Froth on the Lagan mystery explained
Froth at the mouth of the River Lagan is "nothing out of the ordinary", according to officials.
The substance had been seen floating across the Belfast river, particularly around the Donegall Quay and Queen's Quay areas.
While foam on the Lagan can be a natural event, as a result of the water cascading over the weir alongside run-off from algae and vegetation, in certain circumstances it can be a tell-tale sign of water pollution further down the river.
However, according to a spokesman for Lagan River and Weir Team, the phenomenon is "quite normal".
He said: "There is nothing out of the ordinary. It is an urban river. We carry out water quality monitoring a couple of times a week, check for dissolved oxygen and temperature and we haven't had any reports of any pollution incidents on the river."
He added that "boatmen check the river every day" but as a precaution they would send a boat-team out to confirm this as a result of the query, adding that the foam usually dissipates within a "day or two".
The spokesman further stressed that his team are "into maintaining the water quality as high as possible" and encouraged everyone along the river, from walkers to those enjoying leisure-time, to report any signs of pollution.