NC0003425_Comments on Draft Permit_20170221

DUKE
ENERGY.
Teresa Rodriquez, P.E.
NC Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617
Richard E. BakerJr., P.E. P.M.P
Director of Environmental Programs
Coal Combustion Products
526 S. Church Street
Mail Code:EC13K
Charlotte, NC 28202
(704)-382-7959
February 21, 2017 RECEIVED/NCDEQIDWR
FE8 21 2017
Perming Section
Subject: Comments on the DRAFT NPDES Permit for Roxboro Steam Electric Plant
Permit No.: NC0003425
Person County
Dear Ms. Rodriquez:
Duke Energy Progress, LLC submits the following comments on the draft National Pollutant Discharge
Elimination System Permit for Roxboro Steam Electric Plant, issued for public comment by the North
Carolina Department of Environmental Quality ("NCDEQ") on January 22, 2016. Duke Energy
appreciates NCDEQ's efforts to develop the Draft Permit, which addresses novel issues associated with
surface impoundment decommissioning and modifications required to facilitate those changes.
Finalizing this wastewater permit is a critical step to advance that process by authorizing decanting and
dewatering. In addition to these general comments, Duke Energy again offers the following comments
and requests for modification and/or clarification on specific provisions of the Draft Permit:
I. On page 2 of 29, Duke Energy requests the following calrifications and modificaitons:
a. Add "extracted groundwater" as a potential contributing flow to outfall 003 and outfall
001.
b. List the retention basin (internal outfall 012) as a potential flow path for internal outfall
005 (Cooling Tower Blowdown) in addition to the ash basin and the discharge canal.
c. List the retention basin (internal outfall 012) as a potential flow path for internal outfall
008 (Domestic wastewater treatment system) in addition to the ash basin. Upon
cessation of flows to the ash basin, flows from the domestic wastewater plant will be
directed to the retention basin (internal outfall 012).
d. List the retention basin (internal outfall 012) as a potential flow path for landfill leachate
as discussed in our August 2016 NPDES application update submittal (item #7).

e
12
2. On page 4 of 29, Duke Energy requests the sampling frequency for Acute Toxicity be designated
as "Quarterly" to align with the required frequency in condition A.(14) of the permit.
3. On page 5 of 29, Duke Energy requests revision of the footnote related to fly ash discharges to
indicate that no discharges of fly ash shall occur after November 1, 2018 as requested in Duke's
submittal from August, 2016. Also, please clarify in the footnote that this prohibition is related
to fly ash sluice water generated after November 1, 2018 only.
4. On page 5 of 29, Duke Energy requests the removal of the pH limitation from internal outfall 002
in accordance with request and documentation submitted dated October 31, 2016.
S. On page 7 of 29, Duke Energy requests the revision of the footnote related to fly ash discharges
to indicate that no discharges of fly ash shall occur after November 1, 2018 as requested in
Duke's submittal from August, 2016. Also, please clarify in the footnote that this prohibition is
related to fly ash sluice water generated after November 1, 2018 only.
6. On page 7 of 29 (Outfall 002 — dewatering), Duke Energy requests that the flow limit of 2.0 MGD
be clarified to only apply to interstitial water treated through additional physical/chemical
treatment system. Current flows from the ash basin are — 12-15 million gallons and can vary
significantly based on precipitation and stormwater flows into the basin as measured at outfall
002.
7. On page 7 of 29, Duke Energy requests that pH on the internal wastestreams be removed. EPA
has previously allowed commingling as a treatment for internal flows. Please see reference
documents previously submitted on other Duke Energy permits with this request (Attachment
1).
8. On page 8 of 29, Duke Energy requests the limits for Thallium be removed from the permit as
there is no numeric water quality criterion for Thallium in North Carolina. Please reference the
detailed request submitted by Duke Energy dated October 31, 2016 and attached to this
submittal for detail.
9. On page 10 of 29, Section A.(5), Duke Energy requests that language be added to the description
of the Cooling Tower Blowdown flow path to include the retention basin (internal outfall 012) or
the Heated Water mixing Zone.
10. On pag 11 of 29, Duke Energy notes a new limit for selenium from outfall 006. The fact sheet
indicates that this limit was inserted as the result of a single reported sample point during the
last 10 years. Duke requests that the montly average be removed. NPDES outfall 006 is
essentially a stormwater outfall with flows being generated from runoff from the coal pile and
limestone pile areas. As such, Duke requestes that the limits for selenium be modified to be

Page 13
consistent with only the "benchmark" value of 56 ug/1 in stormwater permits issued to Duke by
the Department of Environmental Quality for this and other facility's. A review of the DMR data
for outfall 006 submitted by the facility confirms that discharges from this outfall are not
continuous and are primarily associated with precipitation events leading to volumes of runoff
from the coal pile. In the absence of removing the monthly average limit, Duke requests that a
compliance schedule be included in the permit to study selenium levels at outfall 006 and plan,
engineer and implement modifictions to assure compliance with the monthly average limit.
11. Duke Energy requests that pH limits for internal outfalls 008, 009, 010, 011, 012A and 012B be
removed. Please reference the detailed attached submittal dated October 31, 2016 with regard
to comments on the inclusion of pH limits on internal outfalls.
12. On page 20 of 29, Duke Energy requests the addition of the following language at the beginning
of Section A. (15) Seeps: "All previously identified seeps from this facility are contributing flows
to permitted outfalls 001 or 003. There are no seeps that discharge directly to jurisdictional
waters." Duke further requests that a list of the previously identified "seep" flows that are
tributary to outfall 003 be included in the permit as has been done for flows tributary to outfall
001. Seep flows that are tributary to outfall 003 are enumerated in paragraph 15 of the NPDES
permit application update submitted to the DEQ dated August 15, 2016.
13. On page 23 of 29, Duke requests clarifying language in condition A.(19)(b.) that temperature
readings from the afterbay release to Hyco River will be obtained from the exisiting USGS
gauging station at this location (02077303) and that malfunction of the USGS gauging station
which results in data not being recorded will not be considered a violation of the permit
requirements.
14. Duke Energy requests removal of the monthly average limit of selenium for outfall 001. Flows
from outfall 001 are similar to those from outfall 006 in that they are largely driven by
precipitation and stormwater flow through the remnant section of the East Ash Basin. There
has been no noted seepage from S10, S11 or 512 in the last two years. With that being the
operational scenario, a daily maxium value for selenium is appropriate at this location as
discussed in #10 above.
Duke Energy welcomes any further discussion on our comments or the Draft Permit. If you have any
questions, please contact Shannon Langley at 919.546.2439 or at [e-mail].
Sincerely,
10 ,
Richard E. BakerJr., P.E., P.M.P
Director of Environmental Programs - CCP
Duke Energy

Page 14
Attachments
Cc: Mr. Jon Hennessey—Roxboro Public Hearing officer
1617 Mail Service Center
Raleigh, NC 27699-1617
Bc: Jason Haynes- Roxboro Station Manager
Jim Wells, VP — Duke EHS CCP
Robert Howard —Sr. Environmental Specialist, Roxboro Station
Shannon Langley - NCRH 15
Lori Tollie — EHS CCP

Attachment 1
RECEIVEDINCDEODWR
FEB 21 2017
Water Quality
Permitting Section
Evaluation of Toxicological Information of
Thallium prepared by Haley and Aldrich for
I

