ASSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN HIDROGEOKEMIČNA IN IZOTOPSKA KARAKTERIZACIJA TER OCENA HIDRAVLIČNEGA DELOVANJA KOMPLEKSNEGA KRAŠKEGA OBMOČJA IZEH, PROVINCA KHUZESTAN, JUGOZAHODNI IRAN Nasrollah KALANTARI1*, Zahra SAJADI2, Abbas CHARCHI3 & Seyyed Sajedin MOUSAVI4 Abstract UDC 550.42:532.5:556(55) Nasrollah Kalantari, Zahra Sajadi, Abbas Charchi & Sayyed Sajedin Mousavi: Assessment of the hydrogeochemical and isotopic characterization and hydraulic behavior of the Izeh complex karstic area, Khuzestan province, southwest Iran Proper water resources management requires recognizing and evaluating the factors that affect the quantity and quality of wa- ter resources. The Ilam-Sarvak (Upper Cretaceous) and Asmari (Oligocene to Miocene) limestone- dolomite formations in the Zagros structural belt have formed a promising karst ground- water horizon. In the present study, the hydraulic relationship between the karst structures of the Izeh territory in the north- east of Khuzestan province was investigated using hydrogeo- chemical and isotopic information of springs and wells. The results enabled to understand various components influencing the recharge of water resources. In this study, samples were col- lected from the karst springs and wells of Mongasht, Shavish- Tanosh and Kamarderaz anticlines and Naal-e-Asbi (Horse- shoe) syncline and meteoric water to understand the hydro- chemical and isotopic characterization, and hydrogeological and hydraulic behavior of the Izeh karst system. The meteoric and groundwater samples were analyzed to determine major and minor ion concentrations and δ18O and δ2H isotope ratios. Isotopic content ranged from -31.6 to -2.9‰ and from -6.32 to -1.87‰ for δ2H and δ18O, respectively, and d-excess values were high and positive. The study of the isotopic content of water Izvleček UDK 550.42:532.5:556(55) Nasrollah Kalantari, Zahra Sajadi, Abbas Charchi & Sayyed Sajedin Mousavi: Hidrogeokemična in izotopska karakteriza- cija ter ocena hidravličnega delovanja kompleksnega kraške- ga območja Izeh, provinca Khuzestan, jugozahodni Iran Ustrezno gospodarjenje z vodnimi viri temelji na prepoznava- nju in vrednotenju dejavnikov, ki vplivajo na količino in kako- vost vodnih virov. Apnenčasto-dolomitni formaciji Ilam-Sarvak (zgornja kreda) in Asmari (oligocen do miocen) v strukturnem pasu Zagros sta oblikovali obetaven kraški vodonosnik. V tej študiji je bil hidravlični odnos med kraškimi strukturami oze- mlja Izeh, ki je na severovzhodu province Khuzestan, ocenjen z uporabo hidrogeokemičnih in izotopskih analiz vode v izvirih in vodnjakih. Rezultati so omogočili razumevanje komponent, ki vplivajo na napajanje vodnih virov. Zbrani so bili vzorci iz kraških izvirov in vodnjakov antiklinal Mongašt, Šaviš-Tanoš, Kamarderaz, sinklinale Naal-e-Asbi (podkev) in meteorne vode, da bi razumeli hidrokemično in izotopsko karakterizacijo ter hi- drogeološko in hidravlično delovanje kraškega sistema Izeh. Za določitev koncentracij glavnih in drugotnih ionov ter razmerja izotopov δ18O in δ2H so bili analizirani vzorci meteorne in pod- zemne vode. Vsebnosti izotopov so bile v razponu od ‒31,6 do ‒2,9 ‰ za δ2H in od ‒6,32 do ‒1,87 ‰ za δ18O, vrednosti devteri- jevega presežka pa so bile visoke in pozitivne. Analize vsebnosti izotopov v vzorcih vode iz izvirov in vodnjakov v regiji kažejo na tri skupine vodnih virov. Prva skupina, ki je povezana z izviri ACTA CARSOLOGICA 52/1, 67-92, POSTOJNA 2023 1 Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Iran, e-mail: nkalantari@hotmail.com, n.kalantari@scu.ac.ir 2 Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Iran, e-mail: sajadi_z@yahoo.com 3 Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Iran, e-mail: charchi38@scu.ac.ir 4 Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Iran, e-mail: s.mousavi@scu.ac.ir * Corresponding author Prejeto/Received: 24.2.2022 DOI: https://doi.org/10.3986/ac.v52i1.10687 1. INTRODUCTION For groundwater supply to be managed sustainably in water scarce regions, understanding the sources of re- charge and flow pattern of groundwater in these regions is imperative. The hydrochemical and stable isotope techniques have been commonly employed to iden- tify groundwater recharge mechanisms and flow paths (Scanlon et al., 2002; Gates et al., 2008; Slabe & Liu, 2009; Bourke et al., 2015; Connor et al., 2017; Chen et al., 2018; Morsy et al., 2018; Mokadem et al., 2021). Dur- ing the last three decades, chemical constituents and the isotopic composition of water have been widely used to characterize the groundwater recharge sources, recharge rate and flow pattern and therefore address associated re- source problems (Bajjali, 2006; Edmunds et al., 2006; Ma et al., 2013). Karst regions have a specific hydrogeological char- acter (Milanovic, 1981; Ford & Williams, 1989, 2007) be- cause the constituent rocks, like limestone and dolomite, are highly susceptible to chemical dissolution (Milanovic, 1981; Goldscheider & Andreo, 2007). In the karstic re- gions, the study of chemistry is essential (White, 2015) be- cause hydrochemical properties reflect the mechanism of groundwater flow in karstic rocks. Karst aquifers have het- erogeneous characteristics owing to the three media-based systems through which groundwater flows, namely pores, fractures, and cavities (Goldscheider & Andreo, 2007). The chemical constituents of groundwater illus- trate a key role in evaluating the quality of water. In unpolluted groundwater systems, major and minor ions composition is controlled by several factors like geol- ogy, water-rock interaction and recharge water (Kri- enen et al., 2017; Pracny et al., 2017; Jebreen et al., 2018; Ventura-Houle et al., 2021). As it is known, water con- tains dissolved ions that affect the physical and chemi- cal properties of water. Therefore, scientists continue to investigate the physical and chemical properties of groundwater (Wang et al., 2018; Rehman et al., 2019; Farid et al., 2020; Haldar et al., 2020; Yasin & Kargın, 2021). Studies of karst hydrogeological systems using hydrochemical and stable isotope analyses (18O and 2H) have been conducted by Ashjari and Raeisi (2006), Dimitriou and Tsintza (2015), Alemayehu et al. (2020), Setiawan et al. (2020) while the more specific study em- ploying multivariate hydrochemical analysis has also been conducted by e.g., Valdes et al. (2007); Narany et al. (2014); Chihi et al. (2015) and Yuan et al. (2017). These studies generally explain hydrochemical process- es such as dissolution and precipitation of carbonate minerals, and identification of karstic hydrogeological systems, including; the process of karst groundwater re- charge, flow pattern, and discharge. The isotopes 18O and 2H are conservative (Tillman et KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN antiklinale Mongašt, ima nižje izotopske vrednosti, kar kaže, da se napaja s padavinami na višjih nadmorskih višinah in s talje- njem snega. Izotopska vrednost druge skupine je bogatejša od prve skupine, kar kaže na napajanje s padavinami in na mešanje podzemnih vod (primera sinklinale Naal-e-Asbi in antiklinale Šaviš-Tanoš). Najvišja vrednost v tretji skupini (vzorci antiklina- le Kamarderaz) je posledica delno izhlapevanja in daljše razdalje med mestoma napajanja in iztekanja ter delno difuzijskega siste- ma. Trend padanja Sr2+ in naraščanja Ba2+ v vzorcih v formacijah dolomitnih apnencev (antiklinali Šaviš-Tanoš in Mongašt) v pri- merjavi z vzorci vode antiklinale Kamarderaz in sinklinale Naal- -e-Asbi kaže na možnost, da se kraški vodonosniki napajajo iz območja antiklinale Mongašt, in na hidravlični odnos med temi strukturami. Devterijev presežek in δ18O kažeta linearni trend, ki ponazarja učinek višinske razlike na vsebnost izotopov in vire napajanja. Večje in manjše spremembe v koncentraciji ionov, vsebnosti izotopov v podzemni vodi in razmerju med TDS in δ18O ter devterijevim presežkom in δ18O kažejo na mešanje in napajanje kraških vodonosnikov (vodonosniki Šaviš-Tanoš, Ka- marderaz in Naal-e-Asbi) s kraškega vodonosnika Mongašt in na njihovo hidravlično povezanost. Ključne besede: Izeh, kemijski, izotopi, kras, hidravlična po- vezava. samples of springs and wells in the region shows three groups of water sources. The first group, related to the Mongasht anticline springs, has lower isotopic values, indicating that it is recharged by rainfall at high altitudes and snow melting. The isotopic value of the second group is richer than that of the first group, indicating rainfall recharge as well as groundwater mixing (ex- amples of Naal-e-Asbi syncline and Shavish-Tanosh anticline). The highest value in the third group (samples of Kamarderaz anticline) is attributed to evaporation and longer distance from the recharge site to the discharge point, as well as to the diffu- sion system. The trend of decrease in Sr+2 and increase in Ba+2 in the samples of dolomitic limestone formations (Shavish Ta- nosh and Mongasht anticlines) compared to the water samples of Kamarderaz anticline and Naal-e-Asbi syncline indicates the possibility that karst aquifers of the region are recharged from the Mongasht anticline and that there is a hydraulic relation- ship between these structures. D-excess and δ18O show a linear trend, illustrating the effect of altitude difference on isotopic content and recharge sources. The major and minor changes in the concentration of ions, the isotopic content of groundwa- ter and the relationship between TDS and δ18O and d-excess and δ18O indicate the mixing and recharging of karst aquifers (Shavish-Tanosh, Kamarderaz and Naal-e-Asbi aquifers) from the Mongasht karst aquifer and their hydraulic connection. Keywords: Izeh, chemical, isotopes, karst, hydraulic connec- tion. ACTA CARSOLOGICA 52/1 – 202368 al., 2014; Murillo et al., 2015; Sun et al., 2016; Heydarizad et al., 2021; Mokadem et al., 2021; Tian et al., 2021; Vreca & Kern, 2021) that is, not seriously affected by water–rock interaction processes at low temperatures (Marfia et al., 2004). These isotopes have been used in studies of ground- water recharge and flow direction (Marfia et al., 2004; Rodgers et al., 2005; Blasch & Bryson, 2007; Ryu et al., 2007; Singh et al., 2013(, the heterogeneity of aquifer hy- draulic properties (Marfia et al., 2004; Doveri et al., 2013), residence time of groundwater (Rademacher et al., 2003; Mahlknecht et al., 2006), and also the mixing of ground- water from different sources (Coplen, 1993). Several stud- ies have suggested the application of hydrochemical and isotopic tracers to elucidate sources of dissolved ions and hydrogeochemical processes that controls the chemical variability in the multilayered aquifer system (Wang et al., 2018; Liu et al., 2019). Hydrochemistry and stable iso- topes are employed for spring discharge studies (Doctor et al., 2006; Hatipoglu-Bagci & Sazan, 2014). Likewise, de- lineation of the recharge area and distinguishing sources of recharge to the karstic springs have been accomplished by applying hydrochemistry and stable isotopes (Blasch & Bryson, 2007; Bhat & Jeelani, 2015 ). The Izeh plain contains over 60 deep and semi- deep alluvial wells which are utilized for irrigation, but the yield and quality of groundwater are poor due to fine grain sediments. In the karstic terrain of the Izeh area, 21 deep karstic wells are merely exploited for drinking purpose and on average the annual withdrawal is about 20 Mm3. It is to be noted that groundwater extraction from these karstic aquifers is very important and cru- cial in terms of drinking water supply for Izeh City and surrounding villages. Though, a large number of small karstic springs with low discharge (between 1 to 5 l/s) are distributed in different parts of the area, but the out- standing spring is emerging from the western limb of the Monghasht anticline is known as Mal -Agha. On average the annual spring discharge is 1.5 m3 /s which is a signifi- cant water supply for another sub-catchment relatively away from the Izeh area. The geological formations of the Izeh complex karstic terrain are mainly calcareous, but with respect to lithology, morphology and structure are more or less dif- ferent (existence of anticlines and synclines with differ- ent lithology). Integration of the abundant information gathered from different sources is crucial for developing knowledge about the karstic aquifers and their intercon- nection. As hydrochemistry and stable isotopes provide key information to characterize hydraulic connectivity so, in this work, hydrochemistry including major and minor ions and stable isotopes (δ18O and δ2H) of the main karst springs and exploitation wells in the Izeh area were taken into account- to designate the hydrochemical and isotopic behavior of the Izeh karstic terrain and to determine hydraulic interconnection among the karstic aquifers. 