In This Issue

Environews

FOCUS | The Yuck Factor: When Disgust Meets Discovery

Our instinct protects us from harm, often leading us to avoid threats without fully understanding why. But what happens when the instinct to recoil overrides acceptance of potentially beneficial technologies? This article (p. A524) explores how the so-called yuck factor can influence people's view of scientific innovations and how scientists can better understand the powerful influence of public perception.

SPHERES OF INFLUENCE | Does One Size Fit All? Small Farms and U.S. Meat Regulations

Food recalls and a growing awareness of the environmental impact of food production have prompted a growing number of consumers to seek out local farms with the hopes of finding safer, more sustainably grown meat products. But some small farm owners are finding it difficult to operate successfully while complying with federal requirements for food inspections and safety. This article (p. A528) discusses strategies being developed to simplify compliance requirements for smaller farming operations.

Review

INFECTIOUS DISEASE | Climatic, Social, and Environmental Factors and Ross River Virus

Arboviral diseases have emerged as a global public health concern. The most common and widespread arboviral disease in Australia is Ross River virus (RRV). Tong et al. (p. 1591) reviewed the interrelationship between climatic, social, and environmental factors and the transmission of RRV. They found that rainfall, temperature, and high tides were among major determinants of the transmission of RRV disease at the macro level. However, the nature and magnitude of the interrelationship between climate variability, mosquito density, and the transmission of RRV disease varied with geographic area and socioenvironmental condition.

POPULATION HEALTH | Comparative Analysis of State Fish Advisories

Fish consumption advisories are issued to warn the public of possible toxicologic threats from consuming certain fish species. Formulating advice for sensitive populations poses challenges because developing fetuses and children are particularly susceptible to toxicants in fish, but fish contains valuable nutrients. Scherer et al. (p. 1598) conducted a comparative analysis of advisory Web sites issued by states to assess health messages that might be accessed by sensitive populations. Most states do present information about benefits of consuming fish in addition to the risks, but advisories may inadvertently cast a dim light on all fish consumption. Ideally, from a public health perspective, sensitive populations should receive clear, sufficiently explained health messages regarding fish consumption that aim to optimize both maternal and fetal health by decreasing risks and increasing benefits.

Research

NANOTECHNOLOGY | Acute Toxicity of Quantum Dots in Mice

Quantum dots (QDs) have many possible applications for in vivo imaging, but toxicity data are scarce. Geys et al. (p. 1607) determined the acute in vivo toxicity of QDs with carboxyl surface coating (carboxyl-QDs) and QDs with amine surface coating (amine-QDs), and investigated the inflammatory properties, tissue distribution, and prothrombotic effects after intravenous injection. At high doses, QDs caused pulmonary vascular thrombosis, most likely by activating the coagulation cascade via contact activation. This study highlights the need for careful safety evaluation of QDs before their use in human applications. Furthermore, it is clear that surface charge is an important parameter in nanotoxicity.

AGING | Mortality Risks from Chronic Exposure to Fine Particulate Matter

Prospective cohort studies constitute the major source of evidence about the mortality effects of chronic exposure to particulate air pollution; however, few studies on the health effects of chronic exposure to particulate matter ≤ 2.5 µm in aerodynamic diameter (PM_2.5) have been carried out, and the cohorts have not been representative. Zeger et al. (p. 1614) established a cohort of Medicare participants to investigate the relative risk of death associated with long-term exposure to PM_2.5 by region and age group in elderly subjects. Chronic exposure to PM_2.5 was associated with mortality in the eastern and central regions, but not in the western United States.

RISK ASSESSMENT | Mortality and Changes in Internal Cadmium Exposure

Nawrot et al. (p. 1620) monitored blood cadmium, 24-hr urinary cadmium, and mortality in an environmentally exposed population. The authors found that environmental exposure to cadmium increases the risk of death. Environmental exposure to cadmium increases total and noncardiovascular mortality in a continuous fashion, with no threshold. Even if zinc–cadmium smelters close, historical environmental contamination remains a persistent source of exposure.

