Sludge Watch ==> Plants Uptake Antibiotics

[Maureen Reilly]

Sludgewatch Admin:

Land applied sewage sludge and livestock manure contaminated with 
antibiotics are the issue.
Sewage sludge contains antibiotics excreted to toilets, from staledated 
medications disposed into the toilet (the required disposal technique for 
many hospitals and nursing homes), and from wastewater from pharmacuetical 
labs and manufacturers into the sewers.

Many livestock are routinely dosed with antibiotics as a growth promoter and 
infection prevention measure in intensive livestock operations.

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Plants uptake antibiotics
12.jul.07
EurekAlert

MADISON, WI -- 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.

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.

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.