The effects of cadmium and zinc ions upon the longevity of two freshwater crustaceans, <i>Daphnia pulex</i> (de Geer) and <i>Cyclops fuscus</i> (Jurine) were examined at temperatures (8°C, 14°C, and 21°C). Winter collected speciments of both species were found to be more resistant than summer collected specimens. In both species Cd^++ was more resistant than Zn^++ and resistance to both metal ions was greater in <i>C.fuscus</i> than in <i>D.pulex</i>. Temperature has a synergistic effect on the toxicity of both metals to both species. The pH influence on the toxicity of Cd^++ and Zn^++ to <i>D.pulex</i> was examined. The toxicity of both metals increased with increasing acidity. Acidity alone was lethal to <i>D.pulex</i> with no Cd^++ or Zn^++ added. Cadmium and zinc were accumulated by <i>D.pulex</i> to high concentrations in proportion to time and concentration in solutions. Cadmium accumulations were lower than zinc. The major sites of accumulation, tested using Zn^65 were the gut, hepatopancreas and exoskeleton of <i>D.pulex</i>. The respiratory rate of <i>D.pulex</i> and <i>C.fuscus</i> were affected by the presence of CD^++ and Zn^++, but <i>D.pulex</i> was more affected than <i>C.fuscus</i>, and cadmium effect was generally more than zinc ions. The ultrastructural changes in the hepatopancreas of <i>D.pulex</i> were examined after exposure to cadmium ions. The hepatopancreatic cell was affected. Mitochondria were the most affected organelles.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:635672 |
| Date | January 1986 |
| Creators | Al-Ghamdi, H. S. H. H. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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