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Trenching on the waste management area footprint and surrounds was conducted to evaluate the limits of waste buried(T1 to T23)and provided for additional Trench soil sampling(T24 to T91). Trench locations are illustrated in Figure 2. Comments: What is meant by "... "and provided for additional Trench soil sampling (T24 to T91)?"Are trenches T24 to T91 in wastes and/or outlying wastes?Are samples collected and analyzed only "soil' samples?What about waste and waste mixed with soils? Where are the trench logs for T24 to T91?The trench log information from each location needs to be summarized onto an appropriate figure indicating whether wastes were present/absent, if wastes are present, lateral extent/thickness and the lateral extent of waste shown. Soil samples and grab groundwater samples were collected from borings and trenches. Soil samples were analyzed for CAM 17 metals, volatile organic compounds (VOCs), polychlorinated bi- phenols (PCBs), polynuclear aromatic hydrocarbon (PNA), polycyclic aromatic hydrocarbons (PAH) or semi-volatile organic compounds (SVOCs), Dioxin and Furan and Total petroleum hydrocarbons. Detections of organic compounds are summarized Comments:An adequate summary of what"soil' (were waste samples and/or soil mixed with wastes samples analyzed?) and groundwater samples were collected and analyzed was not provided. It is not clear what samples were run for what analyses and rationale for the analytical testing program was not provided. Additionally, soil sample[s] collected in the areas of waste glass have not been impacted by the operations of wastewater and glass waste handling/ burial nor has demonstrated significant residual metals concentrations. None of the detections of metals exceed hazardous waste criteria and the additional analysis of the soil for soluble metals concentrations reportedly present at the glass waste handling/burial areas have not been hazardous. A total of four shallow soil samples collected outside the waste areas (within former surface water depressions) indicated detections of PCBs. Comments: the wording suggests samples were only soil. What is meant by "demonstrated significant residual metals concentrations"? What is this statement based on? What were the ranges of metal concentrations in samples analyzed and what were they compared to? Please clarify the statement PCBs in samples outlying waste areas; is this related to another contaminant source?Typically the terms PNAs and PAHs are typically interchangeable, so it is not clear why these constituents are separately identified. Generally, tan, brown to dark brown, silts and sands were encountered between surface grade and approximately 15 feet bsg. Comment: Was glass encountered in the borings or trenches? There is no mention of glass waste in the report text. No logs are provided to assist with answering this question. Nomenclature on the tables suggest all samples were of soils and did not include wastes or wastes mixed with soils. During the investigation of the former PNA site, the majority of the trenches demonstrated minor percentages of glass. A set of trenches at the southwest boundary of the property(south cell T46, T48, T50, T58 and T59 and north cell T64, T65, T70) demonstrated a differing thickness (topology) of the potentially buried waste. The waste strata over native soil ranged from 18 inches at trench T46 to 10 feet deep at trench T58 and to 13 feet deep at trench T65. Comments: terminology such as "demonstrated" and "minor percentages of glass" are confusing and vague. What is meant by the term "demonstrated?" What are "minor percentages?" This is supposed to be a technical report. What needs to be clearly stated are what are the areas/locations of wastes? What are the types of wastes and the lateral and vertical extents? There appear to be three(?) areas at least of waste disposal discussed, two of which were the locations of waste excavation remedial action activities. This needs to be clarified in the report text. Remediation at this location involved the use of the excavator or backhoe, which trenched down to native soil beneath any waste discovered (the current soil cap was segregated) Comments: Based on information available for review, documentation was not provided to support this statement. AGE needs to provide figures, plan and cross section, indicating the extent of excavation, locations of confirmation samples, confirmation sample analytical results and daily Ninyo&Moore 1 500 E.Louise Avenue,Lathrop,San Joaquin County,California 1 104690095 1 August 11,2017 46