An article published on November 10, 2018, in the peer-reviewed journal Food and Chemical Toxicology, reported about toxic effects of dietary exposure to different fractions of mineral oil saturated hydrocarbons (MOSH). Unni Cecilie Nygaard and colleagues from the Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway, exposed female Fischer 344 rats through a “feed containing 0-400 mg/kg broad MOSH mixture for 30, 60, 90 and 120 days; and for 120 days to feed containing different MOSH fractions: I) mainly molecular masses < C25 (S-C25), II) dewaxed, mainly molecular masses > C25 (L-C25) and III) the L-C25 fraction mixed with wax largely consisting of n-alkanes > C25 (L-C25W).” The MOSH mixtures used for exposure as well as the accumulation in rat tissues have been characterized previously (FPF reported).
The scientists observed several treatment related effects including “increased liver and spleen weight, as well as vacuolization and granuloma formation with lymphoid cell clusters in liver.” These effects “varied strongly between the MOSH fractions tested.” The authors summarized that “increased liver and spleen weights were mainly related to accumulated iso-alkanes and substituted cycloalkanes, but also wax n-alkanes”; “induction of liver granuloma appeared to be related to [specific characteristics of] n-alkanes > C25 [such as molecular weight and melting point] and not to the accumulated amount of MOSH”; and “immune responses to an injected antigen were not affected.”
Further, the authors pointed out that “MOSH fractions associated with increased liver and spleen weights were similar to those accumulating in humans.” The increase in the liver weight “was not directly related to the accumulated amount of total MOSH in liver, but rather to specific chemical fractions.” Regarding the spleen, the authors emphasized that “MOSH concentrations reported in human spleens . . . are in the same range as those caused by the lowest dose of L-C25 in the present study, a dose which significantly increased the spleen weight.” The authors concluded that “the clinical significance of increased liver and spleen weights, which might occur in humans that are chronically exposed to MOSH, should be further investigated.”
Nygaard, U.C., et al. (2019). “Toxic effects of mineral oil saturated hydrocarbons (MOSH) and relation to accumulation in rat liver.” Food and Chemical Toxicology 123: 431-442.
Barp, L., et al. (2014). “Mineral oil in human tissues, Part I: Concentrations and molecular mass distributions.” Food and Chemical Toxicology 72: 312-321.
Barp, L., et al. (2017). “Accumulation of mineral oil saturated hydrocarbons (MOSH) in female Fischer 344 rats: Comparison with human data and consequences for risk assessment.” Science of the Total Environment 575: 1263-1278.
Barp, L., et al. (2017). “Mineral oil saturated hydrocarbons (MOSH) in female Fischer 344 rats: accumulation of wax components; implications for risk assessment.” Science of the Total Environment 583: 319-333.