Analysis of emerging organic contaminants in water, fish and suspended particulate matter (SPM) in the Joint Danube Survey using solid-phase extraction followed by UHPLC-MS-MS and GC-MS analysis

Transport and dispersion of PFOA and PFOS in the Black Sea

A 3-D transport and dispersion model was applied to study the recent past and future dynamics of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) concentrations in the Black Sea for the 2016-2030 period. The modelled surface concentrations show a distinct seasonal behaviour, shaped by winter to spring convective mixing. A significant increasing long-term trend in PFOS concentrations is established, with concentrations in water layers 200 m below the surface increasing at 4-8% per year. Driving mechanisms for PFOA and PFOS transport and accumulation in the subsurface and deeper layers are the cooling of the surface water in winter and the transport of water masses from the North Western Shelf (NWS) of the Black Sea. A simulated 50% phase-out of PFOA and PFOS from 2020 to 2030 shows a 21% reduction in PFOA, while PFOS continues to increase.

Assessment of legacy and emerging PFAS in the Oder River: Occurrence, distribution, and sources

The purpose of the study was to evaluate the occurrence and distribution of emerging contaminants, poly- and perfluoroalkyl substances (PFAS), in the Polish Oder River, aiming to uncover new insights into their environmental impact. The research aimed to identify potential sources of PFAS, assess water quality levels, and verify compliance with European Union environmental quality standards. The concentrations of 25 PFAS (20 legacy and 5 emerging) in 20 samples from intakes upstream and downstream of urban areas were analyzed using novel, developed in these studies, environmental analytical procedures involving solid phase extraction and liquid chromatography-tandem mass spectrometry. The presence of 14 PFAS was confirmed, and the concentration of Σ14PFAS ranged from 7.6 to 68.0 ng/L. The main components were short-chain analogs. PFBA was the most abundant, accounting for about one-third of all PFAS detected. An exception was observed in the waters of the Gliwice Canal, where ADONA represented half of the detected Σ14PFAS. Alternative PFOS replacements were found in all samples. In 11 of 20 water samples, environmental quality standards for PFOS exceeded the limit of 0.65 ng/L. In 5 of 9 cases, the ability of urban areas to increase PFAS levels in the river was determined. 9.5%-54.4% share of alternative PFAS in relation to the sum of the targeted PFAS showing their increasing use as substitutes for phased-out PFOS. Hierarchical cluster analysis was used to identify potential sources of PFAS. Analysis revealed that PFAS in the Oder River most likely originated from domestic and agricultural wastewater, as well as chemical industry discharges. However, the occurrence of PFAS in the Oder River is low and comparable to other recent European studies. These findings provide valuable insights for environmental management to mitigate the risks associated with PFAS pollution in Polish rivers. Moreover, the developed analytical procedure provides a valuable tool that can be successfully applied by other researchers to monitor PFAS in rivers around the world.

Thiol-yne click post-synthesis of phenylboronic acid-functionalized magnetic cyclodextrin microporous organic network for selective and efficient extraction of antiepileptic drugs

Owing to their incomplete digestion in the human body and inadequate removal by sewage treatment plants, antiepileptic drugs (AEDs) accumulate in water bodies, potentially affecting the exposed humans and aquatic organisms. Therefore, sensitive and reliable detection methods must be urgently developed for monitoring trace AEDs in environmental water samples. Herein, a novel phenylboronic acid-functionalized magnetic cyclodextrin microporous organic network (Fe3O4@CD-MON-PBA) was designed and synthesized via the thiol-yne click post-modification strategy for selective and efficient magnetic solid-phase extraction (MSPE) of trace AEDs from complex sample matrices through the specific B-N coordination, π-π, hydrogen bonding, electrostatic, and host-guest interactions. Fe3O4@CD-MON-PBA exhibited a large surface area (118.5 m2 g-1), rapid magnetic responsiveness (38.6 emu g-1, 15 s), good stability and reusability (at least 8 times), and abundant binding sites for AEDs. Under optimal extraction conditions, the proposed Fe3O4@CD-MON-PBA-MSPE-HPLC-UV method exhibited a wide linear range (0.5-1000 μg L-1), low limits of detection (0.1-0.5 μg L-1) and quantitation (0.3-2 μg L-1), good anti-interference ability, and large enrichment factors (92.2-104.3 to 92.3-98.0) for four typical AEDs. This work confirmed the feasibility of the thiol-yne click post-synthesis strategy for constructing novel and efficient multifunctional magnetic CD-MONs for sample pretreatment and elucidated the significance of B-N coordination between PBA and N-containing AEDs.

A review of cumulative toxic effects of environmental endocrine disruptors on the zebrafish immune system: Characterization methods, toxic effects and mechanisms

Environmental endocrine disrupting chemicals (EDCs), are a type of exogenous organic pollutants, are ubiquitous in natural aquatic environments. Currently, in addition to neurological, endocrine, developmental and reproductive toxicity, ecotoxicology studies on immunotoxicity are receiving increasing attention. In this review, the composition of immune system of zebrafish, the common indicators of immunotoxicity, the immunotoxicity of EDCs and their molecular mechanism were summarized. We reviewed the immunotoxicity of EDCs on zebrafish mainly in terms of immune organs, immunocytes, immune molecules and immune functions, meanwhile, the possible molecular mechanisms driving these effects were elucidated in terms of endocrine disruption, dysregulation of signaling pathways, and oxidative damage. Hopefully, this review will provide a reference for further investigation of the immunotoxicity of EDCs.

The effects of plastic additives on swimming activity and startle response in marine amphipod Echinogammarus marinus

Plastic additives are widely used in plastic production and are found in the environment owing to their widespread applications. Among these additives, N-butyl benzenesulfonamide (NBBS) and triphenyl phosphate (TPHP) are under international watchlist for evaluation, with limited studies on amphipods. Di-ethylhexyl phthalate (DEHP) and dibutyl phthalate (DBP) are banned in some countries and categorised as substances of very high concern. This study aimed to investigate the effects of NBBS, TPHP, DEHP and DBP on the swimming activity of a coastal intertidal marine amphipod, Echinogammarus marinus. Furthermore, this study is the first to quantify startle response in E. marinus in response to light stimuli. Amphipods were exposed to 0, 0.5, 5, 50 and 500 μg/l concentrations of all test compounds. Swimming activity and startle responses were assessed by video tracking and analysis using an 8-min alternating dark and light protocol after exposure on days 7 and 14. We observed an overall compound and light effect on the swimming activity of E. marinus. A significant decrease in swimming distance was found in 500 μg/l NBBS and TPHP. We observed that the startle response in E. marinus had a latency period of >2 s and animals were assessed at 1 s and the sum of the first 5 s. There was a clear startle response in E. marinus during dark to light transition, evident with increased swimming distance. NBBS exposure significantly increased startle response at environmental concentrations, while significant effects were only seen in 500 μg/l TPHP at 5 s. We found no significant effects of DEHP and DBP on swimming behaviour at the concentrations assessed. The findings of this study affirm the necessity for a continuous review of plastic additives to combat adverse behavioural effects that may be transferable to the population levels.

Chromatographic Methods for the Determination of Organic Pollution in Urban Water: A Current Mini Review

The number of pollutants and chemicals with the potential to reach the environment is still largely unknown, which poses great challenges for researchers in various fields of science, environmental scientists, and analytical chemists. Chromatographic techniques, both gas chromatography (GC) and liquid chromatography (LC) coupled with different types of detection, are now invaluable tools for the identification of a wide range of chemical compounds and contaminants in water. This review is devoted to chromatographic techniques GC-MS, GC-Orbitrap-MS, GC-MS/MS, GC-HRMS, GC × GC-TOFMS, GC-ECD, LC-MS/MS, HPLC-UV, HPLC-PDA, UPLC-QTOFMS, used to determinate emerging organic contaminants in aquatic media, mainly in urban water, published in the scientific literature over the past several years. The article also focuses on sample preparation methods used in the analysis of aqueous samples. Most research focuses on minimizing the number of sample preparation steps, reducing the amount of solvents used, the speed of analysis, and the ability to apply it to a wide range of analytes in a sample. This is extremely important in the application of sensitive and selective methods to monitor the status of urban water quality and assess its impact on human health.

