Ohio Administrative Code › Title 3745 - Ohio Environmental Protection Agency › Chapter 3745-1 - Water Quality Standards › Section 3745-1-02 - Definitions

Current through all regulations passed and filed
			 through July 1, 2024
[Comment: For dates of non-regulatory government publications,
				publications of recognized organizations and associations, federal rules and
				federal statutory provisions referenced in this rule, see rule
				3745-1-03 of the Administrative
				Code.]
(A) Acronyms and abbreviations
			 used in this chapter are defined as follows:
AAC
Acute aquatic criterion
AAV
Acute aquatic value
ACR
Acute-chronic ratio
ADE
Acceptable daily exposure
AIM
Area of initial mixing
BAF
Bioaccumulation factor
BCC
Bioaccumulative chemical of concern
BCF
Bioconcentration factor
BSAF
Biota-sediment accumulation factor
BW
Body weight
CAC
Chronic aquatic criterion
CAV
Chronic aquatic value
CBOD5
Five-day carbonaceous biochemical oxygen
						  demand
C.F.R.
Code of federal regulations
DOC
Dissolved organic carbon
ECBP
Eastern corn belt plains ecoregion
EC50
Median effective concentration
EOLP
Erie/Ontario lake plain ecoregion
EPA
Environmental protection agency
FACR
Final acute-chronic ratio
FAV
Final acute value
FCM
Food-chain multiplier
FCV
Final chronic value
FPV
Final plant value
GMAV
Genus mean acute value
GMCV
Genus mean chronic value
HCC
Human cancer criterion
HCV
Human cancer value
HELP
Huron/Erie lake plain ecoregion
HNC
Human noncancer criterion
HNV
Human noncancer value
IMZM
Inside mixing zone maximum
IP
Interior plateau ecoregion
IRIS
Integrated risk information system
KOW
Octanol-water partition coefficient
LC50
Median lethal concentration
ln
Natural logarithm
LOAEL
Lowest observed adverse effect level
log10
Base ten logarithm
MDL
Method detection
						  limit
NOAEL
No observed adverse effect level
NPDES
National pollutant discharge elimination
						  system
OMZA
Outside mixing zone average
OMZM
Outside mixing zone maximum
POC
Particulate organic carbon
POTW
Publicly owned treatment works
q1*
Cancer slope factor
QHEI
Qualitative habitat evaluation
						  index
RAD
Risk associated dose
RSC
Relative source contribution
S
Soluble
SACR
Secondary acute-chronic ratio
SAF
Secondary acute factor
SAR
Structure-activity relationship
SAV
Secondary acute value
SMAV
Species mean acute value
SMCV
Species mean chronic value
T
Total
TD
Test dose
temp
Temperature
TL
Trophic level
TMDL
Total maximum daily
						  load
TR
Total recoverable
UF
Uncertainty factor
U.S.C.
United States Code
WAP
Western Allegheny plateau ecoregion
WET
Whole effluent
						  toxicity
WLA
Wasteload
						  allocation
WV
Wildlife value
(B)
			 Technical terms used in this chapter are defined
			 as follows:
(1)
			 "Acceptable daily exposure" or "ADE" means an estimate of the maximum daily
			 dose of a substance which is not expected to result in adverse noncancer
			 effects to the general human population, including sensitive
			 subgroups.
(2) "Act" means the
			 federal Water Pollution Control Act,
			 33 U.S.C. sections
			 1251 to
			 1387.
(3) "Acute aquatic criterion" or "AAC" means
			 the Ohio EPA estimate of the highest  concentration of a
			 material in
			 the water column to which an aquatic
			 community can be exposed briefly without resulting in an unacceptable effect
			 including but not limited to mortality.
(4) "Acute-chronic ratio" or "ACR" means a
			 standard measure of the acute toxicity of a material divided by an appropriate
			 measure of the chronic toxicity of the same material under comparable
			 conditions.
(5) "Acute mixing zone"
			 means the mixture of receiving water and effluent adjacent to a treated or
			 untreated discharge within which the acute aquatic life criteria may be
			 exceeded but the inside mixing zone maximum criteria 
									are not
			 to be exceeded. The acute aquatic life criteria
			 are to
			 be met on the downstream perimeter of the acute mixing zone.
