Environews
NIEHS NEWS | RTP Leaders Unite to Advance Environmental Health
Over the course of decades, the NIEHS has strived to build upon its original foundation of advancing the cause of public health. Now the Research Triangle Park–based institute is joining with other leading environmental health entities, both public and private, to create a collaborative devoted to strengthening the resources of environmental health research and related sciences. This article (p. A524) discusses the creation of the Research Triangle Environmental Health Collaborative and looks ahead to some of its goals.
FOCUS | Monitoring Environmental Exposures: Now It's Personal
Until now, human exposure assessment has been stymied by a lack of understanding of precisely how the environment contributes to genetically based diseases. Thanks to new data-gathering methods being explored as part of the Genes and Environment Initiative and other research efforts, however, the field of environmental health science is poised to usher in a new era of exposure assessment research. This article (p. A528) takes a look at some of the plans for new technologies and study approaches that will allow for more precise measurement and analysis of environmental exposures at the individual level.
SPHERES OF INFLUENCE | The Price of Gold in Chile
The mining of precious metals has long raised concerns about the preservation of other equally precious resources, such as drinking water. One recent example of this potentially hazardous overlap is the Pascua-Lama mine, a proposed mining project in the Andes of Chile and Argentina. Opponents of the new mine fear that extraction activity could create a multitude of dangers for residents, but the mining company behind Pascua-Lama foresees no major threats to locals' way of life. This article (p. A536) examines some of the issues of contention swirling around the Pascua-Lama project.
INNOVATIONS | T Rays vs. Terrorists: Widening the Security Spectrum
Although there are a number of electromagnetic radiation and mass spectrometry techniques such as X rays already in use to detect terrorist weapons, these tools can come with dangerous side effects or performance limitations. Seeking to harness the benefits of electromagnetic sensors while curtailing their drawbacks, a research team at Argonne National Laboratory has tapped into new detection possibilities with terahertz and millimeter-wave technology. This article (p. A540) discusses the versatility of these new concepts that, when perfected, could help keep us a step ahead of terrorists.
Commentaries
HEALTH POLICY | Chemical Plants Remain Vulnerable to Terrorists
U.S. chemical plants currently have potentially catastrophic vulnerabilities as terrorist targets. The possible consequences of these vulnerabilities are apparent from the tragedies of the Bhopal incident to the terrorist attacks on 11 September 2001 and, most recently, Hurricanes Katrina and Rita. Lippin et al. (p. 1307) report thefindings from a 2004 nationwide participatory research study of 125 local union leaders at sites with large volumes of hazardous chemicals. The information suggests that voluntary efforts to achieve chemical plant security are not succeeding. The environmental health community thus has an opportunity to play a key role in advocating for and supporting improvements in prevention and preparation for terrorist attacks.
RISK ASSESSMENT | The Chernobyl Accident 20 Years Later
The Chernobyl accident in 1986 caused widespread radioactive contamination and enormous concern. Twenty years later, the World Health Organization and the International Atomic Energy Authority issued a generally reassuring statement about the consequences. Baverstock and Williams (p. 1312) evaluate the health impact of the Chernobyl accident, assess the international response, and consider how to improve responses to future accidents. So far, radiation to the thyroid has caused several thousand cases of cancer but very few deaths. Accurate assessment of future health effects is not currently possible because of to dose uncertainties, current debates over radiation actions, and the lessons from the long-term consequences of atomic bomb exposure.
Review
CLIMATE CHANGE | Health Impacts of Climate Change in the United States
The health sector component of the first U.S. National Assessment synthesized the anticipated health impacts of temperature, extreme weather events, air pollution, water- and food borne diseases, and vector borne diseases. The Health Sector Assessment (HSA) concluded that climate variability and change are likely to increase morbidity and mortality risks for several climate-sensitive health outcomes, with the net impact uncertain. Ebi et al. (p. 1318) discuss updates to the first HSA based on recent publications that address the potential impacts of climate variability and change in the United States.
Research
RESPIRATORY DISEASE | Nanoparticles and Lung Inflammation
Although adverse health effects of particulate matter with a diameter of < 100 nm (nanoparticles) have been proposed, molecular and/or experimental evidence for their facilitation of lung inflammation in vivo is not fully defined. Inoue et al. (p. 1325) investigated the effects of nanoparticles on lung inflammation related to bacterial endotoxin (lipopolysaccharide) in mice. The evidence indicates that nanoparticles can aggravate lung inflammation related to bacterial endotoxin, which is more prominent with smaller particles. The enhancement may be mediated, at least partly, via the increased local expression of proinflammatory cytokines and via oxidative stress. Nanoparticles can also promote coagulatory disturbance accompanied by lung inflammation.
