Multi-residue ultra-performance liquid chromatography coupled with tandem mass spectrometry method for comprehensive multi-class anthropogenic compounds of emerging concern analysis in a catchment-based exposure-driven study.

This paper presents a new multi-residue method for the quantification of more than 142 anthropogenic compounds of emerging concern (CECs) in various environmental matrices. These CECs are from a wide range of major classes including pharmaceuticals, household, industrial and agricultural. This method utilises ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) for analysis of five matrices (three liquid and two solid) from wastewater treatment processes and the surrounding environment. Relative recoveries were predominantly between 80 and 120%; however, due to the complexity of the matrices used in this work, not all compounds were recovered in all matrices, from 138/142 analytes in surface water to 96/142 analytes in digested solids. Method quantification limits (MQLs) ranged from 0.004 ng L-1 (bisoprolol in surface water) to 3118 ng L-1 (creatinine in wastewater treatment work (WwTW) influent). The overall method accuracy was 107.0%, and precision was 13.4%. To test its performance, the method was applied to the range of environmental matrices at WwTWs in South West England. Overall, this method was found to be suitable for application in catchment-based exposure-driven studies, as, of the total number of analytes quantifiable in each matrix, 61% on average was found to be above their corresponding MQL. The results confirm the need for analysing both the liquid and solid compartments within a WwTW to prevent under-reporting of concentrations.

New Framework To Diagnose the Direct Disposal of Prescribed Drugs in Wastewater - A Case Study of the Antidepressant Fluoxetine.

Intentional or accidental release (direct disposal) of high loads of unused pharmaceuticals into wastewater can go unnoticed. Here, direct disposal of a pharmaceutical drug via the sewer network was identified for the first time using wastewater analysis. An irregularly high load of the antidepressant fluoxetine in raw wastewater (10.5 ± 2.4 g d(-1)) was up to 11 times greater than any other day. National prescription data revealed a predicted daily fluoxetine load for the studied treatment works to be 0.4-1.6 g d(-1). Enantio-selective analysis showed the high load of fluoxetine was present as a racemic mixture, which is typical for fluoxetine in dispensed formulations. As fluoxetine undergoes stereoselective metabolism within the body, a racemic mixture in wastewater suggests a nonconsumed drug was the major contributor of the high load. This was confirmed by its major metabolite norfluoxetine whose load did not increase on this day. Considering the most commonly prescribed formulation of fluoxetine, this increased load accounts for the disposal of ∼915 capsules. Furthermore, as fluoxetine is prescribed as one capsule per day, disposal is unlikely to be at the patient level. It is postulated that direct disposal was from a facility which handles larger quantities of the drug (e.g., a pharmacy).

In Situ Calibration of a New Chemcatcher Configuration for the Determination of Polar Organic Micropollutants in Wastewater Effluent.

Passive sampling is proposed as an alternative to traditional grab- and composite-sampling modes. Investigated here is a novel passive sampler configuration, the Chemcatcher containing an Atlantic HLB disk covered by a 0.2 µm poly(ether sulfone) membrane, for monitoring polar organic micropollutants (personal care products, pharmaceuticals, and illicit drugs) in wastewater effluent. In situ calibration showed linear uptake for the majority of detected micropollutants over 9 days of deployment. Sampling rates (RS) were determined for 59 compounds and were generally in the range of 0.01-0.10 L day(-1). The Chemcatcher was also suitable for collecting chiral micropollutants and maintaining their enantiomeric distribution during deployment. This is essential for their future use in developing more accurate environmental risk assessments at the enantiomeric level. Application of calibration data in a subsequent monitoring study showed that the concentration estimated for 92% of micropollutants was within a factor of 2 of the known concentration. However, their application in a legislative context will require further understanding of the properties and mechanisms controlling micropollutant uptake to improve the accuracy of reported concentrations.

Targeted multi-analyte UHPLC-MS/MS methodology for emerging contaminants in septic tank wastewater, sludge and receiving surface water.

