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.

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.

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 ±â€¯6% for 1,4-dioxane, 97 ±â€¯7% for 5,5-DMD and 100 ±â€¯0% for 2,5,5-TMD) than the upgraded conventional treatment line (ozonation followed by granular activated carbon filters) (-12 ±â€¯50%, 25 ±â€¯62% and 50 ±â€¯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.

Do cytostatic drugs reach drinking water? The case of mycophenolic acid.

Mycophenolic acid (MPA) has been identified as a new river contaminant according to its wide use and high predicted concentration. The aim of this study was to monitor the impact of MPA in a drinking water treatment plant (DWTP) that collects water downstream Llobregat River (NE Spain) in a highly densified urban area. During a one week survey MPA was recurrently detected in the DWTP intake (17-56.2 ng L(-1)). The presence of this compound in river water was associated to its widespread consumption (>2 tons in 2012 in Catalonia), high excretion rates and low degradability. The fate of MPA in waters at each treatment step of the DWTP was analyzed and complete removal was observed after pretreatment with chlorine dioxide. So far, MPA has not been described as water contaminant and its presence associated with its consumption in anticancer treatments is of relevance to highlight the importance of monitoring this compound.

Analysis of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues in chlorine-treated water by gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS).

A simple, selective and sensitive method for the analysis of the strong mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues (BMXs) in chlorine-treated water has been developed. The method is based on gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS), previous liquid-liquid extraction (LLE) of a smaller sample volume compared to other methods and on-line derivatization with a silylation reactive. GC-QqQ-MS/MS has been raised as an alternative easier to perform than gas chromatography coupled to high resolution mass spectrometry (GC-HRMS) for the analysis of MX and BMXs, and it allows to achieve low LODs (0.3 ng/L for MX and 0.4-0.9 ng/L for BMXs). This technique had not been previously described for the analysis of MX and BMXs. Quality parameters were calculated and real samples related to 3 drinking water treatment plants (DWTPs), tap water and both untreated and chlorinated groundwater were analyzed. Concentrations of 0.3-6.6 ng/L for MX and 1.0-7.3 ng/L for BMXs were detected. Results were discussed according to five of the main factors affecting MX and BMXs formation in chlorine-treated water (organic precursors, influence of bromide ions, evolution of MX and BMXs in the drinking water distribution system, groundwater chlorination and infiltration of water coming from chlorination processes in groundwater).