these waters, the quantity of effluent discharged has a strong effect 

on the instream dilution and therefore upon the RWC. At the 

extreme case of a stream that is 100 percent effluent, it is the effluent 

concentration rather than the effluent mass discharge that dictates 

the instream concentration. Therefore, EPA recommends that permit limits on both mass and concentration be specified for 

effluents discharging into waters with less than 100 fold dilution 

to ensure attainment of water quality standards. 

5.7.2 EmugytZtmsmdon 

Water quality-based permit limits by themselves do not provide any 

incentive to dischargers to reduce wastewater flows. The reverse is 

true; a more dilute effluent means water quality-based limits are 

more easily achieved. However, increased flow translates into increased power consumption for treatment facilities. Significant power 

usage stems from pumping and mixing of volumes of wastewater in 

treatment systems. If the volume of wastewater can be reduced, 

power consumption can be reduced and less fossil fuel burned. Such 

reductions can be expected to result in concomitant decreases in air 

pollution. 

Therefore, EPA recommends that flow reductions and energy savings 

be specifically encouraged where appropriate (usually in dilutions 

greater than 1OO:l) by allowing water quality-based permit limits to 

be mass-based and by allowing concentration-based limits to vary in 

accordance with flow reduction requirements. The permit also could 

include an energy savings analysis subject to approval by the permitting authority. 

5.7.3 lZWsi&afions intbelkwof~icd-wlfk Umits 

Metals 

Another common problem encountered in expressing permit limits 

occurs for metals. Some water quality standards express numeric 

criteria for metals in terms of the dissolved or acid soluble phase of 

the metal. NPDES regulations at 40 CFR 122.45(c) require permit 

limitations for metals to be expressed in terms of total recoverable 

metal unless (1) an effluent guideline requires the use of another 

form, (2) technology-based limits are established on a case-by-case 

basis, or (3) the approved analytical method measures only the 

dissolved form. 

Where State water quality standards are expressed directly as total or 

total recoverable metals, the permit limit can be established directly. 

Where the water quality standards are expressed as dissolved or acid 

soluble metal, the permit writer will need to reconcile the different 

expressions of metals when establishing the permit limits. Some 

State water quality standards implementation policies or procedures 

provide the requirements for this conversion. In instances where a 

State has no policy or procedure, the permit writer can take one of 

four approaches. First, the permit writer could assume no difference 

between the dissolved or acid soluble phases and the total recoverable phase. This is the most stringent approach and would be most 

appropriate in waters with low solids, where the discharged form of 

the metal was mostly in the dissolved phase, or where data to use the 

other options are unavailable. Second, the permit writer could 

develop a site-specific relationship between the phases of metals by 

developing a relationship through review of information on instream 

metal concentrations. This approach requires concurrent sampling 

of both metal phases during periods reflective of the environmental 

conditions used to determine the WL4. Third, the permit writer 

could use a relationship developed by EPA from national data; 

this relationship is described in the national guidance for determining WlAs for toxic metals in rivers. This relationship requires knowledge of instream concentrations of total suspended 

solids at the environmental conditions used to determine the 

WIA. Fourth, the permit writer could use a geochemical 

model, such as the equilibrium metal speciation model 

MINTEQA2 (see Chapter 4). However, the input data requirement of this model are equivalent to collecting site-specific 

data under Option 2. These options will be expressed in more 

detail in subsequent guidance issued by EPA. 

Updute: The Agency has issued “interim Guidance on Interpretotion and lmplementution Aquatic Life Criteria for Metals. ” See the 

update notice in front of this document for ovoilobility. 

Detection Level Limits 

A commonly encountered problem is the expression of calculated limits for specific chemicals where the concentration of 

the limit is below the analytical detection level for the pollutant 

of concern. This is particular’ true for pollutants that are toxic 

in extremely low concentrations or that bioaccumulate. 

The recommended approach for these situations is to include in Part 1 of the permit the appropriate permit limit 

derived from the water quality model and the WLA for the 

parameter of concern, regardless of the proximity of the 

limit to the analytical detection level. The limit also should 

contain an accompanying requirement indicating the specific 

analytical method that should be used for purposes of compliance monitoring. The requirement should indicate that any 

sample is analyzed in accordance with the specified method 

and found to be below the compliance level will be deemed to 

be in compliance with the permit limit unless other monitoring 

information (as discussed below) indicates a violation. Sample 

results reported at or above the compliance level should be 

reported as observed whereas samples below the compliance 

level should be reported as less than this level. 

The level of compliance cited in the permit must be clearly 

defined and quantifid. For most NPDES permitting situations, EPA recommends that the compliance level be defined in the permit as the minimum level (ML). The ML is 

the level at which the entire analytical system gives recognizable mass spectra and acceptable calibration points. 

This level corresponds to the lowest point at which the calibration curve is determined based on analyses for the pollutant of 

concern in a reagent water. The ML has been applied in 

determinations of pollutant measurements by gas chromatography combined with mass spectrometry. The concept of a 

minimum level recently was used in developing the Organic 

Chemicals, Plastics, and Synthetic Fibers effluent guidelines 

PI. 

The minimum level is not equivalent to the method detection 

level, which is defined in 40 CFR Part 136 Appendix 6 as the 

minimum concentration of a substance that can be measured 

and reported with 99-percent confidence that the analyte concentration is greater than zero and is determined from the analysis of a sample in a given matrix containing the analyte. EPA is 

not recommending use of the method detection level because 

quantitation at the method detection level is not as precise as at 

111 
- 

the ML. It is not similar to the practical quantitation limit (PQL), 

which is typically set as a specific (and sometimes arbitrary) 

multiple of the method detection level. Because the PQL has no 

one definition, EPA is not recommending its use in NPDES permitting. Nor is it similar to other terms such as the limit of detection, 

limit of quantitation, estimated quantitation limit, or instrument 

detection limit. 

The permitting authority may choose to specify another level at 

which compliance determinations are made. Where the permitting authority so chooses, the authority must be assured that the 

level is quantifiable, defensible, and close as possible to the permit 

level. 

Where water quality-based limits below analytical detection 

levels are placed in permits, EPA recommends that special 

conditions also be included in the permit to help ensure that 

the limits are being met and that excursions above water 

quality standards are not occurring. Examples of such special 

conditions include fish tissue collection and analyses, limits and/or 

monitoring requirements on internal waste streams, and limits 

and/or monitoring for surrogate parameters. This information 

can be used to help support reopening the permit to establish 

more stringent effluent limits if necessary. 

5.7.4 ConsMevatioa in the Use of wlrole Effhnt ToxMy 

lhifs 

Test Methods 

NPDES regulations at 40 CFR 122.44(i)(l)(iv) require that methods approved under 40 CFR Part 136 be used for compliance 

monitoring, and in the absence of an approved method, the 

permit must specijl the method to be used. The permit should 

also carefully consider any other case-specific aspects of the whole 

effluent toxicity test method that should be designated in the 

permit. Such aspects as the dilutions at which testing will be 

conducted, the different species to be used, the specific endpoints, the statistical procedures for analyzing the data, quality 

assurance, and other factors should be clearly stated as a permit 

condition to assure that the whole effluent toxicity testing that is 

performed to ascertain compliance with a limit or monitoring 

requirement is the test procedure the regulatory authority desires. 

In some instances, promulgated methodologies allow significant 

flexibility and choice in how the method is actually conducted. A 

simple reference to the methodology in the permit may not result 

in the test being conducted as intended. 

Units of Expression and Detection Levels 

The permit limit for toxicity itself and the detection levels, or 

sensitivity levels, associated with the various types of toxicity tests 

determine the type of monitoring requirement, which should be 

specified with the limit. It is a misconception to think, for example, that only acute toxicity tests should be used where the 

WLA for acute protection is used to derive the more limiting LTA 

or should always be used to monitor for the MDL. It is a similar 

misconception to think that only chronic tests should be used 

where chronic LTA is limiting or should always be used to monitor 

for the average monthly limit. The MDLs and AMLs are derived 

from the more limiting of the two LTAs. Therefore, either acute or 

chronic tests might apply to a given situation depending upon 

the test detection levels or test sensitivity. 

For example, a limit of 5 TU, (no observed effect concentration 

[NOEC] of 20 percent or greater) would require chronic toxicity 

testing where the ACR is 20 for that effluent, An acute test would 

not be sensitive enough to measure effluent toxicity in this instance, since 5 TU, would be equivalent to 0.25 TU,. Conversely, 

if the ACR was 2, then an acute test could be used because 5 TU, 

would be equal to 2.5 TUa. Generally, there is no reason to mix 

two types of monitoring requirements for the same limit when 

limits are derived from the most limiting LTA. Doing so will 

confuse the results and complicate assessments of average monthly 

limits where sampling frequency is greater than once per month. 

The acute toxicity test, when using an LCso as the test endpoint, 

has an upper sensitivity level of loo-percent effluent, or 1 .O TU,. 

If less than 50 percent of the test organisms die at loo-percent 

effluent an LCso cannot be determined from the test data, and 

the true LCso value for the effluent cannot be measured. In this 

situation, an acute test could still be used for compliance monitoring purposes but the endpoint would need to be changed to a 

greater level of sensitivity. The endpoint could be specified in 

terms of “no statistically significant difference in acute toxicity 

between 100 percent effluent sample and the control.” This is 

the most sensitive application of an acute test and could be used 

for monitoring compliance with a limit that, because of lack of 

available dilution, applies the EPA recommended acute criterion 

of 0.3 TU, at the end of the pipe. 

However, these tests would not accurately quantify any level of 

chronic toxicity present. For chronic testing, an effluent with an 

NOEC of greater than 100 percent presents a similar test sensitivity problem. An effluent with an NOEC of greater than 100 

percent contains less than 1.0 TU, and would meet the EPA 

recommended chronic criterion for toxicity at the edge of the 

mixing zone, if dilution were available, as well as at the end of the 

pipe if no dilution were available. 

Description of Limits 

When toxicity limits are used, additional description of the limit is 

required. The limit should be stated in Part 1 as “effluent toxicity” 

in the parameter column with “maximum TUs,” “minimum ATE 

[acute toxicity endpoint],” or “minimum NOEC” in parentheses 

underneath. The numerical values should be placed in the appropriate concentration column followed by TU or a percent sign. A 

footnote should direct the reader to Part 3 for specific requirements on how to conduct the tests. The description in Part 3 

should accomplish the following: 

l Explain how the limit is expressed (e.g., the limit is the 

minimum ATE expressed as percent effluent or the limit is 

the maximum TU,) 

l Specify the test species and the test methods for compliance monitoring purposes 

l Describe any special reporting or followup requirements 

(e.g., requirements to conduct a toxicity reduction evaluation). 

112 
- -~ -- 

The language in Part 3 should be modified as needed to suit the 

situation. The following example language is provided only for 

purposes of illustration: 

l “The effluent toxicity limit contained in Part 1 is the allowable chronic toxicity to the most sensitive of three test 

species. It is expressed as the allowable NOEC in percent 

effluent. The required test species and the procedures to 

follow are described in Short Term Methods for Estimating 

the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, EPAf600/4-89/001, March 1989.” 

l “The permittee shall conduct monitoring of effluent toxicity 

once per month. One 24-hour composite sample shall be 

collected and tested within 24 hours of collection. Results 

shall be reported as the NOEC. Any test that does not meet 

quality control requirements as described in the above 

referenced methods shall be repeated using a freshly collected sample as soon as practicable.” 

57.5 sekction of MoRiforillg freguencles 

There is no fixed guidance on establishment of monitoring frequencies. The decision on the monitoring frequency is casespecific and needs to consider a number of factors, including 

those listed below: 

l Type of treatment process, including retention time 

l Environmental significance and nature of the pollutant or 

pollutant parameter 

l Cost of monitoring relative to the discharger’s capabilities 

and benefit obtained 

l Compliance history 

l Number of monthly samples used in developing the permit 

limit 

l Effluent variability. 

Based upon an array of data analyzed for both individual chemicals and whole effluent toxicity, and independent of other considerations, EPA has observed that ideally 10 or more samples per 

month provides the greatest statistical likelihood that the average 

of the various monthly values will approach the true monthly LTA 

value. In practice, however, selection of monitoring frequencies 

will need to consider the previously mentioned factors and arrive 

at a reasonable compromise of the appropriate considerations. 

Permits require monitoring to establish whether a facility is discharging at a level that complies with the permit limits. All 

monitoring includes analytical variability. The true concentration 

in a sample can be higher or lower than the measured one due to 

this variability; however, there is no way to predict which way it 

will go. 

Historically, EPA has not directly considered analytical variability 

from monitoring methods when establishing permit limits. If the 

upper bound of the analytical variability was added to the limit, 

there would be a higher potential that the permit limit would fail 

to protect the wasteload allocation. This would not be consistent 

with 40 CfR 122.44(d)(l). On the other hand, if the lower bound 

of the analytical uncertainty was subtracted from the limit, there 

would be better assurance that the limit achieved the WLA. This 

approach could be overly conservative given the other factors 

used to develop permit limits. EPA believes that its recommended 

approach provides a balance between these two extremes. 

57.7 kMmksi~dhg 

CWA Section 402(o) establishes express statutory language prohibiting the relaxation of permit limits based on water quality. 

Under the statute, relaxation of water quality-based limits is permissible only if either the requirements of Sections 402(o)(2) or 

303(d)(4) are met. These two provisions constitute independent 

exceptions to the prohibition against relaxation of permit limits. tf 

either is met, relaxation is permissible. 

Relaxation of Water Quality-based Limits Under 

Section303(d)(4) 

Section 402(o)(l) prohibits the establishment of less stringent 

water quality-based effluent limitations “except in compliance 

with Section 303(d)(4).” Section 303(d)(4) has two parts: Paragraph (A), which applies to “nonattainment waters” and Paragraph (B), which applies to “attainment waters.” 

l Nonattainment waters: Section 303(d)(4)(A) allows establishment of less stringent water quality-based effluent limitations in a permit for discharge into a nonattainment 

water only if (1) the existing permit limitation must have 

been based on a total maximum daily load (TMDL) or other 

WLA established under Section 303, and (2) attainment of 

water quality standards must be assured. 

l Attainment waters: Section 303(d)(4)(8) allows establishment of less stringent water quality-based effluent limitations in a permit for discharge into an attained water as 

long as the revised permit limit is consistent with a State’s 

antidegradation policy. This is not restricted to limits based 

on a TMDL or WLA. 

Relaxation of Water Quality-based Limits Under 

Section 402 

Section 402(o)(2) also outlines exceptions to the general prohibition against establishment of less stringent water quality-based 

permit limits in a permit. Under Section 402(o)(2), the establishment of less stringent limits based on water quality may be 

allowed where: 

1) There have been material and substantial alterations or 

additions to the permitted facility which justify this relaxation. 

2) Good cause exists due to events beyond the permittee’s 

control (e.g., acts of God) and for which there is no reasonably available remedy. 

3) The permittee has installed and properly operated and 

maintained required treatment facilities but still has been 

unable to meet the permit limitations (relaxation may only 

be allowed to the treatment levels actually achieved). 

113 
4) New information (other than revised regulations, guidance, 

or test methods) justifies relaxation of water quality-based 

permit limitations. 

This last exception applies to water quality-based permit 

limitations only where the revised limitations result in a net 

reduction in pollutant loadings and are not the result of 

another discharger’s elimination or substantial reduction of 

its discharge for reasons unrelated to water quality (e.g., 

operation termination). 

Although Paragraph 402(o)(2) lists two additional exceptions, 

one for technical mistakes and mistakes of law and one for permit 

modifications or variances, the statute provides that these exceptions do not apply to water quality-based effluent limitations. As a 

result, these exceptions do not provide a basis for relaxing water 

quality-based limitations. 

Relaxation of Water Quality-Based Permit Conditions or Standards 

The provisions in Section 402(o) discussed previously only address the relaxation of effluent limits based on water quality. The 

relaxation of other permit conditions or standards based on water 

quality are governed by EPA’s existing antibacksliding regulations 

at 40 CfR 122,44(l)(l). Under these regulations when a permit is 

renewed or reissued, interim effluent limitations, standards, or 

conditions must be at least as stringent as the final effluent 

limitations, standards, or conditions in the previous permit “unless the circumstances on which the previous permit was based 

have materially and substantially changed since the time the 

permit was issued and would constitute cause for permit modiftcation...“. In other words, unless cause for permit modification is 

present, relaxed conditions or standards are not permissible. EPA 

regulations setting forth cause for permit modification can be 

found at 40 CFR 122.62. 

Restrictions of Backsliding 

Even if any of the backsliding exceptions outlined in the statute or 

regulations are applicable and met, Section 402(o)(3) acts as a 

floor and restricts the extent to which water quality-based permit 

limitations may be relaxed. Paragraph (o)(3) prohibits the relaxation of water quality-based permit limitations in all cases if there 

will be a violation of applicable effluent limitation guidelines or 

water quality standards, including antidegradation requirements. 

This requirement affirms existing provisions of the CWA that 

require permit limits, standards, and conditions to ensure comptiante with applicable technology-based limits and water quality 

standards. 

5.8 T'OXICITY IlEwlcTltM EVAUJATlWS 

Where monitoring indicates unacceptable effluent toxicity, one 

principal mechanism for bringing a discharger into compliance 

with a water quality-based whole effluent toxicity requirement is a 

toxicity reduction evaluation (TRE) [6]. The purpose of a TRE is to 

investigate the causes and to identify corrective actions for difficult effluent toxicity problems. The permitting authority may 

require that the permittee conduct a TRE in those cases where the 

discharger is unable to explain adequately and immediately correct exceedances of a whole effluent toxicity permit limit or 

requirement. 

A TRE is a site-specific study conducted in a stepwise process to 

narrow the search for effective control measures for effluent toxicity. TREs are designed to identify the causative agents of effluent 

toxicity, isolate the sources of the toxicity, evaluate the effectiveness of toxicity control options, and then confirm the reduction in 

effluent toxicity. The ultimate objective of a TRE is for the discharger to achieve the limits or permit requirements for effluent 

toxicity contained in the permit and thereby attain the water 

quality standards for receiving waters. 

The requirement for a permittee to conduct a TRE may be written 

into the special conditions section of a permit, which contains 

whole effluent toxicity limits. In some cases, the permit issuing 

authority may also use other legally binding mechanisms, including Section 308 letters, Administrative Orders, or Consent Decrees, to require a TRE. 

5.8.1 RE 8uMance aOeur#rrrls 

To assist permittees in conducting TREs and achieving compliance 

with whole effluent toxicity limits, EPA has developed a series of 

three guidance documents [6, 7, 81: 

1) Generalized Methodology for Conducting Industrial Toxicity 

Reduction Evaluations (EPAl600/2-88/070) 

2) Toxicity Reduction Evaluation Protocol for Municipal Wostewater Treatment Plants (EPA/600/2-88/062) 

3) Methods for Aquatic Toxicity identification Evaluations: 

Phase 1 Toxicity Characterization Procedures (EPA/600/3- 

88/034) 

Phase 2 Toxicity Identification Procedures (EPA/600/ 

3-88/035) 

Phase 3 Toxicity Confirmation Procedures (EPA/600/ 

3-881036). 

These guidance documents describe the methods and procedures for conducting TREs and Toxicity Identification Evaluations 

(TIES). They are based on the results of EPA’s continuing efforts in 

TRE methods research and case study applications. Separate TRE 

guidance has been developed for industrial dischargers and municipal wastewater treatment plants to better address the circumstances of each type of facility. Procedures for the characterization, identification, and confirmation of the causative agents of 

effluent acute toxicity have been developed and are described in a 

three-phased TIE methods manual. These TIE methods are applicable to both industrial and municipal effluents and are an integral part of the protocols for TREs described in the industrial and 

municipal TRE guidance documents. TIE methods using chronic 

toxicity tests for identifying toxicants will soon be developed and 

available in a draft guidance document. 

5.8.2 Ret- &mJ8chflulA%nwmgl7r& 

To ensure the successful completion of a TRE, the guidance 

documents recommend a systematic, stepwise approach that 

114 
eliminates the possible causes or sources of toxicity until a solution 

or control method is determined. The guidance documents 

discourage “playing hunches” or implementing extensive control 

measures solely on the basis of unsubstantiated conclusions (e.g., 

selecting and implementing a treatment plant upgrade without 

adequate information). Experience shows that unnecessary delays 

and expenditures in achieving the objective of the evaluation are 

avoided by building a sound scientific and engineering basis for 

selection of a control method. This can best be done by the 

logical interpretation of the information and data collected in a 

systematic approach to a TRE. The causes or control methods 

identified should then go through a confirmation stage. This is 

especially important in cases where the control method selected 

requires the construction of additional treatment. A flow chart, 

generalized from the guidance documents, for this approach to 

TREs is presented in Figure 5-l 0. The steps in this flow chart are 

summarized in the following discussion. 

Determination of TRE Objectives and Development of the TRE 

Plan 

Obviously, the success of any study is dependent on a clear 

understanding of what is to be achieved and how these objectives 

are to be demonstrated and measured. Typically, TRE objectives 

are set by the regulatory authority in terms of a toxicity test 

endpoint (ATE or chronic toxicity endpoint [CTE]) in order to 

I I 

TRE Regulatory 

Requirements 

r-l lnlorrnatlon and 

Data Acqulsltlon 

Facility Operation 

and Maintenance 

IdenUficatlon 

Control Method 

Selectctlon and 

Implemefltatlon 

FoHowup and 

Conflrmatlon 

I I 

meet a limit or permit condition. TRE plans should be submitted 

by the discharger as soon as possible. In some cases, this could be 

30 to 60 days following notification that a TRE is required. In 

other instances, this period could be longer. These plans are 

important for ensuring that the TRE objectives are well understood and that the TRE to be conducted is thorough and represents a reasonable effort to achieve the required reduction in 

effluent toxicity. An implementation schedule should also be 

developed describing the timeframe for completion of the specific 

components of the TRE plan by the required TRE completion 

date. This schedule should be submitted for review in conjunction with the TRE plan. EPA recommends that the TRE schedule 

should be set or approved by the regulatory agency. Approval 

of the schedule and the completion date should not imply approval of the TRE plan itself or the procedures and methods 

outlined in the plan. Instead, the TRE plan should only be 

reviewed and any comments provided to the permittee as needed. 

To assist in this review, Box 5-3 provides evaluation criteria for TRE 

plans. The permitting authority should review the TRE plan and 

inform the discharger of any apparent shortcomings or potential 

problems. The TRE should not be delayed pending completion of 

the review of the plan. The specified completion date for the TRE 

must still be met and the permittee should be expected to begin 

steps to investigate and alleviate the effluent toxicity as soon as 

possible following notification that a TRE is required. bring the 

course of the TRE, the regulatory agency should provide oversight, as time permits, to make the TRE as effective as possible. 

Evaluation of Existing Site-specific Information 

The next step involves the collection of any information and 

analytical data relevant to the effluent toxicity. The permittee 

should begin collecting and evaluating this information as soon as 

possible following notification that a TRE is required. In some 

cases, this step may be conducted concurrently with accelerated 

toxicity testing as part of the development of a TRE plan. For an 

industrial discharger, this part of the evaluation would include 

information such as plant and process information, influent and 

effluent physical and chemical monitoring data, effluent toxicity 

data, and material use. For a POlW, additional information, such 

as industrial waste survey applications, local limits compliance 

reports, and monitoring data, should be collected. This information is used to supplement the data generated in the later steps of 

the TRE and may be useful at that stage to point to potential 

sources or treatment options. 

Evaluation of Facility Operations and Maintenance 

Practices 

This part of the evaluation is performed in order to ascertain 

whether the facility is consistently well operated and whether the 

effluent toxicity is Ihe result of periodic treatment plant upsets, 

bypass, or some other operational deficiency that may be causing 

or contributing to the effluent toxicity. This part of the TRE should 

be initiated immediately after notification that a TRE is required. 

Alternatively, the permittee may begin to conduct this step at the 

same time that any accelerated toxicity testing is required. At 

both municipal and industrial facilities, this step would involve the 

evaluation of “housekeeping,” treatment system operation, and 

chemical use. In some cases, best management practices (BMPs) 

Figure 5-10. Generalized TRE Flow Chart 

115 
may be identified, which would improve operations and effluent 

quality. However, the effectiveness of BMPs in reducing effluent 

toxicity should be carefully confirmed, and it will usually be 

necessary to test a number of samples and perhaps to conduct 

Phase 1 of the TIE to develop this level of certainty. The results of 

this evaluation may lead to preliminary strategies for source reduction and pollution prevention, including spill or leak prevention, improvements in material handling and disposal practices, 

or substitution or re-use of a compound known to be highly toxic. 

Toxicity Identification Evaluation 

TIE procedures are performed in three phases: characterization, 

identification, and confirmation [7]. In each phase, aquatic organism toxicity tests are used to track toxicity at each step of the 

procedure. In most cases, these are abbreviated or shortened 

nature of the causative agents of effluent toxicity or toxicants is 

determined. This is done by conducting a battery of tests to 

characterize the physical/chemical characteristics of the toxicity: 

solubility, volatility, decomposability, complexibility, filterability, 

and sorbability. This information can then be used to decide 

which chemical analytical methods will to use in Phase 2 or it can 

be used to design treatability studies. 

The results of Phase 1 also may be used to provide additional 

confirmation of the effectiveness of any BMP that was implemented in the previous step of the TRE to reduce the effluent 

toxicity. This would require conducting at least one Phase 1 

analysis prior to implementation of the BMP (i.e., any source 

control method implemented as a result of the evaluation of 

facility operation and maintenance). The results of this analysis 

would then be compared with Phase 1 results from samples taken 

toxicity tests. In the toxicity characterization phase, the general after BMP implementation. 

Box 5-3. Evaluation Criteria for TRE Plans 

. Are the objectives or targets of the TRE stated clearly and accurately? 

. Are the schedule and milestones for accomplishing the tasks described in the study plan? 

. Are the final TRE report, progress reports, and meetings with the regulatory authority included as part 

of the schedule? 

. Are the approaches or methods to be used described to the extent possible prior to beginning the 

TRE? 

. Has available EPA guidance been used in designing the TRE and developing the TRE plan (or if other 

methods are proposed, are these sufficiently documented)? 

1 Does the TRE plan specify what results and data are to be included in the interim and final reports? 

l Does the TRE plan provide for arrangements for any inspections or visits to the facility or laboratory 

that are determined to be necessary by the regulatory authority? 

. Are the toxicity test methods and endpoints to be used described or referenced? 

. Does the approach described build on previous results and proceed by narrowing down the possibilities in a logical progression? 

. Does the plan provide for all test results to be analyzed and used to focus on the most effective 

approach for any subsequent source investigations, treatability studies, and control method evaluations? 

. Are optimization of existing plant/treatment operations and spill control programs part of the initial 

steps of the TRE? 

l Does the TRE plan allow a sufficient amount of time and appropriate level of effort for each of the 

components of the study plan? 

. Does the TIE use broad characterization steps and consider quantitative and qualitative effluent 

variability? 

. Is toxicity tracked with aquatic organism toxicity tests throughout the analyses? 

. Is the choice of toxicity tests for the TRE logical and will correlations be conducted if the species used 

are different from those used for routine biomonitoring? 

. Is the laboratory analytical capability and the expertise of the investigator broad enough to conduct 

the various components of the evaluation? 

116 
In Phase 2 of the TIE, the results of Phase 1 are built upon, and the 

TIE proceeds to chemical analyses designed to identify the specific 

chemicals causing effluent toxicity. In Phase 3, the identified 

toxicants are confirmed using a number of procedures, including 

correlation of toxicity with chemical concentration, spiking experiments, toxicity mass balance, and additional test species and 

their symptoms. 

The current version of the TIE methods uses acute toxicity tests to 

characterize and identify the toxicants. In some cases, these 

methods may also be used for TREs where the objective is to 

reduce chronic toxicity. In order for these methods to be applicable, however, there must be some measurable acute toxicity in 

the effluent samples that are to be characterized in Phase 1 and 

analyzed in Phase 2. If this approach is used, the appropriate 

chronic toxicity test, as specified in the TRE objectives and permit 

requirements, should then be used in the Phase 3 confirmation 

procedures. This will confirm that the toxicant identified using 

acute tests in Phases 1 and 2, are indeed causing the whole 

effluent chronic toxicity, which must be reduced. 

It is possible to use the methods and procedures described in the 

other components of the overall TRE with either acute or chronic 

toxicity tests. The fact that the previous version of the EPA TIE 

methods use acute toxicity tests should not be construed to mean 

that TREs cannot be required or conducted for the reduction of 

chronic toxicity. These methods provide additional tools to assist 

permittees in the reduction of whole effluent chronic toxicity. 

Phase 1 procedures that use chronic toxicity tests will soon be 

available in draft EPA guidance. These TIE methods are applicable 

to freshwater discharges to either saltwater or freshwater receiving waters. The use of these methods for saltwater receiving 

waters may require their adaption for use with marine test species 

or, preferably, an initial correlation of the recommended freshwater TIE test species to the marine species used for monitoring. 

Source Investigation 

Based on the results of the TIE, a decision is made on whether to 

conduct treatability studies on the final effluent and/or conduct a 

source investigation. A source investigation is most readily performed when the specific toxicants have been identified and 

influent samples can be analyzed for the presence of these compounds or when potential source streams can be selected for 

chemical analysis (based on the results of the initial data acquisition step). However, in some cases where the specific causative 

agents of effluent toxicity have not been identified in the TIE, it 

may be possible to conduct a source investigation by “treating” 

influent samples in bench-scale models of the facility treatment 

plant, measuring the toxicity of the treated sample and then 

tracking this toxicity to its source. 

Source investigations will lead to control methods, such as chemical substitution, process modification, treatment of process or 

influent streams (pretreatment), and possible elimination of the 

process. For POTWs, source investigations may lead to the development of local limits or to the requirement that an indirect 

discharger evaluate and control their effluent so as to reduce its 

toxicity and prevent passthrough at the POTW. The implementation of source control methods can effectively reduce effluent 

toxicity and also can avoid any cross-media transfer of pollutants 

to air or sludge, which may occur as a result of end of pipe 

treatment. Types of source control methods that have proven to 

be effective in reducing effluent toxicity are improvements in 

facility housekeeping, chemical substitution, process optimization, reclamation/reuse, and pretreatment. 

Toxicity Treatability Evaluation 

Toxicity treatability evaluations are conducted to identify possible 

treatment methods that can effectively reduce effluent toxicity 

and may involve modifications or additions to the existing system. 

Treatability studies generally use the same type of information on 

the nature of the chemicals to be removed as is generated by 

Phase 1 of the TIE. These treatability tests should be conducted 

on a bench-scale initially and then a pilot scale prior to construction of additional treatment or substantial modification of the 

existing plant. The use of these bench- and pilot-scale tests, 

coupled with aquatic organism toxicity tests, should be used to 

confirm the effectiveness of the treatment option. Confirmation 

of the results of treatability studies is equally important as it is for 

the TIE. Skipping this confirmation step is an invitation for 

unwarranted expense. 

Toxicity Control Method Selection and Implementation 

After the investigative steps of the TRE are completed, it is not 

unusual for a number of possible control options to have been 

identified. At this point, a site specific selection must be made by 

the discharger based on the technical and economic feasibility of 

the various alternatives. Following this selection, the toxicity 

control method is implemented or a compliance plan is submitted if construction of additional treatment requires a substantial 

amount of time. 

Followup and Confirmation 

After the control method is implemented and the final TRE report 

is submitted, the permitting agency should direct the permittee 

to conduct followup monitoring to confirm that the reduction in 

effluent toxicity is attained and maintained. Normally, this monitoring should follow an accelerated schedule, weekly or biweekly 

toxicity tests, for a period of 2 to 3 months to confirm the 

effectiveness of the controls implemented and the continued 

attainment of the TRE objective. This followup monitoring should 

use the same species as were specified for routine toxicity testing 

in the permit. The test endpoints of these toxicity tests should be 

the same as those which were calculated by the water qualitybased permit limit derivation procedure used when the permit 

was issued. Once the discharger has demonstrated the successful 

completion of the TRE, the permitting agency should direct the 

discharger to return to the routine permit monitoring schedule. 

