2 

 

Preliminary Problem Formulation for the 

Environmental Fate and Ecological Risk, Endangered 

Species, and Drinking Water Assessments in Support 

of the Registration Review of Starlicide 

(3-chloro-p-toluidine hydrochloride) 

(CAS 7745-89-3) 

Prepared by:

Christine Hartless, Wildlife Biologist

R. David Jones, Senior Fate Scientist

Christina DeMariano, Biologist

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch II

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

Brian Anderson, Branch Chief

September 1, 2011 

NH2

Cl
3 

Table of Contents 

1. Purpose ....................................................................................................................................... 4

2. Nature of Regulatory Action ...................................................................................................... 4

3. Conclusions from Previous Risk Assessments .......................................................................... 4

4. Stressor Source and Distribution ................................................................................................ 6

4.1. Mechanism of Action .......................................................................................................... 6

4.2. Overview of Pesticide Usage .............................................................................................. 6

4.3. Environmental Fate and Transport ..................................................................................... 10

5. Receptors.................................................................................................................................. 13

5.1. Effects to Aquatic Organisms ........................................................................................... 14

5.2. Effects to Terrestrial Organisms ....................................................................................... 14

5.3. Degradate toxicity ............................................................................................................. 14

5.4. Ecological Incidents ........................................................................................................... 15

6. Ecosystems Potentially at Risk .............................................................................................. 15

7. Assessment Endpoints ............................................................................................................. 15

8. Conceptual Model ..................................................................................................................... 15

8.1. Risk Hypothesis ................................................................................................................. 16

8.2. Conceptual Diagram .......................................................................................................... 16

9. Analysis Plan ............................................................................................................................ 19

9.1. Stressors of Concern ......................................................................................................... 19

9.2. Measures of Exposure ....................................................................................................... 19

9.3. Measures of Effect ............................................................................................................ 21

9.4. Integration of Exposure and Effects ................................................................................. 22

9.5. Endangered Species Assessments ..................................................................................... 22

9.6. Drinking Water Assessment ............................................................................................. 23

10. Endocrine Disruptor Screening Program ........................................................................... 23

11. Preliminary Identification of Data Gaps ................................................................................ 24

11.1. Fate .................................................................................................................................. 24

11.2. Effects ............................................................................................................................. 27

12. References .............................................................................................................................. 31

Attachment 1: Non-guideline Study DCI Justifications ............................................................... 34
4 

1. Purpose 

The purpose of this problem formulation is to provide an understanding of the environmental fate 

and ecological effects of the registered uses of starlicide (3-chloro-p-toluidine 

hydrochloride). Starlicide is an avicide used to control ravens, starlings, crows, pigeons, 

cowbirds, grackles, blackbirds, magpies, and certain gull species. It is slow-acting and highly 

toxic to target species, with death occurring 1-3 days after ingestion. Use sites vary by species 

but include livestock and poultry feedlots, buildings and fenced non-crop areas, Federal and 

State wildlife refuges and protected areas, gull colonies in coastal areas, and bird staging areas 

and roosting sites. 

 

This document will provide a plan for analyzing data relevant to starlicide and for conducting 

environmental fate and ecological risk, endangered species, and drinking water assessments for 

its registered uses. Additionally, this problem formulation is intended to identify data gaps, 

uncertainties, and potential assumptions used to address those uncertainties, relative to 

characterizing the ecological risk associated with the registered uses of starlicide. 

2. Nature of Regulatory Action 

The Food Quality Protection Act of 1996 mandated the Environmental Protection Agency (EPA) 

to implement a new program for assessing the risks of pesticides, i.e., registration review 

(http://www.epa.gov/oppsrrd1/registration_review/). All pesticides distributed or sold in the 

United States generally must be registered by EPA. The decision to register a pesticide is based 

on the consideration of scientific data and other factors showing that it will not cause 

unreasonable risks to human health, workers, or the environment when used as directed on 

product labeling. The registration review program is intended to ensure that, as the ability to 

assess risk evolves and as policies and practices change, all registered pesticides continue to 

meet the statutory standard of no unreasonable adverse effects to human health and the 

environment. Changes in science, public policy, and pesticide use practices will occur over time. 

Through the new registration review program, the Agency periodically reevaluates pesticides to 

ensure that as change occurs, products in the marketplace can be used safely. 

As part of the implementation of the new Registration Review program pursuant to Section 3(g) 

of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is beginning its 

evaluation to determine whether starlicide continues to meet the FIFRA standard for registration. 

This problem formulation for the environmental fate and ecological risk assessment chapter in 

support of the registration review is intended for the initial docket opening the public phase of 

the review process. 

3. Conclusions from Previous Risk Assessments 

The Agency has conducted previous ecological risk assessments on starlicide that serve as a 

basis for this problem formulation. These are briefly summarized below. 
5 

The starlicide RED was completed in 1995. Environmental risk conclusions included non-target 

birds and mammals that may be at risk from eating starlicide treated bait (primary exposure), or, 

as scavengers and predators, from consuming animals who have eaten treated baits (secondary 

exposure). The risk to primary non-target bird populations was considered high for all uses of 

starlicide, as was the risk to endangered small mammals in areas treated with the highest 

application rates. In addition, starlicide also posed acute risks to aquatic invertebrates. Based on 

the environmental and human health risk conclusions, the Agency required risk reduction 

measures to mitigate mixer/loader and ecological risk. These included lowering the application 

rates on all broadcast applications, which were as high as 0.5 lb a.i./acre, to 0.1 lb a.i./acre, 

requiring pre-baiting to ensure rapid bait acceptance by target species, and restricting the use of 

treated baits to at least 50 ft. from bodies of water. In addition, because of its potential high risk 

to non-target mammals and birds, the only remaining starlicide end-use product which was 

classified for general use, was changed to restricted use. The Agency also required a respirator 

for mixers/loaders of packages containing one pound or more of starlicide concentrate, because 

of its presumed high acute inhalation toxicity. No ecological toxicity or fate data were requested 

as a result of the RED. 

The RED mitigations that addressed ecological risk concerns have been implemented on a 

majority of the labels. All labels are classified as restricted use and have application rates of ≤0.1 

lbs a.i./acre/application. The majority of the labels clearly require treated baits to be used at least 

50 ft. from bodies of water and require pre-baiting. Those labels that do not have these 

statements are listed below: 

 EPA Reg. No. 67517-8 (Starlicide Complete) 

o Does not include a statement required placing baits at least 50 ft. from water 

bodies. 

o Language on label regarding prebaiting is: “Prebaiting with non-toxic pellets may 

be necessary to achieve desired results.” 

 EPA Reg. No. 56228-29 (Compound DRC-1339 Concentrate – livestock, nest and fodder 

depredations) 

o Language on label regarding proximity to water: “DO NOT apply baits within 50 

feet of permanent manmade or natural bodies of water, unless baited sites are 

under constant observation while baits are exposed.” 

 EPA SLN No. TX060016 (Compound DRC-1339 Concentrate – egg depredation of 

federal and/or state-designated T&E species – TX) Parent label is EPA Reg. No. 56228-

29. 

o Does not include a statement required placing baits at least 50 ft. from water 

bodies. 

o Parent label language is: “DO NOT apply baits within 50 feet of permanent 

manmade or natural bodies of water, unless baited sites are under constant 

observation while baits are exposed.” 

Since the RED was completed, EFED has conducted several risk assessments for new uses of 

starlicide through Section 3s, Section 24Cs, and Section 18s. Risk concerns were similar to those 

outlined in the RED; a complete list of all currently stamped labels is presented in Section 4.2.
6 

4. Stressor Source and Distribution 

4.1. Mechanism of Action 

Starlicide is an aniline avicide. The primary mode of action of DRC-1339, following its ingestion 

by susceptible bird species appears to be that it causes irreversible necrosis of the kidney and the 

affected bird is subsequently unable to excrete uric acid. DRC-1339 itself is rapidly metabolized, 

excreted, and is apparently not accumulated in body tissues. Death usually occurs from uremia 1 

to 3 days after most of the DRC-1339 has left the body (Knittle et al. 1990). In less sensitive bird 

species and in mammal species, central nervous system depression and the attendant cardiac or 

pulmonary arrest is the cause of death (Schaefer 1984). 

4.2. Overview of Pesticide Usage 

Starlicide is labeled for use non-crop staging areas associated with roosts, peanut fields and 

pecan orchards, in and around feed and dairy lots, near target birds’ nests, industrial and 

commercial areas (e.g., utility poles, rooftops, and electrical lines), within fruit tree orchards, and 

in “decoy sunflower fields” (i.e., sunflowers planted in an alternative field to lure pest bird 

species from harvest). The Biological and Economic Analysis Division (BEAD) reported that no 

usage data were available for starlicide. 

