### 1 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

August 5, 2015

PC Code: 038901, 038904, 038905 DP Barcode: 426244

MEMORANDUM

SUBJECT: EFED Registration Review Problem Formulation for Endothall

FROM: Christina Wendel, Biologist James Lin, Environmental Engineer Environmental Risk Branch 2 Environmental Fate and Effects Division (7507P)

And

Laura Parsons, Associate Branch Chief Risk Assessment & Science Support Branch (RASSB) Antimicrobials Division (7510P)

REVIEWED BY: R. David Jones, Ph.D., Senior Agronomist Elyssa Arnold, Risk Assessment Process Leader (RAPL) Brian Anderson, Branch Chief Environmental Risk Branch 2 Environmental Fate and Effects Division (7507P)

TO: Garland Waleko, Chemical Review Manager Tom Myers, Team Leader Kevin Costello, Branch Chief Risk Management and Implementation Branch 2 Pesticide Re-evaluation Division (7508P) 2015.08.06 08:15:59 -04'00'

2015.08.06 08:25:25 -04'00'

2015.08.06 09:55:34 -04'00' 2015.08.06 15:08:48 -04'00'



## ROBERT JONES Digitally signed by ROBERT JONES DN: c=US, o=U.S. Government, ou=USEPA, ou=Staff, cn=ROBERT JONES, dnQualifier=0000006506 Date: 2015.08.10 11:00:40 -04'00' 'PS



# STEVEN WEISS Digitally signed by STEVEN WEISS DN: c=US, o=U.S. Government, ou=USEPA, ou=Staff, cn=STEVEN WEISS, dnQualifier=0000013584 Date: 2015.08.11 12:52:49 -04'00' For

### 2 

## 

1. Executive summary ............................................................................................................. .... 3 2. Introduction .................................................................................................................. ........... 5

a. Mode of Action ................................................................................................................ .... 5 3. Use Characterization .......................................................................................................... ..... 6 4. Conclusions from Previous Risk Assessments ....................................................................... 7

a. Ecological Risk Assessment ................................................................................................ 7 b. Drinking Water Exposure Assessments ............................................................................... 9

c. Clean Water Act Programs .................................................................................................. 9 5. Environmental Fate and Transport.......................................................................................... 9 6. Receptors...................................................................................................................... ......... 13

a. Effects to Aquatic Organisms ............................................................................................ 15 b. Effects to Terrestrial Organisms ........................................................................................ 17

c. Ecological Incidents .......................................................................................................... . 19 7. Exposure Pathways of Concern ............................................................................................ 21 8. Analysis Plan ................................................................................................................. ....... 23

a. Stressors of Concern .......................................................................................................... 23 b. Measures of Exposure ........................................................................................................ 2 3

c. Measures of Effect ............................................................................................................ . 24 d. Endangered Species Assessments ...................................................................................... 24

e. Endocrine Disruptor Screening Program ........................................................................... 25 9. Preliminary Identification of Data Gaps ............................................................................... 25

a. Environmental Fate ............................................................................................................ 25 b. Effects ....................................................................................................................... ......... 26 10. References .................................................................................................................... ...... 47

a. Submitted Environmental Fate Studies .............................................................................. 48 b. Submitted Ecological Toxicity Studies .............................................................................. 52 APPENDIX A. SLUA Summary Table for Endothall.................................................................. 84 APPENDIX B. Endothall Incidents .............................................................................................. 85 APPENDIX C. SIP & STIR Inputs and Outputs for Endothall Acid, and the dipotassium and mono (N,N-dimethylalkylamine) salts of endothall ..................................................................... 89

### 3 

## 1. Executive summary

The Environmental Fate and Effects Division (EFED) has completed the problem formulation for the ecological risk, environmental fate, endangered species, and drinking water assessments to be conducted as part of the registration review of endothall (PC code 038901). Endothall acid is the herbicidal active ingredient in all of the endothall-containing herbicide formulations but only salts of endothall are sold as pesticide products. For consistency, concentrations and endpoints are all presented in terms of endothall acid equivalents. The endothall formulations for this riskassessment consist of either a dipotassium salt (PC code 038904) or a mono N,Ndimethylalkylamine salt (PC code 038905). The problem formulation describes the methods planned to be used during the completion of drinking water and ecological risk assessments in support of registration review and provides an overview of the environmental fate, ecological effects, potential risks associated with the use, and uncertainties unique to the risk assessment of endothall. This document also identifies additional studies that would be beneficial to the conduct of an ecological risk assessment.

Endothall is applied directly to water to control aquatic vegetation and to terrestrial, agricultural sites for weed control. The mono N,N-dimethylalkylamine salt can also be applied directly to water in cooling towers to control freshwater and saltwater molluscs. Risk assessments conducted to date have identified potential risks to aquatic and terrestrial plants and animals, although risks vary somewhat across the different salts and use patterns. The mono N,N-dimethylalkylamine salt has been shown to be substantially more toxic than the dipotassium salt for all aquatic species tested, likely due to toxicity of the cation in addition to that of the endothall acid following dissociation of the salt. Therefore, toxicity data on both salts and the free acid are recommended for the aquatic risk assessment. However, a full suite of dimethylalkylamine salt, and a full suite of either the acid or the dipotassium salt is sufficient (including chronic toxicity), as the toxicity of the acid and the dipotassium salt is similar, and the endpoints can be bridged on an acid equivalent basis. Additional data are needed primarily for either the acid and/or dipotassium salt to have a complete data set for aquatic toxicity. In addition, there are two previously submitted freshwater and estuarine/marine invertebrate chronic toxicity studies, for the free acid and the dimethylalkylamine salt, respectively, that do not provide reliable endpoints for use in risk assessment, and, therefore, new toxicity data are needed.

For terrestrial species, like the aquatic species, a full suite of dimethylalkylamine salt, and a full suite of either the acid or the dipotassium salt are recommended for risk assessment. Therefore, toxicity data needed include acute oral passerine toxicity, avian reproduction, and honey bee data (due to the new data requirements).

For both the aquatic and terrestrial assessments, the most sensitive endpoint from the dimethylalkylamine salt or the free acid will be used to assess dimethylalkylamine salt uses. The most sensitive endpoint from the dipotassium salt or the free acid will be used to assess dipotassium salt uses. All endpoints will be expressed in terms of endothall acid equivalents for risk estimation.

### 4 The following are the needed data for endothall:

Data Needs

x Ecotoxicity Data Aquatic

o OCSPP 850.1300: Freshwater invertebrate life cycle (acid and/or dipotassium salt)

o OCSPP 850.1350: Saltwater invertebrate life cycle (acid and/or dipotassium salt and dimethylalkylamine salt)

o OCSPP 850.1400: Saltwater fish early-life stage (acid and/or dipotassium salt)

o or OCSPP 850.1075 Freshwater fish acute toxicity with fathead minnow (acid only) for calculation of an ACR

Terrestrial

o OCSPP 850.2100: Avian acute oral toxicity with passerine species (dimethylalkylamine salt and acid or dipotassium salt)

o OCSPP 850.2300: Avian reproduction; bobwhite quail (acid and/or dipotassium salt) and mallard duck (dimethylalkylamine salt)

o OCSPP 850.3020: Honeybee acute contact toxicity study (both salts)

o OECD TG 213 and Non-guideline special studies: Honey bee adult acute and chronic oral toxicity studies (both salts)

o OECD TG 237 and Non-guideline special studies: Honeybee larval acute and chronic oral toxicity studies (both salts)

o Non-guideline special studies: Field trial measuring residues of endothall in pollen and nectar (both salts)

o Special study OECD TG 75 and OSCPP 850.3040: Semi-field testing for pollinators and Field testing for pollinators (both studies are conditionally required pending the results of the Tier I

– laboratory based studies listed above; if needed protocols for each study must be submitted for review prior to study initiation; both salts would be tested).

x Environmental Fate Data For coco-alkylamine cation, a part of mono (N,N-dimethylalkylamine) salt of endothall, including:

o OCSPP 835.2100: Hydrolysis

o OCSPP 835.2240: Aqueous Photolysis

o OCSPP 835.4100: Aerobic Soil Metabolism

o OCSPP 835.4400: Anaerobic Aquatic Metabolism

o OCSPP 835:4300: Aerobic Aquatic Metabolism

o OCSPP 835.1230: Batch Equilibrium

### 5 For the mono N,N-dimethylalkylamine salt to support the Down the Drain assessment 1 

### :

o OCSPP 850.3300: Activated Sludge Respiration Inhibition

o OCSPP 835.3110: Ready Biodegradation

o OCSPP 835.3220: Porous Pot Study

o OCSPP 835.3240: Simulation Test

– Aerobic Sewage Treatment

o OCSPP 835.3280: Simulation Test

– Assess Biodegradability in Wastewater



## 2. Introduction

Endothall, known by the trade names Aquathol K®, Aquathol Super K®, Hydrothol 191®, Desicate II, and Accelerate®, is a liquid or granular herbicide that has two salt forms, a dipotassium salt, and a mono-(N,N-dimethylalkylamine) salt (referred to as N,N-amine in this assessment). The dipotassium formulations (Aquathol® product line) are used to control submerged aquatic weeds,such as hydrilla and curlyleaf pondweed and for irrigation to non-food crops. The endothall N,Ndimethylalkylamine salt formulations are used in both aquatic (Hydrothol 191) and terrestrial (Accelerate and Desicate product line) applications. Hydrothol 191 is used to control algae and submerged aquatic vegetation in small areas, such as drainage and irrigation canals and small pond or lake areas and for irrigation to non-food crops. Accelerate and Desicate II are used terrestrially as defoliants on cotton, seed production alfalfa and clover.

One N,N amine product, TD 2335 Industrial Biocide-Molluscicide, is used to control freshwater and saltwater mussels in once-through and recirculating cooling tower waters. The product is to control established populations and to prevent settlement/attachment of immature forms of molluscs.



## a. Mode of Action Endothall acid is the herbicidal active ingredient in all of the endothall-containing herbicide formulations. Endothall is formulated as a dipotassium salt or a mono (N,N-dimethylalkylamine) salt. The dissociation constants of both of the endothall salts indicate that at most environmentalpH levels, the endothall salt, endothall acid, and the corresponding cation (potassium or N,Ndimethylalkylamine) will all be present. In addition, there are significant differences in toxicity tocertain organisms between the endothall dipotassium salt and the endothall mono (N,Ndimethylalkylamine) salt. Therefore, this risk assessment examines all of the potential chemical exposures from endothall application separately. For consistency, concentrations are presented in terms of endothall acid equivalents. Terrestrial toxicity data are not available for the potassium cation or coco-alkylamine cation.

1 Only one of the biodegradation studies is required. The results of the ASRI test will determine which of four biodegradation tests is/are required. If the ASRI test EC 50 is less than or equal to 20 mg/L, then either the (i)Biodegradation in Activated Sludge Study or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units or (iii) the Porous Pot Test is expected to be required. If the ASRI test EC 50 is greater than 20 mg/L, then the registrant would likely be required to conduct either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready Biodegradability study is conducted and passes, then no further testing would be expected to be required. If, however, the antimicrobial fails the Ready Biodegradability study, then the a) Biodegradation in Activated Sludge or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units, or c) the Porous Pot study would likely be required.

### 6 Endothall acts mainly as a contact herbicide, although it is somewhat mobile in plant tissues when applied at rates lower than those used for contact kill and can cause plant death through foliage absorption. Endothall interferes with plant respiration by affecting protein and lipid biosynthesis and disrupting plant cell membranes. 

## 3. Use Characterization

Endothall is used for (1) direct application to water to control aquatic plants, (2) as a desiccant on cotton, potatoes, seed production alfalfa and clover, and (3) as a blossom thinner on apples. According to the Screening Level Usage Analysis (SLUA) provided by the Biological and Economic Analysis Division (BEAD), for endothall case (002245) between 2004 and 2012 an average of 3,000 lbs a.i./yr was used on alfalfa, 2,000 lbs a.i./yr was used on cotton, and 4,000 lbs a.i./yr was used on potatoes in the United States (USEPA, 2014). The SLUA reports do not include non-crop uses. Application rates are similar for all three use patterns. The highest maximum application rates are < 2.5 lb a.i./A.

Table 1 lists the maximum use patterns for the labeled use sites for endothall, mono (N,N,- dimethylalkylamine) salt (038905). Table 2 lists the maximum use patterns for the labeled use sites for endothall dipotassium salt (038904). All these uses are based on the Label Use Report Package created by BEAD in support of Registration Review (USEPA, 2014b).

Table 1. Endothall, mono (N,N,-dimethylalkylamine) salt (PC 038905) Label Use Information

Use Single Max Application Rate (lbs a.i./A) Max Application

Rate per Crop Cycle (lbs a.i./A) Max Application

Rate per

Year (lbs a.i./A) Min Application Retreatment Interval

(days) Max # of Applications

Per Year Formulation, Application

Methods

Alfalfa 1.7 NS NS NS NS SC, Broadcast - Aerial, Ground Clover 1.7 NS NS NS NS Potato, White/ Irish

(or Unspecified) 2.3 NS NS NS NS

Aquatic Areas/ Water* 30.9 (lb/a-ft) NS NS 7 NS SC, (* also for Granular),

Ground, Water Treatment, Water Treatment (Surface) Irrigation Systems 30.7 (lb/a-ft) NS NS NS NS

Lakes/ Ponds/ Reservoirs (w /o Human or Wildlife Use) 30.7 (lb/a- ft) NS NS NS NS

Cotton (Unspecified) 0.2859 NS NS NS NS SC, Ground, Aerial, Desiccation NS=not specified; NDC=no dosage conversion; SC= Soluble Concentration/Liquid

### 7 Table 2. Endothall, dipotassium salt (PC 038904) Label Use Information

Use Single Max Application Rate (lbs a.i./A) Max Application Rate per Crop Cycle (lbs a.i./A) Max Application

Rate per

Year (lbs a.i./A) Min Application Retreatment Interval (days) Max # of Applications

Per Year Formulation, Application

Methods

Aquatic Areas/ Water 13.9 (lb/a-ft) NS NS NS NS SC, Ground, Aerial, Water Treatment, Water Treatment (Surface), Dripline Application 5 ppm 7

Lakes/ Ponds/

Reservoirs (w /o Human or Wildlife Use) 30.7 (lb/a-ft) NS NS NS NS 5 ppm 5

Apples 0.28 ( 0.3 lbs ae) NS 0.846 (0.6 lb ae) >24 hrs (cannot be applied more than once in 24

hour period) 2 SC, Ground, Airblast spray

NS=not specified; SC= Soluble Concentration/Liquid



### For the antimicrobial use of N,N-amine to control molluscs in industrial cooling towers, the product can be applied at up to 3 ppm endothall (24 gallons product per 1 million gallons of water) and the concentration should be maintained for up to 140 hours. Applications should be made to an area of uniform mixing within the system. No holding period or deactivation time is required by the label.



## 4. Conclusions from Previous Risk Assessments a. Ecological Risk Assessment
A number of ecological risk assessments have been conducted on endothall. The conclusions from the past assessments are summarized in Figure 1 and Table 3 below. Figure 1. Graphic Summary of Potential Risks of Current Endothall Uses

### 8 Table 3. Evidence of Risk to Taxonomic Groups from Assessed Endothall Uses
Conclusion: No Risks of Concern Certainty: High Conclusion: Risks of Concern Identified Certainty: High Fish : Acute listed and non-listed fish (freshwater and estuarine/marine) and chronic LOC exceedances for freshw ater fish. No estuarine/marine fish chronic toxicity data was previously available. A study was submitted for the mono (N,N, -dimethylalkylamine) salt and the endpoint was converted to a.e. ; therefore it can be used to represent the endothall estuarine/marine fish chronic toxicity endpoint for both salts . The estuarine/marine toxicity fish data are an order of magnitude more sensitive than the freshwater data, indicating there would also be chronic risk to estuarine/marine fish as well. Aquatic Invertebrates : Acute listed and non-listed fish (freshwater and estuarine/marine) LOCs were exceeded. No estuarine/marine aquatic invertebrate (mysid) chronic toxicity data was previously available. A study w as submitted for the mono (N,N,

- dimethylalkylamine) salt and the endpoint was converted to a.e .; therefore it can be used to represent the endothall estuarine/marine aquatic invertebrate (mysid) chronic toxicity endpoint for both salts. The estuarine/marine toxicity fish data are within an order of magnitude of the freshwater invertebrate data, ind icating there would also be chronic risk to estuarine/marine invertebrates as well. Terrestrial & Aquatic Plants : Endothall is an herbicide used to control aquatic and terrestrial vegetation ; risk to non- target listed and non -listed terrestrial monocot and dicot plants based on exposure via runoff and/or spray drift have been identified. Incidents have been reported on terrestrial plants. Birds (surrogates for reptiles and terrestrial-phase amphibians) : Acute dose- and dietary-based LOC exceedances for multiple size classes and feeding guilds of birds; both acute and chronic LOCs have been exceeded. Consuming a variety of dietary items (RQ values ranged 0.1- 42.13) . Chronic LOC exceedances for birds consuming a variety of dietary items (RQ values ranged 1.03-23.66).

. Mammals : Acute dose- and dietary- based LOC exceedances for multiple size classes and feeding guilds of mammals; both acute and chronic LOCs have been exceeded. Conclusion: No Risks of Concern Certainty: Low Conclusion: Risks of Concern Identified Certainty: Low
Terrestrial Invertebrates : No toxicity was observed in the only available study (adult acute contact) for honey bees. Toxicity to larval life

- stages is unknown; therefore, risk is presumed in the absence of acute and chronic oral toxicity data for larvae. In addition, toxicity data evaluating the oral route of exposure on an acute and chronic basis is also needed for the adult honey bees as well. Data are also needed to examine residues of endothall in pollen and nectar.

### 9 

## b. Drinking Water Exposure Assessments

The most recent drinking water exposure assessment conducted for endothall was completed for the new use on apple trees (DP 404321, September 2012). The report has indicated that the irrigation water uses will provide the most conservative drinking water values and designate the Maximum Concentration Level (MCL) of 0.1 mg/L as the maximum value. The estimated drinking water concentrations (EDWC) were 100  g/L for the acute (peak) and 31  g/L for the chronic (annual average). 

## c. Clean Water Act Programs

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 welfare that 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 standards. An Aquatic Life Ambient Water Quality Criteria document has not been published for endothall (see url: http://www.epa.gov/waterscience/criteria/ ).

The Office of Pesticide Programs (OPP) publishes aquatic life benchmarks for freshwater species based on toxicity values for the most sensitive species from the most recent risk assessments. Theaquatic life benchmarks have been published for endothall (acid, dipotassium salt and N,Ndimethylalkylamine salt; Table 4 ).

Table 4. Aquatic Life Benchmarks Published for Endothall

Endothall Form Fish (  g/L) Invertebrates (  g/L) Acute Chronic Acute Chronic
Acid 24500 1300 46000 <2200 Dipotassium salt 4576 1790 31900 N,N-dimethylalkylamine 7.5 56 6 2.3 

### (See url: http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm#benchmarks ). Endothall is not identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

. No Total Maximum Daily Load (TMDL) criteria have been developed for endothall, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=88 5&p_pollutant_group_name=PESTICIDES

. 

## 5. Environmental Fate and Transport

The endothall salts dissociate at environmentally relevant pH levels and all three endothall forms will be found in the environment. Endothall has two carboxylic acid groups and hence can dissociate one or two protons. Due to the high water solubility and low Henry’s La w constant, the volatilization will not be a concern.

### 10 The mobility of the endothall compound is highly sensitive to pH. In batch equilibrium studies (MRID 41616404) on endothall acid, Freundlich K ads 

### values were 0.15, 0.80, 0.56, and 7.94 on loamy sand, sandy loam, clay loam, and silt loam respectively. These mobility values are inversely related to soil pH, as evidenced by soils with a pH of >6.1-6.2 demonstrating low sorption (0.15- 0.80). A soil with a pH of 6.1-6.2 or less will be more tightly sorbed to the soil.

Endothall degrades only via biotic processes such as aerobic metabolism, and not as the result of abiotic processes such as hydrolysis and photolysis. The submitted laboratory studies indicate that the amine salt (MRID 44578401) and di-potassium salt (MRID 42289106) forms of endothall are stable to hydrolysis at pH 5, 7 and 9. The acid form of endothall was also found to be stable to aqueous photolysis in a laboratory study (MRID 42289205, 42641201). In aquatic environment, the endothall acid is negatively charged. It will be repelled from the soil and sediment and be found primarily in the water column. The potassium and amine cations are positively charged and will bind to most sediments and soils. In an aerobic soil metabolism study, the dipotassium salt of endothall degraded with a half-life of 14.5 days in Huntington sandy loam soil (MRID 44949401). In aerobic lake water over flooded silt loam sediment, endothall dipotassium salt degraded with a half-life of 10 days (MRID 42618901). There were no major degradates. Endothall acid is not expected to be present for adequate time to result in long-term exposure.

In terrestrial field dissipation studies residues of endothall were not persistent. Dipotassium endothall applied to sugar beet fields in California and Pennsylvania (loam and silty clay loam soils, respectively) dissipated from the upper 4 inches of soil with half-lives of <7 days and 9 days. Similarly, endothall (N,N-dimethyl alkyl amine salt) applied to potato fields in California and Pennsylvania (loam and silty clay loam soils, respectively) dissipated from the upper 4 inches of soil with half-lives of 12.6 and 19.2 days, respectively.

Numerous aquatic dissipation studies ranging from laboratory, greenhouse, ponds (partial and whole treatment), lakes, and reservoirs demonstrate dissipation half-lives of 0.5 to 30 days. The persistence of endothall in the aquatic environment is consistent regardless of the type of study. For laboratory studies, the median half-life of endothall was 8.5 days (4.1-30 days). For ponds and lakes, the median half-lives were 4.1 days (0.5-20 days) and 1.2 days (0.24-8.5 days), respectively.

The chemical properties and environmental fate parameters are tabulated in Table 5

. Table 5. Chemical Properties and Environmental Fa te Parameters of Three Endothall Products
Acid Dipotassium N,N-dimethylalkylamine CAS Registry Number #145-73-3 #2164-07-0 #66330-88-9 Physical state solid liquid or solid (granular)* liquid or solid (granular)* Water solubility (g/ml @25 q C) >11 >65 >50

Octanol:Water partition coefficient (K ow @25 q C) <1 <1 <1

Dissociation Constant (pKa 1 , pKa 2 ) 4.32, 6.22 4.16, 6.14 4.24, 6.04

pH 2.7 6.5 - 7.5* 4.4 - 4.6*

### 11 Acid Dipotassium N,N-dimethylalkylamine Vapor pressure (torr@24.3 q C) 3.92 x 10 -5 3.92 x 10 -5 2.09 x 10 -5 Henry’s Law Constant (atm-m 3 /mole) < 6.64 x 10 -10 < 1.58 x 10 -10 < 9.53 x 10 -11
Hydrolysis No Data acid stable at pH 5, 7, & 9 (MRID 42289106) acid stable at pH 5, 7, & 9 (MRID 44578401)
Direct Aqueous Photolysis does not absorb light >290nm (MRID 42289205) does not absorb light >290nm (MRID 42289205) does not absorb light >290nm (MRID 42289205)
Soil Photolysis (half -life, days) 48.7 (irradiated) 100.4 (dark) 1 (MRID 42641202) 4 No Data No Data

Aerobic Soil Metabolism (half-life, days) No Data 14.5 (sandy loam) 2 (MRID 44949401) No Data

Anaerobic Aquatic Metabolism (half -life, days) No Data 9.0 (silt loam) 3 (MRID 42903901) 4 No Data

Aerobic Aquatic Metabolism (half-life, days) No Data 10.0 (flooded silt loam) 2 (MRID 42618901) No Data

K d-ads / K d-des (ml/g) 0.15/0.0 (loamy sand) 0.80/4.3

(sandy loam) 0.56/2.57

(clay loam) 7.94/37.25

(silt loam) (MRID 4161604) No Data No Data

Soil Dissipation No Data CA: <7.0 (loam) PA: <9.0 (silty clay loam) (MRID 42670101) CA: 13 (loam) PA: 19 (silty clay loam) (MRID 42670201) Sediment Dissipation (half-life, days) No Data 8.9 (MRID 44093403) 4 2.5-3.4 (MRID 44093402) 4 No Data

Aquatic Dissipation (half -life, days) No Data 0.8 (lake water) (MRID 44093403) 4

0.4 (uncontained) 5.4 -8.5 (contained (MRID 44093402) 4 <24h in sediment 5 Max. residues of 7.7, 5.4, 4.6, 4.0, and 3.4 ug/L; 0, 3.6, 10, 13, and 15 miles from treatment canal in CO. (MRID 44820103)

Fish Accumulation (BCF) No Data 0.08x (edible) 0.35x (whole) (MRID 4264001) No Data

*dependent on commercial formulation

1 Non-volatile unidentifiable degradates (18% of applied)

2 Unextractable degradates and CO 2 3 mono-and di- methyl ester degradates

### 12 o o

o o [ NH(CH 3 ) 2 (CH 2 ) n (CH 3 )] + [ NH 

### O

-

n=7-17 4 Study unacceptable

5 endothall acid and monohydrate degradates



### The structures of all three endothall products and environmental degradates are listed in Table 6.

Table 6. Chemical Structure of All Three Endoth all Products and Environmental Degradates
Product Name Chemical Structure
Parent Endothall Products

Endothall Acid
7- Oxabicyclo (2,2,1)heptane-2,3- dicarboxylic acid MW: 186.2 g/mole
Molecular Formula: C 8 H 10 O 5

Endothall, Dipotassium salt
7 -Oxabicyclo (2,2,1)heptane-2,3-dicarboxylic acid dipotassium salt MW: 262.3 g/mole
Molecular Formula: C 8 H 8 K 2 O 5

Endothall, mono (N,N,

- dimethyl alkyl amine) salt MW: 228. 1 g/mole



### Minor Environmental Degradates

Endothall Monomethyl Ester Max. detection 0.03% (aerobic soil metabolism study, MRDI 4494901) Max. detection 4.75% (anaerobic aquatic metabolism study, MRDI 42903901)

Endothall Dimethyl Ester Max. detection 4.75% (anaerobic aquatic metabolism study, MRDI 42903901)



### There is no fate and transport information about the coco-alkylamine cation, which is a part of mono (N,N-dimethylalkylamine) salt of endothall. For this reason, several fate guideline studies are required, in order to better assess the ecological impacts due to coco-alkylamine cation.

### 13 

## 6. Receptors

The toxicity endpoints that will be used in risk assessment for aquatic and terrestrial organisms exposed to endothall are presented in Table 7 through Table 10 below.

Endothall acid is the herbicidal active ingredient in all of the endothall-containing herbicide formulations. The mono N,N-dimethylalkylamine salt has been shown to be substantially more toxic than the acid and dipotassium salt for all aquatic species tested. For example, LC 50 

### s for rainbow trout are 49 mg ae/L, 9 mg ae/L, and 0.1 mg ae/L, respectively, for the three endothall forms. The dimethylalkylamine salt is consistently and substantially (2 orders of magnitude or more) more toxic than the acid and dipotassium salt to aquatic organisms. For both the aquatic and terrestrial assessments, the most sensitive endpoint from the dimethylalkylamine salt or the free acid will be used to assess dimethylalkylamine salt uses. The most sensitive endpoint from the dipotassium salt or the free acid will be used to assess dipotassium salt uses. All endpoints will be expressed in terms of endothall acid equivalents for risk estimation.

In general, endothall acid and the dipotassium salt have similar toxicity values and are slightly to practically non-toxic to aquatic animals on an acute exposure basis. Only a few chronic studies are available for the endothall acid and dipotassium salt; however, chronic effects were seen at substantially lower test concentrations than the LC 50 

### ’ s. The available dipotassium freshwater fish chronic study was not a guideline study, as fertilized rainbow trout eggs and sac fry, were exposed to the chemical for 4hrs followed by clean water for the remainder of the test duration. This study cannot be used to estimate risk to fish on a chronic basis for dipotassium; however, an acceptable freshwater early life-stage study (ELS) is available for the acid, and so a new study for the dipotassium salt is not needed for freshwater fish. No chronic estuarine/marine fish data is available for either the acid or the dipotassium salt. The available chronic daphnid study for endothall acid could not establish a no effect level as significant reductions were noted in length and number of offspring in the lowest test concentration that was tested, 2.2 mg ae/L, when compared to the controls. However, as previously mentioned, the dimethylalkylamine salt is consistently more toxic on an acute and chronic basis to aquatic animals. It is typically highly to very highly toxic on an acute exposure basis, and chronic effects were often seen in the low ug ae/L range for the dimethylalkylamine salt. The available chronic estuarine/marine invertebrate toxicity study for the dimethylalkylamine salt was classified as supplemental, and not upgradable because the offspring were not held until test termination for evaluation of mortality, sex ratios, and growth, offspring were apparently observed for abnormalities at the time of counting, and then they were discarded. It should be noted that there may be some small differences in endpoints from previous risk assessments, it was determined after review that the conversion to acid equivalent was incorrect, and therefore the endpoints were updated accordingly. Endpoints affected were the fathead and sheepshead minnow early life-stage toxicity tests, the daphnid, and mysid life-cycle chronic toxicity tests; as well as the two sediment toxicity tests, (a summary of the data is in Table 7 ).

