OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

September 1, 2015

PC Code: 085712 

DP Barcode: 427301

MEMORANDUM 

SUBJECT: Registration Review: Problem Formulation for Nicarbazin (OvoControl P) for 

Reducing Hatchability in Pigeons. 

FROM: Christina Wendel, Biologist 

Richard Shamblen, Biologist 

Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

REVIEWED

BY: Nick Federoff, Wildlife Biologist 

R. David Jones, PhD., Senior Agronomist 

Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

THROUGH: Brian Anderson, Branch Chief 

Elyssa Arnold, Risk Assessment Process Leader 

Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

TO: Bonnie Adler, Chemical Review Manager 

Jill Bloom, Team Leader 

Linda Arrington, Branch Chief 

Risk Management and Implementation Branch 5 

Pesticide Re-evaluation Division (7508P) 

RICHARD SHAMBLEN

Digitally signed by RICHARD SHAMBLEN 

DN: c=US, o=U.S. Government, ou=USEPA, ou=Staff, 

cn=RICHARD SHAMBLEN, dnQualifier=0000051207 

Date: 2015.09.01 12:16:46 -04'00'

2015.09.01 13:28:28 -04'00'

ROBERT JONES 

2015.09.02 15:15:36 -04'00'

2015.09.02 16:36:43 

-04'00'

2015.09.03 

13:52:45 -04'00'
2



1. Executive summary ................................................................................................................. 3

2. Introduction ............................................................................................................................. 6

a. Mode of Action .................................................................................................................... 6

3. Use Characterization ............................................................................................................... 7

4. Conclusions from Previous Risk Assessments ....................................................................... 8

a. Ecological Risk Assessment ................................................................................................ 8

b. Drinking Water Exposure Assessments ............................................................................. 10

c. Clean Water Act Programs ................................................................................................ 10

5. Environmental Fate and Transport Characteristics ............................................................... 10

a. Physical Properties ............................................................................................................. 10

b. Degradation Characteristics ............................................................................................... 12

c. Study Waiver requests ....................................................................................................... 14

d. Degradates.......................................................................................................................... 14

6. Receptors............................................................................................................................... 14

a. Effects to Aquatic Organisms ............................................................................................ 15

b. Effects to Terrestrial Organisms ........................................................................................ 16

c. Ecological Incidents ........................................................................................................... 16

7. Exposure Pathways of Concern ............................................................................................ 17

a. Background ........................................................................................................................ 18

b. Potential Exposure to Terrestrial Wildlife ......................................................................... 18

c. Secondary Exposure by Predators and Scavengers ........................................................... 19

d. Potential Exposure to Aquatic Environments .................................................................... 19

e. Ecological Drinking Water Exposure Pathways ................................................................ 19

8. Analysis Plan ........................................................................................................................ 21

a. Stressors of Concern .......................................................................................................... 22

b. Measures of Exposure ........................................................................................................ 22

c. Measures of Effect ............................................................................................................. 23

d. Endangered Species Assessments ...................................................................................... 24

e. Endocrine Disruptor Screening Program ........................................................................... 24

9. Preliminary Identification of Data Gaps ............................................................................... 24

a. Environmental Fate ............................................................................................................ 25

b. Effects ................................................................................................................................ 27

10. References .......................................................................................................................... 31

a. Submitted Environmental Fate Studies .............................................................................. 33

b. Submitted Ecological Toxicity Studies .............................................................................. 35

APPENDIX A. SIP Inputs and Outputs for Nicarbazin (DNC & HDP components) .................. 39
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 nicarbazin (PC code 085712). 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 nicarbazin. This document also identifies additional studies that 

would be beneficial to the conduct of an ecological risk assessment. 

Nicarbazin is made up of two components, DNC and HDP (see Section 2 for further details). HDP 

acts as the synergist that aids absorption of the toxicant, DNC. Ecological risk assessments have 

been conducted on nicarbazin, for both OvoControl G (no longer registered) and OvoControl P 

(currently registered). Conclusions from the previous assessments determined that based on very 

limited guideline and literature data for birds and mammals, nicarbazin posed both an acute risk 

(RQ = 1.4 for mortality) and chronic risk (RQ >500 for reproductive/chronic effects) to non-target 

listed and non-listed birds. This is not unexpected given its intended use as a bird reproduction 

inhibitor. At 1% of the diet, the chronic risk (RQ  5) still exceeded the Level of Concern (LOC). 

Currently, two labels (OvoControl P: EPA Registration No. 80224-1 and SLN Registration No. 

15000-1 (for Puerto Rico only)) are registered as a control agent (treated bait) for pigeons, with use 

limited to urban communities. Based on an application rate for flocks of 2,400 pigeons, more than 

10,000 pounds of the OvoControl P control agent, containing nearly 55 pounds of nicarbazin, will 

be applied at each treatment site. The number of treatment sites per urban area, or treatment density, 

is undefined. 

The formation of the vitelline membrane is common in animals, and the mode of action of 

nicarbazin is to reduce the viability and hatchability of eggs by interfering with the formation of the 

vitelline membrane. Therefore, reproductive effects in animals other than birds, including aquatic 

animals, are possible. However, no adequate studies that evaluated reproductive effects of 

nicarbazin in species other than birds have been submitted or identified in the open literature. 

Exposure to aquatic environments may occur if nicarbazin is used in close proximity of water, or 

through feces of target animals because nicarbazin appears to pass through birds largely unmetabolized. In addition, the nicarbazin components DNC and HDP, present in pigeon feces, are 

stable to hydrolysis. HDP is soluble in water, whereas DNC has a calculated Koc of 1650 and log 

Kow of 3.6. Thus, with continuous feeding, biomagnification and food-chain exposure to predators 

is possible.

Based on the mode of action and the potential exposures, data that allow for toxicity thresholds for 

reproductive effects to be defined are critical for risk assessment, including: 

x Fish full-life cycle (OCSPP guideline no. 850.1500) 

x Aquatic invertebrate life-cycle (OCSPP guideline no. 850.1300); 

x Chronic sediment toxicity (Non-guideline). 
4

Since DNC and HDP essentially work as a toxicant and synergist, respectively, data on both 

chemicals together will likely result in the most conservative analysis. However, studies of DNC 

with and without HDP would allow for an evaluation of the toxicity enhancement of HDP on DNC. 

Therefore, if there are differences in the environmental fate, metabolism, and exposure potential of 

the two chemicals, then the resulting differences in the risk profile can be described only if data on 

each component are available. Past assessments have also noted these data gaps. 

In addition, acute toxicity to aquatic organisms using the chemicals together is not known and 

toxicity to aquatic plant species in general is not known. Although nicarbazin has not shown high 

acute toxicity to other organisms, these data are needed for risk assessment if there is potential 

exposure to aquatic and saltwater environments. The freshwater species acute toxicity data can be 

used as a surrogate for the saltwater species. No toxicity data is available for terrestrial plants or 

terrestrial invertebrates; however, based on the current use pattern and available information, 

additional data is not needed at this time. 

Data Needs 

The specific recommended studies are summarized in Tables 1 and 2. For the acute aquatic 

freshwater invertebrate and fish studies listed in Table 1, acceptable studies already have been 

submitted for the individual nicarbazin components, but testing is recommended in these same 

species for the nicarbazin complex (DNC + HDP). The submitted ecotoxicity studies conducted 

with DNC and HDP are discussed in Table 7 and 8 below.

Table 1: Recommended Ecotoxicity Guideline and Non-Guideline Studies for Nicarbazin 

OCSPP 

Guideline Study 

Study 

Description Test Species Test Material 

Aquatic 

850.1010 Freshwater invertebrate 

acute toxicity 

Waterflea 

(Daphnia magna) Nicarbazin 

complex 850.1075 Freshwater fish acute 

toxicity 

e.g., Rainbow trout (Oncorhynchus mykiss)

or Bluegill sunfish (Lepomis macrochirus)

850.1300 Freshwater invertebrate 

life-cycle D. magna

DNC; 

and

Nicarbazin 

complex 

850.1500 Freshwater fish full lifecycle 

e.g., Rainbow trout 

(O. mykiss)

Non-Guideline Chronic Sediment 

Toxicity

Midge (Chironomus dilutes); freshwater 

amphipod (Hyalella azteca); and estuarine 

amphipod (Leptocheirus plumulosus)

850.4400 Aquatic vascular 

plant toxicity Duckweed (Lemna spp.) 

850.4500 Aquatic non-vascular 

plant toxicity

3 algal species 

850.4550 Cyanobacteria 

Terrestrial 

850.2100 Avian acute oral toxicity 

with passerine species 

Passerine species (e.g., house sparrow (Passer 

domesticus), zebra finch (Taeniopygia guttata), 

red-wing blackbird (Agelaius phoeniceus);

canary (Serinus canaria))

Nicarbazin 

complex 

(As Current 

Product; 

850.2300 Avian reproduction OvoControl P) Currently being conducted by registrant; 

(protocol review D424098, USEPA 2015b)
5

Despite its history of use in the poultry industry, little is known about the environmental fate of 

nicarbazin (WHO, 1998; Boxall et al., 2003a, b; EFSA, 2003). To conduct drinking water and 

ecological risk assessments for nicarbazin, EFED recommends the registrant submit seven (7) 

OCSPP environmental fate, transport and transformation test guideline studies. These guideline 

studies, by test material, are summarized in Table 2. Recommendations are consistent with 

previous risk assessments, data evaluation records, and responses to data waiver requests 

(DP312669, DP313794; USEPA, 2005a and b; and DP328803; USEPA, 2007a). 

Table 2: Recommended Environmental Fate, Transport and Transformation Guideline Studies 

OCSPP 

Guideline 

OCSPP Guideline 

Description Comments Test Material 

835.1230 Adsorption/ Desorption Batch equilibrium DNC; HDP; and 

835.1240 Leaching None Nicarbazin complex 

835.2120 Hydrolysis 

Will be used to evaluate 

the need for fish BCF 

study. 

Nicarbazin complex 

835.2240 Aqueous Photolysis 

Chemical properties 

indicate nicarbazin is 

likely to photolyze in 

water. DNC; HDP; and

835.4100 Aerobic Soil Metabolism None Nicarbazin complex 

835.4300 Aerobic Aquatic Metabolism None 

835.4400 Anaerobic Aquatic 

Metabolism None 

850.1730 Fish bioconcentration

A fish bioconcentration 

study is needed based on 

the high Kow of DNC 

(MRID 46416410). 

DNC; and 

Nicarbazin complex 

850.6100 Analytical methods in soil Must include ECM and 

ILV DNC; HDP; and 

Nicarbazin complex 850.6100 Analytical methods in water Must include ECM and 

ILV 

830.7550 

830.7560 

830.7570 

Octanol-Water Partitioning 

(Kow) Study 

Will be used to evaluate 

the need for fish BCF 

study. 

Nicarbazin complex 

Abbreviations: ECM = environmental chemistry methods; ILV = independent laboratory validation 

Label and Use Clarification Issues 

To better understand the manner in which nicarbazin is used or intended to be used would be 

beneficial for the subsequent risk assessment, especially for modeling purposes. The following 

information would help the Agency conduct a realistic risk assessment: 

x Clarify the term “urban areas.” Although the labels provides examples of site types (e.g.,

office parks, malls, etc.), in this context, how are “urban areas” identified? For example, are 

these use sites limited to within an urban area as defined by the U.S. Census Bureau?1

 See 

footnote below for more information about the U.S. Census Bureau classification. 

