A review toward contaminants of emerging concern in Brazil: Occurrence, impact and their degradation by advanced oxidation process in aquatic matrices

Electrochemical oxidation for the rapid degradation of emerging contaminants: Insights into electrolytes and process parameters for phytotoxicity reduction

Atrazine (ATZ), carbamazepine (CBZ), and sulfamethoxazole (SMX) are contaminants of emerging concern (CECs) commonly detected in water sources, posing a risk to health, sanitation, and the ecosystems. This study evaluates the degradation, mineralization, and phytotoxicity reduction of a solution containing these three CECs using an electrochemical advanced oxidation process (EAOP). Key operational parameters - pH, flow rate (Q), current density (j), and type and concentration of supporting electrolytes (NaCl and Na2SO4) - were systematically investigated. The results showed that pH had minimal impact on the process. Higher flow rates (250 L h-1) improved mineralization due to enhanced mass transfer to •OH on the anode surface. However, the flow rate had less effect on degradation, as the dominant degradation mechanisms involved chlorine- or sulfate-based oxidants. Current densities of 1 and 10 mA cm-2 produced the most favorable results, leading to efficient degradation and mineralization, along with satisfactory mineralization current efficiency (up to 47 %) and energy consumption values (91,76-3142,88 kW h kg-1). When NaCl was used as supporting electrolyte, the degradation of CECs was twice as fast as with Na2SO4, achieving over 88 % degradation in 5 min and 40 % mineralization within 60 min. While chlorinated and sulfate species enhance process efficiency, excessive electrolyte concentration should be avoided to prevent scaling and •OH scavenging. Phytotoxicity tests with Allium cepa revealed an unexpected reduction in toxicity in samples treated with NaCl, suggesting that Na2SO4 may be more phytotoxic under the tested conditions.

Integrative approach for monitoring the toxicity of effluents, surface water, and soil in the Cerrado biome

Monitoring the quality of water resources is essential to determine environmental impacts and seek sustainable management solutions. In this work, we demonstrated the toxicity of effluents and surface water of an important river in Central Brazil, the Meia Ponte River, using not just physicochemical parameters but also ecotoxicological bioindicators, such as Aliivibrio fischeri, Allium cepa, Lactuca sativa, and Salmonella typhimurium. To complement this data, we analyzed soil toxicity and quality along the river bank using A. fischeri and microbial enzymes. The data was associated with the land use pattern to discuss the environmental impacts caused by the land use and cover in the Cerrado biome. Although most physicochemical parameters were within the values allowed by Brazilian legislation, the A. fischeri bioluminescence inhibition assay indicated sample toxicity mainly in the non-treated effluent and near the river mouth (both water and soil samples). The germination indexes for L. sativa and A. cepa were reduced in most samples. Mutagenicity was observed in a surface water sample of one collection point during the dry season. The current data suggest the toxic potential of the surface water and soil along the Meia Ponte River and the non-treated effluent. The effluent treatment decreased the toxic potential of the samples but did not always eliminate the toxicity. The toxicity of the Meia Ponte River was most observed in urban and agricultural areas. Finally, our work demonstrated the need to monitor the environmental health of the Meia Ponte River basin, also used for public water supply.

Comprehensive approaches to managing emerging contaminants in wastewater: identification, sources, monitoring and remediation

Wastewater is a major source of contamination and must be treated before it is discharged into rivers and lakes. Water contaminated with emerging pollutants such as micropollutants, pharmaceuticals, endocrine disruptors (EDs), pesticides, synthetic dyes, toxins and hormones is of major concern due to its potential adverse effects. The accumulation of such pollutants can disbalance trophic levels and has negative ecological impacts and possible health risks. Monitoring and detecting these contaminants is essential for effective mitigation. Ongoing research on emerging contaminants drives the development of new analytical techniques and technologies for detection, monitoring and removal of such contaminants. As the demand for sustainable wastewater management increases, both conventional and advanced detection methods can be practised as treatment strategies. This approach enhances our capacity to detect and measure contaminants in environmental samples, leading to the development of more effective treatment methods. This review provides important insights into different classes of emerging contaminants, their sources as well as environmental and health risks associated with these pollutants. It also examines the major conventional and advanced technologies used to manage emerging contaminants.

