Volume 33, Issue 1

Heavy metals (arsenic and manganese), particulate matter (PM), benzene, toluene, ethylbenzene, xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs) and endocrine disrupting chemicals (EDCs) have been linked to significant neurodevelopmental health problems in infants, children and young adults. These substances are widely used in, or become byproducts of unconventional oil and natural gas (UOG) development and operations. Every stage of the UOG lifecycle, from well construction to extraction, operations, transportation and distribution can lead to air and water contamination. Residents near UOG operations can suffer from increased exposure to elevated concentrations of air and water pollutants. Here we focus on five air and water pollutants that have been associated with potentially permanent learning and neuropsychological deficits, neurodevelopmental disorders and neurological birth defects. Given the profound sensitivity of the developing brain and central nervous system, it is reasonable to conclude that young children who experience frequent exposure to these pollutants are at particularly high risk for chronic neurological diseases. More research is needed to understand the extent of these concerns in the context of UOG, but since UOG development has expanded rapidly in recent years, the need for public health prevention techniques, well-designed studies and stronger state and national regulatory standards is becoming increasingly apparent.

Zika is a vector-borne viral disease transmitted to humans primarily by Aedes aegypti mosquitoes. The increased climate instability has contributed to the emergence of infections carried by mosquitoes like dengue, chikungunya and zika. While infection with the zika virus is not new, the recent epidemic of microcephaly in Brazil and other countries in South America resulting from the infection of pregnant women with the zika virus raise a number of serious public health concerns. These include the question of how climate change affects the range of zika vectors, what can we do to shorten the length of mosquito season, how and why the symptoms of zika infection have changed and what can be done to reduce the burden of human disease from this infection? Another important question that needs to be answered is what are the factors that caused the zika virus to leave the non-human primates and/or other mammals and invade the human population?

Objective: This paper primarily aimed to review articles which specifically quantified the risk of electronic cigarette’s (e-cigarette) usage via the health risk assessment (HRA) approach. Methods: Systematic literature searches were conducted using PubMed search engine databases. Search terms such as “electronic cigarette”, “e-cigarette”, “electronic nicotine delivery systems”, “electronic cigarette liquid”, “electronic cigarette vapors”, and “health risk assessment” were used to identify the relevant articles to be included in this review. To enable comparison, hazard quotient (HQ) and lifetime cancer risk (LCR) for the chemicals measured in the selected articles were calculated for three of the articles using the formula: [1] HQ=average daily dose (ADD)/reference dose (RfD) or exposure air concentration (EC)/reference concentration (RfC); [2] LCR=lifetime average daily dose (LADD) × cancer slope factor (CSF) or exposure air concentration (EC) × inhalation unit risk (IUR). Results: Four articles pertaining to HRA of e-cigarettes were critically reviewed, three of the papers focused on specific chemicals namely nicotine, propylene glycol (PG), glycerol and 1,2-propanediol, while one article evaluated the health risks posed by heavy metals contained in e-cigarettes. The calculated HQs for the chemicals in this review had large variations. HQs of the six chemicals, i.e. nicotine, PG, glycerol, cadmium, ethylene glycol, nickel, aluminum and titanium, were found to have the potential to contribute to non-carcinogenic health risks. None of the LCR calculated had risks exceeding the acceptable limit. Conclusion: There are limited HRA studies and the ones that were available provided inconsistent scientific evidences on the health risk characterization arising from the usage of e-cigarettes. As such, there is a need to perform more studies on HRA of e-cigarettes by using uniformed and comprehensive steps and similar reference threshold levels of exposures.

The National Institute of Environmental Health Sciences (NIEHS) Superfund Research Program (SRP) funds university-based, multidisciplinary research on human health and environmental science and engineering with the central goals to understand how hazardous substances contribute to disease and how to prevent exposures to these environmental chemicals. This multi-disciplinary approach allows early career scientists (e.g. graduate students and postdoctoral researchers) to gain experience in problem-based, solution-oriented research and to conduct research in a highly collaborative environment. Training the next generation of environmental health scientists has been an important part of the SRP since its inception. In addition to basic research, the SRP has grown to include support of broader training experiences such as those in research translation and community engagement activities that provide opportunities to give new scientists many of the skills they will need to be successful in their field of research. Looking to the future, the SRP will continue to evolve its training component by tracking and analyzing outcomes from its trainees by using tools such as the NIEHS CareerTrac database system, by increasing opportunities for trainees interested in research that goes beyond US boundaries, and in the areas of bioinformatics and data integration. These opportunities will give them the skills needed to be competitive and successful no matter which employment sector they choose to enter after they have completed their training experience.

Concerns regarding indoor air quality, particularly the presence of fungi and moulds, are increasing. The potential for essential oils to reduce, control or remove fungi, is gaining interest as they are seen as a “natural” alternative to synthetic chemical fungicides. This review examines published research on essential oils as a method of fungal control in indoor environments. It was difficult to compare the relative performances of essential oils due to differences in research methods and reporting languages. In addition, there are limited studies that scale up laboratory results and assess the efficacy of essential oils within building environments. However, generally, there appears to be some evidence to support the essential oils clove oil, tea tree oil, oregano, thyme and lemon as potential antifungal agents. Essential oils from heartwood, marjoram, cinnamon, lemon basil, caraway, bay tree, fir, peppermint, pine, cedar leaf and manuka were identified in at least one study as having antifungal potential. Future studies should focus on comparing the effectiveness of these essential oils against a large number of fungal isolates from indoor environments. Studies will then need to focus on translating these results into realistic application methods, in actual buildings, and assess the potential for long-term antifungal persistence.

