UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

MEMORANDUM 

March 30, 20 I 6 

SUBJECT: Cyprodinil. Human Health Risk Assessment for the Petition Proposing a New 

Tolerance for the Use of Cyprodinil inion Tree Nut Crop Group 14-12; except 

almond, except pistachio. 

PC Code: 288202 

Decision No.: 497939 

Petition No.: 4F8333 

Risk Assessment Type: NA 

TXR No.: NA 

MRID No.: 49346901, 49346902, 49346903, 

49346904, & 49346905 

FROM: 

DP Barcode: 0428823 

Registration Nos.: I 00-811 and 100-1317 

Regulatory Action: Section 3 

Case No.: 7025 

CAS No.: 12 1552-61-2 

40 CFR: 180.532 

THROUGH: Elissa Reaves, PhD, Branch Chief 

Risk Assessment Branch 4 

Health Effects Division (7509P) 

TO: Marcel Howard 

Fungicide Branch 

Registration Division (RD) (7505P) 

This document provides the Health Effects Division's (HED's) risk assessment of the proposed 

use of cyprodini I on Nut, tree, group 14- 12; except almond, except pistachio. 

Page I of 46 
1.0 EXECUTIVE SUMMARY ................................................................................................ 4 

2.0 HED RECOMMENDATIONS .......................................................................................... 7 

2.l Data Deficiencies/Conditions of Registration ................................................................ 7 

2.2 Tolerance Considerations ............................................................................................... 8 

2.2.1 Enforcement Analytical Method ............................................................................. 8 

2.2.2 International Harmonization ................................................................................... 8 

2.2.3 Recommended Tolerances ........................................................................................ 8 

2.2.4 Revisions to Petitioned-For Tolerances .................................................................. 8 

2.3 Label Recommendations ................................................................................................. 9 

3.0 INGREDIENT PROFILE .................................................................................................. 9 

3 .. 1 Chemical ldcnt·icy ............................................................................................................ 9 

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

3.3 Pesticide Use Pattern ....................................................................................................... 9 

3.4 Anticipated Exposure Path\vays ................................................................................... 10 

3.5 Considerations of Environmental Justice .................................................................... 10 

4.0 HAZARD CHARACTERIZATION/ASSESSMENT ................................................... 11 

4.l Toxicology Studies Available for Analysis .................................................................. 11 

4.2 Absorption, Distribution, Metabolism and Excretion ................................................ 11 

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

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

4.4.1 Completeness of the Toxicology Database ............................................................ 13 

4.4.2 Evidence of Neurotoxicity ...................................................................................... 14 

4.4.3 Evidence of Sensitivity/Susceptibility in the Developing or Young Animal ...... 14 

4.4.4 Residual Uncertainty in the Exposure Database .................................................. 14 

4.5 Toxicity Endpoint and Point of Departure .................................................................. 15 

4.5.1 Dose-Response Assessment .................................................................................... 15 

4.5.2 Recommendations for Combining Exposure Routes ........................................... 16 

4.5.3 Classification of Carcinogenic Potential ............................................................... 16 

4.5.4 Summary of Points of Departure Used in Risk Assessment ............................... 16 

5.0 DIETARY AND DRINKING WATER EXPOSURE AND RJSK ASSESSMENT .... 17 

5.l Metabolite/Degradate Residue Profile ......................................................................... 17 

5.1.1 Summary of Plant and Livestock Metabolism Studies ........................................ 17 

Page 2 of46 
Page 3 of 46

5.1.2 Comparison of Metabolic Pathways...................................................................... 18

5.1.3 Environmental Fate and Transport ...................................................................... 18

5.1.4 Residues of Concern Summary and Rationale..................................................... 19

5.2 Food Residue Profile ..................................................................................................... 19

5.2.1 Residues in Crops.................................................................................................... 19

5.3 Water Residue Profile ................................................................................................... 19

5.3.1 Estimated Drinking Water Concentrations.......................................................... 19

5.4 Dietary and Drinking Water Exposure and Risk....................................................... 20

5.4.1 Percent Crop Treated Used in Dietary Assessment............................................. 20

5.4.2 Acute Dietary and Drinking Water Analysis ....................................................... 21

5.4.3 Chronic Dietary and Drinking Water Analysis ................................................... 21

6.0 RESIDENTIAL EXPOSURE AND RISK ASSESSMENT .......................................... 22

6.1 Residential Bystander Postapplication Inhalation Exposure .................................... 22

6.2 Spray Drift...................................................................................................................... 23

7.0 AGGREGATE EXPOSURE AND RISK ASSESSMENT............................................ 23

7.1 Acute & Chronic Aggregate Risk................................................................................. 23

7.2 Short-Term Aggregate Risk ......................................................................................... 24

7.3 Intermediate-Term Aggregate Risk............................................................................. 24

8.0 CUMULATIVE RISK...................................................................................................... 24

9.0 OCCUPATIONAL EXPOSURE/RISK CHARACTERIZATION.............................. 25

9.1 Exposure Scenarios....................................................................................................... 25

9.2 Post Application Exposure............................................................................................ 25

9.2.1 Post Application Exposure Scenarios ................................................................... 25

9.2.4 Restricted Entry Interval ....................................................................................... 25

10. REFERENCES.................................................................................................................. 26

APPENDICES............................................................................................................................. 27

APPENDIX A: TOXICOLOGY DATA SUMMARY ......................................................... 27

APPENDIX B. Chemical Names And Structures Of Metabolites......................................... 44

APPENDIX C. Physical/Chemical Properties.......................................................................... 46

APPENDIX D. Studies Reviewed for Ethical Conduct.......................................................... 46
Page 4 of 46

1.0 EXECUTIVE SUMMARY

This assessment provides information to support a Section 3 registration for the use of cyprodinil 

on nut, tree, group 14-12; except almond, except pistachio. This document addresses the dietary, 

drinking water, residential and occupational exposures and risks associated with currently 

registered uses and the proposed new use of cyprodinil. It provides a reassessment of tolerances 

(pesticide residue limits in food) to ensure that they meet the safety standard established by the 

Food Quality Protection Act (FQPA) of 1996. 

Use Profile

Cyprodinil (4-cyclopropyl-6-methyl-N-phenyl-2-pyrimidinamine) is a systemic anilinopyrimidine fungicide. Permanent tolerances are established at 40 CFR §180.532 for residues of 

cyprodinil per se in/on a variety of crop commodities, at levels ranging from 0.02 ppm in/on 

almonds to 340 ppm in citrus oil. Cyprodinil is a systemic fungicide and is active through 

inhibition of methionine biosynthesis. Cyprodinil is applied to food crops with aircraft and 

ground application equipment. Cyprodinil is used on ornamental landscapes on golf courses and 

around residential, institutional, public, commercial and industrial buildings, parks, recreational 

areas and athletic fields. It is applied to non-food areas with ground-boom and handheld spray 

equipment. Since the label does not limit use to “professional” or certified applicators, there is 

potential for residential “handlers” to obtain and to apply the product. Residential exposures are 

limited to residential applicators; however, since cyprodinil is only used on ornamentals and 

there is no dermal POD, only inhalation exposure was assessed.

Proposed New Use

Under PP#4F8333, Syngenta is requesting the establishment of tolerances for residues of 

cyprodinil [4-cyclopropyl-6-methyl-N-phenyl-2-pyrimidinamin] in/on the following raw 

agricultural commodities:

Nut, Tree, Group 14-12; except almond, except pistachio.......0.04 ppm

In conjunction with PP# 4F8333, Syngenta is requesting a Section 3 registration for Inspire 

Super TM Fungicide (EPA Reg. No. 100-1317), a 2.09 lb ai/gallon emulsion oil in water (EW) 

formulation to tree nuts. In support of this new use, Syngenta has submitted new magnitude of 

the residue data on pecan and almond for cyprodinil.

Hazard Identification

The toxicology database for cyprodinil is adequate for evaluating and characterizing toxicity and 

selecting endpoints for purposes of this risk assessment. 
Page 5 of 46

The major target organs of cyprodinil are the liver in both rats and mice and the kidney in rats. 

Liver effects observed consistently in subchronic and chronic studies in rats and mice include 

increased liver weights, increases in serum clinical chemistry parameters associated with adverse 

effects on liver function, hepatocyte hypertrophy, and hepatocellular necrosis. Adverse kidney 

effects include tubular lesions and inflammation following subchronic exposure of male rats. 

The hematopoietic system also appeared to be a target of cyprodinil, causing mild anemia in rats 

exposed subchronically. Chronic effects in dogs were limited to decreased body-weight gain, 

decreased food consumption and decreased food efficiency. There was no evidence of increased 

susceptibility in the developmental rat or rabbit study following in utero exposure or in the twogeneration reproduction study following pre- or post-natal exposure. There was no evidence of 

neuropathological or other neurological effects in the available acute or subchronic neurotoxicity 

study. The submitted 28-day immunotoxicity study concluded no apparent suppression of the 

humoral component of the immune system. No dermal or systemic toxicity was seen following 

repeated dermal application at the highest dose in a 21 day dermal toxicity study in rabbits. 

There was no evidence of carcinogenic potential in either the rat chronic toxicity/carcinogenicity 

or mouse carcinogenicity studies. 

Cyprodinil has low acute toxicity via the oral, dermal, and inhalation routes (Toxicity Category 

III). Cyprodinil is mildly irritating to the eyes (Toxicity Category III) and negligibly irritating to 

the skin (Toxicity Category IV). It is a dermal sensitizer. 

Dose Response Assessment

Toxicological points of departure (PODs) were selected for dietary, occupational, and residential 

exposure scenarios. A POD (NOAEL = 200 mg/kg/day) for acute dietary exposure was selected 

for the general population and all population subgroups from an acute neurotoxicity study in rats 

based on clinical signs (hunched posture, piloerection, and reduced responsiveness to sensory 

stimuli, reduced motor activity and hypothermia). The POD (NOAEL = 2.7 mg/kg/day) for 

chronic dietary exposure was selected from a chronic/carcinogenicity feeding study in rats based 

on degenerative liver lesions (spongiosis hepatis) in males. A dermal exposure endpoint was not 

selected as no systemic toxicity was seen at the highest dose test in a 21 day dermal toxicity 

study in rabbits. A short-and intermediate term inhalation exposure POD of 62 mg/kg/day (No 

Observable Adverse Effect Level; NOAEL) was selected from a 28-day feeding study in rats 

based on decreased body-weight gain, increased cholesterol and phospholipid levels, 

microcytosis, and hepatocyte hypertrophy seen at the Lowest Observed Adverse Effect Level 

(LOAEL) of 299 mg/kg/day. An uncertainty factor of 100x was applied to PODs for both acute 

and chronic dietary exposure (10x for interspecies extrapolation, 10x for intraspecies variation). 

A recent HASPOC decision (TXR 0054812), based on a weight of evidence approach is 

requiring a 90-day inhalation toxicity study to reduce uncertainty associated with the use of an 

oral POD for assessing risk via the inhalation route. Therefore, in the absence of a route-specific 

inhalation study, a 10X database uncertainty factor for occupational workers and a 10x FQPA SF 

factor for residential scenarios should be applied specifically to the inhalation assessment. 
Page 6 of 46

Exposure/Risk Assessment and Risk Characterization

Risk assessments were conducted for dietary (food and water) and occupational exposure based 

on registered uses and requests for new use of cyprodinil on Nut, tree, group 14-12; except 

almond, except pistachio. The proposed use will not result in residential exposure; however, 

there is a currently registered ornamental use that has been previously evaluated to reflect 

updates to HED’s 2012 Residential Standard Operating Procedures (SOPs) (D398361, I. Nieves, 

5/3/12). No residential risks of concern were identified in the 2012 residential exposure 

assessment. Conservative acute and moderately refined chronic dietary and drinking water risk 

assessments for cyprodinil conclude that dietary and drinking water exposure estimates are 

below HED’s level of concern for the general population and all population subgroups. Dermal 

risks to agricultural workers following treatments were not assessed since no short- or 

intermediate-term dermal endpoint of concern was identified. The proposed use have been 

previously assessed in association with evaluation for similar use patterns (D398361, I. Nieves, 

5/3/12), and no risk estimates of concern were identified. 

Use of Human Studies

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

intentionally exposed to a pesticide or other chemical. These studies, listed in Appendix D have 

been determined to require a review of their ethical conduct. Some of these studies are also 

subject to review by the Human Studies Review Board. All of the studies used have received the 

appropriate review.

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.epa.gov/compliance/environmentaljustice/resources/policy/exec_order_12898.pdf).

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

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

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

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

pesticide use in a residential setting. Whenever appropriate, non-dietary exposures based on 

home use of pesticide products and associated risks for adult applicators and for toddlers, youths, 

and adults entering or playing on treated areas 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. 
Page 7 of 46

Tolerance Recommendation

There are no residue chemistry issues that would preclude granting the proposed use or 

establishment of the following tolerance for residues of cyprodinil. A revised Section F is 

required for the Syngenta Petition PP#4F8333 for the correct commodity definition. 

Nut, tree, group 14-12, except almond and pistachio ..... ...........0.04 ppm

Table 1. Tolerance Summary for Cyprodinil

Commodity Established/Proposed 

Tolerance (ppm)

Recommended 

Tolerance (ppm)

Comments; Correct Commodity 

Definition

Tolerances Proposed Under PP#4F8333

Nut, tree, group 14-12; 

except almond, except 

pistachio

0.04 0.04 Nut, tree, group 14-12, except almond 

and pistachio

No Codex, Canadian, or Mexican MRLs are established in/on tree nut commodities other than 

pistachio and almond.

