Document ID: EPA-HQ-OPP-2008-0550-0005
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-10-08T04:00Z

Overview of the Ecological Risk Assessment Process 

in the Office of Pesticide Programs, 

U.S. Environmental Protection Agency 

__________

Endangered and Threatened Species Effects Determinations

Office of Prevention, Pesticides and Toxic Substances

Office of Pesticide Programs

Washington, D.C.

January 23, 2004

Acknowledgments

Authors, in alphabetical order:

Russell Jones, Office of Pesticide Programs, Biopesticides and Pollution
Prevention Division

John Leahy, Office of Pesticide Programs, Special Review and
Reregistration Division

Michele Mahoney, Office of Pesticide Programs, Environmental Fate and
Effects Division

Linda Murray, Office of Pesticide Programs, Registration Division

Edward Odenkirchen, Office of Pesticide Programs, Environmental Fate and
Effects Division

Richard Petrie, Office of Pesticide Programs, Antimicrobial Division

Carol Stangel, Office of Pesticide Programs, Special Review and
Reregistration Division

Ingrid Sunzenauer, Office of Pesticide Programs, Environmental Fate and
Effects Division

Zigfridas Vaituzis, Office of Pesticide Programs, Biopesticides and
Pollution Prevention

Division

Arthur Jean Williams, Office of Pesticide Programs, Field and External
Affairs Division

Reviewers, in alphabetical order:

Steven Bradbury, Office of Pesticide Programs, Environmental Fate and
Effects Division

William Jordan, Office of Pesticide Programs

Paul Mastradone, Office of Pesticide Programs, Registration Division

Karen McCormack, Office of Pesticide Programs, Environmental Fate and
Effects Division

Larry Turner, Office of Pesticide Programs, Field and External Affairs
Division

Scientists in the Office of Research and Development

Table of Contents

 TOC \f 

I.  Purpose and Organization of This Document	7

II.  Statutory Framework	8

A.  Statutory Authority	8

B.  Authority to Require Data	8

C.  Definitions and Types of Pesticides	9

III.  Overview of the Office of Pesticide Programs	11

A.  Mission of the Office of Pesticide Programs	11

B.  Organizational Structure of the Office of Pesticide Programs	11

1.  Science-based Divisions	14

2.  Risk Management Divisions	14

3.  Science-based and Risk Management Divisions	15

4.  Other Divisions	15

C.  Regulatory Processes	16

1.  Section 3 Registrations	16

2.  Experimental Use Permits	17

3.  Emergency Exemptions	17

4.  Special Local Need Registrations	19

5.  Reregistration Process	19

6.  Registration Review	21

D.  Addressing Potential Concerns Related to Listed Species	21

IV.  Overview and Organization of the Environmental Fate and Effects
Division	23

A.  The Environmental Fate and Effects Division’s Procedures	24

B.  Data Requirements and Other Data Sources	25

C.  Processes to Support Sound Science	26

1.  Agency Guidance	26

a.  Guidelines for Ecological Risk Assessments	26

b.  Risk Characterization Handbook	26

c.  Peer Review Handbook	26

2. Tools to Promote Sound Science	27

a.  Pesticide Assessment Guidelines	27

b.  Standard Evaluation Procedures	27

c.  Databases	27

d.  Technology Teams	29

3. Internal Peer Review Mechanisms	29

a.  Data Evaluation Records	29

b.  Risk Assessments and Risk Characterizations	29

c.  Science Policy Panel	30

4.  External Peer Review and Scientific Advisory Panel	30

V.  Overview of OPP’s Screening-Level Ecological Risk Assessment
Process for Aquatic       Life, Wildlife, and Plants	31

A.  Problem Formulation	31

1.  Defining the Regulatory Action	31

2. The Nature of the Chemical Stressor Considered in the Risk Assessment
32

3.  Pesticide Use Characterization	33

4.  Identification of Assessment Endpoints	34

a.  Direct Effects	34

b.  Indirect Effects for Listed Species	34

c.  Effects on Listed Species Critical Habitat	35

5.  Measures of Effects and Exposure: The Use of Surrogate Organisms	35

6.  Identification of Data Gaps	36

B.   Analysis Phase	37

1.  Exposure Characterization	37

a.  Fate and Transport Data Requirements and Study Evaluation	37

b.  Aquatic Organism Exposure Modeling	40

(1).  General Approach	40

(2).  Special Aquatic Exposure Methods for Pesticide 

Formulations 	42

c.  Terrestrial Organism Exposure Modeling	43

(1).  General Approach	43

(2).  Special Terrestrial Exposure Methods for Pesticide Formulations	44

d. Non-Target Plant Exposure Modeling	44

2.  Effects Characterization	45

a.  Registrant-Submitted Studies for Direct Effects of Pesticides	47

b.  Open Literature Studies for Direct Effects of Pesticides	47

(1).  ECOTOX	47

(2).  OPP Strategy for Conducting Literature Searches	48

c.  Open Literature Studies for Indirect Effects of Pesticides	49

d.  Open Literature Studies for Critical Habitat Evaluations	49

C.   Risk Characterization	49

1.  Integration of Exposure and Effects Data - The Risk Quotient for
Direct 		Effects	49

2.   Levels of Concern for Direct Effects - The Policy Tool for
Interpreting Risk Quotients for Direct Effects	50

3.  Comparison of Field and Laboratory Data for Direct Effects	51

4.  Indirect Effects Characterization for Listed Species	52

a. Indirect Effect Analyses Where One or More Animal Taxonomic Group RQs
Exceed the Endangered Species LOC	52

b. Indirect Effects Where One or More Plant Taxonomic Group RQs Exceed
the Endangered Species LOC	53

5.  Critical Habitat for Listed Species	54

6.  Description of Assumptions, Uncertainties, Strengths, and
Limitations of the Assessment	54

a.  Assumptions and Limitations Related to Exposure for All Taxa	54

b. Assumptions and Limitations Related to Exposure for Aquatic Species
55

(1).  Location of Species and Receiving Waters to Treated Field	55

(2).  Exposure for Aquatic Species Is Through the Dissolved Phase	55

(3).  Dissipation in the Modeled Water Body	55

(4).  Averaging Times for Aquatic Exposure	56

(5).  A Well-Mixed Pond	56

(6).  Watershed to Pond Ratio	56

(7).  100 Percent Pesticide Treatment of the Pond Watershed	57

(8).  Frequency of Exposure During a Given Year - 1 in 10 Year Return
Frequency	57

(9).  Dilution of Sediment	57

(10).  Spray Drift	58

c. Assumptions and Limitations Related to Exposure for Terrestrial
Animals	60

(1).   Location of Wildlife Species	60

(2).  Routes of Exposure	60

(3).  Incidental Pesticide Releases Associated with Use	62

(4).  Residue Levels Selection	62

(5).  Dietary Intake - The Differences Between Laboratory and Field
Conditions	63

d. Assumptions and Limitations Related to Effects Assessment	64

(1).  Sublethal Effects	64

(2). Age Class and Sensitivity of Effects Thresholds	65

(3).  Use of the Most Sensitive Species Tested	66

e.  Assumptions Associated with the Acute LOCs	67

VI.  Overview of OPP’s Species-specific Ecological Risk Assessment
Process for Aquatic        Life, Wildlife, and Plants	69

A.  Overview and Organization of FEAD	69

B. Purpose of the Species-Specific and Habitat-Specific Assessments	69

C.  Effects Determinations	70

D.  Information and Data Sources Used in the Species-specific and
Habitat-specific Assessments	71

1.  “DANGER” Program	71

2.  Biological Requirements and Habits of Listed Species	71

3.  Sub-county Commodity Information	72

4.  Geographic Features That May Preclude Exposure	72

5.  Incident Information	72

6.  Sales and Use Information	72

7.  Local Use Practices	73

8.  Monitoring Data	73

E.  Exposure Characterization in the Species-Specific and
Habitat-Specific Assessments	73

1.  Geographic Proximity	73

a.  A “DANGER” Query	73

b.  Sub-county Use of the Pesticide	73

2.  Refine Exposure Estimates Using Specific Assessment Methodologies	74

3.  Refine Exposure Based on Biological and Habitat Requirements	74

F.  Risk Characterization	75

1.  Incident Information	75

2.  Sales and Use of the Pesticide	76

3.  Local Use Practices	76

4.  Monitored Levels in the Environment	76

G.  Assumptions	76

H.  Environmental Baseline and Analysis of Cumulative Effects	77

VII.  List of Support Documents	79

VIII.  References	83

Appendices

Appendix A.	Overview of OPP’s Screening-Level Ecological Risk
Assessment Process for Antimicrobial Pesticides	85

Appendix B.	Overview of OPP’s Screening-Level Ecological Assessment
Process for Biological Pesticides 	91

 

Overview of the Ecological Risk Assessment Process in the 

Office of Pesticide Programs, Environmental Protection Agency 

I.  Purpose and Organization of This Document tc \l1 "I.  Purpose and
Organization of This Document 

The purpose of this document is to provide an overview of the
Environmental Protection Agency’s (EPA) ecological risk assessment
process for the evaluation of potential risk to endangered and
threatened (listed) species from exposure to pesticides.  The
assessments described in this document are conducted by the Office of
Pesticide Programs (OPP).  

Organized into eight sections and two appendices, this document begins
with a description of the purpose and organization of the document
(Section I).  It continues with a brief overview of the statutory
framework under which OPP operates (Section II), followed by a
discussion of  OPP’s mission and organizational structure, and basic
information about OPP’s regulatory processes (Section III).  Section
III also acknowledges the importance of evaluating regulatory actions
for their potential impact to listed species and briefly describes the
steps being taken to ensure that listed species concerns are addressed.

Section IV provides an overview of the Environmental Fate and Effects
Division (EFED), which conducts most of the initial screening-level
assessments to evaluate the potential impact of pesticides on non-target
species, including listed species.  This section addresses EFED’s
procedures, data requirements, and processes to support the development
of ecological assessments based on sound science.  

Section V provides a comprehensive review of EFED’s screening-level
assessment process, which is based on risk assessment procedures
outlined in guidance documents and standard evaluation procedures.  If a
pesticide is determined to potentially impact listed species, a
species-specific assessment, which is described in Section VI, is
conducted by another OPP division, the Field and External Affairs
Division (FEAD). 

Sections V and VI summarize the screening-level and species-specific
assessments that are generally conducted in OPP.  It should be noted,
however, that the ecological risk assessment process within OPP may, on
a case-by-case basis, incorporate additional methodologies, models, and
lines of evidence that are technically appropriate for risk management
objectives.  Examples of additional information and methodologies
include monitoring and incident data and evaluation of routes of
exposure not routinely considered, but suggested by other lines of
evidence.

Finally, the document concludes with a list of support documents
(Section VII), references (Section VIII), and appendices.

II.  Statutory Framework tc \l1 "II.  Statutory Framework 

A.  Statutory Authority tc \l2 "A.  Statutory Authority 

EPA regulates pesticides under two major federal statutes: the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal
Food, Drug, and Cosmetic Act  (FFDCA), both amended by the Food Quality
Protection Act (FQPA) of 1996.  Under FIFRA, pesticides intended for use
in the United States must be registered (licensed) by EPA before they
may be sold or distributed in commerce.  EPA will register a pesticide
if scientific data provided by the applicant show that, when used
according to labeling directions, it will not cause “unreasonable
adverse effects on the environment”. (FIFRA defines “unreasonable
adverse effects on the environment” as “any unreasonable risk to man
or the environment, taking into account the economic, social and
environmental costs and benefits of the use of any pesticide .....”) 
Under FFDCA, the Agency is responsible for setting tolerances (maximum
permissible residue levels) for any pesticide used on human food or
animal feed.

With the passage of the Food Quality Protection Act (FQPA) in 1996, both
major pesticide statutes were amended to establish a more consistent,
protective regulatory scheme grounded in sound science.  FQPA mandated a
single, health-based standard for setting tolerances for pesticides in
foods; provided special protections for infants and children; expedited
approval of safer pesticides; created incentives for the development and
maintenance of effective crop protection tools; and required periodic
re-evaluation of pesticide registrations and tolerances to ensure that
the scientific data supporting pesticide registrations would remain
up-to-date in the future. It should be noted that FQPA also limited the
consideration of benefits when setting tolerances.  FQPA did not address
the consideration of ecological risk.

For this document, the focus will be on environmental risks, which are
regulated under FIFRA.

B.  Authority to Require Data tc \l2 "B.  Authority to Require Data  

By law, the Agency has the authority to obtain data under three
provisions of FIFRA:

FIFRA 3(c)(1)(F) - Authorizes the Agency to require data to support an
application for registration of a pesticide.  OPP’s data requirements
are set forth in 40 CFR Part 158, but EPA has broad authority to ask for
additional data or waive requirements, as appropriate. These data
requirements are discussed under Section IV of this document.

FIFRA 3(c)(2)(B) - Provides the authority to require additional data on
currently registered products.  These data must be “required to
maintain in effect an existing registration of a pesticide.”  If EPA
imposes a data requirement under this authority, EPA must allow enough
time to design the study and generate data.  In addition, EPA must
comply with the Paperwork Reduction Act. 

FIFRA Section 6(a)(2) - Requires that pesticide registrants inform the
Agency of any relevant adverse effects information relating to their
products, even though it was not  formally requested by EPA. 
Information reportable under this provision includes new information
derived from scientific studies, such as efficacy failures of
antimicrobial products and pest resistance.  Incidents of adverse
effects resulting from the use of pesticide products are also reported. 
 The information collected under 6(a)(2) is tracked and regularly
distributed to the various divisions in OPP, as appropriate. [See 40 CFR
15 and http://www.epa.gov/pesticides/fifra6a2/ for more information
concerning EPA’s published guidelines and regulations for Section
6(a)(2).]

C.  Definitions and Types of Pesticides tc \l2 "C.  Definitions and
Types of Pesticides 

Based on the Code of Federal Regulations (CFR), a pesticide is defined
as:

“Any substance or mixture of substances intended for preventing,
destroying, 

repelling, or mitigating any pest, or intended for use as a plant
regulator, 

defoliant, or dessicant....” (40 CFR 152.3).

Substances that are not covered in this definition include, but are not
limited to, deodorizers, non-toxic physical barriers against pests,
fertilizers or other plant nutrient substances which do not target pest
species.  Some products meeting the definition of a pesticide are exempt
from requirements of FIFRA, such as those for human drug use only,
pesticide treated articles (clothing, paints, etc.), pheromones used in
traps, food preservatives, or natural repellants such as cedar wood  (40
CFR 152).

Based on 40 CFR 152.3, an active ingredient and an inert ingredient,
respectively, are defined as follows:

“Any substance (or group of structurally similar substances if
specified by the Agency) that will prevent, destroy, repel or mitigate
any pest, or that functions as a plant regulator, dessicant, or
defoliant within the meaning of FIFRA section 2(a), except as provided
in §174.3 of this chapter.”

“Any substance (or group of structurally similar substances if
specified by the Agency), other than an active ingredient, which is
intentionally included in a pesticide product, except as provided in
§174.3 of this chapter.”

Many different types of pesticides are available.  They may be grouped
according to the pests they control, their use pattern, or their
chemical class.  The following list provides some examples of the
categories of pesticides that are grouped according to the pests they
control: 

Insecticides - act pesticidally against the growth or survival of
insects.  Also includes specific types such as miticides, mosquito
larvicides or adulticides;

Herbicides - act pesticidally against plants, weeds, or grasses;

Rodenticides - act pesticidally against rats or other rodents;

Avicides - act pesticidally against damaging bird populations;

Fungicides - act pesticidally against fungi on food or grain crops;

Nematicides - act pesticidally against nematodes;

Fumigants - gaseous pesticides used for invertebrate and fungal control;

Antimicrobials - act pesticidally against microscopic organisms on a
variety of sites;

Plant Growth Regulators - accelerate or retard plant growth rates;

Insect Growth Regulators - retard insect growth;

Biopesticides - naturally occurring substances with pesticidal
properties, including microbial pesticides, biochemical pesticides and
plant incorporated protectants;

Piscicides - act pesticidally against unwanted or invasive fish
populations; and

Molluscides - act pesticidally against slugs, snails, or bivalves.

Pesticides may also be categorized into the following general use
patterns in order to determine registration data requirements:
terrestrial, aquatic, greenhouse, forestry, domestic outdoor, and indoor
(40 CFR 158).  The terrestrial, aquatic, and greenhouse patterns are
further divided into food crop and nonfood applications. 

Pesticides that have similar chemical structures often have similar
modes of action, as well as comparable fate and transport properties. 
Such chemicals may be grouped in the same chemical class.  Some examples
of chemical classes include the following:

Insecticides: chloronicotinyl compounds (e.g., imidacloprid, nicotine),
N-methyl carbamates (e.g., carbaryl, aldicarb), organophosphorus
compounds (e.g., chlorpyrifos, diazinon), and pyrethroids (e.g.,
cyfluthrin, cypermethrin), and others.

Herbicides:  benzoic acids (e.g., dicamba), chloroacetanilides (e.g.,
alachlor, metolachlor), chlorophenoxy acids/esters (e.g., 2,4-D, MCPA),
imidazolinones (e.g., imazamox, imazapyr), sulfonylureas (e.g.,
bensulfuron-methyl, rimsulfuron), thiocarbamates (e.g., butylate,
molinate), and triazines (e.g., atrazine, simazine), and others.

Fungicides: benzimidazoles (e.g., benomyl, thiabendazole), carboxamides
(e.g., carboxin, flutolanil), and dithiocarbamates (e.g., maneb, ziram),
and others.

III.  Overview of the Office of Pesticide Programs tc \l1 "III. 
Overview of the Office of Pesticide Programs 

A.  Mission of the Office of Pesticide Programs tc \l2 "A.  Mission of
the Office of Pesticide Programs 

EPA’s overarching mission is to protect human health and to safeguard
the environment – air, water, and land – upon which life depends. 
An important component of this goal is the protection of  human health
and the environment from unreasonable adverse effects resulting from the
use of pesticides and to assure that pesticide residues that may occur
in food are safe.  

OPP’s mission is both challenging and complex. OPP regulates the use
of all pesticides in the United States and establishes maximum levels
for pesticide residues in food, thereby safeguarding the nation's food
supply.  Pesticides play a role in many aspects of everyday life, from
agriculture and greenhouses to lawns, swimming pools, hospitals, and
food service establishments. There are about 20,000 registered pesticide
product formulations, containing approximately 675 active ingredients
and 1,835 other ingredients. About 470 pesticide active ingredients are
used in agriculture, and EPA has established more than 9,000 tolerances
(maximum allowable residue limits) for pesticides that may be present in
food.

EPA's regulation of pesticides directly or indirectly affects
approximately 30 major pesticide producers, another 100 smaller
producers, 2,500 formulators, 29,000 distributors and other retail
establishments, 40,000 commercial pest control firms, one million farms,
three and a half million farm workers, several million industry and
government users, and virtually all households.  

B.  Organizational Structure of the Office of Pesticide Programs tc \l2
"B.  Organizational Structure of the Office of Pesticide Programs 

To fulfill its mission, OPP has nine divisions and the immediate office
of OPP’s Office Director. Approximately 800 people carry out a wide
range of activities related to pesticide regulation and risk management.
In addition, a large number of people in other EPA offices, including
EPA’s regional offices, provide administrative, legal, enforcement,
and research support.  Figure 1 provides a graphical representation of
the organizational structure, which is described later in this section.

 	It should be noted that in OPP, a distinction is made between the role
of the risk assessor and risk manager.  Risk assessors use information
and data concerning pesticide exposure and human and ecological effects
to estimate the likelihood of adverse outcomes with varying pesticide
use scenarios.  Risk managers determine how the pesticide will be
regulated.  In regulating ecological effects, the regulatory decision is
based on the results of the risk assessment and potential mitigation
options, but may also include the integration of social considerations
and economic factors (benefits information), and legal requirements. 
Trade-offs between different regulatory actions are evaluated, and value
judgments applied to reach a decision.

Risk management addresses a variety of considerations that range from
scientific to socio-economic considerations.  The risk analysis focuses
on providing an unbiased evaluation of risk, with assumptions and
uncertainties clearly articulated.  By separating the functions of the
pesticide risk assessment and risk management processes, within the
broader risk management framework, the integrity and transparency of the
scientific analyses are maintained. 

The policy regarding the interface between risk assessment and risk
management grew out of a National Research Council report in 1983,
referred to as the “Red Book”, which emphasized the distinction
between the two functions (National Research Council, 1983.)  The Red
Book proposed a strong separation of risk assessment and risk
management, but also recognized the need and importance of continual
interaction between the functions.  Although the Red Book focused on
human health, the policy was expanded to address ecological risk as
well. 

Figure 1: OPP Organizational Structure

	

Office of the Director

	

	

	

	

	

	

	

Environmental Fate and Effects Division

Risk Assessment	

	

Health Effects Division

Risk Assessment

	

	

	

	

Registration Division

Risk Management	

	

Special Review and Reregistration Division

Risk Management

	

	

	

	

Biopesticides and Pollution Prevention Division

Risk Assessment and Risk Management	

	

Antimicrobials Division

Risk Assessment and Risk Management

	

	

	

	

Biological and Economic Analysis Division

Usage Data, Benefits Analysis, and Chemistry Labs	

	

Field and External Affairs Division

Field Programs, Policy, and Regulation Support and Communications

	

	

	

	

Information Resources and Services Division

Information Management and Systems Support

	

	

	

1.  Science-based Divisions tc \l3 "1.  Science-based Divisions 

The following divisions focus primarily on conducting the risk and
benefit assessments for conventional pesticides; they do not perform
risk management functions.  The results of the science assessments,
including the ecological risk assessment for listed species, are
forwarded to the risk management divisions discussed in the next
section. 

Environmental Fate and Effects Division (EFED) - Conducts
screening-level risk assessments to assess the ecological risk to
non-target species, including the potential impact on listed species,
and conducts refined ecological risk assessments.  (See Section V for an
overview of OPP’s screening-level assessment process.)  In addition,
EFED evaluates drinking water exposure and sends its evaluations to the
Health Effects Division to be considered in their human health risk
assessments.

Health Effects Division (HED) - Reviews data on pesticide human health
effects and characterizes and assesses risks to humans and domestic
animals, which are considered in risk management decisions.  As part of
the assessment process, HED’s Metabolism Assessment Review Committee
(MARC) considers whether pesticide metabolites and/or breakdown products
are of toxicological concern and should be included in the dietary
exposure/risk assessment and/or tolerance expression for foods and
livestock feeds. In addition, a screening methodology has been developed
to evaluate lower toxicity inert and active ingredients to determine
that there is a reasonable certainty that no harm will result from the
aggregate exposure to the pesticide residues before granting a tolerance
or exemption from the requirement of a tolerance. 

HED does not participate directly in the development of an ecological
risk assessment.  However, HED does review acute mammalian toxicity data
conducted on the active ingredient and formulations as well as
two-generation reproductive toxicity tests, which are used by EFED to
characterize mammalian wildlife toxicity.  HED also reviews pesticide
residue dissipation in food crops and animal feed items, which are used
to estimate foliar dissipation half-lives for multiple application
exposure modeling for wildlife. In addition, the information from the
MARC (see Section V. B.2) and from the evaluation of lower toxicity
inert and active ingredients (see Section V.A.2) may be useful for
evaluating pesticide impacts to ecological resources.

Biological and Economic Analysis Division (BEAD) - Assesses pesticide
use and benefits information and operates analytical chemistry and
antimicrobial testing laboratories. 

2.  Risk Management Divisions tc \l3 "2.  Risk Management Divisions 

The Registration Division and Special Review and Reregistration Division
are responsible for making the final risk management decision on
conventional pesticides, primarily through the registration and
reregistration processes.  These divisions do not conduct risk
assessments.							

Both divisions consult with HED and EFED on questions related to the
human and environmental risk assessments, respectively, and potential
mitigation options once they have received the risk assessments and have
begun to develop the regulatory decision.  If necessary, a risk
assessment may be conducted again at the request of the risk management
division.  This may be necessary because of changes made to the
registration related to mitigation options, which could alter the
results of the assessment. 

Registration Division (RD) - Coordinates and manages the regulatory
actions involving the entry into the market place of new conventional
pesticide products.  These actions include the registration of new
pesticide products, new uses of existing pesticide products, product and
label amendments, experimental use permits, tolerances, and emergency
exemptions based upon scientific evaluation of data and other
considerations.

Special Review and Reregistration Division (SRRD) - Coordinates and
manages the reregistration of existing pesticides and reassessment of
tolerances based upon a scientific evaluation of data and other
considerations.

3.  Science-based and Risk Management Divisions tc \l3 "3. 
Science-based and Risk Management Divisions 

In OPP, two divisions perform both risk assessment and risk management
functions.  It should be noted, however, that the role of risk assessor
and risk manager in these divisions are never assumed by the same
person.  

Antimicrobials Division (AD) - Provides full regulatory service for
antimicrobial pesticides.  This includes the registration and
reregistration processes; conducting assessments for human
health/dietary risk; residential and industrial worker exposure,
environmental fate and ecological effects, drinking water exposure,
product and residue chemistry, and the efficacy of public health
pesticides.  

Biopesticides and Pollution Prevention Division (BPPD) - Focuses on
biologically-based pesticides and measures that will reduce pesticide
risks.  BPPD’s functions include  risk and benefit assessments,  risk
management, tolerance reassessment, and the Pesticide Environmental
Stewardship Program (PESP).  PESP is a voluntary partnership between EPA
and the pesticide user community to reduce risk from pesticide use in
agricultural and non-agricultural settings.

4.  Other Divisions tc \l3 "4.  Other Divisions 

The remaining two divisions provide unique support functions for OPP.  

FEAD - Coordinates OPP’s policies and regulatory development,
international and field programs, such as Certification and Training,
Agricultural Worker Protection Program, and others.  FEAD also
administers and coordinates the field implementation of the  Endangered
Species Protection Program and conducts species-specific risk
assessments for listed species and their designated critical habitat. 
(See Section VI for further detail on the refined assessment process.) 
In addition, FEAD provides region/state/tribal coordination and
assistance, legislation and Congressional interaction, and communication
and outreach activities.

Information Resources and Services Division (IRSD) - Provides
information and computer support for OPP, maintains OPP’s Web site and
OPP databases, handles the Public Docket, and processes FIFRA section
6(a)(2) submissions. 

C.  Regulatory Processes tc \l2 "C.  Regulatory Processes 

The two main regulatory processes in OPP are registration and
reregistration.  Registration focuses on decisions that allow new
pesticide products to enter the market place or that allow registrants
to make changes to the way existing pesticide products are sold,
distributed, or used.  While many registration decisions involve minor
changes or applications for new products that are identical to currently
registered pesticides, EPA devotes considerable resources to the review
of applications involving new active ingredients and applications
involving new uses of currently registered pesticides.

Reregistration is the review of older pesticides to ensure that they
meet current health, safety, and environmental standards.  The goal is
to update labeling and use requirements and reduce risks associated with
older pesticides, which were registered when the standards for
government approval were less stringent than they are today. 	

1.  Section 3 Registrations tc \l3 "1.  Section 3 Registrations  

Section 3 of FIFRA authorizes EPA to register new pesticide products and
new uses of existing pesticide products for use in the United States. 
In registering pesticide products, EPA may place restrictions on the
site or crop on which it is used; the method, amount, frequency, and
timing of its use; and the storage and disposal practices. Some
pesticides may be registered for more limited use in certain states.  In
addition, States, Tribes and Territories can place further restrictions
on EPA-registered pesticide products used or sold within their own
jurisdictions.  

For a Section 3 registration action, the pesticide manufacturer submits
to EPA a  registration application, which includes the following
information:

Required test data;

Information concerning the manufacturing process;

Product chemistry;

Human and environmental risk data packages;

Tolerance information, consisting of information about pesticide
residues on food; and

Labeling information.  

RD processes the application and tracks it. A project manager is
assigned who: 

Completes a detailed review of the application;

Assigns and coordinates the appropriate scientific review;

Sets priorities and a timetable;

Coordinates administrative action; and

Communicates with the pesticide applicant or registrant concerning the
review of its application.

RD assigns the scientific review to HED for an evaluation of human
health risks and to EFED for evaluating environmental risks, including
potential risks to listed species. HED integrates all the human health
effects and exposure data into a comprehensive health risk assessment to
assess the potential impact that the pesticide product or active
ingredient will have on the human population.  At the same time, EFED
integrates scientific ecological effects and exposure information into
an environmental risk assessment to assess potential impacts on the
environment.  Both the health and environmental risk assessments undergo
a process of internal peer review by scientific experts. 

RD’s policy is to send forward all new chemicals submitted for a
Section 3 registration to EFED and HED for a complete scientific review.
  For ecological risk, EFED provides an initial review and risk
assessment for non-target species, including listed species.  This
assessment is conducted using data, which are required based on the uses
of the pesticide. 

Some pesticide uses, such as indoor application, are screened in RD to
determine if there is a potential exposure to non-target organisms.  If
there is no exposure, these uses may not require environmental fate and
ecotoxicity data or a full scientific review.  For example, some
specialized uses, such as indoor greenhouse applications, are screened
to determine if there is a potential to effect non-target organisms
through pesticide disposal.  If not, data are not required and an
ecological assessment is not conducted.

Section 3 amendment actions are screened in Registration Division to
determine if there is an obvious change from the present labeled use. 
Those actions which indicate a change in the use are sent to the science
divisions for review.

In cases where EFED’s screening-level ecological risk assessment
raises potential concerns related to listed species, FEAD conducts a
species-specific evaluation to refine the assessment.  EPA is
implementing internal procedures to ensure that FEAD is routinely
notified and has an opportunity to conduct its analysis if potential
concerns related to listed species are identified. 

After EFED and HED submit their risk assessments to the Registration
Division, RD reviews the risk assessments and develops potential risk
mitigation measures.  RD makes a registration determination based on the
statutory standards of FIFRA and FFDCA. If the application fails to meet
these standards, RD notes the need for more or better data, labeling
modifications, and/or use restrictions, and communicates the
deficiencies to the applicant.  If the application is approved, EPA will
establish a tolerance if the pesticide is intended for use on food or
feed and publishes a notice in the Federal Register. 

2.  Experimental Use Permits tc \l3 "2.  Experimental Use Permits   

Under FIFRA section 5 and the regulations (40 CFR 172), EPA may
authorize field testing of unregistered pesticides through an
experimental use permit (EUP).  Generally the Agency issues EUPs for
field experimentation involving 10 acres or more of land or 1 acre or
more of surface water.  The EUP establishes conditions for limiting the
transportation, application, and disposal of unregistered test products.
 The granting of an EUP also limits the sale and distribution of the
test product only between approved participants in the test program, and
use of the test product under conditions specified in the EUP. 
Pesticide companies typically request EUPs for efficacy testing and/or
crop-specific residue chemistry data. Use-specific data are required to
support an EUP, but are more limited in scope than for a Section 3. 
These data requirements (Section 112-1 in Support Document #34) along
with the application procedures are described in Support Document #34. 
RD’s policy is to send forward the core ecological and environmental
fate data set if the EUP is for an outdoor use .  This EFED review
includes  consideration of listed species.

