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MANAGEMENT STRATEGIES FOR DISPOSAL OF CONTAMINATED SEDIMENTS M. R. Palermo, C. R. Lee, and N. R. Francingues U.S. Army Engineer Waterways Experiment Station ABSTRACT A comprehensive and consistent strategy for selecting the most appropriate disposal alternative from an environ- mental standpoint is essential when the disposal of contam- inated or potentially contaminated dredged material is re- quired. The U.S. Army Corps of Engineers (COE) has recently developed a management strategy for use in selecting dispo- sal alternatives for materials ranging from clean sand to highly contaminated sediments. A decision-making framework has also been developed to supplement the management stra- tegy and provide a logical basis for comparison of test re- sults with standards or reference information to determine if contaminant control measures are required in a given instance. This approach been adopted as official COE policy for studies involving disposal of contaminated sediments. BACKGROUND Beginning in the early 1970s, considerable attention was focused on the potential environmental effects of dredged material disposal. The U.S. Army Corps of Engineers (COE) has since devoted major research efforts toward development of testing protocols and contaminant control measures for both open-water and confined disposal alternatives. In 1984, efforts were initiated to develop an overall management strategy based on these efforts. The management strategy presented here has been adopted by COE as an environmentally sound framework for selecting alternatives for the disposal of dredged material with any level of contamination. Over 95 percent of the total volume of material dredged in the United States is considered noncontaminated. However, the potential presence of contamination has generated concern that dredged material disposal may adversely affect water quality and aquatic or terrestrial organisms. Since many of the waterways are located in industrial and urban areas, sediments may be contaminated with wastes from these sources. In addition, sediments may be contaminated with chemicals from agricultural practices. Since the nature and level of contamination in sediment vary great- ly on a project-to-project basis, the appropriate method of disposal 200

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201 may involve any of several available disposal alternatives. Further, control measures to manage specific problems associated with the pre- sence or mobility of contaminants may be required as a part of any given disposal alternative. An overall management strategy for dis- posal of dredged material is therefore required. Such a strategy must provide a framework for decision making to select the best possible disposal alternative and to identify appropriate control measures to offset problems associated with the presence of contaminants. The lead responsibility for the development of specific ecological criteria and guideline procedures regulating the transport and disposal of dredged and fill material was legislatively assigned to the U.S. Environmental Protection Agency (EPA) in consultation or conjunction with the COE. The enactment of various U.S. laws concerned with the transport and disposal of dredged and fill material, required the COE to participate in developing guidelines and criteria for regulating dredged and fill material disposal. The focal point of research for these procedures is the Dredged Material Research Program (DMRP), which was completed in 1978; the ongoing Dredging Operations Technical Sup- port (DOTS) Program and the Long-term Effects of Dredging Operations (LEDO) Program; and the COE/EPA Field Verification Program (FVP). Scope The management strategy presented here is based on findings of research conducted by the COE, EPA, and others, and experience in act- ively managing dredged material disposal. Approaches for evaluating potential for cont~minant-related problems, testing protocols, and the applicability of various disposal alternatives are discussed. Proce- dures for conducting tests or for design and implementation of manage- ment strategies are not presented but are appropriately referenced. A more detailed presentation of the management strategy is available from the COE Waterways Experiment Station (Francingues et al., 1985~. MANAGEMENT STRATEGY The selection of an appropriate strategy is partially dependent on the nature of the dredged material, nature and level of contamination, the physicochemical nature of the disposal site environment, available dredging alternatives, project size, and site-specific physical and chemical conditions, all of which influence the potential for environ- mental impacts. Technical feasibility, economics, and other socioecon- omic factors must also be considered in the decision-making process. The technical management strategy presented here mainly considers the nature and degree of contamination, physicochemical conditions at dis- posal sites, potential environmental impacts, and related technical factors. A flow chart illustrating the strategy is shown in Figure 1. The steps for managing dredged material disposal consist of the following:

