Evaluation of hydrochemistry of the Dokri groundwater, including historical site Mohenjo-Daro, Sindh, Pakistan

ABSTRACT

The 40 georeferenced groundwater samples were randomly collected from taluka Dokri, district Larkana, Sindh, Pakistan to access the water quality of groundwater owing to the increasing water scarcity. The sampling including historical site Mohenjo-daro meaning ‘Mound of the Dead Men and mapped spatially using ArcGIS 10.5 software. It was built about 2500 BCE and was largest settlements of ancient Indus Valley Civilisation and an earliest major city of the world. The samples were examined for physical and chemical parameters using standard methods and analysed for 26 physicochemical parameters including cations, anions, trace and toxic elements for drinking and irrigation purposes. The 27.5% samples were not suitable for drinking purposes on the basis of TDS. Principal component analysis, cluster analysis, and correlation analysis were examined to interpret the data. Hydrochemical faces, scatter analysis and Chadha diagram were analysed to know the groundwater chemistry and to interprete the data. The Chadha diagram showed that (70%) samples fall within, Cl⁻+SO₄^2–Ca²⁺+Mg²⁺, SO₄^2–Ca²⁺+Mg²⁺and showed dissolution of gypsum containing minerals, Gibbs diagram showed 62.5 to 65.0% samples were in Rock dominance. The GIS mapping results of water quality parameters revealed that in most of the groundwater of taluka Dokri was good for drinking except Mohenjo- daro site. The water quality index (WQI) was calculated and 65.0% samples were in ‘Good and Excellent’ category for drinking purposes and 92.5% samples were found in ‘Good to Excellent’ category for irrigation. The samples were calculated for SAR, RSC, PI, KI, Na% to check the water quality for irrigation and 75–100% were observed suitable for irritation. The work may provide guideline for examining the water quality for drinking and irrigation in their respective areas.

KEYWORDS:

• Water quality for drinking and irrigation
• Mohenjodaro
• WQI
• weathering and ion exchange process
• groundwater

Disclosure statement

The authors declare that they have no conflict of interest.