AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing changes to its test procedures required to be used by industries and municipalities when analyzing the chemical, physical, and biological properties of wastewater and other environmental samples for reporting under the EPA's National Pollutant Discharge Elimination System (NPDES) permit program. The Clean Water Act requires the EPA to promulgate these test procedures (analytical methods) for analysis of pollutants. The EPA anticipates that these proposed changes will provide increased flexibility for the regulated community in meeting monitoring requirements while improving data quality. In addition, this proposed update to the CWA methods would incorporate technological advances in analytical technology. As such, the EPA expects that there will be no negative economic impacts resulting from these proposed changes.

DATES:

Comments on this proposed rule must be received on or before December 23, 2019.

ADDRESSES:

You may send comments, identified by Docket ID No. EPA-HQ-OW-2018-0826, by any of the following means:

• Federal eRulemaking Portal: https://www.regulations.gov/​_ (preferred way of receiving comments): Follow the online instructions for submitting comments.
• Email: OW-Docket@epa.gov. Include Docket ID No. EPA-HQ-OW-2018-0826 in the subject line of the message.
• Mail: U.S. Environmental Protection Agency, EPA Docket Center, Office of Water Docket, Mail Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460.
• Hand Delivery/Courier: EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. The Docket Center's hours of operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal Holidays).

Instructions: All submissions received must include the Docket ID No. for this rulemaking. Comments received may be posted without change to https://www.regulations.gov/​, including any personal information provided. For detailed instructions on sending comments and additional information on the rulemaking process, see Section I.B “What Should I Consider as I Prepare My Comments for the EPA” heading of the SUPPLEMENTARY INFORMATION section of this document.

Docket: All documents in the docket are listed in the www.regulations.gov index. Although listed in the index, some information in the docket is not publicly available, e.g., Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in www.regulations.gov or in hard copy at the Water Docket in EPA Docket Center, EPA/DC, EPA West William J. Clinton Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is 202-566-1744, and the telephone number for the Water Docket is 202-566-2426.

FOR FURTHER INFORMATION CONTACT:

Meghan Hessenauer, Engineering and Analysis Division (4303T), Office of Water, Environmental Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460-0001; telephone: 202-566-1040; email: Hessenauer.Meghan@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information

A. Does this action apply to me?

Entities potentially affected by the requirements of this proposed action include:

This table is not exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. This table lists types of entities that the EPA is now aware of that could potentially be affected by this action. Other types of entities not listed in the table could also be affected. To determine whether your facility is affected by this action, you should carefully examine the applicability language at 40 CFR 122.1 (NPDES purpose and scope), 40 CFR 136.1 (NPDES permits and CWA) and 40 CFR 403.1 (pretreatment standards purpose and applicability). If you have questions regarding the applicability of this action to a particular entity, consult the appropriate person listed in the preceding FOR FURTHER INFORMATION CONTACT section.

B. What should I consider as I prepare my comments for the EPA?

Submit your comments, identified by Docket ID No. EPA-HQ-OW-2018-0826, at https://www.regulations.gov (preferred way of receiving comments), or the other means identified in the ADDRESSES section. Once submitted, comments cannot be edited or removed from the docket. The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be CBI or other information whose disclosure is restricted by statute. Do not submit CBI to the EPA through www.regulations.gov or email. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk that you mail to the EPA, mark the outside of the disk as CBI and then identify electronically within the disk the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures for handling and protection of CBI set forth in 40 CFR part 2.

Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission means or methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/​dockets/​commenting-epa-dockets.

II. Overview

This preamble describes the reasons for the proposed rule; the legal authority for the proposed rule; a summary of the proposed changes and clarifications; and explanation of the abbreviations and acronyms used in this document. In addition, this preamble solicits comment and data from the public.

Abbreviations and Acronyms Used in the Preamble and Proposed Rule Text

2-CEVE: 2-Chloroethylvinyl ether

AA: Atomic Absorption

ADMI: American Dye Manufacturers Institute

ASTM: ASTM International ^[1]

ATP: Alternate Test Procedure

BHI: Brain heart infusion

BOD₅: 5-day Biochemical Oxygen Demand

CAS: Chemical Abstract Services

CATC: Cyanide Amenable to Chlorination

CCB: Continuing calibration blank

CCV: Continuing calibration verification

CFR: Code of Federal Regulations

COD: Chemical Oxygen Demand

CWA: Clean Water Act

EC-MUG: EC broth with 4-methylumbelliferyl-β-D-glucuronide

EDTA: Ethylenediaminetetraacetic acid

ELAB: Environmental Laboratory Advisory Board

EPA: Environmental Protection Agency

FLAA: Flame Atomic Absorption Spectroscopy

GC: Gas Chromatography

GFAA: Graphite Furnace Atomic Absorption Spectroscopy

ICP/AES: Inductively Coupled Plasma-Atomic Emission Spectroscopy

ICP/MS: Inductively Coupled Plasma-Mass Spectrometry

ILI: Independent Laboratories Institute

IPR: Initial Precision and Recovery

LCS: Laboratory Control Sample

MDL: Method Detection Limit

MF: Membrane Filtration

MgCl₂: Magnesium Chloride

MPN: Most Probable Number

MS/MSD: Matrix Spike/Matrix Spike Duplicate

MS: Mass Spectrometry

NA-MUG: Nutrient Agar with 4-methylumbelliferyl-β-D-glucuronide

NECi: A shortened name used by the Nitrate Elimination Company, Inc.

NPDES: National Pollutant Discharge Elimination System

NTTAA: National Technology Transfer and Advancement Act

OPR: Ongoing Precision and Recovery

QC: Quality Control

STGFAA: Stabilized Temperature Graphite Furnace Atomic Absorption Spectroscopy

TKN: Total Kjeldahl Nitrogen

TOC: Total Organic Carbon

USGS: United States Geological Survey

VCSB: Voluntary Consensus Standards Body

III. Statutory Authority

The EPA is proposing this regulation under the authorities of sections 301(a), 304(h), and 501(a) of the CWA; 33 U.S.C. 1311(a), 1314(h), and 1361(a). Section 301(a) of the CWA prohibits the discharge of any pollutant into navigable waters unless the discharge complies with, among other provisions, an NPDES permit issued under section 402 of the CWA. Section 304(h) of the CWA requires the Administrator of the EPA to “. . . promulgate guidelines establishing test procedures for the analysis of pollutants that shall include the factors which must be provided in any certification pursuant to [section 401 of the CWA] or permit application pursuant to [section 402 of the CWA].” Section 501(a) of the CWA authorizes the Administrator to “. . . prescribe such regulations as are necessary to carry out this function under [the CWA].” The EPA generally has codified its test procedure regulations (including analysis and sampling requirements) for CWA programs at 40 CFR part 136, though some requirements are codified in other parts (e.g., 40 CFR Chapter I, Subchapters N and O).

IV. Purpose and Summary of Proposed Rule

NPDES permits must include conditions designed to ensure compliance with the technology-based and water quality-based requirements of the CWA, including in many cases, restrictions on the quantity of specific pollutants that can be discharged as well as pollutant measurement and reporting requirements. Often, entities have a choice in deciding which approved test procedure they will use for a specific pollutant because the EPA has approved the use of more than one method.^[2]

The procedures for the analysis of pollutants required by CWA section 304(h) are a central element of the NPDES permit program. Examples of where these EPA-approved analytical methods must be used include the following: (1) Applications for NPDES permits, (2) sampling or other reports required under NPDES permits, (3) other requests for quantitative or qualitative effluent data under the NPDES regulations, (4) State CWA 401 certifications and (5) sampling and analysis required under the EPA's General Pretreatment Regulations for Existing and New Sources of Pollution, 40 CFR 136.1 and 40 CFR 403.12(b)(5)(v).

Periodically, the EPA proposes to update the approved methods in 40 CFR part 136. In general, the changes proposed in this action fall into the following categories. The first is new or revised methods published by the VCSBs or the USGS that are similar to methods previously adopted as EPA-approved methods in 40 CFR part 136. The second category is methods the EPA has reviewed under the Agency's national ATP program and preliminarily concluded are appropriate for nationwide use. Finally, the EPA is proposing certain corrections or amendments to the text and tables of 40 CFR part 136. The EPA is proposing adoption of these revisions to improve data quality, update methods to keep current with technology advances, and provide the regulated community with greater flexibility. The following paragraphs provide details on the proposed revisions.

A. Changes to 40 CFR 136.3 To Include New Versions of Previously Approved EPA Methods

The EPA proposes to add the latest version of EPA Method 1623 to Table IH. The latest version of Method 1623 (labeled 1623.1) includes updated acceptance criteria for IPR, OPR, and MS/MSD, and clarifications and revisions based on user questions and feedback about Method 1623 over the past 19 years.

