Approximately 14 to 28 million cubic yards of contaminated sediments must be managed annually in the United States (one million cubic yards is roughly equivalent to 200 football fields stacked one yard high). Progress in science and engineering has advanced the nation’s ability to detect contaminants; the challenge now, however,is to foster similar advances in decision-making and clean-up strategies.
Dredging is one of the few options available for cleaning up contaminated sediments. However, the National Research Council report Sediment Dredging at Superfund
Megasites: Assessing the Effectiveness (2007) concludes that, based on available evidence, dredging’s ability to decrease environmental and health risks is still an open question. Such technical difficulties as underwater obstacles can prevent dredging equipment from accessing sediments, and dredging can uncover and re-suspend buried contaminants, adding to the amount of pollution people and animals are exposed to, at least in the short term. The report recommends that the EPA step up monitoring activities before, during and after cleanups to determine their effectiveness.Controversies over the risks and costs of sediment management interfere with the need for regular dredging, maintenance, and construction in U.S. ports, which support approximately 95 percent of U.S. foreign trade. Those controversies also hamper or sometimes completely halt clean-up plans at hundreds of contaminated marine sites. The National Research Council report
Contaminated Sediments in Ports and Waterways: Clean-up Strategies and Technologies (1997) identifies a process
for helping decision makers assess the trade-offs among the risks, costs, and benefits of dredging. The report urges that these trade-offs be presented to the public in an accessible format.