Rethinasamy Geetha, Kittappa Gunasundari, Rajasekaran Sabapathi and Rathinasabapathi Hemalatha
Abstract
Groundwater is the primary source of drinking water in Ariyalur district, Tamil Nadu, necessitating regular quality assessment. This study examined seasonal variations in physico-chemical parameters of groundwater from Udayarpalayam, Sendurai, and Ariyalur taluks during pre- and post-monsoon periods. Parameters including pH, EC, TDS, total hardness, major cations (Ca²+, Mg²+, Na+, K+), anions (chloride, sulphate, nitrate, phosphate, fluoride), ammoniacal nitrogen, and barium were analyzed using standard APHA methods. Higher values in the pre-monsoon samples reflected evaporation and salt concentration, while post-monsoon dilution reduced most constituents. In several locations, TDS, total hardness, chloride, and nitrate exceeded BIS (2012) limits, indicating contamination from agricultural runoff, sewage, and geogenic sources. Ariyalur taluk showed pronounced seasonal variation, whereas Udayarpalayam remained relatively stable. The study underscores significant seasonal fluctuations and the importance of continuous monitoring to safeguard groundwater resources.