Inorganic Arsenic Found in Chickens Treated With Drug 3-Nitro

Silver Spring, MD (TFC) – An approved animal drug known as 3-Nitro® (roxarsone) was added to chicken feed prior to July 2011. This drug was known to contain an organic form of arsenic, which is known to be toxic, but indeed it is less toxic than inorganic arsenic. In 2011, the Food and Drug Administration admitted that roxarsone contained inorganic arsenic, which is a much more toxic compound. After discovering this, the FDA’s Center for Veterinary Medicine and the Center for Food Safety and Applied Nutrition developed a new analytical method used to detect minute levels of arsenic in animal tissue.

It is important to note that organic arsenic is in the environment as a naturally occurring substance and can also be a contaminant in water, air, soil and various food products. In this case, the cause for concern is the organic arsenic found in 3-Nitro® that could transform into inorganic arsenic found in the chicken feed at high levels.

The FDA made a statement in the Product Safety Information section on their website about Arsenic from 3-Nitro®/Roxarsone in Poultry:


Using the new method, FDA scientists found that the levels of inorganic arsenic in the livers of chickens treated with 3-Nitro® were increased relative to levels in the livers of the untreated control chickens.

Alpharma, a subsidiary of Pfizer, Inc., decided to voluntarily suspend sale of 3-Nitro® and to facilitate an orderly process for suspending use of the product in the United States. Ownership of the veterinary drug subsequently changed to Zoetis, Inc., who continued the suspension from sale of 3- Nitro®. On February 27, 2014, Zoetis, Inc. voluntarily withdrew the new animal drug application for 3- Nitro®. On the same day, Zoetis, Inc. and Huvepharma AD voluntarily withdrew all new animal drug approvals and supplements for 3- Nitro®, as well as arsenilic acid, and carbasone (two other arsenical new animal drugs) for use in animal feed (including all combinations with other approved new animal drugs).
Source: FDA


There is a rumor invading the internet claiming that 70% of chicken in the United States contains arsenic, but this is actually an unfounded claim. The amount of poultry found with inorganic arsenic may be much higher or lower depending on which farms have added 3-Nitro® to the bird feed. Many people could have suffered from heavy toxicity after eating the meat of chickens treated with this drug. Now, although Alpharma has suspended the use of 3-Nitro®, this may not be the end of this story, as drug companies may attempt to reintroduce these drugs under new names.
In a study published in early 2011 by JC Kawalek entitled, “Data on various arsenic species present in broilers treated with roxarsone,” it was stated that inorganic arsenic found in much higher amounts (156 μg/kg) than the allowable levels (10 μg/kg)  were found in medicated chicken feed.


Hence the contribution of the pre-mix to the medicated feed is approximately 3- 4 μg/kg inorganic arsenic (As (III) and As (V)). The mass balance for arsenic was not met for the control feed. Our speciation data for As (III) and As (V) only account for 56 μg/kg inorganic arsenic whereas the total arsenic measured by our analysis was 156 μg/kg, meaning that the speciation only accounted for ~30% of the total.

Control and roxarsone-medicated chicken feed have detectable levels of inorganic arsenic that are higher than the allowed contamination levels of the roxarsone API. In addition the roxarsone medicated premixes contained several unknown arsenical species…. Roxarsone and its metabolites were present in liver tissues from chicks fed roxarsone-medicated feed. The incurred levels of inorganic arsenic species were highly variable in treated chicks but appeared to be significantly greater than that in the untreated control birds.
Source: Division of Animal Research/FDA


This analysis tells us that of the total 156 μg/kg arsenic measured, approximately 36% (56 μg/kg) inorganic arsenic was measured. Chicks treated with roxarsone had much higher levels of inorganic arsenic, but the levels were not uniform, so contamination may play a role.
It is important to understand that our food may contain toxic compounds. We must be very careful deciding what we eat, especially what is found on the shelves in your average grocery store. Meat may be the most risky food due to the animal feed and medications added to the diets of farm animals. It is important that we limit toxicity in our bodies, even if it means to limit foods in our diet from which we would otherwise derive substantial nutrition. Reading the labels and knowing ingredients to foods is important, but not all information will be listed.
No nutrition label lists the amount of arsenic or any other toxic chemical found in a certain food, and for this reason, we must always be skeptical of the levels, even minute levels, of toxic ingredients within our diet.

Chickens Image Source: M C Morgan, Flickr, Creative Commons

Image Source: M C Morgan, Flickr, Creative Commons