Thallium Toxicity Value Review
EVALUATION OF THE TOXICITY VALUE FOR THALLIUM
1. Current Screening Provisional Toxicity Value
There is not currently an oral chronic reference dose (RfD) toxicity value for thallium established by the
United States Environmental Protection Agency (USEPA) Integrated Risk Information System (IRIS) or
from an USEPA Provisional Peer -Reviewed Toxicity Value (PPRTV) assessment. The USEPA PPRTV
document for thallium (TI) concluded that it is inappropriate to derive a provisional subchronic or
chronic provisional RfD (p-RfD) for thallium; however, USEPA states that information is available which,
although insufficient to support derivation of a provisional toxicity value under current guidelines, may
be of limited use to risk assessors (USEPA, 2012). The PPRTV document contains a separate Appendix A
that provides rationale for the derivation of a subchronic and chronic "screening provisional oral
reference dose" forthalliurn compounds of 0.00004 mg TI/kg-day and 0.00001 mg TI/kg-day,
respectively. Appendix A of the PPRTV document also notes that, "Users of screening toxicity values in
an appendix to a PPRTV assessment should understand that there is considerably more uncertainty
associated with the derivation of a supplemental screening toxicity value than for a value presented in
the body of the assessment (USEPA, 2012a)." The screening p-RfD is expressed in units of milligrams of
thallium per kilogram of body weight per day (mg TI/kg-day).
Due to limitations in the toxicology database and general poor quality of available studies, the USEPA
IRIS Toxicological Review of Thallium and Compounds (USEPA, 2009) also concluded that reference
doses or reference concentrations could not be derived for human health following thallium exposures.
2. Information on Human Exposure to Thallium
The conservative nature of the p-RfD can be illustrated by considering the amount of thallium ingested
daily by Americans in their diet. It is estimated by the World Health Organization (WHO) and the U.S.
Agency for Toxic Substances for and Disease Registry (ATSDR) that a 70 kilogram adult ingests
approximately 0.005 mg thallium per day in the diet, especially from consumption of home-grown fruits
and green vegetables (WHO, 1996; ATSDR, 1992). This is equivalent to a daily dose of 0.00007 mg Tl/kg-
day. The USEPA supplemental p-RfD for thallium is 1E-05 mg/kg -day (0.00001 mg/kg -day). This is seven
times lower than the estimated dietary intake. In other words, use of this dose -response value to
evaluate natural dietary exposure to thallium would indicate a hazard that is unlikely to exist.
Stated another way, assuming that an average adult weighs 70 kg, and using the screening level p-RfD of
0.00001 mg/kg bw-day, it could be concluded that an adult should not consume more than 0.0007 mg
TI/day, which is well below the estimated dietary intake of 0.005 mg thallium per day in the diet.
Currently, there have not been substantial reports of toxicological effects associated with typical dietary
ingestion of TI in the general population, suggesting that the use of the "screening provisional oral
reference dose" greatly overestimates the potential risks associated with oral exposure to TI
compounds.
The 90th percentile adult urinary thallium elimination from the National Health and Nutrition
Examination Survey (NHANES) (CDC, 2016) is 0.380-0.390 micrograms per liter (ug/L) which is about
0.760-0.780 ug/day in the urine alone. This suggests that greater than 10% of Americans, and probably
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Thallium Toxicity Value Review
closer to 50% of Americans, ingest more than the screening level p-RfD. From the IRIS assessment
conducted in 2009, a reviewer stated that there is no evidence that thallium in the current U.S. diet
poses any threat, and the adoption of this screening level p-RfD would produce unnecessary concern if
the above calculation is correct. This indicates the poor quality of the existing data, and brings into
question the validity of the analysis using the available data on thallium used by USEPA (USEPA, 2009).
3. Derivation of the Current Screening Provisional Toxicity Value
Below is a summary of the data and assessment that was used by USEPA in the derivation of the oral
chronic screening level p-RfD for thallium.
3.1 HAZARD EVALUATION/STUDY SELECTION
Note: Human or animal studies examining the carcinogenicity of thallium following oral exposure are
not available. The cancer weight -of -evidence (WOE) provided in the IRIS review (USEPA, 2009) is listed
as "Inadequate Information to Assess Carcinogenic Potential (both oral and inhalation)."
3.1.1 I-iurnan
Most information on thallium toxicity in humans comes from poisonings, suicide attempts, or accidental
exposures. Symptoms observed after acute exposures to high doses of thallium in humans include
alopecia (hair loss), gastrointestinal disturbances, and neurological symptoms such as paresthesia and
neuropathy. Epidemiologic studies of either the general population or occupationally exposed groups
are limited by inadequate study design, undefined exposure parameters, and inconclusive associations
between thallium exposure and specific health effects. Therefore, USEPA (2012a) concluded in the
PPRTV document that "available human studies do not support oral RfD derivation."
3.1.2 Animal studies
Studies in animals show that oral exposure to thallium produces effects similar to those observed in
humans, most notably, alopecia. Other findings observed in animal studies include biochemical
changes, lipid peroxidation, liver and kidney damage, and histopathologic changes in the brain and
nerves. The doses at which these systemic effects were observed range from 0.2 —1.8 mg TI/kg-day
(ATSDR, 1992). Reproductive and developmental studies in animals show some evidence of adverse
effects upon oral exposure to thallium at doses of 0.08 mg TI/kg-day —1.6 mg TI/kg-day; however,
available studies have significant limitations and the same effects have not been observed in humans
(ATSDR, 1992).
Only four repeat -dose oral toxicity studies with more than one dose level are available in animals. Of
these four studies, three were not considered adequate for RfD derivation (USEPA, 2009).
3.1.3 Conclusion
The conclusion reached in the IRIS Toxicological Review (USEPA, 2009) was that the available toxicity
database for thallium contains studies that are generally of poor quality. One animal subchronic study
conducted by the Midwest Research Institute (MRI, 1988) was selected as a candidate principal study for
November 2016 24 v L
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Thallium Toxicity Value Review
RfD derivation but was found to include critical limitations such as high background incidence of
alopecia, lack of histopathological examination of skin tissue in low -and mid -dose groups, and
inadequate examination of objective measures of neurotoxicity, thus making it difficult to select
appropriate endpoints. On this basis, a RfD for thallium salts was not derived by IRIS (USEPA, 2012a).
3.2 BASIS FOR PROVISIONAL SCREENING ORAL CHRONIC P -RFD
As indicated above, the PPRTV assessment (USEPA, 2012a) does not derive a typical provisional toxicity
value for thallium but rather uses the limited toxicological information to develop a screening level
value.
3,2..1 .Study Selection
A 90 -day Good Laboratory Practice (GLP) oral gavage study in male and female rats conducted with
thallium sulfate by MRI (1988) was selected as the principal study for the screening level p-RfD. Doses
were approximately 0, 0.008, 0.04, and 0.2 mg TI/kg-day.
3.2.2 Selection of
Several critical endpoints were considered, but ultimately USEPA (2009) considered only two endpoints
to be appropriate for a screening level p-RfD development:
Hair follicle atrophy in female rats that also had alopecia; and
r Clinical observations related to animal coat, eyes, and behavior.
The clinical observation endpoint was discounted because the underlying basis for the observations is
unknown. Hair follicle atrophy was determined to be most consistent with the atrophic changes
observed in cases of human thallium poisoning and may be best indication for human response to
thallium exposure.
MRI (1998) concluded that the minor dose-related changes in the study did not affect the health status
of the treated animals and were not toxicologically significant. MRI considered the highest dose (0.2 mg
TI/kg-day) as the no -observed -effect level (NOEL). However, USEPA conducted its own analyses of the
raw data from the study to come up with different conclusions. Of the 12 high -dose females with
alopecia, 5 instances were not totally attributed to barbering behavior. Histopathologic examinations
revealed atrophy of the hair follicles in two high -dose female rats that also had alopecia. It was noted
that there were no discernable differences in either the severity or distribution pattern of alopecia
across control and treated groups (USEPA, 2009).
The high dose (0.2 mg TI/kg-day) was identified by USEPA as the LOAEL. Because histopathology of skin
tissue from the low -and mid -dose groups was not conducted, the NOAEL for this endpoint cannot be
determined with certainty. Given the low incidence of hair follicle atrophy in females in the high dose
group and absence of cases of hair follicle atrophy in male rats, USEPA (2012a) assumed that the mid -
dose could be used to approximate a NOAEL for skin histopathology.
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Thallium Toxicity Value Review
Therefore, the estimated NOAEL of 0.04 mg TI/kg-day was used as the point of departure (POD) for hair
follicle atrophy (USEPA, 2012a).
3.2.3 Uncertainty Fa(torr,
Using the NOAEL of 0.04 mg TI/kg-day for hair follicle atrophy and using an uncertainty factor (UF) of
3000, the screening level p-RfD was calculated to be 0.00001 mg TI/kg-day. Justification for the applied
OF is summarized in table below.
Table 1: Uncertainty Factors Applied by USEPA in Screening Level p-RfD Derivation
Uncertainty Factor Justification
10 Extrapolation from laboratory animals to humans since no information is
available to characterize the toxicokinetic differences between experimental
animals and humans.
10 Variation in human susceptibility in the absence of information on the
variability of response to thallium in the human_ population. _
10 Lack of adequate developmental toxicity studies and a two -generation
reproductive study, and additional uncertainty associated with the limited
data available on neurotoxicity.
3 Extrapolation from subchronic to chronic exposure duration. Effects on the
coat/skin as well as other clinical observations occur within weeks of exposure
to thallium (does not required chronic exposure in order to manifest).
Composite OF = 3000 -- -- —
Note that there are considerable and critical limitations with the principal study selected by USEPA
(2009) including:
High background of incidence of alopecia (POD selected)
• Lack of histopathological examination of skin tissue in low -and mid -dose groups
Inadequate examination of objective measures of neurotoxicity
4. Other Available Sources for Derivation of Toxicity Values for Thallium
The following sections describe sources consulted for information on the toxicology of thallium.
The World Health Organization (WHO) (1996) concluded that in the general population, environmental
exposure to thallium does not pose a health threat. The total intake has been estimated to be less than
5 ug/day with the vast majority coming from foodstuffs; drinking -water and air generally contribute very
small amounts of thallium. Concentrations of thallium in urine may be considered a relatively reliable
indicator of exposure. Exposure to thallium resulting in urine concentrations below 5 ug/liter is unlikely
to cause adverse human health effects. The estimated daily oral intake corresponding to a urinary
thallium concentration of 5 ug/liter in urine is approximately 10 ug thallium in the form of a soluble
compound. Assuming an average adult body weight of 80 kg (USEPA, 2014), this would be equivalent
to 0.000125 mg/kg -day which is a 10 -fold factor above the USEPA screening level p-RfD. The WHO
November 2016 4