(6) "Acute toxicity" means
			 concurrent and delayed adverse effects that result
			 from an acute exposure and occur within any short observation period which
			 begins when the exposure begins, may extend beyond the
			 exposure period, and usually does not constitute a substantial portion of
			 the life span of the organism.
(7)
			 "Adverse effect" means any deleterious effect to organisms due to exposure to a
			 substance. This includes effects which are or may become debilitating, harmful
			 or toxic to the normal functions of the organism, but does not include
			 nonharmful effects such as tissue discoloration alone or the induction of
			 enzymes involved in the metabolism of the substance.
(8) "Ambient water temperature" means the
			 spatial (longitudinal, lateral and vertical) and temporal water temperature
			 measured in the receiving body of water prior to a specific waste heat
			 discharge, and is outside the influence of any thermal mixing zone.
(9) "Area of initial mixing" or "AIM" means
			 the limited zone where discharge-induced mixing causes the effluent to rapidly
			 mix with the receiving water such that the area 
									is not
			  physically inhabitable to aquatic life.
			 The inside mixing zone maximum criteria may be exceeded within the AIM but
			 is to be
			 met on the perimeter of the AIM.
(10) "Average temperature" represents the
			 arithmetic mean of multiple daily average temperatures over a consecutive
			 fifteen-day or thirty-day period
			 or as otherwise specified in rule.
(11) "Baseline BAF" means:
(a) For organic chemicals, a BAF that is
			 based on the concentration of freely dissolved chemical in the ambient water
			 and takes into account the partitioning of the chemical within the
			 organism.
(b) For inorganic
			 chemicals, a BAF that is based on the wet weight of the
			 tissue.
(12) "Baseline
			 BCF" means:
(a) For organic chemicals, a BCF
			 that is based on the concentration of freely dissolved chemical in the ambient
			 water and takes into account the partitioning of the chemical within the
			 organism.
(b) For inorganic
			 chemicals, a BCF that is based on the wet weight of the
			 tissue.
(13)
									"Beneficial uses" means potential uses of a water body
			 by humans or other organisms, including uses for public water supply,
			 propagation of aquatic life, recreation in and on the water, agricultural,
			 industrial, or other purposes.
(14) "Bioaccumulation"
			 means the net accumulation of a substance by an organism as a result of uptake
			 from all environmental sources.
(15) "Bioaccumulation
			 factor" or "BAF" means the ratio (in 1/kg) of a substance's concentration in
			 the tissue of an aquatic organism to its concentration in the ambient water, in
			 situations where both the organism and its food are exposed and the ratio does
			 not change substantially over time.
(16) "Bioaccumulative
			 chemical of concern" or "BCC" is any chemical that has the potential to cause
			 adverse effects which, upon entering the surface waters, by itself or as its
			 toxic transformation product, accumulates in aquatic organisms by a human
			 health bioaccumulation factor greater than one thousand, after considering
			 metabolism and other physicochemical properties that might enhance or inhibit
			 bioaccumulation, calculated in accordance with the methodology in rule
			 3745-1-41 of the Administrative
			 Code. Chemicals with half-lives of less than eight weeks in the water column,
			 sediment, and biota are not BCCs. The minimum BAF information needed to define
			 an organic chemical as a BCC is either a field-measured BAF or a BAF derived
			 using the BSAF methodology. The minimum BAF information needed to define an
			 inorganic chemical, including an organometal, as a BCC is either a
			 field-measured BAF or a laboratory-measured BCF. Bioaccumulative chemicals of
			 concern include, but are not limited to, chlordane, 4,4'-DDD (p,p'-DDD,
			 4,4'-TDE, p,p'-TDE), 4,4'-DDE (p,p'-DDE), 4,4'-DDT (p,p'-DDT), dieldrin,
			 hexachlorobenzene, hexachlorobutadiene (hexachloro-1,3-butadiene),
			 hexachlorocyclohexanes (BHCs), alphahexachlorocyclohexane (alpha-BHC),
			 beta-hexachlorocyclohexane (beta-BHC), delta-hexachlorocyclohexane (delta-BHC),
			 lindane (gammahexachlorocyclohexane, gamma-BHC), mercury, mirex,
			 octachlorostyrene, PCBs (polychlorinated biphenyls), pentachlorobenzene,
			 photomirex, 2,3,7,8-TCDD (dioxin), 1,2,3,4-tetrachlorobenzene,
			 1,2,4,5-tetrachlorobenzene, and toxaphene.
