Sorption of Veterinary Antibiotics By Biochars Derived from Different Feedstocks.

Increasing environmental concentrations of antibiotics have raised serious concerns on the proliferation of antibiotic resistant bacteria. This increase has been linked to the widespread and imprudent use of veterinary antibiotics in animal feeding operations. After administration to animals, a large percentage of veterinary antibiotics are excreted into manure as parent compounds or bioactive metabolites and then enter the environment through manure land applications. Soil amendment with biochars may prove to be an innovative management strategy to manage the risk of veterinary antibiotics through sorption. Therefore, this study aims to investigate sorption of lincomycin, one commonly used veterinary antibiotic, by 31 biochars produced from different feedstock biomass (plant waste and animal manure) and at a range of pyrolysis temperature (300 to 600 ^oC) to better understand the potential of biochar application. Two-day Sorption experiments were examined in detail using the batch method at pH around 6 and 9. Results indicate that sorption of lincomycin by biochar is significantly affected by feedstock type and pyrolysis temperature of biochars. The lincomycin sorption capacity of plant-waste-derived biochars (n =15) was 403 ± 257 μg g^-1 at pH around 6 and 151± 110 μg g^-1 at pH around 9, and that of animal-manure-derived biochars (n =16) was 248 ± 166 μg g^-1 at pH around 6 and 164± 88 μg g^-1 at pH around 9. These results show that biochars have the potential as a sequestration agent for veterinary antibiotics. The addition of biochars to soils can be an in-situ remediation strategy for antibiotics-contaminated soil and water by decreasing the antibiotic transport and bioavailability.