Risks of Malathion Use to Federally Listed
California Red-legged Frog
(Rana aurora draytonii)

Pesticide Effects Determination

Environmental Fate and Effects Division
Office of Pesticide Programs
Washington, D.C. 20460

October 19, 2007


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Primary Authors

Edward Odenkirchen, Ph.D., Senior Scientist
Stephen P. Wente, Ph.D., Biologist

Secondary Review

Paige Doelling Brown, Ph.D., Biologist

Nancy Andrews, Ph.D., Branch Chief,
Environmental Risk Assessment Branch 1

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Table of Contents

1.	Executive Summary	1

1.1	Fate Summary	1

1.2	Effects Summary	2

2.	Problem Formulation	9

2.1	Purpose	9

2.2	Scope	11

2.3	Previous Assessments	14

2.4	Malathion Characteristics, Fate, and Transport	14

2.4.1	Chemical Profile	15

2.4.2	Mechanism of Action	15

2.4.3	Malathion Products with Additional Active Ingredients	16

2.4.4	Environmental Fate Assessment	17

2.4.4.1	Degradation	17

2.4.4.2	Metabolism	17

2.4.4.3	Dissipation	20

2.4.4.4	Accumulation in Fish	21

2.4.5	Environmental Transport Summary	21

2.4.6	Degradates and impurities	23

2.4.7	Use Profile	24

2.5	Assessed Species	28

2.6	Action Area	32

2.7	Assessment Endpoints and Measures of Ecological Effect	33

2.8	Risk Assessment Conceptual Model	35

2.8.1	Risk Hypotheses	35

2.8.2	Assessment Diagrams	36

2.9	Analysis Plan	40

2.9.1	Exposure Analysis	40

2.9.2	Effects Analysis	41

2.9.3	Acti on Area Analy si s	42

3.	Exposure (Fate) Assessment	43

3.1	Label Application Rates and Intervals	43

3.1.1	Application Rates	43

3.1.2	Application Timing	54

3.2	Aquatic Exposure Assessment	71

3.2.1	Aquatic Exposure Modeling	72

3.2.1.1	PRZM/EXAMS Inputs	72

3.2.1.2	PRZM Scenarios	74

3.2.1.3	Aquatic Estimated Environmental Concentrations	80

3.2.2	Effect of Application Timing on Aquatic EECs	87

3.2.3	Surface Water Monitoring Data	88

3.2.3.1	Non-targeted Monitoring	89

3.2.3.2	Targeted Monitoring	90

3.2.4	Air Monitoring	97

3.2.5	Aquatic Exposure Summary	98

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3.3 Terrestrial Exposure Assessment	101

3.3.1	Terrestrial Wildlife Exposure Modeling	101

3.3.2	Terrestrial Plant Exposure Modeling	116

4.	Effects Assessment	117

4.1	Evaluation of Aquatic Ecotoxicity Studies	117

4.1.1	Acute Toxicity to Fish and Larval Stage Amphibians	118

4.1.2	Freshwater Fish and Amphibian: Chronic Exposure
(Growth/Reproduction) Studies	122

4.1.3	Freshwater Fish: Sublethal Effects and Additional Open Literature
Information	123

4.1.4	Freshwater Invertebrates: Acute Exposure Studies	124

4.1.5	Freshwater Invertebrates: Chronic Exposure Studies	129

4.1.6	Toxicity to Aquatic Plants	129

4.2	Evaluation of Terrestrial Ecotoxicity Studies	130

4.2.1	Toxicity to Mammals	130

4.2.1.1	Acute and Chronic Mammalian Toxicity	130

4.2.1.2	Mammalian Field Studies	130

4.2.2	Toxicity to Birds	131

4.2.2.1	Acute and Subacute Avian Toxicity	131

4.2.2.2	Chronic Avian Toxicity	132

4.2.2.3	Avian Development and Embryonic Effects Studies	133

4.2.2.4	Avian Sublethal Effects Studies	133

4.2.2.5	Avian Field Studies	134

4.2.3	Effects on Other Terrestrial Vertebrates Including Amphibians	135

4.2.4	Toxicity to Terrestrial Insects and Other Invertebrates	136

4.2.4.1	Laboratory Studies	136

4.2.4.2	Field Observations of Effects to Non-Target Insects	137

4.2.5	Toxicity to Plants	139

4.2.6	Terrestrial Wildlife Field Incidents	139

4.3	Maloxon Toxicity	140

4.3.1	Aquatic Organism Toxicity for Maloxon	140

4.3.2	Terrestrial Organism Toxicity for Maloxon	141

4.3.3	Establishing Relationships between Malathion and Maloxon Toxicity . 141

5.	Risk Characterization	142

5.1 Risk Estimation	142

5.1.1	Aquatic Phase Direct Effects	142

5.1.2	Aquatic Phase Indirect Effects	150

5.1.2.1	Aquatic Phase Indirect Effects via Reduction in Food Items	150

5.1.2.2	Aquatic Phase Indirect Effects via Reduction in Habitat and/or Primary
Productivity (Freshwater Aquatic Plants)	164

5.1.2.3	Aquatic Phase Indirect Effects via Reduction in Terrestrial Plant
Community (Riparian Habitat)	168

5.1.3	Terrestrial Phase Direct Effects	168

5.1.4	Terrestrial Phase Indirect and Effects	176

5.1.4.1 Terrestrial Phase Indirect Effects via Reduction in Food Items	176

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5.1.4.2 Terrestrial Phase Indirect Effects via Reduction in Terrestrial Plant

Community (Riparian Habitat)	193

5.2 Risk Description	193

5.2.1	Direct Effects to the California Red Legged Frog	197

5.2.1.1	Aquatic Phase Direct Effects	197

5.2.1.2	Terrestrial Phase Direct Effects	200

5.2.2	Indirect Effects via Reduction in Food Items	212

5.2.2.1	Aquatic Phase Frog- Fish as Prey	212

5.2.2.2	Aquatic Phase Frog- Invertebrates as Prey	220

5.2.3	Indirect Effects via Reduction in Habitat and/or Primary Productivity
(Freshwater Aquatic Plants)	224

5.2.4	Indirect Effects via Alteration in Terrestrial Plant Community (Riparian
Habitat) 224

5.2.5	Modification to Critical Habitat	224

6.	Uncertainties	228

6.1	Exposure Assessment Uncertainties	228

6.1.1	Modeling Assumptions	228

6.1.2	Application Rate Uncertainty	229

6.1.3	Timing of Malathion Applications	252

6.1.4	Impact of Vegetative Setbacks on Runoff	252

6.1.5	PRZM Modeling inputs and Predicted Aquatic Concentrations	252

6.2	Effects Assessment Uncertainties	254

6.2.1	Age Class and Sensitivity of Effects Thresholds	254

6.2.2	Extrapolation of Effects	254

6.2.3	Acute LOC Assumptions	254

7.	References	255

Appendices

Appendix A Product Formulations Containing Multiple Active Ingredients
Appendix B ECOTOX Studies

Attachments

Attachment 1 Life History of the California Red-Legged Frog
Attachment 2 Baseline Cumulative Effects

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Table of Figures

Figure 1. Total pounds of malathion applied for all uses identified in the California Dept.

of Pesticide Regulation database from 2001 through 2005	26

Figure 2. Comparison of phases of the California Red-legged Frog (CRLF) life cycle to

total malathion usage in California by month for years 2001 through 2005	27

Figure 3. Average percent contribution of counties to total California malathion usage
based on 2002 through 2005 California Dept. of Pesticide Regulation Pesticide Use
Reporting (CDPR PUR) use data (33 counties contributing less than 1% each are not

shown)	28

Figure 4. California Red-legged Frog (CRLF) distribution within the United States	30

Figure 5. Conceptual model for direct malathion effects on the aquatic phase of the
California Red-Legged Frog. Compartments and pathways in dashed lines are considered
possible but not of sufficient significance to warrant quantification in the assessment. ..37
Figure 6. Conceptual model for malathion effects on the terrestrial phase of the California
Red-legged Frog. Compartments and pathways in dashed lines are considered possible

but not of sufficient significance to warrant quantification in the assessment	38

Figure 7. Conceptual model for malathion effects on the aquatic component of California
Red-legged Frog critical habitat. Compartments and pathways in dashed lines are
considered possible but not of sufficient significance to warrant quantification in the

assessment	39

Figure 8. Conceptual model for malathion effects on the terrestrial component of
California Red-legged Frog critical habitat. Compartments and pathways in dashed lines
are considered possible but not of sufficient significance to warrant quantification in the

assessment	40

Figure 9. Variation in malathion application timing across years (left graph) and
generalized within-year application timing (right graph) by crop use according to the
CDPR PUR data. Malathion application period (first to last applications), according to

each scenario, is indicated by dashed black vertical lines (right graph only)	55

Figure 10. Variation in peak (blue) and maximum average 21-day (green) and 60-day
(red) PRZM/EXAM estimated environmental concentrations (EECs) for malathion across
a range of application dates. For comparison, a moving average of the CaDPR daily
application malathion applied to alfalfa (solid black line) and the first and last application

dates used in the PRZM model are shown (vertical dashed lines)	88

Figure 11. Frequency distributions of (a) maximum site malathion concentrations for
California Department of Pesticide Regulation (CaDPR) and (b) U.S. Geological

Survey's National Water Quality Assessment (NAWQA) data sets	90

Figure 12. Comparison of PRZM/EXAMS estimated environmental concentrations
(EECs) to the percentage of EEC contributed from drift shows that many high aquatic
EECs are largely, or almost solely, attributable to drift alone (drift contribution for

individual scenarios is listed in Table 9)	99

Figure 13. Comparison of PRZM/EXAMS estimated environmental concentrations
(EECs) for malathion and maloxon to non-targeted monitoring and targeted monitoring in
agricultural (Boll Weevil Control Program) and urban (Mediterrarainian fruit fly control)
settings. (N.S. = not sampled.)	100

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Figure 14. Comparison of the range of the California Red-legged Frog (CRLF) location
of agricultural lands in California	198

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Table of Tables

Table 1. Summary of effects determinations and the basis for those determinations for the
California Red-legged Frog (CRLF) from malathion and its degradate/impurity maloxon.

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Table 2. Effects determination summary for the critical habitat impact analysis	6

Table 3. Physical/chemical properties of malathion (0,0-dimethyl phosphorodithioate of

diethyl mercaptosuccinate)	15

Table 4. Open literature studies reporting aerobic soil metabolism degradation rates	17

Table 5 Assessment endpoints and measures of ecological effects	33

Table 6. A partial listing21 of applicable labels and maximum aerial (air), home and

Garden (H&G), and non-aerial (other) for each crop/site grouping	44

Table 7. PRZM/EXAMS input parameters for malathion and maloxon	74

Table 8. Characteristics (application rates, number of applications and timing, PRZM
scenario name and meteorological station) of the PRZM/EXAMS scenarios used to

evaluate California Red-legged Frog (CRLF) exposure to malathion	75

Table 9. PRZM/EXAMS estimated environmental concentrations (EECs) for malathion
(estimate includes drift component) and maloxon (drift calculated separately). Maloxon
application rate is assumed to be 10.7% of malathion application rate. Maloxon as an

impurity in drift is assumed to be 0.1% of malathion in drift	81

Table 10. Field monitored runoff a from the Cotton Boll Weevil Control Program	91

Table 11. Southeast Boll Weevil Eradication Program monitoring data of spray drift to

adjacent moving water (USDA 1993)a	92

Table 12. Texas Lower Rio Grande Valley Boll Weevil Eradication Program monitoring

data of spray drift to adjacent moving water (USDA 1995a)a	93

Table 13. Southern Rolling Plains Boll Weevil Eradication Program monitoring data of

spray drift to adjacent moving water (USDA 1994-5)a	93

Table 14. Malathion levels in bodies of water in relation to medfly control sprayinga.... 95
Table 15. Malathion level in 29 ponds in Florida exposed to direct (unprotected aquatic

sites) or indirect (protected aquatic sites) malathion spray in medfly controf	96

Table 16. Malathion and maloxon concentrations in creeks after malathion applications in

the Santa Clara Valley	97

Table 17. Dietary- and dose-based estimated environmental concentrations (EECs) for
small birds and Mammals. Small birds (approximately 20 g) and small mammals

(approximately 15 g) are prey items of the California Red-legged Frog	103

Table 18. Assessment of direct effects on California Red-legged Frog (CRLF) using
dose-based estimated environmental concentrations (EECs) of malathion based on the T-

Herps model for small (1.4 g), medium (37 g), and large (238 g) CRLF	Ill

Table 19. Freshwater fish and amphibian acute toxicity studies (sourced from OPP data

and ECOTOX studies meeting minimum quality for database and OPP)	119

Table 20. Freshwater fish and other aquatic vertebrate chronic exposure toxicity data
(growth, survival, and reproduction endpoints) (sourced from OPP data and ECOTOX

studies meeting minimum quality for database and OPP)	123

Table 21. Freshwater fish and other aquatic vertebrate sublethal effects (sourced from
OPP data and ECOTOX studies meeting minimum quality for database and OPP)	123

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Table 22. Freshwater invertebrate acute toxicity studies (sourced from OPP data and

ECOTOX studies meeting minimum quality for database and OPP)	125

Table 23. Freshwater invertebrate chronic exposure toxicity studies (sourced from OPP

data and ECOTOX studies meeting minimum quality for database and OPP)	129

Table 24. Aquatic plant toxicity studies (sourced from OPP data and ECOTOX studies

meeting minimum quality for database and OPP)	129

Table 25. Mammalian acute oral and chronic dietary toxicity studies	130

Table 26. Avian acute oral toxicity studies (sourced from OPP data and ECOTOX studies

meeting minimum quality for database and OPP)	131

Table 27. Avian Subacute Dietary Toxicity Studies (Sourced from OPP data and

ECOTOX Studies Meeting Minimum Quality for Database and OPP)	131

Table 28. Avian reproduction studies (sourced from OPP data and ECOTOX studies

meeting minimum quality for database and OPP)	132

Table 29. Non-target insect acute contact toxicity studies (sourced from OPP data and

ECOTOX studies meeting minimum quality for database and OPP)	136

Table 30. Incidence reports potentially attributable to malathion	140

Table 31. Aquatic organism maloxon toxicity studies (sourced from ECOTOX studies

meeting minimum quality for database and OPP)	140

Table 32. Within species comparisons of malathion and maloxon acute toxicity	141

Table 33. Levels of concern for terrestrial and aquatic organisms	142

Table 34. Assessment of direct effects on the aquatic phase California Red-legged Frog
(CRLF) from malathion (estimate includes drift component) and maloxon (drift

calculated separately)	143

Table 35. Assessment of indirect effects on the aquatic phase California Red-legged Frog
(CRLF) for malathion (estimate includes drift component) and maloxon (drift calculated

separately) to freshwater fish	151

Table 36. Assessment of indirect effects on the California Red-legged Frog (CRLF)
based on effects of malathion (estimate includes drift component) and maloxon (drift

calculated separately) to freshwater Invertebrates	158

Table 37. Assessment of indirect effects to aquatic phase California Red-legged Frog
(CRLF) based on acute risk to aquatic plants and the PRZM/EXAMS estimated

environmental concentrations (EECs) of malathion	164

Table 38. Assessment of indirect effects on the terrestrial phase of the California Red-
legged Frog (CRLF based on dietary- and dose-based risk quotients (RQs) for small (20

g) birds (a prey item of the CRLF)	169

Table 39. Assessment of indirect effects on the terrestrial phase of the California Red-
legged Frog (CRLF based on dietary- and dose-based risk quotients (RQs) for small (15

g) mammals (a prey item of the CRLF)	178

Table 40. Assessment of indirect effects on the terrestrial phase of the California Red-
legged Frog (CRLF based on dietary- and dose-based risk quotients (RQs) for small (20

g) birds (used as surrogate for CRLF)	186

Table 41. Malathion Effects Determination Summary for the CRLF	194

Table 42. Assessment of direct effects on terrestrial phase California Red-legged Frog
(CRLF) using dietary-based acute and chronic risk quotients (RQs) based on the T-Herps
model estimated environmental concentrations (EECs) for malathion	201

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Table 43. Assessment of direct effects on terrestrial phase California Red-legged Frog
(CRLF) using dose-based acute risk quotients (RQs) based on the T-Herps model

estimated environmental concentrations (EECs) of malathion	207

Table 44. Results of Acute Malathion EECs Compared with Distribution of Fish LC50

Values Adjusted for Acute Non-Listed Species LOC	213

Table 45. Results of Chronic Malathion EECs Compared with a Distribution of Fish

NOAEC Values Adjusted for Acute Non-Listed Species LOC	216

Table 46. Results of Acute Malathion EECs Compared with Distribution of invertebrate

LC50 Values Adjusted for Acute Non-Listed Species LOC	220

Table 47. Effects Determination Summary for the Critical Habitat Impact Analysis.... 224
Table 48. Comparison of maximum application rates from current labels to the maximum
supported Cheminova and IR-4 application rates and the average application rates
calculated from the 2001-2005 CDPR PUR data for each crop/site grouping (all

application rates in lbs ai/A)	231

Table 49. Chronic invertebrate risk quotients (RQs) estimated for Cheminova/TR-4
supported maximum malathion application rates (agricultural uses only) listed by current

label crop/site	239

Table 50. Chronic invertebrate risk quotients (RQs) estimated for the average malathion
application rates calculated from the 2001-2005 CDPR PUR data for each CDPR PUR
crop/site grouping listed by current label crop/site	243

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1. Executive Summary

This ecological risk assessment evaluates the potential for the use of the insecticide
malathion (PC#057701) to affect the California red-legged frog (CRLF) (Rana aurora
draytonii), and/or modify its designated critical habitat. The CRLF was Federally listed
as a threatened species by the U.S. Fish and Wildlife Service (USFWS) effective June 24,
1996 (USFWS 1996). It is one of two subspecies of the red-legged frog and is the largest
native frog in the western United States (USFWS 2002). Final critical habitat for the
CRLF was designated by USFWS on April 13, 2006 (USFWS 2006; 71 FR 19244-
19346). The frog is endemic to California and Baja California (Mexico) and historically
inhabited 46 counties in California, including the Central Valley and both the coastal and
interior mountain ranges (USFWS 1996). Its range has been reduced by approximately
70%, and it currently inhabits 22 counties in California (USFWS 1996). This assessment
is one of a series of ecological risk assessments developed for, and consistent with, the
settlement for the court case Center for Biological Diversity (CBD) us. EPA et al. (Case
No. 02-1580-JSW(JL)).

Malathion is an organophosphate insecticide that has been used in the U.S. since the
1950's. It is currently registered for use on more than 100 food and feed crops as well as
many non-agricultural uses (forestry, mosquito control, nurseries, public health,
residential, rights-of-way, and turf). Though malathion has been manufactured by a
variety of companies, all technical malathion used in the U.S. is marketed and distributed
by Cheminova since 1994.

In agreement with the Reregi strati on Eligibility Document (RED) for malathion (USEPA
2006), this assessment finds that malathion has the potential to adversely impact non-
target biota. The magnitude of these adverse impacts tends to be greater in the current
assessment than those presented in the RED for two reasons. First, the application rates in
the RED are based on an agreement between the U.S. Dept of Agriculture's Inter-
regional Team # 4 (IR-4) and the registrant, Cheminova, to support lower agricultural
application rates, in general, than occurred on malathion labels at the time of that
agreement. Because the current risk assessment is based on current labels, which to a
large extent do not reflect these lower application rates yet, the agricultural application
rates used in the current assessment are higher than in the RED. Second, this assessment
identified many more sensitive endpoints than used in the RED, which lowers the
concentration levels at which adverse affects are assumed to occur.

