Response to Views on Water Quality of Public Swimming Pools
The following is a statement issued by the Leisure and Cultural Services Department (LCSD) in response to views expressed at a seminar on the water quality of swimming pools:
The LCSD endeavours to provide a clean and hygienic swimming pool environment for the enjoyment of the public.
When deciding the parameters for monitoring water quality of LCSD’s 36 public swimming pools, the Department has made reference to the “Guidelines for Safe Recreational-Water Environments: Swimming Pools, Spas and Similar Recreational-Water Environments” (“Guidelines” in short) issued by the World Health Organisation (WHO) and in consultation with the Department of Health.
Thirty LCSD’s swimming pools deploy ozone for sterilisation while the remaining six use hypochlorites and liquefied chlorine. Both methods are endorsed by WHO for sterilising pool water.
Acting on the “Guidelines”, the Department strictly and regularly monitors the turbidity, bacterial content, free residual chlorine level and pH value of pool water.
The Department tests the combined chlorine level of pool water annually. Test records showed that the content has been less than 0.1 part per million (ppm).
At the seminar, some suggested that Trihalomethane (THM) or Chloroform in pool water should be monitored. According to the “Guidelines” issued by WHO, Trihalomethane (THM) or Chloroform is not one of the parameters to be monitored for pool water. The content of these chemicals found in pool water is extremely low and they will also be disintegrated in the sterilisation process.
The Department has been monitoring the Oxidation and Reduction Potential (ORP) of the pool sterilisation system and maintaining the level between 750 and 800 millivolts to ensure the efficiency and bacteria-killing power of the sterilisation system.
In accordance with the Swimming Pools Regulation, the turbidity of pool water is kept at 5NTU or below and the standard is monitored weekly.
The free residual chlorine level adopted for the public swimming pools meets the standards recommended by the “Guidelines” and is monitored on an hourly basis.
To enhance the management of public swimming pools, the Department set up an interdepartmental body - the Steering Committee on the Management of Public Swimming Pools in November last year.
Representatives from the Department of Health, Electrical and Mechanical Services Department, Architectural Services Department, Food and Environmental Hygiene Department and Agricultural, Fisheries and Conservation Department serve as members of the Steering Committee. Two experts - Professor Yuen Kwok-yung, Head of the Department of Microbiology, Faculty of Medicine of the University of Hong Kong, and Mr Victor Cheung Chi-kong, Council Member of the Hong Kong Institute of Engineers - serve as the advisers.
The Steering Committee aims to monitor the pool water quality, environmental hygiene and cleanliness.
In accordance to the recommendations made by the Steering Committee, the Department has implemented a series of proactive measures to upgrade the hygiene and cleanliness of public swimming pools, as well as to step up the monitoring of the pool water quality.
These measures include strictly conducting daily cleansing operations and carrying out thorough cleansing weekly, increasing the frequency of tests on bacterial content and how clear the water is on a weekly basis.
In order to increase the degree of transparency and allow people to know more about the water quality and hygiene level, notices have been put up at the entrance to every public swimming pool showing details of the respective water sample tests. The public may also browse the Department's website at http://www.lcsd.gov.hk
for the information .
The Department will closely liaise with the Architectural Services Department and the Electrical and Mechanical Services Department, and take note of the latest development of swimming pool sterilisation systems around the world and in the global market so as to examine and evaluate the need and feasibility to introduce new technology.
An opinion survey conducted from June to September this year at 36 swimming pools managed by the Department revealed that over 70 percent of more than 8,200 randomly selected respondents were satisfied with the pool water quality and the overall cleanliness of the pools. They also agreed that measures implemented by the Department are effective in upgrading the standard of hygiene and cleanliness.
Ends/Tuesday, November 8, 2005