Persistencia de malation y deltametrin en productos almacenados

Abstract

Kinetics degradation of deltamethrin and malathion in stored bean, rice and field pea was studied at normal and high application doses, on packed foods (malathion 60 mg/m² and 240 mg/m²; deltamethrin 12,5 mg/m² and 50 mg/m²); and to bulk (malathion 6 mg/kg and 24 mg/kg; deltamethrin 1 mg/kg and 4 mg/kg). In the case of field pea the applications were carried out on the packed food only. Samplings were taken at 62, 85 and 89 days in the cases of bean, rice and field pea for each one, furthermore residues analysis for both insecticides in a simultaneous way were made, by means of maceration with dichloromethane. The determination was carried out by gas chromatography, with NPD detector (malathion) and ECD detector (deltamethrin). Malathion and deltamethrin residues in packed foods had not toxicologically significance, for all treatments. Residues tests of bulk grains were toxicological significant. Malathion residues in bean were inferior to the National Maximum Residues Limits (NMRL) after 16 and 33 days of applied at both lower and higher doses, and for deltamethrin, the corresponding times were 9 and 33 days. In rice experiments, malathion residues were inferior to the NMRL only 85 days after application with the lowest dose and they did not descend to the corresponding value during this time, when the higher dose was applied. In the case of deltamethrin times were 7 and 85 days respectively.