UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

OFFICE OF 

PREVENTION, PESTICIDES AND 

TOXIC SUBSTANCES

							

							PC Code No.:		085651

							DP Barcode:		D 356836

							Date:			March 24, 2009

MEMORANDUM				

	

SUBJECT:	Estimated Drinking Water Concentrations of Parent Cyazofamid
and its Degradates CCIM, CCIM-AM and CTCA for Use in Human Health Risk
Assessment (Use on Fruiting Vegetables, Crop Group 8 + Okra, and Grapes,
East of the Rocky Mountains).

TO:		Tony Kish, PM Team Reviewer

		Janet Whitehurst, Risk Manager Reviewer

		Cynthia Giles-Parker, Chief

		Fungicide Branch

		Registration Division (7505P)

AND:		Nancy Tsaur, Chemist

		Paula Deschamp, Chief

		Registration Action Branch III

		  SEQ CHAPTER \h \r 1 Health Effects Division (7509P)

FROM:	José L. Meléndez, Chemist

		Environmental Risk Branch V

		Environmental Fate and Effects Division (7507P)

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

		Environmental Risk Branch V

		Environmental Fate and Effects Division (7507P)

This memorandum presents the Estimated Drinking Water Concentrations
(EDWCs) for cyazofamid (CAS No. 120116-88-3), and for three of its major
transformation products CCIM, CCIM-AM and CTCA, for use in the human
health risk assessment (refer to appendix for the structures and
nomenclature of these chemicals).  The registrant seeks registration for
the new uses of the chemical on fruiting vegetables + okra, and grapes
(East of the Rocky Mountains).

Exposure to surface water is possible through surface water runoff, soil
erosion and/ or off-target spray drift.  The mobility of cyazofamid is
moderate (Kd range 5.14-43.31 mL/g; KOC range 815-1524 mL/gOC,
moderately to slightly mobile); however, cyazofamid is labile under many
conditions (e.g., in metabolism studies and under aqueous photolysis
conditions).  However, it degrades to a number degradates, which appear
to be persistent.  For cyazofamid and for its major transformation
products CCIM, CCIM-AM and CTCA (as per HED’s request), calculated
using tier 2 aquatic linked models PRZM/ EXAMS (surface water,
applications to turf and ornamentals) and the tier 1 aquatic model
SCI-GROW (groundwater, applications to ornamentals), EDWCs were
calculated.   As summarized in Table 1, the surface water acute EDWC is
38.2 ppb.  The surface water non-cancer chronic value is 133.5 ppb and
the cancer chronic EDWC is 77.3 ppb. The value for ground water is 2.18
ppb, which is suitable for both acute and chronic exposures.

The above stated values represent upper-bound estimates of the parent
and individual degradates’ concentrations that might be found in
surface water and groundwater due to the use of cyazofamid on turf and
ornamentals, as reported previously in DP Barcode 319466.   It is noted
that this is still a screening-level analysis.  A more refined
assessment could be performed. Should any questions arise, please,
contact José L. Meléndez at   HYPERLINK "mailto:melendez.jose@epa.gov"
 melendez.jose@epa.gov .

Identification of specific data gaps:

The environmental fate database consists of mostly supplemental studies.
 A degree of uncertainty exists in estimates of drinking waters
concentrations until new studies are submitted. 

EXECUTIVE SUMMARY 

Cyazofamid (CAS name: 
4-Chloro-2-cyano-N,N-dimethyl-5-(4-methylphenyl)-1H-imidazole-1-sulfonam
ide; IUPAC name:
4-chloro-2cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfonamide; CAS No.
120116-88-3: PC code 085651) is a cyanoimidazole selective fungicide. 
The pesticide’s mode of action is to target the fungi cytochrome bc1
(ubiquinone reductase) at Q1 site.  Cyazofamid is currently used on
potatoes, cucurbits, turf, tomatoes and carrots and it is proposed to be
used on fruiting vegetables + okra, and grapes (East of the Rocky
Mountains) through an IR-4 tolerance petition.

This memorandum is a drinking waters assessment (DWA) that presents the
EDWCs for parent cyazofamid, and the degradates CCIM, CCIM-AM and CTCA
for use in an FQPA human health risk assessment. Cyazofamid fungicide
and/or its degradates may reach both surface and groundwater under some
conditions.  The degradates’ EDWCs were modeled individually (as
opposed to the use of the total residue approach).  This was done
because sufficient data were available on the degradates to model them
individually (although some assumptions were made, see below).  It is
noted that DWAs were previously issued as follows:

Table 2.  Summary of Cyazofamid Drinking Water Exposure Assessments

Date	DP Barcode	Uses included

4/28/04	301099	Cucurbits, potatoes and tomatoes

9/6/06	319466	Turf and Ornamentals

3/5/08	342613	Carrots

This assessment	356839	Fruiting vegetables + okra, and grapes (East of
the Rocky mountains)



This DWA builds largely upon the previous assessments.  Additional runs
were performed to cover the new crops; the highest EDWCs of all crops
(past and present) were obtained for turf and ornamentals (surface
waters) and ornamentals (ground water).  The screening-level surface
water and ground water EDWCs were obtained using the tier 2 linked
aquatic models PRZM/ EXAMS and the tier 1 aquatic model SCI-GROW,
respectively.  EDWCs are summarized in Table 1 for three scenarios as
follows:

1st scenario: the parent is applied at the maximum rate;

2nd scenario: the degradates CCIM and CCIM-AM (and CTCA) are applied at
the parent-molar equivalent amounts, spreading the application rate
through the degradates, according to the molecular ratios and the
adjusted maximum percentages of the degradates observed in the
environmental fate studies; and

3rd scenario: the terminal degradate, CTCA, is applied assuming
application of 100% molar conversion of the parent to the degradate.

Based on the results presented in Table 1 below and a time-line of
exposure, the surface water acute EDWC is 38.2 ppb (equal to the Parent
“14.362 ppb” + CCIM “17.106 ppb” + CCIM-AM “6.699 ppb”). 
CTCA is not included in the surface water acute EDWC because it is not
expected to be present in this time frame. The surface water non-cancer
chronic is 133.5 ppb and the cancer chronic is 77.3 ppb (equal to the
value for the terminal degradate, CTCA). For ground water, the EDWC is
2.18 ppb, which is suitable for acute and chronic exposures (equal to
the value for the terminal degradate, CTCA).

Table 1. Maxima of surface and ground water EDWCs for cyazofamid and its
relevant major degradates.  Turf and ornamentals use pattern, previously
reported in D319466 (dated 9/6/06).

Scenario	Chemical	Surface water EDWCs (ppb)	Ground water EDWC (ppb)



Acute	Chronic “Non-Cancer”	Chronic “Cancer”

	1st  Scenario	Cyazofamid	14.362	0.377	0.279	0.01180

2nd  Scenario	CCIM	17.106	12.094	10.600	0.00061

	CCIM-AM	6.699	6.312	3.611	0.00270

3rd  Scenario 	CTCA	136.242	133.458	77.270	2.180

                           EDWCs	38.2	133.5	77.3	2.18



The above stated values represent upper-bound estimates of the parent,
individual degradates and/or terminal degradate concentrations that
might be found in surface water and groundwater due to the use of
cyazofamid on turf and ornamentals.  EFED emphasizes that this is a
screening level analysis, and should there be a need by HED, additional
refinements can be made.

The EDWCs for cyazofamid were determined based on laboratory and fate
data from mostly supplemental studies. EFED suspects the possible poor
extraction efficiency may have underestimated the half-lives of
cyazofamid, which could result in lower model values for EDWCs.  In this
respect, it is noted that major identified degradates (CCIM, CCIM-AM and
CTCA) may not constitute a significant part of the late accumulated
un-characterized bound residue (due to the apparent adequate extraction
of these degradates).  A degree of uncertainty exists in such estimates
until new studies with proven extraction procedures are submitted.

PROBLEM FORMULATION

This is a drinking water assessment that uses modeling and monitoring
data, if available, to estimate the ground water and surface water
concentrations of pesticides in drinking water source water
(pre-treatment) resulting from pesticide use on sites that are highly
vulnerable.

Background 

This assessment addresses exposure to parent cyazofamid and its
degradation products CCIM, CCIM-AM and CTCA.  As indicated above, three
DWAs have been conducted for cyazofamid.  Final EDWCs were presented for
the use on turf and ornamentals, which were covered in one of the
previous assessments.

In the DWA for turf and ornamentals, the highest acute EDWCs were
observed for the use on turf for the parent and CCIM, and ornamentals
for CCIM-AM.  The highest chronic EDWCs were observed for the use on
ornamentals.  The application rate for ornamentals was 1.56 lb a.i./A
(two applications), and for turf 1.02 lb a.i./A (three applications). 
It should be noted that there are no substantial changes in the DWA
methodology since the last assessment.  There are no new data in the
fate database.  Only the new crops were modeled.

