Precise Anchoring of Fe Sites by Regulating Crystallinity of Novel Binuclear Ni-MOF for Revealing Mechanism of Electrocatalytic Oxygen Evolution.

Bimetallic metal-organic framework (BMOF) exhibits better electrocatalytic performance than mono-MOF, but deciphering the precise anchoring of foreign atoms and revealing the underlying mechanisms at the atomic level remains a major challenge. Herein, a novel binuclear NiFe-MOF with precise anchoring of Fe sites is synthesized. The low-crystallinity (LC)-NiFe0.33 -MOF exhibited abundant unsaturated active sites and demonstrated excellent electrocatalytic oxygen evolution reaction (OER) performance. It achieved an ultralow overpotential of 230 mV at 10 mA cm-2 and a Tafel slope of 41 mV dec-1 . Using a combination of modulating crystallinity, X-ray absorption spectroscopy, and theoretical calculations, the accurate metal sequence of BMOF and the synergistic effect of the active sites are identified, revealing that the adjacent active site plays a significant role in regulating the catalytic performance of the endmost active site. The proposed model of BMOF electrocatalysts facilitates the investigation of efficient OER electrocatalysts and the related catalytic mechanisms.

Developing a Framework for Industrial Noise Risk Management Based on Noise Kurtosis and Its Adjustment.

OBJECTIVES: Noise risk control or management based on noise level has been documented, but noise risk management based on a combination of noise level and noise's temporal structure is rarely reported. This study aimed to develop a framework for industrial noise risk management based on noise kurtosis (reflecting noise's temporal structure) and its adjustment for the noise level. DESIGN: A total of 2805 Chinese manufacturing workers were investigated using a cross-sectional survey. The noise exposure data of each subject included LEX,8h, cumulative noise exposure (CNE), kurtosis, and kurtosis-adjusted LEX,8h (LEX,8h-K). Noise-induced permanent threshold shifts were estimated at 3, 4, and 6 kHz frequencies (NIPTS346) and 1, 2, 3, and 4 kHz frequencies (NIPTS1234). The prevalence of high-frequency noise-induced hearing loss prevalence (HFNIHL%) and noise-induced hearing impairment (NIHI%) were determined. Risk346 or Risk1234 was predicted using the ISO 1999 or NIOSH 1998 model. A noise risk management framework based on kurtosis and its adjustment was developed. RESULTS: Kurtosis could identify the noise type; Kurtosis combining noise levels could identify the homogeneous noise exposure group (HNEG) among workers. Noise kurtosis was a risk factor of HFNIHL or NIHI with an adjusted odds ratio of 1.57 or 1.52 (p < 0.01). At a similar CNE level, the NIPTS346, HFNIHL%, NIPTS1234, or NIHI% increased with increasing kurtosis. A nonlinear regression equation (expressed by logistic function) could rebuild a reliable dose-effect relationship between LEX,8h-K and NIPTS346 at the 70 to 95 dB(A) noise level range. After the kurtosis adjustment, the median LEX,8h was increased by 5.45 dB(A); the predicted Risk346 and Risk1234 were increased by 11.2 and 9.5%, respectively; NIPTS346-K of complex noise at exposure level <80, 80 to 85, and 85 to 90 dB(A), determined from the nonlinear regression equation, was almost the same as the Gaussian noise. Risk management measures could be recommended based on the exposure risk rating or the kurtosis-adjusted action levels (e.g., the lower and upper action levels were 80 and 85 dB(A), respectively). CONCLUSIONS: The kurtosis and its adjustment for noise levels can be used to develop an occupational health risk management framework for industrial noise. More human studies are needed to verify the risk management framework.

Investigation of critical factors influencing the underestimation of hearing loss predicted by the ISO 1999 predicting model.

