Arsenic Exposure-Related Hypertension in Bangladesh and Reduced Circulating Nitric Oxide Bioavailability.

BACKGROUND: Hypertension is a major cause of death worldwide. Although arsenic exposure has been associated with the risk of hypertension, this association appears nonuniform due to inconsistent results from studies conducted in different populations. Moreover, hypertension is a complex condition with multiple underlying mechanisms and factors. One factor is impaired production and bioavailability of vascular nitric oxide (NO). However, the implications of the effects of arsenic exposure on circulating NO and its association with hypertension in humans are largely unknown. OBJECTIVE: We investigated the dose-response relationship between arsenic exposure and hypertension with vascular NO levels as a potential mediator of arsenic-related hypertension in individuals exposed to a broad range of arsenic. METHODS: A total of 828 participants were recruited from low- and high-arsenic exposure areas in Bangladesh. Participants' drinking water, hair, and nail arsenic concentrations were measured by inductively coupled plasma mass spectroscopy. Hypertension was defined as a systolic blood pressure (SBP) value of ≥140 and a diastolic (DBP) value of ≥90 mmHg. Serum NO levels reflected by total serum nitrite concentrations were measured by immunoassay. A formal causal mediation analysis was used to assess NO as a mediator of the association between arsenic level and hypertension. RESULTS: Increasing concentrations of arsenic measured in drinking water, hair, and nails were associated with the increasing levels of SBP and DBP. The odds of hypertension were dose-dependently increased by arsenic even in participants exposed to relatively low to moderate levels (10-50µg/L) of water arsenic [odds ratios (ORs) and 95% confidence intervals (CIs): 2.87 (95% CI: 1.28, 6.44), 2.67 (95% CI: 1.27, 5.60), and 5.04 (95% CI: 2.71, 9.35) for the 10-50µg/L, 50.01-150µg/L, and >150µg/L groups, respectively]. Causal mediation analysis showed a significant mediating effect of NO on arsenic-related SBP, DBP, and hypertension. CONCLUSION: Increasing exposure to arsenic was associated with increasing odds of hypertension. The association was mediated through the reduction of vascular NO bioavailability, suggesting that impaired NO bioavailability was a plausible underlying mechanism of arsenic-induced hypertension in this Bangladeshi population. https://doi.org/10.1289/EHP13018.

Clerodendrum viscosum leaves attenuate lead-induced neurotoxicity through upregulation of BDNF-Akt-Nrf2 pathway in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Clerodendrum viscosum is an important medicinal plant in Ayurveda in Bangladesh and its leaves are used as a remedy for various diseases such as anti-inflammatory, antibacterial, hyperglycemic, hepatoprotective effects. AIM OF THE STUDY: The present study aimed to evaluate the protective effect of aqueous extract of C. viscosum leaves against Pb-induced neurobehavioral and biochemical changes in mice. MATERIALS AND METHODS: Swiss albino mice were divided as a) control, b) lead treated (Pb) and c) C. viscosum leaves (Cle) d) Pb plus Cle groups. Pb-acetate (10 mg/kg body weight) was given to Pb and Pb + Cle groups mice, and water extract of leaves (50 mg/kg body weight) was provided as supplementation to Cle and Pb + Cle groups mice for 30 days. Elevated plus maze and Morris water maze tests were used for evaluating anxiety, spatial memory and learning, respectively. Status of cholinesterase, SOD, GSH enzyme activity and neurotoxicity markers such BDNF and Nrf2 levels were analyzed in the brain tissue of experimental mice. RESULTS: Poorer learning, inferior spatial memory, and increased anxiety-like behavior in Pb-exposure mice were noted when compared to control mice in Morris water maze and elevated plus maze test, respectively. In addition, expression of BDNF and Nrf2, cholinesterase activity along with antioxidant activity were significantly reduced compared to control group (p < 0.01). Interestingly, C. viscosum leaves' aqueous extract supplementation in Pb-exposed mice provide a significant improved neurochemical and antioxidant properties through the augmentation of activity of cholinergic enzymes, and upregulation of BDNF and Nrf2 levels in the brain tissue compared to Pb-exposed mice. CONCLUSIONS: This study suggested that C. viscosum leaves restore the cognitive dysfunction and reduce anxiety-like behavior through upregulation of BDNF mediated Akt-Nrf2 pathway in Pb-exposure mice.

