National wastewater reconnaissance of artificial sweetener consumption and emission in Australia

Reporting population size in wastewater-based epidemiology: A scoping review

Knowledge of the number of people present in a catchment is fundamental for the assessment of spatio-temporal trends in wastewater-based epidemiology (WBE). Accurately estimating the number of people connected to wastewater catchments is challenging however, because populations are dynamic. Methods used to estimate population size can significantly influence the calculation and interpretation of population-normalised wastewater data (PNWD). This paper systematically reviews the reporting of population data in 339 WBE studies. Studies were evaluated based on their reporting of population size, the source of population data, the population calculation methods, and the uncertainties in population estimates. Most papers reported population size (96 %) and the source of population data (60 %). Fewer studies reported the uncertainties in their population data (50 %) and the methods used to calculate these estimates (28 %). This is relevant because different methods have unique strengths and limitations which can affect the accuracy of PNWD. Only 64 studies (19 %) reported all four components of population data. The reporting of population data has remained consistent in the past decade. Based on the findings, we recommend generalised reporting criteria for population data in WBE. As WBE is further mainstreamed and applied, the clear and comprehensive reporting of population data will only become increasingly important.

Evaluation of aspartame effects at environmental concentration on early development of zebrafish: Morphology and transcriptome1

The use of aspartame as an artificial sweetener is prevalent in a wide range of everyday food products, potentially leading to health complications such as obesity, diabetes mellitus, autism spectrum disorders, and neurodegeneration. Aspartame has also been detected in natural water bodies at a concentration of 0.49 μg/L, yet research on its ecotoxicological effects on aquatic life remains scarce. This study aimed to investigate the potential negative effects of environmentally relevant concentrations of aspartame on the development of various tissues and organs in zebrafish embryos. We used a zebrafish model to treat embryos with aspartame at environmental concentration and those higher than in the environment-up to 1000 times. We observed that after exposure to aspartame body length increased, pigmentation was delayed, and neutrophil production inhibited in zebrafish. Furthermore, transcriptome analysis revealed that early exposure of zebrafish embryos to aspartame affected the transcriptomics of various systems, primarily by downregulating genes related to immune cell production, eye and optic nerve development, nervous system development, and growth hormone-related transcription. Most of the genes associated with ferroptosis were upregulated. This study provides new insights into the ecotoxicological effects of aspartame on aquatic environments.

Are we using more sugar substitutes? Wastewater analysis reveals differences and rising trends in artificial sweetener usage in Swedish urban catchments

The market for artificial sweeteners as substitutes for conventional sugar (sucrose) is growing, despite potential health risks associated with their intake. Estimating population usage of artificial sweeteners is therefore crucial, and wastewater analysis can serve as a complement to existing methods. This study evaluated spatial and temporal usage of artificial sweeteners in five Swedish communities based on wastewater analysis. We further compared their levels measured in wastewater with the restrictions during the COVID-19 pandemic in Sweden and assessed health risks to the Swedish population. Influent wastewater samples (n = 194) collected in March 2019-February 2022 from communities in central and southern Sweden were analyzed for acesulfame, saccharin, and sucralose using liquid-chromatography coupled with tandem mass spectrometry. Spatial differences in loads for individual artificial sweetener were observed, with sucralose being higher in Kalmar (southern Sweden), and acesulfame and saccharin in Enköping and Östhammar (central Sweden). Based on sucrose equivalent doses, all communities showed a consistent prevalence pattern of sucralose > acesulfame > saccharin. Four communities with relatively short monitoring periods showed no apparent temporal changes in usage, but the four-year monitoring in Uppsala revealed a significant (p < 0.05) annual increase of ∼19 % for sucralose, ∼9 % for acesulfame and ∼8 % for saccharin. This trend showed no instant or delayed effects from COVID-19 restrictions, reflecting positively on the studied population which retained similar exposure to the artificial sweeteners despite potential pandemic stresses. Among the three artificial sweeteners, only acesulfame's levels were at the lower end of the health-related threshold for consumption of artificially sweetened beverages; yet, all were far below the acceptable daily intake, indicating no appreciable health risks. Our study provided valuable, pilot insights into the spatio-temporal usage of artificial sweeteners in Sweden and their associated health risks. This shows the usefulness of wastewater analysis for public health authorities wishing to assess future relevant interventions.