2.0 HED RECOMMENDATIONS

2.1 Data Deficiencies/Conditions of Registration 

There are no deficiencies in the residue chemistry or exposure data requirements for the 

proposed actions. A revised Section F is required for the Syngenta Petition PP#4F8333. The 

HASPOC concluded (TXR 0054812), based on a weight of evidence (WOE) approach, that a 90-

day inhalation toxicity study is required at this time to reduce uncertainty associated with the use 

of an oral POD for assessing risk via the inhalation route. This determination considered all of 

the available hazard and exposure information for cyprodinil, including: (1) the use of an oral 

POD results in MOEs as low as 150 for risk via the inhalation route for intermediate-term 

exposure from occupational uses; and (2) the toxicological profile of cyprodinil indicates that 

toxicity increases with increased exposure from short-term to intermediate durations. Therefore, 

in the absence of a route-specific inhalation study, a 10X database uncertainty factor for 

occupational workers and a 10x FQPA SF factor for residential scenarios should be applied 

specifically to the inhalation assessment. 

Note to PM:

Tolerance should be revised, as needed, to reflect the correct commodity definitions as 

specified in Table 2.2.3.
Page 8 of 46

2.2 Tolerance Considerations

2.2.1 Enforcement Analytical Method

Adequate HPLC/UV methods (AG-631 and AG-631B) are available for enforcing tolerances of 

cyprodinil on plant commodities. The limits of quantitation (LOQ) for the plant methods range 

from 0.005 to 0.065 ppm depending on the commodity. An adequate LC/MS method 

(GRM010.01A) is also available for enforcing tolerances of cyprodinil residues in livestock 

commodities. The method LOQ for this method is 0.02 ppm for the combined residues of 

cyprodinil and its metabolite CGA-304075 (free and conjugated), expressed as parent.

2.2.2 International Harmonization

No Codex, Canadian, or Mexican MRLs are established in/on tree nut commodities other than 

pistachio and almond. 

2.2.3 Recommended Tolerances

HED has examined the residue chemistry database for cyprodinil and recommends in favor of 

the establishment of a tolerance for residues of cyprodinil in/on the following:

Nut, tree, group 14-12, except almond and pistachio...............0.04 ppm

Table 2.2.3. Tolerance Summary for Cyprodinil

Commodity Established/Proposed 

Tolerance (ppm)

Recommended 

Tolerance (ppm)

Comments; Correct Commodity 

Definition

40 CFR §180.532

Nut, tree, group 14-12; 

except almond, except 

pistachio

0.40 0.40 Nut, tree, group 14-12, except almond 

and pistachio

Adequate crop field trial data reflecting the proposed use patterns were submitted in support of 

the proposed use and tolerance. The Organization for Economic Cooperation and Development 

tolerance calculation procedures were utilized in determining the appropriate tolerance level for 

the proposed use. Tolerance should be revised, as needed, to reflect the correct commodity 

definitions as specified in Table 2.2.3. The proposed and recommended tolerance for residues of 

cyprodinil as a result of the subject action are presented in Table 2.2.3.

2.2.4 Revisions to Petitioned-For Tolerances

No changes to the petitioned-for tolerance are required. 
Page 9 of 46

2.3 Label Recommendations

The proposed use directions are adequate. 

3.0 INGREDIENT PROFILE 

3.1 Chemical Identity

Structure and nomenclature are reported in Table 3.1.

Table 3.1. Cyprodinil Nomenclature.

Chemical structure

Common name Cyprodinil

Company experimental name CGA219417

IUPAC name (4-cyclopropyl-6-methyl -pyrimidin-2-yl)-phenyl-amine

CAS name 2-pyrimidinamine, 4-cyclopropyl-6-methyl-N-phenylCAS registry number 121552-61-2

Molecular weight 225.29

End-use products (EP) 75% water-dispersible granule (WDG) formulation (VangardTM Fungicide; EPA Reg. No. 

100-828); a multiple active ingredient (MAI) end-use product (Inspire Super TM Fungicide; 

EPA Reg. No. 100-1317) formulated as an emulsion [oil] in water (EW), containing 8.4% 

difenoconazole and 24.1% cyprodinil

3.2 Physical/Chemical Characteristics 

The physicochemical properties of cyprodinil are reported in Appendix C. 

3.3 Pesticide Use Pattern

Proposed cyprodinil use patterns taken from submitted supplemental labels (Table 3.3). 

N

N

CH3

N

H
Page 10 of 46

Table 3.3. Summary of Proposed Directions for Use of Cyprodinil

Applic. Timing, 

Type, and 

Equip.

Formulation

[EPA Reg. 

No.]

Applic. 

Rate 

(lb ai/A)

Max. No. 

Applic. 

per Season

Max. Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and 

Limitations

Tree Nuts

Broadcast foliar

Ground & 

Aerial

Inspire Super

2.09 lb/gal 

EW

[100-1317]

0.33 4 implied 1.3 14

A minimum retreatment 

interval (RTI) of 14-21 

days is proposed. Do not 

apply more than 2 

applications by air.

3.4 Anticipated Exposure Pathways

The Registration Division has requested an assessment of human health risk to support the 

proposed new use of cyprodinil on Nut, tree, group 14-12; except almond, except pistachio. For 

domestic uses, humans may be exposed to cyprodinil in food and drinking water, since 

cyprodinil may be applied directly to growing crops and application may result in cyprodinil

reaching surface and ground water sources of drinking water. There are also residential uses of 

cyprodinil on ornamentals, so there is exposure in residential or non-occupational settings. In an 

occupational setting, applicators may be exposed while handling the pesticide prior to 

application, as well as during application. There is a potential for post-application exposure for 

workers re-entering treated fields. 

Risk assessments have been previously prepared for the existing uses of cyprodinil. This risk 

assessment considers all of the aforementioned exposure pathways based on the proposed use of 

cyprodinil, but also considers the existing uses as well, particularly for the dietary exposure 

assessment.

3.5 Considerations of Environmental Justice

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

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

to Address Environmental Justice in Minority Populations and Low-Income Populations," 

(http://www.epa.gov/compliance/environmentaljustice/resources/policy/exec_order_12898.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 U.S. Department of Agriculture’s (USDA’s) National Health and Nutrition Examination

Survey/What We Eat in America, (NHANES/WWEIA), are used in pesticide risk assessments 

for all registered food uses of a pesticide. These data are analyzed and categorized by subgroups 
Page 11 of 46

based on age, season of the 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.

4.0 HAZARD CHARACTERIZATION/ASSESSMENT

4.1 Toxicology Studies Available for Analysis

The toxicology database for cyprodinil is adequate for evaluating and characterizing cyprodinil 

toxicity and selecting endpoints for purposes of this risk assessment. Acute neurotoxicity 

(MRID 48304202) and immunotoxicity studies (MRIDs 48304203, 4829350) required under 

revised 40 CFR Part 158 Toxicology Data Requirements have been submitted and determined to 

be acceptable. Based on a weight of evidence (WOE) approach a 90-day inhalation toxicity 

study is required at this time to reduce uncertainty associated with the use of an oral POD for 

assessing risk via the inhalation route (HASPOC, TXR 0054812). 

4.2 Absorption, Distribution, Metabolism and Excretion

Absorption, distribution, metabolism, and excretion of cyprodinil were studied in rats. In an 

initial study, single oral doses (0.5 or 100 mg/kg bw) of phenyl or pyrimidyl-radiolabeled 

cyprodinil were administered with one low-dose group receiving unlabeled cyprodinil for two 

weeks prior to treatment with radiolabeled compound. Absorption was very rapid (peak 

concentration at 0.3 hours) with rapid clearance (half-life of < 2 hrs). A minimum of 75% of the 

administered dose was absorbed. Excretion was rapid and almost complete, with urine as the 

principle route of excretion (48-68%), and >90% of the administered dose detected in the urine 

and feces within 48 hours. Tissue residues declined rapidly, with the highest concentrations (<

1.8 ppm) found in kidneys, liver, lungs, spleen, thyroid, whole blood, and carcass. The urine, 

fecal, and bile metabolite patterns were complex, with eight, eight, and nine defined metabolite 

fractions, respectively. Unchanged parent compound was detected in feces extract only. 

Excretion, distribution and metabolite profiles were independent of dose level, pretreatment, and 

type of label, although there were some quantitative differences sex-dependent qualitative 

differences in two urinary metabolite fractions.

In a follow-up study, excreta and bile from radiolabeled rats from the previous study were used 

to characterize, isolate and identify the metabolites detected in that study. Eleven metabolites 

were isolated from urine, feces and bile, and the metabolic pathways in the rat were proposed. 
Page 12 of 46

All urinary and biliary metabolites but one were conjugated with glucuronic acid or sulfonated, 

and excreted. Cyprodinil was almost completely metabolized by hydroxylation of the phenyl 

ring or pyrimidine ring, followed by conjugation. An alternative pathway involved oxidation of 

the phenyl ring followed by glucuronic acid conjugation. The major metabolic pathways of 

cyprodinil were not significantly influenced by the dose, treatment regimen, or sex of the animal.

4.3 Toxicological Effects

The major target organs of cyprodinil are the liver and the kidney. Liver effects were consistent 

among male and female rats and mice in both subchronic and chronic studies and typically 

included increased liver weights along with increases in serum clinical chemistry parameters 

associated with adverse effects on liver function (i.e., increased cholesterol and phospholipid 

levels). Microscopic lesions in rats and mice included hepatocyte hypertrophy and 

hepatocellular necrosis. In the kidneys, adverse effects were seen as chronic tubular lesions and 

chronic kidney inflammation following subchronic exposure of male rats. Chronically, 

cyprodinil caused increased kidney weights and progressive nephropathy in male rats. Chronic 

effects in dogs were limited to decreased body-weight gain, decreased food consumption and 

decreased food efficiency; liver toxicity was not seen in the dog. The hematopoietic system also 

appeared to be a target of cyprodinil as mild anemia was seen in rats exposed subchronically 

(reductions in hematocrit and hemoglobin and microcytosis). Although increases in thyroid 

weight and/or hypertrophy of thyroid follicular cells were observed at higher doses in the rat 28-

day oral-toxicity studies (both feeding and oral gavage) and in the 90-day oral-toxicity study in 

rats, treatment related changes in thyroid weights or gross/microscopic observations were not 

observed in the chronic rat study or in other studies (thyroid hormones were not evaluated in any 

study). A 28-day dietary immunotoxicity study in mice resulted in no apparent suppression of 

the humoral component of the immune system. The only effect attributed to cyprodinil treatment 

was higher mean absolute, relative (to body weight), and adjusted liver weights for the 5000 ppm 

group. There were no treatment-related effects on absolute, adjusted, or relative spleen or 

thymus weights; no effects on specific activity or total activity of splenic IgM antibody-forming 

cells to the T cell-dependent antigens RBC. No dermal or systemic toxicity was seen following 

repeated dermal application at the highest dose in a 21 day dermal toxicity study in rabbits.

An acute neurotoxicity study indicated systemic toxicity with signs of induced hunched posture, 

piloerection, and reduced responsiveness to sensory stimuli and reduced motor activity. Females 

were slightly more affected than males per daily clinical observations, which disappeared by day 

three to four. A dose-related reduction in body temperature was seen in all treated animals, thus 

hypothermia is considered a compound-related effect in the HDT and was found to be 

statistically significant, whereas the lower dosed animals was not or only marginally significant 

and was fully reversible in all groups. Clinical signs, hypothermia, and changes in motor activity 

were found to all be reversible by day eight and 15 investigations. There were no 

histopathological findings to support evidence of damage to the central nervous system, eyes, 

optic nerves, or skeletal muscles. A subchronic neurotoxicity study showed no treatment related 

effects on mortality, clinical signs, or gross or histological neuropathology. FOB and motor 
Page 13 of 46

activity testing revealed no treatment related effects up to the highest dose tested. No clinical 

signs suggestive of neurobehavioral alterations or evidence of neuropathological effects were 

observed in the available oral-toxicity studies. There was also no evidence of a 

neurodevelopmental effect in the rat or rabbit developmental-toxicity studies or in the rat two 

generation reproductive-toxicity study. 

There was no evidence of increased susceptibility in the developmental rat or rabbit study 

following in utero exposure or in the two-generation reproduction study following pre- and postnatal exposure. Fetal toxicity, manifested as significantly lower fetal weights and an increased 

incidence of delayed ossification in the rat and a slight increase in litters showing extra ribs (13th) 

in the rabbit, was reported in developmental toxicity studies. In a rat two generation 

reproduction study, significantly lower pup weights for F1 and F2 offspring were observed. 

However, each of these fetal/neonatal effects occurred at the same dose levels at which maternal 

toxicity (decreased body weight gain) was observed and were considered to be secondary to 

maternal toxicity. 

Cyprodinil has low acute toxicity via the oral, dermal, and inhalation routes (Toxicity Category 

III). Cyprodinil is mildly irritating to the eyes (Toxicity Category III) and negligibly irritating to 

the skin (Toxicity Category IV). It is a dermal sensitizer. 

The complete toxicity profile for cyprodinil is provided in Appendix A. 

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

For non-inhalation routes of exposure, the FQPA factor for potential susceptibility to infants and 

children is reduced to 1X based on the following considerations. 

- The toxicology data base for cyprodinil is complete and adequate for assessing 

susceptibility under FQPA.

- There is no indication of susceptibility of rats or rabbit fetuses to in utero and/or postnatal 

exposure in the developmental and reproductive toxicity data.

- There are no residual uncertainties in the exposure database.

- The dietary and residential exposure and risk assessments are conservative and will not 

underestimate exposure to cyprodinil.

For inhalation exposure scenarios for all population groups, EPA is retaining a 10X FQPA safety 

factor for the lack of a route specific inhalation study.

4.4.1 Completeness of the Toxicology Database

The toxicity database for cyprodinil is sufficient for a full hazard evaluation and is considered 

adequate to evaluate risks to infants and children. Acceptable studies have been submitted for 

developmental toxicity, reproductive toxicity, acute and subchronic neurotoxicity and 

immunotoxicity. Based on a weight of evidence (WOE) approach a 90-day inhalation toxicity 
Page 14 of 46

study is required at this time to reduce uncertainty associated with the use of an oral POD for 

assessing risk via the inhalation route (HASPOC, TXR 0054812). However, in the absence of a 

route-specific inhalation study, a 10X database uncertainty factor for occupational workers and a 

10X FQPA SF factor for residential scenarios should be applied specifically to the inhalation 

assessment. 