1 https://www.census.gov/geo/reference/urban-rural.html
6

x Clarify the number of treatment sites within the urban area, or define the maximum 

treatment density. 

x Usage data (none are available at this time). “Usage” is the number of lbs of the active 

ingredient used, typically on an annual basis, over the course of several years. Details on 

where this use occurs geographically, what sites represent what portion of overall usage, 

average and maximum application rates, etc., are also useful. 

x Maximum and typical flock count. The product application rate is based on an estimated 

flock count, which must be performed just prior to the intended time of application. The 

product labels do not limit the total amount of product to be used daily or annually at a 

given site. The labels provide examples of the application rate for different flock sizes, up to 

2,400 pigeons, but there is no explicit information about the maximum number of pigeons to 

be treated at any one site. It would also be useful to get an idea of the typical flock size or 

range of sizes applicators are attempting to control with a given application method (e.g.,

bait pans, mechanical feeders, etc.). 

2. Introduction

Nicarbazin was previously assessed at the time of the Proposed Registrations of OvoControl G for 

Geese in 2005 (DP312669, DP313794; USEPA, 2005a and b), and OvoControl P for pigeons on 

2007 (DP328803; USEPA, 2007a), as well as a Section 24c risk assessment on pigeons in Hawaii in 

2007 (DP344692; USEPA, 2007c), and a new use risk assessment for non-native hybrid, domestic 

and Muscovy ducks completed in 2007 (DP340973, DP335890; USEPA, 2007b). In addition to 

risk assessments that were completed, supplemental reviews and follow up waiver requests have 

also been completed for nicarbazin (DP363859, DP363860, USEPA 2009; DP372345, DP372348, 

DP349126, USEPA 2010; DP396672, USEPA 2011; D400098, USEPA 2012; DP415695, USEPA 

2014a).

a. Mode of Action 

Nicarbazin (C19H18N6O6, MW 426.38 g/mol) is a 1:1 complex of two compounds, 4,4'-

dinitrocarbanilide (DNC, 70.89% by weight) and 4,6-dimethyl-2-pyrimidinol (HDP, 29.11% by 

weight). DNC is considered to be the active component, and HDP aids in its absorption. The 

potency of DNC is reported to be increased tenfold when it is mixed with HDP (Chapman 1994). 

Nicarbazin is fed to pigeons to reduce the viability and hatchability of eggs by interfering with the 

formation of the vitelline membrane, which separates the egg yolk and the egg white. 

Historically, nicarbazin has been used since the mid-1950s as an anticoccidial agent to control 

intestinal protozoan parasites in the poultry industry. The Federal Drug Administration (FDA) 

currently approves the use of nicarbazin as a 125-ppm food additive for broiler chickens, but not for 

layers2

.

2 http://www.accessdata.fda.gov/scripts/animaldrugsatfda/details.cfm?dn=009-476
7

Figure 1: Chemical structures of HDP (left) and DNC (right)3.

3. Use Characterization

There are no agricultural pesticidal uses for nicarbazin. Through the OvoControl P label (EPA Reg. 

No: 80224-1), nicarbazin is currently registered for use as a ready-to-use control agent (treated bait) 

for pigeons. Limited to urban areas, specific use sites include: office parks, malls, institutions, 

bridges, airports, and other commercial and industrial buildings or structures. OvoControl P may be 

applied via managed bait stations to flat rooftops, or other flat paved or concrete surfaces in secured 

areas that limit public access. Nicarbazin is not registered for use in Guam, American Samoa, 

Northern Mariana Islands, and the U.S. Virgin Islands. A Special Local Needs (SLN) 24(c) (EPA 

SLN No. 150001) was approved for Puerto Rico in May, for distribution and use of OvoControl P 

within Puerto Rico until January 15, 2020. Prior to application, applicators within Puerto Rico must 

contact the Pesticides Regulatory Office of the Puerto Rico Department of Agriculture to obtain a 

permit. The label follows the OvoControl P label (EPA Reg. No: 80224-1), with some additions 

specific to Puerto Rico. There are restrictions regarding application in areas of non-target birds cooccurrence (i.e., Scaly-naped pigeon (Patagioenas squamosa), Plain pigeon (Columba inornata 

wetmorei), Ringneck dove (Streptopelia risoria), Zenaida dove (Zenaida aurita), White-winged 

dove (Zenaida asiatica) and Common Ground dove (Columbina passerina)), and some urban areas 

(Baxter Company Pharmaceuticals Installations located in Guayama, and Cabo Rojo and the 

delimited area for the protection of the Plain Pigeon at Cidra, Comerio, Caguas, Cayey and Aguas 

Buenas municipalities). 

As an anticoccidial agent, nicarbazin has been used to control intestinal protozoan parasites in the 

poultry industry since the mid-1950’s. The Federal Drug Administration (FDA) approves the use of 

nicarbazin as a food additive for broiler chickens, but not for layers4

.

Unlike use tables that typically summarize maximum use rates, Table 3 summarizes the year-round 

minimum application rate scenario by urban use sites. This is provided because the OvoControl P 

3 http://pubchem.ncbi.nlm.nih.gov/compound/Nicarbazin#section=Top

4 http://www.accessdata.fda.gov/scripts/animaldrugsatfda/details.cfm?dn=009-476
8

labels do not limit the maximum daily or annual application rates. Pursuant to the labels, once 

pigeons are conditioned to the daily baiting program, feeding must continue daily during the entire 

nesting season. Depending on the climatic zone and habitat, nesting, and corresponding baiting 

could last year-round. The minimum single daily application rate on the labels are 2 ounces of 

product for every 10 pigeons. The maximum daily application rate is not specified on the labels; 

however, the labels provide an example of bait for 2,400 pigeons. For the example rates provided 

on the labels, the daily application rate could range from 0.01 ounces (oz.) of active ingredient (a.i.) 

to 2.4 oz. a.i. per day, or more. Annual application rates could exceed 10,000 pounds treated bait, or 

54 lbs active ingredient. However, usage data is not currently available for nicarbazin (USEPA, 

2015a).

Table 3: Use summary of nicarbazin for OvoControl P labels (EPA Reg. No. 80224-1 & SLN 

No. 150001). 

Use Sites

(Urban)

Minimum Single 

Application Rate Application 

Interval 

(daily) 

Maximum 

Number of 

Annual 

Applications 

Minimum Annual 

Application Rate 

(oz. product/ 

10 pigeons) 

(oz. a.i./10 

pigeons 

(oz. product/ 

10 pigeons) 

(oz. a.i./ 

10 pigeons) 

Office Parks 

2 0.01 1 365 730 3.65 

Malls 

Institutions 

(e.g. hospitals and 

schools) 

Bridges 

Airports 

Commercial 

buildings or 

structures 

Industrial 

buildings or 

structures 

4. Conclusions from Previous Risk Assessments

a. Ecological Risk Assessment 

A number of ecological risk assessments have been conducted on nicarbazin. The conclusions from 

the past assessments are summarized in Figure 2 and Table 4 below.
9

Figure 2: Graphic Summary of Potential Risks of Current Uses of Nicarbazin 

Table 4: Evidence of Risk to Taxonomic Groups from Assessed Nicarbazin Uses 

Conclusion: No Risks of Concern 

Certainty: High 

Conclusion: Risks of Concern Identified 

Certainty: High 

Terrestrial Invertebrates: Minimal potential 

for exposure, no data is needed. 

Terrestrial plants: Minimal potential for 

exposure, no data is needed. 

Birds (surrogates for reptiles and terrestrial-phase 

amphibians): Based on very limited guideline and literature 

data for environmental fate and effects, acute risk (RQ = 1.4 for 

mortality) and chronic risk (RQ >500 for reproductive/chronic 

effects) to non-target listed and non-listed birds. Based on the 

information available, at 1% of the diet, the chronic risk (RQ 

5) still exceeded the LOC. Adverse effects may not be limited 

to egg production and hatching, but may also include other 

effects yet to be evaluated in other bird species. 

Conclusion: No Risks of Concern 

Certainty: Low 

Conclusion: Risks of Concern Identified 

Certainty: Low 

Fish & Aquatic Invertebrates: Acute effects in fish 

(surrogates for aquatic-phase amphibians) and aquatic 

invertebrates are not anticipated based on submitted data and 

dissolved-phase exposures; however, the greater exposures in 

sediments cannot be assessed due to lack of chronic sediment 

toxicity data. Adverse reproductive effects in exposed egglaying aquatic organisms are anticipated, based on the mode of 

action in birds. These effects cannot be quantified due to lack 

of reproduction data. 

Aquatic Plants: No toxicity data is available for aquatic plants; 

however, there is the potential for exposure to occur. Data is 

needed to evaluate and characterize the risk potential.

Mammals: Mammalian toxicity data are available; however, 

the registrant did not submit guideline studies. The acute and 

reproductive/chronic data available to the Agency have not 

been assessed in past assessments. There is the potential for 

both primary and/or secondary exposure to occur. Any relevant 

information available to the Health Effect Division (HED); 

EFED will review and consider it. 
10

b. Drinking Water Exposure Assessments 

EFED has not conducted a drinking water exposure assessment for nicarbazin, labeled as 

OvoControl P. 

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 nicarbazin (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. The 

aquatic life benchmarks have not been published for nicarbazin. 

Nicarbazin is not identified as a cause of impairment for any water bodies listed as impaired under 

section 303(d) of the Clean Water Act5

. No Total Maximum Daily Load (TMDL) criteria have been 

developed for nicarbazin 

5. Environmental Fate and Transport Characteristics

Despite its history of use in the poultry industry, little is known about other effects or the 

environmental fate of nicarbazin (WHO, 1998; Boxall et al., 2003; EFSA, 2003). Environmental 

fate and transport characteristics have been explored in several previous risk assessments 

(DP312669, 313794, 2005; and DP328803, 2007a). Chemical, physical, and environmental fate and 

transport properties presented in this problem formulation were used in these previous assessments, 

and are reiterated below. 

a. Physical Properties 

Nicarbazin (C19H18N606, MW 426.38) is a 1:1 complex of two compounds, 4,4'-dinitrocarbanilide 

(DNC, 70.89% by weight) and 4,6-dimethyl-2-pyrimidinol (HDP, 29.1 1% by weight). It is 

crystalline or a yellow powder. 

The nicarbazin complex is characterized as “inherently very stable material”, where only acidic or 

basic conditions led to “some” degradation, into the DNC and HDP components (MRID 46416407). 

The degradation of the nicarbazin complex is likely biologically mediated since DNC and HDP are 

detected in organism’s feces. DNC and HDP have differing physical properties such that once in 

the environment, they will likely have different fate profiles. 

5 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885.
11

DNC, also known as N,N'-bis(4-nitropheny1)urea or BNPU, has the formula C13H10N4O5 and 

molecular weight of 302.25 g mol-1. Its low solubility has been reported as 20 ppb (EFSA, 2003), 

28 ppb (pH5), 52 ppb (pH7) and 76 ppb (pH9). It has a log octanol-water partition coefficient (log 

Kow) of 3.6 which suggests that DNC could bioaccumulate. 

HDP, also known as 4,6-dimethyl-2(1 H)-pyrimidinone, has the formula C6H8N2O, and molecular 

weight of 124.14 g mol-1. HDP melts at approximately 200 to 205°C, and has a log octanol-water 

partition coefficient (log Kow) of -0.94. Its solubility in water has been reported as greater than 

10,000 ppm (EFSA, 2003). HDP’s log Kow of -0.94 indicates that it is highly hydrophilic. 

Table 5 summarizes the physical/ chemical properties of nicarbazin and its constituents DNC and 

HDP. There are a number of data gaps, including data for solubility of the nicarbazin complex, 

octanol-water partition coefficient (log Kow), vapor pressure, and Henry's Law constants. 

Table 5: Physical/Chemical properties of nicarbazin complex, DNC and HDP. 

