Environews
NIEHS NEWS | The Chosen ONES
Future breakthroughs in environmental health science depend upon the recruitment and retention of today's best and brightest scientists. One crucial way of accomplishing this is by providing support that recognizes and encourages innovative projects with the promise of positive impacts on the field. The first of two NIEHS News articles (p. A24) takes a look at the first recipients of the newly established NIEHS Outstanding New Environmental Scientist (ONES) Awards. In other news, the completion of the NIEHS-funded Resequencing and SNP Discovery Project brings a new tool for scientists who study mice as models for human disease.
FOCUS | The Weight of Lead: Effects Add Up in Adults
Recent studies indicate that even relatively low levels of lead exposure can cause adverse health effects. Despite measures implemented over the years to decrease exposure in the general population, some groups, such as those in certain workplaces, still face the possibility of detrimental lead exposure. This article (p. A30) examines current investigations into the long-term, cumulative effects of lead exposure, and discusses scientists' concerns for updated regulatory standards that address the hazards of these exposures.
INNOVATIONS | Beyond Batteries: Portable Hydrogen Fuel Cells
Clean, efficient hydrogen fuel cells continue to garner interest from investigators seeking a convenient and adaptable energy source. Although most applications are still in development and not ready for commercial use, one company in California has successfully harnessed the power of hydrogen fuel cells in a portable format. This article (p. A38) looks at the Jadoo N-Gen™ hydrogen fuel cell system, which offers an alternative to costly and bulky rechargeable battery packs.
Reviews
ETHICS | Source of Funding and Studies of Mobile Phone Use
There is concern regarding the possible health effects of cellular telephone use. Huss et al. (p. 1) examined whether the source of funding of studies on the effects of low-level radiofrequency radiation is associated with the results of studies. Studies funded exclusively by industry reported the largest number of outcomes, but were least likely to report a statistically significant result. This finding was not materially altered in analyses adjusted for the number of outcomes reported, study quality, and other factors. The interpretation of results from studies of health effects of radiofrequency radiation should take sponsorship into account.
NANOTECHNOLOGY | Nanotechnology in the Workplace
In the absence of scientific clarity about the potential health effects of occupational exposure to nanoparticles, a need exists for guidance in decision making about hazards, risks, and controls. Schulte and Salamanca-Buentello (p. 5) identified the ethical issues involved that may be useful to decision makers, particularly employers, workers, investors, and health authorities. Because the goal of occupational safety and health is the prevention of disease in workers, the authors focused on situations that have ethical implications that most affect workers. The ethical issues involve the unbiased determination of hazards and risks, nonmaleficence (doing no harm), autonomy, justice, privacy, and promoting respect for persons.
Research
CARDIOVASCULAR DISEASE | Components of Fine Particles and Mortality in California
Several epidemiologic studies provide evidence of an association between daily mortality and particulate matter < 2.5 µm in diameter (PM2.5). Little is known, however, about the relative effects of PM2.5 constituents. Ostro et al. (p. 13) examined associations between 19 PM2.5 components and daily mortality in six California counties. PM2.5 mass and several constituents were associated with multiple mortality categories, especially cardiovascular deaths. Stronger associations were observed between mortality and additional pollutants, including sulfates and several metals, during the cool season. This multicounty analysis adds to the growing body of evidence linking PM2.5 with mortality and indicates that excess risks may vary among specific PM2.5 components.
HUMAN TOXICOLOGY | PCBs and OH-PCB Metabolites in Slovak Mothers
Park et al. (p. 20) characterized and quantified the levels of polychlorinated biphenyls (PCBs) and specific polychlorobiphenylol (OH-PCB) metabolites in maternal sera from women delivering in eastern Slovakia. PCBs were analyzed using gas chromatography/electron capture detection. OH-PCBs and pentachlorophenol were determined as methyl derivatives using gas chromatography-electron capture negative ionization/mass spectrometry. Mothers residing in eastern Slovakia are highly exposed to PCBs, and their body burdens of these pollutants and OH-PCB metabolites may pose a risk for adverse effects on health for themselves and their children.
BIOMARKERS | Albumin Adducts of Benzene Metabolites
Metabolism of benzene produces reactive electrophiles, including benzene oxide (BO), 1,4-benzoquinone (1,4-BQ), and 1,2-benzoquinone (1,2-BQ), that are capable of reacting with blood proteins to produce adducts. Lin et al. (p. 28) characterized relationships between levels of albumin adducts of these electrophiles in blood and the corresponding benzene exposures in benzene-exposed and control workers, after adjusting for important covariates. Although albumin adducts of BO and the benzoquinones reflect exposures to benzene ≥ 1 ppm, they would not be useful biomarkers of exposure at ambient levels of benzene, which tend to be < 0.01 ppm, or in those working populations where exposures are consistently < 1 ppm.