OBJECTIVE: To analyze factors influencing the underestimation of noise-induced permanent threshold shift (NIPTS) among manufacturing workers, providing baseline data for revising noise exposure standard. DESIGN: A cross-sectional study was designed with 2702 noise-exposed workers from 35 enterprises from 10 industries. Personal noise exposure level(LAeq,8h) and noise kurtosis level were determined by a noise dosimeter. Questionnaires and hearing loss tests were performed for each subject. The predicted NIPTS was calculated using the ISO 1999:2013 model for each participant, and the actual measured NIPTS was corrected for age and sex. The factors influencing the underestimation of NIPTS were investigated. RESULTS: The predicted NIPTS at each test frequency (0.5, 1, 2, 3, 4, or 6kHz) and mean NIPTS at 2, 3, 4, and 6kHz (NIPTS2346) using the ISO 1999:2013 model were significantly lower than their corresponding measured NIPTS, respectively (P < 0.001). The ISO model significantly underestimated the NIPTS2346 by 12.36 dB HL. The multiple linear regression analysis showed that noise exposure level, exposure duration, age, and kurtosis could affect the degree of underestimation of NIPTS2346. The generalized additive model (GAM) with (penalized) spline components showed nonlinear relationships between critical factors (age, exposure duration, noise level, and kurtosis) and the underestimated NIPTS2346.The underestimated NIPTS2346 decreased with an increase in exposure duration (especially over ten years). There was no apparent trend in the underestimated NIPTS2346 with age. The underestimated NIPTS2346 decreased with the increased noise level [especially > 90 dB(A)]. The underestimated NIPTS2346 increased with an increase in noise kurtosis after adjusting for the noise exposure level and exposure duration and ultimately exhibiting a linear regression relationship. CONCLUSIONS: The ISO 1999 predicting model significantly underestimated the noise-induced hearing loss among manufacturing workers. The degree of underestimation became more significant at the noise exposure condition of fewer than ten years, less than 90 dB(A), and higher kurtosis levels. It is necessary to apply kurtosis to adjust the underestimation of hearing loss and consider the applying condition of noise energy metrics when using the ISO predicting model.

Application of the occupational health risk assessment model in predicting the risk of noise-induced hearing loss in noise-polluted manufacturers in southern China.

Objective. This study aimed to evaluate the correlation between occupational noise-induced hearing loss (ONIHL) and noise exposure in different positions within manufacturing facilities that primarily produce electronic devices, wooden furniture and hardware machinery in southern China and to investigate the practical application of the risk assessment model. Methods. Noise exposure data were collected from 115 workers in 10 manufacturing industries in southern China through on-site investigation. Subsequently, sample testing was conducted in accordance with Chinese standards. The 31 job positions investigated were classified into two similar exposure groups (SEGs). The occupational health risk assessment (OHRA) model was used to evaluate the risks of ONIHL in various job positions. Results. More than half of the positions in both groups had noise levels exceeding 85 dB. In both SEGs, male workers exhibited similar risk patterns of acquiring hearing impairment, with a more pronounced and earlier risk of hearing loss compared to female workers. Age was also found to be a risk factor for hearing impairments. Conclusion. The ORHA model demonstrated a positive correlation between noise exposure levels and NIHL. This model can help employers assess job management with noise exposure and take measures to implement an effective risk management system.

Occupational Exposure to Silica Dust and Silicosis Risk in Chinese Noncoal Mines: Qualitative and Quantitative Risk Assessment.

BACKGROUND: Despite increasing awareness, silica dust-induced silicosis still contributes to the huge disease burden in China. Worryingly, recent silica dust exposure levels and silicosis risk in Chinese noncoal mines remain unclear. OBJECTIVE: We aimed to determine recent silica dust exposure levels and assess the risk of silicosis in Chinese noncoal mines. METHODS: Between May and December 2020, we conducted a retrospective cohort study on 3 noncoal mines and 1 public hospital to establish, using multivariable Cox regression analyses, prediction formulas of the silicosis cumulative hazard ratio (H) and incidence (I) and a cross-sectional study on 155 noncoal mines in 10 Chinese provinces to determine the prevalence of silica dust exposure (PDE), free silica content, and total dust and respirable dust concentrations. The qualitative risk of silicosis was assessed using the International Mining and Metals Commission's risk-rating table and the occupational hazard risk index; the quantitative risk was assessed using prediction formulas. RESULTS: Kaplan-Meier survival analysis revealed significant differences in the silicosis probability between silica dust-exposed male and female miners (log-rank test χ21=7.52, P=.01). A total of 126 noncoal mines, with 29,835 miners and 4623 dust samples, were included; 13,037 (43.7%) miners were exposed to silica dust, of which 12,952 (99.3%) were male. The median PDE, free silica content, total dust concentration, and respirable dust concentration were 61.6%, 27.6%, 1.30 mg/m3, and 0.58 mg/m3, respectively, indicating that miners in nonmetal, nonferrous metal, small, and open-pit mines suffer high-level exposure to silica dust. Comprehensive qualitative risk assessment showed noncoal miners had a medium risk of silicosis, and the risks caused by total silica dust and respirable silica dust exposure were high and medium, respectively. When predicting H and I over the next 10, 20, and 30 years, we assumed that the miner gender was male. Under exposure to current total silica dust concentrations, median I10, I20, and I30 would be 6.8%, 25.1%, and 49.9%, respectively. Under exposure to current respirable silica dust concentrations, median I10, I20, and I30 would be 6.8%, 27.7%, and 57.4%, respectively. These findings showed that miners in nonmetal, nonferrous metal, small, and open-pit mines have a higher I and higher qualitative silicosis risk. CONCLUSIONS: Chinese noncoal miners, especially those in nonmetal, nonferrous metal, small, and open-pit mines, still suffer high-level exposure to silica dust and a medium-level risk of silicosis. Data of both total silica dust and respirable silica dust are vital for occupational health risk assessment in order to devise effective control measures to reduce noncoal mine silica dust levels, improve miners' working environment, and reduce the risk of silicosis.

