Table 1: Statistical summary of major ions concentrations of groundwater for pre and post-rainfall seasons
Parameters
|
Pre-rainfall season
|
|
Post-rainfall season
|
|
|
Min
|
Max
|
Ave
|
SD
|
% of samples exceeding the limits
|
Min
|
Max
|
Ave
|
SD
|
% of samples exceeding the limits
|
BIS (2012) Acceptable limit
|
pH
|
6.70
|
8.10
|
7.30
|
0.27
|
--
|
6.80
|
8.0
|
7.24
|
0.26
|
--
|
6.5-8.5
|
EC (μS/cm)
|
314.06
|
5643.75
|
1947.97
|
1460.61
|
--
|
240.63
|
5401.56
|
1977.21
|
1456.30
|
--
|
750
|
TDS (mg/l)
|
201.0
|
3612.0
|
1246.70
|
934.79
|
84
|
154.0
|
3457.0
|
1265.42
|
937.78
|
78
|
500
|
Ca2+ (mg/l)
|
28.0
|
203.57
|
95.16
|
45.19
|
66
|
3.0
|
541.35
|
107.29
|
81.68
|
68
|
75
|
Mg2+ (mg/l)
|
7.40
|
127.44
|
56.53
|
32.48
|
42
|
7.63
|
193.81
|
67.17
|
43.46
|
54
|
50
|
Na+ (mg/l)
|
15.98
|
534.96
|
149.42
|
142.05
|
24
|
7.05
|
476.31
|
135.33
|
126.78
|
32
|
200
|
K+ (mg/l)
|
1.10
|
85.92
|
10.61
|
16.85
|
20
|
1.0
|
103.51
|
10.47
|
19.53
|
16
|
12
|
HCO3- (mg/l)
|
124.44
|
758.84
|
409.72
|
132.49
|
84
|
43.92
|
630.0
|
194.66
|
128.99
|
32
|
300
|
Cl- (mg/l)
|
7.81
|
1667.46
|
354.67
|
453.67
|
38
|
7.63
|
1089.20
|
256.69
|
274.13
|
38
|
250
|
SO4- (mg/l)
|
0.0
|
1533.03
|
162.21
|
296.92
|
24
|
5.18
|
1200.0
|
146.34
|
237.05
|
22
|
200
|
NO3- (mg/l)
|
0.09
|
897.28
|
123.65
|
151.45
|
62
|
0.0
|
606.10
|
120.30
|
133.10
|
64
|
45
|
F- (mg/l)
|
0.28
|
5.48
|
1.18
|
0.89
|
32
|
0.21
|
4.43
|
1.35
|
0.95
|
30
|
1.5
|
Table 2: Key parameters for computing the exposure risk of fluoride through ingestion and dermal pathways
Parameters
|
Unit
|
6-12 months
|
6-11 years
|
11-16 years
|
16-18 years
|
18-21 years
|
≥ 21 years
|
> 65 years
|
Ingestion pathway
|
|
|
|
|
|
|
|
|
Ingestion rate (IRw)
|
L/day
|
1
|
1.32
|
1.82
|
1.78
|
2.34
|
2.94
|
2.73
|
Exposure frequency (Efr)
|
Days/year
|
365
|
365
|
365
|
365
|
365
|
365
|
365
|
Exposure duration (ED)
|
Year
|
6
|
6
|
6
|
6
|
30
|
30
|
30
|
Body Weight (BW)
|
kg
|
9.1
|
29.3
|
54.2
|
67.6
|
67.6
|
78.8
|
80
|
Average time (ATr)
|
Days
|
2190
|
2190
|
2190
|
2190
|
10,950
|
10,950
|
10,950
|
Concentration of element (Cfw)
|
Mg/l
|
Present study
|
Dermal pathway
|
Unit
|
6-12 months
|
6-11 years
|
11-16 years
|
16-18 years
|
18-21 years
|
≥ 21 years
|
> 65 years
|
Skin surface area (SA)
|
cm2
|
4500
|
10,500
|
15,700
|
18,000
|
19,550
|
19,800
|
19,400
|
Exposure time (ET)
|
h/event
|
0.54
|
0.54
|
0.54
|
0.54
|
0.71
|
0.71
|
0.71
|
Exposure frequency (Efr)
|
Days/year
|
350
|
350
|
350
|
350
|
350
|
350
|
350
|
Exposure duration (ED)
|
Year
|
6
|
6
|
6
|
6
|
30
|
30
|
30
|
Conversion factor (CF)
|
L/cm3
|
0.001
|
0.001
|
0.001
|
0.001
|
0.001
|
0.001
|
0.001
|
Body weight (BW)
|
kg
|
9.1
|
29.3
|
54.2
|
67.6
|
67.6
|
78.8
|
80
|
Average time (ATr)
|
Days
|
2190
|
2190
|
2190
|
2190
|
2190
|
2190
|
2190
|
Skin adherence factor (Kp)
|
cm/h
|
0.001
|
0.001
|
0.001
|
0.001
|
0.001
|
0.001
|
0.001
|
Concentration of element (Cfw)
|
mg/l
|
Present study
|
Table 3: Different category of fluoride and nitrate concentration in groundwater for pre and post-rainfall seasons
Category
|
F- conc.
