## Response t o Comments from External Peer Review of the “Technical Review of Ethylene Glycol Mono

- Butyl Ether (EGBE)”

September 2009

Environmental Analysis Division Office of Information Analysis and Access Office of Environmental Information U.S. En vironmental Protection Agency 1200 Pennsylvania Avenue, NW Washington, DC 20460Page 2 of 17 

## Peer

- Review Comments and Responses on

Technical Review of Ethylene Glycol Mono

- Butyl Ether (EGBE)

Charge to Peer Reviewers
EPA has prepared a technical review document to assess the chemistry, environmental fate, and the potential environmental impacts associated with releases of and exposures to EGBE. The purpose of this peer review is to seek comment on the accuracy and completeness of EPA’s assessment.

Peer Review Questions :

Chemistry and Fate
1. Are there any other chemical properties of EGBE that should be included?

2. Does the technical review accurately address the fate of EGBE in the envi ronment including transformations resulting in the formation of toxic chemicals?

Environmental Effects 1. Does the summary statement and review of the literature present a clear rationale and accurately reflect the conclusions regarding the ecological h azards of EGBE?

1. CHEMISTRY AND FATE

Comment 1

- 1 : The Technical Review summarizes the salient properties of EGBE. While there are other properties that can be identified (e.g., surface tension), I don’t believe they are germane to the subject of
this review. The EU risk assessment cited above identifies a somewhat high vapor pressure value (1.41) vs. the Dow Chemical value of 0.88 used in the review. Probably a more important difference is Henry’s
Constant. The Technical Review identifies 1.6  10

- 6 as Henry’s Constant based on Johanson and Dynesius (1988). Kim et al. (2001) using two different experimental methods reported a value of 0.082
Pa.m 3 /mol or 0.82  10

- 6 atm m 3 /mol. This value is roughly half that used in the Technical Review. The EU report n otes that direct measurement of Henry’s Law Constant is preferable for water miscible compounds such as EGBE. EPA should consider this information. It will not change the overall
conclusions of EPA’s review.Page 3 of 17

Kim, B. R., E. M. Kalis, T. DeWulf and K. M. An drews (2000). "Henry's law constants for paint solvents and their implications on volatile organic compound emissions from automotive painting." Water Environment Research 72(1): 65

- 74. (peer reviewer 1 )

EPA Response: The Henry’s law constant value cite d in the Technical R eview has been replaced with
the value of 8.16×10

- 7 atm

- m 3 /mol at 25°C from Kim et al. (2000).

Comment 1

- 2 : The physical, chemical and biological processes influencing EGBE environmental fate are well described and for the most part q uantified. Additional information that would help give the reader a better idea of the environmental behavior of EGBE would be details on how it gets into the environment. While uses are described in section 1.5 no discussion of how the material gets into the environment is given. This is important because if the environmental processing data are exhaustive, the discussion in section 1.6.4 should provide the reader with where in the environment the risk of effects is greatest. This discussion concludes w ith the results of an equilibrium distribution model suggesting that the majority of the EGBE would be on the land surface and in the water. If for example, the primary route of EGBE entry into the environment is through wastewater release (not really lik ely since 96% of EGBE is degraded in sewage sludge after 14 days) the results of this generalize d modeling would be
irrelevant. (peer reviewer 2 )

EPA Response: Specific information regarding the release of EGBE into the environment has not been
located in the available literature. Emission inputs used for the new fugacity calculation in Section 1.6.4 are based on TRI data for the “certain glycol ethers” category as provided on page 2 of the assessment

. The assumption that the release data reported for this category are representative of EGBE releases is also
noted.

Comment 1

- 3: Another apparent inconsistency is the discussion in section of 1.6.1 discussing the slow
volatilization of EGBE from moist soil and water surfaces with the discussion of toxic transformation product formation in section 1.6.5. If the reader is to believe the information from section 1.6.1 and the resulting model predictions of section 1.6.4 that says that less than 3% of EGBE will be found in the atmosphere, why the emphasis on toxic transformation product formation in the atmosphere in section
1.6.5? (peer reviewer 2 )

EPA Response: The EPIWIN fugacity model predictions have been revised based on the use of actual environmental release values reported to EPA by industry in r esponse to the TRI Program. The revisedPage 4 of 17

environmental distribution values indicate that the atmosphere will be a significant sink (47%) for released EGBE. Based upon this revision, the emphasis on atmospheric transformation products in the report will re main.

