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* MEMORANDUM e CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD • CENTRAL VALLEY REGION 3443 Routier Road, Suite A Phone: (916) 255-3000 Sacramento, CA 95827-3098 CALNET: 8494-3000 TO: 1905 N. Broadway file FROM: Wendy Wyels Ag Unit DATE: 5 March 1997 SIGNATURE: Q'AAA)j urtJ,`r�/� SUBJECT: SUMMARY OF THE SITE CHARACTERIZATION AND REMEDIATION ACTIVITIES ACCOMPLISHED TO DATE I have reviewed the Regional Board files and reports pertaining to the environmental work at the former PureGro/Brea Ag facility at 1905 N. Broadway, Stockton. A year-by-year summary is given. I have summarized the analytical results from the sampling events which may not be common knowledge and/or have a bearing on staff's request for additional characterization. 1. 1981: Union Oil Company analyzed the sludge from the Brea Ag pond. Nitrogen concentrations ranged from 34,000 mg/kg to 95,000 mg/kg. 2. 1985: Brea Ag collected soil samples from four locations within the PureGro portion of the facility. The soil south of the mix plant/tank farm contained ethion, endosulfan, DDE, and DBCP. The soil west of the fumigant area had diuron, linuron, endosulfan, DDE, DDT, endrin aldehyde, and endosulfan sulfate. All concentrations were less than 1 mg/kg. 3. 1987: 1,2-DCP contamination found in nearby California Water Service wells. PureGro/Brea facility was briefly investigated by the Board. Because the Brea well did not contain 1,2-DCP, the investigation ceased. 4. 1989: Kleinfelder removed an underground tank. (I don't have this report). 5. 1990: during the construction of the new tank farm, an abandoned oil-water separator and three dry wells were found. Soil samples were taken from a test pit, and were found to contain 1,2- DCP and TPH. 6. 1991: (a) Soil samples were collected from three borings located between the dry wells. The borings extended to 51' bgs. The soil contained 1,2-DCP, nitrate, nitrite, TKN, DDT, DDE, and DDD. (b) In the next phase of work, two deeper borings (to 80' and 90' bgs) were drilled near the original three. Again, 1,2-DCP and nitrate were found in most of the soil samples. Groundwater samples were collected from these two borings. 1,2-DCP was found at 27 and 8.8 µg/1, while nitrate was found at 12-20 mg/l. (c) Approximately 15 cubic yards of DDT- contaminated soil was excavated to a depth of 12 feet from the oil-water separator area. (d) An additional 290 cubic yards of TPH-contaminated soil was excavated to a depth of 24 feet from the oil-water separator area. 7. 1992: Seven soil borings were drilled around the new tank farm. Soil samples were taken above and below the estimated depth of maximum high groundwater. Nitrate concentrations ranged from 0.1 mg/kg to 278 mg/kg. 1,2-DCP was not detected.