Porewater Gradients and Diffusive Benthic Fluxes of Co, Ni, Cu, Zn, and Cd in San Francisco Bay

摘要

In order to determine the remobilization of Co, Ni, Cu, Zn, and Cd from the sediments, gradients of their dissolved (<0.45 μm) and particulate concentrations were measured in both relatively pris- tine and contaminated sediments of San Francisco Bay, as well as relatively pristine adjacent embayments (Tomales Bay and Drakes Estero). Three mechanisms were determined to regulate the diage- Netic release of those elements to porewaters: (I) the degradation Of organic matter in oxic and suboxic zones; (ii) the reduction of Mn In suboxic zone; and (iii) the formation of soluble metal-sulfide Complexes in anoxic zones.