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A Risk-Management Strategy for PCB-Contaminated Sediments 5 Defining the Problem and Setting Management Goals Applying the Presidential/Congressional Commission on Risk Assessment and Risk Management’s framework to manage risks at a PCB-contaminated site begins with defining the problems associated with PCBs in the sediments and putting them into their public-health, environmental, socioeconomic, and cultural contexts (PCCRARM 1997). The presence of PCBs in the sediments of a water body can cause a number of problems for the human and ecological communities that live near or in the water. Depending on the specific site, in addition to possible adverse human health effects, PCB contamination might result in a variety of problems, such as fish consumption advisories, limitations on navigable dredging, and adverse effects in wildlife. If the problems associated with the PCB-contaminated sediments are not identified appropriately at the outset of the management process, subsequent risk-assessment and management activities might be conducted, but the risks might not be wholly addressed or they might be transferred to a different community or ecosystem. Consequently, the risk-management process should begin by clearly defining the problems thought to be associated with the contamination at a particular site. Each site will be different in terms of the human health, ecological, cultural, economic, and social contexts in which the PCB problem occurs and needs to be managed (Box 5-1).
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A Risk-Management Strategy for PCB-Contaminated Sediments This chapter presents an approach that can be used at a PCB-contaminated site to recognize and define the problems associated with the contaminated sediments, determine the extent of the contamination and its sources, set risk-management goals to address the human health and environmental problems that affect the communities, assess other concerns, such as loss of income or cultural traditions, arising from the PCB contamination, and set priorities for risk management (Box 5-2). Some of the potential obstacles to implementing a risk-management strategy at the site are also briefly examined. BOX 5–1 Risk management is the process of identifying, evaluating, selecting, and implementing actions to reduce risk to human health and ecosystems. The goal of risk management is to take scientifically sound, cost-effective, integrated actions that reduce or prevent risks while taking into account social, cultural, ethical, political, and legal considerations (PCCRARM 1997). DEFINING THE PROBLEM The committee prepared this report based on the assumption that the sites at which this risk-management framework would be applied have already been identified as having PCB contamination. PCB contamination can be identified by a variety of mechanisms, such as fish sampling, national pollution dis- BOX 5–2 Defining the Problem What are the problems caused by the PCB-contaminated sediments? Are there other potential sources of the health or ecological problem? Who is affected by the problems? Who might be affected by the risk-management strategy? How big is the problem? What are the sources of the contamination? Are there other chemicals of concern? What are the risk-management goals? What are the obstacles to risk management?
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A Risk-Management Strategy for PCB-Contaminated Sediments charge elimination system (NPDES) permitting, bulk sediment analysis required as part of dredging or construction of shoreline structures, or monitoring for Clean Water Act section 303(d) to identify affected water bodies. In some instances, a site with known PCB contamination might become a concern if the criteria for designating sediments as “contaminated” or “hazardous” are lowered, and the contaminant levels at the site now exceed those criteria. Also, PCBs might not be the major cause of the immediate problems. For example, a decline in a fish population might not be the result of PCB contamination but rather overfishing. Such a possible cause should be included in the initial list of problems even if subsequent risk analysis indicates that overfishing is not the underlying cause of the decline in fish. At newly identified PCB-contaminated sites, the committee expects that the framework can be more easily applied when the problems associated with the contamination have not been determined yet and the differences among the affected parties are less pronounced. At newly identified sites, the extent of the contamination and the presence of other chemicals might not have been determined. One of the first steps in assessing the problems at a new site is conducting a preliminary site assessment to determine the extent of the contamination, the presence of any confounding factors, such as other contaminants, and sources of contamination. At many sites, contamination has been identified and work is under way to characterize the site or develop or implement a management strategy. At these ongoing sites (i.e., sites where the management process has begun), the general problems associated with the presence of PCBs in the sediments might have been identified, although their extent and severity might be disputed by some of the affected parties. Some of the problems that might be identified by the affected parties include PCB levels in fish or wildlife that have resulted in fish or wildlife consumption advisories, prohibitions against swimming, and lack of navigational dredging because of restrictions on dredged material disposal. Table 5–1a,b presents an overview of some of the information that has been collected at selected PCB-contaminated-sediment sites during the management process, including some basic site characteristics such as site size, the management goals, the levels of PCBs that have been found at the site, the presence of co-contaminants, the selected management option chosen and in some cases implemented at the site, estimated costs of the management action, and the source of the contamination. Once the affected parties have been identified (see Chapter 4), their knowledge, understanding, and concerns about the site and the problems associated with the PCB contamination should be canvassed. This information should be stated in general terms and might focus on both immediate concerns
