Hong Kong authorities have confirmed that black particles found in drinking water at some buildings in Taikoo Shing over the weekend were bitumen – months after similar incidents at other housing estates in the city.
The Water Supplies Department (WSD) said on Sunday that water pressure changes caused by water supply being redirected as part of pipe maintenance works “stirred up bitumen sediments in the pipes.”
“These sediments are inert substances and pose no harm to human health,” the WSD said in a statement on Sunday evening.
The investigation was prompted after residents in Taikoo Shing, in eastern Hong Kong Island, reported seeing black spots in their water on Saturday.
According to an earlier statement on Sunday afternoon, the WSD collected water samples from affected households, as well as from water tanks in buildings, for laboratory testing. The affected buildings, totalling 14, were mostly in phases four and five of the private residential development in Taikoo Shing.
It added that the investigation found damage to one of the filter facilities at the estate’s public water inlet, possibly causing a “small amount of sediment” to enter the water pipes and appear in drinking water.
The department routinely inspects inlet filters, it said, and the most recent checkup in early November showed no abnormalities.
Bitumen protective coating
In its Sunday night statement, the WSD said it had repaired the damaged filter and strengthened pipe flushing to clean the inner walls of the water pipes.
Cleansing of water tanks is also underway, and the WSD will continue to deploy water trucks and tanks to provide temporary water supply services to residents.
Bitumen is a common material used as a protective coating in water pipes to prevent rusting, though this practice was banned in 2005.
The findings in Taikoo Shing come after similar incidents at other housing estates earlier this year.
In June, authorities confirmed that bitumen and resin were found in drinking water at Queen’s Hill Estate and Shan Lai Court, both in Fanling.
A month later, bitumen particles were discovered at Grand Promenade in Sai Wan Ho.
After the Fanling incident, authorities said that Hong Kong had around 700 kilometres of water pipes that had a bitumen protective coating on their inner wall and that the WSD had installed over 1,000 screen filters “at suitable locations.”
They said it would review whether it is necessary to install more.
