July 24, 2014 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

SUBJECT: PC Code: 879709; Sweet Orange Peel Tincture; Human Health Risk 

Assessment and Ecological Effects Assessment to Support Proposed 

Exemption from the Requirement of a Tolerance When Used as Inert 

Ingredients in Pesticide Formulations. 

All PC Code: 879709 

Decision No.: N/A 

DP Barcode: N/A 

Regulatory Action: Inert 

Tolerance Exemption; 40 

CFR 180.910. 

Petition No: IN-10547 All CAS Reg. No: 8028-

48-6 

Inert Tracking No: N/A 

FROM: Lisa Austin, Ph.D., Toxicologist ) 

Inert Ingredient Assessment Branch (IIAB) ~.ra--_,_ __ _ 

Registration Division (7505P) 

THROUGH: Kerry Leifer, Team Leader ~ .rt--

Inert Ingredient Assessment Branch (IIAB) h L 

Registration Division (7505P) . L 

TO: PV Shah, Ph.D., Branch Chief 

Inert Ingredient Assessment Branch (IIAB) 

Registration Division (7505P) 
EXECUTIVE SUMMARY 

EPA received a petition (PP#IN-10547) from AG-Chem Consulting (12208 Quinque Lane, 

Clifton VA 21 024), on behalf of Oro-Agri, Inc.(990 Trophy Club Drive, Trophy Club TX 76262) 

requesting an exemption from the requirement of a tolerance for sweet orange peel tincture (CAS 

Reg. No. 8028-48-6) for use as a surfactant, fragrance and adjuvant inert ingredient up to 10% 

concentration in pesticide products on all pre- and post-harvest food commodities under 40 CFR 

part 180.910. EPA published the notice of filing (NO F) for this petition in the Federal Register 

on July 19, 2013 (78 FR 43117). No comments were received in response to this notice. 

Sweet orange peel tincture and sweet orange peel oil are chemi~ally the same (EINECS No. 

232-433-8; CAS 8028-48-6). The only difference is the method of extraction. Sweet orange 

peel tincture is extracted in alcohol and the extraction process leads to the formation of a 

"tincture". Sweet orange peel oil is extracted by cold press expression. Both are extracted from 

the same plant, Citrus sinensis family Rutaceae. Both forms of the sweet orange peel extract 

contain d-limonene as its primary component(> 90 %) and lesser amounts ofmyrcene. The 

EPA has conducted a "Screening-Level Hazard Assessment" of a class of compounds called 

monoterpene hydrocarbons, d-limonene and myrcene are among the monoterpene hyrdrocarbons 

assessed. The chemical class was "based on structural similarity, similar molecular weights and 

functional groups and the expectation that inherent physicochemical, environmental and 

toxicological properties are predicted to be similar". That analysis also included a review of data 

on sweet orange peel oil since it is a complex mixture containing greater than 90% monoterpene 

hydrocarbons (including d-limonene and myrcene ), and is expected to have "physicochemical, 

environmental and toxicological properties similar to the major components .. .limonene and 

myrcene". Therefore, the Agency assessed the potential toxicity of sweet orange peel tincture 

based on the available toxicity data for sweet orange peel oil, and where data for sweet orange 

peel oil is missing, relied upon available data for the monoterpene hydrocarbons chemical class. 

The acute oral and dermal toxicity of sweet orange peel. oil is low. The oral LD50 was 

>5,000 mg/kg in rats and rabbits, respectively. 

In a 28-day study with sweet orange peel oil, lesions in the non-glandular stomach and 

clinical chemistry were observed at 1,500 mg!kg/day (above the limit dose of 1,000 mg/kg/day) 

in rats. Lesions in the non-glandular stomach is attributed to the irritating property of the 

chemical. The NOAEL was 600 mg/kg/day. 

In a combined reproductive/developmental toxicity screening test with sweet orange peel oil, 

stillbirths and pup mortality were observed at 1,500 mg!kg/day. The offspring NOAEL was 750 

mg/kg/day. Signs of toxicity were not observed in maternal rats, the NOAEL was 1,500 

mg/kg/day. 

2 
Evidence of mutagenicity was not observed in the Ames test. Although, evidence of 

mutagenicity was observed in mouse lymphoma assay, it was noted that cytotoxic concentrations 

were not reported and this could contribute to an inflated mutation rate. In addition, d-limonene 

was not mutagenic in an Ames test, mouse lymphoma, sister chromatid exchange nor in 

chromosome aberrations in Chinese hamster ovary cells assays. Therefore, based on the weight 

of evidence sweet orange peel tincture is not expected to be mutagenic. 

