TBBPA is principally used as a reactive brominated flame retardant (BFR) in epoxy and polycarbonate resins, as well as an additive in acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS) and phenolic resins.
But the chemical is also found in the environment in fish and birds, and can enter the food chain as the result of releases at production sites, and, according to EFSA's Panel on Contaminants in the Food Chain (CONTAM), “probably more importantly via leakage from products where it has been introduced as an additive flame retardant”.
Following a call for data, after the European Commission (EC) requested it deliver a scientific opinion on TBBPA and its derivatives in 2010, EFSA said it received analytical results from 344 food samples submitted by EU member states Norway (70 per cent) and Spain (30 per cent) from 2007 to 2010.
Limited data set
Results submitted related only to one food group, ‘fish and other seafood’, and were all reported as being ‘<LOQ’ or below the limit of quantification, of approximately 1 nanogram (ng)/g by wet weight.
EFSA admitted there were imitations in the representative nature of this data, but did mention that Shi et al. 2009 assessed 48 Chinese total diet samples, and found the highest TBBPA levels in aquatic food groups, followed by meat products, with egg and egg products bringing up the rear.
Despite data limitations, the CONTAM panel said it assumed that occurrence levels of TBBPA in fish and other seafood in other EU countries would also not exceed the LOQ of 1ng/g.
Since, upon the basis of information submitted, a “meaningful exposure assessment for the general population [was] not possible,” the COTAM panel said it assessed ‘worst case’ intake estimates for adults with diets rich in fish.
Accordingly, the panel’s ‘upper bound’ intake estimate was 2.6 ng/kg of body weight per day, an “exposure scenario” that it said it did not believe raised cause for any health concerns.
Breast milk concentrations
The EFSA panel said that data on concentrations of TBBPA in human milk in Europe was also limited, to three studies, with concentrations of TBBPA therein ranging from 0.06 to 37.3 ng/g fat, with a median of 0.48 ng/g fat.
These showed that three-month old infants breast fed (on average) 800ml of milk per day, were exposed to 0.28 to 171 ng/kg bw of TBBPA; those on 1200ml, 0.41 ng/kg to 257ng/kg bw. Again, the panel decided that exposure via human milk did not raise a health concern.
Overall, the CONTAM panel decided that occurrence data submitted was not sufficient to conduct a reliable dietary exposure assessment for the general population, or specific population groups such as infants, children or vegetarians.
However, it added: “In view of the large MOEs (margins of exposure), the CONTAM Panel concluded that current dietary exposure to TBBPA in the European Union does not raise a health concern."
The EFSA panel said it had received no occurrence data for TBBPA derivatives, and said there was a need for relevant data on production rates, use, chemical characteristics, occurrence in food and toxicity.
The full EFSA scientific opinion on TBBPA can be read here.