Beatrice Bechet - Academia.edu (original) (raw)

Papers by Beatrice Bechet

&lt;p&gt;The management of urban stormwater runoff has moved from approaches narr... more &lt;p&gt;The management of urban stormwater runoff has moved from approaches narrowly focused on reducing flooding to approaches more focused on improving water quality. From impervious surfaces, stormwater is often diverted into retention ponds where sedimentation is used to limit the impact on waterbodies by trapping particulate pollutants. Trace elements are of particular interest because of their potential toxicity. The composition of the sediment varies over time, particularly through the development of vegetation. Ageing has an effect on sediment removal ability of pollutants (Nuel et al., 2018). The aim of this study was to compare the mobility of trace elements in sediments of a retention-infiltration pond before and after its total dredging. The mobility of these pollutants is related to their geochemical fractionation between solid phases which is generally investigated by extraction methods. The single extraction method with ammonium acetate and calcium chloride was applied on sediment samples to quantify the highest labile fraction of these elements (Sakan et al., 2020). The ultrasound assisted sequential extraction based on the procedure proposed by Rauret et al., (2000) and certified by Pueyo et al., (2001) was applied to determine the pollutant distribution among the acid-extractable, reducible, oxidizable fractions of sediments. The ageing effect is examined to explain the global removal ability of sediments. Then, the distribution of trace elements in different solid phases is analyzed in function of the sediment ageing, the mineral composition and granulometry of sediments.&lt;/p&gt;&lt;p&gt;&lt;em&gt;Nuel, M., Laurent, J., Bois, P., Heintz, D., Wanko, A., 2018. &lt;/em&gt;&lt;em&gt;Seasonal and ageing effect on the behaviour of 86 drugs in a full-scale surface treatment wetland: Removal efficiencies and distribution in plants and sediments. Science of The Total Environment 615, 1099&amp;#8211;1109. https://doi.org/10.1016/j.scitotenv.2017.10.061&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Pueyo, M., Rauret, G., L&amp;#252;ck, D., Yli-Halla, M., Muntau, H., Quevauviller, Ph., L&amp;#243;pez-S&amp;#225;nchez, J.F., 2001. Certification of the extractable contents of Cd, Cr, Cu, Ni, Pb and Zn in a freshwater sediment following a collaboratively tested and optimised three-step sequential extraction procedure. J. Environ. Monitor. 3, 243&amp;#8211;250. https://doi.org/10.1039/b010235k&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Rauret, G., L&amp;#243;pez-S&amp;#225;nchez, J.-F., Sahuquillo, A., Barahona, E., Lachica, M., Ure, A.M., Davidson, C.M., Gomez, A., L&amp;#252;ck, D., Bacon, J., Yli-Halla, M., Muntau, H., Quevauviller, Ph., 2000. Application of a modified BCR sequential extraction (three-step) procedure for the determination of extractable trace metal contents in a sewage sludge amended soil reference material (CRM 483), complemented by a three-year stability study of acetic acid and EDTA extractable metal content. J. Environ. Monitor. 2, 228&amp;#8211;233. https://doi.org/10.1039/b001496f&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Sakan, S., Fran&amp;#269;i&amp;#353;kovi&amp;#263;-Bilinski, S., &amp;#272;or&amp;#273;evi&amp;#263;, D., Popovi&amp;#263;, A., &amp;#352;krivanj, S., Bilinski, H., 2020. Geochemical Fractionation and Risk Assessment of Potentially Toxic Elements in Sediments from Kupa River, Croatia. &lt;/em&gt;&lt;em&gt;Water 12, 2024. https://doi.org/10.3390/w12072024&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;&amp;#160;&lt;/em&gt;&lt;/p&gt;

