NC0051373_Staff Comments_20121030

Division of Water Quality
October 30, 2012
To: Water Treatment Plant Workgroup and NPDES Permitting Unit
From: Cindy A. Moore, Aquatic Toxicology Unit
Carol Hollenkamp, Aquatic Toxicology Unlof ff
Subject: Changes to the Toxicity Testing Requirements in the Water Treatment Plant Permitting Strategy
(October 2009)
The Aquatic Toxicology Unit (ATU) recommends assigning acute 48 hour Ceriodaphnia dubia Pass/Fail testing at 90%
for water treatment plants (WTP) that have an Instream Waste Concentration (IWC) 2: 0.25% but discharge at a
frequency and duration that do not enable chronic sampling according to either the North Carolina Ceriodaphnia
Chronic Whole Effluent Toxicity Procedure or according to Section 8.3, in ERA-821-R-02-013. This assignment would
only be approved for WTPs, after it has been determined that the normal, operational discharge of the facility does
not enable chronic sampling. Suggested permit language is provided on page 3. An updated Table 5.2 of the Water
Treatment Plant Permitting Strategy (October 2009) is provided below. Alternate test assignments, such as the
application of an acute to chronic ratio in the situation of small IWCs, may be considered on a case by case basis
depending on the specific characteristics of the facility's discharge and receiving stream. Any alternate test
assignments must be approved by ATU. If you have any questions, please contact Cindy Moore or Carol
Hollenkamp.
Potential Replacement Table for Table 5.2 in the Water Treatment Plant Permitting Strategy (October 2009):
01scharl a Conditions
Test
Dilution
JWC < 0.25% or IWC incalculable
Acute 24-hr Pass/Fail at 90%
IWC 2! 0.25%
Chronic test at IWC (maximum 90%)
Tidal Effects
Modeled Tidal Discharge
Chronic test at chronic mixing zone characteristics
Tidal Discharge -Not -modeled
Acute 24-hr Pass/Fail at 90%
Receiving Water Type
Freshwater
Acute test organism: Pimephales promelas (Fathead minnow)
Chronic test organism. Ceriodaphnia dubia
Saltwater
Acute test organism: Mysidopsis bahia (Mysid shrimp)
Chronic test organism: Mysidopsis bohio (Mysid shrimp)
1 USEPA. 1991. Technical Support Document for Water Quality -based Toxics Control. EPA/505/2-90-001. pp 56-58.
2If discharge is to a lake or lake arm where 7Q10 estimate is not meaningful, the IWC will be incalculable.
3if the facility's regular operational discharge is at a frequency and duration that do not enable chronic sampling, acute 48-hr
Ceriodaphnia Pass/fail at 90% may be assigned. This will revert to a chronic testing assignment if it is determined by DWQ that a
chronic schedule can be met.
°For saltwater classified streams, a fathead minnow may be assigned for acute tests if the salinity of the receiving stream at the point of
discharge is <5 ppt throughout the tidally influenced cycle.
Rationale
Water Treatment Plant (WTP) discharge schedules are dependent on the demand for drinking water and are often
more irregular, less frequent and less consistent than Waste Water Treatment Plant (WWTP) discharge schedules.
Per the DWQ WET Strategy Memo (August 2, 1999) and EPA guidance in the Technical Support Document for
Water Quality -based Toxics Control (TSD), facilities with an IWC > 0.25% should be assigned chronic testing. In
some situations, sampling a WTP discharge to meet a chronic testing schedule may not be possible. If a WTP
discharges only once a week, they will not be able to meet a chronic toxicity sampling schedule. If a WTP discharges
twice a week, they will need to discharge on a Tuesday and Thursday to meet North Carolina's Ceriodaphnia Chronic
Whole Effluent sampling schedule. Alternatively, they would need to discharge 2 days a week, at approximately 48
hours apart, and hire a NC certified laboratory to perform a specialized testing schedule that would be markedly
different than the laboratory's regular testing schedule for NC Chronic Tests. in order to meet EPA's testing
schedule, they would need to discharge 3 times a week, with the discharges spaced approximately 48 hours apart.
Therefore, WTP's that discharge at a frequency and duration that do not enable chronic sampling according to
either the North Carolina's Ceriodaphnia Chronic Whole Effluent Toxicity Procedure or Section 8.3 in EPA-821-R-02-
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Aquatic Toxicology Unit Environmental Sciences Section

013 will either 1.) simply not be able to perform a chronic test; or 2.)
in attempting to meet a chronic test schedule
ular operation would require modification and potentially
Fail testing at 9©%o effluent.e undue financial burden.