Development of a new method using dispersive liquid-liquid microextraction with hydrophobic natural deep eutectic solvent for the analysis of multiclass emerging contaminants in surface water by liquid chromatography-mass spectrometry

A new analytical method was developed for the determination of 14 multiclass emerging organic contaminants in surface waters using LC-MS, and Dispersive Liquid-Liquid Microextraction (DLLME) for extraction. Different Natural Deep Eutectic Solvents (NADESs) composed of terpenes and organic acids were tested as extraction solvents and characterized by Fourier Transform Infrared Spectroscopy (FTIR), Hydrogen Nuclear Magnetic Resonance Spectroscopy (1H-NMR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), density, and viscosity, eliminating the need to use traditional chlorinated solvents. NADES produced with butyric acid and thymol showed the best results and was selected for application for the first time in the extraction of emerging organic contaminants of different classes in water samples. Vortex was used as the dispersion mode, eliminating the use of the dispersion solvent. Chromatographic conditions and sample preparation were optimized using multivariate experimental designs. The optimized chromatographic conditions included the column oven temperature, mobile phase modifiers, and stationary phase type. The optimized conditions for sample preparation included the extraction temperature and pH, salting out effect, and extraction solvent volume. The analytical performance was evaluated through repeatability and intermediate precision tests, with RSD values below 20%, and recoveries between 70 and 120%. The coefficient of determination was greater than 0.98 for all analytes. LOQs varied between 1.5 and 35 μg L-1. DLLME is a simple technique, it does not require expensive and specific equipment. Furthermore, replacing traditional chlorinated solvents with NADES makes the procedure more environmentally friendly. The method presented here can be applied to a wide range of analytes for the analysis of fresh, brackish, and salt waters. Up to the present moment, this is the first study using NADES based thymol and butyric acid for the determination of multiclass emerging contaminants in surface waters samples.

Hazardous fipronil insecticide effects on aquatic animals' health: Historical review and trends

Fipronil (FIP) is a broad-spectrum and highly efficient insecticide used against several arthropod pests, such as parasitic mites and insect pests affecting both animals and plants. Given its several benefits, FIP is widely used in the agricultural and veterinary medicine fields, but its indiscriminate use can have ecotoxic effects on non-target species. Thus, the current study aimed to summarise and critically analyse FIP's ecotoxicity in aquatic animals. Data referring to bibliometric parameters (publication year and geographical distribution), experimental conditions (field and laboratory, FIP type, animal class, species, habitat, and exposure conditions), and biomarkers (oxidative stress, DNA damage, neurotoxicity, and morphological changes) were summarised and critically analysed. Ecotoxicological studies were mainly conducted with insects, crustaceans, molluscs, and fish. Exposure to pure FIP or FIP-based commercial formulation can induce mortality and have sublethal effects on non-target organisms, such as increased reactive oxygen species (ROS), oxidative damage, genotoxicity (DNA damage), neurotoxicity, and morphological changes. The herein reviewed data have evidenced high median lethal FIP concentration (LC50) in vertebrates in comparison to invertebrates. The current findings confirmed that FIP can have several effects on aquatic organisms, besides suggesting potential ecotoxicological risks posed by this insecticide.

Removal efficiencies for 52 pesticides and pharmaceuticals from wastewater effluent by coupling solar heterogeneous photo-oxidation with TiO2 and infiltration in saturated soil column

Water resource management has become a hot button issue in recent decades. Countries facing water shortages as a result to climate change must adapt their water supply. The reuse of wastewater treatment plant effluents is becoming increasingly common around the world. However, the effluent quality must be improved before its reutilization to avoid contamination of the receiving environment. Pharmaceuticals and pesticides are particularly monitored because of their ubiquitous behaviours and limited removal by conventional wastewater treatment plants. The aim of this study was to combine heterogeneous photo-oxidation with TiO2 and soil infiltration to increase the elimination of contaminants of emerging concern (CECs). These advanced treatments were applied on an effluent coming from a WWTP equipped with a Ultrafor membrane bioreactor (sludge ages: 8-30 days, biomass concentration: 8-12 g.L-1, hydraulic retention: 6.7-8 h). The concentration of CECs was determined to evaluate the efficiency of coupling treatments. Photo-oxidation alone showed an impressive 98 % removal under spring conditions, while 66 % removal was observed under winter conditions. The differences observed for photo-oxidation were related to UV flux density, lower in winter than in spring (4.4 kJ.L-1 vs 6.6 kJ.L-1) and initial concentrations of the effluent higher in winter (50 μg.L-1 vs 26 μg.L-1). For both experiments, additional soil infiltration increased the global concentration of CECs removal to at least 89 % with equal removal contributions observed for some compounds. From the 52 CECs quantified in the WWTP effluent, at least 30 were totally removed by the advanced treatments while 4 compounds showed recalcitrant behaviours with global removal <60 %.

