Effects of Polycyclic Aromatic Hydrocarbon Exposure and Telomere Length and their Interaction on Blood Lipids in Coal Miners.

OBJECTIVE: This study aimed to investigate the effects of polycyclic aromatic hydrocarbon (PAH) exposure and telomere length on lipids in coal miners. METHODS: Basic personal information of 637 coal miners was collected by questionnaire survey. Logistic regression, the Bayesian kernel machine regression model, and weighted quantile sum regression were used to analyze the effects of PAH metabolites and telomere length and their interactions on blood lipids. RESULTS: High exposure to 9-hydroxyphenanthrene (OR = 1.586, 95% CI: 1.011-2.487) and telomere shortening (OR = 1.413, 95% CI: 1.005-1.985) were associated with dyslipidemia. Weighted quantile sum results showed that 9-hydroxyphenanthrene accounted for the largest proportion of dyslipidemia (weight = 0.66). The interaction results showed that high 9-hydroxyphenanthrene exposure and short telomeres were risk factors for dyslipidemia in coal miners (OR = 2.085, 95% CI: 1.121-3.879). Conclusions: Our findings suggest that 9-hydroxyphenanthrene and shorter telomeres are risk factors for dyslipidemia, and their interaction increases the risk of dyslipidemia.

Evaluation of Models for Estimating Hydraulic Conductivity in Glacial Aquifers with NMR Logging.

Nuclear magnetic resonance (NMR) logging is a promising method for estimating hydraulic conductivity (K). During the past ∼60 years, NMR logging has been used for petroleum applications, and different models have been developed for deriving estimates of permeability. These models involve calibration parameters whose values were determined through decades of research on sandstones and carbonates. We assessed the use of five models to derive estimates of K in glacial aquifers from NMR logging data acquired in two wells at each of two field sites in central Wisconsin, USA. Measurements of K, obtained with a direct push permeameter (DPP), KDPP , were used to obtain the calibration parameters in the Schlumberger-Doll Research, Seevers, Timur-Coates, Kozeny-Godefroy, and sum-of-echoes (SOE) models so as to predict K from the NMR data; and were also used to assess the ability of the models to predict KDPP . We obtained four well-scale calibration parameter values for each model using the NMR and DPP measurements in each well; and one study-scale parameter value for each model by using all data. The SOE model achieved an agreement with KDPP that matched or exceeded that of the other models. The Timur-Coates estimates of K were found to be substantially different from KDPP . Although the well-scale parameter values for the Schlumberger-Doll, Seevers, and SOE models were found to vary by less than a factor of 2, more research is needed to confirm their general applicability so that site-specific calibration is not required to obtain accurate estimates of K from NMR logging data.

Focusing on testosterone levels in male: A half-longitudinal study of polycyclic aromatic hydrocarbon exposure and diastolic blood pressure in coke oven workers.

Polycyclic aromatic hydrocarbons (PAHs) can interfere with testosterone levels, and low levels of testosterone are associated with increased cardiovascular events. To explore the role of testosterone in PAHs exposure and cardiovascular health, we used data from the 2011-2016 National Health and Nutrition Examination Survey (NHANES) and a longitudinal database of 332 male coke oven workers from China. The urine PAHs, tobacco metabolites and plasma testosterone levels of coke oven workers were measured. There were inverse associations between serum (plasma) testosterone concentrations and the risk of dysarteriotony and dyslipidemia among the NHANES participants and coke oven workers. The results of the cross-lagged panel analysis among workers showed that the decrease in testosterone preceded the increase in diastolic blood pressure (DBP), and the absolute value of the path coefficient from baseline testosterone to follow-up DBP (ß2 = -8.162, P = 0.077) was significantly larger than the absolute value of the path coefficient from baseline DBP to follow-up testosterone (ß1 = -0.001, P = 0.781). Results from the half-longitudinal mediation analysis showed that baseline hydroxyfluorene predicted significant decreases in plasma testosterone from baseline to follow-up (path a: 0.71, 95% CI: 1.26, -0.16), whereas plasma testosterone at baseline also predicted significant increments in DBP from baseline to follow-up (path b: 9.22, 95% CI: 17.24, -1.19). The indirect effect of PAHs on DBP via plasma testosterone level was marginally significant (test for indirect effects a*b (P = 0.08)). In conclusion, testosterone level is a longitudinal precursor to increased DBP and plays an essential role in the association between PAHs exposure and damage to the cardiovascular system. Coke oven workers with low plasma testosterone levels are more likely to experience adverse changes in blood pressure and lipid levels after exposure to PAHs.