Evidence of immunotoxicity was not observed. Sweet orange peel oil exhibited no effects on 

cell-mediated or humoral immune response at doses up to 2,500 mglkg/day in a plaque-forming 

cell assay in mice. 

Although a carcinogenicity study was not available for sweet oi:ange peel tincture, 

carcinogenicity studies were available in the rat and mouse for d-limonene. An increased 

incidence of tumor formation was not observed in a 2 year carcinogenicity study on female rats 

or in male and female mice treated with d-limonene up to 1,000 mg/kg/day. An increased 

incidence of tubular cell hyperplasia, adenomas, and adenocarcinomas of the kidney was 

observed in the male rat. However, these lesions are related to the accumulation of the alpha 2uglobulin protein which is specific to the male rat and is not relevant for human risk assessment. 

EPA has determined that reliable data show the safety of infants and children would be 

adequately protected if the FQPA SF were reduced to IX. 

Available toxicity data on sweet orange peel oil demonstrated effects at 1,500 mg/kg/day and 

no toxicity at doses up to 600 mg/kg/day. Therefore, since there are no endpoints of concern for 

sweet orange peel tincture a qualitative dietary exposure risk assessment is appropriate. 

Sweet orange peel tincture is used as an inert ingredient in pesticide products that could 

result in residential exposure. However., based on the lack oftoxicity, a quantitative exposure 

assessment from "residential exposures" was not performed. 

The Agency believes that amending the tolerance exemption to include 40 CFR § 180.910 

will not significantly/measurably increase occupational exposure. The change in use pattern 

would be expanded to include use as a surfactant, fragrance and adjuvant inert ingredient up to 

10% concentration in pesticide products on all pre- and post-harve~t food commodities. Based 

on the absence of toxicity of sweet orange peel tincture, it is not necessary to quantitatively 

assess occupational exposure. 

Ecotoxicity and fate and effects data were not available for sweet orange peel tincture. 

However, limited data is available for d-limonene. The acute toxicity of d-limonene ranges from 

slight to high for aquatic organisms. It caused moderate acute toxicity in insects and mites. It 

was biodegradable. 

Potential areas of environmental justice concerns, to the extent possible, were considered in 

this human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal 

Actions to Address Environmental Justice in Minority Populations and Low-Income 

Populations," http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf. 

3 
Taking into consideration all available information on sweet orange peel tincture (CAS Reg. 

No. 8028-48-6), EPA concludes that there is a reasonable certainty that no harm will result to the 

general population or to infants and children from aggregate exposure to sweet orange peel 

tincture. Therefore, the establishment of an .exemption from tolerance under 40 CFR 180.91 0 for 

residues of sweet orange peel tincture for use as a surfactant, fragrance and adjuvant inert 

ingredient up to 1 0% concentration when used as an inert ingredient in pesticide formulations in 

pre- and post-harvest food commodities in the end-product formulation can be considered safe 

under section 408 of the FFDCA. 

I. BACKGROUND 

On February 13, 2013 AG-Chem Consulting (12208 Quinque Lane, Clifton VA 21024), on 

behalf of Oro-Agri, Inc. (990 Trophy Club Drive, Trophy Club TX. 76262), submitted a petition 

(IN-1 0547) requesting an exemption from tolerance for sweet orange peel tincture (CAS Reg. 

Nos. 8028-48-6) when used as a surfactant, fragrance and adjuvant inert ingredient up to 10% 

concentration in pesticide products on all pre- and post-harvest food commodities under 40 CFR 

part 180.910. EPA published the Notice of Filing for this petition in the Federal Register on July 

19, 2013 (78 FR 43117). No comments were received in response to this notice. 

Currently, d-limonene is exempted from the requirement of a tolerance when used in 

accordance with good agricultural practice as a solvent or fragrance (or occasionally active as an 

insecticide, insect repellent, and animal (dog and cat repellent)) ingredients in pesticide 

formulations under 40 CFR 180.910 and 180.930. It is also approved under 40 CFR 180.539 for 

used in insect-repellent tablecloths and in insect-repellent strips used in food- or feed-handling 

establishments. It is also considered by FDA to be GRAS as a food additive when used as a 

synthetic flavoring substance and adjuvant (21 CFR 182.60). It is not registered for food or feed 

crop uses as an active ingredient, but can be used on compost and manure. 

This document provides an assessment of the risk to human health and the environment for 

for sweet orange peel tincture when used as an inert ingredient in pesticide formulations applied 

to pre- and post-harvest agricultural commodities. 

