Geoscience Reference
In-Depth Information
2000
a: Maximum
b: Minimum
c: Average
1600
(a)
1200
(b)
(c)
800
400
0
1
2345
1
2345
1
2345
1. Pakhales
3. Sand Stone
2. Granite Gneisses
4. Alluvium
5. Clay
Fig. 3.
EC of bore well waters in different geological formations.
its suitability are more in groundwater of hard rock areas as compared to
sedimentary or recent. The more emphasis has been given for the detailed
chemical study of these bore wells water. Based on chemical composition of
bore well water and associated geological formations (Fig. 2), these ground-
waters have been studied. It is observed; more or less some relationship has
been observed in between geological formations and water types. The EC
is more in granite gneisses compared to recent and clay. The results are
presented in Fig. 3. This figure showed the changes in EC with geological
formations. Such changes are also found to be correlated in term of maxi-
mum, minimum and average values of EC. For examples, higher EC levels
are shown in granite gneisses against low in clay. The changes in bore well
water chemistry with depths have been studied. To make this study more
simple the bore wells are divided into two categories (1) shallow ( < 50 m
depth) and (2) deep ( > 50 m depth). The TDS of bore well waters and the
depths of bore wells have been examined and found to have a positive cor-
relation. In addition to this, those bore wells are located in granite gneisses
may have deeper depths and less discharge. The data showed that 86% bore
wells in hard rock areas may have deeper depths ( > 50 m). A fairly good
discharge ( > 20,000 l/h) has been shown in sedimentary formations.
Fluoride concentration varies from 1 to 2.5 mg/l, 25% samples of the
total have shown fluoride, which is more than permissible limit of drink-
ing water. 2 It is also indicated that the high F contents are observed in
Govindropet (sample No. 10) and Bhimla near sample No. 15. These loca-
tions are within the granite gneisses. However, the high fluorite (0.4-0.9%)
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