3.4 Methods for Calculating Selected Parameters in the Mass Loss Expressions

The first order decay/degradation coefficient is related to radioactive decay and degradation.  The RAAS and MEPAS databases contain decay half lives for radionuclides and degradation half lives for some non-radioactive contaminants.  If values of half life are available, the decay constant is calculated as



where    t_1/2i is the decay/degradation half life of contaminant i in any phase (yr).