Date: 

Subject: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

November I 0, 2015 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

Nicarbazin. Occupational and Residential Exposure and Risk Assessment for 

Registration Review. 

PC Code: 085712 

Decision Number: 505007 

Petition Number: NA 

DP Barcode: 0429981 

Registration Number: 80224-1, 80224-2 

Regulatory Action: Registration Review 

Risk Assessment Type: NA Case Number: 7628 

TXR Number: NA CAS Number: 330-95-0 

MRID Numbers: NA 40CFR: NA 

From: 

T hrough: 

To: 

Matthew 

Risk Assessment 

Crowley

Branch 

, Biologi

2 

st CRf / ~ B2) 

Health Effects Division (HED; 7509P) 

Christina 

Ri

Health 

sk Assessment 

Effects 

Swartz, 

Div

Branch 

Branch 

ision (H

2 

Chief 

ED; 

(RAB2) 

7509P) 

~ 

and 

Seyed Tadayon, Reviewer £~~ Shalu 

Exposure 

Shelat, 

Science 

Revi Advisory ewe ~ 

Committee (ExpoSAC) I HED 

Bonnie Adler, Chemical Review Manager 

Risk Management and Implementation Branch 5 (RM 185) 

Pesticide Re-evaluation Division (PRO) 

As part of Registration Review, the Pesticide Re-evaluation Division (PRD) of EPA's Office of 

Pesticide Programs (OPP) has requested that the Health Effects Division (HED) evaluate the 

hazard and exposure data and conduct occupational and residential exposure assessments, as 

needed, to estimate the risk to human health that will result from the currently registered uses of 

pesticides. This memorandum serves as HED's Registration Revi ew assessment of the 

occupational and residential handler and post-application exposure and risk from the currently 

registered uses of nicarbazin. 

Page I of 14 
It is HED policy to use the best available data to assess exposure. Several sources of generic 

data were used in this assessment as surrogate data in the absence of chemical-specific data, 

including the Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1) and the Outdoor 

Residential Exposure Task Force (ORETF) database. Some of these data are proprietary, and 

subject to the data protection provisions of the Federal Insecticide, Fungicide, and Rodenticide 

Act (FIFRA). 

Note: This memorandum was reviewed by the Exposure Science Advisory Committee 

(ExpoSAC) on 29-0CT-2015. 

Page 2 of 14 
Table of Contents 

1.0 Executive Suminary .............. ....... .... ... ........... .... .............................................. ............. ... .... 4 

2.0 Risk Assessment Conclusions and Recommendations ..................... ............ ....................... 5 

2.1 Summary of Risk Estimates ... ....... .... ........... ..................................... ... ................ ... .......... 5 

2.2 Label Recommendations .............................. ....... .... ... ....... ................................................ 5 

2.3 Data Deficiencies and Requirements .................................... ................ ............................ 5 

3.0 Hazard Characterization ..................................... .... ....... ... .................... ... ............................ 5 

4.0 Exposure and Use Profile .. ........... .... ... .... .... ........... ............................................................. 7 

5.0 Residential Exposure and Risk Estimates .......................................................................... .. 8 

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates ............................................. 8 

7.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates .8 

8.0 Occupational Exposure/Risk Characterization ....... .... ....... .................................................. 9 

8. 1 Occupational Handler Exposure and Risk Estimates ................................................... ..... 9 

Appendix A. Summary of Occupational Non-cancer Algorithms ....... ... ...... ....... ... ... ... .......... ... ... 13 

Page 3of14 
1.0 Executive Summary 

Nicarbazin is the active ingredient in one registered end-use product, OvoControl P (EPA Reg. 

No. 80224-1 ), a 0.5% active ingredient granule/bait pigeon contraceptive packaged in a 30 lb 

bag. Use sites are limited to paved/concrete areas or rooftops of office parks, malls, hospitals, 

schools, bridges, airports, other commercial/industrial buildings/structures. The label specifies 

use in secured areas with limited public access. 

Based on this use pattern, only dermal and inhalation exposures are anticipated for occupational 

handlers (mixer/loaders and applicators). No occupational post-application exposures are 

expected, nor is any non-occupational/residential exposures expected via application, postapplication, spray drift, or volatilization. 