5.8.3 l%wmstmcas Wmattting a TRE 

It is the responsibility of the permitting authority to determine if 

the permit limits and/or the State water quality criteria have been 

threatened or violated and to notify the permittee if a TRE is 

required. It is appropriate for the permitting authority to require 

additional toxicity testing following the initial exceedance or violation. This additional testing may precede notification that a TRE 

will be required or it may be considered as the initial part of the 

117 
TRE and be conducted simultaneously with TRE plan development and the evaluation of other existing site-specific information. 

It is important to recognize that the purpose of this additional 

toxicity testing is to determine the continued presence or absence 

of effluent toxicity and the magnitude of that toxicity. This 

information can then be used to determine the continued compliance or noncompliance with the limit or permit conditions for 

effluent toxicity. These tests do not serve to verify or confirm the 

initial test results from an earlier sample. Instead, the permit 

authority shall use the results of these tests to determine if a TRE or 

some other action is the appropriate response to the initial occurrence of toxicity. 

If the permit has a limit for whole effluent toxicity, then generally, 

the permit should not include any specific conditions for accelerated toxicity testing or for triggering a TRE or some other action 

(e.g., exceedances in two consecutive tests or exceedances in any 

three out of five tests). CWA Section 309 requires that any single 

violation of a permit limit may be subject to enforcement. The 

EPA Compliance Monitoring and Enforcement Strategy for Toxics 

Control (January 19, 1989, Appendix 8-4) states that, “Each 

exceedance of a directly enforceable whole effluent toxicity limit 

is of concern to the regulatory agency and therefore qualifies as 

meeting the VRAC [violation review action criterion] requiring 

professional review.” Accelerated monitoring should only be 

used to assist in this professional review to determine what, if any, 

enforcement response is necessary, including the need for the 

permittee to conduct a TRE. It will be necessary for the Region or 

State regulatory authority to determine this on a case-by-case 

basis. This must be done in a manner consistent with the priorities established in their respective toxics control strategies and 

permitting procedures. 

In situations where it is determined that accelerated testing is 

appropriate, a maximum of weekly tests for a minimum period of 

2 months is recommended. This would result in eight tests, plus 

the routine monitoring toxicity test that initially indicated the 

exceedence or violation, for a total of nine tests in the series. As a 

practical approach for determining if a TRE is an appropriate 

response, EPA recommends if toxicity is repeatedly or periodically present at levels above the effluent limits more than 20 

percent of the time, a TRE should be required. With toxicity 

present at this rate, the TRE protocols will be useful. 

In most cases, any one additional exceedance (beyond the initial 

routine monitoring toxicity test result) in the accelerated toxicity 

tests could result in notification of the permittee that a TRE is 

required. Exceptions to this guideline might include cases where 

the permittee is able to adequately demonstrate that the cause of 

the exceedances is known and corrective actions have been immediately implemented or cases where additional test quality 

assurance/quality control (QA/QC) is necessary or desirable. The 

submittal of QC fact sheets for self-biomonitoring (e.g., Appendix 

6-2) should always be recommended to avoid QA/QC problems. 

If the test results indicate that toxicity is not consistently or 

repeatedly present in the test series, previous discharge monitoring reports (DMRs) should be examined to ascertain if a recurrent 

problem exists. If the problem is recurrent, a TRE should be 

required, and the TRE plan should explain how the design of the 

evaluation will address this periodic or recurrent effluent toxicity 

problem. In these cases, more elaborate sampling design and 

influent or process stream monitoring may be needed. It should 

be expected that TREs conducted under these circumstances will 

probably require a more flexible schedule and perhaps additional 

time before the required completion date. 

If the accelerated testing and previous DMRs show the continued 

absence of effluent toxicity, then the initial exceedance would be 

considered an episodic event and a TRE should not be required. A 

TRE is not an appropriate response to a single, episodic effluent 

toxicity event (e.g., a spill or a plant upset). By conducting 

accelerated testing following a violation or exceedance of a permit condition, unnecessary TREs can be avoided. Similarly, conducting accelerated testing as part of the initial steps of a TRE will 

allow for the TRE to be ended in its very early stages if the toxicity 

is immediately controlled or determined to be episodic or nonrecurrent. By following the TRE guidance and incorporating accelerated testing into the TRE, unnecessary analyses and expense can 

be avoided. 

It also is important to note that for the practical purposes of 

conducting a TRE (as opposed to the purpose of determining if a 

TRE should be required or not), the magnitude of the effluent 

toxicity needed to conduct a TRE may be less than the magnitude 

or level set as the permit limit or permit monitoring condition. 

This is because if the limit or monitoring condition is water 

quality-based then some amount of dilution will usually be incorporated in determining the unacceptable level of effluent toxicity. 

In some cases, it may be possible for the TRE procedures to be 

carried out even if the toxicity does not actually exceed this 

permitted level. This will be the case as long as the effluent 

toxicity is periodically or consistently present in measurable 

amounts in samples of loo-percent effluent. 

It also is reasonable for a discharger to initiate a TRE prior to the 

establishment of a permit limit for toxicity if unacceptable levels of 

toxicity are found in the effluent through routine monitoring or 

through inspection and compliance sampling by the regulatory 

authority. Under these circumstances the regulatory authority 

will need to identify what constitutes unacceptable levels of toxicity since this will not be defined by a permit limit (see Chapter 3 

on determining the reasonable potential for excursions of water 

quality standards). It also is not unreasonable for the discharger 

to voluntarily initiate a TRE under these circumstances. 

There are a number of mechanisms that can be used to require a 

TRE. In most cases, the TRE should be required by a Section 308 

letter or by an enforcement action, such as a Section 309 Administrative Order or a Consent Decree. The permittee should receive 

notification from the permit authority of what response is required. This enables the permit authority to assess whether a TRE 

is the appropriate action to pursue. If effluent toxicity reappears 

following the successful completion of a TRE, then the permit 

authority should be able to review this type of situation to determine if an additional TRE is appropriate or if some other action is 

required. In general, when the permit is issued with whole 

effluent toxicity limits in Part 1 of the permit, TRE requirements 

should be used where necessary to bring the permittee into 

compliance with those limits. Box 5-4 provides example lan118 
guage for effluent toxicity limits, developed as part of the Whole 

Effluent Toxicity Basic Permitting Principles and Enforcement Strategy (Appendix B-4). 

Box 5-5 presents sample language for use in requiring TREs by a 

Section 308 letter or a Section 309 Order. This sample language, 

especially the reporting dates, should be tailored to fit the specific 

permittee. The completion date should be specified on a case-bycase basis. Factors to consider in setting this completion date 

include the type of facility, the variability of the effluent, and the 

previous compliance history. In order to conduct a TRE, reasonable timeframes are 6 to 18 months for an industrial discharger 

and 12 to 24 months for a municipal wastewater treatment plant. 

For POlWs, it may take longer to conduct a TRE due to lengthy 

government contracting procedures, large sewer collection systems, and less influent constituent control. It should be recognized that extensions to these initial timeframes may be granted if 

the progress reports demonstrate that this is warranted. In situations where reductions in chemical concentrations to meet chemical-specific limits are needed as well as reductions in effluent 

toxicity, the timeframes may be adjusted to enable those efforts 

to proceed simultaneously. 

Box 54. Model Permit Language for Effluent Toxicity Limits 

Part 1 .A. Final Effluent Limits and Monitoring Requirements 

During the period beginning on the effective date of this permit and lasting until the expiration date, the 

permittee is authorized to discharge in accordance with the following limits and monitoring requirements 

from the following outfall(s): 001. 

Effluent Characteristic Discharge Limit Concentration 

Reporting Daily Monthly 

Code/Units Parameter Maximum Average 

Monitoring Requirement 

Measurement Sample 

Frequency Type 

-TUc Toxicity 10.0 5.0 x/month composite 

The permittee shall use the toxicity testing and data assessment procedures described in Part 3.8 of this 

permit. 

Box 5-5. Example Language for Requiring Toxicity Reduction Evaluations 

The discharger shall demonstrate that effluent toxicity-based permit limits described in Part 1 .A. of the 

permit are being attained and maintained through the application of all reasonable treatment and/or 

source control measures. Upon identifying noncompliance with those limits the discharger shall initiate 

corrective actions according to the following schedule: 

Task Deadline 

1. Take all reasonable measures necessary to Within 24 hours 

reduce toxicity immediately. 

2. Submit a plan and schedule to attain continued Within 30 days 

compliance with the effluent toxicity-based permit 

limits in Part I.A.,where source of toxicity is known, 

if immediate compliance is not attained. 

3. Submit a TRE study plan detailing the toxicity Within 45 days 

eduction procedures to be employed where source is 

unknown and toxicity cannot be immediately controlled 

through operational changes. EPA’s Toxicity Reduction 

Procedures, Phases 1, 2, and 3 (EPA-600/3-8Bi034, 035, 

and 036) and TRE protocol for POTWs (EPA-600/2-88i062) 

shall be the basis for this plan and schedule. 

119 
Box 5-5. Example Language for Requiring Toxicity Reduction 

Evaluations (continued) 

4. Initiate TRE plan. Within 45 days 

5. Comply with approved TRE schedule. Immediately upon approval 

6. Submit results of the TRE, including summary of Per approved schedule 

findings, corrective actions required, and data generated. 

7. Implement TRE controls as described in the final report. On due date of final report 

per approved schedule 

8. Complete TRE implementation to meet permit limits Per approved schedule, but 

and conditions. in no case later than XX 

months from initial noncompliance. 

120 
CHAPTER 5

REFERENCE5 

1. Marr, J.K., and R.P. Canale. 1988. Load Allocation for Toxics 5. U.S. EPA. 1987. Development Document for Effluent CuideUsing Monte Carlo Techniques. /ourno/ WPCF 60(5):659- lines and Standards for the Organic Chemicals, Plastics and 

66. Synthetic fibers Point Source Cateqow, volumes 1 and 2; EPA 

2. Freedman, P.L., 1.F. Penderqast, C. Wilber, and S.C. Chanq. 440/l -87/009. - , 

1988. Seasonal Changes and Effluent Limits. )ouma/ WP<f 6. U.S. EPA. 1988. Toxicity Reductions Evaluation Protocol for 

60(3):317-23. Municipal Wastewater Treatment Plants. EPA/600/2-88/ 

3. Parkerton, T.F., S.M. Stewart, K.L. Dickson, J.H. Rodgers, and 062. 

F.Y. Saleh. 1989. Derivation of Site-Specific Water Quality 7. U.S. EPA. 1988. Methods for Aquatic Toxicity ldentificotion 

Criteria for Zinc: Implications for Wasteload Allocation. Evaluations: Phase 1, Toxicity Characterization Procedures 

Research journal WPCF 61(11 ,12):1636-44. (EPA/600/3-88/034); Phase 2, Toxicity identification Proce4. Shell Chemical Company NPDES Permit Nos. LAOO05762, 

LAOO50962, TXOO048663, Appeal No. 85-l 4, 85-15, 85 

dures (EPA/600/3-88/035); and Phase 3, Toxicity Confirmation Procedures (EPA/600/3-88i0360. 

16 before the Administrator,’ U.S. EPA. U.S. .EPA Judicial 8. U.S. EPA. 1988. Generalized Methodology for Conducting InOfficer decision, October 20, 1987. dustrio/ Toxicity Reduction Evaluations. EPAJ600/2-88/070. 

ADDlTlONAl REFERENCES 

Aitchinson, J., and J.A.C Brown. 1963. The Lognormal Distributions. London: Cambridge University Press. 

Cilliom, R.H., and D.R. Helse. 1986. Estimation of Distributional Parameters for Censored Trace Level Water Quality 

Data 1 and 2. Water Resources Research 22:135-55. 

Kahn, H.D., and M.B. Rubin. 1989. Use of Statistical Methods in Industrial Water Pollution Control Regulations in the 

United States. Environmental Monitoring and Assessment 

12:129-48. 

Shumway, R.H., A.S. Azari, and P. Johnson. 1989. Estimating Mean Concentrations Under Transformation for Environmental Data with Detection Limits. Technometrics 

31(3):347-56. 

121 
6. COMPLIANCE MONITORING AND ENFORCEMENT 

6.1 INTRODUCTION 

Once a water quality-based permit containing limitations and 

conditions to control effluent quality is issued, the permittee is 

responsible for attaining, monitoring, and maintaining compliance with the requirements of that National Pollutant Discharge 

Elimination System (NPDES) permit. Failure to comply with any 

requirements stated in the permit is a violation of the Clean Water 

Act (CWA). 

The Environmental Protection Agency (EPA) and authorized State 

agencies are responsible for tracking compliance with and enforcing NPDES permit requirements in the enforcement of the CWA. 

Section 308 of the CWA and equivalent State statutes enable the 

regulatory agency to verify compliance with permit conditions 

(including water quality-based toxics limitations and compliance 

schedules) by authorizing the agency to impose on permittees 

requirements for sampling and analysis, record-keeping, and reporting. Section 308 also authorizes access by EPA or State 

agencies to facilities and records for verifying compliance with 

permit conditions. All records associated with monitoring must 

be maintained by the facility and available for a 3-year inspection 

period in conformance with 40 CFR Part 122.41. 

The CWA establishes the authority to enforce water quality-based 

permit conditions. The ability to enforce water quality-based 

permit conditions, however, relies on well-written, clearly stated 

permits. The enforcement official must be familiar with the 

process by which permit requirements were derived, including 

the procedures used to determine the wasteload allocation based 

on applicable water quality standards and the procedures used to 

derive limitations from the wasteload allocation. 

6.2 PERMIT REQUIREMENTS 

The conditions that are to be included in NPDES permits are 

described in 40 CFR Part 122 Subpart C. In general, permits 

include effluent limitations, schedules of compliance, and accompanying reporting requirements. Permits should prescribe the 

self-monitoring procedures, frequency of analysis, sampling location and procedures, acceptable or required analytical techniques, 

and frequency of reporting. Permits often require that analytical 

methods referenced in 40 CFR 136 be used for analysis, but may 

specify methodology not included in Part 136 for pollutants with 

no approved methods or where the approved method is inappropriate for a particular permit limitation. Permits should define any 

effluent limitations and explain specific procedures for calculating 

averages of data if different from arithmetic averaging. Permits 

should identify what information must be retained by the permittee, and what data must be submitted to EPA or the State. Results 

from self-monitoring required by the permit are reported on 

discharge monitoring reports (DMRs) that generally are submitted monthly. Sampling and analysis that is done more frequently 

than required by the permit must be included in the DMR. 

6.3 COMPLIANCE MONITORING 

Since most of the routine information gathered in compliance 

monitoring results from permittee self-monitoring, quality assurance (QA) is as important as compliance with limits. It is essential 

that permittees develop and adhere to a QA plan consistent with 

the required monitoring and analyses. The permittee is responsible 

for maintaining data to demonstrate compliance with QA procedures established in the test methodology or as specified in the 

permit. 

The regulatory agency generally has three ways of determining 

compliance with an NPDES permit and assuring adequate QA: 

self-monitoring reports, DMR/QA results, and inspections. Each 

of these methods is discussed below. 

6.3.1 Self-monitoring Reports 

Self-monitoring reports provide much of the compliance data 

used by the regulatory authority in the review of permittee compliance. These reports include DMRs and reports of progress on 

compliance schedules. DMRs contain information on the sampling method, frequency and location, and analytical results of 

permittee self-monitoring. These data and data from progress 

reports on major schedule milestones must be entered into the 

Permit Compliance System (PCS), a computerized data base, by 

the State or EPA [1]. When the required data are entered into the 

system, PCS will automatically “flag” violations of permit limitations, 

compliance schedules, and reporting requirements. 

In order to detect any problems with the quality of the sample 

analysis, it is often desirable to obtain QA information with the 

self-monitoring data. For this reason, several States and Regions 

have developed additional QA forms to accompany permittee 

self-monitoring reports, This additional information may be required through the permit or through a Section 308 order. The 

QA data are compared to a reference QA data sheet that can be 

completed by the regulatory authority to indicate acceptable 

ranges of values for the required protocol. Appendix B-5 provides 

an example of a reference QA data sheet for a whole effluent 

toxicity test. Once completed, this QA data sheet can be included 

in the compliance file for quick reference by compliance personnel. 

It is important to note that poor QA is a violation if the permit 

explicitly specifies adequate QA or references an acceptable protocol with corresponding QA procedures. It also is important to 

note that the signatory’s certification of effluent data certifies 

123 
compliance with the specified protocols. Any problems with QA 

should be reported at the time of DMR submission and the testing 

repeated. 

6.3.2 Discharge Monitoring Report/Quality Assurance 

(DMR/QA) 

The DMR/QA program evaluates a permittee’s ability to analyze 

and report accurate data. This program is intended to improve 

overall laboratory analytical performance for self-monitoring data. 

Authority for requiring participation is granted in CWA Section 

308. In the DMR/QA program, permittees are required to analyze 

“blind” samples with constituents and concentrations that can be 

found in their industrial or municipal wastewaters. The permittees’ results are compared to the known content of the sample, 

and an evaluation of the reported data is sent to the permittees. 

Permittees are expected to use the same personnel and methods 

employed for reporting NPDES data to analyze the samples. 

Permittees are required to follow the instructions for reporting 

results and include a signed certification statement in accordance 

with 40 CFR 122.22. 

Regulatory agencies conduct followup investigations to address 

poor or incomplete DMR/QA results, failure to participate, or late 

submittal of DMR/QA results. DMR/QA performance results are 

compiled annually. 

In the past, only chemical-specific analyses were tested in the 

DMR/QA program. The Environmental Monitoring and Support 

Laboratory (EMSL) in Cincinnati has developed a reference toxicant 

DMR/QA sample for permittees with whole effluent toxicity 

monitoring requirements. National implementation is occurring 

in 1991. 

6.3.3 Inspections 

Inspections are conducted by the regulatory authority or its contractors to address specific violations or problems and to verify 

permittee compliance with permit conditions and QA procedures. 

Inspections may include reviewing records, inspecting treatment 

facilities, assessing progress with compliance schedules, evaluating 

laboratory facilities and performance, and collecting samples for 

analysis or “splitting” samples taken by the permittee for concurrent analyses. EPA has defined several types of inspections based 

on the tasks that are included in the NPDES Compliance inspection 

Manual[2]. Because regulatory authorities are expected to inspect 

all major permittees annually regardless of compliance status, 

nonsampling inspections (which are generally less resource-intensive) are encouraged for routine evaluation of permittee performance. However, sampling inspections are still encouraged to 

address permitting and enforcement priorities. For that reason, 

the regulatory agency must have the full capability to assess 

effluent compliance through inhouse resources or contract support. 

Inspections that focus on toxics control can provide useful information for water quality assessment and permit reissuance in 

addition to compliance data. Procedures for inspecting facilities 

with toxicity testing requirements and measuring effluent toxicity 

are detailed in the NPDES Compliance inspection Manual, Chapter 

7[2]. 

6.4 VIOLATION REVIEW 

Review of permittee self-monitoring data to determine appropriate enforcement response generally involves a two-tiered review. 

The first tier is a preliminary review for timely, complete data that 

indicates compliance with permit requirements. Minor violations 

of requirements are often handled through informal phone calls 

or warning letters that do not require extensive review or oversight. As violations increase in magnitude, duration, or frequency, 

they generally are assigned to personnel who are responsible for 

the second-tier review (determining what enforcement action, if 

any, is appropriate). The guidelines for this process are presented 

in the Enforcement Management System (EMS) [3], but the basic 

concepts of responsible compliance tracking of water qualitybased requirements are discussed below. Section 6.5 discusses 

the enforcement decision process. 

When the initial review of effluent monitoring data indicates that 

unacceptable analytical methods were used by a permittee or its 

contract laboratory, the results should be assigned for review by 

personnel qualified to determine the significance of the results. If 

the monitoring is insufficient to determine compliance with effluent limitations, a warning letter or Section 308 letter requiring 

that the tests be repeated using acceptable procedures would be 

an appropriate response. 

Tracking a permit or Section 308 letter that contains “monitor 

only” requirements requires both a compliance review (e.g., to 

determine if results of acceptable quality were submitted on 

time), and an action review (e.g., to determine if the permit 

should be modified or re-issued to include a limitation). This 

second review should be assigned to personnel who are qualified 

to make this regulatory decision. 

In addition to the guidelines for reviewing monitoring data in the 

absence of a specific effluent limitation, EPA also has recommended 

a criterion for determining which effluent violations must be assigned for review by a professional who will determine if a formal 

enforcement action is needed, or if a phone call, warning letter, or 

Section 308 letter is more appropriate. These criteria are known 

as the Violation Review Action Criteria and are listed in the EMS. 

In the case of a whole effluent toxicity limitation, any violation 

must be reviewed by a qualified professional responsible for the 

enforcement decision. EPA makes this recommendation to ensure 

that adequate attention is given to QA and to ensure that additional 

testing is required if permitted testing frequency is less than once 

per month. 

In the case of a violation of a chemical-specific permit limitation, 

EPA recommends that monthly average limitation violations be 

reviewed by a professional for potential enforcement response 

whenever two or more violations occur in a 6-month period. 

Seven-day average and daily maximum violations should likewise 

be reviewed if a minimum of two or four, respectively, occur 

during the course of 1 month. Although there is no delineation 

between technology-based versus water quality-based limitations 

in these Violation Review Action Criteria, Regions and States may 

wish to adopt a criteria of “any violation” for all water quality124 
..-_ 

based, chemical-specific limitations as these criteria are solely to 

determine the level of review and do not prescribe enforcement 

action. 

6.5 EWFORCEMENT 

Effective enforcement of toxic controls depends upon clearly 

expressed requirements in NPDES permits. These controls are 

generally in the form of numeric limits on specific toxic chemicals 

or whole effluent toxicity and schedules to initiate construction or 

other compliance measures. 

Exceeding a permit limitation is a violation subject to enforcement. Some members of the regulated community have expressed 

concerns that single violations of stringent water quality-based 

limitations will result in unreasonable enforcement actions. EPA’s 

guidance outlines a systematic review of all violations to determine 

the appropriate level of response. This guidance generally suggests 

an informal response for minor or infrequent violations, escalating 

to formal enforcement and perhaps penalties for more frequent 

and environmentally harmful violations. 

In evaluating appropriate response to violations, EPA’s “Enforcement Response Guide” of the EMS should be used for guidelines 

on the minimum acceptable response [3]. 

Further guidance on addressing violations of whole effluent toxicity 

limitations in particular is presented in the Compliance Monitoring 

and Enforcement Strategy for Toxics Control [4] (see Appendix t3- 

4). This strategy expects that all available avenues to compliance 

will be explored by the permittee, that the treatment facility is 

designed, constructed, maintained, and operated to achieve all 

water quality-based, chemical-specific or best available technology/ 

secondary treatment limitations, that chemical or process substitutions have been attempted and pretreatment explored, and 

that, in the case of publicly owned treatment works (POTWs), 

pretreatment program requirements and local limits have been 

established and enforced. The strategy further expects that the 

permittee will pursue a Toxicity Reduction Evaluation (TRE) as 

discussed in Chapter 5 in compliance with enforcement requirements or under its own initiative. If all of these expectations have 

been met and the facility is unsuccessful in identifying the cause, 

source, or treatability of toxicity despite making good-faith efforts 

to do so, the strategy allows for relief from civil penalties. The 

underlying responsibility to achieve compliance with the permit 

limitation remains in effect. 

Some members of the regulated community have requested EPA 

and several State agencies to define more clearly enforcement 

discretion with respect to violations of whole effluent toxicity 

limitations. To define enforcement discretion would in effect 

make it no longer discretionary. Furthermore, the purpose of 

such guidance would be questionable as individual enforcement 

responses by EPA and the States are open to review by the public 

and the courts. In lieu of such additional guidance on enforcement discretion, it is recommended that Regions and States 

adhere to the principles presented in the EMS, the strategy, and in 

this document. 

EPA also has developed a policy [S] on the assessment of appropriate civil penalties in both administrative and civil judicial actions in response to any CWA violation. This policy bases the 

penalty amount on the seriousness of the violation, the economic 

benefit enjoyed as a result of delayed compliance, any history of 

such violations, any good-faith efforts to comply, and the violator’s 

ability to pay. In no instance can this calculated penalty exceed 

the statutory maximum penalties defined in CWA Section 309. 

If any violation occurs, the permittee has the responsibility of 

informing the regulatory agency. If the violation potentially 

endangers health or the environment, the violation must be 

verbally reported to the regulated agency within 24 hours and the 

permittee must submit a noncompliance report within 5 days of 

violation detection. If there is no danger to health or the environment, the written report must be submitted at the time 

monitoring reports are submitted. These reports must include a 

description of the violation, its cause, the period of noncompliance, 

and if the noncompliance has not been corrected, the anticipated 

time when compliance will be achieved. 

As with other NPDES permit limitation violations, violation of a 

water quality-based toxics limit should prompt immediate action 

on the part of the permittee. Permittee response should include 

evaluation of the cause of the violation, correction of operational 

deficiencies or improvement of treatment efficiency, and any 

other initial steps necessary to resolve the violation and mitigate 

the environmental effects. These immediate investigatory and 

corrective steps also should provide information that may be used 

in developing a compliance schedule if the violation is not resolved 

quickly. 

When a water quality-based toxicity limit is violated, the regulatory 

agency may require additional monitoring to determine the frequency and duration of the violation. If the permit limit is not met 

quickly through improved housekeeping, operation, or raw waste 

control (e.g., POW enforcement of pretreatment requirements, 

or chemical substitution by industries), requiring a TRE as discussed 

in Chapter 5 may be appropriate. Where toxicity-based limitations 

are in effect, the enforcement response must require expeditious 

compliance with the limit. 

Available enforcement mechanisms include Section 308 orders, 

Section 309 Administrative Orders, Administrative Penalty Orders 

with Administrative Orders, or judicial action. Enforcement action 

must be tailored to the specific violation and type of remedial 

action required. Enforcement actions must be worded carefully 

so that they clearly are understood, easily tracked, and expeditiously 

enforced. 

Violating limitations of pollutants at concentrations that pose a 

threat to human health should receive immediate enforcement 

attention to prompt rapid resolution of the noncompliance. The 

regulatory agency should consider the pollutant concentration, 

exposure route, and whether or not the pollutant exhibits a 

threshold response in determining if a schedule may be allowed. 

Immediate injunctive relief (such as a temporary restraining order 

or preliminary injunction) should be sought when necessary to 

protect public water supplies and fish and sheltfish areas from 

imminent or substantial impairment. 

125 
6.6 REPORTlWGOFVlCHAllOS 

The regulatory authority is responsible for reporting to the public 

on permittees in violation. Reporting requirements for the Quarterly Noncompliance Report (QNCR) of major permittees in violation of their NPDES permits are established in 40 CFR 123.45. 

Reporting of violations of water quality-based monitoring, limitations, schedules, and reporting requirements by major facilities 

must be consistent with 40 CfR 123.45. Violations of permit or 

enforcement order conditions by major permittees must be reported as follows [6]: 

l Effluent violations (chemical-specific and whole effluent toxicity) must be reported on the QNCR if the violation has the . 

potential to have caused a water quality problem (40 Cf!7 

123.45(a)(z)(iii)(A)(l)). 

l Chemical-specific toxic permit limit violations must be reported on the QNCR if two or more monthly average 

measurements in a 6-month period exceed the limit by a 

l 

factor of 1.2 for a Group I parameter or 1.4 for a Group II 

parameter as defined in the Regulation, or if four or more 

monthly average measurements in a 6-month period exceed the limit by any amount (40 CFR 123.45(a)(2)(ii)(C)). 

Any violation during the quarter of an interim monthly 

average chemical-specific toxic limit established in an administrative order or court order/consent decree must be 

reported on the QNCR (40 CFR 123.45(a)(2)(ii)(A)). (Note: 

Whole effluent toxicity is not characterized as a Group I or 

Group II parameter, and as such, must be evaluated on a 

professional judgement basis under 40 CFR 

123.4S(a)(2)(iii)(A)(l).) 

Compliance schedule milestones that are not met within 90 

days of the scheduled date must be reported on the QNCR 

(40 CFR 123.45(a)(Z)(ii)(B)). 

Failure to submit a report within 30 days of the due date 

must be reported on the QNCR (40 CFR 123.45(a)(Z)(ii)(D)). 

126 
CHAPTER 6 

REFERENCE6 

1. Jensen, L.]. Permit Compliance System (PCS) Policy Statement. 

2. NPDES Compliance Inspection Manual, May 1988. 

3. Enforcement Management System for the National Pollutant 

Discharge Elimination System, September 1986. 

4. Hanmer, R.W. 1989. Who/e Effluent Toxicity Basic Permitting 

Principles and Enforcement Strategy. 

5. Jensen, L.J. 1986. C/eon Water Act Penalty Policy for Civil 

Settlement Negotiations. 

6. Hanmer, R.W. 1986. Guidance for Prepurotion of Quarterly 

and Semi-Annual Noncompliance Reports. 

127 
7. CASE EXAMPLES 

7.1 INTRODUCTION 

This chapter presents examples of the development of water 

quality-based discharge limits to illustrate the integration of the 

guidance of the previous chapters. There are three examples: an 

industrial discharge with ample dilution, a publicly owned treatment works (POTW) with moderate dilution, and the combination of an industrial facility and a POTW discharge to the same 

reach. 

7.2 CASE:1 INDUSTRIAL DISCHARGE 

The first example is the Jaybird Corporation, a metal finishing 

firm. The NPDES permit for the facility is about to expire, and the 

corporation has submitted an application for a new permit. The 

example shows the steps that a permitting authority would take 

to determine if a water quality-based effluent limit is necessary 

and then to establish such a limit. The example also illustrates 

when best available technology (BAT) limits are applied instead of 

water quality-based limits, the use of human health criteria, and 

the variations in the limits derived by different wasteload allocation methods. 

• 

• 

• 

7.2.1 General Site Description and Information 

The Jaybird Corporation facility discharges into the Locapunct 

River. The river is approximately 60 miles long and its banks are 

occupied by small towns separated by woodland and farmland. 

The river is classified by the State in the water quality standards as 

having designated uses of a fish habitat, primary contact recreation, and a drinking water supply. For these uses, the State has 

adopted the federal water quality criteria into the water quality 

standards to protect aquatic life and human health. The State 

standards also includes a narrative criterion of “no toxics in toxic 

amounts” for other toxic materials. 

Water quality monitoring indicates some infrequent excursions 

above water quality criterion for copper and nickel. These pollutants have been found in measurable quantities in the effluents of 

several facilities. 

The Jaybird Corporation is a metal finishing facility that specializes 

in copper plating of lead shells for a nearby military installation, 

As a metal finisher, the Jaybird Corporation is relatively small with 

a discharge of 0.034 cfs (0.022 mgd). The effluent at the Jaybird 

Corporation is treated by precipitation and settles before discharge through a multiport diffuser. The corporation is subject to 

BAT and best practicable technology (BPT) effluent limits for the 

metal finishing industry. 

7.2.2 Effluent Characterization for Specific Chemicals 

The permitting authority has adopted a procedure in which pollutants concentrations in each facility are evaluated for the potential to cause, have the reasonable potential to cause, or contribute 

to an excursion of the water quality standards. The authority used 

the effluent characterization process for specific chemicals described in Chapter 3 in this evaluation. In general, the procedures 

are designed to determine which pollutants are of concern and 

which require effluent limits. 

Step 1: Identify Pollutants of Concern 

Data were obtained from a number of sources to identify and 

quantify the pollutants of concern in the Jaybird Corporation 

effluent: 

Effluent chemical concentrations were taken from the Permit Application Form 2C, Discharge Monitoring Reports 

(DMRs), EPA’s Permit Compliance System (PCS), and permit files. 

EPA’s STORET data base was used to obtain U.S. Geological 

Survey flow data and ambient monitoring data for the river. 

