Vegetative buffer strips show limited effectiveness for reducing antibiotic transport in surface runoff

Area of Science:

• Environmental Science
• Agricultural Science
• Water Quality

Background:

• Vegetative buffer strips (VBS) are known to reduce sediment, nutrient, and herbicide runoff.
• Their efficacy in mitigating veterinary antibiotic (VA) loads in surface runoff remains under-documented.

Purpose of the Study:

• To evaluate the impact of VBS vegetation type and width on the reduction of sulfamethazine (SMZ) and lincomycin (LIN) loads in surface runoff.
• To compare the effectiveness of VBS for VA removal against their known performance for other agricultural contaminants.

Main Methods:

• A two-way factorial experiment using plots with varying vegetation (tall fescue, fescue-switchgrass hedge, native grass mix, fallow control) and widths (0, 2, 5, 9 m).
• Spiked turkey litter was applied to the source area, and runoff was simulated and collected.
• VA concentrations and loads in runoff were analyzed.

Main Results:

• VA loads at the 0-m sampler represented 3.8–5.9% of applied amounts.
• VA transport was predominantly in dissolved form (90% SMZ, 99% LIN).
• Only tall fescue significantly reduced SMZ and LIN loads (~30%); reductions were modest at field scales (7–16% for SBARs of 10:1–20:1).

Conclusions:

• Grass VBS are less effective for reducing veterinary antibiotic loads (SMZ, LIN) in surface runoff compared to sediment, nutrients, and herbicides.
• Vegetation type and width had a limited impact on VA load reduction in this study.
• Further research may be needed to optimize VBS design for veterinary antibiotic mitigation.