Document ID: EPA-HQ-OPP-2007-0234-0007
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-10-24T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

                                                                     
OFFICE OF 

                                                                 
PREVENTION, PESTICIDES AND

                                                                   
TOXIC SUBSTANCES

  SEQ CHAPTER \h \r 1 								 PC Code 	129098

				 DP Barcode	D334948, D334950

MEMORANDUM

DATE:	February 7, 2007

SUBJECT:	Tier I Estimated Drinking Waters Concentrations of Fluazinam
and Total Residues for the Use in the Human Health Risk Assessment; IR4
Petition for the Use of Fluazinam on Edible-Podded Legume Vegetables
(except peas), Bushberry (crop subgroup 13B), Brassica (Cole) Leafy
Vegetables, Ginseng, and Dry, and Succulent Bean Crop Subgroup 6B
(except peas)

TO:		Shaja Brothers, Risk Manager Reviewer

		Daniel Rosenblatt, Chief

		Barbara Madden, Chief

		Minor Use Branch

		Registration Division (7505P)

AND:		Kelly Schumacher

		Cristina Swartz, Chief 

		Registration Action Branch II

		Health Effects Division (7509P)

FROM:	José Luis 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 memo presents the Tier I Estimated Surface Drinking
Water Concentrations and Estimated Ground Water Concentrations (EDWCs)
for Fluazinam (CAS name
3-chloro-N-[3-chloro-2,6-dinitro-4-(trifluoromethyl)phenyl]-5-(trifluoro
methyl)-2-pyridinamine, CAS no. 79622-59-6) and Fluazinam Total Residues
(fluazinam plus its major transformation products), calculated using the
Tier I aquatic models FIRST and SCI-GROW, respectively, for use in the
human health risk assessment.

            The Estimated Drinking Water Concentrations (EDWCs) for
Fluazinam and Fluazinam Total Residues were calculated based on a
maximum application rate of 3.90 lb a.i./A/season of fluazinam.  In
addition to the EDWC’s for Fluazinam, EDWC’s were calculated for
Total Fluazinam Residues because the environmental fate studies
indicated that the parent compound forms transformation compounds which
are similar in structure to the parent under most conditions.

For parent Fluazinam, the surface water acute value is 71.0 ppb, and the
chronic value is 0.7 ppb.  The groundwater screening concentration is
0.187 ppb of Fluazinam.  These values represent upper-bound estimates of
the concentrations of the chemical that might be found in surface water
and groundwater due to the use of Fluazinam on bushberries at the
maximum application rate of 3.90 lb a.i./A/season.

            For Total Fluazinam Residues, the surface water acute value
is 71.0 ppb and the chronic value is 17.7 ppb.  The groundwater
screening concentration is 0.187 ppb.  These values represent
upper-bound estimates of the concentrations of  Total Residues of
Fluazinam that might be found in surface water and groundwater due to
the use of Fluazinam on bushberries at the maximum application rate of
3.90 lb a.i./A/season.

            Should the results of this assessment indicate a need for
further refinement, please, contact EFED as soon as possible so that we
may schedule a Tier II assessment.

Data Gaps:

Additional data has been requested to upgrade the Photolysis in Water
and Photodegradation on Soil data requirements.  The additional
information will refine the information about the quantitation of the
parent and degradates.  In addition, EFED believes that the available
Terrestrial Field Dissipation Studies provide useful information about
the parent fluazinam.  However, poor recoveries for two of the
transformation products upon storage stability cast doubts over the
results obtained for them in the field.  At this time, only one new
study is required, on a typical site, with a concurrent storage
stability study.

EXECUTIVE SUMMARY 

Fluazinam, CAS Name:
3-chloro-N-[3-chloro-2,6-dinitro-4-(trifluoromethyl)phenyl]-5-(trifluoro
methyl)-2-pyridinamine, and IUPAC Name:
3-chloro-N-(3-chloro-5-trifluoromethyl-2-pyridyl)-α,α,α-trifluoro-2,6
-dinitro-p-toluidine, has a CAS Number of 79622-59-61 and a PC Code of
129098.  It is a pyridine (dinitroaniline) fungicide.  The structure
consists of one phenyl ring with two nitro groups, and a pyridine ring. 
Both rings have a trifluoromethyl group.  The rings are attached by a
nitrogen (amine).

