Smoking modify the effects of polycyclic aromatic hydrocarbons exposure on oxidative damage to DNA in coke oven workers

Association between plasma CC16 levels and lung function changes in coke oven workers: A cohort study from 2014 to 2023

Club cell secretory protein (CC16) is considered a biological marker indicating lung epithelial and lung permeability. The joint effect of polycyclic aromatic hydrocarbons (PAHs) exposure on CC16 levels and the association between CC16 levels and long-term lung function changes lacks epidemiological evidence. To investigate the effect of PAHs exposure on plasma CC16 levels and the association between CC16 levels and long-term lung function changes, this study enrolled 307 coke oven workers in 2014, measured their baseline concentrations of urinary PAHs metabolites and plasma CC16, with follow-up after nine years. Bayesian kernel machine regression (BKMR) was employed to analyze the effect of mixed PAHs metabolites. The dose-effect association between baseline CC16 levels and lung function during 2014-2023 was explored using restricted cubic spline (RCS) models, and stratified analysis investigated the effect modification of PAHs exposure and smoking status on this association. The median age of the participants was 40 years, with 93.81 % male. The results showed that plasma CC16 levels decreased by 2.02 ng/mL (95 % CI: -3.77, -0.27) among all participants and FVC (% predicted) decreased by 2.87 % (95 % CI: -5.59, -0.14) in the low CC16 group with each unit increase in log-transformed 2-OHNAP. The BKMR model revealed a negative association between PAHs metabolites and both plasma CC16 levels and FVC (% predicted). Plasma CC16 decreased by 1.05 units when all PAHs metabolites at P65 compared to those at P50. After 9 years of follow-up, baseline CC16 levels were significantly associated with follow-up FVC (% predicted), FEV1 (% predicted), and small airway dysfunction risk. Furthermore, high PAHs exposure and smoking enhanced the association between CC16 and lung function. In conclusion, PAHs exposure decreases CC16 levels, and coking workers with low baseline CC16 levels may experience more severe future lung function decline.

A Systematic Review of Polycyclic Aromatic Hydrocarbon Derivatives: Occurrences, Levels, Biotransformation, Exposure Biomarkers, and Toxicity

Polycyclic aromatic hydrocarbon (PAH) derivatives constitute a significant class of emerging contaminants that have been ubiquitously detected in diverse environmental matrixes, with some even exhibiting higher toxicities than their corresponding parent PAHs. To date, compared with parent PAHs, fewer systematic summaries and reanalyses are available for PAH derivatives with great environmental concerns. This review summarizes the current knowledge on the chemical species, levels, biotransformation patterns, chemical analytical methods, internal exposure routes with representative biomarkers, and toxicity of PAH derivatives, primarily focusing on nitrated PAHs (NPAHs), oxygenated PAHs (OPAHs), halogenated PAHs (XPAHs), and alkylated PAHs (APAHs). A collection of 188 compounds from four categories, 44 NPAHs, 36 OPAHs, 56 APAHs, and 52 XPAHs, has been compiled from 114 studies that documented the environmental presence of PAH derivatives. These compounds exhibited weighted average air concentrations that varied from a lower limit of 0.019 pg/m3 to a higher threshold of 4060 pg/m3. Different analytical methods utilizing comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC × GC-TOF-MS), gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF-MS), comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC × GC-QQQ-MS), and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), that adopted untargeted strategies for the identification of PAH derivatives are also reviewed here. Additionally, an in-depth analysis of biotransformation patterns for each category is provided, including the likelihood of specific biotransformation reaction types. For the toxicity, we primarily summarized key metabolic activation pathways, which could result in the formation of reactive metabolites capable of covalently bonding with DNA and tissue proteins, and potential health outcomes such as carcinogenicity and genotoxicity, oxidative stress, inflammation and immunotoxicity, and developmental toxicity that might be mediated by the aryl hydrocarbon receptor (AhR). Finally, we pinpoint research challenges and emphasize the need for further studies on identifying PAH derivatives, tracking external exposure levels, evaluating internal exposure levels and associated toxicity, clarifying exposure routes, and considering mixture exposure effects. This review aims to provide a broad understanding of PAH derivatives' identification, environmental occurrence, human exposure, biotransformation, and toxicity, offering a valuable reference for guiding future research in this underexplored area.

