MCLs for Organic Chemical Contaminants

Section 611 TITLE 35: ENVIRONMENTAL PROTECTION SUBTITLE F: PUBLIC WATER SUPPLIES CHAPTER I: POLLUTION CONTROL BOARD PART 611 PRIMARY DRINKING WATER STANDARDS SECTION 611.311 MCLS FOR ORGANIC CHEMICAL CONTAMINANTS Section 611.311  MCLs for Organic Chemical Contaminants a)         Maximum Contaminant Levels for Volatile Organic Chemical Contaminants. The MCLs for VOCs apply to CWS suppliers and NTNCWS suppliers: CAS No. Contaminant MCL (mg/L) 71-43-2 Benzene 0.005 56-23-5 Carbon tetrachloride 0.005 95-50-1 o-Dichlorobenzene 0.6 106-46-7 p-Dichlorobenzene 0.075 107-06-2 1,2-Dichloroethane 0.005 75-35-4 1,1-Dichloroethylene 0.007 156-59-2 cis-1,2-Dichloroethylene 0.07 156-60-5 trans-1,2-Dichloroethylene 0.1 75-09-2 Dichloromethane (methylene chloride) 0.005 78-87-5 1,2-Dichloropropane 0.005 100-41-4 Ethylbenzene 0.7 108-90-7 Monochlorobenzene 0.1 100-42-5 Styrene 0.1 127-18-4 Tetrachloroethylene 0.005 108-88-3 Toluene 1 120-82-1 1,2,4-Trichlorobenzene 0.07 71-55-6 1,1,1-Trichloroethane 0.2 79-00-5 1,1,2-Trichloroethane 0.005 79-01-6 Trichloroethylene 0.005 75-01-4 Vinyl chloride 0.002 1330-20-7 Xylenes (total) 10 b)         USEPA, under section 1412 of SDWA identifies in this subsection (b) granular activated carbon (GAC), packed tower aeration (PTA), or oxidation (OX) as BAT, treatment technique, or other means available for achieving compliance with the MCLs for VOCs, and SOCs in subsections (a) and (c) except for per-and polyfluoroalkyl substances (PFAS), as indicated: CAS No. Contaminant BAT 15972-60-8 Alachlor GAC 116-06-3 Aldicarb* GAC 1646-87-4 Aldicarb sulfone* GAC 1646-87-3 Aldicarb sulfoxide* GAC 1912-24-9 Atrazine GAC 71-43-2 Benzene GAC, PTA 50-32-8 Benzo(a)pyrene GAC 1563-66-2 Carbofuran GAC 56-23-5 Carbon tetrachloride GAC, PTA 57-74-9 Chlordane GAC 94-75-7 2,4-D GAC 75-99-0 Dalapon GAC 96-12-8 Dibromochloropropane GAC, PTA 95-50-1 o-Dichlorobenzene GAC, PTA 106-46-7 p-Dichlorobenzene GAC, PTA 107-06-2 1,2-Dichloroethane GAC, PTA 156-59-2 cis-1,2-Dichloroethylene GAC, PTA 156-60-5 trans-1,2-Dichoroethylene GAC, PTA 75-35-4 1,1-Dichloroethylene GAC, PTA 75-09-2 Dichloromethane PTA 78-87-5 1,2-Dichloropropane GAC, PTA 103-23-1 Di(2-ethylhexyl)adipate GAC, PTA 117-81-7 Di(2-ethylhexyl)phthalate GAC 88-85-7 Dinoseb GAC 85-00-7 Diquat GAC 145-73-3 Endothall GAC 72-20-8 Endrin GAC 106-93-4 Ethylene dibromide (EDB) GAC, PTA 100-41-4 Ethylbenzene GAC, PTA 1071-53-6 Glyphosate OX 76-44-8 Heptachlor GAC 1024-57-3 Heptachlor epoxide GAC 118-74-1 Hexachlorobenzene GAC 77-47-3 Hexachlorocyclopentadiene GAC, PTA 58-89-9 Lindane GAC 72-43-5 Methoxychlor GAC 108-90-7 Monochlorobenzene GAC, PTA 23135-22-0 Oxamyl GAC 87-86-5 Pentachlorophenol GAC 1918-02-1 Picloram GAC 1336-36-3 Polychlorinated biphenyls (PCB) GAC 122-34-9 Simazine GAC 100-42-5 Styrene GAC, PTA 1746-01-6 2,3,7,8-TCDD GAC 127-18-4 Tetrachloroethylene GAC, PTA 108-88-3 Toluene GAC, PTA 8001-35-2 Toxaphene GAC 120-82-1 1,2,4-trichlorobenzene GAC, PTA 71-55-6 1,1,1-Trichloroethane GAC, PTA 79-00-5 1,1,2-trichloroethane GAC, PTA 79-01-6 Trichloroethylene GAC, PTA 93-72-1 2,4,5-TP GAC 75-01-4 Vinyl chloride PTA 1330-20-7 Xylene GAC, PTA *See the Board note at the end of this Section. c)         The following maximum contaminant levels (MCLs) in Tables 1 and 2 to subsection (c) for synthetic organic contaminants apply to CWS and NTNCWS suppliers; Table 2 also contains health-based water concentrations (HBWCs) for selected per-and poly-fluoroalkyl substances (PFAS) used in calculating the Hazard Index. 