B. Methods Incorporated by Reference

Currently, hundreds of methods and ATPs are incorporated by reference within 40 CFR part 136. In most cases, 40 CFR part 136 contains multiple approved methods for a single pollutant, and regulated entities often have a choice in selecting a method. The proposed rule contains revisions to VCSB methods that are currently incorporated by reference. Two VCSBs have made such revisions, Standard Methods and ASTM. The proposed VCSB methods are consistent with the requirements of the National Technology Transfer and Advancement Act (NTTAA), under which federal agencies use technical standards developed or adopted by the VCSBs if compliance would not be inconsistent with applicable law or otherwise impracticable (see Section V.I below). The proposed VCSB methods are available on their respective websites (www.standardmethods.org/​ and www.astm.org) to everyone at a cost determined by the VCSB, generally from $40 to $80. Both organizations also offer memberships or subscriptions that allow unlimited access to their methods. The cost of obtaining these methods is not a significant financial burden for a discharger or environmental laboratory, making the methods reasonably available. Finally, this proposal also includes USGS methods and vendor ATPs, all of which the EPA proposes to incorporate by reference. The ATPs and USGS methods are available free of charge on their respective websites (flowinjection.com, mn-net.com, micrologylabs.com, and USGS.gov), enabling the EPA to conclude that the USGS methods and ATPs incorporated by reference are reasonably available.

C. Changes to 40 CFR 136.3 To Include New Versions of Approved Standard Methods

The EPA is proposing to approve new versions of Standard Methods methods previously approved in 40 CFR part 136. The newer versions provide clarifications or make editorial corrections. As was the case with the previous methods update rule (82 FR 40836-40941, August 28, 2017), the EPA generally proposes to approve and include in 40 CFR part 136 only the most recent version of a method published by the Standard Methods Committee. The EPA is proposing to list only one version of the method with the year of publication designated by the last four digits in the method number (e.g., Standard Methods Method 3111 B-2011). The date indicates the date of the specific revision to the method. This allows use of a specific method in any edition of the hard copy publication of Standard Methods for the Examination of Water & Wastewater (Standard Methods) that includes a method with the same method number and year of publication.

The proposed revisions to Standard Methods methods previously approved in 40 CFR part 136 will not affect the performance of the method. Below is a list of the Standard Methods methods the EPA is proposing to include in 40 CFR part 136. Each entry contains the proposed Standard Methods number and date, the parameter, and a brief description of the analytical method. The methods listed below are organized according to the table at 40 CFR part 136 in which they appear.

The EPA proposes to make the following changes to Tables IA and IH at 40 CFR part 136:

1. Standard Methods Method 9221 (B, E, F)-2014: Method 9221B-2014 Coliform (total); analyzes for total coliforms in non-potable waters using lauryl tryptose broth (LTB), all presumptive growth LTB tubes are confirmed in brilliant green lactose bile broth (BGLB). Method 9221E-2014 Coliform (fecal); analyzes all presumptive growth LTB tubes for fecal coliform using EC broth. Method 9221F-2014 E. coli; analyzes all presumptive growth LTB tubes for E. coli using EC-MUG. The number of positive tubes (BGLB, EC broth or EC-MUG) is used to determine the most probable number (MPN).

2. Standard Methods Method 9222 (B, D, I)-2015: Method 9222B-2015 Coliform (total); analyzes for total coliforms in non-potable waters by filtration through a 0.45-µm membrane filter and plated on mEndo or LES Endo agar. Method 9222D-2015 Coliform (fecal); analyzes for fecal coliforms in non-potable waters by filtration through a 0.45-µm membrane filter plated on mFC medium. Method 9222 I-2015 E. coli; membrane filtration (MF), analyzes presumptive positive filters from Method 9222B and 9222D using nutrient agar plates with MUG (NA-MUG) which are examined under a longwave UV lamp.

3. Standard Methods Method 9223B-2016, E. coli, multiple tube/multiple well. This method analyzes non-potable waters for E. coli using commercially available enzyme substrate media that is mixed with the sample and placed in multiple tubes or multiple well trays, incubated and examined under ambient light for Coliform (total) and under a longwave UV lamp for E. coli.

4. Standard Methods Method 9230 (B, C)-2013: Method 9230B-2013 Fecal Streptococci; analyzes non-potable waters for streptococci using azide dextrose broth (ADB), Presumptive positive ADB tubes are confirmed by streaking onto bile esculin azide agar (BEA). Method 9230C-2013 Enterococci; analyzes non-potable waters by filtration through a 0.45-µm membrane filter and plated on mE agar.

The EPA proposes to make the following changes to Table IB at 40 CFR part 136:

1. Standard Methods Methods: Method 2540B-2015, total solids; a sample aliquot is evaporated in a pre-weighed evaporating dish at 103-105 °C. Method 2540C-2015 filterable residue (total dissolved solids); a sample aliquot is filtered through a glass fiber filter and the filtrate is evaporated on a pre-weighed dish to constant weight at 180 °C. Method 2540D-2015 non-filterable residue (total suspended solids); a sample aliquot is filtered through a pre-weighed glass fiber filter which is then dried to constant weight at 103-105 °C. Method 2540E-2015 volatile residue (fixed and volatile solids); the residue obtained from the determination of total (Method 2540B), filterable (Method 2540C) or non-filterable residue (Method 2540D) is ignited at 550 °C in a muffle furnace. Method 2540E-2015 settleable residue (settleable solids); settleable matter is measured with an Imhoff cone either volumetrically or gravimetrically.

2. Standard Methods Method 4500-CN⁻ (B-G)-2016, cyanide: Cyanides are measured after preliminary treatment of samples to remove interferences (4500-CN⁻ B) and manual distillation with magnesium chloride (MgCl₂) (4500-CN⁻ C) followed by: Titration with silver nitrate (4500-CN⁻ D), spectrophotometric measurement after cyanide in the alkaline distillate is converted to CNCl (4500-CN⁻ E), potentiometric measurement using an ion selective electrode (4500-CN⁻ F), and cyanide amenable to chlorination (CATC) in which a portion of the sample is chlorinated at high pH and cyanide levels in the chlorinated sample are determined after manual distillation followed by titrimetric or spectrophotometric measurement. Amenable cyanide is calculated by the difference between the results for cyanide in the unchlorinated sample and the results for the chlorinated sample (4500-CN⁻ G).

3. Standard Methods Method 4500-NO₃⁻ D-2016, nitrate (as nitrogen), measured using an ion-selective electrode (ISE) that develops a potential across a thin, inert membrane holding in place a water-immiscible liquid ion exchanger.

4. Standard Methods Method 4500-NO₃⁻ (E, F, and H)-2016, nitrate-nitrite (as nitrogen): Nitrate is reduced to nitrite using a cadmium-copper column, followed by diazotization to form a colored azo dye, which is measured by colorimetry either manually (4500 NO₃⁻ E) or automated (4500 NO₃⁻ F); or by reduction of nitrate to nitrite using hydrazine followed by automated colorimetric measurement of nitrite after diazotization (4500 NO₃⁻ H).

5. Standard Methods Method 4500-NO₃⁻ (E and F)-2016, nitrite (as nitrogen), colorimetric: Bypasses the cadmium reduction step and measures nitrite after diazotization either by manual or automated colorimetric analysis.

6. Standard Methods Method 4500-O (B-F, and G)-2016, measurement of oxygen (dissolved), using the Winkler iodometric titration procedure with modifications to eliminate or minimize certain interferences if necessary based on sample type (4500-O B through F), or by use of polarographic or galvanic membrane electrodes (4500-O G).

7. Standard Methods Method 5210 B-2016, biochemical oxygen demand (BOD₅), dissolved oxygen depletion. The BOD₅ test is an indirect measurement of organic matter; it measures the change in DO concentration caused by microorganisms as they degrade organic matter in a sample held in a stoppered bottle incubated for 5 days in the dark at 20 °C.

8. Standard Methods Method 5310 (B, C)-2014, total organic carbon (TOC), combustion, heated persulfate or UV persulfate oxidation: Method 5310B-2014, high-temperature combustion; a sample aliquot is combusted, transported in a carrier gas stream and measured via a nondispersive infrared analyzer, or titrated coulometrically Method 5310C-2014, persulfate-ultraviolet or heated-persulfate oxidation method; persulfate oxidizes organic carbon, the produced CO₂ is then purged and measured by either nondispersive infrared (NDIR) analyzer, be coulometrically titrated, or separated from the liquid stream by a membrane that specifically allows CO₂ to pass into high-purity water where the change in the high-purity water's conductivity corresponds to the amount of CO₂ passing the membrane.

The EPA is also proposing one revision to a previously approved Standard Methods method for which the Standard Methods Committee has adopted updates. This modification includes minor procedural changes that do not affect the performance of the method.