Also see Science Selections, p. A545
CARDIOVASCULAR DISEASE | Subpopulations Vulnerable to Temperature Extremes
Extremes of temperature are associated with short-term increases in daily mortality. Medina-Ramón et al. (p. 1331) identified several subpopulations and causes of mortality particularly susceptible to temperature extremes. A case-only analysis was conducted using daily mortality and hourly weather data from 50 U.S. cities. Older subjects, diabetics, blacks, and those dying outside a hospital were more susceptible to extreme heat, with some differences observed between those dying from a cardiovascular disease and other decedents. Cardiovascular deaths, and especially cardiac arrest deaths, showed a greater relative increase on extremely cold days, whereas the increase in heat-related mortality was marginally higher for those with coexisting atrial fibrillation.
Also see Science Selections, p. A545
GENE EXPRESSION | Gene Expression Changes with Methylmercury Exposure
Methylmercury (MeHg) is a known neurotoxic agent, but the mechanisms by which MeHg may act on reproductive pathways are relatively unknown. Several studies have indicated potential changes in hormone levels, as well as declines in vertebrates, with increasing dietary MeHg exposure. Klaper et al. (p. 1337) identified alterations in gene expression associated with MeHg exposure, specifically those associated with previously observed changes in reproduction and reproductive biomarkers. Gene expression data may provide insight into the mechanisms by which MeHg affects reproduction in fish and may indicate how the effects of MeHg differ from those of other heavy metals and endocrine-disrupting compounds.
CLIMATE CHANGE | Ozone, Temperature, and Mortality during Heat Wave
During August 2003, record high temperatures were observed across Europe, with France being the most affected; during this period, elevated ozone concentrations were measured all over the country. Filleul et al. (p. 1344) address questions raised about the contribution of O3 to health impact during the 2003 summer heat wave. For nine cities, the excess risk of death was significant for a 10-µg/m3 increase in O3. Heterogeneity was observed among the nine cities not only for the joint effect of O3 and temperatures but also for the relative contribution of each factor.
REPRODUCTIVE HEALTH | POPs and Reproductive Hormones
Persistent organohalogen pollutant (POP) exposure may have a negative impact on reproductive function. Giwercman et al. (p. 1348) assessed the impact of POP exposure on the male hypothalamo–pituitary–gonadal axis. Serum levels of 2,2´,4,4´,5,5´-hexachlorobiphenyl and dichlorodiphenyldichloroethene were determined in four populations, showing different exposure patterns. Serum was also analyzed for testosterone, estradiol, sex hormone-binding globulin (SHBG), inhibin B, luteinizing hormone, and follicle-stimulating hormone. Free testosterone levels were calculated based on testosterone and SHBG.Gonadotropin levels and SHBG seem to be affected by POP exposure, but the pattern of endocrine response is subject of considerable geographic variation.
RESPIRATORY DISEASE | Ozone-Tolerant Airways Are More Susceptible to 1-NN
Ambient air is polluted with a mixture of pulmonary toxicants. Previous studies indicate that prior exposure to atmospheric oxidant pollutants, such as ozone, may significantly alter the response to other pollutants, such as 1-nitronaphthalene (1-NN), a component of diesel exhaust. Using a metabolomic approach, Schmelzer et al. (p. 1354) investigated inflammatory responses in arachidonic and linoleic acid biochemical cascades (35 metabolites) and the expression of 19 cytokines and chemokines. The study indicates that airways of O3-tolerant rats exhibited a low level of chronic inflammation, rendering the lungs more susceptible to other environmental pollutants such as 1-NN.
RISK ASSESSMENT | Indoor Radon Risk Assessment in France
The inhalation of radon, a well-established human carcinogen, is the principal omnipresent source of radioactivity for the general population of most countries. Scientists have sought to assess the lung cancer risk associated with indoor radon. Catelinois et al. (p. 1361) assess this risk in France, using all available epidemiologic results and performing uncertainty analyses. Different exposure–response relations from several epidemiologic studies were used. The authors found that the number of lung cancer deaths attributable to indoor radon appears relatively stable. Smokers can reduce their risk not only by reducing their indoor radon concentration but also by giving up smoking.
RESPIRATORY DISEASE | Coal Dust Increases Pulmonary Apoptosis
Miners inhaling respirable coal dust (CD) frequently develop dust-associated coal workers' pneumoconiosis, characterized by lung inflammation and variable fibrosis. Many coal miners are also exposed to polycyclic aromatic hydrocarbons (PAHs) and cigarette smoke. CD was recently reported to suppress cytochrome P450 1A1 (CYP1A1) induction by PAHs. Ghanem et al. (p. 1367) investigated the hypothesis that apoptosis plays a critical role in lung injury and down-regulation of CYP1A1 induction in mixed exposures to CD and PAHs. Combined β-naphthoflavone and CD exposure increased Bax expression and apoptosis in the lung, but Bax and apoptosis were not the major determinants of early lung injury in this model.
