Spin-echo and free induction decay (FID) detected electron paramagnetic resonance were applied to detect free D atoms in the pulse radiolysis of CD4 in liquid argon, krypton, xenon, and nitrogen at 77-160 K. The D atoms were polarized through chemically induced dynamic electron polarization in random encounters. The decay of polarization was essentially independent of the fraction of methane (1-70 mol %) and the temperature of the liquid solution. Analysis of the polarization decay kinetics and the D atoms yield suggests that ion reactions dominate over energy transfer reactions in these mixtures (except for xenon solutions). In solid CD4-Ar mixtures a satellite resonance line of unusually polarized D atoms was observed. This indicates microheterogeneous nature of these solid mixtures and explains anomalous chemistry observed in the media.