United States Office Of Water EPA 823-B-96-007

Environmental Protection (4305) June 1996

Agency

The Metals Translator: 

Guidance For

Calculating A Total

Recoverable Permit Limit

From A Dissolved

Criterion
i

FORWARD

This document is the result of a successful collaborative effort between the United

States Environmental Protection Agency (USEPA), Electric Power Research Institute (EPRI),

and Utility Water Act Group (UWAG). Methods and procedures suggested in this guidance

are for the specific purpose of developing the metals translator in support of the dissolved

metals criteria and should not be interpreted to constitute a change in EPA regulatory policy

as to how metals should be measured for such regulatory purposes as compliance monitoring.

This document provides guidance to EPA, States, and Tribes on how best to

implement the Clean Water Act and EPA's regulations to use dissolved metal concentrations

for the application of metals aquatic life criteria and to calculate a total recoverable permit

limit from a dissolved criterion. It also provides guidance to the public and to the regulated

community on appropriate protocols that may be used in implementing EPA’s regulations. 

The document does not, however, substitute for EPA's regulations, nor is it a regulation itself. 

Thus, it cannot impose legally-binding requirements on EPA, States, or the regulated

community, and may not apply to a particular situation based upon the circumstances. EPA

may change this guidance in the future, as appropriate.

This document will be revised to reflect ongoing peer reviews and technical advances

and to reflect the results of planned as well as ongoing studies in this technically challenging

area. Comments from users will be welcomed. Send comments to USEPA, Office of Science

and Technology, Standards and Applied Science Division (4305), 401 M Street SW,

Washington, DC 20460.

Tudor Davies, Director

Office of Science and Technology
ii

ABSTRACT

On October 1, 1993, in recognition that the dissolved fraction is a better representation of the

biologically active portion of the metal than is the total or total recoverable fraction, the Office of

Water recommended that dissolved metal concentrations be used for the application of metals aquatic

life criteria and that State water quality standards for the protection of aquatic life (with the exception

of chronic mercury criterion) be based on dissolved metals. Consequently, with few exceptions, each

metal's total recoverable-based criterion must be multiplied by a conversion factor to obtain a dissolved

criterion that should not be exceeded in the water column. The Wasteload Allocations (WLA) or Total

Maximum Daily Loads (TMDLs) must then be translated into a total recoverable metals permit limit.

By regulation (40 CFR 122.45(c)), the permit limit, in most instances, must be expressed as

total recoverable metal. This regulation exists because chemical differences between the effluent

discharge and the receiving water body are expected to result in changes in the partitioning between

dissolved and adsorbed forms of metal. As we go from total recoverable to dissolved criteria, an

additional calculation called a translator is required to answer the question "What fraction of metal in

the effluent will be dissolved in the receiving water?" Translators are not designed to consider

bioaccumulation of metals. 

This technical guidance examines what is needed in order to develop a metals translator. The

translator is the fraction of total recoverable metal in the downstream water that is dissolved; that is,

the dissolved metal concentration divided by the total recoverable metal concentration. The translator

may take one of three forms. (1) It may be assumed to be equivalent to the criteria conversion factors. 

(2) It may be developed directly as the ratio of dissolved to total recoverable metal. (3) Or it may be

developed through the use of a partition coefficient that is functionally related to the number of metal

binding sites on the adsorbent in the water column (i.e., concentrations of TSS, TOC, or humic

substances). 

Appendix A illustrates how the translator is applied in deriving permit limits for metals for

single sites and as part of a TMDL for multiple sources. Appendix B presents some indications of site

specificity in translator values. Appendix C illustrates the process of calculating the translator. 

Appendix D provides some detail of a statistical procedure to estimate sample size. Appendices E and

F present information on clean sampling and analytical techniques which the reader may elect to

follow. This material (E and F) is presented only to assist the reader by providing more detailed

discussion rather than only providing literature citations; these procedures are not prescriptive. 
iii

ACKNOWLEDGMENT

Many people have contributed long hours reviewing and editing the

many drafts of this document. The success of technical guidance documents,

such as this one, depends directly on the quality of such reviews and the quality

of the reviewers suggestions. As such, we thank the many reviewers for their

contributions. We wish to express our gratitude to the Coors Brewing

Company for making available a large and very complete data set for our use in

developing this technical guidance document; and to the City of Palo Alto,

Dept. of Public Works for permitting us to use the data they are collecting as

part of a NPDES Permit Application. The Cadmus Group, Inc. and EA

Engineering, Science and Technology, Inc also contributed to the success of

this document.

Development of this document has been a collaborative effort

between industry and the USEPA; it has been authored by Russell S.

Kinerson, Ph.D. (USEPA), Jack S. Mattice, Ph.D. (EPRI), and James

F. Stine (UWAG).
iv

TABLE OF CONTENTS

1. INTRODUCTION .......................................................... 1

1.1 Considerations of Reasonable Potential .................................... 2

1.2. Margin of Safety ..................................................... 2

1.3. Converting from Total Recoverable to Dissolved Criteria ...................... 2

1.4. Translating from a Dissolved Metal Ambient Water Quality Criterion to a Total

Recoverable Concentration in the Effluent ................................. 5

1.5. Developing Translators ................................................ 5

1.5.1. Direct Measurement of the Translator ............................... 6

1.5.2. Calculating the Translator Using the Partition Coefficient ............... 6

1.5.3. The Translator as a Rebuttable Presumption ......................... 7

1.6. Applying Metals Translators ............................................ 7

2. UNDERSTANDING THE METALS TRANSLATOR .............................. 9

2.1. Sorption-Desorption Theory ............................................ 9

2.2. The Partition Coefficient ............................................... 9

2.2.1. Developing Site Specific Partition Coefficients ....................... 10

3. FIELD STUDY DESIGN ................................................... 11

3.1. Sampling Schedule .................................................. 11

3.1.1. Considerations of Appropriate Design Flow Conditions for Metals ........ 12

3.1.2. Frequency and Duration of Sampling .............................. 12

3.2. Sampling Locations .................................................. 13

3.2.1. Collect Samples at or Beyond the Edge of the Mixing ................. 13

3.2.3. Collect Samples from Effluent and Ambient Water and Combine in the

Laboratory ................................................... 14

3.3. Number of Samples .................................................. 15

3.4 Parameters to Measure ................................................ 16

3.5. The Need for Caution in Sampling ...................................... 16

4. DATA GENERATION AND ANALYSIS ...................................... 17

4.1. Analytical Data Verification and Validation ............................... 17

4.2. Evaluation of Censored Data Sets ....................................... 17

4.3 Calculating the Translator Value . ...................................... 18

5. SITE-SPECIFIC STUDY PLAN .............................................. 20

5.1. Objective .......................................................... 20

5.2. Approach .......................................................... 20

5.3. Parameters ......................................................... 21

5.4. Sampling Stations ................................................... 21

5.5. Sampling Schedule .................................................. 22

5.6. Preparation ......................................................... 23

5.7 Sampling Procedure .................................................. 24

5.8. Field Protocol ...................................................... 25

5.9. Data Analysis ....................................................... 26
v

5.10. Schedule .......................................................... 26

5.11. State Approval ...................................................... 26

6. BUILDING A SPREADSHEET MODEL ....................................... 27

7. REFERENCES ........................................................... 29

APPENDIX A .................................................................. 31

APPENDIX B ................................................................... 40

APPENDIX C ................................................................... 42

APPENDIX D .................................................................. 51

APPENDIX E ................................................................... 52

APPENDIX F ................................................................... 58
vi

Executive Summary

his guidance presents show a functional relationship to environmental Tprocedures that may be used to properties such as TSS, pH, and salinity,

determine translator values that samples should be collected under an

more accurately reflect site specific conditions. appropriate range of conditions in order to

In this Executive Summary, steps to implement develop a statistically robust translator. If the

the dissolved metals policy through translator is not to be functionally related to

development and use of the translator are adsorbent concentrations, or other

presented. environmental parameters, the study would

Before beginning a translator study one low flow conditions where TSS concentrations

should make a determination of reasonable are relatively constant. Either the directly

potential with a translator of 1 (all the metal in determined translator (the ratio of C /C ) or a

the effluent becomes dissolved in the receiving translator calculated by using a partition

water). If the releases of metal from a coefficient (K ) may be used. 

discharge do not pose a reasonable potential of

exceeding water quality criteria levels with the The most direct procedure for

largest possible translator, then a permit limit determining a site-specific metal translator is

does not have to be written for their release. simply to determine f by measuring C and C

However, if a discharge has a water quality and to develop the dissolved fraction as the

based permit limit for a metal, and the State is ratio C /C . The translator is calculated as the

adopting standards based on dissolved metals, geometric mean of the dissolved fractions. 

then a translator study is needed. 

In the toxicity tests to derive metal as a function of TSS and other factors such as

criteria, some fraction of the metal was pH, salinity, etc. The partition coefficient is

dissolved and some fraction was bound to the ratio of the particulate-sorbed and dissolved

particulate matter. Assuming that the dissolved metal species multiplied by the adsorbent

fraction more closely approximates the concentration. Use of the partition coefficient

biologically available fraction than does total may provide advantages over the dissolved

recoverable, conversion factors have been fraction when using dynamic simulation for

calculated. The conversion factors are Waste Load Allocation (WLA) or the Total

predictions of how different the criteria would Maximum Daily Load (TMDL) calculations

be if they had been based on measurements of and permit limit determinations because K

the dissolved concentrations. allows for greater mechanistic representation of

The translator is the fraction of total variables have on f .

recoverable metal in the downstream water that

is dissolved; fD D = C /CT. It may be determined

directly by measurements of dissolved and total

recoverable metal concentrations in water

samples taken from the well mixed effluent and

receiving water (i.e., at or below the edge of

the mixing zone). EPA encourages that site

specific data be generated to develop site

specific translators.

If the translator is being developed to

normally be designed to collect samples under

D T

P

D T D

D T

A partition coefficient may be derived

P

the effects that changing environmental

D
1

1. INTRODUCTION

he U.S. Environmental dissolved metal. EPA will also approve a State TProtection Agency (EPA) risk management decision to adopt standards

issued a policy memorandum based on total recoverable metal, if those

on October 1, 1993, entitled Office of Water standards are otherwise approvable as a matter

Policy and Technical Guidance on of law.

Interpretation and Implementation of Aquatic

Life Metals Criteria ("Metals Policy"). The The adoption of the Metals Policy did 1

Metals Policy states: not change the Agency's position that the

It is now the policy of the Office of Water that under Section 304(a) of the Clean Water Act

the use of dissolved metal to set and measure continue to be scientifically defensible. When

compliance with water quality standards is the developing and adopting its own standards, a

recommended approach, because dissolved State, in making its risk management decision,

metal more closely approximates the may wish to consider sediment, food chain

bioavailable fraction of metal in the water effects and other fate-related issues and decide

column than does total recoverable metal. to adopt total recoverable or dissolved metals

The primary mechanism for toxicity to

organisms that live in the water column is by Because EPA's Section 304(a) criteria

adsorption to or uptake across the gills; this are expressed as total recoverable metal, to

physiological process requires metal to be in a express the criteria as dissolved, application of

dissolved form. This is not to say that a conversion factor is necessary to account for

particulate metal is nontoxic, only that the particulate metal present in the laboratory

particulate metal appears to exhibit toxicity tests used to develop the total

substantially less toxicity than does dissolved recoverable criteria. 

metal. Dissolved metal is operationally defined

as that which passes through a 0.45 μm or a By regulation (40 CFR 122.45(c)), the

0.40 μm filter and particulate metal is permit limit, in most instances, must be

operationally defined as total recoverable metal expressed as total recoverable metal. Because

minus dissolved metal. Even at that, a part of chemical differences between the discharged

what is measured as dissolved is particulate effluent and the receiving water are expected to

metal that is small enough to pass through the result in changes in the partitioning between

filter, or that is adsorbed to or complexed with

organic colloids and ligands. Some or all of

this may be unavailable biologically.

The Metals Policy further states:

Until the scientific uncertainties are better

resolved, a range of different risk management

decisions can be justified. EPA recommends

that State water quality standards be based on

2

existing total recoverable criteria published

criteria.

3

 The complete October 1, 1993 memorandum 1

can be obtained from EPA's Office of Water Resource metals in the effluent, in this case, would underestimate

Center (202) 260-7786 or the Office of Water Docket. the impact on the receiving water.

 See Section 510, Federal Water Pollution 2

Control Act, Public Law 100-4, 33 U.S.C. 466 et seq.

 For example, metals in the effluent of an 3

electroplating facility that adds lime and uses clarifiers

will be a combination of solids not removed by the

clarifiers and residual dissolved metals. When the effluent

from the clarifiers, usually with a high pH level, mixes

with receiving water with a significantly lower pH level,

these solids instantly dissolve. Measuring dissolved
2

dissolved and adsorbed forms of metal, an uncertainties in establishing the TMDL and

additional calculation using what is called a shall describe the manner in which the MOS is

translator is required. This translator determined and incorporated into the TMDL. 

calculation answers the question "What fraction The MOS may be provided by leaving a portion

of metal in the effluent will be dissolved in the of the loading capacity unallocated or by using

receiving water body?" Translators are not conservative modeling assumptions to establish

designed to consider bioaccumulation of WLAs and LAs. If a portion of the loading

metals. capacity is left unallocated to provide a MOS,

1.1 Considerations of Reasonable

Potential

Water quality-based permit limitations percentile translator value to address MOS

are imposed when a discharge presents a needs and account for variabliity of data and to

reasonable potential to cause or contribute to a use the critical 10 and 90 percentiles for

violation of the applicable water quality other variables such as hardness and TSS when

standard. . If the releases of metal from a conducting steady-state modeling.

facility are sufficiently low so as to pose no

reasonable potential of exceeding water quality

criteria levels, then a permit limit does not have

to be written for their release. If a facility has a

water quality based permit limit for a metal,

and the State is adopting standards based on In the toxicity tests used to develop

dissolved metals, then a translator is needed to metals criteria for aquatic life, some fraction of

produce a permit limit expressed as total the metal is dissolved and some fraction is

recoverable metal. Of course, if the facility has bound to particulate matter. When the toxicity

a technology based permit limit for the metal tests were originally conducted, metal

and the limit is more stringent than a limitation concentrations were expressed as total. Some

necessary to meet water quality standards, then of the tests were repeated and some test

no translator is required or appropriate. conditions were simulated, for the purpose of

1.2. Margin of Safety

TMDLs must ensure attainment of than does total recoverable, these conversion

applicable water quality standards, including all factors have the effect of reducing the water

numeric and narrative criteria. TMDLs include quality criteria concentrations. The conversion

waste load allocations (WLAs) for point factors are predictions of how different the

sources and load allocations (LAs) for nonpoint criteria would be if they had been based on

sources, including natural background, such measurements of the dissolved concentrations

that the sum of these allocations is not greater in all of the toxicity tests that were most

than the loading capacity of the water for the important in the derivation of the criteria.

pollutant(s) addressed by the TMDL, minus the

sum of a specified margin of safety (MOS) and Consequently each metal's total

any capacity reserved for future growth. The recoverable criterion must be multiplied by a

MOS shall be sufficient to account for technical conversion factor to obtain a dissolved criterion

the amount left unallocated shall be described. 

If conservative modeling assumptions are relied

on to provide a MOS, the specific assumptions

providing the MOS shall be identified. For

example, a State may recommend using the 90 th

th th

1.3. Converting from Total Recoverable

to Dissolved Criteria

determining the percent of total recoverable

metal that is dissolved. Working from the

premise that the dissolved fraction more closely

approximates the biologically available fraction
3

that should not be exceeded in the water

column. For example, the silver acute For additional details on aquatic life

conversion factor of 0.85 is a weighted average criteria for metals, the reader is referred to FR

and is used as a prediction of how much the 60(86): 22229-22237.

final acute value would change if dissolved had

been measured. At a hardness of 100 mg/L as

calcium carbonate (CaCO ) , the acute total 3

recoverable criterion is 4.06 μg/L while the

dissolved silver criterion is 3.45 μg/L. 

Both freshwater (acute and chronic)

and saltwater (acute) conversion factors are 4

presented (Tables 1 and 2); conversion factors

for saltwater chronic criteria are not currently

available. Where possible, these conversion

factors are given to three decimal places as they

are intermediate values in the calculation of

dissolved criteria. Most freshwater aquatic life

criteria are hardness-dependent as are the 5

conversion factors for Cd and Pb. The values

shown in these tables are with a hardness of

100 mg/L. Conversion factors (CF) for any

hardness can be calculated using the following

equations:

Cadmium

Acute:

CF = 1.136672 - [ln (hardness) (0.041838)]

Chronic:

CF = 1.101672 - [ln (hardness) (0.041838)]

Lead

Acute and Chronic:

CF = 1.46203 - [ln(hardness) (0.145712)]

 Federal Register / Vol. 60, No.86 / 22229- 4

22237 / Thursday, May 4, 1995 / Rules and Regulations. 

