Siza Water has launched an investigation after water quality tests in Sheffield Beach last month identified elevated levels of some disinfection by-products.

The matter was raised by resident Barry Gould, who commissioned independent laboratory testing of his tap water after a recent Parkinson’s disease diagnosis made him more conscious of environmental exposures. Gould stressed that he was not suggesting the water had caused his condition, but that he was attempting to take stock of everything that could possibly affect him.

“I want to do everything I can to limit the progression of the condition,” said Gould.

The Talbot Laboratories report found bromodichloromethane at 71µg/l (parts per billion), above the SANS 241:2015 guideline value of 60µg/l. The combined trihalomethane (THM) ratio was 1.95 against a recommended maximum of one. Other tested parameters complied with requirements, while E. coli and total coliforms were not detected.

Gould said he was concerned about whether residents could be exposed to elevated THM levels over extended periods and called for regular monitoring and corrective action where necessary. THMs can form when chlorine used to disinfect drinking water reacts with naturally occurring organic matter.

After the Courier approached Siza Water about Gould’s results, the utility sampled several points in its distribution network. Siza Water spokesperson Sihle Mathenjwa said samples were taken at Zululami Estate, the Zululami bulk meter connection, Taffeni Reservoir and a customer connection on August 28.

“The laboratory’s interim results indicate that certain trihalomethane ratios exceeded the recommended SANS 241:2015 guideline value,” said Mathenjwa.

She stressed, however, that microbiological safety remained the primary public health objective of drinking water treatment.

“The free chlorine residuals measured at the sampled locations remained within accepted operational ranges and indicate that effective disinfection was being maintained throughout the system,” she said.

Siza Water has begun further investigations and is engaging with its bulk water supplier, Umngeni-Uthukela Water, to establish the source of the elevated THM levels.

The utility will determine whether additional measures are required and plans further sampling and confirmation testing once it receives the final signed laboratory report.

“At this stage there is no indication that consumers should discontinue normal use of the water supply,” said Mathenjwa.