Bioavailability and bioaccumulation: a holistic approach

Bioavailability and bioaccumulation: a holistic approach

ED 398 Géosciences, Ressources Naturelles et Environnement
Proposition de sujet de thèse pour la rentrée universitaire 2015-2016
Bioavailability and bioaccumulation: a holistic approach Biodisponibilité et bioaccumulation : une approche intégrée Nom, label de l'unité de recherche (ainsi que l'équipe interne s'il y a lieu) : Centre de Géosciences, MINES ParisTech Localisation (adresse) : 35 rue Saint‐Honoré, 77305 Fontainebleau Nom du directeur de thèse HDR (et du co‐directeur s'il y a lieu) : Vincent LAGNEAU Nom, prénom et affiliation des co‐encadrants éventuels : Michael Descotes (Areva) Adresse courriel du contact scientifique : vincent.lagneau@mines‐paristech.fr et [email protected] Description du projet/sujet de thèse At the international level, today’s environmental regulation is becoming more ecosystems‐oriented. In Europe, according to the Water Framework Directive (EC, 2000), all water bodies should achieve a good ecological quality status by 2015, and at the latest 2021. In this respect, the target for the given standards is the habitat’s faunal biodiversity, meaning that the contaminants’ bioavailability is taken into account (Phrommavanh et al., 2013). Most of the Environmental Quality Standards (EQS) are internationally defined, however non priority substances EQS should be supplemented with national or local standards. Uranium (U) being classified as a non priority substance, its French EQS is being defined in terms of a dissolved concentration (Predicted No Effect Concentration – PNEC1) to be added to the background value, according to the Added Risk Approach ARA (IRSN, 2012). As the bioavailable fraction depends on the chemical speciation, it also varies with the geochemical conditions of the aquatic system. Therefore, on going studies propose conditional water EQS for U, based on the chronic PNEC value, according to several key parameters (alkalinity, pH and total dissolved organic carbon content, total hardness).However in the majority of AREVA’s former mines in France, the geochemical conditions correspond to the most critical case where the proposed 2 incremental EQS is 0.3 μg/L. This very low value is close to the one proposed in the Netherlands recently (van Herwijnen and Verbruggen, 2014), i.e. 0.17 μg/L as an increment to a background value fixed at 0.33 μg/L (the report mentions an absolute value of 0.50 μg/L as annual average in their report). The next step concerns the sediment Quality Standard (QS). Recently, a PNEC sediment of 4 mg/kg dried weight was proposed, in spite of an obvious gap of knowledge (Simon et al., 2014). Moreover, the bioavailable fraction in sediments is also geochemically and mineralogically dependant (Crawford and Liber, 2013), and this statement applies as well to the uranium natural background in sediments. Objectives In this evolving regulatory context, AREVA’s challenge will be to comply with these new standards downstream from former mines in France. An effective strategic action plan should cover the whole former mine cycle, from the tailings storage sites to the mine water treatment and ultimately the ecosystems downstream. Concerning the latter point, some of the key actions are to increase our knowledge (a) on the U bioavailability background (strictly related to natural weathering processes) and baseline (including anthropic activities) in sediments, (b) on the actual U bioavailability in ecosystems downstream from mining sites (both water and sediments), and (c) on the influence of the sediment mineralogy on U bioavailable fraction. To address these three points, the proposed study will include some field work (river sediments upstream and downstream from treated mine waters or, as an extreme case, in sediments of mine waters prior to treatment), laboratory work and geochemical modelings, which are detailed further in the planning table. The laboratory work will be based on an integrated approach combining (i) geochemical and mineralogical characterization of the exposure medium (sediment + porewater), (ii) bioavailability in situ measurement in the exposure medium (DGT3 device in porewater), (iii) bioaccumulation in living organisms, and (iv) modeling of the biogeochemical processes (speciation, sorption, BLM4). Indeed such an approach has already been undertaken for some metals, but not for uranium (Ferreira et al., 2013; Amato et al., 2014). The use of DGT for assessing uranium bioavailability in the exposure medium has been positively tested (Phrommavanh et al., 2014) and needs now to be confronted to the actual bioaccumulation. The relation between the DGT‐
