Internal platinum, palladium, and gold exposure in environmentally and occupationally exposed persons

In a pilot study the urinary platinum (Pt), palladium (Pd), and gold (Au) excretion was analyzed in 27 dental technicians, 17 road construction workers and 17 school-leavers using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Detection limits in urine were 0.24 ng/l for Pt and Au and 0.17 ng/l regarding Pd. A standardized questionnaire was used to assess information about kind and degree of contact to these metals, the physical condition of the volunteers and confounding factors. Significant differences between the three study groups were found. The mean Pt, Pd, and Au excretions of the dental technicians were significantly higher than those of the road construction workers and school-leavers. This indicates that the occupational treatment of dental alloys leads to an internal exposure to these metals which is distinctly higher than that from automobile exhaust exposure. Significant differences between Monday morning (pre-shift) and Thursday afternoon (post-shift) urine samples of the dental technicians were not found. The Pt excretion of road construction workers working near a much traveled highway was comparable with that of school-leavers being less (only environmentally) exposed to automobile exhaust. Regarding Pd and Au the road construction workers showed a tendency to higher levels in urine when compared with the school-leavers, but statistically significant differences were not found. The tendency to higher urinary Pd and Au levels in the road-construction workers may be explained by their slightly greater number of noble metal containing artificial dentures, which may cause an additional exposure. A statistically significant effect of age on the urinary noble metal excretion was not detectable.