Water Quality Standards; Establishment of Numeric

Criteria for Priority Toxic Pollutants; States' Compliance--

Revision of Metals Criteria.

Although most of the freshwater aquatic life 5

criteria for metals are hardness dependent, those for

trivalent arsenic, trivalent chromium, mercury, aluminum,

iron, and selenium are not.
4

Table 1. Freshwater Criteria Conversion Factors for Dissolved Metals

Metal

Conversion Factors

Acute Chronic

Arsenic 1.000 1.000

Cadmium 0.944 0.909 *

Chromium (III) 0.316 0.860

Chromium (VI) 0.982 0.962

Copper 0.960 0.960

Lead 0.791 0.791 *

Mercury 0.85 N/A

Nickel 0.998 0.997

Silver 0.85 N/A

Zinc 0.978 0.986

Conversion factors fro Cd and Pb are hardness dependent. The valuse show *

are with a hardness of 100 mg/L as calcium carbonate (CaCO ). 3

Table 2. Saltwater Criteria Conversion Factors for Dissolved Metals

Metal Conversion Factors (Acute)

Arsenic 1.000

Cadmium 0.994

Chromium (III) N/A

Chromium (IV) 0.993

Copper 0.83

Lead 0.951

Mercury 0.85

Nickel 0.990

Selenium 0.998

Silver 0.85

Zinc 0.946

The fractions of metals in dissolved and particulate phases are very dependent on water
5

chemistry. Because of the (typically) great most straightforward approach is to analyze the

differences between chemical properties of mixture to determine the dissolved and total

effluents, the chemical properties of receiving recoverable metal fractions. This ratio of

waters, and the chemical properties of the dissolved to total recoverable metal

waters used in the toxicity tests, there is no concentrations can then be used to translate

reason to expect that the conversion factors can from a dissolved concentration in the water

be used to estimate either the fraction of metal column downstream of the effluent discharge

that would be in the dissolved phase in the (the criterion concentration) to the total

receiving waters or the total recoverable metal recoverable metal concentration in the effluent

concentration in the effluent that would result that will not exceed that dissolved

in a receiving water concentration not concentration in the water column. 

exceeding a criterion concentration. Thus, a

translator is required to derive a total Appendix A presents an example that

recoverable permit limit from a dissolved summarizes the steps involved in applying the

criterion . dissolved metals policy, using the translator, to 6

1.4. Translating from a Dissolved Metal

Ambient Water Quality Criterion to 1.5. Developing Translators

a Total Recoverable Concentration

in the Effluent

As the effluent mixes with the regarding development and application of the

receiving water, the chemical properties of the metals translator to go from a dissolved metal

mixture will determine the fraction of the metal criterion to a total recoverable permit limit. 

that is dissolved and the fraction of the metal This chapter identifies different approaches that

that is in particulate form (typically adsorbed to may be used in developing site specific

surfaces of other compounds). Many different translators. In the following chapters, we will

properties influence this dissolved to total focus on designing and conducting field studies,

recoverable metal ratio. Important factors analytical chemistry procedures, data analysis,

include water temperature, pH, hardness, and application of the metals translator to meet

concentrations of metal binding sites such as mass balance requirements.

concentrations of total suspended solids (TSS),

particulate organic carbon (POC), and There is always a translator in going

dissolved organic carbon (DOC), as well as from a dissolved criterion to a total recoverable

concentrations of other metals and organic permit limit. The rebuttable presumption is

compounds that compete with the metal ions that the metal is dissolved to the same extent as

for the binding sites. It is difficult to predict it was during criteria development. The default

the result of such complex chemistry. The translator value should be that the translator 

develop a permit limit.

The purpose of this technical guidance

document is to present additional details

equals the conversion factor, this represents a

reasonable worst case. 

EPA encourages that site specific data

be generated to develop site specific partition

coefficients (translators), and use of translators

based on EPA's old data (as published in

USEPA, 1984 and presented in Table 3 below)

As a reasonable worst case, however, it may be 6

assumed that metal in the receiving environment would be

biologically available to the same extent as during toxicity

testing; and the conversion factors may be used as

translators if a site-specific translator is not developed. In

that case, the water quality criterion that already has been

multiplied by the conversion factor would be divided by

the conversion factor.
6

be phased out unless other data as suggested conservative estimates of the translator. 

below, have been generated that establish their Similar conclusions have been arrived at with

validity for the sites in question. The guidance data from rivers and streams in Washington.

released on October 1, 1993 identified three Therefore, it may be appropriate to develop a

methods of estimating the metals translator. dissolved to total recoverable ratio based on a

One of these was the use of the relationships single sample to confirm that the partition

developed from the STORET data (USEPA, coefficient produces an estimate of the

1984). In the years between 1984 and 1993 translator that is either reasonably accurate or

there was general recognition that the conservative.

relationships had some inaccuracies due to

contaminated metals data and other factors. This guidance document presents

However, limited comparisons of predictions procedures that may be used to determine

from these relationships with data generated translator values that accurately reflect site

and analyzed with good QA/QC indicated specific conditions. 

generally good agreement and some tendency

to be conservative. The stream data for lead The procedures in this document do not

were reanalyzed and a better relationship was cover all possible approaches. Greater

developed. The parameters for these default precision can be achieved by means of more

partition coefficient estimation equations are elaborate procedures which, at the current time,

presented in Table 3 where K has units of L/kg are generally used only in research situations. P

with TSS expressed as mg/L. Although, the use of such procedures is

Table 3. Calculation of Default Partition document. 

Coefficients [K = K • TSS ] P PO

Lakes Streams

Metal KPO KPO

Cu 2.85E+06 -0.9000 1.04E+06 -0.7436

Zn 3.34E+06 -0.6788 1.25E+06 -0.7038 dissolved water quality criterion to a total

Pb 2.0E+06 -0.5337 2.80E+06 -0.8

Cr(III 2.17E+06 -0.2662 3.36E+06 -0.9304 fractions. The translator is the fraction of total

)

Cd 3.52E+06 -0.9246 4.00E+06 -1.1307

Ni 2.21E+06 -0.7578 4.90E+05 -0.5719

Site specific conditions may render

these default partition coefficients, overly or

underly protective. Data presented in Appendix

B illustrate the variability that exists between

different sites in some values of the dissolved

metal fractions. Recent work by Sung (1995)

demonstrates that reliance on the relationships

in Table 3 does not always provide for

7

acceptable, they will not be discussed in this

1.5.1. Direct Measurement of the

Translator

As mentioned in Section 1.4, the most

straightforward approach for translating from a

recoverable effluent concentration is to analyze

directly the dissolved and total recoverable

recoverable metal that is dissolved and may be

determined directly by measurements of

dissolved and total recoverable metal

concentrations in water samples.

1.5.2. Calculating the Translator Using the

Partition Coefficient

Personal communication with Gregory 7

Pelletier, Department of Ecology, Olympia, WA (206)-

407-6485.
7

The partition coefficient (K P) may be options are unavailable. There are some

derived as a function of the number of metal advantages to its use including the fact that it is

binding sites associated with the adsorbent. already being used by some States, it is easy to

USEPA (1984) and the technical support explain and implement, and it effectively

accompanying EPA's Dissolved Policy implements the statutory requirement found in 

Memorandum expressed the translator §303(d) of the Clean Water Act calling for a

according to Eqn 2.7. The role of TSS is margin of safety (MOS) in developing TMDLs. 

evident from this equation; as TSS increases, The disadvantage is that, as demonstrated by

the dissolved fraction decreases because of the the conversion factors used to convert total

increased number of binding sites. recoverable water quality criteria into the

There is a general tendency to assume will remain totally in the dissolved form, even

that the partition coefficient will increase with in high quality water. Furthermore, when the

increasing TSS. It is important to recognize assumption that all of the metal is dissolved is

that in both the laboratory and in the field, K P applied in combination with dissolved criteria

has been observed to be constant or to decrease conversion factors, the resulting permit limit is

with increasing particulate concentrations (Di more restrictive than that which existed when

Toro, 1985). metal criteria were expressed as total

The fraction of the total metal in the presumption, conversion factors can be used as

downstream water that is dissolved (the the translator where no site-specific translator

translator) may be determined indirectly by is developed; this is the reasonable worst case .

means of a partition coefficient. The partition

coefficient, in turn, may be either a function of

varying adsorbent concentrations or be related

to a constant adsorbent concentration associated

with critical flow conditions. See Section 3.1.1

for considerations of factors affecting the If the translator is to be a function of

appropriate design flow for metals. adsorbent concentrations (e.g.,TSS) it is critical

1.5.3. The Translator as a Rebuttable

Presumption

In the Technical Support Document for samples under low flow conditions where TSS

Water Quality-based Toxics Control (EPA, concentrations are relatively constant. Either

1991a) commonly called the TSD, as well as in the directly determined ratio (C /C ) or a

other documents, EPA has discussed the translator calculated using a partition

options one has for translators. These options coefficient (K ) may be used. 

include using a translator which assumes no

difference between dissolved and total In actuality, metal partitioning in

recoverable metal concentrations. The TSD receiving water bodies is more complicated

identifies this as the most stringent approach

and suggests it would be appropriate in waters

with low solids concentrations, situations where

the discharged form of the metal was mostly in

the dissolved phase, or where data to use other

dissolved form, it is highly unlikely that metals

recoverable. Therefore, as a rebuttable

8

1.6. Applying Metals Translators

that samples be collected under a broad range

of TSS conditions to develop a statistically

robust translator. If the translator is not to be

functionally related to adsorbent concentrations

the study would normally be designed to collect

D T

P

Using the conversion factors as a translator will 8

produce the same result as assuming no difference

between dissolved and total recoverable metal

concentrations.
8

than can be explained by TSS alone. 

Consequently, it is possible and permissible to

develop the translator on some basis other than

TSS, such as humic substances or POC. The 9

materials presented in Appendix C guide the

reader through a possible evaluation of other

factors that might be warranted in some studies.

Basically, the translator is applied by

dividing a dissolved WLA or permit limitation

by the translator to produce a total recoverable

permit limitation. Appendix A contains a

detailed explanation of how permit limits can

be derived.

If the adsorbent is POC, then K (L/mg) = C 9

P P

(μg/L ) / (CD (μg/L) • POC (mg/L)
9

2. UNDERSTANDING THE METALS

TRANSLATOR

he translator is the fraction of Tthe total recoverable metal in The metal concentrations are typically

the downstream water that is expressed as mass per volume (i.e., C

dissolved. The reason for using a metal (mass/vol water), C (mass/vol solids plus

translator is to allow calculation of a total water, the bulk volume)). 

recoverable permit limit from a dissolved

criterion. For a given adsorbent concentration

A translator is used to estimate the

concentration of total recoverable metal in the C = x • m [Eqn 2.2]

effluent discharge that equates to (or results in)

the criterion concentration in the receiving where x is the metal concentration of the

water body. In this chapter we will explore particulate phase expressed on a dry weight

some of the possible approaches to developing solids basis (e.g., μg/mg) and m is the

site specific metals translators. The purpose of adsorbent concentration (mass of solids/vol of

this document is to help implement EPA’s solids and water; e.g., mg/L). With these

dissolved metals policy; therefore, every dimensions, C has units of μg/L.

attempt has been made to keep the following

discussion as technically simple as possible. 

As you read this discussion, keep in mind that

the metals partition between dissolved and

adsorbed forms. The partition coefficient

expresses this equilibrium relationship and may The distribution of metal at equilibrium

be used to calculate the dissolved fraction. The between the particulate and dissolved forms is

following discussion presents only the essential the partition coefficient K (L/mg). The

equations needed to develop the translator. For partition coefficient is the slope of the data of

a comprehensive discussion of partition particulate metal (μg/mg) against dissolved

coefficients, see Thomann and Mueller (1987). metal (μg/L)

2.1. Sorption-Desorption Theory

In effluents and receiving waters, provides other useful relationships between

metals can exist in either of two basic phases; dissolved and particulate metals concentrations

adsorbed to particulates or dissolved in water. 

More precisely, these "particulates" are C = C • K • m [Eqn 2.4]

sorbents including clays and related minerals,

humic substances, organic and inorganic

ligands, and iron and sulfur compounds. The Substituting Eqn 2.4 into Eqn. 2.1 gives

total concentration of a metal in the water

column can be expressed as

CT = C + C P D [Eqn 2.1] C = (C • K • m) + C

where C = total metal, T

CP = particulate sorbed metal, and

CD = dissolved metal.

D

P

(e.g., TSS) C can be expressed as P

P

P

2.2. The Partition Coefficient and the

Dissolved Fraction

P

K = x / C [Eqn. 2.3] P D

Combining Eqn. 2.3 with Eqn 2.2

P D P

CT = C + C P D

T D P D
10

C = C (K • m + 1) [Eqn 2.5] dissolved metal (C ). T D P

The translator, or dissolved metal fraction, f D, K = x / C

is defined as

fD = CD / C [Eqn. 2.6] let m = TSS, then x = C / TSS. T

Substituting Eqn 2.6 into Eqn 2.5 and solving

for fD gives

fD = (1 + K • m) [Eqn. 2.7] P

-1

The distribution of metal between dissolved

and adsorbed phases therefore depends on the K = C / (C •TSS ) [Eqn. 2.9]

partition coefficient and the adsorbent

concentration. This is the basis of the metals

translator.

2.2.1. Developing Site Specific Partition

Coefficients

As we saw in Eqn. 2.3, the partition

coefficient is not measured directly, rather it is

calculated from measured values (at

equilibrium) of adsorbed metal per unit

adsorbent (x) divided by the concentration of 10

D

P D

We also saw in Eqn. 2.2 that CP = x • m. If we

P

Substituting into Eqn 2.3 gives

K = (C / TSS ) / C [Eqn. 2.8] P P D

which rearranges to 11

P P D

TSS is used throughout this document as the 10

measure of metal binding sites. It is possible to use other

measures of the binding sites such as total organic carbon

(TOC), particulate organic carbon (POC), dissolved modified by the conversion factor of 10 kg/mg:

organic carbon (DOC), or some combination of TSS, TOC, K (L/kg) = C (μg/L ) / (C (μg/L) • TSS (mg/L)

DOC, etc. • 10 (kg/mg)) 

 If K is desired with units of L/kg, Eqn 2.9 is 11

P

-6

P P D

-6
11

3. FIELD STUDY DESIGN

onsideration should be given to in the watershed, photosynthetic activity in the Cuse of clean sampling and water body (lowest pH at dawn and highest pH

analytical techniques. These in early afternoon coincident with peak

are recommended but not necessarily required; photosynthetic activity of phytoplankton and

however, it is essential that appropriate other aquatic vegetation), or effluent discharge

procedures be used to detect metals at the to the water body. Changes in pH over a

concentrations present in the effluent and specific range may have a marked effect on

receiving waters. Clean sampling and metal solubility. Consequently, it may be

analytical methods are useful ways of obtaining important to consider the normal range of pH

good data when traditional methods may when designing the study and to collect

provide data with significantly high or low bias. samples under pH conditions that would render

Sufficient quality control data must accompany the metal or metals of interest most soluble, or

environmental data to allow its validation. over a narrow range of pH conditions to reduce 12

A statistically valid field study design, is of concern in geographic areas that have little

with attendant QA/QC, (e.g., adequate number buffering capacity and on “acid sensitive”

of samples, field blanks, spiked samples, etc.) streams.

is essential for the successful development of a

metals translator. Recognizing that a key factor Industrial and municipal waste waters

in metals availability to biota in the water and receiving waters vary greatly in chemical

column is the partitioning of metals between constituents and characteristics. This chapter

the solid phase material and water, TSS (which presents general guidelines and considerations

contains humic materials, clay minerals, other to assist in establishing effective sampling

organic matter both living and dead) emerges programs for varied situations. 

as the obvious environmental variable of

interest. However, the composition of TSS is

highly variable both in terms of the constituents

(e.g., sand, silt, clay, planktonic organisms, and

decomposing organic materials) and their size The sampling design should be

distributions. Highly variable relationships adequate to evaluate spatial and/or temporal

between TSS and metals partitioning must be variability and to properly characterize the

anticipated because of the temporal (e.g., environmental condition. The choice of when

season of year, type and magnitude of storm) and where to conduct the study, how long to

and the spatial variability (e.g., such as may be study, and how frequently to sample may be

associated with changes in hydrology, influenced by the type of translator being

geochemistry, or presence, number, and type of developed. 

effluent dischargers) of the receiving water

bodies. For example, pH may vary over

several units as a result of acidic precipitation

scatter in the resulting data set. The pH effect

3.1. Sampling Schedule

For instance, the translator may be

developed specifically for use under conditions

that are most likely to be representative of

"critical flow" or "design" conditions. (The

critical flow may or may not be the same as the

7Q10 or 4B3 design low flow; this is discussed

in Section 3.1.1 below.) To meet this

application, samples should be collected under

Measurements made below the quantitation 12

levels (QL) will suffer from significant analytical

variability, which may directly affect the ratio (especially

if the ratio in near 1.0). Test measurements capable of

achieving extremely low detection levels and QLs should

be sought to avoid the excessive analytical variability. 

