Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 302 - WATER QUALITY STANDARDS › Subpart B - GENERAL USE WATER QUALITY STANDARDS › Section 302.208 - Numeric Standards for Chemical Constituents

Current through Register Vol. 48, No. 28, July 12, 2024
a) The acute standard (AS) for the chemical
				constituents listed in subsection (e) must not be exceeded at any time except
				for those waters for which a zone of initial dilution (ZID) has been approved
				by the Agency under Section
				302.102.
b) The chronic standard (CS) for the chemical
				constituents listed in subsection (e) must not be exceeded by the arithmetic
				average of at least four consecutive samples collected over any period of at
				least four days, except for those waters in which the Agency has approved a
				mixing zone or in which mixing is allowed under 35 Ill. Adm. Code 302.102. The
				samples used to demonstrate attainment or lack of attainment with a CS must be
				collected in a manner that assures an average representative of the sampling
				period. For the chemical constituents that have water quality-based standards
				dependent upon hardness, the chronic water quality standard will be calculated
				according to subsection (e) using the hardness of the water body at the time
				the sample was collected. To calculate the attainment status of chronic
				standards, the concentration of the chemical constituent in each sample is
				divided by the calculated water quality standard for the sample to determine a
				quotient. The water quality standard is attained if the mean of the sample
				quotients is less than or equal to one for the duration of the averaging
				period.
c) The human health
				standard (HHS) for the chemical constituents listed in subsection (f) must not
				be exceeded when the streamflow is at or above the harmonic mean flow under
				Section 302.658, nor must an annual
				average, based on at least eight samples collected in a manner representative
				of the sampling period, exceed the HHS except for those waters in which the
				Agency has approved a mixing zone or in which mixing is allowed under Section
				302.102.
d) The standard for the
				chemical constituents of subsections (g) and (h) must not be exceeded at any
				time except for those waters in which the Agency has approved a mixing zone or
				in which mixing is allowed under Section 302.102.
e) Numeric Water Quality Standards for the
				Protection of Aquatic Organisms
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f) Numeric Water Quality Standard for the
				Protection of Human Health
Constituent
(µg/L)
Mercury (total)
0.012
Benzene
310
where:
µg/L
=
micrograms per liter
g)
				Single-value standards apply at the following concentrations for these
				substances:
Constituent
Unit
Standard
Barium (total)
mg/L
5.0
Chloride (total)
mg/L
500
Iron (dissolved)
mg/L
1.0
Phenols
mg/L
0.1
Selenium (total)
mg/L
1.0
Silver (total)
µg/L
5.0
where:
mg/L
=
milligram per liter and
µg/L
=
microgram per liter
h)
				Water quality standards for sulfate are as follows:
1) At any point where water is withdrawn or
				accessed for purposes of livestock watering, the average of sulfate
				concentrations must not exceed 2,000 mg/L when measured at a representative
				frequency over a 30-day period.
2)
				The results of the following equations provide sulfate water quality standards
				in mg/L for the specified ranges of hardness (in mg/L as
				CaCO3) and chloride (in mg/L) and must be met at all
				times:
A) If the hardness concentration of
				receiving waters is greater than or equal to 100 mg/L but less than or equal to
				500 mg/L, and if the chloride concentration of waters is greater than or equal
				to 25 mg/L but less than or equal to 500 mg/L, then:
C = [1276.7 +
				  5.508(hardness)
				  - 1.457(chloride)]
				  * 0.65
where:
C
=
sulfate concentration
B) If
				the hardness concentration of waters is greater than or equal to 100 mg/L but
				less than or equal to 500 mg/L, and if the chloride concentration of waters is
				greater than or equal to 5 mg/L but less than 25 mg/L, then:
C = [-57.478 +
				  5.79(hardness)
				  + 54.163(chloride)]
				  * 0.65
where:
C
=
sulfate concentration
3) The following sulfate standards must be
				met at all times when hardness (in mg/L as CaCO3) and
				chloride (in mg/L) concentrations other than specified in subsection (h)(2) are
				present:
A) If the hardness concentration of
				waters is less than 100 mg/L or chloride concentration of waters is less than 5
				mg/L, the sulfate standard is 500 mg/L.
B) If the hardness concentration of waters is
				greater than 500 mg/L and the chloride concentration of waters is 5 mg/L or
				greater, the sulfate standard is 2,000 mg/L.
C) If the combination of hardness and
				chloride concentrations of existing waters are not reflected in subsection
				(h)(3)(A) or (B), the sulfate standard may be determined in a site-specific
				rulemaking under section 303(c) of the Federal Water Pollution Control Act of
				1972 (Clean Water Act), 33
				U.S.C. 1313(c), and Federal
				Regulations at 40 CFR
				131.10(j)(2).