Table 1 lists all national end-use product labels and Special Local Needs (SLN labels) with the 

associated application rates, methods of application, maximum rates, and target species. This use 

information will form the basis of the starlicide exposure estimation for the registration review 

risk assessment. Starlicide is a restricted use pesticide due to its potential high risk to non-target 

mammals and birds; its corrosiveness to eyes and skin; and presumed high acute inhalation 

toxicity. 

Only one product is formulated as pre-mixed bait pellets (EPA Reg. No. 67517-8, Starlicide 

Complete). All other starlicide products are formulated as a concentrate with directions on the 

label for preparing the baits. The directions will vary depending on the type of baits (e.g., rice, 

grains, dry dog food, cull French fries, fat nuggets, hard-boiled eggs, meat chunks, and 

watermelon) that are specified on the label. For the majority of the baits, starlicide is applied by 

dissolving or suspending the avicide in a solvent of water or oil and mixing the solution with 

bait. When the prepared bait appears coated, baits are dried before use. 

As a result of the RED mitigation, all labels should require a pre-baiting period (specified as 

applying non-treated bait 1 to 3 days before treatment at same application rate as treated bait). 

All labels except one (EPA Reg. No. 67517-8, Starlicide Complete) include this requirement. 

Pretreatment observations must include: feeding habits, preferred feeding location, daily activity 

patterns, and population of target species as well as relative abundance and types of non-target 

species at baiting sites. Treated bait may not be placed in areas where there is danger of 

consumption by Endangered or Threatened species. After the daily patterns of target species 

have been assessed, appropriate baiting locations can be selected. 

The table below is designed to provide a summary of the use sites, application rates, and target 
7 

species. It does not provide all the detailed information that is available on each label (e.g., types 

of bait for each label, mixing directions, secondary target pests (only applicable when mixed in 

flocks of the primary target pests), carcass and residual bait collection, and specific listed species 

protections). 

Table 1. Summary of Starlicide Labeled Uses as of March 23, 2011 

Use site State and 

EPA Reg 

No. 

Max. Single 

App. Rate 

(lb a.i./ acre) 

Max. No. 

Apps. 

Max. 

annual rate 

(lb a.i./acre) 

Application 

method of 

treated baitsb 

Target pest 

National labels

Beef cattle, 

dairy cattle, 

swine, and 

poultry 

feedlots 

56228-10 0.08 Not 

provided 

Not 

provided 

Manually place 

bait in stations, 

on the ground 

inside feedlots 

(with no 

animals 

present) or on 

the perimeter 

outside pen 

areas (if 

animals 

present) 

Brewer’s blackbird, 

Brown-headed 

cowbird, common 

grackle, red-winged 

blackbird, 

European starling 

Nesting 

colonies and 

feeding 

areas at 

airports, 

industrial 

sites, 

dumps, 

landfills, 

and noncrop areas. 

56228-17 0.1 10 1.0 a

 Hand broadcast 

treated bait 

Herring gull, great 

black-backed gull, 

ring-billed gull, 

laughing gull 

(except locations 

where laughing gull 

is protected), 

western gull, 

California gull 

Pigeons in 

and around 

structures 

and noncrop areas 

56228-28 0.05 Not 

provided 

Not 

provided 

Hand broadcast 

treated bait on 

rooftops, bait 

containers, or 

bare ground (in 

fenced areas) 

Feral pigeons 

(Columbia livia) 
8 

Table 1. Summary of Starlicide Labeled Uses as of March 23, 2011 

Use site State and 

EPA Reg 

No. 

Max. Single 

App. Rate 

(lb a.i./ acre) 

Max. No. 

Apps. 

Max. 

annual rate 

(lb a.i./acre) 

Application 

method of 

treated baitsb 

Target pest 

Pasture and 

rangeland, 

refuges and 

other areas, 

within 25 ft 

of silage/ 

fodder bags 

56228-29 0.083 Not 

provided 

Not 

provided 

Manual 

broadcast or 

placement in 

draw stations 

(fresh, 

unpoisoned 

carcass), 

dummy nests, 

or elevated 

wooden 

platforms 

Common raven, 

Chihuahuan raven, 

American crow, 

black-billed 

magpie, and fish 

crow. 

Non-crop 

staging 

areas 

associated 

with roosts 

56228-30 0.1 5 0.5 Feeding 

stations, 

mechanical 

broadcast, 

manual 

broadcast 

Boat-tailed grackle, 

brown-headed 

cowbird, common 

grackle, great-tailed 

grackle, red-winged 

blackbird, 

European starling 

Livestock 

feedlots and 

poultry 

operations 

67517-8 

(sold as a 

prepared 

bait, 0.1% 

a.i.) 

0.001 lb 

a.i./1000 linear 

feet 

Not 

provided 

0.02 lb 

a.i/acre for 

lots >10 

acres; 

0.05 lb 

a.i./acre for 

lots < 10 

acres 

Manual 

broadcast or 

feeding stations 

Starling, common 

grackle, brown 

headed cowbird, 

red-winged 

blackbird, Brewer’s 

blackbirds 

Special Local Need labels

Non-staging 

areas 

associated 

with roost, 

feedlots, 

non-crop 

areas, 

within fruit 

trees 

ID - 050013 

IN - 040001

IN - 080003

KY-020002

KY-020003 

NM-030003 

NV-020005 

TN-080003 

TN-080004 

WV-010002 

WV-040001 

WY-070002 

NE-100003 

0.1 5a

 0.5 Manual or 

mechanical 

broadcast, 

livestock, bait 

containers, 

elevated 

platforms 

American/Common 

crow, European 

starlings, common 

ravens, boat-tailed 

grackles, brownheaded cowbirds, 

common grackles, 

great tailed 

grackles, redwinged blackbirds 

rock doves and 

magpies 
9 

Table 1. Summary of Starlicide Labeled Uses as of March 23, 2011 

Use site State and 

EPA Reg 

No. 

Max. Single 

App. Rate 

(lb a.i./ acre) 

Max. No. 

Apps. 

Max. 

annual rate 

(lb a.i./acre) 

Application 

method of 

treated baitsb 

Target pest 

Non-staging 

areas 

associated 

with roost 

and pecan 

orchard 

MD-080005 

MS-050008 

OK-990001 

TX-020003 

WV-110001 

0.09 5a 0.5 Manual 

broadcast; bait 

station 

Common crow, fish 

crow, American 

crows, fish crows, 

Chihuahua ravens, 

common ravens 

Nonharvesting 

areas of 

ripening 

commercial 

and “decoy” 

sunflower 

fields 

SD-980005 0.038b Not 

reported 

Not reported Manual 

broadcast 

Red -winged black 

birds, yellowheaded black birds, 

Brewer's 

blackbirds, 

starlings, brownheaded cowbird 

and common 

grackles 

In and 

around 

feedlots and 

dairies 

ID-050014 0.08 5a 0.4 Manual 

broadcast; 

feeding station 

Common ravens, 

American crows, 

black-billed 

magpies and pigeon 

Federal 

listed 

feedlots 

TX-090010 0.08 N/A Not reported Not reported Control target 

species 

25 feet from 

listed areas; 

Dummy 

nest maybe 

constructed 

to house 

treated eggs 

NV-040004 0.083 1a 0.083 Manual 

broadcast 

Common ravens 

and white necked 

ravens 

“Decoy 

sunflowers 

fields” 

ND-920001 0.04 12a 0.5 Manual 

Broadcast 

Red -winged black 

birds, yellowheaded black birds, 

Brewer's 

blackbirds, 

European starlings, 

brown-headed 

cowbird and 

common grackles 

Staging 

areas 

associated 

with roost 

TX-890001 0.04 5a 0.2 Manual 

broadcast; bait 

station 

feral pigeons and 

roosting birds 

including starlings, 

common grackle, 

great-tailed grackle, 

brown headed 

cowbirds, and redwinged blackbirds 
10 

Table 1. Summary of Starlicide Labeled Uses as of March 23, 2011 

Use site State and 

EPA Reg 

No. 

Max. Single 

App. Rate 

(lb a.i./ acre) 

Max. No. 

Apps. 

