Dredged Materials Management Background Information

A tug pulling away from dock and turning directly over a disposal cell during the Boston Harbor Navigation Improvement Project

Background

Despite efforts to reduce point and non-point sources of pollution, sediment pollution concentrations remain unacceptably high in many coastal areas such as Boston Harbor. The problem is compounded if the sediments must be dredged to improve navigation. Options for dealing with contaminated sediments include leaving them alone, capping them with clean sediments, using them for wetlands creation or other beneficial uses, placing them in confined facilities, disposing of them at upland sites, or treating them. There are often wide variations in cost, technical uncertainty and environmental risk among these options.

The Boston Harbor Navigation Improvement Project (BHNIP) entails deepening portions of Boston's Inner Harbor, with disposal of the contaminated sediments in cells constructed in-channel and capped with 3 feet of clean sand. This is one of the first projects of its kind and there has been limited research on its underlying porcesses. Motivated by this project, a Sea Grant Marine Center involving researchers from MIT, UMass-Boston and Harvard School of Public Health was established in August 1996 to study basic physical, chemical and biological processes that take place when contaminated sediments are capped by coarser sediments. The goal is to provide a better scientific basis for assessing the technical and environmental risks of capping in relation to other disposal/isolation methods. A Technical Steering Committee composed of outside researchers, consultants and state and federal agency staff advises the Marine Center on its current and future research efforts.