Descriptive statistics of 13 parameters of surface and groundwater in the study area are summarized in Tables (1a, 1b). The groundwater pH values varied between 6.69 to 7.68 with mean pH of 7.34 and surface water pH values varied between 6.40 to 8.69 with a mean of pH 7.60. A maximum number of the water samples shows a neutral to basic and alkaline nature. TDS values of groundwater display 110 to 10,000 mg/L and surface water shows 80 to 10,000 mg/L. The prescribed limit of TDS in drinking water is 500mg/L. Observed elevated values of TDS though not injurious to humans but have health effects on individuals suffering from kidney and heart-related ailments. High TDS values indicated health-related issues like laxative or constipation effects (Sasikaran et al. 2012).
The ionic concentrations, pH, TDS in surface water are indicated as electrical conductivity, total dissolved solids. pH value (6.67–8.69) moderately acidic to alkaline, TDS (Total Dissolved Solids) vary from 80 to 10000 mg/L and EC (Electro conductivity) between 0.16 to 20 µs/cm. In groundwater samples concentration, pH value (6.69–7.68 ppm) moderately acidic to alkaline, TDS (Total Dissolved Solids) vary from 400 to 20000 mg/L and EC (Electro conductivity) between 0.80 to 20 µs/cm. Distribution of heavy metals and radiogenic elements in surface and groundwater in the study area occur in the order of Cd < U < Mo < Th < As < Pb < Cr < Cu < Ni < Zn and Cd < Th < Mo < U < As < Cr < Pb < Cu < Ni < Zn respectively.
The correlation coefficient analysis was carried out for ten heavy metals for surface and groundwater as shown in tables (2a, 2b). There was important linearity observed between these metals. The significance of the correlation is based on the ‘r-value which indicates how one metal behaves with the other and the best linearity between the variables is determined by coefficients (-1,1) interval. Higher and positive values of the ‘r-value, indicates the good correlation between the variables and r = 0 indicates a poor correlation, whereas negative values of ‘r’ indicate an inverse relationship. The correlation (Tables 2a, 2b) as noticed in surface water samples As-Cu; As-Pb; Cr-Mo; Cr-Ni; Cd-Cu; Cu-Pb; Cu-Zn; Th-U; and groundwater samples As-Cd; As-Cu; As-Mo; As-U; Cr-Ni; Cd-Mo; Cu-Mo; Cu-U; Mo-U; Pb-Th.
Table 1
a: Descriptive Statistical data (mg/L) of surface water analysis
|
Minimum
|
Maximum
|
Mean
|
Std.
deviation
|
Skewness
|
Kurtosis
|
WHO
|
pH
|
6.40
|
8.69
|
7.60
|
0.53
|
0.29
|
-0.13
|
|
TDS
|
80.0
|
10000
|
4048
|
3913
|
0.48
|
-1.54
|
|
EC(µS /cm)
|
0.16
|
20.0
|
8.50
|
7.78
|
0.34
|
-1.60
|
|
As
|
0.90
|
61.7
|
11.5
|
14.5
|
2.20
|
5.50
|
10
|
Cr
|
7.40
|
125.3
|
14.6
|
8.40
|
1.70
|
2.20
|
50
|
Cd
|
0.10
|
1.70
|
0.60
|
0.40
|
1.10
|
0.70
|
5
|
Cu
|
1.30
|
57.2
|
18.6
|
155
|
1.10
|
0.90
|
2000
|
Mo
|
0.20
|
13.3
|
3.00
|
2.80
|
0.70
|
-0.60
|
|
Ni
|
4.00
|
38.5
|
19.9
|
10.2
|
0.08
|
-0.90
|
70
|
Pb
|
1.10
|
88.6
|
15.2
|
18.7
|
2.80
|
10.0
|
10
|
Th
|
0.50
|
25.1
|
4.60
|
5.80
|
2.20
|
5.50
|
|
U
|
0.01
|
4.10
|
1.00
|
1.10
|
1.20
|
1.10
|
30
|
Zn
|
0.50
|
1288
|
186.8
|
271
|
3.10
|
12.1
|
3000
|
Table 1b: Descriptive Statistical data (mg/L) of groundwater analysis
|
Minimum
|
Maximum
|
Mean
|
Std. deviation
|
Skewness
|
Kurtosis
|
WHO
|
pH
|
6.69
|
7.68
|
7.34
|
0.28
|
-0.98
|
1.276
|
|
TDS
|
110
|
10000
|
2964
|
