1

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

MEMORANDUM

DATE: October 6, 2015

SUBJECT: Estimated Drinking Water Concentrations of Cyazofamid and its Degradates of 

Concern CCIM, CCIM-AM and CTCA, for Use in Human Health Risk 

Assessment: Petitions for the Use on Herb (Subgroup 19A), Greenhouse Tomato,

Greenhouse Pepper, and Bulb Vegetables (Group 03-07)

(PC Code 085651; DP Barcode D426776)

TO: Laura Nollen, Chemical Review Manager

Barbara Madden, Minor Use Team Leader

Marion Johnson, Branch Chief

Risk Integration, Minor Use and Emergency Response Branch

Lindsay Roe, Chemical Review Manager

Tony Kish, Product Manager #22

Cynthia Giles-Parker, Branch Chief

Fungicide Branch

Registration Division (7505P)

AND: Cassi Walls, Risk Assessor

Charles Smith, Branch Chief

Registration Action Branch 1

Health Effects Division (7509P)

FROM: José Meléndez, Chemist

Environmental Risk Branch 5

Environmental Fate and Effects Division (7507P)

THROUGH: Mah T. Shamim, Ph.D., Branch Chief

Environmental Risk Branch 5

Environmental Fate and Effects Division (7507P)

This memorandum presents the Estimated Drinking Water Concentrations (EDWCs) for the 

fungicide cyazofamid, and for its major transformation products CCIM, CCIM-AM and CTCA, 

for use in the human health risk assessment. Requests for registration of several new crops were

submitted to the Agency, including Herb (Subgroup 19A), greenhouse tomato, greenhouse 
2

pepper, and use on Bulb Vegetables (Group 03-07). Based on a review of the use information, it 

was found that the proposed new crops have much lower seasonal application rates than 

previously assessed turf and ornamentals. The highest seasonal rates among the newly proposed 

crops belong to the Herb Subgroup 19A (which includes the previously evaluated specific crop 

basil) at ~0.7 lb a.i./A/ season, compared to 3.0 – 3.12 lb a.i./A/season for turf and ornamentals 

(Table 2). Surface water EDWCs for the new uses should be smaller than those already 

calculated for turf and ornamentals; the surface water values reported in the previous assessment 

can be used to cover the new crops. However, for groundwater, new EDWCs using the new

model PRZM-GW were calculated in the current Drinking Water Assessment (DWA)

(Appendix A).

The Health Effects Division (HED) Metabolism Assessment Review Committee (MARC) 

concluded that cyazofamid and the metabolites designated as CCIM, CCIM-AM and CTCA 

should be considered to be the major residues of concern in water and should be included in the 

drinking waters assessment (Acierto et al. 2004, DP Barcode D298915).1

As summarized in Table 1, the surface water acute EDWC is 38.2 ppb of cyazofamid plus 

the degradates CCIM and CCIM-AM (for further details, refer to the previous DWA). The 

surface water non-cancer chronic value is 133.5 ppb of CTCA and the cancer/chronic EDWC is 

77.3 ppb of CTCA. The above stated values represent upper-bound estimates of the parent and 

degradates’ concentrations that might be found in surface water due to the use of cyazofamid on 

turf and ornamentals, as reported previously in DP Barcodes D319466 and D356839. The 

maximum value for ground water is 224 ppb of CTCA for acute exposure and 211 ppb of CTCA 

for chronic exposure, resulting from the WI sand scenario (for further details, refer to the 

Appendix A). It should be noted that these are still screening-level values and further 

refinements may be conducted. Should any questions arise, please, contact EFED.

Table 1. Maximum Estimated Drinking Water Concentrations for Cyazofamid, CCIM, CCIM-AM 

and CTCA. Maximum EDWCs Are Based on the Use on Turf and Ornamentals

Drinking Water Source

(Model Used) Use (rate modeled per year)

Estimated Drinking Water Concentration (EDWC) (ppb) (Species)

Groundwater

(PRZM-GW)

Ornamentals (3.12 lb 

a.i./A/yr)

Acute (CTCA) 2241

Chronic (CTCA) 2111

Surface water

(PRZM/EXAMS)

Turf & Ornamentals

(3.0 & 3.12 lb a.i./A/yr, 

respectively)

Acute (cyazofamid, CCIM, CCIM-AM) 38.22

Chronic (CTCA) 133.52

Cancer/Chronic (CTCA) 77.32

1. For groundwater, acute and chronic exposure is based on modeling the degradate CTCA.

2. For surface water, acute exposure is based on modeling of the parent cyazofamid plus the degradates CCIM 

and CCIM-AM. Chronic exposure is based on modeling of the degradate CTCA.

