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Sustainable urban drainage systems aim to promote the infiltration and the evapotranspiration (ET) processes rather than the runoff. In this study, the ET in 1 m3 pilot stormwater planters were studied from eight lysimeters monitored for three years in a dense urban environment in Paris (France). In each lysimeter, a piezometer, four weighing cells and a tipping bucket are used to measure respectively the water level in the internal water storage (IWS), the mass change of the whole lysimeter and the underdrain flow. Meteorological data, precipitation and water level are also collected respectively from the weather station, the rain gauge and the pan evaporimeter installed next to the lysimeters.Daily ET was calculated for each lysimeter based on a mass balance approach. The uncertainties related to the daily ET estimates were assessed at ± 0.42 to 0.58 mm depending to the lysimeter and according to the uncertainty propagation law. Results showed that for these lysimeters, with an impluvium equal to 4 times the vegetated surface, ET is the major term in water budget (57 to 90% of the cumulated water inputs) with maximum daily values reaching 8 mm/d. In addition, the observations showed that the major determinants of ET are the existence or not of an internal water storage (IWS) and the atmospheric factors (global radiation, air temperature and in a minor extent air humidity). The type of vegetation is a secondary determinant, with little difference between the herbaceous and the shrub configurations, maximum ET for spontaneous vegetation and minimal values when the vegetation was regularly removed. Shading of lysimeters by surroundings buildings is also an important factor and leads to lower values. Finally, ET with an IWS is higher than reference values tested (evaporimeter, FAO-56, and local Météo-France equations), except for regional Météo-France formula which overestimates ET of lysimeters and especially in summer. For future studies, it is expected to include some aspects in the experiments for explicitly addressing shading effects and vegetation evolution.

International audience; Road runoff (RR) is an important vector of micropollutants towards groundwater and soils, threatening the environment and ecosystems. Through combined chemical and biological approaches, the purpose of this study was to get insights on specific toxicants present in RR from two sites differing by their traffic intensity and their toxicological risk assessment. Non-target screening was performed by HRMS on RR dissolved phase. Ecotoxicological risk was evaluated in a zebrafish embryos model and on rat liver mitochondrial respiratory chain. Specific HRMS fingerprints were obtained for each site, reflecting their respective traffic intensities. Several micropollutants, including 1,3-diphenylguanidine (DPG) and benzotriazole (BZT) were identified in greater concentrations at the high-traffic site. The origin of DPG was confirmed by analyzing HRMS fingerprints from shredded tires. RR samples from each site, DPG and BZT were of relatively low toxicity (no mortality) to zebrafish embryos, but all generated distinct and marked stress responses in the light–dark transition test, while DPG/BZT mixes abolished this effect. The moderate-traffic RR and DPG inhibited mitochondrial complex I. Our study highlights (i) the unpredictability of pollutants cocktail effect and (ii) the importance of a multi-approaches strategy to characterize environmental matrices, essential for their management at the source and optimization of depollution devices.

Projected changes in temperature and precipitation in mid-latitude wet regions are expected to significantly affect forest ecosystems. We studied the physiological and shoot growth responses of Abies holophylla and Abies koreana seedlings to warming (3◦C above ambient temperature) and increased precipitation (irrigation with 40% of rainfall) treatments under open-field conditions. The physiological parameters, quantified by the net photosynthetic rate, transpiration rate, stomatal conductance, and total chlorophyll content, were monitored from July to October 2018. Shoot growth (i.e., root collar diameter and height) was assessed in August and December 2018. Irrespective of the treatments, the physiological parameters of both species decreased from July to August under warming treatment due to heat stress before recovering in September and October. Warming alone (W) and warming along with increased precipitation (W*P) decreased the physiological activities of both species in July, August, and September, with more pronounced effects on A. koreana compared with A. holophylla. Increased precipitation resulted in the increased chlorophyll content of both species in October. Shoot growth was not generally affected by the treatments, except for a subtle reduction in height under W*P for A. koreana. A. holophylla had consistently higher values for the physiological parameters and shoot growth than A. koreana. Our results indicate that the physiological activities of the Abies species could be seriously reduced under climate change, with a more severe impact on A. koreana. Among the two species, A. holophylla appears to be a more robust candidate for future forest planting. Validerad;2022;Nivå 2;2022-02-16 (sofila);Funder: Agence de l’Eau Seine Normandie; Office Français de la Biodiversité;For correction, see: Gasperi, J.; Le Roux, J.; Deshayes, S.; Ayrault, S.; Bordier, L.; Boudahmane, L.; Budzinski, H.; Caupos, E.; Caubrière, N.; Flanagan, K.; Guillon, M.; Huynh, N.; Labadie, P.; Meffray, L.; Neveu, P.; Partibane, C.; Paupardin, J.; Saad, M.; Varnede, L.; Gromaire, M.-C. Correction: Gasperi et al. Micropollutants in Urban Runoff from Traffic Areas: Target and Non-Target Screening on Four Contrasted Sites. Water 2022, 14, 2215. https://doi.org/10.3390/w14142215

Urban wet-weather discharges from combined sewer overflows (CSO) and stormwater outlets (SWO) are a potential pathway for micropollutants (trace contaminants) to surface waters, posing a threat to the environment and possible water reuse applications. Despite large efforts to monitor micropollutants in the last decade, the gained information is still limited and scattered. In a metastudy we performed a data-driven analysis of measurements collected at 77 sites (683 events, 297 detected micropollutants) over the last decade to investigate which micropollutants are most relevant in terms of 1) occurrence and 2) potential risk for the aquatic environment, 3) estimate the minimum number of data to be collected in monitoring studies to reliably obtain concentration estimates, and 4) provide recommendations for future monitoring campaigns. We highlight micropollutants to be prioritized due to their high occurrence and critical concentration levels compared to environmental quality standards. These top-listed micropollutants include contaminants from all chemical classes (pesticides, heavy metals, polycyclic aromatic hydrocarbons, personal care products, pharmaceuticals, and industrial and household chemicals). Analysis of over 30,000 event mean concentrations shows a large fraction of measurements (> 50%) were below the limit of quantification, stressing the need for reliable, standard monitoring procedures. High variability was observed among events and sites, with differences between micropollutant classes. The number of events required for a reliable estimate of site mean concentrations (error bandwidth of 1 around the “true" value) depends on the individual micropollutant. The median minimum number of events is 7 for CSO (2 to 31, 80%-interquantile) and 6 for SWO (1 to 25 events, 80%-interquantile). Our analysis indicates the minimum number of sites needed to assess global pollution levels and our data collection and analysis can be used to estimate the required number of sites for an urban catchment. Our data-driven analysis demonstrates how future wet-weather monitoring programs will be more effective if the consequences of high variability inherent in urban wet-weather discharges are considered., Water Research, 223, ISSN:0043-1354, ISSN:1879-2448

