A rapid bioassay for the determination of carbendazim residues in soil

A simple and rapid bioassay for the direct determination of carbendazim residues in soil was developed. Pellets composed of mixtures of soil (200–500 mg) and agar were placed on an agar medium pre–inoculated with the test organism Penicillium digitatum. After cold pre–incubation followed by incubation at 27°C, the size of the inhibition zone was determined. The lowest detectable concentrations of carbendazim and thiabendazole in a sandy soil were 0.25 and 10 μg/g, respectively. The lowest detectable concentration was higher in heavy soils. In a study of carbendazim degradation in soil, chemical analysis and the pellet bioassay technique yielded similar results. This technique requires only small quantities of soil, without the need for soil extraction.