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C. QUALITY ASSURANCE AND QUALITY CONTROL Quality assurance and quality control was performed on all of the data reviewed for this interim preliminary health assessment. Conclusions contained in this health assessment are based on the information received by ATSDR. The accuracy of these conclusions is determined by the availability and reliability of the data. D. PHYSICAL AND OTHER HAZARDS There are no physical hazards associated with site, except those normally found at this type of manufacturing operation. PATHWAYS ANALYSES A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT) Soils (Surface Runoff) Elevated concentrations of heavy metals and VOCs were detected in on-site surface and subsurface soils (sludges) from the ponds and surface drainage area. Surface or subsurface sampling of soils from the former solvent disposal and drum storage areas was not performed; hence, it cannot be determined if those soils are contaminated. Additional on-site and off-site drainage ditch soil or sediment sampling is needed to determine if contaminants have migrated from the source area via surface water runoff. Contaminated groundwater from the site does not appear to discharge to either of the nearest surface-water bodies because they are located about three fourths of a mile from the site and because the pumping of numerous domestic and municipal wells in the area inhibits migration of contaminants toward the surface-water bodies. Groundwater The lithologies of the site and surrounding area consist of varying mixtures Of silt, sand, and clay. on-site soil borings indicate that the first 60 feet below ground level (BGL) are a mixture of loose to very dense silt and sandy silt with less clayey silt. Two extensive water-bearing units, consisting of coarse-grained units (sand and gravel) , are present beneath the site. The A aquifer is between 177-235 feet BGL, and the B aquifer is between 425-500 feet BGL. The piezometric water level data indicate that there is an upward gradient between the A and B aquifers when the A aquifer is pumping. There is no water level difference between the aquifers when active pumping is not occurring. Because of the location and pumping of numerous domestic and municipal wells in the area of the site, it is difficult to determine the natural direction of groundwater flow (personal communication, Scott Walker, 1989a) . Water level data obtained while CWS-77 municipal well was pumping indicated that most, if not all, on-site ground water is captured by this well (CRWQCB, 1987) . The direction of groundwater flow while the CWS-77 well is 7