acute
hese
the facility's reg p
cases, ATU recommends assigning an acute 48 hour Ceriodaphnia
n acute testing assignment in this situation is similar to the
ss fail test assignment at 90'% effluent and 48 hour® duration is the most stringent of the acute testing
as / protocol. The use
assignments under North Carolina p
application of acute to chronic ratio in the situation oft
application of an acute pass/fail test assignment at 90% when the ins#ream+ Waste Concentration (IW discharge
incalculable. Alternate test assignments, such as the
may be considered on a case by case basis depending on the specific characteristics
TU cteristics of the facility's
lwcs,
and
Y
and receiving stream. Any alternate test assignments must be approvedears to
unique to North Carolina. Both Florida and Coloraed or
The need for a modified testing assignment for facilities that cannot meet a chronic discharge schedule appears
be limited to WTPs at this point. however, this need +s n
e. This testing assignment is not specific to WTPs term intermittent
have Ditties which specify acute testing assignments f situations where chronic test schedules cannot+n
ha p
either of
# states: facilities with when the discharge is not considered a chronic expos ) s Section 8.3, in Methods EPA-821-
these state policies. The Florida Administrative Code, Chapter 62-620.620rding to (3) () n with 1Met effluent and
ng accO
discharges at frequencies and durations4 shall be equi ed t conductacuteacute definitive tests
ta 6 0(with F.A.C. Chronic
R-02-013 and EPA-821-R-02 Olffluent
using a minimum of five dilution concentrations in accordance with Cont ap
shall not be required." The Colorado Water he discharge is intermittent, a+ definedhole E
below, acute
definitive tests states: Where the d g
Toxicity (WET) testing Section III, Part 2 (c), The basis for this is that there would not be chronic
WET testing may be substituted for chronic WET testing.
n 3 i s per 7 day period, and Tess than 10 days
aquatic life to the effluent". Definitions of Intermittent Di �harges include: "A) the maximum discharge
exposure of aq and less than
frequency is less than 3 consecutive days (72 hours), is less than 5 consecutive days (120 hours) and less
total per month"; and " B) the maximum discharge frequency
than 5 total days per month."
daphnia testing for WTPs that
in summary, AT considers the assignment ofule as t e mcute ost protective stil 48 hour ep North Carolina can take while testing
DTP
cannot meet a chronic testing sampling sched
he last decade, so the need for an alternative testig of ng
a assignment
and
sampling a facility as close to its normal operational schedule as possible. The inclusion of toxicityn permit
p process that has evolved over
permits has been a
was not needed p that a 1NTP discharge schedule can support chronic test sampling.
previously. DWQ will includee language in the permit that will enable a re open
assignment of chronic testing i# it determine
Refer e5: " pctober 2009).
Changes to DWQ Water Treatment Plant (WTP) Permitting Strategy
htt ortal.ncdenr.or web w ess atu downloads
Toxicity {WET) Testing. Effective September 30, 2010.
er Pollution Control Program Policy for Whole Effluent ToYic'+ty Testing. implementation of the Narrative
Colorado Wat Whole Effluen
Standard For Toxicity in Discharge Permits Using
htt www.colcrado. ov
Memo. August 2,1999. htt : ortal.ncdenr.or web w ess atu ownloa s
DWQ WET Strategy 2002. Short Term Methods for Estimating the Chronic
EPA 821-R-02-013. United States Environments! Protection Agency. ds for the Chronic
Toxicity of Effluents and Receiving Waters to Freshwater organisms. Fourth Edition. 350 PP.
-R-02-014. United States Environmental protection StAge Agency.
Organisms. Fourth Edition. 350 PP.Estimating
hort Term Metho
EPA 821 Whole
Toxicity of Effluents and Receiving Waters to Marine an E
Chapter 62-620.620, Guidelines for Establishing Specific Permit Conditions, (3)
Florida Administrative Code, Chap
waves forlEstoblishi g Specific
Permp?id=62-620.620
Effluent Toxicity Testing. Effective 4/02/2008. https://www.firuies,org/gateway/ruieno.asp
h Carolina Ceriodophnia Chronic Whole EffluentToxicity Procedure. Version 3.0. December 2010.
s atu ownloads
h ortal.ncdenr. - web w es
U5EPA. 1991. Te
chnical Support Document for Water Quality -based Toxics Control. Office of Water. Washington, D .
EPA/505/2-90-001.
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Environmental Sciences Section
Aquatic Toxicology Unit

ACUTE TOXICITY PASS/FAIL MONITORING FOR WATER TREATMENT PLAINTS (QUARTERLY)
The permittee shall conduct acute toxicity tests on a quarterlh basis using protocols defined in the North Carolina
Procedure Document entitled "Pass/Fail Methodology For Determining Acute Toxicity in A Single Effluent Concentration"
(Revised December 2010 or subsequent versions). The monitoring shall be performed as a Ceriodaphnia duhia 48 hour
static test. The effluent concentration at which there may be at no time significant acute mortality is 90% (defined as
treatment two in the procedure document). Effluent samples for self -monitoring purposes must be obtained during
representative effluent discharge below all waste treatment. The tests will be performed during the months of ,
and These months signify the first month of each three month toxicity testing quarter assigned to the
facility.
