干旱区生态环境知识资源中心(Arid): Hydrogeochemical and multi-tracer investigations of arsenic-affected aquifers in semi-arid West Africa

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	Hydrogeochemical and multi-tracer investigations of arsenic-affected aquifers in semi-arid West Africa
	Bretzler Anja; Stolze Lucien; Nikiema Julien; Lalanne Franck; Ghadiri Elaheh; Brennwald Matthias S; Rolle Massimo; Schirmer Mario
来源期刊	Geoscience Frontiers
ISSN	1674-9871
出版年	2019
卷号	10 期号:5 页码:1685-1699
英文摘要	The semi-arid Sahel regions of West Africa rely heavily on groundwater from shallow to moderately deep (<100 m b.g.l.) crystalline bedrock aquifers for drinking water production. Groundwater quality may be affected by high geogenic arsenic (As) concentrations (>10 g/L) stemming from the oxidation of sulphide minerals (pyrite, arsenopyrite) in mineralised zones. These aquifers are still little investigated, especially concerning groundwater residence times and the influence of the annual monsoon season on groundwater chemistry. To gain insights on the temporal aspects of As contamination, we have used isotope tracers (noble gases, ~3H, stable water isotopes (~2H, ~(18)PO)) and performed hydrochemical analyses on groundwater abstracted from tube wells and dug wells in a small study area in southwestern Burkina Faso. Results revealed a great variability in groundwater properties (e.g. redox conditions, As concentrations, water level, residence time) over spatial scales of only a few hundred metres, characteristic of the highly heterogeneous fractured underground. Elevated As levels are found in oxic groundwater of circum-neutral pH and show little relation with any of the measured parameters. Arsenic concentrations are relatively stable over the course of the year, with little effect seen by the monsoon. Groundwater residence time does not seem to have an influence on As concentrations, as elevated As can be found both in groundwater with short (<50 a) and long (>10~3 a) residence times as indicated by ~3He/~4He ratios spanning three orders of magnitude. These results support the hypothesis that the proximity to mineralised zones is the most crucial factor controlling As concentrations in the observed redox/pH conditions. The existence of very old water portions with residence times >10~3 years already at depths of <50 m b.g.l. is a new finding for the shallow fractured bedrock aquifers of Burkina Faso, suggesting that overexploitation of these relatively low-yielding aquifers may be an issue in the future.
英文关键词	Arsenic Groundwater chemistry West Africa Fractured aquifers Residence time Noble gases
类型	Article
语种	英语
开放获取类型	DOAJ Gold, Green Published
收录类别	CSCD
WOS研究方向	Mineralogy
CSCD记录号	CSCD:6574154
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/336175
作者单位	Bretzler Anja, Eawag, Swiss Federal Institute of Aquatic Science and Technology;;Centre d'Hydrogeologie et de Geothermie (CHYN), Universite de Neuchatel, ;;, Dubendorf;;, Switzerland;;Switzerland ;;.; Schirmer Mario, Eawag, Swiss Federal Institute of Aquatic Science and Technology;;Centre d'Hydrogeologie et de Geothermie (CHYN), Universite de Neuchatel, ;;, Dubendorf;;, Switzerland;;Switzerland ;;.; Stolze Lucien, Technical University of Denmark (DTU), Lyngby, Denmark.; Rolle Massimo, Technical University of Denmark (DTU), Lyngby, Denmark.; Nikiema Julien, Universite Ouaga I Pr. Joseph KI-ZERBO, Ouagadougou, Burkina Faso.; Lalanne Franck, Institut International d'lngenierie de l'Eau et de I'Environnement (2iE), Ouagadougou, Burkina Faso.; Ghadiri Elaheh, Eawag, Swiss Federal Institute of Aquatic Science and Technology;;ETH Zurich, Department of Environmental System Sciences, ;;, Dubendorf;;Ziirich, Switzerland;;Switzerland ;;.; Brennwald Matthias S, Eawag, Swiss Federal Institute of Aquatic Science and Te...
推荐引用方式 GB/T 7714	Bretzler Anja,Stolze Lucien,Nikiema Julien,et al. Hydrogeochemical and multi-tracer investigations of arsenic-affected aquifers in semi-arid West Africa[J],2019,10(5):1685-1699.
APA	Bretzler Anja.,Stolze Lucien.,Nikiema Julien.,Lalanne Franck.,Ghadiri Elaheh.,...&Schirmer Mario.(2019).Hydrogeochemical and multi-tracer investigations of arsenic-affected aquifers in semi-arid West Africa.Geoscience Frontiers,10(5),1685-1699.
MLA	Bretzler Anja,et al."Hydrogeochemical and multi-tracer investigations of arsenic-affected aquifers in semi-arid West Africa".Geoscience Frontiers 10.5(2019):1685-1699.