R2 PM Evaluating Short- and Long- Term Effectiveness In Sediment Remediation|
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in Ballroom 2
682 (EVI-1122-306670) Measuring Progress: What the Past Decade of Superfund Sediment Cleanups Has Taught Us.
Start time: 1:50 PM
Evison, LH1, Ells, SJ1, 1 US EPA, OSRTI, 5204G
Over the past two decades, EPA has selected remedies at over 60 Superfund sites which include removing more than 10,000 cubic yards of contaminated sediment from a water body, or capping in place or monitoring the natural recovery of more than 5 acres of sediment. Most of Superfund's large sediment sites involve removal of at least some sediment through dredging or excavation. An increasing number of sites are also evaluating and selecting in-situ approaches such as capping and monitored natural recovery, often in combination with removal of selected areas. Field work at a significant number of Superfund sediment sites is now underway or has been completed. This presentation summarizes the latest national data on types of remedies being implemented, contaminants and exposure pathways driving risk, and the cost of many of these actions. It also describes the approaches used at Superfund sites to measure short-term and long-term effectiveness and risk reduction, including the approaches recommended in EPA′s new sediment remediation guidance. From a survey of the latest available monitoring data, the benefits and challenges of sediment cleanup are noted, including conditions most conducive to achieving and maintaining sediment cleanup levels, reducing ecological and/or human health risks, and the importance of continuing efforts to reduce all sources of contamination to water bodies.
683 (MAG-1117-832542) Risk Assessment and Remedy Evaluation at Sites in North America.
Start time: 2:10 PM
Magar, V1, Wenning, R1, Sorensen, Mary2, 1 Environ International Corporation, Chicago, IL, USA2 Environ Atlanta
Human health and ecological risks are important considerations when evaluating and comparing different sediment remedy alternatives and implementing a remediation project. In waterways, remediation risks often include the destruction of aquatic habitats (primarily benthic communities), both short- and long- term effects from leaving contaminants in place and the transport of bed load or suspended contaminated sediments. Because of the dynamic nature of sediment cleanup projects, ranking the diverse risks and benefits of various sediment remediation strategies is increasingly included in engineering feasibility studies so that comparisons can be made among different remedy options using the same criteria and baseline information. Two types of risk evaluation are needed prior to environmental cleanup. The evaluation of remedy implementation risks addresses short-term engineering issues such as worker and community safety, equipment failures and accidents. The evaluation of residual risks addresses longer-term biological and environmental issues such as ecological recovery, bioaccumulation and the relative change in exposure and risks to humans, aquatic biota and wildlife. The potential risks of different remedies, particularly excavation, capping and both in-situ and ex-situ treatment processes, are often evaluated and included in remedial decision-making at sediment sites in North America. There is growing recognition among sediment managers that if the impacts predicted by a remedial action will cause more environmental harm than good, then the remedy option should not be implemented.
684 (DEK-1117-717903) Forecasting Short- and Long-term Remedy Effectiveness within an Uncertainty Context: How Quantified Uncertainty Impacts Decisions on Remedy Effectiveness.
Start time: 2:30 PM
Dekker, T1, Helfand, J1, Redder, T1, Lautenbach, D1, 1 Limno-Tech, Inc., Ann Arbor, MI, USA
Decisions about remedial alternatives at contaminated sediment sites are almost always made in the context of considerable uncertainty about future system behavior. To date, models have often been used to forecast the long-term behavior of a site, simulating changing concentrations in various system compartments, including biota, sediment, and water. While it is often acknowledged that such models are uncertain and that uncertainty increases with longer forecast times, rigorous tools for evaluating forecast uncertainty are rarely employed. In this paper, a novel method for assessing model uncertainty within the constraints of a calibrated modeling framework is presented. The generalized parameter estimation tool of Doherty (Dohery, 2004) is used to provide a diagnostic evaluation of model behavior under a range of conditions that provide different but equally acceptable correspondence to calibration targets. The model calibration and sensitivity analysis process generates a Jacobian matrix describing and quantifying model sensitivity to critical input parameters. This process, termed calibration-constrained uncertainty analysis, is then used to run a series of illustrative simulations, illustrating how: 1) A model's value can be expressed in terms of its ability to discern between the relative merits of different remedies, in terms of some measurable future benefit 2) Models can be used both to quantify uncertainty and to provide guidance as to how uncertainty could be reduced. 3) Models are useful for resolving management questions when uncertainty is sufficiently small to allow different outcomes of a given management question to be discerned. 4) Models which allow for characterization of both the expected value and the distribution of a given output allow for design of improved long-term monitoring plans, and more quantitative assessment of the achievement (or probability of achievement) of remedial targets.
