Speciation of volatile metals and metalloids in the environment is extensively described in literature. To investigate unstable volatile organometallics, online coupling of gas chromatog. with inductively coupled plasma-mass spectrometry was used. Preliminary results for gases of sewage sludge fermn. under thermophilic and mesophilic conditions are compared with metal and metalloid speciation in landfill gases. In each case, 20 L of gas were sampled by cryogenic trapping. Species were identified by element-specific detection either by retention time of stds. or by calcn. of the b.p. correlation. Characteristic of the sepn. is the linear correlation of b.p. (bp/ Deg) vs. retention time (rt/min) (bp = 6.39*rt-109.2, r2 = 0.9926). The amts. of total volatile elements were estd. by semi-quantification. Cd, Sn, Hg, and Pb (sewage gas) and Se, Te, Hg, and Pb (landfill gas) were detd. in ng/m3 levels; As, Sb, Te, and Bi (sewage gas) and As, Sn, Sb, and Bi (landfill gas) in mg/m3 levels.