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.