All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge Monitoring
Form (MR-1) for the month in which it was performed, using the parameter code TGA3B. Additionally, DWQ Form AT-
2 (original) is to be sent to the following address:
Attention: North Carolina Division of Water Quality
Environmental Sciences Section
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Section no later than 30 days after
the end of the reporting period for which the report is made.
Test data shall be complete and accurate and include all supporting chemical/physical measurements performed in
association with the toxicity tests, as well as all dose/response data. Total residual chlorine of the effluent toxicity sample
must be measured and reported if chlorine is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the
permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the facility name,
permit number, pipe number, county, and the month/year of the report with the notation of No Flow" in the comment area
of the form. The report shall be submitted to the Environmental Sciences Section at the address cited above.
Should. the permittee fail to monitor during a month in which toxicity monitoring is required, then monthly monitoring will
begin immediately. Upon submission of a valid test, this monthly test requirement will revert to quarterly in the months
specified above. Assessment of toxicity compliance is based on the toxicity testing quarter, which is the three month time
interval that begins on the first day of the month. in which toxicity testing is required by this permit and continues until the
final day of the third month.
Should any test data from either these monitoring requirements or tests performed by the North Carolina Division of Water
Quality indicate potential impacts to the receiving stream, this permit may be re -opened and modified to include alternate
monitoring requirements or limits.
Should it be determined by the North Carolina Division of Water Quality that the facility's discharge frequency and
duration enable chronic sampling according to either the North Carolina Ceriodaphnia Chronic Whole Effluent Toxicity
Procedure or to Section 8.3, in Methods EPA-821-R-02-013, the permit may be re -opened and modified to include chronic
toxicity tests.
If the Permittee monitors any pollutant more frequently than required by this permit, the results of such monitoring shall be
included in the calculation & reporting of the data submitted on the DMR & all AT Forms submitted.
NOTE; Failure to achieve test conditions as specified in the cited document, such as minimum control organism survival
and appropriate environmental controls, shall constitute an invalid test and will require immediate follow-up testing to be
completed no later than the last day of the month following the month of the initial monitoring.
Alt Chronic PIF Cerio 48 ATG version 10112
Alternate Acute Assignment for WTPs

Division of Water Quality
June 11, 2012
Pu0-m►
To: Water Treatment Plant Workgroup
From: Cindy A. Moore, Supervisor, Aquatic Toxicology Unit e �'
Through: Jay SauV'e"6n Chief, Environmental Sciences Section
Subject: Changes to the Toxicity Testing Requirements in the Water Treatment Plant Permitting Strategy (October 2009)
The Aquatic Toxicology Unit (ATU) recommends the following changes to the toxicity testing requirements for the Water
Treatment Plant Permitting Strategy (October, 2009): 1.) Select Mysidopsis bahia as the testing species for acute discharges to
saltwater classified streams; 2.) Remove the language that allows a permittee's choice between fathead minnows, mysid
shrimp, or silverside minnows for acute test organism; 3.) Insert language in the permit that describes a permittee's options
for alternate test species selection.
Per EPA guidance, the most sensitive species should be chosen when testing only one species (USEPA 1991). Although no
species is always the most sensitive to all toxicants, Mysidopsis bahia has been documented to show a greater sensitivity to
ion toxicity than other saltwater test species (Pillard et al. 2000). Therefore, Mysidopsis bahia has been selected as the
primary testing species for acute discharges to saltwater classified streams. However, permittees have the option to select an
alternate test organism that provides an equal or greater level of protection. This option is described below. Suggested
permit language and references are included on page 2.
Potential Replacement Table for Table 5.2 in the Water Treatment Plant Permitting Strategy (October 2009):
Dischaq
a conditions
I Test
Dilution
IWC < 0.25% or IWC incalculable
Acute 24-hr Pass/Fail at 90%
IWC 2 0.25%
Chronic test at IWC (maximum 90%)
Tidal Effects
Modeled Tidal Discharge
Chronic test at chronic mixing zone characteristics
Tidal Discharge -Not -modeled
Acute 24-hr Pass/Fail at 90%
Receiving Water Type
Freshwater
Acute test organism: Pimephales promelas (Fathead minnow)
Chronic test organism: Ceriodaphnia dubia
Saltwater
Acute test organism: Mysidopsis bahia (Mysid shrimp)
Chronic test organism: Mysidopsis bahia (Mysid shrimp)
`If discharge is to a lake or lake arm where 7Q10 estimate is not meaningful, the IWC will be incalculabie.
2For saltwater classified streams, a fathead minnow may be assigned for acute tests if the salinity of the receiving stream at the point of discharge
is <5 ppt throughout the tidally influenced cycle.
