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Jan-Feb 2025
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Spatial assessment of groundwater quality in the watershed draining the city of Manga, Burkina Faso, west Africa
Césard Millogo, Blehiman Sagnon, Abdoul-Azize Barry, And Samuel Nakolendoussé
ABSTRACT: The groundwater in the catchment draining the town of Manga and the surrounding area, which is characteristic of crystalline basement aquifers, undergoes mineral exchange during its residence in the rocks. In addition, factors such as deforestation, human activities and their spatial distribution can influence the chemical composition of groundwater. To date, no geochemical characterisation study by spatial distribution has been carried out in the catchment area of the town of Manga. The main objective of this study was to determine the quality of groundwater and the spatial variations in its physico-chemical parameters. To achieve this, 94 water samples were collected from existing boreholes, stored in bottles, and sent to the laboratory for physicochemical analysis. The analysis results were processed and examined using univariate statistical methods for water quality, whereas kriging and inverse distance weighting (IDW) were employed to assess spatial distribution. The results indicate that the majority of samples exhibit excellent water quality, whereas some areas show elevated concentrations of specific ions, suggesting that the overall groundwater quality in the region remains largely intact. Spatial variations in pH, electrical conductivity, total dissolved solid and ionic strength were observed, with lower values in recharge areas and higher values in discharge zones of the aquifers. NO3- concentrations in excess of WHO standards were not found in boreholes. The highest values were mainly concentrated in the north and north-western part of the study area which are the recharge zone. Spatial analysis revealed areas with moderate spatial dependence, often associated with anthropogenic contamination sources or natural factors such as geogenic mineralization. This study provides a robust framework for understanding the spatial distribution of groundwater quality in the Manga watershed. The results obtained open a promising perspective by suggesting the use of isotopes to accurately map recharge areas and deepen the understanding of infiltration flows in regions with elevated nitrate concentrations.
[ FULL TEXT PDF 1-12 ] DOI: 10.22587/ajbas.2025.19.1.1
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Contribution to the extraction and oil of the physico-chemical characterization of seeds of Ricinus communis L. wild flora of Congo-Brazzaville for the production of the biodiesel
Bertrand Guelor Elongo, Michel Elenga, Arnaud Wenceslas Geoffrey Tamba Sompila, Alfred Raoult Missetété, Christ Dorvy PrivillègeTsaty Nsimba, Dominique Nkounkou Tomodiatounga & Jean Mathurin Nzikou
ABSTRACT: The fall in the use of fossil fuels and the increasing need to safeguard the environment lead to the valorization of alternative sources of energy.Biodiesel is an interesting alternative to the traditional diesel bus; at the same time, it makes it possible to reduce CO2 emissions by 80% and minimize its impact on greenhouse gases and climate change. This work aims to determine the physico-chemical characteristics of the oil of castor seeds (Ricinus communis L.) wild flora of Congo-Brazzaville for the production of the biodiesel. The extraction of oil from castor seeds was made thanks to the method known as Soxhlet, starting with a non-polar organic solvent (hexane) after several cycles of siphonage. After extraction, extracted oil was characterized on parameters such as color, density, viscosity, acid value, acidity, the index of saponification, and pH. The objective of this work is to contribute to the extraction and the physico-chemical characterization of seeds of Ricinus communis L. (Ricin). wild flora of Congo-Brazzaville for the production of the biodiesel. The extraction of oil starting from castor seeds was made thanks to the method known as Soxhlet, starting from a non-polar organic solvent (hexane) after several cycles of siphonage. After extraction, extracted oil was characterized on the parameters such as the color, the density, viscosity, the acid value, acidity, the index of saponification, and the pH. The output of the extraction of oil starting from seeds of Ricinus communis L. of the wild flora of Congo is 33.43%. This extracted oil has a pale yellow color, a density of 0.95 at 25°C, an acidity of 1.69%, and a low kinematic viscosity of 6.16 mm²/s at 28°C. It has a high acid value of 3.28 mg KOH/g when compared with an oil intended for the production of the biodiesel (2 mg KOH/g). Oil obtained is acid with pH = 5, lower than the oil pH intended for the production of the biodiesel to which the value must be close to 7 and rich in fatty acids for long-chain carbonaceous with an index of saponification of 152.40 mg KOH/g. Thus, the utilization of this oil for the production of biodiesel requires the application of a process of cross-esterification upstream.
[ FULL TEXT PDF 13-19 ] DOI: 10.22587/ajbas.2025.19.1.2
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