Impacts of mining activities on the spatial distribution and source apportionment of soil organic matter in a karst farmland

Jun Zhang; Rongfei Wei; Qingjun Guo

doi:10.1016/j.scitotenv.2023.163627

Impacts of mining activities on the spatial distribution and source apportionment of soil organic matter in a karst farmland

Sci Total Environ. 2023 Jul 15:882:163627. doi: 10.1016/j.scitotenv.2023.163627. Epub 2023 Apr 20.

Authors

Jun Zhang¹, Rongfei Wei², Qingjun Guo¹

Affiliations

¹ Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: weirongfei4099@126.com.

PMID: 37087010
DOI: 10.1016/j.scitotenv.2023.163627

Abstract

Worldwide mining activities produce vast quantities of mine tailings, which pose a threat to soil quality, crop yields, and the regional environment in the adjacent agricultural soil, but little is known about the impact of mining activities on the SOM source and migration. In this study, soil samples of the topsoil (0-15 cm) and soil profiles (0-50 cm), as well as the potential sources samples (C3 plants, C4 plants and mining tailings) were collected from mine-contaminated karst farmland of four different pollution levels (NP, non-polluted; SP, slightly polluted; MP, moderately polluted; and HP, heavily polluted). Total organic carbon (TOC), total organic nitrogen (TON), and stable isotopic compositions (δ¹³C_org and δ¹⁵N_org) of soil and potential sources samples were determined. In the topsoil, the concentrations of TOC (1.9 ± 1.4 %) and TON (0.1 ± 0.1 %), and the value of δ¹³C_org (-25.4 ± 0.9 ‰) and δ¹⁵N_org (-3.6 ± 3.6 ‰), were not significantly different among HP, MP and SP farmland (P > 0.05). C3 plants (42.1 %-49.9 %) and mine tailings (32.3 %-40.1 %) were identified as the dominant source of topsoil SOM. In the soil profile, TOC%, TON%, δ¹³C_org, and δ¹⁵N_org were affected by soil depth and pollution level. TOC% and TON% in the soil profiles of NP changed slightly with soil depth, while that in the other soil profiles was decreased with the increasing of soil depth. The δ¹⁵N_org value in the SP soil dropped sharply when the soil depth was >15 cm, while that in the HP and MP soil was fluctuated and no obvious vertical pattern. Our findings provide valuable information regarding the impact of mining activities on SOM distribution and source apportionment in karst farmlands. The effects of mine tailings on SOM should be considered when the soil quality was estimated in the mine-grain composite area.

Keywords: Isotopes; Lead‑zinc mine; SIMMR model; Soil profile; Topsoil.