Aquatic plant studies are available for only the dipotassium and mono (N,N-dimethylalkylamine) salt of endothall; no aquatic plant toxicity data are available for the endothall acid. Again the dimethylalkylamine salt is substantially (2 orders of magnitude or more) more toxic than the dipotassium salt to aquatic non-vascular plants; however it is similarly toxic to aquatic vascular plants. There are no aquatic plant toxicity data available for endothall acid; aquatic plant toxicity

### 14 data are only available for the dipotassium salt and the mono (N,N-dimethylalkylamine) salt, (a summary of the data is in Table 8 ).

Endothall acid is moderately toxic to avian species on an acute oral basis, practically non-toxic to avian species on a sub-acute dietary basis, highly toxic to mammals on an acute oral basis; and practically non-toxic to honeybees (LD 50 

### >11  g/bee). The dipotassium salt is moderately toxic to avian species on an acute oral basis, slightly toxic to avian species on a sub-acute dietary basis, highly toxic to mammals on an acute oral basis, and practically non-toxic to honeybees (LD 50 

### >11
 g/bee; although the test product was given (Aquathol K, 28.6% ae) and it is not clear if any additional adjustments are needed to present the data as ae). The mono (N,N-dimethylalkylamine) salt is moderately toxic for avian species on an acute oral basis, slightly on a sub-acute dietary basis, highly toxic to mammals on an acute oral basis, and practically non-toxic to honeybees (LD 50 

### >11  g/bee; although the test product was given (Hydrothol 191 23.4% ae) it is not clear if any additional adjustments are needed to present the data as ae). Due to the uncertainty surrounding the honeybee data, and in accordance with the new pollinator guidance, a full suite of honeybee data are being requested for the dipotassium salt and the mono (N,N-dimethylalkylamine) salt) (a summary of the available data is in Table 9 and the requested data are in Section 9 b ).

Birds exposed to endothall acid on a chronic basis showed effects on early embryonic mortality in the offspring of mallard ducks. There was a high incidence of midterm eggs, a high number of eggs cracked, and a loss of an entire hatch due to incubator malfunction that can be indicative of an atypical population and masked effects during the study, this study was considered scientifically sound, but as a result of these issues, was classified as supplemental, and does not fulfill guidelinerequirements for an avian reproduction toxicity study. Birds exposed to the mono (N,Ndimethylalkylamine) salt on a chronic basis showed effects on adult female body weight gain in all treatment levels for mallard ducks; and a no effect level could be established. There were no effects to bobwhite quails exposed to mono (N,N-dimethylalkylamine) salt on a chronic basis. No data was submitted for dipotassium salt for chronic toxicity to birds, and there was no chronic toxicity to mammals for endothall acid, the dipotassium salt or the mono (N,N-dimethylalkylamine) salt, (a summary of the data is in Table 9 ).

The only available mammalian 2-generation reproduction study for endothall utilized a formerly registered salt of endothall (disodium salt), and it was determined by HED that this data was acceptable to fulfill mammalian data needs, and no additional data would be requested for other forms of endothall. The study showed effects to mammals based on effects to the offspring, including decreased pup weight observed at day 0 of F 1 

### and F 2 

### a generations. Parental systemic toxicity endpoints affected were the proliferative lesions of the gastric epithelium for both sexes, (a summary of the data is in Table 9 ).

There are no terrestrial plant toxicity data available for endothall acid; terrestrial plant toxicity data are only available for the dipotassium salt and the mono (N,N-dimethylalkylamine) salt, (a summary of the data is in Table 10 ).

Terrestrial plant toxicity data, both seedling emergence and vegetative vigor, are available for the dipotassium salt of endothall and the mono (N,N-dimethylalkylamine) salt of endothall. For the dipotassium salt, the vegetative vigor study was the more sensitive endpoint. The EC 25 

### and NOAEC for lettuce ( Lactuca sativa ) was 0.011 and 0.005 lb ae/acre, respectively, based on vegetative vigor shoot weight. For the mono (N,N-dimethylalkylamine) salt of endothall, the

### 15 vegetative vigor study was also the most sensitive endpoint. The EC 25 

### and NOAEC for perennial ryegrass ( Lolium perenne ) was 0.004 and 0.00006 lb ae/acre, respectively, based on vegetative vigor shoot length, (a summary of the data is in Table 10 ). 

## a. Effects to Aquatic Organisms

Table 7. Summary of the Most Sensitive Acute and Chronic Toxicity Data for Aquatic Animals Exposed to Endothall Acid, or the Dipotassium or Mono (N,N-dimethylalkylamine) Salts of Endothall

Species Test Substance

(% ae) Acute Toxicity Chronic Toxicity LC 50 /EC 50 (mg ae /L) (Toxicity Classification) MRID (Study Classification) NOAEC/LOAEC (mg ae/L) (Endpoints) MRID (Study Classification)

Rainbow trout ( Oncorhynchus mykiss ) Acid (77.9% ae) 49.0 (slightly toxic) 42327702 (Acceptable) ND ND

Dipotassium (28.6% ae) 9.152 (moderately toxic) 40098001 (Supplemental) 1.79/3.58 (percent eggs hatch) 1 00095812 (Supplemental)

Mono (23.4% ae) 0.131 (highly toxic) 40098001 (Supplemental) ND ND

Fathead minnow ( Pimephales promelas ) Acid (91.2% ae) ND ND 1.3/2.6 (wet weight & length) 43295401 (Acceptable)

Mono (Acute: 23.4% ae; Chronic: 23.5% ae) 0.175 (highly toxic) 40098001 (Supplemental) 0.046/0.098 (survival at test termination) 0.098/0.019 (percent hatch, length, & wet weight) 43276501 (Acceptable)

Waterflea ( Daphnia
magna ) Acid (Acute: 77.9% ae; Chronic: 91.2% ae) 92.0 (slightly toxic) 42359702 (Acceptable) <2.2/2.2 (total body length & number offspring/female) 2 43007801 (Supplemental) Dipotassium (28.6% ae) 70.7 (slightly toxic) 42695403 (Acceptable) ND ND

Mono (23.4% ae) 0.084 (very highly toxic) 00035242 (Acceptable) 0.055/0.11 (reproduction) 0.11/0.23 (young survival, length & weight) 43437901 (Acceptable)

Waterflea ( Ceriodaphnia Dubia ) Mono (23.4% ae) 48-hr LC 50 = 0.11 (highly toxic) Keller et al., 1988 (Quantitative) 0.0023/0.0058 (Survival & number of broods) Keller et al., 1988 (Quantitative)

Sheepshead minnow ( Cyprinodon variegatus ) Acid (77.9% ae) 110 (practically non-toxic) 42914102 (Acceptable) ND ND

Dipotassium (28.6% ae) 103 (practically non-toxic) 42695405 (Acceptable) ND ND

Mono (23.5% ae) 0.823 (highly toxic) 43196903 (Acceptable) 0.006/0.0014 (dry weight) 47563701 (Acceptable)

### 16 Species Test Substance

(% ae) Acute Toxicity Chronic Toxicity LC 50 /EC 50 (mg ae /L) (Toxicity Classification) MRID (Study Classification) NOAEC/LOAEC (mg ae/L) (Endpoints) MRID (Study Classification)

Eastern oyster ( Crassostrea virginica ) Acid (91.2% ae) 43 (slightly toxic) 42895201 (Acceptable) -- -- Dipotassium (28.6% ae) 99.1 (slightly toxic) 42695404 (Acceptable) -- --
Mono (23.5% ae) 0.161 (highly toxic) 43550201 (Acceptable) -- --

Mysid ( Americamysis bahia ) Acid (91.2% ae) 39 (slightly toxic) 42914101 (Acceptable) ND ND Dipotassium (28.6% ae) 78 (slightly toxic) 42695406 (Acceptable) ND ND

Mono (23.5% ae) 0.517 (highly toxic) 43210001 (Acceptable) 0.014/0.028 (number of offspring per female & number of offspring

per female per reproductive day) 47563701 (Supplemental)

Midges ( Chironomus

tentans ) Mono (23.4% ae) -- -- NOAEC = 48.2 mg ae/kg sediment (21.2 mg ae/kg pore water)

(None, not biologically relevant) 47742801 (Acceptable)

Amphipods ( Leptocheirus plumulosus ) Mono (23.4% ae) -- -- NOAEC = 9.8 mg ae/kg sediment (6.4 mg ae/kg pore water) (None) 47742802 (Acceptable)

ND = No Data; -- = Not applicable

1 A non-guideline study, conducted on fertilized rainbow trout eggs and sac fry; the fish were exposed for 4-hours to AquatholK. At the highest concentration (12.5 mg/L), the percent hatch was 72.2% vs. 84.4% in controls. No protocol was provided.

2 The NOAEC could not be established, as significant reductions were noted in length and the number of offspring in the lowest test concentration that was tested, 2.2 ppm a.e., when compared to the controls.



### Table 8. Summary of the Most Sensitive Toxicity Data for Aquatic Plants Exposed to Endothall Acid, or the Dipotassium or Mono (N,N-dimethylalkylamine) Salts of Endothall 1

Species Test substance

(% ae) Endpoint (mg ae/L) Effect (MRID; Study Classification)

Vascular Plants Duckweed ( Lemna gibba ) Dipotassium (28.6% ae) 14-d EC 50 = 0.61 14-d NOAEC = 0.0046 Frond counts (42396406; Acceptable)

Duckweed ( L . gibba ) Mono (23.6% ae) 7-d EC 50 = 0.74 7-d NOAEC (EC 05 ) = 0.15 Inhibition in growth rate based on frond count after 7-days. (44949402; Acceptable) Non-Vascular Plants Green algae ( Kirchneria subcapitata

, formerly Selenastrum capricornutum ) Mono (23.6% ae) 96 hr EC 50 = 0.0023 96 hr NOAEC (EC 05 ) = 0.00054 Inhibition in growth rate based on cell counts after 96 hours. (44949203; Acceptable)

### 17 Species Test substance

(% ae) Endpoint (mg ae/L) Effect (MRID; Study Classification)

Freshwater Diatom ( Navicula pelliculosa ) Mono (23.6% ae) 96 hr EC 50 = 0.0072 96 hr NOAEC = 0.0023 Inhibition in growth rate based on cell counts after 96 hours. (44949201; Acceptable)

Marine Diatom ( Skeletonema costatum ) Mono (23.6% ae) 96 hr EC 50 = 0.022 96 hr NOAEC (EC 05 ) = 0.0037 Inhibition in growth rate based on cell counts after 96 hours. (44976701; Acceptable)

Blue -green algae ( Anabaena flos -aquae ) Mono (23.6% ae) 96 hr EC 50 = 0.040 96 hr NOAEC = 0.024 Inhibition in growth rate based on cell counts after 96 hours. (44949202; Acceptable)

Blue -green algae ( A . flos-aquae ) Dipotassium (28.6% ae) 120 hr EC 50 = 1.56 120 hr NOAEC (EC 05 ) = 0.071 Inhibition in growth rate based on cell counts after 120 hours.

(44408801; Acceptable) Green algae ( K .subcapitata ) Dipotassium (28.6% ae) 120 hr Tier I study, EC 50 >7.0 mg ae/L; 2% reduction in growth Effects were less than 50% (44392801; Acceptable)

Freshwater Diatom ( N . pelliculosa ) Dipotassium (28.6% ae) 120 hr Tier I study, EC 50 > 7.8 mg ae/L; 42% reduction in growth 42% reduction in growth, effects were less than 50% (44392802; Acceptable)

Marine Diatom ( S . costatum ) Dipotassium (28.6% ae) 120 hr Tier I study, EC 50 > 6.4 mg ae/L; 23% reduction in growth 23% reduction in growth; Effects were less than 50% (42396404; Acceptable)

1 No aquatic plant toxicity data are available for endothall acid. 

## b. Effects to Terrestrial Organisms

Table 9. Summary of the Most Sensitive Acute and Chronic Toxicity Data for Terrestrial Animals Exposed to Endothall Acid, or the Dipotassium or Mono (N,N-dimethylalkylamine) Salts of Endothall

Species Test substance

(% ae) Acute Toxicity Chronic Toxicity

LD 50 (mg ae /kg bw) (Toxicity Classification) LC 50 (mg ae /kg diet (ppm ae )) (Toxicity Classification) MRID (Study Classification) NOAEC/ LOAEC (mg ae /kg diet (ppm ae )) (Endpoints) MRID (Study Classification)

Bobwhite Quail ( Colinus virginianus ) Acid (75% ae &

84% ae) 500 (moderately toxic) >10,000(practically nontoxic) 00074220 (Supplemental) & 00116270 (Acceptable) ND ND

Dipotassium (28.6% ae) -- >2860 (slightly toxic) 00035239 (Acceptable) ND ND

Mono (23.4% ae) 173 (moderately toxic) >1170 (slightly toxic) 00035237 (Acceptable) & 43167901 (Acceptable) 613/>613 (No effects) 47861102 (Acceptable)

### 18 Species Test substance

(% ae) Acute Toxicity Chronic Toxicity

LD 50 (mg ae /kg bw) (Toxicity Classification) LC 50 (mg ae /kg diet (ppm ae )) (Toxicity Classification) MRID (Study Classification) NOAEC/ LOAEC (mg ae /kg diet (ppm ae )) (Endpoints) MRID (Study Classification)

Mallard Duck ( Anas platyrhynchos ) Acid (83.6% ae &

84% ae) 229 (moderately toxic) >10,000(practically nontoxic) 00160000 (Acceptable) & 00116271 (Acceptable) 50 (early embryonic mortality) 42507301 (Supplemental)

Dipotassium

(29.5% ae) 61.6 (moderately toxic) >2860 (slightly toxic) 42359501 (Acceptable) & 00035238 (Acceptable) ND ND

Mono (23.4% ae) 91 (moderately toxic) >1170 (slightly toxic) 42359601 (Supplemental) & 43167902 (Acceptable) <82.4/ 82.4 (adult female body weight gain) 47861101 (Supplemental)

Laboratory rat ( Rattus norvegicus ) Acid (81.1% ae) 44.4 (F) (highly toxic) -- 42289201 (Acceptable) ND ND Acid (89.5% ae) Acute rat inhalation LC 50 = 1.27 mg/L (M); 2.2 mg/L (F) (4 hrs) 42169501 (Acceptable)

Di sodium (19.9% ae) ND ND ND 150/30 ppm ae (9.4/2 mg

ae /kg/day) (decreased pup body weight) 43152101; 43629301 (Acceptable)

Dipotassium

(28.6% ae) 24.3 (M) (highly toxic) -- 42338901 (Acceptable) ND ND Acute rat inhalation LC 50 = 0.53 mg ae/L (M); 0.62 mg ae/L (F) (4 hrs) 42407101 (Acceptable)

Mono (23.4% ae) 49.1 (F) (highly toxic) -- 42774001 (Acceptable) ND ND Acute rat inhalation LC 50 = 0.50 mg ae/L (M); 0.57 mg ae/L (F) (4 hrs) 42560901 (Acceptable)

Honey Bee ( Apis mellifera ) Acid >11  g/bee (p ractically non-toxic) --

44038201 (Acceptable) -- --
Dipotassium (Aquathol K,

28.6% ae) >11  g/bee (p ractically non-toxic) -- -- --

Mono (Hydrothol 191, 23.4% ae) >11  g/bee (p ractically non-toxic) -- -- --

ND = No Data; NA = Not Available; -- = Not applicable

### 19 Table 10. Summary of the Most Sensitive Toxicity Data for Terrestrial Plants (Tier II) Exposed to the Dipotassium or Mono (N,N-dimethylalkylamine) Salts of Endothall 1

ND = No Data; NA = Not Available; -- = Not applicable

1 No terrestrial plant toxicity data are available for endothall acid.

2 EC 05 values were calculated since the NOAEC could not be determined. 

## c. Ecological Incidents

The ecological incident information system (EIIS) is an OPP database that houses ecological incidents that have been reported to the Agency. When available, EIIS includes date and location of an incident, type and magnitude of effects observed in various species, use(s) of pesticides known or suspected of contributing to the incident, and results of any chemical residue analysis or other analyses conducted during incident investigation. EIIS incidents are categorized according to the Plant Type Species / Test Substance (% ae) EC 25 (lb ae /acre) NOAEC 2 (lb ae /acre) Most Sensitive Endpoint MRID/ Study Classification
Seedling Emergence

Monocots Ryegrass ( Lolium perenne )/ Dipotassium (28.6% ae) 0.03 5 0.005 (EC 05 ) Length 42396405 & 44392803 (Acceptable) Ryegrass Mono (23.4% ae) 0 .033 0.014 Length 43870401 (Acceptable)

Dicots Lettuce ( Lactuca sativa )/ Dipotassium (28.6% ae) 0.0 18 0.013 Length 42396405 & 44392803 (Acceptable) Soybean ( Glycine max ) / Dipotassium (28.6% ae) 0.033 0.0 099 (EC 05 ) Length 42396405 & 44392803 (Acceptable)

Lettuce / Mono (23.4% ae) 0.016 0.003 Shoot length 43870401 (Acceptable) Vegetative Vigor

Monocots Ryegrass /Dipotassium (28.6% ae) 0.004 0.00006 (EC 05 ) Shoot Length 42396405 & 44392803 (Acceptable) Oat ( Avena sativa )/ Dipotassium (28.6% ae) 0.065 0.114 (EC 05 ) Shoot weight

Oat /Mono (23.4% ae) 0.05 6 0.028 (EC 05 ) Root weight 43870401 (Acceptable)

Plant Type Species / Test Substance (% ae) EC 25 (lb ae /acre) NOAEC 2 (lb ae /acre) Most Sensitive Endpoint MRID/ Study Classification

Dicots Lettuce /Dipotassium (28.6% ae) 0.011 0.005 (EC 05 ) Shoot weight 42396405 & 44392803 (Acceptable)

Lettuce / Mono (23.4% ae) 0.055 0.017 (EC 05 ) Shoot weight 43870401 (Acceptable) Turnip ( Brassica rapa )/ Mono (23.4% ae) 0.04 5 0.028 Shoot weight

### 20 certainty that the incident resulted from pesticide exposure. The Avian Monitoring System (AIMS) is a database administered by the American Bird Conservancy that contains publicly available data on reported avian incidents involving pesticides. Many of the incidents listed in this database are also in the EIIS. The Aggregate Incident Reports database is an Agency database that may contain minor wildlife and plant incidents for chemicals.

Reviews of the Ecological Incident Information System (EIIS, version 2.1.1), the Avian Incident Monitoring System (AIMS) 2 

### , and the EPA Incident Data System (IDS, Aggregate Incident Reports database) were conducted on April 7, 2015; looking under all PC codes related to endothall; endothall acid, disodium dipotassium and mono (N,N-dimethylalkylamine) salts of endothall; 038901, 038903, 038904 and 038905, respectively). There were three ecological incidents reported in EIIS listed under endothall acid (I015726-001, B0000-231-03 and I013884-031), and two incidents listed under the mono (N,N-dimethylalkylamine) salt of endothall (I010688-001 and I014385-001); summarized in Appendix B . One incident (I015726-001) involved aquatic invertebrates (mussels); two incidents (B0000-231-03 and I010688-001) involved fish, and two incidents (I013884-031 and I010688-001) involved terrestrial plants. The one incident involving aquatic invertebrates was of an unknown legality and occurred in the presence of another chemical as well, diuron; endothall was listed as a possible cause of the incident. The two incidents that involved fish were from accidental misuses of endothall, resulting from a spill (near a drain; B0000- 231-03) and increased application in the presence of higher temperatures (I010688-001). One incident was identified to be the highly probable cause of the incident (B0000-231-03); and the second incident was identified to be the probable cause of the incident. The two incidents on terrestrial plants involved registered uses (I013884-031 and I014385-001) of endothall. The identified registered use incident on terrestrial plants (I013884-031) occurred in the presence of additional pesticides, and endothall is listed as a possible cause of the incident. The second identified registered use incident in the terrestrial environment was the result of a registered use on ponds (I014385-001) where two birds were found dead, one egret 3 days after application and one pelican 7 days after application; however, chemical analysis on the birds or the pond were not reported. There were no reported incidents in the AIMS database for endothall.

There were a total of 4 minor incidents in the Aggregate Incident Reports database for endothall (looking under all PC codes related to endothall; endothall acid, disodium (because of the mammalian data), dipotassium and mono (N,N-dimethylalkylamine) salts of endothall. One minor wildlife incident was reported in 2003 (014385-00001) for the Hydrothol 191 soluble concentrate formulation of endothall (mono (N,N-dimethylalkylamine) salt); one minor plant incident was reported in 2003 (014705-00001) for the Hydrothol 191 granular formulation of endothall (mono (N,N-dimethylalkylamine) salt); one minor wildlife incident was reported in 2004 (015437-00001) for the Aquathol K soluble concentrate formulation of endothall (dipotassium salt); and one minor wildlife incident was reported in 2010 (022510-00007) for the EVAC soluble concentrate formulation of endothall. The lack of reported incidences should not be construed as an absence of incidents. Incident reports for non-target organisms typically provide information only on mortality events and plant damage. Sublethal effects in organisms such as abnormal behavior, reduced growth and/or impaired reproduction are rarely reported, except for phytotoxic effects in terrestrial plants.

2 http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm

### 21 

## 7. Exposure Pathways of Concern

The environmental fate properties and use patterns of endothall indicate that direct spray, spray drift, and runoff represent potential transport mechanisms to aquatic and terrestrial organisms. Theconceptual model will consider endothall acid, dipotassium salt and mono (N,Ndimethylalkylamine) salt as the residues of concern.

Drinking water and inhalation exposure pathways were screened using the SIP (Screening Imbibition Program, version 1.0) and STIR (Screening Tool for Inhalation Risk, version 1.0) screening methods. Drinking water exposure alone was determined to be a potential pathway of concern for avian and mammalian species on an acute and chronic basis for endothall acid and for the dipotassium and mono (N,N-dimethylalkylamine) salts of endothall ( Tables 11 - 16 ). However, due to the very high solubility of all three compounds (endothall acid, dipotassium salt and dimethylalkylamine salt; >11,000,000->65,000,000 mg/L) the model is likely over estimating exposure. As a result, EFED will explore other methods to look at this exposure route at the time of the risk assessment. The inhalation pathway was determined not to be a potential exposure pathway of concern (no LOC exceedances were found for STIR). Outputs for each model are located in Appendix C . SIP and STIR are described in detail at: http://www.epa.gov/oppefed1/models/terrestrial/index.htm

.

Table 11. SIP Mammalian Results

– Endothall Acid Parameter Acute Chronic Upper bound exposure (mg ae/kg-bw) 1892000 1892000 Adjusted toxicity value (mg ae/kg-bw) 34 7.23 Ratio of exposure to toxicity 55401 261683

Conclusion* Exposure through drinking water alone is a potential

concern for mammals Exposure through drinking water alone is a potential

concern for mammals



### Table 12. SIP Avian Results

– Endothall Acid Parameter Acute Chronic Upper bound exposure (mg ae/kg-bw) 8910000 8910000 Adjusted toxicity value (mg ae/kg-bw) 119 2.48 Ratio of exposure to acute toxicity 74935 3591832

Conclusion* Exposure through drinking water alone is a potential concern for birds Exposure through drinking water alone is a potential concern for birds *Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non -target animals.

** Due to the very high solubility of this compound, the model may be over estimating exposure. As a result, EFED will explore other methods to look at this exposure rout e at the time of the risk assessment.

### 22 Table 13. SIP Mammalian Results

– Dipotassium Salt of Endothall Parameter Acute Chronic Upper bound exposure (mg ae/kg-bw) 11180000 11180000 Adjusted toxicity value (mg ae/kg-bw) 18.7 7.23 Ratio of exposure to toxicity 598162 1546311

Conclusion* Exposure through drinking water alone is a potential

concern for mammals Exposure through drinking water alone is a potential

concern for mammals



### Table 14. SIP Avian Results

– Dipotassium Salt of Endothall Parameter Acute Chronic Upper bound exposure (mg ae/kg-bw) 52650000 52650000 Adjusted toxicity value (mg ae/kg-bw) 32 0.0000 Ratio of exposure to acute toxicity 1646121 0.0000

Conclusion* Exposure through drinking water alone is a potential concern for birds Due to insufficient data, risk cannot be precluded

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non -target animals.

** Due to the very high solubility of this compound, the model may be over estimating exposure. As a result, EFED will explore other methods to look at this exposure route at the time of the risk assessment.



### Table 15. SIP Mammalian Results

– Mono (N,N-dimethylalkylamine) Salt of Endothall Parameter Acute Chronic Upper bound exposure (mg ae/kg-bw) 8600000 8600000 Adjusted toxicity value (mg ae/kg-bw) 38 7.23 Ratio of exposure to toxicity 227719 1189470

Conclusion* Exposure through drinking water alone is a potential

concern for mammals Exposure through drinking water alone is a potential

concern for mammals



### Table 16. SIP Avian Results

– Mono (N,N-dimethylalkylamine) Salt of Endothall Parameter Acute Chronic Upper bound exposure (mg ae/kg-bw) 40500000 40500000 Adjusted toxicity value (mg ae/kg-bw) 47 4.09 Ratio of exposure to acute toxicity 857152 9906863

Conclusion* Exposure through drinking water alone is a potential concern for birds Exposure through drinking water alone is a potential concern for birds *Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non -target animals.

** Due to the very high solubility of this compound, the model may be over estimating exposure. As a result, EFED will explore other methods to look at this exposure route at the time of the risk assessment.



### Exposure from release of cooling tower water is estimated using a Down the Drain (DtD) module from E-FAST. A screening-level DtD analysis has not been performed since such an analysis is appropriate only for uses of antimicrobial pesticides that would be released to domestic waste water treatment plants. Since N,N-amine treated water can be released through industrial treatment

### 23 facilities, the screen is not appropriate. Chemicals coming into a WWTP can take roughly a day to go through the facility and be released to surface waters if they are not degraded or sorbed within the facility. A DtD analysis will be conducted for the registration review risk assessment. Output is reported as the number of days per year the concentration of concern is exceeded for each type of organism which may be exposed.



## 8. Analysis Plan

In addition to the need for honeybee data, there is the need for data to evaluate chronic toxicity to aquatic animals (freshwater and saltwater), acute toxicity to passerine species, chronic toxicity to birds, and phytotoxicity to aquatic plants.



## a. Stressors of Concern

i. Ecological Risk Assessment

For the endothall ecological risk assessment, the stressors of concern in this assessment is primarily the dimethylalkylamine salt for the aquatic assessment. The dimethylalkylamine salt is consistently and substantially (2 orders of magnitude or more) more toxic than the acid and dipotassium salt to aquatic organisms. Therefore, the dimethylalkylamine salt data will be used to assess risks to aquatic organisms. However, data on the acid and dipotassium salt will also be used when the dimethylalkylamine salt shows risks that are above concern levels. If the dimethylalkylamine salt does not present risks of concern, then risks from the endothall acid or dipotassium salt will not need to be quantified. For the terrestrial assessment, the stressors of concern are the endothall acid, dipotassium salt, and dimethylalkylamine salt; examining the most sensitive endpoints of all ecological studies as converted to endothall acid equivalents.

ii. Drinking Water

EPA office of water has identified endothall may cause health problems in the water supply and set a maximum contaminant level (MCL) of 0.1 mg/L, see the following link; http://water.epa.gov/drink/contaminants/basicinformation/endothall.cfm . This standard is reflected in the most recent drinking water exposure assessment (DP 404321, September 2012).


## b. Measures of Exposure

Past assessments of endothall EFED have used standard available models to evaluate potential exposures to aquatic and terrestrial organisms as described at http://www.epa.gov/oppefed1/models/water/index.htm and http://www.epa.gov/pesticides/science/models_db.htm . The Surface Water Concentration Calculator (SWCC, version 1.106) is currently the model that is typically used to estimate aquatic exposure. T-REX (version 1.5.2), and TerrPlant (version 1.2.2) are currently the models that are typically used to estimate terrestrial exposure.

### 24 i. Available Monitoring Data

Endothall is not an analyte in any of the following water monitoring programs: the California Department of Pesticide Regulation (CDPR) surface water database - http://www.cdpr.ca.gov/docs/emon/surfwtr/surfcont.htm , the USGS NAWQA surface and ground water database - http://cida.usgs.gov/nawqa_queries_public/ , and the USEPA STORET Data Warehouse - http://www.epa.gov/storet/ . Monitoring will be considered in the assessment to the extent that any future data on endothall are available.



## c. Measures of Effect

Toxicity data presented in Section 0 of this problem formulation would be used to calculate risk quotients (RQs). Any additional information submitted by the registrant or found in the open literature prior to conduct of the risk assessment would also be considered. The open literature studies are identified using EPA’s ECOTOXicology database (ECOTOX) (USEPA, 2007a), which employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data can also provide insight into the direct and indirect effects of pesticides on biotic communities from loss of species that are sensitive to the chemicals and from changes in structure and functional characteristics of the affected communities. 

