Risk of Soil Recontamination Due to Using Eleusine coracana and Panicum maximum Straw After Phytoremediation of Picloram

• Published in: International journal of phytoremediation 2015-04, Vol.17 (4), p.313-321
• Main Authors: Nascimento, Alex Favaro, Pires, Fábio Ribeiro, Chagas, Kristhiano, Procópio, Sergio de Oliveira, Oliveira, Marcelo Antonio, Cargnelutti Filho, Alberto, Belo, Alessandra Ferreira, Egreja Filho, Fernando Barboza
• Format: Article
• Language: English
• Subjects: African finger millet; bioassays; Biodegradation, Environmental; Biomass; Bioremediation; carryover; clay; crop-livestock integration system; Eleusine - chemistry; Eleusine - metabolism; Eleusine coracana; Environmental Restoration and Remediation - instrumentation; Environmental Restoration and Remediation - methods; Extraction processes; Glycine max; growth chambers; herbicidal properties; Herbicides; Herbicides - analysis; Herbicides - metabolism; high performance liquid chromatography; Indicator organisms; leaves; maceration; Metabolites; Panicum - chemistry; Panicum - metabolism; Panicum maximum; Phytoremediation; phytotoxicity; picloram; Picloram - analysis; Picloram - metabolism; Plant Stems - chemistry; Plant Stems - metabolism; Plants (organisms); polluted soils; Remediation; risk; Sand; shoots; Soil (material); Soil contamination; Soil Pollutants - analysis; Soil Pollutants - metabolism; Soybeans; stems; Straw; Tanzania; Texture; tillage
• ISSN: 1549-7879; 1522-6514; 1549-7879
• DOI: 10.1080/15226514.2014.909775

This study aimed to evaluate the herbicidal activity of picloram on the biomass of the remediation plants Eleusine coracana and Panicum maximum after cultivation in a soil contaminated with this herbicide. These species were grown in three soils, differentiated based on texture (clayish, middle, and sandy, with 460, 250, and 40 g kg –¹ of the clay, respectively), previously contaminated with picloram (0, 80, and 160 g ha –¹). After 90 days, the plants were harvested and an extract was produced by maceration of leaves and stems of these plants. It was applied to pots containing washed sand, comprising a bioassay in a growth chamber using soybean as a bioindicator for picloram. Soil and plant samples were analyzed by HPLC. The results showed the presence of picloram or metabolites with herbicidal activity in the shoots of E. coracana and P. maximum at phytotoxic levels with regard to soybean plants, indicating that they work only as phytoextractors and that the presence of straw on the soil surface can promote recontamination within the area. It is not recommended to cultivate species susceptible to picloram in areas where it was reported remediation by E. indica and P. maximum and still present residues of these species.