

                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                         WASHINGTON, D.C. 20460      

              OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION
                                       

MEMORANDUM			

March 14, 2012			

SUBJECT:  	Naphthalene Acetates HED Risk Assessment for Section 3 Proposed New Use on Potato Seed Pieces  

PC Code:  056003 (NAA potassium salt) 
DP Barcode: D397387
Decision No.:  427532
Registration No.: 87320-E
Petition No.:  0F7687
Regulatory Action: Section 3
Risk Assessment Type:  Single Chemical Aggregate
Case No.:  0379
TXR No.:  NA
CAS No.:  15165-79-4  (NAA, potassium salt)
MRID No.:  NA
40 CFR: §180. 155

FROM:	Becky Daiss, Biologist 
	Susan Hummel, Chemist
            Abdallah Khasawinah, Toxicologist
	Ivan Nieves, Chemist
            Risk Assessment Branch 4
            Health Effects Division (7509P)

THROUGH:	Elissa Reaves, PhD., Chief
            Risk Assessment Branch 4, HED (7509P)
            Health Effects Division (7509P)
            
TO:		Tony Kish, Chemical Review Manager
		Fungicide Branch
      Registration Division (7505P)

	Attached is Health Effects Division's (HED's) risk assessment of naphthalene acetates for purposes of issuing a Section 3 new use as a seed piece treatment on potatoes.  







1.0 	EXECUTIVE SUMMARY	4

2.0	HED RECOMMENDATIONS	6
2.1	Data Deficiencies	6
2.2	Tolerance Considerations	6
      2.2.1   	Enforcement Considerations 		6
      2.2.2   	International Harmonization 		7
      2.2.3		Recommended Tolerances	7
      2.2.4		Revisions to Petitioned-For Tolerances	7

3.0	INGREDIENT PROFILE	7
3.1	Chemical Identity 	7
3.2	Physical/Chemical Characteristics	9
3.3	Pesticide Use Pattern	9
3.4	Anticipated Exposure Pathways	9
3.5	Environmental Justice	9

4.0	HAZARD CHARACTERIZATION/ASSESSMENT	10
4.1	Toxicology Studies Available for Analysis	10
4.2 	Absorption, Distribution, Metabolism, & Elimination	10
4.3	Toxicological Effects	11
4.4	Safety Factor for Infants and Children	12
	4.4.1 	Completeness of the Toxicology Database	12
      4.4.2 	Evidence of Neurotoxicity	13
      4.4.3 	Evidence of Sensitivity/susceptibility in the Developing or Young	13
      4.4.4 	Residual Uncertainty in the Exposure Data Base	13
4.5	Toxicity Endpoint and Point of Departure	13
	4.5.1 	Dose-Response Assessment	13
      4.5.2 	Recommendation for Combining Exposure Routes	14
      4.5.3	Cancer Classification 	14
      4.5.4 	Summary of Points of Departure Used in Risk Assessment	14

5.0 	DIETARY AND DRINKING WATER RISK ASSESSMENT	15
5.1	Metabolite/Degradate Residue Profile	15
	5.1.1 	Summary of Plant and Animal Metabolism Studies	15
      5.1.2 	Summary of Environmental Degradation	15
      5.1.3 	Comparison of Metabolic Pathways	16
      5.1.4 	Residues of Concern Summary and Rationale	16
5.2	Food Residue Profile	16
      5.2.1	Residues in Crops, Livestock and Poultry	16
      5.2.2	Residues in Processed Commodities	17
5.3	Water Residue Profile	17
5.4	Dietary and Drinking Water Exposure and Risk	17
	
6.0 	RESIDENTIAL EXPOSURE AND RISK	18

7.0 	AGGREGATE EXPOSURE AND RISK ASSESSMENT	19

8.0	CUMULATIVE RISK	19

9.0	OCCUPATIONAL EXPOSURE AND RISK	19
9.1	Exposure Scenarios	19
9.2	Handler Exposure	20
	9.2.1 	Handler Exposure Scenarios	20
      9.2.2 	Handler Exposure Data	21
      9.2.3 	Handler Exposure Assumptions	21
      9.2.4 	Handler Exposure and Risk Estimates	21
9.3	Post Application Exposure	22
	9.3.1 	Post Application Exposure Scenarios	22
      9.3.2 	Post Application Exposure Assumptions	22

10.0	REFERENCES	23

Appendix A. Toxicity Profile and Executive Summaries	24
	A.1  	Toxicity Data Requirements	24
	A.2  	Toxicity Profiles	30
	A.3 	Hazard Identification and Endpoint Selection	33
	A.4  	Executive Summaries	35
Appendix B. Physical/Chemical Properties	51
Appendix C. Review of Human Research	52




1.0  	EXECUTIVE SUMMARY

	This assessment provides information to support the issuance of a Section 3 proposed new use of 1-naphthaleneacetic acid, potassium salts in/on potatoes.  The risk assessment process considers the human health effects of pesticides and incorporates a reassessment of tolerances (pesticide residue limits in food) to ensure that they meet the safety standard established by the Food Quality Protection Act (FQPA) of 1996. 

Use Profile 

Registered Uses
	
	1-Naphthaleneacetic acid, its salts, ester, and acetamide are plant growth regulators which are collectively referred to as naphthalene acetates (NAA).  They are currently registered for use on various orchard and fruit crops and ornamentals.  Naphthalene acetates currently have tolerances in/on a number fruit commodities ranging from 0.05 ppm to 0.15 ppm 40CFR§180.155.  Naphthalene acetates are used to stimulate growth, delay flower induction and leaf drop, prevent preharvest fruit drop, thin fruit, and control sprout formation.  Registered formulations include dust, wettable powder, flowable concentrate, emulsifiable concentrate, soluble concentrate, and liquid ready-to-use.  Thinning and stop drop formulations containing 1- naphthaleneacetic acid or its ammonium, potassium, or sodium salts are applied using ground spray or aerial equipment.  Formulations for control of sprout formation containing the ester and/or acetamide of 1- naphthaleneacetic acid are applied by hand held sprayer and paint brush.  NAA containing products used to stimulate root growth are applied as a dilute root dip or soil drench.  The plant growth regulating activity of naphthalene acetates is due to structural similarity to the natural plant hormone indole acetic acid (IAA), the most common naturally occurring auxin.  IAA promotes growth in excised plant organs, induces adventitious roots, inhibits axillary bud growth, and regulates gravitropism.  Homeowner applications are limited use on ornamental plants.

Proposed New Use

	Stehekin, LLC requested a Section 3 registration of Rejuvenate(TM)  Seed Treatment for use as a seed piece treatment on potatoes.  Renew(TM) Concentrate is a soluble concentrate formulation containing 6.25% NAA, potassium salt.  The maximum seed piece treatment rate Stehekin, LLC is 0.25 g ai/A on seed.  The proposed application rate is based on the registrant's theoretical calculation of maximum potential residues at this rate showing residues less than the LOQ, in lieu of residue chemistry data. The proposed potato use does not include homeowner use or application to residential areas.

Hazard Identification

      The toxicology data base is adequate to characterize the toxicity of the naphthalene acetates.  All six chemicals that comprise the naphthalene acetates are combined for the toxicity assessment for this RED because they are structurally related and are metabolized to the acid form and eliminated from the body as glycine and glucuronic acid conjugates within 48 hours after exposure.  Naphthalene acetates have low acute toxicity via the oral, inhalation and dermal  routes of exposure. NAA is not a skin irritant or a dermal sensitizer.  The NAA acid and its sodium salt were found to be irritating to the eye, but the NAA ethyl ester was not an eye irritant. The NAA acetamide was found to be an eye irritant in one old test and a non-eye irritant in another study conducted on the currently produced material.
      
      Repeated exposure oral toxicity studies in rats and dogs resulted in decreased body weights and body weight gains accompanied by decreased food consumption.  The major target organs of subchronic and chronic oral exposure were the liver, stomach and lung.  Repeated oral exposure also resulted in decreased hematocrit and hemoglobin along with reduced RBC count in rats and dogs and hypocellularity of the bone marrow in dogs.  There was no developmental toxicity at highest doses of NAA tested in the rat or in the rabbit, but developmental toxicity (decreased fetal weight and minor skeletal changes) were seen in rats orally gavaged with the sodium salt.  Reproductive effects of NAA sodium salt occurred at relatively high doses and were limited to reduced litter survival and pup weight throughout lactation in both generations of offspring in a two generation reproduction study.  Carcinogencity studies of NAA acetamide in mice and NAA sodium salt in rats and mice are considered adequate for the evaluation of the oncogenicity of the NAA group.  In these three studies the tested NAA compounds were not carcinogenic in mice or rats. 

Dose Response Assessment

      Toxicological endpoints were selected for dietary/drinking water and occupational exposure scenarios.  There were no toxicological effects attributable to a single exposure of NAA observed in oral toxicity studies.  Therefore, a POD for acute dietary exposure was not selected.  A chronic RfD was selected from a chronic toxicity study in dogs based on stomach lesions and liver effects in males.  A toxicological point of departure (POD) for dermal exposures was selected from a dermal toxicity study in rats based on reduced body weight gain and food efficiency at the highest dose tested.  A short-term inhalation exposure POD was selected from a developmental toxicity study in rats based on decreased body weight gain.  An intermediate-term inhalation exposure POD was selected from a subchronic oral dog study based on based on  GI tract and bone marrow effects.  An uncertainty factor of 100X was applied to endpoints selected for exposure routes (10x for interspecies extrapolation, 10x for intraspecies variation).   
      
Exposure/Risk Assessment and Risk Characterization

	Risk assessments were conducted for dietary (food and water) and occupational exposure pathways based on registered uses and requests for a new use of NAA salts on potato seed pieces.  Screening level acute and chronic dietary and drinking water risk assessments for naphthalene acetates conclude that dietary and drinking water exposure estimates are below HED's level of concern the general population and all population subgroups.  Worker exposures were assessed for handler and post-application activities.  Occupational exposure and risk estimates indicate that worker handler and post-application exposures are not of concern at the maximum proposed application rate for the proposed new use.

Use of Human Studies

	This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical.  These studies, listed in Appendix 1.0, have been determined to require a review of their ethical conduct.  Some of these studies are also subject to review by the Human Studies Review Board.  All of the studies used have received the appropriate review.

2.0	HED RECOMMENDATIONS

2.1 	Data Deficiencies

	There are no residue chemistry issues that would preclude granting registration for the requested seed piece treatment use of NAA on potatoes.  However, the following studies will be required if the registrant requests future uses at a higher application rate. 

   oo A metabolism study (preferably on a root crop) must be submitted if a higher rate or foliar use is later proposed.

   oo No processing study is required at the present time.  Processing studies for potatoes must be submitted if a higher rate or foliar use is proposed.  A 5x exaggerated rate is suggested.

   oo No confined rotational crop study is required at the present time.  A confined rotational crop for potatoes must be submitted if a higher rate or foliar use is proposed.  An exaggerated rate is recommended.

   oo Method NAA-AM-001 and Method NAA-AM-002 will be submitted to ACL/BEAD  and to FDA for updating PAM II. 
      
   oo Immunotoxicity and acute and subchronic neurotoxicity studies are required as part of new 40 CFR Part 158 data requirements for registration of a pesticide.
      
2.2	Tolerance Considerations
	
2.2.1 	Enforcement Analytical Method

	An acceptable enforcement method is available for residues of NAA and salts in potatoes.  HPLC methods (Method NAA-AM-001 and Method NAA-AM-002) for determination of NAA in plant commodities have been submitted and reviewed. These methods have been subjected to successful independent laboratory validations. Acceptable recoveries were obtained from apples, olives and olive oil fortified with NAA at the method limit of quantitation (LOQ; 0.01 ppm) and at 1.0 ppm.  These methods will be submitted to ACL/BEAD and to FDA for updating PAM II. These methods are an improvement of the existing enforcement methods in PAM II.  Samples of potato tuber from the submitted field trials were analyzed for residues of NAA using Method NAA-AM-002.  Acceptable method validation and concurrent method recoveries were achieved with potato tubers fortified at 0.01 ppm and 0.50 ppm.

2.2.2 	International Harmonization

	No Codex, Canadian, or Mexican maximum residue limits (MRLs) have been established for residues of NAA, its salts, ester, and acetamide on potatoes.

2.2.3 	Recommended Tolerances

      The petitioner has requested an exemption from the requirement of a tolerance for residues of NAA potassium salts in/on potatoes.  However, a tolerance at the LOQ is needed because some available data suggest the potential for residues below the LOQ and toxicological endpoints have been selected for dietary exposure based on available toxicity data for NAA.  HED recommends that a tolerance be established for NAA residues in/on potatoes at the LOQ of 0.01 ppm, providing the theoretical calculations are clarified and the label is changed as provided below.  

      There are no residue chemistry issues that would preclude granting registration for the requested seed piece treatment use of NAA on potatoes or establishment of a tolerance for the combined residues of 1-naphthaleneacetic acid and its conjugates calculated as 1-naphthaleneacetic acid from the application of 1-naphthaleneacetic acid, its ammonium, sodium, or potassium salts, ethyl ester, and acetamide in/on potatoes at 0.01 ppm. 
      
Table 1. Tolerance Recommendation
                            Crop Group or Commodity
                           Proposed Tolerance (ppm)
                          Recommended Tolerance (ppm)
Comments; Correct Commodity Definition
Potato
                                   Exemption
                                     0.01


2.2.4	Revisions to Petitioned-For Tolerances

	The registrant proposed an exemption from the requirement of a tolerance.  HED recommends establishment of a tolerance of 0.01 ppm for potato. 

3.0	INGREDIENT PROFILE 

3.1  	Chemical Identity

	The nomenclature for NAAs is provided in Table 2.









Table 2. NAA Nomenclature
Chemical structure




Common name
                                 NAA acetamide
                                      NAA
Molecular Formula
                                   C12H11NO
                                   C12H10O2
Molecular Weight
                                    185.23
                                    186.20
IUPAC name
                            2-(1-naphthyl)acetamide
                           2-(1-naphthyl)acetic acid
CAS name
                            1-naphthaleneacetamide
                           1-naphthaleneacetic acid
CAS #
                                    86-86-2
                                    86-87-3
PC Code
                                    056001
                                    056002
Chemical structure




Common name
                              NAA potassium salt
                               NAA ammonium salt
Molecular Formula
                                   C12H10O2K
                                   C12H13NO2
Molecular Weight
                                    224.31
                                    203.24
IUPAC name
                         potassium-2(1naphthyl)acetate
                         ammonium-2(1naphthyl)acetate
CAS name
                  1-naphthalnene acetic acid, potassium salt
                    1-naphthaleneacetic acid, ammonium salt
CAS #
                                  15165-79-4
                                  25545-89-5
PC Code
                                    056003
                                    056004
Chemical structure




Common name
                                NAA sodium salt
                                NAA ethyl ester
Molecular Formula
                                  C12H10O2Na
                                   C14H14O2
Molecular Weight
                                     208.2
                                    214.26
IUPAC name
                          sodium-2(1naphthyl)acetate
                           ethyl-2(1naphthyl)acetate
CAS name
                     1-Naphthaleneacetic acid, sodium salt
                     1-Naphthaleneacetic acid, ethyl ester
CAS #
                                    61-31-4
                                   2122-70-5
PC Code
                                    056007
                                    056008

3.2 	Physical/Chemical Characteristics

      A detailed description of the physiciochemical properties of NAA is provided in Appendix C.   Based on the limited available for data NAA exhibits relatively low solubility in water and higher solubility in solvents. It has a relatively high vapor pressure (0.3 mmHg).  NAA is relatively mobile but short lived in terrestrial and aquatic environments.  NAA does not present significant concerns for bioaccumulation based on measured bioconcentration factors. 

3.3	Pesticide Use Pattern  

	Stehekin, LLC has submitted a Section 3 request for registration of Renew(TM) Concentrate for use as a seed piece treatment on potatoes.  Rejuvenate Seed Treatment(TM) is a soluble concentrate formulation containing 6.25% NAA, potassium salt. The use pattern for the proposed new use is provided in Table 3.

Table 3.  Summary of Directions for Use of NAA, Potassium Salts
Application Type 
                                  Formulation
                                       
                                 Applic. Rate 
                                  (g ae[1]/A)
                          Max. No. Applic. per Season
                          Max. Seasonal Applic. Rate
                                   (lb ai/A)
                                      PHI
                                    (days)
                                Russet Potatoes
Seed piece treament
                          6.25% NAA, potassium salt.
                                     0.25
                                 Not provided
                                Not applicable
                                Not applicable

Use Directions and Limitations:  Apply in enough water to ensure adequate coverage, but without damaging the seed piece.  
                          Other Varieties of Potatoes
Seed piece treament
                          6.25% NAA, potassium salt.
                                     0.18
                                 Not provided
                                Not applicable
                                Not applicable

Use Directions and Limitations:  Apply in enough water to ensure adequate coverage, but without damaging the seed piece.  
[1] ae = acid equivalent

3.4	Anticipated Exposure Pathways

	Dietary (food and water) and occupational exposures via dermal and inhalation pathways are expected based on proposed uses of NAA as a seed treatment and foliar spray on potatoes.  There are no residential uses for NAA resulting in exposure to children via incidental oral activities.   