Fluazinam is a new protectant and contact fungicide, a phenyl
pyridinamine.  It is an uncoupler of oxidative phosphorilation in the
respiration chain involving protonation/deprotonation (it inhibits
fungal respiration, and the production of energy within the fungus). 

Fluazinam is currently used only on potatoes and peanuts.  The product
name is Omega 500F Agricultural Fungicide (EPA Reg. No. 71512-1).  It
contains 40.0% fluazinam.  It is being proposed in a Section 3 (IR4)
petition, for use on edible-podded legume vegetables (except peas),
bushberry (crop subgroup 13B), brassica (cole) leafy vegetables,
ginseng, and dry, and succulent bean crop Subgroup 6B (except peas). 
The application methods vary with the crops.  For example, aerial
applications are prohibited, but the material may be applied by
sprinkler irrigation, or, for brassica leafy vegetables, it may be
applied by soil incorporation prior to transplanting.  

This is a Tier I screening assessment using Tier 1 aquatic models
SCI-GROW and FIRST, and maximum application rates for fluazinam, with
minimum application intervals.  It was found that the worse case
scenario was bushberry, with the highest application rate, and the
highest PCA.  In addition to the parent fluazinam, the total residues
were modeled because fluazinam is transformed relatively rapidly into
various transformation products that resemble the parent structure.

At this time, the persistence of fluazinam transformation products is
uncertain because the information about these compounds from terrestrial
field dissipation studies has been deemed invalid.  The aquatic
metabolism studies signal high persistence of such degradates.  A new
terrestrial field dissipation study has been required.  In addition, the
extent and importance of photolysis is not very clear because the
supplemental data available is not quantitative.  EFED requested
additional data from such studies to clarify this point.

Table 1 provides a summary of the Tier I modeled drinking water
concentrations.  In addition to the EDWC’s for Fluazinam, EDWC’s
were calculated for Total Fluazinam Residues because the environmental
fate studies indicated that the parent compound forms transformation
compounds which are similar in structure to the parent under most
conditions.  Should there be a need for additional refinements, the EFED
can perform a Tier II aquatic assessment, for surface waters.

Table 1.  Maximum Tier I Estimated Drinking Water Concentrations (EDWCs)
for drinking water assessment based on ground application of fluazinam.

DRINKING WATER SOURCE (MODEL USED) 	USE (rate modeled)	MAXIMUM ESTIMATED
DRINKING WATER CONCENTRATION  (EDWC)  ( ppb) 

Groundwater

(SCI-GROW) Fluazinam and Total Residues of Fluazinam	Bushberries (3.90
lb a.i./A)	Acute and Chronic	0.187

Surface Water

(FIRST) Fluazinam	Bushberries (3.90 lb a.i./A)	Acute	71.0

	Bushberries (3.90 lb a.i./A)	Chronic	0.7

Surface Water

(FIRST) Total Residues of Fluazinam	Bushberries (3.90 lb a.i./A)	Acute
71.0

	Bushberries (3.90 lb a.i./A)	Chronic	     17.7

PROBLEM FORMULATION

This is a Tier I drinking water assessment that uses modeling and
available monitoring data 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.  This initial tier screens out chemicals with low potential
risk and provides estimated exposure concentrations for the human health
dietary risk assessment.  

ANALYSIS

Use Characterization

A summary table of all use patterns, new uses and modeled uses, is
illustrated below (Table 2).  The crop groups bolded are the proposed
ones.

  SEQ CHAPTER \h \r 1 Table 2.  Summary use information for fluazinam,
based on Omega 500F label (EPA Reg. No. 71512-1).

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

Peanut 	0.78	~2.66	2.10	21	Sprinkler irrigation	0

Potato	0.26	7	1.82	7	Sprinkler irrigation	0

Crop Subgroup 6A, Edible-Podded Legume Vegetables except peas, such as,
but not limited to: Phaseolus spp. Such as: runner bean, snap bean, wax
bean; Vigna spp. Such as: asparagus bean, Chinese longbean, moth bean,
yardlong bean; jackbean, and sword bean	0.44	2	0.91	7	Sprinkler
irrigation	14

Dry Bean, and Succulent Bean Crop Subgroup 6B, except Peas (such as, but
not limited to lima bean)	0.44	2	0.91	7	Sprinkler irrigation	30