Max. 

annual rate 

(lb a.i./acre) 

Application 

method of 

treated baitsb 

Target pest 

Applied to 

stubble 

fields, open 

grassy or 

bare 

grounds 

PA-050002 0.045 11a 0.5 Manual 

broadcast, bait 

dispenser 

Common crows, 

fish crows 

Bait stations 

at least 6 

feet high 

OR-010024 0.1 Not 

reported 

Not reported Manual 

placement on 

platform

Mag-pies 

Near target 

species nest 

TX-060016 0.000043 lb 

a.i. per hardboiled egg, 

maximum 18 

eggs per bait 

site 

Not 

reported 

Not reported Manual 

placement 

Common grackle, 

great-tailed 

grackles, boattailed grackle 

a

 EFED calculated. 

b

 Individual labels may allow a subset of these application methods

4.3. Environmental Fate and Transport 

Based on submitted data, starlicide (3-chloro-p-toluidine) is expected to degrade rapidly in the 

presence of sunlight and be moderately mobile in the environment. Registrant-submitted data 

defining the physical, chemical, fate and transport characteristics associated with starlicide are 

summarized in Table 2. The formation of degradates in an aerobic soil metabolism study 

suggests that this could also be a major route of dissipation, but the study is inadequate to 

quantify the rate of degradation. Starlicide is soluble in water (53.2 g/L) and has a relatively high 

Henry’s Law Constant, (1.47 x 10-8 atm·m3

·mol-1), so it is not expected to volatilize significantly 

in the environment. It has an estimated pKa of 3.9 for protonation of the amine group; 

consequently, in soils at pH values >4.8, over 90% of the starlicide will be in the free amine 

form, and in soils below pH 3, the ammonium ion form of starlicide will be the major species. 

No monitoring data are available for starlicide in the environment and field studies to 

characterize starlicide’s fate and transport have not been conducted. However, given starlicide’s 

use pattern is on baits for birds, it is likely that the major route of dissipation from the use site is 

consumption of the bait. Dissipation by the target species after consumption has not been 

characterized. 
11 

Table 2. General physico-chemical and environmental fate properties of starlicide.

Parameter Value Reference

Selected Physical/Chemical Parameters

Structure 

Molecular Weight 179.24 g·mol (salt) 

143.70 g·mol (cation only) 

calculated 

Water Solubility 53.2 g·L-1 at 30o C MRID 41609301 

Vapor pressure 1.06 x 10-4 torr at 25o C MRID 41609301 

Density 0.44 kg·L-1 MRID 41609301 

Henry's Law Constant 1.47 x 10-8 atm·m3·mol-1 calculated 

Octanol/Water Partition 

Coefficient (Kow) 0.022 estimated* 

pKa 3.9 MRID 41609301 

Hydrolysis t1/2 pH 5 

pH 7 

pH 9 

no evidence of degradation 

no evidence of degradation 

no evidence of degradation 

MRID 41760501 

Aqueous Photolysis t1⁄2 0.67 days MRID 42838801 

Batch Equilibrium (Kd) 

69 L·kg-1 – Menlo Park loam 

3.7 L·kg-1 - EPA 14 silty clay 

 7.0 L·kg-1 – EPA 12 clay 

3.7 L·kg-1 – ‘Ward’s’ sandy loam 

8.8 L·kg-1 - ‘Ward’s’ clay loam 

MRID 43284502 

Bioconcentration Factor 

Fish: 

150 in viscera 

33 in filet 

88 in whole body 

MRID 43069801 

* Kow estimated as the ratio of the solubilities in n-octanol and water at 30 oC. n-octanol solubility: 1.2 g·L-1

(MRID 41609301). 

There is no evidence that starlicide degrades in water through hydrolysis at environmentally 

significant pH's in a single study at 3 pHs run over thirty days, but starlicide does degrade 

rapidly by photolysis in water. In a 30 hour test at pH 7, starlicide degraded with a half-life of 

NH2

Cl
12 

1.25d in the test system, which would be equivalent 0.67 d in fall sunlight conditions. One 

degradate, 3-hydroxy-p-toluidine (HPT), was identified in the irradiated solution. HPT increased 

46.8% after 18 hours of irradiation (Table 3). A submitted aerobic soil metabolism study on a 

Kenyon loam provide some information on degradates formed by metabolism in soil but was 

inadequate for use in estimating degradation rates due to poor extraction. The degradate, Nacetyl-3-chloro-p-toluidine (ACPTH), was found at 10.2% of the initial concentration of parent 

in the test system at 24 h after the initiation of the test. 

Table 3. The maximum amount of degradates formed in laboratory fate 

studies by starlicide and the time when the maximum occurred.

Degradate Aqueous 

Photolysis 

Aerobic Soil 

Metabolism 

BCF 

CO2 12.8% @ 99 d

3-hydroxy-p-toluidine 67% @ 14d 

N-acetyl-3-chloro-p-toluidine 10.2% @ 1d max @ 28 d 

An acceptable batch equilibrium study has not been conducted for starlicide. Soil-water partition 

coefficient (Kd's) were estimated using a kinetics study at a single concentration, were 69, 3.7, 

7.0, 3.7, and 8.8 for the loam soil, two sandy loams, a silty clay, and a clay sediment, 

respectively (MRID 43284502). 

Starlicide residues accumulated only slightly in bluegill sunfish exposed to starlicide 

hydrochloride at 0.1 mg/L for 28 days under flow-through conditions. Average calculated 

bioconcentration factors were 33x, 150x, and 88x for edible tissues (muscle), inedible tissues 

(carcass and viscera), and whole fish, respectively. One major degradate, N-acetyl-3-chloro- 4-

methylaniline, was identified from fish (all tissue substrates) collected after 28 days of exposure. 

Depuration was relatively slow; after 28 days of depuration, 54.3% of the accumulated residues 

were eliminated from the edible tissues, 64.1% from the non-edible tissues, and 63.4% from the 

NH2

HO

NH

Cl
13 

whole fish (MRID 43069801) 

5. Receptors

Consistent with the process described in the Overview Document (USEPA 2004), the risk 

assessment for starlicide will rely on a surrogate species approach. Toxicological data generated 

from surrogate test species, which are intended to be representative of broad taxonomic groups, 

are used to extrapolate to potential effects on a variety of species (receptors) included under 

these taxonomic groupings. 

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the 

available open literature are used to evaluate the potential direct and indirect effects of starlicide 

on aquatic and terrestrial receptors. These include toxicity data on the technical grade active 

ingredient, degradates, and, when available, formulated products (e.g. “Six-Pack” studies). The 

open literature studies are identified using EPA’s ECOTOX database 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 starlicide on biotic communities from loss of species that are sensitive to the chemical and 

from changes in structure and functional characteristics of the affected communities. 

Table 4 provides a summary of the taxonomic groups and the surrogate species tested to 

characterize the potential acute and chronic ecological effects of starlicide. In addition, the table 

provides a preliminary overview of the potential acute toxicity of starlicide by providing the 

acute toxicity classifications. 

Table 4. Test Species Evaluated for Assessing Potential Ecological Effects of Starlicide 

and the Associated Acute Toxicity Classification. 

Taxonomic Group Tested Species Acute Toxicity Endpoint 

Acute Study MRID 

and Toxicity 

Classification 

Chronic 

NOAEC 

Birds1

 Bobwhite quail 

LD50 = 2.94 mg a.i./kg-bwt 

(2.33, 4.56) 

Slope = 4.92 (2.18, 7.67) 

417605-03 

(acceptable) 

Very highly toxic No data 

 Bobwhite quail 

LC50 = 14.08 mg a.i./kg-diet 

(8.67, 20.88) 

Slope = 2.78 (1.47, 4.08) 

426718-02 

(acceptable) 

Very highly toxic 

Mammals 

Laboratory rat 

(Rattus 

norvegicus) 

LD50 = 350 mg a.i./kg-bwt 

(male) 

LD50 = 302 mg a.i./kg-btw 

(female) 

41632101 

(Acceptable3

) 

Moderately toxic 

No data 

Insects No data No data 

Freshwater fish2 Rainbow trout 

LC50 = 9.7 mg a.i./L 

(4.9, 14) 

Slope NA 

41767502 

(acceptable) 

moderately toxic 

No data 

Freshwater 

invertebrates Daphnia magna 

EC50 = 0.07 mg a.i./L 

(0.06, 0.09) 

Slope = 5.4 (3.0, 7.8) 

41783701 

(acceptable) 

Very highly toxic 

No data 

Estuarine/marine No data No data 
14 

Table 4. Test Species Evaluated for Assessing Potential Ecological Effects of Starlicide 

and the Associated Acute Toxicity Classification. 

Taxonomic Group Tested Species Acute Toxicity Endpoint 

Acute Study MRID 

and Toxicity 

Classification 

Chronic 

NOAEC 

fish 

Estuarine/marine 

invertebrates No data No data 

Terrestrial plants No data 

Aquatic plants and 

algae No data 

1

 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 

2

 Freshwater fish may be surrogates for aquatic-phase amphibians. 

3

 Study classification made by Health Effects Division (HED). 

5.1. Effects to Aquatic Organisms 

Technical grade starlicide is classified as moderately toxic to freshwater fish, aquatic-phase 

amphibians and is very highly toxic to freshwater aquatic invertebrates on an acute exposure 

basis. Data were not submitted to the Agency to allow for the estimation of acute toxicity to 

estuarine/marine fish and invertebrates, chronic toxicity to freshwater and estuarine/marine fish 

and invertebrates, or toxicity to vascular and non-vascular aquatic plants. 

