RADIATION-INDUCED CHROMOSOMAL-ABERRATIONS AMONG TENORM WORKERS - AMANG-PROCESSING AND ILMENITE-PROCESSING WORKERS OF MALAYSIA

The usefulness of peripheral human lymphocytes as a bioindicator for i onizing radiation effect was tested in a survey of Malaysian workers i n two industries producing technologically enhanced naturally occurrin g radioactive material (TENORM). Workers in amang processing plants wh o have been with the plant for an average of 12.9 years and who were e xposed to radioactive dust showed significantly higher frequencies of chromosomal aberration compared to control and even ilmenite-processin g workers. Such frequency was not significantly different between work ers in ilmenite-processing plant and control. The differences in durat ion of employment, occupational hygiene, together with the difference in the percentage of 'old' and 'new' aberrations among the groups samp led were used to explain the high chromosomal aberration frequency amo ng 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 usefuln ess of using human lymphocytes as a bioindicator for chronic exposure to ionizing radiation and in cases where physical radiation detectors are not available.