Determination of endocrine-disrupting compounds in waters from Rio das Velhas, Brazil, by liquid chromatography/high resolution mass spectrometry (ESI-LC-IT-TOF/MS)

Some organic microcontaminants, known as endocrine-disrupting compounds (EDC), are frequently found in surface waters and are of concern because of their ability to alter the normal functioning of the endocrine system. In this study five of these EDCs (estradiol, ethynylestradiol, bisphenol A, nonylphenol and diethylphthalate) in surface water samples, collected at the upper part of Rio das Velhas river (located between Ouro Preto and Nova Lima, Minas Gerais state, Brazil) were analysed. The analytical methodology, which employed solid-phase extraction and high-performance liquid chromatography coupled to high resolution mass spectrometry (HPLC-MS/MS), was properly validated and resulted in limits of quantification (LOQ, S/N = 10) of 4.3 ng/L for diethylphtalate, 3.9 ng/L for nonylphenol, 3.6 ng/L for estradiol, 4.7 ng/L for ethynylestradiol and 2.5 ng/L for bisphenol. The five compounds were monitored for eight months, from sites where the hormones were occasionally found. Ethynylestradiol and estradiol concentrations varied from 5.6 to 63.8 ng/L. Bisphenol was present in all samples in a concentration that ranged from 8.6 to 168.3 ng/L. The other two compounds were at quantifiable levels in all collected samples, with nonylphenol varying from 25.9 to 1435.3 ng/L and diethylphthalate from 5.0 to 410.9 ng/L. The study showed that nonylphenol pollution seemed to originate from agricultural run-off, while diethylphthalate pollution originated from the discharge of domestic sewage. Risk analysis studies showed that the environmental concentrations of nonylphenol and diethylphthalate do not present risks to human health; however, the concentrations found for bisphenol and ethinylestradiol could be toxic to humans, especially infants, if such compounds are not effectively removed at water treatment plants.