3.  Emergency Exemptions tc \l3 "3.  Emergency Exemptions  

Section 18 of FIFRA authorizes EPA to allow States and Federal agencies
to apply a pesticide for an unregistered use for a limited time if EPA
determines that emergency conditions exist.   Most requests for
emergency exemptions are made by state lead agricultural agencies,
although the United States Department of Agriculture (USDA), United
States Department of the Interior, and other Federal agencies also have
requested exemptions. The process generally takes place as follows:

Growers in particular regions identify a potential pest control problem
situation that registered pesticides will not alleviate. The growers
contact their state lead agency (usually the state department of
agriculture) and request that the agency apply to EPA for a Section 18
emergency exemption for a particular use. The state agency evaluates the
requests and submits its request to EPA for an emergency exemption if it
believes the request is warranted. The uses are requested for a limited
period of time, no longer than one year (except in the case of
quarantine exemptions, which may be authorized for three years), to
address the emergency situation only. To be responsive to the states and
growers, EPA attempts to make decisions on the requests within 50 days
of receipt of the application.

                        

During this 50-day time period, EPA performs a multi-disciplinary risk
assessment of the requested use, relying largely on data that have
already been reviewed for the pesticide. A dietary risk assessment, an
occupational risk assessment, and an assessment of the emergency are
conducted prior to making a decision. In addition, an ecological risk
assessment, which includes listed species and non-target organisms, is
also conducted.  Within EFED, these assessments are given a high
priority and thus conducted in an expedited basis.  The procedures for
these risk assessments are the same as for Section 3 registrations, but
are limited to the scope of the Section 18 request.  The Agency's
evaluation also includes an assessment of the progress toward
registration for the use in question.

Section 18 actions are screened in RD to determine if there is potential
outdoor impact prior to referral to EFED for a screening-level risk
assessment.  For any action requiring a screening-level assessment, EFED
conducts an assessment, which includes the evaluation of potential
impacts to listed species.  Because of statutory time restraints, these
reviews require rapid turnaround and often consist of EFED simple
refinements of previous assessments for similar uses and rates in the
same geographic area.  If preliminary concerns are determined, refined
assessments are requested from FEAD

Actions that are repeated for a second year for the same use and
geographic area are not referred for review. However, should they return
for a third year they are again sent to EFED for review to determine if
there have been any changes.  

If the emergency appears valid and the risks are acceptable, EPA
approves the emergency exemption request. EPA will deny an exemption
request if the pesticide use may cause unreasonable adverse effects on
health or the environment, or if emergency criteria are not met. As a
matter of course, a state may withdraw an exemption request at any point
in the process.

If a need is immediate, a state agency may issue a “crisis
exemption” under which the State may use the unregistered pesticide
product for up to 15 days or longer if a specific exemption is pending. 
The state notifies EPA of this action prior to issuing the crisis
exemption, and EPA performs a cursory review of the use to ensure there
are no obvious concerns.  If concerns are noted, EPA confers with the
state, and under extreme cases may not allow a crisis to be declared. If
the state follows up the crisis with, or has already submitted, an
emergency exemption request, the use may continue under the crisis
exemption until EPA has made a decision on the request. 

The nature of crisis exemptions precludes pre-use review of potential
ecological effects, including the assessment for potential impacts to
listed species.  However, if the use is to continue beyond the 15-day
limit that is allowed, the actions are referred to EFED for a
screening-level assessment.  If EFED determines there are concerns
regarding listed species, the action follows the process previously
outlined and FEAD conducts a species-specific assessment..

4.  Special Local Need Registrations tc \l3 "4.  Special Local Need
Registrations  

Under Section 24(c) of FIFRA, states may register for use only in that
state an additional use of a federally registered pesticide product or a
new end use product to meet special local needs (SLN) as long as there
is both a demonstrated "special local need," and a tolerance, exemption
from a tolerance, or other clearance under FFDCA.  “Special local
need” means an existing or imminent pest problem within a state for
which the state lead agency, based upon satisfactory supporting
information, has determined that an appropriate federally registered
pesticide product is not sufficiently available.  EPA reviews these
24(c) requests and may approve or disapprove the state action. If the
action is not disapproved, it becomes a permanent registration under
Section 3.   States may not register pesticide products with new active
ingredients under Section 24(c). 

5.  Reregistration Process tc \l3 "5.  Reregistration Process  

Under Section 4 of FIFRA as amended in 1988, EPA is reviewing older
pesticides (those initially registered before November 1, 1984) to
ensure that they meet current scientific and regulatory standards.  This
process, called reregistration, considers the human health and
ecological effects of pesticides and results in decisions to reduce
risks that are of concern.  EPA also is reassessing tolerances
(pesticide residue limits in food) to ensure that they meet the safety
standard established by FQPA.  EPA has integrated reregistration and
tolerance reassessment to most effectively accomplish the goals of both
programs.  

Through the reregistration program, EPA is reviewing the human health
and environmental effects of groups of related pesticide active
ingredients.  When EPA completes the reregistration review and risk
management decision for a pesticide, the Agency generally issues a
Reregistration Eligibility Decision (RED) document. The RED summarizes
the risk assessment conclusions and outlines any risk reduction measures
necessary for the continued registration of the pesticide in the U.S. 

EPA may also issue an Interim Reregistration Eligibility Decision (IRED)
for a pesticide that is undergoing reregistration, requires a
reregistration eligibility decision, and also needs a cumulative
assessment under FQPA. The IRED, issued after EPA completes the
individual pesticide's aggregate risk assessment, presents an interim
decision for the pesticide undergoing reregistration.  It may include
risk reduction measures -- for example, reducing risks to workers or
eliminating uses that the registrant no longer wishes to maintain -- to
gain the benefits of these changes before the final RED can be issued 
following the Agency's consideration of cumulative risks.

To be declared “eligible” for reregistration, pesticides must meet
current scientific and regulatory standards.  The pesticide must have a
substantially complete database and must not cause unreasonable adverse
effects to human health and the environment when used according to
Agency approved labeling directions and precautions. 

In addition, all pesticides with food uses must meet the safety
standard of Section 408 of the FFDCA, as amended by FQPA. FFDCA as
amended by FQPA also requires the reassessment of all existing
tolerances and tolerance exemptions within 10 years, to ensure that they
meet the safety standard of the new law. 

Reducing risks is an important aspect of the reregistration program. 
EPA works with stakeholders including pesticide registrants, growers and
other pesticide users, environmental and public health interest groups,
the States, USDA and other Federal agencies, and others to develop
voluntary measures or regulatory controls needed to effectively reduce
risks of concern.  Almost every RED includes some measures to reduce
human health and/or ecological risks.  The possible ways of achieving
risk reduction are extensive and include measures such as canceling
pesticide products or deleting uses; declaring certain uses ineligible
or not yet eligible (and then proceeding with follow-up action to cancel
the uses or require additional supporting data); phasing out uses;
restricting use of products to certified applicators; limiting the
amount or frequency of use; improving use directions and precautions;
adding more protective clothing and equipment requirements; requiring
special packaging or engineering controls; requiring no-treatment buffer
zones; requiring spray drift labeling; employing ground water, surface
water, or other environmental and ecological safeguards; and other
measures. 

While assessing and mitigating human health risks is a significant
aspect of the reregistration program, assessing and mitigating
ecological risks also is an important part of the reregistration review
process.  In developing REDs and IREDs, the Agency’s internal risk
management process includes an evaluation of each ecological effects
assessment by the ECOR Committee (Ecological Review Group) to ensure
that ecological risks are fully considered and ecological risk
mitigation options are fully vetted. The group consists of staff level
personnel from FEAD, BEAD, RD, EFED, and SRRD.  Issues related to listed
species are discussed by this group and are addressed in the regulatory
document that is prepared.  

Specifically, SRRD  has developed the following procedures to ensure
high quality and consistent management of issues related to listed
species during pesticide reregistration.

History of the Chemical Relative to Listed Species - When a chemical is
scheduled for reregistration, the Chemical Review Manager (CRM) conducts
an analysis of the chemical file to determine if the following
information is available:  incidents involving listed species, earlier
risk assessments indicating potential risks of concern, consultations
with the Services, a Biological Opinion or other indications of concern
for risks to listed species.  A summary of this analysis is shared with
the risk assessors and program managers in EFED and FEAD respectively
and is included in the regulatory history section of the RED for the
chemical.

Summary of the Ecological Risk Assessment - When the ecological risk
assessment is delivered to SRRD, the CRM carefully reviews the
assessment, noting discussion of potential risks to listed species.  The
CRM summarizes the risk conclusions in the risk summary section of the
RED.  Additionally, review managers meet with risk assessors to ensure
they have an accurate understanding of the risk conclusions and have
appropriately summarized them in the RED.

ECOR Review and Recommendations - For any chemical with potential risks
to non-targets, including listed species, the CRM schedules a meeting
with ECOR to ensure key experts in FEAD, EFED, RD, and BEAD are aware of
the risk picture.  Working together they develop a strategy to
appropriately address risks to listed species and can initiate
communications with other stakeholders as needed.



Develop the Risk Management Decision - Through ECOR, the CRM works with
experts in FEAD and EFED to develop the risk management decision and
language that reflects the regulatory decision and rationale sections of
the RED.

Ensure Any Post-RED Changes Still Meet the Risk Management Goals - If,
during a public comment period following publication of the RED,
comments are submitted relating to risks to listed species, the CRM
consults with FEAD and OGC if necessary to determine whether the comment
affects listed species’ risks.

Also, if changes in the regulatory decision are indicated from comments
submitted on any issue, the CRM discusses the comment(s) and alternative
risk management options with FEAD and EFED to ensure that any new
decision still meets the goals of the decision reflected in the RED.

6.  Registration Review tc \l3 "6.  Registration Review  

 FIFRA 3(g) specifies that EPA establish procedural regulations for
conducting registration review and that the goal of the regulations
shall be the Agency review of pesticide registrations on a 15-year
cycle.  An Advance Notice of Proposed Rulemaking was issued in 2000,
which alerted stakeholders that EPA was beginning to develop the
required procedural regulations.  It explained EPA’s preliminary
interpretation of the authorizing legislation, presented EPA’s goals
in implementing the statutory provisions, presented the Agency’s
initial concept of how the registration review program might operate,
identified several issues that needed to be addressed, and invited
public comment.  Since that time, OPP has continued to work on designing
the program and is working on the proposed rule-making.

D.  Addressing Potential Concerns Related to Listed Species tc \l2 "D. 
Addressing Potential Concerns Related to Listed Species 

EPA acknowledges the importance of evaluating the regulatory actions
described earlier for their potential to impact listed species.  This
evaluation may include conducting a screening-level assessment to
determine if there is a potential concern.  If a potential concern is
identified, a species-specific assessment by FEAD may be warranted.

The assessments conducted, either at the screening or the more refined
species-specific level, need to be based on a sound scientific process. 
This process entails using sound scientific  methods, developing
adequate supporting tools such as databases, and conducing adequate peer
review to further strengthen the process.  OPP continually works on
incremental improvements to aspects of the scientific process, which are
consistent with internal Agency policy and evolving Federal
requirements. 

For example, EFED has developed guidance to ensure consistent
consideration and use of information in the open literature for
ecological risk assessments of pesticide effects (Support Document #71).
 This guidance is for use by EFED scientists and steps to implement the
guidance have been initiated.  The database that will be used to search
the open literature will be EPA’S ECOTOX, a comprehensive  tool for
locating chemical toxicity data for aquatic life, terrestrial plants and
wildlife.  Relevant literature for ECOTOX is retrieved using a
comprehensive search strategy designed to locate worldwide aquatic and
terrestrial ecological effects literature.  This database is also
user-friendly, publicly-available, quality-assured and economical.  (See
Section V.B.2.b of this document for further information on the use of
open literature data.)

EPA also recognizes that effective communication and administrative
processes are needed between risk assessment and risk management
divisions if a potential concern related to listed species is
identified.  To help EPA meets its obligations under the ESA, EPA is
enhancing and will continue to improve documentation and communication
of assessment results as they relate to listed species in OPP-related
risk assessment and management decisions.  This will be accomplished by
implementing processes to ensure consistency, timeliness, and
efficiency.  Such documentation will extend beyond the initial screening
level risk assessment efforts and will incorporate a transparent
discussion of any changes to the assessment assumptions, data used for
risk analyses, and the scientific, risk-based, rationale for any
mitigation measures in risk management decisions related to listed and
non-listed species.

IV.  Overview and Organization of the Environmental Fate and Effects
Division tc \l1 "IV.  Overview and Organization of the Environmental
Fate and Effects Division  

EFED performs the following specific functions:

Designs and reviews protocols for environmental data collection.  Works
cooperatively with other government or private entities to gather
environmental measurement data;

Reviews, evaluates, and validates data submitted under FIFRA or provided
from other    sources on the properties and effects of pesticides. 
Although EFED primarily reviews information on the active ingredient,
data on formulations and degradates are also considered when available
to the Agency;

Assesses and characterizes ecological risk from varying pesticide
scenarios in a screening-level assessment, which includes the
consideration of listed species.  The assessment addresses (1) fate and
transport of pesticides in water, soil, and other environmental media;
(2) toxicity to wildlife and vegetation; (3) exposure to non-target
vegetation, aquatic life, birds, and other wildlife; and (4) effects on
listed species.  EFED also conducts a more refined assessment on a
case-by-case basis.

Assesses and characterizes pesticide residues in drinking water used for
human consumption; 

Develops and maintains specific types of databases, such as the
Ecological Incident Information System, and others; and

Develops and advances methods and tools for environmental fate,
ecological risk and    drinking water assessments.

In conjunction with HED, EFED supports OPP’s risk management
divisions, RD and SRRD, in the overall risk assessment of pesticides. 
EFED also provides scientific expertise to other Agency programs and
Federal agencies on the environmental fate and effects of pesticides and
their exposure in various environmental media. In addition, EFED
provides the underlying basis for the FEAD risk assessment (Biological
Evaluation), which evaluates the potential impact on particular listed
species as well as identifies where the risk criteria for listed species
have been exceeded at the screening level. 

EFED is composed of five Environmental Risk Branches (ERB I - V), the
Immediate Office (IO), and the EFED Information Support Branch (EISB).  
The IO includes the Division Director and the Associate Division
Director who manage the division.  Staff in the IO consists of
administrative support personnel, two senior scientists, and a
communications officer who  provide guidance and oversight on key
division projects, implement the communication strategy for the
division, and handle key administrative functions. 

EISB supports the division in the areas of additional administrative
services, filing and document storage, database development and
management, contract management, and tracking chemical actions.  The
EISB consists of administrative support staff, contract specialists,
computer experts, and scientists.

ERB-I through V are responsible for risk assessment functions described
earlier.  These branches are composed of biologists, statisticians,
chemists, environmental engineers and scientists, agronomists, and
hydrologists, predominately with Masters of Science and Doctorate
degrees.

To introduce new employees to the risk assessment processes and to keep
current scientists up-to-date, EFED holds training sessions and
workshops.  New employees are trained by providing them with documents
related to the risk assessment processes, including the Support
Documents provided to the Services.   Formal presentations may also be
held, which include topics such as an overview of OPP and the division
and the ecological risk assessment process.  Presentations on the
assessment process may include providing an overview of the assessment
process, the derivation of risk quotients, and risk assessment
methodology refinements; fate and transport; spray drift; and water
resources.  

For longer tenured employees, workshops and training sessions are held
to keep scientists up-to-date.  For example, EFED held a workshop
recently on aquatic exposure models used in the European Union to
estimate pesticide concentrations in ground and surface water for use in
risk assessments supporting pesticide registration decisions.  The
purpose of the workshop was to provide new information, examine a new
tool that could be used to meet EFED’s modeling needs, and think about
how these models or a similar approach might be applied to meet modeling
needs.  Similar training sessions have included the use of statistics,
computer software training, and other topics.

A.  The Environmental Fate and Effects Division’s Procedures tc \l2
"A.  The Environmental Fate and Effects Division’s Procedures 

EFED scientists review and evaluate studies submitted in support of
registration/reregistration of pesticides to determine if they are
acceptable under FIFRA guidelines. This determination is based on the
design and conduct of the experiment from which the data were derived,
and an evaluation of whether the data submitted fulfill Agency
requirements. In evaluating experimental design, the scientists consider
methods generally recognized by the scientific community, the numbers of
measurements made, and the use of controls in all phases of the
experiment. They evaluate the conduct of each experiment in terms of
whether the study was conducted in conformance with the design, good
laboratory practices were observed, and results were reproducible. The
scientists' review of a study is documented in a Data Evaluation Record
(DER), which provides a summary review of the scientific study.  

A template provides guidance for EPA scientists on how to complete a
DER.  Working with the Pest Management Regulatory Agency (PMRA) of
Canada, EPA has developed 18 individual DER templates for the review of
ecological effects and fate studies.  Scientists use these templates to
review and determine, on a case-by-case basis, whether each study is
scientifically sound and provides sufficient information to satisfy
applicable data requirements

In the DER, a study is categorized as to its usefulness in a risk
assessment.  While different terms have been used over the years to
describe the quality and value of environmental fate and ecological
effects studies, there is consistency in the general meaning of the
classifications and their application.  The three general categories
used for classifying scientific studies are (1) Core or Acceptable, (2)
Supplemental, Upgradable, or Ancillary, and (3) Invalid or Unacceptable.
 (For a more detailed discussion, see Support Document #1.)

Studies are generally evaluated by contractors, who generate DERs under
formats specified by EFED.  The contractor DERs are reviewed by EFED
staff scientists assigned to the pesticide assessment in order to
finalize the data review. The branch Work Assignment Manager (WAM)
oversees the contractor’s performance, and QA/QC procedures are
included in the contractor’s statement of work. The branch WAM
contacts the contractor if there are any problems with the review or if
the review process needs to be changed. 

After DERs for individual studies are developed, EFED scientists
develop the exposure and effects characterizations and the risk
characterization. These assessments are produced by an interdisciplinary
team of scientists and are combined into an integrated science chapter
which describes the potential impact of a pesticide on non-target
organisms and the environment. Science chapters are sent to either SRRD
or RD.  Drinking water exposure assessments are sent to HED for
incorporation into the human health risk assessments.

B.  Data Requirements and Other Data Sources tc \l2 "B.  Data
Requirements and Other Data Sources  

As discussed previously, OPP has the authority, under FIFRA, to require
data in support of the registration of a pesticide product. 
Accordingly, OPP has developed regulations (40 CFR Part 158)  which
specify the types and amount of information that pesticide companies
must routinely submit to EPA to support the registration of pesticide
products. Section 158.290 describes the environmental fate data
requirements, Section 158.490 describes the wildlife and aquatic
organisms data requirements, Section 158.540 describes the plant
protection data requirements, and Section 158.590 describes the
nontarget insect data requirements. 

The data requirements are grouped according to general use pattern(s)
and are listed as either required (R) or conditionally required (CR). In
most cases, the data listed in Part 158 are sufficient to allow EPA to
evaluate a pesticide application. In those cases where the data are not
sufficient, EPA can impose additional data requirements. These data
requirements may be revised from time to time to reflect statutory
changes, policy changes and new technology.  The current data
requirements are identified in Support Document #29. 

Over the course of conducting a risk assessment, the assessors may note
data gaps or identify studies which do not completely satisfy the core
elements for a particular requirement.  In such cases, the risk assessor
will evaluate whether requiring the study (or the repetition of the
study when existing data are not completely satisfactory) would be
likely to materially alter the conclusions of the risk assessment.  This
evaluation considers the nature of the use site for the pesticide, the
types of effects already observed from available acceptable data, and
the present conclusions of the risk assessment.

In the case of registration, risk managers are informed early on of
major data gaps to provide them the opportunity to contact the applicant
and obtain the data. For reregistration, risk managers hold a meeting
with pesticide registrants early in the process to provide them the
opportunity to identify the uses they will support.  This meeting
provides the risk assessor the opportunity to identify any major data
gaps based on an overview of the available data.

If some data are available, then the assessment can be conducted and
uncertainties and assumptions can be identified.  If the assessor
concludes that an additional study will not likely alter the present
conclusions of the risk assessment, they would indicate the data
deficiency to the risk manager and recommend that the study be held in
reserve for reconsideration of its necessity, should future
registrations be considered for the pesticide.  The term “reserve”
is used in its literal sense as meaning something set aside for a
special purpose.  Should a new use scenario in the future be considered
for registration that would likely render the missing information
critical to completion of a new risk assessment, then the data
requirement could be reconsidered by the risk managers.

If a risk assessor concludes that a particular study has the potential
to alter the conclusions of the risk assessment, and the risk manager
believes that such potential creates an uncertainty regarding the
confidence in making a regulatory decision, an interim decision may be
made by the risk manager to grant a registration on the condition of the
completion of an acceptable study.

Other data sources, such as open literature, can also be used in
developing the risk assessment.  Since this information is typically not
collected using the EPA’s test guidelines, it is normally considered
supplemental information.

C.  Processes to Support Sound Science tc \l2 "C.  Processes to Support
Sound Science 

Sound scientific assessments are essential and serve as the foundation
for regulatory decision-making in OPP. In order to advance the quality
and consistency of EPA’s ecological risk assessments, the Agency
developed guidance for improving the ecological assessment process, risk
characterization, and peer review process.  EFED follows the Agency
guidance and has also developed associated and complementary processes
for promoting sound scientific assessments specific to pesticide
regulatory decision-making.

1.  Agency Guidance tc \l3 "1.  Agency Guidance 

a.  Guidelines for Ecological Risk Assessments tc \l4 "a.  Guidelines
for Ecological Risk Assessments 

The  Agency’s Guidelines for Ecological Risk Assessments (Agency
Guidelines, Support Document #7) were issued to advance the quality and
consistency of EPA's ecological risk assessments. As a next step in a
continuing process of ecological risk guidance development, the
guidelines draw from a wide range of source documents including
peer-reviewed issue papers and case studies previously developed by
EPA's Risk Assessment Forum. EFED has been and will be continuing to
advance its assessment processes, using the Agency Guidelines.  This
includes advancements to all three phases of the assessment process,
including problem formulation, analysis, and risk characterization.

b.  Risk Characterization Handbook tc \l4 "b.  Risk Characterization
Handbook 

The Risk Characterization Handbook (Support Document #28) states the
Agency’s risk characterization policy.  It provides a single,
centralized body of risk characterization implementation guidance for
Agency risk assessors and risk managers and calls for a transparent
process and products that are clear, consistent, and reasonable.  

The Handbook includes two parts.  The first is the risk characterization
guide, which describes the goals and principles of risk
characterization, the importance of planning and scoping for a risk
assessment, the essential elements to address in a risk
characterization, the factors considered in decision-making by risk
managers, and the forms the risk characterization takes for different
audiences.  The second part consists of appendices which contain the
Agency’s Risk Characterization Policy and case studies.

c.  Peer Review Handbook tc \l4 "c.  Peer Review Handbook 

The Agency’s Peer Review Handbook (Support Document #30) was issued in
1998 as a single, centralized form of implementation guidance for Agency
staff and manager.  This Handbook builds on an active tradition of peer
review at EPA and reflects the Agency’s long-standing commitment to
peer review.  

EFED has actively participated in the peer review process, which is
discussed in more detail later in this Section (IV.C.3).  The Handbook
has served as an important guide and has helped to ensure that OPP
decisions regarding ecological risk are fully supported by sound and
credible science.

2. Tools to Promote Sound Science tc \l3 "2. Tools to Promote Sound
Science 

EFED uses a variety of tools to ensure that the work performed meets the
necessary level of quality and includes, but is not limited to, the
following elements: Pesticide Assessment Guidelines, Standard Evaluation
Procedures, the development and expansion of scientific databases, and
Technology Teams.

a.  Pesticide Assessment Guidelines tc \l4 "a.  Pesticide Assessment
Guidelines 

EFED has developed Pesticide Assessment Guidelines which provide the
performance requirements and testing and reporting procedures for data
required (Support Document #29) in support of
registration/reregistration of a pesticide.  The guidelines describe
what data are required, test standards that should be considered in
conducting the studies, specific reporting guidance for the tests, and
examples of acceptable protocols, references and other aides to help
with planning and conducting the tests.  They include Subdivision E,
Hazard Evaluation: Wildlife and Aquatic Organisms;  Subdivision J,
Hazard Evaluation: Non-target Plants; Subdivision L, Hazard Evaluation:
Nontarget Insects; and Subdivision N, Chemistry: Environmental Fate
(Support Documents #2, #3, #4, #5, respectively.)

b.  Standard Evaluation Procedures tc \l4 "b.  Standard Evaluation
Procedures 

EFED has developed Standard Evaluation Procedures (SEPs) or guidance
documents (Support Documents #8, #34 - #63) for each type of
environmental test that is generally required to support the
registration/reregistration of pesticides. EFED has also developed SEPs
which describe the Agency's pesticide ecological risk assessment
methods. These documents, which have been designed to ensure
comprehensive and consistent scientific review of data, explain the
scientific procedures used by EFED to evaluate environmental fate and
effects data submitted to  OPP.  Revisions to the SEPs or proposals for
new SEPs are discussed and developed within the six EFED Technology
Teams, followed by review and approval by the Science Policy Panel. 
After internal approval by the Science Policy Panel and division
management, the SEPs are reviewed by an external science peer review
group, such as the Scientific Advisory Panel.  (The Technology Teams,
Science Policy Panel and Scientific Advisory Panel are discussed in more
detail later in this Section [IV.C.2.d, IV.C.3.c, and IV.C.4,
respectively)

c.  Databases tc \l4 "c.  Databases 

EFED continues to develop, advance, and expand its databases and
information systems to support a sound scientific process.  These
include the Ecotoxicity Database, Ecological Incident Information
System, and Environmental Fate Database along with databases that
address ground and surface water.  In addition, EFED also uses EPA’S
ECOTOX, a comprehensive  tool for locating chemical toxicity data for
aquatic life, terrestrial plants and wildlife.  (See Section V.B.2.b.
for further discussion.) 

OPP’s Ecotoxicity Database - Over the last 30 years, pesticide
manufacturers have submitted thousands of ecotoxicity studies to support
the registration or reregistration of their pesticide products.
Ecotoxicity studies measure the effects of chemicals on fish, wildlife,
plants, and other wild organisms.   EFED reviewed these studies
according to criteria outlined in the Standard Evaluation Procedure
Manuals and testing methods accepted by the scientific community. After
reviewing these studies, EFED scientists  determined if they were
acceptable for use in the regulatory process.  These data are used,
along with consideration of other publically available effects data, in
establishing the effects endpoints for screening-level risk assessments.
(See Section V.B.2.b.)



In 1991, EFED began electronically summarizing acceptable studies and
has now entered over 15,000 summary records for about 680 pesticide
active ingredients into a computerized database called the Pesticide
Ecotoxicity Database.  These summary records include endpoint
measurements such as the LD50 (the amount or dose of a chemical which
kills 50% of the exposed animals) and the NOEL or No Observed Effect
Level (the highest concentration of a chemical in a toxicity test that
has no significant adverse effect on the exposed population of test
animals).  Although most of the toxicity information in this database
was compiled from studies conducted by commercial laboratories, the
database also contains acceptable studies, which meet the Agency’s
testing requirements, conducted by EPA; U.S. Department of Agriculture;
and the U.S. Geological Survey (the former U.S. Fish and Wildlife
Service).  Further information is also available in Support Document
#32.  

Ecological Incident Information System - In 1992, the Agency created a
database called The Ecological Incident Information System (EIIS) to
store information extracted from incident reports.  (Documentation is
provided in Support Document #22.)  The two primary sources of incident
reports are pesticide registrants and government agencies.  Under
Section 6(a)(2) of FIFRA, pesticide manufacturers are required to report
to EPA any information related to known adverse effects to the
environment caused by their registered pesticides.

The second major source of information is investigative reports which
are voluntarily submitted to the Agency from state and other federal
agencies that oversee agriculture, wildlife, natural resources, and
environmental quality. Diagnostic reports are also obtained from the
National Wildlife Health Institute (U.S. Geological Survey), the
Patuxent Wildlife Research Center (U.S. Geological Survey), the
Southwest Wildlife Cooperative Disease Study, and state wildlife
forensic laboratories. In addition, information is also extracted from
accounts of ecological incidents reported in newspapers and reliable
internet sources. 

Information included in EIIS includes the date and location of the
incident, the type of adverse effects observed, the number of animals
affected by species, and the identity of the pesticide or pesticides to
which the incident was attributed.  When available, further details may
be entered about the rate and method of pesticide applications, legality
of the pesticide use, weather conditions, and results of any chemical
residue and cholinesterase activity analyses conducted during the
incident investigation.  Often insufficient information is available to
confirm the cause of incidents with certainty.  For each pesticide
identified in the incident report, an EPA employee assigns a certainty
index value to reflect the level of certainty that the specific
pesticide caused the observed effects.  The certainty index is set to
highly probable, probable, possible, unlikely, or unrelated based on
results of residue analysis and other evidence of cause.  The certainty
index is always reported along with the other incident data and should
be carefully considered when interpreting incidents.  

Environmental Fate Database - OPP collects and reviews a variety of
environmental fate studies submitted by pesticide manufacturers in
support of the registration and reregistration review of pesticide
products.  After reviewing the data in these studies, OPP scientists
summarize the information in DERs, REDs, and other reports.

In 2000, OPP initiated the development of a pesticide environmental
fate database which will allow the user to search and view the data,
query the fate database, and print reports that are found in these
summary reports.  OPP plans to complete the initial version of this
database by the end of 2004.

d.  Technology Teams tc \l4 "d.  Technology Teams 

EFED has six Technology Teams (Tech Teams), which are organized by
scientific disciplines and meet on a regular basis to promote sound
science and work on technical issues within the Division. They include
the Fate and Transport Team, Aquatic Biology Team, Plant Biology Team,
Terrestrial Exposure Assessment Team, and Water Quality and Exposure
Assessment Team.  The purpose of these teams is to:

Facilitate scientific consistency within disciplines, which includes
consistency in data review, use of data in assessments, application of
statistics and modeling, and use of assessment processes and tools;

Provide a forum to keep up with scientific advances and to facilitate
interaction between scientists with similar background or common
scientific interest; 

Resolution of technical issues, resulting in new scientific guidance and
procedures; and

Provide a resource of information and guidance for scientific issues and
new ideas.

Once a technical issue has been resolved, a policy is in place which
outlines the basic steps for reviewing and approving new science
guidance and procedures (Support Document #64).  The length of time for
implementation will vary, depending on the issues raised and whether
external peer review is needed. However, provisions have been made to
implement guidance and procedures which need an expedited review and
approval.  It should be noted that special project teams are also
required to use the same procedures.

3. Internal Peer Review Mechanisms tc \l3 "3. Internal Peer Review
Mechanisms 

a.  Data Evaluation Records tc \l4 "a.  Data Evaluation Records 

All DERs are peer reviewed internally at the branch level by another
EFED scientist with the appropriate expertise. After the branch-level
peer reviewer approves and finalizes the DER, copies are sent to the
EFED Tracking Team who forwards it to the appropriate risk management
division.

b.  Risk Assessments and Risk Characterizations tc \l4 "b.  Risk
Assessments and Risk Characterizations 

All risk assessments and risk characterizations are reviewed within a
task team consisting of scientists from different disciplines. After the
team reviews these documents, they are peer reviewed within the branch
or in another EFED branch by a scientist with appropriate expertise. 

