§611.310. State-Only Maximum Contaminant Levels (MCLs) for Organic Chemical Contaminants

The following are State-only MCLs for organic chemical contaminants.  These State-only MCLs apply to all CWSs.  A supplier must calculate compliance with these State-only MCLs in subsections (a) and (b) under Subpart O. 

 

Contaminant	MCL (mg/L)
Aldrin	0.001
DDT	0.05
Dieldrin	0.001
Heptachlor	0.0001
Heptachlor epoxide	0.0001
2,4-D	0.01

 

BOARD NOTE:  This Section originally derived from 40 CFR 141.12 (1992). USEPA removed the last entries from subsections (a) and (b) and marked them reserved at 57 Fed. Reg. 31838 (July 17, 1992).  USEPA entirely removed 40 CFR 141.12 and marked it "reserved" at 71 Fed. Reg. 388 (Jan. 4, 2006).  USEPA's organic chemical MCLs are now at 40 CFR 141.61, which corresponds with Section 611.311.  Different MCLs for heptachlor, heptachlor epoxide, and 2,4-D appear in both this Section and Section 611.311.  The heptachlor, heptachlor epoxide, and 2,4-D MCLs in this Section are Illinois limitations that are more stringent than the federal requirements.  However, detection of these contaminants or violation of the federally-derived revised MCLs in Section 611.311 imposes more stringent monitoring, reporting, and notice requirements.

 

(Source:  Amended at 47 Ill. Reg. 16486, effective November 2, 2023)