ASSESSING THE RISKS TO HUMAN HEALTH ASSOCIATED WITH EXPOSURE TO DIOXINS

Dioxins in the environment, with the exception of episodes of the rele ase of large quantities, are low-level delayed effect hazards. A major route of exposure to dioxins in man is via food and the human dietary data can be compared with the Tolerable Daily Intake (TDI), the latte r being derived from animal toxicity studies. The assessment of risk h as utilized the results of animal studies and human epidemiological da ta resulting from accidental exposure to higher levels of dioxins and furans together with studies of chemical workers. The United Kingdom a ssessment has included developmental and reproductive toxicity, immuno toxicity and carcinogenicity, These considerations have led to a TDI o f 10 pg kg bw/day equivalent to a total intake of 600 pg per day as 2, 3,7,8-TCDD (2,3,7,8-Tetrachlorodibenzodioxin) equivalents for a 60 kg adult. This figure is in agreement with similar estimates in Germany a nd Canada. This paper concludes with three specific issues, namely die t and breast feeding, a comparison of the TDI with the estimated dieta ry intake and possible carcinogenic activity of the TCDD.