Distribution, Accumulation And Source Identification Of Polycyclic Aromatic Hydrocarbons In The Surface And Core Sediments Of The Yangtze Estuary

Polycyclic Aromatic Hydrocarbons (PAHs) are a kind of typical persistent organic pollutants, extremely low levels in the environment, but have the obvious toxic (carcinogenic and degraded wangshifu). Due to the special physical and chemical properties, the PAHs in environment are difficult to resolve, and through the food chain to be bio-accumulated get bioaccumulation and biomagnifications, and threat the Biological communities and population in estuarine environments, and even the human health, eventually produced a serious potential decay and degradation of threat to the ecosystem environment.Thus, a long time, PAHs are preferred to monitor and control pollutants in the estuarine environment. As one of the three estuary in China, Yangtze estuary which has peculiar estuary process and the special geographical position in international estuarine and coastal areas has the important position. This research in Yangtze estuary area for the monitoring and management of PAHs provides scientific basis, has a practical instruction meaning,and enrich the content of Yangtze estuary PAHs biogeochemical cycles research.The concentrations of PAHs in surface sediments of Yangtze estuary area were in the range of 348.7～961.6ng/g (average value:606.7 ng/g). The 3～4 ring of PAHs are the dominated monomers in sediments of researching area. The LMV/HMV ratio (both larger than 1 in Yangtze estuary) indicated that PAHs are from the low to medium temperature fuel burning and petrogenic source. Source apportionment by principal component analysis reflected PAHs derived from incompleted combustion and petroleum.In recent years, figures show that the PAHs in Yangtze estuary have a downward trend, indicate that the PAHs have improving trend. Burning source especially coal, oil, lumber of incomplete combustion has become the main source of PAHs.The energy structure in Shanghai makes the 3 rings and 4 rings component-based PAHs in sediment. During the core Sediments of Chongming,the PAHs in surface sediments is not the highest,the highest values often occurs in the subsurface,it appears 2-3 peaks with the depth, and then the content stable after the peak. It instructions that the PAHs in surface sediments might be a certain degree of decomposition and volatilization;The PAHs in dry season are higher than in flood sreson,it may be due to photodegradation,the absorption of plants and animals,and the river's run-off; Source apportionment by principal component analysis reflected the PAHs at East Chongming tidal flat derived from incompleted the coal, gasoline and coke combustion.In the study area,salinity and particle size had less impact on the PAHs,and almost no correlation between the PAHs. There was a good correlation between the total organic carbon and PAHs in surface sediments of the Yangtze Estuary However, sediment core samples in the East Chongming tidal flat had no obvious correlation. Whether in the Yangtze estuarine and coastal sediments or the core sediments in the East Chongming tidal flat, there was nocorrelation between the black orcarbon and the PAHs.The comparison with similar literatures showed that the contamination of PAHs in Yangtze River estuary and coastal area is much lower than foreign severely polluted estuaries and higher than most reported data of China.Only the Fluorene was higher than ER-L and ISQV-L in surface sediments of the Yangtze Estuary.But the BbF and BkF were detected, instructioned that in this area still had a potentially harm Compared to other estuary core sediments,the PAHs in the East Chongming tidal flat wre lighter, in the medium level.