Monitoring consumption of methadone and heroin in major Chinese cities by wastewater-based epidemiology

Exposure to environmental pollutants: A mini-review on the application of wastewater-based epidemiology approach

Wastewater-based epidemiology (WBE) is considered an innovative and promising tool for estimating community exposure to a wide range of chemical and biological compounds by analyzing wastewater. Despite scholars' interest in WBE studies, there are uncertainties and limitations associated with this approach. This current review focuses on the feasibility of the WBE approach in assessing environmental pollutants, including pesticides, heavy metals, phthalates, bisphenols, and personal care products (PCPs). Limitations and challenges of WBE studies are initially discussed, and then future perspectives, gaps, and recommendations are presented in this review. One of the key limitations of this approach is the selection and identification of appropriate biomarkers in studies. Selecting biomarkers considering the basic requirements of a human exposure biomarker is the most important criterion for validating this new approach. Assessing the stability of biomarkers in wastewater is crucial for reliable comparisons of substance consumption in the population. However, directly analyzing wastewater does not provide a clear picture of biomarker stability. This uncertainty affects the reliability of temporal and spatial comparisons. Various uncertainties also arise from different steps involved in WBE. These uncertainties include sewage sampling, exogenous sources, analytical measurements, back-calculation, and estimation of the population under investigation. Further research is necessary to ensure that measured pollutant levels accurately reflect human excretion. Utilizing data from WBE can support healthcare policy in assessing exposure to environmental pollutants in the general population. Moreover, WBE seems to be a valuable tool for biomarkers that indicate healthy conditions, lifestyle, disease identification, and exposure to pollutants. Although this approach has the potential to serve as a biomonitoring tool in large communities, it is necessary to monitor more metabolites from wastewater to enhance future studies.

Investigation on consumption of psychoactive substances and their ecological risks using wastewater-based epidemiology: a case study on Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau is the third pole of the world, and information on the consumption of psychoactive substances (PSs) in this area is scarce. In this study, we selected Qinghai Province as the research area, and the per capita consumption and prevalence of PSs were investigated using wastewater-based epidemiology. Samples from 17 wastewater treatment plants (WWTPs) in 5 major cities in Qinghai Province were monitored, and 11 PSs were detected by ultra-high performance liquid chromatography-tandem mass spectrometry. Results showed that the target compounds were detected in all samples, with relatively high concentrations of ephedrine (2.1-4825.3 ng/L) and methamphetamine (1.5-295.7 ng/L). The consumption of methamphetamine in Xining City, Haidong City, and Haixi City was up to 78.4, 16.8, and 21.2 mg/1000 inh/d (the PS consumption per 1000 inhabitants in 1 day), respectively, higher than that in the other two cities, which was the result of the different consumption patterns and its relationship with the economic levels of each city. High consumption of methadone (47.9 mg/1000 inh/day) was found in Xining City, which might be related to the methadone maintenance therapy sites in the city. Methamphetamine was the most prevalent drug, with the prevalence ranging from 0.003 (Guoluo) to 0.197% (Xining), and the prevalence of other PSs was low. The ecological risk assessment of PSs in the effluent of WWTPs showed that methadone exerted a low risk to aquatic organisms in three sites, while other substances posed potential risk or no risk. However, the long-term effect of PSs cannot be ignored.

Biomarker selection strategies based on compound stability in wastewater-based epidemiology

The specific compositions of human excreta in sewage can be used as biomarkers to indicate the disease prevalence, health status, and lifestyle of the population living in the investigated catchment. It is important for guiding and evaluating public health policies as well as promoting human health development. Among several parameters of wastewater-based epidemiology (WBE), the decay of biomarkers during transportation in sewer and storage plays a crucial role in the back-calculation of population consumption. In this paper, we summarized the stability data of common biomarkers in storage at different temperatures and in-sewer transportation. Among them, cardiovascular drugs and antidiabetic drugs are very stable which can be used as biomarkers; most of the illicit drugs are stable except for cocaine, heroin, and tetrahydrocannabinol which could be substituted by their metabolites as biomarkers. There are some losses for part of antibiotics and antidepressants even in frozen storage. Rapid detection of contagious viruses is a new challenge for infectious disease control. With the deeper and broader study of biomarkers, it is expected that the reliable application of the WBE will be a useful addition to epidemiological studies.

