Non-dioxin-like polychlorinated biphenyls (ndl-PCBs) are a subclass of persistent bioaccumulative pollutants able to enter the food chain. We investigated the transfer of ndl-PCBs from contaminated feed into meat and liver of fattening chickens. A total of 48 chicks were divided into five treatment and one control groups. Treated animals were fed with contaminated diets (11.7 ± 0.4 μg/kg sum of indicator ndl-PCBs; 88% dry matter (DM)) before slaughter for different subperiods of time: 16, 23, 28, 32, and 36 days for groups 1−5, respectively. One day after the end of each subperiod, three animals per group were slaughtered to determine the congener-specific ndl-PCB content. All remaining animals were fed the control feed until slaughter on day 37 to probe depuration. We used these data to generate congener-specific physiologically based toxicokinetic (PBTK) models for indicator ndl-PCBs. The models show that PCBs 28, 138, 153, and 180 form a more slowly eliminated cluster (with an observed transfer rate into meat over 74% and observed half-lives over 8.7 days) than PCBs 52 and 101 (with a transfer rate under 13% and half-lives under 2.6 days). Our simulations show that ndl-PCB levels in feed lower than 3.9 (long 56-day) or 4.4 μg/kg (short 37-day fattening period) would be necessary to ensure the current maximum level in muscle meat (fat basis), according to EU Regulations 1881/2006 and 1259/2011. The PBTK models are made available in the Python and Food Safety Knowledge Exchange formats.

Understanding the transfer of non-dioxin-like polychlorinated biphenyls (ndl-PCBs) into foods of animal origin is crucial for human health risk assessment. In two experiments, we investigated the transfer of ndl-PCBs from contaminated feed and soil into eggs and meat of laying hens. The transfer from the feed was investigated with 30 laying hens. The treated hens were divided into two groups fed a contaminated diet (12.8 μg/kg sum of indicator ndl-PCBs; 88% dry matter (DM)) for 28 and 63 days, respectively, and then experienced a depuration period of 100 days with control feed. The transfer from soil was investigated with 72 laying hens kept in three separate outdoor pens (with three levels of ndl-PCB soil contamination) for 168 days. In both experiments, eggs were collected and analyzed for ndl-PCBs. In the second experiment, animals (n = 3 at the beginning, n = 6 per group after 42, 84, and 168 days) were slaughtered to determine ndl-PCBs in meat (breast muscle tissue) fat. The transfer of ndl-PCB from both feed and soil was clearly measurable and concentrations in eggs quickly exceeded maximum levels. Clear differences between individual congeners were observed. In particular, the low-chlorinated ndl-PCBs 52 and 101 are hardly found in eggs, despite their relatively high concentration in feed and soil. PCBs 138, 153, and 180, on the other hand, were found in large proportions in eggs and meat.

Non-dioxin-like polychlorinated biphenyls (ndl-PCBs) are a subclass of persistent bioaccumulative pollutants able to enter the food chain. Toxicokinetic models for the transfer of the six ndl-PCB congeners (PCBs 28, 52, 101, 138, 153, and 180) from contaminated feed and soil into chicken eggs and meat are presented. Three independent controlled feeding study datasets were used to estimate the model parameters and four studies for evaluating the model performance. The yolk deposition of ndl-PCBs is modeled in a novel way that mimics the physiology of yolk growth and development, resulting in improved prediction of the experimental data without introducing an ad hoc time delay between ovulation and oviposition. Using the models, the highest level of 2.4 μg/kg dry matter (DM) was calculated for the sum of ndl-PCBs in laying hen feed to ensure that the current maximum levels in meat and eggs (40 ng/g fat) will not be exceeded. It is also shown how this highest level in feed should be adapted in case soil, in addition to feed, is also a source of ndl-PCBs for free-range chickens.