Arsenic, element #33, has long been known for its use as a [poison]. Cesare Borgia and his family used arsenic to consolidate power in 16th century Italy and it is rumored that Napoleon Bonaparte may have been poisoned with arsenic.
From emedicine
:
Arsenic has been used as a medicinal agent, a pigment, a pesticide, and an agent of criminal intent. It is typically considered a heavy metal and shares many toxic characteristics with the other heavy metals (eg, lead, mercury). Arsenic is primarily used in the production of glass and semiconductors. It is also found in certain water supplies and seafood.
Arsenic exposure today most often results from industrial practices such as the smelting process overexposure to treated wood.
|
Just the facts
| Physical Information |
| Name: Arsenic |
| Use: wood preservative, pesticides, semiconductor manufacturing |
| Source: coal combustion, drinking water, environment, medical drug, seafood |
| Recommended daily intake: none (not essential) |
| Absorption: inhalation, intestine - inorganic high, organic low, skin |
| Sensitive individuals: children |
| Toxicity/symptoms: periphal nervous system (tingling in hands and feet), skin cancer (ingestion), lung cancer (inalation), hyperpigmentation (keratosis) of palms and soles; vascular complications |
Regulatory facts:
- EPA - drinking water 10 ug/L (0.01 ppm)
- EPA - RfD - 0.3 ug/kg/ day
- OSHA - Workplace air 10 ug/m3
- ATSDR - MRL - 0.3 ug/kg/day
|
| General facts: long history of use as medicine and poison |
| Environmental: global environmental contaminant, bioaccumulates in fish and shellfish (mostly in a form that is not harmful) |
| Recommendations: avoid, do not use treated lumber, test drinking water |
|
|
Chemical Description
Arsenic is a versatile metal, forming various compounds, inorganic or organic, with a complex chemistry. Inorganic arsenic is widely distributed in nature, usually in the trivalent form (As3+) bet also pentavalent arsenic (As5+). The trivalent forms include arsenic trioxide, sodium arsenite, and arsenic trichloride. Organic arsenic is much less toxic than inorganic and it is produced in a biomethylation process by many organisms including shellfish and humans. It does not bioaccumulate in the food chain.
Arsenic is also very similar to Phosphorous.
Arsenic in Drinking Water
Arsenic poisoning from drinking water remains a very serious world health issue. Internationally, in West Bengal, India and Bangladesh more than 75 million people are exposed to arsenic-laden drinking water that threatens their health. Of those 75 million, it is estimated that 200,000 to 270,000 people will die from cancer each year (Gilbert, 2004.
High levels of arsenic in drinking water often results from high levels of arsenic in nearby soil or rocks. The US EPA has recently took a tougher stance on arsenic by lowering the standard from 50 ppm to 10 ppm. This standard is constantly being lowered because chronic exposure to low levels of arsenic can be fatal as well.
Arsenic in the Environment
Arsenic is a ubiquitous element in the natural environment. It is a naturally occurring metal and its organic form, found when arsenic is combined with carbon or [hydrogen] is not as common as inorganic arsenic which occurs when arsenic combined with one or more elements including oxygen, chlorine, and sulfur. The amount of arsenic released from ore bodies is mush less than the amount of arsenic released due to human activity.
All rocks and soil contain some level of arsenic. Most rocks contain between 1-5 ppm or arsenic and this arsenic leaches into the soil. The rocks also leach arsenic into groundwater sources and depending on the type of rocks, arsenic can build up to critical levels in some sources. Up to 40 million people are at risk of drinking arsenic laden water in Bangladesh.
Though, arsenic is naturally occurring in soil, most areas with problematic levels of arsenic exposure are a result of human activity. The majority of arsenic released into the environment is from the industrial smelting or coal burning processes. By burning the ores that contain some amount of arsenic, because it is ubiquitous and highly reactive, the smoke that is produced is inundated with arsenic which travels downwind and settles in the soil or water (Roy and Saha, 2002).
Arsenic has been used as a herbicide and insecticide in the past so the areas where it was applied, most commonly orchards, possess elevated levels. Arsenic readily contaminates other ores. Areas around gold, copper, and zinc mines are often places that find the highest concentration of arsenic in the soil.
Until recently, arsenic was added to wood|treated wood] to protect it from fungus and decay. This arsenic easily escapes onto people who are in direct contact with the wood. Walking on the wood barefoot or splinters from the treated wood pose a serious health problem and, even though production of the wood has stopped, it will still be present in structures for years to come.
