Current through Register Vol. 48, No. 9, September 27, 2024
1. The General Assembly of South Carolina in
the Act has declared the following policy: "It is declared to be the public
policy of the State to maintain reasonable standards of purity of the air and
water resources of the State, consistent with the public health, safety and
welfare of its citizens, maximum employment, the industrial development of the
State, the propagation and protection of terrestrial and marine fauna and
flora, and the protection of physical property and other resources. It is
further declared that to secure these purposes and the enforcement of the
provisions of this Act, the Department of Health and Environmental Control
shall have authority to abate, control and prevent pollution."
2. The classes and standards described in
Sections G and H of this regulation implement the above State policy by
protecting the waters of South Carolina. Consistent with the above policy, the
Department adopts the following general standards in items 3-19 for all waters
of South Carolina.
3. No waters of
the State shall be used for the sole or principal purpose of transporting or
treating wastes.
4.
a.
Any discharge into waters of the State must be permitted by the
Department and receive a degree of treatment and/or control which shall produce
an effluent which is consistent with the Act, the Clean Water Act (P.L.
92-500, 95-217, 97-117, 100-4), this regulation,
and related regulations. No permit issued by the Department shall be
interpreted as creating any vested right in any person. Additionally, any
discharge into waters of the State containing sanitary wastes shall be
effectively disinfected as necessary to meet the appropriate standards of this
regulation. The Department may require best management practices (BMPs) for
control of stormwater runoff as part of the requirements of an NPDES permit, a
State construction permit, or a State 401 Water Quality Certification.
b. When not specifically covered
by permit reporting requirements, any unauthorized discharge into waters of the
State which may cause or contribute to an excursion of a water quality standard
must be reported by the responsible party to the Department orally within
twenty-four (24) hours of becoming aware of such conditions. Further, written
notification must be provided to the Department (Bureau of Water) within five
(5) calendar days of becoming aware of such conditions and the written notice
must include the following:
(1) A description
of the discharge and cause;
(2) The
duration of the discharge, including exact dates and times, and if not
corrected, the time that the unauthorized discharge is expected to cease, and
what steps are being taken to eliminate, minimize, and prevent recurrence of
the discharge.
5. All ground waters and surface waters of
the State shall at all times, regardless of flow, be free from:
a. Sewage, industrial waste, or other waste
that will settle to form sludge deposits that are unsightly, putrescent, or
odorous to such a degree as to create a nuisance, or interfere with classified
water uses or existing water uses;
b. Floating debris, oil, grease, scum, and
other floating material attributable to sewage, industrial waste, or other
waste in amounts sufficient to be unsightly to such a degree as to create a
nuisance or interfere with classified water uses or existing water
uses;
c. Sewage, industrial, or
other waste which produce taste or odor or change the existing color or
physical, chemical, or biological conditions in the receiving waters or
aquifers to such a degree as to create a nuisance, or interfere with classified
water uses (except classified uses within mixing zones as described in this
regulation) or existing water uses; and d. High temperature, toxic, corrosive,
or deleterious substances attributable to sewage, industrial waste, or other
waste in concentrations or combinations which interfere with classified water
uses (except classified uses within mixing zones as described in this
regulation), existing water uses, or which are harmful to human, animal, plant
or aquatic life.
6.
Waters where classified uses are not being attained can be reclassified for
protection of an attainable use and standards designated for that use where:
a. Natural conditions prevent the attainment
of the use; or
b. Natural,
ephemeral, intermittent, low flow conditions, or water levels prevent the
attainment of the use; or
c. Human
caused conditions or sources prevent the attainment of the use and cannot be
remedied or would cause more environmental damage to correct than to leave in
place; or
d. Dams, diversions, or
other types of hydrologic modifications preclude the attainment of the use, and
it is not feasible to restore the waterbody to its original condition or to
operate such modification in a way that would result in the attainment of the
use; or
e. Physical conditions
related to the natural features of the water body, such as the lack of a proper
substrate, cover, flow, depth, pools, riffles, and the like, preclude
attainment of aquatic life protection uses; or
f. Controls more stringent than those
required by Sections
301(b) and 306 of the
Clean Water Act would result in substantial and widespread economic and social
impact.
