Soil amendments for cadmium phytostabilization by five marigold cultivars.

In recent years, ornamental plants have come under investigation as phytoremediation agents. In addition to reducing contaminant concentrations in soil, such plants support local economies by serving social (e.g., religious) and decorative purposes. Greenhouse studies investigated the phytostabilization potential of soil cadmium (Cd) by five cultivars of marigold (Tagetes erecta), a common ornamental flower in Asia. The effects of organic (cattle manure and pig manure) and inorganic (leonardite and Osmocote®) amendments in supporting plant growth and enhancing Cd uptake were also examined. Marigold cultivars Babuda and Sunshine grown in soil supplemented with pig manure produced the greatest biomass and experienced greatest Cd accumulation and flower production. In all treatments, plant parts accumulated Cd in the following order: root > shoot ≈ flower. Furthermore, Babuda and Sunshine cultivars had a high phytostabilization potential as evidenced by translocation factors < 1 and bioconcentration factors > 1 for roots. It is proposed that Babuda and Sunshine marigold cultivars be applied toward Cd phytostabilization while enhancing local economies as an ornamental species.