Transcript Leaching of a Veterinary Antibiotic Through Soil Columns

Leaching of a Veterinary Antibiotic
through Soil Columns
Lidia Esteve, Graduate Research Assistant
Amy Kaleita, Assistant Professor
Matthew Helmers, Assistant Professor
Iowa State University
PATHWAYS OF ANTIBIOTIC MOVEMENT INTO THE
ENVIRONMENT
Sources and transport of pharmaceuticals in the environment
Source: Heberer
(2002), toxicology
letters, 131, 5-17
ANTIBIOTICS IN THE ENVIRONMENT

Manure from treated livestock is the most relevant source of
veterinary antibiotic (Osenga, 2001).

The major use of antibiotics in agriculture is as animal growth
promoters (Levy, 1992).

Scope of problem: USGS survey (2000).139 streams in 30 States
were anayzed for 31 antibitotics. 17 antibiotics found at
concentration 1.7 ppm (erythromycin)– 0.03 ppm (ciprofloxacin)

Processes affecting antibiotic behavior and persistence:


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
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Photodegradation
Sorption
Aerobic conditions
Abiotic hydrolisis
Biodegradation
Volatilization
PROBLEM STATEMENT

Risks
 Disturbance to environmental bacterial community
 Development of bacteria resistance
 Toxicity in plants

Objectives of this study
 Study of the leach of tylosin in manure
 Get some preliminary data to understand the issue
MATERIALS AND METHODOLOGY

4 representative soils of Iowa :
 Canisteo silty clay loam (507)
 Clarion loam (138)
 Sparta loamy fine sand (41)
 Webster silty clay loam (107)

Sigma® tylosin tartrate
( 50mg/kg manure)

Swine Slurry manure (100ml/column)
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Indoor rainfall simulator (5cm/h intensity)

“Enzime Linked Inmuno Sorbent Assay” ( ELISA) methodology
RESULTS
6 mg tylosin + 100 ml slurry manure in each column
0.75
0.7
0.65
0.6
tylosin concentration (ng/ml)
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
Canisteo
Canisteo Blank
Clarion
Clarion Blank Dist. Water
sample
Sparta
Sparta Blank
Webster
Webster Blank tap w ater
RESULTS
60 mg+ 100 ml slurry manure in each column
0.9
tylosin concentration (ng/ml)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
Canisteo
Canisteo blank
samples
Sparta
Sparta blank
CONCLUSIONS

No significant concentration of tylosin (lower than 0.5 ng/ml) was
found in the leachate from any kind of soil at neither 6mg tylosin/
column nor 60 mg tylosin/ column

Tylosin likely remains in soil at our treatment concentrations, bound
to the organic matter, clay or manure
 Those results are in agreement with a recent Colorado University
study (October 2004) where it was found that the antibiotic
concentrations in river sediments are 20-1000 times higher than
concentrations found in river water.
CONCLUSIONS

Concentrations found in tap water and distilled water suggest that :
 There may be tylosin in tap water currently
 There may be interactions with any compound in tap water

The results in antibiotic detection show the need of more sensitive
and reliable methodologies for antibiotic trace concentrations.
Because ELISA methodology has shown in our study to be a screen
method, HPLC methodology would be required for validation of the
results.
RECOMMENDATIONS AND SUGGESTIONS FOR
FUTURE STUDIES

Develop more analyses increasing the concentration of tylosin in
order to find possible differences of tylosin concentration in leachate
between different kind of soils
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Do extractions from soil with and without manure to determine what
proportion of tylosin is bound to sediment and to the manure.
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More studies about the environmental repercussions of antibiotic
accumulation in sediments are required.