The amount of oxygen that can be dissolved in water is a function of temperature, concentration of dissolved solids, and atmospheric pressure. An equation developed by APHA (1985) is used to calculate the saturation concentration of dissolved oxygen:
Oxsat​=exp[−139.34410+Twat,K​1.575701∗105​−(Twat,K​)26.642308∗107​+(Twat,K​)31.243800∗1010​−(Twat,K​)48.621949∗1011​]
4:5.3.2
where Oxsat​ is the equilibrium saturation oxygen concentration at 1.00 atm (mg O2​/L), and Twat,K​ is the water temperature in Kelvin (273.15+°C).