The EPA proposes to make the following change to Table IA and Table IH at 40 CFR part 136:

1. The EPA proposes that the MPN method Standard Methods Method 9221 F.2-2014 be approved as an acceptable method for detecting thermotolerant coliforms and E. coli simultaneously. This method analyzes Coliform (fecal) and E. coli using EC broth with 4-methylumbelliferyl-β-D-glucuronide (EC-MUG) with inverted vials.

D. Changes to 40 CFR 136.3 To Include New Standard Methods Methods Based on Previously Approved Technologies

The EPA is proposing these changes based on the National Technology Transfer and Advancement Act of 1995 (NTTAA), Public Law 104-113, which states that federal agencies and departments shall use technical standards developed or adopted by the VCSBs if compliance would not be inconsistent with applicable law or otherwise impracticable. These methods submitted by the Standard Methods Committee are consistent with other methods already approved at 40 CFR part 136.

1. The EPA proposes to add Standard Methods Method 4500-CN⁻ N-2016 to Table IB for Cyanide, total. Cyanide is measured after preliminary treatment of samples and manual distillation with magnesium chloride (MgCl₂) followed by automated spectrophotometric measurement after conversion to CNCl. This method is similar to the currently approved EPA Method 335.4, USGS Method I-4302-85, and Lachat Method 10-204-00-1-X, and uses semi-automated spectrophotometric measurement of cyanide.

2. The EPA proposes to add Standard Methods Method 4500-NO₃⁻ I-2016 to Table IB for combined nitrate-nitrite, nitrite (bypass the reduction column) and nitrate by subtraction. Nitrate is reduced to nitrite using a cadmium-copper column followed by diazotization to form an azo dye which is measured by colorimetry. The cadmium reduction column may be by-passed for measurement of nitrite only. The value obtained for nitrite may be subtracted from the value obtained for combined nitrate-nitrite to calculate the concentration of nitrate. This method is similar to the currently approved EPA Method 353.2, Standard Methods Method 4500-NO₃⁻ F-2011, ASTM Method D3867-04 (A), and USGS Method I-2545-90, and uses automated cadmium reduction and spectrophotometric measurement of nitrite.

3. The EPA proposes to add Standard Methods Method 4500-NO₃⁻ J-2018 to Table IB for measurement of combined nitrate-nitrite, for measurement of nitrite when bypassing the enzymatic reduction step, and for measurement of nitrate by subtraction. Nitrate is reduced to nitrite by an enzymatic reaction. The nitrite is diazotized to yield an azo dye which is measured colorimetrically. The enzyme reduction step may be by-passed for measurement of nitrite singly. The value obtained for nitrite may be subtracted from the value obtained for combined nitrate-nitrite to calculate the concentration of nitrate. This method is similar to the currently approved NECi Method N07-0003, USGS Method I-2547-11, and USGS Method I-2548-11.

4. The EPA proposes to add Standard Methods Method 4500-O H-2016 to Table IB for dissolved oxygen. This method uses a luminescent-based sensor for measurement of dissolved oxygen. The method is similar to the currently approved Hach Method 10360, In-Situ Method 1002-8-2009, and ASTM Method D888-09 (C).

E. Changes to 40 CFR 136.3 To Include New Versions of Approved ASTM Methods

The EPA is proposing to approve new versions of ASTM methods previously approved in 40 CFR part 136 for the same reasons outlined in the first paragraph of Section IV.C above. These changes to currently approved ASTM methods in 40 CFR part 136 include minor clarifications and editorial changes, and in some instances, minor procedural changes. None of these proposed changes will affect the performance of the method. The following describes the changes to current ASTM methods that the EPA proposes to include in 40 CFR part 136. Each entry contains (in the following order): Proposed ASTM method number (the last two digits in the method number represent the year ASTM published), the parameter, a brief description of the analytical technique, and a brief description of any procedural changes in this revision from the last approved version of the method. The methods listed below are organized according to the table at 40 CFR part 136 in which they appear.

The EPA proposes the following changes to Table IB at 40 CFR part 136:

1. ASTM Method D511-14 (A, B), calcium and magnesium, titrimetric, (EDTA), AA direct aspiration: Method D511-14 A, titrimetric; the pH of the sample is adjusted to 10 (for calcium), then to 12-13 (for magnesium) and titrated with ethylenediamine tetraacetic acid (EDTA) to form complexes with calcium and magnesium ions which react with an indicator to form a colored product. The volume of titrant used to affect the color change is proportional to the concentrations of calcium and magnesium in the sample. Method D511-14 B, AA direct aspiration; the sample is acidified and analyzed by atomic absorption. The concentrations of calcium and magnesium in the samples are proportional to the amount of light absorbed during the analysis, and are determined in comparison to a standard curve.

This version adds specifications for filter paper.

2. ASTM Method D512-12 chloride ion (A, B), titrimetric (mercuric nitrate), titration (silver nitrate): Method D512-12A, titrimetric mercuric nitrate; the sample is acidified and titrated with mercuric nitrate in the presence of a diphenylcarbazonebromophenol blue indicator. Method D512-12B, titrimetric silver nitrate; sample pH is adjusted to phenolphthalein endpoint and titrated with silver nitrate in the presence of potassium chromate. The volume of titrant used to affect the color change in either method is proportional to the concentration of chloride in the sample. This version corrects one term in the calculation of the chloride calculation.

3. ASTM Method D516-16, sulfate ion, turbidimetric. In this method, sulfate ions are converted to barium sulfate to form a suspension. The turbidity of the suspension is measured with a nephelometer, spectrophotometer, or photoelectric colorimeter, and compared to a standard curve to determine the sulfate concentration in the sample. This version adds specifications for filter paper.

4. ASTM Method D858-17 (A-C), manganese, atomic absorption (AA) direct aspiration, AA furnace. The sample is acid digested and analyzed by direct aspiration atomic absorption or graphite furnace atomic absorption. The concentration of manganese in the sample is proportional to the amount of light absorbed and is determined in comparison to a standard curve. There are no procedural changes.

5. ASTM Method D859-16, silica, colorimetric, manual. In this method, soluble silica in the sample is reacted with molybdate then reduced to form a blue complex in solution. The intensity of the blue complex is determined with a spectrophotometer or filter photometer and the concentration of silica is determined by comparison with a standard curve. There are no procedural changes.

6. ASTM Method D888-12 (A-C) dissolved oxygen, Winkler, electrode, luminescent-based sensor: Method D888-12A measures dissolved oxygen using the Winkler iodometric titration procedure. The volume of titrant used is proportional to the concentration of dissolved oxygen in the sample. Method D888-12B measures dissolved oxygen in the sample with an electrochemical probe that produces an electrical potential which is logarithmically proportional to the concentration of dissolved oxygen in the sample. Method D888-12C measures dissolved oxygen with a luminescence-based sensor probe that employs frequency domain lifetime-based luminescence quenching and signal processing. This version adds information on a two-point calibration and updated performance information from an interlaboratory study to D888-12C.

7. ASTM Method D1067-16, acidity or alkalinity, electrometric endpoint or phenolphthalein endpoint; electrometric or colorimetric titration to pH 4.5, manual. The acidity or alkalinity of the sample is determined by titration to a specific pH endpoint which is determined by colorimetry or with a pH electrode. The acidity or alkalinity is proportional to the volume of titrant required to affect the pH change. There are no procedural changes.

8. ASTM Method D1068-15 (A-C), iron, AA direct aspiration; AA furnace; colorimetric (Phenanthroline): The sample is acid digested and analyzed by either direct aspiration atomic absorption, graphite furnace atomic absorption, or colorimetry. The concentration of iron in the sample is proportional to the amount of light absorbed and is determined in comparison to a standard curve. This version adds specifications for filter paper.

9. ASTM Method D1126-17, hardness, titrimetric (EDTA). The pH of the sample is adjusted and an indicator is added forming a red color. The mixture is titrated until the color changes from red to blue. The volume of titrant used to affect the color change is proportional to the hardness in the sample. There are no procedural changes.

10. ASTM Method D1179-16 (A, B); fluoride ion, manual distillation, electrode, manual: Method D1179A, manual distillation; the sample is distilled as hydrofluorosilic acid and determined by ion-selective electrode. Method D1179B, electrode; the fluoride ion is determined potentiometrically with an ion-selective electrode in conjunction without sample distillation. There are no procedural changes.

11. ASTM Method D1246-16, bromide ion, electrode. The bromide in the sample is determined potentiometrically with an ion-selective electrode, either through comparison to a standard curve or through a direct readout on the instrument. There are no procedural changes.

