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the wastes, and underlying the wastes in native soils to confirm underlying soils are not impacted. <br /> Taking samples at the same depths in exploratory trenches regardless of subsurface conditions <br /> encountered does not adequately characterize the wastes. Trench logs were not included in the <br /> submittal so an evaluation of whether samples analyzed were wastes or soils, or both is not <br /> known. This information needs to be provided. Based only on reviewing the tables, it appears that <br /> analytical data is minimal for trenches T24 through T91 (not adequately described in summary <br /> document text), with no analytical data from most of these exploratory trenches. <br /> Generally, tan, brown to dark brown, silts and sands were encountered from the surface to <br /> approximately 15 feet bgs. Comment: There is no information in the report text about the locations <br /> and extents of wastes encountered based on the site investigations. Was glass encountered or <br /> other wastes? (no trench logs provided). <br /> Soil samples and grab groundwater samples were collected from borings and trenches. Soil <br /> samples were analyzed for CAM 17 metals, volatile organic compounds (VOCs), polychlorinated <br /> bi-phenols (PCBs), polynuclear aromatic hydrocarbon (PNA), polycyclic aromatic hydrocarbons <br /> (PAH) or semi-volatile organic compounds (SVOCs), dioxin[s] and furan[s] and total petroleum <br /> hydrocarbons (TPH). "Detections of organic compounds were summarized."Comment: A concise <br /> and complete summary of the analytical data needs to be provided in the report text. Were <br /> samples analyzed soils, soils and wastes or wastes or?The report only says "soil' samples were <br /> collected and analyzed which could be interpreted to mean that no waste samples were collected <br /> and analyzed. Trench logs are missing from this submittal. What is meant by "Detections of <br /> organic compounds were summarized"?Also, in the summary document, what is the origin of the <br /> table following Table 4? <br /> The majority of the water samples have demonstrated no direct impact to the water quality or no <br /> significant impact to the shallow groundwater. Comment: why is water quality in general separate <br /> from shallow groundwater quality? Trench T64 water sample was collected within the north waste <br /> glass cell as illustrated in Figure 2, and initially "demonstrated"minor concentrations of petroleum <br /> hydrocarbons (TPH-diesel) present in the shallow groundwater, below buried waste. Comment: <br /> the report does not indicate the locations, types, thicknesses of wastes and trench logs were not <br /> available for review. Subsequent grab groundwater samples collected within the base of the same <br /> waste glass cell(north excavation area) did not have any detections of petroleum hydrocarbons. <br /> Additionally, soil samples collected in the former glass management area demonstrated that the <br /> area was not adversely impacted by the operations of glass waste handling/burial, nor have the <br /> soil samples collected demonstrated significant residual metals concentrations. None of the <br /> metals concentrations (TTLC — Total Threshold Limit Concentration) detected exceed hazardous <br /> waste criteria that the area was not adversely impacted by the operations of glass waste <br /> handling/burial, nor have the soil samples collected demonstrated significant residual metals <br /> concentrations. None of the metals concentrations (TTLC— Total Threshold Limit Concentration) <br /> detected exceed hazardous waste criteria. Comment: Are the samples of soils, or soils and <br /> wastes, or wastes? All tables indicate samples are of "soils" only. AB designated samples were <br /> collected from depths of 5 and 10 feet bgs from borings or at 18 inches bgs. At trenches T1 <br /> through T23, samples were only collected at 5 feet bgs, regardless of subsurface conditions and <br /> field observations. Where is the analytical data for the other trenches, T24 to T91? Only some <br /> samples appear to have been collected and analyzed and it is not clear what the rationale was for <br /> what samples were collected and analyzed? Table 2 suggests additional trenches (e.g., T7B, <br /> T10B, T11 B, in the area of previous trenches? these suspected additional and likely deeper <br /> trenches are not discussed in the report. There appears to be very little analytical data for the <br /> additional 68 trenches(T24 to T91) based on reviewing the summary tables. <br /> Ninyo&Moore 1 500 E.Louise Avenue,Lathrop,San Joaquin County,California 1 104690095 1 August 11,2017 50 <br />