Absorption and Adsorption of Heavy Metals by Microalgae

Heavy metals are released into waterways due to various anthropogenic activities. Their treatment is of special importance, since heavy metals are nonbiodegradable and persist in the environment posing a threat to the biota due to their toxic nature. In this chapter, the current methods that have been used to remove and/or detoxify heavy metals in aquatic environments are reviewed with specific emphasis on microalgae. A literature survey indicates microalgae have developed a wide spectrum of absorption (extracellular) and adsorption (intracellular) mechanisms for coping with heavy metal toxicity. The potential of prokaryotic and eukaryotic microalgae living cells or their dead cell biomass in comparison to currently available physicochemical processes aimed at removing toxic heavy metals is discussed. Also addressed are the mandatory requirements to bring this heavy metal removal potential to an applicable, commercial stage.