Monitoring the complex occurrence of pesticides in the Llobregat basin, natural and drinking waters in Barcelona metropolitan area (Catalonia, NE Spain) by a validated multi-residue online analytical method

The European Directive 98/83/CE legislates the presence of pesticides in drinking water, but apart from a few compounds, nothing is said about which pesticides should be monitored. Nevertheless, water companies need to go beyond the accomplishment of the legislation and find out pesticide contamination in all sources of water in order to manage the hazard assessment, and to guarantee safe drinking water to all the population. The aim of this work was to develop an analytical multi-residue method for circa 100 compounds. The method analyses previously monitored compounds in Barcelona city and its metropolitan area, as well as many emerging pesticides and some transformation products. An on-line sample extraction (0.75 mL) coupled to fast UHPLC-MS/MS method was developed. Good linearity (r2 > 0.995, with less residuals than 15%), accuracies and precisions under 25%, and acceptable expanded uncertainties were obtained for most of the monitored compounds, according to ISO/IEC 17025, obtaining limits of quantification between 5 and 25 ng/L for all compounds. A monitoring campaign on natural and treated waters in the Barcelona metropolitan area was carried out during 2016–2017. Results showed that pesticide contamination at the low stretch of Llobregat River and in its aquifer is severe. The maximum concentrations were in the range of few μg/L for carbendazim, DEET, diuron and propiconazole, and in the range 0.1–0.5 μg/L for bentazone, imidacloprid, isoproturon, simazine, metazachlor, methomyl, terbutryn and tebuconazole. However, the efficiency of advanced treatments in the DWTPs involved in drinking water production in the Barcelona metropolitan area allows the complete removal of pesticides and a safe water production for consumers. The method shows a good analytical performance for most compounds with a fast sample preparation and analysis. In addition, it has updated the knowledge about the occurrence of pesticides in the Barcelona city area.We are grateful to Dr. Francesc Ventura for his critical revision of this work and to J. Martín-Alonso, M. Paraira, V. García-Tarriño, A. Cabeza and M. Ganzer for their knowledge and comments about the Llobregat River basin and drinking water distribution system. We are also grateful to all co-workers of the Analytical Organic Chemistry Department to deal with the daily work and for their time spent to move forward this study, as well as to the Sampling Department co-workers. This work has received funding from European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 727450. This presentation only reflects the authors' views and the Commission is not responsible for any use that may be made of the information it contains.Peer reviewe

Routine method for the analysis of microplastics in natural and drinking water by pyrolysis coupled to gas chromatography-mass spectrometry

The presence of microplastics (MPs) in water intended for human consumption represents a growing concern due to their ubiquity in the aquatic environments and the potential adverse effects on human health. In this context, validated and standardized analytical methods are required to minimize uncertainties associated with the determination of MPs in water, especially during the drinking water treatment process. In this study, a simple water sampling and extraction procedure and analysis using pyrolysis with gas chromatography coupled to mass spectrometry (Py-GC-MS) was developed to determine 7 types of polymers in water. Quality parameters associated with the method were evaluated, including limits of detection (MDL) and quantitation (MQL), linearity, precision, accuracy, and extended uncertainty. The developed methodology was validated by participating in the EUROQCHARM interlaboratory exercise, and the Z-scores were within the acceptable range for 4 of the 5 polymers tested. Finally, MPs were determined in river water, reclaimed water, and drinking water from the urban area of Barcelona and total concentrations ranged from 11.3 µg/L to 77.1 µg/L. The proposed methodology allows for simple (direct filtration of 100-500 mL of water with a 13 mm glass fiber filter), quantitative (µg/L), and rapid (with a total analysis time of 20 min per sample, including both pyrolysis and GC-MS) analysis of MPs in water intended for drinking.Support from the Ministry of Science and Innovation of Spain under the project PID2022–137766NB-I00 is acknowledged. Joan Dalmau-Soler acknowledges the support of Industrial Doctorates Plan of the University and Research Secretary of the Economy and Knowledge Department of the Generalitat de Catalunya. The authors also are grateful to the members of Organic Chemistry Department for their support and advice.Peer reviewe

Identification of 3-(trifluoromethyl)phenol as the malodorous compound in a pollution incident in the water supply in Catalonia (N.E. Spain)

