Mobilization and Translocation of Subsurface Lead by Tithonia rotundifolia

Phytoremediation is a cost-effective and relatively cleaner method for remediating contaminated areas using plants. Certain plants, including some sunflower species, have already been identified as potential phytoremediation candidates because of their ability to accumulate heavy metals. This study investigated the ability of Tithonia rotundifolia (red sunflower) to accumulate lead from lab-contaminated soils. T. rotundifolia was assessed as a candidate for phytoremediation of lead soils. The study also assessed whether the form (species) of lead as the source of contamination or whether arbuscular mycorrhizal fungi had effects on plant uptake of the metal. Results showed that T. rotundifolia was able to accumulate up to 33% of the lead from the contaminated soils making it a promising candidate for phytoremediation. The amount of lead taken up by the plant ranged from 0.1 to 1.2 mg/kg of plant biomass. The source of the contamination, either lead nitrate or lead carbonate, had a significant impact on the amount of lead that accumulated in the plant. The sunflowers grown in the lead nitrate treatment were able to accumulate significantly more lead than the sunflowers grown in the lead carbonate treatment.