United States
   Environmental Protection
Response Protocol Toolbox:
Planning for and Responding to
Drinking Water Contamination
Threats and Incidents

Interim Final - December 2003

Module 4:
Analytical Guide

            Response Protocol Tool box:
           Planning for and Responding to
Drinking Water Contamination Threats and Incidents

             Module 4: Analytical Guide
                  Interm Final - December 2003
                       Threat Warning
                     Initial Threat Evaluation
                     Immediate Operational
                       Response Actions
                    Site Characterization and
                     Public Health Response
                       Sample Analysis
                         Is Incident
                    Remediation and Recovery

                                                       MODULE 4: Analytical Guide


Module 1: Water Utility Planning Guide (December 2003)
Module 1  provides a brief discussion of the nature of the contamination threat to the
public water supply.  The module also describes the planning activities that a utility
may undertake to prepare for response to contamination threats and incidents.

Module 2: Contamination Threat Management Guide (December 2003)
Module 2 presents the overarching framework for management of contamination
threats to the drinking water supply.  The threat management process involves two
parallel and interrelated activities: 1) evaluating the threat, and 2) making decisions
regarding appropriate actions to take in response to the threat.

Module 3: Site Characterization and Sampling Guide (December 2003)
Module 3 describes the site characterization process in which information is gathered
from the site of a suspected contamination incident at a drinking water system.  Site
characterization activities include the site investigation, field safety screening, rapid
field testing of the water, and sample collection.

Module 4: Analytical Guide (December 2003)
Module 4 presents an approach to the analysis of samples collected from the site of a
suspected contamination incident.  The purpose of the Analytical Guide is not to
provide a detailed protocol. Rather, it describes a framework for developing an
approach for the analysis of water samples that may contain an unknown contaminant.
The framework is flexible and will allow the approach to be crafted based on the
requirements of the specific situation. The framework is also designed to promote the
effective and defensible performance of laboratory analysis.

Module 5: Public Health Response Guide (available March 2004)
Module 5 deals with the public health response measures that would potentially be
used to minimize public exposure to potentially contaminated water.  It discusses the
important issue of who is responsible for making the decision to initiate public health
response actions, and considers the role of the water utility in this decision process.
Specifically, it examines the role of the utility during a public health response action,
as well as the interactions between the utility, the drinking water primacy agency, the
public health community, and other parties with a public health mission.

Module 6: Remediation and Recovery Guide (available March 2004)
Module 6 describes the planning and implementation of remediation and recovery
activities that would be necessary following a confirmed contamination incident.  The
remediation process involves a sequence of activities, including: system
characterization; selection of remedy options; provision of an alternate drinking water
supply during remediation activities; and monitoring to demonstrate that the system
has been remediated.  Module 6 describes the types of organizations that would likely
be involved in this stage of a response,  and the utility's role during remediation and
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                              TABLE OF CONTENTS

    1.2.1   SAFETY	16
    1.2.2   ANALYTICAL GOALS	17


  3.1    SAFETY	26

  4.2    SAMPLING	40



        "UNKNOWNS"	55

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    6.4.1   VOLATILES (ORGANIC)	59
    6.4.7   CYANIDES	63
    6.4.8   RADIONUCLIDES	64










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          AND SELECT AGENTS	97


          CONTAMINANTS	53
          CONTAMINANTS	57
          GROUPS	89
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The mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
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A A           Atomic absorption
AMDIS       Automated mass spectral deconvolution and identification system
AOAC        Association of Analytical Communities (formerly Association of Official Analytical
APCI         Atmospheric pressure chemical ionization
APHL         Association of Public Health Laboratories
API           Atmospheric pressure ionization
ASTM        American Society for Testing and Materials
BSL          Biosafety level
BT           Biological terrorism
CDC          Centers for Disease Control
CLIA         Clinical Laboratory Improvement Amendments
CVAA        Cold-vapor atomic absorption
CW           Chemical warfare
CWA         Clean Water Act
CWC         Chemical Weapons Convention
DNA          Deoxyribonucleic  acid
DOD          Department of Defense
DOE          Department of Energy
DOJ          Department of Justice
DOT          Department of Transportation
ELCD         Electrolytic conductivity detector
EPA          Environmental Protection Agency
ESI           Electrospray ionization
ETV          Environmental Technology Verification
FA           Immunofluorescence assay microscopy
FBI           Federal Bureau of Investigation
FDA          Food and Drug Administration
FEMA        Federal Emergency Management Agency
FERN         Food Emergency Response Network
FRMAC       Federal Radiological Management Center
GC           Gas chromatography
GFAA        Graphite furnace atomic absorption
HASP         Health and safety plan
HazMat       Hazardous materials
HHS          Health and Human Services
HPLC         High performance liquid chromatography
HRMS        High resolution mass spectrometry
1C            Ion chromatography
ICAP         Inductively coupled argon plasma
ICP-AES      Inductively coupled plasma atomic emission spectroscopy
ICP-MS       Inductively coupled plasma mass spectrometry
ICP-OES      Inductively coupled plasma optical emission spectroscopy
ICR           Information Collection Rule
IFA           Immunofluorescence assay microscopy
IMS           Immunomagnetic separation
IOC           Intergovernmental Oceanographic Commission
ISE           Ion-selective electrode
ISO           International Organization for Standardization
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LC           Liquid chromatography
LLE          Liquid-liquid extraction
LRN          Laboratory Response Network
MARLAP     Multi-Agency Radiological Laboratory Analytical Protocols
MCL          Maximum Contaminant Level
MeV          Megaelectron volts
MS           Mass spectrometry
MWCO       Molecular weight cut-off
NEMI         National Environmental Methods Index
NIST         National Institute of Standards and Technology
NRC          National Research Council
ORD          Office  of Research and Development
OSHA        Occupational Safety and Health Administration
OSW         Office  of Solid Waste
OW          Office  of Water
PCR          Polymerase chain reaction
PDA          Photodiode array detector
PID          Photoionization detector
PPE          Personal protective equipment
PSI           Pounds per square inch
QA           Quality assurance
QC           Quality control
RF           Response factor
RIFA         Radioimmunofocus assay
RNA          Ribonucleic acid
RT-PCR      Reverse Transcriptase-PCR
SDWA        Safe Drinking Water Act
SM           Standard Methods for the Analysis of Water and Waste water
SOP          Standard operating procedure
SPE          Solid-phase extraction
SPME         Solid-phase microextraction
SQM          Semi-quantitative mode
TBD          To be determined
UCMR        Unregulated Contaminant Monitoring Rule
URL          Uniform Resource Locator
USAMRIID   United States Army Medical Research Institute of Infectious Diseases
USDA        United States Department of Agriculture
UV           Ultraviolet
VEE          Venezuelan equine encephalitis virus
VHP          Viral hemorrhagic fever
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Definitions in this glossary are specific to the Response Protocol Tool Box but conform to common
usage as much as possible.

Analyte - the name assigned to a substance or feature that describes it in terms of its molecular
composition, taxonomic nomenclature, or other characteristic.

Analytical Approach - a plan describing the specific analyses that are performed on the samples
collected in the event of a water contamination threat. The analytical approach is based on the specific
information available about a contamination threat.

Analytical Confirmation - the process of determining an analyte in a defensible manner.

Analytically Confirmed - in the context of the analytical approach, a contaminant is considered to be
analytically confirmed if it has undergone analytical confirmation, as defined herein.

Basic Screen - utilizes standardized methods based on established analytical techniques for the
analysis of samples collected in response to a contamination threat.

Biosafety Level 1 - suitable for work involving well-characterized biological agents not known to
consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory
personnel and the environment. Work is generally conducted on open bench tops using standard
microbiological practices.

Biosafety Level 2 - suitable for work involving biological agents of moderate potential hazard to
personnel and the environment. Laboratory personnel should have specific training in handling
pathogenic agents and be directed by competent scientists. Access to the laboratory should be limited
when work is being conducted, extreme precautions should be taken with contaminated sharp items,
and certain procedures should be conducted in biological safety cabinets or other physical containment
equipment if there is a risk of creating infectious aerosols or splashes.

Biosafety Level 3 - suitable for work done with indigenous or exotic biological  agents that may cause
serious or potentially lethal disease as a result of exposure by inhalation. Laboratory personnel must
have specific training in handling pathogenic and potentially lethal agents and be supervised by
competent scientists who are experienced in working with these agents.  All procedures involving the
manipulation of infectious materials are conducted within biological safety cabinets or other physical
containment devices, or by personnel wearing appropriate personal protective clothing and equipment.
The laboratory must have special engineering and design features.

Biosafety Level 4 - suitable for work with the most infectious biological agents.  Access to the two
Biosafety Level 4 laboratories in the U.S. is highly restricted.

Chain of Custody - the tracking and documentation of physical control of evidence.

Chemical Weapons - the chemicals that the CWC has placed on its Schedule 1  list.

CLIA Laboratory - a laboratory regulated under the CLIA program.

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Clinical Laboratory Improvement Amendments (CLIA) - regulation that covers all laboratory
testing (except research) performed on humans in the U.S.  Any laboratory participating in the CLIA
program that does diagnostic testing, verification, or proficiency testing is exempt from select agent
regulation, but the laboratory must follow specific procedures.

'Confirmed' - in the context of the threat evaluation process, a water contamination incident is
'confirmed'  if the information collected over the course of the threat evaluation provides definitive
evidence that the water has been contaminated.

Core Field Testing - analysis performed at the investigation site for radiation, cyanide, residual
chlorine, and pH.  Core field testing is performed as part of site characterization and is composed of
two elements, afield safety screen and rapid field testing.

'Credible' - in the context of the threat evaluation process, a water contamination threat is
characterized as 'credible' if information collected during the threat evaluation process corroborates
information  from the threat warning.

Environmental Chemistry Laboratory - any laboratory that is set up to perform analysis of water
samples for compliance with the Safe Drinking Water, Clean Water Acts, or other applicable
environmental regulation, as well as other chemical parameters that are important to system operation
and overall water quality. These laboratories have the instrumentation necessary to implement
methods for chemical analysis of a water sample.

Established Analytical Techniques - these techniques are commonly employed in a large number of
laboratories  and form the basis of many standardized analytical methods.

Expanded Field Testing - analysis of water at the site of a suspected contamination incident for
parameters beyond those covered under core field testing (e.g., VOCs, chemical weapons, biotoxins,

Expanded screen - application of exploratory techniques for chemical contaminants that do not have
standardized methods. Additionally, the expanded screen provides laboratories with additional  options
regarding the instrumentation used to implement both established and exploratory techniques;
however, the results may not be considered definitive and thus may require confirmation.

Exploratory Techniques - techniques capable  of detecting chemicals that are not included in existing
standardized methods. They may employ less common instrumentation than those in the standardized
methods, or  they may simply not yet be specifically used in standardized drinking water methods.

Field Safety Screening - screening performed to detect any environmental hazards (i.e., in the  air and
on surfaces) that might pose a threat to the site characterization team. Monitoring for radioactivity as
the team approaches the site is an example of field safety screening.

Field Sample Concentrate - the term used for the retentate from the ultrafiltration device used for the
sampling/concentration of unknown microbial contaminants.

Filtrate - in ultrafiltration, the water that passes through the filtration membrane.

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Food Emergency Response Network (FERN) - a laboratory network for the analysis of
contaminants in food developed through integration with the existing LRN for pathogen analysis and
established forensic chemistry laboratories that serve as reference laboratories for other FDA

Grab Sample - a sample collected at random from the source.

Hazard Assessment - the process of evaluating available information about the site to identify
potential hazards that might pose a risk to the site characterization team. The hazard assessment
results in assigning one of four levels to risk: low hazard, radiological hazard, high chemical hazard, or
high biological hazard.

Incident Command System - a standardized on-scene emergency management concept specifically
designed to allow its user(s) to adopt an integrated organizational structure equal to the complexity and
demands of single or multiple incidents, without being hindered by jurisdictional boundaries.

Incident Commander - the individual responsible for the management of all incident operations.

Infectious - capable of causing infection. In the context of waterborne pathogens, infection is caused
by exposure to water.

Laboratory Analytical  Screening - application of multiple analytical techniques in a laboratory
setting to screen for a wide range of analytes and to confirm tentative results.  (Laboratory analytical
screening is different and separate from laboratory safety screening., field safety screening, and rapid
field testing.)

Laboratory Compendium - a comprehensive, web-based, searchable database of laboratory
capability for environmental analysis in water, air, soil, sediments, and other media.

Laboratory Guide - a plan prepared by a specific laboratory detailing their approach and capabilities
for the 24/7 processing of emergency water samples.

Laboratory Response Network (LRN) - a network of laboratories developed by the CDC, APHL,
and FBI for the express purpose of dealing with bioterrorism threats, including pathogens and some

Laboratory Safety Screening - screening for various hazards that is conducted when samples are
received at the laboratory, and which is designed to reduce the risks to laboratory personnel that may
handle the samples.

Non-standardized method - a method that does not meet the definition of a standardized method.

Opportunity Contaminant - contaminants that might be readily available in a particular area, even
though they may not be highly toxic or infectious or easily dispersed and stable in treated drinking

Pathogen - an infectious microorganism that is capable of causing disease.

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Personal protective equipment (PPE) - equipment and supplies designed to protect employees from
serious injuries or diseasees resulting from contact with chemical, radiological, biological, or other
hazards. PPE includes face shields, safety glasses, goggles, laboratory coats, gloves, and respirators.

'Possible' - in the context of the threat evaluation process, a water contamination threat is
characterized as 'possible' if the circumstances of the threat warning appear to have provided an
opportunity for contamination.

Presumptive results - results of chemical and/or biological field testing that need to be confirmed by
further laboratory analysis. Typically used in reference to the analysis of pathogens.

Priority Contaminants - list of chemicals, biotoxins, and radionuclides that were ranked highly due
to their availability, properties and potential to harm public health if introduced into the drinking water

Rapid field testing - analyzing the water at the site of contamination using rapid field water testing
technology to tentatively identify any chemicals or pathogens.  Rapid field testing is performed as part
of site characterization.

Reference laboratory - the core,  advanced technology, LRN laboratories that can provide analytical
confirmatory testing of contaminants.

Retentate - in ultrafiltration, the retentate contains the particles that do not pass through the filtration

Select Agent - biological contaminants, including some pathogens and biotoxins, that are regulated by
HHS. Only certain laboratories, registered with the CDC in accordance with the Select Agent Act, are
permitted to confirm the presence  of,  and maintain cultures of, select agents.

Sentinel Laboratory  - an LRN laboratory that reports unusual results that might indicate a possible
outbreak, and refers specimens that may contain select biological agents to Reference laboratories
within the LRN.

Site Characterization - the process of collecting information from an investigation site in order to
support the evaluation of a drinking water contamination threat.  Site characterization activities include
the  site investigation,^/e/J safety screening, rapid field testing of the water, and sample collection.

Standardized Method - a method that has been produced as a standard by a recognized method
development body (EPA, ASTM, AOAC, ISO, etc.) or applicable regulatory authority.  A standardized
method has been subjected to review  and validation and is capable of generating data  of sufficient
quality for its intended use. Standardized methods often contain steps to defensibly confirm the
presence and/or quantity of specific contaminants.

Tentative Identification - the contaminant identity is hypothesized based on available information
from the site characterization report.  Examples of situations in which tentative identification might
occur include:  a specific contaminant named in a threat; tentatively positive results for a specific
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contaminant during field safety screening or rapid field testing; physical evidence at the site pointing to
a specific contaminant; and clinical evidence of the identity of the disease-causing agent.

Threat - an indication that a harmful incident, such as contamination of the drinking water supply,
may have occurred. The threat may be direct, such as a verbal or written threat, or circumstantial,  such
as a security breach or unusual water quality.

Threat Evaluation - part of the threat management process in which all available and relevant
information about the threat is evaluated to determine if the threat is 'possible' or 'credible', or if a
contamination incident has been 'confirmed.' This is an iterative process in which the threat
evaluation is revised as additional information becomes available. The conclusions from the threat
evaluation are considered when making response decisions.

Threat Management - the process of evaluating a contamination threat and making decisions about
appropriate response actions.  The threat management process includes the parallel activities of the
threat evaluation and making response decisions. The threat management process is considered in
three stages: 'possible', 'credible,' and 'confirmatory.' The severity of the threat and the magnitude of
the response decisions escalate as a threat progresses through these  stages.

Ultrafiltration - a filtration process for water that uses membranes to preferentially separate very
small particles that are larger than the membrane's molecular weight cut-off, typically greater than
10,000 daltons.

Water Contamination Incident -  a situation in which a contaminant has been successfully introduced
into the system.  A water contamination incident may or may not be preceded by a water
contamination threat

Water Contamination Threat - a situation in which the introduction of a contaminant into the water
system is threatened, claimed, or suggested by evidence. Compare water contamination threat with
water contamination incident. Note that even a threat against a water system is a crime under the Safe
Drinking Water Act as amended by the Bioterrorism Act.

Water Utility Emergency Response Manager (WTJERM) - the individual(s) within the drinking
water utility management structure  that has the responsibility and authority for managing certain
aspects of the utility's response to an emergency (e.g., a contamination threat) particularly during the
initial stages of the response.  The responsibilities and authority of the WUERM  are defined by utility
management and will likely vary based on the circumstances of a specific utility.
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1   Introduction

1.1   Objectives and Organization of This Module
The primary intended users of this module include laboratory personnel and planners who would
provide analytical support to a water utility in the case of a contamination threat to the water supply.
This module is intended to be a planning tool for laboratories that may need to provide an analytical
response in the case of a contamination threat, not a "how-to" manual for use during the actual
incident.  As part of planning for such an incident, laboratories may want to prepare such a manual
specific to their needs and capabilities. They should also exercise and improve the manual from
lessons learned via conducting drills, which may encourage laboratories to "think outside the box"
in responding to contamination threats.

While this module is not based  expressly on regulatory requirements, it should be recognized that
failure to plan for an emergency contamination incident might lead to tragic public health
consequences. Accordingly, the objectives of this document are to:
   •   Describe special laboratory considerations for handling and processing emergency water
       samples suspected of contamination with a harmful substance.
   •   Present model approaches and procedures for analysis of water samples suspected of
       contamination with a known or unknown substance.  These approaches and procedures are
       developed to take advantage of existing methodologies and infrastructure.
   •   Encourage planners to develop a site-specific analytical approach and laboratory guide that
       conform to the spirit and general principles of the model approaches. Sometimes these
       models may represent the best and/or only way of dealing with the analytical issues
       involved. Frequently, they provide an example of the most comprehensive approach.

Planners and laboratory analysts are encouraged to review this module in its entirety, as well
as the other modules in the Response Protocol Toolbox, to obtain a more comprehensive
understanding of the analytical response approach for water contamination threats. As
suggested in the Overview and  Application to the Response Protocol Toolbox, the modules that
perhaps are most relevant to laboratories are Modules 3 and 4, but depending on the nature of the
laboratory, the other modules also may prove helpful. Because of the varied audience for Module 4,
particularly certain sections in Module 4, an attempt has been made to provide explanations of the
subject matter in the various sections that are directed toward certain audiences.  For instance, the
bulk of the technical material for the analytical approach is found in Sections 6 and 8.  Section 5
describes the framework for the development of an analytical approach, so planners may find
Section 5 more useful, whereas laboratory analysts may find the technical material in Sections 6 and
8 more relevant.  Furthermore, different laboratories may also require different levels of
sophistication in the technical material.

It is hoped that the presentation of the material represents an effective compromise among the needs
and capabilities of the wide audience of utilities and laboratories that wish to develop analytical
capability to support the evaluation of water contamination threats.  This module is organized into
ten sections as described below.

       Section 1:     Introduction: describes the overall organization of the document and
                    discusses the concept of due diligence as applied to laboratories in terms of
                    meeting two main goals: the safety of laboratory personnel and provision of
                    quality analytical data.

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       Section 2:     Description of Laboratory Infrastructure in the U.S.: describes existing
                    laboratory resources that might be involved in the implementation of the
                    analytical approaches presented in this module.

       Section 3:     Considerations for Laboratory Analysis of Emergency Samples: briefly
                    discusses infrastructure, staffing, personnel safety, and sample capacity
                    considerations for laboratory analysis of water samples suspected to be
                    contaminated with an unknown substance.

       Section 4:     Field Screening and Sample Collection: provides an overview of the field
                    screening and sampling procedures presented in Module 3 and describes how
                    these activities are linked to laboratory analysis.

       SectionS:     Analytical Approach for Unidentified Contaminants in Water: presents a
                    framework for developing an analytical approach for emergency water
                    samples in response to a specific contamination threat.

       Section 6:     Analytical Approach for Chemical Contaminants: presents a tiered approach
                    for the analysis of unknown chemical contaminants, including biotoxins and
                    radionuclides, in water samples.

       Section 7:     Examples of the Analytical Approach to Site-Specific Situations for
                    Chemical Contaminants:  presents examples of how several, hypothetical
                    utility laboratories with differing capabilities have  chosen to plan their
                    analytical approach, based on the discussion in  Section 6.  Laboratories that
                    choose to perform analysis of emergency water samples and serve a
                    broader client base, such as Federal, State, and commercial labs, may
                    need to adopt a more comprehensive approach, such that they maintain
                    flexibility to provide analytical support in a variety of situations.

       Section 8:     Analytical Approach for Microbiological Contaminants: presents a tiered
                    approach for the analysis of unknown microbiological agents  in water

       Section 9:     References and Resources: lists the references used in the development of this
                    module as well as additional information resources.

       Section 10:   Appendices: provides additional information and materials that may be of
                    value to the reader.
1.2  Laboratory Goals for Responding to Contamination Threats to Water Systems in
     the Context of the Response Protocol Toolbox
The analytical approach discussed in this module is directed at any laboratory potentially involved in
analysis of emergency water samples.  Water utilities are most familiar with their own systems, and
they are often interested in dealing with incidents of all sorts at the local level (i.e., through the use of
their own personnel and their own laboratories). In fact, it is not practical for HazMat responders and
hazard materials laboratories to become involved in every incident that occurs at the thousands of
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water systems across the country. The responsibility falls on water utilities, who routinely investigate
water quality complaints, whether they originate from intentional contamination or not. Accordingly,
during intentional water contamination events, it should be the general goal of non-utility laboratories
to support the utilities.

For any laboratory to exercise due diligence in responding to contamination threats to water systems, it
must meet two specific, essential goals. The first goal is ensuring the safety of laboratory personnel.
The second goal is the timely generation of comprehensive, quality analytical results to support
difficult decisions that must be made during an emergency situation.

1.2.1   Safety
Specific safety considerations for laboratories wishing to receive and analyze emergency water
samples are discussed in more depth in Section 3.  It is important to realize that details important for
laboratory safety are integrated into the threat evaluation (Module 2) and the site characterization
(Module 3) processes, even though they occur outside of the laboratory setting.  Information in these
other modules impact laboratory safety in several ways. First, the site characterization and threat
evaluation processes help define the hazard conditions at the site of sample collection, which govern
who should collect the  samples and which laboratories should analyze them. For highly hazardous
samples, samples should be collected and analyzed by specifically trained  personnel, namely HazMat
responders and laboratories that specialize in the handling of specific hazardous substances. This
mitigates potential exposure to unprepared laboratory personnel. As  an example, if the site
characterization  results indicate a potential radiological hazard, samples would be delivered only to
laboratories that specialize in the analysis and handling of radiological materials.

Second, in the threat management process, water contamination incidents  range from 'possible' to
'confirmed'.  The principle set forth in Module 2 is that, to date, there are many, perhaps thousands, of
'possible' incidents (ones that are not really intentional contamination incidents) for every 'confirmed'
incident (one in which contamination has occurred).  Those incidents falling into the 'confirmed'
category are those that generate samples containing a harmful contaminant. Even among those
samples, it is expected that the vast majority will not contain highly hazardous materials (e.g.,
chemical or biological warfare agents or radionuclides). Naturally, there is a continuum, described in
Module 2 as  'credible', between the 'possible' and 'confirmed' categories. A contamination threat is
deemed 'credible' if additional information collected during the evaluation supports the likelihood that
contamination has occurred. However, the number of 'credible' cases is expected to be just a few
more than the 'confirmed' ones, which is  still  vastly less than the number of 'possible' ones.

In summary, it is likely that most "emergency" water samples will be sent  on the basis of a 'probable'
contamination threat. Samples sent to a laboratory as a result of a 'probable' contamination threat
should be treated as if they contain a potentially harmful substance. However, the site characterization,
along with the threat evaluation process, should result in most highly hazardous samples being
screened out before they reach the laboratory. From a safety standpoint, it is important for a laboratory
to realize that it will not be expected to determine every potential contaminant  For instance, utility
laboratories typically may expect to receive samples from 'possible' incidents. The  utility laboratories
will need additional laboratory support for 'credible' incidents, and specialty laboratories would be
called into service for 'confirmed' incidents.
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1.2.2  Analytical Goals
Utilities and laboratories familiar with regulatory compliance monitoring are accustomed to thinking
about water analysis in terms of contaminant concentrations that may cause chronic (long-term)
toxicity.  In responding to intentional contamination incidents, an important paradigm shift is that one
goal of the analysis  may be to help rule in or rule out the presence of significantly elevated levels of
certain types/classes of contaminants.  Other goals may exist, and their significant features are
discussed below.

Analytical goals for the three levels of the threat evaluation process
The threat evaluation process is important to a laboratory's analytical goals, because part of providing
timely, accurate results is the proper allocation of analytical resources.  The allocation of laboratory
resources to a threat will be determined by the analytical goals of the laboratory and the incident's
credibility category. Regardless  of category, it is important to remember that even if one contaminant
is identified during the analysis, the presence of additional contaminants should also be investigated.
    •  'Possible' — For the vast majority of cases, because it is unlikely that there will be an actual
       contaminant, it is very important to report accurate results and to not misidentify an
       instrumental response.  These results need to be rapid, but not instantaneous.  Keep in mind that
       many of the  decisions about water system operations will have been made before the analytical
       results are back from the laboratory. While speed and accuracy are necessary analytical goals
       for any scenario, they take on a special meaning during the evaluation of 'possible' incidents.
    •  'Credible' — In the few 'credible' cases, laboratories may receive water samples containing
       potentially harmful contaminants; however, the activities performed during the threat
       evaluation and site characterization processes should reduce the likelihood that samples
       containing high hazard materials (as defined in Module 3, Section 4.1.2) reach the laboratory.
       Thus, laboratories should exercise due diligence to meet the goals of protecting their personnel
       and providing timely, accurate, analytical results. The laboratory investigation should be
       focused on those types  of contaminants discussed in Sections 6 (toxic industrial chemicals,
       biotoxins, and  radionuclides) and Section 8  (some waterborne pathogens, etc.).
    •  'Confirmed'— For the  rare 'confirmed' incidents, the laboratories receiving these materials
       should be ones with specific capabilities for the contaminants (chemical, biological, or
       radiological), which will be suspected or known as a result of the site characterization.
       Environmental laboratories will be capable of many analyses, but are prohibited from handling
       materials such as Schedule 1 chemical warfare  agents.  This Module should not be construed to
       suggest that  laboratories intentionally handle materials for which they are not licensed.

Data Interpretation
Another goal of analysis is to interpret data in an appropriate manner. Often, part of the interpretation
involves understanding baseline concentrations. The importance of knowing baseline levels  of
contaminants at a location cannot be overemphasized. Not only does this affect the site
characterization (Module 3) and threat management process (Module 2) in terms of the proper use of
analytical data,  but it may serve the larger goal of creating greater public acceptance of water from a
distribution system that was once contaminated. Most laboratories currently do not retain this
information because they do not necessarily know the sampling location. However, the laboratory may
be aware of typical background levels through analysis of routine samples.  Laboratories should be
aware of issues regarding background data, particularly if they are asked to render an opinion on the
presence of an unusual contaminant.
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1.3   Role of Laboratories in Response to Contamination Threats
While this Toolbox is aimed primarily at utilities, very few utility labs will be able to independently
implement Module 4 in its entirety. However, they may find the information in Module 4 useful in
understanding their analytical options, planning their analytical approach, and developing their
laboratory guide.

Federal, State, and commercial laboratories will  play a critical support role in the response to
contamination threats - specifically, some of these laboratories will be responsible for implementing
the analytical approaches presented in this module.  These laboratories may already be familiar with
some of the material in Module 4. However, they should work with their utility clients to ensure that
the utilities are familiar with the capabilities of the laboratory. In working with the utility, the
laboratory should be aware that response to a contamination threat is led by the incident commander,
who may be from the water utility.  Please see Module 1, Section 4.4 for more details on the Incident
Command System and the role of the laboratory  within it.

Utilities need to have confidence that laboratories that agree to process emergency water samples
operate according to the following guidelines:
   •  Apply the analytical approach presented in this module according to the circumstances of a
       particular incident and the needs of the client.
   •  Maintain facilities and implement procedures for ensuring the security and integrity of samples
       and analytical results that may be considered as evidence for use in prosecution.
   •  Receive and process emergency samples  24/7. The laboratory should develop an appropriate
       plan for staffing, sample receipt, and internal chain of custody.
   •  Provide results to the client in a time frame stipulated by the client.  The laboratory should be
       prepared to provide the client with an estimate of the time frame in which results may be
       available.  As discussed in Module 2, the utility may need to take certain response measures
       before analytical results are available.  Accordingly, the time frame may be dictated by site-
       specific factors, such as the hydraulic residency time within a segment of a distribution system.
   •  Implement appropriate quality assurance and quality control (QA/QC) procedures, and report
       the QC data along with the analytical results. See Section 3 for additional discussion.
   •  Use proper channels for reporting results.
   •  Provide support in the analysis and interpretation  of analytical results.
   •  Have a back-up plan for processing samples should the laboratory's facility become unusable
       or unavailable.