Current state of knowledge of environmental occurrence, toxic effects, and advanced treatment of PFOS and PFOA

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic synthetic compounds, with high chemical and thermal stability and a persistent, stable and bioaccumulative nature that renders them a potential hazard for the environment, its organisms, and humans alike. Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) are the most well-known substances of this category and even though they are phased out from production they are still highly detectable in several environmental matrices. As a result, they have been spread globally in water sources, soil and biota exerting toxic and detrimental effects. Therefore, up and coming technologies, namely advanced oxidation processes (AOPs) and advanced reduction processes (ARPs) are being tested for their implementation in the degradation of these pollutants. Thus, the present review compiles the current knowledge on the occurrence of PFOS and PFOA in the environment, the various toxic effects they have induced in different organisms as well as the ability of AOPs and ARPs to diminish and/or eliminate them from the environment.

Tracking down pharmaceutical pollution in surface waters of the St. Lawrence River and its major tributaries

A reconnaissance survey was undertaken to evaluate the occurrence and risks of 27 pharmaceuticals and metabolites in the St. Lawrence watershed. Surface water samples were collected over a five-year period (2017-2021) along a 700-km reach of the St. Lawrence River as well as 55 tributary rivers (overall N = 406 samples). Additionally, depth water samples and sediments were collected near a major wastewater effluent. Caffeine, diclofenac, and venlafaxine were the most recurrent substances (detection rates >80 %), and extremely high levels were found near a municipal effluent (e.g., ibuprofen (860 ng/L), hydroxyibuprofen (1800 ng/L) and caffeine (7200 ng/L)). Geographical mapping and statistical analyses indicated that the St. Lawrence River water mass after the Montreal City effluent was significantly more contaminated than the other water masses, and that contamination could extend up to 70 km further downstream. This phenomenon was repeatedly observed over the five years of sampling, confirming that this is not a random trend. A slight increase in contamination was also observed near Quebec City, but concentrations rapidly declined in the estuarine transition zone. Tributaries with the highest pharmaceutical levels (ΣPharmas ∼400-900 ng/L) included the Mascouche, Saint-Régis, and Bertrand rivers, all located in the densely populated Greater Montreal area. When flowrate was factored in, the top five tributaries in terms of mass load (ΣPharmas ∼200-2000 kg/year) were the Des Prairies, Saint-François, Richelieu, Ottawa, and Yamaska rivers. All samples met the Canadian Water Quality Guideline for carbamazepine. Despite the large dilution effect of the St. Lawrence River, a risk quotient approach based on freshwater PNEC values suggested that four compounds (caffeine, carbamazepine, diclofenac, and ibuprofen) could present intermediate to high risks for aquatic organisms in terms of chronic exposure.

Advances in identifying and managing emerging contaminants in aquatic ecosystems: Analytical approaches, toxicity assessment, transformation pathways, environmental fate, and remediation strategies

Emerging contaminants (ECs) are increasingly recognized as threats to human health and ecosystems. This review evaluates advanced analytical methods, particularly mass spectrometry, for detecting ECs and understanding their toxicity, transformation pathways, and environmental distribution. Our findings underscore the reliability of current techniques and the potential of upcoming methods. The adverse effects of ECs on aquatic life necessitate both in vitro and in vivo toxicity assessments. Evaluating the distribution and degradation of ECs reveals that they undergo physical, chemical, and biological transformations. Remediation strategies such as advanced oxidation, adsorption, and membrane bioreactors effectively treat EC-contaminated waters, with combinations of these techniques showing the highest efficacy. To minimize the impact of ECs, a proactive approach involving monitoring, regulations, and public education is vital. Future research should prioritize the refining of detection methods and formulation of robust policies for EC management.

An Initial Survey on Occurrence, Fate, and Environmental Risk Assessment of Organophosphate Flame Retardants in Romanian Waterways

Organophosphate ester flame retardants (OPFRs) are ubiquitous organic pollutants in the environment and present an important preoccupation due to their potential toxicity to humans and biota. They can be found in various sources, including consumer products, building materials, transportation industry, electronic devices, textiles and clothing, and recycling and waste management. This paper presents the first survey of its kind in Romania, investigating the composition, distribution, possible sources, and environmental risks of OPFRs in five wastewater treatment plants (WWTPs) and the rivers receiving their effluents. Samples from WWTPs and surface waters were collected and subjected to extraction processes to determine the OPFRs using liquid chromatography with mass spectrometric detection. All the target OPFRs were found in all the matrices, with the average concentrations ranging from 0.6 to 1422 ng/L in wastewater, 0.88 to 1851 ng/g dry weight (d.w.) in sewage sludge, and 0.73 to 1036 ng/L in surface waters. The dominant compound in all the cases was tri(2-chloroisopropyl) phosphate (TCPP). This study observed that the wastewater treatment process was inefficient, with removal efficiencies below 50% for all five WWTPs. The environmental risk assessment indicated that almost all the targeted OPFRs pose a low risk, while TDCPP, TCPP, and TMPP could pose a moderate risk to certain aquatic species. These findings provide valuable information for international pollution research and enable the development of pollution control strategies.

Diclofenac eco-geno-toxicity in freshwater algae, rotifers and crustaceans

This study assessed the eco-genotoxic impact of diclofenac (DCF) in sentinel species of the freshwater ecosystem. DCF residues are found in freshwater from few ng/L to tens of μg/L due to the inability of conventional wastewater treatment plants to ensure removal efficiency of the drug. An ample body of literature reports on the acute toxicity of DCF in non-target organisms without addressing potential chronic long-term effects on organisms at actual, environmental concentrations. Herein, assessment for acute and chronic toxicity was performed on organisms in vivo exposed to DCF, specifically on the green alga Raphidocelis subcapitata, the rotifer Brachionus calyciflorus and the crustacean Ceriodaphnia dubia. Furthermore, potential DNA damage and expression of antioxidant genes (MnSOD, Cu/ZnSOD and CAT) were evaluated in crustacean neonates. The toxicological risk of DCF was assessed as well as its. GENOTOXIC RISK: The acute toxicity was observed at concentrations far from those of environmental concern. Rotifers and crustaceans were much more chronically sensitive than the algae to DCF, observing besides, the median effect concentrations at tens of μg/L. In crustaceans, DNA damage was noted at units of μg/L, revealing concentrations of environmental concern. The dysregulated activity of SOD and CAT also showed the ability of DCF to provoke oxidative stress. On assessment of environmental risk, the chronic Risk Quotient (RQ) was above the threshold value of 1. Nevertheless, the genotoxic RQ was significantly greater than the chronic RQ, thus, the need of regulatory bodies to acknowledge the genotoxic impact as an environmental risk factor. To our knowledge, this study is the first investigation to perform environmental genotoxic risk assessment of DCF.

Estimation of per- and poly-fluoroalkyl substances mass loads in the Danube River using passive sampling

As Europe's second longest river, the Danube is an important water source for drinking water and irrigation for many countries, before discharging into the Black Sea in the East. Per- and poly-fluoroalkyl substances (PFAS) have been observed over the last two decades in concentrations exceeding the European Union's drinking water guidelines for total sum of 20 select PFAS of 0.1 μg L-1. Their presence is a result of current and historical use and high environmental persistence, necessitating their monitoring for human risk assessments. The aim of this study is to use recently developed passive sampling technology to calculate time-integrated water concentrations and mass loads of 11 select PFAS at 9 sites along the Danube River. Results indicate ∑11 PFAS concentrations in the range of 9.3-29.6 ng L-1 were not in exceedance of EU drinking water guidelines, but perfluorooctanesulfonic acid (PFOS) was in exceedance of the environmental quality standard (0.65 ng L-1) at all sampling locations. The highest ∑11 PFAS mass loads were observed at Ruse (9.5 kg day-1) and Budapest (6.3 kg day-1), believed to be driven by proximity to industrial facilities and large populations (urban runoff). Finally, we estimate 4.9 kg of total PFAS (∑11 PFAS) were delivered to the Black Sea daily over Summer 2019.

