What is Arsenic?

This Writing Was Written By : Md Raisul Islam Milu
Date:13-02-2010
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What is Arsenic?



Arsenic, chemical symbol as, is a metalloid solid. Its atomic number is 33, with an atomic weight of 74.92. In its standard state, it is very brittle and crystalline; arsenic sublimates when heated. That's the scientific side of arsenic, but what really makes the element a household name is the fact that it's poisonous. Arsenic has been the poison of choice for many a fictional criminal. Arsenic poisoning mainly comes from environmental causes. Contaminated air, food and water can all be a source of arsenic ingestion. It is also possible to ingest arsenic when living near improperly controlled toxic waste sites and in regions where rocks contain a high arsenic concentration. Even at levels low enough to not be toxic, arsenic has unpleasant side effects. Breathing arsenic may cause lung and throat irritation, while ingesting a smaller amount can cause nausea, vomiting and blood problems. Exposure to low levels over a longer period of time can cause darkened skin and wart-like marks. If you suspect that you have been exposed to arsenic, there are a few tests that doctors can perform. If you can get tested within a few days of the potential exposure, then a urine sample will be the best indicator of arsenic in your system. Over a longer period of 6-12 months, doctors can examine your hair and nails for indicators of high levels of arsenic in your system.

2ND

This Writing Was Written By : Md Raisul Islam Milu
Date:13-02-2010
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History of arsenic



The word arsenic was borrowed from the Persian word Zarnikh, meaning "yellow orpiment", into Greek as arsenikon. It is also related to the similar Greek word "arsenikos", meaning "masculine" or "potent". Arsenic sulfides and oxides have been known and used since ancient times. Zosimos describes roasting sandarach to obtain cloud of arsenic which he then reduces to metallic arsenic. As the symptoms of arsenic poisoning were somewhat ill-defined, it was frequently used for murder until the advent of the Marsh test, a sensitive chemical test for its presence. Owing to its use by the ruling class to murder one another and its potency and discreetness, arsenic has been called the Poison of Kings and the King of Poisons.
Cadet's fuming liquid (impure cacodyl), the first organometallic compound, was synthesized in 1760 by Louis Claude Cadet de Gassicourt by the reaction of potassium acetate with arsenic trioxide.
In the Victorian era, "arsenic" (colourless, crystalline, soluble "white arsenic" trioxide) was mixed with vinegar and chalk and eaten by women to improve the complexion of their faces, making their skin paler to show they did not work in the fields. Arsenic was also rubbed into the faces and arms of women to "improve their complexion". The accidental use of arsenic in the adulteration of foodstuffs led to the Bradford sweet poisoning in 1858, which resulted in approximately 20 deaths and 200 people taken ill with arsenic poisoning

3RD

This Writing Was Written By : Md Raisul Islam Milu
Date:13-02-2010
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Effects on human health


Arsenic is very harmful in our daily life. Long-term exposure to arsenic in drinking-water is causally related to increased risks of cancer in the skin, lungs, bladder and kidney, as well as other skin changes such as hyperkeratosis and pigmentation changes. These effects have been demonstrated in many studies using different study designs. Exposure–response relationships and high risks have been observed for each of these end-points. The effects have been most thoroughly studied in Taiwan but there is considerable evidence from studies on populations in other countries as well. Increased risks of lung and bladder cancer and of arsenic-associated skin lesions have been reported to be associated with ingestion of drinking-water at concentrations £ 50 µg arsenic/litre.
Occupational exposure to arsenic, primarily by inhalation, is causally associated with lung cancer. Exposure–response relationships and high risks have been observed. Increased risks have been observed at cumulative exposure levels ≥ 0.75 (mg/m3) × year. Tobacco smoking has been investigated in two of the three main smelter cohorts and was not found to be the cause of the increased lung cancer risk attributed to arsenic; however, it was found to be interactive with arsenic in increasing the lung cancer risk.
Even with some negative findings, the overall weight of evidence indicates that arsenic can cause clastogenic damage in different cell types with different end-points in exposed individuals and in cancer patients. For point mutations, the results are largely negative.

4TH

This Writing Was Written By : Md Raisul Islam Milu
Date:13-02-2010
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Global situation


The delayed health effects of exposure to arsenic, the lack of common definitions and of local awareness as well as poor reporting in affected areas are major problems in determining the extent of the arsenic-in-drinking-water problem.
Reliable data on exposure and health effects are rarely available. These include Argentina, Australia, Bangladesh, Chile, China, Hungary, India, Mexico, Peru, Thailand, and the United States of America. Countries where adverse health effects have been documented include Bangladesh, China, India, and the United States of America. Examples are:
• Seven of 16 districts of West Bengal have been reported to have ground water arsenic concentrations above 0.05 mg/L; the total population in these seven districts is over 34 million (Mandal, et al, 1996).
• According to a British Geological Survey study in 1998 on shallow tube-wells in 61 of the 64 districts in Bangladesh, 46% of the samples were above 0.010 mg/L and 27% were above 0.050 mg/L. When combined with the estimated 1999 population, it was estimated that the number of people exposed to arsenic concentrations above 0.05 mg/l is 28-35 million and the number of those exposed to more than 0.01 mg/l is 46-57 million.
• Environment Protection Agency of The United States of America has estimated that some 13 million of the population of USA, mostly in the western states, are exposed to arsenic in drinking- water at 0.01 mg/L, although concentrations appear to be typically much lower than those encountered in areas such as Bangladesh and West Bengal.

Prevention and control

This Writing Was Written By : Md Raisul Islam Milu
Date:13-02-2010
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Prevention and control



Arsenic control is very very essential matter in the world. The most important remedial action is prevention of further exposure by providing safe drinking- water. The cost and difficulty of reducing arsenic in drinking-water increases as the targeted concentration lowers.
Control of arsenic is more complex where drinking-water is obtained from many individual sources as is common in rural areas. Low arsenic water is only needed for drinking and cooking. Arsenic-rich water can be used safely for laundry and bathing.
Alternative low-arsenic sources such as rain water and treated surface water may be available and appropriate in some circumstances. Where low arsenic water is not available, it is necessary to remove arsenic from drinking-water:
• The technology for arsenic removal for piped water supply is moderately costly and requires technical expertise. It is inapplicable in some urban areas of developing countries and in most rural areas world-wide.
• New types of treatment technologies, including co-precipitation, ion exchange and activated alumina filtration are being field-tested.
• There are no proven technologies for the removal of arsenic at water collection points such as wells, hand-pumps and springs.
• Some studies have reported preliminary successes in using packets of chemicals for household treatment. Some mixtures combine arsenic removal with disinfection. One example, developed by the WHO/PAHO Pan American Center of Sanitary Engineering and Environmental Sciences in Lima, Peru, has proven successful in Latin America.