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Arsenic Contamination of Drinking Water in India Impairs Kala-Azar Treatment
Oct30

Arsenic Contamination of Drinking Water in India Impairs Kala-Azar Treatment

By Roberta Attanasio Visceral leishmaniasis, known in India as kala-azar or black fever, is a parasitic disease that kills an estimated 500,000 people a year, 90 percent of them in India, Nepal, Bangladesh, Brazil and Sudan. In India, the disease is endemic in the northeastern Indian State of Bihar – the epicenter of kala-azar in the region – and in Jharkhand, Uttar Pradesh and West Bengal. It manifests with irregular bouts of fever, substantial weight loss, swelling of the spleen and liver, and anemia. Left untreated, kala-azar is almost always fatal, especially in children, According to the World Health Organization (WHO), “Leishmaniasis is a poverty-related disease. It affects the poorest of the poor and is associated with malnutrition, displacement, poor housing, illiteracy, gender discrimination, weakness of the immune system and lack of resources. Leishmaniasis is also linked to environmental changes such as deforestation, building of dams, new irrigation schemes and urbanization, and the accompanying migration of non-immune people to endemic areas.” Leishmania, the protozoan parasite that causes kala-azar, spreads to humans through the bite of infected female sandflies. No vaccine has yet been licensed to prevent infection. Drugs to treat the disease are toxic and expensive. In Bihar, where 90% of India’s large kala-hazar burden is located, the parasite has developed resistance to one of the main treatments, a group of drugs known as antimonial preparations. Indeed, the effectiveness of the antimonial preparations is now so low that these drugs are no longer recommended in the Indian subcontinent, whereas they remain an essential part of the treatment for visceral leishmaniasis in South America and sub-Saharan Africa. Now, researchers at the Universities of Dundee and Aberdeen in the U.K. report, in an article published in the journal Proceedings of the National Academy of Sciences of the United States of America, that arsenic contamination of the water supply may have played a significant role in building the resistance of leishmania to the antimonial drugs. In the article, the researchers state: “The Indian subcontinent is the only region where arsenic contamination of drinking water coexists with widespread resistance to antimonial drugs that are used to treat the parasitic disease visceral leishmaniasis.” The article (October 28, 2013) is entitled “Chronic exposure to arsenic in drinking water can lead to resistance to antimonial drugs in a mouse model of visceral leishmaniasis” Professor Alan Fairlamb, senior author of the article, said: ”The water supply in Bihar has been found to be affected by contamination from naturally occurring arsenic in the groundwater. What we have been able to show through experiments is that arsenic contamination of water can build resistance in Leishmania parasites to antimonial treatments.” The researchers performed their experiments...

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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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Arsenic in Rice: Links to Genetic Damage
Jul27

Arsenic in Rice: Links to Genetic Damage

By The Editors Rice is a staple food for over 3 billion people worldwide. Unfortunately, rice contaminated with arsenic can be found in several regions of our planet. Although serious concerns have been raised in the past few years over the consumption of rice tainted with high levels of arsenic, there was no direct proof of its harmful effects on human populations. Now, results from a new study indicate that staple consumption of cooked rice containing high levels of arsenic leads to genotoxic damage. Arsenic, one of the heavy metals, is a chemical element normally present in water, air and soil. It is released from volcanoes and from the erosion of mineral deposits as well as from human activities (mining, burning coal, oil, gasoline and wood). Presence of arsenic in the environment is also due to its use in compounds such as pesticides, herbicides and wood preservatives.  The arsenic content in rice varies widely depending on the rice provenience: rice grown in arsenic-contaminated soil and groundwater contains higher arsenic than average. The new study, entitled “High arsenic in rice is associated with elevated genotoxic effects in humans” and published on July 22, 2013, in the scientific journal Scientific Reports, was designed to determine whether or not cooked rice with high arsenic content is sufficient to cause genotoxic effects in humans in absence of any additional exposure. The study populations consisted of individuals living in rural West Bengal, India, eating rice as a staple. To determine arsenic toxicity and genetic damage the investigators determined the frequency of micronuclei – a tell-tale sign of chromosomal damage – in cells extracted from urine samples. Increased frequency of micronuclei is known to be linked to the development of cancers. The investigators demonstrated that people eating rice containing arsenic in amounts greater than 0.2 mg/kg had higher frequencies of micronuclei than people consuming rice containing less arsenic.  The trend of greater genetic damage with increasing arsenic in rice was observed for both men and women, for tobacco-users and non-users, and for those from three different locations within the study area. The pattern observed was broadly similar to that previously seen for people exposed to arsenic through drinking high arsenic well waters, which has caused devastating health impacts, including cancers, in many parts of the world. Rice is not the only type of food that may lead to high levels of arsenic exposure. Another example is that of cooked chicken breasts. As you may remember from one of our previous posts, “Arsenic in Chickens: Finding More of What is Already Known“, a recent study found that several samples of U.S. chicken breasts contained potentially harmful...

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Arsenic in Chickens: Finding More of What Is Already Known
Jul07

Arsenic in Chickens: Finding More of What Is Already Known

By The Editors Despite the high toxicity of arsenic, there are arsenical drugs — in other words, there are drugs that contain arsenic.  One of these drugs, roxarsone, is used in chicken feeds to kill intestinal parasites, promote growth (make the chicken grow faster) and improve pigmentation (make meat look pinker). Roxarsone contains organic arsenic, which is much less toxic than inorganic arsenic. However, mounting evidence suggests organic arsenic can change into inorganic arsenic once administered to chickens. The U.S. Environmental Protection Agency (EPA) classifies inorganic arsenic as a known human carcinogen — This classification is based on extensive population studies of lung cancers that developed following arsenic exposure through inhalation, and skin cancers that developed following ingestion of contaminated drinking water in adults.  According to the EPA, arsenic exposure also may be associated with a higher incidence of bladder, liver, kidney, and prostate cancer. The World Health Organization International Agency for Research on Cancer (IARC) classifies arsenic as a known (Group 1) human carcinogen. In 2011, the leading U.S. roxarsone marketer Pfizer suspended U.S. roxarsone sales after tests carried out by the Food and Drug Administration (FDA) found traces of inorganic arsenic in chicken livers. The FDA study did not provide data on the presence of inorganic arsenic in chicken meat. Now, results from a study published in May in the scientific journal Environmental Health Perspectives (EHP) show that inorganic arsenic may accumulate in the meat of treated chickens. The EHP study (Nachman KE, et al. Roxarsone, inorganic arsenic, and other arsenic species in chicken: a U.S.-based market basket sample. Environ Health Perspect 121(7):818–824, 2013, http://ehp.niehs.nih.gov/1206245/), which analyzed chicken breast samples from 10 geographically diverse metropolitan areas across the United States, is the first to show presence of inorganic arsenic in retail chicken meat. The study samples were collected from December 2010 through June 2011, and therefore prior to the suspension of roxarsone marketing. Marketing, however, has continued in other countries and Pfizer still domestically markets the arsenical drug nitarsone, which is chemically similar to roxarsone. Currently, in the U.S. there is no federal law prohibiting the sale or use of arsenic-based drugs in chicken feed. Lead author Keeve Nachman (Johns Hopkins Center for a Livable Future) said, “The suspension of roxarsone sales is a good thing in the short term, but it isn’t a real solution. Hopefully this study will persuade FDA to ban the drug and permanently keep it off the market.” There is something more to take into account — Results from the EHP study show that cooking chicken breasts decreased the levels of roxarsone. However, cooking chicken breasts increased the concentration of inorganic arsenic in the...

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