Hexachlorobenzene (HCB), a banned persistent organic pollutant, was detected in milk products and meat after waste treatment in a cement plant in the Austrian valley Gӧrtschitztal. High concentrations in food led to a precautionary warning against the consumption of all food from the affected region. The dietary risk assessment revealed that the minimum risk level for human health for HCB, which is comparable to the usual tolerable daily intake value in Europe, of 0.07 μg/kg bw/d (Agency for Toxic Substances and Disease Registry) was exceeded at average and high consumption by all population groups up to 4-times and 8-times, respectively. Numerous public health related measures were taken and research activities started. HCB in meat and milk was strictly monitored in slaughterhouses and dairy farms, respectively. Meat and milk products containing HCB above the maximum residue levels were not placed on the market.
More than 5,000 t of contaminated feed was removed from the farms and substituted by HCB-free feedingstuff. Cows excrete HCB mainly via their milk which led to contamination of milk products and suckler calves. Farmers were advised to interrupt the on-farm cycle of HCB and to rehabilitate the farms and their products.
A human biomonitoring survey of the affected population revealed plasma concentrations of HCB in a broad range (0.1 to 5.29 μg/l blood plasma), which was well above the values of the reference group of 0.15 to 0.6 μg/l. Dietary recommendations were developed to facilitate the decrease of the internal HCB burden. Guidance levels for HCB in food for the affected population were calculated, that were significantly stricter than the maximum residue levels in EC regulations. The rather early detection of the HCB release and the risk management measures (stop of HCB emission, feed exchange, exchange of animals, etc.) led to a limited duration of increased uptake of HCB in the population. The public could be reassured that relevant health consequences would be unlikely.
