Antibiotics found in waterways pose a potential threat to aquatic ecosystems and possibly human health, according to research recently published in Elsevier's Marine Pollution Bulletin.
Concern with water quality is particularly relevant to today's observance of World Water Day, whose theme, "Water for Life", underscores the importance of improving the quality and health of water sources.
Antibiotics enter waterways through sewage systems, following consumption and excretion by both livestock and humans. The presence of antibiotics in the water supply is cause for concern because of their potential to contaminate water used for drinking, irrigation and recreation; accelerate widespread bacterial resistance, and negatively affect normal bacteria found in nature.
In "Ecosystem response to antibiotics entering the aquatic environment," the Australia-based research team of Simone D. Costanzo, John Murby and John Bates first looked at whether antibiotics were present in the drainage and environmental waters located downstream from a sewage treatment plant in Brisbane, Australia.
Not only were antibiotics present in both areas, but they were also detected in the receiving waters that entered the plant, as well as in a water source upstream from the plant.
The team then took bacterial samples from all of the separate water sources and tested these cultures for their resistance to six different antibiotics The cultures taken from the treatment plant itself displayed resistance to all six types of antibiotics tested, and the samples taken from the receiving waters that entered the plant showed resistance to two of the antibiotics.
While little attention has been given to these chemicals as pollutants, the research points to the risk associated with the transfer of resistant genes from harmless bacteria to pathogenic bacteria, and to how humans interact with the aquatic environment.
Scientists and ecologists are cautioned to become more aware of the necessity of assessing the natural capacity of organisms in the environment to break down these organic pollutants, as well as the potential damage these substances can cause to ecological systems and human health.