1.1 Fate Summary

Under many intended use conditions, malathion shows little persistence in the
environment. Based on registrant data and open literature reports, the Environmental Fate
and Effects Division (EFED) of the Office of Pesticide Programs (OPP) concludes that
the primary routes of dissipation of malathion in surface soils appear to be microbially-
mediated soil metabolism and hydrolysis under neutral or basic conditions.

There are some conditions, however, under which malathion is more persistent.
Hydrolysis of malathion is likely to be much slower under acidic conditions.

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Additionally, open literature studies suggest persistence on soil is longer under dry,
sandy, low nitrogen, low carbon, and acidic conditions (Walker and Stojanovic 1973).

Maloxon (also commonly spelled as mak/oxon), which is both an impurity and degradate
of malathion, is the only degradate/impurity of malathion that occurs in sufficient
concentration and has sufficient toxicity to potentially exceed the ecological risk posed
by malathion, itself. Malathion applied to artificial surfaces may be more persistent and
result in higher levels of maloxon production. Under dry and microbially inactive
environmental conditions maloxon concentrations have been found at levels up to 10.7%
of the malathion level applied (CaEPA 1993). Monitoring studies conducted during
medfly control programs in urban areas show high levels of maloxon (> 328 |ig/L) in
runoff water (CaDFG 1982).

Typically in risk assessments, conservative assumptions (over-protective) are
purposefully made to ensure protection of the entity considered (the CRLF in this case).
However, comparisons of model estimated environmental concentrations (EECs) used in
this assessment with available targeted surface water monitoring data show the
conservative assumptions (maximum label application rate used, application to an entire
water body's watershed on a single day, etc.) made in this assessment do not appear to
result in EECs that exceed targeted monitoring measured concentrations. Therefore, the
EECs used in the risk assessment may not be conservative enough to be protective of the
CRLF under all circumstances. The reasons why the EECs modeled for this assessment
appear to under-predict targeted monitoring data are unknown.

1.2 Effects Summary

This risk assessment considers both direct effects of malathion use to the CRLF itself and
indirect effects on the CRLF and its critical habitat. Both the aquatic and upland
(terrestrial) habitat of the CRLF is assessed because the CRLF requires both to complete
its life cycle and the exposure and effects differ between habitat types. The aquatic phase
of the CRLF's life cycle includes eggs, larvae, tadpoles, juveniles, and adults. Although
juveniles and adults spend a significant amount of time in terrestrial habitats, they also
use the aquatic portion of their habitat, especially during breeding. The terrestrial phase
evaluation includes juveniles and adults. Components of the ecosystem addressed in the
assessment include aquatic plants, aquatic invertebrates, fish, terrestrial plants, terrestrial
invertebrates, and terrestrial vertebrates {i.e., small mammals and birds) in addition to the
various life stages of the CRLF itself.

Malathion's mode of action is similar to other organophosphate insecticides in that
malathion, and its degradate/impurity maloxon, inhibit acetyl cholinesterase, an enzyme
critical to the proper functioning of the central nervous system. Not surprisingly,
malathion and maloxon were found to have much greater adverse affects both directly to
the CRLF and its animal prey base than to the vegetative portions of the CRLF's diet and
habitat.

After completing the analysis of the effects of malathion and maloxon on the Federally
listed CRLF in accordance with methods delineated in the Overview Document (USEPA

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2004), EFED concludes that the use of malathion may affect, and is likely to adversely
affect the CRLF, based on direct affects to the CRLF and indirect effects to the prey base
of the CRLF. These effects of the current label uses of malathion insecticide in California
are anticipated to occur or could occur throughout the state of California, and therefore,
throughout the entire range of the CRLF in the United States. Rationale for each
component assessed is provided in Table 1, which summarizes the "effect
determinations" (findings of this risk assessment) of malathion use to the federally listed
CRLF, and throughout the remainder of this document.

Table 1. Summary of effects determinations and the basis for those determinations for the California
Red-legged Frog (CRLF) from malathion and its degradate/impurity maloxon.	

Assessment
Endpoint

Exposure
(Duration,
Habitat)

Effects
Determination1

Basis for Determination

Direct effects to
CRLF

Acute,
aquatic

LAA

-	Acute LOC2 is exceeded for most uses based
on estimated concentrations of malathion in
water and on the most sensitive surrogate
vertebrate data.

-	At the highest estimated concentration of
malathion in water, the likelihood of individual
mortality is well in excess of 1 in 2.

-	Maximum observed concentrations of
malathion in surface waters are sufficient to
exceed the LOC.



Chronic,
aquatic

LAA

- Chronic LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and on the most sensitive surrogate vertebrate
data extrapolated to a chronic endpoint through
the application of an acute to chronic ratio
(ACR).



Acute,
terrestrial

LAA

-	Using the avian surrogate approach the acute
listed species LOC is exceeded for 53 of 68 use
scenarios.

-	Refined estimates of exposure based on CRLF-
specific diet considerations result in listed
species LOC exceedances for dose-based or
dietary-based exposures for 53 uses and reduces
uses exceeding the non-listed LOC to 8.



Chronic,
terrestrial

LAA

-	Chronic LOC is exceeded for all uses, except
the papaya and residential ornamental and lawn
uses, based on the most sensitive surrogate bird
data.

-	Refined estimates of exposure based on CRLF-
specific diet considerations result in LOC
exceedances for dietary-based exposures except
for papaya and residential ornamental and lawns.

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Assessment
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Indirect effects to
tadpole CRLF via
reduction of
primary
production based
food
(i.e., algae)

Aquatic

NLAA

-	Only the listed species LOC is exceeded for
some uses of malathion.

-	However, the listed species LOC is only
applicable for indirect effects to listed species
with an obligate relationship to a specific plant,
which is not applicable to the CRLF which is a
generalist herbivore.

Indirect effects to
juvenile and adult

CRLF via
reduction of prey
(i.e.,
invertebrates)

Acute,
aquatic

LAA

-	Acute LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and on the most sensitive surrogate invertebrate
data.

-	Estimated concentrations of malathion in water
resulting from all uses result in a likelihood of
individual mortality of 50% to 100% for the
most sensitive species tested.

-	Considering species sensitivity distributions for
aquatic vertebrates and estimated exposure
concentrations for malathion, all uses may affect
substantial numbers of invertebrate species at
50% or greater mortality.



Chronic,
aquatic

LAA

- Chronic LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and the most sensitive surrogate invertebrate
data.



Acute,
terrestrial

LAA

Malathion is an insecticide with a highly varied
suite of agricultural and non-agricultural uses.
Field effects data show that label relevant
application rates can reduce invertebrate
populations at sites of treatment.

Indirect effects to
adult CRLF via
reduction of prey
(i.e., fish, frogs,
and mice)

Acute,
aquatic

LAA

-	Acute LOC is exceeded for several uses based
on estimated concentrations of malathion in
water and the most sensitive surrogate vertebrate
data.

-	At the highest estimated concentration of
malathion in water (resulting from use on
lettuce), the level of effects on exposed
populations exceeds 50%.

-	Maximum observed concentrations of
malathion in surface waters are sufficient to
exceed the LOC.

-	Considering species sensitivity distributions for
aquatic vertebrates and estimated exposure
concentrations for malathion, several uses
(gooseberry, rice/wild rice, watercress, forestry,
and mosquito control) may affect substantial
numbers of fish species at 50% or greater
mortality.

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Assessment
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Chronic,
aquatic

LAA

- Chronic LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and on the most sensitive surrogate vertebrate
data.



Acute,
terrestrial

LAA

-	Acute LOC is exceeded for all uses based on
the most sensitive surrogate amphibian data.

-	Refined estimates of exposure based on
amphibian-specific diet considerations result in
LOC exceedances for dietary-based and dose-
based exposures.

-	For foliar uses, effects determination based on
acute effects to mice is NLAA.



Chronic,
terrestrial

LAA

-	Chronic LOC is exceeded for all foliar uses
based on the most sensitive surrogate
mammalian and amphibian data.

-	Refined estimates of exposure based on
amphibian-specific diet considerations result in
LOC exceedances for dietary-based exposures.

Indirect effects to
CRLF via
reduction of
habitat and/or
primary
productivity (i.e.,
plants)

Aquatic

NE

-	Only the listed species LOC is exceeded for
some uses of malathion.

-	However, the listed species LOC is only
applicable for indirect effects to listed species
with an obligate relationship to a specific plant,
which is not applicable to the CRLF (a generalist
herbivore).



Terrestrial

NE

-There are no data to support any finding that
field relevant effects on terrestrial plants occur
with any field relevant application of malathion.

1LAA = likely to adversely affect; NLAA = not likely to adversely affect; NE = no effect
2LOC (level of concern) is the risk level below which there are no agency concerns.

Aquatic phase CRLF effects. Direct effect levels of concern (LOCs) were exceeded for
CRLF aquatic life stages. Both acute and chronic LOCs were exceeded for aquatic prey
and are of sufficient magnitude to have a significant detrimental impact of prey base of
the CRLF. No observed effect concentration (NOEC) based LOCs were exceeded only
for non-vascular aquatic plants and only for some uses. Reductions of aquatic non-
vascular plant biomass or populations are expected to be temporary and are not
anticipated to measurably affect CRLF present in affected water bodies. Similarly,
malathion and maloxon are not anticipated to significantly impact riparian plant
communities. Vegetation provides habitat (aquatic vegetation) and protects water quality
(riparian vegetation) for the aquatic phase of the CRLF.

Terrestrial phase CRLF effects. Direct terrestrial effects were assessed using EFED's T-
Herps model which incorporates amphibian/reptile specific allometric equations to more
accurately assess affects to CRLF. Acute dose-based RQs exceeded LOCs for small (1.4
g), medium (37 g), and large (238 g) CRLF. Acute and chronic dietary-based RQs
exceeded LOCs for small frogs, which constitutes both direct (on the CRLF itself) and

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indirect (on frogs that may be CRLF prey) effects. Other indirect terrestrial effects were
assessed using EFED's T-Rex model. Dose-based acute and chronic RQs exceeded LOCs
for small mammals. Dietary-based acute and chronic RQs and dose-based acute RQs
exceeded LOCs for small birds. Small mammals, birds, and herptiles are prey items of
the CRLF. Again, malathion and maloxon are not anticipated to significantly impact
riparian plant communities, which also provide habitat and food sources for terrestrial
phase CRLF.

Table 2 summarizes the impacts of malathion to CRLF critical habitat. Designation of
critical habitat is based on habitat areas that provide essential life cycle needs of the
species or areas that contain primary constituent elements (PCEs) (as defined in 50 CFR
414.12(b)). PCEs include, but are not limited to, space for individual and population
growth and for normal behavior; food, water, air, light, minerals, or other nutritional or
physiological requirements; cover or shelter; sites for breeding, reproduction, rearing (or
development) of offspring; and habitats that are protected from disturbance or are
representative of the historic geographical and ecological distributions of a species.

Table 2. Effects determination summary for the critical habitat impact analysis.

Assessment Endpoint

Effects
Determination

Basis

Aquatic Phase PCEs (Aquatic Breeding Habitat and Aquatic Non-Breeding Habitat)

Alteration of channel/pond morphology or
geometry and/or increase in sediment
deposition within the stream channel or pond:
aquatic habitat (including riparian vegetation)
provides for shelter, foraging, predator
avoidance, and aquatic dispersal for juvenile
and adult CRLF.

No effect

Risk of malathion to plants assumed to be
negligible with no expected effects on
terrestrial vegetation and extremely limited
effects on aquatic vegetation that would be
pertinent only to obligate animals.

Alteration in water chemistry/quality
including temperature, turbidity, and oxygen
content necessary for normal growth and
viability of juvenile and adult CRLF and their
food source.1

No effect

Risk of malathion to plants assumed to be
negligible based on presumed low
phytotoxicity and mode of action.

Alteration of other chemical characteristics
necessary for normal growth and viability of
CRLF and their food source.

Habitat
modification

RQs exceeded for acute and chronic effects
for CRLF and prey items (invertebrates,
fish, and aquatic phase amphibians).

Reduction and/or modification of aquatic-
based food sources (e.g., algae) for pre-
metamorphs.

No effect

Aquatic plant effects are only at a level
critical for obligate animals, no habitat
modification relavent to the generalist
CRLF.

Terrestrial Phase PCEs (Upland Habitat and Dispersal Habitat)

Elimination and/or disturbance of upland
habitat; ability of habitat to support food
sources of CRLF: Upland areas within 200 ft
of the edge of the riparian vegetation or drip
line surrounding aquatic and riparian habitat
that are comprised of grasslands, woodlands,
and/or wetland/riparian plant species that
provide the CRLF shelter, forage, and
predator avoidance.

No effect

No effects expected for terrestrial plants.

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Assessment Endpoint

Effects
Determination

Basis

Elimination and/or disturbance of dispersal
habitat: Upland or riparian dispersal habitat
within designated units and between occupied
locations within 0.7 mi of each other that
allow for movement between sites including
both natural and altered sites which do not
contain barriers to dispersal.

No effect

No effects expected for terrestrial plants.

Reduction and/or modification of food
sources for terrestrial phase juveniles and
adults.

Habitat
modification

Malathion poses acute and chronic risk to
prey items of the CRLF (terrestrial
invertebrates, mice, and terrestrial-phase
frogs).

Alteration of chemical characteristics
necessary for normal growth and viability of
juvenile and adult CRLF and their food
sources.

Habitat
modification

Malathion poses acute and chronic risk to
prey items of the CRLF (terrestrial
invertebrates, mice, and terrestrial-phase
frogs).

1 Physico-chemical water quality parameters such as salinity, pH, and hardness are not evaluated because
these processes are not biologically mediated and, therefore, are not relevant to the endpoints included in
this assessment.

When evaluating the significance of this risk assessment's direct/indirect and habitat
modification effects determinations, it is important to note that pesticide exposures and
predicted risks to the CRLF and its resources (i.e., food and habitat) are not expected to
be uniform across the action area or uniform over time. Risks to the CRLF and its
resources are expected to decrease with increasing distance away from the treated field or
site of application because both spray drift through air and dilution with downstream
transport in surface water will cause the pesticide exposure to attenuate with distance.

For sites distant from the site of malathion application, the adverse effects may be
intermittent because malathion is not expected to persist in most environments and the
conditions that cause it to exceed LOCs (e.g., right wind direction, heavy rain
immediately after application, etc.) may occur infrequently. Theses sites may experience
long periods of recovery between exposures of sufficient magnitude to cause any adverse
effects.

For sites closer to the site of malathion application, adverse conditions would be expected
to be more severe, causing mortality to both the CRLF and to the prey items on which the
CRLF depends, and more frequent, providing little time to recover before adverse
conditions re-occur. Because malathion has many uses and most of those uses would
cause adverse effects, it is expected that malathion would cause a larger proportion of
sites to experience severe adverse effects at greater frequency than pesticides that have
fewer uses and less severe effects. Additionally, because malathion does have so many
uses, it is possible that some sites are impacted by multiple uses.

Evaluation of the implication of this non-uniform distribution of risk to the CRLF would
require information and assessment techniques that are not currently available. Examples
of such information and methodology required for this type of analysis would include the
following:

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•	Enhanced information on the density and distribution of CRLF life stages within
specific recovery units and/or designated critical habitat within the action area.
This information would allow for extrapolation of the present risk assessment's
predictions of individual effects to the proportion of the population within the
geographical areas where those effects are predicted to occur. Additionally, such
population-specific information would allow for a more comprehensive
evaluation of the significance of potential resource impairment to individual
CRLF.

•	Quantitative information on prey base requirements for individual aquatic- and
terrestrial-phase CRLF. While existing information indicates the types of food
sources utilized by the frog, it does not establish minimal requirements to sustain
healthy individuals at varying life stages. Such information could be used to
establish biologically relevant thresholds of effects on the prey base and identify
geographical limits to those effect thresholds. This information could be used
together with the density data (discussed above) to characterize the likelihood of
adverse effects to individual CRLF.

•	Information on population responses of prey base organisms to malathion.
Currently, methodologies are limited to predicting exposures and likely levels of
direct mortality, growth, or reproductive impairment of prey base organisms
immediately following exposure to malathion. Potentially, more ecologically
relevant effects to the prey base (e.g., the degree to which repeated exposure
events and inherent demographic characteristics of the prey population limit the
extent to which prey resources may recover) can not currently be predicted. An
enhanced understanding of long-term prey responses to pesticide exposure would
allow for an estimate of the magnitude and duration of resource impairment to be
made. Combining such an estimate with the information described above might
provide a more comprehensive prediction of effects to individual frogs and
potential modification to critical habitat.

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2. Problem Formulation

Problem formulation provides a strategic framework for the risk assessment. By
identifying the important components of the problem, it focuses the assessment on the
most relevant life history stages, habitat components, chemical properties, exposure
routes, and endpoints. This assessment was completed in accordance with the August 5,
2004 Joint Counterpart Endangered Species Act (ESA) Section 7 Consultation
Regulations specified in 50 CFR Part 402 (USFWS/NMFS 2004; FR 69 47732-47762).
The structure of this risk assessment is based on guidance contained in U.S. EPA's
Guidance for Ecological Risk Assessment (U.S. EPA 1998), the Services' Endangered
Species Consultation Handbook (USFWS/NMFS 1998), and procedures outlined in the
Overview Document (U.S. EPA 2004).

2.1 Purpose

The purpose of this endangered species assessment is to evaluate potential direct and
indirect effects on individuals of the federally threatened CRLF arising from the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA) regulatory actions1 regarding use of
malathion. In addition, this assessment evaluates whether malathion use is expected to
result in modification of the CRLF's critical habitat. This ecological risk assessment has
been prepared as part of the Center for Biological Diversity (CBD) us. EPA et al. (Case
No. 02-1580-JSW(JL)) settlement entered in the Federal District Court for the Northern
District of California on October 20, 2006.

In this risk assessment, direct and indirect effects to the CRLF and potential modification
to its critical habitat are evaluated in accordance with the methods described in the
Agency's Overview Document (U.S. EPA 2004). Screening level methods include use of
standard models such as PRZM-EXAMS, TREX, TerrPlant, AgDrift, and AgDisp, all of
which are described at length in the Overview Document. Additional refinements include
a modification of TREX (THERPS) to evaluate effects on terrestrial-phase frogs and an
analysis of the usage data. Use of such information is consistent with the guidance
provided in the Overview Document (U.S. EPA 2004), which specifies that "the
assessment process may, on a case-by-case basis, incorporate additional methods,
models, and lines of evidence that EPA finds technically appropriate for risk management
objectives" (Section V, page 31 of U.S. EPA 2004).

In accordance with the Overview Document, provisions of the ESA, and the Services'
Endangered Species Consultation Handbook, the assessment of effects associated with
registrations of malathion is based on an action area. The action area is the area directly
or indirectly affected by the federal action, as indicated by the exceedance of OPP's

1 Federal actions arising from FIFRA, or other laws, etc. must comply with the National Environmental
Policy Act (NEPA). NEPA's basic policy is to assure that all federal agencies consider the environment
prior to approving federal actions. Specifically, NEPA requires federal agencies to evaluate the potential
environmental effects of their actions prior to approving them. Moreover, NEPA requires federal agencies
to consider measures to minimize adverse effects of their actions, and to solicit and consider public input as
part of the environmental review process.

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Levels of Concern (LOCs). It is acknowledged that the action area for a national-level
FIFRA regulatory decision associated with a use of malathion may potentially involve
numerous areas throughout the United States and its Territories. However, for the
purposes of this assessment, attention will be focused on the section of the action area
that intersects with 1) locations where CLRF is known to occur2, 2) currently occupied
core areas for the CLRF3, and 3) designated critical habitat.

