AttachmentA_15A-NCAC-02L-0202_ProposedAmendedRuleText

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15A NCAC 02L .0202 is proposed for amendment as follows: 1
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15A NCAC 02L .0202 GROUNDWATER QUALITY STANDARDS 3
(a) The groundwater quality standards for the protection of the groundwaters of the State are those specified in this4
Rule. They are the maximum allowable concentrations resulting from any discharge of contaminants to the land or 5
waters of the State, which may be tolerated without creating a threat to human health or which would otherwise render 6
the groundwater unsuitable for its intended best usage. 7
(b) The groundwater quality standards for contaminants specified in Paragraphs (h) and (i) of this Rule are as listed,8
except that: 9
(1)Where the standard for a substance is less than the practical quantitation limit, the detection of that10
substance at or above the practical quantitation limit constitutes a violation of the standard. The11
practical quantitation limit, defined in Rule .0102 of this Subchapter, is a scientific standard pursuant 12
to G.S. 150B-2(8a)(h).13
(2)Where two or more substances exist in combination, the Director shall consider the effects of14
chemical interactions after consulting with the Division of Public Health and may establish15
maximum concentrations at values less than those established in accordance with Paragraphs (c),16
(h), or (i) of this Rule, based on additive toxic effects. In the absence of information to the contrary,17
in accordance with Paragraph (d) of this Rule, the carcinogenic risks associated with carcinogens18
present shall be considered additive and the toxic effects associated with non-carcinogens present19
shall also be considered additive.20
(3)Where naturally occurring substances exceed the established standard, the standard shall be the21
naturally occurring concentration as established by the Director based upon site-specific conditions.22
(4)Where the groundwater standard for a substance is greater than the Maximum Contaminant Level23
(MCL), the Director shall apply the MCL as the groundwater standard at any private drinking water24
well or public water system well that may be impacted.25
(c) Except for tracers, the use of which has been permitted by the Division in 15A NCAC 02C .0200, substances that26
are not naturally occurring and for which no standard is specified in Paragraphs (h) or (i) of this Rule shall not be 27
permitted in concentrations at or above the practical quantitation limit in Class GA or Class GSA groundwaters. Any 28
person may request the Director of the Division of Water Resources modify this requirement by establishing an Interim 29
Maximum Allowable Concentration (IMAC) in accordance with the specific guidelines listed in Subparagraphs (1)-30
(9) of this Paragraph. In addition, any person may request the Director of the Division of Water Resources to update31
or remove an existing IMAC in accordance with the specific guidelines listed in Subparagraphs (1)-(9) of this 32
Paragraph. The requestor shall submit relevant toxicological and epidemiological data, study results, and calculations 33
in accordance with Paragraphs (d) and (e) of this Rule. The specific guidelines are as follows: 34
(1)The Division shall review the request to determine whether the information submitted is in35
accordance with Paragraphs (d) and (e) of this Rule.36
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(2) If the information submitted is not in accordance with Paragraphs (d) and (e) of this Rule, the 1
Director of the Division of Water Resources shall request additional information from the requester. 2
If the requester does not provide the additional information necessary to be in accordance with 3
Paragraphs (d) and (e) of this Rule, the Director of the Division of Water Resources shall return the 4
request. 5
(3) If the information submitted is in accordance with Paragraphs (d) and (e) of this Rule, at least 30 6
