Teeth hold the clues to Potchefstroom’s future
Article in Saturday Star, by Sheree Bega
For Dr Carl Albrecht, the answer to how uranium is contaminating Potchefstroom’s drinking water could be extracted from teeth – 60 perfectly formed adult teeth to be exact.
In the new year, dentists in Potchefstroom and Ventersdorp will start collecting teeth from willing donors in their respective towns. This is part of a groundbreaking epidemiological survey by the Cancer Association of South Africa (CANSA) that hopes to understand the uranium exposure of Potchefstroom’s 150 000 inhabitants who drink tap water that contains uranium, seeping from surrounding mine dumps and acid mine drainage.
That uranium causes kidney toxicity is well known, but Albrecht’s worry is the long-term threat of cancer.
“Uranium can act as a hormone disrupter, mimicking the action of oestrogen at very low concentrations, which could possible increase the risk for cancer and cognitive dysfunction. No emerging city can develop with such fundamental uncertainties that are not being addressed.”
Adult teeth ‘trap’ uranium. “It’s very straightforward to look at teeth because teeth bind and concentrate uranium. If you were to look at the teeth of a mature person, say a young person of 20 who goes to have wisdom teeth removed, those are the teeth we consider most useful because they’re very unlikely to be full of fillings.”
Thirty teeth will come from residents living in Potchefstroom for five years or longer and who have drunk only tap water.
These teeth are expected to “contain considerably more uranium compared wit similar teeth from long-term residents and tap water drinkers from Ventersdorp”, which is the control site.
The CANSA study is expanding on earlier research by Professor Frank Winde and colleague Kobus van der Walt, both of the North-West University, showing how calcite scales from kettles from Potchefstroom contained a 20 times higher average uranium level than similar deposits from kettles in Ventersdorp, where the dolomitic water is not affected by mining.
Albrecht is anticipating “similar, or even more pronounced” results come the middle of 2013.
“We’re boiling it down to a very simple concept – we’re asking the same question but instead of collecting kettles, we’re collecting human teeth. We’re assuming this is going to mimic the previous kettle experiment in some way.”
Wits University’s department of environmental chemistry will dissolve and analyse the teeth for heavy metals including lead and mercury while the Medical Research Council will determine statistical significance.
Winde’s earlier analysis of uranium concentrations in upstream water resources, from which the Boskop Dam gets the water that Potchefstroom’s residents drink, has shown significant increases of between six and 13 times higher averages since 1997. Winde explains there is a link between uranium levels in the dam and drinking water because municipal cleaning technology is not removing uranium.
“If he (Albrecht) finds nothing in teeth, the conclusion will be there’s no problem but we don’t know what the accumulation of uranium is in teeth because it hasn’t been investigated properly.”
Albrecht has traced a similar study in Brazil that showed the levels of uranium in teeth of residents of Caetite, a mining region, are over 30 times higher than the worldwide average.
“The uranium concentration in the tap water in Potchefstroom is very likely to increase substantially in time due to the inevitable closure of more and more mines and the existing pollution of the underground water with uranium will migrate closer and closer to Potchefstroom,” adds Albrecht.
“The municipality believes uranium levels are so low they don’t necessitate any concern, while environmental scientists are concerned the situation can only get worse… but to carry on with this debate about how much uranium is in the water is fruitless.”
Dr Pieter Henning, a dentish in Potchefstroom, believes the study is “sensible” given the uncertainty.
“If it’s the right specimen, then we’ll discuss with the person how we plan to use it. We’ll only take teeth that are either wisdom teeth already giving people problems or if there’s a space problem with pre-molars.”
There’s been an excellent response from dentists, adds Albrecht.
“These guys, to some extent, are holding the future of Potchefstroom in their hands.”