DefinePK

Abstract

This study evaluates pollution sources and water quality status in the Turag River, Bangladesh, using Geographic Information System (GIS) techniques and Water Quality Index (WQI) assessment. The Turag River, classified as environmentally critical since 2009, faces severe degradation due to untreated industrial effluents from pharmaceutical facilities, textile mills, and manufacturing units located along its banks. Water samples were collected from nine strategic locations and analyzed for eight physicochemical parameters (pH, dissolved oxygen, biochemical oxygen demand, total suspended solids, turbidity, phosphate, nitrate, and temperature) using standard protocols. GIS-based spatial mapping revealed significant spatial heterogeneity in pollution levels, with BOD values (53-90 ppm, mean 73 ppm) and turbidity levels (40-80 NTU, mean 58.77 NTU) exceeding Department of Environment standards at all sampling sites. The calculated WQI values ranged from 35.14 to 38.83 (average 36.68), placing the river water quality consistently in the "Bad" category across all sampling locations. The northern section exhibited critical conditions for dissolved oxygen (3.4-3.5 ppm) and turbidity (75-80 NTU), while the southern segment showed elevated levels of BOD, phosphate, and nitrate. The consistently poor water quality classification indicates severe degradation, limiting usability to agricultural irrigation purposes only. These findings provide a foundation for developing targeted pollution control strategies and highlight the urgent need for comprehensive watershed management to restore this vital water resource.