II. PHYSICAL AND CHEMICAL PROPERTIES 

Sweet orange peel tincture (CAS # 8028-48-6) is comprised of terpenes, aldehydes and 

alcohols all present in concentrations of <2%. The constituents of sweet orange peel tincture are 

found in Table 1 (V ora et.al., 1983). 

Table 1. Sweet Orange Peel Tincture (CAS # 8028-48-6) Constituents 

CAS# Constituents Typical 

Concentration (% 

w/w) 

5989-27-5 d-limonene >95% 

123-35-3 myrcene <2% 

4 
80-56-8 a-pinene <1% 

3387-41-5 Sabinene <1% 

99-83-2 Alpha-, Beta- <1% 

555-10-2 phellandrene(isomers) 

111-87-5 1-0ctanol <1% 

124-19-6 Nonanal <1% 

78-70-6 Linalool <1% 

106-23-0 Citronella! <1% 

98-55-5 a-Terpineol <1% 

112-3 1-2 Dec anal <1% 

106-26-3 Neral <1% 

14 1-27-5 Geranial <1% 

2111-75-3 Perillaldehyde <1% 

112-14-1 Octyl acetate <1% 

112-44-7 Undecanal <1% 

112-54-9 Dodecanal <1% 

13877-93-5 P-Caryophyllene <1% 

3856-25-5 P-Copaene <1% 

18794-84-8 P-F arnesene <1% 

4630-07-3 Valencene <1% 

3779-62-2 P-Sinensal <1% 

17909-77-2 a-Sinensal <1% 

4674-50-4 Nootkatone <1% 

Some. of the physical and chemical characteristics of sweet orange peel oil (CAS# 8008-

57 -9) are found in Table 2. 

Table 2. Physical and Chemical Properties of Sweet Orange Oil 

Parameter Value Source 

Structure Limonene: 91-94% 

Myrcene: 2.0-2.1% 

Chemical Name Sweet Orange Oil 

CAS # 8008-57-9 

Molecular Weight 

As cited in High Production Common Names Citrus sinensis oil 

Physical State liquid Volume 

SCREENING-LEVEL HAZARD -97 to -74°C (measured values for CHARACTERIZATION Melting Point (

0 C) limonene); <-l0°C (measured value for · Monoterpene Hydrocarbons myrcene) 

Boiling Point (0C) 167-l72°C (measured values for myrcene) Category 

1.43 at 20°C (measured value for 

Vapor Pressure (Pa at 20°C) limonene); 2.01 at 25°C (measured value 

for myrcene) 

Partition Coefficient (Kow) 4.57 (measured value for limonene); 4.47 

(measured value for terpinolene and sweet 

5 
orange oil); 4.1 7 (measured value for 

myrcene) 

Water Solubility (mg/liter at 13.8 at25°C (measured value for 

limonene); 5.6 at 25°C (measured value for 25°C) myrcene) 

Henry's Law Constant (kPa 0.032 (measured value for limonene); 

m3

/mol at 25 °C) 0.064 (measured value for myrcene) 

3. Hazard Assessment 

Sweet orange peel tincture and sweet orange peel oil are chemically the same (EINECS No. 

232-433-8; CAS 8028-48-6). The only difference is the method of extraction. Sweet orange 

peel tincture is extracted in alcohol and the extraction process leads to the formation of a 

"tincture". Sweet orange peel oil is extracted by cold press expression. Both are extracted from 

the same plant, Citrus sinensis family Rutaceae. Both forms of the sweet orange peel extract 

contain d-limonene as its primary component(> 90 %) and lesser amounts ofmyrcene. The 

EPA has conducted a "Screening-Level Hazard Assessment" of a class of compounds called 

monoterpene hydrocarbons, d-limonene and myrcene are among the monoterpene hyrdrocarbons 

assessed. The chemical class was "based on structural similarity, similar molecular weights and 

functional groups and the expectation that inherent physicochemical, environmental and 

toxicological properties are predicted to be similar". That analysis also included a review of data 

on sweet orange peel oil since it is a complex mixture containing greater than 90% monoterpene 

hydrocarbons (including d-limonene and myrcene ), and is expected to have "physicochemical, 

environmental and toxicological properties similar to the major components .. .limonene and 

myrcene". Therefore, the Agency assessed the potential toxicity of sweet orange peel tincture 

based on the available toxicity data for sweet orange peel oil, and where data for sweet orange 

peel oil is missing, relied upon available data for the monoterpene hydrocarbons chemical class. 

