The Swedish Environmental Protection Agency hasundertaken a survey of current sources of persistentorganic pollutants, primarily dioxins, but also PCBsand hexachlorobenzene. The survey covers releases ofsuch substances from the metallurgical, cement, forestproducts and chemical industries, as well as from arange of combustion processes. Most of the dioxinsources known to us in the 1980s appear to havereduced their emissions, although in many casesrecent data are not available. Levels in theenvironment have also fallen, but this decrease isslowing down. More than 10% of Sweden's population are still exposed to levels of dioxins in their dietwhich exceed the highest tolerable daily intakedefined by the EU.The Agency considers the most important aim forsubsequent work in this area to be to obtain betterdata generally concerning the formation, release,dispersion and cycling of the groups of substances inquestion, so as to be better able to determine the scaleof the problems.