Studies on the Pollution of the Kalinadi by Industrial Wastes near Mansurpur Part 2: Biological Index of Pollution and Biological Characteristics of the River

From the biological data presented here it is difficult to define any species of fish as an indicator of pollution in the strict sense. Nevertheless, the following generalizations are possible.

• - Species as Wallago attu, Clarias batrachus, Heteropneustes fossilis, Ophiocephalus striatus and Oph. punctatus occur in good number in the polluted stretch and seem to be tolerant species.
• - The species as Esomus danrica, Labeo rohita, Labeo gonius, L. bata, Catla catla, Cirrhina mrigala, Barbus chagunio, Barbus spec., Notopterus notopterus and Mugil corsula are most sensitive and disappear first in the polluted stretch.
• - The species as Barilius bola, B. bendelisis, Nemacheilus latius, Notopterus chitala, Collichrous bimaculatus, and Nandus nandus are moderately sensitive.
• - It appears that the main damage is caused to carp and feather-back fishes. The whole stretch of heavy pollution is almost devoid of carp and featherback.

The following important conclusions can be drawn from the distribution of plankton and bottom organisms:

• - The higher number of protozoans, chironomids, maggots and the decrease in the number of mollusca can be considered as the indicator of pollution, because of their abundance in polluted zones.
• - Chlorella, Lyngbya, Gyrosigma and Euglena (algae), Viviparius (mollusc) and Bosmina (crustacea) are very sensitive to pollution.
• - Oscillatoria, Pandorina, Anabaena, Nitzschia, Closterium (algae), Branchionus, Rotatoria (rotifers) and Naidium (annelid) are moderately sensitive.
• - Synedra, Spirogyra, Desmidium, Rivularia, Navicula, Fragillaria Phacus, Arcella and Vorticella are fairly tolerant forms.
• The stretch studied has been subdivided into five zones with characteristic features:
• - The Oligosaprobic Zone - characterized by a sufficient oxygen saturation, low B. O. D. and C. O. D., with a good fauna and flora.
• - The Polysaprobic Zone - with low oxygen saturation, high B. O. D. and C. O. D. and hydrogen sulphides with a restricted fauna and flora.
• - The α-Mesosaprobic zone - with moderate oxygen saturation, moderate B. O. D. and C. O. D. traces of hydrogen sulphide with the improvement of the fauna and flora.
• - The β-Mesosaprobic Zone - with fair oxygen saturation, low B. O. D. and C. O. D., with the reappearence of fauna and flora.
• - The Oligosaprobic Zone - similar to the zone of low pollution in all characteristics.