A study of organic compounds that caused a serious taste and odor episode of water supply in two residential areas in Catalonia (N.E. Spain) was carried out. Sweet and paint/solvent odor were the main descriptors used by consumers. Some cases of sickness and nausea were also associated with drinking water consumption by the consumers. Closed-loop stripping analysis (CLSA) combined with sensory gas chromatography and gas chromatography mass spectrometry detection were used to study the problem. As a result, 3-(trifluoromethyl)phenol (CAS number 98-17-9) was for the first time identified as a responsible of an odor incident in drinking water. Concentration levels of this compound were up to 17,000 ng/L in groundwater and up to 600 ng/L in distributed water. Odor threshold in water for 3-(trifluoromethyl)phenol was determined as 13 ng/L (45 °C). © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.We are grateful to Dr. Auguste Bruchet for his explanations about past episodes in France involving fluoro-related compounds and to M.J. Domínguez-Cereijo for the details of the distribution system and sampling coordination. We are also grateful to all our colleagues of the Analytical Organic Chemistry Department for dealing with the daily work and spending time to move forward this study. We would also like to thank you I. Pérez and all the members and volunteers of the panel.Peer reviewe

Simultaneous analysis of 11 haloacetic acids by direct injection-liquid chromatography-electrospray ionization-triple quadrupole tandem mass spectrometry and high resolution mass spectrometry: occurrence and evolution in chlorine-treated water

A fast, simple, selective, and sensitive method for the analysis of 11 haloacetic acids (HAAs) in chlorine-treated water has been developed. The method is based on liquid chromatography-electrospray ionization-triple quadrupole tandem mass spectrometry (LC/ESI-QqQ-MS/MS) with direct injection of the aqueous sample. The main novelty of this method over the previously published procedures based on different techniques of mass spectrometry with direct injection is the combination of the simultaneous analysis of three types of HAAs (chlorinated, brominated, and iodinated) with its simplicity and low LODs (0.01–0.6 μg/L), avoiding the use of ion-pairing reagents for LC as well as the complexity and high cost of other techniques such as ion chromatography and capillary electrophoresis coupled to tandem mass spectrometry (IC-MS/MS and CE-MS/MS). The developed method was compared with another procedure carried out in our laboratory based on direct injection-liquid chromatography-electrospray ionization-high-resolution mass spectrometry with an Orbitrap analyzer (LC/ESI-Orbitrap-HRMS). The application of this technique to HAA analysis had not been previously described. LODs achieved by LC-HRMS (0.01–2 μg/L) were higher than the ones obtained by LC-MS/MS. Therefore, the LC/ESI-QqQ-MS/MS method was applied to the analysis of real samples. Quality parameters were calculated with satisfactory results and real samples related to three drinking water treatment plants (DWTPs), tap water, and the drinking water distribution system of Barcelona area (Catalonia, NE Spain) were analyzed. Furthermore, the evolution of HAA concentration along time in a DWTP-treated water sample was studied. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.This work has been financially supported by AGBAR in the framework of the AGBAR-CSIC R+D agreement on BControl of Organic Micropollutants in Water^ (grant number VATC 20140543).Peer reviewe

Dioxanes and dioxolanes in source waters: Occurrence, odor thresholds and behavior through upgraded conventional and advanced processes in a drinking water treatment plant

Over the last years, the human probable carcinogen 1,4-dioxane and alkyl-1,3-dioxanes and dioxolanes have been detected and identified as the cause of several pollution episodes in the Llobregat River (Catalonia, NE Spain) and its aquifer. It is an issue of major concern to study these compounds which are released to the environment by resin manufacturing plants' spills and wastewater discharges spread along rivers and reach drinking water treatment plants (DWTPs) in order to protect the environment and public health. In this study four seasonal sampling campaigns were carried out over a year to determine the removal efficiency of the dioxanes and dioxolanes at each step of a DWTP including ozonation, granular activated carbon filters, ultrafiltration and reverse osmosis step's treatments. Additionally, a weekly sampling monitoring of 1,4-dioxane and alkyl-1,3-dioxanes and dioxolanes in raw water, groundwater and finished water was performed at a DWTP over more than two years. Aqueous odor concentration thresholds (OTCs) were established by the three-alternative forced choice method (3-AFC). Following a previous published methodology, samples were analyzed and results showed that the advanced treatment (Ultrafiltration followed by reverse osmosis) line removes more efficiently 1,4-dioxane, alkyl dioxanes and dioxolanes (80 ± 6% for 1,4-dioxane, 97 ± 7% for 5,5-DMD and 100 ± 0% for 2,5,5-TMD) than the upgraded conventional treatment line (ozonation followed by granular activated carbon filters) (−12 ± 50%, 25 ± 62% and 50 ± 51% respectively), where some desorption processes were eventually observed. From the monitoring study, results suggest that the presence of 1,4-dioxane is not only due to spills, but also from other sources of contamination. Whereas dioxolanes almost completely disappeared in time, 1,4-dioxane's concentrations remained low and fluctuant. A background concentration of 1,4-dioxane in surface waters (∼1 μg/L) has been determined with a relevant concentration up to 11.6 μg/L of 1,4-dioxane in groundwater. The perception values for some of the studied compounds were extremely low (few ng/L only), which confirms the relevancy of this group of compounds as malodorous agents in waters. © 2019 Elsevier LtdAuthors are grateful to J. Martin and M. Minoves, M. Ganzer and S. Montes and the members of our Analytical Organic Chemistry Department for their technical support.Peer reviewe

