Establishing normal values for nickel in human lung disease

People working in the nickel refining industry are known to have a higher c oncentration of nickel in lung tissue than the general population. To be ab le to evaluate a potential nickel exposure from other sources, e.g., weldin g, it is important to have sufficient data on what is normal for a local po pulation. Several local factors such as the content of nickel in air and so il can have a significant impact on this so-called normal value. As almost all surgical equipment contains nickel, the sampling process can in itself be a source of contamination. The scope of this work was to investigate if there was any measurable contamination from the sampling instruments routin ely used in hospitals, and if the presence of a nickel refinery had any eff ect on the nickel content in the lungs of the general population. Autopsy l ung tissue samples were collected in situ from 50 people who had lived in t he county of Vest Agder in Norway. Two samples were collected from each per son; one with a regular scalpel (Swarn-Norton) and forceps, and one with a titanium knife and plastic forceps. None of the persons had any known conne ction to the nickel refinery. The samples were collected at random and no s pecial attention was given to age, sex and place of residence. The autopsie s were performed according to Norwegian law and in understanding with the n ext of kin. The arithmetic mean value fs of nickel was 0.64 +/- 0.56 mu g g (-1) and 0.29 +/- 0.20 mu g g(-1) dry weight, respectively, for samples col lected with a regular scalpel and a titanium knife (P < 0.0001). For people who lived 8 km and closer to the refinery by the time of death, the nickel content was 0.41 +/- 0.19 mu g g(-1) and for those who had lived between 8 and 70 km away from the refinery it was 0.18 +/- 0.13 mu g g(-1) (P<0.015) . No statistical difference was established between results for males and f emales. Previous investigations have shown that the nickel content in lung tissue varies in the so-called normal population. This work has shown that factors such as sampling equipment and place of residence have an impact on the results. It thus demonstrates that reliable background values can pres umably only be obtained by collecting samples from individuals not exposed to known environmental nicker sources and to use nickel-free instruments in the sampling process.