Challenges and opportunities in using wastewater analysis to measure drug use in a small prison facility

New trends of drug abuse in custodial settings: A systematic review on the misuse of over-the-counter drugs, prescription-only-medications, and new psychoactive substances

The article presents a systematic literature review on the use and the psychiatric implications of over-the-counter drugs (OTC), prescription-only-medications (POM), and new psychoactive substances (NPS) within custodial settings. The searches wer carried out on 2 November 2022 on PubMed, Scopus, and Web of Science in line with PRISMA guidelines. A total of 538 records were identified, of which 37 met the inclusion criteria. Findings showed the most prevalent NPS and OTC and POM classes reported in prisons were synthetic cannabinoids receptor agonists (SCRAs) and opioids, respectively. NPS markets were shown to be in constant evolution following the pace of legislations aimed to reduce their spread. The use of such substances heavily impacts the conditions and rehabilitation of persons in custody, with consequent physical and mental health risks. It is important to raise awareness of the use and misuse of such substances in prisons (i) from an early warning perspective for law enforcement and policy makers (ii) to prompt doctors to cautiously prescribe substances that may be misused (iii) to improve and increase access to treatment provided (iv) to add such substances to routine toxicological screening procedures (v) to improve harm reduction programmes.

Psychiatric and legal considerations for ketamine treatment within prison settings

The fundamental right to equivalence of health care in prison settings encompasses the provision of medication to address mental health conditions. Considering the increased risk for self-harm among individuals dealing with depression, the limited effectiveness of conservative antidepressants is a major challenge in psychiatry. The high prevalence of suicidal tendencies within prison populations underscores the imperative for state-of-the-art pharmacological treatment to uphold adequate health care standards. Notably, the denial of access to effective medication could be deemed a violation of human rights of people living in prison according to international treaties, domestic law, and United Nations normative standards of detention. This article presents the authors' perspective on the accessibility of ketamine treatment in prison settings, discussing psychiatric and legal considerations as well as current challenges in this context. Implementing novel psychopharmacological interventions may alleviate the distress experienced by individuals struggling with depressive symptoms and suicidality. At the same time, unprecedented treatment alternatives bring along potential issues, including limited understanding of long-term effects and the risk of abuse. Given the scarce data-availability, a pressing need exists for further research on the benefits and risks of ketamine treatment within prison populations.

Correlations between China's socioeconomic status, disease burdens, and pharmaceuticals and personal care product levels in wastewater

The presence of pharmaceutical and personal care products (PPCPs) in domestic wastewater can potentially indicate socioeconomic status and disease burdens. However, current knowledge is limited to the correlation between specific pharmaceuticals and diseases. This study aims to explore the associations between socioeconomic status, disease burdens, and PPCP levels in domestic wastewater at a national level. Samples from 171 wastewater influents across China were used to measure PPCPs, and the per capita consumption of PPCPs was calculated. Results showed that the 31 targeted PPCPs were widely present in wastewater with varying occurrence characteristics. The mean consumption levels of different PPCPs varied greatly, ranging from 0.03 to 110723.15 µg/d/capita. While there were no significant regional differences in the overall pattern of PPCP consumption, 22 PPCPs showed regional variations between Northern China and Southern China. PPCPs with similar usage purposes exhibited similar distribution patterns. Disease burden (70.1%) was the main factor affecting most PPCP consumption compared to socioeconomic factors (26.4%). Through correlation analyses, specific types of PPCPs were identified that were highly associated with socioeconomic status and disease burdens, such as hypertension-bezafibrate, brucellosis-quinolones, sulfonamides, hepatitis-triclosan, triclocarban, socioeconomic development-fluoxetine, and people's living standards-gemfibrozil. Despite some uncertainties, this study provides valuable insights into the relationship between PPCPs in domestic wastewater and socioeconomic status and human health.