Uses
Insecticide
Different forms of arsenic have been used as insecticides (lead hydrogen arsenate on fruit trees and later monosodium methyl arsenate). Using arsenic as an insecticide has caused elevated levels in the soil in areas where it was applied in the past.
Poison
Main article: Arsenic Poisoning
Arsenic also has been used in the past as a poison. Napoleon's Death by Arsenic Exposure...? by arsenic poisoning was long been suspected.
Treated Wood
But by far the largest use of arsenic is in treating wood to prevent decay or damage from insects. The compound used is the pesticide chromated copper arsenate (CCM). CCM is a tonic of inorganic salts of chromium, Copper, and [arsenate] that is forced into the wood under intense pressure. This wood has traditionally been used in decks, playground equipment, outdoor furniture and fences, construction lumbar, pilings, poles, and any number of other instances when the wood will be exposed to the elements. A standard 8 foot 2 x 4 can have up to 15 grams of arsenic.
Though the health effects of treated wood have been debated by the government, environmental agencies, and the lumber industry, research has shown that treated wood can in fact be quite dangerous. The biggest hazard is if one inhales sawdust that had been treated. Also, research has shown that the arsenic can leach from the wood or be rubbed off the surface. Therefore, children who are in contact with this wood are at a high risk as well.
Manufacturers of this wood reached an agreement with the Environmental Protection Agency to phase out residential use of treated wood but still use it for commercial purposes.
Medical Uses
Many different arsenic compounds have been used, some until quite recently, in medicine throughout the world. [Potassium arsenite], [arsenic iodide], and [arsenic trichloride] were used regularly to treat a range of illnesses and arsphenamine was the main drug used to treat [syphilis]. Arsenic trioxide was the main ingredient of the popular tonic of the 19th century, Fowler's Solution (Roy and Saha, 2002).
Arsenic is still used in some places in India to control blood counts of patients with hematological malignancies and in many different herbal remedies in China (Roy and Saha, 2002).
Toxicity
The Agency for Toxic Substances and Registry (ATSDR) of the United States ranked arsenic first in its list of the twenty most hazardous substances. Its toxicity is hard to investigate because of its ability to convert between oxidation states and organometalloidal forms (Roy and Saha, 2002). The symptoms of exposure, both acute and chronic, are highlighted below.
Health Effects
Main Article: Arsenic Poisoning
The acute effects of inorganic arsenic poisoning are well known because of the high number or suicides and poisonings which have employed arsenic in history. Ingestion of 70-180 mgs of arsenic can be fatal, but the initial effects may be delayed for hours. The symptoms following oral ingestion include throat constriction and difficulty breathing and swallowing, severe intestinal pain, vomiting, diarrhea, muscle cramps, severe thirst, coma, and death.
The symptoms of chronic arsenic exposure are often associated with contaminated drinking water. The earliest sign of exposure are a garlic odor on the breath, extreme perspiration, muscle tenderness and weakness, and changes in skin pigmentation. More progressive signs include anemia, reduced sensation in the hands and feet from damage to the peripheral nervous system (stocking and glove syndrome), peripheral vascular disease, skin changes on palms and soles, and liver and kidney involvement. Changes in circulation can eventually lead to gangrenous afflictions. hyperpigmentation and hyperkeratosis of palms and soles occurs in 3-6 months with repeated ingestion of 0.4 mg/kg per day. Therefore, repeated low levels of arsenic exposure can result in similiar conditions to acute poisoning.
Classifying arsenic as a carcinogen has been difficult because it does not cause cancer in rodents, but has been shown to cause cell proliferation, chromosome abnormalities, and modification of gene expression (Roy and Saha, 2002). Therefore its carcinogenicity was not able to independently verified in testing on lab animals, though studies on human cells and then observations of people who have been exposed to increased levels of arsenic (many in West Bengal, India and Bangladesh) have led to a widespread belief in the scientific community that arsenic is in fact a carcinogen (Roy and Saha, 2002).
Precautions
There are many ways to reduce exposure to arsenic:
- Wash hands and face and those of children after playing outside and before eating
- Clean home regularly using a damp mop or cloth. Vacuuming and sweeping can increase dust levels in the home. Use a phosphate cleaner at least once a week, especially near windows and doors.
- Avoid bringing dirt into the house.
- Brush pets often to minimize the dust they bring into the house.
- Keep children's toys and play area clean and discourage mouthing activities such as eating dirt or sucking on dirty objects.
- Wash all vegetables thoroughly and peel root crops.
- Wear gloves and masks if digging or excavating
- Use water filters to limit the amount of arsenic in the drinking water.
- Reduce exposure to treated wood.
- Do not burn treated wood.
