STUDY OF SEASONAL VARIATION OF ARSENIC CONCENTRATION IN GROUNDWATER IN GHAZIPUR DISTRICT OF UTTAR PRADESH

It was reported a clear temporal and seasonal variability of as concentrations in different water samples of Ghazipur district of eastern U. P. During post monsoon season as concentration decreases in Samples. A definite relationship exists between the behavior of arsenic and rainfall intensity. Groundwater quality depends on the composition of recharging water, the mineralogy and reactivity of the geological formations in aquifers, anthropogenic activities and environmental conditions that may affect the geochemical mobility of certain constituents. Arsenic concentrations in groundwater of the Kathmandu Valley show a wide range and some of groundwater sources investigated were found to be in elevated levels in some parts of the valley could be due to the nature of the sediments there. The high degree of spatial variability in groundwater quality over short distances indicates that groundwater movement has been limited and is poorly mixed. The higher concentration of arsenic under reduced groundwater environment may be due to Fe/Mn oxides and direct reduction of As(V) into As(III). After an initial increase, arsenic concentration often decreases again as a function of time below water table due to sulfide precipitation, whereas it increases with increasing sulfate concentrations above water table. Under moderately reduced environment (0 to 100 mV), arsenic solubility seemed to be controlled by the dissolution of Fe ox hydroxides. But at highly reduced condition, e.g., at −250 mV, arsenic chemistry is dominated by the formation of insoluble sulfides FeAsS, As, As2S3 attenuating concentration of arsenic in the groundwater.