### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON

, D

. C

. 20 46 0



### MEM O RANDUM

D a t e : 04

- FEB-2016 OF F ICE OF CHEM I CAL SAFETY A N D POLLUTION PREVE N T I ON



### SUBJECT: T ricl o p yr. Human Health Ri s k Assessment for Petition to Amend Tolerance Express i ons to Include Triclopyr C h oline Salt; and Petition to R emove Grazing

R est ri c tion s fo r Dairy Catt l e.

P C Codes: 1 1 6000, 11 600 I. 116002. 116004
Deci s i o n Nos.: 491435. 4884 78 OP Bar co de s : 042077 1

. 0426071
Re g i s trat i on Nos.: 62719-37

, 627 1 9-53. 62719-87, 627 1 9 -55 2, 62719-
637. 62719

- AIT (6 87 ) Peti t ion Nos.: 4F8249 and 4 F8279 R eg u l atory Act i on: Section 3
Risk Assessment T y pe: Si n gle Chemica l Aggregat e TXRNo.: A Case No

. : 2710
CAS Nos.: 55335-06-3

. 572 1 3-69-1. 64700 -56- 7

. 1048373-85-8
40 C F'R : § 180.417 MRID No.: A



### F R OM: J ennifer R. Tyler

, Chemist 

## rLata Venkates hwara

, En vi ronm e nta l Sc i e nti st 

### L """./-;&... 

### V

......,..._ I. h...- ' l..._ 

### Monique M

. P erro n , Sc. D

., Toxicolog i st

## f"&~**~..__** Ri sk Assess m ent Branch 1 (RAB I 

### ) / Health Effects l)ivision ( H E D ; 7509P)



### THR O U GH : Charles W. Smith Ill

, Branch Ch i ef George F. Kramer, Ph.D.

, Senior**Chemis ~~~~~:;:::s_s~-::;:a--**  

### RAB 1/H ED (7509 P )



### TO: Mindy O ndi s h

, Risk Reviewer

R eube n Baris

, Product Man age r 25

H e r bicide Branc h ( HB )

R eg i stration Di vision (RD, 7505P)

The HED of the Office of Pesticide P rograms (O PP ) i s c h arged w i th estimat i ng the risk to human
health from exposure t o pesticides. T he RD of OPP has requested that HED evaluate hazard and

expos ure data and conduct dietary

, occupational, r es idential and aggregate exposure assessments,

as needed

, to estimate the risk to human health that wi ll result from propo se d and c urr ent l y registered us es of the active in g redient (a i) triclopyr (2-[(3,5,6 -tr ic hl o r o-2-pyridi n y l )oxy ]acetic acid). Dow AgroSc i e n ces ha s su bmitted 1 ) a petition t o amend th e tolerance exp r essio n s for triclopyr to include a new fonn u l ation, triclopyr c h ol in e sa lt (PP # 4F8279); and 2) a petition to

remove the grazing re s triction for lactating dairy cattle

, and estab li sh a tol e rance for residues in
milk

, fat (0

. 70 ppm ) as we ll as increased tolerances for residues in milk (0.60 ppm), meat (0.08 ppm)

, fat 

### (0 .09 ppm ), a n d meat b ypro ducts (0.70 ppm) ( PP # 4F8249). The risk assessment

, residue chemistry r eview and dietary exposure assessment were provided by Jennifer T yler ( RAB 1 ); the hazard characterization by Monique Perron (RA B l ); the occupational/resident i al

expos ur e assess m ent by Lata Venkateshwara ( RAB I ); 

### and the drinking water assessme nt by Larry Liu of t h e Env i ron m enta l Fate and Effects Division (EFE D ).

Pa ge I of37Triclopyr Human Health Risk Assessment DP# D426071

Page 2 of 37 

### TABLE OF CONTENTS

1.0 Executive Summary

................................ ................................ ................................ ............. 3
2.0 HED Recommendations

................................ ................................ ................................ ....... 6
2.1 Data Deficiencies

................................ ................................ ................................ ............. 7
2.2 Tolerance Considerations

................................ ................................ ................................ . 7
2.3 Label Recommendations

................................ ................................ ................................ .. 8
3.0 Introduction

................................ ................................ ................................ .......................... 8
3.1 Chemical Identity

................................ ................................ ................................ ............. 9
3.2 Physical/Chemical Characteristics

................................ ................................ ................. 10
3.3 Pesticide Use Pattern

................................ ................................ ................................ ...... 10
3.4 Anticipated Exposure Pathways

................................ ................................ ..................... 11
3.5 Consideration of Environmental Justice

................................ ................................ ........ 11
4.0 Hazard Characterization and Dose

- Response Assessmen t

................................ ................ 12
4.1 Toxicology Studies Available for Analysis

................................ ................................ ... 12
4.2 Absorption, Distribution, Metabolism, & Elimination (ADME)

................................ ... 12
4.3 Toxicological Effects

................................ ................................ ................................ ..... 13
4.4 Safety Factor for Infants and Children (FQPA Safety Factor)

................................ ....... 13
4.5 T oxicity Endpoint and Point of Departure Selections

................................ .................... 14
5.0 Dietary Exposure and Risk Assessment

................................ ................................ ............ 17
5.1 Residues of Concern Summary and Rationale

................................ ............................... 18
5.2 Food Residue Profile

................................ ................................ ................................ ...... 18
5.3 Water Residue Profile

................................ ................................ ................................ .... 19
5.4 Dietary Risk Assessment

................................ ................................ ................................ 19
6.0 Residential (Non

- Occupational) Exposure/Risk Characterization

................................ .... 21
6.1 Residential Handler Expos ure

................................ ................................ ........................ 21
6.2 Post

- Application Exposure

................................ ................................ ............................. 22
6.3 Residential Risk Estimate s for Use in Aggregate Assessment

................................ ...... 23
6.4 Residential Bystander Post

- application Inhalation Exposure

................................ ........ 25
6.5 Spray Drift

................................ ................................ ................................ ...................... 25
7.0 Aggregate Exposure/Risk Characterization

................................ ................................ ....... 25
7.1 Acute Aggregate Risk

................................ ................................ ................................ .... 26
7.2 Short

- and Intermediate

- Term Aggregate Risk

................................ .............................. 26
7.3 Chronic Aggregate Risk

................................ ................................ ................................ . 27
8.0 Cumulative Exposure/Risk Characterization

................................ ................................ ..... 27
9.0 Occupational Exposure/Risk Characterization

................................ ................................ .. 28 Attachment 1. Toxicology Profile and Executive Summaries.

................................ .................... 29
A.1 Toxicology Data Requirements

................................ ................................ ...................... 29
A.2 Toxicity Profiles

................................ ................................ ................................ ............. 30 Attachment 2. Summary of US and International Tolerances and Maximum Res idue Limits.

.. 34 Attachment 3. Summary of Updated Occupational Handler Inhalation Exposure and Risk Estimates for July 2014 HASPOC Meeting.

................................ ................................ ................. 35Triclopyr Human Health Risk Assessment DP# D426071

Page 3 of 37 

### 1.0 Executive Summary

Dow AgroSciences has submitted 1) a petition to amend the tolerance expressions for triclopyr to include a new formulation, triclopyr choline salt (PP# 4F8279); and 2) a petition to remove the grazing restriction for lactating dairy cattle, and establish a tol erance for residues in milk, fat (0.70 ppm) as well as increased tolerances for residues in milk (0.60 ppm), meat (0.08 ppm), fat (0.09 ppm), and meat byproducts (0.7 0 ppm) (PP# 4F8249).

Triclopyr is a selective herbicide belonging to the pyridinoxy acid class of chemicals. It is currently registered in the U.S. for use on rice as well as several non

- agricultural use sites including rights

- of

- way, pasture and rangelands, forests, and turf, including home lawns. It is also used to control aquatic weeds gr owing in lakes, ponds, reservoirs, and wetlands, and to control woody brush and herbaceous weeds in wetlands and on the banks and shores of aquatic
sites.

Currently, permanent tolerances are established for the combined residues of triclopyr per se , as a result of the application/use of butoxyethyl ester of triclopyr and triethylamine salt of triclopyr, in or on eggs; fish; grass forage and hay; milk; poultry fat, meat, and meat byproducts, except kidney; rice, grain and straw; and shellfish [40 CFR §180 .417 (a)(1)]. In addition, permanent tolerances are established for residues of triclopyr acetic acid and its metabolite 3,5,6

- trichloro

- 2

- pyridinol ( TCP ) , as a result of the application/use of butoxyethyl ester of triclopyr and triethylamine salt of tric lopyr, in or on the meat, fat, and meat byproducts of cattle, goats, hogs, horses, and sheep [40 CFR §180.417 (a)(2)].

A scoping document to support Registration Review of triclopyr, triethylamine salt (TEA); and triclopyr, butoxyethyl ester (BEE) was completed on 12

- NOV

- 2014 (Memo, J. Tyler et al. ; D417817). The most recent quantitative human health risk assessment was performed in 2002 in conjunction with the use of triclopyr on aquatic sites ( Memo, W. Donovan et al. , 24

- JUL

- 2002; D263770). Risk ass essment and characterization of the metabolite TCP derived from multiple
chemicals have been assessed in a separate document (Memo, W. Donovan et al. , 06

- JUN

- 2002, D283101). The conclusions of the 2002 TCP assessment that acute and chronic dietary

aggrega te exposure estimates are below HED’s level of concern ) are still considered valid.

Toxicity Profile : The toxicological database for triclopyr is adequate for hazard characterization, toxicity endpoint selection, and Food Quality Protection Act (FQPA) S afety F actor (SF) evaluation. Waivers have been submitted by the registrant for the acute neurotoxicity (ACN) and subchronic inhalation studies. The HED Hazard and Science Policy Council (HASPOC) discussed the need for these studies using a weight

- of

- ev idence (WOE) approach (J. Leshin; TXR# 0057009). HASPOC concluded that the ACN is not required at this time. The subchronic inhalation study is required at this time and an additional 10X database uncertainty factor (UF DB 

### ) will be applied for lack of the study when assessing inhalation exposure scenarios.

Overall, effects in the triclopyr database were indicative of kidney and liver toxicity in rats and dogs, respectively. The primary effect observed in rats was degeneration of the proximal tubule,
whic h was seen at approximately the same dose (20

- 28 mg/kg/day) in the subchronic oral and

two

- generation reproduction toxicity studies. Body

- weight decrements were also noted in rats in the subchronic neurotoxicity and immunotoxicity studies at much higher doses (200

- 250 mg/kg/day). In dogs, liver toxicity was evidenced by increased liver enzymes, increase liver weights, and liver histopatholo gy at a similar dose as rat effects (20 mg/kg/day). Changes inTriclopyr Human Health Risk Assessment DP# D426071

Page 4 of 37 

### hematological parameters (decreased packed cell volume, decreased hemoglobin, and decreased red blood cell count) were also observed in dogs at the same dose.

There is evidence of increas ed qualitative susceptibility to offspring from triclopyr exposure in
the rat two

- generation reproduction study based on increased incidence of rare pup malformations observed in the presence of parental toxicity. There is also potential qualitative

susce ptibility in the rat developmental toxicity study; however, the evidence was not as conclusive as the reproduction toxicity study. Concern is low since effects are well

characterized with clearly established no

- observed adverse

- effect level/ lowest

- observe d adverse

effect level (NOAEL/LOAEL) values, effects were seen in the presence of parental toxicity, and selected endpoints are protective of the observed effects.

Dose

- response and FQPA Assessment : The triclopyr risk assessment team has evaluated the
ha zard and exposure data; and, based on these data, recommended that the FQPA SF be reduced to 1X for all exposure scenarios except inhalation based on the following considerations outlined in more detail in the sections below: (1) the toxicology database f or triclopyr is adequate for FQPA SF consideration; (2) there is no evidence of neurotoxicity from triclopyr exposure; (3) selected endpoints are protective of any observed pre

- or post

- natal offspring susceptibility; and (4) the exposure databases are suf ficient and unlikely to underestimate exposure

For inhalation exposures, the FQPA SF has been retained at 10X to incorporate the UF DB 

### for lack of a subchronic inhalation study.

Residue Chemistry : The qualitative nature of the residue in rice, grass, fis h, shellfish, and livestock is adequately understood based on the available metabolism studies. Adequate
methods are available for tolerance en forcement and data collection. The available residue chemistry data support the request to 1) amend the toleran ce expression for triclopyr to include a new formulation, triclopyr choline salt; and 2) the removal of the grazing restriction for lactating dairy cattle as well as establishment of the following per manent tolerances: milk at 0.60 ppm; meat of cattle, go ats, horses, hogs, and sheep at 0.10 ppm; fat of cattle, goats, horses, hogs, and sheep at 0.10 ppm; and meat byproducts of cattle, goats , horses, hogs, and sheep at 0.5 0 ppm

.

Drinking Water Exposure and Risk : A revised drinking water assessment was not required since the proposed uses will not have an effect on the concentration of triclopyr in drinking water. EFED provided estimated drinking water concentrations (EDW Cs ) for triclopyr based on the registered a quatic use (Memo s , L. Liu, 0 4

- JUN

- 2015, D419489; M. Mahoney, 17

- JUN

- 2002, D283715). T he EDWCs of triclopyr for surface water are estimated to be 1,049 parts per billion (ppb) for acute (peak) exposures and 390 ppb for chronic (annual average) exposures. EPA calculated and required setback distances from the application site to the functional potable water intake in order to maintain average drinking water concentration levels below 400 ppb. Furthermore, since potable water intakes are required to be turn ed off until triclopyr concentration levels are below 400 ppb, EPA has determined that for acute and chronic dietary risk assessments, the water concentration value of 400 ppb is appropriate to use to assess the contribution to drinking water

.