Laboratories may wish to develop their laboratory guide in accordance with these guidelines, and to
share these plans with their clients. Timely and accurate results from the laboratory may provide
valuable input for making decisions about how to proceed with a response to a contamination threat.
Identification of a harmful contaminant in a water sample would likely trigger additional public health
measures, including additional sampling  to characterize the spread of the contaminant, and possibly
some initial remediation efforts. Likewise, if laboratory results reveal nothing out of the ordinary, the
response would likely be terminated, and any precautionary public health measures could be cancelled
or scaled down.
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2   Description of Laboratory Infrastructure in  U.S.
The analytical approach described in the module was developed under the assumption that it would be
implemented using existing laboratory infrastructure. If an environmental laboratory response
network, designed specifically to analyze environmental samples, is developed in the future, the
approaches presented in this document may be revised to take advantage of the new resource.  Figure
4-1 summarizes laboratory infrastructure, as it currently exists, for the analysis of environmental
samples. Discussion of both access to and roles of these laboratories during the response to an
intentional contamination threat or incident follows.
                 Chemical Analysis
Biological Analysis

                   Chemistry Labs
Lab Response



Microbiology Labs
Figure 4-1.  Summary of Types of Laboratories by Contaminant Class

The following two sections provide a general description of the laboratory infrastructure for the
analysis of chemical and microbiological contaminants in a water matrix.  A comprehensive, web-
based, searchable database of laboratory capability for environmental analysis in water, air, soil,
sediments, and other media will be provided in the Laboratory Compendium when available. It is not
a listing of laboratories approved, certified, or recommended to analyze samples from intentional
contamination incidents. Rather, the Compendium is designed to be a tool for searching for
laboratories and determining their ability to perform various analytical techniques, such as those
presented in this module.

2.1  Chemistry Laboratories
In addition to laboratories within water utilities, standard and specialized chemistry laboratories within
Federal, State, local, city, and municipal government agencies, as well as commercial laboratories,
may support analysis of chemicals in water samples. Some laboratory resources may also be available
from the academic and industrial sectors. For example, a major chemical manufacturer in an area
might want to bring their laboratory operations to bear during the evaluation of an incident in which
their products are suspected in a water contamination threat. Many academic and industrial
laboratories, however, may not necessarily be set up to rapidly respond to water contamination threats
without extensive planning.  Regardless of their origin, it is anticipated that four broad categories of
analytical chemistry laboratories would play a role in implementing the chemistry procedures in the
analytical approach:  environmental chemistry, radiochemistry, biotoxins, and chemical weapons.

2.1.1   Environmental Chemistry Laboratories
This group forms the largest sector of the laboratory infrastructure for analysis of chemicals in water,
and includes many EPA, State, and commercial water analysis laboratories.  Environmental chemistry
laboratories are typically set up to perform analysis of water samples for compliance  with the Safe
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Drinking Water or Clean Water Acts, as well as other chemical parameters that are important to system
operation and overall water quality.  It is important to realize that these laboratories are typically
involved in the analysis of contaminants at concentrations associated with chronic (long-term) toxicity,
not the acutely (short-term) toxic levels potentially associated with an intentional  contamination
incident. While it may seem intuitive that laboratories capable of determining contaminants at low
concentrations should not experience difficulties at high concentrations, this is not necessarily the case
for a number of technical and practical reasons.

These laboratories typically have the instrumentation necessary to implement standardized methods for
chemical analysis in a water matrix.  Because many of these laboratories are involved in regulatory
compliance, the laboratory and staff may already be accredited and certified to implement these
methods. However, unless the laboratory tests for the particular chemical analyte on a routine basis,
the laboratory will not necessarily be able to run the associated method without advanced notice. This
includes maintaining an inventory of standards and reagents, setting up the instrument for a particular
method, and having staff trained to run the method.  This may be particularly relevant in the context of
chemical analysis in the case of a suspected intentional contamination incident since many of the
chemicals of greatest concern are not routinely analyzed for in water, even though standardized
methods are available.

Some environmental chemistry laboratories may have unique capabilities for analysis of select
radionuclides or biotoxins, but this is not the expected norm. Analysis for these chemicals may need to
be performed by a specialty laboratory as discussed below.  Further, there are a number of research
laboratories within the government and academic sectors that may be available on a limited basis.
These laboratories are typically involved in method development, and thus are equipped with advanced
equipment and highly trained analysts that provide capability for implementation of exploratory
techniques that are currently beyond the means of other environmental chemistry laboratories.
2.1.2  Radiochemistry Laboratories
If a radioactive contaminant is suspected, analyses should be performed by a laboratory specifically
equipped to handle such material and analyze for a range of radionuclides.  EPA, DOE, States, and
commercial firms have laboratories dedicated to the analysis of radioactive and/or nuclear material.
For further information about EPA's laboratory services and radiological emergency response
programs, see http://www.epa.gov/radiation/programs.htm - er.

Another source of support in the case of an attack utilizing a radiological contaminant is the Federal
Radiological Management Center (FRMAC) operated by the Federal Emergency Management Agency
(FEMA).  FRMAC is set up to provide rapid response teams and emergency management services
related to incidents involving radioactive materials.  This center works with a number of Federal and
State agencies and draws on a variety of resources including fixed and mobile laboratories. FRMAC
also maintains databases of national laboratory resources and radiological capabilities. Information
regarding FEMA's Radiological Emergency Preparedness Program can be found at
2.1.3  Biotoxin Laboratories
Currently, few laboratories are set up specifically for the analysis of biotoxins. Those in existence
primarily focus on the analysis of marine biotoxins in coastal waters and seafood products.  Some

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Laboratory Response Network (LRN) laboratories (see Section 2.2.1) may have the capability to
analyze for select biotoxins in water samples, assuming proper sample preparation. In addition, there
are a number of laboratories in government and academia that perform biotoxin analysis, usually for
other matrices than water (e.g., seafood or agricultural products).  It is possible that some biotoxin
analyses could be performed in qualified environmental chemistry laboratories using techniques such
as GC/MS, HPLC, immunoassay, and possibly LC/MS; however, such capability may not be currently

2.1.4  Chemical Weapon Laboratories
For the purposes of the Response Protocol Toolbox, a "chemical weapon" refers to those chemicals
that the Chemical Weapons Convention (CWC) has placed on its  Schedule 1
(http://www.cwc.gov/Regulations/cfr-15/part-712-sl_html).  This list includes toxic chemicals with
few or no legitimate other purposes, that were developed or used primarily for military purposes
(http://www.cwc.qov/lndustrv Outreach/Publications/002/cwc-b0001 html). CWC also monitors chemicals
on two other Schedules and certain "unscheduled discrete organic chemicals." A list of chemicals in
the CWC Schedules appears in the appendix in Table 4-18. Some of these other chemicals (not on
Schedule 1) may be present in water through a number of routes other than intentional contamination.
For instance, there are some relatively non-toxic chlorinated hydrocarbons listed on Schedule 2
because they can be precursors to Schedule 1 chemicals. Coincidentally, these chemicals may also be
disinfection byproducts, a term which refers to the hundreds of substances formed in very small
amounts by reactions between drinking water disinfectants and substances naturally present in the

Only a few laboratories are qualified and permitted to work with concentrated Schedule 1 chemical
weapons surety material. In fact, the only two chemical weapons surety laboratories in the U.S. are the
U.S. Army's Edgewood laboratory  and Lawrence Livermore  National Laboratories.  These
laboratories can only be accessed through specific channels (e.g., through certain Federal agencies
such as FBI). A broader group of laboratories can work with dilute chemical weapons materials, such
as might be encountered in a water  contamination incident; however, the ability to access these
laboratories through normal channels is uncertain, and even if such capability can be accessed, analysis
may not be widely available. In contrast, many  environmental laboratories work routinely with
Schedule 2,  Schedule 3,  and unscheduled chemicals, and analytical standards for many of these are
readily available.
2.2   Microbiological Laboratories
The analysis of waterborne pathogens will likely be performed either by an environmental
microbiology laboratory or a laboratory that is part of the Laboratory Response Network (LRN). This
may include hospital laboratories, medical laboratories, public health laboratories, and environmental
microbiology laboratories. However, the missions and capabilities of these two distinct sets of
laboratories are significantly different,  and neither may be particularly well prepared for the analysis of
all biological terrorism (BT) contaminants of concern in a water matrix. The potential role of each of
these types of laboratories in responding to a water contamination threat involving pathogens is
discussed in the following two sections.
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2.2.1  Laboratory Response Network
The Laboratory Response Network (LRN) was developed by the Centers for Disease Control (CDC),
the Association of Public Health Laboratories (APHL), and the FBI for the express purpose of dealing
with bioterrorism (BT) threats, including pathogens and some biotoxins
(http://www.cdc.gov/cic/functions-specs/function4Docs/nLRNvision-summary.doc).  Various
laboratories within each State participate in the LRN (see http://www.bt.cdc.gov/emcontact/index.asp
for contact information).  Laboratories that are part of the LRN can analyze the select agents
(http://www.bt.cdc.gov/Agent/agentlist.asp) subject to legislative requirements set forth in the Select
Agent Regulation (42 CFR 72, http://www.cdc.gov/od/sap).  The legislation requires that, subject to
certain exemptions, entities possessing biological agents that are listed as select agents must register
with CDC and/or USDA's Animal and Plant Inspection Service (for veterinary purposes,
http://www.aphis.usda.gov/) and demonstrate compliance with specific safety and security standards
for handling these agents.

Two details of select agent regulation (http://www.cdc.gov/od/sap/faq.htm) that might be of immediate
interest are: 1) The USA Patriot Act places restrictions on persons who possess select agents and
provides criminal penalties for possession of such agents that cannot be justified for specified peaceful
purposes (http://www.cdc.gov/od/sap/addres.htm). 2) Any diagnostic or Clinical Laboratory
Improvement Amendments (CLIA) laboratory that does diagnostic testing, verification, or proficiency
testing is exempt from the regulation. However, the director of such a laboratory must notify the
Department of Health and Human Services (HHS, see contact info above) immediately upon
identifying specific select agents, and it must transfer the agents to a registered facility or destroy them
(unless directed otherwise by law enforcement or HHS) within 7 calendar days of identification of the
select agent, subject to certain exemptions. Retention of any select agent as a positive control or
reference sample is not permitted in this case.

Thus, by legislation, confirmatory analysis of samples containing select pathogens, such as Bacillus
anthracis, Brucella spp., Yersiniapestis, Francisella tularensis, and C. botulinum toxins, among
others, must be performed through the LRN.  It should be noted that the LRN also performs analysis of
biological samples other than the "select" agents, and many of the waterborne pathogens of concern
are not select agents.  Since the LRN will be involved in an analytical response to any bioterrorism
incident, it is important to understand the structure and organization of this network.  The LRN,
composed of city, county, State, and Federal public health laboratories, is in a perpetual state of
evolution as capabilities are matched with current needs. Figure 4-2 provides a schematic overview of
the current LRN structure.
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                                                                 MODULE 4:  Analytical Guide
Figure 4-2.  Diagrammatic Representation of the Laboratory Response Network
The LRN membership is organized into "Sentinel Labs" which recognize an agent, rule it out, and/or
refer the sample to the next level for confirmatory testing, performed in "Reference Labs". At the top
of the pyramid are "National Labs" (namely CDC and USAMRIID), which are capable of definitive
characterization of even the most hazardous biological agents.

Although the LRN is set up to identify and characterize dangerous pathogens through an upward
referral system, most LRN laboratories are not equipped to process water samples that may contain
these pathogens or their toxic byproducts.  Specifically, they do not have appropriate protocols to
process the relatively large sample volumes needed for analysis of pathogens at low concentrations that
are still of public health concern.  For example, some Reference laboratories have received
standardized environmental protocols for handling dry samples that might contain Bacillus anthracis,
Brucella spp., Yersiniapestis, Francisella tularensis, C. botulinum toxins, and Staphylococcus
enterotoxins; however, protocols are not yet in place for handling water samples containing these

The LRN can accept specimens and samples from hospitals, clinics, the FBI and other law
enforcement groups, emergency medical services, the military, and other agencies.  Thus, it may be
reasonable to expect that water utilities could work through their local or State health departments to
deliver samples to LRN laboratories.  However, this is complicated by regulations governing the
transport of samples that are known or suspected of containing select pathogens.  Specifically, such
samples can be shipped only in an approved and appropriately marked container (see Section  6 in
Module 3 for details, including the use of technical escort services). While these containers are
adequately sized to ship clinical specimens and culture tubes, none are of sufficient size or integrity to
ship the large volumes of water (a minimum of 10 liters) that are necessary to achieve the desired
detection limit.  These issues need to be resolved before LRN laboratories can be engaged in the
response to a BT incident at a water system. The protocols presented in this module are one proposed
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Another challenge arises from the fact that public health and environmental protection are legislated
and managed differently by each state. Only four states have a single state agency that is responsible
for both public and environmental health. All other states have one agency responsible for public
health issues and another for environmental issues.  In addition, some states also separate their state
public health (clinical) laboratories from the state environmental laboratories.  Only 14 state public
health laboratories also serve as the state environmental laboratories (Arkansas, Colorado, Connecticut,
Iowa, Kansas, Louisiana, Maine, New Mexico, North Carolina, South Carolina, South Dakota,
Tennessee, Virginia, and Wisconsin). Personnel at these  14 laboratories, however, rarely handle both
clinical and environmental samples.  Some states even have strict rules that prohibit cross-training of
public health (clinical) microbiologists and environmental microbiologists. To further complicate
interactions and communications among agencies, the individual responsible for drinking water is
located in the health agency in half of the states and in the environmental agency in the other half of
the states.
2.2.2  Environmental Microbiological Laboratories
Environmental microbiological laboratories, including those of EPA, state environmental agencies, and
the commercial sector, typically perform analyses for waterborne pathogens.  Most of these
laboratories have the equipment and staff necessary to perform classical microbiological methods, and
routinely analyze for indicators of fecal contamination such as fecal and total coliforms and E. coli.
Culture techniques are available for many of the more common waterborne pathogens such as Vibrio
choleras, Salmonella enteriditis Typhi, and Shigella spp.; however, analyses for these pathogens are
not routinely performed in most environmental microbiological laboratories.  While some
environmental microbiological laboratories have expanded capabilities to analyze for parasites such as
Cryptosporidium and Giardia or to perform molecular assays for some organisms, these capabilities
are not widespread.

While many environmental microbiological laboratories are well equipped to analyze for
microbiological contaminants in a water matrix, they generally lack the infrastructure, training, and
methods to analyze for many pathogens of concern. Furthermore, as discussed in Section 2.2.1, only
laboratories registered for the analysis of select agents are legally permitted to analyze for those agents,
and currently most registered labs reside in the LRN. Thus, even if environmental microbiological
laboratories develop additional capabilities for pathogen analysis, they could not perform such
analyses without registering for select agents.
2.3  Integration of Laboratory Resources
Sections 2.1 and 2.2 presented a brief overview of the laboratory infrastructure that will likely be
called upon to implement the procedures presented in this module.  While the core infrastructure may
exist for both chemical and microbiological analysis, no mechanism currently exists to provide
coordination in a manner conducive to optimal analytical response. At a minimum, this will create a
greater logistical burden on the organization coordinating sampling and shipment to qualified
laboratories.  In the worst case, these inefficiencies may result in an incomplete analysis of an
unknown, shipment to the wrong laboratory, or delays in receiving time sensitive information.

Formation of environmental laboratory response networks would help to address these coordination
issues.  Such networks are in existence for the analysis of clinical samples (CDC's LRN) and food
samples (FDA's Food Emergency Response Network [FERN]).  The FERN was developed through
integration with the existing LRN for pathogen analysis and establishment of regional forensic

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                                                                 MODULE 4:  Analytical Guide

chemistry laboratories that serve as reference laboratories for other FDA laboratories. In the absence
of a formal network, the analytical response to water contamination threats may be supported by the
laboratory infrastructure as it currently exists.

Accordingly, the approaches described in this module were developed for implementation by the
existing laboratory infrastructure.  Some states have established/will establish network-like entities to
coordinate laboratory efforts. The following steps may help states better integrate laboratory resources
and provide a more coordinated response to water contamination threats:
   •   Establish environmental chemistry laboratories that are capable of implementing both basic and
       expanded screens (see Sections 6.3  and 6.4) for unknown chemicals in water samples.
   •   Establish environmental microbiology laboratories within the LRN that are capable of
       performing Sentinel testing for pathogens of concern in a water matrix.
   •   Determine those biotoxins that will likely be analyzed for in environmental chemistry
       laboratories and those that will be analyzed for in LRN laboratories. Considering the range of
       techniques used to measure biotoxins, there may be some overlap in biotoxin capability.
   •   Establish a  clear sample referral system for the analytical confirmation of tentatively identified
       contaminants, in cases where the environmental chemistry laboratory cannot perform it.  This
       concept is integrated into the LRN for microbiological analysis but is not formally defined for
       chemical analyses.
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3   Considerations for Laboratory Analysis of Emergency Samples

Laboratories participating in the analysis of emergency water samples that may contain an unknown
and potentially dangerous substance have additional responsibilities beyond those associated with
routine analyses.  This section briefly discusses some of the special issues related to safety,
infrastructure, responsiveness, data reporting, quality assurance, and legal admissibility of scientific
evidence that laboratories should consider before engaging in the analysis of emergency samples. This
discussion is not intended to comprehensively address all issues that laboratories may face, but focuses
on issues specifically dealing with the analysis of emergency water samples.  This discussion applies
largely to fixed laboratories, not mobile laboratories. Mobile laboratories often are designed to meet
specific needs, so it is anticipated that most analyses will  be performed by fixed laboratories, which are
likely capable of a wider range of analytical methodologies.

This section primarily deals with operations within the laboratory during the analysis of emergency
water samples. It is also important, however, for the laboratory to keep in mind its role within the
incident command structure, which, as discussed in Module 1,  is through the "laboratory point of
contact." The incident command structure, which must be developed at the local level, establishes and
clarifies the roles of each of the various participants (water utility emergency response manager, first
responders, state drinking water program personnel, laboratory personnel, etc.) and how they should
interact with each other.
3.1   Safety
This section seeks to promote the safety of laboratory personnel during the analysis of samples arising
from the suspected contamination of the water supply, which is subject to regulations with which most
laboratories should be familiar.  In addition, the entire Toolbox, including the analytical approach
presented in Sections 6 and 8 of this module, is intended to enhance the safety of laboratory personnel.
For instance, it is important to realize that during the site characterization process, field safety
screening and rapid field testing have occurred. This may identify potentially hazardous samples
before a decision is made regarding the laboratory that will receive the samples. In fact, part of site
characterization is the site hazard assessment, in which the site is categorized as low hazard,
radiological hazard, high chemical hazard, or high biological hazard.  The results of this site hazard
assessment should dictate the laboratory that will be used for analysis, and they should also help assure
that only laboratories equipped to deal with highly hazardous materials will receive samples potentially
containing such materials.

Considering that the vast majority of evaluated threats that generate laboratory samples will likely not
prove to be intentional contamination incidents (see discussion in Section 1.2 of this module),
additional risks may be manageable. Due to site characterization procedures, environmental chemistry
laboratories may have increased confidence that they will not be processing hazardous biological
agents.  In the unlikely case that such a sample does reach the laboratory, the measures described
below and the analytical approach in Sections 6 and 8 are designed to reduce the risk to laboratory
personnel.  Accordingly, many more laboratories may be willing and able to help respond to potential
intentional contamination incidents.
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3.1.1  Health and Safety Plan (HASP)
Under current regulations, laboratories are required to have a plan in place to ensure worker safety.
Some laboratories may wish to treat certain emergency water samples as hazardous material as defined
in Module 3, whether it be chemical, biological or radiological in nature, and to develop a specific
health and safety plan (HASP) to address this potential risk, although there is currently no requirement
to do so in most cases.  Information on HASPs is available at
http://www.ertresponse.com/health safety/index.htm, along with an electronic expert system jointly
developed by EPA and OSHA (http://www.osha.gov/dts/osta/oshasoft/ehasp/) to help determine the
appropriate controls of health and safety hazards for a specific  situation.

Laboratory personnel involved in the handling and analysis of water samples should have appropriate,
current safety training that will allow them to conform to applicable regulations. Laboratories,
although not required, may wish to explore some of the measures contained in regulations for the
handling of hazardous materials, such as OSHA 1910.120 (http://www.osha.gov). If planners and
laboratories do not conclude that these regulations are applicable to them,  they may still wish to adopt
some of the principles in these regulations. For instance, laboratory personnel may work in
cooperation with a designated "buddy" and maintain visual and/or vocal contact with the buddy at all
times during the analysis.  This system may provide an additional level of protection compared to
regulations applicable for most environmental chemistry laboratories, which do not necessarily rely on
the "buddy" system.
3.1.2  Personal Protective Equipment (PPE)
Analysis of potentially hazardous samples during an emergency situation may require additional
personal protective equipment (PPE) above that normally used in the laboratory.  Such PPE
requirements should be determined during the creation of the site-specific HASP described in Section
3.1.1.  The requirements should be contained in the HASP, and PPE should be freely available to
laboratory personnel.  Personnel should be trained, competent, and medically certified (particularly for
respiratory PPE) to use all necessary levels of PPE, in accordance with applicable regulations (i.e.,
OSHA 1910.120 or OSHA 1910.132 (http://www.osha.gov). along with local or State requirements).

Conventional PPE may be used in conjunction with hand-held "sniffer-type" instruments, which can
monitor for a variety of preselected volatile organic and inorganic compounds.  References such as
http://www.chrismanual.com, http://www.osha.gov/SLTC/personalprotectiveequipment/index.html,
and http://www.cdc.gov/niosh/npptl/default.html, should be consulted for more detail on special PPE.
For instance, butyl gloves and full-face shields should be considered for optimal protection,
particularly during pouring and  splitting of non-volatile samples when maximum risk of accidental
exposure could occur.

Although not necessarily a personal protection issue, care should be used when using PPE to preserve
the forensic integrity of the samples. For example, dirty laboratory coats and gloves could result in
cross-contamination of samples. Hair bonnets, aside from some safety benefit, may prevent loose or
attached hair from contacting samples, which could potentially introduce a variety of contaminants into
the sample.
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3.1.3  Communication to Increase Information Quality about Hazardous Samples
Information about the collection site may be an invaluable component in personnel safety. In general,
laboratories may be asked to analyze samples that originate from two types of sources: 1) those with
rigorous sample collection procedures and 2) those using less-than-perfect sample collection procedures.
In either case, and particularly the latter, it is recommended that the laboratory be fully informed about
the sample collection and site investigation procedures, including any field safety screening and rapid
field testing results, to ensure not only personnel safety but also analytical integrity. The laboratory may
wish to take several steps to become more fully informed. One such step is to inquire if the field
personnel followed the procedures and performed the tests suggested in Module 3 for site
characterization. Another possible step is to establish a system to review procedures used to collect the
samples and assess the reliability of the source of the samples. A third step might be for laboratories to
enhance their communication with the field sampling teams.

With respect to enhancing communications, representatives from the laboratory ideally would be present
during site characterization and sampling to provide as much information as possible to the laboratory
analysts regarding sample collection, field screening, sample transport, and eventual analysis.
Representatives from the laboratory might then accompany samples to the laboratory and interact with
the laboratory personnel while maintaining contact with the field personnel. A less ideal case might be
that the laboratory can readily communicate interactively in real time with the field sampling team so
that they can provide details of sampling strategies, environmental conditions, and other pertinent
information to the laboratory. In any case, the written site characterization report (see Module 3) should
be provided to the laboratory  at the time of sample delivery or faxed separately. Direct verbal
communication, such as a conference call to discuss the site characterization findings, should improve
the quality and clarity of the information in such a report.

It is important to note that different organizations may use different terminology when discussing issues
related to potential contamination events, ranging from a description of the contaminants, to what is
meant by field testing, to descriptions of laboratory results (i.e., is a "negative" result good or bad?).  The
glossary to this module attempts to standardize these terms, but it is imperative that laboratories ensure
that necessary and effective communication is not impeded by inconsistent terminology.

3.1.4  Special Procedures  for Safe Handling of Hazardous Water Contaminants
Examination of incoming packages
Infrastructure requirements for the safe receipt of packages are discussed in the next section.  In
addition, the staff in the receiving area should be trained in the identification of safety hazards
associated with packages. Sometimes these hazards are indicated by warning labels required by DOT
regulations (http://hazmat.dot.gov/) and/or information contained on the shipping papers.  Other
hazards may result from improper packaging and shipment.  They include, but are not limited to:
obvious leaks, breaks in packaging tape or custody seals, damage to packaging, unusual stains on
shipping container, strange odors, etc. (Note: It is not advisable to smell or taste the package).

Laboratory safety screening upon receipt
During the site characterization process, samples from a site are subjected to field safety screening
and/or rapid field testing, as described in Section 4.1 of this module. To reduce risks associated with
potential, undetected hazards, laboratories may wish to screen the sample for various hazards upon
receipt at the laboratory,  regardless of the reported field safety screening results.  Specifically, some of
the safety screening techniques employed in the field (see Module 3) may also be used in the

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laboratory safety screening.  Some of these techniques may, in fact, be performed better in the
controlled conditions of the laboratory.

If the safety screening tests indicate the presence of a previously undetected contaminant, the sample
should be referred to the appropriate laboratory, depending on the type of hazard (radiological,
biological, high hazard chemical, low hazard chemical), as described in Section 4, Module 3. For
instance, a positive test for radiation would prompt referral of the sample to a radionuclide laboratory,
whereas a positive test for cyanide, a low hazard chemical, would allow the sample to remain at the
environmental chemistry laboratory and be treated as a cyanide sample.

Avoiding aerosols
The water solubility of potential contaminants sometimes contributes to their safe handling. Namely,
as long as the contaminant remains in the bulk aqueous solution, the principal risk involves ingestion.
Therefore, steps should be taken to avoid volatilizing or aerosolizing water  samples, which  would
then increase the inhalation risk.  For instance, the pressurized portion of the ultrafiltration device used
for concentrating microbial samples (Section 8) is a closed system which prevents the formation of
aerosols, assuming there are no leaks. Analytical methods should be appropriately selected to reduce
volatilization and the formation of aerosols (e.g., performing extractions in sealed vials). Accordingly,
separately funnel liquid-liquid extraction, which may release aerosols when vented, is not
recommended unless laboratories can utilize appropriate hoods or other precautions.

Some aerosol generation is unavoidable. Samples, particularly biological ones, may produce aerosols
when shaken vigorously for homogenization, and these aerosols should be contained.  Purge-and-trap
technology for analysis of volatile organic compounds produces aerosols, which are contained within
the instrument, provided that the purge vessel is not accidentally broken during analysis. Also,
inductively coupled plasma and some atomic absorption techniques for trace metal analysis must
produce aerosols to function properly. For optimal protection, these instruments have to be properly
vented to minimize inhalation risk. Manufacturers of modern instruments have designed their
instruments to minimize aerosol release (many of these instruments are used in industrial clean  rooms),
but laboratories should ensure that the venting on their instruments is adequate. If this is not possible,
because of the short instrument run times for metal analysis, laboratories may consider performing
these analyses after other procedures have been used to screen for the presence of other  volatilizable or
aerosolizable contaminants.

As a general principle, dilution of a hazardous water sample with laboratory-grade water helps reduce
risks associated with handling of the sample and its analysis for chemical contaminants. Dilution,
however, may have undesirable effects on the ability to detect and quantify the contaminants.
Accordingly, it should be used carefully only as part of an overall handling (and/or analysis) strategy
that balances contaminant effects (e.g., health and safety concerns) with instrument response and
timeliness of the results. Contaminant effects may be important primarily for extremely hazardous
chemicals, such as Schedule 1 chemical warfare agents and biological warfare agents. The need to
dilute may be reduced by safety screening performed both during site characterization (Module 3) and
also upon receipt by the laboratory.

If dilution is desired, "log dilutions" may be attempted. For instance, first, a 1/1,000 dilution may be
analyzed, followed by a 1/100 dilution if nothing is detected in the highest dilution, followed by a 1/10
dilution,  and finally the undiluted  sample. In deciding on a dilution scheme, it  is important to keep in
mind that most drinking water methods  are designed to detect contaminants in the low parts-per-billion

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range.  Concentrations that are hundreds of times this level may be present in samples from the site of
an intentional contamination incident. Appropriate QC measures should be implemented, particularly
with regard to the purity of the dilution water.  Also, before diluting samples in the laboratory, it
should be verified that samples were not diluted in the field prior to shipment to the laboratory.

Although not directly related to safety, dilution may also protect the analytical instrument from
becoming saturated with a contaminant. Procedures for reducing the saturation are usually possible,
but they take time, limiting the availability of the instrument. Working out the correct dilution requires
time, which could be an important consideration.  On the other hand, the presence of sufficient analyte
to saturate the instrumentation may indicate a significant contamination incident. The decision to
implement dilution should accordingly be made during planning.

Reduction of sample volumes used
Like dilution, reducing the volumes of sample  handled may help minimize exposure for both chemical
and biological contaminants.  Some techniques (like those discussed in Section 6) may involve using
smaller volumes of sample.  For example, direct aqueous injection typically uses a few microliters of
sample. Micro-liquid extraction uses about 40 milliliters (mL), and large volume extractions may use
1 liter (L) or more. A sufficient volume of sample is required to achieve the desired detection limits,
but it may be helpful to plan the analytical approach based on the desired goals.  For example, if the
goal is to quantify a high concentration of contaminant (high micrograms per liter), then less sample
may be required than for a low concentration (low to mid-micrograms per liter).