Thallium Toxicity Value Review
Task Group thus concluded that "in view of the considerable uncertainties in the evaluation, it was not
possible to recommend a health -based exposure limit. Until better information on the dose -response
relationship becomes available, it seems prudent to keep human exposures at levels that lead to urinary
concentrations of less than 5 ug/liter." In reviewing the animal studies, the WHO Task Group also noted
that, "it appears that an intake of 0.01 mg/kg -day may be associated with adverse effects. No doses
lower than this have been tested."
4.2 ATSDR
ATSDR (1992) notes, "Data on effects of intermediate duration oral exposure in animals do not reliably
identify the most sensitive target organ or the threshold for adverse effects. No data on effects of
chronic -duration oral exposure to thallium were located. Therefore, intermediate -duration and chronic -
duration oral minimum risk levels (MRLs) were not derived for thallium." !Vote that review of the MRl
1988 study (originally Stoltz 1986) was conducted by ASTDR but not usedin the derivation of the MRL.
.,3
USEPA's Maximum Contaminant Level (MCL) (USEPA, 2012b) for drinking water is 2.0 ug/L or 0.002
mg/L. The USEPA Human Health Water Quality Criteria (HHWQC) (USEPA, 2015) for thallium is 0.24 ug/L
or 0.00024 mg/L for the consumption of water and organisms from a surface water body, and is 0.47
ug/L or 0.00047 mg/L for the consumption of organisms only. These levels were derived based on the
90 -day subchronic study in rats (MRI, 1988).
4A CALIFORNIA EPA
In California, the MCL and Public Health Goal (PHG) for thallium in drinking water are currently set at 2.0
and 0.1 ug/L, respectively (CaIEPA, 1999, 2004). The Office of Environmental Health Hazard Assessment
(OEHHA) prepared the PHG for thallium in drinking water also using the MRI (1988) study in which
alopecia was observed in both male and female rats and consistent with other reports of toxicity of
thallium in both experimental animals and in humans. OEHHA determined that the incidence of
alopecia in female rats at the highest dose of 0.25 mg/kg -day represented a biologically significant
effect. Therefore, the no -observed -effect -level (NOEL) was identified to be the administered mid -dose
level of 0.04 mg TI/kg-day. For the calculation of the PHG, a cumulative uncertainty factor of 3,000 was
incorporated to account for the use of a subchronic study, uncertainty in inter -and intra -species
extrapolation and the steep dose -response curve. Based on these uncertainty factors, OEHHA derived a
PHG for thallium in drinking water of 0.0001 mg/L (0.1 ug/L). OEHHA notes that USEPA chose to
consider the dose that resulted in alopecia and increased serum enzymes indicated of liver damage as a
NOAEL, which is why the federal values are higher than those estimated by OEHHA.
4.5 CANADIAN COUNCIL OF MINISTERS OF THE ENVIRONMENT
The Canadian Council of Ministers of the Environment (1999) also adopted the USEPA screening level p-
RfD based on the MRI (1988) study as a provisional tolerable daily intake (TDI) for derivation of health -
based soil quality guidelines for thallium at contaminated sites in Canada.
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Thallium Toxicity Value Review
No data were available on thallium or thallium compounds on the European Chemical Agency (ECHA)
Portal where the Registration, Evaluation, Authorization and Restriction of Chemical Substances (REACH)
Registration Dossiers are posted (ECHA, 2016). Thus, no derived no effect level (DNEL) is available for
thallium from this source.
4.7 OTHER
No other relevant data were located with respect to thallium toxicity since the publication of the USEPA
PPRTV assessment that could better inform the dose -response assessment and toxicity value derivation
for thallium.
5. Critique of Toxicity Value for Thallium
The current screening level p-RfD currently being used by USEPA as a toxicity value is a highly
conservative and inappropriate value for use in evaluating human health risks from oral chronic
exposure to thallium on the basis of: 1) the lack of appropriate toxicological studies on subchronic and
chronic exposures to thallium that provide relevant data and endpoints to be used in a dose -response
assessments; 2) the fact that other regulatory authorities (ATSDR, WHO) have concluded that sufficient
data on thallium does not exist and have not generated toxicity values for thallium and have placed a
low priority on development of additional toxicology data for thallium; 3) the study and POD using
alopecia as the endpoint as selected for the derivation of the screening level p-RfD by USEPA (2012a)
results in significant uncertainty to the applicability of the effects to human exposure to thallium; and 4)
the screening level p-RfD greatly overestimates the risk associated with human exposures as compared
to the typical ingestion of thallium in foods.
5.1 TOXICOLOGY DATABASE ON THALLIUM
The toxicity database for thallium in consideration of a dose -response assessment and derivation of a
toxicity value is limited. Low confidence in the screening level p-RfD is attributed to the limited
database including the lack of studies addressing the known toxic effects of thallium including
neurotoxicity, developmental toxicity, and endocrine effects, and failure of the MRI (1988) study to
identify a NOAEL of all relevant endpoints are considered. It is questionable as to whether a screening
level p-RfD should have been derived and if such an analysis is even valid knowing the database
limitations resulting in the application of such high uncertainty factors, given USEPA's own discussion of
the limitations in the PPRTV document (USEPA, 2012a).
5.L OTHER REGULATORY SOURCES/VALUES
Most regulatory sources acknowledge the paucity of data for thallium and have not derived toxicity
values. USEPA IRS, WHO, and ATSDR have not generated oral chronic RfDs for thallium. For those that
have, the MRI (1988) study has been identified as the principal study despite the fact that it has not
been published in a peer-reviewed journal, did not provide statistical analyses, and the study did not
show a statistically significant dose -response effect for alopecia in male rats.
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Thallium Toxicity Value Review
On the Priority List of Hazardous Substances established by ATSDR last updated February 12, 2016,
thallium is listed as #275 out of 275 compounds indicating its low priority and concern for review
(k!tturLvv'. �tsdr.cdc.eovi�PL/). In addition, the National Toxicology Program (NTP) (2016a) has
reviewed petitions and proposals for conducting additional toxicology studies on thallium to decrease
the limitations and uncertainty with the current toxicology database but in a recent meeting on June 15,
2016, the.NTP scientific board placed low priority on moving forward with these efforts.
One could infer that the low priority established by regulatory authorities on continued development
and review of the toxicology data for thallium indicates a low concern of the potential for human health
risk effects of oral exposures to thallium as compared to other compounds.
STUDY SELECTION AND POE)
It has been questioned as to whether alopecia is considered an adverse event and should have been
used as the POD for the screening level p-RfD. USEPA has stated: "Whether alopecia is itself an adverse
effect merits consideration. In humans, alopecia is generally reversible upon cessation of thallium
exposure. Alopecia, however, appears to be a part of a continuum of dermal changes observed
following thallium exposure, as well as one of a spectrum of effects on target organs that include the
nervous and gastrointestinal systems. For these reasons, alopecia supported by two cases of hair follicle
atrophy is considered an adverse effect (USEPA, 2009)." USEPA (2009) acknowledged that other factors
such as caging and husbandry can cause alopecia in laboratory rodents; however, the incidence was
clearly elevated in both male and female rats over controls. Further, to the extent that alopecia was due
to barbering, research has shown that barbering in rodents can reflect a stress -evoked behavioral
response. For these reasons, some IRIS reviewers thought it was reasonable to use the alopecia as a
"biomarker" for adverse effects until additional studies are conducted to better identify adverse effects
of thallium exposures in animals and/or humans.
NTP (2016b) has also noted that the dose selection for the subchronic study was deemed inappropriate
for evaluation of alopecia since the 14 -day range -finding study performed prior to the 90 -day study
indicated hair follicle alterations together with decreases in body weight at a dose of 2.5 mg/kg -day of
thallium sulfate; however, a dose of ten times lower than that which effects were noted, 0.25 mg/kg -day
thallium sulfate was chosen as the high dose in the subchronic study. Further, review of the results also
show that there were challenges in distinguishing between normal hair cycling, self -barbering, and
incidences of true alopecia.
Since hair follicle histopathology and self -barbering is not a standard assessment in subchronic studies, it
is difficult to know whether what was observed in the MRI study (1988) is within the range of normal or
truly adverse. Therefore, the use of this endpoint as the POD brings considerable uncertainty to the
screening level p-RfD derived using these data.
No other studies have been identified by reviewers that could bring more certainty and validity to the
current screening level p-RfD proposed by USEPA (2012a).
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Thallium Toxicity Value Review
6. Final Assessment
Due to the significant uncertainty surrounding the study selection and uncertainty to the relevance of
adverse effects in the selected study and POD, the screening level p-RfD value as provided in Appendix A
of the USEPA PPRTV document for thallium (USEPA, 2012a) greatly overestimates potential risks
associated with exposure to TI. This is supported by other regulatory and authoritative agencies
concluding that the dataset is currently insufficient for derivation of a non -cancer value for TI. In
addition, current intakes of TI for a substantial part of the population exceed the provision screening
value with no reported adverse effects reported, which also suggests that the current value is unrealistic
for purposes of regulatory decision making.
Therefore, it seems most appropriate to establish a screening level based on the level of thallium in the
diet; clearly exposure to thallium at this level are without adverse effects. Using the information from
WHO (1996) that the estimated daily oral intake corresponding to a urinary thallium concentration of
5 ug/liter in urine is approximately 10 ug thallium in the form of a soluble compound, and assuming
an average adult body weight of 80 kg (USEPA, 2014), a RfD of 0.000125 mg/kg -day can be calculated,
which is a 10 -fold factor above the USEPA screening level p-RfD. This value is still a conservative
derivation, considering that it is well below the intake of 0.01 mg/kg -day that WHO indicated was the
lowest associated with adverse effects.
7. References
1. ATSDR. 2004. Toxicological Profile for Cobalt. U.S. Department of Health and Human Services,
Public Health Service, Agency for Toxic Substances and Disease Registry. Available at:
2. CDC. 2016. National Health and Nutrition Examination Survey. U.S. Center for Disease Control and
Prevention. Available at: htt�; j��rl;va.".ri1r_ ea vincl`.51r�i� ries
3. CaIEPA. 1999. Public Health Goal for ThaIlium in Drinking Water. Office of Environmental Health
Hazard Assessment (OEHHA). Available at:
4. CaIEPA. 2004. Update of Public Health Goal (PHG)-Thallium. Office of Environmental Health Hazard
Assessment (OEHHA). Available at:
litt lloe h '_4 ca L,^ t l,,
S. Canadian Council of Ministers of the Environment. 1999. Canadian soil quality guidelines for the
protection of environmental and human health: Thallium (1999). In: Canadian environmental quality
guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg. Available at:
6. ECHA. 2016. ECHA Portal for Registration, Evaluation and Authorisation of Chemicals (REACH)
Registered Substances. European Chemicals Agency (ECHA). Available from:
November 2016 8 "RSICH

