[Pharmwaste] Routine Feeding Of Antibiotics To Livestock May Be Contaminating The Environment

[DeBiasi,Deborah]

http://www.sciencedaily.com/releases/2007/07/070711134530.htm


Source: Soil Science Society of America 
Date: July 13, 2007 
More on: Agriculture and Food, Bacteria, Endangered Plants, Organic,
Microbes and More, Soil Types 

Routine Feeding Of Antibiotics To Livestock May Be Contaminating The
Environment

Science Daily - It is estimated that between 9 and 13 million kilograms
of antibiotics are used annually in the United States for raising
livestock, with the majority being used for growth advancement and
disease prevention purposes. Large amounts of antibiotics fed to
livestock are excreted and end up in animal manure, which is commonly
applied to agricultural land to provide crop nutrients. Therefore, food
crops grown on manure-altered soils are exposed to antibiotics.

Large amounts of antibiotics fed to livestock are excreted and end up in
animal manure, which is commonly applied to agricultural land to provide
crop nutrients. 

Scientists at the University of Minnesota have been evaluating the
impact of antibiotic feeding in livestock production on the environment.
This particular study, funded by the United States Department of
Agriculture (USDA), evaluated whether food crops accumulate antibiotics
from soils spread with manure that contains antibiotics.  

Plant uptake was evaluated in a greenhouse study involving three food
crops: corn, lettuce, and potato. Plants were grown on soil modified
with liquid hog manure containing Sulfamethazine, a commonly used
veterinary antibiotic. This antibiotic was taken up by all three crops.
Concentrations of antibiotics were found in the plant leaves.
Concentrations in plant tissue also increased as the amount of
antibiotics present in the manure increased. It also diffused into
potato tubers, which suggests that root crops, such as potatoes,
carrots, and radishes, that directly come in contact with soil may be
particularly vulnerable to antibiotic contamination. 

The ability of plants to absorb antibiotics raises the potential for
contamination of human food supply. However, Satish Gupta, group leader
notes "The adverse impacts of consuming plants that contain small
quantities of antibiotics are largely unknown". Consumption of
antibiotics in plants may cause allergic reactions in sensitive
populations, such as young children. There is also concern that
consuming antibiotics may lead to the development of antimicrobial
resistance, which can render antibiotics ineffective. 

Holly Dolliver, the lead scientist in this study, notes that antibiotics
consumed by plants may be of particular concern to the organic farming
industry. Manure is often the main source of crop nutrients for organic
food production, since regulations prohibit the use of synthetic
fertilizers. According to the USDA, producers must manage animal
materials in a manner that does not contribute to contamination of crops
by residues of prohibited substances, which includes antibiotics.
However, manures containing antibiotics are not formally banned or
prohibited. 

Further research is needed to investigate the presence of antibiotics in
edible parts of plants, especially vegetables that are consumed raw, and
how different plants absorb different antibiotic compounds. Research is
ongoing at the University of Minnesota to further investigate the
potential fate and transport of antibiotics introduced to the
environment from livestock operations. 

Results from the study are published in the July-August 2007 issue of
the Journal of Environmental Quality. The research was also presented in
Indianapolis, IN at the Annual Soil Science Society of America Meeting
in November 2006.

Note: This story has been adapted from a news release issued by Soil
Science Society of America.

Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
WEB site address:  www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
Mail:          P.O. Box 1105, Richmond, VA  23218 (NEW!)
Location:  629 E. Main Street, Richmond, VA  23219
PH:         804-698-4028
FAX:      804-698-4032