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A Risk-Management Strategy for PCB-Contaminated Sediments (e.g., not eating fish) or long-range concerns (e.g., restoration of a habitat) as well as problems with the site in its present condition or problems that are anticipated to arise during or subsequent to its management, regardless of the risk-management strategy chosen. Furthermore, it is incumbent upon the regulators to explain to the other affected parties, the regulatory ramifications of the contamination and any regulatory processes that must, by law, be applied at the site. For example, if the site is on the National Priorities List (i.e., it is a Superfund site), the EPA RI/FS process must be applied (EPA 1999a). In the sections below, the committee identifies and provides examples of the problems and impacts that stem not only from the presence of PCBs in the sediments at a site but also those that might arise during and after risk management. The problems and impacts include not only public-health and ecological concerns but also social, cultural, and economic impacts. Not every problem is applicable to every site and risk-management strategy; furthermore, each site will have problems that cannot be anticipated. Table 5–1a,b provides an overview of selected PCB-contaminated-sediments sites. From this table, it is evident that the motivation behind the management at the majority of these sites stems from human health or ecological concerns. For instance, at Commencement Bay, the risk-management goals were the reduction of contaminant concentrations in sediments to concentrations that would support a healthy marine environment and protect the health of people eating seafood from the bay. Public-Health Problems Food chains are the most likely source of exposure for higher trophic organisms, particularly via fish consumption. As a result, consumption of contaminated fish might be perceived as the major problem on a river by the affected parties, particularly by subsistence fishermen or those for whom fishing is a cultural value. In addition to fish, consumption advisories have also been issued for other wildlife. The Massachusetts Department of Public Health issued a provisional waterfowl consumption advisory in August 1999 on the basis of PCB concentrations found in wood ducks and mallards collected near the Housatonic River (EPA 1999c). The U.S. Food and Drug Administration (FDA) limit for PCBs in poultry is 3 ppm, and the ducks had average concentrations of 7.1 ppm in breast tissue (EPA 1999c). In general, PCB concentrations in sediments have not adversely affected activities like boating because of the lack of direct contact between boaters and PCBs.
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A Risk-Management Strategy for PCB-Contaminated Sediments TABLE 5–1a Overview of Selected Sites with PCB-Contaminated Sediments Name of Site Size of Site (Area of Concern) Site Characteristics PCB Levels Other Major Contaminants Commencement Bay, WA (Projects 1, 2, and 3) Project 1:2.5 miles; Project 2:3,000 ft wide by 750 ft long (Sitcum Waterway) and (5,200 ft long by 300 ft wide (Milwaukee Waterway); Project 3:1.2 miles long by 600 ft wide (GE 1999) Intertidal areas, 7 inland waterways (GE 1999) Maximum PCB concentration at Superfund site, 25 ppm (EPA 1999b) Arsenic, cadmium, copper, lead, zinc, PAHs, beryllium, chromium, mercury, nickel selenium, silver, zinc, anilines (GE 1999) Fox River, WI (Projects 1, 2, and 3) Project 1:9 acres; Project 2:3 acres; Project 3:39 miles (GE 1999) Impounded by 12 dams and 17 locks (GE 1999) 35 soft sediment deposits from Lake Winnebago to DePere (32 miles) with an estimated PCB mass of 4,200 kg (4.63 tons); dispersed sediment deposition in the lower 7 miles with estimated PCB mass of 26,500 kg (29.2 tons) (GE 1999) Metals (mercury), PAHs (GE 1999) General Motors Central Foundry (Messena, NY) 27 acres (GE 1999) Nearshore area; St. Lawrence River, Raquette River, Turtle Creek (GE 1999) Raquette River (flows along the southern boundary of the site), maximum PCB levels of 390 ppm (EPA 1999b) Mainly PCBs (GE 1999)
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A Risk-Management Strategy for PCB-Contaminated Sediments Housatonic River, MA (Projects 1 and 2) Project 1:500 ft; Project 2:0.5 mile reach (GE 1999) Project 1: hot spot: Upper Housatonic River; Project 2: Housatonic River starting in Pittsfield, MA (GE 1999) Sediment volume, 6,000 yd3 (Scenic Hudson 2000) Mainly PCBs (GE 1999) Hudson River, NY 43 miles (GE 1999) 17 major tributaries drain 13,365 square miles of land located in eastern NY, VT, MA, and CT. The lower river is a tidal estuary (EPA 1999b) Approximately 1 million lb dispersed throughout entire Hudson River system south of Fort Edward; after dredging, 498,000 to 656,000 lb remain in river (EPA 1999b) Mainly PCBs (EPA 1999b) Lake Hartwell, SC 730 acre—Sangamo Weston/Twelve Mile Creek/Lake Hartwell (EPA 1999e) 12-Mile Creek, Lake Hartwell (GE 1999) Between 1955 and 1977, 400,000 lb PCBs discharged into Town Creek, a major tributary of Lake Hartwell (EPA 1999e) VOCS, PCE, TCE, other organics (EPA 1999b) Manistique Harbor, MI Drains 1,450 square miles; area of concern, 1.7 miles (Fox River Group 2000) Manistique Harbor, Manistique Bay, Lake Michigan (GE 1999) In 1999, concentrations of 990 ppm and 620 ppm in the dredging areas of the Harbor and the North Bay (Fox River Group 2000) Mainly PCBs (GE 1999) New Bedford Harbor, MA (Projects 1 and 2) 18,000 acres (EPA 1999d) Tidal estuary/harbor/bay (EPA 1999d) In 1989, hot spot 5 acre area containing 45% of PCBs; concentrations ranging from 4,000 ppm to over 200,000 ppm (EPA 1992) Heavy metals with concentrations from below detection to 4,000 ppm (EPA 1992)
