Method 1669

Sampling Ambient Water for Trace Metals at EPA Water Quality

Criteria Levels

July 1996

U.S. Environmental Protection Agency

Office of Water

Engineering and Analysis Division (4303)

401 M Street S.W.

Washington, D.C. 20460
Method 1669

ii July 1996

Acknowledgements

This sampling method was prepared under the direction of William A. Telliard of the Engineering

and Analysis Division (EAD) within the U.S. Environmental Agency's (EPA's) Office of Science

and Technology (OST). This sampling method was prepared under EPA Contract 68-C3-0337

by the DynCorp Environmental Programs Division, with assistance from Interface, Inc.

The following researchers contributed to the philosophy behind this sampling method. Their

contribution is gratefully acknowledged:

Shier Berman, National Research Council, Ottawa, Ontario, Canada;

Nicholas Bloom, Frontier Geosciences Inc, Seattle, Washington;

Eric Crecelius, Battelle Marine Sciences Laboratory, Sequim, Washington;

Russell Flegal, University of California/Santa Cruz, California;

Gary Gill, Texas A&M University at Galveston, Texas;

Carlton Hunt and Dion Lewis, Battelle Ocean Sciences, Duxbury, Massachusetts;

Carl Watras, Wisconsin Department of Natural Resources, Boulder Junction, Wisconsin

Additional support was provided by Ted Martin of the EPA Office of Research and

Development's Environmental Monitoring Systems Laboratory in Cincinnati, Ohio and by Arthur

Horowitz of the U.S. Geological Survey.

This version of the method was prepared after observations of sampling teams from the University

of California at Santa Cruz, the Wisconsin Department of Natural Resources, the U.S. Geological

Survey, and Battelle Ocean Sciences. The assistance of personnel demonstrating the sampling

techniques used by these institutions is gratefully acknowledged.

Disclaimer

This sampling method has been reviewed and approved for publication by the Analytical Methods

Staff within the Engineering and Analysis Division of the U.S. Environmental Protection Agency.

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

recommendation for use.

Further Information

For further information, contact:

W.A. Telliard

Engineering and Analysis Division (4303)

U.S. Environmental Protection Agency

401 M Street, SW

Washington, DC 20460

Phone: 202/260–7134

Fax: 202/260–7185
Method 1669

July 1996 iii

Introduction

This sampling method was designed to support water quality monitoring programs authorized

under the Clean Water Act. Section 304(a) of the Clean Water Act requires EPA to publish water

quality criteria that reflect the latest scientific knowledge concerning the physical fate (e.g.,

concentration and dispersal) of pollutants, the effects of pollutants on ecological and human

health, and the effect of pollutants on biological community diversity, productivity, and stability.

Section 303 of the Clean Water Act requires states to set a water quality standard for each body

of water within its boundaries. A state water quality standard consists of a designated use or uses

of a waterbody or a segment of a waterbody, the water quality criteria that are necessary to protect

the designated use or uses, and an antidegradation policy. These water quality standards serve two

purposes: (1) they establish the water quality goals for a specific waterbody, and (2) they are the

basis for establishing water quality-based treatment controls and strategies beyond the technologybased controls required by Sections 301(b) and 306 of the Clean Water Act.

In defining water quality standards, the state may use narrative criteria, numeric criteria, or both.

However, the 1987 amendments to the Clean Water Act required states to adopt numeric criteria

for toxic pollutants (designated in Section 307(a) of the Act) based on EPA Section 304(a) criteria

or other scientific data, when the discharge or presence of those toxic pollutants could reasonably

be expected to interfere with designated uses.

In some cases, these water quality criteria are as much as 280 times lower than those achievable

using existing EPA methods and required to support technology-based permits. Therefore, this

sampling method, and the analytical methods referenced in Table 1 of this document, were

developed by EPA to specifically address state needs for measuring toxic metals at water quality

criteria levels, when such measurements are necessary to protect designated uses in state water

quality standards. The latest criteria published by EPA are those listed in the National Toxics Rule

(57 FR 60848) and the Stay of Federal Water Quality Criteria for Metals (60 FR 22228). These

rules include water quality criteria for 13 metals, and it is these criteria on which this sampling

method and the referenced analytical methods are based.

In developing these methods, EPA found that one of the greatest difficulties in measuring

pollutants at these levels was precluding sample contamination during collection, transport, and

analysis. The degree of difficulty, however, is highly dependent on the metal and site-specific

conditions. This method, therefore, is designed to provide the level of protection necessary to

preclude contamination in nearly all situations. It is also designed to provide the procedures

necessary to produce reliable results at the lowest possible water quality criteria published by EPA.

In recognition of the variety of situations to which this method may be applied, and in recognition

of continuing technological advances, the method is performance-based. Alternative procedures

may be used, so long as those procedures are demonstrated to yield reliable results.

Requests for additional copies of this method should be directed to:

U.S. EPA NCEPI

11029 Kenwood Road

Cincinnati, OH 45242

513/489–8190
Method 1669

iv July 1996

Note: This document is intended as guidance only. Use of the terms "must," "may,"

and "should" are included to mean that EPA believes that these procedures must, may,

or should be followed in order to produce the desired results when using this guidance. 

In addition, the guidance is intended to be performance-based, in that the use of less

stringent procedures may be used so long as neither samples nor blanks are

contaminated when following those modified procedures. Because the only way to

measure the performance of the modified procedures is through the collection and

analysis of uncontaminated blank samples in accordance with this guidance and the

referenced methods, it is highly recommended that any modifications be thoroughly

evaluated and demonstrated to be effective before field samples are collected.
July 1996 1

Method 1669

Sampling Ambient Water for Determination of Metals at EPA Water Quality Criteria

Levels

1.0 Scope and Application

1.1 This method is for the collection and filtration of ambient water samples for subsequent

determination of total and dissolved metals at the levels listed in Table 1. It is designed to

support the implementation of water quality monitoring and permitting programs

administered under the Clean Water Act.

1.2 This method is applicable to the metals listed below and other metals, metals species, and

elements amenable to determination at trace levels. 

Analyte Symbol

Chemical Abstract Services

Registry Number (CASRN)

Antimony (Sb) 7440-36-0

Arsenic (As) 7440-38-2

Cadmium (Cd) 7440-43-9

Chromium (III) Cr+3 16065-83-1

Chromium (VI) Cr+6 18540-29-9

Copper (Cu) 7440-50-8

Lead (Pb) 7439-92-1

Mercury (Hg) 7439-97-6

Nickel (Ni) 7440-02-0

Selenium (Se) 7782-49-2

Silver (Ag) 7440-22-4

Thallium (Tl) 7440-28-0

Zinc (Zn) 7440-66-6

1.3 This method is accompanied by the 1600 series methods listed in Table 1. These methods

include the sample handling, analysis, and quality control procedures necessary for reliable

determination of trace metals in aqueous samples.

1.4 This method is not intended for determination of metals at concentrations normally found

in treated and untreated discharges from industrial facilities. Existing regulations (40 CFR

Parts 400-500) typically limit concentrations in industrial discharges to the mid to high

part-per-billion (ppb) range, whereas ambient metals concentrations are normally in the

low part-per-trillion (ppt) to low ppb range. This guidance is therefore directed at the

collection of samples to be measured at or near the levels listed in Table 1. Actual

concentration ranges to which this guidance is applicable will be dependent on the sample

matrix, dilution levels, and other laboratory operating conditions.

1.5 The ease of contaminating ambient water samples with the metal(s) of interest and

interfering substances cannot be overemphasized. This method includes sampling

techniques that should maximize the ability of the sampling team to collect samples reliably

and eliminate sample contamination. These techniques are given in Section 8.0 and are

based on findings of researchers performing trace metals analyses (References 1-9).
Method 1669

2 July 1996

1.6 Clean and Ultraclean—The terms "clean" and "ultraclean" have been used in other Agency

guidance to describe the techniques needed to reduce or eliminate contamination in trace

metals determinations. These terms are not used in this sampling method due to a lack of

exact definitions. However, the information provided in this method is consistent with

summary guidance on clean and ultraclean techniques (Reference 10).

1.7 This sampling method follows the EPA Environmental Methods Management Council's

"Format for Method Documentation" (Reference 11).

1.8 Method 1669 is "performance-based"; i.e., an alternate sampling procedure or technique

may be used, so long as neither samples nor blanks are contaminated when following the

alternate procedures. Because the only way to measure the performance of the alternate

procedures is through the collection and analysis of uncontaminated blank samples in

accordance with this guidance and the methods referenced in Table 1, it is highly

recommended that any modifications be thoroughly evaluated and demonstrated to be

effective before field samples are collected. Section 9.2 provides additional details on the

tests and documentation required to support equivalent performance.

1.9 For dissolved metal determinations, samples must be filtered through a 0.45 μm capsule

filter at the field site. The filtering procedures are described in this method. The filtered

samples may be preserved in the field or transported to the laboratory for preservation.

Procedures for field preservation are detailed in this sampling method; procedures for

laboratory preservation are provided in the methods referenced in Table 1. Preservation

requirements are summarized in Table 2.

1.10 The procedures in this method are for use only by personnel thoroughly trained in the

collection of samples for determination of metals at ambient water quality control levels.

2.0 Summary of Method

2.1 Before samples are collected, all sampling equipment and sample containers are cleaned

in a laboratory or cleaning facility using detergent, mineral acids, and reagent water as

described in the methods referenced in Table 1. The laboratory or cleaning facility is

responsible for generating an acceptable equipment blank to demonstrate that the sampling

equipment and containers are free from trace metals contamination before they are shipped

to the field sampling team. An acceptable blank is one that is free from contamination

below the minimum level (ML) specified in the referenced analytical method (Section 9.3).

2.2 After cleaning, sample containers are filled with weak acid solution, individually doublebagged, and shipped to the sampling site. All sampling equipment is also bagged for

storage or shipment.

NOTE: EPA has found that, in some cases, it may be possible to empty the weak acid solution from the bottle

immediately prior to transport to the field site. In this case, the bottle should be refilled with reagent water (Section 7.1).