## d. Endangered Species Assessments

Consistent with EPA’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to federally listed threatened and endangered (listed) species from registered uses of pesticides in accordance with the Joint Interim Approaches developed to implement the recommendations of the April 2013 National Academy of Sciences (NAS) report, Assessing Risks to Endangered and Threatened Species from Pesticides . The NAS report outlines recommendations on specific scientific and technical issues related to the development of pesticide risk assessments that EPA and the Services must conduct in connection with their obligations under the ESA and FIFRA. EPA will address concerns specific to endothall in connection with the development of its final registration review decision for endothall

.
In November 2013, EPA, the U.S. Fish and Wildlife Service, National Marine Fisheries (the Services), and USDA released a white paper containing a summary of their joint Interim Approaches for assessing risks to listed species from pesticides. These Interim Approaches were developed jointly by the agencies in response to the NAS recommendations, and reflect a common approach to risk assessment shared by the agencies as a way of addressing scientific differences between the EPA and the Services. Details of the joint Interim Approaches are contained in the November 1, 2013 white paper

, Interim Approaches for National-Level Pesticide Endangered Species Act Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report.

Given that the agencies are continuing to develop and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed species and their designated critical habitat, this ecological problem formulation supporting the Preliminary Work Plan for endothall does not describe the specific ESA analysis, including effects determinations for specific listed

### 25 species or designated critical habitat, to be conducted during registration review. While the agencies continue to develop a common method for ESA analysis, the planned risk assessment for the registration review of endothall will describe the level of ESA analysis completed for this particular registration review case. This assessment will allow EPA to focus its future evaluations on the types of species where the potential for effects exists, once the scientific methods being developed by the agencies have been fully vetted. Once the agencies have fully developed and implemented the scientific methods necessary to complete risk assessments for listed species and their designated critical habitats, these methods will be applied to subsequent analyses of endothall as part of completing this registration review. 

## e. Endocrine Disruptor Screening Program

Endothall was not included in the first group of 67 chemicals issued an order to conduct Tier 1 EDSP testing, but it was included on the second list of chemicals for Tier 1 screening. For additional information the EDSP program, visit http://www.epa.gov/endo/

. 

## 9. Preliminary Identification of Data Gaps

a. Environmental Fate
Table 17 identifies environmental fate studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not further data are needed in order to support risk assessment.

Table 17. Submitted Environmental Fate Data for Endothall

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

835.2120 Hydrolysis 42289106 44578401 Acceptable Yes None

835.2240 Aqueous photolysis 42289205 Acceptable Yes None

835.2410 Soil photolysis 42641202 Acceptable Yes None

835.4100 Aerobic soil metabolism 44949401 Acceptable Yes None

835.4300 Aerobic aquatic metabolism 42618901 Acceptable Yes None

835.4400 Anaerobic aquatic metabolism 42903901 Acceptable Yes None

835.1230 835.1240 Adsorption/ desorption and leaching 41616404 Acceptable Yes None

835.6100 Terrestrial field dissipation (including ECM and ILV) 42670101 42670201 Supplemental Yes None One of the test sit e s is without stability confirmation

.

### 26 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

835.6200 Aquatic field dissipation 44828801 44828802 44820101 44820102 44820103 44093403 44093402 A cceptable Yes None

850.1730 Fish bioconcentration 42644001 Acceptable Yes None



### Data GapsFate Studies are needed to address coco-alkylamine cation (part of mono (N,Ndimethylalkylamine) salt of endothall), including:

o OCSPP 835.2100: Hydrolysis

o OCSPP 835.2240: Aqueous Photolysis

o OCSPP 835.4100: Aerobic Soil Metabolism

o OCSPP 835.4400: Anaerobic Aquatic Metabolism

o OCSPP 835:4300: Aerobic Aquatic Metabolism

o OCSPP 835.1230: Batch Equilibrium
For the DtD analysis

o OCSPP 850.3300: Activated Sludge Respiration Inhibition

o OCSPP 835.3110: Ready Biodegradation

o OCSPP 835.3220: Porous Pot Study

o OCSPP 835.3240: Simulation Test

– Aerobic Sewage Treatment

o OCSPP 835.3280: Simulation Test

– Assess Biodegradability in Wastewater



## b. Effects

Table 18 through Table 24 identify ecological effects studies by MRID for endothall acid, dipotassium, and mono (N,N-dimethylalkylamine) salts of endothall that offer data for each guideline requirement, as well as study classifications and whether further data are needed in order to support risk assessment.

The rationale for additional aquatic data needs are as follows: since the dimethylalkylamine salt is consistently and substantially (2 orders of magnitude or more) more toxic than the acid and dipotassium salt to aquatic organisms, additional data are needed for the acid and/or dipotassium salt to have a complete data set for aquatic toxicity. In addition, there are two previously submitted invertebrate chronic toxicity studies, one for endothall acid and one for the dimethylalkylamine salt, that do not fulfill that data requirement and therefore new data are needed for freshwater and estuarine/marine invertebrates, respectively. If a full suite of aquatic toxicity data was to be completed for the acid, aquatic plant toxicity data would be needed.

For terrestrial species, like the aquatic species, a full suite of dimethylalkylamine salt, and a full suite of either the acid or the dipotassium salt is needed for risk assessment. To have a complete data set, additional information is needed for birds due to the results from previously submitted

### 27studies; a no effect level was not established in the avian reproduction study for mono (N,Ndimethylalkylamine) salt, and an acute passerine study is needed for dimethylalkylamine salt, and either the acid or the dipotassium salt. Again, there are some available mammalian data that utilizes data from other salts ( i.e., disodium) that are no longer registered; this data was deemed acceptable by HED, and it is EFED’s understanding that no additional data for the two-generation mammalian reproduction test has been requested ( Table 23 ).

Although all test materials were practically non-toxic to adult honeybees on a contact exposure basis, it is not clear if any additional adjustments were made to the available data for conversion to endothall acid equivalence. Given this uncertainty and due to the new data requirements for pollinators, a full set of honey bee data is needed for both salts (dipotassium and dimethylalkylamine), as pollinators can potentially be exposed to both test materials in the field. The rationale for additional non-guideline data requested is presented below the tables.

Table 18. Submitted Aquatic Ecological Effects Data for Endothall Acid

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.1010 Freshwater invertebrate acute toxicity 42359702 Acceptable Yes None 00071137 Supplemental

850.1025 850.1035 Saltwater invertebrate acute toxicity 42895201 Acceptable

Yes None 42914101 Acceptable

00074227 Supplemental

00084151 Acceptable

850.1075 Freshwater fish acute toxicity 42327701 Acceptable Yes None 42327702 Acceptable

850.1075 Saltwater fish acute toxicity 42914102 Acceptable Yes None 00074225 Acceptable

850.1300 Freshwater invertebrate life cycle 43007801 Supplemental No Significant effects were observed in the lowest test concentration. Data are needed for either the free acid or dipotassium salt ; and data are already a vailable for the dimethylalkylamine salt.

### 28 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.1350 Saltwater invertebrates life cycle (None) (Not applicable) No No chronic estuarine/marine toxicity data are available for endothall acid. Mo re sensitive endpoint s are available using ae conversion for mono salt ; or

a NOAEC value could be estimated for endothall acid with an ACR and available toxicity data for endothall acid. Data are needed for either the free acid or dipotassium salt; and data

are already available for the dimethylalkylamine salt.

850.1400 Freshwater fish early

- life stage 43295401 Acceptable Yes Chronic toxicity test species for endothall acid was the fathead minnow; however, no acute toxicity test was available for this species for endothall acid.

850.1400 Saltwater fish early

- life stage (None) (Not applicable) No No chronic estuarine/marine toxicity data are available for endothall acid. Data are needed for either the free acid

or dipotassium salt; data are already available for the dimethylalkylamine salt. OR

an acceptable acute fathead minnow study for the acid is submitted, and this can be used to calculate an ACR derived E/M NOAEC.

850.1500 Fish life cycle (None) (Not applicable) Yes None

850.4400 Aquatic plant Toxicity Test using Lemna spp

. (None) (Not applicable) No No aquatic plant toxicity data are available for endothall acid; it is only available for the dipotassium and mono (N,N

dimethylalkylamine) salts of endothall. Data are presented as the ae. No aquatic plant toxicity data are needed for the endothall acid. 850.4500 Algal toxicity (None) (Not applicable)

No 850.4550 Cyanobacteria ( A . flos-aquae ) toxicity (None) (Not applicable)

### 29 Table 19. Submitted Aquatic Ecological Effects Data for the Dipotassium Salt of Endothall

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.1010 Freshwater invertebrate acute toxicity 42695403 Acceptable

Yes None 00084150 Supplemental

40098001 Supplemental

05009242 Acceptable

850.1025 850.1035 Saltwater invertebrate acute toxicity 42695404 Acceptable

Yes None 42695406 Acceptable

00035243 Supplemental

850.1075 Freshwater fish acute toxicity 40098001 Supplemental Yes None 42695401 Acceptable

850.1075 Saltwater fish acute toxicity 42695405 Acceptable Yes None 40098001 Supplemental

850.1300 Freshwater invertebrate life cycle (None) (Not applicable) No No chronic aquatic invertebrate toxicity data are available for the dipotassium salt of endothall. Data are needed for either the dipotassium salt or the free acid ; and data are already available for the dimethylalkylamine salt. 850.1350 Saltwater invertebrates life cycle (None) (Not applicable) No

850.1400 Freshwater fish early -life stage 00095812 Supplemental No Available study was conducted on fertilized rainbow trout eggs and sac fry, the fish were exp osed for 4hr s to AquatholK, and returned to flow -through conditions for the duration of the experiment. This is not a guideline stud y. Data are needed for either the dipotassium salt or the free acid ; data are already available for the dimethylalkylamine salt. However, since acceptable FW data are available for the acid, it is not being requested at this time for the dipotassium salt.

### 30 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.1400 Saltwater fish early

- life stage (None) (Not applicable) No No chronic estuarine/marine fish toxicity data are available for the dipotassium salt or the free acid

. The FW dish data cannot be used to estimate E/M toxicity in the absence of data. Data are needed for either the dipotassium salt or free acid; data are already available for the dimethylalkylamine salt. OR an acceptable acute fathead minnow study for the acid is submitted, and this can be used to calculate an ACR derived E/M NOAEC for the acid. The endpoint can be used for the dipotassium salt.

850.1500 Fish life cycle (None) (Not applicable) Yes None

850.4400 Aquatic plant Toxicity Test using Lemna spp. 42396406 Acceptable Yes None

850.4500 Algal toxicity 42396404 Acceptable Yes None
44392801 Acceptable Yes None
44392802 Acceptable Yes None

850.4550 Cyanobacteria ( A . flos-aquae ) toxicity 44408801 Acceptable Yes None



### Table 20. Submitted Aquatic Ecological Effects Data for the Mono (N,N-dimethylalkylamine) Salt of Endothall

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.1010 Freshwater invertebrate acute toxicity 00035242 Acceptable

Yes None 05009242 Supplemental
40098001 Supplemental

850.1025 850.1035 Saltwater invertebrate acute toxicity 43550201 Acceptable

Yes None 43210001 Acceptable
00035244 Supplemental

00074223 Supplemental

### 31 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.1075 Freshwater fish acute toxicity 40098001 Supplemental

Yes None 43196901 Acceptable

43472801 Acceptable

00084148 Acceptable
00046269 Supplemental

850.1075 Saltwater fish acute toxicity 43196903 Acceptable

Yes None 44700401 Supplemental

00074226 Acceptable

850.1300 Freshwater invertebrate life cycle 43437901 Acceptable Yes None

850.1350 Saltwater invertebrate life cycle 47563701 Supplemental No The study was classified as supplemental because the offspring were not held until study termination for evaluation of mortality, sex ratios, and growth; therefore, the study is not upgradable. A new study is needed to fulfi ll the data requirement for the dimethylalkylamine salt.

850.1400 Freshwater fish early-life stage 43276501 Acceptable Yes None

850.1400 Saltwater fish early-life stage 47563701 Acceptable Yes None

850.1500 Fish life cycle (None) (Not applicable) Yes None

NG Sediment Invertebrate Toxicity 47742801 Acceptable Yes None 47742802 Acceptable

850.4400 Aquatic plant Toxicity Test using Lemna spp. 44949402 Acceptable Yes None

850.4500 Algal toxicity 44976701 Acceptable Yes None
44949203 Acceptable Yes None
44949201 Acceptable Yes None

850.4550 Cyanobacteria ( A. flos -aquae ) toxicity 44949202 Acceptable Yes None

### 32 Table 21. Submitted Terrestrial Ecological Effects Data for Endothall Acid

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.2100 Avian oral toxicity 00074220 Supplemental

No Data are needed on a passerine species for either the free acid or the dipotassium salt; and data are also needed for the dimethylalkylamine salt. 00160000 Acceptable

850.2200 Avian dietary toxicity 00116270 Acceptable Yes None 00116271 Acceptable

850.2300 Avian reproduction 42507301 Supplemental No MRID 42507301 (mallard): the study was scientifically sound, classified as supplemental, but did not fulfill the guideline requirements for an avian reproduction study. MRID 42507302 ( northern bobwhite quail ): the study was recently downgraded to invalid due to high control mortality (22%), crowding of the pens, and at the higher doses birds became more lethargic, as a result there is concern with the reliability of the data presented in the study

. A study for bobwhite quail is needed for either the free acid or the dipotassium s alt; data

are available for the dimethylalkylamine salt , but additional data are also needed for the salt.

870.1100 Mammalian acute oral 42289201 Acceptable Yes None

870.1300 Mammalian
acute inhalation 42169501 Acceptable Yes None

870.3800 Mammalian 2- generation Reproduction (None) (Not applicable) Yes None with endothall acid; test substance is only the disodium salt of endothall; MRID #’s 43152101 and 43629301 (see below).

850.3020 Honey bee adult acute contact toxicity 44038201 Acceptable Yes Based on classification in paper by Atkins, E.L. Division of Agricultural Sciences, University of California. MRID 44038201. A LD 50 of >11 ȝ g/bee was classified as practically non-toxic.

### 33 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.4100 Seedling Emergence

(None) (Not applicable) Yes No terrestrial plant toxicity data are available for endothall acid; it is only available for the dipotassium and mono (N,N

dimethylalkylamine) salts of endothall. D ata are presented as the ae. No terrestrial plant toxicity data are needed for the endothall acid. 850.4150 Vegetative Vigor



### Table 22. Submitted Terrestrial Ecological Effects Data for the Dipotassium Salt of Endothall

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.2100 Avian oral toxicity 42359501 Acceptable No Yes

– a passerine species is needed to fulfill guideline requirements. Tier 1 EECs from past assessments ranged from approx. 161- 1347.45
ppm ae , and the acute LD 50 was 61.6 mg ae/kg-bw and the sub

acute LC 50 was >2860 mg ae/kgdiet. The passerine L D 50 would have to be at least 30

- 220 times greater than the other avian species
to no longer result in an acute listed species LOC exceedance of 0.1. Data are needed for either the dip otassium salt or the free acid; and data are also needed for the dimethylalkylamine salt.

850.2200 Avian dietary toxicity 00035239 Acceptable Yes None 00035238 Acceptable

### 34 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.2300 Avian reproduction (None) (Not applicable) No No avian reproduction toxicity data for the dipotassium salt of endothall are available. Two acceptable avian reproduction studies are needed for either the free acid or the dipotassium salt. Data are available for the mallard duck for the free acid; however, a new bobwhite quail study is needed for the free acid; and data are already available for the dimethylalkylamine salt. Information is needed to fulfill the guideline requirement for the free acid or the dipotassium salt. Therefore, based on the available toxicity data for the acid, a study for bobwhite quail is needed for either the free acid or the dipotassium salt.

870.1100 Mammalian acute oral 42338901 Acceptable Yes None 44319605 Acceptable

870.1300 Mammalian
acute inhalation 42407101 Acceptable Yes None 44319607 Acceptable

870.3800 Mammalian 2- generation Reproduction (None) (Not applicable) Yes None with the dipotassium salt of endothall ; test substance is only the disodium salt of endothall; MRID #’s 43152101 and 43629301 (see below).

850.3020 Honey bee adult acute contact toxicity 44038201 Acceptable No Based on classification in paper by Atkins, E.L. Division of Agricultural Sciences, University of California. MRID 44038201. A LD 50 of >11 ȝ g/bee was classified as practically non -toxic. Although the test product was given (Aquathol K, 28.6% ae); it is not clear if any additional adjustments are needed to present the data as

ae. A new acute contact toxicity study is needed based on the new guideline methods.

### 35 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

Special study OECD 213 Honey bee adult acute oral toxicity (None) (Not applicable) No An acute oral toxicity study with the adult honey bee is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special Study (NG) Honey bee adult chronic toxicity (None) (Not applicable) No A chronic oral toxicity study with the adult honey bee is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special study OECD 237 Honey bee larvae acute oral toxicity (None) (Not applicable) No An acute oral toxicity study with the honey bee larvae is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special Study (NG) Honey bee larvae chronic toxicity (None) (Not applicable) No A repeat dose toxicity study with honey bee larvae is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special Study (NG) Field trial of residues in pollen and
nectar (None) (Not applicable) No A field trial measuring the residues of Endothall in pollen and nectar is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special Study OECD 75 Semi

- field testing for pollinators (None) (Not applicable) Tiered Approach Results of the Tier I studies could trigger the higher Tier studies (Tier II and III), see below; testing should be completed using the salts, as that is what the bees will be exposed to.

850.3040 Field testing for pollinators (None) (Not applicable) Tiered approach Results of the Tier I studies could trigger the higher Tier studies (Tier II and III), see below; testing should be completed using the salts, as that is what the bees will be exposed to.

850.4100 Seedling Emergence 42396405 Acceptable Yes None 44392803 Acceptable

850.4150 Vegetative Vigor 42396405 Acceptable Yes None 44392803 Acceptable

### 36 Table 23. Submitted Terrestrial Ecological Effects Data for the Disodium Salt of Endothall

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

870.3800 Mammalian 2- generation Reproduction 43152101 Acceptable Yes None 43629301 Acceptable

Table 24. Submitted Terrestrial Ecological Effects Data for the Mono (N,N-dimethylalkylamine) Salt of Endothall

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.2100 Avian oral toxicity 00035237 Acceptable

No Yes

– a passerine species is needed to fulfill guideline requirements. Tier 1 EECs from past assessments ranged from
approx. 23.52- 1347.45 ppm ae

, and the acute LD 50 was = 91 mg ae/kg -bw and the sub-acute LC 50 was >1170 mg ae/kg -diet. The passerine LD 50 would have to be at least 4 -150 times greater than the other avian species to no longer result in an acute listed species LOC exceedance of 0.1. Data are needed for passerine species using the mono (N,N

dimethylalkylamine) salt

, especially given the uncertainty surrounding the dose of one of the available acute oral studies for the mono salt (emesis in all treatment levels). Data are needed for the dimethylalkylamine salt and either the dipotassium salt or the free acid. 42359601 Supplemental

850.2200 Avian dietary toxicity 43167901 Acceptable Yes None 43167902 Acceptable

### 37 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

850.2300 Avian reproduction 47861102 Acceptable

No The mallard study (MRID 47861101) was classified as supplemental (not upgradable) because a definitive NOAEC could not be established (treatment

- related effects were observed in the lowest test concentration). Toxicity d ata

are needed for the mallard duck for the dimethylalkylamine salt ; but a study for bobwhite quail is needed for either the free acid or the dipotassium salt. 47861101 Supplemental

870.1100 Mammalian acute oral 42774001 Acceptable Yes None

870.1300 Mammalian
acute inhalation 42560901 Acceptable Yes None

870.3800 Mammalian 2- generation Reproduction (None) (Not applicable) Yes None with the mono (N,Ndimethylalkylamine) s alt of endothall ; the test substance is only the disodiu m salt of endothall; MRID #’ s 43152101 and 43629301 (see above).

850.3020 Honey bee adult acute contact toxicity 44038201 Acceptable No Based on classification in paper by Atkins, E.L. Division of Agricultural Sciences, University of California. MRID 44038201. A LD 50 of >11 ȝ g/bee was classified as practically non -toxic. Although the test product was given (Hydrothol 191 23.4% ae); it is not clear if any additional adjustments are needed to present the data as ae. A new acute contact toxicity study is needed based on the new guideline methods.

Special study OECD 213 Honey bee adult acute oral toxicity (None) (Not applicable) No An acute oral toxicity study with the adult honey bee is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special Study (NG) Honey bee adult chronic toxicity (None) (Not applicable) No A chronic oral toxicity study with the adult honey bee is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

### 38 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Sufficient for risk assessment? Current Additional Data Need

Special study OECD 237 Honey bee larvae acute oral toxicity (None) (Not applicable) No An acute oral toxicity study with the honey bee larvae is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special Study (NG) Honey bee larvae chronic toxicity (None) (Not applicable) No A repeat dose toxicity study with honey bee larvae is needed; testing should be completed using the salts, as that is what the bees will be exposed to.

Special Study (NG) Field trial of residues in pollen and
nectar (None) (Not applicable) No A field trial measuring the residues of Endothall in pollen and nectar is needed; testing should be completed using the salts, as that is what the bees will be exposed
to.

Special Study OECD 75 Semi

- field testing for pollinators (None) (Not applicable) Tiered Approach Results of the Tier I studies could trigger the higher Tier studies (Tier II and III), see below; testing should be completed using the salts, as that is what the bees will be exposed to.

850.3040 Field testing for pollinators (None) (Not applicable) Tiered approach Results of the Tier I studies could trigger the higher Tier studies (Tier II and III), see below; testing should be completed using the salts, as that is what the bees will be exposed to.

850.4100 Seedling Emergence 43870401 Acceptable Yes None

850.4150 Vegetative Vigor 43870401 Acceptable Yes None



### Data Gaps Acid and/or Dipotassium salt

x OCSPP 850.1300: Freshwater invertebrate life cycle

x OCSPP 850.1350: Saltwater invertebrate life cycle

x OCSPP 850.1400: Saltwater fish early-life stage (sheepshead minnow)

o or OCSPP 850.1075 Freshwater fish acute toxicity with fathead minnow ( acid only) for calculation of an ACR

x OCSPP 850.2100: Avian acute oral toxicity with passerine species

x OCSPP 850.2300: Avian reproduction

– bobwhite quail

### 39 Dipotassium salt (only)

x OCSPP 850.3020: Honeybee acute contact toxicity study

x OECD TG 213 and Non-guideline special studies: Honey bee adult acute and chronic oral toxicity studies

x OECD TG 237 and Non-guideline special studies: Honeybee larval acute and chronic oral toxicity studies

x Non-guideline special studies: Field trial measuring residues of endothall in pollen and
nectar

x Special study OECD TG 75 and OSCPP 850.3040: Semi-field testing for pollinators and Field testing for pollinators (both studies are conditionally required pending the results of the Tier I

– laboratory based studies listed above; if needed protocols for each study must be submitted for review prior to study initiation).
Mono (N,N-dimethylalkylamine) salt

x OCSPP 850.1350: Saltwater invertebrate life cycle

x OCSPP 850.2100: Avian acute oral toxicity with passerine species

x OCSPP 850.2300: Avian reproduction

– mallard duck

x OCSPP 850.3020: Honeybee acute contact toxicity study

x OECD TG 213 and Non-guideline special studies: Honey bee adult acute and chronic oral toxicity studies

x OECD TG 237 and Non-guideline special studies: Honeybee larval acute and chronic oral toxicity studies

x Non-guideline special studies: Field trial measuring residues of endothall in pollen and
nectar

x Special study OECD TG 75 and OSCPP 850.3040: Semi-field testing for pollinators and Field testing for pollinators (both studies are conditionally required pending the results of the Tier I

– laboratory based studies listed above; if needed protocols for each study must be submitted for review prior to study initiation).
Honeybee Toxicity: Although endothall is categorized as practically non-toxic to adult honeybees on contact exposure basis, and by extension, to other beneficial terrestrial invertebrates on an acute exposure basis, there is considerable uncertainty regarding the potential effects of the compound on honeybee larval development and survival as well as potential for chronic effects. Therefore, additional data on pollinators is needed to fully characterize the risk associated with endothall use to all developmental stages of honeybees, as sensitivity may vary according to life-stage and length of exposure (adult vs. larval and acute vs. chronic, respectively). Endothall is an herbicide so exposure via pollen and nectar is possible; and therefore, residues of pollen and nectar of crops are an additional set of data that is needed. Open literature data can be used to help better characterize some uncertainties regarding potential effects to bees and other non-target terrestrial invertebrates. In addition, higher tier effects toxicity tests ( i.e., semi-field and/or field studies

– Tier II and Tier III, respectively) may also be needed, based on the results of the larval and chronic adult toxicity studies. Higher tier studies are recommended if the ratio of the EEC and larval or adult bee acute LD 50 

### > 0.4 or the ratio of the EEC and the chronic NOAEC> 1 . Incident data and/or compelling open literature studies can also be used to support the need for higher tier studies. Should the screening level risk assessment identify that there are risk concerns to bees, mitigation measures may need to be considered or the registrant may need to conduct Tier II or Tier III effects studies ( e.g. OECD Guideline 75 and/or

### 40 850.3040 guideline studies) that reduce uncertainty by characterizing endothall ’s effects at the whole-colony level 1



### .

Study Title: Honey bee Adult Acute Oral Toxicity Guideline Number: Special Study

– OECD 213; Test Substance: Endothall

– Dipotassium Salt and Mono (N,N-dimethylalkylamine) Salt Rationale for Requiring the Data No data are available with which to assess the toxicity of endothall to honey bees on an acute oral exposure basis. Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. With eusocial bees, pesticide residue s may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the hive . Therefore, potential acute effects to adult honey bees and other insect pollinators from oral exposure to some pesticides could exist . Currently avail able toxicity studies do not address possible effects of oral exposure on adult terrestrial insect survival

. Because of the potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it is importa nt to determine the acute oral toxicity of this compound to adult honey bees and other insect pollinators.
The Office of Pesticide Programs has made available a guidance regarding ecological testing for bees using the honey bee as a surrogate test species. The guidances discusses Tier 1 laboratory- based acute oral toxicity studies of individual adult bees as a critical component of the screening -level risk assessment process for examining potential adverse effects fr om specific routes of exposure. The guidance can be found at: http://www2.epa.gov/pollinator -protection/pollinator-risk-assessment-guidance

. Additional guidance on the honey bee oral toxicity test design can be found in OECD Test Guideline 213 ( http://www.oecdilibrary.org/docserver/download/9721301e.pdf?expires=1423074617&id=id&accname=guest&checksum=2F 0764FCB4DCF01D32382952A2E995C3 ) Practical Utility of the Data How will the data be used? The Tier 1 acute oral toxicity data on adult honey bees serve as a foundation for the screening-level assessment of potential risk non

- target organisms such as federally listed threatened or endangered and nonlisted terrestrial invertebrate insects, including pollinators, from acute oral exposures to pesticid es. The data will be used to reduce uncertainties associated with the risk assessment for terrestrial invertebrates and will improve EPA’s understanding of the potential direct and indirect ef fects on a broad range of taxa. This study will also provide inf ormation with which to compare whether oral toxicity estimates differ from contact toxicity estimates obtained from other Tier 1 studies. If acute oral effects data for adult honey bees are not available, risks to terrestrial insects from acute oral exposu re will be assumed. Risk estimates based on these data will be considered along with other lines of evidence to determine whether higher

- tier studies are needed at the whole colony level.
How could the data impact the Agency’s future decision -making? The data will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non

- target species or is likely to adversely affect listed threatened or endangered species and/or modify their designated critical habitat. Without these data, EPA may need to presume risk

, which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

1 http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance

.

### 41 Study Title: Honey Bee Acute Larvae Oral Toxicity Study; Guideline Number: Special Study

– OECD 237; Test Substance: Endothall

– Dipotassium Salt and Mono (N,N-dimethylalkylamine) Salt Rationale for Requiring the Data No data have been submitted on the toxicity of endothall to honey bee larvae. Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings

. With eusocial bees, pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the hive where developing larvae and pupae may be exposed

. Therefore, potential adverse effects to developing bees could result from exposure to pesticide residues . Available toxicity studies do not address possible effects on brood (larvae and pupae) survival/development

. Because of the potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it is important to determine the acute
tox icity of this compound to bee brood.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for bees using the honey bee as a surrogate test species. The guidances discusses Tier 1 laboratory- based acute toxicity studies of individual honey bee larvae as a critical component of the screening- level risk assessment process for examining potential risks from specific routes of exposure. The guidance be found at: http://www2.epa.gov/pollinator -protection/pollinator-risk-assessment-guidance

. Additional guidance on larval honey bee toxicity test design can be found in OECD Test Guideline 237 ( http://www.oecdilibrary.org/docserver/download/9713171e.pdf?expires=1422485600&id=id&accname=guest&checksum=D 8E07C2B1DF77BF096C3B29F55BF86A7 ). In some cases, information pertaining to acute toxicity to honey bee larvae may be obtained with the chronic honey bee larval test thereby negating the need for separate acute and chronic larval toxicity tests. Practical Utility of the Data How will the data be used? The Tier 1 acute toxicity data on honey bee larvae serve as a foundation for the screening- level assessment of potential risk to non -target organisms including federally listed threatened or endangered and non-listed terrestrial invertebrates, including pollinators, and/or modify their designated critical habitat from acute exposures to pesticides. The data will be used to reduce uncertainties associated with t he risk assessment for terrestrial invertebrates and will improve EPA’s understanding of the potential effects on terrestrial species and whether there is a differential sensitivity of larval bees relative to adult bees. If acute effects data for larvae a re not available, risks to terrestrial insects from acute exposure will be assumed. Risk estimates based on these data will be considered along with other lines of evidence to determine whether higher

- tier studies are needed at the whole colony level.