The following summaries were reproduced from the "Screening-Level Hazard Characterization; 

Monoterpene Hydrocarbons Category" (USEP A 2009). 

Sweet Orange Oil CCASRN 8008-57-9) 

Acute Toxicity Studies 

Table 3. Acute Toxicity Profile of Sweet Orange Peel Oil 

Toxicity 

Study Type Results Category 

Acute Oral - rat 

LD50 > 5000 mg/kg bw IV 

Acute Dermal - Rabbit LD50 > 5000 mg/kg bw IV 

Acute Oral Toxicity 

Wistar rats (10 males) were administered orange peel oil, sweet via gavage at 5000 mg/kg-bw 

and observed for 14 days. No deaths were reported. The LDso (male)> 5000 mg/kg-bw. 

6 
Acute Dermal Toxicity 

New Zealand White rabbits (1 0, sex not reported) were administered orange peel oil, sweet 

dermally at 5000 mg/kg-bw on to their clipped, abraded abdominal skin for 24 hours and observed 

for 7 days. There were no mortalities. The LDso > 5000 mg/kg-bw. 

Repeated Dose Studies 

28-Day Oral Toxicity Study-rat 

In a 28-day study, Sprague Dawley rats (10/sex/dose) were administered orange peel oq, 

sweet, in 1% methyl cellulose, via gavage at 0, 240, 600 or 1500 mg/kg-bw/day. No treatmentrelated effects were reported on survival, body weights or food consumption. Treatment-related 

decreases in glucose were observed in males at the high dose and in females at the mid- and high 

dose. Increases (significance not reported) in serum albumin and total serum protein were 

observed in all treated females and in the high dose males. Kidney and liver weights were 

increased in the treated male groups and in the high dose female groups. Treatment-related 

lesions were observed in the nonglandular stomach of the high dose males and females, and in 

the kidney of all treated males, characteristic of hyaline droplet formation and alpha2u-globulin 

accumulation. Nephropathy associated with alpha2u-globulin formation in male rats is not 

considered relevant to humans (US EPA, 1991). The LOAEL was 1500 mg/kg-bw/day based on 

lesions in the stomach and clinical chemistry. The NOAEL was 600 mglkg-bw/day. 

Reproductive/Developmental Toxicity-rat 

In a combined reproductive/developmental toxicity screening testj female Sprague-Dawley rats . 

(10/dose) were administered orange peel oil, sweet via gavage at 0, 375,750 or 1500 mg/kg/day for 7 

days prior to and through mating, gestation, delivery and four days of lactation. Treated animals had 

decreased weight gains, and significantly decreased absolute and relative food consumption at 750 

and 1500 mg/kg/day during the seven day pre-mating period. No treatment related effects on mating 

performance or fertility were observed at any dose level. A significant number of stillbirths and pup 

deaths were observed at 1500 mg/kg/day. No other treatment-related effects on offspring were 

observed. The maternal NOAEL was 1500 mglkg/day, the highest dose tested. The offspring 

LOAEL was 1500 mg/kg/day based on stillbirths and pup mortality. The offspring NOAEL 750 

mglkg/day. 

Mutagenicity 

In a reverse-mutation assay, Salmonella typhimurium strains TA98, TA100, TA1535, TA1537 or 

TA1538 were exposed to orange peel oil, sweet at 5000 f.!g/plate in the presence and absence of 

metabolic activation. No information on the use of positive controls and cytotoxic concentrations 

was provided. No evidence of mutagenic activity was reported at any concentration tested, with or 

without metabolic activation. 

In a forward mutation assay, mouse lymphoma L5178Y TK+/- cells were exposed to orange peel 

oil at concentrations ranging from 40 to 200 )lg/mL in the presence and absence of metabolic 

7 
activation. Increases in mutation were observed with and without metabolic activation. Cytotoxicity 

(concentration not stated) was also observed. This could contribute to an inflation of mutations. 

Immunotoxicity 

In a plaque-forming cell (PFC) assay, female B6C3Fl mice were administered orange peel oil via 

at gavage 0, 625, 1250 or 2500 mg/kg bw daily for 5 days to determine effects on humoral and cellmediated immune responses. A host resistance assay (Listeria monocytogenes bacterial challenge) 

was used to assess cell-mediated immunity while the antibody plaque forming cell response to sheep 

erythrocytes was used to measure humoral immunity. Body weights, lymphoid organ weights and 

spleen cellularity were also evaluated. In the absence of modulation of the PFC response, these 

effects were not considered as indicators of immunotoxicity. Orange oil had no effects on cellmediated or humoral immune response at any dose level tested. The NOAEL = 2500 mg/kg/day, the 

highest dose tested). 

