Hydrochemical characteristics and seasonal variations in groundwater quality of an alluvial aquifer in parts of Central Ganga Plain, Western Uttar Pradesh, India

The present study was undertaken to assess
major ion chemistry of groundwater in parts of the Central
Ganga Plain and observe seasonal variations in its chemical
quality. Systematic sampling was carried out during
November 2005 and June 2006. The major ion chemistry of
groundwater shows large variations, so much so that at
times the meteoric signature seems to be completely
obliterated. In many samples the concentrations of SO4,
NO3 and F are above the permissible limit for human
consumption. The graphical treatment of major ion chemistry
helps in identifying four types of groundwater. All
possible ionic species such as NaCl, KCl, NaHCO3,
NaSO4, KNO3, NaNO3, CaHCO3, MgHCO3, MgSO4 are
likely to occur in groundwater system. The observed
chemical variations may be attributed to sediment water
interaction, ion exchange, dissolution mechanisms and
anthropogenic influences such as application of fertilizers
and effluents from sugar factories and paper mills. A
general increase in TDS is observed in samples during June
2006. The increase in salinity is attributed to evaporation
from water table, irrigation return flows, anthropogenic
activities and below average rainfall in 2005 and 2006.