12. ASTM Method D1252-06 (A, B) (Reapproved 2012), chemical oxygen demand, titrimetric, spectrophotometric. This is the 2012 reapproval of the 2006 ASTM method: Method D1252-06A, titrimetric; measures the loss of the hexavalent dichromate ion by reflux digestion followed by titration. The chemical oxygen demand in the sample is determined by comparison to a standard curve. Method D1252-06B, spectrophotometric; uses a spectrophotometer to measure the loss of the hexavalent dichromate ion at 420 nm or the increase in the trivalent chromium ion at 600 nm, after closed digestion and determines the chemical oxygen demand by comparison to a standard curve. There are no procedural changes.

13. ASTM Method D1253-14, residual chlorine, amperometric direct. The concentration of chlorine in the sample is determined by titration with phenylarsine oxide, using an amperometric probe that responds to chlorine to determine when the titration is complete. The chlorine concentration in the sample is proportional to the volume of titrant used. There are no procedural changes.

14. ASTM Method D1426-15 (A, B), ammonia nitrogen, Nesslerization, electrode: Method D1426A, Nesslerization; an aliquot is Nesslerized and the ammonia content determined colormetrically. Method D1426B, electrode; ammonia is potentiometric determined using a gas-permeable ion-selective electrode, either through comparison to a standard curve or through a direct readout on the instrument using. A lengthy section of QC requirements was added to the Nesslerization procedure (D1426A) that parallels the QC discussion that was already in the B procedure. Both procedures added information on use of commercially prepared standards and filter paper.

15. ASTM Method D1687-17 (A-C), chromium (total) and dissolved hexavalent chromium, colorimetric (diphenyl-carbazide); AA direct aspiration; AA furnace: Method D1687-17A, chromium (dissolved); measures dissolved hexavalent chromium by reacting it with diphenyl-carbohydrazide to produce a reddish-purple color that is measured with a spectrophotometer or filter photometer. The concentration in the sample is proportional to the intensity of the color. Method D1687-17B, chromium (total); the sample is acid digested and analyzed by direct aspiration atomic absorption. Method D1687-17C, chromium (total); the sample is acid digested and analyzed by graphite furnace atomic absorption. The concentration of total chromium in the sample is proportional to the amount of light absorbed during the analysis and is determined in comparison to a standard curve. The changes mirror those for the other metals methods. The QC frequencies for method blank, continuing calibration verification (CCV), continuing calibration blank (CCB), matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples.

16. ASTM Method D1688-17 (A-C), copper, AA direct aspiration, AA furnace. The sample is acid digested and analyzed by direct aspiration atomic absorption (D1688-17A and B) or graphite furnace atomic absorption (D1688-17B). The concentration of copper in the sample is proportional to the amount of light absorbed and is determined in comparison to a standard curve. The changes mirror those for the other metals methods. The proposed changes also clarify the requirements for a multi-point calibration by discussing it in the calibration section as well as the QC section of all three procedures. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples.

17. ASTM Method D1691-17 (A, B), zinc, AA direct aspiration. Method D1691-17A; the sample is acid digested and analyzed by direct aspiration atomic absorption. Method D1691-17B; the sample is processed by chelation-extraction and analyzed by atomic absorption. The concentration of zinc in the sample is proportional to the amount of light absorbed and is determined in comparison to a standard curve. The changes mirror those for the other metals methods. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples.

18. ASTM Method D1783-01 (A, B) (Reapproved 2012), phenols, manual distillation followed by manual colorimetric (4AAP). The sample is distilled, the distillate pH is adjusted to 10.0, and reacted with 4-aminoantipyrine to form a colored product. In Method D1783-01A, the colored product is extracted from the sample with chloroform and measured with a photometer at 460 nm. In Method D1783-01B, the colored product is measured without extraction, using a photometer at 510 nm. The concentration of phenolics is determined in comparison to a standard curve. There are no procedural changes.

19. ASTM Method D1886-14 (A-C), nickel AA direct aspiration, chelation extraction AA and AA furnace. Method D1886-14A, the sample is acid digested and analyzed by direct aspiration atomic absorption. Method D1886-14B, the sample is acid digested and the nickel chelated and extracted. The extract is analyzed by direct aspiration atomic absorption. Method D1886-14C, the sample is acid digested and analyzed by graphite furnace atomic absorption. The concentration of nickel in the sample is proportional to the amount of light absorbed during the analysis and is determined in comparison to a standard curve. The changes mirror those for the other metals methods. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples.

20. ASTM Method D2036-09 (A, B) (Reapproved 2015), A, total cyanide, manual distillation followed by gas diffusion amperometry, titrimetric, spectrophotometric, ion chromatography, ion selective electrode, B, available (amenable) cyanide, manual distillation followed by titrimetric or spectrophotometric. The cyanide in the sample is distilled and trapped in a sodium hydroxide solution. Method D2036-09A, the cyanide is treated with strong acid and a catalyst during distillation and measured by titration, gas diffusion amperometry, spectrophotometry, ion-selective electrode, ion chromatography, or flow injection analysis. Method D2036-09B, cyanide amenable to chlorination is determined by comparing the results for one sample aliquot analyzed for total cyanide and a second aliquot that is treated with calcium hypochlorite prior to analysis by Method D2036-09A. There are no procedural changes.

21. ASTM Method D2972-15 (A-C), arsenic, colorimetric, AA gaseous hydride, AA furnace. The sample is digested with nitric and sulfuric acids. Method D2972-15A, arsenic is trapped in a solution of silver diethyldithiocarbamate in pyridine which produces a red-colored product that is analyzed photometrically by comparison to a standard curve. Method D2972-15B, arsenic in the digested sample is determined by hydride generation atomic absorption. Method D2972-15C, arsenic in the digested sample is determined by graphite furnace atomic absorption. The changes mirror those for the other metals methods. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples.

22. ASTM Method D3223-17, total mercury, cold vapor, manual. Mercury in the sample is converted to the mercuric ion which is reduced to elemental mercury, purged from the sample, and analyzed by cold vapor atomic absorption. The changes mirror those for the other metals methods, but this version changes the acceptance limit for the CCV from 10% to 15% and adds a requirement for a CCB. Given that the most comparable EPA procedure, Method 245.1, does not include a CCV requirement or an acceptance limit, the change of the acceptance limit from 10% to 15% in the revised ASTM method represents a requirement that is more stringent than that required in the EPA's procedure and therefore, the change to the ASTM method is not an impediment to its approval.

23. ASTM Method D3373-17, vanadium, AA furnace. The sample is digested with nitric acid and analyzed by graphite furnace atomic absorption. The concentration of vanadium in the sample is proportional to the amount of light absorbed during the graphite furnace atomic absorption analysis and is determined in comparison to a standard curve. The changes mirror those for the other metals methods. The proposed changes clarify the requirements for a multi-point calibration by discussing it in the calibration section as well as the QC section of all three procedures. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples.

24. ASTM Method D3557-17 (A-D), cadmium, AA direct aspiration, voltammetry, AA furnace. Method D3557-17A, the sample is acid digested and analyzed by direct aspiration atomic absorption. Method D3557-17B, the sample is acid digested, the digestate is chelated and extracted. The extract analyzed by direct aspiration atomic absorption. Method D3557-17C, the sample is acid digested and analyzed by differential pulse anodic stripping voltametry. Method D3557-17D, the sample is digested with nitric acid and analyzed by graphite furnace atomic absorption. The concentration of cadmium in the sample is determined in comparison to a standard curve. The changes mirror those for the other metals methods. The proposed changes also clarify requirements for a multi-point calibration by discussing it in the calibration section as well as the QC section of all three procedures. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples, as opposed to 10 samples previously.

25. ASTM Method D3558-15 (A-C), cobalt, AA direct aspiration, chelation extraction AA, and AA furnace. Method D3558-15A, the sample is acid digested and analyzed by direct aspiration atomic absorption. Method D3558-15B, the sample is acid digested, chelated and extracted. The extract is analyzed by direct aspiration atomic absorption. Method D3558-15C, the sample is acid digested and analyzed by graphite furnace atomic absorption. The concentration of cobalt in the sample is proportional to the amount of light absorbed during the analysis and is determined in comparison to a standard curve. The changes mirror those for the other metals methods. The proposed changes also clarify the requirements for a multi-point calibration by discussing it in the calibration section as well as the QC section of all three procedures. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch of up to 20 samples, as opposed to 10 samples previously.

26. ASTM Method D3559-15 (A-D), lead, AA direct aspiration, voltammetry, AA furnace. Method D3559-15A, the sample is acid digested and analyzed by direct aspiration atomic absorption. Method D3559-15B, the sample is acid digested, chelated and extracted. The extract is analyzed by direct aspiration atomic absorption. Method D3559-15C, the sample is acid digested and analyzed by differential pulse anodic stripping voltametry. Method D3559-15D, the sample is digested with nitric acid and analyzed by graphite furnace atomic absorption. The changes mirror those for the other metals methods. The proposed changes also clarify the requirements for a multi-point calibration by discussing it in the calibration section as well as the QC section of all three procedures. It also adds a new section with the QC requirements to the direct AA procedure that was already present in the AA furnace portion of this procedure (D3559-15 [D]).

