Dioxins and polychlorinated biphenols (PCBs) are chemicals that get into our food from the environment. They have no immediate effect on our health but can cause problems if they are absorbed into our bodies at high levels for long periods.
Foods high in animal fat, such as milk, meat, fish and eggs (and foods produced with them) are the main source of dioxins and PCBs although all foods contains at least low levels of these chemicals. The levels of dioxins and PCBs in any one individual's diet will vary depending on the amounts and types of foods they eat.
The risk to health comes from eating food with high levels of dioxins and PCBs over a long period. They have been shown to cause a wide range of effects in certain animals, including cancer and damage to the immune and reproductive systems, although it appears that people may be less sensitive.
Where do dioxins and PCBs come from?Dioxins have never been produced intentionally. They may be formed as unwanted by-products in a variety of industrial and combustion processes, including household fires. Most industrial releases of dioxins are strictly controlled under pollution prevention and control regulations.
PCBs have been used since the early 1930s, mainly in electrical equipment. The manufacture and general use of PCBs stopped in the 1970s and is no longer permitted in the UK. The only PCBs remaining in use in the UK are sealed inside some older electrical equipment.
Dioxins and PCBs from these sources may be released in small quantities into the air, water or land. Animals and fish then take them up from their food and any soil and sediment they take in while they are feeding. The chemicals are absorbed into their body fat, where they accumulate.
Can I avoid eating food containing dioxins or PCBs?Because dioxins and PCBs are found at low levels in all foods, including foods that are important sources of nutrients, the Agency's advice is that the benefits of a healthy, balanced diet outweigh any risks from dioxins and PCBs.
There is very little scope for removal of dioxins and PCBs from foods once they have entered the food chain. It is generally agreed that the best method of preventing dioxins and PCBs from entering the food chain is to control releases of these chemicals to the environment.
The amount of dioxins and PCBs taken in by people in their food in the UK are similar to those in the rest of the European Union and USA. Intakes are falling and have reduced by 85% since 1982.
Is there a limit for the amount of dioxins in food?In July 2002, limits were set by the European Commission for dioxins in foods that contribute significantly to the total dietary intake of these chemicals. These foods include meat, liver, fish, eggs, milk and milk products. These limits are to be reviewed by December 2004.
A tolerable daily intake (TDI) is the amount of a contaminant that experts recommend can on average be eaten every day over a whole lifetime without causing harm.
What is the Agency doing about dioxins and PCBs?The Agency uses food and animal feed surveys to find out more about what foods make the highest contribution of dioxins and PCBs to the diet and to check that controls are adequate. It undertakes dietary surveys to monitor progress and to identify areas where more work is needed.
The Agency also carries out research to gain a better understanding of how dioxins and PCBs enter the food chain in the first place.