Effects of H19/SAHH/DNMT1 on the oxidative DNA damage related to benzo[a]pyrene exposure

The mechanisms that long noncoding RNA (lncRNA) H19 binding to S-adenosylhomocysteine hydrolase (SAHH) interacted with DNA methyltransferase 1 (DNMT1) and then regulated DNA damage caused by polycyclic aromatic hydrocarbons (PAHs) remain unclear. A total of 146 occupational workers in a Chinese coke-oven plant in 2014 were included in the final analyses. We used high-performance liquid chromatography mass spectrometry (HPLC-MS) equipped to detect urine biomarkers of PAHs exposure, including 2-hydroxynaphthalene (2-NAP), 2-hydroxyfluorene (2-FLU), 9-hydroxyphenanthrene (9-PHE) and 1-hydroxypyrene (1-OHP). The levels of SAM and SAH in plasma were detected by HPLC-ultraviolet. By constructing various BEAS-2B cell models exposed to 16 μM benzo[a]pyrene (BaP) for 24 h, toxicological parameters reflecting distinct mechanisms were evaluated. We documented that urinary 1-hydroxypyrene (1-OHP) levels were positively associated with blood H19 RNA expression (OR: 1.51, 95% CI: 1.03-2.19), but opposite to plasma SAHH activity (OR: 0.63, 95% CI: 0.41-0.98) in coke oven workers. Moreover, by constructing various BEAS-2B cell models exposed to benzo[a]pyrene (BaP), we investigated that H19 binding to SAHH exaggerated DNMT1 expressions and activity. Suppression of H19 enhanced the interaction of SAHH and DNMT1 in BaP-treated cells, decreased eight-oxoguanine DNA glycosylase 1 (OGG1) methylation, reduced oxidative DNA damage and lessened S phase arrest. However, SAHH or DNMT1 single knockdown and SAHH/DNMT1 double knockdown showed the opposite trend. A H19/SAHH/DNMT1 axis was involved in OGG1 methylation, oxidative DNA damage and cell cycle arrest by carcinogen BaP.

Oxygenated and Nitrated Polycyclic Aromatic Hydrocarbons: Sources, Quantification, Incidence, Toxicity, and Fate in Soil—A Review Study

The genotoxicity, mutagenesis, and carcinogenic effects of polycyclic aromatic hydrocarbon (PAH) derivatives may exceed the parent PAHs. However, their influence on the soil environment has not been explored to a large extent. Oxygenated polycyclic aromatic hydrocarbons (OPAHs) and nitrated polycyclic aromatic hydrocarbons (NPAHs) are typical polar substituted compounds. We offer a review of the literature on the sources, quantification, incidence, toxicity, and transport of these compounds in soil. Although their environmental concentrations are lower than those of their parent compounds, they exert higher toxicity. Both types of substances are basically related to carcinogenesis. OPAHs are not enzymatically activated and can generate reactive oxygen species in biological cells, while NPAHs have been shown to be mutagenic, genotoxic, and cytotoxic. These compounds are largely derived from the transformation of PAHs, but they behave differently in soil because of their higher molecular weight and dissimilar adsorption mechanisms. Therefore, specialized knowledge of model derivatives is required. We also made recommendations for future directions based on existing research. It is expected that the review will trigger scientific discussions and provide a research basis for further study on PAH derivatives in the soil environment.