bioavailable fraction and the bioaccumulation/toxicity will enable us to determine the consistency of the use of DGT in such a context. Lastly, geochemical modelings will be performed on the exposure medium (thermodynamic approach: water‐rock equilibrium, sorption, aqueous speciation) and completed with the Biotic Ligand Model BLM (Paquin et al., 2002; Niyogi and Wood, 2004). The advantage of a thermodynamic approch is to be able to model any physical‐chemical change on the bioavailable fraction and potentially the bioaccumulated fraction. Communications of the results obtained within this thesis will be encouraged through publications in international congress and peer review journals. Last, a period of 6 months will be dedicated at the end of the PhD thesis to the writing of the manuscript. Planning : The study is structured according to the planning in the accompanying excel document. This pluri‐disciplinary study will be performed in collaboration with several international partners. The estimated total time in each location is given below: AREVA Mines/R&D Dpt (France) ⇨ Field sampling / mineralogicalcharacterization ⇨ 8 % (3 months) University of Saskatchewan / Toxicology Centre (Canada) ⇨ Laboratory experiments ⇨ 33% (1 year) Free University of Brussels / Dpt of Analytical Chemistry and Pharmaceutical Technology (Belgium) ⇨ DGT device ⇨ 8 % (3 months) Mines ParisTech (France) ⇨ Speciation modelling / writing ⇨ 50 % (18 months) References ‐ Amato, E.D., Simpson, S.L., Jarolimek, C.V. and Jolley, D.F. (2014) Diffusive Gradients in Thin Films Technique Provide Robust Prediction of Metal Bioavailability and Toxicity in Estuarine Sediments. Environ. Sci. Technol., 48(8): 4485–4494. ‐ Csrawford, S. and Liber, K. (2013) Formulated lab vs. field sediment: Bioavailability of spiked uranium to Chironomus dilutus. Poster presented at SETAC Conference, Nashville, USA. ‐ EC (EUROPEAN COMMISSION), 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for community action in the field of water policy. Official Journal of the European Communities L327/1 22 December 2000. ‐ Ferreira, D., Ciffroy, P., Tusseau‐Vuillemin, M.H., Bourgeault, A. and Garnier J.M. (2013) DGT as surrogate of biomonitors for predicting the bioavailability of copper in freshwaters: An ex situ validation study. Chemosphere, 91: 241–247. ‐ Février, L. and Gilbin, R. (2015) Proposition de valeurs de PNECeau de l’uranium conditionnelles à des domaines physico‐
chimiques représentatifs des eaux douces françaises – Proposed values for uranium PNECwater, conditional upon physical‐
chemical ranges representatives of French surface waters. IRSN report IRSN/PRP‐ENV/SERIS/2014‐0028. ‐ IRSN (2012) Uranium : vers une norme de qualité environnementale pour les cours d’eau français. Journées SFRP Sections Environnement & Recherche et Santé, Paris, UIC, June 19th 2012. ‐ Niyogi, S. and Wood, C.M., 2004. Biotic ligand model, a flexible tool for developing site‐specific water quality guidelines for metals. Environmental Science and Technology, 38, 6177‐6192. ‐ Paquin, P.R., Gorsuch, J.W., Apte, S., Batley, G.E., Bowles, K.C., Campbell, P.G.C., Delos, C.G., Di Toro, D.M., Dwyer, R.L., Galvez, F., Gensemer, R.W., Goss, G.G., Hogstrand, C., Janssen, C.R., McGeer, J.C., Naddy, R.B., Playle, R.C., Santore, R.C., Schneider, U., Stubblefield, W.A., Wood, C.M. and Wu K., 2002. The biotic ligand model: a historical overview, Special issue: The biotic ligand model for metals – current research, future directions, regulatory implications. Comparative Biochemistry and Physiology, Part C 133, 3‐35. ‐ Phrommavanh, V and Gibeaux, A. (2013) Bioavailability of contaminants in the mining context – Literature review. AREVA report AMS‐DEXP‐DRD‐RT‐0008. ‐ Phrommavanh, V., Drozdzak, J., Leermakers, M. and Descostes, M. (2014) Mesure de la fraction biodisponible de l'uranium et du radium dans les eaux en contexte minier : optimisation de l'outil DGT. Journées Techniques SFRP "Eau, Radioactivité, Environnement", Paris, December 3‐4. ‐ Simon, O., Carasco, L., Gilbin, R. and Beaugellin‐Seiller, K. (2014) Résultats de tests d’écotoxicité en support de la détermination d’une norme de qualité spécifique du sédiment (QSsédiment) pour l’uranium – Ecotoxicity tests results as background material for determining a uranium sediment quality standard (QSsediment). IRSN report IRSN/PRPENV/ SERIS/2014‐00030. ‐ van Herwijnen, R. and Verbruggen, E.M.J. (2014) Water quality standards for uranium ‐ Proposal for new standards according to the Water Framework Directive. Dutch National Institute for Public Health and the Environment. RIVM Letter report 270006003/2014. ‐ Wang, Z., Zhao, P., Yan, C., Chris, V.D., Yan, Y. and Chi, Q. (2013) Combined use of DGT and transplanted shrimp (Litopenaeus vannamei) to assess the bioavailable metals of complex contamination: implications for implementing bioavailability‐based water quality criteria. Environ Sci Pollut Res Int., (6):4502‐15. Programme de rattachement/Financement : Thèse réalisée en collaboration avec AREVA. Connaissances et compétences requises : Profil recherché : profil chimie préféré (géochimie, chimie des surfaces ou biogéochimie), ingénieur ou master. 1‐ IRSN has determined uranium PNEC as 0.3 μg/L, by extrapolation using the assessment factor method (EC10 of 2.7 μg/L for Ceriodaphnia dubia, divided by a safety factor of 10). Indeed, current ecotoxicity data on uranium are not sufficient to apply a statistical extrapolation method (i.e. Species Sensitivity Distribution SSD, which assessment factor is between 1 and 5). 2‐ Note that this minimum value is lower than the WHO guide value for drinking water of 30 μg/L. 3‐ Diffusive Gradient in Thin films. 4‐ Biotic Ligand Mode.