Polycyclic aromatic hydrocarbons exposure was associated with microRNA differential expression and neurotransmitter changes: a cross-sectional study in coal miners.

Exposure to polycyclic aromatic hydrocarbons (PAHs) may cause neurobehavioral changes. This study aimed to explore the underlying mechanism of PAH neurotoxicity in coal miners. Urinary PAH metabolites, neurotransmitters, and oxidative stress biomarkers of 652 coal miners were examined. Subjects were divided into high and low-exposure groups based on the median of total urinary PAH metabolites. Differentially expressed miRNAs were screened from 5 samples in the low-exposure group (≤ 4.88 µmol/mol Cr) and 5 samples in the high-exposure group (> 4.88 µmol/mol Cr) using microarray technology, followed by bioinformatics analysis of the potential molecular functions of miRNA target genes. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was used to validate differentially expressed miRNAs. Restricted cubic splines (RCS) were applied to assess the possible dose-response relationships. Compared to the low PAH exposure group, the high-exposure group had higher levels of 5-hydroxytryptamine (5-HT), epinephrine (E), and acetylcholine (ACh), and lower levels of acetylcholinesterase (AChE). 1-OHP had a dose-response relationship with malondialdehyde (MDA), dopamine (DA), 5-HT, and AChE (P for overall associations < 0.05). There were 19 differentially expressed microRNAs in microarray analysis, significantly enriched in the cell membrane, molecular binding to regulate transcription, and several signaling pathways such as PI3K-Akt. And in the validation stage, miR-885-5p, miR-20a-5p, and let-7i-3p showed differences in the low and high-exposure groups (P < 0.05). Changes in neurotransmitters and microRNA expression levels among the coal miners were associated with PAH exposure. Their biological functions are mainly related to the transcriptional regulation of nervous system diseases or signaling pathways of disorders. These findings provide new insights for future research of PAH neurotoxicity.

Effect of Club cell secretory proteins on the association of tobacco smoke and PAH co-exposure with lung function decline: A longitudinal observation of Chinese coke oven workers.

BACKGROUND: Exposure to polycyclic aromatic hydrocarbons (PAH) and tobacco smoke is associated with epithelial damage and reduced lung function. Club cell secretory protein (CC16) is a known biomarker for lung epithelial cells. However, the potential relationships between PAH and tobacco smoke exposure, CC16 levels, and reduced lung function remain unclear. OBJECTIVES: This longitudinal study aimed to explore the potential role of CC16 in the association of tobacco smoke and PAH co-exposure with lung function. METHODS: We enrolled 313 workers from a coking plant in China in 2014 and followed them up in 2019. The concentrations of PAH and nicotine metabolites in urine were determined using high-performance liquid chromatography (HPLC) with a fluorescence detector and HPLC-tandem mass spectrometry, respectively. The plasma CC16 concentration was determined using an enzyme-linked immunosorbent assay. RESULTS: An analysis of the generalized estimating equation showed that each 1-unit increase in log-transformation of the last tertile of trans-3'-hydroxycotinine (3HC) was associated with a 3.30 ng/ml decrease in CC16. Restricted cubic spline analysis revealed a significant nonlinear dose-effect association between cotinine (COT) and CC16 (Pnonlinear = 0.018). In the low- CC16 subgroup, we found a significant association between total nicotine metabolites and forced vital capacity (FVC%) (ß: 1.45, 95% CI: 2.87, -0.03), and the associations of nicotine (NIC), COT, and 3HC with FVC% were all of marginal significance. High levels of total hydroxyl polycyclic aromatic hydrocarbons (ΣOH-PAH) and NIC in the urine had an interactive effect on the decline of CC16 (P < 0.05). Cross-lagged panel analysis indicated that the decrease in CC16 preceded the decrease in FVC%. CC16 mediated the association between elevated nicotine metabolites and decreased FVC% in the low- CC16 subgroup. CONCLUSIONS: CC16 plays an essential role in the association of PAH and tobacco smoke exposure with reduced lung function. Coke oven workers with low plasma CC16 levels are more likely to experience decreased lung function after tobacco smoke exposure.

