| The radiotracing technique, environmental biotechniques, atom absorption spectrum, HPLC and TE techniques were used to investigate the effect of metal accumulation and distribution under interaction of metal mixture on the sublethal concentration and the physiological toxicity, gene toxicity and morphological damage caused by the metal mixture. The significance of this research is that to understand the effects of sublethal metal toxicity on the fish and how such effects could be set up as molecular biomarkers to indicate the exposure of fish to low metal concentrations. The research findings can be used as a scientific basis for making standards and law to prevent or eliminate the hazards of metals to the aquatic ecosystem.The results demonstrated that accumulation of copper and lead was related to metallic species and concentration, and as well as fish tissues. The accumulation of copper was affected greatly by the action of the Cadmium where as for lead; both Zinc and Cadmium or their combined action influenced its accumulation. The effects became more significant with the increase of the metal concentration. The accumulation of the copper and lead decreased in gill in the mixture-metal interaction, but increased in the liver, copper in addition, increased in the brain. The metal mixture could not affect the accumulation of both Cu and Pb in the muscle. The accumulation of copper in the tissues followed the order: liver>gill >brain>muscle. For the lead the order was liver>gill>muscle. The hypothesis was firstly proposed that combined the surface competition theory and MT induction theory, which could be used to explain perfectly the metal accumulation under the interaction of mixture-metal. The metal accumulation under the interaction of the mixture-metal was dominantly controlled by the surface competition in the gill and by the MT induction theory in the liver.Na- & K-ATPase activities in the tissues' were inhibited by the exposure of the metal mixture. There was significant negative linear relationship between Na- & K-ATPase activity and the exposure concentration (brain: Y=0.688X+1.27, F=21.0,0, gill: Y=-0.874X+2.85, F=76.5, liver: Y=-0.492X+1.99, F=41.2), when the exposureconcentration was from 0.077mg/L to 1.16mg/L. The sensitivity of Na-& K-ATPase activity in the tissues' was brain (EC50 =0.92mg/L)>gill (EC50 =1.63mg/L)>liver (EC50 =2.02mg/L) for the metal mixture.The metal mixture also induced the lipid superoxide in the Carassius auratus tissues. The results of the LPO between the single and metal mixture exposure revealed that the LPO followed the order hi the gill: metal mixture gill (EC50=0.21mg/L) >liver (EC50=1.42mg/L). There were dose and time responses in the LPO. The exponential relation was found between the MDA (LPO product) content and exposure concentration, when the exposure concentration was from 0.00 to 0.54mg/L. The equations for the gill, brain and liver were Y=e-2-87X+0687, Y=e-"lx+1 M, Y=e"2-19X+0115 respectively. There was a positive linear relation between the MDA content and exposure time, during the 7 days at 0.54mg/L. The equation for the gill, brain and liver was Y=0.830X+1.62, Y=0.815X+2.11 and Y=0.301X+0.892 respectively.Isozyme techniques were used to analyze the induction of the SOD and POD in the Carassius auratus by the metal mixture. It was found that the SOD activity in the tissues followed the order: liver>gill>brain where as the order for POD activity was: gill>liver>brain. there were negative linear relationship between the SOD and POD activity and the MDA content in their respective tissues, When the metal mixture exposure concentration ranged from 0.00-0.54mg/L. The brightness and appearance of the SOD band on the position 1 or the brightness of the POD band in the pos...
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