Integrated occurrence of contaminants of emerging concern, including microplastics, in urban and agricultural watersheds in the State of São Paulo, Brazil

Contaminants of emerging concern (CECs), including microplastics, have been the focus of many studies due to their environmental impact, affecting biota and human health. The diverse land uses and occupation of watersheds are important parameters driving the occurrence of these contaminants. CECs such as pesticides, drugs, hormones, and industrial-origin substances were analyzed in urban/industrial (Atibaia) and agricultural (Preto/Turvo) watersheds located in São Paulo state, Brazil. A total of 24 CECs were investigated, and, as a result, only 5 (caffeine, carbendazim, atrazine, ametrine and 2-hydroxytrazine) were responsible for 81.73 % of the statistical difference between watersheds contamination profile. The Atibaia watershed presented considerable concentrations of caffeine (ranging from 75 to 2025 ng L-1), while carbendazim (44 to 1144 ng L-1) and atrazine (3 to 266 ng L-1) presented highest levels in Preto/Turvo watershed. In all sampling points, the cumulative potential aquatic life risk assessed by the NORMAN database indicates some level of environmental concern associated to pesticides and caffeine (risk quotient >1). Microplastics had been analyzed in both watersheds, being the white/transparent fragments in size between 100 and 250 μm the most detected in this study. The estimated abundance in the Atibaia watershed ranged from 349 to 2898 items m-3 presenting some influence of pluviosity, while in Rio Preto/Turvo ranged from 169 to 6370 items m-3, being more abundant in the dam area without a clear influence of pluviosity. In both basins, polyethylene and polypropylene were the most detected polymers, probably due to the intense use of single-use plastics in urban areas. Possibly, due to the distinct physic-chemical properties of microplastics and organic CECs, no correlations were observed between their occurrence, which makes us conclude that they have different transport mechanism, behavior, and fate in the environment.

Experimental and modeling of potassium diclofenac uptake on activated carbon

The presence of pharmaceuticals in wastewater resulting from human activities has driven researchers to explore effective treatment methods such as adsorption using activated carbon (AC). While AC shows promise as an adsorbent, further studies are essential to comprehend its entire interaction with pharmaceuticals. This article investigates the adsorption of potassium diclofenac (PD) onto AC using experimental and modeling approaches. Batch adsorption studies coupled with Fourier transform infrared spectroscopy (FTIR) were employed to clarify the adsorption mechanism of PD on AC. Various kinetic and isotherm adsorption models were applied to analyze the adsorbent-adsorbate interaction. The kinetics were best described by Avrami's fractional order (AFO) nonlinear model. Also, the intraparticle diffusion (IP) model reveals a three-stage adsorption process. The experimental equilibrium data fitted well with the three-parameter nonlinear Liu model, indicating a maximum adsorption capacity (Qmax) of 88.45 mg g-1 and suggesting monolayer or multilayer adsorption. Thermodynamic analysis showed favorable adsorption (ΔG° < 0), with an enthalpy change (ΔH° = -30.85 kJ mol-1) characteristic of physisorption involving hydrogen bonds and π-π interactions. The adsorption mechanism was attributed to forming a double layer (adsorbate-adsorbent and adsorbate-adsorbate).

Emerging and legacy contaminants on the Brazilian southern coast (Santa Catarina): A multi-biomarker approach in oysters Crassostrea gasar (Adanson, 1757)

Coastal environments, such as those in the Santa Catarina State (SC, Brazil), are considered the primary receptors of anthropogenic pollutants. In this study, our objective was to evaluate the levels of emerging contaminants (ECs) and persistent organic pollutants (POPs) in indigenous Crassostrea gasar oysters from different regions of SC coast in the summer season (March 2022). Field collections were conducted in the São Francisco do Sul, Itajaí, Florianópolis and Laguna coastal zones. We analyzed the bioaccumulation levels of 75 compounds, including antibiotics (AB), endocrine disruptors (ED), non-steroidal anti-inflammatory drugs (NSAIDs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Furthermore, we assessed biomarker responses related to biotransformation, antioxidant defense, heat shock protection and oxidative damage in oysters' gills. Prevalence of ECs was observed in the central and southern regions, while the highest concentrations of POPs were detected in the central-northern regions of SC. Oysters exhibited an induction in biotransformation systems (cyp2au1 and cyp356a1, sult and GST activity) and antioxidant enzymes activities (SOD, CAT and GPx). Higher susceptibility to lipid peroxidation was observed in the animals from Florianópolis compared to other regions. Correlation analyses indicated possible associations between contaminants and environmental variables in the biomarker responses, serving as a warning related to climate change. Our results highlight the influence of anthropogenic activities on SC, serving as baseline of ECs and POPs levels in the coastal areas of Santa Catarina, indicating more critical zones for extensive monitoring, aiming to conserve coastal regions.

