Specific Impact Of Soil Microorganisms On Removing Heavy Metals From Contaminated Media
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Abstract
The laboratory experiment was conducted in the lab. at Agriculture College of the / University of Basrah using soil taken from Abu Al-Khasib area alluvial clay soil (Silty clay). The study included several local isolates of the fungi and bacteria isolate to identify specific phosphate dissolving fungi (Aspergillus niger) using potato dextrose agar media and bacteria (Bacillus Polymyxa) using pikovisky media.
isolated fungi and bacteria inoculated on proth media contaminated with heavy matele (cadimun and lead) speartly cadmium at levels (0,5,10,20,50) ppm and lead at levels (0,5,10,25)ppm and incubated for different periods (7,14,21,28) days.
The results showed the effects of different cadmium levels on the number of fungi colonies in different incubation periods and the best increase in the number of fungi in the Cd. level (20ppm) and incubation periods (21, 28) days. While a noticeable decrease in the (50ppm) in the same incubation periods (21,28)days.
The beast increase in the number of fungi colonies was in the pb level (25ppm) at the periods (21&28) days. Moreover, decrease in fungi colony numbers at the level (0,5,10)ppm in incubation periods (7,14,21). Cadmium caused an increase in the Bacillus colonies number at the (0ppm) level in all incubation periods. In contrast, there was a decline in the number of colonies (10,20,50)ppm. Effects of lead levels the highest increase in the number of colonies at the incubation periods (7) days and a noticeable decrease in the number of bacterial colonies at the (10,25) ppm at (7,28)days.
The highest Aspergillus niger tolerance index % was at (20 ppm) Cd levels and (21) days incubation. Most substantial tolerance index % for Aspergillus niger at (25ppm) pb level and (14) days of incubation.
The best Bacillus Polymyxa bacterial tolerance index % at the (20ppm) to Cd. level at (28) days of incubation. And the beast tolerance index % for (5&10) ppm of lead levels in (21)days of incubation.