Accumulation and retention of lead by cattail (Typha domingensis), hydrilla (Hydrilla verticillata), and duckweed (Lemna obscura)

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 (26degreesC 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.