Naphthalene acetates Dietary Exposure and Risk Assessment DP #: 404399

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

MEMORANDUM

Date: March 21, 2013

SUBJECT: Naphthalene Acetates- Chronic Dietary and Drinking Water Exposure and Risk 

Assessment for Section 3 New Use of Naphthalene Acetic Acid-ester on 

Avocado, Mango, Mamey Sapote, Rambuttan, and the Expansion to Pome Fruit 

Crop Subgroup 11-10.

. 

PC Code: 056003 (NAA potassium salt) DP Barcode: D404399

Decision No.: 461439 Registration No.: 87320-E

Petition No.: 2F7991 Regulatory Action: Section 3

Risk Assessment Type: Dietary Case No.: 0379

TXR No.: NA CAS No.: 2122-70-5

MRID No.: NA 40 CFR: §180.155 (a) & (b)

FROM: Thurston G. Morton, Chemist

Risk Assessment Branch IV

Health Effects Division (7509P)

THROUGH: Dennis McNeilly, Chemist

Meheret Negussie, Chemist

Dietary Exposure Science Advisory Council (DESAC)

Health Effects Division (7509P)

TO: Tony Kish, Chemical Review Manager

Fungicide Branch

Registration Division (7505P)

This document provides chronic dietary (food and drinking water) risk analyses of exposures 

resulting from use of naphthalene acetates as plant activators on food crops. 
Naphthalene acetates Dietary Exposure and Risk Assessment DP #: 404399

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Executive Summary

Chronic dietary risk assessment was conducted for naphthalene acetates using the Dietary

Exposure Evaluation Model software with the Food Commodity Intake Database DEEM-FCID, 

Version 3.16, which incorporates consumption data from USDA’s National Health and Nutrition 

Examination Survey, What We Eat in America, (NHANES/WWEIA). This dietary survey was 

conducted from 2003 to 2008. The analysis was performed to support a Section 3 request for 

use of naphthalene acetates (NAA) on avocado, mango, and mamey sapote and the expansion of 

the Crop Subgroup 11-10.

 

Acute Dietary Exposure Results and Characterization

There were no toxicological effects attributable to a single exposure (dose) of NAA observed in 

oral toxicity studies including the developmental toxicity studies in rats or rabbits. Therefore, a 

dose and an endpoint for acute dietary exposure were not identified for NAA and a quantitative 

acute dietary exposure assessment was not conducted.

Chronic Dietary Exposure Results and Characterization

A conservative chronic dietary and drinking water exposure analysis was performed for the 

general U.S. population and various population subgroups. Tolerance level residues and 100 

percent crop treated assumptions were used. DEEM default processing factors were used to 

modify the tolerance values. The chronic analysis incorporated the 10 year average surface 

drinking water estimate from application of naphthalene acetates to olives. The chronic dietary

exposure estimate for the highest exposed population subgroup, children 1-2 years of age, is 

0.003 mg/kg/day or 2% of the cPAD. The chronic dietary exposure estimate for the general 

population is 0.0005 mg/kg/day or <1% of the cPAD. 

I. Introduction

Dietary risk assessment incorporates both exposure and toxicity of a given pesticide. 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 PAD. The PAD is equivalent to point of departure (POD, 

NOAEL, LOAEL, e.g.) divided by the required uncertainty or safety factors.

For acute and non-cancer chronic exposures, HED is concerned when estimated dietary risk 

exceeds 100% of the PAD. References which discuss the acute and chronic risk assessments in 

more detail are available on the EPA/pesticides web site: “Available Information on Assessing 

Exposure from Pesticides, A User’s Guide,” 21-JUN-2000, web link: 

http://www.epa.gov/fedrgstr/EPA-PEST/2000/July/Day-12/6061.pdf ; or see SOP 99.6 (20-

AUG-1999).

The most recent dietary risk assessment for NAA was conducted by B. Daiss (DP 397389, 

1/31/12).
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II. Residue Information

1-Naphthaleneacetic acid (NAA), its salts, ester, and acetamide are plant growth regulators 

which are collectively referred to as naphthalene acetates. They are currently registered for use 

on various orchard and fruit crops including apple, cherry, olive, orange, pear, tangelo, and 

tangerine. Naphthalene acetates are used to prevent preharvest drop of fruits, thin fruit trees, and 

delay flower induction. Tolerances for residues of naphthalene acetates in/on food and feed 

commodities are currently established under 40 CFR § 180.155, and are expressed in terms of 1-

naphthaleneacetic acid, [ethyl ester of 1-naphthaleneacetic acid, and naphthaleneacetamide]. 

