SECTION SEVEN
Operation and Maintenance Activities
The quarterly groundwater monitoring program began in March 1994. TCE concentrations in
both areas were still above the site cleanup level of 5 mg/L in December 1999. The average total
Mn concentration in the contaminant reduction monitoring wells has decreased from
11,000 mg/L in March 1994 to 8.0 mg/L in December 1999, while the average Mn concentration
in the migration monitoring wells has generally decreased from 488.0 to 40.0 mg/L) during the
same time period. Vinyl chloride, the other contaminant with a cleanup level for the site, was
only detected above method detection limits on one occasion and was never detected above site
cleanup levels.
It is anticipated, based on the effectiveness of the AS/SVE system, that the site cleanup level of
5 mg/L for TCE concentrations will be attained for all monitoring wells in approximately 2002
(Year 7). As specified in the ROD, after this objective has been achieved the AS/SVE system
will continue to operate for an additional 3 months to ensure that the site has been remediated.
As specified in the ROD, the quarterly monitoring of groundwater will continue through 2009
(Year 15) to confirm that groundwater will not be adversely impacted by the land treatment
activities.
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Ft. Griffey Landfill 5 OU Interim RA Report
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