Acesulfame and other artificial sweeteners in a wastewater treatment plant in Alberta, Canada: Occurrence, degradation, and emission

Acesulfame (ACE), sucralose (SUC), cyclamate (CYC), and saccharin (SAC) are widely used artificial sweeteners that undergo negligible metabolism in the human body, and thus ubiquitously exist in wastewater treatment plants (WWTPs). Due to their persistence in WWTPs, ACE and SUC are found in natural waters globally. Wastewater samples were collected from the primary influent, primary effluent, secondary effluent, and final effluent of a WWTP in Alberta, Canada between August 2022 and February 2023, and the artificial sweeteners concentrations were measured by LC-MS/MS. Using wastewater-based epidemiology, the daily per capita consumption of ACE in the studied wastewater treatment plant catchment was estimated to be the highest in the world. Similar to other studies, the removal efficiency in WWTP was high for SAC and CYC, but low or even negative for SUC. However, ACE removal remained surprisingly high (>96%), even in the cold Canadian winter months. This result may indicate a further adaptation of microorganisms capable of biodegrading ACE in WWTP. The estimated per capita discharge into the environment of ACE, CYC, and SAC is low in Alberta due to the prevalent utilization of secondary treatment throughout the province, but is 17.4-18.8 times higher in Canada, since only 70.3% of total discharged wastewater in Canada undergoes secondary treatment.

Wastewater contaminants in a fractured bedrock aquifer and their potential use as enteric virus indicators

Domestic wastewater is a source of persistent organic pollutants and pathogens to the aquatic environment, including groundwater aquifers. Wastewater contaminants include a variety of personal care products, pharmaceuticals, endocrine disrupters, bacteria, and viruses. Groundwater from 22 wells completed in a semi-confined to confined, fractured Silurian dolostone aquifer in southern Wellington County, Ontario, Canada, was analyzed for 14 organic wastewater contaminants (4 artificial sweeteners, 10 pharmaceuticals) as well as E. coli, total coliforms, and 6 human enteric viruses. Enteric viruses were detected in 8.6% of 116 samples, and at least one organic wastewater contaminant was detected in 82% of the wells (in order of decreasing detection frequency: acesulfame, ibuprofen, sulfamethoxazole, triclosan, carbamazepine, and saccharin). Virus indicator metrics [positive and negative predictive values (PPV, NPV), sensitivity, specificity] were calculated at the sample and well level for the organic wastewater compounds, E. coli, and total coliforms. Fecal bacteria were not good predictors of virus presence (PPV = 0%-8%). Of the potential chemical indicators, triclosan performed the best at the sample level (PPV = 50%, NPV = 100%), and ibuprofen performed the best at the well level (PPV = 60%, NPV = 67%); however, no samples had triclosan or ibuprofen concentrations above their practical quantification limits. Therefore, none of the compounds performed sufficiently well to be considered reliable for assessing the potential threat of enteric viruses in wastewater-impacted groundwater in this bedrock aquifer. Future studies need to evaluate the indicator potential of persistent organic wastewater contaminants in different types of aquifers, especially in fractured rock where heterogeneity is strong.IMPORTANCEAssessing the potential risk that human enteric viruses pose in groundwater aquifers used for potable water supply is complicated by several factors, including: (i) labor-intensive methods for the isolation and quantification of viruses in groundwater, (ii) the temporal variability of these viruses in domestic wastewater, and (iii) their potentially rapid transport in the subsurface, especially in fractured rock aquifers. Therefore, aquifer risk assessment would benefit from the identification of suitable proxy indicators of enteric viruses that are easier to analyze and less variable in wastewater sources. Traditional fecal indicators (e.g., E. coli and coliforms) are generally poor indicators of enteric viruses in groundwater. While many studies have examined the use of pharmaceutical and personal care products as tracers of domestic wastewater and fecal pollution in the environment, there is a paucity of data on the potential use of these chemical tracers as enteric virus indicators, especially in groundwater.