4.4.2 Evidence of Neurotoxicity

In a subchronic neurotoxicity study in rats, there were no treatment related effects on mortality, 

clinical signs, or gross or histological neuropathology. Functional Observational Battery (FOB) 

and motor activity testing revealed no treatment related effects up to the highest dose tested. In 

an acute neurotoxicity study in mice, clinical signs, hypothermia, and changes in motor activity 

were all found to be reversible and no longer seen at day 8 and 15 investigations. There were no 

treatment related effects on mortality, gross or histological neuropathology. Reduced motor 

activity, induced hunched posture, piloerection and reduced responsiveness to sensory stimuli 

were observed and disappeared in all animals by day 3 to 4.

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

The available acceptable guideline studies indicated no increased susceptibility of rats or rabbits 

to in utero and/or from postnatal exposure to cyprodinil. In the prenatal developmental toxicity 

studies in rats and rabbits and the two-generation reproduction study in rats, toxicity to the 

fetuses/offspring, when observed, occurred at the same doses at which effects were observed in 

maternal/parental animals. 

In a rat developmental toxicity study, there were significantly lower mean fetal weights in the 

high-dose group compared to controls as well as a significant increase in skeletal anomalies in 

the high-dose group due to abnormal ossification. The skeletal anomalies/variations were 

considered to be a transient developmental delay that occurs secondary to the maternal toxicity 

noted in the high-dose group. In the rabbit study, the only treatment related developmental effect 

was indication of an increased incidence of a 13th rib at maternally toxic doses. Signs of fetal 

effects in the reproductive toxicity study included significantly lower F1 and F2 pup weights in 

the high-dose group during lactation, which continued to be lower than controls post-weaning 

and after the pre-mating period (examination in F1 generation only). Reproductive effects were 

seen only at doses that also caused parental toxicity.

4.4.4 Residual Uncertainty in the Exposure Database 

There are no residual uncertainties in the exposure database. The residue data base is adequate. 

The dietary risk assessment is conservative and will not underestimate dietary exposure to 

cyprodinil. The residential exposure estimates included in the aggregate risk assessment are 

conservative based on maximum use rates and will not underestimate non-dietary risks to 

homeowners. 
Page 15 of 46

4.5 Toxicity Endpoint and Point of Departure

4.5.1 Dose-Response Assessment

An acute POD of 200 mg/kg was selected from an acute neurotoxicity study in rats based on 

LOAEL of 600 mg/kg showing clinical signs (hunched posture, piloerection, and reduced 

responsiveness to sensory stimuli, reduced motor activity and hypothermia). An uncertainty 

factor (UF) of 100x (10x to account for interspecies extrapolation and 10x for intraspecies 

variation) was applied to the NOAEL to obtain an acute reference dose (aRfD) of 2.0 mg/kg/day. 

Since the FQPA factor has been reduced to 1X, the acute population adjusted dose (aPAD) is 

equivalent to the aRfD. The selected endpoint is considered appropriate for acute dietary 

exposure because effects were seen after a single dose. 

A chronic POD of 2.7 mg/kg/day (NOAEL) was selected from a chronic/carcinogenicity oral 

study in rats based on the histopathological alterations in the liver (spongiosis hepatis) in males 

at 35.6 mg/kg/day (LOAEL). The selected NOAEL is the lowest NOAEL observed in the most 

sensitive species following long-term exposure. A UF 100x (10x to account for interspecies 

extrapolation and 10x for intraspecies variation) was applied to the dose to obtain a chronic 

reference dose (cRfD/cPAD) of 0.027 mg/kg/day. 

The NOAEL (62 mg/kg/day) from a 28-day feeding study in rats based on decreased bodyweight gain, increased cholesterol and phospholipid levels, microcytosis, and hepatocyte 

hypertrophy was selected as the POD for a short-term incidental oral exposure. The short-term 

incidental oral endpoint was selected for the residential aggregate assessment as a result of spray 

drift. The POD is considered conservative since it is lower than the NOAEL established for 

offspring in the reproduction and fertility effects study (MRID 43709034). The level of concern 

(LOC) for the short term incidental oral exposure is 100 based on uncertainty factors of 

interspecies variability (UFA=10X) and intraspecies sensitivity (UFH=10X). 

A POD for dermal exposure was not selected because no dermal or systemic toxicity was seen 

following repeated dermal application at the highest dose tested in a 21 day dermal toxicity study 

in rabbits. 

A short-and intermediate term inhalation exposure POD of 62 mg/kg/day (No Observable 

Adverse Effect Level; NOAEL) was selected from a 28-day feeding study in rats based on 

decreased body-weight gain, increased cholesterol and phospholipid levels, microcytosis, and 

hepatocyte hypertrophy seen at the Lowest Observed Adverse Effect Level (LOAEL) of 299 

mg/kg/day. This POD of 62 mg/kg/day is appropriate and protective for the longer-term 

intermediate exposure scenario since there is no progression of toxicity observed in the 90-day 

SCN study where the NOAEL is 54 mg/kg/day based on decreased body weight gain, hepatocyte 

hypertrophy, kidney tubular casts, thyroid follicular cell hypertrophy at the LOAEL of 600 

mg/kg/day. The toxicological profile of cyprodinil indicates that toxicity increases with 

increased durations, specifically between short-term (28-day) and long-term exposures (2-year). 
Page 16 of 46

Therefore, based on the weight of evidence regarding cyprodinil, a 90-day inhalation toxicity 

study is required to reduce uncertainties associated with the use of an oral POD for assessing risk 

via the inhalation route. 

4.5.2 Recommendations for Combining Exposure Routes

When there are potential residential exposures to the pesticide, aggregate risk assessment must 

consider exposures from three major sources: oral, dermal and inhalation exposures. An 

aggregate risk assessment of combined short-term inhalation and background dietary exposure is 

required for residential handlers because PODs selected for these exposure routes are based on 

common toxicological effects (i.e., liver effects).

4.5.3 Classification of Carcinogenic Potential

Based on the lack of evidence of carcinogenicity in mice and rats at doses that were judged to be 

adequate to assess the carcinogenic potential, cyprodinil was classified by the HED Hazard 

Identification Assessment Review Committee (HIARC) (TXR number 0051401) as “not likely to 

be carcinogenic to humans.”

4.5.4 Summary of Points of Departure Used in Risk Assessment

Toxicological doses/endpoints selected for the cyprodinil risk assessment are provided in Table 

4.5.4.1 and 4.5.4.2.

Table 4.5.4.1. Summary of Toxicological Doses and Endpoints for Cyprodinil for Use in Dietary Human Health Risk 

Assessments

Exposure/Scenario Point of 

Departure

Uncertainty/

FQPA Safety 

Factors

RfD, PAD, LOC 

for Risk 

Assessment

Study and Toxicological Effects

Acute Dietary

(All Populations)

NOAEL = 200

mg/kg

UFA= 10x

UFH=10x

FQPA SF= 1x

Acute RfD = 2.0

mg/kg 

aPAD = 2.0

mg/kg/day 

Acute Neurotoxicity - Rat

LOAEL = 600 mg/kg based on clinical signs 

of toxicity (hunched posture, piloerection, 

and reduced responsiveness to sensory 

stimuli, reduced motor activity and 

hypothermia)

Chronic Dietary 

(All Populations)

NOAEL= 2.7 

mg/kg/day

UFA= 10x

UFH=10x

FQPA SF= 1x

Chronic RfD = 

0.027

mg/kg/day

cPAD = 

0.027mg/kg/day

2-Year Chronic Toxicity/ Carcinogenicityrat

LOAEL = 35.6 mg/kg/day based on 

degenerative liver lesions (spongiosis 

hepatis) in males.

Cancer (all routes) Classification: “Not likely to be carcinogenic to humans” (TXR 0051401)

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to 

mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. 

NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. 

UF = uncertainty factor. UFA = extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity 

among members of the human population (intraspecies). SF = FQPA Safety Factor. PAD = population adjusted dose (a = acute, 

c = chronic). RfD = reference dose. 
Page 17 of 46

Table 4.5.4.2. Summary of Toxicological Doses and Endpoints for Cyprodinil for Use in Non-Dietary Human Health 

Risk Assessments

Exposure/Scenario Point of 

Departure

Uncertainty 

Factors

Level of Concern 

for Risk 

Assessment

Study and Toxicological Effects

Incidental Oral

Short-term (1-30 

Days)

Oral NOAEL= 62 

mg/kg/day

UFA= 10x

UFH=10x

FQPA SF=

1x

LOC = 100

28-Day Feeding/Range-Finding - Rat

LOAEL = 299 mg/kg/day based on 

decreased body-weight gain, increased 

cholesterol and phospholipid levels, 

microcytosis, and hepatocyte hypertrophy.

Dermal Short-Term 

(1-30 days) 

No dermal or systemic toxicity was seen following repeated dermal application at the highest dose tested 

for 21 days to rabbits. Therefore a POD for dermal exposure was not selected.

Inhalation Short-/ 

Intermediate Term 

(1-30 days) 

Oral NOAEL= 62 

mg/kg/day

(inhalation 

absorption rate = 

100%)

Residential: 

UFA = 10x

UFH = 10x

FQPA SF = 

10X*

Occupational: 

UFA = 10x

UFH = 10x

UFDB = 10X

Residential LOC 

for MOE = 1,000 

Occupational 

LOC for MOE = 

1,000

28-Day Feeding/Range-Finding - Rat

LOAEL = 299 mg/kg/day based on 

decreased body-weight gain, increased 

cholesterol and phospholipid levels, 

microcytosis, and hepatocyte hypertrophy.

The POD of 62 mg/kg/day is appropriate 

and protective for the longer-term 

intermediate exposure scenario since there is 

no progression of toxicity observed in the 

90-day SCN study where the NOAEL is 54 

mg/kg/day based on decreased body weight 

gain, hepatocyte hypertrophy, kidney tubular 

casts, thyroid follicular cell hypertrophy at 

the LOAEL of 600 mg/kg/day.

Cancer (all routes) Not likely human carcinogen

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to 

mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. 

NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. 

UF = uncertainty factor. UFA = extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity 

among members of the human population (intraspecies). UFDB = lack of inhalation study. SF = FQPA Safety Factor MOE = 

margin of exposure. LOC = level of concern. * FQPA SF is composed of the 10X factor for the inhalation study data gap. 

5.0 DIETARY AND DRINKING WATER EXPOSURE AND RISK ASSESSMENT

5.1 Metabolite/Degradate Residue Profile

5.1.1 Summary of Plant and Livestock Metabolism Studies

The nature of the residue in plants is adequately understood based on acceptable metabolism 

studies on apple, peach, potato, tomato, and wheat. The nature of the residue in ruminants is 

adequately understood based on acceptable lactating goat metabolism studies. A poultry 

metabolism study is not available but is not required for this action since there are no poultry 

feed stuffs associated with the proposed new use of cyprodinil on tree nut crop group 14-12 
Page 18 of 46

except almond and pistachio. The nature of the residue in confined rotational crops is 

understood.

5.1.2 Comparison of Metabolic Pathways

Based on acceptable metabolism studies on apple, peach, potato, tomato, and wheat, cyprodinil is 

metabolized primarily by hydroxylation followed by sugar conjugation. Cleavage of the amino 

bridge, opening of the pyrimidine ring, opening of the cyclopropyl ring and formation of 

thiolactic acid conjugates are minor pathways. The metabolism of cyprodinil in ruminant 

proceeds predominantly via hydroxylation followed by conjugation with sulfuric and glucuronic 

acid. Breakdown of the pyrimidinyl ring was seen only in the liver and resulted in Metabolite 

L1. Cleavage of the amino bridge between the phenyl and the pyrimidinyl rings was only a 

minor reaction as indicated by the small amounts of CGA 249287 found in the liver and kidneys 

of goats dosed with [14C-pyrimidinyl] cyprodinil. Free and conjugated CGA-304075 was a major 

residue in muscle, liver, kidney, and milk based on acceptable lactating goat metabolism studies 

using [14C-phenyl] and [14C-pyrimidinyl] cyprodinil. 

In metabolism studies in rats, cyprodinil was almost completely metabolized by hydroxylation of 

the phenyl ring or pyrimidine ring, followed by conjugation. An alternative pathway involved 

oxidation of the phenyl ring followed by glucuronic acid conjugation. In the rat study, eleven 

metabolites were isolated from urine, feces and bile, and the metabolic pathways in the rat were 

proposed. All urinary and biliary metabolites but one were conjugated with glucuronic acid or 

sulfonated, and excreted. CGA 304075 was not separately identified as an isolated metabolite in 

the rat study.

 

5.1.3 Environmental Fate and Transport

The environmental fate data base for cyprodinil is substantially complete. Cyprodinil has a 

relatively low solubility in water. Based on its octanol/water partition coefficient, it is likely to 

partition with organic tissues and other organic media. It is alkaline in water. It is not likely to 

volatilize substantially based on its low vapor pressure and Henry’s Law constant. Cyprodinil 

appears to bind strongly to particulate and sediment, showing relatively low soil mobility. It

appears to be a persistent compound under most conditions, except aerobic soil metabolism, as 

demonstrated in laboratory studies. Its potential for groundwater contamination appears to be 

low. However, due to its high persistence under aquatic conditions, aquifers that lie below areas 

that have low organic content and coarse textured soils or shallow leaky aquifers could be prone 

to contamination. Even though buffer zones can ameliorate moderately the level of spray drift, 

the potential for runoff still exists for long periods of time. Cyprodinil has a high affinity to sorb 

to soil and particulate suggests the potential for runoff in eroded particles. This stability and 

binding to particulate and organic matter (aerobic and anaerobic conditions) suggests that 

cyprodinil residues in sediments could contribute to a possible resuspension of the compound 

through mixing and mass balance for an extended period. Degradates of cyprodinil include 4-

cyclopropyl-6-methyl-2-amine-pyrimidine, CGA-275535 (slightly mobile), CGA-321915 
Page 19 of 46

(mobile to moderately mobile), and CGA-249287 (moderately mobile) (degradate identified of 

concern in this assessment; 11.7% at 28 days in the aerobic soil metabolism study, and 14.2% in 

the aerobic aquatic metabolism study). The water residues of concern are the parent and CGA 

249287 (4-cyclopropyl-6-methylpyrimidin-2-amine) (D292557, 6/8/03).