(17)
			 "Bioconcentration" means the net accumulation of a substance by an aquatic
			 organism as a result of uptake directly from the ambient water through gill
			 membranes or other external body surfaces.
(18) "Bioconcentration
			 factor" or "BCF" means the ratio (in l/kg) of a substance's concentration in
			 the 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.
(19)
			 "Biota-sediment accumulation factor" or "BSAF" means the ratio (in kg of
			 organic carbon/kg of lipid) of a substance's lipid-normalized concentration in
			 the tissue of an aquatic organism to its organic carbon-normalized
			 concentration in surface sediment, in situations where the ratio does not
			 change substantially over time, both the organism and its food are exposed, and
			 the surface sediment is representative of average surface sediment in the
			 vicinity of the organism.
(20) "°C" means degree
			 Celsius.
(21) "Carcinogen"
			 means a substance which causes an increased incidence of benign or malignant
			 neoplasms, or substantially decreases the time to develop neoplasms, in animals
			 or humans. The classification of carcinogens is discussed in rule
			 3745-1-42 of the Administrative
			 Code.
(22) "Chronic aquatic
			 criterion" or "CAC" means an estimate of the highest
			  concentration of a
			 material in
			 the water column (ambient water) to which an aquatic community
			 can be exposed indefinitely without resulting in
			 an unacceptable adverseeffect, including
			 but not limited to
									
			 effects on growth or reproduction. This is the chronic criterion.
(23)
			 "Chronic mixing zone" means the mixture of receiving water and effluent adjacent to a
			 treated or untreated discharge within which the chronic aquatic life, human
			 health, wildlife and agricultural water supply criteria may be exceeded. The
			 chronic aquatic life, human health, wildlife and agricultural water supply
			 criteria 
									are met on the downstream perimeter of the chronic
			 mixing zone.
(24) "Chronic
			 toxicity" means concurrent and delayed adverse effects that occur only as a
			 result of a chronic exposure. Chronic exposure is exposure of an organism for
			 any long period or for a substantial portion of its life span.
(25)
			 "Coldwater fauna" means the species of
			 aquatic animal life adapted to waters
			 having temperatures moderated by contributions from deep or perched aquifers or
			 springs. Water temperatures in such streams typically average less than
			 twenty-one degrees Celsius and rarely exceed twenty-four degrees
			 Celsius.
(26) "Confluence"
			 means the point where two or more bodies of water flow together.
(27)
			 "Criteria" mean elements of water quality standards, expressed as constituent
			 concentrations, levels, or narrative statements, representing a quality of
			 water that supports a particular designated use.
(28) "Criterion
			 continuous concentration" or "CCC" means an estimate of the highest
			 concentration of a material in the water column (ambient water) to which an aquatic community can be
			 exposed indefinitely without resulting in an unacceptable
			 adverse effect, including
			 but not limited to effects on growth or reproduction. This is the chronic
			 criterion.
(29) "Daily average temperature" means the
			 arithmetic mean of multiple temperature measurements to be taken at least once
			 per hour during a twenty-four-hour day.
(30)
									"Daily maximum
			 temperature" means the highest temperature observed in a twenty-four-hour
			 day.
(31) "Degradation"
			 means a lowering of the existing water quality in the surface waters of the
			 state.
(32) "Depuration"
			 means the loss of a substance from an organism as a result of any active or
			 passive process.
(33) "Designated use"
			 means a beneficial use assigned in this chapter
			 for a water body or segment, whether or not that use is
			 being attained. Specific designated uses are defined in rule
			 3745-1-07 of the Administrative
			 Code.