Biochemical responses in Pacific oysters Magallana gigas (Thunberg, 1793): Tools to evaluate the environmental quality of aquaculture areas

The discharge of sanitary sewage into the bays of the Florianópolis Metropolitan Area (Southern Brazil), has led to the contamination of oyster farms. Consequently, linear alkylbenzenes (LABs) were quantified in the sediment, and the biochemical responses in gills and digestive gland of oysters from six farms were assessed. Our findings revealed elevated levels of LABs in the sediment of the Imaruim and Serraria farms. Additionally, alterations were observed in the antioxidant enzymes: catalase, glutathione peroxidase and superoxide dismutase in both oyster tissue from the Serraria, Santo Antonio de Lisboa and Sambaqui farms. Furthermore, correlation analyses indicated strong and moderate associations between biochemical responses, organic contaminants, and certain physicochemical parameters. Consequently, our results demonstrated the activation of the antioxidant system in oysters, representing a protective response to the presence of sanitary sewage and other contaminants. Therefore, we propose the utilization of biochemical biomarkers for monitoring the environmental quality of farms.

Sonocatalytic degradation of Bisphenol A from aquatic matrices over Pd/CeO2 nanoparticles: Kinetics study, transformation products, and toxicity

In this work, different ratios of palladium - cerium oxide (Pd/CeO2) catalyst were synthesized and characterized, while their sonocatalytic activity was evaluated for the degradation of the xenobiotic Bisphenol A (BPA) from aqueous solutions. Sonocatalytic activity expressed as BPA decomposition exhibited a volcano-type behavior in relation to the Pd loading, and the 0.25Pd/CeO2 catalyst characterized by the maximum Pd dispersion and lower crystallite size demonstrated the higher activity. Using 500 mg/L of 0.25 % Pd/CeO2 increased the kinetic constant for BPA destruction by more than two times compared to sonolysis alone (20 kHz at 71 W/L). Meanwhile, the simultaneous use of ultrasound and a catalyst enhanced the efficiency by 50.1 % compared to the sum of the individual processes, resulting in 95 % BPA degradation in 60 min. The sonocatalytic degradation of BPA followed pseudo-first-order kinetics, and the apparent kinetic constant was increased with ultrasound power and catalyst loading, while the efficiency was decreased in bottled water and secondary effluent. From the experiments that were conducted using appropriate scavengers, it was revealed that the degradation mainly occurred on the bubble/liquid interface of the formed cavities, while the reactive species produced from the thermal or light excitation of the prepared semiconductor also participated in the reaction. Five first-stage and four late-stage transformation products were identified using UHPLC/TOF-MS, and a pathway for the sonocatalytic degradation of BPA was proposed. According to ECOSAR software prediction, most transformation by-products (TBPs) present lower ecotoxicity than the parent compound, although some remain toxic to the indicators chosen.

Enhancing disinfection and microcontaminant removal by coupling LED driven UVC and UVA/photo-Fenton processes in continuous flow reactors

For the first time, the sequential combination of UVC-LED (276 nm) and photo-Fenton/UVA-LED (376 nm) process has been assessed in continuous flow mode for wastewater reclamation according to the new European Regulation for reuse in agricultural irrigation (EU 2020/741). The results show that it is possible to obtain water quality class B (Escherichia coli ≤ 100 CFU/100 mL) by UVC-LED irradiation alone, operating the system with a hydraulic residence time (HRT) of 6.5 min and liquid depth of 5 cm in the case of secondary effluents with low Escherichia coli load (8.102-3.1.103 CFU/100 mL). As for high bacteria concentrations (1.2-4.2.104 CFU/100 mL), HRTs longer than 30 min are required. The bacterial load has not influenced decontamination, removing 18 ± 4 % of microcontaminants. Coupling the UVC (30-min HRT and 5.0 cm liquid depth) and the UVA/photo-Fenton (60-min and 15-cm liquid depth) systems allows 58 ± 4 % of real organic microcontaminants to be removed, in addition to achieving water quality class B.