1)         MCLs for SOCs (except for PFAS) apply to CWS and NTNCWS suppliers: CAS Number Contaminant MCL (mg/L) 15972-60-8 Alachlor 0.002 116-06-3 Aldicarb* 0.003 1646-87-4 Aldicarb sulfone* 0.002 1646-87-3 Aldicarb sulfoxide* 0.004 1912-24-9 Atrazine 0.003 50-32-8 Benzo(a)pyrene 0.0002 1563-66-2 Carbofuran 0.04 57-74-9 Chlordane 0.002 94-75-7 2,4-D 0.07 75-99-0 Dalapon 0.2 96-12-8 Dibromochloropropane 0.0002 103-23-1 Di(2-ethylhexyl)adipate 0.4 117-81-7 Di(2-ethylhexyl)phthalate 0.006 88-85-7 Dinoseb 0.007 85-00-7 Diquat 0.02 145-73-3 Endothall 0.1 72-20-8 Endrin 0.002 106-93-4 Ethylene dibromide 0.00005 1071-53-6 Glyphosate 0.7 76-44-8 Heptachlor 0.0004 1024-57-3 Heptachlor epoxide 0.0002 118-74-1 Hexachlorobenzene 0.001 77-47-4 Hexachlorocyclopentadiene 0.05 58-89-9 Lindane 0.0002 72-43-5 Methoxychlor 0.04 23135-22-0 Oxamyl (Vydate) 0.2 87-86-5 Pentachlorophenol 0.001 1918-02-1 Picloram 0.5 1336-36-3 Polychlorinated biphenyls (PCBs) 0.0005 122-34-9 Simazine 0.004 1746-01-6 2,3,7,8-TCDD (Dioxin) 0.00000003 8001-35-2 Toxaphene 0.003 93-72-1 2,4,5-TP 0.05 * See the Board note at the end of this Section. 2)         MCLs and HBWCs for PFAS apply to CWS and NTNCWS suppliers: CAS Number Contaminant MCL (mg/ L) HBWC (mg/l) Not applicable Hazard Index PFAS (HFPO-DA, PFBS, PFHxS, and PFNA) 1 (unitless) 1 Not applicable 122499-17-6 HFPO-DA 0.00001 0.00001 45187-15-3 PFBS No Individual MCL 0.002 108427-53-8 PFHxS 0.00001 0.00001 72007-68-2 PFNA 0.00001 0.00001 45285-51-6 PFOA 0.0000040 Not applicable 45298-90-6 PFOS 0.0000040 Not applicable 1 The PFAS Mixture Hazard Index (HI) is the sum of component hazard quotients (HQs), which are calculated by dividing the measured component PFAS concentration in water by the relevant health-based water concentration when expressed in the same units (shown in ng/l for simplification). The HBWC for PFHxS is 10 ng/l; the HBWC for HFPO-DA is 10 ng/l; the HBWC for PFNA is 10 ng/l; and the HBWC for PFBS is 2000 ng/l.  A PFAS Mixture Hazard Index greater than 1 (unitless) indicates an exceedance of the health protective level and indicates potential human health risk from the PFAS mixture in drinking water. Hazard Index = ([HFPO-DA water ng/l]/[10 ng/l]) + ([PFBS water ng/l]/[2000 ng/l]) + ([PFNA water ng/l]/[10 ng/l]) + ([PFHxS water ng/l]/[10 ng/l]) HBWC = health-based water concentration HQ = hazard quotient ng/l = nanograms per liter PFAS water = the concentration of a specific PFAS in water d)         USEPA, under section 1412 of SDWA identifies in Table 1 to subsection (d) the BAT, treatment technique, or other means available for achieving compliance with the maximum contaminant levels for all regulated PFAS identified in subsection (c). Table 1 