Building-level wastewater surveillance of SARS-CoV-2 is associated with transmission and variant trends in a university setting

The University of South Carolina (UofSC) was among the first universities to include building-level wastewater surveillance of SARS-CoV-2 to complement clinical testing during its reopening in the Fall 2020 semester. In the Spring 2021 semester, 24h composite wastewater samples were collected twice per week from 10 residence halls and the on-campus student isolation and quarantine building. The isolation and quarantine building served as a positive control site. The wastewater was analyzed using RT-ddPCR for the quantification of nucleocapsid genes (N1 and N2) to identify viral transmission trends within residence halls. Log₁₀ SARS-CoV-2 RNA concentrations were compared to both new clinical cases identified in the days following wastewater collection and recovered cases returning to sites during the days preceding sample collection to test temporal and spatial associations. There was a statistically significant positive relationship between the number of cases reported from the sites during the seven-day period following wastewater sampling and the log₁₀ viral RNA copies/L (overall IRR 1.08 (1.02, 1.16) p-value 0.0126). Additionally, a statistically significant positive relationship was identified between the number of cases returning to the residence halls after completing isolation during the seven-day period preceding wastewater sampling and the log₁₀ viral RNA copies/L (overall 1.09 (1.01, 1.17) p-value 0.0222). The statistical significance of both identified cases and recovered return cases on log₁₀ viral RNA copies/L in wastewater indicates the importance of including both types of clinical data in wastewater-based epidemiology (WBE) research. Genetic mutations associated with variants of concern (VOCs) were also monitored. The emergence of the Alpha variant on campus was identified, which contributed to the second wave of COVID-19 cases at UofSC. The study was able to identify sub-community transmission hotspots for targeted intervention in real-time, making WBE cost-effective and creating less of a burden on the general public compared to repeated individual testing methods.

The effect of long-term methadone maintenance treatment on coupling among three large-scale brain networks in male heroin-dependent individuals: A resting-state fMRI study

PURPOSE

Methadone maintenance treatment (MMT) is considered as an effective and mainstream therapy for heroin dependence. However, whether long-term MMT would improve the coupling among the three core large-scale brain networks (salience, default mode, and executive control) and its relationship with the craving for heroin is unknown.

METHODS

Forty-four male heroin-dependent individuals during long-term MMT, 27 male heroin-dependent individuals after short-term detoxification/abstinence (SA), and 26 demographically matched healthy controls (HC) underwent resting-state functional magnetic resonance imaging. We analyzed the difference in coupling among the salience, default mode, and executive control networks among the three groups and examined how the coupling among these large-scale networks was associated with craving before and after drug-cue exposure.

RESULTS

Compared with the SA group, the MMT group showed lower craving before and after cue exposure and stronger connectivity between the dorsal anterior cingulate cortex (a key node of the salience network) and key regions of the bilateral executive control network, including the bilateral dorsolateral prefrontal cortex, posterior parietal cortex, and dorsomedial prefrontal cortex. Among the heroin-dependent individuals, the functional connectivity was negatively correlated with the craving before and after heroin-cue exposure.

CONCLUSION

Our findings suggest that long-term MMT could increase the coupling between the salience and bilateral executive control networks and decrease craving for heroin. These findings contribute to the understanding of the neural mechanism of MMT, from the perspective of large-scale brain networks.

