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Bioanalytical tools, namely in vitro bioassays, can be employed in tandem with chemical analyses to assess the efficacy of wastewater treatment and the potential for adverse effects from the discharges of wastewater into receiving waters. In the present study, samples of untreated wastewater (i.e., influent) and treated wastewater (i.e., effluent) were collected from two wastewater treatment plants and a wastewater treatment lagoon to investigate potential differences in treatment performance. In addition, grab samples of surface water were collected downstream of the lagoon discharge to evaluate the water quality in the receiving stream. After solid-phase extraction (SPE) using ion exchange columns for basic/neutral and acidic compounds, respectively, the extracts were analyzed for a suite of 16 indicator compounds. The two SPE extracts were combined for analysis of biological responses in four in vitro cell-based bioassays. The concentrations of several indicator compounds, including the estrogens, 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), were below the limits of detection. However, androstenedione and estrone were detected in several influent samples. The concentrations of these steroid hormones and some of the other indicator compounds declined during treatment, but acesulfame K, carbamazepine, trimethoprim and DEET persisted in the effluent. The MTS-CellTiter 96® AQueous One Solution Cell Proliferation Assay (MTS) indicated that cell viability was not affected by exposure to the extracts. The Qiagen Nuclear Receptors 10-Pathway Reporter Array indicated that several cellular pathways were upregulated, with the greatest upregulation observed with the estrogen receptor (i.e., induction ratios of 12 to 47) and the liver X receptor (i.e., induction ratios of 10 to 45). The ERα CALUX assay indicated that estrogenic activity was lower in effluents compared to influents, but the expected improved removal of estrogenic activity during nitrification was not observed. The results of the Nrf2 Luciferase Luminescence Assay indicated a lower oxidative stress in the effluent samples, except for the lagoon. Overall, the present study further demonstrates that bioassays provide complementary information to chemical analyses and offer a way to assess treatment performance, even when target contaminants are not detected. There are thus advantages to using a combination of chemical analyses and in vitro bioassays to monitor the treatment efficiency of wastewater treatment plants and to predict the potential impacts of wastewater discharges into receiving waters.

Prompted by a recent report that 6PPD-quinone (6PPD-q), a by-product of a common tire manufacturing additive that is present in road runoff, is toxic to coho salmon (Oncorhynchus kisutch), extracts of water samples collected from an urban river were re-analyzed to determine if this compound was present in stormwater-influenced flows. In addition, extracts were analyzed for 1,3-diphenylguanidine (DPG), which is also used in tire manufacturing. Samples were originally collected in the fall of 2019 and winter of 2020 in the Greater Toronto Area of Canada from the Don River, a highly urbanized watershed in close proximity to several major multi-lane highways. These target compounds were analyzed using ultra-high pressure liquid chromatography with high resolution mass spectrometric detection with parallel reaction monitoring. Both 6PPD-q and DPG were detected above limits of quantification (i.e., 0.0098 µg/L) in all extracts. Maximum concentrations for 6PPD-quinone of 2.30 ± 0.05 µg/L observed in the river during storm events exceeded the LC50 for this compound for coho salmon (i.e., > 0.8 µg/L). In composite samples collected at intervals throughout one rain event, both compounds reached peak concentrations a few hours after initiation of the event (i.e., 0.52 µg/L for DPG and 2.85 µg/L for 6PPD-q), but the concentrations of 6PPD-q remained elevated above 2 µg/L for over 10-h in the middle of the event. Estimates of cumulative loads of these compounds in composite samples indicated that kg amounts of these compounds entered the Don River during each hydrological event, and the loads were proportional to the amounts of precipitation. This study contributes to the growing literature indicating that potentially toxic tire-wear compounds are present at elevated levels and are transported via road runoff into urban surface waters during rain events. Supplementary Information The online version contains supplementary material available at 10.1007/s00244-021-00878-4.

Tetracyclines are one of the antibiotics widely employed worldwide and frequently detected in surface waters because of incomplete removal from wastewater treatment. Various advanced oxidation processes have been investigated for tetracyclines degradation and their transformation products (TPs) have recently gained more attention. Studies on ozonation are however seldom for the degradation of oxytetracycline (OTC) and doxycycline (DTC). In the present study, a lower O

It is well established that persistent organic pollutants are transported long distances in the atmosphere and deposited into aquatic and terrestrial ecosystems in remote areas, including high altitude lakes. The objective of this research was to evaluate whether compounds of wastewater origin were present in four remote upland headwater lakes in Ireland that primarily receive loadings from atmospheric deposition. Using Polar Organic Chemical Integrative Samplers (POCIS) deployed in the lakes for 60 to 68 days, seven compounds were detected at levels that could be quantified but 25 of the target compounds were not detected. The detected compounds included the cannabinoid metabolite, tetrahydrocannabinol carboxylate (THC-COOH), codeine, acetaminophen (paracetamol), ibuprofen, and the artificial sweeteners, sucralose, and saccharin, which were all present at concentrations estimated to be 125 ng/L. Caffeine was also present in the lakes at estimated concentrations between 213 and 1320 ng/L. Cocaine and tramadol were detected in POCIS deployed in some of the lakes, but at levels below the limits of quantitation. The highest concentrations of the target analytes were detected in two lakes located in the eastern part of Ireland. These data are consistent with regional atmospheric transport of these compounds originating from wastewater treatment plants in Ireland. However, contaminants from wastewater treatment plants in the United Kingdom may also be a source in these upland lakes that are located far from emissions of urban pollution.

Gestagens are active ingredients in human and veterinary drugs with progestogenic activity. Two gestagens—progesterone (P4), and the synthetic P4 analogue, melengestrol acetate (MGA)—are approved for use in beef cattle agriculture in North America. Both P4 and MGA have been measured in surface water receiving runoff from animal agricultural operations. This project aimed to assess the morphometric and molecular consequences of chronic exposures to P4, MGA, and their mixture during Western clawed frog metamorphosis. Chronic exposure (from embryo to metamorphosis) to MGA (1.7 µg/L) or P4 + MGA (0.22 µg/L P4 + 1.5 µg/L MGA) caused a considerable dysregulation of metamorphic timing, as evidenced by an inhibition of growth, narrower head, and lack of forelimb emergence in all animals. Molecular analysis revealed that chronic exposure to the mixture induced an additive upregulation of neurosteroid-related (GABAA receptor subunit α6 (gabra6) and steroid 5-alpha reductase 1 (srd5α1) gene expression in brain tissue. Chronic P4 exposure (0.26 µg/L P4) induced a significant upregulation of the expression hypothalamic–pituitary–gonadal (HPG)-related genes (ipgr, erα) in the gonadal mesonephros complex (GMC). Our data suggest that exposure to P4, MGA, and their mixture induces multiple endocrine responses and adverse effects in larval Western clawed frogs. This study helps to better our understanding of the consequences of chronic gestagen exposure and suggests that the implications and risk of high gestagen use in beef cattle feeding operations may extend to the aquatic environment.