Les ouvrages de filtration végétalisés pour la gestion à la source des eaux pluviales, appelés à l’international des ouvrages de biofiltration, de biorétention ou vegetative filter strips, visent la maîtrise du flux polluant associé aux eaux pluviales urbaines. Ces ouvrages permettent le stockage, la fltration au travers d’un substrat planté et éventuellement l’infiltration de l’eau. L’efficacité épuratoire a été évaluée in situ pour deux systèmes de biofiltration, un accotement filtrant et une noue filtrante, pour un panel diversifié de polluants. Ce panel comprend des éléments traces métalliques (ETM) et des micropolluants organiques – des hydrocarbures aromatiques polycycliques (HAP), des alkylphénols, le bisphénol A (BPA), des phtalates – dans les phases totales et dissoutes. Les polluants essentiellement associés à la phase particulaire (Pb, Zn et HAP) étaient très bien retenus dans les ouvrages (abattements de concentration ›90%) pour la majorité des événements pluvieux. Cependant, une performance dégradée a été observée vis-à-vis des particules pendant la période hivernale, ce qui a été attribué à la taille plus fne des particules pendant cette période. Les abattements des concentrations dissoutes étaient rarement significatifs et tendaient à être bien plus faibles que ceux observés pour les matières en suspension (MES) et les polluants présents sous forme particulaire. De ce fait, des rétentions relativement faibles étaient observées pour les concentrations totales en polluants modérément particulaires, tels que le BPA, les alkylphénols et les phtalates. La rétention des ETM dissous semble avoir été limitée par leur association à la matière organique dissoute, alors que celle des micropolluants organiques dissous était limitée essentiellement par la contamination initiale du substrat filtrant ou par des émissions depuis les matériaux synthétiques de construction. À l’échelle annuelle, la noue filtrante dans sa configuration finale abattait entre 33 et 81% du flux polluant en fonction des polluants.

Le développement du contrôle à la source des eaux pluviales urbaines et, notamment, le recours croissant à des dispositifs d’infiltration suscitent des interrogations sur la capacité du sol à jouer le rôle de «filtre» vis-à-vis des polluants présents dans le ruissellement. Cette question a été abordée en couplant campagnes de terrain et approche de modélisation. Sur 11 dispositifs d’infiltration aux caractéristiques contrastées, le sol a été échantillonné en deux phases successives, conduisant à des cartographies de la contamination superficielle en métaux, puis à des profils verticaux de métaux et hydrocarbures aromatiques polycycliques (HAP), accompagnés de différentes variables explicatives. Les résultats ont démontré une bonne rétention des contaminants sur la plupart des sites d’étude, grâce à la combinaison de processus mécaniques (filtration) et physico-chimiques (adsorption). La distribution spatiale des métaux en surface, qui présente une structure caractéristique par rapport à la zone d’arrivée de l’eau, révèle le caractère non uniforme de l’infiltration lors des événements pluvieux courants. Dans la zone la plus polluée des ouvrages, métaux et HAP présentent un enrichissement significatif sur 10 à 40cm de profondeur. La contrepartie de cette rétention est une contamination qui, sur sept sites, excède localement les teneurs maximales admissibles –telles que définies par différentes normes internationales– dans le sol de zones résidentielles; toutefois, cela représente un volume de terres polluées relativement limité. L’approche de modélisation a permis de montrer que la durée de vie d’un dispositif d’infiltration pouvait être significativement améliorée en apportant un amendement organique à l’horizon superficiel, ce qui accroît la rétention de la pollution dissoute, ou en privilégiant une arrivée d’eau la plus répartie possible à la surface des ouvrages. La réduction des volumes d’eau de ruissellement en entrée d’ouvrage –par exemple, en déraccordant les eaux «propres» générées par le bassin versant– y participe également.

Recently, emphasis has been placed on finding a reliable estimation of soil water content. In this study, two capacitance sensors EC5 and 5TE (METER Group) were utilized. These sensors provide many benefits relative to other sensors in that they are cost-effective and very economical regarding energy use, operate at a high measurement frequency of 70 MHz, and are dedicated to measuring at a small volume because of their small size. This makes them suitable for the context of use in this research, which consists of multiple sustainable drainage systems SuDS. Several studies have evaluated these two types of sensor but not for urban soils with specific characteristics. In addition, results from the literature are divergent and the published calibration data are limited. Therefore, an in-depth investigation of their accuracy is assessed in this paper. At first, the literature&rsquo, s existing procedures and methods were examined. The sensor-to-sensor variability, as well as repeatability, were tested in soil and solutions. Additionally, a field calibration method was conducted to estimate the effects of soil texture on sensors readings. Two laboratory calibration methods having different principles were also applied, compared to each other and to the field calibration as well. Results revealed weak sensor-to-sensor variability (coefficient of variation up to 15% in soil) and also good repeatability (0.1%), for both sensors. A soil-specific calibration equation has improved the estimation of the volumetric water content. In case of soil having high field bulk density, the undisturbed soil calibration method described and proposed in this paper gives promising results. The latter method yields a volumetric water content (VWC) prediction accuracy of 0.025 m3∙m&minus, 3 on a sandy loam soil. This paper presents a large knowledge of capacitance sensors measurement technique as well as their calibration procedures and methods. Limitations of existing procedures have been identified and key elements for selecting the appropriate one are suggested. Derived calibration equations have also been provided for three urban soils with different particle size distribution, ranging from sandy loam to silt loam. Accurate monitoring of soil moisture content in urban soils is thus achievable.

International audience; Road runoff is contaminated by various micropollutants and may be treated using low impact development techniques, such as stormwater biofilters. Better understanding the processes, such as filtration, sorption and leaching, which affect pollutants in these systems is essential to reliably predicting treatment performance and optimizing system design. Field data from an in situ monitoring campaign, wherein dissolved and particulate concentrations of a wide range of micropollutants (trace metals, polycyclic aromatic hydrocarbons, bisphenol-A, alkylphenols and phthalates) were characterized in untreated road runoff and biofilter outlets for 19 rain events, are used to explore transport and retention processes. Although retention of the particulate phase of pollutants was generally quite effective, unusually high particle concentrations were observed at biofilter outlets for three winter events. Particle characterization in road runoff and outlet waters revealed that this degraded performance was due to poor filtration rather than particle erosion, which was attributed to the relative abundance of small (

This article describes a stochastic method to calculate the annual pollutant loads and its application over several years at the outlet of three catchments drained by separate storm sewers. A stochastic methodology using Monte Carlo simulations is proposed for assessing annual pollutant load, as well as the associated uncertainties, from a few event sampling campaigns and/or continuous turbidity measurements (representative of the total suspended solids concentration (TSS)). Indeed, in the latter case, the proposed method takes into account the correlation between pollutants and TSS. The developed method was applied to data acquired within the French research project "INOGEV" (innovations for a sustainable management of urban water) at the outlet of three urban catchments drained by separate storm sewers. Ten or so event sampling campaigns for a large range of pollutants (46 pollutants and 2 conventional water quality parameters: TSS and total organic carbon (TOC)) are combined with hundreds of rainfall events for which, at least one among three continuously monitored parameters (rainfall intensity, flow rate, and turbidity) is available. Results obtained for the three catchments show that the annual pollutant loads can be estimated with uncertainties ranging from 10 to 60%, and the added value of turbidity monitoring for lowering the uncertainty is demonstrated. A low inter-annual and inter-site variability of pollutant loads, for many of studied pollutants, is observed with respect to the estimated uncertainties, and can be explained mainly by annual precipitation.