3.5	Environmental Justice

      Potential areas of environmental justice concerns, to the extent possible, were considered in this human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations," http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf).

      As a part of every pesticide risk assessment, OPP considers a large variety of consumer subgroups according to well-established procedures.  In line with OPP policy, HED estimates risks to population subgroups from pesticide exposures that are based on patterns of that subgroup's food and water consumption, and activities in and around the home that involve pesticide use in a residential setting.  Whenever appropriate, non-dietary exposures based on home use of pesticide products and associated risks for adult applicators and for toddlers, youths, and adults entering or playing on treated areas postapplication are evaluated.  Further considerations are currently in development, as OPP has committed resources and expertise to the development of specialized software and models that consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary patterns among specific subgroups.  

4.0	HAZARD CHARACTERIZATION/ASSESSMENT

4.1	Toxicology Studies Available for Analysis
      
      Based on structural activity relationship and metabolism data, all forms of NAA are expected to exhibit similar toxicological effects.  Therefore the Agency concluded that required toxicity testing on any form should serve for all members of this group of chemicals. The toxicity database for NAA is sufficient for a full hazard evaluation and is considered adequate to evaluate risks to infants and children.  Acceptable developmental toxicity studies in the rat and rabbit and an acceptable reproduction study in the rat are available.  Based on the results of the available toxicity studies, there is no evidence for neurotoxicity or immunotoxicity.  However, in accordance with the revised 40 CFR Part 158 Toxicology Data Requirements, a Neurotoxicity Battery (870.6200a and b) and an Immunotoxicity study (870.7800) are required.  A subchronic inhalation toxicity study is not available but is not required based on results of the occupational exposure assessment which indicates that use of an oral endpoint provides an ample margin of safety to account for any uncertainties in route to route extrapolation (i.e., MOEs > 650,000).   

4.2	Absorption, Distribution, Metabolism and Excretion

	The absorption, distribution metabolism and excretion of NAA were studied in rats.  In one study, rats were given either a single 1 or 100 mg/kg bw oral dose, or a 14-day repeated dose (1 mg/kg/day) of [[14]C] ring labeled -1-naphthaleneacetamide.  Recovery of administered radioactivity was 97-101%. 1-Naphthaleneacetamide was readily absorbed and excreted within 36 hours.  Urinary excretion accounted for 66-74% of the administered radioactivity for single and repeat doses.  Repeat did not appreciably affect the absorption/excretion processes.  Excretion via the feces accounted for the remainder of the administered radioactivity in all treatment groups.  Urinary metabolism involved amide cleavage followed by glycine conjugation with the glycine conjugate being the major metabolite of the low and repeat doses (14-47%). The glucuronide conjugate was also a major metabolite at the low doses (4.5-7%).  For feces, the major metabolite detected was the dihydrodiol of naphthaleneacetamide (4-11%).  Parent compound was detected at low concentrations (1-2% of administered) only in feces.  In another study, rats were given either a single 1 or 100 mg/kg bw oral dose, or a 14-day repeated dose (1 mg/kg/day) of [[14]C] ring labeled 1-naphthaleneacetic acid, ethyl ester. Recovery of administered radioactivity was 99-101%. 1-Naphthaleneacetic acid, ethyl ester was readily absorbed and excreted within 36 - 48 hours following a single and repeat doses.  Urinary excretion accounted for 68-85% of the administered radioactivity following single or multiple oral low doses and 62-78% following a single high dose.  Excretion via the feces accounted for the remainder of the administered radioactivity excreted by all treatment groups. At the high dose, glucuronide conjugation appeared to play a more important role following ester cleavage.  Parent compound was detected at low concentrations (0.5-5% of administered) only in feces.  For both studies, excretory patterns exhibited no gender-related variability for the low dose groups and only minor gender difference at the high dose.  Excretion patterns of the high-dose group reflected delayed absorption.  Tissue burdens of parent and metabolites were very low at termination for both studies.  Most components in the matrices examined (urine and feces) were adequately quantified and characterized.  

      The metabolism studies of the acid and its acetamide and the ethyl ester in animals provide supporting evidence that the toxicity of these various forms of NAA would be similar since all are metabolized to the acid form and eliminated from the body as glycine and glucuronic acid conjugates within 36 to 48 hours of initial exposure.

4.3   	Toxicological Effects
	
      The major target organs of repeated oral exposure of NAA to rats, dogs and mice were the liver (enlarged liver, increased liver weight with histopathological changes: vacuolation of the periportal hepatocytes, pericholangitis, sinusoidal histiocytosis in dogs) stomach (mucosal gland dilation), lung (focal alveolar macrophages).the liver, stomach and lung.  Repeated oral exposure also resulted in decreased hematocrit and hemoglobin along with reduced RBC count in rats and dogs and hypocellularity of the bone marrow in dogs. 

	There was no developmental toxicity at highest doses of NAA tested in the rat or rabbit, but developmental toxicity (decreased fetal weight and minor skeletal changes) were seen in rats orally gavaged with the sodium salt. Reproductive effects of NAA sodium salts included reduced litter survival and pup weight throughout lactation in both generations of offspring in a two generation reproduction study.  

	NAA and its acetamide and the ethyl ester were tested for mutagenic effects in a gene mutation bacterial assay, mouse lymphoma assay, and mouse erythrocyte micronucleus assay and were not mutagenic.  Additionally NAA was tested for mitotic gene conversion and dominant lethality in rats and found to be negative.  A published NCI carcinogenicity study of NAA acetamide in mice and a guideline chronic/oncogenicity study of NAA sodium salt in rats and mice are considered adequate for the evaluation of the oncogenicity of the NAA group.  In these three studies the tested NAA compounds were not carcinogenic in mice or rats. 
	
      Naphthalene acetates have low acute toxicity via the oral (Toxicity Category III), inhalation (Toxicity Category IV), and dermal (Toxicity Category III) routes of exposure.  NAA is not a skin irritant (Toxicity Category IV).  It is not a dermal sensitizer.  The NAA acid and its sodium salt were found to be irritating to the eye, but not the NAA ethyl ester (Category IV).  The NAA acetamide was found to be an eye irritant in one old test and a non-eye irritant in another recent study conducted on the currently produced material.

4.4	Safety Factor for Infants and Children (FQPA Safety Factor)

      The FQPA factor for increased susceptibility to infant and children is reduced to 1x based on the following considerations.  The toxicology data base for NAA is nearly complete and adequate for assessing increased susceptibility under FQPA.  In the recently submitted developmental toxicity study conducted with NAA sodium salt in rats (MRID 46685803) fetal toxicity (mainly decreased fetal weights and minor skeletal changes) was observed at a dose lower than the maternally toxic dose.  However, there were clear NOAELs in this developmental study and the point of departures used in the chronic dietary assessment (15 mg/kg/day) are protective of the fetal effects observed in the developmental study.    There are no residual uncertainties in the exposure database. The dietary risk assessment is conservative and will not underestimate dietary exposure to NAA.
      
      An immunotoxicity study is required as a part of new data requirements in the 40 CFR Part 158 for conventional pesticide registration.  However, the toxicology database for NAA does not show any evidence of treatment-related effects on the immune system and the overall weight of evidence suggests that this chemical does not directly target the immune system.  Consequently, the Agency does not believe that conducting a functional immunotoxicity study will result in a lower POD than that currently used for overall risk assessment, and therefore, a database uncertainty factor (UFDB) is not needed to account for lack of this study.
      
      Acute and subchronic neurotoxicity studies are required as a part of new data requirements in the 40 CFR Part 158 for conventional pesticide registration.  However, the Agency does not believe that conducting a neurotoxicity battery will result in lower PODs than those currently used for overall risk assessment or that a database uncertainty factor (UFDB) is needed to account for lack of these studies based on the following considerations.  The acute oral toxicity studies of the various salts are all Category III or IV.  The toxicity database does not show any indications of neurotoxicity or neuropathology (the liver, stomach, lung, and hematological parameters are the target organs based on repeat toxicity studies in rats, mice, and dogs).  A screening level assessment of acute dietary exposure, conducted using the chronic RfD as a highly conservative POD, indicates that acute dietary risks are not of concern.
      
4.4.1	Completeness of the Toxicology Database
	
      The toxicity database for NAA is sufficient for a full hazard evaluation and is considered adequate to evaluate risks to infants and children.  Acceptable developmental toxicity studies in the rat and rabbit and an acceptable reproduction study in the rat are available. Acute and subchronic neurotoxicity and immunotoxicity studies are required as part of new 40 CFR Part 158 data requirements for registration of a pesticide. 
2.0.2 Evidence of Neurotoxicity
    
        There are no neurotoxicity studies available but the chronic and subchronic studies show no evidence of neurotoxicity or neuropathology.  
    
4.4.3	Evidence of Sensitivity/Susceptibility in the Developing or Young Animal
      
      There is low concern (and no residual uncertainty) for pre- and/or postnatal toxicity resulting from exposure to the NAA group of chemicals.  Although the rat developmental study showed quantitative susceptibility with lower fetal NOAELs than maternal NOAELs, the chronic dietary point of departure is protective of this study.  There was no indication of increased susceptibility (quantitative or qualitative) to rabbits to in utero exposure to naphthalene acetates or to pre and post-natal exposure in rat reproduction studies.   

4.4.4	Residual Uncertainty in the Exposure Database 	

		There are no residual uncertainties in the exposure database.  The dietary risk assessment is conservative and will not underestimate dietary exposure to NAA.
4.5	Toxicity Endpoint and Point of Departure

	4.5.1	Dose-Response Assessment

	Toxicity endpoints and points of departure (PODs) for dietary (food and water), occupational, and residential exposure scenarios are summarized below.  A detailed description of the studies used as a basis for the selected endpoints are presented in Appendix A.  

	There were no toxicological effects attributable to a single exposure of NAA observed in oral toxicity studies.  Therefore, a POD for acute dietary exposure was not selected.  A chronic POD of 15 mg/kg/day (NOAEL) was selected from a chronic feeding study in dogs with 1-Naphthaleneacetic acid, sodium salt oral feeding study in based on stomach lesions in 75% of the males and by slight sinusoidal histiocytosis in the liver of 50% of the males at the LOAEL of 75 mg/kg/day.  A UF 100x (10x to account for interspecies extrapolation and 10x for intraspecies variation) was applied to the dose to obtain a chronic reference dose (cRfD/cPAD) of 0.15 mg/kg/day.  

	A NOAEL of 300 mg/kg/day was selected for short-term and intermediate term dermal exposure POD based on a subchronic dermal toxicity in rats which showed reduced body weight gain and food efficiency at the LOAEL of 1000 mg/kg/day.  Due to a lack of inhalation studies, a POD from an oral prenatal developmental study in rats was selected for inhalation risk assessments: a POD for maternal toxicity of 50 mg/kg/day (NOAEL) was selected for short-term inhalation exposure based on decreased body weight gain during the compound administration at 250 mg/kg/day.  A NOAEL of 25 mg/kg/day was selected for intermediate-term inhalation exposure from a subchronic dog study based on lesions of the GI tract and hypocellularity of the bone marrow.  An absorption factor of 100% is applied for inhalation exposures.  The level of concern (LOC) or margin of exposure (MOE) for dermal and inhalation exposures is 100 based on uncertainty factors of 10x for intraspecies variability and 10x for interspecies sensitivity.  For short-term exposure risk assessments, the dermal and inhalation exposure routes can be combined due to the common toxicity endpoint (reduced body weight gain) via the dermal and inhalation (oral equivalent) routes. 

4.5.2	Recommendations for Combining Exposure Routes

      When there are potential residential exposures to the pesticide, aggregate risk assessment must consider exposures from three major sources: oral, dermal and inhalation exposures.  Exposures via the oral, dermal and inhalation routes cannot be combined for short-term assessments because oral exposure endpoints are not based on toxicological effects common to either dermal or inhalation endpoints (i.e., the chronic oral endpoint is based stomach lesions and liver effects; short-term inhalation and dermal endpoints are based on body weight effects).  

4.5.3	Cancer  Classification

	A guideline study for the oncogenicity of NAA in mice is not available.  However published NCI carcinogenicity study of NAA acetamide in mice, a guideline chronic/oncogenicity study of NAA sodium salt in rats, and a chronic/oncogenicity study of NAA sodium salt mice are considered adequate for the evaluation of the oncogenicity of the NAA group.  In these three studies the tested NAA compounds were not carcinogenic in mice or rats.

4.5.4	Summary of Points of Departure Used in Risk Assessment

A summary of the endpoints selected by HED toxicologists is provided below and in Tables 4 and 5.
      
Table 4. Summary of Toxicological Endpoints for Naphthalene Acetates  for Use in Dietary Human Health Risk Assessments
Exposure/Scenario
                              Point of Departure
                        Uncertainty/FQPA Safety Factors
                       RfD, PAD, LOC for Risk Assessment
                        Study and Toxicological Effects
                                       
                                       
Acute Dietary
(General Population)
An acute RfD for the general population or any population subgroups was not selected because no effect attributable to a single (or few) day(s) oral exposure was observed in animal studies.
Chronic Dietary 
(All Populations)
NOAEL = 15 mg/kg/day
UFA= 10x
UFH=10x
FQPA SF= 1x
Chronic RfD = 0.15
mg/kg/day
cPAD = 0.15 mg/kg/day
Chronic Toxicity - Dog;
LOAEL = 75 mg/kg/day based on stomach lesions in 75% of the males and by slight sinusoidal histiocytosis in the liver of 50% of the males.  
Incidental Oral 
Dermal
Inhalation
There are no residential uses for or exposures to the proposed use of naphthalene acetic acid ethyl ester.  Therefore exposure endpoints are not required and not selected for residential exposure assessment.   
Cancer (all routes)
A "not likely" human carcinogen
Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and  used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures.  NOAEL = no observed adverse effect level.  LOAEL = lowest observed adverse effect level.  UF = uncertainty factor.  UFA = extrapolation from animal to human (interspecies).  UFH = potential variation in sensitivity among members of the human population (intraspecies).  UFL = use of a LOAEL to extrapolate a NOAEL.  UFS = use of a short-term study for long-term risk assessment.  UFDB = to account for the absence of key date (i.e., lack of a critical study).  FQPA SF = FQPA Safety Factor.  PAD = population adjusted dose (a = acute, c = chronic).  RfD = reference dose.  MOE = margin of exposure.  LOC = level of concern.  N/A = not applicable.

Table 5.  Summary of Toxicological Doses and Endpoints for NAA  for Use in Occupational Human Health Risk Assessments
Exposure/
Scenario
Point of Departure
Uncertainty Factors
Level of Concern for Risk Assessment
Study and Toxicological Effects
Dermal Short Term (1-30 days) and Intermediate (1-6 months) 
NOAEL= 300 mg/kg/day
UFA= 10x
UFH=10x

Occupational LOC for MOE = 100
Dermal Toxicity Study - Rat 
LOAEL = 1000 mg/kg/day based on reduced body weight gain and food efficiency
Inhalation Short Term (1-30 days) 
NOAEL= 50 mg/kg/day
UFA= 10x
UFH=10x

Occupational LOC for MOE = 100
Developmental Toxicity Study - Rat 
Maternal LOAEL = 250 mg/kg/day based on based on decreased body weight gain during the gestation period.  
Inhalation Intermediate Term (1-6 months) 
NOAEL= 25 mg/kg/day
UFA= 10x
UFH=10x

Occupational LOC for MOE = 100
Subchronic Study -Dog
LOAEL for systemic toxicity =150 mg/kg/day based on lesions of the GI tract and hypocellularity of the bone marrow.
Cancer (all routes)
A "not likely" human carcinogen

5.0	DIETARY AND DRINKING WATER EXPOSURE AND RISK ASSESSMENT

5.1 	Metabolite/Degradate Residue Profile

5.1.1	Summary of Plant and Animal Metabolism Studies

	The qualitative nature of the residue in plants and ruminants resulting from registered uses of naphthalene acetates is adequately understood based on apple, olive, and goat metabolism studies.  Based on guideline requirements, plant metabolism studies should be conducted for a minimum of three diverse crops to determine the qualitative metabolic fate of the active ingredient (OPPTS GLN 860.1300).  Although metabolism data are not available to a commodity similar to potatoes, a 3[rd] diverse metabolism study will not be required for the current petition.  However, if other uses are proposed on crops other than fruit crops, tree nuts, or fruiting vegetables or at a higher application rate on potatoes, a metabolism study (preferably on a root crop) will be needed. 

