RESUMO
Several aquatic plant species have been proposed for phytoremediation of waters polluted with heavy metals and pesticides According to the limited information available, aquatic macrophytes also have a promising potential to remove NPs from aqueous media. Although there is considerable information on the remediation potential of Lemna spp., the capacity of Lemna trisulca seems to be neglected, particularly for nanoparticle removal. Therefore, in the current study, we aimed to investigate the removal efficiency of L. trisulca exposed to 3 different ZnO NP concentrations (2.5, 5, and 10 ppm) for 1, 4, and 7 days in Hoagland solutions and the removal percentage were measured on each duration and compared among groups. The accumulated zinc levels were measured in whole plant material and bioconcentration factors were calculated for each group. In addition, the effect of ZnO NPs on the photosynthetic activity of the plant was evaluated via analyzing the photosynthetic pigment (chlorophyll a and b) concentration. The removal percentage ranged between 9.3 and 72.9% and showed a gradual increase in all experimental groups based both on dose and test duration. The statistical comparisons of the removal percentage among the groups with or without the plant indicate that L. trisulca had a significant effect on removal rates particularly between 1st and 4th days of exposure, however, did not show any progress at 7th days. The only significant difference for chl-a and chl-b levels was observed in 10 ppm ZnO NP-exposed plants at 7th days.