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202 1. evaluate contamination potential, 2. consider potential disposal alternatives, 3. identify potential problems, 4. assess the need for disposal restrictions, 5. select an implementation plan, 6. identify available control options, 7. evaluate design considerations, and 8. select appropriate control measures. The initial screening consists of examining available historical data and information on pollutant discharges and spills at the dredging site to determine whether there is a reason to suspect the presence of significant concentrations of contaminants. If the dredged material is clean and/or environmental impacts are within acceptable limits, conventional open-water or confined disposal methods may be used. If impacts resulting from conventional disposal techniques would not be within acceptable limits, contaminated material may be disposed by either open-water or confined methods with approp- riate restrictions. Each disposal alternative may pose problems for managing contaminated dredged material. Based on the initial evalua- tion, site-specific conditions, dredging methods, and anticipated site use, the potential contaminant problems can be identified. For open- water disposal, contaminant problems may be either water column or ben- thic related. Confined disposal contaminant problems may be related to either water quality (effluent, surface runoff, or leachate) or con- taminant uptake (plants or animals). The magnitude and potential impacts of specific contaminants must be evaluated using appropriate testing protocols. Such protocols, de- signed for evaluation of dredged material, consider the unique nature of dredged material and the physicochemical environment of each dispos- al alternative. The results of all testing are compiled and evaluated to determine the potential for environmental harm from contamination, to examine the interrelationships of the problems and potential solu- tions, and to determine what restrictions on open-water or confined dis- posal are appropriate. If impacts as evaluated using the testing proto- cols are acceptable, conventional open-water or confined disposal may again be considered. Specific environmental problems identified using the testing proto- cols must be addressed by implementation plans appropriate for the level of potential contamination. Restrictions may also be required for open-wacer or condoned atsposa. cnat could eliminate certain op- tions from consideration. Several options may be available for the selected implementation strategy. Options for controlling water column and benthic impacts include bottom discharge via submerged diffusers, treatment. contained aquatic disposal. and subaqueous canning using . _ ~ ~ ~ ~ . . ~ . ~ ~ ~ . . ~1 - are a=~1~mc~ r~1~;^r~c F^~ ^^r~1~^l i ;r~~ MA A; mr~^c~=1 ~mr~s~t~c~ ___, _______ ~ _~ ___ ___ ____ ___> ___ ~—&~ TV—a_ _~C&~—= include containment, treatment, long-term storage, and reuse. The degree of contaminant control finally selected may range anywhere between disposal in open water with no special restrictions to a com- pletely controlled confinement. , ~ Many of the technologies identified

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203 o a: Z o LU — OCR for page 200
204 are either commonly used in COE dredging activities or are presently being evaluated as part of COE's ongoing research and operations. POTENTIAL PROBLEMS AND TESTING PROTOCOLS The properties of a dredged material affect the fate of any contam- inants present, and the short- and long-term physical and chemical envi- ronment of the dredged material at the disposal site influences the environmental consequences of contaminants (Gambrel! et al., 19789. These factors should be considered in evaluating the environmental risk of a proposed disposal method for contaminated sediment. Where the Whys sical and chemical environment of a contaminated sediment is altered by disposal, chemical and biological processes important in determining environmental consequences of potentially toxic materials may be affected. The major disposal alternatives are open water (subaqueous environ- ment) and confined (subaqueous, intertidal, or upland environment). A number of variations exist for each of the major alternatives, each hav- ing some influence on the fate of contaminants at disposal sites. Envi- ronmentally sound disposal of dredged material can be achieved using any of the major alternatives if appropriate management practices are employed. Water Column Although the vast majority of heavy metals, nutrients, and petrol- eum and chlorinated hydrocarbons are usually associated with the fine-- grained and organic components of the sediment (Burke and Engler, 1978), there has been little evidence of biologically significant release of these constituents from typical dredged material to the water column during or after dredging or disposal operations. Turbid- ity due to fine particulates suspension is only of limited short-term impact. Water column impacts can best be evaluated by chemical analyses of dissolved contaminants for which water quality criteria exist. The standard elutriate test is used for this purpose (U.S. EPA/COE, 1977~. Results must be considered in light of mixing and dilution. If the criteria are exceeded after consideration of mixing, a bioassay can be used to determine the potential consequences of exceeding the criteria for a short time. Benthic The DMRP results conclusively indicated that most subaqueous dis- posal in low-energy aquatic environments where stable mounding will occur will favor containment of contaminated materials. Dredging and disposal do not introduce new contaminants to the aquatic environment, but simply redistribute the sediments, which are the natural depository