Prevalence of illicit drug consumption in a population of Hanoi: an estimation using wastewater-based epidemiology

Illicit drug use is a serious issue in Vietnam, but information about their prevalence is scarce, mainly based on seizure data. Wastewater-based epidemiology (WBE) is an alternative tool for obtaining such information, especially when stigma related to drug use can hinder survey approaches. The study aimed to apply WBE to assess the prevalence of use of a range of illicit drugs in an urban population of Vietnam. A total of 184 wastewater samples were collected at two different sites along a sewage canal, receiving sewage from over 400,000 people in Hanoi, Vietnam, in three different periods between 2018 and 2020. Illicit drugs and their metabolites were measured by direct injection using liquid chromatography-tandem mass spectrometry. The results were back-estimated, normalised to per capita daily consumption for assessement of consumption patterns and trends. Most drugs were detected in all the samples except cocaine, benzoylecgonine, amphetamine indicating a low prevalence of cocaine and amphetamine use. The estimated consumption level of methamphetamine was varied from 119.5 to 553.5 mg/d/1000 pp. The market of illicit drugs in Vietnam has changed from opiates to amphetamine-type simulants, and methamphetamine has replaced heroin as the No.1 drug, its use can be as much as 3 times more than heroin use. Moreover, we observed the considerable and potentially increasing level of ketamine consumption in Hanoi. No statistical difference was found in daily consumption per capita among days of the week for any drugs, both legal (codeine, methadone) and illegal (methamphetamine, MDMA, ketamine and heroin), suggesting the drugs were consumed mainly by regular users. This study provides important information related the illicit drug consumption in Vietnam, which will help to formulate appropriate drug control policies in this country.

Change in the chemical content of untreated wastewater of Athens, Greece under COVID-19 pandemic

COVID-19 pandemic spread rapidly worldwide with unanticipated effects on mental health, lifestyle, stability of economies and societies. Although many research groups have already reported SARS-CoV-2 surveillance in untreated wastewater, only few studies evaluated the implications of the pandemic on the use of chemicals by influent wastewater analysis. Wide-scope target and suspect screening were used to monitor the effects of the pandemic on the Greek population through wastewater-based epidemiology. Composite 24 h influent wastewater samples were collected from the wastewater treatment plant of Athens during the first lockdown and analyzed by liquid chromatography mass spectrometry. A wide range of compounds was investigated (11,286), including antipsychotic drugs, illicit drugs, tobacco compounds, food additives, pesticides, biocides, surfactants and industrial chemicals. Mass loads of chemical markers were estimated and compared with the data obtained under non-COVID-19 conditions (campaign 2019). The findings revealed increases in surfactants (+196%), biocides (+152%), cationic quaternary ammonium surfactants (used as surfactants and biocides) (+331%), whereas the most important decreases were estimated for tobacco (-33%) and industrial chemicals (-52%). The introduction of social-restriction measures by the government affected all aspects of life.

Monitoring geographical differences in illicit drugs, alcohol, and tobacco consumption via wastewater-based epidemiology: Six major cities in Turkey

A national wastewater-based epidemiology (WBE) monitoring campaign has been initiated to determine the trends in drug consumption in Turkey since 2019. This study aimed to present the wastewater monitoring results for four periods in 2019 for six major cities with 17 wastewater treatment plants. The study investigated heroin (HER), amphetamine (AMP), methamphetamine (METH), cocaine (COC), 3,4-methylenedioxymethamphetamine (MDMA), cannabis, alcohol, and tobacco to understand the temporal and geographical drug consumption trends. The results indicated a trend of regular cannabis use in all the cities. Considering geographical variations, the drug usage trends were not homogeneous within the country for any of the investigated drugs, except cannabis. HER consumption was predominant in Denizli (1042.48 mg/1000 inh/day), while İzmir and Antalya (154.10 and 79.56 mg/1000 inh/day, respectively) topped for COC consumption. Aydın had the highest consumption levels of AMP (90.03 mg/1000 inh/day) and METH (358.13 mg/1000 inh/day), while MDMA consumption was the highest in Samsun (157.64 mg/1000 inh/day). Tobacco consumption was high in Aydın (8791.69 mg/1000 inh/day) and Antalya (5375.17 mg/1000 inh/day), whereas alcohol consumption was higher in Bursa than in the other cities (53434.61 mL/1000 inh/day). There were no statistically significant differences in the weekend consumption levels of the investigated drugs among these six cities. Although this study included the results of 1 year of consumption monitoring, the data confirms internationally published information on the drug trafficking routes of conventional drugs in this region, especially the Heroin-Balkan route. Results from further sampling will enable accurate evaluation of global drug consumption and trafficking, in addition to alcohol and tobacco use.

