resulting from pesticide interaction with soil microor ganisms in aerobic (oxygen

- rich) conditions in the laboratory. The fate of pendimethalin formed in or deposited on soil cannot be characterized without the requested data. The Agency is asking for a minimum environmental fate data set for the pendimethali n in order to estimate aquatic and terrestrial exposure. Without these data, exposure estimates will be based on conservative assumptions.
2. Environmental Chemistry Methods and Associated Independent Laboratory Validation (soil and water) (850.6100) : Inde pendently validated analytical methods for residues in water, sediment, and soil (environmental chemistry methods) submitted by the registrant are used to evaluate analyses described in submitted environmental fate and ecological
effects studies. Submitte d analytical methods are also used by various Federal, State, Tribal, and local agencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent laboratory valid ations for submitted analytical methods are necessary to confirm that the methods are functional and to confirm the levels of detection and quantitation reported in registrant

- prepared validations (MRIDs 45364705, 45364706, 45163802, and 45136801)

.

The av ailable effects data are considered incomplete for the purposes of risk assessment. The following data gaps exist:

1. Avian acute oral toxicity (OCSPP guideline # 850.2100). Avian acute oral toxicity data are not available for passerines, which are required under the new 40 CFR Part 158.

2. Whole sediment chronic invertebrates (in prep OCSPP guideline #s 850.1760, 850.1770, and 850.1780) 1 . No acceptable chronic or sediment toxicity tests for freshwater or
marine invertebrates have been submitted for pendimethalin to satisfy the Agency’s updated data requirements for outdoor uses in 40 CFR Part 158 (October 26, 2007). Chronic whole sediment tests on Hyalella azteca, Chironomus tentans, and Leptocheirus plumulosus are requested.

3. Saltwater Aquatic Inv ertebrate Life Cycle (OCSPP guideline # 850.1350). No chronic invertebrate tests for marine invertebrates have been submitted for pendimethalin to satisfy the Agency’s data requirements for outdoor uses in 40 CFR Part 158). A chronic life cycle study on a saltwater invertebrate is requested.

1 As an alternative to recommending the conduct of 2 chronic (life cycle) sediment toxicity tests, EFED would also

consider a tiere d testing approach for sediment toxicity testing. In this approach, sediment toxicity testing would first be conducted with the aforementioned species using the 10

- d (subchronic) sediment toxicity test guidelines (OSCPP 850.1735 and 850.1740). Then, pend ing a comparison of estimated environmental concentrations (EEC) in sediment and porewater with toxicity results from the 10

- d sediment toxicity studies, the need for one or more chronic sediment toxicity studies would be determined. This tiered testing a pproach has the potential advantage of reducing the number of chronic (life cycle) studies that would be needed when results of the 10

- d (subchronic) tests in conjunction with sediment EECs indicate chronic testing is not likely to alter risk assessment co nclusions. In some cases, however, this tiered testing approach may result in the conduct of both a 10

- d (subchronic) and a chronic (life cycle) study.4. Saltwater Fish Early

- Life Cycle (OCSPP guideline # 850.1400). No chronic fish tests for marine invertebrates have been submitted for pendimethalin to satisfy the Agency’s data requirements for outdoor uses in 40 CF R Part 158). A chronic life cycle study on a saltwater fish is requested.

5. Vegetative vigor and seedling emergence (OSCPP guideline #s 850.4150 and 850.4250). No acceptable toxicity data are currently available to assess the risk of pendimethalin to

non

- target terrestrial plants. Since pendimethalin has many outdoor uses, vegetative vigor and seedling emergence studies are needed

. In addition, four minor terrestrial plant incidents have been reported to the Agency involving pendimethalin . Phytotoxicity data are needed to assess the impact of pendimethalin on non

- target terrestrial plants.

6. Aquatic plant growth (OSCPP quidline #s 850.4400 and 850.5400). No acceptable toxicity data are currently available to assess the risk of pendimethalin to non

- target aquatic nonvascular and vascular plants. Since pendimethalin has many outdoor uses, aquatic plant growth toxicity studies are requested with either cypermethrin technical or a typical end

- use product.

Additional detail on the current data gaps for enviro nmental fate and effect s is provided in
Section 7.9.

# Problem Formulation for the Environmental Fate and Ecological Risk, Endangered Species, and Drinking

Water Assessments in Support of the Registration
Review of Pendimethalin

N

- (1

- ethylpropyl)

- 3,4

- dimethyl

- 2,6

- dinitrobenzenamine CAS Registry Number: 40487

- 42

- 1
PC Code: 108501

Prepared by: Elizabeth Riley, Biologist

Ibrahim Abdel

- Saheb

, Ph.D, Environmental Scientist U. S. Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division
Environmental Risk Branch VI 1200 Pennsylvania Ave., NW
Mail Code 7507P Washington, DC 20460 Reviewed by: William P. Eckel, Senior Scientist Stephen Carey, Biologist

August 30 , 2012 

### Office of Chemical Safety
and Pollution Prevention2 Table of Contents

1 PURPOSE

................................ ................................ ................................ ................................ ...................... 3

2 PROBLEM FORMULATION

................................ ................................ ................................ ............................. 3

2.1 N ATURE OF R EGULATORY A CTION

................................ ................................ ................................ ........................... 3

2.2 P REVIOUS R ISK A SSESSMENTS

................................ ................................ ................................ ................................ . 3

3 STRUCTURE AND PHYSIC AL/CHEMICAL PROPERTI ES OF PARENT

................................ ................................ .. 6

3.1 O VERVIEW OF P ESTICDE U SAGE

................................ ................................ ................................ .............................. 7

3. 2 E NVIRONMENTAL F ATE AND T RANSPORT

................................ ................................ ................................ ................ 12

4 RECEPTORS

................................ ................................ ................................ ................................ ................. 17

4.1 A QUATIC AND T ERRESTRIAL E FFECTS

................................ ................................ ................................ ...................... 17

4.1.1 Terrestrial Animals

................................ ................................ ................................ ............................... 17

4.1.2 Aquatic Animals

................................ ................................ ................................ ................................ ... 19

4.1.3 Plan ts

................................ ................................ ................................ ................................ ................... 22

4.2 I NCIDENT D ATABASE R EVIEW

................................ ................................ ................................ ................................ 23

4.3 E COSYSTEMS P OTENTIALLY AT R ISK

................................ ................................ ................................ ........................ 25

5 ASSESSMENT ENDPOINTS

................................ ................................ ................................ ........................... 25

6 CONCEPTUAL MODEL

................................ ................................ ................................ ................................ . 26

6.1 R ISK H YPOTHESIS

................................ ................................ ................................ ................................ ............... 26

6.2 C ONCEPTUAL D IAGRAM

................................ ................................ ................................ ................................ ....... 27

7 ANALYSIS PLAN

................................ ................................ ................................ ................................ ........... 30

7.1 S TRESSORS OF C ONCERN

................................ ................................ ................................ ................................ ...... 31

7.2 M EASURES OF E XPOSURE

................................ ................................ ................................ ................................ ..... 31

7.3 M EAS URES OF E FFECT

................................ ................................ ................................ ................................ ......... 35

7.4 I NTEGRATION OF E XPOSURE AND E FFECTS

................................ ................................ ................................ ............... 36

7.5 D ETERMINISTIC AND P ROBABILISTIC A SSESSMENT M ETHODS

................................ ................................ ...................... 36

7.6 E NDANGERED S PECIES A SSESSMENTS

................................ ................................ ................................ ..................... 36

7.7 D RINKING W ATER A SSESSMENT

................................ ................................ ................................ ............................ 37

7.8 E NDOCRINE D ISRUPTOR S CREENING P ROGRAM

................................ ................................ ................................ ........ 37

7.9 P RELIMINARY I DENTIFICATION OF D ATA G APS

................................ ................................ ................................ .......... 38

7.9.1 Environmental Fate Data Gaps

................................ ................................ ................................ ............ 38

7.9.2 Effects

................................ ................................ ................................ ................................ .................. 39

8 LITERATURE CITED

................................ ................................ ................................ ................................ ...... 45

9 FATE AND ECOTOXICITY BIBLIOGR APHY

................................ ................................ ................................ ..... 46

APPENDIX A. PRD DA TA REQUEST JUSTIFICA TION TABLES

................................ ........................... 59

APPENDIX B. REPORTED PENDIMETHAL IN ECOLOGICAL INCIDE NT SUMMARIES IN THE EIIS
DATABASE

................................ ................................ ................................ ................................ ....................... 633 1 Purpose

The purpose of this problem formulation is to provide the fou ndation for the ecological risk assessment being conducted for the registered uses of pendimethalin . As such, it articulates the purpose and objectives of the risk assessment, evaluates the nature of the problem, and provides a plan for analyzing the data and characterizing the risk (USEPA, 1998). Additionally, this problem formulation is intended to identify data g aps, uncertainties

, and potential assumptions needed to address those uncertainties in characterizing the ecological risk associated with the registered uses of pendimethalin

.

2 Problem Formulation

2.1 Nature of Regulatory Action

This report is the Environm ental Fate and Effects Division’s (EFED) Problem Formulation for the Registration Review of pendimethalin . Previous risk assessments wer e completed for the use
of this chemical , which serve as the basis for this document.

The Food Quality Protection Act (FQPA) of 1996 mandated the EPA to implement registration review ( http://www.epa.gov/oppsrrd1/registration_review/ ). All pesticides distributed or sold in the United States generally must be registered by the EPA. The decision to register a pesticide is based on the consideration of scientific data and other factors showing that it will not cause
unreasonable risks to human health, workers, or the environment when used as directed on product labeling. In addition, it must not be expected to cause unreasonable adverse effects to human health through the dietary and residential routes of exposure under the Federal Foo d Drug and Cosmetic Act (FFDCA). The registration review program is intended to ensure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to meet the statutory standard of no unreasonable a dverse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the registration review program, the Agency periodically reevaluates pesticides to make sure that as change o ccurs, products in the marketplace can be used safely.

As part of the implementation of the Registration Review program pursuant to Section 3(g) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is conducting an
evaluation to determine whether pendimethalin continue s to meet the FIFRA standard for registration. This problem formulation for the environmental fate and ecological risk assessment chapter, in support of the registration review, is intended for the initial docket op ening the public phase of the review process.

2.2 Previous Risk Assessments

Pendimethalin was patented by American Cyanamid in 1972 and first registered in the United
States in 1974. Pendimethalin is a dinitroaniline herbicide which selectively controls ce rtain broadleaf weeds and grassy weed species in certain crop and non

- crop areas. It is applied to soil

pre

- plant, pre

- emergence, and post

- emergence, with ground and aerial equipment. The Reregistration Eligibility Decision Document [RED], published in J une 1997, concluded that uses of pendimethalin would not cause unreasonable risks to the environment, though risks
were identified for listed and non

- listed fish and aquatic invertebrates as well as terrestrial and aquatic plants and listed and non

- listed birds and mammals.4 Pendimethalin is currently registered for use on a variety of agricultural crops, turf, and
ornamentals . It can be broadcasted by air or ground and/or be banded as a directed spray or applied via irrigation equipment. Currently regis tered maximum single application rates of pendimethalin range from approximately 1 to 6 lb a.i./A with a seasonal application rates range
from 4 to 6 lbai/A . Recent pendimethalin ecological risk assessments include the litigation

related California red

- le gged frog (CRLF) assessment (USEPA, 2009) a Section 3 new use assessment for artichoke, asparagus, brassica subgroup 5a, and grapes (USEPA, 2007; DP 334069) and a Section 3 new use assessment for edamame and cold

- and warm

- weather forage grass (USEPA, 2010 ; DP 378514).

The most recent review per formed for pendimethalin was the Section 3 New Use registration for use on leaf lettuce, brassica leafy greens subgroup 5B, turnip greens, melon subgroup 9A, succulent soybean (edamame) and small fruit vine climbi ng subgroup 13

- 07E except grapes (DP
391166 and DP 391167 , March 20012 )

. The screening

- level risk assessment indicated that pendimethalin on these crops ha s the potential for direct acute effects to listed freshwater fish, estuarine/marine fish, estuarine /marine invertebrates , and aquatic vascular and non

- vascular plants (including risk to non

- listed aquatic non

- vascular plants). With respect to terrestrial animals, direct acute and chronic effects to listed and non

- listed birds and mammals are possible. In addition, acute and chronic effects to piscivorous birds and mammals via ingestion of pendimethalin residues in aquatic biota may be possible; however, depuration of pendimethalin

was observed in the submitted blue gill sunfish study , which may reduce the potential for
bioaccumulation . Risks to terrestrial plants are also predicted.

National Water Quality Assessment (NAWQA)
Pendimethalin is included in the NAWQA sampling and analysis program ( http://infotrek.er.usgs.gov/apex/f?p=136:23:0:QUERY:NO:::

, accessed 4/05/2012 ). It was
measured in 21.28 % of water samples as “code 82683

, Pendimethalin _ water_ filtered_ (0.7 micron glass fiber filter)_recoverable_micrograms per liter ” and 0.7% of water samples as “code 61665, 4

- (Hydroxymethyl) pendimethalin_wa ter_filtered_recoverable_micrograms per liter”. Pendimethalin was measured, with detection limits ranging from 0.004 to 0.022 ppb , in all 50

states. Table 3 .1 below gives the toal number of samples analyzed for water and the total number of pendimethalin detects in each state.5 Table 3 .1. Number of NAWQA Water Samples analyzed for Pendimethalin and number of detects 1

State No. of Water
Samples No. of Detects State No. of Water
Samples No. of Detects

AL 419 95 MO 209 13

AK 39 0 MT 94 1

AZ 229 35 NE > 500 141

AR 118 3 NV 318 25

CA >500 >500 NH 82 0

CO >500 128 NJ >500 60

CT 214 3 NM 190 2

DE 87 0 NY 394 45

DC 4 1 NC 401 45

FL 419 4 ND 74 1

GA >500 128 OH 316 50

HI 56 1 OK 62 1

ID 380 3 OR 303 104

IL 449 104 PA >500 127

IN 430 122 RI 12 0

IA 407 36 SC 306 8

KS 180 1 SD 5 0

KY 13 1 TN 347 27

LA 388 74 TX >500 184

ME 77 0 UT 336 49

MD 293 48 VT 39 0

MA 219 12 VA 390 68

MI 232 14 WA >500 82

MN 430 15 WV 101 0

MS 187 89 WI 395 43

WY 99 1

1 Detection limits range from 0.004 to 0.022 ppb.

Aquatic Life Criteria and Aquatic Life Benchmarks The Clean Water Act requires the Agency to publish water quality criteria that accurately reflect the latest scientific knowledge on the kind and extent of all identifiable effects on health and
welf are which might be expected from the presence of pollutants in any body of water, including ground water. While these recommended criteria do not, in themselves, impose any requirements, states and authorized tribes can use them to develop water quality st andards. The US EPA Aquatic Life Ambient Water Quality Criteria document may be found at http://www.epa.gov/waterscience/criteria/ (accessed 4/09/12 ). No criteria for pendimethalin have been published.

Impaired Water Bodies
Pendimethalin is not identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act 1 . In addition, no Total Maximum Daily Loads

1 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=8856 (TMDL) have been developed for Pendimethalin 2 . More information on impaired water bodies and TMDLs can be found at the Agency’s website 3 . The Agency invites submission of water quality data for this pesticide. To the extent possible, data should conform to the qual ity standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management Process 4 in order to ensure they can be used quantitatively or qu alitatively in pesticide risk assessments.

For pendimethalin , OPP has published aquatic life benchmarks for freshwater species, based on the most sensitive species from the most recent risk assessments (refer to the following site http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm#benchmarks accessed

4 / 09/12 ). The benchmarks are 69 ppb (fish acute), 6.3 ppb (fish chronic), 140 ppb (invertebr ate acute), 14.5 ppb (invertebrate chronic) , 5.2 ppb (non

- vascular plant acute), and 12.5 ppb (vascular plant acute)

.

3 Structure and Physical/Chemical Properties of Parent

Table 4 .1 provides some identification information for pendimethalin . The general structure of pendimethalin is provided in Figures 4

- 1

.

Figure 4

- 1. The general structure of pendimethalin

Table 4 .2 lists various important physicochemical characteristics of pendimethalin

.

2 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_group_name=PEST ICIDES

3 http://www.epa.gov/owow/tmdl/

4 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm

.7 TABLE 4

. 2

. General Chemical Properties

Fate Property Value (unit) MRID (or source)

Trade and Other Names Prowl, Squadron 1997 RED

CAS Registry Number: 40487

- 42

- 1 1997 RED

Empirical Formula C 13 H 19 N 3 O 4 1997 RED

Molecular Weight 281.31 Foot Print Pesticide
Database @http://sitem.herts.ac. uk/aeru/footprint/en/in
dex.htm

Henry’s constant (atm

- m3/mol) 4.04x 10
- 5 calculated

Vapor Pressure (mmHg) 3.0x10
- 5 MRID# 00153766

Water Solubility (mg/L.) 0.275 MRID#46861302

Octanol

- water partition coefficient (Log

K OW ) pH 7, 20 o C 152, 000 (5.18) Foot Print Pesticide
Database @http://sitem.herts.ac.uk /aeru/footprint/en/index.h

tm

Dissociation Constant (pKa) at 25 o C 2.8 Foot Print Pesticide
Database @http://sitem.herts.ac.uk /aeru/footprint/en/index.h

tm Chemical Family Dinitroaniline 1997 RED

SMILES Code [O

- ][N+](=O)c1c(c(cc([N+]([O

- ])=O)c1NC(CC)CC)C)C Foot Print Pesticide
Database @http://sitem.herts.ac.uk /aeru/footprint/en/index.h

tm

Mode of Action of Herbicide

Pendimethalin is a selective herbicide registered for control of broadleaf weeds and grassy weed species on a variety of agricultural crops, turf, and ornamentals. Pendimethalin disrupts the process of mitosis in the growth of shoots and roots. It acts as a microtubule disruptor by inhibiting cell division and cell elongation in plants, and is generally applied early in the growing season. Adsorption of the herbicide takes place at the roots and shoots. Very little translocation
occurs from the site of intake.

3.1 Overview of Pesticde Usage

Pendimethalin i s applied as a liquid spray formulation. Pendimethalin can be applied either by aerial equipment or using ground equipment to a variety of agricultural and non

- agricultural
sites. It can be broadcasted by air or ground, and be banded as a directed spray or applied by irrigation equipment in various crops. It can also be left on the soil surface or incorporated. The use information presented in this problem formulation was obtained from the tables in the EFED Label Data Report dated 5/31/2012 , from BEAD’ s Chemical Profile for Registration Review8 (USEPA 2012 ), and from various evaluated labels. There are currently 8 3 Section 3 registered products as well as 20 Special Local Needs (SLN) registrations for pendimethalin.

Pendimethalin has numerous uses. A summary of agricultural use patterns based on maximum application rate per crop group for pendimethalin is shown Table 4 .3

.

Table 4 .3. Summary of Agricultural Use Information for the Pendimethalin

Use Maximum Applic. Rate Maximum
Seasonal Rate Maximum
Number of Applications Minimum
Retreatment
Interval

(days)

Citrus 6.00 lb a.i./A 6.00 lb a.i./A NS 30 Nut crops 6.00 lb a.i./A 6.00 lb a.i./A NS 30

Pome fruits 4.00 lb a.i./A 6.00 lb a.i./A NS NS

Stone fruits 4.00 lb a.i./A 4.00 lb a.i./A NS 30 Flavoring and spice crops 2.00 lb a.i./A 2.00 lb a.i./A NS NS Fruiting vegetables 1.50 lb a.i./A 1.50 lb a.i./A NS NS Leafy and stem vegetables 4.00 lb a.i./A 4.00 lb a.i./A 1 NS

Root crop vegetables 1.50 lb a.i./A NS NS NS Forage grasses 4.00 lb a.i./A 4.00 lb a.i/A NS NS Legumes 1.50 lb a.i./A NS NS NS Grain crops 1.50 lb a.i./A 1.50 lb a.i./A NS NS Sugarcane 4.00 lb a.i/A 6.00 lb a.i./A NS NS

Tobacco 1.50 lb a.i./A NS NS NS

Corn 2.00 lb a.i./A 2.00 lb a.i./A NS NS

Cotton 2.00 lb a.i./A NS NS NS

Olives 4.00 lb a.i./A 4.00 lb a.i/A NS 30

Peanuts 1.70 lb a.i./A NS NS NS

Sunflowers 1.50 lb a.i./A NS NS NS Soybeans 2.00 lb a.i./A 2.00 lb a.i./A NS NS Asparagus 4.00 lb a.i/A 4.00 lb a.i./A NS NS

Onions 1.89 lb a.i./A 5.92 lb a.i./A NS NS

Rice 1.00 lb a.i./A NS NS NS Grapes 6.00 lb a.i./A 6.00 lb a.i./A NS 30

Strawberries 1.50 lb a.i./A 3.00 lb a.i./A NS NS Figs 4.41 lb a.i./A NS NS NA Loquat 4.00 lb a.i./A 4.00 lb a.i/A NS NS Pomegranates 4.00 lb a.i./A 4.00 lb a.i/A NS 30

The agricultural usage of pendimethalin , from the Screening Level Usage Analysis (SLUA), is provided in Table 4

. 4 . The table is arranged by crop in alphabetical order. According to the table, the major agricultural use s for pendimethalin are soybean (2.6 million lbs a.i. annually),

cotton (1.7 million lbs a.i. annually) and corn (1.5 million lbs a.i. annually)

.

Table 4 .4. Screening

- Level Estimates of Agricultural Uses of Pendimethalin (SLUA) 5
Percent Crop Ttd.

Crop Lbs. A.I. Avg. Max.