Adsorption of Phenoxyacetic Herbicides from Water on Carbonaceous and Non-Carbonaceous Adsorbents

The increasing consumption of phenoxyacetic acid-derived herbicides is becoming a major public health and environmental concern, posing a serious challenge to existing conventional water treatment systems. Among the various physicochemical and biological purification processes, adsorption is considered one of the most efficient and popular techniques due to its high removal efficiency, ease of operation, and cost effectiveness. This review article provides extensive literature information on the adsorption of phenoxyacetic herbicides by various adsorbents. The purpose of this article is to organize the scattered information on the currently used adsorbents for herbicide removal from the water, such as activated carbons, carbon and silica adsorbents, metal oxides, and numerous natural and industrial waste materials known as low-cost adsorbents. The adsorption capacity of these adsorbents was compared for the two most popular phenoxyacetic herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA). The application of various kinetic models and adsorption isotherms in describing the removal of these herbicides by the adsorbents was also presented and discussed. At the beginning of this review paper, the most important information on phenoxyacetic herbicides has been collected, including their classification, physicochemical properties, and occurrence in the environment.

Selective quantification of diclofenac from groundwater and pharmaceutical samples by magnetic molecularly imprinted polymer-based sorbent coupled with the HPLC-PDA detection

Diclofenac (DCF) is a pharmaceutical contaminant of water bodies and therefore, improvement of analytical techniques for its removal and quantitation is one of the current interests of analysts. Herein, DCF selective magnetic molecularly imprinted polymer (MMIP) has been fabricated and characterized by Fourier transform-infrared spectroscopy, thermogravimetric analysis, vibrating scanning magnetometer, scanning electron microscopy, high-resolution transmission electron microscope, energy-dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller analyzer. Furthermore, the protocol for the quantification of DCF using MMIP-HPLC-PDA combo has been optimized by investigating the effect of the amount of MMIP, type and volume of eluent, and variation of pH. The optimized protocol suggested a method detection limit of 0.042 ng mL^-1 and linearity of results in the range 0.1-100 ng mL^-1 (R² = 0.99). The fabricated material offered recovery of DCF up to 96.38-99.46% from groundwater and pharmaceutical samples with a relative standard deviation of <4%. In addition, the material was found selective and sensitive for DCF among its analogous drugs like mefenamic acid, ketoprofen, fenofibrate, aspirin, ibuprofen, and naproxen.

Novel dual-emission sulfur quantum dot sensing platform for quantitative monitoring of pesticide 2,4-dichlorophenoxyacetic acid

In this work, a novel environment-friendly dual-emission Rhodamine B modified sulfur quantum dots (RhB-SQDs) sensing platform was established to economically monitor organochlorine pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) through regulating the activity of alkaline phosphatase (ALP). This dual emission RhB-SQDs exhibited excellent fluorescence and high photostability with emission wavelengths of 455 nm and 580 nm. ALP catalyzed the hydrolysis of the substrate p-nitrophenyl phosphate to p-nitrophenol, which quenched RhB-SQDs fluorescence at 455 nm due to the internal filtration effect, but had no effect the fluorescence intensity of RhB-SQDs at 580 nm. When 2,4-D was present, the activity of ALP was specifically inhibited and enzymatic reaction was interrupted, leading to the reduction of p-nitrophenol production, so the fluorescence of RhB-SQDs at 455 nm was restored. It demonstrated a good linear relationship between the concentration of 2,4-D and F₄₅₅/F₅₈₀ in the range of 0.050-0.500 μg mL^-1, with a detection limit of 17.3 ng mL^-1. The dual-emission fluorescent probe was successfully realized in the identification of 2,4-D in natural water samples and vegetables with the advantages of exceptional accuracy, immunity to interference, and selectivity. The platform offers a fresh look at pesticide monitoring and has the potential to prevent pesticide-related health issues.

Two decades of the EU Water Framework Directive: Evidence of success and failure from a lowland arable catchment (River Wensum, UK)

The EU Water Framework Directive (WFD) is widely regarded as a seminal piece of environmental legislation. However, two decades since its inception, many European waterbodies are failing to meet its ambitious goal to ensure 'good' quantitative and qualitative status. Here, we investigate the impact of the WFD upon the environmentally sensitive yet heavily impacted River Wensum, a lowland arable catchment in eastern England. Compiling a dataset of 10,950 water quality samples collected from 57 sites across the catchment at approximately monthly intervals during 2000-2022, we assess the spatio-temporal dynamics of 12 priority pollutants, identify the major drivers of water quality change, and evaluate current and future compliance with WFD goals. Our analysis reveals improvements in wastewater treatment initiated significant declines (11-50 %) in the concentration of key sewage pollution indicators (phosphorus, ammonium, biological oxygen demand (BOD)) during the early 2000s. Conversely, agricultural pollution indicators (nitrogen, suspended solids, pesticides) displayed either limited change or a deterioration in water quality, with oxidised nitrogen concentrations in particular having increased 23 % during 2015-2022. Concentration spikes of organic chemical contaminants in recent years (propyzamide, tetrachloroethylene) raise concerns about increased riverine pollution from hazardous substances. Similarly, changes in winter (+13 %) and summer (-7 %) discharge over the past two decades have increased the risk of diffuse pollution mobilisation and reduced the dilution of point source pollutants, respectively. By 2022, 'good' or 'high' water quality status for organic matter pollution indicators (dissolved oxygen, BOD, ammonium) was achieved for >98 % of samples, however WFD compliance fell to just 46 % for phosphorus and 1.8 % for nitrogen. Projections to the end of the third River Basin Management Plan cycle (2027) reveal that whilst phosphorus compliance is likely to improve, nitrogen compliance failure will persist due to the existence of catchment legacy stores and climate change induced impacts on nitrogen mobilisation.

Occurrence, spatial distribution, and potential risks of organic micropollutants in urban surface waters from qinghai, northwest China

Lack of knowledge on the destiny of organic micropollutants (OMPs) in the Tibetan Plateau region of China prevents the public from being aware of the need for protecting these unique aquatic ecosystems that are precious water resources and source areas of the Yellow River. To address this knowledge gap, this study systematically investigated the multi-residue analysis, distribution, and potential risks of six types of OMPs, namely, neonicotinoid pesticides (NEOs), fungicides, organophosphate esters (OPEs), organophosphorus pesticides (OPPs), psychoactive substances (PSs), and antidepressants (ADs), in surface waters of major cities in Qinghai. A total of 31 compounds, consisting of 8 NEOs, 1 fungicide, 12 OPEs, 2 OPPs, 5 PSs, and 3 ADs, were detected in >50% of the sites, showing their ubiquitous nature in the study area. Results showed that the total OMP concentration in surface water was 28.3-908 ng/L, and OPEs were the dominant composition (48.6%-97.4%). The risk quotient values of the detected diazinon and dursban regularly exceeded 1 for aquatic organisms at all sampling sites, indicating moderate-high chronic ecological risk. The joint probability curves showed that dursban and NEOs have higher risk levels than other OMPs. Although the results of the non-carcinogenic total hazard quotient of the OMPs in the surface water was less than 1 in all age groups and the carcinogenic risk was lower than the negligible risk level, the potential risks to children and infants were considerably greater and should not be underestimated. In addition to pollutant concentration and exposure duration, ingestion rate and body weight (BW) are also important factors affecting health risk, with BW having a negative effect. To the best of the authors' knowledge, this report is the first to describe OMP pollution in Qinghai, and the results provide new insight into the ecological security of the water resources of the Tibetan Plateau.

Deep learning-based method for automatic resolution of gas chromatography-mass spectrometry data from complex samples

Modern gas chromatography-mass spectrometry (GC-MS) is the workhorse for the high-throughput profiling of volatile compounds in complex samples. It can produce a considerable amount of two-dimensional data, and automatic methods are required to distill chemical information from raw GC-MS data efficiently. In this study, we proposed an Automatic Resolution method (AutoRes) based on pseudo-Siamese convolutional neural networks (pSCNN) to extract the meaningful features swamped by the noises, baseline drifts, retention time shifts, and overlapped peaks. Two pSCNN models were trained with 400,000 augmented spectral pairs, respectively. They can predict the selective region (pSCNN1) and elution region (pSCNN2) of compounds in an untargeted manner. The accuracies of the pSCNN1 model and the pSCNN2 model on their test sets are 99.9% and 92.6%, respectively. Then, the chromatographic profile of each component was automatically resolved by full rank resolution (FRR) based on the predicted regions by these models. The performance of AutoRes was evaluated on the simulated and plant essential oil datasets. Compared to AMDIS and MZmine, AutoRes resolves more reasonable mass spectra, chromatograms, and peak areas to identify and quantify compounds. The average match scores of AutoRes (925 and 936) outperformed AMDIS (909 and 925) and MZmine (888 and 916) when resolving mass spectra from overlapped peaks on the Set Ⅰ and Set Ⅱ of plant essential oil dataset and matching them against the NIST17 library. It extracted peak areas and mass spectra automatically from 10 GC-MS files of plant essential oils, and the entire process was completed in 8 min without any prior information or manual intervention. It is implemented in Python and is available as an open-source package at https://github.com/dyjfan/AutoRes.