Cyazofamid is characterized by a high molecular weight (324.79 g/mole),
has a relatively low solubility (0.107 ppm @ pH 7) and a low vapor
pressure and Henry’s Law Constant (<1.0 x10-7 mmHg, and <4.0x10-7
atm*m3/mole, respectively).  Therefore, cyazofamid is not expected to
partition substantially into the air from water or from dry or wet soil
surfaces. Available data suggest that cyazofamid has the potential to be
bio-concentrated by aquatic organisms such as fish (KO/W > 1000), but
EFED does not have a valid bio-accumulation in fish study at this time. 
Available environmental fate studies suggest that cyazofamid is not very
mobile, and that it quickly degrades into various products, depending on
the environmental conditions. Among the three major degradates for
cyazofamid (CCIM, CCIM-AM and CTCA), the two terminal degradates are
CCIM and CTCA.  CCIM is the major one in bodies of water with low
biological activity because it is the result of abiotic hydrolysis of
the parent.  CTCA is expected to be the major terminal degradate in
biologically active soils and in water/sediment systems.  Both CCIM and
CTCA are stable to abiotic hydrolysis and susceptible to leaching but
only CCIM is susceptible to biodegradation.  Cyazofamid could
potentially reach surface water via spray drift or runoff under certain
environmental conditions but the potential for it to reach ground water
is low. CCIM and CTCA could potentially be the terminal degradates in
surface water bodies affected by spray drift and/ or runoff depending on
the level of biological activity. However, only CTCA has a high
potential to contaminate groundwater due to its high persistence and
mobility.

Use Characterization

Cyazofamid is currently used on carrots, cucurbit vegetables, potatoes
and tomatoes.  In addition, it is used on turf and ornamental plants,
including container grown plants and field grown (bed) plants.

  SEQ CHAPTER \h \r 1 Table 2.  Summary of new use information for
cyazofamid, based on the proposed Ranman 400SC Fungicide label (EPA Reg.
No. 71512-3).

USE	SINGLE  APP. RATE             (lbs. a.i./A)	NUMBER OF APPS.	SEASONAL
APP. RATE (lbs. a.i./A)	INTERVAL BETWEEN APPS. (days)	APP. METHOD	PHI
(days)

Fruiting Vegetables (Crop Group 8) and Okra [includes tomato, ground
cherry, tomatillo, bell pepper, chili pepper, cooking pepper, pimento,
sweet peppers, eggplant and pepino]	0.054-0.0782	6 (@ 0.071)	0.426	7
Sprinkler Irrigation1	0

Grapes (East of the Rocky Mountains)	0.054-0.071	63	0.4263	10	G or A	30

1Includes center pivot, motorized lateral move, traveling gun, solid set
or portable (wheel move, side roll, end low, or hand move) irrigation
systems.

2The use at 0.078 lb a.i. is for greenhouse transplant production, for
control of Pythium spp.

3The registrant indicated that the maximum rate is 6x0.071 lb a.i./A or
0.426 lb a.i./A/season.



The label indicates that the product “may be applied with all types of
spray equipment normally used for ground and aerial applications.” 
The label further specifies that a maximum of three applications in a
series are allowed, and that they should be alternated with a fungicide
of different mode of action, to manage/ prevent resistance.  Aerial
applications to grapes are allowed.  The label does not have a
requirement of an established buffer strip to protect bodies of water.

For cucurbits vegetables, the label was amended.  The new label now
allows the use of cyazofamid for greenhouse transplant production at
0.078 lb a.i./A to control Pythium spp.  However, for cucurbits, the
most conservative scenario still is 6 applications at 0.071 lb a.i./A
(same one previously assessed).  In addition to the above mentioned
label, EFED evaluated the label amendment for Cyazofamid 400SC Turf and
Ornamentals Fungicide (EPA Reg. No. 71512-13) to include applications to
residential lawns by professionals.  The major change is the inclusion
of residential uses for turf.  There are no changes in the maximum
application rates for turf or ornamentals; therefore, these changes were
not assessed hereby.  Both products are flowable suspension concentrates
(SC).  Both products contain 34.5% active ingredient or 3.33 lb
a.i./gallon.

Based on the crops listed for cyazofamid, use is expected all throughout
the USA.  There is a single geographical label restriction on the use on
grapes, that it may be used only East of the Rocky Mountains
(consequently, it may not be used on the high use area on grapes in the
state of California).  At this time, there is no readily available
typical use or usage information for cyazofamid.

Conceptual Model 

The conceptual model is a written description and visual representation
of potential routes of off-site movement of the pesticide or degradates
of concern into surface or ground water that may be a source of drinking
water.  The conceptual model describes the approach that will be used in
the analysis phase and includes two components: the risk hypothesis and
the conceptual site model for surface and ground water.

For cyazofamid, the following drinking water hypothesis is being
employed for this assessment:

Cyazofamid use in accordance with the label, results in potential
contamination of surface water resources; it does not result in
contamination of ground waters because it is relatively labile. 
Degradates of concern of cyazofamid, CCIM, CCIM-AM and CTCA, result in
substantial contamination of surface and ground water resources because
they are formed in large quantities and/or persist.

The conceptual site model is a generic graphic depiction of the risk
hypothesis.  Through a preliminary iterative process of examining
available data, the conceptual model (i.e., the drinking water
hypothesis) is refined to reflect the likely exposure pathways that are
most relevant and applicable to this assessment (refer to the following
figure).

Cyazofamid is applied to the field (on numerous crops).  It appears that
crop uptake is unlikely or minimal because the KOC for the chemical is
moderately high (ranged from 657-2900).  In addition, the chemical shows
a relatively low solubility (0.107 ppm) and a high octanol/ water
partition coefficient (KOW = 1585).  Cyazofamid is not expected to move
substantially on/in the soils horizontally because it is not very
persistent.  On the other hand, spray drift is an important factor in
the contamination of nearby surface waters when cyazofamid is applied to
the field since it may be applied by aerial or ground methods.  Since
the field may be kept irrigated, large runoff events and events
accompanied with erosion may be a factor in horizontal movement for
cyazofamid’s degradates CCIM and CCIM-AM, resulting in acute exposure.
 Since cyazofamid is a labile compound, it may not be available for long
periods of time in the field; on the other hand, the degradate CTCA
appears to be more persistent.  CTCA is expected to be present in
surface waters on a chronic basis.  Vertical movement to subsurfaces is
expected to be an important component for CTCA, particularly after
repeated applications per year and year to year.  Volatilization is
expected to be a minor route of dissipation for the active ingredient
(Henry’s Law Constant <4.0x10-7 atm*m3/mol).

ANALYSIS

Fate and Transport Characterization: 

A summary of physicochemical properties of cyazofamid is shown in Table
3.  The chemical is a relatively insoluble compound in acidic, neutral
and alkaline conditions. The low vapor pressure and Henry’s Law
constant of cyazofamid suggest partitioning into the air from water
and/or dry or wet soil surfaces will not be an important route of its
dissipation in the environment. Cyazofamid has a KOW >1,000 suggesting
that it will potentially be bio-concentrated by aquatic organisms such
as fish. However, at this time, EFED does not have a valid
bioaccumulation in fish study. 

  SEQ CHAPTER \h \r 1 Table 3.  Nomenclature and physicochemical
properties of cyazofamid

Parameter	Value	MRID1

Chemical Classification	cyanoimidazole

Molecular Formula	C13H13ClN4O2S	

454090-38

Chemical Name (IUPAC)
4-chloro-2cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfonamide

	Chemical Name (CAS)
4-Chloro-2-cyano-N,N-dimethyl-5-(4-methylphenyl)-1H-imidazole-1-sulfonam
ide	Cyazofamid data sheet

CAS Number	120116-88-3	454090-38

Pesticide Classification	Fungicide

	Molecular Weight	324.79

	Physical State	Crystalline solid

	Water Solubility (ppm)	0.121 @ pH 5, 0.107 @ pH 7, 0.109 @ pH 9

	Vapor pressure (25oC)	<1.33 x10-5 Pa or <9.9810-8 mmHg or <1.32x10-10
atm.	EPA Fact sheet

Henry's Law Constant	<4.0x10-7 atm. m3 mole-1	Calculated

Octanol/Water Partition, KOW	1,585 (log KOW 3.2 @ 25°C)	454090-38

1 Study reference is an MRID number.



Cyazofamid and degradates fate and transport properties are based on
previously submitted studies and reports (EPA Risk Assessments dated
2004, 2006 and 2008).  Although, EFED requested additional studies, no
new studies have been submitted. Cyazofamid’s environmental fate data
are summarized in Table 4.

