While working near a radioactive mine, workers usually wear heavy plastic suits. these suits protect them from all but

gamma radiation would be the best answer. Alpha particles can be stopped by air. UV radiation can be halted by a layer of clothing or insulator. Beta particles can be ceased by the plastic suit. Just gamma radiation can enter the substantial suit. It must be halted by thick dividers of lead or cement.

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.