Studies on metal eco-toxicity of river Ravi stretch from Shahdera of head Baloki [Pakistan]
1999
Javed, M. (University of Agriculture, Faisalabad (Pakistan). Dept. of Zoology and Fisheries)
The effect of aquatic on the fate and dynamics of plankton including uptake and accumulation of heavy metals by the plankton and sediments has been studies with a view to assess its ill- effects on the river Ravi aquatic ecosystem. Eight heavy metals, viz. zinc, iron, magnesium, manganese, cadmium, leaf, nickel and mercury in sediments and plankton have shown direct relationships with the intensity of water pollution. Both plankton and sediments appeared as good indicators of freshwater contamination by metals in river ecosystem. The uptake and accumulation of all heavy metals (except iron) in both plankton and sediments were positively and significantly dependent upon metal toxicity in water. The accumulation of iron by sediments was negatively but significantly (P 0.01) dependent on iron in water. Among phytoplankton, Bumilleria, Cladophora, Chlorella, Fragilaria, Synedra, Scendesmus, Tabellaria and Zygnema indicated direct relationships with the intensity of pollution at highly polluted sites. Among zooplankton, Brachionus and Polyarthra were almost absent at highly polluted sampling stations. However, the genera, viz., Aphanizomenon, Bacillaria, Closterium, Cyclopedia, Cocconeis, Cosmarium, Chrococus, Denticulla, Euglena, Spirulina, Spirogyra and Volvox showed considerable tolerance against heavy metals toxicity. Keratella and Filinia appeared to be the tolerant genera against heavy metals toxicity while Cyclops and Philodena were found as the sensitive forms.
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