Polymorphisms in metabolism and repair genes affects DNA damage caused by open-cast coal mining exposure

The Impact of Genetic Polymorphisms for Detecting Genotoxicity in Workers Occupationally Exposed to Metals: A Systematic Review

The present study aims to provide a systematic review of studies on the essential and nonessential metal exposure at occupational level, genotoxicity, and polymorphisms and to answer the following questions: Are genetic polymorphisms involved in metal-induced genotoxicity? In this study, 14 publications were carefully analyzed in this setting. Our results pointed out an association between polymorphism and genotoxicity in individuals exposed to metals, because 13 studies (out of 14) revealed positive relations between genotoxicity and polymorphisms in xenobiotics metabolizing and DNA repair genes. Regarding the quality of these findings, they can be considered reliable, as the vast majority of the studies (12 out of 14) were categorized as strong or moderate in the quality assessment. Taken as a whole, occupational exposure to metals (essentials or not) induces genotoxicity in peripheral blood or oral mucosa cells. Additionally, professional individuals with certain genotypes may present higher or lower DNA damage as well as DNA repair potential, which will certainly impact the level of DNA damage in the occupational environment.

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.

Influence of genetic polymorphisms of Hg metabolism and DNA repair on the frequencies of micronuclei, nucleoplasmic bridges, and nuclear buds in communities living in gold mining areas

Fishing communities living near gold mining areas are at increased risk of mercury (Hg) exposure via bioaccumulation of methylmercury (MeHg) in fish. This exposure has been linked to health effects that may be triggered by genotoxic events. Genetic polymorphisms play a role in the risk associated with Hg exposure. This study evaluated the effect of single nucleotide polymorphisms (SNPs) in metabolic and DNA repair genes on genetic instability and total hair Hg (T-Hg) levels in 78 individuals from "La Mojana" in northern Colombia and 34 individuals from a reference area. Genetic instability was assessed by the frequency of micronuclei (MNBN), nuclear buds (NBUDS), and nucleoplasmic bridges (NPB). We used a Poisson regression to assess the influence of SNPs on T-Hg levels and genetic instability, and a Bayesian regression to examine the interaction between Hg detoxification and DNA repair. Among exposed individuals, carriers of XRCC1Arg399Gln had a significantly higher frequency of MNBN. Conversely, the XRCC1Arg194Trp and OGG1Ser326Cys polymorphisms were associated with lower frequencies of MNBN. XRCC1Arg399Gln, XRCC1Arg280His, and GSTM1Null carriers showed lower NPB frequencies. Our results also indicated that individuals with the GSTM1Nulland GSTT1null polymorphisms had a 1.6-fold risk for higher T-Hg levels. The Bayesian model showed increased MNBN frequencies in carriers of the GSTM1Null polymorphism in combination with XRCC1Arg399Gln and increased NBUDS frequencies in the GSTM1Null carriers with the XRCC3Thr241Met and OGG1Ser326Cys alleles. The GSTM1+ variant was found to be a protective factor in individuals carrying OGG1Ser326Cys (MNBN) and XRCC1Arg280His (NPB); the GSTT1+ polymorphism combined with XRCCArg194Trp also modulated lower MNBN frequencies, while GSTT1+ carriers with the XRCC1Arg399Gln allele showed lower NPB frequencies. Consistent with GSTM1, GSTT1Null carriers with XRCC3Thr241Met showed increased NBUDS frequency. With the rise of gold mining activities, these approaches are vital to identify and safeguard populations vulnerable to Hg's toxic effects.

Use of micronucleus cytome assays with buccal cells for the detection of genotoxic effects: A systematic review and meta-analysis of occupational exposures to metals

Micronucleus (MN) assays with buccal cells are at present widely used to investigate occupational exposures to genotoxic carcinogens. This article describes their use for the monitoring of metal exposed workers. We found in total 73 relevant articles, in the majority (97 %) increased MN and/or other nuclear anomalies were reported. Most studies were realized in South East Asia and South America. A variety of different occupations was studied including welders, electroplaters, painters, workers in battery recycling and production, tannery workers, dental technicians, miners, workers in foundries and smelters, and also subjects working in waste recycling, glass, aluminum and steel production. In many investigations the effects increased with the duration of the working period. The quality of individual studies was evaluated with a quality score tool. The number of cells was in most studies sufficient and DNA-specific stains were used. However, many studies have shortcomings, e.g. they focused solely on MN formation and did not evaluate anomalies, which provide additional information about the stability of the genetic material and acute cytotoxic effects. Only 35 % of the investigations contain quantitative information about exposures to metals and other toxicants. In 6 of these studies, correlations were observed between the concentrations of specific metals (As, Pb, Cr, Cd) in body fluids and MN frequencies. Taken together, the available data indicate that the MN assay can be used to detect chromosomal damage in metal exposed groups; furthermore, it enables also comparisons between subgroups differing in regard to their exposure and allows an estimation of the efficiency of protective measures. The exposure of workers to metals is currently controlled with chemical analytical measurements only, MN assays with buccal cells could contribute to further improve the safety at workplaces as they reflect the biological consequences including synergistic and antagonistic interactions between toxicants.

