The transport and fate of particulate hydrocarbons in an urban fjord-like estuary

Abstract

Hydrocarbon concentrations were measured on suspended particulates and on surficial marine sediments in the urban fjord-like estuary of Puget Sound, Washington. These data were combined with sediment deposition rates, suspended particulate concentrations and circulation data to assess hydrocarbon distributions and fates. Evaluation of major sinks for petroleum hydrocarbons (UCM) and polycyclic aromatic hydrocarbons (PAH) in an urban estuary indicates that > 90% of the hydrocarbons which are associated with suspended particulates in the main basin of Puget Sound are deposited in the estuarine sediments. Approximately 63% of the PAH and 100% of the UCM associated with particles in the main basin settle directly to the sediments. The remainder is carried to the main basin sediments via horizontal transport from other areas. Trends in PAH ratios are used to identify major sources of PAH. Estimated sources of PAH are balanced by the estimated sinks.