2.3 The laboratory or cleaning facility must prepare a large carboy or other appropriate clean

container filled with reagent water (Section 7.1) for use with collection of field blanks

during sampling activities. The reagent-water-filled container should be shipped to the

field site and handled as all other sample containers and sampling equipment. At least one

field blank should be processed per site, or one per every ten samples, whichever is more

frequent (Section 9.4). If samples are to be collected for determination of trivalent
Method 1669

July 1996 3

chromium, the sampling team processes additional QC aliquots are processed as described

in Section 9.6.

2.4 Upon arrival at the sampling site, one member of the two-person sampling team is

designated as "dirty hands"; the second member is designated as "clean hands." All

operations involving contact with the sample bottle and transfer of the sample from the

sample collection device to the sample bottle are handled by the individual designated as

"clean hands." "Dirty hands" is responsible for preparation of the sampler (except the

sample container itself), operation of any machinery, and for all other activities that do not

involve direct contact with the sample.

2.5 All sampling equipment and sample containers used for metals determinations at or near

the levels listed in Table 1 must be nonmetallic and free from any material that may contain

metals.

2.6 Sampling personnel are required to wear clean, nontalc gloves at all times when handling

sampling equipment and sample containers. 

2.7 In addition to processing field blanks at each site, a field duplicate must be collected at

each sampling site, or one field duplicate per every 10 samples, whichever is more frequent

(Section 9.5). Section 9.0 gives a complete description of quality control requirements.

2.8 Sampling

2.8.1 Whenever possible, samples are collected facing upstream and upwind to minimize

introduction of contamination. 

2.8.2 Samples may be collected while working from a boat or while on land.

2.8.3 Surface samples are collected using a grab sampling technique. The principle of the

grab technique is to fill a sample bottle by rapid immersion in water and capping

to minimize exposure to airborne particulate matter.

2.8.4 Subsurface samples are collected by suction of the sample into an immersed sample

bottle or by pumping the sample to the surface.

2.9 Samples for dissolved metals are filtered through a 0.45 μm capsule filter at the field site.

After filtering, the samples are double-bagged and iced immediately. Sample containers

are shipped to the analytical laboratory. The sampling equipment is shipped to the

laboratory or cleaning facility for recleaning.

2.10 Acid preservation of samples is performed in the field or in the laboratory. Field

preservation is necessary for determinations of trivalent chromium. It has also been shown

that field preservation can increase sample holding times for hexavalent chromium to 30

days; therefore it is recommended that preservation of samples for hexavalent chromium

be performed in the field. For other metals, however, the sampling team may prefer to

utilize laboratory preservation of samples to expedite field operations and to minimize the

potential for sample contamination.

2.11 Sampling activities must be documented through paper or computerized sample tracking

systems.
Method 1669

4 July 1996

3.0 Definitions

3.1 Apparatus—Throughout this method, the sample containers, sampling devices,

instrumentation, and all other materials and devices used in sample collection, sample

processing, and sample analysis activities will be referred to collectively as the Apparatus.

3.2 Definitions of other terms are given in the Glossary (Section 15.0) at the end of this

method.

4.0 Contamination and Interferences

4.1 Contamination Problems in Trace Metals Analysis

4.1.1 Preventing ambient water samples from becoming contaminated during the

sampling and analytical process is the greatest challenge faced in trace metals

determinations. In recent years, it has been shown that much of the historical trace

metals data collected in ambient water are erroneously high because the

concentrations reflect contamination from sampling and analysis rather than

ambient levels (Reference 12). Therefore, it is imperative that extreme care be

taken to avoid contamination when collecting and analyzing ambient water samples

for trace metals.

4.1.2 There are numerous routes by which samples may become contaminated. Potential

sources of trace metals contamination during sampling include metallic or metalcontaining sampling equipment, containers, labware (e.g. talc gloves that contain

high levels of zinc), reagents, and deionized water; improperly cleaned and stored

equipment, labware, and reagents; and atmospheric inputs such as dirt and dust

from automobile exhaust, cigarette smoke, nearby roads, bridges, wires, and poles.

Even human contact can be a source of trace metals contamination. For example,

it has been demonstrated that dental work (e.g., mercury amalgam fillings) in the

mouths of laboratory personnel can contaminate samples that are directly exposed

to exhalation (Reference 3).

4.2 Contamination Control

4.2.1 Philosophy—The philosophy behind contamination control is to ensure that any

object or substance that contacts the sample is nonmetallic and free from any

material that may contain metals of concern.

4.2.1.1 The integrity of the results produced cannot be compromised by

contamination of samples. Requirements and suggestions for controlling

sample contamination are given in this sampling method and in the

analytical methods referenced in Table 1.

4.2.1.2 Substances in a sample or in the surrounding environment cannot be

allowed to contaminate the Apparatus used to collect samples for trace

metals measurements. Requirements and suggestions for protecting the

Apparatus are given in this sampling method and in the methods referenced

in Table 1.

4.2.1.3 While contamination control is essential, personnel health and safety remain

the highest priority. Requirements and suggestions for personnel safety are
Method 1669

July 1996 5

given in Section 5 of this sampling method and in the methods referenced

in Table 1.

4.2.2 Avoiding contamination—The best way to control contamination is to completely

avoid exposure of the sample and Apparatus to contamination in the first place.

Avoiding exposure means performing operations in an area known to be free from

contamination. Two of the most important factors in avoiding/reducing sample

contamination are (1) an awareness of potential sources of contamination and (2)

strict attention to work being performed. Therefore, it is imperative that the

procedures described in this method be carried out by well trained, experienced

personnel. Documentation of training should be kept on file and readily available

for review.

4.2.2.1 Minimize exposure—The Apparatus that will contact samples or blanks

should only be opened or exposed in a clean room, clean bench, glove box,

or clean plastic bag, so that exposure to atmospheric inputs is minimized.

When not being used, the Apparatus should be covered with clean plastic

wrap, stored in the clean bench or in a plastic box or glove box, or bagged

in clean, colorless zip-type bags. Minimizing the time between cleaning and

use will also reduce contamination.

4.2.2.2 Wear gloves—Sampling personnel must wear clean, nontalc gloves (Section

6.7) during all operations involving handling of the Apparatus, samples, and

blanks. Only clean gloves may touch the Apparatus. If another object or

substance is touched, the glove(s) must be changed before again handling

the Apparatus. If it is even suspected that gloves have become

contaminated, work must be halted, the contaminated gloves removed, and

a new pair of clean gloves put on. Wearing multiple layers of clean gloves

will allow the old pair to be quickly stripped with minimal disruption to the

work activity.

4.2.2.3 Use metal-free Apparatus—All Apparatus used for metals determinations

at the levels listed in Table 1 must be nonmetallic and free of material that

may contain metals. When it is not possible to obtain equipment that is

completely free of the metal(s) of interest, the sample should not come into

direct contact with the equipment. 

4.2.2.3.1 Construction materials—Only the following materials

should come in contact with samples: fluoropolymer (FEP,

PTFE), conventional or linear polyethylene, polycarbonate,

polysulfone, polypropylene, or ultrapure quartz. PTFE is

less desirable than FEP because the sintered material in

PTFE may contain contaminants and is susceptible to

serious memory effects (Reference 6). Fluoropolymer or

glass containers should be used for samples that will be

analyzed for mercury because mercury vapors can diffuse in

or out of other materials, resulting either in contamination

or low-biased results (Reference 3). Metal must not be used

under any circumstance. Regardless of construction, all

materials that will directly or indirectly contact the sample

must be cleaned using the procedures described in the
Method 1669

6 July 1996

referenced analytical methods (see Table 1) and must be

known to be clean and metal-free before proceeding.

4.2.2.3.2 The following materials have been found to contain trace

metals and must not be used to hold liquids that come in

contact with the sample or must not contact the sample,

unless these materials have been shown to be free of the

metals of interest at the desired level: Pyrex, Kimax,

methacrylate, polyvinylchloride, nylon, and Vycor

(Reference 6). In addition, highly colored plastics, paper

cap liners, pigments used to mark increments on plastics,

and rubber all contain trace levels of metals and must be

avoided (Reference 13).

4.2.2.3.3 Serialization—Serial numbers should be indelibly marked or

etched on each piece of Apparatus so that contamination

can be traced, and logbooks should be maintained to track

the sample from the container through the sampling process

to shipment to the laboratory. Chain-of-custody procedures

may also be used if warranted so that contamination can be

traced to particular handling procedures or lab personnel.

4.2.2.3.4 The Apparatus should be clean when the sampling team

receives it. If there are any indications that the Apparatus is

not clean (e.g., a ripped storage bag), an assessment of the

likelihood of contamination must be made. Sampling must

not proceed if it is possible that the Apparatus is

contaminated. If the Apparatus is contaminated, it must be

returned to the laboratory or cleaning facility for proper

cleaning before any sampling activity resumes.

4.2.2.3.5 Details for recleaning the Apparatus between collection of

individual samples are provided in Section 10.0.

4.2.2.4 Avoid sources of contamination—Avoid contamination by being aware of

potential sources and routes of contamination.

4.2.2.4.1 Contamination by carryover—Contamination may occur

when a sample containing low concentrations of metals is

processed immediately after a sample containing relatively

high concentrations of these metals. At sites where more

than one sample will be collected, the sample known or

expected to contain the lowest concentration of metals

should be collected first with the sample containing the

highest levels collected last (Section 8.1.4). This will help

minimize carryover of metals from high- concentration

samples to low- concentration samples. If the sampling

team does not have prior knowledge of the waterbody, or

when necessary, the sample collection system should be

rinsed with dilute acid and reagent water between samples

and followed by collection of a field blank (Section 10.3).
Method 1669

July 1996 7

4.2.2.4.2 Contamination by samples—Significant contamination of

the Apparatus may result when untreated effluents, inprocess waters, landfill leachates, and other samples

containing mid- to high-level concentrations of inorganic

substances are processed. As stated in Section 1.0, this

sampling method is not intended for application to these

samples, and samples containing high concentrations of

metals must not be collected, processed, or shipped at the

same time as samples being collected for trace metals

determinations.