The choice of laboratories and analytical methods can be

critical to the success of a translator study.
12

conditions that approximate the critical flow. For instance, consider a facility that has

 On the other hand, the translator may fraction of the receiving water flow. It may be

be developed for use over a broad range of flow that TSS concentrations in the mixing zone

and associated TSS concentrations. If this is show a bimodal distribution with stream flow

desired, then the samples should be collected to (high under low flow conditions because of the

produce a data set representative of a broad effluent dominance, low under higher stream

range of conditions. flow conditions because of greater dilution, and

3.1.1. Considerations of Appropriate

Design Flow Conditions for Metals

In the absence of data to the contrary, Additionally, pH may vary throughout the day,

the normal assumption will be that low flow may vary seasonally, or may be somehow

(limited dilution capacity) is the critical flow correlated with flow. Information of this nature

for metals. However, determining the period should also be used in selecting the most 13

of critical flow is more complicated for metals appropriate conditions and most appropriate

than for many other pollutants because one time to conduct the study. To reduce

cannot necessarily ascertain the appropriate variability in the data caused by factors other

design conditions without a field study to than adsorbent concentration, it will be helpful

generate data on flow, pH, and adsorbent to measure pH and, to the extent possible,

concentrations. If one were to collect samples collect samples under similar pH conditions. 

of TSS, POC, water flow, hardness pH, As suggested above, samples should be

ambient metals, etc. over a prolonged period collected under pH conditions that would

(i.e., several years) then one could examine the render the metal(s) of interest most soluble.

data set to determine which combination of

conditions would result in the highest dissolved

metal concentration for a "unit load" of metal

in the effluent stream. The flow regime

associated with this critical condition would A field study to develop a metals

constitute the design flow. Because the translator is expected to extend over several

dissolved metals concentration in the receiving months. A long sampling schedule has many

water depends on metals partitioning to solids advantages, chief among them is the ability to

as well as dilution of dissolved metals in the generate data that are representative of the

water, and because the lowest TSS (or other many conditions that characterize receiving

adsorbent) concentrations do not always water bodies. Ideally, prior to collecting data

correspond with low stream flow conditions, to develop a metals translator, the receiving

there will be some combination of TSS, flow, water body would have been studied

hardness and pH that will result in the greatest sufficiently to characterize temporally, if not

dissolved concentration. spatially, distributions of flow, TSS, hardness,

high solids releases and contributes a sizeable

high under high flow conditions because of

upstream nonpoint source solids loadings). It is

conceivable that the low TSS may be more

important than low flow in achieving water

quality standards in this stream segment. 

3.1.2. Frequency and Duration of Sampling

and pH. To the extent that such data exist, the

sampling can be stratified to reduce variability. 

If such data are available to characterize the

system, statistical methods may be used to

determine the frequency of sampling. In the

absence of such data, EPA suggests weekly or

It is important to recognize that worse-case 13

acute dilution (highest concentration of effluent) may not

occur during periods of low flow and TSS, especially in

estuarine waters. Under such circumstances, the data to

develop the translator should be collected to represent the

critical conditions.
13

biweekly sampling during specified receiving zone, the CMC applies at the end of the pipe. 

water flow conditions when developing the The criteria chronic concentration (CCC)

translator for use under "design flow" applies at all points outside the CCC mixing

conditions and biweekly or monthly sampling zone.

when developing the translator for use over a

range of flow conditions. There are some practical difficulties

In addition to receiving water the receiving environment. In the absence of a

conditions, it is equally important to consider mixing zone study it is very difficult to define

variable plant operations when determining with any certainty the shape and extent of a

sampling frequency. In addition to continuous mixing zone, or the dilution and dispersion that

and uniform releases, the range of conditions occur within the mixing zone. Many states

may include: have separate boundaries for compliance with

(1) Seasonal operation, dispersion processes are influenced not only by

(2) Less than 24 hour per day volume, velocity, and other characteristics of

operation, the discharge, but also by convection, currents,

(3) Special times during the day, week and wind effects in the receiving water. As a

or month, or result, extensive sampling and computer

(4) Any combination of the above. modeling are typically required to estimate the

When monitoring these types of

operations, it is necessary to sample during The following approaches are 

normal working shifts in the season of acceptable for the purpose of developing the

productive operations. translator. When deciding where to locate

3.2. Sampling Locations

Depending on state guidance or constitute a basis for concern that downstream

regulatory negotiations, samples may be conditions may result in nontoxic metal

collected from the effluent, the receiving water becoming toxic.

before mixing with the effluent, the receiving

water at the edge of the mixing zone, and/or the

receiving water in the far field (beyond the

mixing zone). Results obtained from these

different locations may differ substantially. 

The magnitude of the translator may collected at or beyond the edge of the mixing

depend on the concentration of effluent in the zone. Appropriate field sampling techniques

downstream water. The concentration of and appropriate QA/QC are discussed in

effluent in the downstream water will depend Appendix E. It is important to recognize that if

on where the sample is taken, which will not be samples are not also collected from the ambient

the same for acute and chronic mixing zones. water (background), then the subsequent

The criteria maximum concentration (CMC) analysis (for permit limit determination)

applies at all points except those inside a CMC implicitly assumes that all of the metal in the

mixing zone; thus if there is no CMC mixing receiving water comes from the discharger.

involved in selecting the sampling location in

acute and chronic criteria. Dilution and

nature and extent of mixing.

sampling stations, consideration should be

given to sampling at the point of complete

mixing (rather than at the edge of the mixing

zone) if existing environmental factors 

3.2.1. Collect Samples at or Beyond the

Edge of the Mixing Zone

 It is recommended that samples be
14

The translator should result in a permit concentrations and increased analytical

limit that is protective of the receiving water. difficulties must also be considered when

In order to ensure this, under some conditions, contemplating these studies. If, however, the

it may be important that samples be collected samples are collected within the same reach,

from a point where complete mixing has there should not be any appreciable increase in

occurred. It may be advisable within a given dilution.

river segment to take the samples well below

the edge of the mixing zone in order to ensure If samples for translators are collected

good mixing and to reduce variability in the from far-field locations a translator will result

data set. Environmental processes that might whose value is established based on the

cause nontoxic metal to become toxic include characteristics of the receiving water, not on

fate processes such as oxidation of organic the characteristics at the edge of the mixing

matter or sulfides or an effluent or tributary that zone or on the characteristics of the effluent

lowers the pH of the downstream water. The before it is fully mixed. Recent investigations

approach of collecting samples beyond the edge of discharges from a Waste Water Treatment

of the mixing zone may be especially valuable Plant (WWTP) to a lowflow stream in Florida

in estuarine and coastal ocean locations where have demonstrated an apparent increase in the

the ebb and flow of tidal cycles complicate the dissolved fraction of silver at a distance (travel

hydrodynamics. In areas where cumulative time) of four hours downstream of the 14

discharge effects can be anticipated, the discharge.

individual contributions and combined effects

of the multiple discharges must be considered

in developing the translator, as well as in the

TMDL allocation and development of the

permit limit.

3.2.2. Collect Samples from the Far Field

There are times when concerns for far water (i.e., upstream of the outfall in rivers and

field effects will require evaluation of the ratios streams; outside of the influence of the

of dissolved and total recoverable metals and discharge in lakes, reservoirs, estuaries, and

metal partitioning beyond the mixing zone. Far oceans). Appropriate QA/QC and field

field sampling is appropriate in circumstances sampling techniques are discussed in Appendix

where changes in geology, land use/land cover, E. Mixing and filtration must be done as soon

or low pH effluent discharges from other as possible to minimize risk of changes to the

facilities may alter the water body chemistry. dissolved/total metals ratio due to adsorption

Far field studies also may be required where onto the container and partitioning effects. The

spatial changes in water chemistry and Agency is soliciting data that will allow

hydrology affect sorption-desorption rates and recommendations to be developed regarding

settling rates respectively with the potential maximum delays in combining the samples and

adverse effects on the biological integrity of how long the combined sample should be

benthic communities. The potential for allowed to equilibrate before filtering an aliquot

increased dilution resulting in lower metal for the dissolved portion.

15

3.2.3. Collect Samples from Effluent and

Ambient Water and Combine in the

Laboratory

Samples are collected from the effluent

(i.e., end of pipe) and the ambient receiving

This document does not discuss hydrologic Personal communication with Tim Fitzpatrick, 14

differences that are specific to marine and estuarine Florida Department of Environmental Protection,

discharges. Tallahassee, FL.

15
15

Samples are collected from the effluent a theoretical minimum number of samples. 

and the receiving water before it mixes with the Beyond this consideration, it is necessary to be

discharge and are mixed in accordance with the cognizant of such factors as spatial and

dilution factor to create a simulated temporal variability in physical and chemical

downstream water in proportion to the dilution conditions that may affect the value of the

that the mixing zone is designed to achieve. translator and to design the study to

The mixed waters are analyzed for dissolved appropriately account for these differences. 

and total recoverable metal. The translator is Seasonality of receiving water flow and

calculated from the dissolved fractions. associated chemical properties need to be

For rivers and streams, the receiving appropriate to provide protection to the water

water samples would be collected upstream of body during the low flow or otherwise critical

the discharge. For lakes, reservoirs, estuaries, condition associated with a particular critical

and oceans, the samples would be collected at a time of the year.

point beyond the influence of the discharge, yet

representative of water that will mix with the In the metals guidance memorandum

discharge. In tidal situations, where the (Prothro, 1993), EPA recommended the

effluent plume may move in different development of site-specific chemical

directions over the tidal cycle, some knowledge translators based on the determination of

of the hydrodynamics of the receiving water dissolved-to-total ratios: EPA's initial

will be necessary to select the appropriate point recommendation was that at least four pairs of

as well as the appropriate sampling time within total recoverable and dissolved ambient metal

the tidal cycle. In estuaries that are dominated measurements be made during low flow

by either river flow or tidal flushing, the conditions or 20 pairs over all flow conditions. 

sampling location should reflect the dominant EPA suggested that the average of data

source of dilution water. collected during low flow or the 95th percentile

In cases of multiple discharges to the The low flow average provides a representative

same river segment, for example, the translator picture of conditions during the rare low flow

should be developed as fD at the downstream events. The 95th percentile highest dissolved

end of the river segment and applied to all fraction for all flows provides a critical

dischargers to that segment condition approach roughly analogous to the

3.3. Number of Samples

The collection of dissolved and total

Most statistics textbooks (e.g., concentrations at low flows is still the

Snedecor, 1956; Steel and Torrie, 1980; Zar, recommended approach, but the collection of at

1984; Gilbert, 1987)) present discussions of least 10 samples, rather than 4, is

sample size (i.e., number of samples). recommended to achieve higher confidence in

Generally, sample size is affected by the the data. The 95 percentile or other extreme

variance of the data, the allowable error in the percentile of f (e.g., 90 percentile) may be

estimation of the mean, and the desired used as an alternative method of including a

confidence level. If data have been collected MOS in TMLDs or WLAs. Additional details

previously, they can be used to provide a good of determining the required sample size are

estimate of the expected variance. presented in Appendix D.

From a statistical basis we can specify

considered. The value of the translator must be

highest dissolved fraction for all flows be used. 

approach used to identify low flows and other

critical environmental conditions.

th

D

th
16

3.4 Parameters to Measure

Ideally the field study is designed to and (2) that new guidance is needed for

generate data on total recoverable (C T), sampling and analysis that will produce reliable

dissolved (CD), and particulate metal fractions results for trace metals determinations.

(CP) as well as TSS, POC, pH, hardness, and

stream (volume) flow. A complete data set EPA has released guidance for

allows for more complete understanding of the sampling in the form of Method 1669

environmental fate and transport processes and "Sampling Ambient Water for Determination

may result in a more accurate permit limit of Trace Metals at EPA Water Quality Criteria

because of reduced variability and Levels" (USEPA, 1995a). This sampling

uncertainties. method describes the apparatus, techniques, and

Depending on the means by which the quality control necessary to assure reliable

translator is being developed, some of these sampling. Method 1669 was developed based

data elements may not need to be generated. on information from the U.S. Geological

For instance, it may be desirable to estimate Survey and researchers in academia, marine

CP= CT - CD rather than to measure CP. Of laboratories, and the commercial laboratory

course, if CP is the parameter of greatest community. A summary of salient points are

interest, calculating C from the dissolved and presented in Appendix E. Interested readers P

total recoverable concentrations incorporates may also wish to refer to the 1600 series of

the uncertainty associated with the latter two methods, CFR 40, Part 136, July 1, 1995.

measurements. A direct measurement of the

particulate fraction may reduce this uncertainty. Note that recent studies conducted by

Of course, the measurement of the particulate the USGS (Horowitz, 1996) indicate that great

fraction then increases the total uncertainty bias can be introduced into dissolved metals

because of the uncertainty associated with its determinations by filtration artifacts. The use

measurement. It is likely that if the three of the Gelman #12175 capsule filter, which has

fractions (total, dissolved, and particulate) are an effective filtration area of 600 cm , and the

measured, the sum of these three fractions will practice of limiting the volume of sample

not equal CT. It is possible to develop the passed through the filter to 1000 ml are

translator from a study that only generates data necessary to ensure unbiased collection of

on total recoverable and dissolved dissolved metals. Variations from these

concentrations in the downstream water. recommendations must be demonstrated to

3.5. The Need for Caution in Sampling

The sampling procedures for metals

that have been used routinely over the years

have recently come into question in the

academic and regulatory communities because

the concentrations of metals that have been

entered in some databases have been shown to

be the result of contamination. At EPA's

Annapolis Metals Conference in January of

1993, the consensus of opinion was (1) that

many of the historical low-concentration

ambient metals data are unreliable because of

contamination during sampling and/or analysis,

2

produce equivalent quality data.
17

4. DATA GENERATION AND

ANALYSIS

etermination of metals’ reported by laboratories and permittees Dconcentrations at ambient so that Agency reviewers can validate

criteria levels is not presently the data.

routine in many commercial and industrial

laboratories. To familiarize laboratories with The review of data collected and

the equipment and techniques that will allow reported in accordance with data

determination of metals at trace levels, the elements reported.

Agency has supplemented existing analytical

methods for determination of metals at these A Data Inspection Checklist that can be

levels, and published this information in the used to standardize procedures for

"Quality Control Supplement for Determination documenting the findings of each data

of Trace Metals at EPA Water Quality Criteria inspection.

Levels Using EPA Metals Methods" (QC

Supplement; USEPA, 1994a). The QC

Supplement is based on the procedures and

techniques used by researchers in marine

research laboratories who have been at the Frequently data sets are generated that

forefront of trace metals determinations. contain values that are lower than limits

An overview of the QC Supplement is values (i.e., quantitation levels [QL]). These

presented in Appendix E for the reader’s data points are often reported as nondetected

convenience. Persons actually developing a and are referred to as censored. The level of

metal translator should read the QC censoring is based on the confidence with

Supplement which the analytical signal can be discerned

4.1. Analytical Data Verification and

Validation

In addition to Method 1669 for Measurements made below the

sampling (USEPA, 1995a) and analytical quantitation levels will suffer from analytical

methods for determination of trace metals variability, which may directly effect the ratio,

(USEPA, 1994b), the Agency has produced especially if C /C is near 1.0. Extremely low

guidance for verification and validation of detection levels and quantitation levels should

analytical data received (USEPA, 1995b). This be sought to avoid excessive analytical

guidance was produced in response to the variability.

Agency's need to prevent unreliable trace

metals data from entering Agency databases This guidance does not address whether

and other databases in the environmental or not it is appropriate to use test measurements

community and relies on established techniques below quantitation or detection levels in any

from the Agency's data gathering in its Water context other than chemical translator studies

and Superfund analytical programs to conducted by the discharger. For translator

rigorously assess and document the quality of studies, measurements at or above a detection

analytical data. General issues covered in the level that is reliably achievable by the

guidance include:

The data elements that must be

4.2. Evaluation of Censored Data Sets

deemed reliable enough to report as numerical

from the noise. While the concentration may

be highly uncertain for substances below the

reporting limit, it does not necessarily mean

that the concentration is zero (USEPA, 1992). 