Irradiation and other means  to reduce pathogenic infectivity,  particularly of samples contaminated with
both chemicals and pathogens
Some laboratories may consider irradiating (UV or gamma) the samples prior to chemical analysis to
reduce the risk of possible exposure to pathogens. There may be other ways of achieving the goal of
reducing pathogenic infectivity, such as pasteurization, other heat sterilization, and/or direct filtration.
However, all of these approaches to reduce pathogen infectivity may alter the identity and/or quantity
of some chemicals by thermal, photochemical, or physical means. Also, in the case of filtration,
significant leaching of interfering substances from the filter material can occur.  Therefore, when using
techniques to reduce pathogenic infectivity, it is important to keep in mind the goals of the analysis,
such as analysis of chemicals, detection of viable organisms,  etc.

Currently there is no general consensus on proper use of irradiation and/or other techniques to
reduce risks associated with sample handling and analysis while maintaining the integrity of the
sample and the  analysis. Accordingly, these techniques for  reducing pathogenic infectivity are
not generally recommended (Module 3, Section 4.4.1). The laboratory may wish to explore these
techniques, however, if the authorities in charge of the threat evaluation process (Module 2) believe
there is very good reason to suspect that the sample is contaminated with both biological and chemical
contaminants.  In this case, one way to proceed would be to split the sample prior to irradiation. One
portion could be irradiated and analyzed for chemicals, and a non-irradiated portion could be analyzed
for pathogens, following confirmation that there are no highly hazardous volatile chemicals in the
sample. (Note that an irradiated sample could  be used for the pathogens, provided the analysis did not
require the presence of viable organisms, as is  the case with many molecular assays.) Informed
decisions could then be made about how to safely proceed with other portions of the original, non-
irradiated sample.  Appropriate hoods and other physical control measures should be used when
handling such samples.
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3.2   Laboratory Infrastructure
Infrastructure must be adequate not only to support the analysis of the target analyte in a water matrix,
but also must be sufficient to ensure the safety of laboratory staff and the security of samples and data.
The following subsections describe infrastructure considerations applicable to all laboratories,
followed by those applicable to specific analytical classes.  Details of laboratory infrastructure are
discussed in more detail in this section, particularly as they relate to safety, security, and analytical
quality. This section is not intended to be a laboratory design manual, but rather to highlight areas in
which infrastructure considerations may  play an important role when handling emergency samples.

General considerations for laboratory capability
The infrastructure must be consistent with the goals of emergency analysis. Ample instrumentation
and laboratory equipment should be available to meet analysis goals. This infrastructure should be
compatible with relevant laboratory accreditation requirements, quality assurance plans, and
requirements of auditing groups. This may help ensure that laboratories function well during an
emergency and do not forego sound laboratory practice due to emergency conditions.

Safety equipment
Infrastructure includes any safety equipment such as eyewashes, safety showers, spill containment
devices/supplies, etc.  It also includes first aid kits, which should include inexpensive antidote kits for
various poisons, such as cyanide and organophosphate compounds.  Personnel should be trained on the
availability, indications, and use of these antidotes. Safety  supplies and training materials are readily
available from numerous companies servicing industrial safety needs.

Chemical/biological hoods and physical  control measures
Appropriate chemical hoods, biosafety cabinets, containment glove boxes, and/or other physical
control measures should be incorporated into laboratory infrastructure and may be required by the
HASP. Exhaust and pollution control  systems must be evaluated to determine proper operation prior
to every analysis (i.e., through the use  of appropriate monitors for hood face velocity, etc). The
chemical hood, biosafety cabinet, and/or containment glove box should be cleared of all other
equipment, samples,  reagents, supplies, etc., except those required to open and process the sample
itself.  Some laboratories may wish to  deactivate any contaminants that exist on the outside of the
sample container or the sample opening equipment. In this case, the deactivating solution (10%
bleach, chemical neutralizers, etc) may be kept in the hood or glove box.  Note that deactivating
solutions, including bleach, have finite shelf-lives and must be refreshed accordingly.

Ventilation and physical control requirements for chemical samples vary with hazard classification.
Most laboratories should currently have sufficient controls  for low hazard samples. In general,
occupational exposure to hazardous chemicals in laboratories is described in OSHA standard
1910.1450 (http://www.osha.gov).  This  standard also forms the basis for laboratory safety guidelines
for laboratories possessing one milliliter or less of a pure Schedule 1 chemical warfare agent
(http://www.usapa.army.mil/pdffiles/p385_61.pdf). This link is provided for reference, and should not
imply that a laboratory with a liter of water that contains only 10 microliters of pure agent and that has
the appropriate physical controls should  consider itself an approved laboratory capable of analyzing
these substances.

For biological samples, appropriate equipment is required based on the desired biosafety level (BSL).
For BSL-2, biosafety hoods may be required, while BSL-3  requires a specially designed facility.  See
http://www.cdc.gov/od/ohs/pdffiles/4th BMBL.pdf for design considerations for biosafety hoods and
for more information on BSL requirements for particular biological agents in various forms, e.g. dried

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or in solution.  For example, although B. anthracis is considered an organism that may be safely
contained using Biosafety Level 2 (BSL-2,
http://www.bt.cdc.gov/documents/PPTResponse/table3abiosafety.pdf) conditions, if the procedure is
likely to generate aerosols, it should be handled using BSL-3 conditions.

Sample receipt handling, and security
Adequate infrastructure is required to achieve the goals of safety for laboratory personnel charged with
the receipt, handling, and analysis of potentially hazardous forensic samples. In some cases, the same
infrastructure used for receipt of routine samples may be sufficient, but depending on the existing
facilities, some upgrades may be necessary to safely handle hazardous samples.

Infrastructure-related safety issues begin with initial sample receipt.  The sample receipt area should be
isolated from the analysis area and include features that allow effective handling and security of
samples.  Furthermore, samples should be handled and secured in a manner that will support the
admissibility of the results into a court of law. This may include electronic sample tracking and
impenetrable storage areas.

Samples should be opened in a manner to  maximize personnel safety and minimize laboratory
contamination.  For example,  samples may be opened in a dedicated glove box or hood which is
physically and geographically separate from the hoods used in the analytical laboratory. Laboratories
may wish to take pictures of samples and/or install automatic video surveillance equipment in order to
document sample receipt, handling, and security.  Likewise, laboratories may wish to conduct physical
measurements (e.g., determine the mass and/or volume of the  water sample, upon receipt and at
various stages of analysis).  This may be important for safety as well as forensic reasons.

Dual-use facilities for routine and emergency samples
For routine analysis, laboratories often can anticipate the concentration range of certain chemicals in
water samples and  plan accordingly. However, in the case of an unknown, there may not be  any
information regarding the potential concentration of a particular chemical, and some samples could
contain very high concentrations.  This can lead to significant problems, such as a laboratory becoming
contaminated when unusually high concentrations of a contaminant are present.  To minimize the
potential  for laboratory contamination when working with unknown samples, precautions should be
taken, such as working in a dedicated sample prep area, carrying samples in buckets with gas-tight,
friction-fit lids containing absorbent material in the bottom, and other measures to physically prevent
the accidental introduction of contaminants (including vapors) from water samples into the laboratory.

Aside from safety issues, accurate analytical determinations are related to good laboratory practices,
particularly in the area of cross-contamination of samples. (Note that radioactive contamination may
be preventable by identifying the presence of radioactivity during initial sample screening  procedures.)
In addition to degrading the validity of analytical results, cross-contamination can affect aspects of the
quality assurance features of a method.  For example, contamination of the reagent blank can occur.
The reagent blank is an aliquot of reagent  water or other blank matrix that is treated exactly as a
sample. The reagent blank is used to determine if method analytes or other interferences are present in
the laboratory environment, the reagents, or the apparatus. If  a chemical from an unknown sample
contaminates the reagent blank, the accuracy of all subsequent measurements to identify and quantify
that chemical in a sample may be compromised. In principle,  concerns related to the reagent blank and
other related quality assurance issues are procedurally dealt with by the quality control section of the
chemical or biological analysis method. However, it is still possible for difficulties to arise, especially

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with volatile material that may easily pass through the air from one sample to another or to the reagent

In the case of microbiological contaminants, the high sensitivity of molecular techniques makes them
susceptible to contamination by trace amounts of biological materials. For example, molecular
methods utilizing the polymerase chain reaction (PCR) are extremely sensitive to the presence of any
target DNA. It is imperative that PCR product analysis be carried out in an area physically separated,
with separate airflow, from the areas where the samples are prepared for analysis.  To avoid
contaminating reagents, it is desirable to have a separate reagent preparation facility.  These
considerations warrant  a specialized laboratory facility, specifically designed to deal with the demands
of molecular methods.  Frequently, a core facility strategy is used to minimize the impact of this space
requirement.  In this case, there should be separate preparation areas for suspected biological
contaminants, to prevent possible cross contamination with routine environmental samples, and to
minimize the opportunity for contamination of a laboratory with biological contaminants.

Sample capacity and turn-around time
Laboratory infrastructure involves elements that are desirable for ensuring sufficient analytical
capacity and rapid turn-around time in the case of an emergency incident, while maintaining quality
standards. This includes elements of laboratory staffing, planning of work schedules,  and  creating
provisions for the availability of staff during an emergency.  In addition, the facility should allow for
24/7 access and control of safety measures. For instance, laboratory personnel should be able to
override systems that reduce automatic hood ventilation at preset times to save energy. Laboratories
may choose to perform frequent exercises to meet the combined goals of analysis speed and accuracy.

Sample disposal
Laboratories should have waste disposal plans in place, subject to applicable regulations. As discussed
previously, most samples will likely contain no or little contamination, and hence existing laboratory
waste disposal practices should suffice. In the relatively rare instance that the sample does contain a
hazard, then it is likely  that law enforcement will want the sample retained as evidence and provide
guidance as to its storage and ultimate  disposition when no longer needed. In any case, all regulations
governing the disposal  of hazardous substances should be adhered to when disposing of samples.
3.3   Data Analysis and Reporting
The responsibility of the laboratory during an emergency does not end with sample analysis. At a
minimum, the laboratory should report the results in a timely manner to the designated recipients.
Furthermore, the laboratory may be called upon to assist in analysis and interpretation of the data.
While specific arrangements for the reporting and evaluation of analytical results need to be made
between the laboratory and the client, the following general guidelines will apply in most situations:

   1.  The laboratory and the client (e.g., the water utility emergency response manager or the
       designated incident commander) should agree on the format and content of the report as part of
       their planning. In this manner, incident command will know what to expect and can practice
       interpreting the report.  There are efforts in the forensic community to provide standardized
       guidance on report writing (i.e., the minimum types of information that should be contained in
       such a report).  When it is available, this guidance may be included in this module.

       An important issue in the content of the report arises when the laboratory is asked to provide an
       analysis of a water sample for which the contaminant is unknown (e.g., applying a laboratory

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   analytical screening procedure to a water sample, as described in Section 6.3). Environmental
   laboratories are often familiar with determining specific analytes and providing reports
   regarding those analytes. For example, the laboratory may apply a standardized method and
   report on the analytes listed in the method. However, if the laboratory observes non-method
   analytes during the analysis, several questions arise about how theses  should be reported, such
         •     What is a significant result in terms of the concentration of the non-target analytes?
         •     Should all non-detects be reported?
         •     How much detail is appropriate in identifying and/or quantifying the analytes?

   In principle, the report should be thorough enough so that one does not miss anything
   important, but if too much information is reported, the laboratory may confuse the client.
   These are complex issues that are likely to be situation-specific and may also  be dependent on
   local policy.  Also, reporting  priorities may change during the course of the evaluation of a
   water contamination threat/incident. For example, during the initial phases of the evaluation,
   the water utility emergency response manager may set a high priority  on identifying any
   unexpected substances in the  water, but only above certain concentrations (e.g., normal
   background levels). Later on, as critical decisions may need to be made, management may be
   more concerned about analytical confirmation of identification  and accurate quantification.
   Planning and table-top exercises may help the water utility and laboratory decide on what
   report content is best for them, particularly at various stages of the evaluation.

2.  During a suspected contamination incident, it is important that all relevant information be
   managed through the incident command.  This is especially true for analytical results that could
   be subject to misinterpretation if not placed into the context of the situation.  Thus, analytical
   results should be reported only to those individuals designated by incident command, and
   it will be their responsibility to inform other stakeholders.  The water utility emergency
   response manager (or the designated incident commander) and  laboratory contact should be
   aware of the various applicable Federal, State and local legal requirements, especially for
   reporting infectious diseases.  If they are not, the laboratory should inform incident command
   of these requirements when reporting the results to incident command, provided such reporting
   is permitted by regulatory requirements.

3.  In a crisis situation, the laboratory may be asked to provide tentative results (sometimes called
   a "rolling report") prior to complete review and confirmation, especially in cases where more
   than a couple of hours is required for confirmation. The laboratory may need to provide
   appropriate caveats regarding the validity of the data at this stage of the  analysis.
   Depending on the analytical methods used, such caveats, perhaps in the form  of a clearly
   presented narrative summary, might include: methods and techniques  used, the probability of
   false negative/false positive results, limit of detection, method accuracy/precision, quantitative
   versus qualitative results, and the time necessary to confirm tentative results.  It is the
   responsibility of incident command to weigh all of this information  and make decisions about
   appropriate response actions.

4.  The laboratory should be available to assist in the analysis and interpretation of the results. Not
   only will the laboratory  staff  have a unique perspective regarding the reliability of the method
   and interpretation of results, but they also may have substantial experience with the application
   of the methodology to other samples.  Thus, the analyst may have the  ability to discriminate

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       between results that fall within the normal range of occurrence and those likely to be indicative
       of an actual contamination incident.  As an example, chloropicrin and cyanogen chloride are
       potentially hazardous chemicals at high concentrations in water. However, these same
       compounds can occur at very low levels in disinfected drinking water as disinfection by-
       products, resulting from the reaction of the disinfectant with materials naturally present in the
       water.  An analyst with experience determining these compounds would likely recognize
       elevated levels outside of the range typically encountered in treated drinking waters. The issue
       of baseline (background) levels is critical to the interpretation of analytical results and
       thus to the threat evaluation (Module 2). A more difficult interpretation of the results would
       occur if low levels of such "naturally occurring yet potentially hazardous contaminants" are
       detected, since these levels could represent typical background or the tail of a transient
       contaminant slug, in which case additional sampling and analysis may be necessary.

3.4   Quality Assurance and Quality Control
Standardized methods available in fixed laboratories are designed and verified to provide accurate and
defensible results.  However, methods for analysis are only as good as the people who perform them,
assuming suitable analytical technology is at their disposal. It is common experience that some
individuals obtain better results from analytical methods compared to others due to the skill level of the
analyst, and this may be  particularly true during the analysis of an unidentified contaminant using non-
standardized methods, as discussed in Section 6.  To address these types of concerns, EPA has
developed extensive guidelines regarding the quality of data generated internally and for non-EPA
organizations.  For more details, see http://www.epa.gov/quality 1/exmural.html#genreqts.

There are currently specific QA plans/guidance being developed for forensic analysis of unknowns for
both biological and chemical samples. This QA guidance may be included in a future version of this
module.  Many laboratories may already have quality assurance plans that meet these requirements.
Until (and after) this QA guidance is formalized, laboratories should be aware of legal issues involving
admissibility of scientific evidence, as discussed in the following section.

One consideration with respect to QA/QC for analytical methods used during the evaluation of
suspected water contamination incidents is the objective of the analysis. For instance, one goal may be
to qualitatively confirm the presence of a particular contaminant. Another goal would be to
quantitatively determine the concentration of a contaminant.  Selecting the objectives of a particular
analysis is part of planning for a site-specific response to a contamination threat. In many cases, the
threat evaluation process discussed in Module 2 will drive the purpose of the analysis toward
quantifying chemicals at concentrations from milligrams per liter to low micrograms per liter of
chemicals,  and pathogens at their infective doses.  The analytical approach presented in Sections 6 and
8 reflects this goal. However, depending on the specific plan, other goals may be  applicable.

3.5  Admissibility of Scientific Evidence
If criminal  or terrorist activity is the suspected cause of a contamination incident, any samples
collected and analyses performed may be considered evidence by law enforcement agencies. Many
environmental chemistry laboratories are currently performing water analyses to support regulatory
compliance, and they are familiar with the need to treat samples with precautions necessary for legal
defensibility.  Analysis for regulatory compliance purposes, however, may operate somewhat
differently than analysis  of emergency samples in response to a contamination threat, which has the
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dual role of both providing an emergency response to protect public health and also supporting a
criminal investigation.

The objective of the emergency response is to provide the water utility emergency response manager
(or the designated incident commander) with timely and accurate scientific results (Module 1).
Supporting a criminal investigation may involve additional time and effort.  Improper decisions made
during emergency response may also result in public outcry and/or legal action, whether criminal or
civil, so the quality of data required for a response action may rival that of the criminal investigation.

Meeting these dual goals requires careful planning and analysis of the public health needs and legal
requirements in place for a specific location.  Nevertheless, utility planners should be aware that most
of the groundwork is already in place at laboratories, and may be readily built upon through
appropriate selection of the analytical approach, as well as training exercises.  Some of this
groundwork is described below.

To maintain the credibility of evidence throughout the sampling and analysis process, the laboratory
must demonstrate an unbroken chain of custody and ensure that basic principles of admissibility of
scientific evidence are met. Chain of custody begins with sample collection and shipment to the
laboratory. Sample custody typically becomes the responsibility of the laboratory upon sample receipt.
Documentation should clearly track the sample and analytical results from the point of sample receipt
through reporting of results. Furthermore, when designated laboratory staff are not in possession of
the sample or related information, it should be secured. If there are gaps in the chain of custody or
periods during which the sample or results could have been compromised, the analytical results could
be dismissed by the court.  In cases in which the analysis leads to prosecution of a perpetrator, chain of
custody should continue until law enforcement has determined that any remaining sample is not
needed as evidence.

Certain principles govern the admissibility of scientific evidence in a court of law, and laboratories
processing samples considered as evidence should adhere to these principles to improve the legal
defensibility of their results. There are no universally accepted criteria for the admissibility of
scientific evidence, although State and Federal courts typically use one of three standards: Federal (or
State) Rules of Evidence, the Frye standard, or the Daubert standard. A more detailed discussion of
the admissibility of scientific evidence can be found in the Reference Manual on Scientific Evidence,
2nd ed., which can be downloaded from the Federal Justice Center's web site at
http://www.fj c.gov/public/pdf.nsf/lookup/scimanOO.pdf/$file/scimanOO.pdf.

Note that in the case of scientific evidence, states may develop their own criteria, other than Frye or
Daubert, which are more stringent than the relevancy issue considered in the rule of evidence.
In considering the principles that govern the admissibility of scientific evidence in the context of the
analysis of water samples for known or unknown contaminants, it is most useful to consider the most
stringent standard - Daubert. It is clear that a laboratory would play a crucial role in the selection and
implementation of an analytical approach that would result in data that would pass the Daubert tests.
There are currently efforts underway in the forensic community to prepare guidance for proper
implementation, particularly as it refers to the validity of the analytical results. While this guidance is
not available at this time, it may be included in future versions of this module.  In the meantime, a few
example areas that should  be addressed that would aid in meeting the Daubert standard include:
    •  Quantification of Type  I (false positive) and Type II (false negative) error rates through
       appropriate quality assurance and quality control (QA/QC).

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Use of standardized methods, or methods that have been subject to rigorous peer review if
standardized methods are unavailable.
Participation in a certification or accreditation program for the relevant methodologies.
Participation in interlaboratory studies (or third-party performance evaluation studies).
Supporting documentation for methods, SOPs, QA plans, etc.
Training and competency testing for analysts.
Special training for scientists and analysts required to give expert testimony.
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4   Site Characterization and Sampling
While this module focuses on the analytical approach, laboratory personnel need to have a basic
understanding of the processes implemented prior to transfer of sample custody to the analytical
laboratory.  This understanding may be of value to the laboratory for the purpose of developing
procedures for sample receipt that will ensure the safety of laboratory personnel,  a meaningful
analytical approach, the timeliness and quality of the analysis, and the legal defensibility of the results.

The processes leading up to sample analysis,  namely site characterization and sampling, are covered in
detail in Module 3, "Site Characterization and Sampling Guide," but it is worthwhile to briefly discuss
a few points here. Readers are encouraged to refer to Module 3 for more complete explanations and
extensive description of site characterization  activities, including a general discussion of who will
perform the activities under various hazard conditions. Figure 4-3 illustrates the  steps leading up to
sample  shipment.  The glossary provides definitions of terms used.
                                     Customize the Site
                                    Characterization Plan
                                                              Initial evaluation
                                                           Identify investigation site
                                                           Characterize site hazards
                                                         Form site characterization team
Approaching the Site
                     Conduct field safety screening
                      Observe site conditions and
                       determine signs of hazard
                                    Characterize the Site
                                                          Repeat field safety screening
                      Investigate site and evaluate
                                                          Conduct field water testing
                                      Collect Samples
                                      Exiting the Site
                                     Ship samples to lab
Figure 4-3: Site Characterization and Sampling Process
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4.1   Site Characterization
The left side of Figure 4-3 shows the threat evaluation process conducted in parallel with the site
characterization and sampling procedures.  Throughout the entire evaluation of the incident, the
credibility of the threat is continually reevaluated as new information becomes available. If at any
point the threat is determined to be not credible, the process is discontinued. Thus, samples might only
be sent to the laboratory if the threat is still deemed credible following sample collection, as indicated
in Figure 4-3. The threat evaluation protocol is discussed in more detail in Module 2.

The site characterization process begins with an evaluation of the site hazards. Based on the available
data and initial threat evaluation, a determination will be made regarding the need to implement special
hazardous material handling techniques.  This may dictate the organization or team that is sent to the
site to perform field screening and sampling. While it may be necessary to consider the details of a
specific threat/incident when determining the level of protection required  for the response team,
planning for a response to various scenarios should occur well in advance of an actual threat.
Specifically, response plans should document who would be called to respond to contamination threats
under different hazard conditions.

Upon site entry, field safety screening protocols may be implemented.  The purpose of field safety
screening is to detect any immediate threats to the response team from contaminants in  the atmosphere
or on surfaces. Core safety screening focuses on threats from radiation, but the safety screening may
be expanded to include volatile chemicals,  chemical weapons, and biological weapons as appropriate
for the situation. If any of these threats are detected,  it would likely be necessary to immediately
evacuate the site and send in teams properly equipped to deal with the  hazard tentatively identified
during the safety screening.  The site characterization team should have training in the uses of safety
screening equipment (see section 4.2.2 of Module 3)  and be familiar with  its capabilities and

After the field safety screen has been completed, the  appropriate team  may continue the site
characterization, including rapid field testing of the water. Recommended core field testing consists of
radiation monitoring (in the water), cyanide, chlorine residual, and pH. Section 4.3.2 of Module 3
discusses options for expanded field testing. Note that these core tests are based on historically reliable
or verified technology  Few of these technologies for rapid field water  testing beyond the core
tests, however, have undergone a thorough and independent performance evaluation. Without
reliable performance data, any field testing technology for chemicals, pathogens and/or
radionuclides should be used with caution. The same is true for technology for safety screening,
particularly for biological contaminants. This document is somewhat forward looking, and it
assumes that some of the existing kits will provide some useful data; however, these kits have not yet
been verified.  Verification of several of these technologies is being carried out through EPA's
Environmental Technology Verification program in 2003, and the verification reports can be found,
when available, at http://www.epa.gov/etv/.

There are three objectives of field testing the water: 1) provide additional  information to assess the
credibility of the incident; 2) provide tentative identification of contaminants that would need to be
analytically confirmed m the laboratory; and 3) determine if hazards tentatively identified in the water
require special precautions during sampling. Note that these goals are distinct from the analytical
testing that occurs at the laboratory, even if the same technology is employed at the laboratory as part
of their safety screen upon sample receipt (Section 3.1.4).
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4.2   Sampling
After field testing is completed, samples may be collected using those precautions appropriate for the
hazards identified. A sampling kit that contains bottles and supplies for the proper collection and
identification of each sample should be available.  In Section 4.2.2 of Module 3, Table 3-1 describes
such a sampling kit. Note also that Table 3-1 does not contain any personal protective equipment,
except that required to add the chemicals used to preserve the samples. If any personal protective
equipment is required, it should be included as part of the health and safety plan (HASP) included in
the sample kit (Table 3-1).

In general, samples for chemical analyses may be  collected in clean glass or plastic containers
according to sampling procedures appropriate for the analysis.  The specific sample containers
suggested for chemical analytes are listed in Table 3-2 of Module 3, and correspond to the particular
analysis in the analytical approach set forth in Sections 6 and 8 of this module. The table lists the
number, type, and volume of each sample container, as well as any preservatives or dechlorinating
agents appropriate for the sample.  Laboratories may find the information in these tables useful to
increase their familiarity with incoming samples.

4.3   Sample  Transport and/or Storage
The process flow chart in Figure 4-3 indicates that samples would typically be collected after field
testing regardless of threat credibility; however, a decision must be made whether or not to send
samples to the laboratory immediately following sample collection. This decision should largely be
based on the outcome of the threat evaluation. If the threat is deemed credible, the samples may be
sent to the appropriate laboratory for immediate analysis.  Packaging and transport of the  sample to the
laboratory is discussed in Section 6 of Module 3.  If the threat is not deemed credible, the process is
halted; however, some analysis may still be performed on the samples at the discretion of the utility or
other parties involved in the response.

If samples are not sent to the laboratory for analysis, they should be held in cold storage (protected
from freezing at 4° C) under safe and secure conditions for at least one week following collections, and
possibly longer if dictated by other parties that could be involved in the response (FBI, CDC, EPA,
etc.).  If the samples are stored, then the samples must be securely stored and appropriately preserved
(Section 4.2). Proper chain-of-custody procedures should be maintained, and holding times must be
within acceptable bounds to meet the analytical goals for the contaminant of interest.

4.4   Site Characterization Report and Chain of Custody
Chain of custody is initiated at the time of sampling, along with other sampling documentation. If
samples are sent to the laboratory, all relevant documentation should be submitted at the same time
   •   Contact information for the  sampling organization.
   •   Sample documentation, including chain-of-custody forms.
   •   Details about any pretreatment performed on the samples in the field, such as dilution,
       preservation, dechlorination, etc., if not already included elsewhere.
   •   Site characterization report, including site investigation forms, field safety screening results,
       and results from rapid field testing conducted on the water.
   •   The current stage of the threat evaluation.  Note: the laboratory should be cautioned against
       reducing handling precautions for lower threat evaluation  stages without good reason.

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    •   Instructions on data reporting (i.e., to whom, what format, special reporting requirements, etc.).

This information may be of tremendous value in the development of an analytical approach for a water
sample that may be contaminated with a harmful substance, as discussed in greater detail in Section 5.
The laboratory should be aware that the site characterization report may be incomplete and/or
inaccurate. If the laboratory has any questions, communication (see section 4.5 below) becomes
extremely important. The laboratory may also wish to verify the preservation and/or dechlorination of
some arriving samples (e.g., through the use of test strips for free chlorine and pH). Deviations from
the preservation and/or dechlorination  described on the sample documentation should be noted by the
laboratory, and the laboratory should adjust their sample processing accordingly.

In addition, chain-of-custody procedures should be followed carefully to support future criminal and/or
civil legal action regarding the incident.  Chain-of-custody should not stop with sample receipt but
should also include an internal chain-of-custody procedure. Internal chain-of-custody should be
established for all samples regardless of any questions about chain-of-custody maintained prior to
receipt by the laboratory.

4.5 Communication
Multiple laboratories may be involved, depending on the  nature of the analytes. All relevant
laboratories should be included in the communication process.  Communication between the
laboratory(ies) and sampling team should begin no later than the time of sample collection, especially
in the case of a highly credible threat.  In some cases,  a laboratory may choose to send personnel to the
site to ensure that proper sampling techniques are followed, assist in the interpretation of field test
results, and facilitate chain of custody. This interaction may help laboratories identify any potential
hazards associated with the samples and consider site-specific information in developing an analytical
approach for the specific incident. If laboratory staff cannot be present during sample collection, a
conference call might be scheduled to discuss the information outlined above, as it relates to laboratory
safety and development of an analytical approach, which is discussed in more detail in the following

Communication should be appropriately documented for future reference. Written notes may be taken,
and electronic recording devices may be used, but only to the extent allowed by privacy laws,
particularly for telephone conversations.
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5   General Considerations for an Analytical Approach for Unidentified
    Contaminants in Water

In the case of a water contamination threat, it will likely be necessary to make rapid decisions, based
on limited information, about the contaminants that will be evaluated by the laboratory.  These
decisions may impact the samples that are collected, selection of the laboratory, and the specific
analyses that would ultimately be performed (defined as the analytical approach). In some cases,
evidence from the site or results from field screening may provide some indication about the identity of
the contaminant, and the analytical approach can be adjusted accordingly. However, it is generally
assumed that the presence and identity of a contaminant in the water sample would need to be
analytically confirmed with limited evidence to guide the analysis.  Furthermore, even if a tentative
identification of the contaminant has been made in the field, circumstances may warrant analysis for
other contaminants in addition to those tentatively identified.

A number of officials from various organizations, including the laboratory, may need to be involved in
the development of an analytical approach in response to a specific contamination threat. During
the response to a contamination threat, the laboratory would need to establish clear lines of
communication with incident command, the affected utility, sampling teams, and any other
stakeholders that are not coordinated directly through incident command.  This collective group of
decision officials would need to evaluate available information and work together to develop an
analytical  approach that is appropriate for the circumstances of the specific threat.

