Using Monte Carlo simulation to assess uncertainty and variability of methamphetamine use and prevalence from wastewater analysis

Efficient magnetic solid-phase extraction, UPLC-MS/MS detection, and consumption assessment of five trace psychoactive substances

Wastewater-based epidemiology (WBE) has become an objective and updated surveillance strategy for monitoring and estimating consumption trends of psychoactive substances (PSs) in the population. Firstly, magnetic shrimp shell biochar-based adsorbent (DZMBC) was synthesized and employed for extraction trace PSs from municipal wastewater. Proper pyrolysis temperature and increased KOH activator content favored the pore structure and surface area, thus facilitating extraction. DZMBC delivered exceptional extraction performance such as pH stability, anti-interference property, fast magnetic separation ability, reusability, and reproducibility. Then, a method based on magnetic solid-phase extraction (MSPE) followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed, validated, and utilized for the quantitative determination of five PSs in real wastewater samples. Methodological validation results indicated a favorable linearity, low method limits of detection (1.00-4.75 ng/L), and good precisions (intra-day and inter-day relative standard deviations < 4.8%). Finally, an objective snapshot of Chongqing drug use and consumption pattern was obtained. Methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA) were the prevalent illegal drugs in local. Both concentrations and per capita consumption of MDMA displayed a change (P < 0.05) between July and September, while no statistical differences were observed for each week.

Simultaneous identification of groundwater pollution source and important hydrogeological parameters considering the noise uncertainty of observational data

Groundwater pollution identification is an inverse problem. When solving the inverse problem using regular methods such as simulation-optimization or stochastic statistical approaches, requires repeatedly calling the simulation model for forward calculations, which is a time-consuming process. Currently, the problem is often solved by building a surrogate model for the simulation model. However, the surrogate model is only an intermediate step in regular methods, such as the simulation-optimization method that also require the creation and solution of an optimization model with the minimum objective function, which adds complexity and time to the inversion task and presents an obstacle to achieving fast inversion. In the present study, the extreme gradient boosting (XGBoost) method and the back propagation neural network (BPNN) method were used to directly establish the mapping relationships between the output and input of the simulation model, which could directly obtain the inversion results of the variables to be identified (pollution sources release histories and hydraulic conductivities) based on actual observational data for fast inversion. In addition, to consider the uncertainty of observation data noise, the inversion accuracy of the two machine learning methods was compared, and the method with higher precision was selected for the uncertainty analysis. The results indicated that both the BPNN and XGBoost methods could perform inversion tasks well, with a mean absolute percentage error (MAPE) of 4.15% and 1.39%, respectively. Using the BPNN, with better accuracy for uncertainty analysis, when the maximum probabilistic density value was selected as the inversion result, the MAPE was 2.13%. We obtained the inversion results under different confidence levels and decision makers of groundwater pollution prevention and control can choose different inversion results according to their needs.

Application of the metal ions as potential population biomarkers for wastewater-based epidemiology: estimating tobacco consumption in Southern China

Wastewater-based epidemiology (WBE) is an objective approach for the estimation of population-level exposure to a wide range of substances, in which the use of a population biomarker (PB) could significantly reduce back-calculation errors. Although some endogenous or exogenous compounds such as cotinine and other hormones have been developed as PBs, more PBs still need to be identified and evaluated. This study aimed to propose a novel method to estimate population parameters from the mass load of metal ion biomarkers in wastewater, and estimate the consumption of tobacco in 24 cities in Southern China using the developed method. Daily wastewater samples were collected from 234 wastewater treatment plants (WWTPs) in 24 cities in Southern China. Atomic absorption spectroscopy (AAS) was applied to determine the concentrations of common health-related metal ions in wastewater, including sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), and zinc (Zn), and compared them with the daily mass load of cotinine corresponding to catchment populations. The concentrations of cotinine in wastewater samples were measured using liquid chromatography-tandem mass spectrometry. There were clear and strong correlations between the target metal ion equivalent population and census data. The correlation coefficients (R) were R_K = 0.78, R_Na = 0.66, R_Ca = 0.81, R_Mg = 0.77, and R_Fe = 0.69, at p < 0.01 and R² > 0.6. Subsequently, the combination of WBE and metal ion PBs was used to estimate tobacco consumption. Daily consumption of nicotine was estimated to be approximately 1.76 ± 1.19 mg/d/capita, equivalent to an average of 13.0 ± 8.75 cigarettes/d being consumed by smokers. The data on tobacco consumption in this study were consistent with those in traditional surveys in Southern China. The metal ion potassium is an appropriate PB for reflecting the real-time population and could be used to evaluate the tobacco consumption in WBE study.