7. Before the
Department may grant a variance for any water of the State, there must be a
demonstration that one of the following factors for reclassifying uses has been
satisfied:
a. Natural conditions prevent the
attainment of the use; or
b.
Natural, ephemeral, intermittent, low flow conditions, or water levels prevent
the attainment of the use; or
c.
Human caused conditions or sources prevent the attainment of the use and cannot
be remedied or would cause more environmental damage to correct than to leave
in place; or
d. Dams, diversions,
or other types of hydrologic modifications preclude the attainment of the use,
and it is not feasible to restore the waterbody to its original condition or to
operate such modification in a way that would result in the attainment of the
use; or
e. Physical conditions
related to the natural features of the water body, such as the lack of a proper
substrate, cover, flow, depth, pools, riffles, and the like, preclude
attainment of aquatic life protection uses; or
f. Controls more stringent than those
required by Sections
301(b) and 306 of the
Clean Water Act would result in adverse social and economic impact,
disproportionate to the benefits to the public health, safety, or welfare as a
result of maintaining the standard.
8. If the demonstration necessary under
Section E.7 above has been satisfied, the Department may then grant a variance
provided the following apply:
a. The variance
is granted to an individual discharger for a specific pollutant(s) or
parameter(s) and does not otherwise modify water quality standards; and
b. The variance identifies and
justifies the criterion that shall apply during the existence of the variance;
and
c. The variance is established
as close to the underlying criterion as is possible and, upon expiration of the
variance, the underlying criterion shall become the effective water quality
standard for the waterbody; and
d.
The variance is reviewed every three (3) years, at a minimum, and extended only
where the conditions for granting the variance still apply; and
e. The variance does not exempt the
discharger from compliance with any applicable technology or other water
quality-based permit effluent limitations; and
f. The variance does not affect permit
effluent limitations for other dischargers.
9. Prior to removing any uses or granting a
variance, notice and an opportunity for a public hearing shall be
provided.
10. Discharge of fill
into waters of the State is not allowed unless the activity is consistent with
Department regulations and will result in enhancement of classified uses with
no significant degradation to the aquatic ecosystem or water quality.
11. In order to protect and maintain lakes
and other waters of the State, consideration needs to be given to the control
of nutrients reaching the waters of the State. Therefore, the Department shall
control nutrients as prescribed below.
a.
Discharges of nutrients from all sources, including point and nonpoint, to
waters of the State shall be prohibited or limited if the discharge would
result in, or if the waters experience growths of, microscopic or macroscopic
vegetation such that the water quality standards would be violated or the
existing or classified uses of the waters would be impaired. Loading of
nutrients shall be addressed on an individual basis as necessary to ensure
compliance with the narrative and numeric criteria.
b. Numeric nutrient criteria for lakes are
based on an ecoregional approach which takes into account the geographic
location of the lakes within the State and are listed below. These numeric
criteria are applicable to lakes of forty (40) acres or more. Lakes of less
than forty (40) acres will continue to be protected by the narrative criteria.
(1) For the Blue Ridge Mountains ecoregion of
the State, total phosphorus shall not exceed 0.02 mg/L, chlorophyll a
shall not exceed 10 µg/L, and total nitrogen shall not exceed
0.35 mg/L.
(2) For the Piedmont and
Southeastern Plains ecoregions of the State, total phosphorus shall not exceed
0.06 mg/L, chlorophyll a shall not exceed 40 µg/L, and
total nitrogen shall not exceed 1.50 mg/L.
(3) For the Middle Atlantic Coastal Plains
ecoregion of the State, total phosphorus shall not exceed 0.09 mg/L,
chlorophyll a shall not exceed 40 µg/L, and total
nitrogen shall not exceed 1.50 mg/L.
c. In evaluating the effects of nutrients
upon the quality of lakes and other waters of the State, the Department may
consider, but not be limited to, such factors as the hydrology and morphometry
of the waterbody, the existing and projected trophic state, characteristics of
the loadings, and other control mechanisms in order to protect the existing and
classified uses of the waters.
d.
