| has gloss | eng: Part of the actinides in the environment series. Plutonium in the environment since the mid-20th century has primarily been due to human activity. The majority of plutonium isotopes are short-lived on a geological timescale. It has been argued that some natural plutonium (the very long lived 244Pu isotope) can be found in nature. This isotope has been found in lunar soil, meteorites, and in the Oklo natural reactor. But in general it is normally considered that the bulk of all plutonium is man made. According to one paper on marine sediments for plutonium in marine sediments, bomb fall out is responsible for the majority of the 239Pu and 240Pu (66% and 59% respectively of that found in the English Channel) while nuclear reprocessing is responsible for the majority of the 238Pu and 241Pu present in the sea (bomb tests are only responsible for 6.5 and 16.5% of these isotopes respectively). |
