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1 . SCOPE AND PURPOSE This investigation was conducted to determine the possible pres- ence and extent of contamination of soil or groundwater, which may have resulted from previous industrial activities on the site, occupied most recently by Shinko Electric America (Shinko) . The principal concern was for cyanide and priority metals, used in electroplating operations which took place during the 1980s (see Section 2) . Potential organic contamination was also inves- tigated, chiefly concerning site activities previous to Shinko' s . The scope of the present investigation was as follows : provide advice on selection of soil boring locations (based in part on a determination of groundwater flow direction) , drill and log six ' borings, package soil and groundwater samples for analysis, and finally to draw conclusions concerning possible chemical contami- nation. ' Chemical analyses performed included priority metals, cyanide, volatile organics, semi-volatile organics, chlorinated pesticides and PCBs, and total oil and grease . rFigure 1 shows the location of the Shinko Electric America site in Manteca, and Figure 2 shows locations of the six soil borings with respect to the eastern portion of the plant building and chemical storage/waste treatment vaults . Field work was conducted on October 20 and 21, 1994 . 2 . BACKGROUND -- SITE HISTORY The plant building at this site was constructed in 1977 and occupied initially by Moduline, a builder of mobile homes, for a t period of five years . In 1982 , the building was sold to Shinko Electric America (Shinko) , which manufactured computer components there until March 1990 . Shinko produced micro-thin metal compon- ents, called lead frames, and this involved metal stamping, electroplating (copper, silver, gold) , cutting and packaging, and waste water treatment (WWT) . Shinko constructed the WWT facility (WWTF) in 1982 . After cessation of operations, the WWTF was left in place as a potential asset to future industrial owners; howev- er, the WWTF has since been entirely removed. The Shinko operations utilized bulk chemicals, stored in the vault of Area 11, including acids, caustics, and cyanide, and generated several types of hazardous waste . Wastes included ' acid, caustic, and cyanide solutions, which were stored in the vault of Area 10 . These wastes were pre-treated in the WWTF area (Area 10 and between this area and the building) . The WWTF included some 34 tanks with volumes ranging from 450 to 25, 000 gallons . Equipment included units for cyanide destruc- t 1