PCB

Polychlorinated biphenyls (PCBs) were used for a variety of technical purposes until they were completely prohibited in 1986. A significant volume of these PCBs found their way into the environment, and due to their high stability they can sometimes still be found there today. The measures already taken have significantly reduced PCB concentrations in the air, in soils and in the sediments of surface waters.

PCBs are poisonous, persistent, accumulate in terrestrial and aquatic ecosystems, and spread throughout the global environment via atmospheric processes. PCBs are known to have a broad spectrum of chronic toxic effects. They primarily damage the immune system and the central nervous system and have a detrimental effect on endocrine (hormonal) control mechanisms. Some PCBs have effects similar to dioxins. These substances are therefore termed dioxin-type or coplanar PCBs (cPCBs).

Banned in Switzerland

In Switzerland, PCBs have been banned from use in "open systems" since 1972. Open systems include elastic sealants, anti-corrosion coatings, paints and varnishes. In 1986, a total ban was finally placed on any form of PCB use. Despite this, 30 years after total prohibition, significant quantities of PCBs persist from usage before the ban.

Further reductions needed

A further reduction in environmental PCB concentrations must be approached on three levels:

1. Successive removal and correct disposal of any remaining sources in Switzerland. This particularly concerns the following areas:

PCBs in electrical installations and appliances

Paints and varnishes

Permanently elastic sealants

Anti-corrosion coatings

2. Identify and eliminate further sources point by point. In late 2007, high PCB levels were detected in fish from the Saane, Canton Fribourg. This shows that these pollutants are released under certain circumstances from old landfills and contaminated industrial sites (for ex. from scrap metal depots, transformer and capacitor factories, or plastic and metal industries) and constitute a hazard for the waters and the soil. As part of the management of contaminated sites, these punctual sources of pollution are inventoried and investigated and, if need be, remediated. To this date, twelve sites contaminated by PCBs have undergone remediation in Switzerland, for a total cost of about 25 million Swiss francs.

Contaminated sites

3. Reduce existing stocks in other countries and their transboundary spread. Furthermore, the developing countries must be supported in reducing their emissions of PCBs within the framework of the Stockholm Convention on persistent organic pollutants (POPs Convention).

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