Occurrence, spatial distribution, and potential risks of organic micropollutants in urban surface waters from qinghai, northwest China

Lack of knowledge on the destiny of organic micropollutants (OMPs) in the Tibetan Plateau region of China prevents the public from being aware of the need for protecting these unique aquatic ecosystems that are precious water resources and source areas of the Yellow River. To address this knowledge gap, this study systematically investigated the multi-residue analysis, distribution, and potential risks of six types of OMPs, namely, neonicotinoid pesticides (NEOs), fungicides, organophosphate esters (OPEs), organophosphorus pesticides (OPPs), psychoactive substances (PSs), and antidepressants (ADs), in surface waters of major cities in Qinghai. A total of 31 compounds, consisting of 8 NEOs, 1 fungicide, 12 OPEs, 2 OPPs, 5 PSs, and 3 ADs, were detected in >50% of the sites, showing their ubiquitous nature in the study area. Results showed that the total OMP concentration in surface water was 28.3-908 ng/L, and OPEs were the dominant composition (48.6%-97.4%). The risk quotient values of the detected diazinon and dursban regularly exceeded 1 for aquatic organisms at all sampling sites, indicating moderate-high chronic ecological risk. The joint probability curves showed that dursban and NEOs have higher risk levels than other OMPs. Although the results of the non-carcinogenic total hazard quotient of the OMPs in the surface water was less than 1 in all age groups and the carcinogenic risk was lower than the negligible risk level, the potential risks to children and infants were considerably greater and should not be underestimated. In addition to pollutant concentration and exposure duration, ingestion rate and body weight (BW) are also important factors affecting health risk, with BW having a negative effect. To the best of the authors' knowledge, this report is the first to describe OMP pollution in Qinghai, and the results provide new insight into the ecological security of the water resources of the Tibetan Plateau.

Identification and monitoring of fentanyls-related substances in east China sewage water samples by LC-MS for drug enforcement

Fentanyls abuse is a persistent international concern. New fentanyl derivatives are constantly appearing, circumventing national and international laws. In this study, laboratory degradation experiment with different conditions such as pH, light, temperature and oxygen availability were compared to improve the understanding of the fentanyls degradation pathways. Twelve major degradants of sufentanil and alfentanil were detected and identified together using UHPLC-QTOF-MS. A total of thirty nine fentanyls including twelve typical fentanyl new psychoactive substances, eighteen manufacturing process-related substances and nine key degradants of sufentanil and alfentanil were screened in 120 sewage water samples collected from 20 sewage water treatment plants chosen among 6 urban cities in east China from July to August in 2020 using a validated UHPLC-MS/MS method. Three fentanyls (fentanyl, sufentanil, alfentanil), seven degradants and six manufacturing process-related substances were found in the test samples. The study could provide a useful tool for the monitoring of the abuses, illegal manufacturing or pharmaceuticals related pollutions of fentanyls and their analogs.

Estimating dynamic population served by wastewater treatment plants using location-based services data

Wastewater-based epidemiology is a useful approach to estimate population-level exposure to a wide range of substances (e.g., drugs, chemicals, biological agents) by wastewater analysis. An important uncertainty in population normalized loads generated is related to the size and variability of the actual population served by wastewater treatment plants (WWTPs). Here, we built a population model using location-based services (LBS) data to estimate dynamic consumption of illicit drugs. First, the LBS data from Tencent Location Big Data and resident population were used to train a linear population model for estimating population (r² = 0.92). Then, the spatiotemporal accuracy of the population model was validated. In terms of temporal accuracy, we compared the model-based population with the time-aligned ammonia nitrogen (NH₄-N) population within the WWTP of SEG, showing a mean squared error of < 10%. In terms of spatial accuracy, we estimated the model-based population of 42 WWTPs in Dalian and compared it with the NH₄-N and design population, indicating good consistency overall (5% less than NH₄-N and 4% less than design). Furthermore, methamphetamine consumption and prevalence based on the model were calculated with an average of 111 mg/day/1000 inhabitants and 0.24%, respectively, and dynamically displayed on a visualization system for real-time monitoring. Our study provided a dynamic and accurate population for estimating the population-level use of illicit drugs, much improving the temporal and spatial trend analysis of drug use. Furthermore, accurate information on drug use could be used to assess population health risks in a community.