5.1.2	Summary of Environmental Degradation

	NAA appears to be generally short lived, based on measured and modeled values.  It should degrade by means of a combination of both biotic and abiotic processes.  The reported half-life for NAA of 10 days was attributed to microbial degradation.  NAA is mostly ionized in the environment so would partition preferentially with the water.  The environmental fate characteristics of the salts of NAA are expected to be similar to those of the acid.  In the environment, the NAA salts will rapidly dissociate to 1-naphthalene acetate anion and its corresponding cation.  Based on its pKa, NAA is expected to exist mostly as the anion in normal environmental conditions.  Anions generally do not adsorb to organic carbon and clay more strongly than their neutral counterparts.  Volatility may be an important route of dissipation for NAA under various environmental conditions based on NAA's relatively high measured and estimated vapor pressures (0.3 mmHg).  NAA ethyl ester is susceptible to hydrolysis at high pHs.  The product of NAA ethyl ester hydrolysis is NAA.  NAA in aqueous solution appears to be unstable to sunlight irradiation.  Upon exposure to sunlight, gaseous phase NAA reaction with hydroxyl (OH) radicals should proceed with a half-life of around 0.3 days.  NAA is mobile to moderately mobile according to the FAO mobility classification.  For NAA measured bioconcentration factors (BCFs) of only 0.15-0.59 and <1.7-4.2 were observed in carp (Cyprinus carpio) at test chemical concentrations of 0.5 and 0.05 mg/L, respectively.  These values suggest a low potential of bioconcentration for NAA.

      There are considerable uncertainties in this assessment due to the lack of measured data.  Most of the environmental fate characteristics available for NAA are derived from structure activity relationships.  Furthermore, there is lack of information about possible degradates of NAA.

 5.1.3 	Comparison of Metabolic Pathways
 
      Metabolism studies in animals of the NAA, its acetamide, and the ethyl ester in animals indicate that all forms are metabolized to the acid form and eliminated from the body as glycine and glucuronic acid conjugates within 36 to 48 hours of initial exposure.  Studies show that NAA salts and esters are converted to the acid form and conjugates of the acid form.
      
4.1.4 Residues of Concern Summary and Rationale
       
      Residues of concern were determined by the HED risk assessment team for NAA.  The terminal residues of concern in plants and ruminants are the parent compounds, NAA and its conjugates, based on apple, olive, and goat metabolism studies.  (D293239, G. Otakie, November 18, 2003).    

Table 6.  NAA Residues of Concern in Plants and Ruminants.
Matrix
Residues of Concern

For Risk Assessment
For Tolerance Expression
Plants
Primary and Rotational crops
NAA and Conjugates
NAA and Conjugates
Livestock
Ruminant and Poultry
NAA and Conjugates
NAA and Conjugates
Drinking Water
NAA and Conjugates
NA

5.2	Food Residue Profile
    
1.1.1 Residues in Crops, Livestock and Poultry

      In lieu of providing field trial data for their proposed seed piece treatment, Stehekin, LLC, , through their consultant, Spring Trading Company submitted a theoretical calculation to show that residues of NAA on potatoes will be less than the LOQ.   The petitioner originally requested an application rate of 0.25 lb ai/A for all types of potatoes based on their theoretical calculation which assumed a potato yield of about 550 cwt/A. Statistical data in a National Potato Council (NPC) publication (at www.NationalPotatoCouncil.org) were submitted to support the yield assumption.  However, based on EPA's analysis of NCP yield data the petitioner's theoretical calculation (based on a potato yield of about 550 cwt/A) will support use of NAA as a seed piece treatment on potatoes in the Pacific Northwest only, or on Russet potatoes only (75% or more of the potatoes produced in the Pacific Northwest are Russets). An application rate for NAA of 0.25 lb ae/A can be supported on Russet potatoes only.  An application rate for NAA of  0.18 lb ae/A can be supported for all potatoes based on a theoretical calculation showing residues less than the LOQ.
      Based on livestock feedstuffs associated with proposed and registered uses, the dietary burdens to livestock are 0.25 ppm for beef cattle and 0.13 ppm for dairy cattle. These burdens are considered tentative, but conservative, because citrus and potato processing data are not available.  At this time, the Agency has determined that NAA is in Category 6(a)(3) (i.e., no reasonable expectations of finite residues of concern in meat and milk).  This tentative conclusion is reserved pending submission of the required processing studies and a determination of the magnitude of the residues in citrus and potato processed commodities. When the requested processing data are submitted, the Agency will re-evaluate NAA's Category 3 determination, and if necessary re-calculate the estimated dietary burden for ruminants.

5.2.2	Residues in Processed Commodities

      Residue data for processed commodities associated with potatoes are needed.  Since residues in the available field trials using the maximum proposed rate are near the LOQ, the processing study should be conducted using field trials treated at an exaggerated application rate.

5.3	Water Residue Profile 

	The Environmental Fate and Effects Division (EFED) calculated conservative, Tier I Estimated Drinking Water Concentrations (EDWCs) of naphthalene acetates in ground water and surface water for use in the human health risk assessment.  EDWCs for 1-naphthaleneacetic acid were calculated using FIRST (surface water) and SCIGROW (ground water) drinking water models.  These values generally represent upper-bound estimates of the concentrations of 1-naphthaleneacetic acid equivalents that might be found in surface and ground water due to the use of 1-naphthaleneacetic acid on olives, which represents the highest single application rate.  Both models provide estimates suitable for screening purposes.  Modeled EDWCs for peak and average concentrations of naphthalene acetates in surface water are 0.02 and 0.003 ppm respectively.  The modeled peak and average EDWCs for groundwater is 0.00002 ppm.  

 5.4 	Dietary and Drinking Water Exposure and Risk

	A conservative chronic dietary and drinking water exposure and risk assessment was conducted using the Dietary Exposure Evaluation Model with the Food Commodity Intake Database (DEEM-FCID(TM)).   Dietary risk assessment incorporates both exposure and toxicity of a given pesticide.  For dietary assessments, the risk is expressed as a percentage of a maximum acceptable dose (i.e., the dose which HED has concluded will result in no unreasonable adverse health effects).  This dose is referred to as the population adjusted dose (PAD).  The PAD is equivalent to the POD divided by the uncertainty factors. For acute and non-cancer chronic exposures, HED is concerned when estimated dietary risk exceeds 100% of the PAD.  

	Conservative chronic dietary naphthalene acetates exposure and risk estimates resulting from food intake were determined for the general U.S. population and various population subgroups.  The naphthalene acetates chronic dietary and drinking water exposure assessment was conducted using the Dietary Exposure Evaluation Model software with the Food Commodity Intake Database (DEEM-FCID(TM), Version 1.3), which incorporates consumption data from USDA's Continuing Surveys of Food Intakes by Individuals (CSFII), 1994-1996 and 1998. The dietary risk assessment incorporates both exposure and toxicity of naphthalene acetates.  For acute and chronic assessments, the risk is expressed as a percentage of a maximum acceptable dose (i.e., the dose which HED has concluded will result in no unreasonable adverse health effects).  This dose is referred to as the population adjusted dose (PAD).  The PAD is equivalent to the Reference Dose (RfD) divided by the special FQPA Safety Factor.  HED is concerned when estimated dietary risk exceeds 100% of the PAD.  

	The chronic dietary and drinking water exposure/risk analyses for all supported naphthalene acetates food uses was conducted using conservative, Tier 1 exposure assessments.  The Tier I analyses assume tolerance level residues for all registered uses, 100%  crop treated for all commodities with existing tolerances, and default processing factors.  The chronic analysis incorporated the annual year average surface drinking water estimate of 0.003 ppm from application of NAA to olives.  Based on analyses of estimated dietary risks for the general U.S. population and various population subgroups, the chronic dietary exposure estimates for naphthalene acetates are significantly below HED's level of concern for all supported commodities (Table 7).  

Table 7.  Summary of Chronic Dietary Exposure and Risk for NAA
                              Population Subgroup
                               cPAD (mg/kg/day)
                                    Chronic
                                       
                                       
                             Exposure (mg/kg/day)
                                    % cPAD
General U.S. Population
                                     0.15
                                   0.000528
                                     <1
All Infants (< 1 year old)
                                       
                                   0.001637
                                       1
Children 1-2 years old
                                       
                                   0.002634
                                       2
Children 3-5 years old
                                       
                                   0.001724
                                       1
Children 6-12 years old
                                       
                                   0.000791
                                     <1
Youth 13-19 years old
                                       
                                   0.000417
                                     <1
Adults 20-49 years old
                                       
                                   0.000304
                                     <1
Adults 50+ years old
                                       
                                   0.000311
                                     <1
Females 13-49 years old
                                       
                                   0.000333
                                     <1

6.0 	RESIDENTIAL EXPOSURE AND RISK

      A new residential assessment is not required for the proposed new use on potato commodities because there are no residential uses associated with the proposed new use. 
 
 7.0 	AGGREGATE EXPOSURE AND RISK ASSESSMENT 
 
	In accordance with the FQPA, when there are potential residential exposures to a pesticide, aggregate risk assessment must consider exposures from three major routes: oral, dermal, and inhalation.  There are three sources for these types of exposures:  food, drinking water, and residential uses.  In an aggregate assessment, exposures from relevant sources are added together and compared to quantitative estimates of hazard (e.g., a NOAEL or PAD), or the risks themselves can be aggregated.  When aggregating exposures and risks from various sources, HED considers both the route and duration of exposure.  There is potential for short-term residential exposure to NAA from ornamental uses.  Oral, dermal and inhalation exposures cannot be combined for short-term assessment, however, because oral exposure endpoints are not based on common toxicological effects with either dermal or inhalation endpoints.  Therefore, the acute and chronic exposure estimates provided in the dietary and drinking water exposure section represent aggregate exposure.  

8.0	CUMULATIVE RISK

      Section 408(b)(2)(D)(v) of FFDCA requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider "available information" concerning the cumulative effects of a particular pesticide's residues and "other substances that have a common mechanism of toxicity."

	EPA does not have, at this time, available data to determine whether NAA has a common mechanism of toxicity with other substances.  Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as to NAA and any other substances and, NAA does not appear to produce a toxic metabolite produced by other substances which have tolerances in the U. S.  For the purposes of this tolerance reassessment action, therefore, EPA has not assumed that NAA has a common mechanism of toxicity with other substances.  For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements released by EPA's OPP concerning common mechanism determinations and procedures for cumulating effects from substances found to have a common mechanism on EPA's website at http://www.epa.gov/fedrgstr/EPA_PEST/2002/January/Day_16/.

9.0	OCCUPATIONAL EXPOSURE/RISK CHARACTERIZATION

9.1 	Exposure Scenarios

	Occupational handler exposure to NAA K salt is expected for potato handlers involved in commercial and on-farm potato seed piece treatment (not for direct use in a hopper-box, planter-box, or slurry-box). Only short term exposures from inhalation and dermal exposure routes were assessed for all exposure scenarios.  Longer term MOEs were not calculated since exposure for more than 30 days is unlikely to occur based on use patterns. Occupational and exposure and risk estimates were conducted using maximum application rates and surrogate exposure data from the Pesticide Handlers Exposure Database and the Residential Exposure Assessment SOPs.  Dermal and inhalation exposures to workers should be aggregated for naphthalene acetic acid ethyl ester because dermal and inhalation endpoints are based on decreased body weight gain.  Exposure from post-application activities is unlikely.

 9.2	Handler Exposure 

      Occupational exposures from treating and planting treated potato seed pieces were assessed for this use. 
      
9.2.1 	Handler Exposure Scenarios

		9.2.1.1 Seed Treatment
      
      The occupational pesticide "handlers" for seed piece treatment are the individual who prepares the stock spray solution that is used in enclosed treatment systems (primary handlers) and the individuals who plant the treated seed (secondary handlers).  The primary handler activities are essentially the same as those performed by a mixer/loader supporting conventional ground or aerial spray operations.  HED assessed seed piece treatment conducted at large scale seed treatment facilities and also on-farm treatment using equipment similar to large commercial facilities.  Potato seed piece operations on and off- farm are large enough to facilitate farm scale planting and utilize equipment that is similar in principle and in treatment capability. 

      For assessing commercial seed treatment, unit exposure data were taken from a study titled "Determination of Dermal and Inhalation Exposure of Workers During On-Farm Seed Piece Treatment of Potatoes" submitted by Bayer CropScience (MRID 470547-02, DP Barcode: D378750, Seyed Tadayon, June 23, 2010).  The objective of this study was to determine the dermal and inhalation exposure of experienced agricultural workers performing on-farm liquid seed piece treatment to potatoes and the inhalation exposure of agricultural workers who were sorting and cutting the potato seed pieces near the treatment site.  The potato seed pieces were treated with imidacloprid, formulated as ADMIRE 240F, containing 21.4% of the active ingredient.  The study was conducted at eleven potato treating cooperator locations in the southern potato growing region of Manitoba, Canada and encompasses a range of personal protective equipment, treatment equipment, and other variables. The overall mean for total dermal exposure was 127.3 ug/lb ai or 0.1273 mg/lb ai handled.  The overall mean for inhalation exposure was 6.4 ug/lb ai or 0.0064 mg/lb ai handled.  
      
      Chemical-specific data for assessing exposure during commercial seed planting were not submitted to the Agency in support of this Section 18 application. Unit exposures are from ExpoSAC Policy 14: SOPs for Seed Treatment (May 1, 2003).  Unit exposure values from ExpoSAC Policy 14 are based on data for open mixing/loading/application systems. Potential occupational exposure scenarios from the use of NAA as a potato seed piece treatment include the following.
      
      
Treating Seed Pieces (Primary Handler)

      * Mixing, loading, applying liquid formulations;

Planting Treated Seed Pieces (Secondary Handler)

      Potential occupational exposure scenarios from the use of NAA as a potato seed piece treatment include planting treated seed (secondary handler).  Planting treated seed consists of the farmer purchasing bags of treated seed, placing the seed in the hopper and applying seed to fields (considered a secondary handler exposure scenario).  
      
      The overall mean for total dermal exposure was 127.3 ug/lb ai or 0.1273 mg/lb ai handled.  The overall mean for inhalation exposure was 6.4 ug/lb ai or 0.0064 mg/lb ai handled.  

9.2.2 	Handler Exposure Data
     
	No chemical-specific handler exposure data were submitted in support of this registration. It is HED's policy to use data from the USEPA OPP Occupational Pesticide Handler Unit Exposure Surrogate Reference Table (5/4/11). http://www.epa.gov/pesticides/science/handler-exposure-data.html). 

9.2.3 	Handler Exposure Assumptions  

		::	Average body weight of an adult handler is 80 kg.
	::	Exposure duration short-term (1- 30 days)
		::	Maximum label application rates for seed treatment is 0.00000028 lb ai/lb seed:
	::	Amount (pounds) of Seed Treated per Day (Primary Handler) 480,000
	::	Amount (pounds) of Seed Planted per Day (Secondary Handler) 480,000

9.2.4 	Handler Exposure and Risk Estimates

	9.2.4.1 Primary Handler Exposure and Risk Estimates

      The risk from mixing/loading liquid for potato seed piece treatment resulted in a combined (dermal + inhalation) MOE greater than the level of concern (i.e., LOC =100) and not of concern to HED.  Table x summarizes the calculations for potato seed piece treatment handler exposures and risks.

Table 8. Short-Term Occupational Handler Exposure and Risk for Mixing/Loading for Potato Seed Piece Treatment
                              Application Rate[a]
                                (lb ai/lb seed)
                           Amount Treated Per Day[c]
                                   (lb seed)
                               Unit Exposures[b]
                              Dosed  (mg/kg/day)
                                MOEs LOC = 100
                                       
                                       
                                Baseline Dermal
                                  (mg/lb ai)
                              Baseline Inhalation
                                  (mg/lb ai)
                              Absorbed Dermal[e]
                                 Inhalation[f]
                                   Dermal[g]
                                 Inhalation[h]
                        Baseline Dermal + Inhalation[i]
                                 Mixer/Loader
                                  0.00000025
                                    480,000
                                    0.1273
                                    0.0064
                                    0.00021
                                   0.000011
                                   1,400,000
                                   4,700,000
                                   1,100,000
a	Application Rates based on proposed uses on label for Rejuvenate Seed Treatment.
b	Unit Exposures based on study (MRID 470547-02, DP Barcode: D378750) mean exposure (mg/lb ai).
c	Amount Treated Per Day was based on National Potato Council Data.
d	Baseline Dermal:  Long-sleeved shirt, long pants, and no gloves; Baseline Inhalation: no respirator.  
e	Absorbed Dermal Dose (mg/kg/day) = daily unit exposure (mg/ - lb ai) x application rate (lb ai/lb seed) x amount treated/day (lb seed/day)  x dermal absorption factor (100%) / -  body weight (70 kg adult).
f	Inhalation Dose (mg/kg/day) = daily unit exposure (μg/lb ai) x application rate (lb ai/lb seed) x amount treated /day (lb seed/day) x inhalation absorption factor (100%) / body weight (80 kg adult).
g	Dermal MOE = short-term NOAEL (300 mg/kg/day) / absorbed dermal daily dose (mg/ - kg/ - day).  Level of concern = 100.
h	Inhalation MOE = short-term NOAEL (50 mg/kg/day) / inhalation daily dose (mg/kg/day). Level of concern = 100.
i	Total MOE = 1 / [(1 / Dermal MOE) + (1 / Inhalation MOE)]. Level of concern = 100.
 
