Multivariate Water Quality Assessment of Renowned Pilgrim Spot, Gujarat, India: A Statistical Approach

Gomti Palustrine Habitat is one of the renowned pilgrimage ponds of Central Gujarat, India. In the present research, different statistical tests were applied to 21 water quality parameters to trace and delineate the status of water quality. The present study was undertaken for one year (December, 2012 to November, 2013) with monthly sampling covering three successive seasons (winter, summer, monsoon). Three permanent sampling stations (V1, V2, V3) were selected to cover the cross-sectional and diagonal regime of wetland. Ionic Signatures (IS) confirmed the wetland to be dominated with Ca and HCO3 -, indicating leaching of minerals from drainage basins. Index of Base Exchange (IBE) supported the enrichment of Na+ ions in the water regime owing to clay horizons. Exchangeable Sodium Ratio (ESR) (1.416 meq/l) and Sodium Absorption Ratio (SAR) (1.367 meq/l) found to be minimal referring to leaching and dissolution of salts during precipitation. Surface water quality is exhibited by low Salinity and low Sodicity zone, can be used for irrigation purpose. Principal Component Analysis (PCA) identified a reduced number of mean of 3 varifactors indicating that 93.35 % of temporal and spatial changes affect the water quality drastically. First factor from the factor analysis explained a total of 74.44 % among TH, HCO3 -, Mg, Cl, salinity and K+. One way ANOVA revealed that Sampling Site 2 is maximally loaded with aquatic pollutants, followed by Sampling Site 3 and Sampling Site 1 (Site description is given in the later section of the paper). These outcomes manifested prime necessity to restore the physical, chemical and biological integrity of water quality to revert the ecological balance of an aquatic ecosystem. Current World environment Journal Website: www.cwejournal.org ISSN: 0973-4929, Vol. 12, No. (3) 2017, Pg. 586-599 ConTACT Hiren B. Soni drhirenbsoni@gmail.com Department of Environmental Science & Technology (EST), Institute of Science & Technology for Advanced Studies & Research (ISTAR), Vallabh Vidyanagar 388 120 (Gujarat) India. © 2017 The Author(s). Published by Enviro Research Publishers This is an Open Access article licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-nc-sa/4.0/ ), which permits unrestricted NonCommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. To link to this article: http://dx.doi.org/10.12944/CWE.12.3.10 Article history Received: 13 November 2017 Accepted: 21 December 2017


Introduction
So far liminological studies have been mainly aimed to focus on deterioration of the water quality due to pollution only on the part of human consideration.Now-a-days, pilgrimage ponds visited by number of pilgrims are an addition to many folds to this devastation, which has now become a cause of global concern 18 .The productivity of the pond mainly depends on various abiotic and biotic components usually fluctuated by seasonal and varying degree of pollution 3 .Hydro-chemistry of water plays a paramount role in determining the distribution and pattern, and quantitative abundance of an aquatic ecosystem 36 .Water quality assessment approach allows the physical, chemical, and biological characterization of the water to be considered in light of their probable impact on advantageous uses of the water by humans.For the past many years, investigators have studied the hydro-biological profile of many lentic ecosystems with the intent to assess the water quality 34,32,12,31 .Recently, 38 reported the hydro-quality profile of pilgrimage wetland of Central Gujarat.In past, biotic components viz.occurrence of plankton of Gomti Palustrine Habitat (GPH) were investigated 39,40 , but mere focus was paid on status of surface water quality for the aforesaid study area.Present study deals with the multivariate approach to speculate the degree of fluctuations of significant hydro-chemical parameters of surface water at Gomti Palustrine Habitat (GPH), Central Gujarat, India, owing to non-point anthropogenic interventions, consequentially imparting pessimistic impact on aquatic body, which perhaps will help in plummeting human pressures distressing on the selected renowned pilgrimage freshwater spot aided with some conservation and management strategies.