Wastewater analysis for new psychoactive substances and cocaine and cannabis in a Northern Ireland Prison

The global drug market has been significantly impacted by the emergence of new psychoactive substances, leading to challenges in creating effective legislative controls and their use within recreational drug consumption. This research explores the prevalence of new psychoactive substances and non-medicinal and medicinal compounds within a prison facility in Northern Ireland. Wastewater samples collected from seven different manholes within the prison were analysed for 37 target compounds including the two most found illicit substances: benzoylecgonine (primary metabolite of cocaine) and cannabis. Using solid phase extraction with Oasis HLB and liquid-chromatography-time-of-flight-mass spectrometry across a gradient of 9 min, our analysis revealed that benzoylecgonine was the sole compound consistently present in all collected samples. Following this finding, our target compound selection was broadened to encompass medicinal compounds and employing qualitative analysis we re-evaluated the samples and discovered the presence of buprenorphine, benzodiazepines, methadone, morphine, and codeine. Finally, the study explored the application of enzymatic beta-glucuronidase hydrolysis to the samples. This final phase yielded significant findings, indicating the presence of codeine and nordiazepam at higher peak intensities, thereby shedding light on the potential implications of this enzymatic process.

Monitoring medication and illicit drug consumption in a prison by wastewater-based epidemiology: Impact of COVID-19 restrictions

Drug consumption in prisons is a concern for the safety of incarcerated people and staff. Typically, drug use prevalence in prisons is estimated through urinalysis and intelligence operations, which can be intrusive and stressful. An alternative approach, wastewater-based epidemiology (WBE), was used in this study to estimate the consumption of licit and illicit drugs for the entire population of a prison in Australia. Wastewater samples were collected from March to December 2020, covering periods of no restrictions and periods when prison access was restricted to prevent the transmission of COVID-19. Target biomarkers were analysed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The average consumption of common illicit drugs (MDMA, methamphetamine and cocaine) over the sampling period in the prison (0.5 - 4.5 mg/1000 people/day) was two to three orders of magnitude lower than in the community population (254 - 1000 mg/1000 people/day). Comparison of WBE estimates against pharmacy dispensing data suggested potential illicit buprenorphine consumption at the prison. Methamphetamine and buprenorphine use decreased when no visitors were allowed (18% - 72% decrease for methamphetamine; about half decrease for buprenorphine) and increased once these restrictions were eased (22% - 39% increase for methamphetamine; 44% - 67% increase for buprenorphine). The changes in drug use may be attributed in part to a reduction of drug trafficking into the prison from visitors or non-essential staffs and in part to the reduced contribution of urine from staff who used toilets within the prison. This study provided useful information on the scale of illicit drug use and extra-medical use of licit drugs in prison, and its changes under different security conditions.

Health and correctional staff acceptability of depot buprenorphine in NSW prisons

BACKGROUND

Provision of opioid agonist treatment (OAT) in custodial settings is resource-intensive and may be associated with diversion, non-medical use, and violence. A clinical trial of a new OAT, depot buprenorphine (the UNLOC-T study), provided the opportunity to obtain health and correctional staff perspectives regarding this treatment prior to widespread roll-out.

METHODS

Sixteen focus groups with 52 participants were conducted, including 44 health staff (nurses, nurse practitioners, doctors, and operational staff) and eight correctional staff.

RESULTS

Key challenges to providing OAT identified as potentially being addressed by depot buprenorphine included 1) patient access, 2) OAT program capacity, 3) treatment administration procedures, 4) medication diversion and other safety issues and, 5) impact on other service delivery.

CONCLUSIONS

The introduction of depot buprenorphine into correctional settings was considered to have the potential to increase safety for patients, improve staff / patient relations and advance patient health outcomes via expanded treatment coverage and efficiencies gained through enhanced health service delivery. Support was almost universal from both correctional and health staff participating in this study. These findings build on emerging research regarding the positive impact of more flexible OAT programs and could be used to engage support for the implementation of depot buprenorphine from staff in other secure settings.

NPS detection in Prison: a Systematic Literature Review of Use, Drug Form, and Analytical Approaches

