DOI: 10.36347/sjet.2019.v07i08.007

Pages: 245-251

Over the last 20-30 years, most of the rivers around Dhaka city including Sitalakhya have become increasingly threatened due to indiscriminate anthropogenic pollution. The erratic and uneven rainfall over time and space, a prolonged dry period due to climate change phenomenon has been worsening the situation. Abrupt changes are observed in the raw water quality of this river on a seasonal basis. Thus the seasonal water quality information is becoming essential as to take important decisions on drinking water pursuit and beyond. Assessment of the quality status & the seasonal trend of the Sitalakhya river water quality in Bangladesh is made in terms of water quality index (WQI), a numerical value to express its quality, based on physical, chemical and biological measurements using the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI). Water samples were analyzed for quality parameters as recommended in the Bangladesh Standard (ECR 1997) on the ‘best practice based classification for drinking water supply after conventional treatment’ and the compliance level is compared with the limits as stated in the guideline. Out of the four seasons in a year, in the dry season (winter, December to February) and the hot summer season (pre-monsoon, March to May) of this study period, WQI values varies from 40 to 45(out of 100), reflecting poor water quality as per ratings attributed to WQI. In the monsoon season (June to September) the WQI varies in between 49 to 64(Marginal to fair) and autumn (October to November) it varies in between 47 to 63 (Marginal to fair) indicating comparatively fair water quality. In comparison, in the monsoon season, the water is the best available water in the river. An alarming message is that the water quality has been deteriorating very fast.