Analysis of heavy metal sources and spatial differentiation of health risks in agricultural soil:A case study of Duping township,Wushan county,Chongqing
[Objective]Exploring the sources and ecological risks of heavy metals in agricultural soil in the upper reaches of the Yangtze Riv-er,conducting spatial analysis of human health risks,can help propose effective suggestions for soil heavy metal pollution prevention and con-trol.[Method]45 surface soil samples(depth 0-20 cm)were collected from Duping township,Wushan county,Chongqing.Quantitative a-nalysis of the sources of soil heavy metals(Cd,Hg,Pb,As and Cr)in soil was conducted based on the principal component analysis/absolute principal component fraction(PCA/APCS)receptor model.Human health risk assessment was conducted through a human health risk as-sessment model,and spatial analysis of human health risk was conducted using geostatistics.Risk levels and influencing factors in different re-gions were given,and targeted risk control suggestions were proposed.[Result](ⅰ)The average content of Cd,Hg,Pb,As and Cr in the soil of the study area was 10.67,3.18,1.03,2.05 and 4.22 times of the background value of Chongqing soil,respectively,and the heavy metal content in the soil was significantly abnormal.(ⅱ)The proportion of priority protection,safe utilization,and strict control points for soil com-prehensive environmental quality was 2.23％,44.44％and 53.33％,respectively.The main influencing factors were Cd and Cr,and the soil was mainly acidic,which posed a high risk to the quality and safety of agricultural products and the soil ecological environment.(ⅲ)The Cd content in soil was mainly influenced by agricultural activities and parent materials,with contribution rates of 58.55％and 30.30％,respec-tively.The content of Hg and Cr in soil was mainly influenced by parent materials,with contribution rates of 71.55％and 75.41％,respec-tively.The As content in soil was mainly influenced by agricultural activities,with contribution rates of 63.12％.The Pb content in soil was mainly influenced by road traffic,with contribution rates of 90.90％.(ⅳ)The percentage of non-carcinogenic health risk index HI＞1 in a-dults was 6.67％,indicating a relatively low overall health risk.The high risk areas were concentrated in the northern and central regions of the study area,with the main influencing factor being Cr.The high contribution areas of agricultural activities and road traffic were mainly dis-tributed in the northern part of the study area.[Conclusion]It is recommended that the study area should strengthen the monitoring of agricul-tural inputs,actively carry out fertilizer reduction measures such as organic fertilizer replacement,promote the use of electric agricultural vehi-cles,and reduce the input of heavy metals into soil due to agricultural activities.
Heavy metals in soilGeostatistical methodSource apportionmentHuman health risk assessmentRisk control recommendations
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