Optimizing soil tetrabromobisphenol A remediation through iron-based activation of persulfate: A comparative analysis of homogeneous and heterogeneous systems

Tetrabromobisphenol A (TBBPA) that widely exists in soil and poses a potential threat to ecological environment urgently needs economically efficient remediation techniques. This study utilized both homogeneous Fe2⁺ solution and heterogeneous iron-based nanomaterials (chemically synthesized nano zero-valence iron (nZVI) and green-synthesized iron nanoparticles (G-Fe NPs)) to activate persulfate (PS) and assess their efficacy in degrading TBBPA in soil. The results demonstrate the superior performance of heterogeneous catalytic systems (WG-Fe NPs/PS (82.07%) and WnZVI/PS (78.32%)) over homogeneous catalytic system (WFe2+/PS (71.69%)), In addition, G-Fe NPs and nZVI effectively controlled the slow release of Fe2+. The optimization analysis using response surface methodology (RSM) reveal the remarkable significance of the experimental model based on the box-behnken design. RSM show that G-Fe NPs/PS exhibited optimal process parameters and predicted the maximum soil TBBPA degradation efficiency reaching 98.77%. The results of density functional theory calculations suggest that C-Br are the primary targets for electrophilic substitution reactions. Based on the f0 value and △G, the degradation pathway of TBBPA is inferred to involve a sequential debromination process, followed by the cleavage of intermediate carbon-carbon bonds and subsequent oxidation reactions. Hence, G-Fe NPs/PS not only facilitate waste resource utilization but also hold significant application potential.

Bibliometric analysis of Advanced Oxidation Processes studies with a focus on Life Cycle Assessment and Costs

Advanced oxidation processes (AOPs) are wastewater treatment technologies that stand out for their ability to degrade Contaminants of Emerging Concern (CECs). The literature has extensively investigated these removal processes for different aqueous matrices. Once technically mature, some of these systems have become accredited to be applied on a large scale, and therefore, their systemic performances in the environmental and cost spheres have also become essential requirements. This study proposed corroborating this trend, analyzing the available literature on the subject to verify how experts in the AOP area investigated this integration during 2015-2023. For this purpose, a sample of publications was treated by applying the Systematic Review (SR) methodology. This resulted in an extract of 83 studies that adopted life-cycle logic to estimate environmental impacts and process costs or evaluated them as complementary to the technical dimension of each treatment technology. This analysis found that both dimensions can be used for selecting or sizing AOPs at the design scale. However, the appropriate choice of the impact categories for the environmental assessment and establishing a methodology for cost analysis can make the approach still more effective. In addition, a staggering number of processes would broaden the reality and applicability of the estimates, and adopting multicriteria analysis methodologies could address essential aspects of decision-making processes during the design of the arrangements. By meeting the original purposes, the study broadened the requirements for designing AOPs and disseminating their use in mitigating the discharge of CECs.

Improvement of ferrioxalate assisted Fenton and photo-Fenton processes for paracetamol degradation by hydrogen peroxide dosage

This work aimed to investigate the impact of hydrogen peroxide (HP) punctual dosage on paracetamol (PCT) degradation, through Fenton and photo-Fenton processes under near-neutral pH conditions, using ferrioxalate and artificial sunlight. The assays were performed using a D-optimal experimental design, to statistically evaluate the influence of radiation (ON or OFF), HP concentration (94.5-756 mg L-1), and HP dosage (YES or NO), on PCT conversion. The optimal conditions determined from the study were: HP = 378 mg L-1, DOS = YES, and RAD = ON, achieving a predicted PCT conversion of 99.68% in 180 min. This result obtained from the model was very close to the experimental one (98.80%). It was verified that HP dosage positively influenced the iron catalytic cycle since higher Fe2+ concentrations were reached at shorter reaction times, accelerating not only PCT conversion but also its by-products hydroquinone and 1,4-benzoquinone, leading to better performances of Fenton and photo-Fenton reactions. Under optimal conditions and employing real water matrices (an artificial matrix with inorganic anions, a real groundwater sample, and a synthetic industrial wastewater), HP dosage demonstrated the ability to mitigate the negative effects caused by the content of different ions and other organic compounds and significantly improve HP consumption in challenging wastewater conditions.

