Lidia Esteve, Graduate Research Assistant

Amy Kaleita, Assistant ProfessorMatthew Helmers, Assistant Professor

Iowa State University

Leaching of a Veterinary Antibiotic through Soil Columns

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: 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)

Indoor rainfall simulator (5cm/h intensity)

“Enzime Linked Inmuno Sorbent Assay” ( ELISA) methodology

RESULTSty

losi

n co

ncen

trat

ion

(ng/

ml)

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65

0.7

0.75

Canisteo Canisteo Blank Clarion Clarion Blank Dist. Water Sparta Sparta Blank Webster Webster Blank tap water

sample

6 mg tylosin + 100 ml slurry manure in each column

RESULTSty

losin

concentr

atio

n (

ng/m

l)

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Canisteo Canisteo blank Sparta Sparta blank

samples

60 mg+ 100 ml slurry manure in each column

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.

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.

CONCLUSIONS

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

Do extractions from soil with and without manure to determine what proportion of tylosin is bound to sediment and to the manure.

More studies about the environmental repercussions of antibiotic accumulation in sediments are required.