chemistry

Roxarsone

Roxarsone is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Roxarsone rather than just read about it. In short: Roxarsone is an organoarsenic compound that has been used in poultry production and to a lesser extent in pig production as a feed additive to increase weight gain, for greater feed efficiency, to improve pigmentation, and as a coccidiostat. Until June 2011, it was approved for use in the United States, Canada, Australia, and 12 other countries.

Key takeaways

Roxarsone belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Roxarsone to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Roxarsone from memory before moving on to harder problems.

Reference excerpt

Roxarsone is an organoarsenic compound that has been used in poultry production and to a lesser extent in pig production as a feed additive to increase weight gain, for greater feed efficiency, to improve pigmentation, and as a coccidiostat. Until June 2011, it was approved for use in the United States, Canada, Australia, and 12 other countries. It is no longer approved for use in most jurisdictions. Roxarsone has been banned in the European Union since 1999. Its use in the United States was voluntarily ended by the manufacturers in June 2011, and it has been illegal since 2013. Its use was suspended in Malaysia in June 2011. It was banned in Canada in August 2011. In Australia, its use was discontinued in 2012.

Production and applications Roxarsone is a derivative of phenylarsonic acid (C6H5As(O)(OH)2). It was first reported in a 1923 British patent that described the nitration and diazotization of arsanilic acid. When blended with calcite powder, it is used in poultry feed premixes in some parts of the world. Where available, it can be purchased in 5%, 20% and 50% concentrations. Roxarsone was marketed as 3-Nitro by Zoetis, a former subsidiary of Pfizer now a publicly traded company. In 2006, approximately one million kilograms of roxarsone were produced in the U.S.

Marketing approval in the United States Roxarsone is one of four arsenical animal drugs that had been approved by the U.S. Food and Drug Administration (FDA) for use in poultry and swine, along with nitarsone, arsanilic acid, and carbarsone. In September 2013, the FDA announced that Zoetis and Fleming Laboratories would voluntarily withdraw current roxarsone, arsanilic acid, and carbarsone approvals, leaving only nitarsone approvals in place. In 2015, the FDA withdrew the approval of using nitarsone in animal feeds. The ban came into effect at the end of 2015.

Controversy Roxarsone has attracted attention as a source of arsenic contamination of poultry and other foods. In June 2011, the manufacturers suspended sales of roxarsone in the U.S. and Canada in response to a study by the Food and Drug Administration (FDA) that found that roxarsone use was associated with elevated levels of inorganic arsenic in chicken livers. An FDA press release stated that the findings raised "concerns of a very low but completely avoidable exposure to a carcinogen." A 2013 market basket study conducted in the United States linked the use of roxarsone and other arsenical feed additives to increased levels of inorganic arsenic in chicken breast meat. The study was performed on chickens raised prior to the voluntary withdrawal of roxarsone from the market by its manufacturer. Breast meat from chickens exposed to arsenical feed additives contained inorganic arsenic at the level of about two parts per billion. Breast meat from chickens raised in farms with a policy not to use arsenical feed additives contained inorganic arsenic at the level of 0.7 parts per billion. Organic chickens are not exposed to arsenical feed additives and contained about half a part per billion. Federal standards at the time permitted concentrations of 500 parts per billion of total arsenic, but were established before 1963 and did not differentiate between organic arsenic and its highly toxic inorganic variety. In February 2011 the FDA's Center for Veterinary Medicine recommended inorganic arsenic in chicken not exceed 1 part per billion, then revised the statement to remove language suggesting a safe concentration, noting: "any new animal drug that contributes to the overall inorganic arsenic burden is of potential concern."

References

Further reading J. R. Garbarino; A. J. Bednar; D. W. Rutherford; R. S. Beyer & R. L. Wershaw (2003). "Environmental Fate of Roxarsone in Poultry Litter. I. Degradation of Roxarsone during Composting". Environ. Sci. Technol. 37 (8): 1509–1514. Bibcode:2003EnST...37.1509G. doi:10.1021/es026219q. PMID 12731831. Chiou P. W.-S.; Chen K.-L.; Yu B. (1997). "Effects of roxarsone on performance, toxicity, tissue accumulation and residue of eggs and excreta in laying". Journal of the Science of Food and Agriculture. 74 (2): 229–236. doi:10.1002/(SICI)1097-0010(199706)74:2<229::AID-JSFA793>3.0.CO;2-F. R. L. Wershaw; J. R. Garbarino & M. R. Burkhardt (1999). Roxarsone in Natural Water Systems (PDF). Effects of Confined Animal Feeding Operations (CAFOs) on Hydrologic Resources and the Environment. Fort Collins, Colorado: U.S. Geological Survey. Retrieved 2020-06-06. KB Kerr; JR Narveson; FA Lux (1969). "Toxicity of an organic arsenical, 3-nitro-4-hydroxyphenylarsonic acid. Residues in chicken tissues". Journal of Agricultural and Food Chemistry. 17 (6): 1400. Bibcode:1969JAFC...17.1400K. doi:10.1021/jf60166a021.

External links No Arsenic In Pardoned Turkeys, But It Might Be In Yours at NPR

Illustrations

Worked examples

Example 1 — a first encounter with Roxarsone

Start with the simplest possible case. Write down what Roxarsone claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Roxarsone before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Roxarsone ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Roxarsone

In research: Roxarsone appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Roxarsone in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Roxarsone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antiprotozoal agents, Arsonic acids, Food safety, so understanding it makes those chapters shorter.
In everyday life: Look for Roxarsone outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Roxarsone in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Roxarsone means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Roxarsone out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Roxarsone in simple terms?

Why does Roxarsone matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Roxarsone?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Roxarsone.