Ho w could the data impact the Agency’s future decision -making? The data will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non -target specie s or is likely to adversely affect listed threatened or endangered species and/or modify their designated critical habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

### 42 Study Title: Honey Bee Adult Chronic Oral Toxicity Guideline Number: Special Study

– Non-guideline; Test Substance: Endothall

– Dipotassium Salt and Mono (N,N-dimethylalkylamine) Salt Rationale for Requiring the Data No data have been submitted on the chronic toxicity of endothall to adult honey bees. A study is needed to determine the chronic toxicity of the compound to adult honey bees, including mortality and sublethal effects. Terrestrial inve rtebrates are likely to be impacted if exposed to pesticides in various use settings. With eusocial bees, p esticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the hive . Therefore, potential chro nic effects to adult honey bees and other pollinators from oral exposure to some pesticides could exist . Currently available toxicity studies do not address possible lethal and sublethal effects of chronic oral exposure on adult terrestrial invertebrates and will assist in determining whether the sensitivity of adult bees differs from that of earlier life stages

. Because of the potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it is important to determine the chronic oral toxicity of this compound to adult honey bees and other pollinators.

The Office of Pesticide Programs has made available a guidance regarding ecological testi ng for bees using the honey bee as a surrogate test species. The guidances discusses Tier 1 laboratory-based chronic oral toxicity studies of individual adult honey bees as a critical component of the screening- level risk assessment process for examining potential risks from specific routes of exposure . The guidance can be found at: http://www2.epa.gov/pollinator -protection/pollinator-risk-assessment-guidance . Although study design elements for the chronic 10 -day oral toxicity test with honey bees are similar to the OECD TG 213 acute oral toxicity test ( http://www.oecdilibrary.org/docserver/download/9721301e.pdf?expires=1422484908&id=id&accname=guest&checksum=C 38495D2A570AC2216CFB1F223D24AA7 ), EPA requires that the proposed protocol for this study be submitted for review and approval by EPA prior to initiating the test. Practical Utility of the Data How will the data be used? The Tier 1 chronic toxicity data on adult bees serve as a foundation for the screening-level assessment of potential risk to non -target organisms including federally listed threatened or endangered species and non

listed terrestrial invertebrates, including pollinators, from chronic oral exposures to pesticides. The data will be used to reduce uncertainties associated with the risk assessment for terrestrial invertebrates and will improve EPA’s understanding of the potential direct and indirect lethal and sublethal effects on a broad range of terrestrial species, particularly insect pollinators and to determine whether adult toxicity differs substantially from other life stages evaluated in other Tier 1 tests. If chronic oral effects data for adults are not available, risks to terrest rial insects from chronic exposure will be assumed. Risk estimates based on these data will be considered along with other lines of evidence to determine whether higher

- tier studies are needed at the whole colony level.

How could the data impact the Agen cy’s future decision -making? The data will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non

- target species or is likely to adversely affect listed threatened or endangered species and/or their designated critical habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

### 43 Study Title: Honey Bee Larvae Chronic Oral Toxicity Guideline Number: Special Study

– Non-Guideline; Test Substance: Endothall

– Dipotassium Salt and Mono (N,N-dimethylalkylamine) Salt Rationale for Requiring the Data No data have been submitted on the toxicity of endothall to honey bee larvae. Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings

. For eusocial bees, pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the hive where larvae and pupae may be exposed

. Therefore, potential effects to developing bees could result from chronic exposure to pesticide residues . Available toxicity studies do not address possible chronic effects on brood (larvae and pupae) survival

. Because of the potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it is important to determine chronic larval/pupal toxicity and whether adult emergence is adversely affected. This study will provide information on whether honey bee larvae differ in sensitivity from adult bees following chronic exposure.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for bees using the honey bee as a surrogate test species. The guidances discusses Tier 1 laboratory- based chronic toxicity studies of individual honey bee larvae as a critical component of the screening- level risk assessment process for examining potential risks from specific routes of exposure. The guidance can be found at: http://www2.epa.gov/pollinator -protection/pollinator-risk-assessment-guidance. Additional information on larval honey bee toxicity repeat exposure test design can be found in the OECD draft guidance ( http://www.oecd.org/env/ehs/testing/Draft_GD_honeybees_rep_exp_for_2nd_CR_25_November_2013.pdf

. Although study design elements for the chronic 21 -day toxicity test with honey bee larvae have been d rafted, EPA requires that the proposed protocol for this study be submitted for review and approval by EPA prior to initiating the test. Practical Utility of the Data How will the data be used? The Tier 1 chronic toxicity d ata on bee larvae serve as a foundation for the screening- level assessment of potential risk to non -target organisms including federally listed threatened or endangered and non-listed terrestrial invertebrates, including insect pollinators, from chronic ex posures to pesticides. These data will be used to reduce uncertainties associated with the risk assessment for terrestrial invertebrates and will improve EPA’s understanding of the potential direct and indirect lethal and sublethal effects on a broad rang e of terrestrial species, particularly insect pollinators. These data will also assist in determining whether early life stages of the bee differ in their sensitivity to pesticides relative to adults

. If chronic effects data for larvae are not available, risks to terrestrial insects from chronic exposure will be assumed. Risk estimates based on these data will be considered along with other lines of evidence to determine whether higher

- tier studies are needed at the whole colony level.

How could the dat a impact the Agency’s future decision -making? The data will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non -target species or is likely to adversely affect listed threatened or endangered species and/or modify their designated critical habitat

. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

### 44 Study Title: Residues in Pollen and Nectar Guideline Number: Special Study

– Non-guideline; Test Substance: Endothall

– Dipotassium Salt and Mono (N,N-dimethylalkylamine) Salt Rationale for Requiring the Data Measurements of residues in the pollen/nectar are needed based upon lower-tiered tests and/or other lines of evidence, and the need for a refined pollinator risk assessment. Terrestrial invertebrates are likely to be impacted if exposed to pesticides resid ues in various use settings. Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to hive all life stages may be exposed. For some pesticides, the quantification of pollinator -relevant residues in tr eated flowering plants is needed, since pollinators will be exposed to residues from either current or prior season applications (due to the potential for residues to accumulate in plants and trees) . Residues in edible/transportable-to- hive parts of treated trees and plants, including (where appropriate), but not limited to, guttation water, sap/resins, whole plant tissue ( e.g., leaves, stems), as well as blooming, pollen- shedding, and nectar producing parts ( i.e.
, flowers and, if present, extra -floral nectaries) of plants may inform the potential for risk. Studies should be designed to provide residue data for crops and application methods of concern.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for bees using the honey bee as a surrogate. This can be found at: http://www2.epa.gov/pollinator- protection/pollinatorrisk -assessment-guidance. Since residue studies are inte nded to provide exposure data in multiple matrices and under specific application conditions, EPA requires that the protocol is submitted for review and approval by EPA prior to initiation of the study. Practical Utility of the Data How will the data be used? Measured residue data will be used to refine conservative estimates of pesticide exposure and reduce uncertainties associated with the Tier 1 exposure assessment by providing direct measurements of pesticide concentrations resulting from actual use settings. Measured residues may provide a more realistic understanding of exposure through contact or ingestion with which to calculate risk quotients for individual bees as well as to characterize exposure to the colony. If measured residue data are not available, risk estimates for terrestrial insects will be based on model generated or default values used to support the screening -level assessment.

How could the data impact the Agency’s future decision -making? The data will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non

- target species or is likely to adversely affect federally listed threatened or endangered species or their designated critical habitat. Without these data, EPA will have to rely on conservative estimates of exposure which may limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions.

### 45 Study Title: Semi-field Testing for Pollinators (tunnel or colony feeding studies) Guideline Number: Special Study

– Non-guideline, OECD 75; Test Substance: Endothall

– Dipotassium Salt and Mono (N,N-dimethylalkylamine) Salt Rationale for Requiring the Data Should the screening level risk assessment identify that there are risk concerns to bees, mitigation measures may need to be considered or the registrant may need to conduct Tier 2 or Tier 3 effects studies. For eusocial bees, pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the hive and may adversely affect developing brood (egg, larvae, and pupae) and adult bees. Tier 2 feeding studies are condi tional on the outcome of the screening- level assessment where acute and/or chronic risk levels of concern have been exceeded for terrestrial invertebrates based on Tier 1 studies of individual bees. Feeding studies utilize free foraging bee colonies that a re “dosed” with specific quantities of test material and represent a means of ensuring exposure to the test material through spiked pollen and/or sugar solutions fed to the colony while still allowing the bees to forage freely . Since bee colonies are not c onfined to enclosures, colonies can be exposed for longer duration periods without subjecting the bees to stress that typically results from Tier 2 tunnel studies. Available toxicity studies of individual bees (Tier 1) conducted to support screening -level assessments do not address possible effects and/or exposure to pesticide residues at the colony -level. It is therefore important to determine whether bee colonies may be negatively affected where bees are free foraging and have the option to collect/consume alternative forage items beyond the spiked food. Since multiple dose levels can be more readily tested, feeding studies can help to define dose

- response relationships at the whole colony level. The Office of Pesticide Programs has made available a guid ance regarding ecological testing for bees using the honey bee as a surrogate. This guidance describes the tiered testing process and can be found at: http://www2 .epa.gov/pollinator-protection/pollinator-risk-assessment-guidance

. Additional information on honey
bee colony feeding studies can be found in the EPPO Guidance 170 ( www.nationalbeeunit.com/downloadDocument.cfm?id=191 ). Formal guidelines for semi- field tests do not yet exist; however, information that can help guide the development of either a semi

- field tunnel test protocol can be found at OECD 75 ( http://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=env/jm/mono(2007)22&doclanguage=en)

. Although study design elements for the feeding study are available through the EPPO Guidance 170 and OECD 75, EPA requires that the proposed protocol for this study be submitted for review and approval by EPA prior to initiating the test. Practical Utility of the Data How will the data be used? Tier 2 colony feeding data will be used to assess potential risk to non

- target organisms including listed and

non -listed terrestrial social invertebrate species. The colony feeding study is designed to represent potential field -level exposure and account f or hive dynamics using longer duration exposure periods than are possible in Tier 2 tunnel studies. This study will be used to determine whether potential adverse effects to insect pollinators at the whole colony level when bees are able to forage naturally beyond the spiked food. Results from the feeding study will help to refine the screening

- level risk assessment for beneficial terrestrial invertebrates that were based on Tier 1 studies on individual bees. Since feeding studies can help to define a dose

- response relationship at the colony level, the studies can provide a means of determining exposure thresholds below which the likelihood of adverse effects on colonies may be low.
How could the data impact the Agency’s future decision -making? The Tier 2 colony-level data will be used to refine screening- level risk estimates derived using Tier 1 laboratory -based data on individual bees. The Tier 2 data will help to inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non

- target species or is likely to adversely affect federally listed threatened or endangered species or their designated critical habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in significant use restrictions.

### 46 Study Title: Field Testing for Pollinators Guideline Number: Special Study

– 850.3040, 850.2500 (design elements); Test Substance: Endothall

– Dipotassium Salt and Mono (N,N-dimethylalkylamine) Salt Rationale for Requiring the Data Should the screening level risk assessment identify that there are risk concerns to bees, mitigation measures may need to be considered or the registrant may need to conduct Tier 2 or Tier 3 effects studies. Tier 3 studies are conditional on the outcome of the screening

- level assessment (Tier 1) where acute and/or chronic risk levels of concern have been exceeded for terrestrial invertebrates and where Tier 2 studies either under semifield tunnel conditions and/or feeding studies have indicated potential adverse effects at the colony level. Available toxicity studies from lower

- tier studies do not address possible effects and/or exposure to pesticide residues at the colony -level under actual pesticide use conditions and where specific uncertainties regarding the likelihood of exposure and/or effects remain . Full- field studies also provide an opportunity to measure residues in pollen and nectar as well as various matrices (beebread, honey, wax) within the colony to obtain a more realistic understanding of exposure.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for bees using the honey bee as a surrogate. This guidance describes the tiered testing process and can be found at: http://www2.epa.gov/pollinator -protection/pollinator-risk-assessment-guidance. Additional information on honey bee colony studies under full -field conditions can be found in the OCSPP 850.3040 ( http://www.regulations.gov/#!documentDetail;D=EPA -HQ-OPPT-2009-0154-0018 ). Useful guidance is also available through OCSPP 850. 2500 (Field Testing of Terrestrial Wildlife; http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series850.htm ) Although design elements for the full -field colony- level study are available through the 850.3040 and 850.2500, EPA requires that the proposed protocol for this study be submitted for review and approval by EPA prior to initiating the test; the protocol should attempt to address specific uncertainties identified in lower-tier studies. Practical Utility of the Data How will the data be used? Tier 3 colony -level data will be used to further characterize potential risk to non- target organisms including listed and non -listed terrestrial social invertebrate species and to refine screening- level risk estimates that were based on individual bee resp onses. The semi-field test is a controlled study that is designed to represent potential field

- level exposure under relatively controlled conditions and account for hive dynamics, which are not achievable from lower -tier pollinator studies. This study will be used to determine whether adverse effects to insect pollinators at the whole colony level, may result for the use of pesticides and will help to refine the screening -level risk estimates for beneficial terrestrial invertebrates. This study will also be used to determine whether more refined (Tier 3) studies are needed to characterize risk.

How could the data impact the Agency’s future decision -making? The data will inform the determination required under FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to non

- target species or is likely to adversely affect federally listed threatened or endangered species or their designated critical habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in significant use restrictions.

### 47 

## 10. References

Keller, A. E., Dutton, R. J., Bitton, G., and Crisman, T. L. 1988. Chronic Toxicity of Hydrothol 191 to Ceriodaphnia dubia at 25 and 15 Degrees C. Bull.Environ.Contam.Toxicol. 41[2], 233 240. E012941. MRID 49660201.

United States Environmental Protection Agency (USEPA). 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs . U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. Available
at http://www.epa.gov/espp/consultation/ecorisk-overview.pdf

USEPA. 2004. Memorandum “Environmental Fate and Ecological Risk Assessment of Endothall (PC Code 038901, 038903, 038904, 038905, DP Barcode D236807, D240095, D263581, D288190, D287268, and D307700) ” to Registration Division. Dated September 30, 2004. Office of Prevention, Pesticides, and Toxic Substances, U.S. Environmental Protection Agency, Washington, D.C.

USEPA. 2005 . Memorandum “Environmental Fate and Ecological Risk Assessment of Endothall

– Revised (PC Code 038901, 038903, 038904, 038905, DP Barcode D315240) ” to Registration Division. Dated April 22, 2005. Office of Prevention, Pesticides, and Toxic Substances, U.S. Environmental Protection Agency, Washington, D.C.

USEPA. 2005 . Memorandum “Environmental Fate and Effects Division Error-only corrections of the Endothall RED (PC Code 038901, 038904, 038905, DP Barcode D316102) ” to Registration Division. Dated April 22, 2005. Office of Prevention, Pesticides, and Toxic Substances, U.S. Environmental Protection Agency, Washington, D.C.

USEPA. 2009. Memorandum “ Ecological Risk Assessment Addressing the Proposed Registration of Endothall Applied as Irrigation Water for New Use Crops under IR-4 (PC Code 038901, 038904, 038905, DP Barcode D356316) ” to Registration Division. Dated October 29, 2009. Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C.

USEPA. 2013. Memorandum “ Endothall - Dipotassium salt: Ecological Risk Assessment for Proposed New Formulation and New Use on Apple trees (PC Code 038904, DP Barcode D403244) ” to Registration Division. Dated March 19, 2013. Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C.

USEPA. 2014. Memorandum “ Endothall - Dipotassium salt: Addendum to the “Ecological Risk Assessment for Proposed New Formulation and New Use on Apple trees, DP 403244” (PC Code 038904, DP Barcode D417414) ” to Registration Division. Dated February 4, 2014. Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C.

USEPA. 2007 a . ECOTOXicology Database. Office of Research and Development National Health and Environmental Effects Research Laboratory’s (NHEERL’s) Mid -Continent Ecology Division (MED). http://cfpub.epa.gov/ecotox/

### 48 USEPA. 2014 a . Guidance for Assessing Pesticide Risks to Bees. U.S. Environmental Protection Agency, Office of Pesticide Programs; Health Canada Pest Management Regulatory Agency; and California Department of Pesticide Regulation. Jun. 23, 2014. Available at http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance

.



## a. Submitted Environmental Fate Studies

MRID: 124624 Oregon State Univ. (1963). Progress Report on the Soil Behavior of Endothal. (Unpublished study received Dec 1, 1970 under 1F1105; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:094511-D).

MRID: 124626 Oregon State Univ. (19??). Preliminary Investigations of the Behavior of Endothal in Water. (Unpublished study received Dec 1, 1970 under 1F1105; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:094511-G)

MRID: 147122 Carlson, R. (1985). The Hydrolysis of Endothall in Water: Project No. WT-3-85. Unpublished study prepared by Pennwalt Corp. 18 p.

MRID: 44578401 Mao, J. (1997). Endothall Amine Salt- Determination of pH Dependent Hydrolysis: Lab Project Number: 12442.0396.6209.715: KP-96-01: 96-6-6537. Unpublished study prepared by Springborn Laboratories, Inc. 79 p.

MRID: 147123 Pennwalt Corp. (1985). Photodegradation of Endothall in Water. Unpublished study. 9 p.

MRID: 42289205 Saxena, A.; Marsh, S.; Koebel, D. (1991). Photodegradation of carbon-14 Endothall in a Buffered Aqueous Solution Under Artificial Sunlight: Final Report: Lab Project Number: SC910024: BR-91-25. Unpublished study prepared by Battelle. 55 p.

MRID: 42289206 Zwick, T.; Kazee, B.; Marsh, S. (1990). Photodegradation of (carbon-14) Endothall in Water Under Artificial Light: Final Report: Lab Project Number: SC890059. Unpublished study prepared by Battelle. 92 p.

MRID: 42641201 Zwick, T.; Kazee, B.; Marsh, S. (1992). Photodegradation of (carbon-14) Endothall in Water under Artificial Light: Amended Final Report: Lab Project Number: SC890059: N0758-4400. Unpublished study prepared by Battelle. 92 p.

MRID: 113974 Oregon State Univ. (1962). Progress Report on the Endothal Project. Progress rept., no. 2. (Unpublished study received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-B).

MRID: 147124 Pennwalt Corp. (1985). Photodegradation of Endothall on Soil. Unpublished study. 10 p.

MRID: 42289207 Saxena, A.; Zwick, T.; Marsh, S.; et al. (1991). Photodegradation of (carbon-14) Endothall on Sandy Loam Soil Under Artificial Light: Final Report: Lab Project Number: SC890060: BR-90-02. Unpublished study prepared by Battelle. 67 p.

### 49 MRID: 42641202 Saxena, A.; Zwick, T.; Marsh, S.; et al. (1992). Photodegradation of (carbon-14) Endothall on Sandy Loam under Artificial Light: Amended Final Report: Lab Project Number: SC890060: BR-90-02. Unpublished study prepared by Battelle. 67 p.

MRID: 113974 Oregon State Univ. (1962). Progress Report on the Endothal Project. Progress rept., no. 2. (Unpublished study received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-B).

MRID: 113979 Temby, F. (1963). Biological Breakdown of Endothal Compounds. (Unpublished study received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL: 121844-N).

MRID: 124624 Oregon State Univ. (1963). Progress Report on the Soil Behavior of Endothal. (Unpublished study received Dec 1, 1970 under 1F1105; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:094511-D).

MRID: 124625 Freed, V. (1963). Progress Report on the Study of the Degradation Products of Endothal in Soil. (Unpublished study received Dec 1, 1970 under 1F1105; prepared by Oregon State Univ., submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL: 094511-F)

MRID: 162920 Dykeman, R. (1986). Aerobic/Anaerobic Soil Metabolism of Endothall: Final Report: Project No. WT-86-C-1. Unpublished study prepared by Agchem Div., Pennwalt Corp. 185 p.

MRID: 44949401 Atkins, R.; Peel, D.; Marsh, D. (1999). Aerobic Soil Metabolism of (carbon-14) Endothall: Lab Project Number: 1134: 2045: KP-97-24. Unpublished study prepared by PTRL East, Inc. 167 p.

MRID: 162920 Dykeman, R. (1986). Aerobic/Anaerobic Soil Metabolism of Endothall: Final Report: Project No. WT-86-C-1. Unpublished study prepared by Agchem Div., Pennwalt Corp. 185 p.

MRID: 79977 Sikka, H.C.; Saxena, J. (1973). Metabolism of endothall by aquatic microorganisms. Journal of Agricultural and Food Chemistry 21 (3):402-406. (Also In unpublished submission received Feb 1, 1975 under 4581-EX-21; submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:094575-G).

MRID: 113974 Oregon State Univ. (1962). Progress Report on the Endothal Project. Progress rept., no. 2. (Unpublished study received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-B).

MRID: 113975 Montgomery, M. (1962). Letter sent to O. Keckemet dated Oct 16, 1962 Endothal in soil. Progress rept., no. 3. (Unpublished study received Jul 8, 1965 under 4581-232; prepared by Oregon State Univ., Dept. of Agricultural Chemistry, Agricultural Experiment Station, submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-C).

MRID: 113977 Comes, R.; Bohmont, D.; Alley, H. (1961). Movement and persistence of endothal ... as influenced by soil texture, temperature, and moisture levels. Journal of the A.S.S.B.T. XI

### 50 (4):287-293. (Also In unpublished submission received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-L).

MRID: 113978 Agchem (19??). Movement and Persistence of Endothal under Controlled Conditions. (Unpublished study received Jul 8, 1965 under 4581- 232; CDL:121844-M).

MRID: 113980 Temby, F. (1963). Soil Movement Studies with Endothal Compounds. (Unpublished study received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL: 121844-O).

MRID: 113981 Temby, F. (1963). Soil Adsorption Studies- Endothal Compounds. (Unpublished study received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-P).

MRID: 113986 Freed, V.; Montgomery, M.; Fang, S. (1958). The Absorption and Translocation of C14 Labelled Endothal in Red Beets and Spinach. (Unpublished study received Sep 8, 1958 under unknown admin. no.; prepared by Pennsylvania Salt Mfg. Co. of Washington, submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL: 124421-A).

MRID: 113987 Agchem (1970). The Results of Tests on the Amount of Residue Remaining Including a Description of the Analytical Method Used: Endothall. (Compilation; unpublished study received Jun 27, 1971 under unknown admin. no.; CDL:124882-A).

MRID: 114521 Freed, V.; Montgomery, M. (1963). Progress Report on the Study of the Degradation Products of Endothal in Soil. (Unpublished study received Mar 15, 1966 under 4581- 139; prepared by Oregon State Univ., Agricultural Experiment Station, Dept. of Agricultural Chemistry, submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:007441-X).

MRID: 114523 Agchem (1961) Chemical Study: Endothall. (Compilation; unpublished study received Mar 15, 1966 under 4581-139; CDL: 007441-AB)

MRID: 124624 Oregon State Univ. (1963) Progress Report on the Soil Behavior of Endothall. (Unpublished study received Dec 1, 1970 under 1F1105; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:094511-D)

MRID: 124627 Horowitz, M. (1966). Breakdown of Endothal in soil. Weed Research 6(2):168- 171. (Also In unpublished submission received Dec 1, 1970 under 1F1105; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:094511-H).

MRID: 156635 Dykeman, R. (1985). Adsorption/Desorption of Endothall on Soils by Batch Equilibrium Method: Final Report: Project No. WT-7-85. Unpublished study prepared by Pennwalt Corporation, Agchem Division. 71 p.

MRID: 41616404 Vigon, B. (1989). Adsorption/Desorption of 14C (Carbon 14) ring (2,3) Endothall on Soils by the Batch Equilibrium Method: Lab Project Number: NO962/6200. Unpublished study prepared by Battelle. 68 p.

### 51 MRID: 38645 Van Horn, S.L. (1975). Dissipation of the Herbicides Endothall, Diquat, and a 1:1 Mixture in Water, Sediment, and Egeria densa . Master's thesis, Virginia Polytechnic Institute and State Univ. (Unpublished study received Jun 13, 1975 under 5E1648; submitted by Chevron Chemical Co., Richmond, Calif.; CDL:095428-AA).

MRID: 113927 Agchem (1966). Description of Analytical Methods and Results of Analyses for Dimethylcocoamine Endothall (Accelerate) in Cotton-seed. (Compilation; unpublished study received Feb 14, 1966 under 4581-284; CDL:007456-A).

MRID: 113974 Oregon State Univ. (1962). Progress Report on the Endothal Project. Progress rept., no. 2. (Unpublished study received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-B).

MRID: 118549 Amchem Products, Inc. (1971). Fenac Residue Data- Total Water Treatment. (Compilation; unpublished study received Jul 7, 1972 under 2F1213; CDL:091039-T).

MRID: 162921 Jacobson, S. (1986). Terrestrial Field Dissipation Studies for Endothall (Herbicide 273 and Des-I-Cate Harvest Aid Formulations): Final Report: Project WT-1-85 and WT-2-85. Unpublished study prepared by Agchem Div., Pennwalt Corp. 125 p.

MRID: 38645 Van Horn, S.L. (1975). Dissipation of the Herbicides Endothall, Diquat, and a 1:1 Mixture in Water, Sediment, and Egeria densa . Master's thesis, Virginia Polytechnic Institute and State Univ. (Unpublished study received Jun 13, 1975 under 5E1648; submitted by Chevron Chemical Co., Richmond, Calif.; CDL:095428-AA).

MRID: 84382 Seaman, D.E.; Berkenkotter, P.; Chen, T.M.; et al. (1966). Persistence of Residues and Fates of Herbicides in Rice Fields and in Rice-field Effluents: Progress rept. WRC Project No. W 3 02 67. For the period Mar 1, 1965 to Jan 31, 1966. (Unpublished study received Oct 8, 1981 under 476-2107; prepared by Univ. of California--Davis, Dept. of Botany, submitted by Stauffer Chemical Co., Richmond, Calif.; CDL:246011-M)

MRID: 113982 Hiltibran, R. (19??). Duration of toxicity of endothal in water. Source unknown. (Also In unpublished submission received Jul 8, 1965 under 4581-232; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:121844-Q).

MRID: 113987 Agchem. (1970). The Results of Tests on the Amount of Residue Remaining Including a Description of the Analytical Method Used: Endothall. (Compilation; unpublished study received Jun 27, 1971 under unknown admin. no.; CDL:124882-A).

MRID: 114554 3M Co. (1974). Residue Studies and Methods: System E. (Unpublished study received Dec 19, 1975 under 6H5112; CDL:225291-J).

MRID: 116739 Chevron Chemical Co. (1977). Residue Chemistry Data and Data Reference List to Support Label Amendment for Diquat Water Weed Killer. (Compilation; unpublished study received Aug 22, 1977 under 239-1663; CDL:231427-A).

MRID: 118549 Amchem Products, Inc. (1971). Fenac Residue Data--Total Water Treatment. (Compilation; unpublished study received Jul 7, 1972 under 2F1213; CDL:091039-T).

### 52 MRID: 44820101 Keckemet, O.; Sharp, J. (1999). Historical Aquatic Residue and Dissipation Data for Endothall Aquatic Products Aquathol K Aquatic Herbicide and Hydrothol 191 Aquatic Algicide and Herbicide: Lab Project Number: KP-99-02: WT-86-C-11. Unpublished study prepared by Elf Atochem. 316 p. {OPPTS 860.1400}

MRID: 44820103 Biever, R. (1998). Hydrothol 191: An Aquatic Dissipation Study for Aquatic Non-Crop Uses: Final Report: Lab Project Number: KP-96-14: 98-1-7215: 12442-0896-6214-330. Unpublished study prepared by Elf Atochem and Springborn Laboratories, Inc. 164 p.

MRID: 44828801 Singh, P.; Ritter, A.; Sharp, J. et al. (1999). Aquatic Dissipation Modeling of Endothall Acid: Aquathol K Aquatic Herbicide and Hydrothol 191 Aquatic Algicide and Herbicide: Lab Project Number: ATO KP-97-16: WEI 286.01. Unpublished study prepared by Waterborne Environmental, Inc. 363 p.

