Association between plasma BPDE-Alb adduct concentrations and DNA damage of peripheral blood lymphocytes among coke oven workers

The Comet Assay as a Tool in Human Biomonitoring Studies of Environmental and Occupational Exposure to Chemicals-A Systematic Scoping Review

Biomonitoring of human populations exposed to chemical substances that can act as potential mutagens or carcinogens, may enable the detection of damage and early disease prevention. In recent years, the comet assay has become an important tool for assessing DNA damage, both in environmental and occupational exposure contexts. To evidence the role of the comet assay in human biomonitoring, we have analysed original research studies of environmental or occupational exposure that used the comet assay in their assessments, following the PRISMA-ScR method (preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews). Groups of chemicals were designated according to a broad classification, and the results obtained from over 300 original studies (n = 123 on air pollutants, n = 14 on anaesthetics, n = 18 on antineoplastic drugs, n = 57 on heavy metals, n = 59 on pesticides, and n = 49 on solvents) showed overall higher values of DNA strand breaks in the exposed subjects in comparison with the unexposed. In summary, our systematic scoping review strengthens the relevance of the use of the comet assay in assessing DNA damage in human biomonitoring studies.

Polycyclic aromatic hydrocarbons in particulate matter and serum club cell secretory protein change among schoolchildren: A molecular epidemiology study

Airborne particulate matter (PM) is a complex mixture containing various kinds of harmful components. Exposure to air PM is associated with childhood respiratory disease, but epidemiological data are limited concerning the circulating respiratory injury protein on the etiology of childhood respiratory disease. Specifically, the role of PM toxic components or its biological effective dose (adduct) in respiratory injury remains unclear. To demonstrate the dose-response relationship and the main mechanism on circulating club cell secretory protein (CC16) from PM compositions among children, we enrolled 273 boarding schoolchildren in China, including 110 and 163 children of whom were in the low- and high-PM exposed areas, respectively. In this study, we measured the internal exposure levels, including serum polycyclic aromatic hydrocarbons (PAH) adduct, urinary metals, and AhR expression, and detected the serum CC16 level as a lung injury marker. Environmental tobacco exposure in children was assessed by urinary cotinine. We found that significantly higher levels of serum CC16, benzo[a]pyridin-7,8-dihydroglycol-9,10-epoxide (BPDE)-albumin adduct, urinary molybdenum, selenium, arsenic, cadmium and barium, and lower level of AhR expression in high-PM exposed group. There was a good association between serum BPDE-albumin adduct and CC16 (β = 0.222, P = 0.006). There was no association on urinary metals and serum CC16. BPDE-albumin adduct was directly associated with serum CC16 alternation [direct effect = 0.2044, 95% confidence interval (CI) = (0.0426, 0.36)]. PM could cause serum CC16 increased in children. PAH and its adduct might play a key role in lung injury during PM exposure.

Particulate matter air pollution and the expression of microRNAs and pro-inflammatory genes: Association and mediation among children in Jinan, China

Exposure to particulate matter (PM) has been associated with increased risk of various diseases, possibly through its effect on inflammatory response. MicroRNAs (miRNAs), an epigenetic mechanism regulating gene expression, can affect the expression of pro-inflammatory genes. However, few epidemiological studies have examined the impact of PM on inflammation-related miRNAs and their target mRNAs, especially among vulnerable population. We recruited 160 and 113 children from areas with different PM level in Jinan, China. We measured benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts in serum and the expression of 5 candidate miRNAs involved in inflammation regulation and 7 pro-inflammatory genes predicted to be their targets in leukocytes. Generally, children in the polluted area had higher miRNAs and lower mRNAs expression than those in the control area. An interquartile increase of BPDE-Alb adducts was associated with 12.66 %, 14.13 %, and 12.76 % higher of let-7a, miR-146a-5p, and miR-155-5p, as well as 21.61 %, 20.16 %, and 12.49 % lower of IL-6, CXCL8, and TLR2 mRNAs at false discovery rate<0.05, respectively. Additionally, let-7a, miR-146a-5p, and miR-155-5p were found to mediate the associations of BPDE-Alb adducts with IL-6 and/or TLR2 expression. Our findings suggested that PM exposure might attenuate inflammatory response among children in China, which was partly mediated by miRNAs regulating pro-inflammatory genes.

