Degree of partitioning of heavy metals in different environmental segments of a sewage-fed fishery pond at East Kolkata Wetland, India – A case study.

Abstract

Anthropogenic activities like industrialization, unplanned urbanization, deforestation and profit oriented capitalism have resulted introduction of many undesirable substances into our immediate environment creating environmental degradation to a great extent. Normally, nature takes the responsibility of reducing the adverse effect of these substances through the operation of many physical, chemical and biological processes such that these substances can be partitioned in various biotic and a-biotic components of an environmental ecosystem. Present study is an attempt to highlight the extent of partitioning of some heavy metals in the compartments of water, sediments, macrophyte and fishes of a sewage-fed fishery pond in East Kolkata Wetland (EKW). Study distinctly revealed that all heavy metals show a common preference to be deposited on the sediments with higher values (28.5 to 56.5%) followed by macrophytes (20.3 to 35.4%), fishes (15.7 to 43.2%) and water (less than 1.0%). Similar types of partitioning might be observed in each higher plants and animals. As an example, in fishes, higher accumulation of heavy metals were in viscera (27.5 to 69.2%) followed by bone (4.6 to 47.7%), gill (8.1 to 30.6%) and least in flesh (< 1.0 to 19.0%). Again, in cases of toxic metals, it has been observed that flesh contains less than 1% and while the essential group of metals (Zn and Cr) showed comparatively higher degree of accumulation (11.3 to 19.5 %). Thus, the study evidently forecasted that re-distribution of heavy metals in large number of inter and intra compartments of natural biotic and abiotic agents, could be considered as the most effective mechanism for reducing the undesirable consequences of heavy metals or any toxic waste along with passage of time.