The metal bioaccumulation potential of selected macroalgae species as different pH ranges
were study for usage as part of a possible secondary passive AMD treatment technology in
algae ponds in temperate regions during winter months. . Two separate studies were
conducted to determine the suitability of macroalgae for passive treatment when metabolic
processes in macrophytes and microrganisms in constructed wetlands decreases due to
seasonal changes. In the field study, the bioconcentration of metals (mg/kg dry weight) measured in the macroalgae mats were in the following order: site 1. Oedegonium crassum
Al > Fe > Mn > Zn; site 2. Klebsormidium klebsii, Al > Fe > Mn > Zn; site 3. Microspora
tumidula, Fe > Al > Mn > Zn and site 4. M. tumidula, Fe > Mn > Al > Z. In the laboratory
study, cultured macroalgae K. klebsii, O. crassum and M. tumidula isolated from the field
sampling sites were exposed to three different pH values (3, 5 and 7), while bioaccumulation
of the metals, Al, Fe, Mn and Zn and glutathione-S-transferase (GST) activity was measured
in the different algae species at a constant water temperature of 14 ˚C. . Bioaccumulation of
Al was the highest for O. crassum followed by K. klebsii and M. tumidula (p < 0.0001). From
the study it was evident that the highest metal bioaccumulation occurred in the macroalgae O.
crassum at all three tested pH values under constant low water temperature.