1.1. STUDY AREA The study area (Figure 1) occupies 910 km2 and is located between longitude 49° 56´ 30" to 50° 26´ 33" east and lati- tude 31° 26´ 03" to 31° 53´ 00" north at a distance of al- most 183 km in the north east of the Ahvaz City (capital of Khuzestan province). The area experiences a semi-arid climatic condition and, based on 30 years data (1990- 2020), the mean annual temperature is 20.7 °C, and the lowest (5.9 °C) and the highest temperatures (33 °C) were recorded in the February and July respectively. The aver- age annual real evapotranspiration from the free surface of water is 1,632 mm. The average annual rainfall of the area is 760 mm and commonly occurs as thunderstorms in the late autumn to early spring. In spite of relatively high rainfall, the Izeh area suffers from shortage of wa- ter resources and relies on only groundwater for differ- ent consumptions. The great Karun River with 200 m3/s average annual discharge flows in the northern part of the study area, but water supply from the river in the study area is crucial due to the mountainous nature of the command area. On the other hand, the Izeh alluvial plain is mainly composed of the fine clay-silty sediments and essentially poor for water infiltration, percolation and accumulation forming a promising aquifer. 1.2. GEOLOGICAL SETTING From the geological point of view, the study area is situat- ed on the southern flank of the folded Zagros domain in the Zagros Mountain Range (Stocklin, 1974; Alavi, 1996) that evolved by different orogeny during the Cimmerian and Alpine orogeny (Alavi, 1996; Zanchi et al., 2009). Such geological events resulted in an extremely complex geology and asymmetric structures (Stocklin, 1974); however, the Cenozoic compressional events masked al- most all of the earlier structural events data. The main exposed geological formations in the area with respect to age include Daryan-Fahlian limestone (Lower Cretaceous), Ilam-Sarvak limestone-dolomite (Upper Cretaceous), Asmari limestone (Oligocene to Miocene) and the Shaly-Marly Pabdeh-Gorpi formation (Upper Cretaceous to Eocene). The majority of the geo- logical structure (folds and fault), including Mongasht, Shavish-Tanosh, Kamarderaz anticlines, and the Naal-e- Asbi are trending NW–SE. The asymmetrical single limb Kamarderaz anti- cline trending NW-SE, extending parallel to the Shavish- Tanosh anticline are composed of the Asmari limestone. The permeable limbs are mostly surrounded by the Pab- deh-Gorpi impermeable formation. In the western limb SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN ACTA CARSOLOGICA 52/1 – 2023 69 of the monocline a thrust fault with about 10 km lengths, sloping gently in NW-SE direction, while the majority of the medium size faults trending NE-SW is stretched between the Kamarderaz and the Mongasht anticlines (Figure 1). 1.2.1. MONGASHT The asymmetric fan fold Mongasht anticline trending NE-SW is the largest structure in the area and the Izeh basement fault which caused a change in its trend also resulted in to bend the mid axis. At limbs and hinge line the consolidated carbonate rock is thick and uniform whereas marl and shaly layer thickness are variable and acting as slippery zones. Geometrically, the Mongasht anticline is cylindrical in form and plunging down be- neath the younger sediments on both ends. The slope in the eastern part of the anticline is relatively gentle and characterized by NE-SW directing fault lines that overturned the limestone layers resulting to merge the Mongasht and Shavish-Tanosh anticlines. Apart to this fault line, the deep fault systems occurrence in different directions is frequent in many parts of the Mongasht an- ticline (Figure 1). Remarkable faults (more than 10 km) including the Sepran and the Mongasht thrust are lo- cated in the southwestern part of the Mongasht anticline and playing a significant role in groundwater movement and hydraulic connection between the water-bearing ho- rizons like Shavish-Tanosh and Kamarderaz anticlines, and the Naal-e-Asbi. The geological fractures at every scale occurred along with faults and these discontinuities provide the necessary permeability for migration and ac- cumulation of groundwater. KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Figure 1: Geological map of the study area and locations of the meteoric water, springs and wells sampling in the Izeh karst catchment. ACTA CARSOLOGICA 52/1 – 202370 1.2.2. SHAVISH -TANOSH The coupled (conjugated) Shavish-Tanosh anticlines di- recting NW-SE, composed of the Ilam-Sarvak limestone, and the fracture density is moderately more in the east- ern limb with respect to the western one. 1.2.3. KAMARDERAZ ANTICLINE This eroded single-sided anticline with the general trend of northwest-southeast stretches parallel to the Shavish- Tanosh anticline and is composed of the Asmari lime- stone. The western and eastern sides of the Asmari for- mation are partly occupied by the impermeable Pabdeh formation. In the southern parts of the anticline, the forces of the tectonic activity have caused the layers to turn. The dominant faults trend is northeast-southwest and there is a thrust fault approximately 10 km long with a slope to the southwest at the northeastern edge of the anticline. 1.2.4. NAAL-E-ASBI SYNCLINORIUM The Naal-e-Asbi symmetrically folded synclinorium ex- tending 12 km with a width of 2 km in the NW-SE direc- tion and can be divided into north and south sections (Figure 1). This synclinorium is located between the Pion anticline in the north and the Shavish-Tanosh anticline in the south and this is the main and accessible place for groundwater extraction in the Izeh area. Based on Figure 2, it can be stated that the infiltra- tion of water in the limestone formations of Ilam-Sarvak and Fahlian-Darian in the Mongasht anticline has cre- ated a large karst aquifer. The groundwater of the Mon- gasht karst aquifer flows deep and move through large faults from the Mongasht anticline to the Kamarderaz, Shavish-Tanosh and Chalkhoshk anticlines in the south- ern parts of the region. Also, the existence of faults and fractures between the Mongasht anticline and the Naal- e-Asbi syncline has caused water to penetrate in to the Naal-e-Asbi syncline. 1.2.5. HYDROGEOLOGY OF IZEH AREA Morphologically the Izeh plain is an open polje with gentle slopes forming a large lake called as Miangran. The geological formation of the plain which ranges from Upper Cretaceous to the current age consists of heteroge- neous alluvial deposits overlying consolidated sedimen- tary rocks. The Izeh plain has an unconfined ground- water system in unconsolidated sediments while the karstic aquifers occupying the surrounding of the plain composed of massive and highly fractured limestone and dolomite-limestone in a tectonically complex zone. The thickness of the Izeh alluvial sediments ranges from 60 m in the southeast to over 150 m in the northwest. Fine sediments such as silt, clay, and fine sand are de- posited underneath the lake at approximately 70 m depth (Alijani, 2003). Most of the Izeh alluvial plain recharge is related to precipitation and the water table depth ranges from 1.5 m to more than 50 m. The annual discharge of the Izeh alluvial plain unconfined aquifer through exploi- tation wells is about 8.65 Mm3. Using the absolute water level of the piezometers, water table map of the Izeh plain aquifer for October 2021 was prepared indicating flow direction (Figure 3). In general, four unconfined karst aquifers are recog- nized (Figure 2) and playing a significant role concern- ing drinking water supply of the area. The depth of Izeh area karstic wells varies from 130 to 290 meters and their discharge ranges from 15 to 65 liters per second and the annual discharge is about 19 Mm3. The Asmari limestone karstic aquifer contains high storage capacity as well as a dominated base flow and the dolomite Ilam-Sarvak karst in the Shavish-Tanosh anti- cline is an intermediate aquifer with quick-flow and low storage capacity (Nassery et al., 2013). The characteristics of the dolomite Ilam-Sarvak karst in the Mongasht anti- cline are similar to the Asmari limestone formation. The karstification of the Asmari formation and the dolomite Ilam-Sarvak karst in the Mongasht resulted in coexist- ing fracture and conduit flow and unlike the Ilam-Sarvak karst aquifers in the Shavish-Tanosh anticline, the ma- trix could also easily transmit horizontal flow. The Ilam- Sarvak karst aquifers in the Shavish-Tanosh anticlines lie between two extremes, of low and high karstification and SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN Figure 2: Geological section in the path A-B (Figure 1). ACTA CARSOLOGICA 52/1 – 2023 71 thus, the groundwater system is experiencing quick and low base flow. The limestone complex and the dolomite Ilam-Sar- vak karst in the Mongasht anticline exhibits brittle be- havior under tectonic stresses, favoring propagation and development of wide fracture networks that are exten- sively karstified. In the Mongasht complex, groundwater flow is concentrated towards the lower reaches karstic aquifers including; the Shavish-Tanosh and Kamarderaz anticlines, and the Naal-e-Asbi syncline. In the Izeh area, many low discharge springs (1– 5 L/s) are observed, but from the western limb of the Mon- gasht anticline a considerable spring (Mal-Agha) emerg- ing out with an annual average discharge of 1.5 m3 L/s at an elevation of about 2000 m a.s.l (Table 1; Figure 2) The spring is fed by the highly fractured and karstified dolo- mite rock, which is surrounded by thick sequences of less permeable deposits. 