EPA RESPONSE 

TO EXTERNAL PEER REVIEW COMMENTS

on the

DRAFT AQUATIC LIFE AMBIENT ESTUARINE/MARINE 

WATER QUALITY CRITERIA FOR COPPER

July 2016

Office of Water

U.S. Environmental Protection Agency

Washington, DC
ii

TABLE OF CONTENTS

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

1.1 Background...................................................................................................................................... 1

1.2 Peer Reviewers................................................................................................................................ 1

1.3 Review Materials Provided.............................................................................................................. 1

1.4 Charge Questions............................................................................................................................. 1

2 EXTERNAL PEER REVIEWER COMMENTS AND EPA RESPONSES, ORGANIZED BY 

CHARGE QUESTION ..................................................................................................................................... 2

2.1 Charge Question 1........................................................................................................................ 3

2.2 Charge Question 2........................................................................................................................ 9

2.3 Charge Question 3...................................................................................................................... 16

2.4 Charge Question 4...................................................................................................................... 20

2.5 Other Comments Provided ......................................................................................................... 22

3 REFERENCES CITED BY REVIEWERS......................................................................................... 24
1

1 INTRODUCTION

EPA submitted its Draft Aquatic Life Ambient Estuarine/Marine Water Quality Criteria (AWQC) for Copper

for contractor-led independent, external peer review from November 24, 2015 to December 11, 2015. The 

external peer reviewers provided their independent responses to EPA’s charge questions. This report 

documents the EPA’s response to the comments provided to EPA. 

This report presents the four peer review charge questions and individual reviewer comments (verbatim) in 

Sections 2.1 through 2.5. Section 2.6 presents additional minor comments provided by two reviewers. New 

information (e.g., references) provided by reviewers is presented in Section 3. EPA separated each reviewer’s 

comments by charge question into distinct topics and responded to each topic individually, and also indicated

how the estuarine/marine copper criteria document was revised in response to peer reviewer comments.

1.1 BACKGROUND

EPA’s Office of Water is developing the recommended ambient WQC for copper in estuarine/marine waters 

through its authority under §304(a) of the Clean Water Act (CWA). The Agency is developing the water 

quality criteria to protect aquatic life and aquatic-dependent wildlife from the presence of copper in 

estuarine/marine environments in order to reflect the latest scientific knowledge.

EPA’s Draft Aquatic Life Ambient Estuarine/Marine Water Quality Criteria for Copper presented acute and 

chronic criteria expressed as concentrations of copper in estuarine/marine waters (dissolved). The 2015 draft 

copper criteria update utilized the recently developed marine BLM to provide updated acute and chronic 

water quality criteria for copper in estuarine/marine waters. The BLM is based on the premise that toxicity is 

related to the amount of metal bound to a biochemical site (the biotic ligand) and that binding is related to 

total dissolved metal and complexing ligands concentrations in the water. The draft criteria also included 

updated toxicity test information for copper effects on estuarine/marine aquatic species. This draft differed

from previous estuarine/marine copper criteria which were based on empirical relationships between toxicity 

and water hardness.

1.2 PEER REVIEWERS

An EPA contractor identified and selected five reviewers who met the technical selection criteria provided by 

EPA and who had no conflict of interest in performing this review.

The EPA contractor provided reviewers with instructions, the review document (including appendices), the 

charge to reviewers) prepared by EPA, and supporting reference materials as described in the charge. 

Reviewers worked individually to develop written comments in response to the charge questions. 

1.3 REVIEW MATERIALS PROVIDED

 Draft Saltwater BLM Cu (11-23-15 draft).docx 

 Marine BLM ver 0043.zip

1.4 CHARGE QUESTIONS

1. Please comment on the overall clarity of the document and construction as it relates to the derivation 

of each criterion.

2. Please comment on the technical approach used to derive the draft copper criteria; is it logical, does 

the science support the conclusion, and is it consistent with the protection of estuarine/marine aquatic 

life from acute, chronic, and bioaccumulative effects?
2

3. (a) Please comment on the data used to derive the revised criteria, including data adequacy/ 

comprehensiveness, and the appropriateness of the data selected and/or excluded from the derivation 

of the draft criteria. 

(b) Are there other relevant data that you are aware of that should be included? If so, please provide 

the criteria.

4. Are the derived criteria appropriately protective of listed species and commercially and recreationally 

important species?

2 EXTERNAL PEER REVIEWER COMMENTS AND EPA RESPONSES, ORGANIZED BY 

CHARGE QUESTION

The following tables list the charge questions submitted to the external peer reviewers, the external peer 

reviewers’ comments regarding those questions (broken into distinct topics), and EPA’s responses to the peer 

reviewers’ comments. EPA revised the 2016 draft considering the external peer review comments, and noted 

in the table where the draft criteria document was edited.
3

2.1 CHARGE QUESTION 1

1. Please comment on the overall clarity of the document and construction as it relates to the derivation of each criterion.

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 1

EPA Response

Revision 

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Reviewer 1 The document is reasonably clear, albeit a bit redundant in that 

some of the same language is recycled several times in describing 

the Biotic Ligand Model (BLM).

Thank you for your comment. The document was revised to 

eliminate unnecessary redundancies. However, some 

repetition was intentionally written into the document to tie 

sections together and facilitate use by readers who may only 

access specific document sections.

Various 

sections

Reviewer 1 The language regarding the derivation of the final Acute to 

Chronic Ratio (ACR) is a bit convoluted in the use of freshwater 

values.

The language used to describe the derivation of the Final 

Acute to Chronic Ratio (FACR) was clarified. 

Section 3.6.2

Reviewer 2 I believe this is a very good work product and should be quite 

useful for those entities charged with regulating copper in marine 

and estuarine waters.

Thank you for your comment. No edits 

needed.

Reviewer 2 Problem formulation. Well done, nicely laid out and exposure 

scenarios described well.

Thank you for your comment. No edits 

needed.

Reviewer 2 Case Study. Nice illustration and should serve as educational tool.

The comparison between freshwater and marine scenarios is also 

useful and should benefit the reader. 

Thank you for your comment. No edits 

needed.

Reviewer 2 Figure 5 was particularly useful and leads the reader to figure 6.

Major drawback: It is an equilibrium model and does not allow 

for consideration of pulsed or episodic exposure with organism 

recovery. This is not necessarily a criticism of the document. 

Rather, it should be a consideration for future research.

The reviewer is correct in that pulsed exposures are not 

considered, consistent with standard ecological assessment 

practices in the U.S. and many international jurisdictions. EPA 

agrees that consideration of pulsed or episodic exposures with 

organism recovery would be a useful area of future research

by the scientific community.

