Mississippi Administrative Code › Title 11 - Mississippi Department of Environmental Quality › Part 6 - Wastewater Pollution Control Regulations › Chapter 2 - Mississippi Commission on Environmental Quality Regulations for Water Quality Criteria For Intrastate, Interstate, And Coastal Waters › Rule 11-6-2.1 - General Conditions Applicable to All Surface Waters of the State

Current through June 25, 2024
A.
Antidegradation
:
				The policy inherent in the standards shall be to protect water quality existing
				at the time these water quality standards were adopted and to upgrade or
				enhance water quality within the State of Mississippi. Waters whose existing
				quality is better than the established standards will be maintained at high
				quality unless the Commission finds, after full satisfaction of the
				intergovernmental coordination and public participation provisions of the
				State's continuing planning process, that allowing lower water quality is
				necessary to accommodate important economic or social development in the area
				in which the waters are located.
In no event, however, may degradation of water quality
				  interfere with, or become injurious to, existing in-stream water uses. Further,
				  in no case will water quality be degraded below (or above) the base levels set
				  forth in these standards for the protection of the beneficial uses described
				  herein. In addition, the State will assure that there shall be achieved the
				  highest statutory and regulatory requirements for all new and existing point
				  sources and all cost-effective and reasonable best management practices for
				  nonpoint source control.
Where the Commission determines that high quality waters
				  constitute an outstanding national resource, such as waters of National State
				  Parks, Wildlife Refuges, and waters of exceptional recreational or ecological
				  significance, that water quality shall be maintained and protected. For the
				  purposes of this rule, existing uses are defined as those uses actually
				  attained in the waterbody on or after November 28, 1975, whether or not they
				  are included in the Water Quality Criteria.
B.
Sampling and
				Assessment
: The limiting values of water quality herein described
				shall be measured by the Commission in surface waters under consideration as
				determined by good environmental engineering and scientific practice and after
				consultation with affected parties. Samples shall be taken from points so
				distributed over the seasons of the year, time of day, and area and depth of
				the waters being studied to provide a realistic assessment of water quality.
				All sampling must be conducted in accordance with the appropriate MDEQ-approved
				Quality Management Plan (QMP), Quality Assurance Project Plan (QAPP), or its
				equivalent.
Water quality assessments are technical reviews of physical,
				  chemical, bacteriological, biological, and/or toxicological data and
				  information to determine the quality of the State's surface water resources.
				  Monitoring data are evaluated against both narrative and numeric water quality
				  criteria to determine if a waterbody is supporting or not supporting its
				  classification(s)/designated use(s). Water quality assessments regarding
				  designated use attainment are conducted in accordance with the most recent
				  version of
Mississippi's Consolidated Listing and Assessment
				  Methodology
(CALM). All samples shall be collected and analyzed in
				  accordance with the appropriate methodology specified in 40 CFR 136 and with
				  the latest edition of
Standard Methods for the Examination of Water and
				  Wastewater
or other methods acceptable to the Commission.
C. Waterbody Classifications,
Designated Uses, and Attainment
: Water quality
				standards define the water quality goals of each waterbody or portion thereof,
				in part, by designating the use or uses to be made of the water. States adopt
				water quality standards to protect public health or welfare, to enhance water
				quality, and to serve the purposes of the Clean Water Act: (1) provide,
				wherever attainable, water quality for the protection and propagation of fish,
				shellfish, and wildlife, as well as, recreation in and on the water and (2)
				consider the use and value of State waters for public water supplies,
				protection and propagation of fish, shellfish and wildlife, recreation in and
				on the water, agriculture and industrial purposes, and navigation.
The State of Mississippi assigns one or more waterbody
				  classifications to all Surface Waters of the State. Each waterbody
				  classification has one or more corresponding designated uses. A waterbody, or a
				  specific waterbody segment, may be assigned multiple waterbody classifications.
				  When multiple classifications are assigned to a waterbody, the State must
				  ensure protection of the most sensitive use. The State must also consider the
				  water quality standards of downstream waters and ensure that its water quality
				  standards provide for the attainment and maintenance of the water quality
				  standards of downstream waters. In no case shall it be permissible to deposit
				  or introduce materials into Surface Waters of the State that will cause
				  impairment of the designated use(s) of said waters.
Certain Surface Waters of the State may not fall within
				  desired or prescribed limitations as outlined within these water quality
				  standards. In such instances, the Commission may authorize exceptions or
				  alternatives to these criteria as described in more detail within Rule 2.5
				  Implementation of Water Quality Standards.
D.
Natural
				Conditions:
Natural conditions are defined as background water
				quality conditions due only to non-anthropogenic sources. The criteria herein
				apply specifically with regard to substances attributed to sources (permitted
				discharges, nonpoint sources, or in-stream activities) as opposed to natural
				phenomena. Some water bodies may have characteristics that are naturally
				outside the criteria established herein. Therefore, naturally occurring
				conditions that preclude attainment of these criteria should not be interpreted
				as violations of the criteria.
E.
