Peer Review Report Task Order 68, Contract EP-C-12-029

TASK ORDER 68 UNDER

CONTRACT EP-C-12-029

PEER REVIEW OF THE DRAFT AQUATIC LIFE AMBIENT 

ESTUARINE/MARINE WATER QUALITY CRITERIA FOR COPPER

PEER REVIEW SUMMARY REPORT

January 4, 2016

Submitted to:

U.S. Environmental Protection Agency

Office of Water, Office of Science and Technology

Health and Ecological Criteria Division

1200 Pennsylvania Avenue, NW

Washington, DC 20460

Attn: Luis Cruz

Cruz.Luis@epa.gov

Submitted by:

Eastern Research Group, Inc.

110 Hartwell Avenue

Lexington, MA 02421
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CONTENTS

1.0 INTRODUCTION.............................................................................................................................. 1

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

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

2.0 SUMMARY OF REVIEWER COMMENTS ORGANIZED BY CHARGE QUESTION ..................................... 2

2.1 Please comment on the overall clarity of the document and construction as it relates 

to the derivation of each criterion. .............................................................................................. 2

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 

ffects? ........................................................................................................................................... 7

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..................................................................... 14

Are there other relevant data that you are aware of that should be included? If so, 

please provide the criteria. ........................................................................................................ 15

2.4 Are the derived criteria appropriately protective of listed species and commercially 

and recreationally important species?....................................................................................... 17

2.5 Other Comments Provided......................................................................................................... 19

3.0 NEW INFORMATION PROVIDED BY REVIEWERS .............................................................................21

APPENDIX A CHARGE TO REVIEWERS ...................................................................................................A-1

APPENDIX B INDIVIDUAL REVIEWER COMMENTS ................................................................................. B-1

Reviewer 1........................................................................................................................................................B-3

Reviewer 2........................................................................................................................................................B-9

Reviewer 3......................................................................................................................................................B-13

Reviewer 4......................................................................................................................................................B-19

Reviewer 5......................................................................................................................................................B-23
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1.0 INTRODUCTION

This report documents the results of an independent peer review of the Draft Aquatic Life Ambient 

Estuarine/Marine Water Quality Criteria for Copper, developed by the U.S. Environmental Protection Agency 

(EPA). Eastern Research Group, Inc. (ERG, a contractor to EPA) organized this review and developed this 

report. Sections 2.1 to 2.4 of this report present, for each charge question, the individual reviewer 

comments and a summary of those comments; Section 2.5 presents additional minor comments provided by 

two reviewers. New information (e.g., references) provided by reviewers is presented in Section 3.

Appendices A and B provide, respectively, the charge to reviewers and the complete set of comments 

submitted by each reviewer. 

1.1 Background

EPA’s Office of Water is charged with protecting ecological integrity and human health from adverse 

anthropogenic, water-mediated effects, under Section 304(a)(l) of the Clean Water Act. To reflect the latest 

scientific knowledge, the Agency has been working to update water quality criteria to protect aquatic life 

and aquatic-dependent wildlife from copper in estuarine/marine environments. 

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

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

copper criteria update utilizes 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. This differs from previous metals 

criteria which are based on empirical relationships between toxicity and water hardness. 

1.2 Peer Reviewers

ERG searched for, identified, and selected five reviewers who met technical selection criteria provided by 

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

• Gretchen K. Bielmyer-Fraser, Ph.D.; Associate Professor, Department of Biology, Valdosta State 

University.

• David Buchwalter, Ph.D.; Associate Professor, Department of Biological Sciences, North Carolina 

State University.

• Claude Fortin, Ph.D.; Researcher, INRS-Eau, Terre et Environnement.

• Stephen Klaine, Ph.D.; Professor and Director, Institute of Environmental Toxicology, Clemson 

University.

• Gregory Möller, Ph.D.; Professor of Environmental Chemistry and Toxicology, University of Idaho.

ERG provided reviewers with instructions, the review document (including appendices), the charge to 

reviewers (Appendix A of this report) prepared by EPA, and supplemental materials as described in the 

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

After receiving reviewer comments, ERG summarized reviewers’ responses to the charge questions, noting 

areas of agreement and disagreement, where relevant (see Section 2).
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2.0 SUMMARY OF REVIEWER COMMENTS ORGANIZED BY CHARGE QUESTION

This section presents summaries of reviewer comments organized by charge question. Each summary is 

followed by a table presenting the individual reviewer comments by charge question. Individual comments 

are copied directly from written comments as submitted by each reviewer and presented in Appendix B. 

