They are entirely man-made and the biggest source in past years has been the incineration of municipal waste. In a report published last year the Inspectorate of Pollution (now part of the Environment Agency) stated that for breast-fed babies the estimated average intake of dioxins is approximately 9-28 picogrammes (pg) per kilogram body weight, per day, compared to the adult intake of 1-5pg.
These estimates were based on measurements by the Ministry of Agriculture and were used to demonstrate that the encouragement of incineration as a method of dealing with the UK's waste disposal problem would not cause any health hazards from dioxin emissions from the incinerator, as modern equipment could trap the dioxins and guarantee that less than 1,000pg of dioxins per cubic metre of air were discharged to air: this would mean that those living near the incinerator would only absorb a maximum of 0.1-0.5pg per Kgm body weight a day, a small amount compared with what they were absorbing from their diet.
The report however admits that even on their estimated figures breast- fed babies would be receiving more than the recommended daily dose.
Now we learn that actual measurements are far greater and show that breast- fed babies at two months old are absorbing as much as 110pg per Kgm in body weight plus another 60 pg of PCBs, of similar toxicity, which were not measured before. But, we are told, all will be well because once the baby goes on to mixed food and takes less milk the dioxins they have absorbed will gradually decay.
These compounds are accepted carcinogens; the Americans and many British scientists believe they are capable of affecting the hormones and the immune system. It is urgent that steps be taken to reduce the amounts in our diet as soon as possible. and the previous government's policy of encouraging incineration of municipal waste should be reversed. There are other ways of dealing with waste.
Dr PATRICIA ELLIOTT
Saffron Walden, Essex