UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D

. C

., 20460

P CCode.: 17 9 701

DP Barcode: 411 4 05

Date : 1 2/05/2014

MEMOR AN DUM

T o:

Th rough: d-Limonene : Ecolog i cal Ri sk Assessmen t fo r Regi stration Review

Nell Anderson, Branch Ch ie f

R

isk Management and Implementat i on Branch

Pesti cide Re-evalua t ion D i vision

Dana Spatz, Branch Chief

Environme ntal Ri s k Branch l ll

Environmen tal F ate and EffectS Division



### From: for James K. Wolf, Ph

. D., So il Phys i c is t

Katherine Stebbins

, Biologist

Env i ronmenta l Ris k Branch Ill

Environmenta l Fate and Ef f ects D i vis i o n

Pee r Review : Melissa Pang e r, Ph.D., Senior Scientist

James Hetrick Ph.D., Senior Adviso r

R

osanna Louie-Juzwiak RAPL

Environme n tal Risk Branch Ill

Env i ronmenta l Fa te and Effects Divisi o n

This memorandum transmits the Environmental F ate an d Effects Division's (E FED) ecological

r i sk assessmen t for d

- li monene. The resul ts o f this screen i ng- l ev el risk assessment in dicate :

Fo r broadcast/directed spray applications of d

· · llmonene :

The rnajor r i sk concer ns a re for pote nt i a l effects t o te rr estria l inverte b rates. Although

there are no toxi ci ty data t o derive: risk quotie nts , r is k is assumed based o n the fact that

th is pes ti cide is registered fo r use as an i nsec tici de.2

 The level of concern is also exceeded for non

‐ target plants inhabiting areas near the

treated field ( i.e., within 15 feet).

 Acute and chronic risk has been identified for mammals. Although this chemical is

practically non

‐ toxic to mammals, the risk identified in this assessment can be attributed

to very high application rates ( i.e., up to 55 lb a.i./A).

 Effects are not expected for birds (and reptiles) at the lower rates modell ed and risks

are uncertain at the higher rates ( e.g., 34 and 55 lb a.i./A). Risk to birds on a chronic

exposure basis is also uncertain due to a lack of data.

 Effects are not expected for fish, amphibians, aquatic invertebrates and plants.

For small scale applications of d

‐ limonene (aerosol spray, crack and crevice, etc.):

 Effects to mammals, birds, plants and aquatic animals are not expected

 Effects to terrestrial invertebrates are of concern.

At this time, there have been no data submitted to assess the risk to pollinators. d

‐ limonene is

registered for use as an insecticide and is generally applied via foliar applications, thus, data are

needed in order to conduct an assessment for pollinators; namely, bees. The following studies

are recommended to support this assessment.

These studies include:

1. Honey Bee Adult Acute Contact Toxicity (Guideline 850.3020)

2. A cute oral toxi city to adult honey bees (Non

‐ guideline, OECD TG 213)

3. A cute oral toxicity to larval honey bees (Non

‐ guideline, OECD TG 237)

4. C hronic oral toxicity to adult honey bees (Non

‐ guideline)

5. Chronic oral toxicity to larval honey bees (Non

‐ guideline)

6. Honey bee toxicity of residues on foliage (Guideline 850.3030)

7. Field trial of residues in pollen and nectar (Non

‐ guideline)

8. Semi

‐ field testi ng for pollinator (Non

‐ guideline, OECD Guidance 75)

9. Field testing for pollinators (Guideline 850.3040)3

I. EXECUTIVE SUMMARY

A. Nature of the Stressor

Limonene ( d

‐ limonene) [(4 R )

‐ 1

‐ methyl

‐ 4

‐ (1

‐ methylethenyl)cyclohexene; CAS No, 5989

‐ 27

‐ 5] is a

naturally occurring chemical obtained from the rind of citrus fruits. Limonene is a hydrocarbon

classified as a cyclic terpene. The chemical exists as two optical isomer s, d‐ and l‐ limonene, and

the d/l‐ racemic mixture. The limonene enantiomer, or active ingredient (a.i.) under review is the

d

‐ enantiomer (i.e., the dextrorotatory enantiomer). This dextrorotatory enantiomer has the R‐

absolute configuration. In this assessment, unless otherwise specified, the term “limonene” is

used interchangeably with “ d

‐ limonene.”

d‐ limonene is used as an acaricide, herbicide, insecticide, and also as an insect repellent/feeding

depressant. There are a variety of uses registered including: agricultural crops (citrus, pome

fruits, grapes, etc. ), ornamental plants, Christmas tree plantations, fencerows, recreational

areas, wood protection, and many indoor uses (see Appendix 1 for a comprehensive listing of the

types of registered uses). Limonene is not applied aerially. Limonene can be applied using

sprayers (ready

‐ to

‐ use containers, hooded sprayers, pump sprayers, pressurized containers),

aerosol containers (cans), impregnated strips, injection equipment or with a sponge. The labels

for the d‐ limonene registrations suggest a wide range of potential treatment areas [ i.e., spot

treatment (ft 2 ) to crops (acres)]. With applications such as spot treatments or edge/perimeter

treatments, the application rates used in the exposure models often lead to uncertainty in the

exposure estimates ( e.g., scaling spot treatment applications up to an acre). The maximum

number of applications and maximum yearly application rate, and reapplication interval are also

not specified for many regis trations (labels).

There is a wide range of application rates when a treatment area is specified with rates that

range from 4.6 to 55.2 lb a.i./A per application for treating ornamentals and for herbicidal use in

agricultural crops. The maximum yearly rate is 415.2 lb a.i./A/yr.

The insecticidal mode of action of limonene is believed to be similar to pyrethrum

‐ by affecting

the sensory nerves of the peripheral nervous system (not a cholinesterase inhibitor) 1

. As an

herbicide, d

‐ limonene is a non

‐ systemic, contact herbicide that strips the waxy rind or cuticle

from plants, causing death of the plant by desiccation 2

.

The major route of dissipation for d

‐ limonene is volatilization. Other dissipation processes

include photodegradation in air, microbial

‐ mediated aerobic soil metabolism, sorption to soil,

and transport in runoff water. Limonene is stable to hydrolysis. The vapor pressure (2 mm Hg @

20  ̊ C) and Henry’s Law Constant (2.6 x 10

‐ 2 atm

‐ m 3 /mole) indicates that limonene is highly

volatile and that it will readily volatilize from soil and water. However, this dissipation process

competes with binding. Limonene binds strongly to soil (K

oc > 1000 mL/g

oc ), therefore it is

1 Ware, G.W. and Whitacre, D.M. 2004. The Pesticide Book. 6 th Edition. Pg. 66

2 Stephen O. Duke, Joanne G. Romagni, Franck E. Dayan 2000. Natural products as sources for new mechanisms of herbicidal action. Crop

Protection 19 (2000) 583-589.4

expected to be relatively immobile in soils. Because aerobic metabolism studies have not been

submitted for d‐ limonene, published aerobic biodegradation studies were used to estimate a

first order biotransformation rate with a half

‐ life of 38.5 days. Under anaerobic conditions, d

‐

limonene appears to be persistent.

B. Summary of Effects and Risk Conclusions

For broadcast/directed spray applications of d

‐ limonene:

o The major risk concerns are for potential effects to terrestrial invertebrates.

Although there are no toxicity data to derive risk quotients, risk is assumed based

on the fact that this pesticide is registered for use as an insecticide.

o The level of concern is also exceeded for non

‐ target plants inhabiting areas near

the treated field ( i.e., within 15 feet).

o Acute and chronic risk has been identified for mammals. Although this chemical is

practically non

‐ toxic to mammals, the risk identified in this assessment can be

attributed to very high application rates ( i.e., up to 55 lb a.i./A).

o Effects are not expected for birds (and reptiles) at the lower rates modelled and

risks are uncertain at the higher rates ( e.g., 34 and 55 lb a.i./A). Risk to birds on a

chronic exposure basis is also uncertain due to a lack of data.

o Effects are not expected for fish, amph ibians, aquatic invertebrates and plants.

For small scale applications of d

‐ limonene (aerosol spray, crack and crevice, etc.):

o Effects to mammals, birds, plants and aquatic animals are not expected

o Effects to terrestrial invertebrates are of concern

.

II. PROBLEM FORMULATION

A. Pesticide Type, Class, and Mode of Action

Limonene ( d

‐ limonene) [(4 R )

‐ 1

‐ methyl

‐ 4

‐ (1

‐ methylethenyl)cyclohexene; CAS No, 5989

‐ 27

‐ 5] is a

naturally occurring chemical obtained from the rind of citrus fruits. Limonene is a hydrocarbon

classified as a cyclic terpene. Specifically, it is a monoterpene. Limonene has a chiral

(stereogenic) carbon. Thus, limonen e occurs as an enantiomeric pair (i.e., as two non

‐ superimposable mirror

‐ image chemical structures and therefore, each enantiomer is optically

active 3

. The structure of d

‐ limonene is shown in Figure 1

. The limonene enantiomer under review

is the d

‐ enantiomer (i.e., the dextrorotatory enantiomer). This dextrorotatory enantiomer has

the R‐ absolute configuration. In this assessment, unless otherwise specified, the term

“limonene” is used interchangeably with “ d

‐ limonene.”

3 The chirality of limonene arises from an asymmetric carbon atom (i.e., carbon is the chiral/stereogenic center). The odors of l

‐

limonene and d

‐ limonene are different; l

‐ limonene smells piney and turpentine like and d

‐ limonene has a pleasing orange

scent. This is associated with enantiomer

‐ specific interactions with chiral olfactory receptors

.5

Figure 1. Structure of d

‐ Limonene

The insecticidal mode of action of limonene is believed to be similar to pyrethrum

‐ by affecting

the sensory nerves of the peripheral nervous system (not a cholinesterase inhibitor) 4

. As an

herbicide, d

‐ limonene is a non

‐ systemic, contact herbicide that strips the waxy rind or cuticle

from plants, causing the plant to desiccate, resulting in the death of the plant 5

.

The major route of dissipation for d

‐ limonene is volatilization. Other dissipation processes

include photodegradation in air, microbial

‐ mediated aerobic soil metabolism, sorption to soil

( e.g

., organic carbon), and transport in runoff water (IPCS, 1998 6 ). Functional groups of

limonene, cyclohexane ring and ethylene group, are not prone to hydrolysis. Microbial mediated

degradation is an important degradation pathway. Degradation rates in aerobic sewage sludge

have been reported to range from 41

‐ 98% degradation in 14 days to >93% degradation in 14

days. Biotic degradation of limonene has been observed with some specific microorganisms.

These studies were not designed to determine the biodegradation rates of limonene, but

suggested that limonene biodegradation (biodegradability in aerobic aqueous medium, OECD,

1992 7 ) was occurring as the biochemical oxygen demand ranged from 41 to 98% in 14 days

(IPCS, 1998). Because aerobic metabolism studies have not been submitted for d‐ limonene,

published aerobic biodegradation studies were used to estimate a first order biotransformation

rate (d

‐ 1 ); for a half

‐ life of 38.5 days 8,9 ( Appendix 2 ). Under anaerobic conditions, d

‐ limonene

appears to be persistent. In the atmosphere d‐ limonene will photo

‐ chemically degrade

producing hydroxyl and nitrate radicals and ozone.

B. Overview of Pesticide Use and Usage

The production of d‐ limonene and use in flavorings, fragrances, cosmetics, as a solvent, a

wetting agent, and in the manufacture of resins may result in its release to the environment

through various waste streams. d‐ limonene is also found in many oils and fruits and is emitted to

the environment from plants and the combustion of wood. d‐ limonene is used as both an active

5 Ware, G.W. and Whitacre, D.M. 2004. The Pesticide Book. Pg. 66

5 Stephen O. Duke, Joanne G. Romagni, Franck E. Dayan 2000. Natural products as sources for new mechanisms of herbicidal action. Crop

Protection 19 (2000) 583

‐ 589.

6 IPCS, 1998. http://www.inchem.org/documen ts/cicads/cicads/cicad05.htm

7 OCED, 1992. http://www.oecd.org/chemicalsafety/risk

‐ assessment/1948209.pdf

8 Misra, G. and Pavlostathis, S.G., 1997. Biodegradation of monoterpenes in liquid and soil

‐ slurry systems. Appl. Microbiol. Biotech. 47:572

‐ 577.

9 Rifai, H.S. and C.J. Newell. 1998. Estimating First

‐ Order Decay Rates for BTEX Using Data from 115 Sites, in Proceedings of the 1998 NGWA

Conference on Petroleum Hydrocarbons and Organic Chemicals in Ground Water: Prevention, Detection and Restoration, Nov. 11

‐ 13,

Houston, Texas, pp. 31

– 41, National Ground Water Association, Westerville, OH.6

and inert ingredient in pesticide formulations. d‐ limonene is used as an acaricide, herbicide,

insecticide, and insect repellent/feeding depressant. Formulations include an emulsifiable

concentrate, impregnated material, pressurized liquid, and a ready

‐ to

‐ use liquid. A summary of

use sites is shown in Table 1

.

Table 1. Summary of Use Sites Registered for d‐ lim onene

Use Sites Groups

Terrestrial Citrus fruits, cole crops, flavoring/spice crops, fruiting vegetables,

grapes, leafy vegetables, legume vegetables, pome fruits, root and

tuber vegetables, small fruits, tree nuts, Christmas trees; Nursery

stock; Ornamentals (plants, trees, turf); Outdoor buildings and

structures(perimeter); sidewalks, rights

‐ of

‐ ways/fencerows/hedgerows; Refuse/solid waste sites/Manure;

Recreational Areas; Sewage systems; Wood protection treatment

to bu ildings/products

Indoor Household/domestic dwellings

Commercial/institutional/industrial premises/vehicles

Dogs/ Cats; Pet living/sleeping quarters

Human body

‐ clothing while being worn

Wide area general indoor treatment (public health)

Wood protection treatment to buildings/products

Limonene is not applied aerially. It is applied using ground sprayers (ready

‐ to

‐ use containers,

hooded sprayers, pump sprayers, and pressurized containers), aerosol containers (cans),

impregnated strips, injection equipment, or manually with a sponge. There is a wide range of

limonene concentrations and application rates for the formulated products. Because many of

the uses are “spot” treatments or edge or boundary use, the application rates used in the

exposure models lead to uncertainty.

Many of the labels for d‐ limonene do not provide a complete application rate (e.g., the label may

say to spray for 10 seconds or only states a concentration in lb/gal without a finish spray

volume). Current models used by EFED to estimate exposure require application rates on a per

unit area basis ( e.g., lb a.i./A). Other label issues are the lack of a maximu m yearly (or seasonal)

rate, the number of applications per year, or the reapplication interval. Additionally, because of

the large range in rates, this assessment has focused on the labels with the highest application

rates.

The aquatic exposure assessment is focused on the Avenger TM AG Burndown Herbicide (EPA Reg.

No. 82052

‐ 4) and the Orange Guard Ornamental Plants Protection Concentrate (EPA Reg. No.

61887

‐ 3) products, both of which specify the application rates on a per area basis. With single

application rates as high as 34.6 lb a.i./A for the Avenger TM AG Burndown Herbicide and 55.2 lb

a.i./A for the insecticide Orange Guard Ornamental Plants Protection Concentrate, these

products provide an upper

‐ bound screen for aquatic exposures. The burndown herbicide

product can be applied to a variety of agricultural crops as a broadcast or spot treatment with

ground equipment such as a directed sprayer or hooded sprayer. When the application rate of7

34.6 lb a.i./A is used, the herbicide is applied as a spray over the target vegetation. The label

does not specify a maximum number of applications or a yearly application rate. However,

additional information was provided to clarify the intended use indicating a maximum of 12

applications with a 2

‐ day minimum re application interval 10

. Literature suggests that repeat

applications may be necessary for larger weeds. 11,12,13 The Orange Guard product is intended for

use as a foliar (insecticide) spray to protect ornamental plants and when factoring in the high

finished spray volumes, the rates are as high as 55.2 lb a.i./A (with up to six applications/yr at a

7

‐ day interval).

