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.