Exposure to polycyclic aromatic hydrocarbons and the associations with oxidative stress in waste incineration plant workers from South China

Waste incineration is one of the most common emission sources of polycyclic aromatic hydrocarbons (PAHs), causing potential occupational exposure in waste incineration workers. However, relative investigations among waste incineration plant workers are still very limited, particularly in China. Therefore, we collected urine specimens from 77 workers in a waste incineration plant as the exposed group, and 101 residents as the control group in Shenzhen, China. Nine mono-hydroxylated PAH metabolites (OH-PAHs) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured, and their internal relationships were explored. The urinary levels of most OH-PAHs and 8-OHdG in the exposed group exhibited high levels versus another group (p < 0.05). We found negative associations between OH-PAHs and 8-OHdG in the control group (p < 0.05), while most of OH-PAHs were not associated with 8-OHdG in the exposed group, which indicated that the exposure to waste incineration could enlarge the level of individual oxidative stress damage. Nevertheless, PAHs were less likely to trigger obvious health risks in exposed workers through estimation of human intake and exposure risks. This study provides a reference for occupational PAH exposure and strengthen the need of health monitoring among incineration workers.

Polycyclic aromatic hydrocarbons, long non-coding RNA expression, and DNA damage in coke oven workers

Exposure to polycyclic aromatic hydrocarbons (PAHs) was associated with DNA damage, while the roles of long non-coding RNAs (lncRNAs) in the associations were unclear. We aimed to assess the association of lncRNA NR_024564 with urinary monohydroxy PAHs (OH-PAHs) and DNA damage among 332 coke oven workers. We determined 12 OH-PAHs by gas chromatography-mass spectrometry, and the expression level of NR_024564 by droplet digital RT-PCR and DNA damage by the comet assay. In total participants, we found that NR_024564 was not significantly associated with OH-PAHs or comet parameters. However, among workers with ≥ 20 working years, multiple OH-PAHs including urinary 1-hydroxyphenanthrene (1-OHPh), 2-OHPh, 3-OHPh, 9-OHPh, 1‑hydroxypyrene, and total PAH metabolites were related to increased comet parameters. Moreover, NR_024564 was significantly associated with 2-OHPh and four comet parameters. Each 1% increase in 2-OHPh was associated with 0.35% reduction (95% CI: 0.16%, 0.55%) in NR_024564 (P-_FDR = 0.005), and 2-OHPh was marginally interacted with working years in relation to NR_024564 decrease. Also, each 1% increment of NR_024564 was related to 0.04-0.13% decrease of Olive tail moment, percent DNA in the comet tail, tail length, and tail moment (all P-_FDR < 0.05). Furthermore, low NR_024564 level combined with high levels of 1-OHPh and 2-OHPh or ≥ 20 working years was positively associated with the comet parameters among the total participants. Our results indicated that NR_024564 might be linked to the adverse associations of PAHs with the DNA damage of coke oven workers who worked for ≥ 20 years.

Development of a highly efficient in-tube solid-phase microextraction system coupled with UHPLC-MS/MS for analyzing trace hydroxyl polycyclic aromatic hydrocarbons in biological samples

Hydroxyl polycyclic aromatic hydrocarbons are considered active mutagenic and carcinogenic substances and are found in extremely low levels (ng/g) in biological samples. As a result, their determination in urine and blood samples is challenging, and a sensitive and effective method for the analysis of trace hydroxyl polycyclic aromatic hydrocarbons in complex biological matrices is required. In this work, a novel macroporous in-tube solid-phase microextraction monolith was prepared via a thiol-yne click reaction, and a highly efficient analytical method based on in-tube solid-phase microextraction coupled with UHPLC-MS/MS was developed to determine hydroxyl polycyclic aromatic hydrocarbons with low detection limits of 0.137-11.0 ng/L in complex biological samples. Four hydroxyl polycyclic aromatic hydrocarbons, namely, 2-hydroxyanthraquinone, 1-hydroxypyrene, 1,8-dihydroxyanthraquinone, and 6-hydroxychrysene, were determined in the urine samples of smokers, non-smokers, and whole blood samples of mice. Satisfactory recoveries were achieved in the range of 83.1-113% with relative standard deviations of 3.2-9.7%. It was found that implementation of the macroporous monolith gave a highly efficient approach for enriching trace hydroxyl polycyclic aromatic hydrocarbons in biological samples.

