Streamlining contaminated sediment management: the use of advanced sediment characterization — preliminary results

Abstract

Simply knowing the geographic extent of sediment contamination within a bay or estuary does not provide sufficient insight to help a site manager or stakeholder begin to assess how to manage sediments deemed either an ecological risk or regulatory violation. A better approach is to assess contaminant distribution and behavior at a micro-scale in parallel with macro-scale site assessments. In such an approach, a site investigation includes an assessment of contaminant/sediment biogeochemistry, as it will impact bioavailability, risk, and potential management options. This paper reviews some approaches for assessing contaminant bioavailability, distribution and degradability, and presents preliminary results from some biogeochemical sediment assays. Some of the potential uses and limitations of such assays are discussed. Selective leaches, using alcohol or digestive juices to determine bioavailable contaminant fractions still require some validation. Assessments of contaminant distribution as a function of grain size can lend insight into both contaminant mobility and management strategies. Biodegradation studies in real sediments are complicated by analytical and heterogeneity difficulties, but can, if carried out carefully, provide useful information.