EXPOSURE SCIENCE | Human PBPK Model for Lactational Transfer of PCB-153

Redding et al. (p. 1629) developed a physiologically based pharmacokinetic model of PCB-153 in women and predicted its transfer via lactation to infants. They used used physiologic parameters from a cohort in Taiwan and reference values from the literature to estimate partition coefficients based on chemical structure and the lipid content in various body tissues. Using exposure data from Japan, the authors predicted acquired body burden of PCB-153 at an average childbearing age of 25 years and compared predictions to measurements from studies in multiple countries. The model successfully described the range of possible PCB-153 dispositions in maternal milk, suggesting a promising option for back-estimating doses for various populations and for other PCBs.

Also see Science Selections, p. A532

ENDOCRINE SYSTEM | PBDEs and Hormones in Adult Males

Polybrominated diphenyl ethers (PBDEs), used as flame retardants, are similar in structure to polychlorinated biphenyls (PCBs), which affect endocrine function. Turyk et al. (p. 1635) investigated whether PBDE body burdens are related to thyroid and steroid hormone levels, thyroid antibodies, and thyroid disease in a cohort of frequent and infrequent adult male sport fish consumers. The authors found that PBDE exposure, at levels comparable with those of the general U.S. population, was associated with increased thyroglobulin antibodies and increased thyroxine in adult males.

Also see Science Selections, p. A532

OBESITY | Inhibition of Adiponectin Release by Bisphenol A

The incidence of obesity, which has risen dramatically over the last few decades, may be affected by exposure to xenobiotic chemicals such as bisphenol A (BPA), an endocrine disruptor detectable at nanomolar levels in human serum worldwide. Any factor that suppresses the release of adiponectin (an adipocyte-specific hormone that increases insulin sensitivity and reduces tissue inflammation) could lead to insulin resistance and increased susceptibility to obesity-associated diseases. Hugo et al. (p. 1642) compared the effects of low doses of BPA and estradiol on adiponectin secretion and the expression of putative estrogen and estrogen-related receptors. BPA, at environmentally relevant doses, inhibits the release of a key adipokine that protects humans from metabolic syndrome.

Also see Science Selections, p. A533

GENE EXPRESSION | Atrazine Action in Ovarian Cancer Cells

Atrazine, one of the most common pesticide contaminants, up-regulates aromatase activity in certain estrogen-sensitive tumors without binding or activating the estrogen receptor (ER). The orphan G-protein–coupled receptor 30 (GPR30), which is structurally unrelated to the ER, has been shown to mediate rapid actions of 17β-estradiol and environmental estrogens. Given the ability of atrazine to exert estrogen-like activity in cancer cells, Albanito et al. (p. 1648) evaluated the potential of atrazine to signal through GPR30 in stimulating biologic responses in cancer cells. The authors found that atrazine stimulates gene expression and growth effects in estrogen-sensitive ovarian cancer cells through GPR30 and the involvement of ERα.

BIOMONITORS | Arsenic Species in Exfoliated Bladder Cells

The concentration of arsenic in urine has been used as a marker of exposure to inorganic As (iAs), but the adverse effects of iAs exposure are ultimately determined by the concentrations of iAs metabolites in target tissues. Hernández-Zavala et al. (p. 1656) examined the feasibility of analyzing As species in cells that originate in the urinary bladder, a target organ for As-induced cancer in humans. Results suggest that urinary levels of iAs metabolites do not necessarily reflect levels of these metabolites in the bladder epithelium. Analysis of As species in exfoliated bladder epithelial cells may provide a more effective tool for risk assessment of bladder cancer and other urothelial diseases associated with exposures to iAs.

RISK ASSESSMENT | Inhaled Arsenic and Respiratory Cancer Mortality

Inhalation of high levels of airborne inorganic arsenic (iAs) is a recognized cause of respiratory cancer. Lubin et al. (p. 1661) investigated the shape of the relationship between respiratory cancer mortality and cumulative inhaled As exposure among copper smelter workers, and the modification of that relationship by As. Results suggest a direct concentration effect from inhaled iAs, whereby the excess relative risk for a fixed cumulative exposure is greater when delivered at a higher concentration and shorter duration than when delivered at a lower concentration and longer duration.

