Polychlorinated biphenyls (PCBs) are anthropogenic persistent organic pollutants (POPs) that are ubiquitous within the environment. Despite their worldwide ban in 2004 by the Stockholm Convention on POPs (chm.pops.int), up to 53% of the European citizens exceed the tolerable weekly PCB intake, with the ingestion of food of animal origin as the main exposure pathway. Only bovine meat and dairy products already contribute more than 70% to the total dietary PCB exposure. To reduce this exposure, authorities have set maximum regulatory levels in food, to which suckling cow herds have been shown to be occasionally non-compliant. Their exposure risk is enhanced by involuntary ingestion of soil (up to 10% of the total diet) while grazing, whereas suckling by the calves results in bioaccumulation. To ensure the chemical food safety and sustainability of grass-based suckling beef husbandries, it is mandatory to characterize the transgenerational fate of PCBs from diffusive grass and soil sources. Thus far, studies examining the PCB fate, including a detailed assessment of absorption, distribution, metabolism, and excretion (ADME) processes, in suckling cow-calf pairs are scarce, as it has primarily been described in dairy cows and non-lactating ewes. Additionally, studies have shown that physiological traits are important to consider, as these can influence the POP fate and obviously differ among dairy cows, suckling cows, and growing calves. The aims were (i) to characterize PCB congener-specific ADME kinetics in cows and calves when exposed via a diffusive soil source, and (ii) to quantify the PCB milk accumulation and decontamination toxicokinetics during full lactation.