For the terrestrial exposure assessment, additional scenarios were selected to bound the

potential exposures to te rrestrial organisms. Thus, in addition to the scenarios discussed above,

the lower rates on the Orange Guard label (4.6 and 18.4 lb a.i./A) were also quantitatively

assessed. These additional scenarios also bracket the non

‐ broadcast labeled uses such as the

perimeter treatment, mound sprays and spot treatments with rates such as 0.454 lb a.i./sq ft

(19.79 lb /A for moss and algae control on lawns) and 0.2265 lb a.i./mound (assuming 40

mounds/A

= 9.06 lb a.i./A). While these “per acre” extrapolations are high, they are the values

that would be used in the TREX mode l to estimate the residues on feed items within the

spot/area treatment that the animal may be foraging.

Given the low toxicity of d

‐ limonene, the small scale applications (aerosol spray, crack and

crevice, etc.), were not quantitatively assessed in this assessment. Table 2 provides an overview

of the uses that are considered repres entative of the highest use patterns. The application rates

in bold were selected for exposure modeling. For a complete list of all d‐ limonene uses see

Appendix 1.

10 Correspondence from S. McIntosh to R. Wasem (April 11, 2014).

11 http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=6498

12 http://www.groworganic.com/avenger

‐ weed

‐ killer

‐ conc

‐ 32

‐ oz.html

13 http://avengerorganics.com/LinkClick.aspx ?fileticket=sWUA%2BS% 2BCs6g%3D&tabid=818Table2.OverviewofRepresentativeHighExposured‐limoneneUsesCrop/SiteProduct/Reg.numberTiming;App.TypeMethod/EquipmentMaximumSingleApplicationRate(lba.i./A)MaxRatePerYearlba.i./AMax.Num.Apps./YrMRI(d)CommentsOrnamentalplantsingreenhouses,nurseries,Christmastreeplantations,andlandscapes(residentialcommercial,industrial)OrangeGuard‐OrnamentalPlants(5.8%)Insecticide/Repellent61887‐3FoliarBroadcastGroundSprayer/Pumpsprayer/Handheld4.627.667Rateswereexpressedasdilutionof(1:4;0.092lba.i./galwater),or(1:6)withvariousfinishsprayvolumes.“rowcrops25‐50gal/A;vinecrops50‐200gal/A,treecrops100‐400gal/A,greenhouse100gal/10,000sqft,600galperA‐forestry”.18.4110.436.8220.840.1240.655.2331.2Ag.Crops:Brassicaveg;citrus;grapes;herbs;leafyveg;legumeveg;pomefruit;root&tuberveg;smallfruit;stonefruit;treenutsAvengerTMAGBurndownherbicide(55%)82052‐4aWeedpost‐emergence/burndownBroadcastandSpottreatmentGroundSprayer‐Directed/Hoodedsprayer34.6415.212b2bLabelstatesdonotexceed8.5gallonsofproductperacreperapplication(4.07lba.i./gal*8.5gal/A=34.60lba.i./A).Bordersarounddriveways,patios,sidewalks,maturetreesandornamentals,buildings,residentialgreenhouses,fencerows,flowerbedsAvengerWeedKillerConc.(70%)/RTU(17.5%)82052‐182052‐3Weedpost‐emergence/burndownPerimeter/SpotGroundSprayer1.28‐1.47lba.i./gal(dilution)51‐59lba.i./A*NS12b2b*Assumed40gallonsperAbecausethelabeldidnothaveafinishsprayvolumetocompletetherate.Needfurtherclarificationonlabeltoreduceuncertainty.Giventheuncertaintyandtheuseasperimeter/spottreatment,thisassessmentwillusethehighscenariosabovetoinformontheriskforthisuse.aLabelprovidessprayerrequirements:Donotusenozzlesornozzleconfigurationswhichproducefinedroplets(mist).Uselowdrift,lowpressurenozzlesandsprayhoodsmustoperateonthegroundorskimmingacrossgroundsurfacebTheminimumretreatmentintervalwasnotspecifiedonthelabelbuttheregistrantsuggestedevery2daysfordifficulttotreatweeds.9

Limonene Usage

National

‐ level pesticide usage data for d‐ limonene is not available. d

‐ limonene usage data has

been reported by the California Department of Pesticide Regulation Pesticide Use Reporting and

was summarized by USEPA’s Biological and Economic Analysis Division (BEAD) ( Table 3 ).

Table 3. Limonene Usage Data: California, 2001

‐ 2012

Year Pounds A.I. Applied

(Ag a & Non Ag b Applications) Cumulative Acres Treated

(Ag Only)

2001 40,703 34,695

2002 37,393 39,562

2003 28,072 48,939

2004 14,349 49,320

2005 45,877 62,359

2006 32,843 75,333

2007 68,949 79,012

2008 45,536 64,151

2009 56,495 55,465

2010 56,403 29,621

2011 14,460 10,025

2012 17,976 73,328

AVG 42,662 51,818

Source: California DPR, 2010, Summary of Pesticide Use Report Data, Use Trends of Biopesticide Pesticides:

http://www.cdpr.ca.gov/docs/pur/pur10rep/10sum.htm

C. Previous Ecological Risk Assessments and Evaluations

The ecological risk assessment for the Reregistration Eligibility Decision (RED), completed in

September 1994 (EPA 738

‐ R

‐ 94

‐ 034), was based on a limited number of environmental fate and

ecological toxicity studies. Exposure concentrations for the risk assessment were estimated using

simple screening level exposure mode ls and limited toxicity data. The risk assessment concluded

that minimal risk is anticipated for birds, mammals, and aquatic animals for the pesticidal uses of

limonene. EFED believed at that time that applications of limonene did not pose any undue risks

to endangered species. The 1994 assessment prepared for the RED did not include a terrestrial

or aquatic plant assessm ent because limonene was not registered as an herbicide at that time.

Additionally, several new uses have been registered (for example, the Burndown Herbicide

‐

Avenger TM AG) so the rates in this current assessment are substantially higher than previous

assessments. Additional ecological data for plants (terrestrial and aquatic) have also been

submitted and considered in this assessment along with additional mammal data that was cited

in the 2007 TRED (the previous assessment was based on a non

‐ definitive acute oral endpoint

and did not consider any chronic data).10

Although, no additional environmental fate data has been submitted, published literature was

reviewed and used to confirm previously used values or change or add an additional value ( e.g

., degradation or dissipation process), if appropriate. The Food and Drug Administration (FDA)

considers limonene to be Generally Recognized as Safe (GRAS) as a food additive when used as a

synthetic flavoring substance and adjuvant (21 CFR §182.60).

III. Risk Hypothesis and Conceptual Model

A. Measures to Evaluate Risk Hypotheses

In the case of d

‐ limonene, measures of exposure are based on terrestrial and aquatic exposure

models 14 that estimated environmental concentrations (EEC) of d

‐ limonene using maximum

labeled application rates. The T

‐ REX model (version 1.5.2) was used to produce terrestrial EECs

on wildlife food items. The STIR model was not used in this assessment because inhalation

toxicity data were not available. The TerrPlant and AgDRIFT models are used to estimate

exposure to nontarget plants. The Surface Water Concentration Calculator (SWCC 15 ; version

1.106) (see Section III A. 1) and the linked PRZM/EXAMS with PE5 16 are used to produce aquatic

EECs and drinking water EDWCs. Because the SWCC currently does not include volatilization

from soil, whereas PRZM does, aquatic exposure (EECs) concentrations were refined with

PRZM/EXAMS for the scenarios that resulted in the highest concentrations estimated by SWCC.

Both consider volatilization from water. Limited monitoring data for air and water are available,

but these data were collected in studies that were not specifically targeted for the pesticidal uses

of limonene.

Measures of effect are obtained from a suite of studies conducted with a limited number of

surrogate species. The lowest toxicity endpoints for the most sensitive surrogate test species are

used to estimate treatment

‐ related effects on growth, reproduction and/or survival.

B. Risk Hypothesis

For this assessment, the risk to non

‐ target organisms is based on potential effects from the

application of d‐ limonene to the environment. The Agency presumes the following risk

hypothesis for this screening level assessment:

Based o n mode of action, the proposed use patterns, and the sen sitivity of non‐target

aquatic and terrestrial species, the proposed uses of d‐ limonene have the potential to

reduce survival, reproduction, and/or growth in terrestrial and aquatic animals and plants

through direct application, spray drift and/or runoff.

14 http://www.epa.gov/pesticid es/science/models_pg.htm

15 http://www.epa.gov/oppefed1/m odels/water/index.htm#swcc

16 PE5 suite of models (PE5 v5.0, PRZM v3.12.2, EXAMS v2.98.04.06) and scenarios11

In order for a chemical to pose an ecological risk, it must reach non

‐ target organisms at

concentrations found to cause adverse effects. The assessment of ecological exposure pathways

in this assessment includes an examination of the source and potential migration pathways to d‐

limonene exposure, and the determination of potential adverse effects on non

‐ target species.

C

. Con ceptual Model

Application methods for d‐ limonene involve foliar spray via ground equipment. Ecological

receptors that may potentially be exposed to d‐ limonene include terrestrial and semi

‐ aquatic

wildlife ( i.e.

, mammals, birds, amphibians, terrestrial invertebrates, and reptiles) and plants. In

addition, aquatic receptors ( e.g

., freshwater and estuarine/marine fish and invertebrates,

amphibians, and plants) may also be exposed as a result of po tential movement of d‐ limonene

via spray drift and/or runoff from the site of application to aquatic environments. Exposure to

terrestrial animals is based primarily on dietary consumption of foliar residues while aquatic

assessments assume that all major po tential routes of direct exposure are accounted for. The

major transport pathway for d

‐ limonene is volatilization.

IV. Measures of Exposure

Limonene functions as an acaricide, herbicide (including moss and algae pests in terrestrial

environments), and also as an insecticide/repellent. The insecticide/repellent uses tend to be

more of a spot treatmen t in nature, whereas the herbicide uses can include spot treatment,

perimeter/border treatment, or treatments to a field (although the applications are generally

directed applications rather than full

‐ acre broadcast treatments).

The environmental fate data for this assessment was generally obtained from open literature

data such as the World Health Organization (IPCS, 1998 17 ) and Limonene (CICAD#5, 1998 18 ),

TOXNET (2006 19 ) and USEPA High Production Volume Information System (HPVIS), 2014 20 and

are essentially the same as the previous assessment conducted for the RED. These sources

generally report the same information because they tend to cross

‐ reference each other. Data

values from these sources were generally selected to be consistent with the RED (1994) and the

USEPA OPPT Screening Level Hazard Characterization of Mono terpene Hydrocarbon

Category. 21,22 Additional information was included when available. Chemical identification and

physical

‐ chemical properties of limonene are shown in Table 4

. When available, experimental

physical

‐ chemical properties are reported. Exposure concentrations were estimated using simple

screening level exposure models.

17 IPCS, 1998. http://www.inchem.org/documen ts/cicads/cicads/cicad05.htm

18 CICAD#5, 1998. http://whqlibdoc.who.int/publications/1998/9241530057.pdf

19 TOXNET, 2006. http://toxnet.nlm.nih.gov/cgi

‐ bin/sis/search/a?dbs+h sdb:@term+@DOCNO+1809

20 http://www.epa.gov/chemrtk/hpvis/hazch ar/Category%20Monoterpenes_Sept2009.pdf

21 http://www.epa.gov/hpvis/hazchar/Ca tegory%20Monoterpenes_Sept2009.pdf

22 http://ofmpub.epa.gov/oppthpv/quicksearch.display?pChem=10150912

A. Environmental Fate and Modeling Input Parameters

Physical/Chemical and Envi ronmental Fate Properties

The physical/chemical properties and environmental fate properties of d

‐ limonene are listed in

Table 4.

Table 4. Identity and Physical

‐ Chemical Properties of d‐ limonene

Type of Information Information Source

Chemical name IUPAC: ( R )

‐ 4

‐ isopropenyl

‐ 1

‐ methylcyclohexene

or p

‐ mentha

‐ 1,8

‐ diene

CAS (4 R )

‐ 1

‐ methyl

‐ 4

‐ (1

‐ methylethenyl)cyclohexene http://www.alanwood.net/pesticides/d

‐

limonene.html

Pesticide type Acaricide, herbicide, insecticide,

repellent/feeding depressant Pesticide Labels

CAS Reg. No. d

‐ limonene: 5989

‐ 27

‐ 5

Racemate: 7705

‐ 14

‐ 8

l

‐ Limonene: 5989

‐ 54

‐ 8 http://www.alanwood.net/pesticides/d

‐

limonene.html

Empirical Formula C 10 H 16 http://www.alanwood.net/pesticides/d

‐

limonene.html

Smiles String C(=CCC(C(=C)C)C1)(C1)C

Molecular mass (g/mol) 136.23 CICAD#5, 1998; IPCS, 1998

Physical State Liquid (colorless) CICAD#5, 1998; IPCS, 1998

Specific gravity 0.8411 g/cm 3 (7.4 lb/gallon) CICAD#5, 1998; IPCS, 1998

Melting point  ̊ C

‐ 74.35 CICAD#5, 1998; IPCS, 1998

HPVIS, 2014

Boiling point  ̊ C 175.5

‐ 178.6 @ 760 mm Hg

176 @ 760 mm Hg CICAD#5, 1998; WHO, 1998

HPVIS, 2014 a

Solubility in water (mg/L) 13.8 @ 25  ̊ C Massaldi and King, 1973 23

. [ J. Chem. Eng. Data

, 1973, 18: 393

‐ 397]

CICAD #5, 1998; IPCS, 1998

HPVIS, 2014

Vapor pressure 1 mm Hg @ 20  ̊ C

2 mm Hg @ 20  ̊ C

3 mm Hg @ 14.4 °C

1.43 mm Hg @ 20  ̊ C (measured)

1.2 mm Hg @ 20  ̊ C

1.59 mm Hg @ 20  ̊ C MRID 93136002

MRID #46511103 (Product Chemistry)

EPA HQ

‐ OPP

‐ 2004

‐ 0335

‐ 0 03.pdf

IPCS, 19 98; HPVIS, 2014

HPVIS, 2014

FFHPVC Terpene Consortium b,

Henry’s Law Constant

(calculated) 1.3 x 10

‐ 2 atm

‐ m 3 /mole @ 20  ̊ C [1

mm Hg]

1.8 x 10

‐ 2 atm

‐ m 3 /mole @ 20  ̊ C [1.43

mm Hg] (Solubility

– 13.8 mg/L)

Copolovici and Niiements, 2005

23 http://pubs.acs.org/doi/pdf/10.1021/je60059a02413

Type of Information Information Source

2.6 x 10

‐ 2 atm

‐ m 3 /mole @ 20  ̊ C [2

mm Hg]

2.8 x 10

‐ 2 atm

‐ m 3 /mole @ 20  ̊ C

2.8 x 10

‐ 2 atm

‐ m 3 /mole @ 25  ̊ C

3.2 x 10

‐ 2 atm

‐ m 3 /mole SRC as cited by TOXNET, 2006

Enthalpy of Vaporization kj/mole (kcal/mole)

37.8 ( 9.03) to 49.9 (11.93) Chickos J.S. and Acree, W.E. 2003..J. Phys.

Chem. Ref. Data. 32:519

‐ 877.

http://www.chemicaldictionary.org/dic/D/D

‐ Limonene_332.html

Clará et al. 2009. J. Chem. Eng. Data 54:1087

‐

1090.

