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The communities potentially affected by this site are
Rancho Cordova, population 61,000; Carmichael,
population 68,000, Fair Oaks, population 41,000, and
Gold River, population 9,000. The closest residence is
about 500 feet away from the site. Groundwater is used
extensively throughout the Rancho Cordova area to supply
municipal, domestic, industrial and some irrigation
water.
Public and private drinking water supply wells have been
contaminated and wells contaminated above response
levels have been closed. Aerojet continues to monitor
drinking water supplies to assure compliance with
drinking water standards. Lake Natoma and Alder Creek
are nearby and are used for recreational activities. The
American River is a drinking water source, which
receives discharges from Aerojet's facility and
groundwater treatment systems under National Pollution
Discharge Elimination System (NPDES) permits.
The Aerojet Record of Decision for the Perimeter
Groundwater OU (OU-5) was signed on February 15, 2011
including a responsiveness summary to public comments
received. The ROD selected an Interim Remedy for
Groundwater and a final cleanup for the contaminated
soil locations. The groundwater remedy will
hydraulically contain the plume areas to prevent the
spread of contamination, with additional pumping and
treating to intercept and remove highly contaminated
groundwater where possible. Within OU-5, there are 17
contaminants of concern identified although TCE, NDMA
and perchlorate are the primary contaminants as in OU-3.
In OU-5 there are four different groundwater areas and
some of them require cleanup actions in other Operable
Units to eliminate the contaminant source. The EPA is
considering this
an interim groundwater remedy until the source areas are
fully addressed. Most of the groundwater capture system
is already in place and operating as part of the initial
actions described above.
The Soil Areas remedy is to excavate or otherwise clean
the soil areas to levels protective for residential use.
Fourteen contaminants of concern were identified in the
soil areas, including metals and others that are not
issues in groundwater. The EPA recognize that there
could be difficulty in achieving the desired cleanup
levels in some of the soil areas, so the remedy includes
a combination of engineering controls (such as
intercepting soil vapor) and Institutional Controls
(limiting the land use) as necessary.
Cleanup Results to Date - Ten groundwater extraction and
treatment systems "GETs" are operating throughout the
Aerojet site. Together they removed over 20 million
gallons of contaminated groundwater each day on average.
Through the end of 2010, all the groundwater extraction
and treatment systems at Aerojet in OU-3 and OU-5 have
treated a cumulative total of 107,000 million gallons of
groundwater and removed more than 850,000 pounds of
chemical contaminants.
EPA will be accepting public comments on the plan until
June 7, 2013, and will be hosting a public meeting to
discuss the proposed plan at 7:00 p.m. on Wednesday, May
15, 2013 at Rancho Cordova City Hall in Rancho Cordova,
Calif. |
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