Upgrades/Improvements to EPA Methods 624 and 625 Included in the docket for the 2014 Methods Update Rule proposal is a copy of the following presentation on “Upgrades/Improvements to EPA Methods 624 and 625” given by EPA at the 2014 National Environmental Monitoring Conference (NEMC) in Washington, DC, in August 2014. The presentation provides an overview of revisions made to these methods as a result of several rounds of internal and external reviews between 2012 and 2014. Reviews were performed by :
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• • • • • • EPA’s Office of Research and Development (ORD) , EPA’s Office of Enforcement and Compliance Assurance (OECA) , EPA’s Office of Solid Waste and Emergency Response (OSWER) , EPA and state regulatory/control personnel, EPA’s L aboratory Technical Information Group (LTIG), the Independent Laboratories Institute (ILI) of the American Council of Independent Laboratories (ACIL) , EPA laboratory personnel, Commercial laboratory personnel, Instrument vendors, Independent consultants, the Environmental Laboratory Advisory Board (ELAB) including members of industry, and P articipants at several EPA workshops. EPA believes that the revisions made as a result of these reviews represent a significant improvement in these methods, and form the basis for soliciting comments from stakeholders as part of the promulgation process. As part of its proposal, EPA seeks comments on the revised methods.Office of Water 

# Upgrades/Improvements to EPA Methods 624 and 625 Lem Walker Engineering and Analysis Division Office of Science and TechnologyOffice of Water 

# Method 624 and 625 Revisions

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### Methods 624 and 625 were revised to 624.1 and 625.1 with stakeholder input between June 2012 and June 2014. Interim drafts of each method were circulated for comment in:

• • June 2012, with comments accepted through December 2012 June 2013, with comments accepted through August 2013 

### Methods 624.1 and 625.1 are in near final form at present, and stakeholder comments will be solicited shortly. EPA expects to propose Methods 624.1 and 625.1 in the upcoming Met hods Update Rule, and public comments on the revised methods are expected in response to the proposalOffice of Water 

# Methods 624.1 & 625.1 – Analytes of Interest

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### Methods 624.1 and 625.1 focus on “analytes of interest”

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### Analytes of interest are those required to be determined by a regulatory/control authority, in a permit, or for a client Quality control (QC) tests must be performed, and QC acceptance c r iteria must be met, for the analytes of interest If analytes of interest are not specified to the laboratory by the r egul atory/control authority, by a permit, or by a client:

• • The analytes in Table 1 of 624.1 must be determined The analytes in Table 1 (base/neutrals) and Table 2 (acids) of 625.1 must be det ermined
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### EPA “priority pollutants” (40 CFR 423, appendix A) are identified in the tablesOffice of Water 

# 624.1/625.1 – Discharge - specific Spiking

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• Moved responsibility for identifying samples to be spiked from lab to the dis charger. Each specific discharge must be spiked at a frequency no less than 5 percent (1 in every 20 samples)

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• Requirement negotiated with industry when 600 - Series methods were developed Assures applicability to each specific discharge 

### Requirement made more explicit in 624.1 and 625.1, including preparation of an MS/MSD pair to allow assessment of precision in the sample matrix Spike concentration should be at:
• • • • Regulatory compliance limit, 1- 5 times the background concentration in the sample, Near the mid - point of the calibration range, or Concentration in the laboratory control sample, whichever is greaterOffice of Water 

# 624.1/625.1 – Miscellaneous Changes

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### Require reporting of results for the blank and sample separately. Allow reporting a blank - subt racted result only if required by a regulatory/control authority or in a permit. Provide procedures for dilution of a sample or sample extract when a pol lutant concentration exceeds the calibration range Provide suggestions for analysis of complex samples Allow reporting of problems with results when QC tests are failed repeat edlyOffice of Water 

# 624.1/625.1 Reporting Levels

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### Methods 624 and 625 were promulgated in 1984 and did not specify reporting levels Methods 624.1 and 625.1 require reporting to the Minimum Level of Q uantitation (ML)Office of Water 

# 624.1/625.1 RSD of RF

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### Relative standard deviation (RSD) of response factor (RF) is used as a breakpoint between the allowed use of an average RF that models a straight line through the origin, and the required use of a calibration curve (a straight line not through the origin or quadratic)

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### Full scan GC/MS methods promulgated in 1984 (624, 625, 1624, 1625) , and other CWA GC/MS methods use <35% as the breakpoint

