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Polychlorinated biphenyls (PCBs) - as WHO TEQ

PCBs, Arochlor, Pyranol, Clophen

SPRI Emission Reporting Threshold
0.00001 Kg/yr Pollutant Emissions to Air
0.002 Kg/yr Pollutant Emissions to Water
0.002 Kg/yr Pollutant Emissions to Waste Water
0.0001 Kg/yr Pollutant Emissions to Land
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Under normal conditions, Polychlorinated biphenyls (PCBs) are found as colourless oily liquids or waxy solids. They are chemically very stable and unreactive, non-flammable and resistant to heat. PCBs tend to be "hydrophobic", so do not mix well with water. They do however dissolve readily in organic (carbon-containing) solvents.
What is it used for?
PCBs have a variety of uses: in electrical transformers; as heat exchange fluids in machinery; as additives to paints, plastics, rubbers and flame retardants; as lubricants or adhesives; in inks and dyes; and in insulative materials.
Where does it come from?
Releases of PCBs may occur during their manufacture and use in industry. Disposal of products containing PCBs or application of contaminated sewage sludge to soils may also release them to the environment. There are not thought to be any natural sources of PCBs to the environment.
How might it affect the environment?
PCBs are toxic to wildlife, particularly aquatic organisms. The effects observed include serious reproductive and developmental problems and damage to the immune system. PCBs bind strongly to soils and sediments. Significant seepage to groundwaters is unlikely, because of their insolubility in water. However, this may occur if organic solvents are simultaneously released and solutions of PCBs are carried further. PCBs may persist in the environment for significant periods of time and are classed as persistent organic pollutants (POPs). It is therefore possible that the presence of PCBs in the environment poses a long-term threat to wildlife on both a local and global scale.
How might exposure to it affect human health?
Polychlorinated Biphenyls (PCBs)-total as WHO TEQ Polychlorinated biphenyls can enter the body either by inhalation of air containing polychlorinated biphenyls, ingestion of contaminated food or water, or by dermal contact with polychlorinated biphenyls or products containing polychlorinated biphenyls. Inhalation of air containing polychlorinated biphenyls can cause irritation of the respiratory tract. Exposure to elevated levels of polychlorinated biphenyls can affect the immune system and may cause neurological effects such as learning difficulties. Exposure to high levels may also cause depression, fatigue, liver damage and skin reactions such as chloracne. Ingestion of polychlorinated biphenyls can cause gastrointestinal irritation and may lead to effects similar to those for inhalation. Dermal contact with high levels of polychlorinated biphenyls may lead to effects similar to those for inhalation and ingestion. Polychlorinated biphenyls can be transferred from the mother to the child during pregnancy if the mother has been exposed to polychlorinated biphenyls. Nursing infants can also be exposed to polychlorinated biphenyls from breast milk if the mother has been exposed to polychlorinated biphenyls. The International Agency for Research on Cancer has designated polychlorinated biphenyls as probable carcinogens. However, exposure to polychlorinated biphenyls at normal background levels is unlikely to have any adverse effect on human health.
What steps are being taken to limit the potential impacts?
PCBs are UK Red List pollutants, reflecting the concern about their harmful impacts on the environment and human health. Releases of PCBs are controlled through the UK Pollution, Prevention and Control (PPC) Regulations. European Directives regulating levels of PCBs include that which restricts the marketing and use of certain "dangerous" substances (76/769/EEC), which aims to completely phase out the use of PCBs by 2010; the Hazardous Waste Directive, which protects groundwaters (91/689/EEC); and the Directive concerned with incineration of wastes (2000/76/EC). At an international level, the use of PCBs is tightly controlled under the UNECE POPs protocol and proposed for elimination under the UNEP POPs Convention. They are also listed as substances for priority action under the Helsinki and OSPAR Conventions which protect the marine environments of the Baltic Sea and north-east Atlantic Ocean respectively.