Some of this natural plutonium is related to uranium. Some has been found in meteorite dust deposited in the seabed. So, plutonium-244 is the heaviest naturally occurring element that we know of.

Instead, the tremendous heat generated by the natural decay of plutonium-238—up to 475º F in the New Horizons probe—is converted to electricity in a radioisotopic thermal generator (RTG).

Given plutonium’s long half-life, we humans have permanently altered what once was our natural environment. We no longer live in an environment of purely natural background radiation.

Plutonium-238 is 280 times more radioactive than Plutonium-239, the plutonium isotope used in atomic bombs and as a “trigger” in hydrogen bombs. There are 10.6 pounds of Plutonium-238 on ...

Furthermore, between 1953 and 1986, the government pumped an annual average of 360 million gallons of contaminated waste – including plutonium – directly into the groundwater.

Highly toxic plutonium has seeped into the soil outside the troubled Fukushima Dai-ichi nuclear power complex in northeastern Japan, officials say. The amounts detected in two different soil ...

For the first time in 35 years, the US National Nuclear Security Administration (NNSA) has manufactured a plutonium pit for use in a nuclear weapon. Functioning as a radioactive core for nuclear ...