Physicochemical Assessment of Surface and Ground water Quality of the Greater Chittagong Region of Bangladesh

Abstract

The study was carried out to assess surface and groundwater quality of the greater Chittagong (Chittagong and Cox’s Bazar districts) and Chittagong Hill Tracts (Rangamati, Khagrachhari and Bandarban districts) of Bangladesh. To study the various physicochemical and microbiological parameters, surface water samples from the Karnafuli, Halda, Sangu, Matamuhuri, Bakkhali, Naf, Kasalong, Chingri and Mayani Rivers, Kaptai Lake and groundwater samples from almost every Upazilas, smaller administrative unit of Bangladesh, were collected and analyzed. The statistical methods of sampling were used for collecting samples. Samples were preserved using suitable preservation methods. Water samples from the freshwater resources were collected from different points and tide conditions and at different seasons for continuous monitoring during the hydrological years 2008-2009. The collected samples were analyzed for the following parameters: pH, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), total solids (TS), dissolved oxygen (DO), transparency, acidity, dissolved carbon dioxide, total alkalinity, total hardness, chloride, ammonia-N, hydrogen sulfide, sulphate-S, o-phosphate-P, biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate-N, nitrite-N, total nitrite and nitrate-N, arsenic, iron, manganese, copper, nickel, chromium, cadmium, lead, calcium, magnesium, sodium and potassium using the procedure outlined in the standard methods. Average values of maximum physicochemical and microbiological parameters studied for the Karnafuli River were found higher than the World Health Organization (WHO) guideline. The maximum water quality parameters of Kaptai Lake and other Rivers of Chittagong region were existed within the permissible limits of WHO guideline. The data showed the water quality slightly differs in pre- monsoon and post-monsoon than monsoon season. The concentration of different constituents of most of the groundwater samples were within the permissible limits of BSTI drinking water quality guideline except As, Fe, and Mn. Results of water quality assessment identified the problem areas in respect of arsenic. The results also provided data to understand and quantify the threat of the impact of climate change on freshwater resources of this region. The results also provided data for water quality of surface and groundwater resources of Chittagong region to match national and international standards for drinking, agricultural, industrial and livestock requirements.