POLYMORPHISM | ALAD Polymorphism and Lead: A Meta-Analysis
Lead poisoning affects many organs in the body, and lead inhibits 
-aminolevulinic acid dehydratase (ALAD), an enzyme with two co-dominantly expressed alleles, ALAD1 and ALAD2. Scinicariello et al. (p. 35) studied the effects of the ALAD polymorphism on blood and bone lead levels (BLL) and on indicators of target organ toxicity. Carriers of the ALAD2 allele had lower zinc protoporphyrin, higher hemoglobin, and higher BLLs than those who were ALAD1 homozygous. Effects on other organs were not well delineated, partly because of the small number of subjects studied and the potential modifications caused by other proteins in target tissues or by other polymorphic genes.
RISK ASSESSMENT | Fish Consumption, Mercury, and Preterm Delivery
Pregnant women receive mixed messages about fish consumption in pregnancy because unsaturated fatty acids and protein in fish are thought to be beneficial, but contaminants such as methylmercury may pose a hazard. Xue et al. (p. 42) used the Pregnancy Outcomes and Community Health study, where women were enrolled in the 15th to 27th week of pregnancy through 52 prenatal clinics in five Michigan communities. This is the first large, community-based study to examine risk of very preterm birth in relation to mercury levels among women with low to moderate exposure. Additional studies are needed to see whether these findings will be replicated in other settings.
Also see Science Selections, p. A43
IMMUNOLOGY | Environmental Estrogens Enhance Mast Cell Degranulation
Prevalence and morbidity of allergic diseases have increased over the last decades. Based on the recently recognized differences in asthma prevalence between the sexes, Narita et al. (p. 48) examined the effect of endogenous estrogens on a key element of the allergic response. Some lipophilic pollutants have estrogen-like activities. These pollutants tend to degrade slowly in the environment and bioaccumulate and bioconcentrate in the food chain; they also have long biological half-lives. The findings suggest that estrogenic environmental pollutants might promote allergic diseases by inducing and enhancing mast cell degranulation by physiologic estrogens and exposure to allergens.
CARDIOVASCULAR DISEASE | Long-Term Exposure to Traffic and AMI
Long-term exposure to particulate air pollution has been associated with an increased risk of dying from cardiopulmonary and ischemic heart disease, yet few studies have evaluated cardiovascular end points other than mortality. Tonne et al. (p. 53) investigated the relationship between long-term exposure to traffic and occurrence of acute myocardial infarction (AMI) in a case\–control study. An increase in cumulative traffic near the home was associated with a 4% increase in the odds of AMI per interquartile range, whereas living near a major roadway was associated with a 5% increase in the odds of AMI per kilometer.
Also see Science Selections, p. A42
INFECTIOUS DISEASE | Tracking Patterns of Enteric Illnesses
Enteric illness arising from contaminated water and food is a major health concern worldwide, and tracking the incidences and severity of outbreaks is a challenging task. In most developed and developing countries, administrative databases maintained by the government and/or health insurance authorities are used to record medical visits and services. Peace and Mazumder (p. 58) used the Medical Services Plan (MSP) database to develop innovative ways to track long-term patterns of enteric illness at the level of populations and communities. As diagnostic code and fee item data for medical services are collected, their method can have global applications for tracking enteric and other illnesses.
NEURODEVELOPMENT | Developmental Neurotoxicity of Organophosphates
Organophosphate pesticides affect mammalian brain development through mechanisms separable from the inhibition of acetylcholinesterase (AChE) enzymatic activity and resultant cholinergic hyperstimulation. AChE has two catalytically similar splice variants with distinct functions in development and repair. The rare read-through isoform, AChE-R, is preferentially induced by injury and appears to promote repair and protect against neurodegeneration. Overexpression of the more abundant synaptic isoform, AChE-S, enhances neurotoxicity. Jameson et al. (p. 65) indicate that nonenzymatic functions of AChE variants may participate in and be predictive of the relative developmental neurotoxicity of organophosphates, and that the various organophosphates differ in the degree to which they activate this mechanism.