Taste traces: Capsaicin and sweeteners as anthropogenic markers in municipal wastewater

Dietary-derived substances possess significant potential as anthropogenic markers owing to the large consumption and different intake habit. To investigate and evaluate such markers, wastewater samples from 35 wastewater treatment plants across 29 Chinese cities were collected to analyze artificial sweeteners (acesulfame and cyclamate) and natural spicy compounds (capsaicin and dihydrocapsaicin). Acesulfame (mean: 14.6 μg/L), cyclamate (mean: 24.3 μg/L), and capsaicin (mean: 101 ng/L) can be further investigated as anthropogenic markers due to their high detection frequency at high concentrations. Spatial use patterns revealed that acesulfame (5.31 g/d/1000 inhabitants (inh)) and cyclamate (8.16 g/d/1000 inh) use in northern China notably surpassed that in southern China (1.79 g/d/1000 inh and 3.23 g/d/1000 inh, p < 0.05). Conversely, chili pepper use was significantly higher (p < 0.05) in southern China (6702 g/d/1000 inh) than in northern China (2751 g/d/1000 inh), signifying a preference for sweetness in the northern regions and a predilection for spiciness in the southern regions. The total annual use of acesulfame (1842 t), cyclamate (3110 t), and chili (18.4 million tonnes) in China was estimated by this study, which was close to the national statistical production. In addition, sweetener use was negatively associated with the elderly population ratio, suggesting that the elderly population might not consume sweet foods. This study reveals the dietary sources of anthropogenic markers, highlighting the need for further research on the environmental implications of such markers.

A One-Health environmental risk assessment of contaminants of emerging concern in London's waterways throughout the SARS-CoV-2 pandemic

The SARS-CoV-2 pandemic had huge impacts on global urban populations, activity and health, yet little is known about attendant consequences for urban river ecosystems. We detected significant changes in occurrence and risks from contaminants of emerging concern (CECs) in waterways across Greater London (UK) during the pandemic. We were able to rapidly identify and monitor large numbers of CECs in n = 390 samples across 2019-2021 using novel direct-injection liquid chromatography-mass spectrometry methods for scalable targeted analysis, suspect screening and prioritisation of CEC risks. A total of 10,029 measured environmental concentrations (MECs) were obtained for 66 unique CECs. Pharmaceutical MECs decreased during lockdown in 2020 in the R. Thames (p ≤ 0.001), but then increased significantly in 2021 (p ≤ 0.01). For the tributary rivers, the R. Lee, Beverley Brook, R. Wandle and R. Hogsmill were the most impacted, primarily via wastewater treatment plant effluent and combined sewer overflows. In the R. Hogsmill in particular, pharmaceutical MEC trends were generally correlated with NHS prescription statistics, likely reflecting limited wastewater dilution. Suspect screening of ∼ 1,200 compounds tentatively identified 25 additional CECs at the five most impacted sites, including metabolites such as O-desmethylvenlafaxine, an EU Watch List compound. Lastly, risk quotients (RQs) ≥ 0.1 were calculated for 21 compounds across the whole Greater London freshwater catchment, of which seven were of medium risk (RQ ≥ 1.0) and three were in the high-risk category (RQ ≥ 10), including imidacloprid (RQ = 19.6), azithromycin (15.7) and diclofenac (10.5). This is the largest spatiotemporal dataset of its kind for any major capital city globally and the first for Greater London, representing ∼ 16 % of the population of England, and delivering a foundational One-Health case study in the third largest city in Europe across a global pandemic.

