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Californegional Water Quality C rol BoardOr
<br /> Central Valley Region °
<br /> Katherine Hart, Chair
<br /> 11020 Sun Center Drive,#1200,Rancho Cordova,California 95670-6114
<br /> Matthew Rodriquez (916)464-3291 •FAX(916)464-4645 Edmund G.Brown Jr.
<br /> Secretary far http://www.waterboards.ca.gov/centralvalley Governor
<br /> Environmental Protection RECEIVED
<br /> 1 February 2012 FEB 0 2 2012
<br /> Mr. Robert Jackson ENVIRONMENTAL HEALTH
<br /> Crop Production Services PERMIT/SERVICES
<br /> 3005 Rocky Mountain Avenue
<br /> Loveland, CO 80538-9001
<br /> REMEDIATION REVIEW, CROP PRODUCTION SERVICES, VERNALIS, 35100 S. HWY 33,
<br /> SAN JOAQUIN COUNTY
<br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water
<br /> Board) staff has reviewed the 1 November 2011 Second 2011 Semi-Annual Groundwater
<br /> Monitoring and Sampling Report (Monitoring Report) prepared by ATC Associates for the Crop
<br /> Production Services Branch #0501 in Vernalis (CPS). The Monitoring Report describes
<br /> groundwater conditions and presents groundwater data that tracks the performance of a pilot-
<br /> scale remediation. Based on the results, Central Valley Water Board staff request that CPS
<br /> prepare a remedial action plan.
<br /> Pilot Study
<br /> The in-situ groundwater amendment, Hydrogen Releasing Compound (HRC), was injected at
<br /> the former evaporation pond in 2002 to remove ammonium, nitrate, 1,2-dichloropropane (1,2-
<br /> DCP), and 1,2,3-trichloropropane (1,2,3-TCP). In 2003, reductions of nitrate, ammonium, and
<br /> 1,2-DCP were observed in MW-2, the proximate downgradient monitoring well. These
<br /> reductions occurred concurrently with an increase in dissolved organic carbon and geochemical
<br /> changes indicative of biological activity, such as production of methane, carbon dioxide, and
<br /> dissolved manganese. As documented in the 20 April 2007 Pilot Study Assessment Report by
<br /> Geosyntec Consultants, these changes were observed between five and 12 months after the
<br /> 2002 injection. In 2007, a longer-acting substance, HRC-X, was applied in an expanded
<br /> treatment area.
<br /> In the Monitoring Report, the biogeochemical monitoring shows that within the first two years of
<br /> the HRC-X injection, ammonium was degraded and biological activity was vigorous in the
<br /> injection area and in downgradient monitoring well MW-7. Biological activity and ammonium
<br /> degradation, however, was not apparent in MW-2. In 2011, even though some dissolved
<br /> organic carbon remains, biological activity does not seem to be occurring.
<br /> Groundwater Quality
<br /> Groundwater quality beneath the former evaporation pond, as measured in MW-6R, is
<br /> comparable to groundwater downgradient of the pond, as measured in MW-2. Both contain
<br /> ammonium at approximately 180 mg/L, along with 1,2,3-trichloropropane at approximately 0.5
<br /> ug/L, 1,2-dichloropropane between 2.9 and 8.8 ug/L, and diuron between 15 and 19 ug/L.
<br /> California Environmental Protection Agency
<br /> (a Recycled Paper
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