Occupational exposure to formaldehyde and genetic damage in the peripheral blood lymphocytes of plywood workers.

OBJECTIVES: We sought to clarify the association of occupational formaldehyde exposure with DNA strand breaks, chromosome damage and DNA-protein crosslinks (DPCs) in the peripheral blood (PB) lymphocytes of plywood workers. METHODS: We determined Olive tail moment (OTM) values, micronucleus (MN) frequencies and DPC rates of the PB lymphocytes in 178 workers divided into control and lower and higher exposure groups according to their current formaldehyde exposure levels and examined the association of each end point with formaldehyde exposure levels and with the number of work years. We also examined each end point in an additional 62 workers before and after an 8-hour formaldehyde exposure for validating the association. RESULTS: OTM values increased significantly in the two exposure groups compared with those in the control group (p<0.05 for both) and were associated with increasing formaldehyde exposure levels (ptrend=0.002), while MN frequencies increased with increasing numbers of work years (ptrend<0.001). The dynamic study showed that OTM values and DPC rates increased after an 8-hour formaldehyde exposure compared with those before the exposure (p<0.001, p=0.019, respectively), that, in a dose-dependent manner, OTM values were associated with formaldehyde exposure levels during work hours (p=0.005) and that MN frequencies before and after the 8-hour work exposure were associated with numbers of work years (p=0.029, p<0.001, respectively). CONCLUSIONS: We found a dose-response relationship between the current formaldehyde exposure levels and DNA strand breaks and between duration of exposure and chromosome damage in the PB lymphocytes of plywood workers.

[The increase of micronuclei frequencies of peripheral blood lymphocyte in plywood workers exposed accumulatively to formaldehyde].

OBJECTIVE: To investigate the effects of occupational exposure to formaldehyde on the micronuclei frequencies in peripheral blood lymphocytes of workers. METHODS: Two hundred thirty six plywood workers were divided into 3 exposure groups (low, middle and high) according to internal exposure biomarker (formaldehyde human serum albumin conjugate, FA-HSA), which was detected by ELISA. The concentrations of formaldehyde (FA) in air of two workshops were measure using the high performance liquid chromatography. Cytokinesis-block micronucleus (CBMN) test was used to detect the micronuclei frequencies of peripheral blood lymphocyte in 236 workers. RESULTS: The average concentrations of FA in the low and high exposure workshops were 0.58 +/- 0.20 and 1.48 +/- 0.61 mg/m3, respectively, there was significant difference (P < 0.01). The average concentrations of serum FA-HAS of workers in two workshops were 69.22 +/- 15.37 and 136.29 +/- 89.49 pg/ml, respectively, there was significant difference (P < 0.01). The results of CBMN test showed that the micronucleus frequencies in low, middle and high exposure groups were 1.94 +/- 1.72, 2.10 +/- 1.92 and 2.10 +/- 1.70 per thousand, respectively, there were no significant differences between groups. However, the micronucleus frequencies in accumulative low, middle and high exposure groups were 1.36 +/- 1.36, 2.31 +/- 1.81 and 2.49 +/- 1.92 per thousand, respectively, there were significant differences between different accumulative exposure groups (P < 0.01). The results of correlation analysis indicated that there was a positive correlation between accumulative exposure levels and micronucleus frequencies (r(s) = 0.321, P < 0.01). The accumulative exposure doses may be a risk factor for high micronucleus frequencies in workers exposed to FA (P(trend) = 0.002). CONCLUSION: FA-HSA levels can serve as an internal exposure biomarker for assessing the exposure level of workers exposed to FA. Accumulative formaldehyde exposure resulted in an increase of micronuclei frequencies of peripheral blood lymphocyte in plywood workers.