Peer Reviewed

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Field Survey of Health Perception and Complaints of Pennsylvania Residents in the Marcellus Shale Region

Documentation, Peer Reviewed, Public Health

Abstract

Pennsylvania Marcellus Shale region residents have reported medical symptoms they believe are related to nearby Unconventional Natural Gas Development (UNGD). Associations between medical symptoms and UNGD have been minimally explored. The objective of this descriptive study is to explore whether shale region Pennsylvania residents perceive UNGD as a health concern and whether they attribute health symptoms to UNGD exposures. A questionnaire was administered to adult volunteers with medical complaints in a primary-care medical office in a county where UNGD was present. Participants were asked whether they were concerned about health effects from UNGD, and whether they attributed current symptoms to UNGD or to some other environmental exposure. There were 72 respondents; 22% perceived UNGD as a health concern and 13% attributed medical symptoms to UNGD exposures. Overall, 42% attributed one or more of their medical symptoms to environmental causes, of which UNGD was the most frequent. A medical record review conducted on six participants who attributed their medical symptoms to UNGD revealed that only one of these records documented both the symptoms in question and the attribution to UNGD. The results of this pilot study suggest that there is substantial concern about adverse health effects of UNGD among Pennsylvania Marcellus Shale residents, and that these concerns may not be adequately represented in medical records. Further efforts to determine the relationship between UNGD and health are recommended in order to address community concerns.

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Environmental Public Health Dimensions of Shale and Tight Gas Development

Documentation, Peer Reviewed, Public Health

Abstract

Background: The United States has experienced a boom in natural gas production due to recent technological innovations that have enabled this resource to be produced from shale formations.
Objectives: This review discusses the body of evidence that focuses on exposure pathways to evaluate the potential environmental public health impacts of shale gas development. It highlights what is currently known and identifies data gaps and research limitations by addressing matters of toxicity, exposure pathways, air quality, and water quality.
Discussion: There is evidence of potential environmental public health risks associated with shale gas development. A number of studies suggest that shale gas development contributes to levels of ambient air concentrations known to be associated with increased risk of morbidity and mortality. Similarly, an increasing body of studies suggest water contamination risks exist through a variety of environmental pathways, most notably during wastewater transport and disposal and via poor zonal isolation of gases and fluids due to structural integrity impairment of cement in gas wells.
Conclusion: Despite a growing body of evidence, a number of data gaps persist. Most importantly, there is a need for more epidemiological studies to assess associations between risk factors, such as air and water pollution and health outcomes among populations living in close proximity to shale gas operations.

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Understanding exposure from natural gas drilling puts current air standards to the test

Air Pollution, Peer Reviewed

Abstract

Case study descriptions of acute onset of respiratory, neurologic, dermal, vascular, abdominal, and gastrointestinal sequelae near natural gas facilities contrast with a subset of emissions research, which suggests that there is limited risk posed by unconventional natural gas development (UNGD). An inspection of the pathophysiological effects of acute toxic actions reveals that current environmental monitoring protocols are incompatible with the goal of protecting the health of those living and working near UNGD activities. The intensity, frequency, and duration of exposures to toxic materials in air and water determine the health risks to individuals within a population. Currently, human health risks near UNGD sites are derived from average population risks without adequate attention to the processes of toxicity to the body. The objective of this paper is to illustrate that current methods of collecting emissions data, as well as the analyses of these data, are not sufficient for accurately assessing risks to individuals or protecting the health of those near UNGD sites. Focusing on air pollution impacts, we examined data from public sources and from the published literature. We compared the methods commonly used to evaluate health safety near UNGD sites with the information that would be reasonably needed to determine plausible outcomes of actual exposures. Such outcomes must be based on the pathophysiological effects of the agents present and the susceptibility of residents near these sites. Our study has several findings. First, current protocols used for assessing compliance with ambient air standards do not adequately determine the intensity, frequency or durations of the actual human exposures to the mixtures of toxic materials released regularly at UNGD sites. Second, the typically used periodic 24-h average measures can underestimate actual exposures by an order of magnitude. Third, reference standards are set in a form that inaccurately determines health risk because they do not fully consider the potential synergistic combinations of toxic air emissions. Finally, air dispersion modeling shows that local weather conditions are strong determinates of individual exposures. Appropriate estimation of safety requires nested protocols that measure real time exposures. New protocols are needed to provide 1) continuous measures of a surrogate compound to show periods of extreme exposure; 2) a continuous screening model based on local weather conditions to warn of periodic high exposures; and 3) comprehensive detection of chemical mixtures using canisters or other devices that capture the major components of the mixtures.

