2 

### Comments Related to the Environmental Fate Data Requirement s

AMVAC Comment : Dissociation Constants in Water (OCSPP 830.7370), for all of NAA compounds except naphthalene acetic acid: AMVAC indicated that the dissociation of NAA and its different salts will be dete rmined by the proton affinity of the carboxylic acid substituent and the pH of the surrounding aqueous solution. In the environment, the pH will be determined predominantly by the ions and their complexes in the water and equilibria with the surrounding

s oil, rather than by the much lower concentration counter ions (sodium, potassium, or ammonium) associated with the initial NAA salt.

The pKa of the sodium salt was determined to be 4.1 (Greenwood

, 2005) 1 . In the literature, the pKa for NAA is reported at the comparable value of 4.2 (TOXNET). These values demonstrate that NAA and its associated salts will be more than 99% dissociated in ponds, lakes, and rivers, which typically have pHs in the range of 6.5

‐ 8.5. The molecular species of NAA and all of its associated salts in the environment will be the same dissociated organic anion. T he environmental fate of NAA and its salts relate to that of the dissociated anionic species. On this basis, AMVAC find s it appropriate to apply the dissociation constant d etermined for the NAA sodium sa lt to NAA and its other salts.

Concerning the ethyl ester and acetamide of NAA, they are distinct chemical entities but, due to structural considerations, do not participate in acid/base equilibrium. Therefore, these two NAA based compounds do not have a meaningful dissociation constant and are fully associated under environmental conditions.

AMVAC requested a waiver for any new studies to measure dissociation constant.


### EFED Response : The purpose of the requests for physicochemical data for NAA related compounds is to confirm certain values derived from modeling ( e.g. , EPISUITE) and/or available from external sources . The Division has a study that indicated that the pKa of NAA acid is 3.5 (MRID 40522903). This value also indicates a high tendency for the acid to be dissociated under typical environmental conditions. Based on this pKa, i t appears that the salts will also be typically dissociated in the environment, and this is also supported by the study cited by AMV A C for the sodium salt, for which the pKa was 4.1 ( Greenwood

, 2005). However, t he Division inspected the cited study (cited in the comments under MRID 40523003) and found that the pKa in this citation was for the NAA (acid) instead of the sodium salt, whi ch is 3.5

. F urther , the study was performed by a different author and year ( Feiler , 1987). EFED would like to confirm the pKa of 4.1 for the sodium salt cited above, and requests the registrant to submit the study or provide the correct MRID citation. B ased on the data to be provided by the registrant, EFED may assume that the acid form of NAA and its salts are fully dissociated in the environment and that the results of studies conducted on the acid and the sodium salt are representative of other salts

. Regarding the ethyl ester and acetamide of NAA, the registrant indicated that these species do not

1 Greenwood, J.; Liney, P. (2005) 1

‐ Naphthaleneacetic acid sodium salt (purified): physicochemical properties, Covance Laboratories, Ltd., Study Report 1708/040

‐ D2149, AMVAC Report 400

‐ PCH

‐ 037 ( cited under MRID 40522903)

.3 have structural moieties participating in acid/base equilibrium and do not have a mea ningful dissociation constant.

EFED requests the registrant to submit the study for the sodium salt or provide the correct MRID citation for Greenwood and Liney ( 2005 )

. O nce the study is submitted , EFED will consider using the pKa for the sodium salt in place of the potassium and ammonium salts.

Additionally, EFED recommends to remove the Dissociation Constant data requirement f or the ethyl ester and acetamide forms of NAA.



### AMVAC Comment : Water Solubility (OCSPP 830.7840/ 830.7860) for naphthalene acetamide and naphthalene acetic acid, potassium and ammonium salts : AMVAC said it will provid e EPA with an existing water solubility study for the NAA acetamide (Jentoft 1996, AMVAC Report 400

‐ PCH

‐ 049 ).

For NAA, the solubility of this carboxylic acid is pH dependent. However, at environmental pHs ( i.e. , 6

‐ 8), the comp ound will be in its dissociated form and exist as a salt complex with the
counter

‐ cations that are available in solution. All of the salts of NAA are predicted to be highly water soluble. For example, EPA has a study on the sodium salt that determined a water solubility of 295.5 g/L at 20.1°C (Greenwood

, 2005). The potassium and ammonium salts are expected to have similar solubility and the concentration of these salts within their respective formulated aqueous products demonstrates this contention. K

‐ Sa lt Fruit Fix 800 (Registration No. 5481

‐ 413) is 24.2% potassium salt by weight and Fruit Fix Concentrate 800 (5481

‐ 130) is more than 22.8% by weight. These products contain no adjuvants and are prepared by simply combining either potassium hydroxide or am monia to NAA in water to make the respective salts.

Due to the high solubility associated with these products, it should be appropriate to simply list both the potassium and ammonium salts as having water solubility greater than 20% by weight ( i.e. , >200, 000 ppm). This value should also be applied to NAA in consideration of its solubility at an environmental pH. Further, NAA is not sold in its acid form as a product. On this basis, AMVAC is seeking waivers for water solubility studies for NAA, the potas sium salt, and the ammonium salt.


