Residues of Selected Anticonvulsive Drugs in Surface Waters of the Elbe River Basin (Czech Republic)

Anticonvulsants are pharmaceuticals used for epilepsy treatment, pain syndromes therapy and for various psychiatric indications. They enter the aquatic environment mainly through wastewater and were found to cause both biochemical and behavioral changes in aquatic biota. Because the consumption of anticonvulsive drugs is quite high, their monitoring in the aquatic environment is needed. The Elbe River basin is the fourth largest in Europe; the Elbe flows into the North Sea and therefore its contamination is of international importance. The aim of the present study was to determine the presence and concentrations of anticonvulsant pharmaceuticals (carbamazepine, lamotrigine and gabapentin) and their analogues (gabapentin-lactam) in water samples obtained from the Elbe River and its tributaries located in the Czech Republic, as well as to evaluate their correlations with flow rates. The results of this study show that the selected drugs are present in the surface water of the Elbe River in tens to hundreds of ng/L, with the highest measured concentrations for gabapentin. Our results also indicate that the further the sampling point from the Elbe spring is, the higher the concentrations of monitored pharmaceuticals are. Moreover, small tributaries are significantly more contaminated due to their low flow rates with the exceptions of streams flowing from preserved natural sites. The results of the monitoring highlight the importance of building wastewater treatment plants at the municipalities where they are still not present with focus on technology that would be able to decompose substances with negative removal efficiency.