Statistical Assessment of Physico-chemical Parameters of Water from Bore Holes and Shallow Wells in Agateeswaram and Kalkulam Taluks of Kanyakumari District, India

A systematic study has been carried out to explore physico-chemical parameters of drinking water from bore holes and shallow wells in five different stations (sites) of Agasteeswaram and Kalkulam Taluks in Kanyakumari District of South India. Water samples from bore holes and shallow wells in five stations were collected and analyzed for temperature, pH, turbidity, alkalinity, hardness, salinity, fluoride, chloride, total dissolved solids, dissolved oxygen, BOD, electrical conductivity, total nitrogen, nitrate, sulphate, ammonia, phosphate, total phosphorus, sodium, potassium and oxidation & reduction potential. Comparative studies of parameters in different stations and in different Taluks were also carried out. The physico-chemical parameters were analyzed and the results were compared with water quality standards described by WHO. Statistical techniques, calculation of basic statistics, Correlation matrix, Hierarchical Cluster analysis were simultaneously applied to the physico-chemical parameters of water samples taken from in different stations and in different Taluks. The above study will be useful to know the water quality and their fitness for drinking purposes at various stations undertaken. Overall water quality was found satisfactory for drinking purpose without prior treatment.


Introduction
The life of living organism depends on water [1][2][3][4] . The main source of life for many people in the world is the ground water [5] . The pollution of surface and ground water is a major problem due to rapid urbanization and industrialization [6] . The water demand is continuously increasing mainly due to population growth and raising needs in agriculture, industrial uses and domestic services [7] . Several studies on the ground water quality have been carried out in different parts of India [8][9][10][11] . Kanyakumari district is divided into four Taluks. The district is part of the composite east flowing river basin "between Pazhayar and Tamirabarani" as per the irrigation Atlas of India [12] . People in Kanya Kumari district depends on bore holes and shallow wells for domestic purpose. The quality of water from bore holes and shallow wells are to be analyzed. The objective of this study is to investigate physico-chemical analysis and statistical analysis of parameters of water from bore holes and shallow wells in our study area. Study area consists of four Taluks namely Agasteeswaram, Kalkulam, Vilavamcode and Thovalai. But at present, we liberate the results of the Agasteeswaram and Kalkulam Taluks.

Temperature
The temperature was found to be range between 26 to 28 o C during study. pH pH is an indicative of acidity or basicity of water. The pH values of bore holes water varied between 6.2 to 7.7 for B1 to B5, 7.0 to 7.9 for B6 to B10 (Tables 1, 3), 6.3 to 6.8 for S1 to S5, 6.0 to 6.8 for S6 to S10 (Tables 5,7). The mean pH of bore hole water found to be 6.92 for B1 to B5 ad 7.38 for B6 to B10. This shows that water smples from bore hole of Agateeswaram Taluk is almost neutral but water samples from Kalkulam Taluk is slightly alkaline trend. The mean pH of shallow wells water found to be 6.48 for S1 to S5 and 6.42 for S6 to S10. This shows that water smples from shallow wells of both Taluks are slightly acidic trend. The pH of water is influenced by geology of catchments area and buffering capacity of water.

Turbidity
Turbidity is a measure of the light scattering potential of water caused by the presence of colloidal and suspended material. The turbidity values of bore holes water varied between 7.6 to 7.9 for B1 to B5, 7.0 to 7.6 for B6 to B10 (Tables 1, 3), 5.4 to 5.8 for S1 to S5, 5.0 to 5.8 for S6 to S10 (Tables 5, 7). The mean turbidity of bore hole water found to be 7.72 for B1 to B5 ad 7.20 for B6 to B10. The mean turbidity of shallow wells water found to be 5.50 for S1 to S5 and 5.28 for S6 to S10. The limit of turbidity value for drinking water is specified as 5 to 10 NTU. The observed turbidity values are within the permissible limits.

Electrical conductivity
The EC values of bore holes water varied between 625 to 730 for B1 to B5, 600 to 790 for B6 to B10 (Tables 1, 3), 600 to 650 for S1 toS5, 600 to 631 for S6 to S10 (Tables 5,7). The mean EC of bore hole water found to be 695.20 for B1 to B5 and 704 for B6 to B10. The mean EC of shallow wells water found to be 628.40 for S1 to S5 and 620.80 for S6 to S10. The observed values are within the permissible limits.