Levels, consumption, and variations of eight artificial sweeteners in the wastewater treatment plants of Dalian city, China

Artificial sweeteners (ASs) are emerging contaminants in the environment, primarily derived from wastewater treatment plant (WWTP) effluents. In this study, the influents and effluents of three WWTPs in the Dalian urban area, China, were analyzed for the distribution of 8 typical ASs to investigate their seasonal fluctuations in the WWTPs. The results showed that acesulfame (ACE), sucralose (SUC), cyclamate (CYC), and saccharin (SAC) were both detected in the influent and effluent water samples of WWTPs, with concentrations ranging from not detected (ND) to 14.02 μg·L-1. In addition, SUC was the most abundant ASs type, accounting for 40 %-49 % and 78 %-96 % of the total ASs in the influent and effluent water, respectively. The WWTPs revealed high removal efficiencies of CYC, SAC, and ACE, while the SUC removal efficiency was poor (26 % ± 36 %). The ACE and SUC concentrations were higher in spring and summer, and all ASs showed lower levels in winter, which may be caused by the high consumption of ice-cream in warmer months. The per capita ASs loads in the WWTPs were determined in this study based on the wastewater analysis results. The calculated per capita daily mas loads for individual ASs ranged from 0.45 g·d-1·1000p-1 (ACE) to 2.04 g·d-1·1000p-1 (SUC). In addition, the relationship between per capita ASs consumption and socioeconomic status showed no significant correlation.

High resolution mass spectrometry (HRMS) determination of drugs in wastewater and wastewater based epidemiology in Cadiz Bay (Spain)

Multi-residue methods for the determination of the myriad of compounds of emerging concern (CECs) entering in the environment are key elements for further assessment on their distribution and fate. Here, we have developed an analytical protocol for the simultaneous analysis of 195 prescription, over-the-counter, and illicit drugs by using a combination of solid phase extraction (SPE) and determination by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). The method was applied to the analysis of influent sewage samples from 3 wastewater treatment plants (WWTPs) from Cadiz Bay (SW Spain), enabling the quantification of more than 100 pharmaceuticals, 19 of them at average concentrations higher than 1 μg L^-1, including caffeine (92 μg L^-1), paracetamol (72 μg L^-1), and ibuprofen (56 μg L^-1), as well as several illicit drugs (e.g., cocaine). Wastewater based epidemiology (WBE) was applied for 27 of the detected compounds to establish their consumption in the sampling area, which has been never attempted before. Caffeine, naproxen, and salicylic acid stood out because of their high consumption (638, 51, and 20 g d^-1·1000pop^-1, respectively). Regarding illicit drugs, cocaine showed the highest frequency of detection and we estimated an average consumption of 3683 mg d^-1·1000pop^-1 in Cadiz Bay. The combination of new HRMS methods, capable of discriminating thousands of chemicals, and WBE will allow for a more comprehensive characterization of chemical substances and their consumption in urban environments in the near future.

Acesulfame allows the tracing of multiple sources of wastewater and riverbank filtration

Aquifers providing drinking water are increasingly threatened by emerging contaminants due to wastewater inputs from multiple sources. These inputs have to be identified, differentiated, and characterized to allow an accurate risk assessment and thus ensure the safety of drinking water through appropriate management. We hypothesize, that in climates with seasonal temperature variations, the sweetener acesulfame potassium (ACE) provides new pathways to study wastewater inputs to aquifers. Specifically, this study investigates the temperature-driven seasonal oscillation of ACE to assess multiple sources of wastewater inputs at a riverbank filtration site. ACE concentrations in the river water varied from 0.2 to 1 μg L^-1 in the cold season (T < 10 °C) to 0-0.1 μg L^-1 in the warm season (T > 10 °C), due to temperature-dependent biodegradation during wastewater treatment. This oscillating signal could be traced throughout the aquifer over distances up to 3250 m from two different infiltration sources. A transient numerical model of groundwater flow and ACE transport was calibrated over hydraulic heads and ACE concentrations, allowing the accurate calculation of mixing ratios, travel times, and flow-path directions for each of the two infiltration sources. The calculated travel time from the distant infiltration source was of 67 days, while that from the near source was of 20 days. The difference in travel times leads to different potential degradation of contaminants flowing into the aquifer from the river, thus demonstrating the importance of individually assessing the locations of riverbank infiltration. The calibrated ACE transport model allowed calculating transient mixing ratios, which confirmed the impact of river stage and groundwater levels on the mixing ratio of the original groundwater and the bank filtrate. Therefore, continuous monitoring of ACE concentrations can help to optimize the management of the water works with the aim to avoid collection of water with very short travel times, which has important regulative aspects. Our findings demonstrate the suitability of ACE as a transient tracer for identifying multiple sources of wastewater, including riverbank filtration sites affected by wastewater treatment plant effluents. ACE seasonal oscillation tracking thus provides a new tool to be used in climates with pronounced seasonal temperature variations to assess the origins of contamination in aquifers, with time and cost advantages over multi-tracer approaches.

