ScienceDaily reports that large quantities of antibiotic-resistant bacteria enter the environment via municipal – and especially hospital – wastewater streams. Although wastewater treatment plants reduce the total number of bacteria, the most hazardous multiresistant strains appear to withstand or even to be promoted by treatment processes. This was demonstrated by Eawag researchers in a study carried out in Lake Geneva, near Lausanne.

This news creates an additional driver for additional and urgent research, and more definitive action on the environmental impact of all pharmaceuticals, not just antibiotics, in wastewater and in the wider environment.

Studies such as this help identify the scale and wider impact of the problem, and identify the limited efficacy of traditional wastewater treatment systems developed by the Victorians who never, of course, perceived a problem from pharmaceutical residues in wastewater. Perhaps the majority of those antibiotic-resistant bacteria originate from hospitals, or from livestock, though the persistent driver of pharmaceuticals in wastewater enter in a more diffuse pattern.

The particular value of this work is the emphasis it will place on more appropriately directed transitional research, and more appropriate regulation, that should be targeted on emission hotspots such as hospitals and on the inadequacies of existing wastewater treatments. As we have discussed previously on the Clinical Waste Discussion Forum, the bulk of pharmaceutical discharges are diffuse, originating from excretion of the administered dose by the millions of pill-popping patients up and down the land and by our farm animals.

see also http://www.eawag.ch/medien/bulletin/20120322/index_EN