D T
18

Box 1. The Translator is the Dissolved

Fraction: fD D = C /CT

Step 1 - For each field sample determine 

 fD D = C /CT

Step 2 - If the translator is not dependent

on TSS, determine the geometric

mean

GM_fD= exp( ln(f )/ n) 1 D

n

and upper percentile values of the

dissolved fraction. If the data are

found not to be log-normal, then

alternative transformations should

be considered to normalize the

data and determine the

transformed mean and percentiles. 

Also, alternative upper percentiles

may be adopted as a state’s policy

to address MOS (e.g., 90 or 95 th th

percentiles may be appropriate.)

Step 3 - If the translator is found to be

dependent on TSS, regression

equations relating f D to TSS should

be developed. Appropriate

transformations should be used to

meet the normality assumptions

for regression analysis (for

example log-transformation of f D

and TSS may be appropriate). The

regression equation or an upper

prediction interval may be

considered for estimation of f D

from TSS depending on the

strategy for addressing MOS.

particular laboratory performing the analyses

can be used. If concentrations are near the

detection level, some of the samples may be

reported as below the detection level (i.e.,

nondetects). If both total recoverable and

dissolved concentrations are nondetects, the

data pair should be discarded. If only the

dissolved concentration is nondetect, it could be

assumed to equal one-half the detection level. 

Some studies have collected enough data so

that incomplete records, including records

where dissolved concentrations were

nondetects, were discarded prior to analysis. If,

for example, the translator is a function of TSS,

the TSS concentration that accompanies each

total recoverable and dissolved data pair must

also be at or above the detection level. 

Alternatively, assuming that an adequate

number of samples have been collected,

incomplete records may be eliminated from

analysis.

4.3 Calculating the Translator Value

The most direct procedure for

determining a site-specific metal translator is

simply to determine f D by measuring CT and CD

and to develop the dissolved fraction as the

ratio CD/CT. The first step (Box 1) is to

calculate the dissolved fraction in the receiving

water. The translator is calculated as the

geometric mean of the dissolved fractions. 

As a general comment on the proposed

use of the geometric mean, the geometric mean

is only an appropriate estimate of the central

tendency if the data are log-normal. 

Alternative measures of central tendency or

transformations should be considered if the

distribution of fD is found not to be log-normal. 

For example, the arcsine square root

transformation is often used to normalize

populations of percentages or proportions
19

Box 2. The Translator is the

Dissolved Fraction (fD)

Calculated via Site Specific

Partition Coefficients

Step 1 - For each field sample

determine 

C = C - C , P T D

K = C /(C • TSS) P P D

Step 2 - Fit least squares regressions to

data (transformed, stratified by

pH, etc.) as appropriate to solve

for K .P

Step 3 - Substitute the regression

derived value of K in Eqn 2.7, P

fD = (1 + K • TSS) P

-1

Step 4 Determine fD for a TSS value

representative of critical

conditions.

(square root of each value is transformed to its have on f .

arcsine).

A partition coefficient may be derived determine appropriate translator values are

as a function of TSS and other factors such as presented in Appendix C.

pH, salinity, etc. (Box 2). The partition

coefficient is the ratio of the particulate-sorbed

and dissolved metal species multiplied by the

adsorbent concentration. The dissolved

fraction and the partition coefficient are related

as shown in step 3. 

The partition coefficient may provide

advantages over the dissolved fraction when

using dynamic simulation for Waste Load

Allocation (WLA) or the Total Maximum

Daily Load (TMDL) calculations and permit

limit determinations because K allows for P

greater mechanistic representation of the

effects that changing environmental variables

D

Examples of these analyses to
20

5. SITE-SPECIFIC STUDY PLAN

hapter 3 discusses the to any type of receiving water. Where Cconsiderations involved in differences in the study plan would occur for

designing a field study for a different receiving waters, the considerations

site-specific chemical translator for metals. are highlighted with a . Dischargers on runChapter 4 and Appendix D discuss analytical of-river reservoirs, or on lakes or reservoirs

chemistry considerations. This Chapter dominated by riverain discharges during runoff

provides guidance on preparing a basic study events, should generally follow the

plan for implementing a translator study, with considerations listed for rivers/streams.

specific considerations for each of four types of

receiving waters: rivers or streams, lakes or

reservoirs, estuaries, and oceans. It can be used

for all of the options discussed in this guidance. 

This generic plan is based on the determination State the objective of the project. For

of dissolved-to-total ratios in a series of 10 or example, 

more samples. With this guidance, the

discharger should be able to prepare a study "To determine the acute [or

plan that its environmental staff could chronic or acute and chronic]

implement or one that could be used to solicit metals translator for [list

bids from outside consultants to conduct the metals] in the discharge from

studies. In most cases, the study plan should be Outfall 00X."

submitted to the state for review and approval

before implementation.

The format of this chapter is to present

sequentially the essential sections of a study Describe briefly the approach adopted

plan: objective, approach, parameters, in the study plan to achieve the objective. For

sampling stations, sampling schedule, example, 

preparation, sampling procedure, field protocol,

and data analysis. Within each section a three- "Samples of effluent and

tiered format is used to provide instructions for upstream receiving water will

the study plan preparer. The basic directions be collected and mixed in

for preparing the section are presented left- proportions appropriate to the

justified on the page. Under each direction is a dilution at the edge of the

checklist of decisions or selections, designated [acute/chronic] mixing zone[s]. 

with the symbol , that the preparer must make These mixed samples will be

to complete that direction. Under each of these analyzed for total recoverable

decision points is a list of important and dissolved [list metals]. The

considerations, noted by the symbol . translator will be calculated as

References to more detailed discussions are the geometric mean of the

provided where appropriate. If any state ratios of dissolved metal to

guidance for translator studies exists, it would total recoverable metal for all

supersede any of the considerations discussed sample pairs."

below unless the state and the discharger agree

to an alternative plan. Equipment blanks and field blanks are

Much of the basic study plan is

presented in a generic context that is applicable

5.1. Objective

5.2. Approach

critical to document sample quality,
21

especially at low concentrations which can be be necessary to achieve detection levels

significantly biased by even small amounts of low enough to produce a valid

contaminants. Field duplicate samples are also translator. Such alternatives include

very important to establish precision in matrix modifiers, backgroundsampling and final sample preparation. correction instrumentation, and

5.3. Parameters

analyses. Preliminary testing and

Prepare a table listing parameters, detection level studies may be

analytical methods, and required detection necessary to determine if a problem

levels. exists.

Select parameters—see Section 3.4. As an option for justifying the selected

Select analytical methods and detection agency, prepare a narrative of the rationale for

levels—see Section 4. the selections made.

Detection level will be the primary Identify the laboratory that will be

determinant of the analytical methods analyzing the samples and provide evidence of

to be used. Metals potentially requiring state certification, if required.

GFAA and perhaps ultralow analyses

are those with very low aquatic life Describe laboratory protocols and QA

criteria and concentrations below 10 requirements.

g/L. Prime candidates are cadmium

(fresh water), copper (salt water), Select standard or clean (class-100)

mercury, and silver. practices—see Section 3.1, 4.3.

Ideally, the detection level should be 5- Select QA requirements 

10 times lower than the concentration

of dissolved metal. An ultralow Trip blank

detection level should be considered if Duplicate analysis of all samples and

dissolved concentrations are less than blanks

1-2 times higher than the standard Laboratory method blank for each

detection level. batch of samples

Detection levels and methods should be

reviewed with the analytical laboratory

expected to perform the analyses before

finalizing the study plan. One or more

test samples may be advisable if Prepare a map and/or a narrative

detection levels or concentrations are description of the sampling stations.

unknown in any particular matrix.

Estuary/Ocean Chloride interference

may affect detection levels, particularly

for GFAA methods. Special steps may

extraction or preconcentration. If

uncertain, check with a local laboratory

experienced in saltwater matrix

methods and detection levels to the regulatory

MS/MSD on each batch of samples

5.4. Sampling Stations

Select a sample location option—see

Sections 3.2, 3.2.1, 3.2.2, 3.2.3.

Conceptually, collecting samples at the
22

edge of the mixing zone is the Determine whether grab or composite

most direct way to determine samples will be used —see Appendix

the translator. However, the E.

edge of the mixing zone may

be difficult to define, especially Wastewater treatment plant

if stream flow and discharge effluent—24-hour composite

rate (e.g., number of units Noncontact cooling water—same as

operating) will be variable over receiving water

the course of the study. Even if

the mixing zone's dimensions

are prescribed exactly, the

samples may have to be

collected at some critical

hydrologic condition to

represent the critical

toxicological conditions. An

alternative option may be to

collect effluent and upstream

receiving water samples, and

mix them in the appropriate

proportions before analysis. In

addition, far-field sampling

may be required to establish

that dissolved metal

concentrations do not increase

after the effluent is well-mixed

with the receiving water.

Definition of the "upstream" sampling

point will vary with the receiving water

type:

River/Stream Immediately upstream

of the influence of the discharge, or any

point further upstream with no

contributing source between it and the

outfall

Lake/Reservoir Beyond the influence

of the discharge (dilution > 100:1),

generally in a direction toward the

headwaters of the lake/reservoir if

possible

Estuary/Ocean Beyond the influence

of the discharge (dilution > 100:1),

generally in a direction away from the

movement of the discharge plume at

the time of sampling

River/Stream—Grab, under low-flow

conditions

Lake/reservoir—Grab

Estuary/Ocean—Grab (slack tide) for

acute; tidal composite for chronic

5.5. Sampling Schedule

Specify the number of samples,

frequency of sampling, study period, and any

other conditions (e.g., season, stream flow)

affecting the sampling schedule.

Select the number of samples—see

Section 3.3.

The recommended minimum number

of samples for a low-flow sampling

program is 10; 12 would be appropriate

if monthly sampling for a year is

desired to incorporate seasonality.

If sampling occurs over a wide range of

flows or the translator is developed

through regression analyses, 20 or more

samples may be appropriate. 

Select the frequency of sampling—see

Section 3.1.2.

Weekly sampling is recommended;

monthly sampling may be appropriate

if seasonality is expected to be an issue.

River/Stream The interval between

samples will have to be somewhat

flexible because samples should be

collected under low-flow conditions;

e.g., if a sample is to be collected on

Wednesday and the river flow is high
23

on that day, sampling should be collected during periods of typical

postponed until the first day operation, particularly with respect to

when flow returns to base-flow operations that affect the TSS

levels, or it will have to be concentration or the concentration or

postponed until the next the total:dissolved ratio of the metal(s)

planned weekly event. being studied.

Estuary/Ocean Monthly or biweekly

sampling may be required if state

regulations reference critical monthly

tidal periods, such as biweekly neap

tides.

Determine the study period—see conducted under base-flow conditions,

Section 3.1. which could be defined in terms of

River/Stream Generally, the low-flow

period of the year (e.g., July through

October in the East and Midwest) is

preferred, unless the time constraints of

the permitting process or the local

hydrologic regimen dictate otherwise.

Lake/Reservoir Unless there are

seasonal discharges or reservoir

operating procedures that significantly

affect water quality, study period

generally is not critical to study plan. 

Algal bloom conditions should be

avoided.

Estuary May need to split sampling

between low- and high-salinity seasons,

because large changes in salinity

between seasons indicates the

dominance of different water sources

(fresh water at low salinity and salt

water at high salinity) with potentially

different particulate matter

concentrations or binding capacities.

Ocean Unless seasonal currents

significantly affect water quality, study

period generally is not critical to study

plan.

Determine other important

considerations

Plant operating conditions should be

considered. Samples should be

If copper is being studied by an electric

utility, and the plant has copper and

non-copper condenser tubes, sampling

should occur when the units with

copper tubing are operating.

River/stream Sampling should be

measured stream flow (e.g., less than

the 25th percentile low flow), stream

stage (e.g., stream height less than 1.5

feet at gaging station XYZ), turbidity

(e.g., less than 5 NTU), TSS

concentration (e.g., less than 10 mg/L),

visual appearance (e.g., no visible

turbidity), or days since last significant

rainfall (e.g., more than 3 days since

rainfall of 0.2 inches or more).

Lake/Reservoir As long as the

sampling location is unaffected by

runoff, hydrologic considerations are

not significant.

Estuary/Ocean Since acute criteria

are generally considered to have an

exposure duration of 1 hour, samples

for acute translators should be collected

under worst-case tidal

conditions—generally low slack when

dilution is typically at its lowest. 

Chronic criteria are usually expressed

with a 4-day average exposure

duration, so sampling over a tidal cycle

is appropriate for chronic translators. If

the discharger is willing to accept the

conservatism of sampling for a chronic

translator under worst-case

conditions—slack tide—then sampling

costs could be reduced substantially. 

5.6. Preparation 
24

Prepare a list of equipment and supplies Prepare a list of contacts and phone

that need to be assembled before each sampling numbers.

event; for example,

Sample bottles, labeled, with

preservative (for total recoverable)

Samples bottles, labeled, without correct procedure for collecting a sample at any

preservative (for dissolved station.

Sample bottle carrier, e.g., clean plastic Start with guidance on the careful

cooler sampling techniques necessary to avoid sample

Waterproof marker for filling in bottle

labels 1. Given the low metals concentrations

Chain-of-custody form taken to ensure that samples are not

Sampling gear—e.g., sampling bottle, Smoking or eating is not permitted

sampling pole (plastic or aluminum if while on station, at any time when

aluminum is not being studied), high- sample bottles are being handled, or

speed peristaltic pump and teflon during filtration.

tubing

Field portable glove box (for on-site wear clean clothing, i.e., free of dirt,

filtering and compositing) grease, etc. that could contaminate

Plastic gloves (non-talc) sampling apparatus or sample bottles.

Filtering apparatus, if required for field 3. An equipment blank should be done

crew with the actual equipment used for the

Field notebook or log sheet blank described in this section should

Safety equipment equipment BEFORE the environmental

Describe cleaning requirements for serve to verify equipment and sampling

sample bottles and sampling equipment that protocol cleanliness.

will come in contact with samples.

Select standard or clean apparatus or sample bottles should wear

sampling/analysis. the sampling gloves provided. One

Prepare a list of actions to be bottles, and that person should touch

completed before the sampling event, such as nothing else while collecting or

contacts to be made (discharger, consultant, transferring samples.

laboratory, regulatory agency).

5.7 Sampling Procedure

Prepare detailed instructions on the

contamination. For example,

expected, extreme care needs to be

contaminated during sample collection. 

2. Each person on the field crew should

environmental samples. The field

be performed with the sampling

samples are collected. This blank will

4. Each person handling sampling

person only should handle sample

Then provide step-by-step instructions
25

for the sampling crew to follow. The specific Are hydrologic conditions (e.g., base

steps will vary depending on what type of flow, slack tide) acceptable?

water/wastewater is being sampled and what

type of sampling device is being used. For grab Describe in clear, simple instructions

samples collected by hand using a sampling the sequence of actions that the field crew will

pole to which the sample bottles are attached, follow from the beginning to end of a sampling

the guidance might continue: event. This sequence will vary from project to

5. Attach unpreserved bottle to sample

collecting pole. Plunge pole 2 to 3 feet 1. Before embarking, confirm number and

under water surface quickly. Pull type (preserved/unpreserved) of sample

sample bottle up and fill preserved bottles, and read off checklist of

bottle from unpreserved sample bottle, equipment/supplies.

leaving 1⁄2 to 1 inch of air space at the

top. Swirl to mix acid, close cap 2. Before beginning sampling, fill in

tightly, and return bottle to carrier. chain-of-custody forms and bottle

6. Collect duplicate sample by plunging of sampling.

unpreserved sample bottle back under

water, retrieving, and capping bottle Each bottle should have a unique

tightly for dissolved sample, again sample number, and it should be

leaving 1⁄2 to 1 inch of air space in the labeled "Total" or "Dissolved." If

bottle. Return bottle to carrier. preservative has been added to the

Other sampling procedures may be should note that fact.

chosen to produce acceptable quality data, e.g. Chain-of-custody forms pre-prepared

a closed sampling system with immediate with everything but the sampling date

sample processing. Equipment for in-line and time are recommended.

sample collection used for filtering with the Provide sample chain-of-custody form

(essentially mandatory) Gelman capsule filter and bottle label as attachments to study

can be used for sample collection. See Method plan.

1669 § 8.2.8 for a description of sampling steps

and Method 1669 § 8.3 for on-site composting 3. At Station 1, fill in sampling time on

and filtration in a glove box. See also label of two samples bottles, one

Appendix E.2. preserved and one unpreserved. 

5.8. Field Protocol

Provide a list of criteria which the field form—weather, hydrologic conditions,

crew leader should review before starting plant operating status (if known),

sampling to ensure that proper conditions exist. sample bottle numbers and collection

Is there a discharge? Are operating observations or circumstances.

conditions at the facility appropriate for

measuring the metals of concern in the 4. At Station 2, fill in sampling time on

effluent? labels of two sample bottles, one

project. Typical steps might include:

labels with all information except time

bottles before sampling, the label

Collect samples following the

procedure outline above. Return bottles

to carrier immediately after collection. 

