Abstract: This research has been accomplished in two separated phases. The aim of the first phase was to evaluate arsenic concentration in the surface water and plants in Chelpo area in different seasons. In addition, pH and DO in water samples were measured. The aim of this study at second phase was to investigate the efficiency of arsenic removal from surface water using macro-alga; Chara vulgaris. Four reactors were used in this study with the initial arsenic concentrations of 50, 100, 200 and 300 μg L–1. Arsenic concentration in water and algae, pH of the media, initial and final weight of Chara vulgaris were measured during the experiment. High concentrations of arsenic were found in surface water of Chelpo area. The maximum contamination of arsenic (150 μg L–1) was observed in winter. It was found that the arsenic concentration in algae was high due to high affinity of the algae for arsenic uptake. The results of the second phase showed that Chara vulgaris could significantly remove arsenic from polluted water. The arsenic content of alga increased approximately to about 62.7 mg kg–1 dry weight in 19 days of exposure in the reactor with initial concentration of 300 μg L–1. The high arsenic accumulation ability of Chara vulgaris could reduce arsenic by averagely 66.25% in the contaminated water of the reactors.