[Determination of lead in hydride form in bone biopsies of patients with long past lead poisoning].

Disturbances in the determination of lead by means of flameless atomic absorption by highly pure CaCl2-solutions were demonstrated. To avoid such disturbances a new method for estimation of lead in bone specimens is introduced. Lead is separated in hydride form by adding NaBH4 to the specimens in an acid solution containing tartaric acid and sodium dichromate in a so called metal-hydride-system and then identified by atomic absorption spectrophotometry. For higher concentrations or for mass spectrometric determination of the lead isotope proportions the lead hydride may also be frozen. The hydride method has been used with the estimation of lead in biopsy specimens from the iliac crests of 14 patients who suffered from nephropathies of unknown origin. In addition flameless AAS was employed and the results were controlled. The lead contents in bone specimens from 13 patients with a long history of occupational exposure to lead varied between 126 mumol/kg (26 micrograms/g) and 1,97 mmol/kg (410 micrograms/g) of dried substance. In five control specimens the corresponding values ranged from 19 mumol/kg (4 micrograms/g) to 87 mumol/kg (18 micrograms/g). These findings suggest that nephropathy results from body burden of lead. Additionally hair specimens and nail clippings from several of the above patients were analysed. Control analyses were carried out. The question of lead release from deposits in bone and the connections between nephropathy and exposure to lead are discussed.