Paper No. 5
Presentation Time: 10:00 AM
COMBINED APPLICATION OF δ13C AND MOLECULAR RATIOS IN SEDIMENT CORES FOR PAH SOURCE APPORTIONMENT IN THE NEW YORK/NEW JERSEY HARBOR
The New York/New Jersey (NY/NJ) harbor hosts variable amounts and sources of polycyclic aromatic hydrocarbons (PAHs). Analyses of radionuclides 137Cs and 7Be were used to assign approximate dates to individual sections of sediment cores collected from the Newark, Passaic, Raritan and Jamaica sub-basins of the Harbor. Two end-member PAH source components, petroleum-related PAHs (PRPAH) and combustion-related PAHs (CRPAH), were calculated by a carbon isotopic mass balance equation based on assumptions that petroleum-related d13CPy is -29, and that combustion-derived d13CPy is -24. Temporal trends of PRPAH in these cores are similar to those of the petroleum-derived unresolved complex mixture (UCM), whereas CRPAH resembled trends of Total PAH (TPAH). Three molecular ratios, fluoranthene to fluoranthene plus pyrene (Fl/(Fl+Py)), high molecular weight 4-6 ring PAH to total PAH (Ring456/TPAH) and parental to total (Par/(Par+Alkyl)), correlate strongly with each other, and shows a moderate to strong positive correlation with d13CPy. In contrast, the ratios of anthracene to phenanthrene plus anthracene (A/(Pa+A)), benzo[a]anthracene to benzo[a]anthracene plus chrysene (BaA/(BaA+Chy)), and indeno[1,2,3-cd]pyrene to indeno[1,2,3-cd]pyrene plus benzo[ghi]perylene (IP/(IP+Bghi)) show no, weak, or even negative correlation with the four well correlated ratios (d13CPy, Par/(Par+Alkyl), Fl/(Fl+Py), and Ring456/TPAH). Combined application of the four well correlated molecular indicators suggests that PAH contribution from combustion has become more important in most areas of the NY/NJ harbor in the last three decades.