Crop Subgroup 13B, Bushberry, such as, but not limited to: Aronia berry,
blueberry (highbush and lowbush), Chilean guava, currant (Buffalo,
black, red, and Native), elderberry, European barberry, gooseberry,
highbush cranberry, honeysuckle, huckleberry, jostaberry, juneberry,
lingonberry, salal, and sea buckthorn	0.65	6	3.90	7	Sprinkler irrigation
30

Crop Group 5, Brassica (Cole) Leafy Vegetables, such as, but not limited
to: broccoli; broccoli raab (rapini); Chinese cabbage (napa);
cauliflower; collards, kale; mizuna; mustard spinach; turnip greens;
Chinese broccoli; Brussels sprouts; Chinese cabbage (bok choy); Chinese
mustard cabbage; cavalo broccoli; kohlrabi; mustard greens; rape greens
[Trans-plant 6.45 fl oz/100 gal or presu-mably 0.64 lb a.i./A]

Soil incorpo-ration 1.36 at a soil depth of 6-8 in	1	2.00	N/A	Soil
drench or soil incorpo-ration	20;

50 for heading vegeta-bles such as cabbage and broccoli

Ginseng	0.78	4	3.12	7	Sprinkler irrigation	30

The usual application method for fluazinam is sprinkler irrigation;
however, it can be soil incorporated before transplant, for soils with
low infiltration rates, for Crop Group 5, Brassica (Cole) Leafy
Vegetables.  Fluazinam may not be applied aerially.

The label specifies a buffer zone of 25 ft within aquatic areas (lakes,
reservoirs, rivers, permanent streams, marshes or natural ponds, and
estuaries) so as to allow growth of a vegetative filter strip.

The use pattern selected for modeling was bushberry.  It has the maximum
total application rate, and it is applied by sprinkler irrigation, which
may cause more drift towards the standard pond than the soil
incorporated brassica group 5, it also has the highest PCA (default,
87%).   With six applications, at seven-day interval, it is likely that
this scenarios will provide the highest chronic exposure as well.

Fate and Transport Characterization

A detailed summary of physical/chemical and environmental fate/transport
properties of the pesticide, including measured parameters, values, data
sources, and comments, is included in Table 3.

Table 3.  Summary of physical/chemical and environmental fate and
transport properties of <pesticide>.  <EXAMPLE>

PARAMETER	VALUE(S) (units)	SOURCE	COMMENT

  Chemical Name
3-chloro-N-[3-chloro-2,6-dinitro-4-(trifluoromethyl)phenyl]-5-(trifluoro
methyl)-2-pyridinamine	EPA Pesticide Fact Sheet	–

  Molecular Weight	465.1	PMRA Regulatory Note REG2003-12, 10/27/03	–

  Solubility (20 oC)	0.025 mg/L @ pH 5.5; 0.071 mg/L @ pH 7.0	MRID:
42208403.	–

  Vapor Pressure (20 oC)	8.25 x 10-6 mm Hg	MRID: 42248403.	–

  Henry’s Law constant	1.81 x 10-3 atm-m3/mol	

MRID: 46235701.	Estimated from vapor pressure and water solubility.

  pKa (20 oC)	7.22 in 50% ethanol-water	EPA Pesticide Fact Sheet	–

 Octanol-Water Partition Coefficient 

 (KOW,  at 20 oC)	3620; log POW = 3.56	EPA Pesticide Fact Sheet	–

  Hydrolysis Half-life 

  (pH 5, 7, 9; (25 oC))	pH 5  stable              pH 7  42 days         
  pH 9  6 days	MRID: 42208412.	Fluazinam + degradates: Stable at all
pHs.

  Aqueous Photolysis Half-life	t1/2  = 2.5 days           dark control =
stable	MRID: 44807312, 43521009(s).	One degradate was a tricyclic
compound.

  Soil Photolysis Half-life	t1/2  = 35.0 days,    value corrected for
dark control	MRID: 44807313(s).	Degradates at ≤10% of the applied.

  Aerobic Soil Metabolism Half-life	t1/2  = 132 days	MRID: 42208413(c).
Degradates at ≤10% of the applied.