2.1 Please comment on the overall clarity of the document and construction as it relates to the 

derivation of each criterion.

All reviewers found the document to be clear, and Reviewer 5 wrote that the draft document is 

comprehensive, accurate, persuasive, well written, and well organized. Reviewer 1, however, added that the 

Biotic Ligand Model (BLM) description section is “a bit” redundant and that the description of the final Acute 

to Chronic Ratio (ACR) derivation is “a bit” convoluted. 

Reviewer 2 commented that the document will be useful for those charged with regulating copper in marine 

and estuarine waters. The reviewer also noted that the Problem Formulation section is nicely laid out and 

describes the exposure scenarios well; the case study is a nice illustration and educational tool; Figure 5 is 

particularly useful; and the comparison between freshwater and marine scenarios is useful. Reviewer 4 

noted that the criteria derivation is clear. 

Reviewer 2 commented that a major drawback is that the BLM is an equilibrium model that does not allow 

for consideration of pulsed or episodic exposure with organ recovery. The reviewer clarified that this 

comment was not a criticism of the document, but rather a consideration for future research. Reviewer 3 

said that it is difficult to appreciate the rigor of the approach without access to some of the cited references, 

and suggested that an appendix be added. Reviewer 3 also said that the use of the term “bioavailable” is not 

always correct (because of the dynamic nature of metal binding, one cannot say that a particular metal 

species is not bioavailable), and suggested removing Section 2.5 because it is superfluous. 

Reviewer 3 commented that Figures 4 through 7 are missing information that would allow the reader to 

understand them. This reviewer also noted that Figure 11 is not very useful with only two values and that its 

y-axis label should read copper instead of cadmium. Reviewer 4 had some questions about Figures 4 and 5

and noted that the discussion about these figures is confusing. 

Reviewer 5 commented that the cited references represent major works in the related fields and, overall, 

are supportive of the draft document. The reviewer made several suggestions: 

• Review the final version of Chadwick et al. (2008) and update the reference accordingly. 

• In Section 2.1, broaden the discussion to include copper sulfate use in dairy cattle footbaths, an 

emerging source of copper release to the environment (see the referenced Agricultural Extension 

publication1 and Jokela et al., 20102). 

• Include the reviews by Turner (2010)3, Thomas and Brooks (2010)4, and Kiaune and Singhasemanon 

(2011)5 in the development of the environmental fate and transport of marine copper. 

 

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

2 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.

3 Turner, A. 2010. Marine pollution from antifouling paint particles. Marine Pollution Bulletin. Volume: 60 Issue: 2 

Pages: 159-171.
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• Include a short comment about marine sediment copper geochemistry (e.g., Skrabal et al., 20006) in 

Section 2.2.

• Add Erickson (2013)7 (a significant review reference describing BLM strengths and cautionary 

weaknesses) to the discussions in Sections 2.4 and 3.8.3.

Reviewer Comments EPA Response to Comments

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). 

The language regarding the derivation of the final Acute to 

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

values.

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.

Problem formulation. Well done, nicely laid out and exposure 

scenarios described well.

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. 

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.

How does the varying salinity in estuaries pose special 

challenges?

Given the obvious mechanism of phytotoxicity for copper, it is 

 4 Thomas, KV and Brooks, S. 2010. The environmental fate and effects of antifouling paint biocides. Biofouling. Volume: 

26 Issue: 1 Pages: 73-88.

5 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.

6 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.

7 Erickson. 2013. 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.
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Reviewer Comments EPA Response to Comments

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.

Reviewer 3 a) 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.

b) 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.

c) 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.

d) Section 2.5 (pp. 22-24) seems superfluous. Consider 

removing.

e) P. 40, middle: “Application of the BLM may reduce, if not 
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Reviewer Comments EPA Response to Comments

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.

f) P. 11. Last paragraph is incomplete and incoherent but I 

was instructed to ignore this paragraph.

g) 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.

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.

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

confusing the way it’s presented.

Fig. 4: Define “(N)” and “(S)”.

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

model representation”.

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 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. 

The Introduction provides overall sufficient background for 
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Reviewer Comments EPA Response to Comments

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

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

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
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Reviewer Comments EPA Response to Comments

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

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.

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?

