Health examination and chromosome aberration analysis of residents living in 60Co-contaminated rebar buildings.

PURPOSE: To elucidate the results of health examination and chromosome aberration analysis of residents living in (60)Co-contaminated rebar buildings.

MATERIAL AND

METHODS

Medical surveillance including peripheral blood analysis, urine analysis, chest X-ray, blood biochemical analysis, electrocardiography, thyroid function test and physical examination was performed on 189 residents within 6 months after disclosure of radiation exposure. The annual dose for this group of residents varied from 2 to 95 mSv year(-1) (mean+/-1 SD = 18+/-21 mSv year(-1)) above the background exposure of the Taiwanese population. For chromosome analysis, 500-671 lymphocytes were scored for 136 residents, and the numbers of dicentrics and rings were counted and analysed.

RESULTS

Medical surveillance showed that the most frequent abnormalities were elevation of the erythrocyte sedimentation rate occurring in 14.8% of those examined. Reduction of the negative charge on erthrocytes by ionizing radiation may cause an elevation of erythrocyte sedimentation rate. Statistical analysis of chromosome aberration data showed that the mean dicentric frequency for radiation-contaminated building residents (0.69+/-0.93 SD) was significantly higher than those for controls (0.33+/-0.49) (p <0.01).

CONCLUSIONS

No radiation effects were found in the preliminary health examination. However, lymphocyte chromosome analysis of the radiation-contaminated building residents showed that prolonged low-dose-rate gamma exposure induced cytogenetic changes in humans.