5.1.4 Residues of Concern Summary and Rationale

Residues of concern for dietary and drinking water risk assessment and tolerance expression for 

cyprodinil are provided in Table 5.1.4. HED has concluded that the residues of concern for 

livestock for both risk assessment and the tolerance definition should include the combined 

residues of cyprodinil and free and conjugated CGA-304075 (4-[(4-cyclopropyl-6-

methylpyrimidin-2-yl)amino]-phenol, expressed in parent equivalents (D345970 and D345182, 

G. Kramer, 6/4/08). The water residues of concern are the parent and CGA 249287 (4-

cyclopropyl-6-methylpyrimidin-2-amine) (D292557, 6/8/03).

Table 5.1.4. Summary of Metabolites and Degradates to be included in the Risk Assessment and 

Tolerance Expression for Cyprodinil

Matrix Risk Assessment Tolerance Expression

Plants cyprodinil cyprodinil

Livestock cyprodinil and CGA-304075 cyprodinil and CGA-304075

Water cyprodinil and CGA 249287 NA

5.2 Food Residue Profile

5.2.1 Residues in Crops

In tree nuts harvested at a PHI of 13-14 days following the last of four foliar broadcast 

applications of a 2.09 lb ai/gal EW formulation at a total rate of 1.30-1.34 lb ai/A, individual 

sample (and per-trial average) residues of cyprodinil were <0.010-0.0408 (<0.010-<0.0254) ppm 

in/on pecan (nutmeat), <0.010-0.0146 (<0.010-0.0131) ppm in/on almond (nutmeat), and 0.707-

6.46 (0.707-5.48) ppm in/on almond (hulls).

In the one residue decline trial, residues of cyprodinil generally declined in/on almond nutmeat 

and hulls with increasing PHI.

5.3 Water Residue Profile

5.3.1 Estimated Drinking Water Concentrations 

Drinking water residues were incorporated directly into the acute and chronic dietary analyses as 

“water, direct, all sources” and “water, indirect, all sources” and were provided by the 

Environmental Fate and Effects Division (EFED) (D425914, J Melendez 5/4/15). The tier 2 

aquatic models PRZM (Pesticide Root Zone Model)-EXAMS (Exposure Analysis Modeling 

System), and the models Screening Concentration in Ground Water (SCI-GROW) and Pesticide 
Page 20 of 46

Root Zone Model for Groundwater (PRZM-GW) were used to obtain estimated drinking water 

concentrations (EDWCs) in surface water and groundwater, respectively. The acute EDWC in 

surface water is 34.8 μg /L for the total residues of cyprodinil plus CGA-249287. The chronic 

EDWC in surface waters is 24.7 μg /L for the total residues of cyprodinil and CGA-249287. The 

cancer/chronic EDWC in surface waters is 16.4 μg /L for the total residues of cyprodinil and 

CGA-249287. All surface waters EDWCs were obtained using the New York grapes PRZM 

scenario. The PRZM-GW generated EDWC for the use on grapes, using the FL citrus surrogate 

scenario were 2.05 μg /L for the total residues of cyprodinil and CGA-249287 (acute) and 1.80 

μg /L for the total residues (chronic). For details on methods, characterization of results, 

uncertainties, etc., please, refer to the previous DWAs. Table 5.3.1 provides a summary of the 

Tier 2 modeled drinking water concentrations.

Table 5.3.1. Maximum Estimated Drinking Water Concentrations for the Use of Cyprodinil (expressed as total 

residues of cyprodinil plus its degradate CGA-249287)

DRINKING WATER SOURCE 

(MODEL USED) USE (rate modeled per year)

MAXIMUM ESTIMATED DRINKING WATER 

CONCENTRATION (EDWC) ( ppb)

Groundwater (PRZM-GW) FL citrus1(1.4 lb a.i.) Acute 2.05

Chronic 1.80

Surface water

(PRZM/EXAMS) NY grapes (1.4 lb a.i.)

Acute 34.8

Chronic 24.7

Cancer/Chronic 16.4

1 Scenario was used as a surrogate and run with the maximum application rate for grapes.

5.4 Dietary and Drinking Water Exposure and Risk

Screening level acute and refined chronic dietary and drinking water exposure and risk 

assessments were conducted using the Dietary Exposure Evaluation Model software with the 

Food Commodity Intake Database DEEM-FCIDTM, Version 3.16, which incorporates 

consumption data from USDA’s National Health and Nutrition Examination Survey, What We 

Eat in America, (NHANES/WWEIA). This dietary survey was conducted from 2003 to 2008. 

Dietary risk assessment incorporates both exposure and toxicity of a given pesticide. The acute 

dietary exposure assessment used tolerance level residues. For the chronic dietary analysis, 

average field trial residues for pome fruit, head lettuce, leaf lettuce, spinach, tomato, and grapes 

and tolerance level residues for the remaining commodities. For acute and chronic dietary 

assessments, the risk is expressed as a percentage of a maximum acceptable dose (i.e., the dose 

which HED has concluded will result in no unreasonable adverse health effects). This dose is 

referred to as the population adjusted dose (PAD). The PAD is equivalent to the reference dose 

(RfD) divided by the additional Safety Factor, if applied. For acute and non-cancer chronic 

exposures, HED is concerned when estimated dietary risk exceeds 100% of the PAD. 

5.4.1 Percent Crop Treated Used in Dietary Assessment

The acute and chronic dietary exposure analyses assumed 100% crop treated (CT). 
Page 21 of 46

5.4.2 Acute Dietary and Drinking Water Analysis

A new dietary assessment was conducted for the proposed new use. The proposed use results dietary 

risk estimates below HED’s level of concern; see Table 5.4.1.1. The highest is children 1-2 years 

resulting in 8.6% of the aPAD. 

Table 5.4.1.1. Summary of Acute Dietary (Food plus Water) Exposure and Risk for Cyprodinil at the 95th

Percentile.

Population Subgroup aPAD (mg/kg) Exposure (mg/kg) %aPAD

General U.S. Population

2.0

0.095199 4.8

All Infants (< 1 year old) 0.101590 5.1

Children 1-2 years old 0.172630 8.6

Children 3-5 years old 0.158663 7.9

Children 6-12 years old 0.083374 4.2

Youth 13-19 years old 0.071554 3.6

Adults 20-49 years old 0.091867 4.6

Adults 50-99 years old 0.091596 4.6

Females 13-49 years old 0.096707 4.8

The bolded %aPAD is the highest.

5.4.3 Chronic Dietary and Drinking Water Analysis

A new dietary assessment was conducted for the proposed new uses of cyprodinil and results in 

dietary risk estimates below HED’s level of concern; see Table 5.4.2.

Table 5.4.2. Summary of Chronic Dietary (Food plus Water) Exposure and Risk for cyprodinil.

Population Subgroup cPAD (mg/kg/day) Exposure (mg/kg/day) %cPAD

General U.S. Population

0.027

0.007795 29

All Infants (< 1 year old) 0.013044 48

Children 1-2 years old 0.023047 85

Children 3-5 years old 0.016594 62

Children 6-12 years old 0.008524 32

Youth 13-19 years old 0.004666 17

Adults 20-49 years old 0.006329 23

Adults 50-99 years old 0.007775 29

Females 13-49 years old 0.006708 25

The bolded %cPAD is the highest.
Page 22 of 46

6.0 RESIDENTIAL EXPOSURE AND RISK ASSESSMENT

The proposed use will not result in residential exposure; however, there is a currently registered 

ornamental use that has been previously evaluated to reflect updates to HED’s 2012 Residential 

Standard Operating Procedures (SOPs) (D398361, I. Nieves, 5/3/12). No risk estimates of 

concern were identified. For the ornamental use, residential handler and post-application 

exposures are expected; however, only residential handler inhalation risks have been assessed. 

Post-application dermal exposure was not quantified since no dermal endpoint was identified for 

cyprodiniland children’s incidental oral exposures are not an anticipated pathway of exposure for 

the ornamental use pattern. The updated residential handler (inhalation only) results for the 

residential use impacting the aggregate are presented below in table 6.0 for reference purposes. 

Table 6.0. Residential Handler Inhalation Exposure and Risk Estimates for Cyprodinil.

Application 

Site

Application 

Equipment

Max 

Application 

Ratea

Amount 

AI 

Handled b

Unit 

Exposuresc

(mg/lb ai)

Absorbed 

Daily Dosed

(mg/kg-day)

MOEe

LOC=1000

(lb ai/gallon 

solution)

(gallons 

solution)

Ornamentals

Manuallypressurized 

Handwand 0.00141

5 1.1 0.000098 640,000

Hose-end Sprayer 11 0.0014 0.00000027 230,000,000

Backpack 5 1.1 0.000098 640,000

a. Application Rate based on proposed use on label for PalladiumTM Fungicide (EPA Reg. No. 100-1328).

b. Based on 2012 Residential SOPs.

c. Unit Exposures based on 2012 Residential SOPs.

d. Inhalation Dose (mg/kg/day) = daily unit exposure (mg/lb ai) * application rate (lb ai/gallon) * amount handled (gallons) / body 

weight (80 kg); 

e. Inhalation MOE = PoD (NOAEL of 62 mg/kg/day) / Daily inhalation dose (mg/kg/day). Level of concern = 1000. 

6.1 Residential Bystander Postapplication Inhalation Exposure

Volatilization of pesticides may be a source of post-application inhalation exposure to 

individuals nearby pesticide applications. The agency sought expert advice and input on issues 

related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act 

Scientific Advisory Panel (SAP) in December 2009, and received the SAP’s final report on 

March 2, 2010 (http://www.epa.gov/scipoly/sap/meetings/2009/120109meeting.html). The 

agency has evaluated the SAP report and has developed a Volatilization Screening Tool and a 

subsequent Volatilization Screening Analysis 

(http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219).

During Registration Review, the agency will utilize this analysis to determine if data (i.e., flux 

studies, route-specific inhalation toxicological studies) or further analysis is required for 

cyprodinil.
Page 23 of 46

6.2 Spray Drift

Spray drift is a potential source of exposure to those nearby pesticide applications. This is 

particularly the case with aerial application, but, to a lesser extent, spray drift can also be a 

potential source of exposure from the ground application methods (e.g., groundboom and 

airblast) employed for cyprodinil. The agency has been working with the Spray Drift Task Force 

(a task force composed of various registrants which was developed as a result of a Data Call-In 

issued by EPA), EPA Regional Offices and State Lead Agencies for pesticide regulation and 

other parties to develop the best spray drift management practices (see the agency’s Spray Drift 

website for more information). The agency has also developed a policy on how to appropriately 

consider spray drift as a potential source of exposure in risk assessments for pesticides. The 

potential for spray drift will be quantitatively evaluated for each pesticide during the Registration 

Review process which ensures that all uses for that pesticide will be considered 

concurrently. The approach is outlined in the revised (2012) Standard Operating Procedures 

For Residential Risk Assessment (SOPs) - Residential Exposure Assessment Standard Operating 

Procedures Addenda 1: Consideration of Spray Drift. This document outlines the quantification 

of indirect non-occupational exposure to drift.

7.0 AGGREGATE EXPOSURE AND RISK ASSESSMENT 

In accordance with the FQPA, when there are potential residential exposures to a pesticide, 

aggregate risk assessment must consider exposures from three major routes: oral, dermal, and 

inhalation. There are three sources for these types of exposures: food, drinking water, and 

residential uses. In an aggregate assessment, exposures from relevant sources are risks 

themselves and can be aggregated. When aggregating exposures and risks from various sources, 

HED considers both the route and duration of exposure. Since there are no residential incidental 

oral (i.e., hand to mouth) exposures to cyprodinil based on existing registered products and use 

patterns, aggregate exposure from food and incidental oral exposures is not required. However, 

short-term residential handler exposures are expected based on current use patterns while 

intermediate-term residential exposures are not anticipated. Therefore, an aggregate risk 

assessment of combined short-term inhalation and oral (dietary and drinking water) exposure is 

required for residential handlers because PODs selected for these exposure routes are based on 

common toxicological effects (i.e., liver effects). The acute dietary exposure assessment used 

tolerance level residues. For the chronic dietary analysis, average field trial residues for pome 

fruit, head lettuce, leaf lettuce, spinach, tomato, and grapes and tolerance level residues for the 

remaining commodities. The acute and chronic exposure estimates from the dietary exposure 

analyses represent aggregate risk for acute and chronic exposures and are not of concern. 

7.1 Acute & Chronic Aggregate Risk

Acute and chronic aggregate exposures include food plus drinking water exposures. As 

demonstrated under Section 5.4, acute and chronic aggregate risks are not of concern.
Page 24 of 46

7.2 Short-Term Aggregate Risk

Short term aggregate exposure takes into account residential exposure (inhalation) plus average 

exposure levels to food and water (considered to be a background exposure level). The short 

term aggregate risk for residential handlers is the estimated risk associated with combined risks 

from average (chronic) food and drinking water exposures and inhalation exposures to adult 

applicators. Short term aggregate risk estimates for residential handlers are provided in Table 

7.2. Aggregate margins of exposure (MOEs) are not of concern. 

Table 7.2 Short-term Aggregate Risk Calculations for Cyprodinil Using ARI Approach1

Population Dietary Exposure Inhalation Residential 

Exposure

Aggregate ARI (food, 

water, and residential)6

MOE2 ARI3 MOE4 ARI5

Adults 7900 79 640000 640 70

1 HED is concerned if the Aggregated Risk Index (ARI) is less than 1

2 Dietary MOE = (short-term oral NOAEL)/ (chronic dietary exposure); Short-term oral NOAEL = 62 mg/kg/day; 

Chronic dietary exposure for adults 50-99 years old = 0.0078

3 Dietary ARI = (Dietary MOE dietary)/ (Target MOE); Target MOE = 100

4 Residential Inhalation MOE = (short-term inhalation NOAEL)/ (short-term inhalation exposure); Short-term 

inhalation NOAEL = 62 mg/kg/day; Short-term inhalation exposure = 0.000098 mg/kg/day

5

Inhalation ARI = (Inhalation MOE)/ (Target MOE); Target MOE = 1000

6 Aggregate ARI = 1/ [(1/Dietary ARI) + (1/Inhalation ARI)]

7.3 Intermediate-Term Aggregate Risk 

There are no residential use scenarios that will result in potential intermediate term exposure to 

cyprodinil. Therefore, an intermediate-term aggregate was not performed.