Study Area
Gomti Palustrine habitat (GPh) Gomti Palustrine Habitat (GPH), Central Gujarat, India, is located between 22.59 0 N and 72.87 0 E; with an average humidity 52 %; winter temperature 19 0 C and 33 0 C during summer; mean elevation 37 meters above MSL, 8733 human population with 72 % literacy rate.The wetland covers an area of approximately 173 acres.From the spirituality point of view, this pilgrim spot is the most worshiped holy place of Lord Swaminarayana (the incarnation of Lord Krishna), solemnised with ancient galore and varying rituals, hence fetching the source of sacredness for the pilgrims from all over the State and the Country.(Fig. 1).

Samppling Sites Sampling Site V1
This Site is situated at the southern end of GPH adjacent to village (Vadtal).The mean water depth of this Site is around 6.096 m during monsoon; however, water level recedes during summer.The water at this Site is comparatively unpolluted than the other two study Sites.The dominant macrophytes at this Site are Hydrilla verticillata (L.f.) Royle, Azolla pinnata R. Br., and Ipomoea aquatica Forsk.Fishing by the local anglers has been a regular activity therein.Sometimes, cattle wading and bathing is also noticed here.

Sampling Site V2
This Site is situated westwards to the wetland which is highly polluted with organic matter owing to its proximity to agricultural plots in addition to influent of raw sewage from nearby households.Amount of organic wastes frequently is dumped at this Site due to unchecked input of detergents and household wastes, generated from washing, bathing and cattle wading activities by the locales.Moreover, garlands, clothes, coconuts, etc. are also discarded in the form of temple wastes into this Site.The villagers use the water of this Site, mainly for washing clothes and utensils, and thus detergent wastes reaches to high amounts.

Sampling Site V3
This Site is situated towards the northern side of the wetland.The floral aquatic plant species dominating the Site are Eichhornia crassipes (Mart.)Solms., Lemna minor L., Ipomoea aquatica Forsk., with uncommon occurrence of Ceratophyllum demersum L., Najas minor All. and Marsilea quadrifolia L. Dumping of plastic bottles and menace tourism wastes by local bus passengers are observed therein due to Site proximity near local bus stop and road transport network

Surface Water Sampling
The present study was undertaken for one year (December, 2012 to November, 2013) with monthly sampling , covering three successive seasons (winter, summer, monsoon).Three permanent sampling stations (V1, V2, V3) were selected to cover the cross-sectional and diagonal regime of wetland.Collection of surface water samples were done using pre-cleaned polyethylene bottles (two litres), filtered using 0.45 micron filters, and stored in ice boxes at 4 0 C for further laboratory analysis.Standard protocol was adopted for surface water analysis 44,19,11,1 .
Statistical analysis is one of the best techniques for stipulating linear relationship between different variables (parameters) 13 .In order to quantitatively analyse and confirm the relationships amongst the variables, its scientific reliability was validated using Correlation Coefficient (r), Ion Signatures (IS), Index of Base Exchange (IBE), Sodium Absorption Ratio (SAR), Principal Component Analysis (PCA), and One Way ANOVA (Analysis of Variance), using PAST Software, Version 3.03, SPSS version 22.0, STATISTICA 9 and Aq.QA Software [Version 1.1.1(1.1.5.1)].

Results and Discussion
Surface Water Quality Analysis of hydro-chemical constituents of GPH at sampling points is shown in Table 1.Results indicated that pH increased from 7.50 to 7.53.TDS ranged between 163.61 to 175.28 ppm.According to 6 , surface water quality is of fresh type (TDS < 1000 ppm).DO ranged between 4.92-5.39ppm, referring to a bit hypoxic condition of water body.TH fluctuated from 168.28 to 178.02 ppm, symbolizes the moderatel hard water quality (TH > 300 ppm; 45 The outcomes of Aq.QA Software [Version 1.1.1(1.1.5.1)] delineate the pilgrim wetland as a dominant water type (Na-HCO 3 -type).Na-HCO 3 -composition may be due to weathering of carbonaceous sandstones (consistent with geological signatures) or may be due to interaction with schist, quartzite, and granite rocks.Exchangeable Sodium Ratio (ESR) is 1.416 meq/l, and Sodium Absorption Ratio (SAR) is 1.367 meq/l.The surface water quality of entire study area falls under C1-S1 low salinity-low sodicity zone 47 , and low SAR (Sodium Absorption Ratio = Na + / {[Ca 2+ + Mg 2+ ] / 2} * 0.5) zone.SAR is found to be lower indicating leaching and dissolution of salts during precipitation 43 .As the surface water quality is exhibited by low salinity and low sodicity zone, the water is of good water type, and can be used for irrigation purpose with little menace of exchangeable sodium 47 .The impact of geological and anthropogenic activities on the hydro-chemistry of surface water can further be extrapolated with the help of scatter diagrams, ionic signatures 49 .

