Soil Adsorption, Photodegradation, and Removal of Antibiotics from Water by Duckweed:

Case studies examining Erythromycin, Lincomycin, and Others

Abstract

For obtaining fundamental data about the fate of ampicillin （ABPC）, oxytetracycline （OTC）, erythromycin （EM）, and lincomycin （LCM） in water environments, distributions of resistant bacteria, soil adsorption, photodegradation, and removal by duckweed were studied. Against the total population of heterotrophic bacteria in a water sample from Lake Biwa, bacteria resistant to 50 ㎎/L ABPC, OTC, EM, and LCM were, respectively, 4.3, 1.9, 2.5, and 26％. During the soil adsorption test, ABPC and OTC at 10 ㎎/L decreased respectively to 81％ and 15％ in 2 days. Under sunlight, 1.0 ㎎/L OTC and EM decreased respectively to ＜0.5％ and 58％ in 5 days. The duckweed uptake test results showed that 0.1 ㎎/L ABPC and EM decreased respectively to 28％ and 21％ in 7 days. These results demonstrate that LCM was slightly adsorbed to soil, photodegraded, or removal by duckweed, indicating its persistence in water environments.