Stability of alcohol and tobacco consumption biomarkers in a real rising main sewer

Improved entropy-CRITIC population model based on temporal and spatial variability: Construction and application in wastewater epidemiology

Numerous factors contribute to the uncertainty inherent in conducting wastewater-based epidemiology (WBE), with shifting populations exerting a significant influence. However, traditional single- and multi-parameter population models suffer from certain limitations. This study employs an evaluation model framework to construct a model (EC model) based on data characteristics. Weight coefficients derived from 16 cities across seven regions of China are aggregated into a national model. In contrast to alternative models, the EC model exhibits a robust correlation (r2 = 0.98) with census population data, suggesting a potentially more precise depiction of population dynamics. The low variability (RSD = 9.73 %) indicates effective constraint of anomalous parameter fluctuations, yielding minimal Bias (-1.12 %) and SRMSE (14.75 %), thus ensuring reliable population estimation. The model is applied to estimate the consumption of lifestyle-related compounds and the prevalence of hypertension in China. Northern regions demonstrate higher consumption levels, alongside a significant disparity in hypertension prevalence (26.96 %) compared to the south (16.01 %). Hypertension exhibits positive correlations with lifestyle-related compounds such as alcohol and nicotine (r = 0.52, r = 0.55). Sensitivity analysis reveals that the EC model introduces an uncertainty of 24.48 % in population estimates. Through the incorporation of representative datasets and novel algorithms, this model has the potential to enhance the reliability of outcomes in WBE strategy implementation.

Development and validation of an imprinted polymer based DGT for monitoring β-blocker drugs in wastewater surveillance

Wastewater surveillance is an effective and objective approach to monitor contaminant releases and drug usage in the catchment, the estimation requires accurate measurement. In this study, a novel diffusive gradients in thin-film (DGT) technique based on molecularly imprinted polymers (MIPs) for selective measurement of a class of widely prescribed cardiovascular drugs (β-blockers) in wastewater was developed. The synthesized MIPs showed strong affinity and selectivity for the target compounds. The MIP-DGT had large effective capacities, its performance was independent of a wide range of environmental conditions, including pH (4.58 - 8.89), ionic strength (0.01 - 0.5 M) and dissolved organic matter (< 20 mg L-1). Biofouling had little effect on the uptake of target compounds within 7 days. MIP-DGT devices were applied in a Chinese urban WWTP alongside an auto-sampler. Metoprolol concentrations detected were much higher than other β-blockers. Concentrations obtained using MIP-DGT were comparable to the 24 h composite samples using an autosampler. The estimated daily consumption calculated based on the data obtained with MIP-DGT implied that metoprolol and propranolol were the most popular β-blockers in the studied area. Overall, the results in this study demonstrate that the MIP-DGT is a cost-effective, reliable and efficient tool for in situ wastewater monitoring.

Estimating alcohol and tobacco consumption of university students and urban population in Ho Chi Minh City by wastewater analysis

The quantitative measurement of urinary biomarkers in wastewater has emerged as a robust tool for estimating alcohol and tobacco consumption in populations. In this study, we applied the wastewater-based epidemiology (WBE) approach to compare alcohol and tobacco use between university students and urban inhabitants in Ho Chi Minh City, Vietnam. Ethyl sulfate and cotinine serve as markers for alcohol and tobacco use, respectively. Our findings reveal that urban inhabitants aged 15 and above consume 1.56 ± 0.23 mL of pure ethanol and 2.8 ± 0.33 mg of nicotine per day, while university students consume 0.69 ± 0.13 mL of pure alcohol and 1.2 ± 0.2 mg of nicotine per day. This indicates that, on average, students consume less alcohol and tobacco compared with urban adults. A Monte Carlo simulation indicated that, on average, university students in our study smoke 1.5 cigarettes per day, while urban residents aged 15 and above smoke 4.3 cigarettes per day. Considering the smoking prevalence, a student smoker in this study consumes 6.5 cigarettes per day, a level high enough to establish addiction. On the other hand, alcohol use estimation is significantly lower than previous survey-based reports, likely due to degradation within on-site septic tanks. Future research should aim to extend the sampling period to capture seasonal variations and improve the understanding of tobacco and alcohol consumption patterns. The results from this study are crucial for decision-makers in Ho Chi Minh City to develop effective public health strategies and interventions. PRACTITIONER POINTS: Wastewater-based approach is applicable to estimate the tobacco consumption in Ho Chi Minh City. Each current smoker in the urban area of Ho Chi Minh City smokes nearly a package a day. The estimated consumption for student smokers in U-town is 6.5 cigarettes per day, a level high enough to establish addiction. The existence of septic tanks within Vietnam's drainage systems prevents reliable estimation of alcohol consumption for the entire population.

A Bayesian framework for modeling COVID-19 case numbers through longitudinal monitoring of SARS-CoV-2 RNA in wastewater

Wastewater-based surveillance has become an important tool for research groups and public health agencies investigating and monitoring the COVID-19 pandemic and other public health emergencies including other pathogens and drug abuse. While there is an emerging body of evidence exploring the possibility of predicting COVID-19 infections from wastewater signals, there remain significant challenges for statistical modeling. Longitudinal observations of viral copies in municipal wastewater can be influenced by noisy datasets and missing values with irregular and sparse samplings. We propose an integrative Bayesian framework to predict daily positive cases from weekly wastewater observations with missing values via functional data analysis techniques. In a unified procedure, the proposed analysis models severe acute respiratory syndrome coronavirus-2 RNA wastewater signals as a realization of a smooth process with error and combines the smooth process with COVID-19 cases to evaluate the prediction of positive cases. We demonstrate that the proposed framework can achieve these objectives with high predictive accuracies through simulated and observed real data.

In-sewer stability assessment of 140 pharmaceuticals, personal care products, pesticides and their metabolites: Implications for wastewater-based epidemiology biomarker screening

The monitoring of pharmaceuticals, personal care products (PCPs), pesticides, and their metabolites through wastewater-based epidemiology (WBE) provides timely information on pharmaceutical consumption patterns, chronic disease treatment rates, antibiotic usage, and exposure to harmful chemicals. However, before applying them for quantitative WBE back-estimation, it is necessary to understand their stability in the sewer system to screen suitable WBE biomarkers thereby reducing research uncertainty. This study investigated the in-sewer stability of 140 typical pharmaceuticals, PCPs, pesticides, and their metabolites across 15 subcategories, using a series of laboratory sewer sediment and biofilm reactors. For the first time, stability results for 89 of these compounds were reported. Among the 140 target compounds, 61 biomarkers demonstrated high stability in all sewer reactors, while 41 biomarkers were significantly removed merely by sediment processes. For biomarkers exhibiting notable attenuation, the influence of sediment processes was generally more pronounced than biofilm, due to its stronger microbial activities and more pronounced diffusion or adsorption processes. Adsorption emerged as the predominant factor causing biomarker removal compared to biodegradation and diffusion. Significantly different organic carbon-water partitioning coefficient (Koc) and distribution coefficient at pH = 7 (logD) values were observed between highly stable and unstable biomarkers, with most hydrophobic substances (Koc > 100 or logD > 2) displaying instability. In light of these findings, we introduced a primary biomarker screening process to efficiently exclude inappropriate candidates, achieving a commendable 77 % accuracy. Overall, this study represents the first comprehensive report on the in-sewer stability of 89 pharmaceuticals, PCPs, pesticides, and their metabolites, and provided crucial reference points for understanding the intricate sewer sediment processes.