Mitigating the impact of pollution on human health worldwide is important to limit the morbidity and mortality arising from exposure to its effect. The level and type of pollutants vary in different urban and rural settings. Here, we explored the extent of air pollution and its impacts on human health in the megacity of Delhi (India) through a review of the published literature. The study aims at describing the extent of air pollution in Delhi, the magnitude of health problems due to air pollution and the risk relationship between air pollution and associated health effects. We found 234 published articles in the PubMed search. The search showed that the extent of air pollution in Delhi has been described by various researchers from about 1986 onwards. We synthesized the findings and discuss them at length with respect to reported values, their possible interpretations and any limitations of the methodology. The chemical composition of ambient air pollution is also discussed. Further, we discuss the magnitude of health problem with respect to chronic obstructive pulmonary diseases (COPD), bronchial asthma and other illnesses. The results of the literature search showed that data has been collected in last 28 years on ambient air quality in Delhi, though it lacks a scientific continuity, consistency of locations and variations in parameters chosen for reporting. As a result, it is difficult to construct a spatiotemporal picture of the air pollution status in Delhi over time. The number of sites from where data have been collected varied widely across studies and methods used for data collection is also non-uniform. Even the parameters studied are varied, as some studies focused on particulate matter ≤10 μm in aerodynamic diameter (PM 10 ) and those ≤2.5 μm in aerodynamic diameter (PM 2.5 ), and others on suspended particulate matter (SPM) and respirable suspended particulate matter (RSPM). Similarly, the locations of data collection have varied widely. Some of the sites were at busy traffic intersections, some on the terraces of offices and residential houses and others in university campuses or airports. As a result, the key question of the extent of pollution and its distribution across various parts of the city could be inferred. None of the studies or a combination of them could present a complete picture of the burden of diseases like COPD, bronchial asthma and other allergic conditions attributable to pollution in Delhi. Neither could it be established what fraction of the burden of the above diseases is attributable to ambient air pollution, given that other factors like tobacco smoke and indoor air pollution are also contributors to the causation of such diseases. In our discussion, we highlight the knowledge gaps and in the conclusion, we suggested what research can be undertaken to fill the these research gaps.

Human exposure to environmental contaminants such as persistent chlorinated organics, heavy metals, pesticides, phthalates, flame retardants, electronic waste and airborne pollutants around the world, and especially in Southeast Asian regions, are significant and require urgent attention. Given this widespread contamination and abundance of such toxins as persistent organic pollutants (POPs) in the ecosystem, it is unlikely that remediation alone will be sufficient to address the health impacts associated with this exposure. Furthermore, we must assume that the impact on health of some of these contaminants results in populations with extraordinary vulnerabilities to disease risks. Further exacerbating risk; infectious diseases, poverty and malnutrition are common in the Southeast Asian regions of the world. Thus, exploring preventive measures of environmental exposure and disease risk through new paradigms of environmental toxicology, optimal and/or healthful nutrition and health is essential. For example, folic acid supplementation can lower blood arsenic levels, and plant-derived bioactive nutrients can lower cardiovascular and cancer risks linked to pollutant exposure. Data also indicate that diets enriched with bioactive food components such as polyphenols and omega-3 polyunsaturated fatty acids can prevent or decrease toxicant-induced inflammation. Thus, consuming healthy diets that exhibit high levels of antioxidant and anti-inflammatory properties, is a meaningful way to reduce the vulnerability to non-communicable diseases linked to environmental toxic insults. This nutritional paradigm in environmental toxicology requires further study in order to improve our understanding of the relationship between nutrition or other lifestyle modifications and toxicant-induced diseases. Understanding mechanistic relationships between nutritional modulation of environmental toxicants and susceptibility to disease development are important for both cumulative risk assessment and the design and implementation of future public health programs and behavioral interventions.

Background: In 2010, Ontario, Canada’s most populous province, implemented its Toxics Reduction Act, Ontario Regulation 455/09 (TRA), which requires four major manufacturing and mineral processing industry groups that already report releases of pollutants federally to the National Pollutant Release Inventory to additionally track, account and report their use and creation. The TRA was modeled after the Massachusetts Toxics Use Reduction Act of 1989, which has been very successful and reported significant reduction in toxic use and carcinogen release. Methods: Data from the TRA were retrieved, and the trends in the use and release of 17 known and suspected carcinogens associated with the seven most prevalent cancers diagnosed in Ontario and reported by industrial facilities in Ontario from 2011 to 2015 were examined using methodology adapted from (Jacobs MM, Massey RI, Tenney H, Harriman E. Reducing the use of carcinogens: the Massachusetts experience. Rev Environ Health 2014;29(4):319–40). Results: Carcinogens associated with lung cancers, leukemia and lymphomas were observed as the most used and released carcinogens in Ontario by amount. Overall, for 2011–2015, there was an observed reduction in the industrial use of carcinogens, except among breast carcinogens, which increased by 20%. An increase in the industrial releases of carcinogens was observed across all cancer sites, except among lung carcinogens, which decreased by 28%. Conclusion: The results of this study highlight the potential for reducing the cancer burden by reducing the use and release of select carcinogens associated with particularly prevalent cancers. Toxics use reduction programs can support cancer prevention initiatives by promoting targeted reductions in exposures to industrial carcinogens.