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Mr. Duncan A. Austin - 2 - 30 May 2014 <br /> Actions: Investigation began in 1989, and extensive soil sampling occurred in 1995. <br /> • Groundwater monitoring began in 1996. <br /> • In 1998, poplar trees were planted for a pilot-scale study of phytoremediation in the <br /> southwest parcel. <br /> • In 2000, most of the 11.3-acre site, including the stormwater parcel, was planted with <br /> poplars for full-scale phytoremediation. <br /> • Between 2002 and 2013, trees have regularly been replanted as needed. <br /> • In February 2014, stormwater pond monitoring wells KP-4 and KP-4D were destroyed. <br /> Extent defined: The extent of pollution has been defined. <br /> Estimated Residual Concentration: The stormwater pond parcel meets the cleanup goals of <br /> less than 200 mg/kg nitrogen in soil, and less than 10 mg/L nitrate in groundwater. <br /> Threat to Groundwater: The soil in the stormwater parce I contains up to 98 mg/kg nitrate-N, <br /> which is not anticipated to degrade groundwater. <br /> Threat to Human Health: <br /> • Vapor Intrusion Hazard: There are no vapor intrusion issues at this concentration of <br /> nitrate. <br /> • Dermal Contact Hazard: There is not a dermal contact hazard. <br /> Public Review: A 30-day public comment period began 8 April 2014. No comments had been <br /> received by 14 May 2014. <br /> Summary: Based on the above evaluations, the Central Valley Water Board staff concurs with <br /> Koppel Stockton Terminal that the stormwater pond parcel of APN 145-090-48 does not <br /> appear to present either a threat to water quality, human health, or the biota. <br />