Study of degradation of endosulfan residues in coffee rusk (Coffea arabica L.)

The persistence was studied of the residue of cyclodiene pesticide endosulfan in coffee husks for different periods of application, whilst seeking to control the coffee-berry borer Hypothenemus hampei. The influence of coffee husks composting on thefinal amount of residues being inoculated by the soil microorganisms was also studied. The employed method in the analyses was adapted from Mitchell (1976) by Lemes et al. (1993), by the extraction with acetonitrile and purification by partition in a dichloromethane-hexane mixture followed by a florisil column chromatography clean-up concentration and GC determination with ECD. The limit of detection was 0.03 mg/kg (ppm) to alpha and beta endosulfan and 0.04 mg/kg (ppm) to endosulfan sulfate metabolite. The recoveries of fortified samples ranged from 80.55 to 112.03 percent. In composting the coffee husks, there was a predominance of the fungi Aspergillus, Penicillium, Fusarium and Rhizopus. The microbial population increased in simultaneous degradation of residues of endosulfan isomers alpha and beta, and endosulfan sulfate as well, in a second order exponential decay function.