Tokyo 2020 says venue water safe after 'screens' installed

Tokyo 2020 Olympic organisers said Friday that tests using underwater "screens" to filter water had successfully reduced bacteria at a venue for triathlon and marathon swimming.

The announcement comes after organisers revealed last year that prolonged summer rain had temporarily brought high levels of bacteria into the waters in Tokyo's Odaiba Bay.

Samples taken between July and September last year showed levels of e-coli bacteria more than 20 times higher than international standards, raising concerns about the safety of the venue.

In a bid to reassure competitors, organisers began testing this summer a system that uses screens to effectively quarantine an event area and filter the water inside.

They tested the use of single and triple-layer underwater screens, reportedly 20 metres (66 feet) long and three metres wide, during July and August, when the Games will be held in 2020.

"The triple-layer screens were shown to reduce the quantity of coliforms to well within targeted levels,' .