Physical 

Property 

Nicarbazin 

Complex DNC HDP Source 

(MRID) 

CAS Reg 

No. 330-95-0 587-90-6 108-79-2 -- 

Molecular 

weight,

(g mol-1)

426.38 302.25 124.14 

Molecular 

Formula C 19H18N606 C13H10N405 C6H8N20

Structure NA

Melting 

point

(°C) 

265-275 312 200-205 

UV/VIS 

absorption 

Max

(nm) 

298 No data 300 

Aqueous 

solubility 

(ppm) 

No data 

pH5: 0.028 

pH7: 0.052 

pH 9: 0.076 

>10,000 (EFSA, 2003) 

logKow No data 3.6 - 0.94 46416410 

Vapor 

Pressure No data No data No data -- 

Henry's 

Law

constant 

No data No data No data -- 

Hydrolysis No data Stable Stable 46445305 

Abbreviations: °C = degree Celsius; g = grams; mol = mole; NA = not applicable; nm = nanometers; ppm = parts per 

million 
12

b. Degradation Characteristics

Little is known about the environmental fate and transport characteristics of the nicarbazin 

complex, or its components DNC and HDP. Few OSCPP guideline compliant studies have been 

submitted to adequately characterize the environmental fate, and no new environmental fate studies 

have been submitted since the previous risk assessments. Table 6 summarizes the chemical 

properties and environmental fate parameters of the nicarbazin complex and the DNC and HDP 

components, when data are available. 

Table 6: Environmental fate characteristics of nicarbazin complex and its components, DNC 

and HDP. 

Parameter Value Description Source 

(MRID) 

Persistence

Hydrolysis 

half-life (d) 

Complex: No data 

DNC: Stable 

HDP: Stable 

MRID did not evaluate 

the nicarbazin complex. 46445305 

Aqueous photolysis half-life (d) No data Waiver denied 464164452)

Soil photolysis half-life (d) No data -- --1)

Aerobic soil metabolism 

half-life (d) Invalid data Unacceptable 46416446 

Anaerobic soil metabolism 

half-life (d) No data -- --1)

Aerobic aquatic metabolism 

half-life (d) No data -- --1)

Anaerobic aquatic metabolism halflife (d) No data -- --1)

Mobility

Freundlich soil-water partition 

coefficients (KF);

organic carbon-normalized 

Freundlich coefficients (KFOC)

Complex: No data 

DNC: 1650 

HDP: No data 

Unacceptable:

Value calculated 464164473)

Field Dissipation

Terrestrial field dissipation: 

half-life (d); leaching depth 

28 days 

0-15 cm -- 464453064)

Terrestrial field dissipation: 

half-life (d); leaching depth 

301 days 

0-15 cm -- 464164494)

Aquatic field dissipation 

half-life (d) No data -- -- 

Fish Bioconcentration

Fish bioconcentration factors; 

depuration rate (d) No data Waiver denied 464971022)

Abbreviations: a.i. = active ingredient; d = days; oz. = ounces 

 Notes: 

1) No OCSPP guideline study submitted. 
13

2) MRID represents a waiver request; subsequently denied. 

3) Unacceptable data; value presented for DNC was calculated using EPISuite software. 

4) Supplemental data used for characterization purposes only. 

Of the five (5) OCSPP guideline studies submitted for nicarbazin, only one MRID is acceptable, 

two are supplemental, and two are unacceptable. From the only acceptable guideline compliant 

study (hydrolysis half-life), both DNC and HDP are classified as stable and do not undergo 

hydrolysis in sterile water at pH 5 to 9 (MRID 46445305). 

A study of mobility in soil (MRID 46416447) was classified as unacceptable because of the 

obsolete methodologies and inadequate documentation (DP312669, 2005a and b). For purposes of 

aqueous fate modeling in previous risk assessments (DP312669, 313794; 2005a and b; and 

DP328803, 2007a), EFED used EPISuite software to estimate the organic carbon partitioning 

coefficient (Koc) at 1650 mL/kg for the DNC component. 

Two supplemental field studies were reviewed as non-guideline studies due to numerous deviations 

from the terrestrial field dissipation guideline. One field study (MRID 46445306) was conducted in 

a greenhouse using confined bare soil flats of silt loam (Greenfield, IN). The soil flats were 

confined in plastic bags to reduce volatilization, and lined with aluminum foil to reduce leaching. 

Approximately 80 to 102% of the radioactivity applied was accounted for over a 1-year span, with a 

slight downward trend. The observed DT50 was about 28 days, however 28-30% of the applied 

radiation was still present as nicarbazin at 364 days, indicating that first-order kinetics were not 

followed.

The second field study (MRID 46416449 and 46416446) was conducted in a 3-ft diameter enclosed 

bare plot of silt loam soil in Greenfield, Indiana. Nicarbazin fortified soil, consisting of milled, airdried top soil (3 inches) blended with non-sterile greenhouse potting soil and chicken excreta, was 

incorporated at a target application rate of 2.47 kg a.i./ha in a single 3-ft diameter (7.07 sq ft) test 

plot surrounded by a metal culvert extending 38 cm into the soil and 23 cm above the soil. The total 

recovery of radioactivity from the soil (measured as DNC) was initially 111.3% at time-0 and 

ranged from 112.3-142.6% throughout the remainder of the study period through 377 days posttreatment. The reviewer-calculated half-life of 14C nicarbazin in soil was 301 days (r2 = 0.80),

calculated using log-linear regression analysis. A DT90 value was not determined. At the end of the 

study period, 377 days post-treatment, the total carryover of residues of nicarbazin was 47.3% of 

the applied. 

The major route of dissipation of nicarbazin under terrestrial field conditions is likely 

transformation; however, samples were not analyzed for degradates. Loss from other dissipation 

routes (leaching, volatilization) can all be assumed to be minimal because the material balance did 

not decrease below the time-0 recovery of radioactivity. Dissipation due to runoff was prevented 

due to the design of this study (culvert around soil plot). Runoff of DNC and HDP, in either the 

dissolved phase or attached to soil particles or feces is expected to be a major route of dissipation 

and transport to water bodies. 

From the available information, it can be deduced that the DNC degrades slowly in soil with a halflife of about 300 days, does not volatilize substantially, or leach through the soil. It may run-off 

with storm water when sorbed to soil particles. 
14

c. Study Waiver requests 

The registrant has requested waivers for two studies associated with the initial registration of 

nicarbazin; both have been denied. A request for a waiver of aqueous photolysis (MRID 46416445) 

was denied because there is evidence that nicarbazin absorbs light in the visible range, which makes 

photolysis a possible route of degradation (DP312669, 2005). 

A waiver request for the fish bioaccumulation study (MRID 46497102) was also denied pending 

information on the log Kow of nicarbazin (the complex), and a study of its hydrolysis behavior 

(DP312669, 2005).

d. Degradates 

Degradates have not been identified in any of the submitted environmental fate studies. However, 

new studies are being requested, and if degradates are observed in any of the requested 

environmental fate studies in great enough quantities; it could potentially trigger the need for 

degradate toxicity data for those identified degradates. If we do not get adequate degradate data, 

EFED will have to make conservative assumptions that could result in greater risk concerns. 

6. Receptors

Toxicity endpoints from currently available studies on nicarbazin are presented in Table 7 through 

Table 8 below.

For the available aquatic studies DNC and HDP were tested separately. HDP is practically nontoxic to freshwater fish and invertebrates on an acute basis. Acute toxicity tests for freshwater fish 

(warm water and cold water species) and daphnids using DNC were conducted at or above the limit 

of solubility. There were no mortality or sublethal effects reported for the freshwater fish studies, 

however, in both the DNC and HDP bluegill studies, smaller than recommended fish were used and 

those studies were classified as “supplemental” rather than “acceptable.” For daphnids, 

mortality/immobilization and sublethal effects (lethargy) were both observed in multiple test 

concentrations in the DNC study, minimal effects were observed in the HDP study. No acute 

toxicity data are available for estuarine/marine fish or invertebrates; no chronic toxicity data are 

available for any aquatic animals or plants. 

For terrestrial organisms, the test material was the nicarbazin complex. Nicarbazin was practically 

non-toxic to mammals on an acute oral basis. The data indicate that nicarbazin is slightly to 

practically non-toxic to birds on an acute dietary basis and practically non-toxic on an acute oral 

basis. No mortality or clinical signs of toxicity were observed in the available avian acute oral 

toxicity study. Some clinical signs of toxicity (mortality, and sublethal effects) were observed in 

both dietary studies, with greater effects observed in the mallard study. Although this chemical is 

registered as an egg-hatchability control agent, no guideline avian reproduction studies have been 

submitted to the Agency yet. Non-guideline studies and numerous open literature studies have been 

submitted on multiple species including chickens (Gallus gallus), and Japanese quail (Coturnix

japonica). However, the data previously submitted and reviewed do not provide sufficient 

information on reproductive endpoints to meet guideline requirements (see DP363859, DP363860, 

USEPA 2009; DP372345, DP372348, DP349126, USEPA 2010; DP396672, USEPA 2011; 
15

DP400098, USEPA 2012; and DP415695, USEPA 2014a for more detailed analysis). The twogeneration mammalian reproduction study using a 3:1 ratio of DNC:HDP showed no effects on 

adult rats, but some effects on offspring; however, these were not considered significant to 

reproduction. In the developmental study there were increased mortality to adults and decreased 

food intake and body weight gain of females at the high test concentration. In addition, the fetal 

body weight was also decreased at the highest test concentration. The fetuses of the dams in the 

highest test concentration also showed signs of delayed ossification, hyperplastic and bent ribs (4 

fetuses), sacralization of the 6th or 7th lumbar vertebrae (two fetuses), cleft palate (two in the same 

litter), subcutaneous odema (three in the same litter), hydronephrosis (five fetuses), cryptorchismus 

(one fetus), and remained Merkel’s diverticulum (one fetus). No toxicity data are available for 

honeybees or terrestrial plants. 

a. Effects to Aquatic Organisms 

Table 7: Summary of the Most Sensitive Toxicity Data Currently Available for Aquatic 

Animals Exposed to Nicarbazin. 

Test Species 

Test

Substance 

(% a.i.)

Acute Toxicity 

LC50/EC50

(mg a.i./L) 

(Toxicity Classification) 

MRID

(Study Classification) 

Rainbow trout 

DNC 

(98% a.i.) >0.069 46416432 (Acceptable) 

HDP

(99.4% a.i.) 

>110 

(practically non-toxic)

46416431 

(Acceptable) 

Bluegill sunfish 

DNC 

(98% a.i.) >0.072 46416434 (Supplemental) 

HDP

(99.4% a.i.) 

>122

(practically non-toxic) 

46416433 

(Supplemental) 

Waterflea

DNC 

(98% a.i.) >0.093 46416436 (Acceptable) 

HDP

(99.4% a.i.) 

>107 

(practically non-toxic) 

46416435 

(Acceptable) 
16

b. Effects to Terrestrial Organisms 

Table 8: Summary of the Most Sensitive Acute and Chronic Toxicity Data Currently Available 

for Terrestrial Animals Exposed to Nicarbazin. 

Test Species 

Test

substance 

(% a.i.) 

Acute Toxicity Chronic Toxicity 

LD50

(mg a.i./kg bw) 

(Toxicity 

Classification) 

LC50

(mg a.i./kg diet 

(ppm))

(Toxicity 

Classification) 

MRID

(Study

Classification) 

NOAEC/ 

LOAEC 

(mg a.i./kg diet 

(ppm)) 

(Endpoints) 

MRID

(Study

Classification) 

Bobwhite Quail 

(Colinus 

virginianus)

Nicarbazin 

complex 

(>99% a.i.) 

>2250

 (practically 

non-toxic)

>5720

(practically 

non-toxic)

46416426 

(Acceptable) 

&

46416427 

(Acceptable) ND

Mallard Duck 

(Anas

platyrhynchos)

Nicarbazin 

complex 

(>99% a.i.) 

ND 3680

(slightly toxic)

46445302 

(Acceptable) 

Laboratory rat 

(Rattus 

norvegicus)

Acute: 

>95% a.i.; 

Chronic:

3:1 ratio of 

DNC:HDP 

(Repro.) 

