engleski

Abiotic elimination of febantel in the aquatic environment

There is now no doubt that a large number of pharmaceuticals are present in the environment. In contrast to noticeable amount of data about the presence, little is known about their fate in the aquatic environment. Once in the environment, pharmaceuticals are subjected to different elimination processes. These processes can be biotic (biodegradation by bacteria and fungi) and abiotic such as sorption, hydrolysis, photolysis, oxidation and reduction. The aim of this study was to examine abiotic elimination processes of febantel, anthelmintic drug with relatively high potential ecological risk. The objectives were to determine the hydrolysis and sunlight photolysis elimination constants and the sorption coefficients of the selected pharmaceutical by river sediments with different physico-chemical characteristics. Hydrolysis behavior was examined at pH and temperature values normally found in the environment. The results showed that febantel is hydrolytically unstable with half-lives in the range from 210 min to 99 days depending on pH and temperature values. The toxicity of mixture of febantel and hydrolytic degradation products were evaluated using Vibrio Fischeri. The results of direct and indirect photodegradation experiments suggest that febantel was persistent against simulated sunlight. The mechanism and kinetics of sorption, the impact of ionic strength and the influence of pH are examined. Experimental data showed the best agreement with the linear model (R2>0.99), while the rate of sorption is the best described with the kinetic model of pseudo- second-order.

febantel, environment, hydrolytic degradation, photodegradation, toxicity, sorption

nije evidentirano