Illinois Administrative Code (Last Updated: March 27, 2024) |
TITLE35. ENVIRONMENTAL PROTECTION |
PART302. WATER QUALITY STANDARDS |
SUBPARTB. GENERAL USE WATER QUALITY STANDARDS |
§302.208. Numeric Standards for Chemical Constituents
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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
Constituent
AS (µg/L)
CS (µg/L)
Arsenic (trivalent, dissolved)
360 x 1.0* = 360
190 x 1.0* = 190
Boron (total)
40,100
7,600
Cadmium (dissolved)
*
*
where A = -2.918 and
B = 1.128
where A = -3.490 and
B = 0.7852
Chromium (hexavalent, total)
16
11
Chromium (trivalent, dissolved)
where A = 3.688 and
B = 0.8190
where A = 1.561 and
B = 0.8190
Copper (dissolved)
where A = -1.464 and
B = 0.9422
where A = -1.465 and
B = 0.8545
Cyanide**
22
5.2
Fluoride (total)
, but must not exceed 4.0 mg/L
where A = 6.7319 and
B = 0.5394
where A = 6.0445 and
B = 0.5394
Lead (dissolved)
where A = -1.301 and
B = 1.273
where A = -2.863 and
B = 1.273
Manganese (dissolved)
0.9812*
0.9812*
where A = 4.9187 and
B = 0.7467
where A = 4.0635 and
B = 0.7467
Mercury (dissolved)
2.6 x 0.85* = 2.2
1.3 x 0.85* = 1.1
Nickel (dissolved)
where A = 0.5173 and
B = 0.8460
where A = -2.286 and
B = 0.8460
TRC
19
11
Zinc (dissolved)
where A = 0.9035 and
B = 0.8473
where A = -0.4456 and B = 0.8473
Benzene
4200
860
Ethylbenzene
150
14
Toluene
2000
600
Xylene(s)
920
360
where:
µg/L
=
microgram per liter
ex
=
base of natural logarithms raised to the x-power
ln(H)
=
natural logarithm of hardness (in mg/L as CaCO3)
*
=
conversion factor multiplier for dissolved metals
**
=
standard to be evaluated using either of the following USEPA approved methods, incorporated by reference at 35 Ill. Adm. Code 301.106: Method OIA-1677, DW: Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry, January 2004, Document Number EPA-821-R-04-001 or Cyanide Amenable to Chlorination, Standard Methods 4500-CN-G (40 CFR 136.3)
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
(Source: Amended at 47 Ill. Reg. 4437, effective March 23, 2023)