MRID: 44828802 Williams, W.; Ritter, A.; Sharp, J. et al., (1999). An Evaluation of the Aquatic Dissipation of Endothall Aquatic Product: Aquathol, K Aquatic Herbicide and Hydrothol 191 Aquatic Algicide and Herbicide: Lab Project Number: ATOKP-98-32: WEI-286.06. Unpublished study prepared by Waterborne Environmental, Inc. 69 p.



## b. Submitted Ecological Toxicity Studies
Acid

MRID Citation Reference

71131 Bodden, R.M. (1979) Avian Single-dose Oral LDI50: Study No. W-910. (Unpublished study, including letter dated Jul 8, 1980 from R.M. Bodden to Obren Keckemet, received Jan 23, 1981 under 4581 - 174; prepared by Ralston Purina Co., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-B)

72455 Bodden, M.R. (1979) Avian Single-dose Oral LD50: Study No. W-910. Final rept. (Unpublished study, including letter dated Jul 8, 1980 from R.M. Bodden to Obren Keckemet, received Jan 23, 1981 under 1F1105; prepared by Ralston Purina Co., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-B)

74220 Bodden, R.M. (1979) Avian Single-dose Oral LD50. (Unpublished study received Jan 23, 1981 under 4581 -282; prepared by Ralston Purina Co., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-B)

42359701 Pedersen, C.; Helsten, B. (1992) Endothall Technical: 21-Day Acute Oral LD50 Study in Mallard Ducks: Lab Project Number: 106 -004-04. Unpublished study prepared by Bio- Life Associates, Ltd. 50 p.

92057001 Shellenberger, T. (1990) Agchem Division-Pennwalt Corp. Phase 3 Summary of MRID 00072455. Endothall Technical

-- Single Dose Oral LD50 Value to Bobwhite Quail: Project W-910. Prepared by Hazleton Laboratories America, Inc. 10 p.

92057002 Shellenberger, T. (1990) Agchem Division-Pennwalt Corp. Phase 3 Summary of MRID 00035237. Hydrothol 191 - Acute Oral LD50 Test - Bobwhite Quail: Project No. 110- 115. Prepared by Wildlife International Ltd. 11 p.

### 53 00160000 Hudson, R.; Tucker, R.; Haegele, M. (1984) Handbook of toxicity of pesticides to wildlife: Second edition. US Fish and Wildlife Service: Resource Publication 153. 91 p Ring

- necked pheasant and Mallard duck tested

35233 Fink, R. (1975) Final Report: Eight-Day Dietary LC50--Mallard Ducks: Project No. 110- 106. (Unpublished study received Oct 21, 1975 under 4581 -EX- 18; prepared by Truslow Farms, Inc., submit - ted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096340-B)

116271 Fink, R. (1975) Eight-day Dietary LC50--Mallard Ducks: Technical Endothal: Project No. 110

- 106. Final rept. (Unpublished study received Jul 9, 1975 under 1F1105; prepared by Truslow Farms, Inc., submitted by Pennwalt Corp., Tacoma, WA; CDL:094702-G)

52229 Fink, R. (1975) Final Report: Eight-Day Dietary LC50--Bobwhite Quail: Project No. 110-105 (Unpublished study received Oct 21, 1975 under 4581 -EX- 18; prepared by Truslow Farms, Inc., submit - ted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096340- A) CDL:094702-F)

116270 Fink, R. (1975) Eight-day Dietary LC50--Bobwhite Quail: Technical Endothal: Project No. 110

- 105. Final rept. (Unpublished study received Jul 9, 1975 under 1F1105; prepared by Truslow Farms, Inc., submitted by Pennwalt Corp., Tacoma, WA; CDL:094702-F).

96299 Menzie, C.M. (1964) Letter sent to H.L. Lindaberry dated Oct 15, 1964 Toxicity to mallards|. (U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, Section of Chemical and Physiological Studies; unpublished study; CDL:090719-K).

43167701 Pedersen, C.; Solatycki, A. (1994) Endothall Technical: 8-Day Acute Dietary LC 50 Study in Bobwhite Quail: Lab Project Number: 106 -011- 01. Unpublished study prepared by BioLife Associates, Ltd. 96 p.

43167702 Pedersen, C.; Solatycki, A. (1994) Endothall Technical: 8-Day Acute Dietary LC 50 Study in Mallard Ducklings: Lab Project Number: 106 -015- 02. Unpublished study prepared by Bio-Life Associates, Ltd. 94 p.

42507301 Pedersen, C.; Fletcher, D. (1992) Endothall Technical: Toxicity and Reproduction Studyin Mallard Ducks: Lab Project Number: 89 DR 37. Unpublished study prepared by BioLife Associates, Ltd. 300 p.

42507302 Pedersen, C.; Fletcher, D.; Lesar, C. (1992) Endothall Technical: Toxicity and Reproduction Study in Bobwhite Quail: Lab Project Number: 89 QR 41. Unpublished study prepared by Bio-Life Associates, Ltd. 301 p.

43558201 Rose, S.; Goin, L. (1994) Endothall Technical: 28-Day Dietary Toxicity and Reproduction Pilot Study in Mallard Ducks: Addendum: Diet Analyses: Final Report: Lab Project Number: 89 DRP 37: 33400. Unpublished study prepared by NPC, Inc.; Columbia Labs, Inc.; and Bio-Life Associates, Ltd. 49 p.

43558301 Rose, S.; Goin, L. (1994) Endothall Technical: 28-Day Dietary Toxicity and Reproduction Pilot Study in Bobwhite Quail: Addendum: Diet Analyses: Final Report: Lab Project Numbers: BLAL 89 QRP 41: 33400: 153

- 144. Unpublished study prepared by Columbia Labs, Inc.; NPC, Inc.; Bio-Life Associates, Ltd. 49 p.

43558202 Rose, S.; Goin, L. (1994) Endothall Technical: Toxicity and Reproduction Study in Mallard Ducks: Addendum: Diet Analyses: Final Report: Lab Project Number: 89 DR 37:0660: 09356. Unpublished study prepared by NPC, Inc.; Columbia Labs, Inc.; and BioLife Associates, Ltd. 47 p.

### 54 96298 Walker, C.R. (1963) Endothal derivatives as aquatic herbicides in fishery habitats. Weeds 11(3):226

- 232. (Also In unpublished submission received Feb 17, 1967 under 7F0570; submitted by Pennsalt Chemicals Corp., Bryan, Tex.; CDL:090719-J)

67174 Schreck, C.B. (1974) Aquatic Plant Control Using Herbicides in a Large Potable Water Supply Reservoir: Contract No. DACW65 -74- C- 0013. (Virginia Polytechnic Institute and State Univ., Dept. of Fisheries and Wildlife Sciences for U.S. Dept. of the Army, Corps of Engineers; unpublished study; CDL:231433-D).

69192 Bond, C.E.; Lewis, R.H.; Fryer, J.L. (1960) Toxicity of various herbicidal materials to fishes. Pages 96 -101, In Transactions of the 195 9 Seminar of Biological Problems in Water Pollution. By Robert A. Taft Engineering Center. Cincinnati, Ohio: U.S. Public Health Service. (Technical report W60-3; published study; CDL:230691-H)

71143 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate) Technical 89.5% Acid Equivalent to the Common Mummichog Fundulus heteroclitus (Linnaeus): UCES Project No. 11056-41- 12. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-P)

72465 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate) Technical 89.5% Acid Equivalent to the Common Mummichog Fundul us heteroclitus (Linnaeus): UCES Project No. 11056-41- 12. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-P).

74225 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Endothall (Acid Monohydrate) Technical 89.5% Acid Equivalent to the Common Mummichog Fundulus heteroclitus (Linnaeus): UCES Project No. 11506 -41- 12. (Unpublished study received Jan 23, 1981 under 4581 -282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-P).

114549 Economon, P. (1967) Letter sent to W. Paterson dated Nov 3, 1967 Results of bioassay on aquatic herbicide compounds|. (Minnesota, Dept. of Conservation, Div. of Game and Fish, Technical Services; unpublished study; CDL:225291-D)

114551 Whitley, J. (1968) Letter sent to W. Paterson dated Nov 18, 1968 Four-day fish toxicity tests on bluegill sunfish, black bull - head and mosquitofish. (Missouri, Dept. of Conservation, Fisheries Research Laboratory, Water Quality Investigations; unpublished study; CDL:225291-F)

114552 Bionomics, Inc. (1971) The Acute Toxicity of System E (T-350) to Bluegill ..., Rainbow Trout ..., and Largemouth Bass (Micropterus salmoides). (Unpublished study received Dec 19, 1975 under 6H5112; submitted by 3M Co., St. Paul, MN; CDL:225291-G)

116465 Paterson, W. (1969) Aquatic Herbicide System S. (Unpublished study received Mar 6, 1969 under 7182 -EX- 6; submitted by Medical Products Div., 3M Co., St. Paul, MN; CDL:127050-A) 43558302 Rose, S.; Goin, L. (1994) Endothall Technical: Toxicity and Reproduction Study in Bobwhite Quail: Addendum: Diet Analyses: Final Report: Lab Project Numbers: BLAL 89 QR 41: 0660: 09356. Unpublished study prepared by Columbia Lab, Inc.; NPC, Inc.; Bio-Life Associates, Ltd. 47 p.

### 55 118536 Hughes, J.; Davis, J. (1963) Comparative Toxicity to Bluegill Sunfish of Granular and Liquid Herbicides. (Unpublished study received Nov 26, 1963 under unknown admin. no.; prepared by Louisiana, Wildlife & Fisheries Commission, submitted by Union Carbide Agricultural Products Co., Inc., Research Triangle Park, NC; CDL:129700-A)

42327701 Bettencourt, M. (1992) Endothall Technical-Acute Toxicity to Bluegill Sunfish (Lepomis macrochirus) under Flow -through Conditions: Lab Project Number: 91-9

- 3917: 12442.0591.6121.105. Unpublished study prepared by Springborn Laboratories, Inc. 62 p.

42327702 Bettencourt, M. (1992) Endothall Technical-Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss) Under Flow -through Conditions: Lab Project Number: 91- 9- 3918: 12442.0591.6120.108. Unpublished study prepared by Springborn Laboratories, Inc. 63 p.

69192 Bond, C.E.; Lewis, R.H.; Fryer, J.L. (1960) Toxicity of various herbicidal materials to fishes. Pages 96 -101, In Transactions of the 1959 Seminar of Biological Problems in Water Pollution. By Robert A. Taft Engineering Center. Cincinnati, Ohio: U.S. Public Health Service. (Technical report W60-3; published study; CDL:230691-H)

38629 Surber, E.W.; Pickering, Q.H. (1962) Acute toxicity of Endothal, Diquat, Hyamine, Dalapo n, and Silvex to fish. Progressive Fish- Culturist (?/Oct):164- 171. (U.S. Public Health Service, Robert A. Taft Sanitary Engineering Center, published study; CDL:095428-F)

71137 Vilkas, A.G.; Hughes, J.S. (1979) The Acute Toxicity of Endothall to the Water Flea Daphnia magna Straus: UCES Project No. 11506 - 41- 09. (Unpublished study received Jan 23, 1981 under 4581 -174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-I)

42359702 McNamara, P. (1992) Endothall Technical--Acute Toxicity to Daphnids (Daphnids magna) Under Flow -through Conditions: Final Report: Lab Project Number: 91-10

- 3946: 12442.0591.6122.115. Unpublished study prepared by Springborn Labs., Inc. 64
p.

5001624 Nebeker, A.V.; Gaufin, A.R. (1964) Bioassays to determine pesticide toxicity to the amphipod crustacean, Gammarus lacustris. Pages 64

- 67, In Utah Academy of Sciences Proceedings. Vol. 41, Part I. Salt Lake City, Utah: Utah Academy of Sciences, Arts and Letters.

ACC 094509 05001465 Crosby, D.G.; Tucker, R.K. (1966) Toxicity of Aquatic Herbicides to Daphnia magna. Science 154(3746):289 -291. Study conducted at the Agricultural Toxicology and Residue Research Laboratory, University of California, Davis. Submitted by Pennwalt Corp., Pet#1F1105, Acc# 094509 (exhibit C-109), 12/01/70). Test ID# ES-H2.

05001497 Sanders, H.O. (1970) Toxicities of some herbicides to six species of freshwater crustaceans. Journal of the Water Pollution Control Federation 42(8):1544-1550.

71142 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate) Technical 89.5% Acid Equivalent to the Fiddler Crab, Uca pugilator: UCES Project No. 11506 -41-11. (Unpublished study received Jan 23, 1981 under 4581 -174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-O)

72464 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate) Technical 89.5% Acid Equivalent to the Fiddler Crab, Uca pugilator:

### 56 UCES Project No. 11506-41-11. (Un- published study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-O)

74224 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate) Technical 89.5% Acid Equivalent to the Fiddler Crab, Uca pugilator: UCES Project No. 11506 -41-11. (Unpublished study received Jan 23, 1981 under 4581 -282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-O).

71145 ACC# 244122 Bailey, H.C. (1980) Letter sent to Bernalyn D. McGaughey dated Sep 19, 1980 (Summary of results of 48 -hour mussel embryo bio- assay performed on Endothall): SRI Project LSC -1514-6. (Unpublished study, including letter d ated Jun 20, 1980 from H.C. Bailey to Bernalyn D. McGaughey, received Jan 23, 1981 under 4581 -174; prepared by SRI International, submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131 -R) Toxicity of 89.5 acid equiv. to mussel embryos. 1980 study SRI Labs.

74227 Bailey, H.C. (1980) Letter sent to Bernalyn D. McGaughey dated Sep 19, 1980 Results of 48 -hour mussel embryo bioassay performed on Endothal|: SRI Project LSC- 1514-6. (Unpublished study received Jan 23, 1981 under 4581 -282; prepared by SRI International, submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-R).

83026 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate), 89.5% Acid Equivalent, to the Grass Shrimp Palaemonetes pugio: UCES Project No. 1150 6-41-10. (Unpublished study received Jan 23, 1981 under 4581 -174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-L)

83108 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate), 89.5% Acid Equivalent, to the Grass Shrimp Palaemonetes pugio: UCES Project No. 11506 -41-10. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-L)

84151 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Endothall (Acid Monohydrate), 89.5% Acid Equivalent, to the Grass Shrimp Palaemonetes pugio: UCES Project No. 11506 -41-10. (Unpublished study received Jan 23, 1981 under 4581 -282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-L)

42895201 Dionne, E. (1993) Endothall Technical--Acute Toxicity to Eastern Oyster (Crassostrea virginica) Under Flow -through Conditions: Final Report: Lab Project Number: 93- 4- 4715: 12442.0591.6125.504. Unpublished study prepared by Springborn Laboratories, Inc. 68 p.

42914101 Bettencourt, M. (1993) Endothall Technical-Acute Toxicity to Mysid Shrimp (Mysidopsis bahia) Under Flow -Through Conditions: Final Report: Lab Project Number: 12442.0591.6124.515: 93 -3- 4711. Unpublished study prepared by Springborn Labs, Inc. 67 p.

42914102 Bettencourt, M. (1993) Endothall Technical-Acute Toxicity to Sheepshead Minnow (Cyprinodon variegatus) Under Flow

- Through Conditions: Final Report: Lab Project Number: 92 -1- 4901: 12442.0591.6123.505. Unpublished study prepared by Springborn Labs, Inc. 65 p.

### 57 25816 Davis, H.C.; Hidu, H. (19??) Effects of pesticides on embryonic development of Clams and Oysters and on survival and growth of the Larvae. Fishery Bulletin 67(2):393

- 400,403. (Also In unpublished submission received Jan 2, 1980 under 2217-485; submitted by PBI-Gordon Corp., Kansas City, Kans.; CDL:241581-W)

26244 Miller, C.W.; Lowe, J.I. (19??) Toxicity of Herbicides to Estuarine Animals. (U.S. Bureau of Commercial Fisheries, unpublished report.)

40228401 Mayer, F.L. (1986). Acute Toxicity Handbook of Chemicals to Estuarine Organisms. Prepared for Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency (USEPA), Prepared by Environmental Research Laboratory, Office of Research and Development, USEPA, Gulf Breeze, FL 32561. 274p.

43007801 Putt, A. (1993) Endothall Technical (Acid)--The Chronic Toxicity to Daphnia magna Under Flow-Through Conditions: Final Report: Lab Project Number: 92-11-4525: 12442.0692.6148.130. Unpublished study prepared by Springborn Labs, Inc. 99 p.

43295401 Bettencourt, M. (1994) Endothall Technical (Acid)--The Toxicity to Fathead Minnow (Pimephales promelas) During an Early Life -stage Exposure: Final Report: Lab Project Number: 93 -1- 4567: 12442.0692.6149.120. Unpublished study prepared by Springborn Labs, Inc. 84 p.

48157201 Paul, E.; Simonin, H.; Symuyla, J. (2010) The Toxicity of Diquat, Endothall, and Fluridone to Early Life Stages of Fish. Project Number: FLURIDONE/01/10/04. Unpublished study prepared by SePRO Corporation. 23 p. (E014903 Open Literature Study)

45088229 Hiltibran, R. (1967) Effect of Some Herbicides on Fertilized Fish Eggs and Fry. Trans. Am. Fish. Soc. 96:414-416. (ACC#094509)

44949201 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 96-Hour Toxicity Test with the Freshwater Diatom (Navicula pelliculosa): Final Report: Lab Project Number: 299A

- 102. Unpublished study prepared by Wildlife International Ltd. 38 p. {OPPTS 850.5400}

44949202 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 96-Hour Toxicity Test with the Freshwater Alga (Anabaena flos -aquae): Final Report: Lab Project Number: 299A -101. Unpublished study prepared by Wildlife Inte rnational Ltd. 36 p. {OPPTS 850.5400}

44949402 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 7-Day Toxicity Test with Duckweed (Lemna gibba G3): Final Report: Lab Project Number: 299A -105. Unpublished study prepared by Wildlife International Ltd. 34 p. {OPPTS 850.4400}

44949403 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 7-Day Toxicity Test with The Freshwater Alga (Selenastrum capricornutum): Final Report: Lab Project Number: 299A -103. Unpublished study prepared by Wildlife International Ltd. 36 p. {OPPTS 850.5400}

44976701 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191: A 96-Hour Toxicity Test with the Marine Diatom (Skeletonema costatum): Final Report: Lab Project Number: 299A -104. Unpublished study prepared by Wildlife International , Ltd. 38 p. {OPPTS 850.5400}

### 58 113952 Walsh, G. (1971) Effects of Herbicides on Photosynthesis and Growth of Marine Unicellular Algae. (Environmental Protection Agency, Gulf Breeze Laboratory; unpublished study; CDL:094506-F)

111488 Moffett, J.; Morton, H.; MacDonald, R. (1972) Toxicity of some herbicidal sprays to honey bees. Journal of Economic Entomology 65(1):32 -36. (Also In unpublished submission received Sep 26, 1974 under 464

- 323; submitted by Dow Chemical U.S.A., Midland, MI; CDL:120345-H)

35245 Pennwalt Corporation (1970) Beneficial Insect Safety. (Unpublished study received Jan 5, 1978 under 1F1105; CDL:096705-K)

ACC 094509 Morton, H.T. Letter to E.J. Bowles regarding preliminary honeybee feedingstudies. 1p. Submitted by Pennwalt Corp., Pet. #1F1105, Acc#094509 (Exhibit C38). Test ID#ES-GG6.

40960 MacEwen, J.D. (1963) Toxicity Studies on Endothal acid: Development File No. 342.44

- 11/1. (Unpublished study received Apr 10, 1966 under 6G0503; prepared by Wayne State Univ., Dept. of Industrial Medicine and Hygiene, submitted by Pennsalt Chemical Corp., Bryan, Tex.; CDL:090587-C)

75236 Brieger, H. (1950) Preliminary Toxicity Studies on Endothal. (Jefferson Medical College, Div. of Industrial Medicine for U.S. Food an d Drug Administration; unpublished study; CDL: 109911-A)

114548 Kohn, F.; Kay, D. (1968) Report to Minnesota Mining and Manufacturing Co: Acute Toxicity Studies on 3ME68H: Lifestream Laboratories Project Nos. 984 through 988. (Unpublished study received Dec 19, 1975 under 6H5112; prepared by Lifestream Laboratories, Inc., submitted by 3M Co., St. Paul, MN; CDL:225291-C)

40109202 Smith, S. (1986) Acute Oral LD50 Study in Rats with Pelletted Endothall: Project ID: 480-2553. Unpublished study prepared by American Biogenics Corp. 32 p.

42289201 Mallory, V. (1991) Acute Exposure Oral Toxicity in Rats with Endothall Technical: Lab Project Number: PH 402 -ANA-002-91. Unpublished study prepared by Pharmakon Research International, Inc. 53 p.

42169501 Cracknell, S. (1988) Endothall Technical: Acute Inhalation Toxicity Study in the Rat: Final Report: Lab Project Number: 88/0598: PSV/024. Unpublished study prepared by Life Science Research Ltd. 109 p.

42221501 Cracknell, S. (1988) Endothall Technical: Acute Inhalation Toxicity Study in the Rat: Lab Project Number: 90/PSV024/0970: 88/0598. Unpublished study prepared by Life Science Research Ltd. 5 p.

42408701 Hoffman, G. (1992) An Acute Inhalation Toxicity Study of Endothall Technical in the Rat: Lab Project Number: 91-8355. Unpublished study prepared by Bio/dynamics, Inc. 132 p.

42169502 42200101 Hallifax, D. (1990) Endothall Technical: Absorption, Distribution, Metabolism and Excretion Study in the Rat: Final Report: Lab Project Number: 89/0122: PSV/026/ENDOTHALL. Unpublished study prepared by Life Science Research Ltd. 381 p.

### 59 42169503 Johnson, J.; Mahon, C.; Killinger, J. (1990) Dermal Absorption of Carbon 14- Endothall Monohydrate Using Sprague -Dawley Rats: Lab Project Number: N4900-1000. Unpublished study prepared by Battelle Columbus Division. 225 p.

43152101 Trutter, J. (1993) Two-Generation Reproduction Study in Rats with Disodium Salt of Endothall: Final Report: Lab Project Number: 153/142. Unpublished study prepared by Hazleton Washington, Inc. 1479 p.

43629301 Trutter, J. (1995) Two-Generation Reproduction Study in Rats with Disodium Salt of Endothall: Addendum to MRID 43152101: Lab Project Number: 153 -142. Unpublished study prepared by Hazleton Washington, Inc. 21 p.

31855 Blackburn, R.D.; Weldon, L.W. (1964) Control of Southern Naiad in Florida drainage and irrigation channels. Weeds 12(4):295 -298. (Also In unpublished submission received Sep 15, 1972 under 1F1101; submitted by Chevron Chemical Co., Richmond, Calif.; CDL:090862-AE)

36529 Carlson, R.E.; Sandeno, J.L. (1970) Effect of Endothall on the Growth of Several Fungi. (Unpublished study received Jan 5, 1978 under 1F1105; submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096704-B)

114556 Carlson, R.; Sandeno, J. (1970) Effect of Endothall on the Growth of Several Fungi. (Unpublished study received Oct 26, 1978 under 4581

- 282; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:235432-B)

72467 U.S. Department of Interior, Bureau of Reclamation (1964?) Results of Algaecidal Evaluation Tests of Selected Compounds: Report No. WC

- 21. Annual progress rept. of 1964, lab. Studies. (Unpublished study; CDL:099883-U)

74228 Pennwalt Corporation (19??) Toxicity Testing Protocols: Mussel Embryo Test. (Unpublished study received Jan 23, 1981 under 4581-282; CDL:244122-S)

80439 Montgomery, M.L.; Freed, V.H. (1964) Preliminary Study on Microbial Effect on Endothal. (Unpublished study received Feb 4, 1966 under 6G0503; prepared by Oregon State Univ., Dept. of Agricultural Chemistry, submitted by Pennsalt Chemicals Corp., Tacoma, Wash.; CDL:090585-D)

86622 Scribner, J.D. (1981) Evaluation of Studies on Genetic Toxicity of Endothall. (Unpublished study received Jul 29, 1981 under 4581

- 204; submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:245680-D)

114492 Pennwalt Corp. (1972) Responses of Plankton and Macrofauna Communities To Test Application of Chemical Herbicides. (Unpublished study received Jul 9, 1975 under 1F1105; CDL:094702-H)

114493 Walker, C. (1971) The toxicological effects of herbicides and weed control on fish and other organisms in the aquatic ecosystem. By U.S. Fish and Wildlife Service, Div. of Fishery Research, Branch of Pest Control Research. Pages 119

- 126, In Proc. Eur. Weed Res. Coun. 3rd Int. Symp. Aquatic Weeds; 1971. S.l.: s.n. (Also In unpublished submi ssion received Jul 9, 1975 under 1F1105; submitted by Pennwalt Corp., Tacoma, WA; CDL: 094702-I)

136298 House, W.; Goodson, L.; Gadberry, H.; et al. (1967) Assessment of Ecological Effects of Extensive or Repeated Use of Herbicides: MRI Project No. 3103 -B ; Contract No. DAHC15 -68-C- 0119. Final rept. (Unpublished study received Aug 12, 1970 under 1E1046; submitted by Department of the Army, N. Fort Mead, MD; CDL: 093358-C)

### 60 138449 Sikka, H.; Saxena, J. (19??) Metabolism of endothall by aquatic microorganisms. J. Agr. Food Chem. 21(3). (Also In unpublished submission received Feb 1, 1975 under 4581 -EX-21; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:094726-B)

44820104 Giddings, J. (1999) Ecological Risk Assessment of Aquatic Herbicides Containing Endothall: Final Report: Lab Project Number: KP -98-31: 98-11-7564: 12442- 0898- 6271

- 251. Unpublished study prepared by Elf Atochem and Springborn Laboratories, Inc. 64 p

67174 Schreck, C.B. (1974) Aquatic Plant Control Using Herbicides in a Large Potable Water Supply Reservoir: Contract No. DACW65 -74- C- 0013. (Virginia Polytechnic Institute and State Univ., Dept. of Fisheries and Wildlife Sciences for U.S. Dept. of the Army, Corps of Engineers; unpublished study; CDL:231433-D)

38643 Schreck, C.B.; Berry, C.R.; Strange, R.J.; et al. (1974) Ecosystem Studies on the Use of Diquat and Endothal for Aquatic Plant Control in a Large Potable Water Supply Reservoir: Contract No. DAW-65-74-C- 0013. (Virginia, Commission of Game and Inland Fisheries and Virginia Polytechnic Institute and State Univ., Dept. of Fisheries and Wildlife Sciences for U.S. Dept. of the Army, Office of the Chief of Engineers, Aquatic Plant Control Program, I nteragency Technical Advisory Committee, unpublished study; CDL:095428-Y)

114495 Schreck, C. (1974) Aquatic Plant Control Using Herbicides in a Large Potable Water Supply Reservoir: Contract No. DACW65 -74-C-0013. Annual rept., Jul 1, 1973- Jun 30, 1974. (Virginia Polytechnic Institute and State Univ., Dept. of Fisheries and Wildlife Sciences for U.S. Dept. of the Army, Corps of Engineers; unpublished study; CDL:094702-L)

46269 Swabey, Y.H.; Schenk, C.F. (1963) Report on Algicides and Aquatic Herbicides. (Ontario, Water Resources Commission, Laboratory Division, Biology Branch, unpublished study; CDL:107773-B)

55714 Silvo, O.E.J. (1967) Alustavia Tutkimuksia Eraiden Herbisidien Myrkyllisyydesta Nuorille Karpin Poikasille (Cyprinus carpio L.). N.P. (Suomen Kalatalous 32 Finlands Fiskerier; incomplete; also in unpublished submission received Jul 11, 1961 under 1E1046; submitted by U.S. Dept. of the Army, Washington, D.C.; CDL:093359-X)

102855 Silvo, O. (1967) Alustavia Tutkimuksia Eraiden Herbisidien Myrkyllisyydesta Nuorille Karpin Poikasille (Cyprinus catpio L.). Helsinki, Fin.:s.n.|. (Suomen Kalatalous 32; also In unpublished submission received Feb 3, 1976 under 960

- 163; submitted by Balcom Chemicals, Inc., Greeley, CO; CDL:228944-V).

