Abstract

CONCENTRATIONS OF HEAVY METALS IN EDIBLE CRABS FROM TAMIL NADU COAST, SOUTH INDIA

V. Ramesh, S. Sarojini and P. Senthilkumaar*

Abstract

In order to compare with and assess the metal-accumulating ability of the two different edible crab belonging to the genus of Portunus (Portunus pelagicus and Portunus sanguinolentus), the concentrations of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb) and zinc (Zn) of ambient sea water and the surface sea sediment were investigated. The samples were simultaneously collected from Pudhucherry and Velankanni coastal area located in southern India during September – October 2014. The highest bioconcentration factors of Cd, Cr, Cu, Fe, Ni, Pb and Zn in edible crabs appeared at sampling location Velankanni than Pudhucherry. Similar results were also recorded in the water and sediment samples which is proved that the Velankanni coast is contaminated by the trace metals due to the fishing harbor waste and the waste from large beachgoer’s/ mass visit/ holy dipping. Apart from that, the sampling locations received large amount of different waste such as municipal sewage, industrial, shipyard, agricultural and ballast water waste which contributed higher trace metal pollution in these regions. The orders of decreasing trace metal values were: Portunus sanguinolentus > Portunus pelagicus > Sea sediment > Sea water. The metal contents of edible crabs such as Cd, Cr, Cu, Fe, Ne Pb and Zn concentrations were between 0.15 – 0.22, 0.06 – 0.12, 0.80 – 0.96, 5.54 – 7.34, 0.04 – 0.12, 0.10 – 0.18 and 0.94 – 1.84 mg kg-1, respectively. In fact, Portunus crabs can accumulate more trace metals which reflects the conditions of the ambient environment. These phenomena, as well as the fact that the crabs are able to accumulate relatively high levels of trace metals suggest that these crabs are potential bio-monitors of metal pollutions in coastal ecosystems.

Keywords: Portunus sanguinolentus, Portunus pelagicus, Heavy metals.