Reviewers 2, 3, 4, and 5 commented that the technical approach is sound. Reviewer 2 added that it is 

consistent with previous BLM efforts, as well as established methodology for developing water quality 

criteria. The reviewer noted that the results are sound and scientifically defensible even though short on 

chronic data. Reviewer 3 said that the use of the BLM is an improvement over the use of empirical hardness 

relationships. The reviewer added that there should be a different set of biotic ligand constants with copper 

for each organism and that ionic strength is missing from the calculation of copper speciation. Reviewer 4 

noted that higher temperatures may increase copper bioaccumulation and toxicity to aquatic organisms; 

therefore, the criteria may not be adequately protective in tropical environments. Reviewer 5 concluded 

that, with minor adjustments, the technical approach is logical, scientifically supported, and consistent with 
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the protection of estuarine/marine aquatic life from acute, chronic and bioaccumulative effects. The 

reviewer suggested that EPA briefly address the observations of de Polo and Scrimshaw (2012)8 and 

Deruytter et al. (2015)9 in the report and consider including the toxicodynamic work of de Polo et al. 

(2014)10 in Section 2.3. Reviewer 5 also noted that Chadwick et al. (2008) is now final (see 

http://www.dtic.mil/dtic/tr/fulltext/u2/a499564.pdf).

Reviewer 1 was concerned that the draft document ignored a lot of credible science and, therefore, that the 

proposed water quality criteria were based on only a portion of current scientific understanding. In 

particular, the reviewer described both the toxicity overview and the document’s treatment of 

bioaccumulative effects as substantially inadequate. Regarding bioaccumulation, EPA only acknowledges the 

potential for copper toxicity via dissolved exposures, which is incomplete because dietary bioaccumulative 

effects are well documented in the literature and the literature also shows that copper toxicity can result 

from dietary exposures. The reviewer recommended that EPA use (1) the dissolved concentrations the diet 

was exposed to as an exposure descriptor, and (2) the BLM to better understand exposures via water and 

ingestion. This reviewer also was very uncomfortable with the language, on page 33, about the stability of 

marine waters and its application to estuarine waters, which are less stable. 

Reviewer Comments EPA Response to Comments

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.)

 8 de Polo, A and Scrimshaw, MD. 2012. Challenges for the development of a biotic ligand model predicting copper 

toxicity in estuaries and seas. Environmental Toxicology and Chemistry. Volume: 31 Issue: 2 Pages: 230-238.

9 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.

10 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.
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Reviewer Comments EPA Response to Comments

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 pro-oxidant. 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.

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. 

P. 12: Figure 2 is not particularly informative. 

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. 

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.

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

in complexation reactions be portrayed here?

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

toxicity is expressed here. 

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 
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Reviewer Comments EPA Response to Comments

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. 

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).

P. 31: section 2.8.2 check grammar of first sentence.

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).

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

to describe an LC50.

P. 38: What is a 96 hour static multi-generational test?

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? 

P. 41 Table 8: I assume the 2°C is a typo?

P. 46 Figure 11: check Y axis label. This is a copper 

criterion not a cadmium criterion. 

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?

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 by the reader. While a little 

short on chronic data, the results are sound and 

scientifically defensible.
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Reviewer Comments EPA Response to Comments

Reviewer 3 a) 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. 

b) 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.

c) 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?

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 0

C and higher temperatures 

may increase copper bioaccumulation and toxicity to 

aquatic organisms.

Reviewer 5 The MWQC-Cu relies heavily on the Environmental 

Security Technology Certification Program U.S. 

Department of Defense (ESTCP-DoD) study cited as:

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 
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Reviewer Comments EPA Response to Comments

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. 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. 
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Reviewer Comments EPA Response to Comments

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

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 peer-reviewed 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 wellsupported 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 MWQCCu draft report. In addition, the follow-up toxicodynamic 
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Reviewer Comments EPA Response to Comments

work of de Polo, A, et al. (2014) may be very useful the 

MWQC-Cu 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. 

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. 

Reviewer 2 thought that the data used to generate the new criteria were sound, the approach was 

transparent, and the results were in line with what would be expected from examining current data. 

Reviewer 5 commented that the peer-reviewed and published data included in the report were complete 

and comprehensive.

Reviewer 1 reiterated that excluding dietary studies was unfortunate and troubling, and repeated the 

recommendation that EPA use the exposure concentration the food is exposed to as an exposure descriptor. 