As part of the "effects determination," one of the following three conclusions will be
reached regarding the potential use of malathion in accordance with current labels:

•	"No effect";

•	"May affect, but not likely to adversely affect"; or

•	"May affect and likely to adversely affect".

Critical habitat identifies specific areas that have the physical and biological features,
(known as primary constituent elements or PCEs) essential to the conservation of listed
species. The PCEs for the CRLF are aquatic and upland areas where suitable breeding
and non-breeding aquatic habitat is located, interspersed with upland foraging and
dispersal habitat.

If the results of initial screening-level assessment methods show no direct or indirect
effects (no LOC exceedances) upon individual CRLF or upon the PCEs of the species'
designated critical habitat, a "no effect" determination is made for use of malathion as it
relates to this species and its designated critical habitat. If, however, direct or indirect
effects to individual CRLF are anticipated and/or effects may impact the PCEs of the
CRLF's designated critical habitat, a preliminary "may affect" determination is made for
the FIFRA regulatory action regarding malathion.

If a determination is made that use of malathion within the action area(s) associated with
the CRLF "may affect" this species and/or its designated critical habitat, additional
information is considered to refine the potential for exposure and for effects to the CRLF
and other taxonomic groups upon which these species depend (e.g., aquatic and terrestrial
vertebrates and invertebrates, aquatic plants, riparian vegetation, etc.). Additional
information, including spatial analysis (to determine the co-occurrence of CRLF habitat
with malathion exposure) and further evaluation of the potential impact of malathion on
the PCEs is also used to determine whether modification to designated critical habitat
may occur. Based on the refined information, the Agency uses the best available
information to distinguish those actions that "may affect, but are not likely to adversely
affect" from those actions that "may affect and are likely to adversely affect" the CRLF
and/or the PCEs of its designated critical habitat. This information is presented as part of
the Risk Characterization in Section 5 of this document.

The Agency believes the analysis of direct and indirect effects to listed species provides
the basis for an analysis of potential effects on the designated critical habitat. Because

2	As documented in the California Natural History Database

3	As described in the CRLF recovery plan.

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malathion is expected to directly impact living organisms within the action area (defined
in Section 2.7), critical habitat analysis for malathion is limited in a practical sense to
those PCEs of critical habitat that are biological or that can be reasonably linked to
biologically mediated processes {i.e., the biological resource requirements for the listed
species associated with the critical habitat or important physical aspects of the habitat that
may be reasonably influenced through biological processes). Activities that may modify
critical habitat are those that alter the PCEs and jeopardize the continued existence of the
species. Evaluation of actions related to use of malathion that may alter the PCEs of the
CRLF's critical habitat form the basis of the critical habitat impact analysis. Actions that
may affect the CRLF's designated critical habitat and jeopardize the continued existence
of the species have been identified by the Services (USFWS and NMFS) and are
discussed further in Section 2.6.

2.2 Scope

Malathion is an organophosphate insecticide currently registered in the U.S. for the
following uses:

Exclusively outdoor uses:

Aquatic food and non-food uses: lakes/ponds/reservoirs (with or without human or
wildlife use), intermittently flooded areas/water, polluted water, rice,
swamps/marshes/wetlands/stagnant water, and wild rice;

Forestry (forest/shelterbelt) uses: cottonwood, poplar, red cedar, and slash pine;

Outdoor residential uses: household/domestic dwellings outdoor premises,
refuse/solid waste containers (garbage cans), and urban areas;

Terrestrial feed crop uses: alfalfa, bermudagrass, bluegrass, canarygrass, cereal
grains, clover, corn, grass forage/fodder/hay, lentils, lespedeza, lupine, millet
(foxtail), pastures, peas (including vines), rangeland, sorghum, sudangrass,
timothy, trefoil, and vetch;

Terrestrial food crop uses: agricultural/farm structures/buildings and equipment,
anise, apricot, asparagus, avocado, beets, blackberry, blueberry, boysenberry,
broccoli, broccoli raab, Brussel sprouts, cabbage, caneberries, carrot (including
tops), cantaloupe melon, cauliflower, celery, celtuce, cherry, chervil, chestnut,
Chinese amaranth, Chinese broccoli, Chinese cabbage, collards, corn salad,
cranberry, cucumber, cucurbit vegetables, currant, dandelion, date, dewberry,
dock (sorrel), eggplant, endive (escarole), fennel, fig, filbert (hazelnut), food
processing plant premises (nonfood contact), garden purslane, garland
chrysanthemum, garlic, green onions, gooseberry, guava, head lettuce, honeydew
melon, horseradish, kale, kohlrabi, leaf lettuce, leek, loganberry, macadamia nut
(bushnut), mango, meat processing plant premises (nonfood contact), melons,
mint, musk melon, mustard, mustard cabbage (gai choy/pak-choi), nectarine,
okra, onion, orach (mountain spinach), papaya, parsley, passion fruit (granadilla),
peach, pear, pecan, pepper, pineapple, plum, prune, pumpkin, quince, radish,
raspberry (black or red), roquette (arrugula), rutabaga, salsify, shallot, spinach,

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squash (all or unspecified), strawberry, sweet corn, sweet potato, Swiss chard,
walnut (English/black), water cress, water melon, winter melons
(casaba/crenshaw/honeydew/persian), and winter purslane;

Terrestrial food andfeed crop uses: almond, apple, barley, beans, canola\rape,
cereal grains, citrus, citrus hybrids other than tangelo, compost/compost piles,
corn (unspecified), cotton (unspecified), cowpea/black-eyed pea, dried beans,
field corn, field peas, flax, grape leaves, grapefruit, grapes, hops, kumquat, lemon,
lentils, lime, manure, mint, mustard, oats, orange, parsnip, peanuts (unspecified),
peas (unspecified), peppermint, pineapple, pop corn, rice, rye, safflower
(unspecified), salsify, sorghum, soybeans (unspecified), spearmint, succulent
beans (lima), succulent beans (snap), sugar beet, sweet corn, tangelo, tangerines,
tomato, turnip, wheat, wild rice, and white/irish potato;

Terrestrial non-food crop uses: agricultural fallow/idle land,
automobiles/taxis/limousines/recreational vehicles and tires, Christmas tree
plantations, citrus, clover, commercial/institutional/industrial premises/equipment
(outdoor), cull piles, golf course turf, meat processing plant premises (nonfood
contact), nonagricultural areas (public health use), nonagricultural outdoor
buildings/structures, nonagri cultural rights-of-way/fencerows/hedgerows,
nonagri cultural uncultivated areas/soils, ornamental and/or shade trees,
ornamental herbaceous plants, ornamental non-flowering plants, ornamental
woody shrubs and vines, pine (seed orchard), refuse/solid waste sites (outdoor),
tobacco, urban areas, and wide area/general outdoor treatment (public health use);

Terrestrial non-food and outdoor residential uses: cull piles,
fencerows/hedgerows, nonagricultural rights-of-way/fencerows/hedgerows,
ornamental and/or shade trees, ornamental herbaceous plants, ornamental lawns
and turf, ornamental non-flowering plants, ornamental woody shrubs and vines,
and urban areas;

Exclusively indoor uses:

Greenhouse food crop uses: beans, cucumber, eggplant, endive (escarole), head
and leaf lettuce, mushrooms, onion, pepper, and tomato;

Indoor food uses: agricultural/farm structures/buildings and equipment, almond,
barley, barns/barnyards/auction barns, beef/range/feeder cattle (meat), cereal
grains, citrus pulp (processed), commercial transportation facilities-feed/food-
empty, corn (unspecified), dairy cattle (non-lactating), feed/food storage areas-
empty, field corn, food processing plant premises (nonfood contact), goats (meat),
goats (wool/angora animal), empty grain/cereal/flour elevators and storage areas,
hog/pig/swine (meat), livestock, meat processing plant premises (nonfood
contact), mushrooms, oats, peanuts, pop corn, poultry (egg/meat), rice, rye, seed
houses/stores/storage areas/warehouses, seeds, sheep (meat), sorghum, sunflower,
and wheat;

Indoor non-food uses: non-feed/non-food commercial transportation facilities,
sheep, and wide area/general indoor treatment;

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Indoor residential uses: household/domestic dwellings indoor premises and
refuse/solid waste sites (indoor);

Indoor and outdoor uses:

Terrestrial and greenhouse food crop uses: beans, cucumber, dried beans,
eggplant, endive (escarole), green onions, head lettuce, leaf lettuce, onion, pepper,
squash (all or unspecified), succulent beans (lima), succulent beans (snap), sweet
corn, and tomato;

Terrestrial and greenhouse non-food crop uses: ornamental and/or shade trees,
ornamental herbaceous plants, and ornamental woody shrubs and vines

The scope of this assessment includes all of the "exclusively outdoor" and "indoor and
outdoor" uses for the active ingredient malathion (and its impurity and degradate,
maloxon), but does not address other inert ingredients which may be present in an end-
use product or tank mixture. Exclusively "indoor" uses are assumed to have "no effect"
on the CRLF if used in accordance with the label and are not considered further in this
risk assessment.

The end result of the EPA pesticide registration process (the FIFRA regulatory action) is
an approved product label. The label is a legal document that stipulates how and where a
given pesticide may be used. Product labels (also known as end-use labels) describe the
formulation type (e.g., liquid or granular), acceptable methods of application, approved
use sites, and any restrictions on how applications may be conducted. Thus, the use or
potential use of malathion in accordance with the approved product labels for California
is "the action" being assessed.

Although current registrations for malathion allow for use nationwide, this ecological risk
assessment is for currently registered uses of malathion in portions of the action area that
are reasonably assumed to be biologically relevant to the CRLF and its designated critical
habitat.4

The Agency does not routinely include, in its risk assessments, an evaluation of mixtures
of active ingredients, either those mixtures of multiple active ingredients in product
formulations or those in the applicator's tank. In the case of the product formulations of
active ingredients (that is, a registered product containing more than one active
ingredient), each active ingredient is subject to an individual risk assessment for
regulatory decision regarding the active ingredient on a particular use site. If effects data
are available for a formulated product containing more than one active ingredient, they
may be used qualitatively or quantitatively in accordance with the Agency's Overview
Document and the Services' Evaluation Memorandum (U.S., EPA 2004; USFWS/NMFS
2004).

4 Technical labels also exist, which may include crops not listed on end use labels. Technical products are
used to make formulated end use products. Because these technicals cannot be applied directly, use sites on
these labels are not considered at part of the Federal action.

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Malathion has registered products that contain multiple active ingredients. Analysis of
the available acute oral mammalian LD50 data for multiple active ingredient products
relative to the single active ingredient is provided in Appendix A. The results of this
analysis show that an assessment based on the toxicity of the single active ingredient of
malathion is appropriate.

2.3	Previous Assessments

Both malathion and the CRLF have been subjects of previous ecological risk
assessments. The Agency has completed a RED (U.S. EPA 2006)5 for malathion. The
malathion ecological risk assessment for the RED identified an exceedence of the
endangered species risk level of concern (LOC) for fish, aquatic invertebrates, birds, and
mammals. Furthermore, the RED document concluded that concerns for risks to
endangered species of terrestrial invertebrates and plants could not be precluded based on
available data and baseline risk assessment methods.

Assessment endpoints in this document are lower than those used in the malathion RED.
Although the RED was published in 2006, following completion of the organophosphate
cumulative assessment, this ecological risk assessment was compiled in 1999, prior to the
regular incorporation of open literature (ECOTOX) data into EFED risk assessments.
Review of the open literature data resulted in a number of lower endpoints. Risk
conclusions are similar, in that a listed species LOCs are exceeded, but the risk quotients
(RQs) presented in this document are higher than corresponding RQs in the RED.

The Agency is currently developing a number of risk assessments for the CRLF, each
addressing a different pesticide active ingredient. A total of 66 pesticides6 will be
assessed. Malathion is among the second group of 10 pesticides to be completed. For
information regarding other pesticides, please see the relevant document.

2.4	Malathion Characteristics, Fate, and Transport

Malathion has specific properties and uses which help delineate when and where the
active ingredient and/or any impurities/degradates may co-occur temporally and spatially
with the CRLF with sufficient intensity (sufficient concentration) to affect the CRLF. For
reasons explained in Section 2.4.6, only malathion and one of its degradates (also an
impurity), maloxon, are included in this risk assessment. Sections 2.41 through 2.4.7

5	Available via the internet at http://www.epa.gov/oppsrrdl/reregistration/REDs/malathion_red.pdf

6	Other chemicals being assessed include 1,3-dichlorpropene, 2,4-D, acephate, alachlor, aldicarb, atrazine,
azinphos-methyl, bensulide, bromacil, captan, carbaryl, chloropicrin, chlorothalonil, chlorpyrifos,
chlorthal-dimethyl (DCPA), DEF (tribufos), diazinon, dicofol, diflubenzuron, dimethoate, disulfoton,
diuron, endosulfan, EPTC, esfenvalerate, fenamiphos, glyphosate, hexazinone, imazypyr, iprodione,
linuron, mancozeb, maneb, metam sodium, methamidophos, methidathion, methomyl, methoprene, methyl
parathion, metolachlor, molinate, myclobutanil, naled, norflurazon, oryzalin, oxamyl, oxydemeton-methyl,
oxyfluoren, paraquat dichloride, pendimethalin, permethrin, phorate, phosmet, prometryn, propanil,
propargite, propyzamide (pronamide), rotenone, simazine, strychnine, thiobencarb, triclopyr, trifluralin,
vinclozolin, and ziram.

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summarize a wealth of fate data discussed in the RED (USEPA 2006). For a more
detailed discussion of the available fate data, please see that document.

2.4.1 Chemical Profile

The basic physical and chemical properties and structure of malathion are presented in
Table 3. Maloxon differs structurally from malathion by the substitution of a doubly-
bonded oxygen to phosphorus in place of the doubly bonded sulfur (identified by red box
in chemical structurediagram) and has a slightly lower molecular weight of 314.29 g/mol.
Throughout this assessment many of the properties of malathion are assumed to apply to
maloxon due to the similarities in chemical structure. This assumption is made necessary
due to the dearth of information on maloxon relative to the amount of information
available for malathion.

Table 3. Physical/chemical properties of malathion (0,0-dimethyl phosphorodithioate of diethyl
mercaptosuccinate).			

Physical/Chemical Property

V alue/Description

Chemical Structure

Molecular formula

CuftgOsPS,



Molecular weight

330.3 g/mol

ju-

Physical state

Clear amber liquid

Melting point

2.85° C

Boiling point (0.7 mm Hg)

156 - 157° C

Specific gravity (25° C)

1.23

A-

Vapor pressure (30° C)

4 x 10"5 mm Hg

Solubility (25°C)

145 mg/1 water

2.4.2 Mechanism of A ction

Several reviews of malathion and organophosphate toxicology exist including Matsumura
(1985).

Malathion's mode of action is through acetylcholinesterase (AChE) inhibition which
disrupts nervous system function. AChE is an enzyme which cleaves the neurotransmitter
acetylcholine that resides within nervous system junctions. Inhibiting this enzyme leads
to accumulation of the neurotransmitter thus causing signals in the nervous system to
persist longer than normal. Typical symptoms for exposure to pesticides which act in this
manner are defecation, urination, lacrimation, muscular twitching and weakness, and
halted respiration.

Malathion, along with other phosphorodithioate insecticides (those containing two sulfur
atoms bonded to phosphorus) must be oxidized before they have inhibitory potency and
toxicity. Oxidation occurs via cytochrome p450 and results in the conversion of the P=S
group in malathion to P=0 forming its oxon, maloxon (Murphy et al 1968). This
alteration of the phosphate group enables the molecule to covalently bind AChE resulting
in long lasting inhibition of the enzyme.

Maloxon binds to AChE by mimicking the structure of enzyme's natural substrate,
acetylcholine. The similarity between the size, shape, and properties of maloxon and the

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neurotransmitter allow it to "fit" in the acetylcholine binding site on the enzyme. Altering
the structure of maloxon or malathion reduces the ability of the oxon to bind AChE
resulting in detoxification of the molecule.

Detoxification reactions may be a result of enzyme or chemical action on the molecule
and occurs very rapidly in mammals giving pure malathion a very low acute toxicity
[LD50 in rats is 12,500 mg/kg (Fukuto 1983)]. Common detoxification reactions for
malathion (and maloxon) are ester hydrolysis, demethylation, and phosphorothiolate ester
hydrolysis. When one or more of these detoxification steps are blocked by another
chemical the toxicity of malathion is increased and the added chemical is considered to
synergize malathion toxicity. Chemicals which increase the rate of malathion's
conversion to maloxon may also be synergists.

Important detoxification steps occur through nonspecific esterase enzymes which are
capable of cleaving malathion to less toxic degradates. Biological and environmental
degradates of malathion with greatly lowered toxicity include malathion a, P, and diacids,
and O-desmethyl malathion (Matsumura 1985).

Because organophosphate insecticides are inhibitors of esterases (most specifically
AChE) they possess the ability to block detoxification enzymes. Several organophosphate
impurities present in technical malathion are known to synergize malathion toxicity
probably through blocking malathion detoxification. The toxicity of several malathion
impurities alone is also very high (e.g., the LD50 of 0,0,S-trimethyl phosphorothioate in
rats is 15 mg/kg, or 833 times more toxic than pure malathion) and cause delayed toxicity
suggesting a mode of action other than AChE inhibition. Impurities can be produced
through improper storage of malathion as evidenced by a 35% increase in the acute
toxicity of technical malathion stored at 40°C for 6 months (Fukuto 1983).

2.4.3 Malathion Products with Additional Active Ingredients

The Agency does not routinely include, in its risk assessments, an evaluation of mixtures
of active ingredients, either those mixtures of multiple active ingredients in product
formulations or those in the applicator's tank. In the case of the product formulations of
active ingredients (that is, a registered product containing more than one active
ingredient), each active ingredient is subject to an individual risk assessment for
regulatory decision regarding the active ingredient on a particular use site. If effects data
are available for a formulated product containing more than one active ingredient, they
may be used qualitatively or quantitatively in accordance with the Agency's Overview
Document and the Services' Evaluation Memorandum (U.S., EPA 2004; USFWS/NMFS
2004).

Malathion has registered products that contain multiple active ingredients. Analysis of the
available acute oral mammalian LD50 data (and available open literature for malathion)
for multiple active ingredient products relative to the single active ingredient is provided
in Appendix A. The results of this analysis show that an assessment based on the toxicity
of the single active ingredient of malathion is appropriate.

16


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2.4.4 Environmental Fate Assessment

CRLF may be exposed to malathion and its degradates through contamination of food,
water, and air (by suspended particles) which can result from off-target drift, runoff, and
direct application. Increased toxicity may be brought about through oxidation (to
maloxon). Limited data are available on toxic degradates and impurities, but the fate data
provided to EFED for malathion was found to be acceptable for performing risk
assessment (USEPA 2006) and shows that malathion, typically, will have little
persistence in the environment.

Based on registrant submitted data and open literature reports, EFED concludes the
primary routes of dissipation of malathion in surface soils appear to be microbially-
mediated soil metabolism (half-lives measured as <1 to 2.5 days) and hydrolysis (pH 7
and 9 half-lives of 6.21 days and 12 hours, respectively). Malathion monoester, ethyl
hydrogen fumarate, diethyl thiosuccinate, malathion mono- and dicarboxylic acids,
demethyl mono- and di-carboxylic acids, and C02 are known degradates.