A new on-line SPE LC-HRMS method for simultaneous analysis of selected emerging contaminants in surface waters

In recent years emerging contaminants (ECs) have received significant attention due to their widespread detection in surface waters and concerns that these compounds can cause adverse ecological and/or human health effects. Therefore, accurate methods for determining and quantifying ECs in surface water are essential for estimating their environmental impact. This work describes the development, validation and application of a sensitive multiclass method for simultaneous determination of 22 per and polyfluorinated alkyl substances (PFASs), 3 pharmaceuticals, 15 pesticides, and 2 bisphenols in surface water using on-line solid phase extraction (SPE) coupled with ultra-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). The method allows simultaneous sample clean-up from interfering matrices and lower limits of detection (LODs) by injecting a large sample volume into the LC system without compromising chromatographic efficiency and resolution. Linearity of response over several orders of magnitude was demonstrated for all tested compounds (R2 > 0.99), with the LODs ranging from 0.8 and 33.7 pg mL-1, allowing detection of ECs at trace levels in surface water. The method showed acceptable accuracy and precision (CV, % and RE below 20%) for all tested ECs. It also provided recoveries between 60% and 130% for all tested ECs. The validated method was successfully applied for analysis of surface water samples from three rivers (Cam, Ouse and Thames) in England. Several ECs, including perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS), perfluorohexanoic acid (PFHxA), perfluorohexane sulfonic acid (PFHxS), dimethyl-metatoluamide (DEET) and ibuprofen were observed in analysed surface water above the method's limit of quantitation (LOQ), with concentrations ranging between 3.5 and 460 pg mL-1.

Pharmaceutical pollution of hospital effluents and municipal wastewaters of Eastern Canada

Quantification of drugs residues in wastewaters of different sources could help better understand contamination pathways, eventually leading to effluent regulation. However, limited data are available for hospital-derived wastewaters. Here, an analytical method based on automated on-line solid-phase extraction liquid chromatography tandem mass spectrometry (on-line SPE - UPLC-MS/MS) was developed for the quantification of multi-class pharmaceuticals in wastewaters. Filtrate phase and suspended solids (SPM) were both considered to evaluate the distribution of targeted analytes. Experimental design optimization involved testing different chromatographic columns, on-line SPE columns, and loading conditions for the filtrate phase, and different organic solvents and cleanup strategies for suspended solids. The selected methods were validated with suitable limits of detection, recovery, accuracy, and precision. A total of 30 hospital effluents and 6 wastewater treatment plants were sampled to evaluate concentrations in real field-collected samples. Certain pharmaceuticals were quantified at high levels such as caffeine at 670,000 ng/L in hospital wastewaters and hydroxyibuprofen at 49,000 ng/L in WWTP influents. SPM samples also had high contaminant concentrations such as ibuprofen at 31,000 ng/g in hospital effluents, fluoxetine at 529 ng/g in WWTP influents or clarithromycin at 295 ng/g in WWTP effluents. Distribution coefficients (K_d) and particle-associated fractions (Φ) indicate that pharmaceuticals tend to have better affinity to suspended solids in hospital wastewater than in municipal wastewaters. The results also bring arguments for at source treatment of these specific effluents before their introduction into urban wastewater systems.

Visible Light-Driven Advanced Oxidation Processes to Remove Emerging Contaminants from Water and Wastewater: a Review

The scientific data review shows that advanced oxidation processes based on the hydroxyl or sulfate radicals are of great interest among the currently conventional water and wastewater treatment methods. Different advanced treatment processes such as photocatalysis, Fenton's reagent, ozonation, and persulfate-based processes were investigated to degrade contaminants of emerging concern (CECs) such as pesticides, personal care products, pharmaceuticals, disinfectants, dyes, and estrogenic substances. This article presents a general overview of visible light-driven advanced oxidation processes for the removal of chlorfenvinphos (organophosphorus insecticide), methylene blue (azo dye), and diclofenac (non-steroidal anti-inflammatory drug). The following visible light-driven treatment methods were reviewed: photocatalysis, sulfate radical oxidation, and photoelectrocatalysis. Visible light, among other sources of energy, is a renewable energy source and an excellent substitute for ultraviolet radiation used in advanced oxidation processes. It creates a high application potential for solar-assisted advanced oxidation processes in water and wastewater technology. Despite numerous publications of advanced oxidation processes (AOPs), more extensive research is needed to investigate the mechanisms of contaminant degradation in the presence of visible light. Therefore, this paper provides an important source of information on the degradation mechanism of emerging contaminants. An important aspect in the work is the analysis of process parameters affecting the degradation process. The initial concentration of CECs, pH, reaction time, and catalyst dosage are discussed and analyzed. Based on a comprehensive survey of previous studies, opportunities for applications of AOPs are presented, highlighting the need for further efforts to address dominant barriers to knowledge acquisition.

Occurrence, distribution and risk assessment of organophosphate esters (OPEs) in water sources from Northeast to Southeast China

With the wide utilization of organophosphate esters (OPEs) in recent years, OPEs have been detected more frequently in the aquatic environment. However, the distribution of OPEs in drinking source water has rarely been investigated across a large region. In this study, the occurrence and distribution of 13 OPEs were investigated in 23 source water sites from Northeast to Southeast (spacing greater than 3320 km) with a direct injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. Total OPEs ranged from 218.8 to 636.6 ng/L, with a mean of 380.8 ng/L. The average detected concentration of OPEs in southern cities was higher than that in northern cities. Chlorinated OPEs accounted for 64.74% of the total concentration. Triethyl phosphate (TEP), tri (2-chloroethyl) phosphate (TCEP), and tri (chloropropyl) phosphate (TCPP) were detected in all water samples. Rainfall is a significant factor that affects the OPE concentration (less rainfall, higher concentration). China's OPE concentrations have rapidly reached a median level when compared to those of other countries. Ecological risk assessment showed that most OPEs have no or low risk to organisms (fish, crustacea, algae), except tricresyl phosphate (TCP), which is medium risk. The risk of OPEs in less-rain regions needs to be of greater concern, especially TCP.

Target and suspect screening of 4777 per- and polyfluoroalkyl substances (PFAS) in river water, wastewater, groundwater and biota samples in the Danube River Basin

Per- and polyfluoroalkyl substances (PFAS) are under regulatory scrutiny since some of them are persistent, bioaccumulative, and toxic. The occurrence of 4777 PFAS was investigated in the Danube River Basin (DRB; 11 countries) using target and suspect screening. Target screening involved investigation of PFAS with 56 commercially available reference standards. Suspect screening covered 4777 PFAS retrieved from the NORMAN Substance Database, including all individual PFAS lists submitted to the NORMAN Suspect List Exchange Database. Mass spectrometry fragmentation patterns and retention time index predictions of the studied PFAS were established for their screening by liquid chromatography - high resolution mass spectrometry using NORMAN Digital Sample Freezing Platform (DSFP). In total, 82 PFAS were detected in the studied 95 samples of river water, wastewater, groundwater, biota and sediments. Suspect screening detected 72 PFAS that were missed by target screening. Predicted no effect concentrations (PNECs) were derived for each PFAS via a quantitative structure-toxicity relationship (QSTR)-based approach and used for assessment of their environmental risk. Risk characterization revealed 18 PFAS of environmental concern in at least one matrix. The presence of PFAS in all studied environmental compartments across the DRB indicates a potentially large-scale migration of PFAS in Europe, which might require their further systematic regulatory monitoring.

A new and systematic review on the efficiency and mechanism of different techniques for OPFRs removal from aqueous environments

Organic phosphorus flame retardants (OPFRs), as a new type of emerging contaminant, have drawn great attention over the last few years, due to their wide distribution in aquatic environments and potential toxicities to humans and living beings. Various treatment methods have been reported to remove OPFRs from water or wastewater. In this review, the performances and mechanisms for OPFRs removal with different methods including adsorption, oxidation, reduction and biological techniques are overviewed and discussed. Each technique possesses its advantage and limitation, which is compared in the paper. The degradation pathways of typical OPFRs pollutants, such as Cl-OPFRs, alkyl OPFRs and aryl OPFRs, are also reviewed and compared. The degradation of those OPFRs depends heavily upon their structures and properties. Furthermore, the implications and future perspectives in such area are discussed. The review may help identify the research priorities for OPFRs remediation and understand the fate of OPFRs during the treatment processes.