Use of artificial sweeteners and caffeine in a population of Hanoi: An assessment by wastewater-based epidemiology

Monitoring the consumption of artificial sweeteners in the population is essential to help public health authorities understand the level of sugar consumption. There is a gap in knowledge of patterns and levels of artificial sweetener consumption in Vietnam. Using wastewater-based epidemiology (WBE), this study aims to evaluate the use of artificial sweeteners in an urban population in Hanoi, Vietnam. A total of 184 wastewater samples were collected at two sampling sites in an urban canal, receiving sewage from over 400,000 people in three different periods between 2018 and 2020. The population normalized per capita consumption of the five detected artificial sweeteners varied from 0.87 mg d^-1 p^-1 (sucralose) to 5.2 mg d^-1 p^-1 (aspartame). The daily consumption of artificial sweeteners was found to be stable throughout the week, however the consumption of artificial sweeteners was influenced by season with higher consumption in summer. Significant correlations (p < 0.01) were found among levels of artificial sweeteners and caffeine in urban canal samples, suggesting these chemicals had common sources. Population-weighted consumption load of artificial sweeteners and caffeine was compared in Vietnam, China and Australia, and the per capita consumption load mainly depended on the habitual of tea/coffee drinking in different countries. This was the first study that provided information on the artificial sweetener consumption by wastewater analysis in Vietnam. However, several sources of uncertainty (sample collection, population estimation, other sources of artificial sweeteners in wastewater, etc.) were acknowledged in this study. Further investigations on the spatial-temporal variation of artificial sweetener consumption with more intensive sampling scheme in Vietnam are recommended.

Seasonal biodegradation of the artificial sweetener acesulfame enhances its use as a transient wastewater tracer

The persistence of the artificial sweetener acesulfame potassium (ACE) during wastewater treatment and subsequently in the aquatic environment has made it a widely used tracer of wastewater inputs to both surface water and groundwater. However, the recently observed biodegradation of ACE during wastewater treatment has questioned the validity of this application. In this study, we assessed the use of ACE not only as a marker of wastewater, but also as a transient wastewater tracer that allows both the calculation of mixing ratios and travel times through the aquifer as well as the calibration of transient groundwater flow and mass transport models. Our analysis was based on data obtained in a nearly 8-year river water and groundwater sampling campaign along a confirmed wastewater-receiving riverbank filtration site located close to a drinking water supply system. We provide evidence that temperature controls ACE concentration and thus its seasonal oscillation. River water data showed that ACE loads decreased from 1.5-4 mg·s^-1 in the cold season (December to June; T<10 °C) to 0-0.5 mg·s^-1 in the warm season (July to November; T>10 °C). This seasonal variability of >600% was detectable in the aquifer and preserved >3 km, with ACE concentrations oscillating between <LOQ in the warm season up to 1 μg·L^-1 in the cold season. The large seasonal variation in ACE concentrations during wastewater treatment, compared to the other sweeteners (sucralose, cyclamate, and saccharin) and chloride enables its use as a transient tracer of wastewater inflows and riverbank filtration. In addition, the arrival time of the ACE concentration peak can be used to estimate groundwater flow velocity and mixing ratios, thereby demonstrating its potential in the calibration of groundwater numerical models.