4.2.2.4.3 Contamination by indirect contact—Apparatus that may not

directly contact samples may still be a source of

contamination. For example, clean tubing placed in a dirty

plastic bag may pick up contamination from the bag and

subsequently transfer the contamination to the sample.

Therefore, it is imperative that every piece of the Apparatus

that is directly or indirectly used in the collection of ambient

water samples be cleaned as specified in the analytical

method(s) referenced in Table 1.

4.2.2.4.4 Contamination by airborne particulate matter—Less

obvious substances capable of contaminating samples

include airborne particles. Samples may be contaminated by

airborne dust, dirt, particulate matter, or vapors from

automobile exhaust; cigarette smoke; nearby corroded or

rusted bridges, pipes, poles, or wires; nearby roads; and

even human breath (Section 4.1.2). Whenever possible, the

sampling activity should occur as far as possible from

sources of airborne contamination (Section 8.1.3). Areas

where nearby soil is bare and subject to wind erosion should

be avoided.

4.3 Interferences—Interferences resulting from samples will vary considerably from source to

source, depending on the diversity of the site being sampled. If a sample is suspected of

containing substances that may interfere in the determination of trace metals, sufficient

sample should be collected to allow the laboratory to identify and overcome interference

problems.

5.0 Safety

5.1 The toxicity or carcinogenicity of the chemicals used in this method has not been precisely

determined; however, these chemicals should be treated as a potential health hazard.

Exposure should be reduced to the lowest possible level. Sampling teams are responsible

for maintaining a current awareness file of OSHA regulations for the safe handling of the

chemicals specified in this method. A reference file of Material Safety Data Sheets should

also be made available to all personnel involved in sampling. It is also suggested that the

organization responsible perform personal hygiene monitoring of each sampling team

member who uses this method and that the results of this monitoring be made available

to the member.
Method 1669

8 July 1996

5.2 Operating in and around waterbodies carries the inherent risk of drowning. Life jackets

must be worn when operating from a boat, when sampling in more than a few feet of

water, or when sampling in swift currents.

5.3 Collecting samples in cold weather, especially around cold water bodies, carries the risk

of hypothermia, and collecting samples in extremely hot and humid weather carries the risk

of dehydration and heat stroke. Sampling team members should wear adequate clothing

for protection in cold weather and should carry an adequate supply of water or other

liquids for protection against dehydration in hot weather.

6.0 Apparatus and Materials

NOTE: Brand names, suppliers, and part numbers are for illustration only and no endorsement is implied. Equivalent

performance may be achieved using apparatus and materials other than those specified here. Meeting the performance requirements

of this method is the responsibility of the sampling team and laboratory.

6.1 All sampling equipment and sample containers must be precleaned in a laboratory or

cleaning facility, as described in the methods referenced in Table 1, before they are shipped

to the field site. Performance criteria for equipment cleaning is described in the referenced

methods. To minimize difficulties in sampling, the equipment should be packaged and

arranged to minimize field preparation.

6.2 Materials such as gloves (Section 6.7), storage bags (Section 6.8), and plastic wrap (Section

6.9), may be used new without additional cleaning unless the results of the equipment blank

pinpoint any of these materials as a source of contamination. In this case, either a different

supplier must be obtained or the materials must be cleaned.

6.3 Sample Bottles—Fluoropolymer (FEP, PTFE), conventional or linear polyethylene,

polycarbonate, or polypropylene; 500 mL or 1 L with lids. If mercury is a target analyte,

fluoropolymer or glass bottles should be used. Refer to the methods referenced in Table

1 for bottle cleaning procedures.

6.3.1 Cleaned sample bottles should be filled with 0.1% HCl (v/v). In some cases, it may

be possible to empty the weak acid solution from the sample bottle immediately

prior to transport to the field site. In this case, the bottle should be refilled with

reagent water (Section 7.1).

6.3.2 Whenever possible, sampling devices should be cleaned and prepared for field use

in a class 100 clean room. Preparation of the devices in the field should be done

within the glove bag (Section 6.6). Regardless of design, sampling devices must be

constructed of nonmetallic material (Section 4.2.2.3.1) and free from material that

contains metals. Fluoropolymer or other material shown not to adsorb or

contribute mercury must be used if mercury is a target analyte; otherwise,

polyethylene, polycarbonate, or polypropylene are acceptable. Commercially

available sampling devices may be used provided that any metallic or metalcontaining parts are replaced with parts constructed of nonmetallic material.

6.4 Surface Sampling Devices—Surface samples are collected using a grab sampling technique.

Samples may be collected manually by direct submersion of the bottle into the water or by

using a grab sampling device. Examples of grab samplers are shown in Figures 1 and 2

and may be used at sites where depth profiling is neither practical nor necessary.
Method 1669

July 1996 9

6.4.1 The grab sampler in Figure 1 consists of a heavy fluoropolymer collar fastened to

the end of a 2-m-long polyethylene pole, which serves to remove the sampling

personnel from the immediate vicinity of the sampling point. The collar holds the

sample bottle. A fluoropolymer closing mechanism, threaded onto the bottle,

enables the sampler to open and close the bottle under water, thereby avoiding

surface microlayer contamination (Reference 14). Polyethylene, polycarbonate, and

polypropylene are also acceptable construction materials unless mercury is a target

analyte. Assembly of the cleaned sampling device is as follows (refer to Figure 1):

6.4.1.1 Thread the pull cord (with the closing mechanism attached) through the

guides and secure the pull ring with a simple knot. Screw a sample bottle

onto the closing device and insert the bottle into the collar. Cock the

closing plate so that the plate is pushed away from the operator.

6.4.1.2 The cleaned and assembled sampling device should be stored in a double

layer of large, clean zip-type polyethylene bags or wrapped in two layers of

clean polyethylene wrap if it will not be used immediately.

6.4.2 An alternate grab sampler design is shown in Figure 2. This grab sampler is used

for discrete water samples and is constructed so that a capped clean bottle can be

submerged, the cap removed, sample collected, and bottle recapped at a selected

depth. This device eliminates sample contact with conventional samplers (e.g.,

Niskin bottles), thereby reducing the risk of extraneous contamination. Because a

fresh bottle is used for each sample, carryover from previous samples is eliminated

(Reference 15).

6.5 Subsurface Sampling Devices—Subsurface sample collection may be appropriate in lakes

and sluggish deep river environments or where depth profiling is determined to be

necessary. Subsurface samples are collected by pumping the sample into a sample bottle.

Examples of subsurface collection systems include the jar system device shown in Figure

3 and described in Section 6.5.1 or the continuous-flow apparatus shown in Figure 4 and

described in Section 6.5.2. 

6.5.1 Jar sampler (Reference 14)—The jar sampler (Figure 3) is comprised of a heavy

fluoropolymer 1-L jar with a fluoropolymer lid equipped with two 1/4 in.

fluoropolymer fittings. Sample enters the jar through a short length of

fluoropolymer tubing inserted into one fitting. Sample is pulled into the jar by

pumping on fluoropolymer tubing attached to the other fitting. A thick

fluoropolymer plate supports the jar and provides attachment points for a

fluoropolymer safety line and fluoropolymer torpedo counterweight.

6.5.1.1 Advantages of the jar sampler for depth sampling are (1) all wetted surfaces

are fluoropolymer and can be rigorously cleaned; (2) the sample is collected

into a sample jar from which the sample is readily recovered, and the jar can

be easily recleaned; (3) the suction device (a peristaltic or rotary vacuum

pump, Section 6.15) is located in the boat, isolated from the sampling jar;

(4) the sampling jar can be continuously flushed with sample, at sampling

depth, to equilibrate the system; and (5) the sample does not travel through

long lengths of tubing that are more difficult to clean and keep clean

(Reference 14). In addition, the device is designed to eliminate atmospheric

contact with the sample during collection.
Method 1669

10 July 1996

6.5.1.2 To assemble the cleaned jar sampler, screw the torpedo weight onto the

machined bolt attached to the support plate of the jar sampler. Attach a

section of the 1/4 in. o.d. tubing to the jar by inserting the tubing into the

fitting on the lid and pushing down into the jar until approximately 8 cm

from the bottom. Tighten the fitting nut securely. Attach the solid safety

line to the jar sampler using a bowline knot to the loop affixed to the

support plate.

6.5.1.3 For the tubing connecting the pump to the sampler, tubing lengths of up to

12 m have been used successfully (Reference 14).

6.5.2 Continuous-flow sampler (References 16-17)—This sampling system, shown in

Figure 4, consists of a peristaltic or submersible pump and one or more lengths of

precleaned fluoropolymer or styrene/ethylene/butylene/ silicone (SEBS) tubing.

A filter is added to the sampling train when sampling for dissolved metals.

6.5.2.1 Advantages of this sampling system include (1) all wetted surfaces are

fluoropolymer or SEBS and can be readily cleaned; (2) the suction device

is located in the boat, isolated from the sample bottle; (3) the sample does

not travel through long lengths of tubing that are difficult to clean and keep

clean; and (4) in-line filtration is possible, minimizing field handling

requirements for dissolved metals samples.

6.5.2.2 The sampling team assembles the system in the field as described in Section

8.2.8. System components include an optional polyethylene pole to remove

sampling personnel from the immediate vicinity of the sampling point and

the pump, tubing, filter, and filter holder listed in Sections 6.14 and 6.15.

6.6 Field-Portable Glove Bag—I2R, Model R-37-37H (nontalc), or equivalent. Alternately,

a portable glove box may be constructed with a nonmetallic (PVC pipe or other suitable

material) frame and a frame cover made of an inexpensive, disposable, nonmetallic

material (e.g., a thin-walled polyethylene bag) (Reference 7).

6.7 Gloves—Clean, nontalc polyethylene, latex, vinyl, or PVC; various lengths. Shoulderlength gloves are needed if samples are to be collected by direct submersion of the sample

bottle into the water or when sampling for mercury.

