Use of benthic foraminifera as a proxy for monitoring heavy metal pollution in the Swarnamukhi estuary, southeast coast of India

Abstract

Benthic foraminiferal assemblages were surveyed as potential indicators of heavy metal pollution of sediments from Swarnamukhi estuary, southeast India. Grain size analysis indicated that the sediments were deposited under low energy conditions. Results of assessment by factor analysis and hierarchical cluster analysis showed relations among the heavy metals. The sediment pollution assessment was carried out using the Enrichment Factor (EF), and Pollution Load Index (PLI). The results showed significant seasonal variation in heavy metal concentrations, and several metals (e.g. Fe, Cr, Zn, Pb and Cd) had high abundance in the sediments. A total of 53 benthic foraminiferal species belonging to 20 genera and 3 suborders were recorded in the sediments. The effect of heavy metal pollution on foraminifera's species diversity was assessed. The assemblage changes and test abnormalities in foraminiferal species appeared to be proxies for evaluating environmental stresses. • Distribution and mobility of heavy metals in sediments collected from Swarnamukhi estuary were assessed. • A total of 53 species, 20 genera and 3 suborders according to their distribution was summarized. • Benthic foraminifera was used as a bio-indicator to evaluate the heavy metal pollution from the study area. • Benthic foraminiferal species and shell abnormalities were identified.