2.4.4.1	Degradation

Hydrolysis: Several open literature studies (Mulla et al 1981, Howard 1991) are
consistent with data presented by the registrant showing that malathion is unstable under
alkaline conditions and increasingly stable under acidic conditions. Malathion is stable to
hydrolysis at pH 5 (Ti/2 = 107 days), to aqueous photolysis (Ti/2 = 94 and 143 days,
corrected for dark control) and to soil photolysis (Ti/2 =173 days) and does not volatilize
appreciably (<5.1% of applied volatilized after 16 days). Open literature studies suggest
persistence on soil is longer under dry, sandy, low nitrogen, low carbon, and acidic
conditions (Walker and Stojanovic 1973).

The phosphorothiolate ester bond of maloxon may be more susceptible to cleavage via
hydrolysis than the analogous phosophorodithioate ester in malathion. Greater
susceptibility would lead to reduced persistence for maloxon relative to malathion.

2.4.4.2	Metabolism

Aerobic soil Metabolism : Aerobic soil metabolism is an important route of malathion
degradation. Malathion persistence under aerobic soil conditions has been examined in
several open literature studies which are reviewed in Table 4. Reported half-life values
(from field and laboratory studies) vary from hours to 11 days. Persistence is decreased
with microbial activity, moisture, and high pH.

Table 4. Open literature studies reporting aerobic soil metabolism degradation rates.

Sou rce

Degradation Rate Value

Comments

Miles and Takashima 1991

t/2 = 8.2 h (laboratory)
t/2 = 2 h (field)

Malathion was mixed with Lihue
soil and incubated at 22°C in lab
experiment. Sterilization decreased
rate by 2-fold.

17


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Source

l)cur;i(l;ilion Ksilc Value

( omnioiils

Walker and Stojanovic 1974

47-95% at 7 days

Malathion was incubated with
various Arthrobacter species.
Degradation in the presence of the
5 most efficient species was
reported.

Walker and Stojanovic 1973

t/2 = ~ 2 days under non-sterile
unfavorable degradation
conditions.

In 3 Mississippi soils examined at
25-26°C, soil microflora were
important in degradation. Slowest
degradation occurred in soils with
low nitrogen, moisture, and carbon
content and increased acidity.

Ca.1F,PA 1994

DT50 = 4.2-6.9 days on sand

Measured at 5 sites under the
conditions of the medfly
eradication program. Each site
consisted of 10 aluminum trays
containing 500g of playground
sand. Between applications trays
were covered.

Ca.1F.PA 1993

DT50 < 12 h on sand

Application was under controlled
conditions, but temperature was not
noted.

Ca.1F.PA 1993

soil:

38% remaining at 12 hours
15% remaining at 20 days

66% sand, 24% silt, 10% clay,
0.78% water, pH 6.3. Malathion
was applied under controlled
conditions. Degradation was
biphasic.

Kearney el al 1969

75-100% degradation in 1 week

Field persistence

Lichtenstein and Schultz 1964

85% dissipation in 3 days

Conducted under field conditions

Howard 1991

Reported average literature

t ,/2 = 6 d

In this review, persistence is stated
to vary with moisture content and
pH.

USD A

t/2 = 3 days used for modeling

This value was chosen for
modeling malathion in the Boll
Weevil Eradication Program based
on a personal communication with
a previous malathion registrant.

In the registrant submitted study [2,3-14C]malathion degraded with a calculated half-life
of approximately 0.2 days in two aerobic metabolism experiments using loam soil (pH
6.1) incubated in the dark at 22 ± 2°C and 75% of field capacity. An ancillary experiment
was conducted to determine the rate of degradation of malathion in sterile soil. At 4 days
post-treatment, malathion comprised close to 100% of the applied radioactivity (97.84%
of the extractable radioactivity). The difference between half lives of the sterile and non-
sterile treatments indicates that microorganisms are important in the rapid degradation of
malathion in soil under acidic aerobic conditions (MRID 41721701, 43166301).

Numerous degradates were identified in the soil extracts and are identified as follows as a
percent of applied radioactivity: dicarboxylic acid of malathion (18.7 - 36.7%), the beta

18


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monocarboxylic acid of malathion (2.8 - 7.3%), the alpha monocarboxylic acid of
malathion (1.9 - 2.5%), and maloxon (0.6 - 1.8%).

Anaerobic Aquatic Metabolism: An open literature study (Bourquin 1977) and the
registrant's study suggest that malathion persistence in anaerobic environments is short,
however, due to the high pH in the registrant's study a quantitative assessment of the
degradation and degradation products cannot be performed.

In the registrant submitted anaerobic aquatic metabolism study [2,3-14C]- and technical
grade-malathion added to a sandy loam soil degraded with a registrant-calculated half-life
of approximately 2.5 days in sediment (pH 7.8) and water (pH 8.7). This study provides
useful information, but hydrolysis was probably the main route of degradation in the
study since the pH of the system was in the basic range which favors hydrolysis.

Although most of the residues remained in the water phase (less than 20% of the applied
radioactivity was associated with the soil at any sampling interval), the degradation
products were similar in both sediment and water phases. The degradation products at
maximum concentrations in the water phase were the monocarboxylic acid of malathion
(MCA, 28%) at Day 4), demethyl monocarboxylic acid (21% at Day 7), dicarboxylic acid
(21 % at Day 14) and the demethyl dicarboxylic acid metabolite (39% at Day 45). The
degradation products at maximum concentrations in the sediment were the
monocarboxylic acid of malathion (4.5% at 6 hours), demethyl monocarboxilic acid
(8.1%) at Day 45), and dicarboxylic acid (5.2%> at Day 4). The EFED calculated half-life
for malathion monocarboxylic acid was 11 days.

Aerobic Aquatic Metabolism: A USGS monitoring study (1997) shows detections of
malathion in large rural and urban streams. Many open literature studies have been
conducted on the fate and persistence of malathion in the aquatic environment. Reported
degradation rates vary and are likely to be significantly increased by biodegradation and
pH. Eichelberger and Lichtenberg (1971) found 75%> and 90%> degradation in river water
in one and two weeks, respectively. Guerrant et al (1970) found malathion half lives in
pond, lake, river and other natural waters varied from 0.5 to 10 days and was dependent
on pH. Other studies are summarized in Mulla et al (1981) and Howard (1991).

Registrant submitted studies were conducted under alkaline conditions which favor
hydrolysis. Thus, degradation rate and products may not be representative of acidic
aquatic conditions. In the registrant submitted aerobic aquatic metabolism study, a
mixture of [2,3-14C]- and technical grade-malathion added to a sandy loam soil rapidly
degraded in the aerobic aquatic environment with half-lives of approximately 1.09 days
in the water phase (pH 7.8) and 2.55 days in sediment (pH 8.5). As mentioned previously,
hydrolysis was probably the main route of degradation in the study since the pH of the
system was in the basic range and hydrolysis occurs most rapidly at pH 9. Major
degradates in water and soil were similar: mono- and dicarboxylic acids of malathion,
demethyl monoacid and demethyl diacid, while in sediment no demethyl diacid was
detected. The EFED calculated half-life for malathion monocarboxylic acid was 3 days.

19


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2.4.4.3 Dissipation

Data from the field dissipation studies indicate that malathion dissipates rapidly when
applied in the field.

Terrestrial field dissipation: Open literature studies provide varying rates of terrestrial
dissipation. Mulla etal (1981) summarizes degradation results from several field studies
including: no residues after 6 months (Roberts etal 1962), and 85% degradation in 3 days
and 97% in 8 days (Lichtenstein and Schulz 1964). The fastest route of terrestrial field
dissipation is generally accepted to be microbial degradation.

In the registrant submitted field dissipation study using a rate of 1.16 lb ai/A, malathion
or maloxon residues were detected at <10 |ig/kg in the 0-6" layer in cotton/bare ground
sites in GA. Due to the sampling depth it is not possible to determine how much
malathion remained at the soil surface relative to that which moved through the first six
inches. Residues detected in the plots in the 6-12" layer after the 2nd, 3rd, 4th, and 5th
treatments averaged 35, 37, 5.6, and 9.4 ng/kg, respectively. Malathion was detected in
the 12-18 inch soil depth at 16 |ig/kg in one replicate soil sample; however, the detection
was attributed to contamination. The detection of malathion below six inches along with
the low Kd values reported for malathion make it feasible that leaching below 12 inches
may have occurred in the field dissipation studies.

The terrestrial field dissipation half-life could not be determined due to the rapid
dissipation of malathion, although it is probably <1 day (MRID 41748901, 43042401,
43166301).

In a field dissipation study located in California, malathion was applied at a maximum
rate of 1.16 lb ai/A once a week for 6 weeks. The resulting dissipation half-life was <0.2
days. In certain instances, malathion was detected below the 12 inch soil depth (MRID
41727701, 43042402, 43166301).

Aquatic field dissipation: Open literature references detailing persistence in aquatic
environments are briefly mentioned under the aquatic metabolism section.

In the first registrant aquatic field dissipation study located in Missouri, malathion was
applied at a maximum rate of 0.58 lb ai/A in three weekly applications to a flooded rice
paddy (soil pH 6.1, water pH not stated). Malathion residues detected in water samples
collected after the first and second application had dissipated to below the detection limit
(10 |ig/L) in samples taken prior to the second and third applications. In water samples
collected one day after the last application, malathion concentrations averaged 17 |ig/L
and had decreased to 10 |ig/L by the second sampling day. Maloxon residues were
10 |ig/L at all sampling dates.

The data indicate a very rapid dissipation of malathion in water, probably <1 day;
however, an accurate half-life could not be determined because of the rapid dissipation
(MRID 42058402, 43166301).

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In the second aquatic field dissipation study performed in California (soil pH 7.4, water
pH not stated), malathion was applied at a rate of 0.58 lb ai/A in three weekly
applications to flooded plots. The resulting dissipation half-life could not be determined
in the California plot because it was probable that only 1-2% of the intended amount of
malathion was applied (MRID 42058401, 43166301).

2.4.4.4 Accumulation in Fish

Aquatic bioconcentration factors ranging from 7.36 (lake trout), 29.3 (coho salmon), 869
(white shrimp), to 959 (brown shrimp) are summarized in Howard (1991).

The registrant submitted study shows [14C]malathion residues did not significantly
accumulate in bluegill sunfish exposed to 0.99 |ig/L [14C]malathion in a flow-through
system for 28 days. Average concentrations of malathion were 3.9 to 18 |ig/kg in the
edible portions of fish, 21 to 130 |ig/kg for whole fish, and 34 to 200 |ig/kg in the non-
edible tissue. [14C]malathion residue equivalents in the edible fish tissue during
depuration ranged from 18 |ig/kg at the start to 4.8 |ig/kg by day 14. Whole fish
concentrations decreased from 110 to 4.5 |ig/kg and non-edible fish concentrations
decreased from 150 to 5.8 |ig/kg after day 14. Approximately 73, 96, and 96% of the
radioactivity depurated by day 28 from the edible, whole, and non-edible portions of fish,
respectively. The non-depurated radioactivity consisted of up to 22 other components
present in concentrations <10% of total applied radioactivity and were not further
identified.

The only residue detected in fish tissue at >10% of total radioactive residues (TRR) was
malathion monocarboxylic acid (MCA) in concentrations of 33.3-35.9% (44.8-61.2
|ig/kg) of TRR. Up to 22 other components were present in levels of 0.1 to 5.7% (0.1 to
7.7 |ig/kg) and included malathion dicarboxylic acid (MDCA), maloxon, desmethyl
malathion, monoethylfumarate and oxalacetic acid. Maloxon was present in
concentrations <2.7 |ig/kg; while parent malathion was present in concentrations of
0.2 ng/kg.

Maximum BCFs, as a function of radioactive residues present, ranged from 4.2 to 18, 23
to 135, and 37 to 204 for edible, whole fish, and non-edible, respectively (MRID
43106401, 43106402, 43340301).

2.4.5 Environmental Transport Summary

Other important routes of dissipation from soil suggested by the data include leaching,
plant uptake, and surface runoff. Malathion and its degradates, in general, are soluble and
do not adsorb strongly to soils.

Acceptable leaching data on parent malathion indicate that it is mobile in all soils tested
(KdS of 0.82 - 2.47). Acceptable terrestrial field dissipation data indicate rapid dissipation
(T1/2 = <2 days). One detection of malathion below 12 inches was found in a terrestrial
field dissipation study, indicating leaching as a likely route of dissipation. Similarly,
column leaching studies demonstrated that malathion and its degradates, malathion

21


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mono- and dicarboxylic acids are very mobile in soil. Data presented to the Agency and
in the "Pesticides and Groundwater Database" (USEPA 1992) demonstrate that malathion
has the potential to leach to ground water. Malathion has been detected in ground water
in three states (California, Mississippi, and Virginia) at levels ranging from 0.03 to
6.17 |ig/L. Based on these data and the low Kd values, it is clear that malathion has the
potential to leach to ground water.

Although little or no maloxon production is observed in registrant submitted aquatic
studies, maloxon has been detected in surface waters and the potential for maloxon runoff
may be heightened relative to malathion because it is expected to have higher solubility.
EFED is not aware of reports of maloxon groundwater contamination. However,
malathion has contaminated groundwater in several states and has the potential to
contaminate surface water through runoff. The increased polarity of maloxon due to the
substitution of oxygen for sulfur increases the expected potential of this chemical to be
mobile in soil.

It is clear that under many circumstances malathion degrades rapidly to compounds of
lower toxicity, usually through microbial metabolism and hydrolysis. However, in urban
areas (e.g., aerial and ground application for mosquito control), it is likely that malathion
will contact dry, microbially inactive, and low organic content surfaces such as concrete,
asphalt, dry soil, roofing material, and glass. It is expected that maloxon production will
be increased on these surfaces as malathion is exposed to air for extended periods until it
is washed away by rain. This is supported by maloxon monitoring data in urban streams
after malathion treatments to urban areas showing similar or higher levels of maloxon
than malathion in some instances (CaEPA, 1981). CaEPA has published two studies
measuring maloxon production on dry soil (CaEPA 1993) and steel sheets (CaEPA
1996). Both of these studies showed higher maloxon production than registrant submitted
studies, but maximal levels of maloxon production were not achieved. On the steel
surface a rainfall event removed most of the malathion after only 2 days. On the dry soil
maloxon production did not decrease by the time the study was terminated at 22 days.

CaEPA has published a study describing maloxon production on low organic content soil
(0.6%) with a moisture content less than 1% (CaEPA 1993) showing higher maloxon
production than registrant submitted studies using soils with higher organic (2-2.7%) and
moisture (75% of water holding capacity, capacity not stated) content. Based on the
CaEPA data, it appears that maloxon production is favored on dry soils and thus may
represent a higher risk scenario for maloxon production and runoff.

Leaching/adsorption/desorption: The short soil persistence of malathion reduces the risk
of leaching to groundwater however it has been detected in the groundwater of at least
three states (USEPA 1992). Demethyl and carboxylic acid degradates are expected to be
highly mobile particularly in alkaline soils.

Based on batch equilibrium (adsorption/desorption) studies, unaged [14C]malathion was
determined to be very mobile in sandy loam, sand, loam, and silt loam soils, with
Freundlich Kads values of 0.83 - 2.47 and Koc values from 151-183. Adsorption was

22


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correlated with organic carbon content. Values for 1/n for Kads were clustered in the range
of 0.904 - 0.978 (MRID 41345201).

Maloxon was not detected in any leachate or soil extracts in concentrations >0.12%
(>6 |ig/L) of applied radioactivity (MRID 43868601, 41345201, 43166301)

Laboratory volatility: Three different malathion formulations [Ready To Use (RTU),
Ultra Low Volume (ULV), and Emulsifiable Concentrate (EC)] added to a silt loam soil
did not undergo any appreciable volatilization, when measured under different soil
moisture regimes or air flow rates. No more than 5.1% of the applied radioactivity
volatilized during the 16 days of the study.

Spray Drift: No registrant-submitted spray drift studies were reviewed. A study
conducted for the Boll Weevil Eradication Program at Pennsylvania State University
(1993) examined malathion drift under conditions of boll weevil control (1 lb/A =112
mg/m2) with an ultra-low volume (ULV) formulation. Deposition up to 21.0, 11.5, 2.9,
and 0.7%) of that applied was observed at 100, 200, 500, and 1000 meters downwind,
respectively. Due to the size of the particles generated, the ULV formulation is expected
to produce the highest levels of drift.

EFED policy is to assume spray drift is equal to 1%> of the applied spray volume from
ground applications and 5%> from aerial and orchard airblast applications at 100 feet
downwind. It is important to note that drift studies on ULV malathion show significantly
higher levels of drift.

2.4.6 Degradates and impurities

Technical malathion contains impurities that account for up to 5%> of the insecticide.
California Department of Food and Agriculture has reported 15 impurities in a
representative ultra low volume malathion formulation (CaEPA 1981). These impurities
include:

Diethyl fumarate (0.90%);

Diethylhydroxysuccinate (0.05%);

0,0-dimethylphosphorothioate (0.05%);

0,0,0-trimethyl phosphorothioate (0.45%);

0,0,S-trimethyl phosphorodithioate (1.20%);

Ethyl nitrite (0.03%);

Diethyl-bis (ethoxycarbonyl) mercaptosuccinate (0.15%);

S-l,2-ethyl-0,S-dimethyl phosphorodithioate [isomalathion] (0.20%);

S-(l-methoxycarbonyl-2-ethoxycarbonyl)ethyl-0,0-dimethyl phosphorodithioate (0.60%);

Bis-(0,0-dimethyl thionophosphoryl) sulfide (0.30%);

Diethyl methylthiosuccinate (1.00%);

S-ethyl-0,0-dimethyl phosphorodithioate (0.10%);

S-l,2-bis (ethoxycarbonyl) ethyl-0,0-dimethyl phosphorothioate [maloxon] (0.10%);

Diethyl ethylthiosuccinate (0.10%); and
Sulfuric acid (0.05%).

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Some malathion (and other organophosphate) impurities can potentiate malathion toxicity
and also are toxic alone, but there is almost no data available on their environmental fate.
The persistence of a phosphorothioate impurity (0,0,S-trimethyl phosphorothioate) was
shown to be 18.7 times longer than malathion in an aerobic soil metabolism study (Miles
and Takashima 1991). Some phosphorothioates and -dithioates have been intensively
studied and induce a delayed toxic effect to mammals at much lower levels than pure
malathion (Ali Fouad and Fukuto 1982, Umetsu etal 1977, Fukuto 1983, Aldridge etal
1979, Toia et al 1980). A phosophorothioate and -dithioate impurity identified by CaEPA
(1981) is of lower toxicity than impurities reported in older formulations (Toia et al
1980). One hydrolysis product, diethyl fumarate, which is also present as an impurity in
technical malathion is approximately 3 times more toxic to fathead minnows than
malathion (Bender 1969). No guideline studies have been conducted and little open
literature data exist to define the fate and persistence of impurities of malathion, however,
most of the highly toxic impurities identified in past studies on malathion (Ali Fouad and
Fukuto 1982, Umetsu et al 1977, Fukuto 1983, Aldridge et al 1979, Toia et al 1980) have
not been identified or are present only at low levels in more recently produced technical
malathion (CaEPA 1981 and confidential information provided by the registrant).

The relative concentration of malathion impurities can vary dramatically depending not
only on manufacturing processes but also storage conditions. Umetsu etal (1977)
concluded "Storage of technical malathion for 3 to 6 months at 40 degrees C resulted in
materials which were noticeably more toxic to mice." Therefore, the composition and
toxicological properties of the technical malathion are not only affected by initial purity,
but also by storage conditions.