No edits 

needed.

Reviewer 2 How does the varying salinity in estuaries pose special 

challenges?

Section 2.4 provides a detailed discussion of the BLM’s 

function in environments with varying salinities.

Section 2.4

Reviewer 2 Given the obvious mechanism of phytotoxicity for copper, it is 

surprising that little data exists for estuarine plants. However, it is 

likely that the same mechanisms that make estuarine plants 

tolerant to salinity likely make them less sensitive to metals such 

as copper.

Thank you for your comment. There are limited data for 

estuarine plants, as noted. However, an additional analysis was 

performed to BLM normalize plant effect concentrations to

further characterize the protectiveness of the chronic criterion 

to estuarine/marine plants.

Section 4.4
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Reviewer External Peer Reviewer Comments Regarding Charge 

Question 1

EPA Response

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Reviewer 3 The text is clearly written. There are some repetitions but they are 

probably useful to remind the reader about limits and scope of the 

work. It is however difficult for the reader to appreciate the rigor 

of the approach without reading some of the cited references such 

as Chadwick et al (2008) which may not be easily accessible. 

Perhaps an appendix could be added.

Thank you for your comment. The document was revised to 

eliminate unnecessary redundancies. As the reviewer noted, 

however, some repetition was intentionally written into the 

document to tie sections together and facilitate use by readers 

who may only access specific document sections. A direct 

clickable link to the Chadwick document was added in the 

reference section to facilitate document access by the end user.

Various 

sections.

Reviewer 3 The use of the term “bioavailable” is, in my opinion, not always 

correct. Because of the dynamic nature of metal binding, one 

cannot say that a particular metal species is not bioavailable. This 

was clearly laid out in the original Morel book [1] as well as in 

Campbell [2]. Here is part of page 55 of the latter reference:

I have noted many statements with such a bioavailability 

misconcept being conveyed: p. 1, l. 15; p. 14 (4 times); p. 47 

penultimate line.

The reviewer is not correct in the implication that the BLM 

uses one chemical species as the definition of “bioavailable”. 

The BLM, for example, does not simply predict free metal ion 

and equate that with bioavailability. The free metal ion 

concentration at the BLM-predicted effect concentration will 

change with changing chemical conditions. The interpretation 

of bioavailability used by the BLM is consistent with the text 

cited by the reviewer.

No edits 

needed.

Reviewer 3 Figures 4, 5, 6 and 7 are lacking information for the reader to 

understand them. The meaning of the inserted legends is 

unknown. The legend of figure 4 says “Values collapse into a 

single dose response when compared with measured copper 

accumulation” but it is not clear what this refers to. In figure 5 

dotted lines are not described.

The phrase “collapse into a single dose response” was 

referring to a comparison of the same toxicity data plotted 

versus dissolved copper, which showed different dose 

response relationships, or versus copper accumulation (as in 

Figure 4) which were now similar. Since the version of the 

figure based on dissolved copper was deleted, the comparison 

is no longer relevant and the text was revised accordingly.

Section 2.4
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Reviewer External Peer Reviewer Comments Regarding Charge 

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EPA Response

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Reviewer 3 Section 2.5 (pp. 22-24) seems superfluous. Consider removing. Thank you for your comment. The inclusion of a conceptual 

model is informative and consistent with relating the copper 

criteria to a broader risk assessment framework, and is 

consistent with EPA’s Ecological Risk Assessment Guidelines 

(1998)

No edits 

needed.

Reviewer 3 P. 40, middle: “Application of the BLM may reduce, if not 

eliminate, the need for site-specific modifications to account for 

site-specific chemistry influences on metal toxicity.” I would 

argue that the use of the BLM is another way to account for site 

specific differences. Consider rephrasing.

The referenced text was revised to clarify that the BLM 

provides a model that can be used to account for the influence 

of important site-specific parameters, in this case temperature, 

pH, DOC, and salinity, on copper toxicity. 

Reviewer 3 P. 11. Last paragraph is incomplete and incoherent but I was 

instructed to ignore this paragraph.

The text was revised to be complete and to describe the 

primary form of copper in estuarine and marine environments.

Reviewer 3 P. 46, Figure 11: I am not convinced this figure is useful with 

only two values. Note also that the y-axis label should read 

copper and not cadmium.

The text was revised as suggested and Figure 11 was retained. Figure 11

Reviewer 4 Overall the document is well written and clear as to how the 

criteria are derived. I do have a few minor comments, however, 

on areas that could be clarified. 

Thank you for your comment. No edits 

needed.

Reviewer 4 Pgs. 17-18: The discussion about Figs 4 and 5 is a little confusing 

the way it’s presented.

The text was modified to clarify. Section 2.4

Reviewer 4 Fig. 4: Define “(N)” and “(S)”. N and S are sample names. The figure and text was revised to 

clarify.

Figure 4 and 5

Reviewer 4 Fig. 5: Where is the “convergence”? Please clarify the “single 

model representation”.

See response to reviewer 3’s comment above. Section 2.4

Reviewer 5 Overall the draft document content is comprehensive, accurate, 

and persuasive. It is well written and well organized. The cited 

references represent major works in the related fields and these 

are overall supportive of the Draft Update of Aquatic Life 

Ambient/Marine Water Quality Criteria for Copper (herein 

referred to as MWQC-Cu). The Chadwick et al. (2008) citation 

requires review and update (see detail below). The overall report 

is well-written in a clear and communicative style. The report 

heading and subheadings are helpful to reader and present an 

organized development of the supporting work for the draft acute 

Thank you for your comment. The Chadwick reference was 

updated to the final report and a hyperlink was added to 

facilitate access to this document. The fonts were reviewed, 

though some of the differences in the fonts are by design to 

differentiate between the different header levels. 

No edits 

needed.
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Reviewer External Peer Reviewer Comments Regarding Charge 

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and chronic criterion. The Table of Contents has font mismatches. 

The List of Figures, List of Tables, List of Appendices and 

Acronyms list are complete. In my reading of the report text, the 

balance of number of figures and number of table to support the 

development and explanation of the criterion development was 

satisfyingly complete. The document is well edited for correct 

grammar and spelling, clear sentence structure, and informative 

paragraph development. Paragraph transitions are present and 

logical, and maintain the flow of thought throughout the report. 

