OAR 340-040-0090
Interim Standards for Maximum Measurable Levels of Contaminants in Groundwater to be Used in the Designation of a Groundwater Management Area

Interim standards are contained in Tables 4A, 5, and 6 of this division for maximum measurable levels (MMLs) of contaminants in groundwater to be used in the designation of a groundwater management area. Permanent standards for MMLs are found in Table 4B. The permanent or interim levels shall be used in all actions conducted by the Department where the use of maximum measurable levels for contaminants in groundwater is required.
Table 4A
INTERIM STANDARDS FOR MAXIMUM MEASURABLE LEVELS OF CONTAMINANTS IN GROUNDWATER :1, 2, 3
Inorganic Contaminants — Interim Standard (mg/L)
Arsenic — 0.05
Barium — 1.0
Cadmium — 0.010
Chromium — 0.05
Fluoride — 4.0
Lead — 0.05
Mercury — 0.002
Selenium — 0.01
Silver — 0.05
1All reference levels are for total (unfiltered) concentrations unless otherwise specified by the Department.
2The source of all standards listed is 40 CFR Part 141.
3MMLs are used to trigger designation of a groundwater management area when concentrations are detected on an area-wide basis which exceed 70 percent of the nitrate MML or 50 percent of other MMLs.
Table 4B
PERMANENT STANDARDS FOR MAXIMUM MEASURABLE LEVELS OF CONTAMINANTS IN GROUNDWATER (Continued): 1, 2, 3
Inorganic Contaminants —Standard (mg/L)
Nitrate-N — 10
(Nitrate expressed as Nitrogen)
1All reference levels are for total (unfiltered) concentrations unless otherwise specified by the Department.
2The source of all standards listed is 40 CFR Part 141.
3MMLs are used to trigger designation of a groundwater management area when concentrations are detected on an areawide basis which exceed 70 percent of the nitrate MML or 50 percent of other MMLs.
Table 5
INTERIM STANDARDS FOR MAXIMUM MEASURABLE LEVELS OF CONTAMINANTS IN GROUNDWATER (Continued): 1, 2, 3
Organic Contaminants — Interim Standard (mg/L)
Benzene — 0.005
Carbon Tetrachloride — 0.005
p-Dichlorobenzene — 0.075
1,2-Dichloroethane — 0.005
1,1-Dichloroethylene — 0.007
1,1,1-Trichloroethane — 0.20
Trichloroethylene — 0.005
Total Trihalomethanes — 0.10
(The sum of concentrations bromodichloromethane, dibromochloromethane, tribromomethane (bromoform), and trichloromethane (chloroform))
Vinyl Chloride — 0.002
2,4-D — 0.10
Endrin — 0.0002
Lindane — 0.004
Methoxychlor — 0.10
Toxaphene — 0.005
2,4,5-TP Silvex —0.01
1All reference levels are for total (unfiltered) concentrations unless otherwise specified by the Department.
2The source of all standards listed is 40 CFR Part 141.
3MMLs are used to trigger designation of a groundwater management area when concentrations are detected on an area-wide basis which exceed 70 percent of the nitrate MML or 50 percent of other MMLs.
Table 6
INTERIM STANDARDS FOR MAXIMUM MEASURABLE LEVELS OF CONTAMINANTS IN GROUNDWATER: 1, 3
Radioactive Substances, Microbiological and Turbidity
Contaminants — Interim Standard
Turbidity — 1 T U
Coliform Bacteria — < 1⁄100 ml
Radioactive Substances
Gross Alpha2 — 15 pCi/1
Combined Radium — 5 pCi/1
226 and 228
Gross Beta — 50 pCi/1
I - 131 — 3 pCi/1
Sr - 90 — 8 pCi/1
Tritium — 20,000 pCi/1
1The source of all standards listed is 40 CFR Part 141.
2Including Radium 225 but excluding Radon and Uranium.
3MMLs are used to trigger designation of a groundwater management area when concentrations are detected on an area-wide basis which exceed 70 percent of the nitrate MML or 50 percent of other MMLs.

Source: Rule 340-040-0090 — Interim Standards for Maximum Measurable Levels of Contaminants in Groundwater to be Used in the Designation of a Groundwater Management Area, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=340-040-0090.

340–040–0001
Preface 340–040–0010
Definitions 340–040–0020
General Policies 340–040–0030
Permitted Operations 340–040–0040
Remedial Investigation and Feasibility Study 340–040–0050
Selection of the Remedial Action 340–040–0060
Non-Permitted Activities 340–040–0070
On-Site Sewage Disposal: Area Wide Management 340–040–0080
Numerical Groundwater Quality Reference Levels and Guidance Levels 340–040–0090
Interim Standards for Maximum Measurable Levels of Contaminants in Groundwater to be Used in the Designation of a Groundwater Management Area 340–040–0100
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: Statement of Purpose 340–040–0105
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: Definitions 340–040–0108
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: General Policies 340–040–0110
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: Substances Regulated Under These Rules 340–040–0120
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: Notice of Intent to Propose Contaminants for Adoption of a Maximum Measurable Level 340–040–0125
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: Methods to Establish Maximum Measurable Levels 340–040–0130
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: Human Health and Environmental Advisories 340–040–0135
Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: Modification to the Maximum Measurable Level 340–040–0140
Wellhead Protection: Statement of Purpose 340–040–0150
Wellhead Protection: Definitions 340–040–0160
Wellhead Protection: General Policies 340–040–0170
Wellhead Protection: Required Elements of A Wellhead Protection Plan 340–040–0180
Wellhead Protection: Certification Procedure 340–040–0190
Wellhead Protection: Update Procedure 340–040–0200
Wellhead Protection: Decertification Procedure 340–040–0210
Wellhead Protection: Appeal Procedure
Last Updated

Jun. 8, 2021

Rule 340-040-0090’s source at or​.us