Comparative Study of Textural and Chemical Characteristics of Riverine and Estuarine Sediments of a bar Built Estuary in Tamil Nadu, India

Pazhayar is one of the main river systems in Kanyakumari District. It receives water from both Pechiparai and Perunchani reservoirs. The Pazhayar takes its origin at Surulacode. The total length of the river is about 37km and it passes through Boothapandi, Thazhakudi, Putheri, Nagercoil, Suchindrum and finally joins with Arabian Sea through a Manakudy estuary. The present investigation was done to evaluate the sediment characteristics of riverine and estuarine zones. For the study three stations were taken in the riverine zone (S1, S2 and S3) and three stations were selected on the estuarine zone (S4, S5 and S6).The sediment texture revealed the fact that grain size ranged from 0.063mm to 0.5mm. Sand was predominant in the riverine side. The mud (silt + clay) was abundant in the estuarine region than the riverine zone. The estuarine zone was highly silty. The sulphur content decreased from the riverine side to estuarine zone. The organic carbon also showed the same trend of decreasing from the riverine zone to estuarine region. However a negative trend was observed in calcium carbonate which increased from the riverine zone to estuarine region. Probably due to the abundance of molluscan shells in the estuarine zone. The various parameters of surface sediments in the six stations were subjected to two way ANOVA and it was found that they are significantly correlated. Keyword : Estuary, sediment, organic carbon, calcium carbonate, sulphur.