Analysing wastewater to estimate fentanyl and tramadol use in major Chinese cities

The misuse of fentanyl and more recently tramadol in the population has caused an opioid crisis in several countries and drawn much public attention worldwide. However, there is a gap of information on the potential misuse of fentanyl and tramadol in China. This study aims to fill this gap by analysing fentanyl and tramadol in wastewater of major cities across China to estimate their use. Wastewater samples were collected from 30 cities located across all seven geographic regions of China, from 2016 to 2019. Fentanyl was detected in only a few samples, suggesting a low prevalence of this potent opioid drug in China. Meanwhile, tramadol was found in most samples with concentrations ranging up to 186 ng/L. The per capita daily consumption of tramadol estimated from wastewater across China ranged from 6 mg/d/1000 in. to 213 mg/d/1000 inh. The consumption of tramadol seems to be similar among all the days of the week. Tramadol use is overall higher in Northeast China than in other regions, which is different from heroin, another popular opioid in China. Temporally, there is a significant decrease in tramadol use in major cities of China from 2016 to 2019. The results of our study suggested that tramadol use in China was predominantly from pharmaceutical prescription and not as prevalent as in other countries.

Estimating population-level of alcohol, tobacco and morphine use in a small Russian region using wastewater-based epidemiology

INTRODUCTION

Alcohol, tobacco and illicit drug use combined are the largest modifiable health risk factors. Wastewater-based epidemiology (WBE) is a complementary approach for monitoring substance use in the population. In this study we applied WBE technique to a community in the Moscow region to estimate population-level consumption of alcohol, tobacco and morphine.

METHODS

Wastewater sampling was carried out over 47 days, in 2018 and 2019, including the New Year period. Analysis of the samples for consumption biomarkers (ethyl sulphate, cotinine and morphine) were undertaken using liquid chromatography tandem mass spectrometry (LC-MS/MS). Daily consumption estimates were then compared with sales/production/prescription data and between different days of the week using Mann-Whitney U test.

RESULTS

Alcohol consumption was significantly higher on Sundays and during the New Year and Russian Christmas period compared to weekdays and Saturdays. Tobacco consumption estimates were largely consistent throughout the week. Morphine was detected by WBE during the monitoring period but was inconsistent with prescription record data.

DISCUSSION AND CONCLUSIONS

This study provides evidence for the feasibility of conducting WBE in Russia. Estimates of alcohol consumption derived from WBE were higher than average alcohol sales data for the country. The estimated consumption of nicotine is generally consistent with the production data, with estimates higher than in most other countries. Our results also suggest potential illegal use of opioids (morphine-based) in the population. Given the considerable health and economic costs of substance use in Russia, more extensive WBE testing is recommended to inform and evaluate public health policies.

Simultaneous Determination of Seven Antibiotics and Five of Their Metabolites in Municipal Wastewater and Evaluation of Their Stability under Laboratory Conditions

