Environews
A Base for Research
Single-nucleotide polymorphisms, or SNPs, are base variants that occur in at least 1% of the population. This month's NIEHS News (p. A390) describes presentations at a recent seminar on gene variation and gene-environment interaction in human health and disease. These presentations explain recent research into SNPs that are associated with illnesses such as leukemia and breast cancer.
What's in Us?
January 2003 saw the release of the Second National Report on Human Exposure to Environmental Chemicals by the Centers for Disease Control and Prevention. The Focus (p. A394) looks at the history of this sometimes-controversial report, discusses some of the more intriguing findings for the 116 chemicals covered, and delves into some of the limitations faced by studies of this type.
Healthy Cities Arise!
From its World Health Organization-sponsored beginnings in 1986 with 25 cities, the Healthy Cities movement has spread to some 8,000 municipalities in every continent except Antarctica. Although their sponsors and workings may vary, programs and networks around the world share the same basic principle, described in the Spheres of Influence (p. A400): the promotion of quality-of-life factors that can help a community of any size improve its social, physical, and cultural environment, and in turn lead to a healthier population.
The Game of Risk
Scientists in the Office of Pollution Prevention and Toxics of the U.S. Environmental Protection Agency will soon release the latest version of the Risk-Screening Environmental Indicators model, described in the Innovations (p. A404). This model gives researchers a new tool for assessing chronic human health risks from industrial pollution exposures for populations living anywhere in the United States.
Research
The Precautionary Principle and Prediction Strategies
Cairns (p. 877) examines human activity and prevention strategies used to plot a course toward sustainable use. The precautionary principle aims to prevent environmental damage before it occurs, whereas natural capitalism and industrial ecology seek to optimize environmental interactions. Prevention continues to be essential, but new tools are needed to move toward optimization. A more holistic approach to the human place within the environment is needed.
Nerve Cell Damage from GSM Mobile Phones
The possible risks of radio-frequency electromagnetic fields for the human body is a concern for society, considering the increase in exposure. Weak pulsed microwaves can cause leakage of albumin through the blood-brain barrier. Salford et al. (p. 881) report that leakage of the blood-brain barrier is combined with damage to the neurons in the cortex, hippocampus, and basal ganglia after exposure to GSM (Global System for Mobile Communications) mobile phone magnetic fields. (Also see Science Selections, p. A408)
OH-PCB Binding to Estrogen Sulfotransferase
Certain hydroxylated polychlorinated biphenyls (OH-PCBs) inhibit human estrogen sulfotransferase (hEST) at subnanomolar concentrations, suggesting a pathway for PCB toxicity from environmental exposure. Shevtsov et al. (p. 884) examined the crystal structure of hEST with the bound OH-PCB and provide physical evidence that certain OH-PCBs can mimic binding of estrogenic compounds in biological systems.
Environmental and Urinary Arsenic in Slovakia
Urinary arsenic was measured as inorganic As (Asinorg), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) and their sum (Assum) in nonmelanoma skin cancer (NMSC) cases and controls in the vicinity of a coal-burning power plant (Ranft et al., p. 889). Persons close to the plant had a 27% higher Assum (p < 0.01). A 32% increase in MMA occurred among subjects with consumption of home-grown food (p < 0.001), and NMSC cases had significantly higher levels of Assum, DMA, and Asinorg.
Retention of MMVF10a in Hamster Lungs
Geiser et al. (p. 895) used electron microscopy to study man-made vitreous fibers (MMVF) 10a in hamster lungs within 23 ± 2 min (mean ± SD) of inhalation. In airways and alveoli, 89% and 32% of the fibers, respectively, were submersed in lining material. Surface balance studies showed that fibers were submersed at approximately 10 mJ/m2 surface tension. Fiber length and alveolar geometry appear to be important limiting factors.
PM-Induced Lung Injury in Healthy Rats
Particulate matter < 2.5 µm (PM2.5) may cause greater adverse effects than PM10. Smith et al. (p. 902) exposed Sprague-Dawley rats to combined fine and ultrafine particles of ambient Fresno (California) PM, enhanced approximately 20-fold over outdoor levels. Viability of recovered bronchoalveolar cells from exposed rats was significantly decreased during 4 of 6 weeks compared with rats exposed to filtered air. (Also see Science Selections, p. A408)
PM Exposure Assessment for Susceptible Populations
Liu et al. (p. 909) examined particulate matter (PM) exposures in individuals with and without chronic obstructive pulmonary disease (COPD), coronary heart disease (CHD), and asthma. PM2.5 (particulate matter < 2.5 µm) exposures varied by cohort, with elderly healthy and CHD subjects having low exposures and asthmatic children having high exposures. PM2.5 exposures among COPD and CHD subjects can be predicted with a three-microenvironment model.
