Dredging Operations and Environmental Research: Focus on Contaminated Sediment

Contaminated sediments, particularly those containing chlorinated hydrocarbons such as dioxins, pose a potential threat to the environment and human health arid significantly affect the U.S. Army Corps of Engineers navigation dredging program, causing significant project delays and management cost increases. Contaminated sediments unsuitable for conventional disposal may be confined, contained, treated, or simply not dredged. Research under the USACE Dredging Operations and Environmental Research (DOER) program is underway to address the most pressing problems related to contaminated sediments management. The objective of the Contaminated Sediments Focus Area under DOER is to reduce cost and improve the reliability and acceptability of dredging, placing, managing, and controlling contaminated dredged material. The research addresses aspects of the problem related to screening, assessment, and management, with emphasis on those solutions most applicable to the navigation-dredging program. Screening efforts include development and verification of methods for low-cost, rapid, and interpretable biological screening methods to reduce the number of chemical analyses, and quickly identify contaminated sediments and marginally contaminated dredged material. Improved screening procedures are also being developed for contaminant pathway evaluations. Assessment efforts are mainly concerned with field verification of contaminant pathway and biological testing approaches for contaminated sediments developed under other research programs such as the USACE Long Term Effects of Dredging Operations (LEDO) program. The management options most often used for contaminated sediments from navigation projects are Confined Disposal Facilities (CDFs) and subaqueous capping. Significant work is underway for management of contaminated dredged material in CDFs including contaminant control, treatment, and removal technology and reuse of marginally contaminated sediments from existing confined disposal facilities (CDFs). This paper provides an overview of the DOER Contaminated Sediments Focus Area, a description of the research efforts underway, and how the completed research benefits the USACE navigation dredging program.