6.7.1 Gloves, shoulder-length polyethylene—Associated Bag Co., Milwaukee, WI, 66-3-

301, or equivalent.

6.7.2 Gloves, PVC—Fisher Scientific Part No. 11-394-100B, or equivalent.

6.8 Storage Bags—Clean, zip-type, nonvented, colorless polyethylene (various sizes).

6.9 Plastic Wrap—Clean, colorless polyethylene.

6.10 Cooler—Clean, nonmetallic, with white interior for shipping samples.

6.11 Ice or Chemical Refrigerant Packs—To keep samples chilled in the cooler during

shipment.

6.12 Wind Suit—Pamida, or equivalent.
Method 1669

July 1996 11

NOTE: This equipment is necessary only for collection of metals, such as mercury, that are known to have elevated atmospheric

concentrations.

6.12.1 An unlined, long-sleeved wind suit consisting of pants and jacket and constructed

of nylon or other synthetic fiber is worn when sampling for mercury to prevent

mercury adsorbed onto cotton or other clothing materials from contaminating

samples. 

6.12.2 Washing and drying—The wind suit is washed by itself or with other wind suits only

in a home or commercial washing machine and dried in a clothes dryer. The

clothes dryer must be thoroughly vacuumed, including the lint filter, to remove all

traces of lint before drying. After drying, the wind suit is folded and stored in a

clean polyethylene bag for shipment to the sample site.

6.13 Boat

6.13.1 For most situations (e.g., most metals under most conditions), the use of an

existing, available boat is acceptable. A flat-bottom, Boston Whaler-type boat is

preferred because sampling materials can be stored with reduced chance of tipping.

6.13.1.1 Immediately before use, the boat should be washed with water from

the sampling site away from any sampling points to remove any dust

or dirt accumulation.

6.13.1.2 Samples should be collected upstream of boat movement.

6.13.2 For mercury, and for situations in which the presence of contaminants cannot

otherwise be controlled below detectable levels, the following equipment and

precautions may be necessary:

6.13.2.1 A metal-free (e.g., fiberglass) boat, along with wooden or fiberglass

oars. Gasoline- or diesel-fueled boat motors should be avoided

when possible because the exhaust can be a source of

contamination. If the body of water is large enough to require use

of a boat motor, the engine should be shut off at a distance far

enough from the sampling point to avoid contamination, and the

sampling team should manually propel the boat to the sampling

point. Samples should be collected upstream of boat movement.

6.13.2.2 Before first use, the boat should be cleaned and stored in an area

that minimizes exposure to dust and atmospheric particles. For

example, cleaned boats should not be stored in an area that would

allow exposure to automobile exhaust or industrial pollution.

6.13.2.3 The boat should be frequently visually inspected for possible

contamination.

6.13.2.4 After sampling, the boat should be returned to the laboratory or

cleaning facility, cleaned as necessary, and stored away from any

sources of contamination until next use.
Method 1669

12 July 1996

6.14 Filtration Apparatus—Required when collecting samples for dissolved metals

determinations.

6.14.1 Filter—0.45 μm, 15 mm diameter or larger, tortuous-path capsule filters

(Reference 18), Gelman Supor 12175, or equivalent.

6.14.2 Filter holder—For mounting filter to the gunwale of the boat. Rod or pipe made

from plastic material and mounted with plastic clamps.

NOTE: A filter holder may not be required if one or a few samples are to be collected. For these cases, it may only be necessary

to attach the filter to the outlet of the tubing connected to the pump.

6.15 Pump and Pump Apparatus—Required for use with the jar sampling system (Section 6.5.1)

or the continuous-flow system (Section 6.5.2). Peristaltic pump; 115 V a.c., 12 V d.c.,

internal battery, variable-speed, single-head, Cole-Parmer, portable, "Masterflex L/S,"

Catalog No. H-07570-10 drive with Quick Load pump head, Catalog No. H-07021-24,

or equivalent.

NOTE: Equivalent pumps may include rotary vacuum, submersible, or other pumps free from metals and suitable to meet the

site-specific depth sampling needs.

6.15.1 Cleaning—Peristaltic pump modules do not require cleaning. However, nearly all

peristaltic pumps contain a metal head and metal controls. Touching the head or

controls necessitates changing of gloves before touching the Apparatus. If a

submersible pump is used, a large volume of sample should be pumped to clean

the stainless steel shaft (hidden behind the impeller) that comes in contact with the

sample. Pumps with metal impellers should not be used.

6.15.2 Tubing—For use with peristaltic pump. SEBS resin, approximately 3/8 in. i.d. by

approximately 3 ft, Cole-Parmer size 18, Cat. No. G-06464-18, or approximately

1/4 in. i.d., Cole-Parmer size 17, Catalog No. G-06464-17, or equivalent. Tubing

is cleaned by soaking in 5-10% HCl solution for 8-24 hours, rinsing with reagent

water in a clean bench in a clean room, and drying in the clean bench by purging

with mercury-free air or nitrogen. After drying, the tubing is double-bagged in

clear polyethylene bags, serialized with a unique number, and stored until use. 

6.15.3 Tubing—For connection to peristaltic pump tubing. Fluoropolymer, 3/8 or

1/4 in. o.d., in lengths as required to reach the point of sampling. If sampling will

be at some depth from the end of a boom extended from a boat, sufficient tubing

to extend to the end of the boom and to the depth will be required. Cleaning of

the fluoropolymer can be the same as cleaning the tubing for the rotary vacuum

pump (Section 6.15.1.2). If necessary, more aggressive cleaning (e.g., concentrated

nitric acid) may be used.

6.15.4 Batteries to operate submersible pump—12 V, 2.6 amp, gel cell, YUASA

NP2.6-12, or equivalent. A 2 amp fuse connected at the positive battery terminal

is strongly recommended to prevent short circuits from overheating the battery.

A 12 V, lead-acid automobile or marine battery may be more suitable for extensive

pumping.
Method 1669

July 1996 13

6.15.5 Tubing connectors—Appropriately sized PVC, clear polyethylene, or

fluoropolymer "barbed" straight connectors cleaned as the tubing above. Used to

connect multiple lengths of tubing.

6.16 Carboy—For collection and storage of dilute waste acids used to store bottles.

6.17 Apparatus—For field preservation of aliquots for trivalent chromium determinations.

6.17.1 Fluoropolymer forceps—1 L fluoropolymer jar, and 30 mL fluoropolymer vials

with screw-caps (one vial per sample and blank). It is recommended that 1 mL of

ultrapure nitric acid (Section 7.3) be added to each vial prior to transport to the

field to simplify field handling activities (See Section 8.4.4.6).

6.17.2 Filters—0.4 μm, 47 mm polycarbonate Nuclepore (or equivalent). Filters are

cleaned as follows. Fill a 1 L fluoropolymer jar approximately two-thirds full with

1 N nitric acid. Using fluoropolymer forceps, place individual filters in the

fluoropolymer jar. Allow the filters to soak for 48 hours. Discard the acid, and

rinse five times with reagent water. Fill the jar with reagent water, and soak the

filters for 24 hours. Remove the filters when ready for use, and using

fluoropolymer forceps, place them on the filter apparatus (Section 6.17.3).

6.17.3 Vacuum filtration apparatus—Millipore 47 mm size, or equivalent, vacuum pump

and power source (and extension cords, if necessary) to operate the pump.

6.17.4 Eppendorf auto pipet and colorless pipet tips (100-1000 μL)

6.17.5 Wrist-action shaker—Burrel or equivalent.

6.17.6 Fluoropolymer wash bottles—One filled with reagent water (Section 7.1) and one

filled with high- purity 10% HCl (Section 7.4.4), for use in rinsing forceps and pipet

tips.

7.0 Reagents and Standards

7.1 Reagent Water—Water in which the analytes of interest and potentially interfering

substances are not detected at the Method Detection Limit (MDL) of the analytical method

used for analysis of samples. Prepared by distillation, deionization, reverse osmosis,

anodic/cathodic stripping voltammetry, or other techniques that remove the metal(s) and

potential interferent(s). A large carboy or other appropriate container filled with reagent

water must be available for the collection of field blanks.

7.2 Nitric Acid—Dilute, trace-metal grade, shipped with sampling kit for cleaning equipment

between samples.

7.3 Sodium Hydroxide—Concentrated, 50% solution for use when field-preserving samples

for hexavalent chromium determinations (Section 8.4.5).

7.4 Reagents—For field-processing aliquots for trivalent chromium determinations

7.4.1 Nitric Acid, Ultrapure—For use when field-preserving samples for trivalent

chromium determinations (Sections 6.17 and 8.4.4).
Method 1669

14 July 1996

7.4.2 Ammonium Iron (II) Sulfate Solution (0.01M)—Used to prepare the chromium

(III) extraction solution (Section 7.4.3) necessary for field preservation of samples

for trivalent chromium (Section 8.4.4). Prepare the ammonium iron (II) sulfate

solution by adding 3.92 g ammonium iron (II) sulfate (ultrapure grade) to a 1 L

volumetric flask. Bring to volume with reagent water. Store in a clean polyethylene

bottle.

7.4.3 Chromium (III) extraction solution—For use when field-preserving samples for

trivalent chromium determinations (Section 8.4.4). Prepare this solution by adding

100 mL of ammonium iron (II) sulfate solution (Section 7.4.2) to a 125 mL

polyethylene bottle. Adjust pH to 8 with approximately 2 mL of ammonium

hydroxide solution. Cap and shake on a wrist-action shaker for 24 hours. This iron

(III) hydroxide solution is stable for 30 days.

7.4.4 Hydrochloric acid—High-purity, 10% solution, shipped with sampling kit in

fluoropolymer wash bottles for cleaning trivalent chromium sample preservation

equipment between samples.

7.4.5 Chromium stock standard solution (1000 μg/mL)—Prepared by adding 3.1 g

anhydrous chromium chloride to a 1 L flask and diluting to volume with

1% hydrochloric acid. Store in polyethylene bottle. A commercially available

standard solution may be substituted.

