Study On The Selection Of Soil Risk Screening Values For Typical Industrial Contaminated Sites In Hebei

Hebei Province is heavily engaged in industrial activities,high-polluting industries comprise a significant part,such as chemical industry,pharmaceutical industry,coking industry,and textiles industry.With the national policy of Suppress the Second Industry and Develop the Third Industry being pushed forward,a large number of potential contaminated sites have emerged.Based on the requirements of both administration and environmental management,the original industrial sites should be shut down,transferred to different usage,or relocated,meanwhile the environmental risk assessment should be undertaken.The soil screening value is an important parameter of the environmental risk assessment to determine whether the further step evaluation should be taken.During the site environment investigation and risk assessment,the Beijing local standard Site Soil Environmental Risk Assessment Screening Value and United States EPA General Soil Screening Value have been adopted in Hebei Province,which partly solved the problem of absence of basic standards or technical specifications in the process of site environmental assessment.However the adoption of the standards elsewhere is not fully applicable,rational,and practicable in Hebei Province.According to the international best practice,exposure scenarios are set up by different type of land usage in order to calculate the soil screening value.This paper proposed the investigation of selecting the soil screening value on factors with high soil environmental impacts through screening and classifying the priority pollutants list domestic and overseas according to the characteristic and frequency of pollutant factors.The investigation has taken into account the characters of local sites in Hebei Province and the detected typical pollutants in current industrial soil sites.The RBCA software developed by GSI,United States was adopted in this investigation.The models used include: RBCA model,surface soil volatilization model,Johnson & Ettinger model and DED model.Localization settings were used in a series of parameters of the models including internal exposure pathway parameters of the models,exposed population parameters,site(air)exposure parameters,site(soil,groundwater)parameters etc.63 pollutants were selected in typical industries being classified into metals and inorganic,volatile organic compounds,and semi-volatile organic compounds,and were calculated with risk value based on the site types,such as resident land,park and grass land,and industrial sites.The calculatedvalues were compared and analyzed with the corresponding standard values in the Site Soil Environmental Risk Assessment Screening Value issued by Beijing Municipal Government and the US EPA,especially on the high influence factors during actual calculation process.This paper further proposes the optimization requirements combining the background value of soil environment,the detection limit of the method,and the comparison and revision of relevant foreign standards.The investigation explored deeply on selection of indicators,parameter setting,numerical calculation and index optimization,in order to promote the local determine process on selecting soil risk screening value.