For surface water, a previous DWA, dated March 24, 2009 (DP Barcode D356836), provides 

structures and nomenclature of cyazofamid and its transformation products. Moreover, a DWA 

dated September 6, 2006 (DP Barcode D319466), provides maximum surface waters 

(PRZM/EXAMS) EDWCs; in the 2006 assessment, turf and ornamentals were modeled. These 

previous DWAs provide specific information about the chemicals modeled (cyazofamid, CCIM,

CCIM-AM, and CTCA), structures, problem formulation and approach taken in modeling the 

 

1 Acierto, A., et al. Cyazofamid - Meeting Report of the Metabolism Assessment Review Committee (MARC), 

Health Effects Division Memo dated 02/18/2004; DP Barcode D298915.
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crops, a summary of physicochemical and environmental fate properties of the chemicals, etc. 

Additional details about the environmental fate database for cyazofamid can be found in the 

Problem Formulation for Registration Review of Cyazofamid (DP Barcode: D422930; March 16, 

2015). EFED calculated new groundwater EDWCs in the current DWA, which are provided in 

the Appendix A. At the present time, EFED did not evaluate the greenhouse uses of 

cyazofamid, since it is believed usage will be low; however, should additional greenhouse uses, 

besides tomatoes and peppers be added to the label, the Division may need to revisit the issue.

Use information:

There are two products that contain cyazofamid, both of which are flowable suspension

concentrates (SC): Ranman®400SC Fungicide label (EPA Reg. No. 71512-3) and Cyazofamid 

400SC Turf and Ornamentals (EPA Reg. No. 71512-13). The chemical is currently used on 

crops like potatoes, cucurbit vegetables, turf, ornamentals, carrots, fruiting vegetables & okra, 

and grapes (East of the Rocky Mountains) (Table 2). Requests for registration of new crops 

were submitted to the Agency, including Herb Subgroup 19A, greenhouse tomato, greenhouse 

pepper, and use on Bulb Vegetables Group 03-07. Based on a review of the use information, it 

was found that the proposed new crops have much lower seasonal application rates than turf and 

ornamentals. The maximum seasonal rates for the new crops range from 0.43 lb a.i./A/season 

for Bulb Vegetables Group 03-07, to ~0.7 lb a.i./A/season for Herb Subgroup 19A. In contrast, 

for turf and ornamentals, the seasonal application rates are much higher at 3.0 and 3.12 lb a.i./A, 

divided in 3 and 2 applications, respectively (Table 2).

Table 2. Summary of use information for cyazofamid, based on the current and proposed labels for 

RANMAN®400SC Fungicide label (EPA Reg. No. 71512-3), and label for Cyazofamid 400SC Turf 

and Ornamentals (EPA Reg. No. 71512-13). The new crops are shaded BLUE.

USE

SINGLE APP. 

RATE

(lb. a.i./A)

NUMBER 

OF 

APPLICS.

SEASONAL 

APP. RATE 

(lb. a.i./A)

INTERVAL 

BETWEEN 

APPS. (days)

APPLICATION 

METHOD

PHI

(days)

Bulb Vegetables, Crop Group 3-07 

(daylily, bulb; elegans hosta; fritillaria, bulb and 

leaves; garlic, bulb; garlic, great-headed, bulb; 

garlic, serpent, bulb; kurrat; lady's leek; leek; 

leek, wild; lily, bulb; onion, Beltsville bunching; 

onion, bulb; onion, Chinese, bulb; onion, fresh; 

onion, green; onion, macrostem; onion, pearl; 

onion, potato, bulb; onion, tree, tops; onion, 

Welsh, tops; shallot, bulb; shallot, fresh leaves; 

cultivars, varieties, and/or hybrids of these)