Table 4. Summary of environmental fate data for cyazofamid

Parameter	Value1	MRID

Hydrolysis	t½ ~ 11.9 days @ 25oC, pH 4

t½ ~12.9 days @ 25oC, pH 5	

t½ ~ 11.9 days @ 25oC, pH 7

t½ ~10.8 days @ 25oC, pH 9	

t½ ~ 13.4, 12.4, 11.2, 9.3 hrs @ 50 º C, pH’s 4, 5, 7, 9,
respectively	

Major degradates (of the recovered): CCIM (74-83%) and CCIM-AM (9-10%
only at pH 9)	

454090-39

465377-01

467027-01

Aqueous photolysis

at pH 5	t½ ~ 30 Minutes

Major degradates: CCTS (37.9% at 0.13 day), CCIM (39.6% at 0.25 and 2
days), HTID (18.5% at 21 days), and CDTS (9.6% at 36 days). The
degradate p-Toluamide (12.1% at 36 days) was identified only in the
[benzene-14C] cyazofamid.	

454091-02

465377-03

467027-03

Photolysis on soil	t½ ~ 47 days

Major degradates: None.

Minor degradates: CCIM (6%), CCBA (2%), CTCA (1%), and CCIM-AM (<1%). 
454091-03

465377-04

467027-04

Aerobic soil metabolism 2	t½ = 6.1-6.4 days in a loamy sand soil from
Ohio, Soil 1 (pH 6.5, %OC 0.66)

Major degradates: CCIM, CCIM-AM, and CTCA	454091-06

465377-05

	t½ = 3.7-4.0 days in a Sandy loam soil from England, Soil 2 (pH 7.6,
%OC= 1.2)

t½ = 4.3-4.4 days in a Sandy loam soil from  England, Soil 3 (pH 6.9,
%OC= 3.0)

t½ = 4.9-6.0 days in a Sandy soil from Germany, Soil 5 (pH 5.9, %OC=
0.63)

Major degradates: CCIM, CCIM-AM and CTCA	

454091-08

465377-06

Aerobic aquatic metabolism 2	t½ = 14.7- 18.0 days (total system): River
water/Sandy loam (~3:1) 

t½ =   9.5- 10.9 days (total system): Creek water/Sandy loam (~3:1)

Major degradates: CCIM (up to 47%), CTCA (up to 31%), and CCIM-AM (up to
11%)	454091-10

465377-12

467027-07

Anaerobic aquatic metabolism 2	 t½ = 5.6-6.2 Days (total system):
Milli-Q water/Sandy loam (~2:1) 

Major degradates (of the applied): CCIM (25%), CCIM-AM (17%); CTCA (22%)
454091-09

465377-11

467027-06

Adsorption/

Desorption 

(Kd and 

Koc in L Kg-1)	[Imidazole-4-14C]/[Benzene-U-14C]:

Loamy sand   (Ohio),  Soil 1: Kd =     9.99/  6.96 and Koc= 1,524/1,062

Sandy loam (UK),       Soil 2: Kd =   43.31/87.00 and Koc= 1,444/2,900

Sandy loam    (UK),    Soil 3: Kd =   14.11/13.49 and Koc= 1,176/1,124

Sand (Germany),         Soil 5: Kd =    5.14/ 4.14  and Koc=    815/  
657	

454091-12

465377-13

Mobility in Soils: Column Un-aged Leaching (4 soils)	> 98% of the
applied radioactivity remained on the top 10 cm with very limited
leaching. Observed rate and pattern of degradation were similar to
aerobic soil (Major degradates: CCIM, CCIM-AM). Leachate constituted
<0.3% of the applied radioactivity.	454091-13

465377-16

Mobility in Soils: Aged Leaching (one soil)	>95% of the radioactivity
remained on the top 10cm with very limited leaching. Observed rate and
pattern of degradation were similar to aerobic soil (Major degradates:
CCIM, CCIM-AM, and minor degradate CTCA). Leachate constituted nearly 1%
of the applied radioactivity and was dominated by the degradate CTCA
only. In comparison with unaged soils, radioactivity profile indicated
aging may have caused increased mobility	454091-11

465377-15

Accumulation in Fish	Invalid study	454091-38 454091-39 465377-24

1 Soil 1: Loamy Sand, Ohio (pH 6.5, %OC= 0.66); Soil 2: Sandy loam,
England (pH 7.6, %OC= 1.2); Soil 3: Sandy loam, England (pH 6.9, %OC=
3.0); Soil 4: Loamy sand, England (pH 7.6, %OC= 1.1); Soil 5: Sandy
soil, Germany (pH 5.9, %OC= 0.63).

2 Soil and aquatic systems range of half-lives are values for the two
labels. It is noted that longer half-lives were observed for the
aerobic/anaerobic aquatic systems in late intervals (a range of 19 to 30
days).



Available environmental fate studies suggest cyazofamid is not very
mobile and degrades relatively rapidly into various products, according
to the prevalent environmental conditions. Among the three major
degradates for cyazofamid, relevant to this assessment (CCIM, CCIM-AM
and CTCA), the two terminal degradates are CCIM and CTCA. Of them, CCIM
is a major hydrolysate.  It is expected to be the major terminal
degradate in bodies of water with low biological activity.  In contrast,
CTCA is expected to be the major terminal degradate in biologically
active soils and water/sediment systems.  Both CCIM and CTCA are stable
to abiotic hydrolysis and susceptible to leaching but only CCIM is
highly susceptible to biodegradation. Given these fate characteristics,
cyazofamid could potentially reach surface water via spray drift, or
runoff under certain environmental conditions, but the potential for it
to reach ground water is low. CCIM and/or CTCA could potentially be the
terminal degradates in surface water bodies affected by spray drift
and/or runoff depending on the level of biological activity.  However,
only CTCA has a high potential to contaminate groundwater due to its
high persistence and mobility.

Based on the referenced data, the main process involved in cyzofamid
fate in aqueous systems is direct photolysis followed by hydrolysis. Its
fate in the soil system appears to be controlled by biotic degradation
as well as its strong affinity for adsorption to the soil. Mobility of
cyazofamid in natural environments is expected to be limited because of
its strong affinity to adsorption. 

Available fate and transport data on cyazofamid major degradates CCIM,
CCIM-AM and CTCA, are presented in Table 5.

Table 5. Environmental fate data summary for the major and relevant
degradates of cyazofamid.





Parameter 1	Value (t½ for [phenyl-U-14C] - t½ for [imidazole-4-14C]
MRID ()

	CCIM	CCIM-AM	CTCA

	Hydrolysis	All three were relatively stable @ 50ºC for 5 days in pHs
4, 7, and 9.	454091-01

465377-02

467027-02



Aerobic soil metabolism 3

	Soil 3	 t½ = 1.92 - 1.3 days	t½ =  6.3 - 6.6 days 	

t½ >120 days (relatively stable) in all three soils 

	CCIM

454091-07

465377-07

465524-01

CCIM-AM

454091-04

465377-09

467027-05

CTCA

454091-05

465377-10

	Soil 4	t½ = 1.3 - 0.9 days	t½ =   10.0 - 6.6 days



	Soil 5	t½ =  2.9 - 2.6 days	t½ = 20.2 - 12.3 days



	Major degradates	CCIM-AM, CTCA, CCBA-AM.	 CTCA (max. 49.5-57.4% of the
applied)	None identified

	

Adsorption/ Desorption 

(Kd and Koc

in L Kg-1)

Using:

[Benzene-U-14C]	Soil 1	Kd= 3.91

Koc= 594	Kd= 22.43

Koc= 3,398	Kd= 8.96

Koc= 1,357	

454091-14

465377-14

	Soil 2	Kd= 5.70

Koc= 475	Kd= 23.30

Koc= 1,941	Kd= 9.80

Koc= 816



Soil 3	Kd=  23.57

Koc= 786 	Kd= 62.47

Koc= 2,082	Kd= 17.16

Koc= 572



Soil 5	Kd= 7.3

Koc= 1,158	Kd= 13.64

Koc= 2,165	Kd= 3.77

Koc= 599

	1 Soil 1: Loamy Sand, Ohio (pH 6.5, %OC= 0.66); Soil 2: Sandy loam,
England (pH 7.6, %OC= 1.2); Soil 3: Sandy loam, England (pH 6.9, %OC=
3.0); Soil 4: Loamy sand, England (pH 7.6, %OC= 1.1); and Soil 5: Sandy
soil, Germany (pH 5.9, %OC= 0.63).

 2 New submittals changed this value from 1.4 days to 1.9 days; this
slight change may not significantly impact the values used in modeling.

3 Range of half-lives are values for the two labels. It is noted that
longer half-lives were observed  at later in the experiments (a range of
2-7 days for CCIM and 14-28 days in the first two soils and >112 days
for the third soil for CCIM-AM.