BAT limits for the metal finishing industry were obtained 

from 40 CFR 433 Subpart A. 

The permitting authority noticed in review of these data that the 

information in Form 2C replicated the information in the DMRs, 

and therefore decided to use the DMR data as the primary basis 

for characterizing the effluent. These data for toxicants DMRs are 

shown in Table 7-1. For those parameters currently not covered 

by the permit, Form 2C data indicated that pollutant concentrations were below detection limits. The permitting authority requested information from the facility showing the detection levels 

used; these levels were consistent with the detection levels listed 

in the National Pollutant Discharge Elimination System (NPDES) 

regulations at 40 CFR 136. 

The effluent from the Jaybird Corporation is regulated by the 

Metal Finishing Point Source Category effluent guidelines at 40 

CFR 433 Subpart A. These guidelines regulate the following toxic 

pollutants: cadmium, chromium, copper, cyanide, lead, nickel, 

silver, zinc, and total toxic organics. 

Although these parameters were regulated at the Jaybird Corporation, the only toxic pollutants evident in the discharge were 

lead, copper, and nickel. The facility’s treatment system reduced 

concentrations of other pollutants to below detection. 

Step 2: Determine the RAC, CMC, and CCC for Pollutants of 

Concern 

The State has adopted numeric water quality criteria for acute 

toxicity (criterion maximum concentration [CMC]), chronic toxicity (criterion continuous concentration [CCC)), and protection of 

human health (reference ambient concentration [RAC]). The 

water quality standards present the CMC and CCC criteria as 

equations based on ambient hardness concentrations. The standards require that the 85th percentile lowest hardness be used. 

This value is 100 mg/l as CaC03 for the Locapunct River. 

129 
Table 7-1. Effluent Data for the Jaybird Corporation 

n 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

Copper Lead Nickel Toxicity 

μg/l μg/l μg/l TUC 

1,317 187 223 5 

1,092 230 261 10 

1,073 258 464 5 

1,059 423 341 20 

1,072 227 369 

1,677 275 1,058 

2,664 364 199 

1,058 170 259 

3,439 259 437 

6,596 264 773 

1,211 267 300 

1,082 175 356 

Mean 1,945 258 420 10 

SD 1,650 74 252 7.1 

CV 0.8 0.3 0.6 0.7 

Max 6,596 423 1,058 20 

Min 1,058 170 199 5 

N 12 12 12 4 

Source: DMR data for chemicals; 308 request for whole effluentoxicity. Notes: 

Metals reported as total recoverable metals; toxicity reported in chronic toxic 

units (100/NOEC). The permittee did not use a geometric dilution series for the toxicity tests. The 

results are the highestoxic units for any of the test organisms used. 

The aquatic toxicity criteria for metals in the standards are expressed as the acid soluble form of the metal. The State has 

adopted a ratio to express the acid soluble form of metals as the 

total recoverable form for the purposes of developing NPDES 

permit limits. This ratio is based on historical data that the State 

has collected for rivers in the basin where the Locapunct lies. The 

values of the ratio are 0.35 for lead, 0.70 for copper, and 0.85 for 

nickel. The standards consider the criteria for human health 

protection to be in the total recoverable form of the metal. 

Based on the hardness and acid soluble-to-total recoverable ratios, the applicable state water quality criteria are the following: 

Pollutant 

Lead 

Copper 

Nickel 

CCC CMC RAC 

μg/l μg/l μg/l 

9.1 235 50 

17.1 25.7 NA 

188 1,647 13.4 

Step 3: Determine Dilution for Aquatic life and Human Health 

Impacts 

The State water quality standards require that compliance with 

water quality criteria be achieved at the edge of the mixing zone. 

The standards specify the minimum dilution at which the criteria 

apply. These are the 7Q10 flow for the CCC, the 1Q10 flow for 

the CMC, and the harmonic mean flow for human health criteria 

(RAC). The U.S. Geological Survey operates a gaging station on 

the river; the flow statistics were calculated using the data from 

this station: 

• Harmonic mean flow = 38.0 cfs 

• 7Q10flow = 13.0 cfs 

• 1Q10 flow = 10.1 cfs. 

The facility provided a study of the outfall that showed that the 

multiport diffuser quickly achieved complete mixing across the 

width of the river. Dilution at the edge of the mixing zone could 

therefore be characterized by the complete mixing equation: 

C = (CemQe + CsQs/(Qe + Qs) 

where 

C = the receiving water concentration 

Cem = the maximum effluent concentration 

Qe = theeffluent flow 

Cs = the receiving water background concentration 

Qs = the appropriate receiving water flow. 

Step 4: Determine Reasonable Potential for Excursions 

To determine if the facility discharge was expected to cause or 

have the reasonable potential to cause the CMC, CCC, or RAC to 

be exceeded in the receiving water, the maximum receiving 

water concentration of each pollutant was first compared to the 

appropriate receiving water criterion. If the criteria were exceeded, then this was considered evidence that a water qualitybased limitation must be developed. 

Maximum expected concentrations were calculated using the 

average effluent flow, maximum effluent concentrations, background receiving water concentrations, and the relevant receiving water flow: the 1Q10 for the CMC, the 7Q10 for the CCC, or 

the harmonic mean for the RAC. The background receiving water 

concentrations for total recoverable metals were obtained from 

STORET data: 

Lead 1.6 μg/l 

Copper 4.8 μg/l 

Nickel 13.2 μg/l 

The maximum effluent concentration was estimated using the 

statistical approach in Chapter 3. There were 12 concentrations of 

each metal reported in the DMRs. For lead, these concentrations 

had a maximum value of 423 μg/l, an arithmetic mean of 258 μg/ 

I, an arithmetic standard deviation of 74, and an arithmetic 

coefficient of variation of 74/258, or 0.3. This coefficient of 

variation and the number of observations determined which multiplier was selected from Table 3-1. In this case, the multiplier 

value for 12 observations and a CV of 0.3 was interpolated from 

the values for 12 observations and CVs of 0.2 and 0.4. The 99th 

percentile multiplier was estimated to be 1.7. Similar calculations 

were conducted for copper (multiplier of 2.8) and nickel (multiplier of 3.7). 

130 
The receiving water concentration for lead for comparison with 

the CCC was calculated using data from Table 7-1: 

C = I(1.7 x 423 us/l x 0.034 cfs) + (1.6 us/l x 13 cfsjj 

(0.034 cfs + 13 cfs) 

= 3.5 pg/l 

where 

13cfs = the receiving water flow at 7410 

0.034 cfs = the mean effluent flow 

423 ug/l = the maximum effluent concentration 

1.7 = the statistical effluent multiplier to estimate the 

99th percentile concentration 

1.6 ug/l = the background receiving water concentration. 

The value of the calculated receiving water concentration, 

3.5 ug/l, was less than the chronic water quality standard of 9.1 

Pg/l for lead, and therefore there is no reasonable potential for the 

CCC to be exceeded. 

Using the effluent data presented in Table 7-1, the receiving water 

concentration is compared to the CMC as: 

C = I(1.7 x 423 us/l x 0.034 cfs) + (1.6 us/l x 10.1 cfs)] 

(0.034 cfs + 10.1 cfs) 

= 4.0 fig/l 

where 10.1 is the receiving water 1 QlO flow and the other values 

are identical to those for the CCC comparison. The resulting 

concentration of 4.0 ug/l was less than the acute standard of 234 

pg/l for lead. There is no reasonable potential for the CMC to be 

exceeded. 

For human health criterion evaluation, the receiving water concentration for compared to the RAC was calculated as: 

C = r(l.7 x 423 us/l x 0.034 cfs) + (1.6 us/l x 38 cfsIJ 

(0.034 cfs + 38 cfs) 

= 2.2 ug/l 

where 38 cfs is the harmonic mean flow and other values are the 

same as above. This value was less than the human heath criteria 

value of SO Pg/l for lead, so there is no reasonable potential for the 

RAC to be exceeded. 

Similar calculations were done for copper and nickel: 

Copper 

ccc 

CMC 

Nickel 

ccc 

CMC 

RAC 

Criterion Receiving Water 

cPg/l) Concentration @g/l) 

17.1 22.0 

25.7 26.9 

188 15.9 

1,647 16.6 

13.4 14.1 

The effluent characterization showed the reasonable potential for 

excursions above the CCC for copper and above the RAC for 

nickel. Therefore, permit limits are necessary for these two pollutants. 

7.2.3 E#oont Chwacto?lzotlon far mlo ERhnwt rO%iCifJ’ 

Whole effluent toxicity also was evaluated since there was a 

potential for excursions above the narrative water quality criterion 

due to the combination of effluent toxicants with other toxicants 

in the receiving water and in the effluent but below the detection 

level. The procedures used below follow those presented schematically in Figure 3-2, Chapter 3. 

Step 1: Dilution Determination 

The initial dilution determination was used to establish the types 

of toxicity tests that are conducted to characterize the effluent. 

The dilution at the low-flow characteristics for the facility is the 

following: 

At the 7Q10, dilution = (0.034 cfs + 13 cfs)/0.034 cfs 

= 383 

At the 1 Ql 0, dilution = (0.034 cfs + 10.1 cfs)/O.O34 cfs 

= 298. 

Step 2: Conduct Toxicity Testing 

EPA recommends that a discharger having a dilution between 

100 and 1,000 be required to conduct either chronic or acute 

toxicity testing. The permitting authority decided to require 

chronic testing but required the permittee to report the test 

results at the 48-hour endpoint so that acute toxicity could be 

measured. One year before the permit was due to expire, the 

permitting authority requested, under the authority of the Clean 

Water Act (CWA) Section 308, that the permittee test his effluent 

for toxicity to provide effluent information in order to write the 

next NPDES permit. In this case, the permitting authority specified that the discharger submit quarterly chronic toxicity data for 

1 year using the EPA toxicity tests for Selenostrvm, Cerioduphnia, 

and Pimephales. The permitting authority also specified that upstream ambient water be used as the diluent in the tests so as to 

allow the tests to measure additive effects from ambient toxics. In 

response to the Section 308 request, the discharger submitted 

the whole effluent toxicity data shown in Table 7-l. 

Step 3: Determine Reasonable Potential for Excursions 

The State interprets its narrative criteria for whole effluent toxicity 

to require that the technical support document recommendations of 0.3 TU, and 1 .O TU, be used as numeric values for acute 

and chronic toxicity, respectively. In accordance with the State 

standards, the CMC applies under the 1 Ql 0 flow and the CCC 

applies under the 7QlO flow. 

The determination of exceedance of the CMC or the CCC was 

simplified by the way in which the tests were conducted. Since 

the upstream ambient water was used as a diluent, the test results 

131 
already include an assessment of contributions from background 

toxicity. Therefore, the upstream receiving water concentration 

was set to zero. 

The maximum effluent concentration was again estimated by 

using the statistical approach in Chapter 3. As shown in Table 7- 

1, there were four observations of whole effluent toxicity. Based 

on the guidance of Box 3-4, these are insufficient to determine 

the CV accurately; therefore, the default CV of 0.6 was used. The 

effluent multiplier of 4.7 was obtained from Table 3-l using the 

number of observations, the CV, and the 99percent probability 

basis. 

The receiving water concentration for chronic toxicity for comparison with the CCC was calculated using data from Table 7-l : 

C = (4.7 x 20 TU, x 0.034 cfs) + (0 TU, x 13 cfs)] 

(0.034 cfs + 13 cfs) 

= 0.25 TU, 

where 

13cfs = the receiving water flow at 7410 

0.034 cfs = the mean effluent flow 

4.7 = the statistical effluent multiplier 

20 TU, = the maximum effluent concentration. 

The value of the calculated receiving water concentration, 0.25 

TU,, was less than the chronic water quality standard of 1 .O TU,, 

and therefore there is no reasonable potential for the CCC to be 

exceeded. 

To calculate the receiving water concentration for acute toxicity, 

the permitting authority first converted the chronic toxicity data 

into equivalent acute toxicity units by applying the acute-tochronic ratio (ACR) of 5 obtained from the monitoring data. The 

receiving water concentration for acute toxicity was then calculated: 

C = [(4.7 x 20 TU, / 5 ACR x 0.034 cfs) + (0 TU, x 10.1 cfs)] 

(0.034 cfs + 10.1 cfs) 

= 0.06 TU, 

where 10.1 cfs is the receiving water flow at 1 Ql 0, 5 is the acute 

to chronic ratio, and the other values are the same as above. The 

calculated value of 0.06 TU, is below the criterion of 0.3 TU,; 

therefore, there is no reasonable potential for the CMC to be 

exceeded. Since there was no reasonable potential for exceedances 

above either the acute or chronic criterion, permit limits were not 

developed for whole effluent toxicity. 

7.2.4 &!temhe wisstaa Aw8tl~ 

The wasteload allocation @VIA) was used to determine the level 

of effluent concentration that would comply with water quality 

standards in the receiving waters. A WlA will only be determined 

for those parameters that have a reasonable potential to cause 

exceedances of water quality standards. Therefore, WLAs were 

determined for copper and nickel. Since there was no reasonable 

potential for excursions above the CMC or CCC for nickel, only 

the WLA for human health was calculated. 

To determine WLAs, the numeric criteria in the water quality 

standards and background concentrations were used to calculate effluent concentrations that would result in compliance 

with those standards. The calculation of WlAs used receiving 

water flows that were appropriate to each standard: chronic 

WLAs were calculated using the 7410 flow, acute WlAs were 

calculated using the 1 QlO flow, and human health WLAs were 

calculated using the harmonic mean flow. Since the effluent 

was mixed rapidly by the multiport diffuser, the complete mix 

equation was used: 

MA = WQC x (Q + QJ - Q&I/Q, 

where 

Qe = the effluent flow 

QS = the receiving water flow 

cs = the background receiving water concentration 

WQC = the water quality criterion. 

The chronic and acute WLA for copper were calculated at the 

7410 and 1 Ql 0 flows, respectively: 

WLA, = [17.1 ug/l x (0.034 cfs + 13 cfs) - 13 cfs x 

4.8 pg/l] / 0.034 cfs 

= 4,720 pg/l 

WLAa = [25.7 ug/l x (0.034 cfs + 10.1 cfs) - 10.1 cfs x 

4.8 pg/l] IO.034 cfs 

= 6,234 pg/l. 

The human health WIA for nickel was calculated at the harmonic 

mean flow: 

w,m/,h = [13.4 pg/l x (0.034 cfs + 38 cfs) - 38 cfs x 

13.2 ug/l / 0.034 cfs 

= 237 ug/l. 

7.2.5 Dsrelbp PennIl Udfs 

Permit limits were developed using a steady-state, two-value WL4 

model as described in Box 5-2, Chapter 5. Values for constants 

were obtained from Table 5-2, Chapter 5. 

Step 1: Calculate LTA (note: this is Step 2 in Box 5-2) 

The chronic long-term average (LTA) for copper was calculated 

using the following formula: 

LTh = WLA x exp [OS o 2 - z o] 

= 4,720 ug/l x 0.440 

= 2,077 pg/l 

where values of exp [ 0.5 o2 - z ou ] are presented in Table S-1 

(see Chapter 5). The CV of 0.8 was used, and following the 

132 
guidance of Section 5.5.4, the z value for the 99th occurrence With a CV of 0.6, four samples per month for sampling, and a 

probability was used. 99th percentile used for the MDL, the factor is 1.64: 

The acute LTA for copper was calculated, again using the 99th 

percentile occurrence probability values from Table 5-1 as the 

multiplier: 

MDL = AMLx1.64 

= 237 Pg/l x 1.64 

= 389 Pg/l. 

LTAa = 6,234 Pg/l x 0.249 

= 1,552 Pg/l. 

lines 

The LTA for nickel human health permitting is considered to be 

the same as the WLA because the 70-year averaging period is 

used for human health evaluations (see Section 5.4.4). The LTA is 

calculated as: 

LTAf, = WL$, 

= 237 Pgg/l. 

The NPDES regulations require that effluent limits require treatment characteristic of the appropriate treatment technology and 

also achieve water quality standards. If water quality-based limits 

are more stringent than BAT limits, then the water quality-based 

limits become the basis for the effluent limits. Conversely, if the 

treatment technology (BAT) limits are more stringent, then they 

become the basis of the limits. 

Step 2: Determine the More Limiting LTA 

The limiting LTA for each pollutant was the minimum of the 

chronic, acute and human health LTA. The limiting LTA value was 

used in the next step to calculate maximum daily limits and 

average monthly limits. The limiting LTA for copper was found to 

be the acute LTA (1,552 kg/l) and the limiting LTA for nickel was 

found to be the human health LTA (237 ug/l). 

The comparison between the water quality-based and technology-based effluent limits are shown below. The more stringent 

limits are different for different pollutants: for nickel, water quality-based limits are more stringent whereas for copper, the BAT 

limits are the more stringent. 

Coowr Nickel 

Step 3: Calculate Maximum Daily and Average Monthly Limits 

The maximum daily limit (MDL) for copper was calculated using 

the expression: 

MDL = LTA x exp [z o - 0.5 a21 

= 1,552 ug/l x 4.01 

= 6,224 ug/l 

Water quality MDL 6,224 389 

AML 2,716 237 

BAT MDL 3,380 3,980 

AML 2,070 2,380 

Limit to use MDL 3,380 389 

AMC 2,070 237 

where the appropriate value for exp [ z o - 0.5 02] was taken from 

Tabfe S-2 using the row with the CV for copper (0.8) and the 

column for the 99th percentile probability basis. 

In accordance with NPDES regulations, the effluent limits were 

expressed in the permit as mass (pounds per day) by multiplying 

the concentrations above by the effluent flow of 0.034 cfs and the 

conversion factor of 5.394: 

The average monthly limit (AML) for copper was calculated using 

the expression: 

AML = LTA x exp [ z on - 0.50,-,~] 

= 1,552 fig/l x 1.75 

= 2,716 ug/l 

MDL 

AML 

Copper 

(lb/d) 

0.62 

0.38 

Nickel 

(lb/d) 

0.071 

0.043 

where the value for exp [ z CT,, - 0.5 o,~] was taken from Table 5- 

2 and, for this case, the number of samples per month was four. 

following the recommendations in Section 5.5.4, the z value for 

the 95th percentile probability basis was used. 

The effluent limits for nickel were determined by using the recommendations in Section 5.4.4, Chapter 5. The AML was considered 

to be identical to the W&, whereas the MDL was calculated from 

the AML by using the appropriate multiplier factor in Table 5-3. 

7.2.7 Cm#ariingD~lindtDsveloprnenttet~ds 

Permit limits for copper also were developed using a Monte Carlo 

simulation in order to compare the results to the permit limits 

derived from the two-value, steady-state model. A Monte Carlo 

simulation was used to generate receiving water concentrations 

to determine the effluent LTA for each of the pollutants such that 

the water criteria are achieved at the required frequency in the 

water quality standards. 

133 
Monte Carlo simulation used the same completely mixed dilution 

equation as was used for the steady state calculation: 

C = (Q&e + QsWQ + 9s) 

where C is the receiving water concentration (in Pg/l); C, and C, 

are the effluent concentration and the background concentration 

of the receiving water, respectively (in Pg/l); and Qe and Qs and 

effluent and receiving water flows, respectively (in cfs). Effluent 

flows were held constant at the mean effluent flow, and river 

flows were read from a computer file containing 60 years of daily 

flow data provided by the U.S. Geological Survey. The effluent 

concentrations were characterized by a lognormally distributed 

random variate. The random variate had a coefficient of variation 

that matched the CV of the pollutant in the effluent. 

The Monte Carlo simulation was run using 22,276 iterations. 

Once 22,276 receiving water concentrations had been calculated, receiving water concentrations were sorted, highest first. 

The 20th value (corresponding to the maximum concentration 

expected for 1 day in 3 years) was compared with the appropriate 

criterion. The 1 -day in 3-year return frequency is recommended 

by EPA for criteria (see Chapter 2). lf this value was higher than 

the criterion, the effluent LTA was reduced, and a new set of 

22,276 numbers was generated. When the receiving water concentration of the 20th value was just under the water quality 

criterion (and the 19th value was just over the same value), then 

the LTA effluent concentration generating these results was sufficient to achieve the water quality criterion; this LTA was then used 

in permit limit determinations. 

For chronic criteria, 4-day average concentrations were generated 

by taking the 4-day running average of modeled daily concentrations. The recurrence concentration was calculated in the same 

way as the l-day calculations described in the previous paragraph. Calculations were not made for the human health criterion. 

The permit limits were calculated according to the procedures 

given in Box S-3. Each LTA was multiplied by the 99th percentile 

multiplier from Table 5-3 for the MDL, and by the 95th percentile 

multiplier from Table 5-3 for the AML. For the AML, the same 

number of samples were used for the steady state and Monte 

Carlo permit limits (n=4). Thus, the resulting permit limits are 

directly comparable. The results of the Monte Carlo simulation for 

copper compared to the steady state calculations in units of 

micrograms/liter are shown below: 

Monte Carlo 

Steady State 

Maximum Average 

Daily Monthly 

8,618 3,761 

6,224 2,716 

7.3 CASE2 POTWDISCIIASE 

The second example is 01’ 3 fictitious POlVV that discharges to the 

same reach as the Jaybird C’orporation. The NPDES permit for this 

facility also is up for reissuance. The example highlights the use of 

background receiving water concentrations, and demonstrates 

the differences between industrial and POTW permit limits. In 

developing permit limits for the POlW in this example, the 

potential impacts from the Jaybird Corporation discharge were 

considered in the use of background receiving water concentrations. The interrelationships between the two facilities are discussed explicitly in Section 7.4. 

7.3.1 6l?nmai slle Ddscripuon %mi IThe Locapunct River receives discharges from a POlW serving the 

city of Auburn, a small city of about 10,000 people. The POlW 

treats a mixture of household and industrial waste with an activated sludge process. The mean effluent flow from the POTW is 

1.23 cfs. The POTW has no pretreatment program, but the 

municipality generally is aware of the small industries that are 

indirect dischargers because of research conducted by a local 

university. Generally, the plant is well operated. 

7.3.2 Em& C~c~~oll for !qt?cmc clbidmk 

The permitting authority’s approach for determining which pollutants cause, have the reasonable potential to cause, or contribute to excursions above water quality standards applies to POTWs 

as well as industries. The authority used the procedures described 

for the jaybird Corporation in the evaluation of the Auburn POTW. 

Step 1: Identify Pollutants of Concern 

At the time of the last permit issuance, there was evidence of a 

number of toxic pollutants in the POTW’s effluent, including 

copper, chlorine, and ammonia. These pollutants had monitoring requirements in the previous permit. Because there were 

metals in the effluent and, due to the industries discharging into 

the POTW sewer system, the permitting authority requested the 

POTW to conduct a complete priority pollutant scan of the effluent. The data received following the Section 308 letter request 

indicated that the concentrations of all priority pollutants except 

copper were below detection limits. The POTW’s primary toxic 

pollutants of concern were copper, chlorine, and ammonia (see 

Table 7-2). 

Step 2: Determine RAC, CMC, or CCC for Pollutants of Concern 

As described in the example of the industrial discharge, the water 

quality standards include numeric criteria for copper. The State 

also has adopted a numeric criterion for ammonia that is a 

function of the river 85th percentile pl-l and temperature; these 

values are 8.25”C and 25’C, respectively. Finally, the State interprets its narrative criterion of “no toxics in toxic amounts” to 

require use of the federal water quality criteria in the absence of a 

numeric state criterion. As a result, the permitting authority uses 

the federal criteria for chlorine. The applicable water quality 

criteria for the river are as follows: 

Copper 

Chlorine 

Ammonia 

ccc 

W/l) 

17.1 

11 

540 

CMC 

@3/l) 

25.7 

19 

4,000 

134 
Table 7-2. Effluent Data for the Auburn POlW 

n 

1 268 185 11,009 

2 115 301 13,025 

3 228 881 12,201 

4 59 372 24,548 

5 53 245 9,700 

6 213 244 15,645 

7 68 123 21,358 

8 200 343 3,976 

9 262 153 22,307 

10 519 448 7,427 

11 53 1,022 11,834 

12 474 347 8,430 

13 115 130 4,382 

14 2.59 128 9,330 

15 404 271 6,137 

16 57 451 6,448 

17 101 701 37,772 

18 187 582 14,307 

19 103 178 16,848 

20 76 436 28,205 

21 198 347 12,119 

22 265 475 11,778 

23 60 153 3,109 

24 112 268 4,474 

Mean 185 366 13,182 

SD 133 235 8,491 

cv 0.7 0.6 0.6 

Max 519 1,022 37,772 

Min 52.6 123 3,109 

Copper 

INI 

Chlorine Ammonia Toxicity 

l-u‘ 

1.5 

0.6 

0.4 

2 

1 

Source: DMR data for chemicals; 308 request for whole effluent toxicity. 

Notes: 

Metals as total recoverable; toxicity in toxic units (1001NOEC). 

The results are the highest toxic units for any of the test organisms used. 

Step 3: Determine Dilution for Aquatic Life and Human Health 

Impacts 

The State water quality standards requires that compliance with 

water quality criteria be achieved at the edge of the mixing zone. 

The standards specify the minimum dilution at which the criteria 

apply. These are the 7410 flow for the CCC, the 1 Ql 0 flow for 

the CMC, and the harmonic mean flow for human health criteria 

(RAC). The U.S. Geological Survey operates a gaging station on 

the river. The Row statistics were calculated using the data from 

this station: 

l Harmonic mean flow = 38.0 cfs 

l 7410 flow = 13.0 cfs 

l 1Q10flow=10.1 cfs. 

The POTW is located at a bend of the river where mixing is rapid. 

Therefore, the permitting authority used the complete mixing 

equation to calculate the receiving water concentrations. This is 

the same equation used for the industrial example. 

Step 4: Determine Reasonable Potential for Excursions 

The determination of possible exceedances in the CMC or CCC 

was based on a calculation of the maximum receiving water concentration of each pollutant, followed by a comparison to the 

appropriate receiving water criterion. The calculation of the maximum receiving water concentrations were made using the statistical estimate of the 99th percentile concentration of each pollutant 

in the effluent, the same flow used in the industrial example, and 

considered background receiving water concentrations of: 

Copper 4.8 pg/l 

Chlorine 0 w/l 

Ammonia 120 fig/l. 

The maximum effluent concentration was estimated using the 

statistical approach in Chapter 3. There were 24 concentrations 

of each chemical reported in the DMRs. For copper, these 

concentrations had a maximum value of 519 Pg/l, an arithmetic 

mean of 185 pg/l, an arithmetic standard deviation of 133, and 

an arithmetic coefficient of variation of 133/l 85, or 0.7. The 

multiplier was calculated to be 2.4 based on the CV of 0.7, 24 

observations, and a 99percent confidence level (see Section 3.3.2). 

Similar calculations were conducted for chlorine (multiplier of 

2.2) and ammonia (multiplier of 2.2). 

The receiving water concentrations for each pollutant were calculated. An example calculation for the comparison of copper to 

the CCC is shown below: 

C = J(2.4 x 519 us/l x 1.23 cfs) + (4.8 us/l x 13 cfs)l 

(1.23 cfs + 13 cfs) 

= 112pg/l 

where 

519 pg/l = the maximum measured effluent concentration 

2.4 = the statistical multiplier 

1.23 cfs = the average effluent flow 

4.8 Pg/l = the upstream receiving water concentration 

13cfs = the 7410 flow. 

The maximum receiving water concentrations for comparison to 

applicable standards for all pollutants were calculated to be: 

Copper 

ccc 

CMC 

Chlorine 

ccc 

CMC 

Ammonia 

ccc 

CMC 

Criterion 

w-II0 

17.1 

25.7 

11 

19 

540 

4,000 

Receiving Water 

Concentration 

@g/l) 

112 

140 

194 

244 

7,292 

9,128 

135 
--- 

The effluent characterization showed the reasonable potential for 

excursions above the CCC and CMC for copper, chlorine, and 

ammonia. Therefore, permit limits were developed for these 

pollutants. 

7.3.3 Eiflumt B fw ml@ Ef&rsnt foxicit~’ 

Step 1: Dilution Determination 

The initial dilution determination was used to establish the types 

of toxicity tests that must be conducted to characterize the effluent. The dilution at the low flow characteristics for the facility is 

the following: 

At the 7410, dilution = (1.23 cfs + 13 cfs)/l.23 cfs 

= 11.6 

At the lQ10, dilution = (1.23 cfs + 10.1 cfs)/l.23 cfs 

= 9.2. 

Step 2: Conduct Toxicity Testing 

EPA recommends that a discharger having a dilution less than 100 

be required to conduct chronic testing. The permitting authority 

requested through a Section 308 letter that the POTW provide 

quarterly chronic toxicity data for the year prior to permit 

reissuance. Tests using Selenastrum, Ceriodaphnio, and Pimephaies 

were required. The permitting authority also required the permittee to report the test results at the 48-hour endpoint so that acute 

toxicity also could be measured. Table 7-2 summarizes the results 

of the whole effluent toxicity testing. 

Step 3: Determine Reasonable Potential for Excursions 

As explained in the industrial example, the State interprets its 

narrative criteria for whole effluent toxicity to require that the 

technical support document recommendations of 0.3 TU, and 1 .O 

Tu, be used as numeric values for acute and chronic toxicity, 

respectively. In accordance with the State standards, the CMC 

applies under the lQ10 flow and the CCC applies under the 

7410 flow. 

The reasonable potential determination of exceedance of the 

CMC or the CCC was conducted in the same way as described in 

the industrial example. Upstream ambient water was used as a 

diluent to assess contributions directly from background toxicity; 

therefore, the upstream receiving water concentration was set to 

zero. The maximum effluent concentration was again estimated 

by using the statistical approach in Chapter 3. For the same 

reasons as were expressed in the industrial example, a multiplier 

of 4.7 was used. 

The receiving water concentration for chronic toxicity for comparison with the CCC was calculated using data from Table 7-2: 

C = (4.7 x 2 TU, x 1.23 cfs) + (0 TU, x 13 cfs) 

(1.23&+ 13cfs) 

= 0.8TUc 

where 

13 cfs = the receiving water flow at 7410 

1.23 cfs = the mean effluent flow 

4.7 = the statistical effluent multiplier 

4 TU, = the maximum effluent concentration. 

The value of the calculated receiving water concentration, 0.8 

TU,, is less than the chronic water quality standard of 1 .O TU,, and 

therefore there is no reasonable potential for the CCC to be 

exceeded. 

To calculate the receiving water concentration for acute toxicity, 

the permitting authority first converted the chronic toxicity data 

into equivalent acute toxicity units by applying the ACR of 2 

obtained from the monitoring data. The receiving water concentration for acute toxicity was then calculated: 

C= [(4.7x2TUc/2ACRx1.23cfs)+(OTU,x10.1 cfs)] 

(1.23 cfs + 10.1 cfs) 

= 0.5 TU, 

where 10.1 cfs is the receiving water flow at 1 Ql 0, 2 is the acute 

to chronic ratio, and the other values are the same as above. The 

calculated value of 0.5 TU, is greater than the criterion of 0.3 TU,, 

Therefore, there is reasonable potential for the CMC to be exceeded and permit limits were developed for whole effluent 

toxicity. 

7.3.4 lhthmnim wasteload All&iWLAs for chemicals and whole effluent toxicity were determined 

using information on the available dilution at the edge of the 

mixing zone. The calculation of WIA using the steady-state model 

was described in Section 7.2.4. The WLAs for the POTW using the 

equation discussed in Section 7.2.4 are: 

wLAa 

WLA, 

Toxicity Copper Chlorine Ammonia 

t-w WI) WD (WI/l) 

2.8 197 175 35,860 

11.6 147 127 4,979 

7.3.5 ik7nT&pPlwnlltlhMs 

The permit limit development process described in Box 5-2, 

Chapter 5 was applied to all pollutants. This process is identical to 

that explained in Section 7.2.5 except that (1) the WLA for acute 

toxicity needs to be expressed in equivalent chronic toxic units by 

multiplying by the ACR of 2, and (2) daily sampling of chlorine is 

required in the permit. The calculated LTA and permit limits are: 

LTA, 

LW 

MDL 

AML 

Toxicity Copper Chlorine Ammonia 

TUC 019/l) &l/b &l/l) 

1.8 55.4 56.2 11,511 

6.1 70.7 66.9 2,625 

5.6 197 175 8,162 

2.8 91 87 4,067 

136 
7.3.6 llotmdning and Expssia6 Llre Gontrollin6 Effluent 

llndt 

The treatment technology for POTWs is secondary treatment and 

is characterized by effluent limits for biochemical oxygen demand, total suspended solids, and pti. There are no BAT limits for 

toxics for POlWs, so there was no need to compare these water 

quality-based limits with other limits to determine which were 

more stringent. 