The selection and spread of antibiotic resistance poses risks to public health by reducing the therapeutic potential of antibiotics against human pathogens. Wastewater-based epidemiology (WBE) is potentially the most reliable approach to estimate antibiotics use. Previous WBE studies used parent antibiotics as biomarkers, which may lead to overestimation since parent antibiotics may be directly disposed of. Using metabolites as biomarkers can avoid this drawback. This study developed a simultaneous solid-phase extraction coupled with ultra-high-performance liquid chromatography tandem mass spectrometry method for analyzing 12 antibiotics and human metabolites in wastewater to help assess health risk. Optimum conditions were achieved using a PEP cartridge at pH 3.0. The extraction efficiencies were 73.3~95.4% in influent and 72.0~102.7% in effluent for most of the target analytes. Method detection limit ranged from 0.1 to 1.5 ng/L for influent wastewater and 0.03 to 0.7 ng/L for effluent wastewater. A stability experiment showed that sulfonamide parents and their metabolites were stable at 4 °C, −20 °C and −80 °C, while macrolides metabolites were more stable than their corresponding parents at 4 °C and −20 °C. Finally, the method was applied to measure these analytes in wastewater samples collected from three Beijing WWTPs and to derive apparent removal rates. All metabolites were detected in wastewater samples with concentrations ranging from 1.2 to 772.2 ng/L in influent, from <MDL to 235.6 ng/L in effluent. The apparent removal rates of five metabolites were above 72.6%. These results set a solid foundation for applying WBE to evaluate antibiotics use and its public health effects.

"Waste Not, Want Not" - Leveraging Sewer Systems and Wastewater-Based Epidemiology for Drug Use Trends and Pharmaceutical Monitoring

During the current global COVID-19 pandemic and opioid epidemic, wastewater-based epidemiology (WBE) has emerged as a powerful tool for monitoring public health trends by analysis of biomarkers including drugs, chemicals, and pathogens. Wastewater surveillance downstream at wastewater treatment plants provides large-scale population and regional-scale aggregation while upstream surveillance monitors locations at the neighborhood level with more precise geographic analysis. WBE can provide insights into dynamic drug consumption trends as well as environmental and toxicological contaminants. Applications of WBE include monitoring policy changes with cannabinoid legalization, tracking emerging illicit drugs, and early warning systems for potent fentanyl analogues along with the resurging wave of stimulants (e.g., methamphetamine, cocaine). Beyond drug consumption, WBE can also be used to monitor pharmaceuticals and their metabolites, including antidepressants and antipsychotics. In this manuscript, we describe the basic tenets and techniques of WBE, review its current application among drugs of abuse, and propose methods to scale and develop both monitoring and early warning systems with respect to measurement of illicit drugs and pharmaceuticals. We propose new frontiers in toxicological research with wastewater surveillance including assessment of medication assisted treatment of opioid use disorder (e.g., buprenorphine, methadone) in the context of other social burdens like COVID-19 disease.

Assessing patterns of illicit drug use in a Chinese city by analyzing daily wastewater samples over a one-year period

Wastewater-based epidemiology (WBE) has been used extensively around the globe to provide information on illicit drug consumption. In China, most WBE studies to date only include a limited number of samples per catchment, making it difficult to derive any temporal consumption patterns. This study addresses this knowledge gap by identifying the temporal consumption trends of nine drugs in a Chinese megacity using WBE over a one-year period. Daily influent samples (n = 279) were collected from a wastewater treatment plant serving ~500,000 residents. All target drugs showed similar levels of consumption throughout the week. These findings were different to previous WBE studies in developed countries, where amphetamine-type drugs have shown higher consumption on weekends than during the week. Such a difference could be due to the users' demographics and behaviors as reported in previous surveys and warrant more research to help formulate appropriate drug control policies in China. Our study also observed that declining methamphetamine and ketamine consumption between 2012 and 2018, while consumption of MDMA and methadone were stable over the same period.

Wastewater analysis of psychoactive drugs: Non-enantioselective vs enantioselective methods for estimation of consumption

