The Influence of Karst Aquifer Mineralogy And
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water Article The Influence of Karst Aquifer Mineralogy and Geochemistry on Groundwater Characteristics: West Bank, Palestine Hassan Jebreen 1,* , Andre Banning 1 , Stefan Wohnlich 1, Andrea Niedermayr 1, Marwan Ghanem 2 and Frank Wisotzky 1 1 Hydrogeology Department, Institute of Geology, Geophysics and Mineralogy, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; [email protected] (A.B.); [email protected] (S.W.); [email protected] (A.N.); [email protected] (F.W.) 2 Department of Geography, Birzeit University, P.O. Box 14, Ramallah, Palestine; [email protected] * Correspondence: [email protected]; Tel.: +49-234-322-5387 Received: 31 October 2018; Accepted: 7 December 2018; Published: 11 December 2018 Abstract: This work reports, for the first time, the mineralogical and geochemical characteristics of karst aquifers in the Central West Bank (CWB) catchment in Palestine. It provides an integrated study approach by correlating the geochemistry of the lithology and hydrochemical data of groundwater samples. Mineralogical analysis showed that all of the samples were dominantly composed of either calcite CaCO3 (5–100 wt. %) or dolomite CaMg(CO3)2 (4–100 wt. %), with minor amounts of quartz and feldspar, which is supported by the inorganic carbon content (9–13 wt. %) and hydrochemical composition of the spring water samples. The whole-rock geochemical data indicated that the samples have low contents of trace elements and transition metals. In contrast, the concentrations of alkaline earth elements (Mg, Ca, Sr, Ba) and Mn were high in the rock and groundwater samples. Generally, the trace elements of rock samples with concentrations >10 ppm included Sr (17–330 ppm), Mn (17–367 ppm), Ba (2–32 ppm), W (5–37 ppm), Cr (3–23 ppm), Zn (1.7–28 ppm), V (4–23 ppm), and Zr (1–22 ppm), while the concentrations of all the other trace elements was below 10 ppm. Ionic ratios and hierarchical cluster analysis (HCA) suggested that the chemical evolution of groundwater was mainly related to the geogenic (rock–water) interaction in the study area. This is clear in the alkaline earth elements (Mg, Ca, Sr, Ba) ratios, especially regarding the Sr values. The calcite rock samples had higher Sr (mean 160 ppm, n = 11) than those of the dolomite rocks (mean 76 ppm, n = 9). Keywords: karst aquifer; mineralogy; geochemistry; groundwater; sediments; West Bank 1. Introduction The nature and composition of the bedrock is the main control of regional groundwater mineralization. The hydrogeochemical signatures of groundwater resources are chiefly influenced by the characteristics of their catchment area. Several factors such as the climatic conditions, bedrock geology, soil properties, and anthropogenic activities influence water flow and its overall quality status [1]. The structure of karst systems is complex, and the related functioning mechanism of aquifers can be highly heterogeneous [2]. Knowledge of the properties of these karst rocks is increasingly important for the effective management of groundwater reserves and an understanding of the properties that influence a range of geotechnical issues [3]. The hydrogeochemistry of carbonate aquifers is determined by several complex processes; the most important is the dissolution and precipitation of minerals, the infiltration of surface water, biogeochemical processes, and water–rock interactions such as cation exchange, which all change the composition of groundwater [4]. Water 2018, 10, 1829; doi:10.3390/w10121829 www.mdpi.com/journal/water Water 2018, 10, 1829 2 of 18 Water 2018, 10, x FOR PEER REVIEW 2 of 20 The essential groundwater in West Bank is usually found in karstified limestone and dolomite aquiferThe systems. essential For groundwater sustainable in groundwaterWest Bank is usually management found in in karstified West Bank limestone aquifers, and dolomite knowledge regardingaquifer thesystems. influences For ofsustainable the geological groundwater structure management and the karst in system West Bank on groundwater aquifers, knowledge composition is required.regarding As the such, influences the western of the aquifer geological is one ofstructure the main and reserves the karst of fresh system water on in groundwater West Bank. composition is required. As such, the western aquifer is one of the main reserves of fresh water in As in all karst regions, these aquifers are particularly vulnerable to pollution (see, for example, [5,6]). West Bank. To date, the region has been studied mainly for its hydrochemistry [4,7,8]; its hydrogeology and geology As in all karst regions, these aquifers are particularly vulnerable to pollution (see, for example, have also been investigated [9–11]. Although the recharge and flow systems were investigated [12–19], [5,6]). To date, the region has been studied mainly for its hydrochemistry [4,7,8]; its hydrogeology no detailedand geology mineralogical have also been and investigated geochemical [9 study–11]. Although to investigate the recharge the composition and flow systems and geological were evolutioninvestigated of the [12 sediments–19], no detailed has been mineralogical carried out. and The geochemical current study study characterizes to investigate for the the comp firstosition time the elementaland geological composition evolution (including of the sediments rare earth has elements) been carried and mineralogyout. The current of sediments study characterizes in Central for West Bankthe (CWB). first time the elemental composition (including rare earth elements) and mineralogy of sediments inThe Central aims West of this Bank paper (CWB). are to investigate the mineralogy and geochemistry of karst aquifers in Central WestThe aims Bank, of clarifythis pa theper geologicalare to investigate control the on groundwatermineralogy and quality geochemistry in order of to karst identify aquifers the natural in weatheringCentral West processes Bank, within clarify the the catchment, geological andcontrol establish on groundwater a link between quality groundwater in order tohydrochemistry identify the andnatural geological weathering materials. processes For this within purpose, the catchment, rock and and spring establish water a samples link between collected groundwater in the study areahydrochemistry were analyzed and for geological their concentration materials. For of majorthis purpose, ions, trace rock elements,and spring rarewater earth samples elements collected (REE), inorganicin the carbonstudy area content, were andanaly X-rayzed for diffraction their concentration patterns. of major ions, trace elements, rare earth elements (REE), inorganic carbon content, and X-ray diffraction patterns. 2. Materials and Methods 2. Materials and Methods 2.1. Study Site Description 2.1. Study Site Description Our study area is located in the CWB, Palestine. The larger part of the study area is located within Our study area is located in the CWB, Palestine. The larger part of the study area is located the Western Aquifer Basin (WAB), which is the largest shared groundwater aquifer between Israel and within the Western Aquifer Basin (WAB), which is the largest shared groundwater aquifer between West Bank; the other part is located in the Eastern Aquifer Basin (EAB) (Figure1). The study area lies Israel ◦and0 West Bank◦ 0; the other part is located◦ 0 in the◦ Eastern0 Aquifer Basin (EAB) (Figure 1). The2 withinstudy 35 area00 andlies within 35 15 35°00longitude′ and 35°15 and′ 31 longitude80 and and 32 31°8010 latitude,′ and 32°10 which′ latitude, covers which about covers 917 km about. 917 km2. 35°0’0"E International boundary Lake Tiberias Groundwater boundary River Lake and sea Study Area Northeastern a e Aquifer S Basin n r N a e e West Bank v J n i a r R o N N r R " " e E n 0 0 ’ ’ t r i F a 0 0 I ° ° d d 2 2 U r 3 3 e Eastern d Q o M A Aquifer J a L Basin A T n S A Jerusalem O Western C Aquifer Basin Dead Gaza Strip Sea Egypt 35°0’0"E FigureFigure 1. 1. LocationLocation of the the study study area. area. Water 2018, 10, 1829 3 of 18 GeologicalWater 2018 and, 10 Hydrogeological, x FOR PEER REVIEW Setting 3 of 20 ClimateGeological in and the Hydrogeological recharge area is Setting Mediterranean and semi-arid with an average precipitation of 550–700 mm/yearClimate in overthe recharge the winter area [ 20is ].Mediterranean Over 70% of and the semi annual-arid rainfallwith an occursaverage between precipitation December of and February.550–700 mm/year The study over area the winter is located [20]. Over within 70% the of rechargethe annual area rainfall of theoccurs fractured between carbonate December Westernand MountainFebruary. aquifer The (Yarkon–Taninim).study area is located This within is a the fresh recharge water aquiferarea of the mainly fractured used carbonate for the production Western of drinkingMountain water. aquifer The estimated (Yarkon– rechargeTaninim). rangesThis is a between fresh water 111–211 aquifer mm/year, mainly used representing for the production 19% to 37%of of the long-termdrinking meanwater. annualThe estimated rainfall. rec Inharge addition, ranges the between mean 111 annual–211 mm/year, actual evapotranspiration representing 19% to was 37% about 66–70%of the of precipitationlong-term mean [12 annual]. The rainfall. topographic In addition, gradient the mean from theannual mountain actual evapotranspiration range (highest elevation: was about 66–70% of precipitation [12]. The topographic gradient from the mountain range (highest 975 m.a.s.l.) in the eastern edge of the catchment in Ramallah Mountains descends drastically to about elevation: 975 m.a.s.l.) in the eastern edge of the catchment in Ramallah Mountains descends 0.1 mdrastically a.s.l. in the to westabout at 0.1 the m a.s.l. confluence in the west with at thethe confluence coastal aquifer. with the The coastal local aquifer. geology The of local the study geology area is composedof the ofstudy karstic area and is composed permeable of karstic limestones and permeable and dolomites limestones with and much dolomites smaller with amounts much ofsmaller marl and chalkamounts interbedded of marl with and argillaceous chalk interbedded beds of with late Albian–Turonianargillaceous beds of age late [21 Albian] (Figure–Turonian2).