Wastewater analysis reveals urban, suburban, and rural spatial patterns of illicit drug use in Dalian, China

Illicit drug use in rural and suburban areas of China has not been studied extensively, as most studies have focused on illicit drug use in urban areas. To compare the differences between urban, suburban, and rural drug use, we collected influent samples from 19 urban, 9 suburban, and 18 rural wastewater treatment plants in Dalian, respectively. A method using solid-phase extraction combined with derivatization for gas chromatography -mass spectrometry analysis was applied to detect biomarker concentrations. The concentrations of methamphetamine and morphine ranged from 3.12 to 605 ng/L and < 2.35 to 198 ng/L, respectively. Norketamine was found in only four samples (5.56 to 14.5 ng/L), while 3,4-methylenedioxymethamphetamine and benzoylecgonine were not detected in any samples. Methamphetamine use in rural areas (16.3 mg/day/1000 inhabitant (inh), prevalence: 0.06%) was significantly lower than those in urban (77.1 mg/day/1000 inh, prevalence: 0.23%) and suburban (234 mg/day/1000 inh, prevalence: 0.70%) areas. Heroin use in suburban areas (57.6 mg/day/1000 inh, prevalence: 0.10%) was significantly higher than that in urban (13.9 mg/day/1000 inh, prevalence: 0.02%) and rural (8.68 mg/day/1000 inh, prevalence: 0.02%) areas. The results indicate relatively low levels of illicit drug use in rural areas of Dalian, related to low incomes and outflow of the working-age population. Illicit drug use was most prevalent in suburban areas of Dalian, which may be influenced by large floating populations and few anti-drug efforts in suburban areas.

Tracing consumption patterns of stimulants, opioids, and ketamine in China by wastewater-based epidemiology

Illicit drug use has long been a key issue of international concern, and the true situation is unknown to the relevant authorities. To develop a profile of comprehensive consumption patterns of illicit drugs in China, data from 34 wastewater treatment plants in 25 cities were collected to analyze four classes of drugs, including amphetamine-type stimulants, opioids, ketamine, and cocaine. They were identified and quantified in samples using methods based on gas chromatography coupled to mass spectrometry. According to the wastewater-based epidemiology (WBE) approach, an analysis of the consumption pattern was performed regarding per inhabitant consumption based on the revised metabolic rate. The consumption quantity of illicit drug and precursor was divided into four categories based on statistical difference analyses: methamphetamine and ephedrine (precursor) were the predominant drugs in the first category, followed by ketamine and heroin in the second category, methcathinone and 3,4-methylenedioxymethamphetamine (MDMA) in the third category, and cocaine and methadone in the fourth category. There were distinctive spatial patterns: heroin and cocaine consumption was higher in Southern China than in Northern China, heroin consumption was higher in Western China than in Eastern China, and the consumption of each drug differed across seven regions of China, especially with ephedrine and methcathinone consumption higher in North China; heroin consumption higher in Southwest, Central, and Northwest China; and ketamine and MDMA consumption higher in East, South, and Central China. Compared with findings in previous studies, there were temporal patterns, in which ketamine consumption presented a downward trend but heroin remained stable. Based on correlation analyses, there were the polydrug abuse patterns between heroin and cocaine, methcathinone and ketamine, and cocaine and MDMA. In general, this study based on WBE provides a comprehensive evaluation of drug consumption in China.

Application of multi-parameter population model based on endogenous population biomarkers and flow volume in wastewater epidemiology

The consumption or prevalence of acesulfame, caffeine, paracetamol and amantadine was estimated by wastewater-based epidemiology based on a multi-parameter population model in 20 sewage treatment plants (STPs) in Hebei province, China. To minimize the uncertainties contributed by population estimation in WBE, a multi-parameter population model was established based on the population biomarkers equivalent population and flow volume-population with the weight factors calculated by the analytic hierarchy process (AHP). 4-Pyridoxic acid (4-PA), cotinine, trans-3'-hydroxycotinine (trans-3'-OH-Cot) and 1,4-methylimidazole acetic acid (MIAA) were selected as population biomarkers. The estimated model population showed the highest correlations (r² = 0.97, p < 0.01) and lowest variation (one way-ANOVA, p = 0.82, mean variation: -0.1%) comparing to the census data, suggestion better population estimation. The estimated consumption of acesulfame, caffeine, paracetamol and amantadine was 6.7 ± 2.4 mg/day/inh, 50.5 ± 38.5 mg/day/inh, 61.5 ± 52.7 mg/day/inh and 0.52 ± 0.33 mg/day/inh, respectively. Meanwhile, the prevalence of paracetamol and amantadine was calculated to be 5.3% ± 4.5% and 0.28% ± 0.18%, respectively. The estimated results were consistent with that of previous researches in China and were also in accordance with the consumption calculated by sales data (acesulfame and paracetamol). Moreover, uncertainty study showed decrease in population-associated uncertainties by using a multi-parameter population model. The results demonstrated that the multi-parameter population model constructed in this research is feasible to apply in WBE and might lead to lower uncertainties in population estimation.

