RAMR2D network scholarship holders
Affiliated CEAs :
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CEA-2IE: CEA for training and research in water, energy and environmental sciences and technologies in West and Central Africa
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CEA-MS: Centre Emergent Mines et Sociétés of the Institut supérieur des mines de la géologie de Boké in Guinea
Supervision :
Stépahne Guédron, Institute of Earth Sciences, stephane.guedron@univ-grenoble-alpes.fr
Co-supervision
Ynoussa Maïga, Joseph KI-ZERBO University, ynoussa.maiga@gmail.com
Other supervisors and contributors :
Jacques Gardon, Hydrosciences Montpellier, gardon@ird.fr
Odile Bruneel, Hydrosciences Montpellier, odile.bruneel@ird.fr
Ahmed Amara Konaté, Institut Supérieur des Mines et Géologie de Boké, konateahmeda@gmail.com
Additional funding obtained: LabEx OSUG - AO International bis 2023, BQR_Isterre
Djamilatou DABRE
Affiliated CEAs :
-
CEA-2IE: CEA for training and research in water, energy and environmental sciences and technologies in West and Central Africa
-
CEA-MS: Centre Emergent Mines et Sociétés of the Institut supérieur des mines de la géologie de Boké in Guinea
Supervision :
Stépahne Guédron, Institute of Earth Sciences, stephane.guedron@univ-grenoble-alpes.fr
Co-supervision
Ynoussa Maïga, Joseph KI-ZERBO University, ynoussa.maiga@gmail.com
Other supervisors and contributors :
Jacques Gardon, Hydrosciences Montpellier, gardon@ird.fr
Odile Bruneel, Hydrosciences Montpellier, odile.bruneel@ird.fr
Ahmed Amara Konaté, Institut Supérieur des Mines et Géologie de Boké, konateahmeda@gmail.com
Additional funding obtained: LabEx OSUG - AO International bis 2023, BQR_Isterre
Start date: 01/09/2022
Anticipated thesis defense date: October 2025
ORCID profile: https://orcid.org/0009-0005-1458-2448/
Title: Impact of gold mining on ecosystems and populations in Burkina Faso and Guinea
Summary of your doctoral topic
Over the last ten years, extractive activities have expanded intensively in West Africa, particularly in gold mining regions, due to the rising price of gold. Gold extraction processes and the chemicals used to recover it result in diverse and complex contamination involving contaminants such as mercury (Hg), cyanide (CN) and arsenic (As). The aim of this project is to understand the impact of mining activities on the contamination of surface waters, trophic chains and populations in gold panning camps in Burkina Faso and Guinea, where gold is the main export product. First, we will establish baseline levels of mercury, cyanide and arsenic contamination of waters and food chains in two mining districts. Next, we will identify the sources of pollution, the mechanisms and pathways by which contaminants are transferred to the environment, and those responsible for human exposure. Finally, we will assess the potential impact of these activities on health.
Summary of results:
In Burkina Faso and Guinea, results showed Hg contamination in soils near gold amalgamation sites, with total mercury [THg] in soils reaching 14 µg.g-1 and 16 µg.g- 1 compared to geochemical background of (0.15 ± 0.10 µg.g-1) and (0.46 ± 0.39 µg.g-1 ), respectively, in Burkina Faso and Guinea. The highest levels of Hg contamination were found at large ASGM sites with a long mining history. Thermodesorption experiments indicated that a significant proportion of Hg(0) (35± 13%) was found in soils from ASGM sites in Burkina Faso and (43±21%) in ASGM soils in Guinea, highlighting the significant contribution of Hg(0) redeposited by condensation near amalgam burning sites. The same results show that all mercury is absorbed on particles suspended in water, including 6% dissolved Hg, versus 94% particulate mercury in Burkina Faso, and 1% dissolved Hg versus 99% particulate in Guinea.
Integration of the thesis project into the local, regional and international scientific community:
To offset the disruptions to the biogeochemical cycles of contaminants in the environment (air, water, soil, trophic chains), as well as the health risks generated by these activities, mitigation/rehabilitation and remediation alternatives need to be developed in order to project ourselves into more desirable and sustainable alternative models.
Burkina Faso and Guinea are not isolated cases in the African context, where many countries are affected by the new gold rush linked to the rise in gold prices. My work in this thesis will be pioneering in Burkina Faso and Guinea, where no database on environmental contamination and population exposure to metals and metalloids currently exists.
This work will make it possible to inform government bodies of the deleterious consequences on the environment and the levels of exposure to targeted contaminants induced by these activities, and to target the ecosystem's receptacle compartments, enabling us to propose the development of low-cost remediation systems such as filter gardens.
Outlook for the remainder of the thesis:
Between now and the end of the thesis, I plan to carry out two other projects: the first to spatialize the geochemical data and the second for the epidemiological aspect. This will enable me to understand the consequences of artisanal mining and mercury use on human health. I also intend to take the analysis of mercury speciation a step further by sampling fish in the Niger River and its tributaries, which run through my study area. Based on the initial results, I also plan to study TSS in surface water as well as groundwater, in order to analyze associated heavy metals in addition to mercury in particulate matter. Thanks to the initial results, I intend to write an article on Burkina and Guinea independently of each other. I will then write a comparative article on mercury contamination in these two countries.
Perspective after the end of the thesis:
At the end of my thesis, I plan to work as a teacher-researcher in a university, or in a non-governmental organization. This project is not yet fully defined, but will be by the end of the thesis.