UCMR 4 Laboratory 

Approval Requirements 

and Information 

Document

Version 1.0

November 2015

Technical Support Center

Standards and Risk Management Division

Office of Ground Water and Drinking Water

U.S. Environmental Protection Agency

Cincinnati, OH 45268

Laboratory Manager: ________________________________ Date:___________

This signature affirms that the Laboratory Manager

and the staff who are anticipated to participate in UCMR 4

have read the UCMR 4 Laboratory Approval Requirements and Information Document.
i

Office of Water (4607 M)

EPA 815-B-15-004

November 2015
ii

Foreword

The proposed Revisions to the Unregulated Contaminant Monitoring Rule (UCMR 4) for Public Water 

Systems require public water systems (PWSs) to collect specific data and information during a defined 

monitoring period. The UCMR rule also establishes requirements and specifications for the reporting of 

UCMR 4 data to the United States Environmental Protection Agency (EPA). This document, the UCMR 4 

Laboratory Approval Requirements and Information Document, serves as a support document for 

laboratories interested in becoming EPA approved and maintaining their EPA approval to analyze 

samples collected at PWSs to meet the future UCMR 4 requirements for contaminants. The main 

objective of this document, the UCMR 4 Laboratory Approval Requirements and Information Document, 

is to provide laboratories with detailed information on the UCMR 4 laboratory approval process. The 

document is intended to describe the proposed:

• laboratory approval process,

• procedures that EPA uses to assess a laboratory's ability to produce data of known and acceptable 

accuracy and precision, 

• sample collection and handling requirements,

• laboratory data quality control requirements for UCMR 4 chemical analyses, and

• specific analytical procedures for UCMR 4.

Laboratories will be required to follow this UCMR 4 Laboratory Approval Requirements and Information 

Document to process UCMR 4 samples collected at PWSs and maintain their status as an EPA approved 

UCMR 4 laboratory. This document was prepared by EPA’s Office of Ground Water and Drinking Water 

(OGWDW), Standards and Risk Management Division (SRMD), Technical Support Center (TSC), 

Cincinnati, Ohio 45268. Additional information on the UCMR program can be found at the UCMR 

Homepage.

This manual was prepared as supporting documentation to launch the UCMR 4 Laboratory Approval 

Program based upon the proposed UCMR 4. This document will be updated as Version 2.0, once the 

UCMR 4 final rule is published. Any references within this document to “approved” methods or program 

“requirements” are conditional and subject to change with the promulgation of the UCMR 4 final rule. 

Disclaimers

1. Mention of trade names or commercial products does not constitute endorsement or 

recommendation for use.

2. This document describes the provisions of the proposed UCMR 4 program, the analytical 

methods for UCMR 4 contaminants, and EPA regulations that once final, establish legally binding 

requirements. However, this document does not substitute for those future provisions or regulations.

3. Laboratory approval to perform UCMR 4 analyses will only apply during UCMR 4 monitoring. If 

new drinking water regulations are promulgated using similar analyses and the same methods, 

laboratories will then be required to be certified through the process appropriate to their primacy 

agent, that is, their State or EPA Region.

4. The UCMR 4 laboratory approval process is not related to the laboratory certification process for 

conducting compliance monitoring under other National Primary Drinking Water Regulations (NPDWRs). 

A laboratory’s approval for UCMR 4 analyses has no impact on their certification to perform compliance 

monitoring under other NPDWRs.
iii

Abbreviations

ADDA (all-S,all-E)-3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic 

acid

APHA American Public Health Association

ASTM ASTM International

AWWA American Water Works Association

C8 Octyl-functionalized silica gel

C18 Octadecyl-functionalized silica gel

CAS Chemical Abstract Service

CCC Continuing calibration check

CFR Code of Federal Regulations

ELISA Enzyme-linked immunosorbent assay

EPA United States Environmental Protection Agency

GC-MS Gas chromatography/mass spectrometry

HRPIR Half range for the prediction interval of results

IC Ion chromatography

ICP-MS Inductively coupled plasma mass spectrometer

ID Identification

IDA Initial demonstration of accuracy

IDC Initial demonstration of capability

IDP Initial demonstration of precision

IG EPA Inspector General

LAP Laboratory Approval Program

LCMRL Lowest concentration minimum reporting level

LC-ESI-MS-MS Liquid chromatography electrospray ionization tandem mass spectrometry

LC-MS-MS Liquid chromatography tandem mass spectrometry

LFB Laboratory fortified blank

LFSM Laboratory fortified sample matrix

LFSMD Laboratory fortified sample matrix duplicate

LRB Laboratory reagent blank

MRL Minimum reporting level

m/z Mass-to-charge ratio

NA Not applicable

NERL National Exposure Research Laboratory

NPDWR National Primary Drinking Water Regulation

OGWDW Office of Ground Water and Drinking Water

ORD Office of Research and Development

PIR Prediction interval of results

PIRLower Lower PIR limit

PIRUpper Upper PIR limit

PT Proficiency testing

PWS Public water system

QA Quality assurance

QAPP Quality Assurance Project Plan

QC Quality control
iv

Abbreviations

QCS Quality control sample

QMP Quality Management Plan

RPD Relative percent difference

RSD Relative standard deviation

s Standard deviation

SDVB Styrene divinylbenzene

SDWA Safe Drinking Water Act

SDWARS Safe Drinking Water Accession and Review System

SIM Selective ion monitoring

SM Standard Methods for the Examination of Water and Wastewater

SOP Standard operating procedure

SPE Solid phase extraction

SRMD Standards and Risk Management Division

Tris tris(hydroxymethyl)aminomethane

TSC Technical Support Center

UCMR Unregulated Contaminant Monitoring Rule

UCMR 1 First Unregulated Contaminant Monitoring Rule

UCMR 2 Second Unregulated Contaminant Monitoring Rule

UCMR 3 Third Unregulated Contaminant Monitoring Rule

UCMR 4 Fourth Unregulated Contaminant Monitoring Rule

UPLC Ultra performance liquid chromatography

v:v Volume-to-volume

WEF Water Environment Federation
v

Table of Contents

Foreword....................................................................................................................................................... ii

Disclaimers.................................................................................................................................................... ii

Abbreviations............................................................................................................................................... iii

1 Introduction ..........................................................................................................................................1

1.1 Background on the Unregulated Contaminant Monitoring Rule..................................................1

1.2 Ensuring Data Quality for UCMR 4................................................................................................1

2 UCMR 4 Laboratory Approval Process..................................................................................................1

2.1 Registration for the UCMR 4 Laboratory Approval Program........................................................2

2.2 UCMR 4 LAP Applications..............................................................................................................2

2.3 EPA Review of Submitted Application Material............................................................................3

2.4 UCMR 4 Proficiency Testing..........................................................................................................3

2.5 Procedure for Revocation of UCMR Approval Status...................................................................4

3 Laboratory Quality Management Plan and UCMR 4 Quality Assurance Project Plan ..........................4

3.1 Quality Management Plan for UCMR 4.........................................................................................5

3.2 Quality Assurance Project Plan for UCMR 4 .................................................................................6

4 Methods for UCMR 4 Monitoring .........................................................................................................7

4.1 EPA Method 200.8 Rev. 5.4, ASTM Method D5673-10, SM 3125B (Referred to as EPA 200.8)...7

4.2 EPA ELISA Method.........................................................................................................................8

4.3 EPA Method 525.3 ........................................................................................................................8

4.4 EPA Method 530 ...........................................................................................................................8

4.5 EPA Method 541 ...........................................................................................................................9

4.6 EPA Method 544 ...........................................................................................................................9

4.7 EPA Method 545 ...........................................................................................................................9

4.8 EPA Method 557 .........................................................................................................................10

4.9 Table 1: UCMR 4 Chemical Analytes and Methods: Assessment Monitoring. ...........................10

5 Initial Demonstration of Capability for UCMR 4 Analyses..................................................................11

5.1 Submission of IDC Data...............................................................................................................11

5.2 IDC Study Elements.....................................................................................................................12

5.3 Table 2: IDC Quality Control Requirements for MRL Verification and for Precision and Accuracy

12

6 Minimum Reporting Level Verification...............................................................................................13

6.1 Fortify, Process, and Analyze Seven Replicate LFBs at or Below Proposed MRL........................13
vi

6.2 Calculate the mean and standard deviation...............................................................................13

6.3 Half range for the prediction interval of results.........................................................................13

6.4 Confirm PIR limits are within QC criteria ....................................................................................13

6.5 Example Calculation of the PIR limits .........................................................................................14

7 Quality Control Requirements............................................................................................................14

7.1 Extraction Batch and Digestion Batch.........................................................................................14

7.2 Analysis Batch .............................................................................................................................15

7.3 Initial Calibration of Analytical Instruments ...............................................................................15

7.4 Continuing Calibration Checks (CCCs).........................................................................................17

7.5 Surrogate Requirements and Criteria.........................................................................................18

7.6 Internal Standard Requirements and Criteria.............................................................................20

7.7 Laboratory Reagent Blank...........................................................................................................21

7.8 Laboratory Fortified Blank (LFB) .................................................................................................23

7.9 Quality Control Sample (QCS).....................................................................................................24

7.10 Laboratory Fortified Sample Matrix & Laboratory Fortified Sample Matrix Duplicate ..............25

7.11 Sequence of Injection for Analysis Batch....................................................................................26

7.12 Exceeding the Calibration Range ................................................................................................27

7.13 Legal Defensibility of Data ..........................................................................................................28

8 Sample Handling Requirements..........................................................................................................28

8.1 Sample Collection Time and Date...............................................................................................28

8.2 Sample Transport and Storage....................................................................................................29

8.3 Sample Preservation ...................................................................................................................30

8.4 Extract Holding Times and Temperatures...................................................................................32

8.5 Invalid Sample.............................................................................................................................32

8.6 Method Information Concerning Collection and Holding ..........................................................32

8.7 Sample Volume ...........................................................................................................................33

8.8 Laboratory Errors or Sampling Deviations..................................................................................33

9 Uploading Data to EPA database ........................................................................................................33

9.1 Table 14. Unregulated Contaminant Monitoring Reporting Requirements...............................33

9.2 HAAs Reported as Groups...........................................................................................................33

10 References ......................................................................................................................................38

11 Appendix A: Requirements for Water Quality Parameters and Indicators ....................................39

11.1 Total Organic Carbon (TOC) and Bromide ..................................................................................39
vii

11.2 Temperature and pH Data for ELISA method .............................................................................39

12 Appendix B: Requirements for UCMR 4 Method 200.8 Analysis....................................................40

12.1 Isotopes and Internal Standards.................................................................................................40

12.2 Additions and Exceptions to Method 200.8 for UCMR 4............................................................40

12.3 Table 16. Determination of Metals for UCMR 4 by EPA Method 200.8 Rev. 5.4 .......................41

13 Appendix C: LCMRLs and MRLs for UCMR 4 Target Analytes.........................................................41

13.1 Table 17: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 200.8 (SIM)........................41

13.2 Table 18: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 525.3 (SIM)........................41

13.3 Table 19: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 530. ...................................41

13.4 Table 20: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 541. ...................................42

13.5 Table 21: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 544. ...................................42

13.6 Table 22: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 545. ...................................42

13.7 Table 23: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 552.3. ................................42
1

1 Introduction

1.1 Background on the Unregulated Contaminant Monitoring Rule

The Safe Drinking Water Act (SDWA), as amended in 1996, requires EPA to establish criteria for a 

program to monitor unregulated contaminants and to publish a list of contaminants to be monitored 

every five years. In fulfillment of this requirement, EPA published the contaminant lists for the first, 

second, and third UCMRs, that is, UCMR 1, UCMR 2, UCMR 3, respectively, in the Federal Register in 

September 1999, January 2007, and May 2012. The UCMR program uses a three-tiered approach for 

monitoring contaminants that takes into account the availability of analytical methods, the source water 

supply and the contaminants likely to be found. UCMR 4 monitoring period is scheduled to occur from 

January 2018 through December 2020. EPA identified thirty chemical contaminants for UCMR 4. 

Monitoring for these contaminants is supported by eleven analytical methods.

1.2 Ensuring Data Quality for UCMR 4

Data reported under UCMR 4 must meet specific precision and accuracy targets to achieve the 

objectives of the program. During UCMR 4 development, EPA established criteria to ensure that data 

generated during the monitoring period are of high quality. Maintaining data comparability among 

laboratories is essential, and will allow the data to be used in statistical analyses to reliably predict the 

national occurrence of the contaminants in drinking water. EPA ensures the integrity of the data by: 1) 

defining and maintaining strict requirements for sample collection, sample handling, processing and 

analysis, and data reporting, and 2) assisting the drinking water industry in identifying qualified 

laboratories that can accurately and reliably perform the analyses required by UCMR 4.

1.2.1 Laboratory Approval Approach

The laboratory approval process described in this document ensures that analytical data generated for 

the UCMR are of adequate quality. EPA used a similar laboratory approval approach in previous UCMRs 

and believes this process is effective in yielding high quality data. An overview of the Laboratory 

Approval Program (LAP) and its requirements for UCMR 4 is presented in this UCMR 4 Laboratory 

Approval Requirements and Information Document, including:

• a description of the UCMR 4 laboratory approval process;

• a discussion of the required quality assurance (QA) documentation that must be prepared and 

followed at EPA-approved UCMR 4 laboratories;

• a summary of the UCMR 4 contaminant analytical methods, minimum reporting levels (MRLs), and 

initial demonstration of capability (IDC) requirements; and

• a summary of the laboratory data quality control (QC) requirements for UCMR 4 analyses.

Laboratories must follow the procedures outlined in this document to obtain approval for the analysis of 

UCMR 4 samples.

2 UCMR 4 Laboratory Approval Process

Laboratories analyzing samples for UCMR 4 contaminants in Table 1 must follow the process outlined in 

this section to obtain approval. Approval is by method and by individual laboratory location. A 

laboratory may apply for approval for any number of UCMR 4 methods. If a laboratory organization has 

multiple locations, each laboratory location must complete the process independently. Water systems 
2

analyzing samples for bromide or total organic carbon must follow the process outlined in in Section 

11.1, Appendix A.

2.1 Registration for the UCMR 4 Laboratory Approval Program

Laboratories interested in UCMR 4 laboratory approval are to contact EPA as soon as possible. 

Laboratories must request UCMR 4 registration within 120 days of publication of the Final UCMR 4. 

Laboratories should send a letter of interest with contact information, including an e-mail address, to 

the following address:

UCMR Laboratory Approval Coordinator

U.S. Environmental Protection Agency

Technical Support Center

26 West Martin Luther King Drive (MS 140)

Cincinnati, OH 45268

or use the e-mail address: UCMR_Sampling_Coordinator@epa.gov.

Upon receipt of correspondence from a laboratory indicating their interest in participating in the UCMR

4 LAP, EPA will e-mail UCMR 4 registration information to the laboratory.

2.1.1 Completing the UCMR 4 Registration Sheet

The laboratory must complete the UCMR 4 registration sheet, indicating the UCMR 4 chemistry methods 

for which they are seeking approval, and promptly return it to EPA at the above e-mail address. EPA will 

issue a UCMR-specific laboratory ID to each participating laboratory. Registration information should be 

received by EPA no later than 30 days after receiving the registration materials from EPA.

