Persistence And Degradation Of Carbofuran In Soil And In Microbial Cultures Without And With Added Salts

The stability of U-phenyl-¹⁴ C-carbofuran in a flooded alluvial soil amended with a mixture of NaCl + CaCl₂ + MgSO₄ (3:2:1) to raise the salinity to 4, 8 and 16 dS/m was studied. The soil persistence of carbofuran was not affected by the presence of salts even at 16 dS/m. Soil enrichment cultures from both salt-amended and unamended soil retreated with carbofuran effected more rapid degradation of carbofuran in a mineral medium than did the respective soil suspension not exposed to carbofuran hefore. The dominant bacteria isolated included Bacillus sp. and Micrococcus sp. from the soil amended with 8 dS/m and two strains of Arthrobacter from the soil amended with 16 dS/m. Bacillus sp. was the most effective in degrading carbofuran. Interestingly, the Arthrobacter sp., isolated from the soil amended with salts at 16 dS/m effected more rapid degradation of carbofuran in the presence of NaCl + CaCl₂ + MgSO₄ than in their absence. Hydrolysis with concomitant accumulation of 7-phenol was the primary pathway in the bacterial degradation of carbofuran.