Geo-genic arsenic contamination in the Kerman Cenozoic Magmatic Arc, Kerman, Iran: Implications for the source identification and regional analysis

Accepted Manuscript Geo-genic arsenic contamination in the Kerman Cenozoic Magmatic Arc, Kerman, Iran: Implications for the source identification and regional analysis Mehdi Khorasanipour, Esmat Esmaeilzadeh PII:

S0883-2927(15)30021-4

DOI:

10.1016/j.apgeochem.2015.08.004

Reference:

AG 3532

To appear in:

Applied Geochemistry

Received Date: 24 March 2015 Revised Date:

14 July 2015

Accepted Date: 6 August 2015

Please cite this article as: Khorasanipour, M., Esmaeilzadeh, E., Geo-genic arsenic contamination in the Kerman Cenozoic Magmatic Arc, Kerman, Iran: Implications for the source identification and regional analysis, Applied Geochemistry (2015), doi: 10.1016/j.apgeochem.2015.08.004. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Geo-genic arsenic contamination in the Kerman Cenozoic Magmatic Arc, Kerman, Iran:

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Implications for the source identification and regional analysis

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Mehdi Khorasanipour a, Esmat Esmaeilzadeh b

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a

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Iran.

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b

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Corresponding author email address: [email protected]

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Department of Geology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman,

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Research and Development Division, Sarcheshmeh Copper Complex, Kerman, Iran.

[email protected]

Abstract

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Iranian Volcano-Plutonic Copper belt. Arsenic contamination from geo-genic source is one of

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the most important environmental concerns in this area. The main objective of this study was to

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determine the role of geothermal related activities in the arsenic contamination. For this purpose,

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the old and active geological indicators of the geothermal activities were investigated through the

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quaternary travertine deposits and the present hydrothermal warm springs, respectively. Results

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showed that arsenic is highly concentrated (ranged mainly from 12,400 to 90,500 mg/Kg) in the

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reddish-brown deposits of the travertine rocks. Arsenic showed geochemical association with

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Co, Cu, Mo, Sb, Tl, Se, Fe, and Mn in these samples. Yukonite [Ca7Fe3+12

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(AsO4)10(OH)2015H2O], a rare Ca ferric arsenate hydrous mineral, was the only As-bearing

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mineral identified in the reddish-brown deposits of the travertine rocks. Arsenic concentration in

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the hydrothermal warm springs (<38 ºC) ranged from 15,900 to 30,500 µg/L (the dominant form

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was as H3AsO30). Hydrothermal contaminated waters also were characterized by Na-Cl type and

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high values of EC (11,400 µs/cm), TDS (8,300 mg/L), B (42,700 µg/L), Li (3,000 µg/L), Fe (900

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µg/L), Sb (82.8 µg/L), and Si (47,000 µg/L) and natural anomalies of Cs, Mn, Mo, Rb, Se, and

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Tl. The obtained hydro-geochemical results are similar to those reported in the literature for

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worldwide hydrothermal waters. Although, natural attenuation processes, such as adsorption/co-

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precipitation or mixing/dilution, reduce most of the arsenic contamination from hydrothermal

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Kerman Cenozoic Magmatic Arc (KCMA) is located in the southeastern part of the Central

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source, but some urban and rural communities are still depending on the arsenic contaminated

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waters with arsenic concentrations higher than recommended values for drinking or irrigation, a

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subject that increases the risk of arsenic-related diseases in some areas of the Kerman province.

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Key words: Arsenic, Kerman Cenozoic Magmatic Arc, Geothermal activities

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1. Introduction

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Arsenic is the most important natural-occurring metalloid with the highest contamination

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potential among toxic trace elements in the environment (Iskandar et al., 2012; Ahn and Cho,

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2013; Bundschuh et al., 2013; Simsek, 2013; Barats et al., 2014; Özkul et al., 2014). Naturally

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surface and groundwater arsenic contamination, caused global widespread human diseases such

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as skin lesions, hyperkeratosis, melanosis and different forms of carcinoma and lung cancer

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(Hopenhayn-Rich et al., 1996; Kurttio et al., 1999; Tondel et al., 1999; Smedley and Kinniburgh,

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2005). Today, drinking or domestic usage of groundwater stained with geo-genic source are the

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major route of arsenic exposure in the contaminated areas (e.g. Heinrichs and Udluft, 1999; Berg

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et al., 2001; Gurzau and Gurzau, 2001). Health problems is possible when the arsenic

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concentration exceeds in drinking water from the World Health Organization (WHO) drinking

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water guideline (10 µg/L).

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The hydro-geochemical behavior of arsenic differs significantly from the other

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potentially toxic metals and metalloids. For example, the mobilization of heavy metals is

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controlled by pH and Eh conditions and occurs primarily in low pH, oxidizing environments

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(Lottermoser, 2003), while As is relatively mobile over a wide range of pH (i.e. extremely acid

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to alkaline) and redox conditions (e.g. Masscheleyn et al., 1991; Roddick-Lanzilotta et al., 2002)

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According to Smedley and Kinniburgh (2002), the natural contamination sources of

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arsenic have been attributed to several geochemical processes. The contamination of natural

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drainage systems due to the geologically based arsenic, especially as a result of geothermal

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activities in the volcanic zones, is one of the most important natural sources of this element

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(Nimick et al., 1998; Horton et al., 2001; Smedley and Kinniburgh, 2002; Webster and 2

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Nordstrom, 2003; Cumbal et al., 2010; Baba and Sözbilir, 2012; López et al., 2012; Bundschuh

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et al., 2013; Li et a., 2014; Sengupta et al., 2014; Bundschuh and Maity, 2105). Geothermal

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process has the potential to transport As beyond the boundary of the geothermal field, where As

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participates in the various chemical and biochemical reactions (Ferguson and Gavis, 1972). The southeastern part of the Central Iranian Volcano-Plutonic Copper belt, the so-called

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Dahaj-Sardouieh subdivision or Kerman Cenozoic Magmatic Arc (KCMA; Shafiei et al., 2009),

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with 450 km in length and 60 to 80 km wide, is the host for most important Cu porphyry deposits

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such as Sarcheshmeh, Midouk, Darezar, Chehargonbad and Iju (Asadi et al., 2014). In spite of

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the economic importance, this area is faced with the serious obstacle about the geo-genic

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contamination sources, such as the source and environmental health effects of the surface and

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subsurface arsenic contaminated waters that are used for drinking, domestic or irrigation

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purposes. Arsenic contaminations higher than the WHO drinking water guideline (10 µg/L) have

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been reported in the groundwater of the Rafsanjsn (Khajehpour, 2007; Ebrahimi, 2009), Bardsir

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(Mirzaie, 2012; Abbasnejad et al., 2013), and Rayen (Pazand and Javanshir, 2103) plains, which

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are located in/or adjacent to the Kerman Cenozoic magmatic belt. For example, Arsenic

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concentrations ranging from 1.3 to 464.5 µg/L, and <0.5-25,000 µg/L have been reported for the

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Bardsir (Abbasnejad et al., 2103) and Rayen (Pazand and Javanshir, 2103) plains, respectively.

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Different mechanisms have been proposed by previous works for the possible source of the

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arsenic contamination. The main objective of this study is to investigate the role of geothermal

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activities in the geo-genic arsenic contamination of the Kerman Cenozoic Magmatic Arc.

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2. Geo-environmental characteristics of the study area The Kerman Cenozoic Magmatic Arc (KCMA) is located in the southeastern part of the

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Central Iranian volcano-plutonic copper belt, the so called Cenozoic Urumieh-Dokhtar magmatic

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belt (Fig. 1). The volcano-plutonic belt of Iran, situated in the Alpine-Himalayan orogenic

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system, is a part of a huge copper belt, several thousand kilometers long, extending from the East

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Serbia via Bulgaria, Turkey and Iran, to Afghanistan and Pakistan (Nedimovic, 1973; Shafiei et

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al., 2009; Asadi et al., 2014). The major geological features of this area are related to the

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metallogenetic features and magmatic activities, particularly the distribution of ultrabasic and

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basic rocks, volcanic-sedimentary complexes and synorogenic intrusives (Nedimovic, 1973).

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Undoubtedly, the Eocene volcanic-sedimentary complex represents the most impressive and the

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most interesting geological feature in the Kerman province (Fig. 1). The most important porphyry copper deposits of Iran, such as the Sarcheshmeh mine, are

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located in the Kerman Cenozoic Volcano-Plutonic Arc. These deposits are associated with the

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calc-alkaline intrusive rocks or stocks (Asadi et al., 2014). The magmatic belt is elongated in a

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northwest-southeast direction; its maximum length is about 550 km, and the width varies

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between 100 and 150 km (Nedimovic, 1973).

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Most areas of the Kerman volcano-plutonic belt have typical mountainous topography,

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with several mountain ranges with general northwest-southeast trend, separated by broad

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depressions and basins. The basins and depressions are usually up to, or more than, a hundred

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kilometers long and 20-40 km wide (Nedimovic, 1973). The Anar-Rafsanjan-Bardsir basin is one

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of the biggest of these basins (Fig. 1). The large concentration of urban and rural settlements are

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in the Rafsanjan, Kerman, Bardsir and Sirjan-Baft areas, as well as in the Sabzevaran plain. The

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altitude of most of the basins is usually more than 1500m. The drainage network is well

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developed and numerous seasonal streams transporting large amounts of material from the

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highlands and depositing them in the basins. In this area, the perennial streams and rivers, except

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in their uppermost courses in the mountains or during the winter and early springs, are not

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common. All streams are turbulent during prolonged rains or flash storms (Nedimovic, 1973).

