Assessment of heavy metals in groundwater around Koppal Taluk, Koppal Dist. Karnataka by using multivariate analysis, metal pollution indices, and GIS technique

Groundwater is a crucial environmental resource with significant economic and public health implications. This study investigates aquifer water quality in Koppal taluk, Karnataka, India, where agricultural practices, unregulated groundwater extraction, and industrial activities, particularly steel manufacturing, pose potential contamination risks. Given the local population's reliance on groundwater for daily needs, the presence of even trace amounts of toxic elements raises serious health concerns. Therefore, this research analyzes the concentrations of trace metals in the aquifers. Twenty-five groundwater samples were collected seasonally from December 2022 to November 2023 and analyzed using Inductively Coupled Plasma - Optical Emission Spectrometry. The Metal Index, Geo-accumulation Index, and Heavy Metal Pollution Index were employed to interpret the data. Multivariate statistical and integrated techniques were applied to examine interrelationships among variables. Factor analysis revealed that Zn, Fe, and Cu exhibited significant variability, accounting for 62.10%, 65.10%, and 77.17% of the total variance during the pre-monsoon, monsoon, and post-monsoon seasons. Cluster analysis indicated a common source for most of the detected trace metals. The spatial distribution of heavy metals was visualized using the Inverse Distance Weighting tool in ArcGIS 10.8. The observed heavy metal concentrations were within the permissible limit compared to the Bureau of Indian Standards IS:10500 and World Health Organization guidelines. HPI values below 100, MI values between 0 and 3, and I_geo values between 0 and 1 suggest that the groundwater is potable. This study offers valuable information for policymakers to develop effective regional pollution mitigation strategies.