Indiana Administrative Code › Title 327 - WATER POLLUTION CONTROL DIVISION › Article 2 - WATER QUALITY STANDARDS › Rule 1 - Water Quality Standards Applicable to All State Waters Except Waters of the State Within the Great Lakes System › Section 1-8.5 - Determination of the human life cycle safe concentration (HLSC)

Current through July 10, 2024
Authority: IC 13-1-3-7; IC 13-7-7-5
Affected: IC 13-1-3-7; IC 13-7-7-5
Sec. 8.5.
The concentration to protect public health from threshold
				  effect toxicants is the human life cycle safe concentration (HLSC). The minimum
				  toxicity data requirement for derivation of an HLSC shall consist of an acute
				  oral LD50 for rats. The HLSC shall be derived in the
				  following manner:
(1) The HLSC shall
				be derived from appropriate toxicological data using the following formula:
Click here
				  to view
Where: MgT = maximum milligrams of toxicant per day causing
				  no adverse effects to humans when ingested daily for lifetime
WC = volume of water consumed daily in liters (two (2) liters
				  per day for surface water protected for drinking water supply; one-hundredth
				  (0.01) liter per day for surface water not protected for drinking water
				  supply)
F = sixty-five ten-thousandths (0.0065) kilograms per day,
				  daily consumption of fish by humans
BCF = bioconcentration factor in
mg/kg
mg/1
as determined in section 8.7 of this rule mg/1
(2) The MgT shall be derived by
				one (1) of the following methods depending on the type and quality of the
				toxicity data base:
(A) If a scientifically
				valid maximum contaminant level (MCL) from the national interim primary
				drinking water regulations is available:
Click here
				  to view
Where: Vh = two (2) liters per day,
				  volume of water consumed daily by humans
(B) If a chronic, subchronic, or subacute no
				observable adverse effect level (NOAEL) for humans exposed to toxicant
				contaminated drinking water is available:
Click here
				  to view
Where: U = uncertainty factor (U = 10 - 100)
(C) If a scientifically valid
				acceptable daily intake (ADI) is available from the federal Food and Drug
				Administration regulations: MgT = ADI.
(D) If a chronic, subchronic, or subacute
				NOAEL from mammalian test species exposed to toxicant contaminated drinking
				water is available:
Click here
				  to view
Where: Vw = volume of water consumed
				  daily by test animal (liters per day)
Wa = weight of test animal (kg)
Wh = seventy (70) kilograms, weight of
				  human
B = uncertainty factor (B = 100-1,000 depending on quality of
				  study)
(E) If a chronic,
				subchronic, or subacute NOAEL from mammalian test species exposed to toxicant
				contaminated food is available:
Click here
				  to view
Where: C = daily food consumption expressed as a fraction of
				  the animal's body weight
(F) If a chronic, subchronic, or subacute
				NOAEL from mammalian test species exposed to toxicant by gavage is available:
Click here
				  to view
Where: Fw = fraction of days dosed per
				  week
(G) If an oral rat
				LD50 is available:
Click here
				  to view
Where: M = one-ten thousandth (0.0001), acute to chronic
				  application factor
(H) If
				an acceptable NOAEL is lacking, the lowest observable adverse effect level
				(LOAEL) may be substituted in some cases for NOAEL, with an additional
				uncertainty factor of one (1) to ten (10).
(I) HLSCs are best derived from data
				involving oral exposure. However, if available oral data are insufficient, it
				may be useful to use data from other exposure routes. Use of such data will
				depend on the specific pharmacokinetic and toxicological properties of each
				chemical.
(J) On the basis of
				available information, the HLSC is evaluated as to whether it is consistent
				with sound scientific judgment. If not, the commissioner will direct the
				evaluation of appropriate modifications of these procedures.