Natural Resources Wales have issued a warning to stay out of the Afon Cegin in Bangor, following a sewage leak into the river.
Witnesses have seen human waste, nappies, sanitary products and condoms flowing through the river.
A statement from Natural Resources Wales issued on Monday evening said: “We’ve been working to prevent sewage leaking into the Afon Cegin from a commercial site near Bangor.
“The main source of sewage has now been blocked but we are investigating to see if there are any further sources.
“In this hot weather it is very important that children stay out of the Afon Cegin, which flows between Maesgeirchen Estate and the Llandegai Industrial Estate.”
A witness stated on Sunday: “Keep your children away from playing in the Afon Cegin, there is human waste, nappies, sanitary products and condoms flowing through the grid at the top of the river by the old mill. Welsh water are aware of the problem and are currently investigating the issue”.