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Springs, except in some of the mountains, are few, and present mostly along faults of geological

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boundaries. According to research by Abbasnejad et al. (2013), the aquifers of the plains in this

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area are mainly composed of the alluvial sediments and predominantly recharge by the high

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mountains. The thickness of sediments increases from the mountain front towards the center of

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the plain. For example, the alluvial aquifer of the Bardsir plain is mainly composed of coarse

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alluvial sediments which gradually become finer towards the center and deposited from the

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erosion of volcanic rocks at southern mountains (Abbasnejad et al., 2013).

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Due to the expanding of the study area, the micro-climates are also varied but the general

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climate is typical for continental and arid to semiarid environments. For example, the summers

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are long and hot, and temperatures reach 45-50 °C for prolonged periods in some areas such as

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Sabzevaran plain. By contrast, the Sarcheshmeh area has a semi-arid climate with an annual

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temperature between -20 and 32 ºC, a mean rainfall of 440 mm, and annual evaporation of about 4

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1,170 mm (Khorasanipour et al., 2011). Most of the precipitation is in the winter and early

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springs, usually as snow at the higher elevations, or as prolonged, sometimes stormy rains in the

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basins.

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As noted earlier, groundwater arsenic contamination, higher than the recommended values for drinking water (>10µgL-1, WHO, 2006; U.S.EPA, 2009), had been reported in the

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several parts of the Kerman volcano-plutonic belt. The source of the arsenic contamination is a

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serious controversial issues related to the Kerman volcano-plutonic belt. Previous studies in the

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Kerman Cenozoic Magmatic Arc mainly focused mainly on the arsenic concentration in the

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groundwaters of the Bardisr (Mirzaie, 2012; Abbasnejad et al., 2103), Rafsanjan (Khajehpour,

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2007; Ebrahimi, 2009) and Rayen plains (Pazand and Javanshir, 2103). They showed As

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concentration is associated with (1) decomposition of sulfides present in mountainous volcanic

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rocks; (2) release of arsenic from Fe hydroxides in the pH values higher than 8; (3) reduction of

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arsenic bearing iron oxides/oxyhydroxides; and (4) transferring of As into the water system

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during water–acidic volcanic rock interactions. Hydrothermal source of As only noted as a

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possible source (Abbasnejad et al., 2103). Mining and industrial related activities, especially in

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the Sarcheshmeh copper industrial complex (Fig. 2), the largest Cu producer in Iran, are other

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possible sources of the As.

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3. Material and methods

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Based on the primary strategy, we focused on the geothermal related processes as one of

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the most important possible geo-genic contamination sources of arsenic. For this purpose, old

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and active geological signs of the geothermal activities were investigated through travertine

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rocks and the hydrothermal warm springs, respectively. More details descripted as follow:

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3.1. Travertine rocks and their related deposits During the field studies, a huge precipitations of travertine rocks were observed at the

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volcano-plutonic belt, especially around the mineralized areas and volcanic settings. These

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precipitations are widely distributed as a calcareous terraces zone in north of the Sarcheshmeh

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copper mine and in the upper parts of the Rafsanjan catchment basin (Fig. 2). The calcareous

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terraces were also observed at the volcano-plutonic areas in the south and southeastern parts of 5

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the Bardsir plain. These calcareous terraces and recent alluvium are the main sedimentary units

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formed in quaternary (Dimitrijevic, 1973). Filed works also showed that, the travertine rocks

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were accompanied with the reddish-brown deposits with different thicknesses (Fig. 3). The

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morphology of these layers in the travertine rocks shows the syngenetic precipitation of these

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two deposits. According to the filed indicators, sixteen solid samples were collected from

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calcareous terraces and their related reddish-brown layers, separately (Fig. 2 and 4). The total

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contents of 45 elements were determined using ICP-MS/OES after microwave multi-acid

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digestion at the Labwest Laboratory, Perth, Australia. The microwave technique for the digestion

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process was used as a sealed pressure vessel, effectively a bomb digestion, which enables the

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process to proceed at high pressures and temperatures. An advantage of the sealed vessel

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technique is that it retains volatile elements such as arsenic during the digestion. The vessels are

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cooled to near ambient temperature before being opened, which lowers the potential of losses.

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3.2. Hydrothermal waters

Several active hydrothermal warm springs and cold mineral waters were found associated

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with the travertine deposits in the Kerman volcano-plutonic belt. These water resources are

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situated in the south and southwestern parts of the Bardsir plain. Lalezar and Khodadadi are the

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most famous of these hydrothermal warm springs (Fig. 4). The discharge rate of these warm

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springs varies according to the seasonal changes. The Ab-bakhsh River is the most important

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seasonal drainage in the Bardsir Plain. This river flows from the south creates a large alluvial fan

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which occupies about one-third of the plain. As shown in figure 4, the Ab-Bakhsha catchment

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basin is originated from the volcano-plutonic belt in south and southern parts of the Bardsir

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plain. The hydrothermal warm springs mainly discharge into the Lalezar River, one of the main

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tributaries of the Ab-Bakhsha River. Today, the hydrothermal warm springs are used by native

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people due to both the folklore and the claimed medical values. In this study, cold surface waters

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and hydrothermal warm springs were sampled from the upper tributaries of the Ab-Bakhsha

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River for hydro-geochemical analysis (Fig. 4).

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Collected samples for trace elements determination were immediately filtered through

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0.45 µm filters (ALBET, Nitrato Celulosa, model), acidified with concentrated HNO3 (at pH <2),

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and were stored at 4 ºC in polyethylene bottles until elemental analysis was performed. Filtered 6

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(through 0.45 µm filters) un-acidified samples were also collected for anion analysis. Parameters

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such as pH, Eh, temperature (T) and electrical conductivity (EC) of the water were measured in

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the field by the use of calibrated multi-parameter devices (Toledo MP-120 model for pH, T and

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EC and SenTix ORP model for Eh). The pH-meter was calibrated using buffer solutions (pH = 4

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and 7) and the redox electrode was checked with the redox buffer solution (WTW RH 28). Major

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and trace element concentrations in water samples were determined using ICP-OES and ICP-

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MS, respectively, at the Labwest Laboratory, Perth, Australia. Sulfate, bicarbonate and chlorine

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were determined by spectrophotometric, titration, and Mohr's methods (Skoog et al., 1996),

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respectively. Analytical and instrumental quality assurance and quality control (QA/QC) was

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evaluated using sample duplicates and certified reference standards that indicate a precision of

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better than ±10% for the obtained results.

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3.3. X-ray diffraction method (XRD)

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Travertine rocks and their associated reddish-brown layers were analyzed separately

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using X-ray diffraction (XRD) method. The mineralogy of collected samples was qualitatively

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determined by a Philips Xpert pro X-ray diffraction system at the Iran Mineral Processing

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Research Centre (IMPRC), Karaj, Iran. This XRD system uses cobalt radiation (Kα line with a

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mean wavelength of 1.789 Å), operated at 40 kV and 35 mA. The scans were recorded from 4 to

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85 2θ.

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4. Arsenic geochemistry in the travertine deposits

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Table 1 shows the content of arsenic and some of the other target elements in the

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travertine samples and their associated reddish-brown deposits. Arsenic content ranges from 9 to

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90,400 mg/kg in the collected samples. Of significant interest, this potentially toxic element is

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highly concentrated in the samples collected from reddish-brown layers.

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In this study, normalized enrichment factor (NEF, Khorasanipour and Eslami, 2014) was

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used to evaluate geochemical enrichment of the target elements. This enrichment factor was

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calculated on the basis of the crustal abundance (Rudnick and Gao, 2003) and normal content of

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each target element in the carbonate rocks (Mason and Moore, 1982) (Eq. 1). 7

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NEF =

[M ] [ Sc] [M ] [ Sc]

Investigated samples

Crustal abundance or carbonate rocks

Eq.1

where, NEF is the normalized enrichment factor, [M] is the total content of target elements and

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[Sc] is the content of Sc that was used as the normalizing element (Shotyk et al., 2000). The

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results of the normalized enrichment factor are presented in supplementary figures S-1a and b.

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According to this calculation, As and Tl have a considerable enrichment in the collected samples

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comparing to their values in the earth's crust and carbonate rocks. Based on the crustal

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abundances, the maximum median enrichment values were calculated for As, Tl, Sb, Cd, S, Cu,

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Se, Mn, Mo, and Zn, respectively. Most of these elements, especially As, Tl, Cu, Sb, Cd, Zn,

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Mo, and Se, also have higher enrichment than their contents in the carbonate rocks. An exception

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was found for Mn, and S, which have higher content in the carbonate rocks comparing to their

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crustal abundances. This elemental association is mainly due to the high content of these

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elements in the reddish-brown deposits.

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5. XRD mineralogical results

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The X-ray mineralogical results of the selected samples from travertine rocks and their

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associated reddish-brown deposits are shown in the supplementary table S1. The main mineral

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assemblage of the travertine samples is quartz-calcite-aragonite±hematite. The presence of

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hematite in this mineral assemblage is due to the thin layers of reddish-brown deposits in the

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travertine samples. The mineral assemblage of the reddish-brown deposits was different from

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travertine samples, except for quartz and calcite, which were found in nearly all samples. Other

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identified phases in the reddish-brown samples were pyrolusite, albite, alkali feldspar, hematite,

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mica and amorphous materials. The presence of Fe and Mn oxy-hydroxides in the reddish-brown

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deposits show their great potential for adsorption processes, a mechanism that is very important

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from an environmental point of view. Yukonite [Ca7Fe3+12 (AsO4)10(OH)2015H2O], a rare Ca

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ferric arsenate hydrous mineral, is the only arsenic bearing mineral that was identified in the two

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samples of the reddish-brown deposits. Since the first finding of Yukonite in the Yukon

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Territory, Canada (Tyrrell and Graham, 1913), this mineral has been reported only at a few

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locations in the world such as in North America and Europe (Dunn, 1982; Ross and Post, 1997;

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Pieczka et al., 1998), and also in the numerous As-rich calcareous deposits of the active

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geothermal areas of the Kamchatka Peninsula, Russia (Nishikawa et al., 2006). The structure of

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Yukonite is more often as fractured, gel-like aggregates of dark brownish or the reddish-brown

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color (e.g. Swash, 1996; Pieczka et al., 1998; Nishikawa et al., 2006).

