ECOLOGICAL RISK ASSESSMENT OF A TROPICAL LAKE SYSTEM

Abstract

Risk analysis of urban aquatic systems due to heavy metals turns significant due to their peculiar properties viz. persis tence, non-degradab ility, toxicity, and accumulation. Akkulam Veli (AV), an urba n tropical lake in south India is subjected to various environmental stresses due to multiple waste discharge, sand mining, developmental activities, tour ism related activitie s etc. Hence, a comprehensive approach is adopted for risk assessment using modified degree of contamination factor, toxicity units based on numerical sediment quality guidelines (SQGs), and potentialecological risk indices. The study revealed the presence of toxic metals such as Cr, C d, Pb and As and the lake is rated under ‘low ecological risk’ category.