Tittabawassee River Watch Editorial
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Paul Hanly 04/08/05, reader opinion to MDN 04/06/05 article
Paul Hanly Apr, 08 2005 International Dioxin News:
Dioxin standard to be tightened to 90 parts per trillion for top metre of Australian residential site.
In Rhodes, a suburb of Sydney, Australia, the new remediators (Thiess Services) of a dioxin contaminated site which had an approval to have dioxin to 1000 ppt in the top metre of remediated soil have applied to the NSW Government to have the allowable dioxin in the top metre of remediated material (ignoring landscaping cover expected to be about 18" (500 mm) thick) reduced to less than 90 parts per trillion. The remediator's health risk analysis for an adjoining site found that to protect childrens health the amount of dioxin in surface soils had to be less than 90 pp trillion. This is because of children's lower body weight and because many children eat dirt, a habit called pica.
Thiess is also seeking approval to replace an existing approval for a direct thermal desorber with after burner (incinerator) which had no cyclone, no rapid quench and no wet scrubbers and was originally designed for service station remediation, with one that is desighned to operate at higher temperatures and has the pollution controls missing from the earlier machine.
Michiganís' standard of 90 parts per trillion is being adopted in other parts of the world based on health studies! Why would Michigan abandon it, particularly when Americans have a food chain much more contaminated by dioxin than Australia or New Zealand?
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