Identifying the Influence of Fluoride Mobilization Mechanism on Groundwater Quality Dynamics of Sanghar District, Lower Indus Basin

Abstract

Groundwater contamination is one of the major concerns of  deltaic plain areas of lower Indus basin. Forty ground water samples from hand pumps were geochemically evaluated and investigated to ascertain the quality of water in three union councils of District Sanghar, Sindh. Study was conducted to identify the mobilization mechanism of fluoride and its impact on the concentration trends of groundwater quality. Water quality is assessed for measuring the levels of pH, TDS, Ca, Mg, Na, HCO₃, SO₄, SAR and Nitrate (NO₃-N). Results revealed that Fluoride concentration was 3.1-9.2 mg/L and Nitrate 0.2-0.8 mg/L as per WHO permissible limits. The value  of pH was found 7.0-8.3, which shows a dominancy of alkaline concentrations in groundwater. Chemical analysis revealed Na-Cl is  accompanied by the ion pair of Ca-HCO₃. Hydrogeochemical classification specifies the mixed-type concentration inclining Na-K-type ionic concentrations. Analytical studies exhibited that the areas rich in Ca²⁺  display a comparatively low concentrations of dissolved fluoride. It is found that alkaline environment is favorable for  F^- dissolution in gorund water of the study area.