This paper presents a systematic literature review on the detection of new psychoactive substances (NPS) in prison settings. It includes the most frequently reported NPS classes, the routes and forms used for smuggling, and the methods employed to analyze biological and non-biological samples. The search was carried out using MEDLINE (EBSCO), Scopus (ELSEVIER), PubMed (NCBI) and Web of Science (Clarivate) databases, along with reports from the grey literature in line with the PRISMA-S guidelines. A total of 2708 records were identified, of which 50 met the inclusion criteria. Findings showed the most prevalent NPS class reported in prison was synthetic cannabinoids (SCs). The most frequently reported SCs in non-biological samples were 4F-MDMB-BINACA, MDMB-4en-PINACA, and 5F-ADB. These were smuggled mainly through the postal services deposited on paper or herbal matrices. Concentrations of SCs detected on seized paper ranged between 0.05-1.17 mg/cm² . The SCs most frequently reported in biological specimens (i.e., urine, blood, saliva, and wastewater) were 5F-MDMB-PICA, 4F-MDMB-BINACA and MDMB-4en-PINACA. Concentrations of SCs reported in femoral blood and serum were 0.12-0.48 ng/ml and 34-17 ng/ml, respectively. Hyphenated techniques were predominantly employed and generally successful for the detection of NPS in biological (i.e., LC-HRMS/MS) and non-biological samples (i.e., LC-HRMS/MS and GC-MS. The on-site technique IMS showed promise for detecting SCs in various forms, however immunoassays were not recommended. Future work should focus on accurate in-field detection of SCs deposited on paper and in urine and saliva to improve real-time decision-making, as well as wastewater and air monitoring for overall drug use trends.

Current and future perspectives for wastewater-based epidemiology as a monitoring tool for pharmaceutical use

The medical and societal consequences of the misuse of pharmaceuticals clearly justify the need for comprehensive drug utilization research (DUR). Wastewater-based epidemiology (WBE) employs the analysis of human metabolic excretion products in wastewater to monitor consumption patterns of xenobiotics at the population level. Recently, WBE has demonstrated its potential to evaluate lifestyle factors such as illicit drug, alcohol and tobacco consumption at the population level, in near real-time and with high spatial and temporal resolution. Up until now there have been fewer WBE studies investigating health biomarkers such as pharmaceuticals. WBE publications monitoring the consumption of pharmaceuticals were systematically reviewed from three databases (PubMed, Web of Science and Google Scholar). 64 publications that reported population-normalised mass loads or defined daily doses of pharmaceuticals were selected. We document that WBE could be employed as a complementary information source for DUR. Interest in using WBE approaches for monitoring pharmaceutical use is growing but more foundation research (e.g. compound-specific uncertainties) is required to link WBE data to routine pharmacoepidemiologic information sources and workflows. WBE offers the possibility of i) estimating consumption of pharmaceuticals through the analysis of human metabolic excretion products in wastewater; ii) monitoring spatial and temporal consumption patterns of pharmaceuticals continuously and in near real-time; and iii) triangulating data with other DUR information sources to assess the impacts of strategies or interventions to reduce inappropriate use of pharmaceuticals.

Estimation of the psychoactive substances consumption within 12 wastewater treatment plants service areas in a certain city of Guangxi, China applying wastewater-based epidemiology

The abuse of psychoactive substances has been increasing dramatically over the last few years, which is becoming a concern for human health and social stability. How to accurately estimate psychoactive substances' total consumption in certain areas is the key to manage such substances. In order to control psychoactive substances, 8 psychoactive substances' consumption within 12 wastewater treatment plants (WWTPs) service areas in a certain city of Guangxi, China was investigated in 2019. Firstly, a solid-phase extraction-liquid chromatography-tandem mass spectrometry method was used to determine the influent concentrations. Morphine (MOR), 3, 4-methylenedioxymethamphetamine (MDMA), methamphetamine (METH), ketamine (KET), and norketamine (NK) were detected, with the concentrations ranging from less than method detection limit (NK, MDMA) to 170.91 (METH) ng/L. Then, the back-estimation of consumption was conducted according to the objective and near real-time wastewater-based epidemiology (WBE). The results demonstrate that KET, MOR, and METH are the most abused psychoactive substances, with the mean consumption of 682.42, 167.81, and 44.56 mg/day/1000 inh, respectively. The psychoactive substance residues of WWTPs influent were analyzed to estimate such substances' consumption in specific areas, so as to provide support for risk prevention and control.

