The role of TOD in water quality monitoring Reflecting the content of organic matter in water Total oxygen demand (TOD) refers to the amount of oxygen required when the reducing substances in water are burned at high temperature to become stable oxides, and the result is measured in mg/L. The TOD value can reflect the amount of oxygen consumed when almost all organic matter in water (including carbon C, hydrogen H, oxygen O, nitrogen N, phosphorus P, sulfur S and other components) are burned to become CO₂, H₂O, NOₓ, SO₂, etc. It is closer to the theoretical oxygen demand value than biochemical oxygen demand (BOD), chemical oxygen demand (COD) and permanganate index, and can more comprehensively reflect the total amount of organic matter in water. https://www.renkeer.com/what-is-cod-bod-toc-tod/