Polychlorinated biphenyls (PCBs) residues in commercial pasteurized cows' milk in Tehran, Iran

To date, despite the facts that pasteurized milk is the most consumed dairy product in Iran and its consumption has increased almost two fold during the last 10 years, no data are available concerning the concentrations of polychlorinated biphenyls (PCBs) in commercial cow milk in Iran market.

This study designed to determine the levels of PCBs in these products and to assess population exposure to PCBs by estimating the daily intakes. Pasteurized cows' milk samples (10 brands) were collected from local markets at two different seasons and analyzed using sensitive and reliable methods.

Based on the results all the indicator PCBs were detected and quantified in all of the samples, the mean ± SD concentration for the sum of the six congeners was 18.92 ± 14.36 ng g^-1 fat. None of the samples surpassed the provisional value established by the EU of 40 ng g^-1 fat. The sum of dioxin-like congeners, expressed as WHO-TEQ was 0.492 pg/g of fat which was considerably lower than the defined limit 3 pg/g fat, set for cow's milk. Furthermore, a similar DL-PCBs profile as other studies was found for analyzed samples. The results indicated that concentrations of DL-PCBs were very low, and all of milk samples were compliant with EC legislation. In addition, seasonal variations were not observed for DL- and NDL-PCBs levels (p values >0.05).

The estimated dietary intake for target population was 0.06 pg TEQ/kg of body weight/day, much smaller than the amounts declared by the World Health Organization as tolerable daily intake.