Assessing Cocaine Use Patterns in the Brazilian Capital by Wastewater-Based Epidemiology

ABSTRACTThe levels of cocaine (COC) and its metabolites benzoylecgonine (BE) and cocaethylene (COE) in wastewater samples from Brasilia, Brazil, were determined using liquid chromatography coupled to hybrid quadrupole-time-of-flight mass spectrometry. The former metabolite was used to estimate cocaine consumption using a country-tuned correction factor that considers BE excretion rates for different routes of administration as well as the fraction of crack users in Brazil. A day-to-day analysis during a week indicates higher cocaine use in weekends with peaks on Sunday in both southern (7385 ± 121 mg day−1 1000 inhab−1) and northern (3566 ± 171 mg day−1 1000 inhab−1) areas of Brasilia. A significant high cocaine use was also observed in the Carnival Day of 2018 (6229 ± 219 mg day−1 1000 inhab−1). COE/BE ratios were used to assess COC and alcohol co-consumption since COE is produced during the co-consumption of both substances. Higher ratios were also observed during the weekend. However, higher ratios on ...