Recent Advances in Monitoring, Sampling, and Sensing Techniques for Bioaerosols in the Atmosphere.

Bioaerosols in the form of microscopic airborne particles pose pervasive risks to humans and livestock. As either fully active components (e.g., viruses, bacteria, and fungi) or as whole or part of inactive fragments, they are among the least investigated pollutants in nature. Their identification and quantification are essential to addressing related dangers and to establishing proper exposure thresholds. However, difficulties in the development (and selection) of detection techniques and an associated lack of standardized procedures make the sensing of bioaerosols challenging. Through a comprehensive literature search, this review examines the mechanisms of conventional and advanced bioaerosol detection methods. It also provides a roadmap for future research and development in the selection of suitable methodologies for bioaerosol detection. The development of sample collection and sensing technology make it possible for continuous and automated operation. However, intensive efforts should be put to overcome the limitations of current technology as most of the currently available options tend to suffer from lengthy sample acquisition times and/or nonspecificity of probe material.

Environmental impacts of nanomaterials.

Nanotechnology is currently one of the highest priority research fields in many countries due to its immense potentiality and economic impact. Nanotechnology involves the research, development, production, and processing of structures and materials on a nanometer scale in various fields of science, technology, health care, industries, and agriculture. As such, it has contributed to the gradual restructuring of many associated technologies. However, due to the uncertainties and irregularities in shape, size, and chemical compositions, the presence of certain nanomaterials may exert adverse impacts on the environment as well as human health. Concerns have thus been raised about the destiny, transport, and transformation of nanoparticles released into the environment. A critical evaluation of the current states of knowledge regarding the exposure and effects of nanomaterials on the environment and human health is discussed in this review. Recognition on the potential advantages and unintended dangers of nanomaterials to the environment and human health is critically important to pursue their development in the future.

Airborne bioaerosols and their impact on human health.

Bioaerosols consist of aerosols originated biologically such as metabolites, toxins, or fragments of microorganisms that are present ubiquitously in the environment. International interests in bioaerosols have increased rapidly to broaden the pool of knowledge on their identification, quantification, distribution, and health impacts (e.g., infectious and respiratory diseases, allergies, and cancer). However, risk assessment of bioaerosols based on conventional culture methods has been hampered further by several factors such as: (1) the complexity of microorganisms or derivatives to be investigated; (2) the purpose, techniques, and locations of sampling; and (3) the lack of valid quantitative criteria (e.g., exposure standards and dose/effect relationships). Although exposure to some microbes is considered to be beneficial for health, more research is needed to properly assess their potential health hazards including inter-individual susceptibility, interactions with non-biological agents, and many proven/unproven health effects (e.g., atopy and atopic diseases).

Exposure to pesticides and the associated human health effects.

Pesticides are used widely to control weeds and insect infestation in agricultural fields and various pests and disease carriers (e.g., mosquitoes, ticks, rats, and mice) in houses, offices, malls, and streets. As the modes of action for pesticides are not species-specific, concerns have been raised about environmental risks associated with their exposure through various routes (e.g., residues in food and drinking water). Although such hazards range from short-term (e.g., skin and eye irritation, headaches, dizziness, and nausea) to chronic impacts (e.g., cancer, asthma, and diabetes), their risks are difficult to elucidate due to the involvement of various factors (e.g., period and level of exposure, type of pesticide (regarding toxicity and persistence), and the environmental characteristics of the affected areas). There are no groups in the human population that are completely unexposed to pesticides while most diseases are multi-causal to add considerable complexity to public health assessments. Hence, development of eco-friendly pesticide alternatives (e.g., EcoSMART) and Integrated Pest Management (IPM) techniques is desirable to reduce the impacts of pesticides. This paper was hence organized to present a comprehensive review on pesticides with respect to their types, environmental distribution, routes of exposure, and health impacts.

