Eye in the sky finds poisoned sites

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The Independent Online

A detailed map of invisible mining deposits which have poisoned parts of Britain for centuries can now be produced, thanks to a revolutionary new space scanner that has been developed in Edinburgh.

A detailed map of invisible mining deposits which have poisoned parts of Britain for centuries can now be produced, thanks to a revolutionary new space scanner that has been developed in Edinburgh.

Dangerous waste products from lead and copper extraction pose a serious health risk, particularly as there has been no way to identify sites which may have been poisoned by medieval or Bronze Age workings.

But now archaeologists can pinpoint their location, thanks to the Endeavour space shuttle, which completes nine days of mapping the Earth's surface tonight. It has been fitted with a unique radar device that will enable scientists to construct a three-dimensional model of the Earth's inhabited terrain, providing a unique view of modern and ancient civilisations around the globe. A problem with one of the shuttle's thrusters had threatened to cut short the project, causing the six astronauts to scrimp on fuel.

The radar is capable of detecting precise topographical features, such as ancient tracks or slag heaps, which have been covered over by soil, making them invisible.

Dr Geraint Coles, a lecturer in environmental archaeology at Edinburgh University, said: "We know that Derbyshire, for example, is littered with ancient lead mines. But until now, we have had no way of knowing where the dangerous mining waste had been dumped."

The project team expect the data gathered to be used by public health authorities, conservation agencies and even insurance companies.

Children playing in back gardens built over these ancient dumping grounds are particularly susceptible to poisoning. Dr Erik Millstone, a senior lecturer at Sussex University specialising in chemicals and health, explained: "Children who put their fingers in soil or play with toys on the grass [growing over contaminated soil] and then put their fingers in their mouths, could easily build up high levels of lead in their bodies. Lead poisoning can cause intellectual impairment and retarded development in children."

Lead-based paint was still being used in houses until the 1960s, so the danger is not confined to ancient contaminants. But Dr Millstone agreed that it would be a great step forward in preventing lead poisoning if scientists knew where the ancient slag heaps were located.

Dr Gary McKay, a remote sensing archaeologist working with the Edinburgh University team, said: "We constantly flagellate ourselves about the pollution created by modern industrial methods. But the truth is the ancient practices were a lot worse. The Greeks and Phoenicians devastated their environment with un-processed lead, silver and tin. They also denuded countless forests."

Archaeologists can guess at ancient mining locations by focusing on places with a high incidence of Gaelic names referring to metals. But the waste materials were often dumped far from the mining sites.

Waste materials were often carried by boats and dumped along the coastline away from where people were living, added Dr McKay. As the world's population has mushroomed, more and more people have moved to areas near water as it becomes an increasingly scarce resource.

The Remote Sensing Archaeology and Visualisation of the Environment (Raven) team at Edinburgh will be minutely examining the radar data collected by Nasa's imaging radar on the space shuttle. The raw data will enable a three-dimensional map of the world to be constructed, which will be available to the public via the internet once the data have been analysed.

Radar penetrates to different depths depending on what material it is reflected against. So measuring the precise distance between the radar and the satellite will indicate where the lead and copper is buried beneath the soil. Copper poisoning is less dangerous than lead, but it can cause serious skin complaints.

The topographical model created by Raven will also be useful in detecting flood plains that are no longer apparent from visual examination. "This dataset is going to be a dramatic leap forward in hydrological mapping," said Dr McKay. It will offer planners much better data about the environmental dangers of building in certain areas.

It will also offer archaeologists valuable information about ancient civilisations. With a precise geological and topographical model, archaeologists will be able to examine not only the extent of mining activity, but also the routes of transport, landscape changes and environmental degradation.