Septic tanks treat wastewater of individual houses and small communities (up to 2000 people in Scotland) in rural and semi-urban areas and are understudied sources of surface water contamination. A multi-analyte methodology with solid phase extraction (SPE), ultra-sonic extraction, and direct injection sample preparation methods was developed to analyse a comprehensive range of emerging contaminants (ECs) including prescription and over-the-counter pharmaceuticals and related metabolites, natural and synthetic hormones, and other human wastewater marker compounds in septic tank influent and effluent, river water, suspended solids, and septic tank sludge by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The number of quantifiable compounds in each matrix varied from 68 in septic tank wastewater to 59 in sludge illustrating its applicability across a range of matrices. Method quantification limits were 2.9 × 10-5-1.2 µg L-1 in septic tank influent, effluent and river water, with ≤0.01 µg L-1 achieved for 60% of ECs in all three water matrices, and 0.080-49 µg kg-1 in sludge. The developed method was applied to a septic tank (292 population equivalents) and the receiving river in the North-East of Scotland. Across all samples analysed, 43 of 68 ECs were detected in at least one matrix, demonstrating the method's sensitivity. The effluent concentrations suggest limited removal of ECs in septic tanks and a potential impact to river water quality for some ECs. However, further monitoring is required to better appreciate this. The developed methodology for a wide variety of ECs in a range of liquid and solid phases will allow, for the first time, a comprehensive assessment of ECs fate and removal in septic tanks, and their impact to surface water quality.

The determination of nonylphenol and its precursors in a trickling filter wastewater treatment process.

An ultra performance liquid chromatography method coupled to a triple quadrupole mass spectrometer was developed to determine nonylphenol and 15 of its possible precursors (nonylphenol ethoxylates and nonylphenol carboxylates) in aqueous and particulate wastewater matrices. Final effluent method detection limits for all compounds ranged from 1.4 to 17.4 ng l(-1) in aqueous phases and from 1.4 to 39.4 ng g(-1) in particulate phases of samples. The method was used to measure the performance of a trickling filter wastewater treatment works, which are not routinely monitored despite their extensive usage. Relatively good removals of nonylphenol were observed over the biological secondary treatment process, accounting for a 53 % reduction. However, only an 8 % reduction in total nonylphenolic compound load was observed. This was explained by a shortening in ethoxylate chain length which initiated production of shorter polyethoxylates ranging from 1 to 4 ethoxylate units in length in final effluents. Modelling the possible impact of trickling filter discharge demonstrated that the nonylphenol environmental quality standard may be exceeded in receiving waters with low dilution ratios. In addition, there is a possibility that the EQS can be exceeded several kilometres downstream of the mixing zone due to the biotransformation of readily degradable short-chained precursors. This accentuates the need to monitor 'non-priority' parent compounds in wastewater treatment works since monitoring nonylphenol alone can give a false indication of process performance. It is thus recommended that future process performance monitoring and optimisation is undertaken using the full suite of nonylphenolic moieties which this method can facilitate.

Influence of solids and hydraulic retention times on microbial diversity and removal of estrogens and nonylphenols in a pilot-scale activated sludge plant.

The removal of EDCs in activated sludge processes can be enhanced by increasing solid and hydraulic retention times (SRT and HRT); it has been suggested that the improvement in removal is due to changes in microbial community structure (MCS). Though the influence of SRT and HRT on chemical removal and MCS has been studied in isolation, their synergistic impact on MCS and the removal of estrogens and nonylphenols in activated sludge remains unknown. Hence, we investigated how both parameters influence MCS in activated sludge processes and their ulterior effect on EDC removal. In our study, an activated sludge pilot-plant was fed with domestic sewage fortified with 100 and 1000 ng/L nonylphenols or 2 and 15 ng/L estrogens and operated at 3, 10 and 27 d SRT (constant HRT) and at 8, 16 and 24 h HRT (constant SRT). The MCS was assessed by phospholipid fatty acids (PLFA) analysis, and the archaeal and bacterial diversities were determined by 16S rRNA analysis. From the PLFA, the microbial abundance ranked as follows: Gram-negative > fungi > Gram-positive > actinomycetes whilst 16S rRNA analysis revealed Proteobacteria > Bacteroidetes > Others. Both PLFA and 16S rRNA analysis detected changes in MCS as SRT and HRT were increased. An SRT increment from 3 to 10 d resulted in higher estrone (E1) removal from 19 to 93% and nonylphenol-4-exthoxylate (NP4EO) from 44 to 73%. These findings demonstrate that EDC-removal in activated sludge plants can be optimised where longer SRT (>10 d) and HRT (>8 h) are suitable. We have also demonstrated that PLFA can be used for routine monitoring of changes in MCS in activated sludge plants.