Review of electronic cigarettes as tobacco cigarette substitutes: Their potential human health impact.

Electronic cigarettes (ECs) are devised to deliver nicotine in a vapor rather than in smoke without tar. ECs are hence advertised as being safer than tobacco cigarette products as the chemical compounds inhaled in the former are believed to be fewer and less toxic than those of the latter. Hazardous chemicals (e.g., formaldehyde) are nonetheless found to be generated incidentally by contacting the heated wire (i.e., the oxidation of glycerol/glycol in e-liquid). Although the extent of their release varies by several variables (e.g., the type of e-liquid, puffing rate, and the battery voltage), their exposure may also contribute to negative health effects. As the use of ECs may be much safer than that of common tobacco products, the former can be used as an aid to cut down or quit the latter. However, relatively little is yet known about the health effects of the EC on a long-term basis. Moreover, the use of EC cannot be clearly substantiated for renormalizing smoking behavior by current evidence. Behavior studies of the EC consumer suggest that the sufficient data for aerosol generation and chemical analysis should be acquired to establish reliable guides for its composition and consumption. In light of the urgent demand for such guidelines, this review examines the basic aspects of EC-related pollutants and their health effects.

Waterpipe tobacco smoking and its human health impacts.

Waterpipe tobacco smoking (WTS, also known as hookah, shisha, narghile, and many other names) involves passing tobacco smoke through water prior to inhalation by the consumer. As the number of waterpipe smokers is rising rapidly, there is growing concern over the use of WTS, particularly as there has been a widely held misconception that WTS is free from health hazards. In reality, it is associated with a variety of adverse health outcomes on both a short- and long-term basis. Hence, it is desirable to develop advanced techniques for surveillance, intervention, and regulatory/policy frameworks specific to the production and use of waterpipe tobacco. This review is written to survey the types and extent of pollutants released from its use and their potential health risks. A review of the present regulation guidelines is also included.

The use of cell phone and insight into its potential human health impacts.

The rapid evolution of mobile phone technology has raised public concern about its possible association with adverse health effects. Given the huge number of mobile phone users at present days, even simple adverse health effects could have major implications. This article reviews the present knowledge concerning the health effects stemming from the use of cellular phones by emphasizing adverse biological effects, epidemiological issues, and indirect health effects. A line of epidemiological evidence suggests that there is no concrete association between mobile phone radiation and cancer. The evidence regarding the occurrence of cancer due to exposure to the radio frequency energy of mobile phones is nonetheless conflicting. Consequently, long-term research in this field is necessary to account for the vital issue of this scientific research to the public in a meaningful way.

The use of personal hair dye and its implications for human health.

Hair dye products now represent one of the most rapidly growing beauty and personal care industries as both men and women commonly change hair color to enhance youth and beauty and to follow fashion trends. Irrespective of economic and education status, people dye their hair to emphasize the importance given to appearance. Despite adverse reactions, many people continue dyeing mainly for cosmetic purposes. This paper provides a comprehensive review on various aspects of hair dying products, especially with respect to the hair-coloring process, classification, chemical ingredients, possible human health impacts, and regulations. Permanent hair dye, which is the most commonly used product type, is formed by an oxidative process involving arylamines to bring about concerns with long-term exposure. Hence, significant efforts have been put to understand the possible side effects of such exposure including cancer risk. However, hair dyes and their ingredients are mainly identified to have moderate to low acute toxicity such as the cause of allergic contact dermatitis. Although some hair dye components are reported to be carcinogenic in animals, such evidence is not consistent enough in the case of human studies. Consequently, further research is desirable to critically address the significance of this issue, especially with respect to the safety of hair dye ingredients.

A review on the distribution of Hg in the environment and its human health impacts.

