The first two temporal moments, i.e., mean value and variance of residence time, are used to characterize nonergodic transport in heterogeneous porous media. Due to the nonergodicity stemming from small initial solute sources relative to the hydraulic conductivity integral scale, only statistical moments of the temporal moments can be obtained. The expected value and variance of the first temporal moment and the expected value of the second temporal moment are derived for both conservative solute and solute subject to sorption governed by linear kinetics. The nonergodic temporal moments incorporating sorption kinetics can be expressed in terms of the corresponding conservative moments and the constant rate parameters. The methodology is exemplified for a two-dimensional aquifer using first-order results for the velocity statistics. The analytical results compare reasonably well with the simulations for a variability in the hydraulic conductivity up to &sgr;ln K2=1. The results indicate that the relative difference between nonergodic and ergodic conditions, expressed through the second temporal moment, clearly is diminished for a kinetically sorbing solute as compared to a conservative one. ¿ American Geophysical Union 1995 |