2. MATERIALS AND METHODS A total 25 groundwater (8 springs and 17 wells) the same locations were sampled twice in January 2020 (wet sea- son) and May 2021(dry season) and 6 rain water samples from selected locations. For evaluation of the stable iso- tope content of rain water (rainwater samples were sam- pled from higher altitude feeding areas and lower altitude discharge areas), the main karst springs and wells in the karstic aquifer system, samples were analyzed. The sam- ples were taken from pumping wells and springs across the study area (Figure 1) Water from wells in the area is KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Figure 3: Map of groundwater flow directions of Izeh plain. ACTA CARSOLOGICA 52/1 – 202372 SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN Table 1a: Physico-chemical characteristics of the karst springs and wells in the Izeh area (mg/L). January, 2020. Name Location ID pH EC μS/cm T C° TDS Na + K+ Ca+2 Mg+2 HCO3 - SO4 -2 Cl- Percentage of analysis errors Abgol (S) Mongasht SM1 8.2 320 12.8 247.2 1.1 0.4 44.1 9.7 183.1 1.9 7.1 1.44 Malagha1(S) SM2 8.2 429 12 312.4 1.8 0.4 64.1 10.3 198.3 28.8 8.9 0.01 Malagha2(S) SM3 8.1 330 11 242.9 1.4 0.4 40.1 12.2 173.9 2.9 12.4 2.87 Takab(S) Naal-e-Asbi SN1 8.2 278 18 209 3.2 0.4 48.1 1.2 140.3 5.3 10.6 0.49 Kaldozakh WN1 7.3 707 23 532.7 20.2 1.2 72.1 32.8 366.1 7.2 33.7 3.00 Jamoshi WN2 7.4 674 22 466.9 19.8 1.2 70.1 29.2 308.1 7.2 31.9 1.08 Lavaii 1 WN3 7.9 377 21 288.2 13.1 0.4 48.1 12.2 195.3 5.3 14.2 0.76 Lavaii 2 WN4 7.5 744 22 521 27.8 1.2 66.1 32.8 335.6 12 46.1 4.64 Bardboran 1 WN5 7.6 471 23 322.7 13.6 0.4 56.1 10.9 216.6 7.7 17.7 3.49 Bardboran 2 WN6 7.5 498 22 373.3 14.7 0.8 63.1 13.9 250.2 4.3 26.6 1.33 Porarshad WN7 7.6 551 21.5 394.9 16.6 0.8 68.1 16.4 259.3 5.8 28.4 1.07 Abrak WN8 7.8 469 22.9 314.5 12.2 0.4 52.1 15.8 204.4 8.7 21.3 0.20 Kohbad 1 WN9 7.7 593 23.7 396.1 25.3 1.2 60.1 22.5 195.3 10.6 81.5 3.00 Kobad 2 WN10 7.6 582 21.8 382.3 33.3 0.8 58.1 19.4 186.1 19.2 65.6 3.62 Chega WN11 7.4 584 20.5 431.8 11.04 0.8 66.1 25.5 308.1 4.8 15.9 2.21 Tekyeh 1 Kamarderaz SK1 7.2 716 24 548.5 19.1 1.2 86.2 27.9 381.4 19.2 14.2 4.30 Tekyeh 2 SK2 7.8 626 18 478.7 17.7 1.2 64.1 30.4 329.5 24.02 12.4 2.62 Abgorazi SK3 7.9 782 20.9 554.5 14.7 1.2 109.2 19.4 381.4 9.6 19.5 2.82 Monareh SK4 8.1 455 22.9 348.3 7.1 0.8 64.1 15.8 238 8.7 14.2 1.96 Number 1 rostaii WK1 7.7 721 24.6 519.8 55.4 1.6 70.1 18.2 231.9 72.1 70.9 3.29 Number 2 Halayegan WK2 7.8 542 22.7 387.6 19.1 1.2 50.1 20.7 238 36 23.04 3.75 Number 3 Halayegan WK3 7.8 451 24.7 353.8 14.7 0.8 52.1 17 231.9 28.8 8.9 1.01 Number 4 Halayegan WK4 7.8 528 23.2 388.3 26.2 1.2 60.1 13.4 222.7 38.4 26.6 2.33 Number 5 Tangsofla Shavish- Tanosh WT1 7.6 500 23.7 398.4 11.9 1.2 70.1 18.2 280.7 9.6 7.09 0.09 Number 6 Tangoliya WT2 7.6 500 23.7 404.4 12.6 1.2 88.2 7.3 274.6 12 8.9 0.67 AVR 7.73 537.12 20.70 392.73 16.55 0.90 63.63 18.12 253.23 15.60 25.11 2.08 MAX 8.20 782.00 24.70 554.50 55.40 1.60 109.2 32.8 381.40 72.1 81.5 4.64 MIN 7.2 278.0 11 209.0 1.1 0.4 40.1 1.2 140.3 1.9 7.09 0.01 extracted using pumps. Physical parameters such as pH, temperature, electrical conductivity, total dissolved sol- ids were measured in situ using standard field equipment such as Mercury in glass thermometer, digital mvRedox pH meter, conductivity meter, WA 3000, and spectro- photometer respectively. Major anions and cations were analyzed using titration, chromatography and flame test in the Zagros Abshenas Laboratory respectively. The trace elements were measured using inductively coupled plas- ma-mass spectrometry (ICP-OES), using acid digestion method with hydrofluoric acids, sulfuric acid, nitric acid and Perchloric acid in the Zarazma Laboratory. The isoto- ACTA CARSOLOGICA 52/1 – 2023 73 Table 1b: Physico-chemical characteristics of the karst springs and wells in the Izeh area (mg/L). May 2021. Name Location ID pH EC μS/cm T C° TDS Na + K+ Ca+2 Mg+2 HCO3 - SO4 -2 Cl- Percentage of analysis errors Abgol Mongasht SM1 8.3 320 13.3 234.3 0.91 0.39 50.1 7.9 140.3 21. 3 1.8 2.8 Malagha1 SM2 8.3 343 15 242.8 0.91 0.4 44 14.5 140.3 23.1 1.8 2.8 Malagha2 SM3 8.2 408 12 298.5 1.1 0.8 53.1 16.4 195.3 14.9 5.3 3.01 Takab Naal-e-Asbi SN1 8.1 287 20 455 3.8 1.6 64.1 39.5 292.9 42.3 63.8 3.1 Kaldozakh WN1 7.4 781 25 527.1 23.6 1.5 60.1 34.6 299 52.8 30.1 3.2 Jamoshi WN2 7.5 675 24 498.3 20.7 1.6 80.1 28.5 305.1 40.8 42.5 2.8 Lavaii 1 WN3 7.8 713 23 526.4 28.3 1.2 68.1 19.4 268.5 40.8 15.9 3.1 Lavaii 2 WN4 7.6 584 25 430.8 17.2 1.5 60.1 32.2 305.1 48.03 30.1 3.1 Bardboran 1 WN5 7.7 689 25 503.9 27.4 0.7 60.1 15.8 247.1 9.6 8.8 3.2 Bardboran 2 WN6 7.7 452 26 346.7 4.8 1.1 56.1 29.2 292.9 32.2 14.2 3.3 Porarshad WN7 7.5 580 27 440.7 15.6 1.6 76.1 32.8 274.6 31.2 99.3 2.7 Abrak WN8 7.5 785 25.9 550.4 35.4 1.5 90.1 18.2 244.1 38.4 106.4 2.3 Kohbad 1 WN9 7.6 785 26.5 552.9 54.4 1.9 80.1 45.5 213.6 156.1 124.1 2.3 Kobad 2 WN10 7.7 1021 24.5 703.7 82.9 1.9 90.1 42.5 210.5 180.1 120.5 2.2 Chega WN11 7.5 1121 23.5 733.8 88.7 1.5 40.0 63.1 305.1 88.9 88.6 3.5 Tekyeh 1 Kamarderaz SK1 7.5 741 25 514.9 8.27 4.3 80.2 26.7 198.3 24.02 28.4 1.9 Tekyeh 2 SK2 7.7 759 19 1376. 16.09 1.17 60.1 21.3 274.6 12.01 5.3 3.4 Abgorazi SK3 7.6 496 22.9 377.2 3.219 2.7 80.1 42.5 180 216.1 184.4 2.2 Monareh SK4 7.6 476 23.9 387.6 8.1 1.9 70.1 36.4 201.4 170.5 54.9 2.4 Number 1 rostaii WK1 7.5 1264 26.6 839.1 23.8 1.2 60.1 21.9 161.7 88.9 26.6 2.5 Number 2 Halayegan WK2 7.4 864 27.7 614.3 37.5 1.3 52.1 24.3 195.3 92.7 19.5 2.9 Number 3 Halayegan WK3 7.7 561 28.8 385.6 25.7 1.4 60.1 13.4 222.7 38.4 26.6 2.8 Number 4 Halayegan WK4 7.6 565 26.3 411.2 26.6 1.1 65.1 28.5 265.4 24.9 8.8 3.4 Number 5 Tangsofla Shavish- Tanosh WT1 7.5 520 26.4 384.5 5.9 1.27 50.1 30.4 259.3 36.5 8.8 3.4 Number 6 Tangoliya WT2 7.4 527 25.8 391.5 5.7 1.3 50.1 31.9 140.3 21.1 1.7 2.7 AVR 7.7 652.6 23.5 509.2 23.4 1.5 64.1 28.7 233.3 61.8 41.5 2.8 MAX 8.3 1264 28.8 1376.9 88.7 4.3 90.1 63.1 305.1 216.1 184.4 3.5 MIN 7.4 287 12 234.3 0.9 0.3 40 7.9 140.3 9.6 1.8 1.9 KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN pic samples (30 samples in two seasons (6 rainwater sam- ples in January 2020, 7 spring samples and 17 well samples in two seasons, table 4) were analyzed for δ2H and δ18O values with precision ±0.1‰ for δ18O and ±1‰ for δ2H in the Mesbah Energy Laboratory of Arak with the use of Off- Axis-integrated- Cavity- Output- Spectroscopy (OA- ICOS). Stable isotope ratios are reported in parts per mille (‰) using the conventional delta notation. For hydro- chemical interpretation and to get knowledge about the hydraulic connection between karstified and water bear- ing structures various graphs, including, Gibbs (1970) and Langelier and Ludwig (1942) were taken into account. ACTA CARSOLOGICA 52/1 – 202374 SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN 3. RESULTS AND DISCUSSION 3.1. HYDROCHEMICAL CHARACTERISTICS The hydrochemical properties of groundwater samples for two seasons (wet and dry) are shown in Tables 1a and 1b, and the chemical ionic balance is also presented. The pH of groundwater samples is slightly alkaline and varies from 7.18 to 8.22. The temperature varies from 12.8 °C to 24.8 °C with a mean value of 19 °C. The EC and TDS of the groundwater samples varying from 278 to 1325 μS/ cm and 209 to 944 mg/L respectively. The rise of EC in wells WN1, WN2 and WN4 located in the Naal-e-Asbi can be considered as a result of reversing groundwater flow direction from the alluvial aquifer into the Naal-e- Asbi karstic aquifer. Reversing the flow direction is due to recent droughts and excessive water abstraction from the calcareous aquifer, which caused the karstic aquifer water level to recede with respect to the alluvial aquifer (Kalantari et al., 2009). There are low differences in water temperatures and Table 2: Information’s about groundwater sources, containing wells and springs. Name Location ID Altitude Well depth Discharge m m L/s Abgol (Spring) Mongasht SM1 1041 - 6 Malagha1 (Spring) SM2 2238 - 2/4 Malagha2 (Spring) SM3 2218 - 2/2 Takab (Spring) Naal-e-Asbi SN1 989 - 1 Kaldozakh WN1 841 180 30 Jamoshi WN2 861 240 35 Lavaii 1 WN3 838 260 37 Lavaii 2 WN4 838 230 30 Bardboran 1 WN5 942 180 9.8 Bardboran 2 WN6 857 200 32 Porarshad WN7 841 150 12 Abrak WN8 883 150 50 Kohbad 1 WN9 838 130 62 Kobad 2 WN10 840 220 50 Chega WN11 900 150 30 Tekyeh 1 (Spring) Kamarderaz SK1 1041 - 0/5 Tekyeh 2 (Spring) SK2 1038 - 0/1 Abgorazi (Spring) SK3 1143 - 0/2 Monareh (Spring) SK4 916 - 0/8 Number 1 rostaii WK1 858 90 40 Number 2 Halayegan WK2 861 110 15 Number 3 Halayegan WK3 856 120 46 Number 4 Halayegan WK4 855 120 30 Number 5 Tangsofla Shavish-Tanosh WT1 855 150 65 Number 6 Tangoliya WT2 850 220 15 ACTA CARSOLOGICA 52/1 – 2023 75 EC change in the wet and dry seasons. The concentra- tion of SO4 −2 ion placed between 1.9 mg/L to 72.1 mg/L with an average of 15.6 mg/L, and the highest and low- est sulfate concentration was observed in the well sample (WK1) and SM1 and SM2 springs respectively. The data concerning the karstic wells depth, altitude and discharge rate and the springs discharge and altitude is given in Table 2. The wells depth varies from 90 to 260 meters and their discharge rate ranges from 15 to 65 L/s. The annual abstraction from the Izeh karst aquifers for drinking is 18.65 Mm3. Of course there is a difference in water usage in the wet (5,927 Mm3) and dry (12,723, Mm3) seasons. The location of the samples in the Durov diagram (Figures 4a-b) indicates that wells and springs are domi- nantly from similar geological units comprising of the Asmari limestone (Oligocene to Miocene) and the Ilam- Sarvak limestone-dolomite (Upper Cretaceous). The Du- rov plot for groundwater samples indicates that most of the samples are in the phase of mixing dissolution. Increasing Cl- can be attributed to the dissolution of halite in alluvium and the reversal of the flow from the Izeh aquifer to the kartic aquifer (Srivastava & Ramana- than, 2008). 