One impurity and degradate of malathion is the oxon analog, maloxon, which is also the
active acetyl cholinesterase inhibiting component in vivo. EFED does not have a
complete environmental fate database for maloxon but based on its chemical similarity to
malathion (sulfur is replaced by oxygen), the parent and its degradate are expected to
have similar chemical properties. The aerobic half-life of maloxon has been reported as 3
and 7 days in basic and acidic soils, respectively (Paschal and Neville 1976). This longer
half-life relative to malathion is proposed to be a result of maloxon's biocidal effect on
soil microbes which contribute to malathion's degradation.

Malathion impurities and degradates were evaluated for inclusion in the current risk
assessment. Because the expected effects of most impurities/degradates (based on their
expected concentrations and toxicity) did not exceed the expected effects of malathion,
almost all of the malathion impurities/degradates will not be considered further in this
risk assessment. Only maloxon is included in this risk assessment as both a degradate and
an impurity.

2.4.7 Use Profile

The current labeled uses for malathion represents the FIFRA regulatory action; therefore,
use sites and application rates specified on the label form the basis of this assessment.
The assessment of use information is critical to the development of the action area and
selection of appropriate modeling scenarios and inputs.

24


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The Office of Pesticides Programs' Biological and Economic Analysis Division (BEAD)
provides an analysis of both national- and county-level usage information using state-
level usage data obtained from USDA-NASS7, Doane8, and the California's Department
of Pesticide Regulation Pesticide Use Reporting (CDPR PUR) database9. CDPR PUR is
considered a more comprehensive source of usage data within California than USDA-
NASS or EPA proprietary databases, and thus the usage data reported by county in this
California-specific assessment were generated using CDPR PUR data. From the CDPR
PUR data, BEAD generated summaries of average and total usage by year, county, and
crop for the years 2001 - 2005 (the most recent data available.)

Some uses reported in the CDPR PUR database may be different than those considered in
the assessment. The uses considered in this risk assessment represent all currently
registered uses according to a review of all current labels. No other uses are relevant to
this assessment. Any other reported use, such as may be seen in the CDPR PUR database,
represent either historic uses that have been canceled, mis-reported uses, or mis-use.
Historical uses, mis-reported uses, and misuse are not considered part of the federal
action and, therefore, are not considered in this assessment.

The total pounds of malathion applied in California varies greatly between uses according
to the CDPR PUR data set (2001 - 2005). Of the 139 use categories for which malathion
was applied, 2 crops (alfalfa and strawberries) accounted for 48% of the total California
malathion usage between 2001 and 2005 (Figure 1). Including an additional eight crops
(head lettuce, walnut, leaf lettuce, celery, orange, date, lemon, and broccoli) accounts for
almost 80% of the total California malathion usage. The combined usage of the 75 crops
with the lowest average pounds applied per year only account for slightly less than 1% of
the total California malathion usage.

7	United States Depart of Agriculture (USDA), National Agricultural Statistics Service (NASS) Chemical
Use Reports provide summary pesticide usage statistics for select agricultural use sites by chemical, crop
and state. See http://www.usda.gOv/nass/pubs/estindxl.htm#agchem.

8	(www.doane.com: the full dataset is not provided due to its proprietary nature)

9	The California Department of Pesticide Regulation's Pesticide Use Reporting database provides a census
of pesticide applications in the state. See http://www.cdpr.ca.gov/docs/pur/purmain.htm.

25


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c
#o

"s

a

&
CJ

a.

a.

Q

es

es
U

Alfalfa
Strawberry
Lettuce, Head
Walnut
Lettuce, Leaf
Celery
Orange
Date
Lemon
Broccoli

N-Outdr Plants In Containers
Onion, Dry
Regulatory Pest Control
Bermudagrass
Tomato, Processing
Cotton
Wheat
Grape, Wine
Chinese Cabbage (Nappa)
Forage Hay/Silage
Bean, Dried
Tangerine
Raspberry
Onion, Green
Garlic
Carrot
Avocado
Grape
Blackberry
Peas

Bean, Succulent
Corn, Human Consumption

Spinach
Barley
Pumpkin
Kale

Pepper, Fruiting
Rice, Wild
Fig

Cauliflower
Bok Choy
N-Outdr Transplants
Tomato

N-Grnhs Plants In Containers
Cherry
Canola (Rape)

Endive (Escarole)
Gai Lon
Rice
Squash
Unknown
Squash, Summer
Cucumber
Corn (Forage - Fodder)
Bean, Unspecified
Watercress
N-Grnhs Flower
Grapefruit
N-Outdr Flower
Tangelo
Mustard
Wheat (Forage - Fodder)
Potato
Asparagus
Cantaloupe
Oat
Citrus
Mint
Beet
Pastureland
Turnip
Christmas Tree
Blueberry
Swiss Chard
Watermelon
Sweet Potato
Oat (Forage - Fodder)
Radish
Pear
Collard
Chinese Greens
Animal Premise
N-Grnhs Transplants
Clover
Nectarine
Almond
Peach
Leek

Uncultivated Non-Ag
Sorghum (Forage - Fodder)
Pecan
Rangeland

Okra

Rappini (Broccoli Rabe)
Eggplant
Safflower
Fennel
Zucchini
Shallot
Arrugula
Apple
Sudangrass
Tomatillo
Brussel Sprout
Pepper (Spice)
Vertebrate Control
Mizuna
Melon
Parsley
Livestock
Grass Seed
Parsnip
Uncultivated Ag.
Kohlrabi
Lime
Sorghum/Milo
Commodity Fumigation
Leafy Vegetables

Tropical/Subtropical Fruit
Olive
Prune
Vegetable
Apricot
Structural Pest Control
Winter Squash
Chive
Quince
Plum

Landscape Maintenance
Mango
Kumquat
Research Commodity
Gai Choy
Buildings/Non-Ag. Outdoor
Mushroom
Sugarbeet
Rights of Way
Daikon

1000 10000 100000 1E+06	1 0 1 00 1 000 1 0000

Total Pounds of Malathion Applied in California (2001 - 2005)

0.1 1 10 100 1000

Figure 1. Total pounds of malathion applied for all uses identified in the California Dept. of Pesticide Regulation database from 2001 through 2005.

26


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Based on data reported in the CA PUR database, malathion application varies temporally
within years in California (Figure 2). Months with the lowest and highest pounds of
malathion applied per month across California are December and August, respectively.
Therefore in general, the breeding/egg mass and tadpole phases of the CRLF life cycle
tend to occur when less malathion is being applied, while the young juvenile phases
occur when more malathion is being applied.

a

o

- R

4) •-

ft C

u

*o ,©

a.

s u

<	s

S3	X,

.2	"J

!3	°

® o

"o8 '

O

¦s
s
s

o

CL.

200
180
160
140
120
100
80
60
40
20
0

Young Juveniles

¦ 2001

~	2002
H2003

~	2004
B2005

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

Figure 2. Comparison of phases of the California Red-legged Frog (CRLF) life cycle to total
malathion usage in California by month for years 2001 through 2005.

Fifty-three of California's 58 counties reported some usage of malathion from 2001 to
2005. Of the malathion applied in California over this time period, almost 93% was
applied in 21 counties (Figure 3). Highest usage (greater than 6% of total California use
in each county) was reported in Monterey (14,200 lbs. malathion per year), Imperial
(13,700), Kern (12,900), Santa Barbara (10,100), Fresno (7600), and Riverside (6600)
counties.

27


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County

Figure 3. Average percent contribution of counties to total California malathion usage based on 2002
through 2005 California Dept. of Pesticide Regulation Pesticide Use Reporting (CDPR PUR) use data
(33 counties contributing less than 1% each are not shown).

2.5 Assessed Species

The CRLF was federally listed as a threatened species by USFWS effective June 24,
1996 (USFWS 1996). It is one of two subspecies of the red-legged frog and is the largest
native frog in the western United States (USFWS 2002). Final critical habitat for the
CRLF was designated by USFWS on April 13, 2006 (USFWS 2006; 71 FR 19244-
19346). A brief discussion of distribution, reproduction, diet, and habitat requirements
follows, with more detailed information provided in Attachment 1.

Distribution: The CRLF is endemic to California and Baja California (Mexico) and
historically inhabited 46 counties in California, including the Central Valley and both the
coastal and interior mountain ranges (USFWS 1996). Spatially, its range has been
reduced by approximately 70%, and it currently inhabits 22 counties in California
(USFWS 1996). Additionally, the species has an elevation range of near sea level to
1,500 meters (5,200 feet) (Jennings and Hayes 1994); however, nearly all of the known
populations have been documented below 1,050 meters (3,500 feet) (USFWS 2002).

Populations currently exist along the northern California coast, northern Transverse
Ranges (USFWS 2002), foothills of the Sierra Nevada (5-6 populations), and in southern
California south of Santa Barbara (two populations) (Fellers 2005a). A total of 243
streams or drainages are believed to be currently occupied by the species, with the
greatest numbers in Monterey, San Luis Obispo, and Santa Barbara counties (USFWS
1996). Occupied drainages or watersheds include all bodies of water that support CRLF

28


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{i.e., streams, creeks, tributaries, associated natural and artificial ponds, and adjacent
drainages), and habitats through which CRLF can move {i.e., riparian vegetation,
uplands) (USFWS 2002).

The distribution of CRLF within California is addressed in this assessment using four
categories of location. Three of these categories were designated by the USFWS in the
recovery plan (recovery units, core areas, and designated critical habitat). The fourth
category is known occurrences as reported in the California Natural Diversity Database
(CNDDB) (Figure 4). Recovery units are large areas defined at the watershed level that
have similar conservation needs and management strategies. The recovery unit is
primarily an administrative designation, and land area within the recovery unit boundary
is not exclusively CRLF habitat. Core areas are smaller areas within the recovery units
that comprise portions of the species' historic and current range and have been
determined by USFWS to be important in the preservation of the species. Designated
critical habitat is generally contained within the core areas, although a number of critical
habitat units are outside the boundaries of core areas, but within the boundaries of the
recovery units. Additional information on CRLF occurrences from the CNDDB is used to
cover the current range of the species not included in core areas and/or designated critical
habitat, but within the recovery units. For purposes of this assessment, designated critical
habitat, currently occupied (post-1985) core areas, and additional known occurrences of
the CRLF from the CNDDB are considered the range of the species.

Recovery Units: Eight recovery units have been established by USFWS for the CRLF.
These areas are considered essential to the recovery of the species. The status of the
CRLF "may be considered within the smaller scale of the recovery units, as opposed to
the statewide range" (USFWS 2002). Recovery units reflect areas with similar
conservation needs and population status, and therefore, similar recovery goals. The eight
recovery units are delineated by watershed boundaries defined by US Geological Survey
hydrologic units and are limited to the elevation maximum for the species of 1,500 m
above sea level.

Core Areas: USFWS has designated 35 core areas to focus recovery efforts. The core
areas, which are distributed throughout portions of the historic and current range of the
species, are intended to provide for long-term viability of existing populations and
reestablishment of populations within the historic range. These areas were selected
because they: 1) contain existing viable populations; or 2) they contribute to the
connectivity of other habitat areas (USFWS 2002). Core area protection and enhancement
are vital for maintenance and expansion of the CRLF's distribution and population
throughout its range.

29


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Figure 4. California Red-legged Frog (CRLF) distribution within the United States.

30


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Designated Critical Habitat. Critical habitat was designated for the CRLF on April 13,
2006 (USFWS 2006; 71 FR 19244-19346). Critical habitat was selected for the species
based on areas: 1) that are occupied by CRLF; 2) where source populations of CRLF
occur; 3) that provide connectivity between source populations; and 4) that are
ecologically significant. Designation of critical habitat is based on habitat areas that
provide essential life cycle needs of the species or areas that contain primary constituent
elements (PCEs) (as defined in 50 CFR 414.12(b)) The designated critical habitat areas
for the CRLF are considered to have the following PCEs that justify critical habitat
designation (USFWS 2006):

•	Aquatic breeding habitat;

•	Non-breeding aquatic habitat;

•	Upland habitat; and

•	Dispersal habitat.

Critical habitat does not include certain areas where existing management is sufficient for
CRLF protection. For the CRLF, all designated critical habitat units contain all four PCEs
and were occupied by the CRLF at the time of listing.

USFWS has established adverse modification standards for designated critical habitat
(USFWS 2006). Activities that may destroy or adversely modify critical habitat are those
that alter the PCEs and jeopardize the continued existence of the species. For the CRLF
specifically, these include, but are not limited to, the following:

•	Alteration of water chemistry or temperature;

•	Increased sedimentation;

•	Alteration of channel or pond morphology;

•	Elimination of upland foraging areas;

•	Introduction of non-native species; and

•	Degradation of prey base.

The critical habitat designation includes a special rule exempting routine ranching
activities associated with livestock ranching from incidental take prohibitions. The
purpose of this exemption is to promote the conservation of rangelands, which could be
beneficial to the CRLF, and to reduce the rate of conversion to other land uses that are
incompatible with CRLF conservation.

Other Known CRLF Occurrences: The CNDDB10 provides location and natural history
information on species found in California. It is the best available information for
historical and current species location sightings (Figure 4).

10 See: http ://www. dfg. ca. gov/bdb/html/cnddb info .html for additional information on the CNDDB.

31


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2.6 Action Area

For listed species assessment purposes, the action area is considered to be the area
affected directly or indirectly by the federal action and not merely the immediate area
involved in the action (50 CFR 402.02). It is recognized that the overall action area for
the national registration of malathion is likely to encompass considerable portions of the
United States based on the large array of agricultural uses and non-agricultural uses.
However, the scope of this assessment limits consideration of the overall action area to
those portions that may be applicable to the protection of the CRLF and its designated
critical habitat within the state of California. Deriving the geographical extent of this
portion of the action area is the product of consideration of the types of effects that
malathion may be expected to have on the environment, the exposure levels to malathion
that are associated with those effects, and the best available information concerning the
use of malathion and its fate and transport within the state of California.

The definition of action area requires a stepwise approach that begins with an
understanding of the federal action. The federal action is defined by the currently labeled
uses for malathion. An analysis of labeled uses and review of available product labels
was completed. This analysis indicates that, for malathion, the following uses are
considered as part of the federal action evaluated in this assessment:

All outdoor uses that result in spray drift or run-off exposure are included in the
initial area of concern. Indoor uses are not considered part of the action area since
exposure of the CRLF is unlikely.

After a determination of which uses will be assessed, an evaluation of the potential
"footprint" of the use pattern should be determined. This "footprint" represents the initial
area of concern and is based on available land cover data for labeled outdoor uses. Local
land cover data available for the state of California were analyzed to refine the
understanding of potential malathion use. The initial area of concern is defined as all land
cover types that represent the labeled uses described above. Because malathion uses can
occur on all of these land cover types, the initial area of concern is considered to be the
entire state of California.

Once the initial area of concern is defined, the next step is to compare the extent of that
area with the results of the screening level risk assessment. The screening level risk
assessment will define which taxa, if any, are predicted to be exposed at concentrations
above the Agency's Levels of Concern (LOC). The screening level assessment includes
an evaluation of the environmental fate properties of malathion to determine which routes
of transport are likely to have an impact on the CRLF.

LOC exceedances are used to describe how far effects may be seen from the initial area
of concern. Factors considered include: spray drift, downstream run-off, atmospheric
transport, etc. Because LOC exceedances would be expected to occur on all land cover
types, the final action area is determined to be the entire state of California.

32


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2.7 Assessment Endpoints and Measures of Ecological Effect

Assessment endpoints are defined as "explicit expressions of the actual environmental
value that is to be protected."11 Selection of the assessment endpoints is based on valued
entities (e.g., CRLF, organisms important in the life cycle of the CRLF, and the PCEs of
its designated critical habitat), the ecosystems potentially at risk (e.g., water bodies,
riparian vegetation, and upland and dispersal habitats), the migration pathways of
malathion (e.g., runoff, spray drift, etc.), and the routes by which ecological receptors are
exposed to malathion related contamination (e.g., direct contact, etc).

Assessment endpoints for the CRLF include direct toxic effects on the survival,
reproduction, and growth of the CRLF, as well as indirect effects, such as reduction of
the prey base and/or modification of its habitat. In addition, potential modification of
critical habitat is assessed by evaluating potential effects to PCEs, which are components
of the habitat areas that provide essential life cycle needs of the CRLF. Each assessment
endpoint requires one or more "measures of ecological effect," defined as changes in the
attributes of an assessment endpoint or changes in a surrogate entity or attribute in
response to exposure to a pesticide. Specific measures of ecological effect are generally
evaluated based on acute and chronic toxicity information from registrant-submitted
guideline tests that are performed on a limited number of organisms. Additional
ecological effects data from the open literature are also considered.

A complete discussion of all the toxicity data available for this risk assessment, including
resulting measures of ecological effect selected for each taxonomic group of concern, is
included in Section 4 of this document. A summary of the assessment endpoints and
measures of ecological effect selected to characterize potential assessed direct and
indirect CRLF risks associated with exposure to malathion is provided in Table 5.

Table 5 Assessment endpoints and measures of ecological effects.

Assessment Endpoint

Measures of Ecological Effects

Aquatic Phase (Eggs, larvae, tadpoles, juveniles, and adults)3

Direct Effects

1. Survival, growth, and reproduction of CRLF

Acute malathion: Indian bullfrog larval LC500.59 |ig/L
Acute maloxon: Indian bullfrog larval LC500.59 |ig/L
adjusted for oxon potency (0.59/92.9)

Chronic malathion: Fish ACR 40.6 applied to acute
endpoint (0.59/40.6)

Chronic maloxon: as above divided by 92.9

11 From U.S. EPA (1992). Framework for Ecological Risk Assessment. EPA/630/R-92/001.

33


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Assessment Endpoint

Measures of Ecological Effects

Indirect Effects and Critical Habitat Effects

2. Survival, growth, and reproduction of CRLF
individuals via indirect effects on aquatic prey food
supply (i.e., fish, freshwater invertebrates, and non-
vascular plants)

Acute malathion: rainbow trout LC50 4 |ig/L

Acute maloxon: rainbow trout LC50 4 |ig/L adjusted for

oxon potency (4/92.9)

Chronic malathion: Fish ACR 40.6 applied to acute
endpoint (4/40.6)

Chronic maloxon: as above divided by 92.9
Acute malathion: daphnidEC500.01 |ig/L
Acute maloxon: daphnidEC500.01 |ig/L adjusted for
oxon potency (0.01/92.9)

Chronic malathion: Invertebrate ACR 392 applied to
acute endpoint (0.01/392)

Chronic maloxon: as above divided by 92.9
Non-vascular plant (freshwater algae) acute EC50 2040
|ig/L and NOEC 500 |ig/L (malathion and oxon
equipotent)

3. Survival, growth, and reproduction of CRLF
individuals via indirect effects on habitat, cover,
and/or primary productivity (i.e., aquatic plant
community)

Malathion and oxon assumed equipotent
Vascular plant acute EC50 not available, NOAEC
24,065 |ig/L for acute endpoint
Non-vascular plant (freshwater algae) acute EC50 2040
|ig/L and NOEC 500 |ig/L

4. Survival, growth, and reproduction of CRLF
individuals via effects to riparian vegetation

No adverse effects assumed based on available toxicity
data

Terrestrial Phase (Juveniles and adults)

Direct Effects

5. Survival, growth, and reproduction of CRLF
individuals via direct effects on terrestrial phase
adults and juveniles'3

Malathion acute: Ring-necked pheasant LD501485
mg/kg-bw

Maloxon acute: Acute malathion endpoint divided by
92.9 potency adjustment (1485/92.9)

Malathion chronic: Bobwhite quail chronic NOAEC
110 mg/kg-diet

Maloxon chronic: malathion acute endpoint divided by
92.9 potency adjustment (110/92.9)

Indirect Effects and Critical Habitat Effects

6. Survival, growth, and reproduction of CRLF
individuals via effects on terrestrial prey (i.e.,
terrestrial invertebrates, small mammals, and frogs)

Invertebrate: alfalfa leafcutterbee 96hrLD50 0.000285
Hg/animal assumed equipotency malathion and
maloxon

Malathion acute: rat LD50 3400 mg/kg-bw

Maloxon acute: malathion acute endpoint divided by

92.9 potency (3400/92.9)

Malathion chronic: rat reproduction NOAEC 240

mg/kg/day

Maloxon chronic: malathion chronic endpoint divided

by 92.9 potency (240/92.9)

Malathion acute: Ring-necked pheasant LD501485

mg/kg-bw

Maloxon acute: Acute malathion endpoint divided by
92.9 potency adjustment (1485/92.9)

Malathion chronic: Bobwhite quail chronic NOAEC
110 mg/kg-diet

Maloxon chronic: malathion acute endpoint divided by
92.9 potency adjustment (110/92.9)

34


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Assessment Endpoint

Measures of Ecological Effects

7. Survival, growth, and reproduction of CRLF
individuals via indirect effects on habitat (i.e.,
riparian vegetation)

No adverse effects assumed based on available toxicity
data

a Adult frogs are no longer in the "aquatic phase" of the amphibian life cycle; however, submerged adult
frogs are considered "aquatic" for the purposes of this assessment because exposure pathways in the water
are considerably different that exposure pathways on land.
b Birds are used as surrogates for terrestrial phase amphibians.