Data on hydrolysis suggest that the three degradates are stable to this
abiotic process.  Various conclusions are derived from the data on
aerobic soil metabolism and mobility.  The first major degradate, CCIM,
appears to be susceptible to leaching but is short-lived.  CCIM-AM is
similar to its parent in its low persistence/mobility.  Finally, the
degradate CTCA appears to be susceptible to leaching with high
persistence. The major terminal-degradate in biologically active soil
and aquatic environments is expected to be CTCA because of the apparent
transformation of CCIM to CCIM-AM and finally into the persistent CTCA. 
Cyazofamid reaching surface water is expected to be highly affected by
hydrolysis, which transforms it into CCIM, which is stable to abiotic
hydrolysis.  Therefore, CCIM is expected to be the major terminal
degradate in bodies of surface water with low biological activity. 
Details on fate and transport studies including the transformation
profile are included in the three previously completed EFED chapters
(EPA 2004, 2006 and 2008). 

A summary of previously submitted field studies is shown in Table 6. 

Table 6. Summary of the terrestrial field dissipation study on
cyazofamid

Location (MRID)	Half-life1	Soil	Dissipation of Cyazofamid and its
Degradation Products

Grant County, WA

454091-16 (O)

465377-17 (R)

465524-02 (A)	t½ =  1.5 days 	Loamy sand

pH: 6.5

OM: 0.60%	Cyazofamid: was not detected below 0-15 cm.

Degradation Products: CCIM-AM and CTCA (detected through 540 days).

CTCA was detected 8 times in the 15-30 cm soil layer throughout the
540-day experiment.

Wayne County, NY

454091-17 (O)

465377-20 (R)

465524-03 (A)	t½ =8.5 days	Sandy loam

pH: 6.1

OM: 3.33%	Cyazofamid: was not detected below 0-15 cm.

Degradation Products: CCIM-AM (detected through 28 days), and CCBA
(detected sporadically at 0.03-0.01 ppm); CCIM and CTCA detected at
0.01-0.02 ppm through the 540-day study.

Degradates were not generally detected below 0-15 cm with the exception
of CTCA which was sporadically detected in the 15-30 cm layer. 

Montezuma, GA

456385-12 (O)

465377-23 (R)

467842-01 (A)	t½ =  2.0 days	Loam

pH: 6.2

OM: 0.55%	Cyazofamid: was not detected below 15 cm.

Degradation Products: CCIM, CCIM-AM and CTCA (detected through 540
days).

Only CCIM-AM was sporadically detected in the 15-30 cm layer.

Watsonville, CA

456385-13 (O)

465377-22 (R)

467842-02 (A)	t½ = 15 days 	loam

pH: 6.5

OM: 2.38%	Cyazofamid: was detected only once below 15 cm.

Degradation Products: CCIM-AM and CTCA were detected through 582 days
with maximum concentrations reaching  >10%, CCBA (detected through 582
days), and CTCA detected at the end of the study period.

Degradates were not detected below 0-15 cm, except of CCIM-AM which was
sporadically detected.

Pikeville, NC

465871-01	t½ days:

Grass:             7

Thatch:   29-32 

Soil:       15-120	Sandy loam

pH: 5.7

OM: 2.2%	Cyazofamid: was detected only once in the 7.5-15 cm soil layer.

Degradation Products: CCIM, CTCA, CCIM-AM, and CCBA were all detected in
minor amounts (<10%) in the three layers while only CCIM-AM was detected
at >10% of the total applied parent in the thatch layer only.

Ashland, VA

465711-02	t½ days:

Grass:             3

Thatch:   09-26 

Soil:        10-25	Sandy loam

pH: 6.8

OM: 1.1%	Cyazofamid: was detected only once in the 7.5-15 cm soil layer.

Degradation Products: CCIM, CTCA, CCIM-AM, and CCBA were all detected in
minor amounts in grass and thatch layers while only CTCA was detected in
minor amounts in the soil layer.

1 t½ = first order half-life; DT50= Dissipation time of 50% of the
compound.



The major uncertainties in the environmental fate database are related
to the fact that the half-lives were obtained from supplemental aerobic
soil, and aerobic and anaerobic aquatic metabolism studies. It is
suspected that poor extraction may have caused an underestimation of the
half-lives of cyazofamid and degradates. On the other hand, the major
identified degradates (CCIM, CCIM-AM and CTCA) may not be a significant
portion of the late accumulated un-characterized bound residues.  The
extraction of these degradates appeared to be adequate; however, a
degree of uncertainty exists in the half-life estimates until new
studies are submitted with proven extraction procedures.  No data were
submitted by the registrant to suggest that reasonable attempts were
made to extract or analyze significant soil or sediment bound
radioactivity.

Drinking Water Exposure Modeling

In order to model the new crops, representative scenarios were chosen: 
CA tomato, FL peppers and PA tomato, to represent fruiting vegetables
and okra; and NY grapes, to represent grapes - East of the Rocky
Mountains.  The maximum application rate allowed by the label was
utilized.

Model Selection:

Models

SCI-GROW (Screening Concentration in Ground Water v.2.3) (SG23.exe, July
29, 2003) is a regression model used as a screening tool to estimate
pesticide concentrations found in ground water used as drinking water. 
SCI-GROW was developed by fitting a linear model to groundwater
concentrations with the Relative Index of Leaching Potential (RILP) as
the independent variable.  Groundwater concentrations were taken from
90-day average high concentrations from Prospective Ground Water
studies; the RILP is a function of aerobic soil metabolism and the
soil-water partition coefficient.  The output of SCI-GROW represents the
concentrations that might be expected in shallow unconfined aquifers
under sandy soils, which is representative of the ground water most
vulnerable to pesticide contamination likely to serve as a drinking
water source. (Ref. 8).

For agricultural uses, exposure concentrations for surface drinking
waters assessments were estimated based on EFED’s Tier 2 aquatic model
PRZM/ EXAMS.  A graphical user interface (PE5 v. 5.0, November 15,
2006), developed by the EPA <  HYPERLINK
"(http://www.epa.gov/oppefed1/models/water" 
http://www.epa.gov/oppefed1/models/water >, was used to facilitate
inputting chemical and use specific parameters into the appropriate PRZM
input files (inp) and EXAMS chemical files.  The Pesticide Root Zone
Model (PRZM v. 3.12.2, May 12, 2005) field or orchard crop scenario is
the basic file which describes the local or regional climatological
information, soil hydrology, soil characteristics, crop characteristics,
and the pesticide properties necessary to determine pesticide loadings
to surface (or ground) water.  This basic file constitutes the first
part of the “exposure scenario.”  It simulates the processes in the
agricultural field, such as runoff and erosion, on a daily time step. 
The runoff and erosion flux output data from PRZM are used as chemical
loadings to the Exposure Analysis Modeling System (EXAMS v. 2.98.04.06,
April 25, 2005), which simulates surface water, in order to predict the
EDWCs.  EDWCs were determined using a reservoir scenario which describes
a vulnerable surface drinking waters scenario for the EXAMS component of
the modeling exercise.

Scenario Selection.

As indicated earlier, representative scenarios were chosen.  The crop
scenarios, selected to represent fruiting vegetables and okra, were CA
tomatoes, FL peppers and PA tomatoes (selected to represent different
regions of the USA).  The crop scenario chosen to represent grapes -
East of the Rocky Mountains, is NY grapes (this is the single standard
grape scenario available in the East of the USA).  The application dates
were selected according to the met file, to represent typical use of a
fungicide on the crops listed above.

Approach to calculation of EDWCs for cyazofamid and its degradates

Cyazofamid is a relatively new fungicide and no surface water monitoring
data are available.  For this reason, the Agency based this report on
simulated screening values using modeling.  The screening level surface
water and ground water estimates are calculated using tier 2 linked
PRZM/EXAMS models and the tier 1 SCI-GROW model, respectively.  It is
noted that: 

EDWCs for cyazofamid and its degradates were generated from the models
in which the KOC and aerobic soil half-life values used were obtained
from supplemental studies; 

Solubility of the degradates were considered to be the same as parent
(0.107 ppm); 

Direct photolysis half-life for the degradate CCIM was estimated from
its formation and decline curve in the aqueous photolysis study
conducted on the parent (a half-life of 31.52 days); 

The degradates CCIM-AM and CTCA were considered to be stable to direct
photolysis in water as they were not identified in the parent aqueous
photolysis study, and therefore, half-lives could not be calculated; and


The initial residue levels for degradates used in the models were based
on molecular ratios; assuming time zero 100% conversion of parent to a
mixture of degradates based on weight adjusted maximums in fate studies.
 EFED believes that this assumption is reasonable and conservative. The
calculated initial residue levels are presented in Table 7.