5.2. Effects to Terrestrial Organisms 

Starlicide is very highly toxic to birds on an acute oral and subacute dietary exposure basis and is 

moderately toxic to mammals on an acute oral exposure basis. Data were not submitted to the 

Agency to allow for the estimation of acute toxicity to terrestrial invertebrates, chronic toxicity 

to birds and mammals, or toxicity to terrestrial plants. 

Previous assessments utilized acute avian (mourning dove and red-winged blackbird) toxicity 

data from USDA/APHIS/Denver Wildlife Research Center (DWRC) (MRID 412672-01). Recent 

review of the starlicide studies for mourning dove (LD50 = 3.1 mg a.i./kg-bwt) and red-winged 

blackbird (LD50 = 2.4 mg a.i./kg-bwt) classified both studies invalid since no control birds were 

included. 

5.3. Degradate toxicity 

Three major degradates have been identified in the environmental fate studies: carbon dioxide in 

the aerobic soil metabolism study, 3-hydroxy-p-toluidine in the aqueous photolysis study, Nacetyl-3-chloro-p-toluidine in the aerobic soil metabolism study and the fish bioaccumulation 

study. The toxicity of the degradates, 3-hydroxy-p-toluidine and N-acetyl-3-chloro-p-toluidine, 

relative to the parent is not known. For the purposes of registration review environmental risk 

assessment, these degradates will be considered to be equally toxic to the parent. Based on 

structural analysis, an assumption of equal toxicity of parent and degradates appears reasonable. 

If information becomes available which indicates that these degradates are not similarly toxic to 

the parent, the risk assessment will be altered accordingly. 
15 

5.4. Ecological Incidents 

A review of the Ecological Incident Information System (EIIS, version 2.1), the ‘Aggregate 

Incident Reports’ (AIR v. 1.0) database, and the Avian Monitoring Information System (AIMS) 

for ecological incidents involving starlicide was completed on May 27, 2011. Two incidents 

were reported in EIIS, one incident was reported in AIMS, and no incidents were reported in 

AIR; the degree of certainty ranged between possible and probable. Mortalities of between 100 

and 300 birds were reported for each incident; two incidents involved starlings and one involved 

cowbirds. These incidents will be discussed in further detail in the risk assessment. If 

information is available, further characterization may include application rates and methods, 

intended targeted species, and legality of use. 

6. Ecosystems Potentially at Risk 

The ecosystems potentially at risk are often extensive in scope; therefore, it may not be possible 

to identify specific ecosystems during the development of a nation-wide ecological risk 

assessment. However, in general terms, terrestrial ecosystems potentially at risk could include 

the treated field and immediately adjacent areas that may receive drift or runoff. Areas adjacent 

to the treated field could include cultivated fields, fencerows and hedgerows, meadows, fallow 

fields or grasslands, woodlands, riparian habitats, and other uncultivated areas. 

Aquatic ecosystems potentially at risk include water bodies adjacent to, or downstream from, the 

treated field and might include impounded bodies such as ponds, lakes and reservoirs, or flowing 

waterways such as streams or rivers. For uses in coastal areas, aquatic habitat also includes 

marine ecosystems, including estuaries. 

7. Assessment Endpoints 

Assessment endpoints represent the actual environmental value that is to be protected, defined by 

an ecological entity (species, community, or other entity) and its attribute or characteristics (EPA 

1998). For starlicide, the ecological entities include the following: birds, reptiles, terrestrialphase amphibians, mammals, freshwater fish, freshwater aquatic-phase amphibians and 

invertebrates, estuarine/marine fish and invertebrates, terrestrial plants, insects, aquatic plants, 

and algae. The attributes for each of these entities include growth, reproduction, and survival. 

8. Conceptual Model 

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves in the 

environment from a source to an ecological receptor. For an ecological pathway to be complete, 

it must have a source, a release mechanism, an environmental transport medium, a point of 

exposure for ecological receptors, and a feasible route of exposure. 
16 

The conceptual model for starlicide provides a written description and visual representation of 

the predicted relationships between starlicide, potential routes of exposure, and the predicted 

effects for the assessment endpoint. A conceptual model consists of two major components: risk 

hypothesis and a conceptual diagram (USEPA 1998). 

As discussed previously, several ecological risk assessments have been conducted by EFED for 

starlicide, including a national level risk assessment supporting the reregistration eligibility 

decision (USEPA 1995). 

8.1. Risk Hypothesis 

A risk hypothesis describes the predicted relationship among the stressor, exposure, and 

assessment endpoint response along with the rationale for their selection. For starlicide, the 

following ecological risk hypothesis is being employed for this national-level ecological risk 

assessment: 

Starlicide, when used in accordance with current labels, can result in off-site 

movement of the compound via runoff leading to exposure of non-target plants 

and animals. Consumption of treated bait and contaminated carcasses may serve 

as a major source of starlicide exposure to wildlife. Exposure in these 

environmental compartments will result in adverse effects upon the survival, 

growth, and reproduction of non-target terrestrial and aquatic organisms. These 

non-target organisms include federally-listed threatened and endangered species. 

8.2. Conceptual Diagram 

The conceptual model assumes that starlicide will be available to non-target organisms and, as 

toxic food bait, will adversely affect terrestrial species. The movement away from the site of 

application in turn represents exposure pathways for a broad range of biological receptors of 

concern (non-target animals) and the potential attribute changes, i.e., effects such as reduced 

survival, growth and reproduction, in the receptors due to starlicide exposure. Figure 1 illustrates 

the anticipated exposure pathways and transport routes to ecological receptors and identifies the 

predicted attribute changes from this exposure. The major sources of exposure of non-target 

terrestrial animals are expected to be ingestion of the formulated food bait and consumption of 

vertebrate body tissues or invertebrates that have eaten the food bait. Exposure via these routes is 

expected primarily for birds and mammals, though it is likely that other terrestrial animals such 

as reptiles and terrestrial amphibians are at risk if they consume invertebrates or tissues of 

vertebrates that have eaten bait. Starlicide may also be consumed by target and non-target 

animals through ingestion of fecal material (coprophagy). 

Terrestrial species may ingest starlicide by drinking contaminated water. Starlicide is applied on 

bait, and it binds only moderately to surfaces. Hence it is possible that it may partition into 

drinking water source (e.g. puddles) compared to that which is available for direct consumption 

on the bait itself; therefore, this route of exposure will be assessed. Since starlicide is not sprayed 
17 

directly onto plants, and because so little is expected to leach from the bait and then be available 

for plant uptake, consumption of starlicide on plants is not being considered as a route of 

exposure. Aquatic species may ingest some bait and may be exposed to starlicide via uptake 

through gills/integument. Dermal and inhalation routes of exposure occur for some pesticides 

(e.g., foliar sprays). However, these are not expected to be important routes of exposure for 

grain-based, avicide food bait because starlicide is not volatile and is not expected to absorb 

appreciably through the skin. 
18 

Figure 1. Conceptual Model Diagram of Starlicide Exposure and Effects in Nontarget Species. Dotted lines in

that have a low likelihood of contributing to ecological risk.

Stressor

Transport Pathways 

Runoff into Water Bodies or Standing Water 

Consumption by 

Terrestrial 

Vertebrates 

Deposition on Ground: Intentional (Broadcast or Hand Application) or Incidental (Bait Station) 

Exposure Media Water Body/ Standing Water Sediment 

Receptors 

Uptake and/or Consumption 

by Aquatic Vertebrates and 

Invertebrates and Aquatic 

Plants

Ingestion of 

Water by 

Terrestrial 

Vertebrates 

Exposed Intact Bait at 

Application Site 

Consumption of Tissues 

 (as prey or carcass) by 

Predators/Scavengers 

Attribute Changes (Direct Effect) 

Individual organisms: 

Reduced Reproduction and 

Survival of Aquatic Organisms 

Individual Organisms

Reduced Reproduction and Survival 

Non-Target Organisms 

Starlicide 

Consumption and/Uptake by Soil Macroinvertebrate

Attribute Changes (Indirect Effect) 

Habitat Integrity: 

Altered plant communities 

Food Chain: 

Reduced prey base

Uplan

(dislodgi

sorbing o
19 

9. Analysis Plan 

In order to address the risk hypothesis, the potential for adverse effects on the environment is 

estimated. The use, environmental fate, and ecological effects of starlicide are characterized and 

integrated to assess the risks. This is accomplished using a risk quotient (ratio of exposure 

concentration to effects concentration) approach. Although risk is often defined as the likelihood 

and magnitude of adverse ecological effects, the risk quotient-based approach does not provide a 

quantitative estimate of likelihood and/or magnitude of an adverse effect. However, as outlined 

in the Overview Document (USEPA 2004), the likelihood of effects to individual organisms 

from particular uses of starlicide is estimated using the probit dose-response slope and either the 

level of concern (discussed below) or actual calculated risk quotient value. 

