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OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

PC Code: 125501

Chemical: Clofentezine

DP Barcode: 423336

May 27, 2015

MEMORANDUM

SUBJECT:   Clofentezine ‐ Drinking Water Assessment for Proposed New Use on Avocado,

Papaya, and Crop Group Expansions for Pome fruit (11‐10), Cherry Subgroup (12‐

12A), Peach Subgroup (12‐12B), and Small Fruit, Vine Climbing (except Fuzzy

Kiwi) (Subgroup 13‐07F).

TO: Barbara Madden, Team Leader, RM 05

    Andy Ertman, Risk Manager

    Minor Use and Emergency Response Branch

    Registration Division (7505P)   

   

    Venus Eagle, Product Manager 01

    Marianne Lewis, Risk Manager

    Insecticide Branch

    Registration Division (7505P)

THROUGH: Dana Spatz, Branch Chief

    Environmental Risk Branch 3

    Environmental Fate and Effects Division (7507P)

FROM:   Rosanna Louie‐Juzwiak, Risk Assessment Process Leader

    Environmental Risk Branch 3

    Environmental Fate and Effects Division (7507P)

The Interregional Research Project No. 4 (IR‐4) has petitioned EPA to register the use of

clofentezine on Avocado, Papaya, and Crop Group Expansions for Pome fruit (11‐10), Cherry

Subgroup (12‐12A), Peach Subgroup (12‐12B), and Small Fruit, Vine Climbing (except Fuzzy Kiwi)

(Subgroup 13‐07F) on the Apollo® SC end‐use product label, EPA Reg. No. 66222‐47 (refer to

Table 1 for a summary of the uses). The proposed application rate is the same as for the
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existing registered crops, i.e., a maximum of one application per year, at the maximum rate of

0.25 pound of active ingredient per acre. Applications can only be made foliarly via ground

application equipment.  

Table 1. Summary of Clofentezine Uses

Registered Use Sites   Proposed Additional Use sites (Crop Group or Subgroup)

Apples

Pome fruit (11‐10)

Crop group expansion

Apricot, Peach, Nectarine

Peach Subgroup (12‐12B)

Crop group expansion

Cherry Cherry Subgroup (12‐12A)

Crop group expansion

Grape

Small Fruit, Vine Climbing (except Fuzzy Kiwi) (13‐07F)

Crop group expansion

Persimmon Avocado

Almond and Walnut Papaya

Pears

Christmas Trees

Forestry trees grown in greenhouses

Ornamental plants (nonbearing trees;

shrub; vine; herbaceous plants)

EFED previously conducted a drinking water assessment using PRZM‐EXAMS with EXPRESS shell

interface and SCI‐GROW to estimate drinking water concentrations in surface water and

groundwater, respectively, as part of registration review for the currently‐registered crops (i.e.,

apples, apricots, Christmas trees, nectarines, containerized plants, peaches, pear, persimmon,

and tree nuts) (USEPA, 2012). In this assessment, the highest EDWC for surface water was 7.59

ppb for acute, 0.062 ppb for a 1‐in‐10 year annual average, and 0.025 ppb for the 30‐year

annual average.  The groundwater concentration was predicted to be no more than 0.04 ppb.  

The Surface Water Concentration Calculator (version 1.106) has since replaced PRZM‐EXAMS

(with the PE5 shell). Because the SWCC modeling results are expected to be comparable to

these modeled using PRZM EXAMS (i.e., similar data files in the model, exposure scenarios
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chosen and input parameters), the previously‐reported surface water values continue to be

representative of modeled surface water concentrations.  

PRZM‐GW is currently used to estimate potential concentrations in source groundwater

(replaced SCI‐GROW).  All scenarios resulted in concentrations lower than that reported of SCI‐

GROW (see Table 2).  

Because the surface water EDWCs continue to be the more conservative values, EFED

recommends that HED use the previously modeled surface water concentrations for the human

health risk assessment (i.e., 7.59 ppb for acute, 0.062 ppb for a 1‐in‐10 year annual average,

and 0.025 ppb for the 30‐year annual average).  

Table 2. Summary of Predicted Groundwater Concentrations of Clofentezine Using PRZM GW

for the Proposed Uses.

Scenario

Identification

Simulation

Years  

(to

breakthrough)

Peak, Post

Breakthrough

Average, and

Annual

Average

(ppb)1

Breakthrough

Time Throughputs

DELMARVA_STD.SCN 30 <0.05 7148.896 1.533104

FLCITRUS_STD.SCN 30 <0.05 5910.043 1.85447

FLPOTATO_STD.SCN2 100 <0.05 1.18E+04 3.055691

GACOASTAL_STD.SCN 30 <0.05 9769.87 1.121816

NCCOASTAL_STD.SCN 30 <0.05 6728.034 1.629005

WISANDS_STD_1.SCN 30 <0.05 9301.117 1.178353

1 All predicted concentrations are well below the quantitative level of detection, which is the reported

value here.

2 Results for a 100‐year simulation are presented here because breakthrough was not achieved in this

scenario based on a 30‐year simulation.

Reference:

U.S. EPA. 2012. Clofentezine Drinking Water Assessment for Application to Almonds, Apples,

Apricots, Christmas Trees, Nectarines, Containerized Plants, Peaches, Pears, Persimmons,

Pecans, and Walnuts. Environmental Fate and Effects Division. DP 404287, August 3, 2012.