Groundwater geochemistry using modified integrated water quality index (IWQI) and health indices with special emphasis on nitrates and heavy metals in southern parts of Tirupati, South India.

Groundwater is particularly vulnerable to pollution in places with a high population density and extensive human usage of the land, especially in southern parts of Tirupati, India. To assess this, 60 bore-well samples were obtained and assessed for physical specifications, ion chemistry, and heavy metals during the pre- and post-monsoon seasons 2022. The current investigation employed a modified integrated water quality index (IWQI), conventional graphical and human health risk assessment (HHRA) of nitrates and heavy metals to know the groundwater chemistry and its detrimental health effects on humans. The major ions were analyzed using American public health association (APHA) standards, whereas heavy metals were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). Additionally, pH Redox Equilibrium and C (PHREEQC), a geochemical model written in C programming language was employed to determine the saturation indices of mineral facies and ArcGIS 10.3.1 was used for spatial distribution patterns of IWQI. Then, the HHRA of nitrates and heavy metals was performed using United States environmental protection agency (US EPA) guidelines. The noteworthy outcomes include elevated levels of Ca2+, Mg2+, Cl-, NO3-, Cu, Fe, Mn, and Pb, demonstrating rock-water interaction, silicate weathering, Ca-Mg-HCO3 followed by mixed water facies, dissolution/precipitation, reverse exchange, and anthropogenic contamination are the major controlling processes in groundwater of southern Tirupati, India. The modified IWQI reveals that most groundwater samples (38%) fall under the bad quality class, with (47%) in the poor quality class and only (15%) classified as medium quality class in pre- and post-monsoon seasons. Elevated IWQI were observed in all directions except in the east, which is suitable for drinking. Moreover, the major hazard quotient (HQ) and hazard index (HI) for nitrates (NO3-) and heavy metals like copper (Cu), iron (Fe), manganese (Mn), lead (Pb) and zinc (Zn) are above the critical value of 1, revealing potential risk to humans, especially infants, followed by children and adults, entailing the instantaneous implementation of proper remedial measures and stringent policies to reduce the risk associated with groundwater pollution in the southern parts of Tirupati.

Data sets on spatial analysis of hydro geochemistry of Gudur area, SPSR Nellore district by using inverse distance weighted method in Arc GIS 10.1.

The data represent on specific water quality monitoring parameters for 40 sampling points at Gudur area and Hydro geochemistry showed as spatial variation diagrams such as pH, TH, EC, TDS, SO4, HCO3, Ca, Mg, Na and F of Gudur area. The spatial maps show that high concentrations of physicochemical parameters in the North-East (NE) and South-East (SE) directions have been observed. The proper planning and various management activities were carried out with the help of these maps. The Gibbs diagram indicates the rock water interaction and bivariate plots data indicates the silicate weathering processes.

Data sets on delineation of groundwater potential zones identified by geospatial tool in Gudur area, Nellore district, Andhra Pradesh, India.

The data deals with the preparation of the groundwater potential zone map of gudur area, with the help of data like geology and geomorphology, structure/lineament, slope and drainage and the thematic layer were prepared through the Survey of India toposheet Nos. N/12,N/15,N/16 and IRS-P6 LISS-III(RESOURCESAT-2) satellite data. The groundwater potential zones were obtained and classified into four categories, viz., very poor, poor, good, and very good zones. The data explains lateritic plain moderate basement with poor potential zones whereas secondarily occupies alluvial plain contains the good prospecting zone.