      9.2.4.2	Secondary Handler (Planter) Exposure and Risk Estimates
      
      Table x shows that the planter (secondary handler) combined (dermal + inhalation) short-term exposure risks do not exceed HED's level of concern (i.e., LOC is an MOE = 100) for handlers planting potato-treated seed pieces.

Table 9. Summary of Secondary Handler (Planter) Exposures and Risks for NAA K Salt LOC = 100
                                   Seed Type
                                 Dermal UE[a]
                                    (mg/lb)
                                  Inhal UE[a]
                                    (mg/lb)
                                Max App Rate[b]
                                (lb ai/lb seed)
                          Amt of Seed Planted/Day[c]
                                 (lb seed/day)
                                Dermal Dose[d]
                                  (mg/kg/day)
                                 Dermal MOE[f]
                                   LOC = 100
                              Inhalation Dose[e]
                                   (mg/kg/d)
                               Inhalation MOE[g]
                                       
                                 Total MOE[h]
                                       
                                 Potato Pieces
                                     0.25
                                    0.0034
                                  0.00000028
                                    480,000
                                    0.00043
                                    720,000
                                   0.0000056
                                   8,900,000
                                    670,000
a	Unit Exposures from HED Exposure Science Advisory Council Policy 14: Standard Operating Procedures for Seed Treatment.  
b	Application Rates based on proposed label uses for NAA K salt.
c	HED default for lb seed planted per day from on National Potato Council.
d	Daily Dermal Dose (mg/kg/day) = daily dermal unit exposure (mg/ - lb ai) x application rate (lb ai/lb seed) x amount planted (lb seed/day) x absorption factor (100%) / -  body weight (70 kg adult).
e	Dermal MOE = NOAEL (300 mg/kg/day for short- and intermediate-term exposure) / Dermal Dose (mg/kg/day). Level of concern = 100.
f	Daily Inhalation Dose (mg/kg/day) = daily inhalation unit exposure (mg/ - lb ai) x application rate (lb ai/lb seed) x amount planted (lb seed/day) x absorption factor (100%) / -  body weight (80 kg adult).
g	Inhalation MOE = NOAEL (50 mg/kg/day for short- and intermediate-term exposure) / Inhalation Dose (mg/kg/day). Level of concern = 100.
h	Total MOE = 1 / [(1 / Dermal MOE) + (1 / Inhalation MOE)]. Level of concern = 100.

9.3	Post-Application Exposure 

      A quantitative post-application assessment for exposure to treated seeds that have already been planted was not conducted as exposure to these activities is considered unlikely.

 	9.3.1	Dermal Post-Application Exposure/Risks

      The potential for post-application exposures following the planting of NAA K salt-treated potato seed pieces is unlikely because sustained levels of contact with the treated seed piece after it has been placed in the soil or other planting media would not be expected because no routine cultural practice required for the production of agricultural commodities involves such an activity as defined in the no/low contact criteria in the Worker Protection Standard (WPS).  

 	9.3.2	Inhalation Post-Application Exposure/Risks

      A post-application inhalation exposure assessment is not required as exposure is expected to be negligible.  Seed treatment assessments provide quantitative inhalation exposure assessments for seed treaters and secondary handlers (i.e. planters).  It is expected that these exposure estimates would be protective of most post-application inhalation exposure scenarios.

10.0	REFERENCES

NAA HED Risk Assessment for Reregistration Eligibility, B. Daiss (D293881, 3/30/04)

NAA.  Amendment to Petition for New Use on Potatoes and an Exemption from the Requirement of a Tolerance for Residues of 1-Naphthaleneacetic Acid, Potassium Salt in/on Potatoes - PP#0F7687.  Residue Chemistry Considerations., S. Hummel, (D396076, date...) 

Napthaleneacetic Acid (NAA) Potassium Salt.  Occupational and Residential Exposure Assessment for a Section 3 use as a potato seed piece treatment, I. Nieves, (D396943, date)

Naphthalene Acetates- Acute and Chronic Dietary and Drinking Water Exposure and Risk Assessment for Section 3 New Use of Naphthalene Acetic Acid-ester on Potatoes, B.Daiss (D397389, date)

Tier I Estimated Drinking Water Assessment for the Propose New Uses of Potassium Naphthalene Acetate on Potato Seed and/or Potato Foliage for the New Products Renew PGR and Renew Concentrate PGR, J.L. Melendez (D387171, 5/20/11) 

Toxicology Chapter, A. Khasawinah (D293237 TXR No. 0052407, 3/8/04)
APPENDICES

   A. TOXICOLOGY DATA SUMMARY

A.1 		Guideline Data Requirements

                                 Guideline No.
                                                 Study Type
                                   Technical
                                   MRID No.


                                   Required
                                   Submitted
                                       
                  870.3100
                  
                  
                  
                  870.3150
                  
                  
                  
                  870.3200
                  
                  
                  870.3250
                  870.3465
                  Subchronic (Oral) Toxicity - Rodent	
                  
                  
                  
                  Subchronic (Oral) Toxicity - Non-Rodent	
                  
                  
                  
                  21/28-Day Dermal Toxicity	
                  
                  
                  90-Day Dermal Toxicity		
                  90-Day Inhalation Toxicity 	
                                       Y
                                       
                                       
                                       
                                       Y
                                       
                                       
                                       
                                       N
                                       
                                       
                                       N
                                       N
                                       Y
                                       
                                       
                                       
                                       Y
                                       
                                       
                                       
                                       Y
                                       
                                       
                                       N
                                       N
                                   43896001 
                                   00043624
                                   42932601
                                   43896002
                                   43895901
                                   00136446
                                   42983801
                                   43914901
                                   43581001
                                   43134701
                                   43581002
                                       
870.3700a
870.3700b

870.3800
                  Prenatal Developmental Toxicity - Rodent	
                  Prenatal Developmental Toxicity - Non-Rodent	
                  
                  Reproduction and Fertility Effects	
                                       Y
                                       Y
                                       
                                       Y
                                       Y
                                       Y
                                       
                                       Y
                                   00042765
                                   00137821
                                   00137822
                                   43796301
870.4100a
870.4100b
870.4200a
870.4200b
870.4300
                  Chronic (Oral) Toxicity - Rodent	
                  Chronic (Oral) Toxicity - Non-Rodent (Dog)	
                  Carcinogenicity - Rat..................		
                  Carcinogenicity - Mouse	
                  Combined Chronic Toxicity /Carcinogenicity
                                       Y
                                       Y
                                       Y
                                       Y
                                       Y
                                       Y
                                       Y
                                       Y
                                       Y
                                       Y
                                   44157501
                                   43744201
                                   44157501
                                   Lit Study
                                   44157501
870.6100a
870.6100b
870.6200a
870.6200b
870.6300
870.7800
                  Neurotoxicity - Acute Delayed Neurotox.- Hen	
                  Neurotoxicity  - Subchronic - Hen	
                  Neurotoxicity - Acute - Rat	
                  Neurotoxicity -Subchronic - Rat	
                  Developmental Neurotoxicity..................
                  Immunotoxicity.............................	
                                       N
                                       N
                                       Y
                                       Y
                                       N
                                       Y
                                       N
                                       N
                                       N
                                       N
                                       N
                                       N
                                      ---
                                      ---
                                       
                                       




















A.2 Toxicity Profiles

Study

pc 056001: acetamide

pc 056002: NAA

pc 056007: Na salt

pc 056008: ethyl ester

Acute - oral

MRID 43495901
LD50 > 5050 mg/kg
Category III

MRID 00103128
LD50 (95% C.I.) = 2520 mg/kg (2100-3021) .

MRID 00108829
LD50: Males 1.35 (1.12 - 1.64)
Females 0.933 g/kg (0.631-1.38 )

MRID 43494101
LD50 2186 (1907-2506)  mg/kg
Category III

Acute - Dermal

MRID 43495902
LD50 > 2020 mg/kg
Category III

MRID 00103129 
LD50 is greater than 2 g/kg. Category III. 

MRID 00108829
dermal LD50 = > 2 g/kg.  Category III

MRID 43494102
LD50 > 2020 mg/kg.  Category III

Acute - Inhal.

MRID 43495903
LC50 > 2.17 mg/L
Category IV





MRID 43494103
LC50 > 2.13 mg/L
Category IV

Eye Irritation

MRID 00103051
corrosive Category I
MRID 43495904
minimally irritating
Category IV

MRID 00103127
corrosive Category I

MRID 00108829
corrosive Category I

MRID 43494104
minimally irritating
Category IV

Derm.  Irritation



MRID 00103127
Non-irritating  Category IV

MRID 00108829
Non-irritating  Category IV

MRID 00103053 & 00103218. 
non-irritating  Category IV

Sensitization

MRID 43495905
not a skin sensitizer.  No positive control.  Unacceptable

MRID 00153217
not a skin sensitizer



MRID 43494105
not a skin sensitizer.  No positive control.  Unacceptable

90-day -  rat

MRID 43896001
 0, 250, 1,000, or 4,000 ppm ( 0, 19.1, 73.8, or 292.1 mg/kg/day for males and 0, 20.4, 81.5, or 313.5 mg/kg/day for females). LOAEL is 4,000 ppm (292.1 mg/kg/day) decreased bw , bw gain & food consumption, and increased relative liver weights with adaptive histopathological changes in both sexes.  NOAEL is 1,000 ppm (73.8 mg/kg/day)

MRID 00043624
0, 50, 150, or 300 mg/kg/day to SD rats (20/sex/dose)
LOAEL for toxic effects is 300 mg/kg/day based on decreased body weight in both sexes and enlarged liver weights in females.  The NOAEL is 150 mg/kg/day.

MRID 42932601
0, 200, 2000, or 8000 ppm (13.9, 136.6, and 564.9 for males and 15.2, 149.3, and 583.4 mg/kg/day for females).  LOAEL for systemic toxicity = 2000 ppm (136.6 for males and 149.3 mg/kg/day for females) with a NOAEL for systemic toxicity of 200 ppm (13.9 for males and 15.2 mg/kg/day for females) based on decreased hematocrit and hemoglobin, increased liver weights and vacuolation of the periportal hepatocytes along with hypertrophy of the cells of the adrenal cortex zona glomerulosa.

MRID 43896002
 0, 400, 2000 or 8000 ppm (Average doses at  study end were 19-25; 92-123 ; and 388 - 519 mg/kg/day for males- females).  LOAEL= 8000 ppm (594 mg/kg/day), based on lower bw, bw  gain, and food consumption.  males and females at this dose also exhibited increased total bilirubin (19-21% higher) in conjunction with reduced RBC counts, hemoglobin, and hematocrits.  NOAEL= is 2000 ppm (144mg/kg/day).

10-day range finding - rat



MRID 00043623
0, 250, 1000 or 4000 mg/kg bw/day by gavage for 10 days (3 rats/sex/dose).  Death of all high dose rats, one female in the mid dose and none in the low dose.   Dose related depression in body weight gain and food consumption. Discoloration of lungs, liver and kidneys, distended bladder (high dose), blood and gas in the GI tract.  The MTD would be 250 mg/kg/day.





90-day - dog

 MRID 43895901
 0, 30, 100, or 300 mg/kg/day for 13 weeks.  LOAEL is 300 mg/kg/day, based on increased platelet count, decreased red cell parameters, and increased mean corpuscular volume which correlate with histopathological changes observed in the liver, spleen, and bone marrow in both sexes.  The NOAEL is 100 mg/kg/day.

MRID 00136446
0, 50, 150, or 300 mg/kg/day for 6 months to beagle dogs (4/sex/dose) by gelatin capsules. 
The LOAEL was 50 mg/kg/day, the lowest dose tested, based on hepatic liver changes (pericholangistis).  No NOAEL derived from this study.  

MRID 42983801
 0, 25, 150, or 450 mg/kg/day. LOAEL for systemic toxicity =150 mg/kg/day based on lesions of the GI tract and hypocellularity of the bone marrow. NOAEL for systemic toxicity is 25 mg/kg/day .

MRID 43914901
 0, 40, 125, or 400 mg/kg/day for 13 weeks.  LOAEL= 400 mg/kg/day, based on soft/liquid feces and depressed body weight gains of male and female dogs.  Blood parameters (RBC, hemoglobin, hematocrit and mean platelet volume) were all depressed in the male dogs at this level.   NOAEL = 125 mg/kg/day.

21-day - dermal

MRID 43581001
 0, 100, 300, or 1000 mg/kg for 6-6.5 hours/day, 5 days/week, for 3 weeks.  No LOAEL was established.  The NOAEL was the highest treatment level, 1000 mg/kg body weight.



MRID 43134701
0, 100, 300, or 1000 mg/kg for 6-6.5 hours/day, 5 days/week, for 3 weeks.  LOAEL for systemic toxicity is 1000 and NOAEL = 300 mg/kg/day based on reduced bw gain and food efficiency.   LOAEL for dermal toxicity = 1000 mg/kg Dermal Toxicity NOAEL = 300 mg/kg based on microscopic changes in the skin.

MRID 43581002
 0, 100, 300, or 1000 mg/kg for 6-6.5 hours/day, 5 days/week, for 3 weeks.  LOAEL for systemic toxicity is >1000 mg/kg/day and NOAEL =1000 mg/kg/day.  LOAEL for dermal irritation = 100 mg/kg, based on the presence of treatment-related dermal irritation in the treated ski.  No NOAEL for dermal irritation was established.

28-day inhal.

Not available

Develop.- rat



MRID 00042765
0, 10, 50 or 250 mg/kg/day gastric intubation to pregnant rats (24/group).  Developmental LOAEL is >250 mg/k/day and the NOAEL is 250 mg/kg/day.   Maternal toxicity LOAEL 250 mg/kg/day based on decreased body weight gain during the compound administration and the NOAEL is 50 mg/kg/day.

MRID 46685803
0, 15, 50 or 150 mg/kg bw/day from days 5 through 21 (inclusive) of gestation.
maternal LOAEL is >150 mg/kg bw/day, and the maternal NOAEL is 150 mg/kg bw/day
Developmental LOAEL is 150 mg/kg/day based on decreased fetal weight and minor skeletal changes (centrum 5 not ossified, cervical arch 7 cartilage fused to arch 6 cartilage, shortened 7[th] cervical rib),
compound administration and the NOAEL is 50 mg/kg/day.



Develop. - Rabbit



MRID 00137821, 00137822
doses 0, 37.5, 75 or 150 mg/kg/day
maternal toxicity NOAEL = 75 mg/kg/day based on lethality at the LOAEL of 150 mg/kg/day. The teratogenic and fetotoxic LOAEL = >150 mg/kg/day and NOAEL = 150 mg/kg/day.

MRID 46685801
dose levels of 0, 30, 100 or 300 mg/kg bw/day from days 5 through 29 (inclusive) of gestation
maternal LOAEL is 300 mg/kg/day based on reduced body weight, body weight gain and reduced food consumption, clinical signs (few/no feces) and stomach irritation (red/black spots/areas in the glandular mucosa of the stomach) and NOAEL = 100 mg/kg/day .
Developmental LOAEL is 300 mg/kg/day based on an increase in the overall incidences of fetuses with minor skeletal defects and variants (dumbell ossification of the 7[th] thoracic centrum, extra thoracolumbar ribs and 27 pre-pelvic vertebrae) and a decrease in ossification of the manus and NOAEL = 100 mg/kg/day.



Reproduction





MRID 43796301
0, 100, 1000 or 3000 ppm [0, 7, 69 or 210 and 0, 8, 81 or 239 mg/kg/day for males and  females].  Systemic and repro./develop. LOAEL = 3000 ppm (210 & 239 mg/kg/day for males & females), based upon reduced bw gain and food consum. in parental animals and reduced litter survival, and pup weight throughout lactation in both generations of offspring. Systemic and repro./develop. NOAEL = 1000 ppm (69 & 81 mg/kg/day for males & females)



Chronic/Onco - rat





MRID 44157501
 0, 100, 1000, or 5000 ppm (0, 4.4, 43.8, and 224.5 mg/kg/day for males and 0, 5.6, 55.8, and 303.6 mg/kg/day for females). LOAEL = 5000 ppm (224.5 mg/kg/day for males and 303.6 mg/kg/day for females), based on an increased incidence of stomach (mucosal gland dilation) and lung lesions (focal alveolar macrophages) in both sexes, and on lowered  bw gain and food efficiency in females.   NOAEL= 1000 ppm (43.8 mg/kg/day for males and 55.8 mg/kg/day for females).  Increased incidence (p  0.01) of uterine endometrial stromal polyps in high-dose females (2/60, 1/60, 3/60, 13/60 at 0, 100, 1000, 5000 ppm, respectively).