Comment 1

- 4 : Other questions that come to mind as I read the document include the following:
1. Does the indirect photooxidation of EGBE occur on m o ist soil surfaces?
2. Does photoxidation occur in surface waters that contain natural organic matter (N OM)? NOM has been shown to mediate oxidation in aquatic systems. (peer reviewer 2 )

EPA Response: Information regarding indirect photooxidation of EGBE on moist soil surfaces and photooxidation in surface waters containing neutral organic matter was not located in the available
literature.

Comment 1

- 5 : Considering the high water solubility of EGBE and fugacity models, the major sink for this compound is aquatic ecosystems, especially water. This compound is expected to be dissociated in water dependin g on the pH of the water and the dissociated forms are expected to have environmental fate
different from the neutral form. Acid

- dissociation constant (pKa) provides information regarding this property. It will be useful and important to report pKa of EG BE. ( peer reviewer 3 )
EPA Response: Acid

- dissociation constant (pKa) is not relevant for EGBE. EGBE does not contain any functional groups that will dissociate under environmental conditions.

Comment 1

- 6 : All the relevant properties are included. The re is some ambiguity about the solubility in water. It is given as “infinite” in Table 1.1 but as 1 x 10 6 mg/L in Table 2.1. In reality the later figure is the density of water and is used as a “dummy value” in the EPIWIN program. It would be better to have
one Table and with SI units. ( peer reviewer 4 )

EPA Response: Table 2.1 has been removed from the document. The units used in Table 1.1 are commonly used and accepted units. For the sake of clarity, SI units will not be added to the table.

Commen t 1

- 7 : The Review accurately addresses the fate of EGBE. According to the EU risk assessment, the theoretical distribution of EGBE is even more concentrated in water than that reported in EPA’s Review (99 vs. 41.7%). Obviously, different models were used and Henry’s Law Constant is higher in the EU model (although all other model inputs were apparently the same). While this disparityPage 5 of 17

does not drastically alter interpretations in EPA’s Review, this analysis should perhaps be checked. ( peer reviewer 1 )

EPA Response: The fugacity calculation has been performed again using a different Henry’s law constant (8.16×10

- 7 atm

- m 3 /mol at 25°C from Kim et al. (2000)), a different Koc value (7.6), and different emission input values ( 8 2 % to air, 8 % to water, 7 % to soi l, and 0% to sediment). The emission inputs
were chosen based on the TRI data for the “ce rtain glycol ethers” category, with the as sum ption that reported releases for this category are representative of EGBE releases. These changes result in partitioning values of 2 0 % to air, 33 % to water, 47 % to soil, and 0% to sediment. The inputs used for this calculation are similar to those used for the EU risk assessment fugacity calculation. The major
difference is that the EU assessment used a Level I model where as a Level III model was used for this assessment. The Level III fugacity model is considered to be more appropriate than the Level I model for
the purposes of this Technical R eview assessment.

Comment 1

- 8 : The review discusses transport, degradation, t ransformation, and distribution of EGBE in the environment. While the major topics related to environmental fate of EGBE have been covered, there is no information on the fate of EGBE in terrestrial and aquatic environments . For example, atmospheric
fate , degradation, and transformation products in the atmosphere have been discussed. However, fate of this compound in the terrestrial environment (soil) and aquatic environment are not addressed. What are the degradation products in soil and water? What i s the half

- life in soils and water? What is the fate of the degradation products in soil and water? Are the degradation products toxic? This information is especially important because fugacity models have shown that the environmental sink for EGBE is water and soil. ( peer reviewer 3 )

EPA Response: Very limited i nformation regarding actual residence times of EGBE in soil and water
has been located in the available literature. One study has been located that indicates that butoxyacetic acid is a prod uct of EGBE biodegradation. This information will be included in Section 1.6.5 along with a brief description of the toxicity of this product. Information regarding the fate of butoxyacetic acid in
the environment is not readily available.

