A comparison of metal levels and antioxidant enzymes in freshwater snails, Lymnaea natalensis, exposed to sediment and water collected from Wright Dam and Lower Mguza Dam, Bulawayo, Zimbabwe
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Date
2010-08
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier Inc.
Abstract
We compared the bioaccumulation of lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu), nickel (Ni) and
iron (Fe) with antioxidant enzyme activity in tissues of the snails, Lymnaea natalensis, exposed to
elements of two differently polluted dams. 45 snails were exposed to sediment and water collected
from Wight Dam (reference) whilst another 45 snails were also exposed to sediment and water
collected from Lower Mguza Dam (polluted dam). Except for Fe in sediment and Pb in water, metal
concentrations were statistically higher in sediment and water collected from Lower Mguza Dam. Lead,
Cd and Zn were two times higher in tissues of snails exposed to Lower Mguza Dam elements. On one
hand, superoxide dismutase (SOD), diphosphotriphosphodiaphorase (DTD) and catalase (CAT) activities
were significantly lower whilst malondialdehyde (MDA) levels were significantly higher in tissues of
snails exposed to Lower Mguza Dam sediment and water. On the other hand, selenium-dependent
glutathione peroxidase (Se-GPX) activity was significantly elevated in tissues of snails exposed to Lower
Mguza Dam sediment and water. Snails exposed to Lower Mguza Dam elements seem to have
responded to pollution by increasing CAT and Se-GPX specific activity in an effort to detoxify peroxides
produced as a result of metal induced oxidative stress.
Description
Ecotoxicology and Environmental Safety
Keywords
Antioxidant enzymes, Heavy metals, Lymnaea natalensis
Citation
Siwela, a H., Nyathi, C.B. & Naik, Y.S., 2009. Metal accumulation and antioxidant enzyme activity in C. gariepinus, catfish, and O. mossambicus, tilapia, collected from Lower Mguza and Wright Dams, Zimbabwe. Bulletin of environmental contamination and toxicology, 83(5), pp.648–51.