Analytical investigation of cannabis biomarkers in raw urban wastewater to refine consumption estimates

Marina Celia Campos-Mañas; Natan Van Wichelen; Adrian Covaci; Alexander L N van Nuijs; Christoph Ort; Frederic Béen; Sara Castiglioni; Félix Hernández; Lubertus Bijlsma

doi:10.1016/j.watres.2022.119020

Analytical investigation of cannabis biomarkers in raw urban wastewater to refine consumption estimates

Water Res. 2022 Sep 1:223:119020. doi: 10.1016/j.watres.2022.119020. Epub 2022 Aug 23.

Authors

Marina Celia Campos-Mañas¹, Natan Van Wichelen², Adrian Covaci², Alexander L N van Nuijs², Christoph Ort³, Frederic Béen⁴, Sara Castiglioni⁵, Félix Hernández¹, Lubertus Bijlsma⁶

Affiliations

¹ Environmental and Public Health Analytical Chemistry, Research Institute for Pesticides and Water (IUPA), University Jaume I, Castellón, Spain.
² Toxicological Centre, University of Antwerp, Antwerp, Belgium.
³ Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland.
⁴ KWR Water Research Institute, Nieuwegein, The Netherlands.
⁵ Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Department of Environmental Health Sciences, Milan, Italy.
⁶ Environmental and Public Health Analytical Chemistry, Research Institute for Pesticides and Water (IUPA), University Jaume I, Castellón, Spain. Electronic address: bijlsma@uji.es.

PMID: 36049245
DOI: 10.1016/j.watres.2022.119020

Abstract

Wastewater analysis of Δ⁹-tetrahydrocannabinol (THC) biomarkers can provide essential information on trends in cannabis consumption. Although analysis is mostly focused on the aqueous phase, previous studies have illustrated the need of improving the measurements of raw influent wastewater (IWW) considering also suspended solids. This is important for cannabis biomarkers, because a substantial part of them is expected to be found in the suspended solids due to their more lipophilic character compared with other metabolites/drugs included in these types of studies. However, it remains open to which extent trend estimates might be affected by solely analysing the liquid phase. To investigate this aspect, robust analytical methodologies are required to measure both the liquid and solid phases of IWW. In this work, we firstly tested liquid-liquid extraction (LLE) for THC and its major metabolites (THCOH, and THCCOOH). Using LLE, no filtration or centrifugation step was required for raw IWW analysis, and the three analytes were extracted from both the liquid and the solid phase simultaneously. In parallel, the raw IWW was centrifuged and the obtained solid and liquid phases were analyzed separately: the liquid phase by both LLE and solid phase extraction (SPE) for comparison of data, and the suspended solids by solid-liquid extraction (SLE). The separate analysis of both phases in a number of samples revealed that a significant amount of cannabis biomarkers (ranging from 42 to 90%) was found in the suspended solids. In addition, the total amount of cannabis biomarkers obtained by analysing raw IWW on the one hand, and by separate analysis of the liquid and the solid phases, on the other hand, was in good agreement. Data from this study show that the sole analysis of the liquid phase would lead to a notable underestimation of cannabis biomarkers concentrations in IWW.

Keywords: LC-MS/MS; Liquid-liquid extraction; Suspended solids; THC metabolites; Wastewater-based epidemiology; Δ(9)-tetrahydrocannabinol.

MeSH terms

Biomarkers
Cannabis* / metabolism
Dronabinol / analysis
Dronabinol / metabolism
Solid Phase Extraction / methods
Tandem Mass Spectrometry / methods
Wastewater* / analysis

Substances

Biomarkers
Waste Water
Dronabinol