Environmental Monitoring of PAHs Exposure, Biomarkers and Vital Status in Coke Oven Workers

A follow-up study of a cohort of workers from a coke plant compared with a control group from the same industrial area was conducted in 2019. The recruitment and environmental and biomarker measurements were performed during 1993/1994. The environmental concentrations of polycyclic aromatic hydrocarbons (PAH), B(a)P, pyrene and nitro-PAH were measured. Personal data were collected via an individual semi-structured questionnaire by a trained physician. All biomarkers were measured after a specific blood drawing for every test. Significant risks (ORs) were observed for nitro-PAH (≥0.12 µg/m³) [OR = 7.96 (1.01–62.82)], urinary 1-hydroxypyrene (1-OHpy) (≥0.99 µmoles/moles of creatinine) [OR = 11.71 (1.47–92.90)], PAH DNA adducts (P³²) (≥2.69 adducts/10⁸ nucleotides) [OR = 5.46 (1.17–25.58)], total nitro-PAH hemoglobin adducts (≥161.68 fg/µg of Hb) [OR = 5.92 (1.26–27.86)], sister chromatid exchange (SCE) with TCR (≥377.84 SCE/cell chromosomes) [OR = 13.06 (3.95–93.10)], sister chromatid exchange with T (≥394.72 total SCE) [OR = 13.06 (3.95–93.10)], and sister chromatid exchange with X (≥8.19 mean SCE) [OR = 13.06 (3.95–93.10)]. Significant risk of death for all causes and chromosomal aberrations (48 h) (OR = 7.19 [1.19–43.44]) or micronuclei in culture at 48 h (OR = 3.86 [1.04–14.38]) were also found.

Association between occupational heat stress and DNA damage in lymphocytes of workers exposed to hot working environments in a steel industry in Southern India

Occupational heat stress apart from adverse heat-related health consequences also induces DNA damage in workers exposed to high working temperatures. We investigated the association between chronic heat exposures and Micronuclei (MN) frequency in lymphocytes of 120 workers employed in the steel industry. There was a significant increase in the MN-frequency in exposed workers compared to the unexposed workers (X² = 47.1; p < 0.0001). While exposed workers had higher risk of DNA damage (Adj. OR = 23.3, 95% CI 8.0-70.8) compared to the unexposed workers, among the exposed workers, the odds of DNA damage was much higher for the workers exposed to high-heat levels (Adj. OR = 81.4; 95% CI 21.3-310.1) even after adjusting for confounders. For exposed workers, years of exposure to heat also had a significant association with higher induction of MN (Adj. OR = 29.7; 95% CI 2.8-315.5). Exposures to chronic heat stress is a significant occupational health risk including damages in sub-cellular level, for workers. Developing protective interventions to reduce heat exposures is imperative in the rising temperature scenario to protect millions of workers across the globe.

S phase arrest in lymphocytes induced by urinary 1-hydroxypyrene and alcohol drinking in coke oven workers

Arrest of the cell cycle after DNA damage is believed to promote DNA repair. We aim to investigate the main factors affecting cell cycle arrest of lymphocytes in coke oven workers. A total of 600 workers were included in this study, and their urinary levels of four polycyclic aromatic hydrocarbons (PAH) metabolites, 8-hydroxydeoxyguanosine (8-OHdG), and cell cycle distribution were determined. Urinary PAH metabolites were significantly increased in coke oven workers ( p < 0.01). It was found that only urinary 2-hydroxynaphthalene and 1-hydroxypyrene showed significant positive linear dose–response effects on 8-OHdG in this study population ( ptrend = 0.025 and 0.017, respectively). The dose–response effect was also observed for smoking and drinking on 8-OHdG ( ptrend < 0.001 and 0.034, respectively). Multivariate logistic regression analysis revealed that high levels of urinary 1-hydroxypyrene were associated with a significantly increased risk of S phase arrest (odds ratio (OR) = 1.32, p = 0.03), so as heavy alcohol drinking (OR = 1.31, p = 0.02). Drinking can significantly modify the effects of urinary 1-hydroxypyrene on S phase arrest, during co-exposure to both heavy drinking and median or high 1-hydroxypyrene levels (OR = 3.31, 95% confidence interval (CI) = 1.21–7.63 and OR = 2.56, 95% CI = 1.08–6.06, respectively). Our findings demonstrate that coke oven workers with heavy drinking will cause S phase arrest so as to repair more serious DNA damage.