Application of multiple occupational health risk assessment models in occupation health risk prediction of trichloroethylene in the electroplating and electronics industries.

Objectives. This study assessed the occupational health risks of work group exposure to trichloroethylene (TCE) in the electroplating and electronics industries in China. Methods. The UK Control of Substances Hazardous to Health (COSHH) Essential, the US Environmental Protection Agency (EPA) and the Singapore and the Chinese semiquantitative risk assessment models were used to assess the risks of TCE. Twenty degreasing groups and 14 cleaning groups were recruited in the companies selected. Results. The concentrations of TCE in 66.7% of the cleaning groups and 35.0% of the degreasing groups exceeded the permissible concentration time-weighted average (PC-TWA) in China, and the concentrations of TCE in 100.0% of the cleaning groups and 70.0% of the degreasing groups exceeded the permissible concentration short-term exposure limit (PC-STEL) in China. Over 60.0% of the work groups were evaluated at high risk and over half of the work groups were evaluated at high cancer risk by the risk assessment models. Conclusion. Most work groups exposed to TCE in the electroplating and electronics industries in China are at high risk. The cleaning groups may have a higher risk for TCE exposure. The Chinese exposure index method and the synthesis index method are more practical than the other methods.

Occupational health risk assessment of workplace solvents and noise in the electronics industry using three comprehensive risk assessment models.

Background: Occupational hazards such as solvents and noise in the electronics industry are serious. Although various occupational health risk assessment models have been applied in the electronics industry, they have only been used to assess the risks of individual job positions. Few existing studies have focused on the total risk level of critical risk factors in enterprises. Methods: Ten electronics enterprises were selected for this study. Information, air samples and physical factor measurements were collected from the selected enterprises through on-site investigation, and then the data were collated and samples were tested according to the requirements of Chinese standards. The Occupational Health Risk Classification and Assessment Model (referred to as the Classification Model), the Occupational Health Risk Grading and Assessment Model (referred to as the Grading Model), and the Occupational Disease Hazard Evaluation Model were used to assess the risks of the enterprises. The correlations and differences between the three models were analyzed, and the results of the models were validated by the average risk level of all of the hazard factors. Results: Hazards with concentrations exceeding the Chinese occupational exposure limits (OELs) were methylene chloride, 1,2-dichloroethane, and noise. The exposure time of workers ranged from 1 to 11 h per day and the frequency of exposure ranged from 5 to 6 times per week. The risk ratios (RRs) of the Classification Model, the Grading Model and the Occupational Disease Hazard Evaluation Model were 0.70 ± 0.10, 0.34 ± 0.13, and 0.65 ± 0.21, respectively. The RRs for the three risk assessment models were statistically different (P < 0.001), and there were no correlations between them (P > 0.05). The average risk level of all of the hazard factors was 0.38 ± 0.18, which did not differ from the RRs of the Grading Model (P > 0.05). Conclusions: The hazards of organic solvents and noise in the electronics industry are not negligible. The Grading Model offers a good reflection of the actual risk level of the electronics industry and has strong practicability.

[Effects of noise exposure level on the relationship between SNPs of SOD1 and the susceptibility to noise-induced hearing loss (NIHL)].

