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Aesthetic aspects of drinking water, such as Taste and Odor (T&O), have significant effects on consumer perceptions and acceptability. Solving unpleasant water T&O episodes in water supplies is challenging, since it requires expertise and know-how in diagnosis, evaluation of impacts and implementation of control measures. We present gaps, challenges and perspectives to advance water T&O science and technology, by identifying key areas in sensory and chemical analysis, risk assessment and water treatment, as articulated by WaterTOP (COST Action CA18225), an interdisciplinary European and international network of researchers, experts, and stakeholders.

Water radiolysis can serve as a useful tool to study the degradation of organic pollutants in water. Manipulation of the radiolytic system enables the selective production of reactive species (RS) with known yields. Our aim was to explore the effects of the radiolytically produced RS on commonly occuring water taste and odor compounds (T&O), 2-methylisoborneol (MIB) and geosmin (GSM). Observed degradation rate constants differ among experimental conditions/dominant RS and follow the order: HO•>H•>>eaq−>(O2−•/HO2•), ranging from 0.002 Gy−1 (O2−•/HO2•) to 0.083 Gy−1 (HO•) for MIB and from 0.006 Gy−1 (O2−•/HO2•) to 0.068 Gy−1 (HO•) for GSM. Degradation by HO• was very efficient, requiring 1.14 and 1.49 μmoles of HO• for each degraded μmole of MIB and GSM, respectively. The oxidative degradation of MIB by HO• proceeds with the production of carbonyl- and hydroxyl‑containing transformation products (TPs), leading to linear structures, while for GSM degradation proceeds with ring opening, followed by formation of carboxyl-groups. Fewer TPs are produced by HO2•, while degradation with H• led to numerous TPs, via dehydroxylation, dehydration and ring opening. Degradation with eaq−, yielded demethylated and rearranged TPs with formation of double bonds.

Microginins are the less common class of bioactive linear cyanobacterial peptides. Recently, an investigation for their presence in cyanobacteria from Greek freshwaters and strain cultures was carried out. The present dataset is related to the research article “New microginins from cyanobacteria of Greek freshwaters” [1]. Cyanobacterial biomass from bloom samples and cultured strains were extracted with aqueous methanol. Extracts were analysed by liquid chromatography coupled to hybrid triple quadrupole/linear ion trap mass spectrometer (LC-qTRAP MS/MS) in information dependent acquisition (IDA) mode. Enhanced ion product (EIP) mode was applied for the collection of ion fragmentation spectra. Identification of microginins was based on the characteristic fragment ions of the unique microginin amino acid 3-amino-2-hydroxy-decanoic acid (Ahda) and its modified forms. The analysis of fragmentation spectra revealed 51 microginin structures, including 36 new variants. This article provides the dataset of fragmentation mass spectra of the microginins detected in cyanobacteria from Greek freshwaters. As this class of cyanopeptides is produced by cyanobacteria from different geographical regions, the aim of this dataset is to enable the identification of microginins in future studies and therefore to contribute to a better evaluation of their presence in freshwater bodies worldwide.

