Water has been used since antiquity as a symbol to express devotion and purity. With twothirds
of the earth?s surface covered by water and the human body consisting of 75% of
it, it is evidently clear that water is one of the prime elements responsible for life on earth.
A lake is a low lying part of the earth?s surface, in which rainwater, surface water runoff,
outflow from a river, and water from other sources accumulate. There is a great variety of
lakes on the earth: there are freshwater lakes and saltwater lakes, ranging in size from small
fish ponds to huge water bodies. India has a large number of lakes spread all over the country,
from Kashmir to Kerala and from Rajasthan to Assam. Among the better-known freshwater
lakes in India are the Dal lake in Srinagar and the Nainital lake. Whether natural or manmade,
all lakes are major sources of water. Lakes are degraded, depleted and contaminated mainly
by human activities. The main causes are inflow of domestic sewage, agricultural runoff,
discharge of industrial effluents, overfishing, introduction of exotic species and habitat
degradation from population growth and expansion of cities. Hussain Sagar lake in Hyderabad
is one of the largest manmade lakes in Asia.
Escherichia coli (the predominant member of fecal coliform group), is a member of enteric
bacteria whose presence in natural waters is used as an indicator of faecal contamination,
and therefore the possible presence for pathogenic microorganisms (Rhodes and Kator, 1998),
but their absence does not necessarily guarantee quality of water (Dutka, 1973). Sewage
effluent contains a wide range of pathogenic microorganisms which may pose health hazard
to human population when they are discharged into the water bodies (Borrego and Figueras,
1997) and the health hazard could be severe in a heavily populated country such as India.
Though some published data are available on the water quality of the study area (Hussain
Sagar lake, Durgam Cheruvu lake, Saroornagar lake, Safilguda lake), there are virtually no
reports available on the pathogenic bacteria from the present study area. Hence the present
study was carried out with an objective to identify some common pathogenic microorganisms.
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