XN000022-1977-09-03 — Page 5

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SATURDAY, SEPTEMBER 3, 1977

BUT UNFORTUNATELY THE WORK OF THE WATER QUALITY CONTROL UNIT CAN BE UNDONE LOCALLY, PARTICULARLY BY THE PLUMBING SYSTEM ON CONSUMERS' PREMISES.

MR. MAKER SAID THAT CORRODING PIPES IMPART A YELLOWISH-BROWN DISCOLOURATION AND TURBIDITY OFTEN NOTICED ON FIRST TURNING ON A TAP.

+THIS IS DUE TO IRON RUST AND IS EXPERIENCED IN MOST PARTS OF THE WORLD WHERE GALVANISED IRON PLUMBING IS COMMONLY USED BUT IT IS QUITE HARMLESS TO HEALTH.

+ANOTHER PHENOMENON WHICH SOMETIMES GIVES RISE TO CONCERN DURING THE CURRENT RESTRICTIONS IS 'MILKY OR WHITE'' WATER.

.

+

+THIS IS CAUSED MAINLY BY THE SUDDEN RELEASE OF EXCESS DISSOLVED AIR IN THE FORM OF TINY BUBBLES, BUT ON STANDING A MINUTE OR TWO, THE WATER WILL CLEAR,+ MR. MAKER SAID.

TURNING TO THE QUESTION OF BOILING DRINKING WATER, THE SENIOR WATERWORKS CHEMIST SAID THAT WHEN RESTRICTIONS ARE IN FORCE, +ALL DRINKING WATER SHOULD BE BOILED AS A PRECAUTION BECAUSE THERE IS A SLIGHT RISK OF CONTAMINATION ENTERING DE-WATERED PIPES, BUT WHEN FULL SUPPLY IS AVAILABE IT IS PERFECTLY

SAFE SO LONG AS ANY PRIVATE STORAGE TANKS ON PREMISES ARE PROPERLY PROTECTED AGAINST CONTAMINATION.+

ASKED TO DEFINE THE CHARACTERISTIC OF A GOOD WATER SUPPLY, MR. MAKER SAID:

* THE WATER COMING OUT OF THE TAP SHOULD BE CLEAR AND

COLOURLESS, FREE FROM TURBIDITY OR OPALESCENE DUE TO SUSPENDED MATTER=

* PALATABLE WITH NO UNPLEASANT ODOUR OR TASTE=

*

REASONABLY +SOFT IN ORDER TO PRODUCE A GOOD LATHER WITH SOAP- AND

* FOR INDUSTRIAL USE IT SHOULD HAVE A LOW DISSOLVED MINERAL

SALTS CONTENT.

BUT MR. MAKER SAID ABOVE ALL ELSE, THE WATER SHOULD BE SAFE TO DRINK.

+ IT SHOULD HAVE NO DISEASE PRODUCING BACTERIA OR OTHER ORGANISMS AND HAVE NO HARMFUL CHEMICAL CONTENT.+

MEASURED BY THESE STANDARDS, HE CONCLUDED, THE WATER SUPPLIES DEPARTMENT PROVIDES THE CONSUMERS OF HONG KONG WITH A GOOD WATER SUPPLY.

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