> Which of the 14 isotopes are you referring too? In general, synthetic isotopes unknown in our evolutionary biology are far more toxic

https://www.theguardian.com/uk/1999/aug/09/rorycarroll . Or does the biochemistry of Pu particularly depend on the isotope?

It is a complex answer, and heavily depends on decay product chemistry. =3

https://www.ncbi.nlm.nih.gov/books/NBK599402/