| Maritime oil spill accidents have now represented a global environmental problem and received great attention around the world. Polycyclic Aromatic Hydrocarbons (PAHs) is a kind of typical oil pollutant with high toxicity, semi-volatility and bio-magnification which has an adverse effects on humans and other animals, so the studies about the fate of PAHs were very important. In order to provide extensive information of residue, pollution, distribution and sources of 46 PHAs compounds after oil spill, water and sediment samples were collected in coastal environment of Dalian. The fingerprinting of different types of PAHs was established in order to distingusish different source of PAHs in water. Multi-medium fugacity model which can simulate organic pollutants'fate in the different mediums and quota attribute the special and temporal changing regulations of fugacity, concentration and quality in the environment multi-mediums. All the investigation would gain pollution status of PAHs after oil spill, apply as the scientific for pollutant control and management, and have great significance for protecting people's health and safety.In the first part of this thesis, source profiles of PAHs in water was established. The research shows that the source profiles of PAHs in crude oil, sediment-water exchange, atmospheric deposition, surface runoff, wastewater and secondary release from sediment were significantly different. In crude oil, alkyl-PAHs were predominant, among which methylphenanthrene were dominant PAH congeners. The concentrations of PAHs in gaseous phase were an order of magnitude higher than that in particle phase. Observed from composition, light weight PAHs were the most abundant compounds in the gaseous phase, while heavy weight PAHs were predominant in the particle phase. Naphthalene, phenatherene and methylphenanthrene were the most abundant PAHs in runoff water. Naphthalene,1-methylnaphthalene and 2-methylnaphthalene were the most abundant PAH congeners in domestic sewage effluents. Heavy weight composition of PAHs were the most abundant compounds in sediment.In the second part of this thesis, pollution characteristics of PAHs in oil apill area after oil spill were studied. The research shows that the concentration of ?46PAHs ranged 260-1620 ng/L with a mean value of 654±430 ng/L in sea water and the concentration of ?46PAHs ranged 91-2030 ng/g dw with a mean value of 550±342 ng/g dw in sediment of oil spill area after oil apill. A significant relationship was found between the concentration of ? 21PPAHs and ? 25APAHs both in seawater and sediment, showing the similar sources, degradation and transport pathway in pareant PHAs and alkyl PAHs. A significant relationship was found between the concentration of PAHs in seawater and the distance from the oil spill site, indicating the concentration of these compounds in seawater along coastal area was obvious affected by oil spill. A significant relationship was found between the concentration of PAHs in sediment at each site and the distance from industrial area, suggesting that industrial area received more historical input from local source. Observed from composition, light weight PAHs were the most abundant compounds in water and light heavy weight PAHs were in sediment. Sources of PAHs were investigated using principle component analysis and contributions were further estimated by multiple linear regression. The main sources of PAHs for seawater were crude oil sources and then were urban runoff, effluents sources, water-sediment exchange, water-air exchange and atmospheric particle deposition. For sediment, the main source were pyrogenic, then were petrogenic and diesel fuel source.In the third part of this thesis, pollution characteristics of PAHs in coastal environment of Dalian after oil spill were estimated. The results showed that concentration of ?46PAHs (in ng/L) was 136-621 with mean of 357 before oil spill and 65.0-1230 with mean of 297 after oil spill in seawater. For sediment, the concentration of ?46PAHs (in ng/g dw) was 63.55-635.77 with mean of 213.75 before oil spill and 71.08-1086.59 with mean of 195.70 after oil spill. Besides oil spill area, the temporal trends of PAHs in both water and sediment showed winter were significantly higher than summer (P<0.05). The spatial trends of PAHs showed Bohai area were significantly higher than Huanghai area (P<0.05). PAHs concentrations were significantly higher in industrial area than urban area (P<0.05) and rural area (P<0.01). The results of sources of PAHs analysis showed that the main source of PAHs in water were water-air exchange and atmospheric particle deposition before oill spill and crude oil sources after oil spill. The main sources of PAHs for sediment were fossil and biomass burning and diesel fuel before oil spill while crude oil, fossil and biomass burning and diesel fuel source after oill spill. Analysis of water-sediment exchange of PAHs showed that PAHs released from sediment to seawater was the major process for PAHs before oil spill, while different trends after oil spill. Risk assessment showed seriously ecological risks of PAHs in water and slight potential health risks in sediment.In the fourth part of this thesis, transfer and fate of PAHs in multi-medium of Dalian area were discussed. A level? fugacity model was applied to calculate the multi-interface transfer flux and concentration distribution of PAHs. The main output of PAHs in water were interphase advection, and then interphase mass transfer with sedimentation and adsorption. As for air, the main output of PAHs were interphase reaction, and then atmospheric particle deposition and interphase advection. Soil and sediment as important sink of PAHs pollutants in environment which residue accounts for over half of the total. The reliability of the model was verified by the coincidence of the calculated and the measured concentration in the same period. It's an effectivet tool to study their concentration levels, and transfer processes between adjacent compartments quantitatively, and the results of simulation are significant to environmental pollution prediction, ecological risk assessment and optimization of environmenltal pollution control measures. |
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