Consumption of amphetamine and methamphetamine, two common illicit drugs, has been monitored by wastewater-based epidemiology (WBE) in many countries over the past decade. There is potential for the estimated amount of amphetamine used to be skewed at locations where methamphetamine is also consumed, because amphetamine is also excreted to wastewater following methamphetamine consumption. The present study aims to review the available data in the literature to identify an average ratio of amphetamine/methamphetamine (AMP/METH) that is excreted to wastewater after methamphetamine consumption. This ratio could then be used to refine the estimation of amphetamine consumption in catchments where there is both amphetamine and methamphetamine use. Using data from more than 6000 wastewater samples from Australia where methamphetamine is the dominant illicit amphetamine-type substance on the market, we were able to subtract the contribution of legal sources of amphetamine contribution and obtain the median AMP/METH ratio in wastewater of 0.09. Using this value, the amphetamine derived from methamphetamine consumption can be calculated and subtracted from the total amphetamine mass loads in wastewater samples. Without considering the contribution of amphetamine from methamphetamine use, selected European catchments with comparable consumption of amphetamine and methamphetamine showed up to 83% overestimation of amphetamine use. For catchments with AMP/METH ratio greater than 1.00, the impact of amphetamine from methamphetamine would be negligible; for catchments with AMP/METH ratio in the range of 0.04-0.19, it will be difficult to accurately estimate amphetamine consumption.

This research evaluates photocatalytic ozonation for removing 5 PFAS (PFOA/PFHxS/PFBS/6:2 FTS/GenX) from water using a WO

New psychoactive substances (NPS) are compounds designed to mimic both licit and illicit drugs, and these substances are being discovered each year through forensic toxicology, drug enforcement agencies, and health authorities. However, there is limited information surrounding their international popularity. In this work, influent wastewater samples (n = 144) were collected from 25 sites in 10 countries: Australia, Belgium, Canada, China, Fiji, Italy, New Zealand, Republic of Korea, Spain, and the United States over the 2020-2021 New Year period. All samples were extracted in the country of origin then shipped and analyzed centrally at the University of South Australia using validated liquid chromatography-mass spectrometry methods. This study focused on 28 NPS stimulants, with 11 detected. The emerging substances eutylone and 3-methylmethcathinone (3-MMC) were detected most frequently and with the highest mass loads, indicating international popularity. Interestingly, the "older"generation stimulants, para-methoxyamphetamine (PMA), methylone, and mephedrone, were also detected. From the sites monitored in this work, areas in New Zealand had the highest loads of NPS stimulant consumption. Results here show that wastewater analysis can elucidate the dynamic nature of the NPS market, providing near real-time information on changing consumption patterns whose information can be used to minimize public risk. Refereed/Peer-reviewed

Community rescue occurs when ecological or evolutionary processes restore positive growth in a highly stressful environment that was lethal to the community in its ancestral form, thus averting biomass collapse in a deteriorating environment. Laboratory evidence suggests that community rescue is most likely in high-biomass communities that have previously experienced moderate doses of sublethal stress. We assessed this result under more natural conditions, in a mesocosm experiment with phytoplankton communities exposed to the ubiquitous herbicide glyphosate. We tested whether community biomass and prior herbicide exposure would facilitate community rescue after severe contamination. We found that prior exposure to glyphosate was a very strong predictor of the rescue outcome, while high community biomass was not. Furthermore, although glyphosate had negative effects on diversity, it did not influence community composition significantly, suggesting a modest role for genus sorting in this rescue process. Our results expand the scope of community rescue theory to complex ecosystems and confirm that prior stress exposure is a key predictor of rescue.

Endocrine disrupting chemicals (EDCs) are found in every environmental medium and are chemically diverse. Their presence in water resources can negatively impact the health of both human and wildlife. Currently, there are no mandatory screening mandates or regulations for EDC levels in complex water samples globally. Bioassays, which allow quantifying in vivo or in vitro biological effects of chemicals are used commonly to assess acute toxicity in water. The existing OECD framework to identify single-compound EDCs offers a set of bioassays that are validated for the Estrogen-, Androgen-, and Thyroid hormones, and for Steroidogenesis pathways (EATS). In this review, we discussed bioassays that could be potentially used to screen EDCs in water resources, including in vivo and in vitro bioassays using invertebrates, fish, amphibians, and/or mammalians species. Strengths and weaknesses of samples preparation for complex water samples are discussed. We also review how to calculate the Effect-Based Trigger values, which could serve as thresholds to determine if a given water sample poses a risk based on existing quality standards. This work aims to assist governments and regulatory agencies in developing a testing strategy towards regulation of EDCs in water resources worldwide. The main recommendations include 1) opting for internationally validated cell reporter in vitro bioassays to reduce animal use & cost; 2) testing for cell viability (a critical parameter) when using in vitro bioassays; and 3) evaluating the recovery of the water sample preparation method selected. This review also highlights future research avenues for the EDC screening revolution (e.g., 3D tissue culture, transgenic animals, OMICs, and Adverse Outcome Pathways (AOPs))., This work was supported by the Fonds de recherche du Québec - Nature et technologies (FRQNT-290501) to JR, Natural Sciences and Engineering Research Council (NSERC) of Canada (NSERC-DG-2020-06475), and Canada Research Chairs to VSL (CRC-950-232235). LNM was supported by a H2020-Marie Skłodowska-Curie Action MSCA-IF-RI- 2017 awarded by the European Commission (ref. 797725-EpiSTOX). The authors are grateful to the Intersectorial Centre for Endocrine Disruptor Analysis (ICEDA)'s researcher network that facilitated this Special Issue. We thank Peta Neale that compiled references from the literature for EBT value that can be found in Table 3.

