Influence of organic matter on the phytoremediation of sulfentrazone in contaminated soil

Abstract

Organic matter exerts an influence on the chemical, physical, and biological properties of soil. It can also influence the rates of herbicide degradation and sorption into it. This study aimed at evaluating the effect of adding organic compounds to soil over the remediation ability of the plant species Canavalia ensiformis (L.) (jack bean) in sulfentrazone-contaminated soil. The study was conducted in two phases. In the first phase, treatments consisted in a combination of four concentrations of organic compounds and in the application or not of sulfentrazone herbicide. After soil preparation, the herbicide was applied on the surface. Subsequently, seeds of the remediating plant species C. ensiformis were sown. At 75 days after emergence (DAE), samples of the aerial portions and roots of plants and soil were collected. All the collected material was frozen at approximately -20°C and then the accumulation of the herbicide on plants and soil was determined by chromatography. In the second phase, Pennisetum glaucum (L.) (pearl millet) was sown. This species is used as an indicator of sulfentrazone residue in the soil; biometric assessments were performed at 30 and 60 DAE. No sulfentrazone residue was found in the aerial portions or roots of the evaluated remediating plant species; however, it was detected in the soil. The increase in organic compound levels contributed to the growth and accumulation of biomass in pearl millet, when grown after the remediating plant species C. ensiformis, although it did not help phytoremediation.