Ionic Trends
Overall scenario of the ionic trends of water quality is well-depicted (Fig. 2).All the water quality parameters were reported to be significantly higher at Site 2, followed by Site 3 and least at Site 1.
Except for few parameters (Free CO 2 , NO 3 2-and DO), reverse trend was noticed.The lesser content of DO at Sites 2 and 3 can be attributed by the fact that higher concentration of nutrients at these sites adversely affects the solubility of oxygen in water 2 .Content of DO was observed to be high in the colder season, which can be ascribed to low atmospheric and water temperature, indirectly increasing the solubility of oxygen in water.These findings are in agreement with the investigation of [16][17][18][19][20][21][22][23][24] .Similarly, free CO 2 concentration was found to be higher in the winter season, which might be due to low temperature and high rate of decomposition 8 .Similar trend was well-corroborated with the findings of 15 .
Higher concentration of Free CO 2 at Site 1 was due to excessive content of organic loading in surface waters of a particular site.The term "solids" refers to the total amount of organic and inorganic materials in water 14 , of which Total Suspended Solids (TSS) refers to an indicator parameter referring to the amount of organic pollution 20 .Concentration of solids was observed higher in warmer months due to the evaporative loss of water and subsequent increase in solute concentration in surface water 48 .
Gradual depletion during the hotter months is due to the sedimentation of salt particles with low content of suspended organic matter 35 .Total alkalinity in surface water is mainly due to salts of carbonates, bicarbonates and hydroxides 28 .Increase in carbonates and bicarbonates leads to increase in the concentration of alkalinity 25 .Temporary hardness was noted to be elevated during the warmer months due to an increase in temperature, which eventually leads to high rate of evaporation of surface water, and decomposition and solubility of calcium and magnesium ions, thus concentrating the salts 9 .Temporal concentration of chloride recorded to be higher in summer season due to higher pollution level, owing to low water depth leading to an increase in concentration of organic matter 26,42 .These finding were well-corroborated with the findings of 48,20 .

Fig. 2: Spatial trend of physico-chemical parameters of surface water at sampling points
In case of nutrient concentration, sulphate reported to be maximum in the summer season, which might be due to higher evaporation rate as per 9 .Spatial heterogeneity indicated average concentration of sulphate to be higher at Site 2 compared to other sites due to an increase in bathing and washing practices by local inhabitants as well as pilgrims.This finding was also supported by 33 .Phosphate is one of the limiting and basic nutrients of the static waters 46 .Presence of phosphate in water indicates pollution through domestic sewage, agricultural run-off and certain biological processes 27 .In the present study, the content of phosphate was estimated to be higher in dry seasons with the decline in the water level.Decomposing of organic matter, human indulgence, and loading of domestic sewage through point and non-point sources make the hydric water to be more phosphate rich 4 .Results points towards increasing concentration of phosphate ion at Site 2 compared to other sites, and during dry seasons its concentration increased with gradual decrease during the colder months.Nitrate in the present study was found to be eventually increasing during the colder months due to higher rate of biotic components viz.aquatic macrophytes and plankton community as earlier reported 38 (Fig. 3.) (Table 1).

