Nitazenes Discharged during Super Bowl and Mardi Gras Celebrations in New Orleans, USA

The ongoing polysubstance use crisis in the United States has recently been intensified by an increase in the use of nitazenes and nitazene-laced fentanyl. Despite the increasing trend in nitazene identifications reported by the National Forensic Laboratory Information System since 2019, reliance on conventional epidemiological approaches and logistical challenges often delay timely forensic reporting. We developed and validated an analytical method capable of nearly real-time quantification of several nitazenes in wastewater samples. Of a total of nine nitazene analogues, metonitazene was quantified most frequently (1.92–4.19 ng/L), followed by N-pyrrolidino etonitazene, isotonitazene, butonitazene, and etonitazene, during Super Bowl and Mardi Gras celebrations in New Orleans, Louisiana. Metonitazene and N-pyrrolidino etonitazene were discharged at average rates of 4.07 ± 1.99 and 0.48 ± 0.20 mg day–1 (1000 people)−1, respectively, during Super Bowl and Mardi Gras weeks in New Orleans. Interestingly, protonitazene and N-pyrrolidino protonitazene were discharged only after Mardi Gras at average rates of 8.90 ± 5.70 and 0.92 ± 0.08 mg day–1 (1000 people)−1, respectively. This is the first report of comprehensive quantification of nitazenes, including butonitazene, metonitazene, etonitazene, and isotonitazene, in municipal wastewater, highlighting their usage in the United States.