2.2 UCMR 4 LAP Applications

EPA will forward the appropriate application packet to the laboratory based on the information 

provided on the registration sheet. The application packet will include a general application, and a 

method-specific application for each method selected on the registration sheet. Completed applications 

are to be returned to EPA as soon as possible for review. Firm application deadlines are established with 

each proficiency testing study (Section 2.4). EPA will acknowledge receipt of application materials in 

correspondence to the laboratory. To complete these applications, laboratories must take the following 

six steps shown in Sections 2.2.1 to 2.2.6.

2.2.1 Drinking Water Certification

Document drinking water certification by a state or regional Certification Authority for the analysis of 

samples using gas chromatography, liquid chromatography, ion chromatography, or inductively coupled 

plasma mass spectrometry methods, as indicated in the applications. Certification is not required in the 

specific technique used in the method for which the laboratory is seeking approval. However,

certification in a minimum of one drinking water method is required.

2.2.2 Personnel Information

Provide information about the personnel who will be involved in UCMR 4 work.

2.2.3 Provide QA Information

Provide QA information, including a copy of the table of contents from the laboratory’s Quality 

Management Plan (QMP), (Section 3.1).
3

2.2.4 Analytical Equipment and Sample Handling Procedures

Provide information regarding analytical equipment and sample handling procedures.

2.2.5 Data Submission

For each method for which the laboratory is seeking approval, submit data from: 1) an IDC study 

(Section 5); 2) analysis of laboratory reagent blank (LRB) samples (Section 7.7); and 3) analysis of a set of 

laboratory fortified sample matrix (LFSM), LFSM duplicate (LFSMD), and the corresponding unfortified 

drinking water sample (Section 7.10). Data submitted must include labeled chromatograms or 

spectrometric traces, include quantitation reports with surrogate recovery results and internal standard 

response results.

2.2.6 EPA Electronic Reporting System

Document that the laboratory will post UCMR 4 results to the EPA’s electronic data reporting system, 

accessible at the UCMR Homepage (Section 9). Laboratories must report field sample results and 

associated QC data, as required by the EPA electronic data reporting system, within 120 days from the 

sample collection date. Failure to post data to the EPA electronic data reporting system will result in EPA 

revoking the laboratory’s approval status. Once approval is revoked, the laboratory cannot be 

reapproved during the UCMR 4 monitoring period.

2.3 EPA Review of Submitted Application Material

EPA will review the submitted application materials. If deficiencies are identified in the application 

materials, EPA will identify the areas of deficiency and necessary corrective actions to be taken in a 

report to the laboratory. Laboratories who receive a deficiency report will have the opportunity to make 

corrective actions and submit new application information. If all requested information is present and 

acceptable, EPA will notify the laboratory that they are eligible to participate in a UCMR 4 proficiency 

testing (PT) study. EPA anticipates the UCMR 4 LAP application period for UCMR 4 will close in mid-2017 

with the application submission deadline for the final PT study.

2.4 UCMR 4 Proficiency Testing

EPA will conduct at least two PT studies prior to publication of the UCMR 4 final rule and intends to offer 

a minimum of three PT studies prior to closing the Laboratory Approval Program. Each laboratory must 

pass one PT study for each method for which they are seeking approval. When the laboratory’s 

application for a specific method is reviewed and determined to meet the UCMR 4 method criteria, that 

laboratory can participate in EPA’s UCMR 4 PT study for that method. Participation in a PT study is 

method-specific. A laboratory is not required to concurrently participate in a PT study for all methods for 

which they are seeking approval.

2.4.1 Method Specific PT

EPA will send a method-specific PT ampule to participating laboratories, with instructions and a cover 

letter specifying a due date for reporting results to EPA. The laboratory will always have a minimum of 

two weeks to perform the analysis. Laboratories should not assume that all UCMR 4 analytes for a 

method will be present in a PT ampule for that method. Laboratories that do not pass the PT study for a 

given method can participate in the next PT study for that method, if one is scheduled. However, 

laboratories that have passed a PT study for a given method will not receive additional PT samples for 

that method during subsequent UCMR 4 PT studies.

2.4.2 Successful Completion of Method Specific PT Study

Upon successful participation in a PT study for a specific method, the laboratory will be notified in 

writing that it has met the initial approval criteria for each method. Laboratories that passed a PT study 
4

prior to publication of the UCMR 4 final rule will be granted a “Pending Approval” for UCMR 4, 

contingent upon: 1) changes applied to the final rule as a result of public comments to the proposed 

rule, and 2) resolution of any findings resulting in a laboratory audit. Laboratories are not authorized to 

analyze UCMR 4 monitoring samples until they receive formal “Final Approval” in writing from EPA. EPA 

will not accept analytical results for UCMR 4 samples collected prior to the monitoring date specified in 

the final UCMR 4.

2.5 Procedure for Revocation of UCMR Approval Status

EPA may consider revoking UCMR approval status for several reasons. Once approval is revoked, the 

laboratory cannot be reapproved during the UCMR 4 monitoring period. When revocation is deemed 

necessary, approval will be revoked in writing, via a letter from EPA, stating the reasons for EPA’s 

decision. Laboratories receiving such notice are to stop analyzing samples as of the effective date 

specified in the letter.

2.5.1 Reasons for Revocation of Approval

Laboratories reporting invalid data are subject to revocation of UCMR 4 laboratory approval, depending 

on the frequency or severity of the data validity issue. Laboratories that do not report data in a 

complete, timely manner are likewise subject to revocation of approval, depending on the frequency or 

severity of the reporting delay. Laboratories must report field sample results and associated QC data, 

following the instructions for the EPA electronic data reporting system, within 120 days from the sample 

collection date, as required by the rule. 

2.5.2 Fraudulently Reporting Data

Laboratories suspected of reporting fraudulent data will not only risk revocation of their UCMR 4 

laboratory approval status but may also be subject to investigation by the EPA Inspector General (IG). An

IG determination of lab fraud may preclude the laboratory from participating in future UCMR 

monitoring programs.

2.5.3 Deviating from Method Procedures

An EPA approved UCMR 4 laboratory must follow the UCMR 4 analytical methods and the specifications 

found throughout this manual to maintain their status as an EPA-approved UCMR laboratory. When a 

method includes flexibility options, the laboratory may consider these options but any procedural 

modifications within the scope of the method-defined flexibility must be clearly identified in the 

appropriate sections of the laboratory’s UCMR 4 method application. Laboratories must perform the 

method as identified in their UCMR 4 method application, or must request and receive EPA 

authorization to substantively modify those application details during active implementation of UCMR 4. 

To avoid jeopardizing their approval, laboratories are encouraged to seek early clarification from EPA 

regarding any matter involving method modifications.

3 Laboratory Quality Management Plan and UCMR 4 Quality Assurance 

Project Plan

A Quality Management Plan (QMP) is a document that describes the general practices of an organization 

or program. The QMP may be viewed as the "umbrella" document under which individual projects are 

conducted. More information regarding laboratory QMPs can be found in EPA Requirements for Quality 

Management Plans (QA/R-2).

A Quality Assurance Project Plan (QAPP) documents details specific to an individual project within the 

organization or program.
5

3.1 Quality Management Plan for UCMR 4

Laboratories analyzing samples for UCMR 4 are required to adhere to defined QA and QC procedures. 

This ensures that analytical data generated for UCMR 4 are scientifically valid and are of known and 

acceptable precision and accuracy. Each laboratory must have a written description of its QA activities 

detailed in a QMP, which describes the QA management of day-to-day routine operations. A QMP 

documents how an organization will plan, implement, and assess the effectiveness of its QA and QC 

operations. The QMP is a tool to help the laboratory maintain and improve data dependability and 

quality. Specifically, it describes how an organization structures their quality system, including: quality 

policies and procedures; areas of application; and roles, responsibilities, and authorities. The QMP must 

be kept current during the time the laboratory is performing UCMR 4 measurements. Laboratories are 

required to submit a copy of the Table of Contents from their QMP to EPA as part of the UCMR 4 LAP 

(Section 2.2). The laboratory QMP should be concise and, at a minimum, address the following topics in 

Sections 3.1.1 through 3.1.5.

3.1.1 QMP References

Certain sections of the laboratory QMP can reference existing documented procedures, such as the 

laboratory's standard operating procedures (SOPs), EPA analytical methods, or other literature, such as 

Standard Methods for the Examination of Water and Wastewater.

3.1.2 Laboratory organization and responsibility

• The laboratory’s organizational chart showing lines of authority, including QA Managers;

• A list of key individuals responsible for producing valid measurements and conducting routine 

assessments of QC procedures and measurements;

• Identification of the person responsible for internal audits and reviews of the implementation of 

the QMP and its requirements;

• A description of laboratory training to keep personnel current on regulations and methods; and

• Documentation of ethics training.

3.1.3 Field sampling

• Personnel responsible for collecting samples; and

• Procedures for sample collection, preservation, containment, holding times, and transport to the 

laboratory.

3.1.4 Laboratory sample handling procedures

• Procedures for sample receipt, including criteria for the rejection of samples that do not meet 

shipping, holding time and/or preservation requirements;

• Bench sheets used upon sample receipt, during processing, extraction, and digestion of samples, 

and during analysis of samples, extracts or digestates;

• Storage requirements for samples, extracts, and digestates, including criteria for temperature and 

holding times; and

• Sample tracking used to maintain the integrity of all samples from receipt by the laboratory 

through analysis and reporting to disposal.

3.1.5 Chemical, reagent and standard control procedures

• Procedures for preparation, labeling, documentation and storage of reagents, chemicals, 

calibration standards, surrogate standards, internal standards; and
6

• Frequency of initial calibration, continuing calibration checks (CCCs), and validation of calibrations.

3.1.6 Analytical procedures

• Reference methods and corresponding SOP numbers/names used for each type of analysis;

• Location of SOPs;

• Frequency of SOP review;

• Analytical instrument identification/labeling; and

• Identification of which analytical instruments are used for each type of analysis.

3.1.7 Data reduction, verification, validation and reporting

• Process for converting raw data to reportable concentrations;

• Process for ensuring the accuracy of data transcription and calculations;

• Process for validating data;

• Process and format for reporting results to clients; and

• Procedure used for data corrections.

3.1.8 QC Procedures

• Types and frequency of QC sample analysis;

• MRL verification procedures, criteria and frequency;

• Use and criteria for internal and surrogate standards; and

• Procedures for IDCs, and preparation of control charts.

3.1.9 Preventive maintenance

• Equipment manual location and availability;

• Spare parts inventory; and

• Schedule and procedures for, and documentation of, preventative maintenance.

3.1.10 Corrective action

• Response to obtaining unacceptable results from the analysis of PT samples or internal QC checks;

• Identification of the person(s) responsible for determining that corrective action is necessary, and 

ensuring that it is completed; and

• Procedure for documenting actions taken and their effectiveness.

3.1.11 Record Keeping

• Procedure for maintaining records, including duration and location;

• Procedure for backing-up databases and electronic files; and

• Procedures in place to document the secondary review of log records including those for 

instrument maintenance, standard and reagent preparation, balances, refrigerators and water 

purification systems. 

3.2 Quality Assurance Project Plan for UCMR 4

All laboratories seeking approval to perform chemical analyses for UCMR 4 are required to prepare a 

QAPP specific to UCMR 4. The QAPP supplements the laboratory QMP by documenting the specific 

changes in sample handling, analytical methods, QC, and data reporting that the laboratory makes to 
7

address the UCMR 4 requirements. Laboratories must make this document available to EPA for review, if 

requested. More information regarding the preparation of a QAPP can be found in EPA Requirements for 

Quality Assurance Project Plans (QA/R-5).

3.2.1 General Procedures

Laboratory personnel must be familiar with procedures such as: 

• preparation, labeling, and storage of standards and reagents; 

• preparation of samples for analysis; 

• calibration and operation of analytical instrumentation; 

• monitoring system performance; 

• troubleshooting; 

• maintenance of thorough documentation of activities; 

• maintenance of QC review of log records; and

• reviewing and reporting data.

3.2.2 Standard and Reagent Identifiers

Unique identifiers must be assigned to all chemicals, reagents, solvents, and standards, including 

purchased stock and neat materials, laboratory-prepared stock standards, calibrations standard, QCSs, 

fortification solutions, surrogate solutions, and internal standard solutions. 

3.2.3 Standard Preparation Log Records

Standard preparation log records must document the detail necessary to determine concentrations by 

calculation, including the solvent used, lot number and manufacturer, and preparation and expiration 

dates. The standards that are used in a particular batch must be readily traceable to the standard prep 

log. For instance, the ID of a standard, rather than generic descriptors such as “Ical standard 1,” should 

be referred to in the analytical sequence and on the quantitation reports.

3.2.4 Significant Figures of Reported Results

Calculations must use all available digits of precision, but final reported concentrations should be 

rounded to an appropriate number of significant figures, typically two, and not more than three 

significant figures. Some data in Appendix B are reported with more than two significant figures. This is 

done to better illustrate the method performance data.

4 Methods for UCMR 4 Monitoring

Laboratories must use the methods specified in 40 CFR 141.40 (a)(3), Table 1, to perform UCMR analyses 

during the 3-year UCMR 4 monitoring period. UCMR 4 methods are summarized below and listed in 

Table 1, Section 4.10, of this document. UCMR 4 laboratories must follow all analytical and QC 

procedures outlined in the methods and in this document (see Section 7). Analyses may be conducted 

only by laboratories formally approved by EPA for UCMR 4. Sampling and analysis for UCMR 4 shall not 

begin prior to the monitoring period specified in the final rule.

4.1 EPA Method 200.8 Rev. 5.4, ASTM Method D5673-10, SM 3125B (Referred to as 

EPA 200.8)

Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma–Mass 

Spectrometry

Total recoverable analytes in a 100 mL water sample are solubilized by heating in nitric acid at 85 °C. For 

UCMR 4, all samples for metals analysis by ICP-MS must be digested, regardless of sample turbidity and 
8

method. Microwave digestion, with a reduced sample volume, is allowed only if all QC requirements are 

met. When the sample volume has been evaporated to approximately 20 mL, it is refluxed for an 

additional 30 min and then removed from heat and allowed to cool. The cooled sample is quantitatively 

transferred to a 50 mL Class A glass flask or cylinder. An aliquot of a solution containing internal 

standard is added and the solution is diluted to volume. The sample is then introduced by pneumatic 

nebulization into an argon-based, high-temperature radiofrequency plasma where energy transfer 

processes cause desolvation, atomization, and ionization. The ions are extracted from the plasma 

through a differentially pumped vacuum interface and separated on the basis of their mass-to-charge 

ratio, m/z, by a quadrupole mass spectrometer. The ions are then detected by an electron multiplier or 

Faraday detector. See Section 12, Appendix B, for details regarding specific UCMR 4 analytical 

requirements.

4.2 EPA ELISA Method

Based on Ohio EPA Total (Extracellular and Intracellular) Microcystins - ADDA by ELISA Analytical 

Methodology, Version 2.0, January 2015

EPA anticipates having an EPA enzyme-linked immunosorbent assay (ELISA) method available by the 

publication of the final rule and anticipates that this method will be similar to the Ohio EPA 

methodology. The EPA method for ELISA is an immunoassay for the detection of microcystins in water 

samples. This procedure is an indirect competitive ELISA which allows microcystins and nodularin to be 

detected in a congener-independent manner through recognition by specific antibodies. Microcystins

and nodularin in a sample compete with an immobilized microcystin-protein analogue for the binding 

sites of antibodies in solution. After a washing step and the addition of the substrate solution, a color 

signal is generated. The intensity of the color is inversely proportional to the concentration of the 

microcystin present in the sample. The color reaction is stopped after a specific time and the color is 

evaluated using a microplate reader at 450 nm. See Section 11.2, Appendix A concerning the 

measurement of temperature and pH at the time of collection.