International audience; Decentralized stormwater management generally involves the use of infiltration systems, the comportment of which is not always correctly understood. Incorrect assumptions about the hydrologic behavior of such systems can undermine their roles in both the quantitative and qualitative management of runoff, especially in systems designed to treat pollution at the source. Given the technical difficulty of directly measuring water fluxes in already existing systems, this paper discusses the utility of two indirect methods, applied to a real site made up of a vegetative filter strip followed by a biofiltration swale: the use of a hydrologic model and the characterization of soil pollution.The hydrologic model involves uncertainties due to its simplifying hypotheses and the variability of soil hydraulic conductivity measurements. Still, it can provide a rough estimation of the relative frequency of infiltration in different parts of the system. The cartography of contaminants, which shows that the majority of pollution is accumulated close to the roadside, indirectly provides time-integrated information as to the repartition of infiltration fluxes and the processes of sedimentation and filtration at the study site. The high spatial resolution of soil contamination data also provides evidence of heterogeneous surface runoff and infiltration flows.Despite the limits of each approach, both methods lead to the conclusion that the majority of runoff volumes - and as a consequence, the majority of pollutant loads - is infiltrated in the part of the system nearest to the system inlet: the vegetative filter strip. Therefore, the biofiltration swale does not fulfill its initially intended role of depolluting runoff water, as most pollutants do not reach it but rather are retained in the surface soil close to the roadside.; La mise en œuvre d'une gestion décentralisée des eaux pluviales implique généralement le recours à des systèmes d'infiltration, dont le fonctionnement n'est pas toujours correctement appréhendé. Une mauvaise évaluation de l'hydrologie peut s'avérer préjudiciable pour la gestion quantitative et qualitative du ruissellement, notamment dans des dispositifs conçus pour une maîtrise " à la source " des flux de polluants. Face aux difficultés associées à la mesure directe des flux d'eau et de polluants sur des ouvrages en place, on discute les apports de deux méthodes indirectes, appliquées à un site réel constitué d'une bande enherbée suivi d'un fossé filtrant: l'utilisation d'un modèle hydrologique et l'étude de la pollution du sol.Le modèle hydrologique présente des incertitudes dues à ses hypothèses simplificatrices, ainsi qu'à la variabilité des mesures de conductivité hydraulique. Il fournit toutefois un ordre de grandeur de la sollicitation relative des différentes parties de l'ouvrage. La cartographie des contaminants, qui montre que la majeure partie de la pollution s'accumule à proximité de la chaussée, renseigne indirectement sur la répartition " intégrée dans le temps " des flux d'infiltration et des processus de sédimentation/filtration sur le site d'étude. L'utilisation d'une résolution spatiale suffisamment fine permet de mettre en évidence des hétérogénéités dans l'infiltration et les écoulements superficiels.Malgré des limites propres à chaque approche, les deux méthodes mènent à la conclusion qu'une grande partie des volumes ruisselés - et, de facto, du flux polluant - est gérée par infiltration dans la bande enherbée, la partie de l'ouvrage à proximité immédiate de la zone d'arrivée de l'eau dans l'ouvrage. Ainsi, le fossé filtrant ne joue pas son rôle épuratoire de manière optimale, dans la mesure où les contaminants seraient retenus en bordure de chaussée dans le sol de surface.

International audience

International audience

Evaluating the performance of sustainable drainage systems (SuDS) in a field context presents a number of methodological problems. For this reason, as a part of three French research projects focused on this type of evaluation, Matriochkas, Micromegas and Roulepur, a working group on methodological harmonisation was established in order to facilitate the inter-comparison of results between the projects and propose a methodological guideline for practitioners carrying out such evaluations. The guideline proposes an approach where performance is evaluated with respect to a service function that the SuDS aims to achieve, itself identified from local issues. Its first section presents the various service functions which may be assigned to these devices. Next, performance indicators are defined for a selection of the identified service functions, common within the French context and studied as a part of the three projects. Three categories of indicators are identified: hydrologic indicators (relative to water flows), pollutant indicators and socio-technical indicators. Examples of instrumentation and of the application of the proposed indicators drawn from the experience of the three projects are also presented., L'évaluation in situ des performances des ouvrages de maîtrise à la source des eaux pluviales pose un grand nombre de questions d'ordre méthodologique. Ainsi, dans le cadre de trois projets de recherche français dédiés à ce type d'évaluation, Matriochkas, Micromegas et Roulépur, un groupe de travail sur l'harmonisation des méthodes a été constitué afin de faciliter l'inter-comparaison des résultats issus des projets, mais aussi de rédiger un guide méthodologique à destination des acteurs opérationnels pouvant être amenés à faire ce type d'étude. Ce guide propose une démarche où la performance est évaluée pour chaque fonction de service visée pour l'ouvrage, en réponse à des enjeux locaux. La première partie du guide détaille les fonctions de service pouvant être attendues de ce type d'ouvrage. Ensuite, des indicateurs de performance sont déclinés pour une sélection de fonctions de service couramment rencontrées dans le contexte français et qui ont pu être abordées au cours des projets. Ces indicateurs se regroupent en trois catégories : les indicateurs hydrologiques (relatifs aux flux d'eau), les indicateurs pollutifs (relatifs aux polluants) et les indicateurs sociotechniques. Le guide s'appuie sur des exemples issus des trois projets pour présenter des cas pratiques de dispositifs métrologiques et d'application des indicateurs proposés.