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Planning For Fracking on the Barnett Shale: Urban Air Pollution, Improving Health Based Regulation, and the Role of Local Governments

Air Pollution, Peer Reviewed, Public Health, Uncategorized

Abstract

In the last decade hydraulic fracturing for natural gas has exploded on the Barnett Shale in Texas. The region is now home to the most intensive hydraulic fracking and gas production activities ever undertaken in densely urbanized areas. Faced with minimal state and federal regulation, Texas cities are on the front line in the effort to figure out how best to balance industry, land use, and environmental concerns. Local governments in Texas, however, do not currently have the regulatory authority, capacity, or the information required to close the regulatory gap. Using the community experience on the Barnett Shale as a case study, this article focuses on the legal and regulatory framework governing air emissions and proposes changes to the current regulatory structure.
Under both the state and federal programs, the regulation of hazardous air emissions from gas operations is based largely on questions of cost and available technology. There is no comprehensive cumulative risk assessment to consider the potential impact to public health in urban areas. Drilling operations are being conducted in residential areas. Residents living in close proximity to gas operations on the Barnett Shale have voiced serious concerns for their health, which have yet to be comprehensively evaluated. Given the complexity of the science, and the dearth of clear, transparent, and enforceable standards, inadequate studies and limited statistical analysis have been allowed to provide potentially false assurances. The politically expedient bottom line dominates with little attention paid to the quality of the science or the adequacy of the standards.
Determining and applying comprehensive health-based standards for hazardous air pollutants has been largely abandoned at the federal level given uncertainties in the science, difficulties of determining and measuring “safe” levels of toxic pollutants, and the potential for economic disruption. Neither the state nor the federal government has set enforceable ambient standards for hazardous air pollutants. Identifying cumulative air pollution problems that may occur in urban areas, the State of California has called upon local governments to identify “hot spots” and to consider air quality issues in their planning and zoning actions. In Texas, however, preemption discussions dominate the analysis. Any local government regulation that might provide protection from toxic air emissions otherwise regulated by the State must be justified by some other public purpose.
Texas should consider authorizing and encouraging local level air quality planning for industrial activities, similar to what California has done. Care should be taken to separate these facilities from sensitive receptors and “hot spots” that may already be burdened with excessive hazardous air emissions. Given the difficulty of the task, there is also an important role for the state and federal governments in working to establish ambient standards for hazardous air pollutants, as well as standards for health based assessment and public communication. The uncertainty inherent in any of these standards should be made clear and accessible to local governments so that it may be considered in making appropriate and protective land use decisions. Texas should consider allowing local governments to have the power to establish ambient air quality standards, emissions limitations, monitoring, reporting, and offsets for hazardous air pollutants, following the model applied to conventional air pollutants pursuant to the federal program.