Total dissolved solids (TDS)
ISI prescribed desirable limit of TDS is 500 mg/L. TDS values observed in B1 to B10 and S1 to S10 were low and with the desirable limit. The low value indicates that there is not much pollution by particles. The TDS values of bore holes water varied between 61 to 64 for B1 to B5, 62 to 80.0 for B6 to B10 (Tables 1, 3), 36 to 37 for S1 to S5, 35.80 to 37.50 for S6 to S10 (Tables 5, 7). The mean TDS of bore hole water found to be 62.4 for B1 to B5 and 72.60 for B6 to B10. The mean TDS of shallow wells water found to be 36.50 for S1 to S5 and 36.56 for S6 to S10.

Sodium (Na+) and potassium (K+)
The concentration of Na values of bore holes water varied between 18.2 to 19.8 for B1 to B5, 17.9 to 19.80 for B6 to B10 (Tables 1, 3), 13.00 to 16.00 for S1 to S5, 15.0 to 16.0 for S6 to S10 (Tables 5, 7). The mean concentration of Na of bore hole water found to be 19.09 for B1 to B5 and 18.62 for B6 to B10. The mean concentration of Na of shallow wells water found to be 14.94 for S1 to S5 and 15.52 for S6 to S10. The observed values are within the permissible limits.
The concentration of K values of bore holes water varied between 12.9 to 14.7 for B1 to B5, 13.90 to 15.50 for B6 to B10 (Tables 1, 3), 11.50 to 12.20 for S1 to S5, 11.20 to 13.90 for S6 to S10 (Tables 5, 7). The mean concentration of K of bore hole water found to be 13.81 for B1 to B5 and 14.61for B6 to B10. The mean concentration of K of shallow wells water found to be 11.84 for S1 to S5 and 12.74 for S6 to S10. The observed values are within the permissible limits.

Alkalinity
Alkalinity of water is a measure of its capacity to neutralize acids and provides an index for the nature of slats present in the water samples. The standard desirable limit of alkalinity in drinking water is 120 mg/L. The maximum permissible level is 600 mg/L. The alkalinity values of bore holes water varied between 180 to 191 for B1 to B5, 190 to 200 for B6 to B10 (Tables 1, 3), 140 to 160 for S1 toS5, 140 to 153 for S6 to S10 (Tables 5, 7). The mean alkalinity of bore hole water found to be 184.6 for B1 to B5 and 195.80 for B6 to B10. The mean alkalinity of shallow wells water found to be 147 for S1 to S5 and 149.20 for S6 to S10. The observed alkalinity values are within the permissible limits.

Calcium and Magnesium
The upper limit of calcium concentration in drinking water is specified as 75 mg/L (ISI, 1983). The Ca values of bore holes water varied between 60.0 to 69.0 for B1 to B5, 63.0 to 71.0 for B6 to B10 (Tables 1, 3), 50 to 56 for S1 to S5, 52 to 57 for S6 to S10 (Tables 5, 7). The mean Ca of bore hole water found to be 63.20 for B1 to B5 ad 68.20 for B6 to B10. The mean Ca of shallow wells water found to be 53.40 for S1 to S5 and 55.20 for S6 to S10. observed values are within the permissible limits.
The upper limit of magnesium concentration in drinking water is specified as 30 mg/L (ISI, 1983). The Mg values of bore holes water varied between 1.4 to 1.6 for B1 to B5, 1.5 to 2.20 for B6 to B10 (Tables 1, 3), 1.25 to 1.40 for S1 toS5, 1.20 to 1.80 for S6 to S10 (Tables 5, 7). The mean Mg of bore hole water found to be 1.50 for B1 to B5 and 1.86 for B6 to B10. The mean Mg of shallow wells water found to be 1.27 for S1 to S5 and 1.48 for S6 to S10. The observed values are within the permissible limits.