(34) "Director" means
			 the director of the Ohio environmental protection agency
			 or the director's duly authorized
			 representative.
(35) "Discharge" means
			 the addition of any pollutant to the waters of the state from a point
			 source.
(36) "Discharge
			 induced mixing" means the state of mixing between the receiving water and
			 effluent where the processes causing the mixing are induced primarily by the
			 momentum of the effluent as it enters the receiving water.
(37)
			 "E. coli" means Escherichia coli, a specific
			 bacterial species included in the fecal coliform bacteria group, the presence
			 of which in surface waters has been correlated with gastrointestinal illness in
			 swimmers.
(38)
			 "EC50" means the median effective concentration and is a
			 statistically or graphically estimated concentration that is expected to cause
			 one or more specified effects in fifty per cent of a group of organisms under
			 specified conditions.
(39)
									"Endangered species" means any of the following:
(a)
										A native Ohio
			 plant species listed or designated by the Ohio department of natural resources
			 as endangered pursuant to section
			 1518.01 of the Revised
			 Code.
(b)
										An animal species listed or designated as endangered by
			 the Ohio department of natural resources pursuant to section
			 1531.25 of the Revised
			 Code.
(c)
										Any plant or animal species that is native to Ohio or
			 that migrates or is otherwise reasonably likely to occur within the state and
			 which has been listed as endangered pursuant to Section 4 of the Endangered
			 Species Act, 16 U.S.C.
			 section 1533.
(40)
									"Ephemeral
			 feature" means surface water flowing or pooling only in direct response to
			 precipitation, such as rain or snow. "Ephemeral feature" does not include a
			 wetland as defined in section
			 6111.02 of the Revised
			 Code.
(41)
									"Existing uses" means those uses actually attained in
			 the water body on or after November 28, 1975.
(42)
			 "°F" means degree Fahrenheit.
(43) "Fecal coliform"
			 means the portion of the coliform group of bacteria which is present in the
			 intestinal tract of warmblooded animals, and is evidence of the presence of
			 human or animal wastes.
(44) "Final acute
			 value" or "FAV" means either of the following:
(a) A calculated estimate of the
			 concentration of a test material such that ninety-five per cent of the genera
			 (with which acceptable acute toxicity tests have been conducted on the
			 material) have higher GMAVs.
(b)
			 The SMAV of an important or critical species, if the SMAV is lower then the
			 calculated estimate.
(45) "Final chronic
			 value" or "FCV" means any one of the following:
(a) A calculated estimate of the
			 concentration of a test material such that ninety-five per cent of the genera
			 (with which acceptable chronic toxicity tests have been conducted on the
			 material) have higher GMCVs.
(b)
			 The quotient of an FAV divided by an appropriate acute-chronic ratio.
(c) The SMCV of an important and/or critical
			 species, if the SMCV is lower than the calculated estimate or the quotient,
			 whichever is applicable.
(46) "Final plant
			 value" or "FPV" means the lowest plant value obtained with an important aquatic
			 plant species in an acceptable toxicity test for which the concentrations of
			 the test material were measured and the adverse effect was biologically
			 important.
(47) "Food-chain
			 multiplier" or "FCM" means the ratio of a BAF to an appropriate BCF. A
			 food-chain multiplier is meant to account for accumulation of a chemical up the
			 food chain attributable to predation (i.e., between successive trophic
			 levels).
(48) "Genus mean acute
			 value" or "GMAV" means the geometric mean of the SMAVs for the genus.
(49)
			 "Genus mean chronic value" or "GMCV" means the geometric mean of the SMCVs for
			 the genus.
(50) "Geometric mean"
			 means the Nth root of the product of N quantities.
(51) "Great Lakes
			 system" means all the streams, rivers, lakes and other bodies of water within
			 the drainage basin of the Great Lakes within the United States.
(52)
			 "Human cancer criterion" or "HCC" is a human cancer value for a pollutant that
			 meets the minimum data requirements for tier I as specified in rule
			 3745-1-42 of the Administrative
			 Code.
