The data is segregated into pre and post monsoon seasons based on date of collection of samples and these results are listed in Table 2 and Table 3 respectively.
Table 2
Chemical Analysis of water samples collected during pre-monsoon season
S.N.
|
S_No
|
Village
|
DMV_Code
|
LAT
|
LONG
|
SourceType
|
pH
|
EC
|
TDS
|
Ca + 2
|
Mg + 2
|
Na+
|
K+
|
TH
|
CO3− 2
|
HCO3−
|
Cl-
|
SO4-2
|
NO3-
|
F-
|
1
|
RP_01
|
Dubbaka
|
2320014
|
17.31
|
79.14
|
BW
|
7.1
|
3600
|
2304
|
110
|
65
|
198
|
2.0
|
543
|
0
|
108
|
621
|
87
|
28
|
4.02
|
2
|
RP_02
|
Dubbaka
|
2320014
|
17.32
|
79.14
|
BW
|
7.9
|
3800
|
2432
|
96
|
53
|
182
|
1.0
|
457
|
12
|
96
|
542
|
55
|
28
|
4.01
|
3
|
RP_03
|
Munipampula
|
2320004
|
17.32
|
79.15
|
TANK
|
8.2
|
2200
|
1408
|
74
|
40
|
176
|
3.0
|
351
|
9
|
66
|
437
|
11
|
14
|
2.23
|
4
|
RP_04
|
Munipampula
|
2320004
|
17.32
|
79.17
|
DW
|
7.8
|
2300
|
1472
|
88
|
44
|
161
|
4.0
|
401
|
12
|
54
|
486
|
44
|
13
|
1.60
|
5
|
RP_05
|
Palliwada
|
2320005
|
17.35
|
79.17
|
RIVER
|
7.9
|
2800
|
1792
|
112
|
28
|
242
|
2.0
|
395
|
9
|
102
|
547
|
16
|
11
|
2.22
|
6
|
RP_06
|
Palliwada
|
2320005
|
17.33
|
79.17
|
BW(HP)
|
7.1
|
2000
|
1280
|
110
|
26
|
99
|
4.0
|
382
|
0
|
90
|
305
|
42
|
36
|
0.94
|
7
|
RP_07
|
Bachuppala
|
2320006
|
17.34
|
79.21
|
DW
|
7.3
|
2500
|
1600
|
163
|
38
|
168
|
1.0
|
563
|
0
|
84
|
479
|
36
|
74
|
0.88
|
8
|
RP_08
|
Suraram
|
2320007
|
17.35
|
79.23
|
DW
|
7.8
|
3100
|
1984
|
74
|
48
|
176
|
2.0
|
382
|
6
|
126
|
381
|
27
|
22
|
1.62
|
9
|
RP_09
|
B.Thurkapalle
|
2320008
|
17.36
|
79.23
|
BW(HP)
|
7.3
|
4400
|
2816
|
99
|
52
|
231
|
6.0
|
460
|
0
|
144
|
546
|
46
|
150
|
2.50
|
10
|
RP_10
|
Peddabaigudem
|
2320010
|
17.34
|
79.23
|
BW
|
7.2
|
2700
|
1728
|
122
|
66
|
134
|
5.0
|
575
|
0
|
114
|
465
|
27
|
27
|
1.10
|
11
|
RP_11
|
Yennaram
|
2320010
|
17.32
|
79.21
|
DW
|
7.7
|
1200
|
768
|
118
|
74
|
268
|
4.0
|
601
|
0
|
96
|
802
|
15
|
19
|
1.95
|
12
|
RP_12
|
Kakkireni
|
2320011
|
17.32
|
79.21
|
BW
|
7.0
|
3500
|
2240
|
143
|
76
|
221
|
2.0
|
669
|
0
|
120
|
781
|
7
|
25
|
1.23
|
13
|
RP_13
|
Kakkireni
|
2320011
|
17.30
|
79.20
|
BW
|
7.0
|
2200
|
1408
|
112
|
16
|
176
|
8.0
|
348
|
0
|
72
|
458
|
17
|
31
|
0.58
|
14
|
RP_14
|
Iskilla
|
2320013
|
17.29
|
79.05
|
BW
|
7.1
|
1300
|
832
|
41
|
16
|
65
|
4.0
|
169
|
9
|
54
|
138
|
19
|
14
|
3.18
|
15
|
RP_15
|
Iskilla
|
2320013
|
17.29
|
79.14
|
BW
|
7.6
|
700
|
448
|
116
|
42
|
13
|
6.0