(mg/l)
|
Pre- rainfall
|
Post- rainfall
|
NO3-conc.
(mg/l)
|
Pre- rainfall
|
Post- rainfall
|
No. of Samples
|
% of Samples
|
No. of Samples
|
% of Samples
|
No. of Samples
|
% of Samples
|
No. of Samples
|
% of Samples
|
Category-1
|
F- ≤ 0.5
|
10
|
20
|
10
|
20
|
NO3- ≤ 45
|
19
|
38
|
18
|
36
|
Category-2
|
F- > 0.5 ≤ 1.5
|
24
|
48
|
22
|
44
|
NO3-> 45 ≤ 100
|
6
|
12
|
10
|
20
|
Category-3
|
F- >1.5
|
16
|
32
|
18
|
36
|
NO3- > 100
|
25
|
50
|
22
|
44
|
Table 4: Classification of the WQI scores for pre and post-rainfall seasons
WQI range
|
Type of water
|
Pre- rainfall (n=50)
|
Post- rainfall (n=50)
|
No. of samples
|
% of samples
|
No. of samples
|
% of samples
|
<50
|
Excellent water
|
12
|
24
|
14
|
28
|
>50-100
|
Good water
|
22
|
44
|
22
|
44
|
>100-200
|
Poor water
|
10
|
20
|
11
|
22
|
>200-300
|
Very poor water
|
06
|
12
|
03
|
06
|
>300
|
Unsuitable for drinking
|
Nil
|
Nil
|
Nil
|
Nil
|
Table 5: Principal component analysis for groundwater samples during pre and post-rainfall seasons
Parameters
|
Principal Component Analysis for groundwater samples
|
Pre- rainfall season
|
Post- rainfall seasons
|
PC1
|
PC2
|
PC3
|
PC1
|
PC2
|
PC3
|
PC4
|
pH
|
-0.346
|
-0.260
|
0.747
|
-0.063
|
-.073
|
0.111
|
0.909
|
EC (μS/cm)
|
0.918
|
0.217
|
-0.135
|
0.855
|
0.448
|
0.004
|
-0.110
|
TDS (mg/l)
|
0.918
|
0.217
|
-0.135
|
0.855
|
0.448
|
0.004
|
-0.110
|
Ca2+ (mg/l)
|
0.738
|
0.371
|
-0.366
|
0.472
|
0.720
|
-0.216
|
-0.171
|
Mg2+ (mg/l)
|
0.908
|
0.229
|
-0.085
|
0.722
|
0.560
|
0.037
|
-0.041
|
Na+ (mg/l)
|
0.924
|
0.035
|
0.194
|
0.918
|
0.195
|
0.180
|
0.103
|
K+ (mg/l)
|
0.637
|
-0.438
|
-0.277
|
0.749
|
-0.275
|
-0.261
|
0.049
|
HCO3- (mg/l)
|
0.623
|
0.040
|
0.134
|
-0.410
|
-0.273
|
0.595
|
-0.350
|
Cl- (mg/l)
|
0.799
|
0.344
|
-0.215
|
0.754
|
0.499
|
-0.195
|
-0.007
|
SO4- (mg/l)
|
0.845
|
-0.211
|
0.030
|
0.885
|
0.064
|
0.059
|
-0.031
|
NO3- (mg/l)
|
0.313
|
0.755
|
0.093
|
0.037
|
0.868
|
0.041
|
0.271
|
F- (mg/l)
|
0.210
|
0.154
|
0.852
|
0.202
|
0.164
|
0.827
|
0.300
|
Eigen value
|
6.32
|
1.75
|
1.66
|
5.19
|
2.68
|
1.25
|
1.19
|
% of Variance
|
48.60
|
13.48
|
12.77
|
39.89
|
20.59
|
9.59
|
9.23
|
Cumulative % of Variance
|
48.60
|
62.09
|
74.85
|
39.89
|
60.48
|
70.08
|
79.30
|
Table 6: Hazard Quotient (HQ) for Fluoride and Nitrate via ingestion (HQing) pathway for different age groups for pre and post-rainfall seasons
Age Group
|
Hazard Quotient (HQ) via Ingestion pathways for F-
|
Hazard Quotient (HQ) via Ingestion pathways for NO3-