Estimating the prevalence of hepatitis B by wastewater-based epidemiology in 19 cities in China

China has the world's largest burden of Hepatitis B virus (HBV) infection, with 86 million HBV carriers, including 32 million chronic Hepatitis B patients. To monitor the HBV prevalence in near real-time, a wastewater-based epidemiology (WBE) method by using lamivudine as a biomarker was conducted in 19 cities in the Southern part of China. LC-MS/MS was utilized to quantify lamivudine in sewage, and satisfactory method validation results were achieved. The average concentration of lamivudine in sewage was 156.4 ± 107.1 ng/L, and the daily consumption was 30.1 ± 19.8 mg/day/1000inh in average ranging from 0.4 to 105.5 mg/day/1000inh. The prevalence of chronic Hepatitis B was estimated to be 2.5% ± 1.7% based on the prevalence of lamivudine usage, which was 0.035% ± 0.023%. Besides, the estimated HBV prevalence in population aged over 15 years in 19 cities was 6.8% ± 4.5% and was consistent with the previous statistical data of 7% in 2018. This research demonstrated that the estimation of HBV prevalence by WBE with lamivudine as a biomarker is feasible in big cities in Southern China.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

Methamphetamine use in typical Chinese cities evaluated by wastewater-based epidemiology

Methamphetamine has become one of the most widely used illicit drugs in China. To understand the current situation in China, the prevalence and consumption of methamphetamine were estimated through wastewater-based epidemiology (WBE) in the present study. Methamphetamine concentrations ranged from 42.6 ng/L (Harbin) to 700 ng/L (Xi'an) in influent wastewater samples collected from 27 wastewater treatment plants (WWTPs) in 22 Chinese cities. The estimated consumption of methamphetamine was 23.0 (Dingxi) to 376 (Xi'an) mg/day/1000 inhabitants with a mean value of 157 mg/day/1000 inhabitants. The annual consumption in 2018 was estimated to be 84 tons (95% confidence interval, 44-136), which was 26% lower than that in 2014. The prevalence of methamphetamine use was 0.64% (95% confidence interval, 0.18-1.25), indicating that more than five million people used methamphetamine in 2018. Although drug abuse is common in the country, the consumption showed a different spatial pattern, with the highest values in Central China and the lowest use in Northeast China, so drug use is still considered a geographic and culture-dependent behaviour. The results indicated that WBE can not only be used to assess the trends of illicit drug use, but also to analyse the spatial differences in the whole country, which will provide complementary evidence for the prevention and control of methamphetamine use.

Assessing the trend of diabetes mellitus by analyzing metformin as a biomarker in wastewater

According to International Diabetes Federation estimates, China has the highest rate of diabetes in the world. To monitor the prevalence of diabetes mellitus (DM) in near real-time, a first-line medication for the treatment of type 2 diabetes, metformin, was used. Wastewater-based epidemiology (WBE) was applied to estimate the consumption of metformin in Dalian from 2015 to 2018. Quantification of metformin was undertaken using solid-phase extraction (SPE) and N-methyl-bis (trifluoroacetamide) derivatization prior to GC-MS analysis. The concentrations of metformin in eleven wastewater treatment plants (WWTPs) ranged from 1.7 μg/L to 239.0 μg/L, with an average value of 68.3 μg/L. For metformin consumption, there was a gradual increase from 12.1 mg/d/capita in 2015 to 28.4 mg/d/capita in 2018. Meanwhile, the prevalence of metformin in the Dalian population ranged from 1.6% in 2015 to 3.8% in 2018. Similarly, the prevalence of DM showed an increasing trend from 12.2% in 2015 to 21.6% in 2018, which is consistent with the data predicted by traditional surveys (15.2-19.8%). Additionally, the prevalence of DM in 2015 estimated based on WBE was 12.2%, which agreed with the results from the traditional survey (12.3%). These results indicated that the proposed method provided a feasible way to reveal the prevalence of DM through metformin monitoring by the WBE approach.

