Authority: IC 13-18

Affected: IC 4-22-2; IC 13-14-9; IC 13-18-4; IC 13-18-17

Sec. 6. (a) The following numeric criteria are health protective goals for untreated ground water used as drinking water and are the maximum permissible level of a contaminant in drinking water class ground water:

1. (1) The following are the numeric criteria for select inorganic contaminants:

   Contaminant	Criterion (mg/l unless noted)1
   Antimony	0.006
   Arsenic	0.010
   Asbestos	7 MFL2
   Barium	2
   Beryllium	0.004
   Cadmium	0.005
   Chromium (total)	0.1
   Combined beta/photon emitters	4 mrem/yr3
   Cyanide (free)	0.2
   Fluoride	4
   Gross alpha particle activity (including radium 226 but excluding radon and uranium)	15 pCi/L4
   Lead	0.015
   Mercury (inorganic)	0.002
   Nitrate (as N)	10
   Nitrite (as N)	1
   Radium 226 and 228 (combined)	5 pCi/L
   Selenium	0.05
   Thallium	0.002
   Notes:
   1mg/l is milligrams per liter.
   2MFL is million fibers per liter greater than 10 micrometers in length.
   3mrem/yr is millirems per year.
   4pCi/L is picocuries per liter.

2. (2) The following are the numeric criteria for select organic contaminants:

   Table 6(a)(2)
   Numeric Criteria for Organic Contaminants in Drinking Water Class Ground Water
   Chemical Abstract Registry Numbers	Contaminant	Criterion (mg/l unless noted)
   15972-60-8	Alachlor	0.002
   1912-24-9	Atrazine	0.003
   71-43-2	Benzene	0.005
   50-32-8	Benzo(a)pyrene	0.0002
   1563-66-2	Carbofuran	0.04
   56-23-5	Carbon tetrachloride	0.005
   57-74-9	Chlordane	0.002
   94-75-7	2,4-D	0.07
   75-99-0	Dalapon	0.2
   103-23-1	Di(2-ethylhexyl)adipate	0.4
   96-12-8	Dibromochloropropane (DBCP)	0.0002
   95-50-1	Dichlorobenzene, 1,2-	0.6
   106-46-7	Dichlorobenzene, 1,4-	0.075
   107-06-2	Dichloroethane, 1,2-	0.005
   75-35-4	Dichloroethylene, 1,1-	0.007
   156-59-2	Dichloroethylene, cis-1,2-	0.07
   156-60-5	Dichloroethylene, trans-1,2-	0.1
   75-09-2	Dichloromethane or methylene chloride	0.005
   78-87-5	Dichloropropane, 1,2-	0.005
   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
   100-41-4	Ethylbenzene	0.7
   106-93-4	Ethylene dibromide (EDB)	0.00005
   1071-83-6	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 (gamma-BHC)	0.0002
   72-43-5	Methoxychlor	0.04
   108-90-7	Monochlorobenzene	0.1
   23135-22-0	Oxamyl (vydate)	0.2
   87-89-5	Pentachlorophenol	0.001
   1918-02-1	Picloram	0.5
   1336-36-3	Polychlorinated biphenyls (PCBs)	0.0005
   122-34-9	Simazine	0.004
   100-42-5	Styrene	0.1
   1746-01-6	2,3,7,8-TCDD (Dioxin)	0.00000003
   127-18-4	Tetrachloroethylene	0.005
   108-88-3	Toluene	1
   8001-35-2	Toxaphene	0.003
   93-72-1	2,4,5-TP (Silvex)	0.05
   120-82-1	Trichlorobenzene, 1,2,4-	0.07
   71-55-6	Trichloroethane, 1,1,1-	0.2
   79-00-5	Trichloroethane, 1,1,2-	0.005
   79-01-6	Trichloroethylene	0.005
   75-01-4	Vinyl chloride	0.002
   1330-20-7	Xylenes (total)	10

3. (3) A drinking water class numeric criterion may be added to the criteria established in this subsection if adopted according to IC 4-22-2 and IC 13-14-9.

(b) An agency shall determine if further action is necessary to comply with the narrative criteria established in section 5 of this rule if the following indicator levels are exceeded in drinking water class ground water:

1. (1) Chloride at two hundred fifty (250) milligrams per liter.
2. (2) Sulfate at two hundred fifty (250) milligrams per liter.
3. (3) Total dissolved solids at five hundred (500) milligrams per liter.
4. (4) Total coliform bacteria at nondetect.

(c) If the commissioner determines that a site-specific numeric criterion for a contaminant without a drinking water class numeric criterion established in subsection (a) is necessary to protect human health, any natural resource, or the environment, a risk analysis shall be used to establish a numeric criterion for that contaminant and must:

1. (1) receive approval from the commissioner; and
2. (2) be based upon appropriate toxicological data.

(d) The naturally occurring concentration of a contaminant in drinking water class ground water shall be the numeric criterion if that contaminant occurs at a concentration greater than the drinking water numeric criterion established in subsection (a) or (c) or an indicator level established in subsection (b).

(e) If drinking water class ground water at a facility, practice, or activity is determined to have one (1) or more contaminant concentrations above the numeric criteria established in this section that are not attributable to the facility, practice, or activity under consideration, an agency shall manage the facility, practice, or activity or implement programs such that:

1. (1) the facility, practice, or activity causes no further increase in the concentration of the contaminant determined to be above the numeric criterion established in this section; and
2. (2) any design standard or management requirements that apply to the facility, practice, or activity are at least as stringent as the design standard and management requirements that would be applied to a facility, practice, or activity where ground water does not have one (1) or more contaminant concentrations above the numeric criteria established in this section.

(f) The commissioner may, for a ground water contamination assessment or remediation at a facility, practice, or activity under the jurisdiction of the department of environmental management, allow an appropriate site-specific, risk-based numeric criterion different from the numeric criterion established in subsection (a) or (d) to be applied to drinking water class ground water within the boundary of the ground water management zone established according to section 9 of this rule.

(Water Pollution Control Division; 327 IAC 2-11-6; filed Feb 4, 2002, 11:00 a.m.: 25 IR 1879; readopted filed Jun 4, 2008, 11:07 a.m.: 20080702-IR-327080207BFA; filed Nov 24, 2008, 12:30 p.m.: 20081217-IR-327060280FRA; readopted filed Jul 30, 2014, 4:04 p.m.: 20140827-IR-327140189BFA; readopted filed May 27, 2020, 11:52 a.m.: 20200624-IR-327200186BFA; readopted filed Oct 18, 2024, 1:57 p.m.: 20241113-IR-327230810RFA)