Novatech 2019, LYON, FRANCE, 01-/07/2019 - 05/07/2019; Evaluating the performance of sustainable drainage systems (SuDS) in a field context presents a number of methodological problems. For this reason, as a part of three French research projects focused on this type of evaluation, Matriochkas, Micromegas and Roulepur, a working group on methodological harmonisation was established in order to facilitate the inter-comparison of results between the projects and propose a methodological guideline for practitioners carrying out such evaluations. The guideline proposes an approach where performance is evaluated with respect to a service function that the SuDS aims to achieve, itself identified from local issues. Its first section presents the various service functions which may be assigned to these devices. Next, performance indicators are defined for a selection of the identified service functions, common within the French context and studied as a part of the three projects. Three categories of indicators are identified: hydrologic indicators (relative to water flows), pollutant indicators and socio-technical indicators. Examples of instrumentation and of the application of the proposed indicators drawn from the experience of the three projects are also presented.; L'évaluation in situ des performances des ouvrages de maîtrise à la source des eaux pluviales pose un grand nombre de questions d'ordre méthodologique. Ainsi, dans le cadre de trois projets de recherche français dédiés à ce type d'évaluation, Matriochkas, Micromegas et Roulépur, un groupe de travail sur l'harmonisation des méthodes a été constitué afin de faciliter l'inter-comparaison des résultats issus des projets, mais aussi de rédiger un guide méthodologique à destination des acteurs opérationnels pouvant être amenés à faire ce type d'étude. Ce guide propose une démarche où la performance est évaluée pour chaque fonction de service visée pour l'ouvrage, en réponse à des enjeux locaux. La première partie du guide détaille les fonctions de service pouvant être attendues de ce type d'ouvrage. Ensuite, des indicateurs de performance sont déclinés pour une sélection de fonctions de service couramment rencontrées dans le contexte français et qui ont pu être abordées au cours des projets. Ces indicateurs se regroupent en trois catégories: les indicateurs hydrologiques (relatifs aux flux d'eau), les indicateurs pollutifs (relatifs aux polluants) et les indicateurs sociotechniques. Le guide s'appuie sur des exemples issus des trois projets pour présenter des cas pratiques de dispositifs métrologiques et d'application des indicateurs proposés.

In order to determine the relative importance of a vegetative filter strip and a biofiltration swale in a treatment train for road runoff, US EPA SWMM was used to model infiltration and runoff from the filter strip. The model consists of a series of subcatchments representing the road, the filter strip and the side slopes of the swale. Simulations were carried out for different rain scenarios representing a variety of climatic conditions. In addition, a sensitivity analysis was conducted for the model's different parameters (soil characteristics and initial humidity, roughness, geometry…). This exercise showed that for the system studied, the majority of road runoff is managed by the filter strip rather than the biofiltration swale, an effect observed especially during periods of low-intensity rainfall. Additionally, it was observed that the combination of infiltration of road runoff in the filter strip and direct rainfall on the system leads to a significant and variable dilution of the runoff reaching the swale. This result has important implications for evaluating the treatment efficiency of the system., Afin de déterminer l'importance relative d'une bande enherbée dans un ouvrage combiné bande enherbée-fossé de biofiltration de traitement des eaux de ruissellement de voirie, le ruissellement et l'infiltration au niveau de la bande enherbée ont été modélisés avec US EPA SWMM. Le modèle consiste en une série de sous-bassins versants représentant la route, la bande enherbée et le talus du fossé. Des simulations ont été menées pour différents scenarios de pluies représentant une variété de conditions climatiques et en menant une analyse de sensibilité sur les différents paramètres du modèle (nature du sol, humidité initiale, rugosité, géométrie…). Cet exercice a montré que pour le système étudié, la grande majorité de l'eau est gérée par la bande enherbée et non pas par le fossé de biofiltration dans lequel peu d'eau arrive, notamment quand l'intensité de la pluie est faible. De plus, il a été observé que la combinaison de l'infiltration de l'eau de voirie sur la bande enherbée et de l'apport en précipitation directe sur l'ouvrage conduit à une dilution significative et variable de l'eau atteignant le fossé. Ces résultats ont des implications importantes pour l'évaluation de l'efficacité épuratoire du système.

International audience; Jérémie Sage, Elissar El Oreibi, Mohamed Saad, Marie-Christine Gromaire (2016). Modelling the temporal variability of zinc concentrations in zinc roof runoff – Experimental study and uncertainty analysis, Environmental Science and Pollution Research, pp. 1-15. The final publication is available at Springer via http://dx. ABSTRACT This study investigates the temporal variability of zinc concentrations from zinc roof runoff. The influence of rainfall characteristics and dry period duration is evaluated by combining laboratory experiment on small zinc sheets and in-situ measurements under real weather conditions from a 1.6 m² zinc panel. A reformulation of a commonly used conceptual runoff quality model is introduced and its ability to simulate the evolution of zinc concentrations is evaluated. A systematic and sharp decrease from initially high to relatively low and stable zinc concentrations after 0.5 to 2 millimetres of rainfall is observed for both experiments, suggesting that highly soluble corrosion products are removed at early stages of runoff. A moderate dependence between antecedent dry period duration and the magnitude of zinc concentrations at the beginning of a rain event is evidenced. Contrariwise, results indicate that concentrations are not significantly influenced by rainfall intensities. Simulated rainfall experiment nonetheless suggests that a slight effect of rainfall intensities may be expected after the initial decrease of concentrations. Finally, this study shows that relatively simple conceptual runoff quality models may be adopted to simulate the variability of zinc concentrations during a rain event and from a rain event to another.

Runoff infiltration in Sustainable Drainage Systems enables the interception of a part of urban contaminant fluxes owing to several processes. The soil's ability to retain dissolved pollutants is generally assessed via sorption isotherms obtained from batch studies; however, the experimental points are not always in the same range as runoff concentrations. The present work (i) explores the consequences of modelling runoff–soil interactions from out-of-range equilibrium concentrations and (ii) proposes an improved method to ensure that experimental points fall within the desired range. Uncertainty analysis demonstrates that for a non-linear isotherm, using an extrapolated relationship may introduce significant biases in the ensuing estimations. Therefore, the proposed method consists of anticipating the equilibrium state of batch tests to accurately set the experimental conditions and reach appropriate concentrations. It is successfully applied to the determination of the sorption properties of copper and zinc onto three soils with different electrolyte solutions, as well as those of bisphenol A and three alkylphenols onto one soil. The contrasting affinities between the studied species and the soil materials could be related to their intrinsic properties and the soils' pedological parameters, as well as the presence of salt or dissolved organic ligands which partially inhibited metal sorption.