3.1.1. HYDROCHEMICAL PROCESSES The binary diagrams of the major elements (Figure 5) confirm that dissolution and water-rock interactions are the dominant factors to control groundwater chemistry. Based on the comparison between Ca+2 vs. HCO3 -, Mg+2 vs. HCO3 - and Ca+2 vs. Mg+2 (Figures 5a-c), it seems that there is a notable difference in the kinetic of calcite and dolomite dissolution. Two different processes occur suc- cessively; first, a congruent dissolution of calcite with marginal contribution of dolomite until saturation with respect to calcite and its subsequent precipitation and KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Figure 4: Durov plot of chemical analysis of the groundwater samples, wet season (a) and dry season (b). ACTA CARSOLOGICA 52/1 – 202376 SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN Figure 5: Plot of Ca+2 vs. HCO3 - (a), Mg+2 vs. HCO3 - (b), Ca2+ vs. Mg2+ (c), Ca2+/Mg2+ vs. Mg (d), Ca2+/Ca2+ + Mg2+ vs. SO4 2−/SO4 2−+ HCO3 − (e), Ca2+ + Mg2+ vs. HCO3 −(f), Ca2+ + Mg2+ vs. SO4 2− + HCO3 − (g) and Na+ vs. SO4 2− for the groundwater samples (h). ACTA CARSOLOGICA 52/1 – 2023 77 second, an incongruent dissolution of dolomite (Celle- Jeanton et al., 2001; Emblanch, 2003). The dedolomiti- zation induces a gradual enrichment in magnesium and gradual depletion of calcium (Figure 5c) related to affect of rocks porosity and density (Nader et al., 2003; Ren & Jones, 2017; Makhloufi et al., 2018). The composition of the karstic water systems is due to dissolution of variable quantities of calcite and dolo- mite. The proportion of calcite and dolomite in an aquifer is, together with the transit time, one of the basic factors influencing the chemical composition of karstic waters. Hence, the Mg+2/Ca+2 ratios are often used as a good in- dicator of residence time. Calcite dissolves more quickly than dolomite and shows a rapid equilibrium with the hosted rock while Mg+2 concentrations reveal a progres- sive increase with flow paths and residency (Figure 5d). More evolved water in the Kamarderaz anticline and the Naal-e-Asbi has higher temperature, magnesium con- tent and Mg2+/Ca2+ ratio; therefore, these parameters can be utilized as indicators of the degree of hydrochemical evolution. In addition, a good correlation between wa- ter temperature and magnesium concentration or Mg+2/ Ca+2 ratios indicates that an increase in temperature ac- celerates the kinetics of the dissolution of dolomite. The higher temperatures tend to accelerate the kinetics of the dolomite dissolution reaction (Moral et al., 2008). Also in the Ca2+/Ca2++Mg2+ vs. SO4 2-/SO4 2-+HCO3 - in Figure 5e, high values of Ca2+/Ca2++Mg2+ indicate the predominant reaction of water with calcite. However, if the water reacts with dolomite, samples position should be in the middle areas of the Figure 5e. The plot of Mg2+/Ca2+ vs. HCO3, (Figure 5f) used to determine the possible sources of Ca2+ and Mg2+ ions in groundwater. It is evident from the Ca2++Mg2+ vs. HCO3 - , that most of the samples fall between the line 0.2 and 1. The Mg2+/Ca2+ molar ratios of the groundwater samples were in the range 0.04 to 0.8 (average: 0.48). As shown in Figure 5f, the Ca2+ concentration in groundwater is mainly controlled by dissolution of calcite and dolomite. This plot reflecting extra sources of HCO3 - ion in the Naal-e-Asbi and Kamarderaz samples, indicating that the calcium carbonate weathering (Asmari formation) it has not sufficient HCO3 - to explain the concentrations. The additional amounts of HCO3 must be supplied from the upper reaches Ilam-Sarvak limestone-dolomite for- mation. Binary plot of Ca2++Mg2+ vs. SO4 −2 + HCO3 − (Fig- ure 5g) in study area shows that most of the samples fall around the 1:1 line which indicates that dissolution of calcite, dolomite and gypsum are the dominant reactions in the system (Zaidi et al., 2015). Extra amounts of Ca2+ + Mg2+ over SO4 2− +HCO3 − indicate the ion exchange pro- cess, while excess amounts of SO4 2− +HCO3 − over Ca2+ +Mg2+ show occurrence of reverse ion exchange (Houn- slow, 1995; Zaidi et al., 2015; Badaruddin et al., 2017; Alfarrah & Walraevens, 2018). As shown in Figure 5g, all of the samples spread on the 1:1 line of (Ca2++Mg2+) and (HCO3 −+SO4 2−), depicting the crucial role of the carbonate dissolution. The sample numbers WN2, WN9, and WN10 show deviation from this line indicating the presence of reverse ion exchange (Rajmohan & Elango, 2004). An excess of Ca2++Mg2+ over SO4 2−+HCO3 − may be due to exchange of sodium in water with calcium and magnesium. Increased sodium is due to the reversal of flow direction from the surrounding alluvial aquifers and mixing phenomena. Enrichment of Na+, Mg2+ and SO4 2−, water samples with linear correlation of the SO4 2− and Na+ (Figure 5h) indicates weathering and dissolution of Mg2+ bearing minerals (Zhou et al., 2016), which could be related to the higher altitude of the Ilam-Sarvak formation with re- spect to the carbonate formations in the catchment areas of the springs and wells. Thus, the main geochemical processes in the Izeh karstic aquifers are dissolution of CO2 and calcite, in- congruent dissolution of dolomite, dedolomitization, precipitation of calcite and magnesium enrichment in groundwater. 3.2. HYDRAULIC CONNECTION ASSESSMENT USING MAJOR AND TRACE ELEMENTS Figure 6 shows the general direction of karst flow in the area. Thus, according to the topography of the area, the height decreases from the Mongasht anticline to other structures. Existence of Izeh and Thrust Mongasht foun- dations, as well as faults and longitudinal and transverse fractures in these structures cause hydraulic connection between these structures. Major and minor elements have been extensively used to ascertain geochemical processes and water re- source deterioration, and it is also a tool to determine interconnection between different water bodies (Zhang et al., 2020; Ciner et al., 2021; Jiang et al., 2021; Lewinska- Preis et al., 2021; Pratama et al., 2021; Tang et al., 2021). In the present study, to support the major ions evi- dences, the trace elements have been also considered to trace groundwater flow between karstic aquifers in the area. In order to recognize the minor elements, samples were analyzed for Al+3, As+3, Ba+2, Cr+2, Li+2, Mo+2, S+4, Si+2, Sr+2 and Zn+2. Generally, the trace element concentra- tions in karst water are low and are not always detectable. The measured values of the minor elements in the karstic aquifers show in Table 3: The ionic values of groundwater samples suggested that the chemical evolution of groundwater was main- ly related to the geogenic process and recharge water. KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN ACTA CARSOLOGICA 52/1 – 202378 Therefore, in accordance with correlation matrix, major ions ratios and the relationship of major ions and some heavy metals such as Li+2, Sr+2, Ba+2, Zn+2, Cr+2, Mo+2, Si+2 were used to designate common origin of water, hydrau- lic interrelationship and groundwater exchange between the karstic aquifers in the command area. Heavy metals that play a key role in determining the origin of calcite water and are present in the region. The Pearson correlation matrix (Table 4) was used to assess the relationships between the hydrochemical parameters and to disclose recharge sources of different elements. When the correlation coefficient (r) is greater than 0.7, parameters are viewed to be firmly correlated, while if the r value is between 0.5 and 0.7, it depicts a moderate to noteworthy level of correlation (Rudy et al., 2020). The negative correlation of EC with pH implies their inverse relationship in dissolution processes, and demonstrating enhancing decomposition of soluble materials with decreasing pH and acidity. Negative pH correlation with other ions is attributed to the high cor- rosion of the acidic environment relative to the soil and host rock, which increases the concentration of ions fur- ther (Helena et al., 2000). P-Value "probability with meaning" or Sig helps us to decide whether or not to reject the null hypothesis without referring to tables of statistical distributions. Ac- cording to the Sig values in Table 4, it can be said that there is the highest probability of correlation between the elements Ca+2, Mg+2, HCO3 - and Sr+2. There is a high relationship between EC and Ca+2 (0.81), Mg+2 (0.67), and HCO3 - (0.88), indicating cal- cite and dolomite origin of aquifers. The strong positive correlation between the sodium and chloride can be at- tributed to the dissolution of halite in the alluvium and the reversal of the flow from the alluvial aquifers to the karstic aquifer in the region (Srivastava & Ramanathan, 2008). Based on Figure 7, there is a linear trend between the ratios of Ca+2/Zn+2 and Mg+2/Zn+2, which indicates the common origin of these ions (calcareous forma- tions), and interrelationship of the samples. In karstic areas, dissolution of carbonate rocks leads to the entry of Ca+2, Mg+2 and Sr+2 in groundwater. The increasing trend of Sr+2 ion in the samples close to the calcite formations (Naal-e-Asbi and Kamarderaz) in comparison to concentration of Sr+2 in dolomite forma- tions (Mongasht and Shavish-Tanosh anticlines), reveals the probable groundwater flow from the Mongasht an- ticline to the Shavish-Tanosh, Kamarderaz anticlines and Naal-e-Asbi, and the hydraulic relationship between these structures. Recharge from Shavish-Tanosh dolo- mitic formation has caused the amount of Sr+2 in samples WN5, WN6, WN7 to be less than the calcareous forma- tions samples (Figure 8a). SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN Figure 6: A cross-section of the Mongasht, Shavish-Tanosh, Kamarderaz and Naal-e-Asbi, which shows the merging of these anticlines. Table 3: Descriptive table (min, max, avr) heavy metals of groundwater samples in the study area (N = 25). Elements Al+3 As+3 Ba+2 Cr+2 Li+2 Mo+2 S+4 Si+2 Sr+2 Zn+2 Minimum 11 120 7.8 1200 1.1 0.21 1600 2030 150 1.12 Maximum 180 6500 208 2400 17.8 4.4 61360 9220 4090 293 Avr 20 80 50 500 6 0.1 13100 6200 1600 20 ACTA CARSOLOGICA 52/1 – 2023 79 Also by using the ratios of Ca+2/Sr+2 and Mg+2/Sr+2 the origin of karst waters can be determined (Negrel & Petelet-Giraud, 2005). Figure 8b shows the very close relationship of Ca+2/Sr+2 and Mg+2/Sr+2 ratio in the karst groundwater of the region and the common origin of these elements (r2=0.83). Of course samples originat- ing from the calcareous formations (Asmari) have lower Mg+2/Sr+2 ratios than the samples from the dolomitic- calcareous formations (Ilam-Sarvak). The significant linear positive correlation between Sr2+/Ca+2 and Sr2+/HCO3 - indicates dissolution of calcium bearing minerals producing Sr2+in the karstic aquifers KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Table 4: Correlation matrix of the trace elements in groundwater samples. EC pH Ba+2 Cr+2 Li+2 Mo+2 Si+2 Sr+2 Zn+2 Ca+2 Mg+2 Na+ K+ HCO3 - SO4 -2 Cl- EC 1 pH 0.7 1 Ba+2 0.74 -0.48 1 Cr+2 0.39 -0.39 0.45 1 Li+2 0.76 -0.8 0.77 0.55 1 Mo+2 0.48 -0.52 0.31 0.22 0.79 1 Si+2 0.72 -0.66 -0.09 -0.33 0.07 0.28 Sr+2 0.31 -0.38 0.64 0.37 0.68 0.47 1 Zn+2 -0.27 0.26 0.25 0.48 0.51 0.43 0.26 1 Ca+2 0.73 -0.45 -0.16 -0.14 -0.28 -0.21 -0.41 -0.34 1 Mg+2 0.81 -0.74 0.74 0.27 0.58 0.42 0.57 -0.03 -0.25 1 Na+ 0.67 -0.51 0.68 0.43 0.81 0.51 0.66 0.46 -0.15 0.35 1 K+ 0.8 -0.59 0.11 0.06 0.3 0.19 0.45 0.33 -0.23 0.24 0.44 1 HCO3 - 0.8 -0.6 0.5 0.08 0.51 0.42 0.64 0.16 -0.23 0.62 0.59 0.71 1 SO4 -2 0.29 -0.04 0.89 0.47 0.87 0.62 0.71 0.24 -0.16 0.79 0.74 0.19 0.62 1 Cl- 0.5 -0.3 -0.14 -0.36 -0.03 0.19 0.07 0.07 -0.19 0.07 0.04 0.69 0.49 -0.07 1 Sig. 0.25 0.54 0.01 0.02 0.16 0.12 0.05 0.47 0 0.47 0.95 0.001 0.03 0.58 0.01 0.01 Figure 7: The covariation of Ca+2 / Zn+2 vs. Mg+2 / Zn+2. ACTA CARSOLOGICA 52/1 – 202380 (Figure 8c). Furthermore, there is a significant positive correlation between Ca2+, Mg2+, HCO3 - and Sr2+ (Figures 8 a-c), which reflects that the changes of Sr2+ as well as Ca2+ and Mg2+ concentrations in groundwater are caused by calcite and calcite- dolomite dissolution in ground- water. These negative and positive correlations between the variables indicate governing factors controlling hy- drochemical process, evolution of groundwater and com- mon origin of ions. Because the dolomite rocks have more magnesium and