Essential Metals Zinc, Selenium, and Strontium Protect against Chromosome Damage Caused by Polycyclic Aromatic Hydrocarbons Exposure

Essential metals play important roles in maintaining cellular homeostasis, but the effects of their interaction with the environmental pollutants are still not very well-known in human subjects. The aim of this study was to evaluate the roles of essential metals and their interactions with polycyclic aromatic hydrocarbons (PAHs) on chromosome damage, an early carcinogenic event. A total of 1245 male workers were included in this study and the levels of 11 urinary essential metals, 12 urinary PAH metabolites, plasma concentrations of benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, and lymphocyte micronucleus (MN) frequencies were monitored. We found that zinc (Zn), selenium (Se), and strontium (Sr) have significant inverse dose-response relationships with MN frequencies (all P < 0.05). Furthermore, the protective roles of Zn, Se, and Sr were mainly shown among subjects with high levels of BPDE-Alb adducts. Significant effect modification of BPDE-Alb adducts on the associations of Zn, Se, and Sr with MN frequencies was observed (all Pinteraction < 0.05). Our study showed evidence that Zn, Se, and Sr play protective roles in reducing chromosome damage, and these effects can be modified by PAH exposure levels. These findings add potential evidence for the preventive effects of Zn, Se, and Sr against carcinogenesis in human subjects.

Lymphocyte oxidative stress/genotoxic effects are related to serum IgG and IgA levels in coke oven workers

We investigated oxidative stress/genotoxic effects levels, immunoglobulin levels, polycyclic aromatic hydrocarbons (PAHs) levels exposed in 126 coke oven workers and in 78 control subjects, and evaluated the association between oxidative stress/genotoxic effects levels and immunoglobulin levels. Significant differences were observed in biomarkers, including 1-hydroxypyrene levels, employment time, percentages of alcohol drinkers, MDA, 8-OHdG levels, CTL levels and CTM, MN, CA frequency, and IgG, IgA levels between the control and exposed groups. Slightly higher 1-OHP levels in smoking users were observed. For the dose-response relationship of IgG, IgA, IgM, and IgE by 1-OHP, each one percentage increase in urinary 1-OHP generates a 0.109%, 0.472%, 0.051%, and 0.067% decrease in control group and generates a 0.312%, 0.538%, 0.062%, and 0.071% decrease in exposed group, respectively. Except for age, alcohol and smoking status, IgM, and IgE, a significant correlation in urinary 1-OHP and other biomarkers in the total population was observed. Additionally, a significant negative correlation in genotoxic/oxidative damage biomarkers of MDA, 8-OH-dG, CTL levels, and immunoglobins of IgG and IgA levels, especially in coke oven workers, was found. These data suggest that oxidative stress/DNA damage induced by PAHs may play a role in toxic responses for PAHs in immunological functions.

Women are more susceptible than men to oxidative stress and chromosome damage caused by polycyclic aromatic hydrocarbons exposure

Exposure to environmental polycyclic aromatic hydrocarbons (PAHs) has been associated with increased risk of cancer, but evidence for gender differences in this association is limited. The aim of this study was to examine the gender differences in PAHs caused early genotoxic effects such as oxidative stress and chromosome damage, which are potential carcinogenic etiology of PAHs. A total of 478 nonsmoking workers (272 men and 206 women) from a coke oven plant were recruited. We determined 16 environmental PAHs in their workplaces, and measured concentrations of 12 urinary PAH metabolites (OH-PAHs), plasma benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, urinary 8-hydroxydeoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-iso-PGF2α), and micronucleus frequencies in lymphocytes in all subjects. It showed that, women working at the office, adjacent to the coke oven, and on the bottom or side of the coke oven displayed significantly higher levels of urinary 8-OHdG and 8-iso-PGF2α, and lymphocytic micronucleus frequencies compared with men working at above areas, respectively (all P < 0.05). These gender differences remain significant after adjusted for potential confounders and urinary ΣOH-PAHs or plasma BPDE-Alb adducts. A significant interaction existed between gender and BPDE-Alb adducts on increasing micronucleus frequencies (Pinteraction  < 0.001). We further stratified all workers by the tertiles of urinary ΣOH-PAHs or plasma BPDE-Alb adducts, and the above gender differences were more evident in the median- and high-exposure groups (all P < 0.05). In conclusion, women were more susceptible than men to oxidative stress and chromosome damage induced by PAHs, which may add potential evidence underlying gender differences in PAH exposure-related lung cacinogenesis.