### EFED Response : The Division has a study conducted on the acid form of NAA that indicates that the solubility is 420 mg/kg at 26°C ( MRID 40522903 ). As indicated by the registrant, t he solubility of the acid is pH dependent ; however, the pH of the solution in the available study is not stated . The registrant

- cited study on the sodium salt (Greenwood 2005

, under MRID 40523003) was located by the reviewer, but it was found that it was conducted in a different year an d by a different author ( Feiler , 1987 ) than the MRID citation provided. According to the submitted study (MRID 40523003) , the solubility of the sodium salt of NAA is 3 40 g/100 g or 3, 4 0 0,000 mg/kg at 26°C. Finally, EFED has a study conducted with the eth yl ester of NAA that indicates that the s olubility is 105 mg/L at 25oC (MRID 47505905)

. EFED will consider using the very high solubility of the sodium salt in place of the ammonium and potassium salts of NAA

. Furthermore, EFED looks forward to the submi ssion of an existing solubility study for NAA acetamide.4 

### AMVAC Comment : N ‐O ctanol/Water Partition Coefficient (OCSPP 830.7550/830.7560/ 830.7570), for naphthalene acetic acid and naphthalene acetamide : AMVAC indicated it will provide a partitioning study for NAA acetamide. However, the testing of an organic acid such as NAA that would be highly dissociated in the environment should not be necessary as ionic species will exhibit minimal partitioning behavior in non

‐ polar solvents at environmental pHs. On this basis, AMVAC is seeking a waiver for conducting a partitioning study on NAA and only performing the partitioning study on the acetamide.


### EFED Response : On the basis of a pKa ranging from 3.5 for naphthalene acetic acid (MRID 40522903) to the sodium salt of 4.1 (Greenwood and Liney, 2005 , a study to be submitted or citation provided by the registrant), the acid and its salts should exist in the dissociated form as naphthalene acetate and its counter cation at environmentally relevant pHs (

~ 6

- 8). Ther efore, the Octanol/Water Partition Coefficient data requirement conducted on the acid is not required

. Furthermore, the Agency is looking forward for the study AMVAC committed to conduct on the acetamide.



### AMVAC Comment : Vapor Pressure (OCSPP 830.7950) f or all salts, ethyl ester, and amide : AMVAC said that organic salts have extremely low vapor pressures and measurements are typically obscured by low level impurities. Therefore, such measurements are not provided by chemical distributors on MSDSs for acet ate salts. For these salts, low level impurities, including acetic acid or ammonia are known to impair the extremely low measurements required for determining the vapor pressure of the pure salts. For this reason, AMVAC is seeking waivers for
vapor press ure testing of any of the NAA salts; but commits to conducting a study on the ethyl
ester. AMVAC has already performed a study on the acetamide (Lorence 1996, AMVAC Report 400

‐ PCH

‐ 054) , and will provide it to the Agency.


### EFED Response : The vapor pressure for the acid is 0.3 torr at 26°C ( MRID 40522903 ). EFED will use this data in place of the V apor P ressure data requirement f or the NAA sodium, potassium and ammonium salts , since salts are not expected to volatilize substantially . Further, EFED welcomes the submission of the already available study on the acetamide

, and a new study
t hat the registrant committed t o perform on the ethyl ester.



### AMVAC Comment : Aerobic Soil Metabolism (OCSPP 835.4100) for naphthalene acetic acid and naphthalene acetamide : AM VAC propose s to address the study requirements for both NAA and the acetamide by conducting the required studies for the acetamide and using those studies to determine the kinetics of both the acetamide and NAA. Because the first step in the degradation o f the acetamide is anticipated to be conversion to the acid, appropriate scheduling of sampling in the protocol will permit the determination of the formation and degradation constants of NAA.


### EFED Response : EFED believes that a study conducted on the ace tamide may provide suitable information about the degradation pattern of both the acetamide and the acid, as proposed5 by AMVAC, assuming that NAA acid is the primary degradate of the acetamide . The registrant is advised that all the transformation product s of both chemicals >10% AR must be identified and the patterns of formation and decline clearly established. The degradation pathways for NAA

ac etamide and for NAA acid should be provided. The study should be conducted in four soils

. N ote that previously the Preliminary P roblem F ormulation request ed two soils for the acid and two soils for the acetamide

.



### AMVAC Comment : A erobic A quatic M etabolism (OCSPP 835.4300) for naphthalene acetic acid and naphthalene acetamide: AMVAC believes that by expe rimentally determining the aerobic soil metabolism half

‐ life for NAA and NAA acetamide, a more definitive assessment of the potential for microbial degradation would be determined. EPA has traditionally applied a factor of 2X to the aerobic soil metabolis m half

‐ life in estimating chemical degradation kinetics in a water phase associated with the sediment.

AMVAC contracted Stone Environmental for conducting a sensitivity analysis for the aerobic aquatic metabolism parameter on surface water exposure. This assessment utilized the QSAR modeled K OC and aerobic soil metabolism half

‐ life value previously determined by EPA and reported in the recent Problem Formulation. The sensitivity analysis assessed the extent to which surface water concentrations would cha nge by modifying the aerobic aquatic metabolism half

‐ life. The half

‐ life was modified over a range of values that included the likely aerobic soil metabolism half

‐ life of 10 days as calculated by EPA using EPISUITE and a half

‐ life as long as 164 days. The assessment was conducted on the product use pattern for the FL citrus scenario.

