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Weir building: A potential cost-effective method for reducing mercury leaching from abandoned mining tailings
Xiaohang Xu1, Chunhao Gu2, Xinbin Feng2
1State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China.
The Science of the Total Environment
|September 19, 2018
Summary
A weir effectively reduced mercury (Hg) pollution by capturing 40.4% of total Hg and 38.4% of methylmercury (MeHg) from a mining-impacted river. This shows weirs are a promising, cost-effective solution for mitigating mercury contamination.
Area of Science:
- Environmental Science
- Geochemistry
- Water Resource Management
Background:
- Mercury (Hg) mining poses significant environmental risks, contaminating river systems with toxic leachate.
- The Yanwuping Hg mine slagheap has led to substantial mercury pollution in the local river system.
- Understanding mercury transport dynamics is crucial for effective pollution mitigation.
Purpose of the Study:
- To evaluate the efficiency of a newly designed weir in reducing mercury pollution.
- To assess the impact of a weir on mercury species transport in a mining-affected river.
- To determine the percentage of total mercury (THg) and methylmercury (TMeHg) retained by the weir.
Main Methods:
- Conducted a year-long monitoring of mercury species in river water.
- Analyzed mercury concentrations in relation to water flow and seasonal changes (wet vs. dry seasons).
- Quantified the amount of THg and TMeHg released from the slagheap and retained by the weir.
Main Results:
- Mercury concentrations were significantly higher during the wet season, with water flow identified as the primary driver of mercury mobilization.
- Storm events were found to be major contributors to mercury release.
- The weir successfully retained approximately 412 µg THg and 4.04 µg TMeHg, achieving an annual retention rate of 40.4% for THg and 38.4% for TMeHg.
Conclusions:
- Weir construction is a potentially cost-effective measure for mitigating mercury pollution in rivers.
- The weir demonstrated significant efficiency in reducing downstream mercury transport.
- Further optimization and wider implementation of weir technology are recommended for mercury-polluted river systems.
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