Occurrence and fate of chiral and achiral drugs in estuarine water - a case study of the Clyde Estuary, Scotland.

There is currently a lack of enantiospecific studies on chiral drugs in estuarine environments. In this study, the occurrence and fate of 20 prescription and illicit drugs, metabolites and associated contaminants were investigated in the Clyde Estuary, Scotland, over a 6 month period. More than half of the drugs were detected in at least 50% of water samples collected (n = 30), with considerable enantiomer enrichment observed for some of the compounds. Enantiomeric fraction (EF) values of the chiral drugs investigated in this study ranged from <0.03 for amphetamine to 0.70 for bisoprolol. Microcosm studies revealed enantioselective degradation of fluoxetine and citalopram for the first-time in estuarine waters (over 14 days at 8.0 °C in water of 27.8 practical salinity units). Interestingly, fish collected from the inner estuary (Platichthys flesus - European flounder) contained drug enantiomers in muscle and liver tissues. This included propranolol, fluoxetine, citalopram, and venlafaxine. Considerable enantiospecific differences were observed between the two fish tissues, and between fish tissues and water samples. For example, citalopram EF values in muscle and liver were 0.29 ± 0.03 and 0.18 ± 0.01, respectively. In water samples EF values were in the range 0.36-0.49. This suggests enantioselective metabolism of citalopram by P. flesus. The enantioselectivity of drugs observed within the Clyde Estuary highlights the need for enantiospecific effect-driven studies on marine organisms to better understand their impact in estuarine environments, contributing to the likely cumulative impacts of the range of contaminants to which marine coastal wildlife is exposed.

Polyamide microplastics in wastewater as vectors of cationic pharmaceutical drugs.

Reported here is the first study to investigate the adsorption of pharmaceutical drugs to microplastics in wastewater. Wastewater is an environmental source of microplastics and pharmaceuticals, which is discharged as treated effluent or combined sewer overflows. In this study, adsorption of cationic pharmaceuticals, with a range of octanol-water distribution coefficients, to polyamide (Nylon 12) microplastics was investigated in real wastewater samples. Significant adsorption was observed for the more hydrophobic pharmaceuticals studied, propranolol, amitriptyline, and fluoxetine, with equilibrium reached within 24 h. Microplastic-wastewater distribution coefficients for these three pharmaceuticals were 191, 749 and 1020 L kg-1, respectively. Favourable wastewater conditions for adsorption of pharmaceuticals to polyamide were at pH > 7, summer temperatures (20 °C), and no stormwater dilution. Adsorption of the more hydrophilic pharmaceuticals atenolol, pseudoephedrine, metoprolol, and tramadol was ≤7% under all conditions and considered insignificant. Limited desorption (7-17%) of propranolol, amitriptyline, and fluoxetine was observed in river water over 24 h. This suggests that microplastics may be able to transport adsorbed pharmaceuticals for considerable distances after discharge. In simulated gastric fluids their desorption increased to 24-27% and 40-58% in cold- and warm-blooded temperatures respectively. The findings demonstrate that wastewater microplastics could act as a vector of pharmaceutical drugs, from wastewater treatment plants to aquatic organisms. However, further research is needed to better appreciate the risks posed by pharmaceuticals adsorbed to microplastics in comparison to other organic particulates found in wastewater.

Adsorption of a diverse range of pharmaceuticals to polyethylene microplastics in wastewater and their desorption in environmental matrices.