1:1 ratio of 

DNC:HDP 

(Develop.) 

>10,000 

(practically 

non-toxic)

-- 46416413 

(Acceptable) 

400/>400 

(No effects on 

adults; decreased 

bw F1b; fewer 

pups in F2a & F3a

litters, but not in 

F2b & F3b litters) 

46416422 

(Acceptable) 

Reproductive 

200/600 

(Increased adult 

mortality; 

decreased bw 

gain; decreased 

fetal bw; fetuses 

showed add’l 

physical effects) 

46416421

(Acceptable) 

Developmental 

ND = No Data; -- = Not applicable 

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 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. 
17

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

Monitoring System (AIMS)6

, and the EPA Incident Data System (IDS, Aggregate Incident Reports 

database) were conducted on April 7, 2015 for nicarbazin. There were no reported incidents in the 

EIIS, AIMS, or the Aggregate Incident Reports databases for nicarbazin. 

It should be noted, that the lack of reported incidences should not be construed as the 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. Incidents often are not seen, due to scavenger removal of carcasses, decay in the field, or 

simply because carcasses may be hard to see on many sites and/or few people are systematically 

looking. Poisoned animals may also move off-site to less conspicuous areas before dying. 

Incidents may not get reported to appropriate authorities capable of investigating the incident for a 

variety of reasons including the finder may not know of the importance of reporting incidents, may 

not know who to call, may not feel they have the time or desire to call, or may hesitate to call 

because of their own involvement in the kill. Incidents reported may not get investigated if 

resources are limited or may not get investigated thoroughly, with residue analyses, for example. 

Also, if kills are not reported and investigated promptly, there will be little chance of documenting 

the cause, since tissues and residues may deteriorate quickly. Reports of investigated incidents 

often do not get submitted to EPA, since reporting by states is voluntary. 

7. Exposure Pathways of Concern

In order for a chemical to pose an ecological risk, it must reach ecological receptors in biologically 

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

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

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

of exposure for ecological receptors, and a feasible route of exposure. The assessment of ecological 

exposure pathways, therefore, includes an examination of the sources and potential migration 

pathways for constituents, and the determination of potential exposure routes (e.g., ingestion, 

inhalation, dermal absorption). 

Chemical properties and the registered OvoControl P use patterns indicate that non-target species, 

both terrestrial and aquatic, may be exposed to the nicarbazin complex, and the DNC and HDP 

components.

A conceptual model discussing and illustrating exposure pathways had been developed in several 

previous risk assessments for nicarbazin (DP312669, 313794, 2005; and DP328803, 2007), which 

remain valid. Exposure pathways presented in this problem formulation were used in these 

previous assessments, and are reiterated below. 

6

 http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm 
18

a. Background 

Applications of bait will be made directly to terrestrial environments, either in bait pans, bowls or 

trays, or by broadcast application via hand or mechanical feeders onto rooftops, other flat paved or 

concrete surfaces (only). As applied according to the proposed labels, nicarbazin bait may be 

available to non-target organisms. On the labels there is precautionary language concerning nontarget species: “Do not apply more OvoControl P than the pigeons will eat in a single feeding, as 

this may result in non-target species' exposure to leftover bait. Do not apply in urban areas where 

the product may be consumed by federally listed Threatened and Endangered birds. Daily 

observations for non-target species must be conducted for the entire five (5) to fourteen (14) day 

conditioning period after feeding begins. Do not apply if non-target feeding persists and/or cannot 

be prevented. English house sparrows (Passer domesticus) and European starlings (Sturnus

vulgaris) are exempt from this restriction. It is a violation of state and federal law to intentionally 

feed treated bait to non-target species, including protected species.” However, data have not been 

provided to demonstrate that pigeons will exclude non-target animals from feeding and consume all 

bait that is applied. The primary source of exposure of non-target terrestrial animals is likely to be 

consumption of the formulated food bait. Consumption of eggs and tissues of target and non-target 

animals that have eaten bait is a potential source of exposure to predators and scavengers. As 

discussed above, biomagnification and food-chain exposure of predators is possible if exposure is 

continuous. Dermal and inhalation routes of exposure occur for some pesticides but are not likely to 

be significant for the grain-based nicarbazin food bait. Potential exposure routes are discussed in 

the following sections and include potential exposures to terrestrial and aquatic environments. 

b. Potential Exposure to Terrestrial Wildlife 

Data are available demonstrating that non-target species of birds and mammals consumed 

nicarbazin bait in a field study designed to test efficacy in Canada geese (not a currently registered 

use) (Bynum et al., 2005 [MRID 46497103]). Although the application conditions in the field 

study were different than actual label-compliant use for the control of pigeons, it can be concluded 

that direct exposure to the nicarbazin complex by non-target species through the consumption of 

treated bait is not precluded by any characteristics of the bait itself (i.e., the bait can be consumed 

by a variety of organisms). 

The degree to which non-target species may be directly exposed to nicarbazin depends upon, but is 

not limited to, the applicator’s compliance with label use directions and prohibitions, the presence 

of mixed flocks, the amount of treated bait consumed, and if the unconsumed bait is adequately 

monitored and removed from the treatment site. EFED will consider the extent to which current 

product labeling could impact the exposure of non-target wildlife through direct consumption of 

bait. 

In addition, nicarbazin and/or DNC may be indirectly released into terrestrial and aquatic 

environments through defecation by pigeons and non-target animals or by accidental release or 

spillage of unconsumed bait where it may accumulate and be available to soil organisms or in 

puddles used for drinking water by wildlife. Based on the product formulation, the inhalation 

exposure pathway is not a potential exposure pathway of concern, and no further analysis was 

needed. 
19

c. Secondary Exposure by Predators and Scavengers 

Secondary exposure is also possible (EFSA 2003), but the extent to which this may occur is 

unknown. Nicarbazin and DNC released into the terrestrial environment from bait or feces will be 

available to soil macroinvertebrates for uptake or consumption. Terrestrial animals that feed on soil 

macroinvertebrates may receive exposure via this pathway. Secondary exposure may also occur to 

predators and scavengers consuming tissues and/or eggs of animals that have ingested bait. This 

exposure may occur in both the aquatic and terrestrial environment and may raise the potential for 

risk to species that consume eggs of target and non-target birds (e.g., birds and reptiles). As 

discussed above, biomagnification and food-chain exposure of predators is possible if exposure is 

continuous.

d. Potential Exposure to Aquatic Environments 

The proposed labels prohibits application to areas within 20 feet of water bodies, which may restrict 

incidental deposition in water from application of Ovocontrol P. However, the bait trays or bowls 

are made of durable plastic or metal, and are perforated to allow for drainage, and depending on the 

use site there could be exposure to water bodies. The labels do note that if rain is a factor, the bait 

should be located under partial cover or a canopy, and the bait should not be applied where water 

may accumulate. Although the labels specifically prohibits application of nicarbazin bait to 

standing water, the presence, frequency, and size of areas with standing water are expected to vary 

throughout the year. Unless bait sites are monitored regularly throughout the application period, 

applicators may be unable to prevent incidental deposition of bait into standing water (e.g., from 

automated/mechanical feeders). Also, OvoControl P is registered for use on bridges and used on 

roof tops or other flat paved or concrete surfaces, which may drain into water bodies. Therefore, 

washoff or overflow from rainfall events may occur resulting in direct exposure to water bodies. 

DNC is expected to primarily partition to sediments in aquatic environments where it is expected to 

persist; therefore, potential reproductive effects to sediment organisms are of concern. 

DNC and HDP are not fully metabolized by target or non-target species. Thus, these unmetabolized components embedded in species feces are likely to be deposited to an array of objects. 

EFED plans to evaluate potential exposures to aquatic environments from: 1) direct deposition into 

receiving water body (e.g., registered use of OvoControl P on bridges); 2) deposition onto 

impermeable surfaces (e.g., rooftop, pavement, etc., typical of urban environments); and 3) 

deposition onto permeable surfaces representative of soils or turf matrices. EFED will examine 

these three exposure pathways to establish a range of estimated environmental concentrations 

(EECs).

e. Ecological Drinking Water Exposure Pathways 

The drinking water exposure pathway was screened using the SIP (Screening Imbibition Program, 

version 1.0) screening methods. As previously described the aquatic exposure of nicarbazin would 

likely occur through the DNC and/or HDP components, and therefore the SIP model was run for 

both components. For the DNC and HDP components, it was determined that drinking water 

exposure alone was is NOT a potential concern for mammalian species on an acute and chronic 

basis (Tables 9 and 11). For birds, it was determined that the drinking water exposure alone was 

also NOT a potential concern on an acute basis for the DNC component (Table 10); however, there 
20

was not enough data to preclude chronic exposure for either DNC or HDP components (Tables 10 

and 12). The HDP component of nicarbazin drinking water exposure alone was determined to be a 

potential pathway of concern for birds on an acute basis (Table 12). Outputs for the model are 

located in Appendix A. SIP is described in detail at: 

http://www.epa.gov/oppefed1/models/terrestrial/index.htm.

Table 9: SIP Mammalian Results (DNC component) 

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.013 0.013 

Adjusted toxicity value (mg/kg-bw) 7692 154

Ratio of exposure to toxicity 0.000 0.0001 

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals 

Drinking water exposure 

alone is NOT a potential 

concern for mammals 

Table 9: SIP Avian Results (DNC component) 

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.062 0.062 

Adjusted toxicity value (mg/kg-bw) 20025 0.00 

Ratio of exposure to acute toxicity 0.00 0.00 

Conclusion*

Drinking water exposure 

alone is NOT 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. 

Table 10: SIP Mammalian Results (HDP component) 

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 1720 1720 

Adjusted toxicity value (mg/kg-bw) 1730 154

Ratio of exposure to toxicity 0.994 11.18

Conclusion*

Exposure through drinking 

water alone is a potential 

concern for mammals 

Exposure through drinking 

water alone is a potential 

concern for mammals 

Table 11: SIP Avian Results (HDP component) 

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 8100 8100

Adjusted toxicity value (mg/kg-bw) 20025 0.000

Ratio of exposure to acute toxicity 0.405 0.000

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. 

There are substantial uncertainties concerning the ecological effects of nicarbazin, in part due to the 

extremely limited ecotoxicity data that are available. Reduction in egg hatchability is a primary 
21

concern for non-target birds that are exposed to nicarbazin; however other effects including 

mortality and reproductive effects in male birds have been recorded (Chapman 1994, EFSA 2003). 

Few data exist for reptiles (e.g., USDA/APHIS National Wildlife Research Center; Mathies and 

Miller 2005 and Primus et. al., 2003), which may also be affected if they consume bait or target 

birds. Folliculogenesis and the vitelline membrane are features common to egg laying birds, 

reptiles, amphibians, mammals, and aquatic animals including fish and invertebrates. However, the 

toxicity database for aquatic species, especially on a chronic exposure basis, is very limited. 

Therefore, the evaluation of risk to various taxonomic groups has been based on very limited 

toxicity data. 

8. Analysis Plan

Although the DNC and HDP components are practically non-toxic to freshwater fish and 

invertebrates on an acute basis, the reproductive toxicity of these individual components to fish and 

aquatic invertebrates are not known. The formation of the vitelline membrane is common to many 

animals, and the mode of action of nicarbazin is to reduce the viability and hatchability of eggs by 

interfering with the formation of the vitelline membrane. As discussed previously, the 

contamination of water bodies with nicarbazin and its components is possible given the vicinity of 

the home range, the size of the home range of pigeons relative water bodies, and the excretion of 

waste products. EFED concludes that reproductive effects in egg laying animals other than birds, 

include reptiles, terrestrial-phase amphibians, mammals, fish, aquatic-phase amphibians, and 

aquatic invertebrates, are possible. So that reproductive effects in other potentially exposed animals 

may be assessed, EFED recommends that the following studies be required: a fish full-life cycle 

(guideline no. 850.1500), an aquatic invertebrate life-cycle (guideline no. 850.1300), and chronic 

sediment toxicity (non-guideline) studies with DNC alone and the nicarbazin complex 

(HDP+DNC). These types of studies have also been identified as data gaps in previous 

assessments.

