Arsenic is a semi-metallic element occurring naturally and abundantly throughout the earth. It commonly surfaces by natural processes and often has a negligible presence in water, but can also be exposed in devastating amounts both naturally and due to human industry, typically agricultural irrigation or mining. However exposed, arsenic poisoning in drinking water has led to a health crises in third world countries such as Bangladesh, but also threatens affluent nations like the United States. Many problems have arisen amidst the efforts to remedy other health concerns, such as the endeavour to transport water free of various diseases including diarrhoea, dysentery, typhoid, cholera and hepatitis. In trying to solve these hazards, arsenic has unexpectedly been exposed.
The pure form of arsenic is not usually found in the natural environment. It is more commonly found combined with oxygen, chlorine and/or sulphur and is referred to as inorganic arsenic. When arsenic is combined with carbon and hydrogen it is called organic arsenic and is much less toxic. Organic arsenic is commonly found in most seaweed and other marine food and has not been known to pose any health risk to humans. Commercially, arsenic is used heavily in alloying agents, in the manufacture of glass to clarify the colour tainted by impurities, to harden lead and also in the production of military poisonous gases. The inorganic arsenic responsible for the majority of the arsenic cancer cases releases into underground water sources through rocks and soil. Sometimes natural erosion can introduce large quantities of arsenic into a local water source. Arsenic is also released into the environment through the manufacturing of pesticides, the burning of fossil fuels, and cigarette smoke. It enters water sources through the dissolution of minerals and ores, from industrial effluents, and from atmospheric deposition. A poisonous amount for human beings is anything greater than 65 mg, whether taken in a single dose or built up from multiple amounts.
A few of the many symptoms linked to chronic exposure are hyperpigmentation, depigmentation, keratosis, and peripheral vascular diseases. Various internal cancers, skin cancer, cardiovascular and neurological diseases have also been linked to arsenic exposure and ingestion. The US National Academy of Sciences reported in 1999 that arsenic can cause bladder, lung and skin cancer, and might cause liver and kidney cancer. The harmful effects of arsenic poisoning are magnified by other health problems such as Hepatitis B or malnutrition. Generally skin lesions first appear after a period of roughly five years of exposure. Because the exact amount of arsenic intake is often unknown, scientists have difficulty predicting future effects. Much ambiguity remains in understanding the precise ramifications of arsenic intake on account of the complexity of factors: the status of the arsenic, the nutritional situation of the infected people, and the effect of other diseases make research slow and difficult. The most crucial remedial action promoted at present is prevention of further exposure and the provision of safe water—two obvious but complex solutions.
Arsenic poisoning affects an enormously diverse range of people. It reaches both the poor and rich, and even when the latter could afford to do something about it they often lack knowledge of the problem. One family in Michigan, a mother and her three children, lived for years in agony enduring extreme fatigue, hair loss, and skin gashes while 16 different doctors failed to diagnose their ailment. Finally, the seventeenth doctor determined their troubles came from arsenic poisoning in their water. Michigan has more naturally occurring arsenic than anywhere else in the United States. For a long time many counties ignored or denied the problem, but recently it has become an unavoidable issue. If a stricter standard for arsenic were enforced, 450 out of 3000 wells that serve about 8000 people in Michigan would fail and each well would cost a million dollars to upgrade. The fact that arsenic levels in wells can fluctuate within hours, changing from safe to toxic, makes the process frustrating and tedious.
In March 2001 the Bush Administration declared that it intended to slacken drinking water standards that were enforced to protect the public, specifically 13 million Americans who have elevated levels of arsenic in their drinking water. In January 2001 after ten years of research the Environmental Protection Agency concluded a new safety standard for arsenic in drinking water of 10 parts per billion. The old precedent from 1942 was 50 parts per billion, the standard that would be reverted to. The Bush Administration declared that its decision was founded on the lack of consensus on the new standard number, an assertion that has many sceptics questioning Bush’s ties with the mining industry. EPA administrator Christie Whitman said that the evidence was insufficient at this time to justify a $200 million annual price tag to municipalities, states and industry that would have to meet the new standard by 2006. Under pressure for ditching former President Clinton’s standard of 10 parts per billion, in April 2001 the Bush Administration committed to arrive at a solution within nine months that protects the environment and health of all Americans.
