CHAPTER 13 SHORT COURSE ON PCBS IN MINES

• Jurisdiction: United States

Mine Closure, Financial Assurance, and Final Reclamation
(Nov 2009)
CHAPTER 13
SHORT COURSE ON PCBS IN MINES
Dan W. Bench
U.S. Environmental Protection Agency
Denver, Colorado

ABSTRACT

Abandonment of Polychlorinated Biphenyl (PCB)-containing electrical equipment in surface or underground mines can result in PCB contamination of ground and surface waters which can contribute to local human health hazards and to the already existing PCB contamination of the ocean which is considered to be the final sink for PCBs.¹ The use of PCBs in mines has been documented during U.S. Environmental Protection Agency Region 8 mine inspections. PCBs used as dielectrics in transformers, capacitors, and fluorescent light ballasts are common throughout industry worldwide. References to regulations are to the United States PCB regulations at 40 CFR Part 761.

PCB PROPERTIES

The physical and chemical properties that make PCBs valuable commercially also make them environmentally detrimental. PCBs are very stable and resist breakdown from high temperature and aging.

There is no longer any doubt that PCBs present threats to human health and the environment. PCBs are one of the 12 chemicals targeted by the global Stockholm Convention on Persistent Organic Pollutants (POPs). "POPs are chemicals that remain intact in the environment for long periods, become widely distributed geographically, accumulate in the fatty tissue of living organisms, and are toxic to humans and wildlife. POPs circulate globally and can cause damage wherever they travel.² "

PCBs bioconcentrate^* in "phytoplankton--unicellular alga in the surface layers of fresh water lakes, rivers, and the ocean...[that] play a key role in regulating atmospheric carbon dioxide concentrations."³ "Phytoplankton is the primary food source, directly or indirectly, of all sea organisms. Data shows that PCBs affect the productivity of phytoplankton and the composition of phytoplankton communities."⁴⁵ About 50% of the world's oxygen is produced by phytoplankton in the oceans.⁶

Polychlorinated Biphenyls were first commercially manufactured in the United States in 1929 and were first regulated in 1979. A common misperception is that because the regulations banned the manufacture of PCBs in 1979, PCBs are no longer a problem and PCB-containing electrical equipment is no longer in use. This is not correct because the regulations authorized the use of PCBs in transformers, capacitors, and fluorescent light ballasts for the useful life of the equipment, much of which remains in service. Today, the mining industry still uses PCB-containing electrical equipment, some of which continues to be abandoned underground.

PCBs were manufactured in the US under the trade name Aroclor. Mixtures of PCBs and solvents were sold under the trade names that appear on the manufacturer nameplates of PCB electrical equipment. Some of the more common PCB dielectric trade names are: Pyranol, Interteen, Elemex, and Chlorextol. There are many others. They contain, on average, about 60% PCBs. The generic name for these fluids is Askarel.

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PCBs are not the only chemicals used in mines. Underground repair facilities have used chlorinated solvents such as trichloroethane, tetrachloroethene, and methylene chloride for cleaning and degreasing equipment. The release of these solvents, in addition to constituting their own threats of ground water contamination, can mobilize PCBs. Some mines maintain their own landfills which contain improperly disposed PCBs and solvents.

CAUTION

CONTAINS

PCBs

(Polychlorinated Biphenyls)

A...