Table 4. Toxicology Profile for Sweet Orange Oil 

Guideline No./ Study MRID No. (year)/ Results 

Type Classification /Doses 

28-week-Oral Toxicity 0, 240, 600 or 1500 NOAEL: 600 mglkglday Study- Rat-gavage mg/kglday LOAEL: 1500 mglkglday based on lesions in the stomach 

and clinical chemistry. 

Developmental Toxicity - 0, 250, 500 and 1000 Maternal NOAEL = 500 mglkglday. Sprague-Dawley rat - mglkg/day 

gavage Maternal LOAEL = I 000 mglkg/day based on reduced body 

weight, body weight gain, food consumption. 

Developmental NOAEL' = I 000 mglkg/day. 

Developmental LOAEL was not established. 

Reproduction/Development 0, 375, 750 or 1500 Maternal NOAEL = 1500 mglkg/day. 

a! Toxicity -Rat -gavage mglkglday Maternal LOAEL was not established. 

Developmental NOAEL = 750 mglkg/day. 

Developmental LOAEL = 1500 mg/kg/day based on on 

stillbirths and pup ort~lity. 

Ames Test 0 and 5000 ug/plate Negative. 

Mouse Lymphoma Assay 40-200 ug/ml Increases in mutation were observed with and without 

metabolic activation. Cytotoxicity (concentration not 

stated) was also observed. 

8 
Table 4. Toxicology Profile for Sweet Orange Oil 

Guideline No./ Study MRID No. (year)/ Results 

Type Classification /Doses 

Plaque-Forming Cell Assay 0, 625, 1250 or 2500 mglkg NOAEL: 2500 mg/kglday -Mice bw LOAEL was not established. 

D. Toxicity Endpoint Selection 

The available toxicity studies indicate that sweet orange peel tincture has low toxicity. These 

data demonstrated effects at 1500 mg/kg/day (above the limit dose) and no toxicity at doses up to 

600 mg/kg/day. Therefore, since no endpoint of concern was identified for sweet orange peel 

tincture, a qualitative risk assessment is appropriate. 

E. Special Considerations for Infants and Children 

Section 408 ofthe FFDCA provides that EPA shall apply an additional margin of safety for 

infants and children in the case of threshold effects to account for prenatal and post natal toxicity 

and the completeness of the database on toxicity and exposure unless EPA determines that a 

different margin of safety will be safe for infants and children . . EPA concludes that the FQP A 

safety factor could be reduced to 1X for sweet orange peel tincture for the following reasons: 

1. The database is considered adequate for FQPA assessment based on the toxicity 

information on sweet orange oil and d-limonene. The following acceptable studies are 

available: 

Subchronic (rat) 

Combined Reproductive/Developmental toxicity study (rat) 

Immunotoxicity study (rat) 

u. Quantitative fetal susceptibility was observed in combined reproduction/developmental 

study with rats administered sweet orange peel oil. In rats, maternal toxicity was not 

observed at 1500 mg/kg/day (above 1000 mg!kg/day, the limit dose). Developmental 

effects (stillborn pups and pup mortality) were observed at 1500 mg/kg/day. However, 

there is no concern for these effects since they occur above the limit dose. 

111. Neurotoxicity studies were not available for review. However, signs of potential 

neurotoxicity were not observed in any of the submitted studies with sweet orange oil or 

d-limonene. EPA concluded that neither a neurotoxicity nor a developmental 

neurotoxicity study is required at this time. 

9 
iv. An immunotoxicity study was available for review. Evidence of immunotoxicity was not 

observed in a plaque-forming cell assay in mice treated with sweet orange oil. Therefore, 

EPA concluded that the immunotoxicity study is not required at this time. 

Taking into consideration the available information, EPA concludes the additional 1 OX 

FQPA safety factor can be reduced to IX. 

4. Exposure Assessment 

In evaluating dietary exposure to sweet orange peel tincture, EPA considered exposure under 

the petitioned for exemptions from the requirement of a tolerance. EPA assessed dietary 

exposures from sweet orange oil in food as follows: 

Dietary Exposure 

Dietary exposure can occur from eating foods containing residues of sweet orange peel 

tincture. Because no hazard endpoint of concern was identified for the acute and chronic dietary 

assessment (food and drinking water), a quantitative dietary exposure risk assessment was not 

conducted. 

