Paper producing giant Sappi has been identified in a massive effluent spill into the Mvoti River that has environmentalists and tourist businesses calling on the authorities to act.

On Tuesday the water flowing into the sea north of Ballito was black and smelt of sulphur, which, according to Sappi staff on the scene, could have come from the settling ponds at the paper mill outside KwaDukuza (Stanger).

Kevin Minogue, who runs an oyster-harvesting business and visits the area regularly, called on authorities to step in as the effluent discharge into the river was not only “regular”, but had effectively killed off all the oysters and mussels.

Sugar farmer Martin Finch, who also runs a small tourism business on the banks of the river mouth, said the situation was “unacceptable”.

“This is the southernmost migratory point for many northern hemisphere birds. We have many birding groups coming here from all over the world. We have bookings up until April next year.”

Pointing to the soapy, black and stinking water, Finch said he was embarrassed to bring tourists to the spot.

Archie Poustie, who manages two neighbouring guest houses, said they were fully booked for Christmas, “but I wouldn’t let my children swim in this”.

While Sappi failed to respond to questions, staff on the scene said effluent was being pumped from the settling ponds. They said the oxygen levels in the river were “very low” following tests.

Elias Bhengu of the iLembe District Municipality also blamed Sappi. “If it smells like sulphur, then it must come from Sappi,” he said.

Minogue said the mill had promised to “sort the problem out” by Monday afternoon when he reported the first signs of the effluent.

But by noon yesterday, it was still running strongly out to sea.

Gordon O’Brien, of the University of KwaZulu-Natal, who has studied the Mvoti River for 10 years, said the whole system was a tragic story.

“We are sending out a team next week when we will start with environmental monitoring.”

O’Brien said Sappi was not the only one that could be blamed for the degradation of the river.

“The sediment in the lagoon has deepened by 6m and that’s because of bad sugar-farming practices. Also, the river flows through KwaDukuza and then of course the municipal sewerage works also discharges into the river,” he said.

Themba Khumalo, of the Department of Water and Environmental Affairs, said steps were being taken.