Copper and silver vessels are age-old bacteria killers

Household drinking water and coliforms (Source: Wikimedia Commons)
Household drinking water and coliforms (Source: Wikimedia Commons)

About 3 million children from developing countries below the age of 5 die every year due to diarrhoeal diseases caused by polluted water, poor sanitation and faecal contamination of drinking water sources. The paper titled 'Effect of storage containers on coliforms in household drinking water' published in the International Journal of Current Microbiology and Applied Sciences, informs that methods used to detect the coliforms present in water polluted with human and animal faeces which contain highly pathogenic coliform microorganisms, are relatively simple and economical.

In developing countries where people collect drinking water from surface water sources like ponds, wells, streams, municipal pipes, tanks and then store it at their homes for hours or sometimes days, water can become contaminated at any point in this process. This increases the possibility of faecal contamination of water inside the household. Contamination can occur during the handling of water like drawing of water from storage vessels with wide openings, placing contaminated hands in the vessels, cups and dippers etc. Thus, effective, affordable, functional and sustainable intervention strategies are required to prevent the contamination of water stored at home.

The study

The paper presents the findings of a study that evaluated the effect that different kinds of vessels used for storing water had on the presence of coliforms, over different periods of time. The water samples were obtained from a borewell located near stagnated sewage water at Madippakam, Chennai. Storage containers made of glass, plastic, ceramic, stainless steel, aluminum, mud pots, coconut shells, brass, copper and silver were used, and the water samples were analysed for the presence of coliforms before and after storage at different time intervals from 0 to 24 hrs.

The findings

  • Water stored in mud, silver, brass and copper containers showed a significant reduction in coliform bacteria.
  • However, water stored in other containers such as glass, plastic, ceramic, coconut shells did not show reduction in coliform bacteria.

The paper informs that evidence from other studies also shows that metals such as copper and silver have been traditionally used to store water in Indian homes and have been found to be most effective in eliminating coliform bacteria from stored water. This study argues for the need to promote the use of water storage containers/ vessels made of oligodynamic metals such as copper and brass to control faecal coliforms in drinking water. While silver is effective too, it is also very expensive. The paper ends by suggesting the need for future studies to elaborate the mechanism of interaction between silver, copper and brass containers.