CARDIOVASCULAR DISEASE | Air Pollution and Endothelial Function in Diabetic Individuals

Exposure to fine airborne particulate matter [aerodynamic diameter ≤ 2.5 µm (PM_2.5)] has been associated with cardiovascular and hematologic effects, especially in older people with cardiovascular disease. Some epidemiologic studies suggest that adults with diabetes also may be a particularly susceptible population. Schneider et al. (p. 1666) analyzed the short-term effects of ambient PM_2.5 on markers of endothelial function in diabetic volunteers. Results indicated that PM_2.5 exposure may cause immediate endothelial dysfunction. Clinical characteristics associated with insulin resistance were associated with enhanced effects of PM on endothelial function, and participants with greater oxidative potential seem to be more susceptible.

CANCER | Mortality from Mesothelioma, Asbestos Use, and Bans

Nishikawa et al. (p. 1675) assessed national experiences of recent mortality from pleural mesothelioma, historical trends in asbestos use, adoption of bans, and their possible interrelationships for 31 countries with available data. They found that period mortality rates increased in five countries, with marginal significance in two countries, and were equivocal in 24 countries. Countries adopting asbestos bans reduced use rates about twice as fast as those not adopting bans. The observed disparities in global mesothelioma trends likely relate to country-to-country disparities in asbestos use trends.

EXPOSURE SCIENCE | Residential Use of Permethrin and Piperonyl Butoxide

Widespread residential pesticide use throughout the United States has resulted in ubiquitous, low-level pesticide exposure. In response to 2000–2001 regulations restricting use of the organophosphorus insecticides chlorpyrifos and diazinon, the mix of active pesticide ingredients is changing. Williams et al. (p. 1681) investigated the impact of U.S. Environmental Protection Agency regulations on pest infestation levels, pesticide use, and pesticide concentrations measured in indoor air samples. In a cohort of 511 pregnant women from inner-city New York, New York, the authors found that pest infestations, use of pesticides, and use of permethrin appeared to increase after the residential restriction of organophosphorus insecticides.

Also see Science Selections, p. A533

DNA REPAIR | DNA Damage in Workers Exposed to Vanadium Pentoxide

Inhalative exposure to vanadium pentoxide (V₂O₅) causes lung cancer in rodents. Ehrlich et al. (p. 1689) investigated the impact of V₂O₅ on DNA stability in workers from a V₂O₅ factory. Seven of eight biomarkers were increased in blood cells of the workers, and vanadium plasma concentrations in plasma were 7-fold higher than in the controls. They determined DNA strand breaks in leukocytes and investigated different parameters of chromosomal instability in lymphocytes from workers and controls. The authors concluded that V₂O₅ causes oxidation of DNA bases, affects DNA repair, and induces formation of micronuclei, nucleoplasmic bridges, and nuclear buds in blood cells, suggesting that the workers are at increased risk for cancer and other diseases related to DNA instability.

GENE REGULATION | PBDEs Disrupt Thyroid-Regulated Gene Transcription

Polybrominated diphenyl ether (PBDE) flame retardants have been implicated as disruptors of the hypothalamic–pituitary–thyroid axis. Lema et al. (p. 1694) examined the effects of dietary exposure to 2,2´,4,4´-tetrabromodiphenyl ether (PBDE-47) on plasma thyroid hormone (TH) levels and on gene transcripts for glycoprotein hormone α-subunit (GPHα) and thyrotropin β-subunit (TSHβ) in the pituitary gland, the autoinduced TH receptors α and β in the brain and liver, and the TH-responsive transcription factor basic transcription element-binding protein in the brain. Results indicate that dietary exposure to PBDE-47 alters TH signaling at multiple levels of the hypothalamic–pituitary–thyroid axis and provide evidence that TH-responsive pathways in the brain may be particularly sensitive to disruption by PBDE flame retardants.

EXPOSURE SCIENCE | Human Evidence in Quantitative Risk Assessment

Careful evaluation of the quality of human observational studies (HOS) is required to assess the suitability of HOS for quantitative risk assessment (QRA). In particular, the quality of quantitative exposure assessment is a crucial aspect of HOS to be considered for QRA. Vlaanderen et al. (p. 1700) developed guidelines for the evaluation of HOS for QRA and applied these guidelines to case–control and cohort studies on the relation between exposure to benzene and acute myeloid leukemia. Their guidelines facilitate a structured evaluation that is transparent in its application and harmonizes the evaluation of HOS for QRA.