days prior to establishing, updating, or removing an IMAC for any substance, the Division of Water 7
Resources shall provide public notice and opportunity for comment that an IMAC has been 8
requested to be established, updated, or removed. The public notice shall include: 9
(A) the request for the establishment, update, or removal of the IMAC for a substance, 10
(B) the level of the proposed IMAC, which is calculated by the Division of Water Resources 11
in accordance with Paragraphs (d) and (e) of this Rule, 12
(C) if applicable the level of the existing IMAC, and 13
(D) the basis upon which the Division of Water Resources has relied in development of the 14
proposed IMAC establishment, update, or removal. 15
This notice shall be emailed to interested parties and posted on the Division of Water Resources' 16
website: https://deq.nc.gov/about/divisions/water-resources/water-planning/classification-17
standards/groundwater-imacs. 18
(4) If the Director of the Division of Water Resources finds the establishment, update or removal will 19
not degrade the quality of the groundwaters, will not likely cause or contribute to pollution of the 20
waters of the state, and will be protective of public health, then the Director shall establish, update 21
or remove the IMAC. If the request does not meet the requirements listed in this Subparagraph, the 22
Director of the Division of Water Resources shall return the request. The Director shall establish, 23
update, or remove the IMAC or return the request within 180 calendar days of receipt of a request 24
submitted in accordance with Paragraphs (d) and (e) of this Rule unless the requester agrees, in 25
writing, to a longer period. Failure by the Director to establish, update or remove an IMAC or return 26
the request within 180 days of receipt of a request submitted in accordance with Paragraphs (d) and 27
(e) of this Rule shall be considered a return of the request. 28
(5) If the Director of the Division of Water Resources establishes or updates an IMAC, the IMAC shall 29
be posted on the Division of Water Resource's website and the Commission shall be notified in 30
writing within 30 calendar days and at the next regularly scheduled Commission meeting that a new 31
IMAC has been established or an existing IMAC has been updated or removed. 32
(6) (A) Within 12 months of establishing an IMAC pursuant to this Paragraph, the Director of the 33
Division of Water Resources shall make a recommendation to the Commission whether: 34
(i) a new groundwater standard in place of the IMAC should be established pursuant 35
to this Rule; or 36
(ii) the IMAC should expire. 37
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(B) After a recommendation is presented by the Director under Part (A) of this Subparagraph, 1
the Commission shall decide whether rulemaking shall be initiated to adopt a new 2
groundwater standard in place of the IMAC. 3
(C) If the Commission initiates rulemaking to adopt a new groundwater standard in place of 4
the IMAC, then the IMAC shall remain in effect unless it expires under Subparagraph (7) 5
of this Paragraph. 6
(7) An IMAC shall expire upon the earliest of: 7
(A) the date the Commission declines to initiate rulemaking to adopt a new groundwater 8
standard in place of the IMAC under Part (B) of Subparagraph (c)(6); 9
(B) the effective date of a Rule adopted by the Commission establishing a new groundwater 10
standard in place of the IMAC; or 11
(C) after initiating rulemaking pursuant to Part (C) of Subparagraph (c)(6), the date the 12
Commission declines to adopt a new groundwater standard in place of the IMAC. 13
(8) For any IMAC that expires prior to the adoption by the Commission of a new groundwater standard 14
in place of the IMAC, any person may request an IMAC be established again under this Paragraph 15
based on new information in accordance with Paragraphs (d) and (e) of this Rule that was not 16
included in the original IMAC request to the Director or new site information that was not included 17
