Fluoride Toxicity in the Fluoride Endemic Villages of Gaya District, Bihar, India - Management of Natural Resources in a Changing Environment - page 265

Geology of the Study Area

Gaya district is located at 84.4° E to 85.5° E Longitude and 24.5° N to 25.1° N
Latitude and has total area of 487,607.83 km 2 . Greater part of Gaya district is occu-
pied by the Gangetic alluvium, but older rocks rise above its level, chiefl y in the
south and east. These rocks are mostly composed of foliated gneiss, a subdivision
of the Archean system which contains the oldest rocks of the earth's crust (O'malley
2007 ). The Gidhour hills lie across the southern boundary of Gaya, composed of
Dharwars, including micaceous and ferruginous schist so highly metamorphosed by
intrusive coarse pegmetitic granites that they yield mica. The north eastern part of
district is mainly quartzite and slate, and very barren because of lack of forests.
The south east corner of district is situated in the middle of rich mica belt.

Methodology

A total of 31 villages of Bodh Gaya, Manpur, Wazirganj, Belaganj, Amas and
Bankebazar blocks in Gaya district of Bihar were included in this study. Twenty
samples of drinking water were collected from each block, except Bankebazaar,
from where 23 samples were collected. Likewise 123 samples were collected and
analyzed for fl uoride and other physico-chemical parameters. The samples were
collected during the pre-and post-monsoon in pre-cleaned high density polypropylene
sample (1 L) bottles and stored at 4 °C before analysis. Fluoride (F) level was
measured by using Fluoride Ion selective electrode Orion 9690 BNWP with PCD
650 cyber scan portable meter. Commercially available ion strength adjusting buffer
i.e. ISA I was added to the samples before the estimation of fl uoride. Other physico-
chemical parameters were estimated according to APHA-AWWA-WPCF ( 1995 ).
Hardness and calcium were estimated with EDTA titrimetric methods. pH, conduc-
tivity, TDS and turbidity were measured by portable PCD 650 multi tester. Iron was
estimated with the Phenanthroline method. Moreover, 93 urine and blood samples
from different age groups including adult males, adult females and children (with
confi rmed dental fl uorosis) from F affected areas were also analyzed. Fifty-two
samples from Bodh Gaya block were also collected as controls for hematological and
biochemical analysis. The blood was collected in heparinized vials. The hemato-
logical analysis was done with the help of Automatic Hematolyzer (Sysmex KX-21).
Further plasma was separated for biochemical analysis. The reagents kits of ERBA
make were used for blood analysis. The levels of glucose and calcium were estimated
by using Blood Chemistry analyzer (Biotech BT-260 plus). The TT3, TT4, and TSH
levels were estimated by ELISA reader (ERBA Lisa scan EM). The health survey was
conducted with a pre-designed questionnaire. The F exposure dose was calculated
by the equation as was done by Viswanathan et al. ( 2009 ):

Exposure dose =× CWIBW /