  Anaerobic Aquatic Metabolism   

  Half-life	~⅓ day (or approximately 8 hours)

	MRID: 43521010(c).	Fluazinam + degradates ~ stable

  Aerobic Aquatic Metabolism 

  Half-life	t1/2  = 4.0-7.4 hours

	MRID: 44807314(c).	Fluazinam + degradates = 51-71 days

  FLUAZINAM Soil Partition Coefficient (Kd)	11.12, 43.48, 27.19, 37.88
ml/g

	MRID: 42248628, 42974913.	–

  FLUAZINAM Soil Partition Coefficient (KOC)	2316, 1705, 1915, 1894 mL/g
MRID: 46235732.	–

  AGED FLUAZINAM Column Leaching	0.66%; >>80% remained in the top soil
MRID: 42208415.	–

  HYPA Soil Partition Coefficient (Kd)	14, 13, 26, 8.1, 4.3, 19 ml/g

	MRID: 43528201.	–

  HYPA Soil Partition Coefficient (KOC)	450, 700, 1700, 450, 920, 1300
mL/g	MRID: 43528201.	–

  CAPA Soil Partition Coefficient (Kd)	28, 11, 4.9, 67 ml/g

	MRID: 44807315.	–

  CAPA Soil Partition Coefficient (KOC)	1289, 1317, 1876, 3784 mL/g
MRID: 44807315.	–

  Terrestrial Field Dissipation 

  Half-life	Range from 9 to 49 days:  Ephrata, WA: DT50~9 days loamy
sand, pinto beans; Kempton, ND: half-life=49 days, sandy loam, beans; 
Porterville, CA: half-life=20 days, loamy sand, beans;                  
 Montezuma, GA

The degradation was biphasic.	MRID: 44807318, 44807320, 44807316,
44807319, 44807317.	–

Bioaccumulation in Fish	348X  Fillet              1220X  Whole fish     
  ≥67% of residues depurated after 21 days from the fillet	MRID:
43521012.	_

Based on the properties of the chemical, applications of fluazinam are
likely to reach the target (the crop), but drift is also possible.  The
chemical has a low vapor pressure, and a moderate Henry’s Law
constant.  Due to the fact that it appears to show relatively short half
lives in aquatic media, and it binds to soils, EFED believes that the
chemical would not volatilize substantially.

EFED concludes that fluazinam appears to degrade at moderate to low
rates in aerobic soils, but it is more rapidly transformed into other
compounds of similar backbone structure in high pH solutions or in
aquatic media, both, aerobic or anaerobic.  Fluazinam may be photolyzed
relatively rapidly (2.5 days) to form a tricyclic compound (G-504).  The
total fluazinam residues (fluazinam and its transformation products) are
persistent in most environments (aerobic aquatic metabolism 51-71 days,
relatively stable in anaerobic aquatic environment) and are likely to
reach aquatic media as a totality through runoff.  Since fluazinam does
not alter substantially its backbone structure in the environment, but
instead, goes through a slight transformation of functional groups, EFED
considered parent and transformation products together when making
assessments.

While the parent and two transformation products, HYPA and CAPA, have
relatively low mobility, indicating a relatively low potential for
ground water contamination, further information on the other
transformation products should be required in a new terrestrial field
dissipation study.

Fluazinam shows a potential to bioaccumulate in fish (BCF=1220X for
whole fish; ≥67% of residues depurated in 21 days).

The fate and transport characterization also summarizes the various
degradation products formed by each process in the studies reviewed in
tabular form. (Table 4)

Table 4.  Summary of degradate formation from degradation of fluazinam.

STUDY TYPE	DEGRADATE and MAXIMUM CONCENTRATION	SOURCE

	CAPA (% applied)	HYPA (% applied)	AMPA (% applied)

	  Hydrolysis	34% at 28 days pH 7; 84-85% at 20 days at pH 9	–	–	 
MRID: 42208412.

  Aqueous Photolysis	G-504 was 14.0-17.1% by 7-10 days	_	–	  MRID:
444807312, 43521009.

  Soil Photolysis	_	Detected at more than dark control	Detected at more
than dark control	  MRID: 44807313.

  Aerobic Soil Metabolism	_	Detected 	MAPA and DAPA also detected	 
MRID: 42208413.

  Aerobic Aquatic Metabolism	_	–	24.2% at 0.2 day; DAPA: at day 30;
SDS-67200 39.6%by day 14	MRID: 43521010.