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Oil and gas wells and their integrity: Implications for shale and unconventional resource exploitation*

Peer Reviewed

Abstract

Data from around the world (Australia, Austria, Bahrain, Brazil, Canada, the Netherlands, Poland, the UK and the USA) show that more than four million onshore hydrocarbon wells have been drilled globally. Here we assess all the reliable datasets (25) on well barrier and integrity failure in the published literature and online. These datasets include production, injection, idle and abandoned wells, both onshore and offshore, exploiting both conventional and unconventional reservoirs. The datasets vary considerably in terms of the number of wells examined, their age and their designs. Therefore the percentage of wells that have had some form of well barrier or integrity failure is highly variable (1.9%–75%). Of the 8030 wells targeting the Marcellus shale inspected in Pennsylvania between 2005 and 2013, 6.3% of these have been reported to the authorities for infringements related to well barrier or integrity failure. In a separate study of 3533 Pennsylvanian wells monitored between 2008 and 2011, there were 85 examples of cement or casing failures, 4 blowouts and 2 examples of gas venting. In the UK, 2152 hydrocarbon wells were drilled onshore between 1902 and 2013 mainly targeting conventional reservoirs. UK regulations, like those of other jurisdictions, include reclamation of the well site after well abandonment. As such, there is no visible evidence of 65.2% of these well sites on the land surface today and monitoring is not carried out. The ownership of up to 53% of wells in the UK is unclear; we estimate that between 50 and 100 are orphaned. Of 143 active UK wells that were producing at the end of 2000, one has evidence of a well integrity failure.

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*Note: Funding includes industry sources.


Highly Elevated Atmospheric Levels of Volatile Organic Compounds in the Uintah Basin, Utah

Air Pollution, Peer Reviewed

Abstract

Oil and natural gas production in the Western United States has grown rapidly in recent years, and with this industrial expansion, growing environmental concerns have arisen regarding impacts on water supplies and air quality. Recent studies have revealed highly enhanced atmospheric levels of volatile organic compounds (VOC) from primary emissions in regions of heavy oil and gas development and associated rapid photochemical production of ozone during winter. Here, we present surface and vertical profile observations of VOC from the Uintah Basin Winter Ozone Studies conducted in January – February of 2012 and 2013. These measurements identify highly elevated levels of atmospheric alkane hydrocarbons with enhancement rates of C2 – C6 non-methane hydrocarbon (NMHC) mean mole fractions during temperature inversion events in 2013at 200-300 times above the regional and seasonal background. Elevated atmospheric NMHC mole fractions coincided with build-up of ambient 1-hour ozone to levels exceeding 150 ppbv (parts per billion by volume). The total annual mass flux of C2-C7 VOC was estimated at 194 ± 56 x 106 kg yr-1, equivalent to the annual VOC emissions of a fleet of ~100 million automobiles. Total annual fugitive emission of the aromatic compounds benzene and toluene, considered air toxics, were estimated at 1.6 ± 0.4 x 106 and 2.0 ± 0.5 x 106 kg yr-1, respectively. These observations reveal a strong causal link between oil and gas emissions, accumulation of air toxics, and significant surface production in the atmospheric surface layer.

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PSE Study Citation Database on Shale Gas & Tight Oil Development

Peer Reviewed

This citation database provides bibliographic information, abstracts, and links to many of the vetted scientific papers housed in the PSE Healthy Energy Library, as well as other peer-reviewed journal articles. This database is a near exhaustive and evolving list of the peer-reviewed literature that directly pertains to shale gas and tight oil development. This literature is organized into twelve different categories, including air quality, water quality, climate, public health, and regulations. PSE Healthy Energy does not necessarily support the methods and the findings of the studies included in this database.

See more at: http://psehealthyenergy.org/site/view/1180


Potential Public Health Hazards, Exposures and Health Effects from Unconventional Natural Gas Development

Peer Reviewed, Public Health

Abstract

The rapid increase in unconventional natural gas (UNG) development in the United States during the past decade has brought wells and related infrastructure closer to population centers. This review evaluates risks to public health from chemical and nonchemical stressors associated with UNG, describes likely exposure pathways and potential health effects, and identifies major uncertainties to address with future research. The most important occupational stressors include mortality, exposure to hazardous materials and increased risk of industrial accidents. For communities near development and production sites the major stressors are air pollutants, ground and surface water contamination, truck traffic and noise pollution, accidents and malfunctions, and psychosocial stress associated with community change. Despite broad public concern, no comprehensive population-based studies of the public health effects of UNG operations exist. Major uncertainties are the unknown frequency and duration of human exposure, future extent of development, potential emission control and mitigation strategies, and a paucity of baseline data to enable substantive before and after comparisons for affected populations and environmental media. Overall, the current literature suggests that research needs to address these uncertainties before we can reasonably quantify the likelihood of occurrence or magnitude of adverse health effects associated with UNG production in workers and communities.

