Persistence and degradation of carbofuran in Spanish soil suspensions

The objetive of this work was to assess the processes involved in the fate of carbofuran in water suspensions of five soils of Southern Spain. The evolution of carbofuran was monitored in the solution phase by HPLC from 15 minutes to 12 days of interaction at 30 and 40°C and with non-sterilized and with sterilized soil samples. The kinetic profile of carbofuran disappearance in the presence of soil suspensions is consistent with three consecutive steps assumed as sorption and fast and slow degradation. The two degradation steps fit the first order reaction equation from which rate constants were evaluated. The main process determining the disappearance of carbofuran from the suspensions is the abiotic degradation by hydrolisis at the carbamate linkage producing carbofuran phenol as degradation product. Short half-lifes of 1–2 days obtained suggest low contamination potential of carbofuran for waters.