Study On The Status And Health Risk Assessment Of Contaminated Sites—A Case In Abandoned Chemical Factory

Along with the rapid development of urbanization, in recent years, large numbers retired lands of industrial enterprises produced. Therefore, the related problems such as the site investigation, health risk assessment and correspnding environmetal restoration of these seriously contaminated lands have become a highlight research topic.In allusion to the retired contaminated land of a chemical plant in southern China, the paper showed an intergrated analysis of the pollution in the contaminated land and evaluation on human health risk assessment. The major contents and conclusions are shown below:(1)After investigation of the contaminated land, the seriously polluted areas in the plant were identified as the work shop, raw material and production warehouse. Chromium, lead, mercury, chloroform, carbon tetrachloride, benzene and chlorobenzene were taken as potential hazardous substances.(2)According to the methods recommended by "Technical guidelines for environmental site invetigation"(25.1-2014 HJ),38 soil sampling sites were set up in the polluted site, and 114 soil samples were collected at different depths. The results showed that heavy metal contaminations in the plant was mainly concentrated in the surface of the soil, and the volatile organic compounds were seriously polluted in the middle and lower depth of the soil in raw material production warehouse of the plant.(3)Health risk assessment was carried out for heavy metals and VOCs. The three main exposure pathways, such as oral intake, dermal contact and inhalation of soil particulate matter, were analyzed on heavy metals in surface soils. For VOCs, the main exposure pathways were oral intake, dermal contact, inhalation of soil particulate matter and inhalation gas in soils. The results showed that five kinds of pollutants in surface soil of the contaminated sites were carcinogenic. The carcinogenic risk of Cr and Pb was greater than 10-6, and the most important exposure route of Cr was inhalation of soil particles. The non carcinogenic risk of chromium in the surface was more than 1, the main exposure pathway is ingestion and dermal contact. The carcinogenic risk of chloroform and carbon tetrachloride was greater than that of 10"4 in middle and lower layer, and the main exposure pathway was inhalation of soil vapor in the middle and lower layer. In the middle and lower soil, the non carcinogenic risk of chloroform,carbon tetrachloride and chloroform were more than 1, and the main exposure route was inhalation of lower layer soil vapor in indoor air.