Illicit drugs consumption evaluation by wastewater-based epidemiology in the urban area of Palermo city (Italy)

Introduction. A wastewater-based epidemiology approach was performed to estimate the drug consumption in Palermo city, the fifth largest city of Italy with a population of 671 696 inhabitants, and to investigate the monthly variability of drug loads in wastewater from different areas of the city. A seven-months detection campaign was conducted at the two wastewater treatment plants of the city. Methods. Following a pre-treatment, 32 samples of wastewater were analyzed by liquid chromatography-tandem mass spectrometry. Results. We estimated a mean cocaine use in Palermo of 0.19 g/day/1000 people, corresponding to 1.90 doses/1000 people and cannabinoids use of 2.85 g/day/1000 people, corresponding to 35.62 doses/1000 people. Amphetamines residues in wastewater were always recovered in concentrations lower than the limit of quantification. Conclusion. Our findings showed that drugs consumption in Palermo is in line with those of other Italian cities and that no significant differences on prevalence on cocaine and cannabinoids consumption were recorded in the different months of the survey, except for the summer period in a wastewater treatment plant of the city.