Mercury sources in a subterranean spontaneous combustion area
Chunhui Li1, Jiacong Sun2, Jiyan Shi2
1MOE Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, China.
Ecotoxicology and Environmental Safety
|June 17, 2020
Summary
Mercury isotopes effectively identify burning coal seams, aiding in combating coal spontaneous combustion. This research highlights their role in monitoring coal fires and understanding mercury cycling.
Area of Science:
- Environmental Science
- Geochemistry
- Analytical Chemistry
Background:
- Mercury (Hg) is a toxic, persistent, and mobile environmental contaminant.
- Coal spontaneous combustion is a widespread global issue, releasing significant amounts of Hg.
- Identifying burning coal seams is critical for effective coalfield fire suppression.
Purpose of the Study:
- To investigate the utility of mercury (Hg) isotopic ratios for identifying burning coal seams.
- To understand the Hg isotope characteristics in various environmental samples from a coal fire area.
- To assess the potential of Hg isotopes in coal fire monitoring and mercury cycling studies.
Main Methods:
- Determination of Hg isotopic ratios (δ²⁰²Hg) in coal, soil, dustfall, sand, and coal fire sponges (CFS) using multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS).
- Analysis of correlations between δ²⁰²Hg, Hg concentrations, and low-temperature ash content.
- Comparison of Hg isotope signatures between different coal seams (No. 9 and No. 10).
Main Results:
- Higher mineral content in coal seam No. 9 correlated with increased Hg concentration and more positive δ²⁰²Hg values compared to coal seam No. 10.
- Hg isotope characterizations successfully discriminated between different coal seam Hg values.
- Significant mass-dependent fractionation (MDF) of Hg isotopes was observed during coal burning.
- Burning and absorption processes significantly influenced the more negative δ²⁰²Hg values in ground surface samples.
Conclusions:
- Hg isotope analysis is a valuable tool for discriminating between different coal seams in a coalfield.
- The observed Hg isotope fractionation provides insights into coal burning processes and mercury transport.
- Incorporating Hg isotope analysis can enhance coal fire monitoring efforts and improve understanding of mercury cycling.
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