Occurrence and removal of four artificial sweeteners in wastewater treatment plants of China

Artificial sweeteners discharged into aquatic environments have raised concern because of their ubiquitous occurrence and potential biological effect. And some of them, such as sucralose (SUC) and acesulfame (ACE), have been identified as emerging contaminants. Wastewater treatment plants (WWTPs) are considered as important sources and sinks of artificial sweeteners discharged into the environment. In this study, the occurrence and removal of four representative artificial sweeteners in 12 WWTPs located in different provinces of China were investigated. The results showed that artificial sweeteners were detected widely in the investigated WWTPs. The median concentrations of the four target artificial sweeteners were detected in influents at levels of 0.03-3.85 μg L^-1 and decreased in the order of SUC > ACE > aspartame (APM) > neotame (NTM). Additionally, the per capita mass loads of total artificial sweeteners in the WWTPs could be affected by the location of the WWTPs and were higher in southern cities than in northern cities. It was also found that there was a distinct linear correlation between the per capita mass load of ACE in influents and population density. During the treatment of WWTPs, the overall removal efficiency of artificial sweeteners ranged from -116% to 99.1%. Among the target artificial sweeteners, SUC and ACE might have potential risk to aquatic environments based on the calculation of the risk quotient. Thus, advanced treatment processes were carried to further remove SUC and ACE to reduce their long-term cumulative effect. Overall, UV/H₂O₂ and UV/PDS showed a better effect than granular activated carbon (GAC) adsorption in the removal of artificial sweeteners. The reaction constants of ACE by UV/H₂O₂ and UV/PDS were higher than those of SUC, which is related to molar extinction coefficients. Meanwhile, the adsorption ability of GAC adsorption for SUC was better than that of ACE, which is in correlation with the octanol-water partition coefficient. By comparison of removal efficiency, UV/PDS was considered as the most suitable advanced treatment process to remove ACE and SUC.

Seasonal occurrence, removal and mass loads of artificial sweeteners in the largest water reclamation plant in China

Artificial sweeteners (ASs) are of growing concern as an emerging contaminant. In the study, the seasonal occurrence, removal and mass load of six ASs in sewage, suspended particulate matter (SPM) and sludge were investigated throughout the treatment process of the largest water reclamation plant in China. The highest ASs concentrations in the influent (13.0 μg/L), effluent (2.22 μg/L), SPM (4.48 μg/g) and sludge (0.15 μg/g) were observed in the dry season, which were 1.24- to 5.0-fold higher than in the normal season and 1.06- to 37.5-fold higher than the flood season. Following treatment, ASs concentrations decreased by 24.3 %, 51.7 % and 5.1 % (on average) in primary, secondary and reclaimed processes, respectively. Among the investigated ASs, acesulfame (93.1 %) and cyclamate (98.4 %) were removed most efficiently, with removal occurring mainly in secondary processes, while sucralose exhibited the lowest removal efficiency (38.7 %). Seasonal characteristics affect the consumption of ASs, which subsequently changes the input and discharge ASs loads of STPs. The maximum mass load of ASs occurred in the dry season, ranging from 0.002 (neotame) to 1.33 mg/d/person (cyclamate), while the maximum emission load occurred in the flood season, ranging from 0.003 (neotame) to 0.83 mg/d/person (sucralose). The mass and emission load of ASs in Beijing is significantly lower than in European or the United States, due to Beijing having low per capita consumption of ASs (5.50 mg/d/person). The highest ASs risk in the receiving water occurred in the flood season due to the input of other pollution sources by rainfall runoff. Meanwhile, attention should be paid to the risk of receiving water close to the STP outlet in the dry seasons for the highest ASs concentration in the STP effluent in the season. The present study provides important guidance on controlling the input and reducing the emission of ASs in different seasons.

Deciphering natural and anthropogenic nitrate and recharge sources in arid region groundwater

