Abstract:
Arsenic IS of significant environment concern In much of the world
because of its concentration in underground water, which may be
originated from the parent materials of soils, as soil is known as to act as
a majOr sink of arsenic in its contaminated ground water belt. In the
present study. some of the important cations (Iron, Manganese,
Aluminum, Sodium and Magnesium), anions (Nitrate, Phosphate,
Chloride and Carbonate), soil pH, Ehand soil texture from surface to 90ft
depths of some selected spots were measured. Arsenic contents of water
of 90ft depth of these spots were also measured. The main purpose of this
study was to evaluate whether these properties and compositions of soil
have any influence on the concentration of arsenic in underground water.
It was found that the arsenic content of underground water has a good
relation with the concentration of soil, Iron, Manganese, Aluminium,
Magnesium, Phosphate and carbonates. Percentage of clay content was
found as an important parameter for the adsorption of arsenic and the
mentioned ions on soil, which have influences on the leaching of arsenic
to the underground water. The first level of underground water of our
study areas were found with in 80ft to 90ft depths. So soil compositions
and texture of their near about levels may have important influence on
the arsenic content of water, which accumulates through leaching from
the soil materials. It was observed that underground water sample of
Savar spot showed the lowest concentration of arsenic, 0.0104ppm and
the water sample of Kholapara spot showed highest concentration of
arsenic, O.0752ppm. Arsenic contents in underground water of Singair,
Kiting Char and Vlail were found 0.0689ppm, O.035ppmand 0.0165 ppm
respectively. It was observed that for the soil samples of Savar, Kiting
Char and Vlail spots, near about the first level of underground water have
higher percentages of clay contents. Iron, Manganese, Aluminium and
Carbonate contents were also higher in these samples. Phosphate and
••
Magnesium contents were found lower in these samples. Arsenic
contents in water of thcse spots were found with in the safe level, below
0.05 ppm. Much higher contents of arsenic in underground water were
found in Singair and Kholapara spots, where percentage of clay and
concentration of soil Iron, Manganese, Aluminium and Carbonates were
found lower near about the first levels of the underground water layer.
But phosphate and magnesium contents were found higher in these
samples. So it may be assumed that greater contents of Iron, Manganese,
Aluminium, Carbonate and Clay in soil influence on the higher
adsorption of arsenic in soil and lower leaching of arsenic to water.
Where as greater contents of magnesium and phosphates in soil influence
lower adsorption of arsenic in soil and higher leaching to underground
water.
