Alark Hard Chrome
EPA #: CAD098229214
State: California(CA)
County: Riverside County
City: Riverside
Congressional District: 43
Other Names:
Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 07/27/00
Final Date: 12/01/00
Deleted Date:
Alark Hard Chrome was a plating operation located on Main Street near Poplar Street in Riverside, CA. It operated from 1971 until it was closed in 1985. In 1982, the Riverside County Health Department inspected the site and discovered soil contamination. The Alark Potentially Responsible Parties (PRPs) were ordered to investigate the full extent of contamination at the site. All plating equipment and indoor storage tanks were removed from the site when the Riverside County District Attorney Office permanently closed Alark's operations in 1985. During the 1980's, the Alark PRPs conducted investigations, and in 1986 began an unauthorized removal of soil which was stopped by the California Department of Toxic Substances Control (DTSC). In 1990, DTSC took over the site investigation, splitting their efforts into a soils component and a groundwater component. In December 2000, the Alark facility was placed on the U.S. Environmental Protection Agency's (EPA) Superfund National Priorities List.
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Contaminants and Risks
Contaminated Media:
Groundwater
Soil and Sludges
Soil and groundwater were contaminated with chromium, hexavalent chromium, other metals and TCE as a result of spills, drips and discharges of plating solutions to a sump on the premises.
Who is Involved
This is a fund-lead site. EPA is the lead agency.
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Investigation and Cleanup Activities
Site Studies
Between 1991 and 1995, DTSC installed ten groundwater monitoring wells in the vicinity of the Alark facility to monitor groundwater contaminated by chromium. In 1994, DTSC excavated and removed approximately 1,200 cubic yards of the most heavily contaminated soils from the middle of the Alark facility and closed off the site. This area was also the main source of groundwater contamination, but significant soil contamination remains on the site.
Site Studies
In 2001, EPA conducted groundwater sampling and the results were consistent with the groundwater investigation conducted by DTSC in 1995. There were still high chromium concentrations in monitoring wells closest to the site. In one well (MW-7), the groundwater sample contained 17,300 micrograms per liter (ug/L) hexavalent chromium. Chromium exceeded the State Maximum Contaminant Level (MCL) for drinking water of 50 ug/L in five of the ten wells at the site. Since 2001, EPA has been conducting a remedial investigation to determine the extent of soil and groundwater contamination at the site. The remedial investigation has been difficult due to the complex fractured bedrock geology in the area. In August 2007, EPA completed the field work for the remedial investigation with the installation of one additional monitoring well that defined the groundwater contaminant plume southeast of the site. This completed definition of the groundwater contaminant plume in all directions. The RI Report was completed in December 2009.
Site Studies
In October 2007, EPA began a Treatability Study to evaluate the effectiveness of in-situ treatment of hexavalent chromium (Cr+6) in the vadose zone and groundwater at the Alark Site. The in-situ treatment method selected uses a calcium polysulfide solution to reduce the Cr+6 to trivalent chromium (Cr+3). Cr+3 is much less toxic that Cr+6 and is also much less soluble in groundwater. Cr+3 is stable in the soil and will not convert back to Cr+6 in the normal soil environment. The Treatability Study was completed in December 2007 and a final Treatability Study Report issued in April 2009.
In 2012, EPA will begin the Feasibility Study (FS) after the completion of a data gap analysis to fill in information not collected in the RI and Treatability Study work.
Cleanup Results to Date
The site has been closed off. EPA has completed an initial remedial investigation that attempted to defined the full extent of contamination. However, additional sampling is required to fully characterize the site; this data gaps analysis was initiated in 2011 and once completed, EPA will begin looking at possible ways to clean up the soil and groundwater contamination.
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Potentially Responsible Parties
Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.
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Public Information Repositories
The most complete collection of documents
is the official EPA site file, maintained at
the following location:
Superfund Records Center
Mail Stop SFD-7C
95 Hawthorne Street, Room 403
San Francisco, CA 94105
(415) 820-4700
Enter main lobby of 75 Hawthorne street,
go to 4th floor of South Wing Annex.
The public information repositories for
the site are at the following locations:
Riverside Public Library
3581 Mission Inn Avenue
Riverside, CA 92501
(909) 826-5201
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Contacts
|
Name |
Phone Number |
Email |
Address |
| EPA Site Manager |
Rusty Harris-Bishop |
415-972-3140 |
Harris-Bishop.Rusty@epamail.epa.gov |
Mail Code SFD1
75 Hawthorne Street
San Francisco, CA 94105 |
EPA Community
Involvement Coordinator |
Dana Barton |
415-972-3087
1-800-231-3075 |
Barton.Dana@epamail.epa.gov |
Mail Code SFD63
75 Hawthorne Street
San Francisco, CA 94105 |
EPA Public Information
Center |
|
415-947-8701 |
r9.info@epa.gov |
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| State Contact |
Joe Cully |
714-484-5473 |
JCully@dtsc.ca.gov |
California Department of Toxic Substances Control
5796 Corporate Ave.
Cypress, CA 90630 |
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| Other Contacts |
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After Hours
(Emergency Response) |
US EPA |
(800) 424-8802 |
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