Iranian Association of Environmental Health (IAEH)
Abstract
Aquatic macrophytes are known to accumulate various heavy metals in
their biomass. This accumulation is often accompanied by physiological
changes which can be used in biomonitoring for aquatic pollution. In
this study, the impact of copper (Cu) on the growth of the duckweed
Lemna minor, followed by its removal, was studied with 0.1–1.0
mg/L of Cu in a quarter Coïc and Lesaint solution at pH=6.1. In
order to verify duckweed tolerance to Cu, photosynthesis was measured
at the maximal concentration which caused no effect on the plant
growth. The results showed that copper inhibited Lemna growth at
concentrations ≥ 0.3 mg/L. At 0.2 mg/L, the final biomass was
approximately four times greater than the initial biomass. Analysis of
metal concentration in water showed that Lemna minor was responsible
for the removal of 26% of Cu from the solution. In the presence of Cu,
respiration was reduced, while photosynthesis increased considerably.
Net photosynthesis approximately increased three times compared to the
control. Copper was responsible for 130-290% increase in the
photosynthetic activities. These results suggested that Lemna minor
could be a good tool for the evaluation of copper pollution in
biomonitoring programs