7.4.6 Standard chromium spike solution (1000 μg/L)—Used to spike sample aliquots

for matrix spike/matrix spike duplicate (MS/MSD) analysis and to prepare

ongoing precision and recovery standards. Prepared by spiking 1 mL of the

chromium stock standard solution (Section 7.4.5) into a 1 L flask. Dilute to

volume with 1% HCl. Store in a polyethylene bottle.

7.4.7 Ongoing precision and recovery (OPR) standard (25 μg/L)—Prepared by spiking

2.5 mL of the standard chromium spike solution (Section 7.4.6) into a 100 mL

flask. Dilute to volume with 1% HCl. One OPR is required for every 10 samples.

8.0 Sample Collection, Filtration, and Handling

8.1 Site Selection

8.1.1 Selection of a representative site for surface water sampling is based on many

factors including: study objectives, water use, point source discharges, non-point

source discharges, tributaries, changes in stream characteristics, types of stream

bed, stream depth, turbulence, and the presence of structures (bridges, dams, etc.).

When collecting samples to determine ambient levels of trace metals, the presence

of potential sources of metal contamination are of extreme importance in site

selection.

8.1.2 Ideally, the selected sampling site will exhibit a high degree of cross-sectional

homogeneity. It may be possible to use previously collected data to identify

locations for samples that are well mixed or are vertically or horizontally stratified.

Since mixing is principally governed by turbulence and water velocity, the selection

of a site immediately downstream of a riffle area will ensure good vertical mixing.

Horizontal mixing occurs in constrictions in the channel. In the absence of

turbulent areas, the selection of a site that is clear of immediate point sources, such
Method 1669

July 1996 15

as industrial effluents, is preferred for the collection of ambient water samples

(Reference 19).

8.1.3 To minimize contamination from trace metals in the atmosphere, ambient water

samples should be collected from sites that are as far as possible (e.g., at least

several hundred feet) from any metal supports, bridges, wires or poles. Similarly,

samples should be collected as far as possible from regularly or heavily traveled

roads. If it is not possible to avoid collection near roadways, it is advisable to

study traffic patterns and plan sampling events during lowest traffic flow (Reference

7).

8.1.4 The sampling activity should be planned to collect samples known or suspected to

contain the lowest concentrations of trace metals first, finishing with the samples

known or suspected to contain the highest concentrations. For example, if samples

are collected from a flowing river or stream near an industrial or municipal

discharge, the upstream sample should be collected first, the downstream sample

collected second, and the sample nearest the discharge collected last. If the

concentrations of pollutants is not known and cannot be estimated, it is necessary

to use precleaned sampling equipment at each sampling location.

8.2 Sample Collection Procedure—Before collecting ambient water samples, consideration

should be given to the type of sample to be collected, the amount of sample needed, and

the devices to be used (grab, surface, or subsurface samplers). Sufficient sample volume

should be collected to allow for necessary quality control analyses, such as matrix

spike/matrix spike duplicate analyses.

8.2.1 Four sampling procedures are described:

8.2.1.1 Section 8.2.5 describes a procedure for collecting samples directly into the

sample container. This procedure is the simplest and provides the least

potential for contamination because it requires the least amount of

equipment and handling.

8.2.1.2 Section 8.2.6 describes a procedure for using a grab sampling device to

collect samples.

8.2.1.3 Section 8.2.7 describes a procedure for depth sampling with a jar sampler.

The size of sample container used is dependent on the amount of sample

needed by the analytical laboratory.

8.2.1.4 Section 8.2.8 describes a procedure for continuous-flow sampling using a

submersible or peristaltic pump.

8.2.2 The sampling team should ideally approach the site from down current and

downwind to prevent contamination of the sample by particles sloughing off the

boat or equipment. If it is not possible to approach from both, the site should be

approached from down current if sampling from a boat or approached from

downwind if sampling on foot. When sampling from a boat, the bow of the boat

should be oriented into the current (the boat will be pointed upstream). All

sampling activity should occur from the bow.
Method 1669

16 July 1996

If the samples are being collected from a boat, it is recommended that the sampling

team create a stable workstation by arranging the cooler or shipping container as

a work table on the upwind side of the boat, covering this worktable and the

upwind gunnel with plastic wrap or a plastic tablecloth, and draping the wrap or

cloth over the gunnel. If necessary, duct tape is used to hold the wrap or cloth in

place.

8.2.3 All operations involving contact with the sample bottle and with transfer of the

sample from the sample collection device to the sample bottle (if the sample is not

directly collected in the bottle) are handled by the individual designated as "clean

hands." "Dirty hands" is responsible for all activities that do not involve direct

contact with the sample.

Although the duties of "clean hands" and "dirty hands" would appear to be a

logical separation of responsibilities, in fact, the completion of the entire protocol

may require a good deal of coordination and practice. For example, "dirty hands"

must open the box or cooler containing the sample bottle and unzip the outer bag;

clean hands must reach into the outer bag, open the inner bag, remove the bottle,

collect the sample, replace the bottle lid, put the bottle back into the inner bag, and

zip the inner bag. "Dirty hands" must close the outer bag and place it in a cooler.

To minimize unnecessary confusion, it is recommended that a third team member

be available to complete the necessary sample documentation (e.g., to document

sampling location, time, sample number, etc). Otherwise, "dirty hands" must

perform the sample documentation activity (Reference 7).

8.2.4 Extreme care must be taken during all sampling operations to minimize exposure

of the sample to human, atmospheric, and other sources of contamination. Care

must be taken to avoid breathing directly on the sample, and whenever possible,

the sample bottle should be opened, filled, and closed while submerged.

8.2.5 Manual collection of surface samples directly into the sample bottle.

8.2.5.1 At the site, all sampling personnel must put on clean gloves (Section 6.7)

before commencing sample collection activity, with "clean hands" donning

shoulder-length gloves. If samples are to be analyzed for mercury, the

sampling team must also put their precleaned wind suits on at this time.

Note that "clean hands" should put on the shoulder-length polyethylene

gloves (Section 6.7.1) and both "clean hands" and "dirty hands" should put

on the PVC gloves (Section 6.7.2).

8.2.5.2 "Dirty hands" must open the cooler or storage container, remove the

double-bagged sample bottle from storage, and unzip the outer bag.

8.2.5.3 Next, "clean hands" opens the inside bag containing the sample bottle,

removes the bottle, and reseals the inside bag. "Dirty hands" then reseals

the outer bag.

8.2.5.4 "Clean hands" unscrews the cap and, while holding the cap upside down,

discards the dilute acid solution from the bottle into a carboy for wastes

(Section 6.16) or discards the reagent water directly into the water body.
Method 1669

July 1996 17

8.2.5.5 "Clean hands" then submerges the sample bottle, and allows the bottle to

partially fill with sample. "Clean hands" screws the cap on the bottle, shakes

the bottle several times, and empties the rinsate away from the site. After

two more rinsings, "clean hands" holds the bottle under water and allows

bottle to fill with sample. After the bottle has filled (i.e., when no more

bubbles appear), and while the bottle is still inverted so that the mouth of

the bottle is underwater, "clean hands" replaces the cap of the bottle. In this

way, the sample has never contacted the air.

8.2.5.6 Once the bottle lid has been replaced, "dirty hands" reopens the outer

plastic bag, and "clean hands" opens the inside bag, places the bottle inside

it, and zips the inner bag.

8.2.5.7 "Dirty hands" zips the outer bag.

8.2.5.8 Documentation—After each sample is collected, the sample number is

documented in the sampling log, and any unusual observations concerning

the sample and the sampling are documented.

8.2.5.9 If the sample is to be analyzed for dissolved metals, it is filtered in

accordance with the procedure described in Section 8.3.

8.2.6 Sample collection with grab sampling device—The following steps detail sample

collection using the grab sampling device shown in Figure 1 and described in

Section 6.4.1. The procedure is indicative of the "clean hands/dirty hands"

technique that must be used with alternative grab sampling devices such as that

shown in Figure 2 and described in Section 6.4.2. 

8.2.6.1 The sampling team puts on gloves (and wind suits, if applicable). Ideally,

a sample bottle will have been preattached to the sampling device in the

class 100 clean room at the laboratory. If it is necessary to attach a bottle

to the device in the field, "clean hands" performs this operation, described

in Section 6.4.2, inside the field-portable glove bag (Section 6.6).

8.2.6.2 "Dirty hands" removes the sampling device from its storage container and

opens the outer polyethylene bag.

8.2.6.3 "Clean hands" opens the inside polyethylene bag and removes the sampling

device.

8.2.6.4 "Clean hands" changes gloves.

8.2.6.5 "Dirty hands" submerges the sampling device to the desired depth and pulls

the fluoropolymer pull cord to bring the seal plate into the middle position

so that water can enter the bottle.

8.2.6.6 When the bottle is full (i.e., when no more bubbles appear), "dirty hands"

pulls the fluoropolymer cord to the final stop position to seal off the

sample and removes the sampling device from the water.

8.2.6.7 "Dirty hands" returns the sampling device to its large inner plastic bag,

"clean hands" pulls the bottle out of the collar, unscrews the bottle from the
Method 1669

18 July 1996

sealing device, and caps the bottle. "Clean hands" and "dirty hands" then

return the bottle to its double-bagged storage as described in Sections

8.2.5.6 through 8.2.5.7.

8.2.6.8 Closing mechanism—"Clean hands" removes the closing mechanism from

the body of the grab sampler, rinses the device with reagent water (Section

7.1), places it inside a new clean plastic bag, zips the bag, and places the bag

inside an outer bag held by "dirty hands." "Dirty hands" zips the outer bag

and places the double-bagged closing mechanism in the equipment storage

box.

8.2.6.9 Sampling device—"Clean hands" seals the large inside bag containing the

collar, pole, and cord and places the bag into a large outer bag held by

"dirty hands." "Dirty hands" seals the outside bag and places the doublebagged sampling device into the equipment storage box.

8.2.6.10 Documentation—After each sample is collected, the sample

number is documented in the sampling log, and any unusual

observations concerning the sample and the sampling are

documented.

