There continue to be reports in the literature that suggest a difference in the behavior of239+240Pu and238Pu in some aquatic environments. Plutonium isotopes have been measured in marine samples collected over 3 decades from Enewetak
atoll, one of the sites in the Marshall Islands used by the United States between 1946 and 1958 to test nuclear devices. The
plutonium isotopes originated from a variety of complex sources and could possibly coexist in this environment as different
physical-chemical species. However results indicate little difference in the mobility and biological availability of239+240Pu and238Pu.