推测，黄铁矿影响的含水层将有一个不同的微生物群落结构比那些受赤铁矿影响。 这些差异将帮助我们确定对砷动员至关重要的特定生物体。 2)研究微生物在环境（中性）pH值下提高天然黄铁矿和赤铁矿中砷的动员程度。有人建议，铁氧化剂促进砷从黄铁矿中释放，铁还原剂可以动员砷从赤铁矿缺氧条件下。 此外，有人提出，砷氧化剂和还原剂是积极的控制相对丰度的As（V）和As（III），从而影响砷的运输和分配。 参与砷动员和形态的生物体将被识别和表征。 3)利用基于16 S rDNA序列的生物分子标记，对纽瓦克盆地黄铁矿和/或赤铁矿页岩中的铁利用微生物和砷形态转化中的砷利用微生物进行鉴定。 采用荧光原位杂交（FISH）和扫描电镜（SEM）技术，对黑、红页岩表面铁、砷活性微生物的空间分布进行了观察。 有人提出，生物体将与特定的矿物在页岩中，例如，铁氧化剂将附着在黄铁矿和亚砷酸盐氧化剂将与As（V）富集的铁氧化物。 了解微生物群落在动员地质介质中的作用，将构成一个新的贡献，我们在地球环境中的地质风化和微量元素循环的基础知识。 了解导致砷从天然富集矿物质中迁移的过程对于预测和保护饮用水供应的质量至关重要。 虽然该项目针对的是新泽西纽瓦克盆地的砷问题，但北美东部裂谷盆地是美国大西洋中部和东北部地区的主要地层，世界各地其他类似的沉积盆地是饮用水的来源。