The Department shall take appropriate action, to include, but not be limited
to: establishing numeric effluent limitations in permits, establishing Total
Maximum Daily Loads, establishing waste load allocations, and establishing load
allocations for nutrients to ensure that the lakes attain and maintain the
above narrative and numeric criteria and other applicable water quality
standards.
e. The criteria specific
to lakes shall be applicable to all portions of the lake. For this purpose, the
Department shall define the applicable area to be that area covered when
measured at full pool elevation.
12.
a.
The water temperature of all Freshwaters which are free flowing
shall not be increased more than 5°F (2.8°C) above natural temperature
conditions and shall not exceed a maximum of 90°F (32.2°C) as a result
of the discharge of heated liquids unless a different site-specific temperature
standard as provided for in C.12. has been established, a mixing zone as
provided in C.10. has been established, or a Section
316(a) determination
under the Federal Clean Water Act has been completed.
b. The weekly average water temperature of
all Shellfish Harvesting, Class SA and Class SB waters shall not exceed 4°F
(2.2°C) above natural conditions during the fall, winter or spring, and
shall not exceed 1.5°F (0.8°C) above natural conditions during the
summer as a result of the discharge of heated liquids unless a different
site-specific temperature standard as provided for in C.12. has been
established, a mixing zone as provided for in C.10 has been established, or a
Section 316(a) determination
under the Federal Clean Water Act has been completed.
c. The weekly average water temperature of
all Freshwaters which are lakes shall not be increased more than 5°F
(2.8°C) above natural conditions and shall not exceed 90°F (32.2°C)
as a result of the discharge of heated liquids unless a different site-specific
temperature standard as provided for in C.12. has been established, a mixing
zone as provided in C.10. has been established, or a Section
316(a) determination
under the Federal Clean Water Act has been completed.
13. Numeric criteria based on organoleptic
data (prevention of undesirable taste and odor) are adopted herein. Those
substances and their criteria are listed in the appendix. For those substances
which have aquatic life and/or human health numeric criteria and organoleptic
numeric criteria, the most stringent of the three (3) shall be used for
derivation of permit effluent limitations.
14. Numeric criteria for the protection and
maintenance of all classes of surface waters are adopted herein and are listed
in Sections E, G, and the appendix. Footnotes that further describe the
application of these numeric criteria are included in the appendix.
a. Application of numeric criteria to protect
aquatic life.
(1) The stated CMC value shall
be used as an acute toxicity number for calculating permit effluent
limitations.
(2) The stated CCC
value shall be used as a chronic toxicity number for calculating permit
effluent limitations.
(3) If metals
concentrations for numeric criteria are hardness-dependent, the CMC and CCC
concentrations shall be based on 25 mg/L hardness (as expressed as
CaCO3) if the ambient hardness is less than 25 mg/L.
Concentrations of hardness less than 400 mg/L maybe based on the actual mixed
stream hardness if it is greater than 25 mg/L and less than 400 mg/L and 400
mg/L if the ambient hardness is greater than 400 mg/L.
(4) If separate numeric criteria are given
for fresh and salt waters, they shall be applied as appropriate. In
transitional tidal and estuarine areas, the Department shall apply the more
stringent of the criteria to protect the existing and classified uses of the
waters of the State.
(5) The
Department shall review new or revised EPA criteria for adoption by South
Carolina when published in final form.
(6) If the State develops site-specific
criteria for any substances for which EPA has developed national criteria, the
site-specific criteria shall supersede the national criteria.
b. Application of numeric criteria
to protect human health.
(1) If separate
numeric criteria are given for organism consumption, water and organism
consumption (W/O), and drinking water Maximum Contaminant Levels (MCLs), they
shall be applied as appropriate. The most stringent of the criteria shall be
applied to protect the existing and classified uses of the waters of the
State.
(2) The Department shall
review new or revised EPA criteria for adoption by South Carolina when
published in final form by EPA.