The nicarbazin assessment will be based on the following use presumptions, based on the current 

product labels: 

· bait will be applied daily for many weeks (up to 52 weeks in some areas) in specific urban 

areas inhabited by pigeons 

· spilled bait and bait not eaten by pigeons may pose a risk to diurnal and nocturnal non-target 

animals, if not cleaned up as specified on label 

· bait applied on the ground (“other flat paved or concrete surfaces” poses risks to more 

wildlife than does bait applied on suitable elevated sites (roof tops) 

· broadcast applications pose higher risks to non-target animals than do placements in trays or 

pans that are removed immediately after pigeons have fed 

 · the failure to define “urban” on the product labels allow widespread use and more potential 

non-target exposure 
22

a. Stressors of Concern 

i. Ecological Risk Assessment 

For the nicarbazin ecological risk assessment, the stressors of concern are nicarbazin, and the 

individual DNC and HDP components. 

ii. Drinking Water 

The EPA Office of Water has not made a determination regarding nicarbazin in water supply. 

EFED has not previously conducted a drinking water exposure assessment for nicarbazin, labeled as 

OvoControl P. However, EFED will consult with HED to determine if a drinking water exposure 

assessment will be needed for nicarbazin as a part of registration review, based on HED’s needs. 

A formal determination of the residues of concern for drinking water will be made prior to the 

conduct of the risk assessment. 

b. Measures of Exposure 

The degree to which non-target birds (surrogates for terrestrial-phase reptiles and amphibians), and 

mammals may be directly exposed to nicarbazin depends upon, but is not limited to, the presence of 

mixed flocks, the amount of treated bait consumed, and if the unconsumed bait is adequately 

monitored and removed from the treatment site. Precautionary language on the labels, to try and 

limit exposure to non-target animals; however, there is still the potential for non-target wildlife to 

be exposed through direct consumption of bait unless labels can preclude or severely limit the 

potential for non-target animals to gain access to baits. 

i. Terrestrial Exposure 

Exposure of terrestrial animals can occur via several pathways, including consumption of the food 

bait, consumption of birds or mammals that have eaten bait and contain residues in body tissues, 

and consumption of eggs laid by birds exposed to the food bait. Primary exposure will be based on 

the daily availability of the formulated 5000 ppm a.i. food bait. Literature sources will be searched 

for any available nicarbazin residues in body tissues and in eggs. As discussed above, 

biomagnification and food-chain exposure of predators may occur if exposure is continuous. 

For estimating direct exposure to the nicarbazin complex by non-target species, terrestrial and 

aquatic, exposures will be estimated using the bait concentration and estimated feeding rates of 

birds.

i. Aquatic Exposure 

Because of the potential unique exposure pathway to aquatic environments from DNC and HDP 

embedded in pigeon feces (described in Chapter 7, Exposure Pathways of Concern), EFED will 

explore methodologies to derive an area weighted application rate (e.g. lbs/acre). Unlike previous 
23

risk assessments, where the application scenario was representative of turf environments, the 

registration review aquatic risk assessment will evaluate potential exposures from applications only 

to rooftops, hard structures, and concrete and paved surfaces. EFED will estimate exposure 

concentrations using standard exposure models for both components separately. 

ii. Available Monitoring Data 

Despite its long history of use in poultry production, the presence of nicarbazin in water bodies has 

never been studied. Environmental exposure to aquatic environments from the use of nicarbazin in 

poultry production is possible through land disposal of litter and droppings from treated birds. 

Interest in the possible adverse effects of pharmaceuticals, including those used in veterinary 

medicine, has increased in recent years. Two papers identify nicarbazin as a high-priority for further 

research into its possible environmental effects (Boxall et al., 2003a and 2003b).

For the pesticidal use of nicarbazin, environmental exposure to aquatic environments could occur 

via pigeon feces, by accidental release or spillage of unconsumed bait, run-off from treatment areas, 

or displacement of bait applied to bridge surfaces. 

Nicarbazin 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 nicarbazin are available. 

c. Measures of Effect 

Measures of effect are based on the toxicity values generated in the guideline toxicity studies 

submitted by the registrant. When more than one value is generated (e.g., avian LC50), the most 

sensitive value is used for the screening assessment. For nicarbazin, guideline studies for various 

acute and reproductive/chronic toxicity data are lacking. When available and deemed appropriate 

for the assessment, toxicity values or qualitative descriptions presented in the literature are used to 

assess risk. 

Toxicity data presented in Section 6 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, 2007d), 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. 
24

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 nicarbazin in connection with the development of its 

final registration review decision for nicarbazin.

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 nicarbazin 

does not describe the specific ESA analysis, including effects determinations for specific listed 

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 nicarbazin 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 nicarbazin 

as part of completing this registration review. 

e. Endocrine Disruptor Screening Program 

Nicarbazin was not included in the first group of 67 chemicals issued an order to conduct Tier 1 

EDSP testing. For additional information the EDSP program, visit http://www.epa.gov/endo/.

9. Preliminary Identification of Data Gaps

Several previous risk assessments have identified data gaps (DP312669, 313794, 2005; and 

DP328803, 2007). Adequate studies or data have not been submitted since these assessments to fill 
25

the identified data gaps. Data gaps presented in this problem formulation are derived from these 

previous assessments, and are reiterated below. 

a. Environmental Fate 

Table 13 identifies environmental fate studies by OCSPP guideline, classification of MRID and if 

additional data are needed in order to support subsequent risk assessments. Five (5) OCSPP 

guideline studies were submitted by the registrant for nicarbazin. Only one study, hydrolysis 

(MRID 464453305), is classified as acceptable, and two terrestrial field dissipation studies are 

supplemental, but not upgradeable (MRID 46416449, and 46445306). Two studies are classified 

unacceptable and include aerobic soil metabolism (MRID 46416446), and adsorption/ desorption, 

leaching (MRID 46416447). 

Eight OCSPP guideline study types have not been submitted. EFED has determined the following 

studies are not needed because of the use pattern described on the currently registered OvoControl P 

labels: 

x Aquatic field dissipation study (835.6200); and, 

x Anaerobic soil metabolism (835.4200). 

Based on the pathways of concern and proposed analysis plan, EFED recommends the following 

OCSPP guideline studies and corresponding data, to complete the Registration Review program’s

exposure assessments: 

x Batch Equilibrium (835.1230; 835.1240) for the nicarbazin complex and the constituents 

(DNC and HDP); 

x Hydrolysis (835.2120) on the nicarbazin complex; 

x Aqueous Photolysis (835.2240) for the nicarbazin complex and the two constituents (DNC 

and HDP); 

x Aerobic Soil Metabolism (835.4100) for the nicarbazin complex and the two constituents 

(DNC and HDP); and, 

x Aerobic aquatic metabolism (835.4300) for the nicarbazin complex and the two constituents 

(DNC and HDP); 

x Anaerobic aquatic metabolism (835.4400) for the nicarbazin complex and the two 

constituents (DNC and HDP); 

x Analytical methods in soil (850.6100) for the nicarbazin complex and the two constituents 

(DNC and HDP); 

x Analytical methods in water (850.6100) for the nicarbazin complex and the two constituents 

(DNC and HDP); and 

x Fish bioconcentration factor (850.1730) for the nicarbazin complex and the two constituents 

(DNC and HDP). 

More information on the physical properties of the Nicarbazin complex (octanol-water partition 

coefficient, Kow), and results of the Hydrolysis study (835.2120) are needed to decide on the 

waiver of the Fish bioccumulation study (850.1730). 

The environmental fate assessment will consider both components of nicarbazin (DNC and HDP). 

Therefore, sufficient data will be needed for both components. HDP was noted to enhance 
26

adsorption of DNC; therefore, risk of DNC may be considerably different in the presence of HDP. 

For this reason, quantifying the duration of potential co-occurrence of HDP and DNC in water is 

important to risk assessment. 

Table 12: Status of Environmental Fate and Transport Data. 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID)

Study

Classification 

Sufficient for 

risk 

assessment? 

Comments 

835.1230

835.1240 

Adsorption/ 

desorption,

leaching 

46416447 Unacceptable No

Study used obsolete methods 

and was insufficiently 

documented. 

835.1410 Volatility –

laboratory None N/A No Data not needed for current use pattern 

835.2120 Hydrolysis 464453305 Acceptable No Study did not include nicarbazin 

complex. 

835.2240 Aqueous 

photolysis

46416445

(waiver 

request) 

N/A No Waiver request denied 

(DP312669, 2005). 

835.2410 Soil photolysis None N/A No Data not needed for current use 

pattern. 

835.4100 Aerobic soil 

metabolism 46416446 Unacceptable No

Aerobic soil metabolism was 

studied as part of an outdoor 

field study (46416449), and not 

a laboratory study. 

835.4200 Anaerobic soil 

metabolism None N/A N/A Data not needed for current use pattern. 

835.4300 Aerobic aquatic 

metabolism None N/A No Data needed for registration review risk assessment. 

835.4400 Anaerobic aquatic 

metabolism None N/A No Data not needed for current use pattern. 

835.6100 Terrestrial field 

dissipation 46416449 Supplemental, not upgradeable No

Reviewed as non-guideline. 

Although individual 

contributions of the 

degradation pathways were not 

determined, half-lives were 

estimated (301d) 

835.6100 Terrestrial field 

dissipation 46445306 Supplemental, not upgradeable No Reviewed as non-guideline

835.6200 Aquatic field 

dissipation None N/A N/A Data not needed for current use pattern. 

850.1730 Fish

bioconcentration 

46497102

(waiver 

request) 

N/A No Waiver request denied 

(DP312669, 2005) 

850.6100 Analytical 

method in soil None N/A No Data needed for registration review risk assessment. 

850.6100 Analytical 

method in water None N/A No Data needed for registration review risk assessment. 

Abbreviations: d = days; N/A = not applicable 
27

More information on the physical properties of the Nicarbazin complex (octanol-water partition 

coefficient, Kow) and results of the Hydrolysis study (161-1) are needed to decide on the waiver of 

the Fish Accumulation study (165-4). 

b. Effects 

Table 14 through Table 15 identify ecological effects studies for nicarbazin by MRID 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 non-guideline data 

requested is presented below the tables.

Table 13: Submitted Aquatic Ecological Effects Data for Nicarbazin 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID)

Study

Classifications 

Sufficient for 

risk 

assessment? 

Comments; 

Current Additional Data Need 

850.1010 

Freshwater 

invertebrate 

acute toxicity 

46416435 Acceptable 

No 

For the aquatic toxicity testing, data is 

available on the DNC and HDP 

components individually, not the 

nicarbazin complex (HDP + DNC).

Therefore, additional data are needed 

for acute toxicity evaluating the 

nicarbazin complex to aquatic 

organisms. Freshwater data can be 

used for saltwater organism data. 

46416436 Acceptable 

850.1025

or

850.1035

Saltwater 

invertebrate 

acute toxicity 

(None) (Not applicable) No 

No acute saltwater invertebrate data 

are available; there is the potential for 

exposure to estuarine/marine 

environment. However, given the low 

toxicity of the individual 

components, freshwater data can be 

used in lieu of the saltwater data. 

850.1075 Freshwater fish 

acute toxicity 

46416431 Acceptable 

No 

For the aquatic toxicity testing, data is 

available on the DNC and HDP 

components individually, not the 

nicarbazin complex. Therefore, 

additional data are needed for acute 

toxicity evaluating the nicarbazin 

complex to aquatic organisms. 

Freshwater data can be used for 

saltwater organism data.