International audience; The treatment efficiency of a vegetative filter strip and a biofiltration swale treating heavily loaded road runoff are evaluated. Concentrations measured in water drained from the two systems are compared to those in untreated road runoff collected from a reference catchment for a wide range of contaminants including organic carbon, nutrients (N and P), metallic trace elements, and organic micropollutants (polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), alkylphenols, bisphenol-A, phthalates), in both total and dissolved phases. Predominantly particulate pollutants, including Pb, Zn and PAH, were very efficiently removed (around 90%) for most events. However, poor particulate removal was observed during a winter period. Relatively few pollutants were significantly removed in the dissolved phase and observed concentration reductions tended to be lower than those of suspended solids and associated pollutants; as such, lower removals were observed for total concentrations of moderately particulate micropollutants, including bisphenol-A, alkylphenols and phthalates. In addition, some pollutants appear to be emitted from various biofilter components (filter media, drainage and lining materials), as low or negative concentration removals were observed during the first months of operation of the biofiltration swale.

Vegetated filter strips (VFS) are commonly employed as a best management practice to treat road runoff. In order to understand the long-term hydrologic behaviour of a road-side VFS, a coupled HYDRUS 2-D subsurface and 1D overland flow model was used. This model was validated over an 8 months period based on five soil moisture sensors readings. Results show good agreement between simulations and measurements for some sensors. Conversely, a discrepancy was identified for other sensors at particular periods. This outcome leads to a better understanding of the actual hydrological performance, such as a probable occurrence of preferential flow.

Bioretention systems are of great importance LID structures for acting in runoff control and pollutant removal. Modelling bioretention systems are defying because many process and functions are involved. There are many efforts in modelling such systems. In this paper, we reviewed literature in order to stablish what are the functions and process involved in the systems modeling and the most important gaps. Bioretention performance in controlling flood and in pollutant removal are of great variability. Process considered in models and their mathematical representation are very diverse. Clogging, evapotranspiration, chemical removal were the most defying process to be modelled.

Sustainable drainage systems (SuDS) have become a promising solution for increasing imperviousness by reducing water runoff volumes and flow rates, and improving water quality. However, the efficiency of these systems is dependent on soil hydraulic and physical properties, which in turn are spatially variable, however, this variability has been sparsely documented for urban areas, especially for road-side SuDS. In this study, the spatial variability of soil hydraulic properties, along with the uncertainty of these properties due to estimation methods, were investigated for three roadside SuDS in France (Paris region). Estimation methods were based on both in-situ infiltration tests and pedotransfer functions (PTFs). Results show high spatial variability in saturated hydraulic conductivity Ks (up to 160% coefficient of variation), which is dominant relative to uncertainties in PTFs predictions and those induced by experimental errors. Many specific factors might be responsible for this variability, especially in the urban context, such as construction techniques, CaCO3 precipitation, and vegetation development. In order to evaluate the effects of this variability on hydrological performance, a hydrological model of a bioretention cell was tested. Simulations revealed that peak flows and volumes are highly affected by the spatial variability of soil hydraulic properties, notably, vertical variability increases the overflow by 50%. The number of infiltration measurements required to evaluate a representative average Ks with an uncertainty of a factor of two or less was found to be four/eight, depending on the studied site. This study provides considerable insight into the spatial variability of soil hydraulic properties and its implications for hydrological performance of roadside SuDS, as it is based on a sound understanding of both theory and practice.

International audience; Cet ouvrage synthétise les connaissances scientifiques récentes sur les micropolluants dans les agglomérations urbaines. Il a pour ambition d’apporter des éléments de réponse aux interrogations opérationnelles des acteurs du domaine de l’eau et de l’assainissement et de favoriser ainsi une prise de conscience et des actions pour une meilleure gestion des micropolluants.Il s’appuie essentiellement sur les travaux des trois observatoires français en hydrologie urbaine (OPUR à Paris, OTHU à Lyon et ONEVU à Nantes), structurés autour de partenariats durables entre chercheurs et acteurs opérationnels. Depuis une vingtaine d’années, ces observatoires produisent des données et des connaissances sur les sources et les transferts des micropolluants et sur l’efficacité des différentes stratégies de gestion des eaux urbaines.Élaboré au sein du groupe « Micropolluants » de l’association ARCEAU-IdF avec le soutien et le financement de l’Agence française pour la biodiversité, cet ouvrage représente une étape importante dans le transfert des connaissances entre les chercheurs et les opérationnels. Il constitue un premier outil pour l’animation et la construction d’actions en faveur de la protection de l’environnement.

International audience; Roof maintenance practices often involve the application of biocide products to fight against moss, lichens and algae. The main component of these products is benzalkonium chloride, a mixture of alkyl benzyl dimethyl ammonium chlorides with mainly C12 and C14 alkyl chain lengths, which is toxic for the aquatic environment. This paper describes, on the basis of an in-situ pilot scale study, the evolution of roof runoff contamination over a one year period following the biocide treatment of roof frames. Results show a major contamination of roof runoff immediately after treatment (from 5 to 30 mg/L), followed by an exponential decrease. 175-375 mm of cumulated rainfall is needed before the runoff concentrations become less than EC50 values for fish (280 mu g/l). The residual concentration in the runoff water remains above 4 mu g/L even after 640 mm of rainfall. The level of benzalkonium ions leaching depends on the roofing material, with lower concentrations and total mass leached from ceramic tiles than from concrete tiles, and on the state of the tile (new or worn out). Mass balance calculations indicate that a large part of the mass of benzalkonium compounds applied to the tiles is lost, probably due to biodegradation processes. (C) 2015 Elsevier Ltd. All rights reserved.

Les flux de polluants associés aux eaux pluviales urbaines sont un facteur majeur de dégradation des milieux aquatiques superficiels dont la gestion est devenue un réel enjeu écologique au cours des dernières décennies. De nombreuses solutions techniques ont ainsi été développées afin de limiter la formation du ruissellement à l'amont des bassins versants urbains. Néanmoins, alors que la plupart des pays ou collectivités aspirent à la maîtrise de cette pollution, les réglementations ou prescriptions données aux opérationnels demeurent assez hétérogènes. L'objectif de cet article est donc, en se basant sur une synthèse bibliographique à l'international des pratiques de gestion des eaux pluviales, d'analyser les différents critères pouvant être donnés aux aménageurs en considérant à la fois leur pertinence pour la maîtrise des flux de polluants et les implications de leur définition en termes de choix ou de dimensionnement des techniques alternatives. Alors que les critères hydrologiques volumiques, directement rattachés au fonctionnement des techniques alternatives, semblent être préférables pour une maîtrise à la source des polluants ruisselés, cette étude indique que l'adoption de solutions de gestion à moindre impact des eaux pluviales demeure probablement très dépendante des outils de sélection ou de conception des techniques alternatives mis à disposition des aménageurs.