(3)
If the State develops site-specific criteria for any substances for which EPA
has developed national criteria, the site-specific criteria shall supersede the
national criteria.
(4) Adoption of
EPA human health criteria does not preclude the Department from considering
health effects of other pollutants or from considering new or revised EPA
criteria when developing effluent permit conditions.
c. Application of criteria for the derivation
of permit effluent limitations.
(1) Numeric
criteria for substances listed in Sections E, G, and the appendix shall be used
by the Department to derive NPDES permit effluent limitations at the applicable
critical flow conditions as determined by the Department unless an exception is
provided below.
(2) When the
derived permit effluent limitation based on aquatic life numeric criteria is
below the practical quantitation limit for a substance, the derived permit
effluent limitation shall include an accompanying statement in the permit that
the practical quantitation limit using approved analytical methods shall be
considered as being in compliance with the limit. Appropriate biological
monitoring requirements shall be incorporated into the permit to determine
compliance with appropriate water quality standards. Additionally, if naturally
occurring instream concentration for a substance is higher than the derived
permit effluent limitation, the Department may establish permit effluent
limitations at a level higher than the derived limit, but no higher than the
natural background concentration. In such cases, the Department may require
biological instream monitoring and/or WET testing.
(3) When the derived permit effluent
limitation based on human health numeric criteria is below the practical
quantitation limit for a substance, the derived permit effluent limitation
shall include an accompanying statement in the permit that the practical
quantitation limit using approved analytical methods shall be considered as
being in compliance with the limit. Additionally, if naturally occurring
instream concentration for a substance is higher than the derived permit
effluent limitation, the Department may establish permit effluent limitations
at a level higher than the derived limit, but no higher than the natural
background concentration.
(4) NPDES
permit effluent limitations for metals shall normally be expressed on the
permits as total recoverable metals, but the Department may utilize a
federally-approved methodology to predict the dissolved fraction, partitioning
coefficient, or the bioavailable portion of metals in calculating these
limits.
(5) Except as provided
herein, where application of MCLs or W/O numeric criteria using annual average
flow for carcinogens, 7Q10 (or 30Q5 if provided by the applicant) for
noncarcinogens, or comparable tidal conditions as determined by the Department
results in permit effluent limitations more stringent than limitations derived
from other applicable human health criteria (organism consumption only),
aquatic life criteria, or organoleptic numeric values, MCLs or W/O shall be
used in establishing permit effluent limitations for human health protection.
The Department may, after Notice of Intent included in a notice of a proposed
NPDES permit in accordance with R.61-9.124.10,
Procedures for Decision Making, determine that drinking water MCLs or W/O shall
not apply to discharges to those waterbodies where there is: no potential to
affect an existing or proposed drinking water source and no state-approved
source water protection area. For purposes of this section, a proposed drinking
water source is one for which a complete permit application, including plans
and specifications for the intake, is on file with the Department at the time
of consideration of an NPDES permit application for a discharge that will
affect or has the potential to affect the drinking water source.
(6) Except as provided herein, the Department
may determine that an NPDES permitted discharge will not cause, have reasonable
potential to cause, or contribute to an exceedance of the numeric criterion for
turbidity under the following conditions:
i.
The facility withdraws its surface intake water containing turbidity from the
same body of water into which the discharge is made;
ii. The facility does not significantly
concentrate or contribute additional turbidity to the discharged water; or iii.
The facility does not alter the turbidity through chemical or physical means
that would cause adverse water quality impacts to occur.
(7) Site-specific permit effluent limitations
and alternate criteria less stringent than those derived in accordance with the
above requirements may be derived where it is demonstrated that such limits and
criteria shall maintain the existing and classified uses, adequate opportunity
for public participation in such derivation process has occurred, and the
effluent shall not cause human health criteria to be exceeded. Where a
site-specific permit effluent limitation and alternate criterion has been
derived, such derivation shall be subject to EPA review as appropriate. Also,
at a minimum, opportunity for input in derivation of a site-specific permit
effluent limitation and alternate criterion shall be provided via public notice
in NPDES permit notices.