less barium than the calcite rocks, groundwater from the calcareous formations has relatively low Mg+2 and more Ba+2 than the dolomite rocks (Fairchild et al., 2000). According to the above, the springs and wells dolo- mitic (SM1, SM2, SM3, WT1, WT2) have less ratio Mg +2/ Ba+2 vs Ca+2/Ba+2 (Figure 9a) than samples of calcite (WK, WN). Due to the water flow due to the topography of from the Mongasht anticline to others structure (Naal-e- Asbi, Shavish-Tanosh and Kamarderaz), the water mix- ing of these structures has brought the values of this ratio and linear process (water mixing). Figure 9b show clearly liner trends in the distribu- tion of the samples pertaining to the Mg+2 vs. Ba+2 ratio. The increasing trends of the ion ratios from the Mongasht anticline (SM1, SM2, and SM3) to the Shavish-Tanosh (WT1, WT2), Kamarderaz (WK) and Naal-e-Asbi (WN) structures prove their hydraulic connection. To better understand the relationship between the structures of the region, in this section, the northern and southern limbs of the Naal-e-Asbi syncline are discussed separately. The northern limb of the Naal-e-Asbi naviga- tor is close to the Mongasht anticline and the southern limb of this syncline is close to the Shavish-Tanosh an- ticline. Therefore, it is assumed that the northern limb is by the Mongasht anticline. The southern limb is also af- fected by mixed waters of Shavish-Tanosh and alluvium. In addition to correlation coefficient assessment of the major and trace elements, another approach, includ- ing plot of the major elements (Ca+2, Mg+2 and HCO3 -) with trace elements (Li+2, Cr+2, Mo+2) and trace elements with each other was undertaken. The results indicated that samples of different locations; except the southern nose of the Naal-e-Asbi and one or two from the Ka- marderaz anticline which are partly recharging from the SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN Figure 8: The value of Mg+2/Ca+2 and Sr+2 (a), Ca+2 / Sr+2 vs. Mg+2 /Sr+2 (b), Sr+2/HCO3 - vs. Sr+2/Ca+2 (c) in groundwater structures of the region ACTA CARSOLOGICA 52/1 – 2023 81 KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Figure 9: The covariation of Ba+2/ Mg+2vs Ba+2/Ca+2 (a) and Ba+2 vs. Mg+2 (b) in groundwater of the area. Figure 10: The covariation of Li+2 vs. Mg+2 (a), HCO3 -(b), Cr+2 (c) and Mo+2 (d) in groundwater of the area. nearby alluvial aquifers, depicting close relationship. The interrelationship of the karstic samples (they are related in terms of hydrochemistry and hydraulic connection) is represented as a cluster or nearly trending pattern, realiz- ing the hydraulic connection among the karstic aquifers. As shown in Figure 10, there is also a good association between the Mongasht samples (SM1, SM2, and SM3) and Shavish-Tanosh (WT1, WT2) and the northern part of the Naal-e-Asbi samples (WN). The Southern Naal-e- Asbi and Kamarderaz samples are affected by alluvium recharge water. 3.3. ISOTOPIC CHARACTERISTICS The oxygen (δ18O) and hydrogen (δ2H), d-excess, tem- perature and altitude of the sampling points are given in Table 3. The isotopic composition of precipitation ranged between -4.9 to -1.87‰ and -24.14 to -2.9‰ for δ18O and δ2H respectively. The local meteoric water line ACTA CARSOLOGICA 52/1 – 202382 (LMWL) which is placed above the global meteoric water line (GMWL), has a slope less than the GMWL and the position difference is related to local climatic conditions (Figure 11). Deuterium excess (d-excess) is a second-order stable isotope parameter measured in meteoric water to under- stand both the source of precipitation and the evolution of moisture during transport. The d-excess precipitation is related to the kinetic fractionation processes that occur during evaporation of water, and is mainly affected by the relative humidity (Jouzel et al., 2007; Bershaw, 2018), temperature in the moisture’s source area (Dansgaard et al., 1989; Frohlich & Gibson, 2015), the evaporation con- ditions (Johnsen et al., 1989; Chen et al., 2004; Masson- Delmotte et al., 2005), and the vapor transport processes. The d-excess therefore can offer insights into the climatic processes at the time the precipitation falls (Dansgaard et al., 1989). Therefore, in general the observed change of deuterium excess is dependent upon humidity, tempera- ture, altitude and evaporation. The d-excess higher than 20‰ in precipitation sam- ple results from arid vapor sources. The vapor sources of some precipitation samples (RK2 and RT) are indicating aridity with low humidity. Apart to the low humidity of vapor source the higher d-excess may be due to tempera- ture, altitude difference, evaporation difference and mi- SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN Table 5: Isotopic values (‰), altitude and temperature of the samples. NO Samples Location δ2H (Wet) δ18O(Wet) δ2H (dry) δ18O(dry) d-excess T(°C) Altitude 1 RA Mongasht -9.11 -3.33 - - 17.53 12.9 1153 2 RAB -24.14 -4.85 - - 14.66 12.1 1334 3 RB Shavish-Tanosh -4.32 -1.87 - - 10.64 14.1 681 4 RK1 Kamarderaz -8.68 -3.1 - - 16.12 12.4 889 5 RK2 -2.9 -2.87 - - 20.06 13.4 1003 6 RT Naal-e-Asbi -18.45 -4.9 - - 20.75 9.5 973 7 SN1 Naal-e-Asbi -12.42 -2.44 - - 7.1 18 1027 8 WN1 -15.44 -3.65 -20.14 -5.09 13.76 23 853 9 WN2 -15.54 -3.5 -19.8 -4.96 12.46 23 847 10 WN3 -12.29 -3.75 -20.1 -5.03 17.71 22 861 11 WN4 -14.58 -3.49 -20.77 -5.28 13.34 22 861 12 WN5 -8.57 -3.62 -21.93 -5.23 20.39 21 859 13 WN6 -12.65 -3.93 -21.32 -5.06 18.79 22 862 14 WN7 -14.79 -4.01 -20.66 -4.68 17.29 21.5 839 15 WN8 -15.13 -4.05 -20.74 -4.42 17.27 22.9 861 16 WN9 -15.04 -3.84 -20.15 -4.38 15.68 23.7 853 17 WN10 -14.53 -3.8 -16.48 -3.8 15.87 17.8 845 18 WN11 -14.5 -4.05 -18 -3.65 17.9 16.5 920 19 SM1 Mongasht -23.04 -5.62 -31.26 -6.32 21.92 12.8 1915 20 SM2 -21.47 -5.6 -29.33 -5.88 23.33 18 1218 21 SM3 -27.06 -4.87 -29.47 -5.91 11.9 20 1211 22 WK1 Kamarderaz -16.02 -3.98 -23.62 -4.36 15.82 24.6 815 23 WK2 -19.87 -3.47 -22.22 -3.99 7.89 22.7 819 24 WK3 -19.37 -3.63 -22.94 -4.11 9.67 24.7 847 25 WK4 -17.39 -3.58 -22.87 -4.39 11.25 23.2 810 26 SK1 -22.4 -2.73 -19.79 -3.84 -0.56 24 1037 27 SK2 -21.97 -2.52 - - -1.81 18 1041 28 SK3 -18.48 -3.07 -21.49 -3.78 6.08 20.9 1121 29 WT1 Shavish-Tanosh -18.24 -3.49 -22 -4.56 9.68 23.7 843 30 WT2 -16.72 -3.61 -22.12 -4.61 12.16 23.7 844 Mean (Groundwater samples) -16.97 -3.76 -20.3 -4.3 13.12 21.23 958.7 ACTA CARSOLOGICA 52/1 – 2023 83 croclimate conditions. In addition to higher d-excess of precipitation, some groundwater samples, including, well sample (WN5) and spring samples (SM1, SM2 and SM3) are showing higher d-excess. The reasons for higher d- excess of well and spring sample are well depth and snow melting origin of the springs. According to the isotopic composition results of the groundwater resources in the area (Table 4), the mean values of δ18O in wet and dry seasons were -3.76 to -4.3 ‰, and -16.97 to -13.12‰ and the mean δ2H value in wet and dry seasons were to respectively. The isotopic con- tent of groundwater resources in wet and dry seasons is mostly distributed between the LMWL and GMWL (Fig- ure 11) and based on location; the samples are divided into three groups, with more dispersion on dry season. The first group is the Mongasht anticline springs, which are placed on the left of the LMWL, depleted and from the rain and snow falling on the heights. These springs have a short residence time due to the conduit nature of the system and rapid movement of groundwa- ter. The second group, including the Shavish-Tanosh and Kamarderaz anticlines and the Naal-e-Asbi samples are positioned parallel to the GMWL and on or below the LMWL. In addition to the rainfall isotopic composition effect, groundwater mixing has also played a role in their isotopic characteristics. In the third group, the samples are situated on the right side of the LMWL or on the GMWL and the most of the water samples belong to the Kamarderaz anticline. Probably, due to the recharge of karst water sources with different systems (conduit and diffuse), longer water retention time in the system and more water-rock interaction, the δ18O content of these samples have been enriched. Usually the δ18O and δ2H seasonal changes are influ- enced by the inflow of melted snow in early spring (with a light isotopic index), then relatively richer rainfall in end spring and eventually the evaporation process dur- ing summer (Clark & Fritz, 1997; Edwards et al., 2004). It is evident that dry season samples in the area are more depleted than the wet season. This indicates that mostly local rainfall in winter and fracture flow from the Mon- gasht anticline recharges the karstic aquifers in the lower parts of the area and illustrates the interconnection of the water bearing structures. The isotopic composition of the groundwater in re- lation to altitude represents an indicator for locating the groundwater recharge area (Mazor, 2004). The plots of δ18O and δ2H values of the samples vs. the correspond- ing altitude in the area are presented in Figure 15. The altitude effect on isotopic composition of groundwater is expressed by the linear correlation of δ18O and δ2H with altitude as given in Equation 1 and 2. δ18O = -0.001 Altitude - 2.338 [Equation 1] δ2H = -0.008 Altitude - 8.897 [Equation 2] The local isotopic gradient shows depletion of stable isotopes by about -0.1‰ and -0.8 ‰ per 100 m elevation for δ18O and δ2H, respectively (Figure 12). The most de- pleted samples are in the Mongasht area, while the Naal- e-Asbi and Kamarderaz springs (lowest elevation) are the least depleted ones. Total dissolved solids (TDS) are a comprehensive image of common ion concentration in groundwater, and also a significant index for dissolution of geological formations, and usually the TDS of groundwater increas- es in the flow direction. In ideal conditions samples with highest TDS, are generally more enriched in 18O and 2H. KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Figure 11: Position of the isotopic composition of groundwater re- sources in the wet and dry seasons with respect to the local meteoric water line (LMWL) and the global meteoric water line (GMWL). ACTA CARSOLOGICA 52/1 – 202384 Thus, the linear arrays between end-members should be seen on plots of δ2H and δ18O vs. TDS (Welhan, 1987). Groundwater is dissolving oxygen-bearing minerals and aggravates the groundwater dissolution formations dur- ing the process of flowing (Li et al., 2021). So, the isotope exchange equilibrium equations move leftward (Equa- tion 3) and δ18O increased in accordance with the in- crease of TDS value, that is, δ18O increases in the ground- water flow direction. CaCO2 18 (calcite, dolomite and limestone) + H2O ↔ CaCO3 + H2 18° [Equation 3] To represent the ion concentration against isotope ratios, the TDS vs. δ18O depicted in Figure 13. As shown, the Mongasht samples possess more depleted isotope ratios and lower TDS than the Shavish-Tanosh, Kamarderaz and Naal-e-Asbi samples, and increasing trend of the TDS vs. δ18O in down gradient which may imply the re- charge source of the karstic aquifers from the Mongasht area. In most parts of the catchment diffuse flow occurs and recharge water travels along longer flow paths that lead to