Hard rock aquifers of Indian peninsula are loaded with excess nitrate due to heavy use of fertilizers during irrigation and excess fluoride due to the geogenic contamination. This study is focused on the groundwater quality in Subledu Basin in view of the large-scale use of groundwater for both irrigation and drinking purposes as no such study was carried out earlier in the basin. The study area is located at Khammam district, Telangana state, India, which is a hard rock terrain mostly covered with granites and gneisses. Twenty-two groundwater samples were collected covering the entire basin in the month of May 2019 from running hand pumps for analyzing the major anions and cations in the groundwater. The samples were analyzed by using standard gravimetric method for evaluation of total dissolved solids; titrimetric methods to analyze carbonates, bicarbonates and chloride; UV spectrometric method for estimation of nitrate; and ion-selective electrode method for fluoride and spectrophotometer for sulfate and phosphate. These chemical constituents are used to calculate parameters, namely total hardness, sodium adsorption ratio, residual sodium carbonate, sodium percentage, Kelley’s ratio and magnesium hazard. The spatial distribution maps of important chemical constituents are prepared by using the contour maps created by utilizing the inverse distance weighted interpolation tool in the Geographical Information System. The excess fluoride values of 2.84 mg/l, 2.76 mg/l and 1.87 mg/l are observed in the villages of Pocharam, Kistapuram and Turakagudem, respectively, as against the maximum permissible concentration of 1.5 mg/l prescribed by World Health Organization. Excess use of fertilizers for agriculture is causing the nitrate pollution of groundwater in more than 50% of the samples with concentrations ranging from a minimum of 2 mg/l to a maximum of 460 mg/l in the villages of Medidapalle and Bachodu. It is identified that the total hardness is ranging between 200 and 820 mg/l which is very high when compared with the Bureau of Indian Standards. Based on sodium adsorption ratio, residual sodium carbonate, Kelley’s ratio, and sodium percentage analyses, two samples were not suitable for irrigation. Similarly, 13 samples are not suitable for drinking water purposes based on the excess presence of fluoride and nitrate. Groundwater quality maps of Subledu Basin depicting the areas suitable or not for the irrigation as well as for drinking purposes were prepared. From these maps, it is found that groundwater from large parts of the basin is not suitable for drinking purposes while for irrigation purposes it is suitable.

印度半岛的硬岩含水层由于灌溉期间大量使用肥料而含有过量的硝酸盐，而由于地质污染而含有过量的氟化物。鉴于大规模用于灌溉和饮用水目的的地下水，本研究着重于Subledu盆地的地下水质量，因为该流域的早期没有进行过此类研究。研究区域位于印度Telangana州的Khammam区，这是一块硬岩石地带，大部分覆盖有花岗岩和片麻岩。2019年5月，从运行中的手动泵收集了整个盆地的22个地下水样品，以分析地下水中的主要阴离子和阳离子。使用标准重量分析法对样品进行分析，以评估总溶解固体；滴定法分析碳酸盐，碳酸氢盐和氯化物；紫外光谱法估算硝酸盐；氟化物的离子选择电极法和硫酸盐和磷酸盐的分光光度计。这些化学成分用于计算参数，即总硬度，钠吸附率，残留碳酸钠，钠百分比，凯利比和镁危害。重要化学成分的空间分布图是通过使用等高线图绘制的，该等高线图是利用地理信息系统中的距离反距离加权插值工具创建的。在Pocharam，Kistapuram和Turakagudem村，分别观察到2.84 mg / l，2.76 mg / l和1.87 mg / l的过量氟化物值，而世界卫生组织规定的最大允许浓度为1.5 mg / l。在Medidapalle和Bachodu村中，过量使用化肥在超过50％的样品中引起地下水硝酸盐污染，其浓度范围从最小2 mg / l到最大460 mg / l。可以确定，总硬度在200至820 mg / l之间，与印度标准局相比非常高。根据钠吸附率，残留碳酸钠，凯利比和钠百分比分析，两个样品不适合灌溉。同样，由于氟化物和硝酸盐的过量存在，有13个样品不适合用于饮用水。制作了Subledu盆地的地下水水质图，描绘了适合灌溉或不适合灌溉的区域。从这些地图中