Investigating alcohol consumption in China via wastewater-based epidemiology

Alcohol abuse and addiction is a public health issue of global concern. Wastewater-based epidemiology (WBE) is a forceful and effective complementary tool for investigating chemical consumption. This study examined alcohol consumption in major cities of China via WBE and compared WBE estimates with other data sources. A simple and valid ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of two alcohol metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS) in wastewater. The optimized method was applied to 62 sewage samples collected from wastewater treatment plants (WWTPs) in 31 provincial capital cities across China in the fourth quarter of 2020. The methodology established in this study was validated with the lower limit of quantification (LLOQ) up to 0.1 μg/L, good linearity in the range of 0.1-50 μg/L, intra-day and inter-day precision less than 5.58% and 5.55%, respectively, and the recoveries of the extracts were higher than 97.14%. The consumption range of alcohol estimated via WBE was 6.09 ± 4.56 ethanol/person/day (EPD) in the capital cities of China. Alcohol consumption varies significantly between cities in China, with WBE estimating lower alcohol consumption than WHO and lower than foreign countries. Investing in alcohol consumption based on WBE has great potential to accurately and efficiently estimate alcohol consumption.

Assessing the effects of COVID-19 restrictions on alcohol consumption in Melbourne, Australia using high-resolution wastewater sampling

The impact of the COVID-19 pandemic and related restrictions on alcohol consumption in Australia remains unclear. High-resolution daily samples from a wastewater treatment plant (WWTP) which served one of the largest cities in Australia, Melbourne, were analysed for temporal trends in alcohol consumption under extended periods of COVID-19 restrictions in 2020. Melbourne experienced two major lockdowns in 2020, which divided the year of 2020 into five periods (pre-lockdown, first lockdown, between lockdown, second lockdown and post second-lockdown). In this study, daily sampling identified shifts in alcohol consumption during different periods of restrictions. Alcohol consumption in the first lockdown period, when bars closed and social and sports events ceased, was lower than pre-lockdown period. However, alcohol consumption was higher in the second lockdown period than the previous lockdown period. There were spikes in alcohol consumption at the start and end of each lockdown (except for post lockdown). For most of 2020, the usual weekday-weekend variations in alcohol consumption were less evident but there was a significant difference in alcohol consumption between weekdays and weekends after the second lockdown. This suggests that drinking patterns eventually returned to normal after the end of the second lockdown. This study demonstrates the usefulness of high-resolution wastewater sampling in evaluating the effects on alcohol consumption of social interventions in specific temporal locations.

Understanding common population markers for SARS-CoV-2 RNA normalization in wastewater - A review

Wastewater monitoring and epidemiology have seen renewed interest during the recent COVID-19 pandemic. As a result, there is an increasing need to normalize wastewater-derived viral loads in local populations. Chemical tracers, both exogenous and endogenous compounds, have proven to be more stable and reliable for normalization than biological indicators. However, differing instrumentation and extraction methods can make it difficult to compare results. This review examines current extraction and quantification methods for ten common population indicators: creatinine, coprostanol, nicotine, cotinine, sucralose, acesulfame, androstenedione 5-hydroindoleacetic acid (5-HIAA), caffeine, and 1,7-dimethyluric acid. Some wastewater parameters such as ammonia, total nitrogen, total phosphorus, and daily flowrate were also evaluated. The analytical methods included direct injection, dilute and shoot, liquid/liquid, and solid phase extraction (SPE). Creatine, acesulfame, nicotine, 5-HIAA and androstenedione have been analysed by direct injection into LC-MS; however, most authors prefer to include SPE steps to avoid matrix effects. Both LC-MS and GC-MS have been successfully used to quantify coprostanol in wastewater, and the other selected indicators have been quantified successfully with LC-MS. Acidification to stabilize the sample before freezing to maintain the integrity of samples has been reported to be beneficial. However, there are arguments both for and against working at acidic pHs. Wastewater parameters mentioned earlier are quick and easy to quantify, but the data does not always represent the human population effectively. A preference for population indicators originating solely from humans is apparent. This review summarises methods employed for chemical indicators in wastewater, provides a basis for choosing an appropriate extraction and analysis method, and highlights the utility of accurate chemical tracer data for wastewater-based epidemiology.

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.

Effects of sewer biofilms on the degradability of carbapenems in wastewater using laboratory scale bioreactors

Carbapenems are last-resort antibiotics used to treat bacterial infections unsuccessfully treated by most common categories of antibiotics in humans. Most of their dosage is secreted unchanged as waste, thereby making its way into the urban water system. There are two major knowledge gaps addressed in this study to gain a better understanding of the effects of their residual concentrations on the environment and environmental microbiome: development of a UHPLC-MS/MS method of detection and quantification from raw domestic wastewater via direct injection and study of their stability in sewer environment during the transportation from domestic sewers to wastewater treatment plants. The UHPLC-MS/MS method was developed for four carbapenems: meropenem, doripenem, biapenem and ertapenem, and validation was performed in the range of 0.5-10 μg/L for all analytes, with limit of detection (LOD) and limit of quantification (LOQ) values ranging from 0.2-0.5 μg/L and 0.8-1.6 μg/L respectively. Laboratory scale rising main (RM) and gravity sewer (GS) bioreactors were employed to culture mature biofilms with real wastewater as the feed. Batch tests were conducted in RM and GS sewer bioreactors fed with carbapenem-spiked wastewater to evaluate the stability of carbapenems and compared against those in a control reactor (CTL) without sewer biofilms, over a duration of 12 h. Significantly higher degradation was observed for all carbapenems in RM and GS reactors (60 - 80%) as opposed to CTL reactor (5 - 15%), which indicates that sewer biofilms play a significant role in the degradation. First order kinetics model was applied to the concentration data along with Friedman's test and Dunn's multiple comparisons analysis to establish degradation patterns and differences in the degradation observed in sewer reactors. As per Friedman's test, there was a statistically significant difference in the degradation of carbapenems observed depending on the reactor type (p = 0.0017 - 0.0289). The results from Dunn's test indicate that the degradation in the CTL reactor was statistically different from that observed in either RM (p = 0.0033 - 0.1088) or GS (p = 0.0162 - 0.1088), with the latter two showing insignificant difference in the degradation rates observed (p = 0.2850 - 0.5930). The findings contribute to the understanding about the fate of carbapenems in urban wastewater and the potential application of wastewater-based epidemiology.

Illicit drugs and their metabolites in urban wastewater: Analysis, occurrence and consumption in Xinjiang, China

The use of illicit drugs has increased considerably across the world. Wastewater-based epidemiology (WBE) of illicit drugs might help determine the types and quantity of illicit drugs consumed in a region. In this study, WBE was applied to analyze illicit drugs in five representative urban wastewater treatment plants (WWTPs) in Xinjiang, China. The collected samples were pretreated under optimized solid-phase extraction conditions and then analyzed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results revealed the presence of 9 of the 11 evaluated drugs; among them, the concentrations of these substances ranged as follows: METH (2.60-10.02 ng/L), MDMA (0.49-6.87 ng/L), MOR (4.53-44.75 ng/L), COD (2.24-8.30 ng/L), MTD (1.36-3.75 ng/L), COC (0.48 ng/L), THC (5.98-18.89 ng/L), BE (1.12-2.45 ng/L) and KET (1.50 ng/L). And an estimate of the per capita consumption revealed morphine (10.2 mg/d/1000inhabitants), cannabis (3.9 mg/d/1000inhabitants), 3,4-methylenedioxymethamphetamine (3.9 mg/d/1000 inhabitants), and methamphetamine (2.2 mg/d/1000 inhabitants) as the main substances of abuse in Xinjiang, China. The results of this study might be taken as a reference for future studies on the continuous monitoring of such drugs.

