Evaluating Sediments and Dredged Material for Beneficial Use at Poplar Island Environmental Restoration Project

摘要

The Poplar Island Environmental Restoration Project (PIERP) in the Chesapeake Bay, Maryland, is the largest beneficial use of dredged material project in the United States. Restoration planning has identified the need to better define the characteristics of dredged material that may limit its usability in habitat restoration; this includes better understanding of the physical and chemical changes in placed dredged material. An evaluation process was developed that draws from protocols for assessing suitability of dredged material for open water and upland placement, from risk assessment methodology, and from agronomy. The basis of this process is a conceptual site model using goals of the PIERP adaptive management plan as endpoints. Available information was reviewed to identify key characteristics of dredged material suitability as a substrate for habitat restoration. This included analytical chemistry, toxicity testing, and field pilot studies and surveys both specific to PIERP and from the scientific literature. Where these data were not adequate, further investigations were conducted through collection and analysis of additional sediment samples from the navigation channels and from areas within the PIERP where dredged material is in-place. Channel sediments and in-place dredged material were tested using a variety of tools including standard and effluent elutriate tests, water-column toxicity tests, plant bioaccumulation and toxicity tests, diethylenetriaminepentaacetic acid extraction, sequential extraction of metals, chemistry and grain-size analyses. These data provide a thorough characterization of substrate conditions at PIERP, as well as information and techniques that may be useful to dredged material evaluations in the future, including metals bioavailability and bioaccumulation estimates.