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Phytoaccumulation of Trace Elements by Wetland Plants: I. Duckweed
Author(s) -
Zayed Adel,
Gowthaman Suvarnalatha,
Terry Norman
Publication year - 1998
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1998.00472425002700030032x
Subject(s) - trace element , lemna minor , chlorosis , environmental chemistry , phytoremediation , wetland , chemistry , wastewater , aquatic plant , environmental science , botany , environmental engineering , heavy metals , biology , ecology , macrophyte , organic chemistry
There has been much interest recently in the use of constructed wetlands for the removal of toxic trace elements from wastewaters. Wetland plants play an important role in the trace elements removal process. It is not known, however, which wetland plant species absorb specific trace elements at the fastest rates. Such knowledge is essential to maximize the efficiency of trace element removal by wetlands. In this study, we investigated the potential of duckweed ( Lemna minor L.) to accumulate Cd, Cr, Cu, Ni, Pb, and Se when supplied individually in a nutrient solution at a series of concentrations ranged from 0.1 to 10 mg L −1 . The results show that under experimental conditions, duckweed proved to be a good accumulator of Cd, Se, and Cu, a moderate accumulator of Cr, and a poor accumulator of Ni and Pb. The highest concentrations of each trace element accumulated in duckweed tissues were 13.3 g Cd kg −1 , 4.27 g Se kg −1 , 3.36 g Cu kg −1 , 2.87 g Cr kg −1 , 1.79 g Ni kg −1 , and 0.63 g Pb kg −1 . Duckweed exhibited some symptoms of toxicity (e.g., reduced growth, chlorosis) at higher levels of element supply (except for Cr). The toxicity effect of each trace element on plant growth was, in descending order of damage, Cu > Se > Pb > Cd > Ni > Cr. We conclude that duckweed shows promise for the removal of Cd, Se, and Cu from contaminated wastewater since it accumulates high concentrations of these elements. Further, the growth rates and harvest potential make duckweed a good species for phytoremediation activities.