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Reference : UMR5243-HELOUR-010
Workplace : MONTPELLIER
Date of publication : Thursday, August 01, 2019
Scientific Responsible name : Pierre Camps
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2019
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Magnetic and Geochemical bio monitoringof the emissions of fine particles ans anthropic origin in peri urban environment.
According to the latest reports of the World Health Organization  air pollution to fine particles is a major societal challenge because responsible for more than 3 million deaths worldwide per year and 85 million years lost in life expectancy in good health (DALY indicator). These figures are still worrying in France, where, according to these reports, there are about 11,000 annual deaths directly attributed to poor indoor air quality. The monitoring of the concentrations of fine particles and a good knowledge of their emission sources are two important points in the consideration and treatment of this health risk in order to develop adapted plans to reduce its dangerousness. Environmental magnetism is a relatively new science developed in the 1980s for the study of soils and sediments in paleoclimatology issues. Technological developments are making it possible today to detect extremely weak magnetic signals on different types of materials. In particular, the pioneering work of B. Maher and her collaborators - have shown that it is possible to monitor fine particles deposited on plants by applying these rock-magnetism techniques on plant-leaf or bark samples (see  for a review). However this remains surprisingly today at a qualitative level. The most difficult and technical task in this project will be to calibrate the physical parameters of environmental magnetism  such as precise indicators of the concentration level of the metals present in airborne particles in the peri-urban environment, but also the nature of these metals, and so their origin. This challenge has never been raised before . We believe that we can meet it with the experimental site of Saint-Aunès: three vegetated mounds bordering the highway have been built by ASF company and Saint-Aunès city. The population expectations on the air quality issue coincide with effective ways and means of evaluating the efficiency of tree hedgerows on air quality. Remarkable and most likely unique, this experimental site was instrumented in July 2017 with two weather stations, 13 stations equipped with NO2 passives samplers, 10 sites where repeated measurements of NO2 and particulate matter are performed with a mobile station, and 8 fixed stations equipped with μ-sensors of particulate matter. The system has been designed and operated for a 10-year-monitoring of air quality by ATMO-Occitanie, which is the regional state-approved agency. Besides, a half time-position have been created by ASF company to monitor the vegetation growth. Finally, a part of the project has been funded by the ASF company to build up an experimental test bench in which we will be able to control the dry deposit of different pollutants on various local plant species. Last but not least, the implementation of isotopic geochemistry analysis allowing somehow to describe the 'DNA' of the metals and thus to trace their origin will be a key point to reach the first challenge we describe right before. As final products developed, we intend to produce from magnetic measurements high-resolution qualitative maps of particulate matter deposited on tree leaves all over the city of Saint-Aunès and its close surroundings. These maps will be confronted to the numerical modelling of pollutant dispersion performed with the help of ATMO-Occitanie engineers.
 World Health Organization, Ambient air pollution: A global assessment of exposure and burden of disease, 2016.
 B.A. Maher, C. Moore, J. Matzka, Spatial variation in vehicle-derived metal pollution identified by magnetic and elemental analysis of roadside tree leaves, Atmospheric Environment, 42, 364–373, 2008.
 R. Mitchell, B.A. Maher, Evaluation and application of biomagnetic monitoring of traffic-derived particulate pollution, Atmospheric Environment 43, 2095–2103, 2009.
 P. Camps et al., Magnetic biomonitoring of particulate pollution in the city of Montpellier (France): The relative contribution of vehicles and trams., 15th castle meeting, Dinant, 2016.
 J. Hofman, B. A. Maher, A. R. Muxworthy, K. Wuyts, A. Castanheiro, and R. Samson, “Biomagnetic Monitoring of Atmospheric Pollution: A Review of Magnetic Signatures from Biological Sensors,” Environmental Science and Technology, vol. 51, no. 12. pp. 6648–6664, 2017.
The thesis will be carried out at the Géosciences Montpellier laboratory, under the supervision of Pierre Camps and Delphine Bosch. The Géosciences Montpellier laboratory is a research unit (UMR5243) supported by the Centre National de la Recherche Scientifique (CNRS) and the Université de Montpellier. On site, we have access to a large number of facilities and state-of-the-art equipment, at the rock magnetism laboratory (cryogenic magnetometer, impulse magnetizer, susceptibility meters etc…) and within the geochemical platform including ultraclean laboratories devoted to chemical preparation and isotope purification; MC-ICP-MS and HR-ICP-MS. FTIR, Mossbauer and Micro-Raman spectrometers, EBSD, TEM and SEM are available through the University common facilities.
Constraints and risks
Calibration of the magnetic bio-monitoring technique is an ambitious challenge. A lot of patience and meticulousness in sample preparation and analysis will be required to obtain quality data. Some analyzes may require a presence in the laboratory and on the experimental site of Saint-Aunès outside usual hours of work. The field will be in the metropolises of Montpellier and Toulouse and their peri-urban territory, under the supervision of the thesis director and / or members from the laboratory Geosciences Montpellier or from the laboratory of Geosciences and Environment of Toulouse.
The project is multidisciplinary. The candidate must have skills in at least one of the following areas.
- experimental measurement in environmental magnetism or rock magnetism.
- experimental measurement in elemental and isotopic geochemistry
- Numerical modelling of the dispersion of air pollutants.
In addition, we are looking for candidates with excellent Master's degree (or equivalent degree). Candidates should have a strong team spirit, scientific creativity and problem-solving skills and able to work independently; high motivation / ability to work in the field; excellent English skills (written and spoken).
Salary and support for research activities are funded by ANR BREATHE (PI: P. Camps)
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