engleski

Occurrence and behavior of antimicrobials in wastewaters and ambient waters in Croatia

Antimicrobials represent one of the most prominent classes of emerging contaminants. The main sources of these compounds in the environment are municipal and industrial wastewaters. Generally, current design of the conventional wastewater treatment plants (WWTPs) does not assure an efficient removal of refractory micropollutants, including some representatives of antimicrobials. Moreover, despite significant improvements in wastewater management during the last few years, vast majority of the Croatian wastewaters are still released in the environment without any treatment or after being treated only mechanically [1]. As a consequence, a large percentage of different classes of wastewater contaminants reach ambient waters in significant concentrations [2]. In this work we present the main results of a comprehensive study on the occurrence and fate of antimicrobials in Croatia during the period 2004- 2009. The study included a nation-wide survey of antimicrobials in wastewaters from all major Croatian cities and in some larger rivers. In addition, detailed studies of the behaviour and fate of antimicrobials, including diurnal and weekly dynamics and removal efficiencies in wastewater treatment as were performed in the full-scale mechanical-biological WWTPs in Cakovec and Zagreb. Samples were analyzed for the three important classes of antimicrobials, sulfonamides (together with trimethoprim), fluoroquinolones and macrolides, using a multiresidue method based on liquid chromatography – tandem mass spectrometry [3]. The application of the method showed a widespread occurrence of the investigated antimicrobials in Croatian municipal wastewaters with concentrations ranging from tens of ng/L to a few µg/L. Their removal during wastewater treatment was incomplete, with different elimination patterns for different antimicrobial classes, depending on the contribution of biological and physico-chemical processes in both dissolved and particulate phase. Traces of antimicrobials were also detected in river water samples, while occasional high concentrations of some macrolide antibiotics in the Sava River indicated wastewaters from pharmaceutical industry as an important input into the ambient waters.

antimicrobials; wastewater; ambient water; liquid chromatography- tandem mass spectrometry

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