(53) "Human cancer
			 value" or "HCV" is the maximum ambient water concentration of a substance at
			 which a lifetime of exposure from either: drinking the water, consuming fish
			 from the water, and water-related recreation activities; or consuming fish from
			 the water, and water-related recreation activities, will represent a plausible
			 upper-bound risk of contracting cancer of one in one hundred thousand using the
			 exposure assumptions specified in the methodologies for the development of
			 human health criteria and values in rule
			 3745-1-42 of the Administrative
			 Code.
(54) "Human noncancer
			 criterion" or "HNC" is a human noncancer value for a pollutant that meets the
			 minimum data requirements for tier I as specified in rule
			 3745-1-42 of the Administrative
			 Code.
(55) "Human noncancer
			 value" or "HNV" is the maximum ambient water concentration of a substance at
			 which adverse noncancer effects are not likely to occur in the human population
			 from lifetime exposure from either: drinking the water, consuming fish from the
			 water, and water-related recreation activities; or consuming fish from the
			 water and water-related recreation activities, using the methodologies for the
			 development of human health criteria and values in rule
			 3745-1-42 of the Administrative
			 Code.
(56)
									"Lacustuary" is a reach of a given tributary where stream
			 habitat and flow dynamics are affected by lake Erie water levels. In addition
			 to direct lake Erie tributaries, all inland streams and rivers that are
			 tributary to a lake Erie lacustuary are considered a lacustuary in reaches
			 affected by the lake Erie water level.
[Comment: Although "lacustuary" is the
				preferred terminology, the term "estuary" is occasionally used and should be
				considered interchangeable with "lacustuary" when used consistent with this
				definition.]
(57)
									"Lake" means a standing body of open water that is
			 present year round, occurs in a natural depression or is created by
			 artificially blocking or restricting the flow of a stream or by diking or
			 excavating dry land where the resulting water body serves as a public water
			 supply or is on public property with public access.
(58)
			 "Lake Erie drainage basin" means all the streams, rivers, lakes and other
			 bodies of water within the drainage basin of lake Erie and within the United
			 States.
(59)
			 "LC50" means the median lethal concentration and is a
			 statistically or graphically estimated concentration that is expected to be
			 lethal to fifty per cent of a group of organisms under specified
			 conditions.
(60) "Linearized
			 multistage model" means a conservative mathematical model for cancer risk
			 assessment. This model fits linear dose-response curves to low doses. It is
			 consistent with a no-threshold model of carcinogenesis, i.e., exposure to even
			 a very small amount of the substance is assumed to produce a finite increased
			 risk of cancer.
(61) "Lowest observed
			 adverse effect level" or "LOAEL" means the lowest tested dose or concentration
			 of a substance which results in an observed adverse effect in exposed test
			 organisms when all higher doses or concentrations result in the same or more
			 severe effects.
(62)
									"Method detection limit" or "MDL" means the minimum
			 measured concentration of a substance that can be reported with ninety-nine per
			 cent confidence that the measured concentration is distinguishable from method
			 blank results.
(63) "Micrograms per
			 liter (ug/l)" means the micrograms of substance per liter of solution, and is
			 equivalent to 10-9 kilograms per liter or parts per
			 billion, assuming unit density.
(64) "Milligrams per
			 kilogram (mg/kg)" means the milligrams of substance per kilogram of
			 weight.
(65) "Milligrams per
			 liter (mg/l)" means the milligrams of substance per liter of solution, and is
			 equivalent to 10-6 kilograms per liter or parts per
			 million, assuming unit density.
(66) "Mine drainage"
			 means surface or groundwater flowing through or from mines and mine sites. It
			 is usually characterized by concentrations of acidity or alkalinity, various
			 heavy metals, sulfates, and dissolved solids.
(67) "Mixing zone"
			 means an area of a water body contiguous to a treated or untreated wastewater
			 discharge. This discharge is in transit and progressively diluted from the
			 source concentration to the receiving system concentration. The mixing zone
			 is
			 considered a place where wastewater and receiving water mix, not a place where
			 wastes are treated.
