Occurrence, Fate and Determination of Tobacco (nicotine) and Alcohol (ethanol) Residues in Waste- and Environmental Waters

This review includes one hundred and two peer reviewed papers that focus on metabolic residues of the two most used licit drugs globally, nicotine (nicotine, cotinine, trans-3'-hydroxycotinine - HCOT) and alcohol (ethyl sulphate and ethyl glucuronide), in waste-and environmental waters. Sampling strategies and analytical methods are also summarised and discussed. Although grab sampling is the most widely applied method for collecting environmental samples (74% cases), wastewater samples are typically composite samples collected automatically at the wastewater treatment plants (66% cases). Sample preparation and analysis usually include solid-phase extraction (SPE) followed by reverse-phased liquid chromatography with tandem mass spectrometry detection (RP-LC-MS/MS) for nicotine residues. In contrast, alcohol residues are commonly determined via direct injection onto the LC-MS/MS using an ion-pair reagent to improve retention, leaving room for method improvement, e.g., introducing a suitable extraction procedure to achieve lower detection limits and quantifi-cation. In comparison to alcohol residues, more studies look into nicotine residues (85% of the studies). Con-centration ranges for nicotine, cotinine, HCOT and ethyl sulphate were < 424,000, < 42,300, 50-52,000 and 500-33,000 ng/L in wastewater influents and 15-32,000, < 18,000, 15-1,552 and < 500 ng/L in effluents, while nicotine (12.6-947 ng/L) and cotinine (17-62 ng/L) were detected in reclaimed waters. Among environmental waters, the highest concentrations of nicotine residues were measured in surface waters (nicotine: < 9,340 ng/L, cotinine: < 6,582 ng/L and HCOT: 14-777 ng/L), while their concentrations in groundwater and drinking water were generally in the low ng/L range. This review also reveals the discrepancy between the number of studies in developed countries (90%) compared to developing countries and the need for more studies in the former, where most wastewater flows untreated into the environment.