(8) In
order to protect recreational uses in freshwaters (including FW, and all types
of Trout Waters) of the State, NPDES permit effluent limitations shall be
specified as indicated below:
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i. Monthly Average (E. coli)
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126 MPN per 100 mL
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ii. Daily Maximum (E. coli)
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349 MPN per 100 mL (see c(12) below)
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iii. Shellfish protection
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Class SFH requirements for fecal coliform (see
c(11)i. and c(11)ii. below) may be specified (in addition to the limits above)
for the protection of downstream waters (regardless of their individual
classification) with shellfish uses.
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iv. Municipal separate storm sewer systems
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For municipal separate storm sewer systems (as
described in R.61-9.122.26.a.),
compliance with the bacterial standards shall be determined in accordance with
c(13) below.
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v. Protection of upstream and/or downstream
waters
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Permit limitations may include (in addition to the
requirements listed in c(8)i. and c(8)ii. above) one or more bacterial
limitations for fecal coliform, E. coli, and/or enterococci to
protect both uses in the specific receiving waterbody and also to protect any
upstream and/or downstream uses that may be required. If more than one
bacterial limit is required, the conditions associated with each section below
shall apply independently regardless of the water classification at the point
of discharge.
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vi. Class ORW or ONRW protection
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For Class ORW or ONRW waters, the bacterial
requirements shall be those applicable to the classification of the waterbody
immediately prior to reclassification to either ORW or ONRW, including
consideration of natural conditions. See G.5 and G.7 for prohibitions.
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(9) In
order to protect recreational uses in Class SA saltwaters of the State, NPDES
permit effluent limitations shall be specified as indicated below:
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i. Monthly Average (enterococci)
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35 MPN per 100 mL
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ii. Daily Maximum (enterococci)
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104 MPN per 100 mL (see c(12) below)
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iii. Shellfish protection
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Class SFH requirements for fecal coliform (see
c(11)i. and c(11)ii. below) may be specified (in addition to the limits above)
for the protection of upstream and/or downstream waters (regardless of their
individual classification) with shellfish uses.
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iv. Municipal separate storm sewer systems
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For municipal separate storm sewer systems (as
described in R.61-9.122.26.a.),
compliance with the bacterial standards shall be determined in accordance with
c(13) below.
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v. Protection of upstream downstream waters
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and/or Permit limitations may include (in addition to
the requirements listed in c(9)i. and c(9)ii. above) one or more bacterial
limitations for fecal coliform, E. coli, and /or enterococci to protect both
uses in the specific receiving waterbody and also to protect any upstream or
downstream uses that may be required. If more than one bacterial limit is
required, the conditions associated with each section above
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or below shall apply independently regardless of the
water classification at the point of discharge.
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vi. Class ORW or ONRW protection
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For Class ORW or ONRW waters, the bacterial
requirements shall be those applicable to the classification of the waterbody
immediately prior to reclassification to either ORW or ONRW, including
consideration of natural conditions. See G.5 and G.7 for prohibitions.
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(10)
In order to protect recreational uses in Class SB saltwaters of the State,
NPDES permit effluent limitations shall be specified as indicated below:
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i. Monthly Average (enterococci)
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35MPNper lOOmL
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ii. Daily Maximum (enterococci)
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104 MPN per 100 mL (see c(12) below)
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iii. Class SA recreational daily maximum and/or
shellfish protection
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Class SA daily maximum (see c(9)ii. above)
recreational use requirements for enterococci and/or Class SFH requirements
(see c(ll)i. and c(ll)ii. below) for fecal coliform may be specified (in
addition to the limits above) for the protection of upstream and/or downstream
waters (regardless of their individual classification).
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iv. Municipal separate storm sewer systems
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For municipal separate storm sewer systems (as
described in R.61-9.122.26.a.),
compliance with the bacterial standards shall be determined in accordance with
c(13) below.
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V. Protection of upstream and/or downstream
waters
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Permit limitations may include (in addition to the
requirements hsted in c(10)i. and c(10)ii. above) one or more bacterial
limitations for fecal coliform, E. coli and /or enterococci to protect both
uses in the specific receiving waterbody and also to protect any upstream or
downstream uses that may be required. If more than one bacterial limit is
required, the conditions associated with each section above or below shall
apply independently regardless of the water classification at the point of
discharge.
