Mohamed Nasr Leithy <br/><br/>
effect of heavy metals on microbial activity insome ecosystems /  
 تاثير المعادن الثقيلة على النشاط الميكروبى فى بعض الاوساط البيئية 
Mohamed Nasr Leithy ; Supervised Mohamed Zakaria Sedik , Zahira Said Tawfik 
 - Cairo :   Mohamed Nasr Leithy ,   2006 
 - 133p :   ill ;   25cm 
<br/><br/>Thesis (PH.D.) - Cairo University - Faculty Of Agriculture - Department Of Microbiology 
<br/><br/> The effect of four metal concentrations , as well as , six Gamma - irradiation doses on the activity of cellulase , urease and dehydrogenase was determinedApplication of heavy metals at any rate caused noticeable reduction in their activity depending upon the metal type and concentrationEven at the low concentration , Cr6+followed by Hg2+had the most harmful effect on the enzymatic activities , while Pb2+showed the least toxicitySoil exposure to Gamma - irradiation differently affected the enzymatic activitiesThis varied from stimulating effect on urease to suppressive one on dehydrogenaseGenerally , the high doses of - rays inhibited the activity of the three enzymes and dehydrogenase proved to be the most susceptible enzyme toward radiation 
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<br/><br/><label>Subjects--Index Terms: </label>Heavymetals Organic motter soil pollution