It is proposed that microplastics discharged from wastewater treatment plants act as a vector of pharmaceuticals. In this study, adsorption of pharmaceuticals to polyethylene microplastics was investigated in municipal wastewater. Pharmaceuticals for study were selected to represent different speciation (anionic, cationic, and neutral) and a range of pH dependant octanol-water distribution coefficients (log DOW). Findings revealed adsorption favoured those in cationic form with the greatest hydrophobicity (e.g., fluoxetine log DOW 2.0 at pH 7.8). Adsorption of anionic pharmaceuticals was restricted due to repulsion with the microplastic's negatively charged surface. Only atorvastatin had any appreciable adsorption due to its comparatively high log DOW value (2.9). Those pharmaceuticals predominantly in neutral form (carbamazepine and ketamine) with log DOW values ≥2.4 had similar adsorption. Freundlich KF values were 3400, 386, 284, 259 and 218 (mg kg-1)(mg L-1)1/n for fluoxetine, propranolol, atorvastatin, ketamine, and carbamazepine, respectively. All pharmaceuticals with log DOW values <1.0 (atenolol, gliclazide, bezafibrate, and ifosfamide) did not adsorb to microplastics, irrespective of their speciation. Changing composition of wastewater (pH, dilution with stormwater and NaCl addition) within the range expected for municipal wastewater had limited influence on adsorption. Pharmaceutical desorption from microplastics was assessed in river water and simulated gastric and intestinal fluids. Solution pH was considered the most important factor for pharmaceutical desorption, influencing both pharmaceutical speciation and microplastic surface charge. Greatest desorption was observed for the cationic pharmaceuticals in gastric fluids due to a reduced surface charge of the microplastics under low pH conditions. Up to 50% desorption of fluoxetine occurred in gastric fluid at 37 °C. These findings show that pharmaceuticals adsorbed to microplastics are 'bioavailable'. However, this is often overlooked as an exposure route to aquatic organisms because water samples are normally pre-filtered prior to chemical analysis.

A review of combined sewer overflows as a source of wastewater-derived emerging contaminants in the environment and their management.

Emerging contaminants such as pharmaceuticals, illicit drugs and personal care products can be released to the environment in untreated wastewater/stormwater mixtures following storm events. The frequency and intensity of combined sewer overflows (CSOs) has increased in some areas due to increasing urbanisation and climate change. Therefore, this review provides an up-to-date overview on CSOs as an environmental source of emerging contaminants. Other than compounds with high removal, those chiral species subject to enantioselective changes (i.e. degradation or inversion) during wastewater treatment can be effective markers of CSO discharge in the environment. A proposed framework for the selection of emerging contaminants as markers of CSOs is outlined. Studies have demonstrated that CSOs can be the main source of emerging contaminants with high removal efficiency during wastewater treatment (e.g. > 90%). However, the impact of CSOs on the environment is location specific and requires decision-making on their appropriate management at catchment level. This process would be aided by further studies on CSOs which incorporate the monitoring of emerging contaminants and their effects in the environment with those more routinely monitored pollutants (e.g. pathogens and priority substances). Mitigation and treatment strategies for emerging contaminants in CSOs are also discussed.

Micropollutant fluxes in urban environment - A catchment perspective.

This study provided a holistic understanding of the sources, fate and behaviour of 142 compounds of emerging concern (CECs) throughout a river catchment impacted by 5 major urban areas. Of the incoming 169.3 kg d-1 of CECs entering the WwTWs, 167.9 kg d-1 were present in the liquid phase of influent and 1.4 kg d-1 were present in the solid phase (solid particulate matter, SPM). Analysis of SPM was important to determine accurate loads of incoming antidepressants and antifungal compounds, which are primarily found in the solid phase. Furthermore, these classes and the plasticiser, bisphenol A (BPA) were the highest contributors to CEC load in digested solids. Population normalised loads showed little variation across the catchment at 154 ± 12 mg d-1 inhabitant-1 indicating that population size is the main driver of CECs in the studied catchment. Across the catchment 154.6 kg d-1 were removed from the liquid phase during treatment processes. CECs discharged into surface waters from individual WwTWs contributed between 0.19 kg d-1 at WwTW A to 7.3 kg d-1 at WwTW E, which correlated strongly with the respective contributing populations. Spatial and temporal variations of individual CECs and their respective classes were found in WwTW influent (both solid (influentSPM) and liquid phases (influentAQ)) throughout the catchment, showing that different urban areas impact the catchment in different ways, with key variables being lifestyle, use of over-the-counter pharmaceuticals and industrial activity. Understanding of both spatial and temporal variation of CECs at the catchment level helped to identify possible instances of direct disposal, as in the case of carbamazepine. Analysis of surface waters throughout the catchment showed increasing mass loads of CECs from upstream of WwTW A to downstream at WwTW D, showing clear individual contributions from WwTWs. Many CECs were ubiquitous throughout the river water in the catchment. Daily loads ranged from 0.005 g d-1 (ketamine, WwTW A) up to 1890.3 g d-1 (metformin, WwTW C) for the 84/138 CECs that were detected downstream of the WwTWs. For metformin this represents the equivalent of ∼1,890 tablets (1,000 mg per tablet) dissolved in the river water downstream of WwTW C.

