Hong Kong government urged to monitor swimming pool water quality more stringently
Democratic Party finds that some water samples it collected contained chlorine below government standards and a possible carcinogen
There have been calls for more stringent monitoring of the quality of the city’s swimming pool water after chlorine levels in several samples collected from public pools were found to be below government standards.
The Democratic Party, which conducted the pool tests, also said the Leisure and Cultural Services Department should test for a possible carcinogen in regular monitoring of pool water quality after two samples were found to contain the substance in excess of European standards.
Among the 16 water samples collected from June 7 to 10, five, including those from Kowloon Park and Ho Man Tin, were found to contain chlorine below the standard set by the government.
Another sample from Kowloon Tsai was found to contain chlorine higher than the government requirement.
That came even though all samples were found to meet the requirements for pH value and total bacterial count.
Pool water is meant to contain chlorine, which is used to sterilise water, at a level of between one and three parts per million.
“If there isn’t enough chlorine, bacteria will grow when more people are using the pool,” said party lawmaker Helena Wong Pik-wan, who led the water study.
Excessive chlorine can also prompt irritation to the skin and respiratory system.
Meanwhile, two of the three samples tested for possible carcinogen Trihalomethanes (THMs) – which is not tested by the department – were found to contain the substance in excess of German and Swiss standards.
While there is no international standard for THMs levels in swimming pool water, the two European countries set the standard at not more than 20 parts per billion.
The level is not high enough now ... THMs are carcinogenic only if there is prolonged exposure
But samples from the main pools at Lei Cheng Uk and Sham Shui Po Park were found to contain 55.5ppb and 23.1ppb of the substance respectively.
THMs are produced when chlorine reacts with organic substances from swimmers, such as sweat, sunscreen and cosmetics.
“The department should include THMs in its surveillance for swimming pool water quality and set standards,” said Wong.
She said the department should remind swimmers to shower to wash away sweat and sunscreen before entering a pool.
Thomas Lo Wai-hung, a professor in applied biology and chemical technology from the Polytechnic University, said the findings in Wong’s study should not cause alarm.
“The level is not high enough now ... THMs are carcinogenic only if there is prolonged exposure,” Lo said.
A spokesman for the Leisure and Cultural Services Department said THMs were not one of the regulated chemicals in swimming pools as set by the World Health Organisation.
Pool water is collected once every hour for testing, including for chlorine, the spokesman said.