Fig. 3: Temporal trend of physico-chemical parameters of surface water over different seasons Table 2: Co-relational matrix (r) among physico-chemical variables
Temperature influences all the variables in the lentic ecosystem directly or indirectly.Here, temperature is positively correlated with all the variables except DO, free CO 2 and NO 3 2-.The inverse relationship between DO and temperature is well documented in the literature of 22,17 .A significant positive correlation was computed between DO, free CO 2 and NO 3 2-, indicating all three parameters are interrelated with one another, influenced by their presence there in.Negative correlation between free CO 2 and nitrate with all other hydro-chemical parameters is in agreement with the investigation of 23 .Solid contents of the surface water were positively correlated with all other parameters except DO, free CO 2 and NO 3 2-.The obtained results from the correlation matrix are parallel with the findings of 37 .Calcium and magnesium neutralizes the excess amount of acids present in the water body.This is justified by the high positive correlation in case of TH, and Ca-Mg hardness with alkalinity 5 .The chloride content of water was positively correlated with almost all parameters except DO, free CO 2 and NO 3 2-.These findings matched the study of 8 .Nutrients were significantly positively correlated with the all other variables except DO, Free CO 2 , which is in agreement with the findings of 21 (Table 2).

Ionic Signatures
The hydro-chemical data for two of the sampling sites with respect to Ca + and Mg + ions (alkaline earth elements) / HCO 3 -lies on the equiline for 66 % of the sampling points, suggesting that both alkalinity and alkalis concentration are balancing each other in congruent manner, while for 33 % the ionic profile is lying above the equiline depicting excess of alkalinity is balancing alkalis (Fig A ).The plotting of the ionic data of alkaline earth element to TC (Total Cations) shows that the chemical data for all the study sites lies exactly on the equiline emphasizing on the finding that increase in concentration of alkaline earth elements corresponds to simultaneous increase in the concentration of Total Cations (TC) (Fig B).This indicates a linear relationship between alkalis and cations indicating these ions to be leached from the minerals from the aquifiers.The relative abundance of chloride ion to SO 4 2-is due to the enrichment of water.These ionic signatures from the chemical data refer more strongly to the dominance of Ca -HCO 3 ions in the hydric regime (Fig. 4. A to G).The ionic signature of Na + :Ca 2+ for all study sites is less than a unit indicating the concentration of the alkali earth elements is more than the akalis concentration.Index of Base Exchange (IBE) was further stipulated to study the compositional changes of surface water 46 .The negative value of IBE i.e.IBE I (Cl --Na + +K + : Cl) and IBE II (Cl --Na + +K + : HCO 3 -) support the enrichment of Na+ in water profile owing to prolific clay horizons.The excess amount of Na + ions over K + ions is due to the greater resistance of K + ions to weathering and its absorption to clay minerals 21 .The hydrological regime is dominated by Ca and HCO 3 -, an indication that the composition is controlled by mineral components leached from the rocks of the drainage basins 47 .Moreover, ANOVA interpretation for the dataset indicates that nutrient content was maximum at Site 2 (F = 0.557, p = 0.862), moderate at Site 3 (F = 0.516, p = 0.892), and the least at Site 1 (F = 0.463, p = 0.925) (Table 3)., Mg, Cl, Salinity and K + suggest that first component is related with various hydrochemical processes.In this case, high positive loading between K + and Cl -ions results in more weathering in the sampling area.The positive loading of K + and Mg + ions for the first component indicates weathering of Feldspar and Ferro-magnesium minerals along with anthropogenic sources 51,30 .The concentration of TH and HCO 3 2-suggests that most of the hardness in the water is an ephemeral source.Moderate loading of TDS and NO 3 2-in the surface water samples is the indication of man-made pollution due to domestic waste 7,50,52 (Fig. 5 and Fig. 6.; Table 4 and Table 5).

Table 1 : Physico-chemical constituents of surface water at sampling points
*All the values are expressed in ppm, except pH

Table 3 : one Way Analysis of Variance (AnoVA) for different sampling points
The Principal Component Analysis (PCA) for the surface water of GPH is shown in Tables4 and 5.It includes the loadings of component matrix, Eigen-values for each component, percent, and cumulative percent of variance for each component.It depicts that the first three principal components together accounts for 93.35 % of total variance in the dataset, of which first component is 74.44 %, second component is 9.841% and third component is 9.077 % of total variance.The concentration of TH, HCO 3 2-, Mg, Cl, Salinity and K + shows high positive loadings (0.780-0.799), whereas the concentration of TS, TDS, TH, Ca and PO