Multi-residue enantioselective determination of emerging drug contaminants in seawater by solid phase extraction and liquid chromatography-tandem mass spectrometry.

This study proposes a new multi-residue enantioselective method for the determination of emerging drug contaminants in sea water by solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). To achieve satisfactory enantiomeric separation with a vancomycin stationary phase it was essential to limit sodium chloride in extracted samples to <1 µg per injection. This was achieved through a straightforward SPE method using a 50 mL water wash volume and analyte elution in acetonitrile. A Chiral-V enantioselective column (150 × 2.1 mm; 2.7 µm particle size) operated in polar ionic mode enabled simultaneous drug separations in 30 minutes. Analytes with enantioresolution ≥1 were the stimulants amphetamine and methamphetamine, the beta-agonist salbutamol, the beta-blockers propranolol, sotalol and acebutolol, the anti-depressants fluoxetine, venlafaxine, desmethylvenlafaxine and citalopram, and the antihistamine chlorpheniramine. Method quantitation limits were <10 ng L-1 and method trueness was 80-110% for most analytes. The method was applied to samples from the Forth and Clyde estuaries, Scotland. Chiral drugs were present at concentrations in the range 4-159 ng L-1 and several were in non-racemic form (enantiomeric fraction ≠ 0.50) demonstrating enantiomer enrichment. This emphasises the need for further enantiospecific drug exposure and effect studies in the marine environment.

Enantiospecific behaviour of chiral drugs in soil.

The importance of stereochemistry on the behaviour and effects of chiral pharmaceutical and illicit drugs in amended agricultural soils has been over looked to date. Therefore, this study was aimed at investigating the enantiospecific behaviour of a chemically diverse range of chiral drugs including naproxen, ibuprofen, salbutamol, bisoprolol, metoprolol, propranolol, acebutolol, atenolol, chlorpheniramine, amphetamine, fluoxetine and citalopram in soil microcosms. Considerable changes of the enantiomeric composition of ibuprofen, naproxen, atenolol, acebutolol and amphetamine were observed within 56 d. This is significant as enantiomer enrichment can favour the pharmacologically active (e.g., S(-)-atenolol) or less/non-active forms of the drug (e.g., R(-)-amphetamine). Single enantiomer microcosms showed enantiospecific degradation was responsible for enantiomer enrichment of atenolol and amphetamine. However, naproxen and ibuprofen enantiomers were subject to chiral inversion whereby one enantiomer converts to its antipode. Interestingly, chiral inversion was bidirectional and this is the first time it is reported in soil. Therefore, introduction of the less active enantiomer to soil through irrigation with reclaimed wastewater or biosolids as fertiliser can result in the formation of its active enantiomer, or vice versa. This phenomenon needs considered in risk assessment frameworks to avoid underestimating the risk posed by chiral drugs in amended soils.

(Fluoro)quinolones and quinolone resistance genes in the aquatic environment: A river catchment perspective.