Dose-response relationships of polycyclic aromatic hydrocarbons exposure and oxidative damage to DNA and lipid in coke oven workers

Polycyclic aromatic hydrocarbons (PAHs) are known to induce reactive oxygen species and oxidative stress, but the dose-response relationships between exposure to PAHs and oxidative stress levels have not been established. In this study, we recruited 1333 male coke oven workers, monitored the levels of environmental PAHs, and measured internal PAH exposure biomarkers including 12 urinary PAH metabolites and plasma benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, as well as the two oxidative biomarkers urinary 8-hydroxydeoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-iso-PGF2α). We found that the total concentration of urinary PAH metabolites and plasma BPDE-Alb adducts were both significantly associated with increased 8-OHdG and 8-iso-PGF2α in both smokers and nonsmokers (all p < 0.05). This exposure-response effect was also observed for most PAH metabolites (all p(trend) < 0.01), except for 4-hydroxyphenanthrene and 8-OHdG (p(trend) = 0.108). Furthermore, it was shown that only urinary 1-hydroxypyrene has a significant positive association with both 8-OHdG and 8-iso-PGF2α after a Bonferroni correction (p < 0.005). Our results indicated that urinary ΣOH-PAHs and plasma BPDE-Alb adducts can result in significant dose-related increases in oxidative damage to DNA and lipids. Furthermore, when a multianalyte method is unavailable, our findings demonstrate that urinary 1-hydroxypyrene is a useful biomarker for evaluating total PAHs exposure and assessing oxidative damage in coke oven workers.

A novel use of neural network model to determine the effects of multibiomarker on early health damage among Chinese steel workers

Coke-oven workers are exposed to many kinds of pollutants that can cause health damage even lead to carcinogenesis. Therefore, it is critical to identify biomarkers that predict early health damage in these exposed individuals in molecular epidemiological studies. We applied an artificial neural network (ANN) model to the identification of such predictors in a study of coke-oven workers. The study included 330 steel-factory workers who were exposed to different levels of polycyclic aromatic hydrocarbons (PAHs) in the workplace and their levels of early health damage were determined by cytokinesis-block micronuclei (CMN), heat shock protein 70 (Hsp70) expression, benzo(a)pyrene diolepoxide-albumin adduct (BPDE-AA), and olive tail moment (OTM). The ANN model was built to predict the early health damage index, and the receiver operating characteristic (ROC) curve was used to illustrate the judged criteria and the ANN model. Trend Chi-square modeling was also performed. We found that there were 55 subjects with early health damage among 330 workers based on the multibiomarker criteria using the 95 percentile of the control group as the cut-off value, while there were 22-35 positive subjects if screening by any single biomarker. The Cochran-Armitage trend test for these findings were statistically significant (Z = 3.21, P = 0.0013). Six variables were selected to simulate the ANN model. The area under ROC (AUROC) was 0.726 ± 0.037 (P < 0.001), and the predictors included workplace, cholesterol, waistline, and others. Therefore, collective using CMN frequency, Hsp70 level, BPDE-AA level, and OTM with equal weights to make an initial screening test for early health damage in coke-oven workers is feasible and superior to any single biomarker. The determinants of the effects of multibiomarker on early health damage screening can be identified by the ANN model and ROC curve method.

[Expression of PAH-DNA adducts in lung tissues of Xuanwei female lung cancer patients]

BACKGROUND AND OBJECTIVE

The coal-fired pollution in Xuanwei area has been considered to be local main reason for high incidence of female lung cancer. The aim of this study is to explore the expression of PAH-DNA adducts in lung tissues of Xuanwei female lung cancer patients and to explore the relationship between the large number of coal-fired pollution PAHs materials and the high incidence of Xuanwei female lung cancer.

