Analyses (glc) of extracts from whole cultures (medium and microorganisms) gave the same 'fingerprint' chromatogram as the control, indicating that toxaphene was not degraded even after extended periods of time. The insecticide was also added to autoclaved cultures of bacteria, fungi, and algae which sorbed as much or a little more pesticide than the viable cells. Therefore, the observed sorption was not the result of a metabolically active process. Desorption of toxaphene was studied by harvesting bacterial cells that had reached equilibrium in the pesticide solution and resuspending them in medium containing no pesticides. Samples were centrifuged, and extracted, and the supernatant was analyzed for pesticide as described. Desorption equilibrium was achieved in as short a time as was equilibrium in the sorption studies and the distribution coefficient were the same.