When lithosphere is subducted at a convergent plate boundary, the rock in the lithosphere heats up and the water that was locked in the minerals is released. What do those water atoms do after they are released

In a convergent plate boundary, when the heavier lithospheric plate subducts below the less denser one, it eventually gets heated up when reaches into the deeper zone. Due to this high heating of the plate, the water present in the minerals and rocks of the subducting plate is released and it gradually mixes up with the hot molten rocks.

This eventually leads to partial melting of hot rocks, altering its actual composition, and also causes volcanism when the less denser magma rises upward towards the surface. In addition to this, it can also causes changes in the geothermal gradient in that particular place.