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Mr. Kevin Bertrand -2- 15 May 2020
<br /> comprised of 42 borings and 4,032 pounds of HRC-X,a slow release version of HRC.
<br /> The HRC and HRC-X injections appear to have been effective,as concentrations of
<br /> Water Boards nitrate, 1,2,3-TCP, and 1,2-DCP have declined and generally leveled off near or below
<br /> their respective primary Maximum Contaminant Levels(MCLs).
<br /> Central Valley Regional Water Quality Control Board
<br /> Nutrien has been monitoring groundwater conditions at the site under
<br /> MRP R5-2007-0825(the MRP)and has been monitoring some locations since 1996.
<br /> 15 May 2020 Nutrien believes this site is worthy of closure. Some monitoring wells have been dry
<br /> since 2016 due to receding groundwater levels. Nutrien has elected to replace the well
<br /> network with deeper monitoring well in hopes that current groundwater conditions below
<br /> Mr. Kevin Bertrand the dry wells support site closure.
<br /> Senior Environmental Remediation Manager
<br /> Nutrlen Ag Solutions, Inc. Proposed Work
<br /> 5296 Harvest Lake Dr.
<br /> Loveland,CO 80538 The Workplan proposes to:
<br /> 1. Destroy all eight existing monitoring wells, including: MW-1, MWL2, MW-3, MW4,
<br /> WELL NETWORK REPLACEMENT CONCURRENCE, NUTRIEN AS SOLUTIONS, MW-5, MW-6R, MW-7, and MW-8.All existing monitoring wells are installed to
<br /> 35100 SOUTH HIGHWAY 33,VERNALIS,SAN JOAQUIN COUNTY between 45 and 50 feet bgs. These wells will be overdrilled by 2 feet using a
<br /> hollow-stem auger and sealed using neat cement and sand.
<br /> Staff of the Central Valley Regional Water Quality Control Board (Regional Board)have
<br /> reviewed the 8 May 2020, Monitoring Well Network Replacement Work Plan(Workplan) 2. Install five new monitoring wells:MW-21R, MW-3R, MW-4R, MW-5R, and MW-BR
<br /> submitted on your behalf by Rubik Environmental Inc., for the property located at 35100 at the existing locations of MW-2, MW-3, MW4, MW-5 and MW-8.The new wells
<br /> South Highway 33 in Vemalis, California (the Site). Nutrient submitted the Workplan in will be installed to 65 feet bgs with the bottom 20 feet being screened.
<br /> response to a discussion between Nutrien, Rubik and Regional Board staff during an 8
<br /> April 2020 project review phone call. Nutrien has been Weaning up and monitoring a 3. Forgo replacing MW-1,since it is no longer monitored in accordance with the
<br /> release of 1,2,3-Trichloropropane, 1,2-Dichloropropene, and nitrate at the site and MRP.
<br /> would like to document site groundwater conditions in support of a request for closure.
<br /> 4. Forgo replacing MW6R and MW-7,since they are less than 50 feet the
<br /> Background proposed MW-2R location. MW-2R will provide representative data for MW-6R
<br /> The Site is a 6-acre agricultural chemical retail facility that has been in operation since
<br /> and MWF7.
<br /> 1969.The site operates as a distribution and retail center for bulk dry and liquid 5. Sample the replacement wells during subsequent monitoring and sampling
<br /> fertilizer, and pre-packed fertilizer and pesticides.Site assessments indicated that the events following installation,and include analytical results in the semi-annual
<br /> nitrate concentrations were highest in the historic tank farm, while the chlorinated monitoring report.
<br /> hydrocarbon concentrations were highest near the stormwater evaporation pond.
<br /> Assessment and remediation has been ongoing since the 1980s. In the late 1980s, Comments
<br /> underground storage tanks were removed and impacted soil was aerated on site and
<br /> later disposed to a landfill offsite. In 1999 and 2000,approximately 48,000 gallons of Regional Board staff has the following comments:
<br /> groundwater were extracted. However, groundwater extraction was determined to be
<br /> infeasible due to electrical conductivity exceedances of Waste Discharge Requirements 1. As directed under the MRP,the new monitoring wells shall be monitored for
<br /> for discharging the extracted water to an irigation canal. In 2002, a pilot test was Water Level,Total Organic Nitrogen,Total Ammonia as Nitrogen,Volatile
<br /> conducted util'Izing 3,360 pounds of Hydrogen Release Compound(HRC)injections for Organic compounds including 1,2-Dichloropropane, 1,2,3-Trichloropropane, 1,2-
<br /> enhanced in-situ treatment of the chlorinated hydrocarbons and nitrate in 28 locations in Dibromo-3-Chloropropane, 1,2-Dibromoethane, and Carbamate/Urea Pesticides.
<br /> the former evaporation pond. In 2007,two expanded pilot tests were conducted, each
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