The permitting authority decided to use acute toxicity tests rather 

than chronic tests to measure compliance with the toxicity effluent limits. The appropriate effluent limits in terms of TU, were 

calculated by dividing the above calculation for TU, by the ACR of 

2 that was obtained from effluent monitoring. 

In accordance with NPDES regulations, the effluent limits for 

chemicals were expressed in the permit as mass (pounds per day) 

by multiplying the concentrations above by the effluent flow of 

1.23 cfs and the conversion factor of 5.394. Because there is no 

equivalent mass based unit for toxicity, toxicity mass limits are 

impractical under the regulation. 

MDL 

AML 

Toxicity Copper Chlorine Ammonia 

TUa (lb/d) (I b/d) (lb/d) 

2.8 1.31 1 .16 54.2 

1.4 0.64 0.58 27.0 

7.3.7 ~/ng DhYwent limit &?vetopnn?nt Moth& 

Permit limits also were developed using a Monte Carlo simulation 

to compare the results to the steady-state permit limits. A Monte 

Carlo simulation was used to generate receiving water concentrations for determining the appropriate LTA for each of the pollutants. The methodology for the Monte Carlo simulation is presented 

in Section 7.2.7. The results for this case are presented below. 

MOLs in TU, and ug/l 

Toxicity Copper Chlorine Ammonia 

Monte Carlo 3.9 264 249 9,657 

Steady State 2.8 197 175 8,162 

AMLs in TU, and pg/l 

Toxicity Copper Chlorine Ammonia 

Monte Carlo 2.7 171 170 6,614 

Steady State 1.4 91 87 4,067 

7.4 CASE 3: MDLTlPlE DlSCHARDES INTO THE SAME 

REACH 

Permit development for water quality-based toxics control has 

been illustrated for two single dischargers. This process increases 

in complexity in cases of multiple dischargers into a reach. The 

development of permit limits for multiple dischargers is based on 

the degradation in water quality resulting from the combined 

discharges, the development of total maximum daily loads (TMDls) 

for the river reach before generating WI& and the allocation of 

discharges to each discharger. The following example describes 

the permit development process when two dischargers release 

effluent into the same reach of a river. The dischargers are the 

Jaybird manufacturing plant described in Case 1 and the Auburn 

POTW described in Case 2. These facilities discharge into the 

Locapunct River, whose flow characteristics previously were described. 

7.4.1 Effluent Chamcterbafion 

The major differences in the effluent characterization for one 

facility and for multiple facilities is to identify those pollutants that 

are common to more than one facility, and to determine whether 

the combined discharges cause or are likely to cause water quality 

standards excursions. 

Step 1: Identify Pollutants of Concern 

Based on the data in Form 2C, the DMRs from the laybird 

Corporation and the data in the DMRs and Section 308 request 

from the Auburn POTW, the permitting authority found two 

contaminants common to both discharges: copper and whole 

effluent toxicity. Lead and nickel were found to be a problem at 

the Jaybird Corporation, but since there were no complicating 

discharges from the POTW, it was dealt with as a pollutant only at 

the metal finishing facility. Similarly, chlorine and ammonia were 

discharged solely by the POTW, so it was not necessary to provide 

effluent limits for the metal finishing facility for these chemicals. 

Step 2: Determine the CMC and CCC for Pollutants of Concern 

The numerical standards adopted by the State already have been 

presented. The relevant values for copper and whole effluent 

toxicity are: 

Copper 

Toxicity 

ccc CMC 

17.1 f.lg/l 25.7 ug/l 

1 .O TU, 0.3 Tu, 

Step 3: Determine Dilution for Aquatic Lie and Human Health 

Impacts 

Since this example is concerned with potential excursions above 

standards resulting from the collective discharge of two dischargers, the calculation of dilution includes the combined effluent flow 

from both facilities. The combined dilution can be characterized 

by the complete mixing equation: 

C = (&I Qel + C,zQez + CsQsMQet + Qe2 + Qs) 

where 

Qel and Qez = the flows of the two facilities 

C,l and Cc2 = the effluent concentrations of the two facilities 

CS = the upstream receiving water concentration 

Qs = the receiving water flow. 

137 
Step 4: Determine Reasonable Potential for Excursions 

To determine if the CMC or CCC were exceeded as a result of the 

combined discharges into the river, the receiving water concentration of each pollutant was calculated and compared to the 

appropriate criterion. The receiving water concentration calculation was based on the maximum value of the effluent concentralions (obtained from effluent data and multiplied by the appropriate statistical factor), average effluent flows, background receiving 

water concentrations, and appropriate river flows. All this information has been presented previously in the separate examples. 

The following results were obtained: 

Copper 

ccc 

CMC 

Toxicity 

ccc 

CMC 

Criterion 

01gA) 

17.1 

25.7 

1.0 

0.3 

Receiving Water 

Concentration 

@s/l) 

156 

194 

0.57 

0.45 

These calculations demonstrated exceedances of the copper CCC 

and CMC criteria and the toxicity CMC criterion. Permit limits 

were required. 

7.4.2 TIII#LsstnlHZ& 

WLAs were calculated to develop permit limits. WLAs for each 

discharger and chemical were based on calculated TMDLs, the 

total load to the Locapunct River that would not result in water 

quality standards exceedances. TMDLs are comprised of a load 

allocation for nonpoint sources, WlAs for point sources, and, if 

required by the State, a reserve capacity. TMDLs are further 

described in Section 4.2, Chapter 4. 

Step 1: Calculate TMDL 

The first step in developing individual WlAs for the two dischargers was to develop TMDLs for each pollutant of concern. TMDLs 

were developed in the same way as an individual WLA with the 

total load of a pollutant from the two dischargers being considered as a single discharge. 

The calculation of TMDLs used the following formula: 

TMDL=WQSx(Qt+Q,) 

where 

WQS = the water quality standard 

Qt = the combined flow of both effluents 

QS = the appropriate receiving water flow. 

The acute copper TMDL was calculated by using the data presented in the previous hyo examples as: 

TMDL = 25.7 lg/l x (0.034 cfs + 1.23 cfs + 10.1 cfs) 

= 292 pg-&/I 

where 

25.7 pg/l = theCMC 

0.034 cfs and 

1.23 cfs = the average effluent flows 

10.1 = the 1QlO. 

Similar calculations were made for chronic copper and acute 

toxicity. A TMDL was not calculated for chronic toxicity because 

the information presented in Chapter 1 indicates that chronic 

toxicity does not demonstrate additivity. The results are summarized below. 

Copper bg-cfs/l) 

Toxicity (TU,-&/I) 

Total Maximum Daily Loads 

Chronic Acute 

244 292 

NA 3.4 

Step 2: Develop WlAs 

The State had adopted an approach into the water quality management plan that described how WLAS were to be calculated. 

The approach required that existing upstream concentrations be 

used to determine the load allocation part of the TMDL and that 

10 percent of the TMDL had to be reserved and unavailable for 

allocation. The remainder of the TMDL could be apportioned to 

point sources in the WLA. 

The permitting authority decided to allocate the wasteloads based 

on the proportion of the existing load of each parameter that was 

attributed to each of the existing discharges. Based on the 

information shown in Tables 7-l and 7-2 and the average effluent 

flows, the pollutant loads from each facility are shown below. 

Parameter 

COP per 

@g-ds/l) 

Toxicity 

0%6s) 

Auburn POTW Jaybird Corporation 

Load Proportion Load Proportion 

227.6 0.77 66.1 0.23 

1.23 0.90 0.14 0.10 

Individual WLAs were then determined using the following 

equation: 

WfA = (TMDL - LA - 10% TMDL) x proportion/Q 

where the chronic TMDL was used to determine the chronic WLA, 

and the acute TMDL was used to determine the acute WLA for 

each facility. The WLAs for each pollutant and for each facility are 

presented on the following page. 

138 
Jaybird 

Copper 6.0) 

Toxicity UU,) 

Acute WLA 

134 1,450 

2.2 9.0 

Chronic WLA 

98.4 1,063 

NA NA 

7.4.3 PfmIdtumnlhvf~ 

Once the WLAs had been determined, permit limit development 

proceeded as in the previous examples. LTAs were calculated 

from the WLAS, and the limiting LTA was selected for calculating 

permit limits. For the metal finisher, where BAT limits were more 

restrictive than the water quality-based limits, the BAT limits 

applied. For the POTW, permit limits for toxic materials were 

required only to prevent exceedances of water quality standards. 

This process is summarized below. 

Step 1: Calculate LTAs 

The LTA was calculated for each discharger and pollutant as 

described in Step 2, Box 5-2, Chapter 5; the LTAs are shown 

below. 

Parameter 

Copper (c1gN 

Toxicity (TU,) 

Acute LTA 

POIW Jaybird 

37.7 361 

0.71 2.9 

Chronic LTA 

POW Jaybird 

47.3 468 

NA NA 

Step 2: Determine the More Lmiting LTA 

The minimum LTA was used to calculate MDLs and AMLs. The 

acute LTA was the lower LTA for both pollutants. 

Step 3: Calculate the Maximum Daily and Average Monthly 

Limits 

The MDL and AML were calculated as described in Box 5-2, 

Chapter 5: 

Average Monthly Limit Maximum Daily Limit 

Parameter POTW Jaybird POTW jaybird 

Copper @g/l) 62 632 134 1,448 

Toxicity (TU,) 1.1 4.5 2.2 9.0 

Step 4: Express the Limits 

The final step is to compare the water quality-based limits to the 

BAT limits to ensure that the more restrictive of the two are used, 

and to express the copper limits in terms of mass. The copper 

water quality-based limits for Jaybird Corporation are lower than 

the BAT ones (see Section 7.2.6). Therefore, the water qualitybased limits are required by the permit. In addition, the limits are 

lower than those calculated when only one of the facilities were 

considered. The final permit limits are listed below. 

Average Monthly Limit Maximum Daily Limit 

Parameter POlw Jaybird Polw Jaybird 

Copper (lb/d) 0.41 0.12 0.89 0.27 

Toxicity (TU,) 1 .l 4.5 2.2 9.0 

139 
Acute toxicity endpoints (ATEs) 

lethal concentration (LC) 4 

Acute toxicity testing 59 

Acute-chronic ratio (ACR) 17 

Additivity 24 

Allowable Effluent Concentration Distribution 82 

Ambient toxicity testing 61 

Ambient-induced mixing 77 

lateral dispersion coefficient 77 

shear velocity 77 

Amelia River 68 

Ames test 25 

Analytical considerations for chemicals 65 

Antidegradation policy 29 

Aquatic community 18 

Aquatic Lie Protection 34 

ARM 84 

BAF 38 

Bioaccumulation 37, 38, 72 

Bioaccumulation consideration 38 

Bioconcentration 38, 64 

Biocriteria 41,42 

Biological assessment/bioassessment 18, 20 

Biological criteria 

biological integrity 1, 18 

Biological surveylbiosurvey 18, 19 

Calculations 

CCC for toxicity 85 

CMC for toxicity 85 

Concentration (multiple dischargers) 86 

Concentration (nonconservative pollutant) 87 

Harmonic mean flow 88 

Lateral dispersion coefficient 77 

Carcinogenic&y 25 

Carcinogens 68 

Carcinogens, calculating l?ACs 40 

CCC 34,85 

CCC. See Criterion continuous concentration 79, 85 

Center for Exposure Assessment Modeling (CEAM) 73 

Chronic toxicity endpoints 

effective concentration 4 

lowest observed effect concentration 4 

no observed effect concentration 4 

Chronic toxicity testing 59 

Clean Water Act (CWA) 1, 67 

CMC 34, 71, 85 

CMC. 71 

Coefficient of variation (CV) 95 

in permit limit derivation 105 

Completely mixed discharge-receiving water situations 

Complex Effluent Toxicity Testing Program (CElTP) 7, 9 

Compliance monitoring 123 

discharge monitoring report/quality assurance 124 

inspections 124 

self-monitoring report 123 

Compliance problems 53 

Concentration 

flow distance 77 

Continuous Simulation 80 

CORMIXl 76 

Criterion continuous concentration (CCC) 48 

Criterion maximum concentration (CMC) 48, 71, 85 

Critical conditions 67 

Critical design periods 

estuaries and coastal bays 74 

oceans 74 

rivers and run-of-river reservoirs 73 

lakes, reservoirs 73 

Design periods. See Critical design periods 

Designated use 54 

Detection level 

minimum level 111 

practical quantitation limit 112 

Detection levels 111 

Determining the need for a limit 

statistical approach 56 

when is a chemical-specific limit sufficient? 62 

with effluent data 55 

without effluent data 50 

Dilution 52-53, 61 

Dilution determination 58, 63 

Discharge monitoring reports 54 

Discharge-Induced Mixing 75 

Duration 31-32 

Duration for single chemicals and WET 35 

Dye study 51, 58 

Dynamic modeling. See Modeling 

Modeling techniques; Models 76, 78, 79 

DYNHYD4 89 

DYNTOX 83,84 

Effluent bioconcentration evaluation 42, 64-65 

Effluent characterization 47 

addressing uncertainty in 56 

for aquatic life effects 48 

for human health effects 48, 62 

or multiple dischargers 60-61 

for specific chemicals 61-63 

for whole effluent toxicity 56-60 

process 53, 63 

78 

141 
Effluent characterization (cont.) 

purpose 48 

special considerations for marine and estuarine 

systems 61 

Effluent variability 

basic principles 93 

Enforcement 125 

enforcement discretion 125 

enforcement mechanisms 125 

whole effluent toxicity enforcement 124, 125 

EXAMS-II 84 

Excursion above CMC or CCC 60 

Excursions above ambient criteria 50 

Expressing limitations and developing monitoring require 

ments 110 

Expressing permit limits 

mass-based limit 110 

maximum daily 96 

FCM2 85 

FCETS 85 

Fish consumption values 37 

Fishable/swimmable 29 

FLOSTAT 89 

Food chain 87 

Frequency 31, 32 

Frequency for single chemicals and WET 36 

CC/MS 64 

Generating Effluent Data 56 

Cenotoxic pollutants 25 

Health effects 25 

nonthreshold effects 25 

threshold effects 25 

HPLC 65 

HSPF 84 

Human exposure 

Background concentrations 37 

drinking water ingestion 37 

fish consumption 37 

Human health criteria 

Ql l 39,40 

RfD 39, 40 

updating 38 

Human health protection 25 

Human health protection (WQC) 36 

Human health/Human exposure 37 

Implementation methods for state antidegradation policies 

Tier I 29 

Tier II 30 

Tier Ill (ONRWs) 30 

Independent application 22, 31, 49 

Integrated approach 1 

bioassessment approach 1, 22 

chemical-specific approach 1, 20 

whole effluent approach 1,4, 21 

Integrated Risk Information System (IRIS) 38 

Isopleths, concentration 72 

LA. See Load allocation 67 

Lateral dispersion coefficient 77 

LC50 4, 57, 58, 71 

Limits for metals 111 

Load allocation 67 

Lognormal Probabilistic Dilution Model 82 

Long term average (LTA) 95 

Magnitude 3 1, 32 

Magnitude for single chemicals 34 

Magnitude for whole-effluent toxicity 35 

Magnitude, duration, and frequency (Criteria) 31, 32 

Margin of safety 67 

Marine and estuarine discharges 61 

Marine and estuarine permitting 104 

Maximum daily permit limits 

chronic toxicity 96 

Metals 111 

MINTEQA2 84,85 

Mixing zone 58, 72 

Mixing Zones 33 

Modeling techniques 

continuous simulation 81 

lognormal probabilistic dilution model 82 

Monte Carlo simulation 81 

steady state 78 

Models 

CORMIXl 76 

DYNHYD4 84 

DYNTOX 84 

EXAMS-II 84 

FCM2 85 

FCETS 85 

FLOSTAT 89 

HSPF 84 

MINTEQA2 85 

Mixing zone 70 

PSY 78 

SARAH2 85 

Selection of 83 

STORET 79 

TOX14 84 

UDKHDEN 77 

ULINE 77 

UMERGE 77 

UOUTPLM 77 

UPLUME 76, 77 

WASP4 84 

142 
Monte Carlo simulation 80, 81 

Monticello Ecological Research Station (MERS) 2 

Multiple source toxicity testing procedures 60-61 

Multiple-source discharge 60-61 

Narrative criteria 29 

Noncarcinogens 89 

NPDES program 1 

Number of samples 

in permit limit derivation 105 

Numeric criteria 29 

Outfall design recommendations 

in lakes and reservoirs 73 

in oceans 74 

in rivers 73 

multiport submerged 73 

single-port submerged 73 

surface discharge 73 

Outstanding national resource waters (ONRWs) 30 

Penalties 124 

Permit documentation 110 

Permit limit derivation 98 

aquatic life protection 98 

average monthly 96 

average weekly 96 

basic objective 96 

detection levels 111 

direct application of both the acute and 

chronic WlAs 104 

dynamic 101 

human health protection 104-l 05 

maximum daily 96 

other approaches 103 

selection of monitoring frequencies 113 

single value steady state 102 

two value steady state 98 

use of a WLA as a permit limit 96-97 

Pollution prevention 111 

Potential for excursion above CMC or CCC 58 

POlw 53 

Precision 2, 11, 12 

coefficient of variation (CV) 12 

inter-laboratory precision 2, 11 

intra-laboratory precision 11 

variability 11 

Priority toxic pollutants 30 

Probability basis 

average monthly 110 

daily maximum 110 

in permit limit derivation 110 

LTAforWlA 110 

Quality assurance 12, 123 

discharge monitoring report/quality assurance 124 

Reasonable potential 48,49,50, 58 

as a trigger 58 

for multiple dischargers 60 

for whole effluent toxicity 58 

regulatory basis 49 

with effluent data 50, 56 

without effluent data 49 

Receiving water concentration (RWC) 48 

Reference ambient concentration (RAC) 48 

Reference toxicants 12 

Regulation requirements 4849 

Reporting violations 126 

to the public 126 

to the regulatory agency 124 

Return period 82 

Rhodamine WT. See Tracer (dye) studies 75 

SARAH2 85 

Screening protocol 53 

Sediment 42,67 

Sediment criteria 42 

Shayler Run, Ohio 2 

Single value wasteload allocations 

use in permit limit derivation 102 

Species sensitivity 59 

Species sensitivity differences 16 

Statistical considerations of effluent limits 105 

changes in CV on limits 106 

changes in CV on LTA 105 

changes in monthly samples 105, 107 

changes in probability basis on limits 105, 110 

Statistical considerations of WLAS 96 

Statistical distributions of effluent data 

lognormal (positively skewed) 95 

normal (bell shaped) 95 

STORET 79 

TMDL. See Total maximum daily load 

Total maximum daily load 

calculation of 78 

margin of safety 67 

Total maximum daily load (TMDL) 1, 67, 78 

TOXl4 84 

Toxic units (TVs) 6 

acute toxicity units (TU,) 7 

chronic toxicity units (TV,) 7 

Toxicity 

acute toxicity 4 

CCC for 85 

chronic toxicity 4 

CMC for 85 

whole effluent toxicity 4, 71 

143 
Toxicity persistence 23 

Toxicity reduction evaluations 

308 letters 118-l 19 

additional testing 117-l 18 

administrative orders 114 

approach 114 

circumstances warranting a TRE 117 

consent decrees 114 

evaluation criteria 115 

guidance documents 114 

requiring TREs 118 

toxicity identification evaluation (TIE) 116 

TRE plans 115 

Toxicity test endpoint concentrations 

acute toxicity endpoints (ATEs) 4 

chronic toxicity endpoints (CTEs) 4 

Toxicity testing 11 

composite sample 13 

flow-through toxicity test 13 

grab sample 13 

off-site tests 11 

on-site tests 11 

static toxicity test 1 3 

Toxicity testing procedures 58 

Treatment plant performance 97 

Triggers for permit limit development 58, 63-64 

Tualatin River Basin 68 

UDKHDEN 77 

ULINE 77 

UMERCE 77 

UOUTPLM 77 

UPLUME 76, 77 

Variability 

effluent variability 16 

exposure variability 16 

species sensitivity differences 16 

Violation review 124 

WASP4 84 

Wasteload 67 

Wasteload allocation 

schemes 67, 69 

Wasteload allocation (WL4) 1 

Water quality criteria 1, 29, 32 

aquatic life 34 

criterion continuous concentration (CCC) 32 

criterion maximum concentration (CMC) 34, 35 

RACs for non-carcinogens 39 

reference ambient concentration (RAC) 36 

reference tissue concentration (RTCs) 37 

Water quality models 

continuous simulation 81, 98 

dynamic 98 

lognormal probabilistic 82 

Monte Carlo 81, 98 

single value steady state 97 

two value steady state 98 

Water quality standards 1 

biological criteria 1 

narrative water quafity criterion 1 

numeric criteria 1 

water quality criteria 1 

Water quality standards regulatory considerations 30 

Section 303(c)(2)(8) of CWA 30 

40 CFR 122.44 & 40 CFR Part 131 31 

Section 307(a) of CWA 30 

Section 131 .l 1 Standards Regulation 2.1 29 

When is a chemical-specific limit sufficient? 62 

Whole effluent approach 4 

Whole effluent toxicity 

“pass/fail” tests 104 

acute endpoint sensitivity 112 

chronic endpoint sensitivity 112 

description of limits 112 

detection levels 112 

end-of-pipe approach 104 

test methods 112 

use of acute versus chronic tests 112 

Whole effluent toxicity data generation 58 

WfA 67 

* This is not a comprehensive index. Only topics of importance 

are highlighted. 

144 
APPENDICES 

A. Raw Data 

B. EPA Regulations and Policies 

C. Ambient Toxicity Testing and Data Analysis 

D. Duration and Frequency 

E. Lognormal Distribution and Permit Limit Derivations 

F. Sampling 

c. The Development of A Biological Indicator Approach to Water Quality-based Human Health Toxics Control 

H. Reference Dose (RFD): Description and Use in Health Risk Assessment 

I. Chemicals Available on IRIS 

145 
APPENDIX A-1 

TOXICITY TEST PRECISION DATA 
MARINE/ESTUARINE SHORT-TERM CHRONIC TOXICITY 

TESTS 
SHEEhiEAD MINNOW (Cyprinodon variegatus) 

Seven-day Larval Survival and Growth Test 

Single Laboratory Precision Data 

Table A-l-l. Single laboratory precision of test performed in 

40 fathoms artificial seawater, using larvae from fish 

maintained and spawned in 40 fathoms artificial seawater, 

using copper as the reference toxicant [l]. 

Test 

Number ; 

, Most 1 

Go 1 

1 0.05 0.1133 

2 I <0.05* I 0.0543 

3 <0.05’ 0.0418 

4 I 0.05 0.0632 

5 

i 

<“‘05’ 0.0577 

6 I 0.05 0.0483 

7 0.05 0.0796 

8 j 0.05 j 0.1235 

n: 5 

Mean: I 0.05 

CV(o/o): NA 

1 i.0727 

41.82 

(m$l) 

0.1523 

0.0975 

0.0714 

0.0908 

0.0998 

0.1325 

0.1597 

0.2364 

Sensitive 

Endpoint 

S 

c 

G 

S 

s 

c 

G 

G 

40.77 i I 

* The lowest concentration tested was 0.05 mg./l 

NOEC Range: ~0.05’ - 0.05 mg/l. 

Copper concentrations in Tests l-6 were 0.050, 0.10, 0.20, 0.40, and 0.80 mgil 

and Tests 7-8 were 0.025, 0.050, 0.10, 0.20, and 0.40 mgll. 

Prepared by Florence Kessler, TAI, Cincinnati, OH, fanuary 11, 1990 (ICp 

Program, versron 1 .l b). 

Table A-l-2. Single laboratory precision of test performed in 

40 fathoms artificial seawater, using larvae from fish 

maintained and spawned in 40 fathoms artificial seawater, 

using sodium dodecyl sulfate (SDS) as the reference toxicant 

PI. 

2 ,l.O 

3 1.0 ( 2.3051 1 2.8367 ’ S 

4 0.5 1.9855 2.6237 ; G 

5 1.0 1.1901 ; 1.4267 5 

6 0.5 ---- , 1 1.1041 1.4264 1 c 

fl: 6 ! 6 I 6 I 

Mean: , 0.8 1.5456 1.9595 ’ 

CVl%): NA 31.44 I 31.82 ! 

NOEC Range: 0.5 - 1 .O mg!l (this represents a difference of one exposure 

concentration). 

SDS concentrations in Tests l-2 were 1 .O, 1.9, 3.9, 7.7, and 15.5 mg/l and in 

Tests 3-6 were 0.20, 0.50, 1.0, 1.9, and 3.9 mgif. 

Prepared by Florence Kessler, TAI, Cincinnati, OH, January 11, 1990 (ICp 

Program, version 1 .l b). 

Table A-l-3. Single laboratory precision of test performed in 

natural seawater, using larvae from fish maintained and 

spawned in natural seawater, using copper as the reference 

toxicant [ 11. 

I Most 

Test ’ Sensitive 

Number 1 Endpoint 

1 ; 125 1 320.3 j 437.5 j S - 

4 125 

5 ’ 125 

n: T 5 

Mean: I 106.2 

182.3 

I 

323.0 ’ C 

333.4 , 483.4 I 5 

228.4 343.8 ’ S 

300.4 I 396.9 , 

1 CW%k 1 NA I 33.0 : 19.2 ’ I 

* No linear interpolation estimate could be calculated from the data, since none 

of the group response means were less than 50 percent of the control response 

mean. 

NOEC Range: 31 - 125 mg/l (this represents a difference of two exposure 

concentrations). 

Prepared by Elise Torello, SAIC, Narragansett, RI, and Margarete Heber, EPA, 

Washington, DC, February 1990 (ICp Program, version 1 .l b). 

Table A-l-4. Single laboratory precision of test performed in 

natural seawater, using larvae from fish maintained and 

spawned in natural seawater, using sodium dodecyl sulfate 

(SDS) as the reference toxicant [l]. 

Test ’ INOEC 

Number 1 (mg/l) I 

1 ’ 2.5 

2 1.3 

3 

I 

/ 1.3 

4 1.3 

5 , 1.3 

n: 5 

Mean: 1.5 

CW%l: ; NA 

2s ; (:9/u 

2.9 

NC’ 

1.9 

I 2.4 1.5 

i 

I 4 2.2 

! 27.6 

j tSI, 

3.6 

NC2 

I 

2.4 

NC2 

-I 1.8 ----.- - 

3 

I 2.6 35.3 

’ Most , Sensitive 

I Endpoint f------ 

I s 

I G 

5 

I c 

5 

i---- --- 

NOEC Range: 1.3 - 2.5 mg/l (this represents a difference of one exposure 

concentration). 

‘No Linear interpolation estimate could be calculated from the data, smce none 

of the group response means were less than 75 percent of the control response 

-. 

2No linear interpolation estrmate could be calculated from the data, smce none 

of the group response means were less than 50 percent of the control response 

mean. 

Prepared by Elise Torelfo, SAIC, Narragansett RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1 .I b). 

A-l-l 
SHEEPSHEAD MINNOW (Cyprinodon variegatus) 

Seven-day Larval Survival and Growth Test 

Interlaboratory Precision Data 

Table A-1-5. Interlaboratory precision of test using an industrial effluent as 

the reference toxicant [ 11. 

Most Sensitive Endpoint 

Test 1 NOEC 

;i$ 

GO 

.~_____-~-~ .~ _ -. .- Number - - - A- -!%,--,----- -‘--P?-- 

Laboratory A I 

1 , 3.2 (S,G) / 7.4 (5) I 7.4 (G) 

2 1 3.2 (S,G) 7.6 (S) 14.3 (G) 

Laboratory B 

1 3.2 (S,G) 5.7 (C} 9.7 (C) 

2 3.2 (S,C) 5.7 (C) 8.8 (C) 

Laboratory C I 

1 1 .o (5) 4.7 (5) 7.2 (5) 

Laboratory II 

1 ’ 3.2 (S,G) 7.4 (G) 24.7 (G) 

2 ’ 1.0(G) -----.-F.-..e---1 ----- 5.2 (5) 7.2 (5) 

tl: 7 7 7 

Mean: j 2.6 5.5 11.3 

CV(%): NA 44.2 56.9 

NOEC Range: 1 .O - 3.2 percent (this represents a difference of one exposure concentration). 

Prepared by Elise Torelto, SAIC, Narragansett, RI, and Margarete Heber, EPA, and Washington, DC, 

February (Itp Program, version 1 .l b). 

SHEEPSHEAD MINNOW (Cyprinudm variagatus) 

Embryo-larval Survival and Teratogenicity Test 

Single Laboratory Precision Data 

Table A-l-6. Single laboratory precision of test performed in HW Marinemix 

artificial seawater, using embryos from fish maintained and spawned in HW 

Marinemix artificial seawater, using copper as the reference toxicant [l]. 

Test 

Number 

I 

ECIO 60 7 NOEC 

bJg/u OJgm wi/J) 

1 173 189 198 234 240 

2 l * t * 240 

3 l l t t I 240 

4 182 197 206 240 , 240 ’ 

5 171 187 197 234 240 

6 . * l * / <200 l l l c 220 

195 203 : 208 I 226 , 220 

n: 4 4 4 4 7 

Mean: 180 194 202 233 234 

CV(%): 6.1 3.8 2.8 2.5 NA 

l Data do not fit the Probit model. 

NOEC Range: 200 - 240 (this represents a difference of two exposure concentrations). 

A-l -2 
SHEEPSHEAD MINNOW (Cyprinodun variegatus) (continued) 

Embryo-larval Survival and Teratogenicity Test 

Single Laboratory Precision Data 

Table A-l-7. Single laboratory precision of test performed in HW Marinemix 

artificial seawater, using embryos from fish maintained and spawned in HW 

Marinemix artificial seawater, using sodium dodecyl sulfate (SDS) as the 

reference toxicant [l], 

Mean: 1.3 

11.7 ’ NA 

l Data do not fit the Probit model. 

NOEC Range: 2.0 - 4.0 ug/l (this represents a difference of one exposure concentration) 

INLAND SILVERSIDE (Menldia beryllfna 

Seven-day Larval Survival and Growth Test Single Laboratory Precision Data 

Table A-l-8. Single laboratory precision of the inland 

silverside (Menidio beryllina) larval survival and growth test 

performed in natural seawater, using larvae from fish 

maintained and spawned in natural seawater, using copper as 

the reference toxicant [I]. 

Test ; 

Number 

1 

2 ’ 

3 

4 

5 

NOEC 

(WU ----- 

63 

125 

63 

125 

31 

n: 5 

Mean: 81.4 

CV(%j: ’ NA 

I 

/ (ItgL;1) 

1 96.2 

207.2 

j 2189 

! - 177.5 

1 350.1 

I 43.7 

I 

I (i$i) A----- 

148.6 

NC 

493.4 

! 241.4 

+Y1 340.8 

I 50.7 

I Most 

1 Sensitive 

1 Endpoint 

I s 

I i 

! s t”- 

l No linear interpolation estimate could be calculated lrom the data, since none 

of the group response means were less than 50 percent of the control response 

mea”. 

NOEC Range: 31 - 125 ug/l (this represents a difference of two exposure 

concentrations). 

Prepared by Elise Torello. SAIC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1 .lb). 