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vi. Class ORW or ONRW protection
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For Class ORW or ONRW waters, the bacterial
requirements shall be those applicable to the classification of the waterbody
immediately prior to reclassification to either ORW or ONRW, including
consideration of natural conditions. See G.5 and G.7 for prohibitions.
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(11)
In order to protect for the consumption of shellfish, for any discharge either
directly or indirectly in Class SFH waters or in Class SA, Class SB, ORW, or
ONRW waters with existing and/or approved shellfish harvesting uses as
described in Section C.7, including protection of shellfish upstream and/or
downstream uses in all waters regardless of their classification, NPDES permit
effluent limitations shall be specified as indicated below:
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i. For protection of shellfish uses-Monthly Average
(Fecal coliform)
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14 MPN per 100 mL
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ii. For protection of shellfish uses- Daily Maximum
(Fecal coliform)
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43 MPN per 100 mL (see c(12) below)
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iii. For protection of recreational uses - Monthly
Average (enterococci)
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35 MPN per 100 mL
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iv. For protection of recreational uses-Daily Maximum
(enterococci)
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104 MPN per 100 mL (see c(12) below)
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v. Protection of upstream and/or downstream
waters
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Permit limitations may include (in addition to the
requirements listed in c(11)i. through c(11)iv. above) one or more bacterial
limitations for fecal coliform, E. coli and /or enterococci to protect both
uses in the specific receiving waterbody and also to protect any upstream or
downstream uses that may be required. If more than one bacterial limit is
required, the conditions associated with each section above shall apply
independently regardless of the water classification at the point of
discharge.
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vi. Municipal separate storm sewer systems
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For municipal separate storm sewer systems (as
described in R.61-9.122.26.a.),
compliance with the bacterial standards shall be determined in accordance with
c(13) below.
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(12)
Provided the permittee verifies in writing to the Department that conditions
(12)i. through (12)iv. below have been met, the permittee would be in
compliance with the daily maximum bacterial requirement. However, nothing in
this regulation precludes the Department from taking action, depending on the
individual circumstances, to protect public health and/or the environment.
i. If the facility exceeds the permitted
Daily Maximum bacterial limitation listed above (for E. coli, enterococci, or
fecal coliform) but two (2) additional samples collected within forty-eight
(48) hours of the original sample result do NOT exceed the required Daily
Maximum limit; and
(A) For all waters not
involving shellfish protection (regardless of the specific water
classification), the individual bacterial sample result has not exceeded 800
MPN per 100 mL, and for those waters involving shellfish protection, the
individual bacterial sample result for fecal coliform has not exceeded 200 MPN
per 100 mL; and
(B) There is
neither an existing Consent Order nor Administrative Order associated with the
facilities operation of their disinfection system; and
(C) Either:
1. For facilities that routinely collect ten
(10) bacterial samples per month (or one hundred twenty (120) or more samples
per calendar year), there were no more than four (4) total bacteria samples
exceeding the daily maximum limit in the previous twelve (12) months;
or
2. For facilities other than
those listed in (C)1. above (e.g., smaller facilities or those that do not
routinely collect ten (10) samples or more per month), there was no more than
one (1) bacterial sample exceeding the daily maximum limit in the previous
twelve (12) months; and ii. The permittee verifies that all disinfection
equipment was fully functional, and the solids handling system was fully
functional during that monitoring period; and iii. Any additional bacterial
sampling collected during the monthly monitoring period when the daily maximum
exceedance occurred was reasonably distributed in time while maintaining
representative sampling; and iv. The permittee must provide sufficient
laboratory data sensitivity (e.g., dilutions) to accurately represent the
effluent bacterial concentration to utilize this procedure. Effluent bacterial
results reported as greater than (>) do not meet this criteria, since the
actual results are unknown.
