Abstract The aim of this study was to investigate the potential of duckweed (Lemna gibba) in
heavy metal (Pb and Cd) from water under different pH and metal loads. A total of three (2, 5
and 10 mg/L) strengths of Pb and Cd were used with varying pH (5, 7 and 9) and changes in metal
concentration and metal uptake yield of system were recorded. The Pb and Cd removal ranged
between 60.1% (2 mg/L at 9 pH) and 98.1% (10 mg/L at 7 pH) and 41.6% (10 mg/L at pH 9)
and 84.8% (2 mg/L at pH 7), respectively. The duckweed set-up with pH 7 showed the optimum
metal removal. The metal removal rate showed an inverse relationship with pH (r
2 > 0.60, for
all). Bioconcentration factor (BCF) and metal uptake yield per unit of dry biomass (qm) were
recorded: 403–738 and 445–616, respectively for BCFPb and BCFCd. The qm suggest the dose
(mg/L) 5 and 10 at pH 5 as the best combinations for the optimum removal. Results, thus suggest
that L. gibba can be a suitable candidate for removal of heavy metals from pollutant water bodies.
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