Hazard Profile and Dose Response 

Based on the available data submitted to the agency and an available European Food Safety 

Authority (EFSA) report, the toxicology database for nicarbazin is sufficient for assessing risk. 

Nicarbazin has low acute toxicity, is a moderate eye irritant, and is not a dermal irritant or 

sensitizer. Available studies did not indicate any concerns for neurotoxicity or immunotoxicity. 

No evidence of mutagenicity was observed. 

The lowest observed adverse effect level (LOAEL) of 181 mg/kg/day from the 90-day rat oral 

toxicity study is considered appropriate for assessing risk for all exposure scenarios. A 1 OX 

database uncertainty factor was applied for a LOAEL to no observed adverse effect level 

(NOAEL) extrapolation, resulting in a 1000-fold UF (!OX for interspecies extrapolation, lOX 

for intraspecies variation, and 1 OX Ufdb) for all exposure scenarios. Nicarbazin is a non-food 

use chemical with no residential uses and exposure to children is not expected. Therefore, 

additional safety factors according to the Food Quality Protection Act (FQPA) do not apply. 

Occupational Exposure and Risk 

The quantitative exposure/risk assessment developed for occupational handlers of nicarbazin is 

based on applications of granules by hand or with hand-operated equipment such as a belly 

grinder or rotary spreader. There were no combined (dermal + inhalation) risk estimates of 

concern with label-specified work attire and personal protective equipment (PPE) (long sleeve 

shirt, pants, shoes, socks, gloves). 

The product label specifies wearing a long-sleeved shirt, long pants, shoes, socks, and gloves - it 

does not specify whether the gloves should be chemical-resistant. This should be confirmed, 

both in terms of risk estimates described below assuming the exposure reduction provided by 

chemical-resistant gloves, as well as any other PPE requirements based on the end-use product 

acute toxicity profile. 

Human Studies Review 

Page4of14 
This risk assessment relies in part on data from studies in which adult human subjects were 

intentionally exposed to a pesticide or other chemical. These data, which include studies from 

the Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1) and the Outdoor Residential 

Exposure Task Force (ORETF) database are (1) subj ect to ethics review pursuant to 40 CFR 26, 

(2) have received that review, and (3) are compliant with applicable ethics requirements. For 

certain studies, the ethics review may have included review by the Human Studies Review 

Board. Descriptions of data sources, as well as guidance on their use, can be found at the 

Agency website'. 

2.0 Risk Assessment Conclusions and Recommendations 

2.1 Summary of Risk Estimates 

No occupational dermal or inhalation handl er risks of concern were identified. 

2.2 Label Recommendations 

The product label specifies wearing a long-sleeved shirt, long pants, shoes, socks, and gloves - it 

does not specify whether the gloves should be chemical-resistant. This should be confirmed, 

both in terms of risk estimates described below assuming the exposure reduction provided by 

chemical-resistant gloves, as well as any other PPE requirements based on the end-use product 

acute toxicity profile. 

2.3 Data Deficiencies and Requirements 

The exposure database is sufficient to support Registration Review of nicarbazin and any data 

requirements have been satisfied. 

3.0 Hazard Characterization 

Nicarbazin is a complex of two compounds, 4,4'-dinitrocarbanilide (DNC) and 4,6-dimethyl-2-

pyrimidinol (HOP). DNC is considered to be the active component, whil e HOP aids in 

absorption. Nicarbazin has low acute toxicity, is a moderate eye irritant, and is not a dermal 

irritant or sensitizer. 

Table 3.1: Acute Toxicity Profile for Nicarbazin 

G uideline Study Type MRID #(S) Results Toxicity Category No. 