8.2.6.11 If the sample is to be analyzed for dissolved metals, it is filtered in

accordance with the procedures described in Section 8.3.

8.2.7 Depth sampling using a jar sampling device (Figure 3 and Section 6.5.1) 

8.2.7.1 The sampling team puts on gloves (and wind suits, if applicable) and

handles bottles as with manual collection (Sections 8.2.5.1 through 8.2.5.4

and 8.2.5.6 through 8.2.5.7). 

8.2.7.2 "Dirty hands" removes the jar sampling device from its storage container

and opens the outer polyethylene bag.

8.2.7.3 "Clean hands" opens the inside polyethylene bag and removes the jar

sampling apparatus. Ideally, the sampling device will have been

preassembled in a class 100 clean room at the laboratory. If, however, it is

necessary to assemble the device in the field, "clean hands" must perform

this operation, described in Section 6.5.2, inside a field-portable glove bag

(Section 6.6).

8.2.7.4 While "dirty hands" is holding the jar sampling apparatus, "clean hands"

connects the pump to the to the 1/4 in. o.d. flush line.

8.2.7.5 "Dirty hands" lowers the weighted sampler to the desired depth.

8.2.7.6 "Dirty hands" turns on the pump allowing a large volume (>2 L) of water

to pass through the system. 

8.2.7.7 After stopping the pump, "dirty hands" pulls up the line, tubing, and device

and places them into either a field-portable glove bag or a large, clean

plastic bag as they emerge.
Method 1669

July 1996 19

8.2.7.8 Both "clean hands" and "dirty hands" change gloves.

8.2.7.9 Using the technique described in Sections 8.2.5.2 through 8.2.5.4, the

sampling team removes a sample bottle from storage, and "clean hands"

places the bottle into the glove bag.

8.2.7.10 "Clean hands" tips the sampling jar and dispenses the sample

through the short length of fluoropolymer tubing into the sample

bottle.

8.2.7.11 Once the bottle is filled, "clean hands" replaces the cap of the bottle,

returns the bottle to the inside polyethylene bag, and zips the bag.

"Clean hands" returns the zipped bag to the outside polyethylene

bag held by "dirty hands."

8.2.7.12 "Dirty hands" zips the outside bag. If the sample is to be analyzed

for dissolved metals, it is filtered as described in Section 8.3.

8.2.7.13 Documentation—After each sample is collected, the sample

number is documented in the sampling log, and any unusual

observations concerning the sample and the sampling are

documented.

8.2.8 Continuous-flow sampling (Figure 4 and Section 6.5.2)—The continuous-flow

sampling system uses peristaltic pump (Section 6.15) to pump sample to the boat

or to shore through the SEBS-resin or PTFE tubing.

8.2.8.1 Before putting on wind suits or gloves, the sampling team removes the bags

containing the pump (Section 6.15), SEBS-resin tubing (Section 6.15.2),

batteries (Section 6.15.4), gloves (Section 6.7), plastic wrap (Section 6.9),

wind suits (Section 6.12), and, if samples are to be filtered, the filtration

apparatus (Section 6.14) from the coolers or storage containers in which

they are packed.

8.2.8.2 "Clean hands" and "dirty hands" put on the wind suits and PVC gloves

(Section 6.7.2).

8.2.8.3 "Dirty hands" removes the pump from its storage bag, and opens the bag

containing the SEBS-resin tubing.

8.2.8.4 "Clean hands" installs the tubing while "dirty hands" holds the pump.

"Clean hands" immerses the inlet end of the tubing in the sample stream.

8.2.8.5 Both "clean hands" and "dirty hands" change gloves. "Clean hands" also

puts on shoulder length polyethylene gloves (Section 6.7.1).

8.2.8.6 "Dirty hands" turns the pump on and allows the pump to run for

5-10 minutes or longer to purge the pump and tubing.

8.2.8.7 If the sample is to be filtered, "clean hands" installs the filter at the end of

the tubing, and "dirty hands" sets up the filter holder on the gunwale as

shown in Figure 4.
Method 1669

20 July 1996

NOTE: The filtration apparatus is not attached until immediately before sampling to prevent buildup of particulates

from clogging the filter.

8.2.8.8 The sample is collected by rinsing the sample bottle and cap three times and

collecting the sample from the flowing stream.

8.2.8.9 Documentation—After each sample is collected, the sample number is

documented in the sampling log, and any unusual observations concerning

the sample and the sampling are documented.

8.3 Sample Filtration—The filtration procedure described below is used for samples collected

using the manual (Section 8.2.5), grab (Section 8.2.6), or jar (Section 8.2.7) collection

systems (Reference 7). In-line filtration using the continuous-flow approach is described

in Section 8.2.8.7. Because of the risk of contamination, it is recommended that samples

for mercury be shipped unfiltered by overnight courier and filtered when received at the

laboratory.

8.3.1 Set up the filtration system inside the glove bag, using the shortest piece of pump

tubing as is practicable. Place the peristaltic pump immediately outside of the

glove bag and poke a small hole in the glove bag for passage of the tubing. Also,

attach a short length of tubing to the outlet of the capsule filter.

8.3.2 "Clean hands" removes the water sample from the inner storage bag using the

technique described in Sections 8.2.5.2 through 8.2.5.4 and places the sample inside

the glove bag. "Clean hands" also places two clean empty sample bottles, a bottle

containing reagent water, and a bottle for waste in the glove bag.

8.3.3 "Clean hands" removes the lid of the reagent water bottle and places the end of the

pump tubing in the bottle.

8.3.4 "Dirty hands" starts the pump and passes approximately 200 mL of reagent water

through the tubing and filter into the waste bottle. "Clean hands" then moves the

outlet tubing to a clean bottle and collects the remaining reagent water as a blank.

"Dirty hands" stops the pump.

8.3.5 "Clean hands" removes the lid of the sample bottle and places the intake end of the

tubing in the bottle.

8.3.6 "Dirty hands" starts the pump and passes approximately 50 mL through the tubing

and filter into the remaining clean sample bottle and then stops the pump. "Clean

hands" uses the filtrate to rinse the bottle, discards the waste sample, and returns

the outlet tube to the sample bottle.

8.3.7 "Dirty hands" starts the pump and the remaining sample is processed through the

filter and collected in the sample bottle. If preservation is required, the sample is

acidified at this point (Section 8.4).

8.3.8 "Clean hands" replaces the lid on the bottle, returns the bottle to the inside bag,

and zips the bag. "Clean hands" then places the zipped bag into the outer bag held

by "dirty hands."
Method 1669

July 1996 21

8.3.9 "Dirty hands" zips the outer bag, and places the double-bagged sample bottle into

a clean, ice-filled cooler for immediate shipment to the laboratory.

NOTE: It is not advisable to reclean and reuse filters. The difficulty and risk associated with failing to properly clean

these devices far outweighs the cost of purchasing a new filter.

8.4 Preservation

8.4.1 Field preservation is not necessary for dissolved metals, except for trivalent and

hexavalent chromium, provided that the sample is preserved in the laboratory and

allowed to stand for at least two days to allow the metals adsorbed to the container

walls to redissolve. Field preservation is advised for hexavalent chromium in order

to provide sample stability for up to 30 days. Mercury samples should be shipped

by overnight courier and preserved when received at the laboratory.

8.4.2 If field preservation is required, preservation must be performed in the glove bag

or in a designated clean area, with gloved hands, as rapidly as possible to preclude

particulates from contaminating the sample. For preservation of trivalent

chromium, the glove bag or designated clean area must be large enough to

accommodate the vacuum filtration apparatus (Section 6.17.3), and an area should

be available for setting up the wrist-action shaker (Section 6.17.5). It is also

advisable to set up a work area that contains a "clean" cooler for storage of clean

equipment, a "dirty" cooler for storage of "dirty" equipment, and a third cooler to

store samples for shipment to the laboratory.

8.4.3 Preservation of aliquots for metals other than trivalent and hexavalent

chromium—Using a disposable, precleaned, plastic pipet, add 5 mL of a 10%

solution of ultrapure nitric acid in reagent water per liter of sample. This will be

sufficient to preserve a neutral sample to pH <2.

8.4.4 Preservation of aliquots for trivalent chromium (References 8-9).

8.4.4.1 Decant 100 mL of the sample into a clean polyethylene bottle.

8.4.4.2 Clean an Eppendorf pipet by pipeting 1 mL of 10% HCl (Section (7.4.4)

followed by 1 mL of reagent water into an acid waste container. Use the

rinsed pipet to add 1 mL of chromium (III) extraction solution (Section

7.4.3) to each sample and blank.

8.4.4.3 Cap each bottle tightly, place in a clean polyethylene bag, and shake on a

wrist action shaker (Section 6.17.5) for one hour.

8.4.4.4 Vacuum-filter the precipitate through a 0.4 μm pretreated filter membrane

(Section 6.17.2), using fluoropolymer forceps (Section 6.17.1) to handle the

membrane, and a 47 mm vacuum filtration apparatus with a precleaned

filter holder (Section 6.17.3). After all sample has filtered, rinse the inside

of the filter holder with approximately 15 mL of reagent water.

8.4.4.5 Using the fluoropolymer forceps, fold the membrane in half and then in

quarters, taking care to avoid touching the side containing the filtrate to any

surface. (Folding is done while the membrane is sitting on the filter holder

and allows easy placement of the membrane into the sample vial). Transfer
Method 1669

22 July 1996

the filter to a 30 mL fluoropolymer vial. If the fluoropolymer vial was not

pre-equipped with the ultrapure nitric acid (Section 7.4.1), rinse the pipet

by drawing and discharging 1 mL of 10% HCl followed by 1 mL of reagent

water into a waste container, and add 1 mL of ultrapure nitric acid to the

sample vial.

8.4.4.6 Cap the vial and double-bag it for shipment to the laboratory.

8.4.4.7 Repeat Steps 8.4.4.4-8.4.4.6 for each sample, rinsing the fluoropolymer

forceps and the pipet with 10% high-purity HCl followed by reagent water

between samples.