According to AMVAC, t he sensitivity analysis demonstrates that by conducting an aerobic aquatic metabolism study and refining EPA’s default 2X the aerobic soil metabolism hal f

‐ life approach, there would be no significant change in the modeled calculation of surface water concentrations. In the determination of the acute surface water concentration, refining the aerobic aquatic metabolism half

‐ life would yield a negligible cha nge on the peak surface water concentration over a wide range of aerobic aquatic half

‐ lives. Also, this refinement would only yield a minor change in the average surface water concentration of 1.5X.

Further, AMVAC said that there is information within the literature indicating that the metabolism of NAA in aquatic systems would likely be comparable to that associated with terrestrial environments. Information concerning the degradation of certain surrogate compounds provides insight into this issue. As N AA is a polycyclic aromatic compound, one would expect microorganisms capable of degrading these commonly occurring chemicals to be abundant in both terrestrial and aquatic environments. Previous studies have demonstrated that naphthalene is efficiently m ineralized in diverse aquatic environments (Heitkamp 1987) 2 . Such metabolism entails initial oxidation of the aromatic ring system through the formation of cis

‐ 1,2

‐ dihydroxy

‐

2 Heitkamp, M. A.; Freeman, J. P.; Cerniglia, C. E. (1987) Naphthalene biodegradation in environmental microcosms: estimates of degradation rates and characterization of metabolites, Appl. Environ. Microbiol. 53 (1), 129

‐ 136.6 1,2

‐ dihydronaphthalene by bacteria (Heitkamp 1987, Alquati 2005, Madhumita 2012) 3 and of the
trans

- isomer by fungi (Cerniglia 1978) 4 . NAA, which contains the naphthalene structure within its core would be predicted to serve as a reasonably good substrate to these same organisms, especially given the fact that current data suggests tha t NAA itself would not likely display any significant toxicity to microorganisms [no source or evidence for this statement provided] . NAA would also be predicted to degrade through formation and degradation of CoA

‐ thioesters catalyzed by ubiquitous phenyl acetyl

‐ CoA ligases found in the environment (Magdy 2000, Navarro

‐ Llorens 2005, Shrivastava 2011) 5

.

On the basis of th e above information, AMVAC is seeking a waiver from conducting aerobic aquatic metabolism studies for both NAA and NAA acetamide. AMVAC p ropose s that the 2X factor be applied to the aerobic soil metabolism half

- life value that will be determined by AMVAC in an upcoming study.


### EFED Response : At this time, the registrant has not submitted for review any information about the aerobic soil or aerobic aquatic metabolism of NAA acid or the acetamide , or their degradation pathways. An European Union study yielded DT 50 ’s for the total system in two sediments are 6.2 and 9.5 days, suggesting that NAA acid degrades faster than previously assumed in modeling . No degradates were identified ( source: public Draft Assessment Report, or DAR, Volume 3, Annex B, part 5, B.8, pp. 576

- 582, dated August 2008) . EFED believes that an aerobic aquatic metabolism study is highly desirable for NAA (acid) and the ac etamide , especially in the absence of any other degradation information about these chemicals to date. Nonetheless, in the absence of an aerobic aquatic metabolism study, EFED will use a 2X factor ( i.e.
, twice the aerobic soil metabolism input value), per the current Input Parameter Guidance , v.2.1 6

.



### AMVAC Comment : Adsorption/Desorption (Batch Equilibrium) (OCSPP 835.1230), for naphthalene acetic acid and naphthalene acetamide : AMVAC reviewed EPA’s information concerning the calculation of a K OC value using EPISUITE v.4.1 and believes that the determined value is appropriate for use in groundwater and surface water modeling assessments. Th e review by Wang ( 2015) 7 provides data demonstrating that quantitative structure

‐ activity relationship

3 Alquati, C.; Papachini, M.; Riccardi, C., Spicaglia, S., Bestet ti, G. (2005) Diversity of naphthalene

‐ degrading bacteria from a petroleum contaminated soil. Ann. Microbiol. 55 (4), 237

‐ 242. Madhumita, R.; Khara, P.; Dutta, T. K. (2012) meta

‐ Cleavage of hydroxynaphthoic acids in the degradation of phenathrene by Sphing obium sp. Strain PNB. Microbiol. 158, 685

‐ 695.

4 Cerniglia, C. E.; Gibson, D. T. (1978) Metabolism of naphthalene by cell extracts of Cunninghamella elegans

. Arch. Biochem. Biophys. 186, 121

‐ 127.

5 Magdy, E

‐ S. M. (2000) Biochemical and molecular characterization of Phenylacetate

‐ Coenzyme A Ligase , an enzyme catalyzing the first step in aerobic metabolism of phenylacetic acid in Azoarcus evansii . J. Bacteriol. 182 (2), 286

‐ 294. Navarro

‐ Llorens, J. M.; Patrauch an, M. A.; Stewart, G. R.; Davies, J. E.; Eltis, L. D.; Mohn, W. W. (2005) Phenylacetate catabolism in Rhodococcus sp. Strain RHA1: a central pathway for degradation of aromatic compounds. J. Bacteriol. 187 (13) 4497

‐ 4504. Shrivastava R.; Purohit H.; Phale P. S. (2011) Metabolism and preferential utilization of phenylacetic acid and 4

‐ hydroxyphenylacetic Acid in Pseudomonas putida CSV86. J Bioremed Biodegrad 2, 120

‐ 130.

