Office of Pollution Prevention and Toxics
U.S. Environmental Protection Agency
401 M Street SW
Washington, DC 20460
January 30, 1997
This document has been subjected to internal review at the U.S. Environmental Protection Agency (US EPA); however, the contents of this document do not necessarily reflect the views and policies of the EPA, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. This document is intended only as an informative summary document of the PCB experience in the United States.
6.0 RESULTS OF U.S. POLICIES
PCBs are found in many different geographic locations in air, water, and soil, and are environmentally persistent (i.e., remain in the environment because they break down very slowly). PCBs can be toxic to people if exposed, in part because they bioaccumulate in the food chain (i.e., their concentration increases as they move from simple aquatic life forms, to fish, to humans). The U.S. has developed comprehensive regulations and policies for managing PCBs and for the use, storage, treatment/destruction, and disposal of PCBs. Often, the regulatory requirements are based on PCB concentration. These policies seek to minimize exposure to PCBs from all known sources, including PCBs that may be found in air, water, soil, and food; the workplace; equipment and other products that might contain PCBs; and sites contaminated with PCBs. Environmental cycling (i.e., between air, water, and soil) is thought to be the current, major source of PCBs [14].
Releases of PCBs have been successfully controlled, as evidenced by reductions of PCB concentrations in air, water, soil, and food over the years since PCB production stopped in 1977, and in products being used that contain PCBs [14,16]. Data indicate a trend towards decreasing use and storage of PCB-contaminated equipment, including capacitors and transformers, as well as a decrease in the numbers of PCB containers stored and the amounts of PCBs stored in bulk (see Figure 2). A corresponding trend towards increased disposal of PCBs also exists; that is, the amounts of capacitors, transformers, bulk PCBs, and PCB containers disposed has increased over the years (see Figure 3).
Additional information regarding emissions reductions, cleanup of PCB-contaminated sites, and storage and disposal capacity are discussed below.
6.1 Emissions Reductions
PCB concentrations in air have declined somewhat since the early 1980s [14]. Because PCBs are no longer manufactured in the U.S., industry production is no longer a source of PCB air emissions (except for small amounts of fugitive emissions). No such direct releases were reported in 1988 [14]. A large amount of PCBs are destroyed each year by incineration, and small amounts of PCBs may be released into the atmosphere during incineration. Emissions to air may also emanate from landfills due to evaporation. The amount of PCBs released into the air by incinerators and landfills is relatively small compared to the current major source of PCBs into the atmosphere, which is the redistribution of PCBs already present in soil and water [14].
6.2 Cleanup of PCB-Contaminated Sites
Approximately 255 of the 29,461 hazardous waste sites identified in the U.S. for cleanup contain PCBs as the predominant waste, and these contain approximately 34 million cubic yards of contaminated PCB material. For approximately 150 of these sites, agreements have been signed regarding remediation measures to be taken at the sites [17].
As of 1991, incineration had been selected as the cleanup technology at 65 hazardous waste sites with PCB-contaminated soil or sediment. As of 1992, thermal desorption was selected as the cleanup technology at seven such sites; chemical dehalogenation at three sites; and solvent extraction at four sites.
In 1992, in demonstration projects only (i.e., conducted at pilot- or full-scale at a limited number of sites), the U.S. EPA identified several soil washing systems; four solidification/stabilization systems; one vitrification technology (now commercially permitted), and two bioremediation systems as reportedly capable of treating PCBs in soil and sediment.
6.3 Storage and Disposal Capacity
A Canadian report states that "conversations with [U.S.] facility managers indicate that there is no shortage of commercial storage capacity in the United States" [16]. Disposal capacity also appears to be adequate, except for radioactive PCB wastes; as of 1994, over 50 million tons of radioactive PCB wastes were in storage awaiting disposal, and radioactive PCB wastes were being generated at a rate in excess of 5 million tons per year [17]. In almost all other instances, permitted disposal facilities are operating below their maximum or permitted capacity [16]. Incinerators are operating at approximately 57 to 75 percent of permitted capacity, and close to 14 million cubic yards of landfill space is or soon will be available [16]. The remaining capacities could be used for hazardous wastes other than PCBs as well. Proposed amendments to U.S. PCB regulations regarding treatment and disposal could potentially increase the capacity while reducing disposal costs [16].