The analytical approach may need to be  developed rapidly - in a time frame of minutes to hours.
Planning, preparation, and communication are key to making such decisions in a rapid and
effective manner.  After careful planning, laboratories may wish to formalize their analytical and
management approach in a laboratory guide that is analogous to the response guide (Module 1)
prepared by utilities that summarizes the actions the utilities plan to take during an emergency.

This section lays out a framework for developing an analytical  approach in response to a specific
contamination threat. The technical aspects of the analytical approach for chemicals and pathogens are
described in Sections 6 and 8, respectively.  Hypothetical examples of specific approaches developed
to meet site-specific objectives are given in Section 7. While this framework may be used in real-time
during a response, it should also be used for preparation and planning for such a response.
Laboratories and their customers (utilities, States, Federal agencies, etc.) should work though this
process under various test scenarios to become familiar with the process, and to understand the
capabilities and limitations of a laboratory in implementing the approaches described in Sections 6 and
8.  Laboratories may find they need to expand their capability in a particular area to provide adequate
coverage for target analytes, or it may become apparent that limitations may require use  of other
laboratories for some specialty analyses.

This section is intended not necessarily for laboratories, which may be more interested in Sections 6
and 8, but for planners and managers, who may be more interested in the concepts involved.  Section 5
is divided  into three subsections. The first subsection presents  a decision tool that may serve as a
model for  the development of an analytical approach to a specific contamination threat, based on
different levels of tentative identification. The next subsection, "Initial Assessment of Available
Information" describes potentially useful information from a specific contamination threat to support
the development of an analytical approach.  The final subsection describes the general approach used
for the analysis of unknown contaminants.

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5.1   Framework lor Development of an Analytical Approach
Once the decision to send samples to a laboratory for analysis has been made (see Section 4), it will be
necessary to develop an analytical approach that is appropriate for a specific contamination threat or
incident. Figure 4-4 presents a decision tool that is intended to aid in the development of the analytical
approach. Figure 4-4 is geared towards the analysis of water samples potentially containing an
unknown chemical or biological contaminant that was collected from a site characterized as having
low hazard conditions.  It is assumed that radiation screening has been performed prior to the start of
Figure 4-4.  In particular, if the field testing results for radiation were positive, one would go down an
entirely different, and fairly well-defined, analytical path (see Section 6.4.8).
                            Review the Site
                         Characterization Report
                           Contaminant class
                           nown or suspected?
  Perform Screening for
Chemicals and Biologicals
                          Specific contaminant
                          tentatively identified?
  Perform Screening for
 Chemicals or Biologicals
                          Perform Confirmatory
                             Presence of
   Is additional
                Analytical Approach
                           Analysis Complete. \
                            Report Results. J
Figure 4-4. Decision Process for the Development of an Analytical Approach for Potentially
Contaminated Water Samples

It is important to emphasize that the decision process depicted in Figure 4-4 should be used as a
planning tool, not just during an incident. Laboratories, in conjunction with their clients, should work
through this process prior to an emergency situation to develop and refine their own analytical plans
and procedures. The decision process begins with an evaluation of available information about the
contamination threat that might be of value in developing an analytical approach. The information
used to support this initial  assessment is described further in Section 5.2 and in greater detail in
Module 2.
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The first decision point in the process is an assessment of whether or not there is sufficient information
to make a tentative identification of the contaminant as chemical and/or biological.  If this is possible,
then an entire class of contaminants is eliminated from consideration, allowing focus on the tentatively
identified contaminant class.  If the information is not sufficient to make a determination between
chemical and biological contaminants, then the sample may be treated as a complete unknown. The
recommended analytical approach for a complete unknown is described in Section 5.3.

The second decision point involves tentative identification of the specific contaminant.  At this point,
the contaminant identity is hypothesized based on available information from the site characterization
report. Examples of situations in which tentative identification might occur include: a specific
contaminant named in a threat; tentatively positive results for a specific contaminant during field safety
screening or rapid field testing; physical evidence at the site pointing to a specific contaminant; and
clinical evidence of the identity of the disease causing contaminant.  It is important to note, however,
that each of these situations has a different level of credibility for the purpose of tentative
identification. In general, tentative identification may focus the analytical approach  on the specific
contaminant subclass, leading to confirmatory analyses for the particular contaminant. For example,
tentative identification of a class of pesticides (e.g., organophosphates) may be based on results from a
test kit, and this information might be used to focus the analytical approach on specific pesticides
within that class.  Depending  on the strength of the tentative identification, as determined with due
diligence by the water utility emergency response manager, it may be wise to consider heading down
both paths simultaneously (Module 2). If the evidence for tentative  identification is  sufficiently strong,
then screening may be delayed. Otherwise, screening for a broad array of potential contaminants
should begin simultaneously with the confirmatory analysis for the tentatively identified contaminant.

The third decision point is based on the results of the confirmatory analysis used for the tentatively
identified contaminant.  If the presence of the contaminant was analytically confirmed, then the results
are reported to incident command.  In the case of potential multiple  contaminants, multiple analyses
may be required before incident command  decides if the analysis is  complete. (Note: For the purpose
of this document, analytical confirmation refers to the legally defensible identification of an analyte.
There are efforts in the analytical forensic community to rigorously  define what constitutes
confirmation, and results of these efforts may be included in later versions of this module.  In the
interim, laboratories should pay careful attention to principles that govern the admissibility of scientific
evidence [Section 3.5].)

The fourth decision point involves the possibility of additional screening for chemicals or biologicals if
the presence of the tentatively identified contaminant was not confirmed or additional contaminants are
suspected. At this point, communication between the laboratory and incident command will likely be
necessary, because the decision to perform additional screening may be based on recently available
information regarding the threat.  For example, new  evidence may come to light indicating that, despite
initial indications, the threat is no longer credible. However, in case the threat is still deemed  credible,
it may be necessary to revise and/or expand the analytical approach, possibly in conjunction with a
fresh review of the site characterization report.

In any situation involving tentative identification of a contaminant, the reliability of the information
should be carefully evaluated. In some cases, it may be determined  that the source of information is
too unreliable to provide the basis for a tentative identification. For example, if a specific contaminant
is named in a threat made over the phone, the reliability of the information might be  considered
suspect. In this case, the analytical approach might start with the named contaminant, but additional

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screening might be warranted depending on other considerations such as the credibility of the incident.
For this reason, development of the analytical approach may be iterative, as indicated by the decision
point "Is additional screening necessary?" If the answer to this question is "yes," available information
would be reevaluated to refine or broaden the analytical approach.
5.2  Initial Assessment of Available Information
While previous water contamination threats may indicate that the most likely scenario is an unknown
contaminant, it is possible that there may be some information from the incident that may inform the
development of the analytical approach.  For example, negative results from reliable field tests may
eliminate some contaminant classes from further consideration. Likewise, information from the site
characterization report may be useful in tailoring the screening to the specific situation. Even if the
available information is insufficient to make a tentative identification at the grossest level (i.e.,
chemical or microbiological), it still  may be of value during application of the screening.

The first step of the process shown in Figure 4-4 is an evaluation of available information from the
current threat that might provide clues about the identity of the suspected contaminant. Information
that should be  considered in developing an analytical approach for a specific contamination threat
includes the following:

   •   Public health information may be available if exposed individuals seek medical attention, and
       the clinical data for these patients may provide insight regarding the identity of the
       contaminant.  Such information may be used to make a tentative identification of the
       contaminant or contaminant class, and in some cases might provide definitive identification.  It
       is important to note that even though exposure has occurred, it does not necessarily imply that
       drinking water is the source of the contamination; other routes of exposure, such as food, air, or
       surfaces might be considered depending on the situation.

   •   Tentatively positive results from field testing may be used to tentatively identify a specific
       contaminant or contaminant class. Negative results may be used to exclude certain
       contaminants from further consideration. The credibility of the field test results must be
       evaluated in the context of the reliability of the field test equipment and procedures.

   •   Physical  evidence at the site may provide insight regarding the identity of the contaminant.
       For example, empty containers might have markings indicating the nature of the contaminant,
       and analysis of the residual material in the container may confirm the identity of the substance.
       Other physical evidence from the site, such as dead animals or plants, might be used to
       formulate a hypothesis about the identity of the substance, and thus inform the analytical

   •   Information about a specific contaminant from a database or fact sheets may be used to
       make a tentative identification of the suspect contaminant.  For example, field screening results
       and/or  physical evidence might be used in conjunction with detailed information about
       potential  contaminants to make a tentative identification of the contaminant or contaminant

   •   Location-specific contamination threats should also be considered during development of an
       analytical approach for a specific contamination threat.  For example, utilities may have

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       identified potential contaminant sources (e.g., chemical warehouses) during their vulnerability
       assessment, and such opportunity contaminants might be explicitly included in the analytical

   •   Background concentrations of the specific contaminant at the site may be extremely
       important in determining if a contamination incident has occurred.  In some cases and for some
       contaminants, background levels may be at detectable concentrations.  If unrecognized,
       background concentration of a contaminant may be confused with an actual
       contamination incident.

   •   Threat credibility may provide an indication of the severity of the incident, and thus may
       indirectly impact the analytical approach. For example, if a threat is deemed highly credible,
       then complete screening for both chemical and biological contaminants might  serve as the
       analytical approach regardless of other information collected from the site.

   •   Consequences of failing to properly identify an  unknown contaminant (or not confirming the
       absence of harmful contaminants) should also be considered in developing an analytical
       approach.  The higher the potential consequences of a misdiagnosis of the incident, the more
       rigorous the analytical approach should be.

5.3   Overview of Analytical Approach For Unknowns
In the case of a complete unknown, the problem of confirming the presence/absence of a contaminant
or identifying and quantifying a specific contaminant presents a significant challenge. The difficulty
arises from the large number of potential contaminants of concern, and the impracticality of screening
for them all. To address this issue, the analytical approach for unknowns was based on contaminant
classes derived from a prioritization of chemicals and pathogens of public health concern if present in
the drinking water supply.  The approach used to prioritize potential contaminants is briefly discussed
in Section 2.1 of Module 1.

The analytical approach for unknown contaminants in water presented in this module  is comprehensive
for selected, priority contaminants and provides coverage for hundreds of additional contaminants not
on this list. The following assumptions and principles were used in the development of these
   •   Selection of target analytes was based on an assessment of contaminants likely to pose a threat
       to public health if introduced into the drinking water supply.
   •   Existing laboratory infrastructure and analytical  methodologies were utilized when possible.
   •   Both chemical and microbiological procedures are tiered, with a progression through field
       safety screening and rapid field testing to laboratory testing to confirmatory analysis.
   •   Samples analyzed in a laboratory that cannot be  confirmed by the laboratory performing the
       test are referred to laboratories that can perform  a confirmatory analysis. This upward referral
       system is formalized for microbiological analysis, through the Laboratory Response Network,
       while it is not as well defined for chemical analysis.
   •   The entire approach relies on the systematic elimination of potential contaminants, both to
       ensure the safety of sampling and laboratory personnel, and to aid in identification of the
       unknown contaminant.
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Considering the principles and assumptions upon which the comprehensive analytical approach is
founded, it is likely that the approach may evolve as new methodologies are developed and refined.
Furthermore, laboratories with advanced capabilities may wish to implement alternative procedures
that either expand coverage or streamline the analysis.  Such modifications would be acceptable
assuming that they provide at least equivalent coverage of target analytes compared to the standard
approach and meet the data quality objectives of the analysis, such as legal defensibility of data. The
comprehensive analytical approach in this module should serve as a baseline against which any
alternate approach should be compared.

It is also important to realize that identification of unknown contaminants in water samples is not an
exact science. There should be no expectation than any combination of technology and analytical
personnel will guarantee successful identification of unknown contaminants. However, application of
appropriate technologies and training of laboratory personnel will likely increase the probability of
success.  The successful identification of an unknown is dependent upon the skill of the laboratory
personnel and the laboratory having appropriate analytical technology. With the many types of
analytical techniques and methods in existence, it is likely that no one analyst, no matter how skilled,
can use all these techniques and methods. A more thorough identification of unknown contaminants
may involve a team of chemists and microbiologists to provide consultation  and/or perform various

Since the procedures and laboratories used for the analysis of chemical and microbiological
contaminants are significantly different, discrete  analytical screening procedures have been developed
for each. The screening for chemical contaminants is presented in Section 6, while the screening for
microbiological contaminants is presented in Section 8. These procedures are briefly discussed in the
following subsections.

Not only may different laboratories be involved in the analysis of chemical and microbiological
contaminants, but some select analyses or extreme hazards should be handled only by a limited number
of specialized laboratories.  Since different laboratories may be involved in implementation of the
analytical approach for a specific water contamination threat, communication and coordination among
the various laboratory personnel involved in the analysis of an unknown sample is critical.  For
example, other laboratories should be made aware of potentially harmful  contaminants revealed by
other laboratories.  This may be vital to the safety of the laboratory personnel as well as the
expeditious identification of unknowns.

5.3.1  Screening for Chemicals, Including  "Unknowns"
Screening for chemicals, including "unknowns,"  is described in detail in Section 6.  Because the target
audience for Section 6 is laboratories, the following overview is presented for the benefit of planners
and managers. In summary, the chemical screen integrates several analytical techniques to cover a
broad range of chemical classes.  These analytical techniques include not only wet chemistry and
instrumental analysis, with which laboratories  are typically familiar, but also various hand-held
equipment and commercially available test kits, such as those based on immunoassays.

The overall screen is broken up into two parts, one referred to as a basic screen and the other as an
expanded screen.  The suite of techniques utilized in the expanded chemical screen is comprehensive
for all prioritized contaminants of concern discussed in  Section 6.1.1. Furthermore, the screen  may be
capable of detecting hundreds of additional chemicals that were not identified as high priority, but

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could still pose some problem if used in an intentional contamination threat or incident.  It is important
to note that the screens are not prescriptive and labs have a great deal of flexibility in building an
analytical approach that is consistent with their existing capabilities and experience while meeting the
needs of their clients.  However, it is strongly recommended that screening for chemicals encompass a
wide range of possible contaminants given the large number of chemicals potentially available.  See
Section 6.1 for more details.

The basic screen utilizes established analytical techniques in conjunction with legally defensible,
standardized methods for the analysis of contaminants in water. However, these established
techniques do not provide complete coverage for all target analytes.  For instance, currently there are
no standardized methods for analysis of the biotoxins of concern in water.  To address these gaps,
exploratory techniques, which do not have standardized methods, are used in the expanded screen.  For
instance, immunoassays or liquid chromatography-mass spectrometry may be incorporated into the
expanded screen to cover biotoxins.  Of the many analytical techniques available, the ones utilized in
the expanded screen are those that may show the most promise for water analysis.  Particularly, those
that have established applications in media other than water provide a basis for inclusion in the
expanded screen.

In the screening procedure,  analysis  of contaminants is divided into chemical classes, such as organic,
inorganic, and radionuclides:
   •   Organic analyses utilized in this approach are comprised of some combination of the following
       three steps: 1)  extraction or recovery of the contaminant from the aqueous matrix, 2) separation
       of the compounds through gas chromatography or liquid chromatography; and/or 3) detection
       and identification  of the analyte. Preparatory and extraction techniques for organic constituents
       should be broad enough to recover a variety of compound classes (e.g., a range of hydrophilic
       properties and molecular weights).  A variety of techniques are used for detection of organic
       constituents. When mass spectrometry is used for detection, qualitative identification may be
       realized through electron ionization mass spectral library comparisons.
   •   The inorganic  analyses include several analytical techniques: classical wet chemistry and
       instrumental techniques such as inductively coupled plasma mass spectrometry, inductively
       coupled atomic emission spectrometry, atomic absorption spectrometry for trace metals, and
       ion chromatography for anionic and cationic contaminants.
   •   The analysis of radionuclides during an emergency incident relies on conventional radiological
       techniques, but falls into a  separate paradigm than other chemicals because radionuclides may
       be characterized by both the type of radioactivity they emit as well as specific radioisotopes.

Figure 4-4 illustrates an important issue in  the screening for unknown chemicals, namely that
confirmatory analysis may be required in the case of a tentatively identified chemical. In general, a
positive result from a rapid field test or safety screening (performed in the field or laboratory) would
be considered tentative identification and require independent confirmation. By contrast, chemicals
identified through the application of standardized methods typically do not require independent
analytical confirmation because recommended confirmatory steps are often incorporated into the
methods themselves.   In some cases, another laboratory with specialized capability may need to
perform the confirmatory analysis. For instance, confirmatory analyses for chemical weapons would
be performed only in few established laboratories designed and permitted to work with these
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When possible, confirmatory analyses should be performed using existing standardized methods
accepted for analysis of the target analyte in a water matrix.  When a standardized method is
unavailable, confirmatory analysis may need to be performed through application of methods that rely
upon different separation and/or detection techniques as a means of independently verifying the
identity of a chemical contaminant.

5.3.2  Screening for Microbiologicals, Including "Unknowns"
The microbiological screen is designed to recover several classes of organisms, including parasites,
bacteria, and viruses.  Furthermore, the approach may recover some high molecular weight biotoxins,
such as botulinum toxins. The four basic steps of the microbiological screen include: 1) concentration
and recovery in the field; 2) rapid field testing; 3) testing at a Sentinel laboratory; and, if needed, 4)
testing at a Reference laboratory.

To obtain the detection limits necessary to provide results from microbiological analysis that are
meaningful from a public health perspective, it is often necessary to concentrate the water sample by
several orders  of magnitude (e.g., 100 liters concentrated to 100 milliliters). In the microbiological
screen (Section 8), concentration is performed by ultrafiltration, a physical separation process capable
of complete retention  of parasites, bacteria, viruses, and potentially some large molecular weight
biotoxins. Ultrafiltration is capable of processing large volumes of finished water in a short period of
time, while continuously concentrating pathogens and other suspended solids in the retentate.  The
accumulated material  is then removed from the membrane through mechanical or chemical means and
collected as a retentate.  This low volume retentate may be then subjected to microbiological analysis,
so it should be handled with appropriate caution to ensure the safety of the sampler and the viability of
any organisms collected.

The rationale for performing this concentration step in the field as an integral part of sample collection
is based on two considerations. First, containers approved for the shipment of large volumes of liquid
suspected of containing select pathogens do not exist; thus there may be no effective means of quickly
transferring a large water sample to another facility for processing. Second, concentration of
microbiological contaminants in the field allows for the useful application of field screening devices
(e.g., pathogen field test kits), the next step of the microbiological screen.

After concentration, the concentrated sample is divided into three aliquots. Two of these  aliquots are
packaged for shipment to the laboratory, while the third may be used for field testing.  The method for
field testing will depend on the technology utilized, but in the case of pathogen field test kits, a small
volume of the  concentrate may be directly applied to the pathogen field test kit, followed by a short
reaction period and evaluation of the  test result.  A positive result should be considered tentative, and
the information used accordingly in the context of the overall threat evaluation.

The remaining two aliquots are sent to a laboratory, such as an LRN Sentinel Lab, capable of
performing tests for tentative identification of target pathogens. One aliquot may be used to perform
culture techniques for the target pathogens.  If the initial results of the culture method are analyzed,
and colonies of a particular morphology are considered tentatively positive, they are forwarded to an
LRN Reference laboratory.  The  second aliquot may be used for PCR and subsequent molecular
analysis for target pathogens, which will provide more rapid, yet still tentative, results compared to the
culture technique.  However, molecular assays do not necessarily produce specimens that can be
forwarded on to LRN Reference laboratories for confirmatory analysis.  It is important to note that

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LRN PCR techniques for select agents may not be performed by Sentinel labs, although Sentinel labs
can perform certain non-LRN PCR techniques.

Upon tentative identification of a target pathogen, the suspect cultures are isolated and processed for
referral to higher level LRN laboratories capable of confirming the presence of select pathogens
through a combination of culture and PCR techniques. Once the sample enters this level of the LRN,
the existing network, and methodologies will be utilized to further characterize the pathogen.
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6   Analytical Approach for Chemical Contaminants

6.1   Overview of Contaminant Issues

6.1.1   Types of Chem ical Contam inants Covered by the Analytical Approach
Module 1 of this Toolbox provides an overview of the nature of intentional contamination threats that
drinking water facilities might face. Water from the drinking water distribution systems is considered
the most significant vulnerability, as opposed to raw source water or wastewater.  The focus of the
analytical approach in this section is on approximately 35 specific contaminants, selected from a list of
chemicals, biotoxins, and radionuclides, prioritized based on the contaminant's potential threat to
public health from a national perspective (see Module 1). General water quality parameters from
distribution systems (pH, turbidity, chlorine residual,  total organic carbon, etc.) are discussed in terms
of site characterization (Module 3, Table 3-2).  These general water quality parameters are potential
indicators of chemical contamination at best, and may not cover all of the contaminants of concern.

The approximately 35 specific contaminants are not necessarily listed in this module or in Table 1-1  of
Module 1. There are several reasons for this.  First, it may not be advisable to specifically list these,
since  such information could be used with malicious intent.  Second,  a particular contaminant may be
very important in a particular locality, but not have been included on  the national priority list.  Third,
as part of fulfilling the goal of due diligence in providing a comprehensive screen (Section 1.2.2), it is
necessary to include other chemicals in the analytical  approach that encompass a broad range of
effects, not just those that may have the highest public health impact.

The approach taken in this module is to divide potential contaminants into classes based on their
analytical grouping (i.e., how contaminants with similar properties are analytically determined).  This
helps  to limit the number of methods to those that encompass the largest number of analytes. The
chemical types, resulting analytical groups, and examples of specific  contaminants, are shown in Table
4-1. Suitable analytical methods are discussed further in Sections 6.4 and 6.5.

Table 4-1.  Summary of Types of Chemical  Contaminants, their Analytical Group, and the Class
of Contaminants Determined by the Analysis
CW Agents
Analytical Group
Carbamate compounds
Quaternary nitrogen compounds
Trace metals
Schedule 1 only**
Example Contaminants*
Acetone, acrylonitrile, chloroform, methyl /-butyl ether,
tetrachloroethene, toluene,
Organophosphates (e.g., malathion, mevinphos, dichlorvos, etc.),
cyanazine, chlorinated insecticides, chlordane, pentachlorophenol
Sodium trifluroacetates, surfactants
Aldicarb, carbofuran, oxamyl
Diquat, paraquat
Nicotine, illicit drugs
Mercury, lead, cobalt
Arsenic salts
Organomercury compounds
Cyanide salts, cyanogen chloride
Cesium-137, Cobalt-60, Strontium-92
(e.g., VX, sarin, nitrogen and sulfur mustards, Lewsites)
* Not every contaminant in a particular analytical group is listed in this column.
**See Section 2.1.4 for a discussion of Schedule 1 agents.
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6.1.2  Selection of Appropriate Methods for Contaminant Analysis
As described in Section 5 of this module, there are two general approaches to the chemical screen.
One approach is referred to as the "basic" screen, while the other is referred to as the "expanded"
screen.  Together, they are a comprehensive screen for the 35 priority contaminants and also provide
coverage for hundreds of other potential water contaminants, although it is not feasible (or necessary)
to determine all of the hundreds of thousands of chemicals in existence. Fewer laboratories may be
capable of implementing the expanded screen (Section 6.5).

It must be emphasized that this module  along with Sections 6 and 8 are not intended to represent a
prescriptive "how-to" laboratory manual.  Rather, the model screening procedure (Sections 6.3-6.5,
8.1) is intended to be a planning tool for laboratories to formulate a laboratory guide specific to their
needs and capabilities.  For instance, the basic screen presented in Section 6.4 is composed of
relatively reliable and accessible techniques, which hopefully will encourage more laboratories to
develop some screening capability for potential harmful chemical contaminants (i.e., beyond
regulatory requirements). However, planners may not wish to employ any elements of the basic
screen, but rather rely only on techniques used in the expanded screen (Section 6.5), backed up by
suitable analytical confirmation to ensure defensibility of the results.  Planners must exercise due
diligence in planning their analytical approach, as well as all other response activities, to protect public
health and safeguard the water supply.

For the selection of appropriate methods to include in the screen, it is important to realize that planning
is a vital part of site-specific response to a contamination incident. In many cases, planning  for the site
characterization (Module 3) will drive the selection of methods. In some  cases, it may be  desired only
to identify the contaminant, but accurate quantification may be necessary  in others.  Depending on the
specific plan, various goals and analytical methods may be applicable.

An intentional contamination incident may produce contaminant concentrations ranging from
extremely high (milligrams per liter), when much contaminant is added to a relatively small  amount of
water, to very low (low to mid microgram per liter), as in the tail of a transient contaminant slug in a
drinking water distribution pipe.  Accordingly, the analytical methods described in this approach were
selected to be conservative and reflect the goal of defensibly determining  lower concentrations of
chemicals.  This great variability in analytical needs that may arise in each threat/incident  is another
reason that this section is not a prescriptive "how-to" manual.

6.1.3  Initial Processing of Contaminants prior to Laboratory Analysis
Regardless of the type of screening that the laboratory uses, it is likely that laboratories will  receive
samples that have been characterized to some extent, and perhaps tentatively identified, at the site.
Figure 4-5 indicates the types of laboratories that might analyze emergency water samples. The site
hazard assessment performed during site characterization will help the water utility emergency
response manager (or the designated incident commander) decide which laboratories to use for a
particular sample set. If a chemical contaminant has been tentatively identified in the field, it may aid
in the selection of an appropriate laboratory.  It will be necessary to then apply specific analytical
techniques to confirm its identity and/or quantify the concentration.  Otherwise, the sample may be
subjected to a screening procedure, which is described in more detail below.  Note that the screening
procedure box does not explicitly list radionuclides, since radionuclide analysis involves a different
paradigm, as discussed in Section 6.4.8, below.  Also, some radionuclide  screening is performed upon
receipt by the laboratory as discussed in Section 3, in addition to the field screening in Section 4.

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                             Specific chemical
 Perform Screening for
Chemical Contaminants
                           Perform Confirmatory
Figure 4-5. Initial Analytical Approach to Processing Samples with Chemical Contaminants
* Specialty labs include the LRN and those only accessible through law enforcement (e.g., CW labs).

At the starting point for Figure 4-5, the contaminant identity is hypothesized based on available
information from the site characterization report. Examples of situations in which tentative
identification might occur include: a specific contaminant named in a threat; tentatively positive results
for a specific contaminant during field safety screening or rapid field testing; physical evidence at the
site pointing to a specific contaminant; and clinical evidence of the identity of the disease-causing

It is important to note, however, that each of these situations has a different level of credibility  for the
purpose of tentative identification (Module 2) and that additional contaminants may be present. In
general, tentative identification may focus the analytical approach on the specific contaminant
subclass, leading to confirmatory analysis for the particular contaminant.  For example, tentative
identification of a class of pesticides (e.g., organophosphates) may be based on results from a test kit,
and this information might be used to  focus the analytical approach on specific pesticides within that

In most cases, it is anticipated that a specific chemical contaminant will not be identified with
sufficient reliability to be considered tentatively identified, and it will be necessary to conduct
screening for potential chemical contaminants. Depending on the strength of the tentative
identification, it may be wise to consider heading down both paths of Figure 4-5 simultaneously. If the
evidence for tentative identification is sufficiently strong, and if there are no other contaminants
suspected, then screening may be delayed.  Otherwise, screening should begin simultaneously with the
confirmatory analysis, as described in the Section below. At the other extreme, during a 'confirmed'
incident, the contaminant will  likely be known, and the point of analysis in this case is to further
characterize the contaminated  area to support the planning stage of remediation and recovery.
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6.2   Confirmatory analysis
It is necessary to confirm the identity and/or concentration of a contaminant identified either in the
field or in the laboratory. In the case of a tentatively identified chemical contaminant, Figure 4-5
indicates that one of several types of distinct, specialized laboratories might be involved in conducting
confirmatory analysis. The functions of these laboratories are described in more detail in Section 2.1
as part of the infrastructure discussion. Some confirmatory analysis may only take place in specialty
laboratories, such as those for Schedule 1 CW agents. A discussion of these techniques and the
associated equipment is beyond the scope of this document since these laboratories presumably have
established procedures for these specialty analytes, and an overview of these techniques would not be
particularly helpful to the target audience for this document. In addition, access to these laboratories is
restricted and must be made by the appropriate authorities.

For radionuclides, analytical confirmation may be viewed differently than most chemicals because
radionuclide analysis can take the form of screens for gross alpha, beta, or gamma radiation, and/or it
can take the form of analysis for the specific radionuclides themselves, such as strontium-90.  Thus,
analytical confirmation may involve the process of confirming quantity of gross radiation or
identifying the radionuclide. The type of analysis that is performed will be based on the analytical
goals.  For example, radionuclides in drinking water regulation are often characterized by their gross
alpha and gross beta emissions.  For the purpose of emergency analysis of water contaminants, a tiered
approach is suggested, with screening for gross radiation in the field or upon receipt by the laboratory
followed by identification of the radionuclide, which may be important for a more complete
understanding of risks to public health as well as potential criminal actions against perpetrators.

On the other hand, many environmental chemistry laboratories can confirm a significant number of
chemical contaminants through the use of a variety of standardized methods. In the context of this
module, standardized methods are produced as a standard by a recognized method development
organization (EPA, ASTM, AOAC, ISO, etc.) and contain valid steps to defensibly confirm the
presence and/or quantity of specific contaminants. For the analysis of emergency water samples, a
standardized method need not be promulgated for compliance monitoring of drinking  water samples.