6 Available at http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm (accessed 03/27/2015).

7 Wang, Y.; Chen, J.; Yang, X.: Lyakurwa, F.; Li, X.; Qiao, X. (2015) In silico model for predicting soil organic carbon normalized (K OC ) of organic c hemicals, Chemosphere 119, 438

‐ 444.7 ( QSAR ) assessments [ including EPA’ s PCKOCWIN (MCI) and PCKOCWIN (L og K OW ) ] are accurate predictors of K OC for carboxylic acid compounds such as NAA. Only in one case ( i.e.
, endothal) was the predicted K OC value not accurately determined. In this case, the act ual value was higher; thus the modeling exaggerated the leaching potential for this compound. [EFED note: When K OC is higher, the leaching potential is smaller, not higher.]

The K OC value determined for NAA by EPA using EPISUITE v. 4.1 is 24.82 mL/g OC , w hich appears to be reflective of the low soil binding potential of an ionized species. AMVAC believes that this value is sufficiently conservative for the EPA to continue to rely on this value in its modeling assessment of environmental concentrations in water.

AMVAC w orked with Stone Environmental who performed a sensitivity analysis on the K OC of NAA. AMVAC ’s comments provide results of acute and chronic estimated drinking water concentrations (EDWCs), for groundwater and surface water that were used f or assessing the sensitivity of the K OC parameter on predicted concentrations in water. The K OC evaluation was conducted for the FL citrus scenario. A 2X increase in the modeled QSAR K OC value is the maximum increase expected for a highly water soluble c ompound that would be ionized in the environment. Because the aerobic soil metabolism half

‐ life has not yet been firmly established, several different aerobic soil metabolism half

‐ lives ranging from 10

– 132 days were explored in the sensitivity assessmen t.

For surface water , sensitivity analysis demonstrates that the change in acute NAA concentration associated with a 2X increase in the K OC would yield a concentration reduction of 1.0

– 1.1X. This change would also yield a reduction in the chronic (avera ge) surface water concentration of 1.1X. These reductions are clearly insignificant. The sensitivity analysis determined that the change in peak NAA groundwater concentration associated with a 2X increase in the QSAR K OC would yield only a 1.3

– 3X reduc tion. This K OC change would also yield a reduction in the post

‐ breakthrough average groundwater concentration of 1.2

– 2.6X. These reductions are relatively insignificant compared with reductions associated with changes for other environmental parameters. For example, a change in the aerobic soil half

‐ life from 10 to 30 days would yield a reduction of 4.9X for the peak ground water concentration and of 6.2X for the post breakthrough average concentration, assuming the QSAR K OC of 24.82 mL/g OC

.

As the EPA has stated in its recent Problem Formulation assessment that, “ I n the absence of data, conservative assumptions will be made for NAA and its derivative compounds”, AMVAC believe s that utilization of the current K OC values provides a sufficient and satisfa ctory means for conservatively assessing groundwater and surface water concentrations associated with product use. Further, as NAA is applied at a higher concentration than NAA acetamide and is more mobile, it represents a worse case assessment for the ch emical group. Due to the lack of sensitivity of this parameter on predicting groundwater and surface water concentrations, the QSAR K OC value determined for NAA would provide a sufficient and satisfactory means for conservatively assessing groundwater and surface water concentrations associated with product

use.

On this basis, AMVAC is seeking a waiver from conducting adsorption/desorption studies for both NAA and the acetamide and is propos ing to use the QSAR model

‐ based K OC value determined by the Agenc y for all NAA based assessments.8 

### EFED Response : It was noted that the sensitivity analysis did not explore the possibility that the K OC would be lower than predicted by EPISUITE . Chemicals with lower K OC s may contaminate surface waters mostly dissolved i n runoff waters, in events occurring shortly after application or groundwater by leaching , depending on their persistence . However, it is noted that the European Union study shows K OC values ranging from 68.5

– 138 cm 3 /g OC and the K FOC were 43.5

– 88.5 cm 3 /g OC ( with 1/n range of 0.815

– 0.866) , for three soils tested . These values compare favorably with EPISUITE v. 4.1 result of 24.82 mL/g OC for NAA acid ( source: public Draft Assessment Report, or DAR, Volume 3, Annex B, part 5, B.8, pp. 556

- 559, dated Au gust 2008)

. If the registrant submits the EU study, and it is found to be acceptable or supplemental, the Agency may rely on th at study in conducting the drinking water exposure and ecological risk
assessments

. Note that the study cited in the DAR is for NAA, while there are no studies submitted on the acetamide. Therefore, a study on NAA acetamide is also required.



### AMVAC Comment : Environmental Chemistry Method/Independent Laboratory Validation (ECM/ILV

, OCS PP 850.6100), for naphthalene acetic acid and naphthalene acetamide: AMVAC said that it intends to conduct this study in accordance with EPA’s requirement.