4.3 EPA Method 525.3

Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and 

Capillary Column Gas Chromatography-Mass Spectrometry (GC-MS)

A 1 L water sample is fortified with surrogate analytes and passed through a solid phase extraction (SPE)

device to extract the target analytes and surrogates. The compounds are eluted from the solid phase 

with a small amount of organic solvents. The solvent extract is dried by passing it through a column of 

anhydrous sodium sulfate and is concentrated by evaporation with nitrogen gas. The volume is then 

adjusted to 1 mL with ethyl acetate after adding the internal standards. A splitless injection is made into 

a GC equipped with a high-resolution fused silica capillary column that is interfaced to an MS. The 

analytes are separated and identified by comparing the acquired mass spectra and retention times for 

calibration standards acquired under identical GC-MS conditions. The GC-MS is operated in selected ionmonitoring (SIM) mode. The GC-MS may be calibrated using standards prepared in solvent or using 

matrix-matched standards. The concentration of each analyte is calculated by using its integrated peak 

area with the internal standard technique.

4.4 EPA Method 530

Determination of Select Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and 

Gas Chromatography Mass Spectrometry (GC-MS)
9

A 1 L water sample is fortified with surrogate analytes and passed through a solid phase extraction 

device to extract the target analytes and surrogates. The compounds are eluted from the solid phase 

with a small amount of organic solvents. The solvent extract is dried by passing it through a column of 

anhydrous sodium sulfate and is concentrated by evaporation with nitrogen gas. The volume is then 

adjusted to 1 mL with dichloromethane after adding the internal standards. A splitless injection is made 

into a GC equipped with a high-resolution fused silica capillary column that is interfaced to an MS. The 

analytes are separated and identified by comparing the acquired mass spectra and retention times for 

calibration standards acquired under identical GC-MS conditions. The GC-MS is operated in SIM mode of 

detection. The GC-MS may be calibrated using standards prepared in solvent or using matrix-matched 

standards. The concentration of each analyte is calculated by using its integrated peak area with the 

internal standard technique.

4.5 EPA Method 541

Determination of 1-Butanol, 2-Methoxyethanol, and 2-Propen-1-ol in Drinking Water by Solid Phase 

Extraction and Gas Chromatography-Mass Spectrometry

Fifty milliliter samples are preserved with sodium sulfite and sodium bisulfate. Method and surrogate 

analytes are isolated from water using SPE. The SPE cartridges are dried to remove adsorbed water and 

eluted with 2 mL of 5% methanol in dichloromethane. Extracts are analyzed, without further 

concentration, by GC-MS in the SIM mode of detection. The method analytes are identified by 

comparing the retention times and mass spectra to reference retention times and spectra obtained from 

calibration standards acquired under identical GC-MS conditions. The concentrations of method 

analytes are calculated using the integrated peak area and internal standard technique.

4.6 EPA Method 544

Determination of Microcystins and Nodularin in Drinking Water by Solid Phase Extraction and Liquid 

Chromatography-Tandem Mass Spectroscopy (LC-MS-MS)

A 500 mL water sample, fortified with a surrogate, is filtered and both the filtrate and the filter are 

collected. The filter is placed in a solution of 20% reagent water in methanol and held for at least one 

hour at –20 °C to release the intracellular toxins from the cyanobacteria cells that were captured on the 

filter. The liquid is drawn off the filter and added to the 500 mL aqueous filtrate. The combined sample 

is passed through a solid phase extraction cartridge to extract the method analytes and surrogate. 

Analytes are eluted from the solid phase with a solution of 10% reagent water in methanol. The extract 

is concentrated to dryness by evaporation with nitrogen in a heated water bath, and then adjusted to a 

1 mL volume with a solution of 10% reagent water in methanol. A 10 μL injection is made into an LC 

equipped with a C8 column that is interfaced to an MS-MS. Analytes are separated and identified by 

comparing the acquired mass spectra and retention time to reference spectra and retention times for 

calibration standards acquired under identical LC-MS-MS conditions. The concentration of each analyte 

is determined by external standard calibration. The use of ultra-performance liquid chromatography 

(UPLC) is allowed as part of method flexibility.

4.7 EPA Method 545

Determination of Cylindrospermopsin and Anatoxin-a in Drinking Water by Liquid Chromatography 

Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS-MS)

In the field, a water sample is added to a bottle or vial that contains ascorbic acid (dechlorination agent) 

and sodium bisulfate (microbial inhibitor). In the laboratory, 1 mL of sample is taken for analysis, and 

internal standards are added. An aliquot of the sample is injected into an LC equipped with an analytical 
10

column that is interfaced to an MS-MS. The analytes are separated and identified by comparing 

retention times and reference signals produced by unique mass transitions to retention times and 

reference signals for procedural calibration standards acquired under identical LC-MS-MS conditions. 

The concentration of each analyte is determined using the integrated peak area and the internal 

standard technique. EPA Method 552.3

Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-Liquid Microextraction, 

Derivatization, and Gas Chromatography with Electron Capture Detection

Forty milliliters of sample, fortified with a surrogate standard, are adjusted to pH 0.5 or less. Sodium 

sulfate is added to the sample, which is then extracted with 4 mL of organic solvent, either methyl tertbutyl ether or tert-amyl methyl ether, which contains the internal standard. The solvent phase, 

containing the haloacetic acids, is pipetted off and placed into a tube. A solution of 10% sulfuric acid in 

methanol is added to the solvent extract, and the solution is heated for 2 h. The carboxylic acid groups 

on the haloacetic acids are converted to methyl esters. Concentrated aqueous sodium sulfate is added 

to separate the solvent phase containing the methylated haloacetic acids. The aqueous phase is 

discarded. The extract is neutralized with a solution of sodium bicarbonate and the solvent layer is 

removed for analysis. The target analytes are identified and quantified by capillary column gas 

chromatography using an electron capture detector. Analytes are quantified using procedural standard 

calibration.

4.8 EPA Method 557

Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography 

Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS-MS)

An aliquot of the sample is injected without cleanup or concentration onto an ion exchange column 

specifically designed to separate method analytes from chloride, carbonate, sulfate, and nitrate, which 

are monitored via conductivity detection and then diverted to waste. The analytes of interest are 

directed into the ESI-MS-MS system. Acetonitrile is added post-column to enhance desolvation of the 

method analytes in the ESI interface. Each method analyte is quantitatively identified via a unique mass 

transition, and the concentration is calculated using integrated peak area and the internal standard

technique.

4.9 Table 1: UCMR 4 Chemical Analytes and Methods: Assessment Monitoring.

Analytical Method Contaminants Chemical 

Abstract Service 

Registry 

Number

Minimum 

Reporting 

Level 

(μg/L)

EPA 200.8, ASTM D5673-10, or Germanium 7440-56-4 0.3

SM 3125B Manganese 7439-96-5 0.4

EPA ELISA method Total microcystins NA 0.3

EPA Method 525.3 alpha-Hexachlorocyclohexane 319-84-6 0.01

Chlorpyrifos 2921-88-2 0.03

Dimethipin 55290-64-7 0.2

Ethoprop 13194-48-4 0.03

Oxyfluorfen 42874-03-3 0.05

Profenofos 41198-08-7 0.3

Tebuconazole 107534-96-3 0.2

Total permethrin (cis & trans) 52645-53-1 0.04
11

Analytical Method Contaminants Chemical 

Abstract Service 

Registry 

Number

Minimum 

Reporting 

Level 

(μg/L)

Tribufos 78-48-8 0.07

EPA Method 530 Butylated hydroxyanisole 25013-16-5 0.03

o-Toluidine 95-53-4 0.007

Quinoline 91-22-5 0.02

EPA Method 541 1-Butanol 71-36-3 2.0

2-Methoxyethanol 109-86-4 0.4

2-Propen-1-ol 107-18-6 0.5

EPA Method 544 Microcystin-LA 96180-79-9 0.008

Microcystin-LF 154037-70-4 0.006

Microcystin-LR 101043-37-2 0.02

Microcystin-LY 123304-10-9 0.009

Microcystin-RR 111755-37-4 0.006

Microcystin-YR 101064-48-6 0.02

Nodularin 118399-22-7 0.005

EPA Method 545 Anatoxin-a 64285-06-9 0.03

Cylindrospermopsin 143545-90-8 0.09

EPA Method 552.3 or Bromochloroacetic acid (BCAA) 5589-96-8 0.3

EPA Method 557 Bromodichloroacetic acid (BDCAA) 71133-14-7 0.5

Chlorodibromoacetic acid (CDBAA) 5278-95-5 0.3

Tribromoacetic acid (TBAA) 75-96-7 2.0

Monobromoacetic acid (MBAA) 79-08-3 0.3

Dibromoacetic acid (DBAA) 631-64-1 0.3

Dichloroacetic acid (DCAA) 79-43-6 0.2

Monochloroacetic acid (MCAA) 79-11-8 2.0

Trichloroacetic acid (TCAA) 76-03-9 0.5

5 Initial Demonstration of Capability for UCMR 4 Analyses

Each laboratory seeking approval for UCMR 4 methods must complete an Initial Demonstration of 

Capability (IDC) study for each method. EPA recognizes that a laboratory may use multiple instruments 

and analysts to perform analyses. If more than one analyst performs UCMR 4 analyses, each analyst

must perform an IDC study before they analyze UCMR 4 samples. Similarly, an IDC study must be 

performed using each instrument that will be used to analyze UCMR 4 samples. This will ensure that 

each operator and each instrument maintains the minimum quality standards. Data from each of these 

tests are to be maintained at the laboratory for EPA’s review in the event that the Agency wishes to 

conduct an audit before or during the UCMR 4 monitoring period.

5.1 Submission of IDC Data

IDC study data must be submitted as part of the laboratory approval application package. One set of IDC 

study data, representative of typical performance of the operators and instruments used for the 

applicable method, is to be included in the application package for each method. The UCMR 4 methodspecific application sheets provide the format for reporting these data.
12

5.2 IDC Study Elements

EPA recommends that the laboratory verify the instrument calibration and sensitivity prior to 

performing the IDC study. The lowest calibration curve standard must contain the analytes at a 

concentration at or below the MRL. The IDC study, as described in Sections 5.2.1 through 5.2.4 below,

involves demonstration of: 1) low system background, 2) precision, 3) accuracy, and 4) the ability of the 

laboratory to achieve the MRLs.

5.2.1 Initial Demonstration of Low System Background

Analyze an LRB to verify that all analytes of interest are found to be less than or equal to one-third the 

MRL. See Section 7.7.4, Table 8, for acceptable LRB criteria.

5.2.2 Initial Demonstration of Precision (IDP)

Analyze four to seven laboratory fortified blank (LFB) samples (Section 7.8) that are fortified at a midlevel concentration. The relative standard deviation (RSD) of the resulting analytical data set must meet 

the criterion specified in Table 2, Section 5.3.

5.2.3 Initial Demonstration of Accuracy (IDA)

Calculate the average recovery for the data set generated for the IDP (Section 5.2.2).

AAAAAAAAAAAAAA RR RRRR RR = MMMMMMMM oooo LLLLLLLL

FFFFFF FFFF FFFF CC .

× 100% Equation 1

Average recovery must meet the criteria specified in Table 2, Section 5.3.

5.2.4 MRL Verification

Laboratories must verify they can achieve the UCMR 4 MRL for each analyte according to the procedure 

outlined in Section 6.

5.3 Table 2: IDC Quality Control Requirements for MRL Verification and for Precision

and Accuracy

Analytical Method MRL Verification Requirement Acceptable 

Precision

Acceptable Accuracy

EPA 200.8, ASTM 

D5673-10, or SM 3125B

Metals

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 10%

85 to 115%

EPA ELISA method

Total Microcystins

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

TBD TBD

EPA 525.3

Pesticides

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 20%

70 to 130%, except for 

Dimethipin at 60 to 

130%

EPA 530

Semivolatiles

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 20%

70 to 130%, except for 

o-toluidine at 50 to 

130%

EPA 541

Alcohols

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 20%

70 to 130%

EPA 544

Microcystins & 

Nodularin

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 30%

70 to 130%

EPA 545

Cylindrospermopsin &

Anatoxin-a

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 20%

70 to 130% 
13

Analytical Method MRL Verification Requirement Acceptable 

Precision

Acceptable Accuracy

EPA 552.3 

Haloacetic Acids

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 20%

80 to 120% 

EPA 557

Haloacetic Acids

Lower PIR ≥ 50% recovery and 

Upper PIR ≤ 150% recovery.

RSD less than or 

equal to 20%

70 to 130%

6 Minimum Reporting Level Verification

The MRLs for the UCMR 4 analytes were established by EPA according to the procedure detailed in 

Technical Basis for the Lowest Concentration Minimum Reporting Level Calculator. Data from LCMRLs

determined by multiple laboratories were used. The MRLs established for the UCMR 4 analytes are 

presented in Table 1, Section 4.10. All laboratories performing analysis for the UCMR 4 must be able to 

measure the analyte concentrations at these levels with specified accuracy and precision as given in 

Table 3, Section 7.3.8. As part of the UCMR 4 LAP application process, laboratories must verify they can 

achieve the UCMR 4 MRLs for each analyte according to the procedure in 40 CFR 141.40(a)(5)(iii) and 

outlined in Sections 6.1 through 6.5 that follow.

6.1 Fortify, Process, and Analyze Seven Replicate LFBs at or Below Proposed MRL

Seven LFBs, which contain method analytes at or below the proposed MRL for UCMRL 4, are processed 

through the entire method procedure. These LFBs must contain all method specified dechlorination

agents and preservatives, which are listed in Table 12, Section 8.3.4. The lowest calibration standard 

used in the initial calibration must contain the method analytes at or below the fortification level of 

these LFBs.

6.2 Calculate the mean and standard deviation

Use the results from the analysis of the seven LFB replicates to calculate the mean and standard 

deviation (s) for these replicates. 

6.3 Half range for the prediction interval of results

Determine the half range for the prediction interval of results (HRPIR) using Equation 1:

HH PPPPPP = 3.963 × ss Equation 2

Note that the factor 3.963 is specific only to use of seven replicates.

6.4 Confirm PIR limits are within QC criteria

Confirm that the upper and lower limits for the prediction interval of the result (PIR) satisfy the upper 

and lower recovery limits.

The lower PIR limit must be greater than or equal to 50 percent recovery:

PPPP LL LL = mm −HH PPPPPP

TT TT TT TTTT

× 100% Equation 3

The upper PIR limit must be less than or equal to 150 percent recovery:

PPPP UUUUUU = mm +HH PPPPPP

TT TT TT TTTT

× 100% Equation 4

The MRL is validated if both the upper and lower PIR limits meet these criteria. 

These calculations are illustrated in the Example Calculation of Section 6.5.
14

6.5 Example Calculation of the PIR limits

The true value of the LFB concentration is 0.600 μg/L and LFB analytical results are 0.602, 0.586, 0.549, 

0.606, 0.622, 0.578, and 0.667 μg/L. The given data have at least three significant figures so that, during 

calculations, the variance is not censored.

6.5.1 Step 1: Calculate the mean

mm mm = SS oooo LLLLLL

nn oooo = 0.6014

6.5.2 Step 2: Calculate the standard deviation (s)

ss = �∑ (LLLLLL−mm ) nn 2 ii=1

( −1) = �0.00829

6 = 0.0372

6.5.3 Step 3. Calculate the Half Range for the PIR (HRPIR)

HH = 3.963 × ss = 3.963 × 0.0372 = 0.147

6.5.4 Step 4. Calculate the Lower PIR Limit (PIR lower)

PPPP LL LL = mm −HH PPPPPP

TT TT TT TTTT

× 100% = 0.6014−0.147

0.60

× 100% = 75.7%

which passes criteria of greater than or equal to 50%.