100609 Schreck, C.; Corning, R.; Berry, C.; et al. (1974) Aquatic Plant Control Using Herbicides in a Large Potable Water Supply Reservoir. Annual rept., Jul 1, 1973--Jun 30, 1974: Contract N o. DACW65-74-C-0013. (Virginia Polytechnic Institute and State Univ., Dept. of Fisheries and Wildlife Sciences for U.S. Dept. of the Army, Corps of Engineers; unpublished study; CDL:247354-B)

113925 Agchem (1959) Environmental Studies on Endothall. (Compilation; unpublished study received Dec 3, 1959 under 4581-139; CDL: 007440-A)

113971 Pennwalt Corp. (1970) Full Reports of Investigations Made with Respect to the Safety of the Product: Endothall|. (Compilation; unpublished study received on unknown date under 1F1105; CDL:094509-A)

### 61 Disodium Salt of Endothall

MRID Citation Reference

85213 Inglis, A.; Davis, E.L. (1972) Effects of Water Hardness on the Toxicity of Several Organic and Inorganic Herbicides to Fish. By U.S. Fish and Wildlife Service, FishPesticide Research Laboratory. Washington, D.C.: USFWS. (Technical papers of the Bureau of Sport Fisheries and Wildlife 67; published study; CDL: 232666-L)

96298 Walker, C.R. (1963) Endothal derivatives as aquatic herbicides in fishery habitats. Weeds 11(3):226

- 232. (Also In unpublished submission received Feb 17, 1967 under 7F0570; submitted by Pennsalt Chemicals Corp., Bryan, Tex.; CDL:090719-J)

99330 Applied Biochemists, Incorporated (1972) The Effect of Various Concentrations of Copper from Cutrine and Various Concentrations of Endothal (Dipotassium Salt) on Bluegills (Lepomis macrochirus Rafinesque). (Unpublished study received Dec 21, 1972 under unknown admin. no.; CDL:127670-E)

102626 Inglis, A.; Davis, E. (1968) The Effect of Water Hardness on the Toxicity to Fish of Several Organic and Inorganic Herbicides. (Unpublished paper presented at the 8th meeting of the Weed Society of America, Feb 5

- 8,1968, New Orleans, LA; unpublished study received Jul 18, 1972 under 2E1221; submitted by U.S. Dept. of the Army, Washington, DC; CDL:091051-R)

107923 Walder, C. (1964) Toxicological effects of herbicides on the fish environment. Water & Sewage Works 111 (3):113 -116. (Also In unpublished submission received Jul 18, 1972 under 2E1221; submitted by U.S. Dept. of the Army, Washington, DC; CDL:091051-V)

113925 Agchem (1959) Environmental Studies on Endothall. (Compilation; unpublished study received Dec 3, 1959 under 4581-139; CDL: 007440-A)

113971 Pennwalt Corp. (1970) Full Reports of Investigations Made with Respect to the Safety of the Product: Endothall|. (Compilation; unpublished study received on unknown date under 1F1105; CDL:094509-A)

114508 Hiltibran, R. (1959) Letter sent to H. Lindaberry dated May 28, 1959 AUR 466-W-10 toxicity to bluegills. (Illinois, Natural History Survey Div.; unpublished study; CDL:007441-H)

114509 Walker, C. (1958) Letter sent to H. Lindaberry dated May 13, 1958 (Study: Endothall toxicity to fathead minnow). (Missouri, Conservation Commission; unpublished study; CDL:007441-I)

115756 Inglis, A.; Davis, E. (1972) Effects of Water Hardness on the Toxicity of Several Organic and Inorganic Herbicides to Fish. By U.S. Fish and Wildlife Service, Fish -Pesticide Research Laboratory. Washington, DC: USFWS. (Technical papers of the Bureau of Sport Fisheries and Wildlife 67; published study; CDL: 248614-P)

114493 Walker, C. (1971) The toxicological effects of herbicides and weed control on fish and other organisms in the aquatic ecosystem. By U.S. Fish and Wildlife Service, Div. of Fishery Research, Branch of Pest Control Research. Pages 119

- 126, In Proc. Eur. Weed Res. Coun. 3rd Int. Symp. Aquatic Weeds; 1971. S.l.: s.n. (Also In unpublished submission received Jul 9, 1975 under 1F1105; submitted by Pennwalt Corp., Tacoma, WA; CDL: 094702-I)

36547 Latven, A.R. (1975) Ripenthol N.B. 58-188-3 (Isopropyl-butanol Formulation). (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Pharmacology

### 62 Dipotassium Salt of Endothall

42359501 Pedersen, C.; Helsten, B. (1992) Aquathol K Aquatic Herbicide: 21-Day Acute Oral LD50 Study in Mallard Ducks: Lab Project Number: 106 -006- 04. Unpublished study prepared by Bio-Life Associates, Ltd. 54 p.

99204 Applied Biochemists, Incorporated (1973) Toxicity Data for Copper-triethanolamine Complex on Ring

- necked Pheasant and Mallard Duck. (Unpublished study received Nov 21, 1973 under 8959-12; CDL:010116-B)

35238 Fink, R.; Beavers, J.B.; Brown, R. (1977) Final Report: Eight-Day Dietary LC50-- Bobwhite Quail: Project No. 110

- 111. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Wildlife International, Ltd. in cooperation with Washington College, sub - mitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096705-C)

35239 Fink, R.; Beavers, J.B.; Brown, R. (1977) Final Report: Eight-Day Dietary LC50-- Mallard Duck: Project No. 110

- 113. (Unpublished study received Jan 5, 1978 under 1F1105; pre pared by Wildlife International, Ltd. in cooperation with Washington College, sub - mitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096705-D)

99448 Schmidt, J. (1974) Subacute Toxicities of Cutrine and Weedtrine- Plus to Ring-necked Pheasants (Phasianus colchicus) & Mallard Ducks (Anus platyrhynchos): Dietary LC50. (Unpublished study received Jun 14, 1976 under 8959 -11; submitted by Applied Bio chemists, Inc., Mequon, WI; CDL:224874-B)

43167801 Pedersen, C. (1994) Aquathol K Aquatic Herbicide: 8-Day Acute Dietary LC50 Study in Bobwhite Quail: Lab Project Number: 106 -013-01: HWA 153-150. Unpublished study prepared by Bio-Life Associates, Ltd. 102 p.

43167802 Pedersen, C. (1994) Aquathol K Aquatic Herbicide: 8-Day Acute Dietary LC50 Study in Mallard Ducklings: Lab Project Number: 106 -017-02: HWA 153- 150. Unpublished study prepared by Bio-Life Associates, Ltd. 97 p.

71134 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Aquathol K to the Bluegill Sunfish, Lepomis macrochirus Rafinesque: UCES Project No. 11506 -41-16. (Unpublished study received Jan 23, 1981 under 4581

- 174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-F)

72457 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Aquathol K to the Bluegill Sunfish, Lepomis macrochirus Rafinesque: UCES Project No. 11506 -41-16. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-F)

113695 Davis, J.; Hughes, J. (1963) Further Observations on the Toxicity of Commercial Herbicides to Bluegill Sunfish. (Louisiana, Wild Life and Fisheries Commission; unpublished study; CDL: 098334-F)

83025 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Aquathol K to the Rainbow Trout, Salmo gairdneri Richardson: UCES Project No. 11506-41-15. (Unpublished Research, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096704-Y)

MRID Citation Reference

### 63 study received Jan 23, 1981 under 4581-174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-C)

83106 Vilkas, A.J.; Seminara, J. (1979) The Acute Toxicity of Aquathol K to the Rainbow Trout, Salmo gairdneri~Richardson: UCES Project No. 11506 -41-15. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-C)

96295 Walker, C.R. (1963) Letter sent to Harold L. Lindaberry dated Nov 8, 1963 Fish toxicity studies|. (U.S. Fish and Wildlife Service, Fish Control Laboratory; unpublished study; CDL:090719-G)

113971 Pennwalt Corp. (1970) Full Reports of Investigations Made with Respect to the Safety of the Product: Endothall. (Compilation; unpublished study received on unknown date under 1F1105; CDL:094509-A )

114494 Folmar, L. (19??) Letter sent to E. Bowles circa Dec 13, 1974 Aquathol K. (U.S. Dept. of the Interior, Bureau of Reclamation, Engineering and Research Center, Denver Fish Pesticide Unit; unpublished study; CDL:094702-K)

114511 Cope, O. (1965) Letter sent to E. Bowles dated Jul 23, 1965 Toxicity study of several Pennsalt herbicides against rainbow trout. (U.S. Fish and Wildlife Service, FishPesticide Research Laboratory; unpublished study; CDL:007441-K)

114513 U.S. Fish and Wildlife Service, Fish Control Laboratory (19??) Toxicity Study of Selected Test Chemicals on Rainbow Trout, Goldfish, Black Bullhead, and Bluegill|. (Unpublished study; CDL:007441-M)

116471 McCann, J. (1969) Aquathol Plus Granular: Bluegill (Lepomis macrochirus)|. (U.S. Agricultural Research Service, Pesticides Regulation Div., Animal Biology Laboratory; unpublished study; CDL:132041-A)

42695401 Bettencourt, M. (1993) Aquathol K (Dipotassium Salt of Endothall)--Acute Toxicity to Bluegill Sunfish (Lepomis macrochirus) under Flow- through Conditions: Final Report: Lab Project Number: 92 -3- 4192: 1244.0591.6133.105. Unpublished study prepared by Springborn Labs, Inc. 62 p.

42695402 Bettencourt, M. (1993) Aquathol K (Dipotassium Salt of Endothall)--Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss) under Flow

- through Conditions: Final Report: Lab Project Number: 92 -3- 4163: 12442.0591.6132.108. Unpublished study prepared by Springborn Labs, Inc. 63 p.

71138 Vilkas, A.G.; Browne, A.M. (1979) The Acute Toxicity of Aquathol K 28.6% Acid Equivalent Lot No. ACC - 06M8-04, NB84-5-10 to the Water Flea, Daphnia magna Straus: UCES Project No. 11506 -41-14. (Unpublished study received Jan 23, 1981 under 4581 -174; pre- pared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-J)

83107 Vilkas, A.G.; Browne, A.M. (1979) The Acute Toxicity of Aquathol K 28.6% Acid Equivalent Lot No. ACC -06M8-04, NB84-5-10 to the Water Flea, Daphnia magna Straus: UCES Project No. 11506-41- 14. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.;CDL:099883-J)

### 64 84150 Vilkas, A.G.; Browne, A.M. (1979) The Acute Toxicity of Aquathol K 28.6% Acid Equivalent Lot No. ACC -06M8-04, NB84-5-10 to the Water Flea, Daphnia magna Straus: UCES Project No. 11506 -41-14. (Unpublished study received Jan 23, 1981 under 4581 -282; pre- pared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-J)

42695403 Putt, A. (1993) Aquathol K (Dipotassium Salt of Endothall)--Acute Toxicity to Daphnids (Daphnia magna) under Flow

- through Conditions: Final Report: Lab Project Number: 92 -3- 4153: 12442.0591.6134.115. Unpublished study prepared by Springborn Labs, Inc. 69 p.

42695404 Dionne, E. (1993) Aquathol K (Dipotassium Salt of Endothall)--Acute Toxicity to Eastern Oyster (Crassostrea virginica) under Flow -through Conditions: Final Repo rt: Lab Project Number: 92 -3- 4149: 12442.0591.6137.504. Unpublished study prepared by Springborn Labs, Inc. 66 p.

42695405 Bettencourt, M. (1993) Aquathol K (Dipotassium Salt of Endothall)--Acute Toxicity to Sheepshead Minnow (Cyprinodon variegatus) unde r Flow- through Conditions: Final Report: Lab Project Number: 92 -2-4110: 12442.0591.6135.505. Unpublished study prepared by Springborn Labs, Inc. 64 p.

42695406 Bettencourt, M. (1993) Aquathol K (Dipotassium Salt of Endothall)--Acute Toxicity to Mysid Shr imp (Mysidopsis bahia) under Flow- through Conditions: Final Report: Lab Project Number: 92 -9-4411: 12442.0591.6136.515. Unpublished study prepared by Springborn Labs, Inc. 66 p.

41149 Davis, J.T.; Hughes, J.S. (1963) Further observations on the toxicity of commercial herbicides to bluegill sunfish. Proceedings of the Southern Weed Control Conference: 337

- 340. (Also In unpublished submission received on unknown date under 8F0660; submitted by Dow Chemical U.S.A., Midland, Mich.; CDL:094930

- M) CDL: 098334-F) Louisiana, Wild Life and Fisheries Commission

46269 ACC 094509 Swabey, Y.H.; Schenk, C.F. (1963) Report on Algicides and Aquatic Herbicides. (Ontario, Water Resources Commission, Laboratory Division, Biology Branch, unpublished study; CDL:107773-B). 22p.

48769 Berry, C.R. (1974) Acute Toxicity of Diquat, Endothal, and a Mixture of the Two to Bluegill Sunfish: Contract No. DACW65 -74-C- 0013. (Virginia Polytechnic Institute and State Univ., Dept. of Fisheries and Wildlife Sciences for U.S. Dept. of the Army, Corps of Engineers, unpublished study; CDL:231436-E)

48770 Berry, C.R. (1974) Effect of Diquat and Endothall Separately and Combined on Bluegill Ventilation Rate: Contract No. DACW65-74- C-0013. (Virginia Polytechnic Institute and State Univ., Dept. of Fisheries and Wildlife Sciences for U.S. Dept. of the Army, Corps of Engineers, unpublished study; CDL:231436-F)

84991 Landolt, M.L.; Felton, S.P.; Liguori, V.M.; et al. (1981) Toxicity of Endothall to Juvenile Chinook Salmon (Oncorhynchus tshaw

- ytscha). Final rept. (Washington, Dept. of Fisheries for U.S. Army Corps of Engineers, Waterways Experiment Station, Aquatic Plant Control Research Program; unpublished study, including published data and letters dated Aug 5, 1981 from B.D. Gaughey to Gary Wedemeyer and Aug 27, 1981 from G.A. Wedemeyer to Bernalyn D. McGaughey; CDL:246080-A)

### 65 113971 Pennwalt Corp. (1970) Full Reports of Investigations Made with Respect to the Safety of the Product: Endothall. (Compilation; unpublished study received on unknown date under 1F1105; CDL:094509-A) Dragonfly, Damselfly aquatic larvae stage toxicity

36568 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E-5656. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-AW)

36576 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E-5686. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-BE)

40959 Eibert, J., Jr. (1966) Acute Oral Toxicity (LD50) Study in Rats: S.A. No. 106319. (Unpublished study received Apr 10, 1966 under 6G0503; prepared by Scientific Associates, Inc., submitted by Pennsalt Chemical Corp., Bryan, Tex.; CDL:090587-B)

78209 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Aquathol K: Lab No. 7E -5656. (Unpublished study received Jan 5, 1978 under 4581- 174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, PA; CDL:232580-AJ)

78216 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E-5686. (Unpublished study received Jan 5, 1978 under 4581 -174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:232580-AR)

81407 Eibert, J., Jr. (1966) Acute Oral Toxicity (LD50) Study in Rats: S.A. No. 106319. (Unpublished study received Apr 14, 1966 under 4581 -70; prepared by Scientific Associates, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:051133-K)

84612 Ralston Purina Company (1981) Aquathol Granular Aquatic Herbicide: RT Lab No. 844059. (Unpublished study received Sep 14, 1981 under 4581 -349; submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:246012-J)

97831 Reagan, E.L.; Becci, P.J.; Parent, R.A. (1981) Acute Oral Toxicity in Rats: FDRL Study No. 6915A. (Unpublished study received Sep 14, 1981 under 4581

- 349; prepared by Food and Drug Research Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:246012-L)

97832 Reagan, E.L.; Becci, P.J.; Parent, R.A. (1981) Acute Oral Toxicity in Rats: FDRL Study No. 6915A. (Unpublished study received Sep 14, 1981 under 4581

- 349; prepared by Food and Drug Research Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:246012-M)

97833 Reagan, E.L.; Becci, P.J.; Parent, R.A. (1981) Acute Oral Toxicity in Rats: FDRL Study No. 6915A. (Unpublished study received Sep 14, 1981 under 4581

- 349; prepared by Food and Drug Research Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:246012-N)

104758 Reagan, E.L.; Becci, P.J.; Parent, R.A. (1981) Acute Oral Toxicity in Rats: FDRL Study No. 6915A. (Unpublished study received Sep 14, 1981 under 4581

- 349; prepared by Food and Drug Research Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:246012-K)

### 66 113939 Van Duuren, B. (1972) Gastric Feeding in Rats: Beta-Propiolactone and Endothall. (Unpublished study received May 31, 1972 under 1F1105; prepared by New York Medical Center, submitted by Pennwalt Corp., Tacoma, WA; CDL:094506-C)

42289101 Mallory, V. (1991) Acute Exposure Oral Toxicity in Rats with Pelletized Aquathol K: Lab Project Number: PH 402 -ANA-008- 91. Unpublished study prepared by Pharmakon Research International, Inc. 42 p.

42338901 Mallory, V. (1991) Acute Exposure Oral Toxicity in Rats with Aquathol K: Lab Project Number: PH 402 -ANA-004- 91. Unpublished study prepared by Pharmakon Research Intl. 55 p.

44319605 Wnorowski, G. (1997) Acute Oral Toxicity Defined LD50 (in Rats): ThinRite: Lab Project Number: 5071:P320. Unpublished study prepared by Product Safety Labs. 25 p.

44320104 Wnorowski, G. (1996) Acute Oral Toxicity Defined LD50 (in Rats): Aquathol Super K Granule: Lab Project Number: 4878: P320. Unpublished study prepared by Product Safety Labs. 26 p.

49074404 Lowe, C. (2012) Acute Oral Toxicity Up and Down Procedure in Rats. Project Number: 34449, P320. Unpublished study prepared by Eurofins/Product Safety Laboratories. 15p.

36561 Wise, M.T. (1977) Acute Inhalation Toxicity of a) Aquathol® K (N.B. 77-100-4) b) Hydrothol® 191 Liquid (N.B. 77 -100-2) c) Hydrothol® 47 Liquid (N.B. 77-100- 3) d) Aquathol® (N.B. 77 -99-7) e) Des-I-Cate® Accelerate (N.B. 77-99-6) f) Knox- Out® 2 FM (N.B. 4414 -94): Laboratory Nos. a) 7E-5660 b)7E-5665 c) 7E-5670 d) 7E- 5675 e) 7E -5680 f) 7E- 5685. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096704-AO)

36592 Zeigler, R.L. (1977) Acute Inhalation Toxicity of 1. Aquathol® Granular (N.B. 77-99-4) 2. Hydrothol® 191 Granular (N.B. 77 - 99-2) 3. Hydrothol® 47 Granular (N.B. 77- 99-3) 4. HydoutTM (N.B. 77 -99-5): Laboratory Nos. 1. 7E-5690 2. 7E-5695 3. 7E-5700 4. 7E5705. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-BU)

78202 Wise, M.T. (1977) Acute Inhalation Toxicity of Aquathol® K (N.B. 77-100-4); Hydrothol® 191 Liquid (N.B. 77 -100-2); Hydrothol® 47 Liquid (N.B. 77-100-3); Aquathol® (N.B. 77 -99-7); Des-i-cate® Accelerate (N.B. 77-99-6); Knox- out® 2 FM (N.B. 4414 -94): Laboratory Nos. 7E-5660; 7E-5665; 7F- 5670; 7E-5675; 7E- 5680; 7E5685. (Unpublished study received Jan 5, 1978 under 4581-174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL: 232580-AB)

78610 Zeigler, R.L. (1977) Acute Inhalation Toxicity of 1. Aquathol® Granular (N.B. 77-99- 4); 2 . Hydrothol® 191 Granular (N.B. 77-99- 2); 3. Hydrothol® 47 Granular (N.B. 77- 99

- 3); 4. HydoutTM (N.B. 77 -99-5): Laboratory Nos. 7E-5690; 7E- 5695; 7E- 5700; 7E5705. (Unpublished study received Jan 5, 1978 under 4581

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42407101 Hoffman, G. (1992) An Acute Inhalation Toxicity Study of Aquathol K in the Rat: Lab Project Number: 91/8357. Unpublished study prepared by Bio/dynamics, Inc. 133 p.

42407102 Hoffman, G. (1992) An Acute Inhalation Toxicity Study of Pelletized Aquathol K in the Rat: Lab Project Number: 91

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### 67 44319607 Wnorowski, G. (1997) Acute Inhalation Toxicity Limit Test (in Rats): ThinRite: Lab Project Number: 5076: P330. Unpublished study prepared by Product Safety Labs. 24 p.

49074406 Lowe, C. (2012) Acute Inhalation Toxicity Study in Rats - Limit Test. Project Number: P330, 34451. Unpublished study prepared by Eurofins/Product Safety Laboratories. 25p.

43152101 Trutter, J. (1993) Two-Generation Reproduction Study in Rats with Disodium Salt of Endothall: Final Report: Lab Project Number: 153/142. Unpublished study prepared by Hazleton Washington, Inc. 1479 p.

43629301 Trutter, J. (1995) Two-Generation Reproduction Study in Rats with Disodium Salt of Endothall: Addendum to MRID 43152101: Lab Project Number: 153

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42396401 Hoberg, J. (1992) Dipotassium Salt of Endothall--Toxicity to the Freshwater Bluegreen Alga Anabaena flos -aquae: Final Report: Lab Project Number: 91-12-4035. Unpublished study prepared by Springborn Laboratories, Inc. 59 p.

42396402 Hoberg, J. (1992) Dipotassium Salt of Endothall--Toxicity to the Freshwater Diatom Navicula pelliculosa: Final Report: Lab Project Number: 91 -12-4049. Unpublished study prepared by Springborn Laboratories, Inc. 61 p.

42396403 Hoberg, J. (1992) Dipotassium Salt of Endothall--Toxicity to the Freshwater Green Alga, Selenastrum capricornutum: Final Report: Lab Project Number: 91 -12-4053. Unpublished study prepared by Springborn Laboratories, Inc. 61 p.

42396404 Hoberg, J. (1992) Dipotassium Salt of Endothall--Toxicity to the Marine Diatom, Skeletonema costatum: Final Report: Lab Project Number: 92 -1- 4063. Unpublished study prepared by Springborn Laboratories, Inc. 60 p.

44392801 Hoberg, J. (1997) Dipotassium Salt of Endothall--Toxicity to the Freshwater Green Alga, Selenastrum capricornutum: Supplemental Information to Final Report (MRID #423964 -03): Lab Project Number: 91-12-4053A: 12442.0391.6118.430A: BR-91- 58A. Unpublished study prepared by Springborn Labs, Inc. 49 p.

44392802 Hoberg, J. (1997) Dipotassium Salt of Endothall--Toxicity to the Freshwater Diatom, N avicula pelliculosa: Supplemental Information to Final Report (MRID #426964- 02): Lab Project Number: 91 -12-4049A: 12442.0391.6118.440A: BR-91- 57A. Unpublished study prepared by Springborn Labs, Inc. 49 p.

44408801 Hoberg, J. (1997) Dipotassium Salt of Endothall--Toxicity to the Freshwater Blue-Green Alga, Anabaena flos -aquae: Final Report: Lab Project Number: 91-12-4035A: 12442.0391.6118.420A: BR -91-56A. Unpublished study prepared by Springborn Labs, Inc. 46 p.

42396405 Hoberg, J. (1992) Dipotassium Salt of Endothall--Determination of Effects on Seed Germination, Seedling Emergence and Vegetative Vigor of Ten Plant Species: Final Report: Lab Project Number: 91 -11-4015: 12442.0391.6117.610: BR-91-55. Unpublished study prepared by Springborn Laboratories, Inc. 353 p.

44392803 Hoberg, J. (1997) Dipotassium Salt of Endothall--Determination of the Effects on Seed Germination, Seedling Emergence and Vegetative Vigor of Ten Plant Species: Supplemental Information to Final Report (MRID #423964

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### 68 42396406 Hoberg, J. (1992) Dipotassium Salt of Endothall--Toxicity to the Duckweed Lemna gibba: Final Report: Lab Project Number: 92 -2-4097: 12442.0391.6118.410: BR-91 -54. Unpublished study prepared by Springborn Laboratories, Inc. 45 p.

44392801 Hoberg, J. (1997) Dipotassium Salt of Endothall--Toxicity to the Freshwater Green Alga, Selenastrum capricornutum: Supplemental Information to Final Report (MRID #423964 -03): Lab Project Number: 91-12-4053A: 12442.0391.6118.430A: BR-91- 58A. Unpublished study prepared by Springborn Labs, Inc. 49 p.

44392802 Hoberg, J. (1997) Dipotassium Salt of Endothall--Toxicity to the Freshwater Diatom, N avicula pelliculosa: Supplemental Information to Final Report (MRID #426964- 02): Lab Project Number: 91 -12-4049A: 12442.0391.6118.440A: BR-91- 57A. Unpublished study prepared by Springborn Labs, Inc. 49 p.

44408801 Hoberg, J. (1997) Dipotassium Salt of Endothall--Toxicity to the Freshwater Blue-Green Alga, Anabaena flos -aquae: Final Report: Lab Project Number: 91-12-4035A: 12442.0391.6118.420A: BR -91- 56A. Unpublished study prepared by Springborn Labs, Inc. 46 p.

44976701 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191: A 96-Hour Toxicity Test with the Marine Diatom (Skeletonema costatum): Final Report: Lab Project Number: 299A

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71149 Morton, H.L.; Moffett, J.O.; MacDonald, R.H. (1972) Toxicity of herbicides to newly emerged honey bees. Environmental Entomology 1(1):102

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ACC 094509 Morton, H.T. Letter to E.J. Bowles regarding preliminary honeybee feeding studies. 1p. Submitted by Pennwalt Corp., Pet. #1F1105, Acc#094509 (Exhibit C

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42644001 Dionne, E. (1992) Dipotassium Salt of Endothall: Bioconcentration and Elimination of (carbon 14) -residues with Bluegill Sunfish: Final Report: Lab Project Number: 92-5

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43315801 Dionne, E. (1994) Metabolism of Endothall Dipotassium Salt in Bluegill Sunfish (Lepomis macrochirus): Identification and Characterization of Metabolites in Fillet and Viscera: Lab Project Number: 12442.0391.6115.180: BR -91-53: 94-2-5168. Unpublished study prepared by Springborn Labs, Inc. and XenoBiotic labs Inc. 155 p.

44820102 Dionne, E.; Sharp, J.; Formella, T. (1999) Dipotassium Salt of Endothall: A Freshwater Fish and Shellfish Magnitude of Residues Study in a Static Aquatic System: Lab Project Number: KP -97-14: 52897/171.4/FIF RA: EN1115.95. Unpublished study prepared by Elf Atochem and ABC Laboratories, Inc. 213 p. {OPPTS 860.1400}

26244 Miller, C.W.; Lowe, J.I. (19??) Toxicity of Herbicides to Estuarine Animals. (U.S. Bureau of Commercial Fisheries, unpublished report.)

30123 Davis, J.T.; Hughes, J.S. (1963) Further Observations on the Toxicity of Commercial Herbicides to Bluegill Sunfish. (Unpublished study received Jan 2, 1980 under 2217-641; prepared by Louisiana, Wild Life and Fisheries Commission, submitted by PBIGordon Corp., Kansas City, Kans.; CDL:241577-S)

### 69 35236 Pennwalt Corporation (1975) Fish and Wildlife Safety. (Unpublished study received Jan 5, 1978 under 1F1105; CDL:096705-A

35243 Vilkas, A.G. (1977) The Acute Toxicity of Aquathol® K to the Fiddler Crab, Uca pugilator: UCES Project # 11506 -41- 04. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096705-H)

35245 Pennwalt Corporation (1970) Beneficial Insect Safety. (Unpublished study received Jan 5, 1978 under 1F1105; CDL:096705-K)

35443 Pennwalt Corporation (1974) Results of Residue Determinations: Fish and Other Aquatic Organisms (Oysters, Clams, Crayfish, etc.). (Unpublished study received Jan 5, 1978 under 1F1105; CDL:096703-T)

35442 Pennwalt Corporation (1974) Results of Residue Determinations: Disappearance of Endothall in Water. (Unpublished study received Jan 5, 1978 under 1F1105; CDL:096703-S)

35453 Pennwalt Corporation (1954?) Toxicology: Endothall. (Unpublished study received Jan 5, 1978 under 1F1105; CDL:096703-AE)

36529 Carlson, R.E.; Sandeno, J.L. (1970) Effect of Endothall on the Growth of Several Fungi. (Unpublished study received Jan 5, 19 78 under 1F1105; submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096704-B)

114556 Carlson, R.; Sandeno, J. (1970) Effect of Endothall on the Growth of Several Fungi. (Unpublished study received Oct 26, 1978 under 4581

- 282; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:235432-B)

36536 Serns, S.L. (1977) Effects of Dipotassium endothall on rooted aquatics and adult and first generation bluegills. Water Resources Bulletin 13(1):71

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36539 Miller, H. (1975) Phytotoxicity: Phototoxicity to Irrigated Crops. (Unpublished study received Jan 5, 1978 under 1F1105; submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-N)

48110 Davis, J.T.; Hughes, J.S. (1963?) Further Observations on the Toxicity of Commercial Herbicides to Bluegill Sunfish. (Louisiana, Wildlife and Fisheries Commission, unpublished study; CDL: 241577-R)

56036 White, R.L.; Bounds, R.L.; Lowman, F.G.; et al. (1967) Experimental Control of Submerged Vegetation in Clear Water Lakes: Federal Aid Project No. F-2- R

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95812 Folmar, L.C. (1976) Letter sent to Edward J. Bowles dated Jun 9, 1976. Results from toxicity tests conducted on rainbow trout fertilized eggs and sac fry with Aquathol K ® . (U.S. Fish and Wildlife Service, Bureau of Reclamation, Denver Fish -Pesticide Research Unit; unpublished study; CDL:096705-J)

### 70 116458 Rock, L. (1963) Letter sent to unknown recipient dated Jan 8, 1963 Potassium Endothal: Toxicity to fish. (Illinois, Dept. of Conservation; unpublished study; CDL:110609-B)

138446 Serns, S. (1974) The Effects of a Dipotassium Endothall Treatment on the Ecology of a Small Pond. (Wisconsin, Dept. of Natural Resources, Water Resources Research Section; unpublished study; CDL:094702-J)

138964 Folmar, L. (1976) Overt avoidance reaction of rainbow trout fry to nine herbicides. Bulletin of Environmental Contamination & Toxicology 15(5):509

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138965 Folmar, L. (1978) Avoidance chamber responses of mayfly nymphs exposed to eight herbicides. Bulletin of Environmental Contamination & Toxicology 17:312 -318. (Also In unpublished submission received Feb 6, 1984 under 239- 2424; submitted by Chevron Chemical Co., Richmond, CA; CDL:252355-E)

44820104 Giddings, J. (1999) Ecological Risk Assessment of Aquatic Herbicides Containing Endothall: Final Report: Lab Project Number: KP -98-31: 98- 11- 7564: 12442 -0898-6271- 251. Unpublished study prepared by Elf Atochem and Springborn Laboratories, Inc. 64 p.