This analysis plan will be revisited and may be revised depending upon the information 

submitted by the public in response to the opening of the Registration Review docket for 

starlicide. 

9.1. Stressors of Concern 

The parent compound, starlicide (3-chloro-p-toluidine hydrochloride), is the toxicant that will be 

assessed. Degradates (3-hydroxy-p-toluidine and N-acetyl-3-chloro-p-toluidine) may be 

considered, but their toxicity is unknown. Toxicity of degradates will be assumed to be 

equivalent to parent compound in the absence of data to suggest otherwise. 

Evaluation of pesticide mixtures is beyond the scope of this assessment because of the myriad 

factors that cannot be quantified based on the available data. Those factors include identification 

of other possible co-contaminants and their concentrations, differences in the pattern and 

duration of exposure among contaminants, and the differential effects of other physical/chemical 

characteristics of the receiving waters (e.g. organic matter present in sediment and suspended 

water). Evaluation of factors that could influence additivity/synergism is beyond the scope of this 

assessment and the capabilities of the available data to allow for an evaluation. However, it is 

acknowledged that not considering mixtures could over- or under-estimate risks depending on 

the type of interaction and factors discussed above. The assessment will, however, analyze the 

toxicity of formulated products (including formulations involving more than one active 

ingredient) and will determine whether formulated products are more toxic than the technical 

grade active ingredient data used for assessing both direct and indirect risks. 

9.2. Measures of Exposure 

In order to estimate risks of starlicide exposures in aquatic and terrestrial environments, all 

exposure modeling and resulting risk conclusions will be based on maximum application rates 

and methods cited in Table 1 and will be estimated for each use of starlicide. Measures of 

exposure are based on aquatic and terrestrial models that predict estimated environmental 

concentrations (EECs) of starlicide. The model used to predict Tier 1 aquatic EECs is GENEEC. 

If Tier 1 EECs result in LOC exceedances, a Tier 2 assessment will be performed using PRZM 
20 

and EXAMS. In addition, primary exposure to bait and secondary exposure to starlicide 

poisoned carcasses will be considered for measures of exposure to terrestrial organisms. This 

assessment only considered exposure and toxicity to parent starlicide. 

9.2.1 Estimating Aquatic Exposure 

The exposure assessment for this use is being conducted at the first tier using the GENEEC 

model, version 2.0, dated August 1, 2001. GENEEC is a metamodel of the Tier 2 models PRZM 

and EXAMS and as such mimics the output of these models. However, GENEEC is hard-wired 

to a single, high exposure scenario which is intended to be protective of aquatic environments for 

all crops on a national basis. While application to control nuisance birds is not per se to an 

agricultural crop, the similarities are sufficient that EECs generated by GENEEC would still be 

expected to be protective of applications of starlicide on a national basis. Rather than the timeseries of concentration that is the output at Tier 2, GENEEC produces point estimates of 1-in-10 

year peaks and means of specified duration (e.g. 4 day mean, 21-day mean) based on a more 

limited set of input data. If risks are above levels of concern at Tier 1 using GENEEC, more 

refined modeling at Tier 2 can be conducted which considers crop specific location information 

and additional fate data such as vapor pressure. 

While the specific scenario built into GENEEC is a 10 ha field draining into a 1 ha pond, 2 

meters deep, with no outlet, this scenario is intended to serve as a surrogate for a wide variety of 

small vulnerable water bodies that occur near the top of watersheds. These include prairie 

potholes, swamps, bogs, and other wetlands, playa lakes, and zero and first-order streams. 

Larger water bodies such as second-order and higher streams and rivers, and lakes reservoirs, are 

expected to be less vulnerable (lower EECs) than the standard pond built into GENEEC as they 

large dilution ratios, and they are unlikely to have 100% of the watershed committed to one use 

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

organisms. The 1-in-10-year 60-day mean is used for assessing chronic exposure to fish and 

aquatic-phase amphibians. The 1-in-10-year 21-day mean is used for assessing chronic exposure 

to aquatic invertebrates. 

9.2.2 Estimating Primary Terrestrial Exposure 

EFED’s exposure assessment for avicide differs from that for most other pesticides. For an 

avicide, the bait itself is the potential food item of concern. Thus, the amount of active ingredient 

in the formulated bait is used as an EEC. This information is used to estimate the amount of 

grain bait that birds and mammals of various sizes need to consume to obtain a dose expected to 

be lethal to 50% of the individuals in the population (i.e., LD50 dose). Estimates of foodingestion rates (g dry matter per day) are determined from established allometric equations 

presented in the Wildlife Exposure Factors Handbook (USEPA 1993). The concentration of 

starlicide in grain bait is also used to estimate initial dietary exposure (mg a.i. per kg in bait) 

which in turn is used to calculate avian and mammalian dietary RQs. 

9.2.3 Estimating Secondary Terrestrial Exposure 

Secondary exposure analysis (from carcass) requires consideration of residues in tissues of target 
21 

and non-target organisms that are commonly consumed by predators and scavengers. Moreover, 

it is important to know how long the residue persists in body tissues. Estimated residue 

concentrations in carcasses may be estimated in several ways depending on available data. If 

residue concentrations for target or non-target animals fed starlicide are available, these data can 

be used to estimate starlicide body burden. A second approach is to estimate the quantity of 

starlicide a primary consumer must ingest to reach mortality; this intake amount will then be 

converted to a body burden estimate. The method(s) used in the registration review assessment 

will be determined upon evaluation of all available data. 

9.3. Measures of Effect 

Ecological effect data are used as measures of direct and indirect effects to biological receptors. 

Data were obtained from registrant-submitted studies or from literature studies identified by 

ECOTOX. The ECOTOXicology database (ECOTOX) will be searched in order to provide more 

ecological effects data to bridge existing data gaps. ECOTOX is a source for locating single 

chemical toxicity data and potential chemical mixture toxicity data for aquatic life, terrestrial 

plants, and wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research 

and Development, and the National Health and Environmental Effects Research Laboratory's 

Mid-Continent Ecology Division. In addition, available toxicity data from federal laboratories 

will be evaluated and used as applicable. 

Information on the potential effects of starlicide on non-target animals is also collected from the 

Ecological Incident Information System. The EIIS is a database containing adverse effect 

(typically mortality) reports on non-target organisms where such effects have been associated 

with the use of pesticides. 

Where available, sublethal effects observed in both registrant-submitted and open literature 

studies will be evaluated qualitatively. Such effects have included behavioral changes (e.g., 

lethargy, changes in coloration and effects olfaction). Quantitative assessments of risks, though, 

are limited to those endpoints that can be directly linked to the Agency’s assessment endpoints of 

impaired survival, growth and reproduction. 

The assessment of risk for direct effects to non-target organisms makes the assumption that 

toxicity of starlicide to birds is similar to terrestrial-phase amphibians and reptiles. The same 

assumption is made for fish and aquatic-phase amphibians. 

The acute measures of effect used for animals in this screening-level assessment are the LD50, 

LC50 and EC50. LD stands for "Lethal Dose", and LD50 is the amount of a material, given all at 

once, that is estimated to cause the death of 50% of the test organisms. LC stands for “Lethal 

Concentration” and LC50 is the concentration of a chemical that is estimated to kill 50% of the 

test organisms. EC stands for “Effective Concentration” and the EC50 is the concentration of a 

chemical that is estimated to produce a specific effect in 50% of the test organisms. Endpoints 

for chronic measures of exposure for listed and non-listed animals are the NOAEL/NOAEC and 

NOEC. NOAEL stands for “No Observed-Adverse-Effect-Level” and refers to the highest tested 

dose of a substance that has been reported to have no harmful (adverse) effects on test 
22 

organisms. The NOAEC (i.e., “No-Observed-Adverse-Effect-Concentration”) is the highest test 

concentration at which none of the observed effects were statistically different from the control. 

The NOEC is the No-Observed-Effects-Concentration. For non-listed plants, only acute 

exposures are assessed (i.e., EC25 for terrestrial plants and EC50 for aquatic plants); for listed 

plants, either the NOAEC or EC05 is used. 