6.5.5 Step 5. Calculate the Upper PIR Limit (PIR upper)

PPPP UUUUUU = mm +HH PPPPPP

TT TT TT TTTT

× 100% = 0.6014+0.147

0.60

× 100% = 124.7%

which passes criteria of less than or equal to 150%. The MRL is validated if both the Upper and Lower 

PIR Limits meet the criteria described in this section.

7 Quality Control Requirements

Laboratories must follow the QC procedures outlined in the methods and in Section 4 of this manual.

Before field samples are analyzed, an IDC (Section 5) must be performed. During the analysis of field 

samples, ongoing QC requirements must be met for Calibration and for Analysis, Extraction, and 

Digestion Batch. These include continuing calibration checks (CCCs), surrogate standards, internal 

standards, laboratory reagent blank (LRB), laboratory fortified blank (LFB), quality control sample (QCS), 

and Laboratory Fortified Sample Matrixes (LFSM and LFSMD). These QC requirements are considered 

the minimum acceptable. Laboratories are encouraged to add QC practices that meet their specific 

needs, however, additional practices must also meet method criteria to consider analytical results valid.

7.1 Extraction Batch and Digestion Batch

An Extraction Batch is defined as all samples prepared and extracted together by the same person 

during a work day. A Digestion Batch includes all samples digested together by the same person during a 
15

work day. The same lots of reagents, solvents, internal standard, surrogate standard, and analyte 

fortification solutions must be used for all samples included in an Extraction or Digestion Batch. For 

methods that use solid phase extraction (SPE) techniques, it is preferable to use the same lot of pretested SPE media. A maximum of twenty field samples, not including QC samples, can be in an Extraction 

Batch or Digestion Batch. The Extraction Batch or Digestion Batch must be identified with a unique and 

traceable ID code or name. Each Extraction Batch or Digestion Batch must include at a minimum an LRB

(Section 7.7), an LFB (Section 7.8) spiked at a concentration less than or equal to the MRL, and an LFSMLFSMD pair (Section 7.10). Results from the analysis of these QC samples are used to evaluate the 

validity of the sample processing procedures.

7.2 Analysis Batch

An Analysis Batch is defined as a group of field samples analyzed using the same instrument within a 24 

hour period that begins and ends with the analysis of the appropriate CCC standards. An Analysis Batch

cannot include more than twenty field samples. QC samples, such as the LRB, LFBs, FD, LFSM, LFSMD

and CCCs, are not counted as part of the twenty field sample limit. Conditions for the Analysis Batch 

must be the same as those used during calibration.

7.2.1 Analysis Batch Field Samples

An Analysis Batch may be comprised of field samples from the same Extraction Batch or Digestion Batch

or from several batches. Ideally, field samples and corresponding QC samples from the same Extraction 

or Digestion Batch are analyzed in the same Analysis Batch. Field samples with QC failures may be reanalyzed immediately within the same Analysis Batch, or if this is not possible in a new Analysis Batch

with the appropriate QC samples (see Section 7.11).

7.2.2 Analysis Batch Identifier

Each Analysis Batch must be identified with a unique and traceable ID code or name that is different 

than the Extraction or Digestion Batch ID used in processing the samples.

7.3 Initial Calibration of Analytical Instruments

Each method describes initial calibration procedures used to determine the concentrations of the 

method analytes. Some methods allow more than one option. The laboratory must select and follow 

one of the initial calibration procedures outlined in the approved method in order to meet the 

requirements of UCMR 4. For mass spectrometry methods, laboratories must meet the method-specific 

mass spectrometer tuning criteria prior to performing the initial calibration procedure.

7.3.1 Calibration Fit

If allowed by the method, different types of calibration, such as linear regression, quadratic regression, 

and response factor, and different fit types, such as forcing the curve through the origin, ignoring the 

origin, and weighting factors, may be used for different analytes within a given method. However, the 

same calibration and fit type must be used for a given analyte for all analyses that are based on a given 

initial calibration. If modifications to the calibration or fit type are made, the instrument must be 

recalibrated. See Section 10.2.8, Appendix B for special instructions on EPA Method 200.8.

7.3.2 Calibration Range

The calibration curve for each UCMR 4 method must span the expected concentration range of the 

samples being analyzed, and must include a standard with a concentration less than or equal to the 

MRL. Laboratories must use a minimum of five calibration standards for all UCMR 4 methods. More than 

five standards must be used if specified by the method, such as EPA Methods 530, 525.3, 541 and ELISA.

See Appendix B, Sections 10.2.7 and 10.2.9 for special instructions on EPA Method 200.8.
16

7.3.3 Preservatives in Calibration Standards for Some Methods

Calibration standards for Methods 200.8, 545, 552.3 and 557 require the addition of the preservatives 

and dechlorination agents that are used in the field samples. Method 525.3 and 530 require the addition 

of the preservatives and dechlorination agents when matrix matched calibration solutions are prepared.

7.3.4 Surrogate Recovery and Internal Standard Response in Initial Calibration Standards

The recovery of UCMR 4 analytes, surrogate standards, and internal standards must be monitored in the 

initial calibration standards using the calibration curve created from the initial calibration data. 

Recoveries must meet the criteria defined in Table 3, Section 7.3.8. If any surrogate fails the criterion in 

a calibration standard, the data from that standard cannot be used in calculating the calibration curve. If 

an internal standard fails criteria in a calibration standard, then the calibration standard cannot be used 

in the calibration. If all surrogate and internal standards pass the criteria, but only some of the analytes 

pass the recovery criteria, only the data for the passing analytes may be used in calculating the 

calibration curve.

7.3.5 Holding Time for Standard Solutions

Laboratories must adhere to the holding time limitations for standard solutions, reagents, and solutions, 

as specified in the individual methods. If multiple stock solutions are used, the shortest expiration date 

applies. It is critical that laboratories closely monitor the expiration of calibration standards.

7.3.6 Initial Calibration Acceptance Criteria 

Laboratories must adhere to QC criteria limits and are not permitted to accept sample data when any 

QC parameter fails QC criteria limits. All QC criteria must be implemented. For methods 525.3, 530, 541, 

544, 545, 552.3 and 557, calibration standard responses must be entered into the calibration curve 

equation and the recalculated concentrations must meet the accuracy criteria listed in Table 3, Section 

7.3.7. All criteria in Table 3, Section 7.3.7 must pass or the result must not be used in the generation of 

the calibration curve. For instance, if a surrogate fails criteria in a calibration standard, then the results 

for that standard, for all analytes, must not be used. If an internal standard fails criteria, then the 

associated analyte results cannot be used for calibration. The calibration curve for each analyte is valid 

only if it includes data for five, or more if specified by the method, concentration levels, including one at 

or below the MRL concentration.

7.3.7 Table 3. Initial Calibration Acceptance Criteria

Analytical Methods Analyte 

Percent 

Recovery 

Greater than 

MRL

Analyte Percent 

Recovery Near 

MRL

Surrogate 

Percent 

Recovery 

Internal Standard 

Response

EPA 200.8,

ASTM D5673-10,

SM 3125B

Metals

90 to 110% 50 to 150% NA 60 to 125%

ELISA method

Total Microcystins

TBD TBD NA TBD

EPA 525.3

Pesticides

70 to 130% 50 to 150% 70 to 130% 50 to 150% of mean in 

initial calibration.
17

Analytical Methods Analyte 

Percent 

Recovery 

Greater than 

MRL

Analyte Percent 

Recovery Near 

MRL

Surrogate 

Percent 

Recovery 

Internal Standard 

Response

EPA 530

Semivolatiles

70 to 130% 50 to 150% 70 to 130% for 

Quinoline-d7

and 50 to 

130% for oToluidine-d9

50 to 150% of mean in

initial calibration

EPA 541

Alcohols

70 to 130% 50 to 150% 70 to 130% 50 to 150% of mean in 

initial calibration

EPA 544

Microcystins & 

Nodularin

70 to 130% 50 to 150% 70 to 130% NA

EPA 545

Cylindrospermopsin 

& Anatoxin-a

70 to 130% 50 to 150% NA 50 to 150% of mean in

initial calibration

EPA 552.3

Haloacetic acids

70 to 130% 50 to 150% 70 to 130% 50 to 150% of mean in 

initial calibration

EPA 557

Haloacetic acids

70 to 130% 50 to 150% NA 50 to 150% of mean in 

initial calibration

7.4 Continuing Calibration Checks (CCCs)

7.4.1 Initial Low-Level CCC

Prior to the analysis of field samples, the initial calibration must be verified with a low-level CCC 

standard at a concentration at or below the MRL. Even if initial calibration standards are analyzed on the 

day of analysis, laboratories must analyze a low-level CCC standard prior to field samples. The initial lowlevel CCC standard must meet QC criteria for the results of the Analysis Batch to be acceptable.

7.4.2 Mid- and High-Level CCC

A CCC standard, alternating between the mid- and high-level concentrations, must be run after every 

ten, or less, field samples and at the end of the Analysis Batch. CCC standards must meet the criteria 

defined in Table 4. All samples must be preceded and followed by CCC standards that pass the criteria. 

Analytical results for a group of up to ten samples are considered valid only if the CCC standards 

analyzed before and after the group meet the criteria. Note that the high-level CCC can be less than the 

highest concentration on the calibration curve.

7.4.3 CCC Criteria “High” Exception

The limited exception for the CCC criteria is when no measured result for a target analyte is found in 

field samples and a CCC result for that analyte fails because of high bias. This exception does not apply 

to surrogate or internal standard recoveries in any samples, field or QC. This exception is expected to be 

rare and not routinely applied by the laboratory. Corrective action must be taken by the lab to 

investigate the root cause and minimize the frequency of target analyte high bias CCC results. 

7.4.4 Trouble-Shooting CCC Failure

If criteria are not met for an analyte in a CCC standard, then the source of the problem affecting the 

problem analyte must be identified and eliminated. This may require instrument maintenance and the 
18

generation of a new instrument calibration curve. After the problem is resolved, all samples or extracts 

analyzed between the failing CCC standard and the previously acceptable CCC standard must be 

reanalyzed for the analyte that failed QC criteria. If the samples or extracts cannot be reanalyzed, then 

data for the problem analyte are considered invalid for those samples and the data must not be 

reported.

7.4.5 Table 4. CCC Acceptance Criteria

Analytical Methods Analyte Percent 

Recovery Mid 

and High Level

Analyte Percent 

Recovery Low 

Level

Surrogate 

Percent 

Recovery 

Internal Standard 

Response

EPA 200.8,

ASTM D5673-10,

SM 3125B

Metals

85 to 115% 50 to 150% NA 60 to 125% of response in 

calibration blank

EPA ELISA method

Total Microcystins

TBD TBD NA NA

EPA 525.3

Pesticides

70 to 130% 50 to 150% 70 to 130% 50 to 150% of mean in

initial calibration and 70 

to 130% of previous CCC.

EPA 530

Semivolatiles

70 to 130% 50 to 150% 70 to 130% 50 to 150% of mean in

initial calibration and 70 

to 130% of previous CCC

EPA 541

Alcohols

70 to 130% 50 to 150% 70 to 130% 50 to 150% mean in initial 

calibration

EPA 544

Microcystins & 

Nodularin

70 to 130% 50 to 150% 70 to 130% NA

EPA 545

Cylindrospermopsin 

& Anatoxin-a

70 to 130% 50 to 150% NA 50 to 150% of mean in 

initial calibration

EPA 552.3

Haloacetic acids

70 to 130% 50 to 150% 70 to 130% 50 to 150% of mean in

initial calibration

EPA 557

Haloacetic acids

70 to 130% 50 to 150% NA 50 to 150% mean in initial 

calibration and 70 to 130% 

of previous CCC.

7.5 Surrogate Requirements and Criteria

A surrogate is a pure analyte that is used to monitor method performance from processing through 

analysis for methods involving sample extraction. A surrogate standard is added to the aqueous sample 

in a known amount before the sample is processed. A surrogate is measured with the same procedures 

used to measure other sample components. A surrogate analyte must be added to all aqueous samples,

including LRBs, LFBs, LFSMs and LSFMDs, and to all standards. A surrogate analyte is required for 

Methods 525.3, 530, 541, 544, and 552.3. The surrogate analytes are listed in Table 5, Section 7.5.1,

along with recovery criteria. When the method provides flexibility in the selection of the surrogate or its 

concentration, EPA allows the same flexibility for UCMR 4. However, the concentration of each 

surrogate analyte must be the same in calibration standards as it is in field and QC samples, or their 

extracts or digestates, whichever is introduced into the analytical instrument.
19

7.5.1 Surrogate Recovery

The percent recovery of the surrogate in a sample is calculated by comparing the analytically measured 

concentration to the fortified concentration, as shown in Equation 5.

SSSS SS % RR RRRR RR = MMMMMM MMMM SS SS

EEEE SS SS

× 100% Equation 5

7.5.2 Trouble-Shooting Surrogate Failure in the Sample

A sample that fails QC criteria for surrogate recovery should be rerun in case a mis-injection occurred. If 

the sample continues to fail surrogate QC criteria, the laboratory should process a new aliquot of the 

sample. Typically, data for samples with failed surrogate recovery must not be reported. If surrogate 

recovery fails criteria, but is close to QC limits, contact EPA to discuss. Excessive surrogate recovery 

failure, though, could lead to an EPA audit.

7.5.3 Surrogate Failure in LRB or LFB

If the surrogate recovery fails the acceptance criteria in an LRB or in a required LFB, the LRB or LFB may 

be reanalyzed later in the Analysis. If surrogate recovery fails again, all field sample results for the 

Extraction or Digestion Batch for that LRB or LFB are invalid and must not be reported. If the surrogate 

recovery fails in an LRB that is needed to pass an Analysis Batch, all data for that Analysis Batch are 

invalid and must not be reported. If possible, the laboratory should process new aliquots of the affected 

samples; if this is not possible, the affected field samples must be recollected. One LFB must pass 

surrogate recovery within a 24-h period of analysis. If not, the samples in the Analysis Batches that 

correspond to that required LFB, cannot be reported.

7.5.4 Surrogate Failure in LFSM or LFSMD

If the surrogate recovery in an LFSM or LFSMD fails the acceptance criteria, but all other batch QC pass, 

only the fortified matrix sample with the failed surrogate is impacted and must not be reported. If the 

surrogate recovery in the LFSM fails and the LFSMD passes, then the LFSMD data should be reported as

the LFSM so that accuracy can be assessed. If both LFSM and LFSMD fail, no matrix spike data are 

reported. Surrogate recovery failure of the LFSM and LFSMD does not invalidate the associated 

unfortified sample results.