OBJECTIVE: To explore the effects of noise exposure level and cumulative noise exposure (CNE) on the relationship between rs2070424 and rs10432782 SNPs in SOD1 and the susceptibility to noise-induced hearing loss (NIHL). METHODS: A case-control study was performed for investigating the effects of environmental risk factors on the susceptibility to NIHL in 201 sensitive workers and 202 resistant workers.A questionnaire was utilized to investigate the occupational health and to identify the occupational risk factors. The noise exposure levels were detected according to the Chinese standard Measurement of noise in the workplace (GBZ/T 189.8-2007). The peripheral blood samples (5 ml blood for each sample) were from sensitive workers and resistant workers. Genomic DNA was extracted on the basis of the standard procedures of Takara kit. SNPs were detected using standard procedures of TaqMan probe allele identification method. RESULTS: In group exposed to 85 - 92 dB noise (A), the risk of NIHL in the subjects with the AA genotype of rs2070424 was lower than that in the subjects with the GG genotype, OR = 0.37 (95%CI: 0.17∼ 0.80). In group exposed to > 82 dB CNE (A), the AA genotype of rs2070424 is a protective factor of NIHL, as compared with the GG genotype, OR = 0.25 (95%CI: 0.09 ∼ 0.70). In group exposed to 85 - 92 dB noise (A), the risk of NIHL in the subjects with the GG genotype of rs10432782 was compared with the risk of NIHL in the subjects with the TT genotype, OR = 3.17 (95%CI: 1.16 ∼ 6.89). The GT genotype was compared with TT genotype, OR = 2.39 (95%CI: 1.16 ∼ 4.97). In group exposed to 75 ∼ 82 dB CNE (A), the risk of NIHL in the subjects with the GG genotype was compared with the risk of NIHL in the subjects with the TT genotype, OR = 2.35 (95%CI: 0.96 ∼ 5.72), P = 0.06. The GG genotype may bea risk factor of NIHJ. CONCLUSION: The noise exposure level and CNE may influence the relationship between rs2070424, rs10432782 SNPs in SOD1 and noise-induced hearing loss.

The relationship between occupational stress and job burnout among female manufacturing workers in Guangdong, China: a cross-sectional study.

This study aims to investigate the relationship between occupational stress and job burnout in female manufacturing workers. A random sample of 1081 female workers in electronic manufacturing in Guangdong Province participated in the present study. An anonymous self-administered questionnaire that covered social-demographic characteristics, the Chinese version of the Job Content Questionnaire, the Chinese version of the Effort-reward Imbalance Questionnaire, and the Maslach Burnout Inventory for the General Survey, was used to assess occupational stress and job burnout. Independent sample t-test, one-way analysis of variance (ANOVA), correlation analysis, hierarchical multiple regression analysis and logistic regression analysis were used in data analysis. Occupational stress was positively correlated with emotional exhaustion and depersonalization and negatively correlated with personal accomplishment. After adjusting for sociodemographic characteristics, job strain was a risk factor for emotional exhaustion (OR = 2.27, 95% CI: 1.61-3.20) and depersonalization (OR = 1.96 95% CI: 1.45-2.64). Female workers with high effort-reward imbalance had an increased risk of depersonalization (OR = 1.96, 95% CI: 1.33-2.90). Furthermore, female workers with high overcommitment had an increased risk of emotional exhaustion (OR = 3.07, 95% CI: 2.06-4.58) and depersonalization (OR = 2.83, 95% CI: 1.92-4.17), while higher social support reduced the risk of emotional exhaustion (OR = 0.37, 95% CI: 0.26-0.53). The job burnout of female manufacturing workers is significantly correlated with their occupational stress. Higher job strain and overcommitment might be important contributors to job burnout. Increased worker social support can reduce job burnout.

The prediction of occupational health risks of benzene in the printing industry through multiple occupational health risk assessment models.

Background: Benzene poisoning is a common occupational poisoning event in the printing industries. Up to now there is still a lack of research data on risk assessment of benzene operations in enclosed workshops. It is crucial to assess the risk level of these positions and put forward effective measures and suggestions. Methods: The information of selected companies and air samples were collected through on-site investigation, data collation and sample testing were carried out according to the requirements of Chinese standards. The Control of Substances Hazardous to Health (COSHH) Essential, the EPA non-carcinogenic risk assessment model, the Singapore exposure index method and the Chinese semi-quantitative risk assessment models were used to assess the risks of benzene. Results: The exposed groups all worked more than 8 h per day, and the cleaning, pasting, and packaging groups used general ventilation rather than local ventilation. 28.6% of the printing group and 16.7% of the pasting group had benzene concentrations that exceeded the permissible concentration-time weighted average (PC-TWA) in China. Over 60.0% of the work groups were evaluated at high risk and over 20% of the work groups were evaluated at high cancer risk by the risk assessment models. Conclusion: The Chinese exposure index method and the synthesis index method may have a stronger practicability. The printing and pasting groups may have a higher risk for benzene exposure. It is necessary to increase protective measures and strengthen occupational hygiene management to reduce risks.