The consumption of licit and illicit psychoactive drugs (PAD) is ubiquitous in all communities and a serious public health problem. Measuring drug consumption is difficult but essential for health-care professionals, risk assessment and policymakers. Different sources of information have been used for a comprehensive analysis of drug consumption. Among them, Wastewater based epidemiology (WBE) emerged as an essential and complementary methodology for estimating licit and illicit drugs consumption. This methodology can be used for quantification of unchanged drugs or their human-specific metabolites in wastewater for estimation of consumption or screening of new PAD. Although some limitations are still being pointed out (e.g., estimation of the population size, use of suitable biomarkers or pharmacokinetics studies), the non-invasive and potential for monitoring real-time data on geographical and temporal trends in drug use have been showing its capacity as a routine and complementary tool. Chromatographic methods, both non-enantioselective and enantioselective are the analytical tools used for quantification of PAD in wastewaters and further estimation of consumption. Therefore, this manuscript aims to summarize and critically discuss the works used for wastewater analysis of PAD based on WBE using non-enantioselective and enantioselective methods for estimation of consumption. Non-enantioselective methods are among the most reported including for chiral PAD. Nevertheless, a trend has been seen towards the development of enantioselective methods as most PAD are chiral and determination of the enantiomeric fraction can provide additional information (e.g., distinction between consumption or direct disposal, or manufacture processes) and fulfill some WBE gaps.

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.

Evaluation of Illicit Drug Consumption by Wastewater Analysis Using Polar Organic Chemical Integrative Sampler as a Monitoring Tool

Illicit drug abuse is a worldwide social and health problem, and monitoring illicit drug use is of paramount importance in the context of public policies. It is already known that relevant epidemiologic information can be obtained from the analysis of urban residual waters. This approach, named wastewater-based epidemiology (WBE), is based on the measurement of specific markers, resulting from human biotransformation of the target drugs, as indicators of the consumption of the compounds by the population served by the wastewater treatment installation under investigation. Drug consumption estimation based on WBE requires sewage sampling strategies that express the concentrations along the whole time period of time. To this end, the most common approach is the use of automatic composite samplers. However, this active sampling procedure is costly, especially for long-term studies and in limited-resources settings. An alternative, cost-effective, sampling strategy is the use of passive samplers, like the polar organic chemical integrative sampler (POCIS). POCIS sampling has already been applied to the estimation of exposure to pharmaceuticals, pesticides, and some drugs of abuse, and some studies evaluated the comparative performances of POCIS and automatic composite samplers. In this context, this manuscript aims to review the most important biomarkers of drugs of abuse consumption in wastewater, the fundamentals of POCIS sampling in WBE, the previous application of POCIS for WBE of drugs of abuse, and to discuss the advantages and disadvantages of POCIS sampling, in comparison with other strategies used in WBE. POCIS sampling is an effective strategy to obtain a representative overview of biomarker concentrations in sewage over time, with a small number of analyzed samples, increased detection limits, with lower costs than active sampling. Just a few studies applied POCIS sampling for WBE of drugs of abuse, but the available data support the use of POCIS as a valuable tool for the long-term monitoring of the consumption of certain drugs within a defined population, particularly in limited-resources settings.

Illicit synthetic opioid consumption in Asia and the Pacific: Assessing the risks of a potential outbreak

BACKGROUND

Illegally manufactured potent synthetic opioids (IMPSO) like fentanyl have contributed to rises in overdose deaths in parts of North America and Europe. While many of these substances are produced in Asia, there is little evidence they have entered markets there. We consider the susceptibility to IMPSO's encroachment in markets in the Asia-Pacific region.

METHODS

Our analysis focuses on Australia, China, India, and Myanmar. Using a mixed-methods approach comprising interviews, literature review, and secondary data analyses, we examine factors facilitating or impeding incursion of IMPSO. Finally, we illustrate the potential for IMPSO fatalities in Australia.

RESULTS

Australia reports some signs of three facilitating factors to IMPSO's emergence: 1) existing illicit opioid markets, 2) disruption of opioid supply, and 3) user preferences. The other three countries report only existing illicit opioid markets. While diverted pharmaceutical opioids are a noted problem in Australia and India, heroin is the dominant opioid in all four countries. There are divergent trends in heroin use, with use declining in China, increasing in India, and stable in Australia and Myanmar. If IMPSO diffused in Australia as in North America from 2014 to 2018, and our assumptions generally hold, deaths from IMPSO could range from 1500-5700 over a five-year period.

