Beneficial Use of ‘Contaminated' Dredged Material: Assessing the Risk.

Dredged sediments generally contain low concentration of contaminants associated with residential, agricultural, municipal, or industrial activities in the watershed.  The risk associated with using contaminated sediments for beneficial purposes is determined by the bioavailability of contaminants and exposure ecological and human receptors.  The potential for contaminants to migrate in the environment through various pathways (surface and groundwater, volatile and particulate emissions, plant and animal bioaccumulation) must consider various factors, such as organic carbon, pH, clay content, etc., that control the fate and transport of contaminants and ultimately, the risk to ecological or human receptors exposed to it.  The US Army Engineering Research and Development Center is developing guidance for determining risk-based suitability of dredged for beneficial uses.  The goal is to facilitate a consistent approach for chemical and biological exposure testing of dredged material proposed for beneficial use and provide the basis for scientifically sound, risk-based decisions concerning suitable beneficial use alternatives.  This will lead to cost-effective and sustainable management of sediment resources while providing more opportunities for habitat development, brownfield redevelopment, and urban gardens in cities served by ports and harbors maintained by dredging.   Examples of beneficial uses and data from case studies will be presented.