27. ASTM Method D3590-17 (A, B), total Kjeldahl nitrogen, manual digestion and distillation or gas diffusion; semi-automated block digester colorimetric (distillation not required). Method D3590-17A, the sample is chemically processed to covert nitrogenous compounds to ammonia, then distilled or subjected to a gas diffusion system which releases the ammonia for analysis by colorimetry, titrimetry, or potentiometry. Method D3590-17B, the digestion and distillation are accomplished by a semi-automated system and the resulting ammonia is determined by colorimetry of the salicylate/nitroprusside Berthelot reaction product. This version changes the acceptance limit for the CCV from 10% to 15% and adds a requirement for a CCB. Given that neither the approved Standard Methods method for measuring ammonia after the TKN digestion, nor the comparable EPA Method 350.1, include a CCV requirement or an acceptance limit, the change of the acceptance limit from 10% to 15% in the revised ASTM method represents a requirement that is more stringent than that required in other approved procedures and therefore is not an impediment to its approval.

28. ASTM Method D3645-15, beryllium (A, B), AA direct aspiration AA furnace. Method D3645-15A, the sample is acid digested and analyzed by direct aspiration atomic absorption. Method D3645-15B, the sample is digested with nitric acid and analyzed by graphite furnace atomic absorption. This version adds specifications for filter paper. The proposed changes also clarify the requirements for a three-point calibration by discussing it in the calibration section as well as the QC section of both procedures. It also adds a new section with the QC requirements to the direct aspiration AA procedure that was already present in the AA furnace portion of this procedure (D3645-15B).

29. ASTM Method D3859-15 (A, B), selenium, AA gaseous hydride, AA furnace. In Method D3859-15A, the selenium in the sample is converted to gaseous selenium hydride, which is then analyzed by flame atomic absorption. Method D3859-15B, the selenium in the sample is converted to gaseous selenium hydride and analyzed by graphite furnace atomic absorption. The changes to the gaseous hydride portion of the method clarify the requirement for a 6-point calibration curve by discussing it in the calibration section as well as the QC section. The version adds an updated discussion of block digesters. The QC frequencies for method blank, CCV, CCB, matrix spike, and duplicate analyses are now based on a laboratory-defined batch, as opposed to an otherwise undefined “batch.” The GFAA portion contains similar editorial and technical changes. Technical changes also include specifications for filter paper. The calibration requirement for three standards has been clarified by discussing it in the calibration section as well as the QC section.

30. ASTM Method D3867-16 (A, B) nitrate-nitrite, nitrite and nitrate; automated cadmium reduction, manual cadmium reduction, bypass cadmium reduction and subtraction. The combination of nitrate and nitrite in the sample is determined by reducing the nitrate to nitrite using a cadmium-copper column, diazotizing and analyzing in either a manual or automated spectrophotometric system. A second aliquot of the sample can be analyzed without use of the cadmium reduction column to determine the concentration of nitrate by difference. The changes add more detailed QC requirements, including specifically calling out the laboratory control sample (LCS), method blank, and matrix spike analyses. The 2016 version adds specifications for filter paper. It also changes the LCS frequency from 10% of samples to once per batch (up to 20) and sets the CCB and CCV frequencies at 10%.

31. ASTM Method D4190-15, dissolved elements and total recoverable elements, direct current plasma. The concentrations of various metal elements are determined by acidifying an aliquot of the sample and analyzing it by direct current plasma spectrometry, monitoring a specific wavelength of light for each element. There is one change that adds a requirement to run at least four calibration standards for all metals, as opposed to running four standards for only lithium to demonstrate linearity.

32. ASTM Method D4282-15, free cyanide, manual micro-diffusion and colorimetry. The sample is treated and allow for free cyanide diffuse into a sodium hydroxide solution. An aliquot of that solution is treated to form a colored product that is measured with a spectrophotometer at 580 nm. There are no procedural changes.

33. ASTM Method D4327-17, inorganic anions (fluoride, bromide, chloride, nitrite, nitrate, orthophosphate, and sulfate), ion chromatography. An aliquot of the sample in injected into an ion chromatograph equipped with an anion exchange column and a conductivity detector. The anions are identified based on their retention times and concentrations are determined by comparison to a standard curve. Changes include updating the equipment and reagent descriptions to reflect more modern instrumentation, such as the use of hydroxide eluents and eluent regeneration systems.

34. ASTM Method D4382-18, barium, AA furnace. The sample is digested with nitric acid and analyzed by graphite furnace atomic absorption. The only procedural change is to the description of the hot block digester equipment. The new version specifies the capability to heat samples between 65 and 95 degrees C, instead of “approximately 95 degrees C.” That change recognizes the operational characteristics of hot block digesters that will experience a temperature drop below 95 degrees when samples are added. This should not adversely affect use of this method for barium.

35. ASTM Method D4658-15, sulfide ion, ion selective electrode. The sample is treated with a sulfide antioxidant buffer to create a highly alkaline solution. Sulfide in the sample is measured potentiometrically with an ion-selective electrode. There are no procedural changes.

36. ASTM Method D4839-03 (Reapproved 2017), total organic carbon; heated persulfate or UV persulfate oxidation. The sample is sparged with an inert gas to remove dissolved inorganic carbon and then treated with persulfate and either heat or UV radiation to convert organic carbon to carbon dioxide. The carbon dioxide is measured with an infra-red detector. There are no procedural changes.

37. ASTM Method D5257-17, dissolved hexavalent chromium, ion chromatography. The sample is filtered and buffered and an aliquot injected into an ion chromatograph that separates hexavalent chromium from other ions. The eluent from the chromatograph is treated with an acidic solution of diphenylcarbohydrazide to form a violet-colored product that is measured with a photometric detector at 530 nm. The changes add a few additional warnings or recommendations.

38. ASTM Method D5673-16, dissolved elements and total-recoverable elements, ICP/MS. The sample is acid digested and analyzed by inductively coupled plasma/mass spectrometry. Gold was added to the list of target analytes. Some of the changes address the analysis of gold.

39. ASTM Method D6508-15, inorganic anions (fluoride, bromide, chloride, nitrite, nitrate, orthophosphate, and sulfate), capillary ion electrophoresis with indirect UV detection. An aliquot of the sample in injected into a capillary ion electrophoresis instrument where the anions are separated in an applied electric field through a fused silica capillary. The analytes are detected by a UV detector and their concentrations are determined by comparison to a standard curve. There are no procedural changes.

40. ASTM Method D6888-16, available cyanide, flow injection and ligand exchange, followed by gas diffusion amperometry. An aliquot of the sample is introduced into a flow injection analysis instrument, where available cyanide is acidified to form hydrogen cyanide which diffuses through a hydrophobic gas diffusion membrane into an alkaline solution and is detected amperometrically with a silver electrode. This version adds a new mixed ligand exchange reagent, but also retains the original two ligand reagents that had to be mixed together during the testing.

41. ASTM Method D6919-17, inorganic alkali and alkaline earth cations and ammonium (ammonium, calcium magnesium, potassium and sodium), ion chromatography. An aliquot of the sample in injected into an ion chromatograph equipped with a cation exchange column and a conductivity detector. The cations are identified based on their retention times and concentrations are determined by comparison to a standard curve. There are no procedural changes.

42. ASTM Method D7237-15 (A), free cyanide, flow injection, followed by gas diffusion amperometry. An aliquot of the sample is introduced into a flow injection analysis instrument, where it mixes with a phosphate buffer to release hydrogen cyanide which diffuses through a hydrophobic gas diffusion membrane into an alkaline solution and is detected amperometrically with a silver electrode. There are a few additions and changes to the newer version of note. The statement of the applicable range of the method in Section 1.4 has been changed at the low end, from 2 to 500 µg/L to 5 to 500 µg/L. New information about interferences from floatation reagents has been added to Section 6.3. New materials in Section 8 discuss alternative reagents or concentrations.

43. ASTM Method D7284-13 (Reapproved 2017), total cyanide, manual distillation with MgCl₂ followed by flow injection, gas diffusion amperometry. The sample is distilled with acid and a magnesium chloride catalyst to release cyanide to a sodium hydroxide solution. An aliquot of the sodium hydroxide solution is introduced into a flow injection analysis instrument, where it is acidified and the hydrogen cyanide diffuses through a hydrophobic gas diffusion membrane into an alkaline solution and is detected amperometrically with a silver electrode. There are no procedural changes.