CONCLUSIONS

This analysis and illustrative calculations serve as an early indication for policymakers. With the exception of Australia, many countries in the region fail to properly record overdose deaths or monitor changes in local drug markets. Early assessment and monitoring can give officials a better understanding of these changing threats.

Effect of Coronavirus Disease 2019 on the Psychology and Behavior of Patients on Methadone Maintenance Treatment in Wuhan, China: A Clinical Observational Study

Methadone maintenance treatment (MMT) is a national strategy adopted for the treatment of heroin dependency in China. The sudden outbreak of coronavirus disease 2019 (COVID-19) and the resultant social isolation in Wuhan have also had a significant negative impact on local patients undertaking MMT. In this study, 76 patients on MMT from the Wuhan First Health Clinic were selected as the research objects to investigate the effect of COVID-19 on the levels of stress, anxiety, and depression, as well as the withdrawal symptoms and craving and substance use. Our results revealed that, during the outbreak, the Perceived Stress Scale (PSS) score, HAMA score, HAMD score, and craving in the included patients was significantly higher than that at the baseline and post-epidemic (p < 0.01, p < 0.01, p < 0.01, p < 0.01, respectively); the positive rate of morphine and methamphetamine urine test was significantly lower than that the post-epidemic (p = 0.01, p < 0.01, respectively); the amount of tobacco used during the outbreak and the post-epidemic period was significantly higher than that at the baseline (p < 0.01, p < 0.01, respectively), while the amount of alcohol consumed at the outbreak was significantly higher than at the baseline and the post-epidemic (p < 0.01, p < 0.01, respectively). The negative emotions aroused by the COVID-19 outbreak and the accompanying social isolation to patients on MMT are an important factor of negative reinforcement that adversely affected the patients' craving for drugs and the consumption of legal substances. This finding suggests the need to strengthen the psychological counseling for patients on MMT during severe epidemic, actively alleviating the negative emotions, reducing the risk of substance abuse, and strengthening drug management after the epidemic to prevent the rise of substance (legal or illegal) abuse.

A revised excretion factor for estimating ketamine consumption by wastewater-based epidemiology - Utilising wastewater and seizure data

The rate of drug excretion (excretion factor) is a critical parameter for monitoring drug consumption in the population by wastewater-based epidemiology (WBE). Previous studies have refined excretion factors for common illicit drugs, such as cocaine, amphetamine, methamphetamine, heroin, to improve the accuracy and reduce uncertainty in back-calculating consumption. Nevertheless, for ketamine, one of the most prevalent psychoactive substances, a careful review of its excretion factors has not been performed due to limited pharmacokinetic data. Here we review WBE studies and seizure data to refine and validate the excretion factors for ketamine and norketamine. The average ketamine/norketamine ratio in wastewater (5.36) was much higher than that found in urine (0.64), which means that the excretion factors derived only from pharmacokinetics data are not appropriate. Based on the comparison of the ratio between estimated consumptions of ketamine and methamphetamine by WBE with their corresponding ratio in official seizure data, a revised WBE excretion factor of 20% was proposed for ketamine following this review and applied to estimate the ketamine consumption in China. The revised estimates of ketamine consumption corresponded well with drug statistics. This suggests that the revised ketamine excretion factor is appropriate for estimating ketamine consumption by WBE. Systematic review of WBE studies is a suitable approach to refine the excretion factors for substances with inadequate pharmacokinetic data.

