The Japan Association for the 2025 World Exposition (hereinafter referred to as “the Association”) previously announced that Legionella bacteria above the standard values set out in the “Guidelines for the Prevention of Legionnaires Disease” issued by the Ministry of Health, Labour and Welfare was detected in seawater at the Water Plaza as a result of rapid PCR testing on 4 June. In response to those results, the Association suspended all water shows (the daytime performance “A Symphony of Air and Water” and the evening performance “Under the Midnight Rainbow”) at the Water Plaza from the night of 4 June.
The Association later announced that culture testing was simultaneously conducted on the samples of seawater of which PCR testing detected Legionella bacteria levels above the standard values. These culture tests confirmed that Legionella bacteria levels in all the samples were below the detection limit.
For Reference: Culture Method Test Results for Legionella Bacteria in the Water Plaza
https://www.expo2025.or.jp/en/news/news-20250620-04/
The Association has been collecting water samples every day since 16 June and inspecting them for Legionella bacteria using the culture method, while making technical adjustments to the equipment, etc., in preparation for the resumption of the water shows. On 9 July, we received the results of the samples taken up until 2 July. These results confirmed that although Legionella bacteria was present at levels expected in nature, the levels did not exceed the standard values set out in the “Guidelines for the Prevention of Legionnaires Disease”.
The Association consulted with experts to review the future water quality management of the Water Plaza. As a result, we decided to enhance existing seawater circulation with the installation of an additional pump between the Water Plaza and the Sea of Connections and to disinfect the seawater in the Water Plaza by regularly adding chlorine. The amount of chlorine added will be the minimum amount required for disinfection according to expert opinion. This amount has been confirmed to have no impact on the environment of the open sea. In addition, we will continue to carry out regular testing using the culture method to monitor whether Legionella bacteria levels remain below the standard value set out in the “Guidelines for the Prevention of Legionnaires Disease”.
The results of the culture tests for Legionella bacteria carried out to date and the Association’s future water quality management policy have been shared with the Osaka City Public Health Centre.
Now that the technical adjustments to the equipment have been completed, the water shows (the daytime performance “A Symphony of Air and Water” and the evening performance “Under the Midnight Rainbow”) at the Water Plaza will resume and be held daily from 11 July.
For more information about reservations for “Under the Midnight Rainbow”, please click here.
https://www.expo2025.or.jp/en/news/news-20250710-06/
We deeply apologise to all the visitors who were looking forward to the water shows. We will continue to take all possible measures to ensure the safety and security of our visitors and look forward to welcoming you to the water shows.