44. ASTM Method D7511-12 (Reapproved 2017), total cyanide, segmented flow injection, in-line ultraviolet digestion, followed by gas diffusion amperometry. The sample is introduced into a segmented flow injection analysis instrument, where UV light releases cyanide from cyanide complexes. The sample is then acidified in the instrument and the produced cyanide gas is detected amperometrically with a silver electrode. There are no procedural changes.

45. ASTM Method D7573-09 (Reapproved 2017), total organic carbon, combustion. The sample is sparged with an inert gas to remove dissolved inorganic carbon, acidified, and then combusted at high temperature convert organic carbon to carbon dioxide. The carbon dioxide is measured with an infra-red detector. There are no procedural changes.

The EPA proposes the following changes to Table IC at 40 CFR part 136:

1. ASTM Method D7065-17, nonylphenol, bisphenol A, p-tert-octylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate, gas chromatography/mass spectrometry (GC/MS). The sample is extracted with methylene chloride and the extract is injected into a gas chromatograph-mass spectrometer. The target analytes are identified by retention time and mass spectra and quantified using internal standards and a calibration curve. There are a large number of editorial and structural changes in the document. A new QC section has been added.

F. Changes to 40 CFR 136.3 To Include a New ASTM Method Based on Previously Approved Technologies

The EPA is proposing these changes based on the National Technology Transfer and Advancement Act of 1995 (NTTAA), Public Law 104-113, which states that federal agencies and departments shall use technical standards developed or adopted by the VCSBs if compliance would not be inconsistent with applicable law or otherwise impracticable. This method submitted by ASTM is consistent with other already approved methods.

1. The EPA proposes to add ASTM Method D7781-14 to Table IB for nitrate-nitrite, nitrite (bypass the enzymatic reduction step) and nitrate by subtraction. Nitrate is reduced to nitrite by an enzymatic reaction. The nitrite is diazotized to yield an azo dye which is measured colorimetrically. The enzyme reduction step may be by-passed for measurement of nitrite singly. The value obtained for nitrite may be subtracted from the value obtained for combined nitrate-nitrite to calculate the concentration of nitrate. This method is similar to the currently approved NECi Method N07-0003, USGS Method I-2547-11, and USGS Method I-2548-11.

G. Changes to 40 CFR 136.3 To Include New United States Geological Survey (USGS) Inorganic Methods Based on Previously Approved Technologies

1. The EPA proposes to add USGS Method I-2057-85 titled “Anions, ion-exchange chromatographic, automated,” to Table IB for bromide. Method I-2057-85 is an ion chromatography method that lists several target analytes: bromide, chloride, fluoride, nitrate, nitrite, orthophosphate, and sulfate. These are the same target analytes found in EPA Methods 300.0 (Part A) and 300.1 (Part A). Both EPA methods are approved in 40 CFR part 136 for the target analytes listed in the methods. USGS Method I-2057-85 is similar to EPA Method 300.0, in that it uses ion chromatography with a sodium bicarbonate/sodium carbonate eluent and has the same target analyte list. The two methods specify different columns and eluent concentrations, but rely on essentially the same underlying chemistry and determinative technique as other ion chromatography methods approved at 40 CFR part 136 for measurement of bromide. That is, the sample is introduced into an ion chromatograph. The anions of interest are separated and measured, using a system comprised of a guard column, analytical column, suppressor device, and conductivity detector.

2. The EPA proposes to add USGS Method I-2522-90 titled “Nitrogen, ammonia, colorimetry, salicylate-hypochlorite, automated-segmented flow” to Table IB for ammonia. USGS Method I-2522-90 uses the same underlying chemistry and determinative technique as other methods approved at 40 CFR part 136 for measurement of ammonia. The method is similar to other approved methods, such as EPA Method 350.1, Standard Methods Method 4500-NH3 G, and USGS Method I-4523-85, which rely on the Berthelot reaction. USGS Method I-2522-90 uses a modified version of the Berthelot reaction in which salicylate and hypochlorite react with ammonia in the presence of ferricyanide ions to form the salicylic analog of indophenol blue dye. The resulting color is directly proportional to the concentration of ammonia present and is measured using automated spectrophotometry. This is a well-documented modification to the Berthelot reaction used in EPA Method 351 and is specifically allowed in Table IB.

3. The EPA proposes to add USGS Method I-2540-90 titled “Nitrogen, nitrite, colorimetry, diazotization, automated-segmented flow” to Table IB for nitrite. USGS Method I-2540-90 employs the same underlying chemistry and determinative technique as other methods approved at 40 CFR part 136 for measurement of nitrite. The method is similar to other methods approved at 40 CFR part 136 for measurement of nitrite, including USGS Method I-4540-85, which uses an automated-segmented flow analyzer (Technicon AA II). Method I-2540-90, nitrite reacts with sulfanilamide under acidic conditions to form a diazo compound which is coupled with N-1-naphthylethylenediamine dihydrochloride to form a red compound, the absorbance of which is measured using an automated-segmented flow, spectrophotometry.

4. The EPA proposes to add USGS Method I-2601-90 titled “Phosphorus, orthophosphate, colorimetry, phosphomolybdate, automated-segmented flow” to Table IB for orthophosphate. USGS Method I-2601-90 employs the same underlying chemistry and determinative technique as other methods approved in 40 CFR part 136 for measurement of orthophosphate. Orthophosphate reacts with ammonium molybdate in acidic solution to form phosphomolybdic acid, which upon reduction with ascorbic acid produces an intensely blue complex the absorbance of which is measured using automated spectrophotometry. Antimony potassium tartrate is added to increase the rate of reduction. The method is similar to other approved methods, such as USGS Method I-4601-85 which uses an automated-segmented flow analyzer (Technicon AA II). The submitted USGS Method I-2601-90 also uses an automated-segmented flow analyzer (Alpkem rapid flow analyzer). It should be noted that the approved USGS Method I-4601-85 has two parameter codes listed:

a. Phosphorus, orthophosphate, dissolved, I-2601-85 (mg/L as P);

b. Phosphorus, orthophosphate, total, I-4601-85 (mg/L as P).

Although USGS Method I-4601-85 is listed in Table IB, samples to be used for measurement of orthophosphate are to be filtered upon collection per Table II. Therefore, the correct parameter code listed for the method should have been I-2601-85. I-2601-90 is just an updated version of that method (parameter code). In Section 3—Interferences, USGS Method I-2601-85 states: “Because as phosphorus is easily adsorbed on sediment, the orthophosphate recovered from the supernatant solution above a water-suspended sediment after some time has elapsed may be less than the orthophosphate that would have been determined in the filtrate from a sample filtered at the time of collection. The amount recovered may also depend on the type of sediment (clay, sand, etc.).”

5. The EPA proposes USGS Method I-4472-97 titled “Metals, Acid Digestion, Whole-Water Recoverable, inductively coupled plasma-mass spectrometry” to be added to Table IB for certain metals by ICP/MS. USGS Method I-4472-97 is an ICP/MS method that was previously listed under the same method number as the USGS ICP/AES Method I-4471-97 and was split out and assigned a unique method number by USGS in 2003. The EPA proposes to add this to Table IB on the line for ICP/MS and replace USGS Method I-4471-97 as an approved method for measurement of the following 16 elements: aluminum, antimony, barium, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, silver, thallium and zinc. USGS Method I-4472-97 relies on the same underlying chemistry and determinative technique as other ICP/MS methods approved at 40 CFR part 136 for measurement of the same 16 elements (e.g., EPA Method 200.8 and Standard Methods Method 3125 B) where analytes in the sample are solubilized by gentle refluxing with acids and then measured using inductively coupled plasma-mass spectrometry.

H. Changes to 40 CFR 136.3 To Include New United States Geological Survey (USGS) Organic Methods Based on Previously Approved Technologies

1. The EPA proposes to add USGS Method O-4127-96 titled “Determination of 86 Volatile Organic Compounds in Water by Gas Chromatography/Mass Spectrometry, Including Detections Less Than Reporting Limits” to Table IC for certain organic compounds. USGS Method O-4127-96 relies on the same underlying chemistry and determinative technique as other methods approved at 40 CFR part 136 for measurement of the analytes for which the method is being proposed. Volatile organic compounds are extracted by purging with Helium, collecting onto a sorbent trap, thermally desorbed, separated by a gas chromatographic capillary column, and finally determined by a full-scan quadrupole mass spectrometer. Compound identification is confirmed by the gas chromatographic retention time and by the resultant mass spectrum, typically identified by three unique ions.