96295 Walker, C.R. (1963) Letter sent to Harold L. Lindaberry dated Nov 8, 1963 Fish toxicity studies. (U.S. Fish and Wildlife Service, Fish Control Laboratory; unpublished study; CDL:090719-G)

ACC 094509 Lowe, J.I. and P.D. Wilson. (1970) Two letters regarding accumulation and retention. 5 p. Study conducted at Gulf Breeze Laboratory, FL. Submitted by Pennwalt Corp., Pet. #1F1105, Acc#094509, (exhibit C-106), 12/01/70.

45088229 Hiltibran, R. (1967) Effect of Some Herbicides on Fertilized Fish Eggs and Fry. Trans. Am. Fish. Soc. 96:414-416. (ACC#094509)

ACC 221750 Hagen, H.K. (undated) Long and Short Term Effects of Endothall in a Colorado Mountain Lake. Submitted by Pennwalt Corp., Pet.#221750 (exhibit C-122), undated.

ACC 094702 Walker, C.R. 1971. The Toxicological Effects of Herbicides and Weed Control on Fish and Other Organisms in the Aquatic Ecosystem. Proc. Eur. Weed Res. Coun. 3 rd Int. Symp. Aquatic Weeds, pp. 119- 126. Submitted by Pennwalt Corp., Pet. #1F1105, Acc#094702, (exhibit C

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40228401 Mayer, F.L. (1986). Acute Toxicity Handbook of Chemicals to Estuarine Organisms. Prepared for Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency (USEPA), Prepared by Environmental Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (USEPA), Gulf Breeze, FL 32561. 274 p.

Acc 221750 Sikka, H.C. 1971. Fate of Herbicides in the aquatic environment. Annual Report Contract. #DACW31 -71-C-0026. (Endothall Acc#221750 Sect. D Exhibit 37).

96298 Walker, C.R. (1963) Endothal derivatives as aquatic herbicides in fishery habitats. Weeds 11(3):226-232. (Also In unpublished submission received Feb

### 71 17, 1967 under 7F0570; submitted by Pennsalt Chemicals Corp., Bryan, Tex.; CDL:090719-J)

ACC 221750 Whitley, J.R. Letter to F.E. Temby of Pennwalt Corp. 4 p. Submitted by Pennwalt Corp., Pet# 221750 (exhibit C-120). Test ID ES-GG2.

ACC 094509 Roby, R.E. 1961. Report on use of Aquathol and effects to microorganisms. 6p. Study Conducted by Passaic Valley Water Commission, N.J. Submitted by Pennwalt Corp., Pet. #1F1105, Acc.#094509 (exhibit C

— 114), 12/01/70. Test ID# ES-GG3.

40098001 Mayer, F.L. Jr, and Ellersieck, M.R. (1986) Manual of Acute Toxicity: Interpretation and Data Base for 410 Chemicals and 66 Species of Freshwater Animals. U.S. Fish and Wildlife Service. Resource Publication 160. Washington, D.C. 579 p.

05009242 Sanders, H.O. 1969. Toxicity of Pesticides to the Crustacean Gammarus lacustris. Washington, D.C. U.S. Bureau of Sport Fisheries and Wildlife. (U.S. Bureau of Sport Fisheries and Wildlife technical paper 25).

114493 Walker, C. (1971) The toxicological effects of herbicides and weed control on fish and other organisms in the aquatic ecosystem. By U.S. Fish and Wildlife Service, Div. of Fishery Research, Branch of Pest Control Research. Pages 119

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ACC 094509 Nebecker, A.V. and A.R. Gaufin. (1964). Bioassays to determine pesticide toxicity to the amphipod crustacean Gammarus lacustris. Utah Academy Proceedings, Vol. 41:64 -67. Submitted by Pennwalt Corp., Pet. #1F1105, Acc#094509 (exhibit C- 111), 12/01/70.

Mono (N,N-dimethylalkylamine) Salt of Endothall

35237 Fink, R.; Beavers, J.B.; Brown, R. (1977) Final Report: Acute Oral LD50--Bobwhite Quail: Project No. 110 -115. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Wildlife International, Ltd. in cooperation with Washington College, submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096705-B)

42359701 42359601 on DER Pedersen, C.; Helsten, B. (1992) Endothall Technical: 21-Day Acute Oral LD50 Study in Mallard Ducks: Lab Project Number: 106 -004-04. Unpublished study prepared by Bio -Life Associates, Ltd. 50 p.

92061001 Shellenberger, T. (1990) Agchem Division-Pennwalt Corp. Phase 3 Summary of MRID 00035237. Hydrothol 191 -Acute Oral LD50 Test-Bobwhite Quail: Project No. 110- 115.: 11 p.

35240 Fink, R.; Beavers, J.B.; Brown, R. (1977) Final Report: Eight-Day Dietary LC50-- Bobwhite Quail: Project No. 110 -112. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Wildlife International, Ltd. in cooperation with Washington College, sub- mitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096705-E)

35241 Fink, R.; Beavers, J.B.; Brown, R. (1977) Final Report: Eight-Day Dietary LC50--Mallard Duck: Project No. 110-114. (Unpublished study received Jan 5, 1978 under 1F1105; MRID Citation Reference

### 72prepared by Wildlife International, Ltd. in cooperation with Washington College, submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096705-F)

43167901 Pedersen, C.; Thompson, S. (1994) Hydrothol 191 Aquatic Algicide and Herbicide: 8-Day Acute Dietary LC50 Study in Bobwhite Quail: Lab Project Number: 106 -012- 01: HWA 153-148. Unpublished study prepared by Bio-Life Associates, Ltd. 100 p.

43167902 Pedersen, C.; Thompson, S. (1994) Hydrothol 191 Aquatic Algicide and Herbicide: 8-Day Acute Dietary LC50 Study in Mallard Ducklings: Lab Project Number: 106 -016- 02: HWA 153-148. Unpublished study prepared by Bio-Life Associates, Ltd. 96 p.

92061002 Shellenberger, T. (1990) Agchem Division-Pennwalt Corp. Phase 3 Summary of MRID 00035240. Eight

- day Dietary LC50 of Hydrothol 191 to Bobwhite Quail: Project No. 110- 112.: 12 p.

47861101 Stafford, J. (2009) Endothall Amine: Reproductive Toxicity Test with the Mallard Duck (Anas platyrhynchos), Following FIFRA Guideline. Project Number: 13845/4104. Unpublished study prepared by Springborn Smithers Laboratories. 254 p.

47861102 Stafford, J. (2009) Endothall Amine: Reproductive Toxicity Test with Northern Bobwhite (Colinus virginianus) Following FIFRA Guideline. Project Number: 13845/4105. Unpublished study prepared by Springborn Laboratories, Inc. 294 p.

71132 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydrothol 191 to the Rainbow Trout, Salmo gairdneri Richardson: UCES Project No. 11506 -41- 17. (Unpublished study received Jan 23, 1981 under 4581

- 174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-D)

72456 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydrothol 191 to the Rainbow Trout, Salmo gairdneri Richardson: UCES Project No. 11506 -41- 17. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-D)

84147 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydrothol 191 to the Rainbow Trout, Salmo gairdneri Richardson: UCES Project No. 11506 -41- 17. (Unpublished study, including letters dated Jan 18, 1980 from A.G. Vilkas to B.D. McGaughey and Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581

- 282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-D)

71133 Acc#244122 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hyd- out(TM) Aquatic Weed Killer Code AHE 09H901, N.B. No. 84 -112-1 to the Rainbow Trout Salmo gairdneri Richardson: UCES Project No. 11506 -41-20. (Unpublished study, including letters d ated Feb 7, 1980 from O. Keckemet to Agchem File and Jan 18, 1980 from A.G. Vilkas to B.D. McGaughey, received Jan 23, 1981 under 4581

- 174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-E)

71135 Acc#244122 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydrothol 191 to the Bluegill Sunfish, Lepomis macrochirus Rafinesque: UCES Project No. 11506 -41- 18. (Unpublished study received Jan 23, 1981 under 4581

- 174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-G)

72458 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydrothol 191 to the Bluegill Sunfish, Lepomis macrochirus Rafinesque: UCES Project No. 11506 -41- 18. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp.; submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-G)

### 73 84148 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydrothol 191 to the Bluegill Sunfish, Lepomis macrochirus Rafinesque: UCES P roject No. 11506-41- 18. (Unpublished study received Jan 23, 1981 under 4581

- 282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-G)

71136 Acc#244122 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydout(TM) Aquatic Weed Killer Code AHE 09H901, N.B. No. 84 -112-1 to the Bluegill Sunfish, Lepomis macrochirus Rafinesque: UCES Project No. 11506 -41- 19. (Unpublished study, including letter dated Feb 7 , 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581- 174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-H)

72459 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of HydoutTM Aquatic W eed Killer Code AHE 09H901, N.B. No. 84 -112-1 to the Bluegill Sunfish Lepomis macrochirus Rafinesque: UCES Project No. 11506 -41- 19. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submit - ted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-H)

84149 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of HydoutTM Aquatic Weed Killer Code AHE 09H901, N.B. No. 84 - 112-1 to the Bluegill Sunfish Lepomis macrochirus Rafinesque: UCES Project No. 11506 -41- 19. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581

- 282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL: CDL:244122-H)

71144 Acc#244122 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Hydout, 22.6% Active Ingredient to the Common Mummichog Fundulus heteroclitus (Linnaeus): UCES Project No. 11506- 41 -21. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581

- 174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-Q)

71148 Pennwalt Corporation (1980) Hydout(TM) Aquatic Algicide and Herbicide --Pellet State versus Toxicity: Project No. WT -4- 80. (Unpublished study received Jan 23, 1981 under 4581-174; CDL: 244131-V)

72466 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Hydout, 22.6% Active Ingredient to the Common Mummichog Fundulus heteroclitus (Linnaeus): UCES Project No. 11506- 41 -21. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-Q)

74226 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Hydout, 22.6% Active Ingredient, to the Common Mummichog Fundulus heteroclitus (Linnaeus): UCES Project No. 11506- 41 -21. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581

- 282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-Q)

ACC 090719 Hughes, J.S. and J.T. Davis. 1962. Toxicity of Selected Herbicides to Bluegill Sunfish. 8 p. Submitted by Pennwalt Corp., Pet. #7F0570, Acc # 090719 (exhibit C

- 18), 03/23/67. Test ID # ES-F1.

85213 Inglis, A.; Davis, E.L. (1972) Effects of Water Hardness on the Toxicity of Several Organic and Inorganic Herbicides to Fish. By U.S. Fish and Wildlife Service, Fish-

### 74 Pesticide Research Laboratory. Washington, D.C.: USFWS. (Technical papers of the Bureau of Sport Fisheries and Wildlife 67; published study; CDL: 232666-L)

96295 Walker, C.R. (1963) Letter sent to Harold L. Lindaberry dated Nov 8, 1963 Fish toxicity studies|. (U.S. Fish and Wildlife Service, Fish Control Laboratory; unpublished study; CDL:090719-G)

96296 Cope, O.B. (1966) Letter sent to Edward J. Bowles dated Sep 1, 1966 Fish toxicity of Desiccate (Accelerate)|. (U.S. Fish and Wildlife Service, Fish -Pesticide Research Laboratory; unpublished study; CDL:090719-H)

96297 Pennsalt Chemicals Corporation (1967) Toxicity to Fish: Accelerate, Accelerate + Folex, and Accelerate + Sodium Chlorate. (Unpublished study received Feb 17, 1967 under 7F0570; CDL:090719-I)

102626 Inglis, A.; Davis, E. (1968) The Effect of Water Hardness on the Toxicity to Fish of Several Organic and Inorganic Herbicides. (Unpublished paper presented at the 8th meeting of the Weed Society of America, Feb 5

- 8, 1968, New Orleans, LA; unpublished study received Jul 18, 1972 under 2E1221; submitted by U.S. Dept. of the Army, Washington, DC; CDL:091051-R)

113971 Pennwalt Corp. (1970) Full Reports of Investigations Made with Respect to the Safety of the Product: Endothall. (Compilation; unpublished study received on unknown date under 1F1105; CDL:094509-A)

114511 Cope, O. (1965) Letter sent to E. Bowles dated Jul 23, 1965 Toxicity study of several Pennsalt herbicides against rainbow trout|. (U.S. Fish and Wildlife Service, Fish

- Pesticide Research Laboratory; unpublished study; CDL:007441-K)

114513 U.S. Fish and Wildlife Service, Fish Control Laboratory (19??) Toxicity Study of Selected Test Chemicals on Rainbow Trout, Goldfish, Black Bullhead, and Bluegill|. (Unpublished study; CDL:007441-M)

114514 Walker, C. (1963) Letter sent to H. Lindaberry dated Apr 24, 1963 Toxicity study of selected pesticides on test animals. (U.S. Fish and Wildlife Service, Fish Control Laboratory; unpublished study; CDL:007441-N)

114515 Howell, J. (1963) Letter sent to H. Lindaberry dated Jan 23, 1963 Toxicity of specific Pennsalt chemicals to the sea lamprey and rainbow trout|. (U.S. Fish and Wildlife Service, Bureau of Commercial Fisheries, Hammond Bay Biological Station; unpublished study; CDL:007441-O)

115756 Inglis, A.; Davis, E. (1972) Effects of Water Hardness on the Toxicity of Several Organic and Inorganic Herbicides to Fish. By U.S. Fish and Wildlife Service, Fish -Pesticide Research Laboratory. Washington, DC: USFWS. (Technical papers of the Bureau of Sport Fisheries and Wildlife 67; published study; CDL: 248614-P)

43196901 Bettencourt, M. (1994) Hydrothol 191--Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss) Under Flow -Through Conditions: Final Report: Lab Project Number: 93-8- 4891: 12442.0591.6138.108. Unpublished study prepared by Springborn Laboratories, Inc. 75 p.

43472801 Bettencourt, M. (1994) Hydrothol 191--Acute Toxicity to Bluegill Sunfish (Lepomis macrochirus) Under Flow -Through Conditions: Final Report: Lab Project Numbers: 94 -4- 5253: 12442.0394.6169.105. Unpublished study prepared by Springborn Labs, Inc. 74 p.

### 75 40098001 Mayer, F.L. Jr, and Ellersieck, M.R. (1986) Manual of Acute Toxicity: Interpretation and Data Base for 410 Chemicals and 66 Species of Freshwater Animals. U.S. Fish and Wildlife Service. Resource Publication 160. Washington, D.C. 579 p.

40094602 Johnson, W.; Finley, M. (1980) Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates: Resource Publication 137. USDI Fish and Wildlif e Service, Washington, D.C. 98 p.

49658 Pennwalt Corporation (1966) Toxicity Study: Hydrothol on Fish. (Reports by various sources; unpublished study received Jun 25, 1971 under unknown admin. no.; CDL:132475-F)

ACC 094702 Schreck, Carl B. 1974. Aquatic Plant control Using Herbicides in a Large Potable Water Supply Reservoir. pp 90

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71139 Acc#244122 Vilkas, A.G.; Browne, A.M. (1979) The Acute Toxicity of Hydout (22.6% Active) (Sample Code 84 -112-1; Lot AHE 09H9- 01) to the Water Flea Daphnia magna Straus: UCES Project No. 11506 -41-22. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581 - 174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-K)

72460 Vilkas, A.G.; Hughes, J.S. (1979) The Acute Toxicity of Endothall (Acid Monohydrate) to the Water Flea Daphnia magna Straus: UCES Project No. 11506 -41- 09. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-I)

72461 Vilkas, A.G.; Browne, A.M. (1979) The Acute Toxicity of Hydout (22.6% Active) (Sample Code 84 -112-1; Lot AHE 09H9- 01) to the Water Flea Daphnia magna Straus: UCES Project No. 11506 -41- 22. (Unpublished study received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-K)

74221 Vilkas, A.G.; Browne, A.M. (1979) The Acute Toxicity of Hydout (22.6% Active) (Sample Code 84 -112-1; Lot AHE 09H9- 01) to the Water Flea Daphnia magna Straus: UCES Project No. 11506 -41-22. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581 -282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-K)

43196902 Putt, A. (1994) Hydrothol 191--Acute Toxicity to Daphnids (Daphnia magna) Under Flow -Through Conditions: Final Report: Lab Project Number: 93-9- 4932: 12442.0591.6139.115. Unpublished study prepared by Springborn Laboratories, Inc. 87 p.

35242 Union Carbide Corporation (1977) The Acute Toxicity of Hydrothol®191 to the Water Flea, Daphnia magna Straus: UCES Project # 11506 -41- 05. (Unpublished study received Jan 5, 1978 under 1F1105; submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096705-G)

71140 Acc#244122 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Hydout, 22.6% Active Ingredient to the Grass Shrimp Palaemonetes pugio: USES Project No. 11506 -41- 23. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem

### 76 File, received Jan 23, 1981 under 4581-174; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-M)

72462 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Hydout, 22.6% Active Ingredient t o the Grass Shrimp Palaemonetes pugio: UCES Project No. 11506-41- 23. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL: 099883-M)

74222 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Hydout, 22.6% Active Ingredient to the Grass Shrimp Palaemonetes pugio: UCES Project No. 11506 -41- 23. (Unpublished study, including letter dated Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581 -282; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244122-M)

71141 Acc#244122 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydout( TM ) Aquatic Weed Killer Code AHE 09H901, N.B. No. 84 -112-1 to the Fiddler Crab, Uca pugilator: UCES Project No. 11506 -41- 24. (Unpublished study, including letters dated Jan 18, 1980 from A.G. Vilkas to B.D. McGaughey and Feb 7, 1980 from O. Keckemet to Agchem Fil e, received Jan 23, 1981 under 4581-174; pre- pared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:244131-N)

72463 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydout(TM) Aquatic Weed Killer Code AHE 09H901, N.B. No. 84-112-1 to the Fiddler Crab, Uca pugilator: UCES Project No. 11506 -41- 24. (Unpublished study, including letters dated Feb 7, 1980 from O. Keckement to Agchem File and Jan 18, 1980 from A.G. Vilkas to B.D. McGaughey, received Jan 23, 1981 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:099883-N)

74223 Vilkas, A.G.; Seminara, J. (1979) The Acute Toxicity of Hydout(TM) Aquatic Weed Killer, Code AHE 09H901, N.B. No. 84 - 112-1, to the Fiddler Crab, Uca pugilator: UCES Project No. 11506 -41- 24. (Unpublished study, including letters dated Jan 18, 1980 from A.G. Vilkas to B.D. Mc Gaughey and Feb 7, 1980 from O. Keckemet to Agchem File, received Jan 23, 1981 under 4581

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43196903 Bettencourt, M. (1994) Hydrothol 191--Acute Toxicity to Sheepshead Minnow (Cyprinodon variegatus) Under Flow

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43210001 Putt, A. (1994) Hydrothol 191--Acute Toxicity to Mysid Shrimp (Mysidopsis bahia) Under Flow -Through Conditions: Final Report: Lab Project Number: 93-10-5000: 12442.0591.6141.515. Unpublished study prepared by Springborn Labs., Inc. 72 p.

43550201 Dionne, E. (1995) Hydrothol 191--Acute Neurotoxicity to Eastern Oyster (Crassostrea virginica) Under Flow -through Conditions: Final Report: Lab Project Number: 12442.0591.6142. 504: 93-8- 4896. Unpublished study prepared by Springborn Labs, Inc.108 p.

28442 Inglis, A.; Davis, E.L. (1971) Technical Report on the Effect of Water Hardness on the Toxicity to Fish of Several Organic and Inorganic Herbicides. (Unpublished study received Jul 13, 1971 under 1E1046; prepared by U.S. Fish and Wildlife Service, Div. of Fishery Research, Fish-Pesticide Research Laboratory in cooperation with National

### 77 Museum, Bird and Mammal Laboratory, sub- mitted by U.S. Dept. of the Army, Office of the Chief of Engineers, Washington, D.C.; CDL:091865-G)

34907 Inglis, A.; Davis, E.L. (1965) The Effect of Water Hardness on the Toxicity to Fish of Several Organic and Inorganic Herbicides. (U.S. Fish and Wildlife Service, Fish

Pesticide Research Laboratory, unpublished study; CDL:091752-A)

43276501 Bettencourt, M. (1994) Hydrothol 191: The Toxicity to Fathead Minnow (Pimephales promelas) During an Early Life

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43437901 Putt, A. (1994) Hydrothol 191--The Chronic Toxicity to Daphnia magna Under FlowThrough Conditions: Final Report: Lab Project Number: 93 -11-5014: 12442.0692.6150.130. Unpublished study prepared by Springborn Labs, Inc. 117 p.

44700401 Serdar, D.; Johnson, A.; Stinson, M. (1995) Seawater Challenge of Chinook Salmon Smolts (Onc or hynchus tshawytscha) Exposed to the Aquatic Herbicide Hydrothol 191: Lab Project Number: 95 -358. Unpublished study prepared by Washington State Department of Ecology. 30 p.

51466 Lapham, V.T. (1966) Letter sent to W. Harry Culver dated Jun 24, 1966 Fish Kills. (Louisiana, Wild Life and Fisheries Commission, Aquatic Vegetation Control Research, unpublished study; CDL:132475-B)

51467 Frank, P.A. (1964) Letter sent to Edward J. Bowles dated Oct 30, 1964 Hydrothol treatment of aquatic weeds|. (U.S. Agricultural Research Service, Crops Research Div., Crop Protection Research Branch, unpublished study; CDL:132475-C)

51468 Zarbock, W.M. (1961) Letter sent to Harold Lindaberry dated Sep 20, 1961 TD191 on weeds and fish. (Ohio, Div. of Wildlife, Dept. of Natural Resources, unpublished study; CDL: 132475-D)

36560 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E5661. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-AN)

36580 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E5691. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-BI)

36588 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E5701. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-BQ)

36591 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E5676. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-BT)

51589 Latven, A.R. (1975) Letter sent to Obren Keckemet dated Jun 26, 1975 Toxicological findings with alcoholic Ripenthol and aqueous Ripenthol. (Unpublished study received

### 78 Oct 5, 1976 under 4581-173; prepared by Pharmacology Research, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:226503-B)

58572 Latven, A.R. (1971) Accelerate. (Unpublished study, including letter dated Sep 29, 1971 from A.R. Latven to Harold L. Linda - berry, received Feb 1, 1975 under 3F1416; prepared by Pharmacology Research, Inc., submitted by Pennwalt Corp., Tacoma, Wash.; CDL:093785-K)

61919 Latven, A.R. (1975) Toxicology Report for Pennwalt Agchem Division: Ripenthol N.B. 58 -188- 3 (Isopropylbutanol Formulation). (Unpublished study received Oct 5, 1976 under 4581

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61920 Latven, A.R. (1975) Toxicology Report for Pennwalt Agchem Division: Ripenthol N.B. 58 -191- 2 (Water Only Formulation). (Unpublished study received Oct 5, 1976 under 4581 -174; prepared by Pharmacology Research , Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:227610-D)

78188 Latven, A.R. (1975) Toxicology Report for Pennwalt, Agchem Division: Ripenthol N.B. 58 -188- 3 (Isopropylbutanol Formulation). (Unpublished study received Jan 5, 1978 under 4581 -174; prepared by Pharmacology Research, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:232580-K)

78189 Latven, A.R. (1975) Toxicology Report for Pennwalt, Agchem Division: Ripenthol N.B. 58 -191-2 (Water Only Formulation). (Unpublished study rec eived Jan 5, 1978 under 4581

- 174; prepared by Pharmacology Research, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:232580-L)

78220 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E5691. (Unpublished study rece ived Jan 5, 1978 under 4581- 174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:232580-AV)

78606 Terrell, Y.; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E5701. (Unpublished study received Jan 5, 1978 under 4581- 174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:232580-BD)

78609 Terrell, Y; Parke, G.S.E. (1977) Report on Oral LD50 in Rats: Laboratory No. 7E5676. (Unpublished study rec eived Jan 5, 1978 under 4581- 174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:232580-BG)

113972 Latven, A. (1971) Accelerate: Summary--Acute Oral Toxicity in Starved Rats: LD50 = 650 MG/KG (0.57 ML/KG). (Un published study received Nov 29, 1971 under 4581

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114491 Latven, A. (1971) Accelerate: Summary--Acute Oral Toxicity in Starved Rats: LD50 = 650 Mg/Kg (0.57 Ml/Kg). (Unpublished study received Jul 9, 1975 under 1F1105; prepared by Pharmacology Research, Inc., submitted by Pennwalt Corp., Tacoma, WA; CDL: 094702-D)

42774001 Mallory, V. (1993) Acute Exposure Oral Toxicity in Rats with Hydrothol 191 (Endothall): Lab Project Number: PH 402 -ANA-002- 92. Unpublished study prepared by Pharmakon Research International, Inc. 169 p.

### 79 43242301 Mallory, V. (1994) Acute Exposure Oral Toxicity with Accelerate: Lab Project Number: PH 402 -ANA-003-93 . Unpublished study prepared by Pharmakon Research International, Inc. 170 p.

36561 Wise, M.T. (1977) Acute Inhalation Toxicity of a) Aquathol® K (N.B. 77-100-4) b) Hydrothol® 191 Liquid (N.B. 77 -100-2) c) Hydrothol® 47 Liquid (N.B. 77-100- 3) d) Aquatho l® (N.B. 77-99-7) e) Des-I-Cate® Accelerate (N.B. 77-99-6) f) Knox- Out® 2 FM (N.B. 4414 -94): Laboratory Nos. a) 7E-5660 b) 7E-5665 c) 7E-5670 d) 7E- 5675 e) 7E -5680 f) 7E- 5685. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096704-AO)

36592 Zeigler, R.L. (1977) Acute Inhalation Toxicity of 1. Aquathol® Granular (N.B. 77-99- 4) 2. Hydrothol® 191 Granular (N.B. 77 - 99-2) 3. Hydrothol® 47 Granular (N.B. 77- 99

- 3) 4. HydoutTM (N.B. 77 -99-5): Laboratory Nos. 1. 7E-5690 2. 7E-5695 3. 7E- 5700 4. 7E -5705. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-BU)

78202 Wise, M.T. (1977) Acute Inhalation Toxicity of Aquathol® K (N.B. 77-100-4); Hydrothol®191 Liquid (N.B. 77 -100-2); Hydrothol®47 Liquid (N.B. 77-100-3); Aquathol® (N.B. 77 -99-7); Des-i-cate®Accelerate (N.B. 77-99-6); Knox- out®2 FM (N.B. 4414 -94): Laboratory Nos. 7E-5660; 7E-5665; 7F-5670; 7E-5675; 7E- 5680; 7E5685. (Unpublished study received Jan 5, 1978 under 4581

- 174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL: 232580-AB)

78610 Zeigler, R.L. (1977) Acute Inhalation Toxicity of 1. Aquathol® Granular (N.B. 77 -99-4); 2. Hydrothol® 191 Granular (N.B. 77-99- 2); 3. Hydrothol® 47 Granular (N.B. 77 -99- 3); 4. HydoutTM (N.B. 77 -99-5): Laboratory Nos. 7E-5690; 7E- 5695; 7E -5700; 7E-5705. (Unpublished study received Jan 5, 1978 under 4581- 174; prepared by Cannon Laboratories, Inc., submitted by Pennwalt Corp., Philadelphia, Pa.; CDL:232580-BH)

42560901 Hoffman, G. (1992) An Acute Inhalation Toxicity Study of Hydrothol 191 in the Rat: Final Report: Lab Project Number: 91- 8356. Unpublished study prepared by Bio/dynamics, Inc. 126 p.

43152101 Trutter, J. (1993) Two-Generation Reproduction Study in Rats with Disodium Salt of Endothall: Final Report: Lab Project Number: 153/142. Unpublished study prepared by Hazleton Washington, Inc. 1479 p.