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Birth Outcomes and Maternal Residential Proximity to Natural Gas Development in Rural Colorado

Children's Health, Peer Reviewed, Public Health

Abstract

Background: Birth defects are a leading cause of neonatal mortality. Natural gas development (NGD) emits several potential teratogens and US production is expanding.
Objectives: We examined associations between maternal residential proximity to NGD and birth outcomes in a retrospective cohort study of 124,842 births between 1996 and 2009 in rural Colorado.
Methods: We calculated inverse distance weighted natural gas well counts within a 10-mile radius of maternal residence to estimate maternal exposure to NGD. Logistic regression, adjusted for maternal and infant covariates, was used to estimate associations with exposure tertiles for congenital heart defects (CHDs), neural tube defects (NTDs), oral clefts, preterm birth, and term low birth weight. The Association with term birth weight was investigated using multiple linear regression.
Results: Prevalence of CHDs increased with exposure tertile, with an odds ratio (OR) of 1.3 for the highest tertile (95% CI: 1.2, 1.5) and NTD prevalence was associated with the highest tertile of exposure (OR = 2.0, 95% CI: 1.0, 3.9, based on 59 cases), compared to no gas wells within a 10-mile radius. Exposure was negatively associated with preterm birth and positively associated with fetal growth, though the magnitude of association was small. No association was found between exposure and oral clefts.
Conclusions: In this large cohort, we observed an association between density and proximity of natural gas wells within a 10-mile radius of maternal residence and prevalence of CHDs and possibly NTDs. Greater specificity in exposure estimates are needed to further explore these associations.

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Estrogen and Androgen Receptor Activities of Hydraulic Fracturing Chemicals and Surface and Ground Water in a Drilling-Dense Region

Peer Reviewed, Public Health

Abstract

The rapid rise in natural gas extraction utilizing hydraulic fracturing increases the potential for contamination of surface and ground water from chemicals used throughout the process. Hundreds of products containing more than 750 chemicals and components are potentially used throughout the extraction process, including over one hundred known or suspected endocrine disrupting chemicals. We hypothesized that a selected subset of chemicals used in natural gas drilling operations and also surface and ground water samples collected in a drilling-dense region of Garfield County, CO would exhibit estrogen and androgen receptor activities. Water samples were collected, solid-phase extracted, and measured for estrogen and androgen receptor activities using reporter gene assays in human cell lines. Of the 39 unique water samples, 89%, 41%, 12%, and 46% exhibited estrogenic, anti-estrogenic, androgenic, and anti-androgenic activities, respectively. Testing of a subset of natural gas drilling chemicals revealed novel anti-estrogenic, novel anti-androgenic, and limited estrogenic activities. The Colorado River, the drainage basin for this region, exhibited moderate levels of estrogenic, anti-estrogenic, and anti-androgenic activities, suggesting that higher localized activity at sites with known natural gas related spills surrounding the river might be contributing to the multiple receptor activities observed in this water source. The majority of water samples collected from sites in a drilling-dense region of Colorado exhibited more estrogenic, anti-estrogenic, or anti-androgenic activities than reference sites with limited nearby drilling operations. Our data suggest that natural gas drilling operations may result in elevated EDC activity in surface and ground water.

