Bisphenol A Is Released from Used Polycarbonate Animal Cages into Water at Room Temperature

Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA.
Environmental Health Perspectives (Impact Factor: 7.98). 08/2003; 111(9):1180-7. DOI: 10.1289/ehp.5993
Source: PubMed


Bisphenol A (BPA) is a monomer with estrogenic activity that is used in the production of food packaging, dental sealants, polycarbonate plastic, and many other products. The monomer has previously been reported to hydrolyze and leach from these products under high heat and alkaline conditions, and the amount of leaching increases as a function of use. We examined whether new and used polycarbonate animal cages passively release bioactive levels of BPA into water at room temperature and neutral pH. Purified water was incubated at room temperature in new polycarbonate and polysulfone cages and used (discolored) polycarbonate cages, as well as control (glass and used polypropylene) containers. The resulting water samples were characterized with gas chromatography/mass spectrometry (GC/MS) and tested for estrogenic activity using an MCF-7 human breast cancer cell proliferation assay. Significant estrogenic activity, identifiable as BPA by GC/MS (up to 310 micro g/L), was released from used polycarbonate animal cages. Detectable levels of BPA were released from new polycarbonate cages (up to 0.3 micro g/L) as well as new polysulfone cages (1.5 micro g/L), whereas no BPA was detected in water incubated in glass and used polypropylene cages. Finally, BPA exposure as a result of being housed in used polycarbonate cages produced a 16% increase in uterine weight in prepubertal female mice relative to females housed in used polypropylene cages, although the difference was not statistically significant. Our findings suggest that laboratory animals maintained in polycarbonate and polysulfone cages are exposed to BPA via leaching, with exposure reaching the highest levels in old cages.

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    • "Howdeshell et al. (2003) have shown that this compound becomes a problem once polycarbonate equipment is exposed to high temperatures and alkaline conditions, common procedures in sterilization and washing, and the amount of leaching increases as a function of use. Bisphenol A exposure as a result of being housed in used polycarbonate cages produced a 16% increase in uterine weight in prepubertal female mice relative to females housed in used polypropylene cages; however, it has to be noted that this difference was not statistically significant (Howdeshell et al. 2003). This should be taken as a warning sign; the animals in old cages with bottles or even complexity items made of polycarbonate may be exposed to varying amounts of Bisphenol A, which may interfere with any estrogen-sensitive parameters. "
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    • "Its release in the food chain is related mainly by sterilization process (temperature and time) and the amount of coating. As it is mentioned, BPA migrates from the coating of the can into the content mostly during the sterilization process (Howdeshell et al., 2003; Takao et al., 2002; Geens et al., 2010; Munguıa-Lopez et al., 2005). Duration of can storage, elevated temperatures during storage or damage of the can do not affect the levels of BPA in the food (Goodson et al., 2004). "
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