3863
|
1.23
|
-0.134
|
|
EC(μS /cm)
|
0.80
|
20.0
|
5.91
|
7.72
|
1.23
|
-0.125
|
|
As
|
1.00
|
59.6
|
10.7
|
17.5
|
2.30
|
2.3
|
10
|
Cr
|
8.60
|
19.8
|
10.8
|
2.90
|
2.80
|
2.8
|
50
|
Cd
|
0.20
|
3.50
|
0.70
|
0.90
|
2.70
|
2.7
|
5
|
Cu
|
3.40
|
92.8
|
29.1
|
30.9
|
1.20
|
1.2
|
2000
|
Mo
|
0.30
|
21.4
|
4.20
|
6.60
|
2.00
|
2.0
|
|
Ni
|
9.90
|
105
|
24.8
|
26.0
|
3.10
|
3.1
|
70
|
Pb
|
2.10
|
44.7
|
13.4
|
11.7
|
1.80
|
1.8
|
10
|
Th
|
0.50
|
10.6
|
3.10
|
3.20
|
1.40
|
1.4
|
|
U
|
0.10
|
29.8
|
8.30
|
10.3
|
1.60
|
1
|
30
|
Zn
|
6.80
|
2505
|
348
|
692
|
3.20
|
3.2
|
3000
|
Table 2
a: Correlation coefficient matrix of heavy metals in surface water
|
As
|
Cr
|
Cd
|
Cu
|
Mo
|
Ni
|
Pb
|
Th
|
U
|
Zn
|
As
|
1.00
|
0.34
|
0.54
|
0.70**
|
0.46
|
0.21
|
0.64*
|
0.03
|
0.22
|
0.03
|
Cr
|
0.42
|
1.00
|
0.11
|
0.48
|
0.67*
|
0.93**
|
0.09
|
0.16
|
-0.08
|
0.04
|
Cd
|
0.54
|
0.11
|
1.00
|
0.76**
|
0.11
|
-0.01
|
0.57
|
0.49
|
0.32
|
0.46
|
Cu
|
0.70**
|
0.48
|
0.76**
|
1.00
|
0.48
|
0.40
|
0.75**
|
0.46
|
0.42
|
0.52*
|
Mo
|
0.46
|
0.67*
|
0.11
|
0.48
|
1.00
|
0.59
|
0.12
|
0.19
|
0.15
|
0.04
|
Ni
|
0.21
|
0.93**
|
-0.01
|
0.40
|
0.59
|
1.00
|
0.12
|
0.11
|
-0.06
|
0.08
|
Pb
|
0.64*
|
0.09
|
0.57
|
0.75**
|
0.12
|
0.12
|
1.00
|
0.21
|
0.33
|
0.37
|
Th
|
0.03
|
0.16
|
0.49
|
0.46
|
0.19
|
0.11
|
0.21
|
1.00
|
0.59*
|
0.33
|
U
|
0.22
|
-0.08
|
0.32
|
0.42
|
0.15
|
-0.06
|
0.33
|
0.59*
|
1.00
|
0.13
|
Zn
|
0.03
|
0.04
|
0.46
|
0.52*
|
0.04
|
0.08
|
0.37
|
0.33
|
0.13
|
1.00
|
*Level of significance = 0.05; **level of significance = 0.01 |
Table 2
b: Correlation coefficient matrix of heavy metals in groundwater
|
As
|
Cr
|
Cd
|
Cu
|
Mo
|
Ni
|
Pb
|
Th
|
U
|
Zn
|
As
|
1.00
|
0.10
|
0.79*
|
0.78**
|
0.94**
|
-0.04
|
0.27
|
-0.16
|
0.82**
|
-0.20
|
Cr
|
0.10
|
1.00
|
-0.12
|
-0.04
|
0.15
|
0.94**
|
-0.20
|
-0.15
|
-0.03
|
-0.17
|
Cd
|
0.79**
|
-0.12
|
1.00
|
0.58
|
0.74**
|
-0.15
|
0.17
|
-0.07
|
0.58
|
-0.06
|
Cu
|
0.78*
|
-0.04
|
0.58
|
1.00
|
0.76**
|
-0.13
|
0.12
|
0.12
|
0.81**
|
0.34
|
Mo
|
0.94*
|
0.15
|
0.74**
|
0.76**
|
1.00
|
-0.00
|
0.01
|
-0.28
|
0.89**
|
-0.21
|
Ni
|
-0.04
|
0.94**
|
-0.15
|
-0.13
|
-0.00
|
1.00
|
-0.22
|
-0.03
|
-0.23
|
-0.02
|
Pb
|
0.27
|
-0.20
|
0.17
|
0.12
|
0.01
|
-0.22
|
1.00
|
0.52*
|
-0.04
|
-0.05
|
Th
|
-0.16
|
-0.15
|
-0.07
|
0.12
|
-0.28
|
-0.03
|
0.52*
|
1.00
|
-0.28
|
0.43
|
U
|
0.82**
|
-0.03
|
0.58
|
0.81*
|
0.89**
|
-0.23
|
-0.04
|
-0.28
|
1.00
|
-0.16
|
Zn
|
-0.20
|
-0.17
|
-0.06
|
0.34
|
-0.21
|
-0.02
|
-0.05
|
0.43
|
-0.16
|
1.00
|
*Level of significance = 0.05; **level of significance = 0.01 |
Table 3
a: loading for varimax rotated factor matrix explaining 86.29% of the total variance for surface water
Parameters
|
VF1
|
VF2
|
VF3
|
VF4
|
As
|
0.719
|
0.036
|
-0.567
|
-0.300
|
Cr
|
0.575
|
0.769
|
0.125
|
0.098
|
Cd
|
0.731
|
-0.456
|
-0.114
|
0.126
|
Cu
|
0.971
|
-0.098
|
-0.085
|
0.080
|
Mo
|
0.590
|
0.568
|
0.100
|
-0.234
|
Ni
|
0.505
|
0.769
|
0.168
|
0.156
|
Pb
|
0.716
|
-0.334
|
-0.397
|
0.024
|
Th
|
0.535
|
-0.309
|
0.691
|
-0.100
|
U
|
0.458
|
-0.437
|
0.406
|
-0.537
|
Zn
|
0.466
|
-0.343
|
0.187
|
0.710
|
Eigenvalue
|
4.154
|
2.240
|
1.231
|
1.004
|
Loading%
|
41.544
|
22.398
|
12.308
|
10.043
|
Cumulative%
|
41.544
|
63.942
|
76.250
|
86.293
|
Table 3b: loading for varimax rotated factor matrix explaining 91.65 % of the total variance for groundwater.