Following branch-level review, divisional peer review is conducted by
the Risk Assessment and Risk Characterization Review Panel (Review
Panel) which consists of interdisciplinary scientists who peer review
all major risk assessments and risk characterizations for new chemicals
and for reregistration actions. This Panel is an important internal peer
review mechanism and is composed of senior scientists in the division. 
In addition, FEAD scientists participate and provide technical comments
on the assessment process in general and as it relates to listed
species.  After panel members have reviewed a specific risk assessment,
they meet with scientists, provide feedback, and ask questions
concerning the assessment.

c.  Science Policy Panel tc \l4 "c.  Science Policy Panel 

The Science Policy Panel is comprised of five experienced, highly
qualified experts in the environmental and ecological risk assessment of
pesticides.  They are responsible for providing assistance to Tech Teams
in policy problem formulation, review of proposed science policies for
consistency and quality, and in developing implementation and
communication plans for new policies.  They are also responsible for
participating in the EFED budget process and making recommendations
regarding new projects and establishing priorities.

4.  External Peer Review and Scientific Advisory Panel tc \l3 "4. 
External Peer Review and Scientific Advisory Panel 

All significant new science guidance and procedures as well as tools and
methodologies  are reviewed by the FIFRA Scientific Advisory Panel
(SAP), EPA’s peer review body for current scientific issues related to
pesticides.  It is comprised of nationally and internationally
recognized scientific experts in toxicology, pathology, environmental
biology, and related sciences; and members are appointed by the
Administrator.  

For example, the FIFRA SAP has peer reviewed the new tools and
methodologies OPP has been developing in its initiative to refine the
ecological assessment process for pesticides.  This initiative, which
began in 1997, was in response to recommendations from a meeting with
the SAP in 1996 and built upon previous efforts in the Division.
Throughout the development of this initiative, OPP has returned to the
SAP several times to seek comments and recommendations on the progress
being made.  In some cases, EFED has sought guidance from the SAP on
problematic issues and questions before proceeding further.  Input from
the SAP  early in the development of tools and methods is critical to
their successful implementation in the risk assessment process.

V.  Overview of OPP’s Screening-Level Ecological Risk Assessment
Process for Aquatic

       Life, Wildlife, and Plants tc \l1 "V.  Overview of OPP’s
Screening-Level Ecological Risk Assessment Process for Aquatic      
Life, Wildlife, and Plants   

This section provides an overview of the screening-level assessment
process to evaluate the potential impact of pesticides on non-target
organisms.  (Section VI provides an overview of the species-specific
assessment.)  As previously mentioned, this process is consistent with
the Agency’s Guidelines for Ecological Risk Assessment (Support
Document #7).   Although this section reviews the general assessment
process for screening-level assessments, this assessment process may, on
a case-by-case basis, incorporate additional methods, models and lines
of evidence that EPA finds technically appropriate for specific risk
management objectives. 

The majority of screening-level assessments are conducted in EFED for
conventional pesticides.  However, some screening-level assessments are
also conducted in AD and BPPD for non-conventional pesticides.  The
ecological assessments conducted by AD and the microbial assessments
conducted by BPPD are largely based on the process described in this
section. However, BPPD also conducts assessments for biochemicals,
which, because of their unique nature, do not typically follow the same
procedures and are more qualitative in nature.  The assessment processes
conducted by AD and BPPD are described in Appendices A and B,
respectively.

A.  Problem Formulation tc \l2 "A.  Problem Formulation 

Before the risk assessment process begins, risk assessors and risk
managers discuss (1) the potential value of conducting a risk
assessment, (2) goals for ecological resources, (3) range of management
options, (4) objectives of the risk assessment, (5) the focus, scope and
timing of the assessment, and (5) resource availability. The
characteristics of an ecological risk assessment are directly determined
by agreements reached by risk managers and risk assessors during early
planning meetings.  In addition to discussions between risk assessors
and risk managers, information provided by the pesticide registrants is
also taken into consideration when developing the problem formulation. 
It should be noted that the problem formulation will document, when
necessary, any aspects of the analysis that extend beyond the initial
screening level risk assessment efforts.  The problem formulation will
allow for an analysis of any changes in risk estimates based on
different assessment assumptions, including those that may be related to
proposed mitigation options, and data used for risk analyses.

1.  Defining the Regulatory Action tc \l3 "1.  Defining the Regulatory
Action 

Prior to initiation of the risk assessment process, risk managers
communicate the nature of the regulatory action to the risk assessors. 
For risk assessment activities supporting REDs, these communications are
initiated with personnel from SRRD.  For regulatory actions involving
new pesticide active ingredients or new uses of active ingredients with
existing registrations (FIFRA Section 3 actions), emergency exemptions
(FIFRA Section 18 actions), and special local needs uses (FIFRA Section
24c actions), the regulatory communications are initiated with personnel
from RD.   

During this problem formulation phase, risk assessors and risk managers
consider the following questions:

What is the regulatory basis for the requested action under FIFRA?  How
does this action affect the temporal and geographic scope of the impact
area of the risk assessment?

What are the management goals and regulatory issues?  How will the risk
assessment clarify decisions concerning risk management options?

Are there any policy considerations that everyone should be aware of? 

What precedents are set by similar risk assessments and previous
decisions?

2. The Nature of the Chemical Stressor Considered in the Risk Assessment
tc \l3 "2. The Nature of the Chemical Stressor Considered in the Risk
Assessment 

The Agency routinely incorporates measures of exposure and effects for
the pesticide active ingredient in the risk assessment process for all
regulatory decisions.  Additionally, EPA examines available formulated
product information, environmental fate data, and toxicological data to
determine the need to expand beyond the focus on the active ingredient
to consider pesticide formulations, inert ingredients, or degradates of
the active ingredient in a particular risk assessment to support
registration of a specific pesticide product.  Available formulated
product information, environmental fate data, and toxicological data may
come from a number of sources.  These include section 6(a)(2) data, open
literature data retrieved through ECOTOX (see Section V.B.2.b), and
direct submissions in support of registration.  The methods for
incorporating environmental fate and effects data for formulations and
active ingredient degradates into the risk assessment processes are
described in Section V.B. 1 and 2, in which exposure and effects are
discussed.  

The Agency is currently developing procedures for assessing toxicity and
risks associated with inert ingredients and surfactants in formulations
(See Support Document #24) and will perform either qualitative or
quantitative assessments of potential risk associated with these
chemicals.  The decision to perform either type of assessment is based
on available information on the chemical characteristics of the inert
ingredient and any information on the inert ingredient’s toxicological
characteristics.  Information on an inert ingredient’s toxicological
characteristics may include available ecological effects information
from the literature, or information on closely related chemical
analogues and quantitative structure-activity relationships.  Use of
structural analogy or structure activity models is consistent with
techniques employed in other Agency programs (e.g., the approach used by
OPPT in evaluating new chemicals in commerce through the
Premanufacturing Notification process).  This information is used to
determine if inert ingredients can be classified as (1) generally
recognized as safe, (2) available data are insufficient to confirm
little or no toxicity and would require additional study, or (3) there
is sufficient toxicological and exposure concern to warrant a
quantitative risk assessment similar to those conducted for active
ingredients. 

It is important to note that existing and vetted quantitative
structure-activity relationships have focused on industrial chemicals,
the types of compounds commonly found as inert ingredients and
surfactants in pesticide formulations.  Establishing these relationships
has been facilitated by the non-specific modes of toxic action of these
compounds and are typically based on simple correlations between their
acute potency to aquatic organisms as measured by lethality (e.g., LC50
values) and basic physical/chemical properties of the compounds. 
Application of quantitative structure activity relationships developed
for industrial chemicals to predict effects for pesticide active
ingredients is not scientifically defensible due to their different, and
highly specific, modes of toxic action for these active ingredients when
compared to industrial, organic chemicals.

The Agency does not routinely include, in its screening risk
assessments, an evaluation of mixtures of active ingredients, either
those mixtures of multiple active ingredients in product formulations or
those in the applicator’s tank.  In the case of the product
formulations of active ingredients, each active ingredient is subject to
an individual risk assessment for regulatory decision regarding the
active ingredient on a particular use site.  If effects data are
available for a formulated product, it is documented in the risk
assessment and the quantitative or qualitative use of such formulation
information follows procedures outlined in the discussion on exposure
and effects characterization.

In accordance with risk assessment guidance, the Agency documents the
scope of the chemical stressors considered in the risk assessment, the
rationale for their consideration, the methods used to evaluate the
attendant risks, and their contribution to the overall conclusions of
the risk assessment.

3.  Pesticide Use Characterization tc \l3 "3.  Pesticide Use
Characterization 

For each regulatory action, product labeling provides information on the
proposed and/or existing uses of the pesticide product.  The pesticide
labeling is the legal document that provides the user with instructions
for use, use restrictions, and hazard statements  (see Support Documents
#67 and #68).  Risk assessors use the information on the product
labeling to define the nature of the pesticide use in the field.  Use
factors on the labeling are important for determining input parameters
for exposure models and the magnitude of exposure to non-target
organisms, including geographic locations most likely to be exposed.
Labeling information crucial to ecological assessments include:

Type of formulation, such as bait, granule, wettable powder,
emulsifiable concentrate, etc.;

Product purity, which is the proportion of that product that is the
pesticide active ingredient;

Proposed and/or existing application rates;

Treated crop(s) and, if specified, target pest(s);

Geographic limitations of use, if any;

Application methods, such as aerial, ground, foliar, soil surface, soil
incorporated, etc.;

Application timing, such as season and time of day;

Frequency of application, application intervals, and maximum number of
applications per season; and

Hazard advisory statements: protective measure for wildlife/aquatic
habitats, groundwater, etc.

In addition to the information on the label, scientists consult with
BEAD and the registrant for information on the following topics:  

Nature of the target pests,

Geographical distribution of the pests, crop, and market of the
pesticide,

Temporal pattern of the pesticide’s use, and 

Any unique aspects of the use of the pesticide under field conditions.

The characterization of pesticide use allows the risk assessors and risk
managers to focus the risk assessment on specific use patterns that are
representative of a larger variety of use patterns.  Such groupings may
consider the types of agricultural scenarios, the methods for pesticide
application, and commonality of applications rates and timing.  In this
way, modeling and assessment resources can be concentrated on scenarios
that reasonably represent the highest exposures among a suite of use
scenarios.

4.  Identification of Assessment Endpoints tc \l3 "4.  Identification
of Assessment Endpoints  

The Agency Guidelines define assessment endpoints as “explicit
expressions of the actual environmental value that is to be protected”
which are “operationally defined by an ecological entity and its
attributes” (Support Document #7). The ecological entity can be a
species, a functional group of species, a community, an ecosystem, or
another entity of importance or concern.  An attribute is the
characteristic of the entity that is important to protect and is
potentially at risk.  

The selection of clearly defined assessment endpoints is important
because they provide direction and boundaries in the risk assessment for
addressing risk management issues of concern. Each assessment endpoint
needs one or more “measures of effect,” which are changes in the
attributes of an assessment endpoint itself or changes in a surrogate
entity or attribute in response to exposure to a pesticide.

a.  Direct Effects tc \l4 "a.  Direct Effects 

The typical assessment endpoints for screening-level pesticide
ecological risk assessments are reduced survival and reproductive
impairment for both aquatic and terrestrial animal species from both
direct acute and direct chronic exposures. These assessment endpoints,
while measured at the individual level, provide insight about risks at
higher levels of biological organization (e.g., populations).  Hallam
and Lassiter (1994) assert that toxicants do not affect populations or
communities except through the impact on the individuals comprising the
population or community and the demographics of  birth, growth, and
death that govern population dynamics. Similarly, Tanner (1978)
indicates that the number of individuals within a population change
(intrinsic rate of increase) primarily because of births (fecundity) and
deaths (survival) and secondarily from migration in and out of a
specific area.  Investigations by Hakoyama et al. (2000) concerning risk
factors of wildlife population extinctions suggest that toxicant effects
on individual survivorship have important implications for both
population rates of increase and habitat carrying capacity.  If effects
on the survival and reproduction of individuals are limited, it is
assumed that risks at the population level from such effects will be of
minor consequence. However, as the risk of reductions in survival and/or
reproduction rates increase, the greater the potential risk to
populations.

For terrestrial plants, the screening assessments are concerned with
perpetuation of populations of non-target species (crops and non-crop
plant species).  Existing testing requirements have the capacity to
evaluate emergence of seedlings as well as vegetative vigor. Although it
is recognized that the endpoints of seedling emergence and vegetative
vigor may not address all terrestrial plant life cycle components, it is
assumed that impacts at emergence and in the active growth stages have
the potential to impact individual competitive ability and reproductive
success.

For aquatic plants, the assessment is concerned with the maintenance and
growth of standing crop or biomass.  Measurement endpoints for this
assessment focus on algal growth rates and biomass measurements as well
as similar measurements for vascular plants.

b.  Indirect Effects for Listed Species tc \l4 "b.  Indirect Effects for
Listed Species 

Screening-level assessments of indirect effects for listed species are
discussed in Sections B.2.c and C.4  of this chapter.  Species-specific
assessments for indirect effects on listed species are developed, when
required, after the screening-level evaluation is completed. (See
Section VI for further discussion.)

c.  Effects on Listed Species Critical Habitat tc \l4 "c.  Effects on
Listed Species Critical Habitat 

Screening-level assessments of effects upon critical habitat for listed
species are discussed in Sections B.2.d and C.5 of this chapter. 
Species-specific assessments for critical habitat of listed species are
developed, when required, after the screening-level evaluation is
completed.  (See Chapter VI for further discussion.)

5.  Measures of Effects and Exposure: The Use of Surrogate Organisms tc
\l3 "5.  Measures of Effects and Exposure: The Use of Surrogate
Organisms 

Rarely are toxicity data available for the species identified in the
risk assessment endpoints.  In the majority of cases, the
screening-level risk assessment process relies on a suite of toxicity
studies performed on a limited number of organisms in the following
broad groupings:

Birds (mallard duck and bobwhite quail) used as surrogate for
terrestrial-phase amphibians and reptiles,

Mammals (laboratory rat),

Freshwater fish (bluegill sunfish, rainbow trout, and fathead minnow)
used as a surrogate for aquatic phase amphibians,

Freshwater invertebrates (Daphnia magna),

Estuarine/marine fish (sheepshead minnow), 

Estuarine/marine invertebrates (Crassostrea virginica and Mysidopsis
bahia),

Terrestrial plants (corn, soybean, carrot (radish or sugar beet), oat
(wheat or ryegrass), tomato, onion, cabbage (cauliflower or brussels
sprout), lettuce, cucumber), and

Algae and aquatic plants (Lemna gibba, Skeletonema costatum, Anabaena
flos-aquae, Selenastrum capricornutum, Clorell vulgaris, Scenedesmus
subspicatus)

Within each of these very broad taxonomic groups, an acute and a chronic
endpoint are selected from the available test data.  The selection is
made from the most sensitive species tested within that organism group. 
If additional toxicity data for more species of organisms in a
particular group are available, the selection need not be limited to the
species listed above, but may be expanded to include data for other
species/studies that meet the data quality classification of
“supplemental.”  (See Support Document #1 for discussion of the data
classification scheme.)  Available scientific information from alternate
sources (e.g. searches conducted using the ECOTOX database described in
Section V.B.2.b.1) is also examined for species within a taxonomic group
for which other taxa are typically used as surrogates. For example, fish
data are commonly used to evaluate impacts to amphibians.  But, if
toxicity data are available in the open literature on amphibians, these
data may be used instead of the data on the surrogate species.  In
situations where such additional data are available, decisions are made
regarding the quality and utility of such information in the risk
assessment (e.g., a review of the validity and reliability of study
protocols), which is consistent with the Agency’s risk assessment
guidance.  The extent to which such additional data are either employed
or rejected is described through a transparent, concise discussion. 
Regardless of the extent of data beyond the regulation-required set of
toxicity studies, the risk assessment relies on selection of endpoints
from the most sensitive species tested in acceptable studies. 

Exposures estimated in the screening-level risk assessment for
non-target organisms are likewise not specific to a given species. 
Aquatic organism (plant and animals) exposures are based on a set of
standardized water body assumptions (water body size, watershed size,
proximity to field, etc.) that result in high-end estimates of exposure
(see Section V.B.1.b).  Estimates of exposure for terrestrial birds and
mammals assume that animals are in the treatment area, and exposure
estimates involve grouping taxa based on food preferences (e.g.,
obligate insectivores, herbivores, granivores) and generic weight
classes.  Exposure for terrestrial plants considers surface runoff from
treated fields as well as direct application via pesticide spray drift.

6.  Identification of Data Gaps tc \l3 "6.  Identification of Data Gaps 

When a data package is received for a registration of a new active
ingredient or a new use, the submissions are reviewed to ensure that the
environmental fate and ecological effects data sets are complete for the
proposed pesticide use.  For actions in which a database for the active
ingredient is already available (i.e., reregistration, new uses of
existing active ingredients, Section 18s, etc.), the risk assessor
reviews the adequacy of existing and new submissions and previous
assessments.  In either case, whenever possible, data gaps are noted
early on in the risk assessment process and communicated to the risk
manager as discussed in Section IV.B.  Data gaps are addressed as a
source of uncertainty in the risk assessment conclusions, and the risk
assessment discusses the potential for additional data to affect the
risk assessment conclusions.  In the absence of data, adverse effects
may be assumed to occur until a study is submitted to indicate
otherwise.

Once data gaps in the ecological effects and environmental fate
databases are identified, the risk assessment team must determine
whether it is possible to perform the risk assessment.  A
screening-level ecological risk assessment is possible when the data
submitted on ecological effects and environmental fate of the pesticide
are scientifically valid and complete based on the Agency’s review
criteria in the Standard Evaluation Procedures (see Support Documents
#35 - #63).   Studies for effects are classified in one of three
categories:  core, supplemental, and invalid.   Core data are from
studies found to be scientifically valid and conducted consistent with
Agency testing guidelines.  Supplemental data are from studies found to
be scientifically valid but do not follow all requirements set forth in
Agency testing guidelines.  Invalid data are from scientifically unsound
studies.  Similar classifications of data are set forth for
environmental fate studies.  

In some instances, a core study may not be available for a particular
data requirement listed in 40 CFR 158. In this case, the risk assessment
team may consider other sources of information to address the data gap
(e.g., submitted studies considered to be supplemental and data from
other sources not submitted as part of fulfillment of 40 CFR 158).  If
supplemental or non-guideline study data are available to address the
type of information described by the associated guideline, then it may
be used in the risk assessment after its use is carefully considered. 
Professional judgment is used by the risk assessment team to determine
the utility of the available supplemental data for the proposed risk
assessment.  This latter evaluation may include reference to data
quality objectives for specific types of studies, the degree to which
adequate documentation is available to evaluate the technical merit of
the data, and whether the data are applicable to the assessment
endpoints established for the risk assessment.  The Agency’s risk
assessment guidelines instruct risk assessors to clearly and concisely
document the evaluation of all data considered in the risk assessment. 
Even if supplemental or non-guideline data are used to address a data
gap in the risk assessment, the risk assessment team will still note the
gaps in the guideline study requirements and provide the risk manager
with a determination of the potential impact of those gaps upon the
confidence of the risk assessment.

There may be other instances where there is a lack of scientifically
valid data (i.e., neither core or supplemental data are available).  In
this situation, certain aspects of the risk assessment may not be
performed.  In such situations, discussions with the risk manager ensue
to determine whether these data gaps will seriously limit regulatory
decision-making.  In the absence of data needed to make the required
findings under FIFRA, EPA cannot register or reregister a pesticide.

B.   Analysis Phase tc \l2 "B.   Analysis Phase 

1.  Exposure Characterization tc \l3 "1.  Exposure Characterization 

In most cases, an exposure characterization conducted in support of a
regulatory decision of a pesticide provides a quantitative analysis of
the critical environmental fate and transport properties of the
pesticide active ingredient.  However, there are situations where
formulations are of demonstrated higher toxicity than the active
ingredient alone, or where degradates occur in significant amounts or
are of significant toxicological concern.  In such situations, exposure
characterizations would include a quantitative or qualitative analysis
of the risk implications of organism exposure to these degradates or
formulations in addition to the active ingredient.  The Agency’s risk
assessment guidance instructs risk assessors to clearly and concisely
describe the nature of the stressors evaluated in the risk assessment. 
This includes documentation of the potential significance of degradates
and formulations in the risk assessment of pesticides.  Section
V.B.1.a., which is found below, and materials in Support Document #78,
relating to HED’s Metabolism Assessment Review Committee (Section
V.B.2.), describe the process for including degradates in the risk
assessment.  Sections V.B.1.b.(2) and V.B.1.c.(2) discuss specific
exposure methods  for the quantitative consideration of pesticide
formulations in the risk assessment.

The quantitative expressions of the fate and transport properties, along
with the information related to the use of the pesticide active
ingredient and the physical, chemical, and biological conditions of the
use sites are used to estimate the potential exposure of plants,
wildlife, and aquatic life to pesticide residues in environmental media.
 This characterization includes information on how often, how long, and
the amount of  pesticide active ingredient and its degradates of concern
to which an organism may be exposed.  The exposure characterization is
based on environmental fate and transport data, modeling, and monitoring
information.

In order to quantitatively predict the fate and transport of a pesticide
once it is introduced into the environment, OPP scientists review
laboratory and field studies that measure how  pesticide active
ingredients interact with soils, air, sunlight, surface water, and
ground water.  These studies provide information concerning:

The degradation of the pesticide active ingredient (how fast and by what
process it is degraded in the environment) and how persistent the
pesticide active ingredient is in the environment;

The breakdown products that result from the degradation processes; 

The mobility of a pesticide active ingredient or its degradates or
metabolites and how it will move from the application site; these
studies predict the potential of the pesticide to volatilize into the
atmosphere, move into ground or surface waters, or bind to the soil; and

How much of a pesticide active ingredient and its degradates or
metabolites will accumulate in the environment.

a.  Fate and Transport Data Requirements and Study Evaluation tc \l4 "a.
 Fate and Transport Data Requirements and Study Evaluation  

The Agency regulations found in 40 CFR 158.290 (Support Document #29)
describe the types and amount of data the Agency commonly uses for
assessing the environmental fate of an active ingredient. These data are
generated from controlled laboratory and field studies, which are
conducted under approved Guidelines and Good Laboratory Practices.  They
are used to determine the persistence, mobility, and bioconcentration
potential of a pesticide and its major degradates in the environment.  

The types of data required may vary depending on where the pesticide is
used.  Some of these studies, such as hydrolysis, photolysis, aquatic
and soil metabolism, and terrestrial dissipation, are routinely
conducted for all outdoor use pesticides.  Others are conditionally
required and are triggered by use or application patterns and basic
product chemistry data.    

Controlled environmental fate and transport laboratory studies are used
to determine the persistence, mobility, and bioconcentration potential
of a pesticide active ingredient and its major degradates.  Persistence
studies assess what happens to a pesticide active when it interacts with
water, soil, air, and sunlight.  Mobility studies attempt to predict the
potential of the active ingredient to volatilize into the atmosphere,
move into ground or surface waters, or bind to soil.   Bioconcentration
studies evaluate the potential of an active ingredient to partition to
aquatic biota and the degree to which bioconcentration can be reversed
should external exposure to the active ingredient or degradates be
reduced or eliminated.  These studies are designed to help characterize
how a pesticide active ingredient dissipates once it is released into
the environment and to identify the major degradates that may result
from these processes. 

Degradation studies include hydrolysis, photodegradation in water,
photodegradation in air, and photodegradation on soil.  The hydrolysis
study determines the potential of the pesticide active ingredient to
degrade from the influence of water alone.  Photodegradation studies 
determine the potential of the active ingredient to degrade in water,
soil, or air when exposed to sunlight.  During these studies, data are
also collected concerning the identity, formation and persistence of
major degradates.

Metabolism studies include aerobic soil metabolism, anaerobic soil
metabolism, anaerobic aquatic metabolism, and aerobic aquatic
metabolism.  The soil microbial metabolism  studies determine the
persistence of the pesticide active ingredient when it interacts with
soil microorganisms under aerobic and anaerobic conditions.  The aquatic
metabolism studies produce similar data, but are generated by active
ingredient interaction with microorganisms in a water/sediment system. 
These studies also identify the significant degradates that result from
biological degradation.

Mobility studies, which include leaching, adsorption/desorption, and
volatility, provide information on the mode of transport and eventual
destination of the pesticide active ingredient in the environment. 
Scientists can predict the degree of pesticide mobility in soil from
data generated from leaching and adsorption/desorption studies.

Bioconcentration studies in aquatic organisms are used to estimate the
potential of a pesticide active ingredient, under controlled laboratory
conditions, to partition to the organisms from respiratory and dermal
exposures.  These studies also provide information on the degree to
which bioconcentration of a pesticide or degradate can be reversed
should pesticide levels in the surrounding aquatic environment be
reduced.

Field studies which identify the environmental dissipation processes,
assess the transformation, transport, and fate of pesticide active
ingredient under actual use conditions with typically applied pesticide
product at representative field sites.  These studies characterize the
relative importance of each route of dissipation of the pesticide active
ingredient and its major degradates.  Data generated from field
dissipation studies can provide more realistic estimates (albeit limited
in time and space) of the persistence and transport of an active
ingredient and its degradates when the pesticide product is applied
under actual use conditions.

Guidance for reviewing environmental fate and transport studies is
provided in Subdivision N Guidelines and the associated Standard
Evaluation Procedures (Support Documents #5, # 41 - #44, #60 - #62.).
However, OPP may also review sources of data other than those conducted
according to the Subdivision N Guidelines, such as non-guideline studies
submitted by the pesticide registrant and data published in the
scientific literature.  It is important to note that the manner in which
additional non-guideline data are incorporated into a risk assessment is
established on a case-by-case basis.  The risk assessment team uses
professional judgment in evaluating such aspects as: 

The data quality objectives of the study, 

Availability of documentation sufficient for evaluating the technical
merit of the methods and results analysis, and 

General applicability of the results as compared to the exposure
scenarios that are considered important in the risk assessment.  

The Agency recognizes the importance of using the best available science
in characterizing environmental exposure.  Non-guideline data may be
used to address data gaps in the assessment, even to the extent of
providing quantitative values for dissipation pathway inputs for
exposure modeling.  These data may even be useful for addressing fate
issues that are not specifically identified in the existing guideline
studies.  The risk assessment team must clearly and concisely document
the environmental fate information considered in the risk assessment. 
Though data from non-guideline studies may be considered supplemental
information in a risk assessment, they cannot be used to satisfy
guideline requirements to support registration.

In addition to assessing the environmental fate of active ingredients,
the Agency requirements indicate that the formation of degradates be
monitored in the fate studies.  This is often accomplished through the
use of radio-labeled compound to ensure that detection limits are
sufficiently low to allow for detailed tracking of the production of
degradates.   Degradates formed at greater than or equal to 10% of the
applied radioactivity in the environmental fate studies are considered
significant (i.e., major degradates) and must be identified (see Support
Document #5).  The 10% criterion is a general guideline, meaning that
degradates approaching concentrations of 10% of the applied
radioactivity are usually identified as well.  In addition, degradates
of known toxicological or ecotoxicological concern must be quantified
and identified even when present at less than 10% of the applied
radioactivity.  

In order to identify degradates of toxicological concern, environmental
fate scientists engage in discussions with human health reviewers in HED
and ecotoxicology reviewers in EFED.  (Support Document #78 provides
additional information on the process used by the Agency to identify
degradates of concern.)  In accordance with Agency risk assessment
guidance, the risk assessment team must clearly and concisely document
the rationale of including or excluding degradates from consideration in
the risk assessment.

Once the individual studies are reviewed and determined to be
appropriate for inclusion in the risk assessment, OPP relies on the
results of these studies to provide the quantitative fate and transport
inputs for ecological exposure modeling.  Selection of these input
values are specific to the exposure model being used. ( Guidance for the
selection process can be found in Support Documents #9, #17, and #18.) 
The following sections (B.1.b,c,and d) discuss exposure modeling methods
available to OPP for screening-level risk assessments.

b.  Aquatic Organism Exposure Modeling tc \l3 "b.  Aquatic Organism
Exposure Modeling 

(1).  General Approach tc \l5 "(1).  General Approach 

For aquatic organisms, such as plants, fish, aquatic-phase amphibians,
and invertebrates, OPP generally uses computer simulation models to
estimate exposure to a pesticide active ingredient.   These models
calculate estimated environmental concentrations (EECs) in surface water
using laboratory data that describe how fast the pesticide breaks down
to other chemicals and how it moves in the environment.  Section V.B.1.b
(2) describes the Agency’s approach for exposure modeling in
situations where available information suggests that ecological risks
from formulated products should be considered.

In aquatic organism modeling, a tiered system of modeling is used to
efficiently allocate resources to assessment efforts of varying
complexities and potential risks.  The intent of the lower tiers is to
provide a screening approach to estimate the concentration of a
pesticide in water from sites that are highly vulnerable to runoff or
leaching.  OPP is confident that when a pesticide is not predicted to
cause adverse effects on the environment using EECs generated from
screening- level tiers, that the possibility of harming the environment
is low.  The assessment moves to a more refined one that is based on
conditions more reflective of actual use site conditions, when Levels of
Concern (LOCs), discussed later in this section, are exceeded using EECs
based on generic assumptions (non-use site specific).

The first screening model employed is a generic one that is not specific
to the particular use-site.  This model, GENEEC2 (GENeric Estimated
Environmental Concentration), is used to screen chemicals to determine
the ones which potentially pose sufficient risk to warrant more detailed
or refined modeling.  The GENEEC2 calculates high-end estimates of
surface water concentrations of pesticides in a generic farm pond.  The
Agency considers this scenario a high-end estimate for the following
reasons: 

The input value for the application rate and number of applications is
the labeled maximum;

The entire watershed is assumed to be cropped and treated with the
pesticide, and the watershed area is high relative to the volume of the
water body;

No buffer is assumed between the pond and the treated field;

Runoff is assumed to be from a 6-inch rainfall over a 24-hour period;
and

The geographic location of use is regarded as representative of high-end
potential for pesticide runoff and is not necessarily representative of
runoff conditions for the labeled use. 

GENEEC2 provides a rapid screen to separate the low risk pesticides from
those that need more refined assessments. The model estimates high level
exposure values of pesticides in surface water using the following
inputs:

  

Basic chemical characteristics, 

Pesticide label use and application information, 

Adsorption of the pesticide to soil or sediment, 

Direct deposition of spray drift into the water body, and 

Degradation of the pesticide in soil before runoff and within the water
body.  

GENEEC2 is a single-event model, based on a single, large
rainfall/runoff event occurring on a 10-hectare field that removes a
large quantity of pesticide at one time from the field to a pond that
has a 20,000-liter water volume and is 2-meter deep. (See the GENEEC2
User's Manual and GENEEC2 Model Description for more information, which
may be obtained from the following url:
www.epa.gov/oppefed1/models/water/index.htm.)

If the LOC for risk to non-target species is not exceeded using GENEEC2
EECs, OPP is confident that there is no risk of concern.  If the LOC is
exceeded using GENEEC2 EECs, a small possibility exists, albeit
unlikely, that an extreme exposure could exceed toxicity thresholds
established in the effects characterization.  However, the risk
assessment team cannot discount the possibility that GENEEC2 model
assumptions leading to such high-end exposure predictions may not be
realistic for the labeled use of the pesticide.  In those instances
where exposure levels exceed the levels associated with the toxic
threshold, a more realistic exposure characterization is established
using a more comprehensive model (PRZM-3 and EXAMS II) and runoff
conditions more reflective of labeled use sites.