Comment 1

- 9: Degradation and metabolism in biota (e.g. fish or rat or any rodent models) is not discussed. The reviewer has searched the literature and found out that the biological metabolism of EGBE can lead to the formation of butoxy acetic acid and this compound is hemolytic. In addition glycolic acid (which is nephrotoxic) and several toxic metabolites are formed in animals. It is importantPage 6 of 17

to discuss the biological fate of EGBE including transformation products and toxicity? The study of Price
et al. 1974 is t oo old to draw any reliable conclusion. ( peer reviewer 3 )

EPA Response: Information about the biological transformation of EGBE to 2

- butoxyacetic acid was
added to Section 1.6.5. Toxic Transformation Products. Detailed discussion about the toxicity of transformation products is beyond the scope of this assessment. Regarding the comment about the Price et al. (1974) study, the study has value despite its age, and therefore it remains in the assessment.

Comment 1

- 10 : It is important to indicate the ma jor pathways of EGBE released into the environment (section 1.4, lines 16

- 17) i.e., mention whether the major release is through air or water or soil? Such information may be available from TSRI (toxic substances release inventory). This would dictate t he reliability of fate assessment for any chemical released into the environment. ( peer reviewer 3 )

EPA Response: Specific information regarding the release of EGBE into the environment has not been located. EPA’s toxics release inventory (TRI) contain s data for the “certain glycol ethers” category of
which EGBE is a member
, but it does not contain data for EGBE specifically

. The following paragraph in section 1.1 is revised in an effort to clarify TRI release information reported relevant to EGBE:

“ 

### In 200 7 , releases of glycol ethers reported to the Toxic Release Inventory (TRI) (U.S. EPA, 200 9 ) under the “certain glycol ethers” category totaled approximately 18,476,000 pounds. Reported releases to air, surface water, and land were approximately 16, 416,000, 87,000, and 1,311,000 pounds, respectively. Approximately 126,000 pounds were released via underground injection. Approximately 7,902,000 pounds were transferred to publicly

- owned treatment works (POTWs). EGBE is one of the glycol ethers repor table under the “certain glycol ethers” category (specific release informa tion for EGBE is not available in the TRI database). It is not known how much of these amounts are attributable to EGBE releases; however, this may be a large percentage since EGBE is the single most widely produced glycol ether (Dow, 2006). ”

Comment 1

- 11: Several of the literature surveyed for this review is based on industry sponsored
research and some bias has been introduced. ( peer reviewer 3 )

EPA Response: See response to comment 3

- 15 below

.

Comment 1

- 12 : For any of the above comments, if the authors think that there is no information in the literature (for smog/groundwater problem/biological fate/degradation in soil/water), it should be mentioned accordingly, in summary

. ( peer reviewer 3 )Page 7 of 17

EPA Response: Statements indicating that relevant data have not been located in the available literature
have been included in the Technical R eview text where appropriate.

2. ENVIRONMENTAL EFFECTS

Comment 2

- 1: The EU risk assessm ent reports a valid chronic (21d) EC 20 = 175 mg/L (INERIS, 1999). INERIS (1999d). Détermination de la toxicité chronique du 2

- butoxyethanol vis

- à

- vis de Daphnia Magna , Ba746a

- CGR21427. Verneuil

- en

- Halatte, France, 15 décembre 1999, INERIS: 13. ( peer revi ewer 1 )

EPA Response: Because “INERIS (1999)” is an unpublished report, EPA was unable to obtain it.
Instead the EC 50 value, which is more stan dard than an EC 20 , are reported and cited as being from “INERIS (1999), as cited in the EU Risk Assessment Rep ort on EGBE.”

Comment 2

- 2: Given this chronic value, one can compute an acute:chronic ratio (ACR) = 1815 (48h
EC 50 )/175 or approximately 10. This ACR is fairly moderate also suggesting that EGBE is unlikely to elicit high long

- term toxicity. ( peer revi ewer 1 )

EPA Response: No further action was taken since the ACR supports the available experimental and predicted chronic values already included in the assessment.