Measures of effect and assessment endpoints defined for indirect effects also apply to
critical habitat. Assessment endpoints used for the analysis of designated critical habitat
are based on the adverse modification standard established by USFWS (2006).

Assessment endpoints and measures of ecological effect selected to characterize potential
modification to designated critical habitat associated with exposure to malathion are
listed below. Adverse modification to the critical habitat of the CRLF includes the
following, as specified by USFWS (2006):

1.	Alteration of water chemistry/quality including temperature, turbidity, and
oxygen content necessary for normal growth and viability of juvenile and
adult CRLF.

2.	Alteration of chemical characteristics necessary for normal growth and
viability of juvenile and adult CRLF.

3.	Significant increase in sediment deposition within the stream channel or pond
or disturbance of upland foraging and dispersal habitat.

4.	Significant alteration of channel/pond morphology or geometry.

5.	Elimination of upland foraging and/or aestivating habitat, as well as dispersal
habitat.

6.	Introduction, spread, or augmentation of non-native aquatic species in stream
segments or ponds used by the CRLF.

7.	Alteration or elimination of the CRLF's food sources or prey base.

Some components of these PCEs are associated with physical abiotic features (e.g.,
presence and/or depth of a water body, or distance between two sites), which are not
expected to be measurably altered by use of pesticides.

2.8 Risk Assessment Conceptual Model

Risk hypotheses are specific assumptions about potential adverse effects (i.e., changes in
assessment endpoints) and may be based on theory and logic, empirical data,
mathematical models, or probability models (U.S. EPA, 1998). For this assessment, the
risk is stressor-linked, where the stressor is the release of malathion to the environment.

2.8.1 Risk Hypotheses
The following risk hypotheses are presumed for this listed species assessment:

• Labeled uses of malathion within the action area may directly affect the CRLF by
causing mortality or by adversely affecting growth or fecundity;

35


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•	Labeled uses of malathion within the action area may indirectly affect the CRLF
by reducing or changing the composition of food supply;

•	Labeled uses of malathion within the action area may indirectly affect the CRLF
or modify designated critical habitat by reducing or changing the composition of the
aquatic plant community in the ponds and streams comprising the species' current range
and designated critical habitat, thus affecting primary productivity and/or cover;

•	Labeled uses of malathion within the action area may indirectly affect the CRLF
or modify designated critical habitat by reducing or changing the composition of the
terrestrial plant community {i.e., riparian habitat) required to maintain acceptable water
quality and habitat in the ponds and streams comprising the species' current range and
designated critical habitat;

•	Labeled uses of malathion within the action area may modify the designated
critical habitat of the CRLF by reducing or changing breeding and non-breeding aquatic
habitat (via modification of water quality parameters, habitat morphology, and/or
sedimentation);

•	Labeled uses of malathion within the action area may modify the designated
critical habitat of the CRLF by reducing the food supply required for normal growth and
viability of juvenile and adult CRLF;

•	Labeled uses of malathion within the action area may modify the designated
critical habitat of the CRLF by reducing or changing upland habitat within 200 ft of the
edge of the riparian vegetation necessary for shelter, foraging, and predator avoidance.

•	Labeled uses of malathion within the action area may modify the designated
critical habitat of the CRLF by reducing or changing dispersal habitat within designated
units and between occupied locations within 0.7 mi of each other that allow for
movement between sites including both natural and altered sites which do not contain
barriers to dispersal.

•	Labeled uses of malathion within the action area may modify the designated
critical habitat of the CRLF by altering chemical characteristics necessary for normal
growth and viability of juvenile and adult CRLF.

2.8.2 Assessment Diagrams

The assessment diagrams are graphic representations of the structure of the risk
assessment. It specifies the stressor (malathion) release mechanisms, biological receptor
types, and effects endpoints of potential concern. Exposure routes shown in dashed lines
are not quantitatively considered because the resulting exposures are expected to be so
low as not to cause adverse effects to the CRLF.

The conceptual model for direct effects to the aquatic phase of the CRLF's life cycle
from malathion uses is shown in Figures 5. Long-range atmospheric transport is not
expected due to the non-volatility and non-persistent nature of malathion. Groundwater
transport is considered quantitatively through PRZM model, but is considered to be a
relatively minor source due to the non-persistence of malathion, even when its mobility in

36


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soil is considered. Lastly, adverse affects of malathion to riparian terrestrial vegetation
and aquatic vegetation are likely to be negligible because malathion is an insecticide used
to protect a wide variety of crops to which it is directly applied and its mechanism of
action (Section 2.4.2) is not expected to affect vegetation. The operative routes of
exposure will be spray drift at the time of application and run-off due to precipitation
within a few days of application.

Stressor

Source

Exposure
Media

Receptors

Attribute
Change

Malathion applied to use site

I

I

| Spray drift | | Runoff |



' i

r



Surface water/





Sediment



I

| Soil \-

Groundwater

	*.	

Long range
atmospheric
transport

Wet/dry deposition

I

Uptake/gills
or integument

Uptake/gills
or integument

t^u

Aquatic Animals

Invertebrates
Vertebrates

Uptake/cell,
roots^leaves

Aquatic Plants

Non-vascular
Vascular

~

Ingestion

Red-legged Frog

Eggs Juveniles
Larvae Adult
Ladpoles

Individual organisms

Reduced survival
Reduced growth
Reduced reproduction

T

Ingestion

Food chain

Reduction in algae
Reduction in prey

Riparian plant

terrestrial
exposure
pathways see
Figure 8

Habitat integrity

Reduction in primary productivity
Reduced cover
Community change

Figure 5. Conceptual model for direct malathion effects on the aquatic phase of the California Red-
Legged Frog. Compartments and pathways in dashed lines are considered possible but not of sufficient
significance to warrant quantification in the assessment.

The conceptual model for direct effects to the terrestrial phase of the CRLF's life cycle
from malathion uses is shown in Figures 6. Again, long-range atmospheric transport is
not expected due to the non-volatility and non-persistent nature of malathion, and adverse
affects of malathion to vegetation are not expected. The operative routes of exposure will
be through direct application and spray drift at the time of application.

37


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Stressor

Source

Exposure
Media

Malathion applied to use site

-| Spray drift |-

I

Dermal uptake/Ingestion

—a I Runoff I

I I

Soil

	T.	

Long range
atmospheric
transport

Terrestrial/riparian plants
grasses/forbs, fruit, seeds
(trees, shrubs)

Root uptake ^ ^
	 Wet/dry deposition

~ Ingestion

-~ Ingestion

tion I

ill

Ingestion

I

Receptors

Attribute
Change

Red-legged Frog

Juvenile
Adult

Individual organisms

Reduced survival
Reduced growth
Reduced reproduction

Ingestion M	1 Mammals I

_2zr

Food chain

Reduction in prey

Habitat integrity

Reduction in primary productivity
Reduced cover
Community change

Figure 6. Conceptual model for malathion effects on the terrestrial phase of the California Red-
legged Frog. Compartments and pathways in dashed lines are considered possible but not of sufficient
significance to warrant quantification in the assessment.

The conceptual model for indirect effects to the aquatic phase of the CRLF's critical
habitat from malathion uses is shown in Figures 7. Long-range atmospheric transport is
not expected due to the non-volatility and non-persistent nature of malathion.
Groundwater transport is considered quantitatively through PRZM model, but is
considered to be a relatively minor source due to the non-persistence of malathion, even
when its mobility in soil is considered. Lastly, adverse affects of malathion to riparian
terrestrial vegetation and aquatic vegetation are likely to be negligible because malathion
is an insecticide used to protect a wide variety of crops to which it is directly applied and
its mechanism of action (Section 2.4.2) is not expected to affect vegetation. The operative
routes of exposure will be spray drift at the time of application and run-off due to
precipitation within a few days of application.

38


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Stressor

Receptors

Attribute
Change

Malathion applied to use site

I

I

Source

Spray drift | | Runoff |



1

r i

r

Exposure



Surface water/



Media



Sediment



I

| Soil \-

Groundwater

	T.	

Long range
atmospheric
transport

Wet/dry deposition

Uptake/gills
or integument

Uptake/gills
or integument

t^u

Aquatic Animals

Invertebrates
Vertebrates

Uptake/cell,
roots^leaves

Aquatic Plants

Non-vascular
Vascular

Red-legged Frog

Eggs Juveniles
Larvae Adult
Ladpoles

I

Individual organisms

Reduced survival
Reduced growth
Reduced reproduction

Riparian plant

terrestrial
exposure
pathways see
Figure 8

Food chain

Reduction in algae
Reduction in prey

Habitat integrity

Reduction in primary productivity
Reduced cover
Community change

Figure 7. Conceptual model for malathion effects on the aquatic component of California Red-legged
Frog critical habitat. Compartments and pathways in dashed lines are considered possible but not of
sufficient significance to warrant quantification in the assessment.

The conceptual model for indirect effects to the terrestrial phase of the CRLF's critical
habitat from malathion uses is shown in Figures 8. Again, long-range atmospheric
transport is not expected due to the non-volatility and non-persistent nature of malathion,
and adverse affects of malathion to vegetation are not expected. The operative routes of
exposure will be through direct application and spray drift at the time of application.

39


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Stressor

Source

Exposure
Media

Malathion applied to use site

-| Spray drift |-

I

Dermal uptake/Ingestion

—a I Runoff I

I I

Soil

	T.	

Long range
atmospheric
transport

Terrestrial/riparian plants
grasses/forbs, fruit, seeds
(trees, shrubs)

Ingestion

I

Receptors

Attribute
Change

Red-legged Frog

Juvenile
Adult

Individual organisms

Reduced survival
Reduced growth
Reduced reproduction

-~ Ingestion j
Ingestion M	| Mammals |

Root uptake ^ ^
	 Wet/dry deposition

-~Ingestion

Food chain

Reduction in prey

Habitat integrity

Reduction in primary productivity
Reduced cover
Community change

Figure 8. Conceptual model for malathion effects on the terrestrial component of California Red-
legged Frog critical habitat. Compartments and pathways in dashed lines are considered possible but not
of sufficient significance to warrant quantification in the assessment.

2.9 Analysis Plan

Analysis of risks to the California Red-Legged Frog (both direct and indirect) and to its
critical habitat will be assessed consistent with the Overview Document (USEPA, 2004)
and Agency guidance for ecological risk assessments (USEPA 1998).

There are a number of labeled uses for malathion for indoor applications. These
applications have been considered. There is no exposure pathway from indoor
applications to the CRLF or its habitat and therefore, indoor applications are determined
to have No Effect on the CRLF.

2.9.1 Exposure Analysis

Direct effects to the aquatic phase CRLF will be assessed by comparing modeled surface
water exposure concentrations of malathion and its impurity/degradate maloxon to acute
and chronic effect concentrations for aquatic phase amphibians from laboratory studies
(see the Effects Analysis section below). Effects to aquatic dietary food resources
(aquatic invertebrates, algae) of the aquatic phase CRLF or effects to aquatic habitat that
support the CRLF will also be assessed by comparing modeled surface water exposure

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concentrations of total malathion residues to laboratory established effect levels
appropriate for the taxa.

Surface water concentrations of malathion and maloxon will be quantified using PRZM-
EXAMS. The standard EXAMS water body of 2 meters maximum depth, and 20,000
cubic meters volume, will be used. Because malathion is applied by numerous application
methods, the model accounts for loading of malathion into the surface water via spray
drift, run-off and erosion. Agricultural scenarios appropriate for labeled malathion uses
will be used to account for local soils, weather and growing practices which impact the
magnitude and frequency of malathion and maloxon loading to the surface water.
Maximum labeled application rates, with maximum number of applications and shortest
intervals, will be used to help define (1) the Action Area within California for the Federal
Action and (2) for evaluating effects to the CRLF.

Concentrations of malathion/maloxon estimated by PRZM-EXAMS represent
malathion/maloxon loading in water bodies adjacent to any treated field and assume that
the concentration applies to any water body within the treated area.

Risks to the terrestrial phase CRLF will be assessed by comparing modeled exposure to
effect concentrations from laboratory studies. Exposure in the terrestrial phase will be
quantified using the TREX model, which automates the calculation of dietary exposure
according to the Hoerger-Kenaga nomogram, as modified by Fletcher (1994). The
nomogram tabulates the 90th and 50th percentile exposure expected on various classes of
food items, and scales the exposure (in dietary terms) to the size and daily food intake of
several size classes of birds and mammals. Birds are also used as surrogates to represent
reptiles and terrestrial-phase amphibians. A foliar decay half-life of 5.5 days, the
maximum for malathion found in Willis and McDowell (1987) will be substituted for the
default 35-day value. Effects from maloxon are not considered quantitatively as LOC is
expected to be exceeded for parent malathion.

2.9.2 Effects Analysis

As previously discussed in Section 2.7, assessment endpoints for the frog include direct
toxic effects on survival, reproduction, and growth of the species itself, as well as indirect
effects, such as reduction of the prey base and/or modification of CRLF habitat. Direct
effects to the CRLF are based on toxicity information for freshwater fish and birds, which
are generally used as a surrogate for aquatic and terrestrial phase amphibians,
respectively. The open literature will be screened also for available frog toxicity data.
Indirect effects to the CRLF are assessed by looking at available toxicity information
relative to the frog's prey items and habitat requirements (freshwater invertebrates,
freshwater vertebrates, aquatic plants, terrestrial invertebrates, terrestrial vertebrates, and
terrestrial plants). Both guideline and open literature toxicity data will be identified and
evaluated for use in determining RQ values.

Toxicity studies for malathion degradates (where available) will be discussed for
exposure to the aquatic phase of the CRLF and incorporated into this risk assessment.

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2.9.3 Action Area Analysis

The Action Area for the federal action is the geographic extent of exceedence of Listed
species Levels of Concern (LOC) for any taxon or effect (plant or animal, acute or
chronic, direct or indirect) resulting from the maximum label-allowed use of malthion. To
define the extent of the Action Area, the following exposure assessment tools will be
used: PRZM-EXAMS, TREX, AgDrift, and ArcGIS, a geographic information system
(GIS) program. Other tools may be used as required if these are inadequate to define the
maximum extent of the Action Area.

To determine the downstream extent of the Action area for any aquatic effects, malathion
residues are also estimated for downstream from the treated areas by assuming dilution
with stream water (derived from land area) from unaffected sources propagating
downstream, until a point is reached beyond which there are no relevant LOC
exceedances. Once the distribution of predicted stream water concentrations is obtained,
it is further processed using a model that calculates expected dilution in the stream
according to contributing land area. As the land area surrounding the field on which
malathion is applied is enlarged, it encompasses a progressively greater drainage area; in
effect, a progressively larger 'sub-watershed' is created, with a concomitant increase in
dilution at the drainage point. This drainage point moves down-gradient along the stream
channel as the sub-watershed is expanded. At a certain point the predicted stream
concentrations will fall below the LOC. The area below this point is then assumed not to
be at risk, with the upstream areas (up to the initial application area) assumed to present
the potential for (direct and indirect) impact on the RLF. Additional malathion inputs
within the same watershed will cause the area bounded by (that is, within) the LOC to
increase, extending the length of stream that is likely to be impacted.

In order to determine the extent of the action area downstream from the initial area of
concern, the Agency will need to complete the screening level risk assessment. Once all
aquatic risk quotients (RQs) are calculated, the Agency determines which RQ to level of
concern (LOC) ratio is greatest for all aquatic organisms (plant and animal). For example,
if both fish and aquatic plants have the same RQ of 1, the fish RQ to LOC ratio (1/0.05)
would be greater than for plants (1/1). Therefore, the Agency would identify all stream
reaches downstream from the initial area of concern where the PCA (percent cropped
area) for the land uses identified for malathion are greater than 1/20, or 5%. All streams
identified as draining upstream catchments greater than 5% of the landclass of concern,
will be considered part of the action area.

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3. Exposure (Fate) Assessment

Exposure is the contact or co-occurrence between a stressor (malathion) and a receptor
(the CRLF and the habitat upon which it depends). The objective of exposure assessment
is to describe exposure in terms of intensity, space, and time in units that can be
combined with the effects assessment (USEPA 1998) presented in section 4.

3.1 Label Application Rates and Intervals

There are many currently permitted uses for malathion listed on pesticide labels. Each use
will potentially provide a different exposure of CRLF to malathion and/or its degradates
in terms of intensity, space, and time.

EFED uses models to estimate the intensity and duration of exposure of organisms to
chemicals concentrations in the environment that are appropriate for locations at which
the exposure of malathion and/or its degradates will co-occur with the CRLF. Because it
would be unwieldy and impractical to evaluate each individual malathion use, uses that
produce similar exposures (in terms of intensity, space, and time) are grouped together
and evaluated as a single exposure scenario. In this way, the large number of malathion
uses that vary greatly in terms of potential exposure can be grouped into a more
manageable number of exposure scenario groups (60) that relatively accurately reflect the
exposure expected from each of the label-permitted malathion uses.

Because the purpose of the exposure assessment is to determine if the currently permitted
label uses do not harm the CRLF, worst case, yet realistic, scenarios (conservative
assumptions) are developed for each use. However as shown in subsequent sections, the
paucity of information given on many malathion labels regarding the time of year when
malathion can be applied, the number of applications per year or crop-cycle, and the
minimum time until additional malathion treatments could be applied required that
assumptions be made in the design of these "realistic, yet conservative, scenarios".

3.1.1 Application Rates

Maximum application rates were used in each scenario in order to ensure the scenarios
were conservative (protective of CRLF). However, up to three different kinds of
maximum application rates were identified for each scenario group in Table 6 - home
and garden rate (labeled "H&G" in the following tables), aerial (labeled "air"), and rates
that were not considered to be a home and garden or aerial rate (labeled "other"). Home
and garden malathion uses often have application rates when converted to lbs. ai/A that
are much higher than the corresponding agricultural uses, but are applied to much smaller
areas (and therefore, assumed to be applied to only a portion of the watershed of the
standard pond that EFED uses to assess aquatic impacts). The maximum home and
garden rates from each crop/site were evaluated collectively and used to develop the
residential exposure scenario. Air uses are those uses for which EFED policy applies a
default spray drift fraction of 5% for modeling purposes. These uses include aircraft and

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air blast application methods. Other uses are those uses for which EFED policy applies a
default spray drift fraction of 1% for modeling purposes.