Analysis of 39 drugs and metabolites, including 8 glucuronide conjugates, in an upstream wastewater network via HPLC-MS/MS

Pharmaceutical compounds ingested by humans are metabolized and excreted in urine and feces. These metabolites can be quantified in wastewater networks using wastewater-based epidemiology (WBE) methods. Standard WBE methods focus on samples collected at wastewater treatment plants (WWTPs). However, these methods do not capture more labile classes of metabolites such as glucuronide conjugates, products of the major phase II metabolic pathway for drug elimination. By shifting sample collection more upstream, these unambiguous markers of human exposure are captured before hydrolysis in the wastewater network. In this paper, we present an HPLC-MS/MS method that quantifies 8 glucuronide conjugates in addition to 31 parent and other metabolites of prescription and synthetic opioids, overdose treatment drugs, illicit drugs, and population markers. Calibration curves for all analytes are linear (r2 > 0.98), except THC (r2 = 0.97), and in the targeted range (0.1-1,000 ng mL-1) with lower limits of quantification (S/N = 9) ranging from 0.098 to 48.75 ng mL-1. This method is fast with an injection-to-injection time of 7.5 min. We demonstrate the application of the method to five wastewater samples collected from a manhole in a city in eastern Massachusetts. Collected wastewater samples were filtered and extracted via solid-phase extraction (SPE). The SPE cartridges are eluted and concentrated in the laboratory via nitrogen-drying. The method and case study presented here demonstrate the potential and application of expanding WBE to monitoring labile metabolites in upstream wastewater networks.

Mining chemical information in Swedish wastewaters for simultaneous assessment of population consumption, treatment efficiency and environmental discharge of illicit drugs

Consumption of illicit drugs poses health risks to the public and environment. Knowledge on their usage helps better implementations of intervention strategies to reduce drug-related harms in the society and also policies to limit their releases as emerging contaminants to recipient environments. This study aimed to investigate from the daily consumption to treatment efficiency and subsequent discharge of illicit drugs by the Swedish urban populations based on simultaneous collection and analysis of influent and effluent wastewater. Two different weekly monitoring campaigns showed similar drug prevalence in Stockholm and Uppsala, with amphetamine as the most popular drug. Almost all target drug residues were still measurable in effluent wastewater. High removal efficiencies (> 94%) were observed for amphetamine, cocaine and benzoylecgonine, whereas ketamine, 3,4-methylenedioxymethamphetamine (MDMA), mephedrone and methamphetamine were the least removed substances (< 64%), with the highest discharge observed for MDMA in both catchments (~ 3.0 g/day in Uppsala; ~ 18 g/day in Stockholm). Our study provides new insights into short-term changes in the use and related discharge of illicit drugs by urban populations. Such wastewater monitoring can provide useful information to public health, forensic and environmental authorities in planning future intervention and regulation policies.

Systematic Evaluation of the In-Sample Stability of Selected Pharmaceuticals, Illicit Drugs, and Their Metabolites in Wastewater

The in-sample stability of selected pharmaceuticals, illicit drugs, and their metabolites in wastewater was assessed under six different conditions-untreated, addition of hydrochloric acid or sodium metabisulfite solution, combined with or without sterile filtration, and at four representative temperatures, at 35 °C for up to 28 days, 22 °C for 56 days, and 4 °C and -20 °C for 196 days, or freeze/thaw cycles for 24 weeks. Paracetamol, 6-monoacetylmorphine, morphine, and cocaine were poorly stable in untreated wastewater-e.g., with 50% transformation within 1.2-8.1 days at 22 °C, and acidification reduced their in-sample transformations. Acesulfame, carbamazepine, cotinine, methamphetamine, 3,4-methylenedioxy-methamphetamine (MDMA), ketamine, norfentanyl, 3,4-methylenedioxy-N-ethylamphetamine (MDEA), and norbuprenorphine were highly or moderately stable over the observed period, even in untreated wastewater. Fitting of pseudo-first-order kinetics and the Arrhenius equation was used to develop a multistage transformation estimation model combined with an interactive tool to evaluate possible transformation scenarios of selected biomarkers for the processes from sampling to preanalysis. However, as the wastewater composition can vary between sites and over time, the variability of in-sample stability requires further exploration.

Air monitoring for synthetic cannabinoids in a UK prison: Application of personal air sampling and fixed sequential sampling with thermal desorption two-dimensional gas chromatography coupled to time-of-flight mass spectrometry

