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A danish nuclear physicist will arrive in Ukraine next month armed with
a plough designed to make the land around the Chernobyl nuclear plant safe
to farm again. The plough, which Jorn Roed invented at Riso National Laboratory
in Roskilde near Copenhagen, scrapes off between 3 and 10 centimetres of
the top soil, and then buries this layer about 45 centimetres below, all
without disturbing the intervening soil.

‘The radioactive caesium and strontium are concentrated in the top few
centimetres of soil in fields in Ukraine,’ Roed says. In some cases the
radiation levels are high enough to be a problem for people working in the
fields or living next to them. A conventional plough could bury the top
layer, but it would turn over the soil and bring the lower layers to the
top. ‘In many contaminated areas,’ Roed says, ‘the soil 30 or 40 centimetres
below the surface is so poor that bringing it up would drastically cut the
productivity of the field.’

Roed says that this long after the accident at Chernobyl the radionuclides
are firmly bound to soil particles, and that burying them under half a metre
of soil will almost completely shield people using the fields from radiation.
It would also lessen the amount of radiation that crops in these field take
up through their roots.

The plough works by making two passes: on the first pass, it digs a
furrow, and on the second, it scrapes off the top layer from an adjacent
strip, dumps it into the bottom of the furrow, and then pushes the next
layer sideways to cover the furrow. ‘The first two or three furrows do not
work so well, Roed says, ‘but then the rest of the field goes smoothly.’

He believes that if Ukrainian officials decide to use the plough after
tests this June, much of its effect will be psychological. The radiation
levels in some contaminated areas may not be a serious hazard but the people
are terrified of the radiation says Roed. Having their fields ploughed will
provide some reassurance, he adds.

Two ploughs have been built so far, by the Danish company Bovland. The
second is now in Greece, being tested on soil that was contaminated with
nonradioactive pollutants. ‘There may be a large market for this plough
in areas contaminated with heavy metals and agricultural chemicals,’ Roed
says. ‘We have even had a query from a farmer with a field whose topsoil
contains screws, bolts and other debris from a scrapyard.