Environews
FOCUS | Bringing Green Homes within Reach: Healthier Housing for More People
Green homes link sustainable materials and practices with better human and environmental health, and a growing number of homebuilders are embracing green design and construction techniques. There is still a perception, though, that green homes are too expensive for most people. This article (p. A24) discusses the financial realities of green homebuilding and efforts by the housing industry to make sustainable housing affordable for more people.
SPHERES OF INFLUENCE | Room to Grow: Incentives Boost Energy-Efficient Homebuilding
Now that the building industry has begun in earnest to incorporate more sustainable methods and materials into the construction of new homes, the question of how to finance these structures has become a priority on both the national and local levels. This article (p. A32) looks at how federal and local governments, utilities, and independent organizations are implementing new incentives to encourage the adoption of green building standards on a wider basis.
Research
CARCINOGENESIS | Arsenite-Induced Human Keratinocyte Transformation through the PI-3K/Akt Pathway
In Vietnam, shigellosis/dysentery, typhoid fever, and cholera are important enteric diseases. To better understand the epidemiology of these diseases, Kelly-Hope et al. (p. 7) determined temporal trends, seasonal patterns, and climatic factors associated with high-risk periods in eight regions across Vietnam. From national surveillance data for 1991-2001, monthly cases and incidence rates were quantified for each region. Precipitation, temperature, and humidity were compared between high- and low-risk periods using general linear models. Results indicate that bacterial enteric diseases have distinct temporal trends and seasonal patterns. Although climate plays a role in defining high- and low-disease periods, it does not appear to have an important influence on outbreaks.
TOXICOGENOMICS | Pulmonary Exposure to Zinc and Cardiac Effects<
Exposure to particulate matter (PM) has been associated with increased cardiovascular morbidity, but the specific causative components are unknown. Ambient PM contains significant quantities of zinc, which varies by location. Kodavanti et al. (p. 13) investigated the role of PM-associated zinc in cardiac injury in Wistar Kyoto rats. Total cardiac aconitase activity was inhibited in animals that received soluble zinc. Expression array analysis of heart tissue revealed modest changes in mRNA for genes involved in signaling, ion channel function, oxidative stress, mitochondrial fatty acid metabolism, and cell-cycle regulation in zinc-exposed rats but not rats exposed to Mount St. Helens ash. The results suggest that water-soluble PM-associated zinc may be involved in PM cardiac effects.
BIOMONITORS | Urinary Deoxynivalenol and Cereal Intake
Deoxynivalenol (DON) is a toxic fungal metabolite that frequently contaminates cereal crops. It is toxic to animals, but the effects on humans are poorly understood, in part because exposure estimates are of limited precision. The majority of adults in the United Kingdom appear to be exposed to DON; on the basis of urinary levels of DON, Turner et al. (p. 21) estimated that some individuals may exceed the European Union recommended maximum tolerable daily intake of 1,000 ng DON/kg body weight. This biomarker will be a valuable tool in surveillance strategies and in etiologic studies of DON and human disease risk.
BIOMONITORS | Methylmercury Antidote and Biomonitoring Agent
Through consumption of seafood or other anthropogenic sources, many people are exposed to levels of methylmercury (MeHg) that are generally considered to be quite low; however, these levels may nevertheless produce irreversible brain damage, particularly in unborn babies. The only way to prevent or ameliorate MeHg toxicity is to enhance its elimination from the body. Using N-acetylcysteine (NAC), Aremu et al. (p. 26) devised a monitoring protocol for early detection of acute exposure or relatively low MeHg levels in a rodent model, and investigated whether NAC reduces MeHg levels in the developing embryo.
Also see Science Selections, p. A36
RISK ASSESSMENT | Direct Evidence of Bisphenol A Binding to Human ERR-γ
When present in very low doses, bisphenol A acts as an endocrine disruptor. BPA was previously shown to bind strongly to human estrogen-related receptor-γ (ERR-γ) in a binding assay using [3H]4-hydroxytamoxifen. Okada et al. (p. 32) investigated whether BPA interacts with ERR-γ as a strong binder and they also examined the structural requirements of BPA for its binding to ERR-γ. Results indicate that the phenol derivatives are potent candidates for the endocrine
disruptor that binds to ERR-γ.