Toxicity of di-2-ethylhexyl phthalate and tris (2-butoxyethyl) phosphate to a tropical micro-crustacean (Ceriodaphnia cornuta) is higher in Mekong River water than in standard laboratory medium

Plasticizers such as di(2-ethylhexyl) phthalate (DEHP) and tris (2-butoxyethyl) phosphate (TBOEP) are manufactured chemicals produced in high volumes. These chemicals are frequently detected in the aquatic environment and cause toxic effects on organisms. In this study, we assessed the chronic impacts of DEHP and TBOEP, respectively, at the concentration of 100 µg L^-1 dissolved in the artificial medium (M4/4) and Mekong River water on life history traits of a tropical micro-crustacean, Ceriodaphnia cornuta, for 14 days. DEHP and TBOEP substantially reduced the survival of C. cornuta. In M4/4 medium, both plasticizers strongly enhanced reproduction but did not influence the growth of C. cornuta. Mekong River water, plasticizers-exposed C. cornuta produced less neonates than those in the control. The detrimental impacts of DEHP and TBOEP on the fitness of C. cornuta were much stronger in natural river water than in M4/4. Our results suggest that plasticizers can cause adverse effects on tropical freshwater cladocerans, particularly in natural water. These results are of a deep concern, as national and international regulatory guidelines which are based on ecotoxicological tests using standard media may not fully capture these effects.

Global occurrence and probabilistic environmental health hazard assessment of per- and polyfluoroalkyl substances (PFASs) in groundwater and surface waters

Per- and polyfluoroalkyl substances (PFASs) have been used in consumer and military products since the 1950s but are increasingly scrutinized worldwide because of inherent chemical properties, environmental contamination, and risks to public health and the environment. The United States Environmental Protection Agency (USEPA) identified 24 PFASs of interest for further study and possible regulation. We examined 371 peer-reviewed studies published since 2001 to understand the occurrence and distribution of 24 priority PFASs in global surface waters and groundwater. We identified 77,541 and 16,246 data points for surface waters and groundwater, respectively, with total PFAS concentrations ranging from low pg/L to low mg/L levels. Most data were from Asia, Europe, and North America with some reports from Oceania. PFAS information from other geographic regions is lacking. PFASs levels are consistently higher in rivers and streams followed by lakes and reservoirs and then coastal and marine systems. When sufficient data were available, probabilistic environmental hazard assessments (PEHAs) were performed from environmental exposure distributions (EEDs) to identify potential exceedances of available guideline values for each compound by matrix, region, and aquatic system. Specifically, exceedances of USEPA drinking water lifetime health advisory levels were up to 74% for PFOS in groundwater from Oceania and 69% for PFOA in North American groundwater. Our findings support selection of environmentally relevant experimental treatment levels for future toxicology, ecotoxicology and bioaccumulation studies, and potable source water exposure investigations, while highlighting PFASs and major geographic locations requiring additional study and inclusion in global monitoring and surveillance campaigns.

Evaluation of cytogenotoxic potential and embryotoxicity of KRS-Cauvery River water in zebrafish (Danio rerio)

In the Cauvery River (CR), indiscriminate discharge of waste causes unexplained skeletal deformity in some fish species present in the water. To investigate this phenomenon, we analyzed the biological, physical, and chemical parameters present in the water and then evaluated the toxicity effects on the zebrafish (Danio rerio) model. The zebrafish were treated with KRS-CR water samples collected from three stations (fast-flowing water [X], slow-flowing [Y], and stagnant [Z] water), before and after filtration. Firstly, we detected microscopic organisms (MO) such as Cyclops, Daphnia, Spirogyra, Spirochaeta, and total coliform (Escherichia coli), which are bioindicators of water pollution present in the samples. All physicochemical parameters analyzed, including heavy metals before and after filtration of the water with Millipore filter paper (0.45 µm), were within the acceptable limits set by standard organizations, except for decreased dissolved oxygen (DO), and increased biochemical oxygen demand (BOD), and chemical oxygen demand (COD), which are indicators of hypoxic water conditions, as well as the presence of microplastics (polybutene (< 15 µm), polyisobutene (≤ 20 µm), and polymethylpentene (≤3 mm)) and cyclohexyl in CR water samples. Zebrafish embryos treated with the water samples, both before and after filtration exerts the same cytogenotoxic effects by inducing increased reactive oxygen species (ROS) production, which triggers subcellular organelle dysfunctions, DNA damage, apoptosis, pericardial edema, skeletal deformities, and increased mortality. As a result, we observed that both water samples and zebrafish larvae had significantly less oxygen using SEM and EDS. Our findings show that KRS-CR water can induce cytogenotoxic and embryotoxic defects in zebrafish due to hypoxic water conditions triggered by the microplastics influx. The present study would provide valuable insights for health hazards evaluation and future river water treatment strategies.

Long-Term Trends of Per- and Polyfluoroalkyl Substances (PFAS) in Suspended Particular Matter from German Rivers Using the Direct Total Oxidizable Precursor (dTOP) Assay

Suspended particulate matter (SPM) from 13 riverine sampling sites of the German Environmental Specimen Bank collected between 2005 and 2019 was retrospectively investigated for per- and polyfluoroalkyl substances (PFAS). The samples were analyzed both by target analysis for 41 PFAS and by a modified total oxidizable precursor (dTOP) assay to capture also unknown precursors. Temporal trends and spatial differences were investigated by generalized linear modeling (GLM). Time trend analysis across all rivers showed decreasing trends for ∑PFCA and ∑PFSA concentrations in SPM. Trends based on target analysis (∑PFCA_target: -10.0%, ∑PFSA_target: -8.2%) were more pronounced than in the dTOP analysis (∑PFCA_dTOP: -4.2%; ∑PFSA_dTOP: -5.3%), suggesting that conventional target analysis overestimated actual decreases as precursors are not considered. ∑PFAS concentrations determined by dTOP assay were 1.3-145 times higher as compared to target analysis, indicating substantial amounts of unknown precursors in the samples. The ∑PFAS_dTOP/∑PFAS_target ratio increased at all sites between 2005 and 2019. Contamination was highest in SPM from the Elbe tributary Mulde downstream of a large industrial park. The results underscore the need to go beyond conventional target analysis and include precursors when assessing PFAS contamination in the environment. The dTOP assay is a suitable tool for this purpose.

Levels and trends of perfluoroalkyl acids (PFAAs) in water (2013-2020) and fish from selected riverine basins in Spain

The aim of the present study was to assess the presence of perfluoroalkyl acids (PFAAs), namely perfluoroalkane sulfonates and perfluoroalkyl carboxylic acids, in Spanish river basins in order to: identify potential spatiotemporal variations; evaluate the effectiveness of the measures implemented for the reduction/elimination of these pollutants; verify the fulfillment of the Environmental Quality Standards (EQSs) in the European Union. PFOS and PFOA were determined in 116 water samples from four sites in the Duero basin, the largest in the Iberian Peninsula, collected seasonally from 2013 to 2020. In addition, 30 fish sample composites from the sample banks of Duero, Tagus, Ebro, Eastern Cantabrian and Catalonian basins were analyzed for 15 PFAAs. Median PFOS and PFOA concentrations were 0.72 and 0.42 ng/L, ranging from values below the limit of quantification (LOQ) to 81 and 22 ng/L, respectively. During the studied period, 51% of water samples were above the EQS of 0.65 ng/L for PFOS. In the case of fish, the PFOS range was <LOQ-59 with 33% of the samples above the EQS of 9.1 ng/g wet weight. Moreover, fish from the Tagus and Catalonian basins showed median concentrations above the EQS. Particularly, fish collected around highly populated areas such as Madrid and Barcelona showed the greatest PFAA concentrations. Overall, PFAA concentrations in water and fish increased significantly with population density suggesting urban areas as their main source. Although our results suggested decreasing tendencies for PFOS and PFOA in water, significant trends only could be confirmed at two sampling sites.

