The Global Fool

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Global Threats: Contamination of Surface Waters by Agricultural Insecticides
Apr26

Global Threats: Contamination of Surface Waters by Agricultural Insecticides

By Roberta Attanasio The use of agricultural insecticides — toxic substances developed to target and kill insects that damage crops — has sparked controversy since the dawn of the “chemical age”, which started in the 1950s. The benefits of agricultural insecticides — for example, increased food production — are undeniable. Unfortunately, along with benefits, there are considerable unwanted effects. Ideally, insecticides must be lethal to the target insects, but not to non-target species. However, these toxic substances do not target only insects — they target many more organisms, including man. Thus, the toxic brew of agricultural insecticides threatens the ecological integrity of aquatic and terrestrial ecosystems. Indeed, agricultural systems play a significant role in global environmental degradation — among other harmful effects, they drive the loss of aquatic biodiversity. In 2013, a team of researchers from German and Australian institutions showed that the loss of aquatic biodiversity in regions of Germany, France, and Australia, is primarily due to the disappearance of several groups of species — stoneflies, mayflies, caddisflies, and dragonflies — which are especially susceptible to insecticides. These insects are important members of the food chain right up to fish and birds. Despite these worrisome results, the degree of insecticide contamination worldwide was unknown until two weeks ago, when results from a new study (Agricultural insecticides threaten surface waters at the global scale) showed that surface water pollution resulting from the current use of agricultural insecticides constitutes an excessive threat to aquatic biodiversity. For the new study, researchers at the Institute for Environmental Science of the University of Koblenz-Landau evaluated, for the first time, comprehensive global insecticide contamination data for agricultural surface waters. They examined 838 studies conducted between 1962 and 2012 and covering 2,500 aquatic sites in 73 countries, using the legally-accepted regulatory threshold levels (RTLs) as defined during the official pesticide authorization procedures. The researchers found that insecticide contamination occurs rarely in the aquatic environment — only an estimated 2.6% of the samples contained measurable levels of insecticides. However, for the sites containing insecticides, the results were alarming — more than 40% of the water-phase samples, and more than 80% of sediment samples in which insecticides were detected, yielded concentrations that exceeded the respective RTLs. They concluded that insecticides pose substantial threats to the biodiversity of global agricultural surface waters and that the current regulatory risk assessment schemes and pesticide authorization procedures fail to protect the aquatic environment. Ralf Schulz, one of the researchers, said in a press release: “Potential reasons for these findings are failures of current risk assessment procedures, or the non-adherence of farmers to pesticide application prescriptions.” It is likely that the global picture emerging from the...

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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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Food Additives, Microbiota, and Inflammation
Mar27

Food Additives, Microbiota, and Inflammation

By Roberta Attanasio “For centuries, additives have served useful functions in a variety of foods. Our ancestors used salt to preserve meats and fish, added herbs and spices to improve the flavor of foods, preserved fruit with sugar, and pickled cucumbers in a vinegar solution. Today, consumers demand and enjoy a food supply that is flavorful, nutritious, safe, convenient, colorful and affordable. Food additives and advances in technology help make that possible.” But, are food additives safe? Results from a recent study show that some food additives known as emulsifiers can alter the composition and location of the gut microbiota — the diverse population of 100 trillion bacteria that inhabit the intestinal tract — thus inducing intestinal inflammation. This inflammation, in turn, promotes the development of inflammatory bowel disease (Crohn’s disease and ulcerative colitis) and metabolic syndrome — disorders that are often severe and debilitating and afflict millions of people. The ancient Greeks used the emulsifying power of beeswax in cosmetic products. Egg yolk was probably the first emulsifier ever used in food production back in the early 19th century. Emulsifiers are now added to bread, chocolate, ice cream, margarine, processed meat, and more. But why? Add oil to water and the two liquids will never mix. At least not until an emulsifier is added. Emulsifiers are molecules with one water-loving (hydrophilic) and one oil-loving (hydrophobic) end. They make it possible for water and oil to become finely dispersed in each other, creating a stable, homogenous, smooth emulsion. The study results show that, in a mouse model, two common emulsifiers — caboxymethylcellulose (CMC) and polysorbate-80 (P80) — not only change the composition of the gut microbiota, they also make the gut more porous. The altered microbiota has enhanced capacity to digest and infiltrate the dense mucus layer that lines the intestine — bacteria reach immune cells, thus inducing activation of inflammatory pathways and the development of severe inflammation. Such changes in bacteria trigger chronic colitis in mice genetically prone to this disorder, due to abnormal immune systems. In contrast, in mice with normal immune systems, emulsifiers induce low-grade or mild intestinal inflammation and metabolic syndrome, characterized by increased levels of food consumption, obesity, hyperglycemia and insulin resistance. Fergus Shanahan (University College Cork), who was not involved in the study, told Ed Yong: “This work cannot be ignored.” He doubted that most people would be significantly affected by occasionally eating foods with emulsifiers — but risk might change for those who have a genetic predisposition to inflammatory bowel disease, or who eat lots of processed foods. Andrew Gewirtz, senior author of the study, said in a press release: “We do...