The petitioner has requested Section 3 for use of naphthalene acetates on avocado, mango, and 

mamey sapote and the expansion of the Crop Subgroup 11-10. Residues used in the acute and 

chronic dietary analyses are provided in Table 1.

Table 1. Tolerance Values Used in Naphthalene Acetates Dietary Exposure Analyses

RAC Tolerance (ppm)

Pome Fruit Subgroup 11-10 0.15

Cherry, sweet 0.1

Olive 0.7

Oranges 0.1

Pineapple 0.05

Tangerine 0.1

Avocado 0.05

Potato Seed Piece 0.01

Proposed New Use Recommended Tolerance

Avocado 0.05

Mango 0.05

Mamey Sapote 0.05

Rambuttan 2.0

III. Drinking Water Data

The Tier I Estimated Drinking Water Concentrations (EDWCs) for use in the human health risk 

assessment for 1-naphthaleneacetic acid were calculated using FIRST (surface water) and 

SCIGROW (ground water) drinking water models (D293886, J.L. Melendez, 9/25/03). 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-

naphthalenacetic acid on olives, which represents the highest use rate scenario. Both models 

provide estimates suitable for screening purposes. Modeled EDWCs are presented in Table 2.
Naphthalene acetates Dietary Exposure and Risk Assessment DP #: 404399

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Table 2. Tier I Estimated Drinking Water Concentrations of 1-Naphthaleneacetic acid1

Chemical Acute (peak) Surface Water 

Concentration (ppb)

Annual Average Surface 

Water Concentration (ppb)

Ground Water 

Concentration (ppb)

NAA 22.3 2.99 0.0226

IV. DEEM-FCIDTM Program and Consumption Information

Naphthalene acetates chronic dietary exposure assessment was conducted using the Dietary

Exposure Evaluation Model software with the Food Commodity Intake Database DEEM-FCID, 

Version 3.16, which incorporates consumption data from USDA’s National Health and Nutrition 

Examination Survey, What We Eat in America, (NHANES/WWEIA). This dietary survey was 

conducted from 2003 to 2008. The data are based on the reported consumption of more than 

20,000 individuals over two non-consecutive survey days. Foods “as consumed” (e.g., apple pie) 

are linked to EPA-defined food commodities (e.g. apples, peeled fruit - cooked; fresh or N/S; 

baked; or wheat flour - cooked; fresh or N/S, baked) using publicly available recipe translation 

files developed jointly by USDA/ARS and EPA. For chronic exposure assessment, consumption 

data are averaged for the entire U.S. population and within population subgroups, but for acute 

exposure assessment are retained as individual consumption events. Based on analysis of the 

2003-2008 WWEIA consumption data, which took into account dietary patterns and survey

respondents, HED concluded that it is most appropriate to report risk for the following 

population subgroups: the general U.S. population, all infants (<1 year old), children 1-2, 

children 3-5, children 6-12, youth 13-19, adults 20-49, females 13-49, and adults 50-99 years 

old.

For chronic dietary exposure assessment, an estimate of the residue level in each food or foodform (e.g., orange or orange juice) on the food commodity residue list is multiplied by the 

average daily consumption estimate for that food/food form to produce a residue intake estimate. 

The resulting residue intake estimate for each food/food form is summed with the residue intake 

estimates for all other food/food forms on the commodity residue list to arrive at the total 

average estimated exposure. Exposure is expressed in mg/kg body weight/day and as a percent 

of the cPAD. This procedure is performed for each population subgroup.

V. Toxicological Information

HED evaluated the toxicology data base for naphthalene acetates and selected the following doses 

and endpoints for acute and chronic dietary and drinking water risk assessments. 
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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. 

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). 

FQPA SF = FQPA Safety Factor. 

PAD = population adjusted dose (a = acute, c = chronic). 

RfD = reference dose. 

VI. Results/Discussion

As stated above, for chronic assessments, HED is concerned when dietary risk exceeds 100% of 

the PAD. The DEEM-FCIDTM analyses estimate the dietary exposure of the U.S. population and 

various population subgroups. The results reported in Table 4 are for the general U.S. 