1 Alfalfa 100,000 <1 <2.5

5 Dated 01/21/20119 2 Almonds 500,000 20 45

3 Apples 40,000 5 20

4 Apricots 3,000 10 25

5 Asparagus 1,000 <2.5 5

6 Beans, Green 30,000 15 25

7 Cabbage 2,000 5 15

8 Caneberries + 7,000 20 20

9 Cantaloupes + <500 <1 <2.5

10 Carrots 20,000 20 60

11 Cherries 40,000 10 35

12 Corn 1,500,000 <2.5 5

13 Cotton 1,700,000 15 20

14 Cucumbers + 2,000 <2.5 5

15 Dry Beans/Peas 300,000 15 20

16 Fallow 10,000 <1 <2.5

17 Garlic 20,000 75 100

18 Grapefruit 20,000 10 20

19 Grapes 200,000 5 30

20 Hazelnuts, Filberts 5,000 5 15

21 Lemons 5,000 5 5

22 Lima beans 10,000 40 50

23 Nectarines 5,000 10 10

24 Onions 100,000 65 80

25 Oranges 100,000 5 15

26 Pasture 1,000 <1 <2.5

27 Peaches 20,000 5 20

28 Peanuts 500,000 45 60

29 Pears 10,000 5 20

30 Peas, Green 60,000 45 65

31 Pecans 20,000 <2.5 5

32 Peppers 7,000 10 25

33 Pistachios 100,000 25 60

34 Plums/prunes 30,000 10 25

35 Pomegranates* 30,000 N/C N/C

36 Potatoes 200,000 30 35

37 Pumpkins + 1,000 <2.5 5

38 Rice 100,000 5 10

39 Sorghum 6,000 <1 <2.5

40 Soybeans 2,600,000 5 10

41 Squash + <500 <2.5 <2.5

42 Strawberries 1,000 <2.5 5

43 Sugarcane 600,000 30 4510 44 Sunflowers 400,000 15 25

45 Sweet Corn 50,000 10 15

46 Tangerine 4,000 5 5

47 Tobacco 100,000 40 45

48 Tomatoes 50,000 15 30

49 Walnuts 80,000 10 25

50 Watermelons + 5,000 5 10

51 Wheat 7,000 <1 <2.5 Sorted alphabetically. All numbers rounded. <500 Less than 500 pounds of active ingredient <2.5 Less than 2.5 percent of crop treated <1 Less than 1 percent of crop treated N/C Only Lbs. A.I. available * CA data only (95% or more of U.S. acres in California)

SLUA data sources include:
USDA

- NASS (United States Department of Agriculture's National Agricultural Statistics Service) (pesticide usage data from 2001 t o 2008) Private Pesticide Market Research (pesticide usage data from 2001 to 2008) California DPR (Department of Pesticide Regulation) (data for 2000 to 2008)

BEAD provided agricultural information by state in its Pendimethalin Chemical Profile for Registration Review (USEPA 2012 ) . The BEAD report states: “ The states with the most agricultural usage in terms of pounds AI applied are California (19%), Texas (8%), Georgia (8%), Iowa (6%), Illinois (5%), and Louisiana (5%). In term s of total area treated the top states are Texas (11%), Georgia (10%), California (9%), Iowa (7%) and Illinois (5%).” Figure 4

- 2 show s the 2006

- 2010 estimated annual agricultural use of pendimethalin from the BEAD report.11 Figure 4

- 2. Pendimethalin Usage by Crop Reporting District (2006

- 2010). 6

The following labeling statements appear on all pendimethalin labels to avoid contamination of aquatic environments and endangered species from use on agricultural products.

ENVIRONMENTAL HAZARD STATEMENTS

• Thi s product is toxic to fish. DO NOT apply directly to water, or to areas where surface water is present, or to intertidal areas below the mean high water mark.

6 This is a map of agricultural pesticide usage at the Crop Reporting District (CRD) level. CRDs are boundaries created by USDA NASS which are aggregates of counties (USDA, 2010). Pesticide usage is displayed as average pounds (for the years 2006

- 2010) per 1,000 acres of farmland in a CRD to normalize for the variation in farmland between CRDs. Farmland acreage was obtained from USDA (2007). Usage is based on private market surveys of pesticide use in agriculture (Proprietary Data, 2006

- 2010). The survey data are limited t o the states that represent the top 80

- 90% of acreage for the individual crops

, therefore, use may be occurring in regions outside the scope of the survey. CRDs showing no usage of pesticides may be due to either the lack of pesticide use in the region or non

participation in the agricultural surveys. In addition, across the years, there may be variations in the specific crops included in the CRD survey. This may result in a lower annual average for

- the CRD.
Sources: Proprietary Data. 2006

- 2010

. USDA, 2006

- 2010. NASS Crop Reporting Districts. Online : http://www.ers.usda.govlbriefing/arms / resourceregions / resourceregions.htm#nass

. USDA,2007

. Census of Agriculture. Online : http: // www.agcensus.usda.gov/Publications / 2007 Ii ndex.asp

.12 • Drift and runoff from treated areas may be hazardous to aquatic organisms in adjacent aquatic areas. DO NOT contaminate water when disposing of equipment washwateres or
rinsate.

ENDANGERED SPECIES PROTECTION

• If endangered plant species occur in proximity to the application sites, the following mitigations are required:

o If applied by ground, leave an untreated buffer zone of 200 feet. The product must be applied using low boom (20 inches above the ground) and ASAE fine to
medium/coarse nozzles.

o If applied by air, leave an untreated buffer zone of 170 feet. Must use straight

stream nozzles (D

- 6 or larger): wind can be no more than 8 mph, and release height must be 15 feet or less.

In addition to the agricultural uses described above , pendimethalin has num erous non

agriculatural uses ( Table 4.5 ).

Table 4

. 5 . Summary of Non

- Agricultural Use Information for the Pendimethalin

Use Maximum Applic. Rate Maximum
Seasonal Rate Maximum
Number of Applications Minimum
Retreatment
Interval

(days)

Ornamental nurseries 4.41 lb a.i./A NS NS NS

Christmas tree plantations 4.41 lb a.i./A NS NS NS

Sod farms 3.50 lb a.i./A NS NS NS Rangeland 3.50 lb a.i./A NS NS NS Forestry 4.40 lbs a.i./A NS NS NS

Commercial/ industrial/
recreational lawns 3.96 lb a.i./A NS NS NS

Golf courses 3.50 lb a.i./A NS NS NS Airports/ landing fields 3.50 lb a.i./A NS NS NS

Uncultivated agriculatural areas (fallow land) 3.00 lbs a.i/A 3.00 lbs a.i./A 1 NA

Rights

- of

- way/ fencerows/ hedgerows 4.41 lb a.i./A NS NS NS

Around commercial, industrial, institutional buildings 4.32 lb a.i./A NS NS NS

Around paved areas 4.41 lb a.i./A NS NS NS

Residential lawns 3.96 lb a.i./A NS NS NS

3.2 Environmental Fate and Transport

Table 4

. 6 summarizes the environmental fate/transport properties of pendimethalin

.

Table 4

. 6

. Environmental fate/transport properties of pendimethalin

Study Value (units) Major Degradates Minor Degradates MRID #13 Hydrolysis Stable None 00106777

Direct Aqueous Photolysis Dark corrected, continuous
irradiation half

- life 21 days; 12

- hour light/dark half

- life 42 days. 37 minor, unidentified degradates 2,6

- dinitro

- 3,4

- dimethylaniline (9.3% of applied) 00153763
43808201

Soil Photolysis Stable None 00153764

Aerobic Soil
Metabolism 1322 days (log linear calculations) 2,6

- dinitro3,4

- xylidine 4

- [(1

- ethylpropyl)amino]

- 2

- methyl

- 3,5

- dinitrobenzyl
alcohol 4

- [(1

- ethylpropyl)amino]

- 2

- methyl

- 3,5

- dinitro

- o

- toluic
acid 40185104

Anaerobic Soil
Metabolism Stable 98% parent at 60 days 2,6

- dinitro3,4

- xylidine 4

- [(1

- ethylpropyl)amino]

- 2

- methyl

- 3,5

- dinitrobenzyl
alcohol 4

- [(1

- ethylpropyl)amino]

- 2

- methyl3,5

- dinitro

- o

- toluic
acid 40185105

Anaerobic Aquatic
Metabolism 68

- day half

- life (upper 90 th %ile confidence bound on mean) None 40813501
43154702

Aerobic Aquatic
Metabolism 27 X 3 (81 days) None 47385201

K d

- ads / K d

- des (mL/g)

K oc

- ads / K oc

- des (mL/g) 30

– 854 (U.S. soils) 61

– 285 (Japanese soils)

17,040 mL/g O.C. (U.S. soils) (avg of 5 values, 13000

– 29400)
7011

- 43863 mL/g o.c. (Japanese soils) N/A 00153765
43041901

Laboratory Volatility Volatilization half

- life 12.5 days
from moist loam soil None measured
00153766

Fish
Bioaccumulation Bioconcentration factor BCF = 5100, 35

- day exposure 4

- [(1

- ethylpropyl)amino]

- 2

- methyl

- 3,5

- dinitrobenzyl alcohol (3.1%) 00156726
00158235

Degradation

Available structures of observed degradates are provided in Table 4

. 7

. The alcohol metabolites 3, 4, 5, and 7 are isomers and the acid metabolit e s 2 and 6 are isomers. Thus there are 3 g r oups of degradates; alcohols, acids and 2,6

- dinitro

- 3,4

- dimethylaniline (metabolite # 1). These degradates are considered minor.

Table 4

. 7

. Chemical names and stru ctures of pendimethalin metabolites

Number Structure Name14 1 2,6

- Dinitro

- 3,4

- dimethylaniline

2
acid N

- (1

- Ethylpropyl)

- 3,4

- dimethyl

- 2,6

- dinitroaniline

3
alcohol (4

- [(1

- Ethylpropyl)amino]

- 2

- methyl

- 3,5

- dinitrophenyl)methanol

4
alcohol 3,5

- Dinitrobenzyl alcohol
metabolite

5
alcohol 2,4

- Dinitrobenzyl alcohol
metabolite

6
acid 4

- [(l

- ethylpropy1)aminol

- 3,5

- dinitro

- o

- touc acid15 7
alcohol 4

- [(1

- ethyl

- propyl)amino]

- 2

- methyl

- 3,5

- dinitro benzyl
alcohol

To explore the potential toxicity of the metabolites of pendimethalin to aquatic animals and plants , EFED employed t he Ecological Structure Activity Relationships (Ecosar v1.0) program

. Based on the structure of the parent compound, Ecosar predict s a degradate’s aquatic toxicity based on structural classes it belongs to

. These toxicity values can then be compared to the available aquatic toxicity data for the parent chemical of interest in order to identify potential degr a dates of concern

. Degradates that are predicted to have e qual or greater toxic ity than the parent may be of concern for risk assessment and may require additional data or inclusion in a Total Toxic Residue (TTR) approach if they occur in significant amounts in the environment to present a risk concern

.

Ecosar placed the parent compound pendimethalin in the dinitrobenzene class, with toxicity to aquatic organisms as the available data indicates for pendimethalin ( Table 4

. 8 )

. The prediction for pendimethalin matched the actual data very well, thus the dinitrobenzene class QSAR was used for degradates that Ecosar also identified as dinitrobenzenes

. Ecosar automatically assumes that metabolites with an acid group are ten times le ss toxic. For the purposes of this comparison

, th e 10x adjustment factor for the acid group being present was removed. Based on this comparison; 1) the alcohol metabolites have equal or greater toxicity to pendimethalin for chronic freshwater fish, acute freshwater invertebrates, acute and chronic estuarine/marine fish, and acute green algae; and 2) the acid metabolites and the dinitromethylamine metabolites all have lesser toxicity than the parent pendimethalin

.

Table 4

. 8

. Ecosar v1.0 Analysis of Pendim ethalin and its Degradates Endpoint Parent
data (ppm) QSAR

(ppm) 3/4/5/7

ecosar 1 (ppm) 2/6 ecosar 2
(ppm) 1 ecosar 3

(ppm) QSAR
class -- Dinitrobenzen es (dnb) dnb Dnb

- acid Dinitroaro

matic amine

FW fish

acute 0.138 0.125 1.167 6.202 6.877

FW fish
chronic 0.0063 0.004 0.018 * 0.119 0.661

Daphnia

acute 0.280 0.697 7.746 38.971 5.049

Daphnia
chronic 0.0145 0.020 0.120 0.733 0.529

Green algae No data 0.209 0.495 * 4.034 23.495 (neutral16 acute organic QSAR)
SW fish

acute 0.710 0.618 1.732 * No prediction No prediction

SW fish
chronic No data 0.053 0.162 * No prediction No prediction

1 Degradates 3, 4, 5, and 7 are alcohol metabolites

2 Degradates 2 and 6 are acid metabolites

3 Degradate 1 is a dinitrodimethylaimine metabolite Values with an asterisk (*) indicate degradates that are within a factor of 3 of parent toxicity (actual data or QSAR) and may be in included as part of the Total Toxic Residue (TTR ) . Values for the acid metabolites (dnb

- acid 2 and 6) presented have had th e 10x adjustment factor for the acid group being present
removed.

Fate in the Terrestrial Environment

Pendimethalin dissipates in the environment by sorption to soil, metaboliz ation by microbes, and by volatiliz at i on into air. Microbes can degrade pendimethalin to many non

- significant ( < l0 %
of applied radio activity ) degradates. Also, the volatilization can be significant because pendimethalin has very limited water solubility, relatively high vapor pressure, and a high log

K
ow . Persistence in the terrestrial environment will decrease with increasing temperature, moisture, or decreasing soil organic carbon because the extent of sorption of pendimethalin is related to soil organic content. Pendimethalin residues in field studies are tightly boun d to soil and sediment particles, which is consistent with the laboratory mobility studies.

Pendimethalin degraded in one soil and under aerobic soil conditions with a half

- life of 1322 days. Terrestrial field dissipation data that are consistent with la boratory data have also been provided. In an Indiana field dissipation study, the half

- lives ranged from 84

- 147 days. However, in field dissipation studies in Louisiana (LA) and Mississippi (MS), the half

- lives ranged from 4 to 82 days, with most studies containing half

- lives of <20 days. The difference in
half

- lives between LA/MS and Indiana can be attributed to the soil and climatic differences
between the two locations. No leaching was observed in the field dissipation studies, which is
consistent wit h the results of laboratory studies.

Pendimethalin has been detected in air, rain

, and snow, according to a compilation of studies by Majewski and Capel (1995). Pendimethalin was analyzed in at least ten sites, with detection values of 100 to 1,500 ng/L (rain), 0.64 to 3.6 mg/m3 (air), and 1,370 to 3,620 ng/L (fog).

Fate in the Aquatic Environment

Pendimethalin is stable to sterile hydrolysis, soil photolysis, and anaerobic soil metabolism but degrades slowly by aqueous photolysis with a calculated half

- life of 17 days. Pendimethalin is stable to sterile hydrolysis, but degrades slowly due to anaerobic aquatic
metabolism with a half

- li fe of 68 days (upper 90 percent ile confidence bound on mean) and

, due to aqueous photolysis

, with a calculated half

- life of 17 days. Aqueous residues of parent pendimethalin and its degradates bind to sediment in anaerobic aquatic metabolism and soil mobility studies. Pendimethalin degraded under aerobic aquatic conditions (MRID 47385201)
with a half

- life of 27 days.17 The half

- life in the aquatic field dissipation study 

### (MRID 44527601) was 15 days, and virtually
all residues were present in the top layer of soil once the rice field was flooded.

Pendimethalin accumulated readily in bluegill sunfish with bioconcentrati on factors (BCFs) of 1400X in edible portions, 5800X in non

- edible portions, and 5100X in whole fish. Of labeled

14 C

- pendimethalin taken up by fish, depuration of 87

- 91% of the 14C

- residues occurred by 14 days post exposure.

4 Receptors

4.1 Aquatic and Terrestrial Effects

The receptor is the biological entity that is exposed to the stressor (EPA, 1998). Due to the
outdoor uses of pendimethalin , the types of receptors that may be exposed include both aquatic and terrestrial receptors, such as birds, rep tiles, mammals, amphibians, freshwater and estuarine/marine fish, non

- target terrestrial and aquatic invertebrates and terrestrial and aquatic plants. The stressors in this case are pendimethalin

. Spray drift and runoff exposures are expected for both gr ound and aerial applications of pendimethalin . Consistent with the process described in the Overview Document (USEPA, 2004), this problem formulation uses a surrogate species approach in its evaluation of pendimethalin . Toxicological data generated from surrogate test species, which are intended to be representative of broad taxonomic groups, are used to extrapolate to potential effects on a variety of species (receptors) included under these taxonomic groupings.

T ables 5 .1 and 5 .2 provide a summary of the taxonomic groups and the surrogate species tested to help understand potential acute and chronic ecological effects of pendimethalin to these non

target taxonomic groups.

4.1.1 Terrestrial Animals

A summary of the most sensitive endpoints from the available toxicity studies conducted with terrestrial species is presented in Table 5 .1

.

Table 5 .1 Summary of most sensitive endpoints from submitted terr estrial toxicity studies for pendimethalin

. Species (common

name) Taxa Represented Endpoint Concentration Test
Substance

(% a.i.) Reference/
Classification Acute Toxicity
Classification

Rattus norvegicus (Laboratory Rat) Mammals LD 50 1050 mg a.i./kg

- bw TGAI MRID#

00026657 Acceptable Slightly Toxic

NOAEL 5 2 mg a.i./kg/day
TGAI MRID#

41725203 Acceptable Not Applicable LOAEL 1 25 mg a.i./kg/day

Mallard duck ( Anas platyrhynchos ) Birds,
terrestrial

phase LD 50 1421 mg a.i./kg bw TGAI MRID#

00059739 Acceptable Slightly Toxic18 Table 5 .1 Summary of most sensitive endpoints from submitted terr estrial toxicity studies for pendimethalin

. Species (common

name) Taxa Represented Endpoint Concentration Test
Substance

(% a.i.) Reference/
Classification Acute Toxicity
Classification

Bobwhite quail ( Colinus virginianus ) amphibians, and reptiles
LC 50 4187 mg a.i./kg diet TGAI MRID#

000 59739 Acceptable Practically

non

- toxic

Mallard duck ( Anas platyrhynchos ) NOAEL 141 mg a.i./kg

- diet TGAI MRID#

44907601 Acceptable Not Applicable

LOAEL 1410 mg a.i./kg

- diet TGAI Not Applicable

Apis mellifera

(Honey bee) Terrestrial
invertebrates Contact

L C 50 >49.7 μg a.i./bee TGAI MRID#

0009980 Acceptable Practically

non

- toxic

Mammals

The Agency’s rat acute oral assessment endpoint for risk assessment purpose shows the LD 50 to be 1250 mg/kg (male) and 1050 mg/kg (female) (MRID 00026657). Pendimethalin is considered to be slightly toxic to mammals on an acute oral basis.

A 2

- generation reproduction study (MRID 41725203) with pendimethalin was reviewed by

HED. The parental systemic NOAEL was 25 mg/kg/day (500 ppm), based on decreased body weight gain and food consumption at the LOAEL of 125 mg/kg/day (2500 ppm). The reproductive/offspring NOAEL is 25 mg/kg/day (500 ppm), based on decreases in the numb er of pups born and pup weight at the LOAEL of 125 mg/kg/day (2500 ppm). Parental and reproductive NOAELs and LOAELs were based on a generic ratio (1:20) of dietary intake of
chemical.

The HED Cancer Peer Review Committee classified pendimethalin as a “ Group C” (possible human) carcinogen, based on thyroid follicular cell adenomas in rats. The committee
recommended a non

- quantitative approach (non

- linear, RfD approach) since mode of action studies are available that demonstrate that the thyroid tumors a re due to a thyroid

- pituitary imbalance, and also since pendimethalin was shown to be non

- mutagenic in mammalian somatic cells and germ cells.

Birds

Two sub

- acute LC 50 dietary avian studies and one acute LD 50 oral acute avian study using the technical pendimethalin were submitted to the Agency. For the LC 50 dietary studies, the LC 50 for the bobwhite quail is 4187 ppm and the mallard duck is >4640 ppm. For the acute LD 50 for the mallard, the LD 50 is 1421 mg/k g

- bw.

The endpoint selected for the assessment is the bobwhite quail’s LC 50 of 4187 ppm (MRID 00026674) and the mallard’s LD 50 of 1421 mg/kg

- bw (00059739).

Pendimethalin technical is categorized as slightly toxic on a subacute dietary and acute oral ba sis
to birds. No avian studies using formulated product have been submitted to the Agency.19 Two avian reproduction studies were submitted to the Agency. No treatment related effects were observed in the bobwhite quail and the LOAEL is greater than 1410 ppm. The mallard duck study (MRID 44907601) showed the parameter of 14

- day survivor bodyweight was reduced at 1410 ppm. The NOAEL for the mallard study is 410 ppm. No other treatment related effects
were observed. This study is classified as acceptable

.

Terrestrial Invertebrates

Only one acute oral bee toxicity study (MRID 00051271 or 00108773 ) was submitte d to the Agency. This study was authored by Dr. Atkins in 1974. The species tested is the honey bee, Apis mellifera. The LD 50 acute oral is greater than 49.8 μg/bee with no mortality observed at the highest tested dose. Pendimethalin is classified as practically non

- toxic to the honey bee.

4.1.2 Aquatic Animals

A summary of the most sensitive endpoints from the available toxicity studies conducted with aquatic animals is presented in Table 5 .2

.

5 .2. Summary of most sensitive endpoints from submitted aquatic toxicity studies for pendimethalin

.

Exposure
Scenario Species Exposure
Duration Toxicity
Reference

Value Effects Reference Toxicity Category

Freshwater Fish

Acute Rainbow

trout
( Oncorhynch

us mykiss ) 96 hours LC 50 = 138 μg a.i./L Mortality MRID 00046291 Acceptable Highly Toxic

Chronic Fathead
minnow
( Pimephales promelas ) 288 days NOAEC = 6.3 μg a.i./L
LOAEC = 9.8 μg ai/L Reduced egg production MRID 00037940 Acceptable NA

Freshwater Invertebrates

Acute Daphnia

magna 96 hours EC 50 = 280 μg a.i./L Mortality MRID 00059738 Acceptable Very Highly
Toxic

Chronic Daphnia

magna 21 days NOAEC = 14.5

μg a.i./L
LOAEC = 17.2 μg ai/L Reduced production of

young MRID 00100504 Supplemental NA

Benthic Organisms

Acute Midge
(Chironomus

riparius) 10 days NOAEC > 203 mg a.i./kg No effects MRID 47891601
Supplemental NA

Estuarine/Marine Fish

Acute Sheepshead
minnow
( Cyprinidon 96 hours LC 50 = 710 μg a.i./L Mortality MRID 00131774 Acceptable Very Highly
Toxic20 5 .2. Summary of most sensitive endpoints from submitted aquatic toxicity studies for pendimethalin

.

Exposure
Scenario Species Exposure
Duration Toxicity
Reference

Value Effects Reference Toxicity Category

variegates )

Chronic No data available

Estuarine/Marine Invertebrates

Acut e Eastern Oyster
Crassostrea

virginica 96 hours LC 50 = 210 μg a.i./L Mortality MRID 00131772
Acceptable Very Highly
Toxic

Chronic No data available

Freshwater Fish

Three acute freshwater studies using technical grade pendimethalin are available ( MRIDs 00037778, 0003778, and 00046291 )

. Species studied include the bluegill sunfish, rainbow trout,
and channel catfish with LC 50 values of 199 ppb, 138 ppb and 418 ppb respectively. In addition, seven acute freshwater studies using formulated product are available (MRIDs 00037927, 00037927, 00037927, 00037927, 00037927, 00037927, and 00131773)

. Species studied include the bluegill sunfish, rainbow trout, and channel catfish and LC 50 values ranged from 520 ppb formulation to 94,400 ppb formulation (220 ppb and 28,747 ppb active ingredient, respectivel y), indicating that the formulated products are less toxic to freshwater fish than the technical grade pendimethalin. The available data suggests that pendimthalin is very highly toxic to freshwater
fish on an acute basis.

One chronic freshwater fish st udy (MRID00037940) was submitted to the Agency. This study is a Fathead minnow (Pimephales promelas ) full life cycle study using technical grade pendimethalin. The 288

- day NOAEC is 6.3 ppb (0.0063 ppm). The NOAEC is based on reduction of egg production. The LOAEC = 9.8 ppb (0.0098 ppm) is based on reduction of egg production. Reduced hatchability was also observed at 22 and 43 ppb.

Estuarine/Marine Fish

There is one study available on the acute toxicity of technical grade pendimethalin and the
formu lation AC 92, 533 to the sheepshead minnow ( Cyprinodon variegatus , MRID 00131774 ; Acceptable). The study reported a 96

- hour LC 50 value of 707 ppb (C.I. 552

- 907 ppb) for technical grade pendimethalin and a 96

- hour LC 50 value of 1700 ppb (C.I. 1230

- 3560 ppb ) for
the formulation.

