Environews
Wisconsin Center Focuses on Zebrafish
The zebrafish has a number of advantages to offer as a model of developmental toxicology. This month's NIEHS News (p. A160) describes how researchers at the institute-sponsored Marine and Freshwater Biomedical Sciences Center at the University of Wisconsin-Milwaukee are working to make the zebrafish and other aquatic species the next classic animal models.
Great Lakes, Great Problems
The Focus (p. A164) examines the current state of the Great Lakes. These water bodies, which contain about 84% of the U.S. surface freshwater supply, have suffered over the years from severe pollution and invasion by exotic species. Progress has been made in alleviating the worst of the pollution, but the lakes are still plagued by persistent contaminants. Will it ever be possible to return this natural resource to a nonthreatened state?
Policy Pileup
The Great Lakes are as rich in policy as they are in history--the United States alone has about 140 programs dedicated to the care and maintenance of this resource. So why are the lakes still at risk? The Spheres of Influence (p. A174) takes a look at the history of Great Lakes legislation and points where policies overlap, diverge, and just plain miss the mark.
A Turning Point for Tomatoes?
At a time when new health benefits of tomato extract are being discovered all the time, Florida's tomato farmers are faced each year with seeing much of their crop rot on the vine as the market sags under a surplus of produce. The Innovations (p. A178) describes a method developed at the University of Florida that may provide a cheap, effective way to turn those extra tomatoes into tomato extract--a boon for farmers and health buffs alike.
Research
Environmental Public Health Tracking
The Centers for Disease Control and Prevention recently announced a national Environmental Public Health Tracking (EPHT) network with the goal of linking environmental and chronic disease data. Ritz et al. (p. 243) suggest how such a system should be developed, but they caution that formal linkage of data is not the only approach required for an effective EPHT program. The primary goal must be treatment of the environment to prevent and/or reduce exposures and minimize risk for chronic diseases.
Trivalent Methylarsenic Metabolites in Human Urine
Valenzuela et al. (p. 250) examine the relationship between urinary profiles of methylarsonite (MAsIII) and dimethylarsinite (DMAsIII) and skin lesion markers of inorganic arsenic (iAs) toxicity in individuals exposed to iAs in drinking water. The goal was to investigate the urinary profiles for the trivalent and pentavalent As metabolites in both high- and low-iAs-exposed subjects. The data suggest that urinary levels of MAsIII may serve as an indicator to identify individuals with increased susceptibility to toxic and cancer-promoting effects of arseniasis.
Crystalline Silica Exposure
Yassin et al. (p. 255) summarized respirable crystalline silica dust exposure levels among U.S. workers using inspection data from the Occupational Safety and Health Administration (OSHA) Integrated Management Information System for 1988-2003. The mean of silica exposure for an 8-hr personal time-weighted average among samples was 0.077 mg/m3, well above the American Conference of Governmental Industrial Hygienists threshold limit value of 0.05 mg/m3. Although a downward trend in the exposure levels was observed, the results showed that 3.6% of workers were exposed above the OSHA permissible limit of silica.
Trends in Intersexuality in Cricket Frogs
Reeder et al. (p. 261) examined gonads of cricket frogs (Acris crepitans) collected in Illinois and deposited in museum collections to elucidate relationships between species decline and the spatial/temporal distribution of individuals with intersex gonads. Compared with the preorganochlorine (OC) era (1852-1929), the percentage of intersex cricket frogs increased during the industrial growth and initial uses of polychlorinated biphenyls (PCBs) from 1930 to 1945, peaked during the greatest manufacture and use of p,p-dichlorodiphenyltrichloroethane (DDT) and PCBs from 1946 to 1959, began declining with environmental regulations that reduced sales of DDT from 1960 to 1979, and continued to decline through reductions in OCs and PCBs from 1980 to 2001. (Also see Science Selections, p. A182)
Mercury in Commercial Fish
Attention to the risk from fish consumption has focused on self-caught fish, although most people eat commercially purchased fish. Burger et al. (p. 266) examined mercury levels in tuna, flounder, and bluefish available in New Jersey stores to determine whether mercury levels differed by region of the state, economic neighborhood, or type of store. There were species differences, with tuna having the highest levels and flounder the lowest levels. There were no significant differences by type of store or economic neighborhood. Flounder from along the Jersey shore had higher mercury levels than flounder bought in other markets. (Also see Science Selections, p. A183)
PCB Exposure and CYP1A2 Activity
Cytochrome P450 1A2 (CYP1A2) is an enzyme involved in the metabolic activation of some carcinogens. Fitzgerald et al. (p. 272) studied CYP1A2 activity among Native Americans exposed to polychlorinated biphenyls (PCBs) from consumption of St. Lawrence River fish. The authors analyzed serum PCBs and used the caffeine breath test (CBT) as a probe for CYP1A2 activity. The results indicate that CYP1A2 activity may be marker of an early biological effect of exposure to PCBs in humans and that the CBT may be useful to monitor the effects.
