Richard J. Wenning, The Weinberg Group, San Francisco CA

It is widely recognized by environmental scientists and regulatory authorities that sediment is the final repository for much of the chemical contamination that enters our air, water, and soil. Contaminated sediment is one of the largest components in waterway restoration programs and a major confounding factor in TMDL and fish advisory programs. During the past twenty-five years, the United States Environmental Protection Agency (USEPA) and nearly all of the state environmental protection agencies have drafted technical guidelines and established regulatory programs to investigate, remediate, and minimize contamination of waterways. Despite these positive efforts, there have been significant disagreements among scientists regarding assessment methods and little evidence of improvement in environmental quality. Why? In this presentation, the argument is put forth that, until recently, the absence of an understanding of fundamental ecological principles has paralyzed the nation’s ability to evaluate aquatic environments and to characterize and manage contaminated sediments. Broadly speaking, the application of the CERCLA approach to soil assessment and remediation has failed to work in the aquatic environment. The top ten reasons for this apparent paralysis, in order of importance, are: poor definition of ‘screening’ versus ‘detailed’ waterway assessments; lack of consensus on sediment quality values; the failure to understand sediment geochemistry; limitations in ecological risk assessment methods; extrapolation of ecotoxicological data among freshwater, marine, and estuarine ecosystems; inadequate characterization of aquatic food webs; confounding factors in sediment toxicity assessment; inability to resolve chemical mixtures; the absence of unified state and federal sediment management policies; and, the high costs of waterway restoration. Assuming this top ten list is correct, future progress will require review and revision of current available approaches and a renewed focus on watershed and coastal zone management programs.

Charles M. Denton, Esq., Varnum, Riddering, Schmidt & Howlett LLP; R. Craig Hupp, Esq., Bodman, Longley & Dahling LLP

Who's afraid of natural resources damages? In order to understand the question, this paper will discuss what constitutes injuries to protected natural resources; how natural resources damages are assessed; and legal liability claims and defenses under the Federal Comprehensive Environmental Response, Compensation and Liability Act ("CERCLA") and comparable State laws.

Natural resources damages ("NRD") are most often associated in the public's mind with oceanic oil spills and other catastrophic events. These claims often total millions of dollars. Moreover, the NRD recoveries are in addition to corrective action and other remedial activity costs. NRD claims can be brought by federal, state and tribal trustees of the injured natural resources.

The reality is that NRD claims are not limited to newsworthy, catastrophic events. NRD claims have been and are brought by trustees for contaminated sediments, groundwater contamination, injuries to wetlands and other habitats, and land disposal. There is a broad basis for exposure to NRD claims, which often result in significant economic and ecological benefits to the trustees.

R. H. Jensen, J.A. George, S.C. Nadeau, Sediment Management Work Group

The Sediment Management Work Group ("SMWG") has developed a risk-based framework for evaluating sediment management alternatives. This framework has evolved and been refined over the past two years following discussions with multiple stakeholders including U.S. EPA, the U.S. Army Corps, the U.S. Navy, NOAA and some state regulatory agencies. The SMWG also presented this framework during the National Environmental Policy Institute’s ongoing National Sediment Dialogue. The risk-based decision-making framework first defines the key elements of a conceptual site model and then follows by applying specific risk-based remedy selection criteria.

Angela Schmidt, M.S., Alice Carberry, Ph.D, Kely Sauerland, B.A., BHE Environmental, Inc., Thomas Glueck, B.S., Fort Leonard Wood, Missouri

The military uses numerous chemicals including munitions, obscurants, fuels, lubricants, and solvents that could adversely affect the environment. These materials and their by-products may contain polycyclic aromatic hydrocarbons (PAHs). PAHs can accumulate in biota and inorganic media such as soil and sediment. PAHs vary in degree of toxicity for aquatic organisms and can cause carcinogenic effects in biota. PAHs may accumulate in sediment, where they can become bioavailable over time. This accumulation can lead to continuous exposure to PAHs by aquatic organisms even after the source is removed. In this paper, we will present preliminary results from an ongoing five-year study at Fort Leonard Wood, Missouri. This study monitors concentrations of environmental contaminants in bald eagle prey and in the environment resulting from military activities on the Installation. Several classes of environmental contaminants are being monitored; we will discuss only results obtained from PAH analyses. Paired exposure (on the Installation) and reference sites on two waterways (Roubidoux Creek and Big Piney River) were sampled. The two reference sites were located in the Mark Twain National Forest. Fish samples were analyzed for percent lipid concentration, whole-body PAH concentrations, cytochrome P450 reporter gene system activity, and concentration of PAH metabolites. Results of the initial monitoring year indicate a positive correlative relationship among these four parameters. Fish with the greatest concentration of lipids and PAH metabolites had the most active cytochrome P450 reporter gene induction. This is indicative of past exposure to PAHs. Sediment PAH concentrations varied at all four-sample locations. Fish with the greatest concentrations of PAHs were collected in locations where sediment concentrations were the highest. Second year monitoring data will be available at the time of the presentation.

