Fig. 2.

Percentage of antibiotic remaining in supernatants after 24 h of incubation in soil slurry as measured by HPLC-UV. ANOVA indicated significant differences between soil type and antibiotic type and for the interaction between soil and antibiotic (P < 0.0001). Letters indicate within-drug soil differences (Tukey-Kramer multiple-comparisons test, P < 0.001). Sulfadiazine and sulfadimethoxine were excluded from the analysis because of complications with solubility. Neomycin was excluded because we did not have a suitable protocol for quantification by HPLC-UV. Amp, ampicillin; Cep, cephalothin; Fox, cefoxitin; Cef, ceftiofur; Flo, florfenicol; Cip, ciprofloxacin; and Tet, tetracycline.