Assessing and managing contaminated sediments: Part I, developing an effective investigation and risk evaluation strategy

Abstract

This is the fi rst of a two-part review of the current state-of-the-science pertaining to the assessment and management of contaminated sediments. The goal of this review is to introduce some of the major technical and policy issues stemming from the assessment and management of contaminated sediments, highlight a number of aspects of contaminated sediment assessment and management found to be successful, and, when appropriate, address the barriers that still exist for improving contaminated sediment management. In this paper, Part I, the many key elements of an effective investigation and risk evaluation strategy are reviewed, beginning with the development of a conceptual site model (CSM) and including a discussion of some of the key factors infl uencing the design of sediment investigations and ecological risk assessment of sediment-bound chemicals on aquatic biota. In Part II of this paper (Apitz et al. 2005), various approaches are reviewed for evaluating sediment risk and monitoring sediment remedy effectiveness. While many of the technical and policy issues described in this review are relevant to dredged material management, the focus of this paper is on sediment assessment for environmental management.

Use of Data on Contaminant/Sediment Interactions to Streamline Sediment Assessment and Management

“…These actions range from no action (either because risks do not exist or are not controllable) or institutional controls to more aggressive containments, treatments, or removal actions. Another important term used is Conceptual Site Model (CSM, e.g., American Society for Testing and Materials [ASTM], 1995;2005a). CSM can be defined as a three-dimensional description (either qualitative or quantitative or a mixture of both) of a site and its environment, which defines what is known (or suspected) about the contaminant source area(s) and physical, chemical, and biological processes that affect contaminant transport from the source(s) through environmental media to potential environmental receptors.…”

“…While ambient or background levels of contaminants can be bioavailable, and may cause ecological impact, they are almost impossible to manage on a site-specific basiscost and logistics make it improbable that an entire region will be remediated, and if specific sites are remediated to below ambient levels, those sediments will probably be subject to recontamination by background sediments. Thus, it is important at a given site to examine contaminant distribution relative to regional, ambient, or background levels, and to select reference sites with care 2005a and. This report discusses how data on sediment/contaminant geochemical signatures and interactions can be used to address these issues (see Section 2.6 for a more detailed discussion).…”

Geochemical Distribution, Enrichment, and Potential Toxicity of Trace Metals in the Surface Sediments of Okinawa Mangrove, Southwest Japan

“…Sediments are the ultimate sink for anthropogenic chemical contaminants that may be contained in effluents originating from industrial, urban, recreational, and agricultural activities (Hatji et al, 2002;Apitz et al, 2005). The geochemical analysis of sediments thus provides an insight into the pollution status of the environment with respect to diverse chemical elements such as trace metals.…”

A chemometric approach to the environmental problem of predicting toxicity in contaminated sediments

“…However, sediments can act as sinks of multiple chemicals that accumulate over time and could represent a potentially significant hazard to the ecosystem and human health [2]. The assessment of sediment quality is not an easy task, though, so it should be carried out through tiered decision-making frameworks in sequential steps of increasing complexity and cost [3].…”