Final answer:
Bioremediation of uranium uses metal-reducing bacteria to transform uranium into an insoluble state, thereby cleaning up uranium pollution. This process is similar to how certain bacteria convert toxic forms of mercury into nontoxic elemental mercury. Bioremediation also applies to the removal of a range of other pollutants, including agricultural chemicals and toxic metals.
Step-by-step explanation:
The question is regarding the bioremediation of uranium, which involves the use of metal-reducing bacteria to convert uranium into an insoluble form. This process helps to clean up uranium pollution by exploiting the natural abilities of certain microorganisms. An example closely related to the question is the microbial transformation of toxic mercury using bacteria such as Pseudomonas aeruginosa, which can convert Hg2+ into elemental mercury (Hg0), a nontoxic form. Similarly, in the context of uranium, bacteria alter the oxidation state of the metal to render it insoluble and thus reduce its mobility and toxicity in the environment.
Notable applications of bioremediation include the treatment of human sewage, cleanup of oil spills, and removal of agricultural chemicals from groundwater. Toxic metals like selenium, arsenic, and mercury can be removed through this process as well. For instance, the reduction of SeO42− to SeO32− and eventually to metallic selenium (Se0) is employed to remediate selenium ions from water. Bioremediation is enhanced by adding inorganic nutrients to support the growth of specific bacteria that metabolize the pollutants into less harmful substances.