81-1 Acute Oral [rats) 46416413 LDso> 10,000 mg/kg IV 870. 1000 

81-2 Acute Inhalation f ratsl 464 16415 LCso > 0.147 mgfL IV 

1 http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/occupational-pesticide-handler-exposure-data 

and http ://www 2. e pa .gov /pesticide-sci e nee-and-assessing-pesticide-risks/ o ccu patio na 1-p est ici de-posta pp I ica t ion-exposure 

Page 5 of 14 
870.1200 

8 1-4 Primary Eye Irritation 46416416 Moderate Irritant III 870.2400 frabbitsl 

8 1-5 Primary Dermal Irritation 464 16417 Non-Irritant IV 

870.2500 frabbitsl 

8 1-6 Dermal Sensitization 46416418 Not a sensitizer 870.2600 r guinea pigs l 

Based on the available data submitted to the agency and an available EFSA report, the 

toxicology database for nicarbazin is sufficient for assessing risk. Although the current 40 CFR 

Part 158 Toxicology Data Requirements include 90-day dermal, subchronic inhalation, 

immunotoxicity, and neurotoxicity (acute and subchronic) studies, these studies were not 

submitted for nicarbazin. However, using a weight-of-evidence (WOE) approach, considering all 

avail able hazard and exposure information, the Hazard and Science Pol icy Council (HASPOC) 

detennined that the 2 1 /28-day dermal, subchronic inhalation, immunotoxicity, and neurotoxicity 

(acute and subchronic) are not required to support the registered uses of ni carbazin (Bever, R, 

10/21 /2015; TXR #005726 1). 

Based on the available data, while all effects at 90 days appear to be of minimal severity, an 

increase in toxicity over time is suggested when comparing the 90-day and developmental 

studies in rats. In rabbits, lobulation of the liver was observed in the maternal animals. 

However, due to low incidence and absence of corresponding effects, the toxicological 

significance of this effect is unclear. ln developmental toxicity studies, no developmental 

toxicity was observed in the rabbit. In rats, decreased fetal weights were observed in the 

presence of maternal toxicity (decreased body weights in dams). Therefore, there is no concern 

for pre-natal susceptibility. The available studies did not indicate any concerns for 

neurotoxicity or immunotoxicity. As a non-food use chemical, carcinogenicity studies are not 

required, though no evidence of mutagenicity was observed. 

No effects were observed in studies using the 3: 1 mixture of DNC to HOP or using DNC alone 

including: the chronic oral toxicity studies with a NOA EL of 400 mg/kg in both dogs and rats; 

the reproductive toxicity study with no parental or reproductive effects observed up to the 

highest dose tested of 400 mg/kg/day in rats; and the 90-day oral gavage study with DNC 

showing no effects up to 709 mg/kg/day in rats. Therefore, based on the available data, 

nicarbazin appears to be more toxic than DNC alone, and the 3: l DNC to HOP mixture. 

The LOAEL of 181 mg/kg/day from the 90-day toxicity study is considered appropriate for 

assessing risk for all exposure scenarios. Exposures from different routes should therefore be 

combined for risk assessment when applicable. Since no dermal or inhalation absorption data 

are available, toxicity by both routes is considered to be equivalent to the estimated toxicity by 

the oral route of exposure. 

The standard body weight for the general population (80 kg) was used for all exposure scenarios 

covered in this risk assessment since the endpoints selected were not developmental and/or fetal 

effects. 

Page 6of 14 
A l OX database uncertainty factor was applied for a LOAEL to NOAEL extrapolation. As a 

non-food use chemical with no residential uses and exposure to children not expected, FQPA 

considerations do not apply. Thus, for all exposure scenarios, a 1000-fold UF (1 OX for 

interspecies extrapolation, lOX for intraspecies variation, and lOX UFctb) was applied. 

Table 3.1 Nicarbazin: Summary of Toxicological Doses and Endpoints for Non-Occupational Human Health 

Risk Assessments. 

Level of 

Exposure Point of Uncertainty Concern (LOC) Study and Toxicological Effects Scenario Depa rture Factors for Risk 

Assessments 

Dermal Short- LOAEL = 18 1 UFA= 10 LOC for MOE = 90-Day Oral Toxicity 

Tenn(! to30 mg/kg/day UFH = 10 1000 (EFSA 2010) 

days), UFdb = IO 

LOA EL= 181 mg/kg/day based on Intermediate Tem1 

(1 to 6 months) decreases in body weights, 

erythrocytes, hemoglobin, and 

hcmatocrit. Increases in blood urea 

nitrogen and plasma creatinine. 