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A Risk-Management Strategy for PCB-Contaminated Sediments Name of Site Size of Site (Area of Concern) Site Characteristics PCB Levels Other Major Contaminants Palos Verdes, CA 17–27 square miles (GE Estuary (GE 1999) 1999) Highest levels reported in the 3 square miles of sediments on the Palos Verdes Shelf (GE 1999) DDT (GE 1999) TABLE 5–1b Overview of Selected Sites with PCB-Contaminated Sediments Name of Site Selected Remediation Action Remediation Goals Cost of Remediation Source of Contamination Commencement Bay, WA (Projects 1, 2, and 3) Dredging, excavation, and treatment of all contaminated soils (GE 1999) Goal is reduction of contaminant concentrations in sediments to levels that will support a healthy marine environment and will protect the health of people eating seafood from the bay; Sediment Quality Objectives (SQOs) used to achieve goal; goal established to allow a diverse range of uses in the bay, including industrial, commercial, navigation, fisheries, and recreation (GE 1999) Project 1:$39.1 million; Project 3: $36.9 million (GE 1999) Storm water runoff, contaminated groundwater, and other industrial operations (Asarco Tacoma Smelter) (GE 1999)
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A Risk-Management Strategy for PCB-Contaminated Sediments Fox River, WI (Projects 1, 2, and 3) Hydraulic dredging (GE 1999) Demonstration dredging project, with ultimate target of 1 ppm for PCBs (GE 1999) Project 1:$2.5 million for removal, dewatering, and water treatment of 55,000 yd3; Project 2:$4 million (GE 1999) 10 or more paper mills discharged during production of carbonless copy paper, recycling of wastepaper, in addition to other sources (GE 1999) General Motors Central Foundry (Messena, NY) Hydraulic dredging, wet excavation, capping (GE 1999) Reduce PCB levels in fish (GE 2000) $10 million total (GE 2000) General Motors Powertrain facility emitted PCBs in the hydraulic fluids used in diecasting machinery. Evidence of historical discharges from an outfall pipe (GE 1999) Housatonic River, MA (Projects 1 and 2) Dry/wet excavation; commercial landfill (GE 1999) Some removal prior to PCB sampling, with additional removal based on agency field decisions regarding (1) whether remaining PCB levels pose an imminent hazard, (2) whether removal is technically practicable, and (3) whether additional removal will contribute to a long-term remedy; removal to at least 5-foot depth with potential for 8-foot based on the three criteria; unofficially, 1 ppm residual PCBs was the target (GE 1999) $4.5 million total (GE 2000) Implosion at General Electric transformer manufacturing facility (GE 1999)
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A Risk-Management Strategy for PCB-Contaminated Sediments Name of Site Selected Remediation Action Remediation Goals Cost of Remediation Source of Contamination Hudson River, NY In-place containment, reinforcement of banks (EPA 1999b) Not identified Estimated cost of full-scale hot spot dredging $34,000,000 and $55,000,000 (EPA 1999b) General Electric (GE) discharged PCBs into the river from 1947 until 1977 (GE 1999) Lake Hartwell, SC Extraction and treatment by air stripping and/or carbon adsorption and contaminated groundwater; discharge of treated water; excavation of materials contaminated with >1 ppm of PCBs (EPA 1999b) Reduce PCB levels in fish to <2 ppm FDA limit by natural recovery (GE 2000) Thermal separation, $47,900,000–63,300,000 (EPA 1999b) Site historically used for capacitor manufacturing involving dielectric fluids; waste disposal process included land-burial of off-specification capacitors and wastewater treatment sludge at site and satellite disposal facilities (EPA 1999e)
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A Risk-Management Strategy for PCB-Contaminated Sediments Manistique Harbor, MI Diver-assisted hydraulic dredging, commercial landfill (Fox River Group 2000) Reduce PCB in fish levels, reduce carcinogenic and noncarcinogenic risks to <10−4 and <1, respectively; exceptions for high-end subsistence and some high-end recreational exposure due to fish consumption (GE 2000) $10.2 million (1994) plus additional $4.24 million due to 6/7/95 Action Memorandum (GE 1999) Numerous sources, including Edison Sault Electric, Warshawsky Brothers Iron and Metal, Manistique Papers, Inc. (GE 1999) New Bedford Harbor, MA (Projects 1 and 2) Dredging, development of confined disposal facilities (CDFs) (EPA 1999d) Remove PCB mass at an optimal residual concentration-to-volume removed ratio, and reduce PCB flux to the water column (GE 2000) Project 1: Record of Decision cost estimate $12.2 million; Project 2: $120 to $130 million (GE 1999) Factories located along the Acushnet River discharged industrial processed wastes from the 1940s to the late 1970s (GE 1999) Palos Verdes, CA Natural attenuation proposed for biodegradation of DDT, based on 1998 University of Michigan study, capping (GE 1999) Not identified Not identified Transport of DDT through the Los Angeles sanitary sewer system; PCBs discharged from a Westinghouse Electric facility (or facilities) (EPA 1992)
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A Risk-Management Strategy for PCB-Contaminated Sediments Ecological Problems The presence of PCBs in sediments can also have impacts on wildlife populations, particularly threatened and endangered species that are already considered to be at risk. For example, declines in mink populations in the southeastern United States have been attributed to PCB contamination (Osowski et al. 1995). Although increases in PCB concentrations in fish are generally considered to pose a human health risk to people that consume them, PCB exposure might also result in reproductive impairments in freshwater fish and in other aquatic organisms. Reduced numbers and species of aquatic organisms have been observed below seep areas in a PCB-contaminated marsh at Sullivan’s Ledge in New Bedford, Massachusetts (EPA 1999b). Social Impacts The presence of contaminated sediments at a site and their management are not without social impacts on a community. The presence of contaminated sediments in a community might prevent the use of the water body for recreational activities, such as boating or swimming. Playgrounds near the Housatonic River in Massachusetts required the removal of contaminated soils before children could use them. The affected community might perceive that their drinking water is contaminated or unsafe that their community is unhealthy as a result of the contamination. They also might be more fearful for their own health and that of their children. The presence of contamination might also lead to divisiveness among neighbors, some believing that the contamination is of concern and others believing that it is not. Divisiveness might also occur between those who are concerned about the effects of the contamination on wildlife and those who do not consider the ecosystem to be at risk. Because some management efforts at PCB-sediment sites involve the use of heavy construction equipment over long periods of time (many years in some cases), the community might be subjected to increased noise pollution caused by the remediation (e.g., dredging) and disrupted by the trucks hauling sediments and the digging of holding ponds. Increased air pollution can result from a greater number of vehicles, road dust, and site operations, and new roads or other facilities might have to be built causing further disruption to the community. There might be fears of contamination leaking from holding and dewatering areas, spills from the trucks that transport the sediment, or leaks from landfills.
