Environmental Hazards are usually any chemicals that donot naturally occur to exist anywhere and are usually made in the fields of industry or experimental sciences
So if you happen for example to throw a bit of mercury in some river while being in a school trip then this is an environmental hazard created by humans
Sliding or rolling friction
One of the most worrisome waste products of a nuclear reactor is plutonium 239 (239Pu). This nucleus is radioactive and decays by splitting into a helium-4 nucleus and a uranium-235 nucleus (4He +... Q: One of the most worrisome waste products of a nuclear reactor is plutonium 239 (239Pu<span>).</span>
The symbol is U and its atomic number is 92