Lead recovery in artificially contaminated agricultural soil as a remediation strategy using sunflower and vermicompost

Abstract

Lead (Pb) contamination is an environmental problem that deteriorates the quality of agricultural soils; therefore, it is a priority to evaluate remediation strategies for its recovery. The aim of this research was to evaluate the effect of sunflower (Helianthus annuus) and vermicompost in the remediation of agricultural soils artificially contaminated with Pb. The treatments studied were: T1 (soil with Pb, vermicompost and sunflower), T2 (soil with Pb and vermicompost), T3 (soil with Pb and sunflower) and T4 (soil with Pb). The initial Pb value in the soil was 16.05 ppm, and 105 ppm Pb were added by dissolving Pb(NO3)2, reaching a concentration of 121.05 ppm as the initial level, higher than the national environmental quality standard (EQS) for agricultural soils (70 ppm Pb). All treatments reduced the Pb concentration in the soil below the EQS. T2 stood out by achieving a Pb recovery of 81.21 %. The Pb bioconcentration factor (BF) in the aerial part and roots of sunflower plants (T1 and T3) registered values of less than one, acting as an exclusive plant species. According to the Pb translocation factor (TF), sunflower in the presence of vermicompost (T1) behaved as a Pb phytostabilizing plant (TF < 1), and in the absence of vermicompost (T3) it proved to be a Pb phytoextractor (TF > 1).