Pofadder’s waters have poison bite
High levels of uranium a risk
THERE ARE few ways to make a living in the remote, arid and quaint town of Pofadder – South Africa’s own Timbuktu – other than running sheep. But new research has shown how potentially dangerous high levels of uranium in the region’s drinking water could be putting farmers and their workers at risk.
The team behind the study are now calling for greater governmental support for the provision of commercially available household water filters to improve poor water quality by significantly reducing uranium levels.
In their paper, “Uranium Contaminated Drinking Water Linked to Leukaemia – Revisiting a Case Study from South Africa Taking Alter native Exposure Pathways Into Account”, the researchers find that contaminated drinking water in Pofadder is the main uranium exposure for far m residents, resulting in uranium-uptake rates exceeding the World Health Organisation’s tolerable daily intake limit (TDI) by up to 900 percent.
In the paper by Professor Frank Winde and Ewald Erasmus – both of the mine water research group at North West University – and Gerhard Geipel of the Helmoltz Centre Dresden-Rossendorf, Institute for Resource Ecology in Germany, they warn that uranium displays “a range of chemotoxic and radiotoxic” properties.
The paper, which is published in the latest edition of Science of the Total Environment, is a follow-up to an earlier Water Research Commission study, which found a geospatial link between naturally elevated uranium levels in borehole water and haematological abnormalities in local residents, “serving as a proxy for leukaemia”, which an unnaturally high number of people in the area had contracted.
But while the original study focused on drinking water, the new research sought to explore alter native exposure pathways, including the inhalation of dust and the food chain. The researchers found that poor-quality drinking water is indeed the most “problematic” exposure pathway.
“Consuming tap water with the average uranium concentration found in the study area exceeds the World Health Or- ganisation (WHO) TDI limit by nearly 10 times (1 000 percent) for babies under one years and three to four times for adolescents and adults.
“The scenario obviously worsens for far m residents relying on the worst-quality tap water where babies exceed the TDI by nearly 18 times. Intolerable is the consumption of the worst quality water where the associated uranium intake is over 3 600 times above the WHO limit,” warns the study, noting the risk for babies and small infants drinking untreated borehole water is significant.
“While some farm owners use commercially available domestic water filter systems to clean borehole water before consumption, the farm workers mostly consume untreated groundwater as do all farm animals.”
Uranium levels detected in the grass and tissue of sheep generally reflected the uranium levels in nearby borehole water and exceed background concentrations by 20 to nearly 500 times, they found.
The research highlighted how uranium levels in most sheep tissue samples are well above average values observed in uncontaminated areas, with the highest accumulation occurring in skeletal parts such as wool and hooves, followed by inner organs and meat.
“For most, but not all sheep tissue, contamination increases with uranium levels in the consumed water.”
Mutton is the staple food consumed by some farmers – up to three times a day, including inner organs such as kidney, heart and liver, notes the paper.
“Most of the meat consumed by farm workers stems from older animals as the prime product, lamb meat, is mainly sold to the market.”
Combined with regular ingestion of contaminated mutton, “many farm residents who do not use filters are exposed to elevated chemotoxic health risks associated with their intake of uranium”.
“While regular consumption of brain is rather unlikely to happen, this is different for kidneys.
“Any person regularly eating kidney should be aware of the associated uranium intake, especially since other pathways and meat types further add to the load.
“The study finds uranium intake rates may be particularly high for largely indigent farm labourers relying mainly on offal complemented by gravy made from crushed bones.”
It also advises, in an apparent reference to the now-popular high-fat, low-carb diet, that far m residents should “limit consumption of meat to younger animals and avoid excessive intake of inner organs that, on average, show 50 percent higher uranium levels than muscle tissue”.
Winde also recommends pointing out boreholes from which water should no longer be used for animal or human consumption as well as installing household water filters on as many farms as possible.
There should be a national screening study to probe uranium levels of boreholes in other geological uranium provinces in the country because “similar situations are likely to occur elsewhere in arid South Africa. The phenomenon investigated in Pofadder is most probably only a small part of a much larger problem.”