Environews
The Life-Long Process of Learning
This month's NIEHS News (p. A806) describes environmental health education opportunities that are offered by the institute across the country. These opportunities reach students of all ages, plus teachers and scientists as well. In other news, stakeholders gather to discuss clinical recommendations and research directions regarding toxic mold exposure, and the NIEHS-sponsored Sister Study is launched nationwide to study how genetic and environmental factors work together to cause breast cancer.
Environmental Health Hits the Books
Efforts are under way around the country to bring environmental health into the classroom, where it can help students grow into informed citizens who can assess and affect important public health issues. But certain elements of our educational system make it hard to include this curricular component. The Focus (p. A814) looks at environmental health as it fits into the current U.S. educational model and tells how a variety of groups are working to connect students with their environments.
Fattening Farms?
Despite attempts to cut back, agricultural support programs are bigger than ever and encouraging farmers to grow ever-greater amounts of wheat, soybeans, and especially corn. Also bigger than ever are Americans' waistlines, thanks in part to widespread consumption of the cheap comestibles made from these crops. The Spheres of Influence (p. A820) looks at agricultural support and subsidy programs and the extent to which supporting farmers in the production of certain crops is helping to spur the U.S. obesity epidemic.
Research
Modified Benchmark Method for BaP Guideline Development
Cancer risk assessment for polycyclic aromatic hydrocarbon (PAH) exposure has been conducted by applying the conservative linearized multistage model to animal tumor data for benzo(a)pyrene (BaP). Fitzgerald et al. (p. 1341) have developed a modified benchmark dose (BMD) method using a suite of conventional mathematical models applied to tumor dose-response data. Mouse tumor data from ingestion of coal tar mixtures call into question the common use of toxicity equivalence factors based on BaP for assessing risk from complex PAH mixtures.
Mitochondrial Perturbation by Aromatic and Polar DEP Chemicals
Particulate pollutants cause adverse health effects through the generation of oxidative stress. A key question is whether these effects are mediated by the particles or by their chemical compounds. Xia et al. (p. 1347) show that aliphatic, aromatic, and polar organic compounds, fractionated from diesel exhaust particles (DEPs), exert differential toxic effects in cells. The chemical effects on isolated mitochondria could be reproduced by intact DEPs as well as by ambient ultrafine particles (UFPs). In contrast, commercial polystyrene nanoparticles failed to exert mitochondrial effects. These results suggest that effects of DEPs and UFPs on the mitochondria permeability transition pore and membrane potential are mediated by adsorbed chemicals instead of by the particles themselves. (Also see Science Selections, p. A824)
Environmental Medicine
Infections and Exposure to OCs in Infants
The Inuit population of Nunavik (Canada) is exposed to immunotoxic organochlorines (OCs) through consumption of fish and marine mammal fat. Dallaire et al. (p.1359) investigated the effect of perinatal exposure to polychlorinated biphenyls (PCBs) and DDE on the incidence of acute infections in Inuit infants. Compared to rates for infants in the first quartile of exposure to PCBs (least exposed), adjusted rate ratios for infants in higher quartiles ranged from 1.17 to 1.27 for all infections combined during the first 6 months of follow-up. The results indicate a possible association between prenatal exposure to OCs and acute infections early in life in this population.
Children's Health
Particulate Air Pollution and Infant Death
Short- and long-term increases in ambient air pollution are associated with increased mortality and morbidity in adults and children. Glinianaia et al. (p. 1365) review the epidemiologic evidence of an association between particulate air pollution and infant mortality. The evidence was generally inconsistent, being reported from locations with largely comparable pollution levels. There is some evidence that the strength of association with particulate matter differed by subgroups of infant mortality.
Drinking Water Nitrate and Methemoglobinemia
It has previously been accepted that consumption of drinking water high in nitrates causes methemoglobinemia in infants. Fewtrell (p. 1371) outlines the investigation of drinking water nitrate concentration and methemoglobinemia based on levels of nitrate in drinking water greater than the World Health Organization guideline value of 50 mg/L. Given the apparent low incidence of possible water-related methemoglobinemia and the complex nature of both the role of nitrates and individual behavior, it is currently inappropriate to attempt to link illness rates with drinking water nitrate levels.
