Polychlorinated biphenyls (PCBs) were banned worldwide in 2004 due to their toxicity, persistency and bioaccumulation. However, human exposure to these persistent organic pollutants is still of concern since 50% Europeans exceed the tolerable weekly intake set by the World Health Organization, which was advised to be further reduced by a factor of seven by the European Food Safety Authority in 2018. As consumption of different kinds of meat accounts for ~30% of the total human exposure, chemical safety of meat must be ensured. For this, it is mandatory to understand and quantify PCB transfer from feed to adipose tissues of growing cattle producing meat, and how carcass lipid content and growing rate affect the biotransfer (BTF) and bioconcentration factor (BCF). Eleven bulls underwent a fattening period with feeds at PCB background levels. For PCB analyses, perineal adipose tissue was sampled at slaughter (530 (n=4) or 600 (n=7) kg body weight). The impact of carcass lipid content (estimated from the 11th rib dissection) and growing rate was tested by classifying the animals into low, medium or high carcass lipid content, or growing rate. For all PCBs tested, BTF and BCF decreased with increasing carcass lipid content - a typical dilution process. Conversely, growing rate had no effect. In addition, BTF and BCF increased with PCB chlorination degree. These results underpin how much the PCB transfer rates are influenced by the animal physiology and physicochemical properties, making it challenging to use average transfer factors for chemical risk assessment purposes.