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205 of contaminants introduced from other sources. The potential for accumulation of a contaminant in the tissues of an organism (bio- accumulation) may be affected by several factors, such as duration of exposure, salinity, water hardness, exposure concentration, tempera- ture, chemical form of the contaminant, and the particular organism under study. The relative importance of these factors varies. Elev- ated concentrations of contaminants in the ambient medium or associated sediments are not always indicative of high levels of contaminants in tissues of benthic invertebrates. Bulk analysis of sediments for con- taminant content alone cannot be used as a reliable index of availabil- ity and potential ecological impact of dredged material, but only as an indicator of the presence of contaminants and total contaminant con- tent. Bioaccumulation of most contaminants from sediments is generally minor. Potential benthic impacts can be evaluated by comparing contaminant concentrations in the sediments of both the dredging and disposal sites. If the concentrations are higher in the dredged material than in the disposal site sediment, a bioassay/bioaccumulation test can be used to determine the environmental consequences of the contaminant levels. Effluent Quality Dredged material placed in a confined disposal area undergoes sedi- mentation, while clarified supernatant waters are discharged from the site as effluent during active dredging operations. The effluent may contain levels of both dissolved and particulate-associated contamin- ants. A large portion of the total contaminant level is particulate associated. A modified elutriate test procedure, developed under the LEDO pro- gram (Palermo, 1986), can be used to predict both the dissolved and particulate-associated contaminant concentrations in confined disposal area effluents (water discharged during active disposal operations). The laboratory test simulates contaminant release under confined-dis- posal conditions and reflects sedimentation behavior of dredged mate- rial, retention time of the containment, and chemical environment in ponded water during active disposal. The acceptability of the proposed confined disposal operation can be evaluated by comparing the predicted contaminant concentrations with applicable water quality standards while considering an appropriate mixing zone. In some cases appropri- ate water column bioassays would be required if water quality criteria are exceeded. Surface Runoff Quality After dredged material has been placed in a confined disposal site and the dewatering process has been initiated, contaminant mobility in rainfall-induced runoff is considered in the overall environmental im- pact of the dredged material being placed in a confined disposal site.

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206 The quality of the runoff water can vary depending on the physicochemi- cal processes that occur during drying and the contaminants present in the dredged material. An appropriate test for evaluating surface runoff water quality must consider the effects of the drying process to adequately estimate and predict runoff water quality. At present there is no single sim- plified laboratory test to predict runoff water quality. A laboratory test using a rainfall simulator has been developed and is being used to predict surface runoff water quality from dredged material as part of the FVP (Lee and Skogerboe, 1983~. Leachate Quality Subsurface drainage from confined disposal sites in an upland envi- ronment may reach adjacent aquifers. Fine-grained dredged material tends to form its own disposal area liner as particles settle with per- colation drainage water, but the settlement process may require some time for self-sealing to develop. Since most contaminants potentially present in dredged material are closely adsorbed to particles, only the dissolved fraction will be present in leachates. A potential for leach- ate impacts exists when a dredged material from a saltwater environment is placed in a confined site adjacent to freshwater aquifers. The site-specific nature of subsurface conditions is the major factor in determining possible impact (Chen et al., 1978~. An appropriate leachate quality testing protocol must predict which contaminants may be released in leachate and the relative degree of re- lease. Laboratory testing protocols to predict leachate quality from dredged material disposal sites have been developed and applied, how- ever additional evaluations of available leaching procedures are needed before a leaching test protocol for confined dredged material can be recommended. These evaluations are now an ongoing COE research effort. Plant Uptake After dredged material has been placed in either an intertidal, wet- land, or upland environment, plants can invade and colonize the site. There is potential for movement of contaminants from the dredged mate- rial into plants and then eventually into the food chain. A test protocol for plant uptake was developed under the LEDO program based on the results of the DMRP. This procedure has been applied to testing a number of contaminated dredged materials and has given appropriate results and information to predict the potential for plant uptake of contaminants from dredged material (Folsom and Lee, 1981, 1983). Animal Uptake Animals have also been known to invade and colonize confined

