Biomonitoring of Metals in Freshwater Macrophytes and Benthic Organisms
Dr. K. Venkatesha Raju1, Dr. R. K. Somashekar2 and Dr. K. L. Prakash3
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The study focused on assessment of metal accumulation in certain aquatic macrophytes and benthic organisms to be used as biomonitors. The macrophytes and benthic organisms collected during April to May (2011) from river Cauvery, one of the main fresh water aquatic systems in the south of India. Microwave digested samples of discrete organs of macrophytes and benthic organisms were analyzed for metal concentration using AAS-6300. In macrophytes, among the eight metals investigated, six (Fe, Pb, Ni, Cr, Cu, and Cd) were showed higher degree of accumulation in root whereas, remaining (Mn and Zn) in stem and leaf respectively. Vallesnaria spiralis showed greatest potency to acumulate Fe, Mn and Cu, while Nymphe stellata showed the better ability to accumulate Zn and Cr. Cd was found only in Aquatic neam and Vallisnaria spiralis at downstream stations with very negligible concentration. Based on the accumulation level in macrophytes, the eight metals were arranged in the order of Fe> Mn> Zn> Cu> Pb> Cr> Ni > Cd. Among benthos, mollusca have showed a more accumulation capacity fallowed by crustacean and annelid. Bioaccumulation factor for benthos were observed in the sequence of Cu>Mn>Zn>Ni>Fe>Cr>Pb>Cd.