Site-Specific Modified Criteria:
In some instances,
				the statewide aquatic life criteria for one or more parameters may not be
				appropriate for a particular waterbody or waterbody segment. In such
				circumstances, the Commission may establish site-specific modified aquatic life
				criteria for one or more parameters applicable to a specific waterbody or
				waterbody segment. Site-specific modified aquatic life criteria must be based
				on natural conditions, the recalculation procedure outlined in
Revised
				Deletion Process for the Site Specific Recalculation Procedure for Aquatic Life
				Criteria - 2013 (U.S. EPA-823-R-13-001)
, or other scientifically
				defensible methods.
Site-specific modified aquatic life criteria must be based on
				  sound scientific rationale and supported by adequate scientific evidence to
				  validate that the modified criteria are more appropriate for the identified
				  waterbody or waterbody segment. All site-specific modified aquatic life
				  criteria must fully maintain and protect the designated use(s) within the
				  identified waterbody or waterbody segment. All site-specific modified aquatic
				  life criteria must also protect the attainment of water quality standards
				  within downstream waters. Site-specific modified aquatic life criteria are
				  subject to Mississippi public participation requirements for revisions to water
				  quality standards and will be subject to review by the U.S. EPA.
F.
Criteria for New
				Materials
: Industries continue to produce new materials whose
				characteristics and effects are unknown at this time or for which national
				water quality criteria recommendations have not been established. For the
				purposes of setting water quality standards or permit limits on a case-by-case
				basis, these new materials shall be evaluated on their merits as information
				becomes available to the Commission. Sources of information shall include, but
				not be limited to, the latest edition of
Quality Criteria for
				Water
, prepared by the U.S. Environmental Protection Agency (U.S. EPA)
				pursuant to Section 304(a) of the Clean Water Act and Title XIV of the Federal
				Public Health Services Act: Safety of Public Water Systems (Safe Drinking Water
				Act).
G. Water Contact Advisories:
Bacteria: According to
				  40
				  CFR 131.41(b), Coastal
				  Recreational Waters are defined as marine coastal waters (including coastal
				  estuaries) that are suitable for recreational purposes, including but not
				  limited to, such water contact activities as swimming, wading, and water
				  skiing. Coastal recreational waters do not include inland waters or waters
				  upstream from the mouth of a river or a stream having a natural connection to
				  the open sea. Water quality monitoring for bacteria is conducted by MDEQ within
				  Coastal Recreational Waters to protect the health of bathers. Water contact is
				  discouraged on Mississippi's public access bathing beaches along the shoreline
				  of Jackson, Harrison, and Hancock Counties when enterococci exceed 104 colonies
				  per 100 ml. When enterococci counts exceed 104 per 100 ml at the public access
				  beaches, water contact advisories are issued by Mississippi's Beach Monitoring
				  Task Force.
H.
Definitions:
(1)
Acute criterion or Criteria Maximum Concentration
				(CMC)
is the highest concentration of a pollutant to which aquatic
				life can be exposed for a short period of time (1-hour average) without
				deleterious effects. (
				40
				CFR 131.36 )
(2)
Best management practice
				(BMP)
means a structural or non-structural management-based
				practice used singularly or in combination to reduce nonpoint source inputs to
				receiving waters in order to achieve water quality protection goals.
(3)
Bioconcentration factor
				(BCF)
is defined as the ratio (in L/kg-tissue) of the
				concentration of a substance in tissue of an aquatic organism to its
				concentration in the ambient water, in situations where the organism is exposed
				through the water only and the ratio does not change substantially over time.
				(U.S. EPA-822-B-00-004)
(4)
Biological integrity
is defined as the ability of a
				system to support and maintain a balanced, integrated, and adaptive community
				of organisms having a composition, diversity, and functional organization
				comparable to that of natural habitats of the region.
(5)
Cancer Potency Factor
				(CPF)
is a measure of the cancer-causing potency of a substance
				estimated by the upper 95 percent confidence limit of the slope of a straight
				line calculated by the Linearized Multistage Model according to the U.S. EPA
				Guidelines (FR 51(185): 339992-34003, and FR 45(231 Part V);
				7931879379).
(6)
Chronic criterion or Criteria Continuous Concentration
				(CCC)
is the highest concentration of a pollutant to which aquatic
				life can be exposed for an extended period of time (4 days) without deleterious
				effects. (
				40
				CFR 131.36 )
(7)
Clean techniques
refers to an integrated system of sample collection and laboratory analytical
				procedures designed to detect concentrations of trace metals below criteria
				levels and eliminate or minimize inadvertent sample contamination that can
				occur during traditional sampling practices.
(8)
Composite
				sampling
is a technique whereby multiple temporally or spatially
				discrete media or tissue samples are combined, thoroughly homogenized, and
				treated as a single sample.
(9)
E. coli (
Escherichia coli
)
is a
				common inhabitant of the intestinal tract of warmblooded animals, and its
				presence in water samples is an indication of fecal pollution and the possible
				presence of enteric pathogens.
(10)
Enteric
				pathogens
are a species of bacteria can be highly pathogenic when
				they enter and colonize the human digestive tract.
