Removal of residues of psychoactive substances during wastewater treatment, their occurrence in receiving river waters and environmental risk assessment

An OPRM1-SNAP-tag/CMC method to directly identify drug components in sewage

The scourge of drug addiction and abuse poses a significant challenge to society. Opioid drugs acting on μ-opioid receptor (OPRM1) make it one of the pivotal targets for drug addiction. In the past decade, sewage analysis has become a prevalent method of drug monitoring. However, traditional methods of detecting drugs in sewage are cumbersome, and rapid detection methods are relatively lacking. To address this, an innovative OPRM1-SNAP-tag/CMC method to directly identify drug components in sewage was established. Cell membrane chromatography (CMC) is an affinity chromatography technique which effectively detects receptor affinity substances. Cells constructed with high expression of specific receptor could be used to screen for compounds acting on the receptor. CMC based on OPRM1 provides a potentially convenient and effective tool for the detection of targeted drug components in sewage. In this study, the selectivity, reproducibility, column lifetime, and carryover of the CMC column had been assessed. Initially, we eluted the collected domestic sewage with methanol and acetonitrile, and the retention peaks were observed on the CMC system. Subsequently, without any preliminary sample preparation, we directly injected filtered samples of suspicious sewage into the OPRM1-SNAP-tag/CMC system, where we observed retention peaks as well. The retained components were further identified as morphine by using UPLC-MS/MS. In conclusion, the OPRM1-SNAP-tag/CMC method stands out as a reliable and robust model for the detection of drug components in sewage. It provides a valuable analytical tool for frontline drug control efforts, enhancing our capacity to monitor and mitigate the impact of drug abuse on society.

Unveil the toxicity induced on early life stages of zebrafish (Danio rerio) exposed to 3,4-methylenedioxymethamphetamine (MDMA) and its enantiomers

The increased detection of the recreational drug 3,4-methylenedioxymethamphetamine (MDMA) in aquatic ecosystems, has raised concern worldwide about its possible negative impacts on wildlife. MDMA is produced as racemate but its enantioselective effects on non-target organisms are poorly understood. Therefore, this study aimed to provide a comprehensive study of the toxicity of MDMA and its enantiomers in the early life stages of zebrafish (Danio rerio). Zebrafish embryos (≈3 h post fertilization) were exposed to different concentrations (0.02, 0.2, 2, 20, and 200 μg/L) of (R,S)-MDMA and both pure enantiomers. Both enantiomers induced effects on embryonic development, DNA integrity, and behaviour and enantioselective effects were noted. (S)-MDMA exhibits higher toxic effects on embryonic development level with increased mortality and severity of teratogenic effects, and behavioural abnormalities in acoustic startle-habituation response. (R)-MDMA affected general activity and avoidance behaviour, showing greater inhibitory effects on behavioural activity. Additionally, (R,S)-MDMA induced higher genotoxic effects than the two isolated enantiomers. These results are of concern at populational levels since effects on mortality, development, and behaviour were observed even at environmentally relevant concentrations, which can cause a reduction of larval viability and in the number of individuals in each generation, and an increase in the risk of predation of the organisms. Yet, the bioaccumulation studies showed that MDMA is not accumulated in zebrafish. Therefore, this work demonstrated for the first time the occurrence of MDMA enantiotoxicity in the early life stages of zebrafish, which should be considered in further environmental risk assessments involving fish species or other non-target aquatic organisms.

Enhanced removal of PPCPs and antibiotic resistance genes in saline wastewater using a bioelectrochemical-constructed wetland system

Pharmaceuticals and personal care products (PPCPs) are insufficiently degraded in saline wastewater treatment processes and are found at high concentrations and detection frequencies in aquatic environments. In this study, the wetland plant Thalia dealbata was selected using a screening plant experiment to ensure good salt tolerance and high efficiency in removing PPCPs. An electric integrated vertical-flow constructed wetland (E-VFCW) was developed to improve the removal of PPCPs and reduce the abundance of antibiotic resistance genes (ARGs). The removal efficiency of ofloxacin, enrofloxacin, and diclofenac in the system with anaerobic cathodic and aerobic anodic chambers is higher than that of the control system (41.84 ± 2.88%, 47.29 ± 3.01%, 53.29 ± 2.54%) by approximately 20.31%, 16.04%, and 35.25%. The removal efficiency of ibuprofen in the system with the aerobic anodic and anaerobic cathodic chamber was 28.51% higher than that of the control system (72.41 ± 3.06%) and promotes the reduction of ARGs. Electrical stimulation can increase the activity of plant enzymes, increasing their adaptability to stress caused by PPCPs, and PPCPs are transferred to plants. Species related to PPCPs biodegradation (Geobacter, Lactococcus, Hydrogenophaga, and Nitrospira) were enriched in the anodic and cathodic chambers of the system. This study provides an essential reference for the removal of PPCPs in saline-constructed wetlands.

