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EDMUND G. BROWN.JR.
<br /> OOvlRNOR
<br /> C L 11 0 R M I♦ RECEIVED MATTHEW RODRIOUEZ
<br /> SECRETARY FOR
<br /> WaterBoards E-RONMENTAL PROTECTIOi,
<br /> MAR 13 2014
<br /> Central Valley Regional Water Quality Control Board
<br /> M IONMENTAL HEALTH
<br /> 11 March 2014
<br /> Mr. Brian Duggan
<br /> Environmental Manager
<br /> Crop Production Services, Inc.
<br /> 3005 Rocky Mountain Ave.
<br /> Loveland, Colorado 80538-9001
<br /> CONCEPTUAL SITE MODEL REVIEW, CROP PRODUCTION SERVICES, VERNALIS,
<br /> 35100 S. HIGHWAY 33, SAN JOAQUIN COUNTY
<br /> The Crop Production Services (CPS) facility in Vernalis has been a retail agricultural chemical
<br /> distribution facility under several different owners since 1969. California Regional Water Quality
<br /> Control Board, Central Valley Region (Central Valley Water Board) has reviewed the 18 June
<br /> 2013 Conceptual Site Model, prepared by Rubik Environmental. The Conceptual Site Model
<br /> contains soil data obtained since 1990, groundwater data obtained since 1996, a summary of
<br /> insitu remediation efforts, associated biogeochemistry data, boring logs and stratigraphic cross
<br /> sections. The contaminants of concern at this facility include nitrate, ammonium, 1,2-dichloro-
<br /> propane (1,2-DCP), and 1,2,3-trichloropropane (1,2,3-TCP).
<br /> Revisions to Table 5
<br /> In the Conceptual Site Model, Table 5 presents historical soil sampling data. The table,
<br /> however, did not contain a complete accounting of soil samples obtained in 1990, and was
<br /> missing some of the carbamate/urea compounds detected in 1990 and 1993. In a 13 February
<br /> 2014 telephone conversation, Ms. Morgan Saltsgiver of Rubik Environmental shared that Rubik
<br /> did not have the complete report with the 1990 data. This report has now been uploaded to
<br /> Geotracker. On 11 March 2014, Ms. Saltsgiver provided a revised Table 5 and uploaded the
<br /> Conceptual Site Model with the corrected Table 5 to Geotracker.
<br /> Remediation Results
<br /> Insitu bioremediation was conducted at the former evaporation pond in 2002 by injecting
<br /> Hydrogen Releasing Compound® (HRC) into shallow groundwater. In 2007, HRC-X, which is
<br /> formulated to provide a longer release period, was injected into groundwater in a larger area of
<br /> the former evaporation pond and downgradient of the facility. The constituent concentrations
<br /> suggest that both HRC injections were effective at reducing the concentration of nitrogen,
<br /> 1,2-DCP, 1,2,3-TCP, and possibly ammonium.
<br /> Following the 2002 HRC injection, nitrate (as nitrogen) concentration decreased in MW-2, which
<br /> is about 5 feet downgradient, from about 60 mg/I to about 5 mg/L within 6 months of the
<br /> injection, 1,2,3-TCP decreased from about 7 ug/L to about 0.3 ug/L within 3 years, and 1,2-DCP
<br /> decreased from about 38 ug/L to about 8 ug/L within 4 years of injection. Four years following
<br /> the 2007 HRC-X injection, nitrate (as nitrogen) decreased in MW-7, which is about 15 feet
<br /> KARL E. LONGLEY SCD, P.E., CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER
<br /> 11020 Sun Center Drive 4200,Rancho Cordova,CA 95670 1 www.waterboards.ca.gov/centralvalley
<br /> 4„O Ht CYCL---
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