Ecological Risk Assessment And Seasonal Variation Of Heavy Metals In Water, Sediment And Biota Collected From Shambhavi Estuary, Mulki, Karnataka

Abstract

This study investigated the levels of heavy metal contamination in the Shambhavi Estuary's water, sediment, and crab tissues. The results indicated that Fe had the highest concentration in both water and sediment, followed by Pb, Zn, Cr, and Cd. Moreover, the levels of all heavy metals in the water, sediment, and crab tissues exceeded the acceptable limits set by various international organizations, indicating a significant contamination issue. The study revealed that the levels of heavy metal contamination in the estuary's aquatic environment increased during the pre-monsoon, monsoon, and post-monsoon seasons, with waste discharge from industries, municipalities, and agriculture being identified as the primary source of pollution. The high levels of heavy metals detected in the water and sediment raised concerns about potential bioaccumulation in the estuary's most prevalent crab species, Astruca annulipes, which could pose a considerable threat to the ecosystem's integrity. The study's findings highlight the urgent need for appropriate management measures to reduce heavy metal pollution and ensure the maintenance of ecosystem health and biodiversity. This study could provide a baseline for future investigations into the estuary's heavy metal contamination and its potential impact on the ecosystem's biota.