Thu, 1 Nov, 2012
Grahamstown's water quality has been affected by the floods, but it's a short-term problem according to Makana's Technical and Infrastructure Services Director, Thembinkosi Myalato. He said in a statement that while tests this week had indicated certain problems, the city's water was not toxic.
The municipality has again offered this assurance in an attempt to quell rumours fuelled by reports of cloudy and unpleasant-tasting water from household taps this week.
SMS and Facebook messages circulated last weekend warning that the city's tap water was toxic. In an email sent on Saturday to Rhodes students, expressing concern about the quality of tap water following the floods, Executive Director: Infrastructure, Operations and Finance Dr Iain L'Ange wrote: "We are recommending that until further notice, tap water should not be used for drinking purposes without taking additional precautions."
A combination of boiling and chemical disinfection was advocated. Rhodes Safety Health and Environmental Officer Nikki Kohly said on Wednesday, however, that the latest results of independent tests showed the tap water on campus was safe to drink.
An expert from the Amatola Water Board was whisked into town on Monday and on Tuesday a range of tests was run on samples from the Beaufort Street Police Station, the Environmental Health Office and the Waainek Water Treatment Works.
While Myalato said these confirmed that the water in Makana was safe to drink, the tests had revealed high levels of aluminium and more tests must be done to establish the reason for this.
"The main effects of aluminium in domestic water are aesthetic, relating to discolouration in the presence of iron or manganese," Myalato wrote. "Prolonged exposure to aluminium can have health implications, although this relationship has not been conclusively demonstrated."
"The results indeed are correct. There is a high amount of aluminium in the raw water," said municipal spokesperson Mncedisi Boma.
"We have sent samples of the water to a service provider in Port Elizabeth to establish what is the cause of the high aluminium content.
He emphasised that the aluminium was in the water source - the dam - and not in the tap water, however.
"We can also confirm that the water is indeed safe to drink," Boma said.
"The municipality wants to assure the community that this matter is being attended to with the support of the Department of Water Affairs and other private stakeholders," Myalato's statement read. "It is seen to be a short-term problem which will be solved soon."
Explaining the sequence of events leading to the water-quality concerns, Myalato wrote: "Due to heavy rains on the 19 October 2012 raw water that is abstracted from the Howieson's Poort Dam was found to be highly turbid and muddy and the treatment process was unable to clarify it to meet compliance standards for human consumption.
"Waainek Water Treatment Works which is treating this water was then shut off and the supply for Grahamstown was drawn from James Kleynhans."
He said a specialist from the Department of Water Affairs had come to Grahamstown on 24 October to help the municipality conduct tests.
The municipality also sent samples to Amatola Water and these were found to be South African National Standard-compliant with respect to microbiology, physical and chemical tests, "except aluminium content".
The water standard, known as SANS 241, is published by the South African Bureau of Standards.
Boma said Makana's water was tested every day by the municipality's Water and Sanitation services.
Commenting on Amatola's results, a member of the Kowie Catchment Campaign (who wishes to remain anonymous) confirmed that these showed the town's water complied with the standard, with the exception of aluminium and turbidity in the treatment works samples, and aluminium, iron and turbidity in samples from the town's taps.
Full comments from Kowie Catchment Campaign expert:
Final product water from WTW: all water quality determinands comply with SANS241 with the exception of aluminium and turbidity:
o The SANS241 standard for aluminium is an operational requirement, with a limit of < 300 mg/ℓ for operational purposes. This means that there is no established risk for human health, but because aluminium is frequently used as a flocculent, this should be considered a maximum.
o There are 2 standards for turbidity, one for operational requirement, one for aesthetic. The operational requirement is linked to disinfection – increased turbidity means less effective disinfection using chlorine. In this case, the standard for operations was exceeded (limit is 1 NTU), but remains within aesthetic limits of < 5 NTU (i.e. what people can see in the water).
Water samples from taps in town: all water quality determinands comply with SANS241 with the following exceptions:
o Aluminium: see also comment above. Both of these are higher than the final product water from the WTW (if this is the water source!).
o Iron: again, there are 2 compliance levels, i.e. aesthetic and chronic health. The police station sample exceeds the aesthetic level (300 mg/ℓ) but is well within the chronic health limit of 2000 mg/ℓ
(you can see iron before there are health implications). The sample from health office is well within aesthetic level.
o Turbidity: police station exceeds aesthetic limits, while sample from health office exceeds operational limit but is within aesthetic limit.
According to SAN241, there should now be a process of corrective action that must be implemented. Importantly, the following (p11 from SANS241-2: 2011):
“While non-compliance with the physical, operational and aesthetic numerical limits does not necessarily imply that the water is unacceptable for human consumption, it does indicate potential shortcomings that require resampling and implementation of corrective action in the treatment and distribution processes.”