Health damage to housewives by contaminants emitted from coal combustion in the Chinese countryside: focusing on day-to-day cooking

PURPOSE

The study aimed to estimate the health damage and find out the main exposure pathways of housewives posed by polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) from coal combustion in rural areas of China.

METHODS

We obtained the concentrations of 16 PAHs and 8 HMs from published literatures and the Monte Carlo simulation was used to process and analysis the data. Sensitivity analysis was also applied to clear parameter uncertainty and the health damage of housewives was quantitatively evaluated by loss of life expectancy.

RESULTS

Housewives' carcinogenic risks from PAHs exposure were in descending order of inhalation > ingestion > dermal contact, while exposed to HMs were ingestion > dermal contact > inhalation. The carcinogenic risks from PAHs primarily originated from benzo[a]pyrene (BaP), dibenz[ah]anthracene (DahA) and benzo[b]fluorathene (BbF). For HMs, arsenic posed the highest carcinogenic risk to housewives, with a contribution of 92.98%. In addition, the life expectancy loss of housewives exposed to PAHs was 469.04 min from inhalation and 51.82 min for HMs from ingestion.

CONCLUSION

Through a comprehensive assessment of the health risks in housewives exposed to emissions from coal combustion, we can gain insight into the hazards from PAHs and HMs in housewives, and take measures to reduce their exposure risks.

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.

A novel switchable solvent liquid-phase microextraction technique based on the solidification of floating organic droplets: HPLC-FLD analysis of polycyclic aromatic hydrocarbon monohydroxy metabolites in urine samples

A novel switchable solvent liquid-phase microextraction technique, based on the solidification of floating organic droplets (SS-LPME-SFO), was developed for the pretreatment of aqueous samples.

CYP1A1 methylation mediates the effect of smoking and occupational polycyclic aromatic hydrocarbons co-exposure on oxidative DNA damage among Chinese coke-oven workers

BACKGROUND

Multiple factors, including co-exposure between lifestyle and environmental risks, are important in susceptibility to oxidative DNA damage. However, the underlying mechanism is not fully understood. This study was undertaken to evaluate whether Cytochrome P4501A1 (CYP1A1) methylation can mediate the co-exposure effect between smoking and occupational polycyclic aromatic hydrocarbons (PAH) in development of oxidative DNA damage.

METHODS

We explored the associations between smoking and occupational PAH co-exposure effect, CYP1A1 methylation and oxidative DNA damage among 500 workers from a coke-oven plant in China. Urine biomarkers of PAH exposure (1-hydroxypyrene, 1-OHP; 2-hydroxynaphthalene, 2-NAP; 2-hydroxyfluorene, 2-FLU; and 9-hydroxyphenanthren, 9-PHE) and a marker of oxidative DNA damage (8-hydroxy- 2'- deoxyguanosine, 8-OHdG) were measured by high performance liquid chromatography. CYP1A1 methylation was measured by pyrosequencing. Finally, mediation analysis was performed to investigate whether CYP1A1 methylation mediated smoking and occupational PAH co-exposure effect on oxidative DNA damage.

RESULTS

We observed significant associations of smoking and 1-OHP co-exposure with CYP1A1 hypomethylation (OR: 1.87, 95% CI: 1.01-3.47) and high 8-OHdG (OR: 2.13, 95% CI: 1.14-3.97). There was a significant relationship between CYP1A1 hypomethylation and high 8-OHdG (1st vs. 3rd tertile = 1.58, 95% CI: 1.01-2.47, P for trend = 0.046). In addition, mediation analysis suggested CYP1A1 hypomethylation could explain 13.6% of effect of high 8-OHdG related to smoking and 1-OHP co-exposure.

