Sources and Distribution of Aliphatic and Polyaromatic Hydrocarbon in Surface Sediments of Gyeonggi Bay

Abstract

Total organic carbon (TOC), total nitrogen (TN) contents and their δ 13C and δ 15N values were determined for Gyeonggi and Taean Bay as well as aliphatic and polyaromatic hydrocarbon were determined from surface sediments samples in Gyeonggi Bay. Higher TOC and TN concentrations were shown at the mouth of the bay and decreased inward.TOC content showed a positive correlation with mean grain size of surface sediments of Gyeonggi Bay sediments. C/N ratios ranged from 4 to 16 for Taean Bay, decreasing towards the inner bay. δ 13C values of organic matter increases from -31‰ to -19‰ and from and -24.76‰ to -5.96‰ respectively away from the coast indicating a decrease of terrestrial input. δ 15N values were in the range of -0.26‰ to 9.8‰ and 3.65% to 9.51‰ showing a mixture of both marine and terrestrial sources near the coast and predominant marine sources away from the coast for both sites. Lower molecular weight/higher molecular weight (LMH/HMW), carbon preference indices (CPI) showed that the sources of aliphatic hydrocarbon were mainly marine biogenic in origin and followed by vascular plant and petrogenic. Phenenanthrene/anthracene and fluoranthene/pyrene indices showed that the source of polyaromatic hydrocarbon is majorly petroleum combustion. Low correlation between aliphatic and polyaromatic hydrocarbons indicates different sources between both hydrocarbons. Principal component analysis revealed that the source for n-alkanes are attributed to marine biogenic source, terrestrial or land derived and petrogenic source while polyaromatic hydrocarbon from petroleum combustion source.