Brussels Canal has turned green with algae over the past week, with dead fish and heavy pollution reported, as low oxygen levels worsen water quality.
The canal has taken on a greenish colour because of the algae bloom, Belga News Agency reports. Dead fish have also been found in the water, apparently due to a lack of oxygen, it noted.
Brussels Environment has confirmed the presence of green algae and said it will send a team to the site as soon as possible.
Pieter Elsen, founder of the City To Ocean association, said the exact cause of the sudden spread of algae was not yet known. However, he said it was linked mainly to fertilisers and organic matter present in the canal’s sediment.
He added that under normal conditions, meaning when it rains regularly, Brussels’ sewers overflow once to three times a month. At those times, wastewater mixes with rainwater before flowing into the Senne and the canal.
Although the last overflow dates back to late July, the sediment still contained large amounts of organic material, Elsen explained. It is therefore essential to keep as much rainwater as possible out of the sewage system in order to prevent an overflow, he said.
According to Elsen, when rainwater and wastewater mix and spill into waterways, they bring in large amounts of organic matter, encouraging algae growth. As a result, fish are deprived of oxygen.
He said he could not state with certainty that sewer overflows were the main cause of the green algae. However, City To Ocean hopes to reduce the problem through a new campaign called Disconnect your Roof, which aims to divert as much rainwater as possible away from the sewage network.
The group visits residents to renovate water tanks or install drainage and infiltration systems in their gardens, he said.