increasing residence time, TDS builds up and en- hancing water-rock interactions. Thus, discharging water in the lower reaches shows higher ion concentrations and isotope signatures. But in general, during the process of water infiltration, occurrence of isotopes attenuation re- sulted in to decrease the base flow isotope ratios in dry season. The content of δ18O in relation to TDS is more linear than that of δ2H. Such behavior may suggest water-rock interaction which affects the isotopic composition of pore fluids (Porowski, 2004). The reason for 18O shifting much more than 2H value is the fact that rock contains a large amount of oxygen, but a very small amount of hy- drogen (Bagheri et al., 2021). Of course deviation from a linear relationship (Figure 13) seems to be an evidence of other processes than dissolution which may affect the SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN Figure 12: Relationship between δ18O and elevation of the springs and wells. isotopic composition of waters in the carbonate forma- tions such as reversing the flow direction of the nearby alluvial aquifers into karstic horizons and evaporation. Based on Figure 16 (TDS vs. δ18O and δ2H) there is a good relationship between the Mongasht, Naal-e-Asbi and the remaining samples depicting the hydraulic con- nection and water transport from the Mongasht anticline into the Naal-e-Asbi, Shavish-Tanosh and Kamarderaz aquifers. The water movement from the Mongasht aqui- fer into the Naal-e-Asbi is clearly observed in the wet season. The d-excess values of water in the Mongasht anti- cline are higher than the other waters (Shavish-Tanosh and Kamarderaz anticlines and the Naal-e-Asbi) in the study area (Figure 14). The relatively higher d-excess values of the Mongasht anticline springs (SM1, SM2, and SM3) can be due to the input of snow melt water in addi- tion to precipitation. The reduction of the groundwater d-excess in by increasing the δ18O values indicates that the groundwater flow in the area is mixed with different degree of infiltrating evaporated water in the flow path. The δ18O increase with d-excess reduction supports the fact that the evaporation process affecting the isotopic signatures of oxygen and hydrogen. As shown in Figure 14a-b, (δ18O vs. d-excess), a close Figure 13: Relationship between δ18O and TDS (a), and δ2H and TDS (b), of the springs and wells in the area. ACTA CARSOLOGICA 52/1 – 2023 85 interconnection of the Mongasht anticline with the lower reaches water bearing structures, including Naal-e-Asbi, Shavish-Tanosh and Kamarderaz aquifers is observed. This association supports the role of the Mongasht terri- tory to recharge the nearby aquifers and in particular the Naal-e-Asbi in the wet and dry seasons. 3.4. CONCEPTUAL MODEL OF GROUNDWATER FLOW From the previous discussion, it is evident that an ob- jective of this study is to develop a framework to iden- tify the hydraulic connection and flow path for ground- water in the area. According to the literature review, the Mesozoic-Cenozoic carbonate complex constitutes the regional karstic aquifer and shails clays represent the regional aquitard. A geological and hydrogeologi- cal section between Mongasht anticline has been cre- ated to review the hydrogeological conceptual model of the Izeh plain using literature data, new collected data, and the geological reconstruction (Figure 3). Karst wells in Naal-e-Asbi syncline and springs represent the discharge zone of the groundwater flow coming from the movement of water from the higher elevation in the Mongasht territory towards the lower regions, includ- ing the Shavish-Tanosh, Kamarderaz and the Naal-e- Asbi aquifers (Figure 15). KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Figure 14: The relationship between d-excess and δ18O of water samples (wet (a) and dry (b) seasons). Figure 15: Geological cross section (along A-B located in Figure 1), showing flow path. ACTA CARSOLOGICA 52/1 – 202386 4. CONCLUSIONS Having in mind the fact that Iran is located at the heart of thirst of Middle East, the karst aquifers in the Za- gros area are of great economical and social importance and, thus, challenging. The presented dataset is the first compilation of stable isotope hydrological data in Izeh. The water stable isotopes data demonstrate spatial dis- tribution in various hydrogeological settings across the Izeh and provide input for future hydrogeological stud- ies and direction for groundwater management. This research was conducted to assess the hydrochemical characterization and isotopic measurements of the Izeh watershed and also to determine hydraulic relationships among the water bearing structures. The command area recharges mainly from rainfall, but the Mongasht aquifer experiences rejuvenation from rainfall as well as snow. The study results suggest that hydrochemical and isotopic data are applicable to understand the flow paths of springs (e.g., conduit flow through carbonate rocks) and the storage. The dominant cations and anions in groundwater were Ca+2, Mg+2 and HCO3 -, SO4 -2 and the sources of ions are mainly calcite and calcite-dolomite formations. The chemical concentration of ions in the samples of the Shavish-Tanosh and Kamarderaz anticlines and the Naal-e-Asbi syncline were considerably higher than the Mongasht anticline samples. The higher ion concentra- tion, is chiefly on account of the water-rock interaction and relatively longer residence time. The water type is dominantly calcium-bicarbonate, although some sam- ples illustrating Ca-SO4 facies, display, gaining of car- bonate aquifers from the within reach alluvial aquifers. The chemical composition of the principal karst springs and wells are dominantly controlled by precipitation and local rock characteristics including limestone and dolomite embracing groundwater flow. Three interre- lated processes controlling water-rock interaction, in- cluding; recharge water, dissolution and residence time. Waters flowing out of specific springs (SK3, SK4) and WK1 (well) located in the Kamarderaz anticline. These waters show a different physico-chemical compo- sition characterized by higher temperatures and electri- cal conductivity, as well as SO4 2−, Cl− and Na+ concen- trations. This particular composition probably reflects deeper groundwater flows through the saturated zone of the aquifer and longer residence times in the system, favouring a marked water -rock interaction with mainly evaporitic rocks (sulphates and halite) in the Miosen clayey body (Gachsaran formation). The positive cor- relation between Mg2+ and the ratio SO4 2−/Ca2+in some springs suggests the existence of dedolomitization pro- cesses caused by the simultaneous dissolution of gyp- sum and dolomite. There is a good positive correlation between major and certain trace elements and trace elements itself, displaying hydraulic connection among the karstic aquifers. This hydraulic connectivity is clear- ly observed between the Mongasht and Shavish-Tanosh anticlines and the Mongasht anticline and the northern limb of the Naal-e Asbi syncline and the Shavish Tanosh anticline and the southern limb of the Naal-e-Asbi syn- cline. The Mongasht anticline springs are placed on the higher altitudes with short flow path indicated depleted δ18O and δ2H isotopes. While the Kamarderaz and Shav- ish-Tanosh anticlines and the Naal-e-Asbi samples, as a result of merely rainfall recharge, diffuse flow, longer travel path, more water-rock interaction and ground- water mixing are showing relative isotopic enrichment. The combination of this gradient with the mean δ18O signature of the water drained by the springs has allowed an estimate of the average recharge altitude for each spring and karstic wells. The results are congruent with the topographic distribution of permeable areas and the position of the springs and karstic wells. In addition, they allow assumptions regarding the flow paths of groundwater drained by different springs and a possible hydrogeo- logical connection of the Izeh aquifers with the adjacent permeable outcrops. The TDS vs. δ18O indicate that the most depleted isotopic values and the lowest ion con- centration are in the Mongasht samples as compare to the Kamarderaz, Shavish-Tanosh and the Naal-e-Asbi samples, illustrating the importance of the Mongasht anticline to recharge the lower reaches of the area. The d-excess value of the Mongasht anticline sam- ples is higher than the other samples, including the Ka- marderaz and Shavish-Tanosh anticline and the Naal-e- Asbi syncline. The decreasing amount of groundwater d-excess by increasing of δ18O signature shows that the groundwater is mixed with different degrees of perco- lated evaporated recharge water in the flow direction from the Mongasht anticline to the lower reaches. The collected results from the major ions, trace elements, correlation coefficients, composite diagrams, δ18O, δ2H and d-excess values along with a hydrogeo- logical cross section reveal common origin of water, flow pattern and interconnection among the geological structures. SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN ACTA CARSOLOGICA 52/1 – 2023 87 ACKNOWLEDGMENTS The authors are so much grateful to the vice chan- cellor for the research of Shahid Chamran University of Ahvaz for providing financial assistance (grant no SCU. EG 99.618) and also would like to thank the exploita- tion deputy of Khuzestan Water and Power Authority (KWPA) for financial support and imparting necessary data to conduct this research. 