Anthropogenic environmental change is causing habitat deterioration at unprecedented rates in freshwater ecosystems. Despite increasing more rapidly than other agents of global change, synthetic chemical pollution -including agrochemicals such as pesticides- has received relatively little attention in freshwater community and ecosystem ecology. Determining the combined effects of multiple agrochemicals on complex biological properties remains a major challenge, requiring a cross-field integration of ecology and ecotoxicology. Using a large-scale array of experimental ponds, we investigated the response of zooplankton community properties (biomass, composition, and diversity metrics) to the individual and joint presence of three globally widespread agrochemicals: the herbicide glyphosate, the neonicotinoid insecticide imidacloprid, and nutrient fertilizers. We tracked temporal variation in zooplankton biomass and community structure (i.e., composition and diversity) along single and combined pesticide gradients (each spanning eight levels), under low (mesotrophic) and high (eutrophic) nutrient-enriched conditions, and quantified (i) response threshold concentrations, (ii) agrochemical interactions, and (iii) community resistance and recovery. We found that the biomass of major zooplankton groups differed in their sensitivity to pesticides: ≥0.3 mg/L glyphosate elicited long-lasting declines in rotifer communities, both pesticides impaired copepods (≥3 µg/L imidacloprid and ≥5.5 mg/L glyphosate), whereas some cladocerans were highly tolerant to pesticide contamination. Strong interactive effects of pesticides were only recorded in ponds treated with the combination of the highest doses. Overall, glyphosate was the most influential driver of aggregate community properties of zooplankton, with biomass and community structure responding rapidly but recovering unequally over time. Total community biomass showed little resistance when first exposed to glyphosate, but rapidly recovered and even increased with glyphosate concentration over time; in contrast, taxon richness decreased in more contaminated ponds but failed to recover. Our results indicate that the biomass of tolerant taxa compensated for the loss of sensitive species after the first exposure, conferring greater community resistance upon a subsequent contamination event; a case of pollution-induced community tolerance in freshwater animals. These findings suggest that zooplankton biomass may be more resilient to agrochemical pollution than community structure; yet all community properties measured in this study were affected at glyphosate concentrations below common water quality guidelines in North America.

A sensitive method based on ultrasound-assisted liquid extraction coupled with liquid chromatography was applied to screen 18 plastic-related contaminants in 168 food composites (namely fish fillets, chicken breast, canned tuna, leafy vegetables, bread and butter) collected in Montreal (Canada), Pretoria and Vhembe (South Africa). Bisphenol A (BPA), bisphenol S (BPS) and seven plasticizers (di-n-butyl phthalate (DBP), diethyl phthalate (DEP), (2-ethylhexyl) phthalate (DEHP), di-(2-ethylhexyl) adipate (DEHA), di-isononyl phthalate (DINP), di-(isononyl)-cyclohexane-1,2-dicarboxylate (DINCH)) were detected in different foods from both countries. DBP and DEP were the most frequently detected contaminants in food collected in Montreal (75% for both) and DINP was the most frequently detected contaminant in food from South Africa (67%). DEHA concentration in packaged fish were significantly higher than the values for non-packaged fish (p 0.01) suggesting that the packaging film can be one source of DEHA in fish.

Agricultural pollution with fertilizers and pesticides is a common disturbance to freshwater biodiversity. Bacterioplankton communities are at the base of aquatic food webs, but their responses to these potentially interacting stressors are rarely explored. To test the extent of resistance and resilience in bacterioplankton communities faced with agricultural stressors, we exposed freshwater mesocosms to single and combined gradients of two commonly used pesticides: the herbicide glyphosate (0-15 mg/L) and the neonicotinoid insecticide imidacloprid (0-60 μg/L), in high or low nutrient backgrounds. Over the 43-day experiment, we tracked variation in bacterial density with flow cytometry, carbon substrate use with Biolog EcoPlates, and taxonomic diversity and composition with environmental 16S rRNA gene amplicon sequencing. We show that only glyphosate (at the highest dose, 15 mg/L), but not imidacloprid, nutrients, or their interactions measurably changed community structure, favoring members of the Proteobacteria including the genus Agrobacterium. However, no change in carbon substrate use was detected throughout, suggesting functional redundancy despite taxonomic changes. We further show that communities are resilient at broad, but not fine taxonomic levels: 24 days after glyphosate application the precise amplicon sequence variants do not return, and tend to be replaced by phylogenetically close taxa. We conclude that high doses of glyphosate – but still within commonly acceptable regulatory guidelines – alter freshwater bacterioplankton by favoring a subset of higher taxonomic units (i.e. genus to phylum) that transiently thrive in the presence of glyphosate. Longer-term impacts of glyphosate at finer taxonomic resolution merit further investigation.

Bioanalytical tools, namely in vitro bioassays, can be employed in tandem with chemical analyses to assess the efficacy of wastewater treatment and the potential for adverse effects from the discharges of wastewater into receiving waters. In the present study, samples of untreated wastewater (i.e. influent) and treated wastewater (i.e. effluent) were collected from two wastewater treatment plants and a wastewater treatment lagoon serving municipalities in southern Ontario, Canada. In addition, grab samples of surface water were collected downstream of the lagoon discharge. After solid phase extraction (SPE) using ion-exchange columns for basic/neutral and acidic compounds, respectively, the extracts were analyzed for a suite of 16 indicator compounds. The two SPE extracts were combined for analysis of biological responses in four in vitro cell-based bioassays. The concentrations of several indicator compounds, including the estrogens, 17β-estradiol and 17α-ethinylestradiol, were below the limits of detection. However, androstenedione and estrone were detected in several influent samples. The concentrations of these steroid hormones and some of the other indicator compounds declined during treatment but acesulfame K, carbamazepine, trimethoprim and DEET persisted in the effluent. The MTS- CellTiter 96® AQueous One Solution Cell Proliferation Assay (MTS) indicated that cell viability was not affected by exposure to the extracts. The Qiagen Nuclear Receptors 10-Pathway Reporter Array indicated that several cellular pathways were upregulated, with the greatest upregulation observed with the estrogen receptor (i.e. induction ratios 12 to 47) and the liver X receptor (i.e. induction ratios 10 to 45). The ERα CALUX assay indicated that estrogenic activity was lower in effluents compared to influents, with the greatest estrogenic activity observed for grab samples of influent from the lagoon (i.e. 56-215 ng L-1 17β-estradiol equivalents). Finally, the results of the Nrf2 Luciferase Luminescence Assay indicated a lower oxidative stress in the effluent samples. Overall, the present study demonstrates that chemical analyses are limited in their ability to predict or explain reductions in the toxicity of treated wastewater. There are thus advantages to using a combination of chemical analyses and in vitro bioassays to monitor the treatment efficiency of wastewater treatment plants and to predict the potential impacts of wastewater discharges into receiving waters.

Pharmaceuticals and personal care products, antibiotics, estrogens, and antiandrogens are found widely in aquatic environments. Monitoring studies by sampling surface water and effluents of wastewater treatment plants (WWTPs) have been conducted recently to monitor antiandrogens, which, along with estrogens, cause endocrine disruption. However, few studies have investigated antiandrogenic activity (AA) combined with a chemical analyses of emerging antiandrogens. Therefore, we analyzed the presence and persistence of 12 types of antiandrogens, atrazine, and carbamazepine using grab sampling and polar organic chemical integrative sampler (POCIS) along a river affected by WWTP discharges. Water and sediment samples were collected from the WWTP effluent (WW), as well as upstream (US) and downstream (DS) of the WWTP. We detected only tebuconazole, triclosan, propiconazole, and fluconazole during the two sampling campaigns in 2016 and 2017. Grab sampling of the site WW detected tebuconazole (7–77 ng/L), propiconazole (5–47 ng/L), and fluconazole (6–45 ng/L). However, the concentrations in the river water were below the detection limits. Nevertheless, fluconazole and triclosan were detected by POCIS in the site WW (45.7 and 26.8 ng/L, respectively) and all river samples ranges of 0.3–9.3 and 2.4–3.7, respectively. This detection was attributed to the limit of quantification of POCIS being lower than that of grab sampling. Nilutamide and triclosan were detected in the river sediment, suggesting that their concentrations in the water column were at least partly attenuated through sediment sorption. We also observed AA by analyzing POCIS extracts with the yeast androgen screen assay. The highest AA was found in the site WW and it was still observable several kilometers downstream of the point of discharge despite decreasing. Therefore, the WWTP effluent was most likely contributor to the persistent AA in the river.