|
Pre- rainfall (HQing) F-
|
Post- rainfall (HQing) F-
|
Pre- rainfall (HQing) NO3-
|
Post- rainfall (HQing) NO3-
|
Min
|
Max
|
Ave
|
SD
|
Min
|
Max
|
Ave
|
SD
|
Min
|
Max
|
Ave
|
SD
|
Min
|
Max
|
Ave
|
SD
|
6-12 months
|
0.51
|
10.04
|
2.17
|
1.64
|
0.37
|
8.10
|
2.47
|
1.74
|
0.00
|
61.62
|
8.49
|
10.40
|
0.00
|
41.62
|
8.26
|
9.14
|
6-11 years
|
0.21
|
4.11
|
0.88
|
0.67
|
0.15
|
3.32
|
1.07
|
0.71
|
0.00
|
25.26
|
3.48
|
4.26
|
0.00
|
17.06
|
3.33
|
3.74
|
11-16 years
|
0.15
|
3.06
|
0.66
|
0.50
|
0.11
|
2.47
|
0.75
|
0.53
|
0.00
|
18.83
|
2.59
|
3.17
|
0.00
|
12.72
|
2.52
|
2.79
|
18-18 years
|
0.12
|
2.40
|
0.52
|
0.39
|
0.08
|
1.94
|
0.59
|
0.41
|
0.00
|
14.76
|
2.03
|
2.49
|
0.00
|
9.97
|
1.97
|
2.19
|
18-21 years
|
0.16
|
3.16
|
0.68
|
0.51
|
0.11
|
2.55
|
0.77
|
0.54
|
0.00
|
19.41
|
2.67
|
3.27
|
0.00
|
13.11
|
2.60
|
2.87
|
>21 years
|
0.17
|
3.41
|
0.73
|
0.55
|
0.12
|
2.75
|
0.83
|
0.59
|
0.00
|
20.92
|
2.88
|
3.53
|
0.00
|
14.13
|
2.80
|
3.10
|
>65 years
|
0.16
|
3.11
|
0.67
|
0.51
|
0.11
|
2.51
|
0.76
|
0.54
|
0.00
|
19.13
|
2.63
|
3.23
|
0.00
|
12.92
|
2.56
|
2.83
|
Table 7: Hazard Quotient (HQ) for Fluoride and Nitrate via dermal (HQder) pathway for different age groups for pre and post-rainfall seasons
Age Group
|
Hazard Quotient (HQ) via Dermal pathways for F-
|
Hazard Quotient (HQ) via Dermal pathways for NO3-
|
Pre- rainfall (HQder) F-
|
Post- rainfall (HQder) F-
|
Pre- rainfall (HQder) NO3-
|
Post- rainfall (HQder) NO3-
|
Min
|
Max
|
Ave
|
SD
|
Min
|
Max
|
Ave
|
SD
|
Min
|
Max
|
Ave
|
SD
|
Min
|
Max
|
Ave
|
SD
|
|
6-12 months
|
0.00
|
0.04
|
0.00
|
0.007
|
0.00
|
0.03
|
0.01
|
0.007
|
0.00
|
0.26
|
0.03
|
0.04
|
0.00
|
0.17
|
0.03
|
0.03
|
|
6-11 years
|
0.00
|
0.03
|
0.00
|
0.005
|
0.00
|
0.02
|
0.00
|
0.005
|
0.00
|
0.19
|
0.02
|
0.03
|
0.00
|
0.13
|
0.02
|
0.02
|
|
11-16 years
|
0.00
|
0.02
|
0.00
|
0.004
|
0.00
|
0.02
|
0.00
|
0.004
|
0.00
|
0.15
|
0.02
|
0.02
|
0.00
|
0.10
|
0.02
|
0.02
|
|
18-18 years
|
0.00
|
0.02
|
0.00
|
0.003
|
0.00
|
0.01
|
0.00
|
0.004
|
0.00
|
0.14
|
0.01
|
0.02
|
0.00
|
0.09
|
0.02
|
0.02
|
|
18-21 years
|
0.13
|
2.53
|
0.54
|
0.41
|
0.09
|
2.04
|
0.62
|
0.44
|
0.00
|
15.55
|
2.14
|
2.62
|
0.00
|
10.50
|
2.08
|
2.30
|
|
>21 years
|
0.11
|
2.20
|
0.47
|
0.36
|
0.08
|
1.77
|
0.54
|
0.38
|
0.00
|
13.51
|
1.86
|
2.28
|
0.00
|
9.12
|
1.81
|
2.00
|
|
>65 years
|
0.10
|
2.12
|
0.45
|
0.34
|
0.08
|
1.71
|
0.52
|
0.36
|
0.00
|
13.04
|
1.79
|
2.20
|
0.00
|
8.80
|
1.74
|
1.93
|
|