Thallium Toxicity Value Review
7. OEHHA. 1999. Public Health Goal for thallium in drinking water. Office of Environmental Health
Hazard Assessment, Berkeley and Sacramento, CA. Accessible at
htt :www v.aehlna ca.ec; r'vgater t?c 3, _X-Pair?1
_P __ _._.
8. NTP. 2016a. NTP Board of Scientific Counselors Meeting. Webinar presentation. Thallium
Compounds. June 15. See: lyes; int .niehs-r?iii. ov akaeut. ori lyse:/n??ctin s' est int�ex.lttr ,:!
9. NTP. 2016b. Draft NTP Board of Scientific Counselors Meeting. NTP Research'Concept: Thallium
Compounds. June 15-16. Avallable at:
htt iii .nIilS.iii3PT•aOl�f;P�c�7GUt rittj'l2SC/Z(7i E 36?t" rfflt?ctiln ?%er�ITldit'riaiSf't Estliill ?i-
�.1
10. USEPA. 2009. Toxicological Review of Thallium and Compounds -In Support of Summary
Information on the Integrated Risk Information System (IRIS). September. Available at:
11. USEPA. 2012a. Final Provisional Peer Reviewed Toxicity Values for Thallium and Compounds.
Superfund Health Risk Technical Support Center, National Center for Environmental Assessment,
Office of Research and Development, US Environmental Protection Agency, Cincinnati, OH.
Available at:hjtj; i, ?,;,:�
ni i a. t. 0
12. USEPA. 2012b. USEPA 2012 Edition of the Drinking Water Standards and Health Advisories, Spring
2012. U.S. Environmental Protection Agency. Available at:
liter: 'rnis.orn�vLtir�cumen?ts 2]12 drinci�=g ��dc1"er.p/�if
13. USEPA. 2014. Human Health Evaluation Manual, Supplemental Guidance: Update of Standard
Default Exposure Factors. OSWER 9200.1-120. February6, 2011. U.S. Environmental Protection
Agency. Available at: inT: ire• is��;on/FxefZvPf�F.chiiP1��3f=SQN�.PUF?uocke;r_-1?]_t?�i,tV P�c,.pt�F
14. USEPA. 2015. Human Health Ambient Water Quality Criteria. U.S. Environmental Protection
Agency. Available at: r—t--....
—fir°L'ev,v.�:�,a
15. WHO. 1996, Thallium. Environmental Health Criteria 182. World Health Organization. Available
at: Iltf�7: �flJ4'W,itif.!?eilt.C.inlCi:?fi;ii r a.
November 2016 9

