Hygiene officials yesterday were investigating the discovery of a bloodworm in an outdoor swimming pool in Shing Mun Valley, the second case in five days.
Although bloodworms are harmless, three pools managed by the Leisure and Culture Services Department were closed from 11am until 7.30pm after a swimmer told lifeguards on duty that he had spotted one in an outdoor training pool.
After the report, lifeguards inspected the pools and workers cleaned drains next to the pools. Hygiene officers also stepped up chlorination of the pool water and took water samples for testing, and government mechanics checked the filtering system.
A spokeswoman for the Shing Mun Valley pool in Tsuen Wan said the bloodworm discovery might be linked to the park next to the pools and to heavy rainfall yesterday morning.
On Tuesday, 30 bloodworms were found in drains at the Kowloon Park public swimming pool.
To prevent the mosquito larvae appearing in swimming pools, the Leisure and Cultural Services Department has implemented measures such as removing all artificial turf in pool areas. Swimmers have been advised to take showers and wash their feet before entering pool areas.