There has been yet another spillage of effluent into the Duzi, this time through an ageing sewer pipe and the culprit is unknown at this stage.
Lower Mpushini Valley Conservancy chairperson Pandora Long said on Thursday that the substance has left the water “murky white and oily”. River users on the Baynespruit first noticed the river turn white and “scummy” a couple of days before downstream users at Grimthorpe Road and in the Lower Mpushini Valley sounded the alarm, she said.
A report from the Duzi Umngeni Conservation Trust (Duct) said that a large ageing sewer pipe that contains trade effluent corroded and spilled into the Duzi via the Baynespruit.
Long said a number of landowners in the Lower Mpushini Valley rely on the water from the Duzi for domestic use, livestock and crops. It is also needed by downstream users in Nkanjezini and KwaXimba.
Director of GroundTruth, Dr Mark Graham, said it does not appear that any fish have been killed, although there is undoubtedly some impact on an already stressed river system.
“We have been in touch with industries in the area and it does not appear to be a direct industry spill,” he said.
It appears to be linked to a sewerage pipe leak and it certainly contained quantities of oil — probably cooking oil, he said.
“The question is, how did this material get into the sewer, as this material should strictly be restricted from entering the sewer lines?”
This highlights the importance of the proposed Baynespruit Catchment Conservancy that Duct was developing in conjunction with key roleplayers and the municipality in the area, where issues of monitoring, compliance and the maintenance of key sewerage infrastructure could be addressed.
In the short term the municipality must undertake to repair and maintain the sewer lines, he added.
Msunduzi spokesperson Thobeka Mafumbatha said that its environmental health unit was informed of a possible discharge into the Baynespruit and ultimately the Duzi River.
A team was deployed to trace the discharge and started at the Prilla 2000 bridge all the way to the Lincoln Meade bridge.
“Four samples have been taken which will be analysed for pH, turbidity, chemical oxygen demand, sulphate and phosphates, which will assist in narrowing down a possible offender. The water and sanitation team is also tracking the course of the river to identify possible overflowing sewer manholes,” she said.
A foamy sludge was seen at the Sobantu low level bridge as well as the Lincoln Meade bridge.
The two edible oil manufacturers within the area were inspected to determine if there was any accidental or deliberate spillage into the river. All their discharge points appear to be relatively dry. Mafumbatha said that during the tracking, the team was alerted to a storm-water drain discharging into the Baynespruit, further upstream from the two oil manufacturers. Oil was clearly evident. She added that since it is a municipal mainline, identifying the offender will be difficult and may require the use of cameras to detect the oil discharge point.
This will be done as soon as possible, but the team expects that this may have been a once-off incident. It also appears that the illegal discharge is still impacting on users downstream, although it is being diluted.
The water results are expected next week.
Should a perpetrator be identified, legal action will be taken, added Mafumbatha.