Micronuclei, Pesticides, and Element Mixtures in Mining Contexts: The Hormetic Effect of Selenium

The contexts where there are mining and agriculture activities are potential sources of risk to human health due to contamination by chemical mixtures. These contexts are frequent in several Colombian regions. This study explored the potential association between the frequency of micronuclei and pesticides and elements in regions with ferronickel (Montelibano, Córdoba) and gold (Nechí, Antioquia) mining, and a closed native mercury mine (Aranzazu, Caldas), with an emphasis in the potential effect of selenium as a potential chelator. A cross-sectional study was carried out with 247 individuals. Sociodemographic, occupational, and toxicological variables were ascertained. Blood and urine samples were taken for pesticide analysis (5 organophosphates, 4 organochlorines, and 3 carbamates), 68 elements were quantified in hair, and micronuclei were quantified in lymphocytes. The mixtures of elements were grouped through principal component analysis. Prevalence ratios were estimated with robust variance Poisson regressions to explore associations. Interactions of selenium with toxic elements were explored. The highest concentrations of elements were in the active mines. The potentially most toxic chemical mixture was observed in the ferronickel mine. Pesticides were detected in a low proportion of participants (<2.5%), except paraoxon-methyl in blood (27.55%) in Montelibano and paraoxon-ethyl in blood (18.81%) in Aranzazu. The frequency of micronuclei was similar in the three mining contexts, with means between 4 to 7 (p = 0.1298). There was great heterogeneity in the exposure to pesticides and elements. The "hormetic effect" of selenium was described, in which, at low doses, it acts as a chelator in Montelibano and Aranzazu, and at high doses, it can enhance the toxic effects of other elements, maybe as in Nechí. Selenium can serve as a protective agent, but it requires adaptation to the available concentrations in each region to avoid its toxic effects.

Polycyclic aromatic hydrocarbons (PAHs): Updated aspects of their determination, kinetics in the human body, and toxicity

Polycyclic aromatic hydrocarbons (PAHs) are legacy pollutants of considerable public health concern. Polycyclic aromatic hydrocarbons arise from natural and anthropogenic sources and are ubiquitously present in the environment. Several PAHs are highly toxic to humans with associated carcinogenic and mutagenic properties. Further, more severe harmful effects on human- and environmental health have been attributed to the presence of high molecular weight (HMW) PAHs, that is PAHs with molecular mass greater than 300 Da. However, more research has been conducted using low molecular weight (LMW) PAHs). In addition, no HMW PAHs are on the priority pollutants list of the United States Environmental Protection Agency (US EPA), which is limited to only 16 PAHs. However, limited analytical methodologies for separating and determining HMW PAHs and their potential isomers and lack of readily available commercial standards make research with these compounds challenging. Since most of the PAH kinetic data originate from animal studies, our understanding of the effects of PAHs on humans is still minimal. In addition, current knowledge of toxic effects after exposure to PAHs may be underrepresented since most investigations focused on exposure to a single PAH. Currently, information on PAH mixtures is limited. Thus, this review aims to critically assess the current knowledge of PAH chemical properties, their kinetic disposition, and toxicity to humans. Further, future research needs to improve and provide the missing information and minimize PAH exposure to humans.

Chemical Composition and Toxicity of PM10 and PM0.1 Samples near Open-Pit Mines and Coal Power Stations

