Environews
Population Perceptions
This month's NIEHS News (p. A550) looks at the work of the Center for Environmental Health and Susceptibility at the University of North Carolina at Chapel Hill. Center scientists are studying the fundamental processes that contribute to chemical toxicity, especially in genetically susceptible populations.
The Nitrogen Cycle: A World of Change
In the quest to produce more food, and with the rise of the combustion engine, humans have manipulated nitrogen to the point that the global nitrogen cycle has been altered more than any other basic element cycle. The Focus (p. A556) investigates the effects of this alteration, both beneficial and disastrous, on human and ecological health.
Feather Fibers for Circuit Boards
The Innovations (p. A564) describes research into using waste feathers from the poultry industry to make a new and improved circuit board. The fibrous keratin in feathers is light, tough enough to withstand mechanical and thermal stresses, and of very low density, providing strength without sacrificing weight. The result may one day be a computer circuit board that gives a whole new meaning to the term "hunt and peck."
Research
Effect Measures in Prevalence Studies
In the debate about the appropriate methods for prevalence studies, recent articles have argued that prevalence ratios are the preferred method and that prevalence odds ratios should not be used. Pearce (p. 1047) discusses the differences between the methods and argue that prevalence odds ratios will continue to be one of the standard methods for analyzing prevalence studies and prevalence case-control studies.
PCB Contamination in Schools and Other Buildings
Investigation of 24 buildings in the Greater Boston Area revealed that one-third contained caulking materials with polychlorinated biphenyl (PCB) content exceeding 50 ppm by weight, the U.S. Environmental Protection Agency limit above which this material is considered PCB bulk product waste. Current regulations do not require that materials such as caulking be tested for PCB content. Herrick et al. (p. 1051) suggest that this testing would detect many buildings that contain high levels of PCB in the building materials, and potentially in the building environment.
Atrazine-Mediated Survival in Larval Amphibians
Amphibians can be exposed to contaminants via agricultural runoff in amphibian breeding sites. Storrs and Kiesecker (p. 1054) exposed tadpoles of four species of frogs--spring peepers (Pseudacris crucifer), American toads (Bufo americanus), green frogs (Rana clamitans), and wood frogs (Rana sylvatica)--at early and late developmental stages to a commercial preparation of atrazine at 3, 30, or 100 ppb. Survival was lower for all animals exposed to 3 ppb compared with those exposed to either 30 or 100 ppb, except for the late stages of B. americanus and R. sylvatica.
Fullerenes Cause Oxidative Damage in Largemouth Bass
Although nanotechnology has vast potential, it is likely that nanomaterials can impact wildlife if they are accidentally released into the environment. Fullerenes, one type of manufactured nanoparticle, can form aqueous suspended colloids (nC60). They are lipophilic, they localize into lipid-rich regions such as cell membranes in vitro, and they are redox active. Oberdörster (p. 1058) reports significant lipid peroxidation in the brain of largemouth bass after a 48-hr exposure to 0.5 ppm uncoated nC60. (Also see Science Selections, p. A568)
Submicrometer Particles and Heart Rate Variability
Chan et al. (p. 1063) studied young adults and elderly patients with lung function impairments in order to evaluate whether submicrometer particulate air pollution was associated with heart rate variability (HRV). Electrocardiography and personal exposure to number concentrations of submicrometer particles with a size range of 0.02-1 µm (NC0.02-1) were measured continuously during the daytime. For both groups, exposure to NC0.02-1 was associated with decreases in both time-domain and frequency-domain HRV.
Gastrointestinal Effects and Copper Exposure
Araya et al. (p. 1068) assessed gastrointestinal effects of exposure to either < 0.01 (controls), 2, 4, or 6 mg copper/L of drinking water for 2 months in a randomized, double-blind, community-based study. Risk of symptoms increased with increasing copper exposure and decreased with time. Exposure to copper in drinking water results in gastrointestinal symptoms, which are modulated by copper concentration, time, and sex. (Also see Science Selections, p. A568)
Loggerhead Sea Turtle Health and Contaminants
Persistent organochlorine (OC) contaminants have broad-ranging toxicities in wildlife. Keller et al. (p. 1074) investigated possible health effects of OCs on loggerhead sea turtles (Caretta caretta). Nonlethal fat biopsies and blood samples were collected from live turtles for OC contaminant analysis, and concentrations were compared to clinical health data, including hematology, plasma chemistry, and body condition. Several positive correlations suggest that OC contaminants are affecting the health of loggerhead sea turtles, even though sea turtles accumulate lower concentrations of OCs compared with other wildlife.
