Investigation And Risk Assessment Of Coal Tar Contaminated Site In A Ceramic Factory In Gansu

With the development of the national economy,domestic living conditions are improved accordingly.Driven by the acceleration of urbanization and the strong demand for decoration,China's ceramic industry has boomed rapidly,which stimulates new ceramics construction.However,soil and groundwater at the site are heavily contaminated by coal tar generated in the process of producing hydrogen gas from coal as a heat source in the ceramics manufacturing process due to backward technology,issue of natural gas supply and lack of effective supervision.This level of contamination without remediation will pose a threat to human and ecological health.Therefore,it is necessary to conduct a site investigation and risk assessment on coal tar contaminated sites in the ceramics manufacturing industry,and put forward repair suggestions.In this study,a soil and groundwater investigation and human health risk assessment were conducted on a typical coal gasification site of a ceramic factory in the Northwest of China.The main results are as follows:?1?There is a certain degree of pollution of petroleum hydrocarbons,Volatile Organic Compounds?VOCs?and semi-volatile organic compounds?SVOCs?in the soil of the contaminated site.The concentration of total petroleum hydrocarbons is relatively high and shows obvious regularity in the soil,among which the pollution in the northern district is more serious than that in the south district.The pollution of SVOCs in the site soil is more scattered.Among them,there are many types of pollutants in the gas station in the northern district,which are seriously polluted due to the variety of pollutants and the multiple of exceeding the standard large.The phenanthrene,phenol,benzo?a?pyrene and 7,12-dimethylbenzo?a?pyrene in the site soil have high environmental and health risks,and risk assessment must be initiated.?2?The main pollution source of the contaminated site is the secondary pollution source,that is,the soil pollution caused by the leakage of the facilities such as the wastewater pool,sedimentation tank and the tar pool in the production process of the enterprise.The main pollutants concerned are petroleum hydrocarbons and SVOCs such as phenol,naphthalene,fluorene,phenanthrene,anthracene,benzo?a?anthracene,benzo?b?fluoranthene,benzo?a?pyrene,indeno?1,2,3-cd?pyrene,dibenzo?a,H?anthracene and benzo?g,h,i?perylene.?3?There are some carcinogenic and non-carcinogenic risks in the polluted soil.The carcinogenic risk of naphthalene,benzo?a?anthracene,benzo?b?fluoranthene,benzo?a?pyrene,indeno?1,2,3-cd?pyrene and dibenzo?a,h?anthracene in soil exceeded the acceptable level by 10^-6.The non-carcinogenic hazard of naphthalene in the soil exceeds the acceptable hazard quotient 1.?4?The risk control values based on carcinogenic effect in the pollution sites are naphthalene>benzo?a?anthracene>benzo?b?fluoranthene>indeno?1,2,3-cd?pyrene>dibenzo?a,h?anthracene>benzo?a?pyrene.The risk control values based on non-carcinogenic effect are anthracene>phenol>fluorene>naphthalene.The comprehensive risk control value of carcinogenic effect and the comprehensive risk control value of the non-carcinogenic effect of pollutants are not more than the first-class land screening value in the standard for soil pollution risk control of soil environmental quality construction land?GB36600-2018?.?5?There are some potential ecological risks of heavy metals in polluted soil.The potential ecological risk of heavy metal pollution is"medium",and the risk level is from high to low as mercury?Hg?,cadmium?Cd?,lead?Pb?,arsenic?As?,copper?Cu?,nickel?Ni?,chromium?Cr?,zinc?Zn?.Among them,the risk levels of Hg and Cd are“heavy”and“medium”respectively.