| What is roxarsone and why should we be concerned about its use? Roxarsone is an arsenical antimicrobial drug used extensively in poultry and swine production to combat intestinal parasites, speed growth and improve pigmentation. Some large poultry integrators have reported voluntarily withdrawing roxarsone from feed regimens, although I am unaware of efforts to validate these claims. Further, I am unaware of similar voluntary withdrawals from swine producers. Federal agencies do not mandate the reporting of food animal drug usage, making it difficult to characterize the use of the drug in food animal production.
From a public health perspective, it is increasingly apparent that today, while humans are exposed to arsenic through a variety of pathways, none are as easily controllable as this one. Recent research points to the long-term impacts of the use of arsenic in our food system:
* Some of the administered arsenic stays behind in poultry muscle tissue in inorganic form - evidence of this has been published by Tamar Lasky (USDA) and David Wallinga (IATP).
* Much of the administered arsenic ends up in poultry waste - most as unmetabolized roxarsone, some as various inorganic and organic arsenic species (Garbarino/USGS).
* Excreted roxarsone is rapidly degraded in the environment into arsenate and arsenite, both inorganic forms of arsenic (Garbarino/USGS).
* Management of food animal waste primarily through land application, but also as pelletized fertilizer (Nachman 2008) for residential and commercial settings, incineration (Nachman 2005), and "recycling" of poultry waste into feed (Sapkota) creates the potential for arsenic to move from agricultural fields into nearby surface and ground water sources, fostering opportunities for humans to be exposed to inorganic arsenic (Nachman 2005, Silbergeld and Nachman 2008).
Human exposures to arsenic and roxarsone are of public health concern. The Environmental Protection Agency classifies arsenic as a Class A human carcinogen, and chronic exposures to arsenic have been convincingly linked to cardiovascular disease, diabetes, neuropathy, and neurocognitive deficits in children. In addition, emerging scientific research on these and other health effects resulting from chronic low-level exposures to arsenic, has prompted EPA to reassess its assessment for arsenic to ensure it is adequately protective of human health.
Given this and numerous other troublesome environmental and human health consequences stemming from industrial food production methods, I commend Rep. Israel on the introduction of this important piece of legislation.
Keeve E. Nachman, PhD, MHS is Science Director for Food Production, Health and Environment at the Johns Hopkins Center for a Livable Future (CLF) located at the Johns Hopkins Bloomberg School of Public Health (JHSPH). His research focuses on determining the environmental, public health and social consequences of industrial food animal production and animal waste management. |
