Effect of Various Environmental Factors on Arsenic Accumulation in Dunaliella sp.

The accumulation of arsenic in Dunaliella sp. has been studied with respect to environmental factors such as pH, temperature, NaCl concentration and light intensity, in order to determine the optimal conditions for arsenic recovery. The accumulated amount of arsenic in Dunaliella sp. was measured as a function of time in a solution containing 10 mg As(V)l^-1 by DDTC-Ag/pyridine method at batch procedure. It was found that the amount of arsenic depended greatly on the environmental factors, and further varied considerably with time under given conditions, showing a maximum value at a certain time. The optimal conditions under which Dunaliella sp. accumulated arsenic most, was pH 9, 20°C, about 20 g NaCl.l^-1 and 4000 lux for the environmental factors described above, respectively. On the bases of the results obtained, it was suggested that the accumulation of arsenic in Dunaliella sp. was related to a metabolic activity caused by photosynthesis.