Chronic data on the toxicity of pendimethalin to estuarine/marine fish are not available . This is identified as a data gap.

Freshwater Invertebrates

Three acute freshwater invertebrate studies were submitted to the Agency: two studies using the
waterflea Daphnia magna and one using crayfish, Procambarus simulan s (MRIDS 00059738, 00071123, and 00153772 respectively ).21 A Daphnia magna study using techni cal grade pendimethalin had an EC 50 of 280 ppb (C.I. 230

- 330) and is considered to be an acceptable study. The other Daphnia magna study used the formulation containing 45.6% active ingredient with the EC 50 = 5.1 ppm (5100 ppb) formulation. This study is considered to be acceptable for formulated study.

The crayfish study is categorized as supplemental due to the precipitate being observed in concentrations of 1.0 ppm and more; the dissolved O 2 concentration is less than 40% of saturation; and DMSO was u sed as a solvent which tends to increase mortalities rather than
decrease them. This EC 50 for this study is greater than 1.0 ppm (1000 ppb). Acute toxicity of pendimethalin technical to freshwater invertebrates is categorized as highly toxic and moderately toxic. Pendimethalin formulation is categorized as moderately toxic.

One chronic freshwater invertebrate study (MRID 00100504) was submit ted to the Agency. This study is a Daphnia magna life cycle study using a technical grade pendimethalin. The 21

- day NOAEC is 14.5 ppb (0.0145 ppm). The NOAEC is based on reduced production of Daphnia. LOAEC = 0.0172 ppm (17.2 ppb). Mortality was observ ed in the study with 100% mortality at the 2 highest dose levels of 35.8 and 74.2 ppb. No appreciable mortality observed at 3 lowest concentration levels of 4.3, 8.2, and 14.5 ppb. Reduction of productivity of 50% occurred at 22.1 and 17.5 ppb concentrat ion levels.

Estuarine/Marine Invertebrates

Two acute freshwater invertebrate studies are available for pendimethalin. An acceptable study with the eastern oyster ( Crassostrea virginica , MRID 00131772) used tech nical grade and formulated pendimethalin (AC 92, 533). The study reported a 48

- hour EC 50 value of 210 ppb (C.I. 160

- 340 ppb) for technical grade pendimethalin and a 48

- hour EC50 value of 450 ppb for
the formulation , indicating that pendimethalin is highly toxic to oysters.

In addition, an acceptable study tested the toxicity of technical grade pendimethalin and the formulation AC92, 533 to pink shrimp ( Penaeus duorarum , MRID 00131775)

. The study had a

96

- hour LC 50 value of 1.6 ppm (C.I. 1.2

- 2.2 ppm) for technical grade pendimethalin and a 96

- hour LC 50 value of 11 ppm (C.I. 8.9

- 16 ppm) for the formulated product. This study suggests that pendimethalin is moderately toxic to pink shrimp.

Chronic data on the toxicity of pendimethalin to estuarine/marine invertebrates are not available. This is identified as a data gap.

Benthic Invertebrates

A 28

- day spiked sediment study (MRID 47891601 ) for the non

- biting midge ( Chironomus riparius ) has been submitted and revie wed. Although the study is scientifical ly sound based on
methods described in the non

- guideline OECD Guideline 218 (“Sediment

- Water Chironomid Toxicity Test Using Spiked Sediment”), it is classified as ‘supplemental’ because NOAEC and LOAEC values were not established, and the highest test conc entration was well below the limit concentration of 1,000 mg a.i./kg sediment. Based on the results of the study, no treatment

related effects on mortality, emergence, or development rates were observed at the highest mean

measured treatment level in sedi ment of 203 mg a.i./kg dw. In addition, total organic carbon (TOC) was not reported in this study. Without information on TOC it is not possible to determine whether the lack of treatment related effects were due to a relative insensitivity to the

test substance or whether pendimethalin bound to the available organic carbon such that is was22 not bioavailable for the test organism. Concentrations of pendimethalin were measured in sediment, overlying water, and pore water at 0 and 28 days. In general, c oncentrations of pendimethalin remained largely associated with the sediment phase; the highest pendimethalin concentration in overlying water was measured at 80 μg a.i./L, and no quantifiable levels (<50 μg a.i./L) were detected in pore water. Given pend imethalin’s propensity to partition to sediment, the lack of sediment toxicity data for benthic invertebrates has been identified as a data gap and a source of uncertainty for estimation of risk to benthic organisms in previous ecological
risk assessments.

4.1.3 Plants

Tier II terrestrial plant toxicity testing was conducted with the TGAI, rather than the TEP as required by the non

- target plant protection data requirements specified in 40 CFR Part 158.
These data will be needed for ESA effects determination. Based on the available Tier II seedling emergence and vegetative vigor toxicity data for the TGAI, ryegrass and lettuce are the most sensitive monocot and dicot plants, respectively. However, ryegrass is the most sensitive in the vegetative vigor test as compared to the seedling emergence test, and lettuce shows similar sensitivity in both tests. It is important to note that all ten test species showed effects >25% in the seedling emergence test, whereas two of the ten test species (including radish and cucumber, both dicots) showed no effect in the vegetative vigor test at the highest treatment level of 4.0 lbs
a.i./A. This study did not test the maximum application rate for currently registered use s of pendimethalin. In addition, use of the TGAI data may underestimate toxicity to plants as the TEP may include adjuvants or surfactants that increase the toxicity of the parent compound. The
most sensitive EC 25 and NOAEC values for ryegrass and lettuce, based on the available TGAI data, are bolded in Tabl e 5 .3

.

Table 5 .3 . Summary of Tier II Terrestrial Plant Toxicity Data for Pendimethalin. Crop Species EC 25 (lbs a.i./A) NOAEC (lbs a.i./A) Most sensitive
parameter Seedling Emergence

Monocots Oat 1.0 0.25 Plant height Ryegrass 0.02 0.01 Dry weight

Corn 0.68 0.5 Plant height

Onion 0.08 0.06 Dry weight

Dicots Soybean 4.7 2.0 Dry weight

Lettuce 0.09 0.063 Dry weight

Radish 0.86 0.13 Plant height

Tomato 0.2 0.13 Dry weight

Cucumber 2.4 0.25 Plant height Cabbage 0.44 0.25 Plant height Vegetative Vigor

Monocots Oat 0.78 0.5 Dry weight Ryegrass 0.034 0.0008 Dry weight

Corn 2.8 2.0 Plant height

Onion 0.56 0.5 Plant height

Dicots Soybean 0.27 0.13 Dry weight

Lettuce 0.10 0.003 Dry weight

Radish > 4.0 4.0 NA

Tomato 0.5 0.13 Dry weight

Cucumber > 4.0 4.0 NA23 Cabbage 4.8 2.0 Dry weight

Aquatic plant toxicity data submitted to the Agency show a range of EC 50 values from 5.2 ppb to

> 174 ppb. The most sensitive species tested are the green algae and marine diatom and the least sensitive species is the cyanobacteria (blue

- green algae). With respect to aquatic vascular and

non

- vascular plants ( Table 5 .4 ) , duckweed ( Lemna gibba ) and the marine diatom ( S keletonema

costatum ) are most sensitive to pendimethalin with respective EC 50 values of 5.6 μg a.i./L and 0.7 μg a.i./L.

Table 5 .4 . Summary of Most Sensitive Aquatic Plant Toxicity Data for Pendimethalin

. Species Acute Toxicity

120

- hr
LC 50 (μg a.i./L) 14

- day EC 50 (μg a.i./L) NOAEC (μg a.i./L) Endpoints (MRID)

Duckweed Lemna gibba

-- 12.5 5.6 Reduced Frond Number ( 42137101 )

Marine diatom
Skeletonema costatum 5.2

-- 0.7 Growth Inhibition ( 42372205 )

ECOTOX

I n addition to submitted data, available open literature will be used to evaluate the potential
direct effects of pendimethalin to the terrestrial receptors identified in this section. This includes toxicity data on the technical grade active ingredient, a nd when available, formulated products.

At this time, a full and complete ECOTOX search has not been performed, but will be conducted prior to the final risk assessment. The open literature studies will be identified through EPA’s ECOTOX database ( http://cfpub.epa.gov/ecotox/ ), which employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of data can also provide insight into t he direct and indirect effects of pendimethalin on biotic communities from loss of species that are sensitive to the chemical and from changes in structure
and functional characteristics of the affected communities.

Open literature toxicity data for othe r ‘target’ insect species (not including bees, butterflies, beetles, and non

- insect invertebrates including soil arthropods and worms), which include efficacy studies, are not currently considered in deriving the most sensitive endpoint for
terrestrial ins ects. Efficacy studies do not typically provide endpoint values that are useful for risk assessment (such as NOAEC, EC 50 , etc.), but rather are intended to identify a dose that maximizes a particular effect (such as EC 100 ). Therefore, efficacy data and n on

- efficacy toxicological target insect data will not be included in the ECOTOX open literature search.

4.2 Incident Database Review

A review of the Ecological Incident Information System (EIIS, v. 2.1) and Aggregate Incident databases for ecological incid ents involving pendimethalin was completed on April 11, 2012

. This database consists of exposure incident reports submitted to the EPA from 1994 to present. A search for incidents involving pendi me thalin was also conducted in the American Bird Conservancy’s Avian Incident Monitoring System (AIMS).24 The reports are listed in order of certainty, from highly probable to unrelated. Incidents listed in EIIS are categorized by the likelihood that a particular pesticide is associated with that particular
incident. These classifications include highly probable, probable, possible, unlikely

, or unrelated. “Highly probable” incidents usually require carcass residues or clear circumstances regarding the exposure. “Probable” incidents include those where residue information was not available or circumstances were less clear than those for “highly probable”. “Possible” incidents occur when multiple chemicals may have been involved and the contribution of an indivi dual
chemical is not obvious. An “unlikely” incident classification is given when a given chemical is considered nontoxic to the type of organism involved or the chemical was analyzed and not detected in samples. The “unrelated” category is used for inci dents confirmed not to involve pesticides.

The number of reports listed in the EIIS database is believed to be only a small fraction of the total incidents involving organism mortality and damage caused by pesticides. Few resources are assigned to incid ent reporting. Reporting by states is only voluntary, and individuals discovering incidents may not be informed on the procedure of reporting these occurrences. Additionally, much of the database is generated from registrant

- submitted incident reports. I n addition, incident reports for non

- target organisms typically provide information only on mortality events and plant damage incidents. Except for phytotoxic effects in terrestrial plants, sublethal effects for organisms such as reduced growth or impaire d reproduction are rarely reported. Because of these logistical difficulties, EIIS is most likely a minimal representation of all pesticide

- related ecological incidents.

Registrants are legally required to provide detailed reports of only “major” ecologi cal incidents involving pesticides, while “minor” incidents are reported aggregately. Based on 40 CFR §159.184, an ecological incident is considered major and must be submitted to the Agency by the registrant if any of the following criteria are met:

Fish or wildlife: (A) Involves any incident caused by a pesticide currently in Formal Review 7 for ecological

concerns. (B) Fish: Affected 1,000 or more individuals of a schooling species or 50 or more
individuals of a non

- schooling species. (C) Birds: Affect ed 200 or more individuals of a flocking species, or 50 or more individuals of a songbird species, or 5 or more individuals of a predatory species. (D) Mammals, reptiles, amphibians: Affected 50 or more individuals of a relatively common or herding specie s or 5 or more individuals of a rare or solitary species. (E) Involves effects to, or illegal pesticide treatment (misuse) of a substantial tract of habitat (greater than or equal to 10 acres, terrestrial or aquatic).
Plants : (A) The effect is alleged t o have occurred on more than 45 percent of the acreage exposed to the pesticide.

The EIIS database contained 70 major incidents involving pendimethalin . The reports included 65 terrestrial plant incidents, 2 fish incidents, and 1 avian incidents. In respect to
the likelihood that pendimethalin caused the reported incidents, the certainty ranged from

7 Formal Review means Special Review, Rebuttable Presumption Against Registration (RPAR), FIFRA section 6(c) suspension proceeding, or FIFRA section 6(b) cancellation proceeding, whether completed or

not.25 unlikely to highly probable. The majority of reported incidents were identified as probable or highly probable. 27 of the incidents resulted from regi stered uses, 4 were misuses

, and the remaining use patterns are unknown. A summary of ecological incidents involving pendimethalin included in the EIIS database are listed in Appendix B

.

The AIMS database contains 2 avian incidents involving pendimethalin

, both of which are also captured in EIIS

.

All other incidents are classified as ‘minor’. All ecological incidents classified as ‘minor’ only need to be aggregately reported as quarterly counts of incidents by the registrant(s). Ecological incidents reported in aggregate reports include those categorized as ‘minor fish and wildlife’ (W

B), ‘minor plant’ (P

- B), and ‘other non

- target’ (ONT) incidents. ‘Other non

- target’ incidents include reports of adverse effects to insects and other terrest rial inverte brates. For pendimethalin, the registrants have reported 4 minor fish and wildlife incidents, 1,035 minor plant incidents, and 3 “other non

- target” incdents. Unless additional information on these aggregated incidents becomes available, they will be assumed to be representative of registered uses of pendimethalin in the risk assessment.

4.3 Ecosystems Potentially at Risk

Pendimethalin may be applied on a variety of food/feed crops, including (but not limited to), citrus, nut crops, pome fruits, stone fruits, flavoring and spice crops, fruiting vegetables, leafy and stem vegetables, root crop vegetables, seed and pod vegetables, forage grasses and legumes, grain crops, fruits trees, and soybeans . In addition, it may be used on numerous non

- food sites ( e.g. ornamentals, christmas tree plantations, and turf). Thus, the ecosystems at risk may be extensive in scope, and as a result it may not be possible to identify specific ecosystems during the development of a baseline risk assessment. In genera l terms, terrestrial ecosystems potentiall y at risk due to the use of pendimethalin could include the treated field and areas immediately adjacent to the treated field that may receive drift or runoff. Areas adjacent to the
treated field could include cul tivated fields, fencerows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats and other uncultivated areas. C urrent label directions for pendimethalin require vegetative buffer strips and impose limitations to reduce the pote ntial for spray drift to impact areas adjacent to the treated field. However, due to t he potential persistence of pendimethalin under certain circumstances, it is expected to drift and/ or runoff due to application to food crops and certain non

- crop sites , resulting in possible exposure to aquatic ecosystems. Aquatic ecosystems potentiall y at risk due to the use of pendimethalin include water bodies adjacent or downstream from the treated field and might include impounded bodies such as ponds, lakes and r eservoirs, or flowing waterways such as streams or
rivers. For uses in coastal areas, aquatic habitat also includes marine ecosystems, such as
estuaries.

5 Assessment Endpoints

Assessment endpoints are defined as “explicit expressions of the actual environmental value that is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the valued attributes of the environment that are considered to be at risk; and 2) operationall y defining the assessment endpoint in terms of an ecological entity ( i.e. , a community of fish and26 aquatic invertebrates) and its attributes ( i.e. , survival and reproduction). Therefore, selection of the assessment endpoints is based on valued entities ( i .e. , ecological receptors), the ecosystems potentially at risk, the migration pathways of pesticides, and the routes by which ecological receptors are exposed to pesticide

- related contamination. The selection of clearly defined assessment endpoints is imp ortant because they provide direction and boundaries in the risk assessment for addressing risk management issues of concern. Changes to assessment endpoints are typically estimated from the available toxicity studies, which are used as the measures of
ef

fects to characterize potential ecological risks associated with exposure to pesticides, such as pendimethalin

.

To estimate exposure concentrations, the ecological risk assessment considers applications at the maximum application rate to fields that have vulnerable soils. The most sensitive toxicity endpoints are used from surrogate test species to estimate treatment

- related direct effects on acute mortality and chronic reproductive, growth and survival assessment endpoints. Toxicity
tests are intended t o determine effects of pesticide exposure on birds, mammals, fish, terrestrial and aquatic invertebrates, and plants. These tests include short

- term acute, sub

- acute, and reproduction studies and are typically arranged in a hierarchical or tiered system t hat progresses from basic laboratory tests to applied field studies. The toxicity studies are used to evaluate the potential of a pesticide to cause adverse effects, to determine whether further testing is needed, and to determine the need for precautiona ry label statements to minimize the potential adverse
effects to non

- target animals and plants.

An open literature search will be conducted to determine any relevant endpoints. The search will focus on survival, growth and reproductive effects for aquati c and terrestrial effects of pendimethalin . More sensitive endpoints from acceptable open literature studies will be included in the ecological risk assessment.

6 Conceptual Model

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically significant concentrations. An exposure pathway is the means by which a pesticide moves in the environment from a source to an ecological receptor. For an ecological pathway to be complete,
it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure.

A conceptual model provides a written description and visual representation of the predicted
relationsh ips between pendimethalin , potential routes of exposure, and the predicted effects for the assessment endpoint. A conceptual model consists of two major components: risk hypothesis and a conceptual diagram (USEPA, 1998).

6.1 Risk Hypothesis

Risk hypotheses are specific assumptions about potential adverse effects ( i.e. , changes in assessment endpoints) and may be based on theory and logic, empirical data, mathematical models, or probability models (USEPA 1998). For this as sessment, the risk is stressor

- initiated,
where the stressor is the release of pendimethalin into the environment. The following risk hypotheses are presumed for this screening

- level assessment:27 Pendimethalin , when used outdoors in accordance with regist ered labels, may lead to off

site movement of the compound via agricultural and urban runoff, spray drift, and eroded soil leading to exposure of nontarget plants and animals

. Based on information on the environmental fate, mode of action, direct toxicity

, and potential indirect effects, EFED

assu mes that registered uses of pendimethalin have the potential to cause reduced survival, growth, and reproduction to non

- target terrestrial and/ or aquatic animals and plants.

The conceptual model is a generic gra phic depiction of the risk hypothesis. It includes the potential pesticide or stressor ( pendimethalin and possible metabolites, as well as synergists), the source of the pesticide and/or transport pathways, exposure media, exposure point, biological

recep tor types, and attribut able changes.

6.2 Conceptual Diagram

The conceptual model is a generic graphic depiction of the risk hypothesis. Based on an examination of the physicochemical properties of pendimethalin , the fate and disp osition in the environment, and mode of application, a conceptual model was developed that represents the possible relationships between the stressors, ecological receptors, and the assessment endpoints. Through a preliminary iterative process of examinin g available data, the conceptual model ( i.e

., the representation of the risk hypothesis) may be refined to reflect the likely exposure pathways and the organisms that are most relevant and applicable to this assessment ( Figures 7

- 1a and 7

- 1b ). They include the potential pesticide or stressor ( pendimethalin , but the presence of toxicologically important metabolites and/ or synergists cannot be ruled out), the sources and/ or transport pathways, exposure media and exposure points, biological receptor t ypes and attribute changes.

In order for a chemical to pose an ecological risk, it must reach ecological receptors in biologically significant concentrations. An exposure pathway is the means by which a pesticide
moves in the environment from a source to an ecological receptor. For an ecological exposure pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure. The
assessment of e cological exposure pathways, therefore, includes an examination of the source and potential migration pathways for constituents, and the determination of potential exposure

routes.

Under the possible uses of pendimethalin , the sources and mechanisms of re lease of the compounds are fro m ground or aerial spray . Note that this conceptual model considers agricultural applications as well as non

- agricultural applications. Surface runoff from the areas of application is assumed to depend on factors such as top ography, irrigation, and rainfall events. Direct deposition may result in contamination of food items that may be consumed by terrestrial organisms. Spray drift results in contaminated adjacent areas, including bodies of water. Leaching to groundwater i s not considered an important source because pendimethalin show s low mobility in a variety of soils. Pendi me thalin appear s to have the potential for volatilization, with a vapor pressure and vapor pressure of

~ 3 .0 E - 5 torr and Henry’s Law constant of

~ 8 .6 E - 7

atm/m 3

- mol. In addition, pendimethalin has been detected in air, rain and snow according to a compilation of studies by Majewski and Capel (1995).28 For aquatic receptors, the major point of exposure is through direct contact with the water column, sed iment, and pore water (gill/integument) contaminated with spray drift (from spray application) and/or runoff and flow ( e.g. , piped storm drains) from treated areas. Indirect effects to aquatic organisms (both fish and aquatic invertebrates) can also occur through impact to various food chains. The representative aquatic receptors are certain freshwater and estuarine/ marine fish, invertebrates, and, in certain cases, aquatic plants. The major point of exposure for terrestrial animals is consumption of fo od contaminated with residues such as grass, foliage, and small insects. For plants, the point of exposure is direct contact or root uptake. The representative terrestrial receptors are mammals, birds and terrestrial plants. The attribute changes used t o assess risk to terrestrial receptors depend on the type of test ( e.g. , reduced survival, growth, or reproduction for animals and seedling emergence and vegetative vigor for plants). It should be noted, that these species do not cover all the possible sp ecies in the animal and plant kingdoms; certain taxa are considered as surrogates for other taxa. For example, fish are considered surrogates for aquatic phase amphibians.

This conceptual model also shows information about the potenti al for biomagnificat ion for pendimethalin (see piscivorous birds and mammals in Fig. 7

- 1b ). The reported value of log octanol/ water partition coefficient of 5.18 suggests that pendimethalin has the potential to bioaccumulate in aquatic organisms assuming that chemical metab olism is negligible. Maximum
BCFs for pendimethalin are 5100 x for bluegill sunfish, 100x for catfish and negligible for the

guppy. Depuration appeared to be moderately slow, with ~10

- 15% of the initial residues remaining after 14 days. Thus, it appears that there is potential for bioaccumulation/ bioconcentration in aquatic organisms and biomagnification in terrestrial organisms.

Pendimethalin has a solubility of 0. 275 mg/L and a high log K OW of 5.2 . These prope rties suggest that the chemical could partition with the sediments and particulate suspended in bodies
of water. Pendimethalin has the potential to accumulate in the sediments, especially after repeated exposures (applications), where it could persist. Such sediments could serve as

re positories of the chemical for extended periods of time and could potentially be toxic to sediment dwelling organisms, affecting the food chain. These issues will also be assessed in the
risk assessment for pendimethalin

.29 Figure 7

- 1a. Aquatic conceptual model depicting stressors, exposure pathways, and potential effects to aquatic organisms from the use of pendimathalin on agricultural and

non
- agricultural sites

1 Includes flow across vegetation and vegetated drainage systems ( e.g. , swales) and flow across impervious surfaces and through impervious (piped) storm drains.

2 Immobilization is considered equivalent to mortality in toxicity tests for aquatic invertebrates.

Dotted lines indicate exposure pathways that have a low li kelihood of contributing to ecological
risk.30 Figure 7

- 1b. Terrestrial conceptual model depicting stressors, exposure pathways, and potential effects to terrestrial organisms from the use of pendimethalin on agricultural and

non
- agricultural sites

Dotted lines indicate exposure pathways that have a low likelihood of contributing to ecological
risk.

1 Includes flow across vegetation and vegetated drainage systems ( e.g. , swales) and flow across impervious surfaces and through impervious (piped) stor m drains.