 Anaerobic Aquatic Metabolism 

	12.6% at 72 hr	–	DAPA: 19.0% by 240 hr; DCPA: 11.3% at 24 hr	MRID:
44807314.

 Terrestrial Field Dissipation	MAPA, CAPA, and HYPA were monitored;
however, there were problems with the storage stability data	MRID:
various.

Drinking Water Exposure Modeling

  SEQ CHAPTER \h \r 1 

Models

Brief description of the models used:

SCI-GROW (v 2.3, 8/5/03) (Screening Concentration in Ground Water) 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. 1 and
2)

FIRST (v 1.1.0, 12/18/07) (FQPA Index Reservoir Screening Tool) is a
metamodel of PRZM and EXAMS used as a screening tool to estimate
pesticide concentrations found in surface water used as drinking water. 
FIRST was developed by making multiple runs of PRZM using varying
sorption coefficients and determining the concentration in the EXAMS
index reservoir scenario after a two-inch single storm event.  (The
Index Reservoir is a standard water body used by the Office of Pesticide
Programs to assess drinking water exposure (Office of Pesticide
Programs, 2002).  It is based on a real reservoir (albeit not currently
in active use as a drinking water supply), Shipman City Lake in
Illinois, that is known to be vulnerable to pesticide contamination.) 
The single runoff event moves a maximum of 8% of the applied pesticide
into the reservoir.  This amount can be reduced by degradation or
effects of binding to soil in the field.  Additionally, FIRST can
account for spray drift and adjusts for the area within a watershed that
is planted with the modeled crop (Percent Cropped Area).   Spray drift
(modeled as direct deposition of the pesticide into the reservoir) is
assumed to be 16% of the applied active ingredient for aerial
application, 6.3% for orchard air blast application, and 6.4% for other
ground spray application. Despite being a single event model, FIRST can
account for spray drift from multiple applications.  The default
agricultural Percent Cropped Area (PCA) is 87%.  The PRZM scenario used
for FIRST development was among the most vulnerable, and thus resulting
surface water concentrations represent the upper bound values on the
concentrations that might be found in drinking water from the use of a
pesticide.  (Ref. 1, 3 and 4)

For volatile and semi-volatile compounds, Tier I modeling will tend to
over-estimate surface water EDWCs because there are no parameters in
FIRST that explicitly take into account volatility (ie., no vapor
pressure or Henry’s Law constant inputs).  Therefore, in reality, more
of the compound will be volatilizing than Tier I can account for.  If
drinking water levels of concern are exceeded for over-estimated Tier I
surface water EDWCs, Tier II modeling will be able to refine these EDWCs
by including volatility, Henry’s Law, diffusion in air, and enthalpy
considerations.  Since SCI-GROW is a regression model developed from
actual pesticide data with a range of volatilities, systematic
conclusions cannot be drawn about over or underestimation of groundwater
EDWCs at Tier I. 

Modeling Approach and Input Parameters

Tables of modeling parameter input values for SCI-GROW and FIRST (Tables
5 and 6, respectively) based on the current input parameter guidance
(Ref. 5) are included.

In addition to the EDWC’s for Fluazinam, EDWC’s were estimated for
Total Fluazinam Residues because the environmental fate studies
indicated that the parent compound forms transformation compounds which
are similar in structure to the parent under most conditions.  The input
parameters were selected according to the similarity observed in the
mobility characteristics of fluazinam, HYPA, and CAPA.  

It was observed that the KOC model was better to describe the mobility
of fluazinam.  Only one value of aerobic soil metabolism was available,
but two values of aerobic aquatic metabolism were available.  It is
noted that the aerobic aquatic metabolism is only 10.9 hours.  A ground
application method was utilized.

  

For the total residues, the half-life was calculated taking into
consideration the transformation products plus fluazinam.  This applied
for the aerobic aquatic metabolism (91.8 days for total residues, in
contrast to 10.9 hours for fluazinam), and the hydrolysis (relatively
stable for total residues vs. 42 days for fluazinam).  For the
hydrolysis study, the transformation product that is formed is CAPA.  In
the aerobic aquatic metabolism study, the transformation products formed
are DCPA, CAPA, and DAPA, plus various minor transformation products.
For other parameters, in the absence of a suitable value, it was assumed
that the value for fluazinam was similar to that for the total residues
because they had similar structures.