9.4. Integration of Exposure and Effects 

Risk characterization is the integration of exposure and ecological effects characterization to 

determine the potential ecological risk from the use of starlicide on crops listed in Table 1 and 

the likelihood of direct and indirect effects to non-target organisms in aquatic and terrestrial 

habitats. The exposure and toxicity effects data are integrated in order to evaluate the risks of 

adverse ecological effects on non-target species. For the assessment of starlicide risks, the risk 

quotient (RQ) method is used to compare exposure and measured toxicity values. EECs are 

divided by acute and chronic toxicity values. The resulting RQs are then compared to the 

Agency’s LOCs (USEPA 2004). These criteria are used to indicate when starlicide’s uses, as 

directed on the label, have the potential to cause adverse direct or indirect effects to non-target 

organisms. As noted previously, where data are lacking on the toxicity of starlicide, risk will be 

presumed. 

 

9.4.1. Deterministic and Probabilistic Assessment Methods 

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

based approach described in the risk assessment. An effort will be made to further qualitatively 

describe risk using probabilistic tools that the Agency has developed. These tools have been 

reviewed by FIFRA Scientific Advisory Panels and have been deemed as appropriate means of 

refining assessments where deterministic approaches have identified risks. 

9.5. Endangered Species Assessments 

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to Federally-listed threatened and/or endangered (listed) species from 

registered uses of starlicide. This assessment will be conducted in accordance with the Overview 

Document (USEPA 2004), provisions of the ESA, and the Services’ Endangered Species 

Consultation Handbook (USFWS/NMFS 1998). 

The assessment of effects associated with the registration of starlicide is based on an action area. 

The action area is considered to be the area directly or indirectly affected by the federal action, as 

indicated by the exceedance of Agency LOCs used to evaluate direct or indirect effects. The 

Agency’s approach to defining the action area under the provisions of the Overview Document 

(USEPA 2004) considers the results of the risk assessment process to establish boundaries for 

that action area with the understanding that exposures below the Agency’s defined LOCs 

constitute a no-effect threshold. For the purposes of this assessment, attention will be focused on 

the footprint of the action (i.e., the area where starlicide application occurs), plus all areas where 

offsite transport may result in potential exposure that exceeds the Agency’s LOCs. Specific 
23 

measures of ecological effect that define the action area for listed species include any direct and 

indirect effects and/or potential modification of its critical habitat, including reduction in 

survival, growth, and reproduction as well as the full suite of sub-lethal effects available in the 

effects literature. Therefore, the action area extends to a point where environmental exposures 

are below any measured lethal or sub-lethal effect threshold for any biological entity at the whole 

organism, organ, tissue, and/or cellular level of organization. In situations where it is not 

possible to determine the threshold for an observed effect, the action area is not spatially limited 

and is assumed to be the entire United States. 

9.6. Drinking Water Assessment 

A drinking water assessment will not be performed for starlicide because there are no food uses 

for this pesticide. Drinking water assessments are performed to support dietary risk assessments 

and dietary risk assessments are only required to support tolerances for use of food crops. Since 

there is no food use for starlicide, no tolerance is required. 

 10. Endocrine Disruptor Screening Program 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 

chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of its reregistration decision, EPA reviewed these data and selected 

the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard 

database. However, as required by FFDCA section 408(p), starlicide is subject to the endocrine 

screening part of the Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between 
24 

October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 

chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. Starlicide is 

not among the group of 58 pesticide active ingredients on the initial list to be screened under the 

EDSP. Accordingly, as part of registration review, EPA will issue future EDSP orders/data callins, requiring the submission of EDSP screening assays for starlicide. For further information on 

the status of the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the test 

guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/. 

11. Preliminary Identification of Data Gaps 

11.1. Fate 

The Agency is currently requesting the following fate and transport studies (Table 5) to support 

registration review of starlicide: 

 835.1230 – soil column leaching 

 835.1240 – adsorption/desorption 

 835.2410 – photodegradation on soil 

 835.4100 – aerobic soil metabolism 

 835.4300 – aerobic aquatic metabolism 

 835.4400 – anaerobic aquatic metabolism 

 835.6100 – terrestrial field dissipation 

- environmental chemistry method : soil 

 835.6200 – aquatic field dissipation 

- environmental chemistry method : water 

Either the soil column leaching or the adsorption desorption study is required to satisfy the 

mobility data requirement. The adsorption desorption study is preferred, but the soil column 

leaching study can be used when the pesticide degrades too rapidly to be measured by a batch 

equilibrium study. The Agency currently has no environmental metabolism study which is 

sufficient to estimate degradation rates. In addition, data requirement have changed since 

reregistration of starlicide and anaerobic soil metabolism, aerobic aquatic metabolism, and 

anaerobic aquatic metabolism studies are now required for all compound with terrestrial outdoor 

use. Note that four soils are now required to support the aerobic soil metabolism data 

requirement. The anaerobic soil metabolism study is required for these use patterns in the CFR 

Part 158 but this study will not produce data which will be used in the risk assessment so it is not 

being requested. If metabolism data are not submitted which can be used to quantify the 

degradation rate, the Agency will conservative estimation techniques based on the appearance of 

degradates, or by assuming the starlicide does not degrade. A terrestrial field dissipation study is 

required to support outdoor uses. However, feeding or efficacy studies which track the rate of 

consumption of bait and show that the most of the bait is consumed by the target species can be 

submitted to support the field dissipation requirement. An Environmental Chemistry Method for 
25 

Soil is required to support the field dissipation study. An Environmental Chemistry Method for 

Water is also needed as there are aquatic risks exceeding the level of concern in the RED. 
26 

Table 5. Available environmental fate data for starlicide

158 

Guideline 

(OPPTS) 

Description MRID Classification Guideline 

Fulfilled? Comments 

835.1230 

(163-1) 

 Leaching 43284503 unacceptable No Study did not address 

degradates; 

835.1240 

(163-1) 

Adsorption/Desorption 43284502 supplemental No new study required

 835.1410 

(163-2) 

Laboratory Volatility not required Yes 

 835.2120 

(161-1) 

Hydrolysis 

41760501 acceptable 

Yes 

 835.2240 

(161-2) 

Photodegradation in 

water 

42830601 

42838801 

acceptable Yes 

835.2370 

(161-4) 

Photodegradation in air not required Yes 

835.2410 

(161-3) 

Photodegradation on 

soil 

 No no data; study required 

 835.4100 

(162-1) 

Aerobic soil 

metabolism 43284501 

supplemental No rate not quantified; 

replacement study 

required 

835.4200 

(162-2) 

Anaerobic soil 

metabolism 

required No not being requested – 

not needed for risk 

assessment 

 835.4300 

(162-4) 

Aerobic aquatic 

metabolism 

required No study required 

 835.4400 

(162-3) 

Anaerobic Aquatic 

Metabolism 

required No study required 

 835.6100 

(164-1) 

Terrestrial Field 

Dissipation 

required No study required 

835.6200 

(164-2) 

Aquatic Field 

Dissipation 

not required Yes 

835-6300 

(164-3) 

Forestry Field 

Dissipation 

not required Yes 

850.1730 

(165-4) 

Fish Bioconcentration 

Factor 

43069801 acceptable Yes 

NGS Drinking Water 

Treatment 

not required Yes 

835.6100 

Footnote 7 

Environmental 

Chemistry Method in 

soil 

required No supports field 

dissipation; required 

835.6200 

Footnote 7 

Environmental 

Chemistry Method in 

Water 

required No required as there are 

aquatic LOC 

exceedances in RED 
27 

11.2. Effects 

Although many submissions have been made to provide data on the effects of starlicide to 

aquatic and terrestrial organisms, data gaps still exist (Tables 6-8). Since the RED was signed, 

the Agency has finalized its update to the data requirements in 40 CFR part 158. These updated 

data requirements were promulgated in 2007 and 2008. 

 11.2.1 Toxicity of Starlicide to Terrestrial Animals 

Acute passerine toxicity (850.2100) 

Previous assessments utilized acute avian (mourning dove and red-winged blackbird) toxicity 

data from USDA/APHIS/Denver Wildlife Research Center (DWRC) (MRID 412672-01). Recent 

review of the starlicide studies for mourning dove (LD50 = 3.1 mg a.i./kg-bwt) and red-winged 

blackbird (LD50 = 2.4 mg a.i./kg-bwt) classified both studies invalid since no control birds were 

included. The revised Part 158 data requirements specify that acute avian oral toxicity data be 

submitted for either one waterfowl or one upland game species and one passerine species. The 

available acute oral toxicity data, when compared to estimated environmental concentrations, 

indicate that levels of concern are exceeded for birds on an acute basis. Because passerine 

species have higher metabolic rates due to their smaller sizes than either waterfowl or upland 

game bird species and because they may utilize different metabolic pathways, they may be more 

or less sensitive to starlicide. In order to properly characterize risk to passerines, an avian oral 

toxicity test is required for passerine birds. A passerine study protocol must be submitted for 

review by the Agency prior to initiation of the study. These data will be used to refine the 

screening-level risk assessment by determining whether there are differences in avian species 

sensitivity to starlicide between currently tested passerine and upland game and/or waterfowl 

species that are beyond the simple allometric predictions currently employed in the absence of 

such passerine data. The current extrapolation method may be under- or over-estimating risks to 

passerines. 

