Volume 23, Issue 1 (March 2000)
Oxygen Diffusion Coefficient of Soils at High Degrees of Saturation
The oxygen diffusion coefficient is an essential parameter for design of soil covers over mine waste. This study presents a method for measuring the oxygen diffusion coefficient of soils at high degrees of saturation. The method eliminates measurement errors caused by soil microbial activity, high humidity, and stagnant air in laboratory diffusion cells. Results show that microbial activity is an important factor that causes errors in O2 measurements. Sterilization of soil, utilization of a silica gel-membrane system with oxygen sensors, and minimal stirring in the cell headspace greatly reduce the variability in O2 diffusion coefficient measurements. The variations in estimated O2 diffusion coefficients for the same soil at the same degree of saturation were ±31% about the mean for clayey soil samples and ±10% about the mean for silty soil samples.