oral exposure to bisphenol a bpa used to seal canned food and beverage containers against bacterial contamination may not pose risk to humans, a new study has claimed.health concerns about bpa centre on its potential to mimic certain hormones at really high exposures.a 2013 study on dogs placed concentrated solutions of bpa under the tongues of sleeping beagles for an extended period.the amount of absorption and the amount of the active form of bpa measured in blood was higher than in previous studies in rodents, monkeys and humans.the authors hypothesised that this meant the amount of bpa in human blood could be higher than regulatory agencies assumed, an idea that became the basis for questioning the regulatory decisions."testing this hypothesis, in humans, became necessary," said toxicologist justin teeguarden of the us department of energy&39s pacific northwest national laboratory, author of the current study in humans.because the dog study challenged conclusions regarding bpa exposure in humans, teeguarden and his colleagues set out to determine if absorption of bpa from tissues of the mouth increased bpa blood levels in humans."our goal was to mimic normal eating behaviour, assuring that the results of the study would apply to humans eating and drinking," said teeguarden."this was something that was not possible in the dog study," said teeguarden.to fully coat the oral cavity, 10 male volunteers ate warmed tomato soup in which researchers had placed a traceable form of bpa. they took multiple blood and urine samples over a 24 hour period.the team found that coating the mouth in this way did not lead to higher levels of the active form of bpa in blood.as in all human studies to date, the body inactivated 998 out of every 1000 bpa molecules by the time bpa entered the bloodstream."just as important, we confirmed that there is no merit to hypotheses that bpa accumulates in humans. the entire dose of bpa was eliminated in urine within 24 hours, with no evidence of accumulation," said teeguarden.the study was published in the journal toxicology and applied pharmacology. 