Chronic avian toxicity (850.2300)

No avian reproduction studies have been submitted. The RED did not identify a chronic concern 

for the use of starlicide since the expected exposure time was expected to be short. Now two 

avian reproduction studies, one with a waterfowl and one with an upland game bird, are required 

to support all terrestrial use patterns. Because some pesticides are stable in the environment or 

can be stored in plant tissues that may be used by birds as a food source, avian reproduction 

testing (guideline 850.2300) was conditionally required for pesticides to which birds are exposed 

repeatedly or continuously during or preceding the breeding season. In addition, research has 

shown that even short-term exposures to pesticides can lead to significant adverse reproductive 

effects and that adverse effects on avian reproduction can occur at levels of exposure several 

magnitudes lower than those that can cause acutely toxic effects. For example, several 

organophosphorus insecticides have been shown to significantly reduce egg production and lead 

to changes in eggshell quality within days of dietary exposure. These data will be used to 

identify potential chronic risks to non-target birds from exposure to starlicide. The data will 

reduce uncertainties associated with the current risk assessment for birds and will improve the 
28 

Agency’s understanding of the potential effects of starlicide on terrestrial species. If chronic 

effects data are not submitted, than chronic risk to birds from exposure to starlicide will be 

assumed. 

Acute honeybee oral toxicity (non-guideline)

At this time, no data are available to define the toxicity of starlicide to honey bees on an acute 

exposure basis. Given that the labels prescribe that the pesticide be coated on baits (many of 

which would be attractive to insects); terrestrial invertebrates have the potential to be exposed to 

starlicide by contacting and consuming the bait. It is expected that the major exposure route for 

non-target insects would be through consumption, not through contact. Therefore, EFED is 

requesting that the registrant submit an acute oral exposure study with honey bees (nonguideline). A DCI justification table is included as Attachment 1. Although this is not an EPA 

guideline study, guidelines are available. For example, OECD has an acute oral toxicity study 

with honey bees (OECD 213). These data will be used to identify potential risks to non-target, 

terrestrial invertebrates, including pollinators, from acute exposure to starlicide. The data will 

reduce uncertainties associated with the current risk assessment for terrestrial insects and will 

improve the Agency’s understanding of the potential effects of starlicide on terrestrial species. If 

acute oral effects data are not submitted, than risk to terrestrial insects from acute exposure to 

starlicide will be assumed. 

Table 6. Available ecological effects data for terrestrial animals exposed to technical 

starlicide. 

158 

Guideline 

(OPPTS) 

Description MRID/ 

Accession Classification Guideline Fulfilled? Comments 

850.2100 

(71-1) Avian oral toxicity 41760502,41760503 

Acceptable 

Acceptable No Requesting acute oral for passerine species 

850.2200 

(71-2) 

Avian dietary 

toxicity 

42671801

42671802 

Acceptable 

Acceptable Yes 

850.2300 

(71-4) Avian reproduction No data No 

Requesting avian reproduction 

for both bobwhite quail and 

mallard duck 

850.3020 

(141-1) 

Honeybee acute 

contact toxicity No data No Requesting honeybee acute 

oral in lieu of this study 

NGS Honeybee acute oral NAa Requesting honeybee acute 

oral in lieu of the 850.3020 

a

 NA – Not applicable, non-OCSPP guideline study. 

 
29 

11.2.1 Toxicity of Starlicide to Aquatic Animals 

Acute saltwater fish (850.1075), acute mysid (850.1035), and oyster shell growth (850.1025) 

Estuarine/marine fish and invertebrate acute toxicity studies are now required using the TGAI to 

support all outdoor end-use product uses. No estuarine/marine fish or invertebrate studies have 

been submitted to the Agency that could be used for risk assessment. Starlicide can be applied to 

areas that could be in close proximity to estuarine/marine environments such as airports and 

industrial sites for which the targets are a variety of gull species. (EPA Reg. No. 56228-17). All 

of the estuarine aquatic toxicity studies would allow the Agency to refine the screening level risk 

assessment of the RED. The Agency would be able to assess the potential risks to 

marine/estuarine organisms in future risk assessments, including the likelihood that the use of 

starlicide can potentially impact endangered species in aquatic communities, either by direct 

effects on fish and/or invertebrates or by indirect effects by reducing food sources. 

Freshwater invertebrate lifecycle (850.1300) 

One freshwater invertebrate life-cycle study is required to support all terrestrial use patterns. The 

potential chronic risk of starlicide to freshwater invertebrates is indicated by the fact that 

starlicide is very highly toxic on an acute basis to freshwater invertebrates. These data are 

critical to insure the Agency can accurately calculate chronic risk to freshwater invertebrates. 

The acute toxicity of starlicide to freshwater invertebrates indicates the potential chronic risk to 

animals in this taxon. Based on GENEEC runs from the RED, the 21-day EEC was 3.78 μg/L; 

therefore, if the chronic NOAEC for freshwater invertebrates was ≤ 3.78 μg/L, the chronic LOC 

(=1) would be exceeded. The LC50 for daphnids is 70 μg/L; therefore, the chronic NOAEC 

would only need to be one order of magnitude lower than the acute endpoint. This difference 

between acute and chronic toxicity endpoints is very reasonable and is frequently seen in 

pesticide data. Without this study, the Agency would have to presume chronic risk to listed and 

non-listed freshwater invertebrates, but would not be able to quantify the risk. 
30 

Table 7. Available ecological effects data for aquatic animals exposed to technical 

starlicide. 

Guideline Description MRID/ 

Accession Classification Guideline Fulfilled? Comments 

850.1075 

(72-1) 

Freshwater fish – 

Acute toxicity 

41767501 

41676502 

Acceptable 

Acceptable Yes 

850.1075 

(72-3) 

Saltwater fish – 

Acute toxicity No data No Requesting for one species 

850.1010 

(72-2) 

Freshwater 

invertebrates – 

Acute toxicity 

41783701 Acceptable Yes 

850.1025 

850.1035 

(72-3) 

Saltwater 

invertebrates – 

Acute toxicity 

41783701 Invalid No Requesting for mysid and 

oyster shell growth 

850.1300 

(72-4) 

Freshwater 

invertebrate – 

life cycle test 

No data No Requesting for daphnid 

850.1350 

(72-4) 

Saltwater 

invertebrates – 

life cycle test 

No data No 

Data have not been submitted 

to fulfill this guideline. A data 

gap was not identified as these 

data are not necessary for risk 

assessment at this time. 

850.1400 

(72-4) Freshwater fish – 

early life stage test No data No 

Data have not been submitted 

to fulfill this guideline. A data 

gap was not identified as these 

data are not necessary for risk 

assessment at this time. 

850.1400 

(72-4) 

Saltwater fish – 

early life stage test No data No 

Data have not been submitted 

to fulfill this guideline. A data 

gap was not identified as these 

data are not necessary for risk 

assessment at this time. 

850.1500 

(72-5) 

Fish – 

life cycle test No data No 

Data have not been submitted 

to fulfill this guideline. A data 

gap was not identified as these 

data are not necessary for risk 

assessment at this time. 

11.2.1 Toxicity of Starlicide to Plants 

No toxicity data are currently available to assess the risk of starlicide to terrestrial or aquatic 

plants. Since starlicide has terrestrial outdoor uses, Tier II seedling emergence, aquatic, and 

aquatic non-vascular studies are required. Tier I and/or II vegetative vigor studies are not 

requested at this time since drift is not expected to be a significant exposure route. For the 

required terrestrial and aquatic plant studies, the registrant may choose to submit Tier I studies to 

the Agency, and if these demonstrate that starlicide at the maximum expected exposure 

concentrations has no effect on growth and/or survival of plants, the Agency may consider the 
31 

Tier II requirements to be met. 

These phytotoxicity data are needed to evaluate the level of pesticide exposure to non-target 

terrestrial and aquatic plants and to assess the impact of pesticides on endangered and threatened 

plants. Without these data, the Agency would have to presume risk to listed and non-listed 

plants, but would not be able to quantify the risk. Presumption of risk to non-listed terrestrial and 

aquatic plants would result in the presumption of risk on other taxa through the potential for 

indirect effects by changes in habitat and reduction in food sources. 

Table 8. Available ecological effects data for terrestrial and aquatic plants exposed to 

starlicide and remaining data gaps. 

Guideline Description MRID Classification Guideline 

Fulfilled? 

Comments 

850.4100 

(122-1) 

Terrestrial Plant 

toxicity: Tier I seedling 

emergence 

No data No 

Data have not been submitted 

to fulfill this guideline. A data 

gap was not identified as these 

data are not necessary for risk 

assessment at this time. 