Wastewater-based epidemiology is an additional indicator of drug use that is gaining reliability to complement the current established panel of indicators. The aims of this study were to: (i) assess spatial and temporal trends of population-normalized mass loads of benzoylecgonine, amphetamine, methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) in raw wastewater over 7 years (2011-17); (ii) address overall drug use by estimating the average number of combined doses consumed per day in each city; and (iii) compare these with existing prevalence and seizure data.Analysis of daily raw wastewater composite samples collected over 1 week per year from 2011 to 2017.Catchment areas of 143 wastewater treatment plants in 120 cities in 37 countries.Parent substances (amphetamine, methamphetamine and MDMA) and the metabolites of cocaine (benzoylecgonine) and of ΔBenzoylecgonine was the stimulant metabolite detected at higher loads in southern and western Europe, and amphetamine, MDMA and methamphetamine in East and North-Central Europe. In other continents, methamphetamine showed the highest levels in the United States and Australia and benzoylecgonine in South America. During the reporting period, benzoylecgonine loads increased in general across Europe, amphetamine and methamphetamine levels fluctuated and MDMA underwent an intermittent upsurge.The analysis of wastewater to quantify drug loads provides near real-time drug use estimates that globally correspond to prevalence and seizure data.

Calcium-silicate mineral Polonite® and aluminum-based catalyst (AL-1010S), previously identified as promising materials for catalytic ozonation, were used as catalysts to investigate the impact of some operating conditions (ratio ozone feed concentration to catalyst load) and wastewater characteristics (chemical oxygen demand - COD and nitrite - NO2 concentration) on the disinfection and removal of contaminants of emerging concern (CECs) during catalytic ozonation of wastewater. Tests conducted in synthetic wastewater using two different ozone gas concentration (4 and 8 g (nm3)) and 6 different catalyst loads provided ratios of 0.08, 0.11, 0.16, and 0.32. Results from the experiments indicated that the ratio of 0.11 was optimal and reached residual disinfection below 2 MPN mL−1 from the initial concentration of 5 ± 2 × 105 MPN mL−1 and removal of atrazine (ATZ) above 80% from the initial concentration of 100 ± 10 μg L−1 for an ozone dose of 41–45 mg L−1. Catalytic ozonation with the selected materials enhanced disinfection and ATZ removal from synthetic wastewater (SWW) in comparison to non-catalytic ozonation by making the treatment performance less sensitive to increased chemical oxygen demand (COD) and nitrite (NO2) in the matrix. Validation of the results in real wastewater effluents confirmed that catalytic ozonation enhanced disinfection. Catalytic ozonation using Polonite® and AL-1010S provided residual bacteria level of 0.6 ± 0.42 MPN mL−1 and 0.29 ± 0.41 MPN mL−1, while non-catalytic ozonation lead to an average residual bacteria level of 1.26 ± 0.09 MPN mL−1 for the same range of transferred ozone dose. However, under the conditions tested, a limited number of CECs were extracted at levels above the limits of quantification and further validation work required to evaluate the performance of catalytic ozonation for the removal of CECs.

The purpose of this work was to identify novel materials that could be used for the catalytic ozonation of wastewater for improved removal of micropollutants and disinfection. The materials chosen for investigation were selected based on their commercial availability and composition characteristics that suggested that they could act as catalysts. Synthetic wastewater (SWW) was used to mimic municipal secondary effluent wastewater while obtaining constant and reproducible matrix characteristics. Polonite®, wollastonite, zeolite, TiO2-Al2O3 (8%/92%), and AL-1010S (AlO2-based) were tested for their potential impact on efficiency of disinfection, based on the removal of E. coli bacteria and removal of contaminants of emerging concern (CECs), relative to conventional ozonation. Atrazine (ATZ), ibuprofen (IBP), naproxen (NPX), and gemfibrozil (GBZ) were used as indicator compounds. Zeolite and wollastonite did not promote disinfection and CECs removal; TiO2-Al2O3 and AL-1010S provided improvement for both criteria, but to a lesser extent in SWW than in Milli-Q water; and Polonite® did not enhance the removal of CECs but led to the higher E. coli inactivation. These results suggest that Polonite®, AL-1010S, and TiO2-Al2O3 can act as catalysts and provide mechanisms to lower the ozone dose required to reach disinfection. The apparent kinetic constant of the reaction for the catalytic ozonation of ATZ, in the ultrapure water, was determined for Polonite®, TiO2-Al2O3 and AL-1010S. The reusability of the catalysts was demonstrated over four consecutive cycles of 6 h of treatment in a continuous flow ozonation system.

Removal of pharmaceuticals from wastewater using chemical processes is a promising solution to mitigate pollution in drinking and surface waters. Non-catalytic wet air oxidation (WAO) is a highly efficient advanced oxidation process that uses air and water at high temperatures and pressures to remove high concentrations of organic compounds from various wastes without use of catalysts. However, the elimination of pharmaceuticals in hospital wastewater with a low organic content by WAO has not yet been sufficiently studied. The objective of the present study was to evaluate both the efficiency and costs of WAO treatment to remove pharmaceuticals present in hospital effluents. First, a laboratory-scale WAO batch unit was used to optimize oxidation temperatures and residence times to achieve high elimination of ten pharmaceuticals of interest in spiked deionized water. Then, optimal conditions were applied to treat hospital wastewater effluents. Results showed that even at low chemical oxygen demand values (

Background Monitoring drug use in Mexico is a challenge due to emerging drugs and rapid changes in consumption patterns. The temporal and geographical patterns of cocaine, methamphetamine, amphetamine, MDMA, cannabis, heroin, ketamine, and fentanyl were examined in Mexican cities using wastewater-based epidemiology (WBE). Methods 105 daily composite wastewater samples were collected from sewage treatment plants in fifteen Mexican cities. We quantified drug residues using liquid chromatography–high-resolution mass spectrometry, and estimated drug use by back-calculation of drug loads. Results We identified ten drug target residues in at least one sample across cities. Drugs with the highest median levels were cannabis, methamphetamine, and cocaine. The median range of cannabis for one week was between 147 and 20,364 mg/day/1000inhab across cities, whereas methamphetamine ranged between 5 and 3,628 mg/day/1000inhab. Cocaine was found in levels between 2 and 370 mg/day/1000inhab. The highest levels of methamphetamine and amphetamine were observed in the US border cities of Tijuana and San Luis Rio Colorado. The presence of heroin, MDMA, ketamine, and fentanyl was stronger during weekends, while cannabis, cocaine, and amphetamine were found throughout the week. Conclusion This study provides the first report of fentanyl, norfentanyl, and ketamine in wastewater in Mexico. The results indicate an increased presence of drugs on known drug traffic routes, demonstrating that WBE can help identify areas of high drug use and assist governments in developing policies to reduce drug use and harm in the communities.