Particulate matter (PM) <10 μm in size represents an extremely heterogeneous and variable group of objects that can penetrate the human respiratory tract. The present study aimed to isolate samples of coarse and ultrafine PM at some distance from polluting industries (1−1.5 km from the border of open-cast mines). PM was collected from snow samples which allowed the accumulation of a relatively large amount of ultrafine particles (UFPs) (50−60 mg) from five objects: three open-cast mines, coal power plants, and control territories. The chemical composition of PM was examined using absorption spectroscopy, luminescence spectroscopy, high-performance liquid chromatography, X-ray diffraction (XRD), and X-ray fluorescence (XRF) analyses of solid particle material samples. Toxicity was assessed in human MRC-5 lung fibroblasts after 6 h of in vitro exposure to PM samples. The absorption spectra of all the samples contained a wide non-elementary absorption band with a maximum of 270 nm. This band is usually associated with the absorption of dissolved organic matter (DOM). The X-ray fluorescence spectra of all the studied samples showed intense lines of calcium and potassium and less intense lines of silicon, sulfur, chlorine, and titanium. The proliferation of MRC-5 cells that were exposed to PM0.1 samples was significantly (p < 0.01) lower than that of MRC-5 cells exposed to PM10 at the same concentration, except for PM samples obtained from the control point. PM0.1 samples—even those that were collected from control territories—showed increased genotoxicity (micronucleus, ‱) compared to PM10. The study findings suggest that UFPs deserve special attention as a biological agent, distinct from larger PMs.

Genotoxicity biomarkers in car repair workers from Barranquilla, a Colombian Caribbean City

Exposure to chemicals and particles generated in automotive repair shops is a common and underestimated problem. The objective of this study was to assess the genotoxic status of auto repair workers with (1) a questionnaire to gather sociodemographic information and self-reported exposure to hazardous chemicals and (2) measurement of various biochemical parameters. Blood and oral mucosa samples were collected from 174 male volunteers from Barranquilla, Colombia, aged 18-55 years: 87 were active car repairmen and 87 were individuals with no known exposure to hazardous chemicals. Peripheral blood lymphocytes were collected for the comet and cytokinesis-blocking micronucleus (CBMN) assays, while oral mucosal epithelium extracted to quantify micronucleated cells (MNC). DNA was extracted to assess polymorphisms in the DNA repair (XRCC1) and metabolism-related genes (GSTT1 and GSTM1) using PCR-RFLP. DNA damage and frequency of micronuclei (MN) in lymphocytes and oral mucosa were significantly higher in exposed compared to control group. In both groups genotypes and allelic variants for XRCC1 and GSTT1 met the Hardy-Weinberg equilibrium (HWE). In contrast, GSTM1 deviated from HWE. In the exposed group genotypic variants were not correlated with DNA damage or MN presence in cells. DNA damage and occurrence of MN in mucosa and lymphocytes correlated with age and time of service (occupational exposure ≥ 3 years). In summary, workers in car repair shops exhibited genotoxic effects depending upon exposure duration in the workplace which occurred independent of DNA repair XRCC1 gene and metabolism genes GSTT1 and GSTM1. Date demonstrate that health authorities improve air quality in auto repair facilities to avoid occupational DNA damage.

Study on the Spatial and Temporal Distribution Characteristics and Influencing Factors of Particulate Matter Pollution in Coal Production Cities in China

In recent years, with the continuous advancement of China's urbanization process, regional atmospheric environmental problems have become increasingly prominent. We selected 12 cities as study areas to explore the spatial and temporal distribution characteristics of atmospheric particulate matter in the region, and analyzed the impact of socioeconomic and natural factors on local particulate matter levels. In terms of time variation, the particulate matter in the study area showed an annual change trend of first rising and then falling, a monthly change trend of "U" shape, and an hourly change trend of double-peak and double-valley distribution. Spatially, the concentration of particulate matter in the central and southern cities of the study area is higher, while the pollution in the western region is lighter. In terms of social economy, PM_2.5 showed an "inverted U-shaped" quadratic polynomial relationship with Second Industry and Population Density, while it showed a U-shaped relationship with Generating Capacity and Coal Output. The results of correlation analysis showed that PM_2.5 and PM₁₀ were significantly positively correlated with NO₂, SO₂, CO and air pressure, and significantly negatively correlated with O₃ and air temperature. Wind speed was significantly negatively correlated with PM_2.5, and significantly positively correlated with PM₁₀. In terms of pollution transmission, the southwest area of Taiyuan City is a high potential pollution source area of fine particles, and the long-distance transport of PM_2.5 in Xinjiang from the northwest also has a certain contribution to the pollution of fine particles. This study is helpful for us to understand the characteristics and influencing factors of particulate matter pollution in coal production cities.