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207 dredged material disposal sites. In some cases, prolific wildlife hab~- tats have become established on these sites. Concern has developed re- cently on the potential for animals inhabiting either wetland or up- land, terrestrial, confined disposal sites to become contaminated and contribute to the contamination of food chains associated with the site . A test protocol is being tested under the FVP that utilizes an earthworm as an index species to indicate toxicity and bioaccumulation of contaminants from dredged material (Simmers et al., 1983~. Other Impacts Potential impacts could arise from flammable.or noxious emissions released from the dredged material during dredging and disposal opera- tions. Standard safety precautions will eliminate adverse human health effects and are normally required under contract specifications. SELECTION OF A DISPOSAL ALTERNATIVE Disposal alternatives are divided into general classes: open water' confined, open water with restrictions, and confined disposal with restrictions. Disposal alternatives with restrictions are used whenever results of the testing protocols indicate they are needed. Conventional disposal alternatives are well documented in DMRP reports (Herner and Co., 1978) and are described only briefly in this section. The preference of open-water disposal over confined disposal, or vice versa, is dependent on many factors other than contaminants, as dis- cussed earlier. Open-Water Disposal This disposal alternative involves conventional open-water disposal techniques. This alternative would be selected if the initial evalua- tion and testing protocols as discussed earlier indicated that water column and benthic effects are acceptable. Dredged material can be placed in open-water sites by direct pipe- line discharge, hopper dredge discharge, or dumping from scows. For conventional open-water disposal, no special placement techniques are used and the material is normally discharged at a selected point within a designated disposal site. Ocean open-water disposal sites are designated using a set proce- dure (EPA, 1977~. Criteria for site designation include storage capac- ity requirements and chemical/biological considerations. Procedures for site selection are under review with the objective of improving the efficiency of the overall site designation process. The capacity of open-water disposal sites is determined by the vol- ume of accumulated material that can be placed without exceeding the designated site boundaries or exceeding water-depth constraints.

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208 Capacity also may be determined by the assimilative ability of the waters within the designated site boundaries, i.e. , their ability to reduce concentrations of suspended material and associated contaminants to an acceptable level. Procedures for evaluation of open-water disposal site capacity to include descent and spread of discharges, dispersion, erosion and resuspension from mounds, and consolidation of mounds is currently under study by the COE. The open-water environment is physically dynamic, and materials placed in open water will be dispersed, mixed, and diluted to some degree. Therefore, all evaluative procedures must be interpreted in light of the mixing expected at the disposal site. Any of several methods or models (Holliday et al., 1978) may be used to estimate the maximum concentration of the liquid and suspended particulate phases found at the disposal site after initial mixing. Confined Disposal Conventional confined disposal consists of placing or pumping the dredged material into a diked containment area where the material set- tles and consolidates. The area should be designed to provide good sed- imentation and sufficient volume for storage (Palermo et al., 1978~. The supernatant water is discharged over a weir, which is designed to maintain good effluent quality by minimizing resuspension of settled material. If the turbidity of the effluent exceeds applicable water quality standards, a chemical clarification system may be used for additional solids removal (Schroeder 1983~. Following completion of the disposal operation, the site should be managed to promote consoli- dation and drying (Haliburton, 1978~. The containment area can then be used for additional disposal, mined for productive use of the material, or returned to the sponsor for other uses (Montgomery et al., 1978~. Open-Water Disposal with Restrictions In cases where testing protocols indicate that water column or ben- thic effects will be unacceptable when conventional open-water disposal techniques are used, open-water disposal with restrictions may be con- sidered. This alternative involves the use of dredging or disposal techniques that will reduce water column and benthic effects. Such techniques include use of subaqueous discharge points, diffusers, sub- aqueous confinement of material, or capping of contaminated material with clean material. The same basic considerations for conventional open-water disposal site designation, site capacity, and dispersion and mixing also apply to open-water disposal with restrictions. Submerged Discharge The use of a submerged point of discharge reduces the area of expo- sure in the water column and the amount of material suspended in the