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Early Menopause: Links to Ubiquitous Endocrine-Disrupting Chemicals
Feb23

Early Menopause: Links to Ubiquitous Endocrine-Disrupting Chemicals

By Roberta Attanasio There are as many endocrine-disrupting chemicals (also called endocrine disruptors) as there are deleterious health effects caused by them. These chemicals mimic the body’s hormones and confuse our physiological systems — we respond to them with a series of inappropriate changes that, depending on the specific endocrine disruptor, lead to the development of obesity, cancer, malformation of sex organs, and more. They are pervasive in the environment — they’re found in the soil, air and water throughout the world — and many persist for long periods of time. Thus, it’s not surprising that, in 2013, the impact of endocrine disruptors on human health was defined as a “global threat” by a group of experts convened by the United Nations Environment Programme and the World Health Organization.   Phthalates are some of the most studied endocrine disruptors. They’re used to make plastic more flexible and cosmetics smoother. Phthalate use in children’s toys was banned in 2008. However, results from a recent study show that high amounts of certain phthalates are present in some meats, cooking oils and dairy products, thus contributing to children exposure despite the ban. In her article “A threat to male fertility“, Deborah Blum writes: “A growing body of work over the last two decades suggests that phthalates can rewire the male reproductive system, interfering with the operation of androgenic hormones, such as testosterone, that play key roles in male development. That mechanism, some experts believe, explains findings that link phthalate exposure to changes in everything from testicular development to sperm quality.” In addition, according to results from a new study, two phthalates belong to a group of 15 chemicals that are significantly associated with early menopause and may have detrimental effects on ovarian function. Earlier menopause and decline in ovarian function may adversely affect fertility and lead to earlier development of heart disease and osteoporosis. The other chemicals are nine polychlorinated biphenyls, three pesticides, and a furan. Women that have high levels of these chemicals in their bodies experience menopause two to four years earlier than women with lower levels of these chemicals. For the study, the researchers analyzed data collected from 1999-2008 as part of the National Health and Nutrition Examination Survey, conducted by the U.S. Centers for Disease Control and Prevention. The survey incrporated data from 31,575 people, including 1,442 menopausal women who had been tested for presence of endocrine-disrupting chemicals in their blood and urines. It was designed so that the women who had undergone chemical testing would represent a population of almost 9 million menopausal women. The strongest association with early menopause was found for mono-(2-ethyl-5-hydroxyhexyl) phthalate and mono-(2-ethyl-5-oxohexyl) phthalate,...

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E-Cigarettes and Vaping May Cause Lung Damage and Impaired Immune Responses
Feb14

E-Cigarettes and Vaping May Cause Lung Damage and Impaired Immune Responses

By Roberta Attanasio A few months ago, Oxford Dictionaries announced “vape” as its international Word of the Year 2014 – language research conducted by their editors revealed that its use in 2014 had more than doubled compared to 2013 (and increased by 30-fold since 2012), mostly because of the rapidly growing popularity of electronic cigarettes and the expanding debate over their safety. Although e-cigarettes are portrayed as devices that can help adult smokers quit while providing a safe alternative to tobacco smoking, mounting evidence shows that these devices may cause considerable harm. Indeed, about two weeks ago, California health officials said that e-cigarettes represent a rising public-health risk that threaten to unravel progress made on tobacco by “re-normalizing smoking behavior” and luring a new generation into nicotine addiction. Electronic cigarettes, or e-cigarettes, are tobacco-free and vaporize liquid (also called e-liquid or e-juice) that contains nicotine, producing “faux” smoke or vapor. Because they don’t burn anything, e-cigarettes don’t release any smoke – therefore, users don’t “smoke”, they “vape.” In addition to nicotine, the e-juice typically contains vegetable glycerin, propylene glycol, and flavorings. There are several types of e-juices, each containing different flavorings – these flavorings make “vaping” especially appealing to young smokers who would not normally try tobacco. While nicotine addiction caused by vaping in young smokers is clearly a major public health issue, there are also public health concerns associated with toxic substances released by e-cigarette vapors. Indeed, e-cigarettes may likely become a toxic replacement for tobacco products. Results from a recent study (published in the scientific journal PLOSone) show that emissions from e-cigarettes damage lung cells. The damage is mostly caused by inflammatory responses and oxidative stress, which are known to represent key events in the development of chronic airway diseases. Some flavored e-juices – particularly those containing cinnamon – are more toxic than others. Irfan Rahman, lead author of the study, said in a press release: “Several leading medical groups, organizations, and scientists are concerned about the lack of restrictions and regulations for e-cigarettes. Our research affirms that e-cigarettes may pose significant health risks and should be investigated further. It seems that every day a new e-cigarette product is launched without knowing the harmful health effects of these products.” Results from an additional study recently published in the same journal confirm that vaping may cause potential deleterious health effects. Using a mouse model, the researchers showed that e-cigarettes compromise the immune system in the lungs and generate some of the same potentially dangerous chemicals found in traditional nicotine cigarettes. Thomas Sussan, lead author of this study, said in a press release: “E-cigarette vapor alone produced mild effects...

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