Michigan Administrative Code › Department - Environmental Quality › Water Resources Division › Water Resources Protection › Part 8 - WATER QUALITY-BASED EFFLUENT LIMIT DEVELOPMENT FOR TOXIC SUBSTANCES › Section R. 323.1203 - Definitions; A to L

Current through Vol. 24-12, July 15, 2024
Rule 1203. As used in this part:
(a) "Acute-chronic ratio (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.
(b) "Acute toxicity"
				  means an adverse effect that results from an acute exposure which occurs within
				  any short observation period and which usually does not constitute a
				  substantial portion of the life span of the organism.
(c) "Acute toxic unit (TUa)" means 100/LC50
				  where the LC50 is determined from a whole effluent toxicity (WET) test which
				  produces a result that is statistically or graphically estimated to be lethal
				  to 50% of the test organisms.
(d)
				  "Aquatic life value" means a tier I or tier II value developed under R
				  323.1057(2).
(e) "Bioaccumulation
				  equivalency factor (BEF)" means the bioaccumulation potential for the
				  toxicologically important chlorinated dibenzo-p-dioxins and chlorinated
				  dibenzo-p-furans relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD)
				  for use in calculating 2,3,7,8-TCDD toxicity equivalency concentrations in
				  water as the 2,3,7,8-TCDD toxicity equivalency concentrations relate to
				  deriving human health water quality values.
(f) "Bioaccumulation factor (BAF)" means the
				  ratio, in liters per kilogram, of a substance's concentration in tissue of an
				  aquatic organism to its concentration in the ambient water where both the
				  organism and its food are exposed and the ratio does not change substantially
				  over time.
(g) "Bioaccumulative
				  chemical of concern (BCC)" means a chemical which, upon entering the surface
				  waters, by itself or as its toxic transformation product, accumulates in
				  aquatic organisms by a human health bioaccumulation factor (BAF) of more than
				  1000 derived after considering metabolism and other physiochemical properties
				  that might enhance or inhibit bioaccumulation. The human health bioaccumulation
				  factor shall be derived according to R 323.1057(5). Chemicals with half-lives
				  of less than 8 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 biota-sediment accumulation
				  factor (BSAF) methodology. The minimum BAF information needed to define an
				  inorganic chemical as a BCC, including an organometal, is either a
				  field-measured BAF or a laboratory-measured bioconcentration factor (BCF). The
				  BCCs to which these rules apply are identified in table 5 of R
				  323.1057.
(h) "Bioconcentration
				  factor (BCF)" means the ratio, in liters per kilogram, of a substance's
				  concentration 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.
(i) "Biota-sediment accumulation factor
				  (BSAF)" means the ratio, in kilograms of organic carbon per kilogram of lipid,
				  of a substance's lipid-normalized concentration in 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.
(j) "Carcinogen" means a substance which
				  causes an increased incidence of benign or malignant neoplasms in animals or
				  humans or that substantially decreases the time in which neoplasms develop in
				  animals or humans.
(k)
				  "Chemical-specific water quality-based effluent limit" means water
				  quality-based effluent limits that are based on an individual
				  chemical.
(l) "Chronic toxicity"
				  means a concurrent and delayed adverse effect that occurs only as a result of a
				  chronic exposure.
(m) "Chronic
				  toxic unit (TUc)" means 100/MATC or 100/IC25, where the maximum acceptable
				  toxicant concentration (MATC) and IC25 are expressed as a percent effluent in
				  the test medium.
(n) "Clean water
				  act" means the federal water pollution control act codified at 33 U.S.C.
				  §1251 et seq., as amended.
(o)
				  "Daily maximum water quality-based effluent limit" means an effluent specific
				  water quality-based effluent limit in an NPDES permit developed to protect
				  aquatic life from acute chemical specific or whole effluent toxicity.
(p) "Department" means the director of the
				  Michigan department of environmental quality, or his or her designee to whom
				  the director delegates a power or duty by written instrument.
(q) "Detection level" means the lowest
				  concentration or amount of the target analyte that can be determined to be
				  different from zero by a single measurement at a stated level of
				  probability.
(r) "Discharge-induced
				  mixing" means the mixing of a discharge and receiving water that occurs due to
				  discharge momentum and buoyancy up to the point where mixing is controlled by
				  ambient turbulence.
(s) "Dissolved
				  metal" means the concentration of a metal that will pass through a 0.45-mm
				  membrane filter.
(t) "Existing
				  discharge" means any building, structure, facility, or installation from which
				  there is or may be a discharge of toxic substances to the surface waters of the
				  state that is not a new discharge.
(u) "Final acute value (FAV)" means the level
				  of a chemical or mixture of chemicals that does not allow the mortality or
				  other specified response of aquatic organisms to exceed 50% when exposed for 96
				  hours, except where a shorter time period is appropriate for certain species.
				  The FAV shall be calculated under R 323.1057(2) if appropriate for the
				  chemical.
(v) "Human cancer value
				  (HCV)" means 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 conducting water-related recreation activities or consuming fish
				  from the water and conducting water-related recreation activities will
				  represent a plausible upper bound risk of contracting cancer of 1 in 100,000
				  using the exposure assumptions and methodology specified in R
				  323.1057(4).
(w) "Human noncancer
				  value (HNV)" means 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 through either drinking the water, consuming fish from
				  the water, and conducting water-related recreation activities or consuming fish
				  from the water and conducting water-related recreation activities using the
				  exposure assumption and methodology in R 323.1057(4).
(x) "Intake toxic substance" means the amount
				  of a toxic substance that is present in surface or groundwaters of the state at
				  the time the toxic substance is withdrawn from the waters by the discharger or
				  present in the water provided to the discharger by another facility.
(y) "Intermittent wet-weather point source"
				  means a point source discharge that occurs as a result of a rainfall or
				  snowmelt event. An intermittent wet-weather point source includes a treated or
				  untreated combined sewer overflow, but does not include a storm water discharge
				  that is mixed with other industrial or commercial wastewater or an increased
				  discharge from a municipal wastewater treatment plant due to a rainfall or
				  snowmelt event.
(z) "IC25" means
				  the toxicant concentration that would cause a 25% reduction in a nonquantal
				  biological measurement for the test population.
(aa) "LC50" means a statistically or
				  graphically estimated concentration that is expected to be lethal to 50% of a
				  group of organisms under specified conditions.
(bb) "Load allocation" means the portion of a
				  receiving water's loading capacity that is attributed to existing or future
				  nonpoint sources, including natural background sources.
(cc) "Loading capacity" means the greatest
				  amount of pollutant loading that a water can receive without violating water
				  quality standards.
(dd) "Lotic"
				  means surface waters of the state that exhibit flow.