0.071-0.078 6 0.43 7

Foliar, sprinkler 

irrigation 0

Herb Group, Crop Subgroup 19A

(Basil1, angelica, balm, borage, burnet, 

chamomile, catnip, chervil (dried), chive, 

Chinese chive, clary, coriander leaf (Chinese 

parsley), costmary, cilantro (leaf), curry (leaf), 

dillweed, horehound, hyssop, lavender, 

lemongrass, lovage (leaf), marigold, marjoram 

(includes sweet and annual marjoram, wild 

marjoram or oregano, and pot marjoram), 

nasturtium, parsley (dried), pennyroyal, 

rosemary, rue, sage, summer and winter savory, 

sweet bay, tansy, tarragon, thyme, wintergreen, 

woodruff, and wormwood)

0.071-0.078 9 0.7 7

Foliar, sprinkler 

irrigation, can be 

applied on herbs

grown in greenhouses

0
4

USE

SINGLE APP. 

RATE

(lb. a.i./A)

NUMBER 

OF 

APPLICS.

SEASONAL 

APP. RATE 

(lb. a.i./A)

INTERVAL 

BETWEEN 

APPS. (days)

APPLICATION 

METHOD

PHI

(days)

Greenhouse Grown Bell Peppers

0.083 lb a.i./ 

100 gal water;

------

1

st app 5 fl oz 

solution/plant; 

2

nd app 8.5 fl 

oz solution/ 

plant

2

13.5 fl oz 

solution/ 

plant/crop 

cycle

42 Soil drench 0

Tomato Greenhouse Transplants

0.078 lb a.i./ 

100 gal water;

------

~1 pint 

solution/ft2

NS NS

As needed, 

starting from 

planting up 

until 1 week 

before 

transplanting

Soil drench 0

Fruiting Vegetables, Crop Group 8-10 

[tomato (field grown and greenhouse grown), 

ground cherry, tomatillo, bell pepper, cooking 

pepper, pimento, sweet pepper, eggplant, 

pepino, okra, African eggplant, bush tomato, 

cocona, currant tomato, garden huckleberry, goji 

berry, groundberry, martynia, naranjilla, pea

eggplant, non-bell pepper, roselle, scarlet 

eggplant, sunberry, tree tomato, cultivars, 

varieties and/or hybrids of these]

0.054-0.071 6 0.43 7

Foliar, to base of 

plant at transplanting 

or in transplant water, 

sprinkler irrigation; 

for tomatoes grown in 

greenhouses as 

drench application

0

Tuberous and Corm Vegetables, Crop 

Subgroup 1C (arracacha, arrowhoot, Chinese 

artichoke, Jerusalem artichoke, edible canna, 

bitter cassava, sweet cassava, chayote (root), 

chufa, casheen taro, ginger, leren, potato, tanier, 

turmeric, yam bean, true yam)

0.036-0.071 

(0.158 at 

planting; 0.071 

lay-by/ hilling)

10 0.71 7

Foliar, at plantingover the seed pieces, 

lay-by/ hilling

7

Leafy Greens, Crop Subgroup 4A 

[amaranth (leafy amaranth, Chinese spinach, 

tampala), arugula (Roquette), chervil, edible 

leaved chrysanthemum, corn salad, garden cress, 

upland cress (yellow rocket, winter cress), 

dandelion, dock (sorrel), endive (escarole), 

lettuce (head & leaf), orach, parsley, garden 

purslane, winter purslane, radicchio (red 

chicory), spinach, New Zealand spinach, vine 

spinach (Malabar spinach, Indian spinach)]

0.071 6 0.43 7

Foliar, to the soil 

(post-plant 

application) as a band 

over the seed band or 

transplant, in 

transplant water, 

sprinkler irrigation

0

Succulent-Podded & SucculentShelled Beans [Cicer arietinum (chickpea, 

garbanzo bean), Lupinus spp. (including sweet 

lupine, white sweet lupine, white lupine and 

grain lupine), Phaseolus spp. (including kidney 

bean, lima bean, mung bean, navy bean, pinto 

bean, snap bean, waxbean), Vacia fava (broad 

bean, fava bean), Vigna spp. (including 

asparagus bean, blackeyed bean, cowpea)]

0.071 6 0.43 7

Foliar, sprinkler 

irrigation 0

Grapes (East of the Rocky Mountains) 0.054-0.071 6 0.43 10 G or A 30
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USE

SINGLE APP. 

