The main source of dicofol in the environment is its use as a pesticide used on a wide variety of fruits, vegetables, ornamentals and field crops. A total amount of over 2700 tonnes of dicofol is used around the world each year, of which 290 tonnes is used in Western Europe. The only European countries which do allow its use are Belgium, Spain, Portugal and France. There are indications that through atmospheric transport, dicophol used in other continents might also end up in the North Sea. 
The degradation of dicofol in soil is moderately slow, with a half-life of 30 to 60 days. In water systems and soils with a high organic matter content, the half-life can reach 84 days. Like DDT, it also has a high affinity to lipids, which causes it to adsob to organic particles rather than dissolve in water. It's also highly bioaccumulative, and biomagnifying, therefore it poses a greater threat to high trophic level species such as birds and mammals.
Dicofol has been shown to be highly toxic for marine species. Fishes can die by chronic exposure to concentrations above 4,5 µg/l and concentrations above 12 µg/l can cause acute toxicity. In birds exposure to 20 mg of dicofol per kg body weight can cause eggshell thinning. It has also been shown to be a endocrine disrupting compound: male juvenile birds with a daily food intake of 5 mg dicofol per kg body weight showed effects of feminisation, which affected their mating behaviour and reproduction success.
Environmental standards and legislation