CONCLUSIONS

Our findings suggested that the co-exposure effect of smoking and occupational PAH could increase the risk of oxidative DNA damage by a mechanism partly involving CYP1A1 hypomethylation.

Determination of 3-Hydroxybenzo[a]pyrene Glucuronide/Sulfate Conjugates in Human Urine and Their Association with 8-Hydroxydeoxyguanosine

While 3-hydroxybenzo[a]pyrene (3-OHBaP) is a preferable biomarker to assess human exposure to benzo[a]pyrene (BaP), a sensitive and simple method is lacking. In this study, a specific and sensitive method based on liquid chromatography coupled with electrospray tandem mass spectrometry (LC-ESI-MS/MS) was developed for direct analysis of 3-OHBaP glucuronide and sulfate conjugates in human urine samples without enzymatic hydrolysis. The limits of detection (LODs) were 0.06 ng L^-1 for BaP-3-sulfate (BaP-3-S) and 0.16 ng L^-1 for BaP-3-glucuronide (BaP-3-G), which showed high sensitivity. Both compounds showed excellent linearity (r² > 0.99) in the range of 0.01-10 μg L^-1 in the instrumental calibration. The absolute recoveries of the target analytes spiked in human urine for the entire analytical procedure were 68.3 ± 4.96% (mean ± SD) and 63.7 ± 5.47% for BaP-3-S and BaP-3-G, respectively. This method was applied to quantify BaP-3-G and BaP-3-S in 150 urine samples collected from healthy volunteers. The mean concentration of BaP-3-S was 0.67 ng g^-1 creatinine (<LOD to 10.20 ng g^-1 creatinine), about 10-fold lower than that of BaP-3-G (6.73 ng g^-1 creatinine, < LOD to 52.64 ng g^-1 creatinine). For comparison, we also detected the concentration of free 3-OHBaP in 15 randomly selected samples without enzymatic hydrolysis and found at least >98% of 3-OHBaP is excreted mainly in these two conjugated forms in human urine. A statistically significant positive association was observed between urinary 3-OHBaP conjugates and urinary 8-OHdG levels (p < 0.001) in the general population. This study developed a sensitive and simple method to determine urinary glucuronide/sulfate conjugated BaP metabolites and for the first time found that BaP exposure associated with 8-OHdG levels in the general population.

OGG1 methylation mediated the effects of cell cycle and oxidative DNA damage related to PAHs exposure in Chinese coke oven workers

Previous publications have indicated that polycyclic aromatic hydrocarbons (PAHs) exposures are associated with increased DNA damage and abnormal cell cycle arrest; however, the details of mechanisms remain largely unknown. This study aimed to quantify the associations of 8-oxoguanine DNA glycosylase (OGG1) methylation with urinary PAHs metabolites, DNA damage and cell cycle arrest, and further to assess the role of OGG1 methylation in mediating the association of urinary PAHs metabolites with DNA damage and cell cycle arrest. Urinary biomarkers of PAHs exposure and a marker of oxidative DNA damage (8-hydroxy-2'-deoxyguanosin, 8-OHdG) were measured by high performance liquid chromatography. Cell cycle of lymphocyte was analysed with flow cytometry and OGG1 methylation in venous blood was measured by pyrosequencing. After adjusting for covariates, urinary 1-OHP levels were positively associated with lymphocyte S phase arrest and oxidative DNA damage, while were negatively associated with G0/G1 phase arrest. OGG1 methylation was not only positively correlated with urinary 1-OHP in a dose-responsive manner (P trend = 0.008) but was also associated with G0/G1 phase arrest (OR: 0.63, 95% CI: 0.41-0.97), S phase arrest (OR: 1.55, 95% CI: 1.01-2.40) and oxidative DNA damage (OR: 1.71, 95% CI: 1.02-2.86). Mediation analysis estimated that OGG1 methylation mediated about 20% of associations between urinary 1-OHP levels and cell cycle arrest and oxidative DNA damage, respectively (all P < 0.05). Our findings suggested that urinary 1-OHP concentrations were associated with cell cycle arrest and oxidative DNA damage by a mechanism partly involving OGG1 methylation.

