Arsenic is one of the most important toxicants in surface and ground water. Several researchers have studied the use of phytoremediation process for the removal of different pollutants in soil and water. The aim of this study was to investigate the arsenic removal from surface water of Chelpo area in north-east of Iran using the macro-algae, Chara. Four reactors were used in this study with the initial arsenic concentrations of 50, 100, 200, and 300 mgr/L. Besides the assessment of arsenic concentration in water and algae, the pH of the media, and the initial and final weights of Chara were measured. The results showed that Chara could significantly remove arsenic from the polluted water. The maximum arsenic removal was observed in the reactor with initial concentration of 50 mgr/L. The highest arsenic concentration in macro-algae at the end (day 19) reached 62.7 mg/kg dry Chara in the reactor with initial arsenic concentration of 300 mgr/L.

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