A new study on “Accumulation of mineral oil saturated hydrocarbons (MOSH) in female Fischer 344 rats: Comparison with human data and consequences of risk assessment” was published online on October 1, 2016 in the peer-reviewed scientific journal Science of the Total Environment (FPF reported). The aim of the study was to understand the accumulation of mineral oil saturated hydrocarbons (MOSH) in experimental animals (female Fisher rats) after oral dosing at three different levels (40 mg MOSH/kg food, 400, and 4000). MOSH are common contaminants of recycled paperboard and have been found to migrate into food from food packaging at levels in the ppm range (FPF reported); they originate from the use of mineral oil-based printing inks in non-food grade paper applications (like newspapers). Chemically, MOSH are very similar to polyolefin saturated hydrocarbons (POSH), which are non-intentionally added substances prevalent in polyethylene and polypropylene food contact materials (FPF reported).
The study is authored by scientists from the Official Food Control Authority of the Canton of Zurich, Switzerland, Toxalim INRA Toulouse, France, and the Norwegian Institute of Public Health; two of the study’s co-authors, Koni Grob and Jean-Pierre Cravedi, are members of the European Food Safety Authority’s (EFSA) expert panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF).
In the study, dose-dependent tissue accumulation of MOSH was observed in rats via oral uptake in feed, and the authors observed large differences linked to the three different exposure levels. Based on this finding, they conclude that “tissue concentrations at low dose are underestimated if linearly extrapolated from experiments with high doses;” linear extrapolation from high to low doses is common practice in chemical risk assessments.
Further, the study compared tissue-specific accumulation in rats to human biomonitoring data from an earlier study (Barp et al. 2014, Biedermann et al. 2015), showing that human chronic exposure leads to differences in the distribution of MOSH (both in the chemical composition of MOSH, as well as levels in fatty tissue versus the liver): In human samples, MOSH levels were similar in adipose tissue, liver and spleen, while in rats large differences between specific tissue levels were observed. These differences are likely due to chronic exposure (humans) vs. subchronic exposure (animal study). This finding implies that human exposures are systematically underestimated, warranting a reevaluation of the current acceptable daily intake.
In their conclusions, the authors further state that “more attention should be paid to the composition of the hydrocarbons,” mentioning the German Federal Institute for Risk Assessment’s (BfR) MOSH evaluation that differentiates between molecular mass ranges (FPF reported).
Barp, L., et al. (2017). “Accumulation of mineral oil saturated hydrocarbons (MOSH) in female Fischer 344 rats: Comparison with human data and consequences of risk assessment.” Science of the Total Environment (published online October 1, 2016).
Barp, L., et al. (2014). “Mineral oil in human tissues, Part I: Concentrations and molecular mass distributions.” Food and Chemical Toxicology 72:312-321.
Biedermann, M., et al. (2015). “Mineral oil in human tissues, Part II: Characterization of the accumulated hydrocarbons by comprehensive two-dimensional gas chromatography.” Science of The Total Environment 506-507:644-655.