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Researchers assessed the associations between airborne emissions from oil and gas field facilities and the structure and function of the immune system of yearling beef cattle in 27 herds during spring 2002. They evaluated the immune systems of these animals by enumerating B lymphocytes and T-lymphocyte subtypes (CD4, CD8, γδ, and WC1) in peripheral circulation and by measuring systemic antibody production in response to vaccination. Researchers prospectively measured exposure to sulfur dioxide, hydrogen sulfide, and volatile organic compounds (VOCs) by using air-quality data from passive monitors installed in pastures and wintering areas. They estimated the mean exposure of each animal over the 6-month period before the start of sample collection. The researchers used mixed models, which adjusted for clustering by herd and accounted for known risk factors, to examine potential associations between exposure to airborne sulfur dioxide, VOCs (measured as concentrations of benzene and toluene) and hydrogen sulfide, as well as proximity to emission sources (well-site density), and the immune system outcomes. Increasing exposure to VOCs measured as toluene was associated with significant CD4 T lymphocytopenia. The number of CD4 T lymphocytes was 30% lower in cattle exposed to VOCs measured as toluene in the highest quartile (> 0.823 μg/m3) than in cattle exposed in the lowest quartile (< 0.406 μg/m3). [ABSTRACT FROM AUTHOR]

To investigate the associations between emissions from oil and gas field facilities and fetal survival, researchers followed more than 28,000 beef cows from the beginning of the breeding season through calving. They prospectively measured exposure to sulfur dioxide, hydrogen sulfide, and volatile organic compounds and linked them to the location of individual cattle; they used the density of oil and gas well sites surrounding each pasture as an alternate measure of exposure. The researchers measured the risks of abortion and stillbirth in 203 cow-calf herds for the 2002 calving season, as well as animal and herd-management factors known or suspected to affect these parameters. Using mixed models to adjust for clustering by herd and after accounting for other known risk factors, they examined the associations between exposure to sulfur dioxide, volatile organic compounds measured as benzene and toluene, hydrogen sulfide, and well-site density, and the risks of abortion and stillbirth. There was no evidence across the measured range of exposures that emissions of sulfur dioxide, hydrogen sulfide, volatile organic compounds measured as benzene or toluene, or well-site density increased the risk of either abortion or stillbirth in these beef herds. [ABSTRACT FROM AUTHOR]

To determine potential associations between emissions from oil and gas field facilities and the risk of lesions in the immune, nervous, and respiratory systems of beef calves, researchers examined tissue samples collected from 1,531 cases with exposure data, which included aborted fetuses, stillbirths, and calf mortalities from 203 cow-calf herds, by means of histopathology. The researchers prospectively measured exposure to sulfur dioxide, hydrogen sulfide, and volatile organic compounds by using air-monitoring data from passive monitors. They used the density of facilities surrounding each pasture as a second measure of exposure. Each tissue was classified by the presence or absence of a series of specified lesions, including those associated with degeneration, necrosis, infection, inflammation, anomaly, lympholysis (for lymphoid tissue), and proliferation (for the respiratory system). Exposure was not associated with the risk of lesions to tissues of either the immune or nervous system in calves that were aborted or died in spring 2002. Exposures to sulfur dioxide and hydrogen sulfide were not significantly associated with the risk of lesions to respiratory tissues in calves that were born alive in spring 2002. Increasing postnatal exposures to volatile organic compounds measured as benzene and toluene were associated with increased odds of respiratory lesions. The association between volatile organic compounds measured as benzene and respiratory lesions was significant for calves older than 3 weeks. During gestation, increasing exposure to sulfur dioxide was associated with increased odds of lesions in either the skeletal muscle or myocardium. [ABSTRACT FROM AUTHOR]

To determine if oil- and gas-facility emissions prospectively measured as airborne sulfur dioxide and volatile organic compounds (VOCs) were associated with immunomodulation in neonatal beef calves, veterinarians collected samples from 325 calves from 60 western Canadian herds in the spring of 2002. Researchers assessed immune system effects by enumerating B-lymphocytes and specific T-lymphocyte subtypes (CD4, CD8, γδ, and WC1) in peripheral circulation using flow cytometry. They estimated in utero exposure for each calf from the earliest possible breeding date of the dam to the calving date, using air-quality data from passive monitors installed in pastures and wintering areas. Numbers of circulating CD4 and CD8 T-lymphocytes were 42% and 43% lower, respectively, in calves exposed to the highest quartile (&nvge; 0.378 μg/m3) of VOCs measured as airborne concentrations of benzene compared with calves exposed to concentrations in the lowest quartile (< 0.276 μg/m3). Similarly, the number of CD4 T-lymphocytes was 40% lower in calves exposed to VOCs measured as concentrations of toluene in the highest quartile (&nvge; 0.713 μg/m3), compared with calves exposed to concentrations in the lowest quartile (< 0.348 μg/m3). There was no statistically significant association between in utero exposure and numbers of B-lymphocytes and γδ and WC1 T-lymphocyte subtypes in calf blood samples. [ABSTRACT FROM AUTHOR]

Concerns regarding adverse health effects of exposure to environmental pollutants among children are increasing. This subject area is particularly important in China because of environmental pollution problems associated with rapid development and a large population. The authors provide what is, to their knowledge, the first review in China of English- and Chinese-language literature regarding the current status of environmental exposures to children in China and the impact of these exposures on the health of children. Children in China are exposed to diverse environmental pollutants, including traditional pollutants such as lead and mercury and emerging pollutants such as phthalates and perfluorinated compounds. Incidence and prevalence of certain childhood diseases have increased in last decades. In China, a limited number of data on environmental exposure and children's health are available, and further high-quality studies are needed. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue such as the findings with regard to the Western Canada Study focusing on the effects of oil and natural gas emission exposures to animal health and questions regarding the emissions' effect on cattle reproduction and survival.