Dietary Exp osure and Risk : Acute and chronic dietary exposure assessments were conducted using the using the Dietary Exposure Evaluation Model software with the Food Commodity
Intake Data base (DEEM

- FCID) Version 3.16.Triclopyr Human Health Risk Assessment DP# D426071

Page 5 of 37 

### The acute dietary analysi s assumed default processing factors (as necessary), tolerance

- level residues, 100% crop treated (CT) for all co mmodities and EDWCs ( 400 ppb ) for dire ct and
indirect water sources. For females 13

- 49 years old, the resulting acute ( food and drinking

water ) risk e stimate is not of concern to HED [ < 100% of the acute population

- adjusted dose ( aPAD) ] at the 95 th 

### percentile of the exposure distribution ( 53 % of the aPAD). For the general U.S. population and all other population subgroups, the resulting acute food and drinking water
risk estimates are not of concern to HED (< 100% aPAD) at the 95 th 

### percentile of the exposure distribution. The most highly expos ed population subgroup , excluding females 13

- 49 years old,
is all infants (<1 year old) at 8 % of the aPAD. It should be noted that females 13

- 49 years old have a lower aPAD (0.05 mg /kg/day) than the general U.S. population and all other population subgrou ps (1.0 mg/kg/day). As a result, even though the exposure estimate for females 13

- 49 years old was lower than the estimate for the general U.S. population, females 13

- 49 years old have the highest risk estimate.

The chronic dietary analysis assumed defa ult processing factors (as necessary), tolerance

- level residues for all commodities except milk, 100% CT for all commodities and EDWCs (400 ppb) for direct and indirect water sources. An anticipated residue (AR) calculated from a recently
submitted livest ock feeding study was used for milk. The resulting chronic (food and drinking water) risk estim ates are not of concern to HED [ <100% of the chronic population

- adjusted dose ( cPAD) ] for general U.S. population and all population subgroups. The most highly exposed population subgroup is all infants (<1 year old) at 4 6 % of the cPAD.

Residential Exposure : The proposed uses do not involve applications by homeowners or commercial applicators in residential settings ; therefore, no new residential exposure s are expected. However, there are existing residential uses that have been reassessed in this document to reflect updates to HED’s 2012 Residential standard operating procedures (SOPs) along with policy changes for body

- weight assumptions.

The results of the residential handler exposure and risk assessment indicate that short

- term inhalation risks are not of concern [margins of exposure ( MOEs ) ≥ 1000] for all turf scenarios.
Short

- term incidental oral post

- application risk estimates for all turf scenarios are not of concern to HED (i.e., MOEs ≥ 100). Short

- term incidental oral post

- application risk estimates are protective of intermediate

- term because the poi nt of departure (POD) and level of concern (LOC) are the same.

Short

- term inhalation post

- application risk estimates for all swimmer scenarios are not of concern to HED (i.e., MOEs ≥ 1000). Furthermore, short

- term inhalation post

- application risk
estim ates are protective of intermediate

- term because the POD is the same. The post

- application ingestion risk estimates for swimmers are also not of concern to HED (i.e., MOEs ≥ 100).

Aggregate Risk : For the proposed uses, human health aggregate risk assess ments have been conducted for the following exposure scenarios: acute aggregate exposure (food + drinking water), short

- term aggregate exposure (food + drinking water + residential), and chronic aggregate exposure (food + drinking water). Although there are intermediate

- term residential exposures, an intermediate

- term aggregate was not quantitatively assessed since (1) the short

and intermediate

- term PODs /LOCs are the same and (2) the short

- term aggregate provides a

worst

- case estimate of residential exp osure. For these reasons, the short

- term aggregate is protective of the longer

- term exposures. A cancer aggregate risk assessment was not performed
because triclopyr is not carcinogenic. All potential exposure pathways were assessed in theTriclopyr Human Health Risk Assessment DP# D426071

Page 6 of 37 

### aggregate ris k assessment as a conservati ve, health

- protective measure. All aggregate risk
estimates are not of concern to HED for the scenarios listed above.

Occupational Exposure/Risk : The proposed action to remove a grazing restriction for dairy
cattle is not e xpected to result in additional occupational exposures; and the proposed registration of the choline salt is covered by the previous actions. No new occupational assessments have
been conducted. However, occupational handler inhalation exposure and risk estimates were updated to reflect all of the currently registered uses of triclopyr for the July 2014 HASPOC meeting in order to assess the inhalation waiver request submitted by the triclopyr registrants. A summary of the occupational handler inhalation risk estimates from these uses of triclopyr are presented in Attachment 3

.

Environmental Justice Considerations : 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.archives.gov/federal

- register/executive

orders/pdf/12898.pdf

.

Review of Human Research : This exposure/risk assessment relies in p art on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical. These data, which include studies from the Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1); the Outdoor Residential Exposure Ta sk Force (ORETF) database; the Agricultural Re

- entry Task Force (ARTF) database, are subject to ethics review pursuant to 40 CFR 26, have received that review, and are compliant with applicable ethics requ irements. For certain studies, that review may hav e included review by the Human Studies Review Board. Descriptions of data sources as well as guidance on their use can be found at http://www2.epa.gov/pesticide

- science

- and

- assessing

- pesticide

- risks/occupational

- pesticide

handler

- exposure

- data and http://www2.epa.gov/pesticide

- science

- and

- assessing

- pesticide

risks/occupational

- pesticide

- post

- application

- exposure

.

2.0 HED Recommendations

Provided a revised Section F is submitted, H ED concludes that the toxicological, residue chemistry and occupatio nal/residential databases support 1) the petition to amend the tolerance expressions for triclopyr to include a new formulation, triclopyr choline salt (PP# 4F8279); and 2) the petition to remove the grazing restriction for lactating d airy cattle, and esta blish tolerances (PP# 4F8249) as listed in Section 2.2.2. HED is not recommen ding for any label modifications in conjunction with this petition.

The proposed action to remove a grazing restriction for dairy cattle is not expected to result in
additional occupational exposures; and the proposed registration of the choline salt is covered by the previous actions. No new occupational assessments have been conducted. However, occupational handler inhalation exposure and risk estimates were updated to reflec t all of the currently registered uses of triclopyr for the July 2014 HASPOC meeting in order to assess the inhalation waiver request submitted by the triclopyr registrants. Based on a WOE approach, t he
HASPOC concluded that a subchronic inhalation study is required at this time and an additional 10X database uncertainty factor will be applied for lack of the study when assessing inhalation exposure scenarios

.Triclopyr Human Health Risk Assessment DP# D426071

Page 7 of 37 

### 2.1 Data Deficiencies

Toxicology

• 870.3465: Subchronic Inhalation Toxicity Study.

Residue Chemistry

• 860.1550: Revised Section F (see Section 2.2.2).

2.2 Tolerance Considerations

2.2.1 Enforcement Analytical Method

Adequate methods are available for tolerance enforcement and data collection. Two gas chromatography methods (Methods I and II) with electron

- capture detection (GC/ECD) are available for the determination of triclopyr residues of concern. Method I (Dow Chemical Co. Method ACR 77.4) separately determines residues of triclopyr, 3,5,6

- trichloro

- 2

- pyridinol, and
2

- methoxy

- 3,5 ,6

- trichloropyridine and has successfully undergone an Agency method validation using grass commodities. Method II (Dow Chemical Co. Method ACR 77.2) determines residues of triclopyr per se in milk, cream, and tissues, and has detection limits of 0.05

- 0.1 ppm.

The Food and Drug Administration (FDA) PESTDATA database dated 1/94 (PAM Vol. I, Appendix I) indicates that triclopyr is completely recovered (>80%) using multiresidue method PAM Vol. I Section 402. Data pertaining to multiresidue methods testing o f triclopyr and its metabolites through Protocols B, C, D, and E have been submitted and forwarded to FDA.

2.2. 2 Recommended Tolerances

40 CFR §180.417(a) should be updated to state the following tolerance expression:

40 CFR 180.417(a)(1): “Tolerances are established for residues of the herbicide triclopyr, including its metabolites and degradates, in or on the commodities in the table below resulting from the application of the butoxyethyl ester of triclopyr, triethyla mine salt of triclopyr, or choline salt of triclopyr. Compliance with the tolerance levels specified below is to be determined by measuring only triclopyr (2

- [(3,5,6

- trichloro

- 2

- pyridinyl)oxy]acetic acid). ”

40 CFR 180.417(a)(2): Tolerances are established for residues of the herbicide triclopyr, including its metabolites and degradates, in or on the commodities in the table below resulting from the application of the butoxyethyl ester of triclopyr, triethylamine salt of triclopyr, or choline salt of triclo pyr. Compliance with the tolerance levels specified below is to be determined by measuring the combined residues of triclopyr (2

- [(3,5,6

- trichloro

- 2

- pyridinyl)oxy]acetic acid) and its metabolite 3,5,6

- trichloro

- 2

- pyridinol (TCP), calculated as the stoichio metric equivalent of triclopyr.”Triclopyr Human Health Risk Assessment DP# D426071

Page 8 of 37 Table 2.2.2. Tolerance Summary for Triclopyr.

Commodity Established
Tolerance

(ppm) Proposed
Tolerance

(ppm) Recommended Tolerance (ppm) Comments Correct Commodity Definition
Milk 1 0.01 0.60 0.60 Milk, fat 1

- 0.70

- M eat 2,3 0.05 0.08 0.10

Fat 2,3 0.05 0.09 0.10
Liver 2,3 0.5

- NA Kidney 2,3 0.5

- NA Meat byproducts, except kidney and liver 2,3 0.05

- NA Meat byproducts 2,3

- 0.7 0 0.50

1. Triclopyr only.
2. Triclopyr and TCP.
3. M eat fat, liver, kidney

, and meat byproducts of cattle, goat s , horse s , hogs, and sheep.



### 2.2. 3 Revisions to Petitioned

- For Tolerances

HED is recommending to increase the proposed tolerances for m eat

, fat, and meat byproducts of cattle, goats, horses, hogs, and sheep and lower the meat byproducts tolerance from what has been proposed in order to harmonize with established Canadian maximum residue limits (MRLs) . Based on the available residue chemistry data, HED has determined that a tolerance for milk fat is not required. The current tolerance s for liver (0.5 ppm), kidney (0.5 ppm), and meat byproducts, except liver and kidney (0.05 ppm) of cattle, goats, horses, hogs, and sheep should
be deleted from 40 CFR §180.417 (a)(2)

.

2.2.4 International Harmonization

The current U.S. tolerances and Canadian MRLs for milk are summarized in Attachment 2

. The
recommended U.S. tolerances are ha rmonized with Canadian MRLs for livestock meat, fat, and meat byproducts

. During Registration Review, HED will consider the possibility of ha rmonizing with Canada for the commodities with differing tolerances.

2.3 Label Recommendations

HED is not recommending for any changes to the proposed label.

3.0 In troduction

Triclopyr products are used as selective herbicides to control broadleaf wee ds and woody brush

. Triclopyr products are registered for use on rice as well as a variety of non

- agricultural sites including rights of way, pasture and rangelands, forests, rice, and turf (including home lawns), golf courses, cemeteries, parks, lakes, b ayous, ponds, reservoirs, marshes, roadsides, fence rows, canals, ditch banks, athletic fields, storage yards, industrial sites, trails, patios, camp areas, homes and cabins (outdoor), and Christmas tree plantings.Triclopyr Human Health Risk Assessment DP# D426071

Page 9 of 37 

### 3.1 Chemical Identity

Table 3.1. Test Compound Nomenclature. Compound

Common name Triclopyr

IUPAC name 3,5,6

- trichloro

- 2

- pyridyloxyacetic acid

CAS n a me 2

- [(3,5,6

- trichloro

- 2

- pyridinyl)oxy]acetic acid CAS registry number 55335

- 06

- 3 Compound

Common name Triclopyr TEA

Chemical name Triclopyr, triethylamine salt CAS registry number 57213

- 69

- 1 Compound

Common name Triclopyr BEE

Chemical name Triclopyr, Butoxyethyl Ester CAS registry number 64700

- 56

- 7 Compound

Common name Triclopyr choline salt

Chemical name Triclopyr choline salt CAS registry number 1048373

- 85

- 8Triclopyr Human Health Risk Assessment DP# D426071

Page 10 of 37 

### 3.2 Physical/Chemical Characteristics

T able 3.2 . Physicochemical Properties of the Technical Grade Test Compound Triclopyr.

Parameter Value Reference Melting range 148

- 150 ° C

RD Memorandum, S. Mathur

, 10

- OCT

- 2001; D276420 pH 3.03 ± 0.01 at 25 C Density 0.308 g/mL at 20 ° C Water solubility 0.408 g/L at 20 ° C Solvent solubility 581 g/L in acetone 655 g/L in methanol
Vapor pressure 1.5 x 10

- 6 torr at 25 ° C Dissociation constant, pK a Not available Octanol/water partition coefficient log K ow = 0.42 (pH 5) UV/visible absorption spectrum Not available



### 3.3 Pesticide Use Pattern

Proposed Use : Dow AgroSciences has submitted a petition to remove the grazing restriction for lactating dairy cattle on several registered labels for triclopyr (see Table 3.3 .1 ).