Reviewer 5 The Introduction provides overall sufficient background for 

copper and previews major points in aquatic ecosystem concerns 

and concomitant regulatory science development. Section 2.1, 

Overview of Copper Sources and Occur, page 5 paragraph 1 

could be broadened to also include copper sulfate use in dairy 

cattle foot baths, an emerging source of problematic copper 

release to the environment because of animal hygiene and manure 

management practices associated with large animal agriculture 

operations. For example in the Agricultural Extension 

publication: 

http://articles.extension.org/pages/22177/copper-sulfate-footbaths-on-dairies-and-crop-toxicities 

and in

Jokela, WE, et al. (2010) Manure Nutrient Content on 

Vermont Dairy Farms: Long-Term Trends and 

Relationships

COMMUNICATIONS IN SOIL SCIENCE AND 

PLANT ANALYSIS

Volume: 41 Issue: 5 Pages: 623-637

DOI: 10.1080/00103620903531193

Text was added to include dairy cattle foot baths as a potential 

source of copper to the environment.

Section 2.1

Reviewer 5 Directly germane and important in the development of the EFT of 

marine copper, yet absent in the citations to this report, is a 

significant review by Turner (2010): 

Turner, A (2010) Marine pollution from antifouling paint 

particles

Antifouling paint particles were added as a potential source of 

copper to the environment and the two summary/review 

articles were cited and added to the references.

Section 2.1
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Reviewer External Peer Reviewer Comments Regarding Charge 

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MARINE POLLUTION BULLETIN

Volume: 60 Issue: 2 Pages: 159-171

DOI: 10.1016/j.marpolbul.2009.12.004

Thomas, KV and Brooks, S (2010) The environmental 

fate and effects of antifouling paint biocides

BIOFOULING

Volume: 26 Issue: 1 Pages: 73-88

DOI: 10.1080/08927010903216564

The same could be said of the review by Kiaune and 

Singhasemanon (2011):

Kiaune, L and Singhasemanon, N (2011) Pesticidal 

Copper (I) Oxide: Environmental Fate and Aquatic 

Toxicity. Edited by: Whitacre, DM

REVIEWS OF ENVIRONMENTAL 

CONTAMINATION AND TOXICOLOGY, VOL 213. 

Book Series: REVIEWS OF ENVIRONMENTAL 

CONTAMINATION AND TOXICOLOGY

Volume: 213 Pages: 1-26

DOI: 10.1007/978-1-4419-9860-6_1

Reviewer 5 Copper flux from sediments is an important EFT dynamic in 

marine ecosystems and a source of exposure for benthic 

organisms and may be a significant driver of Cu speciation and 

concentration in the overlaying waters. Section 2.2 of the 

Introduction would be strengthened by a short comment about 

marine sediment Cu geochemistry such as could be developed by 

references such as: 

Skrabal, SA et al. (2000) Pore water distributions of 

dissolved copper and copper-complexing ligands in 

estuarine and coastal marine sediments

GEOCHIMICA ET COSMOCHIMICA ACTA

Volume: 64 Issue: 11 Pages: 1843-1857

DOI: 10.1016/S0016-7037(99)00387-7

Published: JUN 2000

An additional discussion was added to the document to discuss 

the Cu geochemistry from marine sediments using the 

reference you provided.

Section 2.2
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Reviewer External Peer Reviewer Comments Regarding Charge 

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Reviewer 5 Section 2.4, Overview of Historic and BLM Criteria 

Development Methods, would be improved with the citation and 

short distillation of Erickson (2013), a significant review 

reference describing BLM strengths and cautionary weaknesses:

The biotic ligand model approach for addressing effects 

of exposure water chemistry on aquatic toxicity of 

metals: Genesis and challenges

ENVIRONMENTAL TOXICOLOGY AND 

CHEMISTRY

Volume: 32 Issue: 6 Pages: 1212-1214

DOI: 10.1002/etc.2222

Erickson (2013) would also provide significant support 

for the discussion of MWQC-Cu Section 3.8.3, BLM 

Uncertainties and Performance.

Modifications to the text and reference to Erickson were

added, as suggested.

Section 2.4
9

2.2 CHARGE QUESTION 2

2. Please comment on the technical approach used to derive the draft copper criteria; is it logical, does the science support the conclusion, and 

is it consistent with the protection of estuarine/marine aquatic life from acute, chronic, and bioaccumulative effects??

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 2 EPA Response

Revision 

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Reviewer 1 I have a lot of respect for the scientific merit associated with the 

BLM. If toxicity of Cu was exclusively based on surficial binding 

and associated osmoregulatory effects, the approach used in this 

WQC would be fine. Unfortunately, a lot of credible science is 

ignored, and a WQC is being proposed that only uses a portion of 

our scientific understanding. The criteria is based on a narrow 

literature evaluation of copper toxicity. It ignores literature that 

shows dietary Cu bioaccumulation and effects (e.g. Bielmeyer 

paper that was not considered because the exposure route was via 

diet). It only acknowledges a segment of what is known about Cu 

toxicity in general (all biota) and in aquatic organisms 

specifically. The oxidative toxicity of Cu is ignored completely 

despite dozens of papers that describe it in aquatic organisms. 

I've attached a new book chapter that may be helpful. (Bielmeyer 

and Grosell, Chapter 5: Emerging issue in marine metal toxicity.)

EPA concurs with the reviewer about the difficulty in 

characterizing dietary exposure and establishing critical tissue 

effects thresholds for bioaccumulated metals. 

Text has been added to discuss these points and incorporate 

the work of other researchers who discuss copper 

bioaccumulation and dietary exposure in detail and the 

uncertainties currently associated with its evaluation. In 

particular, text was added to detail how copper can 

bioaccumulate in aquatic organisms through multiple exposure 

routes including ingestion and direct exposure, and how total 

uptake depends on the copper concentration, exposure route 

and the duration of exposure.

Information regarding the oxidative toxicity of copper has 

been added to Section 2.3.

Section 4.3.1 

(a new section)

Reviewer 1 The treatment of bioaccumulative effects is terribly inadequate, 

particularly in light of the lack of chronic data. It is well 

established that invertebrates receive considerable tissue 

concentrations of metals from their diets. It is also well 

established that Cu that is not detoxified can be a potent prooxidant. This is acknowledged as only occurring in mammals in 

this document despite abundant literature describing this 

phenomenon in aquatic organisms. It seems that EPA is only 

acknowledging the potential for toxicity via dissolved exposures. 

This is incomplete. It seems as though EPA discounts metal 

bioaccumulation as potentially problematic because a single 

tissue effects threshold does not exist. If toxicity can result from 

dietary exposures (shown in the literature), there should be no 

problem in using the dissolved concentrations that the diet was 

exposed to as a descriptor of exposure. 