Increases in several relative organ 

weights. Tubular degeneration in the 

kidney and degeneration in the 

seminiferous tubule. 

No NOAEL was identified. 

Inhalation Short- LOAEL = 18 1 UFA = 10 LOC fo r MOE= 90-Day Oral Toxici!Y 

Tenn (I to 30 mg/kg/day UFH = 10 1000 (EFSA 2010) 

days), UFdb= 10 

lntem1ediate Tem1 LOAEL= 18 1 mg/kg/day based on 

(I to 6 months) decreases in body weights, 

erythrocytes, hemoglobin, and 

hematocrit. Increases in blood urea 

nitrogen and plasma creatinine. 

Increases in several relative organ 

weights. Tubular degeneration in the 

kidney and degeneration in the 

seminifcrous tubule. 

No NOA EL was identified. 

Po111t of Departure = A data point or an estimated point that is derived from observed dose-response data and used to 

mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human 

exposures. NOA EL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = 

uncertainty facto r. UFA= extrapolation from animal to human (interspecies). UFH = potential variation in 

sensitivity among members of the human population (intraspecies). UFdb = uncertainty due to extrapolation from a 

LOA EL to NOAEL. 

4.0 Exposure and Use Profile 

Table 4.1 below outlines the use profil e for OvoControl P (EPA Reg. No. 80224- 1 ), the only 

product registered containing nicarbazin as the acti ve ingredient. 

Page 7of 14 
Table 4.1 Nicarbazin Use Profile (EPA Reg. No. 80224-1) 

Application Work Use Directions and Use Siteffarget Formulation Equipment Attire/ Rate PPE Limitations 

Commercial and 0.5% ai - Hand 1 ounce of Long - Use only in secured 

industrial granule/bait dispersal product per 5 sleeved areas with limited 

buildings (e.g., - Rotary pigeons shirt, long public access. 

office parks, spreader pants, - Condition pigeons over malls, hospitals, Belly 1 ozl5 pigeons shoes, a period of 5 to 14 days, schools, bridges, - socks, grinder * llb/16oz* starting with small 

airports): 0.5% = gloves. amounts of bait and rooftops or 0.0000625 lb visually observing paved/concrete ai/pigeon whether the pigeons are areas of limited feeding. 

public access - Remove excess bait Product is a 30 after each feeding. lb bag, enough 

to treat 2400 - Discontinue use after 14 

pigeons days if conditioning 

fails. 

5.0 Residential Exposure and Risk Estimates 

Because the product is not specified for use in or around homes, consumer/residential applicator 

exposure is not expected. Additionally, because the label specifies use in secured areas of 

limited public access and directs applicators to observe the pigeon feeding and remove excess 

bait after each feeding, exposures to adults or children following applications are likewise not 

expected. 

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates 

Off-target movement of pesticides can occur via many types of pathways and it is governed by a 

vari ety of factors. Sprays that are released and do not deposit in the appli cation area end up offtarget and can lead to exposures to those it may directly contact. They can also deposit on 

surfaces where contact with residues can eventually lead to indirect exposures (e.g., children 

playing on lawns where residues have deposited next to treated fields). The potential risk 

estimates from these residues can be calculated using drift modeling coupled with methods 

employed for residential risk assessments for turf products. 

Because nicarbazin is both a granule and applied by hand or hand-operated equipment, exposure 

via drift is unlikely to occur. 

7.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk 

Estimates 

Volatilization of pesticides may be a source of post-application inhalation exposure to 

individuals nearby pesticide applications. The agency sought expert advice and input on issues 

related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act 

Scientific Advisory Panel (SAP) in December 2009, and received the SAP's final report on 

Page 8 of 14 
March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/I 20109meeting.html). The 

agency has evaluated the SAP report and has developed a Volatilization Screening Tool and a 

subsequent Volatilization Screening Analysis 

(http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219). During Registration 

Review, the Agency will utilize this analysis to determine if data (i.e., flux studies) or further 

analysis are required for nicarbazin. 