Consumption of common illicit drugs in twenty-one cities in southwest China through wastewater analysis

Wastewater-based epidemiology (WBE) was applied to estimate illicit drugs consumption at a provincial scale in southwest China. A large-scale wastewater sampling campaign was carried out from October to November in 2021 in 156 different wastewater treatment plants (WWTPs). Two 24-h composite influent wastewater samples were collected in each WWTP. Concentrations of 11 illicit drugs or their metabolites were determined using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Benzoylecgonine, cocaine, 6-monoacetylmorphine, norketamine, 3,4-methylenedioxymethamphetamine (MDMA), and MDA were not detected in any of the wastewater samples. Methamphetamine and morphine were detected in >84% of samples, while ketamine was found in about 6% of the samples. The city-specific population-weighted consumption of methamphetamine and ketamine were in the range of 0.6-49.7 and N.D.-7.0 mg 1000 inh^-1 day^-1, respectively, with provincial population-weighted values of 22.6 and 2.4 mg 1000 inh^-1 day^-1 in southwest China. The city-specific load of morphine varied from 3.2 to 10.2 mg 1000 inh^-1 day^-1, with provincial population-weighted load of 6.7 mg 1000 inh^-1 day^-1. Taking into account therapeutic use of morphine and codeine, the provincial heroin consumption was estimated to be 10.3 mg 1000 inh^-1 day^-1, ranging from 1.7 to 18.5 mg 1000 inh^-1 day^-1 in 21 cities. Overall, the patterns of illicit drugs use were similar across southwest China, with high prevalence of methamphetamine and heroin, but relatively low use of ketamine. These findings could provide accurate drugs consumption information for timely identifying potential hotspots of illicit drugs use in southwest China.

Evaluating the impact of COVID-19 countermeasures on alcohol consumption through wastewater-based epidemiology: A case study in Belgium

Wastewater-based epidemiology (WBE) is a complementary approach to monitor alcohol consumption in the general population. This method measures concentrations of xenobiotic biomarkers (e.g., ethyl sulphate) in influent wastewater (IWW) and converts these to population-normalized mass loads (PNML, in g/day/1000 inhabitants) by multiplying with the flow rate and dividing by the catchment population. The aims of this case study were to: (i) investigate temporal trends in alcohol use during the COVID-19 pandemic; and (ii) measure the effect of policy measures on alcohol consumption. Daily 24-h composite IWW samples (n = 735) were collected in the wastewater treatment plant of the university city of Leuven (Belgium) starting from September 2019 to September 2021. This is the first study that investigates alcohol use through WBE for a continuous period of two years on a daily basis. Mobile phone data was used to accurately capture population fluxes in the catchment area. Data was evaluated using a time series based statistical framework to graphically and quantitatively assess temporal differences in the measured PNML. Different WBE studies observed temporal changes in alcohol use during the COVID-19 pandemic. In this study, the PNML of ethyl sulphate decreased during the first lockdown phase, potentially indicating that less alcohol was consumed at the Leuven area during home confinement. Contrastingly, alcohol use increased after the re-opening of the catering industry. Additionally, a decrease in alcohol use was observed during the exam periods at the University of Leuven and an increase during the holiday periods. The present study shows the potential of WBE to rapidly assess the impact of some policy measures on alcohol consumption in Belgium. This study also indicates that WBE could be employed as a complementary data source to fill in some of the current knowledge gaps linked to lifestyle behavior.

Assessing changes in nicotine consumption over two years in a population of Hanoi by wastewater analysis with benchmarking biomarkers

Monitoring the actual change in consumption of nicotine (a proxy for smoking) in the population is essential for formulating tobacco control policies. In recent years, wastewater-based epidemiology (WBE) has been applied as an alternative method to estimate changes in consumption of tobacco and other substances in different communities around the world, with high potential to be used in resource-scarce settings. This study aimed to conduct a WBE analysis in Hanoi, Vietnam, a lower-middle-income-country setting known for high smoking prevalence. Wastewater samples were collected at two sites along a sewage canal in Hanoi during three periods: Period 1 (September 2018), Period 2 (December 2018-January 2019), and Period 3 (December 2019-January 2020). Concentrations of cotinine, 3-hydroxycotinine, and nicotine ranged from 0.73 μg/L to 3.83 μg/L, from 1.09 μg/L to 5.07 μg/L, and from 0.97 μg/L to 9.90 μg/L, respectively. The average mass load of cotinine estimated for our samples was 0.45 ± 0.09 mg/day/person, which corresponds to an estimated daily nicotine consumption of 1.28 ± 0.25 mg/day/person. No weekly trend was detected over the three monitoring periods. We found the amount of nicotine consumption in Period 1 to be significantly lower than in Period 2 and Period 3. Our WBE estimates of smoking prevalence were slightly lower than the survey data. The analysis of benchmarking biomarkers confirmed that cotinine was stable in the samples similar to acesulfame, while paracetamol degraded along the sewer canal. Further refinement of the WBE approach may be required to improve the accuracy of analyzing tobacco consumption in the poor sewage infrastructure setting of Vietnam.

Towards a novel application of wastewater-based epidemiology in population-wide assessment of exposure to volatile organic compounds

In this study, we investigated the feasibility of detecting 35 urinary biomarkers of volatile organic compounds (VOCs) exposure in community wastewater. 24-h composited municipal wastewater samples were collected from two communities (n = 8) in the southeastern US. Using isotope-dilution liquid chromatography-tandem mass spectrometry, results showed 16 metabolites were detected in wastewater samples, including indicators of exposure to acrolein, acrylonitrile, 1,3-butadiene, crotonaldehyde, n,n-dimethylformamide (DMF), ethylbenzene, nicotine, propylene oxide, styrene, tetrachloroethylene, toluene, and xylene. Additional metabolites qualitatively identified exposure to acrylamide and trichloroethylene. Community 1 (closer proximity to manufacturing facilities) had a greater number of detects (n = 36) and higher VOC loadings, 22,000 mg day^-1 per 1000 people, as compared to Community 2 (n = 28), 7100 mg day^-1 per 1000 people. Normalizing to nicotine consumption biomarkers to account for differences in smoking behaviors, Community 1 continued to have higher levels of propylene oxide, crotonaldehyde, DMF, and acrylonitrile exposures, VOCs generally sourced from manufacturing activities and vehicle emissions. This is the first study to utilize wastewater to detect urinary biomarkers of VOCs exposure. These preliminary results suggest the WBE approach as a potentially powerful tool to assess community health exposures to indoor and outdoor air pollutants.

The role of the sewer system in estimating urban emissions of chemicals of emerging concern

The use of chemicals by society has resulted in calls for more effective control of their emissions. Many of these chemicals are poorly characterized because of lacking data on their use, environmental fate and toxicity, as well as lacking detection techniques. These compounds are sometimes referred to as contaminants of emerging concern (CECs). Urban areas are an important source of CECs, where these are typically first collected in sewer systems and then discharged into the environment after being treated in a wastewater treatment plant. A combination of emission estimation techniques and environmental fate models can support the early identification and management of CEC-related environmental problems. However, scientific insight in the processes driving the fate of CECs in sewer systems is limited and scattered. Biotransformation, sorption and ion-trapping can decrease CEC loads, whereas enzymatic deconjugation of conjugated metabolites can increase CEC loads as metabolites are back-transformed into their parent respective compounds. These fate processes need to be considered when estimating CEC emissions. This literature review collates the fragmented knowledge and data on in-sewer fate of CECs to develop practical guidelines for water managers on how to deal with in-sewer fate of CECs and highlights future research needs. It was assessed to what extent empirical data is in-line with text-book knowledge and integrated sewer modelling approaches. Experimental half-lives (n = 277) of 96 organic CECs were collected from literature. The findings of this literature review can be used to support environmental modelling efforts and to optimize monitoring campaigns, including field studies in the context of wastewater-based epidemiology.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11157-022-09638-9.

Population Health Metrics During the Early Stages of the COVID-19 Pandemic: Correlative Pilot Study

BACKGROUND

COVID-19 has caused nearly 1 million deaths in the United States, not to mention job losses, business and school closures, stay-at-home orders, and mask mandates. Many people have suffered increased anxiety and depression since the pandemic began. Not only have mental health symptoms become more prevalent, but alcohol consumption has also increased during this time. Helplines offer important insight into both physical and mental wellness of a population by offering immediate, anonymous, cheap, and accessible resources for health and substance use disorders (SUD) that was unobstructed by many of the mandates of the pandemic. Further, the pandemic also launched the use of wastewater surveillance, which has the potential for tracking not only population infections but also consumption of substances such as alcohol.

OBJECTIVE

This study assessed the feasibility of using multiple public surveillance metrics, such as helpline calls, COVID-19 cases, and alcohol metabolites in wastewater, to better understand the need for interventions or public health programs in the time of a public health emergency.

