Uranium

http://www.scientificamerican.com/article.cfm?id=the-science-of-the-silver&page=3 http://www.ted.com/talks/laura_robinson_the_secrets_i_find_on_the_mysterious_ocean_floor#t-666156

Plutonium plutonium http://www.oregonlive.com/pacific-northwest-news/index.ssf/2017/05/what_is_hanford_a_history_of_t.html