Exposure to mercury is a silent threat to the environment and human life. It has the potential to harm almost every organ and body system. Mercury compounds are classified in different chemical types such as elemental, inorganic, and organic forms. The most significant source of ingestion-related mercury exposure in humans and animals is the consumption of fish. Long-term exposure to mercury compounds from different sources (e.g., water, food, soil, and air) can lead to toxic effects on skin, cardiovascular, pulmonary, urinary, gastrointestinal, and neurological systems. Mercury toxicity is found to pose more significant health hazards to certain occupational groups (e.g., goldminers and dental personnel). Because continuous exposure to mercury can be dangerous, it is desirable to re-evaluate the current reference (risk-free) values. This paper reviews the route of Hg exposure to humans, its human health impacts, the associated risk assessment, and treatment based on the recent findings from various studies.

A review on the human health impact of airborne particulate matter.

Particulate matter (PM) is a key indicator of air pollution brought into the air by a variety of natural and human activities. As it can be suspended over long time and travel over long distances in the atmosphere, it can cause a wide range of diseases that lead to a significant reduction of human life. The size of particles has been directly linked to their potential for causing health problems. Small particles of concern include "inhalable coarse particles" with a diameter of 2.5 to 10µm and "fine particles" smaller than 2.5µm in diameter. As the source-effect relationship of PM remains unclear, it is not easy to define such effects from individual sources such as long-range transport of pollution. Because of the potent role of PM and its associated pollutants, detailed knowledge of their human health impacts is of primary importance. This paper summarizes the basic evidence on the health effects of particulate matter. An in-depth analysis is provided to address the implications for policy-makers so that more stringent strategies can be implemented to reduce air pollution and its health effects.

A review of the consequences of global climate change on human health.

The impact of climate change has been significant enough to endanger human health both directly and indirectly via heat stress, degraded air quality, rising sea levels, food and water security, extreme weather events (e.g., floods, droughts, earthquakes, volcano eruptions, tsunamis, hurricanes, etc.), vulnerable shelter, and population migration. The deterioration of environmental conditions may facilitate the transmission of diarrhea, vector-borne and infectious diseases, cardiovascular and respiratory illnesses, malnutrition, etc. Indirect effects of climate change such as mental health problems due to stress, loss of homes, economic instability, and forced migration are also unignorably important. Children, the elderly, and communities living in poverty are among the most vulnerable of the harmful effects due to climate change. In this article, we have reviewed the scientific evidence for the human health impact of climate change and analyzed the various diseases in association with changes in the atmospheric environment and climate conditions.

A review of airborne polycyclic aromatic hydrocarbons (PAHs) and their human health effects.

Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds comprised of two or more fused benzene rings arranged in various configurations. PAHs are widespread environmental contaminants formed as a result of incomplete combustion of organic materials such as fossil fuels. The occurrence of PAHs in ambient air is an increasing concern because of their carcinogenicity and mutagenicity. Although emissions and allowable concentrations of PAHs in air are now regulated, the health risk posed by PAH exposure suggests a continuing need for their control through air quality management. In light of the environmental significance of PAH exposure, this review offers an overview of PAH properties, fates, transformations, human exposure, and health effects (acute and chronic) associated with their emission to the atmosphere. Biomarkers of PAH exposure and their significance are also discussed.

A review on human health perspective of air pollution with respect to allergies and asthma.

The increase in cases of asthma and allergies has become an important health issue throughout the globe. Although these ailments were not common diseases a few short decades ago, they are now affecting a large part of the population in many regions. Exposure to environmental (both outdoor and indoor) pollutants may partially account for the prevalence of such diseases. In this review, we provide a multidisciplinary review based on the most up-to-date survey of literature regarding various types of airborne pollutants and their associations with asthma-allergies. The major pollutants in this respect include both chemical (nitrogen dioxide, ozone, sulfur dioxide, particulate matter, and volatile organic compounds) and biophysical parameters (dust mites, pet allergens, and mold). The analysis was extended further to describe the development of these afflictions in the human body and the subsequent impact on health. This publication is organized to offer an overview on the current state of research regarding the significance of air pollution and its linkage with allergy and asthma.