Population, all infants (<1 year old), children 1-2, children 3-5, children 6-12, youth 13-19, 

females 13-49, adults 20-49, and adults 50-99 years.

Table 3. Summary of Toxicological Doses and Endpoints for Naphthalene acetates for Use in Dietary and NonOccupational 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 

emesis, corpuscular regurgitation 

incidences, gross and histopathological 

changes in stomachs and sinusiodal 

histiocytosis in livers in males

Cancer (all 

routes)

Not a Human Carcinogen
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Results of Chronic Dietary Exposure Analysis

Table 4. 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

0.000513 <1

All Infants (< 1 year old) 0.001487 1.0

Children 1-2 years old 0.002945 2.0

Children 3-5 years old 0.001868 1.2

Children 6-12 years old 0.000774 <1

Youth 13-19 years old 0.000383 <1

Adults 20-49 years old 0.000305 <1

Adults 50-99 years old 0.000303 <1

Females 13-49 years old 0.000317 <1

VI. Characterization of Inputs/Outputs

The chronic dietary analysis is conservative. Tolerance level residues used in the analysis are 

expected to exceed the residues actually consumed. In addition, the 100% crop treated estimate 

used for all crops in the assessment will considerably overestimate the actual percent crop 

treated. 

VII. Conclusions

Based on screening level 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. The chronic 

dietary exposure estimate for the highest exposed population subgroup, children 1-2 years of age, 

is 0.003 mg/kg/day or 2% of the cPAD. 

VIII. List of Attachments

1. Chronic DEEM-FCID Residue Input File.

2. Results of Chronic DEEM-FCID Dietary Exposure Analysis.
Naphthalene acetates Dietary Exposure and Risk Assessment DP #: 404399

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Attachment 1 Chronic DEEM-FCID Residue Input File

Filename: C:\Documents and Settings\tmorton\My Documents\MyFiles\DEEM Files\056003 

NAA\2E7991\056003 Chronic 2F7991.R08

Chemical: NAA

RfD(Chronic): .15 mg/kg bw/day NOEL(Chronic): 0 mg/kg bw/day

RfD(Acute): 0 mg/kg bw/day NOEL(Acute): 0 mg/kg bw/day

Date created/last modified: 10-24-2012/10:08:49 Program ver. 3.16, 03-08-d

-----------------------------------------------------------------------------------