METHODS

We totally collected each 20 cases of Xuanwei female lung cancer patients, Xuanwei male lung cancer patients, Non-Xuanwei female lung cancer patients and collect each 10 cases of Xuanwei, Non-Xuanwei female patients with benign lung lesions. The cancer tissues, adjacent cancer tissues and normal lung tissues were collected in lung cancer patients and only the normal tissues were collected in benign lung lesion patients. There were total 80 cases and 200 tissues. Immunofluorescence was used to detect the expression of PAH-DNA adducts in each group. Image pro-plus 6.0 software was used to analyze the images and part quantified analysis. SPSS 13.0 statistical software was used to analyze the data.

RESULTS

The positive expression of PAH-DNA adducts in lung cancer tissues, adjacent cancer tissues and normal lung tissues of Xuanwei female lung cancer patients were 90%, 80% and 65%. They were higher than the positive expression of PAH-DNA adducts in Xuanwei male lung cancer patients (35%, 30%, 30%) and Non-Xuanwei female lung cancer patients (20%, 15%, 10%) (P < 0.01). The expressions in lung tissues ofXuanwei female benign lung lesion patients (positive expression is 70%) were higher than it in Non-Xuanwei female benign lung lesion patients (positive expression is 10%). With the direction changing from cancer tissues, adjacent cancer tissues to normal lung tissues, the expressions of PAH-DNA adducts were decreased but had no statistical difference (P > 0.05S).

CONCLUSION

The expressions of PAH-DNA adducts in lung tissues of Xuanwei female were higher than which in Xuanwei male and Non-Xuanwei female.

Functional promoter -1271G>C variant of HSPB1 predicts lung cancer risk and survival

PURPOSE Heat-shock protein 27 (Hsp27), encoded by HSPB1, plays crucial roles in tumorigenesis and cell survival and is reported to be an independent prognosis marker for cancer. We hypothesized that genetic variants of the HSPB1 gene may be associated with lung cancer susceptibility and survival. PATIENTS AND METHODS We first resequenced the full-length HSPB1 gene and then genotyped three selected tag single nucleotide polymorphisms (SNPs) in 1,152 paired Chinese lung cancer patient cases and controls. Another 500 paired patient cases and controls were used for replication. We also evaluated the roles of these tagSNPs in the overall survival of 248 patients with advanced non-small-cell lung cancer (NSCLC), and validated the results in another 335 patients with advanced NSCLC. The genotype-phenotype correlation was assessed in 309 workers with occupational exposure to polycyclic-aromatic hydrocarbons (PAHs) as well as by luciferase reporter assay and Western blotting analysis. RESULTS The -1271C allele was associated with a significantly increased lung cancer risk in the two independent patient case-control studies (P < .05 for both), but it conferred a favorable survival for patients with advanced NSCLC in two independent cohorts (adjusted hazard ratio, 0.66 and 0.75, respectively). The occupational PAH-exposed workers carrying the -1271C allele showed higher DNA damage levels than those with the -1271G allele (P = .027). Furthermore, the -1271C allele significantly decreased luciferase activity in four cell lines and resulted in lower Hsp27 expression levels in normal lung tissues when compared with -1271G allele (P < .05). CONCLUSION The functional HSPB1 promoter -1271G>C variant may affect lung cancer susceptibility and survival by modulating endogenous Hsp27 synthesis levels.

Genetic variants of nucleotide excision repair genes are associated with DNA damage in coke oven workers

