Appalachian mountaintop mining particulate matter induces neoplastic transformation of human bronchial epithelial cells and promotes tumor formation

Analyses of oxidative DNA damage among coal vendors via single cell gel electrophoresis and quantification of 8-hydroxy-2'-deoxyguanosine

Looking at the development status of Nigeria and other developing nations, most low-income and rural households often use coal as a source of energy which necessitates its trade very close to the communities. Moreover, the effects of exposure to coal mining activities are rarely explored or yet to be studied, not to mention the numerous street coal vendors in Nigeria. This study investigated the oxidative stress levels in serum and urine through the biomarker 8-OHdG and DNA damage via single cell gel electrophoresis (alkaline comet assay). Blood and urine levels of 8-OHdG from 130 coal vendors and 130 population-based controls were determined by ELISA. Alkaline comet assay was also performed on white blood cells for DNA damage. The average values of 8-OHdG in serum and urine of coal vendors were 22.82 and 16.03 ng/ml respectively, which were significantly greater than those detected in controls (p < 0.001; 15.46 and 10.40 ng/ml of 8-OHdG in serum and urine respectively). The average tail length, % DNA in tail and olive tail moment were 25.06 μm, 18.71% and 4.42 respectively for coal vendors. However, for controls, the average values were 4.72 μm, 3.63% and 1.50 for tail length, % DNA in tail and olive tail moment respectively which were much lower than coal vendors (p < 0.001). Therefore, prolonged exposure to coal dusts could lead to higher serum and urinary 8-OHdG and significant DNA damage in coal vendors observed in tail length, % DNA in tail, and olive tail moment by single cell gel electrophoresis. It is therefore established that coal vendors exhibit a huge risk from oxidative stress and assessment of 8-OHdG with single cell gel electrophoresis has proven to be a feasible tool as biomarkers of DNA damage.

Spatial distribution of selenium and other potentially toxic elements surrounding mountaintop coal mines in the Elk Valley, British Columbia, Canada

Despite the extensive use of mountaintop coal mining in the Elk Valley, British Columbia, Canada's largest metallurgical coal-producing region, little is known about the transport and deposition of fugitive dust emissions within its mountain landscape. This study aimed to assess the extent and spatial distribution of selenium and other potentially toxic elements (PTEs) near the town of Sparwood originating from fugitive dust emitted from two mountaintop coal mines. To achieve these objectives concentrations of 47 elements within moss tissues of Hylocomium splendens, Pleurozium schreberi, and Ptilium crista-castrensis were analyzed from 19 locations between May 29 to June 1, 2022. Contamination factors were then calculated to identify areas of contamination, along with generalized additive models to assess the relationship between selenium and the mines. Finally, Pearson correlation coefficients were calculated between selenium and other PTEs to determine which exhibited similar behaviour. This study found that selenium concentrations are a function of proximity to mountaintop mines, and the region's topographic features and prevailing wind patterns play a role in the transport and deposition of fugitive dust. Contamination is highest immediately surrounding mines and decreases at increasing distances, with the region's steep mountain ridges shielding the deposition of some fugitive dust when acting as a geographic barrier between adjacent valleys. Furthermore, silver, germanium, nickel, uranium, vanadium, and zirconium were identified as other PTEs of concern. The implications of this study are significant as it demonstrated the extent and spatial distribution of contaminants originating from fugitive dust emissions surrounding mountaintop mines and some of the controls to its distribution in mountain regions. As Canada and other mining jurisdictions look to expand critical mineral development, it will be important for proper risk assessment and mitigation in mountain regions to limit community and environmental exposure to contaminants within fugitive dust.

Maternal proximity to mountain-top removal mining and birth defects in Appalachian Kentucky, 1997–2003