7.5.5 Table 5. Surrogate Standards, Concentrations, and Recovery Criteria

Analytical Method Surrogate Standard Concentration 

in Sample

Acceptance Criteria 

as Percent Recovery

EPA 200.8, ASTM 

D5673-10, SM 3125B

Metals

NA NA NA

ELISA method

Total Microcystins

NA NA NA

EPA 525.3

Pesticides

1,3-dimethyl-2-nitrobenzene

Triphenyl phosphate

Benzo[a]pyrene-d12

5 μg/L

5 μg/L

5 μg/L

70 to 130%

EPA 530

Semivolatiles

o-toluidine-d9

quinolone-d7

5 μg/L

5 μg/L

70 to 130%

EPA 541

Alcohols

1-Butanol-d10

2-Propen-1-ol-d6

10 μg/L

10 μg/L

70 to 130%
20

Analytical Method Surrogate Standard Concentration 

in Sample

Acceptance Criteria 

as Percent Recovery

EPA 544

Microcystins & 

Nodularin

Ethylated microcystin-LR, d5 0.260 μg/L 60 to 130%

EPA 545

Cylindrospermopsin & 

Anatoxin-a

NA NA NA

EPA 552.3

Haloacetic acids

2-Bromobutanoic acid 10 μg/L 70 to 130%

EPA 557

Haloacetic acids

NA NA NA

7.6 Internal Standard Requirements and Criteria

An internal standard is a pure compound that is added to standards, extracts, digestates, and directinject samples in a known amount and that is used to estimate the relative response of a method 

analyte and surrogate analyte that are contained in the same solution. The internal standard must

respond to instrument conditions and sample matrix in a similar manner as the method analytes. The 

internal standard must have no potential to be present in the collected water samples and must not be a 

method analyte. Internal standards are required for calibration and quantitation purposes in all UCMR 4 

methods, with the exception of Method 544 and the ELISA method.

7.6.1 Calculation of Internal Standard Recovery

Internal Standard (IS) recovery is calculated using Equation 6.

II SSSS SS SS RR RRRR RR = AA SS

AAAA AA oooo CC

× 100% Equation 6

7.6.2 Internal Standard Recovery Criteria

Table 6 of Section 7.6.6 lists the internal standards and the analytical acceptance criteria. When the 

method provides flexibility in the concentration of the internal standard, EPA allows the same flexibility 

for UCMR 4. However, the internal standard concentration in the calibration standards must be the 

same as is in the field samples, QC samples, and extracts or digestates, whichever is introduced into the 

analytical instrument.

7.6.3 Internal Standard Failure in Sample

If the internal standard recovery in a sample fails the acceptance criteria, then the results for the 

analytes that are associated with the internal standard in that sample are invalid. Data that fail internal 

standard criteria must not be reported. If possible, the laboratory should process a new aliquot of the 

sample; if this is not possible, the field sample must be recollected.

7.6.4 Internal Standard Failure in LRB or LFB

For an Extraction Batch or Digestion Batch, if the internal standard recoveries in an LRB or LFB fail the 

acceptance criteria, all data for the analytes that are associated with that internal standard in that 

Extraction Batch or Digestion Batch are invalid and must not be reported. If the internal standard 

recoveries in an LRB fail the acceptance criteria in an Analysis Batch, all data for the analytes that are

associated with that internal standard in the Analysis Batch are invalid and must not be reported. If 

possible, the laboratory should process new aliquots of the affected samples.
21

7.6.5 Internal Standard Failure in LFSM or LFSMD

If the internal standard recovery in an LFSM or LFSMD fail the acceptance criteria, but all other batch QC 

pass, only the fortified matrix sample with the failed internal standard is impacted and data for the 

analytes that are associated with that internal standard cannot be reported. If the LFSM fails, the LFSMD 

data should be substituted for the LFSM such that accuracy can be assessed. If both LFSM and LFSMD 

fail, no matrix spike data are to be reported. Internal standard recovery failure of the LFSM and LFSMD 

does not invalidate the associated sample results in the Extraction, Digestion, or Analysis Batch.

7.6.6 Table 6. Internal Standards Criteria

Analytical Method Internal Standard Recommended 

Concentration in 

Method

Acceptance Criteria

EPA 200.8, ASTM 

D5673-10, SM 3125B

Metals

Scandium

Indium

Terbium

20 to 200 μg/L

20 to 200 μg/L

20 to 200 μg/L

60 to 125% of mean in 

initial calibration

ELISA method

Total Microcystins

NA NA NA

EPA 525.3

Pesticides

Acenaphthene-d10

Phenanthrene-d10

Chrysene-d12

1 μg/mL (SIM)

1 μg/mL (SIM)

1 μg/mL (SIM)

70 to 130% of previous 

CCC and 50 to 150 % of

mean in initial 

calibration.

EPA 530

Semivolatiles

Acenaphethen-d10

Phenanthrene-d10

500 μg/L (SIM)

500 μg/L (SIM)

70 to 130% of previous 

CCC and 50 to 150% of

mean in initial 

calibration.

EPA 541

Alcohols

1,4-dioxane-d8

Chlorobenzene-d5

0.25 μg/mL

0.25 μg/mL

70 to 130% of previous

CCC and 50 to 150% of 

mean in initial 

calibration

EPA 544

Microcystins & 

Nodularin

No internal standard NA NA

EPA 545

Cylindrospermopsin 

& Anatoxin-a

L-Phenylamine-d5

Uracil-d4

5.00 μg/L

20.0 μg/L

50 to 150% of mean in 

initial calibration.

EPA 552.3

Haloacetic acids

1,2,3-trichloropropane 1.00 μg/mL 50 to 150% of mean in 

initial calibration.

EPA 557

Haloacetic acids

Monochloroacetic acid-2-

13C

Monobromoacetic acid-I13C

Dichloroacetic acid-2-

13C

Trichloroacetic acid-2-

13C

4 ng/mL 

4 ng/mL

4 ng/mL

4 ng/mL

50 to 150% of mean in 

initial calibration.

7.7 Laboratory Reagent Blank

A laboratory reagent blank (LRB) is an aliquot of reagent water that is treated exactly as a sample. The 

LRB is exposed to all glassware, equipment, solvents, reagents, internal standards, and surrogate 

standards that are used with the other samples in the Extraction Batch. The LRB is used to show that

method analytes or interferences are not present in the laboratory environment, reagents, or 
22

apparatus. For all methods approved for UCMR 4 monitoring, an LRB is required in each Extraction or

Digestion Batch. Methods that require the extraction or digestion of samples must process a minimum 

of one LRB with every batch of twenty or fewer field samples. Methods, such as Method 545, which

involve the direct analysis of samples, require a minimum of one LRB analyzed for every twenty or fewer 

field samples. When more than one Extraction or Digestion Batch of samples are processed within a 24-

her period, an LRB must be processed with each Extraction or Digestion Batch.

7.7.1 Laboratory Reagent Blank Acceptance Criteria

Internal standard recovery for the LRB must pass acceptance criteria given in Table 5 of Section 7.5.5

and surrogate standard recovery must pass acceptance criteria in Table 6 of Section 7.6.6. Also, 

background contamination must not interfere with accurate measurement of the UCMR 4 analytes. If a

method analyte is detected in the LRB at a concentration greater than the criteria specified in Table 7 of 

Section 7.7.2, then all data for the problem analyte are considered invalid for all samples of an

associated Extraction or Digestion Batch, or for an Analysis Batch when samples are directly injected. If 

the samples cannot be re-processed, the failed data must be flagged as not meeting the QC criteria and 

must not be reported and those samples must be recollected. The source of the problem should be

identified and eliminated before more samples are processed.

7.7.2 Table 7: LRB Analytes Must Be Less Than or Equal to One-Third the MRL

Analytical Method Contaminants Analytes Must Be Less than or 

Equal to One-Third the MRL

(μg/L)

EPA 200.8, ASTM D5673-10, or Germanium 0.10

SM 3125B Manganese 0.13

EPA ELISA method Total microcystins 0.10

EPA Method 525.3 alpha-Hexachlorocyclohexane 0.0033

Chlorpyrifos 0.010

Dimethipin 0.067

Ethoprop 0.010

Oxyfluorfen 0.017

Profenofos 0.10

Tebuconazole 0.067

Total permethrin (cis & trans) 0.013

Tribufos 0.023

EPA Method 530 Butylated hydroxyanisole 0.010

o-Toluidine 0.0023

Quinoline 0.0067

EPA Method 541 1-Butanol 0.67

2-Methoxyethanol 0.13

2-Propen-1-ol 0.17

EPA Method 544 Microcystin-LA 0.0027

Microcystin-LF 0.0020

Microcystin-LR 0.0067

Microcystin-LY 0.0030

Microcystin-RR 0.0020

Microcystin-YR 0.0067

Nodularin 0.0017
23

Analytical Method Contaminants Analytes Must Be Less than or 

Equal to One-Third the MRL

(μg/L)

EPA Method 545 Anatoxin-a 0.010

Cylindrospermopsin 0.030

EPA Method 552.3 or Bromochloroacetic acid (BCAA) 0.10

EPA Method 557 Bromodichloroacetic acid (BDCAA) 0.17

Chlorodibromoacetic acid (CDBAA) 0.10

Tribromoacetic acid (TBAA) 0.67

Monobromoacetic acid (MBAA) 0.10

Dibromoacetic acid (DBAA) 0.10

Dichloroacetic acid (DCAA) 0.067

Monochloroacetic acid (MCAA) 0.67

Trichloroacetic acid (TCAA) 0.17

7.8 Laboratory Fortified Blank (LFB)

The Laboratory Fortified Blank (LFB) is an aliquot of reagent water to which known quantities of the 

method analytes are added in the laboratory. The LFB is processed exactly like a sample, including the 

addition of reagents for sample dechlorination and preservation. The same lot of reagents, internal 

standard, and surrogate standard solutions must be used for all samples included in an Extraction Batch 

or Digestion Batch. Results from the LFB samples provide information about the entire method, from 

sample processing to analyte separation and detection. An LFB must be processed with each Extraction 

Batch or Digestion Batch of twenty or fewer samples. The LFB is fortified at or below the MRL. An LFB is 

required to be analyzed as a daily performance check. As described in (40 CFR 141.40(a)(5)(iii)(B)(2), 

once the laboratory has performed an IDC (Section 5.2), a daily performance check is performed for 

each analyte and method. A fortified laboratory blank, at or below the MRL for each analyte, must be 

processed through the entire method procedure during each 24-h period of analysis. If the recovery is 

50% to 150%, inclusive, the daily performance of the laboratory has been validated. The results for any 

analyte for which 50% to150% recovery cannot be demonstrated during the daily check are not valid. 

Laboratories may elect to re-run the daily performance check sample if the performance for any analyte 

or analytes cannot be validated. If performance is validated for these analytes, the laboratory 

performance is considered validated. Alternatively, the laboratory may re-calibrate and repeat the 

performance validation process for all analytes.

7.8.1 Method Requirements for LFB

EPA Methods 200.8, 525.3, 530, and 544 require the extraction and analysis of an LFB. Since Methods 

545, 552.3 and 557 use procedural calibration standards, a CCC is the same as an LFB, so a separate LFB 

is not required. LFB acceptance criteria for analyte, surrogate, and internal standard are listed in Table 8, 

Section 7.8.3.

7.8.2 Laboratory Fortified Blank Criteria Failure

If the LFB recovery fails criteria listed in Table 8, Section 7.8.3, then all data for the problem analyte are

considered invalid for all samples in the Extraction or Digestion Batch. Data of the analyte that fails 

recovery criteria for the LFB must not be reported for that Extraction or Digestion Batch. If the LFB 

surrogate or internal standard fails QC criteria, all data for the Extraction or Digestion Batch must not be 

reported and EPA should be contacted.
24

7.8.3 Table 8. Laboratory Fortified Blank Acceptance Criteria

Analytical Method Analyte Recovery 

Low Level

Surrogate 

Recovery 

Internal Standard Response

EPA 200.8, ASTM 

D5673-10, SM 3125

Metals

50 to 150% No 

Surrogate

60 to 125% of mean in initial calibration

ELISA method

Total Microcystins

No LFB No LFB No LFB

EPA 525.3

Pesticides

50 to 150% 70 to 130% 50 to 150% of mean in initial calibration

and 70 to 130% of previous CCC.

EPA 530

Semivolatiles

50 to 150% 70 to 130% 50 to 150% of mean in initial calibration

and 70 to 130% of previous CCC.

EPA 541

Alcohols

50 to 150% 70 to 130% 50 to 150% of mean in initial calibration

and 70 to 130% of previous CCC.

EPA 544

Microcystins & 

Nodularin

50 to 150% 70 to 130% No Internal Standard

EPA 545

Cylindrospermopsin 

& Anatoxin a

No LFB No LFB No LFB

EPA 552.3

Haloacetic acids

No LFB No LFB No LFB

EPA 557

Haloacetic acids

No LFB No LFB No LFB

7.9 Quality Control Sample (QCS)

A quality control sample (QCS) is a solution containing method analytes of known concentration that is

obtained from a second source that is different from the source used to prepare the calibration 

standards. The purpose of the QCS is to verify the accuracy of the primary calibration standards. The 

QCS must contain internal standards from the same source used in the initial calibration standards. The 

frequency requirements and the analyte recovery criteria for the QCS are given in Section 7.9.2, Table 9.

EPA recommends the concentration of the QCS be near the midpoint of the calibration curve. When a 

second source is not available, laboratories may use a different lot than was used for the calibration 

standards. The QCS must be run within an Analysis Batch.

7.9.1 Analysis Frequency of QCS

Table 9 of Section 7.9.2 lists the minimum QCS analysis frequency for each UCMR 4 analytical method. 

Laboratories may analyze a QCS more frequently to monitor method and analyte performance. Failure 

to analyze a QCS at method-required frequencies is viewed as a deficiency and a “finding” during a 

laboratory audit. If a QCS fails QC criteria, do not report QCS results to the EPA electronic data reporting 

system.

7.9.2 Table 9. QCS Frequency Requirements and Analyte Recovery Criteria

Analytical Method Analyte Recovery 

Criterion

QCS Frequency Requirement

EPA 200.8, ASTM D5673-10,

SM 3125

Metals

90 to 110% During IDC and at least quarterly.
25

Analytical Method Analyte Recovery 

Criterion

QCS Frequency Requirement

ELISA method

Total Microcystins

75 to 125% During IDC and every batch of samples

EPA 525.3

Pesticides

70 to 130% During IDC and after every initial calibration

EPA 530

Semivolatiles

70 to 130% During IDC and after every initial calibration

EPA 541

Alcohols

80 to 120% During IDC and at least quarterly

EPA 544

Microcystins & Nodularin

70 to 130% During IDC

EPA 545

Cylindrospermopsin & 

Anatoxin-a

70 to 130% During IDC and at least quarterly

EPA 552.3

Haloacetic acids

70 to 130% During IDC and at least quarterly

EPA 557

Haloacetic acids

70 to 130% During IDC, each time new analyte primary 

standard is prepared and at least quarterly.

7.10 Laboratory Fortified Sample Matrix & Laboratory Fortified Sample Matrix Duplicate

7.10.1 Laboratory Fortified Sample Matrix

A laboratory fortified sample matrix (LFSM) is a field sample containing preservatives to which known 

quantities of the method analytes are added in the laboratory. The LFSM is processed and analyzed as a 

field sample, and its purpose is to determine whether the sample matrix contributes bias to the 

analytical results. The concentrations of the analytes in the unfortified sample matrix must be 

determined in a separate aliquot.

7.10.2 Laboratory Fortified Sample Matrix Duplicate 

Field duplicate samples are collected at the same time, shipped, and stored under identical conditions. 

Field duplicate results are often used to estimate method precision. However, when method analytes 

are rarely found at concentrations greater than the MRL, a laboratory fortified sample matrix duplicate 

(LFSMD) is used to assess method precision. LFSMD samples are used to determine the precision of 

UCMR 4 monitoring data, because it may not be possible to know which samples may contain 

measurable concentrations of method analytes.