Permittees with acute toxicity testing requirements discharging to either freshwater or saltwater receiving streams may request the
use of a test organism other than that specified by the permit upon documentation that the alternate test organism provides an
equal or greater level of protection and is appropriate based on the characteristics of the discharge and receiving stream. Such
documentation would consist of one of the following:
1. .For saltwater classified streams, a fathead minnow may be assigned as the acute testing species if the salinity of the
receiving stream at the point of discharge is <5 ppt throughout the tidally influenced cycle. This determination may be
based on the best professional judgment of DWQ staff or data collection provided by the permittee and approved by DWQ
staff. This evaluation should include vertical profiles of salinity/conductivity measurements at both high tide and low tide
over several 24 hr cycles.
2. Three consecutive "side -by -side" tests with results indicating that the alternate test organism is as or more sensitive to the
facility's effluent. Each test series would consist of two separate toxicity tests conducted on the same sample of effluent
with the length of exposure specified by the permit, the only difference between the tests being the organism used.
3. An alternate plan developed by the permittee and approved by the Aquatic Toxicology Unit that demonstrates an equal
level of protection is offered by the test organism.
For items 2 and 3, it must also be demonstrated that viable and standardized culture techniques are available for that organism and
standardized testing methodologies have been developed and validated. This demonstration should meet guidance provided by EPA
in Section 6 of EPA-821-R-02-012.
Page 1 of 2
Aquatic Toxicology Unit Environmental Sciences Section

Suggested Permit language for Acute Discharges to Saltwater Classified Streams
For footnote to the Table of Effluent Limitations and Monitoring Requirements:
Acute Toxicity 24-hr Pass/Fail Monitoring: (name months). Permittee shall use mysid shrimp as the test organism unless another
organism of equal or greater sensitivity is deemed more appropriate based on the characteristics of the discharge and receiving
stream. See Special condition A () for details.
For Special Conditions Section
A O Acute Toxicity Pass/Fail Monitoring (Qrtrly)
The permittee shall conduct acute toxicity tests on a quarterly basis using protocols defined in the North Carolina Procedure
Document entitled "Pass/Fail Methodology for Determining Acute Toxicity In a Single Effluent Concentration" (Revised December
2010 or subsequent versions). The monitoring shall be performed as a Mysidopsis bahia 24-hour static test. The effluent
concentration defined as treatment two in the procedure will be 90%. The permittee may request the use of a different test
organism upon documentation that the alternate test organism would provide an equal or greater level of protection and is
appropriate based on the characteristics of the discharge and receiving stream. Such documentation would consist of one of the
following:
1. For saltwater classified streams, a fathead minnow may be assigned as the acute testing species if the salinity of the
receiving stream at the point of discharge is <5 ppt throughout the tidally influenced cycle. This determination may be
based on the best professional judgment of DWQ staff or data collection provided by the permittee and approved by DWQ
staff. This evaluation should include vertical profiles of salinity/conductivity measurements at both high tide and low tide
over several 24 hr cycles.
2. Three consecutive "side -by -side" tests with results indicating that the alternate test organism is as or more sensitive to the
facility's effluent. Each test series would consist of two separate toxicity tests conducted on the same sample of effluent
with the length of exposure specified by the permit, the only difference between the tests being the organism used.
3. An alternate plan developed by the permittee and approved by the Aquatic Toxicology Unit that demonstrates an equal
level of protection is offered by the test organism.
For items 2 and 3, it must also be demonstrated that viable and standardized culture techniques are available for that organism and
standardized testing methodologies have been developed and validated. This demonstration should meet guidance provided by EPA
in Section 6 of EPA-821-R-02-012, Short Term Methods for Estimating the AcuteToxicity of Effluents and Receiving Waters to
Freshwater Organisms, Fifth Edition, 2002.
References:
httn://Portal.nc4enr.org/web/wci/ess/atu/downloads:
"DWQ WET Strategy" (August 2,1999) & "Changes to DWQ Water Treatment Plant (WTP) Permitting Strategy" (October 2009)
Pillard DA, DuFresne DL, Caudle DD, Tietge JE, Evans JM, 2000. Predicting the toxicity of major ions in seawater to mysid shrimp
(Mysidopsis bahia), sheepshead minnow (Cyprinodon variegates), and inland silverside minnow (Menidia beryllina). Environ Toxicol
Chem 19: 183-191.
USEPA. 1991. Technical Support Document for Water Quality -based Toxics Control. Office of Water. Washington, DC. EPA/505/2-90-
001.
USEPA. 2002. Short Term Methods for Estimating the Acute Toxicity of Effluents and Receiving Waters to Freshwater Organisms.
Fifth Edition. EPA 821-R-02-012.
Page 2 of 2
Aquatic Toxicology Unit Environmental Sciences Section