Metal Levels and Antioxidant Enzyme Activities in Freshwater Snails Exposed to Sediments From Polluted and Pristine Dams in Zimbabwe
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Date
2013-03-12
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Abstract
The aim of this study was to determine the metal and antioxidant enzyme activities (AGE's) in the freshwater snail Lymnaea natalensis, exposed to sediments form a polluted (Umguza) and pristine (Wright) dams around Bulawayo City, Zimbabwe with a view to developing a biomarker of freshwater pollution. Adult lab reared snails (10-15 mm) were exposed for 4 weeks to water and sediment cofiected from 4 different sites of Umguza Dam (a sink of domestic and industrial effluent) and Wright Dam (privately owned -and considered to be relatively pristine). Antioxidant.
enzymes, heavy metals and malondia1dehyde (MDA) analyses were performed using the S-9 fraction of whole snail soft tissue. Catalase and glutathione peroxidase activities were significantly elevated in snails exposed to Umguza Dam water and sediment (Student t-test, p < 0.01 and p < 0.001) when compared to snails exposed to Wright Dam. DT- diaphorase activity was significantly reduced in snails exposed to Umguza Dam water and sediment (p < 0.001) when compared to snails exposed to Wright Dam water and sediment. Snails exposed to Umguza Dam water and
sediment bad a higher total metal load compared to those exposed to Wright Dam elements and the MDA levels were correspondingly elevated in snails exposed to polluted water and sediment (p < 0.01). The higher MDA levels and altered AGE activities suggest that the snails exposed to Umguza Dam elements are under higher oxidative stress.
Description
Presented at the Fourth International Conference of the Society for Free Radical Research - Africa in October 2003.
Keywords
Snails, Antioxidant Enzymes, Water Pollution