3 - The Bowery_PUBLIC COMMENT (SAFER)

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Case Closure Summary Site Name: Ricoh Electronics Case # 083000552T Comments regarding investigation and remediation -continued Groundwater was encountered at approximately 10 feet bgs and was found to flow to the south. Free product was detected up to 6.9 ft. In February 1988, FP recovery was initiated. On July 8, 1988 the Board issued Cleanup and Abatement Order CAO No. 88-78, requiring Ricoh to implement corrective measures and to establish waste discharge limits. In August 1988, Ricoh implemented groundwater extraction and treatment. Up to 14,000 gallons per day were discharged to the local storm drain which discharged into San Diego Creek. In September 1992, Ricoh requested cessation of groundwater remediation because free product was no longer detected in the lsopar/groundwater recovery system. In a letter dated December 15, 1992, Regional Board staff denied the request due to the continued presence of free product in some groundwater monitoring wells and the lack of consistent groundwater monitoring. The recovery system reportedly operated until July 1998, when the three USTs were removed and replaced. In July through September 1998, the three USTs were removed and replaced by one 40,OOO-galion lsopar UST. The UST area was reportedly excavated to a depth of 16 feet, approximately 100,000 gallons of groundwater from the excavation were treated and discharged, and ORC was placed in the backfill. . Due to the continued detection of elevated concentration of TPH in the groundwater, a subsurface investigation was conducted in December 2000. Five soil borings were advanced to 17 to 20 feet and three grab groundwater samples were collected. TPH was detected at a concentration of up to 1.9 mg/kg in the soil samples and up to 8,000,000 ug/I TPH was detected in the groundwater. In January 2003, two confirmatory wells were installed at the site. TPH was detected at a concentration of up to 2,100 ug/l in the groundwater. In February 2003, a 24-hour two phase extraction test was conducted. Vapor influent concentrations peaked at 1,060 ppmv after 18 hours of operation. Approximately 13.5 Ibs (2.1 gallons) of petroleum hydrocarbons were recovered. In April 2005, the TPH concentrations in the groundwater monitoring wells have reduced to 400 ug/1. As a result, Ricoh requested site closure. Final consideration of closure of the site was delayed due to the pending removal of the one remaining UST. In September 2006, the 40,000-galion UST was removed. Two soil samples were collected each from under the UST and the dispenser. TPH (C13-C28) and TPH (C29-C40) were detected at concentrations up to 360 ppm and 860 ppm, respectively. TPH (C13-C28) and TPH (C29-C40) were detected in groundwater samples collected from the excavation at concentrations up to 530 ug/l and not detected, respectively. In July 2008, six soil borings were advanced on the Ricoh and adjacent Jaydee property to depths ranging from 17 to 45 feet bgs. The results indicated TPH at a concentration of 300 and 490 ppm in soil sampled from boring B-5 at depths of 10 and 15 feet bgs, respectively. Groundwater was sampled from two of the borings at depths ranging from 35 to 45 feet bgs. No TPH or VOCs were detected in the groundwater samples. In September 2009, two groundwater monitoring wells were installed on the adjacent Jaydee property next to boring locations B-5 and B-6. Groundwater was found at approximately 13 feet bgs and groundwater flow was to the south to southwest. TPH-g and TPH-d were detected at a concentration of 190 ug/l and 660 ug/l, respectively. On May 11, 2010, Board staff notified the legal counsel and property manger representing the fee holder of the adjacent property of the pending site closure. Board staff has not received any comments in response to the May 11, 2010 letter. Based on this data, Ricoh's consultant asserts the following: • In June 2008, volatile fuel petroleum hydrocarbons were detected at a maximum concentration of 490 mg/kg in soil samples collected from the Jay Dee property indicating that the concentrations are decreasing laterally from the former UST. 3