(13) For waters of the State, where a permit
has been issued pursuant to R.61-9.122.26 and
R.61-9.122.34, the Department shall
consider the permittee in compliance with the established bacterial (i.e., E.
coli, enterococci, fecal coliform) criteria for recreational uses of the
waterbody if the permittee is in compliance with their permit.
(14) TMDL(s), WLA(s), and LA(s) included in
currently approved freshwater fecal coliform TMDL documents shall be converted
to E. coli utilizing a translator equation established by the
Department and shall be based upon existing targets included in approved
freshwater fecal coliform bacteria TMDL documents.
(15) All effluent permit limitations which
include WET shall require that the WET tests be conducted using
Ceriodaphnia dubia (C. dubia), except as
stated. If the salinity of a discharge to a saline waterbody is high enough to
be toxic to C. dubia, Mysidopsis bahia
(M. bahia) shall be used. If the hardness of a waterbody is
low enough to be toxic to C. dubia, then Daphnia
ambigua (D. ambigua) may be used. Low salinity
discharges to saltwater may be tested using either C. dubia or
M. bahia with salinity adjustment, as determined by the
Department. The Department may consider an alternative species if it can be
demonstrated that the proposed species meets the requirements of
40 CFR
136.4 and
5, as approved by EPA. EPA test
methods (40 CFR
136) for acute and chronic toxicity testing
with freshwater organisms or marine and estuarine organisms must be followed.
The Department may consider an alternative method if it can be demonstrated
that the proposed method meets the requirements of
40 CFR
136 and is approved by
EPA.
d. Evaluation of
ambient water quality.
(1) If the numeric
criterion for toxic pollutants is lower than the analytical detection limit,
the criterion is not considered violated if the ambient concentration is below
the detection limit and the instream indigenous biological community is not
adversely impacted.
(2) If the
ambient concentration is higher than the numeric criterion for toxic
pollutants, the criterion is not considered violated if biological monitoring
has demonstrated that the instream indigenous biological community is not
adversely impacted.
(3) In order to
appropriately evaluate the ambient water quality for the bioavailability of the
dissolved portion of hardness dependent metals, the Department may utilize a
federally-approved methodology to predict the dissolved fraction or
partitioning coefficient in determining compliance with water quality standards
established in this regulation.
(4)
The assessment of fecal coliform for purposes of evaluating the shellfish
harvesting use for South Carolina's Shellfish Management Units is conducted in
accordance with provisions of R.61-47, Shellfish.
R.61-47 also includes specific
language describing the use of the allowable ten percent (10%) exceedance value
in the shellfish program.
(5) The
assessment of enterococci for purposes of issuing swimming advisories for ocean
beaches for recreational use will be based on the single sample maximum of
104/100 mL.
(6) The assessment of
enterococci and E. coli for purposes of Section
303(d) listing
determinations for recreational uses shall be based on either the geometric
mean with an allowable ten percent (10%) exceedance,where sufficient data
exists to calculate a geometric mean, or the single sample maximum with an
allowable ten percent (10%) exceedance.
(7) The assessment of total microcystins for
purposes of issuing a swimming advisory for freshwater recreational use will be
based on the single sample maximum of 8 µg/L. Once issued, the swimming
advisory will remain in effect until resample results indicate the toxin
concentration falls below 8 µg/L.
(8) The assessment of total microcystins for
purposes of Section
303(d) listing
determinations for recreational uses shall be based on no more than three (3)
swimming advisories in a three (3)-year assessment period.
(9) The assessment of cylindrospermopsin for
purposes of issuing a swimming advisory for freshwater recreational use will be
based on the single sample maximum of 15 µg/L. Once issued, the swimming
advisory will remain in effect until resample results indicate the toxin
concentration falls below 15 µg/L.
(10) The assessment of cylindrospermopsin for
purposes of Section
303(d) listing
determinations for recreational uses shall be based on no more than three (3)
swimming advisories in a three (3)-year assessment period.