Table 3.3. 1. Summary of Existing and Proposed Grazing Restrictions for Triclopyr.

Use Site Formulation (EPA Reg. No.) Existing Use
Directions and

Limitations Proposed Use Directions and
Limitations

Land Grazed by Lactating Dairy Animals (Rangelands, Pastures, CRP Acres, Non

- Crop Areas, Forestry) TEA MUP (EPA Reg. No. 62719

- 53) BEE MUP (EPA Reg. No. 62719

- 87)
Garlon ® 3A (EPA Reg. No. 62719

- 37) Remedy ® Ultra (EPA Reg. No. 62719

- 552)
PastureGard ® HL (EPA Reg. No. 62719

- 637) Do not allow lactating dairy animals to graze
treated areas until the next growing season.

PHI (hay): 14 days. Grazing or harvesting green forage: There are no grazing or haying

r estrictions for livestock including dairy animals on treated area.

Haying (harvesting of dried forage): Do not harvest within 14 days after application.



### Registered Residential Uses : Triclopyr is registered for use on several terrestrial non

- agricultural use sites including rights

- of

- way, pasture and rangelands, forests, and turf, including home lawns golf courses and athletic field. The residential lawn uses include spot and broadcast applications.
It is also used i n aquatic settings to control aquatic weeds growing in lakes, ponds, reservoirs, and wetlands, and to control woody brush and herbaceous weeds in wetlands and on the banks and shores of aquatic sites.

According to the most recent scoping document, there are hundreds of products that contain triclopyr, triclopyr salts, and triclopyr esters. HED focused on a subset of these labels that covered a majority of the uses in order to identify relevant use sites and application rates for this

reassessment. Tabl e 3.3.2 summarizes the scenarios and rates assessed.Triclopyr Human Health Risk Assessment DP# D426071

Page 11 of 37 Table 3.3.2. Summary of Relevant Residential Use Patterns for Reevaluation.

Chemical

Name Registration
Number and
Product Name Use Site Formulation
and Percent
Active Ingredient Application
method Maximum App Rate

Triclopyr triethylamine salt (116002) 62719

- 226 Dow AgroSciences
Brush & Weed

Herbicide For the control of woody plants, vines
and broadleaf weeds around homes, cabins, fences, walkways and
other non

- crop areas. This product is for
outdoor residential use only. Soluble Liquid (SL)
8.8% Ground, hose

- end

sprayer, tank

- type sprayer, backpack

sprayer 9 lb ae/A

0.0375 lb ae/gal

0.0096 lb ae/ ft 2

Triclopyr, butoxyethyl

ester (116004) 62719

- 566 Turflon
Ester Ultra Golf course turf,
ornamental lawn and
turf EC 60.5% Ground (sprayer) 1.5 lb a e /A

Triclopyr triethylamine salt (116002) 62719

- 187
Renovate * Aquatic areas/water SL 44.4 % Spray boom, handgun, or other
suitable equipment
mounted on a boat or vehicle,

helicopter. 6 lb ae/A

(equivalent to 0.552 mg/L water concentration)



### 3.4 Anticipated Exposure Pathways

RD has requested an assessment of human health risk to support the 1) petition to amend the tolerance expressions for triclopyr to include a new form ulation, triclopyr choline salt (PP# 4F8279); and 2) petition to remove the grazing restriction for lactating dairy cattle, and establish
a 0.7 0

- ppm tolerance for residues in milk, fat and an increased tolerance of 0.03 ppm for residues in milk (PP# 4F8249 ). Humans may be exposed to triclopyr in food and drinking water, since triclopyr may be applied directly to growing crops and water, and application may result in triclopyr reaching surface and ground water sources of drinking water. There are currently registered residential uses of triclopyr, so there is likely to be exposure in residential or non

occupational settings. The proposed action to remove a grazing restriction for dairy cattle is not expected to result in additional occupational exposures; and the proposed registration of the choline salt is covered by the previous actions. No new occupational assessments have been
conducted.

3.5 Consideration of 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 Lo w

- Income Populations," http://www.archives.gov/federal

- register/executive

- orders/pdf/12898.pdf . As a part of every pesticide risk assessment, OPP considers a large var iety 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. Extensive data on food consumption patterns are compiled by the U.S. Department of Agriculture (USDA) under the National Health and Nutrition Examination Survey, What We Eat
in Ameri ca, (NHANES/WWEIA) and are used in pesticide risk assessments for all registered food uses of a pesticide. These data are analyzed and categorized by subgroups based on age,Triclopyr Human Health Risk Assessment DP# D426071

Page 12 of 37 

### season of the year, ethnic group, and region of the country. Additionally, OPP i s able to assess dietary exposure to smaller, specialized subgroups and exposure assessments are performed when conditions or circumstances warrant. Whenever appropriate, non

- dietary exposures based on home use of pesticide products and associated risks f or adult applicators and for toddlers, youths, and adults entering or playing on treated areas post

- application are evaluated. Further considerations are currently in development as OPP has committed resources and expertise to the development of specializ ed 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 and Dose

- Response Assessment

The bioequivalency of the three chemical forms of triclopyr (acid, triethylamine salt, and butoxyethyl ester) has been addressed through a variety of special studies with the salt and ester forms, including data on comparative disposition, plasma half

- life, tissue distribution, and hydrolytic cl eavage. These studies were found to adequately address the issue of bioequivalency. Therefore, studies conducted with any one form of triclopyr have been used to support the toxicology database as a whole.

No new toxicity and/or metabolism data have b een received since the last risk assessment. This
assessment includes summaries of prior assessments.

4.1 Toxicology Studies Available for Analysis

The toxicological database for triclopyr is adequate for hazard characterization, toxicity endpoint selection, and FQPA SF evaluation. Since the most recent risk assessment for triclopyr, acceptable subchronic neurotoxicity (MRID 49306303) and immunotoxic ity (MRID 49433001) studies have been submitted and show no evidence of neurotoxicity or immunotoxicity, respectively. Waivers have also been submitted by the registrant for the ACN and subchronic
inhalation studies. The HED HASPOC discussed the need for these studies using a WOE approach (J. Leshin; TXR# 0057009). HASPOC concluded that the ACN is not required at this time. The subchronic inhalation study is required at this time and an additional 10X UF DB 

### will be applied for lack of the study when asse ssing inhalation exposure scenarios.

4.2 Absorption, Distribution, Metabolism, & Elimination (ADME)

In a rat metabolism study with 14 

### C

- triclopyr acid, absorption, distribution, metabolism, and excretion was assessed following single oral doses of 3 mg/ kg or 60 mg/kg, repeated doses of 3 mg/kg, and an intravenous dose at 3 mg/kg. Regardless of dose level or route of administration, triclopyr was well absorbed with peak plasma levels reached within 3

- 4 hours. Radioactivity in
the tissues at 72 hours was minimal (<0.54%). At the low dose, >90% of the radioactivity was excreted within 24 hours primarily via the urine. The high dose yielded similar overall results except that urinary elimination was decreased between 0

- 12 hours due to saturation of renal
excretion mechanisms. Un

- metabolized parent represented >90% of the urinary radioactivity.Triclopyr Human Health Risk Assessment DP# D426071

Page 13 of 37 

### 4.2.1 Dermal Absorption

Dermal absorption studies in rabbits and humans are available for triclopyr. In both studies, absorption was estimated at approximately 2%. There was no dermal hazard identified in the toxicological database for triclopyr. As a result, a dermal

- absorption factor is not needed because a quantitative dermal assessment was not performed

4.3 Toxicological Effects

Overall, eff ects in the triclopyr database were indicative of kidney and liver toxicity in rats and dogs, respectively. The primary effect observed in rats was degeneration of the proximal tubule, which was seen at approximately the same dose (20

- 28 mg/kg/day) in the subchronic oral and

two

- generation reproduction toxicity studies. Body

- weight decrements were also noted in rats in the subchronic neurotoxicity and immunotoxicity studies at much higher doses (200

- 250 mg/kg/day). In dogs, liver toxicity was evidenced b y increased liver enzymes, increase liver weights, and liver histopathology at a similar dose as rat effects (20 mg/kg/day). Changes in hematological parameters (decreased packed

- cell volume, decreased hemoglobin, and decreased red blood cell count) were also observed in dogs at the same dose.

Offspring and developmental effects occurred in the presence of maternal and parental toxicity.
In the two

- generation reproduction study with triclopyr acid, rare malformations, including exencephaly (brain protr udes outside of the skull) and ablepharia (absence of eyelids), were seen in rat pups at the mid

- and high

- doses (25 mg/kg/day and 250 mg/kg/day, respectively). These malformations were considered using a WOE approach to be evidence of qualitative increas ed susceptibility by the Hazard Identification Assessment Review Committee (HIARC) Developmental/Reproductive Toxicity Peer Review. A concern for qualitative susceptibility also exists in the rat developmental toxicity study with triclopyr acid although t he evidence was not as conclusive as in the rat reproduction

- toxicity study. Cleft palate, brachycephaly (flat head syndrome), and delayed ossification occurred at the highest dose tested (200 mg/kg/day) while the NOAEL for maternal toxicity was not estab lished since clinical signs of severe toxicity due to the bolus administration of a low pH compound were seen at the lowest dose tested (50 mg/kg/day). There were no other concerns for susceptibility identified in the other developmental studies where dev elopmental and maternal effects were seen at 100 mg/kg/day and 300 mg/kg/day in the rabbit and rat, respectively.

Triclopyr has been classified has having low acute toxicity via the oral, dermal and inhalation routes (Toxicity Category III

- IV). The salt form was found to be corrosive to the eye, while the ester form was only minimally irritating. Both the salt and ester forms of triclopyr were found to be dermal sensitizers, but not a dermal irritant.

4.4 Safety F actor for Infants and Children (FQPA S afety Factor)

The RAB1 risk assessment team recommends that the FQPA SF be reduced to 1X for all exposure scenarios except inhalation based on the following considerations outlined in more detail in the sections below: (1) the toxicology database for tri clopyr is adequate for FQPA SF consideration; (2) there is no evidence of neurotoxicity from triclopyr exposure; (3) selected endpoints are protective of any observed pre

- or post

- natal offspring susceptibility; and (4) the exposure databases are sufficien t and unlikely to underestimate exposure.Triclopyr Human Health Risk Assessment DP# D426071

Page 14 of 37 

### For inhalation exposures, the FQPA SF has been retained at 10X to incorporate the UF DB 

### for lack of a subchronic inhalation study.

4.4 .1 Completeness of the Toxicology Database

The existing toxicological database is adequate for characterizing triclopyr toxicity and quantification of hazard for dietary and occupational exposures. The developmental toxicity
studies in rats and rabbits and two

- generation reproduction toxicity studies in rats are available to

assess potential fetal/offspring sensitivity. The 10X FQPA SF has been retained for inhalation exposures due to lack of a subchronic inhalation study.

4.4.2 Evidence of Neurotoxicity

There is no evidence of neurotoxicity in the triclopyr toxicological database.

4.4.3 Evidence of Sensitivity/Susceptibility in the Developing or Young Animal

There is evidence of increased qualitative susceptibility to offspring from triclopyr exposure in
the two

- generation reproduction toxicity study and potential qualitative susceptibility in the rat developmental toxicity study (see Section 4.3). Concern is low since effects are well

characterized with clearly established NOAEL/LOAEL values, effects were seen in the presence of parental toxicity, and selected endpoints are protective of the observed effects.

4.4.4 Residual Uncertainty in the Exposure Data base

There are no residual uncertainties with respect to exposure data. The dietary food exposure
assessment utilizes tolerance

- level residues (established or recommended) and 100% CT for all proposed/established commodities. By using these assumptions, the acute and chronic exposures/risks will not be underestimated. The dietary drinking water assessment utilizes water concentration values generated by models and associated modeling parameters that are designed to provide conservative, health

- protectiv e, high

- end estimates of water concentrations that will not likely be exceeded. The residential handler and post

- application exposure assessments are based upon the residential SOPs in conjunction with PHED unit exposures. The residential
SOPs are based upon reasonable worst

- case assumptions and are not expected to underestimate risk. These assessments of exposure are not likely to underestimate the resulting estimates of risk from exposure to triclopyr.

4.5 Toxicity Endpoint and Point of Departure Sele ctions

Toxicity endpoints and PODs for triclopyr have not changed since the last risk assessment (W. Donovan; 24

- JUL

- 2002; D263770)

, except one endpoint was selected to assess short

- and
intermediate

- term durations for the dermal and inhalation exposure scenarios. Endpoints for long

- term dermal and inhalation exposures are not needed because long

- term exposures are not expected based on the use pattern for triclopyr. Additionally, no dermal hazard was identified; therefore, a dermal endpoint was not selected.Triclopyr Human Health Risk Assessment DP# D426071

Page 15 of 37 

### 4.5.1 Dose

- Response Assessment

Acute Dietary Endpoint (general population including infants and children) : The acute refer ence dose (aRfD) for the general population, including infants and children, was established using the NOAEL of 100 mg/kg/day from the developmental rat toxicity study (with the ester form). The LOAEL of 300 mg/kg/day is based on mortality in maternal ani mals observed earlier in the study; therefore, the deaths were considered attributable to a single dose. Other effects seen at this dose included clinical signs, necropsy findings, decreased food and water consumption, and increased kidney and liver weigh ts. Deaths and abortions observed in the developmental rabbit studies were not considered to be attributable to a single dose because they occurred later in the studies after repeated dosing. The aPAD of 1.0 mg/kg/day is based on the NOAEL of 100 mg/kg/d ay and a 100

- fold uncertainty factor (10X for interspecies extrapolation, 10X for intraspecies extrapolation, and 1X for FQPA SF).

