Developing environmental regulator capability in source apportionment and remediation of mine pollution

在19世纪50年代，英国是世界上领先的铅、锌和铜等贵重金属生产国。经济衰退和在国外发现更大的金属矿床迫使大多数金属矿山在20世纪20年代关闭。然而，这些废弃矿山产生的固体废物和受污染的排水仍然是今天水质和生态系统退化的主要原因，在该行业衰落近一百年后。这个问题在威尔士尤为严重，超过1300个已知的废弃矿井导致19%的河流达不到环境标准。首先，我们需要开发方法来系统地筛选受采矿影响的河流集水区，以准确识别和量化污染源，从而优先考虑修复地点。第二，我们需要开发建模工具，以便从改善水质的角度评估不同补救办法（如矿井水处理）的潜在有效性。第三，我们需要开发新的方法来处理、隔离或消除已确定的矿山污染源。本项目通过分别在威尔士中部和北部的Nant Cwmnewbandion和Afon Crafnant流域进行案例研究，阐述了其中的前两项创新。矿山污染源识别需要同步测量径流和金属浓度，以计算河流金属负荷。对河流集水区的多金属含量的估计提供了对地雷污染源的总体（或概括）评估。对流域内河流金属负荷的测量越多，就可以提取更多关于矿山污染源的详细信息，用于补救规划。然而，威尔士自然资源部（和其他环境监管机构）目前用于确定地雷污染源的方法没有提供必要的空间细节，无法涵盖整个流域的所有可能的地雷污染源。为了克服这个问题，该项目将展示一种创新的方法，以以前无法实现的空间分辨率确定污染源。具体而言，该项目将使用注入河流的水文示踪剂来计算河流金属负荷。使用示踪剂的主要优点是，它提供了数量级的提高，可以收集的样本的准确性和数量，因此提供了空间的详细程度所需的精确定位污染源。创新（2）目前在英国没有方法来评估不同的矿山污染整治方案的潜在有效性。部分原因是缺乏运行补救模型所需的适当数据。该项目将展示如何利用水文示踪研究得出的数据开发一种能够模拟假设补救方案对水质影响的建模工具。这将确保补救计划的设计和目标，以产生最大的环境和经济效益可能。该项目是自然资源威尔士（NRW）和利物浦约翰摩尔大学之间的合作努力，并建立在以前的RCUK资助的研究（NE/M017486/1; FENAC/2016/11/008; Diamond SP17227）广泛关注改善受采矿影响的集水区的水质。其主要目的是发展北威州在使用水文示踪剂和补救建模方面的专业知识，以便他们能够优先考虑将提供最大环境和经济效益的矿区进行补救。据估计，清理被矿山废物污染的河流可以在25年内通过以下方式使威尔士经济受益3000万至4900万英镑：增加娱乐活动（如捕鱼）;旅游业;提高公共供应，农业，工业和发电的水质;创造就业机会;以及提供国家和国际研究机会。

In the 1850s, the UK was the world's leading producer of valuable metals such as lead, zinc and copper. Economic downturn and the discovery of larger metal deposits abroad forced the closure of most metal mines by the 1920s. However, solid waste and polluted drainage from these abandoned mines remains a major cause of water quality and ecosystem degradation today, almost one hundred years after the decline of this industry. The problem is particularly acute in Wales where over 1300 known abandoned mines cause up to 19% of rivers to fail environmental standards.Three major innovations are required to tackle this problem. First, we need to develop methods to systematically screen mining-impacted river catchments to accurately identify and quantify sources of pollution in order to prioritise sites for remediation. Second, we need to develop modelling tools that allow the potential effectiveness of different remedial approaches (such as mine water treatment) to be evaluated in terms of improvements to water quality. Third, we need to develop novel approaches to treat, isolate or remove identified sources of mine pollution. This project addresses the first two of these innovations through case studies in the Nant Cwmnewyddion and Afon Crafnant catchments in central and north Wales, respectively.Innovation (1). Source identification of mine pollution requires synchronous measures of streamflow and metal concentrations in order to calculate stream metal loads. Multiple metal loading estimates across a river catchment provides an overview (or synoptic) assessment of mine pollution sources. The more measurements of stream metal loads across a catchment, the more detail on mine pollution sources can be extracted for remediation planning. However, the current approach used by Natural Resources Wales (and other environmental regulators) for identifying sources of mine pollution does not provide the necessary spatial detail to capture all possible sources of mine pollution across a catchment. To overcome this issue, this project will demonstrate an innovative approach for identifying sources of pollution at a previously unachievable spatial resolution. Specifically, the project will use a hydrologic tracer injected into the river to calculate stream metal loads. The major advantage of using a tracer is that it provides order-of-magnitude improvements in the accuracy and number of samples that can be collected and therefore delivers the level of spatial detail required to pinpoint sources of pollution.Innovation (2) There is currently no method in the UK for evaluating the potential effectiveness of different mine pollution remediation scenarios. This is partly due to the lack of appropriate data required to run remediation models. This project will demonstrate how data derived from hydrologic tracer studies can be used to develop a modelling tool capable of simulating the effect of hypothetical remediation scenarios on water quality. This will ensure that remediation schemes are designed and targeted to yield the most environmental and economic benefit possible.This project is a collaborative effort between Natural Resources Wales (NRW) and Liverpool John Moores University and builds on previous RCUK-funded research (NE/M017486/1; FENAC/2016/11/008; Diamond SP17227) broadly concerned with improving water quality in mining-impacted catchments. The key aim is to develop NRW expertise in the use of hydrologic tracers and remediation modelling so that they can prioritise those mine sites for remediation that will deliver the most environmental and economic benefit. It is estimated that cleaning up rivers polluted by mine wastes could benefit the Welsh economy by £30-£49M over 25 years through: increased recreational activity (e.g. fishing); tourism; enhanced water quality for public supply, agriculture, industry and power generation; job creation; and by providing national and international research opportunities.