Environmental chemistry laboratories are often familiar with promulgated, standardized methods and
may have the equipment and expertise to perform  confirmatory analysis using such standardized
methods. A number of standardized methods are published by various organizations,  and may be
selected from an appropriate method database, such as the National Environmental Methods Index
(NEMI, http://www.nemi.gov). NEMI contains methods reviewed and selected by the National
Methods and Data Comparability Board (http://wi.water.usgs.gov/pmethods/), a partnership of water-
quality experts from Federal agencies, States, Tribes, municipalities, industry, and private
organizations. The Board provides a framework and forum for comparing, evaluating, and promoting
monitoring approaches for water quality.  Methods are available in NEMI to support the analytical
approach for the priority chemical contaminants, and a laboratory can use the NEMI database to select
a confirmatory method for a particular chemical contaminant based on its particular expertise and
equipment. NEMI is searchable by analyte, and a search will often return several methods for the
same analyte, developed to meet a variety of needs.  For example, some methods are EPA drinking
water methods,  some are EPA SW-846 methods, and some were developed by USGS  or DOE for their
environmental monitoring programs, etc.

Although consulting NEMI first is recommended, there  are other sources of standardized methods,
some of which are shown in Table 4-2. There are other comparable standardized methods available
from standards setting organizations like ASTM (http://www.astm.org), AOAC (http://www.aoac.org),

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and ISO (http://www.iso.org/).  In choosing a method, keep in mind that some of these standardized
methods may be prescribed for a specific intended purpose, such as drinking water compliance
monitoring.  However, in the context of this module, the methods are not prescribed, because there is
no regulatory driver for doing so.  Rather, all of these methods resources are to be used as planning
tools to assist laboratories in selecting methods for use in implementing the analytical approach
presented in this module prior to analyzing actual emergency water samples. For many laboratories,
planning may be simplified through the use of methods they are already familiar with, such as EPA
drinking water and SW-846 methods.

Table 4-2.  Sources of Standardized Methods
National Environmental
Methods Index (NEMI)
Recently developed US
EPA methods
EPA SW-846 methods
EPA drinking water
40 CFR Parts 136 and 141
Standard Methods for the
Examination of Water and
Wastewater, 20th edition
(January 1999)
Other recognized method
development organizations
Contains methods compiled from
many sources. May be consulted
Contains current revisions of
promulgated methods for
drinking water analysis with notes
Mainly for solid waste, but many
are applicable for drinking water,
using appropriate preparation
Printed versions of drinking water
Promulgated list of defensible
methods widely accepted in the
analytical community for water
and wastewater.
Various methods covering the
range of water analytes.
May provide comparable methods
US EPA and
US EPA Office of
US EPA Office of
Research and
US EPA Office of
Solid Waste

American Public
Health Association
and American
Water Works
How to obtain
http : //www. epa. go v/safewater/met
http : //www. epa. go v/nerlc www/ord
For ordering details, see
http : //www. epa. go v/nerlc www/met
chapt-I . info/subch-D .htm
Available from most booksellers.
ISBN: 0875532357
http : //www. astm. org
If standardized methods are not available for the contaminant of interest, then analytical confirmation
may involve the techniques described below for basic and/or expanded screening (Sections 6.3 and
6.4). In this situation, the requirements for analytical confirmation are generally not well defined and
are further complicated by the issue of legal defensibility of scientific data. Section 3.5 of this module
provides an overview of rules that govern the admissibility of scientific  evidence into a court of law
and points out the pitfalls associated with using methods that have not been standardized. There are
currently efforts underway in the forensic community to resolve these issues and develop standard
approaches for the analysis (including confirmation) of samples contaminated with an unknown
substance. While guidance from the forensic community is not available at this time, it may be
included in future versions of this module.  Ultimately, it may be the responsibility of laboratories to
take appropriate steps to support the admissibility of data produced using exploratory techniques that
have not yet been widely accepted in the scientific community (see Section 3.5).
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6.3  Laboratory Analytical Screening for Chemical Contaminants, Including
The laboratory analytical screening described here is different and separate from the laboratory
safety screening (Section 3.1.4 of this Module) and the field safety screening and rapid field testing
(briefly described in Section 4 of this Module and more completely in Module 3).  Briefly, the field
safety screening and rapid field testing were performed during characterization of the contamination
site, before any laboratory work is performed. The entire site characterization process is designed to
reduce risk to the  site characterization team and any individuals coming into contact with samples
collected from the site.  Site characterization activities are not limited to only field safety screening and
rapid water testing, which may only capture a few contaminants, but also include a site investigation
that may identify other signs of hazards. These  activities aid in the site hazard assessment and help
ensure that samples are sent to  a laboratory prepared to deal with both the analysis and any safety
issues.  For example, if pathogens are suspected, the samples should not be sent to an environmental
chemistry lab.

The overall concept of laboratory analytical screening for an unknown chemical in a water sample  is
presented in Figure 4-6.  This chemical screen consists of two core elements: 1) application of multiple
analytical techniques to screen for a wide range  of analytes; and 2) analytical confirmation of tentative
results. In the first core element, the combination of analytical techniques used to achieve broad
coverage of the contaminant classes of concern includes  both standardized methods and exploratory
techniques.  The standardized methods are derived from  those same sources as listed in Section 6.2.
Exploratory techniques are those that do not necessarily form the basis of standardized methods for
water analysis, but are capable of detecting chemicals that are not included in existing standardized
methods.  Both of these elements are implemented in the laboratory.

Two different chemical screens were constructed from the established and exploratory techniques.  The
first, indicated in Figure 4-6 as the "Basic Screen," (Section 6.4) uses only standardized methods, and
the method analytes include a  significant percentage of the priority chemical contaminants as well as
many other chemicals.  The second, referred to as the "Expanded Screen," (Section 6.5) combines
established techniques and exploratory techniques to achieve the broadest coverage, including all
priority chemical contaminants. Additionally, the Expanded Screen provides laboratories with
additional options regarding the instrumentation used to  implement both established and exploratory
techniques; however, the results may not be as definitive as those for established techniques.

The second core element in Figure 4-6 is analytical confirmation of the results. As shown in the
figure,  some methods utilized in the "Basic" screen contain required steps for defensible confirmation.
Some do not, and  other confirmatory analysis should be performed, as described in Section 6.2. As
shown in Figure 4-6, it also would be necessary to confirm the results of most exploratory techniques,
unless the technique is applied within a methodology that utilizes suitable validation procedures. The
strategy of using the variety of techniques in the "Expanded Screen" may lend itself to fulfilling the
requirements discussed in Section 6.2 for confirming an  analyte, particularly one for which no standard
method exists. For example, analytical confirmation may sometimes be accomplished through
determination of the contaminant by two or more analytical techniques that operate on independent
principles (e.g., LC/UV and GC/MS). In comparison, analytical techniques that operate on the same
principles (e.g., different immunoassays) may be unreliable for confirmation purposes and should be
used with caution.
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                                                                                               MODULE 4:  Analytical Guide
                                       Laboratory Screening for Chemical Contaminants
                                           Expanded Screen (Section 6.5, Table 6-4)
                   Basic Screen (Section 6.4, Table 6-3)
                                         Report Method

Micro LLE
Cont LLE

i 1


                                                                                               x  x
Report Confirmed
Figure 4-6. Overview of Screening and Confirmatory Analyses for Chemical Contaminants
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                                                          MODULE 4: Analytical Guide
6.4  Basic Screening using Established Techniques with Standardized Methods
     for Target Analytes
The basic screen is designed to capture many of the chemical contaminants of concern using a
relatively small number of well-defined analytical techniques. The techniques chosen for this basic
screening analysis are summarized in Table 4-3. This is to say, if the methods in Table 4-3 are
performed, then the screen may cover a large percentage of the priority chemical contaminants
(Table 4-1).  Furthermore, many other contaminants of concern, but of lower priority, may be
screened for as well. To increase confidence in the results, only standardized methods (e.g., EPA
drinking water, SW-846, or comparable methods) are used for the basic screen.  Comparability
involves analytes determined, detection limits, QA/QC, etc. See Section 6.2 for information about
comparable methods.

As discussed previously, EPA standardized methods are suggested mainly because many labs may
be familiar with some or all of these methods, and many laboratories are certified and/or accredited
to determine water contaminants using these methods. This increases the defensibility of the
results, since the laboratories would have experience in performing all of the required QC within
acceptable ranges. Also, in most cases, the use of EPA methods also means that if a method analyte
is determined by these methods, no further analytical confirmation would be necessary since many
of these methods contain confirmatory steps.  In choosing a method, keep in mind that some of
these standardized methods may be prescribed for a specific intended purpose, such as drinking
water compliance monitoring.  However, in the context of this module, the methods are not
prescribed, because there is no regulatory driver for doing so.

The  basic screen may serve as a springboard for more complete characterization of the
sample, in an "outside-the-box" manner. Namely, a significant advantage to using the
techniques in the Table 4-2, or comparable ones, is that many rely on chromatography and/or
mass spectrometry, so the data should be capable of being evaluated for the  presence of not only
target analytes, but also other compounds.  If a contaminant is discovered that is not in the
analyte list of the method used, the identification should be considered tentative until confirmed
(Section 6.2). In the absent of confirmation, expanded screening of the sample should be applied
(Section 6.5).

Information from the basic screen may also be used to inform the selection of exploratory
techniques.  For instance, if a target  analyte or unknown peak is not found in a Method 524.2
analysis, the compound is likely not a volatile organic; if no peak is present  in a Method 8270D
analysis, the unknown may be inorganic in nature or thermally unstable.
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Table 4-3.  Suggested Analytical Techniques for Performing the Basic Chemical Screen, broken
out by the classes given in Table 4-1.
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic, includes
many pesticides)
Carbamate pesticides (organic)
Quaternary nitrogen compounds
Trace metals (inorganic)
Total mercury (inorganic, includes
organomercury compounds)
Analytical Technique
Purge-and-trap PID/ELCD
Purge-and-trap GC/MS
Solid-phase extraction GC/MS
HPLC - fluorescence detection
graphite furnace AA
Cold vapor AA
Wet chemistry
Gross alpha, gross beta, Gross
EPA Method1
502.2, 8021B
524.2, 8260B
525.2, 8270D/3535A
200.7, 200.8,2 200.9
245. 1,245.2 with
900, or technique
preferred by lab3
Analyte List4
1. Method titles are listed in Table 4-19 in the appendix (Section 10)
2. Method 200.8 may be applied in the time-saving "direct analysis" mode that does not require digestion, if the
NTU of the water sample is <1. Note that the NTU of the water may be quickly determined in-house and/or may be
available in the site characterization report supplied with the sample.  The use of the scanning mode in Method
200.8 is also suggested
3. Many radionuclide laboratories have developed in-house methods for rapid screening ofradionuclides. These
may be similar to EPA 900-Series methods, which were developed for the measurement of very low, environmental
levels of radioactivity in drinking water but may require several days to obtain a result.  See Section 6.4.8 for
further discussion.  Analytical confirmation may be required via EPA Method or other defensible methods.
4. Standard may contain these. See Table 4-20 in the appendix (Section 10).

As mentioned in Section 1, this module is primarily intended for the purpose of planning an
analytical response. The users may wish to develop their own basic screen after evaluation of
their particular capabilities and experience as well as the needs and concerns of their clients.
(Some hypothetical examples of basic screens are given  in Section 7 of this module.)  For a
utility laboratory, the basic screen would be based on the utility's perception and knowledge
about threats in  their area and the capabilities of their laboratories. Because there is no
regulatory requirement to apply any basic screen, a laboratory may, in principle, choose not to
employ any of the standardized methods in Table 4-3. In this case, however, it would be prudent
from a public health perspective to employ an expanded screen based on exploratory techniques
capable of determining the analytes of interest, such as those listed in Table 4-20.

There are several  important notes about Table 4-3:
    •   Screening ofradionuclides involves a different paradigm than conventional chemicals.
        See Section 6.4.8 for details.
    •   The preparation method for 8270D listed is 3535A, based on solid-phase extraction.
        Separately funnel preparation for 8270D, or any other separately funnel method, is not
        included because separately funnels may release aerosols when vented, potentially
        increasing the risk of exposure for laboratory personnel, unless appropriate hoods and/or
        other control measures are employed.  Granted, separately funnel techniques  are safely
       used every day but, considering that other sample preparation methods (such  as 3535 A)
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sorbent tube is heated and backflushed with helium to desorb the trapped sample components
into a capillary gas chromatography (GC) column interfaced to a mass spectrometer (MS). The
column is temperature-programmed to facilitate the separation of the method analytes, which are
then detected with the MS. Compounds eluting from the GC column are identified by comparing
their measured mass spectra and retention times to reference spectra and retention times in a
database. Reference spectra and retention times for analytes are obtained by the measurement of
calibration standards under the same conditions used for samples. The instrument should be
calibrated for the analytes of interest, using analytes similar to those found in Analyte List A
(Table 4-20).

Some laboratories possess purge-and-trap instrumentation with a PID detector in series with an
ELCD detector. This combination provides the ability to determine most of the analytes in list
A. Because of the nature of the PID and ELCD detectors, however, they cannot necessarily
provide the additional level of information and analytical confidence as a mass spectrometer (see
Section 6.5.1 below). Accordingly, Methods 502.2 and 8021B are included primarily to increase
the number of laboratories capable of this analysis.
6.4.2  Semivolatiles (Organic)
Solid-phase extraction involves the removal of analytes from water onto a solid sorbent material
(based on EPA Method 525.2). Analytes, internal standards, and surrogates are extracted from a
water sample by passing 1 liter of sample water through a cartridge or disk containing a solid
matrix with a chemically bonded CIS organic phase (solid-phase extraction, SPE). The organic
compounds are eluted from the SPE cartridge or disk with small quantities of ethyl acetate
followed by methylene chloride, and this extract is concentrated further by evaporation of some
of the solvent.  The sample components are separated, identified, and measured by injecting an
aliquot of the concentrated extract into a high resolution fused silica capillary column of a gas
chromatography/mass spectrometry (GC/MS) system.

Compounds eluting from the GC column are identified by comparing their measured mass
spectra and retention times to reference spectra and retention times in a database.  Reference
spectra and retention times for analytes are obtained by the measurement of calibration standards
under the same conditions used for samples.  The instrument should be calibrated for the analytes
of interest, using analytes similar to those found in list B (Table 4-20).
6.4.3  Carbamate Pesticides (Organic)
EPA Methods 531.1 and 531.2 can be utilized to detect carbamate pesticides and degradation
products, namely the N-methylcarbamolyoximes and N-methylcarbamates. (Note that Method
531.1 requires a different preservative.)  Compared to the other EPA methods in the basic
screening analysis, EPA Methods 531.1 and 531.2 do not encompass many analytes.  It may be
worth noting that at least one chemical (aldicarb) in this class has an immunoassay test available
for screening  purposes.

This immunoassay is not recognized for compliance monitoring, so it is not included in the basic
screening analysis, but might be useful as a field test.  In Methods 531.1 and 531.2, the water
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       are available, it may be prudent for laboratories to consider not using the separatory
       funnel preparation method.
   •   The methods encompass many analytes. In terms of obtaining standards to use in
       conjunction with the respective methods, it may be helpful to focus on certain analytes.
       The analytes that may be included in the standard are identified in the appendix (Table 4-
       20) by the list number included in Table 4-3. Laboratories may wish to add analytes to
       those listed in the appendix, and may already be doing so (e.g., to meet local regulation).
       These analytes must meet the same QC acceptance criteria and be part of the overall
       quality systems in the laboratory, so that the added analytes are as defensible as the
       method analytes.
   •   The methods listed in Table 4-3 determine a number of analytes that probably would not
       be involved in a contamination incident (in addition to those that are priority
       contaminants). However, for the purposes of a screen, it is valuable to include some of
       the additional analytes that are picked up by the method, especially since there is no way
       to predict which contaminants might be used in a threat  or incident.
   •   The standardized methods listed in Table 4-3 do not include some analytes of concern,
       such as the biotoxins, chemical warfare agents, and pharmaceuticals.  This may be due to
       the fact that since these are not regulated compounds in  drinking water, there has been
       little impetus to develop methods for these analytes.  This may change, due to the
       inclusion of some algal biotoxins, namely microcystins,  in the Contaminant Candidate
       List (http://www.epa.gov/safewater/ccl/cclfs.html) and Unregulated Contaminant
       Monitoring Rule (http://www.epa.gov/safewater/standard/ucmr/main.html).
   •   The methods in Table 4-3 are not always the same ones  that are required for compliance
       with the Safe Drinking Water Act as amended. For instance, Method 551.1, which is
       used for compliance monitoring of some disinfection by-products, does not  encompass a
       sufficient number of chemicals considered as priority contaminants from an acute health
       effect standpoint. After all, disinfection by-products largely produce a long-term health
       risk, not the acute risk to human health that would be the most pressing concern during an
       intentional contamination threat/incident.

The following is a brief discussion of the analytical methods utilized in the Basic Screen, broken
down by the chemical classes listed in Table 4-1.  Many laboratories may be familiar with the
individual methods listed, as these are typically the EPA drinking water compliance methods.
However, the purpose of the module is not to insist that only EPA drinking water compliance
methods may be used. As mentioned above, there are other fine method sources, including, but
not limited to, those in Table 4-3. If these other methods are employed, they should be capable
of determining the analytes of interest (i.e., Table 4-20), and they should conform to the spirit
and intent of the methods described briefly below.
6.4.1  Volatiles (Organic)
Purge-and-trap concentration and analyses by GC/MS (based on EPA Method 524.2 or 8260B)
may be utilized to identify organic compounds that are volatile in nature.  To summarize the
method, volatile organic compounds with low water solubility are extracted (purged) from the
sample matrix by bubbling an inert gas through the aqueous sample.  Purged sample components
are trapped in a tube containing suitable sorbent materials.  When purging is complete, the
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sample is filtered and a 400-jiL aliquot is injected into a reversed-phase HPLC column.
Separation of analytes is achieved using gradient elution chromatography. After elution from the
HPLC column, the analytes are hydrolyzed to form a methyl amine, which is further reacted to
form a highly fluorescent derivative that is detected by a fluorescence detector.  The
derivatization procedure imparts specificity to the analysis, and a sample component is identified
by comparison of its retention time to the retention time of a reference chromatogram. If the
retention time of an unknown compound corresponds, within limits, to the retention time of a
standard compound, then identification is considered positive.  Because of specificity limitations
of fluorescent detectors, identification requires expert judgment when sample components are
not resolved chromatographically.

When peaks obviously represent more than one sample component, or any time doubt exists over
the identification of a peak on a chromatogram, appropriate alternate techniques should be
applied to identify the peak, such as the use of a second  chromatography column, several of
which are contained in the method.  SW-846 Method 832IB also employs HPLC instrumentation
for the analysis of carbamates, and it also describes the use of thermospray mass spectrometric
detection, possibly providing additional information about the target compound. However, for
technical reasons revolving around data interpretation, the thermospray  interface is considered
obsolete, and is in the process of being replaced
6.4.4  Quaternary Nitrogen Compounds (Organic)
EPA Method 549.2 is a high performance liquid chromatography (HPLC) method for the
determination of diquat and paraquat in drinking water sources and finished drinking water. In
the method, a volume of water sample is subjected to solid-phase extraction. The eluate from the
extraction device is separated through the use of liquid chromatography with UV detection. A
photodiode array detector may be utilized to provide simultaneous detection and analytical
confirmation of the method analytes.
6.4.5  Trace Metals (Inorganic)
a) Inductively Coupled Plasma Mass Spectrometry (ICP-MS).  EPA Method 200.8 provides
procedures for the determination of 21 elements in a single run and provides mass spectral
qualitative identification with significantly better detection limits than most standard
instrumental elemental analysis techniques. The method involves a sample preparation
procedure with a digestion step using nitric and hydrochloric acids, although there is an
alternative "direct analysis" for samples with turbidity less than 1 NTU, which is applicable to
many treated drinking water samples as they typically have turbidity less than 0.3 NTU.  The
method describes the multi-element determination of trace elements by inductively coupled
plasma mass spectrometry (ICP-MS).  Sample material in solution is introduced by pneumatic
nebulization into a radiofrequency plasma where energy transfer processes cause desolvation,
atomization, and ionization.  The ions are extracted from the plasma through a vacuum interface
and detected on the basis of their mass-to-charge ratio by a mass spectrometer. The mass
spectrometer may be operated in the "scanning" or the "single ion monitoring" mode.  While
detection limits are slightly less in the scanning mode, the use of the scanning mode offers
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benefits in terms of identifying non-method analytes. Details are discussed below in Section
6.5.2a, as part of the expanded screen.

It should be noted that Method 200.8 is designed for compliance monitoring, and if acidification
of the sample is not performed in the field, the method recommends that the sample be held  16
hours after acidification, prior to analysis. This may not be practical in responding to
contamination incidents. (See Module 3, Section 3.2, for more details on preservation issues.)
Acid addition in the field may result in the release of toxic gases, such as hydrogen cyanide,
depending on the nature of the contamination.  As a safeguard, sample preservation in the field
should occur only after the potential presence of cyanide has been eliminated through field
screening using devices such as portable colorimeters or probes. According to the procedures in
Module 3, sample collection should always follow field testing (including cyanide), so this check
should be automatic.  If cyanide is found, the speed of reporting of Method 200.8 analytes may
not be an issue since discovery of elevated cyanide levels would elevate the credibility of the
threat and prompt immediate response actions, which would provide additional time for careful
forensic analysis.

Because of the specificity and detection limits of ICP-MS for all the elements in Analyte List E
(Table 4-20),  it may be considered a superior technique for trace metal analysis. However, in the
interest of more laboratories being capable of performing trace metal screening, it should be
recognized that inductively  coupled plasma atomic emission spectrometry and graphite furnace
atomic absorption spectrometry are widely used for trace metal determination. Practitioners
should be familiar with the comparative advantages and disadvantages of the techniques for  trace
metal determination listed in Table 4-3, particularly regarding detection limits and interferences
for some of the analytes in Analyte List E (Table 4-20).

b) Inductively  Coupled Plasma Atomic Emission Spectrometry (ICP-AES).  While ICP-MS
is a trace elemental technique with excellent specificity and detection limits for some  of the
contaminants of concern, other trace elemental techniques are available in many laboratories and
may be used as part of the expanded screening procedure.  EPA Method 200.7 provides
procedures for the determination of 32 elements in a single run through the use of ICP-AES.
ICP-AES is sometimes referred to as ICAP (for inductively coupled argon plasma) or ICP-OES
(for optical emission spectrometry). The instruments measure the atomic line emission spectra
by optical spectrometry. The aqueous sample is acidified  prior to instrument analysis. The
analysis begins with a nebulization and the aerosol stream is transported to the plasma torch,
which may be viewed by an optical spectrometer either head on (radially) or from the side
(axially) depending on the instrument. Each orientation provides different performance
characteristics, particularly in terms of interferences and detection limits, but each of these is
dependent on the matrix as well as the instrument design.  The speed of the analysis is also
influenced by instrument design.  For example, the optical system may allow either sequential or
simultaneous  determination of the analytes, with the simultaneous determination allowing faster
analysis; it also  may allow tentative identification of non-method analytes, similar to ICP-MS

c) Atomic Absorption (AA) Spectrometry. Graphite furnace atomic absorption spectrometry
(EPA Method 200.9) can also be used for a select number of metals.  The acid-digested sample is
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placed in the instrument and is pretreated prior to atomization. The atomization occurs after a
purging with an inert gas and drying. The atomization is performed by rapid heating and
produces an atomic cloud.  The atomic cloud then absorbs the element-specific atomic emission
from a hollow cathode lamp or electrodeless discharge lamp.  Instrument design influences
performance characteristics, like detection limits and number of elements that may be analyzed
at one time.  The atomic absorption technique may be used with other introduction techniques
than graphite furnace, as shown in the next section for total mercury.
6.4.6  Total Mercury (Including Organomercury Compounds)
EPA Methods 245.1 and 245.2 allow the determination of total mercury, which includes
inorganic mercury and many organomercury compounds, following digestion with potassium
persulfate, which oxidizes the  organomercury compound to mercuric ion before measurement.
The total mercury is determined through the use of cold vapor atomic absorption. This technique
greatly enhances the detection limit for mercury determination and offers other benefits as well.
Total mercury may be determined as part of the trace metal analysis using methods in Table 4-3
(Section 6.4.5), except GFAA, Method 200.9. However, Methods 245.1 and 245.2, which form
the basis for the dedicated mercury analysis instruments currently found in many laboratories,
were included here.
6.4.7  Cyanides
Ideally, the core field testing recommended in Module 3 will detect the presence of cyanide, so
laboratory analysis of cyanide would most likely serve a confirmatory role.  Depending on the
nature of the field test, it may use similar chemistry to the EPA Methods 335.2, 335.3, and 335.4,
as described below, but typically the field test will not employ distillation.  Thus, the field tests
primarily detect free cyanide ion (not cyanide complexes).

It should be noted that most cyanide field tests are designed for quantitative analysis of cyanide
at low levels (near the MCL), and they typically provide only a qualitative indication of the
presence of high cyanide concentrations.  Accordingly, it may not be necessary to perform
redundant tests in the laboratory, although it may be deemed prudent to do so. Such decisions
may be based on the concentration of cyanide in the water or the form of cyanide known or
suspected.  For instance, a titration procedure for cyanides is used when the concentrations
exceed 1 mg/L (EPA Method 335.2).  A reflux distillation is used to release the cyanides, which
are then absorbed in a scrubber solution. The titration uses a silver nitrate solution to titrate
cyanide in the presence of a silver sensitive indicator. For lesser concentrations, cyanide in
water is determined through the use of colorimetry (EPA Method 335.3 and 335.4). UV
digestion and distillation are used to convert the cyanides to hydrogen cyanide. Cyanides are
then converted to cyanogen chloride and then subsequent reactions with pyridine and barbituric
acid give a red colored complex.

The form of cyanide added to water may be important in deciding on which cyanide test is
appropriate for use. Free cyanide in water may result from the addition of soluble cyanide salts
or water-soluble organic cyanogenic compounds. Methods 335.2, 335.3, and 335.4 measure total
cyanide, which could be a mix of free cyanide, complexed cyanide, and some organic
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cyanogenic compounds.  Because free cyanide is the most toxic, without knowing the
concentrations of the other forms, which have widely varying toxicity, the use of the total
cyanide concentration would be conservative with respect to public health implications.

6.4.8  Radionuclides
Basic screening for radionuclides represents a somewhat different paradigm than conventional
chemicals because radionuclides can be characterized by both the type of radiation they emit as
well as their exact chemical identity.  Accordingly, initial screening for radionuclides may
involve an examination of gross radioactivity. However,  any initial screening that indicates the
presence of a radionuclide should be followed by analytical confirmation of the chemical
identity. A schematic for radionuclide screening is shown in Figure 4-7.  Note that in Section 3,
screening for radioactivity upon sample receipt is recommended. Accordingly, the decision
point in Figure 4-7 that asks "Does lab policy require screening for radioactivity?" provides
flexibility for local planning decisions.
                           Perform Field Testing
                             for Radioactivity
                            Field test positive for
                            Perform Laboratory
                           Screening Analysis for
                          Alpha, Beta and Gamma
                           Radiation (Table 6-3)
                                               Additional Analysis for
                                                 Radionuclides not
                            Perform Analysis for
                           Specific Radionuclides
Figure 4-7. Schematic for Basic Radionuclide Screening

The results of field testing for radioactivity (Figure 4-7) must be compared to background levels
to determine whether the site may have been contaminated with radioactive material. Although
discussed in Module 1, it is worth noting here that EPA has developed protective action
guidelines for radiation levels in water
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The analysis for gross alpha and beta radiation (EPA Method 900.0) may be conducted as a
screening method for alpha and beta particle activities in water and used to determine if specific
radiological analyses are needed.  Preliminary analysis can first be conducted in the field using
appropriate field portable or hand-held devices, but may be verified in the laboratory.  EPA
Method 900.0 can measure alpha particles with energies above 3.9 megaelectronvolts (MeV) and
beta particles with energies above 0.1 MeV. In this method, the water sample is evaporated and
dried, and the dried residue is counted for alpha and beta by a gas flow proportional counting
system or scintillation detector system. Note that as part of their safety plan, laboratories may
wish to screen samples upon arrival for gamma radiation using appropriate technologies.

If the presence of radioactive material is indicated by the initial screening, specific radioisotopes
may be determined by radiochemical specific procedures, using EPA 900-Series methods or
other legally defensible techniques. These procedures often involve separation  of the
radionuclide from the sample by precipitation procedures and subsequent determination by gas
flow proportional counting system or scintillation detector system for alpha and beta emitters and
an appropriate gamma detector for gamma emitters. For example, strontium-89 and strontium-
90 can be measured by EPA Method 905.0. Strontium-89 and strontium-90, are precipitated as
carbonates from the sample. Additional precipitation steps allow separation from other
radionuclides and interferences. The daughter product of strontium-90, ytrium-90 is separated
by a hydroxide precipitation step and is beta counted by a low background beta  counting system.
The combined strontium-89 and strontium-90  residue is also beta counted.  The results for each
radionuclide are determined.

Due to the unique nature of radionuclide analysis, some laboratories have developed in-house
procedures for radionuclide analysis that make use of their special skills and capabilities to
enhance the speed of analysis, especially since some EPA 900-Series methods are not rapid
methods. For example, EPA 905.0 for radioactive strontium in drinking water recommends a
two-week in-growth period for obtaining the yttrium isotope from the purified strontium.
Modification of the method results in much faster results.  Reduction in analysis time could be
accomplished by measuring the total amount of an element's radionuclide, not the isotopic
distribution. Also, for some isotopes, faster results may be obtained by simply reducing the
volume of water sample processed.

