Derived Water Quality Criteria
Narrative standards exist in Illinois Pollution Control Board (IPCB)
regulations at 35 IAC 302.210 and in Subpart F for General Use Waters
and at 302.540 and elsewhere in Subpart E for Lake Michigan Basin Waters.
Lake Michigan Basin waters include all tributaries of Lake Michigan,
harbors and open waters of the Illinois portion of the lake. General
Use Waters cover all other waters of the state except those waters
designated as Secondary Contact and Indigenous Aquatic Life Use Waters,
which consist of several canals and rivers in the Chicago area. A
narrative standard also exists for Secondary Contact Waters but derived
criteria are not yet included in the list of criteria at this site.
The narrative standards allow the Illinois EPA to derive numeric
water quality criteria values for any substance that does not already
have a numeric standard in the IPCB regulations. These criteria
serve to protect aquatic life, human health or wildlife, although
wildlife based derived criteria have not yet been derived. The following
list provides the criteria derived to date. The reader should pay
particular attention to the "Notes for Table Headings"
found below the list, because many criteria are provided with important
comments. For example, some criteria have been derived from a less
than ideal data set yet we include these values because we find
it desirable to have some numeric indication of toxicity. These
values may not be suitable for use in a regulatory setting, however.
Criteria that have been used to limit discharges of a substance
in an NPDES permit are published quarterly in the
Register. All values on this list are subject to recalculation
at any time. Illinois EPA will endeavor to keep this list updated.
References to criteria in this list should include the date contained
in the list heading.