Effects of common environmental endocrine-disrupting chemicals on zebrafish behavior

Environmental endocrine-disrupting chemicals (EDCs), a type of exogenous organic pollutants, are ubiquitous in natural aquatic environments. Therefor, this review focused on the use of the zebrafish as a model to explore the effect of different EDCs on behavior, as well as the molecular mechanisms that drive these effects. Furthermore, our study summarizes the current knowledge on the neuromodulatory effects of different EDCs in zebrafish. This study also reviews the current state of zebrafish behavior research, in addition to the potential mechanisms of single and mixed pollutant-driven behavioral dysregulation at the molecular level, as well as the applications of zebrafish behavior experiments for neuroscience research. This review broadens our understanding of the influence of EDCs on zebrafish behavior and provides guidance for future research.

Occurrence and risk assessment of organophosphate esters in urban rivers from Piracicaba watershed (Brazil)

Organophosphate esters (OPEs) are substances globally used as flame retardants and plasticizers that have been detected in all environmental compartments. This study aimed to evaluate the occurrence and sources of ten OPEs in the Piracicaba River Basin (Brazil). Twelve sampling sites were selected in five rivers with different pollution sources; six sampling campaigns were performed encompassing dry and wet seasons. ΣOPEs ranged from 0.12 to 6.2 μg L^-1; the levels in urban areas were higher than in rural and non-urban areas, but no overall tendency concerning the seasonal effect on OPEs concentrations was observed. Tris(2-butoxyethyl) phosphate (TBOEP), tris(2-chloroisopropyl) phosphate (TCIPP), and tris(1,3-dichloroisopropyl) phosphate (TDCIPP) were the most abundant and frequently detected compounds. Nine OPEs were detected at higher concentrations in a site affected by effluents from textile industries. An acute toxicity test using Daphnia similis was performed for tris(2-ethylhexyl) phosphate (TEHP) for the calculation of a preliminary predicted no effect concentration (PNEC). The risk quotient (RQ) approach was applied and risk to aquatic environment related to TEHP levels was observed in areas adjacent to textile industries, but more toxicity studies are required for the determination of a more reliable PNEC.

Detection and removal of poly and perfluoroalkyl polluting substances for sustainable environment

PFAs (poly and perfluoroalkyl compounds) are hazardous and bioaccumulative chemicals that do not readily biodegrade or neutralize under normal environmental conditions. They have various industrial, commercial, domestic and defence applications. According to the Organization for Economic Co-operation and Development, there are around 4700 PFAs registered to date. They are present in every stream of life, and they are often emerging and are even difficult to be detected by the standard chemical methods. This review aims to focus on the sources of various PFAs and the toxicities they impose on the environment and especially on humankind. Drinking water, food packaging, industrial areas and commercial household products are the primary PFAs sources. Some of the well-known treatment methods for remediation of PFAs presented in the literature are activated carbon, filtration, reverse osmosis, nano filtration, oxidation processes etc. The crucial stage of handling the PFAs occurs in determining and analysing the type of PFA and its remedy. This paper provides a state-of-the-art review of determination & tools, and techniques for remediation of PFAs in the environment. Improving new treatment methodologies that are economical and sustainable are essential for excluding the PFAs from the environment.

Emerging and Persistent Pollutants in the Aquatic Ecosystems of the Lower Danube Basin and North West Black Sea Region—A Review

The tremendous impact of natural and anthropogenic organic and inorganic substances continuously released into the environment requires a better understanding of the chemical status of aquatic ecosystems. Water contamination monitoring studies were performed for different classes of substances in different regions of the world. Reliable analytical methods and exposure assessment are the basis of a better management of water resources. Our research comprised publications from 2010 regarding the Lower Danube and North West Black Sea region, considering regulated and unregulated persistent and emerging pollutants. The frequently reported ones were: pharmaceuticals (carbamazepine, diclofenac, sulfamethoxazole, and trimethoprim), pesticides (atrazine, carbendazim, and metolachlor), endocrine disruptors—bisphenol A and estrone, polycyclic aromatic hydrocarbons, organochlorinated pesticides, and heavy metals (Cd, Zn, Pb, Hg, Cu, Cr). Seasonal variations were reported for both organic and inorganic contaminants. Microbial pollution was also a subject of the present review.

A Comparative Test on the Sensitivity of Freshwater and Marine Microalgae to Benzo-Sulfonamides, -Thiazoles and -Triazoles

The evaluation of the ecotoxicological effects of water pollutants is performed by using different aquatic organisms. The effects of seven compounds belonging to a class of widespread contaminants, the benzo-fused nitrogen heterocycles, on a group of simple organisms employed in reference ISO tests on water quality (unicellular algae and luminescent bacteria) have been assessed to ascertain their suitability in revealing different contamination levels in the water, wastewater, and sediments samples. Representative compounds of benzotriazoles, benzothiazoles, and benzenesulfonamides, were tested at a concentration ranging from 0.01 to 100 mg L−1. In particular, our work was focused on the long-term effects, for which little information is up to now available. Species-specific sensitivity for any whole family of pollutants was not observed. On average, the strongest growth rate inhibition values were expressed by the freshwater Raphidocelis subcapitata and the marine Phaeodactylum tricornutum algae. R. subcapitata was the only organism for which growth was affected by most of the compounds at the lowest concentrations. The tests on the bioluminescent bacterium Vibrio fisheri gave completely different results, further underlining the need for an appropriate selection of the best biosensors to be employed in biotoxicological studies.

Diclofenac modified the root system architecture of Arabidopsis via interfering with the hormonal activities of auxin

Diclofenac, a pharmaceutical and personal care product, is accumulating in various environmental matrices worldwide. Increased irrigation has facilitated an influx of environmental diclofenac into agricultural products, which potentially threatens non-target living organisms. In this study, we demonstrated that diclofenac modified the growth and root developmental processes of plants by disturbing the activity of auxin, a group of major phytohormones. Exogenous diclofenac treatment retarded growth and induced oxidative stress in young seedlings of Arabidopsis thaliana. In the developmental perspective, diclofenac altered the root system architecture, which was also similarly observed under exogenous IAA (a natural form of phytoalexins) treatment. The effects of diclofenac on the root development of A. thaliana were mediated through canonical auxin signaling pathways. However, when diclofenac and IAA were treated in combination, diclofenac suppressed the activity of IAA in root system architecture. At the molecular level, diclofenac significantly inhibited the activity of IAA upregulating the expression of early auxin-responsive marker genes. In conclusion, diclofenac modified the root development of A. thaliana via interfering with the activities of natural auxin. These results indicate that diclofenac could potentially act as an environmental contaminant disturbing the natural developmental processes of plants.

Photocatalytic degradation of diclofenac using TiO2-CdS heterojunction catalysts under visible light irradiation

The present study reports the photocatalytic degradation of analgesic drug diclofenac using the hydrothermally prepared TiO₂-CdS heterojunction catalyst. The results suggest that the prepared catalysts exhibited excellent photocatalytic activity under visible light irradiation. The photodegradation kinetics were well fitted to the pseudo-first-order reaction. The apparent reaction rate constant for TC5 catalyst in the diclofenac degradation was 0.02316 min^-1. Mineralisation of diclofenac using TC5 photocatalyst was around 86% within 4 h of irradiation time. The operating parameters such as optimal catalyst dosage, apparent solution pH and the effect of initial diclofenac concentration were also studied using the TC5 catalyst. The role of active species in the degradation mechanism was elucidated and it was found that the hydroxyl radical is the main active species in the diclofenac degradation mechanism. The charge transfer between heterojunction catalysts is facilitated by direct Z-scheme heterojunction structure. The coupled photocatalysts also showed good photochemical stability and reusability over five successive reaction cycles. The tentative degradation pathway has been devised based on LC-MS peaks, and it is found that only m/z 224, m/z 178 and m/z 124 were persisted at the end of the reaction.

