Risk Management for Contaminated Sediments

Abstract

Contaminated sediments present a serious and vexing problem. The legacy of poor environmental practices related to industrial, agricultural, and residential uses of chemicals, waste water treatment, storm water management, as well as numerous other activities affecting water quality are evident in the current challenges facing public and private organizations addressing the risks posed by contaminated sediments. Managing these risks involves detailed consideration of a complex set of processes (e.g., physical, chemical, biological, socioeconomic, etc.) operating over broad spatial and temporal scales. Large uncertainties related to these processes cloud projections about the future performance of remedies. The number of technologies that are currently available for application at contaminated sediment sites is limited to a small number of variations of dredging, capping, treatment (both in situ and ex situ) and monitored natural recovery (MNR). The economic and environmental costs of managing contaminated sediment risks are large (e.g., project costs for each of the Fox and Hudson River cleanup projects in the United States are pushing 1 billion). Sediment cleanup projects are further complicated by the diverse range of policies, perspectives, risk attitudes and personal values that pertain to risk management decisions. Government institutions, private organizations and local communities face a number of difficult problems connected to risk management for contaminated sediments. Our purpose here is to analyze the risk management problem posed by contaminated sediments, present a series of guidelines for advancing risk management practice, and describe the path toward more effective risk management solutions.