This study provides an insight into the prevalence of (fluoro)quinolones (FQs) and their specific quinolone qnrS resistance gene in the Avon river catchment area receiving treated wastewater from 5 wastewater treatment plants (WWTPs), serving 1.5 million people and accounting for 75% of inhabitants living in the catchment area in the South West of England.. Ofloxacin, ciprofloxacin, nalidixic acid and norfloxacin were found to be ubiquitous with daily loads reaching a few hundred g/day in wastewater influent and tens of g/day in receiving waters. This was in contrast to other FQs analysed: flumequine, nadifloxacin, lomefloxacin, ulifloxacin, prulifloxacin, besifloxacin and moxifloxacin, which were hardly quantified. Enantiomeric profiling revealed that ofloxacin was enriched with the S-(-)-enantiomer, likely deriving from its prescription as the more potent enantiomerically pure levofloxacin, alongside racemic ofloxacin. While ofloxacin's enantiomeric fraction (EF) remained constant, high stereoselectivity was observed in the case of its metabolite ofloxacin-N-oxide. The removal efficiency of quinolones during wastewater treatment at 5 WWTPs utilising either trickling filters (TF) or activated sludge (AS), was compound and wastewater treatment process dependent, with AS providing better efficiency than TF. The qnrS resistance gene was ubiquitous in wastewater. Its removal was WWTP treatment process dependent with TF performing best and resulting in significant removal of the gene (from 28 to 75%). AS underperformed with only 9% removal in the case of activated sludge and actual increase in the gene copy number within sequencing batch reactors (SBRs). Interestingly, the data suggests that higher removal of antibiotics could be linked with high prevalence of the gene (SBR and WWTP E) and vice versa, low removal of antibiotic is correlated with lower prevalence of the gene in wastewater effluent (TF, WWTP B and D). This is especially prominent in the case of ofloxacin and could indicate that AS might be facilitating antimicrobial resistance (AMR) prevalence to higher extent than TF. Wastewater-based epidemiology (WBE) was also applied to monitor any potential misuse (e.g. direct disposal) of FQs in the catchment. In most cases higher use of antibiotics with respect to official statistics (i.e. ciprofloxacin, ofloxacin) was observed, which suggests that FQs management practice require further attention.

Enantioselective LC-MS/MS for anthropogenic markers of septic tank discharge.

Households in rural locations utilize septic tanks for wastewater treatment and can cause surface water contamination. A new methodology was developed to help investigate the role septic tanks play in the dissemination of prescription and over-the-counter drugs, personal care products and stimulants in the aqueous environment. Simultaneous analysis of 16 chiral and achiral anthropogenic markers was achieved using a Chirobiotic V2® enantioselective column in polar ionic mode. The optimized method achieved quantitation limits for 16 compounds in the range 0.001-2.9 µg L-1 and 0.0002-0.43 µg L-1 for septic tank effluent and stream water, respectively. Application of the method to samples collected in North East Scotland found caffeine to be ubiquitous in all samples studied suggesting it as a good indicator of septic tank discharge. In rural streams studied, concentrations of all prescription drugs investigated were ≤0.02 µg L-1. However, analgesics and stimulants were at high concentration in one location indicating direct discharge of septic tank wastewater (i.e., not dissipated through a soak away). For example, paracetamol, cotinine and caffeine were measured at 1100 µg L-1, 31 µg L-1 and 200 µg L-1, respectively, which is comparable to septic tank effluents. Furthermore, S(+)-amphetamine and R(-)-amphetamine were present in this stream sample at 0.20 and 0.27 µg L-1. This corresponds to an enantiomeric fraction of 0.43, which is typical of untreated wastewaters in the UK. Findings illustrate further study on the diffuse impact of septic tanks to surface water is needed and can be supported using this new multi-residue enantioselective method.

Assessment of bisphenol-A in the urban water cycle.

The plasticizer bisphenol-A (BPA) is common to municipal wastewaters and can exert toxicity to exposed organisms in the environment. Here BPA concentration at 5 sewage treatment works (STW) and distribution throughout a river catchment in South West UK were investigated. Sampling sites included influent and effluent wastewater (n = 5), river water (n = 7) and digested sludge (n = 2) which were monitored for 7 consecutive days. Findings revealed average BPA loads in influent wastewater at two STWs were 10-37 times greater than the other wastewaters monitored. Concentrations up to ~100 µg L-1 were measured considerably higher than previously reported for municipal wastewaters. Temporal variability throughout the week (i.e., highest concentrations during weekdays) suggests these high concentrations are linked with industrial activity. Despite ≥90% removal during wastewater treatment, notable concentrations remained in tested effluent (62-892 ng L-1). However, minimal impact on BPA concentrations in river water was observed for any of the effluents. The maximum BPA concentration found in river water was 117 ng L-1 which is considerably lower than the current predicted no effect concentration of 1.6 µg L-1. Nevertheless, analysis of digested sludge from sites which received these elevated BPA levels revealed average concentrations of 4.6 ±â€¯0.3 and 38.7 ±â€¯5.4 µg g-1. These sludge BPA concentrations are considerably greater than previously reported and are attributed to the high BPA loading in influent wastewater. A typical sludge application regime to agricultural land would result in a predicted BPA concentration of 297 ng g-1 in soil. Further studies are needed on the toxicological thresholds of exposed terrestrial organisms in amended soils to better assess the environmental risk here.

