Decomposition of 14C-labelled carbofuran in a black tropical soil under laboratory conditions

Abstract

The relative importance of microorganisms in determining losses of carbofuran in soils was investigated under laboratory conditions using labelled [ 14C]carbofuran with soil samples collected from rice fields ( Oryza sativa). Experiments were conducted in the following four conditions: 1. non-sterile and non-flooded (NSNF); 2. non-sterile and flooded (NSF); 3. sterile and non-flooded (SNF); 4. sterile and flooded (SF). In SF and SNF soils >75% of the added carbofuran was recovered as residues after 60 days whereas in NSF and NSNF soils >75% of the added carbofuran was metabolized during the same period. In SF, SNF and NSNF soils only traces of 3-OH carbofuran was found as a metabolite. However. in SF and SNF soils no other metabolite was detected, while in NSNF as well as NSF soils varying amounts of 3-keto carbofuran and carbofuran-7-phenol were detected as metabolites during incubation. 3-OH carbofuran phenol and 3-keto carbofuran phenol were not detected.