(68) "Nanograms per
			 liter (ng/l)" means the nanograms of substance per liter of solution, and is
			 equivalent to 10-12 kilograms per liter or parts per
			 trillion, assuming unit density.
(69) "Natural
			 conditions" mean those conditions that are measured outside the influence of
			 human activities.
(70) "New discharge",
			 for the purposes of implementing the bioaccumulative chemical of concern
			 provisions in Chapter 3745-2 of the Administrative Code, means any of the
			 following:
(a) A discharge of pollutants to a
			 water body from a building, structure, facility or installation, the
			 construction of which commences after December 30, 2002.
(b) A new discharge from an existing
			 discharger that commences after December 30, 2002.
(c) An expanded discharge from an existing
			 discharger that commences after December 30, 2002, except for those expanded
			 discharges resulting from changes in loadings of any BCC within the existing
			 capacity and processes (e.g., normal operational variability, changes in intake
			 water pollutants, increasing the production hours of the facility or adding
			 additional shifts, or increasing the rate of production), and that are covered
			 by the existing Ohio national pollutant discharge elimination system permit.
Not included within the definition of "new discharge" are new
				or expanded discharges of BCCs from a publicly owned treatment works when such
				discharges are necessary to prevent a public health threat to the community
				(e.g., a situation where a community with failing septic systems is connected
				to a POTW to avert a potential public health threat from these failing
				systems). These and all other discharges of BCCs are defined as existing
				discharges.
(71) "No observed
			 adverse effect level" or "NOAEL" means the highest tested dose or concentration
			 of a substance which results in no observed adverse effect in exposed test
			 organisms where higher doses or concentrations result in an adverse
			 effect.
(72) "Nonpoint source"
			 means any source of pollutants other than those defined or designated as point sources.
(73)
			 "Octanol-water partition coefficient" or "Kow" means the ratio of the
			 concentration of a substance in the N-octanol phase to its concentration in the
			 aqueous phase in an equilibrated two-phase octanol-water system. For log Kow,
			 the log of the octanol-water partition coefficient is a base ten
			 logarithm.
(74) "Ohio river
			 drainage basin" means all the streams, rivers, lakes and other bodies of water
			 within the drainage basin of the Ohio river.
(75) "pH" means the
			 negative logarithm of the hydrogen ion activity concentrations when expressed
			 as moles per liter or pH = -log (H+).
(76) "Picograms per
			 liter (pg/l)" means the picograms of substance per liter of solution, and is
			 equivalent to 10-15 kilograms per liter or parts per
			 quadrillion, assuming unit density.
(77) "Point source"
			 means any discernible, confined or discrete conveyance from which a pollutant
			 is or may be discharged to the surface waters of the state.
(78)
			 "Pollutant" means sewage, industrial waste or other waste as defined by
			 divisions (B) to (D) of section
			 6111.01 of the Revised
			 Code.
(79) "Pollution
			 prevention alternatives assessment" means an analysis that identifies any
			 cost-effective pollution prevention alternatives and techniques that are
			 available to the discharger, and that would reduce the extent to which the
			 increased loading results in a lowering of water quality. A pollution
			 prevention alternatives analysis 
									demonstrates a good faith
			 effort by the discharger to review equipment or technology modifications,
			 process or procedure modifications, reformulation or redesign of products,
			 substitution of raw materials and improvements to housekeeping. The discharger
			 will
			 not need to implement a pollution prevention alternative if it is not
			 technically or economically feasible.
(80)
									"Public water
			 system" means the same as the definition in rule
			 3745-81-01 of the Administrative
			 Code.
(81)
									"Publicly owned treatment works" or "POTW" means any
			 device or system used in the treatment (including recycling and reclamation) of
			 domestic sewage or industrial waste of a liquid nature that is owned by a
			 municipality, county, or state entity or any public body created under state
			 law that has authority over disposal of sewage.
(82)
									"Qualitative
			 habitat evaluation index" or "QHEI" means an assessment methodology of the
			 principal physical and riparian stream habitat features that affect fish
			 communities and other aquatic life.