Table A-l-9. Single laboratory precision of the inland 

silverside (Menidia beryllina) larval survival and growth test 

performed in natural seawater, using larvae from fish 

maintained and spawned in natural seawater, using sodium 

dodecyl sulfate (SDS) as the reference toxicant [l]. 

I I 

Test 1 NOEC ( ICL, i I& 

Most 

1 Sensitive 

Number ; (mg/l) ) @q/l) (mg/l) Endpoint 

NOEC Range: 1.3 mg/l 

Prepared by Eke Torello, SAIC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1.1 b). 

A-l-3 
Seven-day Survival, Growth, and Fedundlty Test Single 

Laboratory Precision Data 

Table A-1-10. Single laboratory precision of the mysid (Mysidopsis 

bahia) survival, growth and fecundity test performed in natural seawater, 

using juveniles from mysids cultured and maintained in natural 

seawater, using copper as the reference toxicant [I]. 

5 i125 I 157.7 j 200.3 1 S I 

n: 

Mean: 5 i 112.6 

CV(%): / NA 

l No linear interpolation estimate could be calculated from the data, since none of the 

group response means were less than 50 percent of the control response mean, 

NOEC Range: 63 125 ugll (this represents a difference of two exposure concentrations). 

Prepared by Eke Torello, SAIC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1 .lb). 

Table A-l-11. Single laboratory precision of the mysid (Mysidopsis 

bohia) survival, growth, and fecundity test performed in natural 

seawater, using juveniles from mysids cultured and maintained in 

natural seawater, using sodium dodecyl sulfate (SDS) as the reference 

toxicant [l). 

__--- 

‘No linear interpolation estimate could be calculated from the data, since none of the 

group response means were less than 75 percent of the control response mean. 

‘No linear interpolation estimate could be calculated from the data, since none of the 

group response means were less than SO percent of the control response mean. 

NOEC Range: ~0.3 _ 5.0 mg/l (this represents a difference of four exposure concentrations). 

Prepared by Elise Torello, SAIC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1 .l b). 

A-l-4 
SEA URCHIN (Arhcia punctrrlata) 

Fertilization Test Single Laboratory Precision Data 

Table A-1-12. Single laboratory precision of the sea urchin Table A-1-14. Single laboratory precision of the sea urchin 

(Arbucio punctuloto) fertilization test performed in natural (Arbacia punctulata) fertilization test performed in natural 

seawater, using gametes from sea urchins maintained and seawater, using gametes from sea urchins maintained and 

spawned in artificial seawater (40 Fathoms), using copper spawned in natural seawater, using copper as the reference 

as the reference toxicant [l]. toxicant [l]. 

Test ! NOEC 

CV(%): ( NA 

T 

c 

! 

1 

(!iil) 

8.92 

26.35 

11.30 

34.28 

36.67 

5 

23.51 

54.60 

UOEC Range: ~5.0 - 12.5 ug/l (this represents a difference of one exposure NOEC Range: ~6.1 _ 24.4 ug/l (this represents a difference of two exposure 

roncentration). concentrations). 

kpper concentrations in Test 1 were 2.5, 5.0, 10.0, 20.0, and 40.0 ug/l and in 

rests 2-S were 6.25, 12.5, 25.0, 50.0, and 100.0 ug/l. 

Prepared by Florence Kessler, TAI, Cincinnati, OH, lanuary 11, 1990 (ICp 

Program, version 1 .l b). 

Prepared by Elise Torello, SAIC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1 .l b). 

Table A-1-13. Single laboratory precision of the sea urchin Table A-l-15. Single laboratory precision of the sea urchin 

(Arbacio punctulota) fertilization test performed in natural (Arbocio punctulato) fertilization test performed in natural 

seawater, using gametes from sea urchins maintained and seawater, using gametes from sea urchins maintained and 

spawned in artificial seawater (40 Fathoms), using sodium spawned in natural seawater, using sodium dodecyl sulfate 

dodecyl sulfate (SDS) as the reference toxicant [l]. (SDS) as the reference toxicant [l]. 

Test 

Number --- 

1 

2 

3 

4 

5 

n: 4 5 5 

Mean: 1.4 1.73 2.38 

CV(%): NA 1 29.7 23.3 

NOEC Range: 1.2 - 3.3 mg/l (this represents a difference of one exposure 

concentration). 

SDS concentrations for all tests were 0.9, 1.8, 3.6, 7.2, and 14.4 mg/l. 

Prepared by Florence Kessler, TAI, Cincinnati, OH, January 11, 1990 (ICp 

Program, version 1 ,l b). 

NOEC Range: 0.9 - 1.8 n-g/l (this represents a difference of one exposure 

concentration). 

Prepared by Elise Torello, WC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1 .l b). 

Test 

Number - 

1 

2 

3 

4 

5 

n: 

Mean: 

cv(%): 

: 

I 

NOEC 

b%lm 

12.2 

12.2 

24.4 

~6.1 

6.1 

4 

13.7 

NA 

30.3 46.3 

26.2 34.1 

11.2 17.2 

-,- 

5 5 

22.8 29.9 

41.9 48.2 

A-l -5 
RED MACROALGAE(C~~~~~~ga~~~~ 

Reproduction Test Single Laboratory Precision Data 

Table A-l-16. Single laboratory precision of the red 

macroalga (Champio porvu/u) reproduction test performed in 

SO/SO natural seawater and GP-2 artificial seawater. Copper is 

the reference toxicant [l]. 

Test NOEC ] lCLs 

Number , WI/u WIiiu 

1 I 1.0 1.67 

c - 

NOEC Range: 0.5 - 1 .O ug/l (this represents a difference of one exposure 

concentration). 

Prepared by Elise Torello, SAIC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (ICp Program, version 1.1 b). 

Table A-1-17. Single laboratory precision of the red 

macroalga (Chompio porvulu) reproduction test performed in 

50/50 natural seawater and GP-2 artificial seawater. Sodium 

dodecyl sulfate (SDS) is the reference toxicant [l] (personal 

communication with G. Thursby, SAIC, Narragansett, RI). 

Test 

Number 

1 

2 

3 

4 

5 

6 

7 

8 

9 

n: 

Mean: 

CV(%): 

NOEC 

+ 

co.48 0.4 

co.48 0.2 

0.26 

; 

0.2 

0.09 I 0.1 

0.16 0.2 

0.09 i 0.1 

<0.29 I 0.3 

5 9 

0.22 I 0.31 

NA I 69.0 

1 

0.3 

0.6 

0.2 

0.4 

0.5 

0.3 

0.3 

0.2 

0.4 

9 

0.36 

37.0 

NOEC Range: 0.09 - 0.48 mg/l (this represents a difference of two exposure 

concentrations). 

Prepared by Elise Torelfo, SAIC, Narragansett, RI, and Margarete Heber, EPA, and 

Washington, DC, February 1990 (IQ Program, version 1.1 b). 

Table A-1-18. Single laboratory precision testing of the red macroal a (Chompia porvulo) reproduction test in natural seawater (30 

OJOO salinity). The reference toxicants used were copper sulfate (Cu) P g2 and sodium dodecyl suffate (SDS)2t3 [7]. 

cu @g/l) SDS (mg/l) __---- 

Test r -NOEC 1 Gs I ‘CSO NOEC GS GO 

CV(%): 1 NA 1 61.09 ’ 34.45 1 NA 1 62.29 1 22.92 

‘Copper concentrations were OS, 1 .O, 2.5, 5.0, 7.5, and 10 ugll. Concentrations of Cu were made from a 100 ug/ml CuSO4 standard obtained from Inorganic Ventures, 

Inc., Brick, NJ. 

2All tests were conducted at 23 + l°C in natural seawater with irradiance set at 40 uE/m’,‘s. 

%DS concentrations were 0.0375, 0.075, 0.15, 0.30, 0.60, and 1.20 mg/l. Concentrations of SDS were made from a 44.64 + 3.33 mg/ml standard obtained from U.S. EPAEMSL, Crncinnati, OH. 

Prepared by Steven H. Ward and Glen Thursby, EPA, Narragansett, RI (ICp Program, version 1 .l b). 

A-l -6 
FRESH WATER SHORT-TERM CHRONIC TOXICITY TESTS 
FATHEAD MIWWDW (Pimephales promelas) 

Seven-day Larval Survival and Growth Test and 

Embryo-larval Survival and Teratogenicity Test 

Single Laboratory Precision Data 

Table A-1-19. Single laboratory precision of the fathead 

minnow (Pimepholes promelos) embryo-larval survival and 

teratogenicity test performed in using Diquat as the reference 

toxicant [2]. 

I Test I LCl I 

2 2.31 

3 1 so 

4 1.71 

5 1.43 ~ 

n: 5 

Mean: 1 Sl 

CV(%): 41.3 

Table A-1-20. Single laboratory precision of the fathead 

minnow (Pimephales promelos) embryo-larval survival and 

teratogenicity test performed in using cadmium chloride as the 

reference toxicant (21. 

Test 

Number 

1 --4 

2 

3 

4 I 

0.014 

0.006 

0.005 

0.003 

5 -- -- ~~..OEL 

n: 5 

Mean: 0.0068 0.012 

CV(%): 62 NA 

NOEC Range: 0.011 _ 0.013 mg/l (this represents a difference of one exposure 

concentration). 

A-l-7 
FATHEAD MINNOW (Pimephaks prume/as) 

Seven-day Larval Survival and Growth Test 

Single Laboratory Precision Data 

Table A-l-21. Single laboratory precision of the fathead 

minnow (Pimephales promelos) larval survival and growth test 

performed in using NAPCP as the reference toxicant [2]. 

Test NOEC* 

Number (WI) 

1 256 

2 128 

3 256 

4 128 

5 128 

n: 5 

Mean: 

cv(%): 

I 179.2 

NA 

*Raw data unavailable, It25 and Itso values could not be calculated. 

NOEC Range: 128 _ 256 ug/l (this represents a difference of one exposure 

concentration). 

Table A-l-22. Results of the performance evaluation for contract laboratories conducted for the California Regional Water Quality 

Control Board. All tests were conducted using potassium chromate (expressed as Cr+6) and testing the fathead minnow (Pimephales 

promelos) in the 7-day subchronic tests [3]. 

Lab - 

l ! Tap’ ! 2X 

2 

3 

4 

5 

6 I 

7 ’ 

8 

9 MHRW ! 3X 

10 - - _. - --..- .- 

Mean: 

cv (%): I 

’ Moderately hard tap water 

2 Control with three replicates and all concentrations with two replicates. 

3 Value is extrapolated and is not included in coefficient of variation calculation. 

4 Weight measurements made with questionable techniques. 

’ Dechlorinated Lake Ontario tap water. 

6 Not reported. 

’ Well water mixed with spring water, moderately hard. 

’ Value may be skewed as middle concentration had 45 percent survival but no weights reported. 

A-l-8 
Seven-day larval Survival and Growth Test 

Interlaboratory Precision Data 

Table A-l-23. lnterlaboratorv orecision data of the fathead minnow 1Pimeohale.s oromelas) 7-dav larval survival and orowth test. 

Combined frequency distribution for survival NOECs for all participatkg kboratdries [2]. ’ ’ 

a 

NOEC Frequency (%) Distribution .- 

Tests with 2 Reps Tests with 4 Reps 

Sample 

Sodium Pentachlorophenate ’ 

l--.--.-L 

Median 1 +1(a) 

35 53 

Sodium Pentachlorophenate 2 42 

Potassium Dichromate 1 47 

Potassium Dichromate 2 41 

Refinery Effluent 301 26 

Refinery Effluent 401 37 

Utility Waste 501 56 

42 

47 

41 

68 

53 

33 

’ Percent of values with one concentration intervals of the median. 

’ Percent of values within two or more concentrations intervals of the median. 

11 56 33 11 

Table A-l-24. Interlaboratory precision data of the fathead minnow (Pimephales promelos) 7-day larval survival and growth test. 

Combined frequency distribution for weight NOECs for all participating laboratories [2]. 

NOEC Frequency (46) Distribution 

I ---~--~~-- Tests with 2 Reps rtTests with 4 Reps 

- Median ~ r *I(a) .- >Z(b) -~. - 

*l(a) >W) 

41 0 

63 f 0 

47 18 

47 41 

53 12 

47 16 : 33 I 56 1 11 

61 I 28 33 I 56 ’ 11 

I 

57 43 0 

22 45 33 

88 0 63 25 j :: 

75 I 25 0 

Sample Median 

- 

__~ .~ .-~ 

Sodium Pentachlorophenate 1 59 

Sodium Pentachlorophenate * 37 

Potassium Dichromate 1 35 

Potassium Dichromate 2 d--- 12 

Refinery Effluent 301 I ;; Refinery Effluent 401 

Utility Waste 501 11 

’ Percent of values with one concentration intervals of the median. 

’ Percent of values within two or more concentrations intervals of the median. 

A-l -9 
CERIODAPHMA (Ceriodaphnia dubia] 

Seven-day Reproduction Test 

Single Laboratory Precision Data 

Table A-1-25. Single laboratory precrsion of (Cerioduphnio dubio) 

reproduction test performed in using sodium pentachlorophenol as the reference toxicant [2]. 

Table A-1-26. Single laboratory precision, from six discrete laboratories, of the (Ceriodophnio dubia) reproduction test performed using sodium 

chloride (NaCI) as the reference toxicant. Tests were conducted in 1989 [4]. 

Test Number NOEC 

@W) 

lC25 IGO 

(w/U (mg/l) -- -~ .- -- 

19 0.30 

I 

0.3754 0.4508 

46A 0.20 0.0938 0.2608 

460 0.20 0.2213 0.2897 I 

49 0.20 0.2303 0.2912 

55 0.20 0.2306 0.3177 

56 0.10 0.1345 0.1744 

57 0.20 0.2241 ' 0.2827 

n: 7 7 7 

Mean: 0.20 I 0.2157 0.2953 

CV(%): , NA , 41.1 27.9 

NOEC Range: 0.25 - 0.30 mgil (these values all fell within the same 

concentration range). 

Prepared by Florence Kessler, TAI, Cincinnati, OH, fanuary 11, 1990 (ICp 

Program, version 1 .l b). 

laboratory 

Test NOEC 

Number 

k!5 , (mg/l) 1 (mg/l) 1 (rug/l) ‘Go 

A 0.77 

1.34 

1.32 

4 l.ooR ’ 0.67 1.28 

--F 

n: 

Mean: 

4 ! 0.50~ 

5 1 .oOR 

-.- -. 6- 

n: 

-. t +!L 

/ 

Mean: 

CV(%): 

--c -T 

i y:“’ 

; 1 .OOs 

o.50s 

i 3 

4 

I I.$ 

5 I 1 .oos 

1.31 

1.12 

6 

1.04 

24.11 

1.23 

0.46 

1.25 

1.13 

1.22 

0.69 0.88 

0.81 ' 1.16 

1.84 

1.57 ..- - - 

! 6 

1 

1.43 

24.37 -. - 

1.49 

1.02 

1.50 

1.44 

1.49 

6 1 .oos 1.21 ! 1.51 - -. - - _-. _ - ._ -*- - -.-- 

n: 

Mean: ( ! i.83 Y.13 ! Y.41 

CV(%) : NA 16.54 1 13.62 

R = Reproduction was the most sensitrve endpoint. 

5 = Survival was the most sensitive endpoint. 

Test NOEC 

Laboratory Number (w/l) 

IQ5 

(w/l) 

D 1 0.50R 

2 0.2SR 

3 1 .oos 

4 1 .oOs 

5 1.00s 

0.58 

0.30 

0.84 

1.04 

I 1.04 4 -- 6 -L - OSOR -r-L. 0 76 

n: 6 

Mean: 0.71 1 60.76 

-. - "'A 37.55 

1 1 .oosq 0.44 

4 ' 1.00~ 

5 1 .oos I 

- 

1.04 

1.06 

1.13 

1.13 

1.19 -- 

6 

1.00 

27.96 

0.61 

0.63 

0.66 

0.65 

IC50 

(mg/O 

0.84 

0.60 

1.22 

1.38 

1.37 

1.14 --. 

6 

1.08 

28.56 

0.74 

1.37 

1.37 

1.42 

1.42 

1.46 -- 

6 

1.30 

21 20 -L 

1.13 

1.20 

0.83 

0.81 

Prepared by William Peltier, EPA, Region IV, November 28, 1990 (ICp Program, version 1 ,l b). 

A-1-10 
CERlODAPHulA (Curiodaplinia dubid 

Seven-day Larval Reproduction Test Interlaboratory Precision Data 

Table A-l-27. Interlaboratory precision of (Cerioduphnio dubia) 

reproduction test, using sodium chloride (NaCI) as the 

reference toxicant. The single lab precision data are presented 

in the preceding table [4]. - 

Laboratory 

A 

B 

C 

~ 

D 

E 

F 

n: 

Mean: 

a/(%): 

NOEC 

ml/l) 

0.83 

0.83 

0.83 

0.71 

1.00 

0.50 

6 

0.80 

NA 

0.89 1.26 

1.04 1.43 

1.13 1.41 

0.76 1.09 

1 .oo 1.30 

0.63 0.95 - 

6 I 6 

0.91 ! 1.24 

20.53 15.17 

Prepared by William Peltier, EPA, Region IV, November 28, 

1990 (ICp Program, version 1 .l b). 

Table A-l-28 Interlaboratory precision of (Ceriodo 

reproduction test, using an industrial effluent as t f: 

hnia dub) 

e reference 

toxicant and sodium chloride (NaCI) as a reference toxicant. 

Tests were conducted in May 1987 [ 31. 

Effluent Reference Toxlcant 

Lab Go w lC25 w ICm (%,I ii, (96) 

A 6.20 4.9 33.0 -- - il.8 

B 8.40 6.2 38.8 30.8 

D 7.69 5.8 36.3 29.4 

E 6.34 5.0 36.6 28.0 

F 4.00 1.2 8.1* 1.21* 

I 2.84 1.9 35.1 25.2 

K 6.89 5.3 18.4 13.2 

M 5.70 1.9 38.1 31 .o 

N 7.43 5.9 27.8 10.4 

0 0.04’ 0.02* 35.1 27.3 -^.-. 

t-l: 9 9 

Mean: ’ z.17 I.4 32.8 24.1 

CV(%): 29 67 21 31 

‘Values were excluded from mean calculations because they fell outside of + 2 

standard deviations. For this reason, these values are considered statistical 

outliers and, according to EPA’s toxicity methods guidance [2] on reference 

toxicant control charts, are excluded. 

Table A-l-29. Results of the performance evaluation for contract laboratories conducted for the California Regional Water Quality 

Control Board. All tests were conducted using sodium chloride and testing Cerioduphnio dobiu in the 7-day chronic 

tests 131. 

I / X Young/ h5 KU NOEC 

Lab Water ’ Age Control ’ (g/l NaCI) Endpt 

1 ’ Tap1 YCT/Algae 0-4;<24 1 7.80.202 (0.14-0.35) -- co.25 R 

2 Hard W3 TF/Algae O-4 26.51.3 (0.78-l .7) 1.0 R 

3 DMW4 YCT/Algae O-6 24.90.21 2 (0.17-0.54) <0.25 R 

4 Tap5 YCT o-4 17.20.49 (0.35-l .O) 0.5 R 

5 HRW YCT 0-4;<24 19.80.42 (0.20-I .I) 0.5 R 

6 Surface6 YCT/Algae O-6 14.80.90 (0.66-l .l) 0.25 R 

7 MHRW YCT/Algae 4-8 17.20.56 (0.24-0.64) 0.25 R 

8 MHRW YCT ~24 16.80.21 2 (0.11-o. 32) 0.25 R 

9 MHRW YCT O-4 12.80.71 (0.56-0.81) 0.50 R 

10 DMw4 YAT/Algae o-4 4 31 so.91 (0.45-l .l ) 1.0 R 

Mean: O.-j6 

CV(%): j 40 

’ Moderately hard tap water. MHRW = Moderately hard reconstituted water 

’ Dose response curve limited. HRW = Hard reconstituted water 

3 Hard well water. WV = Well water 

4 Ten percent diluted mineral water. YCT = Yeast-Cerophyl-Trout chow 

5 Dechlorinated Cake Ontario tap water. YAT = Yeast-Alfalfa-Trout chow 

6 Briones reservoir water. TF = Trout food suspension 

R = Reproductive endpoint Algae = S&nostrum capricornotum 

A-l -11 
CERIODAPHRIA (Cerhdapnnia dubiaj (contlnued) 

Seven-day Larval Reproduction Test Interlaboratory Precision Data 

Table A-1-30. Interlaboratory precision data for Ceriodophniu dubiu summarized for 

eight materials, including reference toxicants and effluents [S]. 

Test Mean 

Material ’ I& 

Sodium chloride 1.34 

Industrial 

Sodium chloride 

Pulp & Paper 

Potassium dichromate 

Pulp & Paper 

Potassium dichromate 

Industrial 

Mean 

cv 46 GS cv % / 

29.9 1 1.00 34.3 

3.4 : 83.3 

I I I 

3.2 78.1 

0.96 57.4 0.90 44.4 

60.0 28.3 47.3 27.0 

35.8 23.4 32.7 

70.2 55.7 f2.2 

53.2 29.3 46.8 

69.8 67.3 36.7 ~-. I 8 I 8 37.5 39.0 

1 Standard Deviation: 1 23.0 19.1 

SELEHASTRUM CA PRICORUUTUM 

Growth Test 

Single Laboratory Precision Data 

Table A-1-31. Single laboratory precision of (Selenastrum 

cupricorrrufum) growth test performed in using cadmium as 

the reference toxicant [2]. 

Test I 

Number 1 

1 2.3 

2 2.4 

3 2.3 

4 2.8 

5 2.6 

6 2.1 

7 2.1 

8 2.1 

1 ii;: ; iI;7 8.42 

44.1 

‘Outlier values are excltided from mean because they fell outside of a QA 

control table for these reference toxicants. 

Control Variation 

(%Cv) 

4.8 

9.6 

5.5 

13.3 

4.4 

8.2 

14.4 

7.1 

11.9 

5.0 

36.4’ 

77.8’ 

Note: Sodium chloride concentrations were 1, 2, 4, 8, and 16 g/l in all tests. 

Prepared by Dr. Cornelius Weber, EPA, Cincinatti, OH, March 15, 1991. 

A-1-12 
APPENDIX A-2 

EFFLUENT VARIABILITY DATA 
Table A-2-1. Percent mortality in 100 percent collected 1989 

by grab method (personal communication W. Pettier, EPA, 

Athens, GA). Results indicate variability over 24 hours and 

differences in species sensitivity over time. Tests were 

1830 

0030 

0630 

1230 

1830 

0030 

7/26/89 0630 0 

1830 0 

0030 0 

1230 0 

Date 

3/07/89 

3/07/89 

3/08/89 

3/08/89 

3/20/89 

3/20/89 

3/21/89 

3/21/89 

6/19/89 

6/19/89 

6/20/89 

D. pulex 

15 

85 

65 

30 

0 

100 

95 

70 

5 

40 

100 

100 

0 

100 

100 

55 

Time P. promelas 

1230 0 

conducted according to methods described in Reference 6. 

% Mortality in 100% Effluent 

C. dubia 

100 

100 

100 

80 

100 

100 

100 

100 

100 

100 

100 

100 

100 

100 

100 

100 

0 

0 

0 

0 

0 

0 

6/20/89 0630 0 

7125189 1230 0 

7/25/89 1830 0 

7126189 0030 0 

Table A-2-2. LC50s for a POTW effluent over 17 months. All 

tests were conducted using Ceriodaphnia dubio and tests were 

run for 48 hours. All tests were conducted according to the 

methods described in Reference 6. Dates with roman numeral 

notation mean that more than one sample was collected at 

different times over a short interval (1 to 2 days). (Data 

source: [8].) 

Sample Date 48 hours LC50 (%) 

08/23/86-I 71 

03/09/87-I 71 

05/02/87-I 35 

05/03/87-I 65 

05/04/87-I 71 

05/23/87-I 71 

05/23/87-II 71 

05/23/87-III 61 

06/27/87-I 36 

06/27/87-II 41 

06/27/87-III 18 

09/22/87-I 71 

12/18/87-I 87 

01/05/88-I 68 

01/05/88-II 63 

Mean LC50: 60.0 

cv (%): 31.1 

n: 15 

Table A-2-3. LC50s for a POTW effluent over 7 months. All 

tests were conducted using Ceriodaphnia dubia and tests were 

run for 48 hours. All tests were conducted according to the 

methods described in Reference 6. Dates with roman numeral 

notation mean that more than one sample was collected at 

different times over a short interval (1 to 2 days). (Data 

source: [8].) 

Sample Date 

10/06/87-I 

10/06/87-II 

10/06/87-III 

10/30/87-I 

12/03/87-I 

12/03/87-II 

01/12/88-I 

01/13/88-I 

02/03/88-IX 

02/03/88-X 

03/03/88-III 

03/03/88-IV 

03/23/88-I 

03/23/88-II 

04/28/88-I 

04/28/88-II 

05/17/88-I 

05/17/88-II 

Mean LC50: 

cv (%): 

n: 

48 hours LC50 (%) 

71 

71 

71 

87 

61 

35 

61 

58 

50 

50 

87 

81 

25 

35 

50 

55 

61 

35 

58.0 

31.4 

18 

A-2-1 
Table A-2-4. LCsOs for a POlW effluent over 12 months. 

Tests were conducted using either Ceriodaphnia dubia or 

fathead minnows or both. Ceriodaphnia tests were conducted 

for 48 hours while fathead minnow tests were 96 hours. Both 

the 4%hour and 96-hour fathead minnow results are shown in 

order to evaluate how the LCses for the two species compare. 

All tests were conducted according to the methods described 

in Reference 6. Dates with roman numeral notation mean that 

more than one sample was collected at different times over a 

short interval (1 to 2 days). (Data source: [8].) 

Table A-2-5. LCsOs for a POTS effluent over 4 months. 

Tests were conducted using either Ceriodaphnia dubia or 

fathead minnows or both. Ceriodophnio tests were conducted 

for 48 hours while fathead minnow tests were 96 hours. Both 

the 48-hour and g&hour fathead minnow results are shown in 

order to evaluate how the LCsOs for the two species compare. 

All tests were conducted according to the methods described 

in Reference 6. Dates with roman numeral notation mean that 

more than one sample was collected at different times over a 

short interval (1 to 2 days). (Data source: (El].) 

i _______ LCEFL-------- 

Sample Date ! C. dubia P. promelas 

- 48 hours 48 hours ’ 96 hours -.- --- , 1 

03/16/88-1 , 62 

+--s---i--T--- 

06/09/88-l 18 

* ’ -* 

09/08/88-l I 68 >lOO ; >lOO 

10/04/88-l ’ 61 -* l I -1 

10/04/88-II 63 

12/l 4/88-l , 70 /58 1 34 

12/l 4/88-II 17 I 60 41 

02/17/89-l ) 35 I 61 39 I 

02/l 7/89-II 1 35 I 61 I 37 

03/22/89-l 35 81 64 

03/22/89-II ! 47 I 61 I 40 

Mean LCs0: 46 I 59.6 ’ 40.0 

CV (%): ! 42 22.4 I 29.7 

n: 

I 11 ; 7 I 7 

l Data not available. 

Note: Greater than (>) values were excluded from the mean LCc,o calculation. 

c __-__ &cl (W -__ Sample Date, C. dubicl , P. promelos 

&#fy; I !!;oclz;7z. 

1 l/l 5/88-f ’ 92’ / 67 1 37 

11/16/88-l 61 >lOO I 100 

1 l/30/88-11 >lOO >lOO I 33 

11/30/88-Ill 95 >lOO , >lOO 

12/08/88-l 100 I 87 54 

12/08/8&ll , >lOO ’ 87 / 53 

12/13/88-l j 90 >I00 

I 

77 

12/l 3/88-II 87 , 85 51 

01 /10/89-l 75 58 ; -* 

01 /10/89-h 61 ’ 41 l 

-- 

I 

01 /19/89-l I 100 88 I 68 

01/19/89-II I 87 84 69 

01/25/89-l >lOO 

01/25/89-II 1 95 

87 I 64 

85 I 56 

01/31/89-l , 90 70 I 60 

01/31/89-II 

I 

63 70 I 60 ---- ----- ---------- 

-Mean: 

_---- 

78.4 75.8 - - 61.3 

cv (%): 33.1 19.6 I 27.7 

It 14 12 14 

*Not obtained. 

Note: Greater than (>) values were not included in the mean LCso calculation. 

A-2-2 
Table A-2-6. NOECs for a POlW effluent conducted 20 times 

over 1 year. All tests were conducted using Chompia parvulo 

according to methods described in Reference 1. All effluent 

samples were 24-hour composites collected post-chlorination. 

(personnal communication-Glen Thursby, SAIC, 

Narragansett, RI). 

Table A-2-7. NOECs for a POTW effluent over 1 year. All 

tests used Arbocia punctulata according to methods described 

in Reference 1. All effluent samples were 24-hour composites 

collected post-chlorination. (Data source: ERL-Narragansett, 

RI.) 

% Effluent -- -- -. .~-~ 

ICE I& i NOEC .~. - ___ .- .- 

12/09/85 

12/l O/85 

12/l l/85 

12/l 2/85 0.41 

12/l 3/85 3.09 

12/l 5185 2.16 

07/l 6186 2.99 

07/l 7186 3.59 

07/l B/86 .44 

07/l 9186 .47 

07/20/86 .24 

07/21/86 .ll 

07/22/l-36 

9/09/86 

09/l O/86 

09/l l/86 

09/l 2186 

09114186 ! .25 ! 1.76 ~. .~. 1 

0.65 1.23 

0.38 I 0.76 

0.69 1.50 

0.82 

I 4.12 

4.09 

4.33 

4.68 

4.76 

3.41 

3.98 

3.20 

.84 5.19 

.07 3.02 

.l 7 4.13 

.73 3.62 

.57 1.89 

l-i: 

Mean: 

I 18 18 18 

2.2 3.1 I 4.2 

1.25 

1.25 

2.50 

1.25 

5.00 

5.00 

5.00 

5.00 

5.00 

5.00 

7.50 

5.00 

5.00 

2.50 

7.50 

7.50 

1.25 

2.50 

cv (46): / 52.8 / 46.8 1 NA 

Table A-2-8. NOECs for a POlW effluent over 1 year. All 

tests used Mysidopsis bahia according to methods described in 

Reference 1. All effluent samples were 24-hour composites 

collected post-chlorination. (Data source: ERL-Narraqansett, 

RI.) . 

016 Effluent 

12/09 - 12/l 6/85 

n: 4 ,4 

R-Reproductive endpoint 

S-Suwval endpoint 

G-Growth endpoint 

Test Date 

--I 12fO9f 85 

12/l Of85 

12/l l/85 

12/l 2185 

12/l 3185 

12/14/85 

12/l 5185 

07/l 6/86 

07/l 7186 

07/l 8186 

07/l 9/86 

07/20/86 

07/21 I86 

07/22/86 

09/09/86 

09/l l/86 

09/l 2186 

09/l 3f86 

09f 14186 

09/l 5/86 

11/11/86 

11 /13/86 

1 l/14/86 

11/15/86 

Mean: 

cv (96): 

n: , 24 , 24 11 

I.- - --- -- bi 

1.09 4 

1.41 

0.75 

3.28 

2.65 

1.11 

1.29 

0.17 

0.21 

0.63 

1.09 

0.54 

0.40 

0.40 

0.31 

0.47 

0.21 

3.30 

0.23 

0.10 

0.27 

0.88 

0.82 

0.34 

0.91 

101.3 

% Effluent 

kl 

1.71 

2.84 

1.09 

4.06 

5.32 

1.60 

1.84 

0.35 

0.46 

0.86 

1.68 

1.13 

0.58 

0.56 

0.41 

0.79 

0.48 

5.42 

0.35 

0.15 

0.54 

1.48 

1.61 

0.56 __- 

1.49 

96.9 

.-. - NOEC 

0.65 

0.65 

0.65 

1.30 

2.50 

0.65 

0.65 

<0.30 

<0.30 

<0.30 

<0.30 

<0.30 

<0.30 

<0.30 

<0.30 

<0.60 

<0.20 

1.30 

<0.20 

<0.20 

1.30 

0.30 

0.60 

<0.30 

I / 0.95 

NA 

Note: Less than (<) values wete excluded from CV and mean NOEC calculations. 