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6. Hydro-geochemical results

General hydro-geochemical analysis and the concentration of arsenic in the collected

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water samples are shown in tables 2. As noted earlier, water samples were collected from the

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geothermal warm springs, cold mineral springs, river waters, and natural springs. Field and

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laboratory results showed that the hydro-geochemical characteristics of the water samples are

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different, remarkably. The temperature of geothermal springs ranged from 25.2 to 38.0 ºC, which

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is corresponded with the low temperature warm waters. The pH values ranged between 6.2 and

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8.6, indicating a slightly acidic to basic characteristic of the collected samples. Non-geothermal

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waters (W-10 to W-12) were slightly bicarbonate with pH values near neutral and also have low

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total dissolved solids (TDS<500 mg/Kg), while the geothermal warm waters tend to have more

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sodium and chloride concentration, with dissolved salt contents higher than 8,300 mg/L. Field

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measured redox potential (Eh) ranged between 41-230 mV and the electric conductivity (EC)

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ranged from 342-12,800 µS/cm. The mean electrical conductivity of the geothermal warm waters

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was 11,400 µs/cm, which is remarkably higher than the other collected samples.

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According to the relative concentrations of major cations and anion ions using

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conventional piper diagrams (Freeze and Cherry, 1979), the water samples can be classified into

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three main types: Na-Cl, Na-HCO3 and Ca-HCO3 (Fig. 5). As is shown in table 2 and figure 5,

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Cl- and Na+ are the dominant ions in the geothermal related warm waters. Previous studies also

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showed that the geothermal waters are of Na-Cl type (Yokoyama et al., 1993; Bundschuh and

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Maity, 2015). The geothermal related warm waters are characterized by a major ion chemistry of

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1,362 mg/L HCO3-, 2,547 mg/L Na+, 2,371 mg/L Cl–, 194 mg/L Ca2+, 48.8 mg/L Mg2+, and

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1,380 mg/L SO42, the mean values are presented. The type of the water samples collected from

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cold mineral springs associated with the travertine deposits is Na-HCO3. By increasing the

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distance from discharge point of the geothermal springs, downstream along the Lalezar tributary

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of the Ab-Bkhsaha River, the type of the surface waters is also changed from Na-Cl to the Na-

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HCO3. This hydro-geochemical change is as a result of mixing of waters with different hydro-

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geochemical characteristics. The water type of the non-thermal surface waters, including un-

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contaminated tributary of the Ab-Bakhsha River (W10) and natural springs (W11 and W12), was

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Ca-HCO3. According to Gibbs (1970), this water type is as a result of the weathering dominated

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process. It is also noticeable that, the concentrations of SO4-2, Na+, and Cl- in the hydrothermal

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warm springs are higher than the drinking water threshold limits (WHO, 2006; U.S.EPA, 2009).

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Extremely high concentration of As (>24,000 µg/L) was found in the hydrothermal warm waters, the mean value is presented (Table 2). The concentration of As in the Lalezar warm

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springs reached to more than 30,000 µg/L. Cold mineral springs associated with the travertine

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deposits (W6 and W7) and geothermal affected waters of the Ab-Bakhsha River (W8 and W9)

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also have As concentrations higher than the WHO (2006) and U.S EPA (2009) drinking water

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recommended values, but remarkably lower than the geothermal affected warm springs. By

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contrast, the concentration of As was very low and even lower than the drinking water

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recommended values (<10µg/L, WHO, 2006; U.S.EPA, 2009) in the natural springs and non-

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geothermal surface waters. Although, the As concentrations in these water sources are low, but

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mixing with the hydrothermally contaminated waters can increase the As content in the

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downstream waters along the Ab-Bakhsha River. Arsenic concentrations in river waters from

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geothermal areas have been reported typically at around 10–70 µg/L (Smedley and Kinniburgh,

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2002), although higher values also have been reported. For example, arsenic concentrations up to

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370 µg/L in Madison River water (Wyoming and Montana) have been reported by Nimick et al.

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(1998) as a result of geothermal inputs from the Yellowstone geothermal system.

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The relationships between As with pH, Eh, EC, Cl, SO4, Na and K are shown in figures

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6A-G, respectively. Arsenic is negatively related with the pH and Eh values, suggesting that

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more arsenic concentration occurs in the slightly acidic and more reduced warm waters of the

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geothermal source (W1 to W5). By contrast to the Eh and pH, arsenic shows positive correlation

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with EC, Cl, SO4, Na and K. These correlation are significant at the 0.01 level (2-tailed).

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According to Wright (1991), the amount and nature of dissolved chemical species in the

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geothermal fluids are functions of temperature and of the local geology. For example, Na and K

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can release into the hydrothermal waters through the leaching of host rock minerals such as

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albite and orthoclase, respectively. Redox potential (Eh) and pH are the most important factors that control the predominant

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form or speciation of the arsenic in the water environment. Under oxidizing conditions, H2AsO4–

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is dominant at low pH (less than about pH 6.9), whilst at higher pH, HAsO42– becomes dominant

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(H3AsO40 and AsO43– may be present in extremely acidic and alkaline conditions, respectively).

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Under reducing conditions at pH<9.2, the uncharged arsenite species H3AsO30 will predominate

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(Brookins, 1988; Wilkie and Hering, 1998; Bauer and Blodau, 2006). According to the measured

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Eh and pH values, the dominant specie of As in the geothermal warm waters is H3AsO30, while

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the As specie in the other samples is mainly as HAsO42– (Fig. 7).

As well as arsenic, a remarkable difference was observed between the concentrations of B,

12

Cs, Fe, Li, Mn, Mo, Rb, Sb, Se, Si, and Tl in the geothermal warm waters with the other samples

13

(supplementary Table S2). The maximum and minimum concentrations of these elements were

14

observed in the geothermal warm springs and the natural springs or non-geothermal waters,

15

respectively. The concentrations of B in the contaminated samples (W1-W9) ranged from 838 to

16

51,000 µg/L. Lithium concentrations were also high, ranged between 87.3 and 3,650 µg/L. Other

17

elements enriched in the geothermal warm springs are: Cs (252-670 µg/L), Mn (154-451 µg/L),

18

Fe (160-1,930 µg/L), Mo (16.1-36.5 µg/L), Rb (348-722 µg/L), Sb (3.9-138 µg/L), Se (14.2-22.3

19

µg/L), and Tl (2.88-6.96 µg/L). Concentrations of the elements such as B, Fe, and Sb are higher

20

than the WHO (2006) and U.S.EPA (2009) recommended values for drinking water. Most of the

21

above mentioned hydro-chemical relationships have been reported in the literature as the general

22

characteristics of the hydrothermal waters in the world (Stauffer and Thompson, 1984; Smedley

23

and Kinniburgh, 2002; Millot et al., 2012; Barats et al., 2014; Bundschuh and Maity, 2105).

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7. Discussion and application of results for the regional analysis The results obtained from this study strongly verify the positive role of the geothermal

27

activities in the As contamination in the Kerman Cenozoic Magmatic Arc. Travertine rocks, as

28

the old indicators of the geothermal related processes in the quaternary, are accompanied with

29

the reddish-brown deposits that have very high concentration of As (> 52,000 mg/Kg). Similar

30

red As-rich precipitations have been reported from various locations in the world, such as 11

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Champagne Pool in the Waiotapu geothermal field (amorphous deposit containing up to 2wt%

2

As) (Weissberg, 1969), and Steamboat Springs in Colorado (White, 1968). Baba and Sözbilir

3

(2012) proposed that arsenic enrichment in the limestone/dolomite (3–699 ppm) or travertine

4

deposits (5–4,740 ppm) is as a result of secondary enrichment through hydrological systems.

5

Therefore, arsenic is an important trace component in hydrothermal systems, and is able to

6

accumulate in the related deposits, e.g. in iron sulfides, oxides, and hydroxides. According to the

7

Crouzet et al. (2003), active precipitation of Fe oxy-hydroxides and carbonates is as a result of

8

the oxygenation and CO2 degassing from previous hydrothermal waters. The strong association

9

between As and Fe, as observed in the collected samples from hydrothermal deposits, is in good

10

agreement with literature data on As, that emphasis on the importance of Fe oxy-hydroxides in

11

the cycling and regulation of As in the surface environments (e.g. Pierce and Moore, 1982; Fuller

12

et al., 1993; Price and Pichler, 2005; Crouzet et al., 2003). Bioavailability of arsenic is limited by

13

the adsorption processes in the surface oxidizing environments. For example, iron as amorphous

14

oxy-hydroxide compounds provides an important sink for arsenic immobilization in such

15

conditions. Arsenate (As+5) adsorption by hydrous iron oxides is particularly strong (Goldberg,

16

1986; Manning and Goldberg, 1996). It is notable that, arsenic contents in primary rock-forming

17

minerals such as aluminosilicate minerals are generally low (1 mg/Kg or less) and this element

18

can only substitutes as As3+ for Fe3+ or Al3+ (Smedley and Kinniburgh, 2002).