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A Risk-Management Strategy for PCB-Contaminated Sediments Cultural Impacts The most significant impacts of PCB-contaminated sediments and risk-management efforts on culture occur in those populations whose identity is linked in some way to fishing. For American Indian and other groups for whom fishing is an integral cultural value, the main concerns include the health of families, impacts on the health of aquatic and terrestrial wildlife, and severe disruptions in their way of life. For populations who are not American Indian, impacts are most likely to be felt by communities and individuals whose livelihood and way of life revolve around commercial fishing and consumption of seafood. For American Indian populations, the bans on consumption of PCB-contaminated fish, turtles, and shellfish have produced serious disruptions in the normal pattern of life on some reservations (Carpenter 1995). American Indians who once were able to subsist at least in part by fishing have been forced to obtain food from sources outside their communities. Cultural practices that involve fishing traditions over generations in some cases can no longer be practiced. The nearness of PCB-contaminated sites to Indian lands and landfill disposal of PCB sediments near tribal lands have had a disruptive effect on the way of life for some American Indians. The inability of those Indian nations to have a decision-making role with regard to PCB management has left some with a sense of alienation and inability to control an important aspect of their future (Akwesasne Research Advisory Committee 1999). Other less obvious impacts on cultural practices include possible avoidance of breast-feeding in populations exposed to PCB-contaminated fish. In the United States, human breast milk from individuals in the general population commonly contains PCBs. At least a quarter of samples tested had PCBs concentrations at or above 1.5 ppm, the FDA action level for food-grade commercial milk (21 CFR Section 109.30). Health-care workers faced with counseling women about breast-feeding have a difficult dilemma, because the impact of avoiding breast-feeding might be more detrimental to infant health than the possible negative impacts due to PCB exposure. Women who have a cultural, social, or economic inclination toward breast-feeding might find recommendations to avoid the practice unacceptable. Economic Impacts The economic implications of PCB contamination and subsequent risk-management efforts can affect commercial activities in several ways. The presence of PCB-contaminated sediments might have impacts on nearby and even distance communities. Individuals and businesses whose income is
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A Risk-Management Strategy for PCB-Contaminated Sediments dependent on commercial fishing might feel other direct economic impacts. For example, PCB contamination of sediments in Buzzards Bay, Massachusetts, has disrupted commercial fishing in the area (Farrington et al. 1985). In addition, PCB contamination of sediments can be a costly problem for maintenance of navigational channels and development of ports and harbors. On a microeconomic level, fishing bans that restrict or prevent consumption of fish and shellfish from contaminated waters can have a financial impact on families who depend on subsistence fishing to provide a portion of their diet. PCB contamination and subsequent management activities can affect commercial, recreational and subsistence fisheries. In New Bedford Harbor, Massachusetts, total PCB-related losses to the commercial lobster fishery alone were estimated at $2.0 million (McConnell and Morrison 1986), and the loss to recreational fishing was estimated to be approximately $3.1 million (McConnell 1986). Those figures might understate losses, as they include only the cost of traveling to more distant sites to avoid contamination. Other costs, such as any potential reduction in catch, lost recreation days, or any impacts associated with fishers going out of business, are not included in these estimates. If the water body was navigable prior to contamination, costs associated with continued navigational dredging can increase as a result of disposal of contaminated sediments. Costs include dumping fees, transportation (frequently out of state) and other activities, such as dewatering. Concerns about remobilization of contaminants or the high costs of handling contaminated sediments can restrict maintenance dredging (NRC 1997). Lack of maintenance dredging might result in restrictions on vessel traffic, delays in cargo handling and shipment, and the likelihood of accidents. The resultant economic loss in shipping could be substantial at a national level. For example, in 1999, over $670 billion in imports and exports traveled through U.S. ports (DOT 2000). A loss that amounts to even a small fraction of the annual value of cargo transportation could imply large losses over time for the nation as a whole.1 PCB contamination can result in recreational losses. The total loss to recreational beach users in the New Bedford Harbor area was estimated to be between $8.3 and $11.4 million (McConnell 1986). Again, that amount includes only the losses associated with selecting alternative sites that are less desirable and more distant, thereby requiring additional travel costs. Other impacts, such as a reduction in the number of recreation days, are not included in these estimates. 1 The loss excludes both the transport of domestic commercial products and all noncommercial transportation.
