Distribution,Source And Potential Ecological Risk Assessment Of Soil Heavy Metals In Poyang Lake Migratory Bird Habitat

Poyang Lake is the largest freshwater lake in my country and an internationally important wetland.The Poyang Lake National Nature Reserve provides rich food resources and a suitable living environment for various rare migratory birds,and is an important habitat for wintering migratory birds.Migratory birds will enter a large amount of feces and ruminant residues into their habitats during their habitat and foraging.Migratory birds are at the top of the Poyang Lake aquatic biological chain.Due to the biological enrichment and amplification of heavy metals in their bodies,heavy metals in the feces of migratory birds are caused.The high content has increased the accumulation of heavy metals in the soil and sediments of its habitat.However,there are currently few studies on soil heavy metal pollution and its potential ecological risks in the Poyang Lake migratory bird habitat.Therefore,paying attention to the pollution of heavy metals in the soil of the migratory bird habitat in Poyang Lake,and analyzing and discussing the source and bioavailability of heavy metals in the soil can not only provide a reference for the prevention and control of soil heavy metal pollution in the migratory bird habitat of Poyang Lake,but also provide a reference for the habitat and habitat of endangered migratory birds.The health of the population is guaranteed.In this study,the Maying Lake Wetland Migratory Bird Protection Station,the Huangjinzui beach migratory bird habitat which is in the center of lake,and the Jieshi Liujia Lake bank where there are no migratory birds were selected as the research area.Soil samples were collected in December 2019,using X-ray fluorescence spectroscopy.The content of Cr,Ni,Cu,Pb and Zn in the sample was determined.The Cd content of the sample was determined by microwave digestion-inductively coupled plasma mass spectrometry,and the heavy metal speciation of the sample was analyzed by the BCR continuous extraction method.Use the geoaccumulation index method and the enrichment factor method to evaluate the single heavy metal pollution of the soil in the study area;use the Nemerow index method and the pollution load method to evaluate the heavy metal comprehensive pollution;use the potential ecological risk index method to evaluate its potential ecology risk evaluation.The pollution degree and ecological risk based on morphology were evaluated by using the secondary phase and primary phase ratio method and the risk evaluation coding method.And through the use of correlation analysis,principal component analysis and APCS-MLR receptor model to identify and analyze its pollution sources.The main conclusions are as follows:(1)The analysis results of heavy metal content showed that the content of Cr,Ni,Cu,Pb,Zn and Cd in the Maying Lake soil ranged from 54.03～113.14 mg/kg,5.75～12.39 mg/kg,4.01～12.22 mg/kg,14.75 ～40.82 mg/kg,20.88～26.32 mg/kg and0.05～0.11mg/kg;the content of Cr,Ni,Cu,Pb,Zn and Cd in the golden mouth soil varies from 53.60 to 61.80 mg/kg,16.20 to 22.72 mg/ kg,16.55～34.99 mg/kg,67.89～105.20 mg/kg,34.42～44.17 mg/kg and 0.13～0.63mg/kg;the content of Cr,Ni,Cu,Pb,Zn and Cd in the soil of Jieshi Liujia varies within 65.02 ～75.62 mg/kg,22.44～32.54 mg/kg,20.12～55.88 mg/kg,73.82～168.53 mg/kg,28.27～47.39 mg/kg and 0.27～1.35 mg/kg.The distribution of Ni,Cu,Zn and Cd content in the soil in the study area is in the order of Jieshi Liujia>Huangjinzui>Maying Lake,the distribution of Cr content is Maying Lake>Jieshi liujia>Huangjinzui,and the order of Pb content is Huangjinzui>Jieshi Liujia>Maying lake.The Cr,Ni,Cu,Pb,and Zn in the soil of Jieshi Liujia and Huangjinzui,the Cr,Cu,and Pb in the soil of Maying Lake were higher than the background values of Poyang Lake.The Cd content in the soil of the study area is lower than the background value of Poyang Lake.