Text has been added to discuss these points and incorporate 

the work of other researchers who discuss copper 

bioaccumulation and dietary exposure in detail and the 

uncertainties currently associated with its evaluation. In 

particular, text was added to detail how copper can 

bioaccumulate in aquatic organisms through multiple exposure 

routes including ingestion and direct exposure, and how total 

uptake depends on the copper concentration, exposure route 

and the duration of exposure.

In addition, it should be noted that the larval life stage of the 

invertebrate Mytilus edulis (blue mussel) is the most acutely 

sensitive species in the copper database, and that this life stage 

does not feed during development.

Section 4.3.1 

(a new section)
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Reviewer External Peer Reviewer Comments Regarding Charge 

Question 2 EPA Response

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Reviewer 1 P. 1: “The biotic ligand is the gill surface and the site of toxicity 

on the organism”. This statement is only partially true. Gill 

binding is associated with toxicity, most likely via interactions 

with ion transport systems and carbonic anhydrase. However this 

is not the only way copper causes toxicity (see comment above). 

Bioaccumulated Cu (from all exposure routes) has the potential to 

be toxic as well. 

The text was modified to refer to biological membranes rather 

than only the “gill” as the biotic ligand.

Section 1.0

Section 2.4

Reviewer 1 P. 12: Figure 2 is not particularly informative. Figure 2 has been revised to provide a clearer depiction of 

copper characteristics in estuarine/marine waters.

Figure 2

Reviewer 1 P. 12: The overview of toxicity is woefully inadequate. This is an 

exceptionally well-studied metal. There is no reason for this 

section to not provide a comprehensive overview of what is 

known about Cu toxicity. 

Section 2.3 has been revised to provide a more detailed and 

comprehensive summary of copper toxicity to 

estuarine/marine organisms. 

Section 2.3

Reviewer 1 P. 13: With all of the work that has examined the bioavailability 

of Cu from sediments, the only thing mentioned is AVS? (AVS is 

not universally recognized and is highly controversial among 

knowledgeable scientists).

A discussion of the bioavailability of copper from marine 

sediments was added to the document.

Section 2.2

Reviewer 1 P. 16 Figure 3: Shouldn’t the anions and their importance in 

complexation reactions be portrayed here?

Figure 3 was revised to include this detail. Figure 3

Reviewer 1 P. 16: Again, the overly simplistic and incomplete view of 

toxicity is expressed here. 

The document includes discussions of copper toxicity 

mediated via water and dietary exposures, and illustrates the

primary toxicity modifying factors that can alter 

bioavailability. Section 2.3 has been revised to provide a more 

detailed and comprehensive summary of copper toxicity to 

estuarine/marine organisms.

Section 2.3

Reviewer 1 P. 17: It is interesting that whole body accumulation values are 

used here. It is interesting that the interpretation is that whole 

body accumulation is related to surficial binding, with surficial 

binding being the cause of toxicity where it could very well be 

that toxicity results from whole body accumulation. Along those 

lines, it opens up the idea that bioaccumulated Cu is potentially 

important, and the simple BLM-only view of the world is not 

complete. 

The accumulation data in question were from short exposures 

designed to only allow surficial binding in experiments with 

embryo larval forms of the organisms. Therefore it is by 

design, and not by assumption, that accumulation in this study 

is equated with surficial binding.

No edits 

needed.
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Reviewer External Peer Reviewer Comments Regarding Charge 

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Reviewer 1 P. 24: The conceptual model includes ingestion but none of the 

acceptable data include ingestion as an exposure route. This is a 

huge source of uncertainty. Importantly, the BLM could be used 

to better understand both direct exposure via water, and ingestion 

pathways because it is well known that water chemistry affects 

Cu uptake in phytoplankton (which is typically accumulative).

Discussion has been added regarding the uncertainty of diet as 

an exposure route.

Section 4.3.1 

(a new section)

Reviewer 1 P. 31: section 2.8.2 check grammar of first sentence. The text was revised to correct. Section 2.8.2

Reviewer 1 P. 33: These criteria apply to marine and estuarine waters......I’m 

very uncomfortable with the language about the stability of 

marine waters and its application to estuarine waters as well 

(which are less stable).

Text was added to clarify the statement about stability was in 

reference to full salinity marine waters. Text was also added to 

discuss the variability of ionic composition in estuarine 

waters, and how this is addressed by the salinity parameter in 

the BLM. 

Section 2.8.3

Reviewer 1 P. 34: I’m not sure about the use of the term “threshold” to 

describe an LC50.

The term is not used to describe the LC50. Rather, the text 

reads, “The LA50s represent the critical threshold 

concentrations at the biotic ligand that result in acute toxicity 

...”. The term threshold is appropriate since it refers to the 

concentration that results in toxicity.

No edits 

needed.

Reviewer 1 P. 38: What is a 96 hour static multi-generational test? The text was edited to clarify the type of test conducted with 

the rotifer Brachionus plicatilis.

Section 3.2

Reviewer 1 P. 39: What if rotifers were fed a diet that was equilibrated to the 

same copper concentrations? Would the toxicity values be 

expected to change? 

This is an interesting question. Unfortunately, the only way to 

determine if the toxicity values would change is to conduct the 

test and these data are not currently available.

No edits

Reviewer 1 P. 41 Table 8: I assume the 2°C is a typo? The text was revised to correct. Table 8

Reviewer 1 P. 46 Figure 11: check Y axis label. This is a copper criterion not 

a cadmium criterion. 

The text was revised to correct. Figure 11

Reviewer 1 It is interesting that copper is used as an aquatic herbicide, yet 

several times in the text it is noted that toxicity to plants is 

comparable to toxicity in animals. Shouldn’t this raise concerns?

The plant data with low effect concentrations were BLM 

normalized to the test conditions to allow comparison to the 

FCV. The results of this analysis were added to the document, 

and suggested (based on available data) that the criteria would 

in most cases also be protective of aquatic plants.

Section 4.4

Reviewer 2 The technical approach is sound and consistent with both 

previous BLM efforts as well as the established methodology for 

developing water quality criteria. Table 3 lays out the data, 

summary statistics and metrics and should be easily understood 

Thank you for your comment. No edits 

needed.
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by the reader. While a little short on chronic data, the results are 

sound and scientifically defensible.

Reviewer 3 I think the use of the BLM is an improvement over the use of 

empirical hardness relationships. The BLM approach is based on 

sound premises and previous successful applications. 

