Pollution Research Paper

SEDIMENT TEXTURE AND ORGANIC CARBON DISTRIBUTION PATTERNS IN THENGAPATTINAM ESTUARY, TAMIL NADU, SOUTH-WEST COAST OF INDIA

D. HELEN AND A. RAMALINGOM PILLAI

Abstract

Detailed texture and organic carbon percentage of the sediments of Thengapattinam estuary covering the entire biotope from the marine to the riverine zone are presented. This estuarine system in Tamil Nadu is found to be a zone of pollution caused by sewage entering the estuary through AVM canal, inflow of water from paddy fields and coconut plantations and also the retting of coconut husk .Seasonal variations of organic carbon content in the sediments were studied in relation to textural pattern. The present study reveals that textural pattern determines the selective enrichment of organic carbon. The sediments are mainly sandy loam, loamy sand, sandy clay loam and sand. In monsoon season the sediment was mainly sandy clay loam with higher levels of clay and in the post monsoon and pre monsoon seasons the sediment was found to be sandy loam and loamy sand except in the mouth of the estuary. The organic carbon content varied from 0 % to 1.326 %. Low level of sediment organic carbon was noticed in monsoon season. Correlation between texture and organic carbon reveals that fine grained sediments like sandy loam, loamy sand and sandy clay loam have higher OC content than sand. Hence sediments in the estuarine region have relatively higher OC content than the mouth of the estuary and the riverine system.