|
461
|
0
|
126
|
186
|
65
|
21
|
1.45
|
16
|
RP_16
|
Janampalli
|
2320021
|
17.29
|
79.12
|
BW
|
7.3
|
800
|
512
|
147
|
57
|
12
|
2.0
|
600
|
0
|
232
|
172
|
77
|
70
|
1.03
|
17
|
RP_17
|
Neernemla
|
2320015
|
17.32
|
79.09
|
DW
|
7.5
|
3300
|
2112
|
161
|
134
|
38
|
2.0
|
952
|
0
|
168
|
501
|
92
|
73
|
0.82
|
18
|
RP_18
|
Shobhanadripur
|
2320002
|
17.35
|
79.10
|
DW
|
7.6
|
3600
|
2304
|
121
|
48
|
186
|
4.0
|
499
|
33
|
78
|
546
|
17
|
41
|
1.49
|
19
|
RP_19
|
Laxmapur
|
2320003
|
17.35
|
79.11
|
DW
|
7.2
|
5700
|
3648
|
186
|
76
|
221
|
2.0
|
777
|
0
|
60
|
861
|
36
|
25
|
0.85
|
20
|
RP_20
|
Laxmapur
|
2320003
|
17.34
|
79.10
|
BW
|
7.2
|
3100
|
1984
|
184
|
26
|
186
|
1.0
|
565
|
0
|
54
|
650
|
32
|
47
|
0.44
|
21
|
RP_21
|
Neernemla
|
2320015
|
17.31
|
79.09
|
DW
|
7.4
|
4800
|
3072
|
161
|
28
|
198
|
8.0
|
517
|
0
|
121
|
456
|
102
|
36
|
0.76
|
22
|
RP_22
|
Kommaigudem
|
2320020
|
17.27
|
79.09
|
BW(HP)
|
7.2
|
2100
|
1344
|
116
|
65
|
242
|
4.0
|
558
|
0
|
84
|
602
|
35
|
169
|
1.34
|
23
|
RP_23
|
Ramannapet
|
2320020
|
17.30
|
79.10
|
BW
|
7.7
|
1500
|
960
|
47
|
19
|
162
|
2.0
|
195
|
9
|
72
|
320
|
8
|
54
|
2.32
|
24
|
RP_24
|
Bogaram
|
2320017
|
17.30
|
79.08
|
BW
|
7.2
|
900
|
576
|
86
|
21
|
14
|
1.0
|
302
|
0
|
66
|
110
|
88
|
26
|
0.96
|
25
|
RP_25
|
Bogaram
|
2320017
|
17.30
|
79.07
|
BW(HP)
|
7.5
|
600
|
384
|
39
|
5
|
12
|
3.0
|
118
|
0
|
66
|
32
|
46
|
8
|
0.94
|
26
|
RP_26
|
Bogaram
|
2320017
|
17.31
|
79.07
|
BW
|
8.7
|
1500
|
960
|
55
|
14
|
102
|
4.0
|
195
|
9
|
66
|
256
|
15
|
19
|
1.60
|
27
|
RP_27
|
Nidanpalli
|
2320016
|
17.32
|
79.08
|
BW
|
7.3
|
3200
|
2048
|
129
|
56
|
198
|
6.0
|
551
|
0
|
90
|
561
|
23
|
29
|
2.21
|
28
|
RP_28
|
Thummalagudem
|
2320001
|
17.34
|
79.05
|
TANK
|
8.5
|
2100
|
1344
|
49
|
42
|
176
|
2.0
|
293
|
6
|
78
|
462
|
10
|
14
|
1.53
|
29
|
RP_29
|
Thummalagudem
|
2320001
|
17.33
|
79.05
|
DW
|
7.2
|
1900
|
1216
|
112
|
13
|
145
|
1.0
|
332
|
0
|
84
|
376
|
35
|
13
|
0.72
|
30
|
RP_30
|
Yellanki
|
2320018
|
17.30
|
79.04
|
DW
|
7.3
|
1600
|
1024
|
67
|
26
|
158
|
2.0
|
275
|
0
|
90
|
334
|
13
|
9
|
0.72
|
31
|
RP_31
|
Yellanki
|
2320018
|
17.30
|
79.02
|
BW
|
7.6
|
1000
|
640
|
51
|
9
|
86
|
4.0
|
164
|
6
|
102
|
146
|
17
|
25
|
1.04
|
32
|
RP_32
|
Siripuram
|
2320019
|
17.29
|
79.04
|
BW
|
7.2
|
1400
|
896
|
63
|
15
|
76
|
2.0
|
220
|
0
|
84
|
195
|
9
|
62
|
0.80
|
33
|
RP_33
|
Siripuram
|
2320017
|
17.29
|