46416432 Acceptable 

46416433 Supplemental 

46416434 Supplemental 

850.1075 Saltwater fish 

acute toxicity (None) (Not applicable) No

No acute saltwater fish data are 

available; there is the potential for 

exposure to estuarine/marine 

environment. However, given the 

low toxicity of the individual 

components, freshwater data can be 

used in lieu of the saltwater data. 
28

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID)

Study

Classifications 

Sufficient for 

risk 

assessment? 

Comments; 

Current Additional Data Need 

850.1300 

Freshwater 

invertebrate 

life-cycle 

(None) (Not applicable) No 

No chronic aquatic organism toxicity 

data are available for nicarbazin. 

Therefore, a freshwater invertebrate 

life-cycle study is needed for DNC 

alone as well as the nicarbazin 

complex. 

850.1350 

Saltwater 

invertebrates 

life-cycle 

(None) (Not applicable) N/A 

No chronic aquatic organism toxicity 

data are available for nicarbazin. 

However, freshwater data can be 

used in lieu of the saltwater data. 

850.1400 Freshwater fish 

early-life stage (None) (Not applicable) See below (850.1500) 

No chronic aquatic organism toxicity 

data are available for nicarbazin. 

However, given the need for a 

reproduction study, a fish full lifecycle study (OCSPP 850.1500) is

being recommended instead. 

850.1400 Saltwater fish 

early-life stage (None) (Not applicable) N/A 

No chronic aquatic organism toxicity 

data are available for nicarbazin. 

However, given the need for a 

reproduction study, a fish full lifecycle study is being recommended

instead. Freshwater data can be used 

in lieu of the saltwater data. 

850.1500 Fish life-cycle (None) (Not applicable) No 

No chronic aquatic organism 

toxicity data are available for 

nicarbazin. Therefore, a freshwater 

full life-cycle study is needed for 

DNC alone as well as the nicarbazin. 

NonGuideline 

Sediment 

Toxicity -

Chronic

(None) (Not applicable) No

No sediment toxicity data are 

available for nicarbazin. Based on 

the available chemical information, 

chronic sediment toxicity data are 

needed for DNC alone as well as the 

nicarbazin complex. 

850.4400 

Aquatic plant 

Toxicity Test 

using Lemna

spp. 

(None) (Not applicable) 

No 

No aquatic plant toxicity data are 

available for nicarbazin. Therefore, 

data are needed for DNC alone as

well as the nicarbazin complex, to

evaluate toxicity to aquatic plants. 

The preferred vascular aquatic plant 

toxicity test species is Lemna spp.,

and the preferred non-vascular 

aquatic plant species are 3 algal 

species plus cyanobacteria. 

850.4500 Algal toxicity (None) (Not applicable) 

850.4550 Cyanobacteria (None) (Not applicable) 
29

Table 15. Submitted Terrestrial Ecological Effects Data for Nicarbazin

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID)

Study

Classifications 

Sufficient for 

risk 

assessment? 

Comments; 

Current Additional Data Need 

850.2100 Avian oral 

toxicity 46416426 Acceptable No

A study in a passerine species, with 

the nicarbazin complex (HDP + 

DNC) as the test material, is needed 

to fulfill guideline requirements.

The Tier 1 EEC from past avian 

assessments was 5000 ppm, the 

acute LD50 > 2250 mg/kg-bw, and

the sub-acute LC50 = 3680 mg/kgdiet for the game bird species tested. 

The passerine LD50 would have to 

be at least 23 times greater than for 

the other avian species tested to not 

result in an acute listed species LOC 

exceedance of 0.1. 

850.2200 Avian dietary 

toxicity 

46416427 Acceptable Yes None.

46445302 Acceptable 

850.2300 Avian 

reproduction (None) (Not applicable) No

No guideline avian reproduction 

study has yet to be submitted to the 

Agency. It was identified as a data 

gap beginning in the 2005 

Assessment (USEPA 2005).

Numerous non-guideline studies 

have been submitted and reviewed 

over the years (DP363859, 

DP363860, USEPA 2009; 

DP372345, DP372348, DP349126,

USEPA 2010; DP396672, USEPA 

2011; DP400098, USEPA 2012; 

DP415695, USEPA 2014). However,

the registrant has agreed to, and is 

currently working on, an adapted 

avian reproduction study that will 

provide the needed data (protocol 

review: DP424098, USEPA 2015b). 

810.4250 Avian 

toxicants 47556001 Supplement Info. N/A Field efficacy study in pigeons; no additional data needed. 

850.2500

(form. 71-5) 

Field Testing 

for Terrestrial 

Wildlife

46497103 Supplemental N/A

OvoControl G ready use bait field 

study; test efficacy of field 

applications of Goose product.

Non-target species (including 

passerine species, humans, small 

mammals, etc.) were observed at 

bait stations. No data needed for 

current use pattern. 
30

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID)

Study

Classifications 

Sufficient for 

risk 

assessment? 

Comments; 

Current Additional Data Need 

870.1100 Mammalian 

acute oral 46416413 Acceptable Yes None; unless HED informs us otherwise. 

870.1300 

Mammalian 

acute 

inhalation 

None (Not applicable) No None; unless HED informs us 

otherwise.

870.3700 Mammalian - 

developmental 46416421 Acceptable Yes None; unless HED informs us otherwise. 

870.3800 

Mammalian 

2-generation 

Reproduction 

46416422 Acceptable Yes None; unless HED informs us 

otherwise.

850.3020 

Honey bee 

adult acute 

contact 

toxicity 

(None) (Not applicable) Yes

No potential for exposure;

therefore pollinator data are not

needed at this time (USEPA, 2014b). 

850.4100 Seedling 

Emergence (None) (Not applicable) Yes No potential for exposure, data are 

not needed at this time.

850.4150 Vegetative 

Vigor 

Data Gaps 

Aquatic tests are needed for DNC alone & nicarbazin complex (HDP + DNC) for the following, 

except the acute freshwater fish and invertebrate studies, in which tests are needed only for the 

nicarbazin complex. 

x OCSPP 850.1010: Freshwater invertebrate acute toxicity (nicarbazin complex only)

x OCSPP 850.1075: Freshwater fish acute toxicity (nicarbazin complex only)

x OCSPP 850.1300: Freshwater invertebrate life-cycle

x OCSPP 850.1500: Freshwater fish full life-cycle 

x Non-Guideline: Chronic sediment toxicity (3 species; midge, and freshwater and 

estuarine amphipods) 

x OCSPP 850.4400: Aquatic vascular plant toxicity (duckweed) 

x OCSPP 850.4500 and 850.4550: Aquatic non-vascular plant toxicity (3 algal species + 

cyanobacteria)

Terrestrial tests are needed for the nicarbazin complex (HDP + DNC).

x OCSPP 850.2100: Avian acute oral toxicity with passerine species (nicarbazin complex 

(HDP + DNC; as Current Product; OvoControl P) 

x OCSPP 850.2300: Avian reproduction – modified study currently in progress as 

 discussed with registrant (protocol review; DP424098, USEPA 2015b)
31

10. References 

Boxall, A.B.A, et al. 2003a. Are veterinary medicines causing environmental risks? Environ. Sci. 

 Technol. 37: 286A-294A. 

Boxall, ABA, et al. 2003b. Prioritisation of veterinary medicines in the UK environment. 

Toxicology Letters. 142: 207-218. 

Chapman, H.D. 1994. A review of the biological activity of the anticoccidial drug nicarbazin and 

 its application for the control of coccidiosis in poultry. Poultry Sci. Res. 5:231-243. 

EFSA. 2003. Opinion of the Scientific Panel on Additives and Products or Substances Used in 

 Animal Food on the Request From the Commission on the Efficacy and Safety of the 

 Coccidiostat Koffogran. European Food Safety Authority, Scientific Panel on Additives and

 Products or Substances Used in Animal Feed (FEEDAP Panel), The EFSA Journal 16: 1-40. 

Mathies, T. and L.A. Miller. 2005. Nicarbazin as a potential fertility control agent in the African 

 house snake, a model species for the brown tree snake. Lab ID No. QA-72 1. National 

 Wildlife Research Center, Fort Collins, CO. 16 p. 

Primus, T.M., Kohler, D.J., Goodall, M.A., Yoder, C., Mathies, T., Miller, L, Johnston, J.J., and 

Vercauteren, K. 2003. Liquid Chromatographic Determination of 4,4’-Dinitrocarbanilide, 

the Active Component of the Infertility Agent Nicarbazin, in Chicken, Duck, Goose, and 

Snake Eggs. Journal of AOAC International. 86(6):1144-1148. 

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. 2005a. Environmental Risk Assessment for the Proposed Registration of Nicarbazin to 

 Reduce Egg Hatching in Resident Canada Geese. Dated October 13, 2005. PC Code: 

 085712; DP Barcodes: 312669, 313794. 

USEPA. 2005b. Amendment to the October 13, 2005 Environmental Risk Assessment for the 

 Proposed Registration of Nicarbazin to Reduce Egg Hatching in Resident Canada Geese 

 (DP Barcodes: 312669, 313794). Dated November 18, 2005. PC Code: 085712; DP 

 Barcodes: 312669, 313794. 

USEPA. 2007a. Environmental Risk Assessment for the Proposed Registration of Nicarbazin 

 (OvoControl P) to Reduce Egg Hatching in Pigeons. Dated April 12, 2007. PC Code: 

 085712; DP Barcode: 328803. 

USEPA. 2007b. Ecological Risk Assessment for the Section 3 New Use Registration of Nicarbazin 

 on Non-Native Hybrid, Domestic and Muscovy Ducks. Dated November 8, 2007. PC 

 Code: 085712; DP Barcodes: 340973, 335890. 
32

USEPA. 2007c. Section 24(c) Special Local Need Registration of Nicarbazin (OvoControl P) for 

 use on Pigeons (Columbia livia) in Hawaii. Dated November 8, 2007. PC Code: 085712; 

 DP Barcodes: 344692. 

USEPA. 2007d. 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/ 

USEPA. 2009. EFED Review of Request from Innolytics, LLC to Remove Restricted Use 

Classification for Goose and Pigeon Contraceptive Products. Dated November 20, 2009. PC 

Code 085712, DP Barcodes: 363859 and 363860. 

USEPA. 2010. EFED Review of Rebuttal from Innolytics, LLC Regarding EFED’s Response from 

Innolytics, LCC to Remove Restricted Use Classification for Goose and Pigeon 

Contraceptive Products. Dated January 21, 2010. PC Code 085712, DP Barcodes: 372345, 

372348, and 349126.

USEPA. 2011. EFED Review of Innolytics, LLC Request for Waiving Avian Reproduction. Data 

Requirement for Nicarbazin. Dated December 23, 2011. PC Code: 085712; DP Barcode: 

396672.

USEPA. 2012. EFED Review of Innolytics, LLC Request for Waiving Avian Reproduction Data 

Requirement for Nicarbazin. Dated May 31, 2012. PC Code: 085712; DP Barcode: 

400908.

USEPA. 2014a. EFED Review of Innolytics, LLC Request for Waiving Avian Reproduction 

 Data Requirement for Nicarbazin. Dated February 10, 2014. PC Code: 085712; DP 

 Barcode: 415695. 

USEPA. 2014b. 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.

USEPA. 2015a. Memorandum “BEAD Chemical Profile for Registration Review: Nicarbazin 

 (PC Code 85712).” From C. Cook, Through A. Jones, BEAD; To B. Adler, PRD. Dated 

 February 23, 2015. Office of Chemical Safety and Pollution Prevention, U.S. Environmental 

 Protection Agency, Washington, D.C. 

USEPA. 2015b. Nicarbazin: Review of Study Protocol to fulfill Avian Reproduction Study. Dated 

 March 4, 2015. PC Code: 085712; DP Barcode: 424098. 