Table 6. A partial listing" of applicable labels and maximum aerial (air), home and Garden (H&G),
and non-aerial (other) for each crop/site grouping.		

Scenario Group. Crop/Site

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

Agricultural Uses

1. Alfalfa, Clover, Lespedeza,
Lupine, Trefoil, and Vetch

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Drexel Malathion 50% Emulsifiable (19713-330),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Malathion Insecticide (ULV)
(66330-219), Malathion ULV (19713-540), Malathion ULV
Concentrate Insecticide (34704-18), Prentox 51b Malathion
Spray (655-777), ProKil Malathion 25-WP (10163-61),
ProKil Malathion 8E (10163-21), and ProKil Malathion ULV
(10163-44)

Air: 2
Other: 2
H&G: 2

2. Macadamia Nut (Bushnut)

Cythion 8 Aquamul (34704-474), Malathion 8EC (66330-
248), Prentox 51b Malathion Spray (655-777), and ProKil
Malathion 8E (10163-21)

Air: 15
Other: 15
H&G: 15

3. Pecan and Walnut
(English/Black)

Atrapa 5E (4787-44), Clean Crop Malathion 57EC (34704-
108), Clean Crop Malathion 8 EC Insecticide (34704-119),
Cythion 8 Aquamul (34704-474), Drexel Malathion 5EC
(19713-217), Malathion 5EC (66330-220), Malathion 8EC
(66330-248), Malathion ULV Concentrate Insecticide
(CA83001200), Prentox 51b Malathion Spray (655-777), and
ProKil Malathion 8E (10163-21)

Air: 12.5
Other: 12.5
H&G: 12.5

4. Chestnut

Clean Crop Malathion 57EC (34704-108) and
Cythion 8 Aquamul (34704-474)

Air: 5
Other: 5
H&G: 5

5. Almond

Clean Crop Malathion 57EC (34704-108), Clean Crop
Malathion 8 EC Insecticide (34704-119), and Malathion ULV
Concentrate Insecticide (CA83001200)

Air: 1.25
Other: 4
H&G: 4

6. Date

Clean Crop Malathion 8 EC Insecticide (34704-119), Gowan
Malathion 5 Dust (10163-142), and Niagara Malathion 5 Dust
(34704-721)

Air: 1
Other: 2
H&G: 2

7. Filbert (Hazelnut)

Clean Crop Malathion 57EC (34704-108) and
Malathion ULV Concentrate Insecticide (CA83001200)

Air: .625
Other: .625
H&G: .625

8. Avocado

Atrapa 5E (4787-44), Clean Crop Malathion 8 EC Insecticide
(34704-119), Cythion 8 Aquamul (34704-474), Drexel
Malathion 5EC (19713-217), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Malathion ULV Concentrate
Insecticide (CA83001200), Prentox 51b Malathion Spray
(655-777), and ProKil Malathion 8E (10163-21)

Air: 9
Other: 9
H&G: 9

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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

9. Citrus, Citrus Hybrids other
than Tangelo, Grapefruit,
Kumquat, Lemon, Lime,
Orange, Tangelo, and
Tangerines

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Malathion ULV
Concentrate Insecticide (CA83001200), Prentox 51b
Malathion Spray (655-777), ProKil Malathion 25-WP
(10163-61), and ProKil Malathion 8E (10163-21)

Air: 25
Other: 25
H&G: 25

10. Amaranth - Chinese,
Broccoli (Unspecified,
Chinese, and Raab), Cabbage
(Unspecified and Chinese),
Canola\Rape, Cauliflower,
Collards, Corn Salad, Dock
(Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard
Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden
and Winter)

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), ProKil
Malathion 25-WP (10163-61), and ProKil Malathion 8E
(10163-21)

Air: 2.5
Other: 2.5
H&G: 25.8

11. Corn (Unspecified, Field,
Pop, and Sweet), and Millet
(Foxtail)

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Drexel Malathion 5EC (19713-217), Malathion 5EC
(66330-220), Malathion 8EC (66330-248), Malathion
Insecticide (ULV) (66330-219), Malathion ULV (19713-
540), Malathion ULV Concentrate Insecticide (34704-18),
Prentox 51b Malathion Spray (655-777), Prentox Malathion
57% E.C. (655-794), ProKil Malathion 25-WP (10163-61),
ProKil Malathion 8E (10163-21), and ProKil Malathion ULV
(10163-44)

Air: 1.5
Other: 1.5
H&G: 12.9

12. Cotton

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Drexel Malathion 50% Emulsifiable (19713-330),
Drexel Malathion 5EC (19713-217), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Malathion Insecticide
(ULV) (66330-219), Malathion ULV (19713-540), Malathion
ULV Concentrate Insecticide (34704-18), Prentox 51b
Malathion Spray (655-777), ProKil Malathion 25-WP
(10163-61), ProKil Malathion 8E (10163-21), and ProKil
Malathion ULV (10163-44)

Air: 4
Other: 4
H&G: 4

15. Apricot

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Malathion ULV
Concentrate Insecticide (CA83001200), Prentox 51b
Malathion Spray (655-777), ProKil Malathion 25-WP
(10163-61), and ProKil Malathion 8E (10163-21)

Air: 10
Other: 10
H&G: 10

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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

16. Nectarine and Peach

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Malathion ULV Concentrate
Insecticide (CA83001200), Prentox 51b Malathion Spray
(655-777), ProKil Malathion 25-WP (10163-61), and ProKil
Malathion 8E (10163-21)

Air: 9
Other: 9
H&G: 9

17. Cherry

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Drexel Malathion 5EC (19713-217), Malathion 5EC
(66330-220), Malathion 8EC (66330-248), Malathion
Insecticide (ULV) (66330-219), Malathion ULV (19713-
540), Malathion ULV Concentrate Insecticide (34704-18),
Malathion ULV Concentrate Insecticide (CA83001200),
Prentox 51b Malathion Spray (655-777), ProKil Malathion
25-WP (10163-61), ProKil Malathion 8E (10163-21), and
ProKil Malathion ULV (10163-44)

Air: 8
Other: 8
H&G: 8

18. Fig

Atrapa 5E (4787-44), Clean Crop Malathion 57EC (34704-
108), Clean Crop Malathion 8 EC Insecticide (34704-119),
Cythion 8 Aquamul (34704-474), Drexel Malathion 5EC
(19713-217), Malathion 5EC (66330-220), Malathion 8EC
(66330-248), Malathion ULV Concentrate Insecticide
(CA83001200), Prentox 51b Malathion Spray (655-777), and
ProKil Malathion 8E (10163-21)

Air: 2.5
Other: 2.5
H&G: 2.5

19. Apple, Pear, and Quince

Clean Crop Malathion 57EC (34704-108), Clean Crop
Malathion 8 EC Insecticide (34704-119), Malathion ULV
Concentrate Insecticide (CA83001200), and ProKil
Malathion 25-WP (10163-61)

Air: 1.25
Other: 1.5
H&G: 1.5

20. Guava, Mango, Plum, and
Prune

Clean Crop Malathion 57EC (34704-108), Clean Crop
Malathion 8 EC Insecticide (34704-119), Cythion 8 Aquamul
(34704-474), Malathion 5EC (66330-220), Malathion 8EC
(66330-248), Malathion ULV Concentrate Insecticide
(CA83001200), ProKil Malathion 25-WP (10163-61), and
ProKil Malathion 8E (10163-21)

Air: .75
Other: 1.5
H&G: 1.5

21. Papaya

Malathion ULV Concentrate Insecticide (CA83001200) and
Prentox 51b Malathion Spray (655-777)

Air: .175
Other: .175
H&G: 1.25

22. Garlic and Leek

Atrapa 5E (4787-44), Clean Crop Malathion 57EC (34704-
108), Clean Crop Malathion 8 EC Insecticide (34704-119),
Cythion 8 Aquamul (34704-474), Drexel Malathion 5EC
(19713-217), Malathion 5EC (66330-220), Malathion 8EC
(66330-248), Prentox 51b Malathion Spray (655-777),
Prentox Malathion 57% E.C. (655-794), and ProKil
Malathion 8E (10163-21)

Air: 2
Other: 2
H&G: 21.5

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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

23. Grapes

Atrapa 8E (4787-46), Clean Crop Malathion 57EC (34704-
108), Clean Crop Malathion 8 EC Insecticide (34704-119),
Clean Crop Malathion 8E Insecticide (34704-452), Cythion 8
Aquamul (34704-474), Drexel Malathion 5EC (19713-217),
Malathion 55 Insecticide Premimum Grade (34704-3),
Malathion 5EC (66330-220), Malathion 8EC (66330-248),
Malathion ULV Concentrate Insecticide (CA83001200),
Prentox 51b Malathion Spray (655-777), ProKil Malathion
25-WP (10163-61), and ProKil Malathion 8E (10163-21)

Air: 2.75
Other: 27.47
H&G: 2.75

26. Brussel Sprouts and .
Dandelion

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), ProKil
Malathion 25-WP (10163-61), and ProKil Malathion 8E
(10163-21)

Air: 2.5
Other: 2.5
H&G: 12.9

27. Swiss Chard, Chervil,
Endive (Escarole), Lettuce,
Head Lettuce, Leaf Lettuce
(Black Seeded Simpson, Salad
Bowl, Etc.), Orach (Mountain
Spinach), Parsley, Roquette
(Arrugula), Salsify, and
Spinach

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), ProKil
Malathion 25-WP (10163-61), and ProKil Malathion 8E
(10163-21)

Air: 2
Other: 2
H&G: 21.5

28. Peppermint

Cythion 8 Aquamul (34704-474), Drexel Malathion 5EC
(19713-217), Malathion 5EC (66330-220), Malathion 8EC
(66330-248), Prentox 51b Malathion Spray (655-777),
Prentox Malathion 57% E.C. (655-794), and ProKil
Malathion 8E (10163-21)

Air: 1
Other: 1
H&G: 10.75

29. Eggplant

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion ULV Concentrate Insecticide (CA83001200),
Prentox 51b Malathion Spray (655-777), and Prentox
Malathion 57% E.C. (655-794)

Air: 3.5
Other: 3.5
H&G: 21.5

30. Pumpkin

Clean Crop Malathion 57EC (34704-108), Clean Crop
Malathion 8 EC Insecticide (34704-119), Cythion 8 Aquamul
(34704-474), Drexel Malathion 5EC (19713-217), Malathion
ULV Concentrate Insecticide (CA83001200), Prentox 51b
Malathion Spray (655-777), Prentox Malathion 57% E.C.
(655-794), and ProKil Malathion 25-WP (10163-61)

Air: 2
Other: 2
H&G: 21.5

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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

31. Cucumber, Cucurbit
Vegetables, Melons -
Unspecified, Cantaloupe,
Honeydew, Musk, Water, and
Winter

(Casaba/Crenshaw/Honeydew/
Persian), and Squash (All Or
Unspecified)

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion ULV Concentrate Insecticide (CA83001200),
Prentox 51b Malathion Spray (655-777), Prentox Malathion
57% E.C. (655-794), ProKil Malathion 25-WP (10163-61),
and ProKil Malathion 8E (10163-21)

Air: 1.875
Other: 1.875
H&G: 21.5

32. Onion (Unspecified and
Green), Radish, and Shallot

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Prentox 51b Malathion
Spray (655-777), Prentox Malathion 57% E.C. (655-794),
ProKil Malathion 25-WP (10163-61), and ProKil Malathion
8E (10163-21)

Air: 2
Other: 2
H&G: 17.2

33. Potato - White/Irish

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Prentox 51b Malathion
Spray (655-777), Prentox Malathion 57% E.C. (655-794),
ProKil Malathion 25-WP (10163-61), and ProKil Malathion
8E (10163-21)

Air: 3
Other: 3
H&G: 17.2

34. Turnip

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), and
ProKil Malathion 25-WP (10163-61)

Air: 2.5
Other: 2.5
H&G: 12.9

35. Parsnip and Rutabaga

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Prentox 51b Malathion
Spray (655-777), Prentox Malathion 57% E.C. (655-794),
ProKil Malathion 25-WP (10163-61), and ProKil Malathion
8E (10163-21)

Air: 2
Other: 2
H&G: 12.9

36. Sweet Potato

Atrapa 5E (4787-44), Clean Crop Malathion 57EC (34704-
108), Cythion 8 Aquamul (34704-474), Drexel Malathion
5EC (19713-217), Malathion 5EC (66330-220), Malathion
8EC (66330-248), Prentox 51b Malathion Spray (655-777),
Prentox Malathion 57% E.C. (655-794), and ProKil
Malathion 8E (10163-21)

Air: 1.875
Other: 1.875
H&G: 21.5

48


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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

37. Bermudagrass, Bluegrass,
Canarygrass, Grass
Forage/Fodder/Hay, Pastures,
Peas (Including Vines),
Rangeland, Sudangrass, and
Timothy

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Drexel Malathion 5EC (19713-217), Malathion 5EC
(66330-220), Malathion 8EC (66330-248), Malathion
Insecticide (ULV) (66330-219), Malathion ULV (19713-
540), Malathion ULV Concentrate Insecticide (34704-18),
Prentox 51b Malathion Spray (655-777), ProKil Malathion
25-WP (10163-61), ProKil Malathion 8E (10163-21), and
ProKil Malathion ULV (10163-44)

Air: 1.25
Other: 1.25
H&G: 1.25

40. Beets, Cowpea/Blackeyed
Pea, and Peas (Unspecified
and Field)

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Cythion ULV Concentrate Insecticide (19713-288), Drexel
Malathion 50% Emulsifiable (19713-330), Drexel Malathion
5EC (19713-217), Malathion 55 Insecticide Premimum Grade
(34704-3), Malathion 5EC (66330-220), Malathion 8EC
(66330-248), Malathion ULV (19713-540), Prentox 51b
Malathion Spray (655-777), Prentox Malathion 57% E.C.
(655-794), ProKil Malathion 25-WP (10163-61), ProKil
Malathion 8E (10163-21), and ProKil Malathion ULV
(10163-44)

Air: 2.5
Other: 2.5
H&G: 25.8

41. Carrot (Including Tops),
Celtuce, Fennel, and Pepper

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Malathion ULV Concentrate
Insecticide (CA83001200), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), ProKil
Malathion 25-WP (10163-61), and ProKil Malathion 8E
(10163-21)

Air: 2
Other: 2
H&G: 17.2

42. Beans, Beans - Dried-
Type, Beans - Succulent
(Lima), and Beans - Succulent
(Snap)

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Drexel Malathion 5EC (19713-217), Malathion 55
Insecticide Premimum Grade (34704-3), Malathion 5EC
(66330-220), Malathion Insecticide (ULV) (66330-219),
Malathion ULV (19713-540), Malathion ULV Concentrate
Insecticide (34704-18), Malathion ULV Concentrate
Insecticide (CA83001200), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), ProKil
Malathion 25-WP (10163-61), and ProKil Malathion ULV
(10163-44)

Air: 1.75
Other: 1.75
H&G: 12.9

49


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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

43. Celery

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), ProKil
Malathion 25-WP (10163-61), and ProKil Malathion 8E
(10163-21)

Air: 1.5
Other: 1.5
H&G: 10.75

44. Asparagus and Safflower
(Unspecified)

Clean Crop Malathion 57EC (34704-108), Cythion 8
Aquamul (34704-474), Drexel Malathion 5EC (19713-217),
and ProKil Malathion 25-WP (10163-61)

Air: 1.25
Other: 1.25
H&G: 1.25

45. Anise

Drexel Malathion 5EC (19713-217), Prentox 51b Malathion
Spray (655-777), and Prentox Malathion 57% E.C. (655-794)

Air: .9375
Other: .9375
H&G: 10.75

46. Strawberry

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Malathion ULV Concentrate
Insecticide (CA83001200), Penco Malathion W-25 (655-
549), Prentox 51b Malathion Spray (655-777), Prentox
Malathion 57% E.C. (655-794), ProKil Malathion 25-WP
(10163-61), and ProKil Malathion 8E (10163-21)

Air: 2
Other: 2
H&G: 17.2

47. Sugar Beet

Clean Crop Malathion 57EC (34704-108) and
Clean Crop Malathion 8 EC Insecticide (34704-119)

Air: 1.875
Other: 1.875
H&G: 1.875

48. Tomato

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion ULV Concentrate Insecticide (CA83001200),
Prentox 51b Malathion Spray (655-777), Prentox Malathion
57% E.C. (655-794), and ProKil Malathion 25-WP (10163-
61)

Air: 3.5
Other: 3.5
H&G: 37.63

49. Okra

Atrapa 5E (4787-44), Clean Crop Malathion 57EC (34704-
108), Cythion 8 Aquamul (34704-474), Drexel Malathion
5EC (19713-217), Malathion 5EC (66330-220), Malathion
8EC (66330-248), Malathion ULV Concentrate Insecticide
(CA83001200), Prentox 51b Malathion Spray (655-777),
Prentox Malathion 57% E.C. (655-794), and ProKil
Malathion 8E (10163-21)

Air: 1.5
Other: 1.5
H&G: 12.9

50


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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

51. Sorghum

Atrapa 5E (4787-44), Clean Crop Malathion 57EC (34704-
108), Clean Crop Malathion ULV Concentrate Insecticide
(34704-565), Cythion 8 Aquamul (34704-474), CythionULV
Concentrate Insecticide (19713-288), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Malathion Insecticide
(ULV) (66330-219), Malathion ULV (19713-540), Malathion
ULV Concentrate Insecticide (34704-18), Prentox 51b
Malathion Spray (655-777), ProKil Malathion 8E (10163-21),
and ProKil Malathion ULV (10163-44)

Air: 1.5
Other: 1.5
H&G: 1.5

52. Barley, Cereal Grains,
Oats, Rye, and Wheat

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), CythionULV Concentrate Insecticide (19713-
288), Drexel Malathion 5EC (19713-217), Malathion 55
Insecticide Premimum Grade (34704-3), Malathion 5EC
(66330-220), Malathion 8EC (66330-248), Malathion
Insecticide (ULV) (66330-219), Malathion ULV (19713-
540), Malathion ULV Concentrate Insecticide (34704-18),
Prentox 51b Malathion Spray (655-777), ProKil Malathion
25-WP (10163-61), ProKil Malathion 8E (10163-21), and
ProKil Malathion ULV (10163-44)

Air: 1.25
Other: 1.25
H&G: N.A.