Table 5. SCI-GROW (v 2.3) input parameter values for fluazinam and total
residues of fluazinam, use on bushberries1.

PARAMETER (units)	FLUAZINAM	TOTAL RESIDUES	SOURCES AND COMMENTS

Maximum Application Rate (lb a.i./A)	0.65	Proposed label.

Number of Applications per Year	6	Proposed label.  Represents
most-conservative scenario in which the total maximum rate is applied in
six applications.

Organic Carbon Partition Coefficient (Koc; mL/g)	1904.5	Represents the
median value of four values ranging from 1705 to 2316 mL/g for the
parent compound. 

Aerobic Soil Metabolism Half-life (days)	132	Represents one value for
the aerobic soil metabolism of the parent compound.

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.

Table 6. FIRST (v 1.1.0) input parameter values for fluazinam and total
residues of fluazinam, use on bushberries1.

PARAMETER (units)	FLUAZINAM	TOTAL RESIDUES	SOURCES AND COMMENTS

Application Rate (lb a.i./A)	0.65	0.65	Proposed label.

Number of Applications	6	6	Proposed label.

Interval between Applications (days)	7	7	Proposed label.

Percent Cropped Area (decimal)	0.87	0.87	National default.

Soil Partition Coefficient (Kd; (mL/g) or KOC (mL/gOC))	1894	1894
Represents the lowest non-sand KOC value among four values ranging from
1705 to 2316 mL/g.  The KOC model is better for this chemical. 

Aerobic Soil Metabolism Half-life (days)	396	396	Determined by
multiplying the calculated half-life (132 days) by 3 to account for the
uncertainty associated with using a single value.

Wetted in?	No	No	Proposed label.

Depth of Incorporation (inches)	0	0	Proposed label.

Method of Application	Ground application	Ground application	Proposed
label.

Solubility in Water @ 20 OC, unbuffered (mg/L or ppm)	0.071	0.071
Maximum available value, at pH 7.

Aerobic Aquatic Metabolism Half-life (days)	0.454	91.8	 Represents the
90th percentile of the upper confidence bound on the mean of two
half-life values (4.0 hr and 7.4 hr: mean 5.7 hr, std. dev. 2.40 hr, the
value is 10.9 hr or 0.454 days).  For total residues two half-lives (51
and 71 days: mean 61 days, std. dev. 14.14 days)

Hydrolysis Half-life @ pH 7 (days)	42	Stable	The transformation product
CAPA reaches a maximum at the end of the study at pH 7.

Aquatic Photolysis Half-life  @ pH 7 (days)	2.5	2.5	From aqueous
photolysis study

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

The Percent Cropped Area (PCA) used was the National Default of 0.87, it
is intended for use on other crops for which no PCA has been developed. 
Options for Tier I are national scale cotton, wheat, corn, soybeans, or
default; regional PCAs are a Tier II tool intended for refined
assessment. (Ref. 6)

Modeling Results

Table 7 summarizes the modeling results for all model runs.

Table 7.  Maximum Tier I Estimated Drinking Water Concentrations (EDWCs)
for drinking water risk assessment based on ground application of
fluazinam.

DRINKING WATER SOURCE (MODEL USED) 	USE (rate modeled)	MAXIMUM ESTIMATED
DRINKING WATER CONCENTRATION  (EDWC)  ( ppb) 

Groundwater

(SCI-GROW) Fluazinam and Total Residues of Fluazinam	Bushberries (3.90
lb a.i./A)	Acute and Chronic	0.187

Surface Water

(FIRST) Fluazinam	Bushberries (3.90 lb a.i./A)	Acute	71.0

	Bushberries (3.90 lb a.i./A)	Chronic	0.7

Surface Water

(FIRST) Total Residues of Fluazinam	Bushberries (3.90 lb a.i./A)	Acute
71.0

	Bushberries (3.90 lb a.i./A)	Chronic	     17.7

SCIGROW concentration (ppb) represents the groundwater concentration
that might be expected in shallow unconfined aquifers under sandy soils.
Output is used for both acute and chronic endpoints.

FIRST concentrations (ppb) represent untreated surface water
concentrations.

 

The one-in-10-year peak day concentration is used for acute endpoints
and the one-in-10-year annual average concentration is used for chronic
endpoints. 

