Research On Concentration, Distribution And Composition Of Petroleum Hydrocarbons In Meizhou Bay Water

Meizhou Bay is a semi-closed natural harbor in Fujian province,which owns deepwater and broad harbor.It's not frozen and silting as well.In the recent years, with the foundation of wharf,the throughput of freight and the number of traffic sail increased fast.The extension of oil refinery and power plant lead to petroleum hydrocarbons(PHC) pollution in Meizhou Bay area.In the past,research on petroleum hydrocarbon in Meizhou Bay water column was focused on determine total petroleum hydrocarbons(PHC) in single investigation and experimental simulation. But to distributing character and composition of PHC in Meizhou Bay,it is short of full-scale research.Field research was done in this article from 2005 to 2008,in order to research horizontal distribution,Vertical profile and seasonal character in Meizhou Bay. Correlation analysis was done between PHC and environmental parameters.And n-alkane was chosen to be a biomarker.Sensitive and rapid analysis methods are build to investigate the pollution status in Meizhou Bay.The main results were as follows.(1) Comprehensive analysis horizontal distribution,Vertical profile,seasonal character and annual changes in Meizhou BayThe horizontal distribution in Meizhou Bay is PHC range 9.28～114.24μg/L,31.65μg/L in average.The horizontal distribution of PHC in Meizhou Bay is in high level inside and in low level outside.The max value was in the sea area nearby wharf and Xiuyu dockyard.PHC in Meizhou Bay is in high level in surface layer and in low lever in bottom,but it contrary to some individual stations.PHC in surface seawater of Meizhou Bay is high in spring,summer and autumn,low in winter.And it also increased year after year.(2) Relationships between PHC and environment factors of the water column in Meizhou BayThe content of DIN and DIP in the water column has the characteristic that the content inner bay was higher than outer bay.The water column was at eutrophication level in autumn and winter.PHC show a good positive relationship with DIN and DIP when PHC concentrations were low,with the correlation coefficient(r²) of 0.8382 and 0.6899,respectively.In addition,PHC displayed good positive relationships with Chl-a,COD,suspended material and turbidity,the correlation coefficient were 0.8154, 0.7032,0.7955 and 0.7311,respectively.(3) Composition and content of dissolved n-alkane and pollution status of PHC in Meizhou BayThirty-three compositions of n-alkane of the water column were quantitatively tested by chromatography separation and gas chromatography in Meizhou Bay.The total content of dissolved n-alkane was in the range of 1.22～1.55μg/L,and the average level was 1.35μg/L.The proportion of dissolved n-alkane in the PHC was slightly low.The maximum was found in Xiaocuo port and vicinity of oil refinery plant in the central section of Meizhou Bay,and show a trend of lowing gradually from inner bay to outer bay.Dissolved n-alkane presented bimodal distribution,and the carbon number was in n-C₈～n-C₃₆.The carbon number indicated aquatic organism and terrestrial biota were the common source of n-alkane.The carbon number also revealed serious PHC pollution in Xiaocuo port and vicinity of oil refinery plant.Carbon preference index (CPI),LMH/HMH and OEP were also close to 1.Pr/Ph and n-Alk/n-C₁₆ were in the range of 2.93～3.12 and 17.57～21.47,respectively.The content of phytane was from 8.9 to 10.1 ng/L.All in all,the seawater of Meizhou Bay was in little pollution of PHC.