685 (LIN-1117-824482) Multi Criteria Decision Analysis Tools for Evaluating Effectiveness of Sediment Remedial Alternatives.
Start time: 2:50 PM
Linkov, I1, Satterstrom, K1, Yatsalo, B2, Kiker, G3, Bridges, T4, 1 Cambridge Environmental Inc., Cambridge, MA, USA2 Obninsk State University, Russia, Russia3 University of Florida, USA4 US Army Corps of Engineers, USA
Environmental decision-making strategies for sediment management over the last several decades have evolved into increasingly more sophisticated, information-intensive, and complex approaches including expert judgment, cost-benefit analysis, risk assessment, comparative risk assessment, and a number of methods for incorporating public and stakeholder values. Multi Criteria Decision Analysis (MCDA) tools offer a scientifically sound decision analytical framework for comparison of sediment management alternatives. This work illustrates application of different MCDA methods (Multi Attribute Utility theory (MAUT), outranking, and Analytic Hierarchy Processing (AHP) for two case studies involving management of contaminated sediments (NY/NJ Harbor and Cocheco Site in NH.). These case studies were based on real but simplified sediment management problems experienced by the Army Corps of Engineers and other stakeholders. The decision model was developed based on stakeholder surveys and implemented in Decision Lab (Poutranking method), Expert Choice (AHP method), Criterium Decision Plus (MAUT/SMART approach), PRIME Decision (MAUT/SMART with intervals), and WINPRE (interval AHP). Our objective was to rank multiple sediment disposal options available in each case. Our analysis shows that even though each MCDA method and associated tools may use a unique theoretical background and calculation algorithms, they may be consistent in clustering alternatives available for environmental managers. The overall utility of this consideration is the ability to focus on the top few alternatives and eliminate underperforming alternatives from consideration. A cross-platform analysis of a multicriteria problem may be important tool for verification of robustness of crucial decision and their sensitivity.
Start time: 3:10 PM
686 (SAB-1117-814325) Finding Effective Solutions: From Comparative Risk to Environmental Benefits Analyses.
Start time: 3:50 PM
Saban, L1, 1 Windward Environmental, LLC, Seattle, WA, USA
Sediment sites offer particular challenges to managers seeking solutions to environmental remedy selection. These sites are often complex, from the nature and extent of contamination to remedy selection and soure control issues. This presentation will illustrate use of solution-orientated approaches to effective remedy selection. Some of the concepts and tools available for decision-making include residual risk analysis, comparative risk analysis of remedies, and net environmental benefit analysis (NEBA). These tools and approaches will be discussed in the context of example sites to demonstrate how they may be used in managing complex sediment sites. The timing of use will also be discussed in the context of how effective these tools may be at particular points in the decision process.
687 (GRE-1122-306134) Flexible and cost-effective fish tissue monitoring programs for the evaluation of remedy effectiveness.
Start time: 4:10 PM
Greenberg, MS1, 2, Charters, DW1, Getty, DJ3, 1 U.S. EPA-Environmental Response Team2 Wright State University, Dayton, OH3 Lockheed-Martin/REAC, Edison, NJ
Decision-oriented data from monitoring programs are essential in the evaluation of remedy effectiveness. The consideration of dynamic or adaptive decision making strategies when designing a monitoring program is important, and the program should specifically address the remedial action objectives (RAOs) of the clean-up project. Performing statistical analyses early in the in planning phase of a remedial project assists site managers by identifying various sampling options for the selection of a cost-effective, scientifically defensible monitoring program that is capable of evaluating remedy effectiveness. This presentation reviews the development of the fish monitoring program for a contaminated sediment site that is capable of documenting changes in site conditions as reflected by fish tissue concentrations. The program was designed to allow us: (1) the statistical power to detect reasonable minimum detectable differences of the mean concentrations of contaminants in fish tissue; (2) to detect a significant trend of contaminant decline in the project area fish that will allow us to predict when the risk-based RAOs can be met; (3) the data and the flexibility to make decisions on refining or reducing the sample size and/or frequency of the fish monitoring program at appropriate points after the completion of remedial action; and, (4) to minimize false expectations. The costs of long term monitoring should also be balanced with the number of samples required to show reductions in risk to ecological and human consumers of fish.
688 (STE-1117-852688) Evaluation and management of dredging residuals to meet sediment remediation and risk reduction goals.