8.0 CUMULATIVE RISK

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

or revoke a tolerance, the Agency consider “available information” concerning the cumulative 

effects of a particular pesticide's residues and “other substances that have a common mechanism 

of toxicity.”

EPA does not have, at this time, available data to determine whether cyprodinil has a common 

mechanism of toxicity with other substances. Unlike other pesticides for which EPA has 

followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not 

made a common mechanism of toxicity finding as to cyprodinil and any other substances and, 

cyprodinil does not appear to produce a toxic metabolite produced by other substances which 

have tolerances in the U. S. For the purposes of this tolerance reassessment action, therefore, 

EPA has not assumed that cyprodinil has a common mechanism of toxicity with other 
Page 25 of 46

substances. For information regarding EPA’s efforts to determine which chemicals have a 

common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the 

policy statements released by EPA’s OPP concerning common mechanism determinations and 

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

EPA’s website at http://www.epa.gov/fedrgstr/EPA_PEST/2002/January/Day_16/.

9.0 OCCUPATIONAL EXPOSURE/RISK CHARACTERIZATION

9.1 Exposure Scenarios

Occupational exposure scenarios on artichoke, guava, passion fruit, feijoa, jaboticaba, wax 

jambu, starfruit, acerola, tomato (small), and stone fruit, group 12-12 have been previously 

evaluated at the same rate (i.e., 0.33 lb ai/A) for the same registered end-use products currently 

proposed (D398361, I. Nieves, 5/3/12). No estimated risks of concern were identified at label 

required PPE (i.e., filtering piece respirator). MOEs were above the Agency’s LOC (MOEs 

>LOC=1000) and ranged from 1,500 to 990,000 for short- and intermediate-term durations.

9.2 Post Application Exposure 

HED uses the term post-application to describe exposures that occur when individuals are 

present in an environment that has been previously treated with a pesticide (also referred to as reentry exposure). Such exposures may occur when workers enter previously treated areas to 

perform job functions, including activities related to crop production, such as scouting for pests 

or harvesting; or in the case of post-harvest applications, sorting and packing fruit after it has 

been treated. Post-application exposure levels vary over time and depend on such things as the 

type of activity, the nature of the crop or target that was treated, the type of pesticide application, 

and the chemical’s degradation properties. In addition, the timing of pesticide applications, 

relative to harvest activities, can greatly reduce the potential for post-application exposure.

9.2.1 Post Application Exposure Scenarios

Exposure during nut sweeping and windrowing results from contact with soil, for which transfer 

coefficients are currently unavailable. Assessment options include requesting exposure data or a 

qualitative comparison with a post-application exposure scenario assumed to result in higher 

exposure. Note that dislodgeable soil residue would be needed for an exposure assessment, as 

this would be the media contacted by worker’s performing this activity. A study monitoring 

such exposure is available (Exposure of Workers During Reentry into Pecan Groves Treated 

with Super-Tim 80WP, Griffin Corporation, 1994; EPA MRID 43557401), however has yet to be 

evaluated for derivation of transfer coefficients.

9.2.4 Restricted Entry Interval

Cyprodinil is classified as Toxicity Category III for acute dermal and eye irritation, and Toxicity 
Page 26 of 46

Category IV for skin irritation potential. Under 40 CFR 156.208 (c) (2) (iii), active ingredients 

classified as Acute III or IV for acute dermal, eye irritation and primary skin irritation are 

assigned a 12-hour REI. Therefore, the REI of 12 hours required in the registered labels is 

adequate to protect agricultural workers from post-application exposures to cyprodinil. 

10. REFERENCES

Cyprodinil. Petition Proposing a New Tolerance for the Use of Cyprodinil in/on Tree Nuts Crop Group 14-12; 

except almond, except pistachios. Summary of Analytical Chemistry and Residue Data. T. Morton, D425723, 

3/30/2016

Cyprodinil – Acute and Chronic Dietary and Drinking Water Exposure and Risk Assessment for the New Use on 

Tree Nut Crop Group 14-12; except almond, except pistachio. T. Morton, D428822, 3/30/2016

Cyprodinil. Occupational and Residential Exposure Assessment for a Proposed Uses on Cucumber (greenhouse), 

Artichoke, Guava, Passion fruit, Feijoa, Jaboticaba, Wax Jambu, Starfruit, Acerola, Pomegranate (post-harvest), 

Tomato (small), and Stone Fruit, Group 12-12. I. Nieves, D425999, 05/05/2015

Estimated Drinking Water Concentrations for Cyprodinil and its Metabolite CGA-249287 for the New Uses of the 

Chemical on Certain Stone Fruits (Crop Group 12-12), Certain Tropical Fruits, Artichoke, Cucumber (Greenhouse 

Use), and Pomegranate (Postharvest Dip) J. Melendez, D421158, 1/12/15
Page 27 of 46

APPENDICES

APPENDIX A: TOXICOLOGY DATA SUMMARY

A.1 Guideline Data Requirements

Guideline 

No. Study Type Technical MRID No. Required Submitted

870.3100

870.3150

870.3200

870.3250

870.3465

Subchronic (Oral) Toxicity - Rodent

Subchronic (Oral) Toxicity - Non-Rodent

21/28-Day Dermal Toxicity

90-Day Dermal Toxicity

90-Day Inhalation Toxicity 

Y

Y

N

N

Y1

Y

N

Y

N

N

43709027 

43709026

43709028

43709029

47526801

870.3700a

870.3700b

870.3800

Prenatal Developmental Toxicity - Rodent

Prenatal Developmental Toxicity - Non-Rodent

Reproduction and Fertility Effects

Y

Y

Y

Y

Y

Y

43709033

43709032

43709034

870.4100a

870.4100b

870.4200a

870.4200b

870.4300

Chronic (Oral) Toxicity - Rodent

Chronic (Oral) Toxicity - Non-Rodent (Dog)

Carcinogenicity - Rat

Carcinogenicity - Mouse

Combined Chronic Toxicity /Carcinogenicity

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

43737602

43709030

43737602

42710006

43737602

870.6100a

870.6100b

870.6200a

870.6200b

870.6300

870.7800

Neurotoxicity - Acute Delayed Neurotox.- Hen

Neurotoxicity - Subchronic - Hen

Neurotoxicity - Acute - Rat

Neurotoxicity -Subchronic - Rat

Developmental Neurotoxicity

Immunotoxicity

N

N

Y

Y

N

Y

N

N

Y

Y

N

Y

---

---

48304202

45906101

---

48304203

48293501

1 Based on WOE by HASPOC (TXR 0054812)

A.2 Toxicity Profiles

Table 1 Acute Toxicity of Cyprodinil.

Guideline No. Study Type MRIDs # Results Toxicity Category

870.1100 Acute Oral 43709014 LD50 = 2796 mg/kg III

870.1200 Acute Dermal 43709016 LD50 > 2000 mg/kg III

870.1300 Acute Inhalation 43709018 LC50 = 1.2 mg/L III

870.2400 Primary Eye Irritation 43709021 mild/mod irritant III

870.2500 Primary Skin Irritation 43709022 very slight irritant IV

870.2600 Dermal Sensitization 43709024

44392102

positive NA
Page 28 of 46

Table 2. Toxicity Profile of Cyprodinil Technical. 

Guideline No./ 

Study Type

MRID No. (year)/ 

Classification /Doses

Results

870.3100

90-Day oral toxicity 

(mouse)

43709027 (1991)

Acceptable/guideline

0, 500, 2000, 6000 ppm

M: 0, 73.3, 257, 849 

mg/kg/day

F: 0, 103, 349, 1121 

mg/kg/day

NOAEL = 73.3/103 mg/kg/day, M/F

LOAEL = 257/349 mg/kg/day, M/F, based on 

histopathological changes in the liver

870.3100

90-Day oral toxicity 

(rat)

43709026 (1991)

Acceptable/guideline

0, 50, 300, 2000, 12,000 

ppm

M: 0, 3.14, 19, 134, 810 

mg/kg/day

F: 0, 3.24, 19.3, 137, 803 

mg/kg/day

NOAEL =3.14 mg/kg/day

LOAEL = 19 mg/kg/day based on increased tubular kidney 

lesions in males

Non-guideline

28-Day Feeding/ 

Range Finding 

(rat)

43866301 (1989)

Acceptable/Nonguideline

0, 100, 600, 3000, 15000 

ppm

M: 10.3, 64.8, 316, 1460 

mg/kg/day

F: 0, 10.1, 62.2, 299, 

1390 mg/kg/day

NOAEL = 64.8/62.2 mg/kg/day, M/F

LOAEL = 316/299 mg/kg/day, M/F, based on lower bodyweight gains, microcytosis, increase cholesterol and 

phospholipid levels, and hepatocyte hypertrophy

Non-guideline

28-Day Gavage/ 

Range Finding 

(rat)

43737601 (1991)

Acceptable/Nonguideline

0, 10, 100 1000 

mg/kg/day

NOAEL = 10 mg/kg/day

LOAEL = 100 mg/kg/day based on increased liver weights 

and abnormalities in liver morphology

870.3150

90-Day oral toxicity 

(dog)

43709028 (1991)

Acceptable/Guideline

0, 200, 1500, 7000, 20000

ppm

M: 0, 6.07, 45.85, 210.33, 

559.66 mg/kg/day

F: 0, 6.79, 52.75, 231.93, 

580.95 mg/kg/day

NOAEL =210/232 mg/kg/day, M/F

LOAEL = 560/581 mg/kg/day, M/F, based on lower bodyweight gains and decreased food consumption in both sexes

870.3200

21/28-Day dermaltoxicity

(rat)

47526801 (008)

Acceptable/

Guideline

0, 5, 25, 125, 1000 

NOAEL = 1000 mg/kg/day

LOAEL = Not established
Page 29 of 46

Table 2. Toxicity Profile of Cyprodinil Technical. 

Guideline No./ 

Study Type

MRID No. (year)/ 

Classification /Doses

Results

mg/kg/day

870.3700a

Prenatal 

developmental

(rat) 

43709033 (1991)

Acceptable/Guideline

0, 20, 200, 1000 

mg/kg/day

Maternal NOAEL = 200 mg/kg/day

LOAEL = 1000 mg/kg/day based on lower bodyweight/body-weight gain and reduced food consumption

Developmental NOAEL = 200 mg/kg/day

LOAEL = 1000 mg/kg/day based on lower mean fetal 

weights and increased incidence of delayed ossification

870.3700b

Prenatal 

developmental

(rabbit)

43709032 (1991)

Acceptable/Guideline

0, 5, 30, 150, 400 

mg/kg/day

Maternal NOAEL = 150 mg/kg/day

LOAEL = 400 mg/kg/day based on decreased body-weight 

gain

Developmental NOAEL = 150 mg/kg/day

LOAEL = 400 mg/kg/day based on slight increase of litters 

showing extra (13th) ribs

870.3800

Reproduction and 

fertility effects

(rat)

43709034 (1993)

Acceptable/Guideline

0, 10, 100, 1000, 4000 

ppm

M: 0, 0.7, 6.7, 68, 273 

mg/kg/day

F: 0, 0.8, 8.2, 81, 326 

mg/kg/day

Maternal/Systemic NOAEL = 81 mg/kg/day

LOAEL = 326 mg/kg/day based on decreased body weight 

gain in the F0 females during the pre-mating period.

Reproductive/Developmental NOAEL = 81 mg/kg/day

LOAEL = 326 mg/kg/day based on decreased pup weights 

(F1 and F2)

870.4300

Chronic toxicity/

Carcinogenicity 

(feeding)

(rat)

43737602 (1994)

Acceptable/Guideline 

0, 5, 75, 1000, 2000 ppm

M: 0, 0.177, 2.7, 35.6, 

73.6 mg/kg/day

F: 0, 0.204, 3.22, 41.2, 

87.1 mg/kg/day

NOAEL = 2.7 mg/kg/day

LOAEL = 35.6 mg/kg/day based on degenerative liver 

lesions (spongiosis hepatis) in males

No evidence of carcinogenicity

870.4100b

Chronic toxicity

(dog)

43709030 (1991)

0, 25, 250, 2500, 15000

M: 0, 0.72, 6.87, 65.35, 

449.25 mg/kg/day

F: 0, 0.76, 6.80, 67.99, 

446.37 mg/kg/day

NOAEL = 65.63/67.99 mg/kg/day, M/F

LOAEL = 449.25/446.3, M/F, mg/kg/day based on lower 

body-weight gains and decreased food consumption and 

food efficiency

870.4200

Carcinogenicity 

(mouse)

43709031, 44417902

Acceptable/Guideline

0, 10, 150, 2000, 5000 

ppm

M: 0, 1.15, 16.1, 212.4, 

630 mg/kg/day

F: 0, 1.08, 14.7, 196.3, 

558.1 mg/kg/day

NOAEL = 16.1 mg/kg/day

LOAEL = 212.4 mg/kg/day based on a dose-related 

increase in the incidence of focal and multifocal hyperplasia 

of the exocrine pancreas in males

No evidence of carcinogenicity
Page 30 of 46

Table 2. Toxicity Profile of Cyprodinil Technical. 

Guideline No./ 

Study Type

MRID No. (year)/ 

Classification /Doses

Results

870.7800

Immunotoxicity 

(mouse)

48304203

Acceptable/Guideline

0, 500, 2000, 5000 ppm

0, 103.8, 468.3, 1245.3 

mg/kg/day

NOAEL > 1245.3 mg/kg/day

LOAEL > 1245.3 mg/kg/day 

There were no cyprodinil-related effects on absolute, 

adjusted, or relative spleen or thymus weights; no effects on 

specific activity or total activity of splenic IgM antibodyforming cells to the T cell-dependent antigen sRBC. 