Recently, the subsoils of ephemeral stream (arroyos) floodplains in the northern Chihuahuan Desert were discovered to contain large naturally occurring NO₃^- reservoirs (floodplain: ~38,000 kg NO₃-N/ha; background: ~60 kg NO₃-N/ha). These reservoirs may be mobilized through land use change or natural stream channel migration which makes differentiating between anthropogenic and natural groundwater NO₃^- sources challenging. In this study, the fate and sources of NO₃^- were investigated in an area with multiple NO₃^- sources such as accidental sewer line releases and sewage lagoons as well as natural reservoirs of subsoil NO₃^-. To differentiate sources, this study used a large suite of geochemical tools including δ¹⁵N[NO₃], δ¹⁸O[NO₃], δ¹⁵N[N₂], δ¹³C[DIC], ¹⁴C, tritium (³H), dissolved gas concentrations, major ion chemistry, and contaminants of emerging concern (CEC) including artificial sweeteners. NO₃^- at sites with the highest concentrations (25 to 229 mg/L NO₃-N) were determined to be largely sourced from naturally occurring subsoil NO₃^- based on δ¹⁵N[NO₃] (<8 ‰) and mass ratios of Cl^-/Br^- (〈100) and NO₃^-/Cl^- (>1.5). Anthropogenic NO₃^- was deciphered using mass ratios of Cl^-/Br^- (>120) and NO₃^-/Cl^- (<1), δ¹⁵N[NO₃] (>8 ‰), and CEC detections. Nitrogen isotope analyses indicated that denitrification is fairly limited in the field area. CEC were detected at 67 % of sites including ³H dead sites (<1 pCi/L) with low percent modern carbon-14 (PMC; <30 %). Local supply wells are ³H dead with low PMC; as ³H does not re-equilibrate and ¹⁴C is very slow to re-equilibrate during recirculation through infrastructure, sites with low PMC, ³H < 1 pCi/L, and CEC detections were interpreted as locations with substantial anthropogenic groundwater recharge. Neotame was used to identify locations of very recent (<15 years before present) or ongoing wastewater influxes to the aquifer. This work shows the important influence of naturally occurring subsoil NO₃^- reservoirs on groundwater in arid regions and the major contribution of artificial recharge.

RNA in Municipal Wastewater Reveals Magnitudes of COVID-19 Outbreaks across Four Waves Driven by SARS-CoV-2 Variants of Concern

There are no standardized protocols for quantifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater to date, especially for population normalization. Here, a pipeline was developed, applied, and assessed to quantify SARS-CoV-2 and key variants of concern (VOCs) RNA in wastewater at Saskatoon, Canada. Normalization approaches using recovery ratio and extraction efficiency, wastewater parameters, or population indicators were assessed by comparing to daily numbers of new cases. Viral load was positively correlated with daily new cases reported in the sewershed. Wastewater surveillance (WS) had a lead time of approximately 7 days, which indicated surges in the number of new cases. WS revealed the variant α and δ driving the third and fourth wave, respectively. The adjustment with the recovery ratio and extraction efficiency improved the correlation between viral load and daily new cases. Normalization of viral concentration to concentrations of the artificial sweetener acesulfame K improved the trend of viral load during the Christmas and New Year holidays when populations were dynamic and variable. Acesulfame K performed better than pepper mild mottle virus, creatinine, and ammonia for population normalization. Hence, quality controls to characterize recovery ratios and extraction efficiencies and population normalization with acesulfame are promising for precise WS programs supporting decision-making in public health.

Young population consume twice as much artificial sweetener than the general population - A wastewater-based assessment in China

Understanding artificial sweetener consumption patterns and levels in different demographics is important for formulating public health policies on controlling sugar consumption. There is a considerable knowledge gap with respect to the pattern of artificial sweetener consumption in China. To narrow this gap, wastewater analysis was used to assess the temporal patterns of consumption of seven artificial sweeteners in an urban population and a university town in a megacity in South China over a one-year period. Daily influent wastewater samples were collected from an urban catchment and weekly samples collected from a university sub-catchment. Population normalized per capita consumption of the four detected artificial sweeteners (cyclamate, acesulfame, sucralose and saccharin) in the university catchment (1.0-5.9 mg d^-1 p^-1) was much higher than those in urban catchment (0.5-1.3 mg d^-1 p^-1), indicating younger population consume more artificial sweeteners than the general population. The daily consumption of artificial sweeteners was found to be stable throughout the week in the urban catchment. Time-series analysis showed that an average increase in temperature of 1 °C was associated with an increase consumption of 33 μg d^-1 p^-1 for acesulfame, 15 μg d^-1 p^-1 for sucralose and 14 μg d^-1 p^-1 for saccharin. This was the first study that objectively quantified the greater consumption of artificial sweeteners (proxy for consumption of artificially sweetened food and beverages) in a younger age group when compared to the general population, which could potentially pose a risk of health related diseases.

