Heavy metal concentrations in the estuarine core sediments recovered from the part of the coastal Cauvery Delta, Bay of Bengal, India

Abstract

The manuscript investigates the sediment textures, heavy metals, and magnetic susceptibility analysis of the Cauvery and Vettar core sediments to affirm the pollution status by coupling environmental magnetism and geochemical studies. Pollution indices such as the Geoaccumulation Index, enrichment factors, and contamination factors were used to evaluate the pollution status. Fastidious inspection of the textural characteristics of the core sediments implies that the Cauvery core chiefly comprises sand and silt, whereas Vettar core sediments consist of silt and clay compositions. The magnetic susceptibility of the Vettar sediments implies higher magnetic contents than the Cauvery sediments. Notably, the profound inquisition illustrates the mean concentration of the studied heavy metal concentrations (Fe, Cu, Cr, Zn, Pb, Ni) for both core sediments did not exceed the mean world sediments and the Earth’s crust standards. Employing the pollution indices reflects the concentration of heavy metals in both core sediments, which infers environmental contamination. The result implies that the Vettar estuarine sediments show a mixed nature of magnetic grains (maghemite minerals) coupled with clay and silt composition, followed by the Cauvery estuarine sediments showing slighter magnetic susceptibility, which reflects that the Cauvery core sediments are less prone to pollution. However, the non-superparamagnetic grains indicate primarily sand and minor silt composition, reflecting ferromagnetic lithogenic minerals such as magnetite and hematite magnetic components. The statistical techniques establish the relationship between the magnetic susceptibility of χlf value higher in the core sediments depending on the heavy metal contents, clay, and organic matter.