Cyprodinil attributed effects was higher mean absolute, 

relative (to body weight), and adjusted liver weights at 

HDT.

870.6200a

Acute Neurotoxicity

48304202

Acceptable/Guideline

0,200, 600, 2000 mg/kg

/day

NOAEL = 200 mg/kg/day

LOAEL = 600 mg/kg/day

Based on clinical signs of toxicity and low motor activity 

and reversible hypothermia, no neuropathic changes were 

noted at any dose level.

870.6200b

Subchronic 

Neurotoxicity

45906101

Acceptable/Guideline

0,80, 800, 8000 ppm 

M: 0, 5.8, 54.5, 601

F: 0, 6.3, 58.7, 631 

mg/kg/day

Neurotoxicity NOAEL > 601 mg/kg/day M; 631 mg/kg/day 

F

Neurotoxicity LOAEL > 601 mg/kg/day M; 631 mg/kg/day 

F

Systemic toxicity NOAEL = 54.5 mg/kg/day M; 58.7 

mg/kg/day F 

Systemic LOAEL = 601 mg/kg/day M; 631 mg/kg/day F

based on decreased body weight gain and microscopic 

lesions in the liver (hepatocellular hypertrophy), kidney 

(tubular casts) and thyroid gland (follicular cell 

hypertrophy)

870.5100

Gene Mutation -

Bacteria

43709037 (1990)

Acceptable/Guideline

In a reverse gene mutation assay with Salmonella 

typhimurium/Escherichia coli, cyprodinil was negative up 

to concentrations that produced reproducible cytotoxicity 

(≥1250 μg/plate +/-S9) for the majority of strains. 

Compound insolubility was reported at ≥313 μg/plate.

870.5300

Gene Mutation -

In vitro mammalian 

cell

43709036 (1990)

Acceptable/Guideline

In a Chinese hamster V79 cell HGPRT forward gene 

mutation assay, cyprodinil was negative up to cytotoxic 

concentrations (>96.0 μg/mL with S9) (>24 μg/mL without 

S9).

870.5375

Cytogenetics/

In vitro

Chromosomal 

Aberration

43709038 (1991)

Acceptable/Guideline

In an in vitro assay for chromosome aberrations in Chinese 

hamster ovary (CHO) cells, cyprodinil cytotoxicity, as 

indicated by decreased mitotic indices (MIs) and/or effects 

on cell monolayers, was demonstrated at  50 μg/ml (-S9) 

(18-hour treatment) and  25 μg/ml (-S9) (4-hour 

treatment). With S9 activation, doses  50 μg/ml were 

severely cytotoxic. Although suppression of the MI in cells 

exposed to 50 μg/ml +S9 (and allowed a 39-hour recovery) 

was 14 %, it was concluded that testing at a higher level 

would likely show severe effects. Therefore, the 50 μg/ml 

S9-activated dose in the prolonged recovery experiment 
Page 31 of 46

Table 2. Toxicity Profile of Cyprodinil Technical. 

Guideline No./ 

Study Type

MRID No. (year)/ 

Classification /Doses

Results

should be considered the highest subcytotoxic 

concentration. The positive controls induced the 

appropriate response. There was, however, no indication 

that cyprodinil induced a clastogenic effect.

870.5395

Cytogenetics/

In vivo bone marrow 

micronucleus

43709039 (1990)

Acceptable/Guideline

In an in vivo bone marrow micronucleus assay, cyprodinil 

was negative when administered orally (gavage) at 5000 

mg/kg (HDT) to both sexes of Tif:MAGF mice. No signs 

of overt toxicity or clear evidence of cytotoxicity for the 

target organ were noted at any dose or sacrifice time.

870.5550 

UDS

43709035 (1991)

Acceptable/Guideline

In an UDS assay in primary rat hepatocytes, cyprodinil was 

negative up to a cytotoxic concentration (80 μg/mL) 

870.7485

Metabolism and 

pharmacokinetics

43709040 (1992)

Acceptable/Guideline

Single oral doses (0.5 or 100 mg/kg bw) of phenyl or 

pyrimidyladministered to Tif:RAIf(SPF) rats, with one low-dose 

group receiving unlabeled

2 weeks prior to treatment with radiolabelled compound. 

Absorption was very rapid (tcmax= 0.3 hours) with rapid 

clearance (tcmax/2=1.2 hours). A minimum of 75% of the 

administered dose was absorbed. Excretion was rapid and 

almost complete, with urine as the principle route of 

excretion (48-68%), and >90% of the administered dose 

detected in the urine and feces within 48 hours. Excretion, 

distribution and metabolite profiles were essentially 

independent of dose level, pretreatment, and type of label, 

although there were some quantitative differences sexdependent qualitative differences in two urinary metabolite 

fractions.

870.7485

Metabolism and 

pharmacokinetics

43709041 (1992)

Acceptable/guideline

Must be considered with MRID 43709040.

Excreta (Group D1 and D2) and bile (Group G1) from 

radiolabelled CGA 219417-treated Tif:RAIf(SPF) rats of a 

previous ADME study (MRID 43709040) were used to 

characterize, isolate and identify CGA 219417 metabolites 

(MRID 43709041). Eleven metabolites were isolated from 

urine, feces and bile, and the metabolic pathways in the rat 

were proposed. All urinary and biliary metabolites (with 

the exception of 7U) were conjugated with glucuronic acid 

or sulfonated, and excreted. CGA 219417 was almost 

completely metabolized by hydroxylation of the phenyl ring 

(position 4) or pyrimidine ring (position 5), followed by 

conjugation. An alternative pathway involved oxidation of 

the phenyl ring followed by glucuronic acid conjugation. A 

quantitative sex difference was observed with respect to 
Page 32 of 46

Table 2. Toxicity Profile of Cyprodinil Technical. 

Guideline No./ 

Study Type

MRID No. (year)/ 

Classification /Doses

Results

sulfonation of the major metabolite that formed 6U. The 

monosulfate metabolite (1U) was predominant in females, 

whereas equal amounts of mono- and disulfate (6U) 

conjugates were noted in males. Most of the significant 

metabolites in feces were exocons of biliary metabolites 

(2U, 3U, 1G). These were assumed to be deconjugated in 

the intestines, partially reabsorbed into the general 

circulation, conjugated again, and eliminated renally. The 

major metabolic pathways of CGA 219417 were not 

significantly influenced by the dose, treatment regimen, or 

sex of the animal.

870.7600

Dermal Absorption 

(rat)

45906102 (1999)

In review

6 μg/cm2 or 870 μg/cm2

In a dermal absorption study with CGA 219417 formulated 

as SWITCH 62.5 WG in the rat, the maximum systemic 

absorption was 21.71% (at 24 hours). An additional 12% of 

the applied dose (that is potentially available for absorption) 

remained on the treated skin at 24 hours.

A.3 Toxicological Endpoints

A.3.1 Acute Reference Dose (aRfD) – All Populations

Selected Study: Acute Neurotoxicity Rat; MRID 48304202

Dose and Endpoint for Establishing a POD: NOAEL = 200 mg/kg from an acute neurotoxicity 

study based on LOAEL of 600 mg/kg showing clinical signs (hunched posture, piloerection, and 

reduced responsiveness to sensory stimuli, reduced motor activity and hypothermia). 

Uncertainty Factor (UF): 100x (10x for interspecies and 10x for intraspecies variation)

aRfD = aPAD(all Populations) =

200 mg/kg (NOAEL)

100 (UF)

= 2 mg/kg

[Note: The acute RfD has been revised from previous risk assessments based on receipt and 

review of an acute neurotoxicity study and subsequent reevaluation of available data.]

A.3.2 Chronic Reference Dose (cRfD) - All Populations

Selected Study: Combined Chronic Toxicity/Carcinogenicity-Rat; MRIDs 43737602, 44429401 
Page 33 of 46

and 44417902

Dose and Endpoint for Establishing a POD: 2.7 mg/kg/day (NOAEL) based on the 

histopathological alterations in the liver (spongiosis hepatis) in males at 35.6 mg/kg/day

(LOAEL).

Uncertainty Factor (UF): 100x (10x for interspecies and 10x for intraspecies variation,)

Comments about Study/Endpoint: The selected NOAEL is the lowest NOAEL observed in the 

most sensitive species following long-term exposure.

cRfD = cPAD(all Populations) =

2.7 mg/kg (NOAEL)

100 (UF)

= 0.027 mg/kg/day

A.3.3 Inhalation Exposure (Short to Intermediate Term)

A No Observable Adverse Effect Level (NOAEL) of 62 mg/kg/day was identified for short to 

intermediate-term inhalation risk assessments. The NOAEL is based on decreased body weight 

gains, microcytosis, increased cholesterol and phospholipid levels, and hepatocyte hypertrophy 

seen at the Lowest Observable Adverse Effect Level (LOAEL) of 299 mg/kg/day from a 28-Day 

Feeding/Range-finding study on rats with cyprodinil.

 

A.4 EXECUTIVE SUMMARIES FOR SUPPORTING TOXICITY STUDIES

A.4.1 Subchronic Toxicity

870.3100 90-Day Oral Toxicity – Rat MRID 43709026

In a subchronic toxicity study (MRID 43709026), CGA 219417 (cyprodinil; 99.5% ai; Lot No. P

912004) was administered in the diet to 20 rats/sex/dose at dose levels of 0 or 12000 ppm (0 or

810 mg/kg/day, respectively, for males; 0 or 803 mg/kg/day, respectively, for females), and to 10

rats/sex/dose at dose levels of 50, 300, or 2000 ppm (3.14, 19.0, or 134 mg/kg/day, respectively,

for males; 3.24, 19.3, or 137 mg/kg/day for females) for 90 days. All animals were sacrificed at

90 days except for 10 control and 10 2000 ppm rats/sex which were sacrificed after a 4 week

recovery period. 

At 50 ppm and above there were - increased cholesterol and phospholipid levels in females (18% 

for both) which increased with increasing dose [cholesterol - 300 ppm (20%), and male and 

female 2000(37-48%) and 12000 (85-105%) ppm groups; phospholipid -300 ppm (23%) group, 

and male and female 2000 (36%) and 12000(71-90%) ppm groups.]
Page 34 of 46

At 300 ppm and above there was - increased alkaline phosphatase in the male with females 

affected at 12000 ppm. Liver abnormalities at 300 ppm included hepatocyte hypertrophy and 

hepatocyte necrosis observed in male rats, with females affected at 2000 and 12000 ppm. Kidney 

abnormalities included a low incidence (0, 0, 10, 10, 20% for males only, control to high dose) 

vacuolization of the epithelium of the proximal convoluted tubules, and chronic tubular lesions 

(0, 0, 30, 50, 80% for males and 20, 20, 0, 50, 80% for females, control to high dose), in male 

and/or female rats at 300 ppm. The tubular lesions were more frequent at 2000 and 12000 ppm. 

Enlarged (hypertrophic) pituitary cells in the adenohypophysis were observed in males in the 300 

ppm group, and males and females in the 2000 and 12000 ppm groups. “Minimal” to “moderate” 

hypertrophy of the follicular epithelia of the thyroid was noted in males in the 300, 2000, and 

12000 ppm groups. 

At 2000 ppm and above there were additional hepatic lesions consisting of “sharply demarcated 

membranous structures containing a vacuolated eosinophilic material” (“cytoplasmic inclusion 

bodies”) and renal chronic tubular lesions in 50 % of the males and females. There was an 

increase in protein and globulin levels in the males. Relative liver weights were higher for male 

and female rats in the 2000 and 12000 ppm groups. Relative thyroid weights were higher for 

male rats in the 2000 ppm group, and male and female rats in the 12000 ppm groups.

At 12000 ppm there was - a decrease in body weight gains of female and male rats (20-26% 

lower than controls at the termination of the study). Hemoglobin and hematocrit values were 

lower, albumin levels higher and glucose levels lower in the males. Leukocyte counts and 

gamma glutamyl transpeptidase activity levels were higher in the male and female groups. 

Additional renal lesions included nephrocalcinosis (0, 0, 10, 0, 50%, control to high dose in 

males only). Relative kidney weights were also higher for high dose males. The relative weights 

of the adrenals in males were greater than the controls, with “minimal” increases in the amount 

of fat vesicles in the adrenal cortex noted in a majority of these animals. 

Following a 4-week post treatment recovery period (using 0 and 12000 ppm rats only), all 

hematological and blood chemistry differences lost significance, with the exception of 

cholesterol and phospholipid concentrations in females. The relative weights of the liver and 

thyroid glands of males in the 12000 ppm groups remained greater than those of the control 

group, but with the exception of chronic tubular kidney lesions, the prevalence of all microscopic 

abnormalities was reduced. 

Most changes at 50 were not adequate to establish an LOAEL therefore the LOAEL is 300 ppm 

(19 mg/kg body weight/day) for rats, based on increased chronic tubular kidney lesions in males. 

The NOAEL is 50 ppm (3.14 mg/kg/day).

This subchronic toxicity study is classified acceptable (guideline), and satisfies the guideline 

requirement for a subchronic oral study (82-1) for rodents.

870.3100 90-Day Oral Toxicity – Mouse MRID 43709027
Page 35 of 46

A 3-month study (MRID 43709027) was carried out in Tif:MAGf(SPF) albino mice where 

animals (10 mice/sex/dose) were fed diets containing 0, 500,2000 or 6000 ppm (actual 

concentrations: males - 0, 73.3, 257 or 849 mg/kg/day; females - 0, 103, 349 or 1121 mg/kg/day) 

of CGA 219417 technical (99.5% a.i., Batch No- P 912004). There was no effect on mortality, 

or hematology parameters, and no clinical sighs of toxicity. Treatment-related effects included 

increased absolute and relative liver weights (112-118 %) in 6000 ppm males, and hepatic 

changes in mid- and high dose males and females that consisted of multifocal hepatocyte 

necrosis in 2000 and 6000 ppm males (30 % as compared to 0 in the control and low dose 

groups) and glycogen depletion in 2000 and 6000 ppm females (10, 10, 70 and 100% from 

controls to high dose). The LOAEL is 2000 ppm based on histopathological changes in the liver. 

