Fig. 6. Dissipation of 1 mg [1,2,6,7–3H(N)]-testosterone/kg autoclaved loam soil incubated at 30°C. Total radioactivity in extracts was determined by liquid scintillation counting (LSC), while high performance liquid chromatography (HPLC)–radioactivity detection (RD) was used to determine the distribution of radioactivity in testosterone or 4-androstene-3,17-dione, the only detectable transformation product. Androgenic activity in soil extracts was determined with the yeast androgen receptor gene transcription assay.