Seasonal Water Quality Trends at Diamond Harbour West Bengal: A Pilot Study

Abstract

Diamond Harbour is located on the Hugli river , which is a tributary of Ganges , tidal bore occurs here wherein the ocean water rushes into the rivers mouth , raising the water level’s and making the harbour accessible. Twenty Six water quality  parameters were analysed over a period of one year (2024). The analysis was done on the basis of the four major seasons of the year Winter, Summer, Monsoon and Autumn. Major variations in water quality parameters were observed for Summer season. Temperature was highest in summer compared to other seasons, also Turbidity, Total Hardness, TDS, Sulphate, Sodium, Potassium, Magnesium, Chloride, Calcium and Conductivity were found to be very high in Summer season compared to other seasons. While Fecal coliforms. E- Coli were found in  less concentration in summer compared to other seasons. The following parameters did not show much change in all four seasons BOD, Nitrate, pH, COD, Fluoride, Nitrite-N, Phosphate and Total Alkalinity. Diamond Harbour is basically a navigation point, high values of  hardness of water , TDS etc. much above permissible limits as prescribed by CPCB being observed here in Summer season could be due to  river’s concentration becoming high due to evaporation, resulting in the deterioration of its quality or mixing of sea water at Diamond Harbour. The correlation matrix for different season’s , showed a strong correlation between Winter and Autumn season, followed with Winter and Monsoon season concluding that similar treatment can be used on water in Winter and Autumn season and also to some extent in Monsoon season. Our study found that compared to other seasons, in summer season highest concentration of Magnesium, Sodium and sulphate ions was observed. A further analysis with decision tree model found that sulphate is the most important parameter, followed by COD for splitting the data set. Implementation of any water treatment technology is not useful unless the correct source is identified. Our study helped in identifying that high concentrations of Sulphate ions are responsible for hardness of water at Diamond Harbour in summer season.  Special monitoring of water hardness in summer season is required at Diamond Harbour, before the water can be used for any purpose. Future scope of work lies in enhancing the water treatment plants with ion – exchange technology which is very efficient in removing magnesium ions from water and reverse osmosis for removing sulphate and sodium ions from water , so that the water is safe to some extent for usage .