A novel aptamer-based online magnetic solid phase extraction method for simultaneous determination of urinary 8-hydroxy-2'-deoxyguanosine and monohydroxylated polycyclic aromatic hydrocarbons

In this work, an innovative aptamer-based magnetic adsorbent (Fe₃O₄@PDA-aptamer MNPs) was prepared by hydrothermal synthesis method followed by the surface functionalization of nanoparticles. After fixing in a steel stainless tube as sorbent of magnetic solid phase extraction (MSPE), an online magnetic solid phase extraction-high performance liquid chromatography-mass spectrometry (online-MSPE-HPLC-MS) method was developed and applied for the determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) simultaneously in urine. The synthesized sorbent presented outstanding features, including large specific surface area, high enrichment capacity and excellent stability. High throughput analysis can be achieved by affinity-specific adsorption of 8-OHdG and non-specific adsorption of OH-PAHs at the same time. In addition, online MSPE can greatly simplify the analysis process, reduce human errors and enhance the sensitivity. When compared with offline MSPE, a sensitivity enhancement of 30-400 times was obtained for the online method. Some experimental parameters such as the amount of the sorbent, sampling flow rate and sample volume, were optimized systematically. Under the optimal conditions, the limits of detection (LOD) were in the range of 0.028-0.114 ng mL^-1, and the correlation coefficients (R²) were higher than 0.9962. The relative standard deviations (RSDs) were less than 16.1% (n = 5) and the recoveries ranged from 71% to 116%. The above results show that the rapid, sensitive and automated online-MSPE-HPLC-MS method has potential application in the simultaneous determination of 8-OHdG and PAHs in complex sample matrix to assess the environmental exposure level.

Beyond the obvious: Environmental health implications of polar polycyclic aromatic hydrocarbons

The genotoxic, mutagenic and carcinogenic effects of polar polycyclic aromatic hydrocarbons (polar PAHs) are believed to surpass those of their parent PAHs; however, their environmental and human health implications have been largely unexplored. Oxygenated PAHs (oxy-PAHs) is a critical class of polar PAHs associated with carcinogenic effects without enzymatic activation. They also cause an upsurge in reactive oxygen species (ROS) in living cells. This results in oxidative stress and other consequences, such as abnormal gene expressions, altered protein activities, mutagenesis, and carcinogenesis. Similarly, some nitrated PAHs (N-PAHs) are probable human carcinogens as classified by the International Agency for Research on Cancer (IARC). Heterocyclic PAHs (polar PAHs containing nitrogen, sulphur and oxygen atoms within the aromatic rings) have been shown to be potent endocrine disruptors, primarily through their estrogenic activities. Despite the high toxicity and enhanced environmental mobility of many polar PAHs, they have attracted only a little attention in risk assessment of contaminated sites. This may lead to underestimation of potential risks, and remediation end points. In this review, the toxicity of polar PAHs and their associated mechanisms of action, including their role in mutagenic, carcinogenic, developmental and teratogenic effects are critically discussed. This review suggests that polar PAHs could have serious toxicological effects on human health and should be considered during risk assessment of PAH-contaminated sites. The implications of not doing so were argued and critical knowledge gaps and future research requirements discussed.

Maternal urinary 2-hydroxynaphthalene and birth outcomes in Taiyuan, China

BACKGROUND

Naphthalene is the simplest polycyclic aromatic hydrocarbon (PAH). It is easily emitted into the atmosphere, posing a significant risk to human health. However, limited studies have described the impact of naphthalene exposure on birth outcomes. In this study, we investigated the association between the maternal urinary metabolites of naphthalene, 2-hydroxynaphthalene (2-OH NAP), and birth outcomes.

