Spatial Distribution Characteristics And Health Risk Assessment Of Heavy Metal In Soils In The North Of Hainan Province With High Background Value

In this study,agricultural soils,agricultural products,human urine and hair samples were collected synchronously from the northern Hainan province(Qiongbei District)concentrated on analyzing the status and distribution characteristics of heavy metals(eg.Cr,Cu,Ni,Zn,V,Mn,Co,Se,As,Hg and Cd).The existent form of heavy metal,Nemerow Index,Geo-accumulation pollution index,ArcGIS,and SPSS were applied to investigate the regulation of distribution characteristics of heavy metals.The health risk assessment model recommended by the United States Environmental Protection Agency(USEPA)was used to assess the potential health risks of heavy metals to local inhabitants(adult males,females,and children)via dietary consumption of the selected agricultural products of vegetables,fruits,rice and coarse cereals.The content of heavy metals and characteristics of age and gender of human urine and hair samples were evaluated to explore how heavy metals transfer and risk potential health,in expectations for providing data to support strategic decisions on pollution prevention in northern Hainan province.The main results of the study are summarized as followed:(1)The results indicate that there is a variety of heavy metal content exceeding the allowable limit in the soils of northern Hainan.The average contents of Cr,Cu,Ni,Zn,V,Mn,Co,and Cd are 3.80,2.64,5.65,1.57,2.57,2.04,3.04,and 1.61 times higher than the soil background value of Hainan province,respectively.And the variation of heavy metal content is also serious,especially in areas of the north of Lingao County,the southwest of Haikou City,the north of Qionghai City,and the south of Ding'an County and the east of Wenchang County.(2)There are significant differences in the accumulation capacity of heavy metals in agricultural crops in northern Hainan.Cr,Cu,Pb have higher possibilities in polluting certain agricultural products,while others have more enrichment ability to other metals including Mn,Cu,Zn,As,and Cd.(3)Vegetables and rice are mainly sources of adverse health risks for adults and children in northern Hainan,and their comprehensive risk values are significantly greater than those for grains and fruits.Compared with adults,children are more vulnerable to heavy metal intake.And there is greater carcinogenic risk of Cd and As through dietary intake and dietary exposure,while that of Pb is relatively low.(4)The content of heavy metals is generally low in the urine samples of residents of northern Hainan;the content of Cu is higher than other heavy metals;and the distribution varies from ages and genders.(5)The content of heavy metals is at a low level in the hair samples of northern Hainan residents.The median and average value of each heavy metal elements are within the normal range,while grateful difference can be found in between of different ages and genders in human hairs at each site.