Application of multiple occupational health risk assessment models in the prediction of occupational health risks of n-Hexane in the air-conditioned closed workshop.

Background: n-Hexane (NH) poisoning is a common occupational poisoning in the hardware and electronics industries. However, there is few research data on risk assessment of positions using NH in enclosed workshops. It is very important to assess the risk level of these positions and put forward effective measures and suggestions. Methods: The information of selected companies and air samples were collected through on-site investigation, and data collation and sample testing were carried out according to the requirements of Chinese standards. The Control of Substances Hazardous to Health (COSHH) Essential, the EPA non-carcinogenic risk assessment model, the Singapore exposure index method and the Chinese semi-quantitative risk assessment models were used to assess the risks of NH. Results: The working hours of the exposure groups, printing groups and packing groups all exceeded 9 h per day, less than 30% of each similar exposure groups (SEG) was equipped with the local exhaust ventilation, and 11.1% of the cleaning group and 8.3% of the printing group had NH concentrations in the air that exceeded the Chinese occupational exposure limit (OEL). In the EPA non-carcinogenic risk assessment model, each SEG was evaluated at high risk. In the Chinese semi-quantitative risk assessment models, all of the work groups of exposure groups, 91.7% of the work groups of printing groups, 77.8% of the work groups of printing groups, and 57.1% of the work groups of printing groups were evaluated at unacceptable risk. More than 40.0% of the work groups of printing groups and cleaning groups and over 20.0% of the work groups of exposure groups and packing groups were evaluated at high risk in the Chinese semi-quantitative risk assessment models. Conclusions: The Chinese exposure index method and the synthesis index method may have a stronger practicability. Some work groups that use NH in air-conditioned enclosed workshops in China, especially the cleaning groups, are still in a high-risk state. It is necessary to increase protective measures and strengthen occupational hygiene management to reduce risks.

[Association between SNPs in SOD1 and noise-induced hearing loss in Chinese Han population].

OBJECTIVE: To observe the association between SNPs in SOD1 (rs1041740, rs2070424, rs10432782 and rs4998557) and noise-induced hearing loss in Chinese Han population. METHODS: A case-control study was used to study the effects of environmental risk factors on the susceptibility to noise induced hearing loss (NIHL) in 201 sensitive workers and 202 resistant workers. A questionnaire was designed to carry out an investigation, and an occupational health survey was used to identify the occupational risk factors. Genomic DNA was extracted from peripheral blood cells using standard procedures of Takara kit, and 5 ml blood was from each subject. SNPs were detected using standard procedures of TaqMan probe allele identification method. RESULTS: In SOD1 gene, the A allele of rs2070424 was a protective factor of NIHL, compared with the G allele (OR = 0.67, 95%CI: 0.50 approximately 0.88). The risk with NIHL in subjects with AA genotype was significantly lower than that in subjects with GG genotype (OR = 0.48, 95%CI: 0.26 approximately 0.79). After adjusting the confusion factors, OR was 0.44 and 95%CI was 0.25 approximately 0.78. CONCLUSION: In Chinese Han population, the SNP of rs2070424 in SOD1 may be associated with the susceptibility to NIHL.

[Mechanism study of adaptive response in high background radiation area of Yangjiang in China].

OBJECTIVE: To study the adaptive response mechanisms in high background radiation area (HBRA) among Yangjiang local people through gene and protein expression of receptor for advanced glycation end products (RAGE) and S100A6 in peripheral blood and sputum in inhabitants of HBRA. METHODS: A total of 53 male inhabitants were selected from HBRA in Yangjiang as the exposure group, while 53 male inhabitants were selected from Enping (control area, CA)as the control group. The content of RAGE and S100A6 gene and protein were detected by RT-PCR and Western blotting assay. Thermo luminescent dosemeter(TLD) assay was used to measure the outside dose and estimate the effective dose. RESULTS: The effective dose in CA and HBRA was respectively 1.95 mSv and 6.24 mSv, which was 3 fold difference. Compared with CA, RAGE and S100A6 expression were significantly reduced in both gene and protein level in HBRA. The relative median mRNA expression of RAGE and S100A6 in peripheral blood were respectively 0.28, 1.06 and 0.16, 0.79 in CA and HBRA group, there was significance (with analysis Z values of -2.587 and -2.328 respectively, P < 0.05) with Wilcoxon rank test. For the protein of sputum, the relative median expression were respectively 2.98, 2.25 and 0.53, 0.47 with significant difference (with analysis Z values of -2.201 and -2.366 respectively, P < 0.05) by Wilcoxon rank test. CONCLUSION: The low expression of RAGE and S100A6 in HBRA group might be correlated with the adaptive response and the low mortality of cancer in HBRA.

