Source Apportionment Of PAHs In Coastal Surface Sediments From Jiaozhou Bay And Rizhao Offshore Area

32 surface sediment samples were collected from Rizhao offshore area and Jiaozhou Bay in February 2007 and September 2008, respectively. The concentrations of 16 Polycyclic aromatic hydrocarbons ( PAHs ) were analyzed by gas chromatography- flame ionization detector(GC-FID) and gas chromatography-mass spectrometry(GC-MS). The chemical mass balance (CMB) model and factor analysis (FA)with multiple linear regression (MLR) model were used to quantitatively apportion sources of PAHs in surface sediments.The total PAHs concentrations in surface sediments from Jiaozhou Bay ranged from 1242.21 to 29558.13 ng/g, and average concentrations were 5065.09 ng/g. PAHs concentrations in surface sediments were at relatively moderate levels in comparison with those reported for other marine systems around the word. The PAHs composition distribution in this area was mostly dominated by high molecular weight PAHs(4~6 rings). There was a correlation between PAHs concentration and organic carbon content. But no correlations were found in particle size distribution, pH and PAHs concentrations. The total PAHs concentration from Rizhao offshore area ranged from 76.38 to 27512.02 ng/g, with an average concentration of 2622.58 ng/g. The PAHs composition distribution in the area was mostly dominated by low molecular weight PAHs (2~3 rings). The PAHs concentrations in the sediments were not correlated to the particle size distribution, pH and organic carbon content.The isomeric ratios such as PhA/AN,FlA/Py,BaA/Chy and IP/(IP +BghiP)were used to identify possible sources of PAHs in coastal surface sediments from Jiaozhou Bay and Rizhao offshore area. The results indicated that the major sources of PAHs in surface sediments from Jiaozhou Bay were contributed by coal combustion, gasoline and diesel engines exhaust. The possible sources of PAH in sediments from Rizhao offshore area were gasoline and diesel engines exhaust, coal and wood combustion, coke oven and diesel oil leaks.According to discharging features of Qingdao City, three kinds of PAHs sources identified were waste water, coal power plant and coke oven. Based on the analysis of PAHs from three source samples and citation from the literatures, the PAHs source profiles of various sources were created. Because of chemical, photochemical, and biological degradation of PAHs, the degradation factors of selected PAHs were caculated based on the first-order reaction rate constants and optimum reaction time. After including degradation factors, the modified CMB model results indicated that waste water and coal power plant were the two major sources of PAHs in surface sediments Jiaozhou Bay. The source contributions estimated by the CMB8.2 model were 69.68% and 30.32%. In Rizhao offshore area, coal power plant was the major PAH source and diesel oil leaks, diesel engine exhaust, and coal residential were three minor PAH sources. Their contributions were 9.25%, 15.05%, 13.15%, and 62.55%, respectively.FA/MR model were also applied to source apportionment of PAHs to test the result of CMB model. In Jiaozhou Bay, the results showed that the combined contribution of waste water and coal combustion was 67.02%. The combined contribution of coke oven and oil leaks was 32.98%. There were some differences between the results of CMB model and FA/MR model.In Rizhao offshore area, the combined contribution of coal, wood combustion and coke oven was 74.12%. The contributions of diesel, gasoline engines exhaust and diesel oil leaks were 24.52%, 1.36%, respectively. The results were similar with that of CMB model.Comparing the results between two models, the conclusion was that the energy consumption structures of Jiaozhou Bay and Rizhao offshore area were similar. The PAHs in coastal surface sediments from Jiaozhou Bay and Rizhao offshore area were largely influenced by coal combustion.