 The PRZM-3 and EXAMS II model provides more realistic, use-site
specific EEC values by refining the model inputs for pesticide transport
and transformation down through the crop root and unsaturated zone, and
runoff and spray drift loading in the farm pond.

   

PRZM-3 is a process or "simulation" model that calculates what happens
to a pesticide in treated fields on a day-to-day basis. It considers
factors such as rainfall and plant transpiration of water, as well as
how and when the pesticide is applied. It has two major components: 
hydrology and chemical transport. 

The hydrologic component for calculating runoff and erosion of soil is
based on the USDA Natural Resource Conservation Service curve number
technique and the Universal Soil Loss Equation.  Evapotranspiration of
water from the root zone of the soil profile is estimated either
directly from pan evaporation data or is based on an empirical formula
(Penman 1948). Total evapotranspiration of water includes evaporation
from crop interception, evaporation from soil, and transpiration by the
crop. Water movement is simulated by the use of generalized soil
parameters, including field capacity, wilting point, and saturation
water content.  To reflect the high-end of the distribution of pesticide
exposures across varying sites, OPP selects hydrologic scenarios  based
on the targeting of model outputs.

The chemical transport component of PRZM-3 simulates pesticide
application on the soil or on the plant foliage. Dissolved, adsorbed,
and vapor-phase concentrations in the soil are estimated by
simultaneously considering the processes of pesticide uptake by plants,
surface runoff, erosion, decay, volatilization, foliar wash-off, and
sorption.  

Each PRZM modeling scenario represents a unique combination of climatic
conditions, crop-specific management practices, soil-specific
properties, site-specific hydrology, and pesticide-specific application
and dissipation processes. Each PRZM simulation is conducted using up to
36 years of rainfall data to cover year-to-year variability in runoff. 
PRZM-3 allows the user to consider pulse loads and predict peak events. 
Daily edge-of-field loadings of pesticides dissolved in runoff waters
and sorbed to sediment, as predicted by PRZM, are discharged into a
standard water body ("standard pond" for ecological assessments)
simulated by the EXAMS model.

EXAMS II is also a process model that simulates the processes that
occur in the water body rather than on the agricultural field. EXAMS II
takes the runoff and spray drift loadings generated by PRZM and
estimates the concentration in the pond on a day-to-day basis.  It
accounts for volatilization, sorption, hydrolysis, biodegradation, and
photolysis of the pesticide in the aquatic environment.  Since EXAMS is
a steady-state model, the water bodies are modeled as having constant
volume.  Multiple-year pesticide concentrations in the water column are
calculated from the simulations as the annual daily peak, maximum annual
96-hour average, maximum annual 21-day average, maximum annual 60-day
average, and annual average. The 1 in 10 year maximum values for each
averaging period are used to calculate risk quotients. An input
parameters selection manual, which provides guidance in selecting input
values for using these models, can be found in Support Document #9.

For surface water modeling, PRZM/EXAMS assumes 5% and 1% spray drift for
aerially and ground applied pesticides, respectively.  The 5% assumption
is based on a linear interpolation of spray drift data presented in
Akesson (1990).  (See Section V.C.4.10 for a comparison of these assumed
drift levels with other drift modeling outputs.)  The risk
characterization section of the risk assessment includes a discussion of
the potential impact of alternative drift estimates on the overall
confidence of the risk assessment conclusions.

For pesticides that are currently on the market, water monitoring data
may be available   from EPA databases, U.S. Geological Survey, National
Water-Quality Assessment Program, industry, states, and universities. 
These data are evaluated on a case-by-case basis to determine the
likelihood, extent, and nature of pesticide concentration in water under
current use practices and actual field conditions.  The risk assessment
team considers such study aspects as the points and frequency of sample
collection, the analyte suite, and detection limits when determining how
such data will be incorporated into the risk assessment. When reliable
surface water monitoring data are available, EPA uses it to help
characterize the levels of pesticide that are being detected in the
environment.  Monitoring, though, does not necessarily target pesticide
use areas or the time of year when pesticide concentrations may be at
their peak, and for this reason may not   provide a reliable estimate of
acute exposure.   If monitoring data shows higher confirmed detections
than estimated by modeling, the higher monitoring values may be used in
the risk assessment, and a re-evaluation of the model input parameters
may be initiated to explore the impact of selected input values on the
model output.  

More detailed descriptions of these aquatic models can be found on
EPA’s Web site at the following url:
www.epa.gov/oppefed1/models/water/index.htm

(2).  Special Aquatic Exposure Methods for Pesticide Formulations tc \l5
"2).  Special Aquatic Exposure Methods for Pesticide Formulations 

In situations where available toxicity data indicate that a pesticide
formulation for registration in the United States may be more toxic to
aquatic biota than indicated by active ingredient effects testing, it
may be necessary to consider aquatic exposure to the formulation. 
Exposure modeling in these instances is limited to situations where
direct instantaneous introduction of the formulation to surface waters
occurs by direct application to those waters or by incidental
application as a result of drift.  The screening-level assessment model
for such direct or incidental application is based on the standard farm
pond scenario used for EXAMS modeling.

The limitation on the quantitative exposure modeling for formulations
is based on the expectation that the varying physical-chemical
properties of individual components of pesticide formulations will
result in progressively different formulation constituents in
environmental media over time.  As the proportions of formulation
components in environmental media differ from the proportions in the
tested formulation, the assumption that environmental residues are
toxicologically equivalent to tested formulations cannot be supported
beyond the time period immediately following product application.  This
assumption is especially important in the case of runoff from treated
areas to surface waters.  In this case, partitioning and degradation
properties for each formulation component suggest that the final
proportion of the residues of these components in the receiving surface
waters would not represent what was introduced and what was tested in an
aquatic organism toxicity study using the formulated product.

While EPA does not require the same data on end-use products as the EU,
the operation of the adverse effects reporting provisions in FIFRA
section 6(a)(2) and implementing regulations assure that EPA has the
same database for performing its ecological risk assessments as the EU. 
The Agency’s methods for considering formulated product exposure in
the screening-level aquatic organism risk assessment is functionally
equivalent to the approaches developed by the European Union for
evaluating pesticide formulation risks (see Support Document #80 - EU
Council Directive 91/414/EEC).

c.  Terrestrial Organism Exposure Modeling tc \l4 "c.  Terrestrial
Organism Exposure Modeling 

(1).  General Approach tc \l5 "(1).  General Approach 

Terrestrial wildlife exposure estimates are typically calculated for
birds and mammals, emphasizing a dietary exposure route for uptake of
pesticide active ingredients.  These exposures are considered as
surrogates for terrestrial-phase amphibians as well as reptiles.  For
exposure to terrestrial organisms, OPP primarily looks at the residues
of pesticides on food items and assumes that organisms are exposed to a
single pesticide residue in a given exposure scenario.  Two approaches
are used for estimating exposure to terrestrial wildlife, which are
dependent on the application method: (1) spray applications and (2)
granular, bait, and treated seed applications.  Section V.B.1.c.2
describes the Agency’s approach for exposure modeling in situations
where available information suggests that formulation risks should be
considered.  It should be noted that, although the screening-level
terrestrial wildlife risk assessment focuses, in large part on dietary
exposure the Agency does consider the relative importance of other
routes of exposure in situations where data indicate that pesticide
exposures through routes other than dietary may be potentially
significant contributors to wildlife risk.  (Such data could be
identified, for example, through the ECOTOX database.  See Section
VI.B.2.b.1.)  OPP, in its risk characterization (see section VI.C),
discusses the impact of consideration of other routes of exposure that
have been identified as potentially important on the degree of certainty
associated with screening-level risk assessment conclusions.

For spray applications, estimation of pesticide concentrations in
wildlife food items   focuses on quantifying possible dietary ingestion
of residues on vegetative matter and insects.  The residue estimates are
based on a nomogram that relates food item residues to pesticide
application rate.  The nomogram is based on an EPA database called UTAB
(Uptake, Translocation, Accumulation, and Biotransformation), a
compilation of actual measured pesticide residue values on plants
(Nellessen and Fletcher 1992), and work from Fletcher et al. (1994). 
(See Support Document #15).  

In avian risk assessments, dietary residues are compared with toxicity
endpoints based on dietary concentration (e.g., LC50 for acute effects).
 Conversely residues may be first converted to an ingested whole body
dose. In the case of small mammals, for example, no dietary-based
toxicity information is available so residues are converted to an
ingested dose and compared to single oral-dose toxicity endpoints (i.e.,
LD50).  The conversion of dietary residues to oral dose and then
comparison with LD50 data is also performed for an avian risk assesment
when the single oral dose route appears to provide a more suitable
measure of effects than the dietary toxicity study.  In either case, the
first tier of the nomogram uses the maximum predicted residues. 
Subsequent refinements may consider mean residues.  However, maximum
residue values are used in the screening-level assessments for listed
species.  For mammals, the residue concentration is converted to daily
oral dose based on fractions of body weight consumed daily as estimated
from mammalian allometric relationships in EPA’s Wildlife Exposure
Factors Handbook (Support Document #33).  In all screening-level
assessments, the organisms are assumed to consume 100% of their diet as
one food type, thereby eliminating the need at the screening level for
evaluating mixtures of dietary items.

For granular, bait, and treated seed applications, estimation of
loadings of pesticide per unit area are calculated.  This approach,
which is intended to represent exposure via multiple routes and not just
direct ingestion, considers observed effects in field studies and
relates them to the pesticide applied to surface area. The label rate of
application for the active ingredient is the basis for the exposure
term.  Using the following assumptions, the amount of pesticide per
square foot is calculated:

In-furrow applications assume a typical value of 1% granules, bait, or
seed remain unincorporated;

Incorporated banded treatments assume that 15% of granules, bait, seeds
are unincorporated.  This is an average of measurements ranging from 6
to 40 %; and  

Broadcast treatment without incorporation assumes 100% of granules,
bait, seeds are unincorporated.

(2).  Special Terrestrial Exposure Methods for Pesticide Formulations tc
\l5 "2).  Special Terrestrial Exposure Methods for Pesticide
Formulations 

In situations where available toxicity data indicate that a pesticide
formulation for registration in the United States may be more toxic to
terrestrial wildlife than indicated by active ingredient effects
testing, it may be necessary to consider exposure to the formulation. 
Exposure modeling in these instances is limited to dietary exposure to
residues for a time period immediately following pesticide product
application.

The limitation on the quantitative exposure modeling for formulations is
based on the expectation that the varying physical-chemical properties
of individual components of pesticide formulations will result in
progressively different formulation constituents in environmental media
over time.  Because the proportions of formulation components in
environmental media differ from the proportions in the tested
formulation, the assumption that environmental residues are
toxicologically equivalent to tested formulations cannot be supported
beyond the time period immediately following product application. 

The Agency’s methods for considering formulated product exposure in
the screening-level terrestrial organism risk assessment follows
approaches developed by the European Union for evaluating pesticide
formulation risks (see Support Document #80 - EU Council Directive
91/414/EEC).

d. Non-Target Plant Exposure Modeling tc \l4 "d. Non-Target Plant
Exposure Modeling 

As discussed previously in the aquatic organism exposure section,
exposure for non-target aquatic plants is assessed in a manner
consistent with exposure for other aquatic organisms.

Terrestrial and semi-aquatic plant exposure characterization employs
runoff and spray drift scenarios contained in OPP’s Terrplant model
(Support Document #18).  Exposure calculations are based on a
pesticide’s water solubility and the amount of pesticide present on
the soil surface within the first inch of depth.  For dry areas, the
loading of pesticide active ingredient from runoff to an adjacent
non-target area is assumed to occur from one acre of treatment to one
acre of non-target area; for semi-aquatic (wetland) areas, runoff is
considered to occur from a larger source area with active ingredient
loading originating from 10 acres of treated area to a single acre of
non-target wetland.  Default spray drift assumptions are 1% for ground
applications and 5% for aerial, airblast, forced air, and chemigation
applications.  Drift is not considered for formulations of herbicides
that are not spray-applied (e.g., granules); however, runoff is still
considered and expressed on a percent of applied mass basis.  A
discussion of the uncertainties associated with the drift assumptions is
included in section VI.C.6 .b.10 and are included in the risk
characterizations for screening-level risk assessments.

2.  Effects Characterization tc \l3 "2.  Effects Characterization 

In screening-level ecological risk assessments,  effects
characterization describes the types of effects a pesticide can produce
in an organism and how those effects change with varying pesticide
exposure levels.  This characterization is based on an effects profile
that describes the available effects (toxicity) information for various
plants and animals and an interpretation of available incidents
information and effects monitoring data.  Environmental fate data,
monitoring data, and computer models are used to estimate the exposure
of non-target animals and plants to pesticide residues in the
environment.

40 CFR Parts 158.490, 158.540, and 158.590 specify the types and amounts
of data that the Agency needs to determine the risks of a  pesticide to
wildlife, aquatic organisms, and plants.  The types of data needed can
vary depending on how and where the pesticide is used.  A list of the
studies that the Agency may require in support of the registration or
approval of certain pesticides is provided in Support Document #29.  

In these tests, organisms are exposed to different amounts of pesticide
active ingredient (and under certain conditions formulated product and
degradates) and their responses to these varying concentrations are
measured.  Study endpoints are used to estimate the toxicity or hazard
of a pesticide.  (See Support Documents #45, #47-49, #52-53, #57, and
#63 for toxicity categories.)  The toxicity testing scheme is tiered,
such that results from a lower level study are used to determine
potential harmful effects to non-target organisms and whether further
testing is required.  Testing can progress from basic laboratory tests
at the lowest level to applied field tests at the highest level.

For screening risk assessments, the following toxicity endpoints are
used as inputs to the Risk Quotient (RQ) method for expressing risk (see
Section V. C.1) :

Aquatic Animals	

Acute assessment 	 		Lowest tested EC50 or LC50 for freshwater fish and
invertebrates and estuarine/marine fish and invertebrates acute toxicity
tests.

Chronic assessment 			Lowest NOEC for freshwater fish and invertebrates
and estuarine/marine fish and invertebrates early life-stage or full
life-cycle tests.

Terrestrial Animals	

Acute avian assessment		Lowest LD50 (single oral dose) and  LC50
(subacute dietary).

Chronic avian assessment 		Lowest NOEC for 21-week avian reproduction
test.

Acute mammalian assessment 	Lowest LD50 from single oral dose test.

Chronic mammalian assessment 	Lowest NOEC for two-generation
reproduction test.

Plants				

Terrestrial non-endangered 		Lowest EC25 values from both seedling
emergence and vegetative vigor for both monocots and dicots.

Aquatic vascular and algae		Lowest EC50 for both vascular and algae.

Terrestrial endangered 		Lowest EC5 or NOEC for both seedling emergence
and vegetative vigor for both monocots and dicots.

While the above toxicity endpoints are routinely used to calculate
screening-level risk assessment RQs, they do not represent a limitation
on the types of toxicity endpoints that may be considered in the risk
assessment.  Over the course of evaluation of available toxicity data
(see Section V.B.2 for a discussion of OPP’s use of ECOTOX database
for effects data searches), the risk assessment team may encounter other
effects data that provide: (1) additional information on existing
toxicity endpoints commonly used in the screening risk assessment, (2)
insight on endpoints not routinely considered for RQ calculation, and/or
(3) effects data on specific additional taxonomic groups (e.g.,
amphibian and freshwater mussel tests).  Professional judgment is used
and documented  by the risk assessment team to determine whether and how
available data on other toxicological endpoints are included in the risk
assessment.  This evaluation may include (1) reference to data quality
objectives for specific types of studies, (2) the degree to which
adequate documentation is available to evaluate the technical merit of
the data, and (3) whether the data are applicable to the assessment
endpoints established for the risk assessment.  To decide if data are
applicable to assessment endpoints, the risk assessment team uses
professional judgment and available lines of evidence to determine if
the toxicological endpoints can be linked to assessment endpoints in a
reasonable and plausible manner. 

As stated earlier in this section, the Agency routinely conducts
screening-level risk assessments on an active ingredient basis.  The
only routine exception to this is for terrestrial plant effects
analysis, where toxicity studies are conducted on the formulated
product.   Consequently, the majority of toxicity data received by the
Agency relates to the active ingredient.  However, Agency regulations 
have provisions for the request of additional data on formulated
products.  40 CFR 158.75 allows the Agency to request additional data if
routinely required data are not sufficient to evaluate the potential of
a pesticide product to cause unreasonable adverse effects on man or the
environment.  In addition., 40 CFR 158.202 indicates that acute aquatic
animal toxicity testing may be required if any of the following
conditions are met:

The end-use product is applied directly to water when used as directed;

Active ingredient LC50/EC50 values are equal to or less than the maximum
expected environmental concentration or the estimated environmental
concentration in aquatic systems when the product is used as directed;
or

An ingredient in the end-use product is expected to enhance the toxicity
of the active ingredient or is toxic itself to aquatic organisms.

Support Document #78 presents the Agency’s process for the
identification of degradates of potential toxicological concern.  This
information, in conjunction with any available toxicity data and data
regarding the extent to which degradates are produced in laboratory and
field environmental fate studies, will be considered by the Agency to
determine the need for incorporating active ingredient degradates in a
risk assessment. This evaluation, which  is conducted by the Metabolism
Assessment Review Committee, may be based upon information relating to
(1) biologically reactive chemical moieties on both the active and
degradates, (2) past experience with close chemical analogues, (3)
consultation with Agency human health toxicologists, and (4)  publically
available literature.   If degradates are considered by the Agency to be
of toxicological significance as determined by the process outlined in
Support Document # 78, the Agency evaluates the available information to
determine if quantitative or qualitative consideration of degradate
risks is warranted.  The rationale supporting such decisions are
documented in the risk assessment document.  To be consistent  with
Agency risk assessment guidance,  risk assessors must clearly and
concisely describe this evaluation in the risk assessment.

Formulated product effects data are evaluated and included in the risk
assessment when available.  (See Section V.A.2 for sources of such
information).  Acute mammalian effects testing for formulated products
is commonly submitted to the Agency.  In addition, effects testing for
formulations is required for registrations in other nations (EU
Directive 91/414/EEC).  The Agency provisions for submission of effects
data under 40 CFR 159.165(b) suggest that formulation effects
information conducted for other nations would be submitted to the Agency
when it indicates that the formulation may be more toxic than the active
ingredient.  In addition, searches of the publicly available literature
may identify additional effects data for formulations.

Before formulated product effects data can be considered quantitatively
in the risk assessment, it must be evaluated for its applicability to
formulations under consideration for registration.  This evaluation
includes a comparison of the confidential statement of formulation for
the product  proposed for registration with any available information on
the constituents of the tested formulation.  If the comparison suggests
that the tested and proposed registration formulations are similar, the
test data are used quantitatively in the risk assessment process. 
However, if a similarity is not supported by the available formulation
information, the toxicity data on formulated products is documented, and
the risk characterization qualitatively discusses the potential
implications the formulated toxicity may have on the confidence of the
risk assessment conclusions.

a.  Registrant-Submitted Studies for Direct Effects of Pesticides tc \l4
"a.  Registrant-Submitted Studies for Direct Effects of Pesticides 

Support Documents #45 - #57 and #63 list the universe of toxicity
studies commonly submitted by pesticide registrants in support of
registration proposals.  40 CFR Section 158 describes the criteria that
serve as the basis for the requirements for each type of study.  The
Agency has determined, that under most situations, these effects data
are sufficient for risk assessment purposes. 

b.  Open Literature Studies for Direct Effects of Pesticides tc \l4 "b. 
Open Literature Studies for Direct Effects of Pesticides 

In addition to registrant-submitted data, the Agency also consults
publicly available  literature for additional toxicity information to be
used in screening risk assessments, such as studies on additional taxa,
toxicity endpoints, routes of exposure, or test materials.  (See Section
V.B.2.) 

To ensure consistent consideration and use of information in the open
literature for ecological risk assessments, OPP has developed guidance
for its scientists (Support Document #71) and steps to implement the
guidance have been initiated.      

(1).  ECOTOX tc \l5 "(1).  ECOTOX 	

OPP uses the ECOTOX (ECOTOXicology) database as a search engine to
identify open literature studies that may potentially be used in
ecological risk assessments

(http://www.epa.gov/ecotox).   The ECOTOX database was selected because
it is a user-friendly, publicly-available, quality-assured,
comprehensive tool for locating open literature chemical toxicity data
for aquatic life, terrestrial plants, and wildlife.  Relevant literature
for ECOTOX is retrieved using a comprehensive search strategy designed
to locate worldwide aquatic and terrestrial ecological effects
literature.  This strategy is expected to capture the data from research
that evaluates species and/or toxic effects, which fall outside the
standard battery of required ecotoxicity tests.

The ECOTOX database is developed and maintained by EPA’s National
Health and Environmental Effects Research Laboratory, Mid-Continent
Ecology Division (MED) in Duluth, Minnesota.  ECOTOX includes unique
toxicity data for aquatic life, terrestrial plants, and terrestrial
wildlife and contains information on lethal, sublethal and residue
effects.  With regard to terrestrial animals, ECOTOX’s primary focus
is wildlife species, but the database does include some information on
domestic species. Sources routinely used for ECOTOX searches are
AGRICOLA, Cambridge Scientific Abstracts (CSA), BIOSIS and CAB
Abstracts, Current Contents, ScienceDirect, and MED library journal
holdings.  Relevant sources are also identified from benchmark documents
and review papers, and online ecotoxicology databases such as the U.S.
Geological Survey’s  “Wildlife and Contaminants Online” website
http://www.pwrc.usgs.gov/contaminants-online/ and the Canadian Wildlife
Service’s “Reptile and Amphibian Toxicology Literature” website
http://www.cws-scf.ec.gc.ca/nwrc-cnrf/ratl/index_e.cfm.

The ECOTOX database can issue two types of reports.   The aquatic
organism report includes toxic effects data on all aquatic species
including plants and animals and freshwater and saltwater species, while
the terrestrial organism report contains toxicity data for terrestrial
animals and terrestrial plants.  

The high level of quality assurance of the ECOTOX database makes it an
important  primary source for consistently searching open literature
data.  Extensive documentation for this database, ranging from Standard
Operating Procedures, Coding Guidelines, Chemical Verification, and
various procedures, are described in Support Documents #72 - #77.

Quality assurance procedures begin with literature acquisition and
cataloging and continue through the chemical and species verification,
the literature review process, data entry, and data retrieval. The
ECOTOX literature is encoded by trained document abstractors. An
intensive training period, a well-documented manual, and close
interaction with the data coordinator help to ensure a high level of
accuracy and consistency in the review process. Ten percent of the
publications are independently reviewed by two different reviewers.
These reviews are compared, and differences (if any) are documented,
discussed, and resolved by the data coordinator.  

This procedure provides a consistent attempt at finding data. Since
there is a lag time of three months between literature acquisition and
data availability in ECOTOX, OPP may request MED to search their
reference files for any unreviewed studies on a chemical of concern.  In
addition, OPP will work with MED to identify citations and papers in
their holdings that were not encoded in ECOTOX, including studies
conducted on chemical mixtures, formulations, inert ingredients and
surfactants, and survey and incident data. 

(2).  OPP Strategy for Conducting Literature Searches tc \l5 "(2).  OPP
Strategy for Conducting Literature Searches 

OPP is refining a search strategy that it will follow for finding and
filtering pesticide data in ECOTOX and is establishing guidance that
describes how to evaluate the data output from ECOTOX.  After
identifying pesticide toxicity data in ECOTOX that may be useful in a
pesticide risk assessment, copies of the journal articles and study
reports will be retrieved so that the risk assessor may more closely
critique the study.  MED holds paper copies of all studies cited in the
ECOTOX database and copies of applicable papers can be provided to OPP
upon request.  

This guidance, which will help maintain consistency concerning when and
how data from open literature can be used, will help the risk assessor
determine if an open literature study can be used in a pesticide risk
assessment.  Development of this guidance is being coordinated with
other OPP quality assurance guidance.  In addition, EPA science policy
documents will be used as a base in developing the guidance
(http://www.epa.gov/osp/spc/2polprog.htm and 
http://www.epa.gov/oei/qualityguidelines), and the guidance will be
similar to previous work by OPP (U.S. Environmental Protection Agency,
2003), Superfund (http://www.epa.gov/ecotox/ecossl/), Office of Water
(U.S. Environmental Protection Agency, 2002a), and EVISTRA (U.S.
Environmental Protection Agency, 2002b).

  	

In accordance with established risk assessment guidance, the Agency will
identify in the risk assessment (1) the effects data from the literature
that were considered in the risk assessment, (2) the basis for decisions
on the manner in which such data were incorporated in the risk
assessment, and (3) the rationale for not including data obtained from
the literature.							

c.  Open Literature Studies for Indirect Effects of Pesticides tc \l4
"c.  Open Literature Studies for Indirect Effects of Pesticides 

To obtain best available information for interpreting the potential for
indirect effects at the screening level, the Agency will utilize
“species profiles”, when available, prepared by the Services for
other Federal action agencies (e.g., EPA’s Office of Water).  These
summaries, or profiles, are considered current best available
information concerning species’ life history, ecology, population
demographics, etc., and will be provided to the Agency by the Services. 
The Agency anticipates that the Services will provide the Agency with
similar summary information for listed species not covered by existing
“species profiles.” 

d.  Open Literature Studies for Critical Habitat Evaluations tc \l4 "d. 
Open Literature Studies for Critical Habitat Evaluations 

To obtain best available information for interpreting the potential for
critical habitat evaluations at the screening level the Agency may
utilize “critical habitat profiles”, when available, prepared by the
Services.  These summaries, or profiles, are considered current best
available information concerning principle constituent elements for
specific species and will be provided to the Agency by the Services.
Critical habitat profiles provide the Agency with an identification of
the principle constituent elements or equivalent (e.g., lists of
biological resource requirements for the listed species associated with
the critical habitat).

C.   Risk Characterization tc \l2 "C.   Risk Characterization 

Risk characterization is the integration of effects and exposure
characterization to determine the ecological risk from the use of the
pesticide and the likelihood of effects on aquatic life, wildlife, and
plants based on varying pesticide-use scenarios.  The Agency’s policy
and guidance (Support Document #28) requires that risk characterizations
be prepared in a manner that is clear, transparent, reasonable, and
consistent with other risk characterizations of similar scope.  

1.  Integration of Exposure and Effects Data - The Risk Quotient for
Direct 

Effects tc \l3 "1.  Integration of Exposure and Effects Data - The Risk
Quotient for Direct Effects 

Risk characterization integrates the results of exposure and toxicity
data to evaluate the likelihood of adverse ecological effects on
non-target species.  For most chemicals, the effects characterization is
based on a deterministic approach using one point on a
concentration-response curve (e.g., LC50).  In this approach, OPP uses
the risk quotient (RQ) method to compare exposure over toxicity. 
Estimated environmental concentrations (EECs) based on maximum
application rates are divided by acute and chronic toxicity values.
(Equations are provided in Support Document #8.)  

2.   Levels of Concern for Direct Effects - The Policy Tool for
Interpreting Risk Quotients for Direct Effects tc \l3 "2.   Levels of
Concern for Direct Effects - The Policy Tool for Interpreting Risk
Quotients for Direct Effects 

After risk quotients are calculated, they are compared to the Agency’s
LOCs.  These LOCs are the Agency’s interpretative policy and are used
to analyze potential risk to non-target organisms and the need to
consider regulatory action.  These criteria are used to indicate when a
pesticide use as directed on the label has the potential to cause
adverse effects on non-target organisms.  A discussion of the
developmental history is provided in support document # 70. LOCs
currently address the following risk presumption categories:

Acute - Potential for acute risk to non-target organisms which may
warrant regulatory action in addition to restricted use classification
(acute RQ > 0.5 for aquatic animals, mammals, birds);

Acute Restricted Use - Potential for acute risk to non-target organisms,
but may be mitigated through restricted use classification (acute RQ >
0.1 for aquatic animals or 0.2 for mammals and birds);

Acute Endangered Species - Endangered species may be potentially
affected by use (acute RQ > 0.05 for aquatic animals or 0.1 for mammals
and birds);

Chronic Risk - Potential for chronic risk may warrant regulatory action,
endangered species may potentially be affected through chronic exposure
(chronic RQ > 1 for all animals); 

Non-endangered Plant Risk - RQ >1; and 

Endangered Plant Risk - Potential for effects in endangered plants
(RQ>1).

It should be noted that both acute endangered species and chronic risk
LOCs are considered in the screening-level risk assessment of pesticide
risks to listed species.  Endangered species acute LOCs are a fraction
of the non-endangered species LOCs or, in the case of endangered plants,
RQs are derived using lower toxicity endpoints than non-endangered
plants.  Therefore, concerns regarding listed species within a taxonomic
group are triggered in exposure situations where restricted use or acute
risk LOCs are triggered for the same taxonomic group.  The Agency risk
assessment also includes, both in the risk characterization and the
endangered species sections, an evaluation of the potential probability
of individual effects for exposures that may occur at the established
endangered species LOC.  This probability is calculated using the
established dose/response relationship and the median lethal dose
estimate for the study used to establish the toxicity endpoint for the
endangered taxa.

As discussed earlier in this document, the Agency is not limited to a
base set of surrogate toxicity information in establishing risk
assessment conclusions.  The Agency also considers toxicity data on
non-standard test species (e.g., amphibian data) when available.  (See
Section V.B.2.b.on searches for publically available effects
information.)  To the extent that such data meet data quality
requirements, it is used to interpret the relevance of risk assessment
LOCs in the context of other tested taxa.

3.  Comparison of Field and Laboratory Data for Direct Effects tc \l3
"3.  Comparison of Field and Laboratory Data for Direct Effects 

Given the general widespread nature of pesticide uses and the
variability in the physical, chemical, and biological conditions
associated with pesticide use sites, validation of the results of the
existing screening risk assessment process would be impractical. 
However, OPP does consider data on exposure and effects collected under
field conditions to make determinations on the predictive utility of the
screening assessment.

After the 1992 Ecological, Fate, and Effects Task Force review of the
testing requirements for environmental fate and ecological effects, the
Agency decided to not require avian and aquatic guidelines field
testing, except in unusual circumstances (Support Document #25). 
However, when field studies along with incident data reports and
compliance monitoring studies are available, they are used to help
elucidate the potential sources and magnitude of uncertainties when
extrapolating from effects predictions based on laboratory toxicity data
to effects occurrence in the field.  As pointed out in the Agency’s
Guidelines for Ecological Risk Assessment (Support Document #7),
developing solid  relationships between cause and observed field effects
adds to the certainty of the assessment. The criteria presented in these
guidelines adopted from Fox (1991) and similar to other criteria
reviewed by Fox (U.S. Department of Health, Education, and Welfare,
1964; Hill, 1965; and Susser, 1986a and 1986b) stressed the importance
of the strength of association between the causative agent and the
observed effect.

OPP routinely receives information on the field dissipation of
pesticides under actual use conditions.  These data provide the Agency
with information on the persistence of the parent compound and the rate
of production of degradates.  Incorporation of the results of field
dissipation data into the quantitative exposure modeling is problematic
because of  the nature of the model input requirements.  However,
overall rates and routes of pesticide decline as predicted by the fate
models can be examined and compared with the results of the field
dissipation models to determine the degree to which the risk assessment
fate modeling may overstate exposure.