7 Analysis Plan

In order to address the risk hypothesis, the potential for adverse effects on the environment is estimated. Usage, environmental fate and transport , and ecological effects of pendimethalin ar e characterized and integrated to assess the risks. This is accomplished using a risk quotient (ratio of exposure concentration to effects concentration) approach. Although risk is often defined as the likelihood and magnitude of adverse ecological effec ts, the risk quotient

- based approach does not provide a quantitative estimate of likelihood and/ or magnitude of an adverse effect.31 However, as outlined in the Overview Document (USEPA 2004), the likelihood of effects to individual organisms from particul ar uses of a chemical is estimated using the probit dose

response slope and either the level of concern (discussed below) or the actual calculated risk quotient value.

This analysis plan will be revisited and may be revised depending on the data availab le in the open literature and the information submitted by the public or the registrant in response to the opening of the Registration Review docket.

7.1 Stressors of Concern

The focus of this assessment is on the parent material, pendimethalin . However, the Agency will review open literature to identify degradate(s) of potential toxicological concern ( e.g. 3,5

- d initrobenzyl alcohol metabolite, 2,4

- d initrobenzyl alcohol metabolite ).

Toxicity data fo r environmental mixtures of pendimethalin w ith other pesticides (those mixtures occurring in the environment following application), if available, may be presented as part of the ecologic al risk assessment. Pendimethalin may be applied in tank mixtures with other products approved for use on regis tered crops. It is expec ted that the toxic effect of pendimethalin , in combination with other pesticides used in the environment, is likely to be a function of many factors including, but not necessarily limited to (1) the exposed species, (2) the co

- form ulants in
th e mixture, (3) the ratio of pendimethalin and co

- formulants concentrations, (4) differences in the pattern and duration of exposure among formulants, and (5) the differential effects of other physical/ chemical characteristics of the receiving waters ( e.g. organic matter present in sediment and suspended water). A discussion of implications of the available pesticide mixture effects data on the confidence of risk assessment conclusions will be addressed in the risk description of
the final ecol ogical assessment.

7.2 Measures of Exposure

In order to estimate risks of pendime th alin exposures in aquatic and terrestrial environments, all exposure modeling and resulting risk conclusions will be made based on maximum application
rates for the current us e patterns. Available monitoring data will also be considered when describing potential environmental exposure to non

- target organisms.

Measures of exposure are based on aquatic and terrestrial models that predict estimated
envi ronmental concentrations o f pendimethalin using maximum labeled application rates and methods, as well as any mitigation measures specifically indicated on the label.

Additional information on the terrestrial exposure models and screening tools employed in EPA ecological risk assessments for pesticides can be found at http://www.epa.gov/oppefed1/models/terres trial/

.

More information on aquatic pesticide exposure models can be found at http://www.epa.gov/oppefed1/models/water/index.htm

.32 Dietary exposure to terrestrial organisms

Measures of expo sure for terrestrial mammals, birds, reptiles and amphibians similarly incorporate maximum proposed use rates but rely less on fate properties. Terrestrial exposures
are estimated usi ng a number of methods. For pendimethalin , acute and chronic terrestrial exposure estimates are derived directly from empirically determined observations of pesticide residues on various terrestrial food items. The Kenaga nomogram, as modified by Fletcher et al

, (Kenaga and Hoerger, 1972; Fletcher et al , 1994) is used to rela te pesticide application rates to residues on terrestrial food items. The surface residue concentration (ppm) is estimated by multiplying the application rate (pounds active ingredient per acre) by a value specific to each food item. For numerous applicat ions for a given use, the exposure model incorporates a first

order decay rate dependent on the foliar dissipation half

- life of the chemical. In the absence of foliar dissipation data, a default foliar dissipation half

- life of 35 days is used.

Inhalation, drinking water and dermal exposure

Two screening tools were utilized to assess th e potential for exposure of pendimethalin to terrestrial organisms via inhalation and drinking water exposure. The S creening T ool for

I nhalation R isk (STIR v.1.0, November 1 9, 2010) was used to calculate an upper bound estimate of exposure using vapor press ure and molecular weight of pendimethalin for vapor phase exposure, as well as the maximum application rate and method of application for spray drift. STIR incorporates re sults from several toxicity studies including acute oral and inhalation rat toxicity (oral LD 50 = 1050 mg/kg

- bw and LC 50 > 320 mg/L, respectively) as well as the most sensitive acute oral avian toxicity endpoint ( mallard duck , LD 50 = 1421 mg ai/kg bw). Bas ed on the results of the STIR model, inhalation exposure alone was determined not to be a potential pathway of concern for avian and mammalian species on an acute basis.

Inhalation exposure via spray drift and vapor

- ph ase of pendimethalin alone does not appear to be of concern. The analysis of the inhalation route in STIR does not consider that aggregation with other exposure pathways such as dietary, dermal, or drinking water may contribute to a total exposure that has a potential for effects to non

- ta rget animals. However, the Agency does consider the relative importance of other routes of exposure in situations where data indicate that pesticide exposures through other routes may be potentially significant contributors to wildlife risk (US EPA, 2004)

.

The S creening I mbibition P rogram (SIP v.1.0, Released June 15, 2010) was used to calculate an upper bound estimate of exposure using pendimethalin solubility ( 0.3 mg/L), the most sensitive acute and chronic avian oral toxicity endpoint ( mallard duck , LD 50 = 1421 mg ai/kg bw and
NOEL = 141 mg/kg

- diet , respetively ) and the most sensitive acute and chronic mammalian toxicity endpoints ( oral LD 50 = 1050 mg/kg

- bw and NOAEL = 500 mg/kg

- bw, respectively). Drinking water exposure alone was determined not to be a potential pathway of concern for avian and mammalian species on an acute or chronic basis.

Although drinking water exposure alone does not appear to be of concern, this does not take into account that when aggregated with other exposure pathways (dieta ry food sources, dermal, inhalation) drinking water may contribute to a total exposure that has a potential for effects on

non

- target animals and should be explored further. Because there is a high degree of
conservatism in the SIP 1.0 exposure estimate, there is limited expectation that use scenarios not triggering a SIP 1.0 concern would contribute significantly to aggregate risks from water plus33 diet when a refined water exposure model is incorporated in the actual quantitative risk

assessment.

Althou gh not available at this time, the Agency is actively pursuing modeling techniques to account for dermal exposure via direct application of spray and by incidental contact with contaminated vegetation, soil and water.

Exposure to terrestrial plants

TerrP lant is used by EFED as a Tier 1 model for screening level assessments of pesticides. The purpose of TerrPlant is to provide screening level estimates of exposure to terrestrial plants from single pesticide applications. The model does not consider exposu res to plants from multiple pesticide applications. TerrPlant derives pesticide EECs in runoff and in drift. RQs are developed for non

- listed and listed species of monocots and dicots inhabiting dry and semi

aquatic areas which are adjacent to treatment s ites. Once suitable terrestrial plant data are submitted to the Agency, this model will be used to determine the potential risks to terrestrial plan ts following applications of pendimethalin

.

Aquatic exposure modeling

The models used to predict aquatic EECs are the Pesticide Root Zone Model coupled with the Exposure Analysis Model System (PRZM/EXAMS). PRZM (v.3.12.2, May 2005) and EXAMS (v.2.98.4.6, April 2005) are simulation models coupled with the input shell PE5.pl (August, 2007) to generate daily ex posu res and 1

- in

- 10 year EECs of pendimethalin , that may occur from spray drift and runoff to surface water bodies adjacent to application sites. PRZM simulates pesticide application, movement and transformation on an agricultural field and the resultant pesticide loadings to a receiving water body via runoff, erosion and spray drift. The EXAMS model simulates the fate of the pesticide and resulting concentrations in the water body. The standard scenario used for ecological pesticide assessments assumes application to a 10

- hectare agricultural field that drains into an adjacent 1

- hectare water body that is 2 meters deep (20,000 cubic meters volume) with no outlet. PRZM/ EXAMS is used to estimate screening

- level

expos ure of aquatic organisms to pendimeth alin and/ or its transformation products, should they be of concern. The measure of exposure for aquatic species is the 1

- in

- 10 year return peak or rolling mean concentration. The 1

- in

- 10 year peak is used for estimating acute exposures of
direct effects to aquatic organisms. The 1

- in

- 10

- year 60

- day mean is used for assessing chronic exposure to fish and aquatic

- phase amphibians. The 1

- in

- 10

- year 21

- day mean is used for assessing aquatic invertebrate chronic exposure.

At the present time, EFED considers the use of the impervious scenario (a PRZM modeling scenario) as the most suitable available modeling approach for simulating runoff from impervious surfaces such as roads, sidewalks, patios and parking lots. The PRZM impervious scenario may be used in th e Tier 2 coupled aquatic models PRZM/EXAMS along with the residential or other suitable scenario such as rights

- of

- way (ROW) to obtain EECs. The conceptual model for the residential scenario integrates simultaneous modeling of the individual
use scenario with an impervious scenario. This approach assumes that no watershed is completely covered by either the 1⁄4 acre lot (the basis for the residential scenario) or undeveloped land (the basis for the ROW scenario) for residential and ROW use patterns;
therefo re, differential amounts of runoff will occur within the watershed. The impervious scenario was developed to represent the paved areas within a watershed not including roads,34 parking lots, sidewalks, and buildings outside the 1⁄4 acre lot (the 1⁄4 acre lot sc enario accounts for impervious surfaces such as buildings within the represented area). By modeling a separate scenario for impervious surfaces, it is also possible to estimate that amount of exposure that could occur when the pesticide is oversprayed ont o this surface. Using two scenarios in tandem requires post

- processing of the modeled output in order to derive a weighted EEC that represents the contribution of both the pervious ( i.e. , residential and ROW scenarios) and the impervious
surfaces.

In general, incorporation of impervious surfaces into the exposure assessment results in increasing runoff volume in the watershed, which tends to reduce overall pesticide exposure. For the purposes of risk assessment alternate assumptions for percent imperv ious surfaces, percentage of use site treated, and percentage of overspray may be considered in order to characterize the assumptions of the ecological risk assessment in the context of the individual exposure assessment and risk conclusions. For example, previously tested assumptions used in the endangered species assessments may be considered for characterization ( i.e. , 10% and 30% impervious surfaces, 10% lot treated, and 0%, 1% and 10% overspray) unless other relevant values can be determined ( i.e. , mo deling may be completed for the impervious surface with 0%, 1% and 10% overspray to provide lower and upper bound values). The results of these alternate modeling exercises may be discussed in the assessment.

Gi ven the aquatic toxicity of pendimethalin a nd its likelihood to occur in sediment, the Agency will also consider the potential exposures resulting from benthic/ sediment concentrations. Pore water concentrations are commonly used to predict toxicity of non

- ionic substances in sediments
and charact erize exposure to organisms that spend time in or near sediments (Di Toro et al. 1991; US EPA 2002). PRZM/ EXAMS estimates 1

- in

- 10

- year peak and 21

- day mean EECs for
pore water.

Since pendimethalin has uses on rice, the screening

- level Tier 1 Rice Model v.1.0 will be utilized to obtain estimated exposure concentrations (EECs) related to that use. The Tier I Rice Model v1.0 relies on an equilibrium partitioning concept to provide conservative estimates of environmental concentrations resulting from applic ation of pesticides to rice paddies. When a pesticide is applied to a rice paddy, the model assumes that it will instantaneously partition between a water phase and a sediment phase. Among the assumptions of this model, the degradation of the pesticide a nd the mass transfer from the aqueous phase to the sediment are not considered. Also, volatilization and other dissipation processes are not considered. If LOCs are exceeded using the Tier 1 rice model, estimates may be made using a provisional model,

Pes ticides in Flooded Applications Model (PFAM), to better characterize the risk.

Extent of Exposure

Two spray drift models, AgDisp and AgDRIFT, are used to assess exposures of aquatic and terrestrial organisms to pendimethalin deposited in terrestrial and aquatic habitats by spray drift. AgDrift (version 2.01; dated 5/24/2001) is the model most commonly used to simulate spray drift into terrestrial and aquatic environments. A g D isp (version 8.13; dated 12/14/2004 ) (Teske
and C urbishley, 2003) is u sed when a parameter needs to be modeled that is not available in AgDrift . Spray drift analysis will be an important part of the analysis in defining the potential area of effects for endangered species.

Bioaccumulation35 The potentia l for bioaccumulation for the chemical is assessed using the KABAM model, as well the results from bioconcentration in fish studies ( e.g., the bioconcentration factors). This model is parameterized using relevant reviewed registrant

- submitted environmenta l fate and transport
data.

As indicated in Table 3.1 and its associated text in Section 3

, pendimethalin has the potential to bioconcentrate in aquatic organisms and there is also some potential to biomagnify in terrestrial organisms. The poten tial for b ioaccumulation of pendimethalin will also be examined in the risk

assessment. Because pendimethalin has a fairly high log K OW ( 5.18 ) and the chemical may be persistent in water (aqueous photolysis half

- life of 42 days) and sediments (>10 days for aquatic metabolism), there could be a potential for bioaccumulation. The maximum bioconcentration
factor is 5100 x for whole fish and the depu ration rate is fairly slow (MRIDs 00156726 and
00158235 ).

B ioaccumulation will be assessed using the results fr om bioaccumulation in fish studies, as well as the KABAM model (K OW (based) Aquatic BioAccumulation Model, version 1.0, 2009), adjusting for biotransformation rates. KABAM is used to estimate potential bioaccumulation of hydrophobic organic pesticides in freshwater aquatic ecosystems and risks to mammals and birds consuming aquatic organisms which have bioaccumulated these pesticides. Monitoring data and biotransformation rates in terrestrial species will also be evaluated, to assess the potential for
bio accumulation in terrestrial food webs.

7.3 Measures of Effect

Ecological effects data are used as measures of direct and indirect effects to biological receptors. Data are typically obtained from registrant

- submitted studies or from literature studies identi fied by ECOTOX. The ECOTOX database provides more ecological effects data in an attempt to bridge existing data gaps. ECOTOX is a source for locating single chemical toxicity data and potential chemical mixture toxicity data for aquatic life, terrestrial plants, and wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research and Development, and the National Health and Environmental Effects Research Laboratory's Mid

- Continent Ecology Division.

The acute measures of effect used for an imals in this assessment are the LD 50 , LC 50 and EC 50

. LD stands for "Lethal Dose", and LD 50 is the amount of a material, given all at once, that is estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration”
and LC 50 i s the concentration of a chemical that is estimated to kill 50% of the test organisms.
EC stands for “Effective Concentration” and the EC 50 is the concentration of a chemical that is estimated to produce a specific effect in 50% of the test organisms. En dpoints for chronic measures of exposure for listed and non

- listed animals are the NOAEL/NOAEC and NOEC.
NOAEL stands for “No Observed

- Adverse

- Effect

- Level” and refers to the highest tested dose of a substance that has been reported to have no harmful (ad verse) effects on test organisms. The NOAEC ( i.e. , “No

- Observed

- Adverse

- Effect

- Concentration”) is the highest test concentration at which none of the observed effects were statistically different from the control. For non

- listed plants, only acute exposur es are assessed ( i.e. , EC 25 for terrestrial plants and EC 50 for aquatic plants); for listed plants either the NOAEC or EC 05 is used.36 At the time of the risk assessment, updated information on the potential effects of pentimethalin

on non

- target animals wi ll also collected from the Ecological Incident Information System (EIIS), Aggregrate Incident Reports and the Avian Monitoring Information System (AIMS).

Where available, sub

- lethal effects observed in both registrant

- submitted and open literature
studi es will be evaluated qualitatively. Such effects may include behavioral changes ( e.g. , lethargy and changes in coloration). Quantitative assessments of risks, though, are limited to those endpoints that can be directly linked to the Agency’s assessment e ndpoints of impaired survival, growth and reproduction.

The assessment of risk for direct effects to non

- target organisms makes the assumption that the toxicity of pendimethalin to birds is similar to that of pendimethalin’s toxicity to terrestrial

- phase amphibians and reptiles. The same assumption is made for fish and aquatic

- phase amphibians.

7.4 Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effects to determine the potential ecological risk from the use of pesticides and the likelihood of direct and indirect
effects to non

- target organisms in aquatic and terrestrial habitats. The exposure and toxicity effects data are integrated in order to evaluate the risks of adverse ecological effects on non

target species. For the assessment of risks, the risk quotient (RQ) method is used to compare exposure and measured toxicity values . EECs are divided by acute and chronic toxicity values. The resulting RQs are then compared to the Agency’s Levels of Concern (LOCs) (USEPA 2004). These criteria will be used to indicate when pendiemthalin uses, as directed on the label, have the poten tial to cause adverse direct or indirect effects to non

- target organisms. In addition, incident data from the EIIS will be considered as part of the risk characterization.

7.5 Deterministic and Probabilistic Assessment Methods

The quantitative assessment of risk will primarily depend on the deterministic point

- estimate based approach described in the risk assessment. An effort may also be made to further qualitatively describe risk using probabilistic tools that the Agency has developed. These tools
have be en reviewed by FIFRA Scientific Advisory Panels ( http://www.epa.gov/scipoly/sap/index.htm ) and have been deemed as appropriate means of refining assessments where deterministic approaches have identified risks.

7.6 Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to Federally

- listed threatened and/or endangered (listed) species from registered uses of pendimethalin . This assessment will be conducted i n accordance with the Overview Document (USEPA 2004), provisions of the ESA, and the Services’ Endangered Species Consultation Handbook (USFWS/NMFS, 1998).

The assessment of effects associated with the re gistration of pendimethalin is based on an action area. The action area is considered to be the area directly or indirectly affected by the federal action, as indicated by the exceedance of Agency LOCs used to evaluate direct or indirect37 effects. The Age ncy’s approach to defining the action area under the provisions of the Overview Document (USEPA 2004) considers the results of the risk assessment process to establish boundaries for that action area with the understanding that exposures below the Agency’s
defined LOCs constitute a no

- effect threshold. For the purposes of this assessment, attention will be focused on the footprint of the action ( i.e. , the area where pendimethalin application occurs), plus all areas where offsite transport may result in po tential exposure that exceeds the Agency’s LOCs. Specific measure s of ecological effect that define the action area for listed species include any direct and indirect effects and/ or potential modification of its critical habitat, including reduction in s urvival, growth, and reproduction as well as the full suite of sub

- lethal effects available in the effects literature. Therefore, the action area extends to a point where environmental exposures are below any measured lethal or sub

- lethal effect threshold for any biological entity at the whole organism, organ, tissue, and/ or cellular level of organization. In situations where it is not possible to determine the threshold for an observed effect, the action area is not spatially limited and is assumed to b e the entire United States.

7.7 Drinking Water Assessment

Drinking water assessments have been conducted to support human health risk assessments of pendimethalin , based on all the available environmental fate information. Any further drinking

water assessm ents will incorporate model estimates of pendimethalin in surface and ground waters. Concentrations in surface waters will be estimated using FQPA Index Reservoir Screening Tool (FIRST, v.1.1.1, 12/18/07) (or subsequently using PRZM/ EXAMS, with the
Index Reservoir if refinements are required). Ground water estimates of concentrations will be obtained using the Screening Concentration In GR O und Water (SCI

- GROW) model (v.2.3, July 2003) or PRZM

- GW ( in development)

. Further drinking water assessments will also include a summary of available surface and ground water monitoring data.

7.8 Endocrine Disruptor Screening Program

As required by FIFRA and the Federal Food, Drug, and Cosmetic Act (FFDCA), EPA reviews numerous studies to assess potential adverse outc omes from exposure to chemicals. Collectively, these studies include acute, subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include endp oints which may be susceptible to endocrine influence, including effects on endocrine target organ histopathology, organ weights, estrous cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecologi cal hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental and reproductive effects in different taxonomic groups. As part of its reregistration decision

, EPA reviewed these data and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), pendimethalin is subject to the endocrine screening part of the Endoc rine Disruptor Screening Program (EDSP).

EPA has developed the EDSP to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurrin g estrogen, or other such endocrine effects as the Administrator may designate.” The EDSP employs a two

- tiered approach to making the statutorily required
determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a38 chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stag e of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endocrine

- related effects caused by the substance, and
establish a dose

- response relatio nship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Accordingly, as part of registration review, EPA will issue future EDSP orders/data call

- ins, requiring the
submission of EDSP screening assays for pendimethalin

. For further information on the status of the EDSP, the policies and procedures, the current and future chemical lists, the test guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/

.

7.9 Preliminary Identification of Data Gaps

7.9.1 Environmental Fate Data Gaps

Currently the Agency has received one supplemental study on one soil type (MRID 40185104).
Aerobic soil metabolism studies facilitate an un derstanding of a compound’s degradation in soil resulting from pesticide interaction with soil microorganisms in aerobic (oxygen

- rich) conditions in the laboratory. The fate of pendimethalin formed in or deposited on soil cannot be
characterized without t he requested data. The Agency is asking for a minimum environmental fate data set for the pendimethalin in order to estimate aquatic and terrestrial exposure. Without these data, exposure estimates will be based on conservative assumptions.

In addition, i ndependently validated analytical methods for residues in water, sediment, and soil (environmental chemistry methods) submitted by the registrant are used to evaluate analyses described in submitted environmental fate and ecological effects stud ies. Submitted analytical methods are also used by various Federal, State, Tribal, and local agencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent la boratory validations for submitted analytical methods are necessary to confirm that the methods are functional and to confirm the levels of detection and quantitation reported in registrant

- prepared validations.

Table 8 .1 lists the status of the environme ntal fate data requirements for pendimethalin

.

Guideline Study Title MRID /
ACC No. Classification Data Gap?

835.2120 Hydrolysis 00106777 acceptable No

835.2240 Direct Aqueous Photolysis 00153763
43808201 acceptable No

835.2410 Soil Photolysis 00153764 acceptable No

835.4100 Aerobic Soil
Metabolism 40185104 Supplemental Yes39 7.9.2 Effects

For registration review, the following studies are requested to resolve uncertanties in the risk

assessment:

Guideline Number: 850.2100 Study Title: Avian acute oral toxicity test (passerine species) with TGAI Acute avian oral toxicity data are needed for either one waterfowl or one upland game species and one passerine species under the Part 158 data requirements (CFR 40 2008) for conventional pesticides. Based on previous risk as sessments agricultural use patterns of pendimethalin result
in acute LOC exceedances for listed and non

- listed birds. Because passerine species have higher 835.4200 Anaerobic Soil
Metabolism 40185105 acceptable No

835.4300 Anaerobic Aquatic
Metabolism 40813501
43154702 acceptable No

835.4400 Aerobic Aquatic
Metabolism 47385201 acceptable No

835.1240,
835.1230 Mobility

– Adsorption / Desorption ) 00153765
43041901 acceptable No

835.1410 Laboratory Volatility 00153766 acceptable No

835.6100 Terrestrial Field Dissipation 45364705, 45364706, 45 163802,
45136801 acceptable No

850.1730 Fish
Bioaccumulation 00156726
00158235 acceptable No

850.6100 Environmental Chemistry
Methods
and Associated Independent Laboratory
Validation (soil and water):
For the MRID# 45364705, 45364706, 45 163802,
45136801 No Data
Submitted N/A Yes40 metabolic rates due to their smaller sizes than either waterfowl or upland game bird species, and
b ecause they may utilize different metabolic pathways, they may be more or less sensitive to pendimethalin

. An additional line of evide nce from the reported bird incident (I00 7495

- 001

, Appendix B ), shows that the birds affected were passerines (although th e causes were uncertain). In order to properly characterize risk to passerines, an avian oral toxicity test is requested. A passerine study protocol should be submitted for review by the Agency prior to initiation of the study.

