Petroleum-Contaminated Sites Risk Assessment And Case Study

Petroleum-contaminated sites, one of the typical contaminated sites in China, were selected to research. Their priority pollutants were screened by a semi-quantitative scoring and ranking method. And the Soil Guideline Values (SGVs) of the 16-priority control polycyclic aromatic hydrocarbons (PAHs) were derived for three kinds of typical soils (red earths and fluvo-aquic soils and black soils) in China. In the end, Tiebutie contaminated site was choosed as a representative case for petroleum-contaminated sites and health risks caused by the 16-PAHs in the site were assessed.Firstly, one hundred and nine pollutants which were likely existent in petroleum-contaminated sites were selected on the basis of information investigation and contamination source analysis and reference to the black lists in the word. The pollutants were scored and ranked by the selected Chemical Scoring and Ranking Assessment Model (SCRAM) according to the determinate screen principles. Thirty-six pollutants were determinated as priority pollutants for petroleum-contaminated sites, which included 16-PAHs and 4-BETX, etc.Secondly, the UK Contaminated Land Exposure Assessment (CLEA) model was choosed to derive SGVs and estimate health risk after model comparision and applicability evaluation. The SGVs of 16-PAHs were derived with parameter-modificated CLEA model for three kinds of Chinese typical soils (red earths and fluvo-aquic soils and black soils) in the situation of different land-uses and soil organic matters. The derived SGVs were also discussed by comparing with the United States Preliminary Remediation Goals (PRGs) and Soil Screening Levels (SSLs).Finally, spatial distribution of 16-PAHs contents in the topsoil of Tiebutie petroleum-contaminated site was investigated by sampling and analysis. Health risks caused by the 16-PAHs were evaluated with parameter-modificated CLEA model and the results showed that oral intake was the most primary exposure pathway. The hazard index of each noncancer PAHs (including acenaphthene, acenaphthylene, anthracene, benzo (g,h,i) perylene, fluorathene, fluorene, naphthalene, phenathrene and pyrene) and their total hazard index were less than one, showing that their hazard was little. But the cancer risk of each cancer PAHs (including benzo (a) anthracene, benzo (a) pyrene, benzo (b) fluoranthene, chrysene, dibenzo (a,h) anthracene and indeno (1,2,3-c,d) pyrene, except for benzo (k) fluoranthene) and their total cancer risk exceeded the commonly acceptable lifetime cancer risk (10^-6). Moreover, the cancer risk of benzo (a) pyrene or dibenzo (a,h) anthracene exceeded the 10^-4 lifetime excess cancer risk end of the risk range, which indicated benzo (a) pyrene and dibenzo (a,h) anthracene were in need of priority control in the site. The risks for the whole research area were in the following order: south and southeast> west and north > east and northeast. The distributions of noncancer risks or cancer risks were similar with the distributions of pollutants concentrations.