JWARPJournal of Water Resource and Protection1945-3094Scientific Research Publishing10.4236/jwarp.2014.619160JWARP-52793ArticlesEarth&Environmental Sciences Chemical Evolution of Groundwater in the Dindefello Plain Area in South-Eastern Senegal eybatouDiop1*MoshoodN. Tijani2*Institute of Earth Sciences, Faculty of Sciences and Techniques, Cheikh Anta Diop University of Dakar, Dakar, SenegalDepartment of Geology, University of Ibadan, Ibadan, Nigeria* E-mail:seybdiop@yahoo.fr(ED);tmoshood@yahoo.com(MNT);3012201406191793181519 November 201410 December 2014 26 December 2014© Copyright 2014 by authors and Scientific Research Publishing Inc. 2014This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/

This study was to clarify the main mechanisms of shallow groundwater mineralization in the Dindefello Plain Area. Water composition data obtained in this study were subjected to aqueous speciation calculations together with data plotting on key diagrams so as to create work assumptions. Hypothesized reaction models of the processes of chemical weathering of carbonates and silicate minerals under the carbon dioxide regime were proposed and tested by selecting two water sample analyses interpreted as “starting” and “ending” water composition along a hydrologic flow line, and then running the PHREEQC (version 2) batch modeling procedure, to simulate chemical balances and compositional variations of groundwater within the geochemical system. For the flow path data discussed here, there was close agreement between the model results and the observed hydrochemistry, and so the proposed geochemical evolution model was deemed reliable.

Senegal Dindefello Groundwater Mineralization Springwater Geochemical Modeling1. Introduction

The composition of groundwater is an important source of hydrogeochemical information about earth surface weathering processes [1] . Hence, knowledge of the solute constituents could aid in reconstructing the major chemical reactions contributing to groundwater mineralization ( [2] - [8] ). The purpose of the exercise was to demonstrate a proposed hypothesis of Diop et al. [9] , that the main control on groundwater mineralization in the near surface aquifers of the DPA hydrologic system (hereinafter referred to as DPA-HS) is the pH-driven process of mineral breakdown (mainly carbonates and silicates), under the carbon dioxide regime. This paper is based on the interpretation of water composition data presented by these authors, and it follows a two-step procedure.

In the first instance, key diagrams pertinent for inferring the hydrogeochemical evolution of groundwater in the DPA-HS are presented, and then the batch modeling procedure of PHREEQC computer program (version 2, [10] ) to reconstruct the hypothesized reaction models is run. In essence, this simulated the specific case that recharge spring water infiltrating into the ground interacts along its flow paths with calcite, dolomite and albite minerals under “open-system conditions” [4] to account for the observed chemical composition of groundwater downstream.

2. Location and Hydrogeology

The study area is located on the Senegal-Guinea Republic border, between longitude 12˚20'W - 12˚25'W and latitude 12˚20'N - 12˚25'N, within a region referred to here as the “Dindefello Plain Area”―DPA.

The DPA is a poorly documented depression bounded to the south by a range of hills rising to over 400 m above the surrounding terrain, with maximum elevations approximately 450 m above MSL (Figure 1). Fracture and contact springs are found at the margins of the top of the plateau and its foothills. The regional structures are components of the Fouta Djalon Mountains chain (Guinea Republic), which is emplaced on the southern prolongation of the Mauritanides fold belt ([11] [12] ). Organically, the Mauritanides belt flanks the 2 × 109

Location map of the study area within south-eastern Senegal

years old West African craton to the west ( [13] [14] ). Rocks underlying the DPA, or outcropping, are mainly young basement rocks of the Ségou-group ([15] -[18] ) which contain mineralogical groupings (carbonaceous limestones and dolostones and feldspatic sandstones assemblages) that are source of major ions in the groundwater of the study area.

The groundwater system underlying the DPA comprises the low-permeability regolith zone (upper aquifer unit with the water table mostly 10 - 30 m below ground surface), and the more productive adjacent zone reservoir of bedrock disintegration and leaching (lower aquifer unit). There is interaction between this system and the topography-driven spring water system that flows out of the uplands and avalanches down into the plain area.

Recharge to the subterranean drainage system occurs on a yearly basis, as spring discharges cascade down onto the valley floors and drain into pathways incised by the river system, and remain in the channel over a long distance. However, the low permeability character of the superficial regolith reduces the effectiveness of direct rainwater infiltration. Thus, groundwater is recharged locally and essentially by runoff in the alluvium of rivers and their tributaries, which have eroded their ways into the plain floor. Spring water percolating downward through the alluvium of river channels reaches the groundwater table, thereby forming a major source of groundwater recharge. The hydrodynamic regime of the hydrologic system is topography-driven and the land surface can be used to infer groundwater flow patterns, assuming that the water table is a subdued replica of the surface topography.

In the study area domestic water supply is typically obtained from shallow hand-dug wells bored in the regolith zone reservoir, down to depths of 20 - 30 m below ground surface. The water level in these wells can rise 10 m during the rainy season and then can fall almost rapidly. However, a more permanent supply is reached by motor-driven wells that penetrate the deeper seated fractured zone reservoir. During the rainy season from May to October, this region receives about 1200 mm rainfall, of which nearly 20% may result as net rain [19] . During the dry season, surface water sources are very limited, and the depth of groundwater is relatively great (often >25 - 30 m). To meet their water needs in this period, people most frequently collect water from springs and pondlets dug on stream beds.

3. Materials and Methods

Traditionally, the geochemistry of groundwater can be used to reconstruct the controlling processes of mineral dissolution. Theories on the origin of groundwater mineralization generally agree that when water comes into contact with minerals, chemical weathering and dissolution of the minerals begins and continues until equilibrium concentration is attained in the water, or until all minerals are consumed [4] . Thus, depending on the environment, chemical and mineralogical characteristics of the rocks which groundwater has come into contact with during its flow history, its chemistry may be altered to reflect the host rocks. Because of this, one inclination might be to use the equilibrium concept as a means of interpreting chemical data. So, if water samples need to be to checked as to how far the hypothetical reactions have proceeded to give their hydrochemistry, their SIs with respect to these minerals should be calculated. For a given water sample, its SI with respect to any candidate source or sink mineral can be computed, based on the ionic product for the aqueous phase and its equilibrium constant at the considered temperature.

It is not intended here to describe the theoretical background (for more details, see [4] , [20] or [21] ), but, instead, to note that the saturation state for a particular mineral (considered as possible source or sink of ions to aqueous solution), or other participating substance is expressed as saturation index (SI), [20] :

where:

Iap: ionic activity product

KT: mineral equilibrium constant at the specified temperature.

• For SI > +0.1, the specific mineral is supersaturated, and precipitation is possible;

• For −0.1 < SI < +0.1, the specific mineral is saturated and precipitation or dissolution possible; and

• For SI < −0.1, the specific mineral is undersaturated, and dissolution possible.

The approach taken was to first carry out exploratory investigations for mineral-water relationships from the analyzed data so as to create work assumptions, and then use the computer program PHREEQC (http://water.usgs.gov/software/) to check these assumptions.

The data used for this study (Table 1) were essentially the major elements’ chemistry of water samples from springs, water supply pondlets dug by villagers on stream beds and village hand-dug wells. Figure 2 conveys the areal distribution of the various samples. Supplementary data included the chemical composition of rainfall [22] which was found to be available and so allowed comparison with spring water (Table 1), as well as compiling qualitative data about the nature of the physical environment. This enabled approximating groundwater flow patterns to be drawn (by assuming that the water table is controlled by the surface topography), thus providing a comprehensive inventory of potential reactants for the proposed geochemical model evolution.

4. Results and Discussions4.1. Analysis of Trend

The data employed in this study is as presented in Table 1. The waters have acidity at near neutral pH (4.65 ≤ pH ≤ 6.93), and total mineralization (TDS) ranged from 20 to 570 mg/L. The five elements, SiO2, Ca2+, Mg2+ and Na+, in order of decreasing abundance, make up the bulk of mineralization. These elements represent over 80% - 90% of the TDS. In a general way, subsurface groundwater (i.e. water samples from hand-dug wells) has much higher mineralization than spring water, which shows near-local rainwater characteristics. The consistently lower mineralization of spring water indicated rapid drainage of meteoric waters through the high permeability pathways provided by rock fractures, joints, bedding planes and faults in the highlands. This rapid flow results in shorter residence time and less mineral-water interaction in the host rocks. However, anomalously high TDS of some springs (Pr3 and 14) and pondlets (Pr4 and 5) revealed the influence of marshy conditions prevailing at these locations where water may be acidic from CO2 production (from organic matter decay) leading to increased solubility. In contrast, groundwater travelling in the plain aquifers generally had increasing levels of dissolved solids with distance down gradient as a result of chemically evolved recharge waters from longer residence time. Consequently, a model of hydrochemical evolution must explain the increase in dissolved solids, and hence the evolution of recharge spring water (or meteoric water), as it avalanches down onto the valley floor and infiltrates into the ground to become subsurface groundwater.

Moreover, Table 1 shows that the higher its mineralization grade (column 3), the more groundwater is approaching equilibrium/saturation with respect to calcite, dolomite and aqueous silica (column 13 to 20). It seems reasonable, therefore, to suggest these three minerals as possible sources of dissolved constituents for groundwater. Figure 2 and Figure 3 represent key diagrams as regards the geochemical conditions giving rise to groundwater chemistry.

Figure 3 indicates the major compositional water types observed by plotting the samples in a Piper diagram whereby the circle radius is a scale for TDS. The chemical composition of most spring samples shows a minor nitrate and chloride impairment (possibly due to human impact), that causes them to vaguely shift along the (SO4 + Cl + NO3)-axis of the lozenge and slightly obfuscate the evolutionary path for cations. The grouping shows:

1) Waters whose solutes are dominated by; These are waters in which calcium and magnesium amount 50% or more of the cation budget, and bicarbonate to more than 50% of the anions. They are typical of recharge water into carbonate hosted lithology, viz. a geological environment containing calcite and dolomite whereby the characteristically high levels suggest the geochemical implication of gas as a controlling factor.

2) Waters that are relatively enriched in alkali ions, comprising two cases of sodium bicarbonate end-member type,; Theses are waters in which milliequivalents of [Na+ + (K+)] and contribute each more than 50% of the ion budget. They are distributed along the (Na + K)-axis of the Piper diagram in Figure 3, a distribution pattern that suggests chemically evolved type (1) waters through contemporaneous interaction with silicate rocks.

Figure 4 shows in this respect that the water composition, expressed in terms of SiO2 and Na+/H+, plots towards the boundary between kaolinite-Na-monmorillonite for spring waters, as compared to groundwater that characteristically evolves to the albite boundary as mineralization proceeds. Presumably albite dissolves incongruently to produce dissolved SiO2 and Na in spring waters in the early stage of mineralization, and both kaolinite and Na-montmorillonite as secondary minerals by-products. The kaolinitic and Na-montmorillonitic by- products may dissolve subsequently as groundwater mineralization progresses. Several authors ([1] [3] [7] ) have observed this behavior pattern in igneous terrains where most groundwater-derived surface waters, such as

Location of the sampling sites within the DPA physiographic region. Note: The arrow indicates the simulated reaction flow path. Refer to <xref ref-type="fig" rid="fig1">Figure 1</xref> for the location of Pr13 (Tiangué Village). Piper diagram for the various water samples from the DPA- HS, with TDS as circles. Note: Triangles are springs water samples and circles represent groundwater samples Stability diagram for gibbsite, kaolinite, montmorillonite and albite at 25˚C. Note: Triangles are samples from springs, and circles re- present samples from groundwater

springs and baseflow, plot in the kaolinite fields of stability of this diagram type.

In Figure 5 the water chemistry expressed in terms of pH and is compared to the simple open-sys- tem dissolution model of [4] describing the evolution pattern of groundwater in contact with calcite at 15˚C and under various partial pressures. It is obvious in this figure that all water samples plot above the atmospheric CO2 partial pressure () level of 10−3.5 bar; viz. within levels in ranges 10−1 - 10−3 bar which are at least 30-times the atmospheric level. This clearly means that water infiltrating through the aquifer soil zones become charged with CO2 gas that normally makes water acidic and prone to weathering. Indeed, CO2 normally reacts with water to form carbonic acid (H2CO3 ), which initiates geochemical reactions in groundwater.

It is obvious in Figure 5 that spring waters occur with the lowest values of pH and, while groundwater samples plot on a position near the calcite saturation line, thereby evolving within paths lines in the range roughly from 10−1 to 10−2 bar. Furthermore, the comparison in Figure 5 also shows a regular increase in with increasing pH (in the range 6 - 7) of groundwater where the higher its CO2 partial pressure, the more groundwater is nearing equilibrium with respect to calcite. It is very likely that the hydrologic field situation for the dissolution of calcite to proceed roughly follows the evolution pattern described by the arrow. This trend has been interpreted to mean the conventional view point that more calcite dissolution leads to higher H+ consumption and, therefore, to higher pH and values, all according to the reaction: .

As the dissolution reaction for calcite proceeds, consumption of H+ (equivalent to a pH rise) normally causes the concentration of H2CO3 to decline however (according to: ) by fairly uniform CO2 partial pressure within the range 10−1 - 10−2 bar. This implies that replenishment of the CO2 stock (a CO2 refill process from outside the system) must occur simultaneous as dissolved CO2 is destroyed progressively on dissolution of calcite. Presumably, spring water regularly seeping into the ground as recharge water is an important source of CO2 for groundwater. However, reaction types that tend to prevent a partial pressure drop within the system may include the conversion of calcite to wollastonite: [23] and this factor is not included in this discussion. It is worth noting from the development above that is from two different sources: 1) ionization of H2CO3 ( ), and 2) reaction of H+ with calcite ( ), which probably explains its predominance in groundwater.

Additional sources of solute constituents in groundwater may include the weathering of other silicate compounds known to be present in the soil zone (e.g., potassium feldspar-KAlSi3O8) which is much less reactive than sodium feldspar―NaAlSi3O8 [2] . Also, aluminosilicate/clays minerals, as well as the dissolution of gypsum and cationic exchange, could be sources of solute in groundwater. Representing these reactions ( [4] [5] ) as in Table 2 supports the contention that these are, perhaps, the more likely reactions to consider in explaining the major-ion chemical evolution of groundwater in the DPA. These reactions fairly illustrate how H+ ions might be

Plot of <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/6-9402389x31.png" xlink:type="simple"/></inline-formula> as a function of pH according to the open-system dissolution model of Freeze and Cherry [<xref ref-type="bibr" rid="scirp.52793-ref4">4</xref>] . Note: Triangles are springs water samples and rectangles represent groundwater samples: The waters approach calcite saturation as dissolved <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/6-9402389x31.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/6-9402389x32.png" xlink:type="simple"/></inline-formula> and H<sup>+</sup> increase Set of possible chemical reactions which may control the hydrochemistry in aquifers of the DPA

produced and consumed upon dissolution of the hypothesized minerals to result in the observed major ions’ chemistry of groundwater.

4.2. Flow Path Modeling

The present research strongly suggests the CO2-driven process of mineral weathering as being the most likely mechanism in controlling the hydrochemical evolution in the DPA. This is in keeping with the established views ([23] [24] ) that CO2-charged recharge waters from rain percolating into subsurface soils naturally dissolve mineral materials during their underground movement. The mechanisms occur either by equilibrium with soil zone CO2 reservoir (or so-called “open system” conditions) or isolated from this reservoir (“closed system” conditions).

In the following assessment, the computer program PHREEQC (version 2; [10] ) was used to investigate the control of hypothesized reactions on the water chemistry. This involved modelling the specific case where spring waters that are chemically identical to rain waters infiltrating at foothills (around sampling site Pr1), interact along their flow paths with the said minerals (viz. calcite, dolomite, albite and gibbsite) under “open-system” conditions to produce the major ion composition of groundwater sampled from a hand-dug well at site Pr15 (Pelel village), at about 3.5 km downstream of Pr1; (refer to Figure 2 for the considered flow direction). This means that PHREEQC calculates speciation and moles of specified minerals and gas phases that would react with water sample Pr1 (initial solution) to produce an aqueous solution (final solution) whose mineral phases’ SIs with respect to the considered match those for water sample Pr15.

The steps for the model implementation (see Appendix) are: 1) Definition of the numerical entities for running the model; 2) Input of the required information; and 3) Execute the simulation.

Once the calculations have been fulfilled to target saturation constraints (as defined by the modelling procedure under the heading “EQUILIBRIUM PHASES 1”; see Box 1 of List 1 in the Appendix), PHREEQC displays the output results.

The output file is lengthy and contains a wealth of information that is not presented here for the sake of brevity. For more details, see List 1 (Appendix), where the focal outcome is given in Box 3, under the subheadings “Phase assemblage” and “Solution composition”. Moreover, the chemical analysis of Pr15 was also included in the model for comparison with results of PHREEQC speciation for the output solution (see Box 4.2 of List 1 in the Appendix). As can be viewed from the comparison therein, the model reproduces the observed water chemistry reasonable well.

Table 3 is a shortcut for this comparison. It should be noted that the ionic increase from sample Pr1 to sample Pr15 was modelled (see column 2 of the table) as a down-gradient chemical change in the aquifer due to a greater magnitude of water-mineral-interaction along flow path; essentially carbonate and silicate minerals. Clearly, the model results (column 2) are in good agreement with the chemistry of the groundwater collected at site Pr15 (column 3). An illustration of the good quality of the prediction is given in Figure 6 which shows the coefficient of correlation as 0.999, proving that the model reasonably reproduced the observed water chemistry.

Table 4 contains results from the mass balance. As can be seen, the amount of dissolved albite almost equals that of gibbsite that precipitates, indicating an inverse process. However, the (slight) discrepancy between the Na+ content generated by the model and the observed one (see also Table 3) suggests other sources of Na in solution, like cationic exchange process. In contrast to Na, predicted and observed concentration for both Ca and Mg match quite well.

Moreover, Table 4 provides an estimate of the contribution of dissolved CO2 to alkalinity ( ). The value so determined is 2.27 mmol/L (99.88 mg C/L as CO2), a plausible range of CO2 gas in the soil zone [20] . For the studied case, input CO2 gas provides nearly 42% of the total alkalinity source, which demonstrates its important role in the mineralization of groundwater in the considered system.

Overall, the stated mass balance would mean that the down-gradient well chemistry at sampling location Pr15 equals the up-gradient spring water chemistry at location Pr1 plus phases dissolving, minus phases precipitating. However, precipitation is negligible, as is the case for gibbsite (see List 1). For instance, the total alkalinity con- centration (405.46 mg C/L) given in Table 3 for sample Pr15 should be equal to the up-gradient carbon concentration of sample Pr1 (=14.13 mg C/L), plus the carbon from calcite and dolomite dissolution [3.21 mmole × 60 g/mole = 192.6 mg C/L] plus the carbon from dissolution of aqueous CO2 [2 × 2.27 mmole CO2 × 44 g/mole = 199.76 mg C/L] = 406.49 mg C/L. The two values agree well, as can be inferred from results of the mass balances calculations shown on Table 4.

Set of element concentrations essential for corroborating model results
ElementsInput solution (Pr1)Model outputObs. composition (Pr15)
mg/L (mmol/L)mg/L (mmol/L)mg/L (mmol/L)
Ca1.92 (4.79E−02)86.80 (2.16E+00)88.24 (2.20E+00)
Mg0.51 (2.10E−02)13.57 (5.59E−01)13.47 (5.54E−01)
Na0.28 (1.22E−02)6.41 (2.79E−01)9.51 (4.14E−01)
C (as CO2)14.13 (3.21E−01)405.46 (9.22E+00)408 (9.28E+00)
Si (as SiO2)16.77 (2.79E−01)64.80 (1.08E+00)57.12 (9.51E−01)
Al0.02 (7.41E−04)0.0010 (3.74E−05)0.0010 (3.71E−05)

Note: The ionic increase from sample Pr1 to sample Pr15 was modeled (column 2) as evolutionary change in the aquifer due to a greater magnitude of water-mineral-interaction along flow path; essentially carbonate and silicate minerals.

Correlation between the observed and modeled six elements’ concentrations: Note: The fitted line is not statistically distinct from the line of one-to-one Selected results from the mass balance calculations
Selected dataWater sampleMass transfer: Pr1 Þ Pr15
Pr1Pr15
SIAlbite−4.54−1.86D(SI) = 2.68
(Albite dissolution = 2.667E−01 mmoles)
D(Na+): +9.23 mg/L (0.40 mmol/L)
SICalcite−4.49−0.53D(SI) = 3.96
(Calcite dissolution = 1.578E+00 mmoles)
D(Ca2+): +86.32 mg/L (2.16 mmol/L)
SIDolomite−9.28−1.58D(SI) = 7.70
(Dolomite dissolution: 5.38 E−01 mmoles)
D(Mg2+): +12.96 mg/L (0.53 mmol/L)
SIGibbsite−1.11−2.16D(SI) = −1.05
(Gibbsite precipitation: 2.67E−01 mmoles)
D(Al3+): −0.019 mg/L (−0.0007 mmol/L)
−2.21−1.04D(SI) =1.17
(CO2(gas) dissolution: 6.24E+00 mmoles)
D(C/alkalinity as CO2): +393.87 mg C/L (+8.95 mmol C/L)
Balance calculation for total alaklinity
Change in alkalinity along flow path Pr1 → Pr15: (): +334.10 mg/L (+5.48 mmol/L)
released from (Calcite + Dolomite) dissolution: 2.15 + 2*0.53 = 3.21 mmoles/L (192.60 mg/L)
D() from dissolution of CO2 (g) (H2CO3H++ ): 5.48 - 3.21 = 2.27 mmol/L (99.88 mg/L)
Alkalinity balance: 192.60 mg C as + (2*99.88 mg C as) = 392.36 mg C/L (8.91 mmol C/L)

Note: Changes in saturation state D(SI) indicate possible chemical reaction of the specific mineral phase in the aquifers. A positive value implies mineral dissolution and a negative value indicates mineral precipitation.

5. Conclusions

In terms of the interpretation of the major ion loading of groundwater in the DPA and the geochemical reactions paths modelling, the conclusions of this study are as follows:

1) Chemical data analysis through graphical plots and aqueous speciation calculations revealed that the predominant groundwater reactions were the carbon dioxide-driven processes of carbonate and silicate minerals weathering that produced the calcium-magnesium-bicarbonate and sodium-bicarbonate waters which showed near saturation with respect to the minerals calcite and dolomite and albite among others; and

2) The PHREEQC batch modelling, which simulated the observed flow path data, supported the hypotheses on the stages of hydrogeochemical evolution of groundwater.

Acknowledgements

The work benefitted significantly from discussions with Prof. Dr. F. Wisotzky of the RU Bochum (RFG), who we wish to thank.

Appendix

In this appendix details are given of the model implementation and output result (List 1, below). More details on the computation procedure can be found in the tutorial [9] .

The heading “Reading data base” (Bloc 1) defines the algorithms here used for simulating the reactions path. The heading “Reading input data for simulation 1” (Bloc 2) introduces the essential data supplied to the model, namely: the initial solution (SOLUTION 1), representing hereinafter water sample Pr1 and the set of phases (“EQUILIBRIUM PHASES 1”) that are supposed to react during the batch reaction to turn the initial solution to a mineral saturation state matching that of water sample Pr15 (final solution). Thus, the keyword “SOLUTION 1” defines the composition of sample Pr1 and “EQUILIBRIUM PHASES 1” is the keyword that declares the list of phases used in the model and their respective SI. These so-called “target SIs values” were anticipated from a PHREEQC speciation of water sample Pr15. They are entered in the model to thermodynamically constraints the system. So conceptually, we consider the chemical balance that would result if water sample Pr1 were placed in a beaker which is regulated at 20˚C and allowed to react with the specified minerals and gas phases until the saturation limits are attained.

“Beginning of initial solution calculations” (Bloc 3) specifies the conversion of the input concentration data for Pr1 into molality (subheading “solution composition”). Subheading “Description of solution” introduces some basic properties calculated by the model. Subheading “Distribution of species” lists the different elements (master species) and amount of corresponding aqueous species in the solution. Subheading “Saturations indices” lists the SI calculations for all minerals that are appropriate for the aqueous solution and their respective formula.

The heading “Beginning of the batch reaction” (Bloc 4) defines the beginning of the batch reaction calculations for the simulation. When the simulation begins the initial solution and pure phases are put together and allowed to react until the saturation limits utilized to thermodynamically constraint the system (stated target SI values) are attained. The proportion of reactant is one mole for each mineral phase.

After the calculations are completed, the numbers of moles consumed for the reactions (mass transfers) are presented under subheading “Phase assemblage” (see Bloc 4.1; whereby positive delta value indicates precipitation and negative delta value dissolution). The resulting water chemistry (output or final solution) is then computed the (see subheading “Solution composition”; Bloc 4.2). Next, PRHEEQC calculates the resultant aqueous speciation (see subheading “Distribution of species”, Bloc 4.4) and then provides SIs for possible and impossible sources or sinks of solutes (see Subheading “Saturation indices”, Bloc 4.5).

List 1: Output data file for the modeled flow path

Input file: phreeqc.tmp

Output file: C:\Programme\Phreeqc\senegal1.out

Database file: C:\Programme\Phreeqc\Phreeqc.dat

------------------

Reading data base. (BLOC 1)

------------------

SOLUTION_MASTER_SPECIES

SOLUTION_SPECIES

PHASES

EXCHANGE_MASTER_SPECIES

EXCHANGE_SPECIES

SURFACE_MASTER_SPECIES

SURFACE_SPECIES

RATES

END

------------------------------------

Reading input data for simulation 1. (BLOC 2)

------------------------------------

TITLE Analyse Senegal Pr. 1 (BLOC 2.1)

SOLUTION 1

units mg/l

pH 5.89

pe 4.0

density 1.000

temp 20.0 # estimated

Ca2+ 1.92

Mg2+ 0.51

Na+ 0.28

K+ 0.43

Fe2+ 0.001

Mn2+ 0.001

Sr2+ 0.001

Cl- 0.98

C 14.13 as CO2 # from ionic balance

S6+ 1.27

N5+ 1.43 as NO3-

Si4+ 16.77 as SiO2

Al3+ 0.02

B3+ 0.22

EQUILIBRIUM_PHASES 1 (BLOC 2.2)

Calcite -0.53

Dolomite -1.58

Albite -1.86

Al(OH)3(a) -2.16

CO2(g) -1.04

END

-----

TITLE Analyse Senegal Diop Pr. 1

-----

-------------------------------------------

Beginning of initial solution calculations. (BLOC 3)

-------------------------------------------

Initial solution 1.

------------------Solution composition--------------(BLOC 3.1)----

Elements Molality Moles

Al3+ 7.413e-07 7.413e-07

B3+ 2.035e-05 2.035e-05

C4+ 3.211e-04 3.211e-04

Ca2+ 4.791e-05 4.791e-05

Cl- 2.764e-05 2.764e-05

Fe3+ 1.791e-08 1.791e-08

K+ 1.100e-05 1.100e-05

Mg2+ 2.098e-05 2.098e-05

Mn2+ 1.820e-08 1.820e-08

N5+ 2.306e-05 2.306e-05

Na+ 1.218e-05 1.218e-05

S6+ 1.322e-05 1.322e-05

Si4+ 2.791e-04 2.791e-04

Sr2+ 1.141e-08 1.141e-08

----------------------Description of solution------------- (BLOC 3.2)----

pH = 5.890

pe = 4.000

Activity of water = 1.000

Ionic strength = 2.415e-04

Mass of water (kg) = 1.000e+00

Total alkalinity (eq/kg) = 7.951e-05

Total CO2 (mol/kg) = 3.211e-04

Temperature (deg C) = 20.000

Electrical balance (eq) = 6.611e-06

Percent error, 100*(Cat-|An|)/(Cat+|An|) = 2.07

Iterations = 10

Total H = 1.110137e+02

Total O = 5.550824e+01

--------------------Distribution of species-------------- (BLOC 3.3)---

Log Log Log

Species Molality Activity Molality Activity Gamma

H+ 1.311e-06 1.288e-06 -5.882 -5.890 -0.008

OH- 5.364e-09 5.270e-09 -8.270 -8.278 -0.008

H2O 5.551e+01 1.000e+00 1.744 -0.000 0.000

Al 7.413e-07

Al(OH)2+ 4.905e-07 4.819e-07 -6.309 -6.317 -0.008

AlOH2+ 1.333e-07 1.242e-07 -6.875 -6.906 -0.031

Al(OH)4- 5.279e-08 5.186e-08 -7.277 -7.285 -0.008

Al(OH)3 3.767e-08 3.767e-08 -7.424 -7.424 0.000

Al+3 2.614e-08 2.238e-08 -7.583 -7.650 -0.068

AlSO4+ 8.210e-10 8.066e-10 -9.086 -9.093 -0.008

Al(SO4)2- 3.087e-13 3.033e-13 -12.510 -12.518 -0.008

AlHSO42+ 9.493e-17 8.844e-17 -16.023 -16.053 -0.031

B 2.035e-05

H3BO3 2.034e-05 2.035e-05 -4.692 -4.692 0.000

H2BO3- 8.430e-09 8.282e-09 -8.074 -8.082 -0.008

C(-4) 0.000e+00

CH4 0.000e+00 0.000e+00 -57.660 -57.660 0.000

C(4) 3.211e-04

CO2 2.417e-04 2.417e-04 -3.617 -3.617 0.000

HCO3- 7.927e-05 7.789e-05 -4.101 -4.109 -0.008

CaHCO3+ 4.136e-08 4.064e-08 -7.383 -7.391 -0.008

MgHCO3+ 1.773e-08 1.742e-08 -7.751 -7.759 -0.008

CO32- 2.732e-09 2.546e-09 -8.564 -8.594 -0.031

NaHCO3 5.241e-10 5.241e-10 -9.281 -9.281 0.000

CaCO3 1.738e-10 1.738e-10 -9.760 -9.760 0.000

FeHCO3+ 1.310e-10 1.287e-10 -9.883 -9.890 -0.008

MnHCO3+ 1.189e-10 1.168e-10 -9.925 -9.933 -0.008

MgCO3 4.386e-11 4.386e-11 -10.358 -10.358 0.000

SrHCO3+ 1.084e-11 1.065e-11 -10.965 -10.973 -0.008

MnCO3 3.402e-12 3.403e-12 -11.468 -11.468 0.000

FeCO3 1.009e-12 1.010e-12 -11.996 -11.996 0.000

NaCO3- 4.468e-13 4.390e-13 -12.350 -12.358 -0.008

SrCO3 1.487e-14 1.487e-14 -13.828 -13.828 0.000

Ca 4.791e-05

Ca2+ 4.776e-05 4.451e-05 -4.321 -4.352 -0.031

CaSO4 1.031e-07 1.031e-07 -6.987 -6.987 0.000

CaHCO3+ 4.136e-08 4.064e-08 -7.383 -7.391 -0.008

CaCO3 1.738e-10 1.738e-10 -9.760 -9.760 0.000

CaOH+ 5.837e-12 5.734e-12 -11.234 -11.242 -0.008

CaHSO4+ 7.465e-13 7.334e-13 -12.127 -12.135 -0.008

Cl 2.764e-05

Cl- 2.764e-05 2.716e-05 -4.558 -4.566 -0.008

MnCl+ 1.894e-12 1.861e-12 -11.723 -11.730 -0.008

FeCl+ 6.306e-13 6.196e-13 -12.200 -12.208 -0.008

MnCl2 2.206e-17 2.206e-17 -16.656 -16.656 0.000

FeCl2+ 8.950e-21 8.338e-21 -20.048 -20.079 -0.031

MnCl3- 1.680e-22 1.650e-22 -21.775 -21.782 -0.008

FeCl2+ 1.210e-24 1.188e-24 -23.917 -23.925 -0.008

FeCl3 3.227e-30 3.227e-30 -29.491 -29.491 0.000

Fe(2) 1.790e-08

Fe2+ 1.773e-08 1.653e-08 -7.751 -7.782 -0.030

FeHCO3+ 1.310e-10 1.287e-10 -9.883 -9.890 -0.008

FeSO4 3.260e-11 3.261e-11 -10.487 -10.487 0.000

FeOH+ 2.824e-12 2.774e-12 -11.549 -11.557 -0.008

FeCO3 1.009e-12 1.010e-12 -11.996 -11.996 0.000

FeCl+ 6.306e-13 6.196e-13 -12.200 -12.208 -0.008

FeHSO4+ 2.772e-16 2.723e-16 -15.557 -15.565 -0.008

Fe(3) 1.038e-11

Fe(OH)2+ 9.574e-12 9.406e-12 -11.019 -11.027 -0.008

Fe(OH)3 7.535e-13 7.536e-13 -12.123 -12.123 0.000

FeOH2+ 4.764e-14 4.438e-14 -13.322 -13.353 -0.031

Fe(OH)4- 4.426e-16 4.349e-16 -15.354 -15.362 -0.008

Fe3+ 1.396e-17 1.194e-17 -16.855 -16.923 -0.068

FeSO4+ 1.450e-18 1.425e-18 -17.839 -17.846 -0.008

FeCl2+ 8.950e-21 8.338e-21 -20.048 -20.079 -0.031

Fe(SO4)2- 3.787e-22 3.721e-22 -21.422 -21.429 -0.008

FeHSO42+ 5.307e-24 4.944e-24 -23.275 -23.306 -0.031

FeCl2+ 1.210e-24 1.188e-24 -23.917 -23.925 -0.008

Fe2(OH)24+ 8.683e-26 6.540e-26 -25.061 -25.184 -0.123

FeCl3 3.227e-30 3.227e-30 -29.491 -29.491 0.000

Fe3(OH)45+ 3.199e-34 2.055e-34 -33.495 -33.687 -0.192

H(0) 2.378e-23

H2 1.189e-23 1.189e-23 -22.925 -22.925 0.000

K 1.100e-05

K+ 1.100e-05 1.080e-05 -4.959 -4.966 -0.008

KSO4- 8.608e-10 8.457e-10 -9.065 -9.073 -0.008

KOH 2.907e-14 2.908e-14 -13.536 -13.536 0.000

Mg 2.098e-05

Mg2+ 2.091e-05 1.949e-05 -4.680 -4.710 -0.030

MgSO4 4.880e-08 4.881e-08 -7.312 -7.312 0.000

MgHCO3+ 1.773e-08 1.742e-08 -7.751 -7.759 -0.008

MgCO3 4.386e-11 4.386e-11 -10.358 -10.358 0.000

MgOH+ 3.533e-11 3.471e-11 -10.452 -10.460 -0.008

Mn(2) 1.820e-08

Mn2+ 1.805e-08 1.682e-08 -7.744 -7.774 -0.030

MnHCO3+ 1.189e-10 1.168e-10 -9.925 -9.933 -0.008

MnSO4 3.305e-11 3.306e-11 -10.481 -10.481 0.000

MnCO3 3.402e-12 3.403e-12 -11.468 -11.468 0.000

MnCl+ 1.894e-12 1.861e-12 -11.723 -11.730 -0.008

MnOH+ 2.257e-13 2.218e-13 -12.646 -12.654 -0.008

Mn(NO3)2 3.477e-17 3.477e-17 -16.459 -16.459 0.000

MnCl2 2.206e-17 2.206e-17 -16.656 -16.656 0.000

MnCl3- 1.680e-22 1.650e-22 -21.775 -21.782 -0.008

Mn(3) 2.901e-30

Mn3+ 2.901e-30 2.474e-30 -29.537 -29.607 -0.069

N(5) 2.306e-05

NO3- 2.306e-05 2.266e-05 -4.637 -4.645 -0.008

Mn(NO3)2 3.477e-17 3.477e-17 -16.459 -16.459 0.000

Na 1.218e-05

Na+ 1.218e-05 1.197e-05 -4.914 -4.922 -0.008

NaSO4- 7.196e-10 7.070e-10 -9.143 -9.151 -0.008

NaHCO3 5.241e-10 5.241e-10 -9.281 -9.281 0.000

NaCO3- 4.468e-13 4.390e-13 -12.350 -12.358 -0.008

NaOH 6.136e-14 6.136e-14 -13.212 -13.212 0.000

O(0) 0.000e+00

O2 0.000e+00 0.000e+00 -48.205 -48.205 0.000

S(6) 1.322e-05

SO42- 1.307e-05 1.218e-05 -4.884 -4.915 -0.031

CaSO4 1.031e-07 1.031e-07 -6.987 -6.987 0.000

MgSO4 4.880e-08 4.881e-08 -7.312 -7.312 0.000

HSO4- 1.395e-09 1.370e-09 -8.855 -8.863 -0.008

KSO4- 8.608e-10 8.457e-10 -9.065 -9.073 -0.008

AlSO4+ 8.210e-10 8.066e-10 -9.086 -9.093 -0.008

NaSO4- 7.196e-10 7.070e-10 -9.143 -9.151 -0.008

MnSO4 3.305e-11 3.306e-11 -10.481 -10.481 0.000

FeSO4 3.260e-11 3.261e-11 -10.487 -10.487 0.000

SrSO4 2.371e-11 2.371e-11 -10.625 -10.625 0.000

CaHSO4+ 7.465e-13 7.334e-13 -12.127 -12.135 -0.008

Al(SO4)2- 3.087e-13 3.033e-13 -12.510 -12.518 -0.008

FeHSO4+ 2.772e-16 2.723e-16 -15.557 -15.565 -0.008

AlHSO42+ 9.493e-17 8.844e-17 -16.023 -16.053 -0.031

FeSO4+ 1.450e-18 1.425e-18 -17.839 -17.846 -0.008

Fe(SO4)2- 3.787e-22 3.721e-22 -21.422 -21.429 -0.008

FeHSO42+ 5.307e-24 4.944e-24 -23.275 -23.306 -0.031

Si 2.791e-04

H4SiO4 2.791e-04 2.791e-04 -3.554 -3.554 0.000

H3SiO4- 2.717e-08 2.669e-08 -7.566 -7.574 -0.008

H2SiO4-2 1.082e-15 1.008e-15 -14.966 -14.997 -0.031

Sr 1.141e-08

Sr2+ 1.138e-08 1.061e-08 -7.944 -7.974 -0.031

SrSO4 2.371e-11 2.371e-11 -10.625 -10.625 0.000

SrHCO3+ 1.084e-11 1.065e-11 -10.965 -10.973 -0.008

SrCO3 1.487e-14 1.487e-14 -13.828 -13.828 0.000

SrOH+ 4.297e-16 4.222e-16 -15.367 -15.374 -0.008

-----------------------Saturation indices-------------- BLOC 3.4------

Phase SI log IAP log KT

Al(OH)3(a) -1.11 10.02 11.13 Al(OH)3

Albite -4.54 -22.87 -18.33 NaAlSi3O8

Alunite -1.63 -2.41 -0.77 KAl3(SO4)2(OH)6

Anhydrite -4.92 -9.27 -4.34 CaSO4

Anorthite -6.17 -26.03 -19.86 CaAl2Si2O8

Aragonite -4.64 -12.95 -8.31 CaCO3

Ca-Montmorillonite 3.24 -42.52 -45.76 Ca0.165Al2.33Si3.67O10(OH)2

Calcite -4.49 -12.95 -8.45 CaCO3

Celestite -6.27 -12.89 -6.62 SrSO4

CH4(g) -54.86 -57.66 -2.80 CH4

Chalcedony 0.06 -3.55 -3.61 SiO2

Chlorite(14A) -25.55 44.73 70.27 Mg5Al2Si3O10(OH)8

Chrysotile -18.73 14.10 32.83 Mg3Si2O5(OH)4

CO2(g) -2.21 -3.62 -1.41 CO2

Dolomite -9.28 -26.25 -16.97 CaMg(CO3)2

Fe(OH)3(a) -4.14 0.75 4.89 Fe(OH)3

Gibbsite 1.62 10.02 8.40 Al(OH)3

Goethite 1.57 0.75 -0.82 FeOOH

Gypsum -4.68 -9.27 -4.58 CaSO4:2H2O

H2(g) -19.73 24.10 43.83 H2

H2O(g) -1.64 -0.00 1.64 H2O

Halite -11.06 -9.49 1.57 NaCl

Hausmannite -30.49 31.80 62.29 Mn3O4

Hematite 5.12 1.49 -3.62 Fe2O3

Illite 0.53 -40.42 -40.95 K0.6Mg0.25Al2.3Si3.5O10(OH)2

Jarosite-K -21.41 -30.22 -8.82 KFe3(SO4)2(OH)6

K-feldspar -1.96 -22.91 -20.96 KAlSi3O8

K-mica 6.87 20.32 13.45 KAl3Si3O10(OH)2

Kaolinite 5.05 12.93 7.88 Al2Si2O5(OH)4

Manganite -11.44 13.90 25.34 MnOOH

Melanterite -10.42 -12.70 -2.27 FeSO4:7H2O

O2(g) -45.35 -48.21 -2.85 O2

Pyrochroite -11.19 4.01 15.20 Mn(OH)2

Pyrolusite -18.41 23.79 42.19 MnO2:H2O

Quartz 0.48 -3.55 -4.04 SiO2

Rhodochrosite -5.26 -16.37 -11.11 MnCO3

Sepiolite -12.42 3.48 15.89 Mg2Si3O7.5OH:3H2O

Sepiolite(d) -15.18 3.48 18.66 Mg2Si3O7.5OH:3H2O

Siderite -5.52 -16.38 -10.86 FeCO3

SiO2(a) -0.80 -3.55 -2.75 SiO2

Strontianite -7.30 -16.57 -9.27 SrCO3

Talc -14.99 6.99 21.98 Mg3Si4O10(OH)2

-----------------------------------------

Beginning of batch-reaction calculations. (BLOC 4)

-----------------------------------------

Reaction step 1.

Using solution 1.

Using pure phase assemblage 1.

---------------------Phase assemblage--------------------- (BLOC4.1)---

Moles in assemblage

Phase SI log IAP log KT Initial Final Delta

Al(OH)3(a) -2.16 8.97 11.13 1.000e+01 1.000e+01 2.674e-04

Albite -1.86 -20.19 -18.33 1.000e+01 1.000e+01 -2.667e-04

Calcite -0.53 -8.98 -8.45 1.000e+01 9.998e+00 -1.578e-03

CO2(g) -1.04 -2.45 -1.41 1.000e+01 9.994e+00 -6.240e-03

Dolomite -1.58 -18.55 -16.97 1.000e+01 9.999e+00 -5.376e-04

-----------------------Solution composition--------------(BLOC4.2) --

Elements Output(Moles) Pr 15(Moles)

Al3+ 3.739e-08 3.708e-08

B3+ 2.035e-05 9.256e-08

C4+ 9.215e-03 9.276e-03

Ca2+ 2.164e-03 2.203e-03

Cl- 2.765e-05 9.314e-05

Fe2+ 1.791e-08 1.792e-08

K+ 1.100e-05 2.303e-05

Mg2+ 5.586e-04 5.544e-04

Mn2+ 1.820e-08 1.821e-08

N5+ 2.306e-05 1.055e-04

Na+ 2.789e-04 4.139e-04

S3+ (6) 1.322e-05 3.281e-05

Si4+ 1.079e-03 9.512e-04

Sr2+ 1.141e-08 2.741e-06

--------------Description of solution-------------- (BLOC4.3) -------

pH = 6.532 Charge balance

pe = 13.188 Adjusted to redox equilibrium

Activity of water = 1.000

Ionic strength = 8.219e-03

Mass of water (kg) = 9.999e-01

Total alkalinity (eq/kg) = 5.651e-03

Total CO2 (mol/kg) = 9.215e-03

Temperature (deg C) = 20.000

Electrical balance (eq) = 6.611e-06

Percent error (Cat-|An|)/(Cat+|An|) = 0.06

Iterations = 19

Total H = 1.110129e+02

Total O = 5.553001e+01

-------------------Distribution of species---------------- (BLOC4.4) ----

Log Log Log

Species Molality Activity Molality Activity Gamma

H+ 3.193e-07 2.938e-07 -6.496 -6.532 -0.036

OH- 2.542e-08 2.310e-08 -7.595 -7.636 -0.041

H2O 5.551e+01 9.998e-01 1.744 -0.000 0.000

Al 3.739e-08

Al(OH)4- 2.233e-08 2.033e-08 -7.651 -7.692 -0.041

Al(OH)2+ 1.080e-08 9.833e-09 -7.967 -8.007 -0.041

Al(OH)3 3.363e-09 3.370e-09 -8.473 -8.472 0.001

Al(OH)+2 8.412e-10 5.780e-10 -9.075 -9.238 -0.163

Al+3 5.024e-11 2.376e-11 -10.299 -10.624 -0.325

AlSO4+ 5.689e-13 5.179e-13 -12.245 -12.286 -0.041

Al(SO4)2- 1.294e-16 1.178e-16 -15.888 -15.929 -0.041

Al(HSO4)2+ 1.885e-20 1.295e-20 -19.725 -19.888 -0.163

B 2.035e-05

H3BO3 2.031e-05 2.035e-05 -4.692 -4.691 0.001

H2BO3- 3.990e-08 3.633e-08 -7.399 -7.440 -0.041

C(-4) 0.000e+00

CH4 0.000e+00 0.000e+00 -135.128 -135.127 0.001

C4+(4) 9.215e-03

HCO3- 5.528e-03 5.048e-03 -2.257 -2.297 -0.039

CO2 3.567e-03 3.574e-03 -2.448 -2.447 0.001

Ca(HCO3)+ 9.305e-05 8.497e-05 -4.031 -4.071 -0.039

Mg(HCO3)+ 2.373e-05 2.161e-05 -4.625 -4.665 -0.041

CaCO3 1.591e-06 1.594e-06 -5.798 -5.798 0.001

CO32- 1.041e-06 7.235e-07 -5.983 -6.141 -0.158

NaHCO3 7.182e-07 7.19e-07 -6.144 -6.143 0.001

MgCO3 2.381e-07 2.385e-07 -6.623 -6.622 0.001

MnHCO3+ 4.536e-09 4.129e-09 -8.343 -8.384 -0.041

NaCO3- 2.903e-09 2.643e-09 -8.537 -8.578 -0.041

SrHCO3+ 5.387e-10 4.919e-10 -9.269 -9.308 -0.039

MnCO3 5.265e-10 5.275e-10 -9.279 -9.278 0.001

SrCO3 3.007e-12 3.012e-12 -11.522 -11.521 0.001

FeHCO3+ 4.060e-16 3.696e-16 -15.391 -15.432 -0.041

FeCO3 1.269e-17 1.271e-17 -16.897 -16.896 0.001

Ca 2.164e-03

Ca2+ 2.067e-03 1.436e-03 -2.685 -2.843 -0.158

CaHCO3+ 9.305e-05 8.497e-05 -4.031 -4.071 -0.039

CaSO4 2.009e-06 2.012e-06 -5.697 -5.696 0.001

CaCO3 1.591e-06 1.594e-06 -5.798 -5.798 0.001

CaOH+ 8.909e-10 8.111e-10 -9.050 -9.091 -0.041

CaHSO4+ 3.585e-12 3.264e-12 -11.445 -11.486 -0.041

Cl 2.765e-05

Cl- 2.765e-05 2.513e-05 -4.558 -4.600 -0.041

MnCl+ 1.032e-12 9.399e-13 -11.986 -12.027 -0.041

MnCl2 1.029e-17 1.031e-17 -16.987 -16.987 0.001

FeCl+2 7.667e-19 5.268e-19 -18.115 -18.278 -0.163

FeCl+ 2.791e-20 2.541e-20 -19.554 -19.595 -0.041

MnCl3- 7.841e-23 7.139e-23 -22.106 -22.146 -0.041

FeCl2+ 7.633e-23 6.949e-23 -22.117 -22.158 -0.041

FeCl3 1.743e-28 1.747e-28 -27.759 -27.758 0.001

Fe(2) 1.468e-15

Fe2+ 1.047e-15 7.323e-16 -14.980 -15.135 -0.155

FeHCO3+ 4.060e-16 3.696e-16 -15.391 -15.432 -0.041

FeCO3 1.269e-17 1.271e-17 -16.897 -16.896 0.001

FeSO4 8.721e-19 8.737e-19 -18.059 -18.059 0.001

FeOH+ 5.919e-19 5.389e-19 -18.228 -18.269 -0.041

FeCl+ 2.791e-20 2.541e-20 -19.554 -19.595 -0.041

FeHSO4+ 1.828e-24 1.664e-24 -23.738 -23.779 -0.041

Fe(HS)2 0.000e+00 0.000e+00 -276.226 -276.225 0.001

Fe(HS)3- 0.000e+00 0.000e+00 -409.167 -409.208 -0.041

Fe(3) 1.791e-08

Fe(OH)2+ 1.355e-08 1.234e-08 -7.868 -7.909 -0.041

Fe(OH)3 4.325e-09 4.333e-09 -8.364 -8.363 0.001

Fe(OH)2+ 1.933e-11 1.328e-11 -10.714 -10.877 -0.163

Fe(OH)4- 1.204e-11 1.096e-11 -10.919 -10.960 -0.041

Fe3+ 1.724e-15 8.154e-16 -14.763 -15.089 -0.325

FeSO4+ 6.461e-17 5.883e-17 -16.190 -16.230 -0.041

FeCl2+ 7.667e-19 5.268e-19 -18.115 -18.278 -0.163

Fe2(OH)24+ 2.627e-20 5.857e-21 -19.581 -20.232 -0.652

Fe(SO4)2- 1.020e-20 9.290e-21 -19.991 -20.032 -0.041

FeCl2+ 7.633e-23 6.949e-23 -22.117 -22.158 -0.041

FeHSO42+ 6.775e-23 4.655e-23 -22.169 -22.332 -0.163

Fe3(OH)45+ 2.519e-25 2.414e-26 -24.599 -25.617 -1.018

FeCl3 1.743e-28 1.747e-28 -27.759 -27.758 0.001

H(0) 0.000e+00

H2 0.000e+00 0.000e+00 -42.585 -42.584 0.001

K 1.100e-05

K+ 1.100e-05 9.999e-06 -4.959 -5.000 -0.041

KSO4- 5.200e-10 4.734e-10 -9.284 -9.325 -0.041

KOH 1.177e-13 1.180e-13 -12.929 -12.928 0.001

Mg 5.586e-04

Mg2+ 5.341e-04 3.731e-04 -3.272 -3.428 -0.156

MgHCO3+ 2.373e-05 2.161e-05 -4.625 -4.665 -0.041

MgSO4 5.639e-07 5.650e-07 -6.249 -6.248 0.001

MgCO3 2.381e-07 2.385e-07 -6.623 -6.622 0.001

MgOH+ 3.199e-09 2.912e-09 -8.495 -8.536 -0.041

Mn(2) 1.820e-08

Mn2+ 1.313e-08 9.179e-09 -7.882 -8.037 -0.155

MnHCO3+ 4.536e-09 4.129e-09 -8.343 -8.384 -0.041

MnCO3 5.265e-10 5.275e-10 -9.279 -9.278 0.001

MnSO4 1.089e-11 1.091e-11 -10.963 -10.962 0.001

MnCl+ 1.032e-12 9.399e-13 -11.986 -12.027 -0.041

MnOH+ 5.826e-13 5.304e-13 -12.235 -12.275 -0.041

Mn(NO3)2 1.616e-17 1.620e-17 -16.791 -16.791 0.001

MnCl2 1.029e-17 1.031e-17 -16.987 -16.987 0.001

MnCl3- 7.841e-23 7.139e-23 -22.106 -22.146 -0.041

Mn(3) 4.838e-21

Mn3+ 4.838e-21 2.080e-21 -20.315 -20.682 -0.367

N(0) 4.616e-09

N2 2.308e-09 2.312e-09 -8.637 -8.636 0.001

N(3) 1.098e-15

NO2- 1.098e-15 9.970e-16 -14.959 -15.001 -0.042

N(5) 2.306e-05

NO3- 2.306e-05 2.093e-05 -4.637 -4.679 -0.042

Mn(NO3)2 1.616e-17 1.620e-17 -16.791 -16.791 0.001

Na 2.789e-04

Na+ 2.782e-04 2.535e-04 -3.556 -3.596 -0.040

NaHCO3 7.182e-07 7.196e-07 -6.144 -6.143 0.001

NaSO4- 9.949e-09 9.059e-09 -8.002 -8.043 -0.041

NaCO3- 2.903e-09 2.643e-09 -8.537 -8.578 -0.041

NaOH 5.688e-12 5.699e-12 -11.245 -11.244 0.001

O(0) 2.591e-09

O2 1.296e-09 1.298e-09 -8.888 -8.887 0.001

S(-2) 0.000e+00

H2S 0.000e+00 0.000e+00 -134.543 -134.542 0.001

HS- 0.000e+00 0.000e+00 -134.978 -135.020 -0.041

S2- 0.000e+00 0.000e+00 -141.398 -141.557 -0.159

Fe(HS)2 0.000e+00 0.000e+00 -276.226 -276.225 0.001

Fe(HS)3- 0.000e+00 0.000e+00 -409.167 -409.208 -0.041

S(6) 1.322e-05

SO42- 1.064e-05 7.363e-06 -4.973 -5.133 -0.160

CaSO4 2.009e-06 2.012e-06 -5.697 -5.696 0.001

MgSO4 5.639e-07 5.650e-07 -6.249 -6.248 0.001

NaSO4- 9.949e-09 9.059e-09 -8.002 -8.043 -0.041

KSO4- 5.200e-10 4.734e-10 -9.284 -9.325 -0.041

HSO4- 2.076e-10 1.890e-10 -9.683 -9.723 -0.041

MnSO4 1.089e-11 1.091e-11 -10.963 -10.962 0.001

SrSO4 1.020e-11 1.022e-11 -10.991 -10.990 0.001

CaHSO4+ 3.585e-12 3.264e-12 -11.445 -11.486 -0.041

AlSO4+ 5.689e-13 5.179e-13 -12.245 -12.286 -0.041

Al(SO4)2- 1.294e-16 1.178e-16 -15.888 -15.929 -0.041

FeSO4+ 6.461e-17 5.883e-17 -16.190 -16.230 -0.041

FeSO4 8.721e-19 8.737e-19 -18.059 -18.059 0.001

AlHSO4+2 1.885e-20 1.295e-20 -19.725 -19.888 -0.163

Fe(SO4)2- 1.020e-20 9.290e-21 -19.991 -20.032 -0.041

FeHSO4+2 6.775e-23 4.655e-23 -22.169 -22.332 -0.163

FeHSO4+ 1.828e-24 1.664e-24 -23.738 -23.779 -0.041

Si 1.079e-03

H4SiO4 1.079e-03 1.081e-03 -2.967 -2.966 0.001

H3SiO4- 4.978e-07 4.532e-07 -6.303 -6.344 -0.041

H2SiO42- 1.092e-13 7.502e-14 -12.962 -13.125 -0.163

Sr 1.141e-08

Sr2+ 1.086e-08 7.560e-09 -7.964 -8.121 -0.157

SrHCO3+ 5.387e-10 4.919e-10 -9.269 -9.308 -0.039

SrSO4 1.020e-11 1.022e-11 -10.991 -10.990 0.001

SrCO3 3.007e-12 3.012e-12 -11.522 -11.521 0.001

SrOH+ 1.446e-15 1.319e-15 -14.840 -14.880 -0.040

--------------------Saturation indices--------------(BLOC4.5) --------

Phase SI log IAP log KT

Al(OH)3(a) -2.16 8.97 11.13 Al(OH)3

Albite -1.86 -20.19 -18.33 NaAlSi3O8

Alunite -7.18 -7.95 -0.77 KAl3(SO4)2(OH)6

Anhydrite -3.63 -7.98 -4.34 CaSO4

Anorthite -4.30 -24.16 -19.86 CaAl2Si2O8

Aragonite -0.68 -8.98 -8.31 CaCO3

Ca-Montmorillonite 3.42 -42.34 -45.76 Ca0.165Al2.33Si3.67O10(OH)2

Calcite -0.53 -8.98 -8.45 CaCO3

Celestite -6.63 -13.25 -6.62 SrSO4

CH4(g) -132.33 -135.13 -2.80 CH4

Chalcedony 0.64 -2.97 -3.61 SiO2

Chlorite(14A) -13.05 57.22 70.27 Mg5Al2Si3O10(OH)8

Chrysotile -9.86 22.97 32.83 Mg3Si2O5(OH)4

CO2(g) -1.04 -2.45 -1.41 CO2

Dolomite -1.58 -18.55 -16.97 CaMg(CO3)2

Fe(OH)3(a) -0.38 4.51 4.89 Fe(OH)3

FeS(ppt) -139.71 -143.62 -3.92 FeS

Gibbsite 0.58 8.97 8.40 Al(OH)3

Goethite 5.33 4.51 -0.82 FeOOH

Gypsum -3.39 -7.98 -4.58 CaSO4:2H2O

H2(g) -39.39 4.44 43.83 H2

H2O(g) -1.64 -0.00 1.64 H2O

H2S(g) -133.55 -141.55 -8.00 H2S

Halite -9.77 -8.20 1.57 NaCl

Hausmannite -7.77 54.52 62.29 Mn3O4

Hematite 12.64 9.01 -3.62 Fe2O3

Illite 1.18 -39.77 -40.95 K0.6Mg0.25Al2.3Si3.5O10(OH)2

Jarosite-K -12.52 -21.34 -8.82 KFe3(SO4)2(OH)6

K-feldspar -0.63 -21.59 -20.96 KAlSi3O8

K-mica 6.10 19.55 13.45 KAl3Si3O10(OH)2

Kaolinite 4.13 12.01 7.88 Al2Si2O5(OH)4

Mackinawite -138.98 -143.62 -4.65 FeS

Manganite -0.59 24.75 25.34 MnOOH

Melanterite -18.00 -20.27 -2.27 FeSO4:7H2O

N2(g) -5.49 -8.64 -3.14 N2

O2(g) -6.03 -8.89 -2.85 O2

Pyrite -227.12 -245.74 -18.62 FeS2

Pyrochroite -10.17 5.03 15.20 Mn(OH)2

Pyrolusite 2.27 44.47 42.19 MnO2:H2O

Quartz 1.07 -2.97 -4.04 SiO2

Rhodochrosite -3.07 -14.18 -11.11 MnCO3

Sepiolite -5.52 10.37 15.89 Mg2Si3O7.5OH:3H2O

Sepiolite(d) -8.29 10.37 18.66 Mg2Si3O7.5OH:3H2O

Siderite -10.42 -21.28 -10.86 FeCO3

SiO2(a) -0.21 -2.97 -2.75 SiO2

Strontianite -4.99 -14.26 -9.27 SrCO3

Sulfur -100.10 -95.10 5.00 S

Talc -4.94 17.04 21.98 Mg3Si4O10(OH)2

------------------

End of simulation.

Reading input data for simulation 2.

End of run.

No memory leaks

----------

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