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At many geothermal fields, it has been noted that As is mainly concentrated in pyrite at

20

depth. Arsenic minerals such as arsenopyrite (FeAsS) appear to be uncommon in the rocks of

21

geothermal reservoirs themselves, but a range of As minerals are precipitated from geothermal

22

surface features such as hot springs (Webster and Nordstrom, 2003). Comparing to the other

23

ferric arsenate minerals such as scorodite (FeAsO4 2H2O), which is more stable at the acidic pH

24

values, the Ca-Fe arsenates (such as yukonite) are thought to be stable at higher pH values

25

(Harvey et al., 2006; Bluteau et al., 2009; Meunier et al., 2010). The different stabilities of these

26

As-bearing minerals can profoundly affect the As bio-accessibility. For example, it has been

27

shown that As in youkonite has higher bio-accessibility than As in the scorodite (Jamieson et al.,

28

2006; Meunier et al., 2010).

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High concentrations of As have been reported in most active geothermal fields of the world (e.g. Horton et al., 2001; Smedley and Kinniburgh, 2002; Bundschuh and Maity, 2105). 12

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Common concentrations are in the range of thousands to tens of thousands of µg/L (Bundschuh

2

and Maity, 2105). The wide range of concentrations (less than 0.1 to nearly 50 mg/L), strongly

3

depends on the geology and hydro-geochemical characteristics of the area (Ballantyne and

4

Moore, 1988; Bundschuh and Maity, 2105). Most of the hydro-geochemical characteristics

5

observed in the investigated samples are typical indicators for the hydrothermal affected waters

6

with high arsenic concentration. The hydro-geochemical characteristics of the hydrothermal

7

waters will be changed during their rising from the deep geothermal reservoir to or near to the

8

earth's surface due to the physical, chemical and biological processes (Bundschuh and Maity,

9

2105). Undoubtedly, these hydro-chemical changes will continue during the movements of the

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contaminated waters in the surface environment. Several factors, including: (1) the mixing effect

11

of the non-geothermal surface and subsurface waters; (2) changes of the redox potential from

12

nearly reducing conditions to the oxidizing conditions, and (3) adsorption, co-precipitation or

13

even ion exchange reactions are responsible for the physical, chemical and biological changes of

14

the hydrothermal waters in the surface environments. Collectively, these processes are

15

considered as the “natural attenuation mechanisms” (Webster et al., 1994; Guo et al., 2015).

16

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The geothermal springs with Na—Cl water type generally have the highest As concentrations (Bundschuh and Maity, 2105). The correlation between As and Cl does not prove a common

18

source for these elements lonely, because As is derived predominantly from the leaching of the

19

reservoir host rocks, while chloride ions may be originated from (1) reservoir host rock leaching;

20

(2) seawater component; and (3) gaseous HCl from magmatic components (Ballantyne and

21

Moore,1988; Bundschuh and Maity, 2105).

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Each of the constituents of the geothermal warm waters behaves in its own peculiar way, and

23

will provide unique information. Some of the classifications of hydrothermal waters are based on

24

the ternary diagrams of Cl-SO4-HCO3, Li-Cl-B, and Li-Rb-Cs (Giggenbach, 1991; Mnjokava,

25

2007). In the hydro-geochemical analysis, elements such as Cl, B, Li, Rb, and Cs, are considered

26

as ‘conservative’ constituents (Giggenbach, 1991; Sedwick and Stuben, 1996; Mnjokava, 2007;

27

Barats et al., 2014). For example, Chloride, which is a conservative ion in geothermal fluids,

28

does not take part in reactions with rocks after it has dissolved. That is to say, chloride does not

29

precipitate after it has dissolved; it does not return to the rock so its concentration is independent

30

of the mineral equilibria that control the concentration of the rock-forming constituents. Thus,

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conservative elements can be used as a tracer in geothermal investigations. Also, in the

2

geothermal waters, the components such as the rare alkalis Li, Rb and Cs, if added at depth, are

3

not affected by shallow processes (Mnjokava, 2007). For example, Li has been used as a tracer,

4

because it is the alkali metal least affected by secondary processes. Once added, Li remains

5

largely in solution. Lithium is used as a reference for evaluating the possible origin of two other

6

important ‘conservative’ constituents of geothermal waters, Cl and B (Mnjokava, 2007). It seems

7

that, semiarid climate conditions of the investigated area has a considerable potential to influence

8

the concentration of the conservative ions in the surface and groundwater through the high

9

evaporation rate in the summer and flushing events in autumn and winter seasons.

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Low temperatures of the investigated geothermal springs (<38 ºC) may be related to the

11

(1) losing a part of their heat by conductive cooling (the transfer of heat from hydrothermally

12

heated water to the cooler surrounding rocks by direct contact) during upward migration of the

13

original geothermal waters; and (2) mixing with the cold non-geothermal waters. The pH of

14

geothermal water increases due to CO2 loss during adiabatic cooling (the process of reducing

15

heat through a change in pressure caused by volume expansion) of uprising thermal water and

16

base metal precipitation (Bundschuh and Maity, 2105). It is notable that, elements like As and Sb

17

can remain soluble event in high pH conditions. These elements will precipitate later in the zone

18

closer to the earth's surface (Bundschuh and Maity, 2105).

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In the previous studies, same targets were done in the hydrothermal fluids also showed

20

that H3AsO30 is the predominant species at the geothermal source (Yokoyama et al., 1993). As

21

the hydrothermal fluid ascends through the outlet conduits, the reduced species of arsenic

22

(H3AsO30) oxidize in situ to As (V) in the form of HAsO42– or H3AsO4 (Pichler et al., 1999;

23

Schwenzer et al., 2001; Webster and Nordstrom, 2003; Alsina et al., 2013). Therefore, the

24

uprising geothermal waters are normally reducing (suggesting the presence of predominantly As

25

(ΙΙΙ) species) at depth, but it is expected that in contact with the shallow aquifers or mixes with

26

surface waters, the redox conditions become oxidized, a condition that will change As speciation.

27

In such oxidizing systems, the mobility of As is a function of the redox transformation of the As

28

(ΙΙΙ) to the oxidized As (V) species. The As(V) species is then sorbed on oxide minerals, i.e.,

29

amorphous Al, Mn and Fe oxides and hydroxides, a process that is responsible for high values of

30

As in the reddish-green deposits associated with the travertine rocks in the Kerman Cenozoic

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Magmatic Arc. Therefore, the travertine deposits must be considered as the major sink for As.

2

The mobility of arsenic from geothermal source is limited in the surface oxidizing environments.

3

This mechanism together with the dilution effect of non-geothermal surface and subsurface

4

waters are responsible for the remarkable decrease of arsenic concentration in downstream of the

5

geothermal warm springs. In spite of these facts, the arsenic concentration rarely decreases to

6

lower than the permissible drinking water recommended value (10 µg/L), because pH is also

7

important in controlling arsenic behavior in the natural water in environment. In contrast to the

8

other potentially toxic trace elements, such as Pb, Cu, Ni, Cd, Co and Zn, which occur in

9

solution as cations and become increasingly insoluble as the pH increases, oxyanion-forming

10

elements such as Cr, As, U and Se tend to become less strongly sorbed as the pH increases

11

(Dzombak and Morel, 1990). However, compared with the other oxyanion-forming elements,

12

arsenic is one of the most problematic in the environment because of its relative mobility over a

13

wide range of redox conditions.

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By reviewing the previous works (Khajehpour, 2007; Ebrahimi, 2009; Mirzaie, 2012;

15

Abbasnejad et al., 2103; Pazand and Javanshir, 2103), several important issues were revealed

16

about the arsenic contaminations in the Kerman Cenozoic Magmatic Arc. These findings also

17

somewhat confirm the outstanding role of the geothermal activities in the arsenic contamination.

18

The main points are as follows:

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1- Arsenic contamination in the groundwater of the Bardsir and Rafsanjan plains occurs in

20

the slightly acidic to near alkaline pH values (Khajehpour, 2007; Mirzaie, 2012). Arsenic

21

concentration ranges from 7.24 to 174.5 µg/L and 1.3 to 464.5 µg/L in the Rafsanjan and

22

Bardsir plains, respectively. The increases of As concentration due to the desorption

23

reactions at high alkaline pH values is proposed by Abbasnejad et al (2013) for the

25 26 27

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possible source of this element in groundwaters of the Bardsir plain. Figures 8 A and B show the arsenic concentrations versus pH for the groundwater of the Bardsir and Rafsanjan plains, respectively. According to these figures, it is hard to establish a general trend between As concentrations and pH. But it can say that, if arsenic present in this

28

range of pH it can remain as soluble form higher than recommended values (>10 µg/L).

29

Therefore, the desorption mechanism cannot explain the source of As in all groundwater

30

samples of the Bardsir and Rafsanjan plains. It is also noticeable that, the aquifer of the 15

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Bardsir and Rafsanjan plains are recharged mainly from the mountainous area of the

2

Kerman volcano-plutonic belt (Fig. 1), where we found high natural anomalies of As in

3

the travertine deposits and geothermal related warm waters. Also, the concentrations of

4

the some conservative elements such as B (mean value 1,720 µg/L and ranges from 268

5

to 7,100 µg/L) and Li (mean value 210 µg/L and ranges from 39.1 to 901.8 µg/L) are

6

relatively high in the groundwater of the Brdsir plain (Mirzaie, 2012).

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2- Decomposition of sulfides presenting in the mountainous volcanic rocks (Abbasnejad et

8

al., 2103) and the Cu-porphyry mining activities are the other controversial issues related

9

to the possible sources of arsenic contamination in the Kerman volcano-plutonic belt.