Comment 2

- 3: Note that the EU Report cites valid freshwater fish acute data for rainbow trout and fathead minnow. This report also cites valid acute data for the freshwater invertebrate Brachionus calcyiflorus using a method identical to the approved ASTM standard method. This acute value (EC 50 = 164) is lower than any cited in EPA’s Revie w. The EU Report also cites a valid Daphnia magna chronic data (21d) = 175 mg/L (EC 20 , an endpoint typically used by EPA in their water quality criteria development). This is nearly 3 times EPA’s predicted value of 52 mg/L (p. 16). I would also note tha t a 16d EC 50 is not considered an acceptable chronic endpoint for Daphnia by either EPA OPPT or EPA OW. ( peer reviewer 1 )

EPA Response: The rainbow trout and fathead minnow acute data, as well as the chronic daphnid EC value, are from unpublished indust ry reports (e.g., “INERIS, 1999” or “Dow Chemical Company, 1979”).Page 8 of 17

Because they are unpublished, EPA was unable to obtain th e reports. T he data are now referenced as “as cited in the EU Risk Assessment Report on EGBE.”

T he source of the Brachionus calyc iflorus data (Devillers et al., 2002) was retrieved, evaluated and
included in the assessment. In addition DeVillers et al. (2003) and Dill & Millazzo (1988), both cited in the EU Report , were also retrieved, evaluated, and included in the assessment

.

T he predicted 16

- day EC 50 value was replaced with chronic predicted values that are available from the latest version of ECOSAR (released in 2008).

Comment 2

- 4: For chemicals like EGBE that have few valid data, EPA should consider using EPA’s Interspecie s Correlation Estimation (ICE procedure) http://www.epa.gov/ceampubl/fchain/webice . This procedure might be informative in this case because valid data are available for several commonly tested

spe cies (e.g., Daphnia , fathead minnow, trout, bluegill, silverside). ( peer reviewer 1 )

EPA Response: T he available experimental toxicity data (as well as predicted values) are sufficient for the purposes of this assessment.

Comment 2

- 5: The literature search appears to be thorough and the conclusion that EGBE is not expected to present a significant concern for adverse effects is sound. All of the aquatic toxicology data were for acute bioassays. The lack of chronic data resulted in the use of quantit iative structure activity relationships (QSARs) and EPA’s Ecological Structure Activity Relationship Program (ECOSAR) to supplement existing data and predict chronic effects. While this appears adequate, the extrapolation of individual effects to populati on level effects should be explored. Can the Daphnia magna data in Table 2.2 be extrapolated to population level effects? What is the implied endpoint in the chronic effects prediction for D. magna? If it is reproduction then population level effects co uld be inferred. ( peer reviewer 2 )

EPA Response: The extrapolation to population effects is beyond the scope of this assessment. The focus of these types of assessements is to present acute and chronic toxicity data for individual effects.

Comment 2

- 6: The summary statement is focused heavily on chemical properties, production and usage of EGBE rather than environmental fate. Some of the important information regarding toxic products formed in the atmosphere, and potential health effects from exposure to such toxic products are notPage 9 of 17

mentioned in the summary. I would suggest that a paragraph on different atmospheric transformation products of EGBE and the formation of peroxyacyl nitrates (PANs) should be given in the summary. I
would also add a statemen t to note that PANs are components of photochemical smog. Mutagenic property of PAN (P9, line 10), formation ozone and its effect on human health are not mentioned in the

summary. ( peer reviewer 3 )

EPA Response: The following has been added to the summ ary section of the report to provide the reader additional information on the toxic transformation product of EGBE in the atmosphere and the associated
adverse effects

.



