MANAGEMENT OF POLYCHLORINATED BIPHENYLS IN THE UNITED STATES

Office of Pollution Prevention and Toxics
U.S. Environmental Protection Agency
401 M Street SW
Washington, DC 20460

January 30, 1997

DISCLAIMER

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.

2.0 PRODUCTS, SOURCES, AND RELEASES OF PCBS

2.1 Product Inventory

From 1929 to 1977, the production of PCBs in the United States was approximately 700,000 tons (1.4 billion lbs) of pure PCBs [16]. Approximately 60 percent of PCBs were used in electrical applications, primarily in dielectric fluids for transformers and capacitors. PCBs also were used in hydraulic and heat transfer systems, lubricants, gasket sealers, paints, plasticizers, adhesives, carbonless copy paper, flame retardants, brake linings, and asphalt. Nonelectrical uses included gas pipelines, buildings, ships, and research.

The fate of PCBs as of 1977 is shown in Figure 1. Of the 700,000 tons of PCBs produced, 150,000 tons had been landfilled; 75,000 tons had entered the air, water, and soil; 25,000 tons had been incinerated; and 375,000 tons remained in electrical equipment. The remainder, approximately 75,000 tons, had been
exported [16].

Figure 1. PCB inventory in the United States. Source: Ref. [16]

Another estimate of PCB use in the U.S. is provided in Table 1. Of the 1.3 billion lb of PCBs used in industrial products over the period 1929-1975, approximately 50 percent was used in capacitors, 27 percent in transformers, and 9 percent in plasticizers; the remaining 14 percent was used in hydraulic systems and lubricants, heat transfer fluids, and other items. None of these items are currently manufactured using PCBs; however, electrical equipment and many other products that were produced prior to the manufacturing ban on PCBs remain in service.

Table 1 Industrial Uses of PCBs (1929-1975)

Source: Ref. [17]

The most current inventory of PCBs remaining in use in the U.S. (see Table 2) was conducted in 1988, based on a 1982 survey of 100 electric utilities and extrapolations of non-utility PCB uses. Of the 167 million lb of PCBs remaining in use in transformers and large capacitors in 1988, approximately 121 million lb (72 percent) were in transformers, and 46 million lb (28 percent) were in capacitors. When comparing the 1976 and 1988 PCB inventories, it appears that a significant decrease in the amount of PCBs in use occurred over time for both transformers and capacitors. (The number for capacitors is actually lower because small capacitors are not included in the 1988 inventory). This trend of decreased use may have continued into the 1990s, although more recent inventories have not been conducted.

2.2 Storage and Disposal Inventory of PCBs

Commercial PCB storage facilities exist throughout the U.S., many of which are also permitted PCB disposal facilities. Data on PCB storage and disposal are based on annual reports that commercial facilities have been required to submit to the EPA since 1990. Approximately 25 million kilograms (54.9 million lb) of PCB wastes (including capacitors, article containers, transformers, bulk items, and PCB containers) were in storage in the U.S at the end of 1994, as shown in Figure 2. This represents the lowest amount in storage since 1990, when EPA began tracking storage volumes [16,19].

In 1994, approximately 843 million kilograms (1.9 million lb) of PCB waste were disposed of in permitted disposal facilities, as shown in Figure 3. This represents the largest amount of PCB waste disposed since tracking of disposal began in 1990. PCB concentrations in wastes or in sources of wastes were not reported [16,19].

Table 2 PCB inventory in the United States (1988)

Note: Large quantities of electrical equipment containing PCBs have been disposed of since this inventory. However,
because disposal data do not track the source or concentration of the wastes, it is difficult to estimate a 1996 inventory
based on these numbers.

Source: Ref. [16], except * which is Ref. [18].

2.3 Sources and Releases of PCBs

The primary sources of PCB exposure are from the environment and the workplace. Breathing indoor air and consuming fish contaminated with PCBs have been identified as major sources of exposure [20]. Trace amounts of PCBs can be found in almost all outdoor and indoor air, on soil surfaces, and in surface water. The concentrations of PCBs in air, water, soil, and food have generally decreased since PCB production stopped in 1977 [14]. In the U.S., the average person may be exposed to several micrograms of PCBs per day from air, water, and food.

Air Emissions. Traces of PCBs have been found far from where they have been released [14]. Municipal waste combustion, hazardous waste incineration, and medical waste incineration account for a significant portion of reported national PCB emissions to air [20]. Additional sources of PCB emissions included treatment, storage, and disposal facilities and landfills; hazardous waste sites; steel and iron reclamation facilities (e.g., auto scrap burning); accidental releases (PCB spills and leaks, and transformer fires); and environmental sinks of past PCB contamination [20]. PCB levels in indoor air are often much higher than in outdoor air [14].

Water and Fish. PCB concentrations are generally higher in water near human activity, and near shorelines. Currently, the major source of PCBs in surface waters is from environmental cycling (i.e., from sediment, air and land). Very small amounts of PCBs can remain in water for years, and their breakdown in water generally occurs over several years. Sediments at the bottom of a water body can act as a reservoir from which PCBs can be released in small amounts to water. PCBs in fish can be hundreds of thousands of times higher than in water because the PCBs accumulate in the fish [14].

Soil. PCBs bind strongly to soil and may remain there for several years. The amount of PCBs released to soil from manufacturing facilities (e.g., via spills or into landfills) has decreased over the years. Environmental cycling (i.e., from air and water) are suspected of being the current, major source of PCBs in soil outside of disposal and spill sites [14]. The total quantity of PCB wastes in 1991 at U.S. sites identified as having PCB contamination was estimated at 382 million tons, with a possible range of between 168 and 597 million tons [17]. PCB concentrations in soils at such sites can be much higher than background levels.

Workplace Exposure. Workplace exposure to PCBs can occur during repair and maintenance of PCB transformers, accidents, fires, spills, or disposal of PCB material. Workplace exposure primarily occurs through breathing air containing PCBs and touching materials containing PCBs. Between 1981 and 1983, fewer than 2,500 people were believed to have been exposed to high levels of PCBs (e.g., above the U.S. Occupational Safety and Health Administration's 8-hr averages) in the workplace in the U.S. [14].

Household Products and Wastes. PCBs in appliance capacitors and fluorescent light ballasts are believed to be the primary source of household PCB contamination. Appliances containing electrolyte-type capacitors were found to be free of PCBs regardless of when they were manufactured [21]. A 1992 study of used white goods estimated that 10 to 25 percent of all U.S. household white goods contain capacitors with PCBs [21]. PCB-containing household hazardous wastes may represent no more than 0.01 percent of total household hazardous wastes, or a total of 210 tons per year [17].

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