The estimated concentrations provided in this assessment are
conservative estimates of concentrations in drinking water.  If dietary
risks require refinement, higher tiered crop-specific and
location-specific models and modeling scenarios can be used.

Monitoring Data

No monitoring data are available for fluazinam.

Drinking Water Treatment

It is likely that primary treatment may reduce the levels of fluazinam
due to its tendency to bind.  However, there is no information available
at this time to determine the levels of reduction.  On the other hand,
fluazinam is very short lived in aquatic environments, forming various
other transformation products. (Ref. 9) 

CONCLUSIONS 

This is a Tier I level analysis, refinements may be available should
they be needed.  The acute levels of surface drinking waters was 71.0
ppb, the chronic level of drinking waters was 0.7 ppb of fluazinam.  The
groundwater concentration of fluazinam, suitable for acute and chronic
is 0.187 ppb.  The peak concentration was limited by the solubility
limit of fluazinam.  It was assumed that the maximum application rate
was used on bushberries, with the minimum interval between applications.

For the total residues of fluazinam, the acute levels of surface
drinking waters was 71.0 ppb, the chronic level of drinking waters was
17.7 ppb of total residues.  The groundwater concentration of total
residues of fluazinam, suitable for acute and chronic is 0.187 ppb.  The
peak concentration was also limited by the solubility limit of
fluazinam.

It was assumed that for the total residues of fluazinam, the properties
of fluazinam were applicable, for example, the solubility, which is the
limiting factor in the peak concentration.  Another example is the
mobility.  It may be slightly different for each transformation product,
while it was assumed that it was the same than the parent fluazinam. 
These assumptions make the assessment uncertain.  A more definitive
assessment could be made with the expenditure of additional resources,
and given the availability of additional data.

The total residues approach is conservative with uncertainties due to
unavailability of degradate information.  A Tier II assessment could
involve input from additional studies (not available at this time) and
refine the risk assessment.

APPENDIX

Molecular structure of fluazinam and its degradation products.

FLUAZINAM

CAPA

SCIGROW and FIRST model output files.

                           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:Fluazinam

 time is  1/23/2007   8:40: 1

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

  Application      Number of       Total Use    Koc      Soil Aerobic

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

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

      0.650           6.0           3.900      1.90E+03      132.0

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

 groundwater screening cond (ppb) =   1.87E-01 

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

 

   RUN No.   1 FOR Fluazinam        ON   Bushberrie    * INPUT VALUES * 

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPB )   (%DRIFT)     AREA    (IN)

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

   .650(  3.783)   6   7    1894.0   71.0   GROUND( 6.4)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.) 

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

    396.00        2          N/A      2.50-  310.00      .45       .45

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

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

             71.000                       .660

   RUN No.   2 FOR Fluaz. Res.      ON   Bushberrie    * INPUT VALUES * 

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPB )   (%DRIFT)     AREA    (IN)

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

   .650(  3.431)   6   7    1894.0   71.0   GROUND( 6.4)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.) 

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

     91.80        2          N/A       .00-     .00    91.80     91.80

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

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

             71.000                     18.542

   RUN No.   3 FOR Fluaz. Res. Conf ON   Bushberrie    * INPUT VALUES * 

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPB )   (%DRIFT)     AREA    (IN)

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

   .650(  3.783)   6   7    1894.0   71.0   GROUND( 6.4)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.) 

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

    396.00        2          N/A      2.50-  310.00    91.80     70.83

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

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

             71.000                     17.697

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

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␃愀$ᨀPolicy Establishing Current Versions of Exposure Models and
Responsibility for Model Maintenance (11/06/2002)

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

FIRST Users Manual (08/01/2001)

FIRST: A Screening Model to Estimate Pesticide Concentrations in
Drinking Water (05/01/2001)

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

  SEQ CHAPTER \h \r 1 Use of the Index Reservoir and Percent Crop Area
in EFED Drinking Water Assessments (12/01/1999)

Golf Course Adjustment Factors for Simulated Aquatic Exposure
Concentrations (06/01/2005)

  SEQ CHAPTER \h \r 1 Policy for Estimating Aqueous Concentrations from
Pesticides Labeled for Use on Rice (10/29/2002)

The Incorporation of Water Treatment Effects on Pesticide Removal and
Transformations in Food Quality Protection Act (FQPA) Drinking Water
Assessments  (10/25/2001)

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