16/07/2010

Bisphenol A (BPA or 2,2-bis-(4-hidroxyphenil)propane) is a chemical which has been used for many years as a component in the manufacture of polycarbonate and epoxy-phenolic resins. Polycarbonate is a type of rigid, transparent plastic used in the manufacture of many food containers, such as re-usable drinks bottles, infant feeding bottles, dishes (plates and cups) and other containers. Epoxy-phenolic resins are used in coatings or linings for food and beverage cans and vats.

It is included on the list of monomers and other starting substances in Section A of Appendix II of Directive 2002/72/EC, with the reference number 13480, and it is also included on the list of additives fully harmonised at Community level in Section A of Annexe II of the same Directive according to which its use is authorised in Europe for the manufacture of plastic materials and objects for food applications.

As is the case with all food contact materials, small quantities of BPA can migrate from the plastic or the resin lining to foods and beverages. In this case, Directive 2002/72/EC sets a specific migration limit of 0.6 mg/Kg.

Bisphenol A is one of many substances which can potentially interact with human hormonal systems (endocrine disruptors). Its ability to mimic oestrogen (female sex hormone) has been known since the 1930s. There has been a great amount of scientific debate regarding its effects on fertility, reproduction and the endocrine system, linked to reports on the effects of low doses of BPA in rodents.

The European Food Safety Authority (EFSA) re-evaluated this substance in 2006 [1] in order to consider the new and extensive scientific information (over 200 publications) generated since its first evaluation in 2002 by the Scientific Committee on Food [2].

EFSA’s Scientific Panel considered that the effects from low doses in rodents had not been shown to be clear and reproducible, and could not therefore be used as reference studies in risk assessment. Furthermore, the differences between the species used in the toxicokinetic studies, such as the fact that parental BPA has a lower bioavailability in humans than in rodents, raise reasonable doubts as to the relevance for humans of any observation of low doses in rodents. The likely high sensitivity of mice to oestrogens raises further doubts as to the value of these particular species as a model for risk assessment of BPA in humans.

EFSA concluded that the tolerable daily intake (TDI) for the substance bisphenol A in humans should remain at 0.05 mg/kg/day, based on the results of a three-generation study in the rat (NOAEL = 5 mg/kg/day) and with an uncertainty factor of 100.

In calculating exposure EFSA took into account an adverse scenario with conservative migration levels, extreme consumption (95%) and different population groups including the most sensitive (babies of 3 months, babies of 6 months, children of 18 months and adults). The result shows a theoretical exposure that fluctuates between 0.2 and 13 ug/kg/day, representing a level of less than 30% of the tolerable daily intake.

The EFSA AFC Panel later published a new opinion on bisphenol A [3] in July 2008, this time with regard to the toxicokinetics of BPA, which considered that its previous risk assessment based on the overall NOAEL for effects in rats and using a default uncertainty factor of 100 can be considered as conservative for humans.

Finally, in September 2008, the European Commission asked EFSA for a new assessment following the publication of a study in the Journal of the American Medical Association (JAMA) which linked BPA levels in adult urine with health disorders. The authors concluded that higher urinary concentrations of BPA were associated with an increased prevalence of cardiovascular disease, diabetes and liver enzyme abnormalities.

Given the issue’s urgency, EFSA assessed this publication and published an opinion [4] on 22 October 2008 in which it concluded that the study in itself did not provide sufficient proof for a link between exposure to BPA and the health conditions mentioned above. Therefore, it considered that the TDI of 0.05 mg/kg/day should remain in place. It did not, however, rule out further assessments in the face of new toxicological information as it arises.

EFSA organised a meeting of national experts from the Member States on the 26 March 2010 to discuss EFSA’s ongoing scientific work on bisphenol A and to debate the draft opinion currently being prepared. EFSA gave the experts until 20 April to finalise the opinion.

Members of EFSA’s CEF Panel have been working on this opinion, taking into consideration over 800 studies, including an evaluation of the study regarding the possible neurotoxicity in rats (Stump 2009), but due to lack of time, the full opinion is not likely to be available until September, when the Panel is scheduled to meet in an extraordinary session.

However, in a letter to the European Commission, EFSA indicated that the TDI of 0.05 mg/kg/day would be maintained, although it suggested converting this into a temporary TDI. At the same time, the Panel identified areas of uncertainty which needed further consideration [5].

NOTE: This information is an update of that published on this website on 4 November 2008 and 14 April 2010.

 

[1] Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) related to 2,2-BIS(4-HYDROXYPHENYL)PROPANE. The EFSA Journal (2006) 428

[2] Opinión of the Scientific Committee on Food on Bisphenol A. SCF/CS/PM/3936 Final 3 May 2002

[3] Toxicokinetics of Bisphenol A - Scientific Opinion of the Panel on Food additives, Flavourings, Processing aids and Materials in Contact with Food (AFC).The EFSA Journal(2008) 759

[4] Statement of EFSA on a study associating bisphenol A with medical disorders – Prepared by the Unit on food contact materials, enzymes, flavourings and processing aids (CEF) and the Unit on Assessment Methodology (AMU).The EFSA Journal (2008) 838

[5] EFSA considers more than 800 studies on BPA, to finalise opinion in September