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Investigations of excretion and accumulation of non-dioxin-like polychlorinated biphenyls (ndl-PCB) in dairy cows
Project
Project code: BfR-SiN-08-1322-682
Contract period: 01.01.2017
- 31.12.2017
Purpose of research: Applied research
Polychlorinated biphenyls (PCB) are a group of 209 congeners. They differ in regard to their toxicological profile, whereas 12 of them share a structural similarity and toxic mode of action with dioxin (dioxin-like PCB, dl-PCB). All other PCBs do not show similarities with dioxin and are therefore called 'non-dioxin-like' PCB (ndl-PCB). In 2013 the International Agency for Research on Cancer classified all PCB together as carcinogenic to humans (Group 1). The fact that ndl-PCBs usually occur in presence of dioxins and dl-PCBs makes it difficult to characterize their toxicological profile independently. Therefore, no toxicological guidance value can be derived until now. Since 2012 and in accordance with the Commission Regulation (EU) No 1259/2011 the maximum admissible levels for ndl-PCB in beef, liver and milk is 40 ng/g fat. The maximus level refers to the sum of the six so call indicator-PCBs (PCB 28, 52, 101, 138, 153 and 180). The sum of them nearly represents the half of the existing ndl-PCB in food and feed and thus is considered as useful parameter to assess human exposure to ndl-PCB. The human exposition is mainly due to food intake, especially by the consumption of milk and milk products. Every day, low values of ndl-PCB are absorbed by the organism via food intake and stored in the fad depots and fatty organs. Therefore, even the continuous intake of low ndl-PCB levels are of high scientific interest and it has to be an aim of consumer protection to take care, that even in high age no critical body burden occurs. Like humans, dairy cows are exposed daily by low levels of ndl-PCBs via feed intake. The maximum admissible levels on undesirable substances in animal feed are regulated by the Commission Regulation (EU) No 277/2012. Compared to e.g. beef cattle, dairy cows have a higher life span and therefore they belong to a category of species more exposed to ndl-PCB. The excretion takes places primarily via milk. Some literature describes an elimination on two different stages, a lower second stage follows a fast first decrease of ndl-PCB concentration in milk. Unfortunately, data describing accumulation and elimination of ndl-PCB congeners are inconsistent and in many cases more than the six indicator-congeners were detected in scientific research. However to predict new knowledge on ndl-PCB regarding to the food chain on European level, detection of the named six indicator-ndl-PCBs allows a good comparability. The dairy cows of project (n = 3) came from a small farm in Lower Saxony, Germany. Increased values of ndl-PCB in the milk were detected in April 2016. The contamination pathway could not be clarified by date. Maybe a technical defect of the cooling technology caused the contamination of cow environment (feeding stuff, dust). Due to the high levels of ndl-PCB in milk even the meat was not approved for food chain. Furthermore, some cows of the herd were pregnant when contamination was detected first. On 25/07 and 09/08/2016 three cows of the herd were identified with ndl-PCB levels in milk in partly 10-fold higher than permitted (607 ng/g; 167 ng/g; 156 ng/g). On 02/09/2016 the BfR bought these three cows, which are housed at the experimental station of the BfR right now. Two cows where already pregnant at the arrival, the third cow was inseminated end of November. The present project belongs to the current and the following lactation. Ndl-PCB concentration in milk and bovine tissue will be analyzed by the National Reference Laboratory (NRL) for Dioxins and PCBs in Food and Feed at BfR. Therefore, to establish an appropriate method for the detection of ndl-PCB in milk is necessary first. Quantitative concentration of ndl-PCB in blood is planned to be analyzed by thirds. A corresponding awar to third-parties was prepared. All analysis relate to the detection of the 6 named indicator-ndl-PCB. A request of authorization for the animal experiment was submit on 02/11/2016 to Landesamt für Gesundheit und Soziales in Berlin.
Section overview
Subjects
- Animal Husbandry
- Food Chemistry
- Toxicology