Copolovici and Niiements, 2005

Organic Carbon Partition

Coefficient

(K

oc ) (mL/g

oc ) 1,300

1,030 to 4,780 (estimated)

1,260 (estimated) TOXNET, 2006; CICAD#5, 1998;

IPCS, 1998; 1030

HPVIS, 2014

Log K

ow ( n

‐ octanol/water

partition coefficient) 4.88; 4.83 @ 25  ̊ C (calculated)

4.23 @ 20  ̊ C (measured)

4.50 @ 25oC CICAD#5, 1998; IPCS, 1998; HPVIS, 2014.

Copolovici and Niiements, 2005

Log K

o

‐ air (octanol

‐ air

partition coefficient) 4.26 (estimated; EPISuite)

pK

a /pK b Not applicable

‐

Bioconcentration Factor

(BCF) 246 to 262 (estimated from log Kow

4.23)

660 (estimate from log Kow 4.57) CICAD#5

TOXNET, 2006

Aqueous Photolysis Half

‐

life [t 1⁄2 ](days) 0.037 days (reported as 0.884 hours) HPVIS, 2014

FFHPVC Terpene Consortium b,c

Estimated, AOPWIN, EPI Suite 2000

Foliar Dissipation Rate Estimated 2.79 to 4.67 ppm/hour MRID 47548301

a HPVIS, 2014. High Volume Information System:

http://www.epa.gov/chemrtk/hpvis/hazcha r/Category%20Monoterpenes_Sept2009.pdf

b http://ofmpub.epa.gov/oppthpv/document_api.download?FILE=Summaries%20sn133.pdf

c http://www.epa.gov/hpv/pubs/ summaries/monoterp/c13756rt.pdf

Environmental Fate/Exposure Summary

Much of the physicochemical and environmental fate values for d‐ limonene are based upon

values reported in literature and were estimated by models such as EPI (Estimate Program

Interface) Suite 24 and were obtained from a variety of published sources (CICAD #5, 1998;

TOXNET, 2006; HPVIS, 2014; SRC, 2014; IPCS, 1998). While there is variability in the values

reported in literature, the conclusion derived in this assessment would be the same (low

solubility, volatile, low mobility in soil, photodegradable in air, and biodegradable under aerobic

conditions) (Clará et al., 2009; Copo lovici and Niinemets, 2005). Also, some of the measured data

may actually be the d/l‐ limonene (racemic mixture) rather than d

‐ enantiomer ( i.e

., d‐ limonene).

Where values are available both for the d‐ and d/l‐ limonene, they are generally similar in order

24 EPI Suite,2014 http://www.epa.gov/opptintr/exposure/pubs/episuite.htm14

of magnitude. The routes of dissipation for d

‐ limonene include volatilization, photodegradation

in air, microbial

‐ mediated aerobic soil metabolism, and binding to soil/sediment (IPCS, 1998;

TOXNET, 2006).

Limonene is stable to hydrolysis. Microbial mediated degradation is an important degradation

pathway as biotic degradation of limonene has been observed with some microorganisms in

some pure microbial cultures 25

. Degradation in aerobic sewage sludge has been reported to

range from 41

‐ 98% degradation in 14 days. These studies were not designed to determine the

biodegradation rates of limonene, but suggested that limonene biodegradation (biodegradability

in aerobic aqueous medium, OECD, 1992 26 ) was occurring as the biochemical oxygen demand

ranged from 41 to 98% in 14 days. Because aerobic metabolism studies have not been submitted

for d‐ limonene, published aerobic biodegradation studies were used to estimate a first order

biotransformation rate for the d‐ limonene; resulting in a half

‐ life of 38.5 days 27,28 ( Appendix 2 ).

Under anaerobic conditions, d‐ limonene appears to be persistent.

In the atmosphere, volatilized limonene undergoes rapid bi

‐ molecular gas

‐ phase reactions with

ozone, nitrate radicals, and photochemically generated hydroxyl radicals. Volatilization half

‐ lives

from water were estimated to range from 1 hour to 5 days, for a river and a lake model,

respectively (TOXNET, 2006). Photodegradation in air of d‐ limonene is an important degradation

pathway in the atmosphere. Degradation mechanisms have been associated with hydroxyl

radicals (t 1/2 =0.32 to 2 hours), ozone (t 1/2 =0.18 to 2.6 hours), and nitrite radicals (t 1/2 =0.08 to

0.015 hours) (TOXNET, 2006). Photodegradation products in air are: hydroxyl radical degradation

products including 4

‐ acetyl

‐ 1

‐ methylcyclohexane, a ketoaldehyde, formaldehyde, 3

‐ oxobutanal,

glyoxal, and C10 dicarbonyl; ozonolysis degradation products including

bis(hydroxymethyl)peroxide, hydrogen peroxide; and nitrite radical degradation products include

formaldehyde, acetaldehyde, formic acid, acetone, and prooxyacetyl nitrate.

A study [MRID 47648301] was submitted for QRD 400/QR D 416 for a residue trials for mustard

greens. QRD 400 (total 18.5% a.i.) and QRD 416 (total 17.43% a.i.) contain a mixture of 3 active

ingredients terpenes α‐ terpinene, ρ‐ cymene, and d‐ limonene. The two products were applied to

mustard green foliage at a rate of 2.6 and 2.4 lb a.i./A for QRD 400 and QRD 416, respectively.

Leaves were harvested at 0

‐ , 1

‐ , and 4

‐ hours. d‐ limonene levels generally dropped below the

limit of quantification (LOQ=0.05 ppm) at 1

‐ hour. Although, a half

‐ life could not be determined,

the rate of decline for d‐ limonene ranged from 2.8 to 4.67

‐ hr

. Adjusting the 2.4 or 2.6 lb a.i./A to

the maximum rate for d

‐ limonene (34.6 lb a.i./A), the time required for the d‐ limonene

concentrations to drop below the LOQ ranged between 3 and 15 hours ( Table 4 ).

25 Amaral, J.A., Keins, A., Richards, S.R., and Knowles, R. 1998. Effect of Selected Monoterpenes on Methane Oxidation,

Denitrification, and Aerobic Metabolism by Bacteria in Pure Culture. Applied and Environmental Microbiology, Vol 64(2), pp

520

‐ 525.

26 OCED, 1992. http://www.oecd.org/chemicalsafety/risk

‐ assessment/1948209.pdf

27 Misra and Pavlostathis. 1997. Appl. Microbiol. Biotechnol. 47:572

‐ 577.

28 Rifai and Newell, 1998. https://info.ngwa.org/GWOL/pdf/982664575.PDF15

The estimates of soil organic carbon partitioning coefficient (K

oc ) for d‐ limonene ranged between

1,030 and 4,780 mL/g

oc (SRC, 2014; CICAD#5, 1998, WHO, 1998). Based on the FOA mobility

classification, d‐ limonene is expected to be slightly mobile in soil 29

. It would tend to bind to

eroded soil and be transported in runoff water. However, the high vapor pressure (1 to 3 mm

Hg) and calculated Henry’s Law Constants ranged between 1.3 x 10

‐ 2 and 3.2 x 10

‐ 2 atm

‐

m 3 /mole, depending upon the vapor pressure value and solubility (7.54 to 13.8 mg/L), indicate

that limonene will readily volatilize from soil and water ( Table 4 ). However, this dissipation

process competes with binding.

The estimated log octanol

‐ water partition coefficients (K

ow s) range from 4.23 to 4.83 indicates

potential bioaccumulation. However, the bioconcentration factor, calculated on the basis of

water solubility and the log octanol/water partition coefficient, ranged 246 to 262 suggesting

that limonene is not expected to bioaccumulate in fish and other aquatic organisms. TOXNET

(2006) gives an estimated BCF value of 660. A log Kow between 4 and 8, would typically trigger

use of the KABAM model to determine if there are food chain concerns for birds and mammals

from consum ing aquatic organisms with accumulated residues, however, because of the low BCF

values, the high Henry’s Law Constant showing high volatility from water, and low/non

‐ definitive

toxicity for birds and mammals, this analysis was not conducted.

Monitoring Data Detections in Environmental Media

Limonene residues have been detected in rural, urban, suburban, and forest areas in the U.S.

and in other countries. These residues have been detected in air, surface water, ground water,

seawater, wastewater, ice, soils, and in solid waste composting facilities. Levels of limonene are

varied, but the limited data do not allow for a correlation with usage or geographical region.

The National Water Quality Assessment Program (NAWQA, 2014) database for d

‐ limonene

reports 481 samples collected in ambient surface of water, 602 groundwater samples, and 296

treated water supplies. The limit of detection appears to rang e from 0.013 to 0.5 μg/L). The

maximum concentration was 1.2, 0.072 and 0.157 μ g/L, in surface water, groundwater, and

treated water supplies, respectively. These monitoring studies were not targeted and many were

conducted prior to the registration of Avenger TM Burndown pesticide (EPA. Reg No. 82052

‐ 4).

The CICID#5 (1998) and TOXNET (2006) reported ( Table 5 ) detections observed in a number of

media from other studies. The detections of limonene (or d‐ limonene) in these monitoring

studies may reflect sources other than pesticidal use ( i.e

., sewage treatment).

29 USEPA. 2006. Standard Soil Mobility Classification Guidance. Memorandum From S. Bradbury to Environmental Fate and

Effects Division. April 21, 2006. Environmental Fate and Effects Division. Office of Pesticide Programs. United States

Environmental Protection Agency.16

Table 5. Concentrations of Limonene (or d

‐ limonene) observed in monitoring studies collected

from various media.

Medium Concentration Source

Outdoor Air 0.036 to 32 μg/m 3 CICAD#5, 1998

Lake Water 0.47 to 84 ng/L CICAD#5, 1998

Drinking Water Max. 30 ng/L (5 of 14 samples)

Max. 1.87 x 10 5 ng/L (1 of 182 samples CICAD#5, 1998

Estuary 25 to 633 ng/L CICAD#5, 1998

River Water 590 to 1,600 ng/L CICAD#5, 1998

Sea Water 2 to 40 ng/L CICAD#5, 1998

Ground Water (sewage contaminated) 1,000 to 130,000 ng/L TOXNET, 2006

Waste Water, Influent, sewage treatment plant Non

‐ detect to 220,000 ng/L CICAD#5, 1998

Sediment 105 to 807 ng/kg CICAD#5, 1998

Ice 4 to 15 ng/L CICAD#5, 1998

Surface Water 0.013 to 1.2 * μg/L (17 of 481) NAWQA, 2014 30

Bottom Material 15.4 to 111.1 * μg/kg (6 0f 35) NAWQA, 2014

Groundwater 0.016 and 0.072 * μg/L (2 of 602) NAWQA, 2014

Treated Water Supply 0.028 to 0.157 μg/L (4 of 296) NAWQA, 2014

* Concentrations are estimated.

Ecological Effects Characterization

There is a limited toxicity data set for d‐ limonene. Tables 6 and 7 summarize the available data

for the aquatic and terrestrial taxonomic groups, respectively. The tables provide a preliminary

overview of the potential acute toxicity of d‐ limonene by providing the acute toxicity

classifications.

Aquatic Organisms

On an acute exposure basis, d‐ limonen e is classified as “slightly toxic” to freshwater fish and

invertebrates. Data are not available to characterize the effects to aquatic organisms on a

chronic exposure basis, or for estuarine/marine animals on an acute basis. For aquatic plants,

blue green algae (Anabaena flos‐aquae ) was the most sensitive non

‐ vascular plant with

reductions in yield at all test concentrations [blue green algae; EC 50 = 9.353 mg a.i./L and NOAEC

<3.125 mg a.i./L], thus, the EC 05 (1.731 mg a.i./L) will be used as a proxy for the NOAEC. For non

‐

vascular plants, the EC 50 and NOAEC were 29.65 and 3.125 mg a.i./L, respectively, based on

reductions in frond yield for duckweed ( Lemna gibba ).

30 http://cida.usgs.gov/nawqa_queries_public/17

Table 6. Summary of Aquatic Toxicity Studies for d‐ Limonene

Taxonomic

Group Study

Type Surrogate

Species

and

Test Material Toxicity Value MRID and

Classification Acute

Toxicity

Classification

Freshwater

fish Acute Rainbow trout

(Oncorhynchus

mykiss) LC 50 = 80 mg a.i./L b 00146085

(Acceptable) Slightly toxic

Chronic No Data

Freshwater

invertebrates Acute Water flea

(Daphnia

magna) EC 50 = 39 mg a.i./L 00146085

(Acceptable) Slightly toxic

Chronic No Data

Estuarine/

marine fish

and

invertebrates No Data

Aquatic

plants and

algae Non

‐

vascular Blue

‐ green

algae a

(Anabaena

flos‐aquae) EC 50 = 9.353 mg a.i./L (nominal)

(95% C.I.: 7.4 to 11.8)

NOAEC = <3.125 mg a.i./L

EC 05 =1.731 mg a.i./L

Based on reductions in yield 49044004

(Supplemental

‐

quantitative) N/A

Vascular Duckweed

( Lemna gibba ) EC 50 =29.65 mg a.i./L (nominal)

(95% C.I.: 19.84 to 44.32 )

NOAEC: 3.125 mg a.i./L

Based on reductions in frond yield 49044001

(Supplemental

‐

quantitative) N/A

a For non

‐ vascular plants (e.g., algae, diatom), four species were tested and the values from the most sensitive test species

are reported.

b Exceeds the solubility according to the Fate Section

‐ DER does not mention any precipitate

Terrestrial Organisms

Data are not available to assess the toxicity of d‐ limonene to birds on an acute oral basis. On a

sub

‐ acute/dietary exposure basis, d‐ limonene is classified as “practically non

‐ toxic” to birds

based on a LC 50 of >5,600 mg a.i./kg diet and a lack of sublethal effects reported for the

Bobwhite quail (Colinus virginianus ). Data are not available to assess the risk on a chronic

exposure basis. For mammals, d‐ limonene is classified as “practically non

‐ toxic” on an acute

exposure basis. On a chronic exposure basis, a 2

‐ generation reproductive study was not available

so the NOAEL for the rat (250 mg a.i./kg/day) was based on reductions in body weight gain at18

500 mg a.i./kg/day treatment level in the available developmental toxicity study. Data are not

available to assess the toxicity of d

‐ limonene exposure via inhalation.

For terrestrial invertebrates, there are no toxicity studies available to assess the risk to terrestrial

invertebrates. Given that d‐ limonene is registered as an acaricide/insecticide, the acute contact

toxicity to the honey bee ( Apis mellifer a ) is a data gap.

For terrestrial plants, there were no effects reported in the available seedling emergence study,

thus, the NOAEC is ≥ 265

‐ 345 lb a.i./A (MRID 49044005). In the vegetative vigor toxicity study,

there were effects reported at all treatment levels so the EC 05 was used as a proxy for the NOAEC

(Monocots

‐ EC 25 : 2.83 lb a.i./A; EC 05 = 0.19 lb a.i./A

‐ Dicots EC 25 =7.09 lb a.i./A; EC 05 = 1.31 lb a.i./A)

which was based on reductions in dry weight (MRID 49098302).