### “ EGBE may contribute to the formation of tropospheric ozone (Derwent et al., 1996; U.S. EPA, 1996). Degradation products can result in the formation 2

- butoxyacetic acid (BAA) (see section 1.6.5) as well as peroxyacyl nitrates, (Atkinson, 2000; LOOP, 2003). In mammals 2

- butoxyacetic acid is thought to be responsible for EGBE’s toxic hem atolog ical effects (U.S. EPA, 1999)

. Peroxyacyl nitrates (PAN) have been reported to be eye irritants, mutagenic, phytotoxic, and possible agents of skin cancer (Singh and Salas, 1989; Williams et al. 1993). PAN has been shown to be mutagenic in Salmonell a and in the lungs of mice exposed nose

- only to PAN generated from non

- mutagenic precursors (DeMarini et al., 2000). ”

Comment 2

- 7: Information on the high water solubility and potential for groundwater contamination by
EGBE is not mentioned in the summar y. ( peer reviewer 3 )

EPA Response: The following has been added to the report summary:



### “EGBE released to soils and sediments is not expected to strongly absorb and has the potential to migrate into underlying groundwater systems (Hansch et al., 1995; HSDB, 2007; Staples et al., 1998 ; U.S.EPA, 2008 ). ”

Comment 2

- 8: I would also add statement regarding soil and biological degradation products. If there is no information regarding soil degradation products, that should be mentioned. For biota, there a re studies that show that EGBE degrades to produce butoxy acetic acid which can cause hemolysis and this should be mentioned in the summary. ( peer reviewer 3 )

EPA Response: There is no reliable information regarding soil degradation products for EGBE in the environment. This statement can be added to the summary. The degradation of EGBE to butoxyacetic acid (a biomarker of EGBE exposure) is a mammalian toxicology issue, and thus was not addressed in the ecological hazard assessment.Page 10 of 17

Comment 2

- 9: Th e summary statement appears to be biased, overall, as information regarding toxic effects or ecological hazards are not mentioned. Very few studies have reported aquatic toxicity of EGBE. The available aquatic toxicological data are not from systematic s tudies with standard protocols. The data are inadequate to draw conclusion on ecological hazard. This needs to be mentioned in the

summary. ( peer reviewer 3 )

EPA Response: The summary statement for Chapter Two does in fact mention ecological toxicity

– and
cites Table 2

- 2 for the summary of values. The summary further states that toxicity is not high

– “... indicating low to moderate aquatic toxicity (Table 2

- 2).”

Comment 2

- 10 : Some of the literature selected for this review is not up to date and so me are biased. A cursory look at literature of EGBE has shown several new literature including toxic effects. For example, there is a review on ecotoxicity of EGBE. See TOXICOLOGY MECHANISMS AND METHODS
Volume : 12 Pages: 255

- 263 (2002). Also see, ENVIR ONMENTAL TOXICOLOGY Volume: 14 Issue:
5 Pages: 481

- 522 (1999). ( peer reviewer 3 )

EPA Response: Devillers et al. (2002) was retrieved, evaluated and included in the assessment.

T he second reference the peer

- reviewer mentions (Kent et al., 1999) was ev aluated and it was determined not appropriate for inclusio n in the assessment because it ’s a review that only covers ethylene glycol, propylene glycol, and diethylene glycol

– not EGBE.

As for other new literature that may exist on the ecological toxic ity of EGBE, another ECOTOX search
was conducted and the search resulted in one new “hit.” The ECOTOX search conducted in preparation for the original assessment on October 25 2007 resulted in 35 hits; the subsequent ECOTOX search conducted in April 2009 had 71 hits, and the additional 36 hits are all from one additional reference

-- Adema, D.M.M. 1985 . Aquatic Toxicity of Compounds that may be Carried by Ships (Marpol 19733 Annex II). A Progress Report for 1985. Source: Tech.Rep.No.R85/217, TNO, The Hag ue, Netherlands :40 p. Thus there is not much additional ecological toxicity data available.

Comment 2

- 11 : The summary is excellent, but I would replace “infinitely soluble” with “completely miscible” on p1 line 12. Overall it is well done and with the se minor changes should be acceptable. ( peer reviewer 4 )Page 11 of 17

EPA Response: The phrase “infinitely soluble ” will be replaced with “miscible”.