Fluoride
Fluoride content is an important factor in the development of normal bones and teeth The desirable limit is 1 to 1.5 mg/L for drinking purpose. Fluoride values observed in B1 to B10 and S1 to S10 were low and with the desirable limit. The Fluoride values of bore holes water varied between 0.7 to 0.8 for B1 to B5, 0.6 to 0.80 for B6 to B10 (Tables 1, 3), 0.4 to 0.60 for S1 toS5, 0.4 to 0.60 for S6 to S10 (Tables 5, 7). The mean Fluoride of bore hole water found to be 0.76 for B1 to B5 and 0.70 for B6 to B10. The mean Fluoride of shallow wells water found to be 0.50 for S1 to S5 and 0.54 for S6 to S10.

Chloride
Chloride is a most common inorganic anion present in water to it through biogenic sources and indicates the sate of contamination. The chloride values of bore holes water varied between 250 to 280 for B1 to B5, 225 to 240 for B6 to B10 (Tables 1, 3), 209 to 230 for S1 to S5, 203 to 210 for S6 to S10 (Tables 5, 7). The mean chloride of bore hole water found to be 262 for B1 to B5 and 232 for B6 to B10. The mean chloride of shallow wells water found to be 217.80 for S1 to S5 and 206.40 for S6 to S10. The observed values are within the permissible limits.

Nitrate
The nitrate values of bore holes water varied between 0.5 to 0.8 for B1 to B5, 0.6 to 0.8 for B6 to B10 (Tables 1, 3), 0.4 to 0.50 for S1 to S5, 0.4 to 0.6 for S6 to S10 (Tables 5,7). The mean nitrate of bore hole water found to be 0.60 for B1 to B5 and 0.74 for B6 to B10. The mean nitrate of shallow wells water found to be 0.48 for S1 to S5 and 0.50 for S6 to S10. The observed values are within the permissible limits.

Sulphate
Sulphate is the major anion occurring in natural waters. The upper limit for sulphtae concentration for drinking water is 150 mg/L. The Sulphate values of bore holes water varied between 5.0 to 5.8 for B1 to B5, 5.90 to 6.70 for B6 to B10 (Tables 1, 3), 4.38 to 4.60 for S1 to S5, 4.40 to 4.80 for S6 to S10 (Tables 7,10). The mean Sulphate of bore hole water found to be 5.38 for B1 to B5 and 6.26 for B6 to B10. The mean Sulphate of shallow wells water found to be 4.47 for S1 to S5 and 4.62 for S6 to S10. The observed values are within the permissible limits.

Phosphate
The phosphate ion in the water samples due to agriculture land composition of organic matter. The Phosphate values of bore holes water varied between 0.8 to 0.9 for B1 to B5, 0.79 to 1.10 for B6 to B10 (Tables 1, 3), 0.60 to 0.75 for S1 to S5, 0.40 to 0.80 for S6 to S10 (Tables 5, 7). The mean Phosphate of bore hole water found to be 0.85 for B1 to B5 and 0.93 for B6 to B10. The mean Phosphate of shallow wells water found to be 0.65 for S1 to S5 and 0.65 for S6 to S10. These values are within the permissible limits.

Salinity
The salinity values of bore holes water varied between 70.0 to 83.0 for B1 to B5, 70.0 to 82.0 for B6 to B10 (Tables  1, 3), 28 to 52 for S1 to S5, 25 to 72 for S6 to S10 (Tables  5,7). The mean salinity of bore hole water found to be 76.4 for B1 to B5 and 74.6 for B6 to B10. This shows that water smples from bore hols of of both Taluks are slightly alkaline trend. The mean salinity of shallow wells water found to be 38 for S1 to S5 and 47 for S6 to S10. The observed values are within the permissible limits.

Dissolved Oxygen
It is one of the most fundamental parameters in water, as it is to the metabolism of of all aerobic aquatic organisms. The permissible limit of DO for drinking water is 6 mg/L. DO values observed in B1 to B10 and S1 to S10 were low and with the desirable limit. The pH values of bore holes water varied between 5.2 to 6.0 for B1 to B5, 5.80 to 7.0 for B6 to B10 (Tables 1, 3), 6.3 to 7.2 for S1 to S5, 6.0 to 7.4 for S6 to S10 (Tables 5,7). The mean DO of bore hole water found to be 5.58 for B1 to B5 and 6.38 for B6 to B10. The mean DO of shallow wells water found to be 6.64 for S1 to S5 and 6.88 for S6 to S10.

