Potential of Helianthus annuus for phytoremediation of lead, zinc, total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) contaminated soil

摘要

This paper describes the results regarding effectiveness of treatment of soils contaminated with heavy metals (lead, zinc), total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs): naphthalene (Nap), phenanthrene (Phe), fluoranthene (Flt), chrysene(Chr), in the process of phytoremediation carried out a laboratory scale with the plant Helianthus annuus. The reason behind the work was to investigate how plant vegetation can reduce the concentration of heavy metals in the soil and how the presence of petroleum substances and polycyclic aromatic hydrocarbons affect the efficiency of their removal. The analysis was based on the dynamics of cleaning the contaminated soils which contained periodic testing on physical, chemical and toxicological properties of: uncontaminated soil, soil contaminated with TPH and PAHs, soil contaminated with heavy metals, soil contaminated with heavy metals and petroleum substances. Phytoremediation of soils and its effectiveness in pot experiments was assessed based on physical and chemical soil analyses as well as five microbiotests applying organisms belonging to three trophic levels: producers (Phytotoxkit™ and Spirodela Duckweed Toxkit), consumers (Ostracodtoxkit™) and decomposers (Microtox ®STP, MARA). The conducted research has shown that combining the results of chemical analyzes and biological tests on contaminated soils enable a real ecotoxicological assessment of environmental hazards. Six-month long phytoremediation of soils contaminated with heavy metals (Pb, Zn), and heavy metals together with petroleum substances (TPH, PAHs), yielded results in terms of a content reduction of: lead (from of 472-495 mg/kg dry mass of soil to 226-318 mg/kg d.m.), zinc (from 998-1030 mg/kg d.m. to 520-656 mg/kg d.m.), TPH (from 4806-4824 mg/kg d.m. to 2774-3180 mg/kg d.m.) and PAH (removal rates of Nap: at 28,0-29.9%, Phe: at 25.1-27.0%, Flt: at 24-26,3%, Chr: at 14.5-18.6%). After finishing the experiment the content of lead and zinc in the plant biomass was also measured. Based on the obtained results, conclusions were made regarding issues related to usage of phytoremediation to clean contaminated soils depending on the concentration and type of toxic substance.