### EFED Response : The Division is looking forward to the submission of the above mentioned ECM/ILV re ports.



### Comments Related to the E cological Effects Data Requirement s

AMVAC Comment : 850.1010. Acute toxicity to freshwater invertebrates TGAI, naphthalene acetamide 850.1035. Acute toxicity to estuarine / marine invertebrate (mysid) TGAI, naphthalene acetamide 850.1075 Acute toxicity to estuarine / marine fish TGAI, naphthalene acetamid e 850.1300 Chronic Toxicity to Freshwater Invertebrates TGAI, naphthalene acetamide

AMVAC indicated that i f the freshwater fish chronic study (850.1400) on NAA ace tamide were to demonstrate toxicity that would yield a risk at an unacceptable level of concern, it would conduct these studies. On this basis, AMVAC proposes that th ese studies be listed as reserved until the results of the pending chronic fish study are reviewed.


### EFED Response : EFED noted in its Problem Formulation document that no aquatic animal toxicity data exists for the amide form of NAA, but that QSAR estimates of toxicity suggest that it may be of similar chronic toxicity as the ester form with respect to fish. Due to unc ertainty associated with QSAR estimates of toxicity for pesticides, EFED does not rely on QSAR estimates as the basis of its ecological risk assessments. However, EFED noted that in the absence of data, EFED would rely on measured toxicity data for simila rly structured compounds with the same mode of action ( e.g., Quinclorac and Quinmerac ) , however, these ecological toxicity data gaps would remain. EFED notes that submission of a c hronic early life stage fish
test for NAA acetamide would be useful in its future ecological risk assessment, but that given the high degree of variability in sensitivity between fish and invertebrate taxa, a single study for fish9 would not fulfill data gaps for invertebrate taxa. EFED would encourage the registrant to consider conducting a chronic toxicity test with Daphnia magn a, since this would help to resolve uncertainties regarding the sensitivity of aquatic invertebrates to NAA acetamide. Once a Data Call

- In is issued for these data, E FED will respond in detail to th e re gistrant’s proposal when submitted as a formal waiver request for 850.1010, 850.1035, and 850.1300

.



### AMVAC Comment : AMVAC has already provided an acute 48

‐ hour study for NAA on Daphnia magna (MRID 00082526) that EPA has determined to be acceptable. EPA concluded in their Problem Formulation assessment that the 48

‐ h EC50 of 180 mg/L is indicative of a chemical that is practically non

‐ toxic. This is because the EC50 is orders of magnitude higher than the predicted environmental concentrations (PECs) of NAA in groundwater and surface water. It is highly unlikely that EC50 for the acetamide would be significantly different as EPA’s QSAR 48

‐ h EC50 initial estimate for NAA of 540 mg/L was not significantly different from the measured value of 180 mg/L. EPA then applied a correction factor to the QSAR 48

‐ h EC50 for the NAA acetamide and determined a 48

‐ h EC50 of 147 mg/L, which is quite comparable to the NAA toxicity value. Even if the estimate for NAA acetamide was somewhat in error, it is highly unlikely to res ult in any level of concern for the chronic risk to this species.

However, AMVAC recognizes that there is no aquatic animal data at the moment for NAA acetamide; thus we propose conducting a chronic toxicity study on freshwater fish, which has been deter mined to be the most sensitive aquatic animal species to NAA and also according to EPA’s QSAR assessment. Assuming that this study were to yield an EC50 value that approximates the QSAR value of 0.15 mg/L, this value would be more than an order of magnitud e greater than the average surface water PEC and approximately an order of magnitude greater than the maximum surface water PEC. This would be clear evidence that the acute and chronic risk for fish and other aquatic animal species would not be of concern.


### EFED Response : See EFED’s previous response to the first comment above.



### AMVAC Comment : 850.2300 Avian Reproduction TGAI, naphthalene acetamide

. AMVAC’s intention is to bridge to similar mode of action studies and will contact the appropriate data submitters.


### EFED Response : At this time there is no chronic avian data available for any of the NAA related active ingredients. As indicated in its Problem Formulation document, in absence of data, E FED will evaluate the structural similarity of any propo sed chemicals for satisfaction of bridging to satisfy avian reproduction studies for NAA and related active ingredients. A MVAC has not indicated which chemicals will be proposed and whether data from these chemicals will be available for their use . EFED recommends a formal waiver request be submitted with a detailed rationale for bridging avian reproduction data for NAA and related active ingredients

,



### AMVAC Comment : 850.3020 Honey Bee Adult Acute Contact Toxicity TGAI, naphthalene acetic acid.10 AMVAC has a guideline contact study on honey bees made available by our business partner Agro

‐ Kanesho and we will provide this study to the EPA (Sidermann 2004) 8 . The study was conducted in accordance with OECD Guideline 214 and should address study needs as de fined by EPA Guideline 850.3020 per the Agency’s requirement as indicated in its Preliminary Work Plan. The completed study clearly demonstrates the safety of honey bees to contact exposure by NAA.


### EFED Response : EFED will make every effort to quickly rev iew the honeybee acute contact study mentioned above upon submission by the registrant. Until this study is submitted and reviewed, the data gap for the acute contact toxicity with the honey bee will remain.



