Using Monte Carlo simulation to assess variability and uncertainty of tobacco consumption in a city by sewage epidemiology

Abstract

ObjectiveTo use Monte Carlo simulation to assess the uncertainty and variability of tobacco consumption through wastewater analysis in a city.MethodsA total of 11 wastewater treatment plants (WWTPs) (serving 2.2 million people; approximately 83% of urban population in Dalian) were selected and sampled. By detection and quantification of principal metabolites of nicotine, cotinine (COT) and trans-3′-hydroxycotinine (OH-COT), in raw wastewater, back calculation of tobacco use in the population of WWTPs can be realised.ResultsCOT and OH-COT were detected in the entire set of samples with an average concentration of 2.33±0.30 and 2.76±0.91 µg/L, respectively. The mass load of absorbed NIC during the sampling period ranged from 0.25 to 4.22 mg/day/capita with an average of 1.92 mg/day/capita. Using these data, we estimated that smokers in the sampling area consumed an average of 14.6 cigarettes per day for active smoker. Uncertainty and variability analysis by Monte Carlo simulation were used to refine this estimate: the procedure concluded that smokers in Dalian smoked between 10 and 27 cigarettes per day. This estimate showed good agreement with estimates from epidemiological research.ConclusionsSewage-based epidemiology may be a useful additional tool for the large-scale monitoring of patterns of tobacco use. Probabilistic methods can be used to strengthen the reliability of estimated use generated from wastewater analysis.

Potential impact of the sewer system on the applicability of alcohol and tobacco biomarkers in wastewater‐based epidemiology

“…Therefore, the uncertainty caused by in‐sewer stability of Cot and HCot is considered acceptable for WBE studies because it is equal or less than those from chemical analysis and both biomarkers can be used to estimate consumption of tobacco in the population. This finding supported the selection of many studies to use Cot and HCot as biomarkers for tobacco consumption …”

Measuring spatial and temporal trends of nicotine and alcohol consumption in Australia using wastewater‐based epidemiology

“…The estimation and the associated uncertainty were computed using Monte Carlo simulations with different parameters (Supporting information, Table S2), similar to the practice in other related studies based on the established equation: (concentrations × wastewater volumes) × excretion rates ÷ catchment populations. Two major steps of the back‐estimation were included: (a) obtaining the average daily mass load (mg/day) of the metabolite by multiplying its measured concentration with the daily total wastewater volume; and (b) extrapolating to population‐normalized consumption (mg/day/1000 people) based on the mass load, average excretion rate (Supporting information, Table S2) and molecular‐weight ratio of the parent substance to its metabolite .…”

“…Both cotinine and trans‐3′‐hydroxycotinine were used to estimate nicotine consumption. The resulting estimate was used to estimate the equivalent number of cigarettes smoked based on an average of 0.9 ± 0.15 mg of nicotine per cigarette (Supporting information, Table S2). Daily consumption figures were estimated from log‐transformed data to account for skewness.…”

“…Nicotine absorption was estimated and cigarette consumption calculated based on the average absorption of nicotine from tobacco cigarettes . The approach has now been applied in Belgium, China, Czech and Slovak Republics, Portugal and Spain . Publications to date have concentrated mainly on European communities.…”

Increased levels of the oxidative stress biomarker 8-iso-prostaglandin F2α in wastewater associated with tobacco use

“…In WBE studies, tobacco use can be estimated by the analysis of two urinary metabolites of nicotine; cotinine and trans-3′-hydroxycotinine3233343536. While enzymatic deconjugation is necessary to quantify total cotinine in wastewater, there has been no significant difference observed between measurements made with and without the enzyme treatment for trans-3′-hydroxycotinine32.…”