Estrogens Captured by ER-
In order to characterize compounds that mediate estrogenic activity in river water and sediment samples, Pillon et al. (p. 278) designed an assay in which high-affinity estrogenic compounds are captured by recombinant estrogen receptor (ER)- leading to a selective inhibition of transactivation. The approach identifies water samples containing high-affinity compounds at low concentrations and can be used to separate ligands present in river sediments for ER and the aryl hydrocarbon receptor.
Carbofuran Exposure and Cancer Incidence
Carbofuran is a carbamate insecticide used on a variety of food crops. Bonner et al. (p. 285) examined carbofuran exposure and tumor sites among licensed pesticide applicators from Iowa and North Carolina enrolled in the Agricultural Health Study. Lung cancer risk was 3-fold higher for those with > 109 days of lifetime exposure to carbofuran compared with those with < 9 lifetime exposure days, with a significant dose-response trend for both days of use per year and total years of use. Carbofuran use was not associated with lung cancer risk when the nonexposed subjects were used as the referent. Carbofuran exposure was not associated with any other cancer site.
Air Pollution and Respiratory Admissions
Luginaah et al. (p. 290) examined the association between air pollution and daily respiratory hospitalization for different age and sex groups from 1995 to 2000 in Windsor, Ontario, Canada. Results indicate associations between NO2, SO2, CO, coefficient of haze, and particulate matter ≤ 10 µm (PM10) and daily hospital admission for respiratory diseases, especially among females. There were no significant associations between ozone and total reduced sulfur with respiratory admissions.
Measurement of Chemicals in Umbilical Cord
Umbilical cord (UC), umbilical cord serum (CS), and maternal serum (MS) are all used to assess fetal exposure to chemicals. Fukata et al. (p. 297) measured the association between persistent chemicals in the three maternal and fetal tissues to determine which type is the best for fetal exposure assessment. On the basis of correlation coefficients, they conclude that UC is the best sample to assess fetal contamination status of persistent chemicals. They suggest that assessment based on contaminant levels in CS may result in an underestimation.
Air Pollution and Heart Rate Variability
Reduced heart rate variability (HRV), a marker of poor cardiac autonomic function, is associated with air pollution. Park et al. (p. 304) examined the relationship between HRV [standard deviation of normal-to-normal intervals (SDNN), power in high frequency (HF) and low frequency (LF), and LF/HF ratio] and ambient air pollutants among men in Boston, Massachusetts, between November 2000 and October 2003. The associations between HRV, fine particulate matter (PM2.5), and ozone were stronger in people with ischemic heart disease (IHD) and hypertension. The associations between SDNN and LF and PM2.5 were stronger in people with diabetes. Hypertension, IHD, and diabetes may confer susceptibility to autonomic dysfunction by air pollution.
Syntrophic Associations in Degradative Communities
Stable association of syntrophic fermentative organisms and populations is essential for mineralization of chlorinated aromatic compounds under methanogenic conditions. Becker et al. (p. 310) used two complementary nucleic acid-based methods to track changes in the abundance of populations in anaerobic microbial communities that mineralized chlorinated aromatic compounds. Results indicate that methanogens benefit from the influx of benzoate-derived electron donors and that the activities of Syntrophus-like and methanogenic populations in the contaminant-degrading communities are closely linked.
Bioremediation of MTBE-Contaminated Groundwater
The fuel additive, methyl tertiary butyl ether (MTBE) has become a widespread groundwater contaminant. Laboratory studies revealed that bacterial strain PM1 biodegrades MTBE in groundwater sediments. Smith et al. (p. 317) tested bacterial strain PM1 in an in situ field study at Port Hueneme Naval Construction Battalion Center, Oxnard, California. MTBE declined over time down-gradient from both PM1 treated and untreated groundwater. Addition of oxygen to naturally occurring microbial populations was sufficient to stimulate MTBE removal.