Neural stem cell-based in vitro bioassay for the assessment of neurotoxic potential of water samples

Intensive agriculture activities, industrialization and growing numbers of wastewater treatment plants along river banks collectively contribute to the elevated levels of neurotoxic pollutants in natural water reservoirs across Europe. We established an in vitro bioassay based upon neural stem cells isolated from the subventricular zone of the postnatal mouse to evaluate the neurotoxic potential of raw wastewater, treated sewage effluent, groundwater and drinking water. The toxic potential of water samples was evaluated employing viability, proliferation, differentiation and migration assays. We found that raw wastewater could reduce the viability and proliferation of neural stem cells, and decreased the neuronal and astrocyte differentiation, neuronal neurite growth, astrocyte growth and cell migration. Treated sewage water also showed inhibitory effects on cell proliferation and migration. Our results indicated that relatively high concentrations of nitrogenous substances, pesticides, mercuric compounds, bisphenol-A, and phthalates, along with some other pollutants in raw wastewater and treated sewage water, might be the reason for the neuroinhibitory effects of these water samples. Our model successfully predicted the neurotoxicity of water samples collected from different sources and also revealed that the incomplete removal of contaminants from wastewater can be problematic for the developing nervous system. The presented data also provides strong evidence that more effective treatments should be used to minimize the contamination of water before release into major water bodies which may be considered as water reservoirs for human usage in the future.

Approaches to herbicide (MCPA) pollution mitigation in drinking water source catchments using enhanced space and time monitoring

Freshwater occurrences of the selective acid herbicide 2-methyl-4-chloro-phenoxyacetic acid (MCPA) are an ongoing regulatory and financial issue for water utility industries as the number and magnitude of detections increase, particularly in surface water catchments. Assessments for mitigating pesticide pollution in catchments used as drinking water sources require a combination of catchment-based and water treatment solutions, but approaches are limited by a lack of empirical data. In this study, an enhanced spatial (11 locations) and temporal (7-hourly to daily sampling) monitoring approach was employed to address these issues in an exemplar surface water source catchment (384 km²). The spatial sampling revealed that MCPA was widespread, with occurrences above the 0.1 μg L^-1 threshold for a single pesticide being highly positively correlated to sub-catchments with higher proportions of 'Improved Grassland' land use (r = 0.84). These data provide a strong foundation for targeting catchment-based mitigation solutions and also add to the debate on the ecosystems services provided by such catchments. Additionally, of the 999 temporal samples taken over 12 months from the catchment outlet, 25% were above the drinking water threshold of 0.1 μg L^-1. This prevalence of high concentrations presents costly problems for source water treatment. Using these data, abstraction shutdowns were simulated for five scenarios using hydrometeorological data to explore the potential to avoid intake of high MCPA concentrations. The scenarios stopped abstraction for 4.2-9.3% of the April-October period and reduced intake of water containing over 0.1 μg L^-1 of MCPA by 16-31%. This represents an important development for real-time proxy assessments for water abstraction in the absence of more direct pesticide monitoring data.

Double constrained ordination for assessing biological trait responses to multiple stressors: A case study with benthic macroinvertebrate communities

Benthic macroinvertebrate communities are used as indicators for anthropogenic stress in freshwater ecosystems. To better understand the relationship between anthropogenic stress and changes in macroinvertebrate community composition, it is important to understand how different stressors and species traits are associated, and how these associations influence variation in species occurrence and abundances. Here, we show the capacity of the multivariate technique of double constrained correspondence analysis (dc-CA) to analyse trait-environment relationships, and we compare it with the redundancy analysis method on community weighted mean values of traits (CWM-RDA), which is frequently used for this type of analysis. The analyses were based on available biomonitoring data for macroinvertebrate communities from the Danube River. Results from forward selection of traits and environmental variables using dc-CA analyses showed that aquatic stages, reproduction techniques, dispersal tactics, locomotion and substrate relations, altitude, longitudinal and transversal distribution, and substrate preferendum were significantly related to habitat characteristics, hydromorphological alterations and water quality measurements such as physico-chemical parameters, heavy metals, pesticides and pharmaceuticals. Environmental variables significantly associated with traits using the CWM-RDA method were generally consistent with those found in dc-CA analysis. However, the CWM-RDA does neither test nor explicitly select traits, while dc-CA tests and selects both traits and environmental variables. Moreover, the dc-CA analysis revealed that the set of environmental variables was much better in explaining the community data than the available trait set, a kind of information that can neither be obtained from CWM-RDA nor from RLQ (Environment, Link and Trait data), which is a close cousin of dc-CA but not regression-based. Our results suggest that trait-based analysis based on dc-CA may be useful to assess mechanistic links between multiple anthropogenic stressors and ecosystem health, but more data sets should be analysed in the same manner.

Simultaneous determination of seven perfluoroalkyl carboxylic acids in water samples by 2,3,4,5,6-pentafluorobenzyl bromide derivatization and gas chromatography-mass spectrometry

A new derivatization reagent, 2,3,4,5,6-pentafluorobenzyl bromide (PFBBr), was employed to determine seven perfluoroalkyl carboxylic acids (PFCAs) simultaneously in tap water with gas chromatography-mass spectrometry (GC-MS) technique in this study. Firstly, seven PFCAs were derivatized to their corresponding esters under alkaline condition. The derivatization conditions including the amount of PFBBr and K₂CO₃, derivatization temperature and time were optimized to increase the derivatization efficiency. The 14 tap water samples collected from different places of China were enriched and purified through solid phase extraction pretreatment. The limits of detection (LODs) and the limits of quantitation (LOQs) ranged from 0.1 ng/L to 0.28 ng/L and from 0.3 ng/L to 0.84 ng/L, respectively. The new method offers a linear relationship in the range from 2 ng/L to 2000 ng/L, and the correlation coefficients ranged from 0.9938 to 0.9994. The results showed that GC-MS combined with pre-column derivatization is a reliable method for the analysis of PFCAs in the aqueous environment.

Diet quality and NSAIDs promote changes in formation of prostaglandins by an aquatic invertebrate

We used the freshwater insect Hydropsyche sp. to investigate the impact of diets lacking arachidonic acid (ARA) and an environmentally relevant mixture of NSAIDs (Ibuprofen, Ketoprofen, Diclofenac and Naproxen at a nominal concentration of all compounds together 16.75 μg L^-1) on their metabolism of ARA and prostaglandins (PGs). The organisms were exposed for 16 days to four different treatments: a reference (FF), a diet lacking ARA (O), to NSAIDs in water (FFN) and to the combination of the two factors (ON). Mortality, biomass and bioconcentration of pharmaceuticals were investigated. The ARA and PGs levels in the organisms were monitored by utilising a targeted metabolomics approach. NSAIDs or dietary constraints did not produce significant differences in biomass or mortality of Hydropsyche sp. among treatments. In organisms exposed to NSAIDs, all pharmaceuticals were detected, except for Ketoprofen. Metabolomic approach determined the presence of PGH₂, PGE₁ and PGD₁. Levels of ARA diminished significantly in those organisms in treatment ON. The levels of PGs responded negatively to the absence of ARA in diet: PGH₂ diminished significantly with respect to the reference in treatment O while PGE₁ diminished significantly in treatment ON. Regarding the effects of NSAIDs on ARA metabolism, our results suggest that it was sensitive to NSAIDs, but effects were weak and did not imply a general decrease in the PGs. We confirmed that ARA was the main substrate for the synthesis of PGs in Hydropsyche sp, their absence or poor levels of ARA in diet, produced changes in the PG levels.

Multiplexed Immunosensor Based on the Amperometric Transduction for Monitoring of Marine Pollutants in Sea Water

Environmental pollutants vigilance is one of the main problems that the aquaculture industry has to face with the objective to ensure the quality of their products and prevent entrance in the food chain that finally may arrive to the consumer. Contaminants such as hormones, antibiotics or biocides are especially relevant due to their toxicity, pharmacological effect or hormonal activity that can be considered harmful for the final consumer. The contaminants can be detected in the environment where the food is growing, and their concentration can be found (i.e., seawater) in the range of µg·L⁻¹, ng·L⁻¹ or even in lower concentrations. Thus, sensitive and selective methods for their monitoring are required to avoid their arrival in the food chain. Here, the development of a multiplexed amperometric biosensor is described, based on the use of specific antibodies to reach the necessary detectability to measure the targeted contaminants directly in seawater. The multiplexed immunosensor allows the detection of four relevant pollutants, such as el Irgarol 1051, sulfapyridine, chloramphenicol and estradiol, reaching an IC₅₀ of 5.04 ± 0.29, 3.45 ± 0.29, 4.17 ± 0.44 and 5.94 ± 0.28 µg·L⁻¹, directly measured in seawater.