Acute Dietary Endpoint ( females 13

- 49 years old): The aRfD for females 13

- 49 years old was established using the NOAEL of 5 mg/kg/day from the two

- generation reproduction toxicity study in rats. The LOAEL of 25 mg/kg/day was based on an increased incidence of rare malformations (exencephaly and ablepharia), which are considered single dose effects. The aPAD of 0.05 mg/kg/day for females 13

- 49 years old is based on the NOAEL of 5 mg/kg/day
and a 100

- fold uncertainty factor (10X for interspecies extrapolation, 10X for intraspecies extrapolation, and 1X for FQPA SF).

Chronic Dietary Endpoint (all populations) : Chronic dietary exposures were assessed using the

two

- generation reproduction toxicity study with a parental NOAEL of 5 mg/kg/day. The parental LOAEL of 25 mg/kg/day is based on degeneration of the proximal renal tubules. Offspring effects were seen at the same dose as parental toxicity. The study and endpoint are appropriate for the route and duration of exposure. It is protective of adverse effects seen in rats, mice, and dogs after chronic repeated exposures to triclopyr. The cPAD of 0.05 mg/kg/day is
based on the NOAEL of 5 mg/kg/day and a 100

- fold uncertainty factor (10X for interspecies extrapolation, 10X for intraspecies extrapolation, and 1X for FQPA SF).

Incidental Oral Exposure (short

- and intermediate

- term) : The subchronic oral toxicity study in
rats with the acid form was selected for evaluating incidental oral exposures with a NOAEL of 5 mg/kg/day. The LOAEL of 20 mg/kg/day is based on degeneration of the proximal renal
tubules. The two

- generation reproduction study is supportive of this endpoint with s imilar NOAEL and LOAEL values of 5 and 25 mg/kg/day, respectively. This endpoint is protective of adverse effects seen in rats, mice, and dogs after subchronic repeated exposures to triclopyr. The LOC for incidental oral exposures is 100 (10X for intersp ecies extrapolation, 10X for intraspecies extrapolation, and 1X for FQPA SF).

Dermal Endpoints (all durations) : A dermal endpoint was not selected. Since there is no concern for increased quantitative sensitivity/susceptibility to offspring from triclop yr exposure, the effects of concern in adults and offspring are adequately assessed in the dermal toxicity study where no adverse dermal or systemic effects were observed up to the limit dose (1000 mg/kg/day).

Inhalation Endpoints (short

- and intermediate

- term) : The subchronic oral toxicity study in rats with the acid form was selected for evaluating inhalation exposures with a NOAEL of 5 mg/kg/day. The LOAEL of 20 mg/kg/day is based on degeneration of the proximal renalTriclopyr Human Health Risk Assessment DP# D426071

Page 16 of 37 

### tubules. The two

- gen eration reproduction study is supportive of this endpoint with similar NOAEL and LOAEL values of 5 and 25 mg/kg/day, respectively. This endpoint is protective of adverse effects seen in rats, mice, and dogs after subchronic repeated exposures to triclopyr

. Inhalation exposure is assumed to be equivalent to oral exposures. Due to lack of a subchronic inhalation study, the FQPA SF incorporates a UF DB 

### of 10X. As a result, the LOC for inhalation exposures is 1000 (10X for interspecies extrapolation, 10X for intraspecies extrapolation, and 10X for FQPA SF/UF DB 

### ).

4.5.2 Recommendation for Combining Routes of Exposures for Risk Assessment

When there are potential occupational and residential exposures to a pesticide, the risk assessment must address exposures from three major sources (oral, dermal, and inhalation) and determine whether the individual exposures can be combined if they have the same toxicological
effects. For short

- and intermediate

- exposures, incidental oral and inhalation exposures can be
comb ined for triclopyr since the same study and effects were chosen for both routes. No dermal endpoint was selected.

4.5.3 Cancer Classification and Risk Assessment Recommendation

A cancer risk assessment is not required. The Agency classified triclopyr a s a “Group D
Chemical

– unable to be classified as to human carcinogenicity.” This is based on marginal evidence of mammary tumors in female rats and mice and benign adrenal pheochromocytomas in male rats. There was no evidence of mutagenicity in a full battery of studies for triclopyr.

4. 5

. 4 Summary of Points of Departure and Toxicity Endpoints Used in Human Risk
Assessment

Table 4.5.4.1. Summary of Toxicological Doses and Endpoints for Triclopyr for Use in Dietary and Non

Occupational Human Health Risk Assessments

.

Exposure/Scenario POD Uncertainty/FQPA Safety Factors RfD, PAD, LOC for
Risk Assessment Study and Toxicological Effects

Acute Dietary (General Population including infants and children) NOAEL = 100 mg/kg/day UF A = 10X
UF H = 10X FQPA = 1X aRfD = 1.0 mg/kg/day

aPAD = 1.0 mg/kg/day Developmental Rat Toxicity Study
with ester form Maternal LOAEL = 300 mg/kg/day based on mortality. Additional
effects seen at this dose included clinical signs, necropsy findings,
decreased food and water

con sumption, and increased kidney and liver weights.

Acute Dietary (Females 13

- 49 years old) NOAEL = 5 mg/kg/day UF A = 10X
UF H = 10X FQPA = 1X aRfD = 0.05 mg/kg/day

aPAD = 0.05 mg/kg/day Two

- Generation Rat Reproduction Study with acid form LOAEL = 25 mg/kg/day based on
increased incidence of rare malformations (exencephaly and ablepharia)

.

Chronic Dietary (All Populations) NOAEL = 5 mg/kg/day UF A = 10X
UF H = 10X FQPA = 1X cRfD = 0.05 mg/kg/day

cPAD = 0.05 mg/kg/day Two

- Generation Rat Reproduction Study with acid form LOAEL = 25 mg/kg/day based on degeneration of the proximal renal
tubules

.Triclopyr Human Health Risk Assessment DP# D426071

Page 17 of 37 Table 4.5.4.1. Summary of Toxicological Doses and Endpoints for Triclopyr for Use in Dietary and Non

Occupational Human Health Risk Assessments

.

Exposure/Scenario POD Uncertainty/FQPA Safety Factors RfD, PAD, LOC for
Risk Assessment Study and Toxicological Effects

Incidental Oral
Short

- Term (1

- 30 days) and
Intermediate

- Term (1

- 6 months) NOAEL = 5 mg/kg/day UF A = 10X
UF H = 10X FQPA = 1X Residential LOC for
MOE = 100 Subchronic Oral Rat Toxicity Study
with acid form LOAEL = 20 mg/kg/day based on degeneration of the proximal renal
tubules

. Dermal
Short

- Term (all durations) No hazard was identified for dermal exposure; therefore a quantitative dermal assessment is not needed.

Inhalation
Short

- Term (1

- 30 days) and
Intermediate

- Term (1

- 6 months) NOAEL = 5 mg/kg/day

Inhalation assumed equivalent to oral UF A = 10X
UF H = 10X FQPA/UF DB = 10X Residential LOC for
MOE = 1000 Subchronic Ora l Rat Toxicity Study
with acid form LOAEL = 20 mg/kg/day based on degeneration of the proximal renal
tubules

. Cancer (oral, dermal, inhalation) Classified as a “ Group D Chemical

– unable to be classified as to human carcinogenicity

. ”

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

- effec t level.
LOAEL = lowest

- observed adverse

- effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human population (intraspecies). UF DB = database uncertainty factor. FQPA SF = FQPA Safety Factor. PAD = population

- adjusted dose (a = acute, c = chronic). RfD = reference dose (a = acute, c = chronic). MOE = margin of exposure. LOC = level of concern.

Table 4.5.4.2. Summary of Toxicological Doses and Endpoints for Triclopyr for Use in Occupational Human
Health Risk Assessments

. Exposure/Scenario POD Uncertainty
Factors LOC for Risk
Assessment Study and Toxicological Effects

Dermal
Short

- Term (all durations) No hazard was identified for dermal exposure; therefore a quantitative dermal assessment is not needed.

Inhalation
Short

- Term (1

- 30 days) and
Intermediate

- Term (1

- 6 months) NOAEL = 5 mg/kg/day

Inhalation assumed equivalent to oral UF A = 10X
UF H = 10X
UF DB = 10X Occupational LOC for
MOE = 1000 Subchronic Oral Rat Toxicity Study
with acid form LOAEL = 20 mg/kg/day based on degeneration of the proximal renal
tubules

. Cancer (oral, dermal, inhalation) Classified as a “ Group D Chemical

– unable to be classified as to human carcinogenicity

. ”

Point of d eparture (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. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human po pulation (intraspecies). UF L = use of a LOAEL to extrapolate a NOAEL. UF DB = database uncertainty factor. MOE = margin of exposure. LOC = level of concern.



### 5.0 Dietary Exposure and Risk Assessment

The residue chemistry data submitted in support of proposed uses were evaluated by HED on 04

- FEB

- 2016 (Memo, J. Tyler; D419487 ). The drinking water assessment was completed by EFED
on 17

- JUN

- 2002 (Memo, M. Mahoney; D283715) and 0 4

- JUN

- 2015 (Memo, L. Liu; D419489)

. The dietary exposure assessment was completed in a HED memorandum dated 04

- FEB

- 2016 (Memo, J. Tyler; D426072 ).Triclopyr Human Health Risk Assessment DP# D426071

Page 18 of 37 

### 5.1 Residues of Concern Summary and Rationale

The qualitative nature of the residue in rice, grass, fish, shellfish, and livestock is adequately
understood based on the available metabolism studies. The residues of concern are as follows (Memos, W. Smith, 15

- JUL

- 1996; W. Donovan, 27

- APR

- 2001, D274243): triclopyr per se in grass, rice, milk, poultry, and eggs; triclopyr and TCP in m eat, meat byproducts and drinking water; and triclopyr, TCP, and 2

- methoxy

- 3,5,6

- trichloropyridine (TMP) in fish and shellfish. It should be noted that §180.417(a)(1) lists the tolerance expression for fish and shellfish as triclopyr per se

. 40 CFR §180. 417 should be updated to include the recommended tolerance expression for fish and shellfish. TCP is part of the tolerance expression for triclopyr for meat and meat byproducts; therefore, it has been included in the dietary exposure assessment for this

a ction. Risk assessme nt and characterization of TCP derived from multiple chemicals h ave been assessed in a separate document (Memo, W. Donovan et al. , 06

- JUN

- 2002, D283101 ).

5 .2 Food Residue Profile

PP# 4F8279 : Dow AgroSciences has submitted a petition to amend tolerance expressions for triclopyr to include a new formulation, triclopyr choline salt. The company proposes that the tolerance expression in 40 CFR §180.417(a) be updated to state:

40 CFR 180.417(a)(1): “Tolerances are established fo r residues of the herbicide triclopyr (2

- [(3,5,6

- trichloro

- 2

- pyridinyl)oxy]acetic acid), including its metabolites and degradates, in or on the commodities in the table below resulting from the application of the butoxyethyl ester of triclopyr, triethylami ne salt of triclopyr, or triclopyr choline. Compliance with the tolerance levels specified below is to be determined by measuring only triclopyr.

and,

40 CFR 180.417(a)(2): Tolerances are established for residues of the herbicide triclopyr (2

- [(3,5,6

- tri chloro

- 2

- pyridinyl)oxy]acetic acid), including its metabolites and degradates, in or on the commodities in the table below resulting from the application of the butoxyethyl ester of triclopyr, triethylamine salt of triclopyr, or triclopyr choline. Complian ce with the tolerance levels specified below is to be determined by measuring the combined residues of triclopyr and its metabolite 3,5,6

- trichloro

- 2

- pyridinol (TCP).”

In a memo dated 22

- MAR

- 2012, HED reviewed a request to determine the bioequivalence
bet ween triclopyr and triclopyr choline salt, and agreed that bioequivalence was supported by the currently available information (Memo, G. Kramer, D399410). Therefore, HED recommends in favor of the request to amend the tolerance expressions for triclopyr t o include triclopyr choline
salt.

PP# 4F8249 : Dow AgroSciences has submitted a petition to remove the grazing restriction for lactating dairy cattle on several r egistered labels for triclopyr

. In addition, the company has also proposed the establishment of a tolerance for residues in milk, fat (0.70 ppm) as well as increased tolerances for residues in milk (0.60 ppm), meat (0.08 ppm), fat (0.09 ppm), and meat byproducts (0.7 0 ppm). The ruminant feed items associated with triclopyr are grass forage and
h ay, and rice grain. Using residues from previously submitted magnitude of the res idu e studies on grass and rice, and residues from the newly submitted dairy cattle feeding study (MRID#Triclopyr Human Health Risk Assessment DP# D426071

Page 19 of 37 

### 49741900 1 )

, HED recalculated the maximum reasonable dietary burden (MRDB) for dairy cattl e to include these commodities, and determined that the following tolerances should be established for residues of triclopyr in/on milk and livestock commodities :

40 CFR §180.417 (a)(1)
Milk 0.60 ppm 40 CFR §180.417 (a)(2)
Meat* 0.10 ppm Fat* 0.10 ppm Meat byproducts* 0.50 ppm * of cattle, goat, hog, horse, and sheep.