in the original IMAC request to the Director. 18
(9) The Director of the Division of Water Resources shall provide an annual update to the Commission 19
on the status of pending IMAC requests and any IMACs that have been established, updated or 20
removed during the previous calendar year. 21
(d) Except as provided in Paragraph (f) of this Rule, groundwater quality standards for substances in Class GA and 22
Class GSA groundwaters are established as the least of: 23
(1) Systemic threshold concentration calculated as follows: [Reference Dose (mg/kg/day) x 70 kg (adult 24
body weight) x Relative Source Contribution (0.10 for inorganics; 0.20 for organics)] / [2 liters/day 25
(avg. water consumption)]; 26
(2) Concentration that corresponds to an incremental lifetime cancer risk of 1x10-6; 27
(3) Taste threshold limit value; 28
(4) Odor threshold limit value; 29
(5) Maximum contaminant level; or 30
(6) National secondary drinking water standard. 31
(e) The following references, in order of preference, shall be used in establishing concentrations of substances which 32
correspond to levels described in Paragraph (d) of this Rule: 33
(1) Integrated Risk Information System (U.S. EPA); 34
(2) Health Advisories (U.S. EPA Office of Drinking Water); 35
(3) Other health risk assessment data published by the U.S. EPA; or 36
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(4) Other relevant, published health risk assessment data, and scientifically valid peer-reviewed 1
published toxicological data. 2
(f) The Commission may establish groundwater standards less stringent than existing maximum contaminant levels 3
or national secondary drinking water standards if it finds, after public notice and opportunity for hearing in accordance 4
with G.S. 150B, that: 5
(1) more recent data published in the EPA health references listed in Paragraph (e) of this Rule results 6
in a standard that is protective of public health, taste threshold, or odor threshold; 7
(2) the standard will not endanger the public health and safety, including health and environmental 8
effects from exposure to groundwater contaminants; and 9
(3) compliance with a standard based on the maximum contaminant level or national secondary drinking 10
water standard would produce substantial hardship without equal or greater public benefit. 11
(g) Groundwater quality standards specified in Paragraphs (h) and (i) of this Rule shall be reviewed by the Division 12
of Water Resources on a triennial basis to consider whether to recommend to the Commission that new or revised 13
groundwater quality standards be adopted in accordance with Paragraphs (d) and (e) of this Rule. 14
(h) Class GA Standards. Unless otherwise indicated, the standard refers to the total concentration in micrograms per 15
liter (µg/L) of any constituent in a dissolved, colloidal, or particulate form that is mobile in groundwater. These 16
standards do not apply to sediment or other particulate matter that is preserved in a groundwater sample as a result of 17
well construction or sampling procedures. The Class GA standards are: 18
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Substance Chemical Abstracts
Service (CAS) Registry
Number
Standard (µg/L) (µg/L
unless otherwise indicated)
Acenaphthene 83-32-9 80
Acenaphthylene 208-96-8 200
Acetic acid 64-19-7 5,000
Acetochlor 34256-82-1 100
Acetochlor ESA 187022-11-3 500
Acetochlor OXA 184992-44-4 500
Acetone 67-64-1 6,000
Acetophenone 98-86-2 700
Acrolein 107-02-8 4
Acrylamide 79-06-1 0.008
Alachlor 15972-60-8 2
Aldrin 309-00-2 0.002
Anthracene 120-12-7 2,000
Antimony 7440-36-0 1
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Arsenic 7440-38-2 10
Atrazine and chlorotriazine metabolites 1912-24-9 3
Barium 7440-39-3 700
Benzene 71-43-2 1
Benzo(a)anthracene 56-55-3 0.05
Benzo(a)pyrene 50-32-8 0.005
Benzo(b)fluoranthene 205-99-2 0.05
Benzo(g,h,i)perylene 191-24-2 200
Benzo(k)fluoranthene 207-08-9 0.5
Benzoic acid 65-85-0 30,000
Benzyl alcohol 100-51-6 700