The sensory quality of drinking water, and particularly its taste and odor (T&O) is a key determinant of consumer acceptability, as consumers evaluate water by their senses. Some of the conventional treatment processes to control compounds which impart unpleasant T&O have limitations because of their low efficiency and/or high costs. Therefore, there is a great need to develop an effective process for removing T&O compounds without secondary concerns. The primary objective of this study was to assess for the first time the effectiveness of spirulina-based carbon materials in removing geosmin (GSM) and 2-methylisoborneol (2-MIB) from water, two commonly occurring natural T&O compounds. The efficiency of the materials to remove environmentally relevant concentrations of GSM and 2-MIB (ng L -1 ) from ultrapure and raw water was investigated using a sensitive headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC/MS) method. Moreover, the genotoxic and cytotoxic effects of the spirulina-based materials were assessed for the first time to evaluate their safety and their potential in the treatment of water for human consumption. Based on the results, spirulina-based materials were found to be promising for drinking water treatment applications, as they did not exert geno-cytotoxic effects on human cells, while presenting high efficiency in removing GSM and 2-MIB from water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Cyanobacteria can reach high densities in eutrophic lakes, which may cause problems due to their potential toxin production. Several methods are in use to prevent, control or mitigate harmful cyanobacterial blooms. Treatment of blooms with low concentrations of hydrogen peroxide (H 2 O 2 ) is a promising emergency method. However, effects of H 2 O 2 on cyanobacteria, eukaryotic phytoplankton and zooplankton have mainly been studied in controlled cultures and mesocosm experiments, while much less is known about the effectiveness and potential side effects of H 2 O 2 treatments on entire lake ecosystems. In this study, we report on three different lakes in the Netherlands that were treated with average H 2 O 2 concentrations ranging from 2 to 5 mg L -1 to suppress cyanobacterial blooms. Effects on phytoplankton and zooplankton communities, on cyanotoxin concentrations, and on nutrient availability in the lakes were assessed. After every H 2 O 2 treatment, cyanobacteria drastically declined, sometimes by more than 99%, although blooms of Dolichospermum sp., Aphanizomenon sp., and Planktothrix rubescens were more strongly suppressed than a Planktothrix agardhii bloom. Eukaryotic phytoplankton were not significantly affected by the H 2 O 2 additions and had an initial advantage over cyanobacteria after the treatment, when ample nutrients and light were available. In all three lakes, a new cyanobacterial bloom developed within several weeks after the first H 2 O 2 treatment, and in two lakes a second H 2 O 2 treatment was therefore applied to again suppress the cyanobacterial population. Rotifers strongly declined after most H 2 O 2 treatments except when the H 2 O 2 concentration was ≤ 2 mg L -1 , whereas cladocerans were only mildly affected and copepods were least impacted by the added H 2 O 2 . In response to the treatments, the cyanotoxins microcystins and anabaenopeptins were released from the cells into the water column, but disappeared after a few days. We conclude that lake treatments with low concentrations of H 2 O 2 can be a successful tool to suppress harmful cyanobacterial blooms, but may negatively affect some of the zooplankton taxa in lakes. We advise pre-tests prior to the treatment of lakes to define optimal treatment concentrations that kill the majority of the cyanobacteria and to minimize potential side effects on non-target organisms. In some cases, the pre-tests may discourage treatment of the lake., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Harmful algal blooms events have been reported worldwide and during the last decades are occurred with increasing frequency and intensity due to the climate change and the high inputs of nutrients in freshwaters from anthropogenic activities. During blooms cyanobacteria release in water their toxic secondary metabolites, known as cyanotoxins, along with other bioactive metabolites. Due to the negative impacts of these compounds on aquatic ecosystems and public health, there is an urgent need to detect and identify known and unknown cyanobacterial metabolites in surface waters. In the frame of the present study, a method based on liquid chromatography - high resolution mass spectrometry (LC-HRMS) was developed to investigate the presence of cyanometabolites in bloom samples from Lake Karaoun, Lebanon. Data analysis was performed using Compound Discoverer software with related tools and databases in combination to the CyanoMetDB mass list for detection, identification and structural elucidation of the cyanobacterial metabolites. In the course of this study, 92 cyanometabolites were annotated including 51 cyanotoxins belonging to microcystins, 15 microginins, 10 aeruginosins, 6 cyclamides, 