Table 2.

Antibiotic concentrations (mg/mL± SE; n = 4 water bottles) during experiment 1

	Tap water		Acidified water		Hyperchlorinated water
	Day 0	Day 7	Day 0	Day 7	Day 0	Day 7
Enrofloxacin	0.239 ± 0.006	0.237 ± 0.006	0.250 ± 0.004	0.248 ± 0.005	0.246 ± 0.002	0.155 ± 0.019
Doxycycline
Pharmaceutical grade	0.017 ± 0.001	0.017 ± 0.003	0.048 ± 0.001	0.043 ± 0.001	not tested	not tested
Chemical grade	0.052 ± 0.004	0.032 ± 0.001	0.037 ± 0.002	0.042 ± 0.002	not tested	not tested