Evaluation of the Implications of Available Toxicology and Exposure Information for Tetrabromobisphenol A (TBBPA) for Risk Assessment

This review evaluated the mammalian toxicology of TBBPA and summarized available human exposure and risk assessments. The review noted that measured concentrations of TBBPA in house dust, human diet, and human serum samples are very low and that exposures of the general population are also well below the derived-no-effect-levels established for endpoints of potential concern under Europe’s chemical regulation law (Registration, Evaluation, Authorisation and Restriction of Chemicals, or REACH).1Source: Colnot, Thomas, Sam Kacew, and Wolfgang Dekant. “Mammalian toxicology and human exposures to the flame retardant 2, 2′, 6, 6′-tetrabromo-4, 4′-isopropylidenediphenol (TBBPA): implications for risk assessment.” Archives of Toxicology 88, no. 3 (2014): 553-573.

Key Takeaways:

  • The study demonstrated that TBBPA exerted no marked developmental effects at oral gavage doses of up to and including 1,000 mg/kg BW/day, the highest dose tested. 
  • The multigenerational study also was without any significant reproductive effects and was without all but one histopathological alteration at doses of ≤1,000 mg/kg BW/day. The sole histopathology lesion was thinning of the brain parietal cortex in F2 generation animals at PND 11 at the maternal oral dose of 1,000 mg/kg BW/day. This effect was not accompanied by any detectable neurodevelopment, neurofunctional or neurobehavioral deficits and needs to be interpreted with caution given the limitations of brain morphometric techniques used.
  • These findings are consistent with the observations of an extensive review of currently available TBBPA neurological data by Williams and DeSesso (2010) that demonstrated no adverse effects attributable to TBBPA exposures up to and including 1,000 mg/kg BW/day on neurodevelopment, neuromotor functions, learning, memory, and neurobehavioral endpoints.
  • A comprehensive National Toxicology Program investigation on the effects of TBBPA was conducted. In agreement with the Cope et al 2015 findings there were no treatment-related histopathological lesions and no marked changes reported in TSH and T3 levels.