Beryllium 7440-41-7 4
Bis(chloroethyl)ether 111-44-4 0.03
Bis(2-ethylhexyl) phthalate 117-81-7 3
Boron 7440-42-8 700
Bromodichloromethane 75-27-4 0.6
Bromoform 75-25-2 4
Bromomethane 74-83-9 10
n-Butanol 71-36-3 590
sec-Butanol 78-92-2 10,000
n-Butylbenzene 104-51-8 70
sec-Butylbenzene 135-98-8 70
tert-Butylbenzene 98-06-6 70
Butylbenzyl phthalate 85-68-7 1,000
Cadmium 7440-43-9 2
Caprolactam 105-60-2 4,000
Carbofuran 1563-66-2 40
Carbon disulfide 75-15-0 700
Carbon tetrachloride 56-23-5 0.3
Chlordane 12789-03-6 0.1
Chloride 16887-00-6 250,000
Chlorobenzene 108-90-7 50
Chloroethane 75-00-3 3,000
Chloroform 67-66-3 70
Chloromethane 74-87-3 3
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2-Chlorophenol 95-57-8 0.4
2-Chlorotoluene 95-49-8 100
4-Chlorotoluene 106-43-4 24
Chromium 7440-47-3 10
Chrysene 218-01-9 5
Cobalt 7440-48-4 1
Coliform organisms (total) No CAS Registry Number 1 per 100 mL
Color No CAS Registry Number 15 color units
Copper 7440-50-8 1,000
Cyanide (free cyanide) 57-12-5 70
2,4-D (2,4-dichlorophenoxy acetic acid) 94-75-7 70
Dalapon 75-99-0 200
DDD 72-54-8 0.1
DDE 72-55-9 0.1
DDT 50-29-3 0.1
Dibenz(a,h)anthracene 53-70-3 0.005
1,4-Dibromobenzene 106-37-6 70
Dibromochloromethane 124-48-1 0.4
1,2-Dibromo-3-chloropropane 96-12-8 0.04
Dibutyl phthalate 84-74-2 700
Dichloroacetic acid 79-43-6 0.7
1,2-Dichlorobenzene 95-50-1 20
1,3-Dichlorobenzene 541-73-1 200
1,4-Dichlorobenzene 106-46-7 6
Dichlorodifluoromethane 75-71-8 1,000
1,1-Dichloroethane 75-34-3 6
1,2-Dichloroethane 107-06-2 0.4
1,2-Dichloroethene (cis) 156-59-2 70
1,2-Dichloroethene (trans) 156-60-5 100
1,1-Dichloroethylene 75-35-4 350
2,4-Dichlorophenol 120-83-2 0.98
1,2-Dichloropropane 78-87-5 0.6
1,3-Dichloropropene (cis and trans isomers) 542-75-6 0.4
Dieldrin 60-57-1 0.002
Diethylphthalate 84-66-2 6,000
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2,4-Dimethylphenol 105-67-9 100
2,4-Dinitrotoluene 121-14-2 0.05
2,6-Dinitrotoluene 606-20-2 0.05
Di-n-octyl phthalate 117-84-0 100
Dinoseb 88-85-7 7
1,4-Dioxane 123-91-1 3
Dioxin (2,3,7,8-TCDD) 1746-01-6 0.0002 ng/L
1,1-Diphenyl 92-52-4 400
Diphenyl ether 101-84-8 180
Diquat 85-00-7 20
Dissolved solids (total) No CAS Registry Number 500,000
Disulfoton 298-04-4 0.3
Diundecyl phthalate (Santicizer 711) 3648-20-2 100
Endosulfan 115-29-7 40
Endosulfan sulfate 1031-07-8 40
Endothall 145-73-3 100
Endrin, total (includes endrin, endrin aldehyde, and
endrin ketone) 72-20-8 2
Epichlorohydrin 106-89-8 4
Ethyl acetate 141-78-6 3,000
Ethylbenzene 100-41-4 600
Ethylene dibromide 106-93-4 0.02
Ethylene glycol 107-21-1 10,000
Fluoranthene 206-44-0 300
Fluorene 86-73-7 300
Fluoride 16984-48-8 2,000
Foaming agents No CAS Registry Number 500
Formaldehyde 50-00-0 600
Gross alpha (adjusted) particle activity (excludes radium-226 and uranium) 12587-46-1 15 pCi/L
Heptachlor 76-44-8 0.008
Heptachlor epoxide 1024-57-3 0.004
Heptane 142-82-5 400
Hexachlorobenzene 118-74-1 0.02
Hexachlorobutadiene 87-68-3 0.4
Hexachlorocyclohexane isomers (technical grade) 608-73-1 0.02
alpha-Hexachlorocyclohexane 319-84-6 0.006
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beta-Hexachlorocyclohexane 319-85-7 0.02
gamma-Hexachlorocyclohexane (Lindane) 58-89-9 0.03
Hexafluoropropylene oxide dimer acid (HFPO-DA) 13252-13-6 0.01
n-Hexane 110-54-3 400
Indeno(1,2,3-cd)pyrene 193-39-5 0.05
Iron 7439-89-6 300
Isophorone 78-59-1 40
Isopropyl ether 108-20-3 70
Isopropylbenzene 98-82-8 70
4-Isopropyltoluene 99-87-6 25
Lead 7439-92-1 15
Manganese 7439-96-5 50
Mercury 7439-97-6 1
Methanol 67-56-1 4,000
Methoxychlor 72-43-5 40
Methylene chloride 75-09-2 5
Methyl butyl ketone 591-78-6 40
Methyl ethyl ketone 78-93-3 4,000
Methyl isobutyl ketone 108-10-1 100
Methyl methacrylate 80-62-6 25
1-Methylnapthalene 90-12-0 1
2-Methylnaphthalene 91-57-6 30
2-Methylphenol 95-48-7 400
3-Methylphenol 108-39-4 400
4-Methylphenol 106-44-5 40
Methyl tert-butyl ether (MTBE) 1634-04-4 20
Naphthalene 91-20-3 6
Nickel 7440-02-0 100
Nitrate (as N) 14797-55-8 10,000
Nitrite (as N) 14797-65-0 1,000