### A revised Section F should be submitted to include these tolerances.

5.3 Water Residue Profile

A r evised drinking water assessment was not required since the proposed uses will not have an effect on the concentration of triclopyr in drinking water

. Based on the greatest exposure scenario resulting from direct aquatic application of triclopyr to surface water, the EDWCs of triclopyr for surface water are estimated to be 1,049 ppb for acute (peak) exposures and 390 ppb for chronic (annual average) expo sures. EPA calculated and required setback distances from the application site to the functional potable water intake in order to maintain average drinking water concentration levels below 400 ppb. Furthermore, since potable water intakes are required to be turned off until triclopyr concentration levels are below 400 ppb, EPA has determined that for acute and chronic dietary risk assessments, the water concentration value of 400 ppb is appropriate to use to assess the contribution to drinking water.

It should be noted that EDWCs were not incorporated directly in the 2002 dietary exposure assessment, but HED calculated drinking water levels of comparison ( DWLOC s ), which is a theoretical upper limit on a pesticide’s concentration in drinking water in light of total aggregate exposure to a pesticide in food, drinking water, and through residential uses. In this assessment, the EDWC of 400 ppb was incorporated directly in the acute and chronic dietary exposure

assessments.

5.4 Dietary Risk Assessment

Unref ined acute and chronic aggregate dietary (food and drinking water) exposure and risk assessments were conducted using DEEM

- FCID Version 3.16. This software uses 2003

- 2008 food consumption data from USDA’s NHANES/WWEIA

.

5.4.1 Description of Residue and Pe rcent Crop Treated Data Used in Dietary Assessment

The acute dietary exposure assessment was unrefined, using tolerance

- level residues and assuming 100% CT for all registered and proposed commodities. The chronic dietary exposure assessment was slightly refined, using tolerance

- level residues for all commodities except milk and assuming 100% CT for all registered and proposed commodities. An AR calculated from a recently submitted livestock feeding study was used for milk. DEEM Version 7.81 default

proc essing factors were used to estimate residues in processed commodities. Drinking water was incorporated directly into the dietary assessment

.Triclopyr Human Health Risk Assessment DP# D426071

Page 20 of 37 

### 5.4.2 Acute Dietary Risk Assessment

For females 13

- 49 years old, the resulting acute (food and drinking water) risk estimate at the
95 th 

### percentile of the exposure distributio n is 53 % of the aPAD. For the general U.S. population and all other population subgroups, the resulting acute food and drinking water risk estimates are
not of concern to HED (< 100% aPAD) at the 95 th 

### percentile of the exposure distribution. The most highly exposed population subgroup i s all infants (<1 year old) at 8 % of the aPAD.

It should be noted that females 13

- 49 years old have a lower aPAD (0.05 m g /kg/day) than the general U.S. populat ion and all other population subgroups (1.0 mg/kg/day). As a result, even though the exposure estimate for females 13

- 49 years old was lower than the estimate for the general U.S. population, females 13

- 49 years old have the highest risk estimate.

5.4.3 Chronic Dietary Risk Assessment

The resulting chronic (food and drinking water) risk estimates are not of concern to HED (<100% cPAD) for general U.S. population and all population subgroups. The most highly exposed population subgroup is all infants (< 1 year old) at 46 % of the cPAD.

5.4.4 Cancer Dietary Risk Assessment

A cancer dietary assessment was not conducted because triclopyr is classified as a “Group D
Chemical

– unable to be classified as to human carcinogenicity.”

5. 4.5 Summary Table

Table 5.4.5. Summary of Dietary Exposure and Risk for Triclopyr.*

Population Subgroup Acute Dietary (Food and Drinking Water) (95 th Percentile) Chronic Dietary (Food and Drinking Water) Dietary Exposure (mg/kg/day) % aPAD Dietary Exposure (mg/kg/day) % aPAD

General U.S. Population 0.033198 3.3 0.010008 20
All Infants (<1 year old) 0.080077 8.0 0.023278 46

Children 1

- 2 years old 0.075543 7.6 0.017810 36

Children 3

- 5 years old 0.050707 5.1 0.013791 28

Children 6

- 12 years old 0.034563 3.5 0.009612 19

Youth 13

- 19 years old 0.025114 2.5 0.007325 15

Adults 20

- 49 years old 0.026457 2.6 0.009698 19

Adults 50

- 99 years old 0.024208 2.4 0.009580 19

Females 13

- 49 years old 0.026561 53 0.009493 19
*Population subgroup with the highest exposure and risk is in bold type. The aPAD for females 13

- 49 years of age is 0.05 mg/kg/day; aPAD for general U.S. population and all other population subgroups is 1.0 mg/kg/day. The cPAD for general U.S. population and all po pulation subgroups is 0.05 mg/kg/day.



### Risk assessment and characterization of TCP derived from multiple chemicals have been assessed in a separate document (Memo, W. Donovan et al

. , 06

- JUN

- 2002, D283101). Since TCP is part of the tolerance expression for triclopyr for meat and meat byproducts , it has been included in the dietary exposure assessment for this action. The conclusions of the 2002 TCP assessment that acute and chronic dietary aggregate exposure estimates are below HED’s LOC
are still considered valid.Triclopyr Human Health Risk Assessment DP# D426071

Page 21 of 37 

### 6.0 Residential (Non

- Occupat ional) Exposure/Risk Characterization

The residential exposure assessment was completed in a HED memorandum dated 04

- AUG

2015 (Memo, L. Venkateshwara; D426070 ).

The proposed uses do not involve applications by homeowners or commercial applicators in residential settings. Therefore, no new residential exposure is expected. However, there are existing residential uses that have been reassessed in this document to reflect updates to HED’s 2012 Residential SOPs ( http://www2.epa.gov/pesticide

- science

- and

- assessing

- pesticide

risks/stan dard

- operating

- procedures

- residential

- pesticide ) along with policy change s for body

weight assumptions.

Based on the registered residential uses (turf and aquatic use ; see Table 3.3.2 ), handler inhalation and post

- application inhalation and ingestion exposures are expected for adults; post

- application inhalation and ingestion exposure are expected for children (3 to <6 years old); and post

application incidental oral exposures are expe cted for children (1 to <2 years old). The dermal route of exposure is not quantitatively assessed because there is no dermal hazard. Short

- term exposures are anticipated for residential handlers, while short

- and intermediate

- term residential post

- appli cation exposures are expected. Short

- term risk estimates are protective of
intermediate

- term because the POD is the same.

6.1 Residential Handler Exposure

Residential handler assessments were only conducted for the turf uses, and not the aquatic use
sites b ecause the aquatic sites are not residential in nature and homeowner applications are unlikely. It is noted that the aquatic label includes the following statements which imply commercial/professional applications: (1) state and/or local authorities are to be consulted prior to applying this product to public waters; and (2) state or local public agencies may require permits. The results of the residential handler exposure and risk assessment indicate that short

term inhalation risks do not exceed HED’s LOC (i.e. an MOE < 1000) for all turf scenarios

.

Table 6

. 1 . Residential Handler Exposure and Risk for T riclopyr, Triclopyr TEA, and Triclopyr BEE.

Exposure Scenario App. Rate 1 Amount
Handled 2 Unit Exposure (mg/lb ai) 2 Dose (mg/kg/day) 4 MOE 5 (LOC = 1000)

Baseline
Inhalatio n 3 Baseline
Inhalation Baseline
Inhalation

Mixing/Loading/Applicator

– Turf

Mixing/Loading/Applying Liquids with Hose End Sprayer 9 lb ae/acre 0.5 acres 0.022 0.0012 4,000

Mixing/Loading/Applying Liquids with Manually Pressurized H andwand 0.0375 lb ae/gal 5 gallons 0.018 0.000042 120,000

Mixing/Loading/Applying Liquids with Sprinkler Can 0.0096 lb
ae/ ft 2 1000
ft 2 0.022 0.0026 1,900

Mixing/Loading/Applying Liquids
with Backpack 0.0375 lb ae/gal 5 gallons 0.14 0.00033 15,000

1. Application rate based on label Dow AgroSciences Brush &Weed Herbicide (Reg. No. 62719

- 226).
2. U nit exposure values and estimates for area treated or amount handled based on Exposure Science Advisory Council 2012
Residential SOPs: http://www2.epa.gov/pesticide

- science

- and

- assessing

- pesticide

- risks/standard

- operating

- procedures

residential

- pesticide

. 3. Baseline Inhalation: no respirator.Triclopyr Human Health Risk Assessment DP# D426071

Page 22 of 37 4. Inhalation Dose (mg/kg/day) = daily unit exposure (mg/lb ai) * application rate (lb ai/unit volume or area) * amount handled (unit volume or area) * inhalation absorption (100%) / body weight (80 kg).
5. MOE = NOAEL (short

- term inhalation = 5 mg/kg/day) / daily dose (mg/kg/day). LOC = 1000.



### 6.2 Post

- Application Exposure

Table 6.2.1 presents the post

- application incidental oral MOE values calculated for the broadcast liquid application of triclopyr, triclopyr TEA, and triclopyr BEE to turf. The post

- application
MOEs for hand

- to

- mouth, object

- to

- mouth

, and soil ingestion are not of concern to HED (MOEs range from 220 to 98,000).

Table 6.2.1

. Residential Post

- application Non

- cancer Exposure and Risk Estimates for Tric lopyr, Triclopyr TEA, and Triclopyr BEE.

Lifestage Post

- application Exposure Scenario Application
Rate 1 Dose (mg/kg/day) 2 MOEs 3 (LOC = 100) Use Site Route of Exposure

Child (1 to <2 years old) Liquid Application to
Turf ST Hand

- to

- Mouth
1.5 lb ae/A 0.0228 220 ST Object

- to

- mouth 0.00069 7,200 ST/IT Soil Ingestion 5.1E

- 04 98,000

1. Based on label Dow AgroSciences Turflon Amine (Reg. No. 62719

- 257).
2. Dose (mg/kg/day) equations (see Appendix B)
3. MOE = NOAEL ÷ Daily Dose (mg/kg/day). ST/IT Incidental Oral and Inhalation NOAEL = 5 mg/kg/day. LOC = 100.



### Tables 6.2.2 and 6.2.3 provide the post

- application inhalation and ingestion risk estimates for exposure of swimmers to triclopyr.

Table 6.2.2 . Short

- Term Post

- application Exposure

- Inhalation of Water by Swimmers.

Exposure Scenario Cw 1 (mg/L) IR 2 (L/hr) ET 3 (hr/day) BW 4 (kg) Exposure 5 Absorbed Dose 6 (mg/kg/day) MOE 7 (LOC =

1000) Swimmer; adult 0.552 0.64 0.025 80 9.1E

- 05 1.14E

- 06 4,400,000 Swimmer; child (3 to <6 years old) 0.42 0.076 19 1.8E

- 04 9.55E

- 06 520,000

1. Cw = concentration in water is based on the application rate provided on the product label. An assumption of 4 feet depth (a nd uniform distribution) was used to estimate the concentration in water.
2. IR = inhalation of water; based on the Risk Assessment Guidance for Superfund (RAGS) Part A ( http://www.epa.gov/risk/risk

assessment

- guidance

- superfund

- rags

- part ) which references a value fr om the Superfund Exposure Assessment Manual (USEPA, 1988). The recommended point estimate for use in post

- application incidental ingestion exposure assessments is 0.05 L/hr of swimming for adults and children 3 to <6 years old.
3. ET = exposure time; based o n 2011 Exposure Factors Handbook (Table 16

- 20)

. 4. BW = body weight; based on the Residential Pesticide Exposure Assessment SOP (February

- 2012).
5. Exposure = ( VV pp * IR * ET )

. 6. Absorbed Inhalation dose = (E x AF) ÷ BW

. 7. MOE = NOAEL (5 mg/kg/day; adult and chil d) ÷ dose (mg/kg/day)

.

Table 6.2.3 . Short

- Term Post

- application Exposure

- Ingestion of Water by Swimmers.

Exposure Scenario Cw 1 (mg/L) IgR 2 (L/hr) ET 3 (hr/day) BW 4 (kg) Oral Dose 5 (mg/kg/day) MOE 6 (LOC = 100) Swimmer; adult 0.552 0.05 0.025 80 0.000008625 580,000 Swimmer; child (3 to <6 years old) 0.05 0.076 19 0.0001104 45,000

1. Cw = concentration in water is based on the application rate provided on the product label. An assumption of 4 feet depth (and uniform distribution) was used to estimate the concentration in water.
2. IgR = ingestion rate of water; based on the RAGS Part A ( http://www.epa.gov/risk/risk

- assessment

- guidance

- superfund

- rags

- part ) which references a value from the Superfund Exposure Assessment Manual (USEPA, 1988). The recommended point estimate for use in post

- application incidental ingestion exposure assessment s is 0.05 L/hr of swimming for adults and children 3 to <6 years old.
3. ET = exposure time; based on 2011 Exposure Factors Handbook (Table 16

- 20)

. 4. BW = body weight; based on the Residential Pesticide Exposure Assessment SOP (February

- 2012).
5. Oral dose = ( Cw x IgR x ET) ÷ BW

. 6. MOE = NOAEL (5 mg/kg/day; adult and child) ÷ dose (mg/kg/day)

.Triclopyr Human Health Risk Assessment DP# D426071

Page 23 of 37 

### 6.3 Residential Risk Estimates for Use in Aggregate Assessment

Table s 6 .3 .1 and 6.3.2 reflects the residential risk estimates that are recommended for use in the

aggreg ate assessment for triclopyr.

