Study on Degradation Processes of 14C-Carbofuran in Soil from Northwest Morocco as Influenced by Soil Water Content, Temperature and Microbial Activity | Chapter 2 | Current Topics on Chemistry and Biochemistry Vol. 4

 

 In order to forecast the destiny of carbofuran in soil and the environment, this study was carried out to determine the effects of soil temperature, moisture, and microbial activity on the mineralization and dissipation rate of carbofuran on a typical sugar beet clayey soil in the Loukkos area (Northwest Morocco). The findings of the incubation studies showed that the soil's water content and temperature have a significant influence on the rates of carbofuran mineralization and dissipation, and that autoclaving the soil significantly extended the insecticide's half-life. The rates of mineralization and degradation in non-autoclaved soil increased as soil moisture content and temperature climbed. Carbofuran half-lives in natural soil ranged from 26 to more than 90 days, and dissipation rates were first-order kinetic in nature. The main pathways for carbofuran degradation—chemical and microbial—are greatly influenced by the temperature and moisture content of the soil. But in the autoclaved soil, the half-life increased 3.6 times, from 39 to 142 days. Mineralization was avoided by autoclaving, proving the importance of bacteria in the pesticide's decomposition procedure. However, since bound residues accumulated in the autoclaved soil in significant amounts (19%), it suggests that the pesticide was also broken down by non-biological mechanisms. These results may have implications for insecticide risk assessment studies and the verification of pesticide dissipation models for clayey soils in sugar beet-growing regions of Morocco.

Author(s) Details:

Benicha Mohamed,
Pesticides Residues Laboratory, National Institute for Agricultural Research (INRA), 78, Bd Mohamed Ben Abdellah, 90010 Tangier, Morocco.

Mrabet Rachid,
National Institute for Agricultural Research (INRA), Rabat, Morocco.

Moussadek Rachid,
National Institute for Agricultural Research (INRA), Rabat, Morocco and  International Center for Agricultural Research in the Dry Areas (ICARDA), Rabat, Morocco.

Azmani Amina,
Faculty of Science and Technology, University Abdel Malik Essaadi, Route de l'Aéroport, Km 10, Ziaten BP: 416, Tangier, Morocco.

Please see the link here: https://stm.bookpi.org/CTCB-V4/article/view/7805  

Study on Biodegradation and Dissipation of 14C-Carbofuran in Clay Soil from Loukkos Perimeter, Northwestern Morocco | Chapter 8 | New Ideas Concerning Science and Technology Vol. 7

 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

Benicha Mohamed
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.

Mrabet Rachid
National Institute for Agricultural Research, Av. Ennasr, Rabat, P.O.Box: 415, Morocco.

Azmani Amina
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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