Environmental scientist, U.S. Environmental Protection Agency, Chicago, IL
Pages: 10 Published: Jan 1995
In 1992, U.S. EPA, Region 5, sampled sediments within the Federal Navigation Project at Indiana Harbor, IN. Lack of a disposal site has precluded dredging since 1972, resulting in the accumulation of over 750 000 m3 of highly contaminated sediment. The Federal Project covers approximately 1.08 km2 of both enhanced and secondary sediment accumulation. The purpose of the sampling effort was to characterize these sediments under Subtitle C of the Resource Conservation and Recovery Act (RCRA). Several approaches common to regulatory characterization were considered and rejected in favor of a bathymetry based procedure. Bathymetric surveys were used to identify 14 areas of thick sediment accumulation. Such areas are indicative of reduced water velocities which favor the accumulation of finer-grained sediment having a strong tendency to be associated with higher contaminant concentrations. Samples obtained from these locations should contain contaminant concentrations that exceed the mean concentrations for the project sediments. Consequently, a regulatory decision based upon these samples should be conservative. Bathymetry may provide a mechanism to reduce the number of samples necessary to characterize large sediment volumes, while maintaining an acceptable level of confidence in any derived regulatory decision.
Indiana Harbor, sediment characterization, bathymetry, regulatory determinations, environmental media, navigation projects, dredging
Paper ID: STP15990S