Using Copper to Reduce Microbial Contamination in Drinking Water

In developing countries nearly 80% of all diseases are linked to water and sanitation issues (WHO & UNICEF, 2004); globally over two million people die annually from water-born diarrheal disease (WHO & UNICEF, 2000).  It has long been known that some metals can exhibit powerful anti-bacterial properties. Copper has been used for hundreds of years as a means to purify drinking water but only recently have scientists begun to elucidate the mode of action for copper induced microbial death.  In 2008 the U.S. Environmental Protection Agency officially registered copper alloys as biocidal agents. Now these alloys need to be studied to determine efficacy at different concentrations and with a variety of disease-causing microbes.  This study investigates the powerful bactericidal effects of copper as a low cost accessible method to purify drinking water of pathogenic waterborne microorganisms. More specifically, E. coli was used as a model organism to test the efficacy of solid copper at killing microorganisms in drinking water over variable amounts of time. Efficacy of cell death was assessed with viable plate counts. Results show that ≥48cm² of solid copper in 100 mL of water can kill E. coli (at an average concentration of 3.1x10⁵ CFU/mL) within 24 hours. Further research is needed to determine the optimal copper to water volume ratio as well as the precise timing of cell death. It is also essential that the copper ion concentrations remain below EPA limits of 1.3 mg/L; preliminary findings produced inconsistent values. The results of this research could be beneficial to those living in locations where safe potable water is not readily available, or for those travelling to remote or foreign locations as well as hikers and campers.