Fill in field notebook or log

time (total and dissolved), and unusual
26

preserved and one unpreserved. automatic samplers, field filtering, and

Collect samples following the overnight shipping of samples. Because data

procedure outline above. quality is directly dependent on quality control,

Return bottles to carrier the Quality Control Supplement( EPA, 1994a)

immediately after collection. should be reviewed.

Fill in field notebook or log

form—weather, hydrologic

conditions, plant operating

status (if known), sample bottle

numbers and collection time Describe the method for calculating the

(total and dissolved), and chemical translator.

unusual observations or

circumstances. Select a calculation procedure—see

5. After finishing at Station 2, collect the Specify the treatment for values below

field blanks—one preserved and one the detection level—see Section 4.2.

unpreserved. Fill in sampling time on

label, open sample bottle, and pour in

laboratory water. Cap bottles tightly

and place in carrier. Note bottle

numbers and collection time in field Provide a schedule for the entire study,

notebook or log sheet. from selection of consultant or mobilization of

If additional sampling gear is used in report.

collecting the samples, the field blanks

should be collected by rinsing that gear Link schedule to receipt of approval

three times with the laboratory water, from state, if required

and then filling the gear with enough Emphasize impact of delays on study if

water to transfer to the 2 field blank sampling must occur within a certain

bottles. If a pump or an automatic calendar timeframe

sampler is used, several sample bottle Incorporate contingencies for sampling

volumes of laboratory water should be events postponed because of

pumped through the sampler tubing unacceptable conditions

before the field blank bottles are filled.

6. Complete chain-of-custody. Check

bottle carrier to ensure bottles are

upright and well packed. Provide a signoff line for state

7. Deliver samples to laboratory. Have not mandatory.

sample custodian sign chain-of-custody

for receipt of samples, and obtain a

copy of the chain-of-custody.

Depending on the project, additional

instructions may be needed for setting up

5.9. Data Analysis

Sections 1.5.

5.10. Schedule

field effort through completion of final study

5.11. State Approval

regulatory agency. This is recommended, but
27

6. BUILDING A SPREADSHEET

MODEL

s discussed in earlier chapters, For example, with Eqn 6.1, the Aa series of steps must be taken downstream TSS concentration is estimated

to implement the dissolved from mass balance calculations of upstream

metals policy, including converting the water and effluent loadings: 

quality criteria from the total recoverable to the

dissolved form, translation from the dissolved

CCC or CMC to the total recoverable metal

concentration in the discharger’s waste stream,

calculating the WLA or TMDL, and developing

the permit limit. These steps or calculations are

easily handled using a simple spreadsheet

model. Use of these equations, whether in a

spreadsheet or not, can avoid many common

mistakes.

The following equations may be used to

translate dissolved criteria to total recoverable

permit limits with translators developed

through studies such as those described in

Chapter 5. This model may be used as a static

model with design flow conditions, it may be

used in a continuous mode (i.e.., using daily

flow and other data), or it may be used (with

programs such as @RISK or Crystal Ball ) to

perform Monte Carlo analyses. These

calculations do not provide concentration

estimates between the point of discharge and

the point of complete mixing.

The in-stream total recoverable

concentration is estimated by solving the

following equation:

C = ( Q C + Q C ) / ( Q + Q ) t u u e e u e

[Eqn 6.1]

where Ct = pollutant concentration at the

edge of the mixing zone,

Q = upstream flow, u

C = upstream pollutant u

concentration (background),

Q = effluent flow, e

C = effluent pollutant e

concentration, and

= fraction of flow available for 

mixing.

TSS = ( Q TSS + Q TSS ) / ( Q + Q ) u u e e u e

[Eqn 6.2]

For translators developed from

partitioning equations , (Eqn 2.7), the 16

dissolved in-stream concentration can be

expressed as:

C = C / (1+ K TSS) [Eqn 6.3] d t p 

By setting the dissolved in-stream

concentration (Cd) equal to the dissolved

criterion concentration (Cd d = CC ) and

rearranging the equation, we can solve for the

in-stream total recoverable concentration (C ')t

that equates to a dissolved in-stream

concentration equal to the dissolved criterion. 

Note that this corresponds to Eqn 2.5.

C ' = CC (1+K TSS) [Eqn 6.4] t d p

The total recoverable concentration in

the effluent (C ') that equates to a dissolved in- e

stream concentration which equals the

dissolved criterion in the mixed receiving

waters is calculated by Eqn 6.5. This

represents the maximum release that will still

allow attainment of water quality standards,

If the translator has been determined directly 16

from measurements of dissolved and total recoverable

metal in the downstream water, Eqns 6.3 and 6.4 are not be

used. Instead, the dissolved criterion concentration is

divided by fD to calculate Ct' which in turn is used in Eqn

6.5.

If the partition coefficient has units of L/kg, then

both Eqns 6.3 and 6.4 contain the term 1E-6.
28

that is the maximum WLA or the maximum Streamix, an EPA developed

TMDL. spreadsheet application for mixing zone

Ce' = (Ct' ( Qu

 + Qe) - Qu u C ) / Qe

[Eqn 6.5]

Table 4 presents a simple spreadsheet

that utilizes these relationships. Note that the

second equation in the spreadsheet calculates

KP and the third equation calculates the

associated fD. In studies where the translator is

developed directly as f D, the KP equation in the

spreadsheet is deleted and f D is changed from

an equation to an input parameter. 

analyses, has been enhanced to consider metal

partitioning between dissolved and particulatesorbed forms. This version, developed for

EXCEL, is called METALMIX and provides

details of mixing between the point of

discharge and the point of complete mix.

Beyond these approaches, EPA's

DYNTOX model (USEPA, 1995c) has been

modified to properly account for the

distribution of metals between dissolved and

particulate-sorbed forms. DYNTOX supports

Continuous Simulation, Monte Carlo, and

Lognormal Probabilistic Analyses

Table 4. Spreadsheet to Calculate Total Recoverable Waste Load Allocation based on Dissolved

Criterion

Variables: Input Values:

Q_u 104

TSS_u 325

C_u 19

Q_e 8.75

TSS_e 1845

Hardness_u 100

Hardness_e 50

mixing fraction (theta) 0.25

Equations:

CC_d =EXP(a*LN(Hardness_mix)+b)*conv_fact <dissolved criterion concentration>

Kp =2.8*TSS_mix^-0.8 <example only>

fD =1/(1 + Kp*TSS_mix)

Hardness_mix =(theta * Q_u * Hardness_u + Q_e * Hardness_e) / (theta * Q_u + Q_e)

TSS_mix =(theta * Q_u * TSS_u + Q_e * TSS_e) / (theta * Q_u + Q_e)

C_t_prime =CC_d*(1 / fD) <instream total recov conc that equates to dissolved criterion>

C_e_prime =(C_t_prime * (theta * Q_u + Q_e) - theta * Q_u * C_u)/ Q_e

 <effluent total recov conc resulting in the dissolved criterion in receiving water>
29

7. REFERENCES

Benedetti, M.F., Milne, C.J., Kinniburgh, D.G.,

Van Riemskijk, W.H., and Koopal, L.K. 1995. U.S. Environmental Protection Agency

Metal Ion Binding to Humic Substances: (USEPA). 1983. Methods for Chemical

Application of the Non-Ideal Competitive Analysis of Water and Wastes. EPA 600-4-79-

Adsorption Model. Environ. Sci. Technol. 020.

29,446-457.

Di Toro, D.M. 1985. A Particle Interaction (USEPA). 1984. Technical Guidance Manual

Model of Reversible Organic Chemical for Performing Waste Load Allocations - Book

Sorption. Chemosphere 14(10):1503-1538. II Streams and Rivers - Chapter 3 Toxic

Gilbert, R.O. 1987. Statistical Methods for 

Environmental Pollution Monitoring. Van U.S. Environmental Protection Agency

Nostrand Reinhold, NY. (USEPA). 1991a. Technical Support

Horowitz, A.J., Lum, K.R., Lemieux, C., Control. EPA 505-2-90-001.

Garbarino, J.R., Hall, G.E.M., Demas, C.R. 

1996. Problems Associated with Using U.S. Environmental Protection Agency

Filtration to Define Dissolved Trace Element (USEPA). 1991b. Methods for the

Concentrations in Natural Water Samples. Determination of Metals in Environmental

Environmental Science & Technology, Vol 30, Samples. EPA 600-4-91-010.

No 3.

Shi, B., Grassi, M.T., Allen, H.E., Fikslin, T.J., (USEPA). 1992. Guidelines for Exposure

and Kinerson, R.S. 1996. Development of a Assessment; Notice. Federal Register

Chemical Translator for Heavy Metals in 57(104):22888-22938.

Receiving Water. Paper Presented at Water

Environment Federation 69th Annual U.S. Environmental Protection Agency

Conference & Exposition, Dallas, TX (USEPA). 1994a. Quality Control Supplement

Snedecor, G.W. 1956. Statistical Methods. Water Quality Criteria Levels Using EPA

The Iowa State University Press, Ames, Iowa, Metals Methods. Engineering and Analysis

534pp. Division (4303), USEPA, Washington, DC

Steel, R.G.D. and Torrie, J.H. 1980. 

Principles and Procedures of Statistics, A U.S. Environmental Protection Agency

Biometrical Approach. Second Edition. (USEPA). 1994b. Methods for the

McGraw-Hill. Determination of Metals in Environmental

Sung, W. 1995. Some observations on surface

partitioning of Cd, Cu, and Zn in estuaries. U.S. Environmental Protection Agency

Environ. Sci. Technol. 29:1303-1312. (USEPA). 1995a. Method 1669, Sampling

Thomann, R.V. and Mueller, J.A. (1987) Metals at EPA Water Quality Criteria Levels. 

Principles of Surface Water Quality Modeling

and Control. HarperCollins Publishers Inc,

New York, NY,644pp.

U.S. Environmental Protection Agency

Substances. EPA 440-4-84-022.

Document for Water Quality-based Toxics

U.S. Environmental Protection Agency

for Determination of Trace Metals at EPA

20460, December 1994.

Samples. EPA 600-R-94-111.

Ambient Water for Determination of Trace
30

EPA 821-R-95034. 

U.S. Environmental Protection Agency

(USEPA). 1995b. Guidance on the

Documentation and Evaluation of Trace Metals

Data Collected for Clean Water Act

Compliance Monitoring. Engineering and

Analysis Division (4303), Washington, DC

20460, December 1994.

U.S. Environmental Protection Agency

(USEPA). 1995c. Dynamic Toxics Wasteload

Allocation Model (DYNTOX). EPA 823-C95-005. 

Zar, J.H. 1984. Biostatistical Analysis. 

Second Edition. Prentice Hall,, NJ.
WQCMetal exp a ln(H) b

31

(1)

APPENDIX A

Deriving Permit Limits for Metals

his Appendix summarizes the Tsteps involved in applying the

dissolved metals policy and

illustrates how the translator is used in

developing a permit limit. Water quality standards consist of

degradation statement. The river, in this

A.1 The Setting for the Example

Our example site is a river which has recreation (i.e., “fishable, swimmable”), and

been identified as being water quality-limited the State has adopted the federal water quality

because of high copper concentrations with criteria into its water quality standards to

potential adverse impacts on aquatic life. protect aquatic life and human health. The

Copper loading to the impaired reach comes numeric water quality criteria for acute toxicity

from naturally occurring and anthropogenic (criterion maximum concentration, or CMC)

sources in the watershed (background) and and chronic toxicity (criterion continuous

permitted point source discharges, including concentration, or CCC) to aquatic life are part

two metal plating facilities and a publicly of the water quality standards and are based on

owned treatment works (POTW). For the sake the dissolved fraction of metals. The CMC and

of simplicity, steady-state modeling is used. CCC depend on ambient hardness

Episodic, precipitation-driven runoff loadings concentrations as expressed by the following

from urban and industrial areas adjacent to the equation form (as total recoverable metal):

river could be accounted for using continuous

simulation. 

Design low flows are typically used for

calculating steady-state wasteload allocations

(WLAs), including the 1-day average low flow

with a ten year recurrence period (1Q10) for where a and b are metal-specific constants

acute criteria and the 7-day average low flow defined as part of the water quality criterion. 

with a ten-year recurrence period (7Q10) for For copper in freshwater systems, these

chronic criteria. Analysis of 30 years of constants are:

records from the USGS gage above the sources

indicates a 1Q10 flow of 111.77 cfs and a 7Q10

flow of 140.09 cfs. 

The two metal plating facilities in our

example have multiport diffusers, which have

been shown to quickly achieve complete

mixing across the width of the river. The

POTW effluent enters the same reach as the

facility discharges and is released to a bend in

the river where mixing also occurs rapidly. The

State’s water quality regulations require that

water quality criteria are met at the edge of the

mixing zone. 

A.2 Water Quality Standards and

Criteria

criteria, designated uses, and an antiexample, is classified as having designated uses

for aquatic habitat and primary contact

Copper a b

Chronic Criteria 0.8545 -1.465

(μg/L)

Acute Criteria 0.9422 -1.464

(μg/L)
32

Box A-1. Calculation of Acute (CMC)

and Chronic (CCC) WQC for Copper

Hardness (mg/L) 100

Conversion Factor 0.96

CMC(total recoverable) (μg/L) =

exp[.9422 x ln(100) - 1.464] = 17.7

CMC(dissolved)(μg/L) = 17.7 x .96 = 17.0

CCC(total recoverable)(μg/L) =

exp[.8545 x ln(100) - 1.465] = 11.8

CCC(dissolved)(μg/L) = 11.8 x .96 = 11.4

At 100 mg/L hardness, these lead to a

CCC of 11.8 μg/L and a CMC of 17.7 μg/L. 

These criteria concentrations are expressed on

the basis of total recoverable metal (Box A-1). 

A.3 Change from Total Recoverable to

Dissolved Criteria

As illustrated in Box A-1, each metal's

total recoverable criterion must be multiplied

by a conversion factor to obtain a dissolved

criterion that should not be exceeded in the

water column. The criteria are based on a total

recoverable concentration. For example, the

copper acute (and chronic) conversion factor of

0.960 is a weighted average and is used as a

prediction of how much the final value would

change if dissolved had been measured. Where can then be used to translate from a dissolved

possible, these conversion factors are given to concentration in the water column (the criterion

three decimal places as they are intermediate concentration or some fraction thereof ) to the

values in the calculation of dissolved criteria. total recoverable metal concentration in the

At a hardness of 100 mg/L, the acute dissolved effluent that will equate to that dissolved

criterion is 17.0 μg/L. Most of the freshwater concentration in the water column.

aquatic life criteria and their conversion factors

are hardness-dependent. Box A-1 shows an

example calculation of dissolved and total

recoverable copper criteria concentrations.

A.4 Translating from a Dissolved Metal

Ambient Criterion to a Total

Recoverable Concentration in the

Effluent

As the effluent mixes with the recoverable copper in the river at low flow

receiving water, the chemical properties of the (upstream of the effluent discharge) is 4 μg/L

mixture will determine the fraction of the metal and varies within a relatively small range, from

that is dissolved and the fraction of the metal less than 2 to 9.5 μg/L, with the average

that is in particulate form (typically adsorbed to declining to about 3 μg/L above median flows. 

surfaces of other compounds). The most direct For this analysis the mean background

approach to determining the fraction of the total concentration is used.

recoverable metal in the downstream water that

is dissolved (fD)is to analyze the downstream The (instream) total recoverable

water (the mixing zone of effluent and concentration [C ] that equates to the

receiving water) to determine the dissolved and dissolved criterion concentration is expressed

total recoverable metal fractions. This ratio as:

A.5 Calculation of WLAs for a Point

Source

For this example, it is assumed that the

site-specific data have been collected and

analyzed to determine that fD = 0.4. 