RATE

(lb. a.i./A)

NUMBER 

OF 

APPLICS.

SEASONAL 

APP. RATE 

(lb. a.i./A)

INTERVAL 

BETWEEN 

APPS. (days)

APPLICATION 

METHOD

PHI

(days)

Carrot 0.156 5 0.78 14

Pre-plant

incorporated or 

surface application 

(broadcast or band) or 

overhead irrigation 

system

14

Cucurbit Vegetables (Crop Group 9) 

[includes cantaloupe, chayote, Chinese 

waxgourd, citron melon, cucumbers, gherkin, 

gourds, honeydew melon, Momordica spp., 

muskmelon, watermelon, pumpkin, squash, 

zucchini]

0.054-0.071 6 0.43 7

G, A, in transplant 

water, sprinkler 

irrigation

0

Turf [such as golf courses (including greens, 

tees and fairways), sod farms, seed farms, 

college and professional sports fields, and 

commercial lawns]

0.5-1.0 3 3.0 14 G N/A

Ornamentals [including conifers, grown in 

containers in greenhouses, outdoor nurseries and 

landscapes]

1.56 2 3.12 14

G, soil drench, soil 

surface spray, 

irrigation systems

N/A

Hops 0.054-0.071 6 0.43 7 G, A 3

Brassica (Cole) Leafy Vegetables & 

Turnip Greens (Crop Group 5) [includes 

broccoli, Chinese broccoli (gai lon), broccoli 

raab (rapini), Brussels sprouts, cabbage, Chinese 

cabbage (bok choy), Chinese cabbage (napa), 

Chinese mustard (gai choy), cauliflower, cavalo 

broccolo, collards, kale, kohlrabi, mizuna, 

mustard greens, mustard spinach, rape greens, 

turnip greens]

Transplant soil 

drench 0.66;

soil 

incorporation 

0.52;

foliar 0.072

1 soil + 5 

foliar 1.02 7

G, A, transplant soil 

drench, soil 

incorporation, foliar, 

sprinkler irrigation

0

G=ground; A=aerial

1 Basil is a crop that was previously registered, but it belongs to the Crop Subgroup 19A.

Identification of specific data gaps:

After the submission of several new studies, it was found that the environmental fate 

database for cyazofamid is nearly complete. Additional details about the environmental fate 

database for cyazofamid can be found in the Problem Formulation for Registration Review of 

Cyazofamid (DP Barcode: D422930; March 16, 2015, and available at: 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2015-0128-0005). 

Environmental Chemistry Methods/Independent Laboratory Validations (OCSPP 850.6100), in 

soil, water and sediment, should be made available. It should be noted that the ECMs/ILVs’ 

results are not used to derive any of the input parameters for surface or ground water EDWCs.
6

Appendix A. Tier 1 EDWCs for Groundwater Using PRZM-GW

PRZM-GW v.1.07

Summary

The maximum value for ground water is 224 ppb of CTCA for acute exposure and 211 ppb

of CTCA for chronic exposure, associated with the Wisconsin sand scenario. There is a potential 

for these EDWCs to be higher, if the degradation of CTCA in the sandy soil is considered to be 

persistent in lieu of 365 days.

Conceptual Model

Figure A-1 depicts the general groundwater scenario concept for estimating pesticide 

concentrations in drinking water as implemented in PRZM-GW. This conceptual model is based 

on a rural drinking water well beneath an agricultural field (a high pesticide use area) drawing 

from an unconfined, high water-table aquifer.

Figure A-1. General Groundwater Scenario Concept for Estimating Pesticide 

Concentrations in Drinking Water as Implemented in PRZM-GW; The black line through 

the soil profile represents the decline in degradation with respect to the depth.

The depth of the well is site specific (i.e., scenario specific). The well extends into a shallow 

unconfined aquifer and has a well-screen2that starts at the top and extends down into the aquifer. 