79.08
|
BW
|
7.4
|
1600
|
1024
|
98
|
8
|
162
|
4.0
|
276
|
0
|
96
|
408
|
5
|
25
|
1.48
|
34
|
RP_34
|
Siripuram
|
2320019
|
17.27
|
79.06
|
BW
|
7.4
|
1100
|
704
|
41
|
24
|
22
|
6.0
|
200
|
0
|
60
|
99
|
14
|
42
|
5.67
|
35
|
RP_35
|
Thummalagudem
|
2320001
|
17.33
|
79.04
|
BW
|
8.8
|
2100
|
1344
|
74
|
28
|
162
|
2.0
|
300
|
24
|
78
|
352
|
15
|
15
|
1.54
|
36
|
RP_36
|
Uthatoor
|
2320012
|
17.28
|
79.17
|
BW
|
7.5
|
810
|
520
|
104
|
38
|
16
|
5.0
|
442
|
0
|
76
|
136
|
49
|
17
|
1.52
|
Table 3
Chemical analysis of water samples collected during post-monsoon season
S.N.
|
S_No
|
Village
|
DMV_Code
|
LAT
|
LONG
|
Type of Source
|
pH
|
EC
|
TDS
|
Ca + 2
|
Mg + 2
|
Na+
|
K+
|
TH
|
CO3− 2
|
HCO3−
|
Cl-
|
SO4-2
|
NO3-
|
F-
|
1
|
RP_01
|
Dubbaka
|
2320014
|
17.31
|
79.14
|
BW
|
7.5
|
2813
|
1800
|
114
|
76
|
156
|
2.0
|
597
|
0
|
156
|
506
|
78
|
31
|
2.89
|
2
|
RP_02
|
Dubbaka
|
2320014
|
17.32
|
79.14
|
BW
|
7.8
|
3072
|
1966
|
116
|
66
|
186
|
4.0
|
561
|
0
|
201
|
522
|
78
|
27
|
3.02
|
3
|
RP_03
|
Munipampula
|
2320004
|
17.32
|
79.15
|
TANK
|
8.1
|
1992
|
1275
|
68
|
45
|
181
|
2.0
|
355
|
13
|
162
|
378
|
59
|
16
|
1.86
|
4
|
RP_04
|
Munipampula
|
2320004
|
17.32
|
79.17
|
DW
|
7.7
|
2189
|
1401
|
76
|
56
|
176
|
6.0
|
420
|
0
|
98
|
346
|
176
|
31
|
2.22
|
5
|
RP_05
|
Palliwada
|
2320005
|
17.35
|
79.17
|
RIVER
|
7.7
|
2563
|
1640
|
102
|
22
|
221
|
2.0
|
345
|
0
|
77
|
288
|
182
|
39
|
1.95
|
6
|
RP_06
|
Palliwada
|
2320005
|
17.33
|
79.17
|
BW(HP)
|
6.9
|
1859
|
1190
|
86
|
42
|
102
|
4.0
|
388
|
0
|
77
|
342
|
88
|
44
|
1.48
|
7
|
RP_07
|
Bachuppala
|
2320006
|
17.34
|
79.21
|
DW
|
7.3
|
2203
|
1410
|
126
|
34
|
148
|
4.0
|
455
|
0
|
178
|
424
|
78
|
29
|
1.32
|
8
|
RP_08
|
Suraram
|
2320007
|
17.35
|
79.23
|
DW
|
7.8
|
2906
|
1860
|
86
|
40
|
167
|
2.0
|
379
|
0
|
99
|
258
|
182
|
110
|
1.58
|
9
|
RP_09
|
B.Thurkapalle
|
2320008
|
17.36
|
79.23
|
BW(HP)
|
7.2
|
3828
|
2450
|
98
|
41
|
201
|
6.0
|
413
|
0
|
221
|
456
|
78
|
9
|
1.81
|
10
|
RP_10
|
P. Gudem
|
2320010
|
17.34
|
79.23
|
BW
|
7.2
|
2516
|
1610
|
126
|
58
|
146
|
2.0
|
553
|
0
|
121
|
521
|
78
|
11
|
1.17
|
11
|
RP_11
|
Yennaram
|
2320010
|
17.32
|
79.21
|
DW
|
7.7
|
1063
|
680
|
102
|
67
|
232
|
1.0
|
530
|
0
|
98
|
568
|
59
|
18
|
0.78
|
12
|
RP_12
|
Kakkireni
|
2320011
|
17.32
|
79.21
|
BW
|
6.8
|
3313
|
2120
|
122
|
72
|
209
|
4.0
|
601
|
0
|
126
|
561
|
68
|
14
|
1.19
|
13
|
RP_13
|
Kakkireni
