Identification of the sources for groundwater salinization in the coastal aquifers of Southern Tamil Nadu, India

The increasing demand of water resources leads to decline the groundwater table, and it leads to saline intrusion in the aquifers of coastal areas. Hence, the need for monitoring and identification of saline intrusion in groundwater is to be recognized for sustainable utilization of that precious resource. A detailed hydro-chemical study was undertaken to identify the sources of groundwater salinization in the coastal aquifers of Southern Tamil Nadu, India. The present investigation of hydro-chemical study infers that the groundwater samples in the study area are generally characterized by fresh to brackish, moderately hard to very hard and alkaline in nature. The Piper plot shows that most of the groundwater samples in the north-eastern region were Na⁺–Cl⁻ type, while in the south-west and the western region no particular cation shows clear dominance. Though, the dominance of chloride was observed throughout the study area. The investigation of hydro-chemical evolution reveals that sea water intrusion may be possible for the source of groundwater salinization in the aquifers of the north-eastern region, whereas reverse ion exchange is the major process for controlling the hydro-chemical evolution of groundwater in the south-west and the western region. The results of principal component analysis and hierarchical cluster analysis are also concomitant with the hydro-chemical interpretations.