METHODS

Ethanol metabolites were analyzed from wastewater collected twice weekly from September 29 to December 4, 2020, in a Midwestern state. Calls made to the helpline regarding housing, health care, and mental health/SUD were correlated with ethanol metabolites analyzed from wastewater samples, as well as the number of COVID-19 cases during the sampling period.

RESULTS

Correlations were observed between COVID-19 cases and helpline calls regarding housing and health care needs. No correlation was observed between the number of COVID-19 cases and mental health/SUD calls. COVID-19 cases on Tuesdays were correlated with the alcohol metabolite ethyl glucuronide (EtG). Finally, EtG levels were negatively associated with mental health/SUD helpline calls.

CONCLUSIONS

Although helpline calls provided critical services for health care and housing-related concerns early in the pandemic, evidence suggests helpline calls for mental health/SUD-related concerns were unrelated to COVID-19 metrics. Instead, COVID metrics were associated with alcohol metabolites in wastewater. Although this research was formative, with continued and expanded monitoring of population metrics, such as helpline usage, COVID-19 metrics, and wastewater, strategies can be implemented to create precision programs to address the needs of the population.

Long-term monitoring of drug consumption patterns during the COVID-19 pandemic in a small-sized community in Brazil through wastewater-based epidemiology

The abuse of legal and illegal drugs is a global public health problem, also affecting the social and economic well-being of the population. Thus, there is a significant interest in monitoring drug consumption. Relevant epidemiological information on lifestyle habits can be obtained from the chemical analysis of urban wastewater. In this work, passive sampling using polar organic chemical integrative samplers (POCIS) was used to quantify licit and illicit drugs biomarkers in wastewater for the application of wastewater-based epidemiology (WBE). In this WBE study, a small urban community of approximately 1179 inhabitants was monitored from 18 March 2020 to 3 March 2021, covering the mobility restriction and flexibilization periods of the COVID-19 pandemic in Brazil. Consumption was estimated for amphetamine, caffeine, cocaine, MDMA, methamphetamine, nicotine, and THC. The highest estimated consumption among illicit drugs was for THC (2369 ± 1037 mg day-1 1000 inh-1) followed by cocaine (353 ± 192 mg day-1 1000 inh-1). There was a negative correlation between consumption of caffeine, cocaine, MDMA, nicotine, and THC with human mobility, expressed by cellular phone mobility reports (P-value = 0.0094, 0.0019, 0.0080, 0.0009, and 0.0133, respectively). Our study is the first long-term drug consumption evaluation during the COVID-19 pandemic, with continuous sampling for almost a whole year. The observed reduction in consumption of both licit and illicit drugs is probably associated with stay-at-home orders and reduced access, which can be due to the closure of commercial facilities during some time of the evaluated period, smaller drug supply, and reduced income of the population due to the shutdown of companies and unemployment. The assay described in this study can be used as a complementary and cost-effective tool to the long-term monitoring of drug use biomarkers in wastewater, a relevant epidemiological strategy currently limited to short collection times.

Assessment of correlations between sildenafil use and comorbidities and lifestyle factors using wastewater-based epidemiology

Sildenafil (SIL) is widely used to treat erectile dysfunction. Information on its consumption and the factors influencing its use is limited in China. In this study, we sampled composite influent wastewater samples from 33 Chinese cities and analyzed SIL using liquid chromatography-tandem mass spectrometry. SIL consumption was estimated using wastewater-based epidemiology (WBE) and ranged from 10.6 mg/d/1000 people to 132 mg/d/1000 people, with a mean of 53 mg/d/1000 people. Prescription sales (3570 kg) accounted for 13.3% of the estimated SIL use (26842 kg) in 2018, thereby implying that SIL illicit use was greater than prescription use in China. Some regional differences were observed in SIL use, which was significantly higher in North China than South China (p < 0.05), thereby reflecting that the prevalence of SIL was affected by differences in lifestyle and socioeconomic factors. We found significant positive correlations between SIL use and consumption of allopurinol, hydrochlorothiazide, nicotine, and alcohol, thereby suggesting that the prevalence of SIL was associated with the prevalence of gout, hypertension, smoking, and drinking. Moreover, age structures, internet use, and marriage rates were positively correlated with SIL use, whereas the unemployment rate was negatively correlated with SIL use. Our study demonstrates that WBE is valuable for medical research to investigate licit and illicit drug use and to assess the underlying associations of different chemical uses.

Artificial neural network-based estimation of COVID-19 case numbers and effective reproduction rate using wastewater-based epidemiology

As a cost-effective and objective population-wide surveillance tool, wastewater-based epidemiology (WBE) has been widely implemented worldwide to monitor the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA concentration in wastewater. However, viral concentrations or loads in wastewater often correlate poorly with clinical case numbers. To date, there is no reliable method to back-estimate the coronavirus disease 2019 (COVID-19) case numbers from SARS-CoV-2 concentrations in wastewater. This greatly limits WBE in achieving its full potential in monitoring the unfolding pandemic. The exponentially growing SARS-CoV-2 WBE dataset, on the other hand, offers an opportunity to develop data-driven models for the estimation of COVID-19 case numbers (both incidence and prevalence) and transmission dynamics (effective reproduction rate). This study developed artificial neural network (ANN) models by innovatively expanding a conventional WBE dataset to include catchment, weather, clinical testing coverage and vaccination rate. The ANN models were trained and evaluated with a comprehensive state-wide wastewater monitoring dataset from Utah, USA during May 2020 to December 2021. In diverse sewer catchments, ANN models were found to accurately estimate the COVID-19 prevalence and incidence rates, with excellent precision for prevalence rates. Also, an ANN model was developed to estimate the effective reproduction number from both wastewater data and other pertinent factors affecting viral transmission and pandemic dynamics. The established ANN model was successfully validated for its transferability to other states or countries using the WBE dataset from Wisconsin, USA.

Enhanced decay of coronaviruses in sewers with domestic wastewater

Recent outbreaks caused by coronaviruses and their supposed potential fecal-oral transmission highlight the need for understanding the survival of infectious coronavirus in domestic sewers. To date, the survivability and decay of coronaviruses were predominately studied using small volumes of wastewater (normally 5-30 mL) in vials (in-vial tests). However, real sewers are more complicated than bulk wastewater (wastewater matrix only), in particular the presence of sewer biofilms and different operational conditions. This study investigated the decay of infectious human coronavirus 229E (HCoV-229E) and feline infectious peritonitis virus (FIPV), two typical surrogate coronaviruses, in laboratory-scale reactors mimicking the gravity (GS, gravity-driven sewers) and rising main sewers (RM, pressurized sewers) with and without sewer biofilms. The in-sewer decay of both coronaviruses was greatly enhanced in comparison to those reported in bulk wastewater through in-vial tests. 99% of HCoV-229E and FIPV decayed within 2 h under either GS or RM conditions with biofilms, in contrast to 6-10 h without biofilms. There is limited difference in the decay of HCoV and FIPV in reactors operated as RM or GS, with the T90 and T99 difference of 7-10 min and 14-20 min, respectively. The decay of both coronaviruses in sewer biofilm reactors can be simulated by biphasic first-order kinetic models, with the first-order rate constant 2-4 times higher during the first phase than the second phase. The decay of infectious HCoV and FIPV was significantly faster in the reactors with sewer biofilms than in the reactors without biofilms, suggesting an enhanced decay of these surrogate viruses due to the presence of biofilms and related processes. The mechanism of biofilms in virus adsorption and potential inactivation remains unclear and requires future investigations. The results indicate that the survivability of infectious coronaviruses detected using bulk wastewater overestimated the infectivity risk of coronavirus during wastewater transportations in sewers or the downstream treatment.