|
2320011
|
17.30
|
79.20
|
BW
|
7.0
|
2158
|
1381
|
106
|
22
|
168
|
6.0
|
355
|
12
|
186
|
352
|
78
|
12
|
1.02
|
14
|
RP_14
|
Iskilla
|
2320013
|
17.29
|
79.05
|
BW
|
7.5
|
1047
|
670
|
56
|
28
|
98
|
4.0
|
255
|
14
|
88
|
221
|
59
|
20
|
2.56
|
15
|
RP_15
|
Iskilla
|
2320013
|
17.29
|
79.14
|
BW
|
7.2
|
3344
|
2140
|
86
|
38
|
66
|
4.0
|
371
|
0
|
76
|
301
|
22
|
12
|
1.36
|
16
|
RP_16
|
Janampalli
|
2320021
|
17.29
|
79.12
|
BW
|
7.3
|
2156
|
1380
|
121
|
38
|
22
|
2.0
|
459
|
21
|
222
|
168
|
22
|
66
|
1.16
|
17
|
RP_17
|
Neernemla
|
2320015
|
17.32
|
79.09
|
DW
|
7.5
|
1231
|
788
|
146
|
77
|
52
|
6.0
|
681
|
0
|
88
|
482
|
69
|
62
|
1.82
|
18
|
RP_18
|
Shobhanadripuram
|
2320002
|
17.35
|
79.10
|
DW
|
7.1
|
559
|
358
|
119
|
44
|
178
|
4.0
|
478
|
0
|
82
|
492
|
66
|
37
|
0.99
|
19
|
RP_19
|
Laxmapur
|
2320003
|
17.35
|
79.11
|
DW
|
7.1
|
753
|
482
|
151
|
71
|
186
|
6.0
|
669
|
0
|
121
|
561
|
78
|
13
|
0.26
|
20
|
RP_20
|
Laxmapur
|
2320003
|
17.34
|
79.10
|
BW
|
7.3
|
3266
|
2090
|
144
|
22
|
171
|
4.0
|
450
|
0
|
128
|
501
|
78
|
46
|
1.33
|
21
|
RP_21
|
Neernemla
|
2320015
|
17.31
|
79.09
|
DW
|
7.1
|
3444
|
2204
|
148
|
26
|
201
|
6.0
|
477
|
0
|
256
|
421
|
78
|
68
|
2.24
|
22
|
RP_22
|
Kommaigudem
|
2320020
|
17.27
|
79.09
|
BW(HP)
|
7.1
|
3922
|
2510
|
94
|
46
|
228
|
2.0
|
424
|
0
|
151
|
501
|
61
|
120
|
0.83
|
23
|
RP_23
|
Ramannapet
|
2320020
|
17.30
|
79.10
|
BW
|
7.5
|
2828
|
1810
|
56
|
26
|
152
|
4.0
|
247
|
0
|
128
|
258
|
71
|
45
|
1.65
|
24
|
RP_24
|
Bogaram
|
2320017
|
17.30
|
79.08
|
BW
|
7.2
|
4047
|
2590
|
98
|
18
|
26
|
6.0
|
319
|
0
|
146
|
98
|
78
|
22
|
0.88
|
25
|
RP_25
|
Bogaram
|
2320017
|
17.30
|
79.07
|
BW(HP)
|
7.3
|
1938
|
1240
|
42
|
16
|
32
|
2.0
|
171
|
0
|
58
|
66
|
52
|
121
|
0.82
|
26
|
RP_26
|
Bogaram
|
2320017
|
17.31
|
79.07
|
BW
|
8.4
|
1219
|
780
|
66
|
18
|
121
|
4.0
|
239
|
26
|
52
|
248
|
68
|
56
|
1.18
|
27
|
RP_27
|
Nidanpalli
|
2320016
|
17.32
|
79.08
|
BW
|
7.2
|
775
|
496
|
108
|
69
|
178
|
6.0
|
554
|
0
|
168
|
478
|
77
|
17
|
2.02
|
28
|
RP_28
|
Thummalagudem
|
2320001
|
17.34
|
79.05
|
TANK
|
8.3
|
534
|
342
|
52
|
56
|
168
|
2.0
|
360
|
22
|
88
|
382
|
78
|
31
|
1.51
|
29
|
RP_29
|
Thummalagudem
|
2320001
|
17.33
|
79.05
|
DW
|
7.1
|
1525
|
976
|
108
|
18
|
152
|
6.0
|
344
|
0
|
88
|
346
|
46
|
46
|
0.68
|
30
|
RP_30
|
Yellanki
|
2320018
|
17.30
|
79.04
|
DW
|
7.2
|
763
|
488
|
68
|
33
|
144
|
2.0
|
