Great Lakes Dry Cargo “Sweepings” Policy Changes

A digital sonar scanner and sample gathering machine were used to determine the presence and properties of dry cargo residues in the Great Lakes. (Photos by Ryan Cummings)

For 75 years or more, vessels carrying bulk dry cargo on the Great Lakes have washed overboard any residues of cargo thought to be non-toxic and non-hazardous. The residues include iron ore, limestone, and coal. The residues can create risks of slipping and injury for the crew and can also possibly contaminate other cargos. These “dry cargo residue” or “cargo sweeping” discharges eliminate unsafe conditions on the vessel without requiring alternatives that could involve time delays or added cost. Current environmental statutes, if strictly enforced, would prohibit these discharges. However, under an “interim enforcement policy,” discharges of dry cargo residue are permitted in defined areas of the Great Lakes.

In 2004, Congress authorized the United States Coast Guard to replace the current enforcement policy with new regulations for these incidental discharges and required the Coast Guard to begin the environmental assessment necessary to develop new regulations. The Volpe Center supports the Coast Guard in developing a viable strategy to assess the impacts of the proposed regulations and alternatives on the existing environment as well as to project how these actions may cumulatively impact that environment.

To this end, the Volpe Center assisted the Coast Guard in its activities in Lake Erie and Lake Michigan. The Volpe Center task was to characterize the physical, chemical, and biological properties of the dry cargo residues and begin analyzing their impact on the Great Lakes. Mr. Ryan Cummings of the Environmental Engineering Division was part of a scientific team that participated in sonar mapping and sediment sampling of the affected areas to determine the scope of the problem. The sediment sampling results appeared very promising in locating discharged dry cargo residue.

The Volpe Center’s contribution supports the Coast Guard in its efforts to regulate the practice of dry sweeping based on reliable environmental-impact information.