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209 water column and susceptible to dispersion. The use of submerged dif- fusers also reduces the exit velocities for hydraulic placement, allow- ing more precise placement and reducing both resuspension and spread of the discharged material. Considerations in evaluating feasibility of a submerged discharge and/or use of a diffuser include water depth, bot- tom topography, currents, type of dredge, and site capacity. Diffusers have been successfully demonstrated in the Netherlands and in the United States (Haves et al., 1988~. Subaqueous Confinement The use of subaqueous depressions or borrow pits or the construc- tion of subaqueous dikes can provide confinement of material reaching the bottom during open-water disposal. Such techniques reduce the areal extent of a given disposal operation, thereby reducing both phys- ical benthic effects and the potential for release of contaminants. Considerations in evaluating feasibility of subaqueous confinement include type of dredge, water depth, bottom topography, bottom sediment type, and site capacity. Subaqueous confinement has been utilized in Europe and to a limited extent by the COE New York District. Precise placement of material and use of submerged points of discharge increase the effectiveness of subaqueous confinement. Capping Capping is the placement of a clean material over material consi- dered contaminated. Considerations in evaluation of the feasibility of capping include water depth, bottom topography, currents, dredged mate- rial and capping material characteristics, and site capacity. Both the Europeans and the Japanese have successfully used capping techniques to isolate contaminated material in the open-water disposal environment. Capping is also currently used by the COE's New York District and New England Division as a means of offsetting the potential harm of open- water disposal of contaminated or otherwise unacceptable sediments. The London Dumping Convention has accepted capping, subject to careful monitoring and research, as a physical means of rapidly rendering harmless contaminated material dumped in the ocean. The physical means are essentially to seal or sequester the unacceptable material from the aquatic environment by a covering of acceptable material. The efficiency of capping in preventing the movement of contami- nants through this seal and the degradation of the biological community by leakage, erosion of the cover (cap), or bioturbation are being ad- dressed by research under the LEDO program. The engineering aspects of cap design and placement are being addressed under the COE's Dredging Research Program (DRP). It is possible that techniques and equipment can be developed that will provide a capped dredged material disposal area as secure from potential environmental harm as upland confined disposal areas. The capping technique for disposal of dredged material has potential for relieving some pressure on acquiring sites for

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210 confined disposal areas in localities where land is rapidly becoming unavailable. Chemical/Phys ical/Biological Treatment Treatment of discharges into open water may be considered to reduce certain impacts. For example, the Japanese have used an effective in- line dredged material treatment scheme for highly contaminated harbor sediments (Barnard and Hand, 1978~. However, this strategy has not been widely applied and its effectiveness has not been demonstrated for solution of the problem of contaminant release during open-water disposal. Confined Disposal with Restrictions Site Selection and Design Conventional confined disposal methods, described previously, can be modified to accommodate disposal of contaminated sediments in new, existing, and reusable disposal areas. The design or modification of these areas must consider the problems associated with contaminants and their effects on conventional design. Site location is an important consideration since it can mitigate many contaminant mobilization problems. Proper site selection may re- duce surface runon and therefore contaminated runoff and contaminant release by flooding. Groundwater contamination problems can be offset through selection of a site with natural clay foundation instead of a sandy area and through avoidance of aquifer recharge areas (Gambrel! et al., 1978~. Careful attention to basic site design as discussed previously will aid in implementing many of the controls outlined. Retention time can be increased to improve suspended solids removal and, therefore, contam- inant removal. Additional pending depth can also improve sedimenta- tion. Decreasing the weir loading rate and improving the weir design to reduce leakage and control the discharge rate can also reduce the suspended solids and contaminant concentration of the effluent. Dewa- tering should be examined carefully before selecting a method, since it promotes oxidation of the material and thereby increases the mobility of certain contaminants (Gambrel! et al. 1978~. Care must also be taken to reduce loss of contaminated sediment by erosion during drain- age and storm events. Four options are considered available for confined disposal with restrictions. These options include I. containment--dredged material and associated contaminants are contained within the disposal site; 2. treatment--dredged material is modified physically, chemically, or biologically to reduce toxicity, mobility, etc.; 3. storage and rehandling--dredged material is held for a temporary

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211 period at the site and later removed to another site for ulti- mate disposal; and 4. reuse---dredged material is classified and beneficial uses are made of reclaimed materials; Obviously, combinations of the above options are available for a par- ticular dredging operation. Effluent Controls Effluent controls at conventional confined disposal areas are gener- ally limited to chemical clarification. The clarification system is de- signed to provide additional removal of suspended solids and associated adsorbed contaminants as described in Schroeder (1983~. Additional con- troLs can be used to remove fine particulates that will not settle or to- remove soluble contaminants from the effluent. Examples of these technologies are filtration, adsorption, selective ion exchange, chemi- cal oxidation, and biological treatment processes. Beyond chemical clarification, only limited data exists for treatment of dredged mate- rial (Gambrel! et al., 1978~. Runoff Controls Runoff controls at conventional sites consist of measures to prevent erosion of contaminated dredged material and dissolution and discharge of oxidized contaminants from the surface. Control options include maintaining ponded conditions, planting vegetation to stabilize the surface, liming the surface to prevent acidification and to reduce dissolution, covering the surface with synthetic geomembranes, and/or placing a lift of clean material to cover the contaminated dredged material (Gambrel! et al., 1978~. Leachate Controls Leachate controls consist of measures to minimize groundwater pol- lution by preventing mobilization of soluble contaminants. Control measures include proper site selection as described earlier, dewatering to minimize leachate production, chemical admixing to prevent or retard leaching, lining the bottom to prevent leakage and seepage, capping the surface to minimize infiltration and thereby leachate production, vege- tation to stabilize contaminants and to increase drying, and leachate collection, treatment, or recycling (Gambrel! et al., 1978~. Control of Contaminant Uptake Plant and animal contaminant uptake controls are measures to pre- vent mobilization of contaminants into the food chain. Control meas- ures include selective vegetation to minimize contaminant uptake,