Two separate pilot-scale studies were performed at two wastewater treatment plants comparing conventional ozonation and catalytic ozonation with an alumina-based catalyst supplied by BASF. The results of the first pilot study showed that catalytic ozonation achieved the same degree of disinfection as conventional ozonation with 30% lower applied ozone dose and enhanced the removal of several contaminants of emerging concern (CECs). The second pilot study conducted over 6 months of operation with the same batch of catalyst showed sustained enhanced removal of CECs relative to ozonation alone. The removals of CECs by catalytic ozonation was particularly effective for compounds with low reaction rates with ozone, indicating reactions with hydroxyl radicals formed in the presence of the catalyst. Analysis of plasma vitellogenin and total glutathione in liver tissues of juvenile rainbow trout (Oncorhynchus mykiss) injected with wastewater extracts indicated that catalytic ozonation removed the estrogenic activity and modulated oxidative stress caused by exposure to the organic compounds in wastewater extracts. Analysis of other biomarker responses indicated that no transformation products were formed that can cause lipid damage in the liver or affect levels of a brain neurotransmitter (i.e. serotonin). Catalytic ozonation is a promising technology to increase the efficiency of ozone treatment of municipal wastewater and to meet increasingly more stringent regulations for effluent quality.

Real-time, high resolution, simultaneous measurement of multiple ionic species is challenging with existing chromatographic, spectrophotometric and potentiometric techniques. Potentiometric ion sensors exhibit limitations in both resolution and selectivity. Herein, we develop wafer scale graphene transistor technology for overcoming these limitations. Large area graphene is an ideal material for high resolution ion sensitive field effect transistors (ISFETs), while simultaneously enabling facile fabrication as compared to conventional semiconductors. We develop the ISFETs into an array and apply Nikolskii–Eisenman analysis to account for cross-sensitivity and thereby achieve high selectivity. We experimentally demonstrate real-time, simultaneous concentration measurement of K+, Na+, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm{NH}}}_{4}^{+}$$\end{document}NH4+, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm{NO}}}_{3}^{-}$$\end{document}NO3−, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm{SO}}}_{4}^{2-}$$\end{document}SO42−, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm{HPO}}}_{4}^{2-}$$\end{document}HPO42− and Cl− with a resolution of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim\! 2\times 1{0}^{-3}\,{\mathrm{log}}\,$$\end{document}~2×10−3log concentration units. The array achieves an accuracy of ±0.05 log concentration. Finally, we demonstrate real-time ion concentration measurement in an aquarium with lemnoideae lemna over three weeks, where mineral uptake by aquatic organisms can be observed during their growth., The authors demonstrate wafer-scale, graphene-based ion sensitive field effect transistors arrays for simultaneous concentration measurement of K+, Na+, NH4+, NO3−, SO42−, HPO42− and Cl−, and use their technology for real-time ion concentration measurements in an aquarium with lemnoideae lemna over a period of three weeks.

Background and aims Wastewater‐based epidemiology is an additional indicator of drug use that is gaining reliability to complement the current established panel of indicators. The aims of this study were to: (i) assess spatial and temporal trends of population‐normalized mass loads of benzoylecgonine, amphetamine, methamphetamine and 3,4‐methylenedioxymethamphetamine (MDMA) in raw wastewater over 7 years (2011–17); (ii) address overall drug use by estimating the average number of combined doses consumed per day in each city; and (iii) compare these with existing prevalence and seizure data. Design Analysis of daily raw wastewater composite samples collected over 1 week per year from 2011 to 2017. Setting and Participants Catchment areas of 143 wastewater treatment plants in 120 cities in 37 countries. Measurements Parent substances (amphetamine, methamphetamine and MDMA) and the metabolites of cocaine (benzoylecgonine) and of Δ9‐tetrahydrocannabinol (11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol) were measured in wastewater using liquid chromatography–tandem mass spectrometry. Daily mass loads (mg/day) were normalized to catchment population (mg/1000 people/day) and converted to the number of combined doses consumed per day. Spatial differences were assessed world‐wide, and temporal trends were discerned at European level by comparing 2011–13 drug loads versus 2014–17 loads. Findings Benzoylecgonine was the stimulant metabolite detected at higher loads in southern and western Europe, and amphetamine, MDMA and methamphetamine in East and North–Central Europe. In other continents, methamphetamine showed the highest levels in the United States and Australia and benzoylecgonine in South America. During the reporting period, benzoylecgonine loads increased in general across Europe, amphetamine and methamphetamine levels fluctuated and MDMA underwent an intermittent upsurge. Conclusions The analysis of wastewater to quantify drug loads provides near real‐time drug use estimates that globally correspond to prevalence and seizure data., This study was supported by the following countries, institutions and projects Australia: Thyne Reid foundation; Canada: Natural Sciences and Engineering Research Council of Canada (NSERC); Iceland: The Icelandic Research Fund (Grant number 163049–051); Slovenia: Slovene Research Agency (funding Project L1–9191); Spain: MINECO/AEI projects (CTM2014–56628‐C3–2‐R, CTQ2015–65603‐P, CTM2016–81935‐REDT, CTM2017–84763‐C3–2‐R), Galician Council of Culture, Education and Universities (ED481D 2017/003); UK: Environmental Sustainability Knowledge Transfer Network, Engineering and Physical Sciences Research Council and Thermo Fisher Scientific (CASE industrial scholarship for K. Munro, Ref.: EP/J502029/1). European Monitoring Centre for Drugs and Drug Addiction (EMCDDA); EU International Training Network SEWPROF (Marie Curie‐FP7‐PEOPLE, grant number 317205); COST Action ES1307 supported by COST (European Cooperation in Science and Technology); WATCH (Wastewater Analysis of Traces of illicit drug‐related Chemicals for law enforcement and public Health DG migration and Home affairs ‐ HOME/2015/ISFP/PR/DRUG/0062). Sampling support and provision of catchment information Austria: Klemens Geiger and Michael Schlapp; Belgium: Jonathan Phariseau, Bart Coene, Luc Van Os, Peter Nys, Dieter Lemaire, Jean‐François Mougel, Patrick Vantroyen and Karel Claes; Croatia: Marin Ganjto; Czech Republic: Jiri Stara and Robert Hrich Brněnské; France: Véronique Bremont; Italy: Roberto Mazzini and Francesca Pizza (Milan), Francesco Avolio (Bologna), Fabrizio Moratto and Sergio Ghezzi (Gorizia), Rosanna Brienza and Simona Panariello (Potenza), Pier Paolo Abis and Antonia Attanasio (Bari), Antonella Cicala (Palermo); Norway: Pia Ryrfors; Portugal: João Goulão, José Martins, Pedro Alvaro and Fátima Paixão; Slovakia: Silvia Antalová and Jozef Tichy; Spain: Begoña Martínez López, Cristian Mesa, Santiago Querol Rodriguez, Fernando Llavador, Enrique Albors and Gloria Fayos; the Netherlands: Alex Veltman, Peter Theijssen, Peter van Dijk, Stefan Wijers, Mark Stevens, Ferry de Wilde. Analytical support Australia: Maulik Ghetia; Cyprus: Popi Karaolia; Greece: Nikoilaos Raikos; Spain: Ana Maria Botero‐Coy, Clara Boix, Alberto Celma, Jorge Pitarch, Inés Racamonde and Eddie Fonseca; Italy: Emma Gracia‐Lor, Nikolaos I. Rousis and Noelia Salgueiro‐Gonzalez. Data repository and data screening Eawag: Harald von Waldow; EMCDDA: Renate Hochwieser, Liesbeth Vandam, João Matias and Federica Mathis.