Table 7. Calculated application rates used in modeling of scenarios 1
(parent only), 2 (mix of degradates), and 3 (CTCA only, terminal
degradate)

Chemical	Molecular Weight *	Molecular Ratio	Determined Maximum (% Parent
Equivalent)	Application Rate**

(lb a.i./A)



	Value	Adjusted Value	Fate Study Used	Fruit. Veg.	Grapes

Parent	324.79	1	100%	100%	Assumed	0.071	0.071

CCIM	217.66	0.6702	83%	63%	Hydrolysis	0.0300	0.0300

CCIM-AM	235.67	0.7256	17%	13%	Anaerobic Aquatic	0.00670	0.00670

CTCA	236.66	0.7287	31%	24%	Aerobic Aquatic	0.0124	0.0124

Total	131%	100%

CTCA	236.66	0.7287	100%	100%	Assumed	0.0517	0.0517

* Molecular weights for degradates of cyazofamid were calculated by
deduction/ addition of elements, when compared to the parent structure.

** Rate for each degradate = Parent Rate x Molecular Ratio x adjusted
maximum found in fate studies; for example the rate for CCIM application
on fruiting vegetables = 0.071 x 0.6702 x 63% = 0.0300 lb a.i/A.



Based on the procedure outlined above, the application rates (in kg
a.i./A, the units used in PRZM/ EXAMS) used for the different runs are
included, along with other modeling parameters, in Table 8.  

Table 8. Modeling parameters for cyazofamid and degradates



Scenario	Modeled Chemical	Max. Single Rate (kg a.i./ha)*	Other
parameters



Fruit. Veg.	Grapes	Fruiting Vegetables

Number of applications:  6

Minimum interval: 7-day**

Scenario (application date): CA (11-03) and PA tomato (26-04); FL pepper
(11-09)

Application Efficiency: 0.99

Drift: 0.01

Intervals: 7, 7, 21, 7, 7 days

	Grapes

Number of applications: 6

Minimum interval: 10-day**

Scenario (application date): NY grape (05-05)

Application Efficiency: 0.95

Drift: 0.05

Intervals: 10, 10, 30, 10, 10 days

First	Parent	0.0796	0.0796



Second	CCIM	0.0336	0.0336



	CCIM-AM	0.0075	0.0075



	CTCA	0.0139	0.0139



Third	CTCA	0.0579	0.0579



* By multiplying label rates in lb/A by the conversion factor 1.1208;
for example for fruiting vegetables, parent:  Application Rate = 0.071 x
1.1208 = 0.0796 kg/ha.

**The label instructs not to make more than two or three consecutive
applications of the product; instead, follow with at least two or three
applications of a fungicide with a different mode of action.  Intervals
are as indicated.



Fate and transport input parameters are summarized in Table 9.

  SEQ CHAPTER \h \r 1  Table 9.  PRZM/EXAMS input parameters for
modeling surface water’s EDWCs of cyazofamid

Input Parameter	Chemical	Value1	Reference

Molecular Weight (gram mole -1)	Parent	324.79	MRID 454090-38

	CCIM	217.66



CCIM-AM	235.67



CTCA	236.66

	Vapor Pressure (mmHg)	All	1.0x10-7	EPA Factsheet

Henry’s Law Constant (atm-m3 mole-1)	All	4.0x10-7	Calculated

Aerobic Soil Metabolism Half-life (days)	Parent	5.5	The 90th percentile
t½ from eight values for the parent and six values for each degradate
(MRIDs 454091 06/08/07/04/05).

	CCIM	2.22



CCIM-AM	13.58



CTCA	Stable

	Water column Half-life (days)

(Aerobic Aquatic Metabolism half-life)	Parent	16.4	The 90th percentile
t½ from four values for the parent (MRID 454091-10).  For the
degradates, twice the aerobic soil metabolism input since the degradates
are stable to hydrolysis, as per guidance  (US EPA, 2002)

	CCIM	4.44



CCIM-AM	27.16



CTCA	Stable

	Benthic sediment Half-life (days) 

(Anaerobic Aquatic Metabolism half-life)	Parent	17.7	One half-life
value; 3x5.9=17.7 (MRID 454091-09)

	Degradates	Stable	No anaerobic aquatic metabolism data

Application Rate (Kg a.i./ha)	     All; Refer to Table 8

Application Number (Method of application)	All; Refer to Table 8	Product
Label

Application Interval	All; Refer to Table 8	Product Label

IPSCND (disposition of pesticide remaining on foliage after harvest)	All
1	Pesticide remaining on foliage is converted to surface application to
the top soil layer

UPTKF = PLVKRT = PLDKRT	All	0	As per Guidance for Selecting Input
Parameters.1

FEXTRC	All	0.5	As per Guidance for Selecting Input Parameters.1

Depth of Incorporation (cm)	Parent	0.0	CAM=2/ linear foliar based on
crop canopy (label); parent is applied by ground or aerial methods

	Degradates	5.08	CAM=4/soil application (Product Label); degradate is
expected to form, from parent in the top soil

Spray Drift (fraction)	Parent and Degradates	0.064 for fruiting
vegetables and 0.16 for grapes; degradates are expected to form in the
surface water

Application Efficiency (fraction)	Parent and Degradates	0.99 for
fruiting vegetables and 0.95 for grapes

Solubility (ppm)	Parent and Degradates	1.07	10X the solubility as per
guidance MRID 454090-38

KOC (L Kg-1)	Parent	1,338	Parent: Average of eight values (MRID
454091-12). 

Degradates: Average of four values for each of degradates (MRID
454091-14). 

KOC model was determined to be appropriate.

	CCIM	753



CCIM-AM	2,397



CTCA	836

	Hydrolysis Half-life @ pH 7 (days)	Parent	11.9	Maximum value at pH 7
(MRID 454090-39) 

	Degradates	Stable	MRID 454091-01



Aqueous Photolysis Half-life (days)	Parent	0.02	Maximum dark control
corrected value (MRID 454091-02)

	CCIM	31.5



Other degradates	Stable	No data

1 Parameters are selected as per Guidance for Selecting Input Parameters
in Modeling the Environmental Fate and Transport of Pesticides; Version
II, February 28, 2002.



Results of PRZM/EXAMS modeling are summarized in Table 10, noting that
an 87% was used for Percent Crop Area (PCA).  The value of 87% is the
national default for all other crops. 

Table 10. PRZM/EXAMS results of this assessment (EDWCs in ppb)

Crop/Scenario	PCA (%)	Chemical	Peak	Yearly	All Years

CA Tomato	1st	87%	Parent	0.568	0.0184	0.0137

	2nd 	87%	CCIM	0.183	0.0171	0.0144



87%	CCIM-AM	0.0689	0.0172	0.0148

	3rd	87%	CTCA	1.90	1.35	1.16

FL pepper	1st	87%	Parent	3.50	0.0662	0.0407

	2nd 	87%	CCIM	0.541	0.0180	0.0122



87%	CCIM-AM	0.191	0.0227	0.0166

	3rd	87%	CTCA	7.93	1.37	0.992

PA tomato	1st	87%	Parent	1.04	0.0501	0.0245

	2nd 	87%	CCIM	0.189	0.0164	0.0130



87%	CCIM-AM	0.117	0.0318	0.0211

	3rd	87%	CTCA	3.80	1.95	1.49

NY grape	1st	87%	Parent	1.32	0.0552	0.0442

	2nd 	87%	CCIM	0.326	0.0385	0.0325



87%	CCIM-AM	0.177	0.0703	0.0585

	3rd	87%	CTCA	4.81	3.41	2.67

Maxima	*Parent + CCIM + CCIM-AM 	4.23*



	**CTCA only

3.41**	2.67**



For ground water, SCI-GROW program, a high exposure tier one model, was
used to arrive at the Estimated Drinking Water Concentration (EDWC) for
this chemical and its degradates from ground water sources.  Modeling
input and output values are summarized in Tables 11 and 12, noting that
the rates are the ones for the highest exposure (ornamentals).  In
addition, scenarios 1 and 2 are for information only, since the parent
and the degradates CCIM and CCIM-AM are not likely to be observed in
ground waters.

Table 11. Input data for SCI-GROW modeling for EDWCs from ground water
for cyazofamid/ degradates

Parameter	Value*	Reference (MRID Number)

Crop/ Seasonal No. of Applications	Soil Applied to Ornamentals/2	High
Exposure (maximum rate/number); Product label



Label Application Rate (lb a.i./acre)	1st Scenario: Parent	1.56	Product
label (lb a.i/A)

	2nd Scenario: CCIM	0.659	

Calculated from molar ratios (refer to Table 8, above for a sample
calculation (lb a.i/A)

	CCIM-AM	0.147



3rd Scenario: CTCA	1.137

	Aerobic Soil Metabolism t½ (days)	Cyazofamid	4.7	Median of 8 values
(454091-06/08)

	CCIM	1.4	Median of 6 values (454091-07)

	CCIM-AM	8.3	Median of 6 values (454091-04)

	CTCA	10,000	Considered stable; half-life is >120 days (454091-05)

Koc (L Kg-1)	Cyazofamid	657	Lowest value (454091-12); variations >3 fold

	CCIM	690	

Median of 4 values for each degradate (454091-14)

	CCIM-AM	2,124



CTCA	708

	* Fate data values are chosen as per Guidance for Selecting Input
Parameters in Modeling the Environmental Fate and Transport of
Pesticides; Version II February 28, 2002.



