Elimination of dioxins in milk by dairy cows after the long-term intake of contaminated sugar beet pellets

ABSTRACT

Dried feed materials, such as sugar beet pellets, may be a source of high levels of PCDD/Fs. The studies followed up dioxin congener elimination from contaminated milk (5.02 ± 1.39 pg WHO PCDD/F-PCBs-TEQ g⁻¹ fat) up to 338 days after withdrawal of polluted feed ingredient (4.37 ± 0.25 ng PCDD/F/DL-PCBs-TEQ kg⁻¹ feed). The main objectives of the study were to estimate the length of the time needed to achieve an acceptable PCDD/F milk level as set by European Union law, to track the fate of the PCDD/F congeners, and to assess the potential risk for consumers associated with long-term consumption of contaminated milk. After approximately 200 days, the PCDD/F levels reached ML (2.5 pg WHO-TEQ g⁻¹ fat), then decreased to the action level after more than 300 days (1.75 pg WHO-TEQ g⁻¹ fat) for most of cows. The potential risk of PCDD/F/DL-PCBs intake was characterised by comparing the theoretically calculated weekly and monthly intakes with the toxicological reference values (TRVs). The dioxin intake for the average adult and high-milk consumers did not exceed half of any of the TRVs applied (TWI, PTMI). The consumption of milk by children in the amount recommended by nutritionists (500 ml day^–1) resulted in an exposure equal to 317% TWI and 275% PTMI.

GRAPHICAL ABSTRACT

KEYWORDS:

• Dioxins
• cow milk
• elimination
• dried feedstuffs
• exposure
• risk assessment

Acknowledgments

The authors thank the dairy farmer who permitted them to collect milk and feed samples from his farm over the one-year period. They appreciate the help of the District Veterinary Inspectorate of Kolbuszowa, Poland, in sample collection. The skilful sample preparation by the technical staff of the Department of Radiobiology of the National Veterinary Research Institute is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Veterinary Research Institute, Pulawy [research project number S/159, 2014–2015].