5 anabaenopeptins, a cyanopeptolin, the dipeptides radiosumin B and dehydroradiosumin, the planktoncyclin and a mycosporine-like amino acid. Out of them, 7 new cyanobacterial metabolites, the chlorinated MC-ClYR, [epoxyAdda 5 ]MC-YR, MC-LI, aeruginosin 638, aeruginosin 588, microginin 755C and microginin 727 were discovered. Moreover, the presence of anthropogenic contaminants was recorded indicating the pollution of the lake and emphasizing the need for assessment of the co-occurrence of cyanotoxins, other cyanobacterial metabolites and other compounds hazardous to the environment. Overall, results prove the suitability of the proposed approach for the detection of cyanobacterial metabolites in environmental samples but also highlight the necessity of spectral libraries for these compounds, considering the absence of their reference standards., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In the present study, the photocatalytic performance of exfoliated graphitic carbon nitride (g-C 3 N 4 ) catalysts, with enhanced properties and response in UV and visible light irradiation, was evaluated for the removal of selected contaminants i.e., diuron, bisphenol A and ethyl paraben. Commercial TiO 2 Degussa P25 was also used as a reference photocatalyst. The g-C 3 N 4 catalysts demonstrated good photocatalytic activity which in some cases is comparable to TiO 2 Degussa P25 leading to high removal percentages of the studied micropollutants under UV-A light irradiation. In contrast to TiO 2 Degussa P25, g-C 3 N 4 catalysts were also able to degrade the studied micropollutants under visible light irradiation. For all the studied g-C 3 N 4 catalysts under both UV-A and visible light irradiation, the overall degradation rate decreases in the order of bisphenol A > diuron > ethyl paraben. Among the studied g-C 3 N 4 , the chemically exfoliated catalyst (g-C 3 N 4 -CHEM) showed superior photocatalytic activity under UV-A light irradiation due to its enhanced characteristics, such as pore volume and specific surface area and ~ 82.0 % in 6 min, ~75.7 % in 15 min and ~ 96.3 % in 40 min removals were achieved for BPA, DIU and EP, respectively. Under visible light irradiation, the thermally exfoliated catalyst (g-C 3 N 4 -THERM) demonstrated the best photocatalytic performance and the degradation ranged from ~29.5 to 59.4 % after 120 min. EPR data revealed that the three g-C 3 N 4 semiconductors generate mainly O 2 •- , whereas TiO 2 Degussa P25 generates both HO • and O 2 •- , the latter only under UV-A light irradiation. Nevertheless, the indirect formation of HO • in the case of g-C 3 N 4 should also be considered. Hydroxylation, oxidation, dealkylation, dechlorination and ring opening were the main degradation pathways. The process proceeded without significant alterations in toxicity levels. Based on the results, heterogeneous photocatalysis using g-C 3 N 4 catalysts is a promising method for the removal of organic micropollutants without the formation of harmful transformation products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The present study was launched as a continuation of global efforts to tackle problems associated with two important aesthetic characteristics, taste and odor (T&O), of drinking water. The UV-A/Chlorine process, a promising advanced oxidation process (AOP), was evaluated for the first time for the removal of 2-isopropyl-3-methoxy pyrazine (IPMP), a widely reported compound in the literature that causes unpleasant taste and odor when present in water at or below the ng L -1 level. It was found that the studied process was efficient for the removal of IPMP in both ultrapure and drinking water. The initial chlorine dosage influenced significantly the degradation efficiency under initial neutral pH values. Degradation efficiency of IPMP was slightly inhibited by using drinking water as matrix. Scavenging experiments highlighted the significant role of various reactive species (e.g. HO, ClO, Cl, Cl 2 - ) generated during the process that have not been studied comprehensively until now. In addition, the significant role of HO was further verified by Electron paramagnetic resonance spectroscopy (EPR) experiments. Overall, the formation of diverse radicals during the UV-A/Chlorine treatment enhanced the degradation of IPMP, promoting mainly the formation of hydroxy, hydroperoxy and dealkylated derivatives. In contrast, chlorinated by-products were only identified in traces., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Cyanobacteria are photosynthetic microorganisms distributed globally in aquatic and terrestrial environments. They are also industrially cultivated to be used as dietary supplements, as they have a high nutritional value; however, they are also known to produce a wide range of toxic secondary metabolites, called cyanotoxins. BMAA (β-methylamino-l-alanine) and its most common structural isomers, DAB (2,4-diaminobutyric acid) and AEG (N-2-aminoethylglycine) produced by cyanobacteria, are non-proteinogenic amino acids that have been associated with neurodegenerative diseases. A possible route of exposure to those amino acids