MOE Approach (Table 6.3.1)

• The recommended residential exposure for use in the short

- term aggregate assessment for children 1 to <2 years old reflects hand

- to

- mouth incidental oral exposure due to applications to turf.

Aggregate Risk Index ( ARI ) Approach (Table 6.3.2)

• The recommended residential exposures for use in the short

- term aggregate assessment for adults reflects handler inhalation exposures from spot a pplications to turf via sprinkler

can

.

• The recommended residential exposure for use in the short

- term aggregate assessment for
ch ildren 3 to <6 years old reflects combined inhalation and ingestion of water by
swimmers

.Triclopyr Human Health Risk Assessment DP# D426071

Page 24 of 37 Table 6 .3. 1. Recommendations for the Residential Exposures for the Triclopyr Aggregate Assessment Using Total MOE Approach

. 1

Lifestage Residential Handler Residential Post

- application Dose (mg/kg/day) 2 MOE 3 Dose (mg/kg/day) 4 MOE 5

Dermal Inhalation Total Dermal Inhalation Total Dermal Inhalation Oral Total Dermal Inhalation Oral Total
Child ( 1 to <2

years old )

– ST Hand

- to

Mouth Exposure Due

to Turf Use N/A

- - 0.0228

- - - 220 220

1. Bolded risk estimates should contribute to the residential exposure portion of the aggregate assessment.
2. Residential Handler Dose = the highest handler dose s for each applicable lifestage of all s cenarios assessed

. Not applicable.
3. Residential Handler MOE = the MOEs associated with the highest doses identified

. Not applicable.
4. Residential Post

- application Dose = the highest post

- application dose for each applicable lifestage of all scenarios assessed (see Tables 6. 2.1 through 6 .2.3). Total = incidental oral.
5. Residential Post

- application MOE = the MOEs associated with the highes t doses identified (see Tables 6.2.1 through 6 .2.3). Total MOE = 1/[(1/Inhalation MOE) + (1/Incidental oral MOE)], where applicable.

Table 6.3. 2. Recommendations for the Residential Exposures for the Triclopyr Aggregate Assessment Using ARI Approach. 1

Lifestage Residential Handler Residential Post

- application
Dermal
MOE Dermal
ARI Inhalation
MOE 2 Inhalation
ARI 2 Dermal
MOE Dermal
ARI Inhalation
MOE 2 Inhalation
ARI 2 Oral
MOE 3 Oral
ARI 3 Total
ARI 4

Adult

– M/L /A Liquids to Turf with Sprinkler Can - - 1,9 00 1.9 N/A 1.9

Child (3 to <6 years old)

– Swimmer Exposure Due to Aquatic Use N/A

- - 520,000 520 45,000 450 240

1. B olded risk estimates should contribute to the residential exposure portion of the aggregate assessment.
2. MOE inhalation residential exposure = [(short

- term inhalation NOAEL)/(high

- end inhalation residential exposure)]. ARI inhalation = [(MOE inhalation residential exposure)/(MOE target)].
Short

- term inhalation NOAEL = 5 mg/kg/day; high

- end inhalation residential handl er exposure for adults = 0.0026 mg/kg/day; high

- end inhalation residential post

- application exposure for children 3 to <6 years old = 0.00000955 mg/kg /day (swimmer). MOE target = 1000.
3. MOE oral residential exposure = [(short

- term oral NOAEL)/(high

- end incidental oral residential exposure)]. ARI oral residential exposure = [(MOE oral residential exposure)/(MOE target)].
Short

- term oral NOAEL = 5 mg/kg /day; high

- end incidental oral residential exposure for children 3 to <6 years old (swimmer) = 0.00001104 mg/kg/day. MOE target = 100.
4. Total ARI = 1/[ (1/ARI oral) + (1/ARI inhalation)].Triclopyr Human Health Risk Assessment DP# D426071

Page 25 of 37 

### 6.4 Residential Bystander Post

- application Inhalation Exposure

Volatilization of pesticides may be a source of post

- application inhalation exposure to individuals nearby pesticide applications. The agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fu ngicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) in December 2009, and received the SAP’s final report on March 2, 2010 ( http://archive.epa.gov /scipoly/sap/meetings/web/pdf/120309meetingminutes.pdf ). The agency has evaluated the SAP report and has developed a Volatilization Screening Tool and a subsequent Volatilization Screening Analysis ( http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

- OPP

- 2014

- 0219 ). During Registration Review, the agency will utilize this analysis to determine if data (i.e., flux studies, route

- specific inhalation toxicological studies) or f urther analysis is required for triclopyr.

6.5 Spray Drift

Spray drift is a potential source of exposure to those nearby pesticide applications. This is particularly the case with aerial application, but, to a lesser extent, spray drift can also be a

po tential source of exposure from the ground application methods (e.g., groundboom and airblast) employed for triclopyr. The agency has been working with the Spray Drift Task Force (a task force composed of various registrants which was developed as a resul t of a Data Call

- In issued by EPA), EPA Regional Offices and State Lead Agencies for pesticide regulation and other parties to develop the best spray drift management practices (see the agency’s Spray Drift website for more information). 1 

### The A gency has a lso developed a policy on how to appropriately consider spray drift as a potential source of exposure in risk assessments for pesticides. The potential for spray drift will be quantitatively evaluated for each pesticide during
the Registration Review proc ess which ensures that all uses for that pesticide will be considered concurrently. The approach is outlined in the revised (2012) Standard Operating Procedures For Residential Risk Assessment (SOPs)

- Residential Exposure Assessment Standard Operating

Pr ocedures Addenda 1: Consideration of Spray Drift. This document outlines the quantification
of indirect non

- occupational exposure to drift.

7.0 Aggregate Exposure/Risk Characterization

In accordance with the FQPA, HED must consider and aggregate pesticide exposures and risks from three major sources: food, drinking water, and residential exposures. 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. In the case of triclopyr, a ggregate risk assessments were performed for acute aggregate exposure (food + drinkin g water), short

- term aggregate exposure (food + drinking water + residential exposure), and chronic aggregate exposure (food + drinking water). A cancer aggregate risk assessment was not performed because triclopyr is not carcinogenic. All potential exposure pathways w ere assessed in the aggregate risk assessment.

1 Available: http://www2.epa.gov/reducing

- pesticide

- driftTriclopyr Human Health Risk Assessment DP# D426071

Page 26 of 37 

### 7.1 Acute Aggregate Risk

No acute residential/recreational exposures are expected. In the case of triclopyr, the acute aggregate risk is composed of exposures to triclopyr residues in food and drinking wate r and is equivalent to the acute dietary risk discussed in Section 5.4.2. As shown in Table 5.4.5, for
females 13

- 49 years old, the resulting acute dietary ( food and drinking water ) risk estimates are

not of concern to HED ( < 100% aPAD) at the 95 th 

### percent ile of the exposure distribution ( 53 %)

. For the general U.S. population and all other population subgroups, the resulting acute food and drinking water risk estimates are not of concern to HED (>100% aPAD) at the 95 th 

### percentile of the exposure distributi on. The most highly exposed population subgroup is all infants (<1 year old) at 8 % of the aPAD.

7.2 Short

- and Intermediate

- Term Aggregate Risk

Short

- term (1 to 30 day) and intermediate

- term (1 to 6 months) aggregate risk assessments are necessary for both adults and children since there is potential for both handler exposure and post

application exposure from the r esidential uses of triclopyr

. Although there are intermediate

- term residential exposures, an intermediate

- term aggregate was not quantitatively assessed since (1)
the short

- and intermediate

- term PODs are the same and (2) the short

- term aggregate provides a

worst

- case estimate of residential exposure. For these reasons, the short

- term aggregate is protective of the longer

- term exposures.

For the short

- term aggregate risk assessment, potential residential exposures were combined with food and drinking water exposures. Specifically, the short

- term aggregate assessment for adults combines dietary (food + drinking water) exposures with handler inhal ation exposures resulting from the registered turf use . For children 1 to <2 years old, the short

- term aggregate assessment combines dietary (food + drinking water) exposure with potential post

- application incidental oral

exposure resulting from the registered turf use

. For children 3 to <6 years old, the short

- term aggregate assessment combines dietary (food + drinking water) exposure with potential post

application inhalation and incidental oral swimmer exposure resulting from the registered aquati c

use. See Section 6.3 for more information on the residential risk estimates that are recommended for use in the aggregate assessment for triclopyr

.

For children 1 to <2 years old, the MOE approach was used to estimate short

- term aggregate risk. HED’s LOC is for MOEs less than 100. As the short

- term aggregate MOEs are greater than 100, risk esti mates do not exceed HED’s LOC.

Table 7.2.1. Short

- and Intermediate

- Term Aggregate Risk Calculations Using MOE Approach

.

Population Short

- or Intermediate

- Te rm Scenario

NOAEL ( mg/kg/day ) LOC 1 Max
Allowable Exposure 2 ( mg/kg/day ) Average Food
and Water Exposure ( mg/kg/day ) Residential Exposure ( mg/kg/day ) 3 Total Exposure ( mg/kg/day ) 4 Aggregate MOE (food, water, and residential) 5

Children 1 to <2 years
old 5 100 0.05 0.017 810 0.0228 0.040 610 12 0

1. T he level of concern (target MOE) includes 10X for interspecies extrapolation and 10X for intraspecies variation.
2. Maximum Exposure (mg/kg/day) = NOAEL/LOC.
3. Avg. Dietary Exposure. See Ta ble 5.4.5

. 4. R esidential Exposure = O ral exposure for children ( child 1 to <2 years old

– hand

- to

- mouth exposure due to turf use). See Table 5.3

. 5. Total exposure = Avg. Dietary Exposure + Residential Exposure.
6. Aggregate MOE = NOAEL ÷ Total Exposure.Triclopyr Human Health Risk Assessment DP# D426071

Page 27 of 37 

### For adults and children 3 to <6 years old

, a total ARI was used since the POD ( 5 mg/kg/day from the subchronic oral rat toxicity study with acid form) for the oral and inhalation exposure routes were the same, but the LOC values for oral exposure (100) and inhalation exposure (1000) are
different

. The target ARI is 1; therefore, ARIs of less than 1 are risk estimat es of concern. For
adults and children 3 to <6 years old, the short

- term aggregate ARI s are greater than 1 ; therefore,
risk estimates do not exceed HED’s LOC.

Table 7.2. 2. Shor t

- and Intermediate

- Term Aggregate Risk Cal culations Using ARI Approach. 1

Population Short

- Term Scenario

Dietary Exposure 2 Oral Residential Exposure 3 Dermal
Residential Exposure Inhalation
Residential Exposure 4 Aggregate ARI (food, water, and residential) 5 MOE ARI MOE ARI MOE ARI MOE ARI
Adu lts 20 to 49 years old (sprinkler can applications) 5 00 5. 0 NA NA NA NA 1,900 1.9 1.4

Children 3 to <6 years old 36 4 3.6 45,000 450 NA NA 5 23 ,000 52 0 3.6

1. HED is concerned if the ARI is less than 1. ARI = Aggregate Risk Index.
2. MOE dietary = [(short

- term oral NOAEL)/(chronic dietary exposure)]. ARI dietary = [(MOE dietary)/(MOE target)]. Short

- term oral NOAEL = 5 mg/kg/day; chronic dietary exposure for a dul ts 20 to 49 years old = 0.0 10008 mg/kg/day; c hronic dietary exposure for
children 3 to 5 years old = 0.01 37791 m g/kg/day. MOE target = 100.
3. MOE oral residential exposure = [(short

- term oral NOAEL)/(high

- end incident al oral residential exposure)]. ARI oral residential exposure = [(MOE oral residential expo sure)/(MOE target)]. Short

- term oral NOAEL = 5 mg/kg/day; high

- end incident al oral
resi dential exposure for children 3 to <6 years old (swimmer) = 0. 00001104 mg/kg/day. MOE target = 100.
4. MOE inhalation residential exposure = [(short

- term inhalation NOAEL )/( high

- end inhalation residential exposure)]. ARI inhalation = [(MOE inhalation residential exposure )/(MOE target)]. Short

- term inhalation NOAEL = 5 mg/kg/day; high

- end inhalation residential exposure for adults = 0.0 026 mg/kg/day (M/L /A liquids to turf with sprinkler can ); high

- end inhalation residential exposure for
children 3 to <6 years old = 0.00000955 mg/kg/day ( swimmer) . MOE target = 1000

. 5. ARI Aggregate = 1/[(1/ARI dietary) + (1/ARI oral) + (1/ARI inhalation)]

.



### 7.3 Chronic Aggregate Risk

A long

- term aggregate risk assessment was not performed, because long

- term residential exposure to triclopyr (i.e., >6 months) is unlikely to occur based upon the use patterns. Specifically, in the case of triclopyr, the chronic aggregate risk is composed o f exposures to triclopyr residues in food and drinking water and is equivalent to the chronic dietary risk discussed in Section 5.4.4. As shown in Table 5.4.5, the chronic risk estimates do not exceed the HED’s LOC for the general U.S. population and all population subgroups.

8.0 Cumulative Exposure/Risk Characterization

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 triclopyr and any other substances

. R isk assessment of TCP derived from multiple chemicals
has been conducted i n a separate document (Memo, W. Donovan et al. , 06

- JUN

- 2002, D283101). The conclusions of the 2002 TCP assessment that acute and chronic dietary

aggrega te exposure estimates are below HED’s level of concern are still considered valid. For the purposes of this tolerance action, therefore, EPA has not assumed that triclopyr 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 Office of Pesticide Programs concerning common m echanism determinations and procedures for cumulating effects from substances found to have a common mechanism on EPA’s website atTriclopyr Human Health Risk Assessment DP# D426071

Page 28 of 37 

### http ://www.epa.gov/pesticide

- science

- and

- assessing

- pesticide

- risks/cumulative

- assessment

- risk

pesticides

.