(11)
Existing uses are those uses
				actually attained in the waterbody on or after November 28, 1975, whether or
				not they are included in the water quality standards.
(12)
Grab samples
are samples where the entire sample is collected in one uninterrupted
				interval.
(13) Highest attainable
				use is the modified aquatic life, wildlife, or recreation use that is both
				closest to the uses specified in section 101(a)(2) of the Clean Water Act and
				attainable, based on the evaluation of the factor(s) in § 131.10(g) that
				preclude(s) attainment of the use and any other information or analyses that
				were used to evaluate attainability. There is no required highest attainable
				use where the State demonstrates the relevant use specified in section
				101(a)(2) of the Clean Water Act and sub-categories of such a use are not
				attainable.
(14)
Mean
				Annual Flow
is the total of daily mean flows for the full period
				of record divided by the total days for the full period of record.
(15)
Membrane Filtration
				(MF)
is a method of quantitative or qualitative analysis of
				bacterial or particulate matter in a water sample filtered through a membrane
				capable of retaining bacteria.
(16)
				Modified criterion is a waterbody-specific criterion adopted to protect either
				the Modified Fish and Wildlife or Drainage Waters classifications. The
				criterion should be supported by the findings of the respective waterbody's use
				attainability analysis in support of the designated use change and reflect the
				use of scientifically defensible methods. Following adoption of modified
				criteria into Rule
				2.4, the state will submit the modified
				criteria for review and require action by the U.S. EPA before the modified
				criteria supersede the previously applicable criterion.
(17)
Most probable number
				(MPN)
is the most probable number of coliform-group organisms per
				unit volume of sample water.
(18)
Pollutant minimization program in the context of
40 CFR
				131.14, is a structured set of activities to
				improve processes and pollutant controls that will prevent and reduce pollutant
				loadings.
(19)
Point
				source
is a stationary location or fixed facility from which
				pollutants are discharged or emitted. Also, any single identifiable source of
				pollution, e.g., a pipe, ditch, or ship.
(20)
7Q10
is the
				average streamflow rate over seven consecutive days that may be expected to be
				reached as an annual minimum no more frequently than one year in ten
				years.
(21)
7Q2
is the average streamflow rate over seven
				consecutive days that may be expected to be reached as an annual minimum no
				more frequently than one year in two years.
(22)
Stratification
is the formation of layers of water within a waterbody that are of different
				densities. The density difference may be caused by variations of temperature,
				salinity, or concentrations of other dissolved substances within the water at
				different depths.
(23) Surface
				Waters of the State means all waters within the jurisdiction of this state,
				including all streams, lakes, ponds, impounding reservoirs, marshes,
				watercourses, waterways, wells, springs, irrigation systems, drainage systems,
				and all other bodies or accumulations of water, natural or artificial, situated
				wholly or partly within or bordering upon the state, and such coastal waters as
				are within the jurisdiction of the state, except lakes, ponds or other surface
				waters which are wholly landlocked and privately owned, and which are not
				regulated under the Clean Water Act (
				33 U.S.C.
				1251 et seq).
(24)
Threshold odor
				number
is the number of times a sample needs to be diluted with
				clean water in order to reach the level that smell is not detectable.
(25)
Toxic substance
means any substance or combination of substances (including disease-causing
				agents), which after discharge and upon exposure, ingestion, inhalation, or
				assimilation into any organism, whether directly from the environment or
				indirectly by ingestion through food chains, has the potential to cause death,
				disease, behavioral abnormalities, cancer, genetic mutations, physiological
				malfunctions (including malfunctions or suppression in reproduction or growth)
				or physical deformities in such organisms or their offspring.
(26) Use attainability analysis is a
				structured scientific assessment of the factors affecting the attainment of a
				designated use. This assessment may include physical, chemical, biological, and
				economic factors as described in
				40 CFR
				131.10(g).
(27)
Toxic substance
means any substance or combination of substances (including disease-causing
				agents), which after discharge and upon exposure, ingestion, inhalation, or
				assimilation into any organism, whether directly from the environment or
				indirectly by ingestion through food chains, has the potential to cause death,
				disease, behavioral abnormalities, cancer, genetic mutations, physiological
				malfunctions (including malfunctions or suppression in reproduction or growth)
				or physical deformities in such organisms or their offspring.
(28) Waters of the State means all waters
				within the jurisdiction of this state, including all streams, lakes, ponds,
				impounding reservoirs, marshes, watercourses, waterways, wells, springs,
				irrigation systems, drainage systems, and all other bodies or accumulations of
				water, surface and underground, natural or artificial, situated wholly or
				partly within or bordering upon the state, and such coastal waters as are
				within the jurisdiction of the state, except lakes, ponds or other surface
				waters which are wholly landlocked and privately owned, and which are not
				regulated under the Clean Water Act (
				33 U.S.C.
				1251 et seq). Source: Miss. Code Ann. §
										49-17-5(1)(f)
(29) Water quality standards variance is a
				time-limited designated use and criterion for a specific pollutant(s) or water
				quality parameter(s) that reflect the highest attainable condition during the
				term of the water quality standards variance.