Evidence of micro-evolution in Crocidura russula from two abandoned heavy metal mines: potential use of Cytb, CYP1A1, and p53 as gene biomarkers

Heavy metals accumulated in the environment due to the mining industry may impact on the health of exposed wild animals with consequences at the population level via survival and selection of the most resistant individuals. The detection and quantification of shifts in gene frequencies or in the genetic structure in populations inhabiting polluted sites may be used as early indicators of environmental stress and reveal potential 'candidate gene biomarkers' for environmental health assessment. We had previously observed that specimens of the Greater white-toothed shrew (Crocidura russula) from two heavy metal mines in Southern Portugal (the Aljustrel and the Preguiça mines) carried physiological alterations compared to shrews from an unpolluted site. Here, we further investigated whether these populations showed genetic differences in genes relevant for physiological homeostasis and/or that are associated with pathways altered in animals living under chronic exposure to pollution, and which could be used as biomarkers. We analysed the mitochondrial cytochrome b (Cytb) gene and intronic and/or exonic regions of four nuclear genes: CYP1A1, LCAT, PRPF31, and p53. We observed (1) population differences in allele frequencies, types of variation, and diversity parameters in the Cytb, CYP1A1, and p53 genes; (2) purifying selection of Cytb in the mine populations; (3) genetic differentiation of the two mine populations from the reference by the p53 gene. Adding to our previous observations with Mus spretus, we provide unequivocal evidence of a population effect exerted by the contaminated environment of the mines on the local species of small mammals.

Cytokinesis-block micronucleus cytome (CBMN-CYT) assay and its relationship with genetic polymorphisms in welders

Fumes generated in the welding process are composed of micrometric and nanometric particles that form when metal fumes condense. The International Agency for Research on Cancer established that many compounds derived from the welding process are carcinogenic to humans. Still, there are few studies related to the role of genetic polymorphisms. This work aimed to analyze the influence of OGG1 Ser326Cys, XRCC1 Arg280His, XRCC1 Arg194Thr, XRCC1 Arg399Gln, XRCC3 Thr241Met, GSTM1, and GSTT1 gene polymorphisms on DNA damage of 98 subjects occupationally exposed to welding fumes and 100 non exposed individuals. The results showed that individuals exposed to welding fumes with XRCC3 Thr241Thr, XRCC3 Thr241Met, and GSTM1 null genotypes demonstrated a significantly higher micronucleus frequency in lymphocytes. In contrast, individuals with XRCC1 Arg399Gln and XRCC1 Gln399Gln genotypes had significant levels of NPBs. OGG1 326 Ser/Cys, OGG1 326 Cys/Cys, XRCC1 194Arg/Thr, XRCC1 194Thr/Thr, and GSTT1 null genotypes exhibited significantly higher apoptotic values. Also, XRCC1 194Arg/Trp, XRCC1 194Thr/Thr, and GSTM1 null genotype carriers had higher necrotic levels compared to XRCC1 194Arg/Arg and GSTM1 nonnull carriers. Compositional analysis revealed the presence of iron, manganese, silicon as well as particles smaller than 2 μm that adhere to each other and form agglomerates. These results may be associated with a mixture of components, such as nitrogen dioxide, carbon monoxide, and metallic fumes, leading to significant DNA damage and cell death processes. These findings demonstrated the importance of the association between individual susceptibility and DNA damage levels due to occupational exposure to welding fumes; and constitute one of the first studies carried out in exposed workers from Colombia.

The Importance of the Social License to Operate at the Investment and Operations Stage of Coal Mining Projects: Application using a Decision Support System

The Social License to Operate (SLO) and the Value Chain business model are basic elements that need to be considered both at the planning and operation stages of mining operations and in particular in coal mining projects. If a coal mining enterprise loses its SLO, it may face risks in operations, which may lead to value chain risks. One of the causes of enterprise failure as related to coal mining operations is the inability to reliably assess/manage risk holistically and the inability to understand that lack of SLO is a critical risk. Although financial risks are typically assessed for mining projects, lack of SLO risk should also be taken into account starting as early as the bankable feasibility study. Furthermore, as it is difficult to establish a proactive decision-making policy for SLO risk in coal mining operations, the Operational Risk Management (ORM) methodology is probably a good tool to apply towards that goal. For this reason, a Mining Operational Risk Management Model (MORMM) was developed to incorporate risk probabilities and risk severities evaluated by experts. The final risk assessment is coded using Risk Assessment Codes (RACs). A hypothetical scenario was developed utilizing the MORMM model in order to illustrate how risks can be managed during the SLO granting process. This scenario describes a hypothetical coal mining project evaluated by virtual risk evaluators under specific hazard categories. Risk evaluation involves the assessment of risk probability and risk severity. Through this scenario this paper presents ways: (i) to establish a baseline ORM process that will be applicable to any coal mining operation environment, and (ii) to provide a theoretical example to demonstrate how the method can be applied to coal mining operations. The resulting RACs can provide critical information to decision makers regarding the rejection, acceptance or re-engineering of the mining business plan.

