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[SANET-MG] arsenic in animal waste managment
July 8, 2005
Prof. Joe Cummins
Arsenic in animal waste management
The abstracts of two publications are given below. The first
publication deals with the problems of waste management in the face of
arsenical pharmaceuticals in animal feed. The second article describes a
common arsenical used to treat chickens for parasites. Arsenic is known
to be a human carcinogen, even at very low level in the water supply or
diet. The problem facing organic farmers is knowing their compost
source, I believe. However, I would appreciate comments on animal waste,
arsenic and compost in organic farming.
Arsenic—a roadblock to potential animal waste management solutions
Keeve E. Nachman, Jay P. Graham, Lance B. Price,and Ellen K. Silbergeld
doi:10.1289/ehp.7834 (available at http://dx.doi.org/)
The localization and intensification of the poultry industry over the
past 50 years has
incidentally created a largely ignored environmental management crisis.
As a result of
these changes in poultry production, concentrated animal feeding
operations produce far
more waste than can be managed by land disposal within the regions they
As a result, alternative waste management practices are currently being
including incineration and pelletization of waste. However, organic
arsenicals used in
poultry feed are converted to inorganic arsenicals in poultry waste,
limiting the feasibility of waste management alternatives. The presence
of inorganic arsenic in incinerator ash and pelletized waste sold as
fertilizer creates opportunities for population exposures that did not
previously exist. The removal of arsenic from animal feed is a critical
step towards safe poultry waste management.
Environ. Sci. Technol., 37 (8), 1509 -1514, 2003. 10.1021/es026219q
Environmental Fate of Roxarsone in Poultry Litter. I. Degradation of
Roxarsone during Composting
J. R. Garbarino,* A. J. Bednar, D. W. Rutherford, R. S. Beyer, and R. L.
Roxarsone, 3-nitro-4-hydroxyphenylarsonic acid, is an organoarsenic
compound that is used extensively in the feed of broiler poultry to
control coccidial intestinal parasites, improve feed efficiency, and
promote rapid growth. Nearly all the roxarsone in the feed is excreted
unchanged in the manure. Poultry litter composed of the manure and
bedding material has a high nutrient content and is used routinely as a
fertilizer on cropland and pasture. Investigations were conducted to
determine the fate of poultry-litter roxarsone in the environment.
Experiments indicated that roxarsone was stable in fresh dried litter;
the primary arsenic species extracted with water from dried litter was
roxarsone. However, when water was added to litter at about 50 wt % and
the mixture was allowed to compost at 40 C, the speciation of arsenic
shifted from roxarsone to primarily arsenate in about 30 days.
Increasing the amount of water increased the rate of degradation.
Experiments also suggested that the degradation process most likely was
biotic in nature. The rate of degradation was directly proportional to
the incubation temperature; heat sterilization eliminated the
degradation. Biotic degradation also was supported by results from
enterobacteriaceae growth media that were inoculated with litter slurry
to enhance the biotic processes and to reduce the concomitant abiotic
effects from the complex litter solution. Samples collected from a
variety of litter windrows in Arkansas, Oklahoma, and Maryland also
showed that roxarsone originally present had been converted to arsenate.
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