Chlorinated Pesticides and Autoimmunity in Mice
Systemic lupus erythematosus (SLE) is an autoimmune disorder that affects women more frequently than men. In the (NZB 
NZW)F1 mouse, a murine SLE model, the presence or absence of estrogen influences the rate of SLE progression. Sobel et al. (p. 323) administered three chlorinated pesticides chronically to ovariectomized female (NZB NZW)F1 mice and measured the time to development of renal disease. Although they hypothesized that the effect on progression was due to pesticide estrogenic properties, autoimmune effects and estrogenicity, assessed by uterine hypertrophy, were not well correlated. (Also see Science Selections, p. A182)
A Gene Reporter for Estrogenic Activity in the Brain
Trudeau et al. (p. 329) used in vivo somatic gene transfer to introduce an estrogen response element (ERE)-luciferase construct into the brain of amphibian tadpoles (Xenopus laevis) and goldfish (Carassius auratus). Activation of an ERE-dependent luciferase reporter gene in both tadpoles and fish indicates that waterborne estrogens can directly modulate transcription of estrogen-responsive genes in the brain. This method may be adaptable to other aquatic organisms in order to study the direct regulation of estrogen responsive genes in vivo.
Development of Health Models for the Future
Ebi and Gamble (p. 335) report on the efforts of a workshop designed to review current strategies for developing human health models and scenarios in the context of global environmental change. The research agenda focused on the development and use of health models and health scenarios to guide policy and identified research gaps and barriers to the development and use of models and scenarios.
Environmental Medicine
Intervention for Arsenic Poisoning
Chronic arsenic exposure causes vascular diseases associated with systematic dysfunction of endogenous nitric oxide. Replacement of arsenic-contaminated drinking water with low-arsenic water is a potential intervention strategy. Pi et al. (p. 339) examined a urinary marker of the vaso-active effects of NO and peripheral vascular function in arsenosis patients before and after water replacement. The intervention study indicates that peripheral vascular disease in arsenosis patients can be reversed by exposure cessation and has implications in the public health approach to arsenic exposure.
Children's Health
Blood VOC Levels in Children
Sexton et al. (p. 342) measured blood concentrations of 11 volatile organic compounds (VOCs) over 2 years in a probability sample of children from two poor, minority neighborhoods in Minneapolis, Minnesota. Blood levels of styrene were more than twice as high, and for about 10% of the children 1,4-dichlorobenzene levels were 10 times higher compared to NHANES III. Strong statistical associations were observed between numerous pairwise combinations of VOCs, but no significant associations were observed between total urinary cotinine and blood VOC concentrations. There were strong associations between measured blood VOC concentrations for siblings in the same household.
Asthma and Farm Exposures in a Cohort of Rural Iowa Children
Farm children are less often reported to be atopic and to have less allergic disease and asthma than nonfarm children. Merchant et al. (p. 350) studied a cohort of rural Iowa children to determine the association between farm and other environmental risk factors with four asthma outcomes. Doctor-diagnosed asthma prevalence was 12%, but at least one health outcome was found in over a third of the cohort. Multivariable models found independent associations between several variables, including a high prevalence of asthma health outcomes among children living on farms that raise swine (44.1%) and that raise swine using added feed antibiotics (55.8%).
Home Dampness and Molds
Jaakkola et al. (p. 357) conducted a population-based, longitudinal 6-year prospective cohort study of the joint effects of parental atopy and exposure to molds on the development of asthma among children 1-7 years of age at the baseline. The outcome of interest was development of asthma during the study period. In Poisson regression adjusting for confounding, parental atopy and the presence of mold odor in the home reported at baseline were independent determinants of asthma incidence, but no apparent interaction was observed.
Racial Differences in Serum and Hair Cotinine
African-American children suffer disproportionately from tobacco-related illnesses, and have higher levels of serum cotinine. Wilson et al. (p. 362) tested whether African-American children have higher levels of serum and hair cotinine, after accounting for environmental tobacco smoke (ETS) exposure and housing characteristics. After adjusting for ETS exposure, housing size, and other demographic characteristics, serum and hair cotinine levels remained significantly higher in African-American children compared with white children. Despite a lower exposure to ETS, African-American children with asthma had significantly higher levels of both serum and hair cotinine.