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212 liming or chemical treatment to minimize or prevent release of contami- nants from the material to the plants, and capping with clean sediment Or excavated material (Gambrel! et al., 1978~. Other Controls The control of gaseous emissions that might present human health hazards can consist of physical measures such as covers, vertical bar- riers, control trench vents, pipe vents, and gas-collection systems. Wind-erosion control of contaminated surface materials is another type of management or operating control to minimize transport of contami- nants off site. Techniques for limiting wind erosion are generally similar to those employed in dust control and include physical, chem- ical, or vegetative stabilization of surface soils (U.S. COE, 1983~. Many of the contaminant controls described in the preceding para- graphs are directly applicable to the control of highly contaminated sediments. These controls will be extremely site specific. Special considerations that are based on the physical nature and chemical composition of the dredged material will be required to effectively design a confined disposal facility. For example, some contaminated dredged material may require in-pipeline treatment prior to discharging the material into the containment facility. Similarly, if the facility requires a bottom liner system, the liner materials (synthetic membrane or clay) must be chemically compatible (resistant) with the dredged material to be placed on them. Special compatibility testing will be needed for selection of appropriate liner materials. Other require- ments such as leachate detection and monitoring are likely due to the potentially adverse environmental effects of the liner leaking. DECISION -MAKING FRAMEWORK A decision-making framework has been developed that utilizes the management strategy described above and incorporates the results from the suite of test protocols (Lee et al., 1986~. Reference information and data from the test protocols are used to make the decisions called for in the framework. Detailed procedures for using the framework and example applications using data from reference sites and testing protocols are found in Lee et al. (1986~. Responsibility for Local Authority Decisions There are certain decisions that must be made initially and then periodically within the decision-making framework that are the sole responsibility of the local authorities. These local authority deci- sions (LADS) are required to initially set specific goals to be achieved. For example, a LAD must establish the environmental quality ultimately desired at the site and the rate at which this goal is to be achieved. A LAD must determine whether or not to consider mixing zones

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213 when test results exceed reference site values or water quality crite- ria. A LAD must determine the appropriate reference Biters) for test result comparisons in the decision-making framework in order to achieve the ultimate and intermediate goals. The selection of reference sites can vary from the actual disposal site to a pristine background site. This selection is dependent on the goal established for the area such as a goal of nondegradation (reference site is disposal site) or cleaner-than-present condition (reference site is pristine background site) or some other goal. The clear identification of the ultimate and intermediate goals and selection of appropriate references to achieve them is a crucial responsibility of the local authorities and will influence the outcome of all test result interpretations. Evaluation of Respective Contaminant Pathways Evaluation of respective contaminant pathways under the framework is illustrated by flowcharts. Examples of the flow charts for the open water contaminant pathways (water column and benthic) are shown in Fig- ures 2 and 3. Similar flowcharts are available for the confined dis- posal pathways of effluent discharge, surface runoff, leachate, and direct uptake by plants and animals. Test results are compared to established numerical values where these are available and appropriate for test interpretation. When such values do not exist, the framework provides guidance on interpreting test results in comparison to results of the same test performed on a reference sediment. For each test, guidance is provided on these bases for determining whether or not restrictions on the discharge are re- quired to protect against contaminant impacts or whether further evalua- tion is required to determine the need for restrictions. In some cases, there is inadequate scientific knowledge to reach a decision solely on the basis of test results, and LAD s that incorporate both scientific and administrative judgments are required to reach a deci- sion. In such cases, guidance is given on evaluating the scientific considerations involved. In this manner, guidance is provided for systematically interpret- ing the results of each test required to evaluate potential impacts of aquatic disposal and upland disposal. Applying the systematic detailed guidance will lead to a decision that restrictions are or are not re- quired for aquatic disposal and/or upland disposal. IMPLEMENTATION COE Policy of contaminated sediments (Kelly The Management Strategy/Decision-Making Framework approach was adopted as official COE policy in 1985 for studies involving disposal ~ __,, 1985 ~ . Additional guidance on use of these approaches under COE's regulatory program was provided in 1987 (U. S . COE, 1987) . The recently adopted Dredging Regulation (33 Code of

