You’d expect that electricity power plants that produce uranium and thorium at more than ten times the normal background level would be unacceptable and unlikely to gain approval – but surprisingly that is not the case.

Even more surprising is that the contamination is not from nuclear power stations, but from the more widely-developed coal-fired ones.

Research from Russia and the American Oak Ridge National Laboratory suggests that coal-fired power stations are responsible for low-level radiation 100 times greater than nuclear ones. This can amount to five tonnes of uranium and 13 tonnes of thorium for a typical coal-fired power plant each year.

While a small proportion of these isotopes come out of the chimneys, the rest is concentrated in the coal ash which is dumped locally or made into cement or breeze blocks for construction. Disposal of this waste is a problem and much of it is close to the power stations, often in ponds.

Just last year, a sludge pond with millions of cubic metres of ash burst through surrounding dykes into the Tennessee river in the US, contaminating the downstream area with heavy metals, including arsenic.

Recent reports from the Indian side of the Punjab boundary, around the power stations in Bathinda and Faridkot, show concentrations of uranium in the groundwater and ash dumps 15 times above safe limits.

This is suspected to be the reason for the large number of local children born with serious birth defects. Many of the children are shown to have large levels of uranium in their bodies and are slowly being poisoned.

It is suggested that the source is more likely to be the power station coal rather than the granite deep underground or depleted uranium weapons used in Iraq and Afghanistan.

The burning of low-quality brown coal, for example from Eastern Europe and Australia, can produce excessive ash, though modern power stations have the technology to remove the sulphur dioxide that produces acid rain and the particulates that lower air quality.

It’s clear that coal, in both its mining and use, has killed many thousands in the past, from accidents to chronic lung diseases such as pneumoconiosis and respiratory problems, and now there seems to be a heavy metal impact too.

To make matters worse, burning coal produces climate-changing carbon dioxide, so there can be little justification for digging it out of the ground or ever calling it ‘clean coal’.