WHO. 1998. Nicarbazin - Toxicological Evaluation of Certain Veterinary Drug Residues In Food. 

 WHO Food Additive Series 41, World Health Organization International Programme On 

 Chemical Safety, Geneva. 9 p. 

http://www.inchem.org/documents/jecfa/jecmono/v041je10.htm
33

a. Submitted Environmental Fate Studies 

MRID Citation Reference 

46416400 Innolytics, LLC (2004) Submission of Product Chemistry, Toxicity, Fate, Efficacy and 

Environmental Fate Data in Support of the Application for Registrations of OvoControl-P, 

Nicarbazin 30% Granulated Premix, and OvoControl-G. Transmittal of 43 Studies. 

46416401 Wolf, E.; MacDonald, A. (2004) Product Identity and Composition, Certification of Ingredient 

Limits, and Discussion of Impurities of Nicarbazin and Nicarbazin 30% Granulated Premix. 

Project Number: NICARBAZIN/04/22. Unpublished study prepared by Exponent. 51 p. 

46416402 Wolf, E.; MacDonald, A. (2004) Product Identity and Composition, Certification of Ingredient 

Limits, and Discussion of Impurities of OvoControl-G and OvoControl-P. Project Number: 

NICARBAZIN/04/34. Unpublished study prepared by Exponent. 16 p. 

46416403 Wolf, E.; MacDonald, A. (2004) Description of Materials Used to Produce the Product, 

Description of Production Process, Description of Formulation Process, Preliminary Analysis 

for Nicarbazin and the Manufacturing Use Product Nicarbazin 30% Granulated Premix. Project 

Number: NICARBAZIN/04/08/03. Unpublished study prepared by Exponent. 130 p. 

46416404 Wolf, E.; MacDonald, A. (2004) Description of Materials Used to Produce the Product, 

Description of Production Process, Description of Formulation Process, and Prelimonary 

Analysis for OvoControl-G and OvoControl-P. Project Number: NICARBAZIN/04/37. 

Unpublished study prepared by Exponent. 77 p. 

46416406 Wolf, E.; MacDonald, A. (2004) Description and Validation of Analytical Method for the 

Determination of Nicarbazin in Goose Baits by HPLC/UV. Project Number: 

NICARBAZIN/04/36, P0000814, P0000545. Unpublished study prepared by Exponent. 38 p. 

46416407 Wolf, E.; MacDonald, A. (2004) Description of Color, Physical State, Odor, Melting Point, 

Specific Gravity, Solubility, Vapor Pressure, Dissociation Constant, pH, Stability, and Particle 

Size for Nicarbazin. Project Number: NICARBAZIN/04/31. Unpublished study prepared by 

Exponent. 31 p. 

46416408 Wolf, E.; MacDonald, A. (2004) Description of Color, Physical State, Odor, Bulk Density, pH, 

Flammability, Explodability, Particle Size and Shape, Storage Stability, and Corrosion 

Characteristics for Nicarbazin 30% Granulated Premix. Project Number: NICARBAZIN/04/32. 

Unpublished study prepared by Exponent. 8 p. 

46416409 Wolf, E.; MacDonald, A. (2004) Description of Color, Physical State, Odor, Bulk Density, pH, 

Flammability, Explodability, Particle Size and Shape, Storage Stability, and Corrosion 

Characteristics for OvoControl-G and OvoControl-P. Project Number: NICARBAZIN/04/33. 

Unpublished study prepared by Exponent. 6 p. 

46416410 Wolf, E. (2004) The Determination of the Distribution Coefficients of the Components of 

Nicarbazin Between 1-Octanol and Aqueous Buffers (ADM-56). Project Number: 

NICARBAZIN/04/08/05. Unpublished study prepared by Exponent. 17 p. 

46416411 McCracken, B. (2004) Water Solubility of DNC and HDP. Project Number: P0000936. 

Unpublished study prepared by Exygen Research. 26 p. 

46416412 Habig, C.; Messina, J.; Daniels, C. (2004) Nicarbazin Support Documentation. Project Number: 

NICARBAZIN/04/30. Unpublished study prepared by Exponent. 112 p. 
34

MRID Citation Reference 

46416445 Habig, C.; Messina, J.; Daniels, C. (2004) Nicarbazin Waiver Request from Further Testing: 

Aqueous Photolysis. Project Number: NICARBAZIN/04/25. Unpublished study prepared by 

Exponent. 10 p. 

46416446 Wolf, E. (2004) A Study to Determine the Rate of Depletion of Ionophore and 14-C Nicarbazin 

in a Field Soil Plot. Project Number: NICARBAZIN/04/13. Unpublished study prepared by 

Exponent. 7 p. 

46416447 Wolf, E. (2004) Mobility of 14-C DNC on Soil Thin-Layer Plates. Project Number: 

NICARBAZIN/04/15. Unpublished study prepared by Exponent. 8 p. 

46416449 Manthey, J. (1985) A Study to Determine the Rate of Depletion of Narasin and 14-C 

Nicarbazin in a Field Soil Plot. Project Number: ABC/0284. Unpublished study prepared by 

Exponent. 55 p. 

46445300 Innolytics, LLC (2005) Submission of Product Chemistry, Toxicity, Environmental Fate Data 

in Support of the Application for Registrations of LLC/Nicarbazin 30% Granulated Premix, 

Ovocontrol P and Ovocontrol G. Transmittal of 6 Studies. 

46445301 Wolf, E.; MacDonald, A. (2004) Description of Analytical Methods for Nicarbazin and the 

Manufacturing Use Product Nicarbazin 30% Granulated Premix, Impurities, and Quality 

Control Processes. Project Number: NICARBAZIN/04/24. Unpublished study prepared by 

Exponent. 82 p. 

46445305 McCracken, B. (2004) Aqueous Hydrolysis of Nicarbazin Under Laboratory Conditions 

Amendment 1. Project Number: EXP/108/002, P0000693. Unpublished study prepared by 

Exygen Research. 55 p. 

46445306 Manthey, J. (1984) A Greenhouse Study to Determine the Rate of Decline of Soil Incorporated 

Narasin and 14C Nicarbazin Singly and in Combination. Project Number: ABC/0209. 

Unpublished study prepared by Exponent. 58 p. 

46459800 Innolytics, LLC (2005) Submission of Toxicity and Fate Data in Support of the Application for 

Registration of Nicarbazin. Transmittal of 2 Studies. 

46459801 Habig, C.; Messina, J.; Daniels, C. (2005) Nicarbazin Waiver Request from Further Testing. 

Project Number: NICARBAZIN/04/40. Unpublished study prepared by Exponent. 10 p. 

46459802 Habig, C.; Messina, J.; Daniels, C. (2005) Nicarbazin Waiver Request from Further Testing. 

Project Number: NICARBAZIN/04/39. Unpublished study prepared by Exponent. 11 p. 

46471700 Innolytics, Inc. (2005) Submission of Environmental Fate Data in Support of the Application 

for Registration of Nicarbazin. Transmittal of 1 Study. 

46497100 Innolytics. LLC. (2005) Submission of Toxicity and Efficacy Data in Support of the 

Application for Registration of Ovocontrol P. Transmittal of 3 Studies. 

46497102 Habig, C.; Messina, J.; Daniels, C. (2005) Nicarbazin Waiver Request from Further Testing: 

Fish Accumulation. Project Number: NICARBAZIN/03/15. Unpublished study prepared by 

Exponent. 9 p. 

46998500 Innolytics, LLC (2006) Submission of Efficacy Data in Support of the Application for 

Registration of OvoControl P. Transmittal of 1 Study. 

46998501 Wolf, E. (2006) Italian Ministry of Health: Registration of Ovistop Brand of Nicarbazin. 

Project Number: NICARBAZIN. Unpublished study prepared by Innolytics, LLC. 5 p. 
35

MRID Citation Reference 

47520300 Innolytics, LLC. (2008) Submission of Product Chemistry Data in Support of the Registration 

of OvoControl P 0.5%. Transmittal of 1 Study. 

47520301 MacDonald, A. (2008) Corrosion Characteristics and Stability of OvoControl P 0.5% 

(Nicarbazin). Unpublished study prepared by Innolytics, LLC. 7 p. 

b. Submitted Ecological Toxicity Studies 

MRID Citation Reference 

46416426 Gallagher, S.; Beavers, J. (2004) Nicarbazin Technical: An Acute Oral Toxicity Study With 

the Northern Bobwhite. Project Number: 573/103. Unpublished study prepared by Wildlife 

International, Ltd. 30 p. 

46416427 Gallagher, S.; Beavers, J. (2004) Nicarbazin Technical: A Dietary LC50 Study with the 

Northern Bobwhite. Project Number: 573/101, P0000736. Unpublished study prepared by 

Wildlife International, Ltd. 89 p. 

46445302 Gallagher, S.; Beavers, J. (2004) Nicarbazin Technical: A Dietary LC50 Study with the 

Mallard. Project Number: 573/102, Unpublished study prepared by Wildlife International, Ltd. 

47556000 Innolytics, LLC (2008) Submission of Efficacy Data in Support of the Registration of 

OvoControl P 0.5 percent for Pigeons. Transmittal of 1 Study. 

47556001 MacDonald, A. (2008) OvoControl P 0.5 percent (Nicarbazin) Field Efficacy Study in Pigeons. 

Project Number: NICARBAZIN, 95C, 08/034. Unpublished study prepared by Innolytics, 

LLC. 199p. 

46416429 Habig, C.; Messina, J.; Daniels, C. (2004) Nicarbazin Waiver Request From Further Testing: 

Wild Mammal Toxicity. Project Number: NICARBAZIN/04/28. Unpublished study prepared 

by Exponent. 8p. 

46445303 Messina, J. (2004) Nicarbazin Avian Reproduction. Project Number: NICARBAZIN/04/18. 

Unpublished study prepared by Wildlife International, Ltd. 35 p. 

46497101 Wolf, E. (2005) Nicarbazin Avian Reproduction Support Documentation. Project Number: 

QA/737, QA/774, QA/850. Unpublished study prepared by US Dept. of Agriculture, APHIS, 

WS, University of Georgia and Clemson University. 115 p. 

46416431 Palmer, S.; Krueger, H. (2004) 2-Hydroxy-4,6 Dimethypyrimidine (HDP): A 96-Hour Static 

Acute Toxicity Test With The Rainbow Trout (Oncorhynchus mykiss): Final Report. Project 

Number: 573A/109, P997, V0002054/3. Unpublished study prepared by Exponent. 90 p. 

46416432 Palmer, S.; Krueger, H. (2004) 4,4'-Dinitrocarbanilide (DNC): A 96-Hour Static Acute 

Toxicity Test with the Rainbow Trout (Oncorhynchus mykiss): Final Report. Project Number: 

573A/106. Unpublished study prepared by Wildlife International, Ltd. 89 p. 

46416433 Palmer, S.; Krueger, H. (2004) 2-Hydroxy-4,6 Dimethylpyrimidine (HDP): A 96-Hour Static 

Acute Toxicity Test with the Bluegill (Lepomis macrochirus): Final Report. Project Number: 

573A/108. Unpublished study prepared by Wildlife International, Ltd. 89 p. 

46416434 Palmer, S.; Krueger, H. (2004) 4,4'-DinitroCarbanilide (DNC): A 96-Hour Static Acute 

Toxicity Test with the Bluegill (Lepomis macrochirus): Final Report. Project Number: 

573A/105. Unpublished study prepared by Wildlife International, Ltd. 90 p. 
36

MRID Citation Reference 

46416437 Wolf, E. (2004) Nicarbazin Acute Freshwater Fish, Aquatic Invertebrates, Alga Toxicity. 

Project Number: NICARBAZIN/04/19. Unpublished study prepared by Exponent. 16 p. 

