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A Risk-Management Strategy for PCB-Contaminated Sediments
TABLE 7–3 Sediment Management Options and Associated Risks
Option
Component
Goal
Feasibility Cost
Risk of Implementing
Short-Term Risk
Long-Term Risk
Socioeconomic
Institutional controls
Sever exposure pathways
Source control
Eliminate source
In situ management
Natural attenuation
Containment and degradation
Thin-layer capping
Containment
Thick-layer capping
Containment
Ex situ management
Mechanical dredging
Removal
Hydraulic dredging
Removal
Dry excavation
Removal
Pretreatment
Dewatering, size separation
Treatment and disposal
Separation or destruction
The first goal of any management activity for PCB-contaminated sediments should be to identify and, where possible, control the point and nonpoint sources that have caused and will continue to cause the contamination problem. The sources include, but are not limited to, run-off from contaminated soils, combined sewer overflows, and atmospheric inputs.
Effectively responding to the contaminated sediment at a site generally requires using options that involve multiple technological and institutional components, and the evaluation, screening, and selection of these options must consider all the components, their interrelationships, and their impacts. Seven broad rules govern the analysis of management options:
All sites require a conceptual model of the system, and the interaction of the management options with the sediments and contaminants is required.
The use of mass flows can assist in developing and testing the