8.4.5 Preservation of aliquots for hexavalent chromium (Reference 20).

8.4.5.1 Decant 125 mL of sample into a clean polyethylene bottle.

8.4.5.2 Prepare an Eppendorf pipet by pipeting 1 mL of 10% HCl (Section 7.4.4)

followed by 1 mL of reagent water into an acid waste container. Use the

rinsed pipet to add 1 mL NaOH to each 125 mL sample and blank aliquot.

8.4.5.3 Cap the vial(s) and double-bag for shipment to the laboratory.

9.0 Quality Assurance/Quality Control

9.1 The sampling team shall employ a strict quality assurance/ quality control (QA/QC)

program. The minimum requirements of this program include the collection of equipment

blanks, field blanks, and field replicates. It is also desirable to include blind QC samples

as part of the program. If samples will be processed for trivalent chromium

determinations, the sampling team shall also prepare method blank, OPR, and MS/MSD

samples as described in Section 9.6.

9.2 The sampling team is permitted to modify the sampling techniques described in this

method to improve performance or reduce sampling costs, provided that reliable analyses

of samples are obtained and that samples and blanks are not contaminated. Each time a

modification is made to the procedures, the sampling team is required to demonstrate that

the modification does not result in contamination of field and equipment blanks. The

requirements for modification are given in Sections 9.3 and 9.4. Because the acceptability

of a modification is based on the results obtained with the modification, the sampling team

must work with an analytical laboratory capable of making trace metals determinations to

demonstrate equivalence.

9.3 Equipment Blanks

9.3.1 Before using any sampling equipment at a given site, the laboratory or equipment

cleaning contractor is required to generate equipment blanks to demonstrate that

the equipment is free from contamination. Two types of equipment blanks are

required: bottle blanks and sampling equipment blanks.

9.3.2 Equipment blanks must be run on all equipment that will be used in the field. If,

for example, samples are to be collected using both a grab sampling device and the

jar sampling device, then an equipment blank must be run on both pieces of

equipment.
Method 1669

July 1996 23

9.3.3 Equipment blanks are generated in the laboratory or at the equipment cleaning

contractor's facility by processing reagent water through the equipment using the

same procedures that are used in the field (Section 8.0). Therefore, the "clean

hands/dirty hands" technique used during field sampling should be followed when

preparing equipment blanks at the laboratory or cleaning facility. In addition,

training programs must require must require sampling personnel to collect a clean

equipment blank before performing on-site field activities.

9.3.4 Detailed procedures for collecting equipment blanks are given in the analytical

methods referenced in Table 1.

9.3.5 The equipment blank must be analyzed using the procedures detailed in the

referenced analytical method (see Table 1). If any metal(s) of interest or any

potentially interfering substance is detected in the equipment blank at the minimum

level specified in the referenced method, the source of contamination/interference

must be identified and removed. The equipment must be demonstrated to be free

from the metal(s) of interest before the equipment may be used in the field.

9.4 Field Blank

9.4.1 To demonstrate that sample contamination has not occurred during field sampling

and sample processing, at least one field blank must be generated for every 10

samples that are collected at a given site. Field blanks are collected before sample

collection.

9.4.2 Field blanks are generated by filling a large carboy or other appropriate container

with reagent water (Section 7.1) in the laboratory, transporting the filled container

to the sampling site, processing the water through each of the sample processing

steps and equipment (e.g., tubing, sampling devices, filters, etc.) that will be used

in the field, collecting the field blank in one of the sample bottles, and shipping the

bottle to the laboratory for analysis in accordance with the method(s) referenced

in Table 1. For example, manual grab sampler field blanks are collected by directly

submerging a sample bottle into the water, filling the bottle, and capping.

Subsurface sampler field blanks are collected by immersing the tubing into the

water and pumping water into a sample container.

9.4.3 Filter the field blanks using the procedures described in Section 8.3.

9.4.4 If it is necessary to acid clean the sampling equipment between samples (Section

10.0), a field blank should be collected after the cleaning procedures but before the

next sample is collected.

9.4.5 If trivalent chromium aliquots are processed, a separate field blank must be

collected and processed through the sample preparation steps given in

Sections 8.4.4.1 through 8.4.4.6.

9.5 Field Duplicate

9.5.1 To assess the precision of the field sampling and analytical processes, at least one

field duplicate sample must be collected for every 10 samples that are collected at

a given site.
Method 1669

24 July 1996

9.5.2 The field duplicate is collected either by splitting a larger volume into two aliquots

in the glove box, by using a sampler with dual inlets that allows simultaneous

collection of two samples, or by collecting two samples in rapid succession.

9.5.3 Field duplicates for dissolved metals determinations must be processed using the

procedures in Section 8.3. Field duplicates for trivalent chromium must be

processed through the sample preparation steps given in Sections 8.4.4.1 through

8.4.4.6.

9.6 Additional QC for Collection of Trivalent Chromium Aliquots

9.6.1 Method blank—The sampling team must prepare one method blank for every ten

or fewer field samples. Each method blank is prepared using the steps in Sections

8.4.4.1 through 8.4.4.6 on a 100 mL aliquot of reagent water (Section 7.1). Do not

use the procedures in Section 8.3 to process the method blank through the 0.45 μm

filter (Section 6.14.1), even if samples are being collected for dissolved metals

determinations.

9.6.2 Ongoing precision and recovery (OPR)—The sampling team must prepare one

OPR for every ten or fewer field samples. The OPR is prepared using the steps in

Sections 8.4.4.1 through 8.4.4.6 on the OPR standard (Section 7.4.7). Do not use

the procedures in Section 8.3 to process the OPR through the 0.45 μm filter

(Section 6.14.1), even if samples are being collected for dissolved metals

determinations.

9.6.3 MS/MSD—The sampling team must prepare one MS and one MSD for every ten

or fewer field samples.

9.6.3.1 If, through historical data, the background concentration of the sample can

be estimated, the MS and MSD samples should be spiked at a level of one

to five times the background concentration.

9.6.3.2 For samples in which the background concentration is unknown, the MS

and MSD samples should be spiked at a concentration of 25 μg/L.

9.6.3.3 Prepare the matrix spike sample by spiking a 100-mL aliquot of sample

with 2.5 mL of the standard chromium spike solution (Section 7.4.6), and

processing the MS through the steps in Sections 8.4.4.1 through 8.4.4.6.

9.6.3.4 Prepare the matrix spike duplicate sample by spiking a second 100-mL

aliquot of the same sample with 2.5 mL of the standard chromium spike

solution, and processing the MSD through the steps in Sections 8.4.4.1

through 8.4.4.6.

9.6.3.5 If field samples are collected for dissolved metals determinations, it is

necessary to process an MS and an MSD through the 0.45 μm filter as

described in Section 8.3.

10.0 Recleaning the Apparatus Between Samples

10.1 Sampling activity should be planned so that samples known or suspected to contain the

lowest concentrations of trace metals are collected first with the samples known or
Method 1669

July 1996 25

suspected to contain the highest concentrations of trace metals collected last. In this

manner, cleaning of the sampling equipment between samples in unnecessary. If it is not

possible to plan sampling activity in this manner, dedicated sampling equipment should be

provided for each sampling event.

10.2 If samples are collected from adjacent sites (e.g., immediately upstream or downstream),

rinsing of the sampling Apparatus with water that is to be sampled should be sufficient.

10.3 If it is necessary to cross a gradient (i.e., going from a high-concentration sample to a lowconcentration sample), such as might occur when collecting at a second site, the following

procedure may be used to clean the sampling equipment between samples:

10.3.1 In the glove bag, and using the "clean hands/dirty hands" procedure in

Section 8.2.5, process the dilute nitric acid solution (Section 7.2) through the

Apparatus.

10.3.2 Dump the spent dilute acid in the waste carboy or in the waterbody away from the

sampling point.

10.3.3 Process 1 L of reagent water through the Apparatus to rinse the equipment and

discard the spent water.

10.3.4 Collect a field blank as described in Section 9.4.

10.3.5 Rinse the Apparatus with copious amounts of the ambient water sample and

proceed with sample collection.

10.4 Procedures for recleaning trivalent chromium preservation equipment between samples

are described in Section 8.4.4.

11.0 Method Performance

Samples were collected in the Great Lakes during September–October 1994 using the

procedures in this sampling method.

12.0 Pollution Prevention

12.1 The only materials used in this method that could be considered pollutants are the acids

used in the cleaning of the Apparatus, the boat, and related materials. These acids are used

in dilute solutions in small amounts and pose little threat to the environment when

managed properly.

12.2 Cleaning solutions containing acids should be prepared in volumes consistent with use to

minimize the disposal of excessive volumes of acid.

12.3 To the extent possible, the Apparatus used to collect samples should be cleaned and

reused to minimize the generation of solid waste.

13.0 Waste Management

13.1 It is the sampling team's responsibility to comply with all federal, state, and local

regulations governing waste management, particularly the discharge regulations, hazardous
Method 1669

26 July 1996

waste identification rules, and land disposal restrictions; and to protect the air, water, and

land by minimizing and controlling all releases from field operations.

13.2 For further information on waste management, consult The Waste Management Manual for

Laboratory Personnel and Less is Better—Laboratory Chemical Management for Waste Reduction, available from

the American Chemical Society's Department of Government Relations and Science

Policy, 1155 16th Street NW, Washington, DC 20036.

14.0 References

1. Adeloju, S.B. and Bond, A.M. "Influence of Laboratory Environment on the Precision and

Accuracy of Trace Element Analysis," Anal. Chem. 1985, 57, 1728. 

2. Berman, S.S. and Yeats, P.A. "Sampling of Seawater for Trace Metals," CRC Reviews in

Analytical Chemistry 1985, 16.

3. Bloom, N.S. "Ultra-Clean Sampling, Storage, and Analytical Strategies for the Accurate

Determination of Trace Metals in Natural Waters." Presented at the 16th Annual EPA

Conference on the Analysis of Pollutants in the Environment, Norfolk, VA, May 5, 1993.

