Accumulation and contamination of lead in different trophic levels of food chain in sewage-fed East Kolkata Wetland, West Bengal, India

Abstract

<strong>Abstract:</strong> Lead (Pb) is one of the common hazardous heavy metals posing severe toxicity problems in<br> aquaculture productivity and human health by bioaccumulation and biomagnification due to<br> its uncontrolled discharge into ecosystem in the age of modern industrialization and<br> agricultural growth. The study was carried out to monitor the contamination status of heavy<br> metal Pb in different trophic levels of the food chain in the ecosystem of sewage-fed East<br> Kolkata Wetland (EKWL), the plankton as primary producer which is consumed by highest<br> level consumer fish, Oreochromis niloticus, is the most abundant species in EKWL. The<br> concentration of Pb in water and accumulation in different trophic components of food<br> chain was analyzed by Atomic Absorption Spectrophotometer (AAS). Study shows that the<br> Pb concentration in water of EKWL was 0.573 mg/l and in plankton and small insects the<br> concentration of Pb was 0.0021 µg/mg and 0.0023µg/mg respectively. Accumulation of Pb<br> in different organ of studied fish (Oreochromis niloticus) was highest in intestine (0.0182<br> µg/mg) and lowest in fin (0.0004 µg/mg) with an order as intestine &gt; liver &gt; skin &gt; muscle<br> &gt; scale &gt; bone &gt; fin. Besides this, bioconcentration factor among different species in the<br> trophic level was also studied wherein plankton (0.037) and adult fishes (O. niloticus)<br> (0.325) showed lowest and highest values, respectively. The concentration of Pb in water<br> was alarming but in fish musels were below as per WHO permissible level. However, this<br> monitoring study should be frequent practice for the conservation of EKWL and proper<br> biosafety in aquaculture practices in order to control the Pb contamination as well as to save<br> environmental and human health from the serious hazardous problems of Pb contamination.