Degradation of carbamazepine in surface water: performance of Pd-modified TiO2 and Ce-modified ZnO as photocatalysts

Carbamazepine is a widely used antiepileptic drug to control and treat a variety of disorders that is frequently detected in surface water, and in municipal and urban wastewater. This recalcitrant pollutant could be removed by alternative advanced oxidation technology such as heterogeneous photocatalysis. Ce-modified ZnO and Pd-modified TiO2 were synthesized by a microwave-assisted sol-gel method. According to the characterizations (Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy), a mixture of oxides was determined in both materials: CeO2/ZnO and PdO/TiO2. Photocatalytic degradation of carbamazepine in pure water under visible light (3 h) was assayed. The degradation percentage obtained with each catalyst was 80%, 53%, 20%, and 9% for ZnO, Ce-modified ZnO, TiO2, and Pd-modified TiO2, respectively. The leaching of Zn as a possible source of water contamination was tested, finding the lowest value for Ce-modified ZnO by adjusting the initial pH up to neutrality. Later, an environmentally relevant concentration of carbamazepine (228 µg L-1) was assayed, using local surface water (pH = 8.3). Despite the presence of other compounds in the real water matrix, after 5 h of photocatalysis, a 56% of degradation of the pharmaceutical and low leaching of Zn were achieved. The use of Ce-modified ZnO activated by visible light is a promising strategy for the abatement of pharmaceutical active compounds.

Comprehensive adsorption and spectroscopic studies on the interaction of magnetic biochar from black wattle sawdust with beta-blocker metoprolol

The rise of contaminants of emerging concern in water-resources due to human activities has driven research toward wastewater treatment, specifically adsorption. The utilization of woody biomass for biochar production in adsorption has shown promise due to its high availability. This study shows the preparation of magnetic biochars (MB) from waste black wattle sawdust, utilizing ZnCl2 and NiCl2 (proportions: 1:0.5:0.5 = MB-0.5 and 1:1:1 = MB-1) as activating and magnetic agents. Synthesized via microwave-assisted-pyrolysis, MB boasts a high surface area (up to 765 m2.g-1) and functional groups, enhancing metoprolol medicine adsorption. Nonlinear kinetic and isothermal models were tested; the Avrami fractional-order kinetic model and Liu's isothermal model provided the best fits for experimental data. Thermodynamics and spectroscopic studies revealed spontaneous and exothermic adsorption processes, with physisorption magnitude and dominance of hydrogen-bond and π-π-interactions. MB can be easily extracted from an aqueous medium using magnetic fields, while adsorption capacity could be regenerated through green solvent elution.

Occurrence of contaminants of emerging concern and their risks to the Pantanal Sul-Mato-Grossense aquatic biota, Brazil

The Aquidauana River is an important ecological corridor in the Pantanal biome. However, the growth of agricultural and urban areas along its banks has contributed to the deterioration of its water quality, consequently putting the aquatic biota at risk. Our objectives were to evaluate: 1) the composition of the landscape around six sampling sites located in the Aquidauana River middle section; and 2) the quality of its water by determining limnological parameters, concentrations of contaminants of emerging concern (CECs), and the risks to native aquatic biota. Water samples were collected in November 2020. We observed the conversion of native riparian vegetation to extensive pasture areas and anthropic occupation around the sampling sites. We observed that the chlorophyll and total ammoniacal nitrogen values were above the standards established by Brazilian legislation in all samples. Studies focused on the quantification of CECs in the Pantanal waters are scarce, and to the best of our knowledge, this is the first study that investigated the presence of pharmaceuticals in the Aquidauana River. All 30 C ECs analyzed were detected in at least one water sample. Eleven CECs were quantified with eight pesticides (atrazine, diuron, hexazinone, tebuthiuron, azoxystrobin, carbendazim, tebuconazole, and fipronil) and one atrazine degradation product (atrazine-2-hydroxy), caffeine, and bisphenol A. The concentrations of atrazine herbicide observed in the water samples pose risks for protecting aquatic biota (RQs >1). Therefore, the native biota of the Pantanal biome is vulnerable to several types of toxic contaminants observed in the water, which can cause the disappearance of native and endemic species in this region. Establishing a monitoring program, improving sanitation infrastructure, and intensifying good agricultural practices are essential for reducing and controlling the entry of CECs into the Aquidauana River and the Pantanal water system.