Genetic damage in coal and uranium miners

Mining has a direct impact on the environment and on the health of miners and is considered one of the most hazardous occupations worldwide. Miners are exposed to several occupational health risks, including genotoxic substances, which may cause adverse health effects, such as cancer. This review summarizes the relation between DNA damage and mining activities, focusing on coal and uranium miners. The search was performed using electronic databases, including original surveys reporting genetic damage in miners. Additionally, a temporal bibliometric analysis was performed using an electronic database to create a map of cooccurrence terms. The majority of studies were performed with regard to occupational exposure to coal, whereas genetic damage was assessed mainly through chromosomal aberrations (CAs), micronuclei (MNs) and comet assays. The bibliometric analysis demonstrated associations of coal exposure with silicosis and pneumoconiosis, uranium miners with lung cancer and tumors and some associated factors, such as age, smoking, working time and exposure to radiation. Significantly higher DNA damage in miners compared to nonexposed groups was observed in most of the studies. The timeline reveals that classic biomarkers (comet assay, micronucleus test and chromosomal aberrations) are still important tools to assess genotoxic/mutagenic damage in occupationally exposed miners; however, newer studies concerning genetic polymorphisms and epigenetic changes in miners are being conducted. A major challenge is to investigate further associations between miners and DNA damage and to encourage further studies with miners of other types of ores.

Analysis of roadside air pollutant concentrations and potential health risk of exposure in Hanoi, Vietnam

The large number of vehicles plying in roads is the main cause of traffic jam and air pollution in Hanoi. In this study, the vehicle density and shares of different vehicle types, the traffic flow velocity and roadside air pollutants concentrations were monitored in Chua Boc street, a typical arterial road in the city. The shares of the motorcycle, car and bus fleets in the total on-road traffic in the street were 78.4-87.3, 12.3-20.2 and 0.4-1.4%, respectively. The high density of vehicles caused traffic jam during rush hours and considerably reduced the vehicle speed. The traffic flow velocity during non-rush and rush hours was found to vary from 26.4-34.5 and 10.3-12.1 km/h, respectively. The average concentrations of PM₁₀, PM_2.5, SO₂, NO₂, CO and NMVOC during the rush hours were the following: 117.1 ± 8.5, 65.2 ± 10.6, 113.5 ± 10.9, 138.5 ± 16.0, 6792 ± 998 and 451 ± 71 µg/m³, respectively, which were about 1.9-2.6 times above the levels during non-rush hours. The decrease in vehicle speed during rush hours were strongly correlated with the increase in concentration of PM₁₀ (R² = 0.732), PM_2.5 (R² = 0.685), SO₂ (R² = 0.578), NO₂ (R² = 0.738), CO (R² = 0.689) and NMVOC (R² = 0.747). High levels of these toxic air pollutants in Hanoi city posed a high health risk to humans. Facemask use was more popular among the motorcycle commuters and pedestrians, especially during rush hours, than among the people working for extended time period alongside of the street.

Distribution and health risk assessment of potentially toxic elements in soils around coal industrial areas: A global meta-analysis

Coal production and utilization are recognized as two principal sources of potentially toxic elements in the environment. Here the published literature (2008-2018) was searched to collect data on As, Ni, Cd, Cu, Cr, Hg, Pb and Zn concentrations in soils near different types of coal industrial areas such as coal mines, thermal power plants, coal chemical plants, coal mining cities and coal waster piles. The contamination levels of soils and associated health risks were assessed using global reference materials and multiple contamination indices. The results revealed that average concentrations of potentially toxic elements varied widely, yet most of them exceeded global averages in background soils and upper continental crust concentrations. Spatial distribution analysis suggested the concentrations of potentially toxic elements varied according to coalification and combustion conditions. Higher concentrations were found in Southeast Asia, South Europe, and North Africa compared with other regions. Assessment of the geoaccumulation index revealed that contamination levels of Cd and Hg were higher than those of other elements. In particular, Ni, Cd, Zn, and Hg were most likely to accumulate in soils near coal mining areas, while Cd and Hg tended to accumulate near coal chemical plants. Regarding non-carcinogenic risks, oral ingestion was the major pathway of exposure to potentially toxic elements in coal industry-associated soils, followed by dermal contact and inhalation. Tolerable non-carcinogenic risk of potentially toxic elements and relatively high carcinogenic risks of As were observed. Children were most vulnerable to non-carcinogenic risks, while the carcinogenic risks estimated for adult and children populations were similar. Accordingly, As should be designated as top candidates for priority control to protect human health in the vicinity of coal industry-associated areas. This study provides timely information for developing control and management strategies to reduce soil contamination by potentially toxic elements in different types of coal industrial areas.