Table 12. Summary of outputs from SCI-GROW modeling for EDWCs from
ground water for cyazofamid.

                              Parameter	Value/ ppb	Source

Screening EDWC for ground water			1st Scenario: Parent	0.0118	Output
from SCI-GROW model runs

	2nd Scenario: CCIM	0.000607



              CCIM-AM	0.00275



3rd Scenario: CTCA	2.18

	

It is important to note that modeling for EDWCs from surface and ground
water is performed using maximum application rate and frequency, and
minimum intervals, which allows establishing first level values suitable
for screening purposes. They may be referred to as likely upper bound
values due to the use of the chemical at the maximum application rate
and additional refinements can be developed should they be needed. 

Monitoring Data

Monitoring data provide different kinds of information than modeling
estimates.  For example, monitoring data consist of actual information
from the field, reflecting current use pattern and usually
underestimating frequency of occurrence.  Monitoring data does not
always include peak values, and inputs for monitoring cannot be adjusted
as modeled ones can.  In addition, monitoring is often conducted for
purposes other than characterizing exposure from a particular pesticide,
and as a consequence is used to complement modeling rather than to
refine it.  In general, a useful interpretation of monitoring values
requires in-depth assessment of the data, which is beyond the scope of a
Tier I assessment.

Cyazofamid is a relatively new fungicide and no surface water monitoring
data is available.

Drinking Water Treatment

There are no data available related to drinking water treatment of
cyazofamid and its degradates.

EXPOSURE CHARACTERIZATION 

A drinking waters assessment was performed for cyazofamid and EDWCs were
obtained for the parent and degradates CCIM, CCIM-AM and CTCA.  These
degradates were modeled as per request of HED.  They were present at
high concentrations, were persistent and/ or were judged to have a high
degree of toxicity.  Preliminarily, HED needs are point estimates (as
opposed to distributions).

Four standard crop scenarios were utilized to represent fruiting
vegetables and grapes (East of the Rocky Mountains).  Fruiting
vegetables were represented by CA tomato, FL pepper and PA tomato. 
These scenarios are located in a variety of sites in the nation and
could be considered representative of the proposed use areas. 
Furthermore, based on the crops represented1, the tomato and pepper
crops are appropriate crop scenarios.  Grapes were represented by the
standard scenario NY grape.  This is the only grape scenario available
in the East of the nation.  Additional scenarios not considered in this
assessment include: FL tomato (not used because another FL scenario was
utilized); CA grape and CA wine grape RLF (these scenarios are not
located in the intended use sites, also the CA wine grape scenario was
developed for red legged frog endangered species assessments); and PA
vegetable NMC and S TX vegetable NMC (these are regional scenarios).

For fruiting vegetables and grapes, the labeled range of application
rates is 0.054 to 0.071 lb a.i./A per application.  In addition,
fruiting vegetables for greenhouse transplant production may receive
applications at 0.078 lb a.i./A when used against Pythium spp.  The
maximum application rate of 0.071 lb a.i./A (for outdoor applications)
was used in all instances.  For resistance management, not more than 6
sprays of the product are allowed for both fruiting vegetables and
grapes.  Also, not more than 3 consecutive applications of cyazofamid
are allowed, and at least 3 applications of other fungicides with
different mode of action should be alternated.  The interval between
applications is 7-10 days for fruiting vegetables, and 10-14 days for
grapes.  The minimum interval between applications was used in all
instances.  It is unknown if the maximum application rate with the
minimum interval between applications would be typically used.  The
label instructs to use the lowest rate with the longest intervals for
preventative applications or for very low disease pressure.  There are
no usage data readily available that would indicate the percent crop
area treated (PCA) for the new crops.  The national default of 87% (used
for all “other crops”) was assumed for all runs, all of which adds
conservativeness to the assessment.  A regional restriction for grapes
is the use on the East of the Rocky Mountains.

EDWCs for cyazofamid and degradates were calculated for drinking water
based on half-lives obtained from supplemental aerobic soil and
aerobic/anaerobic water/sediment metabolism studies.  In these studies,
suspected poor extraction may have underestimated the half-lives of
cyazofamid and degradates possibly resulting in lower model values for
the EDWCs.  In this respect, it is noted that major identified
degradates (CCIM, CCIM-AM and CTCA) may not constitute a significant
part of the late accumulated un-characterized bound residue (due to the
apparent adequate extraction of these degradates); however, a degree of
uncertainty exists in such estimates until new studies with proven
extraction procedures are submitted. No data were submitted by the
registrant to suggest that reasonable attempts were made to extract or
analyze significant soil or sediment bound radioactivity. Complete
characterization of the fate of cyazofamid requires data to prove that
no parent or degradates were left as part of the bound residue and to
characterize various other components that may be present.  As a result,
EFED is requiring additional fate information/data be submitted to
assess the impact of these residues on the environment.

For SCI-GROW, a complete input dataset was available from submitted
studies, but the aerobic soil metabolism half-lives were from
supplemental studies.  For CTCA, an aerobic soil metabolism half-life of
10,000 days (>27 years) was assumed, since no degradation occurred in
the available study (MRID 45409105; three soils, two radiolabels).

In this assessment the total residue method (or approach) was not used. 
Each metabolite of concern was modeled separately.  The structures of
all three relevant degradates are the result of the loss of the
sulfonamide moiety.  The fate behavior and other characteristics of the
degradates may not resemble the ones for the parent.  There is
uncertainty in the input parameters for the degradates since no aquatic
metabolism (aerobic or anaerobic), solubility, vapor pressure and
Henry’s Law Constant were available.  Certain assumptions were made. 
For the parent and for all the degradates (CCIM, CCIM-AM and CTCA), in
PRZM/ EXAMS, the vapor pressure, Henry’s Law Constant and solubility
were assumed to be the same.

There were 8 half-lives for aerobic soil metabolism of the parent, and 6
for each of the degradates.  The upperbound value (90th percentile) was
used in each case as input for PRZM, as indicated by the input parameter
guidance.  The fact that there were multiple aerobic soil half-lives
reduces the uncertainty in this input parameter considerably. 
Nevertheless, with respect to the aerobic aquatic metabolism input for
EXAMS, there were no studies for the degradates, and 2x the aerobic soil
metabolism input was used, as per guidance.  It was noted that for the
parent, based on laboratory data, the aerobic aquatic metabolism input
value (16.4 days) is roughly 3x the aerobic soil metabolism input value
(5.5 days).  In the case of the anaerobic aquatic metabolism input,
there was only one half-life for the parent, and it was multiplied by a
3x factor to get the input used in the model.  The 3x factor is used to
account for the uncertainty surrounding the fact that only one half-life
was available.  For the degradates there was no data, and they were
assumed stable to anaerobic aquatic metabolism.  The impact of this
assumption is to overestimate the EDWCs if the chemicals are not in fact
persistent in anaerobic media.

The depth of incorporation selected for the parent, cyazofamid, was 0.0
cm (appropriate for spray or foliar aerial or ground applications).  For
the degradates, it was assumed to be 5.08 cm (2 inches) to mimic the
formation of the degradates on the top soil layer.  For the degradates,
a spray drift value of 6.4% or 16% was utilized (for ground or aerial
applications, respectively).  The drift was modeled this way because the
degradates may be formed in surface waters.  For both the parent and all
the degradates, the KOC model was determined to be appropriate (as
opposed to the Kd model).  Individual mobility data were available for
all the degradates.  The aqueous photolysis half-life for the parent
cyazofamid is very short (0.02 days or around 30 min).  Aqueous
photolysis is expected to occur more often in clear shallow waters,
where the sunlight is able to penetrate; the process is expected to
result in the formation of various degradates.  Based on its decline in
the parent aqueous photolysis study, a half-life of 31.5 days was
derived for CCIM and utilized in modeling.  For the aqueous photolysis,
the input parameter guidance does not stipulate the use of a factor
(e.g. 3x) in any case; there may be uncertainty regarding the use of
such a short half-life.

Environmental fate data reported in the TOXNET (HSDB) database is
generally consistent with the data available directly to the Agency; no
other sources of fate data were identified (e.g. an EU DAR or a PMRA
regulatory note).