We explored the effects of single nucleotide polymorphisms (SNP) of nucleotide excision repair (NER) genes on DNA damage caused by exposure to carcinogenic polycyclic aromatic hydrocarbons (PAH) in 475 Chinese workers. We quantified urinary 1-hydroxypyrene using high-performance liquid chromatography, and the DNA damage level of lymphocytes was examined by the comet assay and represented as the Olive tail moment (OTM) value. We genotyped 38 tagSNPs in 10 NER genes. The SNP function was further investigated using luciferase reporter assay in three cell lines. Our results showed that two promoter SNPs, XPA rs1800975 and XPC rs3731055, were associated with lower OTM values (P(trend) = 0.01 and 0.02 respectively). However, another missense SNP rs2228001 in the XPC gene was positively associated with OTM value (P(trend) = 0.01). A stratified analysis found that the association between this SNP and DNA damage was only observed among subjects with higher PAH exposure levels but not among those with lower exposure levels (P(interaction) = 0.018). A dose-response association was found between the combined risk alleles of the above three genetic variants and increased DNA damage levels (P(trend) = 0.004). This association was more pronounced in subjects with higher PAH exposure than those with lower exposure levels (P(interaction) = 0.046). Our functional study indicated that XPA rs1800975G and XPC rs3731055A alleles had a higher luciferase expression than their corresponding SNP alleles (P < 0.05). These results suggested that genetic variations in key NER genes, especially in XPA and XPC genes, may modulate DNA damage levels when exposed to PAHs.

Comet assay: a reliable tool for the assessment of DNA damage in different models

New chemicals are being added each year to the existing burden of toxic substances in the environment. This has led to increased pollution of ecosystems as well as deterioration of the air, water, and soil quality. Excessive agricultural and industrial activities adversely affect biodiversity, threatening the survival of species in a particular habitat as well as posing disease risks to humans. Some of the chemicals, e.g., pesticides and heavy metals, may be genotoxic to the sentinel species and/or to non-target species, causing deleterious effects in somatic or germ cells. Test systems which help in hazard prediction and risk assessment are important to assess the genotoxic potential of chemicals before their release into the environment or commercial use as well as DNA damage in flora and fauna affected by contaminated/polluted habitats. The Comet assay has been widely accepted as a simple, sensitive, and rapid tool for assessing DNA damage and repair in individual eukaryotic as well as some prokaryotic cells, and has increasingly found application in diverse fields ranging from genetic toxicology to human epidemiology. This review is an attempt to comprehensively encase the use of Comet assay in different models from bacteria to man, employing diverse cell types to assess the DNA-damaging potential of chemicals and/or environmental conditions. Sentinel species are the first to be affected by adverse changes in their environment. Determination of DNA damage using the Comet assay in these indicator organisms would thus provide information about the genotoxic potential of their habitat at an early stage. This would allow for intervention strategies to be implemented for prevention or reduction of deleterious health effects in the sentinel species as well as in humans.

DNA adduct formation among workers in a Thai industrial estate and nearby residents

The genotoxic effects of air pollutant exposures have been studied in people living and working in Map Ta Phut, Rayong province, Thailand, a site where is located the Map Ta Phut Industrial Estate (MIE) one of the largest steel, refinery and petrochemical complex in the South-Eastern Asia. This was done by the conduction of a transversal study aimed to compare the prevalence of bulky DNA adducts in groups of subjects experiencing various degree of air pollution. DNA adduct analysis was performed in the leukocytes of 201 volunteers by the (32)P-postlabelling assay: 79 were workers in the MIE complex, including 24 refinery workers, 40 steel workers and 15 tinplate workers, 72 were people residing downwind in the MIE area and 50 were residents in a control district of the same Rayong province but without industrial exposures. The groups of workers were analyzed separately to evaluate if DNA adduct formation differs by the type of industry. The levels of bulky DNA adducts were 1.17+/-0.17 (SE) adducts/10(8) nucleotides in refinery workers, 1.19+/-0.19 (SE) in steel workers, 0.87+/-0.17 (SE) in tinplate workers, 0.85+/-0.07 (SE) in MIE residents and 0.53+/-0.05 (SE) in district controls. No effects of smoking habits on DNA adducts was found. The multivariate regression analysis shows that the levels of DNA adducts were significantly increased among the individuals living near the MIE industrial complex in respect to those resident in a control district (p<0.05). In the groups of occupationally exposed workers, the highest levels of DNA adducts were found among the workers experiencing an occupational exposure to polycyclic aromatic hydrocarbons, e.g. the steel factory and refinery workers. When we have evaluated if the levels of DNA adducts of the PAH exposed workers were different from those of the MIE residents, a statistical significantly difference was found (p<0.05). Our present study indicates that people living near point sources of industrial air pollution can experiment an excess of DNA adduct formation. The emissions from the MIE complex are the main source of air pollution in this area and can be the cause of such increment in the levels of DNA damage.