Plasma DDE and Immunologic Measures
Rodent studies suggest immunosuppressive effects of dietary exposure to DDT, but human data are limited. Cooper et al. (p. 1080) examined the association between the organochlorine breakdown product 1,1-dichloro-2,2,bis(p-chlorophenyl)ethylene (p,p´-DDE) and immunologic measures using blood samples in a relatively highly exposed population of farmers. IgG levels decreased with increasing p,p´-DDE levels, and the prevalence of antinuclear antibodies was somewhat elevated in the highest category of p,p´-DDE exposure. These analyses provide evidence that p,p´-DDE modulates immune responses in humans.
Contaminants in U.K. Breast Milk, 2001-2003
There is growing concern about the persistence, bioaccumulation, and toxicity of polybrominated diphenyl ether (PBDE) congeners. Kalantzi et al. (p. 1085) collected breast milk samples between late 2001 and early 2003 from resident mothers living in southeastern and northwestern England. Profiles of PBDE congeners, polychlorinated biphenyl congeners, and other selected chlorinated compounds indicated that the chemical constituents of the two groups were significantly different. The reasons for the differences are obscure, but identifying primary routes of contaminant exposures and their biologic effects is of great importance.
Land Use Change and Emergence of Infectious Disease
Anthropogenic land use changes drive a range of infectious disease outbreaks and emergence events, and modify the transmission of endemic infections. Patz et al. (p. 1092) report on the efforts of a working group to assess the current state of knowledge and to develop recommendations for addressing these environmental health challenges. The working group recommended creating research training centers to provide information to local communities, facilitate fully interdisciplinary research, and engage in communication and policy making.
Environmental Medicine
Cadmium Toxicity in a Nonoccupationally Exposed Population
Cadmium is a cumulative nephrotoxicant that is absorbed from dietary sources and cigarette smoking. Satarug and Moore (p. 1099) present evidence linking Cd-related kidney dysfunction and decreases in bone mineral density in nonoccupationally exposed populations who showed no signs of nutritional deficiency. Cd-linked bone and kidney toxicities were observed in people whose dietary Cd intakes were within the provisional tolerable weekly intake set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives.
Nutrition and Arsenic-Induced Skin Lesions
There is speculation that nutritional deficiencies increase adverse arsenic health effects. Mitra et al. (p. 1104) investigated whether dietary micro- and macronutrient intake modulates the well-established human risk of arsenic-induced skin lesions in West Bengal, India. Results indicate that low intake of calcium, animal protein, folate, and fiber may increase susceptibility to arsenic-induced skin lesions. However, in light of the small magnitude of increased risks related to these dietary deficiencies, prevention should focus on reducing exposure to arsenic.
Children's Health
Blood Lead Trend in Children in Mexico City
Schnaas et al. (p. 1110) evaluated the temporal trend in blood lead levels (BLL) among a cohort of children born in Mexico City between 1987 and 1992. BLL was measured every 6 months during a 10-year period. The mean air lead in the Mexico Valley decreased from 2.80 µg/m3 in 1987 to 0.07 µg/m3 in 2002. The contribution of air lead to blood lead according to year of birth was strongest for subjects born in 1987 and fell to nearly zero for children born in 1992. (Also see Science Selections, p. A569)
Prenatal OP Pesticide Exposure and Fetal Growth
Pesticide use is widespread, but little is known about adverse health effects of in utero exposure. Eskenazi et al. (p. 1116) investigated the relationship of organophosphate (OP) pesticide exposure during pregnancy with fetal growth and gestational duration in a cohort of low-income Latina women. There was no adverse relationship between fetal growth and any measure of in utero OP exposure. However, shortened gestational duration was clearly related to increasing exposure levels in the latter part of pregnancy.
Prenatal Insecticide Exposures and Birth Weight and Length
Whyatt et al. (p. 1125) expanded a previous analysis of the association of chlorpyrifos in umbilical cord plasma with birth weight and length to include diazinon and the carbamate propoxur. Cord plasma chlorpyrifos inversely correlated with birth length. Combined measures of (ln)cord plasma chlorpyrifos and diazinon (adjusted for relative potency) were also inversely associated with birth weight and length. Results indicate that prenatal chlorpyrifos exposures have impaired fetal growth among a minority cohort and that diazinon exposures may have contributed to the effects.
Biomarkers Indicate Susceptibility of the Fetus
Polycyclic aromatic hydrocarbons (PAHs) are released by many combustion sources. Perera et al. (p. 1133) compared fetal and adult susceptibility to PAHs and environmental tobacco smoke (ETS) using carcinogen-DNA adducts (a biomarker associated with increased cancer risk) and cotinine (a biomarker of tobacco smoke exposure) in paired blood samples collected from mothers and newborns. Results indicate increased susceptibility of the fetus to DNA damage and reduced ability to clear ETS constituents. The findings support the need to protect children as a sensitive subset of the population.
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Last Updated: June 16, 2004
