Sources for this presentation
There is a transcript from BBC Newsnight on the 'Byker ash'.
Video on the Newcastle Toxic Ash Concern from the 1990’s
This is a PowerPoint presentation on the contamination of allotments, in Newcastle upon Tyne, in Northern England. The dioxin and heavy metal contamination was caused by the deposition of toxic ash, from the city's Byker incinerator, in the 1990's. The incinerator has now closed.
The main point from the video
In a Newcastle University report it was stated that the council should "consider establishing a register of allotment gardeners in Newcastle to enable health investigations if they should be required at a later stage".
To the authors' knowledge this inventory of allotment gardeners’ health has not been established. Therefore, the health implications, of the ash being deposited on the allotments are unclear.
This point was overlooked by a spokesman for Newcastle City Council; see this link on a BBC website. It is interesting to listen to the audio in the top right hand corner from Newcastle City Council.
Such health research could take decades to complete and even then could be inconclusive.
Atmospheric deposition from the Byker incinerator
A PhD thesis examined the effect of the incineration on the wider environment. "The key findings of this thesis were that the Byker incinerator did not appreciably contribute to levels of dioxin or heavy metal contamination in urban Tyneside, other than within the plant boundaries" (page 203). The incinerator could have led to atmospheric deposition on the surrounding area but this was limited.