Arsenic and mercury groundwater contamination caused by oil and gas production wastewaters in the Niger Delta Region

砷和汞是两种剧毒元素，会危害作为全球饮用水来源的地下水。根据世界卫生组织的数据，50个国家中至少有1.4亿人饮用了被砷污染的水。虽然在亚洲、南美、北美和欧洲对这两个因素进行了广泛的研究，但对非洲大陆的关注却很少。尼日尔三角洲是尼日利亚石油工业的中心。尼日利亚是非洲最大的天然气生产国，全球第六大原油出口国，拥有非洲大陆第二大石油储量。在过去的50年里，估计有1300万桶原油泄漏在尼日尔三角洲地区。由于已知砷和汞都存在于原油中或在石油泄漏过程中释放到地下水中，我们提出了关于尼日利亚产油区砷和汞的首次研究，旨在为地下水的可持续和安全利用提供重要信息。这为研究与广泛的碳氢化合物生产有关的地下水污染提供了一个独特的机会，可以将其外推到具有类似发生率的其他地点。主要目标将是了解控制地下水中砷和汞的来源、运输和归宿的过程。为了实现这一目标，将进行实地和实验室研究，以预测地下水中砷和汞浓度升高的可能性。此外，我们将评估简单但有效并可在家庭规模上部署的清除技术。这项研究有四个假设：1。将油气生产废水引入含水层可能会提高地下水中砷和汞的浓度2。如果含水层基质中含有地源性汞和砷，则可能使地下水中汞和砷的浓度增加。3 .由于自然或人为过程引入含水层的氧气氧化，从硫化物矿物（如黄铁矿）和天然有机物中动员地质汞和砷。黄铜颗粒和氧化铁的手动过滤器可去除地下水中的砷和汞。

Arsenic and mercury are two highly toxic elements that compromise groundwater as a source of drinking water globally. According to the World Health Organization, at least 140 million people in 50 countries have been drinking arsenic-contaminated water. While both elements have been studied extensively in Asia, South and North America and Europe, there has been little attention on the African continent.The Niger Delta is the heart of the petroleum industry in Nigeria. Nigeria is the largest natural gas producer in Africa, the sixth-largest crude oil exporter globally, and has the second-largest oil reserves on the African continent. Over the past 50 years, an estimated 13 million crude oil barrels have been spilled in the Niger Delta region. Since both As and Hg are known to occur in crude oil or are released into groundwater during oil spills, we propose the first study concerning As and Hg in Nigeria's oil-producing region, intending to provide crucial information for sustainable and safe use of groundwater. This presents a unique opportunity to study the groundwater contamination related to extensive hydrocarbon production, which can be extrapolated to other locations with a similar incidence.The main goal will be to understand the processes that control the source, transport and fate of As and Hg in groundwater. To reach this goal, field and laboratory studies will be carried out to predict the possibility of elevated As and Hg concentrations in groundwater. Furthermore, we will evaluate removal techniques that are simple but efficient and can be deployed at the household scale.Four hypotheses drive the study:1. Introduction of oil and gas production wastewater into the aquifer potentially elevates the concentration of As and Hg in groundwater2. A concentration increase of Hg and As in groundwater is possible if the aquifer matrix contains geogenic Hg and As.3. Mobilization of geogenic Hg and As from sulfide minerals (e.g., pyrite) and natural organic matter due to oxidation by oxygen introduced into the aquifer by either natural or anthropogenic processes.4. Manual filters of brass granule and iron oxide remove As and Hg from groundwater.