Guideline Number: OCSPP 850.1760 (in prep), OCSPP 850.1770 (in prep.) and OCSPP 850.1780 (in prep.) with TGAI Study Title: Whole sediment: acute invertebrates freshwater and marine

One chronic sediment toxicity test for a freshwater invertebrate has been submitted for pendimetha lin; however, this is not sufficient to satisfy the Agency’s updated data requirements for outdoor uses in 40 CFR Part 158 (October 26, 2007). For pendimethalin , available
information indicates that b enthic organisms may be exposed to pendimethalin which may be transported into aquatic environments via spray drift or runoff . Based on calculations in the most recent EFED assessment, the 21

- day sediment porewater EECs predicted for pendi methalin ranged from 0.4 to 8.00 μg a.i./L ( DP Barcodes 39116 and 39446 7). The upper end of this range
exceeds 0.1 of the most sensitive acute LC/EC 50 ( 210 μg a.i./L for eastern oyster ), which satisfies one of the criteria for requiring chronic whole sediment toxicity testing under 40 CFR Part 158. Furthermore, chronic repr oductive effects were seen in water column studies with aquatic invertebrates ( daphnid ), with a NOAEC = 14.5 μg a.i./L and LOAEC = 17.2 μg a.i./L.

Pendimethalin is expected to persist in sediments, based on half

- lives in submitted soil metabolism and aqua tic metabolism studies (aerobic soil, 172 days; aerobic aquatic metabolism,

27 days) (MRIDs 4018501 and 47385201 ). These half

- life values exceed the 40 CFR Part 158 criterion of 10 days.

The third set of trigger criteria for needing chronic testing (K d > 50 or log K OW >3 or K OC > 1000) is also met for pendimethalin (log K OW is 5.18 , and the mean K OC value is ~ 17,000)

. The physicochemical property triggers (K d , K OW and K OC ) reflect the propensity of the chemical to partition onto the particulate or organ ic matter phases of sediments. Exceeding any one of the physicochemical property triggers listed above is sufficient for indicating the pesticide has reasonable potential for partitioning to the sediment compartment.

Although a registrant submitted stud y is available for a chronic whole sediment test on
Chironomus riparius

, significant uncertainties associated with the study design ( e.g., total organic carbon was not measured) make the results unsuitable for use in risk assessment.

T herefore, c hronic who le sediment tests on Hyalella azteca , Chironomus riparius and Leptocheirus plumulosus are requested. Although both are freshwater species, Hyalella and
Chironomus differ subs tantially in their morphology ( crustacean vs. insect), ecological niche (epibenthic v. infaunal species), and physiology. Evidence also suggests that Hyalella is among the more sensitive invertebrates based on water column tests (Maund et al., 2002; Weston and Jackson, 2009). Pendimet halin has the potential to enter estuarine/marine water bodies based on current usage patterns that include coastal areas. Therefore, testing is also needed for an
estuarine/marine sediment

- dwelling invertebrate species ( e.g ., Leptocheirus plumulosus )

.41 Until the final OCSPP guidelines for chronic sediment toxicity tests are published, the registrant should submit a protocol to EFED for approval prior to test initiation, considering the following
methods:

• Test Method 100.4: Hyalella azteca 42

- d Test for Measuring the Effects of Sediment Associated Contaminants on Survival, Growth, and Reproduction in USEPA 2000 Methods for Measuring the Toxicity and Bioaccumulation of Sediment

- associated
Contaminants with Freshwater Invertebrates EPA 600/R

- 99/064 ( OCSPP 8 50.1770, in

prep. );

• Test Method 100.5: Life

- cycle Test for Measuring the Effects of Sediment

- associated
Contaminants on Chironomus dilutus (formerly known as C. tentans ) in USEPA 2000 Methods for Measuring the Toxicity and Bioaccumulation of Sediment

- asso ciated
Contaminants with Freshwater Invertebrates EPA 600/R

- 99/064 ( OCSPP 850.1760, in

prep. ); and

• Leptocheirus plumulosus in USEPA 2001 Method for Assessing the Chronic Toxicity of
Marine and Estuarine Sediment

- associated Contaminants with the Amphipod Leptocheirus plumulosus EPA 600/R

- 01/020 ( OCSPP 850.1780, in prep. ).

As an alternative to recommending the conduct of 2 chronic (life cycle) sediment toxicity tests, EFED would also consider a tiered testing approach for sediment toxicity testing. In this approach, sediment toxicity testing would first be conducted with the aforementioned species using the 10

- d (subchroni c) sediment toxicity test guidelines (OSCPP 850.1735 and 850.1740). Then, pending a comparison of estimated environmental concentrations (EEC) in sediment and porewater with toxicity results from the 10

- d sediment toxicity studies, the need for one or mor e chronic sediment toxicity studies would be determined. This tiered testing approach has the potential advantage of reducing the number of chronic (life cycle) studies that would be needed
when results of the 10

- d (subchronic) tests in conjunction with s ediment EECs indicate chronic testing is not likely to alter risk assessment conclusions. In some cases, however, this tiered testing approach may result in the conduct of both a 10

- d (subchronic) and a chronic (life cycle) study.

Guideline Number: 850.1 350 Study Title: Saltwater Aquatic Invertebrate Life Cycle Previously submitted studies indicate that estuarine/marine in vertebrates are among the most
sensitive taxa to pendimethalin on an acute basis, with effects expected below 210 μg a.i./L.

T he ne ed for a life cycle chronic toxicity of pendimethalin to estuarine/marine invertebrates is
indicated based on its aquatic toxicity and environmental fate properties according to 40 CFR Part 158 data requirements (October 26, 2007). Specifically:
1. Pendimeth alin is intended for use such that its presence in estuarine/marine environment in significant concentrations is expected;
2. The acute LC/EC 50 for pendimethalin is substantially lower than the 40 Part 158 trigger value of 1 mg/L ( 210 μg a.i./L for pendimethalin; Crassostrea virginica );
and
3. P revious risk assessments have indicated that the aquatic EECs are > 0.01 of the
acute LC/EC 50 values for the higher use patterns of pendimethalin , which is another condition for triggering an estuarine/marine invertebrate life cycle study.42 In the most recent assessment for pyrethrins, t he 21

- day aquatic estimated exposure concentrations modeled for all 8 scenarios modeled crop scenarios range
from 0. 51

– 14.3 μg/L ( DP barcodes 391166 and 391167 ).

An acute

- to

- chronic ratio is not appropriate because the freshwater acute and chronic data are based on the daphnid, which does not have a similar life history to the eastern oyster, the most
senstitive salt water invertebrate spe cies studied in the acute test . In ad dition, pendimethalin is very highly toxic to saltwater invertebrates on an acute basis. Therefore this study is necessary to reduce the uncertainty. Without this data chronic risk to saltwater species will be presumed.

Guideline Number: 850.1400 Study T itle: Saltwater Fish Early

- Life Cycle Previously submitted studies indicate that estuarine/marine fish are among the most sensitive

taxa to pendimethalin on an acute basis, with effects expected below 710 μg a.i./L.

T he need for a life cycle chronic toxicity study of pendimethalin to estuarine/marine fish is
indicated based on its aquatic toxicity and environmental fate properties according to 40 CFR Part 158 data requirements (October 26, 2007). Specifically:
1. Pendime thalin is intended for use such that its presence in estuarine/marine environment in significant concentrations is expected;
2. The acute LC/EC 50 for pendimethalin is substantially lower than the 40 Part 158 trigger value of 1 mg/L ( 710 μg a.i./L for pendime thalin; Crassostrea virginica );
and
3. P revious risk assessments have indicated that the aquatic EECs are > 0.01 of the
acute LC/EC 50 values for the highest use patterns of pendimethalin , which is another condition for triggering an estuarine/marine invertebrate life cycle study.
In the most recent assessment for pyrethrins, t he 21

- day aquatic estimated exposure concentrations modeled for all 8 scenarios modeled crop scenarios range
from 0. 51

– 14.3 μg/L ( DP barcodes 391166 and 391167 ).

An acute

- to

- chronic ration from the freshwater species is not appropriate because the acute and chronic studies used different freshwater species. In addition, pendimethalin is very highly toxic
to saltwa ter fish on an acute basis. Therefore this study is necessary to reduce the uncertainty. Without this data chronic risk to saltwater species will be presumed.

Guideline Numbers: 850.4150 and 850.4250 Study Title: Vegetative vigor and Seedling emergence, TierII 8 with TEP Terrestrial plant testing was conducted with TGAI and did not include solvent controls. The use
of TEP instead of TGAI is recommended for all terrestrial non

- plant target studies. Testing with only the TGAI may underestimate toxicity to plants because the TEP may include a solvent or adjuvant which results in additive or synergistic toxicity.

The Agency is aware that additional data on pendimethalin are available for the European Food Safety Authority reports (EFSA, 2006). It is recomm ended that any applicable data generated for the European review process be submitted to EPA.

8 A Tier II study is required. The DCI will provide that a Tier I plant study ma y be conducted in lieu of a Tier II study with the understanding that any adverse effects observed by the Tier I study would necessitate conduct and submission of a Tier II study as well.43 Table 8 .2 lists the status of the ecological effects data requirements for pendimethalin

.

Table 8 .2. Ecological E ffects Data Requirements for Pendimethalin

.

Data Requirement Does EPA
Have
Data To Satisfy

This Requirement? Bibliographic Citation (MRID) Must Additional
Data Be
Submitted
Under FIFRA

3(c)(2)(B)?

§158.630 TERRESTRIAL ORGANISM TESTING

850.2100 Acute Avian Oral, Quail/Duck/Passerine Partially 00059739 Yes 1

850.2200 Acute Avian Diet, Quail Yes 00026675 No

850.2200 Acute Avian Diet, Duck Yes 00026674 No 850.2300 Avian Reproduction Quail Yes 44907602 No 850.2300 Avian Reproduction Duck Yes 44907601 No

§158.630 AQUATIC ORGANISM TESTING

850.1075 Acute Fish Toxicity Bluegill Yes 00046291 No

850.1075 Acute Fish Toxicity
Rainbow Trout Yes 00046291 No

Non

- Guideline Acute Fish Toxicity (TEP) Yes 00046292 No

850.1010 Acute Aquatic
Invertebrate Yes 00153772 No

Non

- Guideline Acute Aquatic Invertebrate (TEP) Yes 00059738 No

850.1075 Acute Est/Mar Toxicity
Fish Yes 00131774 No

850.1075 Acute Est/Mar Toxicity Fish (TEP) Yes 00131774 No

850.1035 Acute Est/Mar Toxicity Shrimp Yes 00131775 No

850.1035 Acute Est/Mar Toxicity Shrimp (TEP) Yes 00131775 No

850.1025 Acute Est/Mar Toxicity
Mollusk Yes 00131772 No44 Table 8 .2. Ecological E ffects Data Requirements for Pendimethalin

.

Data Requirement Does EPA
Have
Data To Satisfy

This Requirement? Bibliographic Citation (MRID) Must Additional
Data Be
Submitted
Under FIFRA

3(c)(2)(B)?

850.1025 Acute Est/Mar Toxicity Mollusk (TEP) Yes 00131772 No

850.1400 Early Life Stage Fish (freshwater) Yes 00029791 No

850.1400 Early Life Stage Fish (salwater) No N/A Yes 2

850.1300 Life Cycle Aquatic Invertebrate (freshwater) Yes 00100504 No

850.1350 Life Cycle Aquatic Invertebrate (saltwater) No N/A Yes 3

850.1500 Life Cycle Freshwater
Fish Yes 00037940 No

850.1730 Bioaccumulation in Fish Yes 00156726,
00158235 No

OCSPP 850.1760 (in prep.), 850.1770 (in prep.) and 850.1780 (in prep.) Whole sediment:
chronic invertebrates freshwater &
marine Partially 47891601 Yes 4
, 5

850.1020 Aquatic Invertebrate Acute Toxicity (Hyalella) No N/A No

§158.660 PLANT PROTECTION TESTING

850.4100 Seed Germ, Seedling Emergence Yes 42372201,
42372202 Yes 6

850.4150 Vegetative Vigor Yes 42372203 Yes 7

850.4400, 850.5400 Aquatic Plant
Growth Yes 42137101,
42372205

, 42372204,

42372206

42372207 No

§158.490 INSECT POLLINATOR TESTING

850.3020 Honey Bee Acute Contact Yes 0009980 No45 850.3030 Honey Bee Residue on Foliage No N/A No

850.3040 Field Test for Pollinators No N/A No

N/A = Not applicable because no citation is available.

1 Data are needed for a passerine species. The registrant should submit a protocol prior to conducting this study.

2 Data are needed for a saltwater fish species. Without this data EFED will use an acute

- to

- chronic ratio that may represent a more conservati ve value.

3 Data are needed for a saltwater invertebrate species. Without this data EFED will use an acute

- to

chronic ratio that may represent a more conservative value.

4 Until the final OCSPP guidelines for chronic sediment toxicity tests are published, t he registrant should submit a protocol to EFED for approval prior to test initiation.

5 A chronic test is required. The DCI will provide that an acute sediment toxicity study may be conducted in lieu of a chronic study with the understanding that any adve rse effects observed by the acute study would necessitate conduct and submission of a chronic study as well.

6 Tier II tests needed if a tested terrestrial species exhibits a statistically significant detrimental effect in the Tier I study.

7 Tier II tests needed if a tested aquatic species exhibits a statistically significant detrimental effect in a Tier I study.

8 Literature Cited

Arnot, J.A. and F.A.P.C. Gobas. 2004. A food web bioaccumulation model for organic chemicals in aquatic ecosystems. Environmental Toxicology and Chemistry, 23 (10) : 2343

- 2355.

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the
EPA food

- chain (Kenaga) nomogram, an instrument for estimating pesticide residues on plants. Environ. Tox. Chem. 13:1383

- 1391.

Hoerger, F. and E. E. Kenaga. 1972. Pesticide Residues on Plants: Correlation of Representative Data as a Basis for Estimation of the ir Magnitude in the Environment. In F. Coulston and F. Korte, eds., Environmental Quality and Safety: Chemistry, Toxicology, and Technology, Georg Thieme Publ., Stuttgart, West Germany, pp. 9

- 28.

Majewski, M.S. and P.D. Capel, 1995. Pesticides in the At mosphere. Distribution, Trends, and Governing Factors. Ann Arbor Press, Chelsea, Mich., p. 160.

UCDAVIS. COOPERATIVE EXTENSION. UNIVERSITY OF CALIFORNIA. Kiwifruit Production in California. Accessed on March 7, 2012 @ http://sfp.ucdavis.edu/pubs/brochures/kiwi.html

.46 USEPA. 2002. Technical Basis for the derivation of Equilibrium Partitioning Sediment Guidelines (ESGs) for the Protection of Benthic Organisms: No nionic Organics [Draft].
EPA Document No. 822R02041. October 2002.

U.S. EPA. 2007. Ecological Risk Assessment for the Proposed Use of Pendimethalin on Artichoke, Asparagus, Brassica 5a, and Grapes. Environmental Fate and Effects
Division. Office of P esticide Programs. October 31, 2007. DP334069.

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004

U.S. EPA. 2009. Risks of Pendimethalin Use to Federally Threatened California Red

- Legged Frog (Rana aurora draytonii). Pesticide Effects Determination. Environmental Fate and
Effects Division. Office of Pesticide Programs. October 31, 2007. http://www.epa.gov/espp/litstatus/effects/redleg

- frog/index.html#pendimethalin

U.S. EPA. 2010. Ecological Risk Assessment for the Pendimethalin Section 3 New Use on
Edamame and Cool

- and Warm

- Season Forage Grass.

USEPA. 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of Research and Development, Washington, D.C. EPA/630/R

- 95 /002F. April 1998. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759

.

Di Toro, D. M., Zarba, C. S., Hansen, D. J., Berry,W. J., Swartz, R. C., Cowan, C. E., Pavlou, S. P., Al len, H. E., Thomas, N. A. and Paquin, P. R. 1991. Technical basis for establishing
sediment quality criteria for nonionic organic chemicals using equilibrium partitioning.
Environmental Toxicology and Chemistry. 10:1541

- 1583.

9 Fate and Ecotoxicity Bibliography47 Pendimethalin Fate Bibliography

Note to Reviewer There are many 5 Year soil dissipation and residue studies in our folders that are not captured by OPPIN. Authors are Roman, Tondreau and others about 1979 all under one MRID 00046795. Most are invalid

See 2037406, 2037408, 2037409, 2037422, 2037423, 2037424, 2037425, 2037426, 2037427, 2037428, 2037429, 2037430, 2037431, 2037432, 2037433

161

- 1 Hydrolysis

MRID Citation Reference

46287 See 106777
below Zulalian, J.; Eisner, S.K. (1974) Prowl Herbicide: A Study on the Behavior of 14?C

Labeled CL 92,553 in an Hydrolytic Environ

- ment: Project No. 2

- 463. (Unpublished study received Sep 27, 1974 under 5F1556; submitted by American Cyanamid Co.,
Prince

- ton, N.J.; CDL:094674

- A)

46296 2037434 Zulalian, J.; Fasinski, R.; Eisner, S.K. (1973) CL 92,553: Metabo

- lism VII. Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) on Exposure to Sunlight in Water and on Glass and Soil Surfaces: Report No. 2

- 463. (Unpublished study received Sep 27, 1974 u nder 5F1556; prepared by American Cyanamid Co., Princeton, N.J.;
CDL:094673

- R)

109914 See above Zulalian, J.; Fasinski, R.; Eisner, S. (1973) CL 92,553: Metabo

- lism VII. Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) on Exposure to Sunlight in Wa ter and on Glass and Soil Surfaces: PD

- M 10:912

- 958. (Unpublished study received on unknown date under 4G1451; submitted by American Cyanamid Co., Princeton, NJ;
CDL:094672

- D)

106777 2037438 Study in Hydrolytic environment

161

- 2 Photodegradatio n
- water

MRID Citation Reference

153763 2037455 Sanders, P. (1985) Prowl Herbicide, Pendimethalin (AC 92,553): Photodegradation in Water: Project No. 0166: Report No. PD

- M Volume 22

- 36. Unpublished study prepared by American Cyanamid Co. 32 p.

43808201 Mentioned in RED chapter Ta, C. (1995) Aqueous Photolysis of AC 92,553: Lab Project Number: ENV 95

- 028: E

- 95

- 04. Unpublished study prepared by American Cyanamid Co. 99 p.

05001076 2037439 Open lit on photodecomposition

– 11 herbibcides

46296 Zulalian, J.; Fasinski, R.; Eisner, S.K. (1973) CL 92,553: Metabo

- lism VII. Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) on Exposure to Sunlight in

Water and on Glass and Soil Surfaces: Report No. 2

- 463. (Unpublished study received Sep 27, 1974 under 5F1556; prepared by American Cyanamid Co., Princeton, N.J.; CDL:094673

- R)

161

- 3 Photodegradation

- soil48 MRID Citation Reference

46296 2037434 Zulalian, J.; Fasinski, R.; Eisner, S.K. (1973) CL 92,553: Metabo

- lism VII. Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) on Exposure to Sunlight in Water and on Glass and Soil Surfaces: Report No. 2

- 463. (Unpublished study received Sep 27,
1974 u nder 5F1556; prepared by American Cyanamid Co., Princeton, N.J.;
CDL:094673

- R)

109914 See above Zulalian, J.; Fasinski, R.; Eisner, S. (1973) CL 92,553: Metabo

- lism VII. Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) on Exposure to Sunlight in Wa ter and
on Glass and Soil Surfaces: PD

- M 10:912

- 958. (Unpublished study received on unknown date under 4G1451; submitted by American Cyanamid Co., Princeton, NJ;
CDL:094672

- D)

153764 2037456 Mangels, G. (1985) Prowl Herbicide, Pendimethalin (AC 92,553): Photodegradation on Soil: Project No. 0166: Report No. PD

- M Volume 22

- 35. Unpublished study prepared by American Cyanamid Co. 27 p.

162

- 1 Aerobic soil metabolism

MRID Citation Referenc e

46282 2037414 Summary
2037315 Barringer, D.F., Jr.; Haugwitz, M.I.; Eisner, S.K. (1974) CL 92,553: Metabolism XIII. The Behavior of CL 92,553 (Prowl Herbicide) in Soil, Part III. Anaerobic Studies: Project No. 2

- 463. (Unpublished study received Sep 27, 1974 under 5F1556; submitted by American Cyanamid Co., Princeton, N.J.; CDL: 094475

- I)

40185104 2037461 Lavin, M.; Cranor, W. (1987) Aerobic Soil Metabolism of [Carbon 14]

- Pendimethalin: Lab. Rept. No. 33731. Unpublished study pre

- pared by Analytical
Bio

- Chemistry Laboratories, Inc. 677 p.

162

- 2 Anaerobic soil metabolism

MRID Citation Reference

151795 or
137706 2037518 pg

2 Mangels, G. (1984) Prowl Herbicide, Pendimethalin (CL 92,553): Anaerobic Metabolilsm in Soil from a Rice Field: Project NO. 0470: Rept. No. PD

- M Vol. 21

- 2.1. Unpublished study prepared by American Cyanamid Co. 29 p.

40185105 2037462 Lavin, M.; Cranor, W. (1987) Anaerobic Soil Metabolism of [Carbon 14]

- Pendimethalin: Lab. Rept. No. 33732. Unpublished study pre

- pared by Analytical
Bio

- Chemistry Laboratories, Inc.

162

- 3 Anaerobic aquatic metab.

MRID Citation Reference

40813501 2037483 Sanders, P. (1988) Pendimethalin (AC 92,553): Anaerobic Aquatic De

- gradation in Soil from a Rice Field: Laboratory Project ID PD

- M

- 25

- 25. Unpublished study prepared by American Cyanamid Co. 53 p.

43154701 Response Mangels, G.; Ahmed, Z. (1994) Pendimethalin Registration Standard

-- Response to49 EFGWB Review. Unpublished study prepared by American Cyanamid Co. 88 p.

43154702 No DER but
summarized in

REDs
2038941 Mangels, G. (1991) Pendimethalin (AC 92, 553): Anaerobic Aquatic Degradatio n in Static Canadian Pond Water: Lab Project Number: PD

- M 28

- 5: E

- 89

- 30: 0466. Unpublished study prepared by American Cyanamid Co. 117 p.

162

- 4 or 835.4300 Aerobic aquatic metab.

MRID Citation Reference

47385201 2081628 Ebert, D. (2008) Degradation of Pendimethalin (BAS 455 H) in Water/Sediment Systems Under Aerobic Conditions: Final Repost. Project Number: 169996, 2004/1022517. Unpublished study prepared by BASF Aktiengesellschaft. 75 p.

