Perth's water supply well protected against giardia contamination

21/11/98

Water Resources Minister Dr Kim Hames said today Perth's water supply was well protected against contamination by big numbers of giardia or crypto sporidium parasites.

Dr Hames has just returned from a special meeting of the Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) in Adelaide which discussed the recent Sydney water scare.

"During the meeting, NSW Land and Water Conservation Minister Richard Sanderson-Amery said that while no clear reason for the high levels of parasites in Sydney's water had been established, the cause might have been the recent floods," Dr Hames said.

"He also said that despite apparently high parasite levels in the water, there have been no reported cases of either giardia or crypto sporidium infection in Sydney's population."

Dr Hames said an audit of risk factors undertaken by the Western Australian Health Department following the Sydney outbreak concluded that the likelihood of a public health scare in Perth was minimal.

"The department routinely carry out water quality testing on behalf of the Water Corporation," he said.

"On each occasion when metropolitan dams and other source waters were investigated, the parasites were either not detected at all or were at such low levels they posed little risk of entering the water supply system."

Dr Hames said the organisms did not naturally reside in scheme water and could not multiply in water.

"We are particularly fortunate in Perth with our water supplies," he said.

"Water catchments feeding the dams on the Darling Scarp are among the cleanest anywhere in the world.

"This is due to the foresight of earlier generations in keeping human habitation and agricultural development almost entirely out of the catchments."

Information received from the Health Department regarding the parasites included the following:

·      the parasites are not bacteria or viruses;

·      they can cause gastrointestinal upsets in humans but rarely caused serious disease unless the infected person already had a severely weakened immune system;

·      they can be transmitted from animal to person and from person to person but their transmission by water is rare; and -

·      there has been one reported instance of their transmission by a water supply in Australia.

Dr Hames said the Water Corporation and the Health Department had established a protocol to be followed in the event of giardia or crypto sporidium entering any water supply source in Western Australia.

Media contact: Caroline Lacy 9424 7450