Influence of humic acids in lowland peat on the remediation properties of wheat plants against heavy metal contamination

Abstract

Phytoremediation is a promising technology for removing heavy metals from soil and water. Despite the pronounced increase in heavy metal accumulation by cultivated plants under the influence of naturally occurring complexing agents, such as humic acids, their efficiency in phytoremediation has been poorly studied. In this regard, the aim of this work is to elucidate the effect of peat humic acid formulations on the remediation potential of wheat plants (Triticum aestivum L.) against heavy metal contamination. The influence of polymetallic pollution on the remediation properties of wheat was studied in model vegetation experiments using a culture solution. Plants were grown in a Hoagland nutrient solution. A complex exposure to heavy metals was simulated using 10 pmol/L CdSO4, 25 and 50 pmol/L CuSO4, 500 and 1000 pmol/L Pb(NO3)2 in various combinations with or without the addition of a peat humic acid formulation (0.005%).The phytoremediation efficiency of the humic acid formulation was determined by the removal of heavy metals during the heading stage of wheat growth. The research results showed that the phytoremediation efficiency of the humic acid formulation is defined by both an increase in the absorption of heavy metals and a decrease in their toxic action on the plants. In the case of mixed contamination of the solution with highly toxic heavy metals, the samples with humic acids showed a 1.2-2.5-fold increase in the accumulation of copper and cadmium by wheat plants. The data demonstrates the possibility of using the formulation of peat humic acids in phytoremediation technologies as an effector of heavy metal phytoextraction.