Microplastics throughout a tap water supply network

The aim of the present study was to evaluate the presence of microplastics in drinking water along a large distribution water supply network. Tap water was collected in situ at sampling cabinets using an in-line sampling procedure that provided a representative sample with minimal risk of external contamination and avoided the transportation of large volumes to the laboratory. Microplastics > 50 μm were analysed via Fourier transform infrared spectroscopy (FTIR). Microplastics were detected in 38% of samples with a mean concentration of 0.01 microplastics per litre and polymers identified were polypropylene (PP), polyester (PES) and polyamide (PA). Detection of polytetrafluoroethylene (PTFE) and silicone particles were associated to the maintenance of cabinets. This study contributes to increase the knowledge regarding the presence and behaviour of microplastics throughout a large drinking water supply network providing water to 3 000 000 inhabitants. Results indicate that the pipes and the supply network not release microplastics into the drinking water.This work has been financed by the project ‘Microplastics in drinking water’ from Aigües de Barcelona and by the Ministry of Science and Innovation of Spain under the project PID2019-105732GB-C21. Joan Dalmau-Soler acknowledges the support of Industrial Doctorates Plan of the University and Research Secretary of the Economy and Knowledge Department of the Generalitat de Catalunya. The authors also are grateful to M. Paraira, J. Martin, M. Minoves and the members of Organic Chemistry Department for their support and advice.Peer reviewe

Synthesis and Gelling Abilities of Polyfunctional Cyclohexane-1,2-dicarboxylic Acid Bisamides: Influence of the Hydroxyl Groups

New enantiomerically pure C16-alkyl diamides derived from trihydroxy cyclohexane-1,2-dicarboxylic acid have been synthesized from (−)-shikimic acid. The hydroxyl groups in these compounds are free or, alternatively, they present full or partial protection. Their gelling abilities towards several solvents have been tested and rationalized by means of the combined use of Hansen solubility parameters, scanning electron microscopy (SEM), and circular dichroism (CD), as well as computational calculations. All the results allowed us to account for the capability of each type of organogelator to interact with different solvents and for the main mode of aggregation. Thus, compounds with fully protected hydroxyl groups are good organogelators for methanol and ethanol. In contrast, a related compound bearing three free hydroxyl groups is insoluble in water and polar solvents including alcohols but it is able to gelate some low-polarity solvents. This last behavior can be justified by strong hydrogen bonding between molecules of organogelator, which competes advantageously with polar solvent interactions. As an intermediate case, an organogelator with two free hydroxyl groups presents an ambivalent ability to gelate both apolar and polar solvents by means of two aggregation patterns. These involve hydrogen bonding interactions of the unprotected hydroxyl groups in apolar solvents and intermolecular interactions between amide groups in polar ones

Odor Events in Surface and Treated Water: The Case of 1,3-Dioxane Related Compounds

A study has been carried out to identify the origin of the odorous compounds at trace levels detected in surface waters and in Barcelona’s tap water (NE Spain) which caused consumer complaints. The malodorous compounds were 2,5,5-trimethyl-1,3-dioxane (TMD) and 2-ethyl-5,5-dimethyl-1,3-dioxane (2EDD) which impart a distinctive sickening or olive-oil odor to drinking water at low ng/L levels. Flavor profile analysis (FPA) or threshold odor number (TON) were used for organoleptic purposes. Levels up to 749 ng/L for TMD and 658 ng/L for 2EDD were measured at the entrance of the drinking water treatment plant. Three wastewater treatment plants (WWTPs) using industrial byproducts coming from resin manufacturing plants to promote codigestion were found to be the origin of the event. Corrective measures were applied, including the prohibition to use these byproducts for codigestion in the WWTPs involved. A similar event was already recorded in the same area 20 years ago