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• Electrokinetic soil remediation was assessed by high-resolution mass spectrometry. • Oxygen-rich molecules were transported to the anode by electromigration. • Large hydrogen-rich molecules were carried to the cathode by electroosmotic flow. • A highly automated suspect screening method for >3000 PFASs was applied. • The overlooked contaminant perfluoroheptanesulfonic acid was tentatively identified. Contamination of soils with organic pollutants is an increasing global problem, so novel soil remediation techniques are urgently needed. One such technique is electrokinetic remediation, in which an electric field is applied over the soil to extract contaminants. Previous evaluations of the technique have been limited to a few specific compounds. In this study, we integrated the latest advances in high-resolution mass spectrometry (HRMS) to identify molecular fingerprints, and used the results to improve the mechanistic understanding necessary for successful remediation. A laboratory-scale 0.38 mA cm−2 electrodialytic treatment was applied for 21 days to a contaminated soil from a firefighter training facility in Sweden. Non-target analysis allowed generic evaluation of changes in the soil organic fraction by tentatively determining the elemental composition of compounds present. The results showed that smaller oxygen-rich molecules were significantly transported to the anode by electromigration, while larger hydrogen-saturated molecules were transported to the cathode by electroosmotic flow. Wide suspect screening with >3000 per- and polyfluoroalkyl substances (PFASs) tentatively identified seven new PFASs in the test soil, including perfluoroheptanesulfonic acid (PFHpS), and PFASs with butoxy, ethoxy, ethanol, and ethylcyclohexanesulfonate functional groups. [ABSTRACT FROM AUTHOR]

To date, there is no analytical approach available that allows the full identification and characterization of highly complex disinfection by-product (DBP) mixtures. This study aimed at investigating the chemodiversity of drinking water halogenated DBPs using diverse analytical tools: measurement of adsorbable organic halogen (AOX) and mass spectrometry (MS)-based target and non-target analytical workflows. Water was sampled before and after chemical disinfection (chlorine or chloramine) at four drinking water treatment plants in Sweden. The target analysis had the highest sensitivity, although it could only partially explain the AOX formed in the disinfected waters. Non-target Fourier transform ion cyclotron resonance (FT-ICR) MS analysis indicated that only up to 19 Cl and/or Br-CHO formulae were common to all disinfected waters. Unexpectedly, a high diversity of halogenated DBPs (presumed halogenated polyphenolic and highly unsaturated compounds) was found in chloraminated surface water, comparable to that found in chlorinated surface water. Overall, up to 86 DBPs (including isobaric species) were tentatively identified using liquid chromatography (LC)-Orbitrap MS. Although further work is needed to confirm their identity and assess their relevance in terms of toxicity, they can be used to design suspect lists to improve the characterization of disinfected water halogenated mixtures., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Waste water treatment facilities are a major sources of organic micropollutants (MPs) in surface water. In this study, surface water samples were collected from seven sites along a river system in Uppsala, Sweden, during four seasons and evaluated based on the occurrence of MPs in the samples and bioactivity using in vitro bioassays. The sampling sites were differentially impacted by on-site sewage treatment facilities (OSSFs), small scale, and large scale waste water treatment plants (WWTPs). The bioassays used included activation of aryl hydrocarbon receptor (AhR), estrogen receptor (ER), nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB), nuclear factor erythroid 2-related factor 2 (Nrf2), and androgen receptor (AR). Occurrence of 80 MPs, were analyzed using liquid chromatography coupled to tandem mass spectrometry. Most water samples induced AhR activity, and all sampling sites showed a similar profile regarding this activity. With the exception of one water sample, we did not detect any NFkB, Nrf2 or AR activity of the water samples. The exception was a sample impacted by OSSFs, which showed an activity in multiple bioassays, but the activity could not be explained by the occurrence of target MPs. The occurrence of MPs showed a spatial trend, with the highest number and amount of MPs detected in the samples collected downstream of the WWTPs, where up to 47 MPs were detected in one single sample. A seasonal variation was observed with highest levels of MPs and highest AhR activities in samples collected in June and September 2015. However, neither the seasonal activity nor the on-site activity could be explained by the measured MPs, suggesting unknown contributory agents in the water.

This study demonstrates that regulatory databases combined with the latest advances in high resolution mass spectrometry (HRMS) can be efficiently used to prioritize and identify new, potentially hazardous pollutants being discharged into the aquatic environment. Of the approximately 23000 chemicals registered in the database of the National Swedish Product Register, 160 potential organic micropollutants were prioritized through quantitative knowledge of market availability, quantity used, extent of use on the market, and predicted compartment-specific environmental exposure during usage. Advanced liquid chromatography (LC)-HRMS-based suspect screening strategies were used to search for the selected compounds in 24 h composite samples collected from the effluent of three major wastewater treatment plants (WWTPs) in Sweden. In total, 36 tentative identifications were successfully achieved, mostly for substances not previously considered by environmental scientists. Of these substances, 23 were further confirmed with reference standards, showing the efficiency of combining a systematic prioritization strategy based on a regulatory database and a suspect-screening approach. These findings show that close collaboration between scientists and regulatory authorities is a promising way forward for enhancing identification rates of emerging pollutants and expanding knowledge on the occurrence of potentially hazardous substances in the environment.