### AMVAC Comment : OECD 213 Honey Bee Adult Acute oral Toxicity TGAI, naphthalene acetic acid.

AMVAC has a guideline oral study on honey bees made available by our business partner Agro

‐ Kanesho and we will provide this study to the EPA (Sidermann 2004) 9 . The study was conducted in accordance with OECD Guideline 213 and EPPO Guideline No. 170 per EPA’s requirement as indicated in its Preliminary Work Plan. The completed study clearly demonstrates the safety of honey bees to oral exposure by NAA.


### EFED Response : EFED will make every effort to quickly review the honeybee acute oral toxicity study mentioned above upon submission by the registrant. Until this study is submitted and reviewed, the data gap for the acute contact toxicity with the honey bee will remain.



### AM VAC Comment : Non

- Guideline Honey Bee 10 Day Adult Chronic Toxicity TGAI, naphthalene acetic acid.

AMVAC has a guideline contact study on a different species of larval insect, the Ladybird beetle, made available by our business partner Agro

‐ Kanesho and we will provide this study to the EPA (Tsukidate, 2004) 10 . The study evaluated dermal exposure to the post

‐ molting, 2nd instar larvae by dipping the larvae into a 400 mg ai/L solution and observing for 10 days in accordance with JMAFF Guideline for toxicity studies on natural enemy insects (2

‐ 8

‐ 3) in 13 Seisan 3986, “Of applying ‘annex guidelines for preparation of study results submitted when applying for registration of agricultural chemicals’”.

The study showed no mortality or abnormal behavior in the test organisms that c ompleted pupation within the 10

‐ day study window. Given the lack of an effect under these extreme dosing

8 Sidermann, A. B.; Porch, J. R.; Kruger, H. O. (2004) NAA

‐ NA: An acute contact toxicity study with the honey bee (OECD Guideline 850.3020), Unpublished study performed by Wildlife International LTD.

9 Sidermann, A. B.; Porch, J. R.; Kruger, H. O. (2004) NAA

‐ NA: An Acute Oral Toxicity Study with the Honey Bee (OECD Guideline 213 and 170), Unpublished study performed by Wildlife International LTD, Project Number 283

‐ 117, AMVAC Study No. 400

‐ NON

‐ 014.

10 Tsukidate, Y. (2004) A laboratory study to evaluate the toxicity of AKD

‐ 8147 technical against the ladybird beetle Coccinella septempunctata bruckii Mulsant, Unpublished study performed for Agro

‐ Kanesho Company, Ltd. By Eco

‐ Science Corporation, Project No. AMVAC Study No. 400

‐ EFF

‐ 009.11 conditions, it is reasonable to assume that there would also not be any effects of concern on honey bee larvae.

Also, the fact that the structural el ements of NAA are able to efficiently mimic the ubiquitous plant auxin 3

‐ indole acetic acid (3

‐ IAA) indicates that NAA would not be toxic to bees as 3

‐ IAA is ubiquitous to plants to which honey bees would be exposed. The important synergy between plants an d honey bees requires that 3

‐ IAA not be toxic to the adults or their larvae. Although 3

‐ IAA is primarily synthesized in the vascular tissue of the stem, protein regulation of 3

‐ IAA also

occurs within the pollen (Dal Bosco 2012) 11 ; thus insect and larval exp osure to this auxin is imminent. Due to the structural similarity of NAA to 3

‐ IAA, toxicity of NAA to honey bees at larval or adult stages would not be expected to be significantly different. In fact, the lack of toxicity of NAA and NAA acetamide to three different adult species of bees has recently been established for both NAA and NAA acetamide (Kim 2014) 12

. Further, given the longstanding use of NAA in the field, if there were problems related to hive performance, reports should have become evident. To our knowledge that is not the case. On the basis of this information, the available Ladybird beetle larval study should be sufficient to address the Agency’s concern regarding the potential toxicity of NAA to honey bee larvae and on that basis the substit ution of the Ladybird beetle study is proposed in lieu of the required honey bee larvae study.



### EFED Response : EFED will review the chronic exposure toxicity study with ladybird beetle mentioned above upon submission by the registrant. However, this non

- guideline test with a different non

- pollinator species of insect may not be adequate to satisfy the honeybee chronic toxicity data requirement as related to current OPP policy requirements for pollinator protection. EFED will also cons ider the arguments regarding similarity to 3

- indole acetic acid and it’s structural resemblance to NAA, however bridging another chemical’s toxicity information is not currently addressed in our pollinator protection guidance. Once the Data Call

- In is iss ued, t he registrant may provide additional information during the waiver request process for the non

conductance of honeybee chronic toxicity guideline for NAA.



### AMVAC Comment : Non

‐ guideline (OECD 234) Honey Bee Larval Acute Toxicity TGAI, naphthalene ace tic acid Non

‐ guideline Honey Bee Larval Chronic Toxicity TGAI, naphthalene acetic acid

The previously mentioned chronic contact study on the Ladybird beetle will provide data that demonstrates that there is no acute toxicity to Ladybird beetle larvae at high doses. This information can then be interpreted to provide a finding that the product will have very low or no toxicity to honey bee larvae.

