Spatial Patterns and Risk Assessment of Heavy Metals in Soils in a Resource-Exhausted City, Northeast China

PLoS One. 2015 Sep 28;10(9):e0137694. doi: 10.1371/journal.pone.0137694. eCollection 2015.

Abstract

Northeast China is an intensive area of resource-exhausted city, which is facing the challenges of industry conversion and sustainable development. In order to evaluate the soil environmental quality influenced by mining activities over decades, the concentration and spatial distribution of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and Zinc (Zn) in surface soils (0-20cm) of a typical resource-exhausted city were investigated by analyzing 306 soil samples. The results showed that the average concentrations in the samples were 6.17 mg/kg for As, 0.19 mg/kg for Cd, 51.08 mg/kg for Cr, 23.27 mg/kg for Cu, 31.15 mg/kg for Ni, 22.17 mg/kg for Pb, and 54.21 mg/kg for Zn. Metals distribution maps produced by using the inverse distance weighted interpolation method and results revealed that all investigated metals showed distinct geographical patterns, and the concentrations were higher in urban and industrial areas than in farmland. Pearson correlation and principal component analysis showed that there were significant positive correlations (p<0.05) between all of the metals, and As, Cd, Cr, Mn, Ni, Pb, and Zn were closely associated with the first principal component (PC1), which explained 39.81% of the total variance. Cu and As were mainly associated with the second component (PC2). Based on the calculated Nemerow pollution index, percentage for slightly polluted (1<P ≤ 2) surface soils were reached 57.33%, while 42.65% topsoil samples are moderate polluted (2<P≤ 3). According to the results above-mentioned, different soil environmental function areas were classified and proper soil environmental management policy was proposed to decrease the environmental risks in the process of industrial city transformation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • China
  • Cities*
  • Environmental Pollution / analysis
  • Geography*
  • Metals, Heavy / analysis*
  • Principal Component Analysis
  • Risk Assessment*
  • Risk Factors
  • Soil / chemistry*
  • Soil Pollutants / analysis*

Substances

  • Metals, Heavy
  • Soil
  • Soil Pollutants

Grants and funding

The research was financially supported by the research fund for the National Natural Science Foundation of China (No. 21277150, 31370523, 41001340, 41201185). The authors JA and JG receive the the research fund for public welfare, granted by the Ministry of Environmental Protection of the PRC (No. 201209030). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.