The length of the well-screen represents the region of the aquifer where drinking water is 

collected. The well-screen length is well-specific and can be adjusted. Processes included in the 

conceptual model that influence pesticide transport through the soil profile include water flow, 

 

2 A well screen is a filtering device that allows groundwater from unconsolidated and semi-consolidated aquifers to 

enter the well while at the same time keeping the majority of sand and gravel out of the well.
7

chemical specific dissipation and transportation parameters (i.e., degradation and sorption), and 

crop specific factors, including transpiration, pesticide interception and management practices.

The following is a brief description of the PRZM-GW model. More information is available 

at http://www.epa.gov/oppefed1/models/water/ (accessed 06/25/2015).

Tier 1 groundwater estimated drinking water concentrations (EDWCs) for a 

chemical, resulting from its use on a crop are derived with PRZM-GW (Pesticide 

Root Zone Model for Groundwater, version 1.07, March 6, 2014), using the GWGUI (Graphical User Interface, version 1.07, March 6, 2014). PRZM-GW is a onedimensional, finite-difference model that estimates the concentrations of 

pesticides in groundwater. It accounts for pesticide fate in the crop root zone by 

simulating pesticide transport and degradation through the soil profile after a 

pesticide is applied to an agricultural field. PRZM-GW permits the assessment of 

multiple years of pesticide application (up to 100 years) on a single site. Six 

standard scenarios, each representing a different region known to be vulnerable to 

groundwater contaminations, are available for use with PRZM-GW for risk 

assessment purposes. In PRZM-GW simulations, each of these standard scenarios 

is used. PRZM-GW output values represent pesticide concentrations in a 

vulnerable groundwater supply that is located directly beneath a rural agricultural 

field.

Input Parameters for PRZM-GW and Results

Given that groundwater exposure occurs usually after a long period of time, the terminal 

degradate of cyazofamid was modeled in lieu of the parent cyazofamid. It was assumed 100% 

CTCA formation from the parent compound. The crop leading to maximum exposure is 

ornamentals, with an application rate of 1.56 lb a.i./A (2 applications allowed at 14-day

intervals). This corresponds to an application rate of 1.137 lb CTCA/acre. For input parameters 

used in this groundwater model, refer to Table A-1.

Table A-1. PRZM-GW Input Parameters for modeling ground applications of CTCA, a degradate 

of cyazofamid, on ornamentals

PARAMETER (units) VALUE1SOURCE COMMENT

Application date (day/month)

01-05

Label does not 

specify timing of 

applications. 

Applications are 

set to occur 

between crop 

emergence and 

harvest.

Delmarva emergence 10-04, crop maturation 30-

05, harvest 15-06

01-04 FL citrus crop emergence 01-01, crop maturation 

01-02, harvest 31-12

01-04 FL potatoes emergence 15-02, crop maturation 01-

05, harvest 01-06

01-06 GA coast emergence 01-05, crop maturation 01-

08, harvest 01-10

01-06 NC coast emergence 15-05, crop maturation 01-

08, harvest 01-11

01-06 WI sand emergence 01-05, crop maturation 21-07, 

harvest 20-10

Maximum Application Rate

(kg a.i./ha) 1.274 Label Maximum rate allowed is 1.56 lb a.i./A x 2 applications at 14 day interval. 100% conversion 
8

PARAMETER (units) VALUE1SOURCE COMMENT

Number of Applications per 

Year 2

of parent to CTCA is assumed. The molar 

conversion factor is 236.66/324.79 = 0.7287. 

Applying the conversion factor the maximum rate 

is 1.137 lb CTCA/A, or 1.274 kg CTCA/ha. Retreatment Intervals (days) 14

Chemical Application Method 

(CAM) 2 Label Foliar

Incorporation Depth (cm) 0 Label

Apply cyazofamid by ground equipment, soil 

drench, soil surface spray, or chemigation

applications to ornamentals.

Air diffusion coefficient 

(cm2/day)

0 N/A Assuming no volatilization.

Vaporization enthalpy 

(kcal/mol) 0 N/A Assuming no volatilization.

Henry’s Law Constant (atmm

3

/mol) 0 N/A Assuming no volatilization.

Partition Coefficient (KOC; 

mL/gOC)

836 45409114,

46537714

Sorption is correlated with organic carbon. Mean 

value out of four available soil values.

