Impacts Of Urbanization Degree On The Accumulation Of Polyaromatic Hydrocarbons And Organochlorine Pesticides In Regional Environmental Media And Related Health Risk Assessment

Shenyang and Fushun from Hun river basin has gone through rapid urbanization more than 100 years,while Shen-Fu is a new city which is undergoing a rapid expansion.The unceasing expansion of the city,increment of the population density and change of the landuse has brought a series of environmental pollution problems.Polycyclic aromatic hydrocarbons and organochlorine pesticides are the typical persistent organic pollutants in urban and rural areas,respectively.And they were widly found in water,atmosphere,sediment and soil.PAHs and OCPs are easy to adsorbed by organic matter in soil and sediment due to their large octanol-water partition coefficient,and they stay persistent in the environment.In addition,PAHs and OCPs may causing a risk to human health through soil and food chain.Taking the relationship between the urbanization and environmental pollution into consideration,the concentration of PAHs in water,sediment and soils will be analysed in Hun river basin.The possible sources of the pollutants in the studied area will be get by using the isomer ratio and principal component analysis-multiple linear regression method.The vectorized data of urbanization factors(population density,traffic density and urban expansion distance)will be used to analyse the effect of urbanization on the accumulation of PAHs and OCPs in soils.Finally,risk assessment caused by soil exposure and food chain will be evaluated.The main purpose of this study was to give some basic data and scientific advice for the Hun river basin controls the environmental pollution during the urbanization process.The main research contents are as follows:(1)The concentration and source of PAHs in the river water,sediments and soils from the Hun river basin were investigated.The average concentration of PAHs in sediments and waters was 2467.22±2683.89 ng/g and 162.28±139.24 ng/L,respectively.PAHs in Shenyang,Shen-fu,Fushun and Backgroud sites increase with the development of the city.And concentration of PAHs in different land use is in the order of urban land>cultivated land>forest land.Results of isomer ratio and PCA-MLR indicated that PAHs in Shenyang manily from the combustion and vehicle emissions,and the rate of the source was 48.37%and 51.63%,repectivly.The combustion,petroleum spills and other sources were the main contributors in Shen-Fu region,and the rate was 66.28%,27.30%and 6.42%,respectively.The PAHs in Fushun soil were mainy from the source of combustion and petroleum spills,and the rate was 84.16%and 14.98%,respectively.The souce of PAHs in Background was mainly from the combustion.(2)The concentration and source of OCPs in the river water,sediments and soils from the Hun river basin were also investigated.The OCPs in water and sediments were dominated by HCHs and DDTs,and they were mainly from the history use.And the average concentration of ?21OCPs in Shenyang,Shen-fu,Fushun and Backgroud sites was 38.34,35.19,26.49and 3.77ng/g,respectively.The level of OCPs in different land use was in the order of:cultivated land?urban land>forest land.For the company that produced OCPs in Shenyang,the OCPs in urban also showed higher level.Results of isomer ratio and PCA-MLR indicated that OCPs in Shenyang manily from the point source and the use of lindane.The DDTs and HCHs in Shen-Fu were mainly from the use of DDTs,Industrial HCHs and the mixed use of HCB and DDTs,the contribute rate was 34.12%,31.70%and 34.18%,respectively.The source in Fushun was mainly from the use of p,p'-DDT.industrial HCHs and chemical industrial pollution,and the rate was 21.65%,49.04%and 29.31%,respectively?(3)Based on the distribution of PAHs and OCPs in different land use,the relationship between urbanization factior(including population density,traffic density and urban expansion distance)and the concentration of PAHs and OCPs in soils were anlysed by using the factor analysis,multivariate statistical method and statistical method analysis.The result showed that the OM,urban expansion distance and population density has a significant effect on the accumulation of PAHs in soils,while the OM,landuse tyoe and population density has a significant effect of the accumulation of OCPs in soils.The risk caused by OCPs was lower than that by PAHs,so with the development of the city,the larger emissions of PAHs will be discharged into the environment,the risk should be concerned.The health risk of exposure to chemical industrial soils from Shenyang and Fuhun was in the range of 10-6?10-5,it may cuase higher risk.(4)The behavior of PAHs in soil-maize system was further discussed in this research.The translocation of PAHs in maize tissues has positive relationship with log Kow less than 4.5,while negatively correlated otherwise.Redundancy analysis indicated the unexpected results that,the PAHs translocation by maize was reduced by Pb uptake,but not signifcantly afected by soil organic matters and pH.The human health caused by food chain was evaluated to represent the popution situation in the studied area,and provide some basic data for policy makers and urban planners in Hun river basin.The results showed that risk of cancer and cancer risk caused by intake the grains of maize were stay in acceptable level.But due to the different dietary structure,the risk of adults and children from rural areas is greater than that form the urban areas.Therefore,we should pay attention to the safety of the diet in rural areas.