Source Analysis of Soil Heavy Metals in Agricultural Land Around the Mining Area Based on APCS-MLR Receptor Model and Geostatistical Method

Abstract

In order to identify the source of heavy metals in the soil around a mining area and provide effective suggestions for the prevention and control of regional soil pollution, 118 topsoil samples (0-20 cm) were collected in the northern part of Wuli Township, Qianjiang District, Chongqing. The heavy metal (Cd, Hg, Pb, As, Cr, Cu, Zn, and Ni) contents in the soil and soil pH were analyzed, and the spatial distribution and sources of heavy metals in the soil were studied using the geostatistical method and APCS-MLR receptor model. The results showed that the content of heavy metals in the soil was significantly higher than the background value in Chongqing; there was obvious surface accumulation; and Hg, Pb, Cd, As, and Zn showed strong variation. The proportions of soil Cd, Hg, Pb, As, and Zn exceeding the risk screening values were 47.11%, 6.61%, 4.96%, 5.79%, and 7.44%, respectively, and the proportions of soil Cd, Hg, Pb, and As exceeding the risk control values were 0.83%, 4.13%, 0.83%, and 0.83%; thus, the problem of excessive heavy metals in the soil was significant. Soil Cd, As, Cr, Cu, and Ni were mainly affected by soil parent materials, and their contribution rates to the total soil elements were 77.65%, 68.55%, 71.98%, 90.83%, and 82.19%, respectively. Soil Hg, Pb, and Zn were mainly affected by the mining of mercury mines and lead-zinc mines, with the contribution rates of 86.59%, 88.06%, and 91.34%, respectively. In addition, agricultural activities also affected soil Cd and As contents. It is recommended to strengthen the safety monitoring of agricultural products and agricultural inputs, plant varieties with a low accumulation of heavy metals, reduce the use of livestock manure, and grow non-edible agricultural products in areas that exceed the control value of heavy metal pollution risk.