The interaction effects of secondhand smoke exposure and overweight on the prevalence of hypertension in Chinese coke oven workers and NHANES participants (2013-2016).

BACKGROUND: The prevalence of hypertension may be affected by environmental pollution and personal behavior. OBJECTIVES: We aimed to evaluate the interaction effects of secondhand smoke exposure and overweight on hypertension. METHODS: In this cross-sectional study, a total of 627 workers from a coking plant in China and 1011 individuals from the NHANES database in the United States from 2013 to 2016 were selected as the research participants. The concentrations of 11 urinary polycyclic aromatic hydrocarbons (PAHs) metabolites and 3 tobacco metabolites were measured. An interaction effect was tested in the modified Poisson regression models. RESULTS: For smokers among Chinese coke oven workers, the only statistically significant positive association was with hypertension in the highest tertile of nicotine metabolized ratio (NMR) (PR: 1.539, 95% CI: 1.013-2.337). Nonsmoking Chinese workers with 3rd tertile urinary nicotine levels were associated with a 114.8% significantly increased prevalence of hypertension (PR: 2.148, 95% CI: 1.025-4.500) compared to nonsmokers 1st tertile with nicotine levels. Association between tobacco exposure and hypertension is possibly modified by PAHs exposure (PR: 2.335, 95% CI: 0.933-5.841). Nonsmokers in the NHANES database with high urinary nicotine levels were associated with a 17.3% significantly increased prevalence of hypertension (PR: 1.173, 95% CI: 1.028-1.338) compared to those with low nicotine levels. We observed that overweight people with high nicotine levels had a significantly higher likelihood of hypertension than no overweight people with low nicotine levels among nonsmoking Chinese coke oven workers and NHANES participants (PR = 4.686, 95% CI: 1.488-14.754; PR = 1.251, 95% CI: 1.039-1.506). CONCLUSIONS: Tobacco exposure and overweight are important risk factors for hypertension, and secondhand smoke exposure and overweight have an interactive effect on the incidence of hypertension in nonsmoking Chinese coke oven workers and NHANES participants.

Interaction of polycyclic aromatic hydrocarbon exposure and high-fasting plasma glucose on lung function decline in coke oven workers: a cross-lagged panel analysis.

Individuals with abnormal fasting plasma glucose (FPG) may be more susceptible to lung diseases associated with environmental pollutants. A cross-sectional survey of 629 workers in 2017 and a panel study of 304 workers from 2014 to 2019 were performed in China. The results showed that elevated total hydroxylated polycyclic aromatic hydrocarbon (ΣOH-PAH) concentration was associated with lower the percentage of predicted forced vital capacity (FVC%) among high-FPG workers (ß for the cross-sectional analysis: -1.78%, 95%CI: -2.92%, -0.64%; ß for the panel study: -1.10%, 95%CI: -2.19%, -0.02%). The absolute value of the cross-lagged path coefficient from FPG to FVC% (ß2 = -0.096) was significantly greater than that from FVC% to FPG (ß1 = 0.037). Our results suggest that FPG abnormalities may precede the lung function decline induced by PAH exposure and that high-FPG and high ΣOH-PAH levels have an interactive effect on lung function decline.

Assessment of NMR Logging for Estimating Hydraulic Conductivity in Glacial Aquifers.

Glacial aquifers are an important source of groundwater in the United States and require accurate characterization to make informed management decisions. One parameter that is crucial for understanding the movement of groundwater is hydraulic conductivity, K. Nuclear magnetic resonance (NMR) logging measures the NMR response associated with the water in geological materials. By utilizing an external magnetic field to manipulate the nuclear spins associated with 1 H, the time-varying decay of the nuclear magnetization is measured. This logging method could provide an effective way to estimate K at submeter vertical resolution, but the models that relate NMR measurements to K require calibration. At two field sites in a glacial aquifer in central Wisconsin, we collected a total of four NMR logs and obtained measurements of K in their immediate vicinity with a direct-push permeameter (DPP). Using a bootstrap algorithm to calibrate the Schlumberger-Doll Research (SDR) NMR-K model, we estimated K to within a factor of 5 of the DPP measurements. The lowest levels of accuracy occurred in the lower-K (K < 10-4  m/s) intervals. We also evaluated the applicability of prior SDR model calibrations. We found the NMR calibration parameters varied with K, suggesting the SDR model does not incorporate all the properties of the pore space that control K. Thus, the expected range of K in an aquifer may need to be considered during calibration of NMR-K models. This study is the first step toward establishing NMR logging as an effective method for estimating K in glacial aquifers.