In summary, many laboratories may choose to utilize a specialized method or technique for
initial sample screening that may not be necessarily identical to those described in EPA 900-
Series methods, although these methods must be used when reporting drinking water compliance
monitoring results.
6.5  Expanded Screening using Established and/or Exploratory Techniques with
     Standardized or Non-standardized Methods
The purpose of the expanded screen is to capture chemical contaminants not picked up by the
basic screen, namely those analytes listed in Table 4-20. The expanded screen may also detect
those analytes covered by the basic screen more rapidly. It should be a sufficiently broad screen
to "go fishing" for many possible contaminants. The expanded screen can be used with a
combination of standardized or non-standardized methods.  Note that in the case of standardized
methods, no additional analytical confirmation may be required because the method used may

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itself be considered definitive if applied correctly.  In other cases, please see Section 6.2 for a
further discussion of confirmation of analytical results.

In practice, the expanded screen can be used in addition to the basic screen, because the results
of the basic screen may provide a "springboard" to guide the selection of techniques for the
expanded screen.  Alternatively, some laboratories may choose to utilize only the expanded
screen, comprised of potentially sensitive techniques, including those summarized in Table 4-4.
In the latter case, preliminary results can be cautiously used to make response decisions, but
must be followed up with confirmatory analysis since screening techniques are not necessarily
definitive or legally defensible.

Table 4-4.  Expanded Screening for Contaminants, broken out by classes  of contaminants
as found in Table 4-1.
Contaminant Type
Chemical Warfare Agents
Expanded Screening Technique
GC, GC/MS, HPLC, LC/MS, Immunoassay test kits*
Wet chemistry*
Immunoassay test kits,* GC/MS, HPLC, and LC/MS
Handheld equipment*
GC/MS with direct injection, purge & trap, and SPE/SPME,
test kits,* handheld equipment*
*See Section 4.1 for important disclaimers and information about the use of these technologies. Note that when
these technologies as being used in the expanded screen, they are being applied in the laboratory, not the field.

Given the variety of choices presented in Table 4-4, the question naturally arises about how to
select suitable methods and equipment for the expanded screen.  This section attempts to address
this in a number of ways:

    •   Although noted in Section 6.4, it is worth repeating here that information gained during
       the basic screen may help guide the selection of techniques and methods for use in an
       expanded screen.  For example, many of the techniques in the basic screen rely on
       chromatography and/or mass spectrometer, so the data should be capable of being
       evaluated for the presence of not only target analytes, but also other compounds.  In
       addition, clues about the identity of the contaminant may be provided by the mass spectra
       or chromatographic retention behavior (e.g., early eluting compounds may indicate  a
       lower boiling point, poor peak shape on a non-polar chromatography column may
       suggest  certain (polar) functional groups, etc).

    •   Combining observations from multiple basic screening techniques may be helpful.  For
       instance, if no target analyte or unknown peak is found in a Method 524.2 analysis, the
       unknown compound is likely not a volatile organic; if no peak is present in a Method
       8270D analysis, the unknown may be inorganic in nature or thermally unstable.  This
       reduces  the possibilities, although requires knowledge of the properties of potential
       contaminants.  Some of these many properties may be obvious to skilled analysts.  One
       resource to help with this is the Water Contaminant Information Tool (see Module 2),
       currently under development.
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       Many EPA standardized drinking water compliance methods are not included in Table 4-
       4, but may be used to implement the analysis summarized in Table 4-4 for expanded
       screening. This increases the number of analytes covered and, depending on the method,
       may decrease analysis time.  Some standardized methods (see Section 6.2), including
       drinking water and SW-846 methods, may be useful to apply directly in the expanded
       screen, even though they are not necessarily intended for Table 4-20 analytes. In fact, by
       their design, SW-846 methods may allow for some "quick and dirty" approaches to
       screening that might be significant time savers when faced with the short turnaround
       times associated with the initial phases of an incident.

       A discussion of the expanded screening techniques listed in Table 4-4 is provided below,
       along with some appropriate precautionary notes. Many readers will recognize some of
       these precautionary notes as being components of standardized methods.  The discussion
       below should not be  considered an exhaustive technical discussion on the subject of
       analysis of unknowns, but is intended to be an overview of those that are more widely
       used, or highly promoted.  Thus, this information is primarily intended for planners and
       some laboratories, in terms of investing in resources and techniques that may be very
       useful for expanding the screening capability to look for unknown chemicals.  Skilled
       analysts may wish to pursue other sources, such as technical books, scientific journals,
       and peer-interaction, for detailed insight and application of these techniques to specific
       technical challenges.
6.5.1   Expanded Screening for Organic Chemicals
Contaminants are often extracted from water samples to facilitate the analysis (e.g., to obtain a
suitable amount of contaminant for analysis). Regardless of the detector system employed, there
are a few widely used sample preparation techniques. Following sample preparation, a variety of
detection techniques are used to analyze the sample.  Figure 4-6 illustrates which preparation
techniques are commonly used with which detection techniques.

Sample Preparation
NOTE: Large Volume Liquid/Liquid Extraction  (LLE) generally may not be
recommended for aerosolizable samples.  This technique, although utilized in some EPA
methods, requires operation of separately funnels that may release aerosols when vented.  The
generation of these aerosols may represent a larger health hazard than other techniques, unless
laboratories take precautions, such as appropriate hoods and sampling handling techniques.
Many of the same goals of large volume liquid/liquid extraction may be accomplished through
the use of the techniques described below. The techniques below may also have other benefits,
such as reducing the consumption of sample and solvent.

a) Direct Aqueous Injection. Although a potentially powerful analytical technique, the use of
direct aqueous injection with gas chromatography may present technical difficulties in
chromatographic separation and may reduce the lifetime of the GC column and the detector.
However, some modern GC capillary columns are designed to survive the rigors of direct
aqueous injection, provided appropriate QC is applied to instrument operations and required
maintenance is performed.  For the high concentrations of contaminants that may be present
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during an emergency incident, the use of direct injection of aqueous samples with GC/MS library
matching may prove valuable, particularly for initial and rapid screening of analytes for which
laboratories do not possess the equipment utilized in a standardized method. For all but a few
analytes, analytical confirmation procedures may be necessary, and laboratories should plan
carefully, in terms of developing skills to applying this technique, verifying their GC columns
are suitable, implementing QC requirements, and preparing for additional maintenance
requirements  of both column and detector.

b) Micro Liquid-Liquid Extraction (micro-LLE). Liquid micro extraction involves the use of
small volumes of solvent (~ 2 mL) to extract analytes from a small volume (~ 40 mL) of water
(for an example, see EPA Method 551.1).  This approach is usually much quicker than the
typical LLE because of the ease of the microextraction and because no concentration/solvent
exchange is required. If the analyte is known, then a calibration standard should be analyzed
along with other requisite quality control samples to quantify the analyte. If the analyte is
unknown, then a screening approach should be taken.  The extraction may be immediately
followed by GC/MS analysis, which can provide qualitative identification from the mass
fragmentation library search. Analytical confirmation procedures may be necessary, and
laboratories should plan  carefully in terms of QC requirements  and additional maintenance
requirements  of both column and detector.  For the high, perhaps acutely toxic, concentrations of
contaminants that may be present during an emergency incident, the use of liquid-liquid
microextraction of aqueous samples with a suitable solvent, such as methylene chloride
(dichloromethane) may prove particularly valuable, particularly for initial and rapid screening
of analytes for which laboratories do not possess the equipment utilized  in a standardized
method.  Micro-LLE may not provide adequate detection limits for lower concentrations, which
may occur if the water sample represents the tail of a transient contaminant  slug.

c) Continuous Liquid-Liquid Extraction (Cont LLE). This technique, as described in EPA
Method 3520C, is applicable to the isolation and concentration of water-insoluble and slightly
soluble organics. Its use can result in excellent detection limits, like  solid-phase extraction
described below, although detection limits for specific analytes may be different.

d) Solid-Phase Extraction (SPE). Solid-phase extraction (sometimes referred to as liquid-solid
extraction) is  described in Section 6.4.2 for EPA Method 525.2 as one of the techniques for basic
screening analysis. Like micro liquid-liquid extraction, SPE extracts many  contaminants, but
can achieve larger concentration factors compared with the former technique, which may be
necessary for some analytical goals (Section 1.3).  However, many variants of the solid-phase
extraction technique are possible. For instance, instead of using a CIS adsorbent, there are many
other adsorbents available. The adsorbents have markedly different properties and may be used
to extract contaminants that are not amenable to CIS adsorbents. Different  elution solvents can
also be used as an experimental variable. As a safety note, SPE should produce few aerosols.

e) Solid-Phase Microextraction (SPME).  A relatively recent variation of solid-phase
adsorption is  solid-phase micro extraction  (SPME). Like SPE,  SPME should produce few
aerosols. SPME involves the use of a fiber coated with sorbent material, and the sorbent coated
fiber is exposed to either the aqueous sample or the headspace from the sample. The analytes
then adsorb to the coating on the fiber. After exposure to the sample, the fiber can be introduced
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into the detection system, although the technical details depend on the detector (i.e., GC or
HPLC). For instance, after exposure to the sample, the SPME fiber is inserted into the injector
of a GC, and contaminants are released to the column by thermal desorption.  Fibers are
available with several types of coating to enable extraction of analytes of different properties,
such as volatiles or semivolatiles.  Accordingly, SPME could be used for a quick screen. As
with micro-LLE, another quick screen, the detection limits may only be useful in the case of
elevated, perhaps acutely toxic, contaminant concentrations.  Lower concentrations like those
found in the tail of a transient contaminant slug, might not be detected using SPME.

f) Headspace Collection.  The headspace above an aqueous sample may be injected in a GC.
Commercial equipment, interfaced with the GC, is designed to facilitate this analysis, although
manual injections may be made.

g) Flow Injection.  In the flow injection analysis experiment, an aqueous sample or sample
extract is injected directly into an LC/MS in such a manner that it bypasses the LC column.
Thus, the analytes are not chromatographically separated, but the technique can prove useful if
high concentrations of a single analyte are present, or if sample preparation is employed that is
selective of particular analytes.

Detection Techniques
a) Multidetector GC in Screening Mode.  In Table 4-3, a multidetector GC is utilized for
specific analytes as an alternative to a mass spectrometer. However, the intent of using
multidetector GC in the analysis of unknowns is primarily as a screening tool, not necessarily to
quantify or identify, but rather to determine if the sample contains a component not normally
found in the background. Multidetector (sometimes called multispectral) GC refers to the use of
GC with a variety of detectors (there are over a dozen on the market) and then comparing the
data from all the detectors. Examples of detectors include atomic emission, electron capture,
infrared, flame ionization, nitrogen-phosphorus specific, thermal  conductivity, etc.

Various GC detectors respond to contaminants in different ways, and the evaluation of all the
data from the various detectors increases the selectivity of the analysis. For example, detectors
like flame ionization detectors tend to respond to most contaminants (but not with high
sensitivity), while electron capture detectors respond with great sensitivity (but mostly to
halogenated compounds and are less sensitive to certain other compounds). The detectors may
be used in series with one GC, or in parallel through the use of multiple GCs. In the latter case,
the peaks are correlated through the use of relative retention times, i.e., the retention time of the
peak of interest compared to a standard. Multidetector GC should be applied carefully because
of differing response of different detectors to coeluting contaminants, and
confirmatory/supplemental analysis may be necessary.  For the expanded screen, because
methods are used other than the standardized EPA methods for drinking water compliance
monitoring, it may be possible to utilize other detectors than specified in the standardized

b) Gas Chromatography with Electron Impact Ionization Mass Spectrometry  The
subsequent analysis  of contaminants extracted from water may be conducted by the use of gas
chromatography/mass spectrometry. When the mass spectrometry is performed using electron
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impact ionization, eluting peaks may show distinctive fragmentation patterns, which may be used
in identification, particularly through the use of a variety of computerized tools for library
matching to ionization patterns of known compounds.  Thus, the use of electron ionization in full
scan mode (i.e., m/z 35 to the upper scan limit of the particular instrument) may be particularly
useful when performing the analysis for unknowns using the GC/MS for analyte separation and
detection. Note that for the analysis of small molecules, it may be necessary to start the scan
below m/z 35.

It is desirable to review peaks that do not match the retention time of analytes listed in the
method. Water samples may contain hundreds or thousands of compounds, so each laboratory
must decide a threshold for examining unidentified peaks. For instance, as a starting point, the
laboratory may attempt to identify an unknown peak if it is present at >10% (height threshold) of
the internal standard using the automated programs that are available with many instrument
software packages. The threshold may need to be reduced (e.g., to 1%) or increased (e.g., to
20%) depending on the sampling location, as water samples vary in the number and intensity of
their normal background peaks.

Usually, the program performs a spectral search using a user-defined library (such as NIST,
EPA, Wiley, etc), and will report the compound with the best spectral match as the tentatively
identified compound with an estimated concentration (based on height, assuming a response
factor of 1.0).  Some of the guidelines in evaluating the spectra are:
   •  The major ions in the reference spectrum (ions greater than 10% of the most abundant
       ion) should be present in the sample spectrum.
   •  The relative intensities of the major ions should agree within +/- 20%.
   •  The base mass ion present in the reference spectrum should be present in the sample
   •  Ions present in the sample spectrum but not in the reference  spectrum should be reviewed
       for possible coelution or background contamination.

Identification of unknown compounds relies on more than the efficiency of the library search
program. The  expertise of the analyst in evaluating the mass spectra and library matches is
critical for assigning a tentative identification to the unknown. Electron impact mass
spectrometers may vary slightly by  manufacturer, vintage, and mass analyzer design. An
analyst's familiarity with the nuances of a particular instrument may greatly enhance a
laboratory's ability to confidently identify an unknown. In addition, there are a number of
options within library search software,  such as fitting algorithm, threshold parameters, result
constraints, etc.,  and a particular analyst may be more proficient with one of these options for
performing library-enhanced identification. For example, one approach may be that if the mass
spectral library "reverse fit" is greater than 800 (of a possible 1,000), the peak is reported as
identified in the report.  If the fit is 600-800, the analyst should review the library search to
determine if the identification was skewed by a coelution or high background.  If the analyst is
not able to improve upon the initial  identification (fit between 600-800), the unknown should be
listed by the class of compound assigned to that peak (e.g., "alkylated aromatic", "halogenated
aliphatic", etc.) and an approximate molecular weight.  If the report finds an unknown with a fit
below 600, and the analyst cannot improve on the identification, the peak should simply be listed
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as "unknown." The library search report should be scrutinized by an experienced GC/MS
analyst to determine how the "unknowns" should be reported.

The above procedures are based on the library match and represent only a tentative
identification.  To increase confidence in the identification, a reference standard can be
purchased, when available, to help confirm tentatively identified compounds.  Primary dilution
standards may be prepared and analyzed using the same procedure as for samples.  Comparison
of the retention time and mass spectrum of the known reference standard with the data from the
unknown may verify or negate the tentative identification.

c) High Performance Liquid Chromatography-UV Detector.  Analogous to multidetector
GC, HPLC with UV detection can be used to determine if organic compounds not amenable to
gas chromatographic procedures (e.g., nonvolatile or thermally unstable compounds) are present
in amounts greater than background.  Calibration and quality control samples should be  included
to provide an accurate analysis. Analytical confirmation may be necessary using established
techniques, such  as GC/MS. Due to technical issues with different HPLC methods, some
laboratories currently dedicate HPLC instruments to standardized methods currently being run in
the laboratory. Accordingly, it may be desirable, albeit not always practical, to dedicate an
HPLC instrument to screening activities.

Analysis for specific pesticides and other chemicals are possible, and various HPLC methods for
specific chemicals appear in the sources of methods described in Section 6.2.  Screening
procedures using HPLC may be more successful if targets are selected. For instance, a HPLC
analysis for pharmaceutical compounds of concern in water might be developed to supplement
existing methods. This method would probably involve some type of extraction (micro-LEE,
SPE, SPME, etc.) and analysis by HPLC with UV detection.  Contaminants in the extracts can be
separated with HPLC and detected through the use of a UV photodiode array detector (PDA),
which can record a UV spectrum that can be used for qualitative identification, although not
always definitely. If peaks cannot be identified from the UV spectrum, LC/MS, described
below, may be attempted under the exact same conditions (e.g., chromatography column and
elution solvent program), provided such conditions are consistent with LC/MS operation.

d) High Performance Liquid Chromatography-Mass Spectrometry (LC/MS).  Many polar
hydrophilic compounds cannot be easily extracted from an aqueous  sample. In addition, there
are contaminants of large molecular weight (e.g., biotoxins) or thermally unstable compounds
that are not amenable to GC analysis but can sometimes be analyzed by LC/MS. Direct aqueous
injection HPLC allows analysis of a sample without extraction or concentration. SPME and  SPE
(and other extraction procedures) may be utilized for compounds that can be extracted.
Identification of unknowns can be performed but there are no standardized (EPA, NIST, Wiley,
etc.) mass spectral libraries,  as in GC/MS.  Analyst interpretation can help identify possible
compound fragments  and structure. There are several ionization techniques available. Two of
the more popular ones that fall into the category of atmospheric pressure ionization (API) are
atmospheric pressure  chemical ionization (APCI), which allows the analysis of neutral analytes,
and electrospray  ionization (ESI), which allows the analysis of ionic analytes.
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Analysis of samples by LC/MS is often not a straightforward or conclusive endeavor, due to
complexities of the ionization process.  For instance, depending on the composition of the
sample, when ESI-MS is operated in the positive ion mode, it can produce [M+H]+, [M+Na]+,
and other adduct ions, which sometimes can be useful to the analyst and sometimes confounding.
For this and other reasons inherent to ESI-MS, quantification may not be always as
straightforward as with other LC detectors. Qualitative analysis of unknowns by LC/MS may be
hampered because the technique is not readily amenable to the  development of libraries, such as
those available with electron impact ionization GC/MS.  For qualitative analysis, LC/MS may be
considered best suited to providing an estimate of the molecular weight of the compound.

In summary, more than a decade after its commercialization, LC/MS is not standardized for
drinking water analysis, although it has proved extremely useful for analysis of target analytes in
other industries. Nonetheless, LC/MS can be an added tool in an expanded screen for unknown
chemicals in specific  cases, and may be useful for certain classes of pesticides, such as
carbamates.  For the analysis of specific target compounds, a skilled analyst may be able to
establish methods to analyze for pesticides and pharmaceuticals in a particular water matrix,
thereby eliminating the need for a combination of HPLC detectors and derivatization schemes.
However, these methods may not be as robust as standardized methods in terms of the analysis
of waters from various sources.  In addition, there may be many opportunities for
misinterpretation and misapplication of LC/MS data, so additional analytical confirmation steps
may be necessary to ensure confidence in and legal defensibility of the analytical results.

e) Tandem Mass Spectrometry (MS/MS).  Both GC and HPLC may be utilized in conjunction
with tandem mass spectrometry, also known as MS/MS. Different MS/MS instruments operate
under different principles to achieve similar results, but in essence can be considered to be like
two mass spectrometers connected by a collision cell. The first mass spectrometer separates
ionized molecules, which are broken apart in the collision  cell,  and the resulting fragments are
separated in the second mass spectrometer. This produces a great deal of information that can be
used to identify the original molecules, but even when used with electron impact ionization, this
technique does not necessarily produce searchable libraries. Like other advanced mass
spectrometric techniques, MS/MS is not as widely available as  MS and requires a high degree of
skill. However, it can produce unique and powerful results in the right hands.

f) High Resolution Mass Spectrometry (HR/MS). GC or HPLC, combined with a high-
resolution mass spectrometer, may provide exact mass data of an eluting  compound, allowing for
calculation of elemental composition of both molecular and fragmentation ions. This information
is useful in the identification of unknown organic compounds, especially  when the result of mass
spectral library research is not conclusive or when the standard of a tentatively identified
compound is not available. Careful quality control procedures  are required, and the technique is
not always definite, especially for unknown compounds, because many compounds may produce
fragments with the same exact masses.  Due to high capital cost and complexity of use, HR/MS
is not widely available.

g) Immunoassays. There are a large number of immunoassay tests kits  for organic chemicals,
such as pesticides and biotoxins. These may be useful for screening a sample for specific
unknowns either in the field or in the laboratory. These kits may be used for speed or if
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instrumental methods are not available in a laboratory. However, use of these kits requires that
the goals of the analysis be planned because some kits are slower than the instruments, especially
if analytical confirmation time is considered.  Also, appropriate training is necessary in the use of
these tests. Not all are the same, or easy to use. Laboratories should be aware of the kits'
reliability and levels of detection before using.

A large collection of test kits for chemicals, such as carbamate and quaternary ammonium
pesticides, and many other contaminants is summarized at
http://www.aoac.org/testkits/TKDATA2.HTM. This is by no means a complete list, and there
are a number of vendors with products not in this listing. It is important to note that most of
these test kits are not recognized by any standard setting organization. Not all of these products
have been studied in detail as to their efficacy for drinking water, which may contain interfering
and/or cross-reacting substances.  Efforts are underway to confirm the efficacy of some of these
kits for particular purposes, and as results become available, they may be reported in the Module
3, Section 3.2. In the meantime, it may be important to keep in mind the trade-offs these kits
offer in terms of sample throughput and false negatives/positive results.  In general, a positive
result from one of these test kits should be considered tentative and confirmed through a more
rigorous laboratory analysis.

Immunoassays have been developed for the analysis of urine for chemicals that may be classed
as illicit pharmaceuticals (e.g., narcotics and psychedelics). While it seems unlikely that these
substances would be used as water contaminants, there is some historical precedence for
concern.  Immunoassays represent a very sensitive approach to screening of these compounds,
and they are available from a variety of sources. Because many of these tests were designed for
urine analysis, the performance of these tests for detecting the parent compound in water should
be verified, due to the potential for cross reactivity with substances in water, which may result in
a false positive detection. Because immunoassays may be interfered with by chlorine-based
disinfectants, the residual should be quenched before use.  Established procedures also exist for
the analytical confirmation of many of these substances from urine using techniques such as
6.5.2  Expanded Screening of Inorganic Chemicals
Like the determination of organic chemicals, there are often a number of similar preparation
steps that are used in the analysis of inorganic chemicals.  These are numerous and vary with the
methodology being employed. As a starting place to select a sample preparation approach, it
may be useful to refer to relevant standardized methods.  For instance, if the goal is to look for
trace metals not listed in a particular method, it may be useful to refer to a method in which the
sample is prepared for metal analysis. This is not necessarily an exact process, and some metals
have certain characteristics that may cause them to not be amenable to a preparation technique
applicable to another. For instance, a digestion method for nickel may not be applicable for
mercury analysis. Following preparation, the samples may be analyzed by a number of

a)  ICP-AES or ICP-MS in Semiquantitative Mode. Analogous to multi-detector GC and
    HPLC with UV detection, the ICP-AES and ICP-MS methods (EPA Methods 200.7 and
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   200.8, respectively) can also be expanded to provide a broad screen approach to identifying
   unknown trace metals. Under the semi quantitative mode (SQM, referred to by various
   names depending on instrument manufacturer), the ICP-MS instrument, operated in scanning
   mode, may be capable of providing semi quantitative results for more than 60 elements
   including major atomic cations, metals,  semi-metals, rare earth elements and selected
   radionuclides (uranium and thorium) without actually including all of the elements being
   analyzed in the calibration standards. If an element is suspected, then standards may be
   obtained to perform quantitative analysis. (Note: radioactive materials should be handled by
   a specialized laboratory.) Some ICP-AES instruments can provide semiquantitative results
   for many, albeit fewer, elements than ICP-MS instruments, most of which are capable of
   SQM through the use of the correct software.  The following paragraph discusses ICP-MS
   operated in scanning mode, and SQM for appropriate ICP-AES instruments functions

   The original calculation algorithm of SQM may be applicable to all naturally occurring
   elements. Additional information may be obtained for elements that are not considered in the
   default algorithm, such as man-made radioisotopes or stable fission products with long half-
   lives, especially for isotopes in mass range between 210 and 238.  Under the SQM mode, the
   concentrations of the naturally occurring elements are calculated based upon instrument
   response factors (RF) for each element.  No internal standards are  necessarily added when
   using the SQM method. Following the external calibration procedure, a blank and a single
   calibration standard of 20-30 elements are typically used to update the RF before each
   analytical run. Increasing the number of elements in the standard generally may improve the
   accuracy of the analysis. For elements not included in the  calibration standard,  the RFs are
   updated indirectly by software interpolation from the calibrated elements. SQM identifies
   and assigns signal intensity based upon the natural abundance distributions for each isotope,
   corrects the molecular interferences by subtracting the signal of the assigned polyatomic
   species from the total signal, further corrects for polyatomic and isobaric interferences given
   in the elemental equation, and calculates the final concentration.

b) Ion Chromatography (1C). Ion chromatography forms the basis  of several EPA methods to
   determine ions of regulatory interest, such as EPA Method 300.1 for several common
   drinking water ions and disinfection byproducts. By the correct choice of operating
   conditions and ion chromatography columns, determination of many different types of ions
   have appeared in the literature, including those for some potential, albeit not high priority,
   drinking water contaminants of concern from a drinking water security perspective.

c) Wet Chemistry.  Wet chemistry forms the basis of many types of chemical test kits. The
   chemistry and detectors for test kits approved for compliance monitoring are traceable to
   EPA methods. Wet chemistry techniques, through the use of so-called "autoanalyzers," form
   the basis of many types of chemical analysis, for environmental and clinical applications.
   Manufacturers of these devices often provide full detailed methodology for defensible
   application of wet chemistry to a variety of analytes. Titrimetric methods are also available
   and can be used to analyze background water quality parameters such as alkalinity.
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d) Ion Selective Electrodes. Ion selective electrodes (ISE, also known as electrochemical
   probes) can be utilized to analyze for some background water quality parameters. A simple
   example of an ISE is the familiar pH probe for the hydrogen ion. Other ISEs for a variety of
   ions (such as ammonia, calcium, chloride, fluoride, nitrate, potassium, silver, sodium, and
   sulfide) also may be available from a variety of manufacturers and may be considered. Some
   parameters that can be monitored by ISE may be useful in characterizing the extent of
   contamination or verifying credibility of a contamination threat (see the discussion on field
   testing in Module 3).
6.5.3  Expanded Screening of Cyanides
Expanded screening of cyanides typically involves the use of sample preparation techniques and
wet chemical detection chemistries that are not used in standard EPA methods.  For instance, the
distillation step may be omitted, as it is for cyanide methods based on the Conway diffusion
technique. Note that distillation is required for determination of total cyanide concentration,
which, as discussed in Section 6.4.7, may be the most conservative approach with respect to
public health implications.  However, free cyanide concentration measured without distillation,
may still be useful, particularly in detecting high, acutely toxic concentrations

Distillation also is not used in the rapid field tests for cyanide (Section 4.1), but may be
applicable for expanded cyanide screening. As discussed in Section 3, some laboratories may
consider using these rapid field tests as safety screening tests upon receipt of the sample by the
laboratory. Note that several rapid field tests for cyanide have been evaluated as part of EPA's
Environmental Technology Verification program, including some ion selective electrodes.  The
reports, available  at http://www.epa.gov/etv/verifications/vcenterl-23.html indicate that some of
these rapid field test kits,  although acceptable for field use, may perform better when used under
controlled laboratory conditions than in the field, especially in cold weather.
6.5.4  Expanded Screening of Biotoxins
Some biotoxins have been monitored routinely for quite a while, particularly in conjunction with
naturally occurring outbreaks of biotoxins in marine environments. There are hundreds of
biotoxins from dozens of different plant and animal species.  The broad screening for
microbiological contaminants (Section 8) may capture some of the higher molecular weight
biotoxins, and analysis of some biotoxins may be supported by LRN laboratories, as indicated in
Table 4-1. In addition, the LRN currently may utilize immunoassays for biotoxin analysis of
botulism, ricin, and other biotoxins where applicable. The results of the LRN analysis should be
further communicated to any other laboratories to which chemical samples are sent.

Immunoassays. Many/all of the biotoxins listed in Table  1-1 have commercially available
immunoassay kits. A large collection of test kits is summarized at
http://www.aoac.org/testkits/TKDATA2.HTM. This is by no means a complete list, and there
are a number of vendors with products not in this listing. It is important to note that most of
these test kits are not recognized by any standard setting organization,  and the applicability of
these products to disinfected drinking water, which may contain interfering and/or cross-reacting
substances, is not well studied. Efforts are underway to confirm the efficacy of some of these
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kits for particular purposes, and as results become available, they may be reported in the
Appendix to Module 3 that lists field test equipment. In the meantime, it may be important to
keep in mind the trade-offs these kits offer in terms of sample throughput and false negative/false
positive results.  In general, a positive result from one of these test kits should be considered
tentative and confirmed through a more rigorous laboratory analysis.

A key part of laboratory analytical screening for a biotoxin is the ability to confirm its tentative
identification (e.g., via an immunoassay test kit).  Confirmatory analyses are discussed in more
detail below, and usually involve GC/MS, LC, or LC/MS. The IOC Manual on Harmful Marine
Microalgae, available at http://unesdoc.unesco.org/images/0012/001220/122021 eo.pdf contains
many examples of these types of analyses, chiefly intended for analysis of algal biotoxins. One
type of assay that has been widely used for the determination of biotoxins in seafoods over the
past 60 years is the mouse bioassay. The applicability of this technique to water samples is not
well investigated, and most laboratories do not have facilities for the care of laboratory animals.
In addition, immunoassay techniques are less sensitive than instrumental analysis techniques.

