Health risk of exposure to Bisphenol A (BPA).

Bisphenol A (BPA) belongs to chemicals that are produced in large quantities worldwide. It is commonly used as monomer in polycarbonate synthesis, plasticizer in the production of epoxy resins, as well as an additive for the elimination of surfeit of hydrochloric acid during the polyvinyl chloride (PVC) production. BPA is not only used in the production of plastics intended to a direct contact with food, including plastic packaging and kitchenware, but also in inner coatings of cans and jar caps. There are various routes of human exposure to this substance such as oral, by inhalation and transdermal. The main sources of exposure to BPA include food packaging and dust, dental materials, healthcare equipment, thermal paper, toys and articles for children and infants. BPA is metabolized in the liver to form bisphenol A glucuronide and mostly in this form is excreted with urine. Due to its phenolic structure BPA has been shown to interact with estrogen receptors and to act as agonist or antagonist via estrogen receptor (ER) dependent signalling pathways. Therefore, BPA has been shown to play a role in the pathogenesis of several endocrine disorders including female and male infertility, precocious puberty, hormone dependent tumours such as breast and prostate cancer and several metabolic disorders including polycystic ovary syndrome (PCOS). Because of the constant, daily exposure and its tendency to bio-accumulation, BPA seems to require special attention such as biomonitoring. This observation should include clinical tests of BPA concentration in the urine, which is not only one of the best methods of evaluation of the exposure to this compound, but also the dependence of the daily intake of BPA and the risk of some endocrine disorders.