Residential Exposure (non-dietary exposure) 

The term "residential exposure" is used in this document to refer to non-occupational, nondietary exposure (e.g., textiles (clothing and diapers), carpets, swimming pools, and hard surface 

disinfection on walls, floors, tables). Sweet orange peel tincture is used as an inert ingredient in 

pesticide products that could result in short- and intermediate-term residential exposure. 

However, based on the lack of toxicity, a quantitative exposure assessment from residential 

exposures was not performed, 

5. Aggregate Risk 

Based on the lack of any endpoints of concern, EPA concludes that there is a reasonable 

certainty that no harm will result to the general population or to infants and children from 

aggregate exposure to sweet orange peel tincture residues. 

6. Occupational Exposure/Risk Pathway 

The Agency believes that amending the tolerance exemption to include 40 CFR § 180.910 

will not significantly/measurably increase occupational exposure. The change in use pattern 

would be expanded to include use as a surfactant, fragrance and adjuvant inert ingredient up to 

10% concentration in pesticide products on all pre- and post-harvest food commodities. Based 

on the regulatory history of d-limonene, the major component of sweet orange peel tincture and 

no new toxicological information to indicate otherwise, it is not necessary to quantitatively 

assess occupational exposure. 

10 
7. Cumulative Exposure: 

Section 408(b)(2)(D)(v) ofFFDCA requires that, when considering whether to establish, 

modify, or revoke a tolerance, the EPA consider "available information" concerning the 

cumulative effects of a particular pesticide's residues and "other substances that have a common 

mechanism of toxicity." Unlike other pesticides for which EPA has followed a cumulative risk 

approach based on a common mechanism of toxicity, EPA has not found sweet orange peel 

tincture to share a common mechanism of toxicity with any other substances and sweet orange 

peel tincture does not appear to produce a toxic metabolite produced by other substances. The 

major component of sweet orange peel tincture is d-limonene. An endpoint of concern was not 

identified for d-limonene in various dietary and non-dietary exposure scenarios. Additionally, the 

risk to aggregate exposure of d-limonene was below the Agency's concern. For information 

regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity 

and to evaluate the cumulative effects of such chemicals, see the policy statements released by 

EPA's Office of Pesticide Programs concerning common mechanism determinations and 

procedures for cumulating effects from substances found to have a common mechanism on 

EPA's website at http://www.epa.gov/pesticides/cumulative/. 

8. Environmental Fate 

The environmental fate summary was reproduced from International Programme on chemical 

Safety's Concise International Chemical Assessment Document No. 5 Limonene (1998). 

Limonene was completely biodegraded in 8 days in a laboratory study using unacclimated 

soil obtained from a coniferous forest. It was also shown to be readily biodegradable using the 

modified MITI test (OECD 301 C)(Limonene (CICADS)). 

Ecotoxicity 

Ecotoxicity summary was reproduced from International Programme on chemical Safety's 

Concise International Chemical Assessment Document No. 5 Limonene (1998). 

Aquatic envirorunent 

The acute toxicity of d-limonene ranges from slight to high for aquatic organisms. The 

lowest acute toxicity values (EC50 or LC50) identified were approximately 0.4 mg/litre for 

Daphnia (US EPA, 1990b) and 0. 7 mg/litre for fish. The no-observed-effect concentration 

(NOEC) for green algae is approximately 4 mg/litre. The acute toxicity (EC50 or LC50) of 

dipentene to Daphnia and fish is about 50-70 times lower than that for d-limonene. No studies 

were identified on the chronic toxicity of limonene to aquatic organisms. 

Terrestrial environment 

Limonene generally has moderate acute toxicity in insects and mites. The acute toxicity of dlimonene to earthworms (Eiseniafoetida Savigny) was high (LC50 = 6.0 ppm; mg/kg) . 

. 11 
Sublethal effects (i.e. abnormal rebounding of medial giant fibre pathway [MGF] impulses and 

spontaneous lateral giant fibre pathway [LGF] spiking) were observed following exposure of 

earthworms to 4.2 ppm (mg/kg) limonene. Limonene has low subacute toxicity to bobwhite 

quail (Colinus virginianus) exposed via the diet (LC50 > 5620 ppm; mg/kg). 

9. Analytical Methods 

Analytical methods are not available for residue measurement. 

10. Environmental Justice 

Potential areas of environmental justice concerns, to the extent possible, were considered in 

this human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal 

Actions to Address Environmental Justice in Minority Populations and Low-Income 

Populations," http://www.eh.doe.gov/oepalguidance/justice/eol2898.pdf). 