8.0 Occupational Exposure/Risk Characterization 

As a granule/bait pigeon contraceptive used on paved/concrete areas or rooftops of office parks, 

malls, hospitals, schools, bridges, airports, other commercial/industrial buildings/structures, 

dennal and inhalation exposures to nicarbazin are anticipated for occupational handlers (loaders 

and applicators. 

Post-application exposure is not expected because residues on concrete/paved areas are expected 

to be limited, nor are any worker activities in areas previously treated with nicarbazin expected 

that would involve significant hand or body contact with any residues. Therefore, any applicable 

restricted-entry intervals (REis) for nicarbazin would default to technical grade active ingredient 

acute toxicity-based requirements. As the most severe acute toxicity category for nicarbazin is 

Category III, the REI, when applicable according to EPA's Worker Protection Standard, would 

be 12 hours. 

8.1 Occupational Handler Exposure and Risk Estimates 

HED uses the tenn handlers to describe those individuals who are involved in the pesticide 

application process. HED believes that there are distinct job functions or tasks related to 

applications and exposures can vary depending on the specifics of each task. Job requirements 

(amount of chemical used in each application), the kinds of equipment used, the target being 

treated, and the level of protection used by a handler can cause exposure levels to differ in a 

manner specific to each appli cation event. 

The quantitative exposure/risk assessment developed for occupational handlers of nicarbazin is 

based on applications of granules by hand or with hand-operated equipment such as a belly 

grinder or rotary spreader. 

Occupational Handler Exposure Data and Assumptions 

A series of assumptions and exposure factors served as the basis for completing the occupational 

handler risk assessments. Each assumption and factor is detailed below on an individual basis. 

Application Rate and Amount of Product Handled: 

As outlined in Table 4.1 , the application rate used in this assessment is based on the product 

label specifying a maximum rate of l ounce of product per 5 pigeons. Applying 0.5% nicarbazin 

will result in an application rate of approximately 0.0000625 lb ai per pigeon. For the purposes 

of risk assessment it is assumed that an entire single product (i.e., a 30 lb bag) is used per day, or 

approximately 0.15 lb nicarbazin. This would treat approximately 2,400 pigeons. 

Page 9of14 
Unit Exposures: 

It is the policy of HED to use the best available data to assess handler exposure. Sources of 

generic handler data, used as surrogate data in the absence of chemical-specific data, include 

PHED 1.1 and the ORETF database. Some of these data are proprietary (e.g., ORETF data) and 

subject to the data protection provisions of FIFRA. The standard values recommended for use in 

predicting handler exposure that are used in this assessment, known as "unit exposures'', are 

outlined in the "Occupational Pesticide Handler Unit Exposure Surrogate Reference Table2

'', 

which, along with additional information on HED policy on use of surrogate data, including 

descriptions of the various sources, can be found at the Agency website3. 

Exposure Duration: 

HED typically classifies exposures from I to 30 days as short-term and exposures 30 days to six 

months as intermediate-term. Exposure duration is detennined by many things, including the 

exposed population, the use site, the pest pressure triggering the use of the pesticide, and the 

cultural practices surrounding that use site. For most agricultural uses, it is reasonable to believe 

that occupational handlers will not apply the same chemical every day for more than a onemonth time frame; however, there may be a large agribusiness and/or commercial applicators 

who may apply a product over a period of weeks (e.g., completing multiple applications for 

multiple clients within a region). Thus, both short- and intermediate-tenn exposures are 

anticipated for nicarbazin; long-term exposures not expected. 

Mitigation/Personal Protective Equipment: 

The nicarbazin label requires a long-sleeved shirt, long pants, shoes, socks and gloves. For the 

purposes of risk assessment, the gloves are assumed to be chemical-resistant, though, per 

standard HED practice, risk estimates are also provided at baseline work attire (i.e., no chemicalresistant gloves or other PPE). Inhalation exposure is assessed assuming no respiratory 

protection. 

Occupational Handler Non-Cancer Exposure and Risk Estimate Equations 

The algorithms used to estimate non-cancer exposure and dose for occupational handlers can be 

found in Appendix A. 