In addition to field dissipation measurements, scientists often consider
available data on environmental media monitoring for pesticides.  For
example, the results of the screening environmental models are compared
with monitoring data for surface waters.  As previously mentioned,
though, there are practical limitations to surface water monitoring
efforts.  For example, non-targeted routine monitoring programs, such as
the U.S. Geological Survey’s National Water-Quality Assessment
Program, are more useful for tracking trends than they are for
establishing true peak concentrations.  However, comparison of the
Agency modeling results with such monitoring programs can provide some
insight into the degree to which modeling results reflect realistic
conditions in the field.

As discussed for surface water monitoring, field effects data are
limited in the ability to account for the myriad combinations of
physical, chemical, and biological variables that may affect organism
response to pesticides in the environment.  Consequently, field studies
or incident reports cannot conclusively validate screening risk
assessment predictions, but they can allow inferences on the
reasonableness of the assessment predictions.

Incident information can add lines of evidence to provide context to
the risk predictions from the screening level assessment.  Sometimes
this reporting provides limited information for an ecological assessment
because most incidents are not reported, and those that are reported,
often do not have enough information to assess cause and effect. 
Generally, it is assumed that the application was from normal use and
was applied within the rates allowed on the labeling, unless otherwise
indicated. On occasion, the use rates are reported in incident
investigations, but actual documentation with scientific rigor is rare.
Therefore, incident reports often provide limited information about the
correlation between use rates and effect levels.  However, consistent
with components of the criteria described by Fox (1991), the greater the
number of wildlife mortality incidents following application of a
specific pesticide for a specific use, and the greater the number of
individuals involved, the higher the confidence in the strength of the
association.  The more confidence in the association between incident
and pesticide exposure, the more useful the information when evaluating
risk conclusions derived from laboratory-based screening assessment
methods. The Agency maintains a database, which is described in Section
IV.C.2.c, of incident information to support risk assessment. 

4.  Indirect Effects Characterization for Listed Species tc \l3 "4. 
Indirect Effects Characterization for Listed Species 

The Agency acknowledges that pesticides have the potential to exert
indirect effects upon the listed organisms by, for example, perturbing
forage or prey availability, altering the extent and nature of nesting
habitat, etc. 

In conducting a screen for indirect effects, the Agency uses the direct
effects LOCs for each taxonomic group to make inferences concerning the
potential for indirect effects upon listed species that rely upon
non-endangered organisms in these taxonomic groups as resources critical
to their life cycle.  The Agency considers pesticide-use scenarios,
resulting in RQs that are below all direct effect endangered species
LOCs for all taxonomic groups assessed to be of no concern for risks to
listed species either by direct or indirect effects. 

a. 	Indirect Effect Analyses Where One or More Animal Taxonomic Group
RQs Exceed the Endangered Species LOC tc \l4 "a. 	Indirect Effect
Analyses Where One or More Animal Taxonomic Group RQs Exceed the
Endangered Species LOC 

In cases where screening-level acute RQs for a given animal group equal
or exceed the endangered species acute LOC, the Agency uses the dose
response relationship from the toxicity study used for calculating the
RQ to estimate the probability of acute effects associated with an
exposure equivalent to the EEC.  This information serves as a guide to
establish the need for and extent of additional analysis that may be
performed using Services-provided “species profiles” as well as
evaluations of the geographical and temporal nature of the exposure to
ascertain  if a not likely to adversely affect determination can be
made.  The degree to which additional analyses are performed is
commensurate with the predicted probability of adverse effects from the
comparison of dose response information with the EECs.  The greater the
probability that exposures will produce effects on a taxa, the greater
the concern for potential indirect effects for listed species dependant
upon that taxa, and therefore, the more intensive the analysis on the
potential listed species of concern, their locations relative to the use
site, and information regarding the use scenario (e.g., timing,
frequency, and geographical extent of pesticide application) Greatest
concerns would exist when exposure is associated with a risk higher than
the effects probability associated with the non-endangered LOC for a
pesticide with an average slop of 4.5.  When the Agency can, upon
additional analysis at the screening level, support a not likely to
adversely affect determination, the basis for the conclusion is
documented in the endangered species section of the risk assessment. 
When the screening level assessment indicates a not likely to adversely
affect can not be determined with this level of refinement, the findings
and rationale are documented and additional analysis of the geographical
and temporal nature of the exposure, as well as more in-depth
evaluations of the biological and ecological requirements of potentially
indirectly impacted species are addressed, as described in section VI,
to ascertain whether a not likely to adversely affect determination can
be made. 

When screening-level chronic RQs for a given animal group equal or
exceed the endangered LOC there may be a potential concern for indirect
effects.   The Agency then considers the nature of the chronic
toxicological endpoint, Services-provided “species profiles”, and
further evaluation of the geographical and temporal nature of the
exposure to determine if a rationale for a not likely to adversely
effect determination is possible. When the Agency can, upon additional
analysis at the screening step, support a not likely to adversely affect
determination the basis for the conclusion is documented within the
endangered species section of the risk assessment. When the screening
level assessment or chronic effects indicates a not likely to adversely
affect can not be determined with this level of refinement, the findings
and rationale are documented and additional analysis of the geographical
and temporal nature of the exposure, as well as more in-depth
evaluations of the biological and ecological requirements of potentially
indirectly impacted species are addressed, as described in section VI,
to ascertain whether a not likely to adversely affect determination can
be made.

In making decisions about the need and scope of additional indirect
effects analysis for one or more listed species, the Agency considers
the degree to which exposures exceed any acute or chronic levels of
concern.  The greater extent to which exposures produce effects or
exceed  LOCs, the greater the concern for potential indirect effects and
therefore the more intensive the analysis on the potential listed
species of concern, their locations relative to the use site, and
information regarding the use scenario (e.g., timing, frequency, and
geographical extent of pesticide application).

b. 	Indirect Effects Where One or More Plant Taxonomic Group RQs Exceed
the Endangered Species LOC

 tc \l4 "b. 	Indirect Effects Where One or More Plant Taxonomic Group
RQs Exceed the Endangered Species LOC 

If plant RQs fall between the endangered species and non-endangered
species LOCs, the Agency concludes a no effect determination for listed
species that rely on multiple plants species to successfully complete
their life cycle (termed plant dependent species).  If plant RQs fall
between the endangered species and non-endangered species LOCs, the
Agency assumes a potential for adverse effects to those listed species
that rely on a specific plant species in their life cycle (termed plant
species obligates).  In these situations the Agency may determine if
listed organisms that are considered plant species obligates are within
the pesticide use area.  This is accomplished through a comparison of
Services-provided “species profiles” and listed species location
data. If no plant species obligates are within the pesticide use area, a
no effect determination is made for indirect effects upon plant
dependant listed species.  The Agency may also consider temporal and
geographical nature of exposure and the scope of available effects data
to determine if any potential effects can be determined to be not likely
to adversely effect a plant species obligate. The greater extent to
which exposures produce effects or exceed  LOCs, the greater the concern
for potential indirect effects and therefore the more intensive the
analysis on the potential listed species of concern, their locations
relative to the use site, and information regarding the use scenario
(e.g., timing, frequency, and geographical extent of pesticide
application).  If a no effect determination or, after additional
analysis, a not likely to adversely affect determination cannot be
supported at the screening level, the results of the assessment and any
identified lists of plant species obligates documented and additional
analysis of the geographical and temporal nature of the exposure, as
well as more in-depth evaluations of the biological and ecological
requirements of potentially indirectly impacted species are addressed,
as described in section VI, to ascertain whether a not likely to
adversely affect determination can be made.

If plant RQs are above non-endangered species LOCs, the Agency
considers this to be indicative of a potential for adverse effects to
those listed species that rely either on a specific plant species (plant
species obligate) or multiple plant species (plant dependant) for some
important aspect of their life cycle.  The Agency may determine if
listed organisms for which plants are a critical component of their
resource needs are within the pesticide use area.  This is accomplished
through a comparison of Services-provided “species profiles” and
listed species location data.  If no listed organisms that are either
plant species obligates or plant dependant reside within the pesticide
use area, a no effect determination on listed species is made.  If plant
species obligate or dependent organisms may reside within the pesticide
use area, the Agency may consider temporal and geographical nature of
exposure, and the scope of the effects data, to determine if any
potential effects can be determined to not likely adversely effect a
plant species obligate or dependant listed organism.  If a no effect
determination or,  after additional analysis a not likely to adversely
affect determination, cannot be supported at the screening level, the
results of the assessment and any identified lists of plant species
obligate and dependant listed organisms are documented and additional
analysis of the geographical and temporal nature of the exposure, as
well as more in-depth evaluations of the biological and ecological
requirements of potentially indirectly impacted species are addressed,
as described in section VI, to ascertain whether a not likely to
adversely affect determination can be made.  

In all cases, the analysis of indirect effects is presented in a
transparent manner in the endangered species section of the
screening-level risk assessment.

5.  Critical Habitat for Listed Species tc \l3 "5.  Critical Habitat for
Listed Species 

The Agency believes that the risk assessment analysis for listed
species’ indirect effects is relevant and provides a basis for an
analysis of potential effects on a listed species’ designated critical
habitat, when such a designation has been prepared by the Services. 
Because pesticides directly impact living organisms, critical habitat
analysis for pesticides is limited in a practical sense, to those
principle constituent elements of critical habitat that are of a
biological nature (e.g., the biological resource requirements for the
listed species associated with the critical habitat). To the extent that
principle constituent elements have been established by the Services in
“critical habitat profiles”, the available indirect effects
screening approach can be applied directly to those elements.  In
situations where available  “critical habitat profiles” do not
directly identify principle constituent elements,  screening-level LOCs
used to evaluate indirect effects for the associated  listed species
(from the Services “species profiles”), are used in a manner similar
to that described in V.C.4 above.  A screening-level determination of
potential modification upon designated critical habitat also
incorporates spatial analysis, when such spatial coverage is readily
available from the Services, to determine the overlay of designated
habitat with the pesticide use area.  The Agency discusses the critical
habitat analysis, along with the information material to that analysis,
in the endangered species section of the risk assessment.

6.  Description of Assumptions, Uncertainties, Strengths, and
Limitations of the Assessment tc \l3 "6.  Description of Assumptions,
Uncertainties, Strengths, and Limitations of the Assessment  

a.  Assumptions and Limitations Related to Exposure for All Taxa tc \l4
"a.  Assumptions and Limitations Related to Exposure for All Taxa 

Screening-level risk assessments rely on labeled statements of the
maximum rate of pesticide application, the maximum number of
applications, and shortest interval between applications.  Together,
these assumptions constitute a maximum use scenario.  The frequency at
which actual uses approach these maximums is dependant on local pest
pressure, resistance to the pesticide, timing of applications, and
market forces.  As discussed in the problem formulation section, the
risk assessment team collaborates with BEAD to determine more typical
use rates and application frequencies in order to provide risk managers
with a more complete characterization of uses and their implications for
ecological risk.

b. Assumptions and Limitations Related to Exposure for Aquatic Species
tc \l4 "b. Assumptions and Limitations Related to Exposure for Aquatic
Species 

(1).  Location of Species and Receiving Waters to Treated Field

 tc \l5 "(1).  Location of Species and Receiving Waters to Treated Field

 As discussed earlier in the aquatic exposure section of this document,
OPP’s screening risk assessment assumes that the modeled water body is
adjacent to the treated field.  A possible case-specific modification to
this assumption of adjacent location of the water body may be a downwind
offset of the water body if spray drift buffers are included in the
proposed product labeling.

For screening-level risk assessment purposes, the actual habitat
requirements of any particular aquatic species are not considered. 
Instead an assumption is made that unspecified aquatic listed fish and
invertebrate species occupy, exclusively and permanently, the water body
being modeled.  

With the possible exception of scenarios where pesticides are directly
applied to water, it is assumed that no habitat use considerations
specific for any species would place the organisms in closer proximity
to pesticide use sites.  An assumption of exclusive and permanent
occupation of a modeled site represents the highest possible screening
assumption of frequency within a treated or exposed area.

(2).  Exposure for Aquatic Species Is Through the Dissolved Phase tc \l5
"(2).  Exposure for Aquatic Species Is Through the Dissolved Phase 

For water column species, an assumption is made that the greatest
bioavailable fraction of pesticide in surface waters is that which
occurs as freely dissolved in the water column.  Additional chemical
exposure from materials associated with suspended solids or those
associated with food items is not considered.  In most currently
registered pesticide cases, solids adsorption and bioconcentration
occurs at lower levels than would be expected for such classically
persistent bioaccumulative compounds as dioxins, halogenated biphenyls,
some organochlorine pesticides, and some organometallics.  The extent to
which consideration of exposures to pesticide from suspended solids and
diet is not quantified by the Agency and in situations where RQs fall
close to the endangered species LOCs, the potential for additional
exposure from these routes may be a limitation of the screening
assessment.

(3).  Dissipation in the Modeled Water Body tc \l5 "(3).  Dissipation in
the Modeled Water Body 

Mass transport losses of pesticide from the modeled water body, except
for losses by volatilization, degradation and sediment partitioning, are
not considered.  Consequently, the current modeled water body is assumed
to capture all mass of pesticide entering as runoff, drift, and
erosion-associated material.  It is also assumed that pesticide mass is
never lost from the water body by overtopping or flow-through, nor is
concentration reduced by dilution.  In total, these assumptions lead to
a near maximum possible aqueous concentration.

The current water body model does not account for any potential to
concentrate pesticide through the evaporative loss of water.  This
limitation may have the greatest impact on the model’s predictive
ability for shallow water bodies, particularly vernal pools and
potholes, where high surface-to-volume ratios of the water body
accentuate the rate of evaporative loss and where the pesticide has low
rates of degradation and volatilization.  OPP is evaluating other models
that will consider variations in water body volume and consider the
effect of evaporative loss on concentrations of the pesticide and
expects to present them to the SAP in 2004.  As the Services research on
the characteristics of vernal pools advances, the Agency and the
Services will collaborate in developing future models for these exposure
scenarios.

(4).  Averaging Times for Aquatic Exposure tc \l5 "(4).  Averaging Times
for Aquatic Exposure 

For an acute risk assessment there is no averaging time for exposure. 
An instantaneous peak concentration, with a 1 in 10 year return
frequency, is assumed.  The use of the instantaneous peak assumes that
instantaneous exposure is of sufficient duration to elicit acute effects
comparable to those observed over more protracted exposure periods
tested in the laboratory, typically 48 to 96 hours.   In the absence of
data regarding time-to-toxic event analyses and latent responses to
instantaneous exposure, the degree to which risk is overestimated cannot
be quantified.

For chronic exposure risk assessments, the averaging times considered
for exposure are commensurate with the duration of invertebrate
life-cycle or fish-early life stage tests (21-28 days for invertebrates
and 56-60 days for fish).  Response profiles (time to effect and latency
of effect) to pesticides likely vary widely with mode of action and with
species and should be evaluated on a case-by-case basis as available
data allow.  Nevertheless, because the Agency relies on chronic exposure
toxicity endpoints based on a finding of no observed effect, the
potential for any latent toxicity effects or  averaging time assumptions
to alter the conclusions of an acceptable chronic risk assessment
prediction is limited.  The extent to which modeled durations of aqueous
concentrations over- or underestimate actual exposure scenarios depends
on such factors as localized meteorological conditions, runoff 
characteristics of the watershed (soils and topography), the
hydrological characteristics of receiving waters, the fate
characteristics of the pesticide active ingredient, and the method of
pesticide application.

It should be noted that chronic effects studies are performed using a
method that holds  water concentrations in a steady state.  This method
is not likely to reflect conditions associated with pesticide runoff. 
Over the course of a typical run of the aquatic exposure models,
pesticide estimated concentrations increase and decrease in surface
water on a cycle influenced by rainfall events and degradation rates.

(5).  A Well-Mixed Pond tc \l5 "(5).  A Well-Mixed Pond 

Because the EXAMS model assumes instantaneous equilibrium and mixing, it
does not consider the potential for higher short-term concentrations in
the areas of the pond initially receiving pesticide  runoff (e.g., the
shallow, near-shore areas of the pond) and drift (e.g., the near-surface
layer of the pond).  It is possible that concentrations immediately
following introduction of runoff or drift will be higher in some areas
of the pond than those modeled on the basis of instantaneous
distribution of the chemical throughout the pond.  However, the
countering assumption of no averaging time for acute risks may lead to
overestimation of  exposures throughout the water body, as described
previously.

The Agency is actively pursuing modeling techniques to possibly allow
for greater or lesser dilution of surface runoff by receiving waters. 
These approaches, which are scheduled for SAP review in February 2004,
may enhance the future understanding of water body residue levels near
shore and near surface.  

(6).  Watershed to Pond Ratio tc \l5 "(6).  Watershed to Pond Ratio 

One parameter affecting estimates of aqueous concentrations within the
PRZM/EXAMS model concerns the relationship of watershed area to pond
volume.  The assumption of a 10- hectare field running off to a
1-hectare pond of 2-meters depth is based on the USDA Natural Resource
Conservation Service design criteria for farm pond construction.. 
Actual watershed to pond volume relationships, though, are driven by
site characteristics (soil types, slopes, and meteorology). 

It is possible that larger treated watershed areas will result in more
mass of pesticide running off to the pond.  However, this
screening-level runoff may become insignificant when the watershed area
becomes so large that it precludes a reasonable assumption of a closed
pond with no outlets.  The Agency believes, based on professional
judgment, that the currently used screening watershed area to pond
volume overestimates likely aqueous concentrations. As a result, it is
evaluating other models that will consider variations in water body
volume and expects to present them to the SAP in 2004.

(7).  100 Percent Pesticide Treatment of the Pond Watershed tc \l5 "(7).
 100 Percent Pesticide Treatment of the Pond Watershed 

The Agency assumes that 100 percent of the watershed is treated with the
pesticide, which would result in a maximum possible exposure.  This
assumption may be realistic for small water bodies with associated small
watershed areas, but for large watersheds, it would result in an
overestimation of exposure. 

(8).  Frequency of Exposure During a Given Year - 1 in 10 Year Return
Frequency tc \l5 "(8).  Frequency of Exposure During a Given Year - 1 in
10 Year Return Frequency 

Screening assessments rely on events (either instantaneous or over an
averaging period) that have a return frequency of 1 in 10 years.  This
is calculated using the peak value of each of the 36 years modeled.  The
1 in 10 return frequency does not necessarily represent a 90th
percentile of all peaks over the years modeled.  Existing surface water
modeling outputs provide daily estimates of pesticide concentrations,
which can be used to more completely characterize exposure, when
required.  The Agency has reviewed a number of these model time series
for both persistent and non-persistent compounds used as multiple
applications per year and has determined that the 1 in 10 year return
frequency peak commonly represents a value farther out on the upper
bound of the distribution of daily concentrations than the 90th
percentile, with some cases being greater than the 99.9 percentile.

(9).  Dilution of Sediment tc \l5 "(9).  Dilution of Sediment  

The EXAMS model estimates of water concentration are based on an
equilibrium 

established between the compartments of the pond, principally water and
sediments.  In real world situations, sediments are constantly being
added to water bodies from the erosion of the watershed.  Over time,
this has the effect of increasing the mass of the sediments compartment,
though the actual exchange area with overlying water may remain
relatively constant.  In EXAMS, the mass of the sediment compartment
remains constant and serves as the denominator for estimating sediment
concentrations, and through equilibrium assumptions, influences
estimates of surface water concentrations.  In cases where chemicals
have appreciable stability in the environment, the EXAMS pond model will
tend to overestimate the concentration in pond sediments because it does
not allow for renewed sediment mass following runoff events.  This may
lead to higher predicted concentrations in both sediments and surface
water  because equilibrium is assumed between the two compartments.

(10).  Spray Drift tc \l5 "(10).  Spray Drift  

Surface water modeling using PRZM/EXAMS assumes 5% and 1% drift
integrated across the surface of a pond adjacent to a treated field for
aerially and ground applied pesticides, respectively.  A comparison of
these assumed values can be made with those from the first
screening-level drift predictions from the AgDrift model.  The following
table presents AgDrift predictions for deposition of drift (fraction of
applied pesticide amount) integrated across the surface of a standard
pond which is immediately adjacent to a treated field and which has a 

208.7-foot downwind width.  In situations where the Agency’s screening
models suggest that spray drift is a significant source of exposure and
therefore risk, the following information is considered in the risk
characterization to evaluate the confidence of risk assessment
conclusions.

Application Method	PRZM/EXAMS Drift		  AgDrift Model Drift

Ground 

Low Boom Height		1%			0.17 % very fine to fine spray, 50th percentile

 of measured data

0.36 % very fine to fine spray, 90th percentile of measured data

0.1 % fine to medium/coarse spray, 50th percentile of measured data

0.19 % fine to medium/coarse spray, 90th percentile of measured data

High Boom Height		1%			0.6 % very fine to fine spray, 50th percentile

of measured data

0.78% very fine to fine spray, 90th percentile of measured data

0.16 % fine to medium/coarse spray, 50th percentile of measured data

0.28 % fine to medium/coarse spray, 90th percentile of measured data

Application Method	PRZM/EXAMS Drift		AgDrift Model Median Drift,

90th Percentile Application Conditions 

(Based on Best Professional Judgment)

Aerial				5%			0.7% coarse to very coarse spray

8.9% medium to coarse spray

12.7% fine to medium spray

24.3% very fine to fine spray

From this comparison, the baseline assumptions of drift currently used
for PRZM/EXAMS modeling exceed the 90th percentile of drift predictions
from AgDrift modeling for ground applications.   The baseline drift
assumption currently used for aerial application scenarios likely
represents drift levels in excess of 90th percentile application
conditions for coarse to very coarse sprays.  However, aerial drift
assumptions are below drift levels predicted by AgDrift for very fine to
medium/coarse  sprays using 90th percentile application conditions.  The
exact extent to which the currently used aerial drift assumption
represents more frequently encountered application conditions is not
presently quantified.  

The extent to which a 5% versus another drift assumption alters
estimated aqueous concentration estimates depends on specific use
scenarios and can be influenced by the degree to which runoff
contributes to the overall receiving water concentration.  For example,
if a persistent pesticide with low affinity for soils is used in a high
runoff potential use area, drift may be only a minor route for pesticide
loading to the receiving waters and the magnitude of assumed  drift may
have a limited effect on the concentration estimate.  However, for
non-persistent chemicals with high affinity for soils used in low runoff
areas, drift may be the dominant route of pesticide entering receiving
waters, and the assumptions of that drift may appreciably influence
pesticide aqueous concentrations estimates.

It should be noted that the baseline drift assumptions for a water body
located adjacent to a treated field are much higher than upper bound
values for water bodies located at greater distances from the treated
area.  The table below shows distances from the treated area where
AgDrift assumptions for aerial drift to a water body would be
approximated by the baseline drift assumption of 5%.  Water bodies
located closer to the treated field than shown below would be predicted
to have drift loadings greater than the 5% assumption.  The greater the
distance from the treated field required to reach 5% drift, the greater
the likelihood that actual water bodies could receive drift levels
higher than the baseline 5% assumption.

Spray Category			Water Body Distance from Treated Field 

to Reach 5% Surface Integrated Drift 

in AgDrift Model (ft)

Coarse to very coarse spray			13.12

Medium to coarse spray			39.4 

Fine to medium spray				105 

Very fine to fine spray			643 

This comparison suggests that the OPP assumption of 5% aerial drift
would reasonably represent high-end estimates of drift for most water
bodies when medium to very coarse sprays are used because a few water
bodies are usually found within 40 feet of treatment areas.  However,
for very fine to medium spray uses, the confidence that the 5% drift
assumption adequately characterizes drift to water bodies is diminished
because a higher number of water bodies can be assumed to be located
within 650 feet from treated fields.  It should be noted that
quantitative probabilities of water body locations from treated fields
are likely to be crop and regionally specific.

The Agency includes a discussion of the impacts of chemical use specific
estimates of drift as computed by AgDrift in the risk characterization
and evaluates the extent to which alternative drift estimates may impact
overall risk conclusions.  Pesticide application conditions indicated by
the product labels or agronomic practices associated with a specific
crop or target pest are evaluated with respect to their associated
droplet spectra.  These expected spectra are compared with the AgDrift
model predictions of drift to determine if default drift assumptions
employed in EEC modeling are over- or underestimates. The degree to
which drift is over or underestimated is considered when establishing
bounds around EEC predictions and the extent to which these bounds lead
to RQs that exceed listed species LOCs, or not, is presented.

c. Assumptions and Limitations Related to Exposure for Terrestrial
Animals tc \l4 "c. Assumptions and Limitations Related to Exposure for
Terrestrial Animals 

(1).   Location of Wildlife Species tc \l5 "(1).   Location of Wildlife
Species 

For screening terrestrial risk assessments for listed species, a generic
bird or mammal is assumed to occupy either the treated field, or
adjacent areas receiving pesticide at a rate commensurate with the
treatment rate on the field.  Spray drift model predictions suggest that
this assumption leads to an overestimation of exposure to species that
do not occupy the treated field.  AgDrift estimated drift to areas
removed from the treated fields (below) indicates that off site drift is
but a fraction of on-field treatment rate.

Spray Droplet Size		AgDrift Model Drift Point Estimates 0 to 990 ft from
Field 

Assumption			(Tier 1)

Very fine-fine			50% to 4%

Fine to medium		50% to 1%

Medium to coarse		50% to 0.5%

Coarse to very coarse		50% to 0.3%

For screening risk assessment purposes, the actual habitat requirements
of any particular terrestrial species are not considered, and it is
assumed that species occupy, exclusively and permanently, the treatment
area being modeled.  This assumption leads to a maximum level of
exposure in the risk characterization.  To the extent that a species
does not reside exclusively and permanently in treated areas, exposure
will be less, and presumably significantly less.

(2).  Routes of Exposure tc \l5 "(2).  Routes of Exposure 

Screening-level assessments for spray applications of pesticides
consider dietary exposure alone.  Other routes of exposure, not
considered in the assessment, are discussed below:

Incidental Soil Ingestion Exposure 

The screening-level risk assessment does not consider incidental soil
ingestion.  Available data suggests that up to 15% of the diet can
consist of incidentally ingested soil depending upon species and feeding
strategy (Beyer et al. 1994).  A simple first approximation of soil
concentration of pesticide from spray application shows the effect of
not considering incidental soil ingestion:

Assuming an application of 1 pound /acre (1.12 kg/ha) of pesticide to a
bare, very low density soil (1 g/cm3) incorporated to only 1-cm depth
(actual incorporation depths may range from 5 to 20 cm), the following
soil concentrations can be calculated for a depth of 1 cm:

soil concentration = 

(((1.12 kg/ha)(1,000,000 mg/kg))/(100,000,000 cm3/ha)))(1 cm3/0.001 kg) 
= 11.2 mg/kg

Including this concentration into the standard screening-level method
and assumptions for food item pesticide residues (e.g., 240 ppm residue
assumption for short grass) shows that ingestion of soil at an
incidental rate of up to 15% of the diet would not increase dietary
exposure.  In fact, for the majority of food items, inclusion of soil
into the diet would effectively reduce the overall dietary concentration
as compared to the present assumption of the entire diet consisting of
the food source contaminated as per Fletcher et al. (1994)
recommendations. 

 Inhalation Exposure

The screening risk assessment does not consider inhalation exposure. 
Such exposure may occur through three potential sources:  (1) spray
material in droplet form at time of application, (2) vapor phase
pesticide volatilizing from treated surfaces, and (3) airborne
particulate (soil, vegetative material, and pesticide dusts).

Available data suggest that inhalation exposure at the time of
application is not an appreciable route of exposure for birds. 
According to research on mallards and bobwhite quail, respirable
particle size in birds (particles reaching the lung)  is limited to a
maximum diameter of 2 to 5 microns (U.S. Environmental Protection
Agency,  1990).  The spray droplet spectra covering the majority of
pesticide application situations (AgDrift model scenarios for very-fine
to coarse droplet applications) suggests that less than 1% of the
applied material is within the respirable particle size. 

Theoretically, inhalation of pesticide active ingredient in the vapor
phase may be another source of exposure for some pesticides under some
exposure situations.  Under laboratory conditions established to mimic
pesticide application to a field, Driver et al. (1991) demonstrated that
organophosphate exposure via inhalation produced significant short-term
acetylcholinesterase inhibition in exposed birds.  The flux of pesticide
from treated plant and soil surfaces can be appreciable for soil
fumigants.  However, the assessment of pesticide flux from treated
surfaces and its subsequent distribution within the overlying atmosphere
is complex and highly situation-specific, negating any confident generic
assumptions regarding significance.  Recognizing these limitations the
Agency is evaluating options for modeling vapor phase exposures,
including approaches for establishing near-field, near-ground air
concentrations based upon equilibrium and kinetics-based air models. 
The Agency is also working on methods to account for potential
differences in toxic potency of pesticide active ingredients when
available toxicity data are limited.  It is anticipated that these
modeling approaches and toxicity extrapolation methods will be presented
to the Agency’s SAP in 2004 for avian risk assessment, and subsequent
approaches for other taxa will be developed and incorporated into the
risk assessment process based on the results of the avian peer review.

The impact from exposure to dusts contaminated with the pesticide cannot
be assessed generically as partitioning issues related to application
site soils and chemical properties render the exposure potential from
this route highly situation specific.

Dermal Exposure 

The screening assessment does not consider dermal exposure, except as it
is indirectly included in calculations of RQs based on lethal doses per
unit of pesticide treated area.  Dermal exposure may occur through three
potential sources:  (1) direct application of spray to terrestrial
wildlife in the treated area or within the drift footprint, (2)
incidental contact with contaminated vegetation, or (3) contact with
contaminated water or soil.  

Recent Agency refined risk assessment efforts for select mosquito
adulticides and investigations into tools for quantifying dermal
exposure suggest that interception of spray and incidental contact with
treated substrates may pose risks to avian wildlife.  In addition,
research conducted by Driver et al. (1991) on northern bobwhite quail
exposed to treated vegetation suggests that, for the organophosphate
methyl parathion, dermal exposure may be a major contributor to avian
dose under simulated field conditions.  The available measured data
related to wildlife dermal contact with pesticides are extremely
limited.  The Agency is actively pursuing modeling techniques to account
for dermal exposure via direct application of spray and by incidental
contact with vegetation.  Presentation of these modeling approaches and
toxicity extrapolation methods to the SAP is expected to occur in 2004
for avian risk assessment, and subsequent approaches for other taxa will
be developed and incorporated into the risk assessment process based on
the results of the avian peer review.

Drinking Water Exposure

Drinking water exposure to a pesticide active ingredient may be the
result of consumption of surface water or consumption of the pesticide
in dew or other water on the surfaces of treated vegetation.  For
pesticide active ingredients with a potential to dissolve in runoff,
puddles on the treated field may contain the chemical.  Similarly,
pesticides with lower organic carbon partitioning characteristics and
higher solubility in water have a greater potential to dissolve in dew
and other water associated with plant surfaces.  Estimating the extent
to which such pesticide loadings to drinking water occurs is complex and
would depend upon the partitioning characteristics of the active
ingredient, the types of soils of the treatment area, and the
meteorology of the treatment area.   In addition, the use of various
water sources by wildlife is highly species-specific.  As a result, the
Agency is actively developing processes to quantify drinking water
exposures from field puddles and dew.  An initial screening approach for
modeling drinking water exposure has been presented to the Agency’s
SAP and modifications to these modeling approaches are expected to
undergo SAP review in 2004.

