The following letter to the editor was submitted by the Center for a Livable Future to The Baltimore Sun following an article published in Sunday’s edition on Perdue’s efforts to recycle poultry litter. The article was also discussed in a blog post on B’MoreGreen yesterday.

We were disappointed to see that Timothy Wheeler left out any mention of an important environmental and human health consideration in his recent piece on the Perdue poultry manure pelletization plant (“Perdue manure recycling plant reduces nutrients in bay”).

According to estimates from Delmarva Poultry Industry, Inc., 88% of domestically produced broiler chickens are fed an arsenic-containing drug called roxarsone.  Some of the arsenic from this drug stays behind in the edible portions of the chicken, and the rest ends up in the poultry manure.

Numerous scientific and peer-reviewed research studies have measured heightened levels of arsenic in poultry manure, and research from the United States Geological Survey and other researchers has shown that the arsenic in poultry manure is rapidly converted into an inorganic form that is highly water soluble and capable of moving into surface and ground water.

Inorganic arsenic is recognized by the U.S. EPA as a carcinogen.  Earlier this year, the agency released a draft reassessment of arsenic toxicity, which indicates that the most recent evidence suggests that arsenic is 17 times more potent as a carcinogen than previously understood.  Arsenic exposures have also been linked to cardiovascular disease, diabetes, neurological deficits, and other health problems.

As reported in a peer-reviewed research article one of us published in the American Chemical Society’s Chemosphere journal in 2008, pelletized poultry manure also contains elevated levels of arsenic, showing that the pelletization process does not remove arsenic from poultry manure.

What is particularly upsetting about the marketing and sale of pelletized poultry manure is its labeling as “organic”, a term that conjures perceptions of safety.  The organic certification found on pelletized poultry manure fertilizer, which is different in meaning from the more commonly recognized USDA Organic label, does not ensure that the product has been found not to contain concerning levels of arsenic.  These concerns are heightened by the marketing of the product, which in some cases contains claims that the fertilizer is “safe for kids and pets,” and that, compared to chemical fertilizers, lawns fertilized with the product are safe for play immediately after application

Perdue’s pelletized output thus far barely puts a dent in the massive volumes of poultry manure polluting the Chesapeake Bay watershed.  Between 2001 and 2009, the states of Delaware, Maryland and Virginia produced 7.2 billion broiler chickens, each producing between 1.46 and 4.9 kilograms of manure.  A simple calculation tells us that the Delmarva broiler poultry industry produced between 10 and 35 billion kilograms (or 12 to 39 million tons) of poultry manure each year.  Given this, the 700,000 tons pelletized by Perdue account for between 2 and 6 percent of waste generated – an amount that can hardly be seen as a solution for Chesapeake Bay nutrient problems.

In sum, pelletization of poultry manure does little to rectify the nutrient problem in the Chesapeake Bay watershed and it creates new exposure pathways for people (especially children) who come into contact with the fertilizer-on lawns, gardens or golf courses-to be exposed to arsenic.

Keeve E. Nachman, PhD, MHS
Director, Farming for the Future Program
Johns Hopkins Center for a Livable Future
Johns Hopkins Bloomberg School of Public Health

Robert S. Lawrence, MD
Director, Johns Hopkins Center for a Livable Future
Professor of Environmental Health Sciences, Health Policy, and International Health
Johns Hopkins Bloomberg School of Public Health