Current Events
March 14, 2008
Arsenic-bearing children's drinks produced in United States find their way to Canadian store shelves. See full Ottawa Citizen article
September 14, 2006
Experts have testified to say arsenic has been shown to be a carcinogen. Article is from March 10, 2007 Baltimore Sun.
September 3, 2006
South Bend, Indiana may face huge costs in removing arsenic from local waterway. See South Bend Tribune article
Regulations
Arsenic regulations were set in 1903 in England around at around 90 ppb though this level was decreased by half in the next century until the United States, England, and Bangladesh (see Arsenic Poisoning in Bangladesh for an overview of their arsenic-related problems) all set the arsenic level ceiling at around 50 ppb (Harvard, 2007). Later this number was reduced again to around 10 ppb.
History
Arsenic has a long and diverse history of use. It is undoubtedly most well known as a poison, having been used since the Romans to the mid-19th century. Its lack of color, odor, and taste made it a favorite means of disposing of one's enemy by merely putting a few drops in a wine glass. When ingested in high quantities, it causes severe abdominal cramps, diarrhea and vomiting, and eventually death. But it can also be administered in small doses, making the victim look as if he/she is suffering from some chronic illness and thus disguising the assassin's intent. Arsenic poisoning was such a widespread concern, the Roman Consul Lucius Cornelious Sulla issued the Lex Cornelia in 82 B.C. outlawing poisoning.
Though Sulla was the first to make illegal arsenic poisoning, another group of Italians will forever be remembered for their rampant arsenic use to consolidate power and become rich. [The Borgias], led by [Cesere Borgia] and his father Pope Alexander VI, assassinated numerous wealthy cardinals and popes and, by church law, received the deceased holdings and money. They used these practices to become some of the richest men in all of Italy, until they themselves succumbed to the poison.
Arsenic has been used in the past for numerous industrial and agricultural purposes, though its use is much more infrequent and often times nonexistent in a number of capacities that it was formally employed. It was at one time used as an insecticide, herbicide, wood preservative, and numerous other industrial applications including in wallpaper and in paint pigments. Up until 2003, [chromated copper arsenic] was added to wood to help prevent decay and ward off fungus.
Additionally, arsenic was used in many tonics and medicines in the past. The most well-known treatment of arsenic was [Fowler's Solution, a tonic that contained one-percent potassium arsenite that was widely used as cure-all through the 19th century. Arsenic was also briefly used as a chemical weapon. The Germans developed the [blister agent] [lewescite] though it was never employed in battle.
Teaching Resources
Powerpoint presentation on Arsenic
External Links
European, Asian, and International Agencies
North American Agencies
Non-Government Organizations
References
Harvard Arsenic Foundation. "Chronic Arsenic Poisoning: History, Study and Remediation". Accessed 4-26-07.
Washington State Dept. of Health Report on Arsenic in the Environment.
University of Otago Geology Report on Arsenic int he Environment
Water Arsenic Exposure and Children's Intellectual Function in Araihazar, Bangladesh (2004) Gail A. Wasserman, X. Liu, F. Parvez, H. Ahsan, P Factor-Litvak, A. van Geen, V. Slavkovich, N. J. LoIacono, Z. Cheng, I. Hussain,5 H. Momotaj, and J. Graziano. Environ Health Perspect 112:1329-1333 (2004). EHP Online. (accessed: 14 December 2004)
Environmentally healthy homes and communities. Children's special vulnerabilities. (2001). Am Nurse, 33(6), 26-38; quiz 39-40.
Gilbert, Steven G. "A Small Dose of Toxicology: The Health Effects of Common Chemicals." New York: CRC Press, 2004.
Hall, A. H. (2002). Chronic arsenic poisoning. Toxicol Lett, 128(1-3), 69-72.
Jiang, J. Q. (2001). Removing arsenic from groundwater for the developing world--a review. Water Sci Technol, 44(6), 89-98.
Liu, J., Zheng, B., Aposhian, H. V., Zhou, Y., Chen, M. L., Zhang, A., & Waalkes, M. P. (2002). Chronic arsenic poisoning from burning high-arsenic-containing coal in Guizhou, China. Environ Health Perspect, 110(2), 119-122.
Pott, W. A., Benjamin, S. A., & Yang, R. S. (2001). Pharmacokinetics, metabolism, and carcinogenicity of arsenic. Rev Environ Contam Toxicol, 169, 165-214.
Pradosh Roy and Anupama Saha, ["Metabolism and Toxicity of Arsenic: A Human Carcinogen"],
Current Science 82, (January 2002), p. 38-45.