10

Table 3 shows the statistical summarize of As concentrations and pH values for different

11

water resources associated with the Sarcheshmeh industrial complex. These water

12

samples are from acidic rock wastes drainages, mining related waters, industrial

13

contaminated effluents (Khorasanipour et al., 2011), and water resources that are

14

associated with the Sarcheshmeh mine tailings (Khorasanipour and Esalmi, 2014). The

15

pH of these water samples rages from 2.5 to 12.2. This unusual range of pH is a result of

16

different geo-genic and anthropogenic processes affecting the hydro-chemical

17

characteristics of the water. As is shown in table 3, the maximum concentrations of

18

arsenic occurs in the industrial contaminated effluents, while As concentrations under

19

strong acidic conditions, such as rock waste drainages, highly weathered tailings, and

20

mining related waters are mainly below recommended drinking water threshold limits

21

(U.S. EPA, 2009; WHO, 2006) or even below detection limit (<5 µg/L). The maximum

22

concentration of As in the industrial waste waters of the Sarcheshmeh industrial complex

23

is 442 µg/L at pH 7.58 (Khorasanipour et al., 2011). The maximum concentration of As

25 26 27

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in the safety bay and monitoring wells of the Sarcheshmeh tailings dam are 113 and 125 µg/L, respectively. It seems that, these anomalies of As is also associated with the industrial sources of the Sarcheshmeh copper complex. Previous studies(Khorasanipour and Eslami, 2014; Khorasanipour et al., 2011) showed that the geochemical behavior of

28

As and Mo is different from that of the elements such as Cd, Co, Cu, Zn, Ni, Al and S in

29

the water samples associated with the mining and industrial related contamination

30

sources of the Sarcheshmeh mine. According to the Khorasanipour et al. (2011, 2012), 16

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As is principally adsorbed or co-precipitated with the amorphous and crystalline Fe

2

oxides, a geochemical mechanism that is also responsible for the As retention in soil

3

developed on the gossans or mineralized zones around the Sarcheshmeh copper mine

4

(Khorasanipour and Aftabi, 2011). This unique geochemical behavior of arsenic has also

5

been shown by other authors (Marszalek and Wasik, 2000; Williams, 2001). Generally,

6

as shown by the other studies in the world (Smedley and Kinniburgh, 2002), the role of

7

mining and industrial related activities in the surface and groundwater As contamination

8

in the Kerman Cenozoic Magmatic Arc is local.

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3- Nearly 25.62 % of groundwater samples investigated by Pazand and Javanshir (2013)

10

have arsenic concentrations above WHO (2006) permissible value (10 µg/l) for drinking

11

waters in the Rayen area. High As concentrations in this area (25,000, 23,100, 9,440 and

12

1,480 µg/L) are associated with the western part with volcanic geology. As same as our

13

results, in the Rayen plain, the dominant As species are H3AsO3 (As-III) and HAsO42-

14

and water samples are mostly Na–Cl type. These hydro-geochemical characteristics are

15

compatible with the geothermal source of As. Although, on the basis of the positive

16

correlation between arsenic and bicarbonate, and negative correlation between arsenic

17

with iron, nitrate, and sulphate, Pazand and Javanshir (2013) concluded that arsenic is

18

released

19

oxides/oxyhydroxides and also Fe may be precipitated as iron sulfide when anoxic

20

conditions prevail in the aquifer sediments. These mechanisms are also faced with several

21

challenging issues. For example, the organic C content of the buried sediment, as an

22

effective factor, will largely determine the rate at which reducing conditions are created

23

(Smedley and Kinniburgh, 2002; Raju et al., 2012; Smedley and Kinniburgh, 2005). This

25 26

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groundwater

through

reduction

of

arsenic-bearing

iron

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theory, which consider reducing conditions as a result of organic matter decomposition, cannot explain the arsenic increases in the aquifers such as Rayen, Bardsir, and Rafsanjan, which are very poor in organic matter.

27

In the Kerman Cenozoic magmatic arc, it seems that, most of hydrothermal waters cannot reach

28

to the surface as hot or warm springs due to the: (1) arid and semi-arid climatological conditions;

29

(2) lowering the water table due to the long-lasting drought periods; and also (3) excessive

30

withdrawal of the groundwater for drinking and agricultural uses. For example, on average, 17

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1

every year about 200 million cubic meters of groundwaters are extracted (mainly via drill wells)

2

in the Bardsir plain to be used for agricultural and domestic purposes (Abbasnejad et al., 2013).

3

Therefore, it is possible that contaminated geothermal waters can reach into the aquifers through

4

the subsurface recharge.

6

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8. Conclusion

This study provides special insight into the geo-genic arsenic contamination in the

8

Kerman Cenozoic magmatic arc. The intense hydrothermal activity that occurred in the past,

9

together with the active hydrothermal warm springs represent a potential source of arsenic to the

10

environment. Calcareous terraces, as the old indictors of the hydrothermal activities in the

11

quaternary, are accompanied with the arsenic enriched reddish-brown deposits. These deposits,

12

which are as one of the most important sinks for hydrothermal arsenic, was reached to more than

13

52,000 mg/Kg of As. Adsorption mechanisms, which limits the mobility and bio-availability of

14

As, are very important from an environmental point of view. The association of As with Co, Cu,

15

Mo, Sb, Tl, Se, Fe, and Mn in the travertine deposits must be considered as one of the

16

geochemical signature of the previous hydrothermal activities in this area.

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Undoubtedly, geothermal activity plays a major role in the arsenic contamination of

18

surface and subsurface water in the Kerman Cenozoic Magmatic Arc. The Na-Cl type of

19

hydrothermal warm waters with extremely high As concentration (>24,000 µg/L) in the form of

20

H3AsO30 and hydro-chemical association of As with EC, Cl, SO4, Li, B, Se, Mo, Tl, Sb, Li, Cs,

21

Rb, Si, Fe, Mn, and Zn are the outstanding hydro-geochemical features of the investigated

22

waters. Natural attenuation profoundly reduce the contamination potential of the hydrothermal

23

contaminated waters, but the arsenic concentration in the downstream surface and subsurface

24

waters still remains higher than the recommended value for safe drinking water. Despite the

25

construction and operation of drinking water treatment facilities in some urban areas such as the

26

Bardsir Township, rural communities and some of the other townships of the Kerman province

27

are still depending on arsenic enriched waters for their drinking and irrigation needs. Thus,

28

arsenic-contaminated water is still as one of the critical environmental challenges in the Kerman

29

province.

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Acknowledgments

2

The authors appreciate Prof. A. Aftabi for his constructive and valuable suggestions. The

3

comprehensive reviews of an earlier version of the manuscript by the editor and two anonymous

4

reviewers from the Journal of Applied Geochemistry are greatly appreciated.

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References

7

Abbasnejad, A., Mirzaie, A., Derakhshani, R., Esmaeilzadeh, E., 2013. Arsenic in groundwaters

9

of the alluvial aquifer of Bardsir plain, SE Iran. Environ. Earth. Sci 69, 2549–2557. Ahn, J.S., Cho, Y.C., 2013. Predicting natural arsenic contamination of bedrock groundwater for

14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

M AN U

13

speciation in sinter mineralization from a hydrothermal channel of El Tatio geothermal field, Chile. J. Hydrol. 518, 434–446. Asadi, S., Moore, F., Zarasvandi, A., 2014. Discriminating productive and barren porphyry copper deposits in the southeastern part of the central Iranian volcano-plutonic belt, Kerman region, Iran: A review. Earth Sci. Rev. 138, 25-46. Baba, A., Sözbilir, H., 2012. Source of arsenic based on geological and hydrogeochemical

TE D

12

a local region in Korea and its application. Environ. Earth. Sci. 68, 2123–2132. Alsina, M.A., Zanella, L., Hoel, C., Pizarro, G.E., Gaillard, J.F., Pasten, P.A., 2013. Arsenic

properties of geothermal systems in Western Turkey. Chem. Geol. 334, 364–377. Ballantyne, J.M., Moore, J.N., 1988. Arsenic geochemistry in geothermal systems. Geochim. Cosmochim. Acta 52, 475–83. Barats, A., Féraud, G., Potot, C., Philippini, V., Travi, Y., Durrieuc, G., Dubar, M., Simler, R.,

EP

11

2014. Naturally dissolved arsenic concentrations in the Alpine/Mediterranean Var River watershed (France). Sci. Total. Environ. 473, 474, 422–436.

AC C

10

SC

8

Bauer, M., Blodau, C., 2006. Mobilization of arsenic by dissolved organic matter from iron oxides, soils and sediments. Sci. Total. Environ. 354, 179–190. Berg, M., Tran, H.C., Nguyen, T.C., Pham, H.V., Schertenleib, R., Giger, W., 2001. Arsenic contamination of groundwater and drinking water in Vietnam: a human health threat. Environ. Sci. Technol. 35, 2621–2626. Bluteau, M., Becze, L., Demopoulos, G.P., 2009. The dissolution of scorodite in gypsum saturated waters: Evidence of Ca-Fe-AsO4 mineral formation and its impact on arsenic retention. Hydrometallurgy 97, 221-227. 19

ACCEPTED MANUSCRIPT

7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

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6

of freshwater resources. J. Hazar. Mater. 262, 951–959. Bundschuh, J., Maity, J.P., 2015. Geothermal arsenic: Occurrence, mobility and environmental implications. Renew. Sustainable Energy Rev. 42, 1214–1222. Crouzet, C., Baranger, P., Conil, P., Guern, A.C.L., Bodénan, F., 2003. Arsenic trapping by iron oxy-hydroxides and carbonates at hydrothermal spring outlets. Appl. Geochem. 18, 1313– 1323.