EXPOSURE ASSESSMENT | Geographic Information Systems to Estimate Residential-Level Ambient PM
Spatial estimations are increasingly used to estimate geocoded ambient particulate matter (PM) concentrations in epidemiologic studies because measures of daily PM concentrations are unavailable in most U.S. locations. Liao et al. (p. 1374) conducted a study to assess the feasibility of large-scale kriging estimations of daily residential-level ambient PM concentrations, perform and compare cross-validations of different kriging models, contrast three popular kriging approaches, and calculate standard errors of the kriging estimations. Semiautomated daily kriging estimations and semivariogram cross-validations are feasible on a national scale. Log-normal ordinary kriging with a spherical model is valid for estimating daily ambient PM at geocoded residential addresses.
EXPOSURE ASSESSMENT | Bioaerosols in New Orleans after Flooding
The hurricanes and flooding in New Orleans, Louisiana, in October and November 2005 resulted in damp conditions favorable to the dispersion of bioaerosols such as mold spores and endotoxin. Solomon et al. (p. 1381) assessed the potential human exposure to bioaerosols after the flooding of the city. The high concentration of mold measured indoors and outdoors in the New Orleans area is likely to be a significant respiratory hazard that should be monitored over time. Workers and returning residents should use appropriate personal protective equipment and exposure mitigation techniques to prevent respiratory morbidity and long-term health effects.
EXPOSURE ASSESSMENT | Sources, Composition, and Toxicity of Ambient PM2.5
Exposure to air pollution and, more specifically, particulate matter (PM) is associated with adverse health effects. However, the specific PM characteristics responsible for biological effects have not been defined. Seagrave et al. (p. 1387) examined the composition, sources, and relative toxicity of samples collected from sites within the Southeastern Aerosol Research and Characterization (SEARCH) air monitoring network. These sites represent four areas with differing sources of PM2.5, including local urban versus regional sources, urban areas with different contributions of transportation and industrial sources, and a site influenced by Gulf of Mexico weather patterns. Urban sites with high contributions from vehicles and industry were most toxic.
TOXICOLOGY | Fat and CYP1A2 Induction on TCDD Pharmacokinetics
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly lipophilic chemical that distributes into adipose tissue, especially at low doses. However, at high doses, TCDD sequesters in liver because it induces cytochrome P450 1A2 (CYP1A2) that binds TCDD. A physiologically based pharmacokinetic (PBPK) model was developed that included an inducible elimination rate of TCDD. The objective was to characterize the influence of induction of CYP1A2 and adipose tissue mass fraction on the terminal elimination half-life of TCDD using this PBPK model. Emond et al. (p. 1394) demonstrate that an inducible elimination rate is needed in a PBPK model in order to describe the pharmacokinetics of TCDD.
CELL CYCLE CONTROL | p53 Alters Exit from Mitotic Arrest by Arsenite
Arsenic is both a human carcinogen and a chemotherapeutic agent, but the mechanisms of arsenic-induced carcinogenesis and tumor selective cytotoxicity are unclear. Using a model cell line in which p53 expression is regulated exogenously in a tetracycline-off system (TR9-7 cells), McNeely et al. (p. 1401) show that arsenite disrupts mitosis and that p53-deficient cells display greater sensitivity to arsenite-nduced mitotic arrest and apoptosis than p53-expressing cells. p53 promotes mitotic exit and leads to more extensive induction of DNA binding 1 (ID1) by arsenite. ID1 is a dominant negative inhibitor of transcription that represses cell cycle regulatory genes and is elevated in many tumors.
POPULATION HEALTH | Environmental Health Indicators in the Americas
Carneiro et al. (p. 1407) summarize the Brazilian experience with environmental health indicators, with contributions from Cuba, Argentina, and Canada, presented at the International Symposium on the Development of Indicators for Environmental Health Integrated Management, held in Recife, Pernambuco, Brazil, in June 2004. The methodology for the development of environmental health indicators has been used as a reference in the implementation of environmental health surveillance in Brazil. This methodology has provided tools and processes to better understand and to measure determinants of environmental health risks for decision makers.