 EPA Crop Def Res Adj.Factors Comment

 Code Grp Commodity Name (ppm) #1 #2 

---------- ---- ------------------------------- ---------- ------ ------ -------

0103296000 1C Potato, chips 0.010000 1.000 1.000 

0103297000 1C Potato, dry (granules/ flakes) 0.010000 6.500 1.000 

0103297001 1C Potato, dry (granules/ flakes)-b 0.010000 6.500 1.000 

0103298000 1C Potato, flour 0.010000 1.000 1.000 

0103298001 1C Potato, flour-babyfood 0.010000 1.000 1.000 

0103299000 1C Potato, tuber, w/peel 0.010000 1.000 1.000 

0103299001 1C Potato, tuber, w/peel-babyfood 0.010000 1.000 1.000 

0103300000 1C Potato, tuber, w/o peel 0.010000 1.000 1.000 

0103300001 1C Potato, tuber, w/o peel-babyfood 0.010000 1.000 1.000 

1001240000 10A Orange 0.100000 1.000 1.000 

1001241000 10A Orange, juice 0.100000 1.800 1.000 

1001241001 10A Orange, juice-babyfood 0.100000 1.800 1.000 

1001242000 10A Orange, peel 0.100000 1.000 1.000 

1001369000 10A Tangerine 0.100000 1.000 1.000 

1001370000 10A Tangerine, juice 0.100000 2.300 1.000 

1100007000 11 Apple, fruit with peel 0.150000 1.000 1.000 

1100008000 11 Apple, peeled fruit 0.150000 1.000 1.000 

1100008001 11 Apple, peeled fruit-babyfood 0.150000 1.000 1.000 

1100009000 11 Apple, dried 0.150000 8.000 1.000 

1100009001 11 Apple, dried-babyfood 0.150000 8.000 1.000 

1100010000 11 Apple, juice 0.150000 1.300 1.000 

1100010001 11 Apple, juice-babyfood 0.150000 1.300 1.000 

1100011000 11 Apple, sauce 0.150000 1.000 1.000 

1100011001 11 Apple, sauce-babyfood 0.150000 1.000 1.000 

1100129000 11 Crabapple 0.150000 1.000 1.000 

1100173500 11 Goji berry 0.150000 1.000 1.000 

1100210000 11 Loquat 0.150000 1.000 1.000 

1100266000 11 Pear 0.150000 1.000 1.000 

1100266001 11 Pear-babyfood 0.150000 1.000 1.000 

1100267000 11 Pear, dried 0.150000 6.250 1.000 

1100268000 11 Pear, juice 0.150000 1.000 1.000 

1100268001 11 Pear, juice-babyfood 0.150000 1.000 1.000 

1100310000 11 Quince 0.150000 1.000 1.000 

1201090000 12A Cherry 0.100000 1.000 1.000 

1201090001 12A Cherry-babyfood 0.100000 1.000 1.000 

1201091000 12A Cherry, juice 0.100000 1.500 1.000 

1201091001 12A Cherry, juice-babyfood 0.100000 1.500 1.000 

8601000000 86A Water, direct, all sources 0.003000 1.000 1.000 

8602000000 86B Water, indirect, all sources 0.003000 1.000 1.000 

9500020000 O Avocado 0.050000 1.000 1.000 

9500215000 O Mango 0.050000 1.000 1.000 

9500215001 O Mango-babyfood 0.050000 1.000 1.000 

9500216000 O Mango, dried 0.050000 1.000 1.000 

9500217000 O Mango, juice 0.050000 1.000 1.000 

9500217001 O Mango, juice-babyfood 0.050000 1.000 1.000 

9500235000 O Olive 0.700000 1.000 1.000 

9500236000 O Olive, oil 0.700000 1.000 1.000 

9500279000 O Pineapple 0.050000 1.000 1.000 

9500279001 O Pineapple-babyfood 0.050000 1.000 1.000 

9500280000 O Pineapple, dried 0.050000 5.000 1.000 

9500281000 O Pineapple, juice 0.050000 1.700 1.000 

9500281001 O Pineapple, juice-babyfood 0.050000 1.700 1.000 

9500333000 O Sapote, Mamey 0.050000 1.000 1.000 
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Attachment 2 Results of Chronic DEEM-FCID Dietary Exposure Analysis

U.S. EPA Ver. 3.16, 03-08-d

DEEM-FCID Chronic analysis for NAA NHANES 2003-2008 2-day

Residue file name: C:\Documents and Settings\tmorton\My Documents\MyFiles\DEEM Files\056003 

NAA\2E7991\056003 Chronic 2F7991.R08

 Adjustment factor #2 NOT used.

Analysis Date 10-24-2012/10:24:55 Residue file dated: 10-24-2012/10:12:06

Reference dose (RfD, Chronic) = .15 mg/kg bw/day

===============================================================================

 Total exposure by population subgroup

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 Total Exposure

 -----------------------------------

 Population mg/kg Percent of 

 Subgroup body wt/day Rfd 

-------------------------------------- ------------- ----------------

Total US Population 0.000513 0.3%

Hispanic 0.000735 0.5%

Non-Hisp-White 0.000448 0.3%

Non-Hisp-Black 0.000597 0.4%

Non-Hisp-Other 0.000600 0.4%

Nursing Infants 0.000880 0.6%

Non-Nursing Infants 0.001757 1.2%

Female 13+ PREG 0.000544 0.4%

Children 1-6 0.002154 1.4%

Children 7-12 0.000682 0.5%

Male 13-19 0.000396 0.3%

Female 13-19/NP 0.000369 0.2%

Male 20+ 0.000299 0.2%

Female 20+/NP 0.000302 0.2%

Seniors 55+ 0.000304 0.2%

All Infants 0.001487 1.0%

Female 13-50 0.000320 0.2%

Children 1-2 0.002945 2.0%

Children 3-5 0.001868 1.2%

Children 6-12 0.000774 0.5%

Youth 13-19 0.000383 0.3%

Adults 20-49 0.000305 0.2%

Adults 50-99 0.000303 0.2%

Female 13-49 0.000317 0.2%

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