Extraction of coal through mountaintop removal mining (MTR) alters many dimensions of the landscape. Explosive blasts, exposed rock, and coal washing have the potential to pollute air and water. Previous research suggests that infants born to mothers living in areas with MTR have a higher prevalence of birth defects. In this cross-sectional study, we further examine the relationship between MTR activity and several types of birth defects. Maternal exposure to MTR was assessed using remote sensing data from Skytruth, which captures MTR activity in the Central Appalachian region of the United States. Active MTR area was quantified within a five-kilometer buffer surrounding geocoded maternal address captured on birth records for live births to Appalachian Kentucky mothers between 1997 and 2003 (N = 95,581). We assigned high, medium, and low exposure based on the tertile of total MTR area within 5-km, and births with no MTR within this buffer were assigned zero exposure. The presence or absence of a birth defect grouped into six major organ systems was identified using birth records alone. Finally, we applied conditional multiple imputation for variables with missing values before conducting separate multivariable log-binomial regression models for each birth defect group. Prevalence ratio (PR) estimates were adjusted for individual level covariates from birth records. The prevalence of gastro-intestinal defects was significantly higher in birth records with high and low active MTR exposure compared to records with no exposure. (High exposure: PR = 1.99, 95% CI = 1.14–3.47; low exposure PR = 1.88, 95% CI = 1.06–3.31). This study supports some of the existing findings of previous ecological studies. Research addressing the relationship between gastro-intestinal birth defects and MTR coal mining is warranted but should carefully consider temporal dimensions of exposure.

Identifying exposure pathways mediating adverse birth outcomes near active surface mines in Central Appalachia

Background:

Previous work has determined an association between proximity to active surface mining within Central Appalachia and an increased risk of preterm birth (PTB) and low birthweight (LBW). Multiple potential exposure pathways may exist; however, including inhalation of particulate matter (airshed exposure), or exposure to impacted surface waters (watershed exposure). We hypothesize that this relationship is mediated by exposure to contaminants along one or both of these pathways.

Methods:

We geolocated 194,084 birth records through health departments in WV, KY, VA, and TN between 1990 and 2015. We performed a mediation analysis, iteratively including within our models: (a) the percent of active surface mining within 5 km of maternal residence during gestation; (b) the cumulative surface mining airshed trajectories experienced during gestation; and (c) the percent of active surface mining occurring within the watershed of residency during gestation.

Results:

Our baseline models found that active surface mining was associated with an increased odds of PTB (1.09, 1.05–1.13) and LBW (1.06, 1.02–1.11), controlling for individual-level predictors. When mediators were added to the baseline model, the association between active mining and birth outcomes became nonsignificant (PTB: 0.48, 0.14–1.58; LBW 0.78, 0.19–3.00), whereas the association between PTB and LBW remained significant by airshed exposure (PTB: 1.14, 1.11–1.18; LBW: 1.06, 1.03–1.10).

Conclusions:

Our results found that surface mining airsheds at least partially explained the association between active mining and adverse birth outcomes, consistent with a hypothesis of mediation, while mediation via the watershed pathway was less evident.

Hydrogels and Hydrogel Nanocomposites: Enhancing Healthcare through Human and Environmental Treatment

Humans are constantly exposed to exogenous chemicals throughout their life, which can lead to a multitude of negative health impacts. Advanced materials can play a key role in preventing or mitigating these impacts through a wide variety of applications. The tunable properties of hydrogels and hydrogel nanocomposites (e.g., swelling behavior, biocompatibility, stimuli responsiveness, functionality, etc.) have deemed them ideal platforms for removal of environmental contaminants, detoxification, and reduction of body burden from exogenous chemical exposures for prevention of disease initiation, and advanced treatment of chronic diseases, including cancer, diabetes, and cardiovascular disease. In this review, three main junctures where the use of hydrogel and hydrogel nanocomposite materials can intervene to positively impact human health are highlighted: 1) preventing exposures to environmental contaminants, 2) prophylactic treatments to prevent chronic disease initiation, and 3) treating chronic diseases after they have developed.

Impacts of Coal Use on Health

This article reviews evidence for the public health impacts of coal across the extraction, processing, use, and waste disposal continuum. Surface coal mining and processing impose public health risks on residential communities through air and water pollution. Burning coal in power plants emits more nitrogen oxides, sulfur dioxide, particulate matter, and heavy metals per unit of energy than any other fuel source and impairs global public health. Coal ash disposal exposes communities to heavy metals and particulate matter waste. Use of coal in domestic households causes public health harm concentrated in developing nations. Across the coal continuum, adverse impacts are disproportionately felt by persons of poor socioeconomic status, contributing to health inequities. Despite efforts to develop renewable energy sources, coal use has not declined on a global scale. Concentrated efforts to eliminate coal as an energy source are imperative to improve public health and avert serious climate change consequences.

Mountaintop removal mining and multiple illness symptoms: A latent class analysis

BACKGROUND

Mountaintop removal mining has been associated with multiple types of disease outcomes for populations living nearby. The current study tested whether latent classes identifying people with symptoms from multiple organ systems were associated with residence in mountaintop mining communities.