Table 7. Summary of the Terrestrial Toxicity Studies for d‐ Limonene

Taxonomic

Group Study Type

and test

material Surrogate Species Toxicity Values (all units in

terms of measured a.i.) MRID and

Classification Acute

Toxicity

Classifica

‐

tion

Mammals Acute Oral a

‐

Technical Mouse

(Mus musculus) 5600 mg/kg

‐ bw (M)

TRED, 2005 Practically

Non

‐ toxic 6600 mg/kg

‐ bw (F)

Laboratory rat

( Rattus norvegicus ) 4400 mg/kg

‐ bw (M)

5100 mg/kg

‐ bw (F)

Chronic a,b

‐

Technical Laboratory rat

( Rattus norvegicus ) NOAEL: 250 mg/kg/day

LOAEL: Small reductions

in maternal body weight

gain were observed at

500 mg/kg. b RED, 1994 N/A

Birds Acute

‐ Oral No Data

Subacute

Dietary

(Technical) Bobwhite quail

(Colinus virginianus) LC 50 = >5,600 mg /kg

‐ bw

No sublethal effects

reported MRID 00146988

(Acceptable)

Terrestrial

Invertebrates Acute

(contact/oral)

No Data19

Terrestrial

Plants Vegetative

Vigor Dicot

‐ cabbage EC 25 : 7.09 lb a.i./A

NOAEC: <7 lb a.i./A based

on reductions in dry

weight

EC 05 = 1.31 lb a.i./A

49098302

(Acceptable) N/A

Monocot

‐ corn EC 25 : 2.83 lb a.i./A

NOAEC: <8 lb a.i./A,

based on reductions in

dry weight

EC 05 =0.19 lb a.i./A

Seedling

Emergence Dicot EC 25: Not determined

NOAEC ≥ 265

‐ 345 lb a.i./A 49044005

(Supplemental

‐

Qualitative) N/A

Monocot

a Study reviewed by HED

b Reviewer’s Note: Slight but statistically significant and dose

‐ dependent increases in the number of liters and 10

fetuses with 14 ribs instead of 13 were observed at 500 and 1000 mg/kg/day. These effects are considered variations

in skeletal formation, were not accompanied by other effects, are secondary to maternal toxicity and do not re present

a concern for de velopmental toxicity of limonene.

V. ANALYSIS

A. Exposure Modeling

The input parameters used in this aquatic and terrestrial modeling assessment are selected from

the environmental fate data available in open literature or estimated (i.e., EPI

‐ Suite). Input

parameters were generally in accordance with US EPA

‐ OPP EFED water model parameter

selection guidelines, Guidance for Selecting Input Parameters in Modeling the Environmental

Fate and Transport of Pesticides 31 or with “best professional judgment”. Detailed information

about the models, selection of input parameters and scenarios can be obtained from

http://www.epa.gov/oppefed1/models/water/index.htm.

Aquatic Modeling

Potential aquatic exposures were initially estimated using the Surface Water Concentration

Calculator (SWCC; Version 1.106, 05/22/2014) and the Pesticide Root Zone Model (PRZM,

version 3.12.3, June 2006) and Exposure Analysis Modeling System (EXAMS; version 2.98.04.06,

April 2005), linked with the PE5.pl input shell (November 2006). PRZM/EXAMS was used to refine

the surface water exposure concentrations for aquatic exposure for the ecological as sessment.

Both models simulate the fate and transport of pesticides on the agricultural field (PRZM) and

the fate and resulting daily concentrations of pesticides that reach an adjacent water body

31 Parameters are selected as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of

Pesticides; Version 2.1, October 22, 2009.20

through runoff, erosion, and spray drift (EXAMS). Both models consider volatilization from a

surface water body, but currently only PRZM has the capacity to consider volatilization from the

soil. Neither model addresses the volatilization from a plant surface (i.e., target plant).

Additionally, both models were developed for “field” crops, therefore, considerable uncertainty

exists when scaling down from a per acre to per square foot basis.

Simulations are based on crop

‐ specific scenarios developed to represent environmental

conditions at sites with a generally high runoff vulnerability. Aquatic ecological exposure is

estimated using the “standard pond” scenario based on a 10

‐ ha field bordering a 1

‐ ha water

body, 2

‐ m deep (20,000 m 3 ) with no outlet. Weather and agricultural practices are simulated for

30 years so that the 10

‐ year exceedance probability at the site can be estimated. The simulation

was generated using 30 years of meteorological data, encompassing the years from 1961 to

1990.

Aquatic Model Inputs

The method of chemical application for both mode ls is assumed to be ground spray (ground in

SWCC) and (CAM

= 1 for PRZM/EXAMS). d‐ limonene is (generally) applied as a foliar spray to

weeds; both models assume the pesticide is applied to soil or foliarily to the crop by considering

crop emergence and harvest dates and not the target weeds. Pesticide application management

inputs and spray drift parameters are summariz ed in Table 8

. Ground spray methods were

assumed for both the preemergence and postemergence applications defined by each scenario.

For the non

‐ crop uses (i.e., spot treatment, boundary treatments, wood treatment), the

application rates are assumed to be less than the crop uses (on a per acre basis).

Table 8. PRZM/ EXAMS Input Parameters for d‐ Limonene

Input Parameter Value Reference/Discussion

#/Maximum Appl. Rate/Interval

(#/lb a.i./A; reapply interval; days) 12 app @ 34.6; 2 days

6 app @ 55.2; 7 days 8.5 gallons product/A (label)

Molecular Weight (g/mole) 136.23 Calculated

Henry’s Law Constant

(atm

‐ m 3 /mol) 2.6 x 10

‐ 2 Calculated

Vapor Pressure @ 20oC (torr) 2 MRID 46511103

Enthalpy of Vaporization

(kj/mole (kcal/mole))

REQUIRED for PRZM to include

volatilization. 37.8 ( 9.03) to 49.9

(11.93)

10.48

= numerical

mid

‐ point between

low and high values. Chickos J.S. and Acree, W.E. 2003.

http://www.chemicaldictionary.org/dic/D/D

‐ Limonene_332.html

Clara et al. 2009. J. Chem. Eng. Data 54:1087

‐ 1090.

Solubility (mg/L) @ 25oC 13.8 Massaldi and King, 1973

Aqueous Photolysis Half

‐ life

[t 1⁄2 ](days) a Stable No data

Hydrolysis [t 1⁄2 ] @ pH 7 (days) Stable

‐

Aerobic Soil Half

‐ life [t 1⁄2 ] (days) 33.53

[estimated] Misra and Pavlostathis. 1997. Appl. Microbiol.

Biotechnol. 47:572

‐ 577.

Rifai and Newell, 1998.

https://info.ngwa.org/GWOL/pdf/982664575.PDF21

Input Parameter Value Reference/Discussion

Did not multiple single value times 3 a

.

Aerobic Aquatic Half

‐ life [t 1⁄2 ] (days) 67.1 Estimated 2 times the aerobic soil metabolism

half

‐ life.

Anaerobic Aquatic Half

‐ life [t 1⁄2 ]

(days) Stable No data

Organic Carbon Partition

Coefficient (K

oc ) (mL/g

oc ) 1,300 Estimated range 1,030 to 4,780 CICAD#5, 1998;

IPCS, 1998; 1,300 a specific value given in TOXNET,

2006

Diffusion coefficient of pesticide in

air (DAIR) (cm 2 /day) 4,300 PRZM Manual

Pesticide Application

Maximum Application Rates:

(EPA Reg. #; 82052

‐ 4)

(EPA Reg. #; 61887

‐ 3) Labels

12 applications @ 34.6 lb a.i/A, 2 day reapplication interval

6 applications @ 55.2 lb a.i./A, 7 day reapplication interval

Chemical Application Method

Model

PRZM/EXAMS (CAM)

SWCC Ground Spray

= Soil applied CAM=1

= Ground Defined by model

Application Efficiency

(PRZM/EXAMS/SWCC) 0.99 EFED Guidance

Drop Size Distribution

(PRZM/EXAMS/SWCC)

Very Fine to Fine

[EPA Reg No. 61887

‐ 3]

Fine to Medium/Coarse

[EPA Reg. No. 82052

‐ 4] Boom Height:

Low

High

Low

High Ground Spray

Ecological Spray Drift Fraction

0.027

0.062

0.011

0.017

a Although EFED guidance generally recommends multiplying single soil half

‐ life measurements by 3 in order to account for

variability, a 3x factor was not applied to the aerobic soil metabolism half

‐ life because the biodegradability test suggested rapid

degradation. Little difference was observed in the estimated EECs when the aerobic metabolism value was multiplied by 3.

Several uncertainties exist in the environmental fate input parameters in large part because

many are estimates rather than measured. The aerobic soil metabolism half

‐ life value estimated

from the biodegradation rates of several monoterpenes including limonene in liquid and soil

‐ slurry systems and the aerobic aquatic metabolism half

‐ life was estimated from the aerobic soil

metabolism value. Greater uncertainty is probably due to limitations in the volatilization routines

in the models. Another major uncertainty is the use rates and number of applications of d

‐

limonene.

Aquatic Modeling Results

The initial EECs ( Appendix 3, Table 1 ) for aquatic exposure were estimated, without volatilization,

for a number of uses using the SWCC

. Aquatic RQs for aquatic invertebrates would exceed the

LOC of 0.05 for some scenarios. The scenarios that resulted in the highest concentrations with

the SWCC were rerun using PRZM/EXAMS, with PE5, with volatilization included in PRZM. The

aquatic exposure EECs estimated using PRZM/EXAMS are presented in Table 9

. d‐ limonene

concentrations in surface water are presented for the PRZM/EXAMS with and without the

volatilization routine turned on in PRZM. Volatilization reduced the peak aquatic EECs from 8022

to 95% depending upon the scenario. The highest peak value across the different scenarios

(323.6 μg/L) was used for the exposure value in this assessment. Representative outputs from

the different models are presented in Appendix 4

.

Table 9. Surface Water: Aquatic Exposure: PRZM/EXAMS d‐ limonene estimated Peak, 96

‐ hour, 21

‐ day and 60

‐ day average concentrations in standard farm pond for maximum rates with and

without volatilization (in PRZM ).

Scenario

(1 st app: mn/day) Volatilization

with PRZM b Peak 96

‐ hr 21

‐ day 60

‐ day

μg/L

NC Sweet Potato n 2478 1737 732 340

(5/15) y 113.0 95.6 85.5 38.6

GA Pecan n 3542 2450 1045 464

(5/15) y 225.3 168.8 114.9 55.7

TN Nursery n 2179 1646 881 459

(3/16) y 217.7 177.1 116.9 57.8

NJ Nursery n 1659 1565 1389 784

(01/01) y 323.6 309.6 272.0 210.9

FL Strawberry n 2240 1625 583 244

(10/03) y 124.7 98.5 77.5 35.6

a Application rate: 12 application @ 34.6 lb a.i./A; 2 day interval.

b n is without volatilization and y is with volatilization in PRZM

‐ (volatilization is simulated in EXAMS for both)

Terrestrial Exposure Modeling

‐ Animals

For this assessment, the exposure scenario modeled for terrestrial animals is for a foliar spray via

ground equipment, which is representative of the post

‐ emergence/burndown herbicide uses as

well as the insecticide/repellent uses ( e.g., ornamentals, nurseries). The EEC values used for

terrestrial animal exposure are derived from the Kenaga nomograph, as modified by Fletcher et

al. (1994), bas ed on a large set of actual field residue data. The upper limit values from the

nomograph represent high end residue values from actual field measurements (Hoerger and

Kenaga, 1972). The Fletcher et al. (1994) modifications to the Kenaga nomograph are based on

measured field residues from 249 published research papers, including information on 118

species of plants, 121 pesticides, and 17 chemical classes.

Terrestrial exposure estimates (EECs) for avian and mammalian risk assessments were derived

using the T

‐ REX model (version 1.5.1) ( Tables 10

‐ 14 ) and were based on the products with the

highest application rates for the different use patterns ( Table 2 ). The default 35

‐ day foliar half

‐

life value was used for modeling EECs on terrestrial food items, however, see the Risk

Description section for further discussion regarding a shorter half

‐ life value. A complete

description of the input parameters and output is contained in APPEN DIX 5

.23

Table 10. EECs on Potential Food Items Following Label

‐ Specified Applications of d‐ limonene Using

the T

‐ REX Model (ppm).

USE Rate

(lb a.i./A) DIETARY

‐ BASED

EECs KENAGA VALUES

(Upper Bound)

Orange Guard

‐ Ornamental

6 apps. ; 7‐day retreatment

interval 4.6 Short Grass 4,816

Tall Grass 2,207

Broadleaf plants 2,709

Fruits/pods/seeds 301

Arthropods 1,886

18.4 Short Grass 19,265

Tall Grass 8,830

Broadleaf plants 10,836

Fruits/pods/seeds 1,204

Arthropods 7,545

55.2 Short Grass 57,795

Tall Grass 26,489

Broadleaf plants 32,509

Fruits/pods/seeds 3,612

Arthropods 22,636

Avenger Burndown

Herbicide Agricultural

Crops

12 apps.; 2

‐ day retreatment

interval 34.6 Short Grass 80,893

Tall Grass 37,076

Broadleaf plants 45,502

Fruits/pods/seeds 5,056

Arthropods 31,683

Table 11. Avian Dose

‐ based EECs (mg/kg

‐ bw)/Avian Classes and Body Weights (grams) for Orange

Guard

‐ Ornamental plants in Greenhouses, nurseries, Christmas tree plantations, and landscapes

(6 applications per year, 7

‐ day retreatment interval)

Food Item Rate= 4.6 (lb a.i./A) Rate=18. 4 (lb a.i./A) Rate= 55.2 (lb a.i./A)

Small Med. Large Small Med. Large Small Med. Large

Short Grass 5,485 3,128 1,400 21,941 12,512 5,602 65,822 37,535 16,805

Tall Grass 2,514 1,434 642 10,056 5,734 2,567 30,169 17,203 7,702

Broadleaf plants 3,085 1,759 788 12,342 7,038 3,151 37,025 21,113 9,453

Fruits/pods 343 195 88 1,371 782 350 4,114 2,346 1,050

Arthropods 2,148 1,225 548 8,593 4,900 2,194 25,780 14,701 6,582

Seeds 76 43 19 305 174 78 914 521 23324

Table 12. Avian Dose

‐ based EECs (mg/kg

‐ bw)/Avian Classes and Body Weights (grams)

‐ Avenger

Burndown Herbicide

– Agricultural Crops (12 applications per year, 2

‐ day retreatment interval)

Food Item Rate

‐ 34.6 lb a.i./A

small med. large

Short Grass 92,129 52,536 23,521

Tall Grass 42,226 24,079 10,780

Broadleaf plants 51,823 29,551 13,231

Fruits/pods 5,758 3,283 1,470

Arthropods 36,084 20,577 9,212

Seeds 1,280 730 327

Table 13. Mammalian Dose

‐ based EECs (mg/kg

‐ bw)/Mammal Size Classes and Body Weights

(grams) for Orange Guard

‐ Ornamental plants in greenhouses, nurseries, Christmas tree

plantations, and landscapes (6 applications per year, 7

‐ day retreatment interval)

Food Item Rate= 4.6 (lb a.i./A) Rate= 18.4 (lb a.i./A) Rate= 55.2 (lb a.i./A)

Small Med. Large Small Med. Large Small Med. Large

Short Grass 4,592 3,174 736 18,368 12,694 2,943 55,103 38,083 8,830

Tall Grass 2,105 1,455 337 8,418 5,818 1,349 25,255 17,455 4,047

Broadleaf plants 2,583 1,785 414 10,332 7,141 1,656 30,995 21,422 4,967

Fruits/pods 287 198 46 1,148 793 184 3,444 2,380 552

Arthropods 1,798 1,243 288 7,194 4,972 1,153 21,582 14,916 3,458

Seeds 64 44 10 255 176 41 765 529 123

Table 14. Mammalian Dose

‐ based EECs (mg/kg

‐ bw)/Mammal Size Classes and Body Weights

(grams) for Avenger Burndown Herbicide

– Agricultural Crops (12 applications per year, 2

‐ day

retreatment interval)

Food Item Rate

‐ 34.6 lb a.i./A

small med. large

Short Grass 77,125 53,304 12,359

Tall Grass 35,349 24,431 5,664

Broadleaf plants 43,383 29,983 6,952

Fruits/pods 4,820 3,331 772

Arthropods 30,207 20,877 4,840

Seeds 1,071 740 172

Plants

Exposure to terrestrial plants is estimated using the TerrPlant (v1.2.2) screening model. TerrPlant

estimates potential exposure from a single application using default assumptions for runoff (2%

given solubility is between 10 and 100 ppm) and spray drift (1% given a ground application of a25

liquid formulation) ( Table 15 ). Because there were no effects in the seedling emergence study,

this assessment only considers the exposure via spray drift (runoff is not included). See

APPENDIX 6 for more information.