(83) "Receiving
			 waters" mean the surface waters of the state into which point and nonpoint
			 sources flow.
(84) "Relative source
			 contribution" or "RSC" means the factor (percentage) used in calculating a HNV
			 or HNC to account for all sources of exposure to a contaminant. The RSC
			 reflects the per cent of total exposure which can be attributed to surface
			 water through water intake and fish consumption.
(85) "Representative
			 aquatic species" mean those organisms, either natural or introduced, which
			 presently exist or have existed in the surface waters of the state prior to
			 July 1, 1977, with the exception of those banned species outlined in rule
			 1501:31-19-01 of the
			 Administrative Code. In addition, it may include any species that are legally
			 introduced into the surface waters of the state. Aquatic species designated as
			 representative  satisfy one or more of
			 the following:
(a) Species that are
			 particularly vulnerable to the existing or proposed environmental impact in
			 question.
(b) Species that are
			 commercially or recreationally valuable.
(c) Species that are threatened, rare, or
			 endangered.
(d) Species that are
			 critical to the structure and function of the aquatic community.
(e) Species whose presence is causally
			 related to the existing or proposed environmental impact under
			 examination.
(f) Species that are
			 potentially capable of becoming localized nuisance species.
(g) Species that are representative of the
			 ecological, behavioral, and physiological requirements and characteristics of
			 species determined in paragraphs (B)(77)(a) to (B)(77)(f) of this rule, but
			 which themselves might not be representative.
(86)
			 "Risk associated dose" or "RAD" means a dose of a known or presumed
			 carcinogenic substance in (mg/kg) /day which, over a lifetime of exposure, is
			 estimated to be associated with a plausible upper bound incremental cancer risk
			 equal to one in one hundred thousand.
(87) "Slope factor" or
			 "Q1*" means the incremental
			 rate of cancer development calculated through use of a linearized multistage
			 model or other appropriate model. It is expressed in (mg/kg/day) of exposure to
			 the chemical in question.
(88) "Species mean
			 acute value" or "SMAV" means the geometric mean of the results of all
			 acceptable flow-through acute toxicity tests (for which the concentrations of
			 the test material were measured) with the most sensitive tested life stage of
			 the species. For a species for which no such result is available for the most
			 sensitive tested life stage, the SMAV is the geometric mean of the results of
			 all acceptable acute toxicity tests with the most sensitive tested life
			 stage.
(89) "Species mean
			 chronic value" or "SMCV" means the geometric mean of the results of all
			 acceptable life-cycle and partial life-cycle toxicity tests with the species;
			 for a species of fish for which no such result is available, the SMCV is the
			 geometric mean of all acceptable early life-stage tests.
(90)
			 "Structure-activity relationship" or "SAR" means a mathematical relationship
			 between a property (i.e., biological activity or response) of a chemical and a
			 number of descriptors of the chemical. These descriptors are chemical or
			 physical characteristics obtained experimentally or predicted from the
			 structure of the chemical.
(91) "Surface waters
			 of the state" or "water bodies" mean all streams, lakes, reservoirs, ponds,
			 marshes, wetlands or other waterways which are situated wholly or partially
			 within the boundaries of the state, except those private waters which do not
			 combine or effect a junction with natural surface or underground waters. Waters
			 defined as sewerage system, treatment works or disposal system in section
			 6111.01 of the Revised Code are
			 not included.
(92) "Thermal mixing
			 zone" means that portion of a water body into which waste heat is discharged
			 and assimilated, and within which the average and maximum daily average
			 temperatures do not apply, except as prescribed by this chapter.
(93)
			 "Threatened  species"
			 means any of the following:
(a)
										A native Ohio
			 plant species listed or designated by the Ohio department of natural resources
			 as threatened with extirpation pursuant to section
			 1518.01 of the Revised
			 Code.
(b)
										An animal species listed or designated
										as threatened with statewide
			  extinction
										by the Ohio department of natural resources pursuant to
			 section 1531.25 of the Revised
			 Code.
(c)
										Any plant or animal species that is native to Ohio or
			 that migrates or is otherwise reasonably likely to occur within the state and
			 which has been listed as threatened pursuant to Section 4 of the Endangered
			 Species Act, 16 U.S.C.
			 section 1533.
