Light Assisted Phytoextraction of Landfill Leachate: An Effective Tool to Attenuate Pollutants in Landfill Leachate

In the presented experiment, we tested the influence of irrigation with different proportions of leachate collected from the leachate sump of municipal solid waste landfill in combination with LED light on the capacity of model plant to remove some heavy metals (HMs) (As, Cr, Cd, Ni and Hg) from the soil and to store them in the biomass of model plant Sinapis alba L. There were six variants irrigated either with distilled water (control) or with a combination of distilled water and leachate (20 %, 50 %, 75 %, 90 %, 100 %). The variants were divided into two groups: A (LED) and B (no LED) and concentrations of HMs and their interdependence (concentration of HM in the soil and in the plant) were monitored in the soil/plant samples. The measured values of HMs concentration in the soil and plant samples did not show a positive influence of LED light on the phytoextraction of HMs. A significantly increased (p ≤ 0.05) sorption of HM by the model plant was demonstrated only in Cd and Hg where the difference between Group A and Group B was approximately 10 mg kg–1. Furthermore, enrichment coefficient, EC, was established for the respective HMs and experimental variants. EC values > 1 indicating “high accumulator plants“ were measured for Cd and Hg for all variants of Group A. In Group B, EC values > 1 were recorded for Cd and Ni only in the control variants, and for Hg in all variants with the application of leachate (20 % → 100 %).