Comparison of tobacco use in a university town and a nearby urban area in China by intensive analysis of wastewater over one year period

Understanding smoking patterns in the population is essential for formulating public health and tobacco control policies. Wastewater-based epidemiology (WBE) is a valuable complementary approach to conventional survey methods to measure tobacco use, providing non-invasive information in an objective and cost-effective manner. This study estimates tobacco use in an urban population at daily resolution and in a university town at weekly resolution in China. Wastewater samples were collected daily in an urban catchment (n = 279) and every week from a university town located within 13 km of the urban catchment (n = 43) in 2017-2018. The tobacco-related biomarkers, cotinine and hydroxycotinine, and nicotine were analyzed via direct injection liquid chromatography tandem mass spectrometry (LC-MS/MS). Per capita daily tobacco use was back-estimated based on cotinine in wastewater. Over the year of sampling, we observed an increasing trend in tobacco use in the urban catchment that corroborated with sales statistics in 2017-2018. Tobacco use in the urban area was estimated to be 1.16 cigarettes/person aged 15+/day, while it was estimated to be 0.60 cigarettes/person aged 15+/day in the university town. The level of tobacco use in the university town remained stable over the year in contrast to the urban area. The difference of tobacco use in the two catchments may be attributed to their demographic differences. Furthermore, the Tobacco-Free Campus Policy would be a possible reason for the lower level of tobacco use in the university town.

Water quality modeling in sewer networks: Review and future research directions

Urban sewer networks (SNs) are increasingly facing water quality issues as a result of many challenges, such as population growth, urbanization and climate change. A promising way to addressing these issues is by developing and using water quality models. Many of these models have been developed in recent years to facilitate the management of SNs. Given the proliferation of different water quality models and the promise they have shown, it is timely to assess the state-of-the-art in this field, to identify potential challenges and suggest future research directions. In this review, model types, modeled quality parameters, modeling purpose, data availability, type of case studies and model performance evaluation are critically analyzed and discussed based on a review of 110 papers published between 2010 and 2019. The review identified that applications of empirical and kinetic models dominate those of data-driven models for addressing water quality issues. The majority of models are developed for prediction and process understanding using experimental or field sampled data. While many models have been applied to real problems, the corresponding prediction accuracies are overall moderate or, in some cases, low, especially when dealing with larger SNs. The review also identified the most common issues associated with water quality modeling of SNs and based on these proposed several future research directions. These include the identification of appropriate data resolutions for the development of different SN models, the need and opportunity to develop hybrid SN models and the improvement of SN model transferability.

Cotinine Hydroxylase CotA Initiates Biodegradation of Wastewater Micropollutant Cotinine in Nocardioides sp. Strain JQ2195

Cotinine is a stable toxic contaminant, produced as a by-product of smoking. It is of emerging concern due to its global distribution in aquatic environments. Microorganisms have the potential to degrade cotinine; however, the genetic mechanisms of this process are unknown. Nocardioides sp. strain JQ2195 is a pure-culture strain that has been reported to degrade cotinine at micropollutant concentrations. This strain utilizes cotinine as its sole carbon and nitrogen source. In this study, a 50-kb gene cluster (designated cot), involved in cotinine degradation, was predicted based on genomic and transcriptomic analyses. A novel three-component cotinine hydroxylase gene (designated cotA1A2A3), which initiated cotinine catabolism, was identified and characterized. CotA from Shinella sp. strain HZN7 was heterologously expressed and purified and was shown to convert cotinine into 6-hydroxycotinine. H₂¹⁸O-labeling and electrospray ionization-mass spectrometry (ESI-MS) analysis confirmed that the hydroxyl group incorporated into 6-hydroxycotinine was derived from water. This study provides new molecular insights into the microbial metabolism of heterocyclic chemical pollutants. IMPORTANCE In the human body, cotinine is the major metabolite of nicotine, and 10 to 15% of generated cotinine is excreted in urine. Cotinine is a structural analogue of nicotine and is much more stable than nicotine. Increased tobacco consumption has led to high environmental concentrations of cotinine, which may have detrimental effects on aquatic ecosystems and human health. Nocardioides sp. strain JQ2195 is a unique cotinine-degrading bacterium. However, the underlying genetic and biochemical foundations of cotinine degradation are still unknown. In this study, a 50-kb gene cluster (designated cot) was identified by genomic and transcriptomic analyses as being involved in the degradation of cotinine. A novel three-component cotinine hydroxylase gene (designated cotA1A2A3) catalyzed cotinine to 6-hydroxy-cotinine. This study provides new molecular insights into the microbial degradation and enzymatic transformation of cotinine.

Application of wastewater-based epidemiology to investigate stimulant drug, alcohol and tobacco use in Lithuanian communities

WBE was applied to evaluate illicit drug (i.e. amphetamine, cocaine, MDMA and methamphetamine), alcohol and tobacco use in three Lithuanian cities in 2018 and 2019. Considerable concentrations of methamphetamine and MDMA were found in the three locations, suggesting a specific Lithuanian consumption pattern. Yet, unexpected high concentrations of amphetamine (>4 μg/L) were detected in two samples of Kaunas in 2018. Through the use of chiral analysis and non-target and suspect drug precursor compound screening, these extreme values were confirmed to be the result of direct disposal of amphetamine in the sewers. Furthermore, substantial alcohol use was measured in the three investigated catchment populations of Lithuania with almost 4 standard drinks/day/inhabitant aged 15+ on average in 2019. For tobacco, an average of 5.6 cigarettes/day/inhabitant aged 15+ in 2019 was reported with large discrepancies between WBE figures and sales data, potentially highlighting illegal trade of tobacco products.

Effects of pH, Temperature, Suspended Solids, and Biological Activity on Transformation of Illicit Drug and Pharmaceutical Biomarkers in Sewers

In-sewer stability of biomarkers is a critical factor for wastewater-based epidemiology, as it could affect the accuracy of the estimated prevalence of substances in the community. The spatiotemporal variations of environmental and biological conditions in sewers can influence the transformation of biomarkers. To date, the relationship between environmental variables and biomarker stability in sewers is poorly understood. Therefore, this study evaluated the transformation of common illicit drug and pharmaceutical biomarkers in laboratory sewer reactors with different levels of pH, temperature, and suspended solids. The correlations between degradation rates of 14 biomarkers, 3 controlled environmental variables (pH, temperature, and suspended solids concentration), and 3 biological activity indicators (sulfide production rate, methane production rate, and the removal rate of soluble chemical oxygen demand (SCOD)) were assessed using correlation matrix, stepwise regression method, and principal component analysis. The consistent results affirmed the dominant effects of biological activities and pH on biomarker transformation in sewers, particularly for labile compounds, whereas the impact of temperature or suspended solids was less significant. This study enhances the understanding of factors affecting the fate of micropollutants in sewer systems and facilitates the interpretation of WBE results for assessing drug use and public health in communities.

Using Prescription and Wastewater Data to Estimate the Correction Factors of Atenolol, Carbamazepine, and Naproxen for Wastewater-Based Epidemiology Applications

The correction factor (CF) is a critical parameter in wastewater-based epidemiology (WBE) that significantly influences the accuracy of the final consumption estimates. However, most CFs have been derived from a few old pharmacokinetic studies and should be re-evaluated and refined to improve the accuracy of the WBE approach. This study aimed to review and estimate the CFs for atenolol, carbamazepine, and naproxen for WBE using the daily mass loads of those pharmaceuticals in wastewater and their corresponding dispensed prescription data in Australia. Influent wastewater samples were collected from wastewater treatment plants serving approximately 24% of the Australian population and annual national dispensed prescription data. The estimated CFs for atenolol and carbamazepine are 1.37 (95% CI: 1.17-1.66) and 8.69 (95% CI: 7.66-10.03), respectively. Due to significant over-the-counter sales of naproxen, a reliable CF could not be estimated based on prescription statistics. Using an independent dataset of 186 and 149 wastewater samples collected in an urban catchment in 2011 and 2012, WBE results calculated using the new CFs matched well with the dispensed data for atenolol and carbamazepine in the catchment area.

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.

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.