2. The EPA Proposes to add USGS Method O-4436-16 titled “Determination of Heat Purgeable and Ambient Purgeable Volatile Organic Compounds in Water by Gas Chromatography/Mass Spectrometry” to Table IC for certain organic compounds. USGS Method O-4436-16 relies on the same underlying chemistry and determinative technique as other methods approved at 40 CFR part 136 for measurement of the analytes for which the method is being proposed. Volatile organic compounds are extracted from a water sample and compounds are trapped in a tube containing a suitable sorbent materials and then thermally desorbed into a capillary gas chromatographic column interfaced to a mass spectrometer system. Selected compounds are identified by using strict qualification criteria, which include analyzing standard reference materials and comparing retention times and relative ratios of the mass spectra. Compounds are quantitated using internal standard procedures.

I. Changes to 40 CFR 136.3 To Include Alternate Test Procedures (ATPs)

To promote method innovation, the EPA maintains a program that allows method developers to apply for EPA review and potential approval of an alternative method to an existing approved method. This ATP program is described for CWA applications at 40 CFR 136.4 and 136.5. The EPA is proposing three ATPs for nationwide use. Based on the EPA's review, the performance of these ATPs is equally effective as other methods already approved for measurement. The ATP applicants supplied EPA with study reports that contain the data from their validation studies. These study reports and the letters documenting EPA's review are contained as supporting documents within the docket for this proposed rule. These proposed new methods include: FIAlab Method 100, “Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Fluorescence Detector Analysis,” MACHEREY-NAGEL GmbH and Co. Method 036/038 NANOCOLOR® COD LR/HR, “Spectrophotometric Measurement of Chemical Oxygen Demand in Water and Wastewater,” and Micrology Laboratories, LLC. KwikCount^TM EC Medium Escherichia coli (E. coli) enzyme substrate test, “Rapid Detection of E. coli in Beach Water by KwikCount^TM EC Membrane Filtration.” Descriptions of these new methods proposed for approval are as follows:

1. FIAlab Instruments, Inc. Method 100, “Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Fluorescence Detector Analysis,” dated April 4, 2018 (FIAlab Instruments, Inc. 2018a). FIAlab Method 100 uses automated flow injection analysis with gas diffusion and fluorescence detector analysis to determine concentrations of ammonia in wastewater, ambient water, and Kjeldahl digestates. The method involves the following steps:

• The sample is introduced to the analyzer where it is made alkaline with sodium hydroxide;
• Ammonia is separated from the sample matrix by passage through a gas diffusion cell;
• After separation in the gas diffusion cell, ammonia is reacted with o-phthalaldehyde to form a fluorescent compound;
• The reaction product is detected by a fluorimeter and the response is directly proportional to the concentration of ammonia in the sample.

FIAlab Method 100 can be obtained from FIAlab Instruments, Inc., 334 2151 N Northlake Way, Seattle, WA 98103. Telephone: 425-376-0450.

2. MACHEREY-NAGEL GmbH and Co. Method 036/038 NANOCOLOR® COD LR/HR, “Spectrophotometric Measurement of Chemical Oxygen Demand in Water and Wastewater,” Revision 1.5, dated, May 2018 (MACHEREY-NAGEL GmbH and Co. 2018a). MACHEREY-NAGEL Method 036/038 NANOCOLOR® COD LR/HR is a manual method that uses spectrophotometry to measure chemical oxygen demand in wastewater. The method involves the following steps:

• Chemical Oxygen Demand (COD) is defined as the mg of oxygen (O₂) consumed per liter of sample following dichromate and sulfuric acid digestion;
• A sample is heated for two hours with a strong oxidizing agent, potassium dichromate. Oxidizable organic compounds react, reducing the dichromate ion (Cr₂ O₇²⁻) to the green chromic ion (Cr³⁺);
• When the COD LR 150 test kit is used, the amount of Cr⁶⁺ remaining after digestion is determined;
• When the COD HR 1500 test kit is used, the amount of Cr³⁺ produced is determined.

MACHEREY-NAGEL GmbH and Co. Method 036/038 NANOCOLOR® COD LR/HR, can be obtained from MACHEREY-NAGEL GmbH and Co., 2850 Emrick Blvd., Bethlehem, PA 18020. Telephone: 888-321-6224.

3. Micrology Laboratories LLC. KwikCount^TM EC Medium E. coli enzyme substrate test, “Rapid Detection of E. coli in Beach Water by KwikCount^TM EC Membrane Filtration” uses a membrane filtration procedure for rapid detection and enumeration of E. coli in ambient water. The method involves the following steps:

• A water sample is filtered through a 0.45-μm pore size, 47-mm diameter membrane filter;
• The filter is then placed into a 50-mm plate containing an absorbent pad containing KwikCount^TM EC broth;
• Plates are incubated at 41 ± 0.5 °C for 8-10 hr. The plates are then viewed in the dark using a long-wave UV light and fluorescent colonies are counted as E. coli.

The KwikCount^TM EC Medium E. coli enzyme substrate test can be obtained from Micrology Laboratories, LLC, 1303 Eisenhower Drive, Goshen, IN 46526. Telephone: 574-533-3351.

J. Changes to 40 CFR 136.3, Tables IA, IB, and IH

The EPA is proposing the following changes to 40 CFR 136.3, Tables IA and IH:

1. Table IA: Moving Colilert-18 from Parameter #1 Coliform (fecal), number per 100 mL or number per gram dry weight, to Parameter #2 Coliform (fecal), (number per 100 mL), to eliminate confusion as to whether it is approved for sewage sludge in addition to wastewater.

2. Table IA: Adding E. coli, number per 100 mL—MF, two-step, Standard Methods Method 9222 B/9222 I, to the table along with footnote 31 “Subject coliform positive samples determined by 9222 B-2015 or other membrane filter procedure to 9222 I-2015 using NA-MUG media.” The method was inadvertently omitted from Table IA when Table IA was split into two tables (IA and IH) in an earlier rulemaking; the addition corrects that error.

3. Table IA: Revising Parameter #2 Coliform (fecal), deleting “in presence of chlorine,” number per 100 mL. The phrase “in the presence of chlorine” caused confusion because the methods cited were the same for the analyte/matrix combination that did not state “in the presence of chlorine.” The approved methods did not change.

4. Table IA: Deleting Parameter #4 Coliform (total) in presence of chlorine, number per 100 mL. Except for “MF with enrichment,” all the methods were duplicative (e.g., Parameters #3 and #4). No approved methods for coliform (total) were removed from Table IA.

5. Table IH: Deleting Parameters #2 Coliform (fecal) in presence of chlorine, number per 100 mL and #4 Coliform (total) in presence of chlorine, number per 100 mL. Except for “MF with enrichment” for coliform (total), all the methods were duplicative (e.g., Parameters #1 and #2). In addition to the methods being duplicative, Table IH is for ambient water which would not be expected to contain chlorine. No approved methods for coliform (fecal) or coliform (total) were removed from Table IH. The remaining parameters are renumbered.

6. Tables IA and IH: Revising footnote 13 to Table IA and footnote 12 to Table IH as follows “These tests are collectively known as defined enzyme substrate tests.” The remaining text, “where, for example, a substrate is used to detect the enzyme β-glucuronidase produced by E. coli” has been deleted because the example has caused some confusion to stakeholders.

7. Tables IA and IH: Adding Quanti-Tray®/2000 as an option to footnotes 13 (IH), 15 (IH), 16 (IA) and 18 (IA). The addition of Quanti-Tray®/2000 is to address matrices with high bacterial concentrations and to ensure Tables IA and IH are accurate and consistent.

8. Tables IA and IH: Adding footnote 30 to Table IA and footnote 27 to Table IH to specify a verification procedure. The footnotes contain the following language: “On a monthly basis, at least ten sheen colonies from positive samples must be verified using Lauryl Tryptose Broth and brilliant green lactose bile broth, followed by count adjustment based on these results; and representative non-sheen colonies should be verified using Lauryl Tryptose Broth. Where possible, verifications should be done from randomized sample sources.” Adding the footnotes address the change in Standard Methods Method 9222 B-2015 that stated that five typical and five atypical colonies should be verified per membrane, which could be burdensome to laboratories analyzing samples other than drinking water. In most cases, analysis of ambient waters and wastewaters could result in multiple plates per sample with typical and atypical colonies, whereas drinking water analyses would seldom result in any typical or atypical colonies. In addition, the language in footnotes 29 (IA) and 26 (IH), was revised as follows “the medium” was replaced with “positive samples” for clarity and consistency.

9. Tables IA and IH: Adding footnote 32 to Table IA and footnote 30 to Table IH. The footnotes contain the following language “Verification of colonies by incubation of BHI agar at 10 ± 0.5 °C for 48 ± 3 h is optional.” As per the Errata to the 23rd Edition of Standard Methods for the Examination of Water & Wastewater, “Growth on a BHI agar plate incubated at 10 ± 0.5 °C for 48 ± 3 h is further verification that the colony belongs to the genus Enterococcus.”