Chronic - mouse

NCI study .  (Innes et al 1969).   NAA acetamide was tested at one dose (MTD according to the published article) as part of a testing program of 120 chemicals.  Only the preliminary results were published.  The test materials were administered to two hybrid strains of mice : C57BL/6 x C3H/Anf and C57BL/6 x AKR (18/sex/hybrid strain).  The mice were administered NAA acetamide at one week of age by stomach intubation at 464 mg/kg/day until weaning at 4 weeks of age and administered the NAA acetamide in the diet at 1298 ppm for approx. 18 months.  Gross and hostopath. examination of the mice at the end of the feeding period did not reveal a significant increase in tumors over the controls.



MRID 46685802
0, 100, 500, or 2500 ppm [0, 10.8, 53.3, 276.0 / 0, 14.3, 70.9, 348.7 mg/kg bw/day M/F, respectively] for at least 80 weeks.
LOAEL = 2500 ppm [276 (M), 348.7 (F) mg/kg/day], based on ↓body weight, food consumption, ↑liver and kidney weights in both sexes and epididymis in males, ↓brain weights in males, hepato-cellular vacuolation in males, adenomas of the liver and lung in males, ↑in the incidence of multiple tumors in females. The NOAEL is 500 ppm [53.3 (M), 70.9 (F)] mg/kg/day. 
There was no treatment related increase in tumor incidence when compared to controls. Dosing was considered adequate based on the effects observed on the top dose (2500 ppm/kg/day).



Chronic - dog





MRID 43744201
 0, 15, 75, or 225 mg/kg/day. LOAEL=  75 mg/kg/day in males and 225 mg/kg/day in females, based on emesis, capsular regurgitation incidences, gross and histopathologic changes in stomachs, and sinusoidal histiocytosis in livers.  NOAEL= 15 mg/kg/day in males and 75 mg/kg/day in females.



Gene mutation-bacterial

MRID 43581006
 Salmonella  five doses 100-5000 ug/plate.  No mutagenic effect with or without S9 activation

MRID 00042761 
Escherichia coli polA.  Strains W3110 and p3478 at 1, 2 or mg/ml. Not mutagenic.  
MRID 00042762
Salmonella.  At 0.5-5000 ug/plate. Not mutagenic:



MRID 43581004
 five doses 33-5000 ug/plate.  No mutagenic effect with or without S9 activation

Gene mutation - mammalian: mouse lymphoma cells

MRID 43580202
-S9: not mutagenic.
+S9 mutagenic at 100 ug/mL and above 





MRID 43580201
-S9: not mutagenic.
+S9 mutagenic at 300 ug/mL and above

erythrocyte micronuleus mice

MRID 43581005
 ip injections 250, 500 or 1000 mg/kg to 5 mice/sex.  Lethargy and death at high dose.  Did not induce a clastogenic or aneurogenic effect.

MRID 00042763
ip injections 60 or 125 mg/kg to 4 mice/sex.  No overt aymptoms at high dose.  Negative.



MRID 43581003
 ip injections 305, 610, or 1220 mg/kg to 5 mice/sex.  Lethargy and death (48%) at high dose.  Did not induce a clastogenic or aneurogenic effect

Mitotic gene conversion: Saccharomyces cervisiae



MRID 00042758, 00042759, 00042760
NAA was tested at 10[-2], 10[-3], 10[-4], 10[-5], 10[-6] M.. NAA was not mutagenic in this test system.  Unacceptable.  No purity, not run at toxic dose, no S9 activation





Rodent dominant lethal assay



MRID 00042764
oral doses of  125, 250, or 500 mg/kg/day to 10 male rats/dose for 5 days.  NAA did not produce dominant lethal effects as measured by pre implantation and post implantation losses. 





Metabolism

Dixon et al.1977.  NAA [14]C as Na salt.  60-100% of the AD was excreted in the urine by the end of 48 hours.  The glucuronic acid conjugate (GAC): major urinary metabolite in man, rhesus monkey, marmoset, rabbit, rat, and fruit bat.  In th cat, no GAC was detected; but turine and glycine conjugates  The glycine conjugate was a major urinary metabolite (>20%) in the cat, squirrel and bushbaby monkey and a minor metabolite in rabbit, rat, capuchia and marmoset monkey.  1-NAA glutamine conjugate was formed only in the cynomolgus , squirrel and capuchin monkeys and marmoset in amounts not exceeding 3% of the AD.  1-NAA turine was excreted by all species except the rabbit, rat  and the fruit bat.  It was a major excretion product (>6%) in the squirrel and capuchin monkeys, the marmoset and the cat.  When female rats were given ip doses of 5-500 mg/kg, bile duct cannulation showed that 10-44% of the radioactivity was present in the bile 3 hours after injection., while 0.6-32% was present in the urine.  At the higher doses urinary GAC predominated whereas at the lower doses the glycine conjugates predominated.  In the bile the GAC was the major metabolite (>80% of the bile radioactivity) and the glycine conjugate was a minor metabolite (<4% of the bile radioactivity).  There was no analysis of the fecal radioactivity.

Lethco and Brouwer, 1966. carboxy -[14]C-1- NAA as NA salt in male rats.  Within 3 days, 71-90% of the AD was excreted in the urine.  At the lower doses (0.1-100 mg/kg)  most of the radioactivity was excreted during the first 24 hours, while at the higher dose (250 mg/kg), excretion was highest on the second day.  Fecal excretion was 3-10% at the 0.1-1.0 mg/kg doses and 14-21% of the AD at the 100 and 250 mg/kg doses.  After the third day, no radioactivity was detected in the feces or urine at any dose.   70-93% of the urinary radioactivity was NAA glycine conjugate and NAA GAC.  The GAC predominated at the two high doses and the glycine conjugate predominated at the lower dose.  Minor amounts of  NAA and two other minor unidentified metabolites were detected in the urine.   Bile cannulation experiments demonstrated biliary metabolism and excretion of the test material.  At the high dose a maximum of 29% of the AD was recovered at 6 hours, while a maximum of 54% was recovered at the low dose at 2 hours.  At the low dose, the NAA glycine conjugate was the major urinary metabolite and the NAA GAC was a minor metabolite, while in the bile the preponderance of these two metabolites was reversed.  Unchanged NAA was detected in the bile but not in the urine at both doses.  At the high dose the NAA GAC was the major metabolite in both urine and bile while the glycine conjugate was a minor metabolite.

MRID 43961701.  Rats (5/sex) were given a single 1 or 100 mg/kg bw oral dose of [[14]C] ring labeled -1-naphthaleneacetic acid, ethyl ester, or a 14-day repeated dose (1 mg/kg/day) of unlabeled material followed by a single dose of the labeled material.  Overall recovery of AD was 98.6-101.8%.  NAA ethyl ester was readily absorbed and excreted within 36 - 48 hours following all exposure regimens (urinary excretion: 67.6-85.3% of the AD at the low dose and 61.8-78% of the AD at the high dose).  Fecal excretion was 12.3-35.2% of the AD.  Tissue radioactivity was very low.  The major pathway of metabolism involved ester cleavage followed by glycine and glucuronide conjugation at the low and low repeat doses.  At the high dose, glucuronide conjugation appeared to play a more important role following ester cleavage.  Parent compound was detected at low concentrations (0.5-4.7% of administered) only in feces. 

MRID 43963301.  Rrats (5/sex) were given either a single 1 or 100 mg/kg bw oral dose, or a 14-day repeated dose (1 mg/kg/day) using [[14]C] ring labeled -1-naphthaleneacetamide (NAAD).  Overall recovery of the AD was 97.2-101%.  NAAD was readily absorbed and excreted within 36 hours (urinary excretion: 70.8-74.1% of the AD at the low dose, single or multiple,  66.2-69.5% of the AD excreted in urine at the high dose).  Fecal excretion was 21.6-26.2% of the AD.  Tissue radioactivity was very low (<0,5% of the AD).   Metabolism involved amide cleavage followed by glycine conjugation (13.7-47.3% of the AD) glucuronide conjugation (4.5-7.0% of the AD at the low dose and 12.8-18.1% of the AD at the high dose inthe urine).  For feces, the major metabolite detected was the dihydrodiol of naphthaleneacetamide (3.6-11.3% of the AD).  Parent compound was detected at low concentrations (0.7-1.9% of administered) only in feces. 



APPENDIX A.3	HAZARD IDENTIFICATION AND ENDPOINT SELECTION 

A.3.1	Acute Population Adjusted Doses (aPAD)  -  All Populations

Selected Study: Developmental Toxicity Study in Rats 
MRID 46685803

Dose and Endpoint for Establishing an aPAD: On the basis of this study, the dose selected is 50 mg/kg/day based on decreased body weight gain at 250 mg/kg/day during the gestation period.  This dose and endpoint is protective of the general population and is representative of the exposure duration of concern (effects occurred during administration of NAA during short period of exposure).  This was also the only available study on NAA with short exposure duration. 

Uncertainty Factor (UF): 100 This includes 10X for interspecies extrapolation and 10x for intraspecies variation.
      General Population aPAD =        (NOAEL) 25 mg/kg    =  0.25 mg/kg
                                                              (UF) 100	
      
      
      
      
A.3.2	Chronic Population Adjusted Dose (cPAD)  -  All Populations
       
Selected Study: Chronic/Oncogenicity Study in Dogs 
MRID 43744201
Dose and Endpoint for Establishing an cPAD: On the basis of this study, the dose selected is 15 mg/kg/day based on stomach lesions in 75% of the males consisting of necrosis of the fundic or pyloric epithelium and by slight sinusoidal histiocytosis in the liver of 50% of the males occurring  at 75 mg/kg/day of oral feeding of the NAA sodium salt.  The sodium salt also appeared to be the more toxic in subchronic testing among the NAA group of chemicals.  A chronic study in rats with NAA sodium salt showed a NOAEL of 44-56 mg/kg/day based on increased incidence of stomach (mucosal gland dilation) and lung lesions (focal alveolar macrophages) in both sexes, and on lowered body weight gain and food efficiency in female rats at 224 - 303 mg/kg/day.  Therefore, this dose and endpoint is appropriate for protecting the general population from dietary chronic exposure to NAA group of chemicals. 

Uncertainty Factor (UF): 100 This includes 10X for interspecies extrapolation and 10x for intraspecies variation.

   General Population  cPAD  =         (NOAEL) 15 mg/kg/day    = 0.15 mg/kg/day
		                                          (UF) 100
	   


A.3.4	Dermal Absorption


	A dermal absorption factor (DAF) is applied when dermal exposure endpoints are selected from oral toxicity studies.  The dermal factor converts the oral dose to an equivalent dermal dose for the risk assessment.  A DAF of 6% was selected for use in risk assessment based on available in vivo dermal absorption studies in rat and in vitro dermal absorption studies conducted with rat and human skin.  The DAF was selected by a special working group of the  Antimicrobials Division Toxicity Endpoint Selection Committee (12/18/08 memorandum from J. Chen to M. Swindell  -  Attachment A.3).

4.3.5	Dermal Exposure (Short and Intermediate-Term)

Selected Study: 21-day dermal toxicity study 
MRID 42090018

Dose and Endpoint for Establishing POD: In this study, the systemic NOAEL was 300 mg/kg/day based on reduced body weight gain and food efficiency at the LOAEL of 1000 mg/kg/day.  Therefore, the dermal dose for risk assessment is 300 mg/kg/day.  A margin of Exposure (MOE) of 100 is applied.

Uncertainty Factor (UF): An MOE 100 is required for the short- and intermediate-term scenarios for dermal exposure is based on the conventional uncertainty factor of 100.  This includes 10x for interspecies extrapolation and 10x for intraspecies variation..
      
A.3.6 	Inhalation Exposure (Short- and Term) 

Selected Study: Developmental Toxicity Study in Rats
See Section A.3.1

A.3.6  Inhalation Exposure (Intermediate Term)

Selected Study: 90 day oral toxicity study in dogs 
MRID 42983801

Dose and Endpoint for Establishing POD:  In this study, the systemic NOAEL was 25 mg/kg/day based on lesions of the GI tract and hypocellularity of the bone marrow at the LOAEL of 150 mg/kg day.  Therefore, the dose for risk assessment is 25 mg/kg/day.  

Uncertainty Factor (UF): An MOE 100 is required for the intermediate-term scenarios for dermal exposure is based on the conventional uncertainty factor of 100.  This includes 10x for interspecies extrapolation and 10x for intraspecies variation..













A.4		EXECUTIVE SUMMARIES FOR SUPPORTING TOXICITY STUDIES 

A.4.1	Subchronic Toxicity

870.3100: 	90-Day Oral Toxicity - Rat

In a subchronic oral toxicity study (MRID 00043624), 1-naphthaleneacetic acid, technical (Lot # not reported; purity not reported) was administered, in the diet, to Sprague Dawley rats (20/sex/dose) at dose levels of  0, 50, 150 or 300 mg/kg bw/day for 13 weeks.  Two additional group of 10 rats/sex were administered 0 or 300 mg/kg bw/day and sacrificed after 30 days and necropsied.  All rats survived except for one death in the control group.  No abnormal behavior or toxic effects were observed in the treated rats.  Fluctuations in food consumption occurred in control and treated groups.  Body weights in males and females of the high dose group were depressed particularly in the females where they gained only one third of the body weight achieved by the controls.  All hematologic values were within the reference limits.  Hematocrit, hemoglobin, and/or RBC values in the mid and high dose males and females were slightly reduced, but considered not compound related.  Alkaline phosphatase in the high dose group was elevated, probably associated with the rate of body growth.  Urinalysis values were comparable in all groups.  There were no visible macroscopic lesions in male rats except for one control male with enlarged spleen and liver and red, depressed areas in the stomach.  In the females, clear fluid in the uterus (hydrometra) was noted in 3 controls, 2 low dose, 7 mid dose and 5 high dose.  These and other lesions (ovarian cyst in one mid dose female, focal omental fat necrosis in one high dose female, one nenocortical cyst in another high dose female) observed were considered not be compound induced.  The absolute and relative liver weight in the high dose females appeared to be significantly increased with no histopathological findings. It was concluded that the LOAEL for toxic effects in this study is 300 mg/kg/day based on decreased body weight in both sexes and enlarged liver weights in females.  The NOAEL is 150 mg/kg/day.  This subchronic toxicity study in the rat was conducted prior to the current testing guidelines. 


In a subchronic toxicity study (MRID 43896001), 1-Naphthaleneacetamide (Lot # I940415; 98.7% a.i.) was administered to CRL:CD BR rats (10/sex/dose) by feeding at dose levels of 0, 250, 1,000, or 4,000 ppm (mean measured concentrations of 0, 19.1, 73.8, or 292.1 mg/kg/day for males and 0, 20.4, 81.5, or 313.5 mg/kg/day for females) for 90 days.  In the 4,000 ppm treatment groups, mean body weights were lower for males (10-15%) and females (9-12%) throughout the study, compared to controls.  Final mean body weight gains were lower for males (14%) and females (20%).  In addition, food consumption was consistently reduced for males (11-28%) and females (2-20%) throughout the study.  Mean relative liver weights were significantly increased in both 4,000 ppm males (14%; p0.05) and females (32%; p0.01) with accompanying histopathological changes consisting of enlarged (hypertrophied) centrilobular hepatocytes with an abundance of fine granular eosinophilic cytoplasm.  No rats died during the study.  No treatment-related differences in clinical appearance, ophthalmology, hematology, clinical blood chemistry or urinalysis parameter or gross pathology were observed in any treatment group.  No neoplastic tissue was observed in any of the treatment groups.  The LOAEL is 4,000 ppm (292.1 mg/kg/day), based on decreased body weight, reduced body weight gain, reduced food consumption, and increased relative liver weights with histopathological changes in both sexes.  The NOAEL is 1,000 ppm (73.8 mg/kg/day).

In a 90 day oral (diet) toxicity study (MRID 42932601), male and female Crl:CDBR (Sprague-Dawley) rats (10/group/sex) received 1-Napthaleneacetic Acid Sodium Salt (Lot # 214001; 96.44% purity) either 0, 200, 2000, or 8000 ppm (equivalent to 13.9, 136.6, and 564.9 mg/kg/day for males and 15.2, 149.3, and 583.4 mg/kg/day for females, respectively) for 13 weeks.  Dose levels were based on a 14-day dietary study with 1-Na-NAA, no information was provided.  No clinical toxicity or mortality related to the treatment was reported in any of the groups.  The absolute body weights for both sexes in the high dose groups were statistically significantly different from control from day 7 for males and day 14 for females, approximately 18 to 20 % lower than control for both sexes at the end of 90 days.  Systemic toxicity was noted at 2000 ppm and above based on statistically significant (p<0.05 -p<0.01) decreased hematocrit and hemoglobin, increased liver weights and vacuolation of the periportal hepatocytes along with hypertrophy of the cells of the adrenal cortex zona glomerulosa in females and increased kidney weights in males.  Further, at the 8000 ppm dose group there were decreased body weight gains (25-30% decrease), decreased food consumption and decreased food efficiency along with decreased red blood cell parameters, platelet counts, total serum protein and albumin.  The liver and kidney weights (absolute and relative to body weight) were increased in high dose males and females along with hepatocellular hypertrophy (4/10 in high dose males and females) and vacuolation of the periportal hepatocytes (10/10 in mid and high dose females) and hypertrophy of the cells of the adrenal cortex zona glomerulosa (6/10 in the mid dose females and 7/10 in the high dose females, and 3/10 in high dose males) and urinary bladder mucosa (9/10 in high dose males and 7/10 in high dose females).  The LOAEL for systemic toxicity is 2000 ppm (136.6 mg/kg/day for males and 149.3 mg/kg/day for females) with a NOAEL for systemic toxicity of 200 ppm (13.9 mg/kg/day for males and 15.2 mg/kg/day for females) based on decreased hematocrit and hemoglobin, increased liver weights and vacuolation of the periportal hepatocytes along with hypertrophy of the cells of the adrenal cortex zona glomerulosa. 


