Three types of macromolecular organic matters (MOMs), i.e. humic acid (HA), kerogen+black carbon (KB), and black carbon (BC) were extracted from marine sediments of Xiamen Gulf, southeast of China. The chemical composition, morphological property and source of the three extractions were characterized by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS) and scanning electron microscope (SEM). The results showed that KB was the predominant fraction in MOMs, which accounted for 61.79%-89.15% of the total organic content (TOC), while HA consisted less than 5%. The relative high contents of kerogen and BC, and low contents of HA in the samples indicated that anthropogenic input might be the major source of organic matter in marine sediments near the industrial regions. The characterization of SEM, not only revealed morphological properties of the three fractions, but also allowed a better understanding of the source of MOMs. The δ 13 C values of the three fractions suggested that materials from terrestrial C 3 plants were predominant. Furthermore, the anthropogenic activities, such as the discharge of sewage, coal and biomass combustion from industry nearby and agricultural practices within drainage basin of the Jiulong River, were remarkably contributed to the variations in δ 13 C values of MOMs in the offshore marine sediments.
Atmospheric fine particles(PM_(2.5)) were collected in this study with middle volume samplers in Fuzhou,China,during both normal days and haze days in summer(September 2007) and winter(January 2008).The concentrations,distributions,and sources of polycyclic aromatic hydrocarbons(PAHs),organic carbon(OC),elemental carbon(EC),and water soluble inorganic ions(WSIIs) were determinated.The results showed that the concentrations of PM2.5,PAHs,OC,EC,and WSIIs were in the orders of haze > normal and winter > summer.The dominant PAHs of PM2.5 in Fuzhou were Fluo,Pyr,Chr,BbF,BkF,BaP,BghiP,and IcdP,which represented about 80.0%of the total PAHs during different sampling periods.The BaPeq concentrations of ∑PAHs were 0.78,0.99,1.22,and 2.43 ng/m3 in summer normal,summer haze,winter normal,and winter haze,respectively.Secondary pollutants(SO_4^(2-),NO_3^-,NH_4^+.and OC) were the major chemical compositions of PM2.5,accounting for 69.0%,55.1%,63.4%,and 64.9%of PM2.5 mass in summer normal,summer haze,winter normal,and winter haze,respectively.Correspondingly,secondary organic carbon(SOC) in Fuzhou accounted for 20.1%,48.6%,24.5%,and 50.5%of OC.The average values of nitrogen oxidation ratio(NOR) and sulfur oxidation ratio(SOR) were higher in haze days(0.08 and 0.27) than in normal days(0.05 and 0.22).Higher OC/EC ratios were also found in haze days(5.0) than in normal days(3.3).Correlation analysis demonstrated that visibility had positive correlations with wind speed,and negative correlations with relative humidity and major air pollutants.Overall,the enrichments of PM_(2.5),OC,EC,SO_4^(2-),and NO_3^- promoted haze formation.Furthermore,the diagnostic ratios of IcdP/(IcdP + BghiP),IcdP/BghiP,OC/EC,and NO_3^-/SO_4^(2-) indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou.
