Assessment of Groundwater Quality in a Tidal River Basin of the Ganges Delta in Bangladesh

Sadhon Chandra Swarnokar,Nazia Hassan,Mosummath Hosna Ara,Masudur Rahman,Md Muhyminul Islam

doi:10.4236/gep.2019.75013

Abstract

At Shailmari River basin, located in the central Ganges Delta and the southwestern coastal Bangladesh, groundwater is the only potable source for water supply due to incompatible surface water sources. However, salinity degradation along with arsenic and iron contamination poses a serious health threat to the basin community. Considering this, an investigation was carried out along both banks of the river to assess groundwater vulnerability and its quality for drinking by conducting multi-seasonal water sampling campaigns from 20 domestic wells and analyses (both in-situ and laboratory) for several physico-chemical (pH, EC, TDS and major ions) and biological (coliforms) parameters. The results show slightly alkaline groundwater in the study area with largely variable chemical composition, i.e. EC varies from around 1900 to 2700 μS/cm. The abundance of major ions indicates as Na+ > Ca2+ > Mg2+ > K+ for cations and > Cl- > > > for anions. As per the Canadian water quality index (CCMEWQI), almost all groundwater samples concentrate in the marginal category meaning that groundwater is frequently threatened. Besides, it is not fully safe for drinking as revealed from comparison of geochemical data with national and WHO water quality standards.

Highlights

More than 50 million inhabitants of coastal area depend on ground water for encountering their drinking, domestic and irrigation uses, directly related to poor drinking water quality attributed by water borne pathogens, fecal coli forms and various toxic pollutants (UNESCO, 2007; Kumar et al, 2009; Chitradevi & Sridhar, 2011; Pethick & Orford, 2013)
Almost 80% people rest on ground water fed irrigation and approximately 97% people depend on drinking water supplies that come from groundwater via hand-operated tubewells (Shamsudduha et al, 2009)
The result of the study from hydro-chemical characterization elicits that the ground water in the adjacent river basins is hard, fresh to brackish and alkaline to saline in respective different seasons

Summary

Introduction

Being an agro based country, Bangladesh possesses 5,049,785 ha agro-arable land which depends on adequate water supply from both groundwater (80.60%) and surface water (19.40%) of usable quality (Shahid et al, 2006; Hasan et al, 2007; Vyas and Jethoo, 2015; Islam et al, 2016). Almost 80% people rest on ground water fed irrigation and approximately 97% people depend on drinking water supplies that come from groundwater via hand-operated tubewells (Shamsudduha et al, 2009). A detailed investigation of shallow and deep tubewells along the bank of Shailmari River connected with Rupsha-Kazibacha River system could be a very realistic study to assess the quality of groundwater through hydro-chemical investigation and water quality indexing

Methods

Results

Conclusion