is through consumption of food supplements based on cyanobacteria. The review critically discusses existing reports regarding the occurrence of BMAA, DAB and AEG in cyanobacteria and cyanobacteria-based food supplements. It is shown that inconsistencies in reported results could be attributed to performance of different methods of extraction and analysis applied and in ambiguities regarding determination of soluble and bound fractions of the compounds. The critical aspect of this review aims to grow awareness of human intake of neurotoxic amino acids, while results presented in literature concerning dietary supplements aim to promote further research, quality control as well as development of guidelines for cyanotoxins in food products., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The cyanobacterium Cylindrospermopsis raciborskii represents a challenge for researchers and it is extensively studied for its toxicity and invasive behaviour, which is presumably enhanced by global warming. Biogeography studies indicate a tropical origin for this species, with Greece considered as the expansion route of C. raciborskii in Europe. The widening of its geographic distribution and the isolation of strains showing high optimum growth temperature underline its ecological heterogeneity, suggesting the existence of different ecotypes. The dominance of species like C. raciborskii along with their ecotoxicology and potential human risk related problems, render the establishment of a clear phylogeography model essential. In the context of the present study, the characterization of Cylindrospermopsis raciborskii TAU-MAC 1414 strain, isolated from Lake Karla, with respect to its phylogeography and toxic potential, is attempted. Our research provides new insights on the origin of C. raciborskii in the Mediterranean region; C. raciborskii expanded in Mediterranean from North America, whilst the rest of the European strains may originate from Asia and Australia. Microcystin synthetase genes, phylogenetic closely related with Microcystis strains, were also present in C. raciborskii TAU-MAC 1414. We were unable to unambiguously confirm the presence of MC-LR, using LC-MS/MS. Our results are shedding light on the expansion and distribution of C. raciborskii, whilst they pose further questions on the toxic capacity of this species., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Cyanobacterial and algal toxins comprise a large group of harmful metabolites, belonging to different chemical classes, with a variety of chemical structures, physicochemical properties and toxic activities. In this study, a fast, simple and sensitive analytical method was developed for the simultaneous determination of multi-class cyanobacterial and algal toxins in water. The target compounds were: Cylindrospermopsin, Anatoxin-a, Nodularin, 12 Microcystins ([D-Asp3]MC-RR, MC-RR, MC-YR, MC-HtyR, [D-Asp3]MC-LR, MC-LR, MC-HilR, MC-WR, MC-LA, MC-LY, MC-LW and MC-LF), Okadaic acid and Domoic acid. Analytes were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A dual Solid Phase Extraction (SPE) cartridge assembly was applied for the extraction of target compounds from water. Optimized SPE parameters included cartridge material, initial sample pH, sequence of the cartridges in the SPE assembly as well as composition and volume of the elution solvent. The method was validated, providing acceptable mean recoveries and reproducibility for most analytes. Limits of detection were at the ngL -1 level. The method was successfully applied in real lake water samples from Greece, where a wide range of Microcystins were detected for the first time, at concentrations ranging from 0.034 to 63μgL -1 ., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A method for the determination of the hepatotoxic cyanotoxins microcystins (MCs, i.e. MC-LR, MC-RR, MC-YR, MC-LA) and nodularin (NOD) in water was developed using liquid chromatography with electrospray ionization triple quadrupole mass spectrometry (LC-ESI-MS/MS) after solid phase extraction (SPE). New patterns of fragmentation of MC-LA were observed under the experimental conditions used. The method was fully validated to meet accreditation criteria. Mean recoveries at three concentration levels (0.006, 0.1 and 1 μg L(-1)) ranged between 70 and 114% with %RSD values generally below 20%. Detection limits were 2 ng L(-1) for all hepatotoxins. The method was applied to study the occurrence of MCs and NOD in Lake Marathonas, a water reservoir of Athens, over a period from July 2007 to December 2010. The protein phosphatase inhibition assay (PPIA) was additionally used for fast screening of samples. MC-YR, MC-LR and MC-RR were detected and found to vary seasonally with consistent peaks during early autumn, having maximum concentrations of 717, 451 and 174 ng L(-1), respectively. The results of this study constitute the first report on the presence, concentration levels and seasonal variations of MCs in Lake Marathonas. None of the target cyanotoxins were detected in treated drinking water samples during the period of the study., (Copyright © 2013. Published by Elsevier B.V.)