From analysis of existing data, the

average background concentration of total

instream
[Cinstream] WQC(dissolved)

1

fD

WLA(total metal)

[Cinstream] (Qe Qs) QsCs

Qe

WLAa

42.5 (50 111.77) 111.77 4

50

128.6 μg/L total recoverable Cu

33

(2)

 (3)

(4)

Box A-2. Data for Calculation of WLAs

and Existing Permit Limits for the POTW

Effluent Flow (cfs) 50

Average Effluent Concentration,

as Total Recoverable Copper (μg/L) 81

Coefficient of Variation of Load 0.12

Given the information on the design other words, the full assimilative capacity of

flows and background concentrations (Box A- the water body is not available to each source;

2), WLAs, expressed as total recoverable instead, this capacity must be apportioned

metal, are calculated to meet the dissolved between all three sources via the TMDL

CCC and dissolved CMC at the edge of the procedure.

mixing zone assuming that the effluent is

mixed rapidly and that a simple, mass-balance The three permitted point sources in

equation is appropriate. our example all operate within the effluent

Chronic and acute WLAs (for any permits. They do not, however, address

single source, without consideration of other cumulative impacts of all three sources. 

sources) can be calculated at the 7Q10 and Permits for the two metal finishing facilities

1Q10 flows, respectively, for total recoverable specify a maximum daily limit (MDL) of

copper concentration, using Equation 3. 3380 μg/L and an average monthly limit

where [Cinstream] is calculated from Equation 2, effluent concentrations. At an average

Qe is the effluent flow, concentration of 81 μg/L of total recoverable

Qs is the receiving water flow, and copper and an increased effluent flow of 80

C is the background (upstream ) cfs, the load from the POTW (see Box A-3) s

concentration. would be 35 lbs/day. The increased flow

A.6 Calculating the TMDL for Multiple

Point Sources

The previous section shows the

calculation of wasteload allocations for a

single point source. Concentrations in the

receiving water, however, are influenced by

all three point sources simultaneously. In

limits specified in their current NPDES

(AML) of 2070 μg/L. 

In addition to potential impairment

under current permit limits, the POTW is

undergoing a significant (60%) capacity

expansion, and its increased effluent flow will

also increase copper loading at current

from the plant also has a significant impact on

low flow volumes in the receiving water,

requiring recalculation of the WLAs. 

The TMDL analysis is

straightforward when multiple, steady-state

sources are considered using hydrologically

based design conditions. The strategy is to:
TMDL WQC ( Qe Qs

)

TMDL [Cinstream] ( Qe Qs

)

34

Box A-3. Conversion Factors for

Concentration and Load

Concentration to load rate:

(μg/L) x (cfs) x 0.005394 = (lbs/day)

Load rate to concentration:

(lbs/day) / (cfs) x 185.4 = (μg/L)

(5)

(6)

(1) calculate the acute and chronic dissolved

(for metals) criteria concentrations [Eqn 1], 

(2) calculate the instream concentration

[C ] (in terms of total recoverable metal) instream

that equates to the dissolved criterion

concentration [Eqn 2], 

(3) calculate the total loading capacity

(TMDL) of the waterbody (in terms of total

recoverable metal) [Eqn 6], 

(4) calculate the background load, 

(5) calculate the allocatable portion of the

loading capacity (i.e., the difference between

the loading capacity and background) [Eqn 7], 

(6) calculate the current loadings from the

sources and their fractional contributions to

the total current load, 

(7) compare the current total loadings to the

waterbody with the required TMDL (if either

the acute or chronic total loadings exceed the

TMDL then the loads must be reduced), and 

(8) reduce loadings from the point sources,

equitably allocating waste loads to the

discharging facilities. 

The steady-state TMDL for a given

location or reach of the river is calculated (in

units of cfs - μg/L) as:

where 

 Q is the total flow of effluents e

discharging to the reach (cfs), 

Qs is the appropriate flow ( e.g.,

7Q10) of the river upstream of all the

discharges (cfs), and

WQC is the water quality criterion

expressed in μg/L. 

TMDLs for metals are developed on

the basis of the instream total recoverable

metal concentrations that equate to the

dissolved criteria concentrations. 

Consequently, the term WQC in Equation 5 is

replaced with the term [Cinstream] as calculated

by Equation 2.

The calculated TMDL is then divided

among WLAs for point sources; LAs, for

nonpoint sources and background loads; and a

margin of safety (MOS). The TMDL and the

portion of the TMDL taken up by background

load (at 4 μg/L) can be calculated in terms of

total copper mass, as shown in Table A-1.

Because the current loading for the

chronic TMDL exceeds the allocatable

portion, loadings from all of the NPDES

permitted sources must be reduced. Many

different mechanisms or schemes for

apportioning the necessary reductions in

allocations are possible. Assume for the

purpose of this example that the State has

determined that necessary reductions will be

applied equally to all point sources. Reduced

TMDL-based WLAs can then be calculated

based on the current proportion of load

attributable to a given source:
WLAi

TMDL Background x f

i

35

(7)

where WLA is the WLA for source I, and f

i i

is the proportion of the existing load

attributable to a given source.

The allocation fraction, f

i

, is simply a

proportionality constant that is arrived at by

dividing the current load from sourcei by the

sum of all the loads (e.g., f1 = PS1 / (PS1 +

PS2 + POTW + MOS)). The allocation

fraction is then multiplied by the Allocatable

Portion to yield the Allowed Load as in Table

A-2. In the calculations summarized in Table

A-2 and A-3, a MOS of 10 percent of the

allowable TMDL has been applied.
36

Table A-1. Calculation of TMDL (Total Recoverable Copper)

Acute TMDL Chronic

TMDL 

TMDL (total recoverable copper) (lbs/day) 44.11 33.76

[Eqn 6]

Background (total recoverable copper) at design flow (lbs/day) 2.41 3.02

[Background = Q * C ] s s

Allocatable Portion (lbs/day) 41.69 30.73

[Allocatable Portion = TMDL - Background]

Current Loading (lbs/day) 42.38 42.99

 [Loading = PS1 + PS2 + POTW +Background]

.

Table A-2. Allocation of Loads to Achieve the (Chronic) TMDL

Source Current Load Allocation Allocatable Allowed Load

(lbs/day) Fraction Portion (lbs/day)

(f )i 

(TMDL - Background)

PS1 1.67 0.04 30.73 1.16

PS2 3.35 0.08 30.73 2.32

POTW 34.95 0.79 30.73 24.18

MOS 4.44 0.10 30.73 3.07

SUM 44.41 1 30.73
37

Table A-3. Allocation of Loads to Achieve the (Acute) TMDL

Source Current Load Allocation Allocatable Allowed Load

(lbs/day) Fraction Portion (lbs/day)

(f )i 

(TMDL - Background)

PS1 1.67 0.04 41.69 1.57

PS2 3.35 0.08 41.69 3.14

POTW 34.95 0.79 41.69 32.81

MOS 4.44 0.10 41.69 4.17

SUM 44.41 1 41.69
LTAc WLA exp [0.5

2

4

z

99 4

]

24.18 lbs/day 0.87

21.0 lbs/day

LTAa32.81 lbs/day 0.76

24.9 lbs/day

38

Box A-4. Calculation of LTA

Multipliers

LTAc

CV = 0.12

z99 = 2.326

2 4 = ln [CV2/4+1] = 0.00359

exp [0.5 2 4 99 4 – z ] = 0.87

LTAa

CV = 0.12

z99 = 2.326

2 = ln [CV2+1] = 0.014297

exp [0.5 2 - z99 ] = 0.76

(9)

(10)

A.7 Calculating the Permit Limits for a

Point Source

Permit limits for the POTW are

developed in accordance with USEPA

(1991a) guidance on establishing WLAs and

permit limits for single sources. In

accordance with NPDES regulations, effluent

limits for the POTW are expressed in the

permit as mass units (pounds per day total

recoverable copper), using the conversion

factors shown in Box A-3. The WLA for c

total recoverable copper (Table A-2) is

equivalent to 24.18 lbs/day and is more

restrictive than the WLAa 32.81 lbs/day

(Table A-3). Converting the WLA to a

permit limit involves two additional

considerations: (1) there is variability in the

effluent concentration, and concentrations on

any given day may be greater or less than the

average value used to calculate the WLA; and

(2) permit compliance will be assessed from

limited sampling (e.g., weekly), which means

there will be uncertainty in the estimation of

actual load from the facility. These issues are

addressed by (1) calculating a long-term

average (LTA) which accounts for the

variability in actual load, and (2) using the

LTA to calculate a maximum daily limit

(MDL) and average monthly limit (AML)

which serve as trigger values for compliance

monitoring.

The permit limits are developed using

a steady-state, two-value WLA model, as

described in Chapter 5 of USEPA (1991a). 

First, variability in effluent load, expressed

through the coefficient of variation (CV), is

incorporated into the calculation of

appropriate long-term averages (LTAs). The

chronic long-term average (LTA ) for copper c

was calculated from

where the value for the factor exp [0.5 4

2 –

z ] was calculated from the coefficient of 99 4

variation of effluent concentrations (CV,

defined as standard deviation divided by the

mean, and assumed to be 0.12) by the

methods of USEPA (1991a, Table 5-1), using

the 99th percentile occurrence probability

(Box A-4).

The acute LTAa was calculated in a

similar manner, again using a 99th occurrence

probability as a multiplier:
MDL LTA exp [z

99 0.5

2

]

21.0 lbs/day 1.37

28.8 lbs/day

AML LTA exp [z

99 n

0.5

2

n

]

21.0 lbs/day 1.15

24.2 lbs/day

39

(11)

(12)

The limiting LTA for copper discharges from

the facility is the smaller of the LTA a and

LTAc, or 21.0 lbs/day. This is well below the

current average load from the facility of 43.95

lbs/day.

The permit for the POTW is written

to ensure an LTA load not to exceed 21.0

lbs/day total recoverable copper through the

specification of an MDL and AML for

compliance monitoring. The MDL for copper

is calculated using the expression

where the value for exp [ z – 0.5 2] is 99

taken from Table 5-2 in USEPA (1991a),

using a CV value of 0.12 and the column for

the 99th percentile basis. The AML for

copper is calculated from

where the value for exp [ z – 0.5 2] is 99 n n

taken from Table 5-2 in USEPA (1991a), in

which n equals 4 samples per month for total

recoverable copper, using the 99th percentile

basis.
40

APPENDIX B

Table B-1. Comparison of average fD data from three locations in the U.S. Three different

calculation methods are used with the Pima County data.

NY/NJ Boulder, Pima County, AZ

Harbor CO

Cd/Ct Cd/(Cd+Cp) by regression

from logKp

Copper 0.56 0.23 0.37 0.43 0.42

Cadmium 1.00 0.51 0.71 0.51 0.69

Lead 0.18 0.29 0.20 0.28 0.26

Nickel 0.86 ~ 1.0 --- --- ---

Zinc 0.90 0.44 0.61 0.63 0.65

These data illustrate two points. First,

notice the similarity in the values of the

translators for each of the metals in the Pima

County study. The differences between

column 1 and column 2 of the Pima County

data arise from limits in the analytical

precision of measurements of dissolved and

particulate sorbed fractions. Second, notice

the differences in the values of the translators

between the three sites represented in this

table. These differences reflect the site

specificity of the translator, further

strengthing the case for development of site

specific translator values in contrast to the use

of nation wide values.

Preliminary data collected for the

City of Palo Alto Regional Water Quality

Control Plant permit renewal process (Table

B-2) suggest a translator value of 0.62 for

copper (62% of the copper in the downstream

water is dissolved). This differs from all of

the translator values in Table B-1.
Station# Date Cd Ct Cp TSS fD

Station 1 9/7/89 2.6 3.4 0.8 89 0.76

Station 1 10/2/89 3.3 4.5 1.2 290 0.73

Station 1 10/25/89 3 4 1 52 0.75

Station 1 1/10/90 2.9 4.1 1.2 49 0.71

Station 1 2/7/90 1.4 8 6.6 228 0.18

Station 1 3/7/90 3 5 2 77 0.60

Station 1 7/9/90 4.2 9.6 5.4 180 0.44

Station 1 8/7/90 6.3 7 0.7 83 0.90

Station 1 9/19/90 3.6 5.7 2.1 125 0.63

Station 1 12/12/90 2.9 5.9 3 57 0.49

Station 1 1/10/91 3.5 4.3 0.8 46 0.81

Station 1 2/13/91 4 4.7 0.7 55 0.85

Station 1 10/10/91 4.3 4.6 0.3 78 0.93

Station 1 2/19/92 2 9.9 7.9 250 0.20

Station 2 9/7/89 3 5 2 110 0.60

Station 2 10/2/89 2.2 4.5 2.3 160 0.49

Station 2 10/25/89 6 11 5 132 0.55

Station 2 1/10/90 2.9 4.1 1.2 46 0.71

Station 2 2/7/90 1.7 6.1 4.4 110 0.28

Station 2 3/7/90 4.3 5 0.7 60 0.86

Station 2 7/9/90 6.8 7.2 0.4 100 0.94

Station 2 8/7/90 6.5 8.2 1.7 48 0.79

Station 2 9/19/90 3.9 5.6 1.7 65 0.70

Station 2 12/12/90 2.8 4.6 1.8 51 0.61

Station 2 1/10/91 4.2 4.8 0.6 61 0.88

Station 2 2/13/91 4.5 4.8 0.3 47 0.94

Station 2 10/10/91 4.5 4.7 0.2 77 0.96

Station 2 2/19/92 2 4.9 2.9 120 0.41

Mean 3.7 5.8 2.1 101.6 0.67

Stdev 1.4 2.0 2.0 65.5 0.22

95% 6.4 9.8 6.2 243.4 0.94

25% 2.9 4.6 0.7 54.3 0.53

Geomean 3.4 5.5 1.4 86.6 0.62

41

Table B-2. Data Collected in Palo Alto, CA for Cu Permit Limit from a Waste Water

Treatment Plant.
42

APPENDIX C C.2. The Translator is the Ratio of

C. Developing the Metals Translator

s may be concluded from the calculated from data collected over some Adiscussion in Chapter 2, period of time and some range of flow

there are several ways of conditions. For example, samples may be

developing the metals translator. This collected weekly for three months under

Appendix presents two suggested possibilities conditions of “relatively low flow” (which

and illustrates their application. may or may not include design low flow

C.1. Minimum Data Requirements

Samples should be collected to expect to have a broad range of TSS

characterize completely mixed effluent plus conditions. The dissolved fraction may be

receiving water downstream of the discharge determined (directly) from measurements of

(such as should occur at, or below, the edge dissolved and total recoverable metal

of the mixing zone). These represent the concentrations collected from waters

absolute minimum in data requirements. downstream of the effluent discharge. The

Ideally, samples should be collected from the dissolved fraction may be related to a constant

effluent and the upstream receiving water adsorbent concentration associated with low

(before mixing with the effluent ) to quantify flow conditions or a function of varying

metal loading and background adsorbent concentrations.

concentrations. An alternative to collecting

the downstream samples on site is to combine Note that this ratio (C /C ), as

upstream and effluent waters to meet the exemplified by Eqn 2.6 and 2.7, is not a

desired dilution fraction in the mixing zone. partition coefficient but it does embody a

In addition, there may be occasions when it is partition coefficient. As shown by Eqn 2.3

desirable to collect samples to characterize and Eqn 2.8, the partition coefficient is the

the far-field conditions, particularly when ratio of the particulate-sorbed and the

encountering deposits containing metals, mine dissolved metal species. The dissolved

tailings, drainage waters of high acidity, or fraction and the partition coefficient are

different geologic substrates. related according to f = (1 + K • m) . It is

To keep this simple and to avoid fraction (f ) and the partition coefficient (K )

having to develop data on the kinetics of because what we're interested is the dissolved

metal adsorption and desorption, the translator fraction. We're only using the partition

should be developed to describe equilibrium coefficient because it is one way of getting to

partitioning. Equilibrium partitioning also the dissolved fraction. 

reduces the frequency for which far field

effects need to be investigated. It also lets us This guidance uses TSS as a default

apply the same translator for evaluation of parameter to represent all of the ion

both acute and chronic mixing zones. adsorption sites. It is generally recognized,

CD/CT

The translator is the fraction of the

total recoverable metal in the downstream

water that is dissolved ( fD D = C /C ). It is T

conditions) or samples may be collected

monthly for a period of one or more years

under a broad range of flow conditions. 

Under this latter sampling scheme we may

D T

D P

-1

important to distinguish between the dissolved

D P

however, that humic substances play a major
43

Box C-1. The Translator is the Dissolved

Fraction: fD D = C /CT

Step 1 - For each field sample determine 

 fD D = C /CT

Step 2 - If the translator is not dependent

on TSS, determine the geometric

mean

GM_fD= exp( ln(f )/ n) 1 D

n

and upper percentile values of the

dissolved fraction. If the data are

found not to be log-normal, then

alternative transformations should

be considered to normalize the

data and determine the

transformed mean and percentiles. 

Also, alternative upper percentiles

may be adopted as a state’s policy

to address MOS (e.ge., 90 or 95 th th

percentiles may be appropriate.)

