Environmental Chemistry and Ecotoxicology (Jan 2021)
Application of Aztec Marigold (Tagetes erecta L.) for phytoremediation of heavy metal polluted lateritic soil
Abstract
Heavy metals are pollutants of great concern due to their toxicity and immutable nature. As a result of human actions such as mining, industrial activity and agricultural practices, heavy metals find their way in to the soil. Phytoremediation is a a cost-effective, non-intrusive, and aesthetically pleasing technology in which herbaceous plants and trees are used to remediate and remove pollutants from soils. In the present study, potential of Tagetes erecta L. was assessed for phytoremediation of cadmium (Cd), lead (Pb) and zinc (Zn) contaminated lateritic soil. Pot experiments were conducted for various concentrations of heavy metals (ranging from 20 mg/kg to 160 mg/kg). The plant uptake of the heavy metals was analyzed after a 12-week growing period and was determined by analyzing residual heavy metal concentrations in aerial and subterranean parts of the plant by atomic absorption spectrophotometry (AAS). The total uptake of heavy metals by the plant increased with increasing heavy metal concentration in the soil. Considering the plant as a whole, the ability to uptake Zn and Cd was comparable and was significantly higher, approximately 13 times on average than its ability to uptake Pb. At lower concentrations, the ability was slightly higher for Cd, but at higher concentrations, Zn uptake was slightly higher. The order of accumulation of heavy metals in Tagetes erecta L. shoots was in the order of Cd > Zn > Pb, and the same order for roots was Zn > Cd > Pb. The bioconcentration factor (BCF) was greater than 1 for Cd (soil concentration < 160 mg/kg) and Zn (all spike concentrations) and less than 1 for Pb. The translocation factor (TF) was greater than 1 for Cd (soil concentration < 160 mg/kg). Tagetes erecta L. was found to be an effective phytoextractor for Zn and Cd and an excluder for Pb.
