Research On Monitoring Of Contamination And Potential Health Risk Of PAHs In Soils Surrounding Industrial And Traffic Areas

Polycyclic aromatic hydrocarbons(PAHs)are a class of organic pollutants that are widespread in multiple environmental medias,mainly originated from the incomplete combustion and high temperature pyrolysis of coal,petroleum,and other carbonaceous materials.As a group of environmental contaminants with mutagenesis,carcinogenesis and teratogenesis,PAHs accumulation in urban soil has received widespread attention from researchers around the world in recent years.Soils in various functional areas of the city tend to identity different characteristics.Generally,the concentrations of PAHs are higher in soils of industrial and traffic areas,and lower in soils of suburban or rural areas.However,relatively minor attention has been paid to the distributions of PAHs in soils surrounding industrial and traffic areas in cities.Hence,this research reports a comprehensive investigation focusing on monitoring the concentration,composition profiles,distribution,source identification,and risk assessment method of PAHs from soils surrounding an industrial area and a traffic area.Moreover,an ecological demonstration village is also selected to increase comparability.Our findings are as follows:(1)The levels of ∑16PAHs ranged from 150.2 to 83096 ng·g-1 with an average concentration of 7680.4 ng·g-1 in soils surrounding industrial area,337.4 to 27967.5 ng·g-1 with an average concentration of 5234.2 ng·g-1 in soils surrounding traffic area,and 49.4 to 778.2 ng·g-1 with an average concentration of 213.5 ng·g-1 from surrounding soils in an ecological demonstration village.Although high molecular weight PAHs were common dominant contaminants in all study areas,the composition profiles of 16 priority PAHs in soils from the sampling sites had large variances due to the variations in land use patterns from sampling areas.PAHs in soils around the industrial zone have seriously exceeded the pollution standard at several sampling sites,and soil PAHs contamination around industrial area is the most serious.PAHs contamination in soils around the traffic area is relatively serious.Soil PAHs accumulation in the vicinity of the ecological demonstration village is comparatively lighter,and the overall pollution level is at an acceptable level.(2)The study identifies the sources of soil PAHs surrounding industrial area,traffic area,and an ecological demonstration village.The sources were analyzed qualitatively,semi-quantitatively and quantitatively by isomer ratio,cluster analysis and principal component analysis,respectively.The conclusions are as follows:the overall level of soil PAHs is higher in the vicinity of industrial area,and the main sources are combustion sources such as petroleum,coal combustion and biomass combustion.The main sources of soil PAHs in the vicinity of traffic area are traffic exhaust emissions and combustion of coal,fossil fuels and biomass.The main sources of soil PAHs around the ecological demonstration village are coal and biomass combustion.(3)The health risk and ecological risk of soil PAHs accumulation were evaluated by Incremental Lifetime Cancer Risk Model(ILCR)and Nemerow Integrated Pollution Index(NIPI),respectively.ILCR model results revealed that the health risk of PAHs accumulation in surrounding soils from industrial area reached level Ⅳ(potential high risk),which could have a serious negative impact on the exposed population.The health risk of PAHs accumulation in the soil around traffic area was at warning level Ⅱ(potential low risk).Soils around the ecological demonstration village is at warning level Ⅰ(little to no risk).Dermal contact is the most crucial exposure routes.Meanwhile,among two age groups of exposure subjects exposed to soil PAHs,adults may face a higher potential health risk than children,and female health risk being slightly higher than male.Moreover,ecological risk of PAHs in surrounding soils was generally at a safe level from industrial and traffic areas except for some sampling sites,and the ecological risk of PAHs in soils in the vicinity of the ecological demonstration village was all at a safe level.