Reviewer 3 could not find a rationale for the use of 1.3 mg/L as the amount of dissolved organic carbon. This 

reviewer recommended that EPA include a sensitivity analysis to better understand the influence this 

parameter has on the aquatic life criteria. Reviewer 1 also suggested that EPA provide information on 

uncertainty of the data when that information is available, perform error propagation calculations when 

possible, and reduce the number of significant figures to two. 

Reviewer 3 commented that the rationale for accepting/rejecting data was not provided and suggested 

including an appendix to summarize the decision criteria. Reviewer 4 also commented that including a list of 

criteria for data inclusion would be helpful.

Reviewer 4 thought that the acute data used to derive the criterion maximum concentration (CMC) were 

adequate and comprehensive; however, the chronic data were severely lacking. Even so, this reviewer said 

that the approach used to derive the criterion continuous concentration (CCC) was logical and that the CCC 

should be protective of most aquatic organisms. 
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(b) Are there other relevant data that you are aware of that should be included? If so, 

please provide the criteria.

Reviewers 1 and 4 both disagreed with excluding Bielmyer’s work from the report. Reviewer 1 commented 

that, to alleviate the uncertainties about toxicity, industry should support the generation of chronic tests 

that include the use of food that has been equilibrated with the identical aqueous solutions used as the 

exposure water to the test animals. Reviewer 5 suggested including the findings from Oliveira et al. (2014).11

Reviewers 2 and 3 did not suggest additional data. 

Reviewer Comments EPA Response to Comments

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.

Are there other relevant data that you are aware of that 

should be included? If so, please provide the criteria.

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.

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.

Are there other relevant data that you are aware of that 

should be included? If so, please provide the criteria.

No.

 11 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.
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Reviewer Comments EPA Response to Comments

Reviewer 3 a) 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.

b) 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.

c) 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).

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.

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.
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Reviewer Comments EPA Response to Comments

Are there other relevant data that you are aware of that 

should be included? If so, please provide the criteria. 

(See the answer to question #4).

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. 

Are there other relevant data that you are aware of that 

should be included? If so, please provide the criteria.

My search of the marine/seawater Cu toxicity literature 

found only one marine aquatic toxicity reference uncited 

in the MWQC-Cu 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

2.4 Are the derived criteria appropriately protective of listed species and commercially and 

recreationally important species?

Reviewer 2 commented that the derived criteria are appropriate, protective, and scientifically defensible. 

Reviewer 5 said that the acute and chronic criteria are a major step forward in marine/estuarine 

management of copper, and noted that the derived criteria are appropriately protective of listed species 

and commercially and recreationally important species. Reviewer 5 commented that the authors followed 

accepted pathways of aquatic ecosystem risk analysis and risk management using best available knowledge 

and practices, and were honest about the limitations inherent with all modeling approaches. 

Reviewer 1 responded that EPA’s failure to consider all exposure routes leads to uncertainty about whether 

the criteria are protective. Reviewer 4 pointed out that because symbiotic organisms were not included, 

they may not be protected by the copper CCC, particularly in tropical environments. 
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Reviewer 3 did not respond because this question was outside the reviewer’s area of expertise, but noted 

that the few commercially and recreationally important species were well identified in the report. 

Reviewer Comments EPA Response to Comments

Reviewer 1 I think ignoring all exposure routes leads to uncertainty 

here.

Reviewer 2 In my opinion the derived criteria are appropriate, 

protective and scientifically defensible.

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.

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.

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 
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Reviewer Comments EPA Response to Comments

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.

2.5 Other Comments Provided

Reviewer Comments EPA Response to Comments

Reviewer 3 Other comments:

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

“cadmium”.

• 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”.

• Acronyms missing on page xii: MDR; GMCV.

• P. 4: Not clear to me why “registration” and 

“reregistration” are both used.

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

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

• 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.

• P. 12, Figure 2: “forms” or “chemical species” instead 

of “strategy”?

• P. 21: Check font size for “μ”.

• P. 22, last line: Delete extra period.

• P. 33: HCO3.

• P. 40, penultimate line: while alkalinity.

References cited:

[1] Morel FMM ed. 1983. Principles of Aquatic Chemistry. 
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Reviewer Comments EPA Response to Comments

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

[2] Campbell PGC. 1995. Interactions between trace 

metals and aquatic organisms: A critique of the freeion 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.

Reviewer 4 Minor Comments:

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

Pg. 22, last line: Delete the double period.

