الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Heavy metal pollution represent environmental problem due to its toxic effects and their accumulation throughout the food chain leading to serious ecological and health problems. The main sources of heavy metal pollution are mining, milling and surface finishing industries, which might discharging a variety of toxic metals such as Cd+2, Cu+2, Ni+2, Zn+2, Co+2 and pb+2 into the environment. Heavy metals include lead, chromium, mercury, uranium, selenium, zinc, arsenic, cadmium, silver, gold, and nickel cause pollution in the aquatic system and become a serious threat today and of great environmental concern as they are nonbiodegradable and thus persistent.
The present study concludes that soil irrigated with waste water contains tolerant fungi due to their physiological adaptation and they have greater potential for remediation by virtue of their aggressive growth; greater biomass, production and extensive hyphae reach in soil. Moreover, fungi have been widely used in bioremediation of industrially polluted soils and waters, specifically in the removal of hydrocarbons and heavy metals. The results obtained confirmed that the response of isolates to heavy metals depended on the metal tested, its concentration in the medium and on the isolate under consideration. The soil samples were collected from different distances of Chinese forest region, the fungal species were isolated and Identified from each soil samples. Seven isolates forming the grown dominant population were selected. According to the appearance features of the grown colonies, Aspergillus niger, Aspergillus flavus., Penicillium sp., Aspergillus fumigatus, Fusarium sp., Trichoderma sp. and Rhizopus isolates formed the highest population.
The present study shows that the soil samples of chines forest region in Sadat city locations showed higher concentration of heavy metals. The isolated fungi of studied sites were more tolerant to heavy metals. Our conclusion indicates that fungal population isolated from heavy metal contaminated sites has the ability to resist higher concentration of metals. A comparative level of metal resistance was also shown by filamentous fungi originated from unpolluted sites. The tolerance and resistance of the isolates depended much more on the fungus tested than on the site of its isolation. This variation may be explained by the development of tolerance and adaptation of the fungi to heavy metals. Aspergillus and Trichoderma sp was the most resistance to all the metals tested, which make them promising candidates for further investigations regarding their ability to remove metals from contaminated environment. The present study indicates that isolated fungi of contaminated soils can be used as bioremediation agents.
The results in tables (47, 48, 49, 50, 51 & 52) showed the absorption capacity or amounts of Cu, Co and Ni by Aspergillas niger was the highest absorption rate in comparison with Trichoderma isolates. The result revealed that at concentration 30, 60, 90 ppm of cupper, the absorption capacity by using Aspergillus niger were 22.89, 36.10 & 50.11 respectively but in case of Trichoderma isolate, were 21.69, 34.36 & 48.78 respectively.
The results in tables (47, 48, 49, 50, 51 & 52) showed Absorbed percentage or removal efficiency (Re) of Cupper, Nikle & Coblet by using Aspergillus niger were highest rate thon by Trichoderma isolates. At concentrations 30, 60 & 90 ppm of Cupper the absorbed percentage were 76.3%, 60.06% & and 55.67% But in case of Trichoderma were 72.3%, 57.31% & 54.20% respectively. However at concentration 30, 60, 90 ppm of Coblet, the absorbed percentage by using Aspergillus were higher, 86.73%, 70.38% & 67.12% But in case of Trichoderma were 83.56% 69.31% & 66.43% respcitvly. Also at concentration. 30, 60 & 90 ppm of Nickel, the absorbed percentage by using Aspergillas niger were 82.70%, 66.40% & 60.86%, But in case of Trichoderma were 32.96%, 50.18% & 53.60% respectively.
The results in tables ( 53, 54 & 55) obtained in this study revealed that the absorption capacity & removal efficiency of heavy metals Cu, Co & Ni were increased in presence of oxalic acid in the fungal medium. At concentration, 30, 60, 90 ppm of Cupper in presence of oxalic acid, the absorption capacity were 24.78, 44.09 & 50.39 ppm & were high in compression of absorption capacity in absence of oxalic acid, were 22.89, 36.10 & 50.11 ppm.