N-nitrosodimethylamine 62-75-9 0.0007
Oxamyl 23135-22-0 200
Pentachlorophenol 87-86-5 0.3
Petroleum aliphatic carbon fraction class (C5 – C8) No CAS Registry Number 400
Perfluorobutane sulfonic acid (PFBS) 375-73-5 2
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Perfluorobutanoic acid (PFBA) 375-22-4 7
Perfluorohexane sulfonic acid (PFHxS) 355-46-4 0.01
Perfluorohexanoic acid (PFHxA) 307-24-4 4
Perfluorononanoic acid (PFNA) 375-95-1 0.01
Perfluorooctanoic acid (PFOA) 335-67-1 0.001 ng/L
Perfluorooctane sulfonic acid (PFOS) 1763-23-1 0.7 ng/L
Petroleum aliphatic carbon fraction class (C9 – C18) No CAS Registry Number 700
Petroleum aliphatic carbon fraction class (C19 – C36) No CAS Registry Number 10,000
Petroleum aromatics carbon fraction class (C9 – C22) No CAS Registry Number 200
pH No CAS Registry Number 6.5 - 8.5 (no unit)
Phenanthrene 85-01-8 200
Phenol 108-95-2 30
Phorate 298-02-2 1
n-Propylbenzene 103-65-1 70
Propylene glycol 57-55-6 100,000
Pyrene 129-00-0 200
Selenium 7782-49-2 20
Silver 7440-22-4 20
Simazine 122-34-9 4
Strontium 7440-24-6 2,000
Styrene 100-42-5 70
Sulfate 14808-79-8 250,000
1,2,4,5-Tetrachlorobenzene 95-94-3 2
1,1,2,2-Tetrachloroethane 79-34-5 0.2
1,1,1,2-Tetrachloroethane 630-20-6 1
Tetrachloroethylene (PCE) 127-18-4 0.7
2,3,4,6-Tetrachlorophenol 58-90-2 200
Thallium 7440-28-0 2
Tin (inorganic forms) 7440-31-5 2,000
Toluene 108-88-3 600
Toxaphene 8001-35-2 0.03
2,4,5-TP (Silvex) 93-72-1 50
1,2,4-Trichlorobenzene 120-82-1 70
1,1,1-Trichloroethane 71-55-6 200
1,1,2-Trichloroethane 79-00-5 0.6
Trichloroethylene (TCE) 79-01-6 3
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Trichlorofluoromethane 75-69-4 2,000
2,4,5-Trichlorophenol 95-95-4 63
2,4,6-Trichlorophenol 88-06-2 4
1,2,3-Trichloropropane 96-18-4 0.005
1,2,4-Trimethylbenzene 95-63-6 400
1,3,5-Trimethylbenzene 108-67-8 400
Vanadium 7440-62-2 7
1,1,2-Trichloro-1,2,2-trifluoroethane 76-13-1 200,000
Vinyl chloride 75-01-4 0.03
Xylenes 1330-20-7 500
Zinc 7440-66-6 1,000
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(i) Class GSA Standards. The standards for this class are the same as those for Class GA except as follows: 2
(1) chloride: allowable increase not to exceed 100 percent of the natural quality concentration; and 3
(2) dissolved solids (total): 1,000,000 µg/L. 4
(j) Class GC Standards. 5
(1) The concentrations of substances that, at the time of classification, exceed the standards applicable 6
to Class GA or GSA groundwaters shall not be caused to increase, nor shall the concentrations of 7
other substances be caused to exceed the GA or GSA standards as a result of further disposal of 8
contaminants to or beneath the surface of the land within the boundary of the area classified GC. 9
(2) The concentrations of substances that, at the time of classification, exceed the standards applicable 10
to GA or GSA groundwaters shall not be caused to migrate as a result of activities within the 11
boundary of the GC classification, so as to violate the groundwater or surface water quality standards 12
in adjoining waters of a different class. 13
(3) Concentrations of specific substances, that exceed the established standard at the time of 14
classification, are listed in Section .0300 of this Subchapter. 15
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History Note: Authority G.S. 143-214.1; 143-214.2; 143-215.3(a)(1); 143-215.3(a)(4); 143B-282(a)(2); 150B-17
2(8a)(h); 150B-19(6); 18
Eff. June 10, 1979; 19
Amended Eff. November 1, 1994; October 1, 1993; September 1, 1992; August 1, 1989; 20
Temporary Amendment Eff. June 30, 2002; 21
Amended Eff. August 1, 2002; 22
Temporary Amendment Expired February 9, 2003; 23
Amended Eff. April 1, 2013; January 1, 2010; April 1, 2005; 24
Pursuant to G.S. 150B-21.3A, rule is necessary without substantive public interest Eff. March 6, 25
2018; 26
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Amended Eff. April 1, 2022.2022; 1
Amended Eff. [Date TBD]. 2
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