LAboratoire de Spectrochimie Infrarouge et Raman – UMR 8516
random_4
  • Français
  • English
  • Spanish

Case studies on aquatic systems and water treatment

4.1 Ambient aerosols: Particulate pollution events in northern France
4.2 Screening of water bodies in the Nord-Pas de Calais Region (France)
4.3 The Deûle River
4.4 The Marque River
4.5 The Seine estuary
4.6 L’épuration de l’eau sur média filtrant

The study of aquatic systems and air quality necessitate numerous of scientific skills, associating generally in our projects chemists, biologists, geologists and/or eco-toxicologists. These research projects are focused on the monitoring of air pollution by aerosols in real time, on the fate of pollutants in surface sediments, whose behaviors are linked directly to the early diagenetic processes, on the pollutant exchanges at the interfaces, and finally on the dynamic speciation of contaminants in fresh and sea waters. In parallel, other studies deal with water treatments (production of drinking water and waste water treatment); these researches are partly in relation with the Master “Water Treatment” chaired by a professor belonging to LASIR Laboratory (M. Baghdad Ouddane).

4.1 Ambient aerosols: Particulate pollution events in northern France

Staff involved: M. Choël (MCF)

Fig. 1. Observation platform on the rooftop terrace of a 3-storey university building.

Aerosols are defined as a suspension of liquid or solid particles in a gas. In ambient air, the sizes of suspended particles vary from a few nanometers to a few tens of micrometers (ultrafine < 1 μm, fine 1 – 2.5 μm and coarse particles 2.5 – 10 μm). The predominant chemical components of particulate matter are sea salt, mineral dust, metallic particles, sulfates, nitrates, ammonium, organic and carbonaceous compounds. The size, morphology, chemical composition and mixing state (homogeneous, external and internal mixture) of atmospheric particles are spatially and temporally highly variable, due to the physicochemical transformations (e.g., coagulation, heterogeneous reactions, hygroscopic growth) experienced during transport.

This work aims at better understanding of particulate pollution events at local, regional and global scales by the combination of remote sensing observations (in collaboration with “Laboratoire d’Optique Atmosphérique” and in situ measurements particle counter installed on the platform of the “Observatoire des Sciences de l’Univers” OSU-Nord) (Fig. 1).

Aerosol particles in the PM10, PM2.5-10 and PM1-2.5 fractions are collected by cascade impaction (Fig. 2).

Offline laboratory analysis is conducted at the particle scale using different microscopy techniques such as analytical scanning and transmission electron microscopy (SEM and TEM/EDX), atomic force microscopy (AFM) and Raman microspectrometry (Fig. 3).


Fig. 2. Temporal evolution of aerosol mass concentrations (in µg/m3): PM10 (red), PM2.5 (blue) and PM1 (green).


Fig. 3. TEM image of atmospheric particles collected in Lille during a fine particulate pollution event in March 2014.

This work is conducted in the framework of CaPPA project (Chemical and Physical Properties of the Atmosphere) funded by the French National Research Agency (ANR) through the PIA (Programme d’Investissement d’Avenir) under contract “ANR-11-LABX-0005-01”.

Haut de page

4.2 Screening of water bodies in the Nord-Pas de Calais Region (France)

Staff involved: B. Ouddane (Pr), S. Net-David (MCF), D. Dumoulin (IR)

Several watercourses and rivers located in the Hauts de France region have been characterized with the support of the Regional Water Agency. Contamination levels and dispersion of organic contaminants in different phases of the aquatic environment (dissolved phase, suspended solid matter, and sediments) have been studied to better understand their consequences on the aquatic ecosystem.