In recent years, there have been increasing complaints from staff working in UK prisons of secondary exposure to psychoactive drug fumes, often believed to be synthetic cannabinoids. Our pilot study aimed to provide an initial evidence base for this issue and reveal compounds of interest within indoor prison air. Here, we present a new method for the detection of synthetic cannabinoids in air and demonstrate its application in a UK prison. Air sampling was conducted using a fixed sequential sampler, alongside personal air sampling units worn by prison officers within an English prison. Air samples were collected onto thermal desorption (TD) tubes and analysed via comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF MS). This study is the first of its kind in a prison setting, and the approach is of importance to analytical scientists, policy makers and public health employees tasked with the health and safety of prison staff. GC × GC-TOF MS analysis was able to separate and identify a range of compounds present in the prison air samples. Analysis of the TD tubes did not reveal any synthetic cannabinoids from the fixed pump air samples or the personal pump samples worn by prison officers. Air monitoring in prisons presents a challenge of logistics and science. Fixed sequential air sampling combined with personal air monitoring devices allowed air from multiple locations within a prison to be collected, providing a comprehensive approach to evaluating the air that prison staff is exposed to during a fixed time period.

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.

The cardiovascular health of prisoners who use cannabis: An exploratory study among hospitalised prisoners

OBJECTIVE

It is essential that health professionals who practice medicine in prison rely on accurate knowledge about their patients to provide them with adapted care. The use of cannabis can influence the health status of prisoners, but data are lacking regarding the potentially related adverse health consequences. The objective of this descriptive study was to describe the cardiovascular outcomes related to cannabis use in prisoners from several detention centres hospitalised in a French hospital.

METHODS

In France, prisoners who require a longer than 48-hour hospitalisation are admitted in specific secured polyvalent units called inter-regional secured hospital units (ISHU). Hospitalisations in the ISHU of Toulouse University Hospital between 2012 and 2016 for cardiovascular disorders potentially related to the use of cannabis were extracted from the French hospital database and analysed using a previously validated methodology. Included patients were those hospitalised for an inaugural cardiovascular event or deterioration of a preexisting cardiovascular illness who declared having used cannabis while imprisoned.

RESULTS

Overall, 31 cardiovascular outcomes were identified in cannabis-using hospitalised prisoners among 411 hospitalisations for cardiovascular disorders (all men, mean age 43±SD years old). All used cannabis (daily: 56%) and tobacco (more than 15 PY: 83.3%), 5 used cocaine, and none used alcohol. The most frequent were coronaropathy (n=13), followed by obliterating arteriopathy of the lower limb (OALL, n=7), arrhythmic cardiomyopathy (n=4), venous thrombosis (n=3), infectious cardiopathy (n=2), and ischemic stroke (n=2).

CONCLUSION

This description of serious cardiovascular outcomes in prisoners who use cannabis provides insights into the clinical features possibly observed in this vulnerable population The findings indicate that 7.5% of hospitalizations of prisoners for cardiovascular disorders are potentially linked to cannabis used in prison.

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.

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.

Longitudinal injecting risk behaviours among people with a history of injecting drug use in an Australian prison setting: The HITS-p study

BACKGROUND

HCV transmission remains high in prisons globally. Understanding injecting risk behaviours in prisons is crucial to effectively develop and implement HCV prevention programs in this setting including treatment as prevention.

METHODS

HITS-p is a cohort study which enrolled people with a history of injecting drug use in prisons in NSW, Australia from 2005 to 2013. Participants completed an interview at enrolment and follow-up visits to determine injecting behaviours. Generalized estimating equation (GEE) and logistic regression methods were used to assess injecting risk behaviours prior to and following prison entry and to investigate injecting risk behaviours in prison.

RESULTS

Overall, 499 participants with a history of injecting drug use were included (median age, 26 years; 65% male). Participants were significantly less likely to inject drugs following incarceration. Among injectors, participants were less likely to inject ≥weekly but more likely to share a needle/syringe. At enrolment, the proportion reporting any injecting, ≥weekly injecting, and needle/syringe sharing in prison was highest among younger individuals. Younger age was associated with both re-initiation and continuation of injecting drug use following prison entry. Among those continuously imprisoned, younger age was associated with increased odds of any injecting, ≥weekly injecting, and sharing a needle/syringe.

CONCLUSIONS

Upon entry to prison, injecting drug use decreased but syringe sharing increased among injectors. Younger individuals are most likely to exhibit high-risk injecting behaviours in prison. These data highlight the need for improved HCV prevention strategies (including improved needle/syringe access and scale up of HCV therapy) for those at increased risk of HCV transmission in prison, including younger individuals.

