Investigation of heavy metal concentrations in sea food from three selected landing centers of Chennai coast

Abstract

A polluted marine environment may end in food chain and pose risk to public health. A study was undertaken to analyze the level of heavy metal concentrations chromium (Cr), copper (Cu), Iron (Fe), zinc (Zn), Lead (Pb), nickel (Ni), manganese (Mn), lithium (Li) and titanium (Ti) in sea foods harvested from fish landing centres Ennore, Royapuram and Pattinapakkam located in Chennai. The samples were analyzed using inductively coupled plasma optical emission spectrometry method (ICP-OES). The highest average concentration of heavy metals was recorded from Ennore (10.70 mg kg-1) and in crabs (11.7 mg kg-1) among the sea foods. Ni was highest and Fe was lowest recorded from all the study sites. Chi square analysis revealed no significant difference (P > 0.05) between the study areas and seafood varieties. Cr, Mn, Ni and Zn exceeded and Cu, Fe and Pb were within the permissible limits of WHO (1989) for human consumption. Introduction Heavy metal is a metallic element with high atomic weight which can damage living things at low concentrations and tend to accumulate in the food chain [1]. Some heavy metals have essential roles for human health and forms an integral part of numerous enzymes. Heavy metal pollution has become a worldwide concern due to the increasing levels of pollution and its obvious impacts on human health. These are of great concern from the public health point of view, and being environmental pollutants it can occur naturally in the environment and can come from industrial (e.g. mining, metallurgical, incineration, pesticide etc.) or agricultural sources (e.g. pesticide and fertilizers use). Almost all pollutants find their ways finally to sea as the ultimate sink. These contaminants are highly toxic and may accumulate in seafood, whose consumption can represent an important route of human exposure to these harmful substances and ultimately threaten human health. Marine coastal ecosystems could therefore be endangered by pollutants, such as heavy metals, pesticides and antifoulants that could be easily detected in the water column or in the sediment of harbours and estuaries [2]. Heavy metals, in general, are not biodegradable, have long biological half lives and also have the potential for accumulation in the different body parts leading to unwanted side effects [3]. Untreated urban and industrial wastewater effluents cause a variety of health and environmental concerns, when released into receiving water bodies. Coastal belts are highly populated and urbanized with industries. Marine food such as fish, prawn, crab and mussel are delicacies and form an important staple part of daily food. The tendency of heavy metals to get accumulated in marine animals is of scientific interest in heavy metal chemistry. The bioavailability of trace metals is the key factor determining tissue metal levels in the marine biota. Trace metal uptake occurs directly from surrounding marine water across the permeable body surface and from food along with the seawater to the gut [4]. Fish, crab, prawn and squids form an important link as possible transfer media to human beings. Information on the level of heavy metal pollution in coastal environment is important as they cause serious environmental health hazards [5, 6, 7] .