Occurrence and fate of illicit drugs and pharmaceuticals in wastewater from two wastewater treatment plants in Costa Rica Ana Causanilles a,b , Clemens Ruepert c , María Ibáñez d , Erik Emke a , Félix Hernández d , Pim de Voogt a,b, ⁎ a KWR Watercycle Research Institute, Chemical Water Quality and Health, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands b Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands c Central American Institute for Studies on Toxic Substances, Universidad Nacional, Heredia, Costa Rica d Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat s/n, E-12071 Castellón, Spain HIGHLIGHTS • Wastewater-based epidemiology first application in Central America • Key parameters assessment to apply best practice protocol • LC-HRMS analysis allowed target and suspect screening. • Cocaine and cannabis were found to be the most consumed drugs in Costa Rica. • Residues at low concentration were de- tected in surface water samples. GRAPHICAL ABSTRACT abstract article info Article history: Received 20 February 2017 Received in revised form 26 April 2017 Accepted 26 April 2017 Available online xxxx Editor: D. Barcelo Chemical analysis of raw wastewater in order to assess the presence of biological markers entering a wastewater treatment plant can provide objective information about the health and lifestyle of the population connected to the sewer system. This work was performed in a tropical country of Central America, Costa Rica, with the aim of extending this knowledge to new world regions. This work is the first to report wastewater-based epidemiolog- ical data on the use of illicit drugs in this region of the world. Composite wastewater samples from the influents of two different wastewater treatment facilities and surface water samples from surrounding areas were collected applying the best practice protocol and analysed to investigate the occurrence and fate of selected illicit drugs of abuse and pharmaceuticals. Results showed the presence of chemical indicators of the classic drugs cocaine and cannabis at high concentration levels, besides the moderate presence of the opiates codeine and morphine. Nei- ther the worldwide commonly used psychoactive substances of abuse such as synthetic phenethylamines, nor pharmaceuticals from the family of benzodiazepines were detected, demonstrating the spatial differences in drug use among different world regions. In addition, effluent wastewater samples were analysed and compared to influent concentrations in order to evaluate the decrease in concentration of the targeted analytes through two treatment technologies. As a final step, a wide-scope qualitative screening, including hundreds of suspect com- pounds, was applied in order to have a better knowledge on the presence of pharmaceuticals in waters and to assess the potential impact of the treated wastewater into the receiving aquatic ecosystems. © 2017 Published by Elsevier B.V. Keywords: Drugs of abuse Pharmaceuticals Wastewater High-resolution mass spectrometry Central America Tropics Science of the Total Environment 599–600 (2017) 98–107 ⁎ Corresponding author at: KWR Watercycle Research Institute, Chemical Water Quality and Health, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands. E-mail address: w.p.devoogt@uva.nl (P. de Voogt). http://dx.doi.org/10.1016/j.scitotenv.2017.04.202 0048-9697/© 2017 Published by Elsevier B.V. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv