A novel method, called “pyromineralization,” has been developed for the determination of heavy metals in biological samples at ppb and ppm levels. The generic term “mineralization” refers to a pretreatment aimed attransferringtrace metal constituents of samples which are insoluble in waterquantitatively into aqueous solution obviating any contamination. The sample was dissolved at 470°C in a LiCl-KCl eutectic melt under a flowing supernatant atmosphere of oxygen and gaseous hydrochloric acid. Subsequent cooling to room temperature and dissolution in an appropriate volume of water yielded a supporting electrolyte containing 2.5 M alkali chloride, which was ideally suited for the quantitation of copper, lead, cadmium, zinc, chromium, manganese, nickel, and cobalt in sewage sludge specimens by differential pulse polarography and anodic stripping voltammetry.