Radiation-induced chromosomal aberrations among TENORM workers: amang- and ilmenite-processing workers of Malaysia.

The usefulness of peripheral human lymphocytes as a bioindicator for ionizing radiation effect was tested in a survey of Malaysian workers in two industries producing technologically enhanced naturally occurring radioactive material (TENORM). Workers in amang processing plants who have been with the plant for an average of 12.9 years and who were exposed to radioactive dust showed significantly higher frequencies of chromosomal aberration compared to control and even ilmenite-processing workers. Such frequency was not significantly different between workers in ilmenite-processing plant and control. The differences in duration of employment, occupational hygiene, together with the difference in the percentage of 'old' and 'new' aberrations among the groups sampled were used to explain the high chromosomal aberration frequency among amang workers. The presence of significantly high chromosome damage (dicentrics and fragments) in workers who were chronically exposed to doses below 50 mSv per year or 20 mSv per year averaged over 5 years (ICRP, 1991) provided additional experimental data on the dose-effect relationship at these low-dose ranges. The results confirm the usefulness of using human lymphocytes as a bioindicator for chronic exposure to ionizing radiation and in cases where physical radiation detectors are not available.