Estimation of community-wide exposure to bisphenol A via water fingerprinting.

Molecular epidemiology in human biomonitoring allows for verification of public exposure to chemical substances. Unfortunately, due to logistical difficulties and high cost, it evaluates only small study groups and as a result does not provide comprehensive large scale community-wide exposure data. Wastewater fingerprinting utilizing metabolic biomarkers of exposure that are excreted collectively by studied populations into urine and ultimately into the community's wastewater, provides a timely alternative to traditional approaches. This study aimed to provide comprehensive spatiotemporal community-wide exposure to bisphenol A (BPA, including BPA intake) using wastewater fingerprinting. Wastewater fingerprinting was undertaken using high resolution mass spectrometry retrospective data mining of characteristic BPA human metabolism marker (bisphenol A sulphate), applied to a large geographical area of 2000 km2 and a population of ~1.5 million served by 5 WWTPs (wastewater treatment plants) accounting for >75% of the overall population in the studied catchment. Community-wide BPA intake was found to be below temporary tolerable daily intake (t-TDI) level of 4 µg kg-1 day-1 set by the European Food Safety Agency (EFSA) suggesting overall low exposure at 3 WWTPs serving residential areas with low industrial/commercial presence. However, at two WWTPs serving communities with higher industrial/commercial presence, higher BPA sulphate loads corresponding to higher (up to 14 times) BPA intakes (exceeding 10 µg kg-1 day-1 at one WWTP and reaching 50 µg kg-1 day-1 at the second WWTP) were observed and they are likely linked with occupational exposure. Characteristic temporal variations of BPA intake were noted in most studied WWTPs with the lowest intake occurring during weekends and the highest during weekdays.

Stereoisomeric profiling of chiral pharmaceutically active compounds in wastewaters and the receiving environment - A catchment-scale and a laboratory study.

Chiral pharmaceutically active compounds (cPACs) are not currently governed by environmental regulation yet are expected to be in the future. As cPACs can exert stereospecific toxicity in the aquatic environment, it is essential to better understand their stereoselective behaviour here. Therefore, this study aims to provide a new perspective towards comprehensive evaluation of cPACs at a river catchment level, including their stereochemistry as a chemical phenomenon driving fate of chiral molecules in the environment. A large spatial and temporal monitoring program was performed in Southwest England. It included 5 sewage treatment works and the receiving waters of the largest river catchment in Southwest England. Simultaneously, lab-scale microcosm studies in simulated activated sludge bioreactors and river water microcosm were performed to evaluate stereoselective degradation of cPACs. A multi-residue enantioselective method allowed the analysis of a total of 18 pairs of enantiomers and 3 single enantiomers in wastewater and river water samples. Our monitoring program revealed: (1) spatial and temporal variations of cPACs in influent wastewaters resulting from different patterns of usage as well as an (2) enantiomeric enrichment of cPACs, likely due to human metabolism, despite their commercialization as racemic mixtures. A similar chiral signature was observed in effluent and receiving waters. Stereoselective degradation was observed in trickling filters (TF) for naproxen, ketoprofen, cetirizine and 10,11-dihydroxy-10-hydroxycarbamazepine, in sequencing batch reactors (SBR) for ifosfamide and in activated sludge (AS) for cetirizine. The extent of enantiomer-specific fate was wastewater treatment dependent in the case of naproxen (TF showed higher stereoselectivity than AS and SBR) and cetirizine (TF and AS showed higher stereoselectivity than SBR) due to differing microbial population. Furthermore, stereoselective degradation of naproxen was highly variable among STWs using similar treatments (TF) and operating in the same region. Microbial stereoselective degradation was also confirmed by both activated and river water simulated microcosm for chloramphenicol, ketoprofen, indoprofen, naproxen and 10,11-dihydroxy-10-hydroxycarbamazepine. Results from our large scale river catchment monitoring study and lab simulated microcosm show wide-ranging implications of enantiomerism of cPACs on environmental risk assessment (ERA). As two enantiomers of the same compound show different biological effects (e.g. toxicity), their non-racemic presence in the environment might lead to inaccurate ERA. This is because current ERA approaches do not require analysis at enantiomeric level.