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A Risk-Management Strategy for PCB-Contaminated Sediments If the contamination has resulted in a change in diet from a fish-based protein source to a less healthful diet, there might be health impacts, and thus economic costs, associated with the dietary changes such as increased risk for heart disease. PCB contamination can also result in reduction in property values for home owners living adjacent to contaminated waters and for those living near sediment disposal sites. Mendelsohn (1986) estimates that PCB contamination in New Bedford Harbor resulted in losses totaling $27.3 to $39.7 million to nearby home owners. These and other impacts can result in large economic losses to the nation as a whole.2 Concerns regarding reduced property values have been expressed by farmers who also face potentially reduced demand for their agricultural products because of consumer fears of contamination (Borden 1999). In addition, unforseen problems associated with contamination might occur. The committee learned from one meeting participant that he was unable to dispose of the zebra mussels that infested his water front because they contained such high concentrations of PCBs and were considered hazardous waste. There are also economic impacts associated with any risk-management strategy. One significant impact is on potentially responsible parties who face having to finance management activities. The large amounts of sediments that might have to be managed at a site means that the financial impact on responsible parties might be extremely high. When responsible parties are no longer capable of paying for remediation efforts, the costs for cleanups might be borne by local, state, or federal governments. In addition to the actual cost of the strategy itself, the strategies can have impacts on the broader community. For example, dredging can have economic impacts on the community beyond the cost of the dredge and crew. Increased costs can be incurred for road maintenance as a result of the transport of the sediments to hazardous waste landfills and for obtaining access to the contaminated areas if the adjacent shorelines are privately owned. Some businesses might be adversely affected by management of the sediments if the implementation of the strategy curtails access to the river (e.g., use of silt curtains) or prevents use of a navigable channel in the water because of the placement of a cap or location of a dredge. Management activities might have 2 Note that total losses cannot be determined simply by adding these numbers. Additional categories of losses might be associated with health or other effects. Furthermore, these numbers might include common elements resulting in double counting of some damages. For example, some of the losses in housing values might reflect the loss of nearby opportunities for recreational amenities.
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A Risk-Management Strategy for PCB-Contaminated Sediments a significant economic impact on marinas and other businesses that rely on recreational or commercial use of the waterway. Other costs associated with risk-management strategies include the possible need to site a hazardous waste landfill in the area and the cost of monitoring the site before, during, and after the risk-management strategy has been implemented. SITE ASSESSMENT For sites with known or suspected PCB contamination, existing information should be reviewed as part of a preliminary assessment to help identify present or historical sources of contamination, the spatial extent of contamination, approximate levels of contamination (e.g., in sediments and/or fish), evidence of possible effects to humans and the environment, and the existence of co-contaminants at the site. Although the available information oftentimes provides an incomplete characterization of the site, this preliminary assessment provides a useful starting point for the risk-management process, particularly in identifying affected parties and in assisting the affected parties to prioritize the problems and set general risk-management goals. For example, a larger site might pose more concerns, as more communities, both human and ecological, can be affected by the contamination and therefore might have more varied perceptions of the problems at a site. A small site might have fewer problems associated with it and only a few communities that are affected. Sources of PCBs In a given region, historical uses of PCBs (e.g., in the manufacture of electrical capacitors, carbonless copy paper, etc.) have often served as good indicators of potential PCB contamination. In many instances, the manufacture and use of PCBs have resulted in their release to the environment through permitted discharges or inadvertent release with subsequent sediment contamination. For example, leaking transformers may release PCBs to nearby water bodies. Although virtually all uses of PCBs in the United States were banned in 1977, PCBs continue to be released at many sites and are adding directly to PCB inventories in contaminated sediments and to elevated PCB concentrations in fish. Existing sources of PCBs might include leaching of PCB oils and contaminated groundwater from industrial sites, erosion of PCB contaminated
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A Risk-Management Strategy for PCB-Contaminated Sediments soils from the watershed, and bank erosion. In addition, low concentrations of PCBs from high-volume discharges such as municipal wastewater treatment plant discharges, combined-sewer overflows, and storm drains might also serve as significant sources of PCBs to aquatic systems. Because of the dispersal of PCBs in the atmosphere, atmospheric deposition of PCBs by wet and dry deposition and gaseous exchange might also be important at certain sites. The distinction between historical and current sources of PCBs can have a major impact on defining the extent of the contamination problems and setting risk-management goals. For example, remediation efforts at the General Electric Plant on the Hudson River at Fort Edward, New York, were complicated when PCBs were found to have entered the bedrock along the river and, in spite of the removal of tons of contaminated sediments, seepage from the bedrock continues to release many pounds of PCB into the river. Efforts to remove the PCBs from the bedrock are still in progress. Characterization of Present Contamination Sediment