7.10.3 Frequency and Concentration Level of LFSM and LFSMD

One LFSM and one LFSMD must be processed with the associated unfortified field sample in each 

Extraction Batch or Digestion Batch. In subsequent Extraction Batch or Digestion Batch, the fortification 

concentration of the LFSM and the LFSMD must be alternated between a low- and mid-level 

concentration. For example, two Extraction Batches will require preparation and analysis of two LFSMLFSMD sets, one set fortified at the low-level and one at the mid-level concentration. Laboratories must 

ensure they receive sufficient sample volume to meet the UCMR 4 required frequency of 1 LFSM-LFSMD 

set per Extraction Batch or Digestion Batch, which consists of 20 or fewer field samples.
26

7.10.4 Fortification Levels of LFSM-LFSMD

The fortification concentration of the LFSM and the LFSMD must be alternated between a 

low- and mid-level concentration from batch to batch. For example, two extraction batches 

will require the preparation and analysis of two LFSM/LFSMD sets, one set fortified at the 

low-level and one at the mid-level concentration. The low-level LFSM-LFSMD fortification 

concentration must be within 50 to 150% of the MRL for each contaminant. For example, for 

an MRL of 1.0 μg/L, fortification levels between 0.50 μg/L and 1.5 μg/L are acceptable. The 

mid-level LFSM-LFSMD fortification concentration should be 80 to 120% of the mid-level 

calibration standard for each contaminant. When the laboratory has data from previously 

analyzed samples, the fortification concentration should approximate the average 

concentration observed in previous analyses. If UCMR 4 contaminants are regularly found in 

field samples at concentrations exceeding the MRL, laboratories may find it difficult to derive 

meaningful results from samples fortified with that contaminant at the low-level 

concentration. In such cases, laboratories should apply their experience to adjust fortification 

to levels more appropriate for native levels.

7.10.5 Recovery Criteria Not Specified for LFSM and LFSMD 

For UCMR 4, there are no method analyte recovery acceptance criteria specified for LFSM and LFSMD 

results. Data should not be rejected based on the recovery of fortified target analytes or on the 

precision between the LFSM and LFSMD, provided internal standard and surrogate standard recoveries 

and all other QC results are valid. LFSM and LFSMD results are to be reported to EPA’s electronic data 

reporting system. If surrogate or internal standard recovery fail criteria in the LFSM and LFSMD, do not 

report results. If one of the fortified samples fails QC, then the results of the fortified sample that 

passes, should be reported as the LFSM. The entire Analysis Batch does not need to be reanalyzed 

because of a failure of a surrogate or internal standard in the LFSM or LFSMD. Recollection of the field 

sample is not required as a result of a surrogate or internal standard failure in the LFSM/LFSMD.

7.11 Sequence of Injection for Analysis Batch

The sequence of analysis for field and QC samples is important for assessing system performance. As 

described in Section 7.2, each Analysis Batch must begin with an initial low-level CCC, at or below the 

MRL, for each of the UCMR 4 method analytes. This initial low-level CCC must be analyzed whether or 

not the initial calibration was generated the same day. The analysis of up to ten field samples can then 

follow. After these ten field samples, the calibration must be verified by the analysis of a mid- or highlevel CCC. If this CCC passes QC criteria, then up to ten additional field samples may be analyzed. The 

Analysis Batch must end with the analysis of a mid- or high-level CCC, whichever level was not analyzed 

after the first ten samples. Each Analysis Batch must contain an LRB. An LFB does not have to be in each 

Analysis Batch but one LFB must be run during each 24-h period of analysis. For example, if two Analysis 

Batches are run within 24-h, only one has to contain an LFB. The LRB, LFB, LFSM, and LFSMD can be run 

in any order, though it is recommended that the LRB and LFB be run at the beginning of that Analysis 

Batch because if the LRB and LFB fail QC criteria, all samples in the Analysis Batch cannot be reported.

7.11.1 Example of Analytical Sequence for an Analysis Batch

Table 10 of Section 7.11.2 illustrates a valid analytical sequence for an Analysis Batch for Method 525.3

that meets QC requirements. Note that Method 525.3 has an LFB, but when procedural standards are 

used or when samples are directly injected without processing, an LFB would be the same as a CCC, and 

so an LFB would not processed. The acquisition start time of the final CCC must be within twenty-four
27

hours of the acquisition start time of the initial CCC, which marked the beginning of the Analysis Batch.

More than one Analysis Batch is permitted within 24 h. A hard copy or electronic copy of the analytical 

sequence must be retained with the data package.

7.11.2 Table 10: Example 2. Valid Analysis Batch for Method 525.3.

Injection # Sample Description Acceptance Criteria for 

Method Analyte

Corrective Action

1 CCC less than or 

equal to MRL

50 to 150% Instrument maintenance to recover 

sensitivity, followed by 

recalibration and verification of 

sensitivity by a low level CCC

2 LRB All target analytes less than 

or equal to 1/3 MRL

Identify and correct source of 

contamination

3 LFB Fortified near MRL, 50 to 

150%

Identify and correct source of 

problem

4 through 

13

Field Samples 1 to 

10

Positive ID of analyte is 

verified if peak retention 

time criteria is satisfied and 

mass spectral identification 

is confirmed.

Identify and correct source of 

problem

14 Mid-level CCC 70 to 130% Instrument maintenance followed 

by recalibration

15 Field sample 11 

associated with 

LFSM and LFSMD

Positive ID of analyte is 

verified if peak retention 

time criterion is satisfied 

and mass spectral 

identification is confirmed.

Identify and correct source of 

problem

16 LFSM of Field 

Sample

At low-level fortification, 

50 to 150% recovery and at 

mid-level, 70 to 130% 

LFSM method analyte recovery 

failure does not invalidate Analysis 

Batch, Extraction or Digestion 

Batch.

17 LFSMD of Field 

Sample

At low-level fortification, 

50 to 150% recovery and at 

mid-level, 70 to 130%

LFSMD method analyte recovery 

failure does not invalidate Analysis 

Batch, Extraction or Digestion 

Batch.

18 through 

28

Field Samples 12 to 

20

Positive ID of analyte is 

verified if peak retention 

time criterion is satisfied 

and mass spectral 

identification is confirmed.

Identify and correct source of 

problem

29 Close-out highlevel CCC70 to 130% Instrument maintenance followed 

by recalibration.

7.12 Exceeding the Calibration Range

The analyst must not extrapolate beyond the established calibration range, except as described for EPA 

Method 200.8 in Appendix B, Section 10.2.9. If an analyte result exceeds the range of the calibration 

curve, a sample dilution may be made. Dilute with the same solvent to match the original solvent 

composition, and if an internal standard is used, add an amount to match the original concentration in 
28

the vial. The dilution must be factored into the calculation of final concentration. The resulting data 

must be annotated as a dilution. Dilutions must be run within an Analysis Batch and count as a field 

sample. The surrogate recovery of the original injection is reported. For the analyzed dilution, report 

only method analytes that required the dilution. The associated internal standard in the dilution is 

reported.

7.13 Legal Defensibility of Data

The sample analyte result that is reported to the EPA electronic data reporting system must be legally 

defensible because results are ultimately used for regulatory determinations. EPA must be able to track

through record keeping all information that has to do with the sample for a reported result from sample 

collection to analysis. For example, EPA must have the ability to check that reagents are not expired, 

check that the correct SPE cartridges were used, and check that the associated QC samples passed 

criteria.

8 Sample Handling Requirements

Laboratory personnel must be familiar with the sample collection, preservation, and storage 

requirements. Laboratories performing UCMR 4 analyses for a large public water system (PWS) are 

responsible for communicating with the PWS and ensure their client has a clear understanding of the 

UCMR 4-specific requirements for sample collection, preservation and transportation. Note that UCMR 

4 samples must not be composited, that is, combined, mixed or blended. Samples from each sampling 

point must be collected, preserved and processed separately. Calculate final analyte recoveries based on 

the measured or weighed volume of sample (Section 8.7).

8.1 Sample Collection Time and Date

PWSs that must ship the samples for analysis should recognize that samples must be collected early 

enough in the day to allow adequate time to send these samples for overnight delivery to the 

laboratory. The PWS should avoid collecting samples on Thursday and should not collect samples on 

Friday, Saturday, or Sunday unless special arrangements have been made for the receipt of samples at 

the laboratory within 48 h of collection.

8.1.1 Sample Bottle Criteria and Sample Hold Time

The laboratory is responsible for making certain each field sample is analyzed within the required 

holding time. A list of maximum holding times, and sample bottle material, is listed in Table 11 of 

Section 8.2.5. These maximum holding times apply when field samples are properly preserved and 

stored in appropriate sample containers at appropriate temperatures. The field sample holding time 

begins on the day the sample is collected. Table 11 of Section 8.2.5 provides the temperature and 

sample bottle material criteria for UCMR 4 samples. Some UCMR 4 methods require protecting the 

sample from exposure to light. In such cases, the PWS or laboratory may use either amber sample 

bottles or clear glass bottles wrapped with foil. Laboratories are responsible for ensuring that their client 

PWSs use proper sample containers. If improper containers are used, for example, plastic bottles 

instead of glass, the laboratory should notify the PWS that a replacement sample must be collected 

using proper containers. Samples must not be analyzed if they were not shipped properly.
29

8.1.2 Table 11. Requirements for Sample Bottle Material and Sample Hold Time.

Analytical Method Sample Bottle Materials Holding Time for 

Sample (days)

EPA 200.8,ASTM D5673-10,

SM 3125

Metals

Plastic or glass bottles 28

ELISA method

Total Microcystins

TBD TBD

EPA 525.3

Pesticides

Amber glass bottles fitted with 

polytetrafluoroethylene (PTFE)-lined screw caps

preferred.

14

EPA 530

Semivolatiles

Amber glass bottles with PTFE-lined screw caps 

preferred. Clear glass bottles may be substituted if 

sample bottles are wrapped with foil, stored in 

boxes, or otherwise protected from light during 

sample shipping and storage.

14

EPA 541

Alcohols

Amber glass bottles or vials with PTFE-lined screw 

cap

28

EPA 544

Microcystins & Nodularin

Amber glass bottle with PTFE-lined screw cap 28

EPA 545

Cylindrospermopsin & 

Anatoxin-a

Amber glass bottles, at least fifty-mL, fitted with 

PTFE-lined screw caps

28

EPA 552.3

Haloacetic acids

Amber glass bottles, at least 50-mL, fitted with 

PTFE-lined screw caps

14

EPA 557

Haloacetic acids

Amber glass bottles fitted with PTFE-lined screw 

caps

14

8.2 Sample Transport and Storage

Laboratories must examine the samples when they arrive and determine if the proper shipping 

conditions were used. Samples should arrive at the laboratory packed on ice or with frozen gel packs in a 

sample bottle made of appropriate material as described in the analytical method. Samples that are 

shipped from the PWS should be sent by priority overnight delivery to the laboratory. Except for Method 

200.8, samples must be received at the laboratory within 48 h of collection and must be at 10 °C or less. 

After arrival, or within 48 h of collection, whichever is sooner, the samples must be refrigerated at 6 °C

or less. Samples received more than 48 hours after collection are valid only if they are received at ≤6°C 

and if the receiving laboratory can verify and document that they were refrigerated between collection 

and shipment.

8.2.1 Warm Weather Transport

During the summer, the ambient water temperature can be significantly above 10 °C at the time of 

collection. In such a case, samples may be iced or refrigerated for a period of time prior to shipping to 

ensure that the laboratory receipt temperature is within QC criteria. EPA suggests collecting such 

samples in the morning and refrigerating them for several hours before packing them in the cooler with 

the ice or frozen gel packs for transport.
30

8.2.2 Same Day Delivery

It is possible that water samples may arrive at the laboratory on the same business day as sample 

collection due to close proximity of a PWS to the laboratory. In such a case the sample temperature may 

not yet have stabilized to 10 °C or less when they arrive at the lab. Such samples are acceptable only if 

the samples are packed with ice or frozen gel packs immediately after collection.

8.2.3 Temperature Documentation

• Sample temperature must be checked by the receiving laboratory even if they send the sample 

on to a subcontractor laboratory; the subcontractor must also check sample temperature.

• A minimum of one bottle for every analytical method must be checked for temperature. If the 

bottle that is checked meets the temperature criterion, then the laboratory can assume that the 

other bottles for the same method also meet the temperature criterion. If the bottle that is 

checked does not meet the temperature criterion, then the sample in that bottle is invalid. The 

temperature of the other samples collected for that method should be checked to determine if 

a valid sample was received.

• All sample temperatures as well as other sample receipt parameters, such as chlorine and pH, 

must be recorded, rather than only recording non-conformances.

• A sample that contains ice inside the bottle is invalid and must be recollected.

• It is not acceptable to sample the temperature of the ice slush in the kit as a determination of 

sample temperature.

• The use of temperature blanks is not allowed unless there is a temperature blank for every 

bottle type in the kit.

• If samples are received more than 48 h after collection and meet the temperature criteria, the 

laboratory must check with the party that held the sample, for example, a subcontractor or PWS 

that sampled, to make sure that the sample was held at 10 °C, or less, for the first 48 h and 6 °C,

or less, thereafter while in their possession.

8.3 Sample Preservation

The stability of the UCMR 4 samples is dependent upon proper preservation and dechlorination. Both 

the laboratory and PWS are responsible for ensuring that the UCMR 4 samples are properly preserved 

and dechlorinated as stipulated in the analytical methods. Dechlorination and preservation are required 

at the time of sample collection. There must be clear communication between the laboratory and PWS 

that assures correct use of dechlorination agents and preservatives as specified in the method and in 

Table 12 of Section 8.3.4. If the laboratory provides bottles containing the appropriate chemicals to the 

sampler, then the sampler should be notified that the bottles cannot be rinsed or permitted to overflow 

at the time of sample collection. Further, the laboratory must adhere to any time limits stipulated in the 

analytical method that the chemicals will be stable in the sample bottle.

8.3.1 Preservation and Dechlorination Agents

For the UCMR 4 methods, the reagents in Table 12 of Section 8.3.4 serve a number of functions in the 

field sample. Acid preservation agents, such as nitric acid (pH 2), sodium bisulfate (pH 3), and potassium 

dihydrogen citrate (pH 3.8), inhibit microbial growth. Diazolidinyl urea and 2-chloroacetamide are 

microbial inhibitors that are still effective at pH 7. Ascorbic acid and sodium sulfite are dechlorination 

agents. Ammonium chloride forms a chloramine residual in chlorinated finished water that reduces 

oxidative power of the chlorination to an extent that analytes in Methods 552.3 and 557 are not 

affected, but the chloramine residual still has an anti-microbial effect. Ethylenediaminetetraacetic acid 
31

trisodium salt isolates metals that might otherwise promote reactions that degrade analytes. Trizma at

pH 7.0 is a commercial buffer mixture of tris(hydroxymethyl)aminomethane (Tris) and Tris 

hydrochloride. For EPA Methods 530 and 544, an alternative to Trizma, pH 7.0, is to weigh out the 

individual compounds, which are Tris, 0.47g/L, and Tris hydrochloride, 7.28 g/L.

8.3.2 Checking Samples for Proper Preservation

On same day of sample receipt, or within 48-h of collection, laboratories should verify preservation and 

dechlorination of each sample by conducting the appropriate check listed in Table 12 of Section 8.3.4. 

These checks must be performed at the laboratory where the sample will be processed. If the criteria 

are not met, the samples must not be analyzed, and a new sample must be collected from the PWS.

