Assessment of DNA/Chromosome Damage in the Peripheral Blood Lymphocytes of Workers Exposed to Indium Compounds

This study was conducted to investigate possible genotoxic effects resulting from occupational exposure to indium compounds. We performed a cytogenetic analysis of peripheral blood lymphocytes gathered from 57 individuals exposed to indium at an indium ingot production plant in Guangxi, China, and compared the results with those obtained from 63 control subjects. The lymphocytes from both groups were examined in the chromosomal aberrations (CAs) assay, cytokinesis-block micronucleus (CBMN) assay, and single-cell gel electrophoresis (comet) assay. Samples of personal breathing zone air were collected throughout the work shift of each subject. Blood and urine samples were collected before and after each work shift on the same day as the air samples were collected. Our assay results showed that workers in the indium production plant were exposed to significantly higher levels of indium (median exposure, 8.00 mu g/m(3)) than the control subjects. Also, higher concentrations of urinary indium (U-In) were found in the exposed workers than the control subjects. When compared with the control subjects, the exposed workers showed higher levels of DNA damage as detected by the comet assay (tail length and TDNA%), significantly higher frequencies of CAs/100 cells, and increased CBMN frequencies. Moreover, the mean CBMN frequency in the non-smokers exposed to indium was significantly higher than that in the non-smoker control subjects (3.14 vs 1.00, respectively; P <.01). U-In levels, comet assay, CBMN, and CA test proved to be the most sensitive biological markers for detecting occupational exposure to indium compounds and can also be used to assess the health risks of the exposed workers.