Urban runoff is an important conveyor of microplastics (MPs) and tyre wear particles (TWP) to receiving waters. However, knowledge of contributions by surfaces within land use type/activities is currently limited. To address this knowledge gap, runoff samples were collected simultaneously during three rainfall events in October and November 2020 at three locations in Luleå, Sweden, with different urban surfaces (parking lot, road and roof). The occurrence of MPs (by number and estimated mass) and TWP (mass) were determined using μ-FTIR and Pyr-GC/MS, respectively. MPs and TWP were found at all sites in all events, with large variations between events and sites. The highest concentrations of MPs (number) and TWP were found in road runoff followed by parking lot runoff and roof runoff. The mass concentrations of MPs did not follow the same pattern and were generally highest at the parking lot, highlighting the importance of reporting data as both mass and particle numbers to derive a complete overview of MPs and TWP behaviour. Polypropylene, polyethylene, and polyester accounted, on average, for 99 % of MP polymers (by mass and number) at all sites with common sources, including traffic (vehicle wear and tear) and littering. MPs in the <75 μm fraction contributed >50 % of the total number of MPs in parking lot runoff, >58 % in roof runoff and > 90 % in road runoff.

Vanligen är vattenförekomster inom tätortsområden belastade av näringsämnen från flera källor, inklusivedagvatten. Näringsämnen som förs med dagvatten till recipienten kan därmed bidra till övergödning ochdärför efterfrågas ett bättre underlag för näringsämnen i dagvatten. I denna studie undersöktes förekomstav näringsämnen i dagvatten från tre olika urbana avrinningsområden – två industriparker och en parkering.Prover togs vid alla tre platser vid upp till sju olika tillfällen – tre regnhändelser, tre snösmältningshändelseroch ett regn-på-snö. I dagvattenledningarna i de båda industriområdena förekom kontinuerligtbasflöde som även det provtogs. Alla prover analyserades med avseende på totalfosfor och fosfatfosforsamt totalkväve och nitrit-, nitrat- och ammoniumkväve. Sett över alla prover (från alla tre platser och sjuprovtagningstillfällen) varierade totalkväve mellan 0,14-4,9 mg/l med ett medelvärde på 1,1 mg/l. Högstakoncentrationerna uppmättes i industriområde 1 (median: 1,0) jämfört med industriområde 2 (median:0,75 mg/l) och parkeringen (median: 0,6 mg/l). Trots de jämförelsevis låga flödena av basflöde i Industriområde1 och 2 så beräknades uppskattningsvis 46 % av fosforn och 72 % av kvävet från Ind 1 samt 9% av fosforn och 28 % av kvävet från Ind 2 släppas ut med basflödet vilket gör att även detta bör beaktasvid bedömning av näringsämnens belastning från dagvatten på recipienter. De lösta komponenternaav kväve (nitrit+nitrat+ammonium) utgjorde tillsammans 46 % av totalkväve. Totalfosforhalterna varierademellan 0,01-2,3 mg/l med medelvärde på 0,23 mg/l. Högsta koncentrationerna uppmättes även förtotalfosfor i industriområde 1 (median: 0,2 mg/l) jämfört med industriområde 2 (median: 0,1 mg/l) ochparkeringen (median: 0,08 mg/l). Fosfatfosfor utgjorde i genomsnitt 20 % av koncentrationen totalfosfor.Eftersom det saknas nationella riktlinjer kring näringsämnen i dagvattenutsläpp så jämfördes uppmättahalter med Göteborgs stads framtagna riktvärden. Dessa visade att riktvärdet för kväve (1,25 mg/l) överskredsför industriområdena, men inte för parkeringen. För fosfor överskred medianvärdena från alla treområden, inklusive basflödena, riktvärdet (0,05 mg/l). Enligt VISS databas förekom dock inga indikationerpå degradering av ekologisk status på grund av näringsämnen.

Urban runoff is recognised to contribute to the deterioration of surface water quality and previous research pointed out a need to focus on organic micropollutants. This study presents measurements of stormwater quality with respect to polycyclic aromatic hydrocarbons, oil, phthalates, alkylphenols, organotin compounds (OTC), polyfluoroalkyl substances (PFAS) and polychlorinated biphenyls (PCBs) from three Swedish catchments (two industrial parks and one parking lot). The results showed that all the studied groups of organic micropollutants except for PFAS and PCBs were present in the stormwater. The oil levels were similar in base flow compared to runoff, while other substances had higher concentrations during runoff events compared to base flow. Among the analysed phthalates, DEHP and DINP were those that were detected in concentrations above the analytical reporting limits, of which DINP was the most abundant, with a maximum concentration of 140 μg/L. Among the OTCs, monobutyltin was the most abundant, which was detected in all samples and present in the highest concentrations (up to 270 ng/L). Regarding the different types of runoff studied (rain, snowmelt and rain on snow) no clear differences could be identified by the available body of data.

