Seasonal and spatial distributions of nutrients
(NO
$_2$
-N, NO
$_3$
-N,
NH
$_4$
-N, PO
$_4$
-P,
SiO
$_4$
-Si, total nitrogen and total phosphorous) in relation
to some physico-chemical features (DO, BOD, TSS, TDS,
SO
$_4^{2-}$
and Cl
$^{-}$
) were studied for 31
different stations of Mahanadi river-estuarine system. Results of nutrient
concentrations exhibit pronounced seasonal variations and distribution pattern
indicating large inputs possibly from two major fertilizer plants, municipal
sewage from three major towns as well as agricultural runoff. The seasonal
nutrients variation (except SiO
$_4$
-Si) exhibits higher values
during monsoon season in unpolluted stations and the reverse trend for polluted
stations, which are related to agricultural runoff and regional anthropogenic
activities respectively. Silicate shows a well-defined pattern of distribution
with higher concentration during monsoon, which is slightly removed from the
estuarine water of Mahanadi during pre-monsoon season. High organic
contribution of nitrogen and phosphorus are well marked at Atharbanki creek
into the Mahanadi river estuarine system.
