Arsenic poisoning is a medical condition caused by increased levels of the element arsenic in the body. Arsenic interferes with cellular longevity by allosteric inhibition of an essential metabolic enzyme.

Routes of exposure include contaminated water, air, and food. Occupational exposure to arsenic may occur with copper or lead smelting and wood treatment and among workers involved in the production or application of pesticides.

Symptoms

Symptoms of arsenic poisoning begin with headaches, confusion, severe diarrhea, and drowsiness. As the poisoning develops, convulsions and changes in fingernail pigmentation called leukonychia may occur. When the poisoning becomes acute, symptoms may include diarrhea, vomiting, blood in the urine, cramping muscles, hair loss, stomach pain, and more convulsions. The organs of the body that are usually affected by arsenic poisoning are the lungs, skin, kidneys, and liver. The final result of arsenic
poisoning is coma to death.

Arsenic is related to heart disease (hypertension related cardiovascular), cancer, stroke (cerebrovascular diseases), chronic lower respiratory diseases, and diabetes.

Long term exposure to arsenic is related to vitamin A deficiency which is related to heart disease and night blindness.

Causes

In addition to its presence as a poison, for centuries arsenic was used medicinally. It has been used for over 2,400 years as a part of traditional Chinese medicine. In the western world, arsenic was used extensively to treat syphilis before penicillin was introduced. It was eventually replaced as a therapeutic agent by sulfa drugs and then by antibiotics. Arsenic was also an ingredient in many tonics (or patent medicines).

In addition, during the Elizabethan era, some women used a mixture of vinegar, chalk, and arsenic applied topically to whiten their skin. This use of arsenic was intended to prevent aging and creasing of the skin, but some arsenic was inevitable absorbed into the blood stream.

Some pigments, most notably the popular Emerald Green (known also under several other names), were based on arsenic compounds. Overexposure to these pigments was a frequent cause of accidental poisoning of artists and craftsmen. One of the biggest unintentional cases of arsenic poisoning via well water consumption is in Bangladesh and called by the World Health Organization as the largest mass poisoning of a population in history.

Research has shown that the inorganic arsenites (trivalent forms) in drinking water have a much higher acute toxicity than organic arsenates (pentavalent forms). The acute minimal lethal dose of arsenic in adults is estimated to be 70 to 200 mg or 1 mg/kg/day. Most reported arsenic poisonings are caused by one of arsenics compounds, also found in drinking water, arsenic trioxide which is 500 times more toxic than pure arsenic.

Occupational exposures

Industries that use inorganic arsenic and its compounds include wood preservation, glass production, nonferrous metal alloys, and electronic semiconductor manufacturing. Inorganic arsenic is also found in coke oven emissions associated with the smelter industry.

Occupational exposure to arsenic may occur with copper or lead smelting and wood treatment, among workers involved in the production or application of pesticides containing organic arsenicals. Humans are exposed to arsenic through air, drinking water, and food (meat, fish, and poultry); poultry is usually the largest source of food-based arsenic ingestion due to usage of certain antibiotics in chicken feed. Arsenic was also found in wine if arsenic pesticides are used in the vineyard. Arsenic is well absorbed by oral and inhalation routes, widely distributed and excreted in urine; most of a single, low-level dose is excreted within a few days after consuming any form of inorganic arsenic. Remains of arsenic in nails (which show as white spots and lines) and hair can be detected years after the exposure.

Drinking water

Chronic arsenic poisoning results from drinking contaminated well water over a long period of time. This is due to arsenic contamination of aquifer water. The World Health Organization recommends a limit of 0.01 mg/L (10ppb) of arsenic in drinking water. This recommendation was established based on the limit of detection of available testing equipment at the time of publication of the WHO water quality guidelines. More recent findings show that consumption of water with levels as low as 0.00017 mg/L (0.17ppb) over long periods of time can lead to arsenicosis.

From a 1988 study in China, the US protection agency quantified the lifetime exposure of arsenic in drinking water at concentrations of 0.0017 mg/L, 0.00017 mg/L, and 0.000017 mg/L are associated with a lifetime skin cancer risk of 1 in 10,000, 1 in 100,000, and 1 in 1,000,000 respectively. The World Health Organization contends that a level of 0.01 mg/L poses a risk of 6 in 10000 chance of lifetime skin cancer risk and contends that this level of risk is acceptable.

Food
China is the only country to have set a standard for arsenic limits in food, as levels in rice exceed those in water. It has been found that rice is particularly susceptible to arsenic poisoning. Rice grown in US has an average 26 ppb of arsenic according to a study.

Western Medicine Treatment

Chelation

Chemical and synthetic methods are now used to treat arsenic poisoning. Dimercaprol and dimercaptosuccinic acid are chelating agents which sequester the arsenic away from blood proteins and are used in treating acute arsenic poisoning. The most important side effect is hypertension. Dimercaprol is considerably more toxic than succimer.

Mineral supplements

Supplemental potassium decreases the risk of experiencing a life-threatening heart rhythm problem from arsenic trioxide.

Nutritional intervention

In the journal Food and Chemical Toxicology, Keya Chaudhuri of the Indian Institute of Chemical Biology in Kolkata, and her colleagues reported giving rats daily doses of arsenic in their water, in levels equivalent to those found in groundwater in Bangladesh and West Bengal. Those rats which were also fed garlic extracts had 40 percent less arsenic in their blood and liver, and passed 45 percent more arsenic in their urine. The conclusion is that sulfur-containing substances in garlic scavenge arsenic from tissues and blood. The presentation concludes that people in areas at risk of arsenic contamination in the water supply should eat one to three cloves of garlic per day as a preventative.

Adopted from mayocllinic.com