PCBs get into the environment by incomplete burning, leaching from the soil, vapourizing from paints, coatings and plastics, by illegal dumping or by accident.
A broad spectrum of adverse health effects have been reported in people occupationally exposed to polychlorinated biphenyls (PCBs). These effects may be generally explained by the induction or the inhibition of the activity of a large number of enzymes which upset quantitatively normal biological processes. Carcinogenicity of PCBs has been shown in animals, experimentally exposed.
The prevalence of the adverse health effects increased with the concentration of PCBs in the working environment and thus in the workers' tissues. Reported effects are: changes in the skin and mucous membranes; swelling of the eyelids, burning of the eye, and excessive eye discharge; burning sensation and oedema of face and hands; simple erythematous eruptions with pruritus; acute eczematous contact dermatitis (vesiculo-erythematous eruptions); chloracne (an extremely refractory form of acne); hyperpigmentation of skin and mucous membranes (palpebral conjunctiva, gingiva); discoloration of finger nails; and thickening of the skin. Irritation of the upper respiratory tract is frequently seen. A decrease in forced vital capacity, without radiological changes, was reported in a relatively high percentage of the workers exposed in a capacitor factory. Digestive symptoms such as abdominal pain, anorexia, nausea, vomiting, jaundice, with rare cases of coma and death, may occur. At autopsy, acute yellow atrophy of the liver has been sporadically reported in lethal cases. Neurological symptoms such as headache, dizziness, depression, nervousness, etc, and other symptoms such as fatigue, loss of weight, loss of libido and muscle and joint pains has been found in various percentages of exposed people.
Marine mammals have a rising quantity of PCBs in their blubber.
Prior to 1976, when they were banned, PCBs were used in products ranging from electrical transformers to light bulbs to paint, glue, and cardboard. The 1500 million pounds previously manufactured worked their way into many lakes--particularly the Great Lakes and the lakes of the northeastern U.S. Because PCBs became more concentrated as they worked their way up the food chain from fish to fish, the birds that ate the fish were significantly affected. It has been estimated, for instance, that fish-eating water birds in Lake Michigan can have PCB levels in their flesh 25 million times greater than the level of the surrounding lake water.
During a conference in Washington in 1998, aimed at restricting the production of toxic chemicals and persistent organic pollutants, Russian delegates confessed that Russia would not be able to comply with the pact as Russia still produces and uses PCBs, for example in the manufacture of transformers used on their power grid. Russia had previously assured european governments that new production of these chemicals had ceased. Negotiators accepted that Russia did not have the money to convert and allowed production to continue until 2005 and postponed the destruction of the last stocks until 2020. The fact that Russia produces, uses and perhaps exports PCBs which may be more dangerous to more people than plutonium has attracted little attention.
There must be a ban on PCB production worldwide, and provisions to ensure that current stocks are managed and disposed of in an environmentally sound manner.