The Lord of the Rings Wikia notes the following about Mordor following Sauron's defeat:
After the ultimate defeat of Sauron, Mordor became mostly empty again as the orcs inside it fled or were killed. Crippled by thousands of years of abuse and neglect, but capable of sustaining life, the land of Mordor was given to the defeated foes of Gondor as a consolation, as well as to the freed slaves of Nurn who were formerly forced to farm there to feed the armies of Mordor.
[MORDOR - LOTR WIKIA]
Besides the Nurn, who else received ownership of Mordor following the War of the Ring? As well, was Mordor ever decontaminated, or was it just too poisonous and toxic after thousands of years of evil to ever be recultivated?
I'm looking for a canon answer, meaning the actual novels or any of J.R.R. Tolkien's supplemental books, papers, or letters.