|
The email from the LEA requested AGE to clarify the date of the excavation stating April 16th is
<br /> a Thursday and they wanted clarification of the role of Ron Barber and L & B Environmental in
<br /> the investigation since they were not mentioned in the work plan.
<br /> This document appears to be a summary table of exploratory trenches T1 through T23 excavated
<br /> by AGE and are not individual trench logs. The total depth of excavations appears to be 5 feet bgs
<br /> for all trenches excavated.
<br /> Comments: Why were all trenches only excavated to 5 feet bgs? It appears from review of the
<br /> documents, all samples collected and analyzed from these trenches were from 5 feet bgs. Based
<br /> on the logs, trenches T1, T2, T3, T4, T7, T8, T9, T10, T11, T12 T15, T16, T17, T18, T19, T21,T22
<br /> and T23 contained glass, some only trace glass at depths shallower than 5 feet bgs, the depth
<br /> sampled. The logs also indicate other waste/contamination such as brick/steel frame, plastic,
<br /> discolored soils, iron metal and sheet metal. It is not clear what the term "cell' refers to on the log
<br /> summary and it is unlikely the width of the exploratory trenches was 25 feet (all trenches indicated
<br /> as this wide) and this is likely the trench lengths. Analytical tables provided by AGE indicate
<br /> samples collected at 5 feet bgs only from these 23 trenches. Therefore, if interpreted correctly, it
<br /> appears that the waste is shallower than the depth sampled, at approximately 2 to 4 feet bgs and
<br /> not in the 5 foot samples, the only samples that appear to be collected and analyzed.Also, did the
<br /> trench excavations extend into native soils? It is possible that wastes are present at greater
<br /> depths separated by soils if native soil was not encountered. Trenches should be excavated to
<br /> native soils, or at a minimum a certain percentage of trenches should be excavated to native soils,
<br /> depending on the WDS.
<br /> Y T
<br /> WOOF AW2, 0*
<br /> The Site Plan identified the glass manufacturing building/areas, undeveloped land to the south,
<br /> the SJ Co-Generation (power plant) to the south/southwest and former Simplot and "Oxy"
<br /> [Occidental] Chemical [Company] Property, offsite to the east.
<br /> Comments: Although documentation to accompany this figure was not available, it appears the
<br /> figure focused on potential petroleum hydrocarbon sources and contamination and to a lesser
<br /> extent waste disposal site environmental concerns (e.g., the figure identifies waste water treatment,
<br /> oil spill, closed USTs, empty oil tank and AST areas). The figure also indicates a PG&E [Pacific Gas
<br /> & Electric Company] Substation south of the building and north of the "Waste Handling Area." The
<br /> figure identifies a 1986 AST spill, 1992 AST Spill, 1996 AST Spill and locations of several former
<br /> ASTs. An area identified as "Waste Handling Area" is one of the locations of"Soil' Borings and as
<br /> previously indicated in other documents and figures reviewed, it appears that the number and
<br /> locations of soil borings in this area are inadequate to delineate the extent of wastes based on
<br /> historical aerial photographs and other background information. Monitoring wells MW1 to MW3 are
<br /> indicated as related to a diesel spill. Similar to other aerial photographs around this time period, the
<br /> areas south and southeast of the office/warehouse/storage appears to be the location of blue-gray-
<br /> white stockpiled materials, assumed to be related to glass manufacturing (although not known, the
<br /> blue color may be related to coloring the glass). It is not known whether a Phase I Environmental
<br /> Site Assessment was performed for the property; however, it seems that initially other potential
<br /> Ninyo&Moore 1 500 E.Louise Avenue,Lathrop,San Joaquin County,California 1 104690095 1 August 11,2017 29
<br />
|