METHOD

In the present study, four urinary PAH metabolites were measured in 263 pregnant women during late pregnancy. Multiple linear regression analysis was used to analyze the relationship between the concentrations of 2-OH NAP and birth outcomes, and restricted cubic spline models were further used to examine the shapes of the dose-response association.

RESULT

General linear models showed that prenatal urinary 2-OH NAP was associated with lower birth weight (BW) (- 4.38% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.049) and higher cephalization index (CI) (4.30% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.038). These associations were linear and significant when 2-OH NAP was modeled as a continuous variable in restricted cubic spline models (P _linear = 0.0293 for 2-OH NAP and BW; P _linear = 0.0326 for 2-OH NAP and CI). Multiple linear regression data indicated that each 1 ln-unit increase in 2-OH NAP was significantly associated with a 2.09 g/cm increase in the CI. The associations among 2-OH NAP, BW, and CI were also observed in a subset of participants residing close to arterial traffic.

CONCLUSION

Our data indicated that prenatal exposure to naphthalene had an adverse effect on fetal birth outcomes, especially the brain development index. Reduced exposure to naphthalene may improve newborn health outcomes. In Taiyuan, naphthalene may result from traffic pollution.

Urinary 1-hydroxypyrene and smoking are determinants of LINE-1 and AhRR promoter methylation in coke oven workers

Coke oven emissions (COE) containing polycyclic aromatic hydrocarbons (PAHs) are predominant toxic constituents of particulate air pollution that have been linked to increased risk of lung cancer. Aberrant DNA methylation is one of the best known epigenetic changes in human cancers and healthy subjects exposed to carcinogens. The purpose of this study is to explore the factors influencing the methylation of long interspersed nuclear element-1 (LINE-1) and aryl-hydrocarbon receptor repressor (AhRR) in coke oven workers. The study population is composed by coke oven workers (348) and water treatment workers (131). And their urinary PAH metabolites were analyzed by high performance liquid chromatography; DNA methylation were measured by pyrosequencing. The urinary PAHs metabolites were significantly elevated in coke oven workers (P < 0.01). The results from multivariate logistic regression analysis showed that a high level of urinary 1-hydroxypyrene was associated with a significantly increased risk of hypomethylation of LINE-1 (OR: 1.80; 95% CI: 1.25, 2.60), and heavy smoking was associated with a significantly increased risk of hypomethylation of AhRR (OR: 1.44; 95% CI: 1.04, 2.00). Our findings demonstrate that urinary 1-hydroxypyrene may be a useful biomarker for evaluating the role of PAHs exposure on hypomethylation of LINE-1 among coke oven workers and that smoking may be an important factor affecting hypomethylation of AhRR.

DNA damage levels in electronics workers in Southern China: A micro-whole blood comet assay

We evaluated DNA damage levels of different categories of workers exposed to hazards inside electronics factories in Southern China. To find out the most dangerous risk factor, a cross-sectional study was conducted on a total of 584 exposed subjects and 138 controls in an electronics factory in Southern China, where the electronics industry is prevalent. The exposed hazards included isopropanol (IPO), lead, noise, video display terminals (VDT), lead in a high-temperature (high-temp) environment, and IPO in a high-temp environment. DNA damage detection was performed by the micro-whole blood comet assay using peripheral blood. DNA damage levels were estimated by percent tail DNA (%T). Linear regression models were used to test DNA damage differences between exposed groups and control group with adjustments for potential confounding factors. The level of DNA damage was more significant in both lead in a high-temp and IPO in a high-temp environment groups than in that of the controls (p<0.05). The differences remained significant after stratifying by smoking status (p<0.05). There were no significant differences between groups exposed to IPO, lead, noise, VDT environment and controls. In conclusion, we identified potential risk factors for DNA damage to electronics workers. Special attention should be paid to workers exposed to IPO and lead in a high-temp environment.