The Figure above presents the distribution of the sum of six phthalates (DMP, DEP, DBP, BBP, DEHP and DnOP) classified as priority substances in the list of US-EPA and among them, DEHP has been classified as priority hazardous substance in the Water Framework Directive (Fig. A) and 14 drug residues (Fig. B) in water, the suspended particles and sediment. 15 stations located in in six river catchment of the Scheldt (Net et al., 2015, Sci Total Environ) have been studied. The water and sediment of the Scheldt seem to be less contaminated with phthalates compared to 5 other rivers and the Scarpe was the highest contaminated with phthalates (Fig. A). High concentrations of phthalates were also detected in the sediments of the Scarpe. For the selected drug residues, even if low concentrations are detected in the water of the Scarpe their concentrations in sediment were significant. A previous study reported also that the Scarpe were also heavily contaminated with PAHs and PCBs compared to the Deûle and the Sensée Rivers (Net et al., 2015, J Geochem Explor). The concentrations of drug residues detected in the Deûle, the Lys and the Scheldt varies greatly between stations (Fig. B). This could be due to influence of local sources of contamination on each station.

Haut de page

4.3 The Deûle River

Staff involved: G. Billon (Pr), B. Ouddane (Pr), L. Lesven (MCF), P.J. Superville (MCF)

The Deûle River is a canal situated in the north of France, in the Scheldt watershed. It is strongly impacted by the metal smelting industry which has been active on its banks since the beginning of the 20th century (mostly Pb and Zn). Around the former Metaleurop industrial site, the sediments remain extremely contaminated with Pb and Zn, but also Cd, Hg… Furthermore, the Deûle River is navigated, which leads to the daily resuspension of sediments in the overlying waters. Numerous studies have been made (on line and off line) on the trace metal behavior, i.e. on their potential mobility in the water column and their bioavailability towards aquatic organisms. It has been showed for instance that: (i) the variation of the water quality is more dependent on the seasons than on the contaminated sediment remobilization; (ii) although the sediments are highly contaminated, the contaminants are not very available due to high concentration of sulphide precipitates; (iii) the bacterial community has developed some metal resistance genes, in correlation, not with dissolved metals, but with metals weakly adsorbed at the particles surface; and (iv) the exposition of gammarus as well as the use of DGT probes have not clearly evidenced a much greater mobility of metals in the overlying water of the Deûle in comparison with other sites less contaminated (like the Sensée canal).

 CdPbZnCuMnNi
Exchangeable fraction (mg kg-1)0,98161110,05520,52
Total concentration (mg kg-1)133431063341076,4

Average concentrations measured in the surface sediment near the former Zn and Pb smelting plant Metaleurop. The exchangeable fraction corresponds to the first extraction of the BCR sequential extraction protocol ([CH3COOH] = 0,11 mol L-1).

Variation of the acid-leachable fraction of Pb (pH=2) in the Deûle River during four on-line monitoring periods of 2011. The electrolabile Pb at natural pH is shown in red for comparison. These measurements have been performed using an automatic trace metal monitoring system (Superville et al., 2014). A strong increase of the Pb mobility was observed during Spring and Summer. It was explained by shorter redox cycles of iron and manganese in the surface sediment which are regularly resuspended in the overlying waters.

Haut de page

4.4 The Marque River

Staff involved: G. Billon (Pr), J. Criquet (MCF), L. Lesven (MCF), D. Dumoulin (IR)

The Marque River is a natural watercourse located in Northern France going through agricultural and urban areas. Strongly impacted by numerous pollutants, the river receives two main anthropogenic inputs (a public Waste Water Treatment Plant and a storm overflow) in the city of Villeneuve d’Ascq. The marque river has a poor quality due to high concentrations of phosphorous, nitrogen, PAH… A project “Researchers-Citizens” financed by the Hauts de France Region (2013-2016) looks at the different inputs into the river with different spatial and time scales. In addition, the Heron lake, a storm overflow is studied with a periodical screening of the water and sediments; an instrumented buoy has also been deployed for 1 year in 2015.

Evolution of the different Zn fractions (electrolabile, leachable at acidic pH) followed by voltamperometry (ATMS: Automated Trace metal Monitoring System) from June 23th to July 24th in the Marque River. High increases are observed during rain events (precipitations: black line) and daily cycles are observed during the dry periods.