8.3.3 Verification of pH and Absence of Free Chlorine

Verify pH with either a standard pH meter or a test strip. The verification of the absence of free chlorine 

is qualitative, provided the laboratory can measure the presence of free chlorine at and above 0.1 mg/L. 

Note that a small aliquot of the sample should be used to test pH and chlorine content. In order to 

prevent sample contamination, probes and test strips should not be placed into the bulk sample bottle.

When a positive free chlorine result occurs, recheck with a test strip of a second method, such as the 

free chlorine DPD method. Be sure to collect enough sample volume to account for the free chlorine 

tests and any other measurement, such as for pH.

8.3.4 Table 12. Sample Preservation and Dechlorination Agents; Acceptance Criteria

Minimum weights and volumes are shown. Ten percent over the given weight or volume is acceptable.

Analytical Method Chemical and Concentration Sample Check or Criteria

EPA 200.8,

ASTM D5673-10,

SM 3125

Metals

Two mL of concentrated nitric acid per liter

of sample. Acid may be added in field or in 

lab prior to analysis. If acid is added at lab, 

sample must be held for sixteen hours and 

pH verified again prior to processing

pH 2 or less

EPA ELISA method

Total Microcystins

TBD TBD

EPA 525.3

Pesticides

Ascorbic acid, 0.10 g/L

Ethylenediaminetetraacetic acid, 0.35 g/L

Potassium dihydrogen citrate, 0.4 g/L

Absence of free chlorine, 

less than 0.1 mg/L

EPA 530

Semivolatiles

Trizma, 7.75 g/L

Ascorbic acid, 0.10 g/L

Ethylenediaminetetraacetic acid, 0.35 g/L

Diazolidinyl urea, 1.0 g/L

Absence of free chlorine, 

less than 0.1 mg/L and pH

about 7

EPA 541

Alcohols

Sodium sulfite, 50 mg/mL

Sodium bisulfate, 1.0 g/L

Absence of free chlorine, 

less than 0.1 mg/L and pH

less than 3

EPA 544

Microcystins & 

Nodularin

pH 7.0 Trizma, 7.75 g/L

2-Chloroacetamide, 2 g/L

Ascorbic Acid, 0.10 g/L

Ethylenediaminetetraacetic acid trisodium 

salt, 0.35 g/L

Absence of free chlorine, 

less than 0.1 mg/L

EPA 545

Cylindrospermopsin 

& Anatoxin-a

Ascorbic acid, 0.10 g/L

Sodium bisulfate, 1.0 g/L

Absence of free chlorine, 

less than 0.1 mg/L
32

Analytical Method Chemical and Concentration Sample Check or Criteria

EPA 552.3

Haloacetic acids

Ammonium chloride, 0.10 g/L Absence of free chlorine, 

less than 0.1 mg/L

EPA 557

Haloacetic acids

Ammonium chloride, 0.10 g/L Absence of free chlorine, 

less than 0.1 mg/L

8.4 Extract Holding Times and Temperatures

The laboratory is responsible for ensuring each sample extract is analyzed within the required holding 

time. A list of maximum holding times and temperature specifications for extracts are listed in Table 13 

of Section 8.4.3. The sample extract holding time begins on the day the sample extraction was begun.

8.4.1 Table 13. Maximum Holding Time and Holding Time Temperature for Extracts.

Analytical Method Extract Holding Time 

(days)

Temperature Specification for Extracts

EPA 200.8, ASTM D5673-10,

SM 3125

Metals

28 recommended for 

digested samples

No temperature specification

EPA ELISA method

Total Microcystins

NA NA

EPA 525.3

Pesticides

28 –5 °C or lower.

EPA 530

Semivolatiles

14 –5 °C or lower.

EPA 541

Alcohols

28 –10 °C or lower

EPA 544

Microcystins & Nodularin

28 –4 °C or lower.

EPA 545

Cylindrospermopsin & 

Anatoxin-a

NA NA

EPA 552.3

Haloacetic acids

28 –10 °C or lower.

EPA 557

Haloacetic acids

NA NA

8.5 Invalid Sample

If a UCMR 4 sample is not extracted or analyzed within the times specified in sample hold times of Table 

11 of Section 8.2.5 and the extract hold times and temperatures of Table 13 of Section 8.4.3, then the 

data for the sample must not be reported. The laboratory should indicate to the PWS that the sample 

was invalidated due to a holding time problem, and the PWS should resample. Metals samples that are 

not digested within the 28 day holding time should not be discarded or invalidated. Metals samples can 

be digested up to 6 months after collection. The laboratory should inform EPA of metals samples that 

are digested more than 28 days after collection.

8.6 Method Information Concerning Collection and Holding

The published UCMR 4 analytical methods provide additional information concerning recommended 

sample collection and holding procedures for samples. These procedures must be observed for UCMR 4 

samples.
33

8.7 Sample Volume

The volume of sample processed must be quantitatively measured, and the measured volume must be 

documented on the preparation/digestion/extraction batch bench sheet. If volume is determined by 

weighing the sample bottle before and after removing the volume for processing, then the before and 

after weights must be recorded. If there is not enough volume in a method-specific sample bottle, and 

multiple bottles of sample were collected from the same location and for the same method and meet 

the sample receipt acceptance criteria, then the laboratory may combine the volumes to obtain enough 

volume for processing. If the volume of sample that is processed varies from the method-specified 

volume by more than 5%, then sample results must be adjusted accordingly. Assume a sample density of 

1.00 g/mL. The sample volume will be used in the calculation of analyte sample concentration.

8.8 Laboratory Errors or Sampling Deviations

If a sampling or laboratory error occurs which precludes the reporting of valid data, a resample must be 

collected within 30 days of the PWS being notified of the error. This resampling is not for confirmation 

sampling, but rather to correct the sampling or laboratory error. Only method analytes that failed in the 

original analysis need to be reported in the resample. If resampling cannot be performed, then the PWS 

should be instructed to notify EPA’s UCMR Sampling Coordinator via e-mail at 

UCMR_Sampling_Coordinator@epa.gov.

8.8.1 Matrix Interference in Field Sample

If matrix interference is suspected in a field sample, reanalyze the sample. If the result is similar, collect 

enough volume to run an LFSM, an LFSMD, and an unfortified sample and process to confirm matrix 

interference. Provide argument for matrix interference to EPA and ask for a determination on how to 

proceed.

9 Uploading Data to EPA database

Any deviations from the standard procedures for processing, analyzing, and generating results for field 

samples must be approved by EPA prior to uploading the data to the EPA electronic data reporting 

system. EPA anticipates laboratories will be required to submit quality control information associated 

with sample results to the EPA electronic data reporting system. EPA will issue instructions for 

submitting data to the EPA electronic data reporting system in a separate document.

9.1 Table 14. Unregulated Contaminant Monitoring Reporting Requirements

Data element Definition

1. Public Water 

System Identification 

(PWSID) Code

The code used to identify each PWS. The code begins with the standard 2-

character postal State abbreviation or Region code; the remaining 7 numbers 

are unique to each PWS in the State. The same identification code must be 

used to represent the PWS identification for all current and future UCMR 

monitoring.

2. Public Water 

System Name

Unique name, assigned once by the PWS.

3. Public Water 

System Facility 

Identification Code

An identification code established by the State or, at the State’s discretion, by 

the PWS, following the format of a 5-digit number unique within each PWS 

for each applicable facility (i.e., for each source of water, treatment plant, 

distribution system, or any other facility associated with water treatment or 
34

Data element Definition

delivery). The same identification code must be used to represent the facility 

for all current and future UCMR monitoring.

4. Public Water 

System Facility Name

Unique name, assigned once by the PWS, for every facility ID (e.g., Treatment 

Plant).

5. Public Water 

System Facility Type

That code that identifies that type of facility as either: 

CC = consecutive connection

DS = distribution system

IN = source water intake

SS = sampling station

TP = treatment plant

OT = other

6. Water Source Type The type of source water that supplies a water system facility. Systems must 

report one of the following codes for each sampling location: 

SW = surface water (to be reported for water facilities that are served all 

or in part by a surface water source at any time during the twelve-month 

period). 

GW = ground water (to be reported for water facilities that are served 

entirely by a ground water source).

GU = ground water under the direct influence of surface water (to be 

reported for water facilities that are served all or in part by ground water 

under the direct influence of surface water at any time during the twelvemonth sampling period), and are not served at all by surface water during 

this period.

7. Sampling Point 

Identification Code

An identification code established by the State, or at the State’s discretion, by 

the PWS, that uniquely identifies each sampling point. Each sampling code 

must be unique within each applicable facility, for each applicable sampling 

location (i.e., entry point to the distribution system, source water intake or 

distribution system sample at maximum residence time). The same 

identification code must be used to represent the sampling location for all 

current and future UCMR monitoring.

8. Sampling Point 

Name

Unique sample point name, assigned once by the PWS, for every sample point 

ID (e.g., Entry Point).

9. Sampling Point 

Type Code

A code that identifies the location of the sampling point as either: 

SR = source water taken from plant intake; untreated water entering the 

water treatment plant (i.e., a location prior to any treatment).

EP = entry point to the distribution system. 

MR = distribution system sample at maximum residence time.

10. Disinfectant Type All of the primary disinfectants/oxidants that have been added in the 

treatment plant to the water being sampled. To be reported by systems for 

each sampling point.

PEMB = Permanganate (applied before SR sample location)

PEMA = Permanganate (applied after SR sample location) 

HPXB = Hydrogen peroxide (applied before SR sample location)

HPXA = Hydrogen peroxide (applied after SR sample location)

CLGA = Gaseous chlorine

CLOF = Offsite Generated Hypochlorite (stored as a liquid form)
35

Data element Definition

CLON = Onsite Generated Hypochlorite

CAGC = Chloramine (formed from gaseous chlorine)

CAOF = Chloramine (formed from offsite hypochlorite)

CAON = Chloramine (formed from onsite hypochlorite)

CLDB = Chlorine dioxide (applied before SR sample location)

CLDA = Chlorine dioxide (applied after SR sample location)

OZON = Ozone

ULVL = Ultraviolet light

OTHD = All other types of disinfectant/oxidant

NODU = No disinfectant/oxidant used

11. Treatment 

Information

Treatment information associated with the water being sampled.

CON = Conventional (non-softening)

SCO = Softening conventional

RBF = River bank filtration

PSD = Pre-sedimentation

INF = In-line filtration

DFL = Direct filtration

PCF = Precoat filtration

SSF = Slow sand filtration

BIO = Biological filtration

REC = Reactor clarification (e.g. solids contact clarification, slurry 

recirculation clarification, Aciflo®) 

SBC = Sludge blanket clarification (e.g. Pulsator®, Super Pulsator®, contact 

adsorption clarifiers, floc-blanket clarifiers)

ADC = Adsorption clarification (contact adsorption clarification)

UTR = Unfiltered treatment

PAC = Application of powder activated carbon

GAC = Granular activated carbon (not part of filters in CON, SCO, INF, DFL,

or SSF)

AIR = Air stripping (packed towers, diffused gas contactors)

POB = Pre-oxidation/disinfection with chlorine (applied before SR sample 

location)

POA = Pre-oxidation/disinfection with chlorine (applied after SR sample 

location)

MFL = Membrane filtration

IEX = Ionic exchange

UVT = Ultraviolet light

AOX = Advanced oxidation (ultraviolet light with hydrogen peroxide and/or 

ozone)

DAF = Dissolved air floatation

CWL = Clear well/finished water storage without aeration

CWA = Clear well/finished water storage with aeration

ADS = Aeration in distribution system (localized treatment)

OTH = All other types of treatment

NTU = No treatment used

12. Disinfectant 

Residual Type

Secondary disinfectant type added in the distribution system for each finished 

water sample.
36

Data element Definition

CL2 = Chlorine (i.e., originating from addition of free chlorine only)

CLM = Chloramines (originating from with addition of chlorine and 

ammonia or pre-formed chloramines) 

CAC = Chlorine and chloramines (if being mixed from chlorinated and 

chloraminated water)

NOD = No disinfectant residual

13. Sample Collection 

Date

The date the sample is collected, reported as 4-digit year, 2-digit month, and 

2-digit day (YYYY/MM/DD).

14. Sample 

Identification Code

An alphanumeric value up to 30 characters assigned by the laboratory to 

uniquely identify containers, or groups of containers, containing water 

samples collected at the same sampling location for the same sampling date.

15. Contaminant The unregulated contaminant for which the sample is being analyzed.

16. Analytical 

Method Code 

The identification code of the analytical method used.

17. Extraction Batch 

Identification Code

Laboratory assigned extraction batch ID. Must be unique for each extraction 

batch within the laboratory for each method. For CCC samples report the 

Analysis Batch Identification Code as the value for this field. For methods 

without an extraction batch, leave this field null.

18. Extraction Date Date for the start of the extraction batch (YYYY/MM/DD). For methods 

without an extraction batch, leave this field null.

19. Analysis Batch 

Identification Code

Laboratory assigned analysis batch ID. Must be unique for each analysis batch 

within the laboratory for each method.

20. Analysis Date Date for the start of the analysis batch (YYYY/MM/DD).

21. Sample Analysis 

Type

The type of sample collected and/or prepared, as well as the fortification 

level. Permitted values include: 

CF = concentration fortified; the concentration of a known contaminant 

added to a field sample reported with sample analysis types LFSM, LFSMD, 

LFB, CCC and QCS.

CCC = continuing calibration check; a calibration standard containing the 

contaminant, the internal standard, and surrogate analyzed to verify the 

existing calibration for those contaminants. 

FS = field sample; sample collected and submitted for analysis under this 

rule. 

IS = internal standard; a standard that measures the relative response of 

contaminants.

LFB = lab fortified blank; an aliquot of reagent water fortified with known 

quantities of the contaminants and all preservation compounds.

LRB = lab reagent blank; an aliquot of reagent water treated exactly as a 

field sample, including the addition of preservatives, internal standards, 

and surrogates to determine if interferences are present in the laboratory, 

reagents, or other equipment. 

LFSM = laboratory fortified sample matrix; a UCMR field sample with a 

known amount of the contaminant of interest and all preservation 

compounds added. 

LFSMD = laboratory fortified sample matrix duplicate; duplicate of the 

laboratory fortified sample matrix. 
37

Data element Definition

QCS = quality control sample; a sample prepared with a source external to 

the one used for initial calibration and CCC. The QCS is used to check 

calibration standard integrity.

QH = quality HAA; HAA sample collected and submitted for quality control 

purposes. 

SUR = surrogate standard; a standard that assesses method performance 

for each extraction.

22. Analytical 

Results—Sign

A value indicating whether the sample analysis result was: 

(<) “less than” means the contaminant was not detected, or was detected 

at a level below the Minimum Reporting Level. 

(=) “equal to” means the contaminant was detected at the level reported 

in “Analytical Result— Measured Value.”

23. Analytical 

Result—Measured 

Value

The actual numeric value of the analytical results for: field samples; 

laboratory fortified matrix samples; laboratory fortified sample matrix 

duplicates; and concentration fortified.

24. Additional Value Represents the true value or the fortified concentration for spiked samples 

for QC Sample Analysis Types (CCC, EQC, LFB, LFSM and LFSMD). For Sample 

Analysis Type FS and LRB and for IS and surrogate QC Contaminants, leave 

this field null. 

25. Laboratory 

Identification Code

The code, assigned by EPA, used to identify each laboratory. The code begins 

with the standard two-character State postal abbreviation; the remaining five 

numbers are unique to each laboratory in the State.

