| Beijing-Hangzhou Grand Canal (Subei Section )is the east route of Water Transfer Project from South to North in China, which water quality will significantly affect the efficiency of Water Transfer Project from South to North. With the water transferred, the chemical balance in the water of The Grand Canal will change, and a series of chemical processes will happen. With the aid of Jiangsu nature science fund, we collected 96 samples of Beijing-Hangzhou Grand Canal (Subei Section ),and 58 samples of three storage lakes.We focused on the distribution,source apportiment and assessment of PAHs in surface sediments and water of Beijing-Hangzhou Grand Canal (Subei Section ), we also researched the release kinetics of PAHs in the sediments of Beijing-Hangzhou Grand Canal (Subei Section ).The main conclusions of this work were as follows:(1) The average total concentrations of 16 PAHs in sediment and water from Beijing-Hangzhou Grand Canal (Subei Section ) were 5239ng/g and 5930 ng/L , which were in moderate level compared with other waters. TOC was important for PAHs distribution in sediments. The concentrations of PAHs in different section arranged from high to low: Xuzhou section>Huaian-Suqian section>Yangzhou section,Weishan lake>Hongze lake>Luoma lake. The PAHs concentrations of water were higher in flood seasons than that in dry seasons,the PAHs in the watercourse Beijing-Hangzhou Grand Canal (Subei Section ) will significantly affect the efficiency of Water Transfer Project from South to North.(2) Ratios of Phen/Ant,Fla/Pyr , Sources apportionment by principal component analysis reflected that PAHs in Beijing-Hangzhou Grand Canal (Subei Section) were mainly from coal ,coke,firewood and petroleum and diesel oil combustion. The main sources of PAHs in Hongze lake, Luoma lake and Weishan lake were mainly from coal,firewood and petroleum and diesel oil.(4)The ecological risk of surface sediment and water in Beijing-Hangzhou Grand Canal (Subei Section) was assessed with the methods of sediment quality guidelines (SQGs) and HQ, respectively. The results showed that the concentration levels of PAHs in the study area have not caused the marked negative influence on organism. However DahA compound in Huaian-Suqian section sediment and Ace, Phe, Ant and DahA compounds in Xuzhou section sediment were present in excess of the moderate ERM, BaP in water were present in excess of the Ecological criteria of PAHs in water, and the biological effects exist.(5) TOC was important for PAHs distribution in sediments. Additionally, sediment organic matter type and structure also played an important role in PAHs distribution in different grain size fractions. Release kinetics of PAHs in the sediments were studied by experiments. The release rules were studied under static and suspended water conditions. The results showed that there were faster release speeds at the beginning of the experiment,and the release speeds slow down gradually with the increasing time. The factors that influence the release of PAHs from the sediment arranged from high to low: The concentration of TOC in the sediment, suspended condition, the temperature and pH.The PAHs concentrations in the water could effectively reduced after 5 times water-exchange, but at last the PAHs concentrations in the overlying water will keep stable levels because of the release from the sediments. A release kinetic model of PAHs from aquatic sediments was set up on the basis of these data. Cw= [1-Fe-K1t-(1-F)e-K2t]×B. The test result showed that the simulation data by the kinetic model can well fit the measure data, so the model can be used to describe the release kinetic proeess of PAHs from the sediments to water.
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