Assessment of estrogenicity bottled waters and its relation with the presence of endocrine disrupting compounds

As water is the fundamental requirement for living organisms to survive, the pollutants in water are amongst the most crucial aspects to be considered. Recently, contaminants in drinking water have become an important issue due to both. Increase in pollution of water sources, as well as the incomplete mineralization in chlorination process leading to disinfection by products. Natural (estrone and 17β-estradiol) and synthetic (17α-ethynylestradiol) hormones usually stand out among the endocrine disrupting compounds (EDCs) and these compounds can enter the water cycle through their use in hormone therapy or in birth control pills and subsequently, lead to problems in several organisms. In addition to the hormones, organic pesticides such as DDT or atrazine are included among the EDC. Moreover, compounds such as alkylphenols and bisphenol-A, which are used during the production of flame resistant compounds, surface active compounds, as well as polycarbonate and epoxy resins, are examples of EDC. The effect of endocrine disrupting compounds (EDCs) on the environment and human health is increasingly becoming an important focus for scientific research and communities in the world. EDCs are known for their ability to mimic hormones and disrupt action or pathways of natural hormones, thereby, affecting normal hormonal functions. The presence of endocrine disrupting compounds in drinking and especially bottled water has become a major concern worldwide since they negatively affect wildlife and humans. As a result, EDCs should be effectively treated to eliminate wastewater effluents as one of their sources upon discharge of wastewater effluents into surface waters, which then, can be a source of drinking water. Unfortunately, since the removal efficiency of EDCs that enter wastewater treatment systems is not very high, the most important pathway for the introduction of EDCs into the water cycle is the treated wastewater discharged from wastewater treatment plants. Nevertheless, since several pesticides are included among the EDCs, not only point sources but also diffuse sources might lead to the pollution of surface waters and groundwater with EDCs. When we think about the water cycle, it is inevitable that the EDCs that might be present in surface water and groundwater contaminate drinking water. The effects of EDCs on hormonal systems on the basis of only their chemical structure is not possible. Also the appearance of one of the EDCs is not enough to prove estrogenic activity. Nevertheless, at low concentrations, the combination of some endocrine disturbing compounds is an importent issue in ecotoxicology and can have harmful effects on wildlife and humans. EDCs may possibly have an interference in wildlife and the endocrine system of humans by: i) mimicing natural hormones ii) disrupting action, pathways and synthesis of natural hormones iii) antagonizing the effect of natural hormones or iv) disrupting the synthesis of specific hormone receptors. Bisphenol A has attracted considerable attention all over the world because of its wide usage. BPA is a synthetic industrial chemical which acts as a building block for polycarbonate materials. More than 2.000 million tons/year of BPA are used in the manufacturing of a wide variety of domestic products. It has been used in the production of epoxy resins, as a protective lining on the inside of metal-based food and beverage cans, polycarbonate plastics, baby bottles, household electronics e.t.c. BPA has been discharged directly or indirectly into the environment and this results in the contamination of water, soil and the atmosphere. Also, it leaches from baby bottles during hydrolysis of the polymer and lacquer-coated cans. Nonylphenol is classified as an endocrine disrupting compund which is capable of interfering with the hormonal system of some organisms. It is originally produced from the degradation of nonylphenol ethoxylates which are mostly used as industrial surfactants. Substantial quantities of nonylphenol ethoxylates reach sewage treatment works, where they biodegrade into several by-products such as nonylphenol. Due to its physio-chemical characteristics nonylphenol, easily accumulates in environmental compartments. Nonylphenol is often found in matrices such as sewage sludge, effluents from sewage treatment works, river water and sediments, soil and groundwater. Health Canada proposed classification of BPA as toxic to human health and the environment in April, 2008. In 2011, EC established a specific migration limit for BPA from food plastic of 600 ng/g and a tolerable daily intake (TDI) of 0.05 mg/kg body weight has been set by the European Food Safety Authority (2006). The United States Environmental Protection Agency (USEPA) has established 50 µg/kg per day based on the lowest observable adverse effect level of BPA. In 2011, Sweden announced the ban of BPA in cans containing food for children under the age of three. Turkey banned the usage of BPA in baby bottles and other PC items which are produced for babies on 10 June 2011. Because of the harmful effects of the degradation of products containing nonylphenol ethoxylates in the environment, the use and production of these compounds have been banned in EU countries and strictly monitored in many other countries including Canada and Japan. The purpose of this study was to find out the occururence of endocrine disrupting compounds in bottled waters. There is also evidence of polyethylene terephthalate (PET) and polycarbonate being a source of contamination and estrogenic activity in commercially available bottled waters. The examined compunds were Bisphenol A (BPA) and nonylphenol (NP). The presence of EDCs were investigated in bottled waters from different brands purchased from local markets. To examine estrogenic activity and the concentration of EDCs in bottled waters, the yeast estrogen screen (YES) and LC-MS/MS analytical methods were used. Because the expected concentration of EDCs in bottled water was in nanograms, samples needed to be highly concentrated. Samples were cleaned-up and preconcentrated by the solid-phase extraction (SPE) procedure using Oasis HLB cartridges. 1 L volume of samples extracted to 10 mL was used for bioassay (YES) and 1 mL of sample was used for liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). Extraction was carried out on 17 different water samples of randomly choosen brands. BPA occurrence in samples which were concentrated 50 times was between 1,8 - 117,7 ng/L. The presence of anti-estrogenic compounds and/or the estrogenic activity of unknown/unindentified contaminants lead to a difference in results between YES and LC-MS/MS. Additionally, glass corboy water from 2 differend brands sample of one brand which had been chlorinated was carried out and estrogenic activity was over the limit of detection. The result shows that estrogenic activity in drinking water can also be a result of an incomplete mineralisation step of chlorination. YES bioassay optimized and used with the aim of assessing potential estrogenic activity of bottled waters and its relation with the presence of endocrine disrupting compounds was performed (applied) for the first time in Turkey.