This paper is the result of environmental geological survey engineering.
Objective To investigate the distribution characteristics of heavy metals and provide a scientific basis for local characteristic agricultural development, comprehensive tourism, and soil heavy metal pollution control.
Methods Through geological investigation, the soil parent material was identified, and topsoil samples were collected. Soil environmental quality evaluation was carried out based on the distribution characteristics and enrichment degree of element content. The degree of heavy metal pollution was evaluated using the ground accumulation index method. The Hakanson ecological risk index method was used to identify the degree of potential ecological risk in the study area. Furthermore, Pearson correlation analysis and cluster analysis were employed to quantitatively determine the main sources of different heavy metals.
Results The average values of Cr and Pb in the soil of the Beizhen agricultural area were lower than the background values of the Liaohe River Basin in Liaoning Province. The enrichment degree of heavy metals in the topsoil, from high to low, was Hg > As > Cd > Pb > Zn > Cu > Cr > Ni. The soil quality in the study area is generally good. The proportion of Cd, Cu, and Zn contents exceeding the risk screening values in the exceeding standard samples was 45.56%, 29.11%, and 11.47%, respectively, accounting for 86.12% of the total number of exceeding standards. The evaluation results of heavy metal pollution showed that As and Cd were in a mildly polluted state, most heavy metals in soil samples were in no to mild pollution, and only Hg elements had strong to extremely strong pollution at individual sampling points. The order of potential ecological risk of single indices from high to low is Hg > Cd > As > Cu > Ni > Pb > Cr > Zn. The distribution range of the potential ecological risk comprehensive index (RI) of surface soil in the whole region is 29.7 to 2358.16, with an average value of 141.9, primarily indicating low risk, followed by moderate risk. The results of correlation analysis and cluster analysis show that Ni, Cr, As, and Pb are mainly affected by the natural weathering of the parent rock, while Cu, Zn, Cd, and Hg are influenced by agricultural production, industrial production, transportation, and even construction activities.
Conclusions The enrichment of substances produced by the unreasonable application of agricultural substances, atmospheric deposition, industrial production, domestic garbage, and coal combustion in the soil may pose pollution risks to the ecological environment quality of the study area. In the future, it is necessary to strengthen the monitoring and research on the enrichment trend of Hg, Cd, Cu, and Zn elements in different plots.
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