PAH, PCB, TPH and mercury in surface sediments of the Delaware River Estuary and Delmarva Peninsula, USA

Surface sediment concentrations of polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB), total petroleum hydrocarbons (TPH) and mercury, were compared from two areas with contrasting land use history, the industrial Delaware Estuary and the rural Delmarva Peninsula (USA). TPH in the Delaware (38-616 mg/kg) and saturate/aromatic fractions suggested petroleum/industrial sources compared to biogenic sources in the Delmarva coastal control (< 34-159 mg/kg). Within the Delaware the ∑ PAH18 ranged from 3749 to 22,324 μg/kg with isomeric ratios indicative of petroleum combustion source/s, conversely, those in the Delmarva (5-2139 μg/kg) also yielded relatively higher perylene that were consistent with natural background levels derived from vegetation/coal combustion source/s. ∑ PCB(tri-hepta) concentrations in the Delmarva (0.6-6.5 μg/kg) were less than the threshold effect concentration (TEC), whereas the Delaware had received much higher PCB loading (18.1-136.8 μg/kg) as evidenced by a significantly higher amounts in some samples (> TEC).