Interpretation of undisturbed hydrogeochemical conditions in Neogene sediments of the Horonobe area, Hokkaido, Japan

Evaluation of Water Resources Quality in Sabodala Gold Mining Region and Its Surrounding Area (Senegal)

“…Multivariate geostatistical analysis by PCA showed two main sources of water mineralization for the major elements. A first natural source characterized by Ca-Mg-HCO 3 and Na-HCO 3 types observed at boreholes and unpolluted surface waters and a second anthropogenic source related to their high nitrates contents mainly observed in village wells that tap the upper weathered aquifers. Granites GW are less mineralized and are enriched in alkali (Na + K), while schistes and volcano-sediments GW and mafic volcanic GW more mineralized, are characterized by higher contents of alkaline earth (Ca + Mg).…”

“…Results indicate that, at eastern Senegal the upper weathered aquifers are highly vulnerable to pollution as shown by well waters often affected by pollution related human activities observed in gold mining areas. Therefore, consumption in long term of these contaminated well waters could cause health effects to population that is exposed to these relatively high NO 3 and trace element concentrations especially at Sabodala village where, further investigations should be conducted in order to better manage monitoring and assessment of drinking-water quality in community supplies.…”

“…However, different Ca/Na ratio to that of plagioclase found in the weathered aquifer implies other sources of Ca or a sink of Na [18]. Therefore, water chemistry in upper weathered aquifers evolves very differently, and can be also affected by organic pollution marked by high concentrations of 3 …”

“…Groundwaters in Granite setting exhibit the lowest median value (185 μS·Cm −1 ), followed groundwater sampled in mafic volcanic terrain (213 μS·Cm −1 ) and those from schistes and volcano-sediments which median value is the highest (351 μS·Cm −1 ). However it should be noted that the maximum EC was recorded at Bembou well (790 µS·cm −1 ) tapping the granite rock; this high value is likely to be induced by organic pollution marked by high 3 …”

“…This study is aimed to determine water resources quality in relation to the geological nature birimian terrains as well as anthropogenic activities impact related to both industrial and traditional gold mining. The methodological approach based on use of geostatistical tools [3] [4] by PCA (principal components analysis) was conducted on various chemical and physico-chemical parameters in order to discriminate: water chemistry depending on geology of different aquifer types (granites, mafic volcanic rocks, shistes and volcano-sediment) and further anthropogenic inputs induced by mining activities in the sector. Hierarchical cluster analysis (HCA) and the Ward jump, as well as a representation of classes by the biplot function have been used to identify water classes that have enabled to determine the various changes in the chemical water composition that could compromise their quality for human consumption.…”