Evidence for Adaptive Response in a Molecular Epidemiological Study of the Inhabitants of a High Background-radiation Area of Yangjiang, China.

Our previous studies have shown that cancer mortality in high background-radiation areas of China was lower than that in a control area, indicating the possibility of an adaptive response in high background-radiation areas. Our aim is to determine the effect of low-dose radiation on the level of DNA oxidative damage, DNA damage repair, antioxidant capacity, and apoptosis in high background-radiation area and control area populations of Guangdong through a molecular epidemiological study in order to identify adaptive response. Blood samples were collected from male residents aged 50 to 59 y in a high background-radiation area (Yangjiang) and a control area (Enping), and activities of superoxide dismutase, glutathione, catalase, total antioxidant capacity, and expression of O6-methylguanine-DNA methyltransferase gene (MGMT), human 8-oxoguanine DNA N-glycosylase 1 gene (hOGG1), proapoptotic genes and antiapoptotic genes, oxidative-stress-related genes, as well as concentrations of 8-OHdG, TrxR, HSP27, and MT-COX2 were determined. The activities of antioxidative enzymes, relative mRNA expression level of DNA repair genes, antiapoptotic genes, oxidative-stress-related genes HSPB1 and MT-COX2, and the concentration of antioxidant index TrxR in the high background-radiation area population increased significantly compared to the control population (p < 0.05). The relative mRNA expression level of proapoptotic genes and the concentration of DNA oxidative damage index 8-OHdG were significantly lower in the high background-radiation area compared to those in the control area (p < 0.05). In conclusion, under long-term, natural, high background, ionizing radiation, DNA damage-repair capacity and antioxidant capacity of inhabitants in the high background-radiation area may be enhanced. Additionally, it could induce up regulation of cell-survival gene expression and down regulation of apoptotic gene expression. It might be speculated that enhanced antioxidant and DNA repair capacity and inhibition of apoptosis might play important roles in adaptive response of low-dose radiation in high background-radiation areas.

Aberrant promoter methylation of p16(INK4a) and O(6)-methylguanine-DNA methyltransferase genes in workers at a Chinese uranium mine.

To find the possible association of gene methylation of p16(INK4a) and O(6)-Methylguanine-DNA Methyltransferase (O(6)-MGMT) with occupational exposure to radon, 91 male miners from a uranium mine in China were divided into 4 groups according to the cumulative doses of radon exposure from 2 to 425 WLM (working-level months), and aberrant promoter methylation of p16(INK4a) and O(6)-MGMT genes in sputum samples was determined by a specific PCR assay. The results revealed that the methylated rates of 16(INK4a) gene (z=2.844, P=0.005) and O(6)-MGMT gene (z=3.034, P=0.002), and the total methylated rate of these two genes (z=3.859, P=0.0001) increased significantly with the cumulative doses of radon among the miners. This methylation could be applied as a potential marker for the detection of early DNA damage induced by occupational radon exposure.

[p16 and MGMT gene methylation in sputum cells of uranium workers].

OBJECTIVE: To study the methylation of O-6-methylguanine-DNA methyltransferase (MGMT) and p16 gene in the sputum cells of radon-exposed population. To provide the experimental base for finding the molecular biomarker of the high risk population of the radon-induced lung cancer. METHODS: 91 radon-exposed workers were divided into 4 groups, high dosage group (> 120 WLM), middle dosage group (between 60 and 120 WLM), low dosage group (between 30 and 60 WLB) and lower dosage group (between 2 and 30 WLM) according to the accumulated exposure dosage of the radon daughters. The abnormal methylation of p16 and MGMT gene in the sputum cells of the population in the four groups was detected with the methylation specific PCR (MSP). RESULTS: There was significantly upward trend for the p16 gene methylation rate (0.00%-20.00%), the MGMT gene methylation rate (0.00%-28.00%) and the total methylation rate (0.00%-40.00%) with the increase of the accumulated exposure dosage of the radon daughters (P < 0.01). CONCLUSION: The methylation of p16 and MGMT gene is related to the accumulate exposure dosage of the radon daughters.