PCBS, MINING, AND WATER POLLUTION
Polychlorinated biphenyls (PCBs) are a group of 209 man-made structurally related chemicals manufactured in the US from 1929 until 1977, when manufacture was voluntarily discontinued. In 1978, manufacture was prohibited under the Toxic Substances Control Act (TSCA). TSCA was enacted in 1976 after the discovery that PCBs had become a worldwide environmental contaminant that had been detected in air, water, soils, and biosystems.
Despite the fact that manufacture has been prohibited in the US and many other countries, PCBs are still authorised by the PCB regulations for use in electrical equipment, primarily as dielectric fluids (or contaminants in dielectric fluids) in transformers and capacitors. The mining industry has been an extensive user of PCB electrical equipment, and some continues to be abandoned underground. When PCBs are spilled or PCB equipment is abandoned underground, the PCBs can be expected eventually to be released into the ground water with no possibility of source retrieval. This can result in water pollution for which there may be no solution.