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

Lead Research Organisation: Liverpool John Moores University
Department Name: Natural Sciences and Psychology

Abstract

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.

Publications

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Description Identified sources of mine pollution in river watersheds

The principal sources of mine pollution in the Afon Ystwyth and Afon Towy river watersheds have been identified using a novel tracer injection and synoptic sampling methodology. This method increases data availability and accuracy which allows investigators to locate and quantify mine pollution sources at previously unattainable spatial resolution. In particular, the study has revealed the importance of groundwater sources of mine pollution that enter the river systems as diffuse drainage in the river bed. Understanding the location and magnitude of mine pollution is essential to inform mine site remediation strategies that lead to water quality improvements.

Simulated mine pollution remediation scenarios

Using the data generated from the tracer injection and synoptic sampling experiments, this study developed a water quality model to simulate the potential impact of hypothetical remediation scenarios on river water quality. The models generally indicate improvements in water quality by removal of surface mine waste sources, for example mine wastes next to the river. However, sources of mine pollution entering the rivers as diffuse groundwater continue to drive poor water quality.

Environmental regulator trained in novel research tools and methods

This study has trained staff in Natural Resources Wales in the use of advanced field and data analysis techniques for source apportionment and modelling of mine pollution. This has been achieved through field and office-based workshops. Staff in Natural Resources Wales have also achieved a greater scientific understanding of mine pollution dynamics and how to monitor mine pollution. Taken together, this training has improved the capability of Natural Resources Wales in mine pollution monitoring and management.
Exploitation Route Summary of impact
The State of Natural Resources Report for Wales has identified pollution from abandoned mines as
one of several risks to achieving social, cultural, environmental and economic well-being, as set out
in the Well-Being of Future Generations Act.11 Adoption of the tracer, synoptic sampling and
numerical modelling methodology by NRW would represent a major innovation in source
apportionment and remediation of mine pollution leading to more successful remediation schemes
and improvements in water quality potentially worth £30-£49M over 25 years to the Welsh
economy.12 The methodology is easily transferable to other mining-impacted catchments, generates
more useful datasets, and offers better value for money than existing approaches (£10-20k per site
investigation compared to £25-£40k for current outsourced monitoring studies13). It is envisaged that
this approach could form part of a toolbox of methods where SIMCAT modelling of large catchments
is used to prioritise smaller catchments for more detailed tracer, synoptic sampling and numerical
modelling investigations. Finally, it is envisaged that successful demonstration of the methodology
with NRW would lead to adoption by other environmental regulators in the UK.
Sectors Environment

URL https://www.youtube.com/watch?v=b0WTtY1Xrgk
 
Description The findings from this grant have been used to influence mine site remediation decision-making in the Afon Ystwyth and Afon Towy river catchments. Specifically, the work employed a novel field and modelling approach to improve identification of sources of mine pollution. This new information allowed the environmental regulator (Natural Resources Wales) to better prioritize sites for remediation that will deliver the best possible socio-economic and environmental benefit. This award was also use to foster knowledge exchange between academics and the environmental regulator (Natural Resources Wales). This was achieved through a series of field and office-based workshops that trained the regulator in the use of novel mine pollution source apportionment techniques. The impact that was achieved was a change in scientific understanding and monitoring practice.
First Year Of Impact 2019
Sector Environment
Impact Types Policy & public services

 
Description Natural Resources Wales 
Organisation Natural Resources Wales
Country United Kingdom 
Sector Public 
PI Contribution Knowledge exchange activities took place in order improve NRW staff capability in source apportionment and management of mine pollution. KE activities included office- and field-based workshops and experiments.
Collaborator Contribution The partner (NRW) facilitated access to study sites and contributed staff expertise and time to the workshop and field experiment activities.
Impact No publications as yet although several are planned and in preparation. A technical report outlining is also in preparation for NRW. This will outline the aims of the collaboration, the knowledge exchange activities undertaken, and the impact achieved. This collaboration is multi-disciplinary involving hydrologists, water quality specialists, geologists and geotechnical engineers.
Start Year 2018