In a subchronic oral toxicity study (MRID 43896002), 1-naphthaleneacetic acid, ethyl ester (Lot # AM 315002; 100% ai) was administered, in the diet, to CRL:CD BR rats (10/sex/dose) at dose levels of 400, 2000 or 8000 ppm for 13 weeks. The actual average doses at the end of the study were 19-25 mg/kg/day for the 400 ppm group, 92-123 mg/kg/day for the 2000 ppm group, and 388 - 519 mg/kg/day for the 8000 ppm group, for males and females, respectively. Lower body weight, body weight gain, food consumption and food efficiency were observed for the 8000 ppm males and females compared to the controls.  Body weights for the males were 7-13% lower and for the females were 9-21% lower than the corresponding controls throughout the study.  Body weight gains were significantly reduced for both sexes at various weekly intervals throughout the study, and by the end of the study, were 18 and 38% lower for males and females, respectively, than the control gains.  Mean food consumption by the males and females was 5-11 and 15-22 lower, respectively, than the control values for most weekly intervals; decreased food efficiency for both sexes was observed at most weekly intervals.  Increased relative and/or absolute liver and kidney weights were observed for the 2000 and 8000 ppm treatment groups.  Relative liver weights were 21% higher for the 2000 ppm females and 20 and 58% higher for the 8000 ppm males and females, respectively, compared to the control weights.  Absolute liver weights were 13 and 24% higher for the 2000 and 8000 ppm females, respectively, compared to the controls.  Relative kidney weights were higher for both sexes from the 2000 ppm (11% higher) and 8000 ppm (17-23% higher) treatment groups.  Absolute kidney weight for the 2000 ppm males was 16% higher than the controls but was not increased for the 8000 ppm males.  No associated macroscopic or microscopic changes were observed in the livers and kidneys of rats from any treatment group.  Decreased red blood cell counts, hemoglobin, and hematocrits for both sexes from the 2000 and 8000 ppm groups were not considered clinically significant, but appeared to be treatment-related since they were dose-dependent.  The 8000 ppm males and females also exhibited increased total bilirubin (19-21% higher) in conjunction with reduced red blood cell counts, hemoglobin, and hematocrits.  No other treatment-related effects were observed during the study.  No rats died during the study.  No differences in clinical signs, ophthalmology, macroscopic or microscopic pathology were observed between any of the treatment and control groups.  Decreased urine protein in the 2000 and 8000 ppm males was not observed in the corresponding females.  The LOAEL for this study is 8000 ppm (594 mg/kg/day) for male and female rats, based on lower body weight, suppressed body weight gain, and reduced food consumption as compared to the controls.  Absolute and/or relative liver and kidney weights for both sexes were seen at this dose but were not accompanied by any macroscopic or microscopic changes, however, males and females at this dose also exhibited increased total bilirubin (19-21% higher) in conjunction with reduced red blood cell counts, hemoglobin, and hematocrits.  The NOAEL is 2000 ppm (144 mg/kg/day) for both sexes. 
 
870.3150:	90-Day Oral Toxicity - Dog


In a subchronic oral toxicity study (MRID 00136446), 1-naphthaleneacetic acid, technical (Lot # 16388; purity not reported) was fed (gelatin capsules) to beagle dogs (4/sex/dose) at dose levels of 0, 50, 150, or 300 mg/kg/day for 180 consecutive days.  Clinical signs of toxicity were evident in the high dose group.  These included anorexia lasting several days, tenderness in the mouth while dosing, icteric and pale mucous membranes, steady loss in weight, lethargy, an uncoordinated gait, dark urine, and dark stools.  Two of four males and all the females showed some or all of these effects at the end of the study.  One dog had a great amount of edema in the hind legs progressing over 3 days until its legs were swollen to approximately the coxo femoral joint.  This dog was sacrificed on day 126 of the study.  Urine collected from this dog prior to sacrifice showed large amounts of bilirubin, urobilinogen and a small amount of RBC and blood.  These effects are considered to treatment-related.  The mean body weight and body weight gain was significantly depressed in the high dose females (p<0.01) at 2, 3, 4,5 and 6 months in comparison to the control dogs.  The male dogs had also reduced body weight and body weight gain during the last two months of the study.  Hematological parameters were within reference limits for the four groups.  The hematology of the dog that was sacrificed showed slightly increased WBC count with a relative and absolute neutrophilia and lymphopenia which may be compound related.  The clinical chemistry analysis showed that alanine amino transferase (SGPT) were elevated at 4 months (slightly) and 6 months (2x the normal value) for the high dose females.  The clinical chemistry of the male dog that was sacrificed in moribund condition showed lower protein, cholesterol and glucose and greatly elevated levels of total bilirubin, direct bilirubin, alkaline phosphatase, aspartate amino transferase (SGOT) and SGPT.  Dose-related increases in relative weights of kidneys occurred in both males and females of the high dose group.  Dose-related weight increases in liver, adrenals, brain and heart occurred in high dose females.  The low dose group males had increased relative kidney weights and the mid dose group females had an increase in relative heart weights.  Histopathologisal examination revealed very slight evidence of pericholangistis in the low dose group (2/8), very slight to moderate degree of hepatic insult in the mid dose group (7/8)and slight to severe degree of hepatic insult in the high dose group (8/8).  This hepatic insult was characterized by pericholangistis, toxic degeneration of hepatocytes and hepatocellular hypertrophy in the mid dose group and additionally centrilobular necrosis, periportal fibrosis in the high dose group and hyperplastic nodule in the male dog that was sacrificed moribund.  There was also evidence of squamoid metaplasi in the tracheal epithelium of 2/8 dogs and a slight degree of myocarditis (1/8) in the high dose group.  Hyperkeratosis of the skin at the thoroacolumbar junction was seen in 2/8 dogs of the mid dose and 4/8 dogs of the high dose groups.  It was concluded that there was no NOAEL derived from this study.  The LOAEL was 50 mg/kg/day, the lowest dose tested, based on hepatic liver changes (pericholangistis).  This subchronic toxicity study in the dog was conducted prior to the current testing guidelines. 


In a subchronic toxicity study (MRID 43895901), 1-Naphthaleneacetamide (Lot/Batch #  I940415;  98.7% a.i.) was administered via capsule to four beagle dogs/sex/dose at dose levels of 0, 30, 100, or 300 mg/kg/day for 13 weeks.  In the 300 mg/kg/day treatment group, all livers contained accumulations of a hemosiderin-containing pigment in the reticuloendothelial cells and bilirubin in the intracanicular spaces.  The spleens of 3/4 males and 2/4 females also contained hemosiderin and hematopoiesis was increased in the bone marrow in 3/4 animals of both sexes.  Decreases in red blood cell counts, hematocrit, and hemoglobin occurred in both sexes.  Platelet counts and mean corpuscular volumes were increased in both sexes.  Total bilirubin was increased in 1/4 males and 3/4 females, but the increases were significant (p<0.05 or 0.01) only for females.  Body weights were reduced in males only.  Clinical signs of toxicity in both sexes were soft or liquid feces.  No treatment-related effects were observed in the 30 or 100 mg/kg/day treatment groups.  No dogs died during the study.  No treatment-related differences in clinical appearance, food consumption, ophthalmology, urinalysis parameters, organ weights, or gross pathology were observed in any treatment group.  No neoplastic tissue was observed in any of the treatment groups.  The LOAEL is 300 mg/kg/day, based on increased platelet count, decreased red cell parameters, and increased mean corpuscular volume which correlate with histopathological changes observed in the liver, spleen, and bone marrow in both sexes.


In a 13 week oral toxicity study (MRID 42983801), 6-month old beagle dogs (4/group/sex) received by capsule either 0, 25, 150, or 450 mg/kg/day 1-Naphthaleneacetic Acid Sodium Salt (Lot# 214001, Purity - 96.44% 1-NAA & 1.79% 2-NAA).  Due to inappetence at the high dose, the feeding regimen was altered for several high dose animals to reduce excessive weight loss.  Dose levels were based on a previous 6 month study with Naphthalene Acetic Acid (MRID 00136446) where male and female dogs receiving 50, 150, or 300 mg/kg/day experienced severe toxicity at the 300 mg/kg/day dose.  These included depressed body weight and body weight gain, histopathological changes and mortality.  In the current study with NAA sodium salt, none of the animals died.  Regurgitation of intact or partially digested capsules and emesis were the most common treatment- related clinical sign and was toxicologically significant at the high dose.  Body weight gain was significantly reduced in the high dose males (15% of controls, p<0.05) and females (29% of controls, p<0.05) accompanied by decreased food consumption and food efficiency.  There were statistically significant increases in relative organ weight for the liver, adrenals, thyroids/parathyroids, kidneys and brain and a decrease in gonad absolute and relative weights for the high dose males.  The high dose females only showed a statistically significant increase in relative kidney weights, although the relative weights for other organs did show a tendency towards an increase.   Gross examination of the genital tract revealed small prostates, small testes and epididymides in all high dose males.  Microscopic examination in these males revealed an increased incidence of hypospermatogenesis, characterized by less spermatogonia and spermatocytes and were associated with aspermia in the epididymides.  These may be secondary effects to the condition of the animals, but deserve further examination. Systemic toxicity was noted at 150 mg/kg/day and above based on  lesions of the gastrointestinal tract (ulcerative duodenitis and acute or erosive gastritis), hypocellularity of the bone marrow along with changes in liver enzymes (increased alkaline phosphatase in the high dose group), increased relative liver weights, histopathological changes of the liver (single cell necrosis, centrilobular necrosis, pigment accumulation, extramedullary hematopoiesis and mononuclear or mixed cell infiltration), depression in erythrocyte parameters (red blood cell count, hemoglobin and hematocrit levels in high dose females with a slight similar effect in males), decreased body weight gains, food consumption and food efficiency, inappetence and emesis in the high dose group.  The NOAEL for systemic toxicity is 25 mg/kg/day with a LOAEL for systemic toxicity of 150 mg/kg/day based on lesions of the gastrointestinal tract and hypocellularity of the bone marrow.

In a subchronic oral toxicity study (MRID 43914901), 1-naphthaleneacetic acid, ethyl ester (Lot/Batch # AM 315002; 97.75% ai) was fed (gelatin capsules) to beagle dogs (4/sex/dose) at dose levels of 0, 40, 125, or 400 mg/kg/day for 13 weeks.  All dogs survived the treatment.  Treatment-related clinical signs were limited to soft or liquid feces particularly in males and to a lesser extent in females at the high dose of 400 mg/kg/day.  Male dogs in the 40, 125, or 400 mg/kg/day treatment groups had a 4- to 5.5-fold increase in soft/liquid feces (maximum 65 instances during 13 weeks in the 400 mg/kg/day group) compared to the control group.  For females, there was one incident of soft/liquid feces in the control group, five in the 40 mg/kg/day group, eight in the 125 mg/kg/day group, and 19 in the 400 mg/kg/day group during the 13-week study.  A treatment-related lower body weight gain (20% less than the control) was seen in the males and females of the high dose group.  Males in the 40 or 125 mg/kg/day treatment group were 25-29% heavier, and males in the 400 mg/kg/day treatment group were 20% lighter than males in the control group; all three groups consumed 19% more food than the control during the study.   Female dogs in the 400 mg/kg/day treatment groups consumed 11% less food over the course of the study.  Male dogs in the 40, 125, or 400 mg/kg/day treatment groups had significantly (p <0.05 or 0.01) lower red blood cell, hemoglobin, and hematocrit levels, and lower mean platelet volumes (MPV) than the controls throughout the study.  In the high dose males at 12 weeks,  these were 18%, 17%, 17% and 22% lower than the controls for RBC, hemoglobin, hematocrit and MPV levels, respectively.  Although , these parameters were within the historical range values for this dog type, they were at the lower end of the range and may suggest anemic affects caused by the administration of this material at this dose.  Low white blood cell counts in female dogs in the 125 or 400 mg/kg/day treatment groups after 12 weeks of treatment were also within expected biological ranges.  No other treatment-related responses were observed during the study.  No differences were observed in clinical blood chemistry, ophthalmology, urine volume or chemistry, organ weights, or macroscopic or microscopic organ morphology between dogs in the treated and the control groups.  No neoplastic tissue was observed.  The LOAEL for this study is 400 mg/kg/day, based on soft/liquid feces and the depressed body weight gains of male and female dogs at this treatment level.  Additionally some blood parameters (RBC, hemoglobin, hematocrit and mean platelet volume) were all depressed in the male dogs at this level.  The NOAEL was 125 mg/kg/day. 

A.4.2	Prenatal Developmental Toxicity

870.3700a:	 Prenatal Developmental Toxicity Study - Rat

In a prenatal developmental study (MRID 00042765), NAA technical (Lot # NAA 73323G; purity not reported, white powder) was administered by gastric intubation to groups (24/group) of healthy timed pregnant albino CD rats at dose levels of 0, 10, 50 or 250 mg/kg/day in 0.05% sodium carboxymethylcellulose from days 6 through 15 of gestation.  The dams were observed daily for signs of toxicity and weighed on day 1, 3, 6-15, 17 and 20 of gestation.  On day 20 of gestation the dams were euthanized with ether and the ovaries and uterine contents were immediately examined for viable and nonviable fetuses, resorptions, number of implantations, and number of corpora lutea.  Fetuses were examined for visceral and skeletal anomalies using proper techniques.   No deaths or toxic symptoms were reported at any dose level.  There was a statistically significant decrease in the mean body weight gain in the 250 mg/kg/day rats with the onset of the compound administration.  The dams in the 10 and 50 mg/kg/day groups did not show significant decrease in body weight gain during compound administration but showed a decrease compared to the controls from days 17-20.  Litter size and fetal loss were not affected by the treatment.  A slight decrease (statistically insignificant) in mean litter size (9.3, 9.3, 8.8 and 7.9 in the control, low-, mid-, and high-dose groups, respectively) was considered unrelated to treatment.  There was a statistically increased (p<0.05) mean preimplantation loss in the mid- and high dose groups (38.1-42.6%) in comparison to the control animals (20.6%).  However the means were within the range of the individual values of the control animals and were considered not treatment related. The incidence of major malformations and minor anomalies were comparable in all groups.  It was concluded that NAA is not teratogenic in pregnant rats at 250 mg/kg/day, the highest dose tested.  Therefor the developmental LOAEL is >250 mg/k/day and the NOAEL is 250 mg/kg/day.  The maternal toxicity LOAEL 250 mg/kg/day based on decreased body weight gain during the compound administration and the NOAEL for maternal toxicity is 50 mg/kg/day.


In another  developmental toxicity study (MRID 46685803), 1-Naphthaleneacetic acid sodium salt (97.4% a.i., batch/lot # 014-S0401-001) was administered to 24 female SD (Wistar-derived) rats/dose by gavage at dose levels of 0, 15, 50 or 150 mg/kg bw/day from days 5 through 21 (inclusive) of gestation.  All animals survived the duration of the study and all were pregnant with live fetuses in utero at scheduled termination on day 22 of gestation.  There were no treatment-related clinical signs.  Cesarean section data did not reveal any differences among all groups including the controls.  Maternal body weights of the 150 mg/kg/day females adjusted for initial weight were statistically significantly (p<0.01) lower than the control group from day 6 through day 17.  For the 50 mg/kg/day females body weights were lower during the first 4 days following the test material administration. Females in the low dose groups were not affected. Body weight gains were lower following the first day of treatment and recovered completely on the second day (low-dose group) and third day of treatment for the mid-and high-dose groups.  Sporadic lower food consumption occurred in the mid- and high-dose groups. Although the lower body weights seen in the high and mid dose groups were statistically significant, these are considered not to be biologically significant or adverse since these changes were only 1-4% lower than the controls. Therefore, the maternal LOAEL is >150 mg/kg bw/day, and the maternal NOAEL is 150 mg/kg bw/day.

