Poly Paul, Jwngma Narzary and Jahnovi Brahma
Abstract
This paper represents the assessment of water quality of a small Gaurang River flowing nearby Kokrajhar Town of Assam. The assessment was conducted using physico-chemical parameters like Dissolved oxygen (DO), free carbon dioxide (CO2) and Total alkalinity along with study on the diversity of phytoplankton as indicator for pollution. In the present study the Dissolved Oxygen level of upstream, i.e. in upper zone of the study area was found with non pollution tolerant species. Whereas in downstream, i.e. in lower zone of study area more pollutant tolerant species were recorded with low Dissolved Oxygen concentration. In upstream family chlorophyceae was found as most dominant family whereas in downstream Bacillariophyceae was found as most dominant which indicates more pollutant species in downstream. The Gaurang River becomes polluted in lower zone due the sewage drainage system and urbanization.