The NOAEL is 500 ppm (malts - 73.3; females - 103 mg/kg/day). This study is acceptable 

(guideline) even though it is listed as a range-finding study. It satisfies the guideline requirement 

for a subchronic study in the rodent (82-1(a)).

870.3100 90-Day Oral Toxicity – Dog MRID 43709028

A 3-month study was carried out in Beagle dogs where animals (4/sex/dose) were fed diets 

containing 0, 200, 1500, 7000 or 20000 ppm (actual concentrations: males - 0, 6.07, 45.87, 

210.33 or 559.66 mg/kg/day; females - 0, 6.79, 52.75, 231.93 or 580.95 mg/kg/day) CGA 

219417. There was no effect on mortality, or clinical chemistry parameters. Vomiting was 

observed in all high-dose females during the first week of treatment, and an increase in mean 

platelet count was noted in high-dose females at weeks 7 and 13. Lower bodyweight gains (64-

76%) and decreased food consumption were apparent in high-dose males and females throughout 

the study period. There was a transient decrease in bodyweight gain and food consumption in 

7000 ppm females, which was noted after the first week of treatment only, and this was 

considered non-adverse. The LOAEL is 20,000 ppm (males -560, females -581 mg/kg/day) 

based on lower bodyweight gains and decreased food consumption in both sexes. The NOAEL is 

7000 ppm (males -210, females - 232 mg/kg/day).

870.3200 28 Day Dermal Toxicity – Rat MRID 47526801

In a 28-day dermal toxicity study (MRID 47526801), Cyprodinil (99%, P012011) was applied to 

the shaved skin of 50 HanRCC Wistar Rats/sex/dose at dose levels of 0 (vehicle control), 5, 25, 

125 and 1000 mg/kg bw/day, 6 hours/day for 5 days/week during a 28-day period, for a total 

treatment of 20 days.

The following parameters were measured: general clinical observations, detailed behavioral 

observations. Body weight and food consumption, functional observational battery including grip 

strength and locomotor activity. Ophthalmoscopic examination, hematology and clinical 

chemistry. Organ weights, macroscopic and histopathological examination of selected organs.

No treatment related effects were seen at any concentration when measuring body weight gain, 

food consumption, hematological parameters, clinical chemical parameters, organ weights, gross 

or histopathology. 
Page 36 of 46

Skin lesions characterized by fissures, scabs, erythema, hair loss, sores, were common in all 

experimental groups and the control group, probably resulting from shaving the skin to apply the 

test article or vehicle.

The NOAEL is 1000 mg/kg/day. The LOAEL is not established.

This 28-day dermal toxicity study in the HanRCC Wistar rats is acceptable guideline and 

satisfies the guideline requirement for a 28-day dermal toxicity study (OPPTS 870.3200; OECD 

410) in rats. 

A.4.2 Prenatal Developmental Toxicity - Rat

870.3700a Prenatal Developmental Toxicity Study – Rat MRID 43709033

In a developmental toxicity study (MRID No. 43709033), CGA 219417 technical (99.5% a.i., 

Batch No. P912004) was administered in 3% aqueous corn starch suspension by oral gavage to 

20-23 Tif:RAIf(SPF) females albino rats per dose of 0, 20, 200 or 1000 mg/kg/day or gestation 

days 6-15. Treatment related findings included reduced locomotor activity (one high dose 

female), significantly lower mean body weight (16%), body weight gain (65%), gravid uterine 

weight (18%), and mean carcass weight (10%), and significantly decreased food consumption 

(32-42%) in high-dose females. The LOAEL for maternal toxicity is 1000 mg/kg/day based on 

lower body weight/body weight gain and reduced food consumption. The NOAEL was 200 

mg/kg/day. There were significantly lower mean fetal weights (11%) in the high-dose group 

compared to controls as well as a significant increase in skeletal anomalies in the high-dose 

group relative to the control, which was due to abnormal ossification (4/20 litters in the high 

dose group compared to 0 in any other group), primarily as absent or reduced metacarpal 5 

ossification. The skeletal anomalies/variations were considered to represent a transient 

developmental delay that occurs secondary to the maternal toxicity noted in the high-dose group. 

The LOAEL for developmental toxicity is 1000 mg/kg/day based on lower mean fetal weights 

and an increased incidence of delayed ossification. The NOAEL for developmental toxicity is 

200 mg/kg/day. This study is classified acceptable (guideline) and satisfies the guideline 

requirement for a developmental study in the rat [(OPPTS 870.3700 (83-3a)].

870.3700b Prenatal Developmental Toxicity Study – Rabbit MRID 43709032

In a developmental toxicity (MRID No. 43709032), CGA 219417 technical (99 5%a.i., Lot# 

P9t2004) was administered in 3% aqueous corn starch suspension to 19 inseminated female 

rabbits (Russian Chbb:HM, SPF)/dose by gavage at dose levels of 0,5; 30; 150, or 400 

mg/kg/day from days 7 through 19 of gestation. Mean maternal body weight gain (p <0.01) and 

food consumption (not significant) decreased, mainly during the first week of treatment in the 

400 mg/kg/day group. Mean body weight gain was 622% less than controls (p <0.01) in this 

group between days 7 and 13 of gestation. The maternal LOAEL is 400 mg/kg/day, based on 

decreased body weight gain. The maternal NOAEL is 150 mg/kg/day. Fetuses at the 400 

mg/kg/day dose exhibited indications of an increased incidence of a 13th rib (not significant). 
Page 37 of 46

Although there were indications of developmental delays in fetal skeletons, such as poor or 

absent ossification of the sternebrae and metacarpals at all dose levels, only the extra rib is likely 

to be compound related. Uni- or bilateral hyperflexion of the carpal joint at the 400 and 150 

mg/kg/day doses (not significant) was not associated with the skeletal changes. The fetal 

developmental LOAEL is 400 mg/kg/day based on a slight increase of litters showing extra 

(13th) ribs. The fetal developmental NOAEL is 150 mg/kg/day. The developmental toxicity 

study in the rabbit is classified acceptable (guideline) and satisfies the guideline requirement for 

a developmental toxicity study (OPPTS 870.3700; §83-3 (b)) in rabbit.

A.4.3 Reproductive Toxicity

870.3800 Reproduction and Fertility Effects – Rat MRID 43709034

In a two-generation reproduction study (MRID No. 43709034), Tif:RAIf rats (30 rats/sex/dose), 

with one litter per generation received CGA219417 (99.5 % a.i., Batch No. P912004) in the diet 

at doses of 0, 10, 100, 1000 or 4000 ppm (actual intake, males: 0, 0.7, 6.7, 68 or 273; females: 0,

0.8, 8.2, 81 or 326 mg/kg/day) for a 10 week pre-mating period. Signs of toxicity at 4000 ppm 

consisted of lower body weights (12.5%) in the F0 females after the pre-mating period. Increased 

liver weight in 1000 (marginal) and 4000 ppm males and females was not supported by 

histopathological findings. Although these were considered treatment related, they were 

considered to be non-adverse. The LOAEL for maternal systemic toxicity is 4000 ppm (about 

326 mg/kg/day) based on lower body weights in the F0 females during the pre-mating period. 

The NOAEL for maternal systemic toxicity was 1000 ppm (about 81 mg/kg/day). HIARC 

determined that premating body weight gain (not absolute body weight) should be used as the 

basis of the NOAEL. Signs of reproductive toxicity included significantly lower F1 and F2 pup 

weights in the high-dose group during lactation, which continued to be lower than controls postweaning and after the pre-mating period (examination in F1 generation only). The LOAEL for 

reproductive/developmental toxicity is 4000 ppm (about 326 mg/kg/day) based on decreased pup 

weights (F1 and F2). The NOAEL for reproductive toxicity is 1000 ppm (about 81 mg/kg/day).

The two-generation reproduction study in the rat is classified acceptable (guideline) and satisfies 

the guideline requirement for a two-generation reproduction study (OPPTS 870.3800; §83-4) in 

rat.

A.4.4 Chronic Toxicity

870.4100a (870.4300) Combined Chronic Toxicity/Carcinogenicity – Rat MRIDs 

43737602, 44429401, 44417902

In a 24-month chronic toxicity/oncogenicity study (MRID No: 43737602, 44429401,44417902), 

Tif:RAIf rats (50 rats/sex/dose - carcinogenicity portion, plus 20/sex/dose laboratory 

investigations) were fed diets containing 0, 5, 75, 1000 or 2000 ppm (actual concentrations: 

males 0, 0.177, 2.7, 35.6 or 73.6 mg/kg/day; females 0, 0.204, 3.22, 41.2 or 87.1 mg/kg/day) 

CGA 219417(99.2-99.6% a.i. Batch No. P 912006). An additional 10/sex/dose were fed test diets 

for 12 months (interim sacrifice). Survival was slightly lower in males at 2000 ppm relative to 
Page 38 of 46

control and other dose groups (54, 50, 50, 49, and 44%, from controls to high dose). 

Toxicologically significant findings included increased liver weights in high-dose males (10.7%) 

and a dose-related increase in the incidence of spongiosis hepatis in the liver of 1000 and 2000 

ppm males (5, 5, 3, 17 and 23 %, controls to high dose). For chronic toxicity, the NOAEL was 

75 ppm (2.7 mg/kg/day) and the LOAEL was 1000 ppm (35.6 mg/kg/day) based on degenerative 

liver lesions (spongiosis hepatis) in males. This chronic carcinogenicity study in the rat is 

acceptable (guideline).

870.4100b Chronic Toxicity - Dog MRID 43709030

A 1-year study (MRID 43709030) was carried out in Beagle dogs where animals (4/sex/dose) 

were fed diets containing 0,25,250,2500 or 15,000 ppm (actual concentrations: males -0, 0.72, 

6.87, 65.63 or 449.25; females -0, 0.76, 6.80, 67.99 or 446.37 mg/kg/day) CGA 219417 (99.6% 

a.i., Batch No. P 912006).

There was no effect on mortality, hematological, or clinical chemistry parameters, and no clinical 

signs of systemic toxicity. Throughout the first half of the study, lower bodyweight gains (31-

38% less) (attributable primarily to 2/4 of each sex) and decreased food consumption were 

apparent in high-dose males and females; with reduced food efficiency in high dose males and 

females in the latter part of the study. The LOEL is 15,000 ppm (males - 449.25, females 446.37 

mg/kg/day) based on lower bodyweight gains and decreased food consumption and food 

efficiency. The NOAEL is 2500 ppm (males - 65.63, females - 67.99 mg/kg/day). This study is 

classified as acceptable (guideline) and satisfied the guideline requirement for a chronic oral dog 

study (870.4100b).

A.4.5 Carcinogenicity

870.4200a Carcinogenicity/Chronic Study – Mice MRID 43709031

An 18-month oncogenicity study was carried out in Tif:MAGf(SPF) albino mice where animals 

(50 mice/sex/dose - carcinogenicity portion, plus 10/sex/dose - hematology) were fed diets 

containing 0, 10, 150, 2000 or 5000 ppm (actual concentrations: males - 0, 1.15, 16.1, 212.4 or 

630; females - 0, 1.08, 14.7, 196.3 or 558.1 mg/kg/day) of CGA 219417 (99.0-99.5% a.i., Batch 

No. P912006). There was no effect on mortality, or hematology parameters, and no clinical signs 

of toxicity. Treatment-related effects included lower bodyweight and bodyweight gain (males -

10%, females - 27%) at 5000 ppm, reduced food efficiency and increased relative liver weights 

(16%) in high-dose males and females, and a dose-related, increase in minimal to marked 

pancreatic acinar cell hyperplasia in 2000 and 5000 ppm males (8, 8, 10, 16, 28% incidence, 

from control to high dose). The LOAEL is 2000 ppm (males - 212.4 mg/kg/day) based on a 

dose-related increase in the incidence of focal, and multifocal hyperplasia of the exocrine 

pancreas in. males. The NOAEL was 150 ppm (males - 16.1 mg/kg/day). This study was tested 

to adequate levels based on signs of toxicity in males at 2000 ppm and female at 5000 ppm. This 

chronic carcinogenicity study in the mouse is acceptable/guideline.
Page 39 of 46

A.4.6 Mutagenicity

Gene Mutation

Guideline # 870.5100 Bacterial assay

MRID 43709037 

Acceptable/Guideline

Guideline #870.5300, In vitro 

mammalian cell gene mutation test

MRID 43709036

Acceptable Guideline

Not mutagenic

Not mutagenic in the presence or absence of S9-activation up to cytotoxic 

concentrations (>96.0 μg/mL with S9) (>24 μg/mL without S9).

Cytogenetics

Guideline # 870.5375, 

Cytogenetics/In vitro Chromosomal 

Aberration

MRID 43709038

Acceptable Guideline

Guideline #870.5395 

Cytogenetics/In vivo bone marrow 

micronucleus MRID 43709039

Acceptable Guideline

cyprodinil gave negative results up to cytotoxic concentrations 

negative

A.4.7 Neurotoxicity

870.6100 Delayed Neurotoxicity Study – Hen - NA

870.6200a Acute Neurotoxicity Screening Battery MRID 48304202

In an acute neurotoxicity study in mice (MRID 48304202) CGA 219417 technical (batch #: 

P.012011 a light beige powder with a purity of 99.2%) was administered to rats to assess the 

potential acute neurotoxicity and to estimate the NOAEL of exposure of the test compound, a 

fungicide, when administered by gavage. The test article was administered by gavage as single 

oral dose of 0, 200, 600, and 2000 mg/kg to a total of 80 Sprague-Dawley-derived rats (10 males, 

and 10 females, per dose group). Mortality, clinical signs, body weight, and food consumption 

were monitored throughout the study. A 'Functional Observational Battery'

(FOB) was performed pretest, at the time of peak effect (2 hours post-dose, and on test days 8 

and 15. At necropsy, animals were sacrificed by in situ perfusion. The brain, spinal cord, 

peripheral nerves and eyes were collected, prepared for histological evaluation and 5 animals per 

sex each of the control and top-dose group (experimental group I) examined microscopically. 

