APPLICATION OF PIXE TO MONITOR THE QUALITY OF SALT FROM SALT FARMING AREAS IN THAILAND

In salt farms of Thailand, saline ground water is pumped up and then solar-evaporated to produce salt for commercial purpose. However, when they continue to precipitate salt in the same pools, the product is stained yellow or brown in color. In order to recover only white salt, workers cut trees and create a new pool next to the old one. Due to this practice, year by year, salt-farming area loses vegetation cover and expands barren section of salt damage. In order to understand the changes of in salt grains, salt was collected and measured by PIXE. The result indicates that manganese is clearly responsible for the coloring, and possibly also irons. This information is expected to base the discussion to stop deforestation in the salt-damaged area.