5. REFERENCES Alavi, N.M., 1996. Tectonic of the Zagros, organic belt of Iran, new data and interpretation. Tectonophysics, 299: 211–238. Alemayehu, T., Leis, A., Dietzel, M., 2020. Environ- mental isotope and hydrochemical characteris- tics of groundwater in central portion of Mekelle sedimentary outlier, northern Ethiopia. Journal of African Earth Sciences, 171: 103953. https://doi. org/10.1016/j.jafrearsci.2020.103953. Alfarrah, N., Walraevens, K., 2018. Groundwater over- exploitation and seawater intrusion in coastal areas of arid and semi-arid regions. Water, 10(2): 143. https://doi.org/10.3390/w10020143. Ashjari, J., Raeisi, E., 2006. Anticline structure influences on regional flow, Zagros, Iran. Journal of cave and karst studies, 68(3): 118-129. Badaruddin, S., Werner, A.D., Morgan, L.K., 2017. Char- acteristics of active seawater intrusion Journal of Hydrology, 551: 632-647. https://doi.org/10.1016/j. jhydrol.2017.04.031. Bagheri, F., Karami, G.H., Bagheri, R., Griffioen, J., Eggenkamp, H., Jafari, H., 2021. Geochemical and multi-isotopes (δ18O, δ2H, δ13C, 3H and δ37Cl) evi- dences to karst development and flow directions in Tran’s boundary aquifer, Northeast of Iran. Ap- plied Geochemistry, 132: 105071. https://doi. org/10.1016/j.apgeochem.2021.105071. Bajjali, W., 2006. Recharge mechanism and hydrochem- istry evaluation of groundwater in the Nuaimeh area, Jordan, using environmental isotope tech- niques. Hydrogeology Journal, 14(1): 180-191. http://dx.doi.org/10.1007/s10040-004-0352-2. Bershaw, J., 2018. Controls on Deuterium Excess across Asia. Geosciences, 8(7): 257. https://doi. org/10.3390/geosciences8070257. Bhat, N.A., Jeelani, G.H., 2015. Delineation of the re- charge areas and distinguishing the sources of karst springs in Bringi watershed, Kashmir Himalayas using hydrochemistry and environmental isotopes. Journal of Earth System Science, 124: 1667–1676. https://doi.org/10.1007/s12040-015-0629-y. Blasch, K.W., Bryson, J.R., 2007. Distinguishing sources of ground water recharge by using delta 2H and del- ta18O. Ground Water, 45(3): 294– 308. https://doi. org/10.1111/j.1745-6584.2006.00289.x. Bourke, S., Hammond, M., Clohessy, S., 2015. Perth shal- low groundwater systems investigation: North Lake. http://www. water.wa.gov.au/Publication Store/ first/91255.pdf [Accessed May 2015]. Celle-Jeanton, H., Travy, Y., Blavoux, B., 2001. Isotopic typology of the precipitation in the Western Medi- terranean region at three different time scales. Geo- physical Research Letters, 28: 1215–1218. Chen, J., S, Li, L., Wang, J.Y., Barry, D.A., Sheng, X.F., Gu, W.Z., Zhao, X., Chen, L., 2004. Water resources: groundwater maintains dune landscape. Nature, 432: 459–460. https://doi.org/10.1038/432459a Chen, W., Li, H., Hou, E., Wang, S., Wang, G., Panahi, M., Li, T., Peng, T., Guo, C., Niu, C., 2018. Gis-based groundwater potential analysis using novel ensem- ble weights-of-evidence with logistic regression and functional tree models. Science of Total Environ- ment, 634: 853–867. https://doi.org/10.1016/j.scito- tenv.2018.04.055. Chihi, H., Marsily, G., Belayouni, H., Yahyaoui, H., 2015. Relationship between tectonic structures and hy- drogeochemical compartmentalization in aqui- fers: example of the Jeffara de Medenine system, south-east Tunisia. Journal of Hydrology: Region- al Studies, 4: 410–430. https://doi.org/10.1016/j. ejrh.2015.07.004. Ciner, F., Sunkari, E.D., Senbas, B.A., 2021. Geochemi- cal and Multivariate Statistical Evaluation of Trace Elements in Groundwater of Nigde Municipal- ity, South-Central Turkey: Implications for Ar- senic Contamination and Human Health Risks Assessment. Archives of Environmental Contami- nation and Toxicology, 80: 164–182. https://doi. org/10.1007/s00244-020-00759-2. Clark, I.D., Fritz, P., 1997. Environmental Isotopes in Hy- drogeology. 1st Edition. CRC Press, USA, 352 pp. Connor J.A., Paquette, S., Mchugh, T., Gie, E., Heming- way, M., Bianchi, G., 2017. Application of natural resource valuation concepts for development of sus- KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN ACTA CARSOLOGICA 52/1 – 202388 SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN tainable remediation plans for groundwater. Journal of Environmental Management, 204: 721. https:// doi.org/10.1016/j.jenvman.2017.03.053. Coplen, T. B., 1993, 'Uses of Environmental Isotopes', in: Alley, W. M. (ed.), Regional Water Quality, Van Nostrand Reinhold, pp. 227–254. Dansgaard, W., White, J.W., Johnsen, S.J., 1989. The abrupt termination of the Younger Dryas climate event. Nature, 339: 532–534. Dimitriou, E., Tsintza, P., 2015. Hydrogeologic Investiga- tions in Western Crete by Using Isotopic Analyses and GIS Techniques. Journal of Water Resource and Protection, 7: 923-937. http://dx.doi.org/10.4236/ jwarp.2015.712076. Doctor, D.H. Jr, Alexander, C.E. Jr, Petric, M., Kogov- sek, J., 2006. Quantification of karst aquifer dis- charge components during storm events through end-member mixing analysis using natural chem- istry and stable isotopes as tracers. Hydrogeology Journal, 14(7): 1171-1191. https://doi.org/10.1007/ s10040-006-0031-6. Doveri, M., Menichini, M., Cerrina Feroni, A., 2013. Sta- ble water isotopes as fundamental tool in karst aqui- fer studies: some results from isotopic applications in the Apuan Alps carbonatic complexes (NW Tus- cany). Italian Journal of Engineering Geology and Environment, 1: 33–50. http://dx.doi.org/10.4408/ IJEGE.2013-01.O-03. Edmunds, W.M., Ma, J.Z., Aeschbach-Hertig, W., Kipfer, R., Darbyshire, D.P.F., 2006. Groundwater recharge history and hydrogeochemical evolution in the Minqin Basin, North West China. Applied Geo- chemistry, 21(12): 2148–2170. Edwards, T.W.D., Wolfe, B.B., Gibson, J.J., Hammarlund, D., 2004. Use of water isotope tracers in high-lati- tude hydrology and paleohydrology. In: Pienitz, R., Douglas, M.S.V., Smol, J.P. (Eds.), Long-term Envi- ronmental Change in Arctic and Antarctic Lakes. Springer, Dordretch, pp. 187–207. Emblanch, C., Zuppi, G.M., Mudry, J., Blavoux, B., Ba- tiot, C., 2003. Carbon 13 of TDIC to quantify the role of the unsaturated zone: the example of the Vaucluse karst systems (Southeastern France). Jour- nal of Hydrology, 279(1-4): 262–274. http://dx.doi. org/10.1016/S0022-1694 (03)00180-X. Fairchild, I.J., Borsato, A., Tooth, A.F., Frisia, S., Hawkes- worth, C.J., Huang, Y, McDermott F.P., Spiro, B., 2000. Controls on trace element (Sr–Mg) composi- tions of carbonate cave waters: implications for spe- leothem climatic records. Chemical Geology, 166: 255–269. Farid, I., Abbas, M.H.H., Bassouny, M., 2020. Indirect impacts of irrigation with low quality water on the environmental safety. Egyptian Journal of Soil Sci- ence, 60(1):1-15. https:// doi. Org/ 10. 21608/ ejss. 2019. 15434. 1294. Ford, D.C., Williams, P.W., 1989. Karst Geomorphology and Hydrology. Unwin Hyman, London: Chapman and Hall, 601 pp. Ford, D.C., Williams, P.W., 2007. Karst Hydrogeology and Geomorphology. John Wiley, Chichester, 562 pp. https://doi.org/10.1002/9781118684986 Frohlich, K., Gibson, J.J., 2015. Aggarwal, P. Deuterium Excess in Precipitation and Its Climatological Significance. Available online: http://www.iaea.org/inis/ collection/NCLCollectionStore/_Public/ 34/017/34017972.pdf (Accessed 12 March 2015). Gates, J.B., Edmunds, W.M., Darling, W.G., Pang, J., Ma, Z., Young, A.A., 2008. Conceptual model of recharge to southeastern Badain Jaran Desert groundwa- ter and lakes from environmental tracers. Applied Geochemistry, 23(12): 3519– 3534. http://dx.doi. org/10.1016/j.apgeochem.2008.07.019. Gibbs, R.J., 1970. Mechanisms controlling world water chemistry. Science, 17: 1088–1090. Goldscheider, N., Andreo, B., 2007. The geological and geomorphological framework. In: Goldscheider, N., Drew, D. (Eds.), Methods in karst hydrogeology. In- ternational Contribution to Hydrogeology, IAH, vol 26. Taylor and Francis/Balkema, London, pp. 9–23. Haldar, K., Kujawa-Roeleveld, K., Dey, P., 2020. Spatio- temporal variations in chemical-physical water quality parameters influencing water reuse for irri- gated agriculture in tropical urbanized deltas. Sci- ence of the Total Environment, 708: 134559. https:// doi.o rg/1 0.1 016/j. scito tenv. 2019. 134559. Hatipoglu-Bagci, Z., Sazan, M.S., 2014. Characteristics of karst springs in Aydıncık (Mersin, Turkey), based on recession curves and hydrochemical and isoto- pic parameters. Quarterly Journal of Engineering Geology and Hydrogeology, 47(1): 89-99. https:// doi.org/10.1144/qjegh2013-074. Helena, B., Pardo, R., Vega, M., Barrado, E., Fernandez, J.M., Fernandez, L., 2000. Temporal evolution of groundwater composition in an alluvial (Pisuerga river, Spain) by principal component analysis. Wa- ter Research, 34: 807–816. Heydarizad, M., Minaei, F., Eskandari Mayvan, J., Mofidi, A., Minaei, M., 2021. Spatial distribution of stable isotopes (18O and 2H) in precipitation and ground- water in Iran, Isotopes in Environmental and Health Studies, 57(4): 400-419. https://doi.org/10.1080/102 56016.2021.1924167. Hounslow, A.W., 1995. Water Quality Data: Analysis and Interpretation, CRC Lewis Publishers, Boca Raton, pp. 86–87. ACTA CARSOLOGICA 52/1 – 2023 89 KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN Jebreen, H., Banning, A., Wohnlich, S., Niedermayr, A., Ghanem, M., Wisotzky, F., 2018. The Influence of Karst Aquifer Mineralogy and Geochemistry on Groundwater Characteristics: West Bank, Pales- tine. Jornal Water, 10: 1829. https://doi.org/10.3390/ w10121829. Jiang, L., Sui, M., Fan, Y., Su, H., Xue, Y., Zhong, S., 2021. Micro-gas column assisted laser induced breakdown spectroscopy (MGC-LIBS): A metal elements detec- tion method for bulk water in-situ analysis. Spec- trochimica Acta Part B: Atomic Spectroscopy, 177: 106065. https://doi.org/10.1016/j.sab.2021.106065. Johnsen, S.J., Dansgaard, W., White, J.W.C., 1989. The origin of Arctic precipitation under present and gla- cial conditions. Tellus B, 41: 452–468. Jouzel, J., Stievenard, M., Johnsen, S.J., Landais, A., Mas- son-Delmotte, V., Sveinbjornsdottir, A., Vimeux, F., von Grafenstein, U., White J.W.C., 2007. The GRIP deuteriumexcess record. Quaternary Science Re- views 26(1–2): 1–17. https://doi.org/10.1016/j.qua- scirev.2006.07.015. Kalantari, N., Pawar, N.J., Keshavarzi, M.R., 2009. Wa- ter resource management in the intermountain Izeh Plain, Southwest of Iran. Journal of Mountain Sci- ence, 6: 25–41. https://doi.org/10.1007/s11629-009- 0212-6. Krienen, L., Heuser, M., Hobig, N., 2017. Hydrogeo- logical and hydrochemical characterization of two karstic discharge areas in San Luis Potosí, Mexico. Environmental Earth Sciences, 76: 825. https://doi. org/10.1007/s12665-017-7166-8. Langelier, W.F., Ludwig, H.F., 1942. Graphic method for indicating the mineral character of natural water. Journal - American Water Works Association, 34(3): 335–352. Lewinska-Preis, L., Szram, E., Fabiańska, M.J., 2021. Se- lected ions and major and trace elements as contam- inants in coal-waste dump water from the Lower and Upper Silesian Coal Basins (Poland). International Journal of Coal Science & Technology, 8: 790–814. https://doi.org/10.1007/s40789-021-00421-9. Li, X., Han, G., Liu, M., Liu, J., Zhang, Q., Qu, R., 2021. Potassium and its isotope behaviour during chemi- cal weathering in a tropical catchment affected by evaporite dissolution, Geochimica et Cosmochi- mica Acta, 316: 105-121. https://doi.org/10.1016/j. gca.2021.10.009. Liu, P., Yang, M., Sun, Y., 2019. Hydro-geochemical pro- cesses of the deep Ordovician groundwater in a coal mining area, Xuzhou, China. Hydrogeology, 27(6): 2231-2244. https://doi.org/ 10.1007/s10040-019- 01991-4. Ma, J.Z., He, J.H., Qi, S., Zhu, G.F., Zhao, W., Edmunds, W.M., Zhaom, Y.P., 2013. Groundwater recharge and evolution in the Dunhuang Basin, northwest- ern China. Applied Geochemistry, 28:19–31. Mahlknecht, J., Garfias-Solis, J., Aravena, R., Tesch, R., 2006. Geochemical and isotopic investigations on groundwater residence time and flow in the Inde- pendence Basin, Mexico. Journal of Hydrology, 324(1-4): 283–300. http://dx.doi.org/10.1016/j.jhy- drol.2005.09.021. Makhloufi, Y., Rusillon, E., Brentini, M., Moscariello, A., Meyer, M., Samankassou, E., 2018. Dolomitization of the Upper Jurassic carbonate rocks in the Gene- va Basin, Switzerland and France. Swiss Journal of Geosciences, 111: 475–500. https://doi.org/10.1007/ s00015-018-0311-x. Marfia, A.M., Krishnamurthy, R.V., Atekwana, E.A., Panton, W.F., 2004. Isotopic and geochemical evo- lution of groundwater and surface waters in a karst-dominated geological setting: a case study from Belize, Central America. Applied Geochem- istry, 19: 937–946. https://doi.org/10.1016/j.apgeo- chem.2003.10.013. Masson-Delmotte, V., Jouzel, J., Landais, A., Stievenard, M., Johnsen, S.J., White, J.W.C., Werner, M., Svein- bjornsdottir, A., Fuhrer, K., 2005. GRIP