A-2-3 
Table A-2-9. NOECs for a POTW effluent over 1 year. All 

tests used Menidiu beryllino according to methods described 

in Reference 1. All effluent samples were 24-hour composites 

collected post-chlorination. (Data source: ERL-Narragansett, 

RI.) 

ll/ll - 11/18/86 --- 

Mean: 

cv (%): 

n: 

NC - Value is not calculable. 

NC 10.0 

14.9 20.8 10.0 

4.3 3.0 NA 

3 3 4 

Table A-2-10. LC5Os for a refinery effluent over 14 months. 

Tests were conducted using either Ceriodaphnio dubia or 

fathead minnows Pimepholes promelas or both. Ceriodophnia 

tests were conducted for 48 hours while fathead minnow tests 

were 96 hours. Both the 48-hour and 96hour fathead minnow 

results are shown in order to evaluate how the LC5Os for the 

two species compare. All tests were conducted according to 

the methods described in Reference 6. Dates with roman 

numeral notation mean that more than one sample was 

collected at different times over a short interval (1 to 2 

days). (Data source: [8].) 

01/05/88 

02/09/88-l 

02/09/88-l 

03/02/88-l 

03/02/88-II 

03/24/88-l 

05/06/88-l 

07/l 4/88-l 

I <12 38 

35 35 

35 

t 

55 61 

07/28/88-l , 37 I 35 22 

- - --___ 

.- -.- 

12/01/87 / 15 

19 

<12 

cl2 l 

l 

t 

l 

25 

07/28/88-II 

09/29/88-l 

12/01/88-l 

12/07/88-l 

01/27/89-l 

01/27/89-/l 

28 31 I 

41 

75 

’ 

39 

56 

18 67 

I 

~25 

25 

34 

13 

100 61 

71 60 

03/23/89-l 1 58 ’ 54 20 

--------+- 

Mean LCsO: 43 I 45 24 

cv (%): 

1 

54 28 I 32 

n: 16 15 10 

l Data not available 

Note: Less than values excluded from mean LCSO calculations 

Table A-2-11. LC5Os for a refinery effluent conducted over 6 

months using fathead minnows (Pimephales promeias), 

Ceriodophnia dubio, and mysids (Mysidopsis bahio), according 

to methods described in Reference 6. (Data source: Dorn, 

1989.) 

4/l 7186 71.2 37.2 

4123186 , 71.8 35.9 38 -. 0 

5/14/86 82.0 38.7 I 35.8 

5/28/86 65.4 22.0 

6/l l/86 82.0 I - 24.7 

Mean NOLC: 66.3 32.9 ’ 32.8 

cv (%): ! 18.7 19.5 21.6 

n: 1 11 10 3 

Table A-2-12. NOECs for a refinery effluent conducted over 6 

months using fathead minnows (Pimepholes promelos), 

Ceriodaphnio dubia, and mysids (Mysidopsis bahia), according 

to methods described in References 1 and 2. (Data source: 

Dorn, 1989.) 

3/ 19186 10.1 14.1 

4/02/86 18.0 14.1 - 

A-2-4 
Table A-2-13. LCsos for a manufacturing effluent conducted over 2 

ears. All tests were conducted using Dophnio mo 

methods described in Reference 6. (Data source: [8 4 

no according to 

.) 

Test Date (% Siient) 

1982 (1 st quarter) 56 

1982 (4th quarter) 90 

1982 (4th quarter) 70 

1983 (3rd quarter) 69 

1983 (3rd quarter) 36 

1983 (3rd quarter) 36 

1983 (3rd quarter) 32 

1983 (3rd quarter) <ia 

1983 (3rd quarter) 28 

1983 (3rd quarter) 67 

1983 (3rd quarter) <lO 

1983 (4th quarter) 46 

1983 (4th quarter) 75 

1983 (4th quarter) 78 

1983 (4th quarter) 24 

1983 (4th quarter) 26 

1983 (4th quarter) 32 

1983 (4th quarter) 19 

Mean LCso: 45.1 k24.3 

cv (%): 53.9 

n: la 

Note: Less than (<) values were excluded from the mean LCso calculations. 

Table A-2-14. LCgy for a manufacturing effluent conducted over 8 

All tests were conducted using Pimephales promelas according r?%thods described in Reference 6. (Data source: [8].) 

Test Date 

1979 (1st quarter) 72.0 

1979 (1 st quarter) 62.0 

1979 (1 st quarter) 52.0 

1979 (3rd quarter) 39.0 

1981 (2nd quarter) 64.0 

1981 (4th quarter) 70.0 

1982 (2nd quarter) 44.0 

1982 (2nd quarter) 66.0 

I985 (1 st quarter) 59.6 

I985 (4th quarter) >lOO.O 

I986 (2nd quarter) I 49.2 

I986 (2nd quarter) 63.8 

I986 (2nd quarter) 50.0 

I986 (3rd quarter) 75.7 

I986 (3rd quarter) 80.0 

I986 (3rd quarter) 79.0 

1986 (4th quarter) 71 .o 

Wean LCso: 64.5 + 15.1 

zv (%): 23.5 

1: 17 

Note: Greater than (>) values were excluded from the mean LCso calculations. 

Table A-2-15. LC5Os for a manufacturing effluent conducted 

over 5 years. All tests were conducted using Pimephales 

promelos according to methods described in Reference 6. 

(Data source: [a].) 

I 

Test Date (% Zent) 

1980 (1 st quarter) 18.0 

1980 (2nd quarter) 11 .o 

1980 (3rd quarter) 32.0 

1980 (4th quarter) 16.0 

1981 (1 st quarter) 32.0 

1981 (2nd quarter) 

1981 (3rd quarter) 

1981 (4th quarter) 

1982 (1 st quarter) 

1982 (2nd quarter) 

1982 (3rd quarter) 

1982 (4th quarter) 

1983 (1 st quarter) 

1983 (2nd quarter) 

1983 (3rd quarter) 

23.0 

17.0 

46.0 

9.0 

32.0 

28.0 

52.0 

34.0 

33.0 

20.0 

A-2-5 

1983 (4th quarter) 43.0 

1984 (1 st quarter) 45.0 

1984 (2nd quarter) 19.0 

1984 (3rd quarter) 61 .O 

Table A-2-16. LC5os for a manufacturing effluent conducted 

over 5 years. All tests were conducted using Daphnio magna 

according to methods described in Reference 6. (Data source: 

PI.) 

Test Date I --._B .~.. 

981 (2nd quarter) 100.0 

981 (3rd quarter) I >lOO.O 

982 (3rd quarter) >lOO.O 

984 (4th quarter) 80.0 

985 (1 st quarter) 75.0 

1986 (1 st quarter) 25.0 

1986 (2nd quarter) 82.0 

1987 (1 st quarter) 75.0 

1987 (1 st quarter) I 24.0 

1987 (1 st quarter) ,100.o 

,100.o 

65.9 + 29.5 

44.8 

n: I 11 

Note: Greater than (>) values were excluded from the mean LCc,o calculations. 
Table A-2-17. LC5Os for a manufacturing effluent conducted 

over 7 years. Ail tests were conducted using Uaphnio pulex 

according to methods described in Reference 6. (Data source: 

Table A-2-18. LC5Os for a manufacturing effluent conducted 

over 3 months. All tests were conducted using Daphnio 

mogno according to methods described in Reference 6. (Data 

source: [8].) 

Test Date (% kkent) 

1980 (izquarter) -- - 

-. .-- - ~ 

55.0 

1980 (4th quarter) 33.0 

1981 (I st quarter) 60.0 

1981 (1 st quarter) 24.0 

1981 (1 st quarter) >lOO.O 

1981 (2nd quarter) >lOO.O 

1981 (3rd quarter) >lOO.O 

1982 (3rd quarter) 

1 

1986 (3rd quarter) 

1986 (3rd quarter) -1. 

2100.0 

>lOO.O 

>lOO.O - - .- - 

Mean LCse: 43.0 + 17.3 

cv (%): 40.2 

n: 10 

Note: Greater than (>) values were excluded from the mean CC50 calculations. 

Test Date I (96 EL) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

982 (4th quarter) 

1982 (4th quarter) 

Mean LCso: 

cv (96): 

n: 

I 

>lOO.O 

81 .O 

I 57.0 

61 .O 

87.0 

90.0 

90.0 

>lOO.O 

z-1 00.0 

54.0 

74.0 

I >lOO.O 

74.3 * 15.1 

20.3 

12 

Note: Greater than (P) values were excluded from the mean LCso calculations. 

A-2-6 
APPENDIX A-3 

ACUTE-TO-CHRONIC RATIO DATA 
Table A-3-1. Example of Acute-to-Chronic Ratios 

Oil Refinery1 

Mean ACR: 

n: 

Range: 

Fathead 

Minnow 

1.89 

3.47 

2.60 

2.87 

2.33 

2.43 

5.26 

5.08 

2.74 

3.11 

5.1 

Ceriodaphnia 

9.09 

3.89 

6.58 

3.63 

6.91 

7.05 

7.11 

3.63 

2.59 

5.5 

4.4 

> 10.0 

> 7.1 

> 3.3 

> 2.0 

> 3.0 

2.8 

5.42 

3.3 5.3 

11 13 

1.89-5.26 2.59->10.0 

Mysids 

1.58 

1.49 

1.84 

1.64 

3 

1.49-1.84 

1 Personal communication P. Darn. 

2 Personal communication M.L.C. Ramos and E. Bertoletti (Sao Paulo, Brazil). 

Note: Greater than (>) values were excluded from mean calculations, 

Table A-3-2. Examples of Acute-to-Chronic Ratios 

Chemical Manufacturers 

Mean ACR: 

n: 

Range: 

Fathead 

Minnow 

0.17 

0.07 

8.4 

7.6 

>3.0 

3.9 

>3.0 

1.8 

3.7 

6 

0.07 - 8.4 

Ceriodaphnia 

> 1.0 

> 1.0 

>10.0 

>50.0 

> 2.9 

> 1.4 

1.4 

1.4 

3.9 

2.8 

> 2.0 

> 4.0 

4.0 

1.4 

5.5 

1.8 

> 3.3 

> 3.3 

> 3.3 

1.4 

> 2.0 

5.5 

1.5 

1.4 

5.0 

> 10.0 

> 2.0 

> 3.3 

3.111 

14.01 

4.31 

2.51 

1.81 

5.51 

5.41 

3.72 

20 

1.4->50 

1 Personal communication M.L.L.C. and E. Bertoletti (Sao Paula, Brazil). 

2 Greater than (>) values were excluded from the mean calculation. 

A-3-1 
Table A-3-3. Example of Acute-to-Chronic Ratios 

POTWs 

Fathead I 

Minnow 1 Ceriodaphnia 

1 ::; 5.5 14

I > 

i 13.0 1.8 > 1.0 

1.5 ! 1.0 

2.6 1.8 I 

I 9.3 1.4 

> 1.0 2.0 

> 3.0 2.4 

I 5.3 3.0 

I 3.3 ; 3.0 

5.4 5.5 

I I 

> 3.0 4.9 I 3.0 I > 2.0 

I > 8.0 2I 

/ > 1.0 

> 3.3 

I > 2.0 

4.4 

16.1 

> 4.0 

> 3.3 

>lO.O 

I 2.6 

I 5.7 

2.8 

I 

I 

I >lO.O 

> 2.0 

I 1.4 

I I 2.6 

I > 3.3 

I I 5.5 18

I 1.5 

I I > 3.3 

5.5 

Mean ACR: ; 4.9 ----/- 3.8* 

il: / 11 21 

Range: I 1.5 - 9.3 I 1.4 - 16.1 

l Greater than (>) values were excluded from mean calculations. 

A-3-2 
APPENDIX A 

REFERENCES 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

Weber, Ct. et. al., eds. 1988. Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters 

to Marine and Estuarine Organisms. EPA 600/4-87/028. Office of Research and Development, Cincinnati, OH. 

Weber, C.I. et. al., eds. 1989. Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters 

to Freshwater Organisms, 2d ed. EPA 600/4-89/001. Office of Research and Development, Cincinnati, OH. 

Norberg-King, T.j. Memorandum: Summary of Effluent Toxicity Data for the Technical Support Document for Water 

Quality-based Toxics Control, Chapters 2 and 3. April 11, 1989. U.S. EPA, Environmental Research Laboratory, Duluth, 

MN, to M.A. Heber, U.S. EPA, Enforcement Division, Washington, DC. Memorandum: Technical Support Document for 

Water Quality-based Toxics Control Data: Fathead Minnow Round Robin Data Analyzed to Obtain the IC25s. May 6, 

1990. U.S. EPA, Environmental Research Laboratory, Duluth, MN, to M.A. Heber, U.S. EPA, Enforcement Division, 

Washington, DC, 

Peltier, W. January 23, 1991. Memorandum: Intra- and Interlaboratory Precision Data from Six Laboratories Conducting 

Short-Term Chronic Toxicity Tests Using Ceriodaphnia dubia. U.S. EPA, Region IV, Environmental Services Division, 

Athens, GA, to M.A. Heber, U.S. EPA, Enforcement Division, Washington, D.C. 

DeCraeve, GM., 1.0. Cooney, B.H. Marsh, T.L. Poltock, and N.G. Reichenbach. 1989. Intra- and Interlaboratory Study to 

Determine the Reproducibility of the Seven-day Ceriodaphnia dubia Survival and Reproduction Tests. Battelle, 

Columbus Division, Columbus, OH (in preparation). 

Peltier, W., and Cl. Weber. 1985. Methods for Measuring the Acute Toxicity of Effluents to Aquatic Organisms, 3d ed. 

EPA 600/4-85/013. Office of Research and Development, Cincinnati, OH. 

Ward, S.H. 1990. Technical Report: Procedures for Toxicant Testing and Culture of the Marine Macroalga, Champia 

parvula. U.S. EPA, Region II. 

Norberg-King, T.J. May 4, 1989. Memorandum: Additional Data for the Technical Support Document for Water Qualitybased Toxics Control, Chapters 2 and 3. U.S. EPA, Environmental Research Laboratory, Duluth, MN, to M.A. Heber, U.S. 

EPA, Enforcement Division, Washington, DC. 

A-3-3 
APPENDIX B-1 

SUMMARY OF CLEAN WATER ACT PROVISIONS 
CLEAN WATER ACT (33 U.S.C. 1251 SEQ.) 

Statutory Authority for the Use of Toxicity Testing and Whole Effluent Toxicity 

Limitations in NPDES Permits: 

Over the years, a developmental process has occurred regarding the use of biological techniques to assess 

effluent discharges and set permit limits. The acquisition of data and the development of new techniques has 

contributed to the refinement of toxicity testing methods, thus enabling EPA to more fully act in accordance 

with its mandates to implement statutory requirements relating to the attainment and maintenance of water 

quality. 

Toxicity testing of Whole Effluents and Whole Effluent toxicity limitations in National Pollutant Discharge 

Elimination System (NPDES) permits are essential components in the control of the discharge of toxic 

pollutants to the nation’s waters. The use of toxicity testing and Whole Effluent toxicity limitation in the 

NPDES program is clearly authorized by the Clean Water Act (CWA). 

Relevant provision of the CWA that provide the statutory authority for using toxicity testing and Whole 

Effluent toxicity limitations include the following: 

• 

• 

• 

• 

• 

• 

• 

• 

Section 101 (a) sets forth not only the goal of restoring and maintaining the “chemical, physical, and 

biological integrity of the Nation’s waters” (emphasis added), but also in Section 101(a)(3) the 

national policy of prohibiting the “discharge of toxic pollutants in toxic amounts” (emphasis added). 

As defined at Section 502(15), biological monitoring means that “determination of the effects on 

aquatic life, including accumulation of pollutants in tissue, in receiving waters due to the discharge 

of pollutants (A) by techniques and procedures, including sampling of organisms representative of 

appropriate levels of the food chain appropriate to the volume and the physical, chemical, and 

biological characteristics of the effluent, and (B) at appropriate frequencies and locations.” 

Section 304(a)(8) requires EPA to develop information on methods, including biological monitoring 

and assessment methods, to establish and measure water quality criteria for toxic pollutants on bases 

other than pollutant by pollutant criteria. 

Section 303(c)(2)(8) states, “Nothing in this section shall be construed to limit or delay the use of 

effluent limitations or other permit conditions based on or involving biological monitoring or 

assessment methods...” (emphasis added). 

Section 302(a) provides the authority to establish water quality-based effluent limitations on 

discharges that interfere with the attainment or maintenance of that water quality which shall assure 

protection of public health, public water supplies, and the protection and propagation of a balance 

population of shellfish, fish and wildlife, among other uses. The effluent limitations established 

must reasonably be expected to contribute to attainment or maintenance of such water quality. 

Under Section 301(b)(1)(C) and Section 402, all NPDES permits must comply with any more stringent 

limitations necessary to meet applicable water quality standards, whether numeric or narrative. 

CWA Section 308(a) and Section 402 provide authority to EPA or the Sate to require that NPDES 

permittees/applicants use biological monitoring methods and provide chemical, toxicity, and 

instream biological data when necessary for the establishment of effluent limits, the detection of 

violations, or the assurance of compliance with water quality standards. 

Section 510 provides the authority for states to adopt or enforce any standards or effluent limitations 

for the discharge of pollutants only on the condition that such limitations or standards are no less 

stringent than those in effect under the CWA. 

B-1-1 
APPENDIX B-2 

POLICIES FOR TOXICS CONTROL 
9016 Federal Register / Vol. 49, No. 48 / Friday, March 9, 1984 / Notices 

[OW-FRL-2533-1] 

Development of Water Quality-Based Permit Limitations for Toxic Pollutants; 

National Policy 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Notice. 

SUMMARY: EPA has issued a national 

policy statement entitled “Policy for the 

Development of Water Quality-Based Permit Limitations for Toxic Pollutants.” 

This policy addresses the technical 

approach for assessing and controlling the discharge of toxic substances to the 

Nation’s waters through the National 

Pollutant Discharge Elimination System [NPDES) permit program. 

FOR FURTHER INFORMATION CONTACT: 

Bruce Newton or Rick Brandes, Permits 

Division (EN-336). Office of Water 

Enforcement and Permits. U.S. 

Environmental Protection Agency, Washington. D.C. 20460-7010. 

B-2-1 
Federal Register / Vol. 49, No. 48 / Friday, March 9, 1984 1 Notices 9027 

~UPPLENENTMY INFORMA~~OPK As the 

water pollution control effort in the 

United State8 progresses and the 

“traditional” pollutants (oxygen 

demanding and eutrophying materials) 

become sufficiently treated to protect 

water quatity. attention is shifting 

towards pollutants that impact water 

quality through toxic effects. Compared 

with the traditional pollutants, 

regulation of toxic pollutants is 

considerably more difficult. The 

difficulties include (I) the great number 

of toxic chemicals that may potentially 

be discharged to receiving waters and 

the difficulties in their analysis: [z) the 

changes in the toxic effects of a 

chemical resulting from reactions with 

the matrix of constituents in which it 

exists; and [3) the inability to predict the 

effects of exposure to combinations of 

chemicals. 

To overcome some of these problems. 

EPA and the States have begun to use 

aquatic toxicity tests and various human 

health assessment techniques to 

complement chemical analyses of 

effluents and receiving water samples. 

Because these techniques or their 

application to effluent testing are new, 

EPA and the States have been cautious 

in their use. Based on EPA’s evaluation 

of these techniques and the experiences 

of several States, EPA is now 

recommeding the use of biological 

techniques as a complement to 

chemical-specific analyses to assess 

effluent discharges and express permit 

limitations. EPA has issued these 

recommendations through a statement 

of policy and is developing a technical 

guidance document to help implement 

I he policy. 

The complete test of the national 

policy statement follows: 

Policy for the Development of Water 

Quality-Based Permit Limitations for 

Toxic Pollutants 

Stoten?eni $poIic;, 

To confrr~i pollutants beyond Best 

Available Technology Economically 

Achievable (BAT). secondary treatment. 

and other Clean Water Act technology- based requirements in order to meet 

water quality standard% the 

Environmental Protection Agency (EPA) 

will use an integrated strategy 

consisting of both biological and 

chemical methods to address toxic and 

nonconventional pollutants from 

industrial and municipal sources. Where 

State standards contain numerical 

criteria for toxic pollutants, National 

Pollutent Discharge Elimination System 

(NPDES) permits will contain limits as 

necessary to assure compliance with 

these standards. In addition to enforcing 

specific numerical criteria, EPA and the 

States will use biological techniques and 

avaiiabte data on chemical effects to 

assess toxicity impacts and human 

health hazards based on the general 

standard of “no toxic materials in toxic 

amounts.” 

EPA, in its oversight role, will work 

with States to ensure that these 

techniques are used wherever 

appropriate. Under section 308 and 

section 402 of the Clean Water Act (the 

Act), EPA or the State may require 

NPDES permit applicants to provide 

chemical, toxicity. and instream 

biological data necessary to assure 

compliance with standards. Data 

requirements may be determined on a 

case-by-case basis in consultation with 

the State and the discharger. 

Where violations of water quality 

standards are identified or projected, 

the State will be expected to develop 

water quality-based effluent limits for 

inclusion in any issued permit. Where 

necessary, EPA will develop these limits 

in consultation with the State. Where 

there is a eignificant likelihood of toxic 

effects to biota in the receiving water, 

EPA and the States may impose permit 

limits on effIuent toxicity and may 

require an NPDES permittee to conduct 

a toxicity reduction evaluation. Where 

toxic effects are present but there is a 

significant likelihood that compliance 

with technology-based requirements will 

sufficiently mitigate the effects, EPA and 

the States may require chemical and 

toxicity testing after installation of 

treatment and may reopen the permit to 

incorporate additional limitations if 

needed to meet water quality standards. 

(Toxicity data, which are considered 

“new information” in accordance with 

40 CFR 122.6z(a)(Z]. could constitute 

cause for permit modification where 

necessary.) 

To carry out this policy, EPA Regional 

Administrators will assure that each 

Region has the capability to conduct 

water quality assessments using both 

biological and chemical methods and 

provide technical assistance to the 

States. 

Background 

The Clean Water Act establivhes two 

principal bases for effluent limitations. 

First, existing dischargers are required 

to meet technology-based effluent 

limitations that reflect the best controls 

available considering economic impacts. 

New source dischargers must meet the 

best demonstrated technology-based 

controls. Second, where necessary, 

additional requirements are imposed to 

assure attainment and maintenance of 

water quality standards established by 

the State8 and approved by EPA. In 

0-2-2 

establishing or reviewing NPDES permit 

limits, EPA must ensure that the limits 

will result in the attainment of water 

quality standards and protect 

designated water uses, including an 

adequate margin of safety. 

For toxic and nonconventional 

pollutants it may be difficult in some 

situations to determine attainment or 

nonattainment of water quality 

standards and set appropriate limits 

because of complex chemical 

interactions which affect the fate and 

ultimate impact of toxic substances in 

the receiving water. In many cases, all 

potentially toxic pollutants cannot be 

identified by chemical methods. In such 

situations, it is more feasible to examine 

the whole effluent toxicity and instream 

impacts using biological methods rather 

than attempt to identify all toxic 

pollutants, determine the effects of each 

pollutant individually, and then attempt 

to assess their collective effect. 

The scientific basis for using 

blological techniques has advanced 

significantly in recent yearn. There is 

now a general consensus that an 

evaluation of effluent toxicity, when 

adequately related to instream 

conditions, can provide a valid 

indication of receiving system impacts. 

This information can be useful in 

developing regulatory requirements to 

protect aquatic life, especially when 

data from toxicity testing are analyied 

in conjunction with chemical and 

ecological data. Generic human health 

effects methods, such as the Ames 

mutagenicity test. and structure-activity 

relationship techniques are showing 

promise and should be used to identify 

potential hazards. However, poliutantspecific techniques are the best way to 

evaluate and control human health 

hazards at this time. 

Biological testing of effluents is an 

important aspect of the water qualitybased approach for controlling toxic 

pollutants. Effluent toxicity data in 

conjunction with other data can be used 

to establish control priorities, assess 

compliance with State water quality 

standards, and set permit limitations to 

achieve those standards. All States have 

water quality standards which include 

narrative statements prohibiting the 

discharge of toxic materials in toxic 

amounts. A few State standards have 

criteria more specific than narrative 

criteria [for example, numerical criteria 

for specific toxic pollutants or a toxicity 

criterion to achieve designated uses). In 

States where numerical criteria are not 

specified, a judgment by the regulatory 

authority is required to set quantitative 

water quality-based limits on chemicals 

and effluent toxicity to assure 
9018 Federal Register 1 Vol. 49, No. 48 1 Friday, March 9, 1984 I Notices 

. __ 

compliance with water qualit> 

standards. 

Note.-Section 308 of the Act trnd 

corresponding State statutes authorizca WA 

and the Stales to require of the owner/ 

operator any information reasonably required 

lo determine permit limits and to determine 

compliance with standards or permit linlik 

Kological methods are specifically 

mentioned. Toxicity permit limits arp 

authorized under Secllon 301 and 4(32 nnrl 

supported by Section 101. 

Application 

This policy applies to EPA and the 

States. The policy addresses the use of 

chemical and biological methods for 

assuring that effluent discharges are 

regulated in accordance with Federal 

and State requirements. This policy was 

prepared. in part, in response to 

concerns raised by litigants to the 

Consolidated Permit Regulations [see FR 

52079, November 18.1982), Use of these 

methods for developing water quality 

standards and trend monitoring are 

discussed elsewhere (see 48 FR 51400. 

November 8,1983 and Basic Water 

Monitoring Program EPA-440/9-76-025). 

This policy is part of EPA’s water 

quality-based control program and does 

not supersede other regulations, policy. 

and guidance regarding use 

attainability, site-specific criteria 

modification, wasteload allocation. and 

water quality management. 

fmplementotion 

Slate Role 

The control of toxic substances to 

protect water quality must be done in 

the context of the Federal-State 

partnership. EPA will work 

cooperatively with the States in 

identifying pbtential water quality 

standards violations. assembling 

relevant data, developing appropriate 

testing requirements. determining 

whether standards are being violated, 

and defining appropriate permit limits. 

No&.-Under sections 303 and 401 of the 

Act. States are given primary responsibility 

for developing water quality standards and 

limits to meet those standards. FPA’R role is 

to review the Stale standards and limits and 

develop revised or additional standards or 

limits as needed to meet the requirements of 

the Act. 

Integration of Approaches 

The type of testing that is most 

appropriate for assessing water quality 

impacts depends on the type of effluent 

and discharge situation. EPA 

recommends that an integrated 

approach, including both biologictll and 

chemical techniques. be used to assess 

and control water quality. The principal 

advantages of chemical-specific 

techniques are that (I) chemical 

analyses are usually less expensive than 

biological measurements in simple 

cases; (21 treatment systems are more 

easily designed to meet chemical 

requirements than’toxicity requirements: 

and (3) human health hazards and 

bioaccumulative pollutants can best be 

addressed at this time by chemicalspecific analysis. The principal 

advantages of biological techniques are 

Ihal (t J the effects of complex 

discharges of many known and 

unknown constituents can be measured 

only by biological analyses; (21 

bioavailability of pollutants after 

discharge is best measured by toxicity 

testing: and (3) pollutants for which 

there are inadequate chemical analytical 

methods or criteria can be addressed. 

Pollutant-specific chemical analysis 

techniques should be used where 

discharges contain few, well-quantified 

pollutants and the interactions and 

effects of the pollutants are known. In 

addition, pollutant-specific techniques 

should be used where health hazards 

are a concern or bioaccumulation is 

suspected. Biological techniques should 

be used where effluents are complex or 

where the combined effects of multiple 

discharges are of concern. EPA 

recognizes that in many cases both 

types of analysis must be used. 

Testing Requirements 

Requirements for dischargers* to 

collect information to assess attainment 

or nonattainment of State water quality 

standards will be imposed only in 

selected cases where the potential for 

nonattainment of water quality 

standards exists. Where water quality 

problems are suspected but there is a 

strong indication that complying with 

BCT/BAT will sufficiently mitigate the 

impacts. EPA recommends that 

applicable permits include testing 

requirements effective after BCT/BAT 

compliance and reopener clauses 

allowing reevaluation of the discharge. The chemical, physical, and biological 

testing to be conducted by individual 

dischargers should be determined on a 

case-by-case basis. In making this 

determination, many factors must be 

considered, including the degree of 

impact. the complexity and variability of 

the discharge, the water body type and 

hydrology, the potential for human 

health impact. the amount of existing 

data, the level of certainty desired in the 

water qualily assessment, other sources 

of pollutants, and the ecology of the 

receiving water. The specific data 

needed to measure the effect that a 

discharger has on the receiving water 

will vary according to these and other 

factors. 

82-3 

An assessment of water quality 

should, to the extent practicable, include 

other point and nonpoint sources of 

pollutants if the sources may be 

contributing to the impacts. Special 

attention should be focused on Publicly 

Owned Treatment Works (POTW’s) 

with a significant contribution of 

industrial waste-water. Recent studies 

have indicated that such POTW’s are cJftel1 SignifiCank SOUrCeS Of bXiC 

materials. When developing monitoring 

requirements. interpreting data, and 

determining limitations. permit 

engineers should work closely with 

water quality staff at both the State and 

Federal Irvels. 

A discharger may be required to 

provide data upon request under section 

308 of the Act, or such a requirement 

may be included in its NPDES permit. 

The development of a final assessment 

may require several iterations of data 

collection. Where potential problems are 

identified, EPA or the State may require 

monitoring to determine whether more 

information is needed concerning water. 

quality effects. 

Use of Data 

Chemical, physIcal. and biological 

data will be used to determine whether, 

after compliance with BCT/BAT 

requirements. there will be violations of 

State water quality standards resulting 

from the discharge(s). The narrative 

prohibition of toxic materials in toxic 

amounts contained in all State 

standards is the basis for this 

determination taking into account the 

designated use for the receiving water. 

For example. discharges to waters 

classified for propagation of cold water 

fish should be evaluated in relation to 

acute and chronic effects on cold water 

organisms. potential spawning areas, 

and effluent dispersion. 

Setting Permit Limikions 

Where violations of water quality 

standards exist or are projected, the 

State and EPA will determine pollution 

control requirements that will attain the 

receiving water designated use. Where 

effluent toxicily is an appropriate 

control parameter, permit limits on 

effluent toxicity should be developed. 4 

such cases, EPA may also iequire a 

permittee to conduct a toxicity reduction 

evaluation. A toxicity reduction 

evaluation is an investigation conducted 

within a plant or municipal system to 

isolate the sources of effluent toxicity, 

specific causative pollutants if possible, 

and determine the effectiveness of 

pollution control options in reducing the 

effluent toxicity. If specific chemicals 

are identified as the cause of the water 
F&al Register / Vol. 49, No. 49 :/ Friday, March 9, 1984 } Notices 

- 

9019 

quality standards violaliori. these 

individual poWants should be limited. 

If a toxicity reduction evaluation 

demonstrates that limiting ap indicator 

parameter will ensure attainment of the 

water quality-based effluent toxicity 

requirement. limits on the indicator 

parameter should be considered in lieu 

of limits on effluent toxicity. Such 

indicator limits are not limits on 

causative pollutants but limits 

demonstrated to result in a specific 

toxicity reduction. 

Monitoring 

Where pollution control requirements 

are expressed in terms of a chemical or 

toxicological piirameter, compliance 

monitoring must include monitoring for 

that parameter. If an indicator 

parameter is used based on the results 

of a toxicity reduction evaluation, 

periodic toxicity testing may be required 

to confirm the adequacy of the indicator. 

Where biological data were used to 

develop a water quality assessment or 

where the potential for water quality 

standards violations exist. biological 

monitoring (including instream 

monitoring) may be required to ensure 

continuing compliance with water 

quality standards. 

