Are residents of mountain-top mining counties more likely to have infants with birth defects? The West Virginia experience

Multiple exposure pathways and health risk assessment of potentially harmful elements for children and adults living in a coal region in Brazil

Energy generated by coal can contaminate the environment by releasing toxic elements, including metals. The human health risk assessment (HHRA) associated with geographic information system (GIS) tools can assist the management of contaminated areas, such as coal mining areas. The objective of the study was to carry out the assessment and spatialization of the risk to human health of potentially hazards elements (PHEs) in the soil for children and adults, from multiple exposure routes (oral, inhalation and dermal) in the Candiota mines, largest coal mining region of Brazil. The non-carcinogenic risks (HQ) of PHEs (Cu, Pb, Zn, Ni, Cr, Fe, Mn, Cd, As and Se) and carcinogenic risks of As were estimated and spatialized. The results revealed a risk for children exposure to Mn, with greatest contribution through dermal route. Mn (HQ_derm 72.41-96.09% and HQ_inh 40.84-82.52%) and Fe (HQ_o 43.90-81.44%) were the metals with greatest contribution to human health risk among studied population. As did not present carinogenic risk to adults. The spatial distribution of non-carcinogenic risk showed that Cr, As, Fe, Pb, Ni, Zn and Cu have higher HInc close to the coal mining areas, while Mn, Se and Cd have the highest HInc values in surrounding municipalities (Pinheiro Machado; Pedras Altas and Hulha Negra). The use of HHRA associated with GIS tools provides important elements for decision-making in the management of contaminated sites, indicating chemical elements, locations, routes of exposure and priority target populations.

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.

Human health risk assessment of metals and anions in surface water from a mineral coal region in Brazil

Coal mining releases high concentration elements to the environment, which can be deposited in surface water, causing several human health problems. Candiota mine in the south of Brazil is the largest coal reserves in the country, representing approximately 40% of total national coal reserves. Therefore, the present study aimed to estimate the chronic daily dose and the non-carcinogenic risk index for metals and anions in surface waters of Candiota Region, using the USEPA protocols for Human Health Risk Assessment. A total of eight water samples were collected over a distance of up to 15 km from the emission sources of the thermal power generation companies, then the Chronic Daily Intake (CDI), Hazard Quotient (HQ), Hazard Index (HI), and sum of Hazard Index (ΣHI) were calculated. All the elements and anions evaluated showed natural concentrations for continental fresh waters according to Brazilian legislation, except Pb. Individually, none of the metals Pb, As, Cd, Ni, and Se or anions F^- and NO₃^- showed an HI value greater than 1. However, the sum of HI (ΣHI) (five metals and two anions) by sample point showed values close to 1, for one of the eight points analyzed. Pb and Fe were the elements that most contribute to the risk values in the sample points of the study area. Although, there is no human health risk in this scenario, this investigation highlight priority elements to future investigations in coal mine areas. In the current region, Pb and F^- as priority elements for future studies.

Maternal, neonatal and socio-economic factors associated with intellectual development among children from a coal mining region in Brazil

Coal is the most aggressive energy sources in the environment. Several adverse outcomes on children's health exposure to coal pollutants have been reported. Pollutants from coal power plants adversely affect the intellectual development and capacity. The present study aimed to evaluate the intellectual development and associated factors among children living a city under the direct influence (DI) and six neighboring municipalities under the indirect influence (II) of coal mining activity in the largest coal reserve of Brazil. A structured questionnaire was completed by the child's guardian, and Raven's Progressive Color Matrices were administered to each child to assess intellectual development. A total of 778 children participated. In general, no significant difference was observed between the two cities. The DI city had better socioeconomic conditions than the II municipalities according to family income (< 0.001). The prevalence of children who were intellectually below average or with intellectual disabilities was 22.9%, and there was no significant difference (p > 0.05) between municipalities. In both unadjusted and adjusted analyses, intellectual development was associated with maternal age, marital situation and maternal education level, birth weight, breast feeding, frequent children's daycare, paternal participation in children's care and child growth. Living in the DI area was not associated with intellectual disability. The results suggest that socioeconomic conditions and maternal and neonatal outcomes are more important than environmental factors for intellectual development of children living in a coal mining area.

