What is bisphenol?
Bisphenol, although it would be more correct to speak of bisphenols, is a compound that is obtained by acid or alkaline condensation of two phenol molecules with an aldehyde or ketone molecule. By esterification of bisphenol with diphenylcarbonate (or by condensation with phosgene) thermoplastic polycarbonates are obtained; some types of disphenol are used as stabilizers of monomers or polymers such as resins and cauciù. Chlorinated bisphenol is used as a fungicide and / or disinfectant.
Bisphenol A
Bisphenol A - C 15 H 16 O 2 : bisphenol A is obtained by the condensation of two phenol molecules; BPA or also known as 2-2 bis (4-hydroxyphenyl) propane, bisphenol A is a fundamental compound in the production of plastics and additives, and is one of the main monomers in polycarbonate synthesis.
Applications of bisphenol A
The applications of bisphenol A are large and widespread; although it has been partially withdrawn from the market, bisphenol A is still widely used in the production of fairly widespread domestic and foreign articles. It is not uncommon for its derivatives such as polycarbonate to unintentionally become part of the objects we use daily; the classification of the plastics varies from 1 to 7 and the bisphenol A is contained both in the products marked by the number 3 and by those marked with the number 7.
In particular, the polycarbonate obtained with bisphenol A has excellent physical characteristics (especially hardness); it is very resistant, therefore it is used for the production of: toys, bottles, sports equipment, medical and dental devices, glasses lenses, optical supports, household appliances, protective helmets and dental fillings .
That's not all, bisphenol A-based epoxy resins are an excellent internal coating of cans used as food and beverage containers.
Note how ALL the above products can easily be ingested; in addition to the inner coating of the cans, the plastic bottles and the dental features, bisphenol A constitutes a large part of the raw materials used in the production of children's toys.
Toxicity
Almost a century ago, bisphenol A was suspected of seriously damaging the health of consumers, but only in 2008 these findings were emphasized and disclosed by the competent institutions; at this point, many of the bisphenol A producers and sellers have been "induced" to block their trade.
Specifically, it appears that bisphenol A has affinity for the receptors of some steroid hormones (estrogens) and is responsible for the impairment of neural development. Not only that, bisphenol A is involved in the alteration of the sexual development of the male fetus, in the reduction of human fertility, in the complications of the breast and in those affecting the prostate. In females, bisphenol A also interferes with cardiac receptors, determining the release of calcium from the sarcoplasmic reticulum with relative cardiac arrhythmia.
According to studies conducted in 2008, the administration of bisphenol A determines different endocrine effects that allow to define a very low maximum daily dose (TDI) of 0.05 mg / kg. However, remaining below this threshold and even considering possible potentially risky conditions such as pregnancy, also thanks to the speed of metabolic disposal of this molecule, there is no reason to believe that the use of bisphenol A for plastic and for coatings may seriously harm the health of consumers.
Although it is a moderately toxic molecule it would be advisable to limit its contact and absolutely avoid even accidental ingestion.
Bibliography :
- New dictionary of applied commodity and chemistry . Volume 2 - V. Villavecchia, G. Eigenmann - Hoepli - pag 638