Thank you for your comment. No edits 

needed.

Reviewer 3 P. 17: “An advantage of the BLM is that most of the parameters 

are invariant for different organisms, despite the complexity of 

the modeling framework. All of the thermodynamic constants 

used to simulate inorganic and organic chemical equilibrium 

reactions are determined by characteristics of the metal and the 

available ligands. As such, the constants do not change for 

simulations involving different organisms.” That is true for all 

reactions between metals and ligands in solution but there should 

be a different set of biotic ligand constants with copper for each 

organism. The way this paragraph is written may mislead the 

reader.

The reviewer is correct in that thermodynamic constants are 

properties of the metal and do not change in simulations with 

different organisms. While constants for reactions involving 

the biotic ligand may be different for different organisms, in 

the implementation of the BLM for development of the marine 

criteria for copper, they also do not change in the analysis 

used to prepare this document and the description is accurate 

as currently provided in the quoted text.

No edits 

needed.

Reviewer 3 A missing piece of information is related to the calculation of 

copper speciation. In saltwater, the ionic strength is 0.7 M. At 

such a high ionic strength, adjustment of binding constants is not 

straightforward. The commonly used empirical relations of 

Davies or Debye-Hückel cannot be used. How does the BLM 

account for ionic strength?

The text was modified to describe the ionic strength 

correction.

Section 2.4

Reviewer 4 The technical approach used to derive the draft copper criteria is 

logical and scientifically sound. The premise of the BLM and the 

input parameters are adequately explained. A limitation is that the 

criteria may not be adequately protective in tropical 

environments. The BLM uses a temperature of 22 0C and higher 

temperatures may increase copper bioaccumulation and toxicity 

to aquatic organisms. 

The BLM was developed to protective of species 

representative of those present in North American waters. 

Because temperature is one of the variables in the BLM, the 

model can be run with a temperature that is applicable to site 

conditions. The temperature of 220C was only used as a 

representative value. Text was added to clarify that the model 

allows input parameters, including temperature, to be adjusted 

to be applicable to site conditions. 

Reviewer 5 The MWQC-Cu relies heavily on the Environmental Security 

Technology Certification Program U.S. Department of Defense 

(ESTCP-DoD) study cited as:

The reference was updated to the final report. A hyperlink was 

added to facilitate access to this document.

Section 5.0
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Question 2 EPA Response

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Chadwick, D.B., I. Rivera-Duarte, P.F. Wang, G. Rosen, R. 

Santore, P. Paquin and A. Ryan. 2008. Demonstration of an 

integrated compliance model for predicting copper fate and 

effects in DoD Harbors, Environmental Security Technology 

Certification Program (ESTCP). Project ER-0523, Draft Final 

Technical Report, June 16, 2008. 

This citation should be updated to the “Final Report November 1, 

2008” as found at 

http://www.dtic.mil/dtic/tr/fulltext/u2/a499564.pdf if the authors 

view the modifications from the draft to the final report for 

Project ER-0523 to be not significant or substantial with regards 

to the application of this report and its seawater BLM parameters 

to the development of the MWQC-Cu. I could not locate the Draft 

Final Technical Report, June 16, 2008.

The Chadwick et al. (2008) project report does not appear to have 

made it into the peer-reviewed literature using my Web of 

Science searches for “Chadwick, D.B/author”, “copper biotic 

ligand model/topic” or “marine biotic ligand model/topic” or 

“seawater biotic ligand model/topic.” While this is unfortunate in 

the development of the MWQC-Cu, exemplified by descriptors in 

the report referring to “emerging” seawater BLM, I explored this 

reference in sufficient detail to support it as a primary and well-

executed scientific resource in the development of the MWQC-

Cu. The role and expertise of some of the Project ER-0523 report 

authors as the primary scientists responsible for the well-

established freshwater BLM science – which is a significant 

advancement in water quality risk management – lends significant 

support for application of the Project ER-0523 report as a key 

resource in support of the MWQC-Cu. In particular, the 

laboratory validation approaches cited as SERDP Projects ER-

1156 and ER-1157 in Chadwick et al. (2008) appear as significant 

bench validation of seawater Cu behavior in application the BLM. 
14

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 2 EPA Response

Revision 

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Document

As reported in Chadwick et al. (2008), the seawater BLM tested 

well against a rigorous set of model validation performance 

metrics. This effort coupled with the knowledge of an almost 

constant competing cation load and inorganic ligand load of 

seawater relative to freshwater, as illustrated in Figure 3, secures 

the high stability and adaptability of the BLM in a seawater 

application and thus in the development of the MWQC-Cu. Thus 

I conclude that the overall technical model approach of the 

seawater BLM – if there is concordance between the Draft Final 

Technical Report, June 16, 2008 as cited with the Final Report 

November 1, 2008 – is scientifically sound and supported. 

Reviewer 5 There are two recent papers by Deruytter, et al. that are not cited 

in the present draft report. The work:

Deruytter, D, et al. (2014) The Combined Effect of 

Dissolved Organic Carbon and Salinity on the 

Bioaccumulation of Copper in Marine Mussel Larvae

ENVIRONMENTAL SCIENCE & TECHNOLOGY

Volume: 48 Issue: 1 Pages: 698-705

DOI: 10.1021/es4024699

and 

Deruytter, D, et al. (2015) Salinity and dissolved organic 

carbon both affect copper toxicity in mussel larvae: 

Copper speciation or competition cannot explain 

everything

ENVIRONMENTAL TOXICOLOGY AND 

CHEMISTRY

Volume: 34 Issue: 6 Pages: 1330-1336

DOI: 10.1002/etc.2924

Deruytter, D, et al. (2015) appears to expand on the concerns of 

work published by de Polo and Scrimshaw (2012) that suggests 

incorporation of an osmotic gradient into the seawater BLM since 

the intestine can also be a biotic ligand. 

de Polo, A and Scrimshaw, MD (2012) Challenges for 

the development of a biotic ligand model predicting 

copper toxicity in estuaries and seas

The referenced papers were not cited because they were not 

available when the draft document was prepared. The 

citations have been added to the document.

Various 

locations.
15

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 2 EPA Response

Revision 

Location in 

Document

ENVIRONMENTAL TOXICOLOGY AND 

CHEMISTRY

Volume: 31 Issue: 2 Pages: 230-238

DOI: 10.1002/etc.1705

The primary driver of the MWQC-Cu is the work of Chadwick et 

al (2008), but because it never appeared in the primary peerreviewed literature, it is uncited in de Polo and Scrimshaw (2012) 

or Deruytter, D, et al. (2015). Figure 8 of the MWQC-Cu 

describing the Conceptual Model for Copper Effects on Aquatic 

Organisms shows gills and integument and thus appears to 

address some of the concerns of de Polo and Scrimshaw (2012). 