9.0 Occupational Exposure/Risk Characterization

The proposed action to remove a grazing restriction for dairy cattle is not expected to result in
additional occupational exposures; and the proposed registration of the choline salt is covered by the previous actions. As a result, no new occupational assessments have been conducted for
these actions . However, occupational handler inhalation exposure and risk estimates were updated to reflect all of the currently registered uses of triclopyr for the July 2014 HASPOC meeting in order to assess the inhalation waiver request submitted by the triclopyr registrants.
The inhalation risk estimates for the registered forestry use triggered the requirement of a route

specific inhalation study (i.e., inhalation MOEs <1000) ; therefore, a 10X UF DB 

### was applied to all
inhalat ion exposure scenarios. However , as a par t of this updated assessment, inhalation exposure and risks for the rangeland and pasture uses were updated and were not of concern (MOEs >1000). A summary of the occupational handler inhalation risk estimat es are presented
in Attachment 3.

Restricted Entry Interval : Triclopyr acid is classified as Toxicity Categories III and IV via the dermal route and Toxicity Category IV for skin irritation potential. It is not a skin
sensitizer. Under 40 CFR 156.208 (c) (2), ai’s classified as Acute III or IV for acute dermal, eye irritation and primary skin irritation are assigned a 12

- hour REI. Therefore, the [156 subpart K] Worker Protection Statement (WPS) interim REI of 12 hours is adequate to protect agricultural workers from post

- application exposures to triclopyr choli ne salt. HED would recommend a REI
of 12 hours. This is the REI listed on the proposed triclopyr choline salt labels, and is considered protective of post

- application exposure.

RDI: RAB1 Branch (3/19/2015); G. Kramer ( 2 / 4/16 ); C. Smith ( 2 / 4/16 ) J. Tyler:S10943:PY

- S:(703)305

- 5564:7509P:RAB1Triclopyr Human Health Risk Assessment DP# D426071

Page 29 of 37 

### Attachment 1

. Toxicology Profile and Executive Summaries

.

A.1 Toxicology Data Requirements

Study requirements (40 CFR 158.340) for use of triclopyr. Use of the new guideline numbers does not imply that the new (1998) guideline protocols were used.

Table A.1.1. Toxicology Data Requirements.

Study Technical Required Satisfied 870.1100 Acute Oral Toxicity

................................ ....................... 870.1200 Acute Dermal Toxicity

................................ .................. 870.1300 Acute Inhalation Toxicity

................................ .............. 870.2400 Acute Eye Irritation

................................ ....................... 870.2500 Acute Dermal Irritation

................................ ................. 870.2600 Skin Sensitization

................................ .......................... yes
yes
yes
yes
yes
yes yes
yes
yes
yes
yes
yes 870.3100 90

- Day Oral Toxicity in Rodents

................................ .. 870.3150 90

- Day Oral Toxicity in Nonrodents

............................. 870.3200 21/28

- Day Dermal Toxicity

................................ .......... 870.3250 90

- Day Dermal Toxicity

................................ ............... 870.3465 90

- Day Inhalation Toxicity

................................ ........... yes
yes
yes

no
yes 1 yes
yes
yes

--

no 870.3700a Prenatal Developmental Toxicity (rodent)

.................... 870.3700b Prenatal Developmental Toxicity ( nonrodent)

.............. 870.3800 Reproduction and Fertility Effects

................................ yes
yes
yes yes
yes
yes 870.4100a Chronic Toxicity (rodent)

................................ .............. 870.4100b Chronic Toxicity (nonrodent)

................................ ........ 870.4200a Carcinogenicity (rat)

................................ ...................... 870.4200b Carcinogenicity (mouse)

................................ ............... 870.4300 Combined Chronic Toxicity/Carcinogenicity

............... yes
yes
yes
yes
yes yes 2

yes
yes 2

yes
yes 870.5100 Mutagenicity

— Bacterial Reverse Mutation Test

.......... 870.5300 Mutagenicity

— Mammalian Cell Gene Mutation Test

.. . 870.5xxx Mutagenicity

— Structural Chromosomal Aberrations

.. . 870.5xxx Mutagenicity

— Other Genotoxic Effects

....................... yes
yes
yes
yes yes
yes
yes
yes 870.6200a Acute Neurotoxicity Screening Battery (rat)

................. 870.6200b Subchronic Neurotoxicity Screening Battery (rat)

........ 870.6300 Developmental Neurotoxicity

................................ ....... no 3

yes

no -- yes

-- 870.7485 Metabolism and Pharmacokinetics

................................ 870.7600 Dermal Penetration

................................ ........................ 870.7800 Immunotoxicity

................................ ............................. yes
yes
yes Y es
yes
yes
1. HASPOC concluded that the subchronic inhalation study is required at this time (J. Leshin; TXR#0057009 ).
2. The combined chronic toxicity/carcinogenicity study satisfies the requirement of the study.
3. HASPOC concluded that the ACN is not required at this time (J. Leshin; TXR#0057009).Triclopyr Human Health Risk Assessment DP# D426071

Page 30 of 37 

### A.2 Toxicity Profile s

Table A.2.1. Acute Toxicity Profile

– Triclopyr Acid.
Guideline No. Study Type MRID Results Toxicity Category

870.1100 Acute oral 00031940 LD 50 = 729 mg/kg (M)
LD 50 = 630 mg/kg (F) III

870.1100 Acute oral 45451304 Combined LD 50 = 1915 mg/kg III

870.1200 Acute dermal 00056009 LD 50 >2000 mg/kg III

870.1200 Acute dermal 45451305 LD 50 >5050 mg/kg IV

870.1300 Acute inhalation 45451306 LC 50 >2.56 mg/L IV

870.2400 Primary eye irritation 45451307 moderate irritant III

870.2500 Primary skin irritation 45451308 mild irritant IV

870.2600 Dermal sensitization 45451309 not a sensitizer

--

Table A.2.2. Acute Toxicity Profile

– Triclopyr Triethylamine Salt.
Guideline No. Study Type MRID(s) Results Toxicity Category
870.1100 Acute oral 41443301 LD 50 = 1847 mg/kg III

870.1200 Acute dermal 41443302 LD 50 >2000 mg/kg III

870.1300 Acute inhalation 41443303 LC 50 >2.6 mg/L III
870.2400 Primary eye irritation 41443304 corrosive I
870.2500 Primary skin irritation 41443305 not irritating IV
870.2600 Dermal sensitization 41443306 sensitizer

--

Table A.2.3. Acute Toxicity Profile

– Triclopyr Butoxyethyl Ester.

Guideline No. Study Type MRID(s) Results Toxicity Category

870.1100 Acute oral 40557004 LD 50 = 803 mg/kg III
870.1200 Acute dermal 40557005 LD 50 >2000 mg/kg III
870.1300 Acute inhalation 40557006 LC 50 > .8 mg/L III
870.2400 Primary eye irritation 40557007 minimally irritating III
870.2500 Primary skin irritation 40557008 not irritating IV
870.2600 Dermal sensitization 40557009 sensitizer

--

Table A.2.4. Subchronic, Chronic
, and Other Toxicity Profile

– Triclopyr.

Guideline No. Study Type MRID No. (year)/
Classification /Doses Results

870.3100 90

- Day Oral Toxicity in Rodents (rat)

Acid form 00150378 (1984) Acceptable 0, 5, 20, 50, or 250 mg/kg/day NOAEL = 5 mg/kg/day

. LOAEL = 20 mg/kg/day based on degeneration of the proximal tubules of the kidneys

.

870.3100 90

- Day Oral Toxicity in Rodents (rat)

Ester form 42274901 (1992) Supplementary 0, 7, 28, 70, or 350 mg/kg/day NOAEL = not established

. LOAEL = 7 mg/kg/day (F) based on decreased red blood cell content, hemoglobin content, and packed cell volume
in females. Degeneration of the proximal tubules of the kidneys was seen in males at 70 and 350 mg/kg/day and
females at 350 mg/kg/day (HDT).

870.3150 183

- Day Oral Toxicity in Non

Rodent (dog) 00071794 (1976) Acceptable 0, 0.1, 0.5, or 2.5 mg/kg/day NOAEL = 2.5 mg/kg/day

. LOAEL = not established

.

Non

- significant decreased rate of phenolsulfothalein (PSP) due to competition between triclopyr and PSP for
renal excretion

.Triclopyr Human Health Risk Assessment DP# D426071

Page 31 of 37 Table A.2.4. Subchronic, Chronic
, and Other Toxicity Profile

– Triclopyr.

Guideline No. Study Type MRID No. (year)/
Classification /Doses Results

870.3200 21

- Day Dermal Toxicity (rabbit)

Ester form 42212701 (1992) Acceptable 0, 100, 500, or 1000 mg/kg/day NOAEL = 1000 mg/kg/day

. LOAEL = not established

.

Decreased alkaline phosphatase in both sexes at 1000 mg/kg/day and increased absolute and relative liver weights in males at 1000 mg/kg/day considered marginal and not biologically significant

.

870.3700a Prenatal Developmental in Rodent (rat)

Ester form 43675801, 45168801 (1994) Acceptable/guideline 0, 5, 30, 100

, or 300 mg/kg/day Maternal NOAEL = 100 mg/kg/day

. Maternal LOAEL = 300 mg/kg/day based on mortality, clinical signs, necropsy findings, decreased food consumption, increased water consumption, and increased
relativ e kidney and liver weights.

Developmental NOAEL = 100 mg/kg/day

. Developmental LOAEL = 300 mg/kg/day based on incidence of hydrocephalus, cleft palate, microphthalmia/anophthalmia, retinal folds, thin diaphragm/protrusion of the liver, decrease fetal weig ht,
and visceral and skeletal anomalies and variants

.

870.3700a Prenatal Developmental in Rodent (rat)

Salt form 43217602 (1994) Acceptable/guideline 0, 30, 100

, or 300 mg/kg/day Maternal NOAEL = 100 mg/kg/day

. Maternal LOAEL = 300 mg/kg/day based on mortality.

Developmental NOAEL = 100 mg/kg/day

. Developmental LOAEL = 300 mg/kg/day based on decreased fetal weights, increased fetal and litter incidence of skeletal anomalies, and increased fetal
incidence of unossified sternebrae

.

870.3700a Prenatal Developmental in Rodent (rat)

Acid form 00072441, 41688301, 92189024 (1979) Acceptable/guideline 0, 50, 100, or 200 mg/kg/day Maternal NOAEL = not established

. Maternal LOAEL = 50 mg/kg/day based on increased clinical signs.

Developmental NOAEL = 100 mg/kg/day

. Developmental LOAEL = 200 mg/kg/day based on
increased incidence of fetuses and litters with retarded ossification of skull bones and two litters (1 fetus per litter) with cleft palate and brachycephaly

.

870.3700b Prenatal Developmental in
Non

- Rodent (rabbit)

Ester form 43217601 (1994)
Core

- minimum 0, 10, 30, or 100 mg/kg/day Maternal NOAEL = 30 mg/kg/day

. Maternal LOAEL = 100 mg/kg/day based on mortality

.

Developmental NOAEL = 30 mg/kg/day

. Developmental LOAEL = 100 mg/kg/day based on
decreased total live fetuses and increased total fetal deaths
and increased fetal and/or litter incidence of skeletal
anomalies and variants

.

870.3700b Prenatal Developmental in
Non

- Rodent (rabbit)

Salt form 43217603 (1994)
Core

- minimum 0, 10, 30

, or 100 mg/kg/day Maternal NOAEL = 30 mg/kg/day

. Maternal LOAEL = 100 mg/kg/day based on mortality, abortions, decreased food efficiency, increased liver and kidney weights

.

Developmental NOAEL = 30 mg/kg/day

. Developmental LOAEL = 100 mg/kg/day based on decreased live fetuses and increased embryonic deaths
due to abortions

.

870.3800 Reproduction and Fertility Effects (rat)

Acid form 43545701 Acceptable/guideline 0, 5, 25, or 250 mg/kg/day Parental NOAEL = 5 mg/kg/day

. Parental LOAEL = 25 mg/kg/day based on increased incidence of proximal tubular degeneration in both sexes

.

Offspring NOAEL = 5 mg/kg/day

. Offspring LOAEL = 25 mg/kg/day based on increased
incidences of F 2 pups with exencephaly and ablephariaTriclopyr Human Health Risk Assessment DP# D426071

Page 32 of 37 Table A.2.4. Subchronic, Chronic
, and Other Toxicity Profile

– Triclopyr.

Guideline No. Study Type MRID No. (year)/
Classification /Doses Results

870.4100 b 228

- Day Toxicity Study (dog)

Acid form 00071794(1976)
Core

- minimum 0, 5, 10

, or 20 mg/kg/day NOAEL = 10 mg/kg/day

. LOAEL = 20 mg/kg/day based on decreased hematological parameters, changes in clinical chemistry and liver histopathology

.

870.4100b 1

- Year Chronic Toxicity (dog) 41200301(1988) Acceptable (with 228 day study) 0, 0.5, 2.5, or 5 mg/kg/day NOAEL = 5 mg/kg/day

. LOAEL = not established

.