Table 15. EECs on Plants Following Label

‐ Specified Ground Applications of d‐ limonene Using the

TerrPlant Model (lb a.i./A)

USE RATE

(lb a.i./A) EECs from

Spray Drift

Orange Guard

‐ Ornamental 18.4 0.184

55.2 0.551

Avenger Burndown

‐ Ag. Crops 34.6 0.346

VI. Risk Characterization

A. Risk Estimation

‐ Integration of Exposure and Effects Data

Toxicity data and exposure estimates are used to evaluate the potential for adverse ecological

effects on non

‐ target species. For this screening

‐ level assessment of d‐ limonene the

deterministic risk quotient method is used to provide a metric of potential risks. The RQ is a

comparison of exposure estimates to toxicity endpoints; estimated exposure concentrations are

divided by acute and chronic toxicity values. The resulting unitless RQs are compared to the

Agency’s levels of concern (LOCs) (see Table 16 ), which are the Agency’s interpretive policy such

that when LOCs are exceeded, the need for regulatory action may be considered. These criteria

are used to indicate when the use of a pesticide, as directed on the label, has the potential to

cause adverse effects on non

‐ target organisms.

Table 16. Agency Levels of Concern (LOC).

Risk Description RQ Taxa

Acute Potential for acute risk to non

‐ target organisms

which may warrant regulatory action in

addition to restricted use classification acute RQ > 0.5 aquatic animals,

mammals, birds

Acute Listed

Species Listed species may be potentially affected by

use acute RQ > 0.05 aquatic animals

acute RQ > 0.1 mammals and

birds

Chronic Potential for chronic risk may warrant

regulatory action, listed species may potentially

be affected through chronic exposure chronic RQ > 1 all animals

Non

‐ Listed and

Listed Plant Potential for effects in non

‐ listed and listed

plants RQ > 1 all plants26

1. Non

‐ target Aquatic Animals and Plants

On an acute exposure basis, d‐ limonene is classified as “slightly toxic” to freshwater fish and

invertebrates. With a peak EEC of 323.6 ug a.i./L, the resulting RQ values were below the LOC

thresholds (acute and ES) at 0.004 and 0.0083 for fish and invertebrates, respectively ( Table 17 ).

However, this is based on a limited toxicity set with only one species of freshwater fish tested

and no data for estuarine/marine (E/M) species (fish or invertebrates). In the absence of data,

the freshwater species will serve as a surrogate for E/M species, however, there is uncertainty

with using freshwater values as a proxy for E/M species, especially given tha t only one species of

freshwater fish was tested.

Toxicity data are not available to assess the risk to fish and invertebrates on a chronic exposure

basis. Based on the highest 60

‐ day EEC (210.9 ug/L), and the acute toxicity value for fish (80,000

ug/L), d‐ limonene would need to be 379 times more toxic on a chronic exposure basis to reach

the level of concern. Likewise, for invertebrates, based on the highest 21

‐ day EEC (272 ug/L) and

the acute toxicity value (39,000 ug/L), d‐ limonene would need to be 143 times more toxi c on a

chronic exposure basis to reach the level of concern. In an attempt to gain further information

on the chronic risk, a structure activity analysis (QSAR) was run but it did not provide useful

information because of the poor fit with the available acute data. When chronic data are lacking,

an acute to chronic ratio (ACR) may be used to inform for the taxa, but with no chronic data for

d

‐ limonene, this type of analysis is not possible for the active ingredient. As an alternative,

Raimondo et. al, (2007) 32 provides an ACR value based on a dataset of 456 same species pairs of

acute and chronic data. Using the 90 th percentile ACR values of 90.0 and 68.3 for fish and

invertebrates, respectively, there would not be any exceedances at the highest application rate.

There is, however, a high degree of variability in the estimated ACRs with ranges of (1.2

‐ 2,121)

for fish and (1.1

‐ 18,550) for invertebrates. While the majority of chemicals will likely have ACRs

at or below the 90 th percentile mentioned above, there is the uncertainty of over or

underestimating the chronic risk given the high variability in the dataset. Based on the 90 th

percentile ACR, risk is not anticipated at this time.

There are no LOC exceedances for vascular and non

‐ vascular aquatic plants.

Table 17. Aquatic Exposure RQ Values for d‐ Limonene

Taxonomic

Group Exposure

Type Toxicity (ug/L) EEC

( μg/L ) RQ Exceeds

LOC

(Y/N)

Freshwater Fish Acute LC 50 = 80,000 323.6 0.004 N

Freshwater

Invertebrate Acute LC 50 = 39,000 323.6 0.008 N

Non

‐ listed EC 50 = 9,353 323.6 0.035 N

32 Raimondo, S, Montague, B. , and Barron, M. (2007) De terminants of Variability in Acute to Chronic Ratios for

Aquatic Invertebrates and Fish. Environ Toxicol Chem (26) No. 9 pp 2019-2023.27

Taxonomic

Group Exposure

Type Toxicity (ug/L) EEC

( μg/L ) RQ Exceeds

LOC

(Y/N)

Aquatic

Vascular plants Listed NOAEC =1,731 323.6 0.187 N

Aquatic Non

‐

Vascular Non

‐ listed EC 50 =29,650 323.6 0.011 N

Listed NOAEC = 3,125 323.6 0.104 N

Non

‐ Target Terrestrial Animals

Mammals

For the Orange Guard uses at the higher application rates (i.e., 18.4 and 55.2 lb a.i./A), there

were acute and endangered species (ES) LOC exceedances for the majority of size/dietary class

combinations ( Table 18 ). The shaded cells indicate the acute LOC (0.5) exceedances and the bold

indicate the additional ES LOC (0.1) exceedances. The acute exceedances (i.e., LOC ≥ 0.5) range

from 0.64

‐ 1.9 for the 18. 4 lb a.i. rate and from 1.02

‐ 5.7 for the 55.2 pounds a.i./A rate.

In terms of chronic exposure, there were LOC exceedances (i.e., LOC ≥ 1.0) for the majority of

size/dietary class co mbinations and the exceedances ranged from 0.96

‐ 33 and 1.19

‐ 100 for the

18.4 and 55.2 lb a.i./A rates, respectively.

For the lower rate (4.6 lb a.i./A), the acute RQ was exceeded for the small mammal eating short

grass exclusively (RQ=0.47) and the ES LOC was exceeded for all size classes eating short grass,

tall grass, and broadleaf plants and the small and medium mammals consuming arthropods

( Table 18 ).

On a chronic exposure basis, there were exceedances that ranged from 1.5

‐ 8.4 for the 4.6

pounds a.i./A rate.

For the Avenger Burndown uses at the 34.6 lb a.i./A, applied every 2 days for a total of 12

applications, the RQs are higher than the scenarios for the Orange Guard. The acute RQs

exceedances ranged from 0.5

‐ 7.98 and the chronic exceedances ranged from 1.67

‐ 140 (Table

19).28

Table 18. Mammalian Dose Based RQs

‐ Orange Guard Ornamental plants in Greenhouses,

nurseries, Christmas Tree plantations, and landscapes (6 applications per year, 7

‐ day retreatment

interval)

Food Item Rate 4.6 lb a.i./ A

Small=15 g Medium=35g Large

‐ 1000g

Acute Chronic Acute Chronic Acute Chronic

Short Grass 0.47 8.36 0.41 7.14 0.22 3.83

Tall Grass 0.22 3.83 0.19 3.27 0.10 1.75

Broadleaf plants 0.27 4.70 0.23 4.02 0.12 2.15

Fruits/pods 0.03 0.52 0.03 0.45 0.01 0.24

Arthropods 0.19 3.27 0.16 2.80 0.09 1.50

Seeds 0.01 0.12 0.01 0.10 0.00 0.05

Rate 18.4 lb a.i./ A

Short Grass 1.90 33.43 1.62 28.55 0.87 15.31

Tall Grass 0.87 15.32 0.74 13.09 0.40 7.02

Broadleaf plants 1.07 18.80 0.91 16.06 0.49 8.61

Fruits/pods 0.12 2.09 0.10 1.78 0.05 0.96

Arthropods 0.74 13.09 0.64 11.18 0.34 5.99

Seeds 0.03 0.46 0.02 0.40 0.01 0.21

Rate 55.2 lb a.i./ A

Short Grass 5.70 100.29 4.87 85.66 2.61 45.92

Tall Grass 2.61 45.96 2.23 39.26 1.20 21.05

Broadleaf plants 3.21 56.41 2.74 48.19 1.47 25.83

Fruits/pods 0.36 6.27 0.30 5.35 0.16 2.87

Arthropods 2.23 39.28 1.91 33.55 1.02 17.98

Seeds 0.08 1.39 0.07 1.19 0.04 0.64

Table 19. Mammalian Dose Based RQs

‐ Avenger Burndown Herbicide

– Agricultural Crops (12

applications per year, 2

‐ day retreatment interval)

Dose

‐ based RQs

(Dose

‐ based

EEC/LD50 or

NOAEL) Rate 34.6 lb a.i./ A

Small=15 g Medium=35g Large

‐ 1000g

Acute Chronic Acute Chronic Acute Chronic

Short Grass 7.98 140.37 6.81 119.90 3.65 64.27

Tall Grass 3.66 64.33 3.12 54.95 1.67 29.46

Broadleaf plants 4.49 78.96 3.83 67.44 2.05 36.15

Fruits/pods 0.50 8.77 0.43 7.49 0.23 4.02

Arthropods 3.12 54.98 2.67 46.96 1.43 25.17

Seeds 0.11 1.95 0.09 1.67 0.05 0.8929

Birds

The toxicity data set for birds is limited as there are no acute oral or reproductive studies

(chronic exposure). Based on the available dietary exposure study, d‐ limonene is classified as

“practically non

‐ toxic” with an LC 50 value of >5,600 mg a.i./kg diet. Since the endpoint from this

study is non

‐ definitive ( i.e., it is a ‘greater than’ value), it will not be used to calculate RQs.

Terrestrial Invertebrates

Data are not available to assess the risk to invertebrates.

Non

‐ target Terrestrial Plants

The risk to plants was assessed using TerrPlant ( Appendix 6 ) and then refi ned with an analysis

using AgDrift ( Appendix 7 ). From the TerrPlant analysis, there were no RQ exceedances for

applications at the 4.6 or 18.4 lb a.i./A rate. At the 34.6 and 55.1 lb a.i./A rates, there were LOC

exceedances (RQs= 1.8 and 2.9, respectively) for listed mono cots ( Table 20 ).

T able 20. Screening Level Analysis

‐ Terr Plant RQs

Plant Type Rate lb a.i./A

18.4 34.6 55.1

Monocot <0.1 0.12 0.20

Monocot (listed) 0.97 1.82 2.91

Dicot <0.1 <0.1 <0.1

Dicot (listed) 0.14 0.26 0.42

Using the Ag Drift analysis, at the 4.6 lb a.i./A rate, the distance to no longer exceed the LOC

was 0

‐ 3 feet for non

‐ listed species and 3

‐ 23 feet for listed species. For the higher rates (18.4

‐

55.1 lb a.i./A, the distance ranged from 3

‐ 19 feet for non

‐ listed species and 9

‐ 305 feet for listed

species (Table 21 ).

Table 21. Ag Drift Analysis

‐ Distance from th e Field to no longer exceed the LOC

Product Rate Plant Type Listed Non

‐ listed

Avenger

Med

‐ Coarse Droplet 34.6 Monocot 75.46 6.56

Dicot 9.84 3.23

Orange Guard

(Fine Droplet) 4.6 Monocot 22.97 3.28

Dicot 3.28 0

18.4 Monocot 91.86 6.56

Dicot 13.2 3.28

55.2 Monocot 305.11 19.68

Dicot 39.37 9.8430

B. Risk Description

Risks to Aquatic Organisms

Animals

On an acute exposure basis, the risk to freshwater fish and invertebrates is considered low. Data

are not available for estuarine/marine (E/M) species (fish or invertebrates). In the absence of

data, the freshwater species may serve as a surrogate for E/M species, thus, the acute risk is

anticipated to be low. However, there is uncertainty given th e paucity of data for d

‐ limonene.

Toxicity data are not available to assess the risk to fish and invertebrates on a chronic exposure

basis. Using the 90 th percentile ACR (see earlier discussion of Raimondo et. al., in Risk

Characterization) to estimate the chronic toxicity values, risk is not anticipated for fish or

invertebrates at this time. However, given the high variability in the ACR analysis, having chronic

data for d

‐ limonene would greatly reduce the uncertainty in this assessment.

Plants

All of the RQ s for aquatic vascular and non

‐ vascular plants are below the LOCs for risk to listed

and nonlisted species. Therefore, likelihood of direct risk to aquatic plants from the use of d‐

limonene is considered low.

Risks to Terrestrial Organisms

Mammals

d‐ limonene is classified as “practically non

‐ toxic” to mammals on an acute oral basis, however,

because of the high application rates and frequency of applications, the expected residues on

the dietary items are high at the 18.4, 34.6 and 55.1 lb a.i./A application rates/use scenarios,

thus leading to exceedances for the majority of size/dietary class co mbinations. At the 4.6 lb

a.i./A rate, the only exceedance for was the small mammal feeding exclusively on short grass.

There is uncertainty with the exposure to terrestrial organisms for several reasons. Based on the

chemical properties/environmental fate data, d‐ limonene is expected to volatilize rapidly (with a

vapor pressure of <3 mm of Hg). At this time there is only one study (MRID 47548301) that

characterizes the foliar dissipation half

‐ life and a minimum of 3 studies are needed to move

away from the 35

‐ day default assumption in the TREX model. To further explore the risk to

terrestrial animals from exposure to d‐ limonene, the available magnitude of residues study was

reviewed and is considered here. The magnitude of residue study for mustard greens (MRID

47548301) tes ted two products (QRD 400/QRD 416 which contained a mixture of 3 active

ingredient terpenes, α‐ terpinene, ρ‐ cymene, and d‐ limonene) that were applied to mustard

green foliage at a rate of 2.6 and 2.4 lb a.i./A for QRD 400 and QRD 416, respectively. Leaves

were harvested at 0

‐ , 1

‐ , and 4

‐ hours. d‐ limonene levels generally dropped below the Limit of

Quantification (LOQ=0.05 ppm) at 1

‐ hour. The rate of decline for d‐ limonene ranged from 2.8 to

4.67

‐ hr

. Adjusting the 2.4 or 2.6 lb a.i./A to the maximum rate for d

‐ limonene (34.6 lb a.i./A), the

time required for the d‐ limonene concentrations to drop below the LOQ ranged between 3 and31

15 hours. This shorter half

‐ life also seems in

‐ line with the registrant suggested reapplication

intervals as short as every 2 days. To explore the expected residues on food items, the T

‐ REX

model was run using a foliar dissipation half

‐ life of 2 days. When the high end exposure scenario

(34 lb a.i./A, 12X, 2

‐ day interval) was modeled, the acute RQ exceedances ranged from 0.5

‐ 1.6

and the chronic RQs ranged from 1.5

‐ 28 for a variety of size/dietary classes. The lower exposure

scenario (4.6 lb a.i./A, 6X, 7

‐ day interval), did not have any acute LOC exceedances (the ES LOC of

0.1 was exceeded to smal l mammals feeding on short grass; RQ = 0.12) and for chronic exposure,

there were exceedances for small and medium mammals feeding on short grass and broadleaf

plants with RQs around 1.01

‐ 2.10.