Juvenoids Alter Sex Ratios in Daphnids
Juvenile hormone analog (JHA) insecticides disrupt endocrine-regulated processes unique to insects. To determine if JHAs mimic methyl farnesoate (MF), a crustacean juvenile hormone, Olmstead and LeBlanc (p. 919) exposed Daphnia magna to pyriproxyfen (a JHA), MF, and nonjuvenoid chemicals. Only MF and pyriproxyfen increased the percentage of males produced by exposed maternal organisms. Such an effect in the environment could have dire consequences on susceptible crustacean populations.
Environmental Medicine
Nasal Cytopathology and Diesel Engine Emission
Glück et al. (p. 925) compared nasal cytology of diesel exhaust emission-exposed and -unexposed customs officers twice a year for 5 years. Exposed officers had clear goblet cell hyperplasia with increased metaplastic and dysplastic epithelia and increased leukocytes. There was no evidence of cytopathologic progression. The findings indicate chronic inflammation of the nasal mucous membranes.
Persistent Organic Pollutants and Testicular Cancer
An increase in testicular cancer has been reported during the last decades. One hypothesis is that testicular cancer is initiated during gestation. Hardell et al. (p. 930) investigated the concentrations of 38 persistent organic pollutants (POPs) among mothers of men with testicular cancer and age-matched controls. Certain POPs appeared higher in mothers of patients with testicular cancer, and the etiologic significance warrants further exploration.
Chlorination By-Products and Menstrual Function
Steroid metabolites that define menstrual cycle and phase length were measured daily in urine of premenopausal women during an average of 5.6 cycles (Windham et al., p. 935). The authors estimated a trihalomethane (THM) level for each cycle on the basis of residence measurements and found a decrement in cycle and follicular phase length of 0.18 days (95% confidence interval, -0.29 to -0.07) per 10-µg/L unit increase in THM concentration (the U.S. Environmental Protection Agency's current maximum contaminant level for THM is 80 µg/L). (Also see Science Selections, p. A409)
Children's Health
Disparities in Exposure to Air Pollution during Pregnancy
Poor birth outcomes are associated with minorities and low socioeconomic status. Woodruff et al. (p. 942) suggest that minority mothers may experience more air pollution and are more likely to live in polluted counties. They also observed a small increase in preterm delivery. Poor air quality may exacerbate health problems of children already at increased risk.
Serum Dioxin and Birth Outcome
Eskenazi et al. (p. 947) report on a retrospective cohort study of pregnancy outcome among women who resided in the most TCDD-contaminated areas of Seveso, Italy, during the explosion in 1976. There was no association of log10 TCDD with spontaneous abortion, birth weight, or being small for gestational age. However, the most-exposed women were youngest and least likely to have had a pregnancy.
Organochlorines, Lead, and Mercury in Akwesasne Mohawk Youth
Native American communities may have increased risk of exposure to polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and dichlorophenyldichloroethylene (DDE) due to diet and physical contact with contaminated soil and water. Schell et al. (p. 954) describe levels of PCBs, DDE, HCB, mirex, lead, and mercury among 10- to 17-year-old Akwesasne Mohawk youth. Toxicant levels appear lower than those associated with severe exposure but similar to other chronically exposed groups.
Leukemia and Electric and Magnetic Fields
Epidemiologic studies have reported associations between power-line electric or magnetic fields (EMF) and childhood leukemia. The lack of EMF effects in bioassay systems may be due to how "EMF exposure" is defined and measured. "Contact voltages" have been proposed as a novel exposure metric because their magnitude is related to measured power-line magnetic fields. Any role for contact currents in EMF-leukemia associations will require clarification by further measurements (Brain et al., p. 962).
Mini-Monograph
World Trade Center Respiratory Sequelae
Gavett et al. (p. 971) report results of studies on the chemical properties of the PM2.5 (particulate matter < 2.5 µm) fraction of dust from the destruction of the World Trade Center (WTC) and its toxicity in the respiratory tracts of mice. WTC PM2.5 induced mild to moderate lung inflammation when administered at a high dose (100 mg) into the airways of mice. However, most people would not experience adverse respiratory effects from exposure to even moderately high WTC PM2.5 levels.
Last Updated: May 20, 2003