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216 Federal Regulations 320) incorporated the strategy approaches by refer- ence. The regulation also describes the approach as the basis of a "federal standard," intended to meet environmental requirements at least cost within a consistent national framework. The technical approaches used in the management strategy have received widespread acceptance by federal and state agencies. In fact, the initial development of the decision-making framework was funded by the Washington State Department of Ecology as a part of its implementa- tion of the EPA Superfund program. Environment Canada has adopted a technical approach to disposal alternative evaluation closely patterned after the management strategy. This approach, illustrated in Figure 4, was proposed for use in evaluation of dredging projects along the St. Lawrence River (Rochon, 19859. Applications Strategy is now being applied routinely by the COE and the private sector. Recently, three studies of disposal alternatives incorporated the strategy in a comprehensive manner, utilizing testing approaches for both open-water and confined disposal: 2. 1. Indiana Harbor, Indiana, a project in COE's Chicago District involving PCB-contaminated sediment (U.S. COE Environmental Laboratory, 1987~; . Everett Harbor, Washington3 a Navy homeport project involving approximately 1 million yd of contaminated sediment (Palermo et al., 1986~; and .. New Bedford Harbor, Massachusetts, a Superfund project involving sediments highly contaminated with PCB's and metals (Francinques and Averett, 1988~. These projects are example applications of the Management Strategy/ Decision-Making Framework. Refinement Refinement of the technical approaches used in the management stra- tegy is an ongoing effort under COE research programs concerned with the environmental effects of dredged material disposal. The objectives of these efforts are to develop appropriate tests and procedures, improve accuracy of predictions, and reduce the costs of testing and evaluations. REFERENCES Averett, D. E., Palermo, M. R., Otis, M. J., and Rubinoff, P. B. 1988. Evaluation of disposal alternatives for New Bedford Harbor Superfund project. Report in preparation, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Miss.

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218 Barnard, W. D. 1978. Prediction and Control of Dredged Material Dis- persion Around Dredging and Open-Water Pipeline Disposal Opera- tions. Technical Report DS-78-6. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Barnard, W. D. and T. D. Hand. 1978. Treatment of Contaminated Dredged Material. Technical Report DS-78-14. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Burks, S. A. and R. M. Engler. 1978. Water Quality Impacts of Aquatic Dredged Material Disposal (Laboratory Investigations). Technical Report DS-78-4. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Chen, K. Y., D. Eichenberger, J. L. Mang, and R. E. Hoeppel. 1978. Confined Disposal Area Effluent and Leachate Control (Laboratory and Field Investigations). Technical Report DS-78-7. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Cullinane, M. J., D. E. Averett, R. A. Shafer, J. W. Male, C. L. Truitt, and M. R. Bradbury. 1986. Guidelines for Selecting Control and Treatment Options for Contaminated Dredged Material Requiring Restrictions. Final Report, Puget Sound Dredged Disposal Analysis (PSDDA) Reports. Seattle, Washington: U.S. COE Seattle District, Washington State Department of Ecology and U.S. EPA Region 10. Folsom, B. L., Jr., and C. R. Lee. 1981. Zinc and cadmium uptake by the freshwater marsh plant Cyperus escul entus grown in contaminated sediments under reduced (flooded) and oxidized (upland) disposal conditions. J. Plant Nutrition 3:233-244. Folsom, B. L., Jr., and C. R. Lee. 1983. Contaminant uptake by Spar- tina alterniflora from an upland dredged material disposal site-- application of a saltwater plant bioassay. Proc. Internat. Conf. On Heavy Metals in the Environment, Heidelberg, West Germany. Edinburgh, Scotland: CEP-Consultants, Ltd. Pp. 646-648. Francingues, N., M. R. Palermo, R. Peddicord, and C. R. Lee. 1985. Management strategy for the disposal of dredged material: Contami- nant testing and controls. Miscellaneous Paper D-85-1. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Miss. Gambrell, R. P., R. A. Khalid, and W. H. Patrick. 1978. Disposal Alternatives for Contaminated Dredged Material as a Management Tool to Minimize Adverse Environmental Effects. Technical Report DS-78-8. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Haliburton, T. A. 1978. Guidelines for Dewatering/Densifying Confined Dredged Material. Technical Report DS-78-ll. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Hayes et al. 1988. Demonstration of innovative and conventional dredging equipment at Calumet Harbor, Illinois. Miscellaneous Paper EL-88-1, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Miss. Herner and Company. 1978. Dredged Material Research Program Publication Index and Retrieval System. Technical Report DS-78-23. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Holliday, B. U., B. H. Johnson, and W. A. Thomas. 1978. Predicting and Monitoring Dredged Material Movement. Technical Report DS-78-3.