10. Table IH: Deleting “or number per gram dry weight” from Parameter #1. Table IH is specifically for ambient waters, which does not require reporting results on a per gram dry weight basis.

11. Table IH: Adding the Alternate Test Procedure KwikCount^TM EC for E. coli, number per 100 mL under “Other.”

12. Table IH: Adding EPA Method 1623.1 for Parameters 6 and 7. EPA Method 1623.1 includes updated acceptance criteria for IPR, OPR, and MS/MSD, and clarifications and revisions based on the use of EPA Method 1623 and technical support questions over the past 19 years. Both methods 1623 and 1623.1 will be listed as approved in the MUR because use of either method is acceptable.

13. Table IH: Deleting footnote 5, “Because the MF technique usually yields low and variable recovery from chlorinated wastewaters, the Most Probable Number method will be required to resolve any controversies.” Table IH is specifically for ambient waters, so the footnote is not applicable. The remaining footnotes are renumbered accordingly.

14. Table IH: Revising footnote 20, to reference only EPA Method 1604. The literature reference was deleted from the footnote because it resulted in confusion as to whether EPA Method 1604 provided all the necessary information required by stakeholders to conduct analyses of ambient waters under the CWA.

K. Changes to Table II at 40 CFR 136.3(e) to Required Containers, Preservation Techniques, and Holding Times

The EPA is proposing to update footnote 6 to the preservation and holding time requirements for cyanide to cite the latest version of ASTM method D7365-09a that was reapproved in 2015. The recommended sampling and preservation procedures in the ASTM method have not changed since 2009, but the change to footnote 6 will simplify identification of the current method that is available from ASTM International.

The EPA is proposing to add footnote 9 to the preservation and holding time requirements to the purgeable halocarbons entry. This will allow the flexibility to collect a single sample with no acidification to be used for analysis of both purgeable halocarbons and purgeable aromatic hydrocarbons within seven days of collection, or to collect a single sample with acidification to be used for analysis of both purgeable halocarbons (except 2-CEVE) and purgeable aromatic hydrocarbons within the 14-day maximum holding time specified in Table II for both classes of compounds. The added flexibility is consistent with historical requirements for preservation in 40 CFR part 136 and holding time requirements in other EPA program methods, such as the SW-846 methods in the Office of Land and Emergency Management. This is part of the EPA's ongoing effort to harmonize methods between EPA programs, as requested by the Environmental Laboratory Advisory Board (ELAB).

Footnote 9 to Table II states: “If the sample is not adjusted to pH 2, then the sample must be analyzed within seven days of sampling.”

L. Changes to 40 CFR 136.6 Method Modifications and Analytical Requirements

In response to requests from ELAB and the Independent Laboratories Institute (ILI), the EPA is proposing to add a new paragraph (b)(4)(xviii) to 40 CFR 136.6 that explicitly allows the use of closed-vessel microwave digestion as a modification to the approved metals digestion procedure that does not require prior approval. Microwave digestion has the same fundamental chemistry as a hot plate digestion, both the microwave and hot plate serve the same function as heat sources.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Review and Executive Order 13563: Improving Regulation and Regulatory Review

This rule is not a significant regulatory action and was therefore not submitted to the Office of Management and Budget (OMB) for interagency review under this E.O.

B. Paperwork Reduction Act

This action does not impose an information collection burden under the Paperwork Reduction Act. This rule does not impose any information collection, reporting, or recordkeeping requirements. This proposal would merely add or revise CWA test procedures.

C. Regulatory Flexibility Act

I certify that this action would not have a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act. This action will not impose any requirements on small entities. This action would approve new and revised versions of CWA testing procedures. Generally, these changes would have a positive impact on small entities by increasing method flexibility, thereby allowing entities to reduce costs by choosing more cost-effective methods. In general, the EPA expects the proposed revisions would lead to few, if any, increased costs. As explained previously, most of the proposed changes clarify or improve the instructions in the method, update the technology used in the method, improve the QC instructions, make editorial corrections, or reflect the most recent approval year of an already approved method. In some cases, the proposal would add alternatives to currently approved methods for a particular analyte (e.g., Method N07-0003 for Nitrate Reductase Nitrate-Nitrogen Analysis). Because these methods would be alternatives rather than requirements, there are no direct costs associated with this proposal. The EPA proposes methods that would be incorporated by reference. If a permittee elected to use these methods, they could incur a small cost associated with obtaining these methods from the listed sources. See Section IV.B.

D. Unfunded Mandates Reform Act

This action does not contain any unfunded mandate as described in the Unfunded Mandates Reform Act, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. The action imposes no enforceable duty on any state, local or tribal governments or the private sector.

E. Executive Order 13132: Federalism

This proposed rule does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

This proposed rule does not have tribal implications as specified in Executive Order 13175. This rule would merely approve new and revised versions of test procedures. The EPA does not expect the proposal would lead to any costs to any tribal governments, and if incurred, projects they would be minimal. Thus, Executive Order 13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

The EPA interprets Executive Order 13045 as applying only to those regulatory actions that concern environmental health or safety risks that the EPA has reason to believe may disproportionately affect children, per the definition of “covered regulatory action” in section 2-202 of the Executive Order. This action is not subject to Executive Order 13045 because it does not concern an environmental health risk or safety risk.

H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution, or Use

This action is not subject to Executive Order 13211 because it is not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act of 1995

This action involves technical standards. The EPA proposes to approve the use of technical standards developed and recommended by the Standard Methods Committee and ASTM International for use in compliance monitoring where the EPA determined that those standards meet the needs of CWA programs. As described above, this proposal is consistent with the NTTAA.

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations

The EPA believes the human health or environmental risk addressed by this action will not have potential disproportionately high and adverse human health or environmental effects on minority, low-income or indigenous populations.

List of Subjects in 40 CFR Part 136

• Environmental protection
• Incorporation by reference
• Reporting and recordkeeping requirements
• Test procedures
• Water pollution control

For the reasons set out in the preamble, title 40, chapter I of the Code of Federal Regulations is proposed to be amended as follows:

PART 136—GUIDELINES ESTABLISHING TEST PROCEDURES FOR THE ANALYSIS OF POLLUTANTS

1. The authority citation for part 136 continues to read as follows:

Authority: Secs. 301, 304(h), 307 and 501(a), Pub. L. 95-217, 91 Stat. 1566, et seq. (33 U.S.C. 1251, et seq.) (the Federal Water Pollution Control Act Amendments of 1972 as amended by the Clean Water Act of 1977).

2. Amend § 136.3 by:

a. In paragraph (a), seventh sentence, removing the word “year” and adding in its place the word “date” in its place, and removing from the last sentence the text “(paragraph (c) of this section, in § 136.5(a) through (d) or 40 CFR 401.13)” and adding in its place the text “paragraph (c) of this section, § 136.5(a) through (d) or 40 CFR 401.13,” respectively;

b. Revising tables IA, IB, IC, and IH;

c. Revising paragraph (b) by:

i. Revising the introductory text; paragraph (b)(8) introductory text, and paragraphs (b)(8)(ix) through (b)(xv);

ii. Adding paragraph (b)(8)(xvi);

iii. Revising paragraphs (b)(10)(xiv), (b)(10)(xxxix), (b)(10)(xliv), (b)(10)(xlvi), (b)(10)(lii), (b)(10)(liv), (b)(10)(lxvii), (b)(10)(lxviii), (b)(10)(lxix), (b)(10)(lxx), b)(15)(v), (b)(15)(vi), (b)(15)(viii) through (xiii), (b)(15)(xv) through (xix), (b)(15)(xxi) through (xxvi), (b)(15)(xxxi), (b)(15)(xxxiv) and (xxxv), (b)(15)(xxxvii), (b)(15)(xxxix) through (xliii), (b)(15)(xlv) through (l), (b)(15)(lii), (b)(15)(liv) and (b)(15)(lv), (b)(15)(lviii), (b)(15)(lxi) through (lxvi), and (b)(15)(lxviii) through (lxix); and

iv. Adding paragraph (b)(15)(lxx);

v. Redesignating paragraphs (b)(25) through (b)(36) as paragraphs (b)(28) through (b)(39);

vi. Redesignating paragraphs (b)(19) through (24) as paragraphs (b)(20) through (25);

vii. Adding new paragraphs (b)(19), (26), and (27); and

viii. Revising the newly redesignated paragraphs (b)(38)(ii) through (xxi);

ix. Adding paragraphs (b)(38)(xxii) and (xxiii); and

c. Revising paragraph (e) Table II.

The revisions and additions read as follows:

3. Amend § 136.6 by adding paragraph (b)(4)(xxiii) to read as follows:

Footnotes