Two animals of group 3 died spontaneously. The male, found dead on test day 2, was most likely 

miss-intubated. For the female, which was found dead on test day 18, the cause of death could 

not be identified. Body weight gain and food consumption were not affected by treatment. 

Observations and functional tests conducted as part of the FOB showed relevant changes at the 
Page 40 of 46

time of peak effect only. In females of group 3 and 4 reduced activity, hunched posture, 

piloerection, and increased responsiveness to sensory stimuli were observed with hunched 

posture seen also in few group 2 females. In females of group 3 and 4, signs lasted up to test day 

4 and were considered to indicate toxicity. A dose related decrease in body temperature was 

observed, being minimal in animals of group 2. Changes in motor activity parameters were 

limited to the time of peak effect. In group 4 males and in females of group 3 and 4 horizontal 

and vertical activity parameters were reduced. Macroscopic and microscopic examination of the 

multiple areas of the central and peripheral nervous system, the eyes, optic nerves, and skeletal 

muscle of the male and female, control and high-dose animals of experimental group I didn’t 

reveal any treatment-related neuropathic changes. Based on these data it was concluded that 

CGA 219417 tech., when administered to rats at a single oral dose of 200, 600 or 2000 mg/kg, 

induced a dose-related hypothermia. Due to its full reversibility in all dose groups, the slightly 

reduced body temperature in low-dose animals was not considered as adverse. A dose of 200 

mg/kg thus represented the NOAEL for this study. The LOAEL was deemed to be 600 mg/kg 

and greater induced signs of toxicity at the time of peak effect which disappeared within a few 

days as well. In the absence of any permanent or delayed functional changes and of neuropathic 

changes in the central and peripheral nervous system, CGA 219417 tech was considered not to 

be neurotoxic up to the near lethal dose of 2000 mg/kg.

870.6200b Subchronic Neurotoxicity Screening Battery MRID 45906101

In a subchronic neurotoxicity study (MRID 45906101) CGA 219417 technical (99.2% a.i., batch 

#: P. 012011) was administered to 10 Tif: RAIf Sprague-Dawley derived albino rats/sex/group at 

dose levels of 0, 80, 800, or 8000 ppm (equivalent to 0, 5.8, 54.5, and 601 mg/kg bw/day in 

males and 0, 6.3, 58.7, and 631 mg/kg bw/day in females) for 90 consecutive days. 

Neurobehavioral assessment (functional observational battery and motor activity testing) was 

performed in 10 animals/sex/group pre-exposure and at weeks 4, 8, and 13. At study termination, 

10 animals/sex/group were euthanized and perfused in situ for neuropathological examination. 

Of the perfused animals, 5/sex/group of the control and high-dose groups were subjected to 

histopathological evaluation of brain and peripheral nervous system tissues. In addition, the 

liver, kidneys, thyroid gland, and pituitary were collected from all animals and examined 

microscopically. 

There were no treatment related effects on mortality, clinical signs, or gross or histological 

neuropathology. FOB and motor activity testing revealed no treatment related effects up to the 

highest dose tested (8000 ppm). In high-dose animals, absolute body weight was significantly or 

slightly less than the controls throughout the study due to reduced weight gain by the treated 

animals. Cumulative weight gain by the high-dose groups was significantly less than that of the 

control groups during weeks 1-6 and 8 for males and weeks 1, 4, and 11-13 for females. The 

most pronounced effect on weight gain was during the first week of the study when high-dose 

males and females gained 59% and 38%, respectively, of the control levels. Overall weight gain 

by the high-dose males and females was 87% and 79%, respectively, of the controls. Food 

consumption by the high-dose animals was reduced only at week 1 to 89% and 77% of controls 

for males and females, respectively. In the high-dose group, absolute and relative liver weights 

were increased in both sexes (126-138% and 121-125% of controls for males and females, 
Page 41 of 46

respectively). Absolute and relative kidney weights were elevated in high-dose females (112-

118% of controls).

Microscopic examination revealed an increase in the incidence, but not in severity, at the high 

dose of lesions in the liver, kidney, and thyroid. Hepatocellular hypertrophy in the liver was 

observed in 5/10 high-dose males compared with 1/10 controls and in 5/10 high-dose females 

compared with 0/10 controls; this is an adaptive response. Tubular lesions or tubular casts were 

seen in the kidneys of 4/10 high-dose males and 5-7/10 high-dose females vs 0-2/10 animals in 

the control groups. Hypertrophy of the follicular epithelial cells in the thyroid gland occurred in 

5/10 high-dose males and 4/10 high-dose females compared with only 1/10 control males.

Based on the results of this 90-day subchronic oral neurotoxicity study, the neurotoxicity 

LOAEL for CGA 219417 technical in male and female rats was not identified, while the NOAEL 

is 8000 ppm (601 mg/kg bw/d in males; 631 mg/kg bw/d in females).

The systemic toxicity LOAEL for CGA 219417 technical in male and female rats is 8000 ppm 

(601 mg/kg bw/d in males and 631 mg/kg bw/d in females) based on decreased body weight 

gain, tubular casts in the kidneys, and thyroid follicular cell hypertrophy. The NOAEL is 800 

ppm (54.5 mg/kg bw/d in males and 58.7 mg/kg bw/d in females).

The study is classified as Acceptable/Guideline and satisfies the guideline requirement for a 

subchronic neurotoxicity study in rats (870.6200b). 

A.4.8 Metabolism

870.7485 Metabolism – Rat 

Study 1

In a metabolism study ( MRID 43709040), single oral doses (0.5 or 100 mg/kg bw) of phenyl or 

pyrimidyl-radiolabelled CGA-219417 (purity  98%) were administered to Tif:RAIf(SPF) rats, 

with one low-dose group receiving unlabeled CGA 219417 (purity  99%) for 2 weeks prior to 

treatment with radiolabelled compound. Absorption was very rapid (tcmax= 0.3 hours) with rapid 

clearance (tcmax/2=1.2 hours). A minimum of 75% of the administered dose was absorbed. A 

biphasic first order kinetics was observed for radioactivity depletion, with a duration of 0.3-1.2 

hours for the first phase, and 27-65 hours for the second phase. Excretion was rapid and almost 

complete, with urine as the principle route of excretion (48-68%), and >90% of the administered 

dose detected in the urine and feces within 48 hours. Tissue residues declined rapidly, with the 

highest concentrations ( 1.8 ppm) found in kidneys, liver, lungs, spleen, thyroid, whole blood, 

and carcass. The urine, fecal, and bile metabolite patterns were complex, with 8, 8 and 9 defined 

metabolite fractions, respectively. Unchanged parent compound was detected in feces extract 

only. Excretion, distribution and metabolite profiles were essentially independent of dose level, 

pretreatment, and type of label, although there were some quantitative differences sex-dependent 
Page 42 of 46

qualitative differences in two urinary metabolite fractions.

This study is classified as acceptable (guideline) and when taken together with study (MRID 

43709041) satisfies the guideline requirement for a metabolism study in rats (85-1).

Study 2

Excreta (Group D1 and D2) and bile (Group G1) from radiolabelled CGA 219417-treated 

Tif:RAIf(SPF) rats of a previous ACME study (MRID 43709040) were used to characterize, 

isolate and identify CGA 219417 metabolites (MRID 43709041). Eleven metabolites were 

isolated from urine, feces and bile, and the metabolic pathways in the rat were proposed. All 

urinary and biliary metabolites (with the exception of 7U) were conjugated with glucuronic acid 

or sulfonated, and excreted. CGA 219417 was almost completely metabolized by hydroxylation 

of the phenyl ring (position 4) or pyrimidine ring (position 5), followed by conjugation. An 

alternative pathway involved oxidation of the phenyl ring followed by glucuronic acid conjugation. 

A quantitative sex difference was observed with respect to sulfonation of the major metabolite that 

formed 6U. The monosulfate metabolite (1U) was predominant in females, whereas equal amounts 

of mono- and disulfate (6U) conjugates were noted in males. Most of the significant metabolites 

in feces were exocons of biliary metabolites (2U, 3U, 1G). These were assumed to be 

deconjugated in the intestines, partially reabsorbed into the general circulation, conjugated again, 

and eliminated renally. The major metabolic pathways of CGA 219417 were not significantly 

influenced by the dose, treatment regimen, or sex of the animal.

This study is classified as acceptable (guideline) and when taken together with study (MRID 

43709040) satisfies the guideline requirement for a metabolism study in rats (85-1).

A.4.9 Immunotoxicity

870.7800 Immunotoxicity – Mice MRID 48304203

In an immunotoxicity study (MRID 48304203), the test substance cyprodinil was offered ad 

libitum in the diet of Crl:DC1 (ICR) female mice, for 28 consecutive days to three groups 

(Groups 2-4) at dietary concentrations of 500, 2000, and 5000 ppm, respectively. Mice in Group 

5 were administered the positive control substance, cyclophosphamide (CPS), via IP (50 

mg/kg/day) for four consecutive days (study days 24-27). The vehicle and positive control 

groups (Groups 1 and 5, respectively) were offered a basal diet on a comparable regimen as the 

cyprodinil-treated groups. In addition, all mice were immunized with sheep red blood cells 

(sRBC) on study day 24. All animals were euthanized on day 28. Mortality and morbidity were 

observed twice daily in all animals, while clinical exams were performed once a day. More 

detailed physical exams were performed once a week and the day of necropsy. Single animal 

body weights were recorded two times a week and food consumption was recorded weekly. 

Complete necropsies were conducted on all animals. Organs (liver, spleen, and thymus) were 

collected and weighed at scheduled necropsy. Spleens were analyzed by ImmunoTox®,Inc . for 

IgM antibody forming cells directed towards the sRBC determination. Test substances were 0, 
Page 43 of 46

103.8, 468.3, and 1245.3mg/kg/day or 0, 500, 2000, and 5000ppm, respectively, for the entire 4-

week study. All animals survived to necropsy. There were no test substance-related clinical 

observations, no effects on body-weight, food consumption, no macroscopic findings. There 

were no cyprodinil-related effects on absolute, adjusted, or relative spleen or thymus weights; no 

effects on specific activity or total activity of splenic IgM antibody-forming cells to the T celldependent antigen sRBC. Effects did include higher mean absolute, relative to body weight, and 

adjusted liver weights noted in the 5000ppm cyprodinil-treated group were consistent with 

previous studies assessing cyprodinil at similar exposure levels. Noted for the positive control 

(CPS) were lower mean absolute and adjusted spleen and thymus weights when compared to 

vehicle control group. All effects seen with the CPS were consistent with the known 

immunosuppressant effects and also validated the appropriateness of the AFC assay. No 

mention of a NK cell activity assay was performed. It is unclear why this test was not performed 

and no justification was noted in the study write-up.

Based on the study, treatment of female Crl:CD-1(ICR) mice with cyprodinil given on a 

continued basis in the diet for 28 sequential days resulted in no apparent suppression of the 

humoral component of the immune system. The NOAEL for the suppression of the immune 

response in female CD-1 mice given cyprodinil was 5000ppm (1245.3mg/kg/day). The only 

effect attributed to cyprodinil treatment was higher mean absolute, relative to body weight, and 

adjusted liver weights also for the 5000ppm group. 
Page 44 of 46

APPENDIX B. Chemical Names And Structures Of Metabolites

B.1 Chemical Names and Structures

Table B.1 Cyprodinil and Metabolites Names and Structures

Chemical Name/Code Chemical Structure

Cyprodinil (CGA-219417)

4-cyclopropyl-6-methyl-N-phenyl-2-pyrimidinamine

N

N

CH3

N

H

CGA-232449

6-cyclopropyl-2-(phenylamino)-4-pyrimidinemethanol

CGA-304075

4-[(4-cyclopropyl-6-methyl-2-2-pyrimidinyl)amino]-

phenol

CGA-304076

N

N N

H

CH3

OH
Page 45 of 46

Table B.1 Cyprodinil and Metabolites Names and Structures

Chemical Name/Code Chemical Structure

NOA-413167

N

N N

H

OH

CH3

CGA-249287

4-cyclopropyl-6-methyl-2-pyrimidinamine

NOA-422054

4-cyclopropyl-6-hydroxymethyl-2-pyrimidinamine

N

N

OH

H2N

CGA-263208

phenylguanidine
Page 46 of 46

APPENDIX C. Physical/Chemical Properties

Table C.1 Physicochemical Properties of Technical Grade of Cyprodinil.

Parameter Value Reference

Melting point/range 75.9 0C

DP# 345970, W. Cutchin, 

6/4/08

pH 9.5 at 25 0C (1% aqueous dispersion)

Density 1.21 g/cm3at 200C

Water solubility (mg/L at 25 C) 16 at pH 7.6, 20 at pH 5, 13 at pH 7, 5 at 

pH 9

Solvent solubility (g/L at 25 C) ethanol-160, acetone-610, toluene-460,

n-octanol-160, n-hexane-30

Vapor pressure 3.8 x 10-6 mm Hg at 25 0C

Dissociation constant, pKa 4.44 at 20 0C

Octanol/water partition coefficient, 

Log(KOW) at 25 C

3.9 at pH 5, 4.0 at pH 7, 4.0 at pH 9

UV/visible absorption spectrum

(molar absorption coefficients for the 

absorbance maximum)

29,200 L/mol∙cm at 270.8 nm (neutral)

29,200 L/mol∙cm at 251.6 nm (acidic)

29,200 L/mol∙cm at 316.8 nm (acidic)

28,400 L/mol∙cm at 270.8 nm (basic)

APPENDIX D. Studies Reviewed for Ethical Conduct

The PHED Task Force, 1995. The Pesticide Handlers Exposure Database, Version 1.1. Task 

Force members Health Canada, U.S. Environmental Protection Agency, and the National 

Agricultural Chemicals Association, released February, 1995.

Agricultural Re-entry Task Force (ARTF) data base (SOP #3.1)