DENR Rulemaking
#1692
Groundwater Standards for 18 substances
in 15A NCAC 2L .0202
October 16, 2000
e-mailed 10/16/00 to David.Hance@ncmail.net
David Hance
DENR-DWQ Groundwater Section
1636 Mail Service Center
Raleigh, NC 27699-1636
Re: DENR Rulemaking #1692
Groundwater Standards for 18
substances in 15A NCAC 2L .0202
Dear Mr. Hance:
On behalf of the Blue Ridge Environmental
Defense League, I write to comment on the
groundwater standards now under
review. First, the proposed
reductions of the 2L concentrations for
Atrazine and Simazine appear to be
prudent steps for the protection of
public health. I hope the EMC will
approve these lower concentrations.
Second, some of the compounds under
consideration should be approved at
levels lower than DEM's interim maximum
allowable concentrations.
CARBON
DISULFIDE
Systemic toxicity of oral carbon
disulfide ingestion is manifested
primarily in the liver. Moreover,
although the document for DENR Rulemaking
#1692 states that there is no evidence of
human or animal carcinogenicity in
available toxicological literature, it
does refer to evidence of teratogenicity
and fetal toxicity in rabbits.
The ATSDR Toxicological Profile for
Carbon Disulfide July 1994 (page 71)
includes an oral acute duration Minimal
Risk Level of 0.01 mg/kg/day based on
inhibition of hepatic enzyme
activity. Using ATSDR's MRL as the
reference value under 15A NCAC 2L
.0202(d)(1), the groundwater standard
should be 0.07 mg/L, a full order of
magnitude below DEM's interim maximum
allowable concentration. This would
be the concentration EMC should adopt
except for the water odor threshold value
(below).
The limit of 0.00039 mg/L, water odor
threshold value, should be adopted as the
standard. Title 15A NCAC 2L
.0202(d) states that "Groundwater
quality standards for substances in Class
GA and Class GSA groundwaters are
established as the lesser of: (4) Odor
threshold limit value;" among
others.
CHLOROETHANE
The limit of 0.019 mg/L, water odor
threshold value, should be adopted as the
standard. Title 15A NCAC 2L
.0202(d) states that "Groundwater
quality standards for substances in Class
GA and Class GSA groundwaters are
established as the lesser of: (4) Odor
threshold limit value;" among
others.
CHRYSENE
The limit of 0.0002 mg/L should be
adopted as the standard. Data which
is more specific to the compound under
consideration should outweigh generalized
data based on other compounds in the same
chemical class, i.e. PAH. The
document for DENR Rulemaking #1692 states
correctly that the rules require the
groundwater quality standard to be
established as the lesser of the values
and calculations in 15A NCAC 2L
.0202(d)(1-6). The 1990 USEPA MCL
of 0.0002, although developed before
guidance document EPA/600/R-93/089, is
the lesser of the values. Data does
not have an expiration date. It can
be disproved or superseded by better
data, but it cannot go
"out-of-date."
I plan to submit further comments before
the November 6 comment deadline.
Respectfully,
Louis Zeller
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