to Subsection (d) BAT for PFAS Listed in Subsection (c)(2) CAS No. Contaminant BAT Not Applicable Hazard Index PFAS GAC, HPAE, RO, NF 122499-17-6 HFPO-DA GAC, HPAE, RO, NF 108427-53-8 PHFxS GAC, HPAE, RO, NF 72007-68-2 PFNA GAC, HPAE, RO, NF 45285-51-6 PFOA GAC, HPAE, RO, NF 45298-90-6 PFOS GAC, HPAE, RO, NF Abbreviations (BAT) GAC Granular Activated Carbon HPAE Anion Exchange NF Nanofiltration PTA Packed Tower Aeration RO Reverse Osmosis e)         USEPA, under section 1412 of SDWA, identifies in Table 1 to subsection (e) the affordable technology, treatment technique, or other means available to suppliers serving 10,000 persons or fewer for achieving compliance with the MCLs for all regulated PFAS identified in subsection (c)(2) Section 611.311(e) List of SSCTs for PFAS. Small System Compliance Technologies 1 Affordable for Listed Small System Categories 2 Anion Exchange All size categories. GAC All size categories. Reverse Osmosis, 3 Nanofiltration 3 3,301-10,000. 1 Section 1412(b)(4)(E)(ii) of SDWA specifies that small system compliance technologies (SSCTs) must be affordable and technically feasible for small systems. 2 SDWA specifies three categories of small systems: (i) those serving 25 or more, but fewer than 501, (ii) those serving more than 500, but fewer than 3,301, and (iii) those serving more than 3,300, but fewer than 10,001. 3 Technology rejects a large volume of water and may not be appropriate for areas where water quantity may be an issue. BOARD NOTE: This Section derives from 40 CFR 141.61.  More stringent state MCLs for 2,4-D, heptachlor, and heptachlor epoxide appear at Section 611.310.  In 40 CFR 141.6(g), USEPA postponed the effectiveness of the MCLs for aldicarb, aldicarb sulfone, and aldicarb sulfoxide until it took further action on those MCLs. See 40 CFR 141.6(g) and 57 Fed. Reg. 22178 (May 27, 1992).  USEPA later stated that it anticipated taking no action until 2005 on a federal national primary drinking water regulation (NPDWR) applicable to the aldicarbs. 68 Fed. Reg. 31108 (May 27, 2003).  In 2005, USEPA indicated no projected date for final action on the aldicarbs. See 70 Fed. Reg. 27501, 671 (May 16, 2005). An entry for the aldicarbs last appeared in USEPA's Spring 2007 semiannual regulatory agenda, indicating no projected dates for further action. See 72 Fed. Reg. 23156, 97 (Apr. 30, 2007); see also 72 Fed. Reg. 70118, 23 (Dec. 10, 2007) (the first USEPA regulatory agenda that included no entry for the aldicarbs).  As of early 2022, USEPA did not include the aldicarbs among the NPDWRs on its webpage.  USEPA, Ground Water and Drinking Water, National Primary Drinking Water Regulations (www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations; accessed February 16, 2022).  While the Board must maintain entries for aldicarb, aldicarb sulfoxide, and aldicarb sulfone to maintain consistency with the literal text of the federal rules ( see Sections 7.2 and 17.5 of the Act; 42 U.S.C. 300g-2; 40 CFR 142.10), the Board intends that no aldicarb requirements apply in Illinois until after USEPA adopts such requirements, and the Board removes this statement.