Effect of secondary and tertiary wastewater treatment methods on opioids and the subsequent environmental impact of effluent and biosolids

Opioids are widely distributed, potent prescription analgesics that are known to be diverted for illicit use. Their prevalence of use is reflected by high concentrations of parent compounds and/or metabolites found in samples collected from wastewater treatment plants. Given that treatment byproducts enter the environment through several routes, the consequences of insufficient removal by treatment methods include unwanted environmental exposure and potential to disrupt ecosystems. Activated sludge treatment has been widely investigated for a large suite of prescription opioids but the same cannot be said for UV and chlorination. Additionally, the biosolid cycle of opioids has been overlooked previously. This study aimed to determine the extent to which secondary and tertiary wastewater treatment methods remove opioids from influent, and the associated environmental exposure for those persistent, as well as the fate of opioids in biosolids. Membrane bioreactor treatment proved effective for natural and semi-synthetic opioids while the effect of UV treatment was negligible. Chlorination was the most effective treatment method resulting in effluent with concentrations below theoretical predicted no-effect concentration. Biosolids are not subjected to any additional biological or chemical treatment after membrane bioreactor treatment and the levels detected in biosolid used as fertiliser had several opioids at potentially hazardous concentrations, indicated by a QSAR theoretical model. This data indicates a potential issue regarding the treatment process of biosolids and reliance on chlorination for effluent treatment that should be investigated in other treatment plants.

Daphnia magna an emerging environmental model of neuro and cardiotoxicity of illicit drugs

Cocaine, methamphetamine, ectasy (3,4-methylenedioxy amphetamine (MDMA)) and ketamine are among the most consumed drugs worldwide causing cognitive, oxidative stress and cardiovascular problems in humans. Residue levels of these drugs and their transformation products may still enter the aquatic environment, where concentrations up to hundreds of ng/L have been measured. In the present work we tested the hypothesis that psychotropic effects and the mode of action of these drugs in D. magna cognitive, oxidative stress and cardiovascular responses are equivalent to those reported in humans and other vertebrate models. Accordingly we expose D. magna juveniles to pharmacological and environmental relevant concentrations. The study was complemented with the measurement of the main neurotransmitters involved in the known mechanisms of action of these drugs in mammals and physiological relevant amino acids. Behavioural cognitive patters clearly differentiate the 3 psychostimulant drugs (methamphetamine, cocaine, MDMA) from the dissociative one ketamine. Psychostimulant drugs at pharmacological doses (10-200 μM), increased basal locomotion activities and responses to light, and decreased habituation to it. Ketamine only increased habituation to light. The four drugs enhanced the production of reactive oxygen species in a concentration related manner, and at moderate concentrations (10-60 μM) increased heartbeats, diminishing them at high doses (200 μM). In chronic exposures to environmental low concentrations (10-1000 ng/L) the four drugs did not affect any of the behavioural responses measured but methamphetamine and cocaine inhibited reproduction at 10 ng/L. Observed effects on neurotransmitters and related metabolites were in concern with reported responses in mammalian and other vertebrate models: cocaine and MDMA enhanced dopamine and serotonin levels, respectively, methamphetamine and MDMA decreased dopamine and octopamine, and all but MDMA decreased 3 MT levels. Drug effects on the concentration of up to 10 amino acids evidence disruptive effects on neurotransmitter synthesis, the urea cycle, lipid metabolism and cardiac function.

Core-Labeled Reverse Micelle-Based Supramolecular Solvents for Assisted Quick and Sensitive Determination of Amitriptyline in Wastewater

In recent years, the issue of pharmaceutical contaminants in water bodies has emerged as a significant environmental concern owing to the potential negative impacts on both aquatic ecosystems and human health. Consequently, the development of efficient and eco-friendly methods for their determination and removal is of paramount importance. In this context, the development of a surfactant ensemble sensor has been explored for hard-to-sense amphiphilic drug, i.e., amitriptyline. Herein, a pyrene-based amphiphile chemoreceptor was synthesized and characterized through various spectroscopic techniques such as 1H, 13C NMR, single-crystal XRD, FTIR, and ES-mass spectrometry. Then, dodecanoic acid (DA) and a pyrene-based receptor in a THF/water solvent system were used to generate reverse micelle-based self-aggregates of SUPRAS (SUPRAmolecular Solvent). The structural aspects, such as morphology and size, along with the stability of the SUPRAS aggregates were unfolded through spectroscopic and microscopic insights. The present investigation describes a synergistic approach that combines the unique properties of premicellar concentration of supramolecular solvent with the promising potential of pyrene-based receptor for enhanced amitriptyline extraction with simultaneous determination from water (LOD = 12 nM). To evaluate the effectiveness of the developed aggregates in real-world scenarios, experiments were conducted to determine the sensing efficiency among various pharmaceutical pollutants commonly found in water sources. The results reveal that the synergistic nanoensemble exhibits remarkable sensing ability, toward the amitriptyline (AMT) drug outperforming conventional methods.