Step 3 - If the translator is found to be

dependent on TSS, regression

equations relating f D to TSS should

be developed. Appropriate

transformations should be used to

meet the normality assumptions

for regression analysis (for

example log-transformation of f D

and TSS may be appropriate). The

regression equation or an upper

prediction interval may be

considered for estimation of f D

from TSS depending on the

strategy for addressing MOS.

role in the environmental fate and availability from Table 1 and following the sequence as

of metal ions in the environment. The humic outlined in Box C-1. The metal

and fulvic acids are mixtures of naturally concentrations in Table 1 are for lead. The

occurring polyelectrolytes that have different data records, numbers 1 through 27, represent

types of functional groups to which ions can spatially separate sampling stations in the

bind. Benedetti, et. al. (1995) write that metal estuary. The first step (Step 1 in Box C-1) is

binding in natural systems will be affected by to calculate the dissolved fraction in the

humic acids whose chemical heterogeneity receiving water. The result of this calculation

and polyelectric properties will affect metal is shown in Column 8 of Table 1. 

binding. Multivalent cations will compete for

the same sites, along with other ions and

protons in the aquatic systems, and hence

influence the binding of each other. 

The following step-by-step examples

are designed to guide the reader through

possible sequences of data analyses leading to

the development of the metals translator. One

set of data was collected during the New

York/New Jersey Harbor study. The data

presented here are a subset of the total and do

not include samples that are incomplete (i.e.,

records lacking pH or POC values) to

simplify this presentation. The data set

reflects spatial differences. The data are not a

time series at a single location. However,

there would not be a great difference in the

following analyses if the data did represent a

time series. 

The second data set was provided by

the Coors Brewing Company. Again, the data

presented here are a subset of the total. The

original data set contains time series data for

several variables at several locations. To

simplify this example, however, the data for

only one metal and one site are presented.

C.2.1. Spatial Example Using the Ratio of

CD/CT

The most direct procedure for

determining a site-specific metal translator is

simply to determine f D by measuring CT and

CD and to develop the dissolved fraction as

the ratio CD/CT. This is illustrated, using data
Lead

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 20 40 60

TSS

fD

Lead

-0.10

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

-1.00 0.00 1.00 2.00 3.00 4.00

ln (TSS)

fD 

R-Square = 0.77

44

Step 2 indicates that there is a lot of transformations would be appropriate. 

variation in the values of f D; the mean is 0.21 Examination of Figure 2 further supports the

with a standard deviation is 0.17. The logarithmic transformation of values and the

variability in this dataset indicates that it is choice of the geometric mean. Even at that,

unwise to attempt to spatially average f D the geometric mean value of the dissolved

values in this situation. To do so would be to fraction (0.16 does not provide a good

ignore spatially critical conditions. Because, representation of the waterbody in which TSS

it does not provide a good representation of is spatially correlated. The translator needs to

the waterbody, one cannot accept the mean f D account for the spatial and/or temporal

(0.21) as the translator. variability evidenced in the waterbody.

The translator should be calculated as

a geometric mean or other estimate of central

tendency (see Section 4.3). Use of the

arithmetic mean is appropriate when the

values can range from minus infinity to plus

infinity. The geometric mean is equivalent to

using the arithmetic mean of the logarithms of

the values. The dissolved fraction cannot be

negative, but the logarithms of the dissolved

fraction can be. The distribution of the 

Figure 1. Dissolved fraction (lead) vs TSS.

logarithms of the translator is therefore more

likely to be normally distributed. Figure 1

displays the arithmetic distributions of the

dissolved fractions with TSS. Note that the

skewed distributions suggest that logarithmic

In order to account for the spatial

variability of this waterbody, we need a

translator that can be tied functionally to

important physical or chemical variables. 

TSS concentrations vary spatially throughout

the estuary. Spatial variability in TSS

concentrations requires the use of a translator

that includes the relationship between TSS

and fD. This empirically derived relationship

is valid for this estuary.

Figure 2. Dissolved fraction (lead) vs log

transformation of TSS.

The regression of the natural

logarithm of fD against the natural logarithm

of TSS (Figure 2) provides a reasonably good

fit as evidenced by the R Square of 0.77. The
45

dissolved fraction is highly correlated with

TSS; therefore the translator (Figure 2) takes

the form of: 

ln(fD) = - 0.6017 - 0.6296 • ln(TSS).

The translator is the dissolved

fraction, not the regression equation. The

way to use the regression equation is to select

TSS concentrations that are representative of

specific locations in the estuary and calculate

fD values that serve as the translators for the

discharges in these respective locations. 

Sung, et.al. (1995) have demonstrated

a relationship between K and salinity for Cd, P

Cu, and Zn in the Savannah River Estuary. It

may well be that by considering salinity as

well as TSS, more variability could have been

accounted for in the relationship portrayed in

Figure 2.
No. pH POC TSS CT CD CP fD KP (CT/CD)-1

1 8.8 0.132 0.61 0.046 0.027 0.019 0.59 1.15 0.704

2 8.6 0.104 0.92 0.044 0.03 0.014 0.68 0.51 0.467

3 8.6 0.159 1.88 0.25 0.094 0.156 0.38 0.88 1.660

4 8.4 0.280 1.28 0.31 0.16 0.15 0.52 0.73 0.938

5 8.4 0.376 3.32 0.68 0.10 0.58 0.15 1.75 5.800

6 8.4 0.190 2.94 0.46 0.098 0.362 0.21 1.26 3.694

7 8.2 0.183 5.36 0.89 0.14 0.75 0.16 1.00 5.357

8 8.3 0.351 4.71 0.80 0.27 0.53 0.34 0.42 1.963

9 8.4 0.266 3.50 0.67 0.22 0.45 0.33 0.58 2.045

10 8.1 0.416 7.98 2.40 0.59 1.81 0.25 0.38 3.068

11 8.1 1.060 44.42 9.10 0.27 8.83 0.03 0.74 32.704

12 8.1 0.538 11.08 3.40 0.44 2.96 0.13 0.61 6.727

13 8.1 0.596 10.60 3.90 0.85 3.05 0.22 0.34 3.588

14 8.2 0.785 14.77 3.20 0.54 2.66 0.17 0.33 4.926

15 8.4 0.626 8.95 1.40 0.26 1.14 0.19 0.49 4.385

16 8.4 0.602 19.94 2.20 0.17 2.03 0.08 0.60 11.941

17 8.3 0.540 21.10 2.10 0.14 1.96 0.07 0.66 14.000

18 8.3 0.676 19.45 2.10 0.15 1.95 0.07 0.67 13.000

19 8.2 0.629 25.70 2.90 0.15 2.75 0.05 0.71 18.333

20 8.4 0.726 27.75 1.90 0.16 1.74 0.08 0.39 10.875

21 8.4 0.494 22.30 1.50 0.17 1.33 0.11 0.35 7.824

22 8.4 2.360 7.89 1.40 0.26 1.14 0.19 0.56 4.385

23 8.4 0.427 7.32 1.70 0.22 1.48 0.13 0.92 6.727

24 8.4 0.414 8.48 1.60 0.27 1.33 0.17 0.58 4.926

25 8.5 1.470 8.22 1.20 0.10 1.10 0.08 1.34 11.000

26 8.5 0.407 7.09 0.82 0.088 0.732 0.11 1.17 8.318

27 8.6 0.381 7.52 0.58 0.065 0.515 0.11 1.05 7.923

Mean 0.56 11.30 1.76 0.22 1.54 0.21 0.75 7.31

Stdev 0.46 10.23 1.80 0.19 1.72 0.17 0.36 6.77

95% 1.35 27.14 3.75 0.58 3.02 0.57 1.31 17.03

25% 0.32 4.11 0.68 0.10 0.52 0.10 0.50 3.33

Geomean 0.44 7.26 1.06 0.17 0.82 0.16 0.67 4.90

46

Table C-1. Example Data Used to Calculate Translator for Lead

(Source: NY/NJ Harbor Study)
DATE pH TSS CT CD (CT/CD)-1 fD

10/16/91 7.5 3 0.47 0.24 0.96 0.51

11/13/91 7.3 32 0.72 0.27 1.67 0.38

12/11/91 8.1 5 0.47 0.20 1.35 0.43

01/16/92 8.2 8 0.43 0.38 0.13 0.88

02/18/92 8.2 7 0.55 0.19 1.86 0.35

03/18/92 8.1 7 0.49 0.24 1.07 0.48

04/14/92 7.2 14 0.84 0.44 0.92 0.52

05/12/92 7.7 15 0.34 0.18 0.87 0.54

06/17/92 7.5 8 0.25 0.15 0.64 0.61

07/15/92 7.5 5 0.18 0.13 0.43 0.70

08/18/92 7.2 23 0.26 0.08 2.12 0.32

09/09/92 7.2 4 0.22 0.03 5.72 0.15

10/14/92 8.0 7 0.25 0.11 1.27 0.44

11/16/92 8.2 13 0.44 0.22 1.00 0.50

12/15/92 7.9 1 0.47 0.24 0.97 0.51

01/12/93 8.8 6 0.67 0.32 1.08 0.48

02/18/93 7.9 12 0.71 0.38 0.87 0.54

03/16/93 8.1 10 0.57 0.22 1.58 0.39

04/13/93 8.0 18 0.48 0.16 2.04 0.33

05/12/93 7.5 20 0.42 0.08 4.10 0.20

06/15/93 8.1 64.6 0.54 0.10 4.67 0.18

07/15/93 7.5 10 0.14 0.06 1.25 0.44

08/12/93 7.8 6 0.17 0.09 0.94 0.52

09/16/93 8.1 4 0.24 0.12 1.09 0.48

10/13/93 8.1 5 0.26 0.12 1.11 0.47

11/10/93 8.4 1.7 0.30 0.15 1.03 0.49

12/13/93 7.9 4.6 0.45 0.23 1.00 0.50

01/13/94 7.5 1.8 0.33 0.17 0.97 0.51

02/11/94 7.9 5.5 0.49 0.24 1.01 0.50

03/09/94 8.4 5 0.34 0.09 2.57 0.28

04/07/94 8.3 16 0.48 0.14 2.54 0.28

05/12/94 7.6 47.7 0.72 0.09 7.35 0.12

07/13/94 7.8 6 0.13 0.05 1.43 0.41

08/23/94 8.0 13 0.14 0.05 2.20 0.31

09/20/94 8.1 6 0.15 0.06 1.30 0.44

10/18/94 8.0 5.5 0.28 0.14 1.06 0.49

Mean 11.68 0.40 0.17 1.73 0.43

Stdev 12.90 0.19 0.10 1.50 0.15

95% 0.71 0.71 0.33 0.71 0.71

25% 5.00 0.25 0.09 0.97 0.34

Geomean 7.90 0.35 0.14 1.33 0.40

47

Table C-2. Time Series Example Calculating the Translator for Zinc.

(Source: Coors Brewing Company Study)
48

Box C-2. The Translator is the

Dissolved Fraction (fD)

Calculated via Site Specific

Partition Coefficients

Step 1 - For each field sample

determine 

C = C - C , P T D

K = C /(C • TSS) P P D

Step 2 - Fit least squares regressions to

data (transformed, stratified by

pH, etc.) as appropriate to

solve for K .P

Step 3 - Substitute the regression

derived value of K in Eqn 2.7, P

fD = (1 + K • TSS) P

-1

Step 4 Determine fD for a TSS value

representative of the critical

conditions.

C.2.2. Time Series Example Using the

Ratio of CD/CT

Using a data set developed over a partition coefficient, and the dissolved metal

three year time span on Clear Creek in

Colorado and the same analytical procedure

as described in Box 1, f D is calculated as the

ratio of CD/CT. A subset of the collected

data, Table C-2, illustrate the approach. 

This subset includes the following

variables: total recoverable Zn, dissolved Zn,

TSS, and pH that were measured at one

sampling location. Additionally, presented in

Table 2 are fD values (Box C-1 - Step 1). 

This data set was censored in the following

manner. When calculating fD, if the dissolved

concentration was found to exceed the total

recoverable concentration, CD was set equal

to CT and fD calculated as 1 (100% dissolved

metal). 

At the pH levels encountered in Clear

Creek during the three year sampling period, 

no relationship was obtained between pH and

fD. This is not an unexpected result because

pH is in the 7 to 9 range; the major effect of

pH on the dissolved fraction is normally

observed at low pH levels. Relationships

based on POC (not shown) provide no

improvement over the TSS based

relationships.

The translator value selected for Zn between total recoverable and dissolved

on Clear Creek is the geometric mean of the metal concentrations. The partition

fD values (0.40). coefficient the ratio of the particulate-sorbed

C.3. The Translator Calculated Using

Site Specific Partition Coefficients

It is important to remember with this

method, as with the previous method, that the

translator is the dissolved fraction in the

downstream water. 

Box C-2 provides a procedure for developing

the translator via partition coefficients. In

Step 1 calculate the particulate fraction, the

fraction. CP is calculated as the difference 17

and the dissolved metal species times the

adsorbent concentration (Eqn 2.9). The

The particulate fraction can also be 17

measured in the laboratory by filtering the solids,

scraping the solids from the filter, drying,

weighing, and subjecting to appropriate chemical

analyses. The increased number of steps may

provide opportunities for additional sources of

error, accompanied by increased uncertainty. See

Eqn 2.2, 2.3, and 2.4.
Lead

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1.600

1.800

0 10 20 30 40 50

TSS

Kp

R-Square = 0.11

Lead

0.000

5.000

10.000

15.000

20.000

25.000

30.000

35.000

0 10 20 30 40 50

TSS

(Ct/Cd)-1

(Ct/Cd)-1 = 0.62402 * TSS

R-Square = 0.81

49

dissolved fraction and the partition

coefficient are related according to Eqn 2.7.

C.3.1. Spatial Example Using Partition

Coefficients

Using the same NY/NJ Harbor data

as used above (Table C-1), this example 

Figure 3. K as a function of TSS. P

demonstrates the calculation of K and how it P

may be used to arrive at site-specific values

of fD . 

The partition coefficient - TSS data

are not as well behaved (Figure 3) as are the

fD -TSS data. However, Shi, et. al. (1996)

show that after algebraic rearrangement of

Eqn 2.7 to 

(Ct/Cd)-1 = K • TSS, P

 KP can be obtained by linear regression. The

slope of the curve is the partition coefficient

(Figure 4). 

Figure 4. The fraction [(Ct/Cd)-1] as a

function of TSS.

By regression analysis, KP = 0.624

L/mg. This value is used in Eqn 2.7 along

with an appropriate value of TSS to calculate

the translator.

C.3.2. Time Series Example Using

Partition Coefficients

Continuing the analysis of data

collected from Clear Creek, this section

demonstrates estimating the dissolved

fraction by using a site-specific partition

coefficient. The particulate sorbed fraction is

operationally defined as CT - CD and the

partition coefficient is calculated as a

function of TSS according to Equation 2.8

following the procedure given in Box 2 - Step

1. Table C-2 presents the data generated by

the field study as well as the calculated

values. 

Substitute the regression derived

value of KP in Eqn 2.7, as suggested in Box 2

- Step 3. As in the previous example, the

way to use this equation is to select TSS

concentrations that are representative of
Zinc

0

1

2

3

4

5

6

7

8

0 20 40 60 80

TSS

(Ct/Cd)-1

(Ct/Cd)-1 =0.107885 * TSS

R-Square = 0.23

50

critical conditions in the receiving waterbody

and calculate the dissolved fractions

(translator values) .

Figure 5. The fraction [(Ct/Cd)-1] as

a function of TSS.
51

APPENDIX D

D.1. Sample Size

tatistically, the most A sample size of 4, therefore, would Simportant objective for a determine that a difference exists only if the

metal translator study is to difference between the means is 4 or more. 

determine the mean concentrations of total At very low concentrations typical of many

and dissolved metal within an acceptable metals—for example, if the dissolved copper

confidence interval of the true mean such that concentration is 3 g/L and the total

the estimated dissolved fraction is a good concentration is 6 g/L and is 1 g/L—this

representation of the true dissolved fraction. sample size would not be adequate to

The null hypothesis (H0) is:mean translator would be rejected, therefore, even

total concentration ( ) = mean dissolved though it is actually valid. A sample size of t

concentration ( d

). 8, on the other hand, would be large enough

To determine sample size, three and support the use of a translator other than

factors must be selected: 1.

