Seasonal and spatial distribution of caffeine, atrazine, atenolol and deet in surface and drinking waters from the brazilian federal district

Abstract

Selected emerging contaminants in water samples from the Brazilian capital were investigated by liquid chromatography-mass spectrometry after solid-phase extraction. In Paranoá Lake, an urban reservoir that will be used to produce drinking water, caffeine was the most abundant contaminant found (average of 53 ng L-1), followed by atenolol (34 ng L-1), N,N-diethyl-meta-toluamide (DEET, 12 ng L-1) and atrazine (3.8 ng L-1). The role of wastewaters discharges could not be evidenced probably due to the water flow and circulation in the lake. However, higher concentrations were detected during the dry season suggesting the presence of point sources, except for atrazine. In source waters, concentrations were lower in comparison with Paranoá Lake waters. Environmental risk assessment shows the need for further surveys for atrazine. For drinking waters, only caffeine and atrazine were detected at average concentrations of 8.6 and 3.2 ng L-1, respectively. No risk for human health was observed.