The Spatial And Temporal Distribution, Source And Bioavailability Of PAHs In Qiantang River

Surface water is polluted more seriously by organic contaminants.The protection of surface water resources is an important task for us.It is necessary to investigate the concentration,source and bioavailability of contaminants for the safety of drinking water.This dissertation selected Qiantang River as representative drinking water resource.The concentration,spatial and temporal distribution,and source of polycyclic aromatic hydrocarbons(PAHs)were characterized.Then,the input and output of PAHs in estuary section of Qiantang River were estimated. Furthermore,the bioavailability of PAHs in sediment were researched.The results provided valuable information for protection of drinking water resource.The main conclusions of this work were as follows:(1)The total concentrations of 15 PAHs in water,sediment and soil from Qiantang River were ranged from 70.3 to 1844 ng/L,from 91.3 to 1835 ng/g dw and from 85.2 to 676.2 ng/g dw with the mean values of 288.2 ng/L,326.6 ng/g dw and 350.2 ng/g dw,respectively.The total concentrations of PAHs were increasing in recent years.The concentrations of PAHs were highest in winter and lowest in summer.The total concentrations of PAHs in city zones were higher than those in rural areas.Ratios of AN/(AN+Phen)and Flur/(Flur+Py)calculated suggested that PAHs in Qiantang River were mainly from petrogenic origin and the contribution of petrogenic PAHs was decreasing during the last two years.(2)The input and output of PAHs in estuary section of Qiantang River were 21.83 t/yr and 13.49 t/yr,respectively.The input of PAHs was higher than output of PAHs,which caused the increase of concentrations of PAHs in Qiantang River.(3)XAD-2 assisted desorption assay can be used to assess the bioavailability of PAHs in the sediment.Positive linear relationship was found between the non-bioavailable fraction of PAHs and TOC content when the samples were from the same origin.