Research On Source Apportionment Of Heavy Metals In Farmland Soil At Small Scale

With the rapid development of industrialization and urbanization in China,heavy metal pollution has been brought to farmland and soil along with modernization.In particular,heavy metals in the soil migrate to agricultural products.With the transfer of food chain,they finally enter the human body and accumulate in the human body,causing harm to human health.In order to accurately understand the environmental quality of farmland soil and make preparations for the remediation of heavy metals in the soil,this paper takes three farmland pilot projects with obvious pollution sources as an example,using the receptor model and the input flux analysis method of inputs to find out the source of heavy metals pollution in farmland soil,and at the same time,to find out the best,more efficient and accurate model of ground source analysis method type.The main results of this study are as follows:(1)analysis of pollution sources was performed on 100 soil samples with geostatistics and APCS-MLR receptor model.The descriptive statistics revealed that the exceeding rate of Pb,Zn,Cu and Cd were 100%,15%,15%and 21%.The APCS-MLR and geostatistical analysis showed that the sources of pollution:PC 1 was Ni,Cr,Cu,Zn because of soil parent material.The PC2 was Pb,Zn and Cu which were mainly caused by anthropogenic mining activities.The PC3 was Cd,Zn and Cu which was mainly caused by agricultural inputs.The contribution rates of the three factors were 42.4%,30%and 27.6%,respectively.According to Nemero Synthesis Index evaluation method,the Shaoxing City Zhejiang,China is heavily polluted with heavy metals(2)taking a farmland in Jinhua as the research object,20 soils,3 soil profiles and local inputs were collected from the surface layer and middle layer of the high-speed railway near the farmland.The results show that only Cd element exceeds the standard,and other heavy metals do not exceed the standard.According to the morphological classification and soil profile analysis,Pb is the interaction of soil parent material and atmospheric dust.Zn,Cu,Cr,Ni are from soil parent material,Cd is from agricultural pollution and soil parent material.According to the bioavailability analysis,Pb and Cd are harmful.Long term monitoring of local inputs.The main pollution sources of Pb and Cd were dust fall(38.7%,38.2%)and straw returning(37.8%,48.1%)(3)100 topsoil samples were collected from a restored farmland in Jiaxing.Firstly,the PMF results of the receptor model show that Cd Cr,Ni,Cu and Pb are mainly caused by the parent material of soil formation,with a contribution rate of 45.39%;at the same time,20 surface and middle soil samples and local inputs are collected in the seriously polluted area,and the combined results with PMF show that the contribution rate of Mn,Zn and Cd is 30.33%;Cd,Pb and Zn are the atmospheric desposition.According to RSP risk assessment,the pollution of Cd is seriousIn experiment 1 and experiment 2,two source analysis methods,receptor model and input flux analysis,were used to find the source of pollution by using source identification and source analysis,and at the same time,the contribution rate of pollution source was calculated accurately.Secondly,the two methods are applied to the third experiment to verify the results of source analysis.At the same time,it provides a generalized analytical model of soil source for small-scale farmland.