SITE INFORMATION AND CORRESPONDENCE

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Inspection Report -2- 12 October 1989 Kearney-KPF Stockton, San Joaquin County of the dry well. Three five-foot deep trenches were dug in the area. Hargis was unable to confirm the location of a dry well east of the foundry. I discussed Phase II of the Hargis remedial investigation with Terry Turner. This phase will consist of drilling off-site and performing additional aquifer tests. Additional data are needed from aquifer tests of the intermediate and deep zones. However, the intermediate zone contains high concentrations of VOCs. Because on-site disposal in the western field is only allowed for aquifer test waters below drinking water standards, the facility is caught between needing the data for remediation and causing a disposal problem by generating the data. The facility is not connected to the city sewer line, on-site water storage is limited and previous aquifer test water disposal costs have reportedly been high. I observed the condition of the three disposal areas (cuttings, drilling mud and development and aquifer test waters) in the field in the western portion of the site. The three areas had been thoroughly disced and were dry. However, the drilling mud disposal area was clearly visible and could easily be delineated because the disced dry mud was a light tan compared to the surrounding brown native soils. I dug down approximately six inches through the disced mud in several areas. The native soils which were below the extent of the discs were dark brown, and dense, and could easily be differentiated from the overlying material . It appears that the volume of mud from Phase I of the Hargis remedial investigation which was disposed of to this area was excessive so that the upper six inches of material is no longer representative of or similar to the surrounding native soils. Because of the high clay content from the mud in the upper six inches of soil , it is anticipated that infiltration and drying conditions from the winter rains may be dissimilar to that of the surrounding area. INSPECTION SUMMARY: The soil assessment will be completed and data evaluation for the pond closure alternative is scheduled to begin by 20 November 1989. Hargis will submit the Selected Closure Alternative Documentation (which will include the results of the soil assessment) by 19 January 1990. Hargis is also scheduled to submit a Report of Waste Discharge by this date. Pond .closure is scheduled to begin by 1 June 1990 and should be completed by 1 December 1990. Because total VOC concentrations in the intermediate zone run as high as approximately 2,500 micrograms per liter (ppb) , Kearney-KPF must not dispose of these aquifer test waters in the western field. Kearney must consider other disposal options such as using on-site storage and hauling to the headworks of the sewer or using a temporary line to the nearest sewer line using a slow bleed rate. The facility should also consider using an on-site treatment system, such as aerating the water through sprinklers, prior to disposal of the aquifer test waters in the western field. However, if this alternative is selected, pilot tests would need to be performed to demonstrate that concentrations could be lowered to acceptable levels. Because Phase II of the Hargis remedial investigation includes the installation of additional monitoring wells, more drilling mud will be disposed of in the field. This additional mud would be disced with predominately dried drilling mud and not with native soils. Therefore, the placement of additional mud to this disposal area should