HAL (Le Centre pour la Communication Scientifique Directe), Sep 4, 2023

HAL (Le Centre pour la Communication Scientifique Directe), Sep 11, 2023

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

International Journal of Sediment Research, Dec 1, 2018

Sustainable urban drainage systems are built along roads and in urban areas to collect urban runo... more Sustainable urban drainage systems are built along roads and in urban areas to collect urban runoff and avoid flooding, and to filter water pollutants. Sediment collected by runoff is deposited in the stormwater basin and progressively reduces water infiltration efficiency, leading to the clogging of the basin. To help stormwater basin managers and stakeholders better understand and predict clogging rates in order to elaborate maintenance plans and schedules, water transport prediction models are necessary. However, because of the heterogeneous sediment hydrodynamic properties inside the stormwater basin, a twodimensional (2-D) water flow model is required to predict water levels and possible overflow as accurately as possible. Saturated hydraulic conductivity (Ks) and sediment water retention curves were measured in the overall sediment layer of the stormwater basin, in addition to sediment layer thickness and organic matter content (11 sampling points). Sediment depth was used to predict organic matter (OM) content, and the OM was used to predict Ks. Water height in the basin was modeled with the HYDRUS-2D model by taking into account the sediment hydrodynamic properties distribution. The HYDRUS-2D model gave a satisfactory representation of the measured data. Scenarios of the hydraulic properties of stormwater basin sediment were tested over time, and hydraulic resistance, R, was calculated to assess the stormwater basin performance. Presently, after 20 years of functioning, the stormwater basin still ensures efficient water infiltration, but the first outflow (Hydraulic resistance, R > 24 h)) is expected to appear in the next 5 years, and clogging (R > 47 h) in the next 13 years. This 2-D water balance model makes it possible to integrate the hydrodynamic heterogeneity of a stormwater basin. It gives interesting perspectives to better predict 2-D/3-D contaminant transport.

HAL (Le Centre pour la Communication Scientifique Directe), Oct 3, 2011

$Research paper thumbnail of Size fractionation highlights the mobility of copper from urban stormwater to river$

Copper is an ubiquitous essential element but also toxic to aquatic organisms, Environme... more Copper is an ubiquitous essential element but also toxic to aquatic organisms, Environmental Quality Standards being 1 µg.L-1 for surface water (annual mean concentration). Rivers and estuaries are mainly concerned by copper accumulation in sediments and in organisms. Copper can originate from various manufactured products (antifouling painting, vineyards fungicides, brake linings….) and anthropic activities (industrial, landfills…). As a result, copper French median concentration in oysters is about 200 mg.kg-1 DM (Ifremer, 2017).Transportation, especially road transport, is the main French source of copper air emissions (92% of total emissions) (CITEPA, 2019). Then, urban areas, mainly impervious, constitute a major non-point source of copper from abrasion of brake pads and tires, and fuels. This contaminant is released from the road surfaces through stormwater runoff directly to water bodies or after collection in sustainable urban drainage systems (SUDS). As the epuration performance of SUDS for copper was shown to be low, this study is carried out to evaluate if copper mobility can be explained by its physical speciation. The distribution of copper among dissolved, colloidal and particulate fractions is studied by size fractionation, assuming that the mobility of copper is related to a high dissolved and colloidal occurrence.The study site is a retention-infiltration basin collecting the runoff waters of the main bridge of Nantes (France; about 90 000 vehicles/day), and overflowing to the Loire river . Size fractionation by in series filtration and ultrafiltration was performed on stormwater runoff and surface waters sampled within the basin. Five fractions were analyzed for major and trace elements: ] ; 8µm ], ] 8µm ; 1,2µm ], ] 1,2µm ; 0,45µm ], ] 0,45µm ; 5kDa ] and ] 5kDa. Among these fractions ] ; 8µm ] correspond to particulate copper, ] 8µm ; 1,2µm ], ] 1,2µm ; 0,45µm ], ] 0,45µm ; 5kDa ] to colloidal copper and ] 5kDa ; [ to dissolved copper. Size fractionations were implemented for 8 samples with 2 replicates for each sample and over 1 year. 0.45 µm filtrations were also conducted as a reference.The total copper concentration in runoff was around 100µg.L-1, which is in the upper part of the concentrations observed in the area of Nantes in SUDS. The results of the size fractionation are as follows : 1) for the stormwater runoffs, particulate copper is about 70% of the total amount, colloidal copper is present for 20% and 10% of dissolved copper is measured. Thus 30 % of copper are mobile; 2) for the surface waters in the basin, the distribution of copper among the dissolved, colloidal and particulate fractions, is respectively 20 %, 70 % and 10 %.We concluded that 1) the concentration of copper is 100 times higher the regulation value for natural environment, and 2) particulate fractions of copper are trapped at the entrance of the basin, and an high content of mobile copper (dissolved and colloidal fractions) is observed in the basin that could either be overflowed or infiltrated in the sub-soil of the basin.

