Geochemical distribution of heavy metals in sediments from sewage fed fish ponds from Kolkata Wetlands, India

Abstract

Kolkata wetlands are the largest sewage fed wetlands in the world. They have been used for aquaculture since 1960. Geochemical distribution of heavy metals (Cr, Cu, Mn, Fe, Zn, Pb, Ni and Al) has been studied in surface sediments using single and sequential extractions techniques. The metal concentrations in sediments were in the following order: Fe4Al4Mn4Zn4Cu4Pb4Cr4Ni, and the average concentrations were 29 mg g À 1 , 54 mg gdry weights for Cr, Cu, Mn, Fe, Zn, Pb, Ni and Al, respectively. Water-soluble percentages of the trace elements are quite low (50.01 -3.75%) but in the presence of chelating agents in the sediments increase the bioavailability of trace elements (2 -58%). About 40% of trace elements are in the stable form as a residual fraction of the sediment and more than 50% (nonresidual fraction) metal contamination of the Kolkata wetland sediments were from anthropogenic inputs. The contamination risks of Cr, Mn, Zn, Pb, and Ni are high as their potential availabilities are 70.96%, 58.01%, 63.13%, 55.62%, and 52.15% respectively. The mean concentration of most of the heavy metals in sediments does not exceed the recommended reference values. Zinc and lead concentrations were greater than background level and Interim Sediment Quality Guidelines but lower than Probable Effect Level. Therefore a regular program for monitoring the distribution of heavy metals in water, sediments and biota should be imposed on sewage fed fish ponds of the Kolkata wetland ecosystem.

Nutritional value and bioaccumulation of heavy metals in muscle tissues of five commercially important marine fish species from the Red Sea

“…Manganese concentrations in this study were similar to those reported by Ahmed and Naim (2008) . Kumar et al (2011) recorded Mn concentrations (2.9 μg/g) in several fish species collected from Indian waters. A concentration of 0.5 mg/kg Mn in marine fish species gathered from Kochi Waters has been documented by Sankar et al (2006) .…”

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“…Though preventive measures have been taken to reduce the input of trace metals into oceans, rivers and estuaries, accumulation in the different aquatic systems have been reported even today (Kumar et al, 2010(Kumar et al, , 2011Dural and Bickici, 2010;Paller and Litterell, 2007). Industrial wastes and mining can create a potential source of heavy metal pollution in the aquatic environment (Gumgum et al, 1994).…”

Health Concerns Related to Consumption of Fish from Anzali Wetland

“…Khosravi et al reported the high accumulation of this metal in Anzali wetland deposits [13]. Also according to Ashja Ardalan et al Zn and Pb concentrations in the deposits, water and soft tissues of Anadonta cygnea in the Anzali wetland was higher and lower than a Source: [41,42].…”