Environmental Medicine
RESPIRATORY DISEASE | PVC Material Challenge
Polyvinyl chloride (PVC) materials have been linked to asthma in several epidemiologic studies, but the possible causal factors remain unknown. Tuomainen et al. (p. 1409) challenged 10 subjects experimentally to degraded PVC products under controlled conditions. All subjects had previously experienced respiratory symptoms suspected to be caused by this kind of exposure in their work place, and 5 subjects had doctor-diagnosed asthma. The authors found that the PVC flooring challenge can evoke respiratory tract symptoms in exposed subjects. The results do not support the proposal that PVC materials themselves evoke immediate asthmatic reactions.
Children's Health
INFECTIOUS DISEASE | Air Pollution and Otitis Media
Otitis media is one of the most common infections in young children. Although exposure to environmental tobacco smoke is a known risk factor associated with otitis media, little information is available regarding the potential association with air pollution. Brauer et al. (p. 1414) studied the relationship between exposure to traffic-related air pollution and otitis media in two birth cohorts. Their findings indicate an association between exposure to traffic-related air pollutants and the incidence of otitis media. Given the ubiquitous nature of air pollution exposure and the importance of otitis media to children's health, these findings have significant public health implications.
Also see Science Selections, p. A544
EXPOSURE ASSESSMENT | Children's Exposures to Pyrethroid Pesticides
Lu et al. (p. 1419) conducted a longitudinal study to assess the exposure of elementary school–age children to pyrethroid pesticides, using urinary pyrethroid metabolites as exposure biomarkers. The children's conventional diets were substituted with organic food items for 5 consecutive days, and two daily spot urine samples were collected throughout the 15-day study period. The authors found an association between the parents' self-reported pyrethroid use in the residential environment and elevated pyrethroid metabolite levels found in their children's urine. Children were also exposed to pyrethroids through their conventional diets, although the magnitude was smaller than for the residential exposure.
Also see Science Selections, p. A544
EXPOSURE ASSESSMENT | Exposure to Phthalates in NICU Infants
Weuve et al. (p. 1424) previously demonstrated that among infants in neonatal intensive care units, exposure to polyvinyl chloride plastic medical devices containing the plasticizer di(2-ethylhexyl) phthalate (DEHP) is associated with urinary concentrations of mono(2-ethylhexyl) phthalate, a DEHP metabolite. In this report, neonate exposure to DEHP-containing devices was studied in relation to urinary concentrations of two other DEHP metabolites, and to urinary concentrations of metabolites of dibutyl phthalate and benzylbutyl phthalate, both found in construction materials and personal care products. Intensiveness of DEHP-containing product use was monotonically associated with all three DEHP metabolites.
RESPIRATORY DISEASE | Air Pollution and Children's Lung X Rays
Calderón-Garcidueñas et al. (p. 1432) analyzed the chest radiographs of clinically healthy children from southwest Mexico City and Tlaxcala, Mexico. In contrast to children from Tlaxcala, children from Mexico City were chronically exposed to ozone levels exceeding the U.S. National Ambient Air Quality Standards and to concentrations of particulate matter (PM) with aerodynamic diameters ≤2.5 µm above the annual standard. Results from the radiographs are consistent with bronchiolar, peribronchiolar, and/or alveolar duct inflammation, possibly caused by O3, PM, and lipopolysaccharide exposure. The epidemiologic implications are important for children residing in polluted environments, because bronchiolar disease could lead to chronic pulmonary disease later in life.
NEUROBEHAVIORAL DISEASE | Autism and Hazardous Air Pollutants
To explore possible associations between autism spectrum disorders and environmental exposures, Windham et al. (p. 1438) linked the California autism surveillance system to estimated hazardous air pollutant concentrations compiled by the U.S. Environmental Protection Agency. Adjusting for various groups simultaneously led to decreased risks for solvents and increased risk for metals. The individual compounds that contributed most included mercury, cadmium, nickel, trichloroethylene, and vinyl chloride. The results suggest a potential association between autism and estimated metal concentrations—and possibly solvents—in ambient air around the birth residence. The results require confirmation and more refined exposure assessment in future studies.
Mini-Monograph
RISK ASSESSMENT | Issues in TCE Risk Assessment
Trichloroethylene (TCE) is a common environmental contaminant at hazardous waste sites and in ambient and indoor air. Because of TCE's inheriently complex metabolism and toxicity, the U.S. Environmental Protection Agency drew upon scientific input and expertise from a wide range of groups and individuals in developing its 2001 draft health risk assessment of TCE. The articles included in this mini-monograph (p. 1445) provide a scientific update on the most prominent current issues: the pharmacokinetics of TCE and its metabolites, mode(s) of action and effects of TCE metabolites, the role of peroxisome proliferator–activated receptor in TCE toxicity, and TCE cancer epidemiology.