11 Dal Bosco, C.; Dovzhenko, A.; Liu, X.; Woerner, N.; Rensch, T.; Eismann, M.; Eimer, S.; Hegermann, J.; Paponov, I.A.; Rupert, B.; Heberle

‐ Bors, E.; Touraev, A.; Cohen, J. D.; Palme, K. (2012) The endoplasmic reticulum localized PIN8 is a pollen

‐ specific auxin carrier involved in intracellular auxin homeostasis. Plant J., 71 (5), 1365

‐ 1375.

12 Kim, D. (2014) Acute toxicity of six flower/fruit thinners to Apis mellifera

, Bombus terrestris (Hymenoptera: Apidae) and Osmia cornifrons (Hymenoptera: Megachilidae) in laboratory bioassays. November 17th Meeting of the Entomological Society of America, https://esa.confex.com/esa/2014/webprogram/Paper88333.html12 AMVAC will therefore seek to fulfill th ese requirement s by providing the previously referenced chronic stu dy on Lady beetle larvae (Tsukidate, 2004).


### EFED Response : EFED will review the chronic exposure toxicity study with ladybird beetle mentioned above upon submission by the registrant. However, this non

- guideline test with a different non

- pollinator species of insect may not be adequate to satisfy the honeybee larval acute or chronic toxicity data requirement as related to current OPP policy requirements for pollinator protection. Once the Data Call

- In is issued, t he registrant may provide additional information during the waiver request process to justify the non

- conductance of honeybee larval toxicity guideline for NAA.



### AMVAC Comment : 850.4100 Terrestrial plant toxicity, seedling emergence TGAI, naphthalene acetamide

AMVAC indicated that p revious seedling emergence studies have been conducted with the potassium and ammonium salts of NAA

. For seedling emergence, AMVAC indicated that none of the crops were very sensitive to the potassium salt of NAA. Tomato was the most sensitive species with EC25 s at 0.14, 0.029, and 0.033 lb. a.e./A for plant survival, height, and dry weight, respectively. These rates are a s sociated with chemical applications of greater than 10% of the labeled rate. Studies with ammonium salts, as predicted, produced results that were comparable to that of the potassium salts. The only significant difference was noted for carrots. The ammonium salt EC25 yielded 0.10 and 0.06 ppm for plant height and dry weight, respectively, while the potassium salt was 0.30 and 0.25 ppm, resp ectively. Still, all of these values represent chemical applications of greater than 10% of the labeled rate.

Because the acetamide serves as a rel a tively inactive precursor to NAA and the relative lack of toxicity associated with the NAA salts on seedl ing germination and emergence, AMVAC believes that the studies herein cited should be sufficient for assessing the terrestrial phytotoxicity for NAA and its related products. On this basis, we are seeking a waiver for the requirement to conduct a seedling emergence study on NAA ac et amide.


### EFED Response : Once the Data Call

- In is issued, E FED will review and consider the registrant’s suggestion that earlier studies with products containing ammonium and potassium salts of napthalene are adequate to characteri ze effects from the napthalene acetamide during an official waiver request process. Any additional information to support this claim will also be considered at this time.



### AMVAC Comment : 850.4150 Terrestrial plant toxicity, vegetative vigor TGAI, naphthalene acetamide

Information concerning the vegetative vigor of NAA acetamide at rates greater than 22 ppm are not available; but even this concentration is sufficient to demonstrate that treatment with this chemical would not pose a risk to other te rrestrial plant species. Also, it is generally accepted that13 the biological activity associated with the acetamide only comes about after hydrolysis and production of NAA. The European Commission stated within the Draft Assessment report (DAR) on the aceta mide, “As 1

‐ NAA has significant biological activity as an auxin mimic (and has registered plant protection uses as such), it is therefore assumed that 1

‐ NAA is the active compound and 1

‐ NAD merely a precursor/variant”. Within the upcoming aerobic soil metabolism study that AMVAC has committed to performing, information will be developed that substantiates claims made in the literature that the acetamide is labile in the environment. This has been shown to be the case for other acetamides such as the acy lanilide herbicides, where hydrolysis of the amide functionality is also necessary for activity. For example, propanil is rapidly converted by an aryl acylamidase to produce the active agent 3,4

‐ dichloroaniline (Grover 1990).

The rapid degradation of NAA acetamide in the environment is also evident based on the results of an apple foliar study (Obrist 1994). Within the study, NAA had a half

‐ life of 34.2 hours and NAA acetamide had a half

‐ life of 131.6 hours. Therefore, considering the 14

‐ day interval

assoc iated with standard EPA guideline testing for vegetative vigor, most of the acetamide would be converted to NAA before the test was completed. Given the fact that the active form of the acetamide, NAA in the form of either the potassium or ammonium salt ar e relatively nontoxic to terrestrial plant species, AMVAC believes that the studies herein cited should be sufficient for assessing the terrestrial phytotoxicity for NAA and all of its related products.

Depicker, A. G.; Jacobs, A. M.; Van Montagu, M. C. ( 1988) A negative selection scheme for tobacco protoplastderived cells expressing T

‐ DNA gene 2. Plant Cell reports 7, 63

‐ 66.