Surface mining and low birth weight in central appalachia

BACKGROUND

Surface mining has become a significant method of coal mining in the Central Appalachian region of the eastern United States alongside the traditional underground mining. Concerns have been raised about the health effects of this surface mining, particularly mountaintop removal mining where coal is mined upon steep mountaintops by removing the mountaintop through clearcutting forests and explosives.

METHODS

We used a control group design with a pretest and a posttest to assess the associations of surface mining in Central Appalachia with low birth weight and other adverse birth outcomes. The pretest period is 1977-1989, a period of low surface mining activity. We consider three posttest periods: 1990-1998, 1999-2011 and 2012-2017, with 1999-2011 as the primary analysis and the other periods as secondary analyses. Surface mining in Central Appalachia increased after 1989, partly resulting from the Clean Air Act Amendments of 1990 which made surface mining in Appalachia more financially attractive. For the primary analysis, we fit a logistic regression model of the primary outcome (low birth weight, <2500 g) on dummy variables for county and year; individual level maternal/infant covariates (maternal race, maternal age, infant sex and whether birth was a multiple birth); and the amount of surface mining during the year of the birth in the maternal county of residence.

RESULTS

Our analysis sample consisted of 783,328 infants -- 482,284 infants born from 1977 to 2017 to women residing in substantial surface mining activity counties and 301,044 infants born from 1977 to 2017 to women residing in matched control counties. Compared to the pre-period of low surface mining from 1977 to 1989, for the primary analysis posttest period of 1999-2011, there was an estimated relative increase in low birth weight in surface mining counties compared to matched control counties that was not statistically significant (odds ratio for a 5 percentage point increase in area disturbed by surface mining: 1.07, 95% confidence interval (0.96, 1.20), p-value: .22). For the secondary analysis posttest period of 1990-1998, there was no increase (odds ratio: 0.91, 95% confidence interval: (0.74, 1.13), p-value: .41). For the secondary analysis posttest period of 2012-2017, there was a statistically significant relative increase (odds ratio: 1.28, 95% confidence interval: (1.08, 1.50), p-value: .004). Qualitatively similar results were found for the outcomes of very low birth weight, preterm birth and small-for-gestational age.

CONCLUSIONS

We examined the hypothesis that surface mining activity in Central Appalachia contributes to low birth weight using an observational study. We found evidence in secondary analyses that surface mining was associated with low birth weight in the 2012-2017 time period and potentially beginning in the early to mid 2000's. Evidence for an association was not found prior to 2000. A potential explanation for this pattern of association is that surface mining caused an increase in low birth weight but its onset was delayed. Future research is needed to clarify the findings and if replicated, identify the mechanism necessary to mitigate the impacts of mining on adverse birth outcomes.

Multiple exposure pathways and health risk assessment of selenium for children in a coal mining area

Selenium (Se) presents a dual role to human body, harmful or beneficial, depending on its concentration. The exposure to this element has been associated to coal mining. Health risk assessment allows estimating and evaluating the risks that environmental hazards pose to vulnerable groups of populations. The present study aimed to analyze the risk of exposure to Se through multiple exposure pathways in children living in Candiota city, where the largest coal reserve of Brazil is located. Data from previous environmental (air, soil, drinking water, and food) and population parameters (age, weight, and food intake) were used to assess the health risk, which was calculated with real values (extracted from the population) and fixed reference values, based on the USEPA recommendation. Most of the children had low health risk (HQ < 1); however, in the most conservative scenarios (higher Se values in the different matrices), there was a high health risk in both scenarios, using population data or the USEPA parameters. The mean HQ using reference values was twice higher than using real values. Se content in air, soil, and drinking water did not represent important average daily dose in both scenarios. While, food intake was a main source of Se exposure, contributing with 96.9% of total Se intake. The findings of this study reinforce the importance of food intake for exposure to Se and the difference between HQs using population measures and fixed parameters of the USEPA highlights the need for adaptations to local scenarios for a better dimensioning of toxicological risk management actions.