The environmental occurrence, fate, and risks of 25 endocrine disruptors in Slovenian waters

Natural hormones, synthetic steroids and bisphenols are among the most active endocrine disruptors (EDs) in the aquatic environment, with great potential for causing adverse effects in aquatic organisms and humans. In this study, a focused group of 25 potent estrogenic and other ED compounds were simultaneously measured in wastewaters (WWs) and receiving surface waters (SWs) before and after wastewater treatment plants (WWTPs), where their removal efficiency was also estimated. Up to 16 of 25 EDs were successfully quantified in SWs and WWs, with bisphenols BPS, BPA, and BPF together with estriol and chlormadinone being the most prevalent with the highest measured concentrations of up to 35 μg/L in WWs and 400 ng/L in SWs. High load and insufficient removal of these substances by WWTPs lead to a significant increase in their concentrations in the receiving SWs downstream, while other sources could be responsible for an important portion of river contamination with EDs. Removal efficiency was very good for most EDs, although only from 0 to 44 % for E2, which shows a need for the improvement of current removal techniques. E2 and EE2 contribute the most to the alarmingly high risks of the total ED estrogenic potential, with the value increased by 36 % in SWs downstream from WWTPs, and the RQ value for the total estrogenic potential in individual SW samples being three orders of magnitude higher than that representing high risk. An additional comprehensive multi-parameter risk assessment determined high risk quotient and priority index values for BPA, E2, BPS and E1 with values of up to 450 in SWs. Our results show a focused insight into the risks associated with an important group of EDs and the role of WWTPs, while further highlighting the importance of regular monitoring of the environmental occurrence and risks of a focused range of EDs.

Retrospective spatiotemporal study of antidepressants in Slovenian wastewaters

This study utilizes wastewater-based epidemiology (WBE) to evaluate spatiotemporal changes in the consumption of antidepressants before and during the COVID-19 pandemic in Slovenia. Composite 24-h influent wastewater samples (n = 210) were collected from six wastewater treatment plants between summer 2019 and spring 2021. The samples were extracted using 96-well solid-phase extraction and analysed by liquid chromatography-tandem mass spectrometry. The measured concentrations of target antidepressant biomarkers were then converted to population-normalised mass loads (PNMLs), taking into account flow rate and catchment population. Ten biomarkers, including amitriptyline, bupropion, bupropion-OH, citalopram, norcitalopram, normirtazapine, venlafaxine, O-desmethylvenlafaxine, trazodone, and moclobemide, were above the lower limit of quantification and were included in the spatiotemporal temporal assessment. The highest PNMLs were detected for O-desmethylvenlafaxine (mean ± SD: 82.1 ± 21.2 mg/day/1000 inhabitants) and venlafaxine (38.0 ± 10.6 mg/day/1000 inhabitants), followed by citalopram (27.0 ± 10.7 mg/day/1000 inhabitants). In addition, the mean metabolite/parent compound ratios were comparable with other WBE studies indicating consumption rather than direct disposal. Overall, the results indicated significant spatiotemporal variations depending on the location, and the PNMLs of most biomarkers increased during the first wave of the COVID-19 pandemic (spring of 2020). However, no clear spatial patterns were revealed related to the pandemic.

Screening for new psychoactive substances in wastewater from educational institutions