Grover, R.; Cessna, A., (1990) Environmental Chemistry of Herbicides, CRC Press. Harnish, W. (1992) K

‐ salt Fruit Fix 800 Tier I no n
‐ target plant hazard evaluation

‐ terrestrial vegetative vigor. ID 22925B006, Unpublished report by Landis Int’l, Inc., AMVAC Report 400

‐ NON

‐ 006.

Harnish, W. (1994a) Fruit Fix Super Concentrate 800 (NAA

‐ ammonium 21.4%): Tier I non

‐ target plant hazard evalu ation

‐ terrestrial vegetative vigor. ID 22925B006, Unpublished report by Landis Int’l, Inc., AMVAC Report 400

‐ NON

‐ 005, MRID 43141101.

Harnish, W. (1994b) K

‐ salt Fruit Fix 800 Tier II non

‐ target plant hazard evaluation

‐ terrestrial vegetative vigor. ID 2292 5B006, Unpublished report by Landis Int’l, Inc., AMVAC Report 400

‐ NON

‐ 075, MRID 43141101.

Harnish, W. (1997) The effect of Amcotone® on tomato under greenhouse conditions. ID 229078001, Unpublished report by Landis Int’l, Inc., AMVAC Report 400

‐ EFF

‐ 006, MRID 4380321.

Obrist, J. J. (1994) NAA bridging study: determination of half

‐ life of naphthaleneacetic acid, (NAA), naphthaleneacetamide, and naphthalene acid, ethyl ester on apple leaves. Report 94399, Unpublished report by Pan Agricultural Labs, Inc., A MVAC Report 400

‐ RES

‐ 002, MRID 4380321.

Rappateur Member State France (2008) Draft Assessment report (DAR):

– public version

‐ Initial risk
assessment provided by the rappateur Member State France for the existing active substance 1

‐ Naphthalenacetamide (1

‐ Naphthaleneacetamide) of the fourth stage of the review programme referred to in Article 8(2) of Council Directive 91/414/EEC, Vol. 3, Annex B, part 6, B.9, August, 2008.14 Shah, J.; Tsui, F.; Klessig, D. F. (1997) Characterization of a salicylic acid

‐ insen sitive mutant (sai1) of Arabidopsis thaliana, identified in a selective screen utilizing the SA

‐ inducible expression of the tms2 gene. Molec. Pl.

‐ Mic. Inter. 10(1) 69

‐ 78.

Sheldrake, A. R. (1973) The production of hormones in higher plants. Bio. Rev. 48, 5 09

‐ 559.

Thomashow, L. S.; Reeves, S.; Thomashow, M. F. (1984) Crown gall oncogenesis: Evidence that a T

‐ DNA gene from the Agrobacterium Ti plasmid pTiA6 encodes an enzyme that catalyzes synthesis of indoleacetic acid. Proc. Natl. Acad. Sci. USA, 81, 5071

‐ 5075. 

### EFED Response : The AMVAC response discusses results from a number of submitted and

non

- submitted open literature studies (listed above ) as justification for waiver of Vegetative Vigor testing with the acetamide. Once a Data Call

- In is issued, EFED will review and consider the registrant’s suggestion that results from earlier studies with products containing ammonium and potassium salts of napthalene are adequate to characterize effects from the napthalene acetamide during an official waiver req uest process. Any additional information to support this claim will also be considered at this time.



### AMVAC Comment : 850.4500 Aquatic Plant Toxicity Testing with F reshwater & Marine Diatom TGAI of naphthalene acetic acid and naphthalene acetamide.

850.4 550 Aquatic Plant Toxicity Testing with Blue

‐ green algae TGAI of naphthalene acetic acid and naphthalene acetamide

Aquatic plant toxicity studies have been conducted with the green algae species, Selenastrum capricornutum . Both the potassium and ammonium salt demonstrated stimulatory and inhibitory effects versus control. The NOEC was observed at 6.44 and 6.47 mg/L (Hughes 1992a and b). These values are well above the predicted levels in surface water of 22.3 ppb associated with the 0.33 lb. a.i./A use rat e for olives. Although different sensitivity may exist for different unicellular aquatic plant species and cyanobacterial species that difference would not likely be extended the several orders of magnitude needed to yield an effect in the environment.

Be cause there is strong evidence that NAA is a growth stimulant with positive effects on algal and diatom systems, there is no reason to believe that exposure would be deleterious to these organisms. Also, the fact that NAA is only anticipated to occur at ve ry low concentrations in the environment, exposure at concentrations that might cause any inhibitory effects is highly unlikely. Given the fact that NAA acetamide is a precursor to NAA, studies for this compound would not yield information of significant v alue. On this basis, AMVAC is requesting waivers for NAA and NAA acetamide for algal and diatom toxicity studies.


### EFED Response : The AMVAC response discusses results from two submitted laboratory studies and several non

- submitted open literature studies w hich discuss plant auxins as stimulants as justification for waiver of further aquatic plant studies. Currently the Agency has only reviewed two studies with end use product s on a single species of algae

. These end use product15 tests are inadequate to add ress hazard for all NAA actives despite arguments to the contrary as expressed in the AMVAC response.

Despite this lack of data, EFED will consider additional information or submitted studies during the formal waiver request process once the Data Call

- I n is issued in order to support an exemption for aquatic plant studies on three species of algae using technical grade active ingredients.