Uranium--From where does it originate & does it changes the enviroment ?

Where does uranium originated?

Uranium is a naturally-occurring element generally found at the low levels in almost all rock, soil, and water. Major concentrations of uranium occur in some substances such as phosphate rock deposits and minerals such as uraninite in uranium-rich ores since, uranium has such a long radioactive half-life (4.47x109 years for U-238), and the total amount of uranium stays on earth.

Does uranium changes the environment?

In general all uranium isotopes are radioactive. The three natural uranium isotopes found in the environment are U-234, U-235, and U-238; which undergoes radioactive decay by the emission of an alpha particle accompanied by weak gamma radiation.

The dominant isotope, U-238, forms a long series of decay products which includes the key radio nuclides radium-226, and radon-222. This decay process continues until a stable, non-radioactive decay product is formed uranium decay series so, they release the radiation during the decay process which raises the health concerns.