Distribution and elimination of palladium in male wistar rats following 14-day oral exposure in drinking water

The Pd tissue distribution and elimination in rats following oral exposure in drinking water of dipotassium hexachloropalladate at doses of 100 or 250 ng/ml for 14 d were determined. The sector field inductively coupled plasma mass spectrometry used for Pd quantification showed the adequate sensitivity (10 ng/l) and accuracy (96-105%), and all the more in consideration of the very low levels of Pd accumulated. Tissues were taken and analyzed after 14 d. The tissue containing the highest Pd concentration was the kidney (4 ng/g dry weight in controls and 75 ng/g dry weight at the maximum dose), with left and right kidneys showing a comparable accumulation. The Pd kidney levels rose, but not significantly, with the administered dose. None of the other organs (liver, lung, spleen, adrenal glands, and bones) appeared to accumulate Pd, even at the highest dose. At the 250-ng/ml dose, small amounts of Pd were found in serum (0.27 ng/ml vs. 0.19 ng/ml in controls), while they were higher in urine (1.2 ng/ml vs. 0.16 ng/ml in controls) and in feces (3,231 ng/g dry weight vs. 69 ng/g dry weight in controls). Feces were the main excretion route for Pd, with a significant linear correlation with exposed dose, which is likely due to low intestinal absorption of Pd.