Il est reconnu que le ruissellement urbain contribue à la détérioration de la qualité des eaux de surface et des recherches antérieures ont souligné la nécessité de se concentrer sur les micropolluants organiques. Cette étude présente des mesures de la qualité des eaux pluviales en ce qui concerne les hydrocarbures aromatiques polycycliques, les huiles, les phtalates, les alkylphénols, les composés organostanniques (OTC), les substances polyfluoroalkyles (PFAS) et les polychlorobiphényles (PCB) de trois bassins versants suédois (deux parcs industriels et un parking). Les résultats ont montré que tous les groupes de micropolluants organiques étudiés, à l'exception des PFAS et des PCB, étaient présents dans les eaux pluviales. Les niveaux d'huile étaient similaires dans le flux de base par rapport au ruissellement, tandis que d'autres substances avaient des concentrations plus élevées pendant les événements de ruissellement par rapport au flux de base. Parmi les phtalates analysés, le DEHP et le DINP sont ceux qui ont été détectés à des concentrations supérieures aux limites de déclaration analytique, le DINP étant le plus abondant. Parmi les OTCs, le monobutylétain était le plus abondant, il a été détecté dans tous les échantillons et présent dans les concentrations les plus élevées. En ce qui concerne les différents types de ruissellement étudiés (pluie, fonte des neiges et pluie sur la neige), aucune différence claire n'a pu être identifiée par l'ensemble des données disponibles.

Urban runoff is a diffuse source of pollution contributing to the poor ecological and chemical status of surface waters. Whilst the EU Priority Hazardous Substances Directive now identifies environmental quality standards for selected metals in relation to the bioavailable metal fraction the relationship between analytically determined metal size fractions transported by urban runoff and the often variably defined concept of bioavailability has not been thoroughly evaluated. This paper provides a review of the terminology used within urban runoff studies to characterise metal fractions and behaviour. Measured dissolved and truly dissolved (determined by ultrafiltration; <3000 molecular weight cutoff) Cu, Ni, and Zn concentrations are also compared to the bioavailable metal fraction (as predicted using Bio-met, a simplified biotic ligand model) in snowmelt and rainfall derived runoff samples from three urban catchments. The study shows that predicted bioavailable concentrations were significantly lower than truly dissolved concentrations for all metals and discusses current bioavailability modelling parameters in relation to rainfall and snowmelt runoff data sets. Statistical analysis of relationships between field and predicted bioavailable data sets indicate that the bioavailable fractions originate from both colloidal and truly dissolved fractions.

The size distribution of metals transported by urban runoff has implications for treatment type and design, predicting their mobility and evaluating their potential impact on receiving waters. There is an urgent need to better understand the distribution of metals between fractions, particularly those in the sub-dissolved fractions. As a contribution to addressing this need, this study characterises the size distribution of Cd, Cr, Cu, Ni, V and Zn using conventional and novel techniques. Data is presented as event mean concentrations (EMC) of a total of 18 rainfall and snowmelt events at three urban sites. For all studied metals in all events and at all sites, the contribution of the truly dissolved fraction made a greater contribution to the total concentrations than the colloidal fraction. Truly dissolved Cd and Zn concentrations contributed (on average) 26% and 28% respectively, of the total EMCs with truly dissolved Cu and Ni contributing (on average) 18%. In contrast, only 1% (V) and 3% (Cr) were identified in the truly dissolved fraction. The greatest contribution of truly dissolved Cd, Cu and Zn concentrations (relative to total concentrations) were reported during rainfall events. However, no seasonal differences were identified and differences between the sites regarding the EMCs distribution by fractions were not at a statistically significant level (p > 0.05) for any metal or event. The loads of truly dissolved and colloidal metals did not follow the patterns of particulate metal loads indicating particulates are not the main source of sub-dissolved metals. The data suggests that ultrafiltration as a treatment technique would not efficiently mitigate the risks posed by metals to receiving water ecologies.

Environment Quality Standards (EQS) stated by the EU Water Framework Directive complemented by national EQS support the work of risk assessments of bioavailable metals in freshwater environments. In this paper, dissolved and truly dissolved (operationally defined by ultrafiltration) Cu, Ni, Pb and Zn concentrations were used to predict and evaluate the bioavailable metal fraction (calculated using Bio-met) in snowmelt and rainfall runoff samples from two urban catchments. The results show that the bioavailable Cu and Zn concentrations exceed the EQSbioavailable and that there is a metal by metal variation regarding the fraction of truly dissolved metals that is also bioavailable. The results indicate that the truly dissolved metal fraction is not a suitable surrogate for the bioavailable fraction for these metals.

Les normes de qualité environnementale (NQE) énoncées dans la directive-cadre sur l'eau de l'UE, complétées par les NQE nationales, soutiennent les travaux d'évaluation des risques des métaux biodisponibles dans les environnements d'eau douce. Dans cet article, les concentrations de Cu, Ni, Pb et Zn dissous et réellement dissous (définis dans la pratique par ultrafiltration) ont été utilisées pour prévoir et évaluer la fraction de métal biodisponible (calculée avec Bio-met) dans les échantillons d'eaux de ruissellement issues de la fonte des neiges et de la pluie de deux bassins versants urbains. Les résultats montrent que les concentrations biodisponibles de Cu et de Zn dépassent les NQE biodisponibles et qu'il peut y avoir une variation de la fraction des métaux réellement dissous qui est également biodisponible, selon les métaux. Les résultats indiquent que la fraction de métal réellement dissous n'est pas un substitut approprié pour la fraction biodisponible de ces métaux.