Use of Bacteria for Cleaning Radioactive Wastewaters


Use of Bacteria for Cleaning Radioactive Wastewaters

Raff, J.; Selenska-Pobell, S.

Saxony and Thuringia are mountainous German states featuring quaint villages, carved nutcrackers and centuries-old castles. But there is another side to this region. Decades of uranium mining to fuel former Soviet Union nuclear weapons and European nuclear power plants have devastated the region, which spills into the Czech Republic and Poland. Since the fall of the Berlin Wall, most mines have fallen into disuse, leaving an ominous legacy to threaten the long-term safety of the soil, subsoil and groundwater in nearby residential areas. Preliminary investigations in Thuringia and Saxony mining towns show elevated incidences of lung cancer in the men who worked the mines as well as in women who reside there.
These findings have raised fears about leaching and seepage of radionuclides from acid mine drainage waters and about contaminants from abandoned uranium waste rock piles dumped on valley slopes. Unfortunately, these environmental hazards are not limited to this region. Similar problems threaten the health of people in uranium mining areas in Hungary, Bulgaria, Estonia, Romania and Slovenia.
Closure, remediation and recultivation of former mining sites in Saxony and Thuringia have been underway since 1991. Conventional chemical and physical removal methods are useful for high concentrations of radionuclides and heavy metals, but not for low concentrations. After the initial remediation treatment, the remaining concentrations of these compounds are still above allowed limit values. So, scientists at Forschungszentrum Rossendorf Institute of Radiochemistry in Dresden, Germany are searching for alternative decontamination methods. They hope to develop a selective, yet effective process for completely removing metals and radionuclides from polluted effluents, wastewater, sediments and soils based on microorganisms.
Bacteria are the most frequent organisms on earth. They are able to live in extreme environments where higher organisms such as plants and animals are not able to survive, e.g. hot springs, antarctic ice, deep sea and deserts. For this reason it is not surprising, that researchers have found bacteria also in highly contaminated environments such as uranium mining waste piles. Above that the latter are big reservoirs for bacteria that are resistant to heavy metals. Many of the microorganisms living under these difficult conditions have developed different strategies to resist mobility and toxicity of metals and radionuclides. Bacteria interact not only with organic but also with inorganic compounds such as heavy metals. Some of them are able to solubilize metals or metalsulfides by oxidation. Others makes the opposite, they precipitate metals by reduction. Beside that many bacteria accumulate cobalt, molybdenum, lead, mercury, copper, manganese, aluminium, cadmium, gallium, barium and other toxic metals and transport them out of contaminated areas. All these properties offer interesting options for solving the above mentioned problems.

  • Genomics/Proteomics Technology 22(2004)2, 32L-32N

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Publ.-Id: 5877