ACCUMULATION AND RETENTION OF LEAD BY CATTAIL (TYPHA DOMINGENSIS), HYDRILLA (HYDRILLA VERTICILLATA), AND DUCKWEED (LEMNA OBSCURA)

ABSTRACT

Investigation of lead levels in Delaney Creek, which flows through a former lead-acid battery manufacturing and disposal site in Tampa, FL, revealed low but significant lead levels in the water and sediments along the creek,[1] Known phytoaccumulator plants populate certain locations within the creek and adjacent wetlands. Three representative plants from the study site—cattail (Typha domingensis Pers.), hydrilla (Hydrilla verticillata Royle), and duckweed (Lemna obscura L.)—were investigated for their potential to remove lead from contaminated waters under the controlled conditions of a phytotron room. The plants were collected at the site and cultured in hydroponic medium under conditions that mimicked their natural environment (26°C and 80% humidity). Results indicate that, of the three species, duckweed and hydrilla achieve high lead removal efficiencies after a short exposure period (98% removal using hydrilla, 97% with duckweed after one week of exposure) while cattail appears to be less efficient than the other two species. The kinetic rates of lead removal were studied for Lemna obscura.

Keywords:

• Lead contamination
• Phytoremediation
• Phytoaccumulation
• Metal uptake

ACKNOWLEDGMENTS

We thank Dr. Richard Wunderlin, USF Herbarium, who identified the collected species. Also we are thankful to Kenneth Gordon and Erin Mikkola for technical assistance.