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The role of ethics in shale gas policies

Peer Reviewed, Public Health

Abstract

The United States has experienced a boom in natural gas production due to recent technological innovations that have enabled natural gas to be produced from unconventional sources, such as shale. There has been much discussion about the costs and benefits of developing shale gas among scientists, policy makers, and the general public. The debate has typically revolved around potential gains in economics, employment, energy independence, and national security as well as potential harms to the environment, the climate, and public health. In the face of scientific uncertainty, national and international governments must make decisions on how to proceed. So far, the results have been varied, with some governments banning the process, others enacting moratoria until it is better understood, and others explicitly sanctioning shale gas development. These policies reflect legislature’s preferences to avoid false negative errors or false positive ones. Here we argue that policy makers have a prima facie duty to minimize false negatives based on three considerations: (1) protection from serious harm generally takes precedence over the enhancement of welfare; (2) minimizing false negatives in this case is more respectful to people’s autonomy; and (3) alternative solutions exist that may provide many of the same benefits while minimizing many of the harms.

Air quality in the Industrial Heartland of Alberta, Canada and potential impacts on human health

Air Pollution, Peer Reviewed, Public Health

Abstract

The “Industrial Heartland” of Alberta is Canada’s largest hydrocarbon processing center, with more than 40 major chemical, petrochemical, and oil and gas facilities. Emissions from these industries affect local signair quality and human health. This paper characterizes ambient levels of 77 volatile organic compounds sign(VOCs) in the region using high-precision measurements collected in summer 2010. Remarkably strong enhancements of 43 VOCs were detected, and concentrations in the industrial plumes were often similar to or even higher than levels measured in some of the world’s largest cities and industrial regions. For example maximum levels of propene and i-pentane exceeded 100 ppbv, and 1,3-butadiene, a known carcinogen, reached 27 ppbv. Major VOC sources included propene fractionation, diluent separation and bitumen processing. Emissions of the measured VOCs increased the hydroxyl radical reactivity (kOH), a measure of the potential to form downwind ozone, from 3.4 s–1 in background air to 62 s–1 in the most concentrated plumes. The plume value was comparable to polluted megacity values, and acetaldehyde, propene and 1,3-butadiene contributed over half of the plume kOH. Based on a 13-year record (1994 e2006) at the county level, the incidence of male hematopoietic cancers (leukemia and non-Hodgkin lymphoma) was higher in communities closest to the Industrial Heartland compared to neighboring counties. While a causal association between these cancers and exposure to industrial emissions cannot be confirmed, this pattern and the elevated VOC levels warrant actions to reduce emissions of known carcinogens, including benzene and 1,3-butadiene.

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An Evaluation of Water Quality in Private Drinking Water Wells Near Natural Gas Extraction Sites in the Barnett Shale Formation

Peer Reviewed, Water Contamination

Abstract

Natural gas has become a leading source of alternative energy with the advent of techniques to economically extract gas reserves from deep shale formations. Here, we present an assessment of private well water quality in aquifers overlying the Barnett Shale formation of North Texas. We evaluated samples from 100 private drinking water wells using analytical chemistry techniques. Analyses revealed that arsenic, selenium, strontium and total dissolved solids (TDS) exceeded the Environmental Protection Agency’s Drinking Water Maximum Contaminant Limit (MCL) in some samples from private water wells located within 3 km of active natural gas wells. Lower levels of arsenic, selenium, strontium, and barium were detected at reference sites outside the Barnett Shale region as well as sites within the Barnett Shale region located more than 3 km from active natural gas wells. Methanol and ethanol were also detected in 29% of samples. Samples exceeding MCL levels were randomly distributed within areas of active natural gas extraction, and the spatial patterns in our data suggest that elevated constituent levels could be due to a variety of factors including mobilization of natural constituents, hydrogeochemical changes from lowering of the water table, or industrial accidents such as faulty gas well casings.

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Challenges of Unconventional Shale Gas Development: So What’s the Rush?

Peer Reviewed, Public Health

Abstract

The article discusses unconventional shale gas development (UGD) as of July 2013, focusing on U.S. natural gas production and the impact of UGD on energy utilization in America. Funding by the U.S. Department of Energy for shale gas extraction research and development is mentioned, along with water pollution and the direct health and environmental risks associated with toxicology and safety issues. Several American statutes are mentioned, including the Toxic Substances Control Act.