Pg. 26, Table 2: Change “cadmium” to “copper”

Pg. 32, 1st sentence: Delete “to”

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

salinity”

Pg. 41, Table 8: Change the temperature to “22” instead 

of “2”

Table 9, 1st line: Delete the space after “FAV” before “:”

Fig. 11: Change “cadmium” to “copper”

Appendix F: Delete “Unused” as it is redundant.
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3.0 NEW INFORMATION PROVIDED BY REVIEWERS

This section presents all new information that reviewers provided in addition to or within their specific 

responses (presented in Section 2, above) to the charge questions. 

Reviewer New Information Provided EPA Response to Comments 

Reviewer 1 Bielmeyer and Grosell, Chapter 5: Emerging issue in 

marine metal toxicity.

Reviewer 5 Question 1

Agricultural Extension publication: 

http://articles.extension.org/pages/22177/coppersulfate-foot-baths-on-dairies-and-crop-toxicities

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

Turner, A (2010) Marine pollution from antifouling 

paint particles

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

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

Skrabal, SA et al. (2000) Pore water distributions of 
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Reviewer New Information Provided EPA Response to Comments

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

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

Question 2

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

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

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

the development of a biotic ligand model predicting 

copper toxicity in estuaries and seas

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

Volume: 31 Issue: 2 Pages: 230-238

DOI: 10.1002/etc.1705

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
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Reviewer New Information Provided EPA Response to Comments 

Question 3

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
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APPENDIX A 

CHARGE TO REVIEWERS
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Technical Charge to External Peer Reviewers

Contract No. EP-C-12-029

Task Order 68

November 2015

External Letter Peer Review of EPA’s Draft Aquatic Life Ambient 

Estuarine/Marine Water Quality Criteria for Copper

BACKGROUND

The U.S. Environmental Protection Agency (EPA) Office of Water is charged with protecting ecological 

integrity and human health from adverse anthropogenic, water-mediated effects, under the purview of the 

Clean Water Act (CWA). In support of this mission, EPA is working to update water quality criteria to protect 

aquatic life and aquatic-dependent wildlife from the presence of copper in estuarine/marine environments.

EPA’s document presents draft acute and chronic criteria expressed as concentrations of copper in 

estuarine/marine waters (dissolved). Criteria for copper were last updated in 2007. The 2007 release only 

updated freshwater criteria and differed from EPA’s previous metals criteria primarily based on how metal 

availability to organisms is addressed with use of the biotic ligand model (BLM). 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, and 

differs from previous metals criteria which are based on empirical relationships between toxicity and water 

hardness. The 2015 copper criteria update utilizes the recently-developed marine BLM to provide updated 

acute and chronic water quality criteria for copper in estuarine/marine waters.

CHARGE QUESTIONS

The draft document provided is the focus of this review. Model files have been provided to reviewers as 

supplemental information only and it is not required to run the model or review these files (at your 

discretion). 

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?

3. 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.

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?
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APPENDIX B 

INDIVIDUAL REVIEWER COMMENTS
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COMMENTS SUBMITTED BY 

Reviewer 1
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External Letter Peer Review of EPA’s Draft Aquatic Life Ambient 

Estuarine/Marine Water Quality Criteria for Copper

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

of each criterion.

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). 

The language regarding the derivation of the final Acute to Chronic Ratio (ACR) is a bit convoluted in the use 

of freshwater values. 

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?

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.)

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 pro-oxidant. 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. 

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.

P. 12: Figure 2 is not particularly informative.
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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.

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.

P. 16 Figure 3: Shouldn’t the anions and their importance in complexation reactions be portrayed here?

P. 16: Again, the overly simplistic and incomplete view of toxicity is expressed here.

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.

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).

P. 31: section 2.8.2 check grammar of first sentence.

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). 

P. 34. I’m not sure about the use of the term “threshold” to describe an LC50.

P. 38: What is a 96 hour static multi-generational test?

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?

P. 41 Table 8: I assume the 2°C is a typo?

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

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?

3. 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.

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 
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B-7

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. 

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

criteria.

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. 

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

important species?

I think ignoring all exposure routes leads to uncertainty here. 
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COMMENTS SUBMITTED BY

Reviewer 2
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External Letter Peer Review of EPA’s Draft Aquatic Life Ambient 

Estuarine/Marine Water Quality Criteria for Copper

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

of each criterion.

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.

Problem formulation. Well done, nicely laid out and exposure scenarios described well.

