FY 1984

Vertical transport and sedimentation of hydrocarbons in the central main basin of Puget Sound, Washington

Bates, T.S., S.E. Hamilton, and J.D. Cline

Environ. Sci. Technol., 18(5), 299–305, doi: 10.1021/es00123a003 (1984)

Concentrations and vertical fluxes of total carbon, aliphatic hydrocarbons, and polycyclic aromatic hydrocarbons (PAH) were determined in suspended matter and the underlying sediments in the central main basin of Puget Sound, Washington. Suspended matter was collected seasonally at our depths in the water column using sequential sampling sediment traps. The flux of PAH through the 50- and 100-m horizons accounted for 84% of the PAH accumulating in the underlying surface sediments. The concentration of PAH in the suspended matter from these traps, however, was 3 times greater than the concentration of PAH in the surficial bottom sediments. Laterally transported suspended matter in the bottom boundary layer is apparently diluting the PAH during sedimentation. The flux of aliphatic hydrocarbons to the sediments was greater than the accumulation rate in the sediments, indicating an alteration of these hydrocarbons within the water column or differential particle transport. The vertical distributions of hydrocarbons in the bottom sediments showed concentration increases paralleling the urbanization of the Puget Sound basin.