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Differing Opinions about Natural Gas Drilling in Two Adjacent Counties with Different Levels of Drilling Activity

Peer Reviewed, Public Health

Abstract

The pace of development of shale gas plays varies greatly among US states and globally. Through analysis of telephone survey responses, we explore support for natural gas drilling in residents of Washington County (WC), PA (n=502) vs. residents of Allegheny County (AC), PA (n=799). WC has had intense Marcellus Shale (MS) drilling activity, in comparison to adjacent AC, which has had little drilling activity. WC residents are marginally more supportive of MS drilling than are AC residents (p=0.0768). Residents of WC are more likely to perceive MS as an economic opportunity than are AC residents (p=0.0015); to be in a family that has signed a MS lease (p<0.0001); to follow the MS issue closely (p=0.0003); to get MS information from neighbors, friends, and relatives (p<0.0001); and are marginally less likely to perceive MS as an environmental threat (p=0.1090). WC leaseholders are significantly more supportive of MS drilling than WC non-leaseholders and AC non-leaseholders (p=0.0024). Mediation analyses show that county-based differences in support of MS drilling are due to WC residents seeing more of an economic opportunity in the MS and their greater likelihood of having a family-held lease.

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Assessment and longitudinal analysis of health impacts and stressors perceived to result from unconventional shale gas development in the Marcellus Shale region

Peer Reviewed, Public Health

Abstract

Introduction: Concerns for health and social impacts have arisen as a result of Marcellus Shale unconventional natural gas development. Our goal was to document the self-reported health impacts and mental and physical health stressors perceived to result from Marcellus Shale development.
Methods: Two sets of interviews were conducted with a convenience sample of community members living proximal to Marcellus Shale development, session 1 March‐September 2010 (n = 33) and session 2 January‐April 2012 (n = 20). Symptoms of health impacts and sources of psychological stress were coded. Symptom and stressor counts were quantified for each interview. The counts for each participant were compared longitudinally.
Results: Participants attributed 59 unique health impacts and 13 stressors to Marcellus Shale development. Stress was the most frequently-reported symptom. Over time, perceived health impacts increased (P = 0·042), while stressors remained constant (P = 0·855).
Discussion: Exposure-based epidemiological studies are needed to address identified health impacts and those that may develop as unconventional natural gas extraction continues. Many of the stressors can be addressed immediately.

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Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction

Peer Reviewed, Water Contamination

Abstract

Horizontal drilling and hydraulic fracturing are transforming energy production, but their potential environmental effects remain controversial. We analyzed 141 drinking water wells across the Appalachian Plateaus physiographic province of northeastern Pennsylvania, examining natural gas concentrations and isotopic signatures with proximity to shale gas wells. Methane was detected in 82% of drinking water samples, with average concentrations six times higher for homes <1 km from natural gas wells (P = 0.0006). Ethane was 23 times higher in homes <1 km from gas wells (P = 0.0013); propane was detected in 10 water wells, all within approximately 1 km distance (P = 0.01). Of three factors previously proposed to influence gas concentrations in shallow groundwater (distances to gas wells, valley bottoms, and the Appalachian Structural Front, a proxy for tectonic deformation), distance to gas wells was highly significant for methane concentrations (P = 0.007; multiple regression), whereas distances to valley bottoms and the Appalachian Structural Front were not significant (P = 0.27 and P = 0.11, respectively). Distance to gas wells was also the most significant factor for Pearson and Spearman correlation analyses (P < 0.01). For ethane concentrations, distance to gas wells was the only statistically significant factor (P < 0.005). Isotopic signatures (δ13C-CH4, δ13C-C2H6, and δ2H-CH4), hydrocarbon ratios (methane to ethane and propane), and the ratio of the noble gas 4He to CH4 in groundwater were characteristic of a thermally postmature Marcellus-like source in some cases. Overall, our data suggest that some homeowners living <1 km from gas wells have drinking water contaminated with stray gases.

