ORGANIC CARBON IN THE SEDIMENTS OF THE LOWER REACHES OF PERIAR RIVER

Abstract

Sediments are indicators of the quality of water overlying them and hence, useful in the
assessment of environmental pollution. Temporal and spatial variations in sediment
characteristics and organic carbon content from 9 stations in the lower reaches of Periyar
river an area in Cochin Backwater which is polluted from different sources· were studied
for one year during 1981. Variations in colour and texture of sediments were brought about
by changes in the grain size and state of oxidation of organic matter. The colour of the
sediment varied from greyish black at stations 1 and 2, brownish at station 3, black at
stations 4 to 8 and reddish at station 9.
Organic carbon and sediment texture showed a direct relationship at all stations except
at station 9 where organic carbon content showed an irregular pattern. Overall range of
organic carbon content was between 1.19 and 29.6 mg.g-1• The mean organic carbon of the
stations ranged between 6.8 mg.g-1 (station 5) and 20.8 mg.g-1 (station 9). On the whole
temporal variations were considerable with high values at station 9 and low values at station
5. Fluctuations were more at stations 6,7 and 8.