Dynamics of hexachlorobenzene residues in the food chain.

Epidemiological studies of food contamination in an area of intensive agriculture for the years 1975-1983 showed that hexachlorobenzene (HCB) was present in all food-chain links, although HCB has not been used in Czechoslovakian agriculture since 1980. Samples of potatoes, wheat, milk fat, eggs, meat and human milk were analysed by gas-liquid chromatography with electron-capture detector. Levels of HCB residues ranged from 0.02 (potatoes) to 2.5 mg/kg (human milk, fat basis). A study of HCB accumulation in eggs from a poultry experiment showed that HCB levels in eggs can reach about twice the level given in feed at 7-10 weeks.