43629301 Trutter, J. (1995) Two-Generation Reproduction Study in Rats with Disodium Salt of Endothall: Addendum to MRID 43152101: Lab Project Number: 153

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101734 Pennwalt Corp. (1954) Full Reports of Investigations Made with Respect to the Safety of the Product: Disodium Endothall. (Unpublished study received Oct 30, 1963 under 4581-284; CDL: 007455-C)

44127801 Hoberg, J. (1993) Hydrothol 191--Determination of Effects on Seed Germination of Ten Plant Species: Summary Report: Lab Project Number: 93- 9- 4942: 12442.0593.6159.610: 050892. Unpublished study prepared by Springborn Labs., Inc. 56 p.

### 80 44127802 Hoberg, J. (1994) Hydrothol 191--Toxicity to the Marine Diatom, Skeletonema costatum: Summary Report: Lab Project Number: 93 -11-5025: 12442.0593.6162.450: 040692. Unpublished study prepared by Springborn Labs., Inc. 33 p.

44127803 Hoberg, J. (1994) Hydrothol 191--Toxicity to the Freshwater Alga, Anabaena flos -aquae: Summary Report: Lab Project Number: 93-11-5023: 12442.0593.6163.420: 040692. Unpublished study prepared by Springborn Labs., Inc. 36 p.

44127804 Hoberg, J. (1994) Hydrothol 191--Toxicity to the Freshwater Alga, Selenastrum capricornutum: Summary Report: Lab Project Number: 93 -11-5022: 12442.0593.6160.430: 040692. Unpublished study prepared by Springborn Labs. Inc. 33 p.

44127805 Hoberg, J. (1994) Hydrothol 191--Toxicity to the Freshwater Diatom, Navicula pelliculosa: Summary Report: Lab Project Number: 93-11-5021: 12442.0593.6161.440: 040692. Unpublished study prepared by Springborn Labs., Inc. 33 p.

44127806 Hoberg, J. (1994) Hydrothol 191--Toxicity to Duckweed, Lemna gibba: Summary Report: Lab Project Number: 93 -11- 5024: 12442. 0593.6164.410: 040692. Unpublished study prepared by Springborn Labs., Inc. 32 p.

43870401 Hoberg, J. (1995) Hydrothol 191--Determination of Effects on Seedling Emergence and Vegetative Vigor of Ten Plant Species: Final Report: Lab Project Number: 12442.0195.6185.610: BR -94-20: 95-8- 6045. Unpublished study prepared by Springborn Labs, Inc. 339 p.

44127801 Hoberg, J. (1993) Hydrothol 191--Determination of Effects on Seed Germination of Ten Plant Species: Summary Report: Lab Project Number: 93- 9- 4942: 12442.0593.6159.610: 050892. Unpublished study prepared by Springborn Labs., Inc. 56 p.

44976701 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191: A 96-Hour Toxicity Test with the Marine Diatom (Skeletonema costatum): Final Report: Lab Project Number: 299A -104. Unpublished study prepared by Wildlife International , Ltd. 38 p. {OPPTS 850.5400}

44820102 Dionne, E.; Sharp, J.; Formella, T. (1999) Dipotassium Salt of Endothall: A Freshwater Fish and Shellfish Magnitude of Residues Study in a Static Aquatic System: Lab Project Number: KP -97- 14: 52897/171.4/FIFRA: EN1115.95. Unpublished study prepared by Elf Atochem and ABC Laboratories, Inc. 213 p. {OPPTS 860.1400}

47563701 York, D. (2008) Endothall Mono (N,N-Dimethyl Alkylamine) Salt - Life-Cycle Toxicity Test with Mysids (Americamysis bahia). Project Number: 13845/6109, 051507/OPPTS/FIFRA/ MYSID/FLC. Unpublished study prepared by Springborn Smithers Laboratories. 92 p.

47563702 York, D. (2008) Endothall Mono (N,N-Dimethyl Alkylamine) Salt - Early LifeStage Toxicity Test with Sheepshead Minnow (Cyprinodon variegatus). Project Number: 13845/6110, 062707/OPPTS/ELS/SHM. Unpublished study prepared by Springborn Smithers Laboratories. 69 p.

### 81 35244 Acc#232582 Vilkas, A.G. (1977) The Acute Toxicity of Hydrothol(®) 191 to the Fiddler Crab, Uca pugilator: UCES Project # 11506 -41- 05. (Unpublished study received Jan 5, 1978 under 1F1105; prepared by Union Carbide Corp., submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL:096705-I)

71147 U.S. Department of Interior, Bureau of Reclamation (1963) Results of Algaecidal Evaluation Tests of Selected Compounds: Report No. WC -21. (Pages 26 -32 only, In Annual Progress Report of 1964 Lab. Studies; unpublished study; CDL:244131-U)

44949201 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 96- Hour Toxicity Test with the Freshwater Diatom (Navicula pelliculosa): Final Report: Lab Project Number: 299A -102. Unpublished study prepared by Wildlife International Ltd. 38 p. {OPPTS 850.5400}

44949202 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 96- Hour Toxicity Test with the Freshwater Alga (Anabaena flos

- aquae): Final Report: Lab Project Number: 299A -101. Unpublished study prepared by Wildlife International Ltd. 36 p. {OPPTS 850.5400}

44949402 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 7- Day Toxicity Test with Duckweed (Lemna gibba G3): Final Report: Lab Project Number: 299A -105. Unpublished study prepared by Wildlife International Ltd. 34 p. {OPPTS 850.4400}

44949403 Drottar, K.; Martin, K.; Krueger, H. (1999) Hydrothol 191 (Endothall): A 7- Day Toxicity Test with The Freshwater Alga (Selenastrum capricornutum): Final Report: Lab Project Number: 299A- 103. Unpublished study prepared by Wildlife International Ltd. 36 p. {OPPTS 850.5400}.

47742801 Picard, C. (2008) Endothall Mono (N,N-Dimethyl Alkylamine) Salt- Life-Cycle Toxicity Test Exposing Midges (Chir onomus tentans) to a Test Substance Applied to Sediment Under Static -Renewal Conditions Following EPA Test Methods. Project Number: 13845/6113, 031907/EPA/MIDGE/CHRONIC. Unpublished study prepared by Springborn Smithers Laboratories. 118 p.

47742802 Picard, C. (2009) Endothall Mono (N,N-Dimethyl Alkylamine) Salt- 28-Day Toxicity Test Exposing Estuarine Amphipods (Leptocheirus plumulosus) to a Test Substance Applied to Sediment Following EPA Test Methods. Project Number: 13845/6114, 031907/EPA/28D/LEPTOCHEIRUS. Unpublished study prepared by Springborn Smithers Laboratories. 79 p.

44820104 Giddings, J. (1999) Ecological Risk Assessment of Aquatic Herbicides Containing Endothall: Final Report: Lab Project Number: KP -98-31: 98-11-7564: 12442-0898- 6271- 251. Unpublished study prepared by Elf Atochem and Springborn Laboratories, Inc. 64 p.

36539 Miller, H. (1975) Phytotoxicity: Phototoxicity to Irrigated Crops. (Unpublished study received Jan 5, 1978 under 1F1105; submitted by Pennwalt Corp., Agchem Div., King of Prussia, Pa.; CDL: 096704-N)

35245 Pennwalt Corporation (1970) Beneficial Insect Safety. (Unpublished study received Jan 5, 1978 under 1F1105; CDL:096705-K)

40986 Bowles, E.J.; Keckemet, O; Boyle, W.D.; et al. (1964) Hydrothol 191 as an Aquatic Herbicide in Flowing Water. (Unpublished study received Apr 10,

### 82 1966 under 6G0503; submitted by Pennsalt Chemical Corp., Bryan, Tex.; CDL:090587-AE)

55700 Frank, P.A.; Comes, R.D. (1967) Herbicidal residues in pond water and hydrosoil. Weeds 15(3):210

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56395 Hestand, R.S., III; Carter, C.C. (1967?) Herbicide Effects on Aquatic Plants. (Unpublished study received Dec 19, 1975 under 6H5112; submitted by 3M Co., St. Paul, Minn.; CDL:230414-C)

56396 Hestand, R.S., III; Carter, C.C. (1968?) Herbicide Effects on Phytoplankton. (Unpublished study received Dec 19, 1975 under 6H5112; submitted by 3M Co., St. Paul, Minn.; CDL:230414-D)

74229 U.S. Department of the Interior, Bureau of Reclamation (1964) Results of Algaecidal Evaluation Tests of Selected Compounds: Report No. WC

- 21. (Unpublished study; CDL:244122-U)

101733 Pennwalt Corp. (1966) Efficacy of Accelerate, Desicate and Other Compounds for Defoliation of Cotton|. (Compilation; unpublished study received on unknown date under 4581-284; CDL:007455-B)

114517 Bowles, E.; Keckemet, J.; Boyle, W.; et al. (1965) Hydrothol 191 as an Aquatic Herbicide in Flowing Water. (Unpublished study received Mar 15, 1966 under 4581 -139; submitted by Agchem Div., Pennwalt Corp., Philadelphia, PA; CDL:007441-Q)

114492 Pennwalt Corp. (1972) Responses of Plankton and Macrofauna Communities To Test Application of Chemical Herbicides. (Unpublished study received Jul 9, 1975 under 1F1105; CDL:094702-H)

ACC 244122 The Acute Toxicity of Hydout to Mussel (Mytilus edulis) embryos. Prepared by SRI International, Menlo Park, CA, June 20, 1980. Exhibit 30 in Fish and Wildlife Safety Section IX for Hydout (acc#244122).

ACC 094509 Linn, J.D. (1967). Experiments on the Effects of Field Application of Hydrothol 191 on Fish. 17 p. Study conducted by California Department of Game and Fish. Submitted by Pennwalt Corp., Pet. #1F1105, Acc # 094509 (exhibit C-99), 12/1/70. Test ID # ES-BB3.

ACC 094509 Swabey, Y.H. and C.F. Schneck. (1963). Algicides and Aquatic Herbicides. 22 p. Study conducted by Ontario Water Resources Commission. Submitted by Pennwalt Corp., Pet. #1F1105, Acc # 094509 (exhibit C

- 61), 12/1/70. Test ID # ES-F4.

ACC 094509 McCraren, J.P. (undated). Some chronic effects of Hydrothol 191 on Redear Sunfish in two diverse aquatic environments. 38 p. Study conducted by USDI at Tishomongo National Fish Hatchery, Oklahoma in 1966. Submitted by Pennwalt Corp., Pet. #1F1105, Acc# 094509 (exhibit C-72), 12/01/70. Test ID # ES-BB4.

96295 Walker, C.R. (1963) Letter sent to Harold L. Lindaberry dated Nov 8, 1963 Fish toxicity studies|. (U.S. Fish and Wildlife Service, Fish Control Laboratory; unpublished study; CDL:090719-G)

### 83 114493 Walker, C. (1971) The toxicological effects of herbicides and weed control on fish and other organisms in the aquatic ecosystem. By U.S. Fish and Wildlife Service, Div. of Fishery Research, Branch of Pest Control Research. Pages 119

- 126, In Proc. Eur. Weed Res. Coun. 3rd Int. Symp. Aquatic Weeds; 1971. S.l.: s.n. (Also In unpublished submission received Jul 9, 1975 under 1F1105; submitted by Pennwalt Corp., Tacoma, WA; CDL: 094702-I)

E012941 MRID 49660201 Keller, A. E., Dutton, R. J., Bitton, G., and Crisman, T. L. 1988. Chronic Toxicity of Hydrothol 191 to Ceriodaphnia dubia at 25 and 15 Degrees C. Bull. Environ. Contam. Toxicol. 41[2], 233-240.

### 84 

## APPENDIX A. SLUA Summary Table for Endothall

Date: December 31, 2014 Screening Level Estimates of Agricultural Uses of Endothall Case (002245)

Sorted Alphabetically Reporting Years: 2004-2012

Average Percent Crop Treated Crop Lbs. A.I. Average Maximum 1 Alfalfa 3,000 < 1 < 2.5
2 Cotton 2,000 < 1 < 2.5
3 Potatoes 4,000 < 2.5 < 2.5

All numbers are rounded. <2.5: less than 2.5 percent of crop is treated. <1: less than 1 percent of crop is treated.

SLUA data sources include: USDA-NASS (United States Department of Agriculture's National Agricultural Statistics Service) Private Pesticide Market Research California DPR (Department of Pesticide Regulation) These results reflect amalgamated data developed by the Agency and are releasable to the public.85APPENDIX B. Endothall IncidentsA search for ecological incidents related to endothall use, (looking underallPC codes related to endothall; endothall acid, disodiumdipotassium and mono (N,N-dimethylalkylamine) salts of endothall; 038901, 038903, 038904 and 038905, respectively) conducted onApril 7, 2015; yielded three (3) incidents; two (2) involving aquatic animals and one (1) terrestrial plants listed under endothall acid (PCcode 038901); and two (2) incidents; one (1) involving aquatic animals and one (1) terrestrial plants, under the mono (N,Ndimethylalkylamine) salt of endothall (PC code 038905). There were no incidents were listed for either the disodium or dipotassiumsalts of endothall (PC codes 038903 and 038904, respectively); all of this is summarized below.Table B-1. Endothall Incidents, as Reported in the EIIS DatabaseIncidentID #State,CountyMagnitudeYearDescriptionLegalityCertaintyI015726-001Hernando, FLUnknown2004To comply with 6(a)2 requirements, Cerexagri reported an incident in LakeTarpon, FL, when the Southwest Florida Water Management District sprayedthe lake as part of its program to rid the lake of hydrilla. The herbicide usedwas Aquathol Super K (endothall–dipotassium salt) and the targetedconcentration was 2.5 ppm; 47 acres were treated @ 55 lbs/acre. Theherbicide was applied on September 28/29 and, by October 3, dead musselswere reported floating on the surface. There were no analyses included. Tocomply with 6(a)2 requirements, DuPont reported a claim from a landownerin western Kentucky that, for two years in a row, an application of DuPontOust XP Herbicide plus Diuron to an area around a utility substation resultedin runoff that damaged his corn crop. The landowner had a soil test madewhich found traces of Diuron. No symptoms of the affected crop were given.UnknownPossibleB0000-231-03Butte,CA1000 fish(mostly carp)1971A 5-gallon can of Hydrothol 191 (endothall–mono salt) was found drippingin a drain near Richvale on Sept. 7, 1971. Over 1000 fish were killed, mostlycarp (Cyprinus carpio). No tissue analyses were made and the wardeninvestigating the incident did not file a complaint. No analytical data weregiven but the supposition is that a dripping Hydrothol 191 can wasresponsible for the fish kill.Misuse(Accidental)HighlyProbableI013884-031Grant,WANot given1998This is from the 1999 Annual Report from the Washington State Departmentof Health Pesticide Incident Reporting and Tracking Review Panel,November 2000, from the 1998 PIRT Data. Plane spraying on potato fielddrifted on to alfalfa (Medicago sativa). Observed Diquat injury to alfalfa. Noinformation supplied regarding endothall related damage resulting from spraydrift.RegisteredUsePossible86IncidentID #State,CountyMagnitudeYearDescriptionLegalityCertaintyI010688-001MN75,0002000To comply with 6(a)2 regulations, Elf Atochem reported a fish kill in thecooling water effluent of the North States Power's Prairie Island NuclearGenerating Station on August 16, 2000. The information sent by ElfAtochem had been supplied by Nalco Chemical Co. (Naperville, IL) whichhad conducted a mission to kill the zebra mussels infesting the coolingchambers of the power plant. The product used was EVAC biocide (EPARegistration No. 4581-380, Shaughnessy No. 038905) which is a dimethylcocoamine salt of endothall. Typically, the product is highly diluted withinshort distances of the application site to levels far below the LC50s for nontarget organisms. A potential factor, also, is the water temperature; in theprevious year's treatment, the water temperature was 84.2qFand there wereno fish kills but in the year 2000 the water temperature was 92qF. ElfAtochem feels that the concentration of EVAC applied was too high and thewater temperature was too high. Another factor was that the screens designedto prevent the entry of fish from the Mississippi River allow small fish toenter but as their growth progresses they have no way to leave the system andthus are killed by the pesticide in the cooling water effluent. Thousands ofcatfish (Ictaluridae), Green sunfish (Lepomis cyanellus), and shiner(Cyprinidae) were killed. Concentrations in the water ranged from 7.57-9.94ppb (mono (N,N- dimethylcocoamine salt of endothall).Misuse(Accidental)ProbableI014385-001WV2 birds2003This is from the Cerexagrl Aggregate Report for June 1, 2003 to August 31,2003. A remote 200 acre pond used to cool water used in a mining operation.Application was made to the pond and one Egret (Arteidae) was found dead 3days later and 1 dead Pelican (Pelecansussp.) was found 7 days later.Chemical analysis on the birds or the pond were not reported. Chemicalanalysis was not performed on the birds or water. Hydrothol 191 was theproduct that was used; and it was a water soluble packet.RegisteredUsePossibleUncertainties Related to the Use of Incident Information from the Ecological Incident Information SystemIncident data are used in risk assessments to provide evidence that the risk predictions from the screening level assessment are supportedby actual effects in the field. Incident reports submitted to EPA since approximately 1994 have been tracked by assignment ofincidentnumbers in an Incident Data System (IDS), microfiched, and then entered to a second database, the Ecological Incident InformationSystem (EIIS). Additionally, there is an on-going effort to enter information to EIIS on incident reports received prior to establishmentof current databases. Incident reports are not received in a consistent format (e.g., states and various labs usually have their own87formats), may involve multiple incidents involving multiple chemicals in one report, and may report on only part of a given incidentinvestigation (e.g., residues).Incidents entered into EIIS are categorized into one of several certainty levels regarding the likelihood that a particular pesticide isassociated with the incident: highly probable, probable, possible, unlikely, or unrelated. In brief, “highly probable” incidents usuallyrequire carcass residues and/or clear circumstances regarding the exposure. “Probable” incidents include those where residues were notavailable and/or circumstances were less clear than for “highly probable.” “Possible” incidents include those where multiplechemicalsmay have been involved and it is not clear what the contribution was of a given chemical. The “unlikely” category is used, for example,where a given chemical is practically nontoxic to the category of organism killed and/or the chemical was tested for but not detected insamples. “Unrelated” incidents are those that have been confirmed to be not pesticide-related.Incidents entered into the EIIS are also categorized as to use/misuse. Unless specifically confirmed by a state or federal agency to bemisuse, or there was very clear misuse such as intentional baiting to kill wildlife, incidents are not typically considered misuse.The number of documented kills in EIIS is believed to be a small fraction of total mortality caused by pesticides. Mortality incidentsmust be seen, reported, investigated, and have investigation reports submitted to EPA to have the potential for entry into thedatabase.Incidents often are not seen, due to scavenger removal of carcasses, decay in the field, or simply because carcasses may be hard to see onmany sites and/or few people are systematically looking. Poisoned animals may also move off-site to less conspicuous areas beforedying. Incidents may not get reported to appropriate authorities capable of investigating the incident for a variety of reasons includingthe finder may not know of the importance of reporting incidents, may not know who to call, may not feel they have the time ordesire tocall, or may hesitate to call because of their own involvement in the kill. Incidents reported may not get investigated if resources arelimited or may not get investigated thoroughly, with residue analyses, for example. Also, if kills are not reported and investigatedpromptly, there will be little chance of documenting the cause, since tissues and residues may deteriorate quickly. Reports ofinvestigated incidents often do not get submitted to EPA, since reporting by states is voluntary.Furthermore, the database relies heavily on registrant-submitted incident reports, and registrants are currently only requiredto submitdetailed information on ‘major’ ecological incidents, while ‘minor’ incidents are reported aggregately.Based on the40 CFR (§159.184 Toxic or adverse effect incident reports), an ecological incident is considered ‘major’ if any of thefollowing criteria are met:Fish or wildlife:(A) Involves any incident caused by a pesticide currently in Formal Review 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.88(C) Birds: Affected 200 or more individuals of a flocking species, or 50 or more individuals of a songbird species, or 5 or moreindividuals of a predatory species.(D) Mammals, reptiles, amphibians: Affected 50 or more individuals of a relatively common or herding species or 5 or moreindividuals 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 10acres,terrestrial or aquatic).Plants:(A) The effect is alleged to have occurred on more than 45 percent of the acreage exposed to the pesticide.All other ecological incidents are considered ‘minor’ and only need to be aggregately reported. ‘Minor’ incidents reported by theregistrants are not included in the EIIS database. Therefore, for example, an incident could affect 900 fish, 150 birds, 45 mammals, and40% of an exposed crop and not be included in the EIIS database [unless is it reported by a non-registrant (e.g., an incident submitted bya state agency–which are not systematically collected)]. Therefore, because the number of documented kills in EIIS is believed to be asmall fraction of total mortality caused by pesticides, absence of reports does not necessarily provide evidence of an absenceof incidents.In addition to the incidents recorded in EIIS and AIMS, additional incidents have been reported to the Agency in aggregated incidentreports. Pesticide registrants report certain types of incidents to the Agency as aggregate counts of incidents occurring perproduct perquarter. 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 otherterrestrial invertebrates. For endothall, registrants have reported one minor fish and wildlife incident for dipotassium saltof endothall,and three minor fish and wildlife incidents and one minor plant incident for the mono (N,N-dimethylalkylamine) salt of endothall.Unless additional information on these aggregated incidents become available, they will be assumed to be representative of registereduses of endothall in the risk assessment.

### 89 

## APPENDIX C. SIP & STIR Inputs and Outputs for Endothall Acid, and the dipotassium and mono (N,N-dimethylalkylamine) salts of endothall SIP Inputs/Outputs Table 1. Inputs Parameter Value Chemical name Endothall Acid (as ae) Solubility (in water at 25 o C; mg/L) 11000000

Mammalian LD 50 (mg/kg-bw) 44.4 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species Mammalian NOAEL (mg/kg-bw) 9.4 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg-bw) 229 Avian test species mallard duck Body weight (g) of "other" avian species Mineau scaling factor 1.15 Mallard NOAEC (mg/kg-diet) 50 Bobwhite quail NOAEC (mg/kg-diet) 0 NOAEC (mg/kg-diet) for other bird species Body weight (g) of other avian species NOAEC (mg/kg-diet) for 2nd other bird species Body weight (g) of 2nd other avian species

Table 2. Mammalian Results Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 1892000 1892000 Adjusted toxicity value (mg/kg-bw) 34.2 7.23 Ratio of exposure to toxicity 55401 261683

Conclusion* Exposure through drinking water alone is a potential

concern for mammals Exposure through drinking water alone is a potential

concern for mammals

Table 3. Avian Results Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 8910000 8910000 Adjusted toxicity value (mg/kg-bw) 119 2.48 Ratio of exposure to acute toxicity 74935 3591832

Conclusion* Exposure through drinking water alone is a potential concern for birds Exposure through drinking water alone is a potential concern for birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non-target animals.

### 90 Table 1. Inputs Parameter Value

Chemical name Endothall (dipotassium salt as ae) Solubility (in water at 25 o C; mg/L) 65000000

Mammalian LD 50 (mg/kg-bw) 24.3 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species Mammalian NOAEL (mg/kg-bw) 9.4 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg-bw) 61.6 Avian test species mallard duck Body weight (g) of "other" avian species Mineau scaling factor 1.15 Mallard NOAEC (mg/kg-diet) 0 Bobwhite quail NOAEC (mg/kg-diet) 0 NOAEC (mg/kg-diet) for other bird species Body weight (g) of other avian species NOAEC (mg/kg-diet) for 2nd other bird species Body weight (g) of 2nd other avian species

Table 2. Mammalian Results Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 11180000.0000 11180000.0000 Adjusted toxicity value (mg/kg-bw) 18.6906 7.2301 Ratio of exposure to toxicity 598161.5856 1546311.3330

Conclusion* Exposure through drinking water alone is a potential

concern for mammals Exposure through drinking water alone is a potential

concern for mammals

Table 3. Avian Results Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 52650000.0000 52650000.0000 Adjusted toxicity value (mg/kg-bw) 31.9843 0.0000 Ratio of exposure to acute toxicity 1646120.8927 0.0000

Conclusion* Exposure through drinking water alone is a potential concern for birds Due to insufficient data, risk cannot be precluded

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non-target animals.

### 91 Table 1. Inputs Parameter Value Chemical name Endothall (mono salt as ae) Solubility (in water at 25 o C; mg/L) 50000000

Mammalian LD 50 (mg/kg-bw) 49.1 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species Mammalian NOAEL (mg/kg-bw) 9.4 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg-bw) 91 Avian test species mallard duck Body weight (g) of "other" avian species Mineau scaling factor 1.15 Mallard NOAEC (mg/kg-diet) 82.4 Bobwhite quail NOAEC (mg/kg-diet) 613 NOAEC (mg/kg-diet) for other bird species Body weight (g) of other avian species NOAEC (mg/kg-diet) for 2nd other bird species Body weight (g) of 2nd other avian species

Table 2. Mammalian Results Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 8600000.0000 8600000.0000 Adjusted toxicity value (mg/kg-bw) 37.7658 7.2301 Ratio of exposure to toxicity 227719.3566 1189470.2561

Conclusion* Exposure through drinking water alone is a potential

concern for mammals Exposure through drinking water alone is a potential

concern for mammals

Table 3. Avian Results Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 40500000.0000 40500000.0000 Adjusted toxicity value (mg/kg-bw) 47.2495 4.0881 Ratio of exposure to acute toxicity 857151.7074 9906862.8392

Conclusion* Exposure through drinking water alone is a potential concern for birds Exposure through drinking water alone is a potential concern for birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non-target animals.

### 92 STIR Inputs/Outputs



### Input

Application and Chemical Information
Enter Chemical Name Endothall Acid Enter Chemical Use cotton Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) air Enter Chemical Molecular Weight (g/mole) 186.2 Enter Chemical Vapor Pressure (mmHg) 3.92E-05 Enter Application Rate (lb a.i./acre) 0.2859

Toxicity Properties

Bird Enter Lowest Bird Oral LD 50 (mg/kg bw) 229 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 1.58 Mammal Enter Lowest Rat Oral LD 50 (mg/kg bw) 44.4 Enter Lowest Rat Inhalation LC 50 (mg/L) 1.27 Duration of Rat Inhalation Study (hrs) 4 Enter Rat Weight (kg) 0.35


### Output Results Avian (0.020 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 3.93E-01 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 4.94E-02 Adjusted Inhalation LD 50 2.63E+01 Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.88E-03 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 2.75E-02 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 1.04E-03 Exposure not Likely Significant

Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 3.93E-01 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 6.21E-02 Adjusted Inhalation LD 50 7.56E+01 Ratio of Vapor Dose to Adjusted Inhalation LD 50 8.21E-04 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 3.45E-02 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 4.57E-04 Exposure not Likely Significant **NOTE**: When entering values, pres in order to update linked cells.

### 93 

### Input

Application and Chemical Information
Enter Chemical Name Dipotas Salt(as ae) Enter Chemical Use apples Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) air Enter Chemical Molecular Weight (g/mole) 262.31 Enter Chemical Vapor Pressure (mmHg) 3.92E-05 Enter Application Rate (lb a.i./acre) 0.3

Toxicity Properties

Bird Enter Lowest Bird Oral LD 50 (mg/kg bw) 61.6 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 1.58 Mammal Enter Lowest Rat Oral LD 50 (mg/kg bw) 24.3 Enter Lowest Rat Inhalation LC 50 (mg/L) 0.53 Duration of Rat Inhalation Study (hrs) 4 Enter Rat Weight (kg) 0.35


### Output Results Avian (0.020 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 5.53E-01 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 6.96E-02 Adjusted Inhalation LD 50 5.40E+00 Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.29E-02 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 2.88E-02 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 5.34E-03 Exposure not Likely Significant

Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 5.53E-01 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 8.74E-02 Adjusted Inhalation LD 50 3.16E+01 Ratio of Vapor Dose to Adjusted Inhalation LD 50 2.77E-03 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 3.62E-02 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 1.15E-03 Exposure not Likely Significant **NOTE**: When entering values, pres in order to update linked cells.

### 94 

## Input

Application and Chemical Information
Enter Chemical Name Mono Salt (as ae) Enter Chemical Use potato Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) air Enter Chemical Molecular Weight (g/mole) 228.109779 Enter Chemical Vapor Pressure (mmHg) 2.09E-05 Enter Application Rate (lb a.i./acre) 2.3

Toxicity Properties

Bird Enter Lowest Bird Oral LD 50 (mg/kg bw) 91 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 1.58 Mammal Enter Lowest Rat Oral LD 50 (mg/kg bw) 49.1 Enter Lowest Rat Inhalation LC 50 (mg/L) 0.5 Duration of Rat Inhalation Study (hrs) 4 Enter Rat Weight (kg) 0.35


## Output Results Avian (0.020 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 2.57E-01 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.23E-02 Adjusted Inhalation LD 50 3.72E+00 Ratio of Vapor Dose to Adjusted Inhalation LD 50 8.66E-03 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 2.21E-01 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 5.93E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 2.57E-01 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 4.05E-02 Adjusted Inhalation LD 50 2.98E+01 Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.36E-03 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 2.78E-01 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 9.33E-03 Exposure not Likely Significant **NOTE**: When entering values, pres in order to update linked cells.