46416435 Palmer, S.; Krueger, H. (2004) 2-Hydroxy-4,6 Dimethylpyrimidine (HDP): A 48-Hour Static 

Acute Toxicity Test with the Cladoceran (Daphnia magna): Final Report. Project Number: 

573A/107C. Unpublished study prepared by Wildlife International, Ltd. 90 p. 

46416436 Palmer, S.; Krueger, H. (2004) 4,4'-Dinitrocarbanilide (DNC): A 48-Hour Static Acute 

Toxicity Test with the Cladoceran (Daphnia magna): Final Report. Project Number: 

573A/104A. Unpublished study prepared by Wildlife International, Ltd. 91 p. 

46416438 Habig, C.; Messina, J.; Daniels, C. (2004) Nicarbazin Waiver Request from Further Testing: 

Acute LC50 Estuarine and Marine Organisms, Fish Early Life Stage and Aquatic Invertebrate 

Life-Cycle, Fish Life-Cycle, Aquatic Organism Accumulation, and Simulated or Actual Field 

Testing-Aquatic Organisms. Project Number: NICARBAZIN/04/21. Unpublished study 

prepared by Exponent. 9 p. 

46416413 Messina, J. (2004) Nicarbazin Acute Oral Toxicity LD50: (Rat). Project Number: 

NICARBAZIN/04/12. Unpublished study prepared by Exponent. 7 p. 

46416414 Messina, J.; Daniels, C. (2004) Nicarbazin Waiver Request from Further Testing: Acute 

Dermal Toxicity LD50. Project Number: NICARBAZIN/04/29. Unpublished study prepared 

by Exponent. 8 p. 

46416415 Brooker, A. (2001) Koffogran: Acute (Four-Hour) Inhalation Study in Rats. Project Number: 

CYT/044/014207,NICARBAZIN/04/02. Unpublished study prepared by Huntingdon Life 

Sciences, Ltd. 35 p. 

46416416 Blanchard, E. (2001) Koffogran: Eye Irritation to the Rabbit. Project Number: 

NICARBAZIN/04/02, CYT/002/013543/SE. Unpublished study prepared by Huntingdon Life 

Sciences, Ltd. 16 p. 

46416417 Blanchard, E. (2001) Koffogran: Skin Irritation to the Rabbit. Project Number: 

NICARBAZIN/04/03, CYT/001/013542/SE. Unpublished study prepared by Huntingdon Life 

Sciences, Ltd. 15 p. 

46416418 Coleman, D. (2001) Koffogran: Skin Sensitization to the Guinea-Pig (Buehler Method - 9 

Inductions). Project Number: NICARBAZIN/04/04, CYT/003/013699/SS. Unpublished study 

prepared by Huntingdon Life Sciences, Ltd. 28 p. 

46645600 Innolytics, LLC (2005) Submission of Toxicity Data in Support of the Application for 

Registration of OvoControl G. Transmittal of 1 Study. 

46645601 Messina, J.; Daniels, C. (2005) Nicarbazin Waiver Request from Further Testing: Acute 

Inhalation Toxicity LC50. Project Number: NICARBAZIN/05/01. Unpublished study prepared 

by Exponent. 8 p. 

46416419 Messina, J. (2004) Nicarbazin Chronic Toxicity Rat. Project Number: NICARBAZIN/04/08. 

Unpublished study prepared by Exponent. 184 p. 

46416420 Messina, J. (2004) Nicarbazin Chronic Toxicity Dog. Project Number: NICARBAZIN/04/07. 

Unpublished study prepared by Exponent. 184 p. 

46416421 Messina, J. (2004) Nicarbazin Developmental Toxicity. Project Number: 

NICARBAZIN/04/10. Unpublished study prepared by Exponent. 50 p. 
37

MRID Citation Reference 

46416422 Messina, J. (2004) Nicarbazin Multigeneration Reproduction Toxicology. Project Number: 

NICARBAZIN/04/05. Unpublished study prepared by Exponent. 48 p. 

46416423 Messina, J. (2004) Nicarbazin Genotoxicity. Project Number: NICARBAZIN/04/09. 

Unpublished study prepared by Exponent. 20 p. 

46416424 Innes, D. (2001) Nicarbazin: Micronucleus Test in Bone Marrow of CD-1 Mice 0 h + 24 h 

Oral Dosing and 48 h Sampling. Project Number: 20677, NICARBAZIN/04/11, 767115. 

Unpublished study prepared by Inveresk Research International. 31 p. 

46416425 Messina, J. (2004) Nicarbazin Metabolism. Project Number: NICARBAZIN/04/06. 

Unpublished study prepared by Exponent. 252 p. 

46416439 Habig, C.; Messina, J.; Daniels, C. (2004) Nicarbazin Waiver Request from Further Testing: 

Seedling Emergence, Vegetative Vigor and Aquatic Plant Growth. Project Number:

NICARBAZIN/04/20. Unpublished study prepared by Exponent. 8 p. 

46471701 Wolf, E. (2005) Determination of the Toxicity of Nicarbazin (Nicarbazin) and Supacox 

(Pancoxin Plus) to Eight Higher-Plant Species by Soil Application. Project Number: 

NICARBAZIN/04/38, WD00775/000. Unpublished study prepared by Exponent. 47 p. 

46416440 Habig, C.; Messina, J.; Daniels, C. (2004) Nicarbazin Waiver Request from Further Testing: 

Honey Bee Acute Contact LD50, Honey Bee Toxicity of Residues on Foliage, and Field 

Testing for Pollinators. Project Number: NICARBAZIN/04/20. Unpublished study prepared by 

Exponent. 8 p. 

46416441 Messina, J. (2004) Nicarbazin, HDP, and DNC Acute Earthworm Toxicity. Project Number: 

NICARBAZIN/04/16. Unpublished study prepared by Exponent. 58 p. 

46416442 Messina, J. (2004) Nicarbazin Pigeon Efficacy Information. Project Number: NICARBAZIN/ 

04/17. Unpublished study prepared by Exponent. 15 p. 

46445304 Bynum, K.; Eisemann, J.; Miller, L.; et. al. (2004) Efficacy of 2500 ppm Nicarbazin for 

Reproductive Inhibition in Canada Geese. Unpublished study prepared by US Dept. of 

Agriculture, APHIS, WS. 37p. 

46497103 Bynum, K.; Eisemann, J.; Weaver, G.; et al. (2005) QA-1102: Multi-center Field Study of 

Nicarbazin Bait for use in the Reduction in Hatching of Eggs Laid by Local Canada Goose 

(Branta canadensis) Flocks. Project Number: QA/1102. Unpublished study prepared by US 

Dept. of Agriculture, APHIS, WS and Innolytics, LLC. 130 p. 

46820700 Innolytics, LLC (2006) Submission of Toxicity Data in Support of the Application for 

Registration of OvoControl P. Transmittal of 1 Study. 

46820701 Avery, M. (2006) Effects of Nicarbazin Bait on Pigeon Reproduction: OvoControl P. Project 

Number: QA/1239, WD00775/000. Unpublished study prepared by U.S. Dept. of Agriculture, 

A.P.H.I.S. 52 p. 

46851500 Innolytics, LLC (2006) Submission of Toxicity Data in Support of the Application for 

Registration of OvoControl G. Transmittal of 1 Study. 

46851501 MacDonald, A. (2006) Nicarbazin Support Documentation Feral Pigeons - Social and Feeding 

Behavior. Project Number: NICARBAZIN. Unpublished study prepared by Innolytics, LLC 

and Ministry of Agriculture, Fisheries and Food. 76 p. 
38

MRID Citation Reference 

46992100 Innolytics, LLC (2006) Submission of Environmental Fate Data in Support of the Application 

for Registration of OvoControl P. Transmittal of 2 Studies. 

46992101 Avery, M.; Keacher, K.; Tillman, E. (2006) Development of Nicarbazin Bait for Managing 

Rock Pigeon (Columbia livia) Populations. Unpublished study prepared by U.S. Dept. of 

Agriculture, National Wildlife Research Center 29 p. 

46992102 Wolf, E.; MacDonald, A. (2006) Supporting Documentation for the Use of Nicarbazin in Feral 

Pigeons. Unpublished study prepared by Innolytics, LLC. 43 p. 

47043200 Innolytics, LLC (2007) Submission of Fate Data in Support of the Application for Registration 

of OvoControl P. Transmittal of 1 Study. 

47043201 Wolf, E. (2007) Supporting Field Study for the Use of Nicarbazin in Feral Pigeons. Project 

Number: NICARBAZIN. Unpublished study prepared by Innolytics, LLC. 41 p. 

48026600 Innolytics, LLC (2010) Submission of Exposure and Risk Data in Support of the Registration 

of OvoControl P 0.5%. Transmittal of 1 Study. 

48026601 MacDonald, A. (2010) OvoControl P 0.5% (Nicarbazin): Population Dynamics in Pigeons. 

Unpublished study prepared by Innolytics, LLC. 10 p. 

46992400 Innolytics, LLC (2006) Submission of Toxicity and Efficacy Data in Support of the 

Registration of OvoControl G. Transmittal of 1 Study. 

46992401 Barbato, G.; MacDonald, A. (2006) Pekin Duck Model for Action of Nicarbazin on Fertility. 

Project Number: NICARBAZIN. Unpublished study prepared by Innolytics, LLC. 12 p. 

46845800 Innolytics, LLC (2006) Submission of Efficacy Data in Support of the Amended Registration 

of OvoControl G. Transmittal of 1 Study. 

46845801 Bynum, K.; Eisemann, J.; Weaver, G.; et. al. (2006) QA-1102: Multi-Center Field Study of 

Nicarbazin Bait for Use in the Reduction in Hatching of Eggs Laid by Local Canada Goose 

(Branta canadensis) Flocks: Final Report. Project Number: QA/1102, QA/1345. Unpublished 

study prepared by US Dept. of Agriculture, APHIS, WS. 1031 p. 

49474200 Innolytics, LLC (2014) Submission of Toxicity Data in Support of the Registration of 

Nicarbazin. Transmittal of 1 study. 

49474201 Stafford, J. (2014) Nicarbazin: Reproductive NOEAC Test with the Northern Bobwhite 

(Colinus virginianus). Unpublished study prepared by Smithers Viscient. 11p. 
39

APPENDIX A. SIP Inputs and Outputs for Nicarbazin (DNC & HDP components) 

Table 1. Inputs

Parameter Value

Chemical name Nicarbazin (DNC moiety)

Solubility (in water at 25oC; mg/L) 0.076

Mammalian LD50 (mg/kg-bw) 10000

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 200

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 2250

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor

Mallard NOAEC (mg/kg-diet)

Bobwhite quail NOAEC (mg/kg-diet)

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) 0.0131 0.0131

Adjusted toxicity value (mg/kg-bw) 7691.6057 153.8321

Ratio of exposure to toxicity 0.0000 0.0001

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.0616 0.0616

Adjusted toxicity value (mg/kg-bw) 20025.0000 0.0000

Ratio of exposure to acute toxicity 0.0000 0.0000

Conclusion*

Drinking water exposure 

alone is NOT 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.
40

Table 1. Inputs

Parameter Value

Chemical name Nicarbazin_HDP moiety

Solubility (in water at 25oC; mg/L) 10000

Mammalian LD50 (mg/kg-bw) 4000

Mammalian test species other

Body weight (g) of "other" mammalian species 35

Mammalian NOAEL (mg/kg-bw) 200

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 2250

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor

Mallard NOAEC (mg/kg-diet)

Bobwhite quail NOAEC (mg/kg-diet)

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

Enter body weight of 'other' mammalian species for LD50.

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 1720.0000 1720.0000

Adjusted toxicity value (mg/kg-bw) 1730.1231 153.8321

Ratio of exposure to toxicity 0.9941 11.1810

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) 8100.0000 8100.0000

Adjusted toxicity value (mg/kg-bw) 20025.0000 0.0000

Ratio of exposure to acute toxicity 0.4045 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.