Increased incidence of chromosomal aberrations in peripheral lymphocytes of retired nickel workers.

Chromosomal aberrations and sister chromatid exchanges were analysed in the peripheral lymphocytes of nine retired nickel refinery workers 4-15 years after the retirement and compared with 11 matched non-nickel exposed controls. None of the controls had previous occupations with known relation to induction of chromosomal aberrations nor sister chromatid exchanges. The groups were equal as to socioeconomic status and environmental factors other than the occupational ones, which could influence the chromosome parameters, were to the largest possible extent excluded. The nickel workers' previous occupational employment involved exposure to inhalation of furnace dust of Ni3S2 and NiO or aerosols of NiCl2 and NiSO4. The concentration of nickel in the working atmospheres has been higher than 1.0 mg/m3 air and the exposure time more than 25 years. The retired nickel workers showed an increased incidence of breaks (p less than 0.001) and gaps (p less than 0.05) but no difference in the incidence of sister chromatid exchanges when compared with the controls.