Soils contaminated with heavy metals including cadmium, lead, zinc, copper, and chromium continue to represent a significant environmental issue, particularly in areas affected by industrial activities. In this context, the present study aimed to assess the feasibility and efficiency of an integrated bioremediation technique that combines, in a synergistic approach, phytoremediation with the use of natural amendments in order to reduce soil pollution with heavy metals. In addition, the potential for heavy metal recovery was investigated. The experiments were conducted under field conditions in the vicinity of the CET II Holboca power plant, using two plant species, Trifolium repens and Brassica napus, as bioaccumulators, while biochar was applied as a natural amendment. The analyses focused on metal concentrations, translocation factors, the degree of heavy metal recovery, and morpho-structural characteristics. The results indicated a high accumulation of metals in plant roots, particularly in soils treated with higher doses of biochar (4905.93 mg/kg iron for B. napus), and a significant growth stimulation (root elongation increases of up to 78% in T. repens and up to 29% in B. napus). B. napus exhibited greater translocation of metals to the aerial parts (with values up to 0.83 for zinc), whereas T. repens predominantly retained metals within the root system. The highest recovery efficiency values were observed in the case of lead, reaching 224.7% in T. repens and 86.7% in B. napus in soil amended with increased amounts of biochar. Overall, biochar application stimulated plant growth and enhanced metal uptake efficiency, suggesting a viable and practically applicable method for the ecological reconversion of contaminated land.
Zotica et al. (Mon,) studied this question.