Phytoremediation potential of Dilang-aso (Pseudelephantopus spicatus (Juss.) Rohr) in lead-contaminated soil

Abstract

This study investigated Pseudelephantopus spicatus, a member of the family Asteraceae that has not yet been explored in terms of its phytoremediation potential. This study utilized two pot experiments: (1) plant tolerance to lead (Pb)-contaminated soil, and (2) plant mechanism for Pb uptake. For the plant tolerance experiment, plants were exposed to different lead concentrations, and the shoot length, width of the largest leaf, and number of leaves were recorded. For the Pb uptake experiment, P. spicatus plants were transplanted in polyethylene bags containing 1 kg of 500 ppm Pb-treated soil, and were observed every five days for 30 days. Results showed that P. spicatus plants in Pb-treated soil had significantly shorter shoot length, smaller width of largest leaf, and reduced number of leaves, as compared to the control treatment. The Pb uptake of P. spicatus also increased with longer exposure time. However higher Pb concentration was still observed in the soil (218.57 ppm) compared to the Pb concentration in roots (29.49 ppm) and shoot (17.07 ppm). Thus, the P. spicatus plant demonstrated tolerance as a Pb excluder, and may not be a good candidate for phytoremediation. However, other studies may investigate whether the phytoremediation potential of P. spicatus can be improved by observing the effects of different Pb concentrations, higher time intervals response, or the use of chelating agents and fertilizers.