The Septuagint and the Word Baptizo

The word baptizo is employed in the Septuagint in contexts that likely speak of immersion, but not conclusively. In 2 Kings 514, we read, and Naman went down and dipped himself in the Jordan seven times. Leviticus 1132 says anything on which any of them falls when they are dead shall be unclean. So it would seem because you want to remove impurity from whatever the object is, that you would put it all into the water.