Arsenic on Children's Hands
There are increasing concerns over children's exposure to arsenic from playing on playgrounds built with wood treated with chromated copper arsenate (CCA). Kwon et al. (p. 1375) determined that the mean amount of arsenic on children's hands from CCA playgrounds was significantly higher than the mean amount from non-CCA playgrounds. There was no significant difference in the amount of sand on the children's hands and the concentration of arsenic in the sand between the CCA and non-CCA groups. The maximum amount of arsenic on children's hands from the entire group of study participants was less than the average daily intake of arsenic from water and food. (Also see Science Selections, p. A825)
Effect of Breast Milk Lead on Infant Blood Lead
Ettinger et al. (p. 1381) studied the relationship between maternal breast milk lead and infant blood lead levels among mother-infant pairs. Umbilical cord and maternal blood lead were measured at delivery, and lead levels were measured in maternal blood, bone, and breast milk and in infant blood 1 month after delivery. Infant blood lead level at 1 month postpartum was significantly correlated with umbilical cord and maternal blood lead at delivery, and with maternal blood, patella, and breast milk lead at 1 month postpartum. Although breast milk lead levels were low, they had an influence on infant blood lead levels over and above the influence of maternal blood lead.
Children's VOC Exposures
Adgate et al. (p. 1386) measured exposures to volatile organic compounds (VOCs) in multiple locations for a diverse population of children who attended two inner-city schools in Minneapolis, Minnesota. They measured 15 common VOCs at four locations: outdoors (O), indoors at school (S), indoors at home (H), and in personal (P) samples. Concentrations of most VOCs followed the general pattern O 
S < P 
H across the measured microenvironments. Median and upper-bound H and P exposures were well above health benchmarks for several compounds; therefore, outdoor measurements likely underestimate long-term health risks from children's exposure to these compounds.
Phthalate Exposure Indoors and Allergic Symptoms
Global phthalate ester production has increased to approximately 3.5 million metric tons/year. Bornehag et al. (p. 1393) investigated associations between persistent allergic symptoms in children and the concentration of phthalates in dust collected from their homes using a case-control study nested within a large cohort of children. Results indicate that phthalates, within the range of what is normally found in indoor environments, are associated with allergic symptoms in children. The different associations of symptoms for the three major phthalates may be explained by a combination of chemical physical properties and toxicologic potential.
Fetal Growth and Exposure to Fine Particles in Pregnancy
Jedrychowski et al. (p. 1398) estimated the effects of fine particulate matter (PM2.5) exposure of pregnant women in Poland on birth outcomes. The cohort consisted of pregnant women who gave birth between 34 and 43 weeks of gestation. Measurements of PM2.5 were by personal air monitoring over 48 hr during the second trimester of pregnancy. Predicted reduction in birth weight at an increase of exposure from 10 to 50 mg/m3 was 140.3 g. The corresponding predicted reduction of birth length and head circumference would be 1.0 cm and 0.5 cm, respectively. The study provided new epidemiologic evidence that high personal exposure to fine particles is associated with adverse effects on the developing fetus.
TCDD and Birth Outcomes
Lawson et al. (p. 1403) studied pregnancy outcomes among wives of male chemical workers who were highly exposed to chemicals contaminated with TCDD and among wives of nonexposed neighborhood referents. Neither continuous nor categorical TCDD concentration had an effect on birth weight for term infants after adjustment for infant sex, mother's education, parity, prenatal cigarette smoking, and gestation length. Because the estimated TCDD concentrations in this population were much higher than in other studies, the results indicate that TCDD is unlikely to increase the risk of low birth weight or preterm delivery through a paternal mechanism.
National Environmental Public Health Tracking
The U.S. Centers for Disease Control and Prevention initiated the Environmental Public Health Tracking (EPHT) Program to integrate hazard monitoring and exposure and health effect surveillance into a cohesive tracking network. For such a network to be effective, uniform and acceptable data standards, easily understood case definitions, and improved communication between health and environmental agencies are just a few of the challenges that must be addressed. The Public Health Tracking Mini-Monograph (p. 1409, 1414, 1419, 1424, 1428, 1434, and 1440) presents innovative strategies and methods that are being applied to the broad scope of important and complex environmental public health problems by developing EPHT programs.
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Last Updated: September 20, 2004
