High PH value in Hong Kong's freshwater was a factor for the city's drinking water regulator to overlook numerous alarms over the risk of lead-contaminated soldering materials, Director of

Water Supplies Enoch Lam Tin-sing told the inquiry commission on Monday.

The Water Supplies Department (WSD) is Hong Kong's gatekeeper of drinking water quality and it was Lam's first cross-examination before the independent commission of inquiry.

One major question arose over the fact the department had not prescribed a test for heavy metals, including lead, for certification of new water supply pipelines until the scare broke out last July.

The department collects about 160,000 water samples every year to test for microbes and chemicals to ensure that World Health Organization standards are met. Lam assured the commission all parties had duly performed their duties throughout the water supply line.

But he said it was the responsibility of individual residents to maintain and clean their water taps as officials are not authorized entry to private homes for regular inspection of water quality. Lam added that their priority was to ensure safe materials were used to build the pipelines.

Justice Andrew Chan Hing-wai, chairman of the commission of inquiry, challenged Lam, asking: "But shouldn't the duty of ensuring each resident drinks clean water be the top priority of the WSD?"

Chan also queried why the department had not been aware of risks associated with soldering materials contaminated by lead when other countries, including the US and the UK, as well as a local industry association, had warned about such risks in the past two decades.

Several reports and documents showed that the WSD had had "countless" opportunities to raise the red flag on the contamination risk, Chan held.

Lam only responded that WSD officers had never been aware that lessons learned in other places should set alarms ringing for Hong Kong as well, as Hong Kong had banned water pipes containing lead metal since 1938.

Officials thought the experiences of other countries were irrelevant, he added. This was because they assumed the higher standardized PH value of drinking water in Hong Kong, controlled within a range of 8.2 to 8.8, was more resistant to corrosion of heavy metals coated inside water pipes when compared with other places.

The commission was set up last year to investigate the causes of excess lead in drinking water after water samples collected from 11 public housing estates were found to be contaminated. Lam's cross-examination continues today (Tuesday).

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(HK Edition 02/02/2016 page7)

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