Study site of the OPUR project (Effluent inputs and water quality in urban area, The Marque river at Villeneuve d’Ascq).

Haut de page

4.5 The Seine estuary

Staff involved: B. Ouddane (Pr)

The Seine River and its estuary are known for their historical pollution. The studies of this site were initiated since the 1980s in various national and international research programs (GRECO-Manche, SEINEAVAL-1 to SEINEAVAL-5, PNETOX, MAST, INTERREG RIMEW…). Several PhD theses on trace metals and organic contaminants were dedicated to this site, both in the water column and in the sediment compartment (Nganou 1985; Ouddane 1990; Martin 1996; Bodineau 1996; Beghin 1998; Skiker 1998; Billon 2001; Foucher 2002; Clarisse 2003; Ghiasse 2003; Msocar 2003; Hamzeh 2012).

The recent researches are focused on sediments processes, deposited or (re)suspended in the different mudflats. These sites are a privileged support for various chemicals and can have a double action on pollution, processing (treatment of chemical contaminants, nutrients) and ecological function (nursery, abundance of benthic fauna and flora). The sediment deposition is not permanent but there is more resuspension linked to dynamic natural processes (river flow, tidal currents, waves …) or induced by human activities (dredging, infrastructure construction operations). This area is a source (both for particulates and dissolved elements) and also related fine particulate trapping landfill sites which causes rapid favourable reducing conditions (diagenetic process). Such media promote the production of sulphides by microbial communities activity and their precipitation with several metals. The importance of these processes has been demonstrated in several studies conducted in the SeineAval program.

Site d’étude de la Seine et son estuaire (Programme SEINEAVAL).

Haut de page

4.6 L’épuration de l’eau sur média filtrant

Staff involved: B. Ouddane (Pr), A. Boughriet (MCF), M. Wartel (Pr)

Malgré les ressources importantes en eau dans certains pays d’Asie ou d’Afrique la population ne dispose pas d’eau de qualité potable et la question se pose cruellement de traiter l’eau à moindre coût. Au niveau de l’équipe, nous nous sommes intéressés à la technique d’adsorption sur des supports de types argileux modifiés comme les résidus de la brique locale. Ce matériau adsorbant est aisément accessible pour une utilisation dans la purification de l’eau en milieu rural. Après traitement acide et dépôt de ferrihydrite, la brique s’est avérée être un bon adsorbant par échanges d’ions. L’influence de paramètres : temps de contact, température, masse d’adsorbant et pH, ont été étudiés avec des applications sur cas réels (eau de rivière).

L’étude des cycles d’adsorption/désorption sur colonne a permis de mettre en évidence l’implication des espèces H+ et Na+ à l’interface « brique-eau » (thèse Oscar Allahdin, 2014). Ce procédé a également été appliqué à l’élimination de phosphates de l’eau. Les résultats ont montré que selon le traitement préalable, cations ou anions sont adsorbés grâce aux charges opposées entre la surface du solide et les ions dans l’eau.

Une autre application de terrain a été menée en République Centrafricaine par la construction d’un pilote de filtration horizontale, pays dont les besoins en eaux potables sont criants. Le pilote a été construit selon les recommandations de la Sté « Eaux de Paris », le système a été alimenté par les eaux de l’Oubangui. Le suivi des performances et de la qualité des eaux produites durant une année et demie a montré que le pilote correspondait bien aux critères des normes exigées pour une eau brute avant désinfection (avec une production de 400 l/h). Ce type de pilote permet un traitement simple de l’eau de rivière, nécessitant un minimum d’énergie et peu de produits de traitement. La filtration lente sur sable apparaît comme une réplique des processus naturels d’infiltration dans le sol. Par comparaison avec les sables originels ayant été utilisés dans la conception du pilote, les résultats ont montré que la capacité d’adsorption des sables est améliorée en raison de modifications de surface et de dépôts d’argile et oxydes/hydroxydes de fer dans les interstices et fissures produits par effet d’érosion dû à l’écoulement des eaux (thèse Eric Foto, 2015).

Haut de page