Transformation of phthalates and their metabolites in wastewater under different sewer conditions

There is an increasing demand to monitor the human exposure to phthalates, and a few studies have used phthalate metabolites in wastewater to estimate exposure to these chemicals in the population. However, it is suspected that the stability of phthalates and phthalate metabolites during sewer transport can influence the final estimates. In this study, we used laboratory sewer reactors to evaluate the in-sewer transformation of phthalates and their metabolites, and deconjugation of phthalate metabolites. We found concentrations of parent phthalates decreased quickly over time while the concentrations of phthalate metabolites increased significantly for most compounds, indicating that parent phthalate compounds are partly transformed into their metabolites in the sewer. Our assessment of the deconjugation of glucuronide-conjugated phthalate metabolites found that this process did not significantly affect the concentrations of phthalate metabolites in the wastewater, with the relative difference ranging from -16% to 7% between enzymatically treated samples and control group. Additionally, our results showed that phthalate metabolites could be subject to rapid degradation during the incubation process. Our findings suggested that the level of phthalate metabolites in sewage could be strongly influenced by the in-sewer transformation of the parent phthalates and of themselves, and could not be assumed as uniquely the results of urinary excretion after human exposure to parent phthalates.

Evaluating the stability of prescription drugs in municipal wastewater and sewers based on wastewater-based epidemiology

Wastewater-based epidemiology (WBE) is considered as an effective tool for monitoring drug consumption, which is often obtained by back-calculation using the influent concentration and other parameters of wastewater treatment plants. Lack of information on the transformation of drugs in municipal wastewater and sewers may lead to inaccurate consumption estimation. Fourteen prescription drugs in four major categories of diseases (cardiovascular, diabetes, depression, and asthma) were selected to study their adsorption and biodegradation in wastewater and biofilm sewers under different temperatures, pH and biofilms conditions. The result demonstrated that the decay percentage of drugs in wastewater is increased with temperature. Within 72 h, eleven of these 14 drugs, such as metformin, metoprolol, bezafibrate, etc., have decay percentages below 20% in wastewater, which are considered as stable drugs; and the decay percentages of the other three, monluster, paroxetine, and sertraline, are greater than 20%, which are the most unstable drugs. In lab-scale aerobic and anaerobic sewers, the decay percentages of metformin, glipizide, metoprolol, gemfibrozil, and atorvastatin are less than 20% within 24 h. The decay percentages of venlafaxine, citalopram, fluoxetine, salmeterol, and salbutamol within 24 h are 20%-60% and paroxetine and sertraline are close to or even exceed 80% within 6 h. Biodegradation of drugs in sewers with aerobic or anaerobic biofilms is higher than that in wastewater systems without biofilms. The results showed that when the per capita consumption of drugs is estimated by using the WBE method, the stability of drugs in wastewater and different types of sewers will significantly affect their residual concentrations.

Determination of anabasine, anatabine, and nicotine biomarkers in wastewater by enhanced direct injection LC-MS/MS and evaluation of their in-sewer stability

Wastewater-based epidemiology (WBE) has been used to estimate tobacco use in the population. However, the increased use of nicotine replacement therapies and e-cigarettes contributes to the load of nicotine metabolites in wastewater, causing over-estimation of tobacco use if nicotine metabolites were used in WBE back-estimation. This study aims to develop a rapid method for determining the tobacco-specific biomarkers, anabasine and anatabine, in wastewater and to evaluate their in-sewer stability for better estimation of tobacco use by WBE. An enhanced direct injection LC-MS/MS was developed to quantify anabasine and anatabine as well as nicotine biomarkers (nicotine, cotinine and hydroxycotinine). The method was optimal when wastewater was filtered through 0.2 μm RC syringe filters and a pre-conditioned SPE cartridge (Oasis HLB 1 cc, 30 mg) before 50 μL was injected into the LC-MS/MS system. Limits of quantification varied between 2.7 and 54.9 ng/L with recoveries from 76% to 103% for all five compounds. In sewer reactors, anabasine and anatabine were less stable than cotinine and hydroxycotinine. They were more stable in the gravity sewer reactor with <20% loss in 12 h than in the rising main sewer reactor with ~30% loss in the same period. We then applied the new method to 42 daily wastewater influent samples collected from an Australian wastewater treatment plant. The five biomarkers were detected in all samples with concentrations ranging from 9.2 to 7430 ng/L. All five compounds were positively correlated with one another. Our results suggested a high throughput analytical method for feasible application in anabasine and anatabine as biomarkers of tobacco use in routine wastewater monitoring.

The invasive butterbur contaminates stream and seepage water in groundwater wells with toxic pyrrolizidine alkaloids

Pyrrolizidine alkaloids (PAs) are persistent mutagenic and carcinogenic compounds produced by many common plant species. Health authorities recommend minimising human exposure via food and medicinal products to ensure consumer health and safety. However, there is little awareness that PAs can contaminate water resources. Therefore, no regulations exist to limit PAs in drinking water. This study measured a PA base concentration of ~ 70 ng/L in stream water adjacent to an invasive PA-producing plant Petasites hybridus (Asteraceae). After intense rain the PA concentration increased tenfold. In addition, PAs measured up to 230 ng/L in seepage water from groundwater wells. The dominant PAs in both water types corresponded to the most abundant PAs in the plants (senkirkine, senecionine, senecionine N-oxide). The study presents the first discovery of persistent plant toxins in well water and their associated risks. In addition, it for the first time reports monocrotaline and monocrotaline N-oxide in Petasites sp.

First nation-wide estimation of tobacco consumption in Spain using wastewater-based epidemiology

Wastewater-based epidemiology (WBE) has become a very useful tool to monitor a population's drug consumption or exposure to environmental and food contaminants. In this work, WBE has been applied to estimate tobacco consumption in seven Spanish regions. To this end, 24 h composite wastewater samples were taken daily for one week in 17 wastewater treatment plants, covering altogether a population of ca. 6 million inhabitants. The samples were treated by enzymatic deconjugation and the wastewater content of two human-specific nicotine metabolites (namely, cotinine and trans-3'-hydroxycotinine) was measured to estimate the daily consumption of nicotine. The population-weighted average nicotine consumption in the seven analyzed regions was 2.2 g/(day∙1000 inh.), without any daily pattern. This average estimated nicotine consumption value agreed with the value derived from official tobacco sales data. Differences in consumption among the seven studied regions were found, being Galicia, the region with the lowest rate, and the Basque Country and Catalonia those with the highest rates. However, no conclusive correlation was found between those values and the prevalence data taken from two different national surveys, nor sociodemographic and health data. This study demonstrates that this tool can complement other indicators in order to accurately assess tobacco consumption rates at regional and national levels and provides the most extensive application of the approach in the Spanish territory.

Transformation of Illicit Drugs and Pharmaceuticals in Sewer Sediments

In-sewer stability of human excreted biomarkers is a critical factor of wastewater-based epidemiology in back-estimating illicit drug and pharmaceutical use in the community. Biomarker stability has been investigated in sewers with the presence of biofilms, but the understanding in sewer sediments is still lacking. This study for the first time employed a laboratory sediment reactor to measure 18 illicit drug and pharmaceutical biomarkers under gravity sewer environments with the presence of sediments. Biomarkers exhibited various stability patterns due to transformation processes occurring in the bulk wastewater and sediments. The attenuation of a biomarker by sediments is driven by complex processes involving biodegradation, diffusion, and sorption, which is directly proportional to the ratio of sediment surface area against wastewater volume. The sediment-driven transformation coefficients of biomarkers are higher than the accordingly biofilm-mediated rates because of stronger microbial activities in sediments. Additionally, the stability of most biomarkers was insensitive to the natural pH variation in sewers, except for a few compounds (e.g., methadone, ketamine, and paracetamol) susceptible to pH changes. In general, this study delineates the stability data of various biomarkers in gravity sewers with sediments, which are novel and long-missing information for wastewater-based epidemiology and improve the reliability of back-estimation in complex sewer networks.

Assessing alcohol consumption through wastewater-based epidemiology: Spain as a case study

BACKGROUND

In this study, an alternative and complementary method to those approaches currently used to estimate alcohol consumption by the population is described. This method, known as wastewater-based epidemiology (WBE), allows back-calculating the alcohol consumption rate in a given population from the concentrations of a selected biomarker measured in wastewater.