Photolysis of the novel meta-diamide insecticide broflanilide in solutions: Kinetics, degradation pathway, DFT calculation and ecotoxicity assessment

Broflanilide, as a novel meta-diamide insecticide, presents high bioactivity against agricultural pests. However, there was limited report regarding the photolysis fate of broflanilide. In this study, the photodegradation kinetics and influence factors of broflanilide, including different solvents, pH, iron, S₂O₈^2- and SO₃^2- were investigated under UV condition, and the reaction mechanism and transformation pathway were explored. The reaction rates (k) showed solvent-specificity in ultrapure water (0.015 min^-1), ethyl acetate (0.051 min^-1), methanol (0.084 min^-1) and acetonitrile (0.193 min^-1), correspondingly. The photolysis of broflanilide was slowest in the acid condition (pH = 4.0) compared with that in the neutral (pH = 7.0) and alkaline (pH = 9.0) conditions. The iron (Fe²⁺ and Fe³⁺) presented significant inhibition on the photodegradation due to the light shielding effect. Additionally, the UV/peroxydisulfate (S₂O₈^2-) and UV/sulfite (SO₃^2-) technologies could effectively accelerate the photodegradation of broflanilide, which has the potential for rapid treatment of pesticides in the aqueous environment. Six transformation products (TPs) were detected in water, peroxydisulfate and sulfite solutions, and the possible transformation pathways, including dehalogenation, cyclization, N-dealkylation, oxidation, reduction and hydrolysis, were proposed. Importantly, the reaction mechanism was explained through the analysis of molecular electrostatic potential and molecular orbitals. The predicted toxicity of the TPs indicated that several highly toxic TPs need to pay more attention in future risk assessments. This study provides a new perspective for evaluating the ecological fate and risks of pesticides.

Presence Of Non-Steroidal Anti-Inflammatories In Brazilian Semiarid Waters

Non-steroidal anti-inflammatory drugs (NSAIDs) act as antipyretics, analgesics and anti-inflammatories. Among them, diclofenac and ibuprofen are the most consumed drugs worldwide. During the COVID-19 pandemic, some NSAIDs, such as dipyrone and paracetamol, have been used to alleviate the symptoms of the disease, causing an increase in the concentrations of these drugs in water. However, due to the low concentration of these compounds in drinking water and groundwater, few studies have been carried out on the subject, especially in Brazil. Thus, this study aimed to evaluate the contamination of the surface water, groundwater, and water treated with diclofenac, dipyrone, ibuprofen, and paracetamol at 3 cities (Orocó, Santa Maria da Boa Vista and Petrolândia) in the Brazilian semiarid region, in addition to analyzing the removal of these drugs by conventional water treatment (coagulation, flocculation, sedimentation, filtration and disinfection) in stations to each city. All drugs analyzed were detected in surface and treated waters. In groundwater, only dipyrone was not found. Dipyrone was seen in surface water with a maximum concentration of 1858.02 μg.L^-1, followed by ibuprofen (785.28 μg.L^-1), diclofenac (759.06 μg.L^-1) and paracetamol (533.64 μg.L^-1). The high concentrations derive from the increased consumption of these substances during the COVID-19 pandemic. During the conventional water treatment, the maximum removal of diclofenac, dipyrone, ibuprofen and paracetamol was 22.42%; 3.00%; 32.74%; and 1.58%, respectively, which confirms the inefficiency of this treatment in removing drugs. The variation in removal rate of the analyzed drugs is due to the difference in the hydrophobicity of the compounds.

Acetaminophen degradation in aqueous solution by the UV-LED-EC/Cl2 process

In this study, electrochemically generated free chlorine (EC/Cl2) was activated by UV irradiation with a light emitting diode (LED) lamp at 275 nm to degrade acetaminophen (AAP, 2 μM) in aqueous solution. The potential at a RuO2-IrO2/Ti plate anode was set at 1.5 V vs. the Ag/AgCl electrode. Chlorine was in situ generated in the presence of Cl at the anode and then it was transformed into various active species such as OH and reactive chlorine species (RCS) under UV-LED irradiation. The degradation of AAP was investigated using batch tests, evaluating the influence of different experimental conditions such as NaCl concentration, phosphate buffer saline concentration, irradiation time and solution pH, keeping constant the UV-LED power and temperature. Results show that AAP could be completely degraded by the hybrid process with a high mineralization ratio (73%), and the degradation process followed a pseudo-first-order kinetics. The value of the Electric Energy per Order (EEO) = 1.272 kWh m3 order?, which is lower than the energy consumption of some other UV-based processes for AAP degradation. Adding 1 mM HCO3 ions slightly decreased the rate of AAP degradation. Luminescent bacteria experiment revealed that the acute toxicity of the reacted solution could be greatly reduced and the ecological risk was effectively abated. The scavenging assay shows that RCS plays a key role in the AAP degradation. The intermediate products were identified, and possible degradation routes were proposed. The system can advantageously replace conventional UV mercury lamp based ones in the degradation of microorganic pollutants.