EXPOSURE ASSESSMENT | PBDEs in Pregnant Latina Women
Recent studies have raised concerns about exposures to polybrominated diphenyl ether (PBDE) flame retardant in pregnant women and women of child-bearing age in the United States, but few studies have measured PBDEs in immigrant populations. Bradman et al. (p. 71) characterized levels of seven PBDE congeners, polychlorinated biphenyl (PCB)-153, and polybrominated biphenyl-153 in 24 pregnant women of Mexican descent living in an agricultural community in California. The overall levels of PBDEs found were lower than those observed in other U.S. populations, although still higher than those observed previously in Europe or Japan. The upper range of exposure is similar to what has been reported in other U.S. populations.
EPIDEMIOLOGY | Diabetes and Hazardous Waste Sites
Epidemiologic studies suggest that there may be an association between environmental exposure to persistent organic pollutants (POPs) and diabetes. Kouznetsova et al. (p. 75) tested the hypothesis that residential proximity to POP-contaminated waste sites result in increased rates of hospitalization for diabetes. The authors determined the number of hospitalized patients diagnosed with diabetes in New York State, exclusive of New York City, for the years 1993\–2000. After controlling for major confounders, they found a statistically significant increase in the rate of hospitalization for diabetes among the population residing in the ZIP codes containing toxic waste sites.
CARCINOGENESIS | BPA Exposure and Cancer Risk
Humans are routinely exposed to bisphenol A (BPA), an estrogenic compound that leaches from dental materials, food and beverage containers, and other consumer products. Prenatal exposure to BPA has produced long-lasting and profound effects on rodent hormone-dependent tissues that are manifested 1\–6 months after the end of exposure. Durando et al. (p. 80) examined whether in utero exposure to BPA alters mammary gland development and increases its susceptibility to the carcinogen N-nitroso-N-methylurea (NMU). Prenatal exposure to low doses of BPA perturbs mammary gland histoarchitecture and increases the carcinogenic susceptibility to a chemical challenge administered 50 days after the end of BPA exposure.
MUTAGENESIS | Mutagenicity of Asbestos in the Transgenic gpt Assay
Genotoxicity is often a prerequisite to the development of malignancy. Considerable evidence has shown that exposure to asbestos fibers results in the generation of chromosomal aberrations and multilocus mutations. However, there is less evidence to demonstrate the contribution of deletions to the mutagenicity of asbestos fibers. Xu et al. (p. 87) investigated the mutation fractions and the patterns induced by chrysotile fibers in gpt delta transgenic mouse primary embryo fibroblasts. The results provide novel information on the frequencies and types of mutations induced by asbestos fibers in the gpt delta transgenic mouse mutagenic assay, which shows great promise for evaluating fiber/particle mutagenicity.
BIOSENSORS | Screening for Developmental Neurotoxicity
In light of the large number of chemicals that are potential developmental neurotoxicants, there is a need to develop rapid screening techniques. Slotkin et al. (p. 93) exposed undifferentiated and differentiating neuronotypic PC12 cells to different organophosphates, a carbamate, an organochlorine, and a metal and examined indices of cell replication and differentiation for both short- and long-term exposures. The study points out the feasibility of developing cell-based screening methods that enable the detection of multiple end points that may relate to mechanisms associated with developmental neurotoxicity, revealing some common targets for disparate agents.
INFECTIOUS DISEASE | Potential Risks of Widespread Tamiflu Use
The threat of pandemic influenza has focused attention and resources on virus surveillance, prevention, and containment. The World Health Organization has recommended the use of the antiviral drug Tamiflu both to treat and to prevent pandemic influenza infection. A major concern for the long-term efficacy of this strategy is the limitation of the development of Tamiflu-resistant influenza strains. However, in the event of a pandemic, hundreds of millions of courses will be rapidly deployed. Given its apparent resistance to biodegradation and hydrophilicity, oseltamivir carboxylate, the active antiviral and metabolite of Tamiflu, is predicted by Singer et al. (p. 102) to enter receiving river water from sewage treatment works in its active form.
Also see Science Selections, p. A42
Environmental Medicine
RISK CHARACTERIZATION | Toxic Hepatitis in Industrial Waste Disposal Workers
Cheong et al. (p. 107) report on five workers in an industrial waste plant who developed acute toxic hepatitis after working in the high-vapor-generating area of the plant. The workers had been exposed to several chemicals with hepatotoxic potential, including pyridine, dimethylformamide, dimethylacetamide, and methylenedianiline. The authors recommend that industrial waste, changes to the disposal process, and addition of chemicals should all be monitored and controlled carefully in the industrial waste industry to reduce the health hazard to workers. A mixture of hepatotoxic chemicals can induce clinical manifestations that are quite different from those predicted by the toxic property of a single agent.
