Used as a stable isotopic tracer in metabolic and biochemical research to study reaction mechanisms and pathways involving water. Enables precise tracking of oxygen and hydrogen atoms in processes such as photosynthesis, respiration, and enzymatic reactions. Employed in nuclear magnetic resonance (NMR) spectroscopy for signal enhancement in oxygen-18 labeled compounds. Supports studies in environmental science to trace water movement and origin in hydrological systems. Also utilized in the production of radiopharmaceuticals and in isotopic labeling for mass spectrometry analysis.