The regional distribution of cadmium in the brains of orally exposed adult rats.

Cadmium (Cd) levels were measured in 13 dissected brain regions of adult male rats from 3 treatment groups. Rats (approximately 200 g each) were each fed 10 g/day of diets containing either 20 or 100 micrograms/g (ppm) Cd or control diet to which no Cd was added but contained approximately 0.35 ppm Cd. After 67 days of treatment, the brain of each rat was removed and each was dissected into 13 anatomical regions including olfactory bulbs, frontal cortex, rest of cortex, corpus callosum, hippocampus, amygdalae, corpus striatum, colliculum, tegmentum, thalamus, hypothalamus, pons-medulla, and cerebellum. Cd residues (dry weight) in each sample were determined by flameless atomic absorption spectrophotometry. With exception of the thalamus and olfactory bulbs, each of the brain regions of the 100 ppm Cd rats had more Cd than did those from either the 20 ppm Cd rats or controls which did not differ. There was evidence of selective accumulation of Cd within the olfactory bulbs of control and treated animals. This selective accumulation may be related to anosmia reported in workers with industrial exposure to Cd.

Food analysis for lead using furnace atomic absorption and a L'vov platform.

Furnace atomic absorption is a very sensitive method for determination of lead and other trace metals in a variety of samples, but it is prone to matrix interferences. A major improvement in the method is achieved by the use of a L'vov platform, a small piece of graphite placed inside the furnace tube, onto which the sample solution is pipetted. The temperature of the platform rises more slowly than that of the tube wall during the atomization cycle, and sample vaporization is delayed until the furnace atmosphere is at a high and nearly constant temperature. The resulting atomization behavior is more consistent and less matrix-dependent for numerous analyte elements, including lead. Results are further improved by addition of ammonium phosphate to all samples and standards as a matrix modifier. For example, in comparing analyte sensitivity (slope of the absorbance vs concentration curve) in a variety of food sample types to the sensitivity in dilute HNO3, the average lead response showed 60 +/- 15% suppression due to the sample matrices. Use of the L'vov platform and matrix modifier virtually eliminated the suppression and improved the precision.