Cannabis is the most commonly used illicit drug worldwide. Its use is becoming less stigmatized as illustrated by the increasing public opinion towards legalization in many countries. Accurate and reliable data on cannabis consumption is, however, needed to assess the impact of new policies and plan prevention strategies carefully. To this aim, measuring drug residues in wastewater, which represent anonymous urine samples of entire populations, can provide valuable information on patterns and trends of drug use, complementing traditional data. This trans-disciplinary approach, known as wastewater-based epidemiology, has demonstrated its value and is well established for monitoring illicit drugs, such as cocaine and amphetamine-type stimulants. However, measuring the main human urinary metabolites of cannabis in wastewater has presented additional challenges and uncertainties related to the analytical measurements, stability and poorly understood excretion rates. Consequently, results often suggested an overestimation of consumption. This chapter aims to identify key aspects, which demand attention and demonstrate the current utility and potential of wastewater analysis for the estimation of cannabis consumption.

Municipal wastewater treatment plants (WWTP) effluents are primary sources of pathogenic microorganisms and contaminants of emerging concern (CECs) released into the aquatic environment. Main concerns regarding these pollutants include transmission of waterborne diseases to humans and toxic and endocrine disrupting effects on aquatic organisms. In the coming years, WWTPs are expected to invest billions of dollars in upgrades to meet new regulatory requirements for wastewater from Environment Canada. For this reason, we investigated the performance of ozone when the technology is used for disinfection to overcome multiple risk factors such as disinfection, CEC removal, endocrine activity and toxicity for real effluents collected from three WWTPs. Two secondary effluents required mean specific ozone doses for disinfection of 0.25 and 1.04 gO3/gDOC whereas the advanced primary effluent required 1.52 gO3/gDOC to achieve a total coliform target disinfection criteria of 1000 MPN/100 ml (equivalent to 200 MPN/100 ml E. coli). At ozone doses for disinfection, CECs with high reactivity with ozone were removed at levels greater than the target CEC removal of 80% for all WWTP effluents. For the secondary effluents, ozone doses above 2.6 ± 0.6 gO3/gDOC were required to satisfy the target removal for the recalcitrant CECs. Within the disinfection ozone dose range, estrogenic activity was reduced by more than 98% and androgenic activity was removed by more than 68%, while the anti-estrogenic activity remained unchanged. Lastly, based on the luminescence inhibition of V. fischeri, ozone doses for disinfection produced secondary effluents exhibiting less than 20% inhibition, thus falling under the hazard classification “no acute/chronic toxicity”.

This paper offers a landscape analysis of communication instruction within six Canadian and two American Engineering faculties by bringing together approaches and perspectives from communication instructors at these institutes. Each instructor shares a summary of their institution’s approach to communication instruction, before discussing a course-level initiative. Similarities between these approaches at a course and institutional level are summarized and discussed.

Microcystin-LR (MC-LR) is the most common cyanotoxin released from algal-blooms. The study investigated the MC-LR adsorption mechanisms by comparing adsorption performance of protonated mesoporous carbon/silica (MC-H, MS-H) and their amino-functionalized forms (MC-NH2 and MS-NH2) considering surface chemistry and pore characteristics. The maximum MC-LR adsorption capacity (Langmuir model) of MC-H (37.87 mg/g) was the highest followed by MC-NH2 (29.25 mg/g) and MS-NH2 (23.03 mg/g), because pore structure is partly damaged during amino-functionalization. However, MC-NH2 (k2 = 0.042 g/mg/min) reacted faster with MC-LR than MC-H during early-stage adsorption due to enhancing electrostatic interactions. Intra-particle diffusion model fit indicated Kp,1 of MC-H (2.11 mg/g/min1/2) was greater than MC-NH2 due to its greater surface area and pore volume. Also, large mesopore diameters are favorable to MC-LR adsorption by pore diffusion. The effect of adsorbate molecular size on adsorption trend against MC-H, MC-NH2 and MS-NH2 was determined by kinetic experiments using two dyes, reactive blue and acid orange: MS-NH2 achieved the highest adsorption for both dyes due to the large number of amino groups on its surface (41.2 NH2/nm2). Overall, it was demonstrated that adsorption of MC-LR on mesoporous materials is governed by (meso-)pore diffusion and π – π (and hydrophobic) interactions induced by carbon materials; in addition, positively-charged grafted amino groups enhance initial MC-LR adsorption rate.