Coupled with the practical description of the well-supported 

salinity sensitivity of some Cu sensitive juvenile test species (e.g. 

Mytilus) discussed on page 21 there appears to be solid data to 

directly and briefly address the observations of de Polo and 

Scrimshaw (2012) and Deruytter, D, et al. (2015) within the 

MWQC-Cu draft report. In addition, the follow-up toxicodynamic 

work of de Polo, A, et al. (2014) may be very useful the MWQCCu Section 2.3, Overview of Copper Toxicity:

de Polo, A, et al. (2014) A New Role for Carbonic 

Anhydrase 2 in the Response of Fish to Copper and 

Osmotic Stress: Implications for Multi-Stressor Studies

PLOS ONE

Volume: 9 Issue: 10 Article Number: e107707

DOI: 10.1371/journal.pone.0107707

With the minor adjustments outlined above, the technical 

approach used to derive the draft copper criteria is logical, 

scientifically supported, and is consistent with the protection of 

estuarine/marine aquatic life from acute, chronic, and 

bioaccumulative effects.
16

2.3 CHARGE QUESTION 3(A)

3. (a) Please comment on the data used to derive the revised criteria, including data adequacy/ comprehensiveness, and the appropriateness of 

the data selected and/or excluded from the derivation of the draft criteria.

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 3(a) EPA Response

Revision 

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Document

Reviewer 1 The exclusion of dietary studies is unfortunate and does not 

reflect the current scientific understanding of metal toxicology. 

The exclusion of the Bielmyer papers is particularly without 

scientific justification. I understand the need to relate WQC to 

dissolved concentrations here, but the exposure concentration that 

the food is exposed to can be used as a descriptor of exposure. 

EPA’s failure to consider all exposure routes is very troubling. 

This would be analogous to setting a tolerance for a chemical

residue on a food but not considering drinking water as important 

in a human health hazard assessment. 

EPA concurs with the reviewer about the difficulty in 

characterizing dietary exposure and establishing critical tissue 

effects thresholds for bioaccumulated metals. 

Text has been added to discuss these points and incorporate 

the work of other researchers who discuss copper 

bioaccumulation and dietary exposure in detail and the 

uncertainties currently associated with its evaluation. In 

particular, text was added to detail how copper can 

bioaccumulate in aquatic organisms through multiple exposure 

routes including ingestion and direct exposure, and how total 

uptake depends on the copper concentration, exposure route 

and the duration of exposure.

Section 4.3.1 

(a new section)

Reviewer 2 The additional data used to generate the new criteria are sound 

and the approach transparent. Results are in line with what would 

be expected by simply examining the current data set.

Thank you for your comment. No edits 

needed.

Reviewer 3 Here the rationale for accepting /rejecting data is not provided. It 

might be useful to include an appendix to summarize how these 

decisions are made without having to dig up the report on this 

method.

Data selection is consistent with the procedures presented in 

the 1985 Guidelines, as indicated in the criteria document, and 

key components of the data selection process are discussed.

The 1985 Guidelines is generally available and EPA does not 

think it would be necessary to include the full document as 

part of the appendix. 

No edits 

needed.

Reviewer 3 One of the key parameters of the proposed copper BLM that 

influence the resulting values is the amount of dissolved organic 

carbon. I could not find a rationale for the use of the value of 1.3 

mg/L. There is only a reference to a footnote in appendix A. A 

sensitivity analysis would be useful for the reader to appreciate 

the influence of this parameter on the aquatic life criteria.

New reference conditions were selected and all toxicity data 

were re-normalized. 

The reference condition corresponds to values for pH, DOC, 

and salinity that are representative of some natural waters. 

These selected values are analogous to selecting a hardness of 

50 as a reference condition for freshwater metal criteria based 

on a hardness equation. The BLM is designed to allow users to 

Various 

locations.
17

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 3(a) EPA Response

Revision 

Location in 

Document

input and account for site-specific conditions, including a 

various dissolved organic carbon values, instead of adhering to 

a fixed set of site conditions. Text was added to clarify these 

points. 

Reviewer 3 It would be useful for the reader to get an idea of the uncertainty 

on the values given throughout the report. This could be done 

through several changes: i) provide uncertainty on data when 

available (for every mean values, a standard error can be 

computed); ii) perform error propagation calculations when 

possible, if not warn reader about the potential error; and iii) 

reduce the number of significant figures to two (I have seen many 

values with five significant figures; these mislead the reader to 

think that these values are very accurate).

There document describes several factors which serve to 

reduce and/or characterize uncertainty in the data. First, all 

studies are individually reviewed and evaluated to ensure they 

conform to standards of QA/QC and acceptability consistent 

with the 1985 Guidelines. Studies that were eliminated based 

on this analysis are summarized in Appendix F, along with the 

reason for their removal. Further, acceptable acute data were 

available for 84 species representing 58 taxonomic families, 

representing a robust database, helping to reduce uncertainty. 

Limited chronic data were available, so the more robust acute 

database was used with an acute-to-chronic ratio to derive the 

chronic value. Finally, Figure 15 provides a characterization 

of the variability of data used to derive the acute criteria with 

the depiction of 25th to 75th percentile ranges of these data.

Text was added that indicated intermediate calculations were 

performed to four significant figures to prevent rounding 

errors in subsequent revisions and that the number of digits 

does not reflect precision. Values were edited that had five 

significant figures. Final values are presented to two 

significant figures.

Section 2.8.3

Reviewer 4 The acute data used to derive the CMC are both adequate and 

comprehensive; however the chronic data are severely lacking, 

with data provided from only two animal species and no plant 

species. I do agree that criteria protective of animals should also 

theoretically be protective of plants, given that plants are 

generally more tolerant. That is a logical assumption. Even with 

the limited number of species in the chronic toxicity data set, the 

approach used to derive the CCC was logical and the CCC should 

be protective of most aquatic organisms.

Thank you for your comment. Based on limitations in the 

chronic data a robust acute-to-chronic ratio was derived using 

available data for two estuarine/marine species and data for 

five representative freshwater species, as described in Section 

3.6.2.

No edits 

needed.
18

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 3(a) EPA Response

Revision 

Location in 

Document

Reviewer 4 Tables are provided in appendices listing the unused data and the 

reasons for not using them. However, adding a list of the criteria 

necessary for data/studies to be included would be helpful (i.e., 

minimum number of animals, etc.). I do not think that I saw that 

in this document.

