Biogeochemical dynamics of contaminated groundwater systems

我的研究解决了保护地下水资源和管理地下水污染的实际需要。在美国，地下水修复的社会成本在未来30年内将达到惊人的2090 B。在不列颠哥伦比亚省，根据矿业总督察（温哥华Sun，2017年1月27日）的数据，未来清理废弃矿场的成本为12.7亿美元，仅育空地区的Faro矿就超过5亿美元。如果污染可以预防，或者更经济有效地补救，那么节省下来的资金可以用于其他重要的社会需求，如教育，医疗保健和经济发展。该研究计划的重点是预测矿山废石排水质量的发展框架和生物电系统的调查，以修复地下水污染。 矿山的两种主要固体废物是废石和尾矿，它们共同构成了世界上处理量最大的材料-在大型矿山，每年可产生数千万至数亿吨废石。通常，每开采出一个体积的矿石，就有4或5个体积的这种所谓的废石被爆破、拖运和堆放。废石通常含有矿物质，当这些矿物质被放置在大型废石堆中并因此暴露于氧气和水时，可以氧化（燃烧），将酸和金属释放到排水中。矿主、监管机构和当地社区都想在采矿许可和建造通常高达数百米的废物堆之前了解排水质量。通常情况下，分析师依赖于短时间（50 - 100周）和小规模的测试（~500克100公斤），并试图将结果外推到数十亿公斤废石的未来几十年或几个世纪。我的计划的一个组成部分是针对改善这些预测。 氧化过程本质上是电的。包括人类在内的生物体通过传递电子来呼吸（燃烧）有机碳等物质。在有氧氧化中，电子从有机物转移到氧气。在过去的十年中，已经发现介导环境中大多数氧化/还原反应的地下细菌可以将电子转移到电极。从概念上讲，电极可以作为细菌的呼吸管，使它们能够在没有氧气的环境中氧化污染物，就好像它们实际上呼吸氧气一样。对于细菌来说，这使它们能够比没有电极的情况下更迅速和更有力地氧化物质。我的工作是利用这种现象来氧化不含氧气的地下水中的有机污染物，有机物可以长时间存在。这些环境令人惊讶地普遍。温哥华附近的弗雷泽河沿着有几个地点受到这种污染。生物电方法在不列颠哥伦比亚省和加拿大修复地下水方面有很大的希望。

My research addresses the practical need to protect groundwater resources and manage groundwater contamination. The societal costs for groundwater remediation are staggering an estimated $209 B in the USA over the next 30 years. In BC, the future cost of cleanup for abandoned mine sites is $1.27 billion according to the Chief Inspector of Mines (Vancouver Sun, Jan. 27, 2017) and greater than $500 M at the Faro Mine in the Yukon alone. If contamination can be prevented, or more cost-effectively remediated, then the savings can flow to other important societal needs such as education, healthcare and economic development. This research program focuses on the development framework to predict the quality of drainage from waste rock at mine sites and the investigation of bioelectric systems to remediate groundwater contamination. The two principal solid wastes at mine sites are waste rock and tailings, which together comprise the largest volume of materials handled in the world - at large mines, tens to hundreds of millions of tons of waste rock can be produced each year. Typically 4 or 5 volumes of this so-called waste rock is blasted, hauled and placed in piles for every volume of ore mined. The waste rock often contains minerals that when placed in large waste-rock piles and are thereby exposed to oxygen and water can oxidize (burn) releasing acid and metals into drainage. Mine owners, regulators and local communities would like to know the quality of the drainage before the mine is permitted and the waste piles, often several hundred meters tall, are built. Typically, analysts rely on short duration (50 100 wks) and small-scale tests (~500 g 100 kg) and try to extrapolate results to decades or centuries in the future for billions of kg of waste rock. One component of my program is directed at improving these predictions. Oxidation processes are electric in nature. Living organisms, including humans, respire (burn) substances such as organic carbon by transferring electrons. In aerobic oxidation, electrons are transferred from organic matter to oxygen. In the last decade, it has been discovered that bacterial in the subsurface, which mediate most oxidation/reduction reactions in the environment, can transfer electrons to electrodes. Conceptually, electrodes can act as snorkels for bacteria, allowing them to oxidize contaminants in environments with no oxygen, as if they were, in effect, breathing oxygen. For bacteria, this allows them to oxidize substances more rapidly and vigorously than in absence of the electrode. My work looks to use this phenomenon to oxidize organic contaminants in groundwater that contains no oxygen, where organics can persist for long periods. These environments are surprisingly common. There are several sites along the Fraser River near Vancouver with this type of contamination. Bioelectric approaches hold great promise to remediate groundwater in BC and Canada.