Alkylphenol (AP) and bisphenol A (BPA) contamination of urban runoff has already been established. Potential sources of these contaminants in runoff are endogenous to the urban watershed and are mainly related to traffic and leaching from construction materials. This article summarizes the results of experimental work carried out on a selection of building materials, automotive materials, and consumables, which can be in contact with rain, to assess their potential emission of alkylphenols, alkylphenol ethoxylates, and bisphenol A into runoff. 36 samples of materials, new and used, across 7 major families of building materials (PVC, concrete, polycarbonate, SBS-modified bitumen, drainage materials) and automotive materials (body, tires) were subjected to leaching tests with methanol and then, for a selection of them, with water. Automotive fluids were also directly analyzed. The results demonstrate the ubiquitous presence of APs and BPA in urban materials and their extractable character with water. The compounds with the strongest emission rates were bisphenol A and nonylphenol. The most important BPA emissions into water (10 to 300 ng/g) were measured for polycarbonate, tires, some car bodies, and PVC. Nonylphenol was leached in large quantities (1 to 10 ng/g) from PVC, some concretes, SBS-modified bitumen, and body samples. The tires were the only materials having a strong emission in octylphenol (1 to 10 ng/g). The analysis of automotive fluids confirmed the presence of BPA (0.3 to 5.5 g/L) and nonylphenol (2.3 to 2.9 mg/L) in brake fluids, while APs and BPA were found at trace levels in coolants and windscreen washer. Graphical abstract ᅟ.

International audience; Among the processes governing contaminant retention in soil-based Sustainable Urban Drainage Systems (SUDS), quantifying the relative contribution of particle settling and filtration requires a tracer of runoff-generated solids. Since zirconium (Zr) is a widely used geochemical invariant in pedological approaches, with few anthropogenic sources, the present investigation aims to assess whether its use may be extended to sediment identification in SUDS. High-resolution horizontal and vertical soil sampling was carried out in 11 infiltration systems, as well as in road-deposited sediment. Following elemental analysis via X-ray fluorescence spectrometry, the spatial distribution of both Zr and urban-derived metals could be determined. Zr content in sediment was found to be fairly stable and significantly lower than in soil. In most devices, Zr and metals exhibited "mirror" trends, both horizontally and vertically, i.e. a deficit of Zr could be observed in the most contaminated area. This indicated a "dilution-like" mixture of soil and sediment, the fraction of which could be calculated and appraised spatially. The vertical profiles proved the occurrence of bed filtration over 5 to 15 cm, and enabled the calibration of a simple filtration model. The uncertainties associated with the determined filter coefficient were found to be comparable to the other experimental methods – with the additional improvement that the present approach does not require water sampling.

Les JDHU sont organisées depuis 2004, tous les deux ans, par les équipes de recherche français en hydrologie urbaine et en assainissement, avec le parrainage des associations professionnelles de l’eau la SHF et l’ASTEE.L’objectif de ces journées conviviales est de permettre à des doctorants francophones de présenter leurs travaux de thèse, et ainsi de mieux se connaître et échanger. Des chercheurs et des acteurs opérationnels sont aussi présents et accompagnent les échanges.

International audience; Depuis quelques décennies, on observe le développement de systèmes végétalisés conçus pour stocker, filtrer et parfois infiltrer à la source les eaux de ruissellement urbaines. Dans le monde anglophone de nombreux guides ont été publiés afin d'encadrer la conception et la maintenance de ce type d'ouvrage, qualifiés de bioretention. Ces guides, issus de retour d'expérience dans ces pays, proposent des préconisations relatives à l'emplacement des ouvrages, leurs modes de vidange, les caractéristiques des couches du filtre, les critères et méthodes de dimensionnement, le choix des végétaux et l'entretien des ouvrages. Comme ces techniques sont encore relativement peu diffusées en France et ne font pas encore l'objet de tels guides, cet article a pour vocation de dresser une synthèse d'une sélection de ces guides. Abstract: Over the past few decades, vegetated systems designed for the on-site storage, filtration and sometimes infiltration of urban runoff have been developed and become increasingly popular. Across the English-speaking world, one can find a great many guides providing detailed information as to the design and maintenance of this type of system, referred to as bioretention. These guides, which present advice as to where to locate these systems, how to drain them, the characteristics of the filter media, sizing methods, plant choice and system maintenance, contain a wealth of valuable information and feedback from the experience in these countries. As this technique is relatively new in France and no such detailed guidelines yet exist, this article synthesizes the information from a selection of these guides. 2

International audience; The increasing use of infiltration-based systems for stormwater management questions the soil's ability to act as a long-term filter for runoff contaminants, and brings about operational matters regarding the most effective maintenance practices to enhance contaminant retention in SUDS. This paper reports the vertical extent of metal and PAH contamination in the soil of seven source-control devices in operation for more than 10 years, assessed via a two-step sampling strategy to optimize the representativeness of the contamination profiles. Metal distribution was typically characterized by a significant surface buildup, followed by a decrease in concentrations with increasing depth, usually coming close to the background values. PAH were more heterogeneously distributed with depth, but their accumulation was globally restricted to the upper 10-40 cm. This indicates an interesting potential for pollution interception by the upper horizons of soil, but does not necessarily prevent from downward fluxes, even while measuring low surface contents, as deeper strata may have lesser retention capacities. Specific amendments of the surface soil may help prevent this problem. Surface soil renewal – which would be necessary over 2.5 to 30 cm in four sites, according to the "strictest" standards for soil remediation – may regenerate the soil's sorption potential, but such a practice could disrupt the interactions with the local ecosystem, so this should be carried out exceptionally and not as a preventive measure.

International audience; Sewage systems are a vital part of the urban infrastructure in most cities. They provide drainage, which protects public health, prevents the flooding of property and protects the water environment around urban areas. On some occasions sewers will overflow into the water environment during heavy rain potentially causing unacceptable impacts from releases of untreated sewage into the environment. In typical Life Cycle Assessment (LCA) studies of urban wastewater systems (UWS), average dry-weather conditions are modelled while wet-weather flows from UWS, presenting a high temporal variability, are not currently accounted for. In this context, the loads from several storm events could be important contributors to the impact categories freshwater eutrophication and ecotoxicity. In this study we investigated the contributions of these wet-weather-induced discharges relative to average dry-weather conditions in the life cycle inventory for UWS. In collaboration with the Paris public sanitation service (SIAAP) and Observatory of Urban Pollutants (OPUR) program researchers, this work aimed at identifying and comparing contributing flows from the UWS in the Paris area by a selection of routine wastewater parameters and priority pollutants. This collected data is organized according to archetypal weather days during a reference year. Then, for each archetypal weather day and its associated flows to the receiving river waters (Seine), the parameters of pollutant loads (statistical distribution of concentrations and volumes) were determined. The resulting inventory flows (i.e. the potential loads from the UWS) were used as LCA input data to assess the associated impacts. This allowed investigating the relative importance of episodic wet-weather versus “continuous” dry-weather loads with a probabilistic approach to account for pollutant variability within the urban flows. The analysis at the scale of one year showed that storm events are significant contributors to the impacts of freshwater eutrophication and ecotoxicity compared to those arising from treated effluents. At the rain event scale the wet-weather contributions to these impacts are even more significant, accounting for example for up to 88% of the total impact on freshwater ecotoxicity. This also allowed investigating and discussing the ecotoxicity contribution of each class of pollutants among the broad range of inventoried substances. Finally, with such significant contributions of pollutant loads and associated impacts from wet-weather events, further research is required to better include temporally-differentiated emissions when evaluating eutrophication and ecotoxicity. This will provide a better understanding of how the performance of an UWS system affects the receiving environment for given local weather conditions.