SC

5

Cumbal, L., Vallejo, P., Rodriguez, B., Lopez, D., 2010. Arsenic in geothermal sources at the north-central Andean region of Ecuador: concentrations and mechanisms of mobility. Environ. Earth. Sci. 61, 299–310. Dimitrijevic, M.D., 1973. Geology of Kerman Region: Institute for Geological and Mining

M AN U

4

H.J., Tseng, Y.J., Bhattachary, P., Chen, C.Y., 2013. Naturally occurring arsenic in terrestrial geothermal systems of western Anatolia, Turkey: Potential role in contamination

Exploration and Investigation of Nuclear and Other Mineral Raw Material, Beograd– Yugoslavia. Iran Geol. Survey Rep. Yu/52. Dunn, P., 1982. New data for pitticite and a second occurrence of yukonite at Sterling Hill, New Jersey. Mineral. Mag. 46, 261-264. Dzombak, D.A., Morel, F.M.M., 1990. Surface Complexation Modeling Hydrous Ferric Oxides. Wiley, New York.

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3

Ebrahimi, M., 2009. Evaluation of Arsenic dispersivity and the survey of the source of Arsenic in Groundwaters of Rafsanjan plain and represent the suitable ways of removal arsenic. M.Sc. Thesis (in Persian), Shahid Bahonar University of Kerman, [203 pp.]. Ferguson, J.F., Gavis, J., 1972. A review of the arsenic cycle in natural waters. Water Res. 6

EP

2

Brookins, D.G., 1988. Eh-pH diagrams for geochemistry. Springer Berlin. Bundschuh, J., Maity, J.P., Nath, B., Baba, A., Gunduz, O., Kulp, T.R., Jean, J.S., Kar, S., Yang,

(11), 1259–1274. Freeze, R.A., Cherry, J.A., 1979. Ground Water. Prentice-Hall, New Jersey. Fuller, C.C., Davis, J.A., Waychunas, G.A., 1993. Surface chemistry of ferrihydrite: part 2. Kinetics of arsenate adsorption and coprecipitation. Geochim. Cosmochim. Acta 57, 2271–

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1

2282. Gibbs, R.J., 1970. Mechanism controlling world water chemistry. Science 170, 1088–1090. Giggenbach, W.F., 1991. Chemical techniques in geothermal exploration. In: D’Amore F, (coordinator), Application of geochemistry in geothermal reservoir development. UNITAR/UNDP publication Rome 119-142.

20

ACCEPTED MANUSCRIPT

7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

RI PT

6

Geochem. doi:10.1016/j.apgeochem.2015.01.017. Gurzau, E.S., Gurzau, A.E., 2001. Arsenic exposure from drinking groundwater in Transylvania, Romania: an overview. In Arsenic Exposure and Health Effects IV (eds. Chappell WR, Abernathy CO, and Calderon RL.). Elsevier, Amsterdam, 181–184. Harvey, M.C., Schreiber, M.E., Rimstidt, J.D., Griffith, M.M., 2006. Scorodite dissolution kinetics: Implications for arsenic release. Environ. Sci. Technol. 40, 6709-6714.

SC

5

Heinrichs, G., Udluft, P., 1999. Natural arsenic in Triassic rocks: a source of drinking-water contamination in Bavaria, Germany. Hydrogeol. J. 7, 468–476. Hopenhayn-Rich, C., Biggs, M.L., Fuchs, A., Bergoglio, R., Tello, E.E., Nicolli, H., Smith, A.H., 1996. Bladder cancer mortality associated with arsenic in drinking water in

M AN U

4

Guo, Q., Cao, Y., Li, J., Zhang, X., Wang, Y., 2015. Natural attenuation of geothermal arsenic from Yangbajain power plant discharge in the Zangbo River, Tibet, China. Appl.

Argentina. Epidemiology 7, 117–124. Horton, T.W., Becker, J.A., Craw, D., Koons, P.O., Chamberlain, C.P., 2001. Hydrothermal arsenic enrichment in an active mountain belt: Southern Alps, New Zealand. Chem. Geol. 177, 323–339. Iskandar, I., Koike, K., Sendjaja, P., 2012. Identifying groundwater arsenic contamination mechanisms in relation to arsenic concentrations in water and host rocks. Environ. Earth.

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Sci. 65, 2015–2026. Jamieson, H.E., Corriveau, M.C., Parsons, M.B., Koch, I., Reimer, K.J., 2006. Mineralogy and bioaccessibility of arsenic-bearing secondary phases in gold mine tailings. Geochim. Cosmochim. Acta 70, A289-A289.

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Goldberg, S., 1986. Chemical modelling of arsenate adsorption on aluminium and iron oxide minerals. Soil. Sci. Soc. Am. J. 50, 1154–1160.

Khajehpour, S., 2007. Assessment of the concentration of heavy metals in groundwaters of Southern Rafsanjan Plain, focusing on the likely effects of Sarcheshmeh Copper Complex. M.Sc. Thesis (in Persian) Shahid Bahonar University of Kerman [154 pp.]. Khorasanipour, M., Aftabi, A., 2011. Environmental geochemistry of toxic heavy metals in soils

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around Sarcheshmeh porphyry copper mine smelter plant, Rafsanjan, Kerman, Iran. Environ. Earth. Sci. 62, 449–465. Khorasanipour, M., Eslami, A., 2014. Hydrogeochemistry and Contamination of Trace Elements in Cu-Porphyry Mine Tailings: A Case Study from the Sarcheshmeh Mine, SE Iran. Mine Water Environ. 33, 335-352.

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7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

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6

mineralogy and chemical fractionation of mine and processing wastes associated with porphyry copper mines: a case study from the Sarcheshmeh mine, SE Iran. Appl. Geochem. 26, 714–730. Kurttio, P., Pukkala, E., Kahelin, H., 1999. Arsenic concentrations in well water and risk of bladder and kidney cancer in Finland. Environ. Health. Perspect. 107, 705–710. Li, C., Kang, S., Chen, P., Zhang, Q., Mi, J., Gao, S., Sillanpaa, M., 2014. Geothermal spring

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5

causes arsenic contamination in river waters of the southern Tibetan Plateau, China. Environ. Earth. Sci. 71, 4143–4148. López, D.L., Bundschuh, J., Birkle, P., Armienta, M.A., Cumbal, L., Sracek, O., Cornejo, L., Ormachea, M., 2012. Arsenic in volcanic geothermal fluids of Latin America. Sci. Total.

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Sarcheshmeh Porphyry Copper Mine, SE Iran. Mine Water Environ. 31, 199–213. Khorasanipour, M., Tangestani, M.H., Naseh, R., Hajmohammadi, H., 2011. Hydrochemistry,

Environ. 429, 57–75. Lottermoser, B.G., 2003. Mine Waste: Characterization. Treatment and Environmental Impacts. Springer, Berlin, 303pp. Manning, B.A., Goldberg, S., 1996. Modelling arsenate competitive adsorption on kaolinite, montmorillonite and illite. Clays Clay Min. 44, 609–623. Marszalek, H., Wasik, M., 2000. Influence of arsenic-bearing gold deposits on water quality in

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Zloty Stok mining area, SW Poland. Environ. Geol. 39, 888–892. Mason, B., Moore, C.B., 1982. Principles of geochemistry, 4th edn. Wiley, New York. Masscheleyn, P.H., Delaune, R.D., Patrick, W.H., 1991. Effect of redox potential and pH on arsenic speciation and solubility in a contaminated soil. Environ. Sci. Technol. 25, 1414–

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Khorasanipour, M., Tangestani, M.H., Naseh, R., Hajmohammadi, H., 2012. Chemical Fractionation and Contamination Intensity of Trace Elements in Stream Sediments at the

1419. Meunier, L., Walker, S.R., Wragg, J., Parsons, M.B., Koch, I., Jamieson, H.E., Reimer, K.J., 2010. Effects of Soil Composition and Mineralogy on the Bioaccessibility of Arsenic from Tailings and Soil in Gold Mine Districts of Nova Scotia. Environ. Sci. Technol. 44, 2667-

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2674. Millot, R., Hegan, A., Négrel, P., 2012. Geothermal waters from the Taupo Volcanic Zone, New Zealand: Li, B and Sr isotopes characterization. Appl. Geochem. 27, 677–688. Mirzaie, A., 2012. Arsenic concentration in groundwater of Bardsir plain and its environmental implication. M.Sc. Thesis (in Persian), Shahid Bahonar University of Kerman, [170pp.].

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report No. Yu. 53 [247pp.]. Nimick, D.A., Moore, J.N., Dalby, C.E., Savka, M.W., 1998. The fate of geothermal arsenic in the Madison and Missouri Rivers, Montana and Wyoming. Water Resour. Res. 34, 3051– 3067. Nishikawa, O., Okrugin, V., Belkova, N., Saji, I., Shiraki, K., Tazaki, K., 2006. Crystal symmetry and chemical composition of yukonite: TEM study of specimens collected from

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Nalychevskie hot springs, Kamchatka, Russia and from Venus mine, Yukon Territory, Canada. Mineral. Mag. 70, 73-81. Özkul, C., Ciftci, E., Köprübası, N., Tokel, S., Savas, M., 2014. Geogenic arsenic anomalies in soils and stream waters of Neogene Emet basin (Ku¨tahya-Western Turkey). Environ.

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program, Orkustofnun, Grensásvegur 9, IS-108 Reykjavík, Iceland, Reports Number 14. Nedimovic, R., 1973. Exploration for ore deposits in Kerman region. Geological Survey of Iran,

Earth. Sci. 73 (10), 6117-6130. Pazand, K., Javanshir, A.R., 2013. Hydrogeochemistry and arsenic contamination of groundwater in the Rayen area, southeastern Iran. Environ. Earth. Sci. 70, 2633–2644. Pichler, T., Veizer, J., Hall, G.E.M., 1999. The chemical composition of shallow-water hydrothermal fluids in Tutum Bay, Ambitle Island, Papua New Guinea and their effect on ambient seawater. Mar. Chem. 64, 229–252.

