Presence, behaviour and removal of selected organic micropollutants through drinking water treatment.

This paper investigates the occurrence and removal of 60 organic micropollutants (OMPs) including pharmaceuticals, personal care products, pesticides and per- and polyfluoroalkyl substances in a drinking water treatment plant (DWTP) treating raw water from the Ebro River (NE Spain). The behaviour of the OMPs was evaluated in each treatment: pre-ozonation, flocculation-coagulation-decantation-sand filtration, post-ozonation and granular activated carbon filtration. Thirty-one of the sixty OMPs studied were detected in source water with individual median concentrations below 10 ng L-1 for all the compounds except for caffeine (64.1 ng L-1). The highest concentration peaks in the source water were found for caffeine (124.5 ng L-1), terbuthylazine (52.0 ng L-1), imidacloprid (30.2 ng L-1) and paracetamol (25.6 ng L-1). Of the 31 compounds detected in the source water, 17 were also detected in the finished drinking water. Of these 17 compounds, 10 were PFASs, which indicated that this group of compounds had not been effectively removed throughout the drinking water treatments. The overall removal efficiencies of OMPs in the DWTP ranged from -50.9% to 100%. The most efficient removal technologies were ozonation and granular activated carbon.

A liquid chromatography tandem mass spectrometry method for determining 18 per- and polyfluoroalkyl substances in source and treated drinking water.

Per- and polyfluoroalkyl substances (PFASs) have been determined in waters intended for human consumption, causing concern due to their potential toxic effects in humans and the environment. Drinking water is acknowledged to be one of the major routes of exposure to PFASs, which has led to the implementation of regulatory guidelines for PFASs in drinking water. In this study a fast, simple, sensitive and cost-effective method is developed for the determination of 18 PFASs in river and drinking water. The proposed method consists of directly injecting 900 µL of sample into a liquid chromatograph coupled to a triple quadrupole mass analyser, which involves minimal sample treatment as the sample only needs to be filtered. The method was validated in influent and effluent water from a drinking water treatment plant. Strong matrix effects were found for some of the target PFASs, and matrix-matched calibration curves were performed to enable accurate (87-114%) and precise (%RSD between 3 and 18%) quantification (n = 5, at 5 and 75 ng·L-1) with very good sensitivity (method quantitation limits between 0.1 and 2.0 ng·L-1). The method was applied to water samples from the influent and effluent of a drinking water treatment plant located in Catalonia (Spain), as well as in tap water and bottled water. The most abundant PFAS in all the types of water was PFBA, which represents 48%, 49%, 66% and 69% of total PFASs found in influent, effluent, tap and bottled water respectively. Relative mean abundances and the sum of mean concentrations in influent and effluent water suggests poor removal of PFASs during drinking water treatment. The concentrations of PFASs in bottled waters were generally lower than those in tap waters.

Liquid chromatography tandem mass spectrometry determination of 34 priority and emerging pollutants in water from the influent and effluent of a drinking water treatment plant.

This study evaluates the applicability of a method based on the direct injection of a large volume of water samples to identify and quantify 34 priority and emerging substances, most of them discussed in Directive 2013/39/EU on priority substances in the field of water policy, and Decision 2018/840/EU (Watch List). The method directly injects 500 µL of filtered water sample and so does not use a pre-concentration step. The method was satisfactorily validated for influent and effluent water from a drinking water treatment plant, at three concentrations (1, 10 and 100 ng L-1) with precision and accuracies in the range 1-17% and 71-122% respectively. Sensitivity was good with detection limits in the range 0.15-10 ng L-1 and complied with EU limits in all cases except for estrone, 17-ß-estradiol and 17-α-ethinylestradiol. For these hormones, an on-line solid phase extraction was developed and evaluated. The methods were applied to the analysis of water collected at the influent and effluent of a drinking water treatment plant and revealed the presence of 18 of the target compounds in the influent water and 8 in the effluent water. This showed that most the compounds had been efficiently removed by the processes of the drinking water treatment plant.

A simple, fast method for the analysis of 20 contaminants of emerging concern in river water using large-volume direct injection liquid chromatography-tandem mass spectrometry.

A fast and sensitive method for the determination of a structurally and physico-chemically diverse group of contaminants of emerging concern (CEC) based on large-volume direct injection liquid chromatography-tandem mass spectrometry was developed. The method can be used to determine 20 CECs belonging to different pollutant families (pharmaceuticals, personal care products, and pesticides) in river water at nanogram per liter. A single analytical run is required and the positive and negative ionization modes can be used simultaneously. Because of the large-volume injections of samples and the high sensitivity of the current mass spectrometers, the method has no need of a preconcentration step. The analytes are quantitated with matrix-matched calibration curves. The estimated limits of detection were in the range 0.1-5 ng L-1. The accuracy of the method was in the range 86-114%, and the precision, expressed as a relative standard deviation (RSD %), was below 18% for all the analytes (n = 5, at 5, 10, and 25 ng L-1). The method was applied to water samples taken from different points along the lower course of the Ebro River, Spain. A total of 12 out of the 20 target analytes were detected, and the ones at higher concentrations were caffeine and the pharmaceuticals paracetamol and ibuprofen (184.8 ng L-1, 63.3 ng L-1, and 23.3 ng L-1, respectively).