Challenges on solar oxidation as post-treatment of municipal wastewater from UASB systems: Treatment efficiency, disinfection and toxicity

The application of solar photo-Fenton as post-treatment of municipal secondary effluents (MSE) in developing tropical countries is the main topic of this review. Alternative technologies such as stabilization ponds and upflow anaerobic sludge blanket (UASB) are vastly applied in these countries. However, data related to the application of solar photo-Fenton to improve the quality of effluents from UASB systems are scarce. This review gathered main achievements and limitations associated to the application of solar photo-Fenton at neutral pH and at pilot scale to analyze possible challenges associated to its application as post-treatment of MSE generated by alternative treatments. To this end, the literature review considered studies published in the last decade focusing on CECs removal, toxicity reduction and disinfection via solar photo-Fenton. Physicochemical characteristics of effluents originated after UASB systems alone and followed by a biological post-treatment show significant difference when compared with effluents from conventional activated sludge (CAS) systems. Results obtained for solar photo-Fenton as post-treatment of MSE in developed countries indicate that remaining organic matter and alkalinity present in UASB effluents may pose challenges to the performance of solar advanced oxidation processes (AOPs). This drawback could result in a more toxic effluent. The use of chelating agents such as Fe³⁺-EDDS to perform solar photo-Fenton at neutral pH was compared to the application of intermittent additions of Fe²⁺ and both of these strategies were reported as effective to remove CECs from MSE. The latter strategy may be of greater interest in developing countries due to costs associated to complexing agents. In addition, more studies are needed to confirm the efficiency of solar photo-Fenton on the disinfection of effluent from UASB systems to verify reuse possibilities. Finally, future research urges to evaluate the efficiency of solar photo-Fenton at natural pH for the treatment of effluents from UASB systems.

Occurrence of emerging organic contaminants and endocrine disruptors in different water compartments in Mexico - A review

This review compiles the studies (2007-2021) regarding the occurrence of emerging organic contaminants (EOCs) and endocrine disruptors (EDs) in wastewater, surface water and groundwater in Mexico. A total of 174 compounds were detected, including pharmaceuticals, hormones, plasticizers, personal care products, sweeteners, drugs, and pesticides considered as EDs. The levels of EOCs and EDs varied from ng/L to 140 mg/L, depending on the compound, location, and compartment. Raw wastewater was the most studied matrix, showing a greater abundance and number of detected compounds. Nevertheless, surface waters showed high concentrations of bisphenol-A, butylbenzil-phthalate, triclosan, pentachlorophenol, and the hormones estrone, 17 α-ethinylestradiol, and 17 β-estradiol, which exceeded the thresholds set by international guidelines. Concentrations of 17 α-ethinylestradiol and triclosan exceeding the above-mentioned limits were reported in groundwater. Cropland irrigation with raw wastewater was the principal activity introducing EOCs and EDs into groundwater. The groundwater abundance of EOCs was considerably lesser than that of wastewater, highlighting the attenuation capacity of soils/aquifers during wastewater infiltration. However, carbamazepine and N,N-diethyl-meta-toluamide showed higher concentrations in groundwater than those in wastewater, suggesting their accumulation/concentration in soils/pore-waters. Although the contamination of water resources represents one of the most environmental concerns in Mexico, this review brings to light the lack of studies on the occurrence of EOCs in Mexican waters, which is important for public health policies and for developing legislations that incorporates EOCs as priority contaminants in national water quality guidelines. Consequently, the development of legislations will support regulatory compliance for wastewater and drinking water, reducing the human exposure.

An Overview of the Impact of Pharmaceuticals on Aquatic Microbial Communities

Pharmaceuticals are present as pollutants in several ecosystems worldwide. Despite the reduced concentrations at which they are detected, their negative impact on natural biota constitutes a global concern. The consequences of pharmaceuticals' presence in water sources and food have been evaluated with a higher detail for human health. However, although most of the pharmaceuticals detected in the environment had not been designed to act against microorganisms, it is of utmost importance to understand their impact on the environmental native microbiota. Microbial communities can suffer serious consequences from the presence of pharmaceuticals as pollutants in the environment, which may directly impact public health and ecosystem equilibrium. Among this class of pollutants, the ones that have been studied in more detail are antibiotics. This work aims to provide an overview of the impacts of different pharmaceuticals on environmental biofilms, more specifically in biofilms from aquatic ecosystems and engineered water systems. The alterations caused in the biofilm function and characteristics, as well as bacteria antimicrobial tolerance and consequently the associated risks for public health, are also reviewed. Despite the information already available on this topic, the need for additional data urges the assessment of emerging pollutants on microbial communities and the potential public health impacts.