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of wastes encountered (e.g., burned wastes, glass and other debris, estimated percentages of <br /> soils mixed with wastes) based on logs and other field observations; locations and thicknesses of <br /> wastes; and include a figure indicating the lateral extent of wastes with information about the <br /> presence or absence of wastes and thicknesses, as applicable at each boring and trench location. <br /> Tables also are typically prepared summarizing the results. It appears that a figure indicating the <br /> presence or absence of wastes and waste thicknesses when encountered was provided at a later <br /> time; however, trenches T75, T78, T88, T92,T93,T94, T95, T96, T97, T98 and T99 were missing <br /> from the figure.Trench logs need to accompany the report as supporting documentation. <br /> • Inconsistent and confusing terminology makes it additionally difficult to understand the two general <br /> areas of waste disposal that were evaluated (see last comment in this section). <br /> • In summary, based on available information, it does not appear that wastes were adequately <br /> characterized and there is not enough information presented to confirm that wastes were <br /> adequately delineated. It is not clear whether exploratory borings and trenches extended to <br /> native soils (vertical delineation of wastes), 86 trench logs were not available for review and <br /> the lateral of extent of wastes based on investigations has not been adequately described or <br /> indicated on a figure. <br /> Preliminary Site Assessment(PSA) Reports <br /> • The PSA reports reviewed were incomplete. A PSA report should at a minimum include <br /> information on field methodologies, rationale for locations of borings and trenches, a summary of <br /> the analytical testing program and concise summaries of analytical results in tabulated format with <br /> comparison to applicable and appropriate screening and/or regulatory and/or hazardous waste <br /> levels depending on the planned future uses of the WDS, boring and trench logs, summary and <br /> conclusions based on the investigation and other information. A figure needs to accompany the <br /> PSA report indicating locations of all borings and trenches, and at each location whether wastes <br /> were encountered, and if so, the waste depths and thicknesses. Based on this, combined with <br /> historical aerial photographs, geophysical survey, field observations and any other background <br /> information, an estimated lateral extent of wastes needs to be shown on the figure. Based on <br /> waste depths in the boring(s) and trenches, and the estimated lateral extent, an estimate of the <br /> volume of wastes needs to be provided. Cross sections, photographs, air monitoring, field <br /> documentation and other background data are commonly included in these reports. <br /> • The recommendations section in the PSA reports that soil and groundwater at the site appears to <br /> be adequately assessed and more specifically the statement that the site is not negatively <br /> impacted by historical usage is not supported based on available background information, <br /> because the work conducted was limited in nature and did not include an extensive enough <br /> investigation to make such a statement, the lateral and vertical extent of wastes does not appear <br /> to have been adequately characterized and delineated, and the presentation of data in the PSA <br /> report was not sufficient to make such statements. Several other reasons this statement is not <br /> supported are that the wastes that were excavated were disposed of at a Class II landfill <br /> suggesting they were not likely accepted at a Class III landfill based on analytical data and/or <br /> generator site use. Documentation from the 1980s indicated that wastes generated during glass <br /> manufacturing processes were required to be disposed of at a Class I landfill. More specifically, a <br /> letter from the California Regional Water Quality Control Board-Central Valley Region, (Water <br /> Board)to Libbey-Owens Ford Glass, as far back as May 3, 1982, stated that based on their review <br /> of the analytical data for the baghouse dust proposed to be disposed of at the Forward, Inc. "Class <br /> II-1 landfill'that due to the caustic nature (pH of 11.5) and high selenium concentration (350 times <br /> the California Assessment Manual [CAM] hazardous level), this material was not suitable for <br /> disposal at the Forward Landfill (Class II landfill). <br /> Ninyo&Moore 1 500 E.Louise Avenue,Lathrop,San Joaquin County,California 1 104690095 1 August 11,2017 <br />