• • <35% is based results of the interlaboratory study of Method 1625 <35% was set based on an overall failure rate of <5% when a large num ber of analytes are tested simultaneouslyOffice of Water 

# 624.1/625.1 QC Acceptance Criteria

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## QC acceptance criteria are listed in Table 7 of 624.1 and in Table 6 of 625.1

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## Criteria in these tables were developed in the early 1980s Stakeholders stated that QC acceptance criteria were t oo broadOffice of Water 

# 624.1/625.1 QC Acceptance Criteria Continued

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### For Methods 624.1 and 625.1, EPA will require development of “in - house” QC acceptance criteria by each lab

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### Separate in - house QC acceptance criteria for the LCS and for the MS/MSD, for each analyte and surrogate, must be established as:

• • the mean recovery ± 3 standard deviations, and the m ean RPD + 3 standard deviations 

### Criteria must be based on analysis of a minimum of 20 samples; interim criteria of 60 – 140% recovery and 30% RPD must be used until 20 results are obtained. At least 80% of QC acceptance criteria must be tighter than the c riteria in the tables in the methods. If an in - house criterion is not tighter, the limit in the table must be used.Office of Water 

# 624.1/625.1 Nationwide Method Modifications

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### For Methods 624.1 and 625.1, EPA will allow a discharger and/or laboratory to modify a method for nationwide use, provided that:

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### all QC tests were run, all QC acceptance criteria were met with the modification as an i ntegral part of the method, the modified method is tested by spiking a minimum of nine (9) di fferent discharges in duplicate (MS/MSD) and meeting the QC acceptance criteria for the MS/MSD 

### An example of a modification would be the use of solid - phase extraction (SPE) in Method 625.1. Characteristics of the nine discharges are given on the next slideOffice of Water 

## Characteristics of Discharges Tested when Modifying a Method

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### Effluent from a Publicly Owned Treatment Works (POTW) ASTM D 5905, Standard Specification for Substitute Wastewater Sewage sludge, if sewage sludge will be in the permit ASTM D 1141, Standard Specification for Ocean Water, if ocean w ater will be in the permit A proficiency testing (PT) sample from a recognized provider Untreated and treated wastewaters from a minimum of 9 matrix t ypes, as defined in the alternate test procedure (ATP) protocolOffice of Water 

## Characteristics of Discharges Tested when Modifying a Method (cont.)

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### At least one of the nine matrix types must have at least one of the following characteristics:

• • • • • TSS >40 mg/L TDS >100 mg/L Oil & grease >20 mg/L NaCl > 120 mg/L CaCO 3 >140 mg/LOffice of Water 

## Revised ATP and New Method Protocols for Chemical Methods for use in Wastewater

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### Current protocols were published in 1999:

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• Protocol for EPA Approval of Alternate Test Procedures for Organic and Inorganic Analytes in Wastewater and Drinking Water, March 1999 Protocol for EPA Approval of New Methods for Organic and Inorganic Analytes i n Wastewater and Drinking Water, March 1999 

### These protocols introduced a three - tiered validation system based on the intended use of the method •

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• Tier 1 – Limited use in one or more laboratories, in one or more matrix types (approved by Regional ATP Coordinator) Tier 2 – N ationwide use in all laboratories, in a single matrix type (approved through rulemaking) Tier 3 – Nationwide use in all laboratories, in all matrix types (approved through rulemaking)Office of Water 

## Revised ATP and New Method Protocols for Chemical Methods for use in Wastewater (cont.)

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### The protocols have been revised to:

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• Focus only on methods intended for use in wastewater compliance monitoring Include procedures for validation of methods that measure method - def ined parameters Provide updated contact information for National and Regional ATP C oordinators Clarify that methods developed by VCSBs do not fall within the scope of the al ternate test procedure program and have a separate path for review and potential approval Clarify that for limited - us e ATPs, the approval may be restricted to use only with respect to a specific discharge or facility (and its laboratory) or, at the discretion of the Regional ATP Coordinator, to all dischargers or facilities (and their associated laboratories) specified in the approval for the RegionOffice of Water 

# Questions or Comments Lemuel (Lem) Walker, Jr. Office of Science and Technology Engineering and Analysis Division (EAD) walker.lemuel@epa.gov http://www.epa.gov/waterscience/methods Methods Questions? Write to:

OSTCWAMethods@epa.gov