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Central Valley Regional Water Quality Control Board <br />8 January 2014 <br />Background Water Quality <br />Central Valley Water Board staff recognize that upgradient groundwater contains significant <br />quantities of nitrogen, and believe that these background concentrations could be affecting the <br />water quality beneath the Koppel Stockton Terminal. Koppel Stockton should provide a <br />substantiated proposal for defining a background concentration of nitrogen in shallow <br />groundwater. When Central Valley Water Board staff and Koppel Stockton Terminal agree on <br />an appropriate background concentration, Central Valley Water Board staff can reconsider the <br />closure request for these parcels. <br />California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br />Board) staff reviewed the following documents prepared by CH2M Hill. <br />• October 2013 Request for No Further Action for Portions of the Koppel Stockton Terminal <br />(NFA Request) <br />• November 2013 2013 Annual Groundwater Monitoring Report (Annual Report) <br />The Koppel Stockton Terminal comprises 4 parcels on 11.3 acres. Since 2000, phyto­ <br />remediation has been employed on about 80% of the site to remove nitrate and ammonium from <br />soil and groundwater. The NFA Request identifies that one parcel, the bagging plant parcel, is <br />undergoing additional investigation and treatment for nitrogen, while the remaining three parcels <br />are proposed for no further action. <br />REVIEW OF NO FURTHER ACTION REQUEST AND 2013 ANNUAL REPORT, KOPPEL <br />STOCKTON TERMINAL, 2025 WEST HAZELTON AVE., STOCKTON, SAN JOAQUIN <br />COUNTY <br />The two westernmost parcels proposed for no further action (APN 145-030-06 and -07) do not <br />currently meet the closure requirement. While the concentration of nitrogen in soil has declined <br />remarkably from 900 mg/kg nitrogen to the cleanup objective of 200 mg/kg or less, the <br />groundwater does not yet meet the cleanup goals. Nitrogen concentrations in shallow <br />groundwater beneath these western parcels has declined from a high of 800 mg/L to a current <br />high of 300 mg/L. The cleanup criteria for nitrogen in groundwater is the water quality objective <br />of 10 mg/L, or background, whichever is greater. The results of the additional investigation and <br />remediation in the bagging plant may reveal strategies that Koppel could employ to accelerate <br />the remediation in the western parcels. <br />Abe Northup <br />CH2M HILL <br />8067 East U Ave <br />Vicksburg, Ml 49097 <br />Water Boards <br />Karl E. Longley ScD, P.E., chair | Pamela C. Creedon P.E., BCEE, executive officer <br />11020 Sun Center Drive #200, Rancho Cordova. CA 95670 | www.waterboards.ca.gov/centralvalley <br />HtCVCLbU PAHbH <br />Edmund G. Brown Jr. <br />aoveRNon <br />Matthew Rodriquez <br />® s R I a [iff H secretary for <br />J ENVIRORMeMTAL PROTeCTlOA <br />-^roTzoiT