/ 7 March 2024

State sets up task team to advise on water lettuce clogging Vaal River

Water Lettuce 2
In early February, AfriForum, together with several other organisations, businesses and community members, removed more than 1 623 tonnes of water lettuce from the Vaal River. Photo: AfriForum

The government’s formation of a technical task team to tackle the infestation of water lettuce in parts of the Vaal River is a welcome move but should not be a “once-off” intervention, according to WaterCAN, an initiative of the Organisation Undoing Tax Abuse.

On Tuesday Water and Sanitation Minister Senzo Mchunu and his counterpart at forestry, fisheries and the environment, Barbara Creecy, announced that they had established the task team to advise on Rand Water’s clearing of water lettuce, an invasive alien aquatic plant that is choking parts of the sewage-polluted Vaal River.

The team was formed after a public outcry over the use of glyphosate — a controversial broad-spectrum systemic herbicide — on the water lettuce in the Vaal River last month. 

These public concerns led to the government’s announcement that the spraying of the weedkiller on the water lettuce and water hyacinth, another alien invasive aquatic plant on the Vaal River, had been suspended.

“We’ve been saying thank you for actually listening to us, for listening to people and hearing what people are saying and holding back [on the spraying of glyphosate],” said WaterCan executive manager Ferrial Adam. “I think this whole technical team was formed because of the objections that people have to the spray, so that’s a good thing.”

Water lettuce, originally from South America, is a floating herb with rosettes of grey-green leaves, which form dense mats, completely covering a water surface. It clogs waterways and irrigation equipment; reduces water flow; impedes navigation, fishing and other recreational activities and provides a breeding place for mosquitos and bilharzia-carrying snails, according to Invasives South Africa.

The International Agency for Research on Cancer classified glyphosate as “possibly carcinogenic to humans”, while the African Centre for Biodiversity describes the weedkiller as a “risky pesticide at large” and unregulated in South Africa’s soil and water. 

“Glyphosate is a broad-spectrum herbicide that is water soluble. It causes damage to the soil, non-target plants and wildlife,” it said

In a joint statement, Creecy and Mchunu’s departments said the task team had identified immediate short and long-term interventions with clear outcomes to manage the situation. 

“The immediate short-term interventions include the revision of the integrated control approach, which, inter alia, will assess the use of a herbicide that is registered with the department of agriculture, land reform and rural development.” 

Adam responded: “But they are still going ahead with the spraying, so they are saying spraying is an option. And we say, ‘But why are they still doing that?’ Yes, it’s approved by the department of agriculture, land reform and rural development. But the problem is that it doesn’t matter if it’s approved by the department because, if it’s bad, they should not be using it. The world all over is saying it’s not a good thing to do. 

“We applaud that they listened to people, that they stopped spraying when we had objections, and having a technical team makes sense in getting the experts in to discuss it. But spraying still needs to be looked at because of the fact that it harms our water and that needs to be taken note of.”

The source needs to be sorted out, she said. 

“That is the sewage that feeds these aquatic plants, whether it’s water hyacinth or water lettuce. This is not a once-off solution. 

“They can’t form a committee and then in six months that committee is gone when the water lettuce has reduced. It has to be over a few seasons because this thing can lie dormant and then it can flourish again. 

“They have to have a long-term plan and part of that would be to deal with the system in place.”

The government departments said that, in the medium term, compliance and enforcement interventions would be intensified against the sources of pollution, “which are driving this situation”. 

Over the long-term, the Vaal River Catchment Strategy relating to invasive alien aquatic species will be reviewed to implement a strategy that will “holistically address the situation”.

The refurbishment of the Rietspruit, Sebokeng and Leeukuil wastewater treatment works would be fast tracked to reduce pollution “that is also contributing to the high eutrophication [when a water body becomes overly enriched by nutrients from untreated or poorly treated sewage]” of the Vaal River system.

Multiple control strategies deployed simultaneously — biological, chemical and manual removal of alien invasives — are under investigation by the task team “since a sustainable solution is required to manage the situation”, the departments said.