Zhen-Gang Ji, Minerals Management Service, John H. Hamrick, and James Pagenkopf, Tetra Tech, Inc.

Chunhua Liu, Gradient Corporation, Jennifer A. Jay, Tufts University, Raveendra Ika, EnviTech Corporation, James P. Shine and Timothy E. Ford, Harvard School of Public Health.

Theoretical estimations and laboratory studies suggest that capping can effectively retard contaminant transport under undisturbed conditions. However, contaminated near-shore areas, commonly selected as capping sites, are frequently subjected to Submarine Groundwater Discharge (SGD). Column experiments were set up in the laboratory to study: (1). capping efficiency in the presence and absence of SGD; (2). the effects of groundwater pH, sediment depth, and groundwater flow rate on metal transport from capped contaminated sediment under conditions of SGD; (3) the effectiveness of the core analysis technique as an indicator of metal release and capping efficiency.

Results indicate that advective flow may lead to significantly higher metal fluxes than under undisturbed conditions. In the absence of SGD, capping enhanced Mo flux and initial Mn flux. This effect was more pronounced in the presence of SGD. Capping enhanced Cd flux and initial fluxes of Ni, Cu, and Zn under conditions of simulated SGD. Capping retarded Cr and Pb fluxes and steady-state Ni, Cu, Zn, and Fe fluxes in the presence of simulated SGD. However, capping efficiency decreased relative to no SGD. Elevated Mn and other metal concentrations were detected at the capping surface with simulated SGD.

Acidified groundwater discharge enhanced the mobility of all tested metals except Mo. Although much of the released metal was adsorbed by the capping material, increased metal fluxes to the overlying water were observed for Ni, Cu, Zn, and Pb. Additional sediment depth enhanced fluxes for all metals except Cd and Pb. Increased SGD rates significantly increased all metal releases.

Finally, experimental results suggest that metal concentration gradients in the sediment or capping material may not be good indicators of metal transport under conditions of advective flow.

Michael Crystal, Sevenson Environmental Services, Inc.

Dredging is an appropriate, technically sound, and cost-effective remediation and restoration action to improve sediment quality in rivers and waterways.

Active waterways and river currents; waves and wakes; sediment depth; the nature and level of contaminants; remediation cleanup goals; sampling parameters; sediment/site geotechnical properties; turbidity; resuspension; debris and obstructions; dewatering and water treatment; sediment disposal; and minimization of commercial, residential, and recreational impacts are some of the challenges that need to be addressed in the implementation of a sediment remediation project.

Successful Dredging Projects
The success stories of large complex contaminated sediment dredging projects are increasing. Six successful dredging projects are discussed. Four involved PCBs as the contaminant. Two projects were unsuccessful on the first attempt, but were completed successfully with a new project team/remediation contractor. Successful dredging projects:

Fox River, Green Bay, WI 
Cumberland Bay, Plattsburgh, NY
St. Lawrence River, Massena, NY 
River Raisin, Monroe, MI
Marathon Battery, Cold Spring, NY 
Dalecarlia Reservoir, DC

Design & Implementation
Early involvement of the remediation contractor, owner and engineer in planning and design is facilitative of meeting project sediment cleanup objectives, environmental protection concerns, and cost and schedule.

Achievable Cleanup Levels
Cleanup levels are normally specified in two ways. One is to dredge to a predetermined elevation with < a 6" to 12" over-cut; the second is a specified clean up level for contaminant reduction. For example, the Fox River Project cleanup level was 1 part per million (ppm) PCBs. If confirmatory sampling found > 1 ppm PCBs, but </= to 10 ppm, a six inch clean sand cap was required for that sub-unit.

Costs
Due to site specific conditions, dredging costs per in-situ cy ranged widely from approximately $3.00 to $84.00 cy over the six projects, as did dewatering costs and wastewater treatment costs.