Current status of trace metal pollution in soils affected by industrial activities.

There is a growing public concern over the potential accumulation of heavy metals in soil, owing to rapid industrial development. In an effort to describe the status of the pollutions of soil by industrial activities, relevant data sets reported by many studies were surveyed and reviewed. The results of our analysis indicate that soils were polluted most significantly by metals such as lead, zinc, copper, and cadmium. If the dominant species are evaluated by the highest mean concentration observed for different industry types, the results were grouped into Pb, Zn, Ni, Cu, Fe, and As in smelting and metal production industries, Mn and Cd in the textile industry, and Cr in the leather industry. In most cases, metal levels in the studied areas were found to exceed the common regulation guideline levels enforced by many countries. The geoaccumulation index (I(geo)), calculated to estimate the enrichment of metal concentrations in soil, showed that the level of metal pollution in most surveyed areas is significant, especially for Pb and Cd. It is thus important to keep systematic and continuous monitoring of heavy metals and their derivatives to manage and suppress such pollution.

Indoor air quality assessment in child care and medical facilities in Korea.

In order to characterize the status of indoor air pollution in some important facilities, a list of key criteria pollutants [particulate matter (PM(10)), carbon dioxide (CO(2)), carbon monoxide (CO), formaldehyde (HCHO), and bioaerosol] was measured from a total of 91 randomly selected sites in 18 different cities, Korea (February 2006 to December 2009). The target facilities include 43 child care facilities, 38 medical facilities, 6 elementary schools, and 4 postnatal care centers. The results showed that some air pollutants (e.g., CO and HCHO) did not exceed the recommended guideline [e.g., the Korean indoor air standard (KIAS) values of 10 ppm and 100 ppb, respectively]. However, concentration of PM(10), CO(2), and bioaerosol occasionally exceeded their respective guidelines (e.g., seven, three, and two cases). Discrete seasonalities were observed from indoor pollutants because of varying ventilation practice (e.g., summer time dominance of PM(10), HCHO, and bioaerosol or winter dominance of CO(2) and CO). However, as the concentrations of the indoor pollutants were scarcely above the recommended guideline level, more diversified approaches are desirable to diagnose the status of indoor pollution and to provide a realistic strategy for the improvement of IAQ.

The modern paradox of unregulated cooking activities and indoor air quality.

Pollutant emission from domestic and commercial cooking activities is a previously neglected area of concern with respect to human health worldwide. Its health effects are relevant to people across the globe, not only those using low quality food materials in lesser-developed countries but also to more affluent people enjoying higher quality food in developed countries. Based on the available database of pollutant emissions derived from fire-based cooking, its environmental significance is explored in a number of ways, especially with respect to the exposure to hazardous vapors and particulate pollutants. Discussion is extended to describe the risk in relation to cooking methods, cooking materials, fuels, etc. The observed pollutant levels are also evaluated against the current regulations and guidelines established in national and international legislation. The limitations and future prospects for the control of cooking hazards are discussed.

A review of diseases associated with household air pollution due to the use of biomass fuels.

Nearly one third of the world's population use biomass fuels such as coal, wood, animal dung, and crop residues as their primary source of domestic energy. Due to their incomplete combustion, a multitude of pollutants associated with high levels of indoor air pollution (IAP) are released which include suspended particulate matter (SPM), carbon monoxide, formaldehyde, nitrogen dioxide, polycyclic aromatic hydrocarbons (PAH), etc. There is a line of evidence that exposure to those pollutants can lead to increased risk of diseases including respiratory infections (e.g., pneumonia, tuberculosis and chronic obstructive pulmonary disease (COPD), lung cancer, and asthma), low birth weight, cataracts, and cardiovascular events. It is one of the major global public health threats that require greater efforts for prevention through research and policy-making. This review summarizes the available information on potential health risks associated with biomass fuel use.