Acid Volatile Sulfides and Simultaneously Extracted Copper, Lead, and Zinc in Sediments of Sinclair Inlet, Washington
2006
Johnston, Robert K.
Acid volatile sulfides (AVS) and simultaneously extracted metal (SEM) concentrations of copper (Cu), lead (Pb), and zinc (Zn) were measured in the marine sediments of Sinclair Inlet, Puget Sound, Washington, as part of a project to evaluate the flux of metals between the sediment and bottom water of the Inlet. The AVS samples were collected from the same stations used to measure metal fluxes with a benthic chamber. The stations represented a range of previously measured heavy metal sediment concentrations in the Inlet. Two sediment cores (10 to 30 cm depth) were collected from each station; one core was selected to determine the AVS profile (2-cm increments), and the other was homogenized to obtain a composite AVS value for the top 10 cm. The AVS measured in composite samples ranged from 0.8 to 98.0 micrometers mol/g. For nine of the ten stations composite AVS concentrations were 2.2 to 10.3 times higher than the SEM concentrations of Cu, Pb, and Zn, and 1.1 to 6.2 times higher than the sum of divalent metal concentrations (Cd, Cu, Hg, Ni, Pb, Ag, and Zn) measured in bulk sediment grabs collected from the same stations. One station has a composite AVS concentration lower than the composite SEM concentration, resulting in SEM/AVS = 2.5. Seven of the ten stations has high AVS concentrations at the surface (> 20 micrometers mol/g), which increased at intermediate depths and decreased towards the bottom of the core. Simultaneously extracted Cu profiles were relatively uniform with depth and ranged from 0.1 to 11.2 micrometers mol/g. There was not a clear relationship between AVS and metal flux measured with the benthic chamber.
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