Wastewater Analysis for Community-Wide Drugs Use Assessment

Wastewater-based epidemiology (WBE) complements existing epidemiology-based estimation techniques and provides objective, evidence-based estimates of illicit drug use. After consumption, biomarkers - drugs and their metabolites - excreted to toilets and flushed into urban sewer networks can be measured in raw wastewater samples. The quantified loads can serve as an estimate for the collective consumption of all people contributing to the wastewater sample. This transdisciplinary approach, further explained in this chapter, has developed, matured and is now established for monitoring substances such as cocaine and amphetamine-type stimulants. Research currently underway is refining WBE to new applications including new psychoactive substances (NPS).

Evaluation of in-sewer transformation of selected illicit drugs and pharmaceutical biomarkers

Wastewater-based epidemiology (WBE) is considered to be a useful tool for monitoring chemical consumption in the population. However, the lack of information on potential transformation of biomarkers in the sewer system can compromise the accuracy of the consumption estimation. The present study contributes to addressing this issue by investigating the in-sewer stability of biomarkers from a number of commonly used drugs using laboratory sewer reactors that can mimic different sewer conditions. A stable and an unstable chemical (carbamazepine and caffeine) were also used as benchmarking chemicals to reflect the chemical degradation potential in different sewer conditions. The results suggested that ketamine and norketamine were unstable in gravity and rising main sewers, ketamine was unstable in bulk liquid while norketamine was stable under the same condition. Similarly, mephedrone and methylone were unstable in sewer conditions with considerable deviation. Significant loss of buprenorphine, methadone, oxycodone and codeine was observed in the rising main sewer. Morphine and codeine glucuronide were found to be deconjugated from their glucuronides quickly in the presence of biofilms. This study indicates that it is important to evaluate the stability of biomarkers in the sewer system before using them in WBE for estimating consumption/exposure to reduce uncertainties.

Estimating heroin abuse in major Chinese cities through wastewater-based epidemiology

Heroin consumption in major cities across China was estimated for the first time via wastewater-based epidemiology. Influent and effluent wastewater samples were collected from 49 wastewater treatment plants (WWTPs) in 24 major cities that cover all the geographic regions of the country. Concentrations of morphine, 6-acetylmorphine, and codeine were measured. Near complete removal of morphine by wastewater treatment processes was observed, whereas removal rates of codeine were slightly lower. Morphine loads were much higher than codeine loads at most WWTPs in China, a trend opposite to that in many European countries. In addition, morphine and codeine loads were strongly correlated at most WWTPs, indicating morphine and codeine in wastewater were predominantly from the same source, street heroin. At WWTPs in Guangzhou and Shenzhen, codeine loads were considerably higher than morphine loads, consistent with previous reports of codeine abuse (e.g., as cough syrup) among middle and high school students in Guangdong province. Heroin consumption was derived based on morphine loads and taking into account therapeutic use of morphine and codeine, as well as contribution of codeine and acetylcodeine in street heroin. Highest heroin consumption was observed in northwestern and southwestern China. The average heroin consumption of the sampled cities was 64.6±78.7mg/1000inh/d. The nation-wide average heroin consumption was much lower than that of methamphetamine, consistent with seizure data and numbers of registered heroin and methamphetamine users in China.

Refining the excretion factors of methadone and codeine for wastewater analysis - Combining data from pharmacokinetic and wastewater studies

Analysing drug residues in wastewater (wastewater analysis) to monitor the consumption of those drugs in the population has become a complementary method to epidemiological surveys. In this method, the excretion factor of a drug (or the percentage of drug metabolites excreted through urine) is a critical parameter for the back-estimation of the consumption of a drug. However, this parameter is usually derived from a small database of human pharmacokinetic studies. This is true for methadone and codeine, the two most commonly used opioids and also common substances of abuse. Therefore, we aimed to refine the current excretion factors used for estimating methadone and codeine by analysing published data from the literature on the excretion of methadone, its main metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and codeine. Our review included both human drug pharmacokinetic studies and wastewater analysis studies. We found that while the commonly used excretion factor of methadone (~27.5%) was relatively accurate, the excretion factor of EDDP, a better biomarker for methadone consumption in sewer epidemiology, should be twice that of methadone (i.e. 55%) instead of the current equal or half values. For codeine, the excretion factor should be ~30% instead of 63.5% or 10% as previously used in wastewater analysis studies. Data from wastewater analysis studies could be used in this way to refine the excretion factors of the drugs of interest.