Occurrence of contaminants of emerging concern in surface waters from Paraopeba River Basin in Brazil: seasonal changes and risk assessment.

This study describes the application of gas chromatography coupled to mass spectrometry (GC-MS) to evaluate the occurrence of 12 CECs-contaminants of emerging concern (bisphenol A, diclofenac, 17β-estradiol, estriol, estrone, 17α-ethinylestradiol, gemfibrozil, ibuprofen, naproxen, 4-nonylphenol, 4-octylphenol, and acetaminophen) in surface waters from Paraopeba River Basin, Minas Gerais State, Brazil. The analytical procedure was validated and applied to 60 surface water samples collected across four sampling campaigns along the upper and middle watershed. Methods for CECs determination involved sample filtration, and solid-phase extraction (SPE) with subsequent derivatization of the target compounds prior to their analysis by GC-MS.