Attachment 2
Reference document on internal pH limits
related to ELG's

ti
UNITED STATES ENVIRONMENTAL. PROTECTION AGENCY
WASHINGTON, D.C. 10440
Mr. Louis CanZiani
New York State
Department of Environmental
Conservation
Room 6126
Two world Trade Center
New York, NY 10047
Deer Mr. canziani:
This is to confirm our recent conversation regarding
effluent limitations guidelines for the steam electric power
industry (40 CFR Part 423).
In my letter of June 22, 1984 to Ms. Ursula Basch of
your office, I summarized the applicability of the steam
electric regulation pH limitat-ion as applicable to low volume
waste streams when such wastewaters are commingled with
(once through) cooling waters. The interpretation that I
provided was not in accord with prior information and instruc-
tions provided to EPA and State permitting authorities on
this subject.
The pH limitation per Part 423 applies at the "end -of -
pipe" discharge to surface waters when the wastewater discharge
contains tow volume wastewater thst is commingled'with once -
through cooling water. However, the intent of Part 423 is
also that the total suspended solids and oil and grease
limitations epplicable..t.o low volume waste streams be applied
to the low-volume waste component of such a combined discharge
prior to cOmmingling of the individual waste streams.
1 apologize for any Confusion in permit development or
delays in permit issuance that mey have occurred in this
matter. If you hive any further questions, please contact me
at [phone].
Sincerely,
Dennis Ruddy'
Project Officer
Industrial Technology Division

•' ' �'•' '"^' •^`r �r�•rr\Vr+MLr�II\` r rtVICIIIVrl AVLryII {y
r 4 7• -
JUN 2 2 199-4
Ms. Ursula Nasnh
New York State
Department of Environmental
Conservation
Room K126
2 World Trade% Centpr
New York, New York 13047
Dear Ms. Basch:
This is in res3)onse to' your questions during our
discussion on June 21 regarding the effluent limitations
guidelines for the steam electric industry (40 CFR Part 423).
T e pH limitatio pplirabtF to low volume waste streams
is int ded to require that low volume waste streams he
treated, as necessary, to comply with the PH limitation prior
to discharge. Furthermore, the basis for compliance with the
PH limitation is not buffering or dilution provided by cooling
waters or other waste streams which are commingled with low
volume wastes.
I trust that this information is responsive to your
questions. Please call me if you have any further questions.
(202-332-7165)
Sincerely,
Dennis Ruddy
Project Officer
Effluent Guidelines Divis4cn
4

I
ca
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION III
���aaa00� 6TH AND WALNUT STREETS
PHiLADELPHIA. PENNSYLVANIA 19106
In reply refer to -�
3EN21
March lo, 1976 i ..J. H. LONG
Mr. .Tames Long -.'1-
7— t �
i
Power Plant Services Section -------
Philadelphia
---Philadelphia Electric Company �
2301 Market Street
Philadelphia, Pennsylvania L9101
Dear Mr. Long:
This is in response to your accond progress report subaitt d February 10,
1976 for thLa Cha tdr Generating Station (PA 0011614), in which you propose to d:
charge boiler blowdvwn, zeolitc softener regeaerateB, and cvaporator blowdonn u
the receiving stream without pH neutralization. Plersra be advised that
40077R Part 423.32(b) (1) requires the pH of all discharges from paver plants
(except once -through cooling water) to be in. the range of 6 - 9. Econa:mict
were considered prior to the development of the final guideline limitations,
therefore the expense you hava cited as being associated with neutralizing these
effluent stresms is not a valid argument against trey went.
`pr
..
A policy decision waa made during the -EPA-PEA meeting in Washington, D.C.
that may influence your situation with respect cp neutralizing these effluent
streams. It was decided that waste streams could be combined with cooling water
for the so a on as as
s
th_.e pH range of 6 - 9. Thia_c not inconsi with uideliaa re re-
menta. It�sf�w73�s noted however, that pollutant parameters other than pH wil:
F•e limited anti >moa3toz r or —to com�b�aat�3.on-o`a part cu a.r waste source
cat,C with coo33n9 vator.
=
I trust thio will enable you to complete your treatment plans. If there
7.
are any questionz, please don't hesitates to contact me at 215 597-3689.
r,
Sincerely yours r
Bruce P .Snaith
Delmarva -D.C. Section
.,c

Consolidated Edison Company of New York, Inc.
4 trvin_9 Place, New York, N.Y. 10003
September 21, 1984
Mr. Dennis Ruddy (WH -552)
Project Offices
Effluent Guidelines Division
U.S. Environmental Protection Agency
401 M Street-S.W.
Washington D.C. 20460
Re: pH Limits on Power Plant
Internal Waste Streams
Dear Mr. Ruddy:
Enclosed". for' y.ouf :information".. is a':copy'• of. Con Edison '.s
comments to- NYSDEC concerning proposed pH -limits and monitoring
requirements specified in the draft renewal permit for Con
Edison's Waterside Station. These comments expand upon Con
Edison's position concerning pH limits on internal waste streams,
as expressed during our August 10 meeting and detailed in previ-
ous correspondence, (In particular, see p.5, paragraph 2,
section 3(a)(5), section 3(b) and section 3(c) for new/expanded
arguments).
If you have any questions, please contact me at (212)
460-2522, We look forward to further discussions with you
concerning this issue.
Very truly yours,
oma•' .
Barry H. Cohan
Senior Environmental Engineer
Water & Waste Management
/gP
Attachment
cc: Mr. J. William Jordan (EAI -336)
Chief
NPDES Technical Support Branch
U.S. Environmental Protection Agency
401 M Street S.W.
Washington D.C. 20460
N

f
�. DF F.equiremer.ts (See Ef.`.+_uert L.imitatior.s .rd ?scritcring
ReauirPmerts, p.2):
DEC proposes t_r.. ma.irtair the current pp 14_74-tetixn (range of
K0-9.07 for ^ischarge 002 and delete the currer.t 6.0-9.-0 VF
limitation fl r Discharge 001. DF.0 al—co nropcses tc add n.?
limitations (6.0-9.0) `cr iinten al w-,stP Streams 001a
(boiler blowdovn) , 001b (1-7aterside 'No. 1 demineralizer
reaereratior_ wastes) , 001c (floor and equipment drainage)
and 0022 (icaterside FQ.2 demireralizer reger.evatior. wastes) .
it addition, DEC has prcposed to delete p1' moniterinE
requirements at Disch2r?e 001, revise the pu mcnitor-r.€
frnouencv io. Discharge 002 frcm twice weekly* to weekl,7 and
add of rrcn=tcr_rg recuirements for waste streau:s OOla
Oveekiv grab), 001b 2r_c' 002a (grab before each batch
eischarge) oral 001c ( twice monthl-,) . DEC or --,poses 'that all
new/revised effluent limitationsand meri_oring recuirements
take Prsect 4=Iediateiy upor the effective date o; the
renewal permit.
3