EPA believes that the intelligent 

application of an integrated strategy 

using both biological and chemical 

techniques for water quality assessment 

will facilitate the development of 

appropriate controls and the attainment 

of water quality standards. W’A looks 

forward IO working with the States in a 

spirit of cooperation lo further refine 

these techniques. 

Policy sipned February 3. 1984 by jack E. 

Ravan. As&ant administrator for Water. 

Dated: Febrwry 16. 1%. 

jack E. Raven. 

As~r’stonf .4hm,nisfmtcrfor Litter 

IFII 0~ M-twS Fllkd 3-844 1.45 ,ml 

lll.UYG CODE sso4o-Y 

B-24 
APPENDIX B-3 

REGULATIONS FOR TOXICS CONTROL 
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

AUG 21 I989 OFFICE OF 

WATER 

MEMORANDUM 

SUBJECT: New Regulations Governing Water Quality-Based 

Permitting in the NPDES Permitting Pro

FROM: James R. Elder, Director 

of Water Enforcement 

TO: Water Management Division Directors 

Regions I - X 

On May 26, 1989 the Deputy Administrator signed regulations that implement section 304(1) of the CWA. The regulations became 

effective upon his signature and were published in the Federal 

Register on June 2, 1989 (54 Fed. Req. 23868). This rulemaking also clarified and reinforced EPA's existing regulations governing water quality-based permitting. The purpose of this 

memorandum is to describe the significance of these 

clarifications to EPA's baseline water quality-based permitting regulations. 

CHANGES TO 40 C.F.R. PART 122 

Section 122.44 covers the establishment of limitations, 

standards, and other permit conditions in NPDES permits. Subsection (d) covers water quality standards and state 

requirements. Prior to the promulgation of these new regulations the subsection was non-specific, requiring only that NPDES 

permits be issued with requirements more stringent than 

promulgated effluent guidelines as necessary to achieve water 

quality standards. We have strengthened considerably the 

requirements of §122.44(d). The new language is very specific 

and requires water quality-based permit limits for specific toxicants and whole effluent toxicity where necessary to achieve 

state water quality standards. The following is a section-bysection description of the new requirements. 

B-3-1 
2 

1. $122.44(d)(l)(i) 

This new paragraph provides that all pollutants that cause, 

have the reasonable potential to cause, or contribute to an 

excursion above a water quality standard must be controlled to 

achieve all applicable water quality standards, including narrative water quality criteria. We added this paragraph so 

that our regulations would reflect EPA's approach to water 

quality-based permitting. 

2. $122.44(d)(l)(ii) 

Subparagraph (ii) of the new regulations requires the states 

to use valid procedures to determine whether a discharge causes, 

has the reasonable potential to cause, or contributes to an 

excursion above a water quality standard. These procedures must 

account for existing controls on point and nonpoint sources of 

pollution, the variability of the pollutant in the effluent, the 

sensitivity of the test species (when evaluating whole effluent 

toxicity), and where allowed by state water quality standards, 

the dilution of the effluent in the receiving water. The purpose of this new regulation is to require the states to use 

technically valid procedures when determining whether a discharge is exceeding a numeric or narrative water quality criterion. 

When the permitting authority determines, using these procedures, that a discharge causes, has the reasonable potential to cause, 

or contributes to an excursion above a water quality criterion, 

that permit must include one or more water quality-based effluent 

limits established under subparagraphs (iii) - (vi). Subparagraphs (iii) and (iv) deal with water quality-based 

limitations where the state has numeric water quality criteria: 

subparagraphs (v) and (vi) deal with a state's narrative water 

quaity criteria. 

3. $122.44(d)(l)(iii) 

This paragraph requires NPDES permits to include effluent 

limitations for every individual pollutant that causes, has the 

reasonable potential to cause, or contributes to an excursion 

above a numeric water quality criterion. Thus, when a state has 

adopted a water quality criterion for an individual pollutant and 

the state determines under subparagraph (ii) that an effluent 

limit is necessary, subparagraph (iii) requires an effluent limit 

for that individual pollutant. 

4. 3122.44(d)(l)(iv) 

Subparagraph (iv) requires effluent limitations on whole 

effluent toxicity when a discharge is exceeding a state numeric 

criteria for whole effluent toxicity. This paragraph is applied 

B-3-2 
where a state has adopted a numeric criterion for whole effluent 

toxicity (e.g. a discharge must achieve an LC50 of 50% or 

higher). 

5. $122.44(d)(l)(v) 

When the state determines that a discharge exceeds a 

narrative water quality criterion, subparagraph (v) requires effluent limitations on whole effluent toxicity. If, however, 

chemical-specific effluent limitations are demonstrated to be 

sufficient to achieve all applicable water quality standards, 

then subparagraph (v) allows the permitting authority to forego a 

limitation on whole effluent toxicity. It may be necessary for 

you to work with an individual state to ensure that they have the 

necessary protocols to support whole effluent toxicity limits. 

6. $122.44(d)(l)(vi) 

Where an actual or projected excursion above a narrative 

water quality criterion is attributable to a particular 

pollutant, but the state has not adopted a water quality 

criterion for the pollutant of concern, this new regulation requires water quality-based effluent limitations which will 

control the pollutant of concern. Subparagraph (vi) establishes 

three options for developing such limitations. Under these 

options, a state may: 1) calculate a numeric criterion for the 

pollutant: 2) use EPA's water quality criterion for the pollutant of concern; or 3) establish effluent limits on an indicator 

parameter. 

By an indicator parameter we mean a pollutant or pollutant 

parameter for which control of this indicator will result in 

control of the pollutant of concern. For example, it may be 

shown that a more stringent control on total suspended solids will reduce discharge of a metal to a level which achieves the 

water quality standard. Subparagraph (vi) also sets out four 

provisions which must be met to allow the use of an indicator: 

1) The permit must identify which pollutants are intended 

to be controlled by a limit on the indicator parameter. 

2) The fact sheet must set forth the basis for the limit, 

including a finding that compliance with the limit will 

result in controls on the pollutant of concern that are 

sufficient to achieve the water quality standard. 

3) The permit must require all monitoring necessary to 

show continued compliance with water quality standards. 

0-3-3 
4 - 

4) The permit must contain a reopener clause allowing for 

changes in the permit as needed to achieve water 

quality standards. 

A state's narrative water quality criterion serves as the legal basis for establishing such effluent limits. 

7. #122.44(d)(l)(vii) 

Subparagraph (vii) requires that all water quality-based effluent limitations adhere to two fundamental principles: 1) the 

effluent limitations must be derived from and comply with all 

applicable water quality standards: and 2) the effluent 

limitations are consistent with the assumptions and requirements of an applicable wasteload allocation (WLA) if a WLA is available 

for the pollutant. 

CHANGES TO 40 C.F.R. PART 123 

We amended the permit objection regulations at 40 C.F.R. 

$123.44 to reflect the amendments to $122.44(d)(l). Under 

$123.44(c)(8) EPA may now object to a state-issued permit if the 

permit does not meet the requirements of $122.44(d)(l). Thus, if 

a state does not use technically sound procedures for evaluating the need for water quality-based effluent limitations then EPA 

may object to the permit. Also, if a state fails to include 

chemical-specific or whole effluent toxicity limitations in a 

permit as required by paragraphs (iii) - (vi), then EPA may object to the permit. Finally, if a water quality based effluent 

limitation is not derived according to the principles in 

subparagraph (vii) then EPA may object to the permit. 

If a state's surface water toxics control program is not 

adequate to implement these requirements, the new regulations at 

40 C.F.R. $123.63 expand EPA's criteria for withdrawing a state's 

NPDES program. Under the new regulations ($123.63(a)(S)), EPA 

may withdraw a state's NPDES program if the state fails to 

develop an adequate regulatory program for developing water 

quality-based effluent limitations. In November 1987, 

Headquarters provided procedural and technical guidance to the 

Regions on conducting state toxic8 control program reviews to 

assess the adequacy of state water quality-based control 

programs. This guidance sets guidelines for assessing whether or 

not a state's regulations, policies, and technical guidance constitute an adequate program. 

The significance of these additions to Part 123 is twofold. 

First, the Regions must issue permits which comply with these 

requirements and must work with the NPDES states to insure they 

also issue permits which comply with these regulations. If the 

states do not issue permits consistent with Part 123, the Region 

must veto insufficient permits and work with the states to 

B-34 
reissue the permits with water quality-based effluent limitations 

which achieve water quality standards. The specific requirements 

in $122.44(d) are structured in a way that implements EPA's 

Policy for the Development of Water Quality-Based Permit 

Limitations for Toxic Pollutants (49 Fed. Req. 9016 March 9, 

1984). Second, Regions will need to look closely at each state's 

surface water toxics control program to ensure that the state's 

regulations, policies and technical guidance result in the 

consistent and comprehensive development of NPDES permits which 

achieve the state's water quality standards. Where this does not 

occur, each Region should work with the state to rectify the 

problem and, after these negotiations and where necessary, 

investigate the possibility of withdrawing the NPDES program. 

I hope these regulations will assist you in developing water 

quality-based effluent limits and will support your efforts to 

implement surface water toxic8 control programs. If you have 

questions or need more information about these requirements, 

please contact Cynthia Dougherty at FTS 475-9545 or have your 

staff contact Rick Brandes at FTS 475-9537. 

cc: Permits Branch Chiefs, Regions I - X 

Martha Prothro, OWRS 

B-3-5 
23868 Federal Register / Vol. 54, No. 105 / Friday, June 2, 1989 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

[FRL-35574 

40 CFR plrtr 122,123 d 130 

Nstlonal Pollutant Dkchrr@ 

Ellminatlon System; Sum Wdar 

Toxic8 Control Program 

AOENCY: JZnviranmentaI Protection 

Agency. 

ACTION Final Rule. 

and Standards, (WH-553), U.S. 

Environmental Protection Agency, 4.01 M 

Street SW., Washington, DC 2OM0, (202) 

382-7056. The Public record for this 

regulation ie available at the EPA 

library, M~~KM, U.S. Environmental 

Protection Agency, 401 M Street SW., 

Washington, DC 20480. 

SUMMARY: Today’s action amends Parts 

122,123. and 130 of EPA’s regulations. 

The regulations clarify EPA’s surface 

water toxica control program, and 

incorporate section 308(a) of the Water 

Quality Act of 1987 into EPA’s toxics 

control program. Section 308[a) of the 

Water Quality Act added section 304(l) 

to the Clean Water Act [hereafter 

referred to as section 304(l)). Section 

304(l) requires the states to identify 

those waters that are adversely affected 

by toxic, conventional, and 

nonconventional pollutants, and 

requires the states to prepare individual 

control strategies that will control point 

source discharges of toxic pollutants. 

The states must submit lists of waters 

and individual control strategies to EPA 

for review, and if EPA disapproves a 

state’s decision with respect to a list or 

an individual control strategy, then EPA 

must implement the requirements of 

section 304(l) in cooperation with the 

state. EPA and the states must 

accomplish the tasks in section 304(l) 

according to an ambitious series of 

deadlines. Today’s regulations will 

strengthen State and Federal controls 

over discharges to toxic pollutants, and 

will assist EPA and the states in 

satisfying the requirements of section 

304(l) of the CWA. 

EFFECTIVE DATE These regulations shall 

be effective on May 243,1989 at 1:fXl p.m. 

Eastern Daylight Savings Time. In 

accordance with 40 CFR 23.2, EPA 

hereby specifies that these regulations 

shall be considered final agency action 

for purposes of judicial review at 1:OO 

p.m. Eastern Daylight Savings Time on 

May 26.1989. 

FOR FURTHER INFOAYATION COWACE 

Paul Connor, Program Development 

Branch, Office of Water Enforcement 

and Permits, @N-338), US. 

Environmental Protection Agency, 401 M 

Street, SW., Washington, DC 20480, 

(202) 475-9537, or Judith Leckrone. 

Assessment and Watershed Protection 

Division, Office of Water Regulations 

B-3-6 
Faded RQW- / Vol. 5% No. 106 / Friday, June Z,~SSS / Rules and Reguiatiorm 2x95 

PART In--EPA ADMINISTERED 

Pf%MlT PfWGRAMS THE NATIONAL 

1. The authority citation for Part 122 

continuer to read au follows: 

AutbaitY: Tba Clean Water Act. 33 USC. 

1251 et req. 

2. Section 1222 is amended by adding 

inunw~betical order a new definition aa . 

om.2 D@fhhma l l l l t 

Whole effruent toxicity mean0 the 

aggregate toxk effect of an effluent 

measured directly by a toxicity test. 

3. Paragraph [d)(l) of 0 IZZ.M is 

revised to read as follows: 

8w2U Ed@bkhgIlmltr(knr, 

rtmdudr,~-P.mlto#lditkn 

~ww&--msproomy8e. 

. l l . l 

(4 . l . 

(11 Achieve wrter quality standards 

established under rection 303 of the 

CWA including State narrative criteria 

for water qualitv. . 

(I) Limitition~ must control all 

pollutants or pollutant parameters 

(either conventional. nonconventional 

or toxic pollutants) which the Director’ 

determines are or may be discharged at 

a level which will cause, have the 

reasonable potential to catrae. or 

contribute to an excursion above any 

State water quality standard, including State narrative criteria for water qualtty. (ii) When determining whether a 

discharge causes, has the reasonable 

potential to cause, or contributes to an 

in-&ream excursion above a narrative or 

numeric criterie within a State water 

quality standard. the permitting 

authority shell use procedures which 

account for existing controle on point 

and nonpoint sources of pollution, the 

variability of the pollutant or pollutant 

parameter in the effluent, the Beneitivity 

of the species to toxicity testing (when 

evaluating whole effluent toxicity), and 

where appropriate, the dilution of the 

effluent in the receiving water. 

(iii) When tbe permitttng authority 

determines, uain~ the procedures in 

paragraph (d)(l)(ii) of this section. thst a 

discharge causes, hae the reasonable 

potential to cause, or contributes to an 

in&ream excursion above the allowable 

ambient concentration of a State 

numeric criteria witbin a State water 

quality standard for an individual 

pollutant, the permit must contain 

effluent limits for that pollutant. (iv) When the permitting authority 

determines; wingt the prodedurea in 

paregraph (d)(l)(ii) of this section, that a 

discharge causea, haa the reasonable 

potential to cause, or contributes to an 

in-dream excursion above the numeric 

criterion for whole effluent toxicity, the 

permit must contain effluent limit8 for 

whole effluent toxicity. Iv1 ¢ aa Drovided in thie 

rubpamgr~ph, Ghen the permitting 

authority deterrntnea, using the 

procedurea in paragraph (d)(l)(ii) of this 

recttoa toxicity testing data, or other 

information, tbat a discharge causes, has 

the reasonable potential to catme, or 

contributes to an in&ream excursion 

above a narrative criterion within an 

applicable State water quality standard, 

the permit must contain effluent hmita 

for whole effluent toxicity. Limits on 

whole effluent toxicity are not necessary 

where tbe permitting authority demonstrates in the fact sheet or 

statement of basis of the NPDES permit, 

using the procedure8 in paragraph 

(d)(l)@) of this section, that chemicalspecific limita for the effluent are 

sufficient to attain and maintain 

applicable numeric and narrative State 

water quality etandarda. 

(vi) Where a State has not established 

a water quality criterion for a specific 

chemical pollutant that ia present in an 

effluent at a concentretton that cnuae8, 

has the reaeonable potential to catme, or 

contributes to an excursion above a 

narrative criterion within an applicable 

State water quality standard, the 

0-3-7 

permitting authority muat establish 

effluent hmits ueing one or more of the 

following optione: 

(A) Establteh effluent limita ustng a 

calculated numeric water quality 

criterion for the pollutant which the 

permitting authority demonstrates will 

attain and maintain applicable narrative 

water quality criteria and will fully 

protect the designated use. Such a 

criterion may be derived wing a 

proposed State criterion, or an explicit 

State policy or regulation interpreting its 

narrative water quality criterion, 

supplemented with other relevant 

information which may include: EPA’s 

Water Quality Standards Handbook, 

October ‘166% risk assessment data, 

exposure data, information about the 

pollutant from the Food and Drug 

Administration, and current EPA criteria 

documents; or 

(B) Establish effluent limits on a caaeby-case basis, using EPA’s water quality 

criteria, published under section m(a) 

of the CWA, supplemented where 

necessary by other relevant information; 

or 

(C) Establish effluent limitatione on an 

indicator parameter for the pollutant of 

concern, provided: (1) Tbe permit identifies which 

pollutanta are intended to be controlled 

by the use of the effluent limitation; 

(2) The fact sheet required by P 1~~6 

sets forth the basis for the limit, 

including a finding that compliance with 

the effluent limit on the indicator 

parameter will result in controls on the 

pollutant of concern which are sufficient 

to attain and maintain applicable water 

quality standards; 

(3) The permit requires ill effluent and 

ambient monitoring necessary to show 

that during the term of the permit the 

limit on the indicator parameter 

continuea to attain and maintain 

applicable water quality standards; and 

(4) The permit contains a reopener 

clause allowing tbe permitting authority 

to modify or revoke and reissue the 

Permit if the limit8 on the indicator 

parameter no longer attain and maintain 

applicable water quality standards. 

(vii) When developing water qualitybased effluent limits under this 

EEqh$e permitting authority shall 

(A) The level of water quality to be 

achieved by limite on point sources 

established under this paragraph ie 

derived from, and complies with all 

applicable water quality standards; and 

(B) Effluent bmtte developed to 

protect a narrative water quality 

criterion, a numeric water quality 

criterion, or both, ere consistent with the 

aesumptiona and requirements of any 

available wasteload allocation for the 
Feded Register / Vol. 64, No. 105 / Friday, June 2. 1989 / Rules and Regulations 

discharge prepared by the Stete and 

approved by EPA pursuant to 40 CFR 

130.7. 

. l . . l 

4. The title of paragraph (eB] of 8 12244 

is revised to read as follows: 

. t . . . 

(e) Technology-based controls for 

toxic pollutants. l l l 

PART 123-STAlE PROORAM 

REOWREYENTS 

1. The authority citation for Part 123 

continues to read aa follows: 

Authority: Clean Water Act, 33 U.S.C. 1251 

et seq. 

2. Section 123.4 ie amended by 

adding paregraph [C)(S) to read as 

follows: 

0122.44 EPAmfhwofmldoqecthsto 

stat. pBmtl8. l + . . l 

# ;ha kffluent limits of a permit fail 

to satisfy the requirement8 of 40 CFR 

122.&(d). 

. . . t l 

3. In 0 123.46 paragraph (a) is revised 

and paragraphs (cl, (d). (e) and (fj are 

added. as follows: 

0 122A6 IndlvmJsl clbbor 8tratoglaa 

(a) Not later than February 4,1989. 

each State shall submit to the Regional Administrator for review, approval, and 

implementation an individual control 

strategy for each point source identified 

by the State pursuant to section 

304(1)(1)(C) of the Act which will 

produce a reduction in the dkharge of 

toxic pollutants from the point source8 

identified under section 304(l)(l)(C) 

through the establishment of effluent 

limi ta tione under section 402 of the 

CWA and water quality standards 

under section 303(c)(2)(B) of the CWA, 

which reduction is sufficient, in 

combination with existing controla on 

point and nonpoint sources of pollution, 

to achieve the applicable water quality 

standard as soon as possible. but not 

later than three years after the date of 

the establishment of such strategy. l l . . . 

(cl For the purposes of this section the 

term individual control strategy, as set 

forth in section 304(l) of the CWA. 

means a final NPDES permit with 

supporting document& on showing that 

effluent limits acs consistent with an 

approved wasteload allocatfon, or other 

documentation which shows that 

applicable water quality standards wlll 

be met not later than three years after 

the individual control strategy ia 

established. Where a State is unable to 

issue a final permit on or before 

Febmary ~,ISICI, au individual kntrol 

strategy may be a draft per&t with an 

attached schedule (provided the State 

meets the schedule for iesu@ the final 

permit) irdlcating that the permit will be 

issued on or before February 4.1990. If a 

point source is eubject to section 

304(I)(l)(C) of the CWA and is also 

subject to an on-eite response action 

under section8 101 or 108 of the 

Comprehensive Environmental 

Re8pon8e. Compensation, and Liability 

Act of 1980 (CERCLA), (42 U.S.C. 8801 et 

seq.), an individual control strategy may 

be the decision document (which 

incorporates the applicable or relevant 

and appropriate requirements under the 

CWA) prepared under sections 104 or 

106 of CERCLA to addree8 the release or 

threatened release of hazardow 

substances to the environment. 

(d] A petition submitted pursuant to 

section 304(l)(3) of the CWA must be 

submitted to the appropriate Regional 

AdminMrator. Petitions must identify a 

waterbody in sufficient detail so that 

EPA is able to determine the location 

and boundaries of the waterbody. The 

petition must also identify the list or 

lists for which the waterbody qualifiis. 

and the petition must explain why the 

waterbody satisfies the criteria for 

listing under CWA section X&%(l) and 40 

CFR 13mO(d)(8). 

(e) If the Regional Administrator 

disapproves one or more individual 

control strategies, or if e State fails to 

provide edequate public notice and an 

opportunity to comment on the ICSs. 

then, not later than June 4.lseS. the 

Regional Administrator shall give a 

notice of approval or disapproval of the 

individual control strategies submitted 

by each State pursuant to this section es 

follows: 

(11 The notice of approval or 

dlsapproval given under this paragraph 

shall include the following: 

(i) The name and address of the EPA 

office that reviews the State’8 

submittals. 

(ii) A brief description of the section 

304(l) process. 

(Iii) A list of ICSs disapproved under 

this section and a finding that the ICES 

will not meet all applicable review 

criteria under this section and section 

304(l) of tha CWA. 

(iv) If the Regional Administrator 

determines that a State did not provide 

adequate pubklc notice and an 

opportunity to cqmment on the waters, 

point m or ICSs prepared pursuant 

to section 304(I). or if the Regional 

Administrator choosea to exercise his or 

her discr8tioa a lbt of the ICS8 

approved under this section, and a 

B-3-8 

5nding that the ICSs satisfy all 

applicable review rsiteria. 

iv) The location where interested 

per---y -8 WA’S RCOrdS Of 

approval end disepprvvaL 

(vi) The name. address, and telephone 

number of the person at the Regional Office from whom interested persons 

may obtain more informaff on. 

(vii) Notice that written petitions or 

comments are due within 120 days. 

(2) The Regional Administrator shall 

provide the notice of approval or 

disapproval given under this paragraph 

to the eppropriate State Director. The 

Regional Administrator ahalI publish a 

notice of availability, ln a daily or 

weekly newspaper with State-wide 

circulation or In the Fetied Register, for 

the no&e of approval or disapproval. 

The Regional Administrator shall also 

provide written notice to each 

discharger identified under section 

304(1)(1)(C), that EPA has listed the 

discharger under section 3w(l)(l](C). 

(3) A8 soon a8 practicable but not 

later than June 4.lSaa the Regional 

Offices shall issue a response to 

pet&ions or comments received under 

section 304(f). The response to 

comments shall be given in the same 

manner as the notice described in 

paragraph (e) of this section except for 

the following changes: 

(i) The liata of ICSs reflecting any 

changes made pursuant to comments or 

petitions received. 

(ii) A brief description of tbe 

subsequent steps in the section ~~(11 

process. 

(fj EPA 8haIl review, and approve or 

disapprove, the individual control 

strategies prepared under section 304(l) 

of the CWA, using the applicable 

criteria set forth in saction 304(l) of the 

CWA, and in 40 CFR Part 122, including 

P 12214(d). At any time after the 

Regional Administrator disapproves an 

ICS (or conditionally aproves a draft 

permit as an ES). the Regional Office 

may submit a written notification to the 

State that the Regional Office intends to 

issue the KS. Upon mailing the 

notification, and notwithstanding any 

other reguIation. exclusive authority to 

issue the permit passes to EPA. 

4. Section 123.63 is amended by 

eddlng paragraph (a)(5) to read as 

followa: 

(a) ’ l l 

(51 Where the State fail8 to develop an 

adequate regulatory program for 

developing watsr qua&y-based effluent 

lmts in NPDEspermit8. 
APPENDIX B-4 

WHOLE EFFLUENT TOXICITY PERMITTING PRINCIPLES 

AND ENFORCEMENT STRATEGY 
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON. D.C. 20460 

January 25, 1989 

OFFICE OF 

WATER 

MEMORANDUM 

SUBJECT: 

Enforcement Strategy 

Whole Effluent Toxicity Basic Permitting Principles and 

FROM: Rebecca W. Hanmer, Acting Assistant Administrator 

Office of Water 

TO: Regional Administrators 

Since the issuance of the "Policy for the Development of 

Water Quality-based Permit Limitations for Toxic Pollutants" in 

March of 1984, the Agency has been moving forward to provide 

technical documentation to support the integrated approach of 

using both chemical and biological methods to ensure the 

protection of water quality. The Technical Support Document for 

Water Quality-based Toxics Control [September, 1985) and the 

Permit Writer's Guide to Water Quality-based Permitting for Toxic 

Pollutants (July, 1987) have been instrumental in the initial 

implementation of the Policy. The Policy and supporting 

documents, however, did not result in consistent approaches to 

permitting and enforcement of toxicity controls nationally. When 

the 1984 Policy was issued, the Agency did not have a great deal 

of experience in the use of whole effluent toxicity limitations 

and testing to ensure protection of water quality. We now have 

more than four years of experience and are ready to effectively 

use this experience in order to improve national consistency in 

permitting and enforcement. 

In order to increase consistency in water quality-based 

toxicity permitting, I am issuing the attached Basic Permitting 

Principles for Whole Effluent Toxicity (Attachment 1) as a 

standard with which water quality-based permits should conform. 

A Workgroup of Regional and State permitting, enforcement, and 

legal representatives developed these minimum acceptable 

requirements for toxicity permitting based upon national 

experience. These principles are consistent with the toxics 

control approach addressed in the proposed Section 304(1) 

regulation. Regions should use these principles when reviewing 

draft State permits. If the final Section 304(1) regulations 

include changes in this area, we will update these principles as 

necessary. Expanded guidance on the use of these principles will 

be sent out shortly by James Elder, Director of the Office Of 

B-4-1 
-2- 

Water Enforcement and Permits. This expanded guidance will 

include sample permit language and permitting/enforcement scenarios. 

Concurrent with this issuance of the Basic Permitting Principles, I am issuing the Compliance Monitoring and 

Enforcement Strategy for Toxics Control (Attachment 2). This 

Strategy was developed by a Workgroup of Regional and State 

enforcement representatives and has undergone an extensive 

comment period. The Strategy presents the Agency's position on 

the integration of toxicity control into the existing National 

Pollutant Discharge Elimination System (NPDES) compliance and 

enforcement program. It delineates the responsibilities of the 

permitted community and the regulatory authority. The Strategy describes our current efforts in compliance tracking and quality 

assurance of self-monitoring data from the permittees. It 

defines criteria for review and reporting of toxicity violations 

and describes the types of enforcement options available for the 

resolution of permit violations. 

In order to assist you in the management of whole effluent 

toxicity permitting, the items discussed above will join the 1984 

Policy as Appendices to the revised Technical Support Document 

for Water Quality-based Toxics Control. To summarize, these 

materials are the Basic Permitting Principles, sample permit 

language, the concepts illustrated through the permitting and 

enforcement scenarios, and the Enforcement Strategy. I hope 

these additions will provide the needed framework to integrate the control of toxicity into the overall NPDES permitting 

program. 

I encourage you and your staff to discuss these documents 

and the 1984 Policy with your States to further their efforts in 

the implementation of EPA's toxics control initiative. 

If you have any questions on the attached materials, please 

contact James Elder, Director of the Office of Water Enforcement 

and Permits, at (FTS/202) 475-8488. 

Attachments 

cc: ASWIPCA 

Water Management Division Directors 

B-4-2 
EASIC PERMITTING PRINCIPLES FOR WHOLE EFFLUENT TOXICITY 

1. Permits must be protective of water quality. 

a. At a minimum, all major permits and minors of 

concern must be evaluated for potential or known 

toxicity (chronic or acute if more limiting). 

b. Final whole effluent toxicity limits must be 

included in permits where necessary to ensure 

that State Water Quality Standards are met. 

These limits must properly account for effluent 

variability, available dilution, and species 

sensitivity. 

2. Permits must be written to avoid ambiguity and ensure 

enforceability. 

a. Whole effluent toxicity limits must appear in Part I 

of the permit with other effluent limitations. 

b. Permits contain generic re-opener clauses which 

are sufficient to provide permitting authorities 

the means to re-open, modify, or reissue the 

permit where necessary. Re-opener clauses covering 

effluent toxicity will not be included in the 

Special Conditions section of the permit where 

they imply that limit revision will occur based 

on permittee inability to meet the limit. Only 

schedules or other special requirements will be 

added to the permit. 

C. If the permit includes provisions to increase 

monitoring frequency subsequent to a violation, it 

must be clear that the additional tests only determine the continued compliance status with the limit; 

they are not to verify the original test results. 

d. Toxicity testing species and protocols will be 

accurately referenced/cited in the permit. 

3. Where not in compliance with a whole effluent toxicity limit, permittees must be compelled to come into compliance 

with the limit as soon as possible. 

a. Compliance dates must be specified. 

b. Permits can contain requirements for corrective 

actions, such as Toxicity Reduction Evaluations 

(TRW, but corrective actions cannot be delayed 

pending EPA/State approval of a plan for the 

corrective actions, unless State regulations 

require prior approval. Automatic corrective 

actions subsequent to the effective date of a final 

whole-effluent toxicity limit will not be included 

in the permit. 

B-4-3 
ATTACHMENT 1 

Explanation of the Basic Permitting Principles 

The Basic Permitting Principles present the minimum 

acceptable requirements for whole-effluent toxicity permitting. They begin with a statement of the goal of whole-effluent 

toxicity limitations and requirements: the protection of water 

quality as established through State numeric and narrative Water 

Quality Standards. The first principle builds on the Technical 

Support Document procedures and the draft Section 304(l) rule 

requirements for determining potential to violate Water Quality Standards. It requires the same factors be considered in setting whole-effluent toxicity based permits limits as are used to 

determine potential Water Quality Standards violations. It 

defines the universe of permittees that should be evaluated for 

potential violation of Water Quality Stand-ids, L.Ad the,tfore 

possible whole-effluent limits, as all majors and minors of 

concern. 

The second permitting principle provides basic guidelines for avoiding ambiguities that may surface in permits. Wholeeffluent toxicity limits should be listed in Part I of the permit 

and should be derived and expressed in the same manner as any other water quality-based limitations (i.e., Maximum Daily and 

Average Monthly limits as required by Section 122.45(d)). 

In addition, special re-opener clauses are generally not 

necessary, and may mistakenly imply that permits may be re-opened 

to revise whole-effluent limits that are violated. This is not 

to imply that special re-opener clauses are never appropriate. 

They may be appropriate in permits issued to facilities that 

currently have no known potential to violate a Water Quality Standard; in these cases, the permitting authority may wish to 

stress its authority to re-open the permit to add a wholeeffluent limit in the event monitoring detects toxicity. 

Several permittees have mistakenly proposed to conduct 

additional monitoring subsequent to a violation to "verify" their 

results. It is not possible to verify results with a subsequent 

test whether a new sample or a split-sample which has been stored 

(and therefore contains fewer volatiles) is used. For this 

reason, any additional monitoring required in response to a 

violation must be clearly identified as establishing continuing compliance status, not verification of the original violation. 
- 2- 

The second principle also deals with the specification of 

test species and protocol. Clearly setting out the requirements 

for toxicity testing and analysis is best done by accurately referencing EPA's most recent test methods and approved 

equivalent State methods. In this way, requirements which have 

been published can be required in full, and further advances in 

technology and science may be incorporated without lengthy permit revisions. 