METHODS

We used data from three cross-sectional household community surveys conducted in three Appalachian states (N = 2756). The surveys contained information on 29 recent illness symptoms grouped into eight organ systems (respiratory, cardiovascular, gastrointestinal, musculoskeletal, skin, eye-ear-nose-throat, neurological, and other.) We identified latent classes, and then tested whether classes with higher probabilities of multiple symptoms would be associated with residence in mountaintop removal areas after control for covariates.

RESULTS

Three latent classes were identified, including a low-symptom referent class, an intermediate class, and a class with high symptom probability across organ systems. Controlling for covariates, latent classes characterized by intermediate and high multi-symptom probabilities were significantly associated with residence near mountaintop removal mining, with the highest odds ratio for the MTR versus control condition for the high multi-symptom group (OR = 2.17, 95% CI = 1.80-2.61).

CONCLUSIONS

Symptoms across multiple organ systems were related to residential proximity to mountaintop removal mining. Prior research has established multiple environmental contaminants related to mining that may contribute to poor population health through more than one exposure route or chemical of concern.

Systematic review of community health impacts of mountaintop removal mining

BACKGROUND

The objective of this evaluation is to understand the human health impacts of mountaintop removal (MTR) mining, the major method of coal mining in and around Central Appalachia. MTR mining impacts the air, water, and soil and raises concerns about potential adverse health effects in neighboring communities; exposures associated with MTR mining include particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), metals, hydrogen sulfide, and other recognized harmful substances.

METHODS

A systematic review was conducted of published studies of MTR mining and community health, occupational studies of MTR mining, and any available animal and in vitro experimental studies investigating the effects of exposures to MTR-mining-related chemical mixtures. Six databases (Embase, PsycINFO, PubMed, Scopus, Toxline, and Web of Science) were searched with customized terms, and no restrictions on publication year or language, through October 27, 2016. The eligibility criteria included all human population studies and animal models of human health, direct and indirect measures of MTR-mining exposure, any health-related effect or change in physiological response, and any study design type. Risk of bias was assessed for observational and experimental studies using an approach developed by the National Toxicology Program (NTP) Office of Health Assessment and Translation (OHAT). To provide context for these health effects, a summary of the exposure literature is included that focuses on describing findings for outdoor air, indoor air, and drinking water.

RESULTS

From a literature search capturing 3088 studies, 33 human studies (29 community, four occupational), four experimental studies (two in rat, one in vitro and in mice, one in C. elegans), and 58 MTR mining exposure studies were identified. A number of health findings were reported in observational human studies, including cardiopulmonary effects, mortality, and birth defects. However, concerns for risk of bias were identified, especially with respect to exposure characterization, accounting for confounding variables (such as socioeconomic status), and methods used to assess health outcomes. Typically, exposure was assessed by proximity of residence or hospital to coal mining or production level at the county level. In addition, assessing the consistency of findings was challenging because separate publications likely included overlapping case and comparison groups. For example, 11 studies of mortality were conducted with most reporting higher rates associated with coal mining, but many of these relied on the same national datasets and were unable to consider individual-level contributors to mortality such as poor socioeconomic status or smoking. Two studies of adult rats reported impaired microvascular and cardiac mitochondrial function after intratracheal exposure to PM from MTR-mining sites. Exposures associated with MTR mining included reports of PM levels that sometimes exceeded Environmental Protection Agency (EPA) standards; higher levels of dust, trace metals, hydrogen sulfide gas; and a report of increased public drinking water violations.

DISCUSSION

This systematic review could not reach conclusions on community health effects of MTR mining because of the strong potential for bias in the current body of human literature. Improved characterization of exposures by future community health studies and further study of the effects of MTR mining chemical mixtures in experimental models will be critical to determining health risks of MTR mining to communities. Without such work, uncertainty will remain regarding the impact of these practices on the health of the people who breathe the air and drink the water affected by MTR mining.

Environmental health disparities in the Central Appalachian region of the United States

Health disparities that cannot be fully explained by socio-behavioral factors persist in the Central Appalachian region of the United States. A review of available studies of environmental impacts on Appalachian health and analysis of recent public data indicates that while disparities exist, most studies of local environmental quality focus on the preservation of nonhuman biodiversity rather than on effects on human health. The limited public health studies available focus primarily on the impacts of coal mining and do not measure personal exposure, constraining the ability to identify causal relationships between environmental conditions and public health. Future efforts must engage community members in examining all potential sources of environmental health disparities to identify effective potential interventions.