Multi-residue analysis of chiral and achiral trace organic contaminants in soil by accelerated solvent extraction and enantioselective liquid chromatography tandem-mass spectrometry.

Reported here is the first analytical methodology for the enantiomeric determination of chiral trace organic contaminants (TOrCs) in soil. Direct enantioselective separations were achieved on a Chirobiotic V2® column operated in polar ionic mode. Initial screening of vancomycin stationary phases found Chirobiotic V2® better suited for multi-residue separation of chiral TOrCs than Chirobiotic V® due to differences in the ligand linkage chemistry. Simultaneous enantioseparation of beta-blockers, beta-agonists, anti-depressants, anti-histamines and stimulants was achieved for the first time. This included the first separation of chlorpheniramine enantiomers with a method suitable for environmental analysis (i.e., coupled to MS). Investigation of mobile phase composition found the concentration of liophilic ions had the greatest influence on enantioseparations and of most importance during method development. The optimized method achieved simultaneous separation of salbutamol, propranolol, atenolol, amphetamine, chlorpheniramine and fluoxetine enantiomers with satisfactory resolution (>1.0). For completeness, such methods also need to support analysis of achiral TOrCs. Therefore three achiral TOrCs (carbamazepine, carbamazepine 10,11 epoxide and triclocarban) were included to demonstrate the methods suitability. Method recoveries for all analytes ranged from 76 to 122% with method quantitation limits (MQLs) <1 ng g-1. Application of the method to soil microcosm studies revealed stereoselective degradation of chiral TOrCs for the first time. For example, S(+)-amphetamine degraded at a faster rate than its corresponding enantiomer leading to an enrichment of R(-)-amphetamine. Therefore to better understand the risk posed from TOrCs on the terrestrial environment, chiral species need profiled at the enantiomeric level. This can now be addressed using the proposed methodology whilst simultaneously profiling achiral TOrCs.

Biotic phase micropollutant distribution in horizontal sub-surface flow constructed wetlands.

The distribution of micropollutants in biotic phases of horizontal sub-surface flow (HSSF) constructed wetlands was investigated. 88 diverse micropollutants (personal care products, pharmaceuticals and illicit drugs) were monitored for in full-scale HSSF steel slag and gravel beds to assess their fate and behaviour during tertiary wastewater treatment. Of the studied micropollutants 54 were found in receiving and treated wastewaters. Treatment reduced concentrations of several micropollutants by >50% (removal range -112% to 98%) and resulted in changes to the stereo-isomeric composition of chiral species. For example, stereo-selective changes were observed for 3,4-methylenedioxymethamphetamine (MDMA) and atenolol during HSSF constructed wetland treatment for the first time. Analysis of sludge present within the HSSF beds found 37 micropollutants to be present. However, concentrations for the majority of these micropollutants were not considered high enough to suggest partitioning into sludge was a contributing mechanism of removal. Nevertheless the preservative methylparaben was found at 2772mgbed-1. Its daily removal from wastewater of 3.4mgd-1 indicates partitioning and accumulation in sludge contributes to its removal. Other micropollutants found at high levels in sludge (relative to their overall removals) were the antidepressants sertraline and fluoxetine, and the metabolite desmethylcitalopram. Furthermore, process balances indicated uptake and metabolism by Phragmites australis (Cav.) Trin. ex Steud did not contribute significantly to micropollutant removal. However analysis of plant tissues evidenced uptake, metabolism and accumulation of recalcitrant micropollutants such as ketamine and carbamazepine. It is considered that the rate of uptake was too slow to have a notable impact on removal at the 14h hydraulic retention time. Despite evidence of other removal mechanisms at play (e.g., partitioning into sludge and plant uptake), findings indicate biodegradation is the dominant mechanism of micropollutant removal in HSSF constructed wetlands.