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Pieczka, A., Golobiowska, B., Franus, W., 1998. Yukonite, a rare Ca-Fe arsenate, from Redziny (Sudetes, Poland). Eur. J. Mineral. 10(6), 1367-1370. Pierce, M.L., Moore, C.B., 1982. Adsorption of arsenite and arsenate on amorphous iron hydroxide. Water. Res. 16, 1247–1253.

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Mnjokava, T.T., 2007. Interpretation of exploration geochemical data for geothermal fluids from the geothermal field of the Rungwe volcanic area, SE Tanzania. Geothermal training

Wright, P.M., 1991. Geothermal Direct Use, Engineering and Design Guidebook. second Edition, Chapter 4. Geo-Heat Center Oregon Institute of Technology Klamath Falls, Oregon 97601. Price, R.E., Pichler, T., 2005. Distribution, speciation and bioavailability of arsenic in a shallow-

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water submarine hydrothermal system, Tutum Bay, Ambitle Island, PNG. Chemical Geology 224, 122–135. Raju, N.J., 2012. Arsenic exposure through groundwater in the middle Ganga plain in the Varanasi environs, India: a future threat. J. Geol. Soc. India. 17, 302–314.

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Rudnick, R.L., Gao, S., 2003. Treatise on geochemistry, vol 3. Elsevier Ltd, Oxford, [pp 1–64]. Schwenzer, S.P., Tommaseo, C.E., Kersten, M., Kirnbauer, T., 2001. Speciation and oxidation kinetics of arsenic in the thermal springs of Wiesbaden spa, Germany. Fresenius' J. Anal. Chem. 371, 927–933. Sedwick, P., Stüben, D., 1996. Chemistry of shallow submarine warm springs in an arc-volcanic setting: Vulcano Island, Aeolian Archipelago, Italy. Mar. Chem. 53, 146– 161.

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Sengupta, S., Sracek, O., Jean, S.J., Lu, H.Y., Wang, C.H., Palcsu, L., Liu, C.C., Jen, C.H., Bhattacharya, P., 2014. Spatial variation of groundwater arsenic distribution in the Chianan Plain, SW Taiwan: Role of local hydrogeological factors and geothermal sources. J. Hydrol. 518, 393–409.

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Zealand. Appl. Geochem. 17, 445–454. Ross, D.R., Post, J.E., 1997. New data on yukonite. Powder Diffraction 12, 113-116.

Shafiei, B., Haschke, M., Shahabpour, J., 2009. Recycling of orogenic arc crust triggers porphyry Cu mineralization in Kerman Cenozoic arc rocks, southeastern Iran. Miner. Deposita. 44, 265-283. Shotyk, W., Blaser, P., Grunig, A., Cheburkin, A.K., 2000. A new approach for quantifying cumulative, anthropogenic, atmospheric lead deposition using peat cores from bogs: Pb in eight Swiss peat bog profiles. Sci. Total. Environ. 249, 281–295.

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Skoog, D.A.; West, D.M., Holler, F.J., 1996. Fundamentals of Analytical Chemistry, 7th Edition, Thomson Learning, Inc, USA. Simsek, C., 2013. Assessment of naturally occurring arsenic contamination in the groundwater of Sarkisla Plain (Sivas/Turkey). Environ. Earth. Sci. 68, 691–702.

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Roddick-Lanzilotta, A.J., McQuillan, A.J., Craw, D., 2002. Infrared spectroscopic characterization of arsenate (V) ion adsorption from mine waters, Macreas mine, New

Smedley, P.L., Kinniburgh, D.G., 2002. A review of the source, behaviour and distribution of arsenic in natural waters. Appl. Geochem. 17(5), 517–568. Smedley, P.L., Kinniburgh, D.G., 2005. Arsenic in groundwater and the environment. In: Selinus O, Alloway, B., Smedley, P.L., Centeno, J.A., Finkelman, R.B., Fuge, R., Lindh, U. (eds)

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Essentials of medical geology: impacts of the natural environment on public health. Elsevier, Amsterdam 263–299. Stauffer, R., Thompson, J.M., 1984. Arsenic and antimony in geothermal water of Yellowstone National Park, Wyoming, USA. Geochim. Cosmochim. Acta 48, 2547-2561.

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water and the prevalence rate of skin lesions in Bangladesh. Environ. Health Perspect. 107, 727–729. Tyrrell, J.B., Graham, R.P.D., 1913. Yukonite, a new hydrous arsenate of iron and calcium, from the Tagishi Lake, Yukon Territory, Canada, with a note on the associated symplesite. Transactions of the Royal Society of Canada 7(4), 13-18. United State Environmental Protection Agency (U.S.EPA)., 2009. National primary and

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secondary regulations. Available at: http://www.epa.gov/safewater. Webster, J.G., Nordstrom, D.K., Smith, K.S., 1994. Transport and natural attenuation of Cu, Zn, As, and Fe in the acid mine drainage of Leviathan and Bryant creeks. ACS Symp 550, 244–260.

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59780-0 Cambridge England July. Tondel, M., Rahman, M., Magnuson, A., 1999. The relationship of arsenic levels in drinking

Webster, J.G., Nordstrom, D.K., 2003. Geothermal arsenic. In:Welch, A.H., Stollenwerk, K.G., editors. Arsenic in groundwater: geochemistry and occurrence. New York: Springer 101– 125. Weissberg, B.G., 1969. Gold-silver ore-grade precipitates from New Zealand thermal waters. Econ. Geol. 64, 95-108. White, D.E., 1968. Environments of generation of some base-metal ore deposits. Econ. Geol. 63,

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301–35. Wilkie, J.A., Hering, J.G., 1998. Rapid oxidation of geothermal arsenic(III) in steam waters of the eastern Sierra Nevada. Environ. Sci. Technol. 32, 657–62. Williams, M., 2001. Arsenic in mine waters: an international study. Environ. Geol. 40, 267–278.

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Swash, P.M., Monhemius, A.J., 1994. Hydrothermal precipitation from aqueous solutions containing iron (III), arsenate and sulfate, In Hydrometallurgy ’94, ISBN 978-0-412-

World Health Organization (WHO)., 2006. Guidelines for drinking water quality: 1st addendum to 3rd edit, vol 1, Geneva, Switzerland. Yokoyama, T., Takahashi, Y., Tarutani, T., 1993. Simultaneous Determination of Arsenic and Arsenious Acids in Geothermal Water. Chem. Geol. 103, 103–111.

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Table captions:

32

25

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Table 1: Total contents of the target elements (mg/Kg) in the travertine and their associated

2

reddish-brown deposits. The detection limits are shown in parentheses.

3 4

Table 2. General hydro-geochemical parameters and concentration of arsenic in the water samples.

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Table 3. Mean, standard deviation and range of As concentrations and pH values in different

7

waters samples in the Sarcheshmeh copper complex.

8

Figure captions

9

Fig. 1. The location and simplified geological map of the Kerman Cenozoic Magmatic Arc

10

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(Modified after Dimitrijevic, 1973; Shahabpour and Kramers, 1987; Asadi et al., 2014)

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Fig. 2. Geological map and location of the calcareous terraces zone around the Sarcheshmeh

13

porphyry copper mine. The sample numbers are according to table 1.

14 15

Fig. 3. Reddish-brown deposits in the travertine rocks.

16

Fig. 4. The locations of water samples and some of travertine deposits in the volcano-plutonic

18

mountainous area around the Bardsir plain. The sample numbers are according to tables 1 and 2.

19

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Fig. 5. Water samples plotted on a conventional piper diagram. The different types of water

21

samples can be distinguished based on major and minor ions.

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Fig. 6. Scatter diagrams A to G showing the linear correlation between As with pH, Eh, EC, Cl,

24

SO4, Na and K, respectively. The correlation are significant at the 0.01 level (2-tailed).

25 26 27

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Fig. 7. The location of different water samples on the Eh-pH diagram of As.

28

Fig. 8. Arsenic concentrations versus pH for (A) groundwater of the Bardsir plain (Mirzaie,

29

2012); (B) groundwater of the Rafsanjan plain (Khajehpour, 2007).

30 26

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Supplementary table captions

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Supplementary table S1: The X-ray Diffraction determined mineralogical results of the travertine rocks and some of the selected reddish-brown deposits.

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Supplementary table S2. Concentrations of trace elements (µg/L) in the water samples. The detection limits are shown in parentheses.

8

Supplementary figure captions

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Supplementary figure S1. The degree of enrichment of the target elements according to the normalized enrichment factor in comparison with the (a) bulk continental crust contents and (b) carbonate rocks.

