Analysis of polychlorinated biphenyls (PCBs) in food
Polychlorinated biphenyls form a compound class of chlorinated aromatic hydrocarbons. There are 209 different PCB congeners, 130 of which are found in manufactured mixtures. There are dioxin-like (dl-PCBs) and non-dioxin-like PCBs (ndl-PCBs). The dioxin-like PCBs comprise 12 compounds (non-ortho PCBs and mono-ortho PCBs) whose molecular biological behaviour is similar to that of dioxins/furanes (PCDD/F). In early 2012 the EU also specified maximum levels for non-dioxin-like PCBs in food (indicator PCBs: PCB 28, 52, 101, 138, 153 and 180).
In ifp's laboratories the six indicator PCBs are detected by means of GC-MS/MS, after extraction from the sample.
How do PCBs get into the environment?
PCBs are not flammable, have high boiling points, high viscosity and are thermally and chemically stable. Due to these properties, they used to be applied in a large range of industries. From 1929 more than 1.2 million tons of PCBs were manufactured under trade names such as Aroclor (USA), Clophen (Germany), Fenchlor (Italy), or Phenochlor (France). These substances were used all over the world as cooling or insulating liquids, and as plasticisers or corrosion protection, for instance.
Only small quantities of PCBs were released directly into the environment. However, after their initial unlimited application and due to their chemical resistance, they gradually spread throughout the environment over the decades. PCBs have been found in water, soil, air, sediments, sewage sludge, plants and animals, indicating a certain degree of contamination almost everywhere today.
Legislation and risk assessment
The use of PCBs was heavily restricted by EC Directive 76/769/EEC of 1978 and the 10th Ordinance on the German Federal Immission Control Act (26 July 1978). The US banned the manufacture of PCBs in 1977, the Federeal Republic of Germany did not follow until 1983. Finally, since 1 January 1989 (Ordinance on Hazardous Substances) PCBs and products and devices containing PCBs may no longer be manufactured, imported, exported or sold in Germany. Due to these restrictions and bans, PCB pollution of the environment has already decreased. Yet major PCB quantities are still present in closed systems and devices, and in hazardous waste sites.
Regulation (EC) No. 1881/2006 regulates the maximum levels for the sum of dioxins, the sum of dioxin-like PCBs and the sum of the six marker or indicator PCBs (PCB 28, 52, 101, 138, 153 and 180) in food. The latter comprise about half of the amount of total ndl-PCBs present in food and feed.