Aerobic Soil Metabolism 

Half-life (days)

288.2

45409105,

46537710

PestDF half-lives are as follows at 20°C:

208 days (SFO) in UK sandy loam, 359 days 

(SFO) in UK loamy sand, and 365 (SFO) in 

German sand.

90% upper confidence limits on the mean for the 

following corrected half-life values at 25°C: 147 

days (SFO), 254 days (SFO) & 258 (SFO), 

respectively. Mean = 219.67 days; standard 

deviation = 62.96 days; n = 3; t90, n-1 = 1.886.

Hydrolysis Half-life (days) 0

45409101,

46537702,

46702702

Stable at 50oC for 5 days in pHs 4, 7, and 9

buffered solutions.

1 Parameters are selected as per “Guidance for Selecting Input Parameters for Modeling Pesticide Concentrations in 

Groundwater Using the Pesticide Root Zone Model” v.1.0, dated October 15, 2012.

For three of the scenarios: FL potatoes, GA coast, and WI sand, extended weather files were 

required, since breakthrough was incomplete after 30 years. Results are provided in Table A-2.

Table A-2. Estimated Drinking Water Concentrations (EDWCs) of CTCA, a degradate of 

cyazofamid, resulting from the use on ornamentals

Crop/Scenario

Highest Daily 

Value

(μg/L)

Post Breakthrough 

Average

(μg/L)

Average Simulation 

Breakthrough Time

(days)

Ornamentals/Tier I Delmarva 44.9 44.6 10,913

Ornamentals/Tier I FL citrus 114 113 9,130

Ornamentals/Tier I FL potatoes 0.28 Incomplete Incomplete

Ornamentals/Tier I FL potatoes, 

with extended weather file 0.371 0.33 18,838

Ornamentals/Tier I GA coast 3.83 Incomplete Incomplete

Ornamentals/Tier I GA coast with 

extended weather file 31.1 28.9 15,032

Ornamentals/Tier I NC coast 62.1 60.7 9,688

Ornamentals/Tier I WI sand 51.9 Incomplete Incomplete

Ornamentals/Tier I WI sand with 

extended weather file 224 211 13,561

t t

t s

n

input

n

 



1 2

90 1

/

,

( )
9

Bolded values represent the maximum EDWCs.
10

Example Output File from PRZM-GW

Groundwater Analysis for CTCA and the Florida Citrus - FL Central Ridge, Polk 

County - (Tampa) Met File (12842.Dvf) - Astatula Sand, Hrgb A Scenario

Estimated groundwater concentrations and breakthrough times for CTCA are presented in 

Table 1 for the Florida Citrus - FL Central Ridge, Polk County - (Tampa) Met File (12842.dvf) -

Astatula sand, hrgb A groundwater scenario. A graphical presentation of the daily 

concentrations in the aquifer is presented in Figure 1. These values were generated with the 

PRZM-GW (Version 1.07). Critical input values for the model are summarized in Tables 2 and 3.

Table 1. Groundwater Results for CTCA and the Florida Citrus - FL Central Ridge, Polk County -

(Tampa) Met File (12842.dvf) - Astatula sand, hrgb A Scenario.

Peak Concentration (ppb) 114

Post-Breakthrough Mean 

Concentration (ppb)

 113

Entire Simulation Mean 

Concentration (ppb)

 53.1

Average Breakthrough 

Time (days)

9129.938

Throughputs 1.200446

Table 2. Chemical Properties for Groundwater Modeling of CTCA.

Koc (ml/g) 836

Surface Soil Half Life (days) 288.2

Hydrolysis Half Life (days) 0

Diffusion Coefficint Air (cm2/day) 0.0

Henry's Constant 0.0

Enthalpy (kcal/mol) 0.0

Table 3. Pesticide application scheme used for CTCA. This application scheme was applied 

every year of the simulation.

Application Date

(Month/Day)

Application Method Application Rate

(kg/ha)

04/01 Above canopy application 1.274

04/15 Above canopy application 1.274
11

Figure 1. Aquifer Breakthrough Curve for CTCA and the Florida Citrus - FL Central Ridge, Polk 

County - (Tampa) Met File (12842.Dvf) - Astatula Sand, Hrgb A Scenario