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Findings and Recommendations
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From page 4... ... Pending revisions of the Superfund Hazard Ranking System will facilitate the assessment and prioritization of human health and ecological risks associated with contaminated sediments. Many contaminated marine sediments are located along all coasts of the contiguous United States, both in local "hot spots" and distributed over large areas. Read the entire page →
From page 5... ... Recommendations Search for Contaminated Sites The location and extent of contaminated marine sediments have not been comprehensively assessed on a national basis to identify site-specific remediation targets. The federal government should initiate such a program to delineate areas with contaminated sediment. Read the entire page →
From page 6... ... Several contaminated sediment classification techniques were examined by the committee: sediment bioassays, sediment quality triad approach, apparent effects threshold technique, and equilibrium partitioning. Each technique is discussed in detail in a presented symposium paper (in this volume) Read the entire page →
From page 7... ... TABLE 1 Assessment of Sediment Classification Methodologies Classification method Advantages Disadvantages Bioassay Sediment Quality Triad � follows toxicological methods developed for water quality criteria � a direct measure of sediment toxicity � does not require identification of individual contaminants � does not assume a specific route of uptake � acute results available quickly � established test procedures in use for dredged material characterization � based on a combination of laboratory and field data indicating effects of actual contaminated sediments � based on observed biological effects � does not assume a specific route of chemical uptake � applicable to complex mixtures requires development of standard chronic bioassay methodologies � may be more costly than some chemical analyses � difficult to translate laboratory results to natural conditions � difficult to determine chemical effects � does not address human health impacts � results of chronic tests may not be timely � may not identify causative contaminants � limited by the availability of existing data or by the ability to collect large amounts of new data � available data may be of highly variable quality � difficult to translate laboratory results to natural conditions � does not address human health impacts � may not identify causative contaminants r Read the entire page →
From page 8... ... ~ Apparent Effects Threshold � indicators are not independent; c ovary with grain size and organic carbon content � potentially not comparable between geographic locations � does not consider chemical bioavailability from site to site � uses existing data (from field and laboratory; e.g., Sediment Quality Triad) � applicable to all chemicals and all biological effects � most useful for prioritizing contaminated areas within a large site � based on observed biological effects � does not assume a specific route of chemical uptake � applicable to complex mixtures r � limited by the availability and quality of existing data � varies with choice of biological effects indicator � relies on correlations/ may not identify causative contaminants � potentially not comparable between geographic locations � may be both over- and under-protective difficult to translate laboratory results to natural conditions � does not address human health impacts � multicompound interactions not accounted for � Indicators are not independent; c ovary with grain size and organic content Read the entire page →
From page 9... ... and sedimentwater partitioning coefficients are available 0 relies on KoCa measurements which are often variable � does not account for contaminant uptake by ingestion of particles or direct absorption/ adsorption from sediments � sediment and water may not be at equilibrium with respect to contaminant concentration � does not use toxicological data derived from the sediment of interest � assumption of constantbioaccumulation factor for various contaminants and organisms is questionable aKOc -- carbon normalized sediment-water partition coefficient. Read the entire page →
From page 10... ... A number of approaches may be needed to evaluate the significance and extent of contamination at any given site. Recommendations Improved Methodologies In order to ensure that decision making is informed and scientifically based, continued research and use of assessment methodologies should provide information to determine � a range of concentrations of chemicals in sediments that will result in biological effects, and � whether in-place sediments are causing biological impacts. Read the entire page →
From page 11... ... Furthermore, inadequate attention has been given to mammalian studies of the long-term chronic effects of ingesting contaminated fish and shellfish. Epidemiological studies of human populations living near contaminated sediment sites also have been under-emphasized. Read the entire page →
From page 12... ... Organic chemicals found in marine sediments tend to maintain relatively constant solubility and mobility potential when disposed of on land. When contaminated sediments are excavated and placed in contact with the air, relatively low concentrations of volatile organics can contaminate the air. Read the entire page →
From page 13... ... Although the models rely on highly empirical approaches, they are the best tools presently available for making predictions of sediment resuspension and transport. Empirical models for predicting the resuspension and mixing of contaminated sediments have serious limitations which include the following: 1. Read the entire page →
From page 14... ... Problems in high-energy environments should be assessed promptly. CONTAMINATED SEDIMENT MANAGEMENT STRATEGIES Findings Although the dredged material management strategy developed by the Corps of Engineers may be relevant to severely contaminated sediments, it is important from a management standpoint to differentiate them from less contaminanted sediments. Read the entire page →
From page 15... ... Examples include a variety of sediment stabilization or solidification techniques, and biological and/or chemical treatment. Recommendations Dredged Material Management Strategy Additional evaluation should be conducted to determine the applicability of the Corps of Engineers' dredged material management strategy to more severely contaminated sediments. Read the entire page →
From page 16... ... While widely applicable, there are practical limits to the feasibility of capping. Among the factors that may preclude or constrain the use of capping are water depth; low sediment density; high sediment water content; active erosional area; active navigational channel requiring periodic maintenance dredging; and the use of trawls, draglines, or oyster dredges, which would destroy the integrity of the cap. Read the entire page →
From page 17... ... Use of financial incentives through strict liability for assessment costs, remedial actions, and damages also may play an important role in source control, provided that trustees make aggressive efforts to hold responsible parties liable for releases into the environment. Technology and Information Transfer Aggressive technology and information transfer mechanisms are needed to ensure that knowledge gained and lessons learned from all remedial actions are available and accessible to managers confronting new remediation problems at federal, regional, and local levels. Read the entire page →
From page 18... ... For example, monitoring of capped areas might focus on changes of cap thickness, erosion around boundaries, and leakage of contaminants through the cap. REMEDIATION AND SOURCE CONTROL: ECONOMIC CONSIDERATIONS Findings Remedial actions are costly and become more expensive as additional levels of clean-up or treatment are pursued. Read the entire page →
From page 19... ... 4 Recommendations Use of Benefit-Cost Comparisons In view of the high cost of remedial actions in most cases, greater use should be made of benefit-cost comparisons over ecologically relevant time periods in order to place investments in this area on the same economic footing as investments in other public proj ects . Cost-Effectiveness Analysis Cost-effectiveness analysis of alternative remedial actions should consider both short- and long-term costs. Read the entire page →

From page 4...

... Pending revisions of the Superfund Hazard Ranking System will facilitate the assessment and prioritization of human health and ecological risks associated with contaminated sediments. Many contaminated marine sediments are located along all coasts of the contiguous United States, both in local "hot spots" and distributed over large areas.

Findings and Recommendations Pages 4-19

Findings and Recommendations
Pages 4-19