[ Origines des Nitrates dans les Aquifères Discontinus du Socle du Damagaram Mounio, Est du Niger ]
Volume 38, Issue 4, February 2023, Pages 839–846
Abdou Hamidou1, Ibrahim Adédé2, and Issa Habou3
1 Université André Salifou (UAS), Faculté des Sciences et Techniques (FST), Département de Géosciences et Environnement, Zinder, Niger
2 Direction Régionale de l’Hydraulique et de l’Assainissement de Zinder (DRHA, Z). Laboratoire de chimies des eaux de la Direction Régionale de l’Hydraulique et de l’Assainissement, Zinder, Niger
3 Direction Régionale de l’Hydraulique et de l’Assainissement de Zinder (DRHA, Z). Laboratoire de chimies des eaux de la Direction Régionale de l’Hydraulique et de l’Assainissement, Zinder, Niger
Original language: French
Copyright © 2023 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The base of Damagaram Mounio, study area, outcrops in the eastern part of the Zinder region. In this zone, discontinuous aquifers are located in fractured, fissured and/or altered horizons of Precambrian granitoid and metamorphic formations and young fissured granites. They are essentially captured by fodder whose very high failure rates can exceed 50%. In addition, the flow rates of positive fodder are less than 2 m3/h for more than 85% of them. Thus, the problem of water resources is acute. In this densely populated area, this lack of water for the population’s food is aggravated by the levels of certain chemical parameters, including nitrates in particular, which greatly exceed the drinking water standards for human consumption, hence the present study. the main objective of which is to determine the origins of nitrates in the groundwater resources of the area. The methodological approach based on the sampling of hydraulic structures capturing the aquifers of the basement, the analysis of the physico-chemical and isotopic parameters of the waters of several boreholes, the determination characteristics of nitrates, led to several interesting results. Thus, the isotopic contents of Nitrogen 15 (15N), obtained in the groundwater of the area, varying from 0 to 7.2, thus showing that these nitrates could come from the nature of the soil (quagmire around the points) and chemical fertilizers, ureas and fertilizers used in the study area. This study has shown that in the basement area of Damagaram Mounio, nitrates have a superficial origin. The nitrate contents of the waters of the Damagaram Mounio basement aquifers vary from 0.22 to 313.3 mg/L, with an average of 72.23 mg/L, and a standard deviation of 62.23. Thus, 32% of the modern structures sampled have nitrate levels above the acceptable limit value for drinking water set at 50 mg/L, according to the standards of the World Health Organization (WHO); these waters are unfit for human consumption. The spatial distribution of nitrate levels in groundwater in the area showed that these are more accentuated between the towns of Damagaram Takaya and Birni Kazoé, which are characterized by values above 100 mg/l. Furthermore, the relationship between nitrate levels and electrical conductivity values of water showed that the mineralization of groundwater in the area is controlled by nitrate ions.
Author Keywords: Discontinuous aquifer, WHO, Nitrates, Damagaram Mounio.
Volume 38, Issue 4, February 2023, Pages 839–846
Abdou Hamidou1, Ibrahim Adédé2, and Issa Habou3
1 Université André Salifou (UAS), Faculté des Sciences et Techniques (FST), Département de Géosciences et Environnement, Zinder, Niger
2 Direction Régionale de l’Hydraulique et de l’Assainissement de Zinder (DRHA, Z). Laboratoire de chimies des eaux de la Direction Régionale de l’Hydraulique et de l’Assainissement, Zinder, Niger
3 Direction Régionale de l’Hydraulique et de l’Assainissement de Zinder (DRHA, Z). Laboratoire de chimies des eaux de la Direction Régionale de l’Hydraulique et de l’Assainissement, Zinder, Niger
Original language: French
Copyright © 2023 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The base of Damagaram Mounio, study area, outcrops in the eastern part of the Zinder region. In this zone, discontinuous aquifers are located in fractured, fissured and/or altered horizons of Precambrian granitoid and metamorphic formations and young fissured granites. They are essentially captured by fodder whose very high failure rates can exceed 50%. In addition, the flow rates of positive fodder are less than 2 m3/h for more than 85% of them. Thus, the problem of water resources is acute. In this densely populated area, this lack of water for the population’s food is aggravated by the levels of certain chemical parameters, including nitrates in particular, which greatly exceed the drinking water standards for human consumption, hence the present study. the main objective of which is to determine the origins of nitrates in the groundwater resources of the area. The methodological approach based on the sampling of hydraulic structures capturing the aquifers of the basement, the analysis of the physico-chemical and isotopic parameters of the waters of several boreholes, the determination characteristics of nitrates, led to several interesting results. Thus, the isotopic contents of Nitrogen 15 (15N), obtained in the groundwater of the area, varying from 0 to 7.2, thus showing that these nitrates could come from the nature of the soil (quagmire around the points) and chemical fertilizers, ureas and fertilizers used in the study area. This study has shown that in the basement area of Damagaram Mounio, nitrates have a superficial origin. The nitrate contents of the waters of the Damagaram Mounio basement aquifers vary from 0.22 to 313.3 mg/L, with an average of 72.23 mg/L, and a standard deviation of 62.23. Thus, 32% of the modern structures sampled have nitrate levels above the acceptable limit value for drinking water set at 50 mg/L, according to the standards of the World Health Organization (WHO); these waters are unfit for human consumption. The spatial distribution of nitrate levels in groundwater in the area showed that these are more accentuated between the towns of Damagaram Takaya and Birni Kazoé, which are characterized by values above 100 mg/l. Furthermore, the relationship between nitrate levels and electrical conductivity values of water showed that the mineralization of groundwater in the area is controlled by nitrate ions.