Parameters
|
VF1
|
VF2
|
VF3
|
VF4
|
As
|
0.967
|
0.066
|
0.098
|
0.184
|
Cr
|
-0.012
|
0.865
|
0.471
|
0.110
|
Cd
|
0.814
|
-0.107
|
0.021
|
0.093
|
Cu
|
0.844
|
-0.196
|
0.337
|
-0.306
|
Mo
|
0.963
|
0.200
|
-0.003
|
-0.001
|
Ni
|
-0.164
|
0.799
|
0.562
|
0.052
|
Pb
|
0.133
|
-0.520
|
0.331
|
0.720
|
Th
|
-0.201
|
-0.572
|
0.684
|
0.164
|
U
|
0.920
|
0.045
|
-0.145
|
-0.144
|
Zn
|
-0.126
|
-0.410
|
0.548
|
-0.674
|
Eigenvalue
|
4.185
|
2.248
|
1.559
|
1.172
|
Loading%
|
41.852
|
22.480
|
15.594
|
11.723
|
Cumulative%
|
41.852
|
64.333
|
79.927
|
91.650
|
Principle Component Analysis
The varimax method with kaiser normalization was utilized for obtaining principal components. The related effect of the PCA established on factor analysis of the correlated chemical components for surface and groundwater are shown in tables (3a, 3b). Four constituents of PCA analysis showed 86.29% of the variance in the surface water data set of the study area. The eigenvectors classified the 10 heavy metals into four groups. The first constituent (VF1) is loaded with arsenic, cadmium, copper, and lead; the second constituent (VF2) is loaded with chromium and nickel, while the third constituent (VF3) thorium and fourth constituent (VF4) were not significant. Whereas, for groundwater data set the four constituents of PCA analysis showed 91.65% of the variance for 10 heavy metals into four groups. The first constituent (VF1) is loaded with major elements As, Cd, Cu, Mo, and U; the second constituent (VF2) is loaded with As, Cr, and Ni; the third component is loaded with As and Th; while the fourth constituent is loaded with Pb only.
Cluster Analysis
Cluster Analysis (CA) is one of the cluster-based statistical methods to classify different clusters based on their characteristic similarity to evaluate the surface water quality. Hierarchical agglomerative clustering is the most collective approach that delivers spontaneous comparison associations between anyone sample and the entire data set and delivers visual outlines of the clustering process and it is usually shown by a dendrogram (Vega et al., 1998; Singh et al., 2005; Tabachnick and Fidell, 1996; Shrestha and Kazama, 2007; Tokatlı et al., 2013; Tokatlı, 2014b).
Dendrogram obtained for surface water (Fig. 2) displayed five clusters with Cd, Cu, Ni (Cluster I), Cu, Ni, As (Cluster II), Ni, As, Pb (Cluster III), As, Pb, Zn (Cluster IV), Pb, Zn, Th, U, Cr (Cluster V). Cluster I and II specify the related activity of factor 1; Cluster IV and V represent the same activity of factors 3, 4 obtained by factor analysis. The subsequent multielement factors were separated into factors with strong anthropogenic influence. Whereas, Cluster III signifies the collective activity of factor 1 and factor 2. Correspondingly, for groundwater, the dendrogram obtained (Fig. 3) also showed three clusters with As, Mo, Cd (Cluster I), Mo, Cd, Cu, U (Cluster II), Cd, Cu, U, Pb, Th, Cr, Ni, Zn (Cluster III). This clustering points to collective causes of the natural method of degeneration of soil parts primarily carbonates. Cluster I and Cluster III resemble similar activity when compared to factor analysis components wherein Cr, N, Th, Pb played the dominating heavy metals. Therefore, the dominant source may be attributed to the drilling activities with backwater waste and partially from surrounding agriculture activity.