Wastewater analysis reveals spatial pattern in consumption of anti-diabetes drug metformin in China

Metformin has been widely used as an oral drug for the treatment of diabetes mellitus. However, its consumption can be influenced by many economic and social factors. In this study, we investigated the spatial consumption pattern of metformin in China through wastewater-based epidemiology (WBE) approach. Influent wastewater samples were collected from 21 wastewater treatment plants (WWTPs) in 19 cities of the northeast China. A method using solid-phase extraction combined with N-Methyl-bis (trifluoroacetamide) derivatization for GC-MS detection was applied for metformin analysis. In 21 days, metformin showed high stability in wastewater at 24 °C and -20 °C. The mean concentrations of metformin in all WWTPs ranged from 2.42 μg L^-1 to 53.6 μg L^-1. The consumption of metformin was 0.66-15.6 mg d^-1 capita^-1 with the mean value of 5.54 ± 4.28 mg d^-1 capita^-1. The prevalence of metformin ranged from 0.09% to 2.10% with an average of 0.74%. Both the consumption and prevalence of metformin displays significant spatial variations in northeast China. A statistical correlation analysis indicated that the consumption of metformin increases with the decrease of per capita disposable income of urban residents. To further predict the use of metformin in China, we developed a regress model and depicted a consumption map. The annual consumption of urban residents in Chinese provinces range from 1085-63,828 kg yr^-1 with mean value of 25,347 kg yr^-1, which would provide a certain reference value for public health care and diabetes control.

Applying a population model based on hydrochemical parameters in wastewater-based epidemiology

Wastewater-based epidemiology combining with a population model based on hydrochemical parameters was applied in 10 wastewater treatment plants (WWTPs) in Jilin province, China. Population of WWTPs served was calculated by the model including three hydrochemical parameters ammonia nitrogen, chemical oxygen demand, and total phosphorus. The population model was constructed by using analytic hierarchy process to calculate weight factors of each hydrochemical parameters equivalent population. The size of population estimated by the model showed the highest correlations with cotinine mass load (r²=0.91, p<0.001), demonstrating better population estimation. Meanwhile daily excretion of cotinine per capita was first estimated about 0.68mg in China through liner regression analysis. In accessing the viability of the population model, the abuse of methamphetamine (METH) was calculated. Prevalence of METH use in Jilin province was calculated with an average of 0.72% based on the population model, which was similar with the result reported by United Nations World Drug Report in 2018. In assessing uncertainty of different population estimations, population model showed lower uncertainty than single hydrochemical equivalent population. These results indicate the population model based on hydrochemical parameters reduces uncertainty in population estimation and is a useful tool in monitoring illicit drug abuse.

Reduction in methamphetamine consumption trends from 2015 to 2018 detected by wastewater-based epidemiology in Dalian, China

BACKGROUND

Wastewater-based epidemiology (WBE) has become a useful tool in long-term or short-term continuous monitoring of illicit drugs consumption over the world.

METHODS

We investigated the trend of methamphetamine (METH) use between 2015 and 2018 through WBE in Dalian, a typical Chinese city. Samples were collected in 11 municipal wastewater treatment plants (WWTPs). An analytical method, solid-phase extraction combined with trifluoroacetic anhydride derivatization prior to gas chromatography-mass spectrometry (GC-MS) analysis was applied to detect METH concentrations.

RESULTS

During the sampling period, the METH concentrations increased slowly from 315 ± 243 ng/L in 2015 to 523 ± 549 ng/L in 2016, followed by a significant decrease with the concentrations 188 ± 187 ng/L in 2017 and 54.6 ± 42.9 ng/L in 2018. Ammonium nitrogen (NH₄-N) was applied to estimate population size. The average coefficient of variation for population in 11 WWTPs was 35.3 ± 8.9%, reflecting the dynamic variations of population effectively. For METH consumption, there was a gradual increase from 2015 (231 mg/day/1000 people) to 2016 (414 mg/day/1000 people) and a significant linear decrease to 2017 (206 mg/day/1000 people) and 2018 (53.9 mg/day/1000 people). The prevalence of METH increased from 2015 (0.78%) to 2016 (1.06%), then decreased to 2017 (0.55%) and 2018 (0.17%), showed similar trends with the consumption.

CONCLUSIONS

The obvious reduction trends of METH consumption via WBE over the period in Dalian provides objective evidence for declined METH consumption in local population. The reduction is probably due to the severe crack-down of illicit drugs by the government.