Subsurface Bacteria: Nature’s Solution To Uranium Pollution

by | Jul 1, 2023 | Ecology, Environment, Pollution, Water Pollution

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Uranium pollution refers to the contamination of the environment, including soil, water, and air, with uranium or its radioactive isotopes. Uranium is a naturally occurring radioactive element that can be found in various geological formations and mineral deposits. It is primarily used in nuclear power plants, weapons production, and some industrial processes. In this blog, we are going to focus on the underground water pollution caused by uranium specifically.

Uranium is a radioactive element found naturally in bedrock that is toxic to humans and ecosystems. Drinking water getting exposed to Uranium, such as through wells drilled in bedrock, may cause renal and reproductive consequences, along with DNA damage. Drinking water contaminated with uranium is a big global health concern. The subsurface bacteria create chemicals that aid in transforming uranium, allowing it to be more easily integrated into minerals. This sink stabilizes the uranium and prevents it from being transported further by groundwater.

Bio-Stimulation Role In Resolving Uranium Groundwater Pollution

At the time of the Cold War, many sites where uranium was mined and processed for nuclear weapons were polluted with uranium, which proved to be an issue for groundwater pollution. Oxidized uranium is highly toxic to the environment and can be found in groundwater. This increases the polluted area since dissolvable uranium is portable in this circumstance. The professionals have explored and devised solutions to the problem of groundwater pollution.

Using biostimulation is one way they consider the most valuable and powerful. This strategy arranges for the metal-reducing microorganisms of the polluted area to take the oxidized uranium and convert it to a non-soluble precipitate. The contaminated areas’ native bacterial flora can be used to solve the uranium pollution problem. Bio-stimulation with acetate was so effective that feeding them with the electrons they needed to increase the quantity of metal-reducing subsurface bacteria.

How Do The Subsurface Bacteria Help Absorb Uranium And Clean The Groundwater?

Bioremediation is a method that uses microorganisms to detoxify, reduce, or remove environmental toxins. Microorganisms can be directly introduced into a polluted region, and nutrients can stimulate growth. Carbon introduced into the ground can sometimes effectively promote the development of microorganisms that can lower U (VI). In general, uranium bioremediation is based on the minor reduction of dissolvable U (VI) to dissolvable U (IV) or on the biosorption of U (VI), indeed, biomass. This procedure extends the half-life of metals, helps repair uranium, and prevents it from polluting groundwater.

Biosorption of U (VI) and the growth of many subsurface bacterial communities are difficult to initiate in settings generally deficient in nutrients with various chemical and physical qualities. When the uranium is fixed, it is also critical to prevent reoxidation or desorption. As a result, a proper bioremediation approach will always rely on a thorough understanding of the area’s microbiological, geochemical, and geological aspects to be decontaminated.

The Power Of Subsurface Bacteria In Transforming Uranium Into Stable Rock Formations

Microbes help to transform uranium into rock deep within the bedrock in an oxygen-free environment. Uranium is a naturally occurring radioactive element that is dangerous to humans and ecosystems. Drinking water exposure, such as via drilled wells in bedrock, can result in renal and reproductive consequences and DNA damage. The experts spent 17 years exploring deep boreholes bored into the bedrock, identifying materials containing substantial amounts of uranium. It was discovered that subsurface bacteria living in an oxygen-free environment were crucial to the process. The bacteria create chemicals that aid in transforming uranium, allowing it to be more easily integrated into minerals. This sink stabilizes the uranium and prevents it from being transported further by groundwater.

The data imply that naturally occurring microorganisms have an impact on uranium removal. Microbes help to build hazardous element sinks within the subsurface environment. This approach can significantly reduce the spread of dangerous substances throughout the territory. Uranium is the primary component of spent nuclear fuel, which will eventually be placed in deep bedrock systems for long-term geological storage.


Subsurface Bacteria: Nature's Solution to Uranium Pollution

Subsurface Bacteria: Nature’s Solution to Uranium Pollution

How Subsurface Bacteria Safeguard Groundwater By Neutralizing Uranium

Following are some studies conducted by the researchers that show the importance of subsurface bacteria as a tool against harmful uranium:

Geobacter species

Geobacter species are primarily known for their metal reduction abilities and potential to responsibly speed the bioremediation of radioactive oxidation in organic subsurface habitats. They can undertake anaerobic oxidation of organics and are therefore severe for groundwater bioremediation by lowering the contamination of metals such as Fe (III) and other contaminants such as uranium. Geobacter species may also directly transfer electrons to an electrode, making them suitable for microbial fuel cells. Geobacter species are recognized for the bioremediation of radioactive and poisonous metals in polluted sublevel habitats and for converting organic mixtures to electricity in microbial fuel cells. They are among the most effective microorganisms. Geobacter species capable of transferring their new electrons can transfer electrons outside the cell and transport them over longer distances via conductive lines, referred to as microbial nanowires, and are, therefore, of interest.

Geobacter species play an essential role in environmental regeneration and are of interest. For example, Geobacter species can remove radioactive metal pollutants from groundwater by oxidizing mixtures of petroleum contaminants in polluted groundwater to inoffensive carbon dioxide.

A bacterial strain that “breathes” uranium

A bacterial strain that “breathes” uranium could hold the secret to cleaning up polluted groundwater near sites where uranium ore was processed to produce nuclear bombs. It is the first time scientists have discovered a bacterium from the beta proteobacteria class that breathes uranium. This bacterium can breathe either oxygen or uranium to fuel the chemical reactions that give it life. Uranium becomes immobile once the newly discovered bacteria interact with uranium molecules in water. Because it is no longer dissolved in groundwater, it cannot contaminate drinking water brought to the surface.

Breathing uranium is scarce in the microbiological world. Most subsurface bacteria capable of respiring uranium cannot inhale oxygen and must rely on metal compounds, often made from solid iron. Scientists had previously seen reduced uranium concentrations in groundwater when iron-breathing bacteria were active. However, they had yet to demonstrate that the iron-breathing bacteria directly respired the uranium. While the bacteria’s chemical interaction with uranium is a typical process known as “reduction,” or the act of absorbing electrons, it is yet unknown precisely how the decreased uranium generated by this bacterium would behave in the underground environment. They appear to create uranium nanoparticles. However, the mineralogy remains unknown and will be the topic of future research.


Uranium pollution by contamination of soil and groundwater is a severe threat to human health. Stimulating microbial communities to fix these radionuclides has proven to be an effective way for uranium cleanup, albeit an unacceptable method. The microbial reduction of U (VI) is complicated because uranium cannot be destroyed. Following the remediation operations, U (VI) may attach to sediments, preventing reduction and causing consistency in a polluted area. Furthermore, biotic and abiotic activities oxidize the fixed U (IV), reversing the remediation process. Researchers who have studied this technology have proposed that bioremediation might be implemented on the market immediately. However, more recent research must be incorporated into the uranium bioremediation technology to improve this process’s competency and liability.

Also Read: Can life on Earth co-exist with Radiation?


  • Dr. Tanushree Kain

    Tanushree is a passionate Environmentalist with a Doctorate in Environmental Sciences. She is also a Gold medalist in Master of Science (M.Sc), Environmental Sciences. She has 6 years of experience as a guest faculty in Environmental Sciences. With her combination of technical knowledge and research expertise, she can create clear, accurate, and engaging content that helps users get the maximum information regarding environmental topics.


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