ABSTRACT
This chapter discusses processes that influence metal concentrations in sediment and evaluates the approaches most effective in separation of anthropogenic contamination from natural influences. The discussion is limited to estuarine and coastal marine bed sediments and emphasizes behavior that is common to the heavy metals Ag, Cd, Cu, Ni, Pb, Zn, Hg, and Cr. Metal concentrations in marine and estuarine sediments are determined by metal inputs and are affected by reactions at particle surfaces that influence the quantity of metal adsorbed, reduction/oxidation reactions, and differences in solution chemistry that affect particle formation and adsorption or desorption of metals. The concentrations of the most important metal-reactive components of sediments may vary widely among estuarine and marine environments. Normalizing metal concentrations to a textural or compositional characteristic may improve the sensitivity of comparisons of metal concentrations in sediments. Surveillance or monitoring studies also must consider temporal variability, spatial heterogeneity, and redistribution of contamination by physical transport in their design.
