Role of the spontaneously occurring vegetation on remediation of potential metal polluted soil: a case study in the landfill site of Ziama Mansouriah, north-eastern Algeria

Abstract

The aim of this study was to assess the accumulation of heavy metals in spontaneously occurring vegetation and soil at the Ziama Mansouriah landfill site in Algeria. The plants selected for analysis were Mentha spicata, Silybum marianum, Dittrichia viscosa, and Pteridium aquilinum. Soil samples were collected randomly from the surface at a depth of 0–40 cm and analyzed for physicochemical parameters. The heavy metal concentrations (Cd and Zn) in soils and aboveground phytomass were measured using flame atomic absorption spectrometry. The physicochemical analysis showed that the pH ranged from 7.65 to 7.87, electrical conductivity (EC) ranged from 37.10 to 49.10 mS.cm⁻¹, organic matter (OM) ranged from 3.89 to 4.45%, and cation exchange capacity (CEC) ranged from 324.10 to 341.20 cmol⁺.kg⁻¹. The soils were found to have a clay texture. The concentrations of Cd and Zn in the soil ranged from 2.70 to 3.54 and 289.3 to 306.6 µg.g⁻¹, respectively, which were all above the permissible limits. The contamination/pollution index showed that soil quality varied between severely contaminated and slightly polluted status. Significant differences were observed in the average concentrations of the two metals in plants (p < 0.05). The results indicated that Mentha spicata was the most effective in taking up metals and had a higher transfer coefficient (TC) of Cd and Zn, indicating its higher accumulation ability compared to the other species.