163

- 1 Leach/adsorp/desorption

MRID Citation Reference

46288 2037416 Summary
2037315 Barringer, D.F., Jr.; Haugwitz, M.I.; Jakowlew, S.B.; et al. (1974) CL 92,553: A Study of the Leaching of CL 92,553 (Prowl Herbi

- cide) from Four Different Soil Types: Project No. 2

- 463. (Un

- published study received Sep 27, 1974 under 5F1556; submitted by American Cyanamid Co., Princeton, N.J.; CDL:094674

- B)

46289 2037417 Summary
2037315 O'Grodnick, J.S.; Dupre, G.D. (1974) Leaching Characteristics of ^14IC

- Prowl^(R)I and Its Degradation Products following Aging in Princeton Sandy Loam Soil under Greenhouse Conditions: Report No. 74003

- 1. (Unpublished study received Sep 27,
1974 under 5F15 56; prepared by Bio/dynamics, Inc., submitted by American Cyanamid Co., Princeton, N.J.; CDL:094674

- C)

46290 2037418 Summary
2037315 Dupre, G.D. (1974) Runoff Characteristics of ^14IC

- Prowl^(R)I Ap

- plied to Silt
Loam Soil under Greenhouse Conditions: R eport No. 74004. (Unpublished study received Sep 27, 1974 under 5F1556; prepared by Bio/dynamics, Inc., submitted by American Cyanamid Co., Princeton, N.J.; CDL:094674

- D)

46296 Zulalian, J.; Fasinski, R.; Eisner, S.K. (1973) CL 92,553: Metabo

- lism VII. Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) on Exposure to Sunlight in Water
and on Glass and Soil Surfaces : Report No. 2

- 463. (Unpublished study received Sep 27, 1974 under 5F1556; prepared by American Cyanamid Co., Princeton, N.J.;
CDL:094673

- R)

106777 Summary
2037315 American Cyanamid Co. (1974) Introduction to Environmental Chem

- istry Studies with Prowl (AC 92,553). (Compilation; unpublished study received on unknown date under 5G1567; CDL:094279

- A; 094280; 094281; 094282)

106782 2037310 Zulalian, J.; Godney, R.; Fasinski, R. (1973) CL 92,553

-- Metabo

- lism V: Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) in Soil: PD

- M 10:837

- 911. (Unpublished study received on un

- known date under 4G1451; submitted by American Cyanamid Co., Princeton, NJ; CDL:094672

- B)

153765 2037457 Mangels, G. (1985) Prowl Herbicide, Pendimethalin (AC 92,553): Adsorption/Desorption Studies: Project No. 0166: Report No. PD

- M Volume 22

- 37. Unpublished study prepared by American Cyanamid Co. 76 p.

43041 901 Mangels, G. (1993) Pendimethalin (AC 92,553): Adsorption/Desorption on Japanese Soils: Lab Project Number: PD/M/28/11: PD/M: E/90/3. Unpublished study prepared by American Cyanamid Co. 37 p.50 163

- 2 Volatility

- lab

MRID Citation Reference

153766 2037458 Sanders, P. (1985) Prowl Herbicide, Pendimethalin (AC 92,553): Volatilization from Soil: Project No. 0166: Report No. PD

- M Volume 22

- 38. Unpublished study prepared by American Cyanamid Co. 28 p.

164

- 1 Terrestrial field dissipation

MRID Citation Reference

24857 Kennedy, J.M.; Talbert, R.E.; Fischer, B. (1974) ?Dinitroaniline Herbicides: Their Persistence on the Soil Surface, Residual Ac

- tivity, and Relative Crop Tolerance|. (Unpublished study re

- ceived 1975 under 2G1285; prepared by Univ. of Arkansas, Agri

- cul tural Experiment Station, submitted by Union Carbide Agricul

- tural Products Co., Ambler, Pa.; CDL:095154

- E)

26872 Moyer, M.; Potts, C.; Devine, J.M.; et al. (1975) Prowl^(R)I(CL 92,553): Determination of CL 92,553 ?N

- (1

- Ethylpropyl)

- 3,4

- di

- methyl

- 2,6

- dinitrobenzenamine| and Sencor ?4

- Amino

- 6

- t

- butyl

- 3

- (methylthio)

- 1,2,4

- triazin

5

- one| in Soil: Report No. C

- 859. (Unpublished study received Nov 20, 1975 under 6F1704; submitted by American Cyanamid Co., Princeton, N.J.; CDL:094647

- H)

26873 Potts, C.R.; Laporta, M.M.; Devine, J.; et al. (1975) Prowl^(R)I (CL 92,553): Determination of CL 92,553 ?N

- (1

- Ethylpropyl)

- 3,4

- dimethyl

- 2,6

- dinitrobenzenamine| and Sencor ?4

- Amino

- 6

- t

- butyl

- 3

- (methylthio)

- 1,2,4

- triazin

5(4H)

- one| in Soil: Report No. C

- 801. (Unpublished study received Nov 20, 1975

u nder 6F1704; submitted by American Cyanamid Co., Princeton, N.J.; CDL:
094647

- I)

46281 2037413 Summary
2037315 Barringer, D.F., Jr.; Zulalian, J.; Fisner, S.K. (1974) CL 92,553: Metabolism XI. The Behavior of CL 92,553 (Prowl Herbicide) in Soil, Part II . A 16

- Month Field

Exposure Study: Project No. 2

- 463. (Unpublished study received Sep 27, 1974 under 5F1556; submitted by American Cyanamid Co., Princeton, N.J.; CDL:
094475

- H)

46294 Wyckoff, J.C.; Nzewi, G.I.; Roberts, W.W.; et al. (1974) ?Residue Stu dy of Prowl, Atrazine, Bladex and Banvel in Soil|: Report No. C

- 518. (Reports by various sources; unpublished study in

- cluding report no. C

- 517, received Sep 27, 1974 under 5F1556; submitted by American Cyanamid Co., Princeton, N.J.; CDL:
094674

- N)

4629 5 2037420 Summary
2037315 Nzewi, G.I.; Tondreau, R.E.; Jakowlew, S.; et al. (1974) ?Residue Study of Prowl in Soil|: Report No. C

- 473. (Reports by various sources; unpublished study including report nos. C

- 476, C

- 477, C

- 475..., received Sep 27, 1974 under 5F1556; submitted by Amer

- ican Cyanamid Co., Princeton, N.J.; CDL:094673

- C)

106782 Summary
2037315

2037413 Zulalian, J.; Godney, R.; Fasinski, R. (1973) CL 92,553

-- Metabo

- lism V: Fate of
Carbon

- 14 Labeled CL 92,553 (Prowl Herbicide) in Soil: PD

- M 10:837

- 911. (Unpublished study received on un

- known date under 4G1451; submitted by American Cyanamid Co., Princet on, NJ; CDL:094672

- B)

106798 Summary
2037315 American Cyanamid Co. (1978) Amounts of Residues of Prowl, Its Metabolite (CL 202,347), Metribuzin (Sencor or Lexone) and Eptam in Soil. (Compilation; unpublished study received Oct 5, 1978 under 241

- 243; CDL :097435

- A)

106805 Devine, J.; Kust, C.; Moyer, M.; et al. (1975) Prowl (CL 92,553): Determination of51 CL 92,553 ... and Sencor ... in Soil. Indi

- ana.: Report No. C

- 859. (Unpublished study received Nov 14, 1975 under 6F1704; submitted by American Cyanami d Co.,
Prince

- ton, NJ; CDL:097956

- E)

106806 2037454 Devine, J.; Kust, C.; Potts, C.; et al. (1975) Prowl (CL 92,553): Determination of CL 92,553 ... and Sencor ... in Soil. Kan

- sas. 1974: Report No. C

- 801. (Unpublished study received Nov 14, 1975 und er 6F1704; submitted by American Cyanamid Co., Princeton, NJ; CDL:097956

- F)

129090 American Cyanamid Co. (1979) ?Residue of Prowl Herbicide in Soil|. (Compilation; unpublished study received May 17, 1979 under 241

- 243;
CDL:238510

- D)

5001077 Summary
2037315 Parochetti, J.V.; Dec, G.W., Jr.; Burt, G.W. (1976) Volatility of eleven dinitroaniline herbicides. Weed Science 24(6):529

- 532.

41725204 2037464 Steller, W.; Smyth, M. (1990) Pendimethalin (AC 92,553): Residues of AC 92,553 in Soil (Postemergence, Sandy Loam) Kerman, Cali

- fornia

-- 1988: Lab Project
Number: C

- 3280. Unpublished study prepared by American Cyanamid Co. 90 p.

41725205 Sreller, W.; Sm yth, M. (1990) Pendimethalin (AC 92,553): Residues of AC92, 553 in Soil (Post

- emergence, Sandy) Brawley, California 1988: Lab Project Number: C

3281. Unpublished study prepared by American Cyanamid Co. 65 p.

41725206 Smyth, M; Koch, D.; Smith, J. (1990) Pendimethalin (AC 92, 553): Freezer Stability in Soil: Lab Project Number: C

- 3467. Unpub

- lished study prepared by American Cyanamid Co. and Analytical Biochemistry Labs, Inc. 281 p.

43154701 Mangels, G.; Ahmed, Z. ( 1994) Pendimethalin Registration Standard

-- Response to EFGWB Review. Unpublished study prepared by American Cyanamid Co. 88 p.

45136801 2002727 Kukel, C. (2000) CL 92553 (Pendimethalin): Rate of Dissipation of CL 92553
Residues in Air and Soil After Tr eatment with Prowl 3.3 EC Herbicide Applied

Pre

- Plant Incorporated (PPI) to Soybeans in Indiana, U.S: Lab Project Number: PR98IN01: A011.294: A011.310. Unpublished study prepared by American Cyanamid Company, Heartland Technologies, H.E.R.A.C., Inc. and Ma xim Technologies. 207 p.

45136802 2002728 Kukel, C. (2000) CL 92553 (Pendimethalin): Rate of Dissipation of CL 92553 Residues in Air and Soil After Treatment with Prowl 3.3 EC Herbicide Applied

Pre

- Emergence (PE) to Cotton in Louisiana, U.S: Lab Projec t Number: PR98LA02: A011.295: A011.311. Unpublished study prepared by American Cyanamid Company, H.E.R.A.C., Inc. and Maxim Technologies. 214 p.

45364705 2002730 or
2002732 Horton, W. (2001) CL 92553 (Pendimethalin): Comparison of the Rate of Dissipation of CL 92553 Residues in Soil Following a Single Preemergent Application of Either Prowl 3.3 EC Herbicide or Prowl 3.8 CS Herbicide to Cotton in Mississippi: Lab Project Numbe r: RES 00

- 040: PR98MS01: M 820.04. Unpublished study prepared by BASF Agro Research Corporation and Maxim Technologies, Inc. 199 p.

45364706 2002729 Horton, W. (2001) CL 92553 (Pendimethalin): Comparison of the Rate of Dissipation of CL 92553 Residues in Soil Following a Single Pre

- Plant Incorporation of Either Prowl 3.3 EC Herbicide or Prowl 3.8 CS Herbicide to Soybeans in Indiana: Lab Project Number: RES 00

- 039: PR9907: PR9907IN01. Unpublished study prepared by BASF Agro Research Corporation. 198 p.

164

- 2 Aquatic field dissipation

MRID Citation Reference52 29031 Tondreau, R.E. (1973) CL 92,553: N

- (1

- Ethylpropyl)

- 2,6

- dinitro

- 3,4

- xylidine Residues in Soil: Report No. C

- 355. Includes method M

- 388 dated Oct 25, 1973. (Unpublished study received on un

- known date under 4G1451; submitted by American Cyanamid Co., Princ eton, N.J.; CDL:093869

- Q)

29032 2037407 Bodnarchuk, D.; Moyer, M.; Tondreau, R.E.; et al. (1973) Prowl: Determination of CL 92,553...Residues in Soil (Waseca, Minneso

- ta) Treated by Pre

- emergence Spray: Report No. C

- 400. Includes method M

- 437 dated Oct 25, 1973. (Unpublished study received on unknown date under 4G1451; submitted by American Cy anamid Co., Princeton, N.J.; CDL:093869

- R)

31976 Boughton, P.J.; Benson, G.L.; Moyer, M.; et al. (1975) Residue Sum

- maries

-- Pay

Off Tobacco Sucker Control Agent. (Unpublished study received Mar 18, 1975
under 241

- 247; prepared in coopera

- tion with U.S . Agricultural Research Service and others, submit

- ted by American Cyanamid Co., Princeton, N.J.; CDL:050910

- D)

67293 Summary
2037315 Marei, A.H.; Haugwitz, M.I.; Eisner, S.K. (1974) CL 92,553: Metabo

- lism: XII. Residual Radioactivity in Rice Grain and Plants Grown in Soil Treated with
Carbon

- 14 CL 92,553: PD

- M 11:376

- 416. Fi

- nal rept. (Unpublished study received Aug 25, 1980 under 241

- 243; submitted by American Cyanamid Co., Princeton, N.J.; CDL: 099565

- K)

41245601 2037465 Manual, A. (1980) Analysis for Residues of Prowl in Soil and in Water from Prowl Treated Rice Fields: Report No. CY 17. Unpub

- lished study prepared by American Cyanamid Co. 114 p.

44527601
and 602 2002731 Leonard, R.; Xu, B.; Cenni, M. et al. (1997) D issipation of CL 92,553 Residues in Water, Soil and Sediment from a PROWL 3.3 EC Herbicide Treated Rice Field: Lab Project Number: RES 95

- 195: RES 96

- 057: RES 96

- 112. Unpublished study prepared by Centre Analytical Labs., Inc., American Cyanamid Co., and M axim Technologies, Inc. 302 p. {OPPTS 840.1200}

165

- 0 Accumulation Studies

-- General

MRID Citation Reference

46293 2037419 Kapoor, I.P.; Barringer, D.F., Jr.; Haugwitz, M.I.; et al. (1974) Prowl Herbicide: Metabolism X. Isolation, Identification, and Characterization of CL 92, 553 and Its Metabolites in Fish and Its Aquatic Environment: Project No. 2

- 463. (Unpublished study re ceived Sep 27, 1974 under 5F1556; prepared in cooperation with Bionomics EG&G, Inc., submitted by American Cyanamid Co., Princeton, N.J.;
CDL:094674

- G)

165

- 1 Confined rotational crop

MRID Citation Reference

41806801 2037466 Lee, T. (1989) Pendimethalin (CL 92,553): Confined Accumulation studies of
Carbon

- 14 Labeled Cl 92,553 in Lettuce, Wheat, Carrot Radishes, and Snap Beans as Representative Rotational Crops (Princeton New Jersey): Lab Project Number:
CY 38: PD

- M 26

- 4: PD

- M 24

- 33. Unpublished study prepared by American Cyanamid Co. 210 p.53 43918601 Afzal, J. (1996) Pendimethalin (CL 92,553): Confined Accumulation Study of
Carbon

- 14 Labeled CL 92,553 in Lettuce, Radishes, and Wheat as Rotational Crops: Lab Project Number: MET 96

- 002: M94P553NC1: 95AASIFRF001. Unpublished study prepared by American Cya namid Co. and American Agricultural Services, Inc. 342 p.

165

- 4 Bioaccumulation in fish

MRID Citation Reference

158235 and
156726 2037459 Forbis, A.; Burgess, D.; Burnett, J. (1986) Uptake, Depuration and Bioconcentration of [Carbon

- 14]

- AC 92,553 by Bluegill Sunfish (Lepomis macrochirus): PD

- M Volume 23

- 17; ABC Final Report # 33408. Unpublished study prepared by Analytical Bio

- Chemistry Labo ratories, Inc. 276 p.

71124 McAllister, W.A.; Thompson, C.M.; Forbis, A.D.; et al. (1980) Resi

- due Accumulation Study in Crayfish (~Procambarus simulans~) with ^14IC

- CL 92,553 (Pendimethalin) under Static Conditions: Final Residue Accumulation Report # 25687. (Unpublished study rece ived Jan 22, 1981 under 241

- 243; prepared by Analytical Bio Chemistry Laboratories, Inc., submitted by American Cyanamid Co., Princeton, N.J.;
CDL:099889

- C)

Drift study

– 00029344= 2037410

Residues in Water 00071126, 00058834, and 00071129 = 2037437

Pendimethalin Ecotoxicity Bibliography

71

- 1 Avian Single Dose Oral Toxicity

MRID Citation Reference

59739 2037321 Fink, R. (1976) Final Report: Acute Oral LD50

-- Mallard Duck: Proj

- ect No.
130

- 110. (Unpublished study received 1976 under 241

- 243; prepared by Truslow Farms, Inc., submitted by American Cyanamid Co., Princeton, N.J.;
CDL:228391

- B)

71

- 2 Avian Dietary Toxicity

MRID Citation Reference

26674 or 52577 or
72900 2037317 Fink, R. (1973) Final Report: Eight

- Day Dietary LCI50^

-- Mallard Ducks: Project No. 362

- 138 . (Unpublished study received on un

- known date under 4G1451; prepared by Hazleton Laboratories, Inc., submitted by American Cyanamid Co., Princeton, N.J.; CDL:093868

- X)

26675 or 52578 or DER not Fink, R. (1973) Final Report: Eight

- Day Diet ary LCI50^

-- Bobwhite Quail:54 72899 located Project No. 362

- 137 . (Unpublished study received on un

- known date under 4G1451; prepared by Hazleton Laboratories, sub

- mitted by American Cyanamid Co., Princeton, N.J.; CDL:093868

- Y)

29791 DER not
located Shaffer, C.B. (1974) ?Toxicology Studies of Prowl Herbicide|. (Un

- published study received Dec 21, 1974 under 5G1580; submitted by American Cyanamid Co., Princeton, N.J.; CDL:094331

- A)

52577 2007317 Fink, R. (1973) Final Report: Eight

- Day Dietary LCI50^

-- Mallard Ducks: Project No. 362

- 138 . (Unpublished study received Sep 27, 1974 under 5F1556; prepared by Environmental Sciences Corp., submitted by American Cyanamid Co., Princeton, N.J.; CDL: 094232

- H)

52578 See 26675
above Fink, R. (1973) Final Report: Eight

- Day Dietary LC50

-- Bobwhite Quail: Project No. 362

- 137 . (Unpublished study received Sep 27, 1974 under 5F1556; prepared by Environmental Sciences Corp., submitted by American Cyanamid Co., Princeton, N.J.; CDL: 094232

- I)

71

- 4 Avian Reproduction

MRID Citation Reference

44907601 2037344 Beavers, J.; Foster, J.; Jaber, M. et al. (1996) Reproduction Study with AC 92553 Technical in Mallard (Anas platyrhynchos): Lab Project Number: 954

- 93

- 195: 130

- 171: TAN 95

- 004. Unpublished study prepared by Wildlife International, Ltd. 270 p. {OPPTS 850.2300}

44907602 2037345 Beavers, J.; Foste r, J.; Jaber, M. et al. (1996) Reproduction Study with AC 92553 Technical in the Northern Bobwhite (Colinus virginianus): Lab Project
Number: 954

- 93

- 197: 130

- 170: TAN 95

- 004. Unpublished study prepared by Wildlife International, Ltd. 274 p.

72

- 1 Ac ute Toxicity to Freshwater Fish

MRID Citation Reference

106764 or 37778

or 46291 2037331
2037320 Sleight, B. (1973) Acute Toxicity of AC

- 92553 to Bluegill (Lepomis macrochirus), Rainbow Trout (Salmo gairdneri) and Channel Cat

- Fish (Ictaluras punctatus). (Unpublished study received on unknown date under 5G1567; prepared by Bionomics, Inc., sub

- mitted by American Cyanamid Co., Princeton, NJ; CDL:094287

- E)

131773 2037330 LeBlanc, G.; Sousa, J. (1983) Acute Toxicity of AC 92,553 to Chan

- nel Catfish ...: Report #BW

- 83

- 2

- 1361. (Unpublished study re

- ceived Oct 28,
1983 under 241

- 243; prepared by EG & G Bionomics, submitted by American Cyanamid Co., Princeton, NJ; CDL:251601

- C)

37778 See 106764
above Sleight, B.H., III (1972) Bioassay Report: Acute Toxicity of AC

- 92553 to Bluegill (?~Lepomis macrochirus~?), Rainbow Trout (?~Salmo gairdneri~?)55 and Ch annel Catfish (?~Ictaluras puncta~?

- ?~tus~?). (Unpublished study received on unknown date under 4G1451; prepared by Bionomics, Inc., submitted by American Cyanamid Co., Princeton, N.J.; CDL:093868

- W)

46291 2037320 Sleight, B.H., III (1972) Acute Toxicit y of AC

- 92553 to Bluegill (~Lepomis macrochirus~), Rainbow Trout (~Salmo gairdneri~) and Channel Catfish (~Ictaluras punctatus~). (Unpublished study received Sep 27, 1974 under 5F1556; prepared by Bionomics, Inc., submitted by American Cyanamid Co.,
Prince ton, N.J.; CDL: 094674

- E)

46292 or 37927? 2037318 Bentley, R.E. (1974) Acute Toxicity of Prowl^(TM)I 3E, Prowl^(TM)I 4E, and Avenge 2A

- S to Bluegill (~Lepomis macrochirus~) and Rainbow Trout (~Salmo gairdneri~). (Unpublished study re

- ceived Sep 27, 1974 under 5F1556; prepared by Bionomics EG&G, Inc., sub mitted by American Cyanamid Co., Princeton, N.J.; CDL: 094674

- F)

37927 2037318 Bentley, R.E. (1974) Acute Toxicity of Prowl^(TM)I 3E, Prowl^(TMI) 4E, and Avenge 2A

- S to Bluegill (?~Lepomis macrochirus?~) and Rainbow Trout (?~Salmo gairdneri?~). (Unpublis hed study re

- ceived Nov 14, 1975 under 6F1703; prepared by Bionomics, EG&G, Inc., submitted by American Cyanamid Co., Princeton, N.J.; CDL: 094732

- H)

72

- 2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

59738 2037322 LeBlanc, G.A. (1976) Acute Toxicity of Prowl to~Daphnia magna~. (Unpublished study received 1976 under 241

- 243; prepared by Bio

- nomics, EG&G, submitted by American Cyanamid Co., Princeton, N.J.; CDL:228391

- A)

71123 2037326 Thompson, C.M.; Griffen, J.; M cAllister, W.A. (1980) Acute Toxicity of AC 92,553 to the Freshwater Crayfish (Procambarus simulans): Static Acute Bioassay Final Report # 25725. (Unpublished study received Jan 22, 1981
under 241

- 243; prepared by Analytical Bio Chemistry Laboratories, Inc

., submitted by American Cyanamid Co., Princeton, N.J.; CDL:099889

- B)

153772 2037525 Forbis, A.; Georgie, L.; Burgess, D. (1985) Acute Toxicity of AC 92,553 4E to Daphnia magna: Static Acute Toxicity Report #33409. Unpublished study prepared by Analytical Bio

- Chemistry Laboratories, Inc. 39 p.