26. Sample Event 

Code

A code assigned by the PWS for each sample event. This will associate 

samples with the PWS monitoring plan to allow EPA to track compliance and 

completeness. Systems must assign the following codes: 

SEC1, SEC2, SEC3, SEC4, SEC5, SEC6, SEC7 and SEC8 - represent samples 

collected to meet UCMR Assessment Monitoring requirements for 

cyanotoxins; where “SEC1” represents the first sampling period, “SEC2” the 

second period and so forth, for all eight sampling events. 

SEA1, SEA2, SEA3 and SEA4 - represent samples collected to meet UCMR 

Assessment Monitoring requirements for the additional chemicals; where 

“SEA1” and “SEA2” represent the first and second sampling period for all 

water types; and “SEA3” and “SEA4” represent the third and fourth sampling 

period for SW and GU sources only.

9.2 HAAs Reported as Groups

The proposed contaminant list for UCMR 4 presents the Haloacetic Acids (HAAs) as groups. Since no 

method currently exists to analyze samples for the HAAs in groups, laboratories are required to report 

HAA results to the EPA electronic data reporting system as individual analytical results for each HAA, 

along with the associated batch QC. HAAs will be grouped according to Table 15 (Section 9.2.1).
38

9.2.1 Table 15. Haloacetic Acid Groups

1-Contaminant 2-CAS 

Registry 

Number

3-Analytical 

Methodsa

4-Minimum 

Reporting 

Level b

5-HAA6Br 

Group

6-HAA9 

Group

7-HAA5 

Group

Bromochloroacetic 

acid (BCAA)

5589-96-8 EPA 552.3 or 

EPA 557

0.3 μg/L HAA6Br HAA9 ---

Bromodichloroacetic 

acid (BDCAA)

71133-14-7 EPA 552.3 or 

EPA 557

0.5 μg/L HAA6Br HAA9 ---

Chlorodibromoacetic 

acid (CDBAA)

5278-95-5 EPA 552.3 or 

EPA 557

0.3 μg/L HAA6Br HAA9 ---

Tribromoacetic acid 

(TBAA)

75-96-7 EPA 552.3 or 

EPA 557

2.0 μg/L HAA6Br HAA9 ---

Monobromoacetic 

acid (MBAA)

79-08-3 EPA 552.3 or 

EPA 557

0.3 μg/L HAA6Br HAA9 HAA5

Dibromoacetic acid 

(DBAA)

631-64-1 EPA 552.3 or 

EPA 557

0.3 μg/L HAA6Br HAA9 HAA5

Dichloroacetic acid 

(DCAA)

79-43-6 EPA 552.3 or 

EPA 557

0.2 μg/L --- HAA9 HAA5

Monochloroacetic 

acid (MCAA)

79-11-8 EPA 552.3 or 

EPA 557

2.0 μg/L --- HAA9 HAA5

Trichloroacetic acid 

(TCAA)

76-03-9 EPA 552.3 or 

EPA 557

0.5 μg/L --- HAA9 HAA5

10 References

Revisions to the Unregulated Contaminant Monitoring Rule (UCMR 4) for Public Water Systems. 

Ohio EPA Total (Extracellular and Intracellular) Microcystins - ADDA by ELISA Analytical Methodology, 

Version 2.0, January 2015

ASTM Standard D5673-10. Standard Test Method for Elements in Water by Inductively Coupled 

Plasma-Mass Spectrometry. American Society for Testing and Materials (ASTM), West Conshohocken, 

PA. 2005.

EPA Method 200.8. Determination of Trace Elements in Waters and Wastes by Inductively Coupled 

Plasma–Mass Spectrometry, Revision 5.4, EMMC Version. Environmental Monitoring Systems 

Laboratory, Office of Research and Development, U.S.EPA, Cincinnati, Ohio 45268.

EPA Method 525.3. Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase 

Extraction and Capillary Column Gas Chromatography-Mass Spectrometry (GC-MS)), Version 1.0, 

February 2012. EPA/600/R-12/101. National Exposure Research Laboratory, Office of Research and 

Development, U.S.EPA, Cincinnati, Ohio 45268.

EPA Method 530. Determination of Select Semivolatile Organic Chemicals in Drinking Water by Solid 

Phase Extraction and Gas Chromatography-Mass Spectrometry (GC-MS), Version 1.0, January 2015. EPA

Document #600/R-14/442. National Exposure Research Laboratory, Office of Research and 

Development, U.S.EPA, Cincinnati, Ohio 45268.

EPA Method 541. Determination of 1-Butanol, 1,4-Dioxane, 2-Methoxymethanol and 2-Propen-1-ol, in 

Drinking Water By Solid Phase Extraction and Gas Chromatography-Mass Spectrometry, Version 1.0, 

November 2015, EPA Document #815-R-15-011. Technical Support Center, Standards and Risk 

Management Division, Office of Ground Water and Drinking Water, U.S.EPA, Cincinnati, Ohio 45268.
39

EPA Method 544. Determination of Microcystins and Nodularin in Drinking Water by Solid Phase 

Extraction and Liquid Chromatography/Mass Spectrometry (LC/MS/MS), Version 1.0, February 2015. EPA

Document #600/R-14/474. National Exposure Research Laboratory, Office of Research and 

Development, U.S.EPA, Cincinnati, Ohio 45268.

EPA Method 545. Determination of Cylindrospermopsin and Anatoxin-a in Drinking Water by Liquid 

Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS-MS), Version 1.0,

EPA Document #815-R-15-009. Technical Support Center, Standards and Risk Management Division, 

Office of Ground Water and Drinking Water, U.S.EPA, Cincinnati, Ohio 45268.

EPA Method 552.3. Determination of Haloacetic acid Dalapon in Drinking Water by Liquid-Liquid 

Microextraction , Derivatization, and Gas Chromatography with Electron Capture Detection, Version 1.0. 

EPA Document #815-B-03-002. Technical Support Center, Standards and Risk Management Division, 

Office of Ground Water and Drinking Water, U.S.EPA, Cincinnati, Ohio 45268.

EPA Method 557. Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion 

Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS), Version 1.0, 

September 2009. EPA Document #815-B-09-012. Technical Support Center, Standards and Risk 

Management Division, Office of Ground Water and Drinking Water, U.S.EPA, Cincinnati, Ohio 45268.

EPA Requirements for Quality Assurance Project Plans. EPA QA/R-5, March 2001, U.S.EPA Document 

#EPA/240/B-01/003. Office of Environmental Information, U.S.EPA, Washington, DC 20460.

Technical Basis for the Lowest Concentration Minimum Reporting Level Calculator. December 

2010. EPA Document #815-R-11-001. Technical Support Center, Standards and Risk Management 

Division, Office of Ground Water and Drinking Water, U.S.EPA, Cincinnati, Ohio 45268.

SM Method 3125. Metals by Inductively Coupled Plasma/Mass Spectrometry in Standard Methods for 

the Examination of Water and Wastewater, 21st Ed. 2005, Prepared and Published Jointly by APHA, 

AWWA, and WEF, Eaton, A.D., Clesceri, L.S., Rice, E.W., Greenberg, A.E., Eds.; American Public Health 

Association, 800 I Street, NW, Washington, DC 20001-3710.

U.S. Geological Survey, Processing of water samples (ver. 2.2). U.S. Geological Survey Techniques of 

Water-Resources Investigations, Book 9, Chapter A5 Section 5.6.1.F, "Wastewater, pharmaceutical, and 

antibiotic compounds", April 2004.

11 Appendix A: Requirements for Water Quality Parameters and 

Indicators

11.1 Total Organic Carbon (TOC) and Bromide

Water systems analyzing samples for bromide or total organic carbon as required in association with 

HAA results should follow the procedure described in Section 2.1 and Section 2.2.1. This entails 

contacting the UCMR Laboratory Approval Coordinator to register and submitting paperwork that 

certifies your primacy state permits you to submit data for any of the water quality parameters, as 

SDWA compliance data, under Stage 2 DBP Rule.

11.2 Temperature and pH Data for ELISA method

EPA anticipates having an EPA ELISA method available by the publication of the final rule and anticipates 

that this method will be similar to the Ohio EPA methodology. At this time EPA expects to have water 

systems report data for temperature and pH into the EPA electronic data reporting system for samples 
40

associated with the ELISA method. Monitoring includes measuring for water temperature using one of 

the following methods: SM 2550 or SM 2550-00. Monitoring also includes measuring for pH using one of 

the following methods: EPA Method 150.1 and 150.2, ASTM D1293-12, SM 4500-H+ B, and SM 4500-H+ 

B-00.

12 Appendix B: Requirements for UCMR 4 Method 200.8 Analysis

12.1 Isotopes and Internal Standards

For the analytes of Table 14, Section 10.3, monitor all of the isotopes listed in the second and fourth 

columns. Report using the isotopes listed in the fifth column using the Elemental & Molecular Correction 

Equations listed in the sixth column. These Elemental and Molecular Correction Equations in Table 14, 

Section 10.3 must be used. The internal standards listed are in order of suggested use, but any of the 

internal standards listed in the table are acceptable.

12.2 Additions and Exceptions to Method 200.8 for UCMR 4

Follow EPA Method 200.8 Revision 5.4 for Total Recoverable Analytes in Aqueous Samples with the 

additions and exceptions given in this section.

12.2.1 Sample Container

In Method 200.8, Section 8.0, sample container can be plastic or glass and sample size is one-hundred 

mL.

12.2.2 Turbidity

In Method 200.8, Section 11.2.2, samples must be digested regardless of turbidity.

12.2.3 Do Not Use Hydrochloric Acid

In Method 200,8 Section 11.2.3, omit the use of Hydrochloric Acid.

12.2.4 Do Not Adjust Chloride Concentration

Omit Method 200.8, Section 11.2.8 that concerns adjustment of chloride concentration.

12.2.5 Cell Type

A collision cell or dynamic reaction cell or a dynamic reaction cell technology may NOT be used.

12.2.6 Nitric Acid

Standards as well as the IS stock solution and calibration blanks must be prepared in one percent nitric 

acid. Two percent nitric acid is not acceptable.

12.2.7 Calibration Points

If five calibration points are required, the calibration blank does not count towards those five points. A 

calibration curve for Method 200.8 must contain a minimum of five standards that contain the analyte 

in addition to the calibration blank.

12.2.8 Calibration fit and regression

Linear calibration, not forced through zero, and with no weighting, must be used. 

12.2.9 Linear Dynamic Range Check

Check the linear dynamic range (LDR) daily, when the method is used. The LDR check can be performed 

at any point in the Analysis Batch. An LDR check does not have to be performed on the standard with 

the highest concentration.
41

12.3 Table 16. Determination of Metals for UCMR 4 by EPA Method 200.8 Rev. 5.4

Analytes Natural 

Isotopes 

(monitor all 

of these)

% Relative 

Abundance

Additional 

Isotopes to 

Monitor

Isotope 

to Report

Elemental & Molecular 

Correction Equations

Germanium 72

74

27.4

36.5

--- 74 TBD

Manganese 55 100 --- 55 (1.000) (55C)

Internal standard: 

Scandium (SC), 

45 100 --- 45 (1.000) (55C), 

background molecular 

ions may interfere

Internal standard: 

Indium (In)

113 (Cd)

115 (Sn)

4.3

95.7

106, 108, 

111, 114, 

118, 120

115 [(1.000) (

115C) – (0.016) 

(

118C)]

If Tin is present, use the 

isobaric elemental 

correction for Tin.

Internal standard: 

Terbium (Tb)

159 100 --- 159 (1.000) (159C)

13 Appendix C: LCMRLs and MRLs for UCMR 4 Target Analytes 

There were sixteen different laboratories that participated in the LCMRL studies and that generated the 

data in the following tables.

13.1 Table 17: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 200.8 (SIM).

Contaminants CASRN LCMRL

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL

(μg/L)

Germanium 7440-56-4 0.027 0.14 0.083 0.27

Manganese 7439-96-5 0.069 0.24 0.31 0.34

13.2 Table 18: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 525.3 (SIM).

Contaminants CASRN LCMRL

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL

(μg/L)

Chlorpyrifos 2921-88-2 0.017 0.023 0.026 0.029

Dimethipin 55290-64-7 0.072 0.12 0.082 0.12

Ethoprop 13194-48-4 0.026 0.012 0.011 0.027

alpha-Hexachlorocyclohexane 319-84-6 0.0069 0.0023 0.0064 0.010

Hexazinone 51235-04-2 0.074 0.0053 0.013 0.046

Oxyfluorfen 42874-03-3 0.015 0.011 0.13 0.046

cis- and trans-Permethrin 52645-53-1 0.015 NA 0.031 0.036

Profenofos 41198-08-7 0.16 0.012 0.098 0.21

Tebuconazole 107534-96-3 0.061 0.0078 0.16 0.17

Tribufos 78-48-8 0.020 0.072 0.037 0.061

Vinclozolin 50471-44-8 0.022 0.0036 0.010 0.020

13.3 Table 19: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 530.

Contaminants CASRN LCMRL

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL

(μg/L)

Butylated hydroxyanisole (BHA) 25013-16-5 0.013 0.0036 0.031 0.0057 0.028
42

Contaminants CASRN LCMRL

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL

(μg/L)

Dimethipin 55290-64-7 0.0028 0.077 0.010 0.0097 0.021

Quinoline 91-22-5 0.0046 0.0032 0.026 0.0014 0.013

o-Toluidine 95-53-4 0.0028 0.0060 0.0018 0.0018 0.0061

13.4 Table 20: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 541.

Contaminants CASRN LCMRL

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL

(μg/L)

1-Butanol 71-36-3 0.44 0.61 2.0 0.94 1.5

2-Methoxyethanol 109-86-4 0.37 0.30 0.24 --- 0.38

2-Propen-1-ol 107-18-6 0.30 0.17 0.23 0.43 0.46

13.5 Table 21: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 544.

Contaminants CASRN LCMRL

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL

(μg/L)

Microcystin-LA 96180-79-9 0.0029 0.0090 0.0023 0.0076

Microcystin-LF 154037-70-4 0.0035 0.0025 0.0049 0.0060

Microcystin-LR 101043-37-2 0.0066 0.013 0.015 0.016

Microcystin-LY 123304-10-9 0.0046 0.0029 0.014 0.0088

Microcystin-RR 111755-37-4 0.0056 0.00093 0.0026 0.0054

Microcystin-YR 101064-48-6 0.022 0.0043 0.0037 0.020

Nodularin-R 118399-22-7 0.0073 0.0020 0.0026 0.0047

13.6 Table 22: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 545.

Contaminants CASRN LCMRL

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL

(μg/L)

Anatoxin-a 64285-06-9 0.018 0.0027 0.0064 0.018 0.021

Cylindrospermopsin 143545-90-8 0.063 0.0042 0.046 0.038 0.083

13.7 Table 23: LCMRLs and MRLs for UCMR 4 analytes by EPA Method 552.3.

Analytes LCMRL 

(μg/L)

LCMRL 

(μg/L)

LCMRL 

(μg/L)

MRL 

(μg/L)

Monochloroacetic acid 3.0 0.42 0.43 1.6

Dichloroacetic acid 0.075 0.12 0.098 0.17

Trichloroacetic acid 0.29 0.42 0.28 0.43

Monobromoacetic acid 0.13 0.19 0.14 0.24

Dibromoacetic acid 0.10 0.44 0.58 0.30

Bromochloroacetic acid 0.075 0.26 0.58 0.24

Bromodichloroacetic acid 0.18 0.37 0.17 0.41

Chlorodibromoacetic acid 0.10 0.23 0.091 0.24

Tribromoacetic acid 0.57 0.68 1.9 1.7