(3).  Incidental Pesticide Releases Associated with Use tc \l5 "(3). 
Incidental Pesticide Releases Associated with Use 

Agency risk assessments are based on the assumption that the entire
treatment area is subject to pesticide application at the rates
specified on the label.  In reality, there is the potential for uneven
application of the pesticide through such plausible incidents as changes
in calibration of application equipment, spillage, and localized
releases at specific areas of the treated field that are associated with
specifics of the type of application equipment used (e.g., increased
application at turnabouts when using older ground application
equipment). The Agency does not quantitatively account for such
incidental releases of pesticides associated with labeled uses of the
products, but it does indicate where such situations have resulted in
wildlife mortality incidents and discusses this source of uncertainty in
the risk characterizations.

(4).  Residue Levels Selection tc \l5 "(4).  Residue Levels Selection  

As discussed earlier in the exposure section of this document, the
Agency relies on the work of Fletcher et al. (1994) for setting the
assumed pesticide residues in wildlife dietary items.  The Agency
believes that these residue assumptions reflect a realistic upper-bound
residue estimate, although the degree to which this assumption reflects
a specific percentile estimate is difficult to quantify.  Fletcher et
al.(1994) maintains that the pesticide active ingredient residue
assumptions employed by the Agency represent a 95th percentile estimate.
 In contrast to the Fletcher evaluation, field measurement efforts by
Pfleeger et al. (1996) indicated that the Agency assumption of residues
for short grass, broadleaf forage, and fruits were not exceeded.  Agency
predictions of residues were exceeded by 16% of long grass measurements,
and 21% of seed/pod measurements.  Finally, Baehr and Habig (2000)
compared Agency residue assumptions with distributions of measured
pesticide residues from the Agency’s UTAB  database.  This comparison
suggested that Agency residue assumptions (1) exceed the 99th percentile
of the UTAB distribution for short grass and long grass, fall just below
the 95th percentile for forage, and (2) fall between the 95th and 98th
percentiles for fruits and seeds.

It is important to note that the field measurement efforts used to
develop the Fletcher estimates of exposure involve highly varied
sampling techniques.  It is entirely possible that much of these data
reflect residues averaged over entire above ground plants in the case of
grass and forage sampling.  Depending upon a specific wildlife
species’ foraging habits, whole above-ground plant samples may either
underestimate or overestimate actual exposure.  For example, wildlife,
feeding on the tops of forage plants after application, may be exposed
to higher concentrations of pesticide in plant tops than predicted by
sampling efforts focusing on whole above-ground plant measurements

(5).  Dietary Intake - The Differences Between Laboratory and Field
Conditions tc \l5 "(5).  Dietary Intake - The Differences Between
Laboratory and Field Conditions 

Acute and chronic risk assessments rely on comparisons of wildlife
dietary residues with LC50 or NOEC values expressed in concentrations of
pesticides in laboratory feed.  These comparisons assume that ingestion
of food items in the field occurs at rates commensurate with those in
the laboratory.  Although the screening assessment process adjusts
dry-weight estimates of food intake to reflect the increased mass in
fresh-weight wildlife food intake estimates, it does not allow for gross
energy and assimilative efficiency differences between wildlife food
items and laboratory feed.  The significance of the gross energy content
between laboratory feed and “field” diet can be seen in the
following example:

A typical laboratory avian feed, as used, contains approximately 2750
kcal/ kg.

The Agency’s Wildlife Exposure Factors Handbook (U.S. Environmental
Protection Agency, 1993) presents the following dry-weight and fresh
weight caloric contents for selected wildlife food items:

Food Item		Energy Dry (kcal/kg)		Energy Fresh (kcal/kg)

grasses			4200				1300

broadleaf forage		4200				2200

seeds				5100				4700

fruits				2000				1100

insects				5600				1600

On gross energy content alone, direct comparison of a laboratory dietary
concentration-based effects threshold to a fresh-weight pesticide
residue estimate would result in an underestimation of field exposure by
food consumption by a factor of 1.25 - 2.5 for most food items.  Only
for seeds would the direct comparison of dietary threshold to residue
estimate lead to an overestimate of exposure.

Differences in assimilative efficiency between laboratory and wild diets
suggest that current screening assessment methods are not accounting for
a potentially important aspect of food requirements.  Depending upon
species and dietary matrix, bird assimilation of wild diet energy ranges
from 23 - 80%, and mammal’s assimilation ranges from 41 - 85% (U.S.
Environmental Protection Agency, 1993).  If it is assumed that
laboratory chow is formulated to maximize assimilative efficiency (e.g.,
a value of 85%), a potential for underestimation of exposure may exist
by assuming that  consumption of food in the wild is comparable with
consumption during laboratory testing.

In the screening process, exposure may be underestimated because
metabolic rates are not related to food consumption.   For example, the
Wildlife Exposure Factors Handbook (U.S. Environmental Protection
Agency, 1993) includes allometric models for estimating both existing
metabolic rate (EMR) and free living metabolic rate (FMR).  EMR is the
metabolic rate necessary for animal maintenance in captivity without
body weight loss, a condition similar to caged test animals.  FMR is the
energy requirement for an organism in the wild.  For passerine birds
these relationships are as follows:

EMR (kcal/day) = 1.572 (body weight g) 0.6210

FMR (kcal/day) = 2.123 (body weight g) 0.749

Using a weight range for passerines of 10 - 150 g, the EMR predictions
range from 6.6 to 35.3, and the FMR ranges from 11.9 to 90.5 kcal/day . 
Thus, it appears that not accounting for increased energy demands of
organisms in the wild when comparing dietary residues to dietary
toxicity thresholds represents about a two-fold underestimation in
exposure potential.

Finally, the screening procedure does not account for situations where
the feeding rate may be above or below requirements to meet free living
metabolic requirements.  Gorging behavior is a possibility under some
specific wildlife scenarios (e.g., bird migration) where the food intake
rate may  be greatly increased.  Kirkwood (1983) has suggested that an
upper-bound limit to this behavior might be the typical intake rate
multiplied by a factor of 5.  

In contrast is the potential for avoidance, operationally defined as
animals responding to the presence of noxious chemicals in their food by
reducing consumption of treated dietary elements.  This response is seen
in nature where herbivores avoid  plant secondary compounds.  For
agrochemicals, Dolbeer et al. (1994) reported that the use of methiocarb
on fruit crops reduced depredation by birds.  Of course, chemical
treatment of food sources and any subsequent avoidance of those food
sources by a species may, in itself,  result in detrimental effects on
the energetics of the species.

d. Assumptions and Limitations Related to Effects Assessment tc \l4 "d.
Assumptions and Limitations Related to Effects Assessment 

(1).  Sublethal Effects tc \l5 "(1).  Sublethal Effects   

For an acute risk assessment, the screening risk assessment relies on
the acute mortality endpoint as well as a suite of sublethal responses
to the pesticide, as determined by the testing of species response to
chronic exposure conditions and subsequent chronic risk assessment. 
Examples of these sublethal endpoints include the following:

Aquatic

Organisms	Test Type			Sublethal Measurement Endpoints

Invertebrate Life-Cycle	Production of young by first generation

Length of first generation

Fish Early Life-Stage		Embryo hatch rate

Time to hatch

Time to swim-up

Growth (length and weight)

Pathological or histological effects

Observations of other clinical signs

Fish Life-Cycle		Embryo hatch rate

Time to hatch

Growth (length)

Exposed adult egg production

Second generation hatch rate

Second generation growth

Birds		Reproduction 			Maternal weight

Eggs laid/hen

Eggs cracked

Eggshell thickness

Viable embryos

Hatchling number

14-day survivors

Gross necropsy (organ lesions, fat and muscle deterioration)

Observations of other clinical signs

Mammals	Two-Generation		Total panel of reproduction parameters
including:

Reproduction		 	histopathology, parental and offspring growth,   weight,
mating, lactation, gonadal development milestones, sexual organ
performance, and offspring production

Of course, a risk assessment team has the option of considering
additional sublethal data in the assessment.  This option is exercised
on a case-by-case basis and only after careful consideration of the
nature of the sublethal effect measured and the extent and quality of
available data to support establishing a plausible relationship between
the measure of effect (sublethal endpoint) and the assessment endpoints.
  This option includes a determination of whether there are clear,
reasonable, and plausible links between the sublethal effect and
survival or reproductive capacity of organisms in the field in
accordance with the screening assessment endpoints of survival and
reproduction capacity.  The Agency documents the findings of such
evaluations of additional sublethal effects in the effects assessment
and includes a discussion of their potential effects upon the confidence
of the overall risk assessment conclusions.  The Agency anticipates
that, through the SAP and related external peer-review processes in the
scientific community, accepted risk assessment practices will continue
to advance in this area.  As with other risk assessment techniques, when
new approaches are vetted through the peer-review process, the Agency
will continue its practice of including state-of-the-science
methodologies and anticipates collaborative efforts with the U.S. Fish
and Wildlife Service and the National Marine Fisheries Service in
developing future sublethal endpoint analysis approaches for peer
review.

(2). Age Class and Sensitivity of Effects Thresholds tc \l5 "(2). Age
Class and Sensitivity of Effects Thresholds 

It is generally recognized that test organism age may have a significant
impact on the observed sensitivity to a toxicant.  The screening risk
assessment acute toxicity data for fish are collected on juvenile fish
between 0.1 and 5 grams.  Aquatic invertebrate acute testing is
performed on recommended immature age classes (e.g., first instar for
daphnids, second instar for amphipods, stoneflies and mayflies, and
third instar for midges).  Similarly, acute dietary testing with birds
is also performed on juveniles, with mallards being 5 -10 days old and
quail 10 - 14 days old.  

Testing of juveniles may overestimate toxicity at older age classes for
pesticidal active ingredients that act directly (without metabolic
transformation) because younger age classes may not have the enzymatic
systems associated with detoxifying xenobiotics.  However, the influence
of age may not be uniform for all compounds, and compounds requiring
metabolic activation may be more toxic in older age classes.  The
screening risk assessment has no current provisions for a generally
applied method that accounts for this uncertainty.  In so far as the
available toxicity data may provide ranges of sensitivity information
with respect to age class, the risk assessment uses the most sensitive
life-stage information as the conservative screening endpoint and
includes an evaluation of all available age-class sensitivity
information as it impacts the confidence of risk conclusions in the risk
characterization section of the document. 

(3).  Use of the Most Sensitive Species Tested tc \l5 "(3).  Use of the
Most Sensitive Species Tested 

Although the screening risk assessment relies on a selected toxicity
endpoint from the most sensitive species tested, it does not necessarily
mean that the selected toxicity endpoints reflect sensitivity of the
most sensitive species existing in a given environment.  The relative
position of the most sensitive species tested in the distribution of all
possible species is a function of the overall variability among species
to a particular chemical.  In the case of listed species, there is
uncertainty regarding the relationship of the listed species’
sensitivity and the most sensitive species tested.  

Knowledge about the inherent interspecies variability is limited to
information available from a small sampling of the overall universe of
species (i.e., a relatively small number of species actually tested) and
estimates statistically derived using classical sampling theory. 
Confidence in the use of the most sensitive species tested as a
protective estimate of listed species sensitivity is a function of the
size of the tested species pool, the representation of species tested
across taxonomic groups of interest, and the variability across measured
toxicity endpoints for the tested species.

It is likely that any given species can be arrayed throughout the
distribution of sensitivities of given taxonomic groups to pesticides. 
In the case of species-specific assessments, there may be sufficient
information on specific taxonomic groups to allow for more certain
interspecies extrapolations for closely defined toxicological endpoints.
 The Agency is presently evaluating extrapolation methods to relate
listed species or close taxonomic groups to tested species or taxonomic
groups.

Without prior knowledge about relative position of individual tested
species and a given species of concern (e.g., listed species) within the
distribution of sensitivities for a given chemical, an evaluation of the
ability of tested species to represent the most sensitive species (a
lower limit to potential sensitivity to a toxicant) provides insight
into the confidence of risk predictions to protect all species within a
taxonomic group.  This is achieved by a simple calculation:

probability of representing most sensitive species = number of tested
species/total number of species

Given the small numbers of species tested and the comparatively large
number of species for which these data are to represent, it is not
likely that tested species represent the most sensitive species within
the broad taxonomic groups used in the screening risk assessment.  For
example, if two bird species are randomly tested and there are 650
species of birds in the United States, the probability of capturing an
endpoint representing the most sensitive species is 2/650 or roughly 0.3
percent.

Another method to evaluate assumptions concerning interspecies
sensitivity is to estimate the probability of a measured value
representing an nth percentile sensitive species (i.e., some reasonable
or acceptable lower bound of potential sensitivity).  Thus, the sampling
of two 

random bird species would have a probability of encompassing the 5th
percentile species as follows:

probability of representing the 5th percentile or lower =1-(1-p)n
=(1-(1-0.05)2 = 0.0975

   Where: 	p is the target nth percentile (0.05 for this case) and

n equals the number of trials (2 for a random testing of two bird
species)

It should be noted that such evaluations cannot provide information on
the likely value of the toxicity endpoint when extrapolated from a
tested species to the most sensitive or the nth percentile species.  To
do that, it is necessary to have information on the variability of the
response among species.  This can be accomplished by looking at the
variance among tested species, provided it is accepted that the tested
species are randomly sampled from the overall population.  With only two
species sampled within a taxonomic group, estimating the variability for
the species sensitivity across that group is by nature uncertain. 
Indeed, sampling statistics would suggest that the confidence of 
predicting rare events from small sample sizes is not improved until the
sample size approaches 30.

Departing from the usual sampling statistics for testing a single
compound, toxicologists have turned to more robust data sets by looking
at the available toxicity endpoints from a variety of tested compounds
and predicting the level of sensitivity of species on the lower bounds
of the distribution (often the convention is at the 5th or 10th
percentile).  For example, Luttik and Aldenberg (1997) evaluated  55
compounds with LD50 data on birds and 69 compounds with LD50 data for
mammals.  In each case, data were available for four or more species. 
Evaluation of the distribution characteristics of these data suggested
that for small sample sizes of available LD50 data (N<4, a likely
situation for many pesticide registrations), factors of 0.175 and 0.263
applied to the geometric mean of available data would approximate a 5th
percentile species sensitivity with 50% confidence.  If greater
confidence was desired in the prediction of the 5th percentile species
sensitivity from small data sets, the extrapolation factors would be
even smaller.  For example, Luttik and Aldenberg (1997) recommended
extrapolation factors of 0.051 and 0.1, for situations where only two
bird or mammal species are tested and the 5th percentile and 95%
confidence is required.  The Agency is presently evaluating such
extrapolation methods for aquatic species.

As discussed earlier in this document, the Agency is not limited to a
base set of surrogate toxicity information in establishing risk
assessment conclusions.  The Agency also considers toxicity data on
non-standard test species (e.g., amphibian data) when available.  To the
extent that such data meet data quality requirements, it is used to
interpret the relevance of risk assessment LOCs in the context of other
tested taxa.

e.  Assumptions Associated with the Acute LOCs tc \l4 "e.  Assumptions
Associated with the Acute LOCs 

Urban and Cook (Support Document #8) presented a mathematical analysis
of the use of the 0.1 and 0.05 factor applied to the most sensitive LC50
or LD50 as the effects threshold for the acute toxicity LOC for an
endangered species.  As summarized by Urban and Cook, 0.1 (LC50) is
equivalent to an individual risk of mortality of 1 in 30 million for a
pesticide active ingredient with a probit slope of 4.5.  Re-analysis
suggests that this is in error.  The calculation of dose (LCk)
associated with a defined response for a probit slope curve is as
follows:

logLCk = logLC50 + (probit k-probit5)/b

where: LC50 equals probit 5 and b equals slope

This can also be expressed as:

 LCk = (LC50)(10z/b)

logLCk = logLC50+(z/b)

where: z is the standard normal deviate and b equals the slope

Using a 10-fold difference between the LC50 of 100 and the LCk (i.e., an
LOC threshold of 0.1(LC50)) and a typical slope of 4.5, the solution for
z would be -4.5.  This standard normal deviate corresponds to a
probability of mortality of approximately 1/300,000.  Using a plausible
range of slopes of 2 to 9 (e.g., the range of slopes with the
insecticide carbofuran) the probabilities of individual mortality ranges
from 1/50 to less than 10-16 at a LOC threshold of 0.1(LC50).

The risk characterization section of the assessment document includes an
evaluation of the potential for individual effects at an exposure level
equivalent to the LOC.  This evaluation is based on the median lethal
dose estimate and dose/response relationship established for the effects
study corresponding to each taxonomic group for which the LOCs are
exceeded.

VI.  Overview of OPP’s Species-specific Ecological Risk Assessment
Process for Aquatic

        Life, Wildlife, and Plants tc \l1 "VI.  Overview of OPP’s
Species-specific Ecological Risk Assessment Process for Aquatic       
Life, Wildlife, and Plants 

A.  Overview and Organization of FEAD tc \l2 "A.  Overview and
Organization of FEAD 

FEAD performs the following specific functions: 

Serves as domestic liaison with State and Tribal Governments and EPA
Regional Offices as well as international liaison with individual
countries and international organizations;

Develops and coordinates the development of policies and regulations;

Manages and responds to controlled correspondence and Congressional
inquiries;

Carries out routine and targeted communication activities for OPP; and 

Manages national regulatory and non-regulatory programs that rely on
regional, state and tribal government offices for field implementation. 
This includes Certification of Pesticide Applicators, Worker Protection,
Container Recycling and Design, Water Quality Protection, and Endangered
Species Protection.

To carry out these functions, FEAD is organized into five branches:
three branches that support OPP as a whole and two branches that carry
out human health related or environmentally related field programs as
follows: 

Government and International Services Branch (GISB) - Domestically, this
branch serves as liaison with EPA’s 10 regional offices and with the
state agencies designated by the Governors and Tribal governments, to
lead the pesticide regulatory program at the state and tribal levels. 
Additionally, GISB represents the Office on international issues and
with international organizations. 

Policy and Regulatory Services Branch - Manages and coordinates the
regulatory process for OPP and assists in the development of policies
related to a variety of pesticide issues. 

Communication Services Branch - Coordinates communication activities for
OPP, including the development of communication strategies on particular
issues, general educational campaigns for the public on pesticide
safety, and responses to controlled correspondence and Congressional
inquiries. 

Certification and Worker Protection Branch - Develops and implements,
through the Regional offices and State and Tribal agencies,  nationwide
programs for certifying that applicators of restricted use pesticides
are competent to perform this function.  This Branch also is responsible
for the regulatory program to ensure agricultural workers are protected
from pesticide exposures.

Environmental Field Branch - Develops and implements, through the
Regional offices and State and Tribal agencies, programs to help ensure
pesticide use does not harm water quality, regulatory programs to ensure
pesticide container integrity and containment of pesticide storage
areas, and OPP’s program to assess the risks to and provide protection
for listed species and critical habitat. 

B. Purpose of the Species-Specific and Habitat-Specific Assessments tc
\l2 "B. Purpose of the Species-Specific and Habitat-Specific Assessments

   	If  the screening-level risk assessment indicates a pesticide may
potentially impact, either directly or indirectly, listed species or
critical habitat, OPP performs a more refined assessment.  If that
assessment does not support a “not likely to adversely affect”
determination for all aspects of the action, FEAD on those aspects of
the action for which the screening level assessment has not made such a
determination.  FEAD undertakes further refinement on those aspects of
the action for which such a determination was not made.  FEAD determines
whether use of the pesticide "may affect" a particular listed species
and if so, whether it is “likely to adversely affect” the species,
or, in the case of critical habitat, whether use of the pesticide may
destroy or adversely modify any principle constituent elements for the
critical habitat, and if so, whether the expected impacts are “likely
to adversely affect” the critical habitat.  This section discusses the
steps undertaken in a species-specific or habitat-specific assessment,
which is based upon and is intended to supplement and refine the
screening-level risk assessment.  

OPP’s goal for this process is to protect the listed species and
critical habitat by potentially modifying a pesticide’s use in a
manner that is least disruptive to agriculture and other pesticide
users.  In order to accomplish this goal, refinements of the
screening-level risk assessment, which makes assumptions that the
species or habitat will be exposed at levels estimated in the
environment, focuses on refining the exposure information for listed
species or critical habitat.  The result of these steps is an “effects
determination” that the pesticide will have “no effect” on the
listed species or critical habitat, “may affect but is not likely to
adversely affect the species or critical habitat”, or “may adversely
affect the species or critical habitat.”

Any changes to the assessment assumptions, data used for risk analysis,
and risk mitigation measures that depart from the typical screening
level approach are documented and their associated impacts upon the
overall risk conclusions related to listed species is presented. Where
appropriate, the quantitative estimation of risks will be recalculated..

The first step in the process is to improve the exposure estimates based
on refining the geographic proximity of the pesticide’s use and the
listed species and/or critical habitat.  If there is no geographic
proximity, this information would support a determination that the
pesticide use will have no effect on the species or critical habitat. 
If after conducting the first step of this analysis, FEAD determines
that geographic proximity exists, FEAD examines both potential direct
effects and any potential indirect effects of the pesticide use.  

C.  Effects Determinations tc \l2 "C.  Effects Determinations 

The “effects determination” is a determination of whether the
pesticide will:

Have “no effect” on the listed species or critical habitat, 

“May affect but is not likely to adversely affect” the listed
species or critical habitat, or

“May adversely affect the species or critical habitat”.  

If during the screening-level assessment it is determined that there are
no indirect effects and LOCs for listed species are not exceeded for
direct effects, OPP declares there is “no effect” from that
pesticide’s use on listed species and critical habitats.  If, on the
other hand, indirect effects are anticipated or exposure may exceed the
LOCs for direct effects, FEAD usually declares that the pesticide’s
use “may affect” the particular listed species or critical habitat. 

If a determination is made that the pesticide’s use “may affect”
the listed species or critical habitat, FEAD uses information to help
characterize the potential for exposure at the predicted levels, and
uses best professional judgment to distinguish those actions that “may
affect but are not likely to adversely affect” a particular species or
habitat from those actions that appear “likely to adversely affect”
a listed species or critical habitat.  The information used to
characterize this degree of potential risk to a species is discussed
later in this section. 

D.  Information and Data Sources Used in the Species-specific and
Habitat-specific Assessments tc \l2 "D.  Information and Data Sources
Used in the Species-specific and Habitat-specific Assessments 

A variety of information is used in the species-specific or
habitat-specific assessment, which is intended to refine the
screening-level risk assessment to more specifically determine exposure
and characterize risk to a listed species or critical habitat. The
information used and the purpose for which it is used is described
below.  Where personal communications provide information relevant to
the assessment and characterization, this information is documented.  

   

1.  “DANGER” Program tc \l3 "1.  “DANGER” Program 

The “DANGER” program is used to identify a list of species (and
eventually critical habitats) that occur in counties where a particular
commodity is produced.  “DANGER” is a computerized database that has
been populated with county-level occurrence information for listed
species and with county-level information on agricultural crops and
their acreage.  

The county-level species locations were derived from the U.S. Fish and
Wildlife Service’s and U.S. National Marine Fisheries Service’s (the
Services) Federal Register Listing Notices and Recovery Plans, personal
communications, and other documented sources.  After compiled 
information from these sources, OPP  provided the compilation to the
Services and requested verification.  EPA incorporated the Services’
corrections and has continued to update the information in the DANGER
program with information extracted from the Services’ Listing notices.
 

The information on county-level crop occurrence and acreage within
counties of particular crops is extracted from the most recent U.S.
Department of Agriculture’s Agricultural Census
(http://www.usda.gov/nass/ ).  This Census is updated every five years .
 If it is known that a particular crop is either expanding or
diminishing in acreage, information derived from personal communications
with State agencies, commodity organizations, extension agents, etc. may
be used to supplement the information derived from the computer
database. 

OPP anticipates updating or replacing DANGER with information being
developed by the FIFRA Endangered Species Task Force (FESTF).  Through
FESTF, an industry task force, FEAD is anticipating access to element
occurrence data for listed species and a computerized information
management system that will consistently provide information on
geographic co-occurrence of potential pesticide use areas and species
location, at a finer scale than is currently available through the
DANGER program.  This system will be used by EPA to help refine
geographic proximity of pesticide use to listed species and will be used
by industry Task Force members to screen new pesticide registration
applications for potential listed species implications.  

2.  Biological Requirements and Habits of Listed Species tc \l3 "2. 
Biological Requirements and Habits of Listed Species 

The Agency’s sources of best available and current information
concerning species’ life history, ecology, population demographics,
etc., will include the Services’ species’ listing rules, species’
recovery plans (when prepared), “status review”  background
documents, and “benchmark” or “foundational” studies identified
by the Services since preparation of a listing rule or recovery plan. 
In addition, “species profiles” when prepared by the Services for
other Federal action agencies (e.g., EPA’s Office of Water) will be
provided, upon request, to the Agency by the Services.  Appropriate lead
Service Field Offices or Lead Recovery Coordinators can also be
contacted to provide any significant new information that may be
available.  In addition, information on the biological requirements and
habits of a listed species are also obtained from other sources such as
The Official World Wildlife Fund Guide to Endangered Species of North
America (D.W. Lowe et al, 1990; C.J. Mosely, 1992; W. Beacham, 1994).  

In the vast majority of situations, specific data within the above
sources of information, together with the information used in screening
level assessments, will be adequate to perform more refined analyses of
direct and indirect effects on listed species and effects on critical
habitat.  Any literature searches performed by the Agency in an attempt
to gather information beyond that which is held by the Services will be
undertaken on a case-by-case basis for specific biological information
and only when significant uncertainties remaining in a risk assessment
prevent a reasonable effects analysis. 

This information is assessed, together with data on commodity locations
and geographic features (VI. D, 3 - 4) to determine whether spatial and
temporal overlap in use and species activities and habits may result in
exposure at a level and duration that produces the effect.  This
information may also assist EPA in evaluating the potential exposure
levels and nature and magnitude of effects to listed species and
critical habitat.

3.  Sub-county Commodity Information tc \l3 "3.  Sub-county Commodity
Information 

A variety of sources such as agricultural extension agents, commodity
representatives, state departments of agriculture, etc. are considered
for obtaining sub-county information, if available.  This information is
used to identify where a commodity is grown within a county, in order to
determine whether use of a pesticide on that commodity may occur in
proximity to a listed species. 

4.  Geographic Features That May Preclude Exposure tc \l3 "4. 
Geographic Features That May Preclude Exposure 

Further expert opinion may be considered, if available, about any
geography within a county that would limit the production of a
particular crop or would limit the movement of a listed species.  This
information is used to further refine the determination of whether
pesticide use may occur in proximity to a listed species or its critical
habitat.

5.  Incident Information tc \l3 "5.  Incident Information   

The incident information (see Sections IV.C.2.c and V.B.2 for incident
information sources) from the Ecological Incident Information System and
also the ECOTOX database (though a database not specifically targeted to
the collection of incident data) described previously is reviewed for
incidents involving specific species or species that may be predictors
of effects to listed species.  This information is not used to make an
explicit determination of whether a species may be affected by a
pesticide’s use, but rather to assist in characterizing the potential
risk. 

6.  Sales and Use Information tc \l3 "6.  Sales and Use Information 

Information on sales of a particular pesticide or the amount used is
obtained, if available, from two sources.  First, in states that require
pesticide use reporting, information on the amount of a particular
pesticide used within relevant geographic areas is obtained from the
State government.  (Currently the only state data used is California’s
Pesticide Use Report data at
http://www.cdpr.ca.gov/docs/pur/purmain.htm.) Where these data are not
available, information that may be voluntarily supplied by pesticide
manufacturers is reviewed.  This information is not used to make an
explicit determination of whether a listed species may be affected by a
pesticide’s use, but rather to assist in characterizing the potential
risk. 

7.  Local Use Practices tc \l3 "7.  Local Use Practices 

Information about local use practices, including but not limited to,
numbers of applications, rates of pesticide applications, timing of
applications, and methods of application may be obtained from a variety
of sources such as regional or local commodity organizations, extension
service specialists, and state government agencies.  This information is
not used to make an explicit determination of whether a species may be
affected by a pesticide’s use, but rather to assist in characterizing
the potential risk.  

8.  Monitoring Data tc \l3 "8.  Monitoring Data 

Results of available monitoring or sampling data, including but not
limited to data generated through the U.S. Geological Survey’s
National Water Quality Assessment Program are reviewed to determine
whether a particular pesticide has been detected in relevant water
bodies.  Both the frequency of detection and the level detected are used
to better characterize the potential risk to the listed species. 
Further details on the National Water Quality Assessment Program can be
found at:  http://water.usgs.gov/nawqa/ 

E.  Exposure Characterization in the Species-Specific and
Habitat-Specific Assessments tc \l2 "E.  Exposure Characterization in
the Species-Specific and Habitat-Specific Assessments 

1.  Geographic Proximity tc \l3 "1.  Geographic Proximity 	

a.  A “DANGER” Query tc \l4 "a.  A “DANGER” Query  

OPP queries the “DANGER” program to determine in what counties a
pesticide’s use and a listed species may co-occur.  The comparison of
counties in which listed species occur, with counties in which
agricultural commodities are produced, is made to determine if there is
overlap, and thus, potential for a listed species to be exposed to a
pesticide registered on that commodity.  The result of this query is a
list of species  that occur in a county and that have the potential for
exposure to the pesticide.  EPA is working with the Services to expand
this tool to capture information regarding the location of critical
habitat, as well. This list of co-occurrences is the first refinement
and narrows the area of concern by excluding species and areas of
critical habitat that do not occur in an area where exposure could
occur.  For example, a pesticide that is registered nationally for use
on hops will only have potential to expose listed species that occur in
geographic areas where hops are grown.  The “DANGER” program will
thus exclude from the list species and habitats that are not in
geographic proximity to the pesticide’s use areas. 

b.  Sub-county Use of the Pesticide tc \l4 "b.  Sub-county Use of the
Pesticide 

For each use that potentially poses a risk of concern to listed species
or critical habitats, the geographic areas in which those uses occur, on
a sub-county basis are identified if possible.  Continuing the example
above, while hops are only grown in counties in the Pacific Northwest,
they are not grown everywhere within those counties.  Where information
is available to determine sub-county geographic areas of a given
commodity, that information is compared to species occurrence and a
determination made whether the species may be exposed.  This step may or
may not refine further the list of pesticide/species or
pesticide/habitat co-occurrences for which a potential concern exists. 

If information is available about the specific geography of an area
within a county that may limit the production of a particular crop or
that would limit the range of a listed species, this information is
compared to the list of co-occurrences to refine the list of where a
potential concern exists.  For example,  if it is known that the
county's elevation ranges from 1200 feet above sea level to 6500 feet
above sea level, and it also is known that a particular crop cannot be
grown above 4000 feet above sea level, parts of the county above that
altitude may be discounted as of potential concern.  Similarly, the
Little Kern Golden Trout occurs at rather high elevations in Fresno
County, CA, but these higher elevations are distant from the large
expanse of agricultural crops in the San Joaquin Valley of that county. 
Many listed plants occur in forests or rangeland areas far removed from
crops.  If the use being evaluated is for a crop, such species likely
will not be exposed.  Some crops, such as cranberries, are grown only in
very specific and small parts of a county and may not be near a listed
species habitat.  There is no "compendium" of such spacial distribution
information, so when it is found in the course of a risk assessment, it
is being documented and accumulated for future use.  This refinement of
geographic proximity may result in removal of some species or habitats
from the list of those for which there is a concern. 

