Spatio-temporal Variability of Physico-chemical and Biological Water Quality Parameters of River Ganges in Six Cities Situated on Indo-Gangetic Plain Transect

Abstract

Rivers in any country are important lifeline for the population living around it whose water is used for drinking, agriculture, industrial and commercial purposes. The increasing anthropogenic activities like industrialisation, urbanisation and change in land use pattern, increased use of chemical fertilizer and pesticides in farming have lead to the discharge of the different types of contaminants in the river water. In the present article, the data has been acquired from Central Pollution Control Board, India which continuously monitors different kinds of water quality parameters every year at regular interval. The data analysis of the different biogeochemical water quality parameters of river Ganges has been carried out. In the present study, a total of six cities have been chosen to analyse the water quality of the river Ganges. The chosen six cities are Haridwar, Kanpur, Allahabad, Varanasi, Patna and Kolkata which are situated along the stretch of the river Ganges. The Haridwar is located at a place where the river Ganges enters the Northern Indian Plain from mountainous (Himalayan range) region while Kanpur, Allahabad, Varanasi and Patna are located on Plain and Kolkata is situated on the Deltaic region of river Hooghly which is one of the distributaries of river Ganges. For the analysis purpose, a total of eight water quality parameters which decide the contamination levels of the water bodies have been selected. These parameters are temperature, dissolved oxygen, pH, conductivity, Biological Oxygen Demand, Nitrate + Nitrite, Faecal Coliform and Total Coliform load. The study has been carried out with respect to the data from 2007 to 2016. In this ten years period, the data of four years i.e., 2007, 2010, 2013 and 2016 have been selected having gap of two years. In the spatial analysis of the result, it has been found that the river Ganges in Haridwar is least contaminated and the Kolkata is highly polluted in terms of the eight water quality parameters studied. In the correlation matrix analysis, the population of the city is negatively correlated with the altitude, temperature, dissolved oxygen while positively correlated with conductivity, BOD, Nitrate + Nitrite, Faecal Coliform and Total Coliform load. With regard to the Coliform contamination, except at Haridwar, rest of the river flow through the five cities indicated the Coliform contamination was many time above the standard limits prescribed by the CPCB.