Contaminants from a former Croatian coal sludge dictate the structure of microbiota in the estuarine (Raša Bay) sediment and soil

Weiting Zhang; Qianyun Mo; Zaixing Huang; Muhammad Adnan Sabar; Gordana Medunić; Tatjana Ivošević; Huan He; Michael Urynowicz; Fang-Jing Liu; Hongguang Guo; Rizwan Haider; Muhammad Ishtiaq Ali; Asif Jamal

doi:10.3389/fmicb.2023.1126612

Contaminants from a former Croatian coal sludge dictate the structure of microbiota in the estuarine (Raša Bay) sediment and soil

Front Microbiol. 2023 Feb 9:14:1126612. doi: 10.3389/fmicb.2023.1126612. eCollection 2023.

Authors

Affiliations

¹ Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, China.
² Department of Civil and Architectural Engineering, University of Wyoming, Laramie, WY, United States.
³ Environmental Risk Control Engineering Laboratory, Division of Environmental Design, Kanazawa University, Kanazawa, Japan.
⁴ Department of Geology, Faculty of Science, University of Zagreb, Zagreb, Croatia.
⁵ Faculty of Maritime Studies, University of Rijeka, Rijeka, Croatia.
⁶ College of Safety and Emergency Management and Engineering, Taiyuan University of Technology, Taiyuan, China.
⁷ Institute of Energy & Environmental Engineering, University of the Punjab, Lahore, Pakistan.
⁸ Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan.

Abstract

Introduction: Croatian superhigh-organic-sulfur Raša coal had been mined for nearly 400 years. The release of hazardous trace elements (HTEs) and toxic organic pollutants (TOPs) into the local environment by coal mining, preparation, and combustion activities has resulted in pollution.

Methods: In this study, the diversity and composition of microbial communities in estuarine sediment and soil samples as well as community function responses to the pollutants were investigated.

Results: The results showed that PAH degradation does occur following 60 years of natural attenuation, the location is still heavily polluted by polycyclic aromatic hydrocarbons (PAHs) and HTEs. Microbial analyses have shown that high concentrations of PAHs have reduced the diversity and abundance of microbial communities. The pollution exerted an adverse, long-term impact on the microbial community structure and function in the brackish aquatic ecosystem. Microorganisms associated with the degradation of PAHs and sulfur-containing compounds have been enriched although the diversity and abundance of the microbial community have reduced. Fungi which are believed to be the main PAH degrader may play an important role initially, but the activity remains lower thereafter. It is the high concentrations of coal-derived PAHs, rather than HTEs, that have reduced the diversity and abundance of microbial communities and shaped the structure of the local microbiota.

Discussion: This study could provide a basis for the monitoring and restoration of ecosystems impacted by coal mining activities considering the expected decommission of a large number of coal plants on a global scale in the coming years due to growing global climate change concerns.

Keywords: PAHs; Raša coal; estuary; hazardous trace elements; microbial diversity; natural attenuation.

Grants and funding

This work was supported by National Key Research and Development Program of China (2019YFC1805400 and 2021YFC2902603), Fundamental Research Funds for the Central Universities of China (2021ZDPY0210 and 2022ZZCX01K1), National Natural Science Foundation of China (No. 42172187), and Key Research Development Program of in Modern Agriculture (KC21137).