A pile of disused tar and road rubble has been sitting in the Karkloof River for about two years, igniting fears that this could be polluting the water.The large pile of rubble has vegetation growing over it, and is blocking off one side of the river’s flow. It was dumped below a low-lying bridge.The Karkloof Conservation Centre, which initially discovered the waste at the end of last year, found that the part of the river where the tar was dumped was among the poorest in terms of quality in the river.The river runs to the uMngeni River, which enters the Albert Falls Dam, which services Durban and Pietermaritzburg.It is situated amid kilometers of farmland outside Howick.The conservancy, as well as uMngeni councillor Hazel Lake, believe the rubble came from contractors repairing nearby roads, but who dumped it remains a mystery.Twané Clarke, project co-ordinator at the Karkloof Conservancy, said she stumbled upon the rubble during an audit of the river system with other environmental groups last year.She said they had conducted tests to determine the “health” of the river at several spots, and they found that the water at the point where the rubble lay was “one of the poorest”.“No one really ever comes here and if we weren’t walking through this no one would have noticed this.“It is so irresponsible and could be dangerous because you can clearly see asphalt on the tar,” she told The Witness.Clarke said representatives from the Department of Water and Sanitation (DWS) had visited the site, but a resolution to clear the tar has still not been made.She does not believe local landowners would have dumped the tar.“Which farmer would dump this? They normally make use of this kind of material. Landowners here respect the river and we don’t find dumping or structures built on it,” she said.Lake said she had escalated the matter to the uMngeni Municipality. “Ideally an expert should have been sent out here. It should be a priority; it may be highly toxic and we should be taking it seriously,” she said.The uMngeni Municipality said on Thursday it did not know who the offender was, and appealed to the public to assist in identifying the culprit.“The matter has been discussed at length a number of times at our technical cluster portfolio committee meetings,” spokesperson Thando Mgaga said.He said the municipality cannot remove the tar without the go-ahead from the DWS.DWS spokesperson Sputnik Ratau confirmed the department was aware of the situation and will provide an update soon.