Source Apportionment Of PAHs In Sediments From The Yellow River Estuary And Laizhou Bay

Polycyclic aromatic hydrocarbons (PAHs) were carcinogenic to humans, and a number of PAH compounds had been identified as either carcinogenic or mutagenic to both terrestrial and aquatic organisms. PAHs accumulated in different environmental media, such as air, waters and organisms, are introduced into the coastal environment by long distance transportation. The estuarine and coastal area, as a typical transitional zone between land and ocean, was a multifunctional and complex ecosystem with special ecological values and potential resources. Due to the interaction of land and ocean, the estuarine and coastal area was characterized by intense hydrodynamic conditions, frequent sediment transport and material exchange, steep physiochemical gradients and high biodiversity. In addition, the estuarine and coastal area was one of highly human activities zone which responds to global changes sensitively. This paper took the Yellow river estuarine and Laizhou Bay as a research object, and discussed the distribution of PAHs and sources apportionment. The method of isomer ratios was used for apportioning sediment PAHs sources qualitatively; chemical mass balance model and multivariate analysis were utilized and compared as quantitative methods, systemic developing technology for source apportionment of PAHs in coastal sediments. The main findings were as following: In the sediments of Yellow river estuarine, the total concentrations of sixteen PAHs varied from 47.40ng/g to 277.12ng/g (average concentrations were 101.6ng/g), with Naphthalin and Phenanthrene accounting for the most while Fluoranthene and Pyrene the next. The concentrations of 2,4-ring PAHs are quite high while PAHs with high molecular(5,6-ring) weight are low. The total concentrations of PAHs in the sediments varied from 23.03ng/g to327.53ng/g from Laizhou Bay (average concentrations were 138.04g/g). Total PAHs concentrations were at lower level in Yellow river estuarine and Laizhou Bay compared with relevant areas worldwide. The total content of organic matter of surface sediments in Yellow river estuarine sediment were within the range of 0.86-2.85%, and the surface sediment was mainly comprised of silt. While the total content of organic matter of surface sediments in Laizhou Bay sediment varied from 0.7% to 1.56%, with particle size distribution significantly different. Multiple linear regressions showed that the correlation of total content of PAHs and particle size distribution, organic matter is bad.According to ratio analysis (Phe/An, Fl/Fl+Py, IP/IP+BghiP, BaA/Chr, et al.), PAHs contaminations in Yellow River estuary and Laizhou Bay showed a mixed PAH input pattern,including oil pollution, coal burning, and wood combustion.According to the result of ratio analysis, six sources were established; including oil and asphalt refinery, coal combustion, wood combustion, gasoline engine exhaust, diesel engine exhaust and oil spill. Source profiles were collected from the literature. The results of chemical mass balance model indicate that coal combustion and wood combustion are the two major sources of PAHs in the Yellow river estuarine area, whose relative contribution were 30.5% and 27.7%; while gasoline engine exhaust accounted for 17.49%, diesel engine exhaust 12.53%, oil spill 8.04%, oil and asphalt refinery 3.73%. And Laizhou Bay's major sources of PAHs was coal combustion, which accounted for 34.16%; while gasoline engine exhaust accounted for 17.91%, diesel engine exhaust 13.1%, oil and asphalt refinery 18.15%, wood combustion 10.77%, and diesel-fuel leak 5.91%.The factor analysis- multiple regression analysis indicated PAHs contaminations in Yellow River Estuary area originated from coal and wood combustion, vehicles emission, oil spill, oil and asphalt refinery. The coal and wood combustion, vehicles emission, oil spill, oil and asphalt refinery respectively accounted for total PAHs 41.89%, 27.43%, 10.76%, 19.92%.PAHs contaminations in Laizhou Bay area originated from coal combustion, wood combustion, vehicles emission, oil spill. The coal combustion, vehicles emission, oil spill and wood combustion, oil and asphalt refinery respectively accounted for total PAHs 33.73%, 31.29%, 34.98%. The results of chemical mass balance model and factor analysis- multiple regression analysis were well consistent.