Drug (ab)use among young people is a serious issue, negatively impacting their well-being and prospects. The emergence of new psychoactive substances (NPS) further complicates the situation as they are easily accessible (e.g., online), but users are at high risk of intoxication as their chemical identity is often unknown and toxicity poorly understood. While surveys and drug testing are traditionally used in educational institutions to comprehend drug use trends and establish effective prevention programs, they are not without their limitations. Accordingly, we investigated the occurrence of NPS in educational institutions through wastewater analysis and critically evaluated the viability of the approach. The study included eight wastewater samples from primary schools (ages 6-15 years), six from secondary schools (ages 15-19 years), three from institutions for both secondary and higher education (ages 15+), and six from higher educational institutions (ages 19+). Samples were obtained mid-week and evaluated in two Slovenian municipalities; the capital Ljubljana and a smaller one (M1). Samples were screened using liquid chromatography-ion mobility-high-resolution mass spectrometry (LC-IMS-HRMS), and NPS identified at three levels of confidence (Level 1: unequivocal, Level 2: probable, Level 3: tentative) from a suspect list containing over 5600 entries. NPS were identified in all types of educational institutions. Most were synthetic stimulants, with 3-MMC, ephedrine, 4-chloro-α-PPP, and ethcathinone being unequivocally identified. Also, NPS were present in wastewater from all educational institution types revealing potential spatial but no inter-institutional trends. Although specific groups cannot be targeted, the study, as a proof-of-concept, demonstrates that a suspect screening of wastewater employing LC-IMS-HRMS can be used as a radar for NPS in educational institutions and potentially replace invasive drug testing.

Occurrence and removal rate of typical pharmaceuticals and personal care products (PPCPs) in an urban wastewater treatment plant in Beijing, China

The occurrence and removal rate of 52 typical pharmaceuticals and personal care products (PPCPs) were investigated in a wastewater treatment plant in Beijing, China. Thirty-three PPCPs were found in the influent, with caffeine (CF, 11387.0 ng L-1) being the most abundant, followed by N,N-diethyl-meta-toluamide (DEET, 9568.4 ng L-1), metoprolol (MTP, 930.2 ng L-1), and diclofenac (DF, 710.3 ng L-1). After treatment processes, the cumulative concentration of PPCPs decreased from 2.54 × 104 ng L-1 to 1.44 × 103 ng L-1, with the overall removal efficiency (RE) of 94.3%. Different treatment processes showed varying contributions in removing PPCPs. PPCPs were efficiently removed in sedimentation, anoxic, and ultraviolet units. For individual compounds, a great variation in RE (52.1-100%) was observed. Twenty-two PPCPs were removed by more than 90%. The highly detected PPCPs in the influent were almost completely removed. Aerated grit chamber removed nearly 50% of fluoroquinolone (FQs) and more than 60% of sulfonamides. Most PPCPs showed low or negative removals during anaerobic treatment, except for CF which was eliminated by 64.9%. Anoxic treatment demonstrated positive removals for most PPCPs, with the exceptions of DF, MTP, bisoprolol, carbamazepine (CBZ), and sibutramine. DEET and bezafibrate were efficiently removed during the secondary sedimentation. Denitrification biological filter and membrane filtration also showed positive effect on most PPCPs removals. The remaining compounds were oxidized by 16-100% in ozonation. DF, sulpiride, ofloxacin (OFL), trimethoprim, and phenolphthalein were not amenable to ultraviolet. After the treatment, the residue OFL, CBZ, and CF in receiving water were identified to pose high risk to aquatic organisms. Considering the complex mixtures emitted into the environment, therapeutic groups psychotropics, stimulant, and FQs were classified as high risk. These findings provide valuable insights into adopting appropriate measures for more efficient PPCPs removals, and emphasize the importance of continued monitoring specific PPCPs and mixtures thereof to safeguard the ecosystem.

In five wastewater treatment plants in Xinjiang, China: Removal processes for illicit drugs, their occurrence in receiving river waters, and ecological risk assessment

Residues of illicit drugs are frequently detected in wastewater, but data on their removal efficiency by wastewater treatment plants (WWTPs) and the ecological risks to the aquatic environment are lacking in this study. The research evaluates the residues, mass load, drug removal efficiency, and risk assessment of illicit drugs in WWTPs and aquatic environments (lakes) in Xinjiang, China. Initially, the concentration (incidence) and mass load of 10 selected illicit drugs were analyzed through wastewater analysis. The detected substances included methamphetamine (METH), morphine (MOR), 3,4-methylenedioxy methamphetamine (MDMA), methadone (MTD), cocaine (COC), benzoylecgonine (BE), ketamine (KET), and codeine (COD), with concentrations ranging from 0.11 ± 0.01 ng/L (methadone) to 48.26 ± 25.05 ng/L (morphine). Notably, morphine (59.74 ± 5.82 g/day) and methamphetamine (41.81 ± 4.91 g/day) contributed significantly to the WWTPs. Next, the drug removal efficiency by different sewage treatment processes was ranked as follows: Anaerobic-Oxic (A/O) combined Membrane Bio-Reactor (MBR) treatment process > Oxidation ditch treatment process > Anaerobic-Anoxic-Oxic (A2/O) treatment process > Anaerobic-Anoxic-Oxic combined Membrane Bio-Reactor treatment process. Finally, the research reviewed the concentration and toxicity assessments of these substances in the aquatic environment (lakes). The results indicated that Lake1 presented a medium risk level concerning the impact of illicit drugs on the aquatic environment, whereas the other lakes exhibited a low risk level. As a result, it is recommended to conduct long-term monitoring and source analysis of illicit drugs, specifically in Lake1, for further investigation. In conclusion, to enhance the understanding of the effects of illicit drugs on the environment, future research should expand the list of target analytes.