Occurrence, spatial distribution and risk assessment of organophosphate esters in surface water from the lower Yangtze River Basin

Organophosphate esters (OPEs) are extensively used as flame retardants and plasticizers in China; however, their potential carcinogenicity causes great concern. To date, their environmental distribution in water samples from the lower Yangtze River Basin still remains uncharacterized. This study systematically investigated the occurrence and spatial distribution of 13 OPEs, as well as their associated potential risks, in water samples from the lower Yangtze River and its 88 major inflowing rivers. The total OPE (ΣOPEs) concentrations ranged from 55.6 to 5071 ng/L, with a median of 144 ng/L. Among them, halogenated OPEs were the dominant group with an average of 61.6%, and tris(1-chloro-2-propyl) phosphate (12.6-450 ng/L, median: 53.38 ng/L) and tris(2-choroethyl) phosphate (11.0-1202 ng/L, median: 36.4 ng/L) were the most abundant OPEs. Significantly different concentrations were found with spatial variations (p < 0.01), and were higher in southern cities than in northern cities of the lower Yangtze River Basin. Principal component analysis with multiple linear regression and Spearman correlations showed that the main sources were likely emission of vehicular and marine traffic. Ecological risk analysis showed that the risk quotient (RQ) values of samples remained below 1, but the percentage of 0.1 < RQ ≤ 1 was 26.9%, indicating a medium risk of OPEs in water samples. Moreover, ethylhexyl diphenyl phosphate predominantly contributed to the ecological risk, accounting for >89.2% of the total ecological risk of ΣOPEs. However, the total non-carcinogenic and carcinogenic risks of ΣOPEs were negligible at the detected concentrations, even in a high exposure scenario. The risks from major inflowing rivers of the lower Yangtze River were almost one order of magnitude higher than those of the mainstream lower Yangtze River.

A Simple Method for the Determination of Triazines from Seawater in Accordance with the Directive 2013/39/EU

Since the Directive 2013/39/EU included terbutryn to the list of priority substances of all water bodies, a previous method based on dispersive liquid-liquid micro-extraction (DLLME) for the determination of triazines in seawater has been modified. The main change consisted on the use of tandem mass spectrometry instead of diode array as detection technique. Due to the higher sensitivity of mass detector, sample volume was reduced and extraction solvent volume was optimized. The optimum extraction conditions were 5 mL of sample, 50 µL of 1-octanol and an agitation step instead of disperser solvent. The obtained analytical recoveries (73%-101% with relative standard deviations below 4%) meeting the requirements. The limits of quantification (between 0.016 and 0.021 µg L^-1) were more than 10 times lower than the limit set by the European Directive 2013/39/EU for terbutryn (0.34 µg L^-1). The proposed method was applied to the determination of the target compounds in seawater samples from A Coruña (Galicia, NW of Spain).

Spatial variation of 2,4-D and MCPA in tap water and groundwater from China and their fate in source, treated, and tap water from Wuhan, Central China

Data on chlorophenoxy herbicides (CPHs) in drinking water from China are scarce. This study was designed to describe the occurrence of CPHs in drinking water in China. In June 2019, drinking water samples including 789 tap water and 95 groundwater samples were collected from 31 provinces in mainland China and Hong Kong. Raw source, treated, and tap water samples (n = 20, 20, and 170, respectively) in Wuhan, Central China were also analyzed. 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) were found in 71.2% and 74.9% of the samples nationwide, respectively. The cumulative concentration of CPHs (ΣCPHs) in tap water in China was up to 125 ng/L (median: 1.38 ng/L), and regional variations were found for ΣCPHs. The highest median ΣCPHs (3.95 ng/L) was found in Northeast China, followed by Central (3.40), South (2.71), East (2.43), Southwest (1.58), North (0.42), and Northwest China (0.30). The median ΣCPHs in groundwater was approximately five times lower than that in tap water. In addition, ΣCPHs were found in all the raw source water samples collected in Wuhan, Central China (median: 6.69 ng/L, range: 2.66-43.1 ng/L). The removal of 2,4-D and MCPA during conventional drinking water treatment was not efficient, removing approximately 0.91% and 17.4%, respectively. In a water plant with advanced treatment, they were efficiently removed. Seasonal variations were found in ΣCPHs in tap water from Wuhan, with the highest found in July (median: 21.2 ng/L), and the lowest in October (1.96 ng/L). The intake of CPHs via water ingestion was estimated as below 5 ng/kg-bw/day, much lower than the reference doses for 2,4-D (5 μg/kg-bw/day) and MCPA (4 μg/kg-bw/day). This is the first study to demonstrate the fate of CPHs during drinking water treatment and seasonal variations of CPHs in water from Wuhan, China. Moreover, this study provides an overview of ΣCPHs in tap water for many areas in China.

Occurrence and assessment of environmental risks of endocrine disrupting compounds in drinking, surface and wastewaters in Serbia

The present study is the first comprehensive monitoring of 13 selected endocrine disrupting compounds (EDCs) in untreated urban and industrial wastewater in Serbia to assess their impact on the Danube River basin and associated freshwaters used as sources for drinking water production in the area. Results showed that natural and synthetic estrogens were present in surface and wastewater at concentrations ranging from 0.1 to 64.8 ng L^-1. Nevertheless, they were not detected in drinking water. For alkylphenols concentrations ranged from 1.1 to 78.3 ng L^-1 in wastewater and from 0.1 to 37.2 ng L^-1 in surface water, while in drinking water concentrations varied from 0.4 to 7.9 ng L^-1. Bisphenol A (BPA) was the most abundant compound in all water types, with frequencies of detection ranging from 57% in drinking water, to 70% in surface and 84% in wastewater. Potential environmental risks were characterized by calculating the risk quotients (RQs) and the estrogenic activity of EDCs in waste, surface and drinking water samples, as an indicator of their potential detrimental effects. RQ values of estrone (E1) and estradiol (E2) were the highest, exceeding the threshold value of 1 in 60% of wastewater samples, while in surface water E1 displayed potential risks in only two samples. Total estrogenic activity (EEQ_t) surpassed the threshold of 1 ng E2 L^-1 in about 67% of wastewater samples, and in 3 surface water samples. In drinking water, EEQ_t was below 1 ng L^-1 in all samples.

Occurrence, composition and biological risk of organophosphate esters (OPEs) in water of the Pearl River Estuary, South China

Since the production of brominated flame retardants has been gradually phased out, organophosphate esters (OPEs) are increasingly used as the substitutes. Given their toxicity and water solubility, OPEs may jeopardize the aquatic environment and organisms. Here, we examined the concentration, composition, and biological risk of OPEs in the water collected from the eight major waterways in the Pearl River Delta, a highly industrialized region in China. We found a widespread occurrence of OPEs in this region (∑₉OPEs: 134 to 442 ng L^-1), dominated by TCPP, TCEP, and TnBP. Halogenated OPEs were dominant over alkyl and aromatic OPEs. The biological risk of OPEs, mainly contributed by TPhP and TnBP, was low (RQ < 0.1). The contamination level of OPEs in the Pearl River Delta was likely associated with the degree of industrial activities. Although OPEs posed low risk to aquatic organisms, more attention should be paid to some OPEs in the future, such as TnBP, due to the high usage and toxicity. Considering the concentrations of OPEs worldwide and their usage, OPEs may become the emerging pollutants of global concern in the next decade.

Occurrence of organic plastic additives in surface waters of the Rhône River (France)

We present here a comprehensive study (1-year regular sampling) on the occurrence of major families of organic plastic additives in the Rhône River surface waters. Potential sources and contaminant export are also discussed. A total of 22 dissolved phase samples were analyzed for 22 organic additives mainly used in the plastic industry, including organophosphate esters (OPEs), phthalates (PAEs) and bisphenols (BPs). Our results indicate that PAEs were the most abundant class, with concentrations ranging from 97 to 541 ng L^-1, followed by OPEs (85-265 ng L^-1) and BPs (4-21 ng L^-1). Among PAEs, diethylhexyl phthalate (DEHP) was the most abundant compound, whereas TCPP (Tris(1-chloro-2-propyl) phosphate) and TnBP (Tri(n-butyl)phosphate) were the predominant OPEs. Bisphenol S was the only BP detected. 5-54 metric tons year^-1 of dissolved organic plastic additives of emerging concern are estimated to be exported to the Gulf of Lion by the Rhône River, which is the main freshwater source of the Mediterranean Sea.