International audience; This article presents a dual approach to assessing annual flows of metals and PAHs in stormwater for three urban watersheds of different land uses. An assessment of the contributions of primary sources of pollution, based on a SFA approach (substance flow analysis) is conducted so as to identify the relative contribution of emissions from automobiles (tires, brakes, fuel…), leaching from building materials (roof cover and singular elements of roofs) and atmospheric fallout. These flows are compared with those calculated at the outlet of the storm drainage system by a method combining the analysis of micro-pollutants in a limited number of stormwater samples and continuous measurement data of rain, flow and turbidity. This work allows to highlight the dominant diffuse sources of runoff contamination, key indicators for their quantification but also to diagnose gaps in current knowledge.; Cet article présente une double approche d’évaluation des flux annuels de métaux et de HAP dans les eaux pluviales de trois bassins versants urbains d’occupations du sol différentes. Une évaluation des contributions des sources primaires de pollution, par une approche de type « SFA » (analyse de flux de substances) est conduite afin d’identifier la contribution relative des émissions dues à l’automobile (pneus, freins, carburants…), au lessivage des matériaux de construction (couvertures et éléments singuliers de toitures) et aux apports atmosphériques. Ces flux sont confrontés à ceux évalués à l’exutoire du réseau pluvial par une méthode combinant l’analyse des micropolluants dans un nombre limité d’échantillons d’eaux pluviales et des données de mesure en continu de pluie, débit et turbidité. Ce travail permet de mettre en évidence les sources diffuses dominantes, des indicateurs clés pour leur quantification, mais aussi de diagnostiquer des lacunes dans les connaissances actuelles.

This study aimed at i) providing for a large range of pollutants (n=77) information on their occurrence and concentration ranges in stormwater, ii) assessing the land use influence on stormwater quality and iii) analyzing the contribution of total atmospheric fallout (TAF) and endogenous sources to this contamination. Additionally, for poorly documented pollutants such as nonylphenol and octylphenol ethoxylates (NPnEO and OPnEO), this study reported for the first time levels for some new concerning metals (As, Ti, Cr, V) and organic pollutants such as polybromodiphenylethers (PBDEs), some pesticides and bisphenol A (BPA). For most of the pollutants, the stormwater quality at the outlet of three urban catchments exhibiting a different land use patterns did not significantly differ, suggesting that land use does no significantly influence the stormwater micropollutant contamination. No significant difference in terms of partitioning between all sites was also observed, indicating the not site-dependence. Finally, the contributions of TAF to stormwater contamination for micropollutants were rather low or very low. This underlines not only for PAHs as previously demonstrated in the literature but also for a larger range of molecules such as BPA, NPnEO, OPnEO and PBDEs a high local production related to the leaching of urban surfaces, buildings and vehicles. Knowledge gained in this study may be used soon to elaborate relevant decision support tools for i) urban stormwater practitioners and/or ii) watershed managers to reduce stormwater pollutant discharges; Cet article synthétise les résultats du projet INOGEV sur les concentrations de micropolluants organiques et métalliques dans les eaux pluviales strictes. Ce projet a permis non seulement d'étudier certains polluants jusqu'à lors faiblement documentés dans la littérature mais également d'établir les ordres de grandeurs des concentrations totales, dissoutes et particulaires dans les eaux pluviales. Excepté pour quelques micropolluants pour lesquels le trafic automobile est une source importante de contamination (certains métaux, HAP) et les PBDE, aucune différence significative n'a été obserÎe entre les trois bassins versants étudiés, la variabilité inter-éÎnementielle des concentrations sur un même site étant du même ordre de grandeur que la variabilité inter-sites. De manière générale, la distribution des polluants entre phases dissoute et particulaire dépend des propriétés physico-chimiques des molécules. Les métaux sont préférentiellement associés aux particules :) > 50% for As, Cd, Mo, Ni, V, Cu et Zn; et > 80% for Co, Cr, Pb et Ti. Pour les composés organiques, cette répartition dépend fortement du coefficient octanol - eau (Kow). Au regard des processus de production et de transfert sur les surfaces urbaines, les résultats indiquent pour un large panel de molécules que les apports atmosphériques ne contribuent que minoritairement à la pollution obserÎe aux exutoires, leur contribution n'excédant généralement pas 30%. Démontré pour les métaux et les HAP à travers des études antérieures, ce résultat est innovant pour les autres molécules étudiées et vient confirmer une production locale importante.

La contamination en alkylphenols (AP) et en bisphenol A (BPA) des eaux de ruissellement urbaines est averee. Les sources potentielles de ces contaminants dans les eaux de ruissellement sont endogenes au bassin versant et sont liees en particulier a la circulation automobile et au lessivage des materiaux constituant l’enveloppe bâtie et les infrastructures urbaines. Cet article synthetise les resultats d’un travail experimental mene sur une selection de materiaux de construction, de materiaux et de consommables automobiles entrant en contact avec la pluie afin d’evaluer leur potentiel d’emission des AP, alkylphenols ethoxyles et BPA dans le ruissellement. 36 echantillons de materiaux, neufs et usages, appartenant a sept grandes familles de materiaux de construction (PVC, beton, polycarbonate, bitume modifie SBS, materiaux de drainage) et de materiaux automobiles (carrosserie, pneus) ont ete soumis a des tests de lixiviation au methanol puis, pour une selection d’entre eux, a des tests de lixiviation a l’eau. Trois types de fluides automobiles (liquide de frein, lave-glace et liquide de refroidissement) ont ete extraits directement. Les resultats demontrent la presence ubiquiste des composes recherches dans les materiaux urbains, ainsi que leur caractere extractible a l’eau. Les composes avec les plus forts taux d’emission sont le BPA et le nonylphenol (NP). Les emissions dans l’eau en BPA les plus importantes (10 a 300 ng/g) ont ete mesurees pour le polycar bonate, les pneumatiques, certaines carrosseries de voiture et les PVC. Le NP a ete lixivie par l’eau en quantite importante (1 a 10 ng/g) depuis les PVC, certains betons, les bitumes modifies SBS et les echantillons de carrosserie. Les pneus sont les seuls materiaux presentant une forte emission en octylphenol (OP) (1 a 10 ng/g). L’analyse de fluides automobiles a confirme la presence du BPA (0, 3 a 5, 5 g/L) et du NP (2, 3 a 2, 9 mg/L) dans les liquides de frein, tandis que les AP et le BPA peuvent etre trouves a l’etat de traces dans les liquides de refroidissement et lave-glaces.