Dynamics of drug contamination of the river-water in the rural, semirural and urban areas of the Mrežnica River in Croatia during COVID-19 pandemic (2020-2021)

Increased contamination of aquatic ecosystems with pharmaceuticals could have been expected due to the COVID-19 pandemic. Surface water from three domains (rural, semirural, urban) of the Mrežnica River (Croatia) was screened for 253 pharmaceuticals by SPE-UHPLC-MS/MS. At the beginning of the pandemic, the highest concentration of drugs (excluding veterinary) was detected at urban site (291.4 ng/L), followed by semirural (186.5 ng/L) and rural (141.6 ng/L). With the progression of pandemic, contamination increase was observed at all sites, but it was the most obvious at semirural (approximately 400-700 ng/L). The most pronounced concentration increases were observed for non-opioid analgesics, especially ibuprofen. In September 2021, the first notable occurrence of opioid analgesics was recorded. The most represented group of pharmaceuticals at the start of the pandemic (May 2020) was generally stimulants (caffeine, cotinine). In September 2021, the predominant group was analgesics at all sites (45-84%), whereas stimulants decreased to undetectable levels. The results of this study indicated that the epidemiological measures and medical treatments that were widely imposed/applied caused notable increase of the surface water contamination with drugs of a small river with limited dilution capacity, indirectly pointing to the changes that occurred in the behaviour and habits of the inhabitants of the affected areas.

Chitosan Hydrogels for Water Purification Applications

Chitosan-based hydrogels have gained significant attention for their potential applications in water treatment and purification due to their remarkable properties such as bioavailability, biocompatibility, biodegradability, environmental friendliness, high pollutants adsorption capacity, and water adsorption capacity. This article comprehensively reviews recent advances in chitosan-based hydrogel materials for water purification applications. The synthesis methods, structural properties, and water purification performance of chitosan-based hydrogels are critically analyzed. The incorporation of various nanomaterials into chitosan-based hydrogels, such as nanoparticles, graphene, and metal-organic frameworks, has been explored to enhance their performance. The mechanisms of water purification, including adsorption, filtration, and antimicrobial activity, are also discussed in detail. The potential of chitosan-based hydrogels for the removal of pollutants, such as heavy metals, organic contaminants, and microorganisms, from water sources is highlighted. Moreover, the challenges and future perspectives of chitosan-based hydrogels in water treatment and water purification applications are also illustrated. Overall, this article provides valuable insights into the current state of the art regarding chitosan-based hydrogels for water purification applications and highlights their potential for addressing global water pollution challenges.

Occurrence and sources of residues of drugs of abuse in an urban aquifer: Chemical analysis and solute transport modelling

This study investigated the occurrence and potential sources of residues of drugs of abuse in an urban aquifer beneath the City of Ljubljana using water analysis and a solute transport model designed to predict nitrogen distribution. Samples were collected from three sources: 28 wastewater samples (24-h composites), 4 aquifer-recharging river samples (grab), and 22 groundwater samples. The samples were analysed for residues of commonly (ab)used licit drugs (nicotine and alcohol), medications of abuse (morphine, methadone, codeine, and ketamine), and illicit drugs (tetrahydrocannabinol - THC, cocaine, amphetamines, and heroin) using liquid-liquid (alcohol residue) and solid-phase extraction, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Additionally, we used solute transport modelling to predict the spatial distribution of drug residues in the aquifer and their potential sources. Nicotine (up to 45,7 ng/L), cotinine (up to 5.86 ng/L), trans-3'-hydroxycotinine (up to 0.528 ng/L) and benzoylecgonine (up to 0.572 ng/L) were the most commonly detected drug residues in groundwater, followed by cocaine (<LOQ). In comparison, methadone (0.054 ng/L) was detected only once. A higher prevalence of residues of drugs of abuse was observed in samples obtained at the south-eastern edge of the aquifer, downgradient from the main zone of urbanisation, agreeing with model predictions. Although drug residues were detected in river water, modelling suggests that the city's leaky sewer system is the primary source of drug residues.