Description of the thesis topic

Title : Study of the role of a wetland on the retention of metals (Pb, Mn, Co, Cs) and iodine (I) : Case of the Rhine hydrosystem.

Wetlands, located at the interface between atmospheric, terrestrial and aquatic compartments, are capable of storing organic matter (OM) and atmospheric CO2, thus playing a crucial ecological regulatory role. Stored OM also gives them the capacity to trap various micropollutants in (river) hydrosystems, including metallic and organic micropollutants. They are also capable of retaining elements that are highly mobile in other environments, such as iodine. However, this water filtration function can be affected by changes in environmental parameters, such as those induced by global climate change. It is therefore cruciel to examine the internal processes of wetlands that contribute to the retention - or potential release - of micropollutants, particularly under the influence of these changes. This thesis focuses on the study of a wetland (bank)-water-sediment continuum in the Rhine river hydrosystem. This hydrosystem is subject to significant anthropogenic influences, including industrial, urban and agricultural activities responsible for discharges of micropollutants, such as iodine (I), trace metal elements (TMEs), and organic molecules (drug residues, pesticides, etc.), which exert pressure on the terrestrial and aquatic environments. In particular, little is known about the accumulation of organic micropollutants in wetlands and their interactions with metallic micropollutants. The objectives of the thesis are to identify the transfer of iodine (I) and TMEs (Pb, Mn, Co, Cs) in the continuum, and the interactions between micropollutants, OM and minerals that control them. The studies will focus on three parts:

1) Fine characterization of the soil-water-sediment continuum of the wetland: quantifying I and TMEs, quantifying and identifying the organic molecules that make up OM.
2) Elucidate the transfer mechanisms of I and TMEs in the continuum: quantify in natura the available and mobile fractions, and identify the chemical species involved (colloidal, organic, inorganic, etc.).
3) Anticipate the role of key physico-chemical parameters on interactions and transfers, through laboratory studies of mineral-OM-TEMs model systems.

The planned work combines multi-scale studies of the continuum under consideration with laboratory experiments, and includes environmental sampling, field analysis using in-situ sensors, chemical analysis of various matrices, and molecular analysis using advanced spectroscopic/spectrometric techniques.

Work Context

The Hubert Curien pluridisciplinary Institute (IPHC, UMR 7178), a joint research unit co-supervised by the CNRS and the University of Strasbourg (UMR7178), is a multidisciplinary laboratory where research teams from different scientific backgrounds (ecology, physiology and ethology, chemistry and subatomic physics) develop top-level programs based on scientific instrumentation. The IPHC is organized into 3 departments and has a total staff of 393 (M/F), including 257 permanent employees (119 researchers and teacher-researchers and 138 engineers and technicians M/F), 46 employees on fixed-term contracts and 102 PhD students M/F.
The PhD student's work will take place in the IPHC radiochemistry group on the CNRS Cronenbourg campus. The candidate will be supervised by Dr. Lu Liu (lu.liu@iphc.cnrs.fr) and Dr. Mirella Del Nero (mireille.delnero@iphc.cnrs.fr).

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.

Additional Information

The candidate must have a Master's 2 or equivalent degree in chemistry, geochemistry or physical chemistry, including a solid initial training in solution chemistry. Experience in environmental chemistry would be a plus. Applications must include a CV, a cover letter and transcripts obtained in Master 1 and 2.