Spatial Temporal Differences,Source Analysis And Migration And Diffusion Behavior For Polycyclic Aromatic Hydrocarbons Of Landscape Waters In Wuhu City

PAHs are a class of persistent organic pollutants with carcinogenic,teratogenic and mutagenic properties which are easy to be bioaccumulated,long-range transported,and difficult to degrade,posing a serious threat to environmental safety and human health.Nowadays,humans are concentrated in urban areas,and the landscape water is most closely related to human life.Therefore,it has great theoretical and practical significance to study the exposure concentration,temporal and spatial variation,influence factor,diffusion behavior and analyze the possible sources of PAHs in landscape water of city.The concentration of PAHs in the sedimentary phase,aqueous phase and suspended particle phase of lakes and rivers in Wuhu city was measured by gas chromatography-mass spectrometry?GC-MS?.The spatial distribution of PAHs in different functional areas of the main urban area and the correlation between organic carbon,black carbon and PAHs were analyzed by statistical analysis.The method of fugacity was used to investigate the effects of different concentrations of organic carbon and two forms of black carbon on the diffusion behavior of PAHs in sediment-water,suspended particles-water.The possible sources of PAHs in water three-phase media and their source contribution rates were compared and analyzed by using the characteristic ratio method and positive definite matrix factorization method..The main conclusions are as follows:?1?The winter pollution concentration of PAHs in the sedimentary facies of Wuhu City is 43.48-6388.40 ng/g,the average mass concentration is 1329.97 ng/g;the summer sedimentary facies PAHs exposure range is 15.98-4595.76 ng/g,and the average mass concentration is 735.33 ng/g;For monomeric PAH,the highest exposure concentration in winter is Fla while in summer is BbF;In terms of the composition characteristics of PAHs,the mid-high rings are the dominant ring in winter and summer;The concentration of PAHs in suspended particle phase in winter is 2.46-36.85 ng/L,and the average mass concentration is 11.27 ng/L while in summer the PAHs exposure range of suspended particle phase is 5.33-24.38 ng/L,and the average mass concentration is 12.78 ng/L.For monomeric PAH,the highest exposure concentration in winter and summer is Phe.As far as the characteristics of PAHs are concerned,the winter is mainly dominated by the low ring and the middle ring,and the summer is mainly dominated by the low ring.The water concentration of PAHs in winter is 0.19-52.23 ng/L,and the average mass concentration was 9.18 ng/L,the exposure range of summer is 6.95-43.20 ng/L,and the average mass concentration is20.26 ng/L.Nap is the highest exposure concentration of monomeric PAH in both winter and summer.In terms of PAHs composition characteristics,winter and summer are dominated by low rings.?2?The pollution status of PAHs in different functional areas is different,and the exposure degree of PAHs in different media of water is also different.The regular is as follows:old industrial area>commercial area>residential area>cultural and educational area.?3?In winter or summer,the distribution and pollution of PAHs in landscape water are significantly linearly correlated with TOC and BC.The correlation between PAHs and TOC in summer is greater than that with BC while the correlation between PAHs and BC_Cr in winter is more obvious than with TOC.The correlation between different forms of BC and PAHs is also different.In general,the correlation between BC_Crr and PAHs is more significant than BC_CTO and PAHs,indicating that charcoal plays an important role in the adsorption of PAHs.?4?The characteristic ratio method and PMF both indicate that PAHs in sediment mainly derived from coal and biomass combustion,and PAHs in suspended particle phase and water mainly come from petroleum combustion.?5?The migration and transformation rules of TOC and BC for PAHs between sedimentary facies and water phases were discussed by using fugacity method.The results show that with the increase of TOC and BC concentrations,PAHs tends to diffuse from water phases to sedimentary facies,indicating that the sedimentary facies is a sink of PAHs.Meanwhile,with the increase of the benzene ring number of PAHs,the high-ring PAHs tend to diffuse into sedimentary phase.The effect of BC_Cr in the migration and transformation for PAHs is better than BC_CTO.