METHODS

Composite (24-h) wastewater samples were collected at the inlet of 17 wastewater treatment plants located in 13 Spanish cities for seven consecutive days in 2018. The sampled area covered 12.8% of the Spanish population. Wastewater samples were analyzed to determine the concentration of ethyl sulfate, the biomarker used to back-calculate alcohol consumption.

RESULTS

Alcohol consumption ranged from 4.5 to 46 mL/day/inhabitant. Differences in consumption were statistically significant among the investigated cities and between weekdays and weekends. WBE-derived estimates of alcohol consumption were comparable to those reported by its corresponding region in the Spanish National Health Survey in most cases. At the national level, comparable results were obtained between the WBE-derived annual consumption rate (5.7 ± 1.2 L ethanol per capita (aged 15+)) and that reported by the National Health Survey (4.7 L ethanol per capita (aged 15+)).

CONCLUSIONS

This is the largest WBE study carried out to date in Spain to estimate alcohol consumption rates. It confirms that this approach is useful for establishing spatial and temporal patterns of alcohol consumption, which could contribute to the development of health care management plans and policies. Contrary to established methods, it allows obtaining information in a fast and relatively economical way.

Symbiosis of sulfate-reducing bacteria and methanogenic archaea in sewer systems

Sulfide and methane emissions always simultaneously exist in natural environment and constitute a major topic of societal concern. However, the metabolic environments between sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) exist a great difference, which seems to be opposite to the coexisting phenomenon. To explore this issue, the comprehensive biofilm structures, substrate consuming and metabolism pathways of SRB and MA were investigated in a case study of urban sewers. The results showed that, due to the stricter environmental requirements of MA than SRB, SRB became the preponderant microorganism which promoted the rapid generation of sulfide in the initial period of biofilm formation. According to a metagenomic analysis, the SRB appeared to be more preferential than MA in sewers, and the preponderant SRB could provide a key medium (Methyl-coenzyme M) for methane metabolism. Therefore, the diversity of MA gradually increased, and the symbiosis system formed preliminarily. In addition, via L-cysteine, methane metabolism also participated in sulfide consumption which was involved in cysteine and methionine metabolism. This phenomenon of sulfide consumption led to the forward reaction of sulfide metabolism, which could promote sulfide generation while stabilizing the pH value (H⁺ concentration) and S^2- concentrations which should have inhibited SRB and MA production. Therefore, the heavily intertwined interactions between sulfide and methane metabolism provided environmental security for SRB and MA, and completely formed the symbiosis between SRB and MA. Based on these findings, an ecological model involving synergistic mechanism between sulfide and methane generation is proposed and this model can also improve understanding on the symbiosis of SRB and MA in the natural environment.

Sale-based estimation of pharmaceutical concentrations and associated environmental risk in the Japanese wastewater system

Information on sales and emission of selected pharmaceuticals were used to predict their concentrations in Japanese wastewater influent through a >300 of pharmaceuticals data sink. A combined wastewater-based epidemiology and environmental risk analysis follow was established. By comparing predicted environmental concentrations (PECs) of pharmaceuticals in wastewater influent against measured environmental concentrations (MECs) reported in previous studies, it was found that the model gave accurate results for 17 pharmaceuticals (0.5 < PEC/MEC < 2), and acceptable results for 32 out of 40 pharmaceuticals (0.1 < PEC/MEC < 10). Although the majority of pharmaceuticals considered in the model were antibiotics and analgesics, pranlukast, a receptor antagonist, was predicted to have the highest concentration in wastewater influent. With regard to the composition of wastewater effluent, the Estimation Program Interface (EPI) suite was used to predict pharmaceutical removal through activated sludge treatment. Although the performance of the EPI suite was variable in terms of accurate prediction of the removal of different pharmaceuticals, it could be an efficient tool in practice for predicting removal under extreme scenarios. By using the EPI suite with input data on PEC in the wastewater influent, the PEC values of pharmaceuticals in wastewater effluent were predicted. The concentrations of 26 pharmaceuticals were relatively high (>1 μg/L), and the PECs of 6 pharmaceuticals were extremely high (>10 μg/L) in wastewater effluent, which could be attributed to their high usage rates by consumers and poor removal rates in wastewater treatment plants (WWTPs). Furthermore, environmental risk assessment (ERA) was carried out by calculating the ratio of predicted no effect concentration (PNEC) to PEC of different pharmaceuticals, and it was found that 9 pharmaceuticals were likely to have high toxicity, and 54 pharmaceuticals were likely to have potential toxicity. It is recommended that this is further investigated in detail. The priority screening and environmental risk assessment results on pharmaceuticals can provide reliable basis for policy-making and environmental management.

Considerations for assessing stability of wastewater-based epidemiology biomarkers using biofilm-free and sewer reactor tests

Wastewater-based epidemiology is an increasingly popular method for analysing drugs or metabolites excreted by populations. The in-sewer transformation of biomarkers is important but often receives little consideration in published studies. Many studies publish stability under biofilm-free conditions only, which do not represent actual sewer conditions. This study aims to fill a gap in the field by comparing the wastewater stability of 33 licit drug and pharmaceutical biomarkers in biofilm-free (BFF) conditions to stability in sewer biofilm reactors. All but one biomarker was stable under BFF conditions, whereas most transformed in sewer biofilm reactors. Sewer reactor results tended to overestimate the degradation in pilot and actual sewers, whereas BFF stability had no clear relationship to stability in pilot and actual sewers. Our results provide additional basis for more informed interpretation of biofilm-free and sewer reactor stability results for past and future WBE studies.

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.

New approach for the measurement of long-term alcohol consumption trends: Application of wastewater-based epidemiology in an Australian regional city

BACKGROUND

Wastewater-based epidemiology (WBE) provides complementary information to traditional self-report methods for estimating substance use within a population. WBE was applied to estimate the consumption of alcohol in an Australian rural city (population estimated 100,000) over 6 years.

METHODS

A total of 352 wastewater samples were analysed from a wastewater treatment plant located in South-East Queensland, Australia, from 2012 to 2017. The concentration of an alcohol biomarker, ethyl sulphate, was quantified by liquid chromatography tandem mass spectrometry and used to estimate per-capita consumption. The WBE results were compared with alcohol consumption estimates based on national taxation data and self-reported national survey data in Australia.

RESULTS

Average daily alcohol consumption estimated by WBE was between 19 and 30 mL/person/day for the population aged 15 years and older during the six-year period. Alcohol consumption decreased 4 % per annum on average over the study period. Our data showed higher rates of consumption on weekends and public holidays when compared to consumption between Monday and Thursday. The comparative trend of WBE data was consistent with the national alcohol survey and taxation statistics on alcoholic beverages over the same period.

CONCLUSIONS

A clear decline in alcohol consumption in the catchment was observed during the sampling period, which reflected similar changes in consumption from taxation statistics and self-report survey data. Expected variations in weekly consumption and public holidays were also identified. This study demonstrates the potential of WBE for long-term monitoring of alcohol consumption in evaluating the effectiveness of local and national alcohol policies and prevention programs.

Current status and future prospects of sewer biofilms: Their structure, influencing factors, and substance transformations

With rapid urbanization, sewer systems are extensively being constructed for the collection and transportation of sewage to minimize the severe environmental and health issues, especially relating to the spread diseases. The existence of abundant biofilms on the inner walls of sewers could lead to potential risks such as sewer explosions, poisonous gas leaks, and pipe corrosions with the transformations of various kinds of pollutants. Therefore, it is urgent to clarify their inner mechanisms to safely govern sewer systems. In this study, the characteristics of sewer biofilms including their structure, influencing factors, and substance transformations were analyzed in-depth. The results reveal that sewer biofilms (1.0 mm depth approximately) consist of large quantities of inorganic and some organic substances, while the abundant functional genus of the bacteria and archaea are summarized. Sewer biofilms influencing factors were determined to be sewer operation mode, sewage characteristics, and shear stress. Further, the transformation of organics, sulfur, and nitrogen as well as emerging micropollutants (such as, biomarkers, antibiotic resistance genes, and engineered nanoparticles) was investigated to guarantee sewer security and public health. Therefore, the current review could be considered as guidance for researchers and decision-makers.

