Characterization of carbofuran bound residues and the effect of ageing on their distribution and bioavailability in the soil of a sugar beet field in north-western Morocco

Abstract

This study was undertaken to investigate distribution, fractionation, bioavailability and remobilization characteristics of bound soil-aged carbofuran and the effect of ageing in clay soil in a typical field of sugar beet at Loukkos in northwest Morocco. Results indicate that initially there were high levels of bound residues (BR) in the humin fraction, which decreased with incubation time and ageing of the BR. While in the fulvic and humic acid fractions, the amount of BR increased with the ageing of the BR and occurred predominantly (60%) in the fulvic acid fraction. The possibility of the mineralization and release of BR with ageing was studied using fresh soil and an incubation period of 90 days. The results indicate that the ageing of the residues have a great influence on the remobilization and mineralization rates of carbofuran BR; 9.45 to 14.90% of the total BR was released as extractable residues, and 1.95 to 4.15% was mineralized depending on the age of the residues in soil and the soil-aged carbofuran BR. The incorporation of the residues in the humin fraction is considered to be a threat to the environment. On the other hand, the clear prevalence of residues in the fulvic and humic acid fractions, may have an important effect on their bioavailability and movement in soil. Moreover, the re-extractability of BR could pose a potential environmental risk. Consequently, the BR remobilized must be taken into account when assessing for registration processes the environmental risk of pesticides persisting in soils.

Soil Organic Matter Composition and pH as Factors Affecting Retention of Carbaryl, Carbofuran and Metolachlor in Soil

“…According to the literature [ 69 ], carbofuran predominantly incorporates into the recalcitrant humin fraction of SOM, constituting approximately 50% of the initial insecticide dose introduced into the soil. In a previous study [ 41 ], it was proven that retention of non-ionic carbamates on HA was much weaker (35.4% of carbofuran and 10.2% of carbaryl initial dose) than on more hydrophobic wheat-straw biochar.…”

Assessment of phytosanitary practices on the environment: case study potato of Loukkos (northwest Morocco)

“…It is characterized by intensive agriculture including horticulture and market gardening. The sandy soil originated from the Loukkos region called "R'mel", is inorganic and poor in nitrogen, its texture is sandy (Benicha et al, 2016;Elhani et al, 2019).…”

Humic Acid for Reducing Carbofuran Content of Rice Grown in Carbofuran-Contaminated Soil

“…The carbofuran adsorption capacity of the soils was low and dependent on organic carbon contents that plays a key role in the irreversibility of carbofuran adsorption (Shaheen et al, 2019). The availability of carbofuran in soil depends on the mineralization rate that increases with rise in temperature and moisture content (Benicha et al, 2013).…”