Dataset of illicit drug consumption during and post COVID-19 through wastewater in a city of Chile.

The present dataset reports illicit drug consumption estimated through wastewater-based epidemiology (WBE) in San Pedro de la Paz, Biobío Region, Chile. We collected 24 hour flow proportional Influent wastewater samples at the city wastewater treatment plant (WWTP). Sampling during the COVID-19 period was conducted on twelve days between 9 and 29 August 2021. We collected 50 samples divided in two periods i) COVID-19 period (between 9 and 29 August 2021) and ii) Post-COVID-19 (5 September 2022 to 30 August 2023). Samples collected were preserved by adding Sodium metabisulfite (0.5 g/L), and samples were stored at -20 °C until further analysis. Target analytes included benzoylecgonine (cocaine metabolite), 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH, cannabis metabolite), amphetamine, and 3,4-methylenedioxymethamphetamine (MDMA). Sample preparation involved filtration, pH adjustment, and solid-phase extraction, followed by quantitative analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Quality assurance and quality control (QA/QC) followed the best-practice protocols of the Sewage CORe Group Europe (SCORE) network, including isotopically labelled internal standards, matrix-matched calibration, recovery and matrix-effect assessment, and batch-level blanks and continuing calibration verifications. We normalized concentrations using the daily influent flow and estimated population served by the wastewater treatment plant according to the 2024 Chilean CENSUS. Results are reported as milligrams per day per 1000 inhabitants (mg/day/1000 inhabitants), with values below the limit of quantification informed as "NA". We provide the dataset in an excel file containing collection date, location information, population data, and normalized consumption estimates for each target compound. Data are publicly available in the Mendeley Data repository (DOI: 10.17632/vgpr6b99vf.1) and can be reused for methodological comparisons, inter-study analyses, and secondary modeling applications in WBE.