306
|
0
|
76
|
301
|
68
|
8
|
0.56
|
31
|
RP_31
|
Yellanki
|
2320018
|
17.30
|
79.02
|
BW
|
7.5
|
531
|
340
|
69
|
12
|
99
|
6.0
|
222
|
0
|
98
|
156
|
74
|
41
|
1.37
|
32
|
RP_32
|
Siripuram
|
2320019
|
17.29
|
79.04
|
BW
|
7.2
|
1281
|
820
|
58
|
24
|
71
|
4.0
|
244
|
0
|
76
|
201
|
22
|
76
|
1.45
|
33
|
RP_33
|
Siripuram
|
2320017
|
17.29
|
79.08
|
BW
|
7.4
|
3094
|
1980
|
79
|
18
|
156
|
4.0
|
271
|
0
|
72
|
358
|
68
|
46
|
2.24
|
34
|
RP_34
|
Siripuram
|
2320019
|
17.27
|
79.06
|
BW
|
7.3
|
2047
|
1310
|
38
|
26
|
28
|
2.0
|
202
|
0
|
66
|
132
|
22
|
9
|
4.56
|
35
|
RP_35
|
Thummalagudem
|
2320001
|
17.33
|
79.04
|
BW
|
8.2
|
1733
|
1109
|
78
|
56
|
158
|
6.0
|
425
|
18
|
129
|
358
|
68
|
12
|
2.24
|
36
|
RP_36
|
Uthatoor
|
2320012
|
17.28
|
79.17
|
BW
|
7.5
|
801
|
512
|
103
|
40
|
14
|
3.0
|
438
|
0
|
72
|
125
|
42
|
10
|
1.51
|
Fluoride
As per WHO and BIS guidelines, Allowable fluoride concentrations in potable waters is 1.5 mg/l. Consumption of high fluoride water can cause dental, mild skeletal, and crippling skeletal fluorosis (WHO; 2004). Fluoride in the water ranged from 0.30 to 3.00 mg/Lin the study area with an average of 1.42 mg/L was found. An average value of fluoride for all the sources is calculated for each habitation. From the collected data, the fluoride distribution maps were prepared using Spatial Analyst Tools (SAT)adopting Inverse Distance Weightage (IDW) method. Based on fluoride content in drinking water, the map is divided into three zones. That are Desirable (< 1.00 mg/L), Permissible (1.50-3.00 mg/L) and Non Potable (> 3.00 mg/L).
Figures 4 and 5 shows spatial fluoride distribution of the study area based on the collected water samples in pre and post monsoon seasons respectively. The elevated level (3–5 mg/L) of fluoride was observed at isolated places like in Dubbaka and Siripuram villages in central and south region of the Mandal. The people from these villages are at risk of dental/skeletal fluorosis.
Even, Ramannapet, Kommaigudem and Nidanpalli showed marginally high concentration of fluoride (1.5-3.0 mg/L). From Figs. 4 and 5, the spatial distribution of fluoride is lower during post-monsoon in some places when compared with pre monsoon collections. The dilution of fluoride with recharged rain water might be the reason. The fluoride concentration in groundwater can be diluted with surface water and its infiltration into downstream.
