Jamieson, Fausset and Brown on Ezekiel 47:11

11. marshes--marshy places. The region is known to have such pits and marshes. The Arabs take the salt collected by evaporation in these pits for their own use, and that of their flocks.

not be healed--Those not reached by the healing waters of the Gospel, through their sloth and earthly-mindedness, are given over (Re 22:11) to their own bitterness and barrenness (as "saltness" is often employed to express, De 29:23; Psa 107:34; Zep 2:9); an awful example to others in the punishment they suffer (2Pe 2:6).