deuterium excess reveals rapid and orbital-scale changes in Greenland moisture origin. Science, 309(1): 118– 121. Mazor, E., 2004. Chemical and isotopic groundwater hy- drology, 3rd ed. Weizmann Institute of Science Re- hovot, New York, 465pp. Milanovic, P.T., 1981. Karst hydrogeology. Water Re- sources publications, Littleton, 434 pp. Mokadem, N., Dennis, R., Dennis, I., 2021. Hydrochemi- cal and stable isotope data of water in karst aquifers during normal flow in South Africa. Environmen- tal Earth Sciences, 80: 519. https://doi.org/10.1007/ s12665-021-09845-7. Moral, F., Cruz-Sanjulian, J.J., Olias, M., 2008. Geochem- ical evolution of groundwater in the carbonate aqui- fers of Sierra de Segura (Betic Cordillera, southern Spain). Journal of Hydrology, 360: 281– 296. Morsy, K.M., Morsy, A.M., Hassan, A.E., 2018. Ground- water sustainability: opportunity out of threat. Groundwater for sustainable development, 7: 277– 285. Murillo, R.S., Brooks, E., Elliot, J.W., Bolla, J., 2015. Iso- tope hydrology and baseflow geochemistry in natu- ral and human-altered watersheds in the inland Pacific Northwest, USA. Isotopes in Environmental and Health Studies, 51(2): 231–254. https://doi.org/ 10.1080/10256016.2015.1008468. Nader, F.H., Swennen, R., Ottenburgs, R., 2003. Karst- ACTA CARSOLOGICA 52/1 – 202390 SSESSMENT OF THE HYDROGEOCHEMICAL AND ISOTOPIC CHARACTERIZATION AND HYDRAULIC BEHAVIOR OF THE IZEH COMPLEX KARSTIC AREA, KHUZESTAN PROVINCE, SOUTHWEST IRAN meteoric dedolomitization in Jurassic carbonates, Lebanon. Geologica Belgica, 6: 3–23. Narany, S.T., Ramli, M.F., Aris, A.Z., Sulaiman, W.N.A., Juahir, H., Fakharian, K., 2014. Identification of the hydrogeochemical processes in groundwater using classic integrated geochemical methods and geo- statistical techniques in Amol-Babol plain, Iran. Scientific World Journal, 2014: 1–15. https://doi. org/10.1155/2014/419058. Nassery, H.R., Alijani, F., Nakhaei, M., 2013. The com- parison of hydrodynamic characteristics of karst aquifers: application on two karst formations in Zagros (Asmari and Ilam-Sarvak), southwest Iran. Arabian Journal of Geosciences, 7(11): 4809-4818. http://dx.doi.org/10.1007%2Fs12517-013-1017-z. Negrel, Ph, Petelet-Giraud, E., 2005. Strontium isotopes as tracers of groundwater induced floods: the Somme case study (France). Journal of Hydrology, 305: 99. 119. https://doi.org/10.1016/j.jhydrol.2004.08.031. Porowski, A., 2004. Isotopic evidence of the origin of mineralized waters from the Central Carpathian Synclinorium, SE Poland. Environmental Earth Sci- ences, 46(5): 661-669.http://dx.doi.org/10.1007/ s00254-004-1005-4. Pracny, P., Faimon, J., Vsiansky, D., 2017. Evolution of Mg/Ca Ratios during Limestone Dissolution un- der Epikarstic Conditions. Aquatic Geochemistry, 23: 119–139. https://doi.org/10.1007/s10498-017- 9313-y. Pratama, A.D., Dwiputra, D.S., Nurkholis, A., Haryono, E., Cahyadi, A., Fauzan, R., 2021. Factors Affecting Hydrochemistry of Karst Springs and their Rela- tionship to Aquifer Development. Environmental Processes, 8: 1379–1413. https://doi.org/10.1007/ s40710-021-00547-7. Rademacher, L.K., Clark, J.F., Boles, J.R., 2003. Ground- water residence times and flow paths in fractured rock determined using environmental tracers in the Mission tunnel: Santa Barbara County, California, USA. Environ Geol 43: 557–567. Rajmohan, N, Elango, L., 2004. Identification and evolu- tion of hydrogeochemical processes in the ground- water environment in an area of the Palar and Cheyyar river basins, southern India. Environmen- tal Geology, 46(1): 47–61. https://doi.org/10.1007/ s00254-004-1012-5. Rehman, F., Cheema, T., Azeem, T., 2019. Groundwater quality of Sargodha city and its suitability for do- mestic and irrigation purpose. Fresenius Environ- mental Bulletin, 28(11): 7695–7700. Ren, M., Jones, B., 2017. Spatial variations in the stoi- chiometry and geochemistry of Miocene dolomite from Grand Cay-man: implications for the origin of island dolostone. Sedimentary Geology, 348: 69–93. https://doi.org/10.1016/j.sedgeo.2016.12.001. Rodgers, P., Soulsby, C., Waldron, S., Tetzlaff, D., 2005. Using stable isotope tracers to assess hydrological flow paths, residence times and landscape influ- ences in a nested mesoscale catchment. Hydrology and Earth System Sciences, 9: 139–155. https://doi. org/10.5194/hess-9-139-2005. Rudy, L., Maheu, C., Korner, A., Lebel, S., Gelinas, C., 2020. The FCR-1: Initial validation of a single-item measure of fear of cancer recurrence. Psychooncol- ogy, 29(4): 788-795. https://doi.org/10.1002/ pon.5350. Ryu, J.S., Lee, K.S., Chang, H.W, 2007. Hydrogeochemical and isotopic investigations of the Han River basin, South Korea. Journal of Hydrology, 345(1-2): 50– 60. https://doi.org/10.1016/j.jhydrol.2007.08.001 Scanlon, R., Healy, W., Cook, G., 2002. Choosing appro- priate techniques for quantifying groundwater re- charge. Hydrogeology. Journal, 10(1): 18–39. http:// dx.doi.org/10.1007/s10040-001-0176-2. Setiawan, T., Yoseph, C.S.S.B., Alam, S., Haryono, E., Hendarmawan, I., 2020. Hydrochemical and en- vironmental isotopes analysis for characterizing a complex karst hydrogeological system of Watuputih area, Rembang, Central Java, Indonesia, Hydroge- ology Journal, 28(5): 1635-1659. https://ui.adsabs. harvard.edu/link_gateway/2020HydJ...28.1635S/ doi:10.1007/s10040-020-02128-8. Singh, M., Kumar, S., Kumar, B., Singh, S., Singh, I.B., 2013. Investigation on the hydrodynamics of Ganga alluvial plain using environmental isotopes: a case study of the Gomati River basin, northern India. Hydrogeology Journal, 21: 687–700. https://doi. org/10.1007/s10040-013-0958-3. Slabe, T., Liu, H., 2009. Significant subsoil rock forms. In: Ginés, A., Knez, M., Slabe, T., Dreybrodt, W., (Eds), Karst rock features, Karren sculpturing. Carsologi- ca, 9. ZRC Publishing, Ljubljana, pp 123−137. Srivastava, S.K., Ramanathan, A.L., 2008. Geochemical assessment of groundwater quality in vicinity of Bhalswa landfill, Delhi, India, using graphical and multivariate statistical methods. Environmental Ge- ology, 53: 1509–1528. Stocklin, J., 1974. Evolution of the continental margins bounding a former Southern Tethys. In:Burk, C.A., Drake, C.L.(Eds.), The Geology of Continental Mar- gins. Berlin, Springer, pp. 873-887. Sun, Z., Ma, R., Wang, Y., Ma, T., Liu, Y., 2016. Using isotopic, hydrogeochemical-tracer and temperature data to characterize recharge and flow paths in a complex karst groundwater flow system in north- ACTA CARSOLOGICA 52/1 – 2023 91 KALANTARI NASROLLAH, SAJADI ZAHRA, CHARCHI ABBAS & MOUSAVI SEYYED SAJEDIN ern China. Hydrogeology Journal, 24: 1393–1412. https://doi.org/10.1007/s10040-016-1390-2. Tang, L., Zhao, Y., Zhang, S., Sun, T., KaiHu, L., Ming, X., Sheng, Y., Zeng, T., 2021. Origin and evolution of a porphyry-breccia system: Evidence from zircon U-Pb, molybdenite Re-Os geochronology, in situ sulfur isotope and trace elements of the Qiyugou deposit, China. Gondwana Research, 89: 88-104. Tian, L., Gao, Y., Yang, G., Schwartz, B., Cai, B., Lei, G., Shi, G., Ray, C., Sok, S., Martinez, E., Li, Y., Wu, H., 2021. The evolution of hydrochemical and isoto- pic signatures from precipitation, surface water to groundwater in a typical karst watershed, Central Texas, USA, Isotopes in Environmental and Health Studies, 57(5): 492-515. https://doi.org/10.1080/102 56016.2021.1948410. Tillman, F.D., Oki, D.S., Johnson, A.G., Barberm, L.B., Beisner, K.R., 2014. Investigation of geochemical indicators to evaluate the connection between in- land and coastal groundwater systems near Kalo- ko-Honoko-hau National Historical Park, Hawai‘i. Applied Geochemistry, 51: 278–292. https://doi. org/10.1016/j.apgeochem.2014.10.003. Valdes, D., Dupont, J.P., Laignel, B., Ogier, S., Leboulanger, T., Mahler, B.J., 2007. A spatial analysis of structural controls on karst groundwater geochemistry at a regional scale. Journal of Hydrology, 340: 244–255. https://doi.org/10.1016/j.jhydrol.2007.04.014. Ventura-Houle, R., Guevara-Mansilla, O., Requena-Lara, G., 2021. Hydrochemistry, δD and δ18O to explain the distribution of water quality in a karst setting in the semi-arid region of Northeast Mexico. En- vironmental Earth Sciences, 80(1): 6. https://doi. org/10.1007/s12665-020-09310. Vreca, P., Kern, Z., 2021. Use of Water Isotopes in Hydro- logical Processes. Water, 12(8): 2227. Wang, Y., Song, X., Li, B., 2018. Temporal variation in groundwater hydrochemistry driven by natural and anthropogenic processes at a reclaimed water irriga- tion region. Hydrology Research, 49(5):1652–1668. https://doi.org/10.2166/nh.2018.123. Welhan, J.A., 1987. Stable isotope hydrology. In: Kyser, T.K., (Ed.), Stable Isotope Geochemistry of Low Temperature Processes. Short Course Handbook, 13. Mineralogical Association of Canada, Saska- toon, pp. 129–157. White, W.B., 2015. Chemistry and karst. Acta Carso- logica, 44(3): 349–362. https://doi.org/10.3986/ ac.v44i3.1896. Yasin, D., Kargın, M., 2021. Hydrogeochemical and isotopic characteristics of water resources in Cu- buk-Meliksah (Ankara/Turkey). Environmental Earth Science, 80: 513 https://doi.org/10.1007/ s12665-021-09813-1. Yuan, R., Wang, S., Wang, V., Song, X., Tang, C., 2017. Changes in flow and chemistry of groundwater heav- ily affected by human impacts in the Baiyangdian catchment of the North China Plain. Environmen- tal Earth Sciences, 76(16): 571. https://link.springer. com/article/10.1007%2Fs12665-017-6918-9. Zaidi, F.K., Nazzal, Y., Jafri, M.K., Naeem, M., Ahmed, I., 2015. Reverse ion exchange as a major pro- cess controlling the groundwater chemistry in an arid environment: a case study from northwestern Saudi Arabia. Environmental Monitoring and As- sessment, 187(10): 607. https://doi.org/10. 1007/ s10661-015-4828-4. Zanchi, A., Zanchetta, S., Berr, F., Mattei, M., Garzanti, E., Molyneux, S., Sabouri, J., 2009. The Eo-Cim- merian (Late? Triassic) orogeny in North Iran. In: Brunet, M.F.; Wilmsen, F.; Granath, J.W., (Eds.), South Caspian to Central Iran basins. Geological Society Special Publications, 312. Geological So- ciety of London, London, pp. 31-55. https://doi.1. org/10.1144/SP312.3. Zhang, W., Li, L., Wang, X., Xing, W., Li, R., Yang, T., Lv, D., 2020. Role of trace elements in anaerobic digestion of food waste: Process stability, recovery from vola- tile fatty acid inhibition and microbial community dynamics. Bioresource Technology, 315: 123796. https://doi.org/10.1016/j.biortech.2020.123796. Zhou, J., Zhang, Y., Zhou, A., Liu, C., Cai, H., Liu, Y., 2016. Application of hydrochemistry and stable isotopes (δ34S, δ18O and δ37Cl) to trace natural and anthro- pogenic influences on the quality of groundwater in the piedmont region, Shijiazhuang, China. Applied Geochemistry, 71: 63–72. https://doi.org/10.1016/j. apgeochem. 2016.05.018. CONFLICT OF INTEREST The authors have no conflicts of interest to declare. All co-authors have seen and agree with the contents of the manuscript and there is no financial interest to report. We certify that the submission is original work and is not under review at any other publication. Author names: Nasrollah Kalantari, Zahra Sajadii, Abbas Charchi and Seyyed Sajedin Mousavi. ACTA CARSOLOGICA 52/1 – 202392