Telomere length mediates the association between polycyclic aromatic hydrocarbons exposure and abnormal glucose level among Chinese coke oven plant workers.

INTRODUCTION: Diabetes is a chronic and complex disease determined by environmental and genetic factors. This study aimed to investigate the association between polycyclic aromatic hydrocarbons (PAHs) exposure and fasting blood glucose levels and telomere length among coke-oven plant workers, to explore potential role of telomere length (TL) in the association between PAHs exposure and abnormal glucose level. METHODS: The cross-sectional survey was conducted in 2017. The high-performance liquid chromatography mass spectrometry (HPLC-MS) was used to detect 11 urine biomarkers of PAHs exposure. TL was measured using the Real-time quantitative polymerase chain reaction (RT-qPCR) method. Logistic regression model, the modified Poisson regression models, and mediation analysis were used to evaluate the associations between PAHs exposure, TL, and abnormal glucose. RESULTS: The results showed that the urinary 1-hydroxypyrene (1-PYR) was positively related to abnormal glucose in a dose-dependent manner (Ptrend = 0.007), the prevalence ratio of abnormal glucose was 8% (95% CI: 1.01-1.16) higher in 3rd tertile of urinary 1-PYR levels. Urinary 1-PYR in the 2nd tertile and 3rd tertile were associated with a 53% (OR = 0.47, 95% CI: 0.28-0.79) and 59% (OR = 0.41, 95% CI: 0.23-0.76) higher risk of shortening TL. And there was a negatively association between 1-PYR and TL in a dose-dependent manner (Ptrend = 0.045). We observed that the association between 1-PYR and abnormal glucose was more significantly positive among participants with median TL level (Ptrend = 0.006). In addition, mediation analysis showed the TL could explain 11.7% of the effect of abnormal glucose related to PAHs exposure. CONCLUSIONS: Our findings suggested the effect of abnormal glucose related to PAHs exposure was mediated by telomere length in coke oven plant workers.

A Physically Based Approach for Estimating Hydraulic Conductivity from HPT Pressure and Flowrate.

The hydraulic profiling tool (HPT) is widely used to generate profiles of relative permeability vs. depth. In this work, prior numerical modeling results are used to develop a relationship between probe advance rate V (cm/s), probe diameter D (cm), water injection rate Q (mL/min), corrected pressure Pc (psi), and hydraulic conductivity K (feet/d) [Formula: see text] where E is an empirically derived hydraulic efficiency factor. The relationship is validated by 23 HPT profiles that, after averaging K vertically, were similar to slug test results in adjoining monitoring wells. The best fit value of E for these profiles was 2.02. This equation provides a physically based approach for generating hydraulic conductivity profiles with HPT tooling.

Neurobehavioral performance of PAH exposure in male coal miners in Shanxi, China: a cross-sectional study.

OBJECTIVE: Coal miners are exposed to polycyclic aromatic hydrocarbons (PAHs), a group of neurotoxicants formed and released during incomplete combustion of coal. High levels of anxiety and depression have been reported in coal miners, but little is known about neurobehavioral functions in populations that are occupationally exposed to PAHs. We tested neurobehavioral performance in coal miners and correlated it with levels of urinary markers of PAH exposure. METHODS: Levels of urinary PAH metabolites were measured in 652 male coal miners as an indicator of exposure. Subjects were divided into a high-exposure group and a low-exposure group based on the median level of total PAH metabolites. A neurobehavioral core test battery and a questionnaire were used to assess neurobehavioral performance and collect demographic information, respectively. RESULTS: The median level of total PAH metabolites in urine was 4.88 µmol/mol creatinine. Highly exposed workers exhibited more fatigue-inertia than less-exposed workers (p < 0.05), and had lower scores in forward digit span, digit symbol, and Benton visual retention tests (p < 0.05). Multiple linear regression indicated that age, education, and shift work were significantly correlated with test scores. CONCLUSIONS: PAH exposure may be associated with neurobehavioral alterations, which should be monitored in coal miners to prevent neurobehavioral disorders.

