URS Corporation 

Barley Mill Plaza, Building 19 

4417 Lancaster Pike 

Wilmington, Delaware 19805 

DuPont Marshall Laboratory PFOA 

Sampling Results – December 2007 and 

January 2008 

Date: July 2009 Project No.: 18985591.07003 
DuPont Marshall Laboratory PFOA Sampling Results – 

December 2007 and January 2008 Table of Contents

Marshall Labs PFOA Sampling Results_12-07 and 01-08.doc i 

Wilmington, DE

Table of Contents 

1.0 DuPont Marshall Laboratory PFOA Sampling Results – December 2007 and 

January 2008 ...............................................................................................................1 

Tables 

Table 1 Summary of PFOA Soil Analytical Results 

Table 2 Summary of PFOA Groundwater Analytical Results 

Figure 

Figure 1 PFOA Sample Locations 
DuPont Marshall Laboratory PFOA Sampling Results – 

DuPont Marshall Laboratory PFOA 

Sampling Results – December 2007 and 

December 2007 and January 2008 January 2008

Marshall Labs PFOA Sampling Results_12-07 and 01-08.doc 1 

Wilmington, DE

1.0 DuPont Marshall Laboratory PFOA Sampling Results – 

December 2007 and January 2008 

In December 2007 and January 2008, DuPont completed site characterization activities at 

the DuPont Marshall Laboratory facility in Philadelphia, Pennsylvania. In conjunction 

with these activities, DuPont investigated the subsurface soil and groundwater at the site 

for the presence of Perfluorooctanoic Acid (PFOA). 

A total of six soil borings were advanced using a Geoprobe Macro-Core Soil Sampling 

system (1.5-inch ID) in the area of the former Teflon processing & handling area. The 

locations of the soil borings are shown on Figure 1. Soil was transferred from the 

sampling device to a Pyrex mixing bowl for homogenization. Soil samples were then 

transferred to sample collection bottles (supplied by the laboratory) using Pyrex spoons 

or trowels. The soil samples were shipped to Test America of Denver, Colorado and 

analyzed for PFOA. The analytical results of the soil sampling are presented on Table 1. 

A total of 9 temporary piezometers were installed to intersect the shallow groundwater 

system at various locations to determine groundwater quality at the site. The locations of 

the piezometers are shown on Figure 1. Each piezometer was installed using Geoprobe®

Direct Push method. The piezometers were constructed using 1-inch diameter schedule 

40 polyvinyl chloride (PVC) pipe and 10-slot (0.010-inch) screen, which was advanced 

into the saturated zone. The piezometers were allowed to sit for at least 24 hours to 

naturally develop. 

Groundwater samples were collected from the temporary piezometers using a peristaltic 

pump. Following sampling, the temporary wells were properly abandoned and 

permanently sealed using cement-bentonite. The groundwater samples were shipped to 

Test America and analyzed for PFOA. The analytical results of the groundwater 

sampling are presented on Table 2. 
Tables 
Table 1

DuPont Marshall Laboratory

Summary of PFOA Soil Analytical Results

Total (T)/ Sample ID BS-8 (0-2') BS-8 (4-6') BS-9 (0-2') BS-10 (0-2') BS-10 (4-6') BS-10 (6-8') BS-11 (0-2') B

Analyte Units Diss. (D) Date 1/9/08 1/9/08 1/9/08 1/9/08 1/9/08 1/9/08 1/9/08 PFOA UG/KG T ND (0.79) NQ (0.68) NQ (0.60) NQ (0.63) ND (0.64) 5.1 ND (0.63) N

ND = Non detect at stated reporting limitNQ = Compound detected at a level between the limit of detection (LOD) and reporting limit (LOQ); result is not quantifiable.
Table 2

DuPont Marshall Laboratory

Summary of PFOA Groundwater Analytical Results 

Total (T)/ Sample ID A8 B4 BS-1 C13 C8 E4 G

Analyte Units Diss. (D) Date 1/9/08 12/20/07 1/24/08 1/18/08 1/10/08 12/18/07 1/15PFOA UG/L T 0.31 0.042 0.28 0.37 0.28 0.012 NQ (0.0

ND = Non detect at stated reporting limitNQ = Compound detected at a level between the limit of detection (LOD) and reporting limit (LOQ); result is not quantifiable.
Figure