Arsenic

Arsenic is a naturally occurring element found in earth's crust. It is an odorless and tasteless semi-metal element. In the Periodic Table, its symbol is As and its atomic number is 33. Although arsenic is toxic to humans, it is used in a number of industries and released into the environment. As a result, arsenic has been found in sewage sludge. The U.S. EPA limits the maximum allowed concentration of arsenic in drinking water to 0.010 parts per million (10 parts per billion). In sewage sludge applied to land, the U.S. EPA limits arsenic to a concentration of 75 parts per million.

Uses

In the U.S. arsenic is mostly used as a wood preservative, but it is also used in paints, dyes, metals, drugs, soaps, and semi-conductors. Arsenic is also released into the environment by copper smelting, mining, and coal burning. As broilers, chickens raised for meat, are commonly given the arsenical roxarsone to prevent chickens from getting parasitic diseases. Use of roxarsone results in the presence of arsenic in chicken manure, which is in turn often used as a fertilizer.

Historical Use as a Pesticide

During the latter half of the 19th century and the first half of the 20th century, arsenicals like Paris green, lead arsenate, and calcium arsenate were popular and common pesticides used in agriculture. Use of arsenical pesticides began in 1867, when Paris green proved effective against the Colorado potato beetle. Acceptance grew slowly, as many were wary of putting such a toxic substance on food. The first arsenicals used were waste products. Paris green was derived from flue ash and mining and was then used in green paint. Another popular arsenical pesticide, London purple, was a dye used by the garment industry. (London purple went in and out of vogue in the 1890s; it was easier to use in a spray pump than Paris green and it dyed the plants purple - conveniently letting farmers know when to spray again, when the plants were no longer purple - but it tended to kill the plants as well as the bugs.) Lead arsenate came into vogue in the 1890's as well, when it was found to work against the gypsy moth, an invasive pest in New England. By 1900, Paris green and London purple were almost completely replaced by lead arsenate and calcium arsenate, with lead arsenate typically used on fruits and vegetables and calcium arsenate preferred for cotton.

The widespread use of arsenicals continued until the 1950's. During this time, many farm children died from arsenic poisoning. According to Will Allen, author of The War on Bugs: "Nevertheless, since this toxic metal also proved very effective against so many hard-to-kill pests, many users overlooked its lethal dangers to their children. Instead of eliminating arsenic from their chemical sheds, farmers threatened their children with harsh punishment if they went anywhere near the shed."

In the 1890's, food poisonings from arsenic also began to occur. After 1900, media reports of arsenic poisoning were quite frequent. By 1920, a large percent of the U.S. population began showing symptoms of both arsenic and lead poisoning. By the 1930's, over 100 million Americans suffered from mild to severe arsenic and lead poisoning.

Opposition to arsenic and lead pesticides began in the 1890's in response to poisonings. In 1903, the UK set residue limits for arsenic and lead in food and beer. In the US, the Food and Drug Administration (FDA) was created in 1906 to ensure the health and safety of food. However, because it was initially placed under the USDA, which supported the use of pesticides, the FDA did very little to regulate pesticide use. In the U.S., the tide began to turn against arsenic and lead pesticides in the 1930's, when pests were showing resistance to the poisons and the public was increasingly opposed to their use. Still, companies sold the pesticides, farmers used them, and the government - which occasionally warned about restricting arsenic and lead as pesticides in the 1930's - still did nothing.

After World War II, arsenical pesticides were essentially replaced with DDT and other organochlorines, although some uses of arsenicals continued.

21st Century Use as a Pesticide

In 2008, author Will Allen wrote that the use of arsenicals continues today, in roxarsone given to chickens, and as a cotton defoliant and weed killer. At that time, arsenic was used in the forms of calcium arsenate, arsenic acid, cacodylic acid, DSMA (disodium methanearsonate), MAMA (monoammonium methanearsonate), and MSMA (monosodium methanearsonate), all of which are used on food except MAMA, "which is used on turf grass that kids play on and eat picnics on." Since that time, some - but not all - of these uses have been phased out in the U.S.

EPA Caves to Industry Pressure

In 2006, the U.S. EPA made a "Reregistration Eligibility Decision" (RED) for the organic arsenical pesticides MSMA, DSMA, CAMA (calcium acid methanearsonate), and cacodylic acid and its sodium salt, essentially banning all of these chemicals from use as a pesticide in the U.S. This is because "following application, these pesticides convert over time to a more toxic form in soil, inorganic arsenic, and potentially contaminate drinking water through soil runoff." EPA was also concerned that MSMA, which is used on cotton, could enter the human food supply "through the meat and milk of animals fed cotton by-products (seeds, hulls, and gin by-products) that have been treated with MSMA."

In the two years following the decision, "stakeholders" (presumably the chemical and agribusiness industries) lobbied the EPA that "no residues of inorganic arsenic are likely to remain in the meat and milk of animals fed cotton by-products that have been grown in fields treated with MSMA, or in food crops that are rotated with cotton that has been treated with MSMA." Also, cotton growers complained of glyphosate resistance in Palmer amaranth (pigweed), a cotton weed, saying they had no alternatives to MSMA to control it.