Combining Exposures/Risk Estimates 

Dermal and inhalation risk estimates were combined in this assessment, since the toxicological 

effects for these exposure routes were similar. Dermal and inhalation risk estimates were 

combined using the following formula: 

Total MOE = Point of Departure (mg/kg/day) -;- Combined Dermal + Inhalation dose (mg/kg/clay) 

2 Available: http://www2.epa.gov/sites/production/files/2015-09/documents/handler-exposure-table-20 15.pdf 

3 Available: http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/occupational-pesticide-handlerexposure-data 

Page 10of14 
Summary of Occupational Handler Non-Cancer Exposure and Risk Estimates 

Assuming label-required work attire and PPE, no risks of concern from combined dermal and 

inhalation exposure were identified (MO Es 2: 1000). 

Table 8. 1.1 presents detailed exposure and risk calculations. 

Page 11 of 14 
Table 8.1.1. Summary of Occupa tiona l Handler Risk Estimates for Nicarbazin 

Denna! Inhalation Combined 

Exposure Amount Unit Exposure Dose (mg/kg/day)4 Unit MOE5 

Equipment App Rate1 Handled/ Area (ug/Jb ai)3 Dose (LOC = 1000) Scenario Treated2 Exposure (mg/kg/day)4 SUNG/ SUGIN SUNG SUG SUNG SUG (ug/lb ai)3 

NR R 

Hand 104000 71000 0.195 0.134 470 0.00088 930 1.400 Loading I dispersal 

applying Belly granules to 0.0000625 2400 pigeons 10000 9300 0.0 188 0.0175 62 0.000 12 9,500 9,900 

paved grinder lb ai/pigeon (entire 30 lb bag) 

/concrete Rotary areas spreader 440 240 0.00083 0.00045 10 0.000019 220,000 380,000 

Bast'Cl on r'-gistercd lnbcl on registered labels ou1lincd in Tnble 4.0. 

2 Exposure Science Advisory Council Policy ff9. I and infom1ation provided on labels 

3 Based on the ··occupa1ional P<.-sticidc Handler Unit Exposure Surrogate Reference Table" (Scptcrnhcr 20 15). SL = single layer (long-sleeve shirt. pantS. shoes/socks. NG = no gloves. G = gloves. 

N R = no respirator. 

4 Dcnnal/lnhalation Dose = Unit Exposure (Jtg/lb ai) x Conversion Factor(0.001 mg/Jig) x Application Rme " Arca Trcat<.'Cl" 100% absorption + BW (kg). 

5 Combined MOE = POD g/kg/day) ~ [D1o:nnal Dose (mg/kg/day+ Inhalation Dose (mg/kg/day)] 

Page 12of14 
Appendix A. Summary of Occupational Non-cancer Algorithms 

OCCUPATIONAL NON-CANCER HANDLER ALGORITHMS 

Potential daily exposures for occupational handlers are calculated using the following formulas: 

E=UE *AR *A * 0.001 mglug 

where: 

E = exposure (mg ai/day), 

UE = unit exposure (μg ai/lb ai), 

AR = maximum application rate according to registered labels (lb ai A, lb ai/gal, etc.), 

and 

A = area treated or amount handled (e.g., A/day, gal/day). 

The daily doses are calculated using the followi ng formu la: 

where: 

ADD = 

E 

AF 

BW = 

ADD= 

E*AF 

BW 

average daily dose absorbed in a given scenario (mg ai/kglday), 

exposure (mg ai/day), 

absorption factor (dennal and/or inhalation), and 

body weight (kg). 

Margin of Exposure: Non-cancer risk estimates for each application handler scenario are 

calculated using a Margin of Exposure (MOE), which is a ratio of the toxicological endpoint to 

the daily dose of concern. The daily dermal and inhalation dose received by occupational 

handlers are compared to the appropriate POD to assess the risk to occupational handlers for 

each exposure route. All MOE values are calculated using the following formula: 

where: 

MOE = 

POD 

MOE= --ADD 

margin of exposure: value used by HED to represent risk estimates (unitless), 

Page 13 of14 
POD 

ADD = 

point of departure (mg/kg/day), and 

average daily dose absorbed in a given scenario (mg ai/kg/day). 

Page 14 of 14