Data selection is consistent with the procedures presented in 

the 1985 Guidelines and key components of the data selection 

process are discussed in the criteria document. The 1985 

Guidelines is generally available and it is beyond the scope of 

the document to provide additional discussion of the criteria 

necessary for data to be included/excluded from the analysis.

No edits 

needed.

Reviewer 5 My review of MWQC-Cu Section 3 and Section 4 and the related 

report citations suggests a complete and comprehensive inclusion 

of the available peer-reviewed and published data validated for 

application to this purpose. For this review I did not access the 

individual papers to validate that the data was correctly used and 

transcribed in the context of the original citation. 

Thank you for your comment. No edits 

needed.
19

2.4 CHARGE QUESTION 3(B)

3. (b) Are there other relevant data that you are aware of that should be included? If so, please provide the criteria.

Reviewer

External Peer Reviewer Comments Regarding Charge 

Question 3(b) EPA Response

Revision 

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Document

Reviewer 1 Industry should support the generation of chronic tests that 

include the use of food that has been equilibrated with the 

identical aqueous test solutions used as the exposure water to the 

test animals. Only then will uncertainties about toxicity be 

alleviated. 

EPA agrees that generation of additional estuarine/marine 

chronic toxicity data for copper by the scientific community 

would be desirable.

No edits 

needed.

Reviewer 2 No. Thank you for your comment. No edits 

needed.

Reviewer 4 (See the answer to question #4). Thank you for your comment. No edits 

needed.

Reviewer 5 My search of the marine/seawater Cu toxicity literature found 

only one marine aquatic toxicity reference uncited in the MWQCCu draft document, Oliveira, et al. (2014). My brief assessment of 

the findings of this work suggest it would not change the criterion 

developed in the MWQC-Cu, however the authors may wish to 

confirm this and add this reference for completeness. 

Oliveira, BL (2014) Acute copper toxicity in juvenile fat 

snook Centropomus parallelus (Teleostei: 

Centropomidae) in sea water

NEOTROPICAL ICHTHYOLOGY

Volume: 12 Issue: 4 Pages: 845-852

DOI: 10.1590/1982-0224-20140040

Thank you for the additional study. The data for the species 

met acceptability criteria and was added to the acute dataset.

Various 

locations
20

2.5 CHARGE QUESTION 4

4. Are the derived criteria appropriately protective of listed species and commercially and recreationally important species?

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 4) EPA Response

Revision 

Location in 

Document

Reviewer 1 I think ignoring all exposure routes leads to uncertainty here. EPA concurs with the reviewer about the difficulty in 

characterizing dietary exposure and establishing critical tissue 

effects thresholds for bioaccumulated metals. 

Text has been added to discuss these points and incorporate 

the work of other researchers who discuss copper 

bioaccumulation and dietary exposure in detail and the 

uncertainties currently associated with its evaluation. In 

particular, text was added to detail how copper can 

bioaccumulate in aquatic organisms through multiple exposure 

routes including ingestion and direct exposure, and how total 

uptake depends on the copper concentration, exposure route 

and the duration of exposure.

Section 4.3.1 

(a new section)

Reviewer 2 In my opinion the derived criteria are appropriate, protective and 

scientifically defensible.

Thank you for your comment. No edits 

needed.

Reviewer 3 This question falls out of my area of expertise. However, the few 

commercially and recreationally important species are well 

identified in the report.

Thank you for your comment. No edits 

needed.

Reviewer 4 I think that the Bielmyer et al., 2010 paper (listed in the unused 

data table) should have been included because it presented 

chronic data about a sensitive tropical coral species that had been 

listed as threatened under the ESA. It was not included because 

the coral are symbiotic and contained algae housed in their coral 

exoskeleton. If the algae were separated from the coral, then the 

coral would be stressed, and toxicity data from those organisms 

would be skewed. Because symbiotic organisms are not included, 

they may not be protected by the copper CCC, particularly in 

tropical environments. This is another limitation of the chronic 

data set.

The Bielmyer et al. (2010) paper was reviewed and since the 

study methodology employed only three exposure 

concentrations per test, each would be classified as unused. 

However, the data are discussed as other data in support of the 

derived chronic criterion. 

Section 4.2
21

Reviewer External Peer Reviewer Comments Regarding Charge 

Question 4) EPA Response

Revision 

Location in 

Document

Reviewer 5 In my review of the draft report the MWQC-Cu, the derived 

criteria are appropriately protective of listed species and 

commercially and recreationally important species, by direct 

inclusion or extrapolation from published work. The authors have 

followed accepted pathways of aquatic ecosystem risk analysis 

and risk management, using best available knowledge and 

practices accepted in the major disciplinary areas overlapped in 

this complex challenge. In my view, the BLM has been 

satisfactorily adapted to seawater/marine environments within the 

generally accepted limitations of all modeling approaches. The 

MWQC-Cu draft report is honest about these limitations and the 

major MWQC-Cu citation of Chadwick et al. (2008) explicitly 

and exhaustively explores the practical and economic limitations 

of quantitative risk assessment/management and the advantages 

of using well vetted models in a complex scenario of dynamic 

variables, multiple stressors, and multiple receptors. In this regard 

the acute and chronic criteria developed are a major step forward 

in marine/estuarine management of copper. 

Thank you for your comment. No edits 

needed.
22

2.6 OTHER COMMENTS PROVIDED

Reviewer Other Comments EPA Response

Revision 

Location in 

Document

Reviewer 3 Other comments:

 Foreword, 1st paragraph: “copper” rather than 

“cadmium”.

The text was corrected as suggested. Foreword

Reviewer 3  Throughout the text there is an inconsistent use of: 

spacing before and after equal (=) signs; spacing 

between parentheses; e.g. “)(“ or “)_(“; “fresh water” 

and “freshwater”; “salt water” and “saltwater”.

Freshwater and/or fresh water use is grammatically correct. 

Parentheses were edited to be consistent.

Various 

locations

Reviewer 3  Acronyms missing on page xii: MDR; GMCV. MDR, GMCV and SMCV were added to the Acronym List Acronyms

Reviewer 3  P. 4: Not clear to me why “registration” and 

“reregistration” are both used.

These terms are consistent with the language FIFRA uses. No edits 

needed.

Reviewer 3  P. 11: “...which form of Cu+1 or Cu+2 is found...” OR 

“...which forms of Cu+1 or Cu+2 are found...”