72

- 3 Acute Toxicity to Estuarine/Marin e Organisms

MRID Citation Reference

131772 2037333 Ward, G. (1983) Acute Toxicity of AC 92,553 Technical and Formulat

- ed to Embryos

- larvae of Eastern Oysters ...: Report No. BP

- 83

- 6

- 65; Project No. R95. (Unpublished study received Oct 28, 1983 under 241

- 1243; prepared by EG & G Bionomics, submitted by Am erican Cyanamid Co., Princeton, NJ;
CDL:251601

- A)

131774 2037334 Ward, G.; Shuba, P. (1983) Acute Toxicity of AC 92,553 Technical and Formulation to Sheepshead Minnows ...: Report No. BP

- 83

- 3

- 39; Project No. R95. (Unpublished study received Oct 28, 1983 under 241

- 243; prepared by EG & G Bionomics, submitted by American Cyanamid Co., Princeton, NJ;
CDL:251601

- E)56 131775 2037335 Ward, G.; Shuba, P. (1983) Acute Toxicity of AC 92,553 Technical and Formulation to Pink Shrimp ...: Report No. BP

- 83

- 1

- 5; Pro

- ject No. R95. (Unpublished study received Oct 28, 1983 under 241

- 24 3; prepared by EG & G Bionomics, submitted by American Cy

- anamid Co., Princeton, NJ;
CDL:251601

- G)

72

- 4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID Citation Reference

29791 Shaffer, C.B. (1974) ?Toxicology Studies of Prowl Herbicide|. (Un

- published study received Dec 21, 1974 under 5G1580; submitted by American Cyanamid Co., Princeton, N.J.; CDL:094331

- A)

37940 2037319 EG& G, Bionomics (1975?) Chronic Toxicity of CL

- 92,553 to the Fat

- head Minnow (Pimephales promelas). (Unpublished study received Sep 8, 1977
under 241

- 243; submitted by American Cyanamid Co., Princeton, N.J.;
CDL:096342

- A)

100504 2037323
2037329 Graney, R.L . (1981) The Chronic (21 Day) Toxicity of AC 92,553 to ?~Daphnia magna~Straus: Project No. 5179. (Unpublished study received Apr 20, 1982 under 241

- 243; prepared by Biospherics, Inc., submitted by American Cyanamid Co., Princeton, N.J.; CDL: 247299

- A)

15 8305 Letter Sauter, S. (1976) Letter sent to J. Wyckoff dated Aug 3, 1976: Chronic exposure of fathead minnows to Prowl. 6 p.

106819 Letter Sauter, S. (1978 ) Letter sent to R. Barron dated Feb 20, 1978 ? Chronic toxicity test with fathead minnows and CL

- 92,553|. (Unpublished study received Mar 22, 1978 under 241

- 243; prepared by EG & G Bionomics, submitted by American Cyanamid Co., Prince

- ton, NJ; CDL:233264

- A)

72

- 5 Life cycle fish

MRID Citation Reference

37940 2037319 EG&G, Bionomics (1975?) Chronic Toxicity of CL

- 92,553 to the Fat

- head Minnow (Pimephales promelas). (Unpublished study received Sep 8, 1977
under 241

- 243; submitted by American Cyanamid Co., Princeton, N.J.;
CDL:096342

- A)

58831 2037324 Sleight, B.H., III (1976) Letter sent to John Wyckoff dated Apr 20, 1976 (Progress report on chronic exposure of fathead minnows to CL

- 92,553). (Unpublished study received Jun 1, 1976 under 241

- 243; prepared by EG&G, Bionomics, submitted by American Cyanamid Co., Princeton, N.J.;
CDL:224592

- A)

58833 2037325 Sleight, B.H., III (1976) Letter sent to John Wyckoff dated May 21, 1976 ?Raw data for water samples from fathead minnow chronic ex

- posure study with Prowl|. (Unpublished study received Jun 1, 1976 under 241

- 243; prepared by EG&G, Bionomics, submitted by American Cyanamid Co., Princeton, N.J.;
CDL:224592

- C)

72

- 6 Aquatic org. accumulation57 MRID Citation Reference

156726 2037526 Forbis, A.; Burgess, D.; Burnett, J. (1986) Uptake, Depuration and Bioconcentration of [Carbon

- 14]

- AC 92,553 by Bluegill Sunfish (Lepomis macrochirus): Final Report #33408. Unpublished study prepared by Analytical
Bio

- Chemistry Laboratories, Inc. 277 p.

123

- 1 Seed germination/seedling emergence and vegitative vigor

MRID Citation Reference

42372201 2037337 Chetram, R.; Gagne, J. (1992) A Tier 2 Plant Phytotoxicity Study for Seedling Emergence Using AC 92,553: Pendimethalin: Lab Project Number: BL91

- 453. Unpublished study prepared by American Cyanamid Comp. and Pan

Agricultural Laboratories, Inc. 243 p.

423 72202 2037338 White, T.; Gagne, J. (1992) A Tier 2 Plant Phytoxicity Study for Seed Germination Using AC 92,553: Pendimethalin: Lab Project Number: BL91

- 471. Unpublished study prepared by American Cyanamid Comp. and Pan

Agricultural Laboratories, Inc. 131 p.

42372203 2037339 Canez, V; Gagne, J. (1992) A Tier 2 Plant Phytoxicity Study for Vegetative Vigor Using AC 92,553: Pendimethalin: Lab Project Number: BL91

- 454. Unpublished study prepared by American Cyanamid Comp. and Pan

Agricultural Laboratories, In c. 212 p.

123

- 2 Aquatic plant growth

MRID Citation Reference

42137101 No DER
See 2037379 or
2037381 Hughes, J.; Alexander, M.; Wisk, J. (1991) Effect of AC 92,553 on Growth of Duckweed, Lemna gibba: Lab Project Number: B400

- 31

- 1. Unpublished study prepared by Malcolm Pirnie, Inc. 60 p.

42372204 2037340 Hughes, J.; Alexander, M.; Wisk, J. (1992) Effect of AC 92,553 on Growth of the Green Alga, Selenastrum Capricornutum: Pendimethalin: Lab Project
Number: B400

- 32

- 1. Unpublished study prepared by American Cyanamid Comp. and Malcolm Pirnie, Inc. 58 p.

4237 2205 2037341 Hughes, J.; Alexander, M.; Wisk, J. (1992) Effect of AC 92,553 on Growth of the Marine Diatom, Skeletonema Costatum: Pendimethalin: Lab Project
Number: B400

- 32

- 4. Unpublished study prepared by American Cyanamid Comp. and Malcolm Pirnie, Inc. 5 3 p.

42372206 2037342 Hughes, J.; Alexander, M.; Wisk, J. (1992) Effect of AC 92,553 on Growth of the Freshwater Diatom, Navicula Pelliculosa: Pendimethalin: Lab Project
Number: B400

- 32

- 3. Unpublished study prepared by American Cyanamid Comp. and Malcol m Pirnie, Inc. 53 p.

42372207 2037343 Hughes, J.; Alexander, M.; Wisk, J. (1992) Effect of AC 92,553 on Growth of
the Blue

- Green Alga, Anabaena Flos

- Aquae: Pendimethalin: Lab Project
Number: B400

- 32

- 2. Unpublished study prepared by American Cyanamid Comp . and Malcolm Pirnie, Inc. 60 p.58 47954502 Open lit Ma, J.; Liang, W.; Xu, L.; et al. (2000) Acute Toxicity of 33 Herbicides to the Green Alga Chlorella pyrenoidosa. Bulletin of Environmental Contamination and Toxicology 66:536

- 541.

47954503 Open lit Ma, J. (2001) Differential Sensitivity to 30 Herbicides Among Populations of Two Green Algae Scenedesmus obliquus and Chlorella pyrenoidosa. Bulletin of Environmental Contamination and Toxicology 68:275

- 281.

47954504 Open lit Ma, J.; Xu, L.; Wang, S.; et al. (2001) Toxicity of 40 Herbicides to the Green Alga Chlorella vulgaris. Exotoxicology and Environmental Safety 51:128

- 132.

47954505 Open lit Ma, J.; Lin, F.; Wang, S.; et al. (2004) Acute Toxicity Assessment of 20 Herbicides to the Green Alga Scenedesm us quadricauda (Turp.) Breb. Bulletin of Environmental Contamination and Toxicology 72: 1164

- 1171.

141

- 1 Honeybee Toxicity

51271 or
108773 2037332 Atkins, E.L. (1974) Letter sent to A.J. Tafuro dated May 20, 1974 ?Toxicity of Prowl to honeybees|. (Unpubl ished study received Sep 27, 1974 under 5F1556; prepared by Univ. of California

-- Riverside, Citrus Research Center and Agricultural Experiment Station, Dept. of Entomology, submitted by American Cyanamid Co., Princeton, N.J.; CDL:094674

- M)

99890 2037327
2037328 Atkins et al at UCR Honeybee acute

850

- 1790 Chironomid Sediment Toxicity Test

47891601 scanning Backfisch, K. (2009) Chronic Toxicity of Pendimethalin (BAS 455 H) to the Non

Biting Midge Chironomus riparius: A Spiked Sediment Study. Project Number: 326800, 2008/1010543. Unpublished study prepared by BASF SE. 35 p.

Non Guideline

48298805 Open lit Mullin, C.; Frazier, M.; Frazier, J.; et al. (2010) High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health. PLoS ONE: 5(3): 1

- 19.

48261117 Open lit Gustavson, K.; Mohlenberg, F.; Schluter, L. (2003) Effects of Exposure Duration of Herbicides on Natural Stream Periphyton Communities and Recovery. Archives of Environmental Contamination and Toxicolog y 45(1): 48

- 58.

48033008 Open lit Kojima, H.; Katsura, E.; Takeuchi, S.; et al. (2004) Screening for Estrogen and Androgen Receptor Activities in 200 Pesticides by In Vitro Reporter Gene Assays Using Chinese Hamster Ovary Cells. Environmental Health Persp ectives 112(5):
524

- 531.

48033010 Open lit Nishihara, T.; Nishikawa, J.; Kanayama, T.; et al. (2000) Estrogenic Activities of 517 Chemicals by Yeast Two

- Hybrid Assay. Journal of Health Science 46(4): 282

- 298.

47164601 Moore, D.; Breton, R.; Rodney, S.; e t al. (2007) Generic Problem Formulation for California Red

Legged Frog. Project Number: 89320, 05232007. Unpublished study prepared by Cantox Environmental Inc. 87 p.

47164602 Holmes, C.; Vamshi, R. (2007) Data and Methodology Used for Spatial Analysis of California Red Legged Frog Observations and Proximate Land Cover Characteristics. Project Number: 3152007, WEI/252/03. Unpublished study prepared by Waterborne Environmental, Inc. (WEI). 19 p.59 Appendix A. PRD Data Request Justification Tables

The following proposed Data Call

- in tables include rationales for requiring the data requested in this problem formulation, explanations of the utility of the data, and explanations for how the data might impact risk assessment, following the format provided by PRD.

Guideline Number: 835.4100 Study Title: Aerobic Soil Metabolism Rationale for Requiring the Data

Currently the Agency has received one supplemental study on one soil type (MRID 40185104 ). Aerobic soil metabolism studies facilitate an understanding of a compound’s degradation in soil resulting from pesticide interaction with soil microorganisms in aerobic (oxygen

- rich) conditions in the laboratory. The fate of pendimethalin formed in or deposited on soil cannot be characterized without the requested data. The Agency is asking for a minimum environmental fate data set for the pendimethalin i n order to estimate aquatic and terrestrial exposure. Without these data, exposure estimates will be based on conservative assumptions. Per 40 CFR part 158, promulgated July 1, 2009, requires aerobic soil metabolism data for pesticide food and nonfood t errestrial uses. An acceptable soil is required per OCSPP guideline
835.4100. For transformation rate studies at least three additional soils should be used representing a range of relevant soils.
Aerobic soil metabolism studies facilitate an understandin g of a compound’s degradation in the soil under aerobic conditions in the laboratory. Depending on how quickly, to what extent, and to which transformation products the compound degrades, pendimethalin may or may not pose potential exposure concern.

Pra ctical Utility of the Data

How will the data be used? Aerobic soil metabolism data will facilitate a better understanding of pendimethalin in soil. Aerobic soil metabolism data on pendimethalin along with adsorption/desorption data, will allow for direct estimation of expected exposures resulting from use of this pesticide. In addition, these data will allow the Agency to assess the expected persiste nce of the pendimethalin in surface waters for both human health drinking water assessments and ecological risk assessments.

How could the data change the Agency’s decision or impact the Agency’s future decision

making?
If the rate of pendimethalin d egradation increases in aerobic soil conditions, then antibiotic resistance may be a public health risk of concern and additional use precautions and/or restrictions may be necessary.60 Study Title: Analytical Methods (and Associated Independent Laboratory Validations) for Residues in Water, Sediment, and Soil
Guideline Number: 835.6100 Study Substance: Pendimethalin Rationale for Requiring the Data Independently validated analytical methods for residues in water, sediment, and soil (environmental chemistry methods) submitted by the registrant are used to evaluate analyses described in submitted environmental fate and ecological effects studies. Submitted analytical methods are also used by various Federal, State, Tribal, and local

a gencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent laboratory validations for submitted analytical methods are necessary to
confirm that the methods are functional and to confirm the levels of detection and quantitation reported in registrant

prepared validations.

Use of pendimethalin may impact surface water quality due to runoff of rain water and drift of residues. This is especially true for poor ly draining soils, erodible soils, and soils with shallow ground water. Pendimethalin has a potential for reaching both surface water and aquatic sediment via runoff. Therefore, outside agencies may request analytical methods with which to monitor for pen dimethalin residues in water and in soil or sediment.

Practical Utility of the Data

How will the data be used? In the absence of independently validated environmental chemistry methods, submitted environmental fate and ecological effects data may not be reviewable and entities outside the Agency may lack chemical

- specific methods for analyses in environmental compartments. Independently validated environmental chemistry methods will be used to evaluate any newly submitted environmental fate and ecologica l effects data and will be made available for enforcement and monitoring purposes at the federal, state, and local levels.

How could the data impact the Agency’s future decision

- making? Without these required data, the fate of pendimethalin cannot be fully characterized and exposure to potentially toxic degradates cannot be quantified. The persistence of pendimethalin and potential degradates to which terrestrial and aquatic organisms will be exposed to is uncertain. In the absence of accep table data, conservative assumptions will be made regarding the potential for formation of pendimethalin degradates. Therefore, potential for risk to aquatic organisms may be overestimated and the use of pendimethalin might need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for pendimethalin which are

unneces sarily severe.

Guideline Numbers and Study Titles:

• Test Method 100.4 (OCSPP 850.1770, in prep.); Whole sediment: chronic invertebrates freshwater ( Hyalella azteca )

• Test Method 100.5 (OCSPP 850.1760, in prep.); Whole sediment: chronic invertebrates freshwater ( Chironomus dilutus ) US EPA 2001,61 • EPA 600/R

- 01/020 (OCSPP 850.1780, in prep.); Whole sediment: chronic invertebrates marine ( Leptocheirus plumulosus )

Rationale for Requiring the Data

One chronic sediment toxicity test for a freshwater invertebrate has been submitted for pendimethalin; however, this is not sufficient to satisfy the Agency’s updated data requirements for outdoor uses in 40 CFR Part 158 (October 26, 2007). For pendimetha lin , available information indicates that b enthic organisms may be exposed
via run

- off or spray drift applications used in agricultural, forest, and residential settings

. Based on calculations in the most recent EFED assessment, the 21

- day sediment

porewa ter EECs predicted for pendiemthalin ranged from 0.4 to 8.00 μg a.i./L ( DP Barcodes 39116 and 394467). The upper end of this range exceeds 0.1 of the most
sensitive acute LC/EC 50 ( 210 μg a.i./L for eastern oyster ), which satisfies one of the
criteria for r equiring chronic whole sediment toxicity testing under 40 CFR Part 158. Furthermore, chronic reproductive effects were seen in water column studies with aquatic invertebrates ( daphnid ), with a NOAEC = 14.5 μg a.i./L and LOAEC = 17.2 μg a.i./L.

Pendimethal in is expected to persist in sediments, based on half

- lives in submitted soil metabolism and aquatic metabolism studies (aerobic soil, 172 days; aerobic aquatic metabolism, 27 days) (MRIDs 4018501 and 47385201 ). These half

- life values exceed the
40 CFR Par t 158 criterion of 10 days.

The third set of trigger criteria for needing chronic testing (K d > 50 or log K OW >3 or K OC > 1000) is also met for pendimethalin (log K OW is 5.18 , and the mean K OC value is

~ 17,000)

. The physicochemical property triggers (K d , K OW and K OC ) reflect the propensity of the chemical to partition onto the particulate or organic matter phases of sediments. Exceeding any one of the physicochemical property triggers listed above is sufficient for indicating the pesticide has reasonable potential for partitioning to the sediment compartment.

A registrant submitted study is available for a chronic whole sediment test on
Chironomus riparius

, therefore, chronic whole sediment tests on Hyalella azteca and Leptocheirus plumulosus are reques ted. Although both are freshwater species, Hyalella
and Chironomus differ subs tantially in their morphology ( crustacean vs. insect), ecological niche (epibenthic v. infaunal species), and physiology. Evidence also suggests
that Hyalella is among the more s ensitive invertebrates based on water column tests (Maund et al., 2002; Weston and Jackson, 2009). Pendimethalin the potential to enter estuarine/marine water bodies based on current usage patterns that include coastal areas. Therefore, testing is also n eeded for an estuarine/marine sediment

- dwelling invertebrate species.

Until the final OCSPP guidelines for chronic sediment toxicity tests are published, the registrant should submit a protocol to EFED for approval prior to test initiation, considering t he following methods:

• Test Method 100.4: Hyalella azteca 42

- d Test for Measuring the Effects of Sediment Associated Contaminants on Survival, Growth, and Reproduction in USEPA 2000 Methods for Measuring the Toxicity and Bioaccumulation of
Sediment

- associa ted Contaminants with Freshwater Invertebrates EPA 600/R

-62 99/064 ( OCSPP 850.1770, in prep. );

• Test Method 100.5: Life

- cycle Test for Measuring the Effects of Sediment

associated Contaminants on Chironomus dilutus (formerly known as C. tentans )
in USEPA 2000 Methods for Measuring the Toxicity and Bioaccumulation of
Sediment

- associated Contaminants with Freshwater Invertebrates EPA 600/R

99/064 ( OCSPP 850.1760, in prep. ); and

• Leptocheirus plumulosus in USEPA 2001 Method for Assessing the Chronic Toxicity of Ma rine and Estuarine Sediment

- associated Contaminants with the Amphipod Leptocheirus plumulosus EPA 600/R

- 01/020 ( OCSPP 850.1780, in

prep. ).

As an alternative to recommending the conduct of 2 chronic (life cycle) sediment toxicity tests, EFED would also con sider a tiered testing approach for sediment toxicity testing. In this approach, sediment toxicity testing would first be conducted with the aforementioned species using the 10

- d (subchronic) sediment toxicity test guidelines (OSCPP 850.1735 and 850.1740) . Then, pending a comparison of estimated environmental concentrations (EEC) in sediment and porewater with toxicity results from
the 10

- d sediment toxicity studies, the need for one or more chronic sediment toxicity
studies would be determined. This tie red testing approach has the potential advantage of reducing the number of chronic (life cycle) studies that would be needed when results of
the 10

- d (subchronic) tests in conjunction with sediment EECs indicate chronic testing is not likely to alter risk assessment conclusions. In some cases, however, this tiered testing approach may result in the conduct of both a 10

- d (subchronic) and a chronic (life cycle) study.

Practical Utility of the Data

How will the data be used? Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms associated with uses of pendimethalin . The data will reduce uncertainties associated with the current risk assessment for benthic species and will improve ou r understanding of the potential effects of pendimethalin

.

How could the data impact the Agency’s future decision

- making? Although there was uncertainty in estimating the effect of pendimethalin on benthic organisms in previous assessments, there was a p otential risk associated with adverse effects identified for other aquatic organisms. Acceptable data for benthic organisms will reduce the uncertainty from the previous assessment If the data indicates that registered pendimethalin usage may pose a ris k of adverse effects to non

- target benthic organisms above the Agency Level of Concern, the Agency may explore decision options to mitigate this risk. T he lack of these data will limit the flexibility the Agency and registrants have in coming into complia nce with the Endangered Species Act, and could result in use restrictions which may otherwise be avoided, or which are unnecessarily

severe.63 Appendix B. Reported Pendimethalin Ecological Incident Summaries in the
EIIS Database

Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

I007677

- 001 Bass, bluegill Possible Registered

u se A tank mix of pesticide was applied to a 4

- acre corn field
next to a 2

- 3 acre pond with a depth of 4

- 6 feet. The distance
from the treatment site was a grass bottom of 14

- 70 feet between the pond and the
treated field. Water and fish samples were taken but findings
were not submitted. The soil had a high moisture level and
an inch of rain fe ll causing drainage into the farm pond. (Site location: Chippewa, OH).

I002685

- 005 Minnow Possible Unknown According to the report, 996 (?)
minnows died in Schwerin
Creek. Their deaths were
attributed to the weed killer
Prowl.

I005880

- 019 Raspberry, unknown

tree Probable Accidental
Misuse This is one of the incidents regarding clomazone that was reported by the Wisconsin Dept. of Agriculture, Trade, and
Consumer Protection in 1997. In Waupaca County trees and raspberries were discolored on
two sides following an application of Command 3ME, Pursuit, and Prowl 3.3 EC at a
distance of less than 300 feet. Also an illegal tank mix was
used.

I000689

- 001 Corn Highly Probable Registered

u se A soybean crop was planted in 1991 and pesticide was applied according to the label. A corn crop was planted in the
same area in 1992 with impunity because the label
stated that there was no "carryover" of pesticide from soybean crop to corn crop..."9
and one

- half months after application", BUT the corn crop
failed. The farmers sued the64 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

pesticide Company for mislabelling the product.

Judgment in June, 1993 was in favor of the plaintiffs and against "Cyanamid",the defendant Company, which had to pay court costs and interest
on decreed amounts.

I014702

- 053 Soyb ean Possible Registered

u se To comply with 6(a)2 requirements, Dow reported an incident in Auburn, IL, in which Pendimax damaged 1100 acres because of a carryover problem.

B000621

- 001 Grass, unknown fruit tree, vegetable Possible Registered

u se Included in the report from the IL Dept. of Agriculture to Region 5 was an incident that took place in Woodstock, IL. A farmer there applied Command (1 1/3 pts/acre) and Prowl (amt. not stated) to a field of beans that was adjacent to the properties of three homeo wners. Some of their plants that were not affected by the spraying were tomatoes, strawberries, and evergreens. But the grass, other vegetables, and fruit trees ended up with bleached and
whitened leaves

I010927

- 005 Corn Possible Registered

u se To compl y with 6(a)2 regulations, Dow reported a complaint from Montfort, WI,
that Pendimethalin 3.3LBS DAS damaged an entire 422 acre crop of corn. Dow's explanation was that "Field
observations of treated areas versus incidental check strips
included stand loss es of up to 65%, leaf burn, and stunted plants. It is strongly suspected that cyanazine and cool, wet conditions following application greatly contributed65 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

to the observed symptoms."

I012366

- 015 Corn field Possible Unknown To comply with 6(a)2 requirements, Dow reported a complaint from Alumbank, PA, that PYTHON damaged 93
acres of corn. Here is the Problem Description according to the Dow report: "Yield lag in PYTHON field split with
PROWL within the same variety. PYTHON corn stunted early i n season."

I013636

- 051 Corn field Probable Registered

use The farmer alleges that crop injury followed hornet herbicide application. Field
observations included uneven corn plants, chlorotic new tissue growth in the whorl, and lack of secondary root hair development. Corn in an unintentional check strip was 6" taller, uniform in height and much darker green in color. Settlement $1,251.63

I014702

- 049 Corn field Possible Registered

use To comply with 6(a)2 requirements, Dow reported an
incident that Keystone with Prowl as a tank mix damaged
corn. Corn exhibited severe burning and some plants died.