2.  Refine Exposure Estimates Using Specific Assessment Methodologies tc
\l3 "2.  Refine Exposure Estimates Using Specific Assessment
Methodologies  

A review of the assessment methodology used in the screening-level risk
assessment is conducted to assess whether the methodology is the most
appropriate method for the species-specific or habitat-specific
assessment.  For example, an older assessment for a cotton use may
include only a Tier I exposure model using GENEEC, which is based upon a
high default potential for runoff.  But using a PRZM-EXAMS Tier 2
exposure model for a particular pesticide may indicate that the
potential aquatic exposure is considerably lower.  Even if a Tier 2
PRZM-EXAMS model was used in a cotton assessment, early assessments with
this model included a scenario only for Mississippi cotton.  But the
results of a Mississippi cotton runoff model would not be appropriate
for use in estimating environmental concentrations from cotton grown in
California because of differences in geography, soils, and
meteorological patterns.  Alternative scenarios are selected from those
developed by EFED and reflect upper bound exposure at the selected site
following procedures described in internal EFED guidance (Support
Document #81).  To the extent that additional exposure scenarios are
warranted, analyses are undertaken in concert with EFED scientists.  Any
changes to the assessment assumptions, data used for risk analysis, and
risk mitigation measures that depart from the typical screening level
approach are documented and their associated impacts upon the overall
risk conclusions related to listed species is presented.  Where
appropriate, the quantitative estimate of risks will be recalculated.

OPP does not have scenarios developed for all crops, and for many crops
the scenarios represent only one or possibly two locations.  While
additional scenarios are always under development, and OPP now has a
suite of scenarios to address most major crops and several regions, it
is seldom possible to have a model to exactly fit a particular site.  A 
species-specific or habitat-specific risk assessment will make use of a
scenario that, using best professional judgment, is the most appropriate
for a particular situation.  Assessing environmental concentrations
using a more appropriate model for the particular area of the country
where potential exposure may occur, could result in either higher or
lower predicted environmental concentrations and thus, more or fewer
species on the list of those for which there may be a concern.  

3.  Refine Exposure Based on Biological and Habitat Requirements tc \l3
"3.  Refine Exposure Based on Biological and Habitat Requirements  

For each species still of concern for direct or indirect effects, FEAD
determines whether there are any biological characteristics of the
species or habits of the species that would preclude exposure at levels
that may cause direct effects.  This refinement is based on an
evaluation of the sources listed in Section VI. D. 2.  FEAD reviews the
habitat requirements, biology and habits of each identified species to
determine whether there is any factor that would preclude exposures of
concern.  For example, if the residues of concern occur only on short
grasses, it is important to know whether the species of interest use
short grass environments as cover or food.  

For potential chronic effects identified in the screening-level risk
assessment, FEAD focuses on whether there is temporal overlap in
pesticide residues and species activities and habits that may result in
exposure at a level and duration that produces the effect.  For example,
while a pesticide may be in the environment at levels that could cause
an effect given a certain duration of exposure, a species that migrates
through the area may not experience exposure for a duration long enough
to results in that effect.  On the other hand, a species that occurs in
the area and does not migrate, may have exposure durations that could
result in the effect. 

F.  Risk Characterization tc \l2 "F.  Risk Characterization  

After the species-specific or habitat-specific assessment is completed,
FEAD documents those situations that resulted in a determination that
the pesticide had “no effect” on the listed species.  FEAD will
determine that an action “may affect” a listed species if the RQ
exceeds the endangered species LOC, and a species-specific analysis
indicates temporal and spatial overlap between pesticide use and the
species presence, except when specific information (e.g., data on the
mode of action) demonstrates that the listed species would not be
affected.  For “may  affect” determinations, FEAD distinguishes
between those that “may adversely affect” the species or habitat and
those that “may affect but are not likely to adversely affect” the
species or habitat.  Where the species-specific assessment results in a
conclusion that there are no indirect effects nor exposure at levels
that may result in direct effects, the review is concluded with a
determination of  “no effect.”  All other determinations therefore,
involve either indirect effects or some level of potential exposure that
may result in direct effects.

The distinction between those situations in which FEAD makes a “likely
to adverse effect” determination versus those in which it determines
the pesticide “may affect but is not likely to adversely affect” the
species, is made using best professional judgment about the significance
and likelihood of the effects.  In making this judgement, FEAD gives due
consideration to the biological data collected during the species
specific analysis, the additional information to help characterize the
potential for exposure (see section VI.D) and other exposure and
toxicity data and lines of evidence used in the screening level
assessment.

Available information on incidents, sales and use of the pesticide,
local use practices, and monitored levels in the environment are
reviewed  (see Sections VI. D. 5 - 8, above).  These factors are used in
combination, and in conjunction with the degree to which the LOCs were
exceeded, to determine whether the predicted effect based on labeled use
of the product, is likely to occur or not. 

1.  Incident Information tc \l3 "1.  Incident Information 

It is acknowledged that not every incident is documented and reported. 
However, a review of incident information for a particular species or
for species of the same taxa that occur in proximity to the listed
species can provide insight to whether the effect predicted is more or
less likely to occur.  For example, if a number of incidents were
reported that the pesticide in question had drifted off site and damaged
non-target non-listed plants, listed plants in the vicinity may also be
at risk of harm. 

2.  Sales and Use of the Pesticide tc \l3 "2.  Sales and Use of the
Pesticide  

Use of a particular pesticide may change and thus, a reliable
distinction between a pesticide use that “may affect” and one that
has no effect on a species cannot be made based on sales and use
information.  However, sales and use information over several past years
can be used to weigh whether a predicted effect is more or less likely. 
For example, there may be 100,000 acres of a particular commodity grown
in the vicinity of a listed species of concern.  If the risk assessment,
which resulted in a determination that the LOC was exceeded, was based
on information that 100% of the crop was treated with the pesticide, but
sales and use information combined with acres grown indicates that only
20% of the 100,000 acres is generally treated with the pesticide,
concentrations in the environment may be less than modeled values.  

3.  Local Use Practices tc \l3 "3.  Local Use Practices  

Similarly, local use practices can be used to predict whether
concentrations in the environment may be less than predicted through
modeling.  For example, if inputs to the model were based on highest
legal application rates and maximum number of applications per season
with the minimum legal interval between application, environmental
concentrations could be predicted to be relatively lower than modeled if
local practices were to treat only half as many times as permitted or at
less than the maximum legal application rate.  

4.  Monitored Levels in the Environment tc \l3 "4.  Monitored Levels in
the Environment  

Most monitoring data available is from programs or studies designed for
various purposes, often not for the purpose of determining the levels to
which a species may be exposed.  These data may underestimate exposure
or overestimate exposure depending on a variety of factors, including
the timing of sampling relative to pesticide use, the frequency of
sampling and the analytical method used to determine the level of
pesticide in the samples.  For these reasons, monitoring data is not
generally used to distinguish between a “no effect” determination
and a “may affect” determination.  However, it can be useful in
weighing whether a predicted effect is more or less likely than would be
indicated by modeling, when viewed in combination with the other factors
mentioned in 1-3 above.  

  	Considering this information, and the degree to which LOC’s were
exceeded in the screening-level risk assessment, FEAD determines that
the pesticide is “may adversely affect” the listed species or that
it “may affect but is not likely to adversely affect” the listed
species. 

G.  Assumptions tc \l2 "G.  Assumptions 

Absent information to the contrary, FEAD makes some assumptions during
its species-specific or habitat-specific assessment as indicated below: 

Where a pesticide is designed for a particular group of insects, others
are not likely to be affected.  Examples include specific strains of
Bacillus thuringensis (BT) which are bred for certain pests.  

The nature of the use itself can preclude exposure in some situations. 
For example, baits will not affect flying insects; fumigants will not
expose species that are not in treated burrows or fields.  

An herbicide that affects only broad-leafed plants will not have an
effect on listed grasses, and an herbicide specific to grasses will not
affect broad-leafed plants.  In a few cases, this kind of distinction
can be made for dicots and monocots, although often there is
insufficient information to address monocots that are not grasses, which
includes lilies, orchids, irises, onions, or sedges.

Listed plants do not occur in cultivated fields.  EPA acknowledges that
they can get to such fields, and even germinate there.  But the
cultivation will not allow the plant to continue to exist there even in
the absence of pesticide use. Therefore, the assumption is made that any
effects to listed plants occur outside the treated field. 		

A pond species or a species in first order streams is assumed to be
represented for acute risk by the typical farm pond model. A species in
a lake can be represented by a farm pond scenario as it may be adjusted
for the larger size of the lake; but then it should also be adjusted,
without quantitative models, for the mixing zone near the pesticide
input to the lake.

A species in 2nd or 3rd order streams is not represented by any current
scenarios and thus, best professional judgment is applied to the result
of models used for 1st order stream species. 

In examining food for listed fish, food will be aquatic arthropods, and
the aquatic arthropod LC50 will be used for the most sensitive species
unless (1) this appears to be far lower than the array of other aquatic
invertebrate LC50s, and (2) the outlier species is not specifically
important to the fish under consideration.

For cover for fish, the EC50 for duckweed (Lemna sp.) is used and in the
absence of any available data on duckweed, algae data are used.  This
assumption is based on the position that algae and duckweed are in
different kingdoms, and as such duckweed is preferred over algae data to
represent vascular plants.  Should aquatic algae become listed, algae
data rather than Lemna data would be used to represent the listed algae.

These assumptions would be used if information to the contrary was not
available.

H.  Environmental Baseline and Analysis of Cumulative Effects tc \l2 "H.
 Environmental Baseline and Analysis of Cumulative Effects 

For those actions that FEAD determines may affect listed species or may
destroy or adversely modify critical habitat, (but for which FEAD cannot
conclude the action is not likely to adversely affect such species or
habitats), FEAD will contact the appropriate Service(s) and request
information relating to the environmental baseline.  Using the
information the Services provide, FEAD will consider how the anticipated
potential effects of the pesticide use are likely to impact the species
or habitat and will include any additional relevant information from the
Service’s environmental baseline in its refined risk assessment.  If
EPA submits a request for formal consultation to the Service, the
supporting materials will include the information on the environmental
baseline provided by the Services.

In addition, if EPA submits a request for consultation to the Service
for which it cannot conclude that the action is not likely to adversely
affect listed species,  FEAD will also include in its supporting
materials an evaluation of the combined impacts of the use of the
pesticide and other “cumulative effects.”  “Cumulative effects”
are those effects of future State or private activities, not involving
Federal activities, that are reasonably certain to occur within the
action area of the Federal action subject to consultation.”  Because
the “action area” for a pesticide may vary from relatively small to
very large, FEAD will determine the scope and depth of the cumulative
effects analysis on a case-by-case basis.  Typically, the larger the
action area, the more general the analysis will be.  FEAD’s initial
and primary source of information on the identity of and potential for
cumulative effects will be the listing notice and recovery plan that
identify the major stressors for a species.  As practicable, FEAD may
also consult with local officials who are likely to be knowledgeable
about future activities that could adversely affect the listed species. 

VII.  List of Support Documents tc \l1 "VII.  List of Support Documents
 

#1.	Study Classifications Used by EFED in Data Evaluation Records
(DER’s) dated February 26, 2003.  Draft.

#2.	Pesticide Assessment Guidelines, Subdivision E, Hazard Evaluation:
Wildlife and Aquatic Organisms; EPA-540/9-82-024, October 1982

#3.	Pesticide Assessment Guidelines, Subdivision J, Hazard Evaluation:
Non-target Plants; EPA-540/09-82-020, October 1982

#4.	Pesticide Assessment Guidelines, Subdivision L, Hazard Evaluation:
Non-target Insects; EPA-540/9-82-019, October 1982

#5.	Pesticide Assessment Guidelines, Subdivision N, Chemistry:
Environmental Fate; EPA-540/9-82-021, October 1982

#6.	Deleted.

#7.  	Guidelines for Ecological Risk Assessment.  Risk Assessment Forum.
 EPA/630/R-95/002F, April 1998.

#8.	Hazard Evaluation Division.  Standard Evaluation Procedure. 
Ecological Risk Assessment.  EPA-540/9-85-001, June 1986.

#9.  	US EPA OPP EFED Guidance for Selecting Input Parameters in
Modeling the Environmental Fate and Transport of Pesticides.  Version
II. February 28, 2002.

#10.	PRZM Standard Crop/Location Scenarios, Procedure to Develop and
Approve New Scenarios, and PRZM Turf Modeling Scenarios to Date. 
Memorandum from EFED’s acting Director, February 27, 2002.

#11.	Pesticide Root Zone Model (PRZM) Field and Orchard Crop Scenarios:
Standard Procedures for Conducting Quality Control and Quality
Assurance.

#12.	Policy for Estimating Aqueous Concentrations from Pesticides
Labeled for Use on Rice.  Memorandum from EFED’s Acting Director,
October 29, 2002.

#13.  	Mammalian Risk Assessments.  February 23, 1995 Draft.

#14	Hoerger, F. and E.E. Kenaga.  “Pesticide Residues on Plants:
Correlation of Representative Data as a Basis for Estimation of Their
Magnitude in the Environment”.

#15.	J.S. Fletcher, J.E. Nellessen and T.G. Pfleeger.  1994.  Literature
Review and Evaluation of the EPA Food-Chain (Kenaga) Nomogram, an
Instrument for Estimating Pesticide Residues on Plants.  Environ. Tox.
Chem. 13(9): 1383-1391.

#16.	Calculation of Terrestrial EECs.  EFED Policy Memorandum from EFED
Acting Director, August 26, 1999.

#17.  	Documentation for ELL-Fate Version 1.2, July 19, 2001.

#18.	Automation of Environmental Exposure Concentrations (EECs) and
Determinations of Risk Quotients (RQs) for Terrestrial Plants Using
TerrPlant Model, Version 1.0.  EFED Policy Memorandum from EFED Acting
Director, October 16, 2002.

#19.  	Closure on Nontarget Plant Phytotoxicity Policy Issues. 
Memorandum from EEB/EFED Chief, October 21, 1994.

#20.	Comparative Analysis of Acute Avian Risk from Granular Pesticides. 
US EPA OPP, March 1992.

 #21.  	Guidance for Conducting Screening Level Avian Risk Assessment
for Spray Applications of Pesticides.  US EPA OPP, July 7, 2000.

#22.	EIIS.  Documentation for the Ecological Incident Information
System.  EFED Information and Support Branch, EFED, OPP.  August 15,
2002.

#23.	Guidance Document for Conducting Terrestrial Field Studies.  EPA
540/09-88-109, September 1988.

#24.	The Office of Pesticide Programs’ Guidance Document on
Methodology for Determining the Data needed and the Types of Assessments
Necessary to Make FFDCA Section 408 Safety Determinations for Lower
Toxicity Pesticide Chemicals.  OPP US EPA, May 9, 2002.

#25.	Decisions on the Ecological, Fate, and Effects Task Force. 
Memorandum from US EPA Assistant Administrator to Director of US EPA
OPP, October 29, 1992.

#26.	What the LOC is, and How it Should Be Used.  Memorandum from EEB
Chief, June 8, 1994.

#27a.	Format and Risk Characterization.  Additional Guidance for EFED
Risk Assessment Documents.  EFED Standard Operating Procedure.  January
13, 2004.

#28.  	Science Policy Council Handbook.  Risk Characterization.  EPA
100-B-00-002, December 2000.

#29.	US EPA 40 CFR Part 158 Data Requirement Tables.

#30.	Science Policy Council Handbook.  Peer Review.  EPA 100-B-00-001,
December 2000.

#31.	Implementation Paper for the New Paradigm.  Memorandum from OPP
Office Director, August 25, 1993.

#32.	 Pesticide EcoToxicity Database.

#33.	Wildlife Exposure Factors Handbook.  Table of Contents and
Introduction.  

#34.	Pesticide Assessment Guidelines, Subdivision I.  Experimental Use
Permits.

#35.  	Standard Evaluation Procedure. Non-target Plants: Vegetative
Vigor - Tiers 1 and 2.

#36.	Standard Evaluation Procedure.  Non-target Plants: Aquatic Field
Testing - Tier 3.

#37.	Standard Evaluation Procedure.  Non-target Plants: Growth and
Reproduction of Aquatic Plants - Tiers 1 and 2.

#38.	Standard Evaluation Procedure.  Non-target Plants: Seed
Germination/Seedling Emergence - Tiers 1 and 2.

#39.	Standard Evaluation Procedure.  Non-target Plants: Terrestrial
Field Testing - Tier 3.

#40.	Standard Evaluation Procedure.  Non-target Plants: Target Area
Testing.

#41.	Standard Evaluation Procedure.  Terrestrial Field Dissipation.

#42.	Standard Evaluation Procedure.  Soil Photolysis.

#43.	Standard Evaluation Procedure.  Aerobic Soil Metabolism Studies.

#44.	Standard Evaluation Procedure.  Soil Column Leaching Studies.

#45.	Standard Evaluation Procedure.  Acute Toxicity Test for Freshwater
Fish.

#46.  	Standard Evaluation Procedure.  Daphnia Magna Life-Cycle (21-Day
Renewal)Chronic Toxicity Test.

#47.	Standard Evaluation Procedure.  Acute Toxicity Test for Estuarine
and Marine Organisms (Shrimp 96-Hour Acute Toxicity Test).

#48.	Standard Evaluation Procedure.  Estuarine Fish 96-Hour Acute
Toxicity.

#49.	Standard Evaluation Procedure.  Acute Toxicity T4est for Estuarine
and Marine Organisms (Mollusc 96-Hour Flow-Through Shell Deposition
Study).

#50.	Standard Evaluation Procedure.  Fish Early Life-Stage.

#51.  	Technical Guidance Document.  Aquatic Mesocosm Tests to Support
Pesticide Registrations.

#52.	Standard Evaluation Procedure.  Avian Single-Dose Oral LD50.

#53.	Standard Evaluation Procedure.  Avian Dietary LC50 Test.

#54.	Standard Evaluation Procedure. Avian Reproduction Test.

#55.  	Guidance Document for Conducting Terrestrial Field Studies.

#56.	Standard Evaluation Procedure. Honey Bee – Toxicity of Residues
on Foliage.

#57.	Standard Evaluation Procedure. Honey Bee - Acute Contact LD50.

#58.	Standard Evaluation Procedure.  Field Testing for Pollinators.

#59.  	Standard Evaluation Procedure.  Pesticide Spray Drift Evaluation:
Droplet Size Spectrum Test and Drift Field Evaluation Test.

#60.  	Standard Evaluation Procedure.  Anaerobic Soil Metabolism
Studies.

#61.	Standard Evaluation Procedure.  Hydrolysis Studies.

#62.	Standard Evaluation Procedure.  Aqueous Photolysis Studies.

#63.	Standard Evaluation Procedure.  Acute Toxicity Test for Freshwater
Invertebrates.

#64.	Policy Establishing Procedures for Reviewing and Approving New
Science Policy.

#65.	EFED’s Revised Policy Guidance for Section 18's.

#66.	Information on Exposure Modeling Work Group.

#67.   	Atrazine 4L Herbicide Pesticide Label.

#68.	Lorsban - 4E Pesticide Label.

#69.	Use the NOAEC from Aquatic Chronic in Risk Assessment.

#70	Background on the Development of LOCs.

#71b.	Procedure for the Inclusion of Open Literature Searches in
Pesticide Screening Level Risk Assessments for Ecological Effects. 
January 21, 2004.  

#72. 	Section 1.  Database and Documentation Overview.  MED
ECOTOXICOLOGY DATABASE SOP’s.  September 1997.

#73.	ECOTOX.  ECOTOXicology Database System.  Literature Search and
Citation Identification. MED ECOTOXICOLOGY DATABASE SOP’s.  April
2001.  

#74.  	ECOTOX.  ECOTOXicology Database System.  AQUIRE Coding
Guidelines. August 2003.

#75.	ECOTOX Data Entry Procedures (AQUIRE).  MED ECOTOXICOLOGY DATABASE.
 June 2000. 

#76.	ECOTOX.  ECOTOXicology Database System.  Chemical Verification and
Database Entry Procedures (EcoChem). April 2001.

#77.	ECOTOX.  ECOTOXicology Database System.  Taxonomic Name
Verification Procedures (CRITTERS). September 2001.

#78.	Draft. SOP for Metabolism Assessment Review Committee.  July 5,
2002.

#79.	Microbial Sample Case Studies.

#80	European Union Directive 91/414/EEC.

#81.	Memorandum and Attached Procedure - “Pesticide Root Zone Model
(PRZM) Field and Orchard Crop Scenarios: Standard Procedures for
Conducting Quality Control and Quality Assurance.  January 21, 2004.

VIII.  References tc \l1 "VIII.  References 

Akesson, N.B.  1990.  Drift evaluation field tests.  In Evaluation of
drift exposure and environmental fate of pesticide application, report
prepared in compliance with drift contract WM175 between the Florida
department of Environmental Regulation and the University of Florida,
Gainesville.

Baehr, C.H. and C.  Habig.  2000.  Statistical evaluation of the UTAB
database for use in terrestrial nontarget organism risk assessment. 
Presentation at the American Society for testing and Materials (ASTM)
Tenth Symposium on Environmental Toxicology and Risk Assessment, April
2000, Toronto, Canada.

Beacham, W.  1994. The Official World Wildlife Fund Guide to Endangered
Species of North 	America.   Vol 4; Beacham Publishing Company,
Washington D.C.  

Dolbeer, K.R., M.L. Avery, M.E. Tobin.  1994.  Assessment of field
hazards to birds from methiocarb applications to fruit crops.  Pesticide
Science 40:147-161.

Driver, C.J., M.W. Ligotke, P. Van Voris, B.D. McVeety, D.B. Brown. 
1991.  Routes of uptake and their relative contribution to the
toxicologic response of northern bobwhite (Colinus virginianus) to an
organophosphate pesticide.  Environmental Toxicology and Chemistry 
10:21-33.

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994.  Literature
review and evaluation of the 	EPA food-chain (Kenaga) nomogram, an
instrument for estimating pesticide residues on plants.  Environmental
Toxicology and Chemistry 13(9):1383-1391.

Fox, G.A. 1991.  Practical causal inference for epidemiologists. J.
Toxicol. Environ. Health 33:359-373.

Hallam, T.G., R.R. Lasiter.  1994.  Individual-based mathematical
modeling approaches in ecotoxicology: a promising direction for aquatic
population and community ecological risk assessment.  In: Wildlife
Toxicology and Population Modeling R.J. Kendall and T.E. Lacher, Jr.,
eds., Lewis Publishers, Boca Raton, FL.

Hill, A.B.  1965.  The environment and disease: association or
causation?  Proc. R. Soc. Med. 58:295-300.

Hakoyama, H., Y. Iwasa, J.  Nakanishi.  2000.  Comparing Risk factors
for population extinction.  Journal of Theoretical Biology 204:327-336.

Kirkwood, J.K.  1983.  A limit to metabolizable energy intake in mammals
and birds.  Comp.  Biochem.  Physiol.  75A:1-3.

Lowe, D.W., J.R. Matthews, C.J. Moseley.  1990.  The Official World
Wildlife Fund Guide to 	Endangered Species of North America.  Vol 1 and
2. Beacham Publishing Company, Washington D.C.: 

Luttik R. and T. Aldenberg.  1997.  Extrapolation factors for small
samples of pesticide toxicity data: specific focus on LD50 values for
birds and mammals.  Environmental Toxicology and Chemistry 16:1785-1788.

Mosely, C.  1992.  The Official World Wildlife Fund Guide to Endangered
Species of North 	America.  Vol 3. Beacham Publishing Company,
Washington D.C.

Nellessen, J.E.,and J.S. Fletcher. 1992.  UTAB: A computer database on
residues of xenobiotic organic chemicals and heavy metals in plants.  J.
 Chem.  Inf.  Comput.  Sci.  32:144-148.

Penman, H.L. 1948.  Natural evaporation from open water, bare soil, and
grass.  Proc.  Royal.  Soc.  London, Series A, 193:120-145.

Pfleeger, T.G., A.  Fong, R.  Hayes, H.  Ratsch, C.  Wickliff.  1996. 
Field evaluation of the EPA (Kenaga) nomogram, a method for estimating
wildlife exposure to pesticide residues on plants.  Environmental
Toxicology and Chemistry 15:535-543.

.

Susser, M. 1986a.  Rules of inference in epidemiology.  Regul. Toxicol.
Pharmacol.  6: 116-128.

Susser, M. 1986b.  The logic of Sir Carl Popper and the practice of
epidemiology.  Am. J. Epidemiol.  124:711-718.

Tanner J.T.  1978.  Guide to the Study of Animal Populations.  The
University of Tennessee Press, Knoxville.

U.S. Department of Health Education and Welfare.  1964.  Smoking and
health: Report of the Advisory Committee to the Surgeon General.  Public
Health Service Publication 1103. Washington, DC: U.S. Department of
Health Education and Welfare.

U.S. Environmental Protection Agency. 1990.  Laboratory Test Methods of
Exposure to

Microbial Pest Control Agents by the Respiratory Route to Nontarget
Avian Species. 

Environmental Research Laboratory, Corvalis, OR.  EPA/600/3-90/070.

U.S. Environmental Protection Agency.  1993.  Wildlife Exposure Factors
Handbook.  EPA/600/R-13/187a, Office of Research and Development,
Washington, DC.

U.S. Environmental Protection Agency.   2002a.  Biological Evaluation on
the CWA 304(a) Aquatic Life Criteria as Part of the National
Consultations Methods Manual.  Draft 12/20/2002.

U.S. Environmental Protection Agency.  2002b.  Eligibility Checklist for
Results of Acute Lethality Tests with Aquatic Animals.  Draft.

U.S. Environmental Protection Agency. 2003.  Environmental Fate and
Effects Division Guidance for Conducting a New Chemical Screen. 
Internal Guidance.  Draft.

Appendix A.	Overview of OPP’s Screening-Level Ecological Risk
Assessment Process for Antimicrobial Pesticides

I.  Background tc \l2 "I.  Background 

The Antimicrobials Division (AD) in OPP is responsible for the
registration and reregistration of antimicrobial pesticides. 
Antimicrobial pesticides include those that claim mitigation or control
of bacteria, viruses, fungi, protozoa, algae, slime, and most recently
prions.  Antimicrobial products used in or on humans or animals are
considered drugs and are approved and regulated by the Food and Drug
Administration (FDA).  The AD regulates antimicrobial pesticides used on
or in inanimate objects, such as wood, floors, and walls; industrial
processes or systems; on surfaces, in water or other liquids to prevent
or reduce contamination, fouling, or deterioration.  

AD reviews data submitted by registrants and conducts screening-level
risk assessments using the basic process outlined for EFED.  These
assessments are conducted  for individual pesticide active ingredients,
formulations, and degradates to evaluate the ecological risk of
antimicrobial pesticides to non-target species, including the potential
impact on listed species.  Formulated product and/or degradate tests are
conditionally required for terrestrial and aquatic animal species, and
aquatic plants using the same approach used by EFED.  Formulated product
tests are always required for terrestrial plant studies, and special
leaching studies. 

In addition to the data required under FIFRA, AD uses open literature
data routinely. A great deal of literature is available for both the
pesticide and non-pesticidal uses of these chemicals and is considered
during the assessment process.  Searches are conducted by a contractor.

AD also reviews human health data that can be useful for predictions of
adverse effects to mammalian wildlife, information on pesticide residue
dissipation in food crops and animal feed items, and leach rate data
from treated objects.  These data can be used to estimate dissipation
half-lives for long term exposure scenarios.

II.  Ecological Effects Testing tc \l2 "II.  Ecological Effects Testing 

AD’s current practice is similar to EFED’s assessment process
described in Section V and uses a tiered system of ecological effects
testing to assess the potential risks of proposed pesticide uses to
non-target plants (§158.540 of the current regulatory text), aquatic
and terrestrial vertebrates and invertebrates (§158.490), and nontarget
insects (§158.590).  These tests include short-term acute, subacute,
reproduction, and field studies, which progress from the basic
laboratory tests to the applied field tests.  The results of each set of
tests must be evaluated to determine the potential of the pesticide to
cause adverse effects and to determine whether further testing is
required.  These data requirements provide the Agency with ecological
effects information and allow the Agency to determine if registration is
appropriate and if precautionary label statements concerning toxicity or
potential adverse effects to nontarget organisms are necessary.

A.  Antimicrobial Pesticide Categories tc \l3 "A.  Antimicrobial
Pesticide Categories 

Antimicrobial pesticides currently fall within one of the following 12
categories:

Agricultural premises and equipment, such as animal houses/pens/milk
houses; 

Food handling/storage establishments premises and equipment, such as
food storage areas, processing plants, restaurants, transport vehicles;

Commercial, institutional and industrial premises and equipment, such as
hotels, theaters;

Residential and public access premises, such as homes, shelters, public
buildings;

Medical premises and equipment, such as medical related facilities -
clinics, hospitals;

Human drinking water systems, such as public/private/emergency water
systems;

Materials preservatives, indoor food/feed, indoor non-food/feed,
indoor/outdoor non-food/feed;

Industrial processes and water systems, such as cooling towers,
pulp/paper mills;

Antifoulants, such as boat bottoms, crab/lobster pots, underwater
structures;

Wood preservatives, such as freshly cut logs, utility poles, fence
posts, railroad ties;

Swimming pools, such as swimming pools, jacuzzis, hot tubs; and

Aquatic areas, such as lakes, streams, drainage ditches, ponds.

B.  Use Categories with Minimal Expected Environmental Exposure tc \l3
"B.  Use Categories with Minimal Expected Environmental Exposure 

Of the 12 antimicrobial use categories, eight are indoor and related
uses: agricultural premises and equipment; food handling and storage
establishments, premises and equipment; commercial, institutional and
industrial premises and equipment; residential and public access
premises; medical premises and equipment; human drinking water systems;
materials preservatives; and swimming pools.  

Movement of antimicrobials from these indoor uses into the general
environment is most likely to occur through water and moves from
rinsates and flushes to effluent water to the aquatic environment.  The
Agency believes that environmental exposures from these uses are likely
to be small for one or more of the following reasons:

These uses are not rapidly or directly connected to aquatic
environments.

Antimicrobials tend to be degraded or bound in the presence of
biological matter.

In some cases effluents are processed in water treatment plants.

Therefore, AD believes these uses pose little prospect of significant
environmental exposure to non-target terrestrial and aquatic organisms

Given the low prospect of significant environmental exposure from this
group of uses, AD requests only a small set of ecological effects and
environmental fate data for these use scenarios.  The data requirements
are avian acute oral LD50 (Guideline 850.2100), an acute freshwater fish
LC50 (Guideline 850.1750), an acute freshwater invertebrates EC50
(Guideline 850.1010), and a hydrolysis study (Guideline 832.2120). 
These studies characterize hazard to target species for label hazard
statements and if an unexpected spill were to occur. AD may request the
testing of additional species or higher tier testing based on the
results of this basic set of studies or reports of adverse effects in
the literature or via FIFRA 6(a)(2).