Advanced oxidation processes have gained significant attention for treating tetracycline (TC) and oxytetracycline (OTC), however, their oxidation using the photo-Fenton process has not been sufficiently studied. Although degradations of TC and OTC were enhanced by increasing H2O2 and Fe2+ within the ranges investigated (H2O2 = 20–50 mg/L and Fe = 1–10 mg/L) under UV irradiation, further experiments for the photo-Fenton process were conducted with 20 mg/L of H2O2 and 5 mg/L of Fe2+ to balance efficiency and cost. The photo-Fenton process (UV/H2O2/Fe2+) was shown to be more effective to remove TC and OTC than H2O2, ultraviolet (UV), and UV/H2O2 at the same doses of oxidants. Inorganic anions and cations were shown to inhibit the degradation of TC and OTC during the photo-Fenton process, in the following order: HPO42- > HCO3− ≫ SO42- > Cl− and Cu2+ ≫ Ca2+ > Na+. The TC and OTC degradation are generally improved by increasing pH, which is opposite to the kpCBA,obs values, caused by increasing the deprotonation degree of TC and OTC. Four and nine transformation products of TC and OTC, respectively, were detected over the treatment period. Among the transformation products, m/z 443.14 (C22H22N2O8) formed during TC degradation, and m/z 433.16 (C20H20N2O9) and m/z 415.15 (C20H18N2O8) formed during OTC degradation, were reported for the first time. Vibrio fischeri toxicity assessment indicated that the inhibition ratio was decreased with a decreasing TC concentration, while, OTC transformation lead to higher toxicity. The product (m/z 477.15b) was determined to be the compound causing toxicity during degradation of OTC by using the quantitative structure activity relationship (QSAR). This toxic transformation product caused higher inhibition ratios than its parental compound (OTC), but its further oxidization resulted in decreasing the inhibition ratios.

New treatment technologies and quality monitoring tools are needed for Contaminants of Emerging Concern (CECs) in wastewater. The purpose of this work was to assess the LuminoTox as a monitoring tool for CEC-associated toxicity in municipal wastewater during ozone treatment, and to evaluate the impact of different ozone feed concentrations at equivalent ozone doses for removing toxicity. The LuminoTox was sensitive at monitoring changes in toxicity of atrazine (ATZ) in synthetic wastewater (SWW) and in a 14 CECs mix in secondary effluent (SE) during ozone treatment. In both experiments, a decrease in toxicity was observed with increasing transferred ozone dose, which corresponded to a decrease in CEC concentration. For ATZ in SWW, a 5 ppm ozone feed showed better toxicity removal, up to 25% and 35% inhibition for LuminoTox algae biosensors SAPS I and SAPS II, respectively, for statistically equivalent ozone dose pairs of 43 mg (5 ppm ozone feed) and 36 mg (15 ppm ozone feed). The opposite was true for the 14 CECs in SE; the 15 ppm ozone feed showed better toxicity removal, up to a reduction of 37% and 40% for SAPS I and SAPS II inhibition, respectively, for statistically equivalent ozone dose pairs of 42 mg (5 ppm ozone feed) and 42 mg (15 ppm ozone feed). Different feed applications had an impact on the efficiency of toxicity removal for equivalent ozone doses; this efficiency appears to depend on the type of contaminants and/or wastewater matrix.

This study investigated the presence of a variety of pesticides (herbicides, fungicides, and insecticides) in effluent of three wastewater treatment plants as well as their endocrine activities using yeast-based in vitro assays. Although the presence of these contaminants of emerging concern is frequently reported to be present throughout the environment, their presence in wastewater treatment plants has been seldom studied. Of the 18 compounds investigated in this study, imidacloprid was the only compound not detected in all three WWTPs. Concentrations measured ranged from 3ng/L to 27μg/L for fluconazole. The yeast estrogenic and yeast androgenic screen assays were performed on target compounds in order to investigate their endocrine disruption and potential environmental risks to receiving waters. It was found that of the 14 compounds investigated 12 showed either antiestrogenic or antiandrogenic activity and seven compounds showed pleiotropic effects. In addition to confirming endocrine activities of pesticides using the yeast-based assays this study is one of the first to report activities for novel compounds including three neonicotinoids.

The presence of micropollutants in the environment and their toxic impacts on the aquatic environment have raised concern about their inefficient removal in wastewater treatment plants. In this study, the fate of micropollutants of four different classes was simulated in a conventional activated sludge plant using a bioreactor micropollutant fate model coupled to a settler model. The latter was based on the Bürger-Diehl model extended for the first time to include micropollutant fate processes. Calibration of model parameters was completed by matching modelling results with full-scale measurements (i.e. including aqueous and particulate phase concentrations of micropollutants) obtained from a 4-day sampling campaign. Modelling results showed that further biodegradation takes place in the sludge blanket of the settler for the highly biodegradable caffeine, underlining the need for a reactive settler model. The adopted Monte Carlo based calibration approach also provided an overview of the model's global sensitivity to the parameters. This analysis showed that for each micropollutant and according to the dominant fate process, a different set of one or more parameters had a significant impact on the model fit, justifying the selection of parameter subsets for model calibration. A dynamic local sensitivity analysis was also performed with the calibrated parameters. This analysis supported the conclusions from the global sensitivity and provided guidance for future sampling campaigns. This study expands the understanding of micropollutant fate models when applied to different micropollutants, in terms of global and local sensitivity to model parameters, as well as the identifiability of the parameters.

High-throughput acute and chronic toxicity tests using Vibrio fischeri were used to assess the toxicity of a variety of fungicides, herbicides, and neonicotinoids. The use of time points beyond the traditional 30 min of an acute test highlighted the sensitivity and applicability of the chronic toxicity test and indicated that for some compounds toxicity is underestimated using only the acute test. The comparison of EC50 values obtained from acute and chronic tests provided insight regarding the toxicity mode of action, either being direct or indirect. Using a structure–activity relationship approach similar to the one used in hazard assessments, the relationship between toxicity and key physicochemical properties of pesticides was investigated and trends were identified. This study not only provides new information regarding acute toxicity of some pesticides but also is one of the first studies to investigate the chronic toxicity of pesticides using the test organism V. fischeri. The findings demonstrated that the initial bioluminescence has a large effect on the calculated effective concentrations for target compounds in both acute and chronic tests, providing a way to improve and standardize the test protocol. In addition, the findings emphasize the need for additional investigation regarding the relationship between a toxicant’s physicochemical properties and mode of action in nontarget organisms.

There is an increasing need for tools to monitor toxicity of contaminants of emerging concern (CECs) in wastewater. The purpose of this work was to assess interferences in the presence of total solids (TS) and total suspended solids (TSS) in the LuminoTox at concentrations typical of those found in municipal secondary effluent (SE) and to evaluate a simple sample enrichment method for increased CEC sensitivity. 4 or 10 µg/L atrazine in different TS concentrations and in corresponding filtrates (TSS removed) exhibited equivalent toxicities. Because the only difference between these two fractions is the TSS, this result demonstrates that, generally, this fraction does not induce toxicity nor interfere with the bioassay. At constant medium-low TS, the LuminoTox was able to detect the presence of 4 µg/L of atrazine but could not distinguish the change in atrazine concentration between 4 and 6 µg/L. No inhibition was observed in the presence of a mix of 14 CECs each at 0.23 µg/L. However, upon sample enrichment by lyophilization (50×), an inhibition of 81 ± 3% was observed. The enriched SE alone (not spiked with CECs) led to an inhibition of 49 ± 1%, indicating the detection of the CEC contribution to toxicity after sample preconcentration. The LuminoTox is a promising tool for monitoring SE; however, if the intent is to detect CECs, enrichment method optimization is required.