Simulation Assessment of Direct Push Injection Logging for High-Resolution Aquifer Characterization.

Direct push injection logging (DPIL) has become one of the most widely used approaches for obtaining vertical profiles of hydraulic conductivity (K) in environmental site investigations. Despite its widespread use, however, there has been no rigorous analysis of the underlying physical processes that take place during DPIL or how the approach would perform under different hydrogeological and operating conditions. We address these issues through a series of numerical simulations. Results show that the ratio of DPIL injection rate over pressure can be used for direct determination of K when K is >10-6  m/s. When K is <10-6  m/s and specific storage (Ss) is >10-3 /m, the ratio becomes increasingly sensitive to Ss; in that case, additional information on Ss is needed for reliable K estimation. For unconsolidated formations of moderate K or higher, the ratio of injection rate over pressure should provide a reasonable K estimate when Ss is <10-3 /m. Although water injection at previous depths during continuous DPIL has only a small impact on the pressure response measured at the current injection depth, probe advancement can have a significant impact when K and Ss are small. Consequently, in fine-grained materials, the advancement-generated pore water pressure increase can comprise a large portion of the measured pressure response. To diminish the impact of probe advancement in such materials, advancement speed should be kept as low as possible (e.g., 0.5 cm/s).

Field Investigation of a New Recharge Approach for ASR Projects in Near-Surface Aquifers.

Aquifer storage and recovery (ASR) is the artificial recharge and temporary storage of water in an aquifer when water is abundant, and recovery of all or a portion of that water when it is needed. One key limiting factor that still hinders the effectiveness of ASR is the high costs of constructing, maintaining, and operating the artificial recharge systems. Here we investigate a new recharge method for ASR in near-surface unconsolidated aquifers that uses small-diameter, low-cost wells installed with direct-push (DP) technology. The effectiveness of a DP well for ASR recharge is compared with that of a surface infiltration basin at a field site in north-central Kansas. The performance of the surface basin was poor at the site due to the presence of a shallow continuous clay layer, identified with DP profiling methods, that constrained the downward movement of infiltrated water and significantly reduced the basin recharge capacity. The DP well penetrated through this clay layer and was able to recharge water by gravity alone at a much higher rate. Most importantly, the costs of the DP well, including both the construction and land costs, were only a small fraction of those for the infiltration basin. This low-cost approach could significantly expand the applicability of ASR as a water resources management tool to entities with limited fiscal resources, such as many small municipalities and rural communities. The results of this investigation demonstrate the great potential of DP wells as a new recharge option for ASR projects in near-surface unconsolidated aquifers.

NMR Logging to Estimate Hydraulic Conductivity in Unconsolidated Aquifers.

Nuclear magnetic resonance (NMR) logging provides a new means of estimating the hydraulic conductivity (K) of unconsolidated aquifers. The estimation of K from the measured NMR parameters can be performed using the Schlumberger-Doll Research (SDR) equation, which is based on the Kozeny-Carman equation and initially developed for obtaining permeability from NMR logging in petroleum reservoirs. The SDR equation includes empirically determined constants. Decades of research for petroleum applications have resulted in standard values for these constants that can provide accurate estimates of permeability in consolidated formations. The question we asked: Can standard values for the constants be defined for hydrogeologic applications that would yield accurate estimates of K in unconsolidated aquifers? Working at 10 locations at three field sites in Kansas and Washington, USA, we acquired NMR and K data using direct-push methods over a 10- to 20-m depth interval in the shallow subsurface. Analysis of pairs of NMR and K data revealed that we could dramatically improve K estimates by replacing the standard petroleum constants with new constants, optimal for estimating K in the unconsolidated materials at the field sites. Most significant was the finding that there was little change in the SDR constants between sites. This suggests that we can define a new set of constants that can be used to obtain high resolution, cost-effective estimates of K from NMR logging in unconsolidated aquifers. This significant result has the potential to change dramatically the approach to determining K for hydrogeologic applications.