engleski

Effect of water-matrix composition on photolytic degradation of sulfonamides metabolites

Today it is well established that source, presence and the fate of pharmaceuticals in the environment is of concern. Among different classes of pharmaceuticals, antibiotics are of the biggest concern since they can affect bacteria in the environment and thus disturb natural elemental cycles. Therefore, it is necessary to take a closer look at the fate and effects of these compounds in the environment. Sulfonamides represent one of the most commonly used families of antibiotics in human and veterinary medicine. Once in the body or animal, they are metabolized to more polar compounds that are more likely to pass through the wastewater treatment plants (WWTPs). As a result they are found together with their metabolites in WWTP effluents, surface, ground and drinking waters as well as in river, sediments and wastewater sludge. Once pharmaceuticals reach the environment many processes occur reducing their concentration. Photolysis, direct and indirect, might be an important elimination process for sulfonamides and their metabolites since they have aromatic rings, heteroatoms, and other functional chromophore groups that can absorb solar radiation. In direct photolysis pharmaceutical molecules absorb solar irradiation which causes the break-up of molecules, while indirect photolysis involves reaction with transient reactive intermediates such as singlet oxygen, hydroxyl radicals, or other reactive species formed in natural waters. N4-acetylated sulfonamides metabolites were irradiated under simulated sunlight in MilliQ, natural and synthetic wastewater similar by composition to wastewater of pharmaceutical industry in order to investigate influence of both direct and indirect photolysis. Beside these, influence of different water constituents (humic acids, chloride, nitrate, phosphate and sulfate ions) on their photolytic degradation was also studied. Furthermore, all experiments were conducted with both individual compounds and their mixture whereas they are present as mixture in the environment. Except the influence of the water-matrix composition on the photodegradation kinetics, the photodegradation products generated in water matrices were also identified by liquid chromatography-tandem mass spectrometry.

direct and indirect photolysis; sulfonamides metabolites

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