3. ADDITIONAL COMMENTS

Comment 3

- 1: The information presented in the Review of EGBE is accurate and interpretatio ns are generally accurate as well. EPA should consider including the European Union’s (EU) recent draft Risk Assessment of EGBE (2005): http://ecb.jrc.it/documents/Existing

- Chemicals/ RISK_ASSESSMENT/DRAFT/R408_0712_env_hh.pdf.
This risk assessment includ es more recent environmental effects data as well as possible updates to certain properties such as Henry’s Law Constant. ( peer reviewer 1 )

EPA Response: Data reported in the EU Risk Assessment have been reviewed and included in the
Technical Review whe re appropriate

.

Comment 3

- 2: p. 2, lines 5

- 6: Releases to water are reported to be 128,000 lbs but 5,061,000 lbs were transferred to POTWs. Not clear how you can have 5 million lbs to POTWs (i.e., water) and only have 128,000 lbs released to water. ( p eer reviewer 1 )

EPA Response : Data reported to TRI as transferred to a POTW is not counted as released directly to water since no data on the treatment efficiency of the POTW is reported to the TRI. TRI d ata users can assume no treatment or some percent age treatment depending on what happens to the chemical at the POTW and then include those quantities as released to water from the POTW.

Comment 3

- 3 : p. 6, line 1: The model lake is only 3m deep? I would call that a pond at best. What is
the volatil ization half

- life for a lake 10

- 20m deep (i.e., more representative lake in North America)? ( peer reviewer 1 )

EPA Response: The model defaults for a “model lake” were used for this calculation. The purpose of this calculation is to provide a general co mparison between a flowing body of water (model river) and a relatively stagnant body of water (model lake). This model was not designed for the increased complexities involved with chemical volatilization from deeper lake systems.

Comment 3

- 4 : p. 8, l ine 3: Lack of anaerobic biodegradation information should be acknowledged as a critical data gap because EGBE has a propensity to move to groundwater where volatilization isPage 12 of 17

negligible. Spills of EGBE to groundwater could pose a health risk to drinking water supplies perhaps. ( peer reviewer 1 )

EPA Response: Data gap statements will be limited to a brief indication that the information was not
located. Th e statement on p. 8, line 3 has been modified to indicate that anaerobic conditions include ground water.

Comment 3

- 5: p. 13, line 7: ...effects occur at relatively high concentrations that are never observed under normal circumstances (i.e., EGBE degrades rapidly)

. ( peer reviewer 1 )

EPA Response: Italicized text added to the Chapter Two Summary to reflect the reviewer comment as

“ Such high concentrations are not expected to be observed under typical environmental conditions. ” The parenthetical comment was not added because it is not clear that rapid degradation is the sole cause of the
observed environmental concentrations.

Comment 3

- 6 : This review appears to be pretty thorough and should provide information (with the caveats discussed below) required for section 313 of the Emergency Planning and Community Right

- To

Know Act. However, the review appears to be a quick compilation of fragm ents from manuscripts and documents without attention to a methodical discussion of the salient information. For example, the summary is a series of sentences largely taken from the different section and gives the reader the impression that little effort was spent in editing this document and making it more readable. Having said that, it may be that the readability of this document may not be important. If so, disregard the above
remarks. ( peer reviewer 2 )

EPA Response: General edits were made to the document to improve the readability from one
discussion to the next.

Comment 3

- 7 : Page 4, Column 1 of Table 1

- 1: “Molecular Formula” should be “Molecular f ormula” and “Molecular Weight” should be “Molecular w eight”. ( peer reviewer 3 )

EPA Response: Th ese c hange s have been made as suggested.

Comment 3

- 8 : P6, lines 9

- 10: It has been stated that EGBE has a potential to move from soil to groundwater. However, further details regarding groundwater pollution or distribution of this compoundPage 13 of 17

in groundwate r is lacking. This should be highlighted in the summary and should be stated as an area for future investigation. ( peer reviewer 3 )

EPA Response: The f

ollowing sentence was added to the text of this section: “Additional information regarding the trans port of EGBE through soil, sur face water, and groundwater has not been located in the available literature.” As mentioned above, data gap statement is limited to a brief indication that the
information was not located.

