Electron microscopy and x-ray spectroscopy were used to determine location and type of cadmium biosorption on and in bacteria, some of which produced extracellular polymers. Examined Arthrobacter and Pseudomonas species appear to have detoxification systems that precipitate cadmium internally irrespective of whether or not they excrete polymers. Capsular Klebsiella aerogenes strains showed minimal intracellular uptake but over a 5-100 mg dm-3 Cd range produced the highest net metal removal levels due to significant extracellular adsorption.