(2)The evaluation results of the geoaccumulation index method showed that the soil of Maying Lake showed slight pollution of Cr and Pb,while Ni,Cu,Zn and Cd were not polluted;the soil of Huangjinzui was slightly polluted by Cu and Pb,and slightly polluted by Cu and Pb.Cr,Ni,and Zn pollution,no Cd pollution;the soil Cu pollution in Jiushiliujia is moderate,Cr,Ni,Zn,and Pb are slightly polluted,and the Cd pollution level in the study area is generally low.The evaluation result of the enrichment factor method showed that the soil Cr and Pb in Maying Lake reached a moderate pollution level,and the Ni,Cu,Zn and Cd were within the range of no-slight pollution;the Cu and Pb pollution evaluation result of the Huangjinzui soil was moderate pollution.The evaluation result of Cr,Ni,Zn,Cd pollution is no-slight pollution;the soil Cu pollution level of Jiushiliu’s house is medium-to-severe,Pb pollution level is medium,and the pollution degree of Cr,Ni,Zn and Cd is no-slight pollution.The evaluation results obtained by the geoaccumulation index method and the enrichment factor method are basically the same.The main pollutants in the soil of Maying Lake are Cr and Pb,and the main heavy metal pollutants in the soil of Huangjinzui and Jieshi Liujia are Cu and Pb.The evaluation results of Nemerrow comprehensive index method showed that the comprehensive pollution of heavy metals in the soils of Liujia and Huangjinzui in Jieshi has reached a serious level,and the soil pollution of Maying Lake is severe.The evaluation results of the pollution load index method show that the comprehensive pollution level of heavy metals in the Liujia of Jieshi is highly polluted,followed by the Huangjinzui soil,which is moderately polluted,and the Maying Lake soil is non-polluted.The order of the comprehensive pollution degree of soil heavy metals in the study area is Jishiliujia>Huangjinzui>Maying Lake.The result of potential ecological risk assessment is that the comprehensive potential ecological risks of Huangjinzui and Jieshi Liujia are both medium risks,and the main contributing factors are Cu and Pb,Cu and Cd respectively.The overall potential ecological risk level of Maying Lake is low risk.(3)The order of the proportions of Cr,Cu,Zn and Cd in Maying Lake soil is F4>F3>F2>F1,F4>F3>F1>F2,F4>F2>F3>F1 and F1>F4>F3 >F2,Ni and Pb in the order of F4>F2>F1>F3;Cu,Pb and Cd in Huangjinzui soil in order of F4>F2>F3>F1,F4>F1>F2>F3 And F1>F4>F2>F3,the order of the proportions of Cr,Ni and Zn forms is F4>F3>F2>F1;the order of the proportions of the forms of Ni,Cu,Pb and Cd in the soil of Jieshi Liujia is F4>F2> F3>F1,F4>F3>F2>F1,F2>F4>F3>F1 and F1>F4>F2>F3,the order of the proportions of Cr and Zn forms is F4>F2>F3>F1.The overall occurrence of Cr,Ni,Zn and Pb in the soil in the study area is mainly residue.The content of oxidizable and reducible Cu in Huangjinzui and Jieshi Liujia soils is relatively high,which are 32.73% and 21.00%,45.41% and20.66%,respectively.The soil Cu in Maying Lake is dominated by residue.The soil Cd forms of Maying Lake,Huangjinzui and Jieshi Liujia are mainly extracted from weak acid,and their content accounts for 73.71%,66.40% and 52.29% respectively.The bioavailability of soil Cd in the two migratory bird habitats is higher than that of non-migratory birds.Habitat.The evaluation results of the secondary phase and primary phase ratio method showed that the pollution degree of heavy metals in the soil of Maying Lake is Cd>Cu>Ni>Pb>Zn>Cr,and the degree of Cd pollution is severe.The pollution degree of heavy metal in Huangjinzui soil is ranked as Cd>Cu>Zn>Ni>Cr>Pb,and the pollution degrees of Cd and Cu are severe and light respectively.The pollution degree of heavy metals in the soil of Jieshi Liujia is Cd>Cu>Zn>Ni>Pb>Cr,and both Cd and Cu pollution are severe.The evaluation results of the risk evaluation coding method show that the soil Ni and Cu of Maying Lake are at medium risk,Cd is at high risk,and Cr,Ni and Pb are at low risk.Cd in Huangjinzui and Jieshi Liujia soil are high risk,and Cr,Ni,Cu,Pb and Zn are low risk.(4)The content of Cr,Ni,Cu,Pb,Zn,and Cd in the surface soil of the study area was used to identify the pollution sources by correlation analysis and principal component analysis,and the APCS-MLR receptor model was used to analyze the pollution sources.The results show that the heavy metal content in the study area is significantly interfered by man-made sources.Cu,Pb,Zn,and Cd may come from wastewater and slag discharged from the upstream mining industry,and Ni may come from oil leakage caused by ship transportation and fishing activities.The source of Cr may be natural phenomena such as the soil parent material or the weathering and fragmentation of the parent rock.