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Cinder-like material laced with dioxin has been used to build hundreds
of children’s playgrounds throughout western Germany according to a test
carried out by researchers last month. The federal republic’s environment
minister, Klaus Topfer, this week met environment ministers from the affected
states to discuss coordination and financing of a cleanup.

The red material, which contains dioxin concentrations some 1000 times
higher than present permitted levels, was a by-product of wartime copper
smelting at the Hermann Goering Works in Marsberg, North Rhine-Westphalia,
on the northern edge of the Ruhr. The slag, known as kieselrot, was marketed
as a construction material from the mid-1950s until 1968.

Now the states are asking for federal government help to find where
800 000 tonnes of it have been used.

Dioxin was discovered in the material last month, when scientists tested
a playground in Bremen. Kieselrot from Marsberg has been used for drainage
under playing fields and as a top covering on playgrounds. By last week
environmental officials had identified 300 sites where it has been used.
Officials also found that the cinders had been exported to the Netherlands.

The hazard to public health posed by kieselrot is not yet clear. Wolfgang
Rotard, a toxicologist from the German health ministry, says the risk depends
on how readily the dioxin contained in the material can be ingested. Dust
from the material is one problem. Children who eat dirt could be in potentially
greater danger. ‘It varies from site to site,’ says Rotard. ‘Where there’s
a great deal of dust or the soil is dry, the hazard is greater.’

Despite uncertainty about the risks, German environmental quality laws
call for a massive cleanup regardless of the financial costs. ‘On playgrounds,’
says Rotard, ‘the maximum permissible level is 100 nanograms per kilogram
of soil. In settled areas it is 1000 nanograms and in unsettled areas 10
000.’ These measures refer to ‘toxic equivalent’, which takes account of
the amount of particular dioxins in the material and their toxicity. Toxic
equivalents in kieselrot are as high as 100 000 nanograms per kilogram.

The variability of the sites means that different cleanup measures will
be needed. On playgrounds, recommendations include procedures such as covering
contaminated soil, or scraping it off and disposing of it elsewhere. The
soil can then be destroyed through incineration, or stored in landfills
or mines, says an official from the North Rhine-Westphalia environment ministry.

Rotard says dioxin exposure through soil is less dangerous than exposure
resulting from accidents like that at Seveso in Italy, where dioxin was
released into the air.

Tests at two chemical plants where dioxin was present in the air found
workers had blood dioxin levels about 1000 times higher than normal, says
Rotard. Recent epidemiological studies done at the plants have shown higher
than normal incidences of cancer among the workers.

Rotard says that researchers have also examined people exposed for long
periods to dioxin-contaminated soil. ‘We did tests on people who lived for
more than 20 years on contaminated sites, and we didn’t find the high blood
levels we did in factory workers,’ he says.

But the Germans are not taking any chances. According to Helmut Weber
of North Rhine-Westphalia’s health ministry, blood tests will be conducted
on Marsberg’s residents. The tests will cost DM3000 (£1000) per person.

If high dioxin levels are found then further tests will be taken in
areas where kieselrot has been used in construction.