Effects Of Heavy Metals In The Ganquanpu Region On The Surrounding Ecological Environment

The development of enterprises in the Ganquanpu region had led to the development of the region’s economy,which had become the backbone of the region’s economy.At the same time,the chlor-alkali industry,metal smelting and other chemical industries in the Ganquanpu region may produce heavy metals,which harm the soil and vegetation,reduce the quality of agricultural products,threaten human health and have a negative impact on the ecological environment around the area.Therefore,it was important to clarify the distribution characteristics and potential ecological risks of heavy metals in soils and plants in and around the Ganquanpu region for the environmental management of the region.In this paper,we measured the contents of As,Cr,Cd,Hg,Pb,Cu,Zn and Ni in the above-ground and below-ground samples of soil and plants in the study area,analyzed the eight restricted heavy metals in soil and plants,and clarified the distribution of heavy metals in the samples.The risk of soil heavy metals in the study area was scientifically evaluated using the ground accumulation index method,the Némero integrated index method and the pollution load index method,combined with the ecological risk index method to clarify the potential ecological risk in the area,and the health risk evaluation model was used to reveal the potential health risk that soil heavy metals may pose to humans.The correlation analysis method and principal component analysis method were used to identify the possible sources of soil heavy metals.By means of enrichment coefficient,comparison with super-enriched plants and transport coefficient,the distribution pattern of heavy metals in soil-plants and the enrichment and transport capacity of dominant plants for eight heavy metals were clarified.With reference to the limit values in GB2762-2017 and NY861-2004standards,the single-factor index method and Nemero integrated index method were used to evaluate the risk of plants in farmland areas,and the target hazard factor method（THQ）was applied to explore the potential risks that heavy metals in plants may bring to human health.The main findings were as follows:（1）The mean values of As,Hg,Pb,Cu,Zn,and Ni in soils did not exceed the background values of Xinjiang soils,and the mean values of Cr and Cd exceeded the background values of Xinjiang soils.The coefficients of variation of Cr,Pb,Cu,Zn,and Ni were weakly variable,and As,Cd,and Hg were moderately variable.（2）Comparing the values of heavy metals in the four regions,the values of soil As,Cr,Cd,Hg,Pb,and Zn were larger in the area around the enterprise,and the values of eight heavy metals were ranked the largest in the farmland area.the spatial distribution of Cr and Zn,Cu and Ni were similar,and the correlation analysis showed that there was a significant positive correlation between Cr,Pb,Cu,Zn,and Ni,both P<0.01,and the five had homology.Principal component analysis showed that Cr,Pb,Cu,Ni and Zn were the main component loadings of factor 1,and it was presumed that factor 1 is mainly natural source.The main component loadings of factor 2include As,Hg and Cd,and it was presumed that factor 2 is a composite source of anthropogenic and natural sources.（3）Pollution load index evaluation study area overall no pollution,four regions PLI were 0.93,0.81,1.15,0.90,farmland area for the future potential light pollution risk,other regions no pollution risk.The Némero composite index and potential ecological risk index evaluate the study area as a general potential light pollution risk and light potential ecological risk in the future.The Néméro composite index,potential ecological risk index and pollution load index evaluate the risk of soil heavy metals in four areas of the study area as,farmland（C）area>enterprise surrounding（A）area>transition zone（D）area>natural desert（B）area.The index distribution maps of the first two showed that the south-central part of the farmland area and the southwestern part of the enterprise and surrounding area in the four regions had larger values of the soil heavy metal evaluation index.（4）The non-carcinogenic risk quotient HQ and non-carcinogenic risk index HI of the eight metals in soil in all areas of the study area were less than 1 for children and adults,and there was no non-carcinogenic risk in the study area overall.The carcinogenic risk indices in all areas of the study area were in the range of 10^-4to 10^-6,which were acceptable carcinogenic risk levels.Comparing the three exposure pathways,the hand-oral pathway was the main pathway through which soil heavy metals may produce non-carcinogenic and carcinogenic health risks.The magnitude of the HI values of soil non-carcinogenic risk index for the four regions was agricultural land（C）region>around enterprises（A）region>transition zone（D）region>natural desert（B）region.The magnitude of the TCR values of the four regions were:peri-enterprise（A）>farmland（C）>transition zone（D）>natural desert（B）.（5）Plants in the study area were predominantly herbaceous.The ability of Phragmites communis to enrich and transfer Hg and Cr was higher,the ability of Karelinia caspia to enrich and transfer Hg,Cd and Zn was higher,and the ability of Halostachys caspica to enrich Hg and Cd was higher.（6）The total target risk coefficients for the four crops were greater than 1 for adults and children,and the total target risk coefficients for adults were sunflower>corn>melon>wheat and for children were sunflower>melon>corn>wheat.The contribution of As,Cr and Cu to the total target risk coefficients of children and adults was more than 73%,and As,Cr and Cu were more likely to cause potential risks to humans than the other five heavy metals in the future.Further studies are needed to clarify the degree of crop contamination risk and potential health risk in farming areas.