Comment 3

- 9: P8, line 17

- P9, li ne 11: Atmospheric transformation of EGBE has been discussed. While it is stated that EGBE photooxidizes to produce several air pollutants including peroxyacyl nitrates (PANs). The PANs are important constituents of Photochemical smog. This is not ment ioned either in summary or in the environmental fate section. If direct release of EGBE into air was higher than that in soil or water, then discussion on photochemical smog is important. ( peer reviewer 3 )

EPA Response: Information on the formation of the EGBE degradation products resulting in the production of PAN and BAA has been placed in both the summary and the Toxic Transformation Products sections of the report

Comment 3

- 10 : P7, line 9: ‘Topospheric’ should be “T r opospheric” . ( peer reviewer 3 )

EPA Response: This c hange has been made as suggested.

Comment 3

- 11 : P5, line 21 and P6, line 2: “slowly” is a subjective term. How slowly? I would avoid such subjective terms. A similar problem on P7, line 15: “rapidly” How rapidly?? Such subje ctive terms introduce bias to this report. ( peer reviewer 3 )

EPA Response: The volatilization classification scheme in Lyman (1990) is now cited to provide further support for the statement regarding slow volatilization; estimated volatilization half

- li ves are also provided in the next sentence. The phrase “biodegrades rapidly” has been changed to “is readily biodegradable” with references added to support this classification.

Comment 3

- 12: P13: Line 6

- 7: This statement reads biased. There is no st rong evidence to support this statement. First we do not have systematic studies with standard protocols to measure aquatic toxicity. Second, no chronic, long term exposure end points have been measured. The reported values are allPage 14 of 17

LC50 or LOEC; no NOEC is reported. Given these problems, the statement on P13, line 6

- 7 is not right. ( peer reviewer 3 )

EPA Response: The sentence was modified to read “ Based upon available acute toxicity data, EGBE does not appear to present a significant concern for adv erse effects on the aquatic environment since effects occur at relatively high concentrations that are have not been observed under normal
circumstances. ” EPA believes that the available toxicity data and estimated toxicity values are sufficient
to conclu de that EGBE has low to moderately low ecological toxicity.

Comment 3

- 13 : P15, Table 2

- 1: Column 1, “Henry’s law constant” c heck the spelling. ( peer reviewer 3 )

EPA Response: The spelling has been changed to “Henry’s law constant”

.

Comment 3

- 14 : P 2, line 20: “rapid” How rapid? It is a subjective term. I would avoid or be specific. ( peer reviewer 3 )

EPA Response: The phrase “expected to undergo rapid biodegradation” has been changed to “considered to be readily biodegradable” with references a dded to support this classification.

Comment 3

- 15 : This review appears biased and incomplete. More information is available in the literature on the fate and toxicity of EGBE. An unbiased review of the available information is needed. EGBE is a very h igh production volume chemical and is used in large quantities in several products that we come in contact in our daily lives. There is a great potential for human and environmental exposures. ( peer reviewer 3 )

EPA Response: A search of the available literature was performed for EGBE. The relevant information has been summarized and presented in a factual manner in this review. No further changes will be made.

Comment 3

- 16 : The report is well written and appears to be up to date. The interpretat ions are consistent with the reported data although at times they are a little loose and sweeping, e.g. EGBE does

not bioaccumulate. (A BCF of 3 represents small or slight but not zero bioaccumulation) There is some repetition, notably of Table 1.1 of che mical properties. ( peer reviewer 4 )Page 15 of 17

EPA Response: The phrase “not expected to bioaccumulate” has been changed to “not expected to bioaccumulate significantly”.

Comment 3

- 17 : In other reports the EPIWIN output has been supplied with the report on the C D. This was not the case with EGBE. I suggest that in view of the heavy reliance on that software the actual output be appended to the report. ( peer reviewer 4 )

EPA Response: A pdf file was generated from the EPI Suite output for reference.