Rural and urban differences in prenatal exposure to essential and toxic elements

Excess or inadequate levels of inorganic ions may induce significant acute and long-term irreversible dysfunction in humans. The fetus and placenta are particularly vulnerable to toxins due to the immaturity of the blood-brain barrier and diminished biotransformation enzymatic activity. A comparative cross-sectional study was conducted on 172 pregnant women, 79 rural, and 93 urban. Umbilical cord blood was collected at the time of delivery and analyzed for 20 inorganic elements. Significant differences were found between urban and rural samples for two elements where copper (Cu) and molybdenum (Mo) were higher in urban samples. No marked differences between groups occurred for: arsenic, barium, cadmium, calcium, cobalt, lead, lithium, magnesium, manganese, mercury, selenium, strontium, or zinc. All samples were devoid of platinum, silver, thallium or uranium. Data demonstrated significant differences in urban and rural prenatal exposure to Cu and Mo. Further study is needed to determine if there is a causal link between neonatal outcomes and prenatal exposure to these elements.

Shale gas development and infant health: Evidence from Pennsylvania

This research exploits the introduction of shale gas wells in Pennsylvania in response to growing controversy around the drilling method of hydraulic fracturing. Using detailed location data on maternal addresses and GIS coordinates of gas wells, this study examines singleton births to mothers residing close to a shale gas well from 2003 to 2010 in Pennsylvania. The introduction of drilling increased low birth weight and decreased term birth weight on average among mothers living within 2.5 km of a well compared to mothers living within 2.5 km of a permitted well. Adverse effects were also detected using measures such as small for gestational age and APGAR scores, while no effects on gestation periods were found. In the intensive margin, an additional well is associated with a 7 percent increase in low birth weight, a 5 g reduction in term birth weight and a 3 percent increase in premature birth. These results are robust to other measures of infant health, many changes in specification and falsification tests. These findings suggest that shale gas development poses significant risks to human health.

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.

Embryonic exposure to an aqueous coal dust extract results in gene expression alterations associated with the development and function of connective tissue and the hematological system, immunological and inflammatory disease, and cancer in zebrafish

Coal mining is one of the economic activities with the greatest impact on environmental quality. At all stages contaminants are released as particulates such as coal dust. The first aim of this study was to obtain an aqueous coal dust extract and characterize its composition in terms of trace elements by ICP-MS. In addition, the developmental toxicity of the aqueous coal extract was evaluated using zebrafish (Danio rerio) after exposure to different concentrations (0-1000 ppm; μg mL^-1) to establish acute toxicity, morphology and transcriptome changes. Trace elements within the aqueous coal dust extract present at the highest concentrations (>10 ppb) included Sr, Zn, Ba, As, Cu and Se. In addition, Cd and Pb were found in lower concentrations. No significant difference in mortality was observed (p > 0.05), but a delay in hatching was found at 0.1 and 1000 ppm (p < 0.05). No significant differences in morphological characteristics were observed in any of the treatment groups (p > 0.05). Transcriptomic results of zebrafish larvae revealed alterations in 77, 61 and 1376 genes in the 1, 10, and 100 ppm groups, respectively. Gene ontology analysis identified gene alterations associated with the development and function of connective tissue and the hematological system, as well as pathways associated with apoptosis, the cell cycle, transcription, and oxidative stress including the MAPK signaling pathway. In addition, altered genes were associated with cancer; connective tissue, muscular, and skeletal disorders; and immunological and inflammatory diseases. Overall, this is the first study to characterize gene expression alterations in response to developmental exposure to aqueous coal dust residue from coal mining with transcriptome results signifying functions and systems to target in future studies.

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.