Influence of Adsorbed Antibiotics on Water Quality and Soil Microbes

Background/Need:
The use of antibiotics and growth hormones in human and veterinary medicine has had a significant effect on water quality. Many pharmaceutical compounds were even frequently detected in the treated effluent from many wastewater treatment plants located in different countries. Thus, the occurrence and biological impacts of pharmaceutically active compounds in the environment is becoming an emerging issue. Contradictory results have been reported on the antibacterial activity and bioavailability of antibiotics adsorbed on soils and sediments due to binding or complex formation. Furthermore, the mobility of ionizable antibiotics in soil environments has not been fully elucidated. Thus, there is an urgent need to investigate the fate and transport of antibiotics in soils and groundwater. In addition, the influence of adsorbed antibiotics on the
antimicrobial activity of bacteria needs to be fully studied, too.
Objectives:
The following objectives were focused during this period of study: (1) What are the adsorption and desorption kinetics of selected antibiotics onto or from the external surfaces of non-swelling clays and intercalated in the interlayer spaces of swelling clays? (2) How will desorption of antibiotics affect water quality? (3) What are the antimicrobial activities of the antibiotics adsorbed on external surfaces or intercalated into the interlayer spaces of clay minerals? (4) Will soil microbes develop resistance to the antibiotics adsorbed on external surfaces or intercalated into the interlayer spaces of clay minerals?