Projets de paysage, Dec 30, 2022

Ce travail a reçu le soutien financier de la Commission européenne, via le programme de recherche... more Ce travail a reçu le soutien financier de la Commission européenne, via le programme de recherche-innovation Horizon 2020 (Grant agreement n o 776783), projet Urbinat. Il a été réalisé au sein de la Fédération de recherche IRSTV (CNRS FR 2488). 1 Volonté de recomposer la territorialité des productions alimentaires (Ernwein et Salomon-Cavin, 2014), et demande sociétale forte de jardins urbains renouvellent actuellement l'attention portée aux sols. Le jardinage urbain actuel revêt une grande diversité de formes : jardins familiaux et partagés, parcs potagers, vergers urbains, etc. Leurs multiples bénéfices (sociaux, économiques, éducatifs, environnementaux, santé) justifient leur essor en France et le fait que les municipalités favorisent cette dynamique (Demailly, 2015) 2 Le jardinage urbain interroge la qualité des sols, tant en sciences du sol que dans les sciences humaines et sociales. En effet, l'artificialisation des sols (péri)urbains conduit à une dégradation de leurs potentialités agronomiques (Chalmandrier et al., 2017). Les sols suscitent aussi des inquiétudes en matière de risques sanitaires puisque nombre d'entre eux sont implantés sur des délaissés urbains, des friches ou sont à proximité d'infrastructures de transport (

HAL (Le Centre pour la Communication Scientifique Directe), Feb 20, 2018

HAL (Le Centre pour la Communication Scientifique Directe), 2016

International audienc

Hydrology and Earth System Sciences, Feb 12, 2021

The effect of macropore flow on solute transport has spurred much research over the last forty ye... more The effect of macropore flow on solute transport has spurred much research over the last forty years. In this study, non-reactive solute transport in water-saturated columns filled with porous media crossed by a macropore was experimentally and numerically investigated. The emphasis was put on the study of exit effects, whose very existence is inherent to the finite size of any experimental column. We specifically investigated the impact of a filter at the column outlet on water flow and solute transport in macroporous systems. Experiments involving breakthrough measurements and magnetic resonance imaging (MRI) showed that solute transport displayed some significant nonunidirectional features, with a strong mass exchange at the interface between the macropore and the matrix. Fluid dynamics and transport simulations indicated that this was due to the non-unidirectional nature of the flow field close to the outlet filter. The flow near the exit of the column was shown to be strongly impacted by the presence of the outlet filter, which acts as a barrier and redistributes water from the macropore to the matrix. This impact was apparent on the breakthrough curves and the MRI images. It was also confirmed by computer simulations and could, if not properly taken into account, impede the accurate inference of the transport properties of macroporous media from breakthrough experiments.

Science of The Total Environment, Nov 1, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

EGU General Assembly Conference Abstracts, Apr 1, 2019

HAL (Le Centre pour la Communication Scientifique Directe), Jun 25, 2007

Rôle des colloïdes dans le transfert des éléments traces dans un bassin de rétention-infiltration

HAL (Le Centre pour la Communication Scientifique Directe), Sep 16, 2013

L'infiltration des eaux de ruissellement dans des bassins dedies en assainissement pluvial co... more L'infiltration des eaux de ruissellement dans des bassins dedies en assainissement pluvial conduit a s'interroger sur le devenir des polluants metalliques transportes par ces eaux et presents en solution soit sous forme de solute, soit en association avec des particules colloidales. Le transfert des metaux dans les sols des bassins va dependre notamment de l'heterogeneite du sol, en terme d'ecoulement mais aussi en terme de capacite de retention de ses constituants mineraux et organiques. L'influence de l'heterogeneite sur les transferts est presentee par deux exemples d'experimentation en colonne de laboratoire. Le premier permet de mettre en evidence l'importance de l'heterogeneite de l'ecoulement sur le transfert reactif de metaux traces (Pb, Zn, Cd) dans un depot fluvio-glaciaire. Le second montre que le transfert de particules colloidales modeles (latex) dans un sable a ecoulement homogene ne peut etre decrit qu'a l'aide d'un modele prenant en compte une heterogeneite surfacique d'adsorption des grains de quartz. (A). (Voir fiche generale F101003 et fiches specifiques F101004 a F101084).

HAL (Le Centre pour la Communication Scientifique Directe), Nov 24, 2015

HAL (Le Centre pour la Communication Scientifique Directe), Jun 5, 2018