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Brimful of ash...

Austin Williams challenges the latest dioxin fears caused by a 'mountain' of incinerator ash in Essex, plus a round-up of some of the latest technical developments

Further to its original programme on the effect of dioxins in incinerator ash (AJ 2/9.8.01), Newsnight has again stirred up a hornets' nest with its programme on dioxins in construction materials (21.11.01), coinciding with the government's Waste Summit, on waste reduction and recycling.

The programme featured a 'mountain' of ash, which the presenter said contained dangerously 'high levels of dioxin, one of the most deadly chemicals known to man'.

Notwithstanding the fact that this rhetorical flourish has little or no substance, no real evidence was offered to justify heightening the panic reaction to the recycling of incinerator ash into blocks.

First, the ash mound in question was created before August 2000, when the policy on mixed ash became even more strict. Second, the notion that concrete blocks incorporating mixed ash pose a hazard to householders was suitably rubbished by Baroness Young, chief executive of the Environment Agency, who noted that bonding waste material to create inert products (blocks or road substrates, for example) was the best way to deal with residue from waste processes.

She told Jeremy Paxman that he was 'at more risk from me hitting you with (a block) than you are from sitting next to it.'

The ash, which was subject to the Newsnight inquiry, is situated next to the premises of Collease, a truck rental firm in Dagenham, Essex. Collease became concerned about the risks from the ash mound - which it alleges was blowing into its premises and making its staff ill - so the firm engaged EUS Laboratories to analyse samples of ash. No medical evidence was given to substantiate claims of ill health, although EUS's results confirmed an average level of dioxins at 747 nanograms per kilogram (ng/Kg), with peak readings of 1,200ng/Kg.

This compares with dioxin concentrations of 20-50 ng/Kg in 'average' urban soils.

Undoubtedly the mound is an unpleasant eyesore and should probably be removed. However, are the dioxin levels significantly high? Karl Pettit of EUS says that since he was not told where the samples were taken from (whether they were core samples, surface samples, or whether they were of the ash blown into Collease's property), nor was he given information on prevailing conditions or site activities that could have caused natural dioxin contamination, there was nothing to suggest that the whole mound should be condemned as dangerous. Even the high dioxin readings are relative to human exposure and 'no generalised conclusions can be drawn'.

Admitting, in the televised interview, that he would not let his children play on the ash mound, Pettit confided to me that he would not let his children play on any large mound of rubbish - but not necessarily out of a fear ofdioxin contamination.

David York of waste management operatives Ballast Phoenix says that his firm, and representatives of the Environment Agency, have results from the mound which are 'nowhere near those quoted on the programme'. But, more importantly, a quote from the Environment Agency (EA), which was used in the programme, was misinterpreted. The EA had written that the toxicity of dioxin in the mound was so low that, for it to be a health risk, it would have to comprise at least 0.01 per cent of the volume of the mound. However, the programme mistakenly took this to mean that the EA would consider 0.01 per cent by volume (or 100 million ng/kg) to be an acceptable level of dioxin. This is not the same thing.

Pettit confirms that 'you can't refer to dioxins in this way; volume percentages normally refer to chlorine content, not dioxins', and suggests that his comments on toxicity equivalents - prompted by Newsnight's interpretation of the EA quote - were taken out of context. To put things back into context, Pettit says that on 5 November more dioxins were released into the atmosphere from bonfires than from all the incinerators in the country over the course of a year.

However, you never know: far from this reassuring Newsnight, the programme might run a campaign to ban fireworks and dioxin-laden barbecues next year.

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