Screening of aquatic plants and algae for removal of toxic heavy metals

Aquatic plants and algae are known to accumulate metals and other toxic elements fromsolution. Different plant and algae species, even strains of the same species, exhibit largevariability in their capacity to sequester toxic elements. Bioremoval of toxic elements is alsogreatly affected by the presence of other ions and the physical-chemical factors during contacting.Therefore a plant/algae screening program, using simulated and actual contaminated water is therequired first step in development of a bioremoval process. This paper summarizes results from ascreening process used to determine the capability of sea weeds, aquatic plants and algae foradsorbing the heavy metals Cd, Zn, Pb, Ni and Cu. A successful candidate would exhibit thefollowing characteristics: 1) Capability to reduce metal concentrations to the required regulatorylevels; 2) High specific metal adsorption capability (mg metal adsorbed/kg of dry biomass); 3)Capability of removing several metal ions simultaneously; 4) High productivity in a low costcultivation system; 5) Ease of harvesting, processing, storage and/or separating biomass fromcultivation water; 6) Ability to be regenerate and recover metals.