ABSTRACT
Several million cubic meters of sediments must be dredged annually to clear navigation channels, berths, and marinas in New York/new Jersey Harbor. An estimated 300 million tons have been dredged and discharged during the period of 1900-2000. In the past, the dredged material was disposed in a designated ocean site in the New York Bight. However, new sediment testing procedures were implemented towards the end of the 20th century and much of the harbor’s dredged material was classified as unsuitable for ocean placement. Ironically, these restrictions came at a time when the quality of harbor’s sediments is improving as a result of pollution controls imposed by the Clean Water Act and increased public awareness of the need to curb pollution of river and coastal waters. For example, with the exception of a few areas where historical contamination continues, the harbor-wide concentration of mercury has decreased to 0.70.8 parts per million, a level that is approaching the pre-industrial background level. Anthropogenic contamination of the harbor’s sediments has occurred for centuries. Contaminants from land-based sources introduced into the water either as soluble or particulate matter over the 42,000 square kilometers of the Hudson-Raritan basin end up associated with particles that settle to the bottom, primarily in artificially deepen areas such as berths and navigation channels. Development of a basin-wide and site-specific sediment management strategy is necessary to guide the continuing clean-up of new and historical contamination and the dredging program that is the lifeline of the major port on the East coast. The backbone of this strategy is the integration of data from a comprehensive field monitoring and modeling program with a parallel investigation of watershed and airshed sources and sinks using industrial ecology methodology. As an example, this paper will concentrate on one of the principal sediment contaminants: Mercury. It examines the results of a study on new and historical sources of mercury accumulation in the Harbor and presents preliminary estimates of the material balance between inputs and outputs.