A treatment-related effect at the high dose resulted in reduced mean fetal weights of male and female fetuses.  The only notable visceral anomaly was increased slightly dilated ureters with statistical significance in the mid (p<0.05) and the high doses (p<0.01). There were no treatment-related external malformations or variations of the fetuses.  Minor treatment-related skeletal malformations were seen at the high dose of 150 mg/kg/day.  These included an increased number of unossified centrum 5, increased number of cervical arch 7 cartilage fused to arch 6 cartilage, increased interruptions of thoracic rib 10 costal cartilage, increased number of long length cervical rib.  A treatment-related increased incidence of fetuses but not litters with a shortened 7[th] cervical rib was observed in the 50 and 150 mg/kg/day groups. The incidence of both fetuses and litters with an ossified calcaneum was lower than in the control group and indicated a reduction in ossification, in the 150 mg/kg/day group.  Reduced ossification of the mania and pes was seen at the high dose.  A statistically significant higher mean score for the pes was reported for the 50 mg/kg/day group, but the difference from the control mean was minimal. The developmental LOAEL is 150 mg/kg bw/day, based on decreased fetal weight and minor skeletal changes (centrum 5 not ossified, cervical arch 7 cartilage fused to arch 6 cartilage, shortened 7[th] cervical rib).  The developmental NOAEL is 50 mg/kg bw/day.

870.3700b:	Prenatal Developmental Toxicity Study - Rabbit


In a prenatal developmental study (MRID 00137822), NAA (Lot # RTS2846AC; 98.55% purity)  was administered by oral gavage to groups (16/group) of artificially inseminated Dutch Belted rabbits  (4 (1/2) to 5 months old) at dose levels of 0, 37.5, 75, or 150 mg/kg/day from days 6 through 27 of gestation.  These doses were selected on the basis of a range finding study (MRID  00137821) where groups (5 rabbits/group) were dosed NAA once daily by gavage at dose levels of 0, 28, 80 or 240 mg/kg/day from days 6 through 27 of gestation.  Animals were observed twice daily for mortality and once daily for toxic signs during the dosing period.  Animals that died were necropsied. Body weights were taken on days 0, 6, 12, 18, 24 and 28.  Surviving animals were sacrificed on day 28 and the uterus and ovaries were examined for viable and nonviable fetuses, resorptions, number of implantations, and number of corpora lutea.  One animal in the range finding study dosed at 240 mg/kg/day aborted on GD 28 following signs of toxicity consisting of hair loss, decreased feces and significant weight loss.  In the main study, one low dose animal died on GD 25 and three high dose gravid animals died during the study on GD 20, 22 and 27.  Only two of the high dose animals showed signs of toxicity (hair loss on the forelimbs, clear or white nasal discharge with dried material around the nose, decreased defecation and dry red material, presumably died blood, beneath the cage) prior to death.  Necropsy observations of the dead animals showed foamy fluid or congested lining in the trachea, congested lungs, fluid in the thoracic and/or abdominal cavities., reddening and/or erosions on the stomach mucosa, mucoid material or fluid in the intestines and pale liver or pitted kidneys.  Weights of the pregnant animals varied over the gestation period with some indication of treatment related loss in the high dose.  No compound-related abnormalities were observed in the pregnant animals at necropsy.  No compound-related effect was observed on implantation or fetal viability.  However, in the range finding study, an increase in the mean preimplantaion loss (23.2% at the low dose to 42.1% at the high dose compared to 11.4% in the concurrent control) occurred at all doses in the treated animals and appeared to be treatment related.  However, this increased preimplantation loss was considered problematic by the EPA reviewer since historical control data on 343 animals showed a preimplantaion loss of 30.8%.  Examination of the fetuses derived from the main study did not reveal any teratogenic effects.  It was concluded that the maternal toxicity NOAEL is 75 mg/kg/day based on lethality at the LOAEL of 150 mg/kg/day. The teratogenic and fetotoxic NOAEL was 150 mg/kg/day based on lack of developmental and fetoxic effects at the highest dose of 150 mg/kg/day tested.


In another developmental toxicity study (MRID 46685801) 1-Naphthaleneacetic acid sodium salt (97.4% a.i., batch/lot # 014-S0401-001) was administered to 24 female New Zealand White rabbits/dose in water by gavage at dose levels of 0, 30, 100 or 300 mg/kg bw/day from days 5 through 29 (inclusive) of gestation.  All animals survived the duration of the study except for one rabbit at the high dose which died on GD 22 due to a dosing error and one control rabbit was sacrificed on GD 24 following accidentally biting the dosing catheter into its esophagus.  A treatment related reduction in body weight and body weight gain was noted following the initial oral administration of 1-NAA Na salt to pregnant rabbits at the high dose of 300 mg/kg/day.  This was accompanied by initial reduction in food consumption.  Final body weights were comparable in all treatment groups.  Several dams receiving this dose were observed with few/no feces during the study.  Post mortem examination revealed red/black spots/areas in the glandular mucosa of the stomach in several of these dams indicating local irritation by the test material.  No adverse effects were noted in the dams at the lower dose of 30 and 100 mg 1-NAA Na salt /kg/day.  Cesarean section data did not reveal any statistically significant differences among all groups including the controls.  The LOAEL for maternal toxicity is 300 mg/kg/day based on reduced body weight, body weight gain and reduced food consumption, clinical signs (few/no feces) and stomach irritation (red/black spots/areas in the glandular mucosa of the stomach).  The maternal toxicity NOAEL of 1-NAA Na in pregnant rabbits derived from this study is 100 mg/kg/day.  

Developmental Toxicity.   The oral administration of 1-NAA Na salt during gestation to rabbits resulted in decreased mean fetal weights (males and females) at the high dose of 300 mg/kg/day. Mean fetal weights at the low- and mid-dose were comparable to the control group.  There was no effect by l-NAA-Na salt administration on the overall incidence of major external/visceral, skeletal or Bouin's head defects or on the incidence of any specific major fetal abnormalities. The defects were considered to be spontaneous in origin. Fetuses with minor defects of the head following Bouin's fixation and sectioning, and fetuses with minor external/visceral defects were comparable in all groups including the control.  There was no indication that any of the specific effects were attributable to the test material. Fetuses with minor skeletal defects were statistically significantly higher in the 300 mg/kg/day.  However, only one specific defect (dumbbell shaped ossification of the 7[th] thoracic centrum) was statistically significantly higher (p<0.01) in the 300 mg/kg/day group in comparison with the control group.  No variants were detected in the heads of the fetuses following Bouin's fixation and serial sectioning and no external/visceral findings were detected in any fetus.  The overall proportion of fetuses with skeletal variants was statistically significantly higher in the 30, 100 and 300 mg/kg/day groups in comparison with the control group, but there was no specific increase in any specific variant and is not attributable to the test material administration.  The incidence of lengthened costal cartilage of the 10[th] thoracic rib was statistically significantly higher in all groups administered 1-NAA-Na in comparison with the control group, although there was no evidence of a dose-related trend. However, the incidences of fetuses with shortened or lengthened 13[th] thoracolumbar ribs (i.e. extra ribs) and with 27 bilateral pre-pelvic vertebrae were statistically significantly increased in the 300 mg/kg/day group in comparison with the control group and were considered to be attributable to 1-NAA-Na administration.  The LOAEL for developmental toxicity is 300 mg/kg/day based on an increase in the overall incidences of fetuses with minor skeletal defects and variants (dumbell ossification of the 7[th] thoracic centrum, extra thoracolumbar ribs and 27 pre-pelvic vertebrae) and a decrease in ossification of the manus.  The NOAEL is 100 mg/kg/day.

A.4.3	Reproductive Toxicity

	870.3800 Reproduction and Fertility Effects  -  Rat MRID 42090018

870.3800:	Reproduction and Fertility Effects - Rat


In a 2-generation reproduction study (MRID 43796301) 1-Na-NAA (Lot # 214001; 96.44% a.i.) was administered to 35 Crl:CD(R)BR, rats/sex/group in diet at dose levels of 0, 100, 1000 and 3000 ppm [0, 7, 69 and 210 mg/kg/day for males and 0, 8, 81 and 239 mg/kg/day for females, respectively].  The dose levels were selected on the basis of previous toxicity studies in rats.  At 3000 ppm (HDT), treatment-related decreases in body weight  gain and food consumption were observed in the P1 and P2 females during premating and gestation periods and decrease in body weight gain in P2 males during the premating period.  Reductions in P2 male and female premating body weight gain, although appearing systemic in nature, may have been secondary to developmental toxicity in these animals.  Reduced survival and growth were observed in both F1 and F2 offspring.  No adverse effects were noted at 1000 ppm.  Systemic and reproductive/developmental LOAEL = 3000 ppm (210 mg/kg/day for males, 239 mg/kg/day for females), based upon reduced body weight gain and food consumption in parental animals and reduced litter survival, and pup weight throughout lactation in both generations of offspring.  Systemic and reproductive/developmental NOAEL = 1000 ppm (69 mg/kg/day for males, 81 mg/kg/day for females).

A.4.4	Chronic Toxicity

870.4100a:	Chronic Toxicity  -  Rat


In a combined chronic toxicity/oncogenicity study (MRID 44157501), 1- Naphthaleneacetic acid sodium salt (1-Na-NAA) (96.44% 1-NAA; 1.79% 2-NAA w/w; Lot no. 214001) was administered to Crl:CD(R) BR rats (80/sex/dose) in the diet at concentrations of 0, 100, 1000, or 5000 ppm (corresponding to 0, 4.4, 43.8, and 224.5 mg/kg/day for males and 0, 5.6, 55.8, and 303.6 mg/kg/day for females).  An interim sacrifice was performed at 12 months on 20 rats/sex/dose;  terminal sacrifice (main study) was after 20.5-23 months due to the high mortality and poor health in the treated and control groups.  There were no treatment-related effects on survival or clinical observations.  High-dose females had lower mortality than the controls (p  0.05).  Weekly body weights of the high-dose males were significantly lower for days 14-119 and 238-259 ( 8.8%; p  0.05 or 0.01), but their overall weight gain was similar to that of the controls.  The low- and mid-dose females' weekly body weights and overall weight gains were within 7.4% and 14% of controls, respectively (p  0.05 or 0.01).  High-dose females, however, had lowered weekly body weights ( 35%; p  0.01), total weight gain (61% of controls), and overall food consumption and efficiency (15% and 36% lower than controls, respectively).  Serum triglyceride levels were about 50% lower than control levels at 6 and 12 months in high-dose males, and were 66-78% lower at 12 and 18 months in high-dose females (p  0.05 or 0.01).  The urine protein content of high-dose females was decreased from 12 months to terminal sacrifice to only 4.1-6.1% of control values (p  0.05 or 0.01).  These clinical chemistry changes had no histopathological correlates and their toxicological significance is unknown.  High-dose males and females had a significantly increased incidence and severity of stomach mucosal gland dilation (p  0.05).  The incidence of focal alveolar macrophages (in some cases accompanied by focal chronic inflammation) was increased in mid- and high-dose females, and was correlated at the high dose with an increased incidence of grossly observed lung nodules (p  0.05 or 0.01).  The incidence of focal alveolar macrophages was also slightly increased in high-dose males (p = 0.071).  The LOAEL is 5000 ppm (224.5 mg/kg/day for males and 303.6 mg/kg/day for females), based on an increased incidence of stomach (mucosal gland dilation) and lung lesions (focal alveolar macrophages) in both sexes of rats, and on lowered body weight gain and food efficiency in females.  The corresponding NOAEL is 1000 ppm (43.8 mg/kg/day for males and 55.8 mg/kg/day for females).  The only neoplastic finding (p  0.01) was an increased incidence of uterine endometrial stromal polyps in high-dose females (2/60, 1/60, 3/60, 13/60 at 0, 100, 1000, 5000 ppm, respectively).  The longer survival time of the high-dose females (about 88 days) did not account for the greater incidence of these benign neoplasms.  The rats were dosed adequately, judging by the toxicologic findings in both sexes of high-dose rats.

870.4100b:	Chronic Toxicity - Dog

In a chronic toxicity study (MRID 43744201), 1-napthaleneacetic acid, sodium salt (Lot # 214001; 96.44% ai) was administered (gelatin capsules) to beagle dogs (4/sex/dose) at dose levels of 0, 15, 75, or 225 mg/kg/day for 52 weeks.  At 225 mg/kg/day, Na-NAA administration resulted in gross pathological changes in the stomach of one male and one female and histopathological changes in the stomachs of four males and one female. The latter were characterized by mucosal atrophy (3) and congestion (1) in males and hemorrhaging in the female.  Slight sinusoidal histiocytosis was observed in the livers of four males and three females.  Both males and females exhibited a high incidence of emesis and capsule regurgitation at the 225 mg/kg/day dose level.  At 75 mg/kg only males exhibited dose-related toxic response to Na-NAA as characterized by stomach lesions in three animals consisting of necrosis of the fundic or pyloric epithelium and by slight sinusoidal histiocytosis in the liver of two males.  No other definitive treatment-related changes were noted in organ weights or gross pathological changes. All microscopic tissue abnormalities, other than those mentioned, occurred randomly and sporadically in all study groups.  No neoplastic tissue was observed in beagles in the treatment or control groups.  No dogs died during the study.  No treatment-related differences were observed between the clinical appearance, body weights, food consumption, biochemistry, hematology, urinalysis, or ophthalmology of the treated and control animals.  The LOAEL is 75 mg/kg/day in males and 225 mg/kg/day in females, based on emesis, capsular regurgitation incidences, gross and histopathologic changes in stomachs, and sinusoidal histiocytosis in livers. The NOAEL is 15 mg/kg/day in males and 75 mg/kg/day in females.
         
A.4.5	Carcinogenicity

870.4200a:	Carcinogenicity Study - Rat

This study is described above in the chronic studies section.  An increased incidence of uterine endometrial stromal polyps occurred in female rats at 303 mg/kg/day dietary feeding of Na NAA for two years.  According to HED consulting pathologist, Dr.  John Pletcher these are considered to be benign proliferative lesions of no carcinogenic concern (email to Dr.  William Burnam of HED on 04/04/2002).  Na NAA was not carcinogenic in the rat. 

870.4200b:	Carcinogenicity (feeding) - Mouse

There is an NCI study published in 1969 where NAA acetamide was tested at one dose (maximum tolerated dose: according to the published article) as part of a testing program of 120 compounds.  Only the preliminary results were published (Innes et al, Innes JR, Ulland BM, Valerio MG, Petrucelli L, Fishbein L, Hart ER, Pallotta AJ, Bates RR, Falk HL, Gart JJ, Klein M, Mitchell I, Peters J. 1969.  Bioassay of pesticides and industrial chemicals for tumorigenicity in mice: a preliminary note.  J.  Natl Cancer Inst.  42: 1101-1114).  The test materials were administered to two hybrid strains of mice : C57BL/6 x C3H/Anf and C57BL/6 x AKR (18/sex/hybrid strain).  The mice were administered NAA acetamide at one week of age by stomach intubation at 464 mg/kg/day until weaning at 4 weeks of age and administered the NAA acetamide in the diet at 1298 ppm (equivalent to 195 mg/kg/day at the conversion rate of 0.15 mg/kg for 1ppm) for approximately 18 months.  Gross and hostopathologic examination of the mice at the end of the feeding period did not reveal a significant increase in tumors over the controls.

In a carcinogenicity study (MRID # 46685802), Naphthaleneacetic Acid Sodium Salt (97.4%, batch/lot # 014-S0401-001) was administered to 50 C57BI/10JfCD-1 Alpk mice/sex/dose in the diet at dose levels of 0, 100, 500, or 2500 ppm [equivalent to 0, 10.8, 53.3, 276.0 / 0, 14.3, 70.9, 348.7 mg/kg bw/day M/F, respectively] for at least 80 weeks.  There were no statistically significant differences in survival or clinical signs between treated groups and controls in either sex. At the top dose (2500 ppm), bodyweights in males and females were statistically significantly lower than controls throughout the study with a maximum effect of 11% at week 77 in males, and 5% in females at week 41. Food consumption in males and females at this dose level was statistically significantly lower than controls at some time points throughout the study while food utilization in males was statistically significantly lower than controls in weeks 1-4 and overall in weeks 1-13. Total white blood cell, monocytes and large unstained cell counts were statistically significantly higher than controls in females at the top dose. This apparent elevation is due to higher counts in 2 individual animals and is considered to reflect animals with lymphomas in which there is also a leukaemic response. This effect was not compound-related. Also, at the top dose, liver and kidney weights in both sexes and epididymis in males were statistically higher than controls while brain weights in males were statistically lower.  Masses in the liver were identified in 3 male rats at the top dose, and in one female at 100 ppm. Pancreatic masses were also identified in 2 females at 2500 ppm and in 1 female at 500 ppm. A four-fold increase, compared to controls, in the incidence of hepato-cellular vacuolation in the liver was observed in males dosed at 2500 ppm. A slight increase in the presence of mononuclear cell infiltration in the liver was also observed in both males and females at this dose level. An increase in the incidence of intratubular microlithiasis and tubular basophilia within the kidney was observed in females and an increase in interstitial mononuclear cell infiltration in the kidney of males at 2500 ppm. There was an increase in the incidence of marked degeneration in the testes in males dosed with 2500 ppm of compound. Associated with this change, there was an increase in the incidence of decreased spermatozoa within the epididymis and dilated rete within the testis.  At 2500 ppm, adenomas of the liver were observed in one male rat, and adenomas of the lung were observed two males. Adenocarcinomas of the liver were observed in one control male and two males given 2500 ppm. None of these changes achieved statistical significance. There was a statistically significant increase in the incidence of histiocytic sarcoma in females at 2500 ppm but it was within historical control levels. There was a statistically significant increase (overall) in the incidence of multiple tumors in females given 2500 ppm. However there was no statistically significant increase in any individual tumor type, the incidence was low, and there was no dose-response relationship. Therefore this difference was considered not to be compound related.  The LOAEL is 2500 ppm [276 (M), 348.7 (F) mg/kg/day], based on lower body weight, food consumption, increased liver and kidney weights in both sexes and epididymis in males, lower brain weights in males, hepato-cellular vacuolation in males, adenomas of the liver and lung in males, increase in the incidence of multiple tumors in females. 
The NOAEL is 500 ppm [53.3 (M), 70.9 (F)] mg/kg/day.  At the doses tested, there was no treatment related increase in tumor incidence when compared to controls. Dosing was considered adequate based on the effects observed on the top dose (2500 ppm/kg/day).