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. 

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.

How does the varying salinity in estuaries pose special challenges?

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.

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?

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

and scientifically defensible.

3. 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.

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.

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

criteria.

No.
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4. Are the derived criteria appropriately protective of listed species and commercially and recreationally

important species?

In my opinion the derived criteria are appropriate, protective and scientifically defensible.
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COMMENTS SUBMITTED BY 

Reviewer 3
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B-15

External Letter Peer Review of EPA’s Draft Aquatic Life Ambient 

Estuarine/Marine Water Quality Criteria for Copper

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

of each criterion.

a) 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.

b) 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.

c) 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.

d) Section 2.5 (pp. 22-24) seems superfluous. Consider removing.

e) 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.
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f) P. 11. Last paragraph is incomplete and incoherent but I was instructed to ignore this paragraph.

g) P. 46, Figure 11: I am not convinced this figure is useful with only two values. Note also that the yaxis label should read copper and not cadmium.

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?

a) 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.

b) 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.

c) 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?

3. 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. Are there other relevant data that you are aware of that should be

included? If so, please provide the criteria.

a) 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.

b) 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.

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

important species?

This question falls out of my area of expertise. However, the few commercially and recreationally important 

species are well identified in the report.

Other comments:

• Foreword, 1st paragraph: “copper” rather than “cadmium”.

• 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”.

• Acronyms missing on page xii: MDR; GMCV.

• P. 4: Not clear to me why “registration” and “reregistration” are both used.

• P. 11: “...which form of Cu+1 or Cu+2 is found...” OR “...which forms of Cu+1 or Cu+2 are found...”

• 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 there concentrations

may be very low.

• P. 12, Figure 2: “forms” or “chemical species” instead of “strategy”?

• P. 21: Check font size for “μ”.

• P. 22, last line: Delete extra period.

• P. 33: HCO3.

• 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 freeion 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.
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COMMENTS SUBMITTED BY 

Reviewer 4
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Peer Review Report Task Order 68, Contract EP-C-12-029 

B-21

External Letter Peer Review of EPA’s Draft Aquatic Life Ambient 

Estuarine/Marine Water Quality Criteria for Copper

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

of each criterion.

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. 

Pgs. 17-18: The discussion about Figs 4 and 5 is a little confusing the way it’s presented.

Fig. 4: Define “(N)” and “(S)”.

Fig. 5: Where is the “convergence”? Please clarify the “single model representation”.

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?

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 0

C and higher 

temperatures may increase copper bioaccumulation and toxicity to aquatic organisms. 

3. 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.

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.

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. 

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

criteria. 

(See the answer to question #4.) 
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4. Are the derived criteria appropriately protective of listed species and commercially and recreationally

important species?

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.

Minor Comments:

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

Pg. 22, last line: Delete the double period.

Pg. 26, Table 2: Change “cadmium” to “copper”

Pg. 32, 1st sentence: Delete “to”

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

Pg. 41, Table 8: Change the temperature to “22” instead of “2”

Table 9, 1st line: Delete the space after “FAV” before “:”

Fig. 11: Change “cadmium” to “copper”

Appendix F: Delete “Unused” as it is redundant.
Peer Review Report Task Order 68, Contract EP-C-12-029 

B-23

COMMENTS SUBMITTED BY 

Reviewer 5
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Peer Review Report Task Order 68, Contract EP-C-12-029 

B-25

External Letter Peer Review of EPA’s Draft Aquatic Life Ambient 

Estuarine/Marine Water Quality Criteria for Copper

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

derivation of each criterion.

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 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. 

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-foot-baths-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

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

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
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B-26

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

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

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.

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?

The MWQC-Cu relies heavily on the Environmental Security Technology Certification Program U.S. 

Department of Defense (ESTCP-DoD) study cited as:

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 
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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. 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 MWQCCu. 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. 

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

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

Volume: 31 Issue: 2 Pages: 230-238

DOI: 10.1002/etc.1705
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The primary driver of the MWQC-Cu is the work of Chadwick et al (2008), but because it never appeared in 

the primary peer-reviewed 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 MWQC-Cu 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. 

3. 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.

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. 

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

criteria.

My search of the marine/seawater Cu toxicity literature found only one marine aquatic toxicity reference 

uncited in the MWQC-Cu 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
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4. Are the derived criteria appropriately protective of listed species and commercially and recreationally

important species?

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.