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May
2006 through January 2007
Mr. Mantegani used
his 0.6-acre property in South San Francisco,
California as a nursery from the late 1930s through
the late 1980s, in which pesticides DDT, DDE,
chlordane, Endosulfan II and Dieldrin was used
to control pests. Elevated
concentrations of DDT (up to 9 ppm) and Dieldrin
(up to 1 ppm) were detected in the surface soil
during subsequent Phase II ESAs. Mr. Mantegani,
at the recommendation of the DTSC, contracted with BioTech
Restorations to destroy the residual
pesticides within the subsurface soil at his property. A
RAW was prepared and approved by the DTSC in April
2006 and in May 2006, approximately 4,000 pounds
of Factor, lime and soil amendments were mixed
into the soil and irrigated. Mr. Mantegani
oversaw the bi-weekly irrigation of his property
and BioTech managed the soil mixing operations,
which occurred every 10 days. Within 3 weeks
of initial Factor application, DDT and DDE concentrations
were reduced from approximately 9 ppm to less than
0.5 ppm and Dieldrin was reduced from approximately
1 ppm to 0.5 ppm. Multiple applications of
lime were necessary due to the acidic nature of
the soil from June through September 2006. By
December 2006, Dieldrin was reduced to approximately
0.1 ppm and the site was formally closed by the
DTSC in their Closure Letter dated February 20,
2007. The Mantegani Property was the first BioTech
Restorations project in which Factor
was used to treat a mixture of four different organochloride
pesticides in soil to residential standards.
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