Absorption and translocation of copper and arsenic in an aquatic macrophyte Myriophyllum alterniflorum DC. in oligotrophic and eutrophic conditions

The aim of this study is to evaluate copper and arsenic accumulation and translocation at a concentration of 100 mu g/L of a submersed macrophyte Myriophyllum alterniflorum. The trophic level (eutrophic and oligotrophic conditions) of the medium was also considered. To achieve this goal, plants were incubated for 21 days in the presence of 100 mu g/L of Cu or AsV. The heavy metal transfers from the contaminated medium to plants and into plant tissues was discussed in terms of the bioconcentration factor (BCF) and the translocation factor (TF). Malondialdehyde (MDA) content in tissues was analyzed in order to study the toxicity of these two contaminants. Our results show that copper was more accumulated in shoots, than roots, whereas the opposite trend was observed for arsenic. In addition, the two contaminants were more accumulated in oligotrophic than eutrophic medium. The BCF of copper in shoots was 1356 in oligotrophic condition, while that of arsenic was higher in roots about 620 in the same condition. The TF was less than 1 for arsenic, and higher than 1 for copper, indicating that watermilfoil restrains the translocation of arsenic to shoots, while it has a low capacity to control the translocation of an essential micronutrient like copper. An increase in MDA content was observed under Cu and As stress. On the basis of this experiment, M. alterniflorum has a higher accumulation potential of copper and arsenic, and therefore, it can be a good candidate for the phytofiltration of these two contaminants from water.