C.  Use Categories with Significant Expected Environmental Exposure tc
\l3 "C.  Use Categories with Significant Expected Environmental Exposure

The remaining four use categories are industrial processes and water
systems (once-through and all others), antifoulants, aquatic areas, and
wood preservatives.  (Only once-through systems directly introduce the
antimicrobial into the environment in effluent.  Recirculating
industrial processes and water systems, in which the antimicrobial is
re-circulated in the treated system or is disposed of as a hazardous
waste, do not result in direct discharge of antimicrobial pesticide into
the environment.)  These uses either occur outdoors, discharge effluent
directly to the outdoors or result in materials treated with
antimicrobials (i.e. wood preservatives and antifoulants) being placed
in the environment, thereby leading to potentially significant
environmental exposure.  AD utilizes the same battery of ecotoxicity and
environmental fate studies requested by the EFED for agricultural sites.
 In addition, AD requests product leach rate tests (antifoulant paints,
wood preservatives), when appropriate.

III.  Ecological Effects Assessment tc \l2 "III.  Ecological Effects
Assessment  

A.  Exposure Assessment tc \l3 "A.  Exposure Assessment 

Field residue monitoring studies, when available, are used to estimate
EEC’s.  These additional, higher-tiered studies (e.g., avian, fish,
and invertebrate reproduction studies, sediment toxicity studies,
aquatic field studies) may be required when basic data and environmental
conditions suggest possible adverse effects, in order to determine
whether the pesticide meets the requirements for registration and to
determine the need for mitigation. Data from these studies are used to
estimate the potential for chronic effects, taking into account the
measured or estimated residues in the environment. 

In some cases, the results of field studies may give rise to the need
for further testing and/or field residue monitoring.  Field residue
monitoring may be requested of the registrant in lieu of higher tier
biological field studies (Support Document # 7 and #25).  The Agency
makes this determination on a case-by-case basis, considering such
information as the pesticide’s intended use, use rates, toxicity,
physical and chemical properties; the parent compound’s environmental
fate characteristics and transformation products (such as metabolites
and degradation products); nontarget organisms likely to be exposed; and
the likelihood of exposure. 

When field residue monitoring data are not available, models are used to
estimate EEC’s.  The models account for dosage per unit area,
half-lives of the chemical in soil and water, soil
adsorption/desorption, leaching rate, and other factors.   AD generally
uses the fate models used by the EFED and occasionally uses
Luttik-Johnson for antifoulant paints.  In addition, AD is  assessing
additional models for antifouling and for large scale runoff scenarios. 
 AD is currently participating on workgroups formed by the Organization
for Economic Cooperation and Development that are evaluating the various
models available for antifouling paints, wood preservatives, and cooling
towers.

B.  Toxicity Assessment tc \l3 "B.  Toxicity Assessment 

AD generally only requires toxicity data for antimicrobial pesticides
expected to have high exposure.  For pesticides with low exposure based
on labeled uses or other information, AD has adopted an approach that
should allow registrants to generate fewer toxicity studies in total
than those required for high exposure uses.  Under this approach,
registrants of low exposure antimicrobials may perform tests in a tiered
fashion.  After initially required tests are conducted, additional
testing may be required for low-exposure uses if the result of the
initial tests trigger the need for additional data.  

High exposure uses include human or animal drinking water, fruit and
vegetable rinses, egg washes, metal cutting (metalworking) fluids,
swimming pools, outdoor aquatic uses in lakes, rivers or streams which
have the potential to contaminate potable water, indirect food uses with
residues >200 parts per billion (ppb), and any other uses not already
specified which require a tolerance or exemption from the requirement
for a tolerance. Low exposure uses consist of all other uses, which are
expected to pose little or no exposure.  

An antimicrobial use is considered an indirect food use when it is not
applied directly to food, but is used in such a way that food may
reasonably be expected to bear inadvertent residues through contact with
treated surfaces and articles.  Examples of antimicrobial uses which may
result in inadvertent residues in food through normal use are sanitizers
and disinfectants, which may be used in food handling areas.  

C.  Risk Assessment Methods and LOCs tc \l3 "C.  Risk Assessment Methods
and LOCs 

The risk assessment methods used to evaluate potential risk are similar
to those used by the EFED and are based on the RQ, which is compared to
AD’s LOCs.  The LOCs currently address the following risk presumption
categories: 

(1) Acute high - Potential for acute risk is high, and regulatory action
may be warranted in addition to restricted use classification; 

(2) Acute Restricted Use - Potential for acute risk is high, but this
may be mitigated through restricted use classification; 

(3) Acute Listed Species - Potential for acute risk to listed species is
high, and regulatory action may be warranted, and 

(4) Chronic Risk - Potential for chronic risk is high, and regulatory
action may be warranted.   

AD does not perform assessments for chronic risk to plants, acute or
chronic risks to nontarget insects, or chronic risk from granular/bait
formulations to mammalian or avian species.

The ecotoxicity test values (i.e., measurement endpoints) used in the
acute and chronic risk quotients are derived from the results of
required studies.  Examples of ecotoxicity values derived from the
results of short-term laboratory studies that assess acute effects are: 

LC50 - fish and birds,

LD50 - birds and mammals,

EC50 - aquatic plants and aquatic invertebrates, and 

EC25 - terrestrial plants.  

Examples of toxicity test effect levels derived from the results of
long-term laboratory studies that assess chronic effects are: 

LOEC - birds, fish, and aquatic invertebrates,

NOEC - birds, fish and aquatic invertebrates,  and 

MATC - fish and aquatic invertebrates.  

For birds and mammals, the NOEC value is used as the ecotoxicity test
value in assessing chronic effects.  Other values may be used when
justified.  Generally, the MATC (defined as the geometric mean of the
NOEC and LOEC) is used as the ecotoxicity test value in assessing
chronic effects to fish and aquatic invertebrates.  However, the NOEC is
used if the measurement endpoint is production of offspring or survival.

Risk presumptions, along with the corresponding RQs and LOCs are
summarized in Table 1.  



Table 1.  Risk Presumptions for Terrestrial Species

Risk Presumption	

RQ	

LOC

Birds and Wild Mammals

Acute High Risk	

EEC1/LC50 or LD50/sqft2 or LD50/day3	

0.5

Acute Restricted Use	

EEC/LC50 or LD50/sqft or LD50/day (or LD50 < 50 mg/kg)	

0.2

Acute Listed Species	

EEC/LC50 or LD50/sqft or LD50/day 	

0.1

Chronic Risk	

EEC/NOEC	

1

 1  abbreviation for Estimated Environmental Concentration (ppm) on
avian/mammalian food items   

 2    mg/ft2             	3  mg of toxicant consumed/day

   LD50 * wt. of bird             	LD50 * wt. of bird  

 

Risk Presumptions for Aquatic Animals

Risk Presumption	

RQ 	

LOC

Acute High Risk	

EEC1/LC50 or EC50	

0.5

Acute Restricted Use	

EEC/LC50 or EC50	

0.1

Acute Listed Species	

EEC/LC50 or EC50	

0.05

Chronic Risk	

EEC/MATC or NOEC	

1

 1  EEC = (ppm or ppb) in water

Risk Presumptions for Plants	

	

Risk Presumption	

RQ	

LOC

Terrestrial and Semi-Aquatic Plants 

 tc \l2 "Terrestrial and Semi-Aquatic Plants  

Acute High Risk	

EEC1/EC25	

1

Acute Listed Species	

EEC/EC05 or NOEC	

1

Aquatic Plants

 tc \l2 "Aquatic Plants 

Acute High Risk	

EEC2/EC50	

1

Acute Listed Species	

EEC/EC05 or NOEC 	

1

1  EEC = lbs ai/A 

2  EEC = (ppb/ppm) in water 

IV.  Assessments for Listed Species tc \l2 "IV.  Assessments for Listed
Species 

AD’s registration and reregistration documents contain a section on
listed species.     When LOCs for listed species are exceeded, AD will
note in the document that LOC’s are exceeded.  Listed species
exceeding LOC’ s are tabulated by state/county and assessed for their
proximity to the pesticide.  FEAD is then consulted for further analysis
of the species at risk.   FEAD provides appropriate recommendations for
mitigation/restrictions on use if necessary.  

Appendix B.	Overview of OPP’s Screening-Level Ecological Assessment
Process for Biological Pesticides 

 tc \l1 "Appendix B.	Overview of OPP’s Screening-Level Ecological
Assessment Process for Biological Pesticides  

I.  Background tc \l2 "I.  Background 

The Biopesticides and Pollution Prevention Division (BPPD) was created
for the purpose of bringing safer pesticide products into the
marketplace and to encourage the adoption of these safer, reduced risk
products and related integrated pest management (IPM) practices.  The
safer, reduced risk products that are scientifically reviewed and
registered are known as biological pesticides or biopesticides. 
Biopesticides are distinguished from conventional chemical pesticides by
their unique modes of action, low use volumes, natural occurrence,
generally low to no persistence in the environment, and, for many
biopesticide active ingredients, target species specificity.   

There are three categories of biopesticides:  biochemicals, microbials,
and plant-incorporated protectants (PIPs).  As defined in 40 CFR
§158.65 (a) and (b), Biochemical Pesticides include, but are not
limited to compounds such as semiochemicals, natural plant and insect
hormones and synthetic growth regulators, and enzymes.  Microbial
Pesticides include microorganisms and their toxic metabolites such as
bacteria, fungi, viruses, and protozoans, as well as novel microbes (i.
e. genetically-modified or nonindigenous species).  In 40 CFR §152.3, a
Plant Incorporated Protectant (PIP) is defined as a "pesticidal
substance that is intended to be produced and used in a living plant, or
in the produce thereof, and the genetic material necessary for the
production of such a pesticidal substance.  It also includes any inert
ingredient contained in the plant, or produce thereof."  

The Biochemical Pesticide Branch (BPB) is responsible for the
registration of biochemical pesticides.  Microbial pesticides and PIPs
are the responsibility of the Microbial Pesticides Branch (MPB).  Prior
to registration, the potential for any biological pesticide to cause
adverse effects to non-target organisms, including listed species, and
the environment must be thoroughly investigated.  Due to the unique
nature of these pesticides, slightly different, but generally
complimentary and overlapping approaches, are used by BPB and MPB to
assess the potential risks involved with the use of biochemical and
microbial pesticides and PIPs.  

Section II of this appendix describes the assessment process for
biochemical pesticides, and Section III addresses microbial pesticides
and PIPs.  

II. Non-Target Organism Risk Assessment for Biochemical Pesticides tc
\l2 "II. Non-Target Organism Risk Assessment for Biochemical Pesticides 
 

Before beginning a description of the biochemical pesticide risk
assessment process, it is important to first describe the nature of
biochemical pesticides, how they are distinguished from conventional
chemical pesticides, and their pesticidal  mode of action. 

A.  What are Biochemical Pesticides tc \l3 "A.  What are Biochemical
Pesticides   

A biochemical pesticide is defined by the following two criteria:  

It is a generally naturally-occurring substance (or is structurally
similar and functionally identical to a naturally-occurring substance),
and 

It has a non-toxic mode of action.  

It is important to note that not all biochemicals are
naturally-occurring.  An example of  synthetic substances that meet the
criteria for classification as a biochemical are synthetic Lepidopteran
pheromones, which are structurally and functionally identical to the
naturally occurring pheromones produced by moths and butterflies.

Additionally, the "natural occurrence" of a substance does not
immediately lead to the presumption that it has a non-toxic mode of
action.  An example of a substance in this category would be pyrethrum,
a natural insecticide obtained from certain chrysanthemum flowers that
is known to be a very potent neurotoxin.  This toxic mode of action
would preclude pyrethrum from being classified as a biochemical.  

B.  Non-Toxic Modes of Action: tc \l3 "B.  Non-Toxic Modes of Action:  

There are several non-toxic modes of action whereby biochemicals
accomplish their pesticidal activity. These are grouped according to the
following categories:

Plant and insect growth regulators (PGRs and IGRs)

Semiochemicals 

Pheromones 

Attractants/repellents (including irritants)

Suffocating agents

Desiccants

Coatings

Systemic Acquired Response (SAR)-inducers

Biochemical PGRs and IGRs include those substances that mimic or block
the activity of naturally-occurring growth substances.  Pheromones are
be used as either mating disruptants or as attractants to lure target
pests (usually insects) into traps.  Attractants and repellents
encompass all those substances generally considered to be non-pheromone
semiochemicals.  Suffocating agents (typically oils) act by physically
preventing respiration of the target pest, resulting in death by
asphyxiation.  Desiccants accomplish their activity by solubilizing or
physically perturbing waxy cuticles of plants or insects such that the
organisms succumb to rapid evaporative water loss.  Coatings are
substances commonly found in the environment (e.g. clay particles), and
have a passive mode of action (i.e. there is no biochemical interaction
against the target pest).  When applied to plant foliage, coatings
function as physical barriers to infections by plant pathogens, cause
unpalatable abrasiveness to phytophagous insects, or act as physical
irritants.  Substances that induce the SAR response have no direct
activity against the target pest, but function to enhance the inherent
capacity of plants to resist infection by plant pathogens, or produce
secondary plant metabolites that cause the plant to be unpalatable, or
possibly toxic to a pest (e. g. increase phenolic content). 

Although biochemical pesticides, by definition, act via a non-toxic mode
of action, they can still be lethal to the target pest.  Due to the
broad-spectrum, non-species-specific activity of many biochemical
pesticides, all unintentional exposure pathways and potential lethality
to non-targets must be assessed.  Furthermore, a non-toxic mode of
action against the target pest does not presume a lack of toxicity to
non-target organisms.  The following discussion will focus on the
detailed information that are required by reviewers to conduct an risk
assessment.	

C.  Characterization of the Risk tc \l3 "C.  Characterization of the
Risk 

Risks to non-target organisms are characterized via a preliminary
assessment of toxicity (or lethality) and of all conceivable exposure
pathways to non-targets by application of the biochemical pesticide. 
The risk characterization is summarized in the following equation:

Toxicity (or Lethality) x Exposure = Risk

Due to non-toxic modes of action and/or lack of exposure to non-targets
by most biochemical pesticides, a Risk Quotient (RQ) is not typically
calculated since the point estimates of either toxicity and/or exposure
will usually be at or near zero.  A qualitative assessment is conducted,
which is discussed in the next section.

D.  Components of the Risk Assessment tc \l3 "D.  Components of the Risk
Assessment   

The preliminary assessment of toxicity is facilitated by a complete
understanding of the product chemistry of the biochemical active
ingredient and by the use pattern of the end-use product.  These
data/information include (but are not limited to):

Mode of action;

Persistence/degradation rate;

Environmental fate (what are the degradation products and where do they
go);

Product formulation (is it a liquid, granular, or dust);

Application method (e.g. foliar, soil, or fog applications; seed
treatments);

Application rate and timing (amount per unit area;, applications/growing
season; early, mid-, and/or late season applications);

Use sites (terrestrial or aquatic; agricultural, natural area, or
urban/homeowner); and

Target pest(s).

Other data/information may be required on a case-by-case basis,
depending on the nature of the active ingredient and the use sites
proposed for the product.  The risk assessor also must have an in-depth
understanding of the chemistry of the formulated product, particularly
of the "other" (formerly known as inert) ingredients (buffers, diluents,
stabilizers, surfactants, etc.) that are applied with the end-use
product.  These intentionally added ingredients may have unanticipated
adverse effects to non-targets and the environment.  

E.  Risk Assessment for Listed Species tc \l3 "E.  Risk Assessment for
Listed Species 

Potential risks to all non-target organisms are considered when
evaluating a biochemical pesticide and, therefore, specific risk
assessments for listed species are usually not conducted.  As it will be
discussed in more detail below, registrants are required to present
studies, data, and/or information demonstrating a lack of  toxicity
and/or exposure to any non-target species (avian, fish, aquatic
invertebrate, insect, and plant) via the use of a biochemical pesticide
end-use product according to its proposed label directions.  The unique
characteristics of biochemical pesticides, which generally have
non-toxic modes of action, low use volumes, and ready biodegradability
(low to no persistence), usually minimize the risks to all non-targets,
including listed species.  

If the BPB risk assessor, upon review of the product label use
directions and use sites, determines that there is a potential for
exposure to non-target organisms, the registrant will be required to
revise the product label language to ensure that the potential exposure
to non-targets will be mitigated.  These revisions may include, but are
not limited to, changes in application timing and/or deletion of
selected use sites.  When the biochemical has a broad spectrum
(non-specific) and lethal (but non-toxic) mode of action, revisions to
product label use directions, use sites, and environmental hazards
statements may also be required.  An example of a lethal, but non-toxic
model of action is a suffocating oil, such as soybean oil.

Most biochemicals are registered for use in agriculture and
horticultural/ornamental sites, and to a lesser extent in public
recreation areas (e.g., golf courses, city/county parks, etc),
railroad/highway/electrical rights-of-way, and homeowner settings.  If a
listed species is expected to be exposed from a pesticide on a labeled
use site, the risk assessor will consult with FEAD to determine whether
the proposed use of a biochemical pesticide will result in exposure to
listed species.  If it is determined that exposure will occur and that
such exposure has the potential for adverse effects, BPPD and FEAD will
arrange for a consultation with the appropriate agency (U.S. Fish and
Wildlife Service and/or U.S. National Marine Fisheries Service). 
Potential exposure will be minimized as previously described by
evaluating the product label and requiring revisions to the label
language and, if necessary, restricting and/or deleting certain use
sites.

Similarly, if biochemical pesticides are intended for use in natural
areas (nature preserves, state parks, national forests, etc.) or if
there is a potential for off-site movement to such areas, the products
will be evaluated on a case-by-case basis, as described above, to
determine exposure to listed species and other non-target organisms. 
Exposure is not considered to be a problem if the registrant can
unequivocally demonstrate (via EPA-guideline studies or publically
available technical data) that the biochemical pesticide is non-toxic to
all potentially exposed non-target organisms, including listed species,
or that it will not significantly and permanently disrupt the normal
biological activities of potentially exposed non-targets.

It is important to note that most biochemical pesticide active
ingredients are already present in the environment and that non-target
organisms are already regularly exposed to these substances. 
Furthermore, the amount of biochemical active ingredient applied is
often less than what is present in the environment.  It should also be
noted that other governmental agencies (state, local, and/or federal)
that have land management responsibilities may provide additional
site-based assessments to determine whether they will use a particular
biochemical pesticide to control pests and protect listed species.

F.  The Biochemical Risk Assessment tc \l3 "F.  The Biochemical Risk
Assessment   

Once the components of the risk assessment have been assembled, the risk
assessor uses this information to assess the full range of potential and
actual exposure pathways of a biochemical pesticide to non-target
organisms and the environment.  Toxicity (or lethality) data for the
toxicity component of the risk equation are typically obtained from the
tiered guideline studies conducted and submitted by the registrant to
support a registration.  A list of non-target organism study
requirements for biochemicals, arranged as Tiers I, II, and III, is
presented in a table in 40 CFR §158.690 (d).  The tiered study
guidelines are summarized below:  

Tier I	

Tier II	

Tier III

Avian Acute Oral Toxicity	

Volatility	

Terrestrial Wildlife Testing

Avian Dietary Toxicity	

Leaching	

Aquatic Animal Testing

Freshwater Fish LC50	

Adsorption/Desorption	

Non-Target Plant Studies

Freshwater Invertebrate LC50	

Octanol/Water Part. Coeff.	

Non-Target Insect Studies

Non-Target Plant Studies	

UV Absorption	

Non-Target Insect Studies	

Aerobic Soil Metabolism	

	

Aerobic Aquatic Metabolism	

	

Soil Photolysis	

	

Aquatic Photolysis	

Tier I guideline studies are basically acute toxicity studies designed
to determine acute, short-term effects of pesticide exposure to
non-target organisms.  The need for Tier II and Tier III studies are
triggered only when one or more Tier I studies demonstrate significant
adverse effects to non-targets.  Tier II studies are environmental fate
studies that provide additional information on the degradation and
persistence of biochemical pesticides and the potential for
subchronic/chronic exposure.  Tier III studies are longer term and more
rigorous non-target studies on terrestrial and aquatic organisms and
will be needed especially if the active ingredient is shown to persist
in the environment.  

It is important to note that no biochemical active ingredient or product
has yet triggered a requirement for Tier II or Tier III non-target
organism and ecological fate/effects studies.  

Once the exposure pathways to non-target organisms have been determined
and the potential for toxicity (or lethality) to non-target organisms is
understood, a risk assessment is conducted that incorporates all
exposure, toxicity, target pest, and use pattern information. 

Upon completion of the risk assessment, the biochemical pesticide is
subjected to a risk management analysis.  This is generally conducted by
the Regulatory Action Leader (or RAL) for the product, in close
consultation with the science reviewer(s).  The RAL is the principal
point of contact with the registrant of a particular product and is
responsible for administratively guiding the product through the
registration process.  

G.  Risk Assessments for Straight-Chain Lepidopteran Pheromones (SCLPs
tc \l3 "G.  Risk Assessments for Straight-Chain Lepidopteran Pheromones
(SCLPs )  

Non-target organism risk assessments are not typically conducted for
products containing straight-chain lepidopteran pheromones (SCLPs). 
SCLPs are a group of pheromones consisting of unbranched aliphatics
having a chain of nine to eighteen carbons, containing up to three
double bonds, ending in an alcohol, acetate or aldehyde functional group
(40 CFR ???).  This structural definition encompasses the majority of
known pheromones produced by insects in the order Lepidoptera, which
includes butterflies and moths.  Based on the data available to the
Agency (Federal Register Notice 1/26/94 & OECD, 2000), adverse effects
on nontarget organisms are not expected from the use of SCLPs because
these pheromones are released in very small quantities in the
environment and act on a select group of insects (i.e.,
species-specific).  SCLPs are biodegradable by enzyme systems present in
most living organisms, and should present no problems with their normal
physiology. For example, the known metabolism of long-chain fatty acids
predicts that SCLPs would be metabolized either by (-oxidation yielding
a series of paired carbon losses or by complexing with glucuronide and
excretion by the kidneys (Federal Register v.60, Aug.30/95).

H.  Waiver Requests tc \l3 "H.  Waiver Requests   

Submission of guideline studies is the most unambiguous approach to
satisfy the data requirements for registration.  The guideline studies
are designed to provide the BPB risk assessor with the necessary
information to assess the risks posed by a biochemical pesticide when it
is used according to its proposed label directions.  However, there may
be circumstances where the registrant believes that conducting a study
to support a particular data requirement is unnecessary, or may be too
costly to conduct.  The registrant may then request a waiver from the
requirement for conducting one or more guideline studies.  

Study waiver requests must be addressed on a guideline-by-guideline
basis for all Tier I data requirements.  Each waiver request must be
accompanied by a scientific rationale, including technical
information/data, that credibly supports the waiver request and will
assure the BPB risk assessor that a guideline study will not be needed
to complete the risk assessment.  

Data from non-guideline studies are acceptable on a case-by-case basis
only if they provide information/data that is equivalent to
information/data that would have been generated by guideline studies,
and they are conducted according to generally accepted scientific
principles.  Non-guideline studies obtained from the open technical
literature, which is routinely searched,  must have a reasonably
complete description of the materials and methods to assure the BPB risk
assessor that the submitted data will be useful in completing the risk
assessment.  Journal abstracts and reports from technical meeting
proceedings generally do not contain sufficient information and,
therefore, are typically classified as unacceptable for use in risk
assessments.  Similarly, testimonials found in advertising literature
and anecdotal information unsupported by credible data are also
unacceptable.

Another approach to supporting waiver requests is to demonstrate that
there will be no exposure of non-target organisms (either directly or
indirectly) to the biochemical pesticide following application to the
proposed use site(s) and target pest(s) listed on the product label. 
For example, if the registrant request waivers from the study data
requirements for fish toxicity and aquatic invertebrate toxicity, it
must be demonstrated that the product is intended solely for terrestrial
uses and that it is highly unlikely that fish or aquatic invertebrates
would be exposed to the biochemical pesticide directly or indirectly
(via runoff or spray drift).  The product label would also be required
to contain specific language warning the product user to avoid applying
the product on or near aquatic sites and environmental hazards
statements indicating that the product is toxic to fish and aquatic
invertebrates.   Alternatively, the registrant could present data
demonstrating that the active ingredient rapidly degraded to non-toxic
compounds following application, thereby minimizing exposure.  The
"other"  (inert) ingredients in an end-use product must also be
considered when developing a scientific rationale to support a waiver
request.  

I.  Risk Management tc \l3 "I.  Risk Management   

After the risk assessment is completed, the biochemical pesticide is
subjected to a risk management analysis by the RAL for the product, in
close consultation with the science reviewer(s).  If minor risks
regarding toxicity/lethality of the biochemical pesticide are identified
in the risk assessment, the risks may be mitigated by addition of
precautionary statements and environmental hazards statements (see
discussion above under Waiver Requests) on the product label.   

Conversely, if it is determined that risks cannot be mitigated with
restrictive label language, and that severe adverse effects may result
if the product is used as intended, BPPD may recommend that the product
be transferred to the Registration Division where it would be treated as
a conventional chemical pesticide and would receive a higher level of
scrutiny and the reduced data requirements would not apply.  Usually, if
adverse non-target organism and environmental effects are indicated in
the risk assessment it is also likely that there may be analogous
adverse effects to human health.  

    

J.  Guidance for Non-Target Organism, Fate, and Expression Data
Requirements tc \l3 "J.  Guidance for Non-Target Organism, Fate, and
Expression Data Requirements    

For biochemical pesticides, guidance for all non-target organism, fate,
and expression data requirements may be found in the following Subpart
D, Data Requirement Tables:  40 CFR §158.202 and in 40 CFR §158.690
(d).  Specific information on individual non-target organism, fate, and
expression testing guidelines is located in the OPPTS Harmonized
Guidelines Series 850 and Series 835, and may be accessed in
downloadable format at the U.S. EPA website at: 

www.epa.gov/docs/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines
/Series

and

www.epa.gov/OPPTS_Harmonized/835_Fate_Transport_and_Transformation_Test_
Guidelines/Series/

Ideally, biochemical pesticides will have little or no effects on
non-target organisms, degrade rapidly in the environment, have low
application rates and are applied when non-targets are least likely to
be present.  

BPPD has registered many products that have broad spectrum effects on
targets and non-targets, that persist in the environment, and/or are
applied at relatively high rates.  These issues are typically managed by
the use of restrictive language (i.e. explicit use directions and
precautionary statements) on the product label.  For example, if a
product has been determined to be a hazard to honey bees or other
pollinators, the registrant will be instructed to have a label statement
that restricts application of the biochemical pesticide at times when
these beneficial non-target insects are present at the use site.  

II. Endangered Species  Risk Assessment for Microbial Pesticides tc \l2
"II. Endangered Species  Risk Assessment for Microbial Pesticides 

A.  Characterization of the Listed Species Risk tc \l3 "A. 
Characterization of the Listed Species Risk   

BPPD must identify all biological pesticides whose use may cause
potential adverse impacts on listed species and their habitats by
determining which flora and fauna may be affected by the proposed
product.  This determination is made by examining the information on
non-target species and host range data of the proposed pesticide. 
Available information on the biology and toxicity of the microbial pest
control agent (MPCA),  non-target effects data submitted for
registration, and the pre-registration host-range studies are used to
identify the non-target plants and wildlife that may be adversely
affected.  The data examined include avian, wild mammal, freshwater,
estuarine and marine plants and wildlife, terrestrial plants and several
orders of insects.  Because of the relative specificity and limited host
range of MPCAs, the listed species most likely to be affected are
usually related to the target pests.  (Five sample case studies are
provided in Support Document #79.)

1.  Exposure Assessment tc \l4 "1.  Exposure Assessment  

The listed species related to the non-target organisms that may be
affected are identified to see if the use patterns of the pesticidal
product will encroach on their habitat.  The U.S. Fish and Wildlife
Service web site (http://endangered.fws.gov/) is consulted for the
identification of listed species and their location by state(s) and
their habitat within the state(s).  Internal EPA documents or search
programs, such as DANGER which identify overlap of  the habitat of
listed species with agricultural crops, may also be used.  If  overlap
of the habitat of listed species and pesticide use sites does not exist,
a “no effect’ finding is made.  (Refer to case study #1, An ES
Assessment for Bacillus thuringiensis Cry 3bb1 Delta Endotoxin in Corn
by Habitat Overlap Evaluation, and case study #2, M.anisopliae for an
example of a case where habitat overlap cannot be determined).

2.  Integration of Exposure and Effects Data Using the RQ tc \l4 "2. 
Integration of Exposure and Effects Data Using the RQ 

 	When the use pattern of a pesticidal MPCA may overlap with the habitat
of any listed species related to a species susceptible to the pesticide,
a risk characterization is performed.  Risk characterization integrates
the results of exposure and toxicity data to evaluate the likelihood of
adverse effects on non-target species.  In this approach, BPPD uses the
RQ method to compare exposure over toxicity. 

For most pesticides, the effects characterization is based on a
deterministic approach using the LC50.  Estimated Environmental
Concentrations (EECs) based on maximum application rates are divided by
acute toxicity (LD50) values.  The methods are based on the procedures
described in Section V and include risk assessment criteria for listed
species.  These species risk endpoints have also been accepted by the
Office of Endangered Species (1980).

A typical risk assessment starts with a determination of the EEC based
on maximum application rates and the LD50 value for a given species. 
The ratio of the EEC and LD50 can then be compared to some relative
quotient ranking to indicate possible acute adverse effects to
non-target organisms.  The criteria for a “may effect” determination
for listed species include the following:  

Acute Risk: Species may be potentially affected by use when the acute RQ
is >0.05 (20-fold safety factor) for aquatic or when the RQ is >0.1
(10-fold safety factor) for terrestrial species.  

Chronic Risk: Species may potentially be affected through chronic
exposure when the chronic RQ > 1 (for all animals).  

Plant risk: Potential for effects in plants (RQ > 1).  

In OPP a safety factor of 5x is applied to the acute RQ for terrestrial
non-endangered organisms.  The more stringent safety margin criteria for
listed species were developed to accommodate uncertainty of a no-effect
level based on the toxicity data available for related non-endangered 
species.  It is impossible to obtain LC50 or LD50 data for listed
species, and thus it must be assumed that the sensitivity of these
species is similar to that of closely related indicator organisms. 

A potential “may effect” risk to listed species can be evaluated by
comparing the toxicity value from the most sensitive species tested  to
a conservative estimate of exposure.  The most conservative approach is
to apply the safety factor (10-fold for terrestrial and 20-fold for
aquatic) to the LC50 or LD50 from the most sensitive species tested to
accommodate uncertainty in the risk assessment process. A safety factor
is desirable to ensure protection of species in which even a single
death is of special concern.  

When the RQ meets or is higher than the safety margins given above,  a
“no effect” finding is made in cases where there may be an overlap
of  species habitat and pesticide use. (Refer to case studies #3 and #4
as examples for an actual application of the RQ method in BPPD).  

If, however, the calculated RQ is less than the level set by the above
criteria, then BPPD presumes that there will be a “may effect” risk
to the  species and BPPD, in cooperation with FEAD, will initiate
consultation with the  FWS.  (Refer to case study #5 for an example of
restrictions placed on B.thuringiensis uses by a FWS consultation.)  

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