DEQ-CFW_00026627

Hazardous Waste Section
File Room Document Transmittal Sheet
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Y our Name:
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Larry Stanley
N C D 0 4 7 3 6 8 6 4 2
DuPont -Fayetteville
Corrective Action (CA)
Environmental Indicators (EI)
Comments on CA 725 & CA 750 El evaluations
8/3/2012
HWS
File Room Use Only NCD047368642
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DEQ-CFW-00026627

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Stanley, La
Subject: DuPont Fayetteville: Comments on El Evaluations
Date: 8/3/2012
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Below are the comments for the DuPont -Fayetteville El's that we discussed on the telephone (a couple have been
added). From this end, they seem pretty straight -forward. Please address them and send revised pages, and I will insert
the new pages into the El reports.
1)QuestknL2 (Page x and in Section 5.2.3) —EPA's VISL Work Sheet was used to calculate an indoor air screening value
fortetrach/oroethene. The HWS recommends that DuPont include a copy of the completed VISL Work Sheet as an
appendix tothe [A72Sevaluation.
2) Question 3 (Page xii and in Section 6.2) - Question 3 does not address the potential for a completed exposure
pathway between contaminated media and trespassers. This exposure pathway is included in EPA's CA-725
Questionnaire, and the potential risks to trespassers posed by contaminated media should be discussed in DuPont's
evaluation. (Note that trespassers are mentioned in Section 6.2-Exposure Pathways.)
3) Tables: CA 725 Evaluation — Some tables in DuPont's CA 725 evaluation are color coded. A legend that explains the
meaning of each color should be added at the front of the tables. (A similar legend is present at the front of Table 1-
Groundwater Analytical Results in the CA 750 report.)
4) Question 2 (Page viii) — The answer to Question 2 indicates that the analytical results for four samples collected as
^ grab samples" are part ofthe groundwater data set. The sources ofthese samples (i.e,collected from private wells,
excavations, etc.) should be stated in the text, and the sample identifier used in Table 1-Groundwater Analytical Results
should bementioned.
5) Question 3 and Section 7.0 (Paragraph 2) —The text of Section 7 explains that the clay lens extends farther north than
the perched groundwater. The phrase "no perched water flow component toward Willis Creek" implies that perched
water is present but does not flow to the north and, therefore, cannot discharge into Willis Creek. Please clarify this
part of Paragraph 2.
6) Question 4 and Section 7.0 (Paragraph 3)— DuPont should mention the stream classification for Willis Creek in
Paragraph 3ufSection 7.U. Like the Cape Fear River, Willis Creek is probably a Class WS-IV surface water body. DuPont
s,hould verify the classification of Willis Creek and appropriately revise the text in this paragraph.
the text of the CA 750 report?
Regards,
Larry3tanley
NC Hazardous Waste Section
NCDivision ofWaste Management