Assessment of groundwater quality
Water samples from this study area are generally less than 10% which is estimated (Fig.2). The box plot is a simple visualization with respect maxima and minima identified by the data variation (Fig.3) of diverse region of the study area for the drinking purposes of groundwater quality assessed.
GW Quality for drinking Usage
One of the these techniques box plot which is used for to visually summarize and compare groups for drinking suitability at kompur and pappiredipatti in Figs 4 and 5. Both have good to moderate water quality in this region based on BIS standard.
Major ion variation in different water types are shown in fig 6. Scatter diagram shown in Fig.7 relation between Na vs Cl. Geology of the study area is primary factor for controlling the quality of natural water system. In the natural condition in the chemical composition, rainfall ranges between the temperatures of this region show in the process of evaporation.
Ludwig langelier plot is an appropriate grouping of cations and anions have been plotted as percentages. Generally, this type of Ludwig langelier is used to plot percentage of Na+K against percentage of HCO3+%SO4. In this plot, Ca+Mg and Cl their percentage are also fixed: Fig.7 plot displays relative ratios rather than absolute concentrations
Mechanisms controlling hydrochemical composition
The chemical components of water to their respective aquifers and the groundwater chemistry in the rock and their connection of including chemistry of the rock types, chemistry of brought on water, and rate of evaporation have been recognized. Gibbs (1970) diagram has illustrated in which ratio between dominant of anions and cations have plotted in opposition to the fee of Total Dissolved Solid. Anions [Cl/(Cl+ HCO3)] and Cations [(Na+K)/(Na+K+Ca)] as a function of TDS are broadly employed to dissolved chemical parts inclusive of precipitation fall in upper region mostly ,rock and evaporation dominance in lower region. (Gibbs1970) gibbs diagrams are representing the ratio. The chemical water data of groundwater samples are plotted inside the Gibbs diagram (Figs. 9). Influencing in weathering of rock-forming minerals of groundwater through dissolution of rock via which water is circulating through ions of the water.
Evaporation
Groundwater samples are indicates the relation between Na (meq/l) versus Cl (meq/l) in Fig.10 and Na/Cl (meq/l) versus EC in Fig.11. Both are shown evaporation is not major part of process. This process is slightly inclined relationship. The slightly elevated Na is indicating silicate weathering than evaporation. In this area Na is higher because of granite gneiss monitored by evaporation process.
Cation-exchange response
This process which control occurrence and distribution of ions using this reaction it can be identified which is contamination sources. Excess Cl over Na this demarcates ion exchange process (Fig.12).
Silicate weathering process
Evidence of silicate weathering can be elucidated by Relation between Ca+Mg versus HCO3in Fig 13. This situation required CO3 alkalinity to be balanced by alkalis. Relation between Ca+Mg versus Total cationin Fig.14 and Relation between Na+K versus Total cationin Fig.15. The most of data points 1:1 equiline. The total cation are indicating silicate weathering when contribution higher in this case. Na probable source is silicate dissolution because it derived from silicate weathering. In this study the major source of cation and HCO3 occurred by silicate process of weathering and also Ca and Mg by common minerals in granitic gneissic rock.
Soil leaching indicated in Fig.16. The boxes represent in Fig.17 without any mixing, the tiers of approximate compositions of the three important supply end individuals such as carbonate dissolution, Silicate weathering and Evaporate dissolution) (after Zhu et al.,2011)