Resource 3

The quality of drinking water ¹

Down through history the desire for drinking water that looked and tasted good has led to the construction of private rainwater collectors, reservoirs and extensive systems of pipes, canals and aqueducts.

However, the contaminants that caused illness and death were not so easily removed and these elaborate systems sometimes resulted in even greater problems. Many historians, for example, believe that the fall of the Roman Empire was aided by lead poisoning, brought about by high levels of the metal leaching into the drinking water as it was carried to Rome from distant reservoirs in pipes lined with lead.

Until Anton van Leeuwenhoek saw micro-organisms in a drop of water, the idea that water contained a world of microscopic organisms was unknown. Even after Leeuwenhoek's work was published in 1684, the world at large remained unconvinced that water was anything other than a pure substance.

The 1854 cholera epidemic

In 1854, many Londoners living in the vicinity of Broad Street began to develop symptoms of the much-dreaded disease, cholera. The sudden onset of watery diarrhoea, with sufferers losing as much as 20 litres of water a day, led to rapid dehydration and death of 70% of the victims.

Although the cause of cholera was as yet unknown, John Snow (1813-1858), a physician and epidemiologist, had 5 years earlier established that the disease was spread from one infected person to another in contaminated food and drinking water. Snow believed that the source of the local outbreak was the public hand-operated water pump in Broad Street which, he inferred, had been contaminated with raw sewage.

Unable to convince the local authorities that the pump should be closed to the public, Snow set out and stole the pump's handle. Within days the number of deaths from cholera dropped from hundreds to only a few. He made the public aware that contaminated drinking water was a health risk and changes to the way water was supplied were initiated.

Drinking water quality

The protection of public health is the primary aim of water-supply bodies around the world. This aim is a reflection of the changes proposed by John Snow over 130 years ago. Not only must drinking water look good, with little taste or odour, it must also, if possible, be free of pathogens (disease-causing micro-organisms) as well as any inorganic or organic contaminants that pose a risk to public health.

In 1984 and 1985, the World Health Organisation (WHO) released its Guidelines for Drinking-Water Quality. This publication has become the basis for drinking water standards around the world. In Australia, the guidelines for drinking water have been prepared by the National Health and Medical Research Council (NHMRC) and are based on WHO's standards.

Review questions

  1. Imagine that John Snow was arrested for breaking the pump handle and you were his lawyer. In your book, write your statement of his defence to the jury.
  2. In old books on etiquette, gentlemen were instructed to walk on the street-side of ladies, not on the building-side, when they were out for a stroll. Can you think of two possible explanations for this old-fashioned custom?

¹ Based on an activity from: Stephen Blackwell 1993, A Drink to Your Health, Melbourne Water and Science Teachers Association of Victoria.