The fluoride content in groundwater varied in the study area due to the accessibility of fluorine-bearing minerals to the circulating water, the leaching and weathering activities. The fluoride concentration is more in shallow or moderately weathered Pediplains, Alkali Feldspar Granite, and Grey Biotite Granite which located in western part and around the mandal. Even, high concentration of fluoride was observed at isolated places in granite and dolerite, the west side of the mandal. Fluoride in the exogenic cycle of the fluorosis belt is almost contributed by the granitic and pegmatitic rocks. Above discussed fluoride bearing minerals of these rocks are the acid soluble minerals such as fluorite, fluorapatite, hornblende, mica, epidote etc. These minerals are responsible for high concentration of fluoride in natural waters, as they release fluoride under normal temperature pressure conditions. Furthermore, pH of water increases the releasing of fluorides from fluoride-bearing minerals during the weathering processes within the aquifers (Saxena and Ahmed 2001).
The fluoride minerals are abundant in the granite and gneiss rocks present in the mandal. Hence, the concentration of fluoride in groundwater is the highest in those villages present on the northern and southern parts and in isolated patches of the study area. The distribution of fluoride in groundwater depends on the amount of fluoride in the rocks or soils, the contact time of the water with the rocks, temperature, rainfall, vegetation and oxidation and reduction reactions. The percolating water dissolves the salts from soils, the fluoride concentration of groundwater may be higher than that during dry periods. The other factor is the amount of fluoride in the water depends on the degree of granitic rock weathering of the area (APSRAC, 1997).
Hydrogen Ion Concentration (pH)
pH is a measure of the relative acidity or alkalinity of a sample. It is equal to the negative logarithm of the hydrogen ion activity in moles per liter (–log aH+). The pH scale ranges from 1 to 14, with 1 being the most acidic and 14 being the most alkaline. Solutions with a pH less than 7.0 are typically classified as acidic; those greater than 7.0 as alkaline
The pH values in the Study area varied from 6.92 to 8.78 with an average of 7.51. pH of all the analyzed samples were within the permissible limiting value of 6.5–8.5 given by the BIS (2003).
Total Hardness
Water total hardness [TH] is caused by various dissolved salts of calcium, magnesium or iron and expressed as mg/l of CaCO¬3. The total hardness (TH) in ppm was determined by following equation (Todd 1980):
TH = 2:497 Ca2 + + 4:115Mg2+
According to Durfor and Becker’s (1964) classification of TH (i.e. 0–60, soft; 61–120, moderately hard; 121–180, hard; and > 180 very hard). In the present study area the hardness levels measured were in the range of 118 mg/l 8 to 952 mg/l with a mean value of 418 mg/l.
Electrical conductivity
Electrical Conductivity [EC] is one of the important indices of water quality, which gives the measure of the dissolved salts and salinity, the parameters imparting unpalatable taste to groundwater (Langengger, 1990). This has a significant impact on the user’s acceptance of such water resources (EdetAe, 1993). Conductivity is the measure of a solution’s ability to transfer electric current. The higher the conductivity of a solution, greater the potential to transfer electrical current. The conductance of a solution is dependent on three parameters: temperature (temperature increases the conductivity of a solution), nature of ions present, and quantity of ions present. Multivalent ions (i.e, those with valency greater than one) contribute more to conductivity than monovalent (valency one) charged ions. Most often, equipment for measuring conductivity gives results based on a temperature of 25°C. Such measurements can be adjusted to correct for other ambient temperatures (Peavy, et al., 1985). Because hydrogen ions (H+) and hydroxyl ions (OH–) exhibit higher conductance, due to their increased mobility, extreme pH levels are an important consideration when measuring conductance (Sawyer, et. al., 1994). The higher EC of the water samples is the result of ion exchange and dissolution of the aquifer material (Sanchez-Perez and Tremolieres, 2003).
The study area groundwater samples have EC in the range 600 to 5700 with an average of 2348 µS/cm. The maximum limit of EC in drinking water is prescribed as 1,500 µs/cm as per WHO standard. About half of the samples collected showed EC values more than permissible limit. EC distribution is found to be similar to that of Cl-, SO42-, HCO3- and K + distribution patterns, indicating it is positively correlated with these ions.