problems associated with PCBs occur at a variety of different types of site, for example, nearly dry sites to deep ocean, rural to metropolitan areas, and highly commercial to subsistence living conditions (see Table 5–1 for a description of selected sites). At a given site, horizontal and vertical variations in PCB concentrations are common and are dependent on the history of PCB loadings and on the temporal and spatial deposition patterns of fine- and coarse-grained sediments. For example, at the Raisin River in Michigan, PCB sediment surface concentration ranged from 11 to 28,000 ppm and subsurface concentrations ranged from 0.78 to 29,000 ppm prior to remediation (GE 2000). At the Reynolds Metals Company Superfund site in Massena, New York, on the St. Lawrence River, PCBs were detected at concentrations up to 690 ppm. In addition to PCB-sediment-sampling results, fish monitoring data can provide further information on PCB-contamination levels. For preliminary assessment, PCB concentrations in fish might serve as a more appropriate indicator of contamination since they provide a more direct measure of PCB effects on wildlife and of PCB exposures to humans consuming contaminated fish. EPA has developed national guidance for states to determine whether humans are at risk and what the local fish consumption advisories should be (EPA 2000). Preliminary review of existing information can also be used to assess the geographical extent of the problem and set risk-management goals. In a
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A Risk-Management Strategy for PCB-Contaminated Sediments situation such as the Hudson River or Commencement Bay, an appreciation of the extent of the contaminated site will help determine who should participate in setting the risk-management goals. Communities and industries above or below the actual site of major contamination might need to be involved if they are directly or indirectly affected by the contamination, or if they contribute to the problem for others. Co-contaminants The presence of co-contaminants at a site complicates the problem definition. Depending on the initial problem at the site (e.g., fish advisories or recontamination of a flood plain) and the co-contaminants at a particular site, the nature of the problem can change substantially. For example, if a site contains mercury and PCBs, as do some sites around the Great Lakes, fish advisories might reference both chemicals. However, as is evident from some recent controversy regarding the consumption of fish contaminated with PCBs and mercury by pregnant women, it might be difficult to determine whether the developmental impairments seen in their children result from exposure to the PCBs, mercury, or both chemicals, since both chemicals have been implicated as developmental toxicants (Renner 2000). The majority of PCB-contaminated sites contain other contaminants, such as polycyclic aromatic hydrocarbons (PAHs), dichlorodiphenyltrichloroethane (DDT), and heavy metals, such as mercury. The presence of co-contaminants might have a significant impact on the options for appropriate risk management, the management outcomes, and on whether a waterway is “clean” after remediation. Although cleanup at a PCB site might also reduce contamination from other materials, cleanup of all PCB sites will not necessarily render the fish edible in all parts of a watershed, because more sites are contaminated with DDT rather than PCBs. At some sediment sites that are primarily contaminated with heavy metals, PCBs are a secondary contaminant. SETTING RISK-MANAGEMENT GOALS Once the general problems have been identified for a particular site and agreed upon by the affected parties, the next step is to set priorities and determine the risk-management goals (Box 5-3). At most sites, human health concerns are the first priority, as is reflected in the number of fish consumption advisories. At some sites, wildlife might be a second priority, particularly if the wildlife are consumed by humans; at other sites, economic issues might
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A Risk-Management Strategy for PCB-Contaminated Sediments BOX 5–3 Possible Risk-Management Goals Minimize or eliminate exposure to PCBs, site co-contaminants, and remediation-related byproducts. Reduce or eliminate exposure and adverse effects due to long-term storage of PCB-contaminated sediments. Reduce or eliminate impacts on American Indian culture and life style. Mitigate habitat impacts. Prevent economic hardship to the community. Maintain or improve property values. Remove contaminated sediments. be most important. Loss of real estate values might be a concern if dredged sediments are to be disposed of on nearby land. Because there can be so many priorities, it is important that the affected parties be included in the priority-setting phase and that their values be reflected in the risk-management goals that are set. The goals might require revision as the risk-management strategy progresses, the cost and effectiveness of the strategy becomes more apparent, and trade-offs come into play. The risk-management goals should be identified early in the framework to help guide the next stage in the framework—analyzing risks. These goals should initially be defined in general (nonquantifiable) terms and relate back to the concerns and problems identified during the information-gathering stage of this process. It should be emphasized that the problems might also need to be revised as the risk assessment indicates the severity of the effects of the PCBs to human health, wildlife, or other concerns. Some possible goals might be one or more of the following: being able to eat fish from the water body, preventing recontamination of the river bank or flood plain, and being able to conduct navigational dredging. The appropriate goals depend in part upon the judgment of the affected parties, who must be involved in establishing the risk-management goals. For instance, reducing concentrations in sediments or biota might be appropriate if it is believed that conditions are likely to remain stable. However, if it is generally believed that eventual remobilization of all buried materials is inevitable, an appropriate goal might be mass removal. Knowing what the ecosystem is like now and what the affected parties want the ecosystem to be like after implementation of the risk-management strategy can help all parties develop a mutually acceptable vision for the site.