The biotoxins may be considered as organic chemicals, and the same types of sample preparation
and instrumental analysis techniques may be applicable, depending on the molecular weight  of
the biotoxin. Low molecular weight toxins may be treated much like any organic chemical
described in Section 6.5, and may be analyzed by the same type of analytical techniques (e.g.,
GC/MS) as described therein. Because biotoxins tend to be very water soluble, liquid
chromatography techniques have been used to determine biotoxins in water. When LC/MS is
used, the same precautions may be necessary as those for other organic chemicals (see Section
6.5.1).  The analysis of biotoxins is one area where LC/MS has proved particularly valuable,
especially if the molecular weight of the biotoxin precludes its analysis by GC/MS.  Again, the
skill of the analyst is critical in obtaining meaningful results for LC/MS analysis of biotoxins.
6.5.5  Expanded Screening of Radionuclides
Radiological analysis, as noted above, should be performed only by licensed, specialty
laboratories, and the need for such analysis should be indicated by the field screening equipment
for alpha, beta, and gamma emitters.  As discussed in Module 3, the site characterization will
determine the appropriate laboratory to receive radioactive samples (e.g., high levels of radiation
would indicate a radiation hazard, and only the appropriate radiation laboratory would receive
the sample). If the laboratory should wish to screen samples before accepting them or analyzing
them, then inspection of samples for alpha, beta, and gamma radioactivity using probes for these
emitters may be prudent (e.g., the devices used by the first responder/sample collector as
described in section 3.1.4).  Again, a positive test from the screening devices should be sent to
specialty laboratories for confirmatory analysis.

The basic screen discussed in Section 6.4.8 is rather comprehensive because it requires
identification of the specific radionuclide if indicated by the screens for gross alpha, beta, and
gamma radiation. Therefore, the expanded screen is designed to capture radionuclides that do
not fall into the energy range of the gross radionuclide screen for gross alpha and beta.
Fortunately, these radionuclides have specific EPA 900-Series methods designed for their
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analysis, and radionuclide laboratories may be familiar with these few radionuclides and have
other reliable methods at their disposal for their analysis.

Two other techniques that may be particularly useful for radionuclide analysis are gamma
spectroscopy, which can directly identify the gamma emitting radionuclide and inductively
coupled plasma mass spectrometry (ICP-MS). Principal considerations in the use of both of
these techniques include detection limits and availability of instrumentation. Often, these
considerations are based on the particular radionuclide involved. To better understand and deal
with the needs and roles of the wide variety of analytical radiochemistry techniques at the
disposal of radionuclide laboratories, the Multi-Agency Radiological Laboratory Analytical
Protocols (MARLAP) Manual has been developed by the Environmental Protection Agency, the
Department of Energy, the Nuclear Regulatory Commission, the Department of Defense, the
National Institute of Standards and Technology, along with some states
(http://www.epa.gov/radiation/marlap/).  This effort is but one component in the EPA's
Radiological Emergency Response Plan (http ://www.epa.gov/radiation/rert/docs/rerp-1 -OO.pdf)
in support of EPA's responsibilities for protecting the environment and in support of the Federal
Radiological Emergency Response Plan
6.5.6  Expanded Screening of Chemical Weapons
As discussed in Section 2.1.4, the term chemical weapons refers to the substances, such as those
shown in Table 1.1, that appear on Schedule 1 of the Chemical Weapons Convention (CWC,
http://www.cwc.gov/Regulations/cfr-15/part-712-sl_html).  There are other substances, such as
chemical weapon precursors, that are monitored by the CWC under Schedules 2 or 3, which also
may be present in water at very low concentrations (typically less than 10 |lg/L) due to industrial
pollution or the formation of disinfection byproducts. Table 4-18 in the Appendix (Section 10)
lists the Scheduled chemicals. Chemicals on Schedules 2 or 3 have fewer restrictions compared
with Schedule 1, since many have legitimate industrial applications. Thus, environmental
laboratories could potentially analyze for many Schedule 2 or 3 chemicals. This section focuses
on the analysis of Schedule  1 chemicals, which are most restricted.

The Schedule 1 agents used as chemical weapons are extremely hazardous to handle and most
environmental chemistry laboratories do not have the facilities or the procedures in place to
handle these agents. In addition, most of the agents are not available commercially to prepare
analytical standards for quantification. The chemical weapons agents will need to be analyzed
by special chemical weapons laboratories for confirmatory analysis. However, in the unlikely
case that an environmental chemistry laboratory receives a sample containing a chemical
weapon, screening techniques can be used by environmental chemistry laboratories to identify
the presence of the agents in water.

The best analytical approach may be to utilize the preparatory procedures (direct injection,
micro-LLE, SPE, and/or SPME) as discussed above, followed by GC/MS for identification. This
may only be able to determine the presence, not concentration, of the agent because an  analytical
standard would not be available. However, the standard electron impact mass spectral libraries
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frequently contain mass spectra of these compounds and can be used for tentative identification.
As an aid to increasing confidence in chemical warfare agents' GC/MS library matches, the
National Institute of Standards and Technology has developed the Automated Mass Spectral
Deconvolution and Identification System (AMDIS), http://chemdata.nist.gov/mass-spc/amdis/.

In the unlikely case CW agents are present, the expanded screen for organic chemicals may be
procedurally designed to reduce risk, namely through reduction of aerosols. As with any organic
chemical, an additional way to reduce risk would be through sample dilution.  The laboratory
may first start with the most dilute sample (1/1,000) and if nothing is detected may proceed to
analyze the next dilution (1/100), followed by the 1/10 dilution, and lastly the undiluted sample.
If the laboratory proceeds through the undiluted sample and nothing is detected, the sample may
be deemed non-detect for the chemical weapons that would be captured by the screen. If the
chemical weapons agents are identified in the screen, proper notifications should be made to law
enforcement to gain access to laboratory resources that can confirm  the presence of the chemical
weapons agent.
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7   Examples of the Analytical Approach to Site-Specific Situations for
    Chemical Contaminants

Section 6 describes an analytical approach based on chemical contaminants considered important
from a national perspective. As noted above, local authorities may wish to develop their own
analytical approach based on their perceived needs and concerns. Here are some brief examples
of analytical approaches based on the concept of basic and expanded screening. The first five
(Section 7.1) are derived from the needs of specific, hypothetical utilities, and the final three
(Section 7.2) are geared toward laboratories that serve a wider base of clients.

The overriding principle in these examples is the flexibility that laboratories have in developing
and updating an analytical plan for the analysis of unknowns in water. Utility laboratories may
have the greatest level of flexibility with respect to the comprehensiveness of their screen if they
have made arrangements with other labs to perform more comprehensive screening as necessary.
For example, utility laboratories may choose to perform some level of basic screening that may
be applied in the case of a 'possible' threat; however, analysis may need to be performed at
another laboratory in response to a  threat deemed 'credible'.  On the other hand, laboratories
that serve a wider customer base should have a more comprehensive and robust screening
procedure to cover the range of potential scenarios that might be encountered in working with
various utilities.
7.1  Examples for Utility Laboratories
These five examples are targeted at utility laboratories that chose to develop an analytical
approach to support analysis of their own emergency water samples, and make arrangements to
engage other laboratories with broader capabilities when necessary. This is to say, it is part of
upfront planning for a utility to decide when they will handle samples in-house and when they
will send them to external laboratories.  In many of these examples, the utility laboratories often
take a "springboard" approach to screening, using the results of the basic screen to make
decisions in the expanded screen.

Example #1: Based on the results of a vulnerability assessment, a local water utility has
concluded that their consumers are at only a very small risk from water contamination incidents,
and so do not want to invest much of their limited resources in overly detailed analytical
approach.  They possess a purge-and-trap-GC instrument with conventional photoionization and
electrolytic conductivity detectors in series,  and are certified to perform analysis of Method
502.2 analytes.  They possess a GC/MS for  another purpose, so they choose to expand their
laboratories capabilities by making a small purchase of a solid-phase extraction manifold and
supplies suitable for Method 525.2 analytes. They allow their laboratory staff the time to
become proficient with Method 525.2 to ultimately obtain  certification by their state. In the
meantime, they plan on using the technique  in the expanded screen. They decide to  exclude
carbamate pesticides and quaternary ammonium compounds from  their analytical  approach
because they are not available anywhere nearby, and the utility does not believe that they will be
important because there are opportunity contaminants available locally. One of these
opportunity contaminants is glyphosate, which, although not very toxic to humans, is widely
used in the area. They search NEMI, or another source such as those listed in Table 4-2, and find
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a suitable method.  They do not possess any capability for trace metal analysis, so they contract
this out to a third party who performs Method 200.7. In looking at the analyte list for Method
200.7, the laboratory sees that mercury can be analyzed by Method 200.7 and seeks data from
the contracted third party that their instrument provides sufficient detection limits for arsenic and
mercury. The utility laboratory realizes Method 200.7 most likely will determine many
organomercury compounds (as total mercury), so they decide that the benefit of enhancing their
mercury screening capabilities through the addition of Method 245.2 to their basic screen is not
worth the expense. In their locality, the first responders to contamination incidents possess, and
are trained in, the use of portable cyanide detection systems and radiation detectors.  They buy a
low-cost gamma detector to screen samples in the laboratory as a safety precaution. Thus,
instead of Table 4-3, their basic analysis may be summarized in Table 4-5.  Clearly, this is not as
rigorous as Table 4-3, but does meet many of the same needs.

During an incident, if the threat evaluation and site characterization indicated that greater
analytical capability is required for expanded screening or confirmatory analysis, they plan to
rely on state resources, although there is a four-hour delay in getting the samples to the state
laboratories.  If the water utility emergency response manager (or the designated incident
commander) must have results faster, they plan to perform direct aqueous injection into their
GC/MS with the hope of getting a successful GC/MS library match.  They also consider
performing a micro-liquid liquid extraction using methylene chloride for the same purpose.
However, due to the resulting additional instrument maintenance requirements, which may make
the instrument unavailable for its intended purpose, they do not want to do this routinely.

Table 4-5. Basic Screen for Chemical Analysis for Example #1
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic)
Trace metals (inorganic)
Local contaminant (Glyphosate)
Analytical Technique
Purge-and-trap PID/ELCD
Solid-phase extraction GC/MS
Contracted out
By first responders
By first responders
EPA Method
Example #2: A utility laboratory has a great number of legally defensible protocols (some of
which are EPA methods) already in place, except for radionuclides, which are handled by a
separate department. They examine the analytes in the methods in Table 4-3, and determine to
the best of their ability and interest that their protocols already cover all the contaminants about
which they are concerned.  Thus, their version of an analytical approach for chemicals may
appear as shown in Table 4-6.
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Table 4-6.  Basic Screen for Chemical Analysis for Example #2
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic)
Carbamate pesticides (organic)
Quaternary nitrogen compounds (organic)
Trace metals (inorganic)
Total mercury (including organomercury
Analytical Technique
Purge-and-trap GC/MS
Solid-phase extraction GC/MS
Derivatization GC/MS
Cold vapor AA
Wet chemistry
First responders
EPA Method
In-house protocol
In-house protocol
In-house protocol
In-house protocol
In-house protocol
In-house protocol
In-house protocol
In-house protocol
In addition, the laboratory possesses a significant capability in terms of instrumentation and
analytical expertise to perform the expanded screening analysis, such as interpreting electron
impact mass spectra and performing immunoassays. Thus, Table 4-6 is consistent with their
needs and may comprise their analytical approach.

Example #3: A water utility decides its water security concerns are reflected in the approach
presented in Section 6.  The utility has access to laboratories that are capable of performing the
methods in Table 4-3, except radionuclide analysis, which is handled by emergency responders
in accordance with state policy. However, they do not have access to expanded screening
techniques, and choose not to include in-house expanded screening, since their local emergency
operations policy does not allow time for detailed expanded screening.  Thus, decisions would
typically be based on the results from the basic analytical screen. However, the utility has made
arrangements with a commercial laboratory to perform some expanded screening if deemed
necessary based on the circumstances of the incident.

Table 4-7.  Basic Screen for Chemical Analysis for Example #3
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic)
Carbamate pesticides (organic)
Quaternary nitrogen compounds (organic)
Trace metals (inorganic)
Total mercury (including organomercury
Analytical Technique
Purge-and-trap GC/MS
Solid-phase extraction GC/MS
HPLC - fluorescence detection
Graphite furnace AA
Cold vapor AA
Wet chemistry
Emergency responders
EPA Method
245.1 with persulfate

Example #4: A water utility only has capability for basic water quality parameters, such as pH,
turbidity, and chlorine residual. The utility has always sent samples to the state laboratory for
routine analysis and does not have resources to do differently, even in the case of an emergency.
They do, however, make plans for how to most efficiently deliver the samples to the state
laboratory, and recruit employees from other city and county offices to help implement the plan
if the regular staff of two persons is not available.  Note that the techniques used by the state
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laboratory (shown in Table 4-8) are the same as in Table 4-3. However, from the utility's
perspective, the state laboratory governs the selection of the techniques.

Table 4-8.  Basic Screen for Chemical Analysis for Example #4
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic)
Carbamate pesticides (organic)
Quaternary nitrogen compounds (organic)
Trace metals (inorganic)
Analytical Technique
Purge-and-trap GC/MS
Solid-phase extraction GC/MS
HPLC - fluorescence detection
Wet chemistry
Gross alpha, gross beta,
gross gamma radiation
EPA Method
technique referred by
state lab
Example #5: A utility laboratory has a purge-and-trap GC/MS, a regular GC/MS, and an ICP-
MS. Their basic screen is represented in Table 4-9.

Table 4-9. Basic Screen for Chemical Analysis for Example #5
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic)
Trace metals (inorganic)
Analytical Technique
Purge-and-trap GC/MS
Solid-phase extraction GC/MS
EPA Method
While this leaves some gaps in their analytical coverage, they plan to address these deficiencies
through an expanded screen. They acquired immunoassay test kits that have undergone some
level of validation, such as ETV (http ://www. epa. gov/etv).  For these and other kits, the
laboratory understands the limitations of these test kits (see Section 6.5.1 and 6.5.4) and has
arranged analytical confirmation of the analytes with state laboratories should the need arise.
The laboratory also has an agreement with a local university that has a mass spectrometry facility
including an LC/MS.  The utility laboratory takes steps to ensure that the university
laboratory/staff will be available in the case of an emergency and all chain-of-custody rules and
legal defensibility issues have been met.  The utility also has made arrangements to contract out
the confirmatory analysis, if necessary.  Although the utility recognizes there are potential
problems with this arrangement, it believes this plan meets its needs.
7.2   Examples for Laboratories with a Wide Client Base
The concept of basic screening takes on a different dimension for laboratories that serve a wide
client base because utility laboratories are most likely faced with 'possible' incidents.
Accordingly, they may feel reasonably confident in the comprehensiveness of the screening
procedures, illustrated in examples #l-#5. On the other hand, laboratories that serve a wide
client base have a larger opportunity to receive a sample from a 'credible' incident. There are
two reasons for this.  First, these laboratories serve more clients, so on a strictly mathematical
basis, they have a greater chance.  Second, utility laboratories in 'credible' situations may be
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more likely to refer samples to another laboratory, which may have greater capability to apply a
more focused analytical approach in response to a specific incident (as discussed in Section 5).

Accordingly, laboratories that choose to perform analysis of emergency water samples and serve
a broader client base, such as Federal, State, and commercial labs, may need to adopt a more
comprehensive approach such that they maintain flexibility to provide analytical support in a
variety of situations.  However, as the following three examples illustrate, this goal can be met in
a variety of ways.

The first two examples represent extreme cases of laboratories preparing to respond to a
'possible' and/or 'credible' incident. The first example represents a laboratory that does not
define a basic screen and will perform analyses as part of a comprehensive expanded screening
program. The second example depicts a laboratory that attempts to be comprehensive by
including a very large number of standard methods in their basic screen.  The third example
blends the first two examples and adopts a screening approach that aligns closely with the
complete "Basic Screen" (Table 4-3) and has some capability for the "Expanded Screen" (Table
4-4), as well.

Example #6. Utilities in a county are all serviced by the same central laboratory. However, the
needs of the utilities are somewhat different, so after a meeting between all utility and laboratory
representatives, it is agreed that the plan is to perform no basic screens. The decision was based
on response times for utilities, mandated by the locality, being too short for the basic screen. The
laboratory will instead perform the expanded screen using exploratory techniques that have short
response time, such as those discussed in Section 6.5 (Table 4-4).  The laboratory has skilled
analysts and modern equipment and is confident of its capability.  The laboratory also is capable
of performing confirmatory techniques for some contaminants, if necessary. The planners
realize that this approach may not meet all desired QC goals for every contaminant, but are
prepared to live with the consequences of basing decisions on this kind of data.

Table 4-10. Basic Screen for Chemical Analysis for Example #6
Chemical (general class)
Analytical Technique
EPA Method
Example #7. A state laboratory that supports a large number of utilities. The laboratory
performs many EPA drinking water and SW-846 methods routinely, and it wants to include as
many techniques as possible in the basic screen.  It chooses to do this since the needs of water
systems it serves vary greatly, and most are small and understaffed to the point that the utilities
generally rely on the state for all analyses and analytical decisions. The laboratory also realizes
that only a broad screen will be sufficient to cover the majority of potential emergency scenarios
that its utility clients may face. Also, the laboratory wants to exercise "due diligence" up to the
level of a 'credible' threat, as defined by the threat evaluation , and it realizes that more analytes
are captured by these methods than are in the basic screen in Table 4-3, and that some of the
methods are more sensitive for particular analytes. In all, the laboratory feels that the inclusion
of all these methods would be valuable for their clients.
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Note that the laboratory chooses preparation methods for the SW-846 methods to make them
compatible with the drinking water methods, so that it does not have to prepare the sample twice
in many cases.  The laboratory feels that its basic screen best meets the needs of its clients. It
does perform some expanded screening to try to identify unknown chromatographic peaks in its
analysis and through combining all the analytical results from the various techniques.

Table 4-11. Basic Screen for Chemical Analysis for Example #7
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic)
Nitrogen and phosphorus-containing
pesticides (organic)
Chlorinated pesticides, herbicides, and
organohalides (organic)
Chlorinated acids (organic)
Phenols (organic)
Carbamate pesticides (organic)
Glyphosate (organic)
Quaternary nitrogen compounds (organic)
Chlorination disinfection byproducts,
chlorinated solvents, and halogenated
pesticides/herbicides (organic)
Water soluble alcohols/non-chlorinated
organics (organic)
Organochlorine pesticides (organic)
Organophosphorus compounds (organic)
Chlorinated herbicides (organic)
Trace metals (inorganic)
Total mercury (including organomercury
Analytical Technique
Purge-and-trap GC/MS
Solid-phase extraction GC/MS
solid-phase extraction GC/MS
HPLC - fluorescence detection
GC/FID with direct aqueous injection
GC/MS after methylation or
ICP-MS in scanning mode
Cold vapor AA
Wet chemistry
Immunoassays with confirmatory
Gross alpha, gross beta, gross gamma
EPA Method
245.2 with persulfate

technique referred by lab
Example #8: A laboratory serves an area that has several drinking water treatment plants
located downstream from an agricultural area, an industrial area, and/or a nuclear power plant.
In addition, there are geological formations that contribute to high inorganic contaminant levels.
Fortunately, the laboratory is very well equipped and staffed, with strong capabilities and
experience in monitoring all the classes of contaminants in Table 4-3. In addition, the laboratory
expands the analyte list (see Table 4-20) for these methods to include as many analytes as
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Table 4-12. Basic Screen for Chemical Analysis for Example #8
Chemical (general class)
Volatiles (organic)
Semivolatiles (organic)
Carbamate pesticides (organic)
Quaternary nitrogen compounds (organic)
Trace metals (inorganic)
Total mercury (including organomercury
Analytical Technique
Purge-and-trap GC/MS
Solid-phase extraction GC/MS
HPLC - fluorescence detection
Cold vapor AA
Wet chemistry
Gross alpha, gross beta, gross gamma
EPA Method
technique preferred by lab
Due to sources of potential contaminants other than intentional contamination, the laboratory
also maintains careful records of ranges of contaminants it normally encounters, so that during
an emergency incident, it does not confuse background levels of contaminants with intentionally
introduced ones.

For expanded screening, the laboratory utilizes its existing instrumentation with the techniques
discussed in Section 6.5.  The laboratory is particularly interested in developing an HPLC screen
for pharmaceuticals (which it was already interested in due to potential regulatory issues), and
would like to explore micro-LLE and SPME for this purpose. Therefore, the laboratory acquires
the required equipment and supplies, and encourages its staff to investigate these techniques.
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8   Analytical Approach for Biological Contaminants

8.1  Overview of Contaminant Issues

8.1.1   Types of Biological Contaminants Covered by the Analytical Approach
Two broad classes of pathogens may be encountered in a contaminated water sample:  1)
traditional waterborne pathogens such as enteric bacteria, viruses and protozoa; and 2) exotic and
select agents that may be suitable for a water route of transmission.  Table 4-13 lists some of
these pathogens. This section is intended as a guide for selecting analytical approaches for
samples suspected of containing known and unknown microbial contaminants. Specific
methodologies will be addressed in a laboratory analysis guide for biological contaminants
(under  development).
Table 4-13. General Classes of Pathogens, Specific Organisms, and Select Agent Status
Pathogen general class
Bacteria (non-spore forming)
Bacteria (spore forming)
Bacteria (Rickettsia)
Brucella spp.
Burkholderia pseudomallerei
Campy lob acter spp.
E. coli0157:H7
Francisella tularensis
Salmonella spp.
Shigella spp.
Vibrio cholerae
Yersinia pestis
Bacillus anthracis
Clostridium botulinum A
Coxiella burnetti
Cryptosporidium parvum
Entamoeba histolytica
Giardia intestinalis
Toxoplasma gondii
Hepatitis A
Hepatitis E
Select Agent*


* See http://www.cdc.gov/od/sap/docs/salist.pdf

8.1.2   Selection of Appropriate Analytical Approach for Contaminant Analysis
The analytical approach for these biological contaminants can be divided into two distinct steps,
sample collection and sample analysis. All information prior to and during the threat evaluation
(Module 2) needs to be carefully considered to assess the microbial contaminant threat and to
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apply a relevant sample collection and sample analysis procedure. Different sample collection
and analysis approaches are described below.

The overall approach for sample collection and analysis for microbial contaminants is based on
the target contaminant. When the target contaminant is known, then established and validated
technologies for sample collection and methods for analysis are utilized. When the target
contaminant is unknown or when the contaminant is known but established and validated
procedures for collection are not available, then an ultrafiltration device is used for sample
collection and exploratory methods of analysis are utilized.

8.1.3  Microbial Sample Collection Considerations
Figure 4-8 illustrates the overall approach for sample collection for microbial contaminants.
This approach utilizes established and validated sample collection techniques when the target
contaminant has been tentatively identified based on available information from the site
characterization report.  Examples of situations in which tentative identification might occur
include: a specific contaminant named in a threat; physical evidence at the  site  pointing to a
specific contaminant; and clinical evidence of the identity of the disease-causing contaminant. In
the case where the contaminant is unknown,  sample collection is performed through the use of an
ultrafiltration sampler (see Section 8.3).
                                                       Perform Unknown
Perform Unknown
Figure 4-8. Analytical Approach for the Collection of Microbial Contaminants
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The ultrafiltration approach may also be desirable for a number of reasons. First, the sample
may contain a mixture of microbial contaminants.  Second, due to the low infectious dose of
most waterborne pathogens, a sample of 100 liters of finished water may need to be concentrated
to obtain suitable detection limits. Third, sample concentration technology for viruses and
protozoa require separate field equipment and procedures and are practical only if the microbial
contaminant is suspected or identified as one amenable for concentration by each of these
specific technologies. Thus, in a contamination threat or incident, it may be necessary to utilize
a more general sample concentration procedure based on ultrafiltration that targets a wider range
of microorganisms.
8.1.4  Microbial Processing and Analysis Considerations
Making a determination as to whether the microbial contaminant has been tentatively identified
is important since it will determine the type of laboratory that can do the processing and analysis.
Non-select agents or BSL levels 1 and 2 contaminants that are regarded as waterborne
pathogens, including the enteric bacteria, viruses and protozoa, can be sent to an environmental
laboratory. If the contaminant is unknown or is a select agent, the sample is to be shipped to a
specialty laboratory (Figure 4-9).
                             Determine Concentration Method
                                 Needed (Figure 4-8)
Figure 4-9. Approach for the Processing and Analysis of Microbial Contaminant Groups
*The specialty laboratory includes the Laboratory Response Network Laboratories among other specialty labs.
8.2   Established Techniques for Sample Collection of Known Waterborne
If a microbial contaminant has been tentatively identified, the available and established
techniques may be the more direct approach for sample collection and analysis.  The advantage
of these techniques is that a broader base of expertise and more analytical laboratories are
available to water utilities than is available for select agents and for exploratory techniques.
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Established and validated methods for sample collection and analysis of microbial contaminants
in water are limited to a few microorganisms, mainly some enteric bacteria, viruses and
protozoa, and a few other organisms with a known waterborne transmission route, listed in Table
4-14. If the contaminant is not known or the available site investigation and intelligence
information is not considered sufficiently reliable for the use of an established method, the
procedure for microbial unknowns (Section 8.4) is to be used.

Table 4-14.  Known Waterborne Pathogens with Established Techniques for Sample
Collection and Analysis
(general class)
Campylobacter spp.
E. coli0157:H7
Salmonella spp.
Shigella spp.
Vibrio cholerae
Cryptosporidium parvum
Giardia intestinalis
Hepatitis A
Analytical Technique
Culture in selective media
Mammalian cell culture
SM 9260 G
SM 9260 F
SM 9260 B
SM 9260 E
SM 9260 H
EPA 1622/23
EPA 1623
EPA ICR manual
1. SM refers to Standard Methods for the Examination of Water and Wastewater (Clesceri et. a.l., 1999).  The EPA
methods may be found at http://www.epa.gov/nerlcwww/
2. Immunomagnetic separation (IMS) and immunofluorescence assay (FA) microscopy.
8.2.1  Bacteria Collection with Established Techniques
The established sample collection procedures for bacteria are essentially grab samples that are
later processed by membrane filtration of typically 100 milliliters to two liters. A four liter grab
sample will allow for analysis for different bacteria by plating multiple membrane filters on
separate selective or enrichment media. Special shipping regulations apply to samples known to
contain pathogens (see Module 3, Section 6 for requirements for shipment of infectious
materials, http://www.bt.cdc.gov/labissues/PackagingInfo.pdf).  If select agents are not known or
are not suspected to be in the water, then the sample is considered an environmental sample, and
volumes of four liters or less can be collected and shipped using standard sampling containers.

8.2.2  Virus Collection with Established Techniques
The established sample collection procedures for viruses involve concentration on positively
charged filters (ICR Microbial Laboratory Manual, EPA/600/R-95/178, April 1996,
http://www.epa.gov/nerlcwww/). This method is reasonably effective for concentration of
enteric viruses from large volumes  of water.  Samples in excess of 100 liters can be easily
concentrated by this method.  The ICR method has been used to concentrate  1,200 liters of
finished water.  The processed filters can be shipped to the laboratory, or viruses adsorbed to the
filter can be eluted in the field and shipped as a one-liter concentrate to a laboratory for further
processing by conventional reconcentration procedures.
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8.2.3  Protozoa Collection with Established Techniques
The established procedure for protozoa sampling in water consists of obtaining a 10-liter grab
sample or field concentration by filtration (Method 1623: Cryptosporidium and Giardia in Water
by Filtration by IMS/FA, EPA-821-R-99-006, April 1999, http://www.epa.gov/nerlcwww/).  The
ten-liter grab sample or the filter is shipped to the laboratory for further processing.
8.3  Established Techniques for Analysis of Known Waterborne Contaminants
Established analytical techniques are based on culture assays in selective media for bacteria,
selected cell lines for viruses and IF A with antibodies for protozoa identification (Table 4-14).
Culture based techniques are not available for some contaminants and these techniques have long
turn-around times for analysis.  Thus, it may be necessary to utilize exploratory methods (Section
8.4.3) due to time restraints or the absence of an established culture method for a particular
pathogen. Exploratory methods are primarily molecular-based, and involve PCR and probe
hybridization as a presumptive test, followed by sequence analysis to confirm.  If necessary,
samples could be simultaneously  analyzed by both rapid exploratory methods and established
8.3.1  Bacteriological Analysis with Established Techniques
Sample collection for laboratory analysis of pathogenic bacteria in water samples consists of
processing a grab sample by membrane filtration and transferring the membrane onto selective or
enrichment media for presumptive identification (Figure 4-10). The enteric bacteria and other
non-select pathogenic bacteria can be confirmed by conventional methods based on biochemical
profiles, serological identification, or other culture based methods. The vast majority of enteric
bacteria can be analyzed with BSL-2 containment level; thus an environmental laboratory with
that containment level could proceed with confirmatory identification of non-select organisms.

If the presumptive tests indicate the possible presence of a select agent, the sample and the
isolated culture must be referred to a specialty laboratory (Figure 4-10).  Federal regulations
prohibit the handling and maintenance of select agents unless the laboratory has registered with
the CDC under the requirements of the Select Agent Rule (see Section 2.2).
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                               Identification as
                                 lect Agent?
 Select Agents
to Specialty Lab
                              Perform Established
                               Analysis on Non-
                                select Agents

Figure 4-10. Bacteriological Screening with Established Techniques

8.3.2  Virological Analysis with Established Techniques
Established techniques for virological analysis consist of plating the sample concentrate on cell
lines receptive to the target viruses.  The target viruses anticipated in a water sample are the
enteric viruses. There are cell lines receptive to a number of them (see Table 4-13).  It may be
necessary to inoculate a sample on multiple cell lines to cover the range of possible virus targets.
A presumptive positive result of a cell culture test is the production of cytopathic effects on the
cell monolayer as observed by light microscopy.  Established virus confirmation and
identification techniques consist of serological neutralization with specific antibodies against the
various viruses or by means of pools of antisera with respective identification tables.  If a
presumptive identification suggests the presence of a select virus agent, the sample, culture and
other processed sample materials must be referred to a specialty laboratory (Figure 4-11).