The text was edited as, “...which forms of Cu+1 or Cu+2 are 

found.”

Section 2.2

Reviewer 3  P. 11: “...the free cupric (Cu2+) ion may be present”: 

the use of the word “may” suggests that this species 

may be absent which is physically impossible. All 

species are always present but these concentrations may 

be very low.

The text was edited as, “In oxic natural waters with neutral pH 

and above, the free cupric (Cu2+) ion is generally a minor 

species (Stumm and Morgan 1981).”

Section 2.2

Reviewer 3  P. 12, Figure 2: “forms” or “chemical species” instead 

of “strategy”?

The text was edited as, “chemical species.” Figure 2

Reviewer 3  P. 21: Check font size for “μ”. The text was revised as suggested. Section 2.4

Reviewer 3  P. 22, last line: Delete extra period. The text was revised as suggested. Section 2.5

Reviewer 3  P. 33: HCO3. The text was revised as suggested. Section 2.8.3
23

Reviewer Other Comments EPA Response

Revision 

Location in 

Document

Reviewer 3  P. 40, penultimate line: while alkalinity.

References cited:

[1] Morel FMM ed. 1983. Principles of Aquatic 

Chemistry. John Wiley & Sons, New York, NY, USA.

[2] Campbell PGC. 1995. Interactions between trace 

metals and aquatic organisms: A critique of the free-ion 

activity model. In Tessier A, Turner DR, eds, Metal 

Speciation and Bioavailability in Aquatic Systems. John 

Wiley & Sons, New York, NY, USA, pp 45-102.

The text was edited as, “...while salinity.” Section 3.3

Reviewer 4 Minor Comments:

Pg. 16 and Fig. 6: Delete blue outline around figures.

The text was revised as suggested. Figure 3

Figure 6

Reviewer 4 Pg. 22, last line: Delete the double period. The text was revised as suggested. Section 2.5

Reviewer 4 Pg. 26, Table 2: Change “cadmium” to “copper” The text was revised as suggested. Table 2

Reviewer 4 Pg. 32, 1st sentence: Delete “to” The text was revised as suggested. Section 2.8.2

Reviewer 4 Pg. 40, second to last line: Change “whilealinity” to “while 

salinity”

The text was revised as suggested. Section 3.3

Reviewer 4 Pg. 41, Table 8: Change the temperature to “22” instead of “2” The text was revised as suggested. Table 8

Reviewer 4 Table 9, 1st line: Delete the space after “FAV” before “:” The text was revised as suggested. Table 9

Reviewer 4 Fig. 11: Change “cadmium” to “copper” The text was revised as suggested. Figure 11

Reviewer 4 Appendix F: Delete “Unused” as it is redundant. The text was revised as suggested. Appendix F
24

3 REFERENCES CITED BY REVIEWERS

Bielmyer, G. K. and M. Grosell. 2011. Emerging issues in marine metal toxicity. Surface Chemistry, 

Bioavailability and Metal Homeostasis in Aquatic Organisms: An Integrated Approach. N. Bury and R. 

Handy. London (England), Kings College: 129-158.

Chadwick, D.B., I. Rivera-Duarte, P.F. Wang, G. Rosen, R. Santore, P. Paquin and A. Ryan. 2008. 

Demonstration of an integrated compliance model for predicting copper fate and effects in DoD Harbors, 

Environmental Security Technology Certification Program (ESTCP). Project ER-0523, Final Report 

November 1, 2008. Available online at: www.dtic.mil/dtic/tr/fulltext/u2/a499564.pdf.

de Polo, A. and M.D. Scrimshaw. 2012. Challenges for the development of a biotic ligand model predicting 

copper toxicity in estuaries and seas. Environ. Toxicol. Chem. 31(2): 230-238.

de Polo, A., L. Margiotta-Casaluci, A.E. Lockyer and M.D. Scrimshaw. 2014. A new role for carbonic 

anhydrase 2 in the response of fish to copper and osmotic stress: Implications for multi-stressor studies. PLOS 

ONE 9(10) Article Number: e107707.

Deruytter, D., J. Garrevoet, M.B. Vandegehuchte, E. Vergucht, B. De Samber, B. Vekemans, K. Appel, G. 

Falkenberg, K. Delbeke, R. Blust, K.A.C. De Schamphelaere, L. Vincze and C.R. Janssen. 2014. The 

combined effect of dissolved organic carbon and salinity on the bioaccumulation of copper in marine mussel 

larvae. Environ. Sci. Tech. 48(1): 698-705.

Deruytter, D., M.B. Vandegehuchte, J. Garrevoet, F. De Laender, E. Vergucht, K. Delbeke, R. Blust, K.A.C. 

De Schamphelaere, L. Vincze and C.R. Janssen. 2015. Salinity and dissolved organic carbon both affect 

copper toxicity in mussel larvae: Copper speciation or competition cannot explain everything. Environ. 

Toxicol. Chem. 34(6): 1330-1336.

Erickson, R.J. 2013. The biotic ligand model approach for addressing effects of exposure water chemistry on 

aquatic toxicity of metals: Genesis and challenges. Environ. Toxicol. Chem. 32(6): 1212-1214.

Jokela, W.E., J.P. Tilley and D.S. Ross. 2010. Manure nutrient content on Vermont dairy farms: Long-term 

trends and relationships. Comm. Soil Sci. Plant Anal. 41(5): 623-637.

Kiaune, L. and N. Singhasemanon. 2011. Pesticidal copper (I) oxide: Environmental fate and aquatic toxicity. 

D.M. Whitacre (Ed.). Rev. Environ. Contam. Toxicol. 213: 1-26.

Oliveira, B.L. 2014 Acute copper toxicity in juvenile fat snook Centropomus parallelus (Teleostei: 

Centropomidae) in sea water. Neotrop. Ichthyol. 12(4): 845-852.

Skrabal, S.A. J.R. Donat and D.J. Burdige. 2000. Pore water distributions of dissolved copper and coppercomplexing ligands in estuarine and coastal marine sediments. Geochimica Et Cosmochimica Acta. 64(11): 

1843-1857.

Thomas, K.V. and S. Brooks. 2010. The environmental fate and effects of antifouling paint biocides. Biofoul. 

26(1): 73-88.

Turner, A. 2010. Marine pollution from antifouling paint particles. Mar. Pollut. Bull. 60(2): 159-171.
25

U.S. EPA. 1998. Guidelines for ecological risk assessment. United States Environmental Protection 

Agency. Risk Assessment Forum. Office of Research and Development, Washington, D.C. 

EPA/630/R-95/002F.