Biochemical oxygen demand
The permissible limit for BOD as per WHO is 5 mg/L. The BOD values of bore holes water varied between 4.5 to 5.2 for B1 to B5, 4.60 to 5.80 for B6 to B10 (Tables 1, 3), 4.00 to 5.30 for S1 toS5, 4.60 to 6.4 for S6 to S10 (Tables 5, 7). The mean BOD of bore hole water found to be 4.90 for B1 to B5 and 5.26 for B6 to B10. The mean BOD of shallow wells water found to be 4.90 for S1 to S5 and 5.66 for S6 to S10.

Oxidation Reduction potential
The ORP values of bore holes water varied between 600 to 650 for B1 to B5, 610 to 635 for B6 to B10 (Tables 1, 3), 560 to 615 for S1 to S5, 572 to 590 for S6 to S10 (Tables 5,  7). The mean ORP of bore hole water found to be 620 for B1 to B5 and 623 for B6 to B10. The mean ORP of shallow wells water found to be 583 for S1 to S5 and 580 for S6 to S10. The shallow well water samples have less ORP value as compared to bore hole water samples. This indicates more oxygen present in bore hole water.
The Pearson correlation analysis was ferformed for measured parameters to determine the relation between these variables and given in Tables 9, 10, 11, and 12 respectively. A correlation analysis is a bivariate method applied to describe the degree of relation between two hydro chemical parameters. A high correlation coefficient (near 1 or -1) means a good relationship between two variables and its value around zero means no relationship between them at a significant level of <0.05. More precisely it can be said that parameters showing coefficient >0.7 are considered to be strongly correlated where as coefficient between 0.5 and 0.7 shows moderate correlation.
Statistical Assessment of Physico-chemical Parameters of Water from Bore Holes and Shallow Wells in Agateeswaram and Kalkulam Taluks of Kanyakumari District, India  Cluster analysis (CA) was used for multivariate modeling of the input data [16] . The main goal of the Hierarchical Agglomerative cluster analysis to spontaneously classify data into groups of similarity ( cluster) searching objects in the n-dimensional space located in closest neighbourhood and to separate a stable cluster from other clusters.
In figure 26, the hierarchical dendrogram for the clustering of determined physical and chemical parameters for all the studied stations is plotted ( Ward's method of linkage, squared Euclidean distance as similarity measure, standardization of the input data). For clustering altogether 22 physical and chemical parameters were chosen ( indicated in Table 1). It could be concluded that the one big cluster and three small clusters are formed. Additionally sub clusters are also formed.  figure 27, the hierarchical dendrogram for the clustering of determined physical and chemical parameters for all the studied stations is plotted ( Ward's method of linkage, squared Euclidean distance assimilarity measure, standardization of the input data). For clustering altogether 22 physical and chemical parameters were chosen ( indicated in Table 3). It could be concluded that the one big cluster and two small clusters are formed. Additionally sub clusters are also formed.
Sub cluster 1: Sodium, alkalinity Cluster 2 ( two parameters are included): Alkalinity, chloride Sub cluster 2: EC, TDS Cluster 3 ( two parameters are included): EC, OXREDPot. In figure 28, the hierarchical dendrogram for the clustering of determined physical and chemical parameters for all the studied stations is plotted ( Ward's method of linkage, squared Euclidean distance assimilarity measure, standardization of the input data). For clustering altogether 22 physical and chemical parameters were chosen ( indicated in Table 5). It could be concluded that the one big cluster and three small clusters are formed. Additionally sub clusters are also formed. Cluster 1( fourteen parameters are included) Fluoride figure 29, the hierarchical dendrogram for the clustering of determined physical and chemical parameters for all the studied stations is plotted ( Ward's method of linkage, squared Euclidean distance assimilarity measure, standardization of the input data). For clustering altogether 22 physical and chemical parameters were chosen ( indicated in Table 7). It could be concluded that the one big cluster and three small clusters are formed. Additionally sub clusters are also formed.