Cor. Edison's position with regard zo DEC's proposed Ph
requi.romer.ts is summarized below:
o Effluer.t liir taticr.s and/or m-Oni torirg teauiremPr.ts for pF
in internal waste Vtreams 001a, 001b, Mc, 002a or arsy
other internal 'waste stream carnet legally be imposed ir.
the final pe=it.
o There is rc environmental justific,ati=on for a pH lit;it can
internal waste Streams. Effluent limits on internal waste
streams are redundar;t and unnecessary since the currrr.t PP
'-_r-it of 6.0-9.0 at the point of discharge to the public
receiving water provides aGequate protection of water
ruality. Furthermore, a PH limit of 6.0-9.0 has bEer.
�eerted acceptable by DEC at the point of discharge.
o T':e costs to achieve a pF !_mit of 6.0-9.0 or. internal
waste strei�;.m-s ,,-culd be wholly disproportionate to anv
limited effluent reducticr. ar..d' environmental ben: -Nits to
be derived.
o Even if it were ever_tually deters:.ined that pE Emits rna�-
legall:7 be imposed -for waste streeims.001a, 001b, 001c and
002a ('which for the reasons set' forth in these -ce-aments
cannot be the case) , in order to achietae
consistenc- with! the limit of 6.0-9.0 at Discharge 001,
such limitations must be less stringent then a range of
6.0-9.0 (applied at the point o` d'_scharge), .n order to
take `u11;7 into account pH adjustment within the
discharge turnels ; and
c A compliance schedule to rrpet pE. lir"i is on internal waste
streams reed nct be provided i` ss:.ch 1=r -its are not
ultimatel•7 imposed, Even if it were e,:ertuall,-
determirle.0 that pP 7.`-tsits or. irre=nal *paste rtrea.ns may
legal!- be ir,posed, a reasonable ccmpliance schedule must
be provided to install equirr-pnt r;ecessar;7 to achieve
such limitations before thev become effective.
The SllUDgrr_ `or this position is as fol'_o4ls:
(a) Effluent Limitaticr.s anal/or t-'crit_orin Aocuireme_ts for oF.
in
:V -.tern 7�7E ste
r'ilSCreamS (iia U�l'�!:ca or nv
Other iriterra.l i�laste Stream Carrot Leal'.•- be Impose
(1) The Clezr. -Tater Act ?,_snits the authority under Sectio::
402 to controlling the add' tiOr. of pollutants to
na-%74gable waters through point source discharges
(Secti.or.s 301 and 402 and definitions specified in
Secticr. 502, Paragraphs (l),(7),(11),(12) ard`(16)).
Based or. -rose sections, e:fluPnt 14 `tatier's can or.! -,-
be applies at the point
the effluent enters the
receiving waters, except by the consent of the
permittee. Therefore, the point of discharge into
4

navigable waters fcr Discharges 001 and 002 Ord 003)
at the Station is at the confluence of the end of the
discharge_ tunnels and the East River.
(2) E?A`s RIMS (Decar.solidated) E?egulaticrs (40 CFR 122)
?ssentially track the authority specified under Sectior.
402 and require effluent l imit2-tions to be set at the
point of discharge to navigable waters. Section
122.45(a) states that all permit effluent limitMticr.s
shall be established for "each outfall or discharge
point of the permitted facility" except as otherwise
provided in Section 122.45(i).' Section 122.45(i)(1)
states that ?units on internal *caste streams ma-7 be
imposed in encepticr.�-al cases and cr.ly if 14-m4 tations at
the outfall are impractical or infeasible. Sectior.
12.2.45(i)(2) states that limits on internal waste
streays may be impcsee. only when the Fact Sheet under
Section 40 CFF. 124.56 sets forth the e:.cepticral
circumstances which make such Junir­jti_ons necessary,
such as when the final discharge -point is inaccessible,
the wastes are so diluted as to make monitorirg
impracticable or the interference of pollutants at the
point of discharge `:vould make detection_ or' analysis
impracticable. Beth Sections 122.45•• and 124.56 ware
applicable to State programs.
Based on these regulations, there car, be ro exceptional
circumstance Justification for impesition of pH limits
ar-d/or monitoring requirements or, internal waste
streams unless the final. discharge point is
inaccessible for sampling. Y onitoring (detection ar.c
analysis) for pR (unlike pot utants measured in te.rr.s
of mass or concer:tration, such as heawy rtet`'s) is r.ct
impractical at the point of cischaree due to dilution_
or interference. 'Based cn the distinction between the
nature 'and monitoring o` p?' er.d other pollutants, Cern
Edison has accepted internal limits or. other ,pollutants
in some cases ( even though we belf eve that sucl l.jmi-ts
carrot lPga?'_; be unposed based cr. the Clean 'Fater Act
and State Entiirormer.tel Conservation. Law) since in
thcse cases we recognize the impracticalit;T oz
deterr..ir.ing compliance with effluent ' lim-tations fc
such pcll.utants at the ::i^al disc::arge (see Section 2.
of these cor,r_er.ts) . Such I.mpracticality, , howe-:Pr, does
not ann!" tc PF.
i-- —. regard to rhe sues*._cr of sampli.rg pointe, -pF
saMples TAT DiSC176rres 001 are QC-' are currentlt taker -
in the discharge plume oft the dock rather than
directly ir_ �.he discharge tunnels, since-h-sical
access to the tturrels is currently unavailable i.e. the
discharge turneis ter -*irate under the FER, Drive, about
60 feet from the enc'_ of the dock. However, C,cr. Edison_
will create sampling access points ir. the Discharge 001

and 002 -discharge tunnels by June 1, 1985, or by the
beginnirrg of the 1985 chlorination seaser, at Waterside,
whichever is later, es part of our chlorine compliance
prcgrarm (see comments ccr..cerning proposed chlorine
requirements, Section 4 (c)) . Therefore, there is no
ustificaticr_ :dor internal waste stream pF? limits based
on Section 122.45. —
(3) Title 8, Art?.cle 17 of the New York State Environmental
Con servat4 or Law (EC?-) requires permits for the
discharge of polluter.ts frons ary cutlet or pcirt source
to the waters of the state (Section 17-0803). The ECL
clear1 y, limits DEC's authoritn to Controlling
pollutants at the point such effluents enter the
receivirg waters (Sections 17-0803, 17-0509 and the
definitiozs specified in 17-0105, Paragraphs
t2),(11),(15) and (16)), This limitation is reir�torced
by the SPDES regulations implementing the ECL (6 r.YCFR
Parts 750-757). Although we believe that the EC;
Limits DEC•'s authority to impose effluent limits at the
final discharge, Ccn Edison, has accepted and will
cer_tirue to accept internal waste stream limits for
pollutants other than pR where we believe con -pi arse
monitoring at the final d4scharge point is impractical,
the limitations are reasonable and not more stringent
than required b; appropriate regulations. This is
clearl-7 not the case for vi-.
(4) EPA Pest Practicable Technology (BPT) regulatior_s limit
the pF of all discharzes froti. steam electric poser
Plants, e::cept once through cooling water, to a r.7rge
of 6.0-9.0 (40 CFR 423.12(b)(1); emphasis ,deed).
EPA.'- csrrer•t Effluent Limitation Guidelines fcr pE (47
FR 5'30_, Fovember 19, 1982) are ,dentical to those
contained in the ir.it4ell., promulgated Cu;delir_es
published ir: the Federal Fegis*_er cn October a 1974
(39 sP. 36166). in both the original and revised
Guidelines, no pH. limitations are explicij-tiy places? or.
any inter, a! we.sre. streams. eased on the definit4 ons
specified in the Clear. Water Act, tbe EPA lirr:itation of
6.0-9.0 would apply or-!-- at the outlets of the
discharge tunnels to the East River and not tc ani
:rte`-r.ai waste stream.
BV letter dated May 3, 1004 (attacF-.mert to E_c:jlhi: 1),
Car, Edison fermall­ reauested that the U. S.
E'rvi.rcrmental Protection Aser:cv, (EPA) clarify i'ts BrT
and internal ctiastP stream regufaticns es thev apply to
PH. At a r.:eeting helc' cn August 10, 1984 between Ccn
Edisor, and EPA., the Preens-* stated that it would take
z.beut ore r:or.th to review the rulemaking record and
infr_rr Con Edison and DEC of its determination.
�, .- tip,_ cz,_, r?at-ad December 13, 1982, DEC states