4. Bruland, K.W. "Trace Elements in Seawater," Chemical Oceanography 1983, 8, 157. 

5. Nriagu, J.O., Larson, G., Wong, H.K.T., and Azcue, J.M. "A Protocol for Minimizing

Contamination in the Analysis of Trace Metals in Great Lakes Waters," J. Great Lakes Research

1993, 19, 175. 

6. Patterson, C.C. and Settle, D.M. "Accuracy in Trace Analysis," in National Bureau of Standards

Special Publication 422; LaFleur, P.D., Ed., U.S. Government Printing Office, Washington, DC,

1976. 

7. "A Protocol for the Collection and Processing of Surface-Water Samples for Subsequent

Determination of Trace Elements, Nutrients, and Major Ions in Filtered Water"; Office of

Water Quality Technical Memorandum 94.09, Office of Water Quality, Water Resources

Division, U.S. Geological Survey, Reston, VA, Jan. 28, 1994.

8. Standard Operating Procedure No. 4-54, Revision 01, SOP for Concentration and Analysis of

Chromium Species in Whole Seawater; Prepared by Battelle Ocean Sciences, Duxbury, MA for the

U.S. Environmental Protection Agency Office of Marine Environmental Protection, Ocean

Incineration Research Program, 1987.

9. Cranston, R.E. and Murray, J.W. "The Determination of Chromium Species in Natural

Waters," Anal. Chem. Acta 1978, 99, 275.

10. Prothro, M.G. "Office of Water Policy and Technical Guidance on Interpretation and

Implementation of Aquatic Life Metals Criteria"; EPA Memorandum to Regional Water

Management and Environmental Services Division Directors, Oct. 1, 1993.

11. "Format for Method Documentation"; Distributed by the EPA Environmental

Monitoring Management Council, Washington, DC, Nov. 18, 1993.

12. Windom, H.L., Byrd, J.T., Smith, R.G., Jr., and Huan, F. "Inadequacy of NASQAN Data

for Assessing Metal Trends in the Nation's Rivers," Environ. Sci. Technol. 1991, 25, 1137. 
Method 1669

July 1996 27

13. Zief, M. and Mitchell, J.W. "Contamination Control in Trace Metals Analysis," Chemical

Analysis 1976, 47, Chapter 6.

14. Phillips, H., Shafer, M., Dean, P., Walker, M., and Armstrong, D. "Recommendations for

Trace Metals Analysis of Natural Waters"; Wisconsin Department of Natural Resources:

Madison, WI, May 1992.

15. Hunt, C.D. In Manual of Biological and Geochemical Techniques in Coastal Areas, 2nd ed.; Lambert, C.E.

and Oviatt, C.A., Eds.; Marine Ecosystems Research Laboratory; Graduate School of

Oceanography; The University of Rhode Island: Narragansett, RI, MERL Series, Report

No. 1, Chapter IV.

16. Flegal, R. Summer 1994 San Francisco Bay Cruise, apparatus and procedures witnessed

and videotaped by W. Telliard and T. Fieldsend, Sept. 15-16, 1994.

17. Watras, C. Wisconsin DNR procedures for mercury sampling in pristine lakes in

Wisconsin, witnessed and videotaped by D. Rushneck and L. Riddick, Sept. 9-10, 1994.

18. Horowitz, A.J., Kent A.E., and Colberg, M.R. "The Effect of Membrane Filtration

Artifacts on Dissolved Trace Element Concentrations," Wat. Res. 1992, 26, 53. 

19. Engineering Support Branch Standard Operating Procedures and Quality Assurance Manual: 1986; U.S.

Environmental Protection Agency. Region IV. Environmental Services Division: Athens,

GA.

20. Grohse, P. Research Triangle Institute, Institute Drive, Building 6, Research Triangle Park,

NC.

21. Methods 1624 and 1625, 40 CFR Part 136, Appendix A.

15.0 Glossary of Definitions and Purposes

These definitions and purposes are specific to this sampling method but have been

conformed to common usage as much as possible.

15.1 Ambient Water—Waters in the natural environment (e.g., rivers, lakes, streams, and other

receiving waters), as opposed to effluent discharges.

15.2 Apparatus—The sample container and other containers, filters, filter holders, labware,

tubing, pipets, and other materials and devices used for sample collection or sample

preparation, and that will contact samples, blanks, or analytical standards.

15.3 Equipment Blank—An aliquot of reagent water that is subjected in the laboratory to all

aspects of sample collection and analysis, including contact with all sampling devices and

apparatus. The purpose of the equipment blank is to determine if the sampling devices and

apparatus for sample collection have been adequately cleaned before they are shipped to

the field site. An acceptable equipment blank must be achieved before the sampling

devices and Apparatus are used for sample collection.

15.4 Field Blank—An aliquot of reagent water that is placed in a sample container in the

laboratory, shipped to the field, and treated as a sample in all respects, including contact

with the sampling devices and exposure to sampling site conditions, filtration, storage,
Method 1669

28 July 1996

preservation, and all analytical procedures. The purpose of the field blank is to determine

whether the field or sample transporting procedures and environments have contaminated

the sample.

15.5 Field Duplicates (FD1 and FD2)—Two identical aliquots of a sample collected in separate

sample bottles at the same time and place under identical circumstances using a duel inlet

sampler or by splitting a larger aliquot and treated exactly the same throughout field and

laboratory procedures. Analyses of FD1 and FD2 give a measure of the precision

associated with sample collection, preservation, and storage, as well as with laboratory

procedures.

15.6 Matrix Spike (MS) and Matrix Spike Duplicate (MSD)—Aliquots of an environmental

sample to which known quantities of the analytes are added in the laboratory. The MS and

MSD are analyzed exactly like a sample. Their purpose is to quantify the bias and precision

caused by the sample matrix. The background concentrations of the analytes in the sample

matrix must be determined in a separate aliquot and the measured values in the MS and

MSD corrected for background concentrations.

15.7 May—This action, activity, or procedural step is optional.

15.8 May Not—This action, activity, or procedural step is prohibited.

15.9 Minimum Level (ML)—The lowest level at which the entire analytical system gives a

recognizable signal and acceptable calibration point (Reference 21).

15.10 Must—This action, activity, or procedural step is required.

15.11 Reagent Water—Water demonstrated to be free from the metal(s) of interest and

potentially interfering substances at the MDL for that metal in the referenced method or

additional method.

15.12 Should—This action, activity, or procedural step is suggested but not required.

15.13 Trace-Metal Grade—Reagents that have been demonstrated to be free from the metal(s)

of interest at the method detection limit (MDL) of the analytical method to be used for

determination of this metal(s).

The term "trace-metal grade" has been used in place of "reagent grade" or "reagent"

because acids and other materials labeled "reagent grade" have been shown to contain

concentrations of metals that will interfere in the determination of trace metals at levels

listed in Table 1.
Method 1669

July 1996 29

TABLE 1. ANALYTICAL METHODS, METALS, AND CONCENTRATION LEVELS

APPLICABLE TO METHOD 1669

Method Technique Metal MDL (μg/L) 1 ML (μg/L) 2

1631 Oxidation/Purge &

Trap/CVAFS

Mercury 0.0002 0.0005

1632 Hydride AA Arsenic 0.003 0.01

1636 Ion Chromatography Hexavalent

Chromium

0.23 0.5

1637 CC/STGFAA Cadmium 0.0075 0.02

Lead 0.036 0.1

1638 ICP/MS Antimony 0.0097 0.02

Cadmium 0.013 0.1

Copper 0.087 0.2

Lead 0.015 0.05

Nickel 0.33 1

Selenium 0.45 1

Silver 0.029 0.1

Thallium 0.0079 0.02

Zinc 0.14 0.5

1639 STGFAA Antimony 1.9 5

Cadmium 0.023 0.05

Trivalent

Chromium

0.10 0.2

Nickel 0.65 2

Selenium 0.83 2

Zinc 0.14 0.5

1640 CC/ICP/MS Cadmium 0.0024 0.01

Copper 0.024 0.1

Lead 0.0081 0.02

Nickel 0.029 0.1

1 Method Detection Limit as determined by 40 CFR Part 136, Appendix B.

2 Minimum Level (ML) calculated by multiplying laboratory-determined MDL by 3.18 and

rounding result to nearest multiple of 1, 2, 5, 10, 20, 50, etc., in accordance with procedures

used by EAD and described in the EPA Draft National Guidance for the Permitting, Monitoring, and

Enforcement of Water Quality-Based Effluent Limitations Set Below Analytical Detection/Quantitation Levels, March

22, 1994.
Method 1669

30 July 1996

TABLE 2. ANALYTES, PRESERVATION REQUIREMENTS, AND CONTAINERS

Metal Preservation Requirements Acceptable Containers

Antimony

Arsenic

Cadmium

Copper

Lead

Nickel

Selenium

Silver

Thallium

Zinc

Add 5 mL of 10% HN03 to 1-L

sample; preserve on-site or

immediately upon laboratory

receipt.

500 mL or 1 L fluoropolymer,

conventional or linear polyethylene,

polycarbonate, or polypropylene

containers with lid

Chromium

(III)

Add 1 mL chromium (III)

extraction solution to 100 mL

aliquot, vacuum filter through

0.4 μm membrane, add 1 mL

10% HN03; preserve on-site

immediately after collection.

500 mL or 1 L fluoropolymer,

conventional or linear polyethylene,

polycarbonate, or polypropylene

containers with lid

Chromium

(IV)

Add 50% NaOH; preserve

immediately after sample

collection.

500 mL or 1 L fluoropolymer,

conventional or linear polyethylene,

polycarbonate, or polypropylene

containers with lid

Mercury Total: Add 0.5% high-purity

HCl or 0.5% BrCl to pH < 2;

Total & Methyl: Add 0.5%

high-purity HCL; preserve onsite or immediately upon

laboratory receipt

Fluoropolymer or borosilicate glass

bottles with fluoropolymer or

fluoropolymer-lined caps
Method 1669

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32 July 1996
Method 1669

July 1996 33
Method 1669

34 July 1996