Exemple d’impacts de l’arrêt de l’exploitation minière et de l’exhaure dans le bassin houiller de Faulquemont (Lorraine)

L’ensemble du volume des terrains affectés par une exploitation minière souterraine peut être considéré comme un réservoir aquifère qui, contrairement à un aquifère classique, n’est pas matérialisé par des limites physiques bien définies. Il correspond en effet au volume des vides dus à la fracturation naturelle et celle induite par l’exploitation, à la porosité matricielle du massif, ainsi qu’au volume des vides miniers résiduels. Cette communication présente en premier lieu les résultats de deux méthodes d’évaluation des vides miniers résiduels appliquées à l’étude du bassin de Faulquemont et les compare au volume d’eau nécessaire à l’ennoyage de ce bassin. La deuxième partie de cette communication s’intéresse aux éventuels effets sur la stabilité des terrains de surface de la remontée des eaux dans ce même bassin. En effet, des études menées concernant respectivement aux Pays-Bas, en Allemagne et, plus récemment, en France ont mis clairement en évidence que la remontée des eaux après l’arrêt de l’exhaure minière peut générer un soulèvement des terrains. Les observations faites en Lorraine dans le secteur de Faulquemont, où la remontée des eaux est stabilisée, donnent des résultats similaires. Aucune conséquence sur le bâti et les infrastructures n’a été constatée jusqu’à présent dans les bassins miniers soumis à ce phénomène

Anthropic impacts on Sub-Saharan urban water resources through their pharmaceutical contamination (Yaounde, Center Region, Cameroon)

Sub-Saharan urban centers have to tackle high population growth, lack of sanitation infrastructures and the need for good quality water resources. To characterize the impacts of anthropization on the water resources of the capital of Cameroon (Yaounde), a multi-disciplinary approach was used in ten sub-watersheds (peri-urban and urban) of the Mefou watershed. Pharmaceutical residues were used as tracers of surface and groundwater contamination caused by the release of domestic wastewater from pit latrines and landfills. A water use survey was conducted in the vicinity of the sampling sites to better assess water use, treatment and management. Available land use and hydro-geomorphological data completed characterization of the sub-watersheds. The combined data showed that natural features (elevation, slope, and hydrography) and human activities (land use) favor rainfall-runoff events and hence surface water contamination. Pharmaceutical monitoring revealed contamination of both surface and groundwater especially in the urban sub-watersheds. Analgesics/anti-inflammatory drugs and anti-epileptic carbamazepine were the most frequently found compounds (in up to 91% of water samples) with concentrations of acetaminophen reaching 5660 ng/L. In urban sub-watersheds, 50% of the groundwater sites used for drinking water were contaminated by diclofenac (476-518 ng/L), carbamazepine (263-335 ng/L), ibuprofen (141-276 ng/L), sulfamethoxazole (<2-1285 ng/L) and acetaminophen (110-111 ng/L), emphasizing the need for a deeper understanding of the interactions between surface and groundwater. The use of groundwater as drinking water by 68% of the total population surveyed raises concerns about population exposure and potential health risks. This case study highlights the need for strategies to limit contamination of the water resource given the predicted future expansion of Sub-Saharan urban centers

Anthropic impacts on Sub-Saharan urban water resources through their pharmaceutical contamination (Yaoundé, Center Region, Cameroon)

(IF 6.55; Q1)International audienceSub-Saharan urban centers have to tackle high population growth, lack of sanitation infrastructures and the need for good quality water resources. To characterize the impacts of anthropization on the water resources of the capital of Cameroon (Yaoundé), a multi-disciplinary approach was used in ten sub-watersheds (peri-urban and urban) of the Méfou watershed. Pharmaceutical residues were used as tracers of surface and groundwater contamination caused by the release of domestic wastewater from pit latrines and landfills. A water use survey was conducted in the vicinity of the sampling sites to better assess water use, treatment and management. Available land use and hydro-geomorphological data completed characterization of the sub-watersheds. The combined data showed that natural features (elevation, slope, and hydrography) and human activities (land use) favor rainfall-runoff events and hence surface water contamination. Pharmaceutical monitoring revealed contamination of both surface and groundwater especially in the urban sub-watersheds. Analgesics/anti-inflammatory drugs and anti-epileptic carbamazepine were the most frequently found compounds (in up to 91% of water samples) with concentrations of acetaminophen reaching 5660 ng/L. In urban sub-watersheds, 50% of the groundwater sites used for drinking water were contaminated by diclofenac (476–518 ng/L), carbamazepine (263–335 ng/L), ibuprofen (141–276 ng/L), sulfamethoxazole (<2–1285 ng/L) and acetaminophen (110–111 ng/L), emphasizing the need for a deeper understanding of the interactions between surface and groundwater. The use of groundwater as drinking water by 68% of the total population surveyed raises concerns about population exposure and potential health risks. This case study highlights the need for strategies to limit contamination of the water resource given the predicted future expansion of Sub-Saharan urban centers