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Exposure to Chemicals and Radiation During Childhood and Risk for Cancer Later in Life

Peer Reviewed, Public Health

Abstract

Purpose: Many chemical carcinogens are in food, water, air, household products, and personal care products. Although genetic susceptibility is an important factor in how an individual responds to exposure to a carcinogen, heritable genetic factors alone account for only a minor portion of cancer rates.
Methods: We review the evidence that early life exposure to carcinogenic chemicals and ionizing radiation results in elevations in cancer later in life.
Results: Because cells are rapidly dividing and organ systems are developing during childhood and adolescence, exposure to carcinogens during these early life stages is a major risk factor for cancer later in life. Because young people have many expected years of life, the clinical manifestations of cancers caused by carcinogens have more time in which to develop during characteristically long latency periods. Many chemical carcinogens persist in the body for decades and increase risk for all types of cancers. Carcinogens may act via mutagenic, nonmutagenic, or epigenetic mechanisms and may also result from disruption of endocrine systems. The problem is magnified by the fact that many chemical carcinogens have become an integral part of our food and water supply and are in air and the general environment.
Conclusions: The early life onset of a lifelong exposure to mixtures of multiple environmental chemical carcinogens and radiation contributes significantly to the etiology of cancer in later life.

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Traffic-Related Air Pollution, Particulate Matter, and Autism

Air Pollution, Peer Reviewed

Abstract

Context: Autism is a heterogeneous disorder with genetic and environmental factors likely contributing to its origins. Examination of hazardous pollutants has suggested the importance of air toxics in the etiology of autism, yet little research has examined its association with local levels of air pollution using residence-specific exposure assignments.
Objective: To examine the relationship between traffic-related air pollution, air quality, and autism.
Design: This population-based case-control study includes data obtained from children with autism and control children with typical development who were enrolled in the Childhood Autism Risks from Genetics and the Environment study in California. The mother’s address from the birth certificate and addresses reported from a residential history questionnaire were used to estimate exposure for each trimester of pregnancy and first year of life. Traffic-related air pollution was assigned to each location using a line-source air-quality dispersion model. Regional air pollutant measures were based on the Environmental Protection Agency’s Air Quality System data. Logistic regression models compared estimated and measured pollutant levels for children with autism and for control children with typical development.
Setting: Case-control study from California.
Participants: A total of 279 children with autism and a total of 245 control children with typical development.
Main Outcome Measures: Crude and multivariable adjusted odds ratios (AORs) for autism.
Results: Children with autism were more likely to live at residences that had the highest quartile of exposure to traffic-related air pollution, during gestation (AOR, 1.98 [95% CI, 1.20-3.31]) and during the first year of life (AOR, 3.10 [95% CI, 1.76-5.57]), compared with control children. Regional exposure measures of nitrogen dioxide and particulate matter less than 2.5 and 10 μm in diameter (PM2.5 and PM10) were also associated with autism during gestation (exposure to nitrogen dioxide: AOR, 1.81 [95% CI, 1.37-3.09]; exposure to PM2.5: AOR, 2.08 [95% CI, 1.93-2.25]; exposure to PM10: AOR, 2.17 [95% CI, 1.49-3.16) and during the first year of life (exposure to nitrogen dioxide: AOR, 2.06 [95% CI, 1.37-3.09]; exposure to PM2.5: AOR, 2.12 [95% CI, 1.45-3.10]; exposure to PM10: AOR, 2.14 [95% CI, 1.46-3.12]). All regional pollutant estimates were scaled to twice the standard deviation of the distribution for all pregnancy estimates.
Conclusions: Exposure to traffic-related air pollution, nitrogen dioxide, PM2.5, and PM10 during pregnancy and during the first year of life was associated with autism. Further epidemiological and toxicological examinations of likely biological pathways will help determine whether these associations are causal.

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Unconventional Natural Gas Development and Infant Health: Evidence from Pennsylvania (Work in Progress)

Children's Health, Public Health, Reports

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