As a part of every pesticide risk assessment, OPP considers a large variety of consumer 

subgroups according to well-established procedures. In line with OPP policy, HED estimates 

risks to population subgroups from pesticide exposures that are based on patterns of that 

subgroup's food and water consumption, and activities in and around the home that involve 

pesticide use in a residential setting. Extensive data on food consumption patterns are compiled 

by the USDA under the Continuing Survey of Food Intake by Individuals (CSFII) and are used 

in pesticide risk assessments for all registered food uses of a pesticide. These data are analyzed 

and categorized by subgroups based on age, season ofthe year, ethnic group, and region of the 

country. Additionally, OPP is able to assess dietary exposure to smaller, specialized subgroups 

and exposure assessments are performed when conditions or circumstances warrant. Whenever 

appropriate, non-dietary exposures based on home use of pesticide products and associated risks 

for adult applicators and for toddlers, youths, and adults entering or playing on treated areas 

post-application are evaluated. Further considerations are currently in development as OPP has 

committed resources and expertise to the development of specialized software and models that 

consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary 

patterns among specific subgroups. 

11. Human Studies 

This assessment relies in part on data from studies in which adult human subjects were 

intentionally exposed to a pesticide. These studies, listed below, have received the appropriate 

ethical review for use in risk assessment. 

The PHED Task Force, 1998. The Pesticide Handler Exposure Database (PHED), Version 

1.1. Task Force members: Health Canada, U.S. Environmental Protection Agency, the 

California Department of Pesticide regulation, and the American Crop Protection Association; 

released August 1998. 

12. Risk Characterization 

12 
Sweet orange peel tincture and sweet orange peel oil are chemically the same (EINECS No. 

232-433-8; CAS 8028-48-6). The only difference is the method of extraction. Sweet orange 

peel tincture is extracted in alcohol and the extraction process leads to the formation of a 

"tincture". Sweet orange peel oil is extracted by cold press expression. Both are extracted from 

the same plant, Citrus sinensis family Rutaceae. Both forms of the sweet orange peel extract 

contain d-limonene as its primary component(> 90 %) and lesser amounts ofmyrcene. The 

EPA has conducted a "Screening-Level Hazard Assessment" of a class of compounds called 

monoterpene hydrocarbons, d-limonene and myrcene are among the monoterpene -hyrdrocarbons 

assessed. The chemical class was "based on structural similarity, similar molecular weights and 

functional groups and the expectation that inherent physicochemical, environmental and 

toxicological properties are predicted to be similar". That analysis also included a review of data 

on sweet orange peel oil since it is a complex mixture containing greater than 90% monoterpene 

hydrocarbons (including d-limonene and myrcene), and is expected to have "physicochemical, 

environmental and toxicological properties similar to the major components .. .limonene and 

myrcene". Therefore, the Agency assessed the potential toxicity of sweet orange peel tincture 

based on the available toxicity data for sweet orange peel oil, and where data for sweet orange 

peel oil is missing, relied upon available data for the monoterpene hydrocarbons chemical class. 

The acute oral and dermal toxicity of sweet orange peel oil is low. The oral LD50 was 

>5,000 mg/kg in rats and rabbits, respectively. 

In a 28-day study with sweet orange peel oil, lesions in the non-glandular stomach and 

clinical chemistry were observed at 1,500 mg/kg/day (above the limit dose of 1,000 mg/kg/day) 

in rats. Lesions in the non-glandular stomach is attributed to the irritating property of the 

chemical. The NOAEL was 600 mg/kg/day. 

In a combined reproductive/developmental toxicity screening test with sweet orange peel oil, 

stillbirths and pup mortality were observed at 1,500 mg/kg/day. The offspring NOAEL was 750 

mg/kg/day. Signs of toxicity were not observed in maternal rats, the NOAEL was 1,500 

mg/kg/day. 

Evidence of mutagenicity was not observed in the Ames test. Although, evidence of 

mutagenicity was observed in mouse lymphoma assay, it was noted that cytotoxic concentrations 

were not reported and this could contribute to an inflated mutation rate. In addition, d-limonene 

was not mutagenic in an Ames test, mouse lymphoma, sister chromatid exchange nor in 

chromosome aberrations in Chinese hamster ovary cells assays. Therefore, based on the weight 

of evidence sweet orange peel tincture is not expected to be mutagenic. 