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Co (0.2)

Ni (2)

Cu (0.2)

ICP-MS Mo Pb (0.1) (0.2)

71,400 45,300 44,600 90,400 12,500 74.6 69.5 59 350.4 1,100 71.4 100.1 203 85.8 1,043 9 2.5 2.5 1

0.48 0.15 0.11 2.07 2.64 0.21 BDL BDL 0.56 0.48 0.07 BDL 1.7 0.15 2.11 BDL 0.08 0.1 0.09

125.1 15.5 15.7 24.2 2.4 11.9 3.3 2.6 1.6 17 2 2.5 7.5 0.9 3.8 3.4 26.5 4 0.1

33.6 27.1 25.8 22 10.8 24.6 36 15.2 16.1 27.6 16 14.8 20.7 15.6 13 23 59 12 20

311.6 428.8 400.1 450.9 7.2 8.7 8 4.6 36.5 175.6 28.1 12.2 44.2 11.5 22.1 15.3 27 15 4

9.9 2 2 1.6 0.1 1.5 0.4 BDL 0.2 0.5 BDL 0.1 0.1 BDL 0.2 0.2 0.8 1 0.4

3 7 8 42 3 3 BDL BDL 1 3 BDL 2 1 BDL BDL 2 21.9 --1

Sb (0.1)

Tl (0.1)

Zn (0.2)

Se (0.05)

Cr (2)

45.1 9 9.1 21.7 0.1 0.3 0.2 0.2 0.3 0.6 BDL 0.1 0.1 0.1 0.5 0.2 0.2 -0.2

344.5 46 63.4 99.5 9.3 1.6 6.4 6.7 18 55.4 9.6 10.3 38.1 6.3 21.5 0.3 0.50 -0.2

235.9 134 130 106.6 536.9 31.1 13.8 13 61.6 39.4 8.1 9.6 87 7.3 372.6 18.8 72 25 20

0.17 0.19 0.24 0.84 0.11 0.13 BDL 0.06 BDL 0.19 0.07 0.12 0.13 0.13 0.08 0.08 0.13 0.08 0.08

11 24 29 <2 <2 2 <2 3 8 10 2 7 3 2 <2 16 135 10 11

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7.2 10.4 11.1 1.4 1584 2.4 0.3 2.5 0.6 1 0.2 1.6 11 0.2 74.9 5.3 11 8 9

Sc (1)

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Cd (0.05)

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Reddish-brown deposits Reddish-brown deposits Reddish-brown deposits Reddish-brown deposits Reddish-brown deposits Reddish-brown deposits Travertine Travertine Travertine Travertine Travertine Travertine Travertine Travertine Travertine Travertine Crustal abundance a Limestone b Carbonate rocks c a: Rudnick and Gao (2003) b: Levinson (1974) c: Mason and Moore (1982)

As (0.5)

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Sample Info.

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Table 1: Total contents of the target elements (mg/Kg) in the travertine and their associated reddish-brown deposits. The detection limits are shown in parentheses.

ICP-OES Fe S (100) (50)

141,000 82,000 83,000 179,000 13,820 25,500 817 1,320 2,420 12,400 830 4,490 3,850 575 1,960 7,690 50,000c -3,800

503 234 231 444 679 766 233 230 1,408 1,360 1,210 1,050 757 1,120 3,720 1,790 404 -1,200

Mn (2)

27048 2061 2134 6174 655 8306 251 245 226 1137 152 91 521 20 393 145 950 1100 1100

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Table 2. General hydro-geochemical parameters and concentration of arsenic in the water samples.

Concentration (mg/L)

Sample No.

Sample description

As (µg/L)

pH

Eh (mV)

T (ºC)

EC (µs/cm)

W1

Lalezar warm spring 1

30,300

6.4

41

37.6

12,000

W2

Lalezar warm spring 2

30,500

6.2

63

37.5

12,800

W3

Lalezar warm spring 3

30,300

6.5

41

38

W4

Khodadadi warm spring1

16,600

7.2

140

W5

Khodadadi warm spring2

15,900

7.2

141

Water type

CO3-2

Cl

SO4-2

Na

Ca

Mg

TDS

0

2,770

1,300

2,700

250.2

34

8,190

Na-Cl

1,360

0

2,840

1,450

2,940

193.3

36

8,590

Na-Cl

12,200

1,290

0

2,750

1,370

2,840

210.6

34

8,180

Na-Cl

25.2

9,900

1,440

0

1,760

1,400

2,120

160

70

6,950

Na-Cl

25.4

9,800

1,430

0

1,730

1,400

2,140

156

70

9,630

Na-Cl

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HCO3-

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1,290

cold mineral spring

192.2

7

219

24.5

2,700

1,640

0

268.9

69

338.2

282

78

1,970

W7

cold mineral spring

367.5

8

146

19.1

1,120

1,460

36.1

91.8

82.1

144.6

99

32

802

Na-HCO3

W8

Ab-Bakhsha River

506

7.8

225

12.4

1,790

365.5

0

253.9

275.5

285.3

158.4

21

1,250

Na-Cl

W9

Ab-Bakhsha River

126.3

8.6

W10

Ab-Bakhsha River

4.9

8.4

W11

cold natural spring

1.5

7.5

15.3

1,020

278.1

26.8

113.1

113.8

159.2

57.3

29

716

228

14.8

613

199.4

24.8

16.4

111.4

31.65

90.3

17.8

461

Ca-HCO3

220

12.4

340

188.9

0

10

18.8

12.86

51

8.5

214

Ca-HCO3 Ca-HCO3

1.5

7.4

225

12.8

342

194.1

0

11.5

24.3

12.24

52.5

9

266

WHO

10

6.5-9.5

--

--

--

--

--

250

500

200

--

--

--

U.S.EPA

10

6.5-8.8

--

--

--

--

--

250

250

--

--

--

--

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Drinking water standard

230

Na-HCO3

cold natural spring

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W6

Na-HCO3

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Asa --

Industrial effluents

Asa --

Decantation pound As pH 10 12.0 0.34 5 3.1 15

Water resources associated with Tailings dam Monitoring Oxidized tailings (old Safety bay wells impoundments) As pH As pH As pH 25.9 9.6 40 7.5 8.5 3.9 1.9 0.6 0.89 26.5 35.4 8.7

11.5 12.4

3.5 113

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pH As pH Mean 6.2 239 7.7 Standard 0.5 0.23 --110 deviation Min -3.1 -5.4 107 7.4 Max -5.1 -6.7 442 8.0 a: all values for As concentration are below detection limit (<5µg/L)

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Mining waters

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Rock waste drainages

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Table 3. Mean, standard deviation and range of As concentrations and pH values in different waters samples in the Sarcheshmeh copper complex

6.7 12.2

3.5 125

6.4 8.4

2.5 30.7

2.5 5.6

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ACCEPTED MANUSCRIPT Highlights Arsenic concentration was investigated in the old and active geothermal indicators. Very high arsenic content was measured in the reddish-brown deposits. Yukonite, a rare Ca ferric arsenate hydrous mineral, was identified. Arsenic concentration in the hydrothermal warm springs ranged from 15,900 to 30,500 µg/L. 5- High values of As, B, Cs, Fe, Li, Rb, Sb, Si, and Tl are good fingerprints for geothermal source.

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Reddish-brown deposits

S2 S3 S4 S5 S6 S7 S8 S9 S10

Reddish-brown deposits Reddish-brown deposits Reddish-brown deposits Reddish-brown deposits Travertine deposits Travertine deposits Travertine deposits Travertine deposits Travertine deposits

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Mineralogy calcite, quartz, pyrolusite (MnO2), yukonite [Ca7Fe3+12 (AsO4)10(OH)20 •15H2O] calcite, quartz, alb ite, alkali feldspar, hematite, mica calcite, yukonite quartz, calcite, hematite, mica quartz, calcite, amorphous material quartz, calcite quartz, calcite, hematite quartz, calcite, hematite aragonite, calcite quartz, calcite, aragonite

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Al Sample description

(1)

As (0.5)

B

Cs

(5)

(0.01 )

Cu (0.1)

Fe (0.01)

Li

Mn

Mo

Pb

Rb

S

Sb

Se

Si

Tl

Zn

(0.1)

(0.05 )

(0.1)

(0.1)

(0.01)

(1)

(0.05)

(0.5)

(40)

(0.01)

(0.5)

138

20

44,900

6.8

14.6

128

22.3

45,100

5.53

17.6

138

19

43,400

6.96

15.3

6.78

15.4

50,700

2.84

10.5

3.19

14.2

51,000

2.88

19.8

3.59

2.8

42,600

0.01

0.5

3.1

0.8

19,300

0

5.4

4.51

0.9

15,300

0.02

3

3.88

1

21,600

0

2

3.81

0

16,200

0

2.5

3.6

0

13,400

0

9.4

6.03

0

13,200

0

3.6

18

10

6

50

W1

Lalezar warm water 1

23

30,300

47,000

659

4.3

1,540

3,450

194

W2

Lalezar warm water 2

12

30,500

51,200

670

2.4

660

3,650

W3

Lalezar warm water 3

1

30,300

48,700

641

3.2

1,930

3,360

SC

Sample No.

RI PT

Supplementary table S2. Concentrations of trace elements (µg/L) in the water samples. The detection limits are shown in parentheses.

W4

Khodadadi warm spring1

3

16,600

33,000

252

6.3

160

2,360

438

W5

Khodadadi warm spring 2

73

15,900

33,800

252

9.5

220

2,350

W6

Cold mineral spring

39

192.2

4,711

0.35

0.4

5

W7

Cold mineral spring

46

367.5

1,398

0.07

4.2

80

Ab-Bakhsha River

26

506

2,840

0.76

2.5

14.1

658

220

17.4

0.2

722

196

16.1

13

683

36.5

0.4

352

451

31.1

7.3

348

6,58.0

0.13

0.7

< 0.1

4.6

192.7

5.61

0.7

3.3

1.38

M AN U

W8

17.2

10

163

3.2

4.1

0.5

7.64

1.6

5

87.3

1.78

1.5

0.5

0.44

Ab-Bakhsha River

24

126.3

838

W10

Ab-Bakhsha River

45

4.9

86

0.01

1.1

10

7.3

7.66

0.8

1.4

0.38

W11

cold natural spring

63

1.5

34

0.02

9.2

80

4.6

12.59

0.3

6.2

0.24

W12

cold natural spring

23

1.5

21

0.03

1.1

20

0

2.99

0.2

1.7

0.23

Water Standard

WHO

10

70

400

70

10

U.S.EPA

10

200

AC C

EP

TE D

W9

< 0.01

1000 1300

300

50

56 6 60 1 58 0 73 3 70 7 48. 4 60 12 1 83. 5 78. 7 23. 6 23

5000