干旱区生态环境知识资源中心(Arid): The origin of high salinity and hydrogeochemical characteristics of groundwater in semi-arid area of the Linta Basin, Southwestern Madagascar

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DOI	10.1016/j.jafrearsci.2024.105215
	The origin of high salinity and hydrogeochemical characteristics of groundwater in semi-arid area of the Linta Basin, Southwestern Madagascar
	Rafenoarisoa, Onja Eric Mario; Sracek, Ondra; Rahobisoa, Jean -Jacques; Cejkova, Bohuslava; Jackov, Ivana; Brouyere, Serge
通讯作者	Rafenoarisoa, OEM
来源期刊	JOURNAL OF AFRICAN EARTH SCIENCES
ISSN	1464-343X
EISSN	1879-1956
出版年	2024
卷号	213
英文摘要	The Linta Basin, located in the Southwestern Madagascar, is a semi-arid area where groundwater in fractured media bedrock aquifer constitutes the main source of water supply. In the last two decades, highly mineralized groundwater was identified in this area; however, the origin of the salinity was not clear. The purpose of the study was to clarify the origin of salinity and to identify hotspots with groundwater unsuitable for water supply. Groundwater quality in this basin was investigated by hydrogeochemical and isotopic methods accompanied by mineralogical study. In total, 32 groundwater samples were collected and analyzed. The results showed that groundwater temperature varied from 25.2 degrees C to 31.7 degrees C. Values of pH and TDS varied from 6.55 to 8.24 and 221 to 5612 mg/L, respectively. The aquifer, which is mainly fractured, showed 7 groundwater types, namely Mg-HCO3, Na-HCO3 and also Na-Cl, Mg-Cl, Na-Cl-HCO3, Mg-Cl-HCO3- , and Ca-Mg-HCO3. Two groups of variables have been identified by factor analysis; the factor F1 comprises EC, Ca2+, Mg2+, SO42- , and Cl- whereas the factor F2 comprises HCO3-, K+, and Na+, and they were interpreted in terms of hydrogeochemical processes. Values of saturation indices (SI) for carbonate minerals were generally positive, indicating their possible precipitation. Based on the Gibbs diagram and factor analysis, groundwater mineralization is affected by water-rock interactions and evaporation, respectively. The important role of evaporation is confirmed by enrichment of stable isotopes with delta O-18 values up to 1.2 parts per thousand. Processes such as base ionic exchange process and reverse ionic exchange process may also be important locally. The main origin of groundwater mineralization is the hydrolysis of silicate minerals such as feldspars and micas coupled with evaporation. In several wells, salinity is too high for water supply and nitrate concentration is above the WHO limit for drinking water. Results of the study highlighted groundwater chemistry formation processes and are applicable in other African countries with bedrock aquifers.
英文关键词	Linta basin Madagascar Silicate hydrolysis Evaporation Cation exchange
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:001216294700001
WOS关键词	BASEMENT AQUIFERS ; EVOLUTION ; QUALITY ; NORTHERN ; RECHARGE ; TECTONICS ; REGION
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/404317
推荐引用方式 GB/T 7714	Rafenoarisoa, Onja Eric Mario,Sracek, Ondra,Rahobisoa, Jean -Jacques,et al. The origin of high salinity and hydrogeochemical characteristics of groundwater in semi-arid area of the Linta Basin, Southwestern Madagascar[J],2024,213.
APA	Rafenoarisoa, Onja Eric Mario,Sracek, Ondra,Rahobisoa, Jean -Jacques,Cejkova, Bohuslava,Jackov, Ivana,&Brouyere, Serge.(2024).The origin of high salinity and hydrogeochemical characteristics of groundwater in semi-arid area of the Linta Basin, Southwestern Madagascar.JOURNAL OF AFRICAN EARTH SCIENCES,213.
MLA	Rafenoarisoa, Onja Eric Mario,et al."The origin of high salinity and hydrogeochemical characteristics of groundwater in semi-arid area of the Linta Basin, Southwestern Madagascar".JOURNAL OF AFRICAN EARTH SCIENCES 213(2024).