Evidence of immunotoxicity was not observed. · Sweet orange peel oil exhibited no effects on 

cell-mediated or humoral immune response at doses up to 2,500 mg/kg/day in a plaque-forming 

cell assay in mice. 

Although a carcinogenicity study was not available for sweet orange peel tincture, 

carcinogenicity studies were available in the rat and mouse for d-limonene. An increased 

incidence of tumor formation was not observed in a 2 year carcinogenicity study on female rats 

or in male and female mice treated with d-limonene up to 1,000 mg/kg/day. An increased 

13 
incidence of tubular cell hyperplasia, adenomas, and adenocarcinomas of the kidney was 

observed in the male rat. However, these lesions are related to the accumulation of the alpha 2uglobulin protein which is specific to the male rat and is not relevant for human risk assessment. 

EPA has determined that reliable data show the safety of infants and children would be 

adequately protected ifthe FQPA SF were reduced to IX. 

Available toxicity data on sweet orange peel oil demonstrated effects at 1,500 mg/kg/day and 

no toxicity at doses up to 600 mglkg/day. Therefore, since there are no endpoints of concern for 

sweet orange peel tincture a qualitative dietary exposure risk assessment is appropriate. 

Sweet orange peel tincture is used as an inert ingredient in pesticide products that could 

result in residential exposure. However, based on the lack of toxicity, a quantitative exposure 

assessment from "residential exposures" was not performed. 

The Agency believes that amending the tolerance exemption to· include 40 CFR § 180.910 

will not significantly/measurably increase occupational exposure. The change in use pattern 

would be expanded to include use as a surfactant, fragrance and adjuvant inert ingredient up to 

10% concentration in pesticide products on all pre- and post-harvest food commodities. Based 

on the absence of toxicity of sweet orange peel tincture, it is not necessary to quantitatively 

assess occupational exposure. 

Ecotoxicity and fate and effects data were not available for sweet orange peel tincture. 

However, limited data is available for d-limonene. The acute toxicity of d-limonene ranges from 

slight to high for aquatic organisms. It caused moderate acute toxicity in insects and mites. It 

was biodegradable. 

Potential areas of environmental justice concerns, to the extent possible, were considered in 

this human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal 

Actions to Address Environmental Justice in Minority Populations and Low-Income 

Populations," http://www.eh.doe.gov/oepa/guidance/justice/eol2898.pdf. 

Taking into consideration all available information on sweet orange peel tincture (CAS Reg. 

No. 8028-48-6), EPA concludes that there is a reasonable certainty that no harm will result to the 

general population or to infants and children from aggregate exposure to sweet orange peel 

tincture. Therefore, the establishment of an exemption from tolerance under 40 CFR 180.910 for 

residues of sweet orange peel tincture for use as a surfactant, fragrance and adjuvant inert 

ingredient up to 10% concentration when used as an inert ingredient in pesticide formulations in 

pre- and post-harvest food commodities in the end-product formulation can be considered safe 

under section 408 of the FFDCA. 

14 
REFERENCES 

International Programme On Chemical Safety. Concise International Chemical Assessment 

Document No.5 Limonene. 1998. 

USEPA (1994) Reregistration Eligibility Decision (RED): Limonene. 

USEPA (2003) d-Limonene. Exposure and Risk Assessment on Lower Risk Pesticide 

Chemicals. d-Limonene. 

USEPA (2009) Screening-Level Hazard Characterization; Monoterpene Hydrocarbons 

Category. 

USEPA (2010) d-Limonene. Human-Health Assessment Scoping Document in Support of 

Registration Review. DP Barcode D374492. 

USEPA EPA 738-R-94-034. 1994 Reregistration Eligibility Decision (RED): Limonene. 

Vora, J.D., Matthews, R.F., Crandall, P.G., Cook, R. (1983). Preparation and Chemical 

Composition of Orange Oil Concentrates. Journal of Food Science, (48): 14-16. 

Friedrich K, Delgado IF, Santos LM, Paumgartten F J. Assessment of sensitization potential of 

monoterpenes using the rat popliteal lymph node assay. Food Chern Toxicol. 2007 Aug;45 

(8):1516-22. Epub 2007 Feb 17. 

Hoberman, A. (1992) Developmental Toxicity (Embryo-Fetal Toxicity and Teratogenic 

Potential) Study ofD-Limonene Technical Administrered Orally Via Gavage to Crl:CD®BR 

VAF/Plus® Presumed Pregnant Rats. Argus Research Laboratories, Inc., 905 Sheehy Drive 

Horsham, PA 19044. Laboratory Project ID 2119-001. MRID 42316301 

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