DO PERSONS LIVING NEAR A URANIUM PROCESSING SITE HAVE EVIDENCE OF INCREASED SOMATIC-CELL GENE-MUTATIONS - A FIRST STUDY

The objective of this study was to examine if individuals living near a uranium processing site have greater mutagenic damage, as measured b y three mutagenicity assays, compared with subjects unexposed to any n uclear facilities. The design was a cross-sectional exploratory analys is of 112 subjects; 56 volunteer residents were from within a 5-mile r adius of the Fernald Uranium Processing site and 56 'control' subjects were from a geographically separate area unexposed to any known urani um emissions. The groups were constrained to be similar in age and sex composition. The main outcome measures were three human somatic gene mutation assays consisting of the HPRT T-lymphocyte cloning assay to m easure 6-thioguanine resistant lymphocytes; the glycophorin A assay to detect the loss of expression of the M or N allele; and the micronucl eus assay as a marker of chromosomal damage. The results showed no sta tistically significant or quantitatively important differences between groups for all three mutagenicity assays; only the unselected cloning efficiency was statistically significantly different between groups ( 0.42 +/- 0.16 for the Fernald versus 0.35 +/- 0.12 for the comparison groups). In both groups, age was significantly related to HPRT mutant frequency, with a 1.25% rate of increase in mutant frequencies for eac h 1-year gain of age in the Fernald group and a 1.12% rate of increase in mutant frequencies for each 1-year gain of age in the comparison g roup. For the micronucleus data, females had a greater mean micronucle us frequency than mates. In addition, smokers had an increased mean In (natural logarithm) HPRT mutant frequency (3.06 +/- 0.14 for current smokers compared with a mean of 2.72 +/- 0.05 for non-current (i.e. ne ver plus former) smokers). Our results are consistent with the previou sly reported association between sex type and micronucleus frequency, the known relationship between age and T-lymphocyte cloning efficiency and age and HPRT mutant frequency, and verify the wide inter-subject variability for the latter. Finally, we conclude that at a population level, the relationships between current cigarette use and HPRT mutant frequency, and sex type and micronucleus frequency, are stronger than is the association between geographic proximity to a uranium processi ng site and mutagenic abnormalities.