Detection

This thesis focuses on the environmental effects of the macrolide antibiotic erythromycin from livestock production practices and its possible influence in aquatic ecosystems.

The veterinary antibiotic, erythromycin, is used for disease prevention and growth promotion in livestock.

Erythromycin has been frequently detected in streams and sediments in the U.S.

The widespread use of veterinary antibiotics in agriculture has led to increased concern about their environmental fate.

For this research, a microcosm system was utilized to monitor the fate (including movement, binding, and degradation) along with bioavailability of the compound to aquatic invertebrates.

The bioavailability study included the development of a surrogate model using a passive sampling device to assess erythromycin in aquatic systems with and without sediment.

Analytical procedures to detect erythromycin in water and sediment were improved to assist in quantification.

Results from the environmental fate study indicate that erythromycin has an affinity to bind to particulate matter and sediment and is influenced by biotic processes especially mineralization.

An aged sediment microcosm system was incubated with erythromycin for 0, 1, 3, and 8 weeks which demonstrated its ability to be sequestered, but addition of surface water columns to the aged residues influenced the mobility of erythromycin into water and from extractable sediment residues.

Erythromycin has been shown to be less bioavailable to aquatic organisms, compared to sulfamethazine, but additional studies with sediment containing a manure amendment could possibly influence its ability to affect non-target organisms through exposure and uptake.