Changes in clinical chemistry noted are due to a physiological response of the dog based on limited ability of the dog to excrete orga nic acids at higher plasma
concentration

. 870.4200a Carcinogenicity (rat) See 870.4300 See 870.4300

870.4200b Carcinogenicity (mouse) 40356601 (1987)
Core

- minimum 0, 5.09/5.55, 26.5/28.6, or 135/143 mg/kg/day (M/F) NOAEL = 26.5/28.6 mg/kg/day (M/F)

. LOAEL = 135/143 mg/kg/day (M/F)] based on decreased weight gains

.

No evidence of carcinogenicity in males, but females had a significant trend (p<0.05) for mammary gland
adenocarcinomas

.

870.4300 Combined Chronic Toxicity/ Carcinogenicity (rat) 40107701 (1987)
Core

- minimum 0, 3, 12

, or 36 mg/kg/day NOAEL = 36 mg/kg/day

. LOAEL = not established

.

Marginal increase in proximal tubular degeneration
observed at 6 months

.

Increase in adrenal gland pheochromocytoma in males and significant trend (p<0.05) for mammary gland
adenocarcinomas in females.

870.5265 Gene mutation

Ester form 41732202 Non

- mutagenic up to 5,000 μg/plate or cytotoxic levels, in presence and absence of activation, in S. typhimurium strains TA98, TA100, TA1535, and TA1537

.

870.5265 Gene mutation

Acid form 00031939 (1975) Supplementary Non

- mutagenic up to 10,000 μg/plate or cytotoxic levels, in presence and absence of activation, in S. typhimurium strains TA98, TA100, TA1535, TA1537, and TA1538

.

870.5300 Gene mutation

Acid form 00038408 (1980) Acceptable No evidence of growth inhibition for the repair competent (H17) or repair deficient (M45) B. subtilis baceterial strains when tested up to 2,000 μg/disk

.

870.5300 Gene mutation

Acid form 00057085 (1973) Acceptable Negative for mutagenicity at doses up to 70 mg/kg in ICR random bred mice when tested against indicator organisms

.

870.5395 In vivo Cytogenetic Assay (rat)

Acid form 00057086 (1973) Acceptable Negative for chromosomal aberrations in the cytogenetic assay when administered as a single dose or for 5 days up to 70 mg/kg/day

.

870.5395 In vivo Mouse
Micronucleus

Ester form 41747101 (1990) Acceptable Not clastogenic up to 600 mg/kg (HDT)

.

870.5450 Dominant lethal assay (mouse)

Acid form 00028996 (1980) Acceptable Negative at doses up to 70 mg/kg/day

.

870.5450 Dominant lethal assay (rat)

Acid form 00057087 (1973) Acceptable Negative at doses up to 70 mg/kg/day

.

870.5550 Unscheduled DNA synthesis

Ester form 41747102 (1990) Acceptable Did not cause DNA damage or inducible repair

.Triclopyr Human Health Risk Assessment DP# D426071

Page 33 of 37 Table A.2.4. Subchronic, Chronic
, and Other Toxicity Profile

– Triclopyr.

Guideline No. Study Type MRID No. (year)/
Classification /Doses Results

870.5550 Unscheduled DNA synthesis

Acid form 40057702 (1986) Acceptable No evidence of unscheduled DNA synthesis

.

870.6200 Subchronic Neurotoxicity Screening Battery (rat)

Acid form 49306303 (2012) Acceptable/guideline 0, 5, 25, or 200 mg/kg/day NOAEL = 25 mg/kg/day

. LOAEL = 200 mg/kg/day based on decreased body weights and food consumption in males

.

870.7485 Metabolism and
Pharmacokinetics 41353001 (1988) Acceptable/guideline 3 or 60 mg/kg/day Regardless of dose level or route of administration, triclopyr was well absorbed with peak plasma levels
reached within 3

- 4 hours. Radioactivity in the tissues at 72 hours was minimal (<0.54%). At the low dose, >90% of the radioactivity was excreted with in 24 hours primarily via the urine. The high dose yielded similar overall results except that urinary elimination was
decreased between 0

- 12 hours due to saturation of renal excretion mechanisms. Unmetabolized parent represented >90% of the urinary radi oactivity.

870.7600 Dermal Penetration Study (Human)

Ester form 45253601 (1989) Supplementary 3.7 mg/kg; 8 hour exposure; observed up to 84 hours after dosing In an oral and dermal pharmacokinetics study of triclopyr in human volunteers, triclopyr was administered orally and dermally to six human volunteers. More than 80% of the administered dose was found as unchanged triclopyr
in the urine. An average of 1.65% of the dermally applied dose was recovered in the urine and represented dermal penetration of triclopyr.

870.7600 Dermal Penetration Study (rabbit)

Acid form 00153805 (1981) Acceptable 2 g/kg 1.5% of an applied dose absorbed through the skin

.

870.7800 Immunotoxicity 49433001 (2011) Acceptable/guideline 0, 10, 50, or 250 mg/kg/day Systemic NOAEL = 50 mg/kg/day

. Systemic LOAEL = 250 mg/kg/day based on decreased body weights and food consumption

.

Immunotoxicity NOAEL = 250 mg/kg/day

. Immunotoxicity LOAEL = not established

.Triclopyr Human Health Risk Assessment DP# D426071

Page 34 of 37 

### A ttachment 2

. Summary of US and International Tolerances and Maximum Residue
Limits.

Summary of US and International Tolerances and Maximum Residue Limits. Residue Definition : US Canada Mexico 1 Codex US [40 CFR §180.417 (1) Tolerances for residues of the herbicide triclopyr per se, as a result of the application/use of butoxyethyl ester of triclopyr and triethylamine salt of triclopyr 2

- [(3,5,6

- trichloro

- 2

- pyridinyl)oxy]acetic acid None

Commodity Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico 1 Codex

Milk 0.03 0.01 Milk, fat 0.07

Livestock: US [40 CFR §180.417 (2) Tolerances for the combined residues of the herbicide triclopyr ((3,5,6

- trichloro

- 2

- pyridinyl)oxy) acetic acid and its metabolite 3,5,6

- trichloro

- 2

- pyridinol (TCP), as a result of the application/use of butoxyethyl ester of triclopyr or the triethylamine salt of triclopyr All commodities, except milk: 2

- [(3,5,6

- trichloro

- 2

- pyridinyl)oxy]acetic acid, including the metabolite 3,5,6

- trichloro

- 2

- pyridinol None

Commodity Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico 1 Codex

Meat* 0.08 0.1
Fat* 0.08 0.1 Meat byproducts*

0.70 0.1 meat byproducts of cattle, goats, horses, hogs, and sheep (except kidney and liver)

0.5 kidney, liver (of cattle, goats, horses, hogs, and sheep)

* of cattle, goats, horses, hogs, and sheep

Completed: M. Negussie; 03/25/15Triclopyr Human Health Risk Assessment DP# D426071

Page 35 of 37 

### Attachment 3. Summary of Updated Occupational Handler Inhalation Exposure and Risk
Estimates for July 2014 HASPOC Meeting.

Occupational handler inhalation exposure and risk estimates were updated to reflect all of the currently registered uses of triclopyr for the July 2014 HASPOC meeting in order to assess the inhalation waiver request submitted by the triclopyr registrants. Additionally, since the July 2014 meeting, application rates for the aerial applications by h elicopter have been changed to reflect a maximum labeled rate of 6 lb ae/A (rather than the 9 lb ae/A assumed for the July 2014 meeting).

For mixers/loaders of the liquid formulation for aerial application by helicopter to forestry, the
inhalation MOE is 41. The current label requires baseline PPE (single layer clothing with gloves). With the addition of a PF5 or PF10 respirator to the label, MOEs for this scenario would increase to 200 and 410, respectively. These estimates are considered conservative given aerial applications are only made by helicopter and the high acreage default of 7,500 acres would be an overestimate of the acreage that would be treated. Previously, data was obtained from the U.S. Army Corps of Engineers, University of South Flori da, and the South Florida Water Management District that indicated typical acreage treated with triclopyr by helicopter was 100 acres (J. Swackhammer; 22

- JUL

- 2002; D269448). This estimate was not used for calculating
MOEs for this evaluation because it is based on informal discussions from over a decade ago and commercial users were not included the estimate. More current, all

- inclusive data regarding the typical acreage that is treated with triclopyr using aerial applications by helicopter would be
neede d to refine this exposure scenario.

Based on a weight of evidence approach and considering all of the available triclopyr hazard and exposure data , HASPOC concluded that a subchronic inhalation study is required at this time for triclopyr. As a result, a 10X database uncertainty factor was retained for assessing risk for inhalation exposure scenarios

.Triclopyr Human Health Risk Assessment DP# D426071

Page 36 of 37 Table 9.1. Triclopyr: Summary of Occupational Handler Inhalation Risks for Currently Registered Uses.

Activity Application Equipment Crop/Target Inhalation
Unit Exposure (μg/lb ai) 1 App Rate 2 Acres 3 Dose 4 ST and IT
Inhalation
MOE (Baseline) 5 Mitigation
Level
Mixer/Loader Groundboom app. of liquid formulation Range and pasture, forests and non

- crop areas, including manufacturing and storage sites, rights

- of

- way such as electrical power lines, communication lines, pipelines, roadsides, railroads, fence rows, non

- irrigation ditch banks, and around farm buildings; and applications to grazed areas, and
establishment and maintenance o f wildlife openings, and in Christmas tree plantations and aquatic sites. 0.219 (baseline) 0.0438 (PF5) 9 lb ae/A 80 0.00198 2,500

Aerial/Helicopter app. of liquid formulation 6 lb ae/A 7,500 0.123 41
0.0246 200 (PF5)

0.00123 410 (PF10)

Groundboom app. of liquid formulation Rice 0.219 (baseline) 0.375 lb ae/A
0.373 lb ae /A 200 0.000205 24,000

Aerial app. of liquid
formulation 1,200 0.00123 4,100

Applicator
Applicator, Aerial/Helicopter Range and pasture, forests and non

- crop areas, including manufacturing and storage sites, rights

- of

- way such as electrical power lines, communication lines, pipelines, roadsides, railroads, fence rows, non

- irrigation ditch banks, and around farm buildings; and applications to grazed areas, and

e stablishment and maintenance of wildlife openings, and in Christmas tree plantations and aquatic sites. 0.0049 (EC) 6 lb ae/A 7,500 0.00414 1,200 (EC)

Applicator, Open Cab
Groundboom 0.34 (baseline) 9 lb ae/A 200 0.00306 1,600

Applicator, Aerial
Rice 0.0049 (EC)
0.375 lb ae/A 1,200 0.000027
6 180,000 (EC)

Applicator, Open Cab
Groundboom 0.34 (baseline) 200 0.000040
4 16,000

Mixer/Loader/Applicator

M/L/A Backpack Range and pastures and in non

- crop areas including industrial manufacturing and storage sites, rights

- of

- way such as electrical power lines, communications lines, pipelines, roadsides, railroads, fence rows, non

irrigation ditch banks and around farm build ings. Use on these sites may include application to grazed areas, as well as establishment and maintenance of wildlife openings. 2.58 8 lb ae/A or 0.75 lb ae/gal 40 gallons 0.000968 5,200

M/L/A spray boom, handgun, or other suitable equipment mounted on a boat or vehicle, helicopter. Aquatic Sites: For control of immersed, submersed and floating aquatic plants in aquatic sites such as ponds, lakes, reservoirs, non

- irrigation canals and ditches which have little or no continuous outflow, marshes and
wetlan ds, including broadleaf and woody vegetation on banks and shores within or adjacent to these and other aquatic sites. 3.9 6 lb ae/A or
8.436 lb ae/A/100 gal
or 0.08436 lb

ae /gal 1,000 gallons 0.00411 1,200Triclopyr Human Health Risk Assessment DP# D426071

Page 37 of 37 Table 9.1. Triclopyr: Summary of Occupational Handler Inhalation Risks for Currently Registered Uses.

Activity Application Equipment Crop/Target Inhalation
Unit Exposure (μg/lb ai) 1 App Rate 2 Acres 3 Dose 4 ST and IT
Inhalation
MOE (Baseline) 5 Mitigation
Level

M/L/A Handheld sprayer Cool season turfgrass, a nd on non

- crop areas including industrial sites, rights

of

- way (such as roadsides, electric utility and communication transmission lines, pipelines and railroads), non

- irrigation ditch banks, natural areas (such as wildlife management areas, wildlife openi ngs, wildlife habitats, recreation areas, campgrounds, trailheads and trails) and grazed areas in and around
these sites 30 2.0769 lb ae /A 2.9 fl oz/gal
0.23 lb ae /gal 40 gallons 0.00345 1,400

Flagger

Aerial spray app. Rice

0.35 (baseline) 0.375 lb ae/A

350 0.000574 8,700 Range and pasture, forests and non

- crop areas, including manufacturing and storage sites, rights

- of

- way such as electrical power lines, communication lines, pipelines, roadsides, railroads, fence rows, non

- irrigation ditch banks, and around farm buildings; and applications to grazed areas, and establishment and maintenance of wildlife openings, and in Christmas tree plantations and aquatic sites. 9 lb ae/A 0.0138 360

1. Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE (gloves), Eng. Controls.
2. Based on proposed labels.
3. Exposure Science Advisory Council Policy #9.1.
4. Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre) × Area Treated (A/day) x IAF (100 %) ÷ BW (80 kg).
5. Inhalation MOE = Inhalation NOAEL (5 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).