Transfer and toxicokinetic modeling of non-dioxin-like polychlorinated biphenyls (ndl-PCBs) into accidentally exposed dairy cattle and their calves - A case report.

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that accumulate in tissues of exposed animals and humans. This case report refers ton=3 dairy cows accidentally exposed to non-dioxin-like PCBs (ndl-PCBs) of unknown origin on a German farm. At study start they had a cumulative total of 122-643 ng/g fat in milk and 105-591 ng/g fat in blood, consisting mainly of PCBs 138, 153, and 180. Two cows calved during the study and their calves were raised on their mothers' milk, resulting in cumulative exposure until slaughter. A physiologically based toxicokinetic model was developed to describe the fate of ndl-PCBs in the animals. The toxicokinetic behavior of ndl-PCBs was simulated in individual animals, including transfer of contaminants into calves via milk and placenta. Both the simulations and experimental data indicate that contamination via both routes is significant. In addition, the model was used to estimate kinetic parameters for risk assessment.

Cause and Effect Analysis between Influencing Factors Related to Environmental Conditions, Hunting and Handling Practices and the Initial Microbial Load of Game Carcasses.

Environmental, hunting and handling factors affect the microbial load of hunted game and the resulting meat products. The aim of this study was to systematically investigate the influence of several factors on the initial microbial load (IML) of game carcasses during the early hunting chain. Eviscerated roe deer body cavities (n = 24) were investigated in terms of total viable count and the levels of Pseudomonas spp., Lactobacillus spp., Enterobacteriaceae and Escherichia coli (E. coli). Furthermore, a risk analysis based on the obtained original IML data, literature search and a Failure Mode and Effects Analysis (FMEA) was performed. The IML could be explained in a regression model by factors including the higher body weight (BW), damaged gastrointestinal tract by the shot, ambient temperature or rain. The levels of Lactobacillus spp. (p = 0.0472), Enterobacteriaceae (p = 0.0070) and E. coli (p = 0.0015) were lower on the belly flap surface when gloves were used during evisceration. The literature search revealed that studies examining influencing factors (IF) on the IML of game carcasses found contradictory effects of the comparable IF on IML. Potential handling failures may lead to a higher IML of game carcasses during the early hunting chain ranked by FMEA. Several handling practices for game carcasses are recommended, such as ensuring efficient cooling of heavier BW carcasses to limit bacterial growth or eviscerating heavier carcasses before lighter ones.

Perfluoroalkylated substances in edible livers of farm animals, including depuration behaviour in young sheep fed with contaminated grass.

Perfluoroalkylated substances (PFASs) present a potential health risk for consumers. In animals these compounds are known to accumulate in livers. In order to determine potential PFASs contamination in commercially available livers, samples from farmed sheep, horses, cows, pigs and chicken were collected from the Dutch market. PFOS was the only detectable PFAS and its concentration was higher in free ranging animals like cows and sheep. The detected levels of PFOS in the liver samples were very low (up to 4.5 ng g(-1) ww). To further study the kinetic behaviour in foraging animals, samples from a study in which sheep were fed with grass obtained from a river floodplain, were examined. PFOS was the only detectable PFAS in the contaminated grass pellets, showing a level of about 0.5 µg kg(-1). Young blackhead sheep were fed with either clean or contaminated grass for a period up to 112 days. A time-dependent increase in liver PFOS concentrations was observed from 2.4 to 10.9 ng g(-1) ww after 8 and 112 days respectively. A time-dependent depuration was observed in livers of animals switched to clean grass after 56 days of exposure, from 9.2 to 4.7 ng g(-1) ww after 64 and 112 days respectively. The percentage of PFOS ingested from the grass and retained in the liver was estimated to be 12% at day 56, and decreased gradually to 6% after 56 days on clean grass, showing that the decrease in levels is not only caused by an increase in liver weight. Levels detected in commercial livers but also those in the sheep study would not lead to exceedance of the current TDI for PFOS set by EFSA. Therefore, it can be assumed that they do not present a risk for human health.

Accumulation of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in livers of young sheep.

A major part of sheep livers contains levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) above the former but to some extent also the new maximum levels (MLs) in the EU. In order to investigate the relationship between the intake of these contaminants and their accumulation in livers, kidney fat and meat, young blackhead sheep were fed with grass pellets containing PCDD/Fs at 2.5 times the maximum level. Levels of PCDD/Fs in livers were already quite high at the start of the exposure but increased 3-fold within 56d, exceeding the new product based MLs. Levels in meat and fat also increased but did not exceed the MLs. Although less elevated in the grass, both dl- and ndl-PCB levels also increased in liver and fat. Their kinetics in the tissues was less clear, potentially caused by increased levels in the straw given to the sheep during the whole experimental period. There was a clear difference in the behavior of the various congeners, the PCDFs and especially the higher chlorinated PCDFs and PCDDs showing a higher accumulation in the liver. In the case of the PCBs, this was particularly true for PCB 126. When switched to clean grass after 56d, the levels in livers and other tissues decreased to about the levels in the control sheep within 56d. This offers a potential solution for decreasing the intake of consumers.