If an established technique is not available for a specific virus or if the virus is known not to
grow in cell culture, exploratory PCR-based techniques may be the more appropriate  approach
for presumptive identification.  Presumptive identification is based on PCR amplification  and
probing.  Analytical confirmation is conducted by sequence analysis of the amplified  material.
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                                On-site Filtration
                                100-1000 Liters
                                  Elute and
                                Identification as
                                  elect Agent?
 Select Agents
to Specialty Lab
                               Perform Established
                                Analysis on Non-
                                 select Agents

Figure 4-11.  Virological Analysis with Established Techniques

8.3.3  Parasitological Analysis with Established Techniques
Established sample collection techniques for protozoa in water consist of obtaining a grab
sample of 10 liters or alternatively, performing filtration in the field (EPA Method 1623,
http://www.epa.gov/nerlcwww/). The grab sample or the filter is sent to an environmental
laboratory for processing. In the laboratory, protozoa retained by the filter are eluted,
concentrated by centrifugation and purified by immunomagnetic separation (IMS).  Giardia
cysts and Cryptosporidium oocysts are identified and counted by the indirect fluorescent assay
with an epifluorescence (or UV) microscope (Figure 4-12).

Exploratory techniques such as PCR can be readily applied to cysts and oocysts purified by the
immunomagnetic separation step of Method 1623. In addition, the infectivity of
Cryptosporidium oocysts can also be determined by cell culture infectivity after IMS
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                                        Grab 10 Liters
                                       or Field Filtration
                                       Elute, Centrifuge
                                         and IMS
                                       I FA with Specific
Figure 4-12. Parasitological Analysis with Established Techniques
8.4  Method for Sample Collection, Field Processing, and Laboratory Analysis for
     Unknown Microbial Contaminants
Sample collection, processing, and analysis of an unknown microbial contaminant are inherently
linked because the procedure relies on the use of an ultrafiltration device in the field (see Module
3).  Together, the collection, processing, and analysis may be considered to constitute a method
for unknown microbial contaminants, and the individual parts are discussed below. This method,
including a suitable ultrafiltration device, is currently under development.

8.4.1  Sample Collection and Concentration for Unknown Microbials
Ultrafiltration  is a size exclusion process, and particles larger than the molecular weight cut-off
(MWCO) of the membrane, are concentrated in the retentate and separated from infiltrate.
Ultrafiltration  can concentrate viruses, bacteria, spores or parasites as long as the organisms are
larger than the MWCO of the membrane selected. Thus, the method is suitable for sampling
water with an unknown biological contaminant.  Also, ultrafiltration of water samples can be
used to concentrate some biotoxins if the MWCO of the selected membrane is sufficiently small.

The overall procedure, illustrated in Figure 4-13, consists of concentrating large (100 liters or
more) volumes of water by cross-flow disposable hollow fiber ultrafiltration cartridges, and
subsequently recovering pathogens and other concentrated microorganism and particles in the
filter retentate. The recovered retentate is referred to as the field sample concentrate. The field
sample concentrate will be separated into three aliquots. Ultrafiltration of 100 liters or more of
finished (e.g., tap) water will result in a retentate volume of approximately 250 ml. A small
aliquot (l/20th of the field sample concentrate) can be used for field screening (Section 8.4.2).
Approximately one half of the field sample concentrate can  be used for presumptive PCR testing
(Section 8.4.3). The remainder can be used for confirmatory culture techniques (Section 8.4.4).
The reason for dividing the field sample concentrate is that some of the reagents for molecular
analysis that may be added in the field will essentially inactivate any microbes present in the
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The basic elements of an ultrafiltration field concentration apparatus (Figure 4-14) consist of an
input reservoir for sample collection, a peristaltic pump, a cross-flow hollow fiber membrane
cartridge, a retentate reservoir and a filtrate reservoir.  Operating the unit in cross-flow mode is
preferable because "caking" or fouling of membranes is reduced. Non-reactive membranes are
preferable, such as polysulfone or low protein binding membranes.

Sample filtration is conducted by recirculating water (necessary to maintain cross-flow
conditions) with a 5-10 PSI differential between the input and retentate pressure. The pressure
differential forces water through the hollow fiber membrane which retains particles (including
microbes) larger than the membrane pores in an increasingly concentrated liquid retentate
volume. The water containing particles that passes through the filter is known as filtrate.  The
volume of the retentate is reduced to approximately 250 ml by recirculating the concentrated
sample through the smaller retentate loop for capture in the retentate reservoir.  The retentate
reservoir vessel can be used for sample shipping if necessary.  The sample retentate can also be
recovered by backflushing (reversing the flow through of the hollow fiber membrane cartridge).
                                         100 Liters of
                                        Finished Water
                                      Sample elution and
                  1/20th for Field
    1/2 for PCR
Presumptive Testing
1/2 for Culture or
Figure 4-13. Sample Collection and Processing for Unknown Microbial Contaminants
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Figure 4-14. Field Concentrator Schematic
8.4.2  Field Screening and Processing of Sample
Field processing of the small aliquot of the field sample concentrate from the ultrafiltration
concentrator consists of field screening for microbial contaminants (Figure 4-15), which also is a
component of site characterization (see Module 3). This field screening, in turn, may result in
rapid actions to prevent further adverse consequences to safety and health of the samplers,
laboratory personnel, and the general public. It is important to remember that both field
screening by equipment and field test assays have only limited use, and any results need to be
confirmed by additional laboratory testing.
                                     Retentate Recovery
                                    Small Aliquot for Field
Commercial \
assays target \
select agents or /
toxins /
Microbials and Large
Toxins by Field

Microbials by Field
PCR Techniques
/ Reagents for select
/ agents provided by
\ some commercial
\ systems
Figure 4-15. Field Processing for Microbials
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Field screening equipment encompasses a wide range of technologies including lateral flow
chromatography, antibody identification, hand-held or field deployable PCR based assays, and
others (Table 4-15). The specific technology chosen will affect the interpretation of field results.
The Office of Justice Programs of the Department of Justice (DOJ) has provided a list of
available technologies for field screening (http://www.oip.usdoj.gov/nij/pubs-sum/190747.htm).
(The DOJ document contains neither an endorsement of any specific technology nor an
evaluation of their performance.)

Many of the available field screening assay tests (Table 4-15) are less sensitive than laboratory-
based assays by perhaps several orders of magnitude, and thus there is a potential for false
negative results. Due to possible cross-reactivity, these technologies may also lead to false
positive reactions.  The results of field screening should be used as part of a threat
characterization process and not as part of a conclusive analytical procedure.

Table 4-15. Exploratory Field Screening Techniques for Waterborne Contaminants and
Select Agents
(general class)
Screening Technique*
Waterborne Contaminants
Campylobacter spp.
E. co//0157:H7
Salmonella spp.

Select Agents
Bacillus anthracis
Clostridium botulinum A
Bmcella spp.
Francisella tularensis
Yersinia pestis

PCR and Smart tickets
* TBD = to be determined

8.4.3  Presumptive Testing for Microbials with Exploratory PCR Techniques
For presumptive testing of the field sample concentrate from the ultrafiltration concentrator,
exploratory techniques such as PCR testing may be utilized as a means to obtain faster
presumptive results for critical samples. These presumptive results may be used during the
threat evaluation (Module 2) and site characterization (Module 3) procedures.  Although PCR
techniques are widely used in the clinical and medical fields, these techniques  are still regarded
as exploratory in the field of environmental microbiology. PCR has three main benefits in a
presumptive test: 1) results can be obtained faster; 2) multiple targets can be assayed in a short
period of time; and 3) cultural methods are not available yet for some microbial contaminants of
interest. Another advantage of PCR testing is that samples could be analyzed concurrently with
the conventional established  methods.  Table 4-16 lists PCR techniques for the biological
contaminants of concern.
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Table 4-16. Exploratory Analytical Techniques for Presumptive Testing of Waterborne
Contaminants and Select Agents
general class
Testing Technique

Campy lob acter spp.
E. coli0157:H7
Salmonella spp.
Shigella spp.
Vibrio cholerae
Crypto sporidium parvum
Giardia intestinalis
Entamoeba histolytica
Toxoplasma gondii
Hepatitis A
Hepatitis E
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing

Bacillus anthracis
Clostridium botulinum A
Brucella spp.
Burkholderia pseudomallerei
Francisella tularensis
Yersinia pestis
Coxiella burnetti
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
Probe or sequencing
These viruses are not considered to pose a major threat in water
Protozoa and bacteria in the field sample concentrate are further concentrated by centrifugation
of the sample in the laboratory (Figure 4-16). Possible spores, bacteria or protozoa in the sample
are recovered in the pellet whereas viruses will be retained in the supernatant.  DNA from spores,
vegetative bacteria or protozoa is extracted from the pellet.  DNA extraction kits designed to
remove co-contaminants from environmental samples are more desirable since ultrafiltration will
tend to concentrate soil-derived PCR inhibitors (e.g., humic and fulvic acids).  The supernatant is
further concentrated by a second phase of ultrafiltration. RNA-containing viruses are the
anticipated target in a water sample; thus, a procedure for RNA extraction and purification is to
be followed. The purified RNA is used for reverse transcriptase-PCR (RT-PCR) to desired viral
RNA targets.

Primers and probes for PCR presumptive testing for waterborne and non-select agents may be
obtained  from the scientific literature.  Some commercial vendors provide primers and probes for
select agents, although these are not necessarily utilized by the LRN for its analysis.  The LRN
system utilizes a restricted set of primers and probes for detection of select agents.  (If a DNA
virus, such as variola, is strongly  suspected, a different technique will be necessary for extraction
and purification of its DNA, although variola is not considered a priority threat in water).
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                                        1/2 Retentate for PCR
                                      Bacteria & Protozoa in Pellet
                                        Viruses in Supernatant
              Primers and probes for
               water borne agents
               from the literature
Screen for Microbials by PCR and
Primers and probes for
select agents managed
 by the LRN system
Figure 4-16.  Sample Processing for Exploratory PCR Presumptive Testing

8.4.4  Confirmatory Testing for Microbials by Culture and Conventional Assays
Processing of the field sample concentrate for culture assays (Figure 4-17) consists of an initial
centrifugation step to further concentrate bacteria (vegetative cells and spores) and protozoa in
the sample. Bacteria and protozoa will be concentrated in the pellet, and viruses will remain in
the supernatant.  Protozoa are separated from the bacteria by IMS. Bacteria will remain in the
IMS supernatant (liquid phase) and the protozoa will be concentrated with the beads (solid
phase). Viruses are further concentrated for cell culture analysis. Table 4-17 lists established
confirmatory analytical techniques for waterborne and select agents.
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                                          1/2 Retentate for
                                        Culture Procedures
                                      Bacteria & Protozoa in Pellet
                                       Viruses in Supernatant
                      al Assays
Figure 4-17. Sample Processing for Confirmatory Microbiological Assays

Table 4-17.  Established Confirmatory Analytical Techniques for Waterborne
Contaminants and Select Agents
(general class)
Additional Exploratory
Waterborne Contaminants
Campylobacter spp.
E. coli0157:H7
Salmonella spp.
Shigella spp.
Vibrio cholerae
Crypto sporidium parvum
Giardia intestinalis
Entamoeba histolytica
Toxoplasma gondii
Hepatitis A
Hepatitis E
Biochemical and
Serological Tests
IFA and Microscopy
Plaque neutralization
PCR and Sequencing
PCR and Sequencing
RT-PCR and Sequencing
RT-PCR and Sequencing
RT-PCR and Sequencing
RT-PCR and Sequencing
Select Agents
Bacillus anthracis
Clostridium botulinum A
Brucella spp.
Burkholderia pseudomallerei
Francisella tularensis
Yersinia pestis
Coxiella burnetti
Biochemical and
Serological Tests
Biochemical and
Serological Tests
Biochemical and
Serological Tests
PCR and Sequencing
PCR and Sequencing

PCR and Sequencing
PCR and Sequencing
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The procedures outlined in this section are intended for use in water samples where select agents
are suspected to be present, thus these procedures should be performed in microbiology
laboratories that use appropriate Biological Safety Level practices.  For all  suspected pathogens,
refer to the CDC publication "Biosafety in Microbiological and Biomedical Laboratories," 4th
edition (HHS Publication No. 93-8395, http://www.cdc.gov/od/ohs/pdffiles/4th%20BMBL.pdf).
Some BSL requirements are summarized below, broken out by pathogen class.

Bacterial assays
Pathogenic enteric bacteria can be handled in an environmental BSL-2 laboratory. Nonetheless,
select agents should only be analyzed for presumptive identification by laboratories approved for
presumptive identification of select agents. Brucella spp. (BSL-3), Burkholderia mallei (BSL-
2), B. pseudomallei (BSL-2), Yersiniapestis (BSL-2), and Francisella tularensis (BSL-3) are
highly infectious and have caused laboratory-acquired infections. Because of the highly
infectious nature of these pathogens, consultation with a state public health laboratory is
recommended if any of these are suspected in a sample.

The solid phase of the IMS procedure is further processed by EPA Method 1623 for IF A
identification of Cryptosporidium and Giardia. The protozoa Cryptosporidium parvum, Giardia
intestinalis, Entamoeba histolytica, and Toxoplasma gondii can be handled in an environmental
BSL-2 laboratory.

Viruses in the supernatant from the centrifugation step above are further concentrated by a
second ultrafiltration to reduce the assay volume for cell culture analysis. Pathogenic enteric
viruses can be handled in an environmental BSL-2 laboratory.  Nonetheless, select agents should
only be analyzed for presumptive identification by laboratories approved for presumptive
identification of select agents. Variola (BSL-3), VEE (BSL-3) and VHF (BSL-4) are highly
infectious, and suspected samples should be referred to an LRN laboratory.  Because multiple
virus targets are pursued, the sample is likely to be inoculated onto  more than one cell line.

Public health laboratories primarily use tube cultures of mammalian cells which  are amenable
only for small inoculation volumes.  However, tube culture is a well established  method and
fairly efficient for virus detection. Infectious viruses are amplified  in the receptive cells and are
used as the source of infectious material for subsequent identification and confirmation assays.
Identification and analytical confirmation consists of neutralization assays with specific antisera.
PCR and sequencing of positive samples is also an exploratory technique that could be used to
further identify  and characterize the isolated virus. DNA sequencing is used for fingerprinting
studies and for definitive identification of pathogens.
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9   References and Resources

References and information cited or used to develop this module are listed below. The URLs of
several sources are cited throughout the text. These URLs were correct at the time of the
preparation of this document. If the document is no longer available at the URL provided, please
search the sponsoring organization's Web site or the World Wide Web for alternate sources.  A
copy of referenced documents may also be provided on the CD version of this module, although
readers should consult the referenced URL for the latest version.

AOAC. 2003a. "Home of AOAC International, The Cornerstone for Online Analytical Methods"
http ://www. aoac.org.

AOAC. 2003b. "Rapid Test Kits Test Kit Database"

ASTM, 2003, "Standards Worldwide - ASTM International" http://www.astm.org.

CDC. 1999. "Biosafety in Microbiological and Biomedical Laboratories"

CDC. 2002a. "Summary of the Laboratory Response Network"

CDC. 2002b. "Possession, Use, and Transfer of Select Agents and Toxins: Interim Final Rule;
Department of Health and Human Services, 42 CFR Part 1003; December 13, 2002"
http ://www. cdc.gov/od/sap/docs/42cfr73 .pdf.

CDC. 2003a. "What to do in an Emergency" http://www.bt.cdc.gov/emcontact/index.asp.

CDC. 2003b. "Biological Agents-Diseases Public Health Emergency"
http ://www.bt. cdc. gov/Agent/agentli st. asp.

CDC. 2003c. "Office of the Director—Select Agent Program" http://www.cdc.gov/od/sap.

CDC. 2003d. "Office of the Director-Select Agent Program FAQ"
http: //www. cdc. gov/od/sap/faq. htm.

CDC. 2003e. "Office of the Director—Select Agent Program Additional Resource Material"
http://www. cdc. gov/od/sap/addres.htm.

CDC. 2003f. "Summary of Biosafety Level-l&2 for Infectious Agents"

CDC. 2003f. "List of Select Biological Agents" http://www.cdc.gov/od/sap/docs/salist.pdf.
                                       102                     Interim Final - December 2003

                                                          MODULE 4:  Analytical Guide
Clesceri, Lenore S., Arnold E. Greenberg, Andrew D. Eaton, Editors. 1999. Standard Methods
for the Examination of Water and Wastewater, 20th edition (January 1999). A joint publication of
the Water Environment Federation, the American Water Works Association, and the American
Public Health Association, Washington, DC. ISBN 0-87553-235-7

CWC. 2003a. "CWC Regulations - Supplement No. 1 to Part 712 -Schedule 1 Chemicals"
http://www.cwc.gov/Regulations/cfr-15/part-712-s 1  html  See also
http://www.cwc.gov/Regulations/cfr-15/index html.

CWC. 2003b. "The Chemical Weapons Convention - A Quick Guide, CWC-002"
http://www.cwc.qov/lndustrv Outreach/Publications/002/cwc-b0001  html.

CWC. 2003c. "CWC Regulations - Supplement No. 1 to Part 713 -Schedule 2 Chemicals"
http ://www. cwc. gov/Regulations/cfr-15/part-713 -s 1  html.

CWC. 2003d. "CWC Regulations - Supplement No. 1 to Part 714 -Schedule 3 Chemicals"
http ://www. cwc. gov/Regulations/cfr-15/part-714-s l_html.

DOJ/NIJ. 2001. "An Introduction to Biological Agent Detection Equipment for Emergency First
Responders, NIJ Guide 101-00, December 2001"  http://www.ojp.usdoj.gov/nii/pubs-

DOT. 2003. "Welcome to the Hazmat Safety Homepage" http://hazmat.dot.gov/.

EPA and USGS. 2003. "National Environmental Methods Index" http://www.nemi.gov.

EPA. 2000. "EPA Radiological Emergency Response Plan"
http ://www. epa. gov/radiation/rert/docs/rerp-1 -OO.pdf.

EPA. 2002a. "EPA Manual of Manuals - Laboratory Analytical Methods Manuals"
http ://www. epa. gov/nerlcwww/methmans.html.

EPA. 2002b. "Setting Guidelines to Protect the Public - Information Home (EPA's Radiation
Protection Program Information)"
http ://www. epa. gov/radiation/docs/readytorespond/ready3 .htm.

EPA. 2002c. "EPA's Radiation Protection Program" http://www.epa.gov/radiation/marlap/.

EPA. 2003a. "EPA's Radiation Protection Program Information"
http://www.epa.gov/radiation/programs.htm - er.

EPA. 2003b. "EPA Quality System - Information for non-EPA Organizations"
http:/Avww. epa.gov/qualityl/exmural.html#genreqts.
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                                                          MODULE 4: Analytical Guide

EPA. 2003c. "EPA Environmental Technology Verification Home" http://www.epa.gov/etv/.

EPA. 2003d. "EPA Analytical Methods for Drinking Water and Analytical Methods Developed
by the Office of Ground Water and Drinking Water"
http ://www. epa. gov/safewater/methods/sourcalt. html.

EPA. 2003 e. "EPA Methods from the Office of Research and Development"
http ://www. epa. gov/nerlcwww/ordmeth.htm.

EPA. 2003f.  "Test Methods SW-846 On-line"
http ://www. epa. gov/epaoswer/hazwaste/test/main.htm.

EPA. 2003g. "CFR Title 40 Protection of Environment"

EPA. 2003h. "EPA Ground Water and Drinking Water Drinking Water Contaminant Candidate
List" http://www.epa.gov/safewater/ccl/cclfs.html.

EPA. 20031.  "EPA Unregulated Contaminant Monitoring Regulation"
http ://www. epa. gov/safewater/standard/ucmr/main.html.

EPA. 2003J.  "New Test Methods On-line" http://www.epa.gov/epaoswer/hazwaste/test/new-

EPA. 2003k. "ETV - Verifications" http://www.epa.gov/etv/verifications/.

EPA. 20031.  "EPA Microbiology Home Page" http://www.epa.gov/nerlcwww/.

ERT. 2003. "ERT Health and Safety" http://www.ertresponse.com/health safety/index.htm.

FEMA. 2003. "FEMA Radiological Emergency Preparedness Program"

FJC. 2000. "Reference Manual Scientific Evidence, Second Edition"
http://www.fi c.gov/public/pdfnsf/lookup/scimanOO.pdf/$file/scimanOO.pdf

ISO. 2003. "ISO - International Standard for Organization" http://www.iso.org.

NIOSH. 2003. "NIOSH - National Personal Protective Technology Laboratory"
http ://www. cdc.gov/niosh/npptl/default.html.

NIST. 2002.  "AMDIS Download Page" http://chemdata.nist.gov/mass-spc/amdis/.

NRT. 1996. "Federal Register - FEMA Federal Radiological Emergency Response Plan"
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                                                         MODULE 4: Analytical Guide

OSHA. 2002. "Safety and Health Topics Personal Protective Equipment"

OSHA. 2003a. "OSHA e-HASP Software -Version 1.0, September 2003"
http ://www. osha. gov/dts/osta/oshasoft/ehasp/.

OSHA. 2003b. "Occupational Safety and Health Administration Homepage"

UNESCO. 1995. "UNESCO's Documentary Resources—Manual on Harmful Marine
Microalgae"  http://unesdoc.unesco.org/images/0012/001220/122021eo.pdf.

US Army. 2002. "Toxic Chemical Agent Safety Standards"
http://www.usapa.army.mil/pdffiles/p385 _61.pdf.

US Coast Guard. 2001. "Chemical Hazards Response Information System"
http ://www. chrismanual. com.

USD A. 2003 a. "Animal and Plant Health Inspection Service" http://www.aphis.usda.gov.

USGS. 2003. "Methods and Data Comparability Board Home Page"
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                                                                    MODULE 4:  Analytical Guide
10  Appendices

10.1 Chemicals that appear in CWC Schedules

Table 4-18.  List of chemicals that appear in CWC Schedules 1, 2, and 3
(http://www.cwc.gov/Regulations/cfr-15/index  html)
Schedule 1 Chemical Agents
Schedule 2 Chemical Agents
Schedule 3 Chemical Agents
O-Alkyl (
                   MODULE 4:  Analytical Guide
Schedule 1 Chemical Agents
HN1: Bis(2-chloroethyl)ethylamine
HN2: Bis(2-
HNS : Tris(2-chloroethyl)amine
Alkyl (Me, Et, n-Pr or I-
DF :Methylphosphonyldifluoride
O-Alkyl(incl. Cycloalkyl)O-2-
(Me, Et, n-Pr or I-Pr)-aminoethyl
(Me, Et, n-Pr or I-Pr) phosphorites
and corresponding alkylated or
protonated salts
e.g., QL: O-Ethyl O-2-
Chlorosarin: O-Isopropyl
Chlorosoman: O-Pinacolyl

Schedule 2 Chemical Agents
dialkyl (Me, Et, n-Pr or i-Pr)-
Arsenic trichloride
2,2-Diphenyl-2-hydroxyacetic acid
N,N-Dialkyl (Me, Et, n-Pr or I-Pr)
aminoethyl-2 -chlorides and
corresponding protonated salts
•Dialkyl (Me, Et, n-Pr or I-Pr)
ioethane-2-ols and corresponding
mated salts
nption: N,N-Dimethylaminoethanol
corresponding protonated salts N,N-
lylaminoethanol and corresponding
mated salts
N,N-Dialkyl (Me, Et, n-Pr or I-Pr)
aminoethane-2-thiols and
corresponding protonated salts
Thiodiglycol: Bis(2-hydroxyethyl)
Pinacolyl alcohol: 3,3-

Schedule 3 Chemical Agents

Phosphorus pentachloride
Trimethyl phosphite
Triethyl phosphite
Dimethyl phosphite
Diethyl phosphite
Sulfur monochloride
Sulfur dichloride
Thionyl chloride
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                                                           MODULE 4:  Analytical Guide
10.2 Methods Used for the Basic Screen

Table 4-19. Titles of methods used in Table 4-3 for the basic screen.  (See Table 4-2 for
information on how to obtain these methods.)
EPA Method number
Drinking water methods
200.7, May 1994, Revision 4.4*
200.8, May 1994, Revision 5.4*
200.9, May 1994, Revision 2.2*
245.1, May 1994, Revision 3.0*
245. 2, March 1983*
335.2, March 1983
335.3, March 1983
335.4, March 1983
502.2, 1995, Revision 2.1*
524.2, 1995, Revision 4.1*
525.2, 1995, Revision 2.0*
531.1, 1995, Revision 3.1*
531.2, September 2001, Revision 1.0
549.2, 1997, Revision 1.0*
900, August 1980*
Trace Elements in Water, Solids, and Biosolids by Inductively
Coupled Plasma- Atomic Emission Spectrometry
Determination Of Trace Elements In Waters And Wastes By Inductively
Coupled Plasma Mass Spectrometry
Trace Elements in Water, Solids, and Biosolids by Stabilized
Temperature Graphite Furnace Atomic Absorption Spectrometry
Mercury (Manual Cold Vapor Technique)
Mercury (Automated Cold Vapor Technique)
Cyanide, Total (Titrimetric; Spectrophotometric)
Cyanide, Total (Colorimetric, Automated UV)
Cyanide, Total (Colorimetric, Semi-automated UV)
Volatile Organic Compounds in Water By Purge And Trap Capillary Column
Gas Chromatography with Photoionization and Electrolytic Conductivity
Detectors in Series
Measurement Of Purgeable Organic Compounds In Water By Capillary Column
Gas Chromatography /mass Spectrometry
Determination of Organic Compounds in Drinking Water By Liquid-solid
Extraction and Capillary Column Gas Chromatography /Mass Spectrometry
Measurement of N-methylcarbamoyloximes and N-methyl-carbamates
in Water by Direct Aqueous Injection HPLC with Post-Column Derivatization
Determination of Diquat and Paraquat in Drinking Water by Liquid-Solid
Extraction and High Performance Liquid Chromatography with Ultraviolet
Proscribed Procedures for the Determination of Radioactivity in Water
SW-846 methods
3535A, January 1998, Revision 1
5030B, December 1996, Revision 2
8021B, December 1996, Revision 2
8260B, December 1996, Revision 2
8270D, January 1998, Revision 4
Solid-Phase Extraction (SPE) [preparation technique for 8270D]
Purge-and-Trap for Aqueous Samples
Aromatic and Halogenated Volatiles by Gas Chromatography Using
Photoionization and/or Electrolytic Conductivity Detectors
Volatile Organic Compounds by Gas Chromatography /Mass Spectrometry
Semivolatile Organic Compounds by Gas Chromatography /Mass Spectrometry

* These methods are approved at 40 CFR Part 141 for regulatory compliance monitoring of drinking water.
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                                                            MODULE 4:  Analytical Guide
10.3 Analyte Lists for Basic Screen

Table 4-20. Analyte Lists Corresponding to Table 4-3.
Note: Laboratories may recognize these as commercially available standard mixes or
combinations thereof. This does not imply endorsement of any company, product, or service.
The standard mixes do not necessarily include all analytes that the method is capable of
determining.  For example, in list B, only 90 analytes are included, although commercially
available mixes could be selected to encompass more than 150 compounds. Laboratories should
be encouraged to include as many analytes as possible in the standards mix to increase the
breadth of the screen. Because the analyte lists are intended for the basic screen, which is
designed to produce defensible results, laboratories may wish to modify the analyte lists to
reflect their accreditations  and certifications. However, additional  analytes may become part of
the expanded screen, so laboratories may wish to include those anyway.  Analytes added to those
listed must meet the same QC acceptance criteria and be part of the overall quality system in the
laboratory, so that the added analytes will be as defensible as those listed.

The exclusion or inclusion of an analyte in the lists in this table does not reflect its potential
hazard as a water contaminant. Rather, these analytes were chosen for the convenience of
commercial availability of standard mixes.  In practice, site-specific plans and situations may be
used (and are encouraged)  to modify these lists.
Analyte Lists Corresponding to Table 4-3


1,1,1 -Trichloroethane

1 , 1 ,2-Trichloroethane

, 1 -Dichloroethene
, 1 -Dichloropropene

22' 3 3' 45' 66'-
2,3 -Dichlorobiphenyl



aldicarb sulfone

aldicarb sulfoxide

Hydroxy carbofuran
Sevin (carbaryl)
















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                   MODULE 4: Analytical Guide
Analyte Lists Corresponding to Table 4-3
1 ,3 -Dichlorobenzene
1 ,3 -Dichloropropane
1 ,4-Dichlorobenzene
allyl chloride


Butyl chloride
Carbon disulfide
Carbon tetrachloride
Cis- 1 ,2-Dichloroethene
Diethyl ether
Ethyl methacrylate
methanol (solvent)
Methyl acrylate
Methyl methacrylate
Methyl tert-butyl ether
Methylene chloride
Azinphos methyl
Demeton (mixed

Diethyl phthalate
Dimethyl phthalate
Di-n-butyl phthalate
Endosulfan I
Endosulfan II
Endosulfan sulfate
Endrin aldehyde






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                   MODULE 4:  Analytical Guide
Analyte Lists Corresponding to Table 4-3


trans- 1,2-
trans- 1,3-
trans- 1 ,4-Dichloro-2-
Vinyl chloride

Heptachlor epoxide
(Isomer B)
Indeno( 1 ,2,3 -cd)pyrene
Methyl parathion









Interim Final - December 2003

Office of Ground Water and Drinking Water
Water Security Division
December 2003
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