Spatial and temporal variations in the occurrence of cocaine and benzoylecgonine in waste- and surface water from Belgium and removal during wastewater treatment
van Nuijs, Alexander L.N.
Faculty of Sciences. Biology
Faculty of Pharmaceutical, Biomedical and Veterinary Sciences. Pharmacy
Faculty of Medicine and Health Sciences
Water research / International Association on Water Pollution Research. - Oxford, 1967, currens
, p. 1341-1349
University of Antwerp
Estimates of cocaine consumption are currently resulting from population surveys, consumer interviews and crime statistics. A new approach (sewage epidemiology) based on the analysis of cocaine (COC) and its metabolite, benzoylecgonine (BE), in water samples was applied to 10 river sites and 30 wastewater treatment plants (WWTPs) in Belgium. Each river site was sampled twice, during the summer of 2007 and the winter of 20072008, while each WWTP was sampled on a Sunday and a Wednesday, during the summerautumn of 2007 and the winter of 20072008. This sampling strategy allowed for the evaluation of spatial and seasonal variations in the occurrence of COC and BE in waste- and surface water. WWTP Brussel-Noord was sampled for 19 consecutive days to evaluate daily and weekly variations in the presence of COC and BE in wastewater. For 7 WWTPs, influent and effluent water samples were collected to investigate the removal of COC and BE during the wastewater treatment process. Analysis of water samples was performed using solid-phase extraction and liquid chromatography coupled to tandem mass spectrometry. Measured concentrations were further converted into an amount of used cocaine, called cocaine equivalents, as previously described in the literature. Results showed no significant difference in cocaine use between the investigated seasons. A constant cocaine consumption was observed during the week (MondayFriday) with peaks during the weekend for WWTP Brussel-Noord. The COC/BE ratio in water samples was significantly higher during winter, most probably due to a slower hydrolysis of cocaine in low-temperature water. COC and BE were removed in the investigated WWTPs with a removal efficiency of >93%.