The influence of polymorphisms of xenobiotic-metabolizing and DNA repair genes in DNA damage, telomere length and global DNA methylation evaluated in open-cast coal mining workers

Coal plants represent one of the main sources of environmental pollution due to the combustion process of this mineral and the consequent release of gases and particles which, in significant quantities, can lead to a potential risk to health and the environment. The susceptibility of individuals to the genotoxic effects of coal mining can be modulated by genetic variations in the xenobiotic detoxification and DNA repair processes. The aim of this study was to evaluate if xenobiotic metabolism polymorphism, base excision repair polymorphisms and non-homologous end joining repair polymorphism, could modify individual susceptibility to genomic instability and epigenetic alterations induced in workers by occupational exposure to coal. In this study, polymerase chain reaction was used to examine the polymorphic sites. The sample population comprising 70 coal mine workers and 71 workers non-exposed to coal. Our results demonstrated the effect of individual genotypes on different biomarkers evaluated. Significant decrease in % of global DNA methylation were observed in CYP1A1 Val/- exposed individuals compared to CYP1A1 Ile/Ile individuals. Coal workers who carried the XRCC4 Ile/Ile genotype showed decrease NBUD frequencies, while the XRCC4 Thr/- genotype was associated with decrease in Buccal micronucleus cells for the group not exposed. No influence of GSTM1 null, GSTT1 null, GSTP1 Ile105Val, hOGG1 Ser326Cys, XRCC1 Arg194Trp polymorphisms was observed. Thus, the current study reinforces the importance of considering the effect of metabolizing and repair variant genotypes on the individual susceptibility to incorporate DNA damage, as these processes act in a coordinated manner to determine the final response to coal exposure.

Micronucleus and other nuclear abnormalities in exfoliated cells of buccal mucosa of bats at different trophic levels

The micronucleus (MN) test in exfoliated cells of the buccal mucosa is a relatively non-invasive method for the monitoring of populations exposed to genotoxic risks. In this study, the MN test was used as bats conservation strategy. The highest frequencies of micronuclei were recorded in the frugivorous bats sampled in both urban and agricultural environments, as well as in insectivorous bats from the urban zone. Female of this group (insectivorous) presented higher frequency of MN when compared to males. Other guilds showed no difference in gender assessments in each environment, as well as in the correlation between weight and MN. In addition to micronuclei, a number of other types of nuclear abnormality were recorded, including binucleated cells and karyolysis in the frugivores from the agricultural environment. Binucleated cells were also relatively common in urban frugivores and insectivores, and karyolysis was common in insectivores. Nectarivorous bats did not exhibit a significant increase in any type of nuclear abnormality in either environment. In summary, study results indicate that buccal mucosa of bats is a sensitive site for detecting micronuclei and other nuclear abnormalities. However, more research is needed to indicate whether xenobiotic agents are affecting this cellular integrity.

Genetic damage in human populations at mining sites in the upper basin of the San Jorge River, Colombia

Contamination with mining wastes affects the environmental health and public, especially the human populations that live in these environments. The aim of this study was to evaluate the genotoxicity and levels of mercury (Hg) and arsenic (As) in blood samples from human populations exposed to mining activities in the upper basin of the San Jorge River. A total of 100 individuals participated in the study, 50 as an exposed group (Bocas de Ure = 15 individuals, Mina el Alacrán = 19 individuals, Torno Rojo = 16 individuals) and 50 individuals participated as the control group. Hg and As contents in blood samples were analyzed with atomic absorption spectrophotometry. A comet assay in peripheral blood lymphocytes and a micronucleus (MN) cytome assay (BMCyt) in exfoliated buccal cells were used to assess the effects of exposure to heavy metals on human communities located in mining areas. Higher concentrations of Hg and As were observed in human populations located in mining areas. The comet assay and BMCyt data revealed DNA damage and cell death in human communities located in mining areas. A positive association between blood arsenic and genetic damage was found. These data confirm the public health risk of the population near mining sites. Our findings suggest that populations that live at sites close to mining activities have high contents of heavy metals and genotoxic effects, representing a risk to human health.

Genotoxicological analyses of insectivorous bats (Mammalia: Chiroptera) in central Brazil: The oral epithelium as an indicator of environmental quality

The micronucleus (MN) test of the human buccal mucosa was developed more than 30 years ago, although this technique has only recently been applied to wild mammals. This paper presents a pioneering study in the genotoxicological evaluation of the exfoliated cells of the buccal mucosa of bats. The assay was applied to two insectivorous bat species (Noctilio albiventris and Pteronotus parnellii) sampled in riparian corridors located in the city of Palmas (capital of the Brazilian state of Tocantins), with the results being compared with those obtained for a third insectivorous species (Nyctinomops laticaudatus), which has established a colony under a road bridge in the same region. This colony represents one of the largest molossidae populations ever recorded in Brazil. A significantly higher frequency of micronuclei was recorded in this colony, as well as a number of other nuclear abnormalities, including binucleated cells, cells with condensed chromatin and karyolysis, in comparison with the bats from the riparian corridors, indicating that the bats from the bridge colony are more susceptible to genotoxic damage. Thus, it is demonstrated the importance of the biomarker (MN) for use in wild animals and allows to conclude that colony bats are more susceptible to genotoxic damages.