15. The Department may require
biological or other monitoring in NPDES permits to further ascertain any
bioaccumulative effects of pollutants. Such monitoring may include analyses of
fish and shellfish, macroinvertebrates, macrophytes, and/or sediments in order
to assess the accumulation of pollutants in tissues or sediments that:
a. May cause or have the potential to cause
adverse impacts to the balanced indigenous aquatic community; and
b. May cause or have the potential to cause
adverse impacts to human health and/or terrestrial flora and fauna.
16. The Department may consider
other scientifically-defensible published data which are appropriate for use in
developing permit limits and evaluating water quality for constituents for
which EPA has not developed national criteria or South Carolina has no
standards.
a. The Department shall apply a
sensitivity factor to aquatic toxicity data unless, in the Department's
judgment, the data represent a minimum of three (3) appropriately sensitive
species representing three (3) taxonomic groups (plant, macroinvertebrate, and
fish).
(1) If only an acute toxicity effect
concentration for a number of species for a particular pollutant is given as an
LC50, the lowest concentration should be divided by an
acute-to-chronic ratio (ACR) of ten (10) and a sensitivity factor of 3.3, for
an acceptable instream concentration in order to protect against chronic
toxicity effects.
(2) If a chronic
toxicity effect concentration for a number of species for a particular
pollutant is given as a no observed effect concentration (NOEC), the lowest
concentration should be divided by a sensitivity factor of 3.3 in order to
protect against chronic toxicity to the most sensitive species.
b. The Department must notify the
permittee that other such data were used in developing permit limits and
provide justification for their use.
17. Tests or analytical methods to determine
compliance or non-compliance with standards shall be made in accordance with
methods and procedures approved by the Department and the EPA. In making any
tests or applying analytical methods to determine compliance or non-compliance
with water quality standards,representative samples shall be collected in
accordance with methods and procedures approved by the Department and the EPA.
Consideration of representative sample methods shall include the following:
a. Surface water and ground water samples
shall be collected so as to permit a realistic appraisal of quality and actual
or potential damage to existing or classified water uses. For ground waters,
consideration shall be given to, but shall not be limited to, depth to water
table, flow direction, and velocity. For surface waters, time of day, flow,
surface area, and depth shall be considered.
b. Biological assessment methods may be
employed in appropriate situations to determine abnormal nutrient enrichment,
trophic condition, LC50, concentration of toxic
substances, acceptable instream concentrations, or acceptable effluent
concentrations for maintenance of a balanced indigenous aquatic
community.
c. Temporal distribution
of samples in tidally influenced waters shall cover the full range of tidal
conditions.
d. Ambient toxicity
tests used for screening purposes shall be conducted using Ceriodaphnia
dubia (C. dubia), except as stated. If salinity of a waterbody is high
enough to be toxic to C. dubia, Mysidopsis bahia (M. bahia)
will be used. If the hardness of a waterbody is low enough to be toxic to
C. dubia, then Daphnia ambigua (D. ambigua)
may be used. The Department may consider an alternative species if it can be
demonstrated that the proposed species meets the requirements of 40 CFR Part
136 .4 and 5 , as approved by EPA. EPA test methods (40 CFR Part 136) for acute
and chronic toxicity testing with freshwater organisms or marine and estuarine
organisms must be followed. The Department may consider an alternative method
if it can be demonstrated that the proposed method meets the requirements of 40
CFR Part 136, and is approved by EPA.
18. For the protection of human health,
methylmercury concentration in fish or shellfish shall not exceed 0.3 mg/kg in
wet weight of edible tissue.
a. NPDES permit
implementation for methylmercury will require mercury monitoring, assessment
and minimization for discharges that meet the following conditions;
(1) The receiving stream is impaired for
methylmercury in fish or shellfish tissue; and
(2) The discharge or proposed discharge has
consistently quantifiable levels of mercury.
b. The need for a total mercury effluent
limit, for the protection of aquatic life and/or human health, pursuant to
R.61-9.122.44(d),
shall be based on a reasonable potential analysis of the discharge compared to
the mercury standards for ambient waters.
19. The assessment of methylmercury in fish
or shellfish for purposes of Section
303(d) listing
determinations shall be based on the Department's Fish Consumption
Advisories.