BIOMONITORS | Human Exposure to Bisphenol A and 4-tertiary-Octylphenol
Bisphenol A (BPA) and 4-tertiary-octylphenol (tOP) are used in the manufacture of polycarbonate plastics and epoxy resins (BPA) and nonionic surfactants (tOP), products that are in widespread use in the United States. To assess exposure to BPA and tOP in the U.S. general population, Calafat et al. (p. 39) measured urinary concentrations of BPA and tOP in participants of the National Health and Nutrition Examination Survey. Concentrations of total BPA differed by race/ethnicity, age, sex, and household income. These urinary BPA and tOP data should help guide public health research priorities, such as studies of exposure pathways, potential health effects, and risk assessment.
RESPIRATORY DISEASE | Fungi, Ergosterol, and Respiratory Illness
Damp building-related respiratory illnesses are an important public health issue. Park et al. (p. 45) compared three respiratory case groups, defined by questionnaire responses, to a comparison group of 152 asymptomatic employees who worked in an office building with a history of water damage. As reported in the literature, mold levels in dust were associated with new-onset asthma in this damp indoor environment. Hydrophilic fungi and ergosterol, as measures of fungal biomass, may have promise as markers of risk of building-related respiratory diseases in water-damaged indoor environments.
RISK ASSESSMENT | Cadmium and Hypertension
Cadmium induces hypertension in animal models, but epidemiologic studies of cadmium exposure and hypertension have been inconsistent. Tellez-Plaza et al. (p. 51) investigated the association of blood and urine cadmium concentrations with blood pressure and with the prevalence of hypertension in U.S. adults who participated in the 1999-2004 National Health and Nutrition Examination Survey. Cadmium levels in blood, but not in urine, were associated with a modest elevation in blood pressure levels. The association was stronger among never-smokers, intermediate among former smokers, and small or null among current smokers.
GENE POLYMORPHISM | Trihalomethane Exposure and Enzyme Polymorphisms
In a previous study, household exposures to tap water were found to increase an individual's internal dose of trihalomethanes (THMs). Backer et al. (p. 57) assessed the importance of personal characteristics, previous exposures, genetic polymorphisms, and environmental exposures in determining THM concentrations in blood after showering. The inclusion of information about individual physiologic characteristics and environmental measurements would be valuable in future studies to assess human health effects from exposures to THMs in tap water.
RISK ASSESSMENT | Dose Response for Particles
Understanding the shape of the concentration-response curve for particles is important for public health; lack of such understanding was recently cited by U.S. Environmental Protection Agency (EPA) as a reason for not tightening the standards. Similarly, the delay between changes in exposure and changes in health is also important in public health decision making. Schwartz et al. (p. 64) addressed these issues using an extended follow-up of the Harvard Six Cities Study, concluding that a reduction in particle concentrations below U.S. EPA standards would increase life expectancy.
REPRODUCTIVE HEALTH | Dioxin, Endocrine Disruption, and Human Sperm Quality
Environmental toxicants have been linked to decreasing semen quality. In 1976, residents in Seveso, Italy, were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) after an explosion at a manufacturing plant. To investigate reproductive hormones and reproductive quality in exposed males, Mocarelli et al. (p. 70) investigated the relationship between serum TCDD concentrations in 1976, and semen quality and reproductive hormones from samples collected 22 years later in males of three age groups at exposure (infancy/prepuberty, puberty, and adulthood) and in a group of healthy comparisons. Exposure during infancy reduces sperm concentration and motility, but an opposite effect is seen in puberty. Exposure in either period leads to permanent reduction of estradiol and increased follicle-stimulating hormone. The effects are permanent and may be partly responsible for the reported decrease in sperm quality, especially in younger men.
