الفهرس 
Introduction
AtrazineOnly 14 pages are availabe for public view
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Abstract
This investigation was carried out at the aim of the isolation some of atrazine and cadusafos-degrading bacteria and study the persistence of pesticides in liquid media and soil inoculated with selected bacteria. Two isolates A8 identified as Bacillus megaterium and R2 identified as Arthrobacter uratoxydans were isolated from soil enrichment with pesticides. They are chosen for their high ability to utilize 100 and 500 ppm of atrazine as a sole source of carbon and/or nitrogen as well as a 100 and 300 ppm of cadusafos as a sole source of carbon and/or phosphorus.
In liquid mineral salts medium, the persistence of atrazine after 30 days was 54.2% for B. megaterium and 66% for A. uratoxydans. The mixed culture containing two isolates was more effective on atrazine depletion; persistent of atrazine was just 29% within 30 days. And the atrazine degrading enzymes were induced. In soil, the residue of atrazine from initial concentration 50 ppm, in non-sterilized soil reached to 12 ppm in inoculated soil and 37.65 ppm for un-inoculated soil after 45 days. While the residue of atrazine in inoculated sterilized-soil was 15 ppm and 42.5 ppm in un-inoculated sterilized-soil. That was concurrent with high microbial activity for inoculated soil. Three metabolites, deisopropyl-atrazine, deethylatrazine and deisopropyldeethylatrazine, were result from degradation of herbicide atrazine in liquid media and soil by mixed culture. The biological test to evaluate atrazine degradation showed that, the time required for remediation of atrazine is less than that required for germination of leguminous plant. The persistence of cadusafos in liquid mineral salts media after 21 days of treatment reached to 44.9% by A. uratoxydans, 57% for B. megaterium and only 13.6% for mixed culture. While in soil, The dissipation of cadusafos in non-inoculated soil was 15.6 ppm of initial concentration 50 ppm within 45 days. And it was 30.5 ppm in inoculated soil.