Rush to save KZN’s uMsunduzi River after disastrous toxic spill
The race is on to save the uMsunduzi River in KwaZulu-Natal after a massive, toxic spill of oil and caustic soda from Willowton Oil turned the river into a soapy mess, choking oxygen supplies to fish, plants, invertebrates and other aquatic life.
Appointed by the Willowton Group to evaluate the disastrous ecological damage arising from the recent industrial spill from its Pietermaritzburg plant, renowned river ecologist Mark Graham has not minced his words on the impact and the clean-up task ahead.
Graham, the director of GroundTruth, a highly rated environmental consultancy agency focused on water resources, said there had been no need to do autopsies on any dead fish to determine what chemical had caused the massive fish kill.
“It was not as if it was an unknown chemical source caused this. We had a smoking gun and knew what the calibre and type of gunpowder was that was used,” quipped Graham, referring to the industrial spill of 1.6 million litres of edible oil and caustic soda.
Willowton is the producer of household brands such as Sunfoil and Canola cooking oil as well as Sunshine D and D’lite margarines.
And it has not only been fish that have been affected, said Graham, but all forms of aquatic life, probably as far as Inanda Dam, more than 70km from the source of the pollution.
Willowton said the accident occurred when a colossal container collapsed, damaging two others and a bund (pollution containment facility).
The toxic mix spilled into the Baynespruit — a tributary of the uMsunduzi River. This did a couple of things, said Graham. First, it turned river water soapy, interfering with the critical dissolved oxygen absorption across the fish gill membranes. “This prevented the fish from being able to extract what oxygen was in the water. This same problem would also have affected aquatic invertebrates (insects) and other life in the water.”
Like the air we breathe, the survival of aquatic life depends on a sufficient level of oxygen dissolved in water.
“We have recorded low enough dissolved oxygen (DO) to confirm the cause (of deaths), which is also congruent with the characteristic fish behaviour while they were dying,” said Graham.
“It’s much like us sucking in a litre of soapy water into our lungs and then trying to breathe,” said Graham. “The detergent would coat the inside of the lungs, upset some very delicate chemistry at the lung interface with the air and prevent oxygen entering the lung tissues.”
Many fish had attempted to climb out of the water to escape the pollution. Others had jumped several metres out the water on to river embankments.
Graham said while fish were the most obvious and charismatic life form affected, there had been notable impact across the food web.
“We are now assessing these impacts, covering all levels of the aquatic system, from algae through to aquatic invertebrates (insects), algae, crabs and snails.”
Impact across the food web
Graham said this large die-off — possibly up to 80% of river life, say some — had created further problems with the decomposition of dead material causing a “microbial bloom”. This, in turn, was sucking up much of the residual oxygen in the water — a second hit to the few remaining fish and other aquatic life forms.
He said poor land use such as significant illegal sand mining in the lower reaches of the river were also compromising the aquatic ecosystem health and will hamper recovery, as well as ongoing sewage pollution in the upper catchment, mainly out of Pietermaritzburg.
“Fortunately, there has been dilution through the system,” said Graham, referring to steps that Umgeni Water took in flushing the uMsunduzi River with water from Henley Dam immediately after getting news of the disaster.
“This will continue to improve with time and as the summer rains flush the systems. We will be undertaking regular monitoring of the full system for at least a year to chart the recovery,” said Graham.
Duzi Disaster Fund
Graham welcomed the establishment of the Duzi Disaster Fund, a fundraising drive established by the Lower Mpushini Valley Conservancy to assist with the clean-up of the river around the conservancy which is situated less than 7km downstream of the Willowton Oil plant.
But much more needed to be done to restore river health from source to sea, said Graham.
“All efforts to clean up and focus attention on river systems are to be supported,” said Graham.
“However, longer-term initiatives to address the broader catchment degradation, pollution sources and impacts and finally restoration and rehabilitation would ensure a longer-term and more sustainable approach to the situation.”
He commended the work of the Duzi-Umgeni Conservation Trust (DUCT) which has “championed tirelessly” for many years for an ecologically healthy and biologically diverse uMngeni-uMsunduzi river system.
He said it was encouraging that after the spill, Willowton had engaged in discussions with DUCT about establishing a Baynespruit conservancy. The Baynespruit has for decades been rated as one of the six most highly polluted rivers in South Africa.
Willowton’s appointment of Graham as a consultant to evaluate ecological damage of the Duzi disaster and monitor and oversee remedial work has been widely welcomed in environmental circles.
“They could not have got a better person. He is the top riverine ecologist in the country. They will get a truly honest opinion on the real impact of the spill and what needs to be done,” said WildTrust’s recycling and waste operations manager Hannon Langenhoven. But Langenhoven warned:
“As long as we don’t have stricter controls on the continuous and habitual dumping of waste into rivers, the door is always open for big pollution like this.”
DUCT chairman, Dave Still, agreed.
“Sadly, the long-term trend in river health is going in the wrong direction,” said Still.
“This is due to chronic, daily pollution, which in Pietermaritzburg is really bad and getting worse. We really need the leaders of the city of Pietermaritzburg to decide if they have given up on our rivers or whether they are going to make a decision to turn the trend around.”
Still said while the Willowton spill had hit the uMsunduzi river “really hard”, there had been an unexpected positive spin-off in that it had refocused public attention on the health of rivers.
Encouraged by Willowton’s commitment, in principle, to establish a Baynespruit conservancy, Still said: “This may well turn out to be a real positive development arising from last week’s disaster.”
“Once we have an effective structure with a clear vision, money can be raised from a variety of sources. A few hundred thousand per year will do a lot. A few million will do more.
“The key to long-term sustainability is to get those who live and work near streams and rivers to adopt sections of those rivers. That way there is a direct connection between the people involved and the area where the work is done. Costs are lower and benefits are more immediate,” said Still. DM
This story was produced for Daily Maverick by Roving Reporters.