Gado Tchangbedji

Bioaccumulation de certains éléments métalliques dans les produits maraîchers cultivés sur les sols urbains le long de l'autoroute Lomé- Aného, Sud Togo

Abstract Several metallic elements were analyzed by ICP—AES in 10 vegetable species cultivated in market—gardening agriculture in Lomé and its suburban, along the highway Lomé-Aného, Togo. The results showed a high accumulation of these metallic elements both in the vegetables and in the soils. Leaf vegetables accumulated higher concentration of these metallic elements than bulb or tuber vegetables. These metals could result from the air pollution due to the intense industrial activity and the high road traffic in this site and from chemical fertilizers and pesticides used by the market-gardeners. This survey stated that the metallic elements from air, could accumulate in the legumes by foliar absorption. Furthermore, this study especially pointed out that legumes cultivated in this area could be improper for human consumption.

Clay and Soil Photolysis of the Pesticides Mesotrione and Metsulfuron Methyl

Photolysis may represent an important degradation process of pollutants at the surface of soil. In the present work, we report a detailed study on the degradation of two pesticides: mesotrione and metsulfuron methyl using a sunlight simulator. In a first step, we studied the photochemical behaviour at the surface of clays from the kinetic as well as from the analytical point of view. In both cases, the quantum yields were found to be higher when compared to those obtained in aqueous solutions. The effect of iron(III), water, and humic substances contents was studied. In the former cases, an increase of the degradation rate was observed while an inhibition was observed with the latter owing to a filter effect phenomenon. In a second step, we studied the photodegradation at the surface of natural soil and identified the generated byproducts. They appear to mainly arise from photohydrolysis process.