Start time: 4:30 PM
Stern, J1, Patmont, C2, 1 King County Dept. of Natural Resources and Parks, Seattle, WA, USA2 Anchor Environmental, L.L.C., Seattle, WA, USA
A variety of recently completed remedial dredging projects show that residuals have been spread both within dredged areas and offsite. Site conditions, dredging equipment, and best management practices may all effect residual levels. A survey of recent projects demonstrates that residuals can be expected in all dredging projects to differing degrees, and can result in significant contaminant exposure within and immediately beyond the dredge prism. Residuals can potentially result in post remediation exposures up to one half the pre-remediation levels. The effective reduction in site exposures often does not meet site cleanup goals or reduce ecological or human health risks to acceptable levels. Using a mass balance-based measure of residuals from a series of well-documented dredging projects, realistic expectations of residuals can be used to plan how to anticipate and respond to residuals. We look at several recent projects with relatively moderate levels of contamination (typically 10 to 50 times the cleanup goals) and discuss how lessons learned can be incorporated into other project designs. A combination of focused re-dredging, capping, and enhanced natural recovery was implemented to effectively control exposure and achieve final cleanup goals at many of the sites. Results suggest that residuals both within and immediately adjacent to at any dredge site will need proactive planning to meet cleanup goals including risk reduction objectives. We discuss limitations with available options to address residuals and outline methods to incorporate residuals abatement into the approved project before dredging begins.
689 (KUB-1117-845842) Monitored Natural Attenuation of the Deer Lake reservoir Area of Concern.
Start time: 4:50 PM
Kubitz, J1, 1 ELM Consulting, LLC, Barrington, Illinois, USA
The Monitored Natural Attenuation (MNA) remedy for the Deer Lake reservoir Area of Concern (AOC) has been effective. Maintenance of a constant water level was the selected remedy in the 1987 Remedial Action Plan. The effectiveness of the RAP remedy has been evaluated by monitoring the uptake of methyl mercury by northern pike. Methylmercury uptake by Deer Lake pike has declined through time; the process has occurred in three steps. The 1979 to 1985 year classes of pike accumulated an average of 7 mg of methylmercury by age 3. Deer Lake pike from the 1986 to 1992 year classes took 6 years, on average, to accumulate 7 mg of methylmercury. Pike from the 1992 to 2002 year classes in Deer Lake require an average of 11 years to accumulate 7 mg or methylmercury. At present, Deer Lake pike accumulate methylmercury at the same rate as pike in Greenwood Reservoir, which is a local reference lake (Kruskal-Wallis Analysis of Variance on Ranks; Dunns Method for Median Comparisons at =0.05.
690 (SEX-1117-854877) Use of Sediment Amendment for Remediation of Organically Enriched Sediments in Ward Cove, Alaska.
Start time: 5:10 PM
Sexton, J.1, Becker, D.1, Jacobs, L.2, 1 Exponent, Inc., Bellevue, Washington, USA2 Integral Consulting, Inc., Mercer Island, Washington, USA
In 2000 and 2001, 28 acres of the bottom of Ward Cove, Alaska were remediated by amending native sediments with 15-30 cm of clean sand. The remediated areas were part of an overall area of concern identified offshore from a former pulp mill. The primary chemicals of concern were those commonly associated with organic enrichment: ammonia and 4-methylphenol. The objective of the remedial action was to 1) reduce the toxicity of the native sediments and 2) stimulate colonization by benthic macroinvertebrates by providing a clean substrate that early colonists could inhabit and begin modifying for succeeding species. It was expected that colonization would follow the classical patterns identified for organically enriched marine environments. In 2004, the first monitoring event for the remediated areas was conducted, and included evaluations of sediment chemistry, sediment toxicity (using the 10-day marine amphipod test with Eohaustorius estuarius), and benthic macroinvertebrate communities. Results of the monitoring event showed that conditions in the remediated areas had improved considerably in the 3 years since remediation occurred. Concentrations of both ammonia and 4-methylphenol were very low and amphipod survival was very high, exceeding 90 percent at most stations. In addition, benthic communities appeared to be recovering rapidly, based on multivariate analysis of community composition (i.e., using classification analysis and multidimensional scaling), evaluations of various benthic metrics (e.g., total abundance, taxa richness, dominance, abundances of major taxa), and evaluations of key indicator species (e.g., the bivalves Axinopsida serricata and Parvilucina tenuisculpta, and the polychaetes Capitella capitata and Nephtys cornuta). It was concluded that the sediment amendment process was successful in remediating the native sediments, and that benthic communities will likely continue to develop in the remediated areas in the future. The next monitoring event will be conducted in 2007.