Of the three fruiting vegetables crop scenarios tested, CA tomato, FL
pepper and PA tomato, the FL pepper scenario yielded the highest peak
EDWC (refer to Table 10), while the PA tomato yielded the highest
chronic EDWCs (though lower than for NY grapes).  For the uses on turf
and ornamentals, the surface water acute EDWC is 38.2 ppb.  The surface
water non-cancer chronic value is 133.5 ppb and the cancer chronic EDWC
is 77.3 ppb (Table 1).  By comparison, the EDWCs for the uses on
fruiting vegetables and grapes were as follows: peak 4.23 ppb;
non-cancer chronic 3.41 ppb; and cancer chronic 2.67 ppb.  These EDWCs
correspond to 11.1%, 2.55% and 3.45% of the corresponding values for the
uses on turf and ornamentals, respectively.

In this memorandum, the acute EDWCs were obtained from the sum of values
of three runs: for the parent, for CCIM, and for CCIM-AM. This means
that resultant EDWCs may have been overestimated and are expected to be
conservative because of nearly double counting the application rate
(full rate for the parent + estimated rates for CCIM and CCIM-AM). On
the other hand, chronic values were obtained from EDWCs for the terminal
degradate, CTCA, which was considered persistent to all fate processes,
which is unlikely (CTCA would be dissipated only by binding and
dilution).  In addition, 100% conversion of the parent to the degradate
was assumed (also unlikely).  Therefore, the resultant chronic EDWCs are
also expected to be highly conservative.

Degradates CCTS, HTID, CDTS and p-Toluamide were found as major
degradates only in aqueous photolysis studies.  Significant amounts of
CCIM and CCTS form early in the study (peak within a day), and show
decline afterwards.  Meanwhile HTID, CDTS and p-Toluamide form/peak late
in the studies (within days), and show only slight or no decline under
the conditions of the aqueous photolysis study.  Because of their late
formation, possibly persistent degradates HTID, CDTS and p-Toluamide are
therefore not expected to be important components in natural aquatic
systems.  Previously, the Metabolism Assessment Review Committee (MARC)
determined that these degradates will not be more toxic than the parent.
 In addition, based on the use pattern, and the nature of parent,
aqueous photolysis may not be a major route of degradation in most
natural environments.    SEQ CHAPTER \h \r 1  Although the MARC
recommended to exclude these degradates from drinking water assessment,
EFED is requesting hydrolysis/aerobic soil metabolism studies on the
degradate CCTS to confirm that degradates HTID, CDTS and p-Toluamide
were only photolytic degradates resulting from long exposure to light
energy in aqueous systems.

This assessment is considered national in scope for fruiting vegetables,
but regional for grapes.  No regional PCAs were used.

Due to the lack of data, the potential impact of drinking water
treatment on cyazofamid and its degradates concentrations constitute an
uncertainty. 

CONCLUSIONS 

The results of this DWA show that the uses that bring the highest
exposure to surface and ground drinking waters are turf and ornamentals
(reported in a previous review).  The new uses on fruiting vegetables
and grapes resulted in lower EDWCs.  The results reported represent a
timeline in which the parent and the degradates CCIM and CCIM-AM are
present initially.  These chemicals contribute to the surface water peak
EDWC.  Since the formation of the parent and two degradates are assumed
and modeled (full application rate for the parent, plus estimated
application rates for the degradates), the peak EDWC is likely an
overestimation.

For chronic exposure, the most conservative scenario is 100% conversion
of the parent to the terminal degradate CTCA.  This scenario of 100%
conversion was not observed in the aerobic soil metabolism studies and
is also likely an overestimation of the chronic EDWCs.  It is noted that
the chronic EDWCs are up to three and a half times larger than the peak
EDWC.

The ground water EDWC was <6% of the peak and chronic surface water
EDWCs, which indicates a lower contribution of the chemicals in ground
waters.  Once again, since 100% conversion was assumed to derive ground
water values, the EDWCs are possibly overestimated.

≥6).  The aerobic soil metabolism data was also used to derive the
aerobic aquatic metabolism input values for the degradates (the aerobic
aquatic metabolism input value is 2x the aerobic soil metabolism input
value, as per guidance).

This screening-level assessment is considered conservative.  A more
definitive assessment may be made, using the same tier 2 surface waters
aquatic model (PRZM/ EXAMS).  The application rates may be refined and
possibly regional PCAs may be used.

REFERENCES 

1. U.S. Environmental Protection Agency (2006). Guidance for Developing
a Tier I Drinking Water Exposure Assessment.
F:\USER\SHARE\Policies,Effects Assessments\d.Water Assessments\Surface
Water\Drinking Water

 

2. U.S. Environmental Protection Agency. Guidance on Characterization of
Drinking Water Exposure for Dietary Risk Assessment. Draft EFED Policy.

3.  U.S. Environmental Protection Agency (1999)  Estimating the Drinking
Water Component of a Dietary Exposure Assessment.    HYPERLINK
"http://www.epa.gov/oppfead1/trac/science/#drinking" 
http://www.epa.gov/oppfead1/trac/science/#drinking 

4. U.S. Environmental Protection Agency (2000a).  Development and Use of
Distributions of Pesticide Concentrations in Drinking Water for FQPA
Exposure Assessments. FIFRA SAP Meeting – February 29 – March 3,
2000.    HYPERLINK
"http://www.epa.gov/oscpmont/sap/meetings/2000/index.htm" 
http://www.epa.gov/oscpmont/sap/meetings/2000/index.htm .

5. June 2000: Monitoring Strategies for Pesticides in Surface-Derived
Drinking Water. FIFRA SAP Meeting –   HYPERLINK
"http://www.epa.gov/scipoly/sap/2000/june/finwateronly.pdf" 
http://www.epa.gov/scipoly/sap/2000/june/finwateronly.pdf 

6. U.S. Environmental Protection Agency (2000b). Progress Report on
Estimating Pesticide Concentrations in Drinking Water and Assessing
Water Treatment Effects on Pesticide Removal and Transformation.  
HYPERLINK "http://www.epa.gov/oscpmont/sap/meetings/2000/index.htm" 
http://www.epa.gov/oscpmont/sap/meetings/2000/index.htm 

7. U.S. Environmental Protection Agency (2000c) Drinking Water Screening
Level Assessment. Part A: Guidance for Use of the Index Reservoir in
Drinking Water Exposure Assessments. Part B: Applying a Percent Crop
Area Adjustment to Tier 2 Surface Water Model Estimates for Pesticide
Drinking Water Exposure Assessments. FIFRA SAP Meeting – September 1,
2000.  

  HYPERLINK "http://www.epa.gov/oppfead1/trac/science/reservoi.pdf" 
http://www.epa.gov/oppfead1/trac/science/reservoi.pdf .

8. SCIGROW: Users Manual (11/01/2001, revised 08/23/2002)

9. Guidance for Selecting Input Parameters in Modeling the Environmental
Fate and Transport of Pesticides, Version II (02/28/2002)

10. Food and Agriculture Organization of the United Nations.  FAO
PESTICIDE DISPOSAL SERIES 8.  Assessing Soil Contamination: A Reference
Manual.  Appendix 2. Parameters of pesticides that influence processes
in the soil.  Editorial Group, FAO Information Division: Rome, 2000.   
HYPERLINK "http://www.fao.org/DOCREP/003/X2570E/X2570E00.htm" 
http://www.fao.org/DOCREP/003/X2570E/X2570E00.htm  

Appendix A.  Structures of Cyazofamid and Relevant Degradation Products

Cyazofamid [IKF-916]



	IUPAC Name:
4-Chloro-2-cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfonamide.

CAS Name:
4-Chloro-2-cyano-N,N-dimethyl-5-(4-methylphenyl)-1H-imidizole-1-sulfonam
ide.

CAS Number:	120116-88-3.

SMILES String:	  SEQ CHAPTER \h \r 1
Cc1ccc(cc1)c1c(nc(n1S(=O)(=O)N(C)C)C#N)Cl

  SEQ CHAPTER \h \r 1 (ISIS v2.3/Universal SMILES).

No   SEQ CHAPTER \h \r 1 EPI Suite, v3.12 SMILES String found as of
6/28/06.









	









	



CCIM



	IUPAC Name:	4-Chloro-5-p-tolylimidazole-2-carbonitrile.

CAS Name:	Not reported.

CAS Number:	Not reported.









	









	CCIM-AM



	IUPAC Name:	4-Chloro-5-p-tolylimidazole-2-carboxamide.

CAS Name:	Not reported.

CAS Number:	Not reported.









	









	



CTCA



	IUPAC Name:	4-Chloro-5-p-tolylimidazole-2-carboxylic acid.

CAS Name:	Not reported.

CAS Number:	Not reported.









