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The water body of Hooghly estuary is contaminated by unrestrained discharge of
treated and untreated domestic and industrial waste into the river. Physicochemical nature
and sediment characteristics though reveal a periodic picture of the concerned water body,
but sustainable records are not available. Periodic and heavy rainfall many times dilutes
the situation. In this regard, macrobenthic forms being sedentary fauna of the very habitat
reflects the deterioration of water and soil of the
ecosystem. Limnodrilus hoffmesteri, a
tubificid macrobenthic form is famous as a pollution indicator of estuarine ecosystem (Bu-Olyan
and Thomas, 2005). Studies on the Hooghly estuary were made by several workers, but
the portion from Konnagar to Ariadaha of the estuary, which is linked with municipal and
industrial discharges, has not yet been studied. The present work aims to record the incidence of L. hoffmesteri in accordance with physicochemical nature of water and soil of the
Hooghly estuary.
Water samples were collected from the two stations. These samples were carried to
the laboratory for chemical analysis following the standard methods (APHA, 1998). The
collected wet soil samples were dried, grained and analyzed following the standard methods
(Jackson, 1973). The organisms were sorted manually and preserved in 4% formaldehyde solution
for further examination.
Among the water parameters (Table 1), the average water temperature of station-A was
30.2 °C and station-B was 29.5 °C. The average water pH of the studied station-A
was 8.5 and of station-B was 7.5. The amount of dissolved oxygen of the station-A was
2.5 mg L–1, while it was 7.2 mg L–1 in station-B. The amount of free CO2 at station-A was 2.3 mg
L–1, while it was too low at station-B. Water alkalinity was higher (101.0 mg
L–1) at station A, and it was lower (47.9 mg
L–1) at station-B. Hardness of station-A was higher
(120.2 mg L–1), while it was minimum (54.1 mg
L–1) |
