Occupational and environmental risks in and around a smelter in northern Sweden VIII. Three-year follow-up of chromosomal aberrations in workers exposed to lead

Chromosomal aberrations were studied at three different occasions (1976, 1978 and 1979) in ten workers who started to work at a new lead-process (Lead-Kaldo) in 1976. The average blood level of lead showed a significant increase (from 17 to 35μg/100 ml) between 1976 and 1978, followed by a significant decrease (from 35 to 29 μg/ 100 ml) between 1978 and 1979. The frequencies of chromosomal aberrations were found to increase between 1976 and 1979, but the statistical significance of this increase was rather low. In comparison with a reference material of individuals without known occupational exposure to toxic agents, the lead-exposed workers showed a significant increase of chromosomal aberrations in 1979, but not in 1976. Confounding factors, as altered smoking habits and simultaneous exposure to other toxic agents, were discussed, and it was concluded that variations in the frequency of chromosomal aberrations can not with certainty be ascribed to changes in lead exposure.