The continuous release of pharmaceutical compounds in the environment is of concern due to their potential toxicological effects on living organisms, even at low concentrations. The insufficient removal of bioactive contaminants such as pharmaceuticals by conventional wastewater treatment processes has led scientists to investigate and develop efficient technologies such as advanced oxidation processes (AOPs) to address the issue. The objective of the present work was to study the applicability of thermally-prepared Sb-doped Sn 80% -W 20% -oxide thin film coated electrodes for the photoelectrocatalytic degradation of a recalcitrant pharmaceutical compound, carbamazepine (CBZ). The efficiency of photolytic and photocatalytic processes for removal of CBZ were also evaluated for comparison. The formation of transformation products was investigated and the results showed lower levels of transformation products in the water treated by the photoelectrocatalytic method compared to the photolytic and photocatalytic methods, by the end of 60-min treatment. This suggests a potentially lower overall toxicity of the final solution treated by the photoelectrocatalytic method. An estimation of the energy consumption to reach an order of magnitude reduction in the concentration of CBZ for each type of process indicated a lower energy requirement for the photoelectrocatalytic method, with the highest energy efficiency observed at the applied current density of 6 mA/cm 2 .

The widespread deterioration of our water systems requires new wastewater treatment technologies to ensure environmental protection. Conventional wastewater treatments were not designed for, and are therefore ineffective, at removing contaminants of emerging concern (CECs) such as pharmaceuticals, personal care products, pesticides, and industrial chemicals. Furthermore, treatment processes capable of breaking down CECs may produce toxic transformation products more harmful than the parent chemicals. Heterogeneous photocatalytic ozonation provides a promising option with high degradation and mineralization of organic compounds. The aim of the present paper is to review ecotoxicity reduction in water treated by heterogeneous photocatalytic ozonation as a measure of process viability. The discussion investigates changes in toxicity based on a variety of toxicity tests performed to evaluate potential effects on ecosystems, the types of catalysts and radiation sources used, the nature of the target contaminants, and the type of water matrix treated. Acute toxicity testing, TiO2 catalysts, and mercury-vapour lamps including blacklights were dominant in the reviewed studies, investigated in 86%, 84% and 79% of the papers, respectively. Pharmaceuticals were the main group of chemicals treated and the water matrices used were predominantly pure water and secondary effluent. Overall, the findings of these studies provide evidence that photocatalytic ozonation is an efficient process to remove persistent organic compounds while, most of the time, not increasing the toxicity of the effluent (as reported by 86% of the studies). Due to the wide variation in experimental set-ups, no clear correlation between reaction conditions and toxicity was determined, however, V. fischeri acute toxicity assays and chronic/sublethal tests appeared most sensitive to transformation products. Future studies need to a) incorporate multiple toxicity tests to produce a more reliable and inclusive ecotoxicity assessment of treated effluent and b) investigate immobilized catalysts and energy efficient radiation sources (i.e. solar and LEDs) for industrial applications.

Diatrizoate, a recalcitrant iodinated contrast medium, has been detected in wastewaters and water bodies worldwide, with concentrations in hospital wastewaters in the μg/L range. Considering that conventional wastewater treatment technologies and ozonation fail to adequately remove diatrizoate, there is a need for researching alternative treatment technologies. In the present work, aqueous solutions of diatrizoate were treated in a compact (7.5 mL liquid volume) non-thermal plasma–liquid reactor. Oxygen and air plasmas were used for diatrizoate removal, with oxygen plasma performing better. After 20 min of treatment of 200 μg/L diatrizoate in pure water, oxygen led to 90% degradation whereas air achieved only 20% degradation. Two diatrizoate concentrations were studied: 10 mg/L to facilitate the identification of transformation products when using an oxygen plasma and 200 μg/L, a concentration in the range expected in hospital wastewater. For the oxygen plasma treatment, the energy efficiency for removing diatrizoate was 0.140 g/kWh for C0 = 10 mg/L and 0.006 g/kWh for C0 = 200 μg/L. The following transformation products of diatrizoate were identified: m/z 486A, 504A, 504B, 628, 630A, 630B (previously described in literature) and m/z 486B, 550, 555, 565, 578 (novel). Acute toxicity tests on Aliivibrio fischeri revealed no residual toxicity associated to transformation products. Since diatrizoate is a particularly recalcitrant aqueous organic pollutant, its successful removal and the lack of formation of toxic transformation products indicates that the developed plasma-based technology is promising for treating challenging wastewaters, such as hospital wastewaters.

The potential of using thermally prepared Ni0.6Co0.4-oxide for the electrochemical degradation of organic contaminants was investigated using methylene blue (MB) in an aqueous solution, as a model pollutant. The results of UV spectroscopy obtained during galvanostatic electrolyses at the anode indicated the complete removal of the methylene blue dye. The high removal of chemical oxygen demand (COD) and total organic carbon (TOC) suggested a high level of mineralization of its intermediates. It was found that the electrocatalytic performance of the electrode in the anodic degradation of the organic pollutant was significantly enhanced by the presence of chloride ions in the solution. The improvement in the degradation rate of MB was attributed to the in situ electrogeneration of chlorine active species. The results show that Ni0.6Co0.4-oxide anode can be employed as a stable energy-efficient electrocatalyst in the electrochemical purification of wastewater.

Bench-scale reverse osmosis results were compared to pilot-scale results to evaluate the usefulness of bench-scale studies in assessing full-scale membrane performances in the context of reusing wastewater from a novel saline soil remediation technology. Salt rejection and water recovery capacity were accurately estimated by bench-scale tests, with an average water recovery capacity of 56% with an applied pressure of 3100 kPa and a salt rejection of 92% at 2760 kPa. However, fouling, and concentration polarization were found to differ between scales. Concentration polarisation was 41% higher for the pilot-scale tests, which might be explained by differences in membrane configuration; coupon versus spiral-wound.

Chronic toxicity testing using the luminescent bacterium, Vibrio fischeri, has recently been demonstrated to be a suitable bioassay for water quality monitoring. The toxicity evaluation is typically based on determining the EC50 at specific time points which may lead to overlooking the dynamic nature of luminescence response and limits information regarding the possible mechanisms of action of target compounds. This study investigated various approaches (standard, integral, and luminescence rate inhibition) to evaluate the chronic toxicity of three target compounds (atrazine, trimethoprim, and acetamiprid) using a 96-well plate based method. The chronic toxicity assay and the methods used for EC50 calculation provided in this work resulted in a high-throughput method of chronic toxicity testing and indicated lower EC50 than the values provided by the standard short term methods, indicating higher toxicity. This study emphasizes the need for additional chronic toxicity testing to further evaluate the toxicity of compounds or unknown samples.