3. Materials and MethodFifty ground

3. Materials and Method
Fifty groundwater samples were collected during premonsoon
and postmonsoon
seasons in
a grid pattern at five selected zones and five samples each at northern and southern part of the
river is collected at a distance of about 500 m, 1000 m, 1500 m, 2000 m and 2500 m from
River Noyyal in order to study the level of penetration of polluted water into the aquifer
system (Figure.1). Samples were collected during July 2008 (premonsoon)
; December 2008
(postmonsoon)
; July’ 2009 (premonsoon)
and December 2009 (postmonsoon).
Surface
water samples were collected using Aqua trap water sampler. For collection, preservation and
analysis of the samples, the standard methods (APHA, 1995) were followed. Electrical
conductivity and pH of water samples were measured in the field immediately after the
collection of the samples using portable pH and electrical conductivity meters. Na + and K +were measured by using a flame photometer. Total dissolved solids (TDS) were measured by
evaporation and calculation methods (Hem, 1991). Ca 2+ and Mg 2+ were determined
titrimetrically using standard EDTA. Chloride was estimated by AgNO3 titration. Sulphate
was analysed using the turbidimetric method (Clesceri et al. 1998). Nitrate was analysed
using UV–visible spectrophotometer (Rowell, 1994).