Geospatial analysis of residential proximity to open-pit coal mining areas in relation to micronuclei frequency, particulate matter concentration, and elemental enrichment factors

During coal surface mining, several activities such as drilling, blasting, loading, and transport produce large quantities of particulate matter (PM) that is directly emitted into the atmosphere. Occupational exposure to this PM has been associated with an increase of DNA damage, but there is a scarcity of data examining the impact of these industrial operations in cytogenetic endpoints frequency and cancer risk of potentially exposed surrounding populations. In this study, we used a Geographic Information Systems (GIS) approach and Inverse Distance Weighting (IDW) methods to perform a spatial and statistical analysis to explore whether exposure to PM_2.5 and PM₁₀ pollution, and additional factors, including the enrichment of the PM with inorganic elements, contribute to cytogenetic damage in residents living in proximity to an open-pit coal mining area. Results showed a spatial relationship between exposure to elevated concentrations of PM_2.5, PM₁₀ and micronuclei frequency in binucleated (MNBN) and mononucleated (MNMONO) cells. Active pits, disposal, and storage areas could be identified as the possible emission sources of combustion elements. Mining activities were also correlated with increased concentrations of highly enriched elements like S, Cu and Cr in the atmosphere, corroborating its role in the inorganic elements pollution around coal mines. Elements enriched in the PM_2.5 fraction contributed to increasing of MNBN but seems to be more related to increased MNMONO frequencies and DNA damage accumulated in vivo. The combined use of GIS and IDW methods could represent an important tool for monitoring potential cancer risk associated to dynamically distributed variables like the PM.

Evaluating the OGG1 rs1052133 and rs293795 polymorphisms in a sample of rural workers from Central Brazil population: a comparative approach with the 1000 Genomes Project

Brazilian population is one of the largest consumers of pesticides in the world, especially the Central Brazil population. Thus, the aim of this study was to evaluate the frequency of genotypes, alleles, haplotypes, and the linkage disequilibrium (DL) of the OGG1 gene in rural workers from Central Brazil, comparing with the populations of the 1000 genome. Three hundred thirty healthy individuals not related and randomly selected were included in this study. We obtained genomic DNA from peripheral blood lymphocytes. The 748-bp OGG1 gene was amplified by PCR and sequenced. Of the 330 individuals, 215 (65%) were males and 115 (35%) were females. There were no differences in the distribution of the rs1052133 and rs293795 with age and sexes. Haplotypes containing only conserved T/C alleles were the most common in our population. The frequency of the mutant alleles of rs1052133 and rs293795, in our population, was 20% and 30%, respectively, and it is noteworthy, worldwide, that mutant alleles are commonly associated to an increased risk for the development of cancer, specially due to direct or indirect contact to pesticides, as occurs in rural workers of Central Brazil population.

Mortality and morbidity in populations in the vicinity of coal mining: a systematic review

BACKGROUND

Evidence of the association of coal mining with health outcomes such as increased mortality and morbidity in the general population has been provided by epidemiological studies in the last 25 years. Given the diverse sources of data included to investigate different health outcomes in the exposed populations, the International Classification of Diseases (ICD) can be used as a single classification standard to compare the findings of studies conducted in different socioeconomic and geographic contexts. The ICD classifies diagnoses of diseases and other disorders as codes organized by categories and chapters.

OBJECTIVES

Identify the ICD codes found in studies of morbidity and/or mortality in populations resident or in proximity of coal mining and assess the methods of these studies conducting a systematic review.

METHODS

A systematic database search of PubMed, EMBASE and Scopus following the PRISMA protocol was conducted to assess epidemiological studies from 1990 to 2016. The health outcomes were mapped to ICD codes and classified by studies of morbidity and/or mortality, and the categories and chapters of the ICD.

RESULTS

Twenty-eight epidemiological studies with ecological design from the USA, Europe and China were included. The exposed populations had increased risk of mortality and/or morbidity by 78 ICD diagnosis categories and 9 groups of ICD categories in 10 chapters of the ICD: Neoplasms, diseases of the circulatory, respiratory and genitourinary systems, metabolic diseases, diseases of the eye and the skin, perinatal conditions, congenital and chromosomal abnormalities, and external causes of morbidity. Exposed populations had non-increased risk of 9 ICD diagnosis categories of diseases of the genitourinary system, and prostate cancer.

