DEQ-CFW_00000223

IN
MEMORANDUM
January 30, 2017
To: Linda Culpepper, Deputy Director
Division of Water Resources
From: David Lilley, ]Environmental Toxicologist
Division of Waste Management
Through: Michael Scott, Director
Division of Waste Management
ROY COOPER
ivlltaHAEL S. REGAN
P IS HAEL SCOT`r
k)r
RE: DWM Review of Proposed Groundwater Standards for Methyl methacrylate; 2-
Methylphenol; Perchlorates; Perfluorooctane sulfonic acid; Perfluorooctanoic acid;
Picramic acid; 2,4,5-Trichlorophenol; and 2,4,6-Tiichlorophenol
1. Perfluorooctane sulfonic acid: The CAS number at the top of the first page should be
changed to 1763-23-1.
2. 2,4,6-"Trichi orophenol, first page: The footnotes are incorrect, both the taste and odor
thresholds were obtained in Young, 1996. In addition, the values for taste and odor
appear to be reversed, the odor threshold should be 380 µg/1 and the taste threshold
should be 12 µg/l. The same information should be changed on page 2.
3. 2,4,5-Trichlorophenol, first page: The provided slope factor of 0.026 (mg/kg/day)-'
should be deleted.
4. 2,4,5-Trichlorophenol, first page: It is unclear why footnotes 6 and 7 cite the same
source. When this comment was made on the dalapon write-up, the Division of Water
Resources (DWR) response in the "response to comments" memo (]November 21, 2016)
and follow-up phone call was unclear. It is understood that one convention of numbering
footnotes requires they be listed numerically and consecutively, with subsequent
references to the, same work shortened to include only the author's last narne and page
number, However, since that convention was not followed for footnotes 2 and 4 in all the
previously submitted packages, it remains unclear as to why the taste and odor footnotes
are handled differently.
DEQ-CFW 00000223

Linda Culpepper
January 30, 2017
Page 2 of 2
5. 2,4,5-Trichlorophenol, second page, Recommended Groundwater Standard section, last
sentence: According to the first page, the recommended groundwater standard is based
on the odor threshold, not the calculated noncancer systemic threshold.
Perfluorooctanoic acid and perfluorooctane sulfonic acid: According to 15A
NCACO2L.0202(d), the groundwater standard is the least of the six listed criteria
(systemic threshold, carcinogenic threshold, taste limit, odor limit, maximum
contaminant levels, secondary maximum contaminant level). The following paragraph,
15A NCACO2L.0202(e)(2), allows the use of health advisories (among other resources)
when "used in establishing concentration of substances which correspond to levels
described in Paragraph (d) of this rule". I believe this means that the resources in
paragraph e can be used to establish the values in paragraph d. Does the DWR have the
authority under 2L to directly adopt a calculated health advisory, which uses different
assumptions than those outlined in 15A NCACO2L.0202(d)(1), as the groundwater
standard? If so, why have health advisories not been adopted as -groundwater standards
for other chemicals?
7. Perfluorooctanoic acid: Is reference 5 the same as reference 1?
8. Picramic acid; second page. fourth paragraph: Delete the second word or the third line,
"of' so the sentence reads "A human exposure concentration associated with an...".
Sim,, of Nrsrth CEorolino i Lnvironrnental duality I Watsre Maliayen7em
117 West Jont-b Stwel i 160 Mail SCI Vi L CCntvr I Raleigh, Norlh Carolinas 27699.1646
9ty 707 8200
DEQ-CFW 00000224