The purpose of this study is to evaluate the quality of groundwater for drinking and irrigation in the Avudaiyarkoil block of the Pudukottai district, which is a drought-prone region. Samples were collected from 20 wells on January 2021 and analysed for the water quality parameters, such as pH, EC, TDS, Ca2+, Mg2+, Na+, K+, Cl-, HCO3, SO4, NO3 and F-. The analysis revealed that SO4 is the dominant ion followed by Cl-, HCO3-, Na+, Ca2+, Mg2+, K+, NO3- and F- with respect to the mean value 292>234>208.4>125>100>24.75>18>16.15>0.2. The analytical results were compared with WHO and BIS guideline values to know the groundwater potability and TH, TA, SAR, Na%, RSC, PI, MgC and KI were calculated using the analytical results to identify the suitability of groundwater for irrigation purposes.

The study of sedimentary characteristics and paleontology is very useful in assessing the past environment of a study area. The Karankadu estuary study area is considered to be one of the most ecologically diverse in the Ramanathapuram district of southern India. The sedimentological and recent foraminiferal assemblages were studied using a drill core from the estuary. Foraminifera analyses, grain size analyses, heavy mineral analyses and XRD maps were prepared for the present study. A total of 30 species were identified from the following suborders: Rotalina, Lagenina, Mollusca, Miliolina, and Textularina. Grain size analysis identified the substrate as mostly silty clay. Heavy mineral analysis identified 90% of light minerals and 10% of heavy minerals. In XRD analysis, quartz and feldspar appeared as major minerals and garnet, zircon, hypersthene, magnetite and ilmenite as minor minerals. The present study shows that the environment is more diverse due to its quiet character and less responsive to hazardous events such as floods and waves.

The historical shoreline changes from 1980 to 2020 along the Manamelkudi coast is studied using toposheet, satellite time-series Landsat data, and observed data. An attempt is made to recognise possible factors which are responsible for shoreline changes and spit growth at south Manamelkudi coast (Palk Strait), Eastern part of Pudukkottai district, Tamilnadu. During 1980–2020, the regions showed distinct spatio-temporal variability, which is discussed in relation to spit evolution and shoreline changes. The study also generated a long-term (1980-2020) shoreline change statistics (EPR, LRR, SCE and NSM, WLR) using the Digital Shoreline Analysis System (DSAS) at every 150 m interval for the Manamelkudi coast covering 42 km, identified the erosion and accretion and divide the shoreline into different classes of erosion and accretion. Identified lengths of shoreline with high erosion, low erosion, stable, low accretion and high accretion are, respectively, based on LRR. The results indicate that spit evolution is predominant along the Manamelkudi coast, with the highest percentage of erosion and accretion.