Interpretation of groundwater quality using principal component analysis from Anantapur district, Andhra Pradesh, India

摘要

Groundwater samples from the Anantapur district, Andhra Pradesh, India, are analyzed for chemical constituents to identify the hydrogeochemical processes that control the groundwater quality. The groundwater is brackish and very hard, with an excess alkalinity, and is not fit for drinking and irrigation. Principal component analysis is made on the chemical variables, and the first two principal components are chosen, which account for 77.34% of the total variance in the data set. The first principal component is characterized by total dissolved solids, Na+, Cl–, , , pH and F– parameters, and the second principal component is represented by Ca2+, , Mg2+ and ions. These components are interpreted as controlled by the higher rate of evapotranspiration, topographic lows, poor drainage conditions, longer residence of water in the aquifer, ion exchange, irrigation return flow, heavy use of fertilizers, and sewage wastes, which are further supported by the scatter diagrams, ionic signatures, and mechanisms controlling the water chemistry diagrams. The principal component scores clearly explained the variations in the local and regional hydrogeochemical processes, broadly distinguished the geogenic sources from the anthropogenic ones, and easily helped to select the index wells for the long-term monitoring, which would reduce the cost of monitoring programs. The principal component analysis in the present study area is assisted to facilitate the determination of assemblages of groundwater quality results, which explain the genetic processes and points of origin of pollutants of residential and agricultural zones for mitigating the adverse effects caused by the inferior quality of water on the human health as well as on plant growth for sustainable development. Hence, the application of the principal component analysis can be used as a complementary tool in the hydrogeochemical analysis of any region and helps to plan appropriate management measures in time to control and improve the groundwater quality.