Accumulation of arsenic and selenium by Dunaliella sp.

The unicellular marine alga, Dunaliella sp., was grown in seawater containing selenium and arsenic. Dunaliella sp. readily took up selenite from the medium over a broad range of concentrations (10⁻¹⁰–10⁻⁵mol dm⁻³). In comparison, uptake from selenate was generally minimal. Selenite was detectable in cells within 24 h and concentrations increased gradually with time. Also iron and zinc concentrations in Dunaliella sp. cells were largely affected by addition of arsenic and gallium. Arsenic concentrations in cultures were largely correlated to the accumulation of arsenic by Dunaliella sp., but did not affect the accumulation of selenium by Dunaliella sp. This implied that the accumulation process of selenium was different from that of arsenic.