Occurrence and Fate of Heavy Metals in Municipal Wastewater in Heilongjiang Province, China: A Monthly Reconnaissance from 2015 to 2017

As one of the major sources of pollutions in the environments, effluents from municipal wastewater recently became a hot topic. This study quantified monthly county-level releases of five heavy metals, i.e., lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg), from municipal wastewater into the environment in the Heilongjiang Province of China, based on sampling, measurement, and modeling tools. Wastewater samples were collected from 27 municipal wastewater treatment plants (MWTPs) in 15 county-level cities of Heilongjiang every month from 2015 to 2017. The concentrations of five heavy metals were analyzed in both influents (Pb: 160 ± 100 μg/L; Cd: 15 ± 9.0 μg/L; Cr: 170 ± 64 μg/L; Hg: 0.67 ± 1.5 μg/L; As: 6.2 ± 4.8 μg/L) and effluents (Pb: 45 ± 15 μg/L; Cd: 5.2 ± 5.1 μg/L; Cr: 57 ± 13 μg/L; Hg: 0.28 ± 0.12 μg/L; As: 2.6 ± 1.4 μg/L). The removal ratios of the five heavy metals ranged from 50% to 67%. Inflow fluxes of Pb, Cr, and Cd displayed increasing trends first then decreased after reaching a maximum value, whereas those of Hg and Pb remained stable. Material flow analysis reveals that constructions of MWTPs are conducive to significantly reduce the releases of heavy metals from urban areas into the aquatic environment in the study area. Additionally, municipal wastewater sludge (used as fertilizer or spread on the land) could be a significant source of heavy metals in the land.

Using wastewater-based epidemiology to estimate consumption of alcohol and nicotine in major cities of China in 2014 and 2016

Monitoring the use of alcohol and tobacco in the population is important for public health planning and evaluating the efficacy of intervention strategies. The aim of this study was to use wastewater-based epidemiology (WBE) to estimate alcohol and tobacco consumption in a number of major cities across China and compare WBE estimates with other data sources. Daily composite influent wastewater samples were collected from wastewater treatment plants (WWTPs) across China in 2014 (n = 53) and 2016 (n = 45). The population-normalized daily consumption estimated by WBE were compared with other data sources where available. The average consumption of alcohol was 8.1 ± 7.0 mL ethanol/person aged 15+/day (EPD) in the investigated cities of 2016 while those involved in 2014 had an average consumption of 4.7 ± 3.0 EPD. The average tobacco consumption was estimated to be 3.7 ± 2.2 cigarettes/person aged 15+/day (CPD) in 2016 and 3.1 ± 1.9 CPD in 2014. The changes in the average consumption in those cities from 2014 to 2016 were supported by the results from a limited number of WWTPs where samples were collected in both years. Consumption of alcohol and tobacco in urban China is at a medium level compared with other countries on a per capita basis. WBE estimates of tobacco consumption were relatively comparable with results of traditional surveys and sales statistics. WBE estimates of alcohol consumption were lower than WHO survey results, probably due to EtS degradation and uncertainty in the EtS excretion factor.

Monitoring Consumption of Common Illicit Drugs in Kuala Lumpur, Malaysia, by Wastewater-Cased Epidemiology

Southeast Asian countries including Malaysia play a major role in global drug trade and abuse. Use of amphetamine-type stimulants has increased in the past decade in Malaysia. This study aimed to apply wastewater-based epidemiology for the first time in Kuala Lumpur, Malaysia, to estimate the consumption of common illicit drugs in urban population. Influent wastewater samples were collected from two wastewater treatment plants in Kuala Lumpur in the summer of 2017. Concentrations of twenty-four drug biomarkers were analyzed for estimating drug consumption. Fourteen drug residues were detected with concentrations of up to 1640 ng/L. Among the monitored illicit drugs, 3,4-methylenedioxy-methamphetamine (MDMA) or ecstasy had the highest estimated per capita consumptions. Consumption and dose of amphetamine-type stimulants (methamphetamine and MDMA) were both an order of magnitude higher than those of opioids (heroin and codeine, methadone and tramadol). Amphetamine-type stimulants were the most prevalent drugs, replacing opioids in the drug market. The prevalence trend measured by wastewater-based epidemiology data reflected the shift to amphetamine-type stimulants as reported by the Association of Southeast Asian Nations Narcotics Cooperation Center. Most of the undetected drug residues were new psychoactive substances (NPSs), suggesting a low prevalence of NPSs in the drug market.