(b)
that internal waste stream monitoring is proposed for
specific low volume *wastewaters since compliar_c¢ with
applicaTrle 11mi,tations cannot be. determined at the
final discharge. For the fcllowing reasons, this
explar_ation aces rot satisfy Federal (40 CFR 1.4.56)
and State (6 IPICRR 753.3) regulations, which require
that Fact Sheets set fort" tire. _legal and technical
baiis of proposed limitations:
(a) The Fact Sheet does not specifically address the
rationale for the proposed pH limits. lr. fact, it
cannot be determined from the Fact Sheet_ to which
waste streets em pollutants the e7.pIanation
prclr^ded in the Fact Sheet applies;
(b) The Fact Sheet does not e-pecify whether the
proposed pH limits are based cn EPA's Guidelines
for Steam Electric Pcwer Plants or DEC's Best
Professional Judgement (BPJ) determination of Best
Practicable Technology (EPT) or Best Converrtional
Technology (BCT), or any other basis;
i. Tf the proposed limit
Guidelines, it does
interprets the 6.0-9.0
internal waste streams
for that intepretatior,
is based on EPA's
not specify whether DFC
RPT pu.7.imit to apply to
(ard i5 so, the reasons
or to final discharges;
2. if the proposed limit is based or. BPJ, it does
riot address the factors specified in Section 304
of the Clear. Water Act or 40 C:'P_ 125.: (See
Paragraph 3.(d) of these comments);
(c) The Fact Sheet rices not specif-y which sections cf
the Clear. Water Act err State Ervirormental
Conservation Law. provide DEC with the authority to
i=ose internal waste strepm limits for pF. Nor
does it specify the sectio*ls of EPA. and DEC
regulatior_s which authcrize such 1 _nits ; ar.d
(d) The Fact Sheet does not specif•� which of the
exceptional circumstanced specified in 40 CFR
122.45(1) , if any, it relied on tc reach the snated
cene?usior. that compl'_asce with the 6.0-9.0 pF
1 --citation cannot be deta=ined by monitoring at
the final discharge.
There is Yo Environmental Justi`icatien for rF. limits cr.
Irternal Weter Streams
The current pH limitation_ of 6.0-9.0 at Discharges 001 arc'.
002 affords adeauate prctectior_ of public receivire water
quzlitf. A PH limit of 6.0-9.0 at the point or d� scharge
w, -s 6eered acceptable b-,? EPA. Region 1I (and DEC t7z its

Section 401 Certification) in the initial discharge permit
issued by F,egion II on november 30, 1974, as well as by DEC
(aid Region II ir, its overview capacity) in the renewal
Permit issued by DEC on July 1, 1980. Beth the inir.;zi and
renewal permits were be.SEd on EPA's Effluent Guidelines
promulgated cn October 8, 1974 and were to ha,re included ary
more stringent water cuality-based--requirements. Sir_ce
applicable Effluent Guidelines for pH have not changed sir.ce
initial permit issuance and DEC has not shown that a final
discharge pl' within the range of 6.0-9,0 has caused or will
cause any adverse environmental impacts, there is no basis
for imposition of more stringent PH limitations in the
renewal permit. In addition, b,- proposing to maintain_ the
current 6.0-9.0 PH limitation for Discharge 002, DEC has
deemed that range acceptable at the point of discharge.
Furthermore, installation of a waste neutralization system,
which *could by required to meet the proposed limits, would
result in the addition of significart amounts of
neutralizing chemicals (acid/caustic), thereby increasing
the amount of pollutants discharged.
(c) The Cost
To Be
o Achieve Internal Waste Stream pR Limits Is
ropertionate To The Effluent Pe uction Benerits
The Waterside Station has two demineralization systems,
which are housed in separate buildings. In order to achieve
the proposed pH limits for demineralizer regeneration waste
streams (001b and 002a),. installation of two waste
neutralization systems would be required due to the physical
layout of the facility and the relatively large number of
regenerations performed (See SPDES Application Update for
more detailed information cercerrirg rege eratior_ waste
streams). Each s;Tstem would consist o 1-2 large
reutre.l_zatior. tank,, pumps, acid and caustic injection
s,: stems, instrumentation and cor.tro'_s Grd an elaborate
piping system. Con Edison. ccnservat'Vel^ 'estirre.tes the
total capital cost of these s, -stems to be' $3-5 tillicr., a
reasonable estimate taking into acccunt the r_ature of the
fe.ci lity ( primarilY stent: send.cut) , age of the faci lity, its
ph,?sical layout and space Iiriitat4ons, and i -he relativelylarge number of reger_eratiors (Guo to steam ser.dout). These
costs would ir.crDzse substantially if a. PF limit e 6.0-9.0
is irmpased for boiler blcwdoh-r. (001a; and 0022 ir. current
permit) , wb' cb tvpi ca?'-�� has a p?E of 10-10, 5. In additicr, ,
s-ubstantial cperat?ng crets (labor ar.d chemicals) would be
incurred. These capital and operating costs- would
r
ultia`_'el be borne by Con E'disgr's steam and electric
ratepayers. r
As stated above, Con Edsor believes that there is ro
environmental justification For a pF iii -it of 6.0-9.0 or.
ir_terr,al waste streams. Such lim=ts wculd result in little,
r
=-1 unv, enyirormental benefits, which are wholly