I 000663

- 001 Corn, soybean Probable Unknown Alleged crop damage resulted from crop rotation over several years of corn and soybeans accompanied by pesticide application. The rotational crop pesticide application was as
follows:
1989

- Trifluralin, as Treflan*

, and imazethapyr, as Pursuit* applied; soybeans were planted.
1990

- Corn planted.
1991

- Treflan* and Pursuit* applied (soil incorporated); soy beans planted.
1992

- Metolachlor, as Dual*, and dicamba salt, as Banvel*66 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

applied; corn planted.
1993

- Planted corn was observed to be stunted; it tu rned brown and perished. During these years several other herbicides were also applied to this crop area. There was pendimethalin, as Prowl*, and trifluralin, as Tri

- 4*. This rotational crop injury was deemed to be carryover effect and was quite marked b y 1991.
On 0 7/01/92 Inspector Paul Kassel, Iowa State Cooperative Extension Service, made his report, including planting
schedule above. He observed typical Pursuit* carryover symptoms. Residue analysis
revealed a sufficient amount in
the soil to cause the observed damage. He also observed some typical dinitroanaline (DNA), (Treflan* is a DNA), carryover symptoms and felt that it probably contributed to the observed stunting damage. According to the report there is
no record of a similar

occu rrence but the product labels caution regarding the
use of both Prowl* and Pursuit* with corn and soybean
rotation. This event was updated with
I000688

- 001. Soil analysis, 09/01/93, revealed a sufficient amount of pendimethalin, as Prowl*, pro bably another
carryover, to cause crop damage. The residue amount was not given.

I015748

- 018 Cotton Probable Registered

use To comply with 6(a)2 requirements, Dow reported an incident in Somerville, TN, in
which Pendimax + 3.3 EC67 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

Herbicide damaged a field (acreage not stated) of cotton. The report from the Dow inspector was as follows: "Grower applied Pendimax behind a cotton planter while planting cotton. Cotton came up to 2

- leaf stage and received a heavy rain causing dirt which
contained Pendima x to be splashed onto the leaf surface causing damage to the cotton.
Grower followed all label directions and amounts used per
acre within the label."

I013884

- 037 Unknown tree Probable Unknown This is from the 1999 Annual Report from the Washington State Department of Health Pesticide Incident Reporting and Tracking Review Panel, November 2000, from the 1998 PIRT Data. A driveway was
treated with a herbicide and a 100 year old black walnut, plu s several other plants showed symptoms of herbicide application. Analysis of foliage was found positive for Pendimethain. No analysis results was given.

I004869

- 001 Azelea Probable Registered

use A greenhouse floor in Sylmar was treated with the pestici de Pendulum, causing tinting and wilting of azaleas in the greenhouse. The damage progressed, making 172,637 azaleas unmarketable. Property
loss was claimed to be $600,000.

I009262

- 054 Grass Probable Registered

use As part of its reporting of August, 1999, incidents, Scotts Co. included a complaint from a homeowner in Edison, N.J.. She had used one 15M bag of
Turf Builder with Halts and one bag of Turf Builder with Weed68 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

Control; the first application was in the spring and the second in the fall, and b oth times the lawn was completely
burned out. The customer was to be given a refund.

I013587

- 052 Corn Probable Unknown In the 2000

- 2001 Annual Report of the Pesticide Incident Reporting and Tracking (PIRT) Review Panel of Washington
State there is an incident that took place in Benton County, July 23, 1999. The herbicide
mentioned is Pendimethalin. It was, evidently, the cause of an
earlier event related to a herbicide application made in 1998. Large limbs in trees were dying, and there was damage t o ornamentals. This is a notice of
correction to CASE# 40Y

- 98

I010837

- 069 Grass Possible Unknown To comply with 6(a)2 regulations Novartis reported a complaint from Caledonia, NY, that BICEP LITE II Magnum damaged all of a corn crop. There is a discrepan cy in the Novartis report; on the front page, the Treated Acres is said to be 130, but the "Plant A" Crop Damage report shows that
65 acres were treated and 65
acres were affected. In each case, the report says that 100% of the crop was affected.
PROWL w as said to be
involved also but no details were given of its involvement. Here is the report of the Novartis inspector: "Corn showed severe stunting and twisting but thought it would grow out of these symptoms. It appeared that grower was
satisfied unti l harvest of silage. A $4,000 settlement is required69 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

now before more yield is
determined."

I012094

- 001 Unknown tree Possible Registered

use To comply with 6(a)2 requirements, Scotts Co. reported a complaint from a golf course in Fort Worth, TX, that Ronstar had damaged 30 acres of Tifsport Bermuda fairways. Here is Scotts Co.'s report: "30 Acres of Tifsport Bermuda fairways, Ronstar

Burn. M ade first observation on Saturday 8/25 after being alerted to damage by DSR. Tifsport fairways had severe turf burn in the overlap areas. The common Bermuda rough areas were undamaged. The decision was made by Duane and myself to let the turf

recover an d take another look on Wednesday, 8/29. Damage
still severe in some areas. Turf is alive, just recovering slowly." Evidently there was no damage settlement made on the
claim.

I011838

- 106 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Wakefield, VA, that VALOR damaged two sites of peanuts, one of 6 acres and
the other 36. PROWL and DUAL were also applied at 0.5 pt/acre. The damage symptoms
were described as: "Phytotoxicity: Heavy damage to leaves & pe tioles."

I011838

- 085 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Carnegie, OK, that VALOR damaged two sites of peanuts, one of 48 acres and one of 58. Other products used
were PROWL and TEMIK but
no detail s were given of their70 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

application rates. The symptom
was described as "Phytotoxicity: Brown, dead peanuts."

I011838

- 011 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Pelham, GA, that VALOR damaged 10 acres
of a 224

- acre crop of peanuts. The symptoms were "desication of stems, petioles, leaves."
PROWL was in the tank mix but no details were gievn about
its concentration.

I011838

- 074 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Fort Cobb, OK, that VALOR damaged two sites of peanuts, one of 110 acres and one of 90. Also applied was PROWL at 2.4 pints/acre. The symptom of damage was noted as "Phytotoxicity: Slow growing, severe stunting."

I011838

- 060 Peanut Po ssible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Hydro, OK, that VALOR damaged 58 acres of peanuts. PROWL and
ORTHENE IFS were also
involved but no details of their use were given. The symptoms
were described as "Leaves unfolded & matted to ground,
terminals burnt out."

I011838

- 062 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Lookeba, OK, that VALOR damaged 160 acres of peanuts. PROWL PPI was another product applied but

no details were given of its use. The symptoms were described as "Dry leaves @ cracking." (sic)

I011838

- Peanut Possible Unknown To comply with 6(a)271 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

061 requirements, Valent reported a complaint from Hydro, OK, that VALOR damaged two peanut sites, one of 124 acres
and the other 93. PROWL and TEMIK were also applied but no details were given of their use. The symptoms were
described as "Burnt terminals & foliage brown."

I011838

- 065 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Hydro, OK, that VALOR damaged two sites of peanut crops, one of 109
acres and one of 98. PROWL
was also used at the time of application but no details were given. The symptoms of the damaged crop were "Burnt plants, not growing. "

I01183 8

- 064 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Hydro, OK, that VALOR damaged two sites of peanut crops, one of 190
acres and the other 120. Other products used at the time of application were PRO WL, DUAL, and SPREADER but no details were given of their use. The symptoms of the affected plants were described as "Burnt plants, not growing."

I011838

- 088 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Ft. Cobb, OK, that VALOR damaged two peanut sites, one of 99 acres
and one of 28. PROWL and THIMET were also applied but their application rates were not given. The symptom of damage was given as "Phytotoxicity: Burnt tops, stunting."

I011838

- Peanut Possible Unknown To comply with 6(a)272 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

079 requirements, Valent reported a complaint from Fort Cobb, OK, that VALOR damaged two sites of peanuts, one of 32 acres and
the other 28. PROWL was also applied at 2.5 pts/acre. The damage symptom was
described as "P hytotoxicity: Burned leaves, stunted."

I011838

- 056 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Windsor, NC, that VALOR damaged 80 acres of peanuts. Other products used at application were OUTLOOK, PURSUIT, VAPAM, and
PROWL but no details were given. The symptoms listed were "Burnt leafes, petioles" (sic).

I011838

- 069 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Gracemont, OK, that VALOR damaged two sites of pe anuts, one of243
acres and the other 126. PROWL was also applied at 2.4 pints/acre. The symptoms of the plants were described simply as "Phyotoxicity."

I011838

- 058 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Fort Cobb, OK, that VALOR damaged to sites of peanuts, one of 37 acres and
one of 34. PROWL and
SUPER BIO were also involved but no details werer given of their use. The symptoms were described as "Burnt leaves, stunting, slow growing."

I011838

- 089 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Sayre, OK, that VALOR damaged all 122 acres of one peanut site, and 40 acres73 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

of another 210 acre plot. PROWL was also applied but
no details of its use were given. The symptom was described as "Phytotoxicity: Burnt leaves, plants look dead."

I011838

- 098 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Milburn, OK, that VALOR damaged 255 acres of peanuts at one site and
40 acres at another. PROWL was also applied but no details of its use were given. The damage symptom was reported as: "Phytotoxicity: Burnt spots,
reduced stand."

I011838

- 090 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent report ed a complaint from Erick, OK, that VALOR damaged 100 acres of
a 125

- acre peanut crop. PROWL was also applied but no details of its use were given. The damage symptom was described as "Phytotoxicity:
Burnt leaves."

I011838

- 091 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Holdenville, OK, that VALOR damaged two sites of peanuts, one of 60 acres and one of 20. Other products applied were PROWL and
CYCLONE but no details of their use were given. The
symptoms of damage were described as: "Phytotoxicity: Burnt peanuts, dead plants."

I011838

- 109 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Windsor, VA, that VALOR damaged 55 acres of peanuts. Also applied were
DUAL at 1.3 pt and PROWL at 1.5 pt/acre. The damage74 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

symptoms were described as: "Phytotoxicity: Slow emerge w/burned leaves & petioles."

I011838

- 071 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Lookeba, OK, that VALOR damaged 52 acres of peanuts. PROWL was also applied, at 1 quart/acre. The symptoms of damage were "Phytotoxicity: Initial leaves
burned."

I011838

- 111 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Girade, GA, that VALOR damaged 26 acres of peanuts. PROWL, BRAVO,
and STRONGARM were also applied but the application rates were not given. The damage symptoms were reported as: "Phytotoxicity: Burnt lower
leaves."

I011942

- 002 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Girade, GA, that VALOR damaged an entire peanut crop. There were two sites, one of 26 acres and another of an unspecified area. Other products used at the time of application were Prowl, Bravo, and Strongarm.

I011838

- 107 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Yale, VA, that VALOR damaged 23 acres of peanuts at one site, and 3 acres
at another. PROWL was also applied at 1.4 pt/acre. The damage symptoms were reported as: "Phytotoxicity:
Burned and stunted."

I011838

- 014 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Camilla, GA,75 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

that VALOR damaged all 48 acres of a peanut crop.
PROWL and THIMET were also applied but no information was given regarding their application rates. The symptoms of the damage were "stunting, reduction."

I011838

- 035 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Tifton, GA, that VALOR damaged 209.8 acres of peanuts. Othe r products used at the time of application were
PROWL and ROUNDUP but no details were given of their application rates.

I011838

- 073 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Carnegie, OK,
that VALOR damaged 45 acres of peanuts. PROWL was also applied but no details were given of its use. The symptom of the damage was described as "Phytotoxicity: Burn on low
leaves."

I011838

- 039 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Lenox, GA, that VALOR damaged 91.5 acres of peanuts. PROWL was also applied but no details of its use were given. The symptoms
shown were "Burnt & stunted plants."

I011838

- 047 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Tifton, GA, that VALOR damaged two peanut crops, one of 14 acres and the
other 26.2 acres. Also involved
were PROWL and DUAL although no details were given about them. The symptoms
noted were "Burnt & wilted76 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

plants."

I011838

- 041 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Douglas, GA, that VALOR damaged 260 acres of peanuts. there were 60
acres at one site and 200 at
another. PROWL was also
involved but no de tails were given of its use. the symptoms
noted were "Burnt & wilted plants."

I011838

- 043 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Douglas, GA, that VALOR damaged all 25 acres of a peanut crop.
PROWL was also involved but no details were given of its use. The description fo the symptoms was "Not developing, root strong."

I011838

- 050 Peanut Possible Unknown To comply with 6(a)2 requirements, Valent reported a complaint from Wray, GA, that
VALOR damaged 29.7 acres of a peanut crop. PROWL was
also involved but no details of its use were given. The symptoms cited were "Burnt & wilted plants."

I015278

- 001 Potato Probable Registered

use This 6(a)(2) reported by Griffin
LLC is one of the most complete incident I have seen. Gives history of the field from April 1990 to June 2003 when the symptoms appeared. There were several applications of many different herbicides during this period. The first applications were on April 2, 1990 to an asparag us crop. In 2000, there was another application to asparagus. The
field was left fallow for 2001 and 2002 with out any77 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

herbicides being applied. The field was prepared for potatoes in the spring of 2003 and several more applications of herbicides, April 1 , April 25 and May 10. The report from the fieldsman was that the crop emerged normally, but began to
show chlorosis before row closure. On June 20, 2003 it became evident that the plants were dying. The fieldsman took composite soil samples for analysis of diuron, linuron, terbacil and simazine. Only
diuron was detected at 0.1 ppm. Additional testing show detections of pendimethalin, trifluralin, chlorpyrifos diuron, and DCPMU (primary metabolite of diuron). See report for full history.

I010927

- 004 S oybean Probable Registered

use To comply with 6(a)2 requirements, Dow reported a complaint from Greenville, MS,
that Pendimethalin 3.3LB DAS damaged all 809 acres of a soybean crop. According to Dow's account of the incident,
the effect known as Brittle S tem occurs when Pendimax is surface applied at planting, followed by heavy rainfall. As the soybeans emerge the Pendimax forms a "toxic layer" around the stem of the plant at ground level. This make it very
brittle and causes it to fall over.

I010927

- 00 6 Soybean Possible Registered

use To comply with 6(a)2 regulations, Dow reported a complaint from Litchfield, MI,
that Pendimethalin 3.3LBS DAS damaged 150 acres of soybeans (out of a total of 180 acres). This pesticide was tank mixed with Python and78 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

FirstRate. Following is the

account o f the Dow inspector: "Two days after planting, excessive (5") of rainfall occurred. Within 7 days I walked these fields showing stunting and a swollen, brittle, and callused hypocotyl. My references indicated a higher than normal probability of DNA inju ry. We made the decision to replant into the remaining 55

- 60% stands. The
fields were monitored all summer and taken to yield. I was present for harvest, all trucks were weighed and comparison made to other conventional soys planted on
similar dates in nearby fields."
I called Dow to ask whether any data was available on the yield for this crop as well as others in the area, but they had
no such data. To comply with 6(a)2 regulations, Dow reported a complaint from Schoolcraft, MI, that Pendimethalin 3.3 LB DAS damaged 78 acres of soybeans. This pesticide was tank mixed with Python. The account of the Dow inspector is
as follows: "Callus area forme d at soil level on many of the plants. In a wind storm in August many plants were
knocked down. Plants could be easily snapped off just by walking through them."

I010927

- 008 Soybean Possible Registered

use To comply with 6(a)2 regulations, Dow reported a complaint from Vicksburg, MI, that a tank mix of Python, Pendimax, and FirstRate damaged 65.8 acres of79 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

soybeans. The account of the Dow inspector is as follows: "Pendimax, Python, FirstRate tank mix. Beans emerged,
receive a lot of rain and died
back to the ground. Especially prevalent where spray boom overlapped. late in the season, beans were very brittle." To comply with 6(a)2 regulations, Dow reported a complaint from Cedar, KS, that Python damaged all 180 acres of a soybean crop. The Dow inspec tor's report is as follows:
"Grower used too much active of Python on a high pH soil over 7.9. The grower was emulating the Broadstrik +
Dual and the ratios were off contributing to high AE per
acre."

I010927

- 007 Soybean Possible Registered

use To comply with 6(a)2 regulations, Dow reported a complaint from Schoolcraft, MI, that Pendimethalin 3.3 LB DAS damaged 78 acres of soybeans. This pesticide was tank mixed with Python. The account of the Dow inspector is
as follows: "Callus area formed

at so il level on many of the plants. In a wind storm in August many plants were
knocked down. Plants could be easily snapped off just by walking through them."

To comply with 6(a)2 regulations, Dow reported a complaint from Vicksburg, MI, that a tank mix of Python, Pendimax, and FirstRate damaged 65.8 acres of soybeans. The account of the Dow inspector is as follows:80 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

"Pendimax, Python, FirstRate
tank mi x. Beans emerged,
receive a lot of rain and died back to the ground. Especially prevalent where spray boom overlapped. late in the season, beans were very brittle."

To comply with 6(a)2 regulations, Dow reported a complaint from Cedar, KS, that Pyt hon damaged all 180 acres of a soybean crop. The Dow inspector's report is as follows:
"Grower used too much active of Python on a high pH soil over 7.9. The grower was emulating the Broadstrik +
Dual and the ratios were off contributing to high AE per
acre."

I014702

- 057 Soybean Possible Registered

use To comply with 6(a)2 requirements, Dow reported an incident in Fonda, IA, in which Pendimax and/or Authority, with wet conditions, damaged 251 acres of soybeans. Soybean stems became brittle
and broke off at ground level. Settlement for 1.36 bushels per acre at $7.76/bu, for a total of $2562.74.

I014702

- 056 Soybean Possible Registered

use To comply with 6(a)2 requirements, Dow reported an
incident that Pendimax and/or Authority, along with extreme

wet conditions, caused brittle stems allowing the plant to break off at the ground. Settlement was at $7.76/bushel for 1 bushel per acre, for a total of $2187.16. This occurred in Fonda, IA.

I014702

- 058 Soybean Possible Registered

use To comply with 6(a)2 requirements, Dow reported an incident in Ayrshire, IA, in81 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

which extreme wet weather allowed the herbicides, Pendimax and Python, to stay
in continuous contact with the soybeans in a 543 acre crop.
This caused stem brittleness at the ground level and the n the plants broke off causing a stand and yield reduction. Settled on 4.5 bushels per acre at $7.66/bu, for a total of $18,717.21.

I014702

- 055 Soybean Possible Registered

use To comply with 6(a)2 requirements, Dow reported an incident in Ruthven, IA, in which 56 acres of soybeans were damaged by Python and
Pendimax 3.3. Wet weather contributed to the problem, causing brittle stems and the death of some plants. A total settlement of $1693.44 was

made.

I014702

- 059 Soybean Possible Registered

use To comply with 6(a)2 requirements, Dow reported an
incident that Pendimax and Python, along with extreme wet weather, caused damage to soybeans. Prolonged contact of the herbicides with the soybean stem caused callusing and
brittleness.

I014702

- 061 Soybean Possible Registered

use To comply with 6(a)2 requirements, Dow reported an
incident in which Pendimax and/or Python, along with extreme wet weather, caused soybean brittle stems and the death of some plants. A total settlement of $1639.44 was made, based on the reduction in yield.

I015748

- 046 Soybean Possible Registered

use To comply with 6(a)2 requirements, Dow reported an incident in Ashton, IA, in which
Pendimax 3.3 EC Herbicide damaged an entire 460

- acre82 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

crop of soybeans. The Dow inspector's report said: "Pendimax applied in mid

April. 3 weeks later, disked in. Soybea ns were showing injury/disease more noticeably in overlap areas, but all across
field. Problems attributed to planting depth, Pendicamx slowing soybean growth allowing seed to sit in cold, we ground longer. Settled for cost of Pendimax To comply with 6(a)2 requirements, Dow reported an incident in Elm Creek, NE, in which Starane Herbicide damaged 46 acres of
field corn. The Dow inspectpor's report said: "The corn field being settled on was a Mycogen conventional hybrid (2R773) which is sensitive to PGRs. The evening following chemical application, the wind picked up to 60 mph gusts which snapped off an estimated
60% of the corn. The corn which was still standing showed very clear signs of PGR damage (pictures available). It
was then decided to wai t until harvest to see how much yield loss would occur. By using county data I calculated that the 2004 yields were on average down 6% in the given area. Therefore, 6% was removed
from the field's historical average (derived from the grower's insurance c ompany) in
order to create a more accurate estimation of yield loss for this growing season."

I016962

- 001 Soybean Possible Registered

use Grower applied 3.3 of
Pendimax with 3

- inch soil incorporation. The soybean83 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

hypocotlys were swollen and
brittle causing stand loss throughout the season and yield
loss at harvest.

I015 175

- 001 Soybean Possible Registered

use To comply with 6(a)2 requirements, DuPont reported a complaint from a soybean farmer in Arkansas, alleging that DuPont's Authority Herbicide, and Prowl, damaged his 5,000 acre crop. In the next week, DuPont representatives visited many sites having similar symptoms. In the case of the Arkansas man, the products were sprayed at planting with 2 different sprayers. The beans emerged prior to rec eiving the first rain,
after which rainfall had been
rather consistent and with occasional great intensity. Soon after the first rain, the beans started showing symptoms that appear to be
consistent with those associated
with sulfentrazone. There were

va riations in the soil in these fields, and the greater damage
seemed to be related to the lighter soil; the affected plants have a yellowish look. DuPont's report admitted that the symptoms may be
consistent with those of
sulfentrazone.

I0105 81

- 083 Grass Probable Accidental
Misuse To comply with 6(a)2 requirements, Scotts reported a complaint from Chicago, IL,
that Turf Builder with Halts damaged about 75% of a lawn. The approximate area of the lawn was 1200 sq ft and the customer applied about half of a 15M bag (which would be an excessive amount). Scotts was84 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

to offer a refund.

I010581

- 092 Grass Probable Registered

use To comply with 6(a)2 requirements, Scotts reported a complaint from Woodbury, NJ,
that Turf Builder with Halts damaged a lawn. The cust omer used the product which he claims to have been lumpy and which evidently did not spread evenly. There are brown patches throughout the lawn
and it is estimated that 50% of the lawn was damaged. Scotts offered to provide a refund for
the seed and fert ilizer.

I010581

- 082 Grass Probable Accidental
Misuse To comply with 6(a)2 requirements, Scotts reported a complaint from New Albany, IN, that Crabgrass Preventer Plus Lawn Fertilizer damaged 90% of a lawn. Three days after the complainant applied
the product the grass was dead but the crabgrass was thriving. The Scotts inspector explained that applying the product at this time on existing crabgrass
would not work. The complainant used a rotary spreader that had only one setting. The temperature was 65 degrees and the product was
watered in.

I007495

- 001 American robin, rock
dove Possible Unknown The State of Kansas Deot. of
Wildlife and Parks received a report of a bird kill in Hutchinson in April, 1998. Six
American robins and 6 or 7
rock doves wer e found dead after the application of pendimethalin. The biologist who investigated the incident thought that pendimethalin was responsible for the event but there was no report of a toxicological analysis to85 Table B

- 1. Pendimethalin Incident Report Summaries

Incident # Organism(s)
Affected Certainty of
Involvement Legality of
Use Description

confirm this possibility.