Arsenic in Rice Linked to Chicken Litter

arsenic in rice
arsenic in rice

In 2016 epidemiologist Tamar Lasky, Ph.D., published Arsenic in chicken: a tale of data and policy in the Journal of Epidemiology & Community Health.

It’s a fascinating look at the links between factory-farmed chickens, arsenic-lace antibiotics, and the “arsenic in rice” story I’ve been covering this week.

While working in the U.S. Department of Agriculture in 2000, Tamar had a biostatistics student ask her to recommend a Master’s Degree topic.

She directed him to a National Residue Program (NRP) database of lab results measuring chemical residues in meat and poultry samples.

His statistical analysis of the database quickly revealed an anomaly. Chicken-sample arsenic levels measured more than three times higher than those in other meats.

Startled by the finding, he turned to veterinarians for a possible explanation. It wasn’t long before he had his answer; chicken feed routinely contained one of four arsenic-laced antibiotics:

  • roxarsone

    The arsenic in roxarsone-laced chicken feed passed from chicken litter into the soil, groundwater, streams and crops.
  • nitarsone
  • arsanilic acid


or carbarsone.

Chicken producers used these drugs to enhance growth, prevent disease and parasites, and give the chicken meat a more appealing pink color. The antibiotics also stopped coccidiosis, a parasite-related disease leading to intestinal damage.

The FDA approved roxarsone back in 1944 when farmers began relying on drugs to boost the agricultural industry’s growth. At the time, nobody gave much thought to the potential environmental and health consequences of their decision.

The Price of 56 Years of Arsenic-Based Antibiotic Use

 Fast-forward to 2021, and we’re living with those consequences.

Overcrowded chicken houses are breeding grounds for disease and parasites.

Thanks to Concentrated Animal Feeding Operations (CAFOs), individual chicken farmers eventually turned out over 125,000 broiler chickens every 12 weeks. They packed 20 to 30 thousand birds into windowless barns, where parasites rapidly migrated from chicken to chicken through feces.

So the farmers used even more arsenic-based drugs to keep the hungry parasites at bay – with little thought about the danger to consumers. Some farmers thought the organic arsenic they used was okay, not realizing it turned into inorganic arsenic before reaching end users. 

But where were U.S. studies testing the safety of their choices? Even when the European Union finally banned roxarsone in 1999, the FDA and USDA remained silent on the issue.

Not until 2002 did the truth emerge after Tamar directed her biostat student to study the database. Over the previous 56 years, untold billions of chickens had ingested arsenic-laden drugs.

And the people who ate them had unknowingly been eating the traces of inorganic arsenic. But the contamination spread far beyond that. 

Chickens also store arsenic in their feathers, which Big Ag grinds into meal for fertilizer. However, most of what they ingested passed through their digestive tracts as arsenic-poisoned chicken “litter” – an even more popular fertilizer.

When the arsenic from the litter entered the soil, it also leached into our groundwater and streams. And eventually, we were eating arsenic in rice as well as chicken.

Connecting Arsenic In Chicken Litter with Arsenic in Rice

But in 2000, the chicken-feed and arsenic in rice issue was only acknowledged by a student working on his Master’s degree. Not until January of 2004 did a scientific journal publish the first hint of a connection between the arsenic in chicken litter and the arsenic in rice.

Tamar co-authored the article, which observes:

“The mean concentration of total arsenic in young chickens was 0.39 ppm [parts-per-million]…”

This equates to 390 parts-per-billion – an astounding number when the maximum arsenic level for 1 cup of drinking water is 10 parts-per-billion. (In New Jersey, it’s half that).

The article also states that people who ate 2 ounces (60 grams) of cooked chicken received from .38 to 5.24 mcg of inorganic arsenic. Those eating about 12 ounces (350 grams) received over 30 mcg!

More importantly, for the long-term, “Roxarsone contains organic arsenic… Most of the excreted arsenic (found in litter) remains…”

Big Ag Slowly Starts Listening 

At least one Big Ag company got the message. Shortly after the article’s publication, Tyson Foods took arsenic off their chickens’ menu. Apparently, they found using one of the world’s most infamous poisons as a parasite killer, bird fattener, and meat dye isn’t necessary.

However, other broiler producers didn’t seem to care – even as additional studies reflected the problem.

  • In 2006, a Dartmouth College Department of Earth Sciences and Chemistry study focused on the danger on fertilizing cropland with arsenic-contaminated poultry litter.
  • In 2007, this effort from Duquesne University’s Departments of Biology, Chemistry, and Biochemistry warned that the arsenic “…can be readily leached into groundwater.”

Four years later, in 2011, Pfizer stopped selling roxarsone. But by then, Big Ag was feeding chickens an estimated 2 million pounds of roxarsone-laced feed every year. 

The damage was already done! According to the Food and Water Watch 2010 bulletin Poison-Free Poultry in Maryland, the arsenic in 2 million pounds of feed was enough to poison between 26 and 51 billion pounds of chicken litter.

The USDA recommends applying up to 6 tons of poultry litter per acre of crop. Jason Simmons, ARS-USDA

Approximately 90 percent of it, they reported, had been “… applied to cropland as fertilizer, and chicken litter converts to the much more toxic inorganic arsenic in as little as a week.”  

In 2013, nine food-safety groups sued the FDA to force their response to the situation. That same year, other antibiotic producers voluntarily withdrew their arsenic-enhanced products.

The FDA Faces the Problem: Too Little, Too Late

Finally, on December 31, 2015, the FDA withdrew approval for all U.S.-sold, arsenic-based drugs used in animal feed. Chicken litter no longer contains the poison, but the arsenic in rice will be with us indefinitely.

The massive amount of organic arsenic in that poison chicken litter is undeniably moving from the soil and water to become the arsenic in rice and our other food crops. 

In 2017, Dr. Greger informed us that we can’t escape it:

 “So, if you test the urine of … of Americans who don’t eat rice at all, they’re still peeing out about eight micrograms of toxic, carcinogenic arsenic a day… there’s a little bit in nearly all foods. But, eat a cup or more of white rice a day, and your exposure shoots up 65%.”

The best we can do is reducing our exposure to the most heavily contaminated foods, like rice. But without Tamar Lasky’s efforts, we might still be in the dark about where the arsenic in rice came from.

Arsenic may no longer be fed to chickens in the US, but the challenge is far from over. Tamar completes her paper with a sober assessment of a much larger problem,

“Arsenic in chicken is part of the larger issues around exposure to toxic chemicals, the use of antibiotics in food production and the wider issues around antibiotic resistance.”

She deserves our eternal gratitude for bringing the “arsenic in chickens” issue to public attention. Through the seemingly small act of pointing a student to a database, she unleashed an unprecedented environmental and public health win!

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