Thus, in 2009, the EPA went back on their previous decision to ban the named organic arsenical pesticides for all uses, instead allowing the continued use of MSMA on cotton. The timeline of the phaseout of these pesticides is as follows:

• By the end of 2009, the organic arsenicals named above were no longer allowed for use on residential lawns, forestry, non-bearing fruit and nut trees, citrus orchards (bearing and non-bearing), and drainage ditches.

• Use of MSMA on golf courses, sod farms, and highway rights-of-way will end on December 31, 2012, with use of existing stocks permitted through 2013.

Until their 21st century phaseout, MSMA, DSMA, or CAMA were sold under the trade names Scotts Post Emergent Crabgrass Control, Gordon’s Crabgrass and Nutgrass Killer, and Ferti-Lome Crabgrass, and Dallis Grass Killer. Cacodylic acid was sold as Scotts Spot Grass & Weed Control, Liquid Edger, and Liquid Fence & Grass Edger.

Arsenical Pesticides: Still Legal Today

As of 2010, a few forms of arsenic are still legal for use in the United States. As noted above, MSMA is still permitted on cotton indefinitely, and it is also legal on golf courses, sod farms, and highway rights-of-way until the end of 2013. Additionally, arsenic acid, an inorganic arsenic, is still permitted for use in the United States as an herbicide, insecticide, and rodenticide. Arsenic pentoxide, another inorganic arsenic, is legal as well as a fungicide, herbicide, insecticide, and rodenticide. Last, roxarsone, an arsenical, is still legal for use in chickens as of 2011, but the FDA has begun taking some action which may result in a ban on this drug.

Presence in the Environment

Both natural activities (volcanic action, erosion of rocks, or forest fires) and human activities can release arsenic into the atmosphere. Widespread industrial use contributes to arsenic pollution in the environment. Arsenic has been found in sewage sludge. Arsenic in water is deposited in soil or sediment and therefore it can also be present in food and water. In the Targeted National Sewage Sludge Survey, a 2009 test of 84 samples of sewage sludge from around the U.S., the EPA found arsenic in every sample in concentrations ranging from 1.18 to 49.2 parts per million.

Toxicity

According to the Agency for Toxic Substances "Ingesting very high levels of arsenic can result in death. Breathing high levels of inorganic arsenic leads to irritated lungs." The World Health Organization cites "overwhelming evidence from epidemiological studies that consumption of elevated levels of arsenic through drinking-water and other sources is causally related to the development of cancer at several sites, particularly skin, bladder and lung."

Arsenic and coal

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Arsenic on your cereal?

Arsenic is found in coal and coal waste. It is the most common cause of acute heavy metal poisoning in adults, and does not leave the body once it enters.

In October 2009, the EPA sent the White House a Notice of Proposed Rulemaking for toxic coal ash. President Obama's choice as the head of the White House Office of Management and Budget, Cass Sunstein, oversees such policies, but has refused to act on the EPA's plea. In December 2009, there was a Congressional hearing in the House Energy and Commerce Subcommittee on "Drinking Water and Public Health Impacts of Coal Combustion Waste Disposal," largely in response to the 2008 TVA Kingston Fossil Plant coal ash spill and EPA reports on the health and environmental risks of coal ash and coal waste. Dr. Donald McGraw, the GOP's expert witness at the hearing, testified that arsenic is natural and coal waste benign, as seen in this video.

According to reports filed with the EPA by the Tennessee Valley Authority, the 2008 TVA Kingston Fossil Plant coal ash spill resulted in a discharge of 140,000 pounds of arsenic into the Emory River -- more than twice the reported amount of arsenic discharged into U.S. waterways from all U.S. coal plants in 2007.

On March 8, 2010 it was announced that the South Carolina Department of Health and Environmental Control agreed to eliminate arsenic limits in a wastewater discharge permit for South Carolina Electric & Gas Company's (SCE&G) Wateree Station. SCE&G needs State approval for its coal ash ponds because wastewater from the site runs directly into the Wateree River. The ponds take waste from the company's 40-year-old coal-fired plant. Since the 1990s, high levels of arsenic, a carcinogen, have been found in groundwater and in seepage to the Wateree River from coal ash ponds at the power plant. Sierra Club and other environmental groups are posing to fight the permit on the grounds that arsenic ought not be eliminated.

A 2010 EPA report, "Human and Ecological Risk Assessment of Coal Combustion Wastes", found that people who live near coal ash impoundments and drink from wells have as much as a 1 in 50 chance of getting cancer from arsenic contamination, as well as an increased risk of damage to the liver, lungs, kidneys and other organs.

A 2011 Environmental Integrity Project (EIP) monitor identified 19 new sites across the U.S. where groundwater near coal-ash dumps was found to be contaminated with arsenic and other pollutants. The EPA in 2007 had documented 67 potential damage cases. EIP said the pollution at the new sites was in some cases more than 10 times the maximum contaminant level for arsenic, as well as several other pollutants including lead, barium, cadmium, and boron. The study focuses in particular on coal ash and ash recycling like structural fill; one site, an urban rail trail in Indiana which uses recycled coal-ash, has soil contaminated with arsenic 900 times the federal screening level, the report said.

Articles and resources

Related GEM.wiki articles

• Biosolids
• Sewage sludge
• Food Rights Network
• Heavy metals and coal

External resources

• World Health Organization, "Chemical hazards in drinking-water - arsenic".

External articles

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