Aspects of Water Pollution in Lake Naini Tal, U.P., India

Abstract

The paper discusses certain microbiological, biological, and chemical, aspects of pollution in Lake Naini Tal, U.P., India, which is characterized by heavy input of domestic sewage and other organic pollutants. The most probable number (MPN) for coliform Bacteria varied from 0.59 × 105 to 3.61 × 105 per 100 ml, being highest in the monsoon season and lowest in spring. The water was alkaline in reaction throughout the period of study. The concentrations of dissolved oxygen showed high values near the surface and low ones in the bottom waters. BOD values always exceeded 6.0 mg/1. The concentrations of NO3−N and P04−P varied from 0.100 to 0.750 mg/1 and 0.018 to 0.153 mg/1, respectively. These concentrations are sufficient to cause blooming of certain phytoplankters on occasion. The values of NH3–N fluctuated from 0.033 to 0.422 mg/1, being highest in winter and lowest in the monsoon months. Among the metallic ions, the values of Pb and Mn were higher than permissible limits.The bottom sediments of the Lake were also found to produce toxic gases such as CH4, H2S, and NH3. Most of the carp fishes, such as Cyprinus carpio specularis, Tor tor, and Schizothorax spp., were found to be infected with Saprolegnia or other Fungi, or with trematodes. Certain phytoplankters (such as species of Microcystis, Anabaena, etc.), zooplankters (such as species of Bursaria, Spirostomum, Phillodina, etc.), and macrobenthos (including Tubifex tubifex, Limnodrilus sp., Chironomus plumosas, etc.), were found to be abundant. Macrobenthic species were absent from the profundal zone of the Lake, which showed all the important characteristics of a polluted water-body.