Distribution characteristics, ecological risk assessment and source analysis of heavy metals in soil of Beizhen agricultural area, Jinzhou City, Liao Province

Objective Find out the distribution characteristics of heavy metals and provide scientific basis for local characteristic agricultural development, global tourism and soil heavy metal pollution control.Method Through Geological Investigation, soil parent material is identified, topsoil samples are collected, soil environmental quality evaluation was carried out on the basis of the distribution characteristics and enrichment degree of element content, the degree of heavy metal pollution was evaluated by 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, and further by pearson correlation analysis and cluster analysis to quantitatively determining main sources of different heavy metals.Results The results showed that the average value of Cr and Pb in the soil of Beizhen agricultural area was lower than the background value of Liaohe River Basin in Liaoning Province. The enrichment degree of heavy metals in topsoil rangs from large to small 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 is 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 are in a mildly polluted state, most heavy metals in soil samples were in no to mild pollution, and only Hg elements have strong to extremely strong pollution.The order of potential ecological risk of single index from high to low is Hg>Cd>As>Cu>Ni>Pb>Cr>Zn. The distribution range of potential ecological risk comprehensive index RI of surface soil in the whole region is 29.7~2358.16, with an average value of 141.9, mainly with 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 source of natural weathering of the parent rock, and Cu, Zn, Cd and Hg are affected 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 cause 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.