Drinking Water Insecurity in the Coastal Parts of Mirsharai, Sonagazi and Companiganj Areas of Bangladesh: A Multi-Parameter Analysis of Water Quality

Abstract

The people of the coastal parts of Bangladesh are insecure for safe drinking water. Therefore, the

present research is an attempt to delineate the water quality in the coastal parts of Mirsharai, Sonagazi and

Companiganj areas. Various parameters of water quality such as free hydrogen (pH ), electrical conductivity (EC),

total dissolved solids (TDS), oxidation reduction potential (ORP), salinity, turbidity, dissolved oxygen (DO),

biological oxygen demand (BOD), chemical oxygen demand (COD), acidity, alkalinity, total hardness and nitrate,

phosphate, sulphate, chloride, iron, manganese, cobalt, nickel, arsenic and chromium were determined through

field work and, from published and unpublished literature. The results indicate that the arsenic concentration and

electrical conductivity in shallow aquifers exceed WHO and Bangladesh standard limit. Additionally, chloride,

total hardness, alkalinity, and lead exceed the WHO Bangladesh standards in both shallow and deep aquifers. In

many cases, the turbidity of surface water both inside and outside the coastal embankments exceeds WHO and

Bangladesh standards. The lead, chloride and manganese content and, DO and BOD in the Feni River also exceeds

the WHO Bangladesh and BSTI limits. The analysis reveals that the deep aquifer is free from arsenic, while the

shallow aquifer is significantly contaminated. Although the deep aquifers need precaution for salinity, alkalinity,

total hardness, lead content etc. Correlation matrix analysis confirms that EC and TDS serve as reliable indicators

of salinity levels in both shallow and deep aquifers. Principal Component Analysis (PCA) further supports this,

showing that EC, TDS, and salinity are influenced by the intrusion of saline water in these aquifers. Additionally,

pollutants in both shallow and deep aquifers are positively associated with EC, TDS, and salinity.

Keywords: Drinking water insecurity, water quality analysis, coastal areas, Bangladesh.