Banned but harmless substance found in 2 Hong Kong housing estate freshwater pipes
Black particles found in the freshwater supply at two public housing estates are mainly bitumen, authorities have said, stressing that the water is safe to drink.
Director of Water Supplies Roger Wong Yan-lok sought to reassure the public on Thursday after government tests revealed the presence of the substance – which is banned from use in pipes – in most of the 126 samples collected from blocks in Queens Hill Estate and Shan Lai Court, both in Fanling.
'Bitumen is insoluble in water and is not harmful to humans,' he said.
Wong added that experts commissioned by the Water Supplies Department five years ago did not find any toxic substances in three litres of hot water boiled with 10 grams of bitumen.
'Even if residents drink water containing bitumen, there is no need to worry,' he said.
Hong Kong's Global 6K for Water run highlights need for clean water
Residents at the two public rental and subsidised estates first reported the presence of black particles in their drinking water last Friday, prompting some to buy bottled water as speculation grew over the source of the mysterious dark specks.
Wong said the amount of bitumen – a black, sticky substance obtained from crude oil – found in the current samples was three-thousandths of the quantity per litre used in the department's past experiment.
The latest tests showed the bitumen was found to be mixed with resin, a thick substance typically produced by plants.
Wong said the pipes supplying freshwater to the two estates, completed between 2021 and 2022, were not lined with bitumen. The substance has not been used as an inner coating material in pipes laid after 2005.
Residents of two Hong Kong public estates have started buying bottled water after finding black particles in their freshwater supply. Photo: Dickson Lee
He said authorities believed that the bitumen could be left over from 2022 when the government received reports of a large amount of sediment flowing into the pipes of Queens Hill Estate.
The sediment could have stayed in the pipes when Queens Hill Estate was used as a quarantine facility the same year. Wong said authorities had cleaned the pipes and installed equipment that could filter out substances larger than 0.1mm in December 2022.
He noted that some sediment remained in the plumbing system, with the pieces becoming smaller and able to move over time. Wong also said the resin might be coming off the coating of valves in the plumbing.
The government will step up efforts to clean the residue in pipes and test the water quality daily until the problem is solved, Wong added.
Listen Up: Scientists uncover germs hidden in reusable water bottles that need cleaning
Authorities will also replace materials in valves when necessary, while additional filters will be installed at every block of Shan Lai Court.
The department later said it would upload its water test results daily on its website, adding that records showed the upper stream of the supply system in the area had a section that used bitumen as the inner coating material.
Despite repeated assurances over the safety of the water supply, residents have continued to voice their worries, with a mother at one of the estates finding that black particles stuck to the surface of bottles when she tried to prepare baby milk formula.
Asked whether he would apologise to the public, Wong said he could present his reassurances 'in another way' in the future to address public concern.
A resident wraps a tap with tissue to filter out black particles. Photo: Nora Tam
Wong King, executive president of the International Institute of Utility Specialists, said the bitumen could have come from old pipes outside the Queen's Hill neighbourhood. He added that bitumen could have also fallen into the pipes accidentally when the estates were being built.
He said he believed that the incident was an isolated case, adding that it would be sufficient for authorities to clean the plumbing system rather than reinstall the pipes, as the latter would be inconvenient for residents.
Drinking Water Safety Advisory Committee chairman Chan Hon-fai said it was possible that the substance came from old public pipes and had remained in the upper stream of those in Queen's Hill.
He said that sediment could not be washed away initially, as the water velocity was low, with very few residents moving into Queens Hill Estate a few years ago. As more residents moved in, the water velocity would increase and push sediment out through taps in flats, Chan added.
He suggested that authorities use technology as they continue to clean the pipes: 'I believe they can deploy small robots to check whether there is sediment remaining in the pipes.'
Chan stressed that the water was safe but advised residents against consuming the particles.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
South China Morning Post
10 hours ago
- South China Morning Post
Xia Baolong meets Hong Kong district officers and visits ‘community living room'
Beijing's point man on Hong Kong affairs has met district officers and toured a 'community living room' on the final day of his inspection visit, the Post has learned. Hong Kong and Macau Affairs Office (HKMAO) director Xia Baolong spoke to the chairs of the city's 18 district councils at the government headquarters in Admiralty on Sunday morning, according to sources. He then headed to a community living room operated by the Tung Wah Group of Hospitals in To Kwa Wan at noon. Beijing liaison office chief Zhou Ji, Chief Executive John Lee Ka-chiu, and Secretary for Labour and Welfare Chris Sun Yuk-han were seen visiting the facility with him. The spaces are a government initiative to ease the pressure on the tenants of Hong Kong's subdivided flats by providing them communal areas for cooking, dining, studying, showering and doing laundry. There are now six such facilities, mainly in Kowloon.
South China Morning Post
18 hours ago
- South China Morning Post
Hongkonger channels mental health recovery into designing fashion collection
For two years, Hongkonger Ng Mei-ling only left her flat for regular visits to a psychiatrist. She said she had to quit her clerk job after she was diagnosed with depression and anxiety disorder due to work pressure in 2017. Her symptoms had worsened. She had a rapid heartbeat, hand tremors, insomnia and a lack of appetite. 'I couldn't accept my illness at first,' Ng said. 'I stayed at home and didn't go out at all unless I had to see a doctor.' Ng is at ease recounting this particularly dark period of her life and has even gone on to design a collection of clothes that tells her personal story of recovery from mental illness and raises public awareness about the condition. 'In fashion design, I discovered I was able to have achievements and I shouldn't underestimate myself,' she said.
South China Morning Post
2 days ago
- South China Morning Post
Vulnerable groups in Hong Kong should get Covid-19 vaccinations: medical expert
Hong Kong's vulnerable groups should get vaccinated against Covid-19 infections once a year as new outbreaks will occur every six to nine months, a medical expert has urged. David Hui Shu-cheong, a professor of respiratory medicine at the Chinese University of Hong Kong, made the appeal on Saturday while pointing out that the current wave of Covid-19 infections had been declining since late last month and could end in July or August. 'The current outbreak started in April, peaked at the end of May and is now beginning to subside,' he told a radio programme. 'High-risk groups such as the chronically ill, children, the elderly and those with weakened immunity, can easily develop complications such as pneumonia, respiratory failure or even fatalities once infected with the Covid-19 virus.' Authorities have reported six severe paediatric Covid cases so far this year, none of which have been fatal. Two had underlying illnesses and four were unvaccinated. Hui said as Covid-19 antibodies were not long-lasting, there would be periodic decreases in overall community immunity and new outbreaks occurring in cycles – about once every six to nine months.