Total dissolved Solids (TDS)
TDS refers to the total dissolved solids present in the water. Measurement of conductivity is often used as an indirect method of estimating the dissolved solids content of a solution. (Chapra, 1997) reports a relationship between total dissolved solids and conductivity.
TDS (mg/L) = 0.64 x Conductivity (µmhos/cm)
As per the (BIS, 2003) specification for drinking water, 500 mg/l is treated as desired limit and 2000 mg/l of TDS is treated as maximum permissible limit. Higher concentrations of TDS decrease the palatability and may cause gastro-intestinal irritation in human and may also have laxative effect particularly upon transits. It is a well-known fact that the recharging water during its downward movement through the zone of aeration dissolves mineral matter thus enriching itself in total dissolved solids. This dissolution continues even in the zone of saturation due to rock-water interaction during the residence time of groundwater in the host rock. The enrichment of TDS is also governed by evaporation of water. In this study area all the samples have TDS between 384 and 3648 mg/l with an average value of 1503 mg/l.
Permeability Index (PI)
The Permeability Index (PI) values also depicts suitability of groundwater for irrigation purposes, since long-term use of irrigation water can affect the soil permeability, influenced by the Na+, Ca2+, Mg2+ and HCO3−contents of the soil. The PI can be expressed as
=The concentrations are reported in meq/l. (Doneen, 1964) developed a criterion for assessing the suitability of water for irrigation based on PI, where waters can be classified as classes I, II, and III. The PI of the area varied from 53.81 to 122.32 and the average value is 72.10.
Piper Classification:
The trilinear diagrams of Piper are very useful in determining chemical relationships in groundwater in more definite terms than is possible with other plotting methods (Piper, 1953). Piper’s trilinear diagram method is used to classify the groundwater, based on basic geochemical characters of the constituent ionic concentrations. The chemical data of the groundwater samples collected from the study area are plotted in the Piper’s diagram (Fig. 6). The chemical subdivisions 1, 2, 3, 4, 5, 6, 7, 8 and 9 indicate that the alkaline (Ca + and Mg+) and strong acids mainly dominate the chemical characteristic of the groundwater. Based on Piper classification all samples are fall in the IV category (Strong acids exceeds weak acids) in pre and post-monsoon periods.
US salinity Laboratory diagram:
The US Salinity Laboratory Staff, 1954) proposed a diagram for studying the suitability of groundwater for irrigation purposes by using the SAR values on vertical axis and electrical conductivity on horizontal axis.
The diagram is divided into four distinct classifications both horizontally and vertically. On horizontal axis the salinity hazard classification is divided into low salinity (C1), medium salinity (C2), high salinity (C3) and very high salinity (C4). Likewise on vertical axis sodium hazard classification is divided into low sodium water (S1), medium sodium water (S2), high sodium water (S3) and very high sodium water (S4). Figure 7 shows Richards Diagrams classification of irrigation water during pre and post monsoon period respectively.
It is clear from the Fig. 7 that the groundwater samples of the study area out of 36samples fall under Majority of samples are fall in the S1C3 and S2C4 category in pre and post-monsoon periods.
Recommendations & observations
It is important to educate every citizen about the fluoride toxicity and the necessity of avoiding fluoride consumption. The intake of fluoride above the permissible limit in drinking water is the major reason for fluorosis disease in some parts of the study area. It is encouraged that Taking safe drinking water with sufficient dietary food in order to avoid fluorosis disease. It should be identified the fluoride affected areas with the help of scientific mapping and watersheds are proposed in the area. It is important to look for holistic and people-centred approaches for water management.
The occurrence groundwater in the study area is completely controlled by rainfall and canal whereas the quality of the water controlled by the terrain features like landforms, lithology, soil, drainage, topography, etc. The information provided in the groundwater prospect zones helps in identifying the areas suitable for artificial recharge. Tremendous pressure on groundwater for domestic, agriculture and industrial uses results in pollution of groundwater resources. In the future, the limited resources will not be able to meet out the water demand qualitatively and quantitatively for next generation. With scientific guidelines, watersheds to be constructed on Fast Track basis. Groundwater management and artificial recharge structures will be helpful for recharging of groundwater to make the existing bore wells and dug wells sustainable.
Table 4. Number of Samples falling in different Areas of Diamond shaped field of Piper Diagram