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08 September 2000 <br />AGE -NC Project No. 97-0372 <br />Page 7 of 18 <br />chemical storage in the area are not known to AGE, but probably included materials for the water <br />treatment system, metals solutions and corrosives for the plating processes. Chemicals of potential <br />concern include the metals cobalt, copper, nickel, lead and tin. Locally, high or low pH conditions <br />may be a concern. <br />2.4.4. Material Preparation Room <br />North of the eastern plating room is a material preparation room. A large area of concrete is oil - <br />stained from a piece of machinery. A concrete -filled abandoned floor drain is in the area. Material <br />preparation activities are not currently known to AGE, but may have included cutting and etching <br />of materials. Potential contaminants of concern would include metals and corrosive pH disposed <br />down the drain. <br />2.4.5. Miscellaneous and Tank Storage Areas <br />The asphalt -paved area east of the building was utilized for above -ground tank storage of treated <br />waste water. A release of untreated, or contaminated water from a polyvinyl tank in the driveway <br />near the building resulted in excavation of soil. An oval area approximately 8 feet wide and 42 feet <br />long was excavated, as shown on Figure 2. There is a shallow pit or open boring in the area that was <br />a shallow sump for the release valve on the poly tank. The shallow pit is also shown on Figure 2. <br />2.5. PREVIOUS INVESTIGATIONS <br />On 25 September 1997, at the request of Mr. John Hinkel, AGE advanced eight soil boring on the <br />site to assess soil samples for pH, chromium, copper and zinc. Four borings were advanced in the <br />eastern portion of the plating bath area and four borings were advanced in the treatment/chemical <br />storage area, as shown on Figure 3. Soil samples were collected from depths of 2 feet and 5 feet <br />below surface grade (bsg) in each of the eight borings. The borings were reentered on 24 May 1999 <br />to collect additional soil samples at approximately 6 feet bsg for analysis for lead. The borings were <br />advanced by hand-augering through holes cut in the concrete -flooring. The samples were collected <br />utilizing a hammer -driven metric soil sampler loaded with pre -cleaned brass sleeves. The samples <br />were properly preserved and shipped to a California Department of Health Services (DHS) -certified <br />analytical laboratory under chain -of -custody. The results of the analysis are presented in Table 1. <br />The pH of the soil samples ranged from 6.7 to 9.0 except for two samples from boring B7, which <br />had pH values of 4.5 and 3.6 at 2 feet bsg and 5 feet bsg, respectively. Chromium concentrations <br />ranged from 18 milligrams per kilogram (mg/kg) to 69 mg/kg. Copper concentrations ranged from <br />Advanced GeoEnvironmental, Inc <br />