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A Risk-Management Strategy for PCB-Contaminated Sediments It is important to recognize throughout the process that the system’s ability to recover naturally should be measured against both in situ and ex situ remediation technologies to ascertain the benefits of such measures. Placing a number of constraints on achieving the management goals (e.g., specific concentrations to be achieved in fish tissue) might lead to reduced flexibility in controlling risks, thereby limiting the extent to which risks can be reduced. At this point in the framework, the actual risks at the site are unknown. The stated goals must be flexible to allow for feedback from the risk-assessment process and subsequent analysis of the management options so that, if necessary, affected parties can redefine the management goals. Risk-management goals should also be realistic. All risk-management strategies will require some level of financial investment; a degree of willingness by all affected parties to be educated about the problems; an appreciation that the process is lengthy, detailed, and at times tedious; and revisiting various stages of the framework more than once. It might be unrealistic for a community to hold out for a goal of restoring a reach of the river to preindustrial conditions, for a potentially responsible party to expect to avoid paying some or all of the costs for a problem they caused, or for a regulatory agency to expect all affected parties to immediately appreciate the legal constraints under which it operates. During the risk-management process, it might also become evident that the goals will need to be adjusted if it appears that the risk-management strategy is not achieving the initial goals. The technical options chosen might be inadequate to deal with the contamination problem, and other options will have to be explored. Furthermore, site specific processes can be very disruptive to the community, causing problems that were not initially obvious. For example, if the risk assessment indicates that the extent of the PCB contamination is greater than originally thought, the amount of sediment to be removed, if dredging is the chosen management option, can result in the treatment and transport of greater volumes of sediment, an increased number of trucks to transport the sediment, and a greater level of noise and activity for the neighboring community. Because the sediments will have to be disposed of at an appropriate site, the community near the disposal site might be concerned about the increased volume of sediment and truck traffic. That community cannot be neglected in developing the risk-management goals for a site. They will also have long-term problems and will be asked to commit to dealing with the contamination and the associated risks as well. As the framework process proceeds, it will be necessary to establish further goals, possibly of a more technical nature, and modify the general goals identified in this initial framework stage. A detailed goal that can be developed later in the framework is, for example, the level of residual PCBs that will be acceptable (if at all) after remediation.
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A Risk-Management Strategy for PCB-Contaminated Sediments One approach to ensure that the risk-management process is fair and understandable to all affected parties is to develop a decision plan before assessments begin. In these plans, a series of decision points are described in a decision tree. In some cases, the thresholds and statistical methods to be applied to data are agreed to before the risk assessment is begun. If the science is not used in an objective and ethical manner, the entire process can be subverted. It is not appropriate for any interested party to slant the results of scientific investigations to meet political, economic, or social needs. It is absolutely critical that scientists keep the results of their studies free of bias, regardless of their affiliations. CONCLUSIONS AND RECOMMENDATIONS The committee found that the impacts of PCB-contaminated sediments extend beyond traditional human health and ecological risks considered by EPA and other regulatory agencies. The committee emphasizes that societal, cultural, and economic impacts should also be considered when developing risk-management goals for the contaminated-sediment sites. All affected parties should be involved in setting these goals. Among the impacts that might affect communities are restrictions on commercial and recreational fishing that can impact local communities, such as occurred in New Bedford Harbor where PCB-contaminated sediments resulted in economic losses to the commercial lobster fishery. Cultural impacts can result when subsistence use of a resource is lost, affecting such traditions as sharing among the community or passing on indigenous knowledge to younger generations, as occurred among the Mohawk Community of Akwesasne on the St. Lawrence River. Marine transportation can be affected by restrictions on dredging due to the need to handle contaminated sediments. Preliminary site assessments should be used to identify present and historical sources of PCB releases. The spatial extent of the contamination, the concentrations of PCBs in the sediments, possible effects on humans and the environment, and the presence of co-contaminants should be considered when determining the problems at the site and possible risk-management goals. REFERENCES Akwesasne Research Advisory Committee. 1999. Superfund Clean-up Akwesasne: A Case Study in Environmental Justice. Akwesasne Task Force on the Environment Research Advisory Committee, Hogansburg, NY. Borden T.A. 1999. Testimony to NRC on PCB Contaminated Sediments. Washington County Farm Bureau, NY. November 8.