In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO(2) (N-TiO(2)) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO(2), Kronos and reference TiO(2) nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO(2) followed by N-TiO(2) with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO(2) nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO(2) for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO(2) displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO(2)(-), NO(3)(-) and NH(4)(+)) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light., (Copyright © 2011 Elsevier B.V. All rights reserved.)

A new method for the simultaneous determination of 1,4-dichlorobenzene (p-DCB), naphthalene and 1,2-dibromoethane (1,2-DBE) residues in honey has been developed. Analysis is carried out using gas chromatography-mass spectrometry (GC/MS) in selected ion monitoring mode (SIM), after extraction and preconcentration of target analytes by headspace solid-phase microextraction (HS-SPME), with a 100 microm film thickness polydimethylsiloxane (PDMS) fiber. Several parameters affecting the extension of the adsorption process (i.e., addition of salt, extraction time, extraction temperature) were studied. The optimal conditions for the determination of these analytes were established. The proposed HS-SPME method showed good sensitivity, without carryover between the samples. Linearity was studied from 5 to 2500 microg kg(-1) for p-DCB, 0.5 to 500 microg kg(-1) for naphthalene and 5 to 500 microg kg(-1) honey for 1,2-DBE with correlation coefficients (r(2)) ranging from 0.9901 to 0.9999. Precision was assessed and both intra and inter-day R.S.D.s (%) were below 6.3%. The detection limits were found to be 1, 0.1 and 2 microg kg(-1) honey for p-DCB, naphthalene and 1,2-DBE, respectively. The percentage recoveries that were evaluated with the proposed HS-SPME method and the standard addition calibration technique gave values among 72.8 and 104.3% for measurements in samples spiked with one target analyte or mixtures of the three. This method has been applied for the analysis of unknown honey samples. The results showed an excellent applicability of the proposed method for the determination of the target compounds in honey samples.

Introduction: The aim of this study was to quantitatively characterize the bisphenol-A (BPA) released from orthodontic adhesives after artificial accelerated aging., Methods: A chemically cured, no-mix adhesive and a visible light-cured adhesive were bonded to 40 stainless steel brackets divided in 2 groups of 20 brackets each. In total, 3 series of specimens were prepared for each adhesive-bracket group. All specimens were immersed in alcohol to induce accelerated aging. Samples of eluent removed from each group at 1 day and at 1, 3, and 5 weeks after aging were processed with high-pressure liquid chromatography; all assays were performed in triplicate, and the results were averaged., Results: No trace of BPA was identified for either adhesive across all time intervals, implying that, if present, the amount of BPA did not exceed the detection limit of the analytical technique (0.1 ppm or 0.1 microg/L)., Conclusions: BPA release from light-cured or chemically cured, no-mix adhesives did not reach the 0.1 ppm level. Estrogenicity assays are required to clarify the potential estrogenicity of adhesives, whereas formulation of benzoic ring-free, high molecular weight monomers might eliminate the concerns associated with the use of Bis-GMA.

Purpose: The purpose of this study was to estimate the degree of cure and monomer leaching of a light-cured and a chemically cured (no-mix) adhesive and to assess their biologic properties., Material: The degree of cure of adhesive specimens prepared with a procedure identical to the clinical bonding process was assessed by infrared spectroscopy. The adhesives were then immersed in normal saline solution for 2 months, and the residual monomer leached from the adhesives was quantitatively and qualitatively analyzed by liquid chromatography. The effect of the immersion media on human gingival fibroblasts' viability and proliferation was also evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and deoxyribonucleic acid (DNA) synthesis assays, respectively. The results were analyzed by analysis of variance and Tukey test (alpha = .05)., Results: No difference was found between the 2 adhesives with respect to their degree of cure and the amount of triethylene glycol dimethacrylate released; no diglycidyl dimethacrylate monomer was detected in the eluent. However, significant qualitative changes in the composition of the substances eluted from the 2 adhesives were observed., Conclusions: Whereas no cytotoxic effect was shown for either immersion media, a moderate reduction in the DNA synthesis was obtained by both adhesives, implying a minor cytostatic effect. Further research is required to assess the long-term biologic properties of adhesives, including potential estrogenic action.