Comment 3

- 18 : Correlations between K OW and K OC and BCF are used but it should be noted that these correlations are largely based on substances with log K OW ranging from 2 to 6. Since log K OW of EGBE is 0.83 there is a real possibility of poor correlation. This i s apparent in the K OC estimated. A cautionary
note should be included to this effect. ( peer reviewer 4 )

EPA Response: A calculated value of 7.6 from the new EPI Suite software (version 4.00 ) is now used
instead of the value of 67 currently in the Techn ical R eview. The new Koc model can perform a calculation based on the measured log Kow which was not possible with the previous versions of EPI
Suite where a separate calculation was required. In addition, t he new model contains a larger training set
and improved equations compared to the older method

.

Comment 3

- 19 : P1 line 9 I believe the correct name is n

- butyl not N butyl. N implies nitrogen. (see p3 line 29). ( peer reviewer 4 )

EPA Response: This change has been made as suggested.

Comment 3

- 20 : P1 line 12 I prefer “completely miscible” to “infinitely soluble”. ( peer reviewer 4 )

EPA Response: The phrase “infinitely soluble” has been replaced with “miscible”.

Comment 3

- 21 : P1 line 26 delete “greater than”? ( peer reviewer 4 )

EPA Response: Th is change has been made as suggested.Page 16 of 17

Comment 3

- 22 : P4 Table 1.1 Can I suggest that the SI units be given as well for each property including vapor pressure, solubility and HLC? ( peer reviewer 4 )

EPA Response: For the sake of clarity, SI units will no t be added to the table.

Comment 3

- 23 : P5 line 21 I suggest that the air

- water partition coefficient K AW be given as well. This is
H/RT with R in units of atm.m 3 /mol.K. R is 8.314 Pam 3 /mol K or 82 x 10

- 6 atm m 3 /mol K K AW is then
65.5 x 10

- 6

. ( peer rev iewer 4 )

EPA Response: The nature of EGBE volatilization has been captured through the use of the Henry’s law
constant value. There is no need to include the air

- water partition coefficient (K AW ).

Comment 3

- 24 : P6 log K OW is 0.83 so K OW is 6.76. A BC F of 3 is thus reasonable but the K OC of 67 seems very high. Usually K OC is about 35% of K OW . It would be more accurate to state that ‘EGBE is not expected to adsorb (or sorb) strongly to soils.... ( peer reviewer 4 )

EPA Response: The new K oc value of 7.6 will be used as discussed abov e. The language on p.6 has
been changed as requested.

Comment 3

- 25 : In the fugacity model was K OC input or K OW ? Most models assume K OC is approximately 0.4 K OW . It may be that the model uses a different K OC from that suggested in the report,
i.e. one calculated from K OW . ( peer reviewer 4 )

EPA Response: The fugacity calculation has been performed again. The new Koc value of 7.6
mentioned above was used for this calculation.

Comment 3

- 26 : Line 3 It would be clearer to state that Bidleman suggests that only x% of EGBE will be associated with aerosols. It would help to calculate K OA as K OW /K AW . It is about 10 5 so sorption to
aerosols at normal aerosol concentrations of 10

- 11 volume fraction is minimal, i.e. about 10

- 6 . The
conclusion is correct. ( peer reviewer 4 )

EPA Response: This sentence was replaced with the following: “Using this vapor pressure value, a calculated particle/gas partition coefficient of 2.05×10

- 6 indicates that any EGBE that is released into the air will exist primarily as a vapor (Biddleman, 1988; U.S. EPA, 2008)

. ”Page 17 of 17

Comment 3

- 27 : p13 the concern for adverse effects in aquatic systems depends on the prevailing EGBE concentration as well as toxicity. It does seem unlikely that environmental c oncentrations will reach about 1000 mg/L (which is 0.1%) except near spills or leakages. The sentence in line 6 is perhaps a bit broad and sweeping. Toxicity could occur under extreme conditions. ( peer reviewer 4 )

EPA Response: See response to comment 3

- 12 above.

Comment 3

- 28 : P15 Table 2.1 is essentially Table 1.1. Why repeat it? ( peer reviewer 4 )

EPA Response: Table 2.1 has been removed from the document.