Transfer of Non-Dioxin-Like Polychlorinated Biphenyls (ndl-PCBs) from Feed and Soil into Hen Eggs

Abstract

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.

Toxicokinetic Modeling of the Transfer of Non-Dioxin-like Polychlorinated Biphenyls (ndl-PCBs) from Feed and Soil into Laying Hens and Their Eggs

“…For all individual congeners except PCB 28, the two experimental datasets from studies 1 and 2 , could be combined due to successful consensus (Table S5). Interestingly, the values of absorption from contaminated oil and paint particles F abs feed , though fitted independently, show almost identical values for all ndl-PCBs except for PCB 28.…”

“…In the first step, the controlled studies with contaminated feed (contamination from soil excluded) , (studies 1 and 2 in Table ) were used to optimize four parameters F abs feed , P CP , k eli , and k O .…”

“…During the second step, study 4 (refs , ) including contaminant transfer from both soil and feed into eggs was used to shed light on the transfer of ndl-PCBs from soil. The experiments in study 4 did not record the amount of soil consumed per laying hen.…”

“…The present TK models are based on multiple datasets for added confidence (Table ): the first dataset comes from our recent in-house study on ndl-PCB transfer into chicken eggs during a feeding experiment using controlled amounts of a commercial compound feed accidentally contaminated with paint from the loading cells of a feed company; a second dataset comes from controlled free-range husbandry on soils with predefined contamination levels simulating the soils from a highly urbanized area; , and the additional two datasets come from previous literature. , A typical question that our models can help risk managers to answer is: “How long should a depuration period using uncontaminated feed be so that the concentrations of ndl-PCBs in laying hen body fat and eggs drop below the maximum levels?” In addition to this, the models can help risk managers to establish ndl-PCB concentrations in soil and reconsider those in feed, so that they will not lead to exceedance of maximum levels in eggs . For the sake of transparency and reusability, the model described below is included in the Supporting Information in the Food Safety Knowledge Exchange .fskx and Python .py formats.…”

“…The present TK models are based on multiple datasets for added confidence (Table 1): the first dataset comes from our recent in-house study on ndl-PCB transfer into chicken eggs during a feeding experiment using controlled amounts of a commercial compound feed accidentally contaminated with paint from the loading cells of a feed company; 10 a second dataset comes from controlled free-range husbandry on soils with predefined contamination levels simulating the soils from a highly urbanized area; 10,11 and the additional two datasets come from previous literature. 12,13 A typical question that our models can help risk managers to answer is: "How long should a depuration period using uncontaminated feed be so that the concentrations of ndl-PCBs in laying hen body fat and eggs drop below the maximum levels?"…”