The most well known arsenic poisoning site in the world is Bangladesh. It has drawn worldwide concern and many have made efforts to remedy the problem. The World Health Organisation developed an arsenic standard meant to be a guideline for nations. In 1993 the Guidelines established 0.01 mg/L as a provisional standard. The earlier standard was 0.05 mg/L which has been the national target for many countries including Bangladesh. Well drilling and population increase has worsened the arsenic problem in the past 25 years. Perhaps the greatest obstacle to fighting the effects of the poison is the pervasive ignorance of its harm and proper treatment. The Global Applied Research Network (GARNET) recently reported that only 20% of local nongovernmental organizations had any significant information about the extent and nature of the problem. It is estimated that at least 100,000 severe cases of skin lesions have already occurred.
Problems were first suspected in Bangladesh after doctors noticed a growing number of skin lesions caused by arsenic in West Bengal, India, in 1983. More than 200,000 cases of poisoning were found from the exposure of over 1.5 million people. One of the main contributors to this occurred before the arsenic problem was even suspected. For the last 20 years in Bangladesh millions of tube-wells have been drilled less than 200 meters into the ground in an effort to provide drinking water free of various diseases. Ironically these tube-wells were carrying arsenic-contaminated water into drinking sources. Tests were not even capable of detecting it until the wells were already contaminated.
Contaminated well water poses the biggest threat of arsenic in Bangladesh. More than 2.5 million wells provide water to over 95% of the population. The wells were thought to be safe until the discovery of arsenic contaminants in 1993. The two causes generally thought to release the arsenic are pyrite oxidation and oxyhydroxide reduction. It is generally agreed that most of the contamination is due to the latter natural geological causes, and recently a public health measure has been coupled with sanitation measures to significantly decrease disease. One solution put forth to address water poisoning is field testing kits. These are readily available on a number of Internet sites, but have yet to be used widely in Bangladesh.
Efforts involving both governmental and private organisations have begun and produced new treatment technologies. The Minister of Health & Family Welfare (MHFW) created the Governmental Arsenic Co-ordinating Committee and several sub-committees to address specific technical issues. While much progress has been made, a severe disparity still exists across the nation. The World Bank gave a $32.4 million credit to Bangladesh in August 1998, and many would like to see the government move toward more effective facilitating of services to local communities that are willing to invest in water sanitation measures but lack the opportunity to do so. Without any major efforts that would most likely be planned and facilitated by the government, few options remain to provide safe water.
Arsenic has been found in the ground water of Argentina, Chile, India, Mexico, Taiwan, and Thailand among others. The symptoms occurring from arsenic poison are similar if not identical to those reported in Bangladesh, but nowhere near as severe. In countries where long-term exposure to high levels of arsenic in drinking water has been documented, studies show that one in ten cases is likely to develop into cancer. Taiwan, Chile, and Argentina have all shown increases in these cases. The Asia Arsenic Network, established in 1994, brings together professionals supporting the victims of the Toroku and Matsuo arsenic problem and aims at uniting professionals to remedy arsenic poisoning in Asian countries.
Arsenic poisoning in drinking water remains a global problem. As research continues to find more advanced and practical ways of detecting contaminated water sources and remedying them, public and private health organisations must seek to implement them if the hazardous consequences of arsenic poisoning are to be avoided. If governments lack the resources to immediately provide safe water, they should facilitate the engagement of the private sector and inform potential arsenic victims of the imminent dangers of contaminated water.
darkening of the skin.
the removal or loss of pigment, especially melanin.
a skin lesion that is abnormally sensitive to the effects of ultraviolet light.
peripheral vascular diseases:
general or unspecified diseases of the blood vessels outside the heart. It is for diseases of the peripheral as opposed to the cardiac circulation.
The above definitions were from The On-Line Medical Dictionary
In response to pumping, air or water with dissolved oxygen penetrates into the ground, leading to decomposition of the sulphide minerals and release of arsenic.
Arsenic is naturally transported and adsorbed onto fine-grained iron or manganese oxyhydroxides which slowly break down
The above two definitions taken from WHO Fact Sheet No 210