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A Risk-Management Strategy for PCB-Contaminated Sediments Carpenter, D.O. 1995. Communicating with the public on issues of science and public health. Environ. Health Perspect. 103(Suppl. 6):127–130. DOT (U.S. Department of Transportation). 2000. U.S. Foreign Waterborne Transportation Statistics. Office of Statistical & Economic Analysis, U.S. Maritime Administration, U.S. Department of Transportation. [Online]. Available: http://www.marad.dot.gov/statistics/usfwts/pr_final1999.html [July 2, 2000]. EPA (U.S. Environmental Protection Agency). 1992. EPA Proposes Cleanup for Second Portion of New Bedford Harbor Superfund Site. EPA Environmental News January 22. EPA (U.S. Environmental Protection Agency). 1999a. Risk Assessment Guidance for Superfund: Vol. 1. Human Health Evaluation Manual Supplement to Part A: Community Involvement in Superfund Risk Assessments. EPA 540-R-98–042. OSWER 9285.7–01E-P. PB99–963303. Office of Solid Waste and Emergency Response, U.S. Environmental Protection Agency, Washington, DC. March. [Online]. Available: http://www.epa.gov/oerrpage/superfund/programs/risk/ragsa/ci_ra.pdf. EPA (U.S. Environmental Protection Agency). 1999b. Superfund Public Information System (SPIS). EPA 540-C-97–003. Office of Emergency and Remedial Response, U.S. Environmental Protection Agency, Washington, DC. September. Available as CD ROM. EPA (U.S. Environmental Protection Agency). 1999c. Waterfowl Samples from Housatonic River Show Elevated Levels of PCBs; State Department of Public Health Issues Duck Consumption Advisory [Press Release]. August 27, 1999. U.S. Environmental Protection Agency, New England. [Online]. Available: http://www.epa.gov/region01/pr/files/082799a.html. [October 13, 2000] EPA (U.S. Environmental Protection Agency). 1999d. New Bedford Harbor Superfund Site Update. U.S. Environmental Protection Agency, Region 1. [Online]. Available: http://www.epa.gov/oerrpage/superfund/sites/ [August 23, 1999]. EPA (U.S. Environmental Protection Agency). 1999e. Record of Decision (ROD) Abstract. Site: Sangamo Weston/Twelve-Mile/Hartwell PCB; Location: Pickens, SC.EPA/ROD/R04–94/178. [Online]. Available: http://www.epa.gov/oerrpage/superfund/sites/query/rods/r0494178.htm [January 14, 1999]. EPA (U.S. Environmental Protection Agency). 2000. Guidance for Assessing Chemical Contaminant Data for Use in Fish Advisories. Vol. 2. Risk Assessment and Fish Consumption Limits. 3rd Ed. EPA 823-B-00–008. Office of Water, U.S. Environmental Protection Agency, Washington, DC. Farrington, J.W., R.W.Tripp, A.C.Davis, and J.Sulanowski. 1985. One view of the role of scientific information in the solution of enviro-economic problems. Pp. 73–102 in Proceedings of the International Symposium on Utilization of Coastal Ecosystems: Planning, Pollution and Productivity, 21–27 Nov. 1982, Rio Grande, Brazil, Vol. 1. N.L.Chao and W.Kirby-Smith, eds. Rio Grande, RS, Brasil: Editora da FURG. Fox River Group. 2000. Dredging-Related Sampling of Manistique Harbor—1999 Field Study. Technical Report. Prepared by Blasland, Bouck & Lee, Inc., Syracuse, NY. June. [Online]. Available: http://www.foxrivergroup.org/pdf_files/Man_2000.pdf.
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A Risk-Management Strategy for PCB-Contaminated Sediments GE (General Electric Company). 1999. Major Contaminated Sediment Site Database. Available: http://www.hudsonwatch.com/mess/. GE (General Electric Company). 2000. Environmental Dredging: An Evaluation of Its Effectiveness in Controlling Risks. Prepared by Blasland, Bouck & Lee for General Electric Company, Albany, NY. August. McConnell, K.E. 1986. The Damages to Recreational Activities from PCBs in New Bedford Harbor. Rockville, MD: National Oceanic and Atmospheric Administration. McConnell, K.E. and B.G.Morrison. 1986. Assessment of Economic Damages to the Natural Resources of New Bedford Harbor: Damages to the Commercial Lobster Fishery. Prepared for NOAA Oceanic Assessment Division, Rockville, MD. December. Mendelsohn, R. 1986. Assessment of Damages by PCB contamination to New Bedford Harbor Amenities Using Residential Property Values. Unpublished report prepared for NOAA Oceanic Assessment Division, Rockville, MD. November. NRC (National Research Council). 1997. Contaminated Sediments in Ports and Waterways: Cleanup Strategies and Technologies. Washington, DC: National Academy Press. Osowski, S.L., L.W.Brewer, O.E.Baker, and G.P.Cobb. 1995. The decline of mink in Georgia, North Carolina, and South Carolina: the role of contaminants. Arch. Environ. Contain. Toxicol. 29(3):418–423. PCCRARM (Presidential/Congressional Commission on Risk Assessment and Risk Management). 1997. Framework for Environmental Health Risk Management: Final Report. Washington, DC: The Commission. Renner, R. 2000. PCBs may mar results of in utero mercury testing. Environ. Sci. Technol. 34(19):410A–411A. Scenic Hudson. 2000. Accomplishments at Contaminated Sediment Cleanup Sites Relevant to the Hudson River: An Update to Scenic Hudson’s Report Advances in Dredging Contaminated Sediments, Poughkeepsie, NY. September.
Representative terms from entire chapter: