Research Article Multivariate Analysis of Confined...

Research ArticleMultivariate Analysis of Confined Groundwater Hydrochemistryof a Long-Exploited Sedimentary Basin in Northwest China

Xuedi Zhang12 Hui Qian12 Hao Wu12 Jie Chen12 and Liang Qiao12

1School of Environmental Science and Engineering Changrsquoan University No 126 Yanta Road Xirsquoan Shaanxi 710054 China2Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas Ministry of Education No 126 Yanta RoadXirsquoan Shaanxi 710054 China

Correspondence should be addressed to Xuedi Zhang zhangxuedi2007163com

Received 15 September 2015 Revised 18 January 2016 Accepted 8 February 2016

Academic Editor Samuel B Dampare

Copyright copy 2016 Xuedi Zhang et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A series of environmental and geological problems have been caused by overexploitation of confined aquifers (ie deepgroundwater) in the Yinchuan region northwest China Accordingly the characteristics of confined water were analyzedand collected from 33 sampling wells in spring of 2011 to determine the factors that influenced the composition andevolution of confined water using principal component analysis (PCA) correlation analysis groundwater evolution and mineraldissolutionprecipitation analysis PCA showed that the hydrochemistry of confined water is controlled mainly by the dissolutionof minerals mixing between the confined aquifer and polluted phreatic water and effects of ion exchange in the study area Thefollowing management actions recommended were essential in order to enable the sustainable exploitation of confined water (1)gradually decreasing the amount of groundwater pumped from confined aquifer in the central part of the depression cone (2)upgrading the quality of phreatic water and (3) increasing artificial recharge of the groundwater system by flood waters in theHelan leaning pluvial plain

1 Introduction

Groundwater resources which are found in the loose sed-imentary aquifers often have good quality are not easyto be polluted are widely distributed have large amountof exploitation and have little variability among years [1]They therefore serve as major sources of freshwater in manycountries around the world supporting so many needs foragriculture industry andmunicipal drinking [1 2] Howeverwith the soaring water demands for increasing industriali-sation and urbanisation the groundwater exploitation risessharply forming depression cones in some areas in the worldleakage recharge from other aquifers then occurs which isinevitable providing an alternative source to compensate theincreasing groundwater withdrawal [1 3 4]

However the groundwater hydrochemistry of sedimentaquifers can be affected by multiple natural factors suchas chemical reactions between groundwater and sedimentsbiochemical reactions and surface water-groundwater inter-actions along with agriculture irrigation [4 5] and other

human activities [6ndash11] Whether treated or not industrialand municipal wastewaters are constant pollution sourcesthat will pollute phreatic aquifer and then influence hydro-chemistry of confined water [4 5 9 11] And this may beespecially serious in areas where groundwater was concen-trated and exploited from deep aquifers such as the studyarea [4] Diverse phenomena such as mix pumping fromseveral aquifers with different quality heating and coolingwater by ground-source heat pumps underground storageof waste injecting industrial effluents into aquifers and theartificial recharge of aquifers (eg protecting depressioncone in cities by groundwater injection well) [12] can beconsidered as point sources of pollution for deep aquifersAdditionally shallow aquifers may be polluted by nonpointsources such as the infiltration of chemical fertilizers andpesticides used in agriculture via leaching into irrigationwater [4 5] and then leakage recharge deep aquifers asnonpoint sources in depression cones [3 4] Such pollutionsources and groundwater exploitation from deep aquiferswill exert great influence over groundwater resources of

Hindawi Publishing CorporationJournal of ChemistryVolume 2016 Article ID 3812125 15 pageshttpdxdoiorg10115520163812125

2 Journal of Chemistry

deep aquifers by profoundly altering their hydrochemistrycausing many problems such as the deterioration of wetlands[13] land subsidence [14] seawater intrusion [15 16] adecline in groundwater levels and building damage [14]Once a sediment aquifer deteriorated the time and cost ofrestoration to its original condition may be excessive [15]

As studied in our former paper published in ldquoWaterrdquo[4] confined water of the Yinchuan region of northwestChina existing in Quaternary loose sediment aquifers is themain water source of industrial use and municipal drinking[4] As the groundwater quality of phreatic aquifers hasbeen deteriorated in general [4] so industrial and drinkingneeds in Yinchuan city seek for confined water since 1970sAnd sim87 times 107m3a groundwater has been exploited ina concentrated manner from the confined aquifers by 212wells forming a depression cone in the vicinity of NingxiaUniversity [4]

Given the confined aquiferrsquos roof depth of 25ndash60m anda relatively continuous clay layer that exists between theconfined aquifer and phreatic aquifer across thewhole regionthe recharge of the confined aquifer therefore occurs mainlyvia groundwater runoff from boundaries of the study areaand leakage recharge from phreatic aquifer in the depressioncone [17] So the confined water is not easily polluted bythe external environment under typical conditionsHoweverwidespread contamination has lowered the quality of phreaticwater in irrigation farmland areas (just matching the studyarea) by domestic sewage (more than 60 times 107m3 in 2011)industrial effluent (about 10 times 108m3 in 2011) and chemicalfertilizers in point sources and nonpoint sources [4] Themain causes of confined aquifers contamination are aquiferdeterioration due to leakage recharge from phreatic aquifersin the depression cone and mixed pumping from severalaquifers in some irrigation wells (including polluted phreaticaquifer and confined aquifer)

Along with the aforementioned factors increased pump-ing of groundwater from the confined aquifer adds a fun-damental pressure to groundwater quality and managementOver time artificial perturbations of pumping (ie fluctu-ations in the rate and frequency) have greatly influencedthe natural hydrochemical patterns of confined water inthe Yinchuan region Human interventions have also causedcomplicated spatial-temporal changes in the quantity andquality of confinedwater in the depression cone giving rise toa unique artificial-natural ecosystem These pressures makethe dynamics of confined water hydrochemistry in the regionrelatively more complex

As the hydrochemistry and influence factors of phreaticwater have been discussed [4] and from the close connectionof phreatic water and confined water in the study area alongwith the given complexity numerous studies can providea comprehensive understanding of confined water hydrol-ogy especially regarding the interactions between confinedaquifers and phreatic aquifers For instance multivariatestatistical techniques such as principal component analysis(PCA) have been used widely in hydrogeological studiesto reduce the complexity of large-scale data sets and thusidentify relationships among numerous factors Some studieshave done so to analyze temporal changes in surface or

groundwater characteristics [18ndash22] while others have usedPCA to analyze the relationship between a pollutant andother physicochemical parameters [23] or to describe thecharacteristics of a given aquatic system [24ndash26]

So in this context in order to determine the compositionand formation of confined water and the effect analysis ofphreatic water on it the hydrogeological processes involvedin recharge runoff and discharge of sedimentary aquifer ofthe Yinchuan region have been analyzed by multifactorialstatistical analysis and serve as a simple example to providesuggestion for the status change evolution and protectionof groundwater ecological environment under groundwaterconcentrated exploitation in other aridsemiarid area Suchan approach can provide a means to explain the currentstatus of groundwater variability to determine the factorsthat influence the quality of confined water in Yinchuanand then to develop sound groundwatermanagement optionsto preserve the quantity and quality of water resourcesand avoid the undesirable impact of phreatic water on theconfined aquifer Our specific objectives were to (1) calculatesaturation indices to analyze the dissolutionprecipitation ofminerals (2) assess the chemical characteristics of confinedwater in order to identify factors that affect the regionrsquosconfined water chemistry (3) use PCA to identify the maindrivers of confined water hydrochemistry and (4) use cor-relation analysis to identify several relevant hydrochemicalrelationships

2 Study Area

21 Location The study area is located in the middle of theYinchuan plain northwest China It measures 31sim44 kmwidefrom the front of Helan Mountain in the west to the YellowRiverrsquos western bank in the east and 38 km long from southto north with a total area of 1555 km2 (Figure 1)

The Yinchuan region has an arid to semiarid climatewithin the north temperature zone with long winters shortsummers low rainfall frequent droughts ample sunshinehigh wind and evaporation and dramatic temperaturechanges According to monitoring data from 1951 to 2010the mean annual precipitation is 1919mm with 70 of itconcentrated from July to September and the average annualevaporation is 15828mm more than 8 times the amount ofprecipitation [27]

22 Hydrogeology The study arearsquos elevation is in the rangeof 1100sim1150m above mean sea level and is higher in the westand lower in the east Landforms show a zonal distributionsloping from the leaning pluvial plain at the foot of HelanMountain in the west to the pluvial-alluvial plain of theYellow River and alluvial-lacustrine plain and alluvial flat inthe east (Figure 1)

The Yinchuan plain was formed by deposition of riverlake and flood sediments over a Cenozoic fault basin It isa graben basin based on evolution of the Helan tectonicbelt that experienced numerous rising and sinking processesbetween theMesoproterozoic and Cenozoic eras [17 28]Thepore water aquifers can be divided into two main aquifer

Journal of Chemistry 3

Alluvial flatAlluvial-lacustrine plainPluvial-alluvial plainLeaning pluvial plain

Discharge ditchIrrigation canalSites

Study area

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

18580000 18590000 18600000 18610000 18620000 18630000

4250000

4260000

4270000

4280000

Pluvial-alluvial plain Alluvia

l flat

Alluvial-lacustrine plain

Pluvial-alluvial plain

Leaning pluvial plain

Alluvial flat

Yello

w Ri

ver

(km)0 5 10

A

Ningxia University

EWN

S

China

A998400

Figure 1 Location of the study area and landforms in Yinchuan Ningxia Province China according to [4]

Single phreaticwater zone

Multilayered structuremdashphreatic aquifer

Multilayered structuremdashthe first confined aquifer

Multilayered structuremdashthe second confined aquifer

Multilayered structuremdashthe first aquitards

Multilayered structuremdashthe second aquitards

The Yellow Rivereast

Figure 2 The conceptual scheme of hydrogeological cross section from A to A1015840

systems a single phreatic water zone and an area with amultilayered structure that is the study area [4] (Figure 2)characterized by three aquifer layers within a depth of 250mmoving down from the surface they are phreatic aquiferupper confined aquifer and lower confined aquifer and theseaquifers are separated by nearly continuous 3sim10m-thicklow permeability aquitards [17]

The hydrogeological research focuses on the relationshipbetween the confined and phreatic aquifers The distributionof groundwater levels of the confined water is consistent withtopography and groundwater flows mainly from west to eastin nature (Figure 3) but the specific runoff directions andconditions vary somewhat across the region

In order to supply the consumption of industrial anddrinking water in Yinchuan city a long-term concentratedexploitation of groundwater (212 wells) from the confined

aquifer has been implemented at the rate of 87 times 107m3afor more than 50 years [4] and a depression cone has formedin the area bounded by Luhuatai and Gaomiao in the northFengying village and Pingjibu in the south the West MainCanal in the west and Daxin town in the east with an area of41237 km2 in 2011 So the lateral direction of groundwaterflow changes greatly at the center of the depression coneand the hydraulic gradient increases significantly a range of006ndash51 As the groundwater level difference phreaticwater recharges the confined water in the vertical directionin a large amount about 91 times 107m3a while confined watersupplies the phreatic aquifer in other areas in very smallamount [4]

The roof depth of the confined aquifer is sim25ndash60m witha relatively continuous clay layer between the confined andphreatic aquifers in the study area with a typical thickness


1096

1102

1102

1102

110811

08

1108

1114

1114

1120

1120

1126

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

4250000

4260000

4270000

4280000

Groundwater levelSampling well Study area

EWN

S

Flow direction

(km)0 5 10

Figure 3 Hydrogeological map of confined aquifer and sampling wells in the study area (m)

of 3ndash10m (maximum 50m) that decreases from west to eastRecharge of the confined aquifer therefore occurs mainly vialeakage recharge by the phreatic aquifer in vertical directionand also runoff from the single phreatic water zone at theboundary of confined aquifer with the single phreatic waterzone in west (sim36 times 107m3a) (Figure 3) accounting for sim24 of the total recharge

The main pollution source of confined water in the studyarea is the polluted phreatic aquifer which has itself beencontaminated seriously by industrial waste sewage pesti-cides and fertilizers infiltrating into groundwater [4] Thesesources can be classified according to the three basic formsof groundwater pollution point sources nonpoint sourcesand linear sources Point source pollution refers mainly toindustrial wastewater from factories such as the Yinchuanchemical fertilizer plant and Helan paper mill Another pointsource is agriculture such as sewage ponds garbage dumpsseptic tanks and fish ponds that use fertilizers Key linearpollution sources are drainage ditches accepting domesticsewage from families and industrial wastewater from millsThe important ditches in the region are the four-two mainditch the 2nd and 4th drainage ditches and the three-one branch ditch Discharge of industrial effluent (about10 times 108m3 in 2011) and domestic sewage (more than 60times 107m3 in 2011) through these channels flow into theYellow River polluting groundwater along the seepage pathof unlined ditches in infiltrating manner Nonpoint sourcepollution refers to the chemical fertilizers and toxic pesticidesused in agriculture (about 5ndash10 gm2) which contaminated

shallow groundwater indirectly (phreatic water in the studyarea) [4]

3 Materials and Methods

31 Sampling Locations and Analytical Procedures Ground-water samples of confined aquifer were taken from 33 wells in2011 before the summer-autumn irrigation periodTheywerelabeled with a 3-character code CAB where C representsconfined water and AB is the two-digit number of the sam-pling station (Figure 3) Physicochemical parameters such aspH and temperature were measured in situ Sampling waterwas collected in precleaned 1 L plastic polyethylene bottlesafter 3 times thorough rinse of the bottle with sampling waterHandling and preservation of samples followed the standardexaminationmethods for drinking water tomaximize qualityand consistency [29] We checked those measurements bycalculating percent charge balance errors ( CBE)

CBE = sum cations minus sum anionssum cations + sum anions

times 100 (1)

where all cations and anions are expressed as milliequiva-lentsL All samples had small relative errors ( CBE) oflt plusmn5 therefore all 33 samples were used in analyses (seeSupplementary Data in Supplementary Material availableonline at httpdxdoiorg10115520163812125)

32 Multivariate Statistical Analysis Multivariate statisticaltechniques such as PCA can provide ldquounbiased methodsrdquo to


Table 1 Descriptive statistics of hydrochemistry in Yinchuan China

Parameters Confined water Phreatic water National standardCategory Minimum Maximum Mean SD CV pH 806 843 821 016 002 757 65ndash85TH 129 441 244 71 029 662 450TDS 307 799 472 162 034 889 1000Ca2+ 115 941 444 198 045 1115 mdashMg2+ 58 73 371 134 036 1070 mdashK+ 10 35 20 06 030 72 mdashNa+ 272 168 75 48 064 1470 200Clminus 199 258 67 58 087 1380 250SO4

2minus 177 175 84 45 054 2940 250HCO

3

minus 195 484 285 61 021 mdash mdashNO3

minus 00 2 01 04 346 179 20NH4

+ 00 09 01 02 352 01 020Fminus 01 07 02 01 066 13 1Units mgL (except for pH)ldquoPhreatic waterrdquo is the quality of phreatic water located in the central of the depression cone

detect associations between samples andor variables usingstandardized data [30] Such associations among physico-chemical variables based on similar magnitudes and varia-tions in chemical and physical compositions may reveal theeffects of water-rock interaction climate and human activityon groundwater quality In order to avoid misclassificationof the water quality variables due to wide differences in thedimensions of sample data we standardized measurementswith a 119911-scale transformation [18 31] this tends to increasethe influence of main factors with small variance andvice versa All mathematical and statistical analyses wereperformed using the statistical software SPSS 160 [32] Theexperimental 32 times 12matrix was analyzed using PCA and theresulting principal components (PCs) and varimax rotatedPCs (VFs) were analyzed in detail

4 Results and Discussion

41 Hydrochemical Characteristics Analysis of the 13 hydro-chemical variables of confined water in the study area is sum-marized in Table 1 The groundwater samples were weaklyalkaline with a pH range of 806ndash843 There was no signif-icant variation of major ions concentrations among sampleswith variation coefficients varying from 021 (HCO

3

minus) to087 (Clminus) For example the concentration of TDS variedfrom 307 to 799mgL (mean 472mgL) Samples with TDSlt 500mgL were mainly from the western part of the regionthe west of the Fengdeng-Yinchuan-Wangyuan band whilesamples in the central and eastern parts usually had TDS of500ndash1000mgL (Figure 4) Only one sample C31 (the Helanpaper mill) had abnormally excessive TDS for the study areaTDS gt 15 gL indicating that it was polluted by domesticsewage and industrial wastewater so it was removed fromthis research Measures of all major ions did not exceedChinarsquos acceptable limits for groundwater quality [33] exceptfor Clminus (C31 C32) and NH

4

+ (C03 C05 C30 and C31)indicating that these samples are potable TH measured as

CaCO3varied from 129 to 441mgL (mean 244mgL) and

150 to 300mgL in most areas indicating slightly hard waterGenerally the groundwater samples from the depression conecontained high HCO

3

minus and smaller concentrations of allother ions which were more abundant in other areas due tomineral dissolution and cation exchange along the paths ofgroundwater flow [34]

Piper trilinear diagrams are used to easily distinguishhydrochemical patterns among groundwater quality data [3234 35] In terms of cations most samples fell in the centralzone of the left delta-shaped region of our Piper diagram(Figure 5) suggesting that some stations had sodium-typewater while most were mixed-type For anions most sampleswere located in the left zone of the lower right delta-shapedregion indicating the dominance of bicarbonate-type waterwhile some stations had mixed-type

42 CorrelationAnalysis Thecorrelations amongwater qual-ity variables (Table 2) can reveal several relevant hydrochem-ical relationships [32] Measures of the major ions exceptfor K+ HCO

3

minus and Mg2+ were significantly and positivelycorrelated with TDS Concentrations of Clminus SO

4

2minus andNa+ were positively related with each other with correlationcoefficients (119903) ranging from0662 to 0885 and the significantat the 001 level implying there may be a common cause ofincreases in these ions Similarly concentrations of Ca2+ andMg2+ were strongly and positively correlated with TH (119903 =0825 and 0555 resp and the significant at the 001 level) ashardness is an approximate measure of Ca2+ and Mg2+ andconcentrations of Ca2+ andMg2+ were weakly and negativelycorrelated (119903 = minus0012) TH was also strongly correlated withSO4

2minus (119903 = 0562) and HCO3

minus (119903 = 0756) by significantat the 001 level (Table 2) implying that TH includes bothtemporary and permanent hardness

We found that Na+ was positively significantly correlatedwith Clminus (119903 = 0885) by significant at the 001 level indicating


Table 2 Correlation matrix of the 13 physicochemical water parameters The values are the correlation coefficients (119903)

pH TH TDS Ca2+ Mg2+ K+ Na+ Clminus SO4

2minus HCO3

minus NO3

minus NH4

+ Fminus

pH 1TH minus0277 1TDS minus0484lowastlowast 0674lowastlowast 1Ca2+ minus0372lowast 0825lowastlowast 0706lowastlowast 1Mg2+ 0058 0555lowastlowast 0153 minus0012 1K+ minus0094 0581lowastlowast 0205 0359lowast 0500lowastlowast 1Na+ minus0459lowastlowast 0259 0883lowastlowast 0461lowastlowast minus0222 minus0119 1Clminus minus0463lowastlowast 0438lowast 0873lowastlowast 0622lowastlowast minus0141 0113 0885lowastlowast 1SO4

2minusminus0474lowastlowast 0562lowastlowast 0895lowastlowast 0519lowastlowast 0231 0207 0783lowastlowast 0662lowastlowast 1

HCO3

minusminus0222 0756lowastlowast 0476lowastlowast 0482lowastlowast 0629lowastlowast 029 0141 0081 0406lowast 1

NO3

minusminus0184 minus0093 minus0196 minus0087 minus0036 0273 minus0202 minus0128 minus0163 minus0148 1

NH4

+minus0261 0063 026 0063 0019 minus0041 0286 0391lowast 0244 minus0187 0012 1

Fminus minus0114 minus0399lowast 0188 minus0093 057lowastlowast minus038lowast 0509lowastlowast 0236 0237 minus0257 minus0208 minus0013 1lowastlowastCorrelation = significant at the level 001 (2-tailed)lowastCorrelation = significant at the level 005 (2-tailed)

C30

400

400

400

400

400

500

500

500

600

600

600

700

700

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17C18

C19

C20C22

C24C25

C26C27

C29

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

Figure 4 Spatial distribution of TDS of the study area (mgL)

halite dissolution may be the major reaction influencingwater chemistry of confinedwater in the study area Howeverthis finding is not consistent with the plots in Figure 6(a)as their concentrations were below the theoretical line (Clminusversus Na+ = 1 1 expressed in mmolL) Thus the greaterincrease of Na+ can be explained by the weathering of albiteThe dissolution of albite can be expressed as follows

2NaAlSi3O8+ 2H2CO2+ 9H2O

997888rarr Al2Si2O5(OH)4+ 2Na+ + 2HCO

3

minus

+ 4H2SiO4

2minus

(2)

In addition the ratios of HCO3

minus and Ca2+ in mostsamples were larger than two (Figure 6(b)) indicating thatthe effect of calcite dissolution on water chemistry is notobvious and HCO

3

minus comes from other sources such asalbite dissolution and ion exchange The ion exchange can beexpressed as follows Ca2+ ions in solution were replaced withNa+ from the solid surface resulting in the deviation of Ca2+out of the theoretical range (Figure 6(b)) and the surplus ofNa+ (Figure 6(a)) Consider the following

Ca2+ + 2NaXlarrrarr 2Na+ + CaX2

(3)

On the contrary HCO3

minus is positively correlatedwith Mg2+ (119903 = 0629) and less correlated with Ca2+


20

40

60

80

80 60 40 20 20 40 60 80

80

60

40

20

20

40

60

80

20

40

60

80

SO42minus

HCO3minus

Ca2+

Na+ + K+

Clminus

Mg2+

Figure 5 Piper diagram of confined water drawn with AquaChem 40

(119903 = 0482) both with the significant at the 001 level(Table 2) In addition Mg2+ is weak negatively correlatedwith Ca2+ (119903 = minus0012) which suggests the possibility ofdissolution andor precipitation of calcite and dolomiteHypothetically speaking if calcite and dolomite dissolutionwere the only source of Ca2+ and Mg2+ the ratio betweenHCO3

minus and Ca2+ Mg2+ should be within the range of 1 1to 2 1 depending on the amount of CO

2involved in the

reactions [36] because

CaCO3+H+ larrrarr Ca2+ +HCO

3

minus (4)

CaCO3+H2O + CO

2larrrarr Ca2+ + 2HCO

3

minus (5)

CaMg (CO3)2+ 2H+ larrrarr Ca2+ +Mg2+ + 2HCO

3

minus (6)

CaMg (CO3)2+ 2H2O + CO

2

larrrarr Ca2+ +Mg2+ + 4HCO3

minus

(7)

It is suggested that dolomite dissolution is probably thesource of Mg2+ and Ca2+ (Figure 6(c)) since some samplesare within the hypothetical range (HCO

3

minus versus (Ca2+ +Mg2+) = 1 1 to 2 1 expressed in mmolL) and some areabove the hypothetical straight lines (HCO

3

minus versus (Ca2+ +Mg2+) = 1 1) meaning some Ca2+ or Mg2+ ions may haveresulted from other causes From comprehensive analysisof Figures 6(b) and 6(c) the superfluous ion is mainlyMg2+ coming from the dissolution of metamorphic rock(containing Mg2+) such as brucite and montmorillonite

Ca2+ is also correlated with SO4

2minus (119903 = 0592) bysignificant at the 001 level suggesting a possible effect

of gypsum dissolution on water chemistry Consider thefollowing

CaSO4sdot 2H2Olarrrarr Ca2+ + SO

4

2minus+ 2H2O (8)

However the actual ratio between Ca2+ and SO4

2minus is not1 1 Considering the dissolution of calcite andor dolomitethat would introduce Ca2+ into groundwater it is logicalto conclude that the deviation of plotted data from the 1 1line (below the hypothetical 1 1 line) was caused by theweathering of calcium-containing minerals such as calciteand dolomite Some samples fell above the hypothetical 1 1line suggesting the cation exchange between Ca2+ and Na+(Figure 6(d))

Notably the chemical reactionswithin a groundwater sys-tem are numerous and highly complex So assessment of theexact reactions taking place demands more comprehensiveanalyses of aquifer mineralogy and groundwater flow

43 Major Ion Variation along Paths of Groundwater FlowPhysiochemical parameters for sample points along flowpath can reveal changes in solutes that occur over timeand travel distance [37] The regional evolutionary trend ofthe predominant anions along the groundwater flow pathcan be summarized as follows HCO

3

minusrarr HCO

3

minus+

SO4

2minusrarr SO

4

2minus+ HCO

3

minusrarr SO

4

2minus+ Clminus rarr Clminus +

SO4

2minusrarr Clminus [34 38] As groundwater flows from the upper

to lower reaches concentrations of Ca2+ and HCO3

minus tendto decrease while those of Na+ K+ Mg2+ SO

4

2minus and Clminusincrease [35]There are two different patterns of groundwaterevolution in the study area Figure 7(a) illustrates the normalgroundwater evolution along a flow path (from C11 to C19)


C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)

Figure 6 Plots of (a) Na+ versus Clminus (b) Ca2+ against HCO3

minus (c) Ca2+ + Mg2+ against HCO3

minus and (d) Ca2+ versus SO4

2minus (mmolL)

Concentrations of Na+ K+ Mg2+ Clminus and SO4

2minus increaseddown the gradient while Ca2+ and HCO

3

minus decreased from384 to 269mgL and from 2451 to 2127mgL respectivelyresulting in the transition of hydrochemical type fromHCO

3-

MgsdotCa to HCO3-NasdotMg However the groundwater pattern

may be different if there is local recharge of the phreaticaquifer along the flow path Along the flow path from C07 toC08 Mg2+ SO

4

2minus and Clminus decreased significantly whereasNa+ K+ and Ca2+ increased considerably and HCO

3

minus

remained relatively constant (Figure 7(b)) The second pat-tern of groundwater evolution indicates that recharge waterwith relative low concentrations of dissolved Mg2+ SO

4

2minusand Clminus (due to the adsorption of continuous 3ndash10m thickaquitards composed of clay and sand clay) could be mixedwith confined water before reaching sample well C08 andion exchange takes a notable role in this evolution Also thehydrochemical type changed from HCO

3-MgsdotCa to HCO

3-

NasdotMgThe existence of two different groundwater evolutionpatterns shows that groundwater quality in the study area isinfluenced by regional groundwater flow and local recharge

44 Saturation Indices Due to the short contact time withthe aquifer minerals andor insufficient mineral sourcesgroundwater in recharge areas or those with a falling regionalflow is not usually saturated with calcite dolomite andgypsum while groundwater in discharge areas or those witha rising flow may become saturated with these minerals Thesaturation index (SI) of calcite dolomite halite and gypsumfor each sample was calculated using the following equation[39]

SI = log IAP119870 (9)

where IAP is ion activity product in a mineral dissolutionreaction while119870 is representative of the equilibriumconstantof mineral dissolution at the active temperature (this timetakes 10∘C the average temperature for the study area) TheSI of gypsum and halite varied from minus223 to minus084 and fromminus727 tominus625 respectively (Figures 8(a) and 8(b)) suggestingthat the groundwater would tend to dissolve gypsum andhalite However the SI of calcite and dolomite ranged from


Table 3 Schoeller index values of all samples

Sample number C01 C02 C03 C04 C05 C06 C07 C08CAI-I minus092 minus094 minus020 minus006 minus109 minus106 minus065 minus121CAI-II minus043 minus043 minus016 minus002 minus022 minus015 minus009 minus015Sample number C09 C10 C11 C12 C13 C14 C15 C16CAI-I minus082 minus031 minus062 minus135 minus078 minus121 minus130 minus101CAI-II minus011 minus008 minus011 minus019 minus010 minus014 minus016 minus013Sample number C17 C18 C19 C20 C21 C22 C23 C24CAI-I minus214 minus068 minus084 minus162 minus364 minus133 minus160 minus285CAI-II minus021 minus039 minus028 minus042 minus048 minus040 minus038 minus028Sample number C25 C26 C27 C28 C29 C30 C32 C33CAI-I minus358 minus078 minus074 minus080 minus044 minus100 minus001 minus051CAI-II minus039 minus016 minus021 minus016 minus012 minus031 minus002 minus009

028 to 128 and from 201 to 339 respectively indicating thatthe groundwater is in balance to be oversaturated with thecalcite and oversaturated with the dolomite (Figures 8(c) and8(d))

441 Cation Exchange Cation exchange is a process thatcommonly modifies the major ion chemistry of groundwater[40] and significantly influences the evolution of hydro-chemical compositions [41 42] It can be studied throughchloroalkaline indices proposed by Schoeller [41ndash43] TheSchoeller indices such as CAI-I and CAI-II are calculatedusing the following formulas

CAI-I =Clminus minus (Na+ + K+)

Clminus(10)

CAI-II =Clminus minus (Na+ + K+)

HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)

where all ions are expressed in meqL If the indices werenegative values this may indicate that Ca2+ and Mg2+ havebeen removed from solution and Na+ andor K+ have takentheir place Since the indices are positive the inverse reactionshave taken place All of these samples had negative Schoellerindex values (Table 3) showing that Ca2+ andMg2+ had beenremoved from solution and Na+ andor K+ had taken theirplace in all samples

45 Principal Component Analysis (PCA) Bartlettrsquos spheric-ity test confirmed that the 12 variables were not orthogonalbut rather correlated (Bartlett 1205942 = 877 66 df 119875 le 0001)This enables explanation of the variation in these hydrochem-ical data using a lower number of variables Additionallythe Kaiser-Meyer-Olkin method (KMO) showed that themeasure of sampling adequacy (MSA) was 052 indicatingthat the degree of correlation among the variables and theappropriateness of factor analysis was moderate

The variable pH varied little and was weakly correlatedwith the others (119903 = minus0484 to 0058) so it was eliminatedfrom analysis PCA considered the hydrochemical variablescommon to all 32 samples including TH TDS K+ Na+Ca2+ Mg2+ HCO

3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus

Table 4 Loadings of variables on 4 significant varifactors (VFs) ofwater quality measurements

Variable VF1 VF2 VF3 VF4TDS 097 016 minus011 007Cl 090 minus013 005 025Na 090 minus029 minus020 015SO4

085 018 minus017 012Ca 078 025 021 minus026TH 062 073 011 minus015HCO

3036 071 minus023 minus036

K 020 058 055 minus010Mg minus005 092 minus012 011F 029 minus074 minus031 minus011NO3

minus014 minus005 085 006NH4

024 001 003 092Eigenvalue 460 299 133 120 of variance explained 383 249 111 100 cumulative variance 383 632 743 843

The correlation matrix of the 12 variables (ie standardizeddata) revealed several hydrochemical relationships relevantto interpretation of the primary factors influencing currentwater chemistry in the confined water [41 42] To reducethe overlap between original variables in each PC a varimaxrotation was conducted [18] The total variance explainedby each VF their loadings and eigenvalues were shown inTable 4 Based on the principle of eigenvalues gt 1 4 VFs wereobtained accounting for 843 of the total variance in theoriginal data set (Table 4) The first two VFs explained mostof the variance at 406 and 246 respectively while VF3and VF4 explained 106 and 84

VF1was highly related to TDS Clminus Na+ SO4

2minus Ca2+ andTH indicating that these variables may be influenced by acommon cause namely mineral dissolution during ground-water flowMajor ions such as Na+ Ca2+ SO

4

2minus and Clminus areimportant components of minerals such as halite gypsumplagioclase and mirabilite With respect to the high values of


(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)

Figure 7 Major ion variations along flow paths (a) from C11 to C19 (b) from C07 to C08

solubility product Na+ Ca2+ SO4

2minus and Clminus in the confinedaquifer have dissolution tendency and the concentrations ofNa+ Ca2+ SO

4

2minus and Clminus have in turn increased Based onparticle analysis and the Quaternary sediment history of thestudy area a very thick deposition of lake and alluvial faciesfilled the Yinchuan basin including the minerals of quartzhalite gypsum plagioclase and mirabilite Therefore it isinferred that PC1 reflected the dissolution of minerals suchas halite gypsum plagioclase and mirabilite Indeed highvalues ofVF1were associatedwith the central and east parts ofthe study area the lower reaches of groundwater flow (Figures9(a) and 3)

Interestingly VF1 values were lower in the central of thedepression cone where the hydraulic gradient is relativelylarge and phreatic water recharges confined water verticallyto a great extent so the concentrations of ions there shouldbe relatively higher Considering the adsorption of lowpermeability aquitards the groundwater quality of confinedwater there is mainly affected by mineral dissolution andadsorption action resulting in better quality [4]

Loadings onVF2 showed thatMg2+ THHCO3

minus K+ andFminus were most important for VF2 representing dissolutionof minerals (eg magnesite dolomite and potash feldspar)that contain Mg2+ HCO

3

minus and K+ In addition the strongly

negative correlation of Fminus with VF2 (119903 = minus074) indicatedthe potential precipitation of minerals (fluorite) containingFminus and Ca2+ Sampling stations in the southwest (the fine-grained zone) had high VF2 scores but the scores of otherarea were relatively small This suggests that there has beenstrong dissolution of minerals with Mg2+ HCO

3

minus and Kminusin this area with mixing action with phreatic water inthe process (Figure 7(b)) The spatial pattern of VF2 scoreswas different from that of VF1 that is the distribution ofhigh VF2 scores was concentrated in the southwest wheregroundwater flows relatively slow and the dissolution ofcarbonate minerals is common (Figure 9(b)) In the centralof the depression cone considering the adsorption of lowpermeability aquitards minerals precipitation (representedin Section 44) and the ion exchange the groundwaterquality of confined water will be better [4]

VF3 was greatly influenced by NO3

minus as the mean NO3

minus

concentration of confined water in the study area is 01mgL(Table 1) and that of phreatic water is 21mgL [4] it can beinferred to the mixing action between the confined aquiferand phreatic water polluted by nitrate fertilizers and thedrainage ditch sewage used in agricultural irrigation [44]Interestingly small VF3 values were associated with thedepression cone indicating a low effect of nitrate pollution


C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)

Figure 8 Saturation indices of minerals of confined water (a) gypsum (b) halite (c) calcite and (d) dolomite

while high NO3

minus concentrations were located in the south-west (the fine-grained zone) because in the southwest areathere are some large farms so phreatic water has high NO

3

minus

concentrations and will flow into confined aquifer at the westboundary (Figure 2)Thehighest positive loading onVF4wasNH4

+ implying an effect of human activity (eg domesticsewage discharge and agricultural fertilizers) on confinedwater from the polluted phreatic water

46 The Comprehensive Analysis of the Aquifer System Ingeneral the quality of confined water in the study areawas influenced mainly by mineral dissolutionprecipitationmixing action and cation exchange compared with phreaticaquifer by strong evaporation effect mineral dissolutionprecipitation and human activities [4] Thus the pollutionrisk of confined water in the study area is mainly the leakagerecharge of polluted phreatic aquifer in the depression coneas continuous infiltration type [4] Although the confinedwater has been exploited for more than 50 years and thegroundwater quality is also very good (eg the concentrationof TDS varied from 307 to 799mgL with a mean valueof 472mgL) however the quality of confined water hasbeen decreasing actually and confined aquifers will becomecontaminated because the aquitard layers can only provide

a limited purifying effect For example for the typical sampleC08 (Ningxia University) in the central of the depressioncone the concentration of TDS is 285mgL in 1990s andthat increased to 341mgL in 2000s According to anotherresearcher in present exploitation condition the concentra-tion of Clminus in the first confined aquifer will increase clearlyin the first 80 years (since 1970s) the increase will slowbetween 80 and 150 years and the concentration then willbecome stable after 150 years where there is excessive Clminus(gt250mgL) in the vicinity of Ningcheng village (the centralof the depression cone) with an area of about 2475 km2[45] According to the principle of adsorption taking Clminusfor example the adsorption capacity of low permeabilityaquitards in the depression cone was 222mgkg in 1991 anddecreased insignificantly to 070mgkg in 2011 It is obviousthat the adsorption capacity has been reducing from 1991 to2011 and the average adsorption amount of every five yearsalso deceases from 1001 times 105 kga to 591 times 105 kga with thetotal adsorption amount of 176 times 108 kg The adsorption willtake effect for no more than 150 a in this pumping conditionwithout taking any conversation measures

In order to protect the groundwater quality in the studyarea and hence to ensure the long-term sustainable levels ofwater extraction regarding the phreatic aquifer and confined


00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)

Figure 9 Spatial distribution of sampling stations by (a) VF1 scores and (b) VF2 scores

aquifers as an entirety groundwater system we recommendthat the following management actions must therefore beundertaken (1) Close enterprise wells of confined watergradually in the central of depression cone only keepingon the drinking wells to reduce the exploitation intensity

and well density To meet demand the Xirsquoxia reservoir hasbeen constructed for these enterprises which will save thepumping amount of 36 times 107m3a for confined water (2)Do not increase the amount of confined water pumpedfrom production wells and changing the exploitation rate by


different times instead of the central one time and additionalwater source sites and groundwater mining of confinedaquifers should be planned in other places for future useSo two prospective areas of new groundwater source siteswere delineated in the vicinity of Ligang and Zhangzhentown with pumping guarantee of 80times 104m3d (3) Establishseveral artificial recharge zones in the Helan leaning pluvialplain using flood waters as the recharge water resourcesabout 55 times 107m3a for more than 52 gullies to increasethe groundwater recharge in the recharge area of confinedwater (4) Improve the quality of phreatic water in thedepression cone by sewage treatment plant and the secondthird and fourth sewage treatment plants of Yinchuan havebeen constructed with the total treatment of 20 times 105m3dwastewater covering more than 8707 km2 and about 70 times105 people in which the third sewage treatment plant wasbuilt specially for industrial effluents in the depression cone(5) Close and fill the wells mix pumping from phreaticaquifer and confined aquifers protecting confinedwater frompolluting as the phreatic aquifer has bad quality

From a management perspective and seen phreaticaquifer and confined aquifers as a whole system [4] our sta-tistical analyses will be useful for hydrological planningmdashthisapproach avoids the undesirable location of new pumpingwells in the confined aquifer at places that show hydroge-ological or hydrochemical features associated with pollutedphreatic aquifers and thus avoids and slows down furtherdeterioration of groundwater quality And this study willserve as a simple example to provide suggestion for the statuschange evolution and protection of groundwater ecologicalenvironment under groundwater concentrated exploitationin other aridsemiarid area

5 Conclusions

Confined water is an invaluable resource that supportsnumerous activities in Yinchuan region including industrialand domestic uses However its quality has been deteri-orating gradually by leakage recharge from the pollutedphreatic water Although the Yinchuan region does nothave significant limitations on the quantity of groundwa-ter resources entirety two distinct quality problems havebeen detected phreatic water has high concentrations ofmajor ions and TDS that exceed Chinarsquos acceptable limits ofgroundwater quality and polluted phreatic water rechargesconfined water largely in the depression cone which willdeteriorate confined water slowly This paper investigatedand assessed the hydrochemistry of major ions and traceconstituents in confined water using statistical methods andmineral dissolutionprecipitation analysis and the results canbe summarized as follows

(1) Thequality of confinedwater varied slightly across theYinchuan region and its composition was relativelysimple compared to that of phreatic water TDSand concentrations of major ions generally increasedalong the groundwater flow path from west to eastMeasures of all major ions do not exceed Chinarsquosacceptable limits for groundwater quality except for

Clminus and NH4

+ in scattered areas indicating theconfined water is potable

(2) The key factors affecting the evolution of groundwaterchemistry of confinedwater in the study area aremin-eral dissolution andor precipitation cation exchangeleakage recharge and human activity (eg domesticsewage discharge agricultural fertilizers and ground-water exploitation) Based on the saturation indicesthe solubility products of calcite and dolomite wereat supersaturation with a precipitation tendencyand those of gypsum and halite were not saturatedso those minerals will dissolve into confined waterBecause of the concentrated exploitation of confinedwater a depression cone has been formed in thevicinity of Ningxia University increasing leakagerecharge to confined water which will accelerate theevolution of groundwater chemistry in the confinedaquifer

(3) Multivariate analysis of confined water quality wasused to identify different sources or processes thatare influencing confined water quality as natural orhuman activities Close examination of the four mainaxes that resulted from PCA identified three keyprocesses that influence confined water quality inthe region the dissolutionprecipitation of mineralsincluding halite gypsum plagioclase mirabilite mag-nesite dolomite potash feldspar and fluorite mixingbetween the confined water and polluted phreaticwater and effects of ion exchange

(4) In order to exploit large amounts of confined waterresources over long-term while avoiding its contam-ination by polluted phreatic water and improve thequality of the whole groundwater system we recom-mend gradual close enterprise wells in the centraldepression cone along with selectively exploitingphreatic water as an alternative to meet industrialwater needs Simultaneously flood waters on theHelan leaning pluvial plain could be used to increaseartificial recharge of the groundwater system

Competing Interests

The authors declare that they have no competing interests

Acknowledgments

This research was supported by the Doctor PostgraduateTechnical Project of Changrsquoan University (2013G5290003)and the National Natural Science Foundation of China(41172212)

References

[1] R Bowen Ground Water Applied Science Publishers LondonUK 1980

[2] M E Al-Ahmadi andA A El-Fiky ldquoHydrochemical evaluationof shallow alluvial aquifer of Wadi Marwani western Saudi


Arabiardquo Journal of King Saud UniversitymdashScience vol 21 no 3pp 179ndash190 2009

[3] R Q Yuan X F Song D M Han L Zhang and S Q WangldquoUpward recharge through groundwater depression cone inpiedmont plain of North China Plainrdquo Journal of Hydrology vol500 pp 1ndash11 2013

[4] X D Zhang H Qian J Chen and L Qiao ldquoAssessment ofgroundwater chemistry and status in a heavily used semi-aridregion with multivariate statistical analysisrdquoWater vol 6 no 8pp 2212ndash2232 2014

[5] D J Qin Y P Qian L F Han ZMWang C Li and Z F ZhaoldquoAssessing impact of irrigation water on groundwater rechargeand quality in arid environment using CFCs tritium and stableisotopes in the Zhangye Basin Northwest Chinardquo Journal ofHydrology vol 405 no 1-2 pp 194ndash208 2011

[6] B Fridrich D Krcmar B Dalmacija et al ldquoImpact of wastewa-ter from pig farm lagoons on the quality of local groundwaterrdquoAgricultural Water Management vol 135 pp 40ndash53 2014

[7] S Bartelt-Hunt D D Snow T Damon-Powell and D Mies-bach ldquoOccurrence of steroid hormones and antibiotics in shal-low groundwater impacted by livestock waste control facilitiesrdquoJournal of Contaminant Hydrology vol 123 no 3-4 pp 94ndash1032011

[8] J-C Cho H B Cho and S-J Kim ldquoHeavy contamination ofa subsurface aquifer and a stream by livestock wastewater ina stock farming area Wonju Koreardquo Environmental Pollutionvol 109 no 1 pp 137ndash146 2000

[9] M Kuderna and W E H Blum ldquoN-fluxes and efficiencies onfarms in Styria Austriardquo Environmental Pollution vol 102 no1 pp 507ndash513 1998

[10] A Kunz R L R Steinmetz M A Ramme and A ColdebellaldquoEffect of storage time on swine manure solid separationefficiency by screeningrdquo Bioresource Technology vol 100 no 5pp 1815ndash1818 2009

[11] S Lee M C Maniquiz and L-H Kim ldquoCharacteristics ofcontaminants in water and sediment of a constructed wetlandtreating piggery wastewater effluentrdquo Journal of EnvironmentalSciences vol 22 no 6 pp 940ndash945 2010

[12] S-HMoon J-Y Lee B-J Lee K-H Park and Y-J Jo ldquoQualityof harvested rainwater in artificial recharge site on Jeju volcanicisland Koreardquo Journal of Hydrology vol 414-415 pp 268ndash2772012

[13] A A L Landes L Aquilina J De Ridder L Longuevergne CPage and P Goderniaux ldquoInvestigating the respective impactsof groundwater exploitation and climate change on wetlandextension over 150 yearsrdquo Journal of Hydrology vol 509 pp367ndash378 2014

[14] C-H Chen C-H Wang Y-J Hsu S-B Yu and L-C KuoldquoCorrelation between groundwater level and altitude variationsin land subsidence area of the Choshuichi Alluvial Fan TaiwanrdquoEngineering Geology vol 115 no 1-2 pp 122ndash131 2010

[15] J Bear A H D Cheng S Sorek D Ouazar and I HerreraSeawater Intrusion in Coastal AquifersmdashConcepts Methodsand Practices Kluwer Academic Publishers Dordrecht TheNetherlands 1999

[16] S Onodera M Saito M Sawano et al ldquoEffects of intensiveurbanization on the intrusion of shallow groundwater into deepgroundwater examples from Bangkok and Jakartardquo Science ofthe Total Environment vol 404 no 2-3 pp 401ndash410 2008

[17] X HWu H Qian D M Yu et al Investigation and Assessmentof Rational Allocation of Groundwater Resources in the Yinchuan

Plain Geology Publishing House Beijing China 2008 (Chi-nese)

[18] BHelena R PardoMVega E Barrado JM Fernandez andLFernandez ldquoTemporal evolution of groundwater compositionin an alluvial aquifer (Pisuerga River Spain) by principalcomponent analysisrdquoWater Research vol 34 no 3 pp 807ndash8162000

[19] K Bengraıne and T F Marhaba ldquoUsing principal componentanalysis to monitor spatial and temporal changes in waterqualityrdquo Journal of Hazardous Materials vol 100 no 1ndash3 pp175ndash179 2003

[20] M L M Jones B Reynolds S A Brittain D A Norris P MRhind and R E Jones ldquoComplex hydrological controls on wetdune slacks the importance of local variabilityrdquo Science of theTotal Environment vol 372 no 1 pp 266ndash277 2006

[21] D Valdes J-P Dupont B Laignel S Ogier T Leboulangerand B J Mahler ldquoA spatial analysis of structural controls onKarst groundwater geochemistry at a regional scalerdquo Journal ofHydrology vol 340 no 3-4 pp 244ndash255 2007

[22] F Akbal L Gurel T Bahadir I Guler G Bakan and HBuyukgungor ldquoWater and sediment quality assessment in themid-Black Sea coast of Turkey using multivariate statisticaltechniquesrdquo Environmental Earth Sciences vol 64 no 5 pp1387ndash1395 2011

[23] M A Halim R KMajumder S A Nessa K Oda Y Hiroshiroand K Jinno ldquoArsenic in shallow aquifer in the eastern regionof Bangladesh insights from principal component analysisof groundwater compositionsrdquo Environmental Monitoring andAssessment vol 161 no 1ndash4 pp 453ndash472 2010

[24] S GiammancoMOttavianiMValenza et al ldquoMajor and traceelements geochemistry in the ground waters of a volcanic areaMount Etna (Sicily Italy)rdquoWater Research vol 32 no 1 pp 19ndash30 1998

[25] M Diaz F Pedrozo C Reynolds and P Temporetti ldquoChemicalcomposition and the nitrogen-regulated trophic state of Patag-onian lakesrdquo Limnologica vol 37 no 1 pp 17ndash27 2007

[26] S E Silliman M Boukari P Crane F Azonsi and C R NealldquoObservations on elemental concentrations of groundwater incentral Beninrdquo Journal of Hydrology vol 335 no 3-4 pp 374ndash388 2007

[27] H Qian J H Wu Y H Zhou and P Y Li ldquoStable oxygenand hydrogen isotopes as indicators of lake water recharge andevaporation in the lakes of the Yinchuan Plainrdquo HydrologicalProcesses vol 28 no 10 pp 3554ndash3562 2014

[28] L Zhang and L Wang Groundwater Resources in NingxiaNingxia People Publishing House Yinchuan China 2003(Chinese)

[29] Ministry of Health of the Peoplersquos Republic of China Standardsfor Drinking Water Quality GB 5749-2006 Standards Press ofChina Beijing China 2007

[30] Q Y TangDPScopy Data Processing System Experimental DesignStatistical Analysis and Data Mining Science Press BeijingChina 2nd edition 2010 (Chinese)

[31] P Willet Similarity and Clustering in Chemical InformationSystems Research Studies Press JohnWiley amp Sons New YorkNY USA 1987

[32] J H Wu P Y Li H Qian Z Duan and X D Zhang ldquoUsingcorrelation and multivariate statistical analysis to identifyhydrogeochemical processes affecting the major ion chemistryof waters a case study in Laoheba phosphorite mine in SichuanChinardquo Arabian Journal of Geosciences vol 7 no 10 pp 3973ndash3982 2013


[33] Ministry of Geology and Mineral Resources of the PeoplersquosRepublic of China ldquoQuality standard for ground waterrdquo TechRep GBT 14848-93 Standards Press of China Beijing China1994

[34] H Qian and P Y Li ldquoHydrochemical characteristics of ground-water in Yinchuan plain and their control factorsrdquoAsian Journalof Chemistry vol 23 no 7 pp 2927ndash2938 2011

[35] M Hussain S M Ahmed and W Abderrahman ldquoClusteranalysis and quality assessment of logged water at an irrigationproject eastern Saudi Arabiardquo Journal of Environmental Man-agement vol 86 no 1 pp 297ndash307 2008

[36] P Y Li H Qian J HWu Y Q Zhang andH B Zhang ldquoMajorion chemistry of shallow groundwater in the Dongsheng Coal-field Ordos Basin Chinardquo Mine Water and the Environmentvol 32 no 3 pp 195ndash206 2013

[37] RW Lee ldquoGeochemistry of water in the Fort Union Formationof the Northern Powder River Basin Southeastern MontanardquoUSGS Water-Supply Paper 2076 US Government PrintingOffice Washington DC USA 1981

[38] I I Chebotarev ldquoMetamorphism of natural waters in the crustof weatheringmdash1rdquoGeochimica et Cosmochimica Acta vol 8 no1-2 pp 22ndash48 1955

[39] H Qian and Z Y Ma Hydrogeochemistry Geology PublishingHouse Beijing China 2005 (Chinese)

[40] J Xiao Z D Jin F Zhang and J Wang ldquoSolute geochemistryand its sources of the groundwaters in the Qinghai Lakecatchment NWChinardquo Journal of Asian Earth Sciences vol 52pp 21ndash30 2012

[41] L Pei-Yue Q Hui and W Jian-Hua ldquoApplication of set pairanalysis method based on entropy weight in groundwaterquality assessmentmdasha case study inDongsheng City NorthwestChinardquo E-Journal of Chemistry vol 8 no 2 pp 851ndash858 2011

[42] P Y Li H Qian and J H Wu ldquoHydrochemical characteristicsand evolution laws of drinking groundwater in PengyangCountyNingxiaNorthwestChinardquoE-Journal of Chemistry vol8 no 2 pp 565ndash575 2011

[43] DMarghadeD BMalpe andA B Zade ldquoMajor ion chemistryof shallow groundwater of a fast growing city of Central IndiardquoEnvironmental Monitoring and Assessment vol 184 no 4 pp2405ndash2418 2012

[44] D Ronen andMMagaritz ldquoHigh concentration of solutes at theupper part of the saturated zone (water table) of a deep aquiferunder sewage-irrigated landrdquo Journal of Hydrology vol 80 no3-4 pp 311ndash323 1985

[45] Z H Zhang Study on the groundwater pollution simulation inYinchuan Region [Masterrsquos thesis] Changrsquoan University XirsquoanChina 2014 (Chinese)

Submit your manuscripts athttpwwwhindawicom

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CatalystsJournal of


deep aquifers by profoundly altering their hydrochemistrycausing many problems such as the deterioration of wetlands[13] land subsidence [14] seawater intrusion [15 16] adecline in groundwater levels and building damage [14]Once a sediment aquifer deteriorated the time and cost ofrestoration to its original condition may be excessive [15]

As studied in our former paper published in ldquoWaterrdquo[4] confined water of the Yinchuan region of northwestChina existing in Quaternary loose sediment aquifers is themain water source of industrial use and municipal drinking[4] As the groundwater quality of phreatic aquifers hasbeen deteriorated in general [4] so industrial and drinkingneeds in Yinchuan city seek for confined water since 1970sAnd sim87 times 107m3a groundwater has been exploited ina concentrated manner from the confined aquifers by 212wells forming a depression cone in the vicinity of NingxiaUniversity [4]

Given the confined aquiferrsquos roof depth of 25ndash60m anda relatively continuous clay layer that exists between theconfined aquifer and phreatic aquifer across thewhole regionthe recharge of the confined aquifer therefore occurs mainlyvia groundwater runoff from boundaries of the study areaand leakage recharge from phreatic aquifer in the depressioncone [17] So the confined water is not easily polluted bythe external environment under typical conditionsHoweverwidespread contamination has lowered the quality of phreaticwater in irrigation farmland areas (just matching the studyarea) by domestic sewage (more than 60 times 107m3 in 2011)industrial effluent (about 10 times 108m3 in 2011) and chemicalfertilizers in point sources and nonpoint sources [4] Themain causes of confined aquifers contamination are aquiferdeterioration due to leakage recharge from phreatic aquifersin the depression cone and mixed pumping from severalaquifers in some irrigation wells (including polluted phreaticaquifer and confined aquifer)

Along with the aforementioned factors increased pump-ing of groundwater from the confined aquifer adds a fun-damental pressure to groundwater quality and managementOver time artificial perturbations of pumping (ie fluctu-ations in the rate and frequency) have greatly influencedthe natural hydrochemical patterns of confined water inthe Yinchuan region Human interventions have also causedcomplicated spatial-temporal changes in the quantity andquality of confinedwater in the depression cone giving rise toa unique artificial-natural ecosystem These pressures makethe dynamics of confined water hydrochemistry in the regionrelatively more complex

As the hydrochemistry and influence factors of phreaticwater have been discussed [4] and from the close connectionof phreatic water and confined water in the study area alongwith the given complexity numerous studies can providea comprehensive understanding of confined water hydrol-ogy especially regarding the interactions between confinedaquifers and phreatic aquifers For instance multivariatestatistical techniques such as principal component analysis(PCA) have been used widely in hydrogeological studiesto reduce the complexity of large-scale data sets and thusidentify relationships among numerous factors Some studieshave done so to analyze temporal changes in surface or

groundwater characteristics [18ndash22] while others have usedPCA to analyze the relationship between a pollutant andother physicochemical parameters [23] or to describe thecharacteristics of a given aquatic system [24ndash26]

So in this context in order to determine the compositionand formation of confined water and the effect analysis ofphreatic water on it the hydrogeological processes involvedin recharge runoff and discharge of sedimentary aquifer ofthe Yinchuan region have been analyzed by multifactorialstatistical analysis and serve as a simple example to providesuggestion for the status change evolution and protectionof groundwater ecological environment under groundwaterconcentrated exploitation in other aridsemiarid area Suchan approach can provide a means to explain the currentstatus of groundwater variability to determine the factorsthat influence the quality of confined water in Yinchuanand then to develop sound groundwatermanagement optionsto preserve the quantity and quality of water resourcesand avoid the undesirable impact of phreatic water on theconfined aquifer Our specific objectives were to (1) calculatesaturation indices to analyze the dissolutionprecipitation ofminerals (2) assess the chemical characteristics of confinedwater in order to identify factors that affect the regionrsquosconfined water chemistry (3) use PCA to identify the maindrivers of confined water hydrochemistry and (4) use cor-relation analysis to identify several relevant hydrochemicalrelationships

2 Study Area

21 Location The study area is located in the middle of theYinchuan plain northwest China It measures 31sim44 kmwidefrom the front of Helan Mountain in the west to the YellowRiverrsquos western bank in the east and 38 km long from southto north with a total area of 1555 km2 (Figure 1)

The Yinchuan region has an arid to semiarid climatewithin the north temperature zone with long winters shortsummers low rainfall frequent droughts ample sunshinehigh wind and evaporation and dramatic temperaturechanges According to monitoring data from 1951 to 2010the mean annual precipitation is 1919mm with 70 of itconcentrated from July to September and the average annualevaporation is 15828mm more than 8 times the amount ofprecipitation [27]

22 Hydrogeology The study arearsquos elevation is in the rangeof 1100sim1150m above mean sea level and is higher in the westand lower in the east Landforms show a zonal distributionsloping from the leaning pluvial plain at the foot of HelanMountain in the west to the pluvial-alluvial plain of theYellow River and alluvial-lacustrine plain and alluvial flat inthe east (Figure 1)

The Yinchuan plain was formed by deposition of riverlake and flood sediments over a Cenozoic fault basin It isa graben basin based on evolution of the Helan tectonicbelt that experienced numerous rising and sinking processesbetween theMesoproterozoic and Cenozoic eras [17 28]Thepore water aquifers can be divided into two main aquifer




Study area

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

18580000 18590000 18600000 18610000 18620000 18630000

4250000

4260000

4270000

4280000


l flat




Alluvial flat

Yello

w Ri

ver

(km)0 5 10

A

Ningxia University

EWN

S

China

A998400
















1096

1102

1102

1102

110811

08

1108

1114

1114

1120

1120

1126

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

4250000

4260000

4270000

4280000


EWN

S

Flow direction

(km)0 5 10








times 100 (1)






2minus 177 175 84 45 054 2940 250HCO

3


minus 00 2 01 04 346 179 20NH4





3


4




3




3


4


2minus (119903 = 0562) and HCO3






2minus HCO3

minus NO3

minus NH4

+ Fminus



HCO3


NO3


NH4



C30

400

400

400

400

400

500

500

500

600

600

600

700

700

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17C18

C19

C20C22

C24C25

C26C27

C29

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S





3

minus

+ 4H2SiO4

2minus

(2)



3



(3)




20

40

60

80

80 60 40 20 20 40 60 80

80

60

40

20

20

40

60

80

20

40

60

80

SO42minus

HCO3minus

Ca2+

Na+ + K+

Clminus

Mg2+




2involved in the



3

minus (4)

CaCO3+H2O + CO


3

minus (5)


3

minus (6)


2


minus

(7)


3


3






4

2minus+ 2H2O (8)





3

minusrarr HCO

3

minus+

SO4

2minusrarr SO

4

2minus+ HCO

3

minusrarr SO

4


SO4




4



C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)




2minus (mmolL)



3


3-



4


3

minus


4


3-MgsdotCa to HCO

3-



SI = log IAP119870 (9)








Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




Study area

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

18580000 18590000 18600000 18610000 18620000 18630000

4250000

4260000

4270000

4280000


l flat




Alluvial flat

Yello

w Ri

ver

(km)0 5 10

A

Ningxia University

EWN

S

China

A998400
















1096

1102

1102

1102

110811

08

1108

1114

1114

1120

1120

1126

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

4250000

4260000

4270000

4280000


EWN

S

Flow direction

(km)0 5 10








times 100 (1)






2minus 177 175 84 45 054 2940 250HCO

3


minus 00 2 01 04 346 179 20NH4





3


4




3




3


4


2minus (119903 = 0562) and HCO3






2minus HCO3

minus NO3

minus NH4

+ Fminus



HCO3


NO3


NH4



C30

400

400

400

400

400

500

500

500

600

600

600

700

700

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17C18

C19

C20C22

C24C25

C26C27

C29

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S





3

minus

+ 4H2SiO4

2minus

(2)



3



(3)




20

40

60

80

80 60 40 20 20 40 60 80

80

60

40

20

20

40

60

80

20

40

60

80

SO42minus

HCO3minus

Ca2+

Na+ + K+

Clminus

Mg2+




2involved in the



3

minus (4)

CaCO3+H2O + CO


3

minus (5)


3

minus (6)


2


minus

(7)


3


3






4

2minus+ 2H2O (8)





3

minusrarr HCO

3

minus+

SO4

2minusrarr SO

4

2minus+ HCO

3

minusrarr SO

4


SO4




4



C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)




2minus (mmolL)



3


3-



4


3

minus


4


3-MgsdotCa to HCO

3-



SI = log IAP119870 (9)








Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


1096

1102

1102

1102

110811

08

1108

1114

1114

1120

1120

1126

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

4250000

4260000

4270000

4280000


EWN

S

Flow direction

(km)0 5 10








times 100 (1)






2minus 177 175 84 45 054 2940 250HCO

3


minus 00 2 01 04 346 179 20NH4





3


4




3




3


4


2minus (119903 = 0562) and HCO3






2minus HCO3

minus NO3

minus NH4

+ Fminus



HCO3


NO3


NH4



C30

400

400

400

400

400

500

500

500

600

600

600

700

700

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17C18

C19

C20C22

C24C25

C26C27

C29

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S





3

minus

+ 4H2SiO4

2minus

(2)



3



(3)




20

40

60

80

80 60 40 20 20 40 60 80

80

60

40

20

20

40

60

80

20

40

60

80

SO42minus

HCO3minus

Ca2+

Na+ + K+

Clminus

Mg2+




2involved in the



3

minus (4)

CaCO3+H2O + CO


3

minus (5)


3

minus (6)


2


minus

(7)


3


3






4

2minus+ 2H2O (8)





3

minusrarr HCO

3

minus+

SO4

2minusrarr SO

4

2minus+ HCO

3

minusrarr SO

4


SO4




4



C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)




2minus (mmolL)



3


3-



4


3

minus


4


3-MgsdotCa to HCO

3-



SI = log IAP119870 (9)








Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




2minus 177 175 84 45 054 2940 250HCO

3


minus 00 2 01 04 346 179 20NH4





3


4




3




3


4


2minus (119903 = 0562) and HCO3






2minus HCO3

minus NO3

minus NH4

+ Fminus



HCO3


NO3


NH4



C30

400

400

400

400

400

500

500

500

600

600

600

700

700

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17C18

C19

C20C22

C24C25

C26C27

C29

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S





3

minus

+ 4H2SiO4

2minus

(2)



3



(3)




20

40

60

80

80 60 40 20 20 40 60 80

80

60

40

20

20

40

60

80

20

40

60

80

SO42minus

HCO3minus

Ca2+

Na+ + K+

Clminus

Mg2+




2involved in the



3

minus (4)

CaCO3+H2O + CO


3

minus (5)


3

minus (6)


2


minus

(7)


3


3






4

2minus+ 2H2O (8)





3

minusrarr HCO

3

minus+

SO4

2minusrarr SO

4

2minus+ HCO

3

minusrarr SO

4


SO4




4



C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)




2minus (mmolL)



3


3-



4


3

minus


4


3-MgsdotCa to HCO

3-



SI = log IAP119870 (9)








Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




2minus HCO3

minus NO3

minus NH4

+ Fminus



HCO3


NO3


NH4



C30

400

400

400

400

400

500

500

500

600

600

600

700

700

Shilidun

Nongmuchang

Zhenbeibu

Lianyouchang

Nongkesuo

Luhuatai

Liangtian

Fengdeng

Yinchuan

Wangyuan

Helan

Zhangzhen

Jinggui

Ligang

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17C18

C19

C20C22

C24C25

C26C27

C29

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S





3

minus

+ 4H2SiO4

2minus

(2)



3



(3)




20

40

60

80

80 60 40 20 20 40 60 80

80

60

40

20

20

40

60

80

20

40

60

80

SO42minus

HCO3minus

Ca2+

Na+ + K+

Clminus

Mg2+




2involved in the



3

minus (4)

CaCO3+H2O + CO


3

minus (5)


3

minus (6)


2


minus

(7)


3


3






4

2minus+ 2H2O (8)





3

minusrarr HCO

3

minus+

SO4

2minusrarr SO

4

2minus+ HCO

3

minusrarr SO

4


SO4




4



C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)




2minus (mmolL)



3


3-



4


3

minus


4


3-MgsdotCa to HCO

3-



SI = log IAP119870 (9)








Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


20

40

60

80

80 60 40 20 20 40 60 80

80

60

40

20

20

40

60

80

20

40

60

80

SO42minus

HCO3minus

Ca2+

Na+ + K+

Clminus

Mg2+




2involved in the



3

minus (4)

CaCO3+H2O + CO


3

minus (5)


3

minus (6)


2


minus

(7)


3


3






4

2minus+ 2H2O (8)





3

minusrarr HCO

3

minus+

SO4

2minusrarr SO

4

2minus+ HCO

3

minusrarr SO

4


SO4




4



C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)




2minus (mmolL)



3


3-



4


3

minus


4


3-MgsdotCa to HCO

3-



SI = log IAP119870 (9)








Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


C07C09

C10

C11C12C15C16C17

C19

C21

C23C26

C28

C29

C30

C33

C04

C05

C06C08C1 3C14 C24 C25

0

1

2

3

4

1 2 3 40

Clminus

Na+

(a)

C01C02

C03

C07C09C10

C11C12C15C16C17C18

C19C20

C21

C22

C23

C26 C27

C28C29

C30

C32

C33

C04

C05C06

C08C13C14C24C25

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 90

Ca2+

HCO3minus

(b)

C01C02

C03

C07C09

C10

C11C12C15C16C17C18

C19C20

C21

C22C23

C26

C27

C28

C29

C30

C32C33

C04

C05C06C08

C13C14

C24C25

1 2 3 4 5 6 7 8 9 1000

1

2

3

4

5

6

7

8

9

10

HCO3minus

Ca2++

Mg2

+

(c)

C01C02 C03

C07C09

C10

C11

C12C15

C16

C17

C18

C19C20

C21

C22C23C26

C27

C28

C29

C30

C32C33

C04

C05C06

C08

C13C14C24C25

0

1

2

3

4

5

1 2 3 4 50

SO42

minus

Ca2+

(d)




2minus (mmolL)



3


3-



4


3

minus


4


3-MgsdotCa to HCO

3-



SI = log IAP119870 (9)








Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







Clminus(10)


HCO3

minus+ SO4

2minus+ CO3

2minus+ NO

3

minus(11)




3

minus SO4

2minus Clminus NH4

+ NO3

minus and Fminus




3036 071 minus023 minus036







4



(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(meqL)(meqL)

NaUpgradient

Ca

Mg

Cl

3

C11

32 15 4 4 51 2

SO4

HCO3

(meqL)(meqL)

SO4

HCO3

Downgradient

C19

Na

Ca

Mg

Cl

24 08 16 24 32 416 084 32

(a)

C08

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

SO4

HCO3

Downgradient

C07

5

Na

Ca

Mg

Cl

(meqL) (meqL)4 3 2 1 1 2 3 4 5

Upgradient

SO4

HCO3

(b)




4





3



3




minus



C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28minus15

minus15

minus125

minus125

minus175

minus2

minus175

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus125

minus15

minus15

minus1

(a)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

minus655

minus655

minus655

minus68minus705

minus68

minus68

(b)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

05

08

08

08

1

1

1

1

14250000

4260000

4270000

428000018

6300

00

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(c)

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

225

25

25

25

28 28

28

28

28

3

3

3

3

3

32

32

32

4250000

4260000

4270000

4280000

1863

0000

1858

0000

1859

0000

1860

0000

1861

0000

1862

0000

EWN

S

(km)0 5 10

(d)


while high NO3


3

minus







00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


00

0

0

04

04

04

04

11

1

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

minus1

minus1

(a)

02

02

02

02

02

1222

32

C01

C02

C03

C04C05

C06

C07

C08C09

C10

C11

C12

C14

C15

C17 C18C19

C20C22

C24C25

C26C27

C29

C30

C32

C33

C13

C16

C21C23

C28

18580000 18590000 18600000 18610000 18620000 18630000

(km)0 5 10

4250000

4260000

4270000

4280000 EWN

S

(b)







5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




5 Conclusions



Clminus and NH4





Competing Interests


Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Research Article Multivariate Analysis of Confined...

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