Based on the available data, there are risks (acute and chronic) identified for mammals at the

higher foliar exposure scenarios (18.4, 34.6 and 55.1 lb a.i./A rates). At the lower rate of 4.6 lb

a.i./A (using the 2

‐ day half

‐ life), risk to mammals (acute) is not anticipated. While there is an

endangered species LOC exceedance (RQ=0.12) it is only for the 15 gram mammal feeding

exclusively on short grass. To refine further, the LD 50 was reported separately for males and

females and the lowest value [4400 mg a.i./kg

‐ bw (M)] was used for the endpoint in this risk

assessment but if the higher value [5100 mg a.i./kg

‐ bw (F)] was used then there would be no

exceedances, thus, the risk is between an RQ of 0.10 and 0.12 for the 4.6 lb a,i./A rate

.

On a chronic exposure basis, there were exceedances for small and medium mammals feeding

on short grass and broadleaf plants with RQs around 1.01

‐ 2.10. The TREX model indicates that

these exceedances would occur in 17 out of the 56 days (the application pattern is 6 applications

every 7 days), thus, the exceedances are likely occurring the day of application and lasting 1

‐ 2

days. For additional characterization, because the effect was a small reduction in maternal

weight gain, the LOAEC value (500 mg a.i./kg

‐ bw) was used to gauge if exceedances would occur

at the actual dose that ca used the effect. When modeling the endpoint of 500 mg a.i./kg

‐ bw, the

only chronic exceedance was an RQ of 1.05 for the 15 gram mammal feeding exclusively on short

grass. Altogether, the risk to mammals is not considered high at the lowest application scenario.

Additional data for the foliar dissipation half

‐ life would reduce the uncertainty in this analysis.

Bird s

Because there was no mortality or sublethal effects at the highest treatment level tested for

birds (dietary study only), the RQs for acute or chronic effects to birds were not calculated in the

Risk Estimation section of this assessment. Therefore, in order to gain a better understanding of

how the EEC s for the application rates for d‐ limonene relate to the toxicity data currently

available, a ratio of the EEC/acute endpoint was calculated under the assumption that the

highest level tested is the endpoint value. While this analysis is of limited utility for the high rates

(18.4, 34.6, 55.1 lb a.i./A) because the highest treatment level the animal was exposed to was

lower than the EECs by a large margin for the majority of feed items, it can provide useful

information for the lower rate. At 4.6 lb a.i./A., the EEC of 4816 ppm is lowe r than the highest

test concentration (5600 ppm) at which no mortality or sublethal effects were observed, thus,

the risk to birds on an acute exposure basis is considered to be low.32

As discussed in the mammal section above, there is uncertainty with regard to the foliar

dissipation half

‐ life. In order to explore the shorter half

‐ life of 2

‐ days, the EECs from TREX with a

2

‐ day foliar dissipation half

‐ life were compared to the 5600 ppm endpoint. The risk to birds at

the lowest rate was low. In contrast to using the default half

‐ life, when using the shorter half

‐ life,

the 18.4 lb a.i./A rate could also be analyzed because the EECs were below the highest test

concentration in the toxicity test. For the 18.4 lb a.i./A application scenario, the EEC of 4844 ppm

is lower than the highest test concentration at which no mortality or sublethal effects were

observed (5600 ppm), thus, the risk to birds on an acute exposure basis is considered to be low.

Based on the available data, risk is presumed for the highest application scenarios (the 34.6 and

55.1 lb a.i./A rates). While there is uncertainty because the only data available is from a dietary

study (which may underestimate the risk compared to an acute oral study), and a sufficient

number of foliar dissipation values are not available at this time, the risk to birds from the lower

rates of 4.6 and 18.4 lb a.i./A is considered to be low. An acute oral study (tested up to

environmentally relevant EECs or within the physiological limi ts of the bird) and additional data

for the foliar dissipation half

‐ life would reduce the uncertainty in this analysis. Additionally, the

risk for birds on a chronic exposure basis is uncertain without data.

Terrestrial invertebrates

Due to a lac k of toxicity data, at this time the risk to terrestrial invertebrates is presumed given

that d

‐ limonine is registered as an insecticide.

Terrestrial Plants

Two different analyses were used to assess the risk to terrestrial plants. In the screening level

analysis with TerrPlant, there were no RQ exceedances for applications at the 4.6 or 18.4 lb a.i./A

rate. At the 34.6 and 55.1 lb a.i./A rates, there were LOC exceedances (RQs= 1.8 and 2.9,

respectively) for listed monocots.

Using the Ag Drift analysis, different factors related to the droplet size were incorporated based

on language for reducing spray drift on the Avenger label. For this assessment, the Avenger use

(34.6 lb a.i./A) was assigned to a medium

‐ coarse droplet and the other assessed rates (Orange

Guard label) were assigned to the default

‐ fine droplet size. At the 4.6 lb a.i./A rate, the distance

to no longer exceed the LOC was 0

‐ 3 feet for non

‐ listed species and 3

‐ 23 feet for listed species.

For the higher rates (18.4

‐ 55.1 lb a.i./A), the distance ranged from 3

‐ 19 feet for non

‐ listed

species and 9

‐ 305 feet for listed species.

Based on these analyses, there is a risk identified from spray drift to non

‐ target listed and non

‐

listed plants with the exception of non

‐ listed dicots at the 4.6 lb a.i./A rate. There was one

“minor” plant damage incident reported as well (See Review of Incident data).33

Review of Incident Data

Reviews of the Ecological Incident Information System (EIIS) and the Avian Incident Monitoring

System (AIMS) 33 were conducted on 9/18/14. There are no reported incidents for d‐ limonene in

the EIIS or AIMS databases. In addition to the incidents recorded in EIIS and AIMS, additional

pesticide incidents are reported to the Agency in aggregated incident reports. Ecological

incidents reported in aggregate reports include those categorized as ‘minor fish and wildlife’ (W

‐ B), ‘minor plant’ (P

‐ B), and ‘other non

‐ target’ (ONT) incidents. ‘Other non

‐ target’ incidents

include reports of adverse effects to insects and other terrestrial invertebrates. A query of the

aggregate incident report on 9/25/14, found a single incident reported for HOME DEFENSE

INDOOR INSECT KILLER

‐ RTU (EPA product number: 045987

‐ 000239). The incident was reported

as ‘minor plant’ damage during the time period of 4/1/04

‐ 6/30/04. No further information is

available.

Federally Threatened and Endangered (Listed) Species Concerns

Before completing this Registration Review, the Agency will conduct an ecological risk

assessment to address the Agency’s obligations under both the Endangered Species Act (ESA)

and FIFRA. While the risk assessment supporting this proposed interim Registration Review

decision evaluates risks to species that are not subject to the ESA, EPA is still in the process of

conducting a risk assessment for endangered and threatened (listed) species and their

designated critical habitats for d‐ limonene. In this proposed interim decision, therefore, EPA has

not completed effects determinations for listed species associated with the registered uses of d‐

limonene.

At this time, EPA has not fully developed its risk assessment process for listed species. In

November 2013, the EPA, along with the U.S. Fish & Wildlife Service (USFWS), the National

Marine Fisheries Service (NMFS) (collectively, the Services), and the U.S. Department of

Agriculture (USDA ) released a summary of their joint Interim Approaches for assessing risks to

listed species from pesticides. The Interim Approaches were developed jointly by the Agencies in

response to the National Academy of Sciences’ (NAS) recommendations and reflect a common

approach to risk assessment shared by the Agenci es as a way of addressing scientific differences

between the EPA and the Services. The NAS report, available at

http://www.nap.edu/catalog.php?record_id=18344

, outlines recommendations on specific

scientific and technical issues related to the development of pesticide risk assessments that EPA

and the Services must conduct in connection with their obligations under the ESA and FIFRA. The

joint Interim Approaches were released prior to a stakeholder workshop held on November 15,

2013. In addition, the EPA presented the joint Interim Approaches at the December 2013

Pesticide Program Dialogue Committee (PPDC) and State

‐ FIFRA Issues Research and Evaluation

Group (SFIREG) meetings, allowing additional opportunities for stakeholders to comment on the

Interim Approaches. As part of a phased, iterative process for developing the Interim

Approaches, the Agencies will also consider public comments on the Interi m Approaches in

connection with the development of upcoming Registration Review decisions. The details of the

33 http://www.abcbirds.org/abcprograms/ policy/pesticides/aims/aims/index.cfm34

joint Interim Approaches are contained in the white paper “Interim Approaches for National

‐

Level Pesticide Endangered Species Act Assessments Based on the Recommendations of the

National Academy of Sciences April 2013 Report,” dated November 1, 2013, available at

http://www.epa.gov/espp/2013/nas.html

.

Clean Water Act

Limonene is not identified as a cause of impairment for any water bodies listed as impaired

under section 303(d) of the Clean Water Act, based on information provided at

http://iaspub.epa.gov/tmdl_waters10/attains_na tion_cy.cause_detail_303d?p_cause_group_id=885

. In addition, no Total Maximum Daily Loads (TMDL) have been developed for limonene, based on

information provided at

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmd l_pollutant_detail?p_pollutant_group_id=885&p_pollutan

t_group_name=PESTICIDES

. More information on impaired water bodies and TMDLs can be found at

http://www.epa.gov/owow/tmdl/

.

Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental,

reproductive, and general or systemic toxicity. These studies include endpoints which may be

susceptible to endocrine influence, including effects on endocrine target organ histopathology,

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss,

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and

chronic studies that assess growth, developmental and reproductive effects in different

taxonomic groups. As part of its reregistration decision for d

‐ limonene, EPA reviewed these data

and selected the most sensitive endpoints for relevant risk assessment scenarios from the

existing hazard database. However, as required by FFDCA section 408(p), d

‐ limonene is subject

to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP).

EPA has developed the EDSP to determ ine whether certain substances (including pesticide active

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by

a “naturally occurring estrogen, or other such endocrine effects as the Administrator may

designate.” The EDSP employs a two

‐ tiered approach to making the statutorily required

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal

systems. Chemicals that go through Tier 1 screening and are found to have the potential to

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA

will determine which, if any, of the Tier 2 tests are necessary based on the available da ta. Tier 2

testing is designed to identify any adverse endocrine

‐ related effects caused by the substance,

and establish a dose

‐ response relationship between the dose and the E, A, or T effect.35

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October

2009 and February 2010, EPA issued test orders/data call

‐ ins for the first group of 67 chemicals,

which contains 58 pesticide active ingredients and 9 inert ingredients. A second list of chemicals

identified for EDSP screening was published on June 14, 2013 34 and includes some pesticides

scheduled for registration review and chemicals found in water

. Neither of these lists should be

construed as a list of known or likely endocrine disruptors.

For further information on the status of the EDSP, the policies and procedures, the lists of

chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our

website. 35

34 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of

chemicals.

35 http://www.epa.gov/endo/36Appendix1.SummaryofLabeledUsesford‐LimoneneCropsorUseSite%AIFormulation/EquipmentMaxAppRate(lba.i./A;unlessnoted)Maximum#ofAppl.perSeason/Inter‐val(days)Maximumlba.i./A/Season(year)CommentsCommercial/Inst./Household/dwelling;Spottreatment,crack&crevice,surfacespray,directspray10AerosolcanNSAsneededNSSprayfor10sec.Commercial/Inst./HouseholdCrack&creviceOutdoorgeneralspraySurfacetreatment4.0Aerosolcan0.031lba.i./200ft2NSNS15ozcontainer/200ft20.031lba.i./200ft2RTU‐PetShampoo5Liquid0.429lba.i./gal0.04lba.i./12ozNS/7NSSpongeon,dip,sprinkle78ECNSNSNS1.5oz/1gal(product)0.663lba.i./beadResidential/turfOutdoorgeneralsurfacespray,lawnsCrack&crevicespray1Aerosol/RTU‐SprayNSDonotapplymorethan1timeperday/NSAerosolcan,0.0826lba.i./galRTU‐0.009lba.i./14flozHousehold/dwellingsCrack&crevicetreatment;indoorandoutdoorgeneralsurfacespray;perimetertreatment5.8RTU‐SprayerNSSaturateareaNSNS8.139lb/gal0.47lba.i./galHousehold/Commercial/InstitutionalFireantmoundcrack&crevicespray;directedspray,mounddrench;perimetertreatment5.8Sprayer0.2265lba.i./moundNSNS1to3(4)Sprayer;0.5gal/moundSprayvolumeperAreanotspecified.Assuming40moundsperA=9.06lba.i./A37CropsorUseSite%AIFormulation/EquipmentMaxAppRate(lba.i./A;unlessnoted)Maximum#ofAppl.perSeason/Inter‐val(days)Maximumlba.i./A/Season(year)CommentsOrnamentalplantsingreenhouses,nurseries,Christmastreeplantations,andlandscapes(residentialcommercial,industrial)5.8PumpsprayerHandheldsprayerGround4.66/727.6Rateswereexpressedasdilutionof(1:4;0.092lba.i./galwater),or(1:6)withvariousfinishsprayvolumes.“rowcrops25‐50gal/A;vinecrops50‐200gal/A,treecrops100‐400gal/A,greenhouse100gal/10,000sqft,600galperA‐forestry”.18.46/7110.436.86/7220.840.16/7240.655.26/7331.2Voidtreatment;woodsurfacetreatment;95RTUInjectioneq.5.19lba.i./100ft2AsneededNS1oz/ft20.052lba.i./ft2Soildrench/Soiltreatment(fireant)78.2Pumpspraybottle0.3534lb/2gal;0.0883lb/0.5galNSNSHousehold/outdoorpremisesCrack&crevice10RTUAerosolcanNSNSNSAerosolcan;Sprayfor10secondsCommercial/premisesCracks&crevice;generalsurface4.0RTUSprayer0.030lba.i./200ft2AsneededNS0.246lba.i./gal‐27gal/ATreatedstrip;clothingtreatment;skincontact4.0Wristband/Impreg.materialNSAsneededNSBordersarounddriveways,patios,sidewalks,maturetreesandornamentals,buildings,residentialgreenhouses,fencerows,flowerbedsConc.(70%)/RTU(17.5%)Sprayer1.28‐1.47lba.i./gal(dilution)51‐59lba.i./A*12Weedpost‐emergenceNS*Assumed40gallonsperAbecausethelabeldidnothaveafinishsprayvolumetocompletetherate.Needfurtherclarificationonlabeltoreduceuncertainty.Giventheuncertaintyandtheuseasperimeter/spottreatment,thisassessmentwillusethehighscenariosabovetoinformontheriskforthisuse.38CropsorUseSite%AIFormulation/EquipmentMaxAppRate(lba.i./A;unlessnoted)Maximum#ofAppl.perSeason/Inter‐val(days)Maximumlba.i./A/Season(year)CommentsAg.Crops:Brassicaveg;citrus;grapes;herbs;leafyveg;legumeveg;pomefruit;root&tuberWeedpost‐emergence/burndown55%GroundSprayer‐Directed/HoodedsprayerBroadcastandSpottreatment34.612(2)NSLabelstatesdonotexceed8.5gallonsofproductperacreperapplication(4.07lba.i./gal*8.5gal/A=34.60lba.i./A).Household/domesticdwellingsoutdoorpremises;residentiallawns.23RTUGardenhose‐endsprayer0.454lba.i/1000ft2(19.79)12NSForcontrolofalgaeandmoss.39

Appendix 2. Estimation Aerobic Metabolism

Misra and Pavlostathis 36 (1997) conducted batch experiments to evaluate biodegradation rates of

several monoterpenes, including limonene, in liquid and soil

‐ slurry systems, under aerobic conditions.