(94)
			 "Threshold effect" means an effect of a substance for which there is a
			 theoretical or empirically established dose or concentration below which the
			 effect does not occur.
(95) "Tier I criteria"
			 mean numeric values derived by use of the tier I methodologies specified in
			 rules 3745-1-40,
			 3745-1-42 and
			 3745-1-43 of the Administrative
			 Code, that either have been adopted as numeric criteria into a water quality
			 standard or are used to implement narrative water quality criteria.
(96)
			 "Tier II values" means numeric values derived by use of the tier II
			 methodologies specified in rules
			 3745-1-40 and
			 3745-1-42 of the Administrative
			 Code that are used to implement narrative water quality criteria.
(97)
									"Total maximum
			 daily load" or "TMDL" means the sum of the existing or projected point source,
			 nonpoint source, and background loads for a pollutant to a specified watershed,
			 water body, or water body segment. A TMDL sets and allocates the maximum amount
			 of a pollutant that may be introduced into the water and still ensures
			 attainment and maintenance of water quality standards.
(98)
			 "Toxic substances" mean any substances which can cause death, disease,
			 behavioral abnormalities, cancer, genetic mutations, physiological or
			 reproductive malfunction or physical deformities in any organism or its
			 offspring, or which can become poisonous after concentration in the food chain
			 or in combination with other substances.
(99)
			 "Tributary" means a stream flowing into a larger body of water.
(100)
			 "Uncertainty factor" or "UF" means one of several numeric factors used in
			 operationally deriving criteria from experimental data to account for the
			 quality or quantity of the available data.
(101) "Uptake" means
			 acquisition of a substance from the environment by an organism as a result of
			 any active or passive process.
(102) "Use
			 attainability analysis" means a structured scientific assessment of the factors
			 affecting the attainment of the use which may include physical, chemical,
			 biological, and economic factors.
(103) "Warmwater
			 fauna"
			 means 
									the species of 
									aquatic animal
			 life that occur where water temperature is
			 primarily influenced by ambient air temperature; habitat and other
			 characteristics also influence their range and propagation.
(104)
									"Wasteload
			 allocation" or "WLA" means the portion of a receiving water's loading capacity
			 that is allocated to one of its existing or future point sources of pollution.
			 In the absence of a TMDL or TMDL assessment and remediation plan, a WLA is the
			 allocation for an individual point source that ensures that the level of water
			 quality to be achieved by the point source is derived from and complies with
			 all applicable water quality standards.
(105) "Water bodies"
			 or "waters of the state" mean all streams, lakes, ponds, marshes, watercourses,
			 waterways, wells, springs, irrigation systems, drainage systems, and all other
			 bodies or accumulations of water, surface and underground, natural or
			 artificial, that are situated wholly or partly within,
			 or border upon, this state, or are within its jurisdiction, except those
			 private waters that do not combine or effect a junction with natural surface or
			 underground waters. "Waters of the state" does not
			 include an ephemeral feature for which the United States army corps of
			 engineers lacks the authority to issue a permit under
			 33 U.S.C. section
			 1344.
(106) "Water quality
			 standards" means the rules set forth in this chapter establishing stream use
			 designations and water quality criteria protective of such uses for the surface
			 waters of the state.
(107) "Wetlands" means
			 those areas that are inundated or saturated by surface or ground water at a
			 frequency and duration that are sufficient to support, and that under normal
			 circumstances do support, a prevalence of vegetation typically adapted for life
			 in saturated soil conditions. "Wetlands" includes swamps, marshes, bogs, and
			 similar areas that are delineated in accordance with the 1987 United States
			 army corps of engineers wetland delineation manual and any other procedures and
			 requirements adopted by the United States army corps of engineers for
			 delineating wetlands.
(108)
									"Whole effluent toxicity" or "WET" means the aggregate
			 toxic effect of an effluent measured directly by a toxicity test where the test
			 results are based on acute (lethal) or chronic (lethal and sublethal)
			 endpoints.