disproportionate to the costs that would be borne by Cot?
Edison and` its ratepayers. As specified abo,re, such
reeuiremer.ts would, in fact, result ir_ the discharge or
increased atrour_t of pollutants.
(d)
if It Vere Eventually To Be Determined That i Linits :fav
Le al y Be imposes For internal -Waste Streams Such
i.i_mitations 11ust be Less Strinsent tFian -
The existing pV limits of 6.0-9.0 for Discharges 001 and 002
reflect Pest Practicable Control Technology Currently
Available (BPT) as defined by EPA (40 CFR 423.1h(b)(1)). Ey
limiting the pH cf internal waste streams to that same
range, DEC is, in effect, proposing a 14 -mit more strir.gert
than BPT. Section 301(b)(2)(E) of the Clean Water Act
provides for rrore stringent limits then BPT for pE and other
conventional pollutants by application_ of the Pest
Conventional Pollutant Control Technolog. (PCT), EPA has
deferred promulgation of ECT limitations for power plants
pending promulgation of a revised BCT methodology.
Therefore, any BCT limits imposed -in a power plant permit
must be developed on a case-by-case basis, pursuant to
Secten 402(a)(1) of the Clean tdater Act and Article 17,
Title 8 of the State Ervirormental Conservation. i.aw.
The proposed internal waste stream l-mitatior. of 6.0-9.0
rust accordingly be based on a case.-bv-case determination cf
BCT by DEC. EPA regulations (40 CFR 1?5.3(c.)) allow the
imposition_ of technolog7 based limitations to the e:ztent
FPA -promulgated effluent guidelines are inapplicable. In
these cases, the permitissuing authority (DEC) is required
to apply the appropriate factors speci fl ed ir. Secticr•. 304(b)
of the Clear. Water Act. For de•:elcP=er.t of ECT
limitations, the factors specified in Section 304(b)(4)(B)
must be ap-pned. These factorsinclude "the reasonableness
of the relationship between the r_csts of attair_in& a
reduction in effluent and the e=fluent reduction. bere_its
derived, and. the comparison of the cost and level of
reduction: of such pcl?uta.r.t from publicly ot;r;ed treatment
works to the cost and le -e' of reduction of such pollutants
`-Tore a class of category of industrial source" ar.c' "the age
o= equipment and _`acilit:es involved., the process emplcyed,
the engineering aspects of the application of various t• pes
of control techniques, process changes, non -easter quality
environmental 4.m-oacts (including energy re-quirements).6
Case-by-case limits trust_ also consider rhe. appropriate
techrclogy for the applicant's industrial_ categor;* zrd any
unique factors relating to the facili ►.;• (40 CFR
125.3(c)(2)). These factors must be considered regardless
of the permit issuir_g authorit.­ (40 CFR 125.3 (c)).
Or -ovember 18, 1982, EPA proposed to revise 40 CFF 124.56
end 40 CFP. 125.3 to explicitly specify the statutory and
�t�,or Fnrrnrs that rrust be considered in setting

case-by-case, Best Professional Judgement (BPJ) limits and -
the information that must be ircluded in the Fact Sheet (47
YR 52072),I_ The preamble to the proposed regulations states
that "Section 125.3(c)(2) already requires permit writers to
consider "statutory `'actors" i.n issuing EPJ permits, Eo
these changes simply clarify an. e -Fisting requirement." (47
FR 52080). The propcsed regulations,: therefore, would make
explicit what is already required, namely the application of
the statutory factors and any other factors considered in
the determination of BPJ limits and the inclusion in, the
Fact Sheet of any analysis of the application of these
factors and identification of anrguidar_ce cr other
docut.ents relied upon ir. setting the limits.
DEC has not provided Con Edison with ar_y documentation cF
its consideration of the factors specified in Secticn
304(b)(4)(B) apd 40 CFR 125.3(c)(2) in its development of
the proposed ECT limits for pH. Therefore, DEC ce.r.rot at
this time impose BCT limitatiors more stringent than BPT.
Even if it should ultimatel;> be determined that DEC may
impc-se pH limits en internal waste streams, which for the
reasons set forth hereir_ we submit it car.r.ot lawfully* ec,
then such limitations trust be less stringgent than 6.0-4.0 so
as not to be ir_ conflict with a 6.0-9 . C limitation at the
point of discharge. Otherwise, the ir.ter-ral limitations
would be more stringent that EPT and must be justified
taking into account the factors specified above.
(e) Even If it Were Eventually To Be •Determired That pH Lir"its
iIat Leaall,,, Be lm os ed FC; Tn.ternE T':£Ste °treame, A.
PeasoraFie omAliance Sche?ule oust e. Provided
If it were to eventually be determi.red that PH limits may
ee-ally be imposed or internal waste streams and such
Iimitations were ir_•pcsed, a reasonable schedule of
compliance would need to be provided in order to permit
procuremert and installation cf r_ecessa.r^ equipment before
such limits become effecti��e ,
DEC's propcsed corr_pl arse deadl:.ne (ef-fective date of the
rer.e-
wal oersit) is both arbitrary ar.c impossible to achieve.
Although DEC has nct provided i,ts rationale fcr the proposed
compliance de2dlire, we presume that =.t was based cr_ rh6 BCT
deadl_re of JuJI7 1, 1584 specifier'. in Secticr. 301(b) (.2) (E)
of the Cle<n [Nater Act, uc=•7ever, s=.ce DEC's prcpnsed
limits carrct legell,, be imposed under RCT as discussed
pre-.iously, t: e July 1984 deadline e..ces not apply.
rl the proposed urreaccr_able and imaracticablp ccmpliar.ce
deadline verp to be euer.tually imposed, Cor. Edison, would
ur�airly be put in the ur_ter Ale Position of i=ediately
�y olatirg the permit. For purposes of fraying the issues
for consideration in a hearing, any perm -t issued b -r DEC

containing pN limits on internal waste streams should
contain a realistic compliance schedule, to be subsequently
agreed upcm, which would encompass time periods recessar;,
for the procurement and installation of necessary equipment.
(f) Monitorin P.eauiremerts
Monitoring requirements for pH carrot legally be imposed for
irterral waste steams for the reasons stated herein. If it
were eventuall•7 to be deter>tined that pH monitoring
reGuirercents may legally be imposed on ir.te�,al WeEres
streams, monitoring re.auiretrents for those waste screams
:1:Culd not be required prior to a realistic compl;ar:ce
deadlira eventuall- agreed uper (see paragraph (e) abo-ire),
since the limitations would not be effective until that
titre. We czrnot currently comply with the proposed
requir¢ment of taking grpb sat:ples before each batch
discharge of detrir.era.li4er regeneration wastes (001b and
002a), since there is no prop*.sion for ho' --ding up these
wastes prior to discharge: 'Even if neutralization s -,,,stems
are installed, this proposed requirement may be
impracticable, if the systems are designed for
semi -continuous operation in which, when the e'_`fluent is
within the set pH range, discharge may occur m9n-y times over
a regeneratier cycle.
In suunary, effluent limitations and monitoring requirements
`or pH should not be Imposed for internal waste streams for the
reasons specified above. The only pN limits that may be imposed
are the current BPT permit limitations of 5.0-9.0 at Discharges
001 and 002 (and 003) . This approach woulc be ccnsistert with
that recommended by DEC in its Division. of Water Guidance
memorandum No. 04--W-33- ("UJ ifethodologies - Guidance for the
Application of Pest Professional Judgerent (BP.) in D?terminir_g
MES CcT.eitior_s," dated April 1983), which states (Section
VIII.E.)s
"!,,'ith r-aard to cor.,ventional pollutants, the Departcerr_
will generally consider APT ar. acceptable level of
cor.trcl, unless effluent guidelines or hater Quality
recess tate more stringent control."
Since efflLPnt- gt_idelines mandate z pP limit of 6.0-9.0 at the
poir..t of discharge and water cuolit-1� has rot been shorXT to
necessitate arr.- rcre stringent limits, the current limits are
ppprcpriate and should be mair.ta'_red. DEC mai- -not impose a
Particular techrologv fcr treetirg SITES Limits. Trerefoze, Gcr
Edison should be free to meet those limitat_cns by the method of
ou: choice.
Ever. if DEC could legrliy impose pH limita_t'ons for internal
waste strears at this facil: t3 , a compliance schedule would be
reUuired to achieve such limitations. in addition,
notwithstardir.g the legal arguments against impositicr. of pH

G
requirements for internal waste streams, DEC must provide the
legal and technical basis, inclueing any supporting
dccumer.taticn, --£er any such requirements prior to their
establishment 4-P.2. final per -r -it. Ir'such rationale is eventuz?Iv
prc,Tided, Cor, Ed4son must be given a rea.sorable cppertunity for
eva-luaticn and submission of ccmr.ents.
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