Dioxins and Polychlorinated Biphenyls in Food

Polychlorinated biphenyls (PCBs) and dioxins are long-lasting environmental contaminants. They are by-products of fires and some manufacturing processes. The main sources of dioxins in the diet are from meat, meat products, milk and dairy products. The health effects of dioxins and dioxin-like PCBs include carcinogenicity, immunotoxicity, reproductive and developmental effects.

The aim of the research Programme is to understand the pathways by which dioxins and PCBs enter food, the levels at which they occur, and the mechanisms by which they accumulate through the food chain. This information will help improve our communication of risks to consumers and food producers, and to identify effective and proportionate means of reducing these risks. This will enable the Agency to advise food producers on effective means of minimising the dioxin and PCB content of food available to consumers by animal husbandry measures, differential sourcing, refining and decontamination processes.

The Programme supports the Agency’s strategy on chemical safety of food with its particular commitment to the problem of dioxins. It contributes to the aims of ensuring that chemicals, if present in food, do not compromise food safety and of having appropriate and enforceable controls in place.

Dioxins are a group of closely related compounds, 17 of which are known to be extremely toxic to certain species of laboratory animals. They can cause a wide range of effects in animals, including cancer and effects on the immune and reproductive systems. Dioxins are not produced intentionally but are formed in small quantities during combustion processes and are by-products of certain chemical manufacturing processes. PCBs are another group of chemicals, a few of which exhibit a mechanism of toxicity similar to that of the toxic dioxins and are often referred to as being ‘dioxin-like’. Both dioxins and PCBs are persistent in the environment and bioaccumulate in the food chain.

To improve the Agency's knowledge on the occurrence and consumers exposure to these chemicals, this Programme will:

• develop an understanding of mechanisms by which dioxins and PCBs transfer through the environment and into the food chain;
• develop analytical methods to help improve both the efficiency and effectiveness of the food surveillance programme and compliance with limits; and
• identify ways to minimise contamination, exposure, or its effects.

The work Programme as a whole should enable the Food Standards Agency to assess and reduce the risk to consumers from dioxins and PCBs present in food, and inform the UK in international negotiations on setting appropriate controls on these contaminants.

Research to address contamination of food by dioxins and PCBs has been identified as a priority area by the FSA board.

PCBs and dioxins are long-lasting environmental contaminants. They are by-products of fires and some manufacturing processes. The manufacture and general use of PCBs stopped in the 1970's and their use is now banned. Dioxins and PCBs can be detected in all foods and food contributes 95% of all human exposure to these chemicals. The highest concentrations are in fatty foods such as liver and oily fish. The main sources of dioxins in the diet are from meat, meat products, milk and dairy products. The health effects of dioxins and dioxin-like PCBs include carcinogenicity, immunotoxicity, reproductive and developmental effects.

In 2001 the UK’s Committee on Toxicity recommended that the Tolerable Daily Intake (TDI) for dioxins and dioxin-like PCBs should be lowered from 10 picograms TEQ per kilogram of bodyweight per day to 2 picograms TEQ per kilogram of bodyweight per day. This is in line with recent recommendations by international and European expert committees. Based on 1997 diets, average daily intakes for the UK population are 1.8 picograms TEQ per kilogram of bodyweight. As much as 36% of UK adults, and most children, may exceed the TDI in their daily diet.

The EU has agreed proposals for maximum permitted limits for dioxins in certain foodstuffs, recommendations for an EU-wide monitoring Programme, and analytical and sampling protocols for enforcement of these limits. Further legislation would extend the range of foods covered, reduce the current limits for dioxins, and set new limits for PCBs is in prospect. The Agency will need robust data and methodologies to be able to respond authoritatively and effectively to these proposals.

Work has already begun under the FSA’s existing Programme C01 (research) to achieve the Agency's aim of assessing the risk to consumers from these contaminants and identifying effective and proportionate means of reducing these risks in this area. The Programme will build on existing work by initiating a range of research and survey projects following consultation with scientific experts and consumer groups. Their objectives will be:

• to develop analytical methods to improve both the efficiency and effectiveness of the food surveillance programme and compliance with limits. Particular consideration will be given to reducing the time and cost of analysis to facilitate compliance with, and effective enforcement of the limits; and
• to develop an understanding of mechanisms by which dioxins and PCBs transfer through the environment and into the food chain; and
• to Identify ways to minimise contamination, exposure, or its effects. The Agency will Identify and evaluate novel approaches to reducing dioxin levels in food to ensure continued reductions in the public’s dietary exposure to dioxins and dioxin like PCBs.

It is expected that this work will contribute to reductions in the public's dietary exposure to these contaminants. There may be opportunities within the Programme for co-funding of surveys and research with other government departments (e.g. DEFRA, DETR, EA, MAFF, DH) and other Member States (e.g. Ireland).

Name: David Mortimer
Tel: 020 7276 8731
Email: david.mortimer@foodstandards.gsi.gov.uk