Lemna minor · Atlas of Contaminated Sites

How it works

Mechanisms: rhizofiltrationphytoextraction

Contaminants

Contaminant	Evidence	What was shown
Lead	greenhouse	Two raw effluents (municipal and mixed industrial) in hydroponics for 31 days: removal efficiency above 80% for Cd, Cu, Pb and Ni, with a maximum of 99% for nickel; highest bioconcentration factors of 558 for copper and 523 for lead, which the authors call those of a moderate accumulator (Bokhari et al. 2016). The reference study tested its accumulation of Cd, Cr, Cu, Ni, Pb and Se supplied singly at 0.1–10 mg/L (Zayed et al. 1998). Bokhari et al., Phytoremediation potential of Lemna minor L. for heavy metals, Int. J. Phytoremediation 18:25, 2016 Zayed et al., Phytoaccumulation of trace elements by wetland plants: I. Duckweed, J. Environ. Qual. 27:715, 1998
Arsenic	laboratory	In hydroponics, 22 days: removal of more than 70% of arsenic at an initial concentration of 0.5 mg/L, reached on day 15; the percentage falls as the initial concentration rises (Goswami et al. 2014). Goswami et al., Arsenic uptake by Lemna minor in hydroponic system, Int. J. Phytoremediation 16:1221, 2014
Copper	laboratory	Copper at 78 µM cuts biomass production by 60% and chlorophyll by 45% (Rofkar et al. 2014): accumulation has a toxicity ceiling. Rofkar et al., Uptake and toxicity of arsenic, copper, and silicon in Azolla caroliniana and Lemna minor, Int. J. Phytoremediation 16:155, 2014

Contaminant

Evidence

What was shown

greenhouse

Two raw effluents (municipal and mixed industrial) in hydroponics for 31 days: removal efficiency above 80% for Cd, Cu, Pb and Ni, with a maximum of 99% for nickel; highest bioconcentration factors of 558 for copper and 523 for lead, which the authors call those of a moderate accumulator (Bokhari et al. 2016). The reference study tested its accumulation of Cd, Cr, Cu, Ni, Pb and Se supplied singly at 0.1–10 mg/L (Zayed et al. 1998).

Arsenic

laboratory

In hydroponics, 22 days: removal of more than 70% of arsenic at an initial concentration of 0.5 mg/L, reached on day 15; the percentage falls as the initial concentration rises (Goswami et al. 2014).

Goswami et al., Arsenic uptake by Lemna minor in hydroponic system, Int. J. Phytoremediation 16:1221, 2014

Copper

laboratory

Copper at 78 µM cuts biomass production by 60% and chlorophyll by 45% (Rofkar et al. 2014): accumulation has a toxicity ceiling.

Rofkar et al., Uptake and toxicity of arsenic, copper, and silicon in Azolla caroliniana and Lemna minor, Int. J. Phytoremediation 16:155, 2014

Limits

It treats water at low concentrations, on the order of mg/L or less; at higher concentrations growth falls and removal with it. The trials cited are tank or laboratory tests, not operating plants. If the biomass is not harvested it dies and returns the metal to the water. Growth stops in winter.