	









	

Appendix B. Sample Model Outputs

PRZM/EXAMS

For the parent cyazofamid, on CA tomato:

stored as Cyazofam.out

Chemical: Cyazofamid

PRZM environment: CAtomato_WirrigSTD.txt	modified Tueday, 29 May 2007 at
11:43:54

EXAMS environment: ir298.exv	modified Thuday, 29 August 2002 at 14:34:12

Metfile: w93193.dvf	modified Wedday, 3 July 2002 at 08:04:24

Water segment concentrations (ppb)

Year	Peak	96 hr	21 Day	60 Day	90 Day	Yearly

1961	0.2597	0.1595	0.1089	0.07954	0.05394	0.01333

1962	0.2548	0.1638	0.1136	0.07858	0.0532	0.01314

1963	0.3623	0.2325	0.1517	0.1217	0.08242	0.02036

1964	0.2398	0.1533	0.1072	0.07752	0.05258	0.01296

1965	0.7912	0.5077	0.2352	0.1307	0.08796	0.02172

1966	0.2378	0.1505	0.105	0.07467	0.05045	0.01246

1967	0.4721	0.3414	0.2071	0.1394	0.09402	0.02322

1968	0.2626	0.1686	0.1264	0.08822	0.05961	0.01469

1969	0.255	0.1588	0.106	0.0921	0.06205	0.01533

1970	0.2365	0.1489	0.1037	0.07591	0.05123	0.01265

1971	0.3936	0.2458	0.1536	0.09577	0.06639	0.01642

1972	0.2356	0.1456	0.1012	0.07376	0.05104	0.01298

1973	0.3581	0.2442	0.1602	0.0971	0.06542	0.01616

1974	0.2468	0.1844	0.1273	0.0886	0.0597	0.01474

1975	0.2485	0.1645	0.1185	0.08416	0.05681	0.01403

1976	0.2377	0.1499	0.1045	0.0771	0.05206	0.01324

1977	0.2456	0.1556	0.1109	0.07789	0.05401	0.01334

1978	0.3643	0.2393	0.1507	0.1176	0.07923	0.02079

1979	0.2454	0.1712	0.1189	0.08208	0.05536	0.01367

1980	0.2402	0.154	0.1077	0.07898	0.0535	0.01318

1981	0.3639	0.2517	0.1487	0.09662	0.06517	0.01608

1982	0.3559	0.2392	0.1708	0.1103	0.07425	0.01848

1983	1.274	0.791	0.2659	0.1597	0.11	0.02718

1984	0.2361	0.146	0.1015	0.07474	0.05045	0.01244

1985	0.2406	0.1544	0.1089	0.07653	0.05171	0.01303

1986	0.3111	0.2016	0.143	0.09064	0.06113	0.01509

1987	0.2632	0.1699	0.1207	0.08128	0.06504	0.01607

1988	0.3918	0.2684	0.1728	0.09964	0.06736	0.01659

1989	0.6768	0.4383	0.1809	0.1096	0.07697	0.01907

1990	0.3661	0.2416	0.1348	0.0887	0.07097	0.01763

Sorted results

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

0.032258064516129	1.274	0.791	0.2659	0.1597	0.11	0.02718

0.0645161290322581	0.7912	0.5077	0.2352	0.1394	0.09402	0.02322

0.0967741935483871	0.6768	0.4383	0.2071	0.1307	0.08796	0.02172

0.129032258064516	0.4721	0.3414	0.1809	0.1217	0.08242	0.02079

0.161290322580645	0.3936	0.2684	0.1728	0.1176	0.07923	0.02036

0.193548387096774	0.3918	0.2517	0.1708	0.1103	0.07697	0.01907

0.225806451612903	0.3661	0.2458	0.1602	0.1096	0.07425	0.01848

0.258064516129032	0.3643	0.2442	0.1536	0.09964	0.07097	0.01763

0.290322580645161	0.3639	0.2416	0.1517	0.0971	0.06736	0.01659

0.32258064516129	0.3623	0.2393	0.1507	0.09662	0.06639	0.01642

0.354838709677419	0.3581	0.2392	0.1487	0.09577	0.06542	0.01616

0.387096774193548	0.3559	0.2325	0.143	0.0921	0.06517	0.01608

0.419354838709677	0.3111	0.2016	0.1348	0.09064	0.06504	0.01607

0.451612903225806	0.2632	0.1844	0.1273	0.0887	0.06205	0.01533

0.483870967741936	0.2626	0.1712	0.1264	0.0886	0.06113	0.01509

0.516129032258065	0.2597	0.1699	0.1207	0.08822	0.0597	0.01474

0.548387096774194	0.255	0.1686	0.1189	0.08416	0.05961	0.01469

0.580645161290323	0.2548	0.1645	0.1185	0.08208	0.05681	0.01403

0.612903225806452	0.2485	0.1638	0.1136	0.08128	0.05536	0.01367

0.645161290322581	0.2468	0.1595	0.1109	0.07954	0.05401	0.01334

0.67741935483871	0.2456	0.1588	0.1089	0.07898	0.05394	0.01333

0.709677419354839	0.2454	0.1556	0.1089	0.07858	0.0535	0.01324

0.741935483870968	0.2406	0.1544	0.1077	0.07789	0.0532	0.01318

0.774193548387097	0.2402	0.154	0.1072	0.07752	0.05258	0.01314

0.806451612903226	0.2398	0.1533	0.106	0.0771	0.05206	0.01303

0.838709677419355	0.2378	0.1505	0.105	0.07653	0.05171	0.01298

0.870967741935484	0.2377	0.1499	0.1045	0.07591	0.05123	0.01296

0.903225806451613	0.2365	0.1489	0.1037	0.07474	0.05104	0.01265

0.935483870967742	0.2361	0.146	0.1015	0.07467	0.05045	0.01246

0.967741935483871	0.2356	0.1456	0.1012	0.07376	0.05045	0.01244

0.1	0.65633	0.42861	0.20448	0.1298	0.087406	0.021627

					Average of yearly averages:	0.0160023333333333

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: Cyazofam

Metfile:	w93193.dvf

PRZM scenario:	CAtomato_WirrigSTD.txt

EXAMS environment file:	ir298.exv

Chemical Name:	Cyazofamid

Description	Variable Name	Value	Units	Comments

Molecular weight	mwt	324.79	g/mol

Henry's Law Const.	henry	4e-7	atm-m^3/mol

Vapor Pressure	vapr	1e-7	torr

Solubility	sol	1.07	mg/L

Kd	Kd		mg/L

Koc	Koc	1338	mg/L

Photolysis half-life	kdp	0.02	days	Half-life

Aerobic Aquatic Metabolism	kbacw	16.4	days	Halfife

Anaerobic Aquatic Metabolism	kbacs	17.7	days	Halfife

Aerobic Soil Metabolism	asm	5.5	days	Halfife

Hydrolysis:	pH 7	11.9	days	Half-life

Method:	CAM	2	integer	See PRZM manual

Incorporation Depth:	DEPI	0.0	cm

Application Rate:	TAPP	0.0850	kg/ha

Application Efficiency:	APPEFF	0.99	fraction

Spray Drift	DRFT	0.064	fraction of application rate applied to pond

Application Date	Date	11-03	dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1	interval	7	days	Set to 0 or delete line for single app.

app. rate 1	apprate	0.0850	kg/ha

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

app. rate 2	apprate	0.0850	kg/ha

Interval 3	interval	21	days	Set to 0 or delete line for single app.

app. rate 3	apprate	0.0850	kg/ha

Interval 4	interval	7	days	Set to 0 or delete line for single app.

app. rate 4	apprate	0.0850	kg/ha

Interval 5	interval	7	days	Set to 0 or delete line for single app.

app. rate 5	apprate	0.0850	kg/ha

Record 17:	FILTRA	

	IPSCND	1

	UPTKF	0

Record 18:	PLVKRT	0

	PLDKRT	0

	FEXTRC	0.5

Flag for Index Res. Run	IR	Reservoir

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

SCI-GROW

	Sample run for CTCA:

                           SCIGROW

                          VERSION 2.3

            ENVIRONMENTAL FATE AND EFFECTS DIVISION

                 OFFICE OF PESTICIDE PROGRAMS

             U.S. ENVIRONMENTAL PROTECTION AGENCY

                        SCREENING MODEL

                FOR AQUATIC PESTICIDE EXPOSURE

 

 SciGrow version 2.3

 chemical:CTCA_Scenario_3

 time is  2/12/2009   8:37:57

 -----------------------------------------------------------------------
-

  Application      Number of       Total Use    Koc      Soil Aerobic

  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism
(days)

 -----------------------------------------------------------------------
-

      1.137           2.0           2.274      7.08E+02    10000.0

 -----------------------------------------------------------------------
-

 groundwater screening cond (ppb) =   2.18E+00 

 ***********************************************************************
*

 They include okra, tomato, ground cherry, tomatillo, bell pepper, chili
pepper, cooking pepper, pimento, sweet peppers, eggplant and pepino plus
okra.

ግ䅐䕇†കഀ഍倓䝁⁅ᐠᔱ

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