850.4100 

(123-1) 

Terrestrial Plant 

toxicity: Tier 2 

seedling emergence 

No data No Requesting Tier II study for 

ten species 

850.4150 

(122-1) 

Terrestrial Plant 

toxicity: Tier I 

vegetative vigor 

No data No 

Data have not been submitted 

to fulfill this guideline. A data 

gap was not identified as these 

data are not necessary for risk 

assessment at this time. 

850.4150 

(123-1) 

Terrestrial Plant 

toxicity: Tier 2 

vegetative vigor 

No data No 

Data have not been submitted 

to fulfill this guideline. A data 

gap was not identified as these 

data are not necessary for risk 

assessment at this time. 

850.5400 

(123-2) 

Aquatic Plant Growth: 

algae No data No Requesting Tier II study for four species 

 850.4400 

(123-2) 

Aquatic Plant Growth: 

vascular plants 

No data No Requesting Tier II study for 

Lemna gibba

12. References 

Open Literature Citations 

Knittle, C.E., E.W. Schafer Jr., and K.A. Fagerstone. 1990. Status of compound DRC-1339 

registration. Proceedings of the Fourteenth Vertebrate Pest Conference 1990. pp 311-

313. 
32 

Schafer, E.W., Jr. 1984. Potential primary and secondary hazards of avicides. Proc. Vertebr. Pest 

Conf. 11:217-222. 

U.S. Environmental Protection Agency. 1993. Wildlife Exposure Factors Handbook. Office of 

Research and Development. December. EPA/600/R-93/187 

U.S. Environmental Protection Agency.1995. Reregistration Eligibility Decision (RED): 

Starlicide (3-chloro-p-toluidine hydrochloride). September 1995. EPA-738-R-96-003. 

U.S. Environmental Protection Agency. 1998. Guidelines for Ecological Risk Assessment. 

United States Environmental Protection Agency (USEPA). Risk Assessment Forum. 

Office of Research and Development. Available at 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12460 (Accessed June 19, 2009). 

U.S. Environmental Protection Agency. 2004. Overview of the Ecological Risk Assessment 

Process in the Office of Pesticide Programs. US EPA Office of Pesticide Programs, 

Environmental Fate and Effects Division. 

U.S. Fish and Wildlife Service and National Marine Fisheries Service. 1998. Endangered Species 

Consultation Handbook. Procedures for Conducting Consultation and Conference 

Activities Under Section 7 of the Endangered Species Act. 

http://www.nmfs.noaa.gov/pr/pdfs/laws/esa_section7_handbook.pdf 

Data Submitted To Support Registration 

41267201 Knittle, C. (1989) Summary of Currently Available Avian Single-dose Oral LD50 

Data for the Chemical 3-Chloro-4-methylbenzenamine Hydrochloride. Unpublished 

study prepared by Denver Wildlife Research Center. 153 p. 

41760502 Fletcher, D.; Pedersen, C. (1990) Compound 1339: 21-Day Acute Oral LD50 Study 

in Mallard Ducks: Lab Project Number: 89 DD 71. Unpublished study prepared by BioLife Associates, Ltd. 148 p. 

41760503 Fletcher, D.; Pedersen, C. (1990) Compound 1339: 21-Day Acute Oral LD50 Study in 

Bobwhite Quail: Lab Project Number: 89 QD 135. Unpublished study prepared by BioLife Associates, Ltd. 176 p. 

42671801 Pedersen, C.; Lesar, C. (1993) Compound DRC-1339 98% Concentrate (Starlicide): 

12-Day Acute Dietary LC50 Study in Mallard Ducklings: Lab Project Number: 90 DC 

151. Unpublished study prepared by Bio-Life Associates, Ltd. 220 p. 

42671802 Pedersen, C.; Lesar, C. (1993) Compound DRC-1339 98% Concentrate (Starlicide): 

12-Day Acute Dietary LC50 Study in Bobwhite Quail: Lab Project Number: 90 QC 155. 

Unpublished study prepared by Bio-Life Associates, Ltd. 214 p. 
33 

41767501 Bowman, J. (1991) Acute Toxicity of DRC-1339 To Bluegill (Lepomis macrochirus): 

Lab Project Number: 38319: QA-141. Unpublished study prepared by Analytical BioChemistry Labs., Inc. 105 p. 

41767502 Bowman, J. (1991) Acute Toxicity of DRC-1339 to Rainbow Trout Oncorhynchus 

mykiss): Lab Project Number: 38318: QA-140. Unpublished study prepared by Analytical 

Bio-Chemistry Labs., Inc. 110 p. 

41783701 Blasberg, J.; Herzog, D. (1991) Acute Toxicity of DRC 1339 to Daphnia magna: Lab 

Project Number: 38320: 139. Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 98 p. 

41609301. Ferder, T., and C. Fickerson. 1990. Product Chemistry Data: Purina Starlicide 

Technical Contains 97% (3-Chloro-p-toluidine hydrochloride). Unpublished study 

prepared by Purina Mills Inc. 162 p. 

41760501. Kimball, B., S. Greiner, and E. Mishalanie. 1990. Environmental Fate Study: 

Hydrolysis of 3-Chloro-p-toluidine Hydrochloride: Lab Project Number: QA-144. 

Unpublished study prepared by Denver Wildlife Research Center. 124 p. 

42830601. Yao, D., T. Mill. 1993. Aquatic Photolysis Study of 3-Chloro-p-Toluidine 

Hydrochloride: Lab Project Number: 3743-20: QA-268. Unpublished study prepared by 

SRI International Chemistry Lab. 64 p. 

42838801. Yao, D., and T. Mill. 1993. Aquatic Photolysis Study of 3-Chloro-p-Toluidine 

Hydrochloride: Lab Project Number: 3743-20: QA-268. Unpublished study prepared by 

SRI International Chemistry Lab. 64 p. 

43284501. Spanggord, R., and G. Gordon. 1994. Aerobic Soil Metabolism Study of 3-Chloro-pToluidine Hydrochloride: Lab Project Number: 3743-N003-93: QA-270. Unpublished 

study prepared by SRI International. 73 p. 

43284502. Irwin, K., and R. Podoll 1994. Sorption and Desorption Study of 3-Chloro-pToluidine Hydrochloride: Lab Project Number: 3743-N005-93: QA-271. Unpublished 

study prepared by SRI International. 75 p. 

43284503. Irwin, K., and R. Podoll. 1994. Aged Leaching Study of 3-Chloro-p-Toluidine 

Hydrochloride: Lab Project Number: 3743-N004-93: QA-362. Unpublished study 

prepared by SRI International. 70 p. 

43069801. Schocken, M. 1993. Starlicide (3-chloro-p-toluidine hydrochloride, CPTH)--

Bioconcentration and Elimination of (carbon 14) Residues by Bluegill Sunfish (Lepomis 

macrochirus): Amended Final Report: Lab Project Number: 3743-50: 

287.1192.6105.140: 93-7-4855. Unpublished study prepared by Springborn Labs, Inc. 

112 p. 

 
34 

Attachment 1: Non-guideline Study DCI Justifications 

Guideline Number: non-guideline 

Study Title: Honey Bee Acute Oral Toxicity Test using the Technical

Rationale for Requiring the Data

Terrestrial invertebrate toxicity data are required to quantitatively assess the potential 

impacts on this group of organisms. At this time, no data are available to define the 

toxicity of starlicide to honey bees on an acute exposure basis. Given that the labels 

prescribe that the pesticide be coated on baits (many of which would be attractive to 

insects); terrestrial invertebrates have the potential to be exposed to starlicide by 

contacting and consuming the bait. It is expected that the major exposure route for nontarget insects would be through consumption, not through contact. 

US EPA does not have a guideline for the acute oral honey bee study; however, the OECD 

213 guideline could be used for protocol development. 

Practical Utility of the Data 

How will the data be used? The honeybee study would allow the Agency to analyze 

pollinators and other non-target terrestrial insects. The effects data would be used to 

determine the likelihood that the risks can potentially impact terrestrial invertebrate 

communities. The data will reduce uncertainties associated with the current risk 

assessment for terrestrial invertebrates and will improve our understanding of the potential 

effects of starlicide. 

How could the data impact the Agency’s future decision-making? If future 

endangered species risk assessments are performed without these data, the Agency would 

have to assume that starlicide "may affect" endangered terrestrial insects directly (and 

endangered species from other taxa indirectly), and use of starlicide might need to be 

restricted in areas where endangered species could be exposed. The lack of these data will 

limit the flexibility the Agency and registrants have in coming into compliance with the 

Endangered Species Act and could result in use restrictions for starlicide which are 

unnecessarily severe.