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23 September 2008
<br /> AGE-NC Project No.07-1537
<br /> Page 5 of 8
<br /> 3.0. FINDINGS
<br /> A discussion of field and laboratory results of soil and grab groundwater samples collected from
<br /> CPT boring and pilot boring advancements are detailed below.
<br /> 3.1. STRATIGRAPHY
<br /> Generally,the soil type encountered in pilot borings MW7 through MW 11 and soil boring B5 was
<br /> dark yellow-orange brown,yellow-orange brown,tan-brown,dark brown to dark yellow-brown clay
<br /> or silty clay.Yellow-orange brown,dark yellow-orange brown,red-brown,and dark brown silt was
<br /> encountered in pilot borings MW7,MW8,MW9,MW 10 and in soil boring B5 at approximately 30
<br /> and 35 feet bsg, 25 feet bsg, 20 and 45 feet bsg, 4 feet bsg, and 25 feet bsg, respectively. Yellow-
<br /> Brown and dark yellow-orange brown silt with sand and sandy silt was encountered in pilot borings
<br /> MW7, MW9, MW 10 and MW 11 at approximately 15 and 50 feet bsg, 15 feet bsg, 25 and 40 feet
<br /> bsg,and 55,60 and 103 feet bsg,respectively.Dark yellow-orange brown and yellow-orange brown
<br /> silty sand was encountered in pilot borings MW9 and MW 11 at approximately 25 and 40 feet bsg,
<br /> and 5, 10, 15, 85 and 89 feet bsg, respectively. Dark brown organic soil was encountered in soil
<br /> boring B5 was encountered at approximately 5 feet bsg.Red-yellow brown,dark brown,red-orange
<br /> brown, tan-brown, yellow-brown, yellow-orange brown and dark yellow-brown sandy clay was
<br /> encountered in pilot boring MW11 at approximately 30, 35, 40, 45, 65, 75, 80, 90, 91, 98.50, and
<br /> 110.50 feet bsg.A dark yellow-brown and dark brown poorly graded sand was encountered in pilot
<br /> boring MW 11 at approximately 94.5, 100.5, 106, 108.5 and 110 feet bsg.A dark brown well graded
<br /> sand was encountered in pilot boring MW 11 at approximately 103 feet bsg.Boring logs are included
<br /> in Appendix C.
<br /> Based on the boring logs from this and previous investigations,geologic cross sections A-A'through
<br /> E-E' were constructed depicting the general soil profile beneath the site (Figures 3-7).
<br /> Hydrocarbon odor was detected by an AGE representative through field observations in samples
<br /> collected from pilot boring MW 11 at depths of 20,25,35,40,50, 55, 60, 65, 70, 75, 80, 85, 92,95,
<br /> 100, and 103 feet bsg. Additionally, organic vapor was detected by the OVM in soil samples
<br /> collected from pilot boring MW11 at depths of 10, 15,20,25,30,35,40,45,50,55, 60, 65,75, 80,
<br /> 85, 90,92, 95,98, 103, 108, and 110 feet bsg. OVM-detected concentrations ranged from 1.5 parts
<br /> per million volume (ppmv; MW11-15)to 2,995 ppmv (MW11-20 and MW11-25).
<br /> Advanced GeoEvironmental,Inc.
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