ENVIRONMENTAL TOXICOLOGY | Methylmercury in Marine Ecosystems

Mercury and other contaminants in coastal and open-ocean ecosystems are an issue of great concern globally and in the United States, where consumption of marine fish and shellfish is a major route of human exposure to methylmercury (MeHg). Chen et al. (p. 1706) report on a recent workshop that brought together human health experts, marine scientists, and ecotoxicologists to encourage cross-disciplinary discussion between ecosystem and human health scientists and to articulate research and monitoring priorities to better understand how marine food webs have become contaminated with MeHg. The authors concluded that the current understanding of Hg in marine ecosystems across a range of habitats, chemical conditions, and ocean basins is severely data limited; an integrated research and monitoring program is needed to link the processes and mechanisms of MeHg production, bioaccumulation, and transfer with MeHg exposure in humans.

Environmental Medicine

NEUROBEHAVIORAL DISEASE | Depression and Pesticides in Farmer Applicators

Beseler et al. (p. 1713) evaluated the relationship between diagnosed depression and pesticide exposure using information from private pesticide applicators enrolled in the Agricultural Health Study in Iowa and North Carolina. The study included 534 cases who self-reported physician-diagnosed depression and 17,051 controls who reported never having been diagnosed with depression and not feeling depressed more than once a week in the past year. Based on questionnaire data from this well-defined agricultural cohort, high cumulative exposure in the absence of an unusually high pesticide exposure event (HPEE) or pesticide poisoning, as well as a history of either HPEE or physician-diagnosed pesticide poisoning, was significantly associated with physician-diagnosed depression.

Children's Health

HEALTHY POLICY | Addressing Children's Health through Regulatory Policy

Executive Order (EO) 13045, "Protection of Children from Environmental Health Risks and Safety Risks," directs each federal agency to ensure that its policies, programs, activities, and standards address disproportionate environmental health and safety risks to children. Payne-Sturges and Kemp (p. 1720) reviewed regulatory actions published by the U.S. Environmental Protection Agency (EPA) to evaluate the actions and consideration of children's health issues in U.S. EPA rule making. Although virtually all actions reviewed discussed EO 13045, fewer than two regulations per year were subject to the EO requirement to evaluate children's environmental health risks. Nonetheless, the U.S. EPA considered children's environmental health in all actions addressing health or safety risks that may disproportionately affect children.

ASTHMA | Impact of Chronic Ambient Ozone on Asthma Hospitalizations

Lin et al. (p. 1725) investigated the impact of chronic exposure to high ozone levels on childhood asthma admissions in New York State. They identified births and asthma admissions through the New York State Integrated Child Health Information System, and the data were linked with ambient ozone data from the New York State Department of Environmental Conservation. The authors found that chronic exposure to ambient ozone may increase the risk of asthma admissions among children and that younger children and those in low socioeconomic groups have a greater risk of asthma than do other children at the same ozone level.

FETAL DEVELOPMENT | Nuclear Bomb Test Plutonium in Children

Occupational risks, nuclear threats, and the potential danger associated with nuclear power have raised concerns regarding the metabolism of plutonium in pregnant women. To investigate the transfer of plutonium from the mother's blood plasma to the fetus, Froidevaux and Haldimann (p. 1731) measured plutonium levels in the deciduous teeth of Swiss children born between 1951 and 1995. The researchers used deciduous teeth because the enamel is formed during pregnancy. Results showed that the plutonium found in deciduous teeth was caused by fallout inhaled around the time the teeth were shed and not from any accumulation during pregnancy through placental transfer. Thus, plutonium may not represent a radiologic risk for the radiosensitive tissues of the fetus.

ENVIRONMENTAL JUSTICE | A Highly Spatially Resolved Childhood Lead Exposure Risk Model

Geographic information system–based childhood lead exposure risk models, especially if executed at highly resolved spatial scales, can help identify children most at risk of lead exposure, as well as prioritize and direct housing and health-protective intervention programs. However, developing highly resolved spatial data requires labor- and time-intensive geocoding and analytical processes. Kim et al. (p. 1735) evaluated the benefits of increased effort spent geocoding in terms of improved performance of lead exposure risk models. The models performed well enough to identify high-risk areas for targeted intervention, even with a relatively low level of effort on geocoding.