A.4.6	Mutagenicity

        Gene Mutation

GLN 870.5100, 
MRID 43581006: NAA Acetamide
MRID 00042761: NAA
MRID 43581004: NAA Ethyl Ester

No mutagenic effect was noted with or without microsomal activation at concentrations up to the toxic range of 5000 micrograms/plate in the initial tests or in the confirmatory assay.


        Chromosomal Aberrations

GLN 870.5395
MRID 43581005 NAA Acetamide
MRID 00042763 NAA
MRID 43581003 NAA Ethyl Ester

In Vivo Mammalian Cytogenetics - Erythrocyte Micronucleus Assay in Mice.  There was no indication that NAA technical or the acetamide or the ethyl ester induced a clastogenic or aneugenic effect in either sex at any dose or sacrifice time. 



GLN 870.5300
MRID 43580202: NAA Acetamide
MRID 43580201: NAA Ethyl Ester

In Vitro mammalian cell gene mutation -  L5178Y TK+/- Mouse Lymphoma Mutagenesis Assay.  NAA acetamide was tested up to cytotoxic levels (1250 μg/mL -S9 and 150 μg/mL +S9).  NAA Ethyl ester was tested up to cytotoxic levels (100 μg/mL -S9 and 300 μg/mL +S9).  Both were non mutagenic without S9 activation system, but positive with S9 activation system at or above 100 ug/mL for the acetamide and 300 ug/mL for the ethyl ester.



GLN 870.5450
MRID 00042764 NAA


Rodent Dominant Lethal Assay.  NAA did not produce dominant lethal effects in mice at oral doses of 125, 250 or 500 mg/kg/day as measured by pre implantation and post implantation losses

A.4.7	Neurotoxicity

A neurotoxicity screening battery is required.  The registrant has committed to either develop new data or submit existing data to satisfy this requirement by early 2014. AMVAC is in the process of determining the value of certain acute neurotoxicity data that have successfully supported foreign registrations. If applicable to EPA standards these data could be submitted this year.

A.4.8	Metabolism

      870.7485	Metabolism  -  Rat 

In a study (MRID 43963301) conducted to examine the metabolism and disposition of 1-naphthaleneacetamide, five male and five female Sprague-Dawley rats were given either a single 1 or 100 mg/kg bw oral dose, or a 14-day repeated dose (1 mg/kg/day).  Groups of male and female rats were subjected to the dosing regimens above using [[14]C] ring labeled -1-naphthaleneacetamide (Batch No. 94-516-38-10; 99.7% radiochemical purity, specific activity 55.5 mCi/mmol), and nonlabeled test article (Batch No. KP 0100487, chemical purity not available).  Excretion, tissue distribution, and metabolite profiles were determined.  There were no biologically significant treatment-related effects noted during the course of the study.  Overall recovery of administered radioactivity was an excellent 97.2-101%. 1-Naphthaleneacetamide was readily absorbed and excreted within 36 hours following a single 1 mg/kg bw, a 14-day repeat oral dose of 1 mg/kg bw, or a single 100 mg/kg bw oral dose. Following single or multiple oral low doses (1 mg/kg bw) of [C[14]]-1-naphthaleneacetamide, urinary excretion accounted for 70.8-74.1% of the administered radioactivity suggesting that a multiple exposure regimen did not affect the absorption/excretion processes.  Urinary excretion was unaffected following a single 100 mg/kg dose with 66.2-69.5% of the administered radioactivity excreted in urine.  Excretion via the feces accounted for the remainder of the administered radioactivity in all treatment groups (21.6-26.2%).  Excretory patterns did not exhibit gender-related variability but reflected delayed absorption in the high-dose group.  Because tissue burdens were very low at termination, neither 1-naphthaleneacetamide nor its metabolites appear to undergo significant sequestration.  Both  urinary and fecal metabolites were quantified by HPLC and most were identified using HPLC and HPLC/MS in conjunction with known standards.  Urinary metabolism involved amide cleavage followed by glycine conjugation with the glycine conjugate being the major metabolite of the low and repeat doses (13.7-47.3% of the administered radioactivity).  The glucuronide conjugate was also a major metabolite at the low doses (4.5-7.0% of administered).  For feces, the major metabolite detected was the dihydrodiol of naphthaleneacetamide (3.6-11.3% of administered.  Parent compound was detected at low concentrations (0.7-1.9% of administered) only in feces.  Extraction efficiencies appeared to be excellent and most components in the matrices examined (urine and feces) were adequately quantified and characterized.  The available data, based upon studies using labeled 1-naphthaleneacetamide, affirmed the metabolism pathway proposed by the investigators.


In another study (MRID 43961701) conducted to examine the metabolism and disposition of 1-naphthaleneacetic acid, ethyl ester, male and female Sprague-Dawley rats were given a single 1 or 100 mg/kg bw oral dose, or a 14-day repeated dose (1 mg/kg/day).  Groups of male and female rats were subjected to the dosing regimens above using [[14]C] ring labeled -1-naphthaleneacetic acid, ethyl ester (Batch No. CSL-94-516-33-25, 99.3% radiochemical purity, specific acttivity 56.2 mCi/mmol), and nonlabeled test article (Batch No. GAB 69-34-02, chemical purity not available).  Excretion, tissue distribution, pharmacokinetic parameters, and metabolite profiles were determined.  There were no biologically significant treatment-related effects noted during the course of the study.  Overall recovery of administered radioactivity was an excellent 98.6-101.8%. 1-Naphthaleneacetic acid, ethyl ester was readily absorbed and excreted within 36 - 48 hours following a single 1 mg/kg bw, a 14-day repeat oral dose of 1 mg/kg bw, or a single 100 mg/kg bw oral dose.  Following single or multiple oral low doses (1 mg/kg bw) of [C[14]]-1-naphthaleneacetic acid, ethyl ester, urinary excretion accounted for 67.6-85.3% of the administered radioactivity.  Urinary excretion was unaffected following a single 100 mg/kg bw dose with 61.8-78% of the administered radioactivity excreted in urine.  Excretion via the feces accounted for the remainder of the administered radioactivity excreted by all treatment groups (12.3-35.2%).   Excretory patterns did not exhibit gender-related variability for the low dose groups although a minor difference was observed at the high dose.  Excretion patterns of the high-dose group reflected delayed absorption.  Because  - tissue burdens were very low at termination, neither 1-naphthaleneacetic acid, ethyl ester nor its metabolites appear to undergo significant sequestration.  Both  urinary and fecal metabolites were quantified by HPLC, TLC and most were identified using HPLC, GC/MS, and HPLC/MS in conjunction with known standards.  The major pathway of metabolism involved ester cleavage followed by glycine and glucuronide conjugation at the low and low repeat doses.  At the high dose, glucuronide conjugation appeared to play a more important role following ester cleavage.  Parent compound was detected at low concentrations (0.5-4.7% of administered) only in feces.  Extraction efficiencies appeared to be excellent and most components in the matrices examined (urine and feces) were adequately quantified and characterized.  The available data, based upon studies using labeled 1-naphthaleneacetic acid, ethyl ester, affirmed the metabolism pathway proposed by the investigators.

There are two published reports dealing with the metabolism of NAA in animals.  In one study (Dixon et al, 1977), carboxy -[14]C-1-naphthylacetic acid (aqueous equivalent NaOH solution) at 100 mg/kg was administered intramuscularly to 6 primate species (rhesus monkey: 1M, 1F; cynomolgus monkey: 1F; squirrel monkey: 2F; capuchin: 2F; marmoset: 1M and bushbaby: 1M, 1F), and intraperitoneally to cats (2F, 1M), rat (3F) and fruit bat (1F, 1M), orally to the rabbit (2F) and orally to 2 human males at 5 mg/individual.  Urine was collected for 24 hours and analyzed for radioactivity and metabolites, by liquid scintillation counting, chromatography,  radiochromatography scanning, and reverse isotope dilution.  In most species tested, 60-100% of the administered radioactivity was excreted in the urine by the end of 48 hours.  The glucuronic acid conjugate was the major urinary metabolite in man, rhesus monkey, marmoset, rabbit, rat, and fruit bat.  In the cat, no glucuronic acid conjugate was detected; turine and glycine conjugates were the major excretion products.  The 1-Naphthylacetyl glycine conjugate was a major urinary metabolite (>20%) in the cat, squirrel and bushbaby monkey and a minor metabolite in rabbit, rat, capuchia and marmoset monkey.  1-Naphthylacetylglutamine conjugate was formed only in the cynomolgus , squirrel and capuchin monkeys and marmoset in amounts not exceeding 3% of the administered dose.  1-Naphthylacetylturine was excreted by all species except the rabbit, rat  and the fruit bat.  It was a major excretion product (>6%) in the squirrel and capuchin monkeys, the marmoset and the cat.  In addition, when female rats were administered intraperitoneally doses of 5-500 mg/kg, bile duct cannulation showed that 10-44% of the radioactivity was present in the bile 3 hours after injection, while 0.6-32% was present in the urine.  At higher doses, urinary glucuronic acid predominated whereas at the lower doses the glycine conjugates predominated.  In the bile, the glucuronic acid conjugate was the major metabolite (>80% of the bile radioactivity), and the glycine conjugate was a minor metabolite (<4% of the bile radioactivity).  There was no analysis of the fecal radioactivity reported. 


In another study (Lethco and Brouwer, 1966) carboxy -[14]C-1-naphthylacetic acid metabolism was investigated in male rats.  [14]C-NAA (neutralized with NaOH) was administered orally by stomach intubation at 0.1, 1.0, 100 and 250 mg/rat (2 rats/dose, weighing 250-280 g).  Urine and feces were collected for 3 days.  For bile cannulation study, [14]C-NAA was administered orally to 8 and 7 rats (weighing 350-435 g) at 0.1 and 100 mg/ rat, respectively, and urine and bile were collected at 2 and 6 hours after administration.  Radioactivity was analyzed by liquid scintillation counting, column and paper chromatography and enzymatic analysis.  Within 3 days, 71-90% of the administered [14]C was excreted in the urine.  At the lower doses (0.1-100 mg/kg)  most of the radioactivity was excreted during the first 24 hours, while at the higher dose (250 mg/kg), excretion was highest on the second day.  Fecal excretion accounted for 3-10% at the 0.1-1.0 mg/kg doses and 14-21% of the administered dose at the 100 and 259 mg/kg doses.  After the third day, no radioactivity was detected in the feces or urine at any dose.  Fractionation of the urinary radioactivity by column chromatography and subsequent paper chromatography, UV spectral analysis and B-glucuronidase enzyme hydrolysis, revealed that 70-93% of the urinary radioactivity was NAA glycine conjugate and NAA glucuronic acid conjugate.  The glucuronic acid conjugate predominated at the two high doses and the glycine conjugate predominated at the lower dose.  Minor amounts of unchanged NAA and two other minor unidentified metabolites were also detected in the urine.  The fecal radioactivity was not characterized.  In the bile cannulation experiment, excretion  of radioactivity into the bile and urine varied by the administered dose.  At the low dose of 0.1 mg/kg radioactivity in the urine was nearly four times the radioactivity detected in the bile after 2 hours, while at the higher dose of 100 mg/kg the ratio was reversed.  At the high dose a maximum of 29% of the administered radioactivity was recovered at 6 hours, while a maximum of 54% was recovered at the low dose at 2 hours.  At the low dose, the NAA glycine conjugate was the major metabolite and the NAA glucuronic conjugate was a minor metabolite, while in the bile the preponderance of these two metabolites was reversed.  Also unchanged NAA was detected in the bile but not in the urine at both doses.  At the high dose the NAA glucuronic conjugate was the major metabolite in both urine and bile while the glycine conjugate was a minor metabolite. 

A.4.9	Immunotoxicity

	870.7800	Immunotoxicity  -  Rat

An immunotoxicity study is required.  The registrant has committed to begin this study in early 2013 and submit to EPA in early 2014.



B.  PHYSICAL/CHEMICAL PROPERTIES

Table 2.  Physicochemical Properties of NAA[1]
Parameter
                                     Value
                                   Reference
Active Ingredient
                                 NAA acetamide
Melting point/range
                                   182-184 C
Farm Chemicals Handbook
pH of 1% aqueous suspension
                                      5.1
Product CSF
Density or specific gravity
                                 0.221 g/cm[3]
Product CSF
Water solubility  (20̊C)
                                 not available

Solvent solubility (20̊C)
                                 not available
                                       
Vapor pressure at 20̊C
                                 not available
                                       
Dissociation constant (pKa)
                                 not available
                                       
Octanol/water partition coefficient (Kow)
                                 not available
                                       
UV/vis  absorption spectrum
                                 not available
                                       
Active ingredient
                                      NAA
Melting point/range
                                     130 C
Farm Chemicals Handbook
pH of 1% aqueous suspension
                                     3.45
RD D265117, 5/15/00, B. Kitchens
Density or specific gravity
                                   0.45 g/mL
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
Water solubility  (26̊C)
                                0.042 g/100 mL
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
Solvent solubility (26̊C)
                              xylene 5.5 g/100 mL
                              CCl4 1.06 g/100 mL
               freely soluble in acetone, ether, and chloroform
CB Nos. 3468 and 3469, 6/3/88, F. Suhre

Farm Chemicals Handbook
Vapor pressure at 20̊C
                               0.3 mm Hg at 26 C
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
Dissociation constant (pKa)
                                 3.16 x 10[-4]
CB Nos. 3970 and 3971, 7/5/88, F. Suhre
Octanol/water partition coefficient (Kow)
                        not applicable; polar compound

UV/vis  absorption spectrum
                                 not available
                                       
Active ingredient
                                NAA sodium salt
Melting point/range
                                   >300 C
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
pH of 1% aqueous suspension
                                      9.1
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
Density or specific gravity
                                   0.46 g/mL
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
Water solubility  (26̊C)
                                 340 g/100 mL
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
Solvent solubility (26̊C)
                        insoluble in nonpolar solvents
CB Nos. 3468 and 3469, 6/3/88, F. Suhre
Vapor pressure at 20̊C
                                 not available

Dissociation constant (pKa)
                                 3.16 x 10[-4]
CB Nos. 3970 and 3971, 7/5/88, F. Suhre
Octanol/water partition coefficient (Kow)
                        not applicable; polar compound

UV/vis  absorption spectrum
                                 not available
                                       
Active ingredient
                                NAA ethyl ester
Boiling point/range
                                   >150 C
Old unreviewed Union Carbide data
pH of 1% aqueous suspension
                                 not available

Density or specific gravity
                                 1.11 at 20 C
Old unreviewed Union Carbide data
Water solubility  (26̊C)
                                   insoluble
Old unreviewed Union Carbide data
Solvent solubility
     soluble in xylene, toluene, ethanol, acetone, and methyl ethyl ketone
Old unreviewed Union Carbide data
Vapor pressure at 20̊C
                                 not available

Dissociation constant (pKa)
                                 not available

Octanol/water partition coefficient (Kow)
                                 not available

UV/vis  absorption spectrum
                                 not available
                                       

   B. REVIEW OF HUMAN RESEARCH

Klonne, D. (1999) Integrated Report for Evaluation of Potential Exposures to Homeowners and Professional Lawn Care Operators Mixing, Loading, and Applying Granular and Liquid Pesticides to Residential Lawns:  Lab Project Number:  OMA005: OMA001: OMA002.  Unpublished study prepared by Riceerca, Inc., and Morse Laboratories.  2213 p. (MRID 44972201).
            
The PHED Task Force, 1995.  The Pesticide Handlers Exposure Database, Version 1.1.  Task Force members Health Canada, U.S. Environmental Protection Agency, and the National Agricultural Chemicals Association, released February, 1995.




