OPINION OF THE SCIENTIFIC PANEL ON CONTAMINANTS IN THE FOOD CHAIN ON A REQUEST FROM THE COMMISSION RELATED TO HEXACHLOROBENZENE AS UNDESIRABLE SUBSTANCE IN ANIMAL FEED

Hexachlorobenzene (HCB) was introduced as an agricultural pesticide in 1945, and was banned in 1981 for agricultural use in the European Community. Nevertheless, it is still used to some extent as an industrial chemical and is still released to the environment during incineration and, to some extent, as a by-product from the manufacture of industrial chemicals and several pesticide formulations. HCB is quite volatile, highly lipophilic and among the more persistent environmental pollutants. As a result, it can be transported over long distances and is bioaccumulated in fatty tissues. HCB is ubiquitous in the environment, and is present in environmental and biological samples world-wide. HCB is included in the Stockholm convention on persistent organic pollutants (POPs)(1) and the United Nations Economic Commission for Europe (UNECE) Convention on long-range transboundary air pollution protocol on POPs (CLRTAP-POP)(2). In its evaluation of this contaminant, the CONTAM Panel examined occurrence data to assess the levels that are currently found in the environment and in food and feed. Fish derived products, particularly fish oils, were generally found to contain the highest levels of HCB. But high levels were also occasionally found in plant products such as pumpkin seeds as well as in vegetable oils from contaminated areas. HCB is readily absorbed in humans and animals. It has low acute toxicity. The liver is the predominant organ to be affected resulting in enzyme induction and porphyria. HCB is immunotoxic and causes ovarian toxicity in monkeys at a very low dose. Mink and Japanese quail seem to be among the most susceptible animal species. HCB is classified by IARC as a possible human carcinogen based on tumourigenic effects observed in experimental animals. HCB in some tests exhibits weak mutagenic activity and therefore a genotoxic mode of action could not be completely excluded. Despite its presence in the environment, and in many foodstuffs and animal feed, the data show a considerable decline of up to 90 % in human HCB exposure over the last twenty years. Recent dietary HCB intake for adults and children (breastfed infants excluded) ranges up to a few ng/kg body weight (b.w.) per day which is far below the suggested health based guidance value of 170 ng/kg b.w. per day. Furthermore, the margin between the dose causing liver tumours in rats and the human exposure range indicates low concern from a public health point of view.