Occurrence of psychoactive stimulatory drugs in wastewaters in north-eastern Spain.

The occurrence of several psychoactive drugs in water resources from north-eastern Spain (NE-Spain) has been evaluated. The drugs were analyzed using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-ESI-MS/MS) after enrichment by solid-phase extraction (SPE). Most of the studied controlled drugs (8 out of 11) were found in both influent and effluent samples from several wastewater treatment plants. Cocaine and its metabolite were detected in wastewaters at concentrations ranging from 4 ng/L to 4.7 mug/L and from 9 ng/L to 7.5 mug/L respectively while concentrations of amphetamine type stimulatory drugs ranged from 2 to 688 ng/L. Removal percentages were estimated by sampling eight WWTPs (n=4). Cocaine and benzoylecgonine removal percentages were higher than 88% while those of amphetamine type stimulants varied ranging from 40% to more than 99%. Daily variability was also evaluated by performing a sequential survey, which revealed important fluctuations in the concentrations of nicotine, paraxanthine, amphetamine and ecstasy during the week. From the total concentrations found in wastewater influents estimations of the cocaine and ecstasy consumption were performed. For cocaine the results were approximately 14 doses per 1000 inhabitants (15-64 years old) per day and for ecstasy, approximately 4 doses per 1000 young adults (15-34 years old) per day for ecstasy.