Seeking a Holistic Assessment

My last post, Arsenic and Rice, summarized the recent controversy regarding arsenic levels in rice and linked to the primary sources.  I ended the post by commenting that it was my hope that would use this issue as impetus to "demand a more holistic assessment of agricultural production methods - an assessment that takes into account the full spectrum of considerations and not just product-specific economic justifications."  This post explains what I meant.

While much of the press this week has focused on the concerns that a consumer may have about arsenic residues in food, what intrigues me most about this story is how we got here.

The Arsenic Facts website produced by the rice industry correctly notes that some arsenic is naturally occurring in the air, soil, and water.  Consumer Reports responds, however, that the federal Agency for Toxic Substances and Disease Registry considers human use of arsenic-based products to be the largest source of arsenic contamination in the U.S. today.

The U.S. is the world’s leading user of arsenic, and since 1910 about 1.6 million tons have been used for agricultural and industrial purposes, about half of it only since the mid-1960s. Residues from the decades of use of lead-arsenate insecticides linger in agricultural soil today, even though their use was banned in the 1980s. Other arsenical ingredients in animal feed to prevent disease and promote growth are still permitted. Moreover, fertilizer made from poultry waste can contaminate crops with inorganic arsenic.

It appears that the south-central states are still dealing with the consequences of the toxic pesticides (some arsenical) applied to the soil in efforts to eradicate the boll weevil. This should be a reminder to us that what we do to our soil, and more generally to the environment, can and often does have an impact far into the future. What may be profitable or expedient in the short run may not be either when considered more broadly.

More recently, however, a less direct soil contaminant has been linked to the arsenic problem - poultry litter. And, this issue once again questions the true "cost" of producing cheap food.

It was only last year -  in June 2011,  that the FDA announced that drug manufacturer Pfizer would "voluntarily suspend" the sale of the arsenical animal drug 3-Nitro® (Roxarsone).  Roxarsone has been commonly used in poultry production for many years and is also approved for use in pigs. The suspension was based on FDA testing that found levels of inorganic arsenic in the livers of chickens who were given Roxarsone. The FDA prepared a Question and Answer webpage that explained the test results and reassured consumers about the safety of chicken products. The FDA defended its prior approval of Roxarsone in livestock production, stating that its tests had indicated that it would not be converted from an organic to inorganic (more dangerous) form of arsenic.  The FDA stated that while Roxarsone has been used most, three other arsenic drugs are approved for use -  nitarsone, arsanilic acid, and carbarsone.

However, a review of scientific literature indicates that others have been concerned about the use of arsenic-based animal drugs for years.  Their use has been banned in the European Union since the late 1990's.  It has been reported that Tyson Foods, stopped using arsenic based drugs in July 2004 after negative publicity about roxarsone's use.  Perdue says it doesn't use it any longer, and McDonald's says its suppliers don't either.  But what about the rest of the industry?  Why was FDA so late in acting;  why only a manufacturer's suspension; why allow other replacement arsenic-based drugs?

Arsenic: A Roadblock to Potential Animal Waste Management Solutions, published in 2005 documents some of the longstanding research identifying arsenic in poultry production as a problem -

Arsenic in [poultry] waste results from the use of arsenicals added to poultry feed for growth promotion and prevention of parasitic infections. The U.S. Geological Survey has calculated, based on arsenic concentrations measured in poultry waste, that between 250,000 and 350,000 kg arsenic is annually applied to land in the United States (Rutherford et al. 2003). Although roxarsone, the predominant arsenical added to poultry feed, is an organoarsenical, there is strong evidence that the drug is converted into inorganic arsenic within the chicken (Arai et al. 2003) and is also rapidly transformed into inorganic arsenic in wastes and soils (Garbarino et al. 2003). Elevations in soil arsenic levels have been reported in fields where poultry wastes have been applied (Gupta and Charles 1999). This form of arsenic is readily leachable and may therefore move into groundwater (Rutherford et al. 2003).

Keeve E. Nachman, Jay P. Graham, Lance B. Price, and Ellen K. Silbergeld, Arsenic: A Roadblock to Potential Animal Waste Management Solutions, Environ Health Perspect. 2005 September; 113(9): 1123–1124.

USDA ARS funded studies have confirmed the problem. Arsenic in Field Runoff Linked to Poultry Litter  - "fields amended with poultry litter can accumulate significant levels of arsenic."

We have known for some time that plants can absorb arsenic from the soil and that rice is particularly susceptible. This is not a new issue.

Yet, we continue to have FDA approved arsenic-based animal drugs available for use in livestock production. Recognizing the problem, last June, Maryland became the first state to ban the use of arsenic in poultry feed. The law goes into effect January 1.

While Consumer Reports asks the FDA to set limits for arsenic levels in rice, I make an additional request and call upon Congress to revisit the animal drug approval process. While the FDA should undertake this reconsideration itself, it is likely that it does not have the resources, the political clout, or the requisite legal authority to undertake the kind of systemic approach that is needed to develop more sustainable production practices. We need to stop looking at ways to produce an individual crop or animal in the cheapest way possible and look holistically at our overall food system.

And, speaking of a holistic analysis, while Pfizer agreed to suspend the sale of Roxarsone in the U.S., it indicated that it would continue to manufacture and export Roxarsone overseas.  Do we really want to encourage arsenic contamination in other countries?  Particularly in a global marketplace, that doesn't seem to make much sense.