Are we starting to glow from the uranium in our environment?
Uranium in drinking water is a relatively recent concern, and Finland and Canada have been active in attempts to shed light on the risks of uranium exposure. The World Health Organisation has raised international awareness of this issue. The old limit values were based on radioactivity, but it is now appreciated that chemical toxicity is more important as a health risk.
The World Health Organisation re-evaluated uranium recently. Now the basis was its chemical toxicity, and the new recommendation for the limit value is 0.015 mg/l, while the previous value based on radioactivity was 0.1 mg/l. The radiation risk is not considered so high. The same applies for so called depleted uranium, whose radioactivity is lower than that of natural uranium. Its main problem is also chemical toxicity, not radioactivity.
The most important adverse effect of natural uranium is kidney toxicity, and this is the present basis for the health risk assessment. Some physiological changes have been detected in the users of tube wells in regions where there are uranium rich bedrocks. For example, increased excretion of calcium and phosphate to urine has been detected. The real implications for health are not yet known, and these continue to be studied.
There may be other adverse effects. An association with increased blood pressure has been observed. Uranium is concentrated in the bones and may cause structural changes in bone. It is not known if natural uranium can cause cancer. There is enough information already to limit exposure to uranium as much as possible. It does seem to be a problem in drinking waters in many parts of Europe.
Uranium in drinking water was revealed as a problem only recently when it was realized that its chemical toxicity is more important than its radioactive properties.
One level up: Is man defiled by what goes to his mouth?
Next chapter: Fluoride – friend or foe?