Water affairs officials are unable to tell MPs whether the health of South Africa’s rivers is improving or worsening, but a rash of red spots across maps they presented suggested the latter.
Briefing members of Parliament’s water and environmental affairs portfolio committee, the department’s acting chief director for water resources information management, Moloko Matlala, listed the main problems affecting the quality of the country’s river water.
These included fecal pollution, eutrophication (the inflow of nitrates and phosphates), high salinity, high toxicity (from, among other sources, agricultural pesticides) and acid mine drainage.
Displaying a brightly coloured map of the country’s main river systems, Matlala advised the committee: “When you see red dots, you know there are problems.”
In what he described as a “snapshot” in time (June this year) of the microbiological state of rivers, large red dots are clustered like bunches of grapes along certain Western Cape, Gauteng, North West Province, Mpumalanga, KwaZulu-Natal and the Eastern Cape water courses.
They indicate the water from these rivers, if drunk untreated, poses a high risk to those consuming it due to the presence of “mainly Escherichia coli, but in some cases fecal coliforms”.
E. coli and fecal coliforms are bacteria found in human feces. They are linked to diseases such as cholera and typhoid.
Another map displayed by Matlala showed the risk of eating “raw” crops from agricultural lands irrigated with untreated river water. Here, red as well as yellow (indicating “moderate” risk) dots occur mainly in the Western Cape, Gauteng and the Eastern Cape.
A third map suggests that swimming in certain rivers in many areas of the country could be a dangerous form of recreation, especially in parts of Gauteng and North West, but also in the Western Cape (the Berg River) and certain Eastern Cape and KwaZulu-Natal water courses.
Matlala singled out some rivers for special mention.
“The Vaal River system and Orange River [near the confluence of the two] are impacted due to… mining activities, irrigation, power generation and sewage effluents.
“The Waterval, Blesbokspruit, Natalspruit and Klip rivers are also affected by effluents from waste water treatment plants and industries.”
He said the lower Crocodile River had elevated salinity and phosphate concentrations, and posed a concern, especially with respect to irrigation.
“The upper Crocodile River [is] polluted by effluents from gold mining activities and effluents from waste water treatment works. The trophic state [the phosphate and nitrogen content] of virtually all the dams in the Crocodile River catchment is very high, and algal blooms are common.”
Freshwater algal blooms are the result of an excess of chemical nutrients, particularly phosphates.
Matlala said that in KwaZulu-Natal, the Umgeni River, which flows out to sea near Durban, had high phosphate levels due to “poultry farms, effluent from cattle feed lots and informal settlements without sanitation facilities” along its banks and feeder streams.
The province’s Umlazi River was “heavily impacted due to… sewage effluents discharged into the river”. Ironically, the river’s name stems from the isiZulu word “umlaza”, which means sour tasting.
Matlala said a solid waste site close to the river as well as discharges of industrial effluent by a textile factory were also affecting its water quality.
In the Eastern Cape, the Umthatha River carried high levels of nutrients and fecal pollution “due to overflowing sewer manholes and overloaded waste water treatment works”.
Along the coast, the Buffalo River was similarly affected, though upstream it remained “pristine”.
Matlala also warned that sulphate concentrations in the Witbank, Middelburg and Loskop dams were increasing, and exceeded quality standards.
The department’s acting deputy director-general for water resources management, Mbangiseni Nepfumbada, was unable to say whether the health of the country’s rivers was improving or worsening.
Responding to a question on this, he said it “needs to be looked at”, adding that no data was immediately available.
According to a document tabled at the briefing, titled “Report on the State of Rivers and Dams for 2010-2011″, high salinity levels — caused by chemicals such as sulphates, chlorides and sodium — is a “huge” water quality problem across South Africa.
“These are mainly produced in areas where there are activities such as mining, agriculture [and] irrigation… .”
It notes that water quality is not always monitored regularly.
“Some areas are not monitored regularly, or not at all, due to human and financial constraints.
“Fecal pollution and pesticides are not monitored widely, yet they pose health risks to human and agricultural activities,” it states.
Source: Sapa | 17 August, 2011 14:44