A nationwide wastewater-based assessment of metformin consumption across Australia

Metformin is the most widely used drug to treat type 2 diabetes. Monitoring spatial patterns of metformin use could provide new insights into treatment of type 2 diabetes and the distribution among populations. This study applied a wastewater-based epidemiological (WBE) approach to estimate metformin use in different populations across Australia and compared these estimates with traditional approaches of surveys and prescription data. Twenty-four-hour influent samples were collected from 75 wastewater treatment plants (WWTPs) across Australia in 2016 and analysed for metformin. Metformin was detected in all samples ranging in concentration from 8.2 to 191 µg/L (median 58 µg/L). Concentrations were converted to population-weighted average consumption at the national level, resulting in an average consumption of 28.6 g/day/1000 people across Australia, which was within 7% of estimates from national prescription statistics. In addition, results for five out of seven states had an estimated prevalence of type 2 diabetes within 20% compared to the traditional epidemiology surveys. Spatial patterns were also observed between urban and rural settings, with higher consumption rates of metformin found in Major Cities (22.5 ± 10.9 g/d/1000 people) and Inner Regional cities (25.4 ± 13.4 g/d/1000 people) than in Outer Regional (17.0 ± 8.1 g/d/1000 people) and Remote areas (15.1 ± 7.4 g/d/1000 people). Consumption estimates were also correlated against socioeconomic factors of the specific catchment areas. Greater metformin use was correlated with populations of lower education and income levels, while positive correlations were found between metformin consumption and consumption of allopurinol, caffeine and venlafaxine. Our study provides more evidence on the distribution of metformin use across Australia, which can be used to develop public health strategies to reduce the overall burden of type 2 diabetes in specific regions.

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

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

Emission and Mass Load of Artificial Sweeteners from a Pig Farm to Its Surrounding Environment: Contribution of Airborne Pathway and Biomonitoring Potential

An investigation was conducted by determining artificial sweeteners (ASs) in 80 samples from various environmental matrices, including dry deposition, rainfall, soil, leaf, and bark samples around a pig farm in Tianjin, China. Saccharin, cyclamate, and acesulfame were predominant in dry deposition and rainfall samples. Spatially, the distribution of ASs showed a consistent trend of farm center > downwind sites > upwind sites > reference site. The annual total mass loads of saccharin (70%), cyclamate (25%), and acesulfame (5%) via dry deposition and precipitation within a 5 km radius of the pig farm were estimated at 3.9 and 6.2 kg in the average-case and worst-case scenarios, respectively, accounting for 12-18% of the overall emission, indicating that pig farms are a significant source of ASs to the atmosphere and to the vicinal environment via dry and wet deposition. The distribution trends of ASs in tree bark and leaves were similar and tree bark performed better in passively biomonitoring the AS contamination. Overall, pig farms were predicted to release 65-114, 22-38, 2.0-3.5, and 0.6-1.1 tons by feed application in China, Europe, Latin America, and North America, respectively, to the vicinal environment via dry deposition and precipitation.

Trends in artificial sweetener consumption: A 7-year wastewater-based epidemiology study in Queensland, Australia

A 7-year temporal trend study of artificial sweetener consumption was performed by determining per capital mass loads in 293 influent wastewater samples collected from a wastewater treatment plant in Australia between 2012 and 2018. Population-weighted per capita mass loads of the four detected artificial sweeteners ranged from 2.4 ± 0.8 mg d^-1 p^-1 for saccharin to 7.8 ± 2.0 mg d^-1 p^-1 for acesulfame over the study period. Negligible intra-week fluctuations were observed, however the consumption of acesulfame was seen to be significantly influenced by season with the highest consumption in summer. The consumption of sucralose and saccharin significantly increased with an annual increase rate of 10% and 6.0%. Cyclamate consumption declined over the same period with average annual decrease rate of 11%, which agrees with data from market surveys. Sucrose equivalence of total artificial sweeteners consumption showed an increase between 2012 and 2016, then decreased in 2018. This is the first long-term trend study of artificial sweetener consumption by wastewater analysis and highlights the feasibility to quantitatively measure artificial sweeter consumption over time.