The increasing contamination of soil, sediment, and water with heavy metals by natural and industrial processes is a worldwide problem. Biosorption and bioaccumulation of heavy metals are the most promising technology involved in the removal of toxic metals from industrial waste streams and natural waters. Metal removal treatment systems using microorganisms are cheap because of the low cost of sorbent materials used and as they do not add other ions or toxic chemicals to the environment. Many bacteria and microalgae have demonstrated ability to absorb toxic elements. The present review discusses processes of: (a) chromium accumulation by Arthtobacter genera, (b) mercury accumulation by bacteria Arthrobacter globiformis and biosorption by microalgae Spirulina platensis; (c) zinc biosorption from model systems and waste water by Spirulina platensis. Most powerful primary analytical technique, neutron activation analysis, was applied to study elemental composition of microorganisms.