Molecular structure and evolution characteristics of dissolved organic matter in groundwater near landfill: Implications of the identification of leachate leakage

Yan Ma; Zhen-Hai Liu; Bei-Dou Xi; Wen-Tao Li; Yan-Qiu Xu; Hang-Zheng Zhao; Zhu-Qi Chen; Xiao-Song He; Baoshan Xing

doi:10.1016/j.scitotenv.2021.147649

Molecular structure and evolution characteristics of dissolved organic matter in groundwater near landfill: Implications of the identification of leachate leakage

Sci Total Environ. 2021 Sep 15:787:147649. doi: 10.1016/j.scitotenv.2021.147649. Epub 2021 May 8.

Authors

Yan Ma¹, Zhen-Hai Liu², Bei-Dou Xi³, Wen-Tao Li⁴, Yan-Qiu Xu¹, Hang-Zheng Zhao¹, Zhu-Qi Chen⁵, Xiao-Song He⁶, Baoshan Xing⁷

Affiliations

¹ School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
² School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
³ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental, Beijing 100012, China.
⁴ State Key Laboratory of Pollution Control and Resources Reuse, Collaborative Innovation Center for Advanced Water Pollution Control Technology and Equipment, School of the Environment, Nanjing University, Nanjing 210023, China.
⁵ School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
⁶ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental, Beijing 100012, China. Electronic address: hexs82@126.com.
⁷ Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.

PMID: 34000547
DOI: 10.1016/j.scitotenv.2021.147649

Abstract

Landfills can cause groundwater contamination, the pollution characteristics in groundwater near landfill sites have been extensively investigated, while the rapid identification of leachate leakage remained unclear. Comprehensively characterizing dissolved organic matter (DOM) is crucial for tracing the source, species, and migration of contaminants within groundwater and protecting groundwater sources. Here, we showed that DOM composition from newer landfills was mainly composed of newly-produced tryptophan and tyrosine, and protein-like and humic-like substances were more abundant in landfills that were relatively older. DOM in landfill groundwater was initially dominated by outputs from microbial activities, followed by terrigenous input. Leaked leachate contained an additional dye-derived fluorescent matter at the excitation/emission wavelength of 240-260/440-460 nm that was absent in uncontaminated groundwater. Leachate leakage increased the concentrations of humic-like substance, DOM molecular weight, and microbial activity in the downstream groundwater, resulting in the microorganisms rapidly multiply and secrete large amounts of microbial metabolism by-products, making them suitable indicators of groundwater pollution. Three criteria were proposed to establish an interpretable fluorescence method to identify leachate pollution. The obtained results provide a novel insight into not only the monitoring, early warning, and identification but also the transport, fate and removal or transformation of groundwater leachate in landfills.

Keywords: Dissolved organic matter; Excitation–emission matrix spectra; Fluorescence method; Landfill; Leachate leakage.