The third and final permitting principle reinforces the 

responsibility of the permittee to seek timely compliance with 

the requirements of its NPDES permit. Once corrective actions 

have been identified in a TRE, permittees cannot be allowed to 

delay corrective actions necessary to comply with water quality- based whole effluent toxicity limitations pending Agency review 

and approval of voluminous reports or plans. Any delay on the 

part of the permittee or its contractors/agents is the 

responsibility of the permittee. 

The final principle was written in recognition of the fact 

that a full-blown TRE may not be necessary to return a permittee 

to compliance in all cases, particularly subsequent to an initial 

TRF,. As a permittee gains experience and knowledge of the 

operational influences on toxicity, TREs will become less 

important in the day to day control of toxicity and will only be 

required when necessary on a case-specific basis. 

B-4-5 
ATTACHMENT 2 

to the Cwce Watorba UEniorcm 

StratecnriQlc,hToxicsControl 

The me Modtormnt Strateuv for 

Contrd sets forth the Agency's strategy for tracking compliance with and enforcing whole-effluent toxicity monitoring requirements, limitations, schedules and reporting requirements. 

The Strategy delineates the respective responsibilities of 

permittees and permitting authorities to protect water quality through the control of whole-effluent toxicity. It establishes 

criteria for the review of compliance data and the quarterly reporting of violations to Headquarters and the public. The 

Strategy discusses the integration of whole-effluent toxicity control into our existing.fnspection and quality assurance 

efforts. It provides guidelines on the enforcement of wholeeffluent toxicity reguirements. 

The Strategy also addresses the concern many permittees share as they face the prospect of new requirements in their 

permit - the fear of indiscriminate penalty assessment for 

violations that they are unable to control. The Strategy recognizes enforcement discretion as a means of dealing fairly with permittees that are doing everything feasible to protect water quality. As indicated in the Strategy, this discretion 

deals solely with the assessment of civil penalties, however, and 

is not an alternative to existing procedures for establishing relief from State Water Quality Standards. The Strategy focuses 

on the responsibility of the Agency and authorized States to 

require compliance with Water Quality Standards and thereby 

ensure protection of existing water resources. 

B-4-6 
01/19/89 

COMPLIANCE MONITORING AND ENFORCEMENT STRATEGY 

FOR TOXICS CONTROL 

I. Background 

Issuance of NPDES permits now emphasizes the control of toxic 

pollutants, by integrating technology and water quality-based permit limitations, best management practices for toxic discharges, sludge requirements, and revisions to the pretreatment implementa- tion requirements. These requirements affect all major permittees and those minor permittees whose discharges may contribute to 

impairment of the designated use for the rec'eiving stream. The 

goal of permitting is to eliminate toxicity in receiving waters 

that results from industrial and municipal discharges. 

Major industrial and municipal permits will routinely contain 

water quality-based limits for toxic pollutants and in many cases 

whole effluent toxicity derived from numerical and narrative 

water quality standards. The quality standards to establish NPDBS 

permit limits are discussed in the "Policy for the Development of 

Water Quality-based Permit Limits for Toxic Pollutants," 49FR 9016, 

March 9, 1984. The Technical Support Document for Water Quality- based Toxics Control, EPA X440/44-85032 September, 1985 and the 

.Permit Writer's Guide to Water Quality-Gased Permitting for Toxic 

Pollutants, Office of Water, May, 1987, provide guidance for interpreting numerical and narrative standards and developing permit limits. 

The Water Quality Act (WQA) of 1987 (PL 100-4, February 4, 

1987) further directs EPA and the States to identify waters that 

require controls for toxic pollutants and develop individual 

control strategies including permit limits to achieve control of 

toxics. The WQA established deadlines, for individual control 

strategies (February 4, 1989) and for compliance with the toxic 

control permit requirements (February 4, 1992). This Strategy will support the additional compliance monitoring, tracking, evaluation, and enforcement of the whole effluent toxicity controls 

that will be needed to meet the requirements of the WQA and EPA's 

policy for water quality-based permitting. 

It is the goal of the Strategy to assure compliance with 

permit toxicity limits and conditions through compliance inspec- tions, compliance reviews, and enforcement. Water quality-based 

limits may include both chemical specific and whole effluent toxicity limits. Previous enforcement guidance (e.g., Enforcement 

Management System for the National Pollutant Discharge Elimination 

System, September, 1986: National Guidance for Oversight of NPDES 

Programs, May, 1987: Guidance for Preparation of Quarterly and 

Semi-Annual Noncompliance Reports, March, 1986) has dealt with 

0-4-7 
-2- 

chemical-specific water quality-based limits. This Strategy will 

focus on whole effluent toxicity limits. Such toxicity limits may 

appear in permits, administrative orders, or judicial orders. 

II. Strategy Principles 

This 

1) 

2) 

3) 

4) 

strategy is based on four principles: 

Permittees are responsible for attaining, monitoring, and maintaining permit compliance and for the quality 

of their data. 

Regulators will evaluate self-monitoring data quality 

to ensure program integrity. 

Regulators will assess compliance through inspections, 

audits, discharger data reviews, and other independent monitoring or review activities. 

Regulators will enforce effluent limits and compliance schedules to eliminate toxicity. 

III. Primary Implementation Activities 

In order to implement this Strategy fully, the following activities are being initiated: 

A. Immediate development 

1. The NPDES Compliance Inspection Manual was 

revised in May 1988 to include procedures for 

performing chronic toxicity tests and evaluating toxicity reduction evaluations. An inspector 

training module was also developed in August 

1988 to support inspections for whole effluent 

toxicity. 

2. The Permit Compliance System (the national NPDES 

data base) was modified to allow inclusion 

of toxicity limitations and compliance schedules 

associated with toxicity reduction evaluations. 

The PCS Steering Committee will review standard 

data elements and determine if further modifications are necessary. 

3. Compliance review factors (e.g., Technical 

Review Criteria and significant noncompliance definitions) are being proposed to evaluate 

violations and appropriate response. 

4. A Quality Assurance Fact Sheet has been developed (Attached) to review the quality of toxicity test 

results submitted by permittees. 

04-a 
-3- 

5. The Enforcement Response Guide in the Enforcement 

Management System will be revised to cover the use 

of administrative penalties and other responses to 

violations of toxicity controls in permits. At 

least four types of permit conditions are being examined: (1) whole-effluent toxicity monitoring (sampling and analysis), (2) whole effluent 

toxicity-based permit limits, (3) schedules to 

conduct a TRE and achieve compliance with water 

quality-based limits, and (4) reporting requirments. 

B. Begin development in Spring 1989 

With the assistance of the Office of Enforcement and 

Compliance Monitoring (OECM), special remedies and model forms 

will be developed to address violations of toxicity permit limits (i.e., model consent decrees, model complaints, revised 

penalty policy, model litigation reports, etc.) 

IV. Scope and Implementation of Strategy 

A. Compliance Tracking and Review 

1. Compliance Tracking 

The Permits Compliance System (PCS) will be 

used as the primary system for tracking limits and 

monitoring compliance with the conditions in NPDES 

permits. Many new codes for toxicity testing have 

already been entered into PCS. During FY 89, headquarters will provide additional guidance to Regions and States on PCS coding to update existing documentation. The Water Enforcement Data Base (WENDB) 

requirements as described in the PCS Policy Statement 

already require States and Regions to begin incorporating toxicity limits and monitoring information 

into PCS. 

In addition to guidance on the use of PCS, 

Headquarters has prepared guidance in the form 

of Basic Permitting Principles for Regions and 

States that will provide greater uniformity nationally on approaches to toxicity permitting. One of the major problems in the tracking and 

enforcement of toxicity limits is that they differ 

greatly from State-to-State and Region-to-Region. The Permits Division and Enforcement Division in 

cooperation with the PCS Steering Committee will 

establish standard codes for permit limits and 

procedures for reporting toxicity results based on 

this guidance. 

B-4-9 
-4- 

Whole effluent toxicity self-monitoring data 

should undergo an appropriate quality review. (See attached checklist for suggested toxicity review 

factors.) All violations of permit limits for 

toxics control should be reviewed by a professional qualified to assess the noncompliance. Regions and 

States should designate appropriate staff. 

2. Compliance Review 

Any violation of a whole effluent toxicity limit is of concern to the regulatory agency and 

should receive an immediate professional review. 

In terms of the Enforcement Management System (EMS), 

any whole effluent violation will have a violation 

review action criterion (WAC) of 1.0. However, the 

appropriate initial enforcement response may be to 

require additional monitoring and then rapidly escalate the response to formal enforcement if the 

noncompliance persists. Where whole effluent 

toxicity is based on a pass-fail permit limitation, 

any failure should be immediately targeted for 

compliance inspection. In some instances, assessment 

of the compliance status will be required through issuance of Section 308 letters and 309(a) orders to 

require further toxicity testing. 

Monitoring data which is submitted to fulfill 

a toxicity monitoring requirement in permits that do 

not contain an independently enforceable whole-effluent 

toxicity limitation should also receive immediate 

professional review. 

The burden for testing and biomonitoring is on 

the permittee; however, in some instances, Regions and 

States may choose to respond to violations through sampling or performance audit inspections. When an 

inspection conducted in response to a violation identifies noncompliance, the Region or State should 

initiate a formal enforcement action with a compliance schedule, unless remedial action is already required 

in the permit. 

B. Inspections 

EPA/State compliance inspections of all major permittees 

on an annual basis will be maintained. For all facilities 

with water quality-based toxic limits, such inspections should 

include an appropriate toxic component (numerical and/or 

whole effluent review). Overall the NPDES inspection and 

data quality activities for toxics control should receive 

greater emphasis than in the present inspection strategy. 

B-4-10 
-5- 

1. Regional/State Capability 

The EPA’s "Policy for the Development of Water 

Quality-based Permit Limits for Toxic Pollutants" 

(March 9, 1984 Federal Register) states that EPA 

Regional Administrators will assure that each 

Region has the full capability to conduct water 

quality assessments using both biological and chemical methods and provide technical assistance to the 

States. Such capability should also be maintained 

for compliance biomonitoring inspections and toxics 

sampling inspections. This capability should include 

both inspection and laboratory capability. 

2. Use of Nonsampling Inspections 

Nonsampling inspections as either compliance 

evaluations (CEIs) or performance audits (PAIs) can 

be used to assess permittee self-monitoring data 

involving whole effluent toxicity limits, TREs, and 

for prioritization of sampling inspections.* As 

resources permit, PAIs should be Used to verify biomonitoring capabilities of permittees and 

contractors that provide toxicity testing selfmonitoring data. 

3. Quality Assurance 

All States are encouraged to develop the 

capability for acute and chronic toxicity tests 

with at least one fish and one invertebrate species for freshwater and saltwater if appropriate. NPDES 

States should develop the full capability to assess 

compliance with the permit conditions they establish. 

EPA and NPDES States will assess permittee 

data quality and require that permittees develop 

quality assurance plans. Quality assurance plans 

must be available for examination. The plan should 

include methods and procedures for toxicity testing and chemical analysis: collection, culture, maintenance, and disease control procedures for test 

organisms; and quality assurance practices. The 

* Due to resource considerations, it is expected that sampling 

inspections will be limited to Regional/State priorities in 

enforcement and permitting. Routine use of CEIs and PAIs should 

provide the required coverage. 

B-4-11 
-6- 

permittee should also have available quality control 

charts, calibration records, raw test data, and 

culture records. 

In conjunction with the QA plans, EPA will 

evaluate permittee laboratory performance on EPA 

and/or State approved methods. This evaluation is 

an essential part of the laboratory audit process. EPA will rely on inspections and other quality 

assurance measures to maintain data quality. However, 

States may prefer to implement a laboratory certification program consistent with their regulatory authorities. Predetermined limits of data acceptability will need to be established for each test 

condition (acute/chronic), species-by-species. 

c. Toxicity Reduction Evaluations (TREs) 

TREs are systematic investigations required of permittees which combine whole effluent and/or chemical specific testing for toxicity identification and characterization in a planned 

sequence to expeditiously locate the source(s) of toxicity and 

evaluate the effectiveness of pollution control actions and/or 

inplant modifications toward attaining compliance with a permit 

limit. The requirement for a TRE is usually based on a 

finding of whole effluent toxicity as defined in the permit. A plan with an implementation schedule is then developed to 

achieve compliance. Investigative approaches include 

causative agent identification and toxicity treatability. 

1. Requiring TRE Plans 

TRE's can be triggered: 1) whenever there is a 

violation of a toxicity limit that prompts enforcement 

action or 2) from a permit condition that calls for a 

toxicity elimination plan within a specified time 

whenever toxicity is found. The enforcement action 

such as a 309(a) administrative order or State 

equivalent, or judicial action then directs the 

permittee to take prescribed steps according to a 

compliance schedule to eliminate the toxicity. This 

schedule should be incorporated into the permit, an 

administrative order, or judicial order and compliance 

with the schedule should be tracked through PCS. 

2. Compliance Determination Followup 

Compliance status must be assessed following the 

accomplishment of a TRE plan using the most efficient and effective methods available. These methods 

include site visits, self-monitoring, and inspections. 

B-4-12 
-7- 

Careful attention to quality assurance will assist in 

minimizing the regulatory burden. The method of 

compliance assessment should be determined on a 

case-by-case basis. 

D. Enforcing Toxic Control Permit Conditions 

Enforcement of toxic controls in permits depends upon a clear requirement and the process to resolve the noncompliance. In addition to directly enforceable whole effluent 

limits (acute and chronic, including absolute pass-fail 

limits), permits have contained several other types of 

toxic control conditions: 1) "free from" provisions, 

2) schedules to initiate corrective actions (such as TREs) 

when toxicity is present, and/or 3) schedules to achieve 

compliance where a limit is not currently attained. 

Additional requirements or schedules may be developed 

through 308 letters, but the specific milestones should be 

incorporated into the permit, administrative order or 

State equivalent mechanism, or judicial order to ensure 

they are enforceable. 

1. The Quarterly Noncompliance Report (QNCR) 

Violations of permit conditions are tracked and 

reported as follows: 

a. Effluent Violations 

Each exceedance of a directly enforceable whole 

effluent toxicity limit is of concern to the 

regulatory agency and, therefore, qualifies 

as meeting the VRAC requiring professional 

review (see section IV.A.2.). 

These violations must be reported on the QNCR 

if the violation is determined through professional review to have the potential to have 

caused a water quality impact. 

All QNCR-reportable permit effluent violations 

are considered significant noncompliance (SNC). 

b. Schedule Violations 

Compliance schedules to meet new toxic controls 

should be expeditious. Milestones should be 

established to evaluate progress routinely and 

minimize delays. These milestones should be 

tracked and any slippage of 90 days or more 

must be reported on the QNCR. 

B-4-13 
-8- 

The following milestones are considered SNC when 

90 days or more overdue: submit plan/schedule 

to conduct TRE, initiate TRE, submit test results, 

submit implementation plan/schedule (if appropriate), start construction, end conrtruction, 

and attain compliance with permit. 

c. Reporting/Other Violations 

Violation of other toxic control requirements (including reports) will be reported using criteria that are applied to comparable NPDES 

permit conditions. For example, failure to 

submit a report within 30 days after the due 

date or submittal of an inaccurate or inadequate 

report will be reportable noncompliance (on 

the QNCR). 

Only failure to submit toxicity limit selfmonitoring reports or final TRE progress reports indicating compliance will be SNC when 30 days 

or more overdue. 

Resolution (bringing into compliance) of all three 

types of permit violations (effluent, schedule, 

and reporting/other) will be through timely and 

appropriate enforcement that is consistent with 

EPA Oversight Guidance. Administering agencies are expected to bring violators back into compliance 

or take formal enforcement action against facilities 

that appear on the QNCR and are in SNC: otherwise, 

after two or more quarters the facility must be 

listed on the Exceptions List. 

2. Approaches to Enforcement of Effluent Limitations 

In the case of noncompliance with whole effluent 

toxicity limitations, any formal enforcement action 

will be tailored to the specific violation and remedial 

actions required. In some instances, a Toxicity Reduction Evaluation (TRE) may be appropriate. However, 

where directly enforceable toxicity-based limits are 

used, the TRE is not an acceptable enforcement response 

to toxicity noncoqiance if it requires only additional 

monitoring without a requirement to determine appropriate remedial actions and ultimately compliance with the 

limit. 

If the Regions or States use administrative 

enforcement for violations of toxic requirements, 

such actions should require compliance by a date 

certain, according to a set schedule, and an 

B-4-14 
-9- 

administrative penalty should be considered.1 

Failure to comply with an Administrative Order 

schedule within 90 days indicates a schedule delay 

that may affect the final compliance date and a 

judicial referral is the normal response. In instances 

where toxicity has been measured in areas with potential 

impacts on human health (e.g., public water supplies, fish/shellfish areas, etc.), regions and states 

should presume in favor of judicial action and seek 

immediate injunctive relief (such as temporary restraining order or preliminary injunction). 

In a few highly unusual cases where the permittee has implemented an exhaustive TRE plan2, applied 

appropriate influent and effluent controls3, maintained 

continued compliance with all other effluent limits, 

compliance schedules, monitoring, and other permit 

requirements, but is still unable to attain or maintain 

compliance with the toxicity-based limits, special 

technical evaluation may be warranted and civil penalty relief granted. Solutions in these cases could be 

pursued jointly with expertise from EPA and/or the 

States as well as the permittee. 

Some permittees may be required to perform a 

second TRE subsequent to implementation of remedial 

action. An example of the appropriate use of a 

subsequent TRE is for the correction of new violations 

of whole effluent limitations following a period of 

lFedera1 Administrative penalty orders must be linked to violations 

of underlying permit requirements and schedules. 

2See Methods for Aquatic Toxicity Identification Evaluations, 

Phase I, Toxicity Characterization Procedures, EPA-600/3-88/035, 

Table 1. An exhaustive TRE plan covers three areas: causative 

agent identification/toxicity treatability; influent/effluent 

control; and attainment of continued compliance. A listing of 

EPA protocols for TREs can be found in Section V (pages 11 and 

12). 

3For industrial permittees, the facility must be well-operated 

to achieve all water quality-based, chemical specific, or BAT 

limits, exhibit proper 0 & M and effective BMPs, and control 

toxics through appropriate chemical substitution and treatment. 

For POTW permittees, the facility must be well-operated to 

achieve all water quality-based, chemical specific, or secondary limits as appropriate, adequately implement its approved pretreatment program, develop local limits to control toxicity, and 

implement additional treatment. 

B-4-15 
- 10 - 

sustained compliance (6 months or greater in duration) 

indicating a different problem from that addressed 

in the initial TRE. 

3. Enforcement of Compliance Schedule and Reporting 

Requirements 

In a number of instances, the primary requirements in the permits to address toxicity 

will be schedules for adoption and implementation of biomonitoring plans, or submission of reports verifying TREs or other similar reporting requirements. Regions and States should consider any failure (1) to conduct self-monitoring according 

to EPA and State requirements, (2) to meet TRE 

schedules within 90 days, or (3) to submit reports 

within 30 days of the specified deadline as SNC. 

Such violations should receive equivalent enforcement follow-up as outlined above. 

4. Use of Administrative Orders With Penalties 

In addition to the formal enforcement actions 

to require remedial actions, Regions and States 

should presume that penalty AO's or State equiva- lents can be issued for underlying permit violations 

in which a formal enforcement action is appropriate. 

Headquarters will also provide Regions and States 

with guidance and examples as to how the current 

CWA penalty policy can be adjusted. 

5. Enforcement Models and Special Remedies 

OWEP and OECM will develop standard pleadings and language for remedial activities and compliance milestones to assist Regions and States in addressing violations of toxicity or water quality-based permit limits. Products will include model litigation reports, model complaints and consent decrees, 

and revised penalty policy or penalty algorithm and should be completed in early FY 1989. 

54-16 
- 11 - 

v. Summary of Principal Activities and Products 

A. 

B. 

c. 

D. 

E. 

Compliance Tracking and Review guidance 

1. PCS Coding Guidance - May, 1987; revision 

2nd Quarter 1989 

2. Review Criteria for Self-monitoring Data (draft attached) 

Inspections and Quality Assurance 

1. Revised NPDES Compliance Inspection Manual - 

May 1988. 

2. Quality Assurance Guidance - 3rd Quarter FY 1989. 

3. Biomonitoring Inspection Training Module - August 1988. 

4. Additions of a reference toxicant to DMRQA program - (to be determined) 

Toxic8 Enforcement 

1. Administrative and Civil Penalty Guidance - 4th 

Quarter FY 1989 

2. Model Pleadings and Complaints - 2nd Quarter 1989 

3. EMS Revision - 2nd Quarter FY 1989 

Permitting Consistency 

1. Basic Permitting Principles - 2nd Quarter FY 1989 

Toxicity Reduction Evaluations 

1. Generalized Methology for Conducting Industrial 

Toxicity Reduction Evaluations - 2nd Quarter 

FY 1989 

2. Toxicity Reduction Evaluation Protocol for 

Municipal Wastewater Treatment Plants - 2nd Quarter 

FY 1989 

B-4-17 
- 12 - 

3. Methods for Aquatic Toxicity Indentification 

Evaluations 

a. Phase I. 

b. Phase II. 

C. Phase III. 

Toxicity Characterization 

Procedures, EPA-600/3-88/034- 

September 1988 

Toxicity Identification 

Procedures, EPA-600/3-88/035- 

2nd Quarter 1989 

Toxicity Confirmation ProceduresEPA-600/3-88/036 d Quarter 

FY 1989 

84-l 8 
APPENDIX B-5 

QUALITY CONTROL FACT SHEETS 
Attachment 

Quality Control Fact Sheet for Self-Biomonitoring 

Acute/Chronic Toxicity Test Data 

Permit No. 

Facility Name 

Facility Location 

Laboratory Investigator 

Permit Requirements 

Sampling Location 

Limit 

Type of Test 

Test Results 

LC50/EC50/NOEC/IC25 

Quality Control Summary 

Date of Sample 

Control Mortality % 

Type of Sample 

Test Duration 

Test Organism Age 

95 Percent Confidence Interval 

Dates of Test 

Control Mean Dry Weight 

Temperature maintained within ±2°C of test temperature? Yes No 

Dissolved oxygen levels always greater than 40 percent saturation? Yes No 

Loading factor for all exposure chambers less than or equal to maximum allowed for the test type 

and temperature? Yes No 

Do the test results indicate a direct relationship between effluent concentration and response of 

the test organism (i.e., more deaths occur at the highest effluent concentrations)? Yes 

No 

B-5-1 
APPENDIX B-6 

CASE DECISIONS ON WHOLE EFFLUENT TOXICITY 
CASE SUMMARY 

Natural Resources Inc. v. EPA, Defense 859 F.2d 159 Council, (D.C. Cir. 1988). 

This consolidated case, which arose from EPA’s promulgation of various National Pollutant Discharge 

Elimination System regulations, addresses a multitude of issues. The following paragraphs note issues 

particularly relevant to this document. 

• The Court held that EPA has the authority to express permit limitations in terms of toxicity as long as 

the limits reflect the appropriate requirements of the Clean Water Act (CWA), as provided in 40 CFR 

125.3(c)(4). The Court concluded that although toxicity appears to be an attribute of pollutants 

rather than a pollutant itself, the CWA (by means of the broad definition of “pollutant” in section 

502(6)) authorizes the use of toxicity to regulate effluents. 

• Industry asked the Court to address several other issues related to setting toxicity limitations (whether 

EPA failed to demonstrate the existence of a reliable methodology for setting toxicity limits and 

whether EPA’s use of toxicity to set water quality-based limitations to meet “narrative” State water 

quality standards represents an impermissible trespass on the State’s right to set water quality 

standards). However, the Court did not regard these issues to be adequately developed (“ripe”) for 

review in this case. 

• 

• 

The Court disagreed with industry’s assertions that EPA’s 1984 policy statement (“Development of 

Water Quality-Based Permit Limitations for Toxic Pollutants: National Policy,” 49 Federal Register 

9016 [March 9, 1984]) and draft Technical Support Document (“TSD”) were “rules” requiring notice and 

comment under the Administrative Procedure Act, 5 USC 553. The Court noted that informal 

rulemaking regarding 40 CFR 125.3(c)(4), which was pending between 1980 and 1984, did not limit 

Agency information gathering to the issuance of new or revised notices of proposed rulemaking, and 

the two documents did not have independent legal value. (In other words, the EPA national policy 

and the TSD were not binding norms but general statements of policy/guidance.) 

Industry also challenged EPA’s refusal to provide an affirmative upset defense to noncompliance with 

water quality-based limits. The Court indicated that the CWA does not expressly allow such an upset 

defense, and, upon considering the Act’s structure and legislative history, it could discern no 

congressional intent to provide for the defense in water quality permitting. Significantly, in 

reaching this position, the Court relied heavily upon the language and legislative history of CWA 

Section 301(b)(1)(C), by which Congress clearly did not relate compliance with water quality-based 

limitations to the capabilities of technology. In the Court’s view, “Congress had a deep respect for 

the sanctity of water quality standards and a firm conviction of the need for technology-forcing 

measures.” 895 F.2d at 208-09. However, the Court concluded that EPA had acted arbitrarily in 

dismissing the defense as impracticable, and directed EPA to conduct further proceedings on the issue. 

l Finally, the Court rejected challenges to EPA’s regulations governing State public participation 

requirements and penalty levels. In deciding these issues, the Court noted Congressional desire for 

nationally uniform effluent limitations as reflected in the legislative history of the 1972 CWA. The 

Court stated : 

Uniformity is indeed a recurrent theme in the Act, a direct manifestation of concern that the permit 

program be standardized to avoid the “industrial equivalent of forum shopping” and the creation of 

“pollution havens” by migration of dischargers to areas having lower pollution standards (859 F.2d at 

174 [footnotes omitted] and see accompanying footnotes 17-20 citing various provisions of the 

legislative history of the 1972 CWA). 

B-6-1 
APPENDIX C 

AMBIENT TOXICITY TESTING AND DATA ANALYSIS 
Ambient Toxicity Analysis 

Ambient toxicity testing procedures are useful where measurement of toxicity levels after discharge is important 

in the assessment of toxic effluent impact. This is particularly true where impact is caused by the presence of 

multiple point sources. The purpose of this testing is to provide an analysis of toxicity levels instream from 

whatever sources of toxicity are affecting the receiving water. 

Procedures 

The basic ambient toxicity testing procedure is to expose test organisms to receiving water samples taken from 

selected sampling stations above, at, and below the discharge point(s). Since effluent concentrations after 

discharge are often relatively low, chronic toxicity tests should be conducted so that the tests are sensitive 

enough for the purpose. 

The methods available for chronic testing of sufficiently short duration are limited. Two organisms for which 

short-term chronic toxicity tests are available are Pimephales promelas and Ceriodaphnia sp. 

The following procedures are used: 

• 

• 

• 

• 

• 

Select instream sampling stations based on the mixing characteristics involved in the specific discharge situation. 

Collect a daily grab sample or a daily composite sample of receiving water from each station. 

Use a renewal testing method to expose test organisms to the daily samples collected at each station. 

Use an appropriate number of replicates (10 for Ceriodaphnia) for each sampling station. No dilution 

series is required where screening is the primary goal. 

Conduct testing at a low-flow period, although it is not necessary to conduct the tests at the critical 

low-flow period. Testing is best when relatively stable flow occurs during the test period. 

Record the results of the testing in the format shown in Table C-1. The survival of the test organisms 

and the effect on their growth or reproduction are used as endpoints. Figure C-l plots the results in 

graphic form so that the pattern of ambient toxicity can be observed. 

C-l 
Table C-l. Young Production and Percent Survival of Cerioduphniu in Ambient 

Toxicity Tests at Ottawa River, Lima, Ohio 

River Young Final Dailv Survival 

Station Station Description Mile Female SD Survival 1 2 3 4 5 6 7 

1 Above Lima 46.0 15.5 8.0 90 100 100 100 90 90 90 90 

2 Above STP 37.7 14.1 2.1 0 100 100 100 100 90 10 0 ; 

3 Below STP 37.4 0 - 0 100 100 10 0 0 0 0 

3A Midway between 

STP and refinery 37.3 0 - 0 100 100 10 0 0 0 0 

36 Above refinery 37.1 0.4 - 0 90 90 40 0 0 0 0 

4 Above chemical plant 36.9 7.5 3.6 10 4A Below chemical plant 36.3 11.1 4.6 30 100 100 100 100 100 50 10 I 

100 100 100 100 100 40 30 

5 Shawnee Bridge 36.4 5.7 4.0 0 9090909090600~ 

6 Route 117 32.5 12.6 3.8 10 100 100 100 100 100 100 10 

i 8’ Allentown 28.8 16.8 6.1 100 100 100 100 100 100 100 100 1 

Rimer 16.0 17.4 9.5 100 90909090 908080 

BA “Boonie” Station 8.0 25.0 3.3 100 100 100 100 100 100 100 100 

9 Kalida 1.0 25.6 5.5 100 100 100 100 100 100 100 100 

I - I I I t 

60 65 45 32 16 0 

River Kilometers 

Figure C-l. Cerioduphniu Young Production in Water from Various Stream 

Stations on the Ottawa River, Lima, Ohio 

c-2 
Selecting Sampling Stations 

The selection of sampling stations is determined by the characteristics of the site. When determining stations, 

consider the following factors: 

l Mixing and flow-The mixing characteristics of the discharge site are useful to determine the 

placement of sampling stations. Knowledge of concentration isopleths allows the regulatory 

authority to place stations at locations instream that correspond to concentrations measured in the 

dilution series in the effluent tests. For example, where effluent testing shows the effluent no 

observed effect concentration is 10 percent, an instream station should be placed where dilution is 

estimated to create a lo-percent instream waste concentration. In this way, the size of a toxic plume 

can be measured. Sampling stations should be placed where the effluents exist at relatively constant 

and relatively specific concentrations. Test at specific low-flow conditions, if possible. Presence of 

tributaries or other sources of dilution will influence positions and numbers of stations. Where 

smaller tributaries have several point sources on them, treat the tributary as a point source. Obvious 

nonpoint source areas also should be used to set stations. 

l Existing biological data-Where biosurvey data are available, sampling station location should be 

influenced by the more obvious trends in impact. In particular, control stations and recovery stations 

can be determined by biosurvey data. 

. Single point sources-Single point source situations should be bracketed with an above station, an 

immediate mixing station, several intermediate stations corresponding to different instream 

concentrations, and a recovery station. Of course, a control station should be established. 

l Presence of other point sources-Multiple point source situations require the ptacement of more 

stations between discharge points. Each source should be bracketed by sampling stations. 

There are four areas or zones that can be recognized when establishing the sampling stations for ambient 

toxicity testing: 

Zone l-An upstream zone before the effluent enters 

Zone 2-A zone of mixing 

Zone 3-A zone after mixing and before additional dilution water enters 

Zone 4-A zone where additional dilution occurs either from effluents or tributaries. 

All possible combinations of occurrences are not practical to discuss but must be sorted out for each site. Some 

generalizations are important to mention: 

l Any upstream sources of contaminants, such as other discharges, will confound the individual effects 

of a downstream discharge. For example, Zone 3 of the downstream discharge may occur in Zone 4 of 

an upstream discharge. This does not invalidate the measurement of ambient toxicity. It only makes 

it difficult to attribute amounts of response to each individual discharge. Response to the instream 

mixture is what is measured. 

l Careful location of sampling stations in Zone 3 is critical. Zone 3 is the only place where toxicity 

decay rates of any one discharger can be measured and then only if there are no upstream discharges, or 

if there are, only if that upstream effluent is stable in that reach. 

l In Zone 4, not only is degradation of the effluent toxicity occurring, but there is dilution of it by 

other effluents and tributaries. Depending on the site circumstances, one may not be able to learn 

anything about the ambient toxicity characteristics of the effluent of concern in this zone. 

l To emphasize, what can be measured in each zone depends on the above considerations. In the more 

complex situation, only an estimate of ambient toxicity at each station can be obtained. No 

information about one effluent’s toxicity decay rate will be available where several toxic effluents 

mix. In the most simple situation of one discharge and no dilution downstream for a long distance, 

Zone 3 will be large enough to get a good measure of toxicity decay. 

c-3