Experience of a two-year phytoremediation field trial in the “Phy2Climate” project: Lithuanian case

Phytoremediation is considered as an environmentally friendly and cost-effective technology for the treatment of contaminated soil. Recently, there has been an increase in large-scale phytoremediation projects, one of the key moments of which is the transition from a pot experiment to large-scale field research under real conditions. The “Phy2Climate” project aims to provide clean biofuel production and phytoremediation solutions from contaminated lands worldwide, and field trials under real conditions was a focal point in this project. The trials were established in countries like Serbia, Spain, Argentina, and Lithuania, to cover different climatic conditions and differently polluted areas.

In Lithuania, the field trials were established in a site that was formerly used as oil base in Soviet times and up-until-today exhibits contamination with petroleum hydrocarbons. Main method for phytoremediation of petroleum-contaminated soil is the rhizodegradation, which focuses on stimulating the population of organic-degrading microorganisms through the plant rhizosphere. Thus, contaminated soil in the site was amended with organic and mineral fertilizers to promote plant development and increase biomass outputs. Furthermore, microbial  additive applied to ensure rhizodegradation. Two monocultures (amaranth (Amaranthus caudatus) and Jerusalem artichoke (Helianthus tuberosus) and a mix of herbaceous plant species were grown on different subplots in the prepared soil for two consecutive years. The key parameters used to assess the efficiency of phytoremediation included biomass output, crucial for ensuring an adequate amount for biofuel production, and the phytoremediation factor, indicating changes in petroleum hydrocarbon concentration in the soil.