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Row erupts over naturally occurring 'toxic' clay

A HOUSING developer in Wiltshire this week faces a bill running to thousands of pounds for disposing of naturally occurring clay, because the Environment Agency says it is contaminated waste.

Kimmerage Clay with high levels of calcium sulphate (gypsum) is being removed from the site of a Persimmon Homes development at Churchwood, Swindon.

The Agency has classified the clay as contaminated waste because sulphate levels exceed allowable thresholds. Persimmon has been ordered to dispose of it in a sealed landfill site, forcing its subcontractors to pay thousands of pounds in landfill tax.

The fear is that sulphates will leach into surrounding ground once the material has been disposed of, said Environment Agency Thames Region waste manager Mike Fletcher.

But independent consultant Julian Parry, who works for one of Persimmon's subcontractors disputed the Agency's ruling on grounds that sulphates cause no harm to humans or animals.

He also claims that calcium sulphate is almost non-soluble so the risk of leachates contaminating surrounding ground is very low.

Parry said the material should be classified as inert waste, exempting it from the landfill tax and making it suitable for use in landscape restoration at the local Peat Moor site.

Parry is arguing that the Agency's thresholds for measuring contamination are based on the criteria originally drawn up to assess industrial pollution arising from gas works.

They do not relate to naturally occurring chemicals, he said.

The Agency is also ignoring the fact that the Peat Moor disposal site where the clay is likely to be disposed of is founded on similar Kimmeridge Clay, Parry added.

The ruling will set a precedent for the countless sites across the country where there are high naturally occurring chemical concentrations, Parry warned.

Experts in environmental law described the Agency's approach at the Churchwood site as fiexceedingly cautious but difficult to fault'.

But it has huge cost implications for developers and companies undertaking largescale site restorations - for example on quarry, mining or landfill sites - will find it harder to source fill material, said partner at lawyer Simmons & Simmons, Kathy Mylrea.

Andrew Mylius INFOPLUS www. environment-agency. gov. uk

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