1. Type I error ( ) is the probability of A sample size of 10 (or greater) is

rejecting a true hypothesis. recommended because it would allow

2. Type II error ( ) is the probability of demonstration of a significant difference for

accepting a false hypothesis. somewhat less than 2.0, while still keeping

3. The expected difference between the = = 0.05. Furthermore, if 1 or 2 samples

means ( ), expressed as a multiple of have to be discarded because of undetectable

the standard deviation ( ), which is concentrations, outlier concentrations, or

assumed to be equal for the two other sampling or analytical problems, there

populations ( = = ): would still be an adequate number of samples t d

 = ( t - d) ÷ only really reliable method of estimating how

For a translator study, the null collect some data, examine the statistical

hypothesis is assumed to be false, i.e., there variability, and project from that basis.

is a difference between total and dissolved

concentrations. Therefore, must be small

to ensure that a translator is not rejected (no

difference detected between the means) when

a difference does exist. For and levels of

0.05, the following shows the relationship

between and n, assuming a t distribution:

n

0.05 0.05 1.0 27

2.0 8

3.0 5

4.0 4

demonstrate that a difference exists. The

to show a difference between the two means

to meet the assumed statistical criteria. The

many samples are going to be needed is to
52

APPENDIX E

E.1. Topics covered in Method 1669

include:

ontamination control, Quality assurance/quality control Cincluding: minimizing procedures, including: collection of

exposure of the sample, the an equipment blank, field blank, and

wearing of gloves, use of metal-free field duplicate.

apparatus, and avoiding sources of

contamination. Re-cleaning procedures for cleaning

Safety, including: use of material sites.

safety data sheets and descriptions of

the risks of sampling in and around Suggestions for pollution prevention

water and in hot and cold weather. and waste management.

Apparatus and materials for Twenty references to the technical

sampling, including: descriptions and literature on which the Method is

part numbers for sample bottles, based and a glossary of unique terms

surface sampling devices such as used in the Method.

poles and bottles, a subsurface jar

sampling device, continuous flow

samplers including peristaltic and Table E-1 details some of the

submersible pumps, glove bag for differences between standard sampling for

processing samples, gloves, storage metals and sampling for trace metals using

bags, a boat for collection of samples the procedures outlined below and detailed in

on open waters, filtration apparatus Method 1669. 

consistent with the apparatus studied

and used by USGS, and apparatus for

field preservation of samples.

Reagents and standards for sample

preservation, blanks, and for

processing samples for determination

of trivalent chromium.

Site selection

Sample collection procedures,

including: "clean hands/dirty hands"

techniques, precautions concerning

wind direction and currents, manual

collection of surface and sub-surface

samples, depth sampling using a jar

sampler, and continuous flow

sampling using a pump.

Field filtration and preservation

procedures using an inflatable glove

bag, and instructions for packaging

and shipment to the laboratory.

the equipment and apparatus between
53

Table E-1. Standard vs. Trace Metals Sampling

Component Standard Sampling Technique Trace Metals Sampling

(USEPA, 1983, 1991b) Technique (USEPA, 1995a)

Bottles Borosilicate glass, Fluoropolymer, polyethylene,

polyethylene, polypropylene, or or polycarbonate, filled and

Teflon stored with 0.1% ultrapure HCl ®

solution

Cleaning Wash with detergent; rinse Detergent wash, DI water

successively with tap water, 1:1 rinse, soak for 2 h minimum in

HNO , tap water, 1:1 HCl, tap hot, concentrated HNO , DI 3

water, deionized distilled water water rinse, soak for 48 h

(GFAA methods; EPA, 1983). minimum in hot, dilute

Soak overnight; wash with ultrapure HCl solution, drain,

detergent; rinse with water; fill with 0.1% ultrapure HCl

soak in HNO3:HCl:water solution, double bag, and store

(1:2:9); rinse with water; oven until use.

dry (ICP Method 200.7;

USEPA, 1991b)

3

Gloves No specification. Powder-free (non-talc, class100) latex, polyethylene, or

polyvinyl chloride.

Filter 0.45 μm membrane; glass or Gelman #12175 capsule filter

plastic filter holder or equivalent capacity 0.45 μm

filter with a minimum 600 cm 2

filtration area. Rinsing the

#12175 filter with 1000 ml

ultrapure water is adequate

cleaning for current ambient

level determinations.

Preservative Conc. redistilled HNO , 5 ml/L Ultrapure HNO to pH <2 or 3

(GFAA methods; USEPA, lab preserve and soak for 2

1983). 1:1 HNO to pH <2 days. Lab preserve samples 3

(3ml/L) (ICP Method 200.7; for mercury to preclude

USEPA, 1991b) atmospheric contamination.

3
54

E.2. Method of Sampling

Sampling Method 1669 (USEPA, submerges the sampling device to the desired

1995a) provides detailed guidance on steps depth and pulls the cord to fill the sample

that can be followed to collect a reliable bottle. After filling, rinsing, and retrieval,

sample and preclude contamination. Choose "clean hands" removes the sample bottle

manual or continuous sampling depending from the sampling device, caps the bottle,

upon which method is best for the specific and places it in the sample bag. "Dirty

sampling program. Only trained personnel hands" reseals the bag for further processing

should be entrusted the task of sample or shipment.

collection. 

E.2.1. Manual Sampling of Surface E.2.3. Grab Sampling of Subsurface

Water or Effluent Water or Effluent Using a Jar

In the manual sampling procedure,

the sampling team puts on gloves and orients In sampling with the jar sampling

themselves with respect to the wind and device, "dirty hands" removes the device

current to minimize contamination. "Dirty from its storage container and opens the outer

hands" opens the sample bag. "Clean hands" bag. "Clean hands" opens the inner bag,

removes the sample bottle from the bag, removes the jar sampler, and attaches the

removes the cap from the bottle, and discards pump to the flush line. "Dirty hands" lowers

the dilute acid solution in the bottle into a the weighted sampler to the desired depth and

carboy for wastes. "Clean hands" submerges turns on the pump, allowing a large volume

the bottle, collects a partial sample, replaces of water to pass through the system. After

the cap, rinses the bottle and cap with stopping the pump, "dirty hands" pulls up the

sample, and discards the sample away from sampler and places it in the field-portable

the site. After two more rinses, "clean glove bag. "Clean hands" aliquots the sample

hands" fills the bottle, replaces the cap, and into various sample bottles contained within

returns the sample to the sample bag. "Dirty the glove bag. If field filtration and/or

hands" reseals the bag for further processing preservation are required, these operations

(filtration and/or preservation) or for are performed at this point. After

shipment to the laboratory. filtration/preservation, "clean hands" caps

E.2.2. Grab Sampling of Subsurface

Water or Effluent Using a Pole

Sampler 

In sampling with the pole (grab)

sampling device, "dirty hands" removes the

pole and sampling device from storage and

opens the bag. "Clean hands" removes the

sampling device from the bag. "Dirty hands" In the continuous-flow sampling

opens the sample bag. "Clean hands" technique using a submersible pump, the

removes the sample bottle, empties the dilute sampling team prepares for sampling by

acid shipping solution into the carboy for setup of the pump, tubing, batteries, and, if

wastes, and installs the bottle in the sampling

device. Using the pole, "dirty hands"

Sampler

each bottle and returns it to its bag. "Dirty

hands" seals the bag for shipment to the

laboratory.

E.2.4. Continuous Sampling of Surface

Water, Subsurface Water, or

Effluent Using a Submersible

Pump
55

required, the filtration apparatus. "Clean To preclude contamination from

hands" removes the submersible pump from atmospheric sources, mercury samples should

its storage bag and installs the lengths of be shipped unfiltered and unpreserved via

tubing required to achieve the desired depth. overnight courier and filtered and/or

"Dirty hands" connects the battery leads and preserved upon receipt at the laboratory.

cable to the pump, lowers it to the desired

depth, and turns on the pump. The pump is

allowed to run for 5 - 10 minutes to pump 50

- 100 liters through the system. If required,

"clean hands" attaches the filter to the outlet Because the operational definition of

tube. "Dirty hands" unseals the bag “dissolved” is so greatly affected by filtration

containing the sample bottle. "Clean hands" artifacts, the Gelman #12175 capsule filter or

removes the bottle, discards the dilute acid equivalent capacity filter must be used,

shipping solution into the waste carboy, regardless of how the samples are collected. 

rinses the bottle and cap three times with (The next largest capacity filter is

sample, collects the sample, caps the bottle, approximately 80 cm surface area.) The

and places the bottle back in the bag. "Dirty minimization of filtration artifacts can be

hands" seals the bag for further processing or assured with high capacity tortuous path

shipment. filters and limited sample volume ( 1000

E.3. Preservation

Samples to be analyzed for total Method 1669 is used for samples collected

recoverable metals are preserved with using the manual, grab, or jar collection

concentrated nitric acid (HNO 3) to a pH less systems. In-line filtration using the

than 2. In normal natural waters, 3-5 ml of continuous-flow approach was described

acid per liter of sample is recommended above. The filtration procedure used in

(EPA, 1983, 1991b) to achieve the required Method 1669 is based on procedures used by

pH. The nitric acid must be known to be free USGS, and the capsule filter is the filter

of the metal(s) of interest. Method 1669 evaluated and used by USGS.

provides specifications for the acid. Samples

for total recoverable metals should be The filtration system is set up inside

preserved immediately after sample a glove bag, and a peristaltic pump is placed

collection. It is common for laboratories to immediately outside of the glove bag. 

recommend sample acidification in a Tubing from the pump is passed through

controlled uncontaminating environment for small holes in the glove bag to assure that all

both total recoverable and dissolved metal metallic parts of the pump are isolated from

fractions. the sample. The capsule filter is also placed

Field preservation is necessary for

trivalent and hexavalent chromium. Field Using "clean hands/dirty hands"

preservation is advised for hexavalent techniques, blank water and sample are

chromium in order to provide sample pumped through the system and collected. 

stability for up to 30 days. The sample is acidified, placed back inside

E.4. Filtration

2

ml). The Gelman #12175 capsule filter has

equivalent filtration area of 600 cm .

2

The filtration procedure given in

inside the glove bag.

the sample bag, and shipped to the

laboratory.
56

E.5. Field Quality Assurance

The study plan should describe the

sampling location(s), sampling schedule, and Field blank - In order to demonstrate

collection methodology, including explicit that sample contamination has not

information on the sampling protocol. occurred during field sampling and

Detailed requirements and procedures for sample processing, at least one (1)

field quality control and quality assurance are field blank must be generated for

given in USEPA Method 1669. If Method every ten (10) samples that are

1669 is not used, deviations from that collected at a given site. The field

Method should be described and the Method blank is collected prior to sample

should be supplemented by standard collection and should be collected for

operating procedures (SOPs) where each trip to a given site if fewer than

appropriate. It is desirable to include blind 10 samples are collected per

QC samples as part of the project. sampling trip.

Equipment blank - Prior to the use of Field blanks are generated by filling a

any sampling equipment at a given large, pre-cleaned carboy or other

site, the laboratory or equipment appropriate container with reagent

cleaning contractor is required to water (water shown to be free from

generate equipment blanks to metals at the level required) in the

demonstrate that the equipment is laboratory, transporting the filled

free from contamination. Two types container to the sampling site,

of equipment blanks are required: processing the water through each of

bottle blanks and sampling equipment the sample processing steps and

blanks. equipment (e.g., tubing, sampling

Equipment blanks must be run on all in the field, collecting the field blank

equipment that will be used in the in one of the sample bottles, and

field. If, for example, samples are to shipping the bottle to the laboratory

be collected using both a grab for analysis.

sampling device and the jar sampling

device, then an equipment blank must If it is necessary to clean the

be run on both pieces of equipment. sampling equipment between

The equipment blank must be collected after the cleaning

analyzed using the same analytical procedures but before the next

procedures used for analysis of sample is collected.

samples so that contamination at the

same level is detected. If any Field duplicate - A field duplicate is

metal(s) of interest or any potentially used to assess the precision of the

interfering substance is detected in field sampling and analytical

the equipment blank, the source of processes. It is recommended that at

contamination/interference must be least one (1) field duplicate sample

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.

devices, filters, etc.) that will be used

samples, a field blank should be
57

be collected for every ten (10) samples that

are collected at a given site or for each

sampling trip if fewer than 10 samples are

collected per sampling trip.

The field duplicate is collected either

by splitting a larger volume into two

aliquots in the glove bag, by using a

sampler with dual inlets that allows

simultaneous collection of two

samples, or by collecting two

samples in rapid succession.
58

APPENDIX F

F.1. Laboratory Facility, Equipment,

and Reagents

any of the laboratories analyzing an aliquot from the lot using the Mpresently performing techniques and instrumentation to be used for

metals determinations are analysis of samples. The lot will be

incapable of making measurements at or near acceptable if the concentration of the metal

ambient criteria levels because of limitations of interest is below the detection limit of the

in facilities, equipment, or reagents. The QC method being used. Ultrapure acids are

Supplement suggests the facilities available and should be used to preclude

modifications necessary to assure reliable contamination from this source, although

determinations at these levels. The technical grades of acid may be pure enough

modifications required can be extensive or to be used for the first steps in the cleaning

minimal, depending on the existing processes.

capabilities of the laboratory. The ideal

facility is a class-100 clean room with walls Reagent water--water demonstrated

constructed of plastic sheeting attached to be free from the metal(s) of interest and

without metals fasteners, down-flow potentially interfering substances at the

ventilation, air-lock entrances, pass-through method detection limit (MDL) for that metal

doors, and adhesive mats for use at entry in the analytical method being used--is

points to control dust and dirt from entering critical to reliable determination of metals at

via foot traffic. If painted, paints that do not trace levels. Reagent water may be prepared

contain the metal(s) of interest must be used. by distillation, deionization, reverse osmosis,

Class-100 clean benches, one other techniques that remove the metal(s) and

installed in the clean room; the other adjacent potential interferant(s).

to the analytical instrument(s) for preparation

of samples and standards, are recommended

to preclude airborne dirt from contaminating

the labware and samples.

All labware must be metal free. Part 136 may not be sufficiently sensitive for

Suitable construction materials are trace metals determinations. The Agency

fluoropolymer (FEP, PTFE), conventional or believes dischargers may use more sensitive

linear polyethylene, polycarbonate, or methods, such as stabilized temperature

polypropylene. Only fluoropolymer should graphite furnace atomic absorption

be used when mercury is a target analyte. spectroscopy (STGFAA) and inductively

The QC supplement suggests cleaning coupled plasma/ mass spectrometry

procedures for labware. Gloves, plastic (ICP/MS) (USEPA, 1994c) even though

wrap, storage bags, and filters may all be those methods have not yet been approved in

used new without additional cleaning unless 40 CFR Part 136 for general use in Clean

results of the equipment blank pinpoint any Water Act applications. In some instances,

of these materials as a source of STGFAA and ICP/MS may be preceded by

contamination. In this case, either an hydride generation or on-line or off-line

alternate supplier should be found or the

materials will need to be cleaned.

Each reagent lot should be tested for

the metals of interest by diluting and

anodic/cathodic stripping voltammetry, or

F.2. Analytical Methods

The test methods currently in 40 CFR

preconcentration to achieve these levels. The
59

Agency is developing methods for those analysis of samples. This

metals that cannot as yet be measured at demonstration is comprised of tests

ambient criteria levels. The methods being to prove that the laboratory can

developed use the apparatus and techniques achieve the MDL in the EPA method

described in the open technical literature. and the precision and accuracy

This guidance does not address the use on specified in the QC Supplement.

non-Part 136 methods in any context other

than metal translator studies performed by Analyses of blanks are required

the discharger. initially and with each batch of

Although analyses by STGFAA are process at the same time to

generally cheaper than those by ICP/MS, the demonstrate freedom from

cost differences are usually not a limiting contamination.

consideration given the implications of

obtaining a precise and accurate translator The laboratory must spike at least

value. Achieving low detection levels can 10% of the samples with the metal(s)

add appreciably to the cost, but those costs of interest to monitor method

may be justified if a translator means the performance. When results of these

difference between permit compliance and spikes indicate atypical method

noncompliance. performance for samples, an

F.3. Laboratory Quality Control

The QC Supplement provides

detailed quality control procedures that The laboratory must, on an ongoing

should assure reliable results. The QC basis, demonstrate through

Supplement requires each laboratory that calibration verification and through

performs trace metals determinations to analysis of a laboratory control

operate a formal quality assurance program. sample that the analytical system is

The minimum requirements of this program in control.

consist of an initial demonstration of

laboratory capability, analysis of samples The laboratory must maintain records

spiked with metals of interest to evaluate and to define the quality of data that are

document data quality, and analysis of generated.

standards and blanks as tests of continued

performance. Laboratory performance is In recognition of advances that are

compared to established performance criteria occurring in analytical technology, the

to determine if the results of analyses meet analyst is permitted to exercise certain

the performance characteristics of the options to eliminate interferences or lower

method. This formal QA program has the the costs of measurements. These options

following required elements: include alternate digestion, concentration,

The analyst must make an initial instrumentation. Alternate determinative

demonstration of the ability to techniques, such as the substitution of a

generate acceptable accuracy and colorimetric technique or changes that

precision with the method used for degrade method performance, are not

samples started through the analytical

alternative extraction or cleanup

technique must be used to bring

method performance within

acceptable limits.

and cleanup procedures and changes in
60

allowed. If an analytical technique other than

the technique specified in the EPA method is

used, then that technique must have a

specificity equal to or better than the

specificity of the techniques in EPA method

for the analytes of interest.