African Journal of Soil Science

African Journal of Soil Science ISSN 2375-088X Vol. 7 (5), pp. 001-007, May, 2019. © International Scholars Journals

Full Length Research Paper

Biodegradation and dissipation of ¹⁴C-carbofuran in clay soil from Loukkos perimeter, Northwestern Morocco

BENICHA Mohamed¹*, MRABET Rachid² and AZMANI Amina³

¹Laboratory of Pesticides residues, UR research on nuclear techniques, environment and quality, Regional Center of Agronomic research, 78, Bd Mohamed Ben Abdellah, 90010 Tangier, Morocco.

²Regional Center of Agronomic research, 78, Bd Mohamed Ben Abdellah, 90010 Tangier, Morocco.

³University Abdel Malik Essaadi, Faculty of Science and Technology, Ancienne Route de l'Aéroport, Km 10, Ziaten. BP: 416. Tanger – Maroc.

Accepted 21 March, 2019

Abstract

Mineralization and dissipation of ¹⁴C-ring labeled 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 under laboratory conditions over a period of 63 days. The experiment was conducted in flooded and non-flooded conditions. Carbofuran mineralization was determined by monitoring the ¹⁴CO₂ production from soil amended with U-ring¹⁴C-carbofuran. Under both conditions, higher mineralization rates of ¹⁴C-carbofuran were observed. The extent of mineralization being more in moist (19.2%) than in flooded conditions (12.4%). In both conditions, the soil extractable pesticide residues decreased with time, while the bound residues gradually increased. The extractable ¹⁴C-activity disappearance rate was much higher in flooded than in non-flooded conditions. At the end of the experiment, 15.8% and 31% of applied dose were recovered as extractable residues under flooded and moist conditions respectively. Soil bound residues were formed to the extent of 33.3% of the applied dose in flooded soil, while 29.1% was formed in non-flooded soil. The amount of the organic volatiles was much higher in flooded condition (18.2%), as compared to 5.6% in non-flooded soil. The main degradation product formed was carbofuran phenol.

Key words: Carbofuran, mineralization, degradation, volatilization, ¹⁴C, biodegradation.