Over the course of 63 days, the mineralization and dissipation of 14C-ring labelled carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl-methylcarbamate), one of the highly toxic N-methyl carbamate pesticides, in an untreated Vertisol Moroccan soil used for sugar beet cultivation was studied in the lab. The experiment was carried out in both flooded and dry conditions. The 14CO2 production from soil amended with U-ring14C-carbofuran was monitored to determine carbofuran mineralization. Higher rates of 14C-carbofuran mineralization were observed in both conditions. Mineralization was greater in wet conditions (19.2 percent) than in flooded conditions (12.4 percent ). The soil extractable pesticide residues decreased over time in both conditions, while the bound residues gradually increased. In flooded conditions, the rate of extractable 14C-activity disappearance was much higher than in non-flooded conditions. Under flooded and wet conditions, 15.8% and 31% of the applied dose were retrieved as extractable residues at the end of the experiment, respectively. In flooded soil, soil bound residues accounted for 33.3 percent of the applied dose, while non-flooded soil accounted for 29.1 percent. Organic volatiles were much more abundant in flooded soil (18.2 percent), compared to 5.6 percent in non-flooded soil. Carbofuran phenol was the key degradation product. The findings show that carbofuran is mineralized more quickly in moist soils than in flooded soils, and that there is a significant difference in the rate of degradation of the material in moist and flooded soils.
Author (s) Details
Laboratory of Pesticides residues, UR Research on Nuclear Techniques, Environment and Quality, Regional Center of Agricultural Research, 78, Bd Mohamed Ben Abdellah, 90010 Tangier, Morocco.
National Institute for Agricultural Research, Av. Ennasr, Rabat, P.O.Box: 415, Morocco.
University Abdel Malik Essaadi, Faculty of Science and Technology, Ancienne Route de l’Aéroport, Km 10, Ziaten. BP: 416. Tanger, Morocco.
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