EXPOSURE ASSESSMENT | Cognitive Effect of Hydrogen Sulfide
Some epidemiologic studies have reported compromised cognitive and sensory performance among individuals exposed to low concentrations of hydrogen sulfide (H2S). Fiedler et al. (p. 78) hypothesized a dose-response increase in symptom severity and reduction in sensory and cognitive performance in response to controlled H2S exposures. Although some symptoms increased with exposure, the magnitude of these changes were relatively minor. Increased anxiety was significantly related to ratings of irritation due to odor. Whether the effect on verbal learning represents a threshold effect of H2S or an effect due to fatigue across exposure requires further investigation.
Environmental Medicine
CARDIOVASCULAR DISEASE | Asbestos and Calcific Pericarditis
Abejie et al. (p. 86) present the case of a 59-year-old male boiler worker eventually diagnosed with calcific constrictive pericarditis. Based on the patient's history of occupational exposure to asbestos, the presence of pleural pathology consistent with asbestos, and previous evidence that asbestos can affect the pericardium, along with the absence of other likely explanations, the authors concluded that the pericarditis was asbestos-related.
Children's Health
ASTHMA | School Air Pollution and Asthma in Chinese Pupils
There are few studies on associations between children's respiratory heath and air pollution in schools in China. Industrial development and increased traffic may affect the indoor exposure to air pollutants. Studies are also needed on the respiratory effects of environmental tobacco smoke (ETS) and emissions from new building materials in homes. Zhao et al. (p. 90) studied the associations between pupils' asthmatic symptoms and indoor and outdoor air pollution in schools, as well as selected home exposures, in a coal-burning city in China. Indoor chemical air pollutants of mainly outdoor origin could be risk factors for respiratory symptoms at school, and home exposure to ETS and chemical emissions from new furniture could affect pupils' respiratory health.
RESPIRATORY DISEASE | Link between Phthalate Exposure and Allergies
Associations have been identified between the concentration of phthalates in indoor dust and allergic symptoms in the airways, nose, and skin. Kolarik et al. (p. 98) investigated the associations between allergic symptoms in children and the concentration of phthalate esters in settled dust collected from children’s bedrooms in homes in Sofia and Burgas, Bulgaria. The study included 102 children with symptoms of wheezing, rhinitis, and/or eczema in the last 12 months, and 82 nonsymptomatic children. The authors found a dose-response relationship between di(2-ethylhexyl) phthalate (DEHP) concentration and case status and between DEHP concentration and wheezing in the last 12 months.
IMMUNOLOGY | PCB Effects on Thymus Size
Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants, for which animal studies demonstrate immunotoxic effects, including thymic atrophy and suppressed immune responses; however, human studies of similar end points are sparse. The thymus is essential for the differentiation of T-cell lymphocytes. Park et al. (p. 104) examined the association between prenatal PCB exposures and estimated thymus volume in infants from eastern Slovakia, a region where PCBs were produced until 1984. The study provides the first evidence that PCB exposure in neonates is associated with a smaller thymic index, suggesting possible impaired immunologic development.
RISK ASSESSMENT | Air Pollution and Infant Mortality
Woodruff et al. (p. 110) evaluated the relationship between cause-specific postneonatal infant mortality and chronic early-life exposure to particulate matter (PM) and gaseous air pollutants across the United States. The authors linked county-specific monitoring data for particles with aerodynamic diameters of ≥ 2.5 µm (PM2.5) and ≥ 10 µm (PM10), ozone, sulfur dioxide, and carbon monoxide to birth and death records for infants born in U.S. counties with > 250,000 residents during 1999-2002. The study supports PM air pollution as a risk factor for respiratory-related postneonatal mortality and suggests that ozone may be associated with sudden infant death syndrome in the United States.
Mini-Monograph
HEALTH POLICY | Regulatory Science
Scientific evidence plays a crucial role in regulation and law, especially in the area of environmental health. In the courtroom, science helps judges and juries evaluate the disputed facts, and in the regulatory arena, science is also a vital foundation for effective government decision making. The Mini-Monograph (p. 116) explores the nature of scientific knowledge generated for use in the context of litigation or advocacy and discusses whether litigation and regulation-generated studies should be judged by the same standards as those conducted outside the legal and regulatory arenas; how the incentives and intentions that operate in the courtroom and regulatory arenas shape scientific inquiry; and what this implies about the “truth value” of scientific work.
Also see Science Selections, p. A37