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219 Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Kelly, BG P. J. 1985 (17 Dec). Policy guidance regarding management and disposal of contaminated dredged material. Water Resources Support Center, Fort Belvoir, Va. Lee, C. R. and J. G. Skogerboe. 1983. Prediction of surface runoff water quality from an upland dredged material disposal site. Proc. Internat. Conf. on Heavy Metals in the Environment, Heidelberg, West Germany. Lee, C. R., Peddicord, R. K., Palermo, M. R., and N. R. Francinques. 1986. General decision-making framework for dredged material, example application of Commencement Bay Washington. Miscellaneous Paper D-86-X. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Miss. Montgomery, R. L., A. W. Ford, M. E. Poindexter, and M. J. Bartos. 1978. Guidelines for Dredged Material Disposal Area Reuse Man- agement. Technical Report DS-78-12. Vicksburg, Miss. : U.S. Army Engineer Waterways Experiment Station. Palermo, M. R., R. L. Montgomery , and M. E. Poindexter. 1978. Guide- lines for Designing, Operating and Managing Dredged Material Con- tainment Areas. Technical Report DS-78-10. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Palermo, M. R. 1986. Interim guidance for conducting modified elutriate tests for use in evaluating discharges from confined dredged mate- rial disposal sites. Miscellaneous Paper D-86-1. U.S. Alley Engineer Waterways Experiment Station, Vicksburg, Miss. Rochon, R. 1985. Problems Associated with Dredging Operations on the St. Lawrence, Situation, Methods and Priority Areas for Research. Technical Report EPA 4/MA/1. Ottawa: Environmental Protection Service, Environment Canada. Schroeder, P. R. 1983. Chemical Clarification Methods for Confined Dredged Material Disposal. Technical Report D-83-2. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Simmers, J. W., R. G. Rhett, and C. R. Lee. 1983. Application of a terrestrial animal bioassay for determining toxic metal uptake from dredged material. Proc. Internat. Conf. on Heavy Metals in the Environment, Heidelberg, West Germany. U.S. Army Corps of Engineers (COE). 1983. Preliminary Guidelines for Selection and Design of Remedial Systems for Uncontrolled Hazardous Waste Sites. Draft Engineer Manual 1110-2-600. Washington, D.C.: COE. U.S. Army Corps of Engineers. 1987. Testing requirements for dredged material evaluation. Regulatory Guidance Letter RGL-87-8, COE, Washington, D.C. U.S. Army Corps of Engineers Environmental Laboratory. 1987. Disposal Alternatives for PCB-contaminated sediments from Indiana Harbor, Indiana. Miscellaneous Paper EL-87-9, Vols. I and II. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Miss. U.S. Environmental Protection Agency (EPA). 1977. Ocean dumping, final revision of regulations and criteria. Federal Register 42~7~. U.S. Environmental Protection Agency. 1980. Guidelines for specification of disposal sites for dredged or filled material.

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220 Federal Register 45~249~:85336-85358. U.S. Environmental Protection Agency/Corps of Engineers (EPA/COE). 1977. Ecological Evaluation of Proposed Discharge of Dredged Material into Ocean Waters, Implementation Manual for Section 103 of Public Law 92-532 (Marine Protection, Research, and Sanctuaries Act of 1972~. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station.