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Urbant dagvatten kan innehålla per- och polyfluoralkylämnen (PFAS). Den nuvarande kunskapen omförekomst och transport av PFAS i reningsanläggningar för urbant dagvatten är fortfarande mycketbegränsad. Den här studien utvärderar förekomst, ackumulering och fördelning av 35 PFAS och derasprekursorer i filtermaterial och försedimenteringssteg i tjugo biofilteranläggningar som varit i drift längreän 7 år. C5-14,16 perfluoralkylkarboxylsyror (PFCA), C4,8,10 perfluoralkansulfonsyror (PFSA), metylperfluoroktansulfonamidättiksyra (MeFOSAA, en känd PFSA-prekursor) och okända C6-8 PFCAprekursorer var de vanligast förekommande ackumulerade föreningarna. PFAS och deras prekursoreråterfanns i alla djup i liknande förekomster och koncentrationer. Trots att halterna var något högre i detövre filterlagret och minskande med djup var dessa skillnader i regel inte statistiskt signifikanta. Det fannsingen tydlig skillnad mellan fördelningen av kort- och långkedjiga PFAS, trots att långkedjiga ämnen(PFSAs>C5 och PFCAs>C7) förväntades ha mindre mobilitet på grund av deras högre hydrofobicitet. Deövre 5 cm av biofiltren innehöll ofta de högsta föroreningsnivåerna av PFAS och okända prekursorer,men de fanns också djupare ner i filtret. I motsats till exempelvis metaller och PAHer, räcker det sannolikt inte att endast byta ut det översta filterlagret och/eller sediment på toppen av filtret för att avlägsnamer komplexa och mobila föroreningar som PFAS., DRIZZLE, Dag&Nät

Dag&Nät

In this study, we show that pollutants of emerging concern are, by nature, prone to the emergence of epistemic uncertainty. We also show that the current uncertainty quantification methods used for pollutant modelling rely almost exclusively on parameter uncertainty, which is not adequate to tackle epistemic uncertainty affecting the model structure. We, therefore, suggest a paradigm shift in the current pollutant modelling approaches by adding a term explicitly accounting for epistemic uncertainties. In a proof-of-concept, we use this approach to investigate the impact of epistemic uncertainty in the fluctuation of pollutants during wet-weather discharge (input information) on the distribution of mass of pollutants (output distributions). We found that the range of variability negatively impacts the tail of output distributions. The fluctuation time, associated with high covariance between discharge and concentration, is a major driver for the output distributions. Adapting to different levels of epistemic uncertainty, our approach helps to identify critical unknown information in the fluctuation of pollutant's concentration. Such information can be used in a risk management context and to design smart monitoring campaigns., Validerad;2024;Nivå 2;2024-08-15 (hanlid);Full text license: CC BY 4.0

Bioretention systems are designed for quality treatment of stormwater. Particulate contaminants are commonly treated efficiently and accumulate mainly in the surface layer of the bioretention filter material. However, concerns exist that microplastic particles may not show equal accumulation behavior as other sediment particles. So far only two field and two laboratory studies are available on the fate of microplastics in few relatively newly built bioretention systems. Therefore, this study investigated the abundance and distribution of microplastics in nine 7–12 years old stormwater bioretention systems. It was found that microplastics generally accumulate on the surface of bioretention systems. Microplastic median particle concentrations decreased significantly from the surface layer (0–5 cm) of the filter material to the 10–15 cm depth layer from 448 to 136 particles/100 g, respectively. The distance to the inlet did not significantly affect the surface accumulation of microplastic particles, suggesting modest spatial variability in microplastics accumulation in older bioretention systems. Further, this study investigated the polymer composition in bioretention systems. It was shown that PP, EVA, PS and EPDM rubber are the most abundant polymer types in bioretention systems. Also, it was found that large percentages of microplastic particles are black particles (median percentage of black particles: 39%) which were found in 28 of the 33 investigated samples. This underlines the importance of including black particles in microplastic studies on stormwater, which has been overlooked in most previous studies., Validerad;2023;Nivå 2;2023-02-21 (joosat);Funder: Swedish Environmental Protection Agency (208-0182-18)Licens fulltext: CC BY License

Bioretention systems for urban drainage are one type of blue-green infrastructure that have gained more attention in recent decades. There are numerous design options for these systems, including various construction components, filter material mixtures, and plants. However, the research focus on the impacts of these many design options has mainly been technical, i.e., how different bioretention designs affect runoff pollution treatment and hydraulic control. Knowledge of the effects of various design elements on other sustainability criteria, such as economic, social, and environmental aspects, needs to be developed. This research aimed to evaluate and compare various design elements and bioretention types to gain a better understanding of the relative sustainability of various bioretention systems. This was accomplished by identifying relevant criteria and sub-criteria, covering social, economic, and technical-environmental indicators, in a multicriteria analysis. To evaluate the sustainability performance of various bioretention designs, 12 sub-criteria were allotted −100 to 100 points in a scoring process. The main finding was that while design features had a major impact on bioretention performance, no single design configuration excelled in all criteria. High scores in the social criteria were correlated with the use of trees and smaller volumes of pumice in the filter material mixture. In the economic criteria, extensive use of concrete and a complex mixture of filter material increased the costs. The system with a water-saturated zone and a variety of plant species outperformed the other systems in the technical-environmental criteria. The results can be utilized as a reference to assess design configurations that best satisfy specific needs for each unique bioretention implementation., Validerad;2023;Nivå 2;2023-05-03 (joosat);Licens fulltext: CC BY License

This study investigated how urban stormwater runoff, known to contain various chemical substances, alters pollutant concentrations in the receiving water bodies. Samples were collected under dry and wet weather conditions at 4 sampling stations along the Fyrisån, a river that passes along the city of Uppsala, Sweden. Samples were analyzed for 80 organic substances, 19 metals (total and dissolved phase), and conventional physicochemical parameters. 19 of 80 organic substances were qualified above the limit of quantification (LOQ) in at least one sampling event. The most detected substance family was poly-fluoroalkyl substances (PFAS). The concentrations of detected organic substances and metals increased in wet weather conditions. Organic substance and metal concentrations showed similar spatial variation with higher concentrations measured at sampling locations close to urbanized areas., Cette étude a examiné comment le ruissellement des eaux pluviales urbaines, connues pour contenir diverses substances chimiques, modifie les concentrations de polluants dans les masses d'eau réceptrices. Des échantillons ont été collectés dans des conditions de temps sec et humide dans 4 stations d'échantillonnage le long de la Fyrisån, une rivière qui passe le long de la ville d'Uppsala, en Suède. Les échantillons ont été analysés pour 80 substances organiques, 19 métaux (phase totale et dissoute), et des paramètres physico-chimiques conventionnels. 19 des 80 substances organiques ont été qualifiées au-dessus de la limite de quantification (LOQ) à au moins un des événements d'échantillonnage. La famille de substances la plus détectée était les substances polyfluoroalkyles (PFAS). Les concentrations des substances organiques et des métaux détectés ont augmenté par temps humide. Les concentrations de substances organiques et de métaux présentaient une variation spatiale similaire, les concentrations les plus élevées étant mesurées aux points d'échantillonnage proches des zones urbanisées.