USING WATER QUALITY INDEX TO ASSESS GROUNDWATER SUITABILITY AT GAZIPUR DISTRICT, BANGLADESH

This study targeted to the suitability of groundwater for drinking purpose at Gazipur District undergoing rapid urbanization and increasing industrialization. The District has an area of 1741.53 km², located in between 23°53' and 24°21' north latitudes and in between 90°09' and 92°39' east longitudes. From six Upazilas in Gazipur District, a total of 130 groundwater samples were collected, which are, Gazipur Sadar Upazila, Sreepur Upazila, Kaliakoir Upazila, Kapasia Upazila, and Kaligonj Upazila. A recent field observation review of industrial sludge found that heavy metal concentration was above the acceptable limit for agricultural soil. Gazipur being adjacent to Dhaka and has a similarly complex situation about contamination and abstraction. In recent years, the District has seen rapid growth in industrial development and increased urbanization. Water Quality Index (WQI), calculated per Horton’s method, used to assess groundwater condition and its vulnerability by taking into account thirteen parameters, namely, pH, TDS, sodium, potassium, calcium, magnesium, iron, manganese, bicarbonate, chloride, sulfate, nitrate, and fluoride. The computed WQI shows that comparatively collected water sample falls in excellent categories with few high points, probably due to localized industry and urbanization growth. WQI for the district has been classified using GIS into four categories, namely, Low, medium, high and very high. About 12 samples indicated high to very high WQI values. Spatial distribution analysis and Tree-map indicate a comparatively high concentration of WQI near the industrial areas within the District. Highest concentrations are evident at Gazipur Sadar Upazila, where urbanization and industrialization within the Gazipur District are highest and increasing at a rapid rate.