The Global Fool

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Prenatal Exposure to Air Pollutants: Links to Attention Deficit Hyperactivity Disorder
Apr11

Prenatal Exposure to Air Pollutants: Links to Attention Deficit Hyperactivity Disorder

By Roberta Attanasio PHAs — short for polycyclic aromatic hydrocarbons — are bad actors: they’re toxic, ubiquitous pollutants that readily cross the placenta, causing damage to the fetal brain. Now, results from a new study show that PHA-induced fetal brain damage may lead to severe behavioral problems during early childhood, including aggression and attention deficit hyperactivity disorder (ADHD). The deleterious effects of air pollution — greater risk of stroke, heart attacks and cognitive deterioration — are widely recognized. However, the new study assessed prenatal exposure and identified specific physical damage in the brain. The researchers used magnetic resonance imaging to measure the brains of 40 children from a cohort consisting of more than 600 mother-baby pairs. The mothers were either Latina (Dominican) or African American nonsmoking women from minority communities in New York City, aged 18 to 35 years. During the third trimester of pregnancy, the women carried personal backpack monitors that measured exposure to eight common PAHs over 48 hours. Such exposure occurred by breathing contaminated air. PHAs — common components of air pollution — are often found together in groups of two or more and persist in the environment for long periods of time. They’re generated by motor vehicles, waste incineration, wildfires and agricultural burning, and oil and coal burning for heat and electricity. Cooking (especially charred foods), tobacco smoke, and space heaters are indoor sources of PHAs. Low-income, urban, and minority communities are disproportionately exposed to these air pollutants. The researchers had previously demonstrated that exposure of the pregnant women from the same cohort to airborne PAHs was associated with multiple neuro-developmental disturbances. Results form the new study indicate that such disturbances have a biological root in the altered architecture of the brain. Specifically, PHA exposure was linked to reductions of the white matter surface in later childhood. These reductions were confined almost exclusively to the left hemisphere of the brain, and involved almost its entire surface. The researchers don’t know why the left side seemed to be affected more, but they suspect the compounds interfere with an early biochemical process that helps the fetal brain divide into slightly asymmetrical hemispheres. Results from the study also show that postnatal PAH exposure correlates with white matter surface measures in other regions of the brain, the dorsal prefrontal regions. Thus, the children involved in the study were exposed to “a double hit”, first as developing fetuses, and then at an early age. Indeed, Bradley Peterson, lead author of the study, told the Los Angeles Times: “It’s a double hit. They have the abnormality from prenatal life throughout the left hemisphere and then on top of that they have...

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Arsenic in Drinking Water: Increased Risk of Respiratory Infections and Lung Damage Following Fetal Exposure
Sep29

Arsenic in Drinking Water: Increased Risk of Respiratory Infections and Lung Damage Following Fetal Exposure

By Roberta Attanasio Odorless and tasteless, arsenic lurks everywhere – in rice and in chicken breasts, in apple juice and in drinking water. It’s all around, but not in amounts sufficient to cause acute (short-term) poisoning. On the other hand, chronic (long-term) exposure to lower arsenic doses occurs way too often, and may lead to cardiovascular disease, diabetes, cancers and other human disorders. Contamination of drinking water by arsenic is a global health threat. Presence of arsenic in groundwater is largely the result of minerals dissolving from weathered rocks and soils. In addition, arsenic enters the drinking water supply because of runoff from orchards, electronics production waste or other industrial activities. Bangladesh is considered a hot-spot for groundwater contamination with arsenic – however, the water supply is contaminated in many regions all around the world. Results from a study recently published in the journal Science (August 2013) indicate that in China 19.6 million people are at risk of being affected by the consumption of arsenic-contaminated groundwater.   Widespread high concentrations of arsenic are present in the groundwater of several areas of the U.S., including the West, the Midwest, parts of Texas, and the Northeast. The U.S. Geological Survey (USGS) develops maps that show where and to what extent arsenic occurs in groundwater across the country – The current maps are based on samples from 31,350 wells. Chronic exposure to arsenic through drinking water is linked to respiratory diseases. Arsenic affects the function of the immune system as well as lung development and causes increased susceptibility to respiratory infections. Results from a study carried out in Bangladesh and published in August in the journal American Journal of Respiratory and Critical Care Medicine show that arsenic induces lung damage similar to the damage induced by decades of tobacco smoking. The results also show that, especially in males, tobacco smoking makes arsenic-related damage even worse. “Restrictive lung defects, such as we saw in those exposed to well-water arsenic, are usually progressive and irreversible,” said Habibul Ahsan, Director of the Center for Cancer Epidemiology and Prevention at the University of Chicago Medicine and lead author of the study. “They can lead over time to serious lung disease.” As for many other pollutants, a major concern is prenatal exposure, which may lead to adverse health effects later on in life. Results from studies carried out in animal models suggest that arsenic exposure during adult and fetal life is linked to development of respiratory infections. In 2009, Courtney Kozul and collaborators published a study in the journal Environmental Health Perspectives showing that, in adult mice, arsenic exposure through drinking water significantly compromises the immune response to infection...

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