Author Keywords: Discontinuous aquifer, WHO, Nitrates, Damagaram Mounio.
Abstract: (french)
Le socle du Damagaram Mounio, zone d’étude, affleure dans la partie Est de la région de Zinder. Dans cette zone, les aquifères discontinus sont localisés dans des horizons fracturés, fissurés et/ou altérés des formations granitoïdiques et métamorphiques du Précambrien et des granites jeunes fissurés. Ils sont captés essentiellement par des forages dont les taux d’échec, très élevés, peuvent dépasser les 50%. Par ailleurs, les débits des forages positifs sont inférieurs à 2 m3/h à plus de 85% d’entre eux. Ainsi, le problème de ressource en eaux se pose avec acuité. Dans cette zone très peuplée, ce manque d’eau pour l’alimentation des populations est aggravé par les teneurs des certains paramètres chimiques, dont notamment les nitrates, dépassant largement les normes de potabilité des eaux pour la consommation humaine d’où la présente étude, qui a pour objectif principal, la détermination des origines des nitrates dans les ressources en eau souterraine de la zone. L’approche méthodologique basée sur l’échantillonnage des ouvrages hydrauliques captant les aquifères du socle, l’analyse des paramètres physico chimiques et isotopiques des eaux de plusieurs forages, la détermination des caractéristiques des nitrates, a permis d’aboutir à plusieurs résultats intéressants. Ainsi, les teneurs isotopiques en Azote 15 (15N), obtenues dans les eaux souterraines de la zone, varient de 0 à 7,2, montrant ainsi que ces nitrates pourraient provenir de la nature du sol (bourbier autour des points) et engrais chimiques, urées et fertilisants utilisées dans la zone d’étude. Cette étude, a permis de montrer que dans la zone du socle du Damagaram Mounio, les nitrates ont une origine superficielle. Les teneurs en nitrates des eaux des nappes du socle de Damagaram Mounio, varient de 0,22 à 313,3 mg/L, avec une moyenne de 72,23 mg/L, et un écart type de 62,23. Ainsi, 32% des ouvrages modernes échantillonnés, ont de teneurs en nitrates supérieures à la valeur limite admissible pour les eaux de consommation fixés à 50 mg/L, selon les normes de l’Organisation Mondiale de la Santé (OMS); ces eaux sont inaptes à la consommation humaine. La distribution spatiale des teneurs en nitrates dans les eaux souterraines de la zone, a montré que celles-ci sont plus accentuées entre les villes de Damagaram Takaya et Birni Kazoé, qui se caractérisent par de valeurs supérieures à 100 mg/l. Par ailleurs, la relation entre les teneurs en nitrates et les valeurs de conductivités électriques des eaux, a montré que la minéralisation des eaux souterraines de la zone, est contrôlée par les ions nitrates.
Author Keywords: Aquifère discontinu, OMS, Nitrates, Damagaram Mounio.
How to Cite this Article
Abdou Hamidou, Ibrahim Adédé, and Issa Habou, “Origins of Nitrates in the Discontinuous Aquifers of the Damagaram Mounio Basement, Eastern Niger,” International Journal of Innovation and Applied Studies, vol. 38, no. 4, pp. 839–846, February 2023.