Induction of cancer-associated fibroblast-like cells by carbon nanotubes dictates its tumorigenicity

Tumor microenvironment has been recognized as a key determinant of tumor formation and metastasis, but how tumor microenvironment is affected by nanomaterials is essentially unknown. Here, we investigated whether carbon nanotubes (CNTs), a widely used nanomaterial with known carcinogenic potential, can affect cancer-associated fibroblasts (CAFs), which are a key component of tumor microenvironment that provides necessary support for tumor growth. We show for the first time that single-walled CNT and to a lesser extent multi-walled and its COOH-functionalized form induced CAF-like cells, which are non-tumorigenic in animals, but promote tumor growth of human lung carcinoma and CNT-transformed lung epithelial cells. The mechanism by which CNT-induced CAF-like cells promote tumor growth involved the acquisition of cancer stem cells (CSCs) in cancer population. Gene knockdown experiments showed that an expression of podoplanin on CAF-like cells is essential for their effects, indicating the functional role of CAF-like cells and podoplanin in CNT tumorigenic process. Our findings unveil a novel mechanism of CNT-induced carcinogenesis through the induction of CAF-like cells that support CSCs and drive tumor formation. Our results also suggest the potential utility of podoplanin as a mechanism-based biomarker for rapid screening of carcinogenicity of CNTs and related nanomaterials for their safer design.

Comparative In Vitro Biological Toxicity of Four Kinds of Air Pollution Particles

Accumulating epidemiological evidence indicates that exposure to fine air pollution particles (APPs) is associated with a variety of adverse health effects. However, the exact physiochemical properties and biological toxicities of fine APPs are still not well characterized. We collected four types of fine particle (FP) (diesel exhaust particles [DEPs], natural organic combustion [NOC] ash, synthetic organic combustion [SOC] ash, and yellow sand dust [YSD]) and investigated their physicochemical properties and in vitro biological toxicity. DEPs were almost entirely composed of ultrafine particles (UFPs), while the NOC, SOC, and YSD particles were a mixture of UFPs and FPs. The main elements in the DEPs, NOC ash, SOC ash, and YSD were black carbon, silicon, black carbon, and silicon, respectively. DEPs exhibited dose-dependent mutagenicity even at a low dose in Salmonella typhimurium TA 98 and 100 strains in an Ames test for genotoxicity. However, NOC, SOC, and YSD particles did not show any mutagenicity at high doses. The neutral red uptake assay to test cell viability revealed that DEPs showed dose-dependent potent cytotoxicity even at a low concentration. The toxicity of DEPs was relatively higher than that of NOC, SOC, and YSD particles. Therefore, these results indicate that among the four FPs, DEPs showed the highest in vitro biological toxicity. Additional comprehensive research studies such as chemical analysis and in vivo acute and chronic inhalation toxicity tests are necessary to determine and clarify the effects of this air contaminant on human health.

Lung cancer among coal miners, ore miners and quarrymen: smoking-adjusted risk estimates from the synergy pooled analysis of case-control studies

OBJECTIVES

Working in mines and quarries has been associated with an elevated lung cancer risk but with inconsistent results for coal miners. This study aimed to estimate the smoking-adjusted lung cancer risk among coal miners and compare the risk pattern with lung cancer risks among ore miners and quarrymen.

METHODS

We estimated lung cancer risks of coal and ore miners and quarrymen among 14 251 lung cancer cases and 17 267 controls from the SYNERGY pooled case-control study, controlling for smoking and employment in other at-risk occupations.

RESULTS

Ever working as miner or quarryman (690 cases, 436 controls) was associated with an elevated odds ratio (OR) of 1.55 [95% confidence interval (95% CI) 1.34-1.79] for lung cancer. Ore miners (53 cases, 24 controls) had a higher OR (2.34, 95% CI 1.36-4.03) than quarrymen (67 cases, 39 controls; OR 1.92, 95% CI 1.21-3.05) and coal miners (442 cases, 297 controls; OR 1.40, 95% CI 1.18-1.67), but CI overlapped. We did not observe trends by duration of exposure or time since last exposure.

CONCLUSIONS

This pooled analysis of population-based studies demonstrated an excess lung cancer risk among miners and quarrymen that remained increased after adjustment for detailed smoking history and working in other at-risk occupations. The increase in risk among coal miners were less pronounced than for ore miners or quarrymen.