NEURODEGENERATIVE DISEASE | LHON and Exposure to Solvents
Leber hereditary optic neuropathy (LHON) is a maternally inherited loss of central vision related to pathogenic mutations in the mitochondrial genome. These mutations are necessary but not sufficient for developing the disease. Carelli et al. (p. 113) report on the case ofa 27-year-old man (a moderate smoker) who developed an optic neuropathy after a 6-month period of occupational exposure to n-hexane and other organic solvents. The patient suffered a sequential optic neuropathy with the hallmarks of LHON and tested positive for the homoplasmic 11778G > A/ND4 mutation. Ina subject carrying an LHON mutation, the strict temporal sequence of prolonged appreciable occupational exposure followed by sudden onset of visual loss must raise a suspicion of causality.
Children's Health
BIOMARKERS | Urinary Environmental Biomarkers in Girls
Hormonally active environmental agents have been measured among U.S. children using exposure biomarkers in urine. However, little is known about their variation by race, age, sex, and geography, and no data exist for newly developed biomarkers. Wolff et al. (p. 116) characterized relevant, prevalent exposures for a study of female pubertal development. Participants represented four racial/ethnic groups (Asian, black, Hispanic, white), with a mean age of 7.77 years. Several hormonally active exposure biomarkers were detectable and variable among young girls, with high maximal concentrations found for several analytes. They varied by characteristics that may be relevant to development.
Also see Science Selections, p. A43
NEUROBEHAVIORAL DISEASE | Manganese in Water and Hyperactivity in Children
Neurotoxic effects are known to occur with inhalation of manganese particulates, but little is known about exposure to Mn in water. Bouchard et al. (p. 122) carried out a pilot study in a community in Quebec, Canada, where naturally occurring high Mn levels were present in the public water system. The authors tested the hypothesis that greater exposure to Mn via drinking water would be reflected in higher Mn content in hair, which, in turn, would be associated with an increase in hyperactive behaviors. The findings of this pilot study are sufficiently compelling to warrant more extensive investigations into the risks of Mn exposure in drinking water.
NEUROBEHAVIORAL DISEASE | Neurobehavioral Development in Ecuador
Handal et al. (p. 128) compared neurobehavioral development in Ecuadorian children living in two communities with high potential for exposure to organophosphate (OP) and carbamate pesticides to that of children living in a community with low potential for exposure. Children residing in the high-exposure communities scored significantly lower on motor skills than children of similar ages residing in the low-exposure community. Residence in communities with high potential for exposure to OP and carbamate pesticides was associated with poorer neurobehavioral development of the child, even after controlling for major determinants of delayed development. Malnourished populations may be particularly vulnerable to neurobehavioral effects of pesticide exposure.
RISK ASSESSMENT | Pesticides and Wilms Tumor
Previous epidemiologic studies have suggested that exposure to pesticides in utero and during early childhood may increase the risk for development of childhood cancer, including Wilms tumor, a childhood kidney tumor. Cooney et al. (p. 134) used data from a North American case\–control study to evaluate the role of residential pesticide exposure in relation to the risk of Wilms tumor in children. The authors were unable to confirm earlier reports of an increased risk for Wilms tumor among those exposed to residential pesticides during pregnancy through early childhood.
Mini-Monograph
CANCER | Acute Leukemia in Children
To address both the needs of state health departments and public concern, the Centers for Disease Control and Prevention (CDC) now provides a centralized, coordinated response system for cancer cluster inquiries; supports an electronic cancer cluster listserver; maintains an informative web page; and provides support to states, ranging from laboratory analysis to epidemiologic assistance and expertise. The Mini-monograph (p. 138) examines the etiology of childhood leukemia through the study of cancer clusters, focusing on the demographics of childhood leukemia and the risk factors associated with its development; these include risk factors include genetic factors, maternal reproductive history, infectious agents, and environmental risk factors, such as ionizing radiation, nonionizing radiation, hydrocarbons, pesticides, alcohol use, cigarette smoking, and illicit drug use. Knowledge of these particular risk factors can be used to support measures to reduce potentially harmful exposures and decrease the risk of disease. Response to cancer clusters is appropriate public health action, and the CDC will continue to provide assistance, facilitate communication among states, and foster the development of new approaches in cluster science.
