الفهرس 
Heavy metal pollutantsOnly 14 pages are availabe for public view
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Abstract
In the present investigation Gambusia affinis was chosen as an experimental animal because of its relative abundance and its great importance as it is considered among the natural functional unit in aquatic food web. an essential food itemfor many organisms as well as it causes some injuries to the cultured economic fish as they participated their food. Thus this investigation may stand as a trial to assess the role of temperature and joint action of copper and zinc on the survival and population intrinsic resistance of the chosen experimental fish as well as the effect of sublethal concentrations of copper on the embryological development of the fish and throw some light on the histochemical localization of copper and zinc in animal tissues. In order to accomplish the broad lines of the present program it can be concluded that the acclimation of the experimental fish was carried out using large sized glass aquaria (24 L capacity) for two weeks. Test solution of copper sulphate (CuS04.7H20) and zinc sulphate (ZnSo4.5H20) were prepared as stock solutions of 1000 mg/L. for each fresh dilutions prepared for each expirement and were made up by dechlorinated water. The toxicity tests were performed in three litre glass containers. The test solution was changed every 24 hours. Twenty individuals were placed per container. The test was repeated five times. Deaths of the test fish were recorded at equal intervals. Cumulative regression equations for the mortality of the test organism were adepted LTS0, LTl0o times could be estimated. The death deviations corresponding LTso, slope function (b) and the error of fitting the line could be recorded for each experiment. The present experiments have provided meaningful comparisons of lethality among heavy metal (copper and zinc) with different metal concentrations, it is clear that the toxicity ranges of LTso and LTloo are markedly variable among the two heavy metals. The order of toxicity of two heavy metals for test fish under normal conditions takes the following sequence Cu++> Zn++ with all concentrations. The present data clearly showed that the test fish was the most tolerant to the two metal tested at hypothermal conditions, also it is concluded that zinc is the least toxic metal for this fish and under all experimental conditions. On the other hand, from the obtained results it can be found that the higher temperature induced the greatest mixture toxicity to the test fish. As for the population intrinsic resistance of tested fish more pronounced at the hyperthermal conditions where the organisms have poor resistance with each mixture of different concentrations, since the obtained values of the death deviations corresponding 50% mortality showed high negative values at 15, 20 and 25•‹C. On contrary such values being positive at 5 and 10•‹C.