The program was intended to prevent people from drinking bacterially contaminated surface waters, but it unfortunately failed to test for arsenic in the groundwater.
Arsenic is sometimes found in its native (elemental) form, but it is usually combined with iron, cobalt, nickel, antimony, silver, or sulfur.
The most common mineral of arsenic is arsenopyrite, also called mispickel (FeSAs).
During the Bronze Age, arsenic often occurred as an impurity in bronze, and it hardened the alloy.
The European Union has classified elemental arsenic and arsenic compounds as "toxic" and "dangerous for the environment."
The World Health Organization recommends a limit of 0.01 milligrams per liter of arsenic in drinking water.
The northern United States, including parts of Michigan, Wisconsin, Minnesota and the Dakotas, are known to have significant concentrations of arsenic in groundwater.
Nonetheless, newly designed arsenic compounds are being used for special applications in recent years.
Inorganic arsenic and its compounds, upon entering the food chain, are progressively metabolized to a less toxic form of arsenic through a process of methylation.
Arsenic compounds have been known since ancient times.
The most notable case, in the late twentieth century, was that of a massive epidemic of arsenic poisoning in Bangladesh and neighboring countries.
Other arsenic minerals include orpiment, realgar, mimetite, cobaltite, erythrite, and annabergite.
Consumption of water with higher levels of arsenic over long periods of time can lead to the condition known as arsenicosis—chronic arsenic poisoning.
Given its high toxicity and the ease with which it could be used surreptitiously, arsenic was used in history by murderers, including members of the ruling class, to gain wealth, position, and power.
When heated rapidly, it oxidizes to arsenic trioxide; the fumes from this reaction have an odor resembling garlic.
Many other countries in South and Southeast Asia including Vietnam, Cambodia, and Tibet—are thought to have geological environments similarly conducive to the generation of high-arsenic groundwaters.
When this mineral is heated, the arsenic sublimes (goes directly from the solid to the vapor state), leaving ferrous sulfide.
Arsenic can be removed from drinking water through co-precipitation of iron minerals by oxidation and filtering.
Arsenic contamination of groundwater is a problem of concern in certain geographical locations.
Arsenic contamination of groundwater has been reported to occur in various parts of the world.
Some arsenic compounds—such as arsenite and arsenate salts—have been used as agricultural pesticides and herbicides.
Arsenic (chemical symbol As, atomic number 33) is a notoriously poisonous metalloid.
Two drugs (Salvarsan and Neosalvarsan) that were historically successful in treating syphilis and trypanosomiasis contained arsenic.
Arsenic and many of its compounds are especially potent poisons.
The word arsenic can be traced back to the Persian word ????? zarnikh (for yellow orpiment), which was adapted in Greek as arsenikon.
Multiple isotopes of arsenic are known, but nearly all of them are radioactive, with extremely short half-lives.
When this treatment fails to produce acceptable results, more of the arsenic can be removed by using specialized media to which arsenic will bind.
Researchers have devised tests for arsenic in water and ways to remove the toxic material before the water is supplied for consumption.
Growing the Brake (fern) Pteris vittata will remove arsenic from the soil.
Arsenic has been proposed as a "salting" material for nuclear weapons—that is, as an agent that could increase the radioactivity of the weapon's fallout for several hours.
The alchemical symbol for arsenic is shown below.
Other compounds, particularly sulfides of arsenic, were formerly used as pigments in paints.