The dioxin contamination of soil in Da Nang
was worse than expected, experts said at a conference reviewing the cleanup on
Tuesday.
The event,
organized by the National Steering Committee for Post-war Clearance of Ordnance
and Toxic chemicals and USAID, shared some details on dioxin cleanup at the Da
Nang International Airport, a U.S. air base during the Vietnam War.
Pham Quang
Vu, head of the Air Force and Air Defense’s Military Science Division, said
earlier calculations had underestimated the actual contamination at the
airport.
He said the
actual amount of contaminated soil is 162,500 cubic meters and not 72,900 cubic
meters as earlier estimated.
Anthony
Kolb, chief of USAID’s environmental remediation unit, explained that experts
only took soil samples from the surface and from that determined the depth to
which the dioxin could have penetrated.
The dioxin
had percolated three meters deeper than expected, he said at the conference in
Da Nang.
Vu said the
miscalculation could be attributed to the fact this was the first time this
particular technology was used to remove dioxin from the soil on such a large
scale. It involves heating the contaminated soil while covering it in concrete.
The finding
could help make future dioxin assessments more accurate, especially at another
ongoing cleanup project at the Bien Hoa Air Base in the southern province of
Dong Nai. Bien Hoa is considered one of the worst dioxin-contaminated spots,
with some 850,000 tons of soil feared contaminated.
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