Fate of environmental pollutants

This annual review covers the literature published in 2018 on topics related to the occurrence and fate of environmental pollutants in wastewater. Due to the vast amount of literature published on this topic, we have discussed only a portion of the quality research publications, due to the limitation of space. The abstract search was carried out using Web of Science, and the abstracts were selected based on their relevance. In a few cases, full-text articles were referred to understand new findings better. This review is divided into the following sections: antibiotic-resistant bacteria (ARBs) and antibiotic-resistant genes (ARGs), disinfection by-products (DBPs), drugs of abuse (DoAs), estrogens, heavy metals, microplastics, per- and polyfluoroalkyl compounds (PFAS), pesticides, and pharmaceuticals and personal care products (PPCPs), with the addition of two new classes of pollutants to previous years (DoAs and PFAS).

Experimental Investigation and Modeling of the Transformation of Illicit Drugs in a Pilot-Scale Sewer System

In-sewer stability of illicit drug biomarkers has been evaluated by several reactor-based studies, but less has been done in sewer pipes. Experiments conducted in sewer pipes have advantages over lab-scale reactors in providing more realistic biomarker stability due to the flow and biological dynamics. This study assessed the transportation and transformation of seven illicit drug biomarker compounds in a pilot-scale rising main and a gravity sewer pipe. Biomarkers presented diverse stability patterns in the pilot sewers, based on which a drug transformation model was calibrated. This model was subsequently validated using transformation data sets from the literature, aiming to demonstrate the predictability of the pilot-based transformation coefficients under varying sewer conditions. Furthermore, transformation coefficients for five investigated biomarkers were generated from four studies, and their prediction capabilities under the pilot-sewer conditions were jointly assessed using performance statistics. The transformation model was successful in simulating the in-sewer stability for most illicit drugs. However, further study is required to delineate the sources and pathways for those compounds with potential formations to be simulated in the transformation model. Overall, the transformation model calibrated using the pilot-sewer data is a credible tool for the application of wastewater-based epidemiology.

Can water quality indicators and biomarkers be used to estimate real-time population?

The precise population estimation, short-term or real-time, is crucial to social and civil management, such as public resource distribution, education budgets, health care, and public safety. In this paper, we reviewed the methods for estimation of real-time population. For real-time population estimation, especially for a certain wastewater treatment plant catchment, many water quality indicators and biomarkers were selected as potential markers and their stability, consumption coefficient, and uncertainty were assessed. The conventional water quality indicators, such as wastewater discharge volume, chemical oxygen demand, biochemical oxygen demand, ammonia nitrogen, and total phosphorus, were used to calculate the serving population within a WWTP catchment. These parameters are all affected by the behavior, living habits and health conditions of people in different regions. Among them, wastewater discharge volume and ammonia might be more suitable for population estimation than the other parameters which may be influenced by additional industrial discharge. Moreover, acesulfame could be used to estimate the general population, while caffeine, tobacco, and carbamazepine could be applied as biomarkers for a specific population. Furthermore, the per capita loading differ should be considered and measured independently. To reduce the uncertainty of population, comprehensive model with multi-parameters should be developed and applicability should be checked.

Trends in nicotine consumption between 2010 and 2017 in an Australian city using the wastewater-based epidemiology approach

Monitoring smoking prevalence is key to assessing responses to tobacco control measures, and evaluating associated health and economic costs. Estimates of tobacco consumed in Australia are based on various data sources - tax excise clearances, sales, and self-report surveys. There are limitations with each of these data sources which makes triangulation of cigarette use estimates by multiple methods important. Wastewater-based epidemiology, the systematic sampling and analysis of wastewater, is now a routine method to measure and monitor human exposure to a range of chemicals. This study provides a high frequency long-term temporal assessment of exposure to nicotine, the main addictive component of tobacco, using this approach. 291 archived wastewater samples collected from a regional city catchment from 2010 to 2017 were analysed for human-specific nicotine metabolites (cotinine and trans-3'-hydroxycotinine), to estimate per capita nicotine use. Temporal trends in nicotine use determined by wastewater-based epidemiology were compared with national sales and survey data. Wastewater analysis showed a 25% reduction in the mean number of cigarette equivalents consumed from 2010 to 2017, representing a 3% annual decline. These findings are in good agreement with estimates based on surveys and sales data, indicating annual declines of 5% and 4%, respectively. Findings of this study demonstrate WBE to be a relatively cost-effective and objective approach to reporting long-term data on nicotine consumption. When combined with alternative data sources, and valuable sociodemographic information of surveys, wastewater-based epidemiology helps to refine our estimates and understanding of the total impacts of smoking.

Assessment of drugs of abuse in a wastewater treatment plant with parallel secondary wastewater treatment train

In this study, 24-hour composite wastewater samples were collected from a wastewater treatment plant of New Zealand with parallel secondary treatment units. The aim was to investigate the occurrence, removal, and consumption of 13 drugs of abuse (DOAs) including illicit drugs, alcohol, nicotine, and their metabolites. The filtered samples were analysed through direct injection on LC-MS/MS. Ethyl sulfate, one of the major metabolites of alcohol, was detected at the highest concentration (mean = 8300 ng/L) in wastewater influent. The mean concentrations of methamphetamine and hydroxycotinine in the influent were found to be 935 ng/L and 5000 ng/L, respectively. Amphetamine (383 ng/L) and cocaine (286 ng/L) were detected at the highest concentrations in the effluent. The removal efficiency of the treatment plant varied for DOAs: >99% for morphine, ethyl sulfate, and hydroxycotinine and <50% for methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP). Primary treatment did not show any significant removal of DOAs while the removal efficiencies of total monitored DOAs by Membrane Bioreactor (MBR) and Bardenpho processes were found to be similar (~95% removal). The population was estimated using hydrochemical parameters and human urine biomarkers and showed good agreement with wastewater treatment plant's estimates. Weekday-weekend variation in the consumption of alcohol and methamphetamine was found to be significant, with a higher estimated consumption during the weekends. Monitored DOAs in influent were present at highest concentrations during summer (23 μg/L), at low concentrations during winter (17 μg/L), and at lowest concentrations during heavy rainfall event (11 μg/L), possibly due to dilution. The population normalised mass loads of DOAs were found to correlate with their metabolites, and morphine was found to correlate with nicotine metabolites.

Systematic evaluation of biomarker stability in pilot scale sewer pipes

Transformation of biomarkers (or their stability) during sewer transport is an important issue for wastewater-based epidemiology (WBE). Most studies so far have been conducted in the laboratory, which usually employed unrealistic conditions. In the present study, we utilized a pilot sewer system including a gravity pipe and a rising main pipe to investigate the fate of 24 pharmaceutical biomarkers. A programmable logic controller was used to control and monitor the system including sewer operational conditions and wastewater properties. Sequential samples were collected that can represent hydraulic retention time (HRT) of up to 8 h in a rising main and 4 h in a gravity sewer. Wastewater parameters and biomarker concentrations were analysed to evaluate the stability and transformation kinetics. The wastewater parameters of the pilot system were close to the conditions of real sewers. The findings of biomarker transformation were also close to real sewer data with seventeen biomarkers reported as stable while buprenorphine, caffeine, ethyl-sulfate, methadone, paracetamol, paraxanthine and salicylic acid degraded to variable extents. Both zero-order and first-order kinetics were used to model the degradation of unstable biomarkers and interestingly the goodness of fit R² for the zero-order model was higher than the first-order model for all unstable biomarkers in the rising main. The pilot sewer system simulates more realistic conditions than benchtop laboratory setups and may provide a more accurate approach for assessing the in-sewer transformation kinetics and stability of biomarkers.