Spatial distribution and ecological risk assessment of heavy metals in karst soils from the Yinjiang County, Southwest China

PeerJ. 2022 Feb 1:10:e12716. doi: 10.7717/peerj.12716. eCollection 2022.

Abstract

Background: Soil heavy metals (HMs) under different land-use types have diverse effects, which may trigger the ecological risk. To explore the potential sources of HMs in karst soils, the spatial distribution and geochemical behavior of HMs based on different land-use types are employed in this study.

Methods: Soil samples (n = 47) were collected in three suites of karst soil profiles from the secondary forest, abandoned cropland and shrubland in Yinjiang, Southwest China. The concentrations of Ni, Mn, Cr, Pb, Cd and Mo were determined to give a comprehensive understanding of the possible sources of these HMs and evaluate the potential ecological risk in Yinjiang County.

Results: The mean concentrations of HMs in all profiles followed the same order: Mn > Cr > Ni > Pb > Mo > Cd. Meanwhile, the concentrations of most HMs roughly increased with the depth. Additionally, the concentrations of HMs were mostly correlated with soil pH and SOC, rather than with clay and silt proportions. By contrast, with the enrichment factors (EF), geo-accumulation (Igeo) and potential ecological risk index (PERI) of HMs in soil under different land-use types, the results indicated that these HMs exhibited non-pollution (Igeo < 0) and no ecological risk (PERI < 30) to human health in soils of Yinjiang County.

Conclusions: The distribution of HMs is dominated by weathering in the karst area, and the effects of agricultural inputs on the enrichment of soil HMs in Yinjiang County are limited. This further state that the arrangement of the local agricultural structure is reasonable.

Keywords: Contamination assessment; Distribution characteristics; Karst area; Land-use types; Soil heavy metals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cadmium
  • China
  • Environmental Monitoring / methods
  • Humans
  • Lead
  • Metals, Heavy* / analysis
  • Risk Assessment
  • Soil / chemistry
  • Soil Pollutants* / analysis

Substances

  • Soil
  • Cadmium
  • Lead
  • Soil Pollutants
  • Metals, Heavy

Grants and funding

This work was supported jointly by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB26020502) and the National Natural Science Foundation of China (Grant Nos. 41772380 and 41673020). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.