International audience

International audience; This study investigates the effects of uncertainties associated with pollutant wash-off dynamics in the context of stormwater management practices modeling. A formal Bayesian approach is adopted for the calibration and the uncertainty analysis of a commonly used wash-off model under (1) the unverified assumption of homoscedastic, independent, and normally distributed residuals; and (2) using a more correct heteroscedastic and autoregressive error model. The results obtained for each of these approaches are compared, and the uncertainty associated with water quality modeling is later propagated through a conceptual best management practices (BMP) model for various stormwater management scenarios so as to assess the effect of this uncertainty for BMP modeling and clarify the benefits of a robust description of error structure. This study indicates that the violation of the statistical assumptions about the residuals may result in unreliable estimation of model parameters and total predictive uncertainty. However, the effect of the uncertainty in the intraevent variability of concentrations in runoff is found to have only a limited effect on the outputs of the BMP model, regardless of the error model adopted for calibration.

Stormwater runoff infiltration brings about some concerns regarding its potential impact on both soil and groundwater quality; besides, the fate of contaminants in source-control devices somewhat suffers from a lack of documentation. The present study was dedicated to assessing the spatial distribution of three heavy metals (copper, lead, zinc) in the surface soil of ten small-scale infiltration facilities, along with several physical parameters (soil moisture, volatile matter, variable thickness of the upper horizon). High-resolution samplings and in-situ measurements were undertaken, followed by X-ray fluorescence analyses and spatial interpolation. Highest metal accumulation was found in a relatively narrow area near the water inflow zone, from which concentrations markedly decreased with increasing distance. Maximum enrichment ratios amounted to > 20 in the most contaminated sites. Heavy metal patterns give a time-integrated vision of the non-uniform infiltration fluxes, sedimentation processes and surface flow pathways within the devices. This element indicates that the lateral extent of contamination is mainly controlled by hydraulics. The evidenced spatial structure of soil concentrations restricts the area where remediation measures would be necessary in these systems, and suggests possible optimization of their hydraulic functioning towards an easier maintenance. Heterogeneous upper boundary conditions should be taken into account when studying the fate of micropollutants in infiltration facilities with either mathematical modeling or soil coring field surveys.

Urban water is composed of a complex matrix of micropollutants produced by traffic and contributes to the degradation of the aquatic bodies without treatment before discharge toward the environment. Various solutions are available to manage or treat these pollutants loads. However, an in-situ evaluation of the efficiency of these solutions is still necessary. Within the framework of the ROULÉPUR project, four innovative source control solutions for the micropollutant loads stemming from runoff on urban streets are tested. These solutions are: i) a compact decantation/filtration/adsorption device, the STOPPOL ® 10CKF, Saint Dizier Environnement, ii) non-infiltrating stormwater biofilters, iii) vegetative filter strips and biofiltration/infiltration swales and iv) a vegetative pervious parking lot. Assessment of performance of these solutions requires measurement of both, quality and quantity of water at the inlet and outlet of each device over a period of at least one year. Continuous measurements that are also comparable between devices are quite difficult to achieve in the harsh urban environment. This paper seeks to present difficulties encountered and solutions in order to have accurate measurement for the four devices., Les eaux de voiries et parkings sont constituées d'une matrice complexe de micropolluants d'origines multiples (émissions liées au trafic et à l'environnement urbain – chauffage, usure du mobilier urbain, des bâtiments...), qui contribuent à la dégradation des milieux aquatiques lorsqu'elles ne sont pas traitées avant rejet. Diverses solutions techniques existent pour la maîtrise, voire un traitement à la source de ces flux polluants. Leur efficacité en termes d'abattement des micropolluants demande cependant à être évaluée in-situ. Dans le cadre du projet Roulépur, quatre solutions innovantes de maîtrise à la source des flux de micropolluants générés par le ruissellement sur les voiries urbaines sont testées. Ces quatre solutions sont : i) un dispositif compact de décantation/filtration/adsorption, le STOPPOL ® 10CKF de Saint Dizier Environnement, ii) des filtres plantés horizontaux non infiltrants, iii) des bandes enherbées et des fossés filtrants/infiltrants et iv) un parking perméable végétalisé Ecovégétal. L'évaluation de ces solutions nécessite des mesures combinées, de quantité et qualité des eaux, en entrée et en sortie de chaque dispositif, et ce pour des périodes de temps au moins annuelles. La nécessité d'avoir des mesures en continu et comparables entre les différentes solutions dans des environnements contraints complique la mise en oeuvre de l'instrumentation. L'objectif de cette communication est de présenter les difficultés liées à cette instrumentation et les solutions envisagées.

La collecte/utilisation des eaux de ruissellement de toiture s’est largement repandue chez les particuliers au cours des dernieres annees. Ce developpement ne s’est pas accompagne d’une reflexion sur la qualite de ces eaux. Or, lors de l’entretien des toitures, il est utilise des produits biocides qui vont servir a eliminer les vegetaux pouvant se developper sur la surface. Ces produits contiennent du chlorure de benzalkonium a des doses tres fortes (4 a 5 g/m² sur substance active pure). Dans cette etude, nous avons montre comment ce benzalkonium epandu sur le toit est lessive par la pluie et contamine l’eau recuperee. Ainsi, nos resultats montrent que la dynamique de lessivage pour la fraction dissoute est assez lente (dependant du materiau utilise pour la toiture). Or, la concentration residuelle dans l’eau de ruissellement reste superieure a 1 mg/L, meme apres plus de 50 mm ruisseles, ce qui est tres superieur aux EC50 relevees dans la litterature (~ 5 a 200 μg/L). Nous sommes donc en presence d’une situation a risque pour les usagers et le milieu recepteur.

Les emissions de metaux (13 especes metalliques) dans les eaux de ruissellement de 12 types de materiaux de toitures metalliques appartenant a cinq familles (zinc, cuivre, plomb, acier et aluminium) ont ete suivies sur bancs d’essai durant 14 mois en deux sites d’exposition en Ile-de-France. Les resultats ont permis d’evaluer les flux annuels emis par les differents materiaux et de hierarchiser ces materiaux en fonction de leur potentiel polluant. Un modele simple d’evaluation des emissions metalliques en fonction des conditions d’exposition (duree d’exposition, pluviometrie, geometrie du toit, materiau) est propose et valide sur des toits reels.