Biodegradations was demonstrated through the depletion of the monoterpene mass, CO 2 production,

and a corresponding increase in biomass. In liquid cultures with no soil, monoterpene degradation

followed a Monod or Michaelis

‐ Menten type kinetics equation (Rafai and Newell, 1998) 37 (eq. 1),

μ ൌ

‐ μ max ∗ ௌ

௄௦ାௌ (eq. 1)

where μ is the specific growth rate, s (mg/L) is the concentration in solution, t is time (days), μ max is the

maximum reaction rate (mg/L per day), and K

s (mg/L) is the substrate saturation constant (i.e.,

saturation constant at half μ max ). In the Monod model, the growth rate is related to the concentration of

a growth limiting substrate through the parameters μ max and K

s (Rifai and Newell, 1998; Okpokwasili and

Nweke 38

, 2005). Additionally, Monod related the yield coefficient (Y x/s ) eq. 2 to the specific rate of

biomass growth (μ) and the specific rate of substrate utilization (q) (eq. 3).

Y x/s = ௗ௫

ௗ௦ (eq. 2)

μ = Y x/s / ܺ

. ௗ௦

ௗ௧ ≈ Y x/s*q (eq. 3)

Further, Rifai and Newell (1998) provided a method to estimate a first

‐ order decay rate to estimate a

half

‐ life for input into the fate models. They suggest that high values of K

s (i.e., K

s >>S) the Monod

equation simplifies to eq. 4.

ௗௌ

ௗ௧ = ‐ u max ௌ

௄௦ (eq. 4)

And that the first

‐ order decay constant, k, (day

‐ 1 ) is estimated from the expression μ max /K

s .

Misra and Pavlostathis (1997) reported in values (Table 2) for

‐ μ max 0.022 and 0.024 (h

‐ 1 ) and K

s 17 and

32 (mg l

‐ 1 ) for solutions below and above solubility, respectively. These values result in half

‐ life

estimates of 22.7 and 38.5 days for below and above solubility, respectively.

36 Misra and Pavlostathis. 1997. Appl. Microbiol. Biotechnol. 47:572

‐ 577.

37 Rifai and Newell, 1998. https://info.ngwa.org/GWOL/pdf/982664575.PDF

38 Okpokwasili, G.C. and C.O. Nweke, 2005. Microbial growth and substrate utilization kinetics. African J. Biotech. 5:305

‐ 317.40

Appendix 3. SWCC EEC

Table 1. SWCC d‐ limonene estimated Peak, 96

‐ hour, 21

‐ day and 60

‐ day average concentrations in standard

farm pond for max rates.

Pond Peak 4

‐ day 21

‐ day 60

‐ day

Scenario 1

‐ year in 10

‐ year concentration (μg/L)

NC Sweet Potato 2390 1640 762 353

FL strawberry 2370 1490 486 198

GA Pecans 2330 1670 663 318

CA lettuce 2010 1540 687 279

FL tomato 1850 1110 525 242

GA Onion W irrig 1680 1130 479 223

FL citrus 1640 864 359 194

PA tomato 1310 935 481 224

TN nursery 1270 1020 556 332

NJ nursery 1260 1140 1050 847

PA apple 1120 792 448 194

CA almond W irrig 1090 695 314 173

PA apple 991 657 403 226

MI beans 986 605 266 139

ME potato 910 696 359 168

MI nursery 872 833 756 633

ND canola 809 470 222 114

OR Xmas Tree 709 456 277 189

FL nursery 697 448 219 177

OR nursery 663 466 303 191

CA nursery 581 390 224 150

CA onion W irrig 558 412 192 102

CA grapes W irrig 541 461 232 113

OR filberts 508 377 254 168

CA citrus W irrig 413 290 158 101

OR filberts 408 318 196 109

OR mint 398 307 226 149

IDN potato W irrig 363 271 198 140

PA turf 345 242 190 131

OR apple 339 258 215 153

ID potato W irrig 275 208 116 83.9

OR apple 221 163 137 71.341

Appendix 4. Representative Model Outputs

**Surface Water Calculator (SWCC)**

**Summary of Water Modeling of d-limonene and the USEPA Standard Pond**

Estimated Environmental Concentrations for d-limonene are presented in Table

1 for the USEPA standard pond with the NCSweetPotatoSTD field scenario. A

graphical presentation of the year-to-year peaks is presented in Figure 1.

These values were generated with the Surface Water Concentration Calculator

(SWCC Version 1.106). Critical input values for the model are summarized in

Tables 2 and 3.

This model estimates that about 1.2% of d-limonene applied to the field

eventually reaches the water body. The main mechanism of transport from the

field to the water body is by runoff (51.4% of the total transport), followed

by erosion (34.5%) and spray drift (14.1%).

In the water body, pesticide dissipates with an effective water column halflife of 4.2 days. (This value does not include dissipation by transport to

the benthic region; it includes only processes that result in removal of

pesticide from the complete system.) The main source of dissipation in the

water column is volatilization (effective average half-life = 4.3 days)

followed by metabolism (119 days).

In the benthic region, pesticide is stable. The vast majority of the

pesticide in the benthic region (99.29%) is sorbed to sediment rather than in

the pore water.

**Table 1. Estimated Environmental Concentrations (ppb) for d-limonene.**

Peak (1-in-10 yr) 0.239E+04

4-day Avg (1-in-10 yr) 0.164E+04

21-day Avg (1-in-10

yr) 762.

60-day Avg (1-in-10

yr) 353.

365-day Avg (1-in-10

yr) 73.0

Entire Simulation Mean 42.242

**Table 2. Summary of Model Inputs for d-limonene.**

**Scenario N**  **CSweetPotatoSTD**

**Cropped Area Fraction 1** 

**Koc (ml/g) 1**  **300**

**Water Half-Life (days) @ 25 °C 6**  **7.1**

**Benthic Half-Life (days) @ 25**

**°C 0** 

**Photolysis Half-Life (days) @**

**28 °Lat 0** 

**Hydrolysis Half-Life (days) 0** 

**Soil Half-Life (days) @ 25 °C 3**  **3**

**Foliar Half-Life (days) 0** 

**Molecular Wt 1**  **36.23**

**Vapor Pressure (torr) 2** 

**Solubility (mg/l) 1**  **3.8**

**Table 3. Application Schedule for d-limonene.**

Date (Days

Since

Emergence) Type Amount (kg/ha) Eff. Drift

1 Ground 38.75 0.99 0.017

3 Ground 38.75 .99 .017

5 Ground 38.75 .99 .017

7 Ground 38.75 .99 .017

9 Ground 38.75 .99 .017

11 Ground 38.75 .99 .017

13 Ground 38.75 .99 .017

15 Ground 38.75 .99 .017

17 Ground 38.75 .99 .017

19 Ground 38.75 .99 .017

21 Ground 38.75 .99 .017

23 Ground 38.75 .99 .01743

**Figure 1. Yearly Peak Concentrations**44

**PRZM/EXAMS (PE5)**

**Without volatilization**

stored as NJnurse.out

Chemical: d-limonene

PRZM environment: NJnurserySTD_V2.txt modified Sunday, 30 September 2007 at 23:05:00

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 13:47:26

Metfile: w93730.dvf modified Wedday, 3 July 2002 at 10:05:58

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 430 413 375 261 208 55.58

1962 816 641 351 176 157 42.45

1963 582 560 450 359 266 70.93

1964 565 412 273 142 104 28.34

1965 687 505 400 233 168 44.49

1966 2010 1920 1550 810 584 156

1967 277 211 157 131 107 30.14

1968 1650 1600 1420 1040 739 195

1969 634 605 407 203 144 38.24

1970 379 309 278 159 111 30.31

1971 653 489 368 307 217 57.74

1972 509 379 223 139 106 28.75

1973 1300 918 377 179 127 34.21

1974 163 137 117 55.81 45.64 12.95

1975 536 398 261 137 99.3 26.98

1976 958 741 560 316 218 58.29

1977 1250 1220 1110 534 380 100

1978 1930 1850 1560 1170 848 225

1979 1650 1220 667 537 395 106

1980 528 511 465 360 263 72.28

1981 313 300 267 165 117 32.31

1982 988 943 661 352 249 65.93

1983 282 242 164 92.55 72.74 21.59

1984 600 578 414 238 194 52.56

1985 375 297 272 159 110 30.61

1986 1660 1250 552 250 184 52.04

1987 888 862 754 555 400 108

1988 852 832 625 328 232 61.58

1989 243 199 141 78.3 60.21 16.84

1990 202 151 110 59.36 41.59 12.22

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 2010 1920 1560 1170 848 225

0.0645161290322581 1930 1850 1550 1040 739 195

0.0967741935483871 1660 1600 1420 810 584 156

0.129032258064516 1650 1250 1110 555 400 108

0.161290322580645 1650 1220 754 537 395 106

0.193548387096774 1300 1220 667 534 380 100

0.225806451612903 1250 943 661 360 266 72.28

0.258064516129032 988 918 625 359 263 70.93

0.290322580645161 958 862 560 352 249 65.93

0.32258064516129 888 832 552 328 232 61.58

0.354838709677419 852 741 465 316 218 58.29

0.387096774193548 816 641 450 307 217 57.74

0.419354838709677 687 605 414 261 208 55.58

0.451612903225806 653 578 407 250 194 52.56

0.483870967741936 634 560 400 238 184 52.04

0.516129032258065 600 511 377 233 168 44.49

0.548387096774194 582 505 375 203 157 42.45

0.580645161290323 565 489 368 179 144 38.24

0.612903225806452 536 413 351 176 127 34.21

0.645161290322581 528 412 278 165 117 32.31

0.67741935483871 509 398 273 159 111 30.61

0.709677419354839 430 379 272 159 110 30.31

0.741935483870968 379 309 267 142 107 30.14

0.774193548387097 375 300 261 139 106 28.75

0.806451612903226 313 297 223 137 104 28.34

0.838709677419355 282 242 164 131 99.3 26.98

0.870967741935484 277 211 157 92.55 72.74 21.59

0.903225806451613 243 199 141 78.3 60.21 16.8445

0.935483870967742 202 151 117 59.36 45.64 12.95

0.967741935483871 163 137 110 55.81 41.59 12.22

0.1 1659 1565 1389 784.5 565.6 151.2

Average of yearly averages: 62.2453333333333

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: NJnurse

Metfile: w93730.dvf

PRZM scenario: NJnurserySTD_V2.txt

EXAMS environment file: pond298.exv

Chemical Name: d-limonene

Description Variable Name Value Units Comments

Molecular weight mwt 136.23 g/mol

Henry's Law Const. henry 2.6e-2 atm-m^3/mol

Vapor Pressure vapr 2 torr

Solubility sol 13.8 mg/L

Kd Kd mg/L

Koc Koc 1300 mg/L

Photolysis half-life kdp 0 days Half-life

Aerobic Aquatic Metabolism kbacw 67.1 days Halfife

Anaerobic Aquatic Metabolism kbacs 0 days Halfife

Aerobic Soil Metabolism asm 33.53 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 1 integer See PRZM manual

Incorporation Depth: DEPI cm

Application Rate: TAPP 38.75 kg/ha

Application Efficiency: APPEFF 0.99 fraction

Spray Drift DRFT 0.017 fraction of application rate applied to pond

Application Date Date 01-01 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 2 days Set to 0 or delete line for single app.

app. rate 1 apprate 38.75 kg/ha

Interval 2 interval 2 days Set to 0 or delete line for single app.

app. rate 2 apprate 38.75 kg/ha

Interval 3 interval 2 days Set to 0 or delete line for single app.

app. rate 3 apprate 38.75 kg/ha

Interval 4 interval 2 days Set to 0 or delete line for single app.

app. rate 4 apprate 38.75 kg/ha

Interval 5 interval 2 days Set to 0 or delete line for single app.

app. rate 5 apprate 38.75 kg/ha

Interval 6 interval 2 days Set to 0 or delete line for single app.

app. rate 6 apprate 38.75 kg/ha

Interval 7 interval 2 days Set to 0 or delete line for single app.

app. rate 7 apprate 38.75 kg/ha

Interval 8 interval 2 days Set to 0 or delete line for single app.

app. rate 8 apprate 38.75 kg/ha

Interval 9 interval 2 days Set to 0 or delete line for single app.

app. rate 9 apprate 38.75 kg/ha

Interval 10 interval 2 days Set to 0 or delete line for single app.

app. rate 10 apprate 38.75 kg/ha

Interval 11 interval 2 days Set to 0 or delete line for single app.

app. rate 11 apprate 38.75 kg/ha

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)

**PRZM/EXAMS (PE5)**

**With Volatilization**

**Diffusion In Air Coefficient DAIR = 4300 cm 2**  **/day**

**Enthalpy of Vaporizaton = 10.48 kcal/mole**

stored as NJnurseV.out

Chemical: d-limonene

PRZM environment: NJnurserySTD_V2.txt modified Sunday, 30 September 2007 at 23:05:00

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 13:47:26

Metfile: w93730.dvf modified Wedday, 3 July 2002 at 10:05:58

Water segment concentrations (ppb)46

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 325 311 272 147 102 26.56

1962 127 110 100 49.06 33.74 8.762

1963 310 296 265 206 148 38.9

1964 106 84.75 76.44 35.12 24.1 6.27

1965 309 297 255 129 88.58 23.06

1966 313 300 267 209 150 39.45

1967 129 112 97.4 59.61 43.14 11.36

1968 320 306 274 214 152 39.79

1969 316 302 257 124 84.67 21.89

1970 309 295 255 128 88.41 22.98

1971 315 302 262 138 94.86 24.73

1972 125 108 94.67 46.4 31.76 8.227

1973 120 103 90.31 43.45 29.72 7.693

1974 123 106 93.01 44.55 30.37 7.842

1975 117 98.19 87.38 41.25 28.23 7.309

1976 317 304 264 137 94.51 24.67

1977 319 305 265 137 93.87 24.44

1978 339 327 294 228 164 43.44

1979 138 114 87.84 51.58 36.9 9.693

1980 314 300 269 210 150 39.7

1981 311 297 257 137 94.57 24.67

1982 324 310 265 141 97.49 25.52

1983 130 112 98.22 48.6 33.4 8.721

1984 309 297 256 133 91.87 23.94

1985 309 295 255 135 92.71 24.18

1986 124 107 94.16 47.12 32.5 8.508

1987 318 305 272 211 152 40.09

1988 315 302 260 137 94.79 24.7

1989 129 112 97.92 48.25 33.25 8.687

1990 120 103 90.7 43.72 30.03 7.813

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 339 327 294 228 164 43.44

0.0645161290322581 325 311 274 214 152 40.09

0.0967741935483871 324 310 272 211 152 39.79

0.129032258064516 320 306 272 210 150 39.7

0.161290322580645 319 305 269 209 150 39.45

0.193548387096774 318 305 267 206 148 38.9

0.225806451612903 317 304 265 147 102 26.56

0.258064516129032 316 302 265 141 97.49 25.52

0.290322580645161 315 302 265 138 94.86 24.73

0.32258064516129 315 302 264 137 94.79 24.7

0.354838709677419 314 300 262 137 94.57 24.67

0.387096774193548 313 300 260 137 94.51 24.67

0.419354838709677 311 297 257 137 93.87 24.44

0.451612903225806 310 297 257 135 92.71 24.18

0.483870967741936 309 297 256 133 91.87 23.94

0.516129032258065 309 296 255 129 88.58 23.06

0.548387096774194 309 295 255 128 88.41 22.98

0.580645161290323 309 295 255 124 84.67 21.89

0.612903225806452 138 114 100 59.61 43.14 11.36

0.645161290322581 130 112 98.22 51.58 36.9 9.693

0.67741935483871 129 112 97.92 49.06 33.74 8.762

0.709677419354839 129 112 97.4 48.6 33.4 8.721

0.741935483870968 127 110 94.67 48.25 33.25 8.687

0.774193548387097 125 108 94.16 47.12 32.5 8.508

0.806451612903226 124 107 93.01 46.4 31.76 8.227

0.838709677419355 123 106 90.7 44.55 30.37 7.842

0.870967741935484 120 103 90.31 43.72 30.03 7.813

0.903225806451613 120 103 87.84 43.45 29.72 7.693

0.935483870967742 117 98.19 87.38 41.25 28.23 7.309

0.967741935483871 106 84.75 76.44 35.12 24.1 6.27

0.1 323.6 309.6 272 210.9 151.8 39.781

Average of yearly averages: 21.1198333333333

Inputs generated by pe5.pl - Novemeber 200647

Data used for this run:

Output File: NJnurseV

Metfile: w93730.dvf

PRZM scenario: NJnurserySTD_V2.txt

EXAMS environment file: pond298.exv

Chemical Name: d-limonene

Description Variable Name Value Units Comments

Molecular weight mwt 136.23 g/mol

Henry's Law Const. henry 2.6e-2 atm-m^3/mol

Vapor Pressure vapr 2 torr

Solubility sol 13.8 mg/L

Kd Kd mg/L

Koc Koc 1300 mg/L

Photolysis half-life kdp 0 days Half-life

Aerobic Aquatic Metabolism kbacw 67.1 days Halfife

Anaerobic Aquatic Metabolism kbacs 0 days Halfife

Aerobic Soil Metabolism asm 33.53 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 1 integer See PRZM manual

Incorporation Depth: DEPI cm

Application Rate: TAPP 38.75 kg/ha

Application Efficiency: APPEFF 0.99 fraction

Spray Drift DRFT 0.017 fraction of application rate applied to pond

Application Date Date 01-01 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 2 days Set to 0 or delete line for single app.

app. rate 1 apprate 38.75 kg/ha

Interval 2 interval 2 days Set to 0 or delete line for single app.

app. rate 2 apprate 38.75 kg/ha

Interval 3 interval 2 days Set to 0 or delete line for single app.

app. rate 3 apprate 38.75 kg/ha

Interval 4 interval 2 days Set to 0 or delete line for single app.

app. rate 4 apprate 38.75 kg/ha

Interval 5 interval 2 days Set to 0 or delete line for single app.

app. rate 5 apprate 38.75 kg/ha

Interval 6 interval 2 days Set to 0 or delete line for single app.

app. rate 6 apprate 38.75 kg/ha

Interval 7 interval 2 days Set to 0 or delete line for single app.

app. rate 7 apprate 38.75 kg/ha

Interval 8 interval 2 days Set to 0 or delete line for single app.

app. rate 8 apprate 38.75 kg/ha

Interval 9 interval 2 days Set to 0 or delete line for single app.

app. rate 9 apprate 38.75 kg/ha

Interval 10 interval 2 days Set to 0 or delete line for single app.

app. rate 10 apprate 38.75 kg/ha

Interval 11 interval 2 days Set to 0 or delete line for single app.

app. rate 11 apprate 38.75 kg/ha

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)48

Appendix 5. TREX Model Sample Input/Output

INPUT

Table 1. Input

‐ Orange Guard (4.6 lb a.i./A)

Chemical Name: d

‐ limonene

Use 0

Formulation Orange Guard

Application Rate 4.6 lb a.i./acre

Half

‐ life 35 days

Application Interval 7 days

Maximum # Apps./Year 6

Length of Simulation 1 year

Variable application rates? no

Endpoints

Avian Bobwhite quail LD50 (mg/kg

‐ bw) 0.00

Bobwhite quail LC50 (mg/kg

‐ diet) 5600.00

Mallard duck NOAEL(mg/kg

‐ bw) 0.00

Bobwhite quail NOAEC (mg/kg

‐ diet) 0.00

Mammals LD50 (mg/kg

‐ bw) 4400.00

LC50 (mg/kg

‐ diet) 0.00

NOAEL (mg/kg

‐ bw) 250.00

NOAEC (mg/kg

‐ diet) 5000.00

Output

Table 2. Upper Bound Kenaga, Subacute Avian Dietary Based Risk Quotients

‐ Orange Guard (4.6 lb a.i./A)

(For Characterization

‐ non

‐ definitive endpoint)

LC50 EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/

Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

5600 4816.21 0.86 2207.43 0.39 2709.12 0.48 301.01 0.05 1886.35 0.3449

Table 3. Upper Bound Kenaga, Acute Mammalian Dose

‐ Based Risk Quotients

‐ Orange Guard (4.6 lb a.i./A)

Size

Class

(grams) Adjusted

LD50 EECs and RQs

Short Grass Tall Grass Broadleaf

Plants Fruits/Pods/

Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 9670 4592 0.47 2105 0.22 2583 0.27 287 0.03 1798 0.19 64 0.01

35 7824 3174 0.41 1455 0.19 1785 0.23 198 0.03 1243 0.16 44 0.01

1000 3384 736 0.22 337 0.10 414 0.12 46 0.01 288 0.09 10 0.00

Table 4. Upper Bound Kenaga, Chronic Mammalian Dose

‐ Based Risk Quotients

‐ Orange Guard (4.6 lb a.i./A)

Size

Class

(g) Adjusted

NOAEL EECs and RQs

Short Grass Tall Grass Broadleaf

Plants Fruits/Pods/

Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 549.5 4592 8.36 2105 3.83 2583 4.70 287 0.52 1798 3.27 64 0.12

35 444.6 3174 7.14 1455 3.27 1785 4.02 198 0.45 1243 2.80 44 0.10

1000 192.3 736 3.83 337 1.75 414 2.15 46 0.24 288 1.50 10 0.05

Input

Table 5. Input

‐ Orange Guard (4.6 lb a.i./A with 2 day foliar dissipation half

‐ life)

Chemical Name: d

‐ limonene

Use 0

Formulation Orange Guard

Application Rate 4.6 lb a.i./acre

Half

‐ life 2 days

Application Interval 7 days

Maximum # Apps./Year 6

Length of Simulation 1 year

Variable application rates? no

Endpoints

Avian Bobwhite quail LD50 (mg/kg

‐ bw) 0.00

Bobwhite quail LC50 (mg/kg

‐ diet) 5600.00

Mallard duck NOAEL(mg/kg

‐ bw) 0.00

Bobwhite quail NOAEC (mg/kg

‐ diet) 0.00

Mammals LD50 (mg/kg

‐ bw) 4400.00

LC50 (mg/kg

‐ diet) 0.00

NOAEL (mg/kg

‐ bw) 250.00

NOAEC (mg/kg

‐ diet) 5000.0050

Table 6. Upper Bound Kenaga, Subacute Avian Dietary Based Risk Quotients

‐ (4.6 lb a.i./A

‐ 2

‐ day for characterization )

LC50 EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

5600 1211.04 0.22 555.06 0.10 681.21 0.12 75.69 0.01 474.32 0.08

Table 7. Upper Bound Kenaga, Acute Mammalian Dose

‐ Based Risk Quotients

(4.6 lb a.i./A

‐ 2

‐ day for characterization )

Size

Class

(grams) Adj.

LD50 EECs and RQs

Short Grass Tall Grass Broadleaf

Plants Fruits/Pods/

Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 9670 1155 0.12 529 0.05 649 0.07 72 0.01 452 0.05 16 0.002

35 7824 798 0.10 366 0.05 449 0.06 50 0.01 313 0.04 11 0.001

1000 3384 185 0.05 85 0.03 104 0.03 12 0.00 72 0.02 3 0.001

Table 8. Upper Bound Kenaga, Chronic Mammalian Dose

‐ Based Risk Quotients

(4.6 lb a.i./A

‐ 2

‐ day for characterization )

Size

Class

(grams) Adjusted

NOAEL EECs and RQs

Short Grass Tall Grass Broadleaf

Plants Fruits/Pods/

Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 549 1155 2.10 529 0.96 649 1.18 72 0.13 452 0.82 16 0.03

35 445 798 1.80 366 0.82 449 1.01 50 0.11 313 0.70 11 0.02

1000 192 185 0.96 85 0.44 104 0.54 12 0.06 72 0.38 3 0.0151

Appendix 6. Terr Plant Model Input/output

Table 1. Chemical Identity.

Chemical Name Limonene

Use Christmas tree plantation

Application Method Ground

Application Form Spray

Solubility in Water

(ppm) 13

Table 2. Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 55.2 Lb/A

Incorporation I 1 none

Runoff Fraction R 0.02 none

Drift Fraction D 0.01 none

Table 3. EECs for Limonene. Units in lb /A.

Description EEC

Runoff to dry areas (A/I)*R 1.104

Runoff to semi

‐ aquatic areas (A/I)*R*10 11.04

Spray drift A*D 0.552

Total for dry areas ((A/I)*R)+(A*D) 1.656

Total for semi

‐ aquatic areas ((A/I)*R*10)+(A*D) 11.592

Table 4. Plant survival and growth data used for RQ derivation. Units are in lb /A.

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC

Monocot x x 2.83 0.19

Dicot x x 7.09 1.31

Table 5. RQ values for plants in dry and semi

‐ aquatic areas exposed to Limonene through runoff and/or

spray drift.*

Plant Type Listed Status Spray Drift

Monocot non

‐ listed 0.20

Monocot listed 2.91

Dicot non

‐ listed <0.1

Dicot listed 0.4252

Table 6. Chemical Identity.

Chemical Name Limonene

Use Variety of Ag Crops

‐ Burndown

Application Method Ground

Application Form Spray

Solubility in Water

(ppm) 13

Table 7. Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 34.6 lb/A

Incorporation I 1 none

Runoff Fraction R 0.02 none

Drift Fraction D 0.01 none

Table 8. EECs for Limonene. Units in lb/A.

Description Equation EEC

Runoff to dry areas (A/I)*R 0.692

Runoff to semi

‐ aquatic areas (A/I)*R*10 6.92

Spray drift A*D 0.346

Total for dry areas ((A/I)*R)+(A*D) 1.038

Total for semi

‐ aquatic areas ((A/I)*R*10)+(A*D) 7.266

Table 9. Plant survival and growth data used for RQ derivation. Units are in lb/A.

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC

Monocot x x 2.83 0.19

Dicot x x 7.09 1.31

Table 10. RQ values for plants in dry and semi

‐ aquatic areas exposed to Limonene through runoff and/or

spray drift.*

Plant Type Listed Status Dry Semi

‐ Aquatic Spray Drift

Monocot non

‐ listed #VALUE! #VALUE! 0.12

Monocot listed #VALUE! #VALUE! 1.82

Dicot non

‐ listed #VALUE! #VALUE! <0.1

Dicot listed #VALUE! #VALUE! 0.26

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.53

Table 11. Chemical Identity.

Chemical Name Limonene

Use Vine Crops

Application Method Ground

Application Form Spray

Solubility in Water

(ppm) 13

Table 12. Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 18.4 lb/A

Incorporation I 1 none

Runoff Fraction R 0.02 none

Drift Fraction D 0.01 none

Table 13. EECs for Limonene. Units in lb/A.

Description Equation EEC

Runoff to dry areas (A/I)*R 0.368

Runoff to semi

‐ aquatic areas (A/I)*R*10 3.68

Spray drift A*D 0.184

Total for dry areas ((A/I)*R)+(A*D) 0.552

Total for semi

‐ aquatic areas ((A/I)*R*10)+(A*D) 3.864

Table 14. Plant survival and growth data used for RQ derivation. Units are in lb/A.

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC

Monocot x x 2.83 0.19

Dicot x x 7.09 1.31

Table 15. RQ values for plants in dry and semi

‐ aquatic areas exposed to Limonene through runoff and/or

spray drift.*

Plant Type Listed Status Dry Semi

‐ Aquatic Spray Drift

Monocot non

‐ listed #VALUE! #VALUE! <0.1

Monocot listed #VALUE! #VALUE! 0.97

Dicot non

‐ listed #VALUE! #VALUE! <0.1

Dicot listed #VALUE! #VALUE! 0.1454

Appendix 7. Sample Input/output for Ag Drift Analysis

(Examples entered for listed Monocots)

Table 1. Avenger Label

‐ Medium

‐ Course Droplet (34.6 lb a.i./A)

T able 2. Orange Guard Label

‐ Fine to Very Fine Droplet (4.6 lb a.i./A)55

Table 3. Orange Guard Label

‐ Fine to Very Fine Droplet (18.4 lb a.i./A)

Table 4. Orange Guard Label

‐ Fine to Very Fine Droplet (55.2 lb a.i./A)56

Appendix 8. References

Chickos, J.S. and Acree, W.E. 2003. Enthalpies of Vaporization of Organic and Organometallic Compounds

1880

‐ 2002.J. Phys. Chem. Ref. Data. 32:519

‐ 877

CICAD#5. 1998. Concise International Chemical Assessment Document 5. Limonene World Health

Organization Geneva, 1998. http://whqlibdoc.who.in t/publications/1998/9241530057.pdf

Clará, R.A., A.C. Gómez Marigliano, and H. Sólimo. 2009. Density, Viscosity, and Refractive Index in the

Range (283.15 to 353.15) K and Vapor Pressure of α‐ Pinene, d‐ Limonene, (±)

‐ Linalool, and Citral Over the

Pressure Range of 1.0 kPa Atmospheric Pressure. J. Chem. Eng. Data. 54:1087

‐ 1090.

Copolovici, L.O. and U. N iinemets. 2005. Temp erature dependancies of Henry’s Law constants and

octanol/water partition coefficients for key plant volatile monoterpenoids. Chemosphere 61:1390

‐ 1400.

FFHPVC. The Flavor and Fragrance High Production Volume Consortium.

http://www.epa.gov/hpv/pubs/su mmaries/monoterp/c13756rr.pdf

Hayward, S., R.J. Muncey, A.E. James, C.J. Halsall, and C.N. Hewitt., 2011. Monoterpene emissions from

soil in a Sitka spruce forest. Atm o spheric Environment. 35:4081

‐ 4087.

IPCS, 1998. International Program on Chemical Safety. Concise International Chemical Assessment No.

5.World Health Organization, Geneva, 1998.

http://www.inchem.org/documents/cicads/cicads/cicad05.htm

Leff, J.W. and N. Fierer. 2008. Volatile organic compound (VOC) emissions from soil and litter samples.

Soil Biology & Chemistry. 40:1629

‐ 1636.

Li, J., E.M. Perdue, S.G. Pavlostathis, and R. Araujo. 1998. Physicochemical Properties of Selected

Monoterpenes. Environmental International. 24:353

‐ 358.

Massaldi, H.A. and C.J. King, 1973. Simple Technique to Determine Solubilities of Sparingly Soluble

Organics: Solubility and Activity Coefficients of d‐ lim onene, n‐ butylbenzene, and n‐ hexyl acetate in water

and sucrose. J. Chem. Eng. Data. 18:393

‐ 397.

Miller, D.J. and S.B. Hawthorne. 2000. Solubility of Liquid Flavor and Fragrance Compounds in Subcritical

(Hot/Liquid) Water from 298 K to 473 K. J. Chem. Eng. Dat a. 45:315

‐ 318.

Rifai, H. S., and C. J. Newell., 1998. Estimating First

‐ Order Decay Rates for BTEX Using Data from 115 Sites,

in Proceedings of the 1998 NGWA Conference on Petroleum Hydrocarbons and Organic Chemicals in

Ground Water: Prevention, Detection and Restoration, Nov. 11

‐ 13, Houston, Tex as, pp. 31

– 41, National

Ground Water Association, Westerville, OH.57

Rifai and Newell, 1998. https://info.ngwa.org/GWOL/pdf/982664575.PDF

TOXNET, 2006. Toxicology Data Network Limonene, National Library of Medicine (NLH. Hazardous

Substances Data Bank (HSDB). Bethesda, MD. http://toxnet.nlm.nih.gov/cgi

‐

bin/sis/search/a?dbs+hsdb:@term+@DOCNO+1809