Phytoremediation of copper, iron and mercury from aqueous solution by water lettuce (Pistia stratiotes L.)

Abstract

This study investigated the potential of water lettuce (Pistia stratiotes L.) for removal of copper, iron and mercury (Cu2+, Fe3+ and Hg2+) from their aqueous solution amended at different concentration (5, 10 and 15 mg L−1). The different plant growth attributes viz., fresh plant biomass, total chlorophyll content, kinetic plant growth rate and plant root size were estimated. The results showed that the highest removal of selected metals (Cu2+: 53.20%, Fe3+: 83.20% and Hg2+: 62.14%) was observed in 5 mg L−1 treatment. The fresh plant biomass (Cu2+: 45.57; Fe3+ 90.82 and Hg2+ 47.27 g), chlorophyll content (Cu2+: 2.99 ± 0.03; Fe3+ 4.26 ± 0.06 and Hg2+ 3.02 ± 0.03 mg g−1 fwt), kinetic growth rate (Cu2+: 0.0004; Fe3+ 0.0011 and Hg2+ 0.0006 gg−1day−1) and plant root size (Cu2+: 12.28; Fe3+ 16.54 and Hg2+ 12.86 cm) were maximum in 5 mg L−1 treatment. The translocation factor of Cu2+, Fe3+ and Hg2+) was also 0.05) in the plant tissues. This study suggested that the most efficient remediation of Cu2+, Fe3+ and Hg2+ and the maximum growth of P. stratiotes can be achieved at 5 mg L−1.