| In recent years,the economic construction of various regions in China has gradually entered the process of integration,and rapid urbanization and regional integration have become a trend.Under national policy and guidance,the process of urban construction and regional integration in Shenfu New District has gradually accelerated.In the process of urban construction,the discharge and accumulation of various pollutants pose challenges to the local environmental and also threaten the health of residents.Polycyclic aromatic hydrocarbons?PAHs?are a typical type of persistent organic pollutants,which are widely present in various environmental media such as the atmosphere,soil and water.Its refractory,carcinogenic,teratogenic and mutagenic properties bring great harm to the ecological environment and human health.In this study,the groundwater and soil profiles of Shenfu New District during the wet and dry seasons were taken as the research objects,and the residues,composition characteristics and spatial distribution of PAHs in the groundwater in the study area were analyzed.Explore the influence of seasons,land types,and urbanization factors on the distribution of PAHs in groundwater;and by analyzing the distribution and composition of PAHs in the soil profile,the effects of soil physical and chemical properties and PAHs physicochemical characteristics on the migration in the soil were revealed.The isomer ratio method,PCA-MLR and PMF were used to analyze the source of PAHs in groundwater and soil profiles,and the ecological risk and health risk of PAHs in groundwater were evaluated.The main conclusions are as follows:1.The concentration of groundwater PAHs in the study area were:dry season:8.54?2195.53ng/L?average 466.98ng/L?,wet season:13.38?963.98ng/L?average 139.56ng/L?,the 2?4 rings PAHs in the groundwater in the two seasons showed higher concentration.PAHs showed a point-like distribution in the dry season,and showed a planar distribution in the wet season.The content of PAHs in soil profiles under different land types are:city 1?549.13?13355.77?g/kg?,upland field?40.51?7752.55?g/kg?,paddy field?372.75?2220.41?g/kg?,city 2?37.40?1139.94?g/kg?,forest?5.69?401.45?g/kg?,3?4 rings PAHs account for the main proportion in the soil profile.Soil organic matter content significantly affect the distribution of PAHs,and the solubility,vapor pressure,and soil-water partition coefficient of PAHs significantly affect its migration behavior in the soil profile.PAHs in the soil profile would migrate to shallow groundwater,which is related to the concentration and ring number distribution of PAHs in groundwater.2.The results of PAHs source analysis indicate that the main source of PAHs in groundwater is the combustion source.The PMF model results are more meaningful than PCA-MLR.The main sources of PAHs during dry season are coal combustion sources?47.1%?and coal,gasoline and diesel combustion sources?30%?;the main sources of PAHs during wet season are coal combustion sources?37.8%?and oil spills,coal/biomass combustion mixture source?35.6%?.The source of PAHs in the soil profile layer is also dominated by combustion sources.The main sources of PAHs in city 1,city 2,paddy fields,dry fields,and forest are biomass,fossil fuel combustion sources?95.1%?,combustion sources?77.9%?,oil leakage sources?55.3%?,combustion sources?93.8%?,and oil leakage and biomass combustion sources?53.9%?,respectively.The source analysis results show that the proportion of combustion sources in the urbanized area soil profile layer is higher than that in the groundwater.3.The evaluation results of the Nemerow index,toxicity equivalency quantity and risk quotient show that the ecological risk of groundwater in dry season is higher than that in wet season.The results of the non-carcinogenic risk assessment of the RAGS model show that the non-carcinogenic risk index HI values of 16 PAHs are far less than1,and the non-carcinogenic risk of PAHs is at a low level;the results carcinogenic risk assessment of RAGS model showed that the carcinogenic risk index TCR of 16 PAHs through are less than 1×10-4,and the non-carcinogenic risk at an acceptable risk level.The results of ILCR show that in some sampling points of dry season,the carcinogenic risk assessment results for children,adolescents and adults range from 10-6to 10-4,indicating potential health carcinogenic risk.The carcinogenicity index of people of different ages shows the rule of adults>children>adolescents.Overall,the carcinogenic risk in this area is at a low level. |
PDF Full Text Request