EFFECT OF HYDROGEO-CHEMICAL PROCESSES AND SALTWATER INTRUSION ON GROUNDWATER QUALITY IN AQUIFERS OF HYDERABAD, SINDH.

Abstract

Hyderabad, a city in Pakistan's Sindh Province on the Indus River's banks, often has ground water conditions ranging from neutral to slightly alkaline. More than 69.8 percent of the samples had EC levels above the threshold considered safe for human consumption, and the same percentage of samples had TDS levels above the threshold recommended acceptable by the World Health Organization (WHO). In Sindh, hard groundwater predominates; 52% of the province's aquifers are classified as extremely hard water, making up the bulk of the province's water supply. Groundwater salinity was due to several minerals, including bicarbonate HCO3-, calcium Ca2+, magnesium Mg2+ and sodium Na+. There are several factors at play, including the high-water table, the incursion of seawater, the overuse of fertilizers, and the underlying geological structures, that have led to this reduction in water quality. The hydrogeochemical facies show that the concentrations of Na+ are larger than those of Ca2+ and Mg2+, and those of Cl- and SO4 2- - are more than those of HCO3-. As a result, it is hypothesized that the solutes in Sindh's groundwater originate from the weathering of carbonate deposits. Thirty percent (28.0%) of the groundwater is classified as "drinking quality" by the EC. Thirty percent of the groundwater is drinkable, as determined by the total dissolved solids level of the samples. It was discovered, however, that 57.3% of the groundwater is extremely hard. According to the SAR, 90% of GW may be irrigated on almost any type of soil with a negligible risk of Na exchange. Inadequate for direct use in agriculture, however, as testing showed that seawater intrusion made it unsuitable for irrigation.