CONCLUSIONS

There is consistent evidence of the association of coal mining with a wide spectrum of diseases in populations resident or in proximity of the mining activities. The methods of the studies included in this review can be integrated with individual-level and longitudinal studies to provide further evidence of the exposure pathways linked to increased risk in the exposed populations.

Cytogenetic instability in populations with residential proximity to open-pit coal mine in Northern Colombia in relation to PM10 and PM2.5 levels

Epidemiological studies indicate that living in proximity to coal mines is correlated with numerous diseases including cancer, and that exposure to PM₁₀ and PM_2.5 components could be associated with this phenomenon. However, the understanding of the mechanisms by which PM exerts its adverse effects is still incomplete and comes mainly from studies in occupationally exposed populations. The aims of this study were to: (1) evaluate DNA damage in lymphocytes assessing the cytokinesis-block micronucleus cytome assay (CBMN-cyt) parameters; (2) identify aneugenic or clastogenic effects in lymphocytes of exposed populations using CREST immunostaining for micronuclei; (3) evaluate multi-elemental composition of atmospheric particulate matter; and (4) verify relation between the DNA damage and PM_2.5 and PM₁₀ levels around the mining area. Analysis revealed a significant increase in micronuclei frequency in binucleated (MNBN) and mononucleated (MNMONO) cells of individuals with residential proximity to open-pit coal mines compared to residents from non-mining areas. Correlation analysis demonstrated a highly significant association between PM_2.5 levels, MNBN frequencies and CREST+ micronuclei induction in exposed residents. These results suggest that PM_2.5 fraction generated in coal mining activities may induce whole chromosome loss (aneuploidy) preferentially, although there are also chromosome breaks. Analysis of the chemical composition of PM_2.5 by PIXE demonstrated that Si, S, K and Cr concentrations varied significantly between coal mining and reference areas. Enrichment factor values (EF) showed that S, Cr and Cu were highly enriched in the coal mining areas. Compared to reference area, mining regions had also higher concentrations of extractable organic matter (EOM) related to nonpolar and polar compounds. Our results demonstrate that PM_2.5 fraction represents the most important health risk for residents living near open-pit mines, underscoring the need for incorporation of ambient air standards based on PM_2.5 measures in coal mining areas.

Genotoxicity in Brazilian coal miners and its associated factors

The present study aims to evaluate the potential genotoxic and associated factors among coal miners, divided by degree of exposure. Blood and buccal smears were collected from 158 workers, who actively participate in different activities in coal mining, and 48 individuals living in the same city but do not have participation in coal mining activities (control group). The workers were divided into three different groups, according to the level of contact with coal extraction. A questionnaire intended to identify factors associated with DNA damage was performed in participants. The results regarding oral mucosa micronucleus test showed a significant difference ( p < 0.001) of the worker groups 1 and 2 in relation to the control group, where the group 1 has a higher degree of exposure to coal than group 2. For the lymphocyte micronucleus test and comet assay, there was no significant difference between the exposed groups and control group. There is an association between the outcome and the fact of living in the municipality of the mining company and the exposure to radiation in the last 12 months. Besides, the multivariate analysis showed an association of the tail moment with radiation exposure in the last 12 months. Thus, the findings of this study reveal genotoxicity in oral mucosa cells of workers exposed to coal and that workers with higher degree of contact with coal have a more pronounced response.

The micronucleus test for the oral mucosa: global trends and new questions

This study reviews global trends in the publication of papers on the micronucleus test of the exfoliated cells of the oral mucosa in mammals as an approach for environmental biomonitoring. This test has been widely used due to its precision for the detection of chromosome damage. Our temporal analysis showed a significant increase (p < 0.05) in the publication of papers on the oral mucosa over the past 33 years. Brazil was the country that published most papers (24% of the total), followed by India (16%), the USA (10%), Mexico (7%), and Turkey (6%). A further 30 countries contributed the other 37% of the papers. Overall, 99% of the micronucleus studies involved human subjects, and only 1% involved other mammals. As many wild mammals are subject to the same environmental pressures as humans, in particular chemical pollution, it seems likely that many species are equally susceptible to genotoxicogical damage. We emphasize the importance of applying this technique to the analysis of the oral mucosa of wild mammals, as well as the evaluation of its effectiveness, as observed in humans, and the expansion of the available approaches to the monitoring of environmental quality.