53. Gooseberry

Clean Crop Malathion 57EC (34704-108), Cythion 8
Aquamul (34704-474), Drexel Malathion 5EC (19713-217),
Malathion 5EC (66330-220), Malathion 8EC (66330-248),
Malathion ULV Concentrate Insecticide (CA83001200),
Prentox 51b Malathion Spray (655-777), and ProKil
Malathion 8E (10163-21)

Air: 16
Other: 16
H&G: 16

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and
Raspberry (Black - Red)

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Cythion 8 Aquamul (34704-474),
Drexel Malathion 5EC (19713-217), Malathion 55 Insecticide
Premimum Grade (34704-3), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Malathion ULV Concentrate
Insecticide (CA83001200), Penco Malathion W-25 (655-
549), Prentox 51b Malathion Spray (655-777), and ProKil
Malathion 8E (10163-21)

Air: 4
Other: 4
H&G: 7

55. Blueberry

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), CythionULV Concentrate Insecticide (19713-
288), Drexel Malathion 5EC (19713-217), Malathion 5EC
(66330-220), Malathion 8EC (66330-248), Malathion
Insecticide (ULV) (66330-219), Malathion ULV (19713-
540), Malathion ULV Concentrate Insecticide (34704-18),
Malathion ULV Concentrate Insecticide (CA83001200),
Prentox 51b Malathion Spray (655-777), ProKil Malathion 8E
(10163-21), and ProKil Malathion ULV (10163-44)

Air: 2.5
Other: 2.5
H&G: 2.5

51


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Scenario Group. Crop/Silc

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

56. Caneberries and Currant

Clean Crop Malathion 57EC (34704-108), Clean Crop
Malathion 8 EC Insecticide (34704-119), Cythion 8 Aquamul
(34704-474), Drexel Malathion 5EC (19713-217), Malathion
5EC (66330-220), Malathion 8EC (66330-248), Malathion
ULV Concentrate Insecticide (CA83001200), Prentox 51b
Malathion Spray (655-777), and ProKil Malathion 8E
(10163-21)

Air: 2
Other: 2
H&G: 2

57. Passion Fruit (Granadilla)

Cythion 8 Aquamul (34704-474), Malathion 5EC (66330-
220), Malathion 8EC (66330-248), Malathion ULV
Concentrate Insecticide (CA83001200), and ProKil
Malathion 8E (10163-21)

Air: .75
Other: .75
H&G: .7813

58. Mint and Spearmint

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Cythion 8 Aquamul (34704-
474), Drexel Malathion 5EC (19713-217), Malathion 5EC
(66330-220), Malathion 8EC (66330-248), Prentox 51b
Malathion Spray (655-777), Prentox Malathion 57% E.C.
(655-794), and ProKil Malathion 8E (10163-21)

Air: 1
Other: 1
H&G: 10.75

59. Rice and Wild Rice

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 57EC (34704-108), Clean Crop Malathion 8 EC
Insecticide (34704-119), Clean Crop Malathion 8E
Insecticide (34704-452), Clean Crop Malathion ULV
Concentrate Insecticide (34704-565), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Drexel Malathion 5EC (19713-217), Malathion 5EC
(66330-220), Malathion 8EC (66330-248), Malathion
Insecticide (ULV) (66330-219), Malathion ULV (19713-
540), Malathion ULV Concentrate Insecticide (34704-18),
Prentox 51b Malathion Spray (655-777), ProKil Malathion 8E
(10163-21), and ProKil Malathion ULV (10163-44)

Air: 1.5625
Other:
1.5625
H&G: 2

61. Water Cress

Atrapa 5E (4787-44), Clean Crop Malathion 8 EC Insecticide
(34704-119), Cythion 8 Aquamul (34704-474), Drexel
Malathion 5EC (19713-217), Malathion 5EC (66330-220),
Malathion 8EC (66330-248), Prentox 51b Malathion Spray
(655-777), Prentox Malathion 57% E.C. (655-794), and
ProKil Malathion 8E (10163-21)

Air: 2
Other: 2
H&G: 12.9

Non-agricultural Uses

Forestry. Christmas Tree
Plantations, Pine (Seed
Orchard), and Slash Pine
(Forest)

Atrapa 5E (4787-44), Cythion 8 Aquamul (34704-474),
Malathion 8EC (66330-248), Prentox 51b Malathion Spray
(655-777), and ProKil Malathion 8E (10163-21)

Air: 3.2
Other: 3.2
H&G: N.A.

Mosquito Control.

Intermittently Flooded
Areas/Water,

Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs
(without Human or Wildlife
Use), Polluted Water, and
Swamps/MarshesAV etlands/St
agnant Water

Atrapa 5E (4787-44), Atrapa 8E (4787-46), Clean Crop
Malathion 8 EC Insecticide (34704-119), Clean Crop
Malathion 8E Insecticide (34704-452), Cythion 8 Aquamul
(34704-474), Cythion ULV Concentrate Insecticide (19713-
288), Malathion 55 Insecticide Premimum Grade (34704-3),
Malathion 5EC (66330-220), Malathion 8EC (66330-248),
Prentox 51b Malathion Spray (655-777), and ProKil
Malathion 8E (10163-21)

Air: .6
Other: .6
H&G: .6

Nursery. Outdoor Nursery

N.A.

Air: 2.25b
Other: 2.25b

52


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Scenario Group. Crop/Site

Labels with Crop/Site (Registration Numbers)

Maximum
Lbs. ai/A

Public Health and Medfly
Control. Nonagricultural
Areas (Public Health Use),
Urban Areas, and Wide
Area/General Outdoor
Treatment (Public Health Use)

Clean Crop Malathion ULV Concentrate Insecticide (34704-
565), CythionULV Concentrate Insecticide (19713-288),
Malathion Insecticide (ULV) (66330-219), Malathion ULV
(19713-540), and ProKil Malathion ULV (10163-44)

Air: .6119
Other: .1361
H&G: N.A.

Residential.

Household/Domestic
Dwellings Outdoor Premises,
Ornamental and/or Shade
Trees, Ornamental Herbaceous
Plants, Ornamental Lawns and
Turf, Ornamental Non-
flowering Plants, Ornamental
Woody Shrubs and Vines, and
Urban Areas

Atrapa 5E (4787-44), Clean Crop Malathion 57EC (34704-
108), Clean Crop Malathion ULV Concentrate Insecticide
(34704-565), CythionULV Concentrate Insecticide (19713-
288), Malathion 55 Insecticide Premimum Grade (34704-3),
Malathion 8EC (66330-248), Malathion Insecticide (ULV)
(66330-219), Malathion ULV (19713-540), Malathion ULV
Concentrate Insecticide (CA83001200), ProKil Malathion 25-
WP (10163-61), and ProKil Malathion ULV (10163-44)

Other: .25°

Rights-of-way.

Nonagricultural Rights-of-
way/Fencerows/Hedgerows
and Nonagricultural
Uncultivated Areas/Soils

Atrapa 8E (4787-46), Clean Crop Malathion 57EC (34704-
108), Clean Crop Malathion 8 EC Insecticide (34704-119),
Clean Crop Malathion 8E Insecticide (34704-452), Clean
Crop Malathion ULV Concentrate Insecticide (34704-565),
CythionULV Concentrate Insecticide (19713-288),
Malathion Insecticide (ULV) (66330-219), Malathion ULV
(19713-540), Malathion ULV Concentrate Insecticide
(34704-18), and Prentox 51b Malathion Spray (655-777)

Air: .9281
Other: .9281
H&G: 2.5

Turf. Golf Course Turf

Atrapa 8E (4787-46) and Malathion 8EC (66330-248)

Air: 1.25
Other: 1.25

a Because of the large number of malathion labels, only a select subset of labels (see text) was evaluated.
Additional current labels may include these crop/sites, but should not exceed the maximum application
rates indicated in this table.

b Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from
2.23 lbs./A).

0 Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does
not assume the same parcels are re-treated each weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25
lbs. ai/A.

No label rates appear to specifically address outdoor nursery uses, while the CDPR PUR
data indicates that such uses exist. (In this case, it is assumed that such uses are permitted
under numerous label uses.) An outdoor nursery scenario group was created to address
this use. To estimate a suitable application rate, the average application rate of 2.23 lbs/A
as indicated in the 2001-2005 CDPR PUR data was rounded upward to 2.25 lbs. ai/A for
this scenario group (Table 6).

A residential scenario was constructed based on the maximum home and garden
application rates. The citrus home and garden application rate of 25 lbs. ai/A was used. It
is assumed that only one hundredth of the standard 10 acre residential watershed (0.1
acre) would be treated at such a rate on any given week, but that similar applications
might occur every week over ten consecutive weeks. (Each week's application(s) may be
to the same or different portions of the watershed.). The application rate is adjusted to
reflect that only one hundredth of the watershed has malathion applied to it by dividing

53


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the application rate by 100 to get an effective application rate of 0.25 lbs. ai/A applied
over the entire watershed (Table 6).

3.1.2 Application Timing

Two different sources of information were used to determine the timing of malathion
applications for each scenario group. The maximum number of applications per growing
season and minimum days before re-treatment with malathion were obtained from the
Label Use Information System (LUIS) report produced by OPP, BEAD. Because the
majority of the current labels do not provide this information, the maximum number of
applications and minimum days before re-treatment provided on any of the labels listed
for each exposure scenario group in Table 6 were used (missing values excluded). Where
no label relevant to the exposure scenario group provides this information, the
applications per growing season and re-treatment interval were estimated from the most
similar scenario groups (Table 8).

Application dates for each crop/site were derived from the CDPR PUR data set. For each
exposure scenario group, trends in malathion application (lbs/day) were obtained using
moving averages (Figure 9). Inter-year variation in malathion application are depicted
using a 60-day moving average for CDPR PUR data from 2001-2005 in the left graphs of
Figure 9. This graph provides some indication of whether intra-annual temporal trends in
malathion applications are consistent between years. The right-hand graphs show a 16-
day moving average calculated across all 5 years of CDPR PUR data. (This can be
thought of as the average moving-average for these years.) The peak of the right graph is
used to calculate the midpoint of the malathion application period used in each PRZM
scenario. Using this peak value and the applications per growing season and re-treatment
intervals from Table 8, the first and last scenario application days (dashed lines in
Figure 9) are calculated to bracket the peak of the malathion application for each
exposure scenario group.

54


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year application timing (right graph) by crop use according to the CDPR PUR data. Malathion
application period (first to last applications), according to each scenario, is indicated by dashed black
vertical lines (right graph only).

55


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6. Date

200 i	

180 -
160 -
140 -
120 -
100 -
80 -
60 -
40 -
20 -

0 4-i—r

1/1/2001

200

< 100

50

1/1/2002 1/1/2003 1/1/2004
Date

1/1/2005 1/1/2006

M J J A S
Calendar Date

7. Filbert (Hazelnut)- No data in CaPUR

8. Avocado

45 ~t
40 -
35 -
30 -
25 -
20 -
15 -
10 -
5 -
0 -

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date





M4-

,rS,

M J J A S
Calendar Date

9. Citrus, Citrus Hybrids other than Tangelo, Grapefruit, Kumquat, Lemon, Lime, Orange, Tangelo, and

Tangerines

300 ¦

250 -

O 200 -

100 ¦

50 ¦



1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

A M J J A S
Calendar Date

O N

Figure 9. Continued.

56


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100 ¦

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

10. Amaranth - Chinese, Broccoli (Unspecified, Chinese, and Raab), Cabbage (Unspecified and Chinese),
CanolaYRape, Cauliflower, Collards, Corn Salad, Dock (Sorrel), Horseradish, Kale, Kohlrabi, Mustard,
Mustard Cabbage (Gai Choy/Pak-Choi), and Purslane (Garden and Winter)

11. Corn (Unspecified, Field, Pop, and Sweet) and Millet (Foxtail)

12. Cotton

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M A M J J A S
Calendar Date

A M J J A S
Calendar Date

100

M J J A S
Calendar Date

Figure 9. Continued.

57


-------
15. Apricot

0.16
0.14 -
0.12 -
0.1
0.08
0.06 -
0.04
0.02
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

0.14

\ 012

-S

I 01

| 0.08
a.

% 0.06
| 0.04
| 0.02
0

J F J MAM J J AS
Calendar Date

O N D

16. Nectarine and Peach

2.5

a 1.5
a

<

0.5

ha

5" 2.5

a 1.5
a

<

g 1



V

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

J F J

M J J A S
Calendar Date

O N D

17. Cherry

35

'§• 30
-s

I 25

1 20

"a
c

.2 10

h



1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

18
16
14
12
10

4

2 -
0

D

n

J F J MA

M J J A S
Calendar Date

O N D

Figure 9. Continued.

58


-------
18. Fig

40
35 -
30 -
25
20
15 -
10

Jl

JX

JL

'«	30

-3

I	25

1	20

a.

£	15

Ac

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

J F J MAM J J AS
Calendar Date

O N D

19. Apple, Pear, and Quince

4.5 -|	

! 4 -
3.5 -
¦ 3 -
2.5 -

: 2 -

"¦J

1/1/2001



-FX

"a 3 -
a

<

a 9 .

.2

2

I i-

X



1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M A M J J A S
Calendar Date

O N D

20. Guava, Mango, Plum, and Prune

0.7 -

'§• 0.6 -
-s

I 0.5 -

1 °-4 ¦

I 0-3 -

.2 0.2 -

JS

I 0.1 -





1/1/2001 1/1/2002

1/1/2003 1/1/2004
Date

1/1/2005 1/1/2006

0.5
0.45
0.4
0.35
0.3
0.25
0.2 -
0.15
0.1
0.05
0

Jl

r~i n

M A

M J J A S
Calendar Date

O N D

Figure 9. Continued.

59


-------
21. Papaya - No data in CaPUR

160 i	

140 -
120 -
100 -
80 -
60 -
40 -
20 -
0 l-i-i

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

22. Garlic and Leek

		70





M J J A S
Calendar Date

23. Grapes

160

\ 140 H
¦a

*	120

®	100

u

a 80
a.

B 60 H
©

2 40

j











7



A\

/A

iA

A

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M A M J J A S
Calendar Date

O N D

0.35

'§• 0.3
-s

I 0.25

1 °-2

I 0.15
s

.2 0.1
¦c

1 0.05

5!

o

26. Brussel Sprouts and Dandelion

		0.4

¦Q 0.35
1 0.3

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M J J A S
Calendar Date

Figure 9. Continued.

60


-------
27. Swiss Chard, Chervil, Endive (Escarole), Lettuce, Head Lettuce, Leaf Lettuce (Black Seeded Simpson,
Salad Bowl, Etc.), Orach (Mountain Spinach), Parsley, Roquette (Arrugula), Salsify, and Spinach

1/1/2001 1/1/2002 1/1/2003 1/1/2004
Date

1/1/2005 1/1/2006

J F J

M J J A S
Calendar Date

28. Peppermint

1.2 -
1 -

0.8 -
0.6 -
0.4 -
0.2 -

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

1/1/2006

1 j-

0.9 -
4 0.8 -

I °-7~

¦s 0.6 -

a>

% 0.5 -
a

•< 0.4 -
.2 0.3 -

JS

1 0.2 -

I 0.1 -

0 —

I I
I I
I I



J F J MA

M J J A S
Calendar Date

O N D

29. Eggplant

1.8 -

V, 1.6 -
s

Z 14 ¦

§ 1.2 -

1 1 "

ft 0.8 -
<

§ 06 "

5 0.4 -

C3

I a2

o -

AI ^

is

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

1/1/2006

1 j-

-C	0.9 -

4	0.8 -

I	°-7~

T3	0.6 -
v

%	0.5 -
a

•<	0.4 -

.2	0.3 -

JS

1	0.2 -

cs

5	0.1-

o —

jvj



[L

J F J MA

M J J A S
Calendar Date

O N D

Figure 9. Continued.

61


-------
50
*£ 45

C5

T5 40

I35

¦g 30

1. 25

a

< 20

I 15

1 10

5! 5
o













:A

A

A

n





30. Pumpkin

30
25

-a

§ 20 -

73

K

U 15
a

§ 10

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

0

F J

i
i

i |

i
i
i

if

i
i
i
i
i





M J J A S
Calendar Date

O N D

31. Cucumber, Cucurbit Vegetables, Melons - Unspecified, Cantaloupe, Honeydew, Musk, Water, and
Winter (Casaba/Crenshaw/Honeydew/Persian), and Squash (All Or Unspecified)

15

< 10

1/1/2002 1/1/2003 1/1/2004
Date

1/1/2005 1/1/2006

M J J A S
Calendar Date

O N D

32. Onion (Unspecified and Green), Radish, and Shallot

120

40







i

L



A

A,

M

l\l

\

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M J J A S
Calendar Date

Figure 9. Continued.

62


-------
14

12 -
10 -
8
6

4 -
2 -
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

fk

33. Potato - White/Irish

		16 -

"C	14 -

S3

1	12-

X!

3	io -

J

1
1
1
1
1
1

1
1
1
1
1
1
1
1
1
1
1
1

1
1

nA „

: F J MA

M J J A S
Calendar Date

O N D J

4.5 ~t
! 4 -
3.5 -
- 3 -
2.5 -
: 2-
1.5 -
1 -
0.5 -
0 -

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

iV

34. Turnip

3.5
V 3 -\

C3

-a

| 2.5

1 2

"a.

t 1-5

s

I 1

«5

3 0.5

l~l—-

[L

1/1/2006

M J J A S
Calendar Date

35. Parsnip and Rutabaga

1.2

1 -
0.8
, 0.6
0.4 -
0.2

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

1/1/2006

1 j-

^	0.9 -

-§	0.8 -

|	0.7 -

T5	0.6 -

S,	0.5 -
a

<	0.4 -
&

|	0.3 -

S	0.2 -

s

S	0.1 -
o —

:F J M A

M J J A S
Calendar Date

O N D J

Figure 9. Continued.

63


-------
36. Sweet Potato

5

! 4.5
4
3.5
3 -
. 2.5 -
2 -
1.5 -
1 -
0.5
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004
Date

TL

1/1/2005 1/1/2006

5 j-
^ 4.5 -
-§ 4 -

I 35 ~

¦s 3 -

v

1. 2.5 -
a

< 2 -
&

I 1-5"

« 1 -

S3

S 0.5-
0 —

:F J MAM

J J A
Calendar Date

37. Bermudagrass, Bluegrass, Canary grass, Grass Forage/Fodder/Hay, Pastures, Peas (Including Vines),

Rangeland, Sudangrass, and Timothy

' 70
60
50 -
, 40 -
30 -
20
10
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

k



45 -

•P	40 -
s

¦o	35 -

§	30 -

T3

a	25 "

"a

a	2o -

I	15 ¦

|	10 -
"es

S	5 -
0 -

f



JZL

. F J MAM J J A
Calendar Date

O N D J

40. Beets, Cowpea/Blackeyed Pea, and Peas (Unspecified and Field)

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006

Calendar Date

Figure 9. Continued.

64


-------
41. Carrot (Including Tops), Celtuce, Fennel, and Pepper

50 -

20



1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

40 -r
35 -
30 -
25 -
20 -
15 -
10 -
5 -
0 -



j

M A M J J A S
Calendar Date

O N

42. Beans, Beans - Dried-Type, Beans - Succulent (Lima), and Beans - Succulent (Snap)

160
\ 140



A









:A

i







A

40
20
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

100 j-
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0 —

J

M J J A S
Calendar Date

43. Celery

1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M J J A S
Calendar Date

Figure 9. Continued.

65


-------
44. Asparagus and Safflower (Unspecified)

-fl.

7

6
5

4 -
3 -
2 -
1
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M A

M J J A S
Calendar Date

45. Anise - No data in CaPUR

46. Strawberry

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

M J J A S
Calendar Date

47. Sugar Beet

0.045 i	

, 0.04 -
0.035 -
0.03 -
0.025 -
! 0.02 -
0.015 -
0.01 -
0.005 -

0 4-i-

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

0.02

-3 0.015

F J M A

M J J A S
Calendar Date

Figure 9. Continued.

66


-------
160
140
120
100

20 ¦
0 -













:A

-A-

\

A





48. Tomato

90

a. 40
<







V.

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

. F J MA

M J J A S
Calendar Date

O N D

49. Okra

3.5
1 3
2.5 -
2

' 1.5

1 -
0.5 -
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

1/1/2006

3 j-
2.5 -

-s

-o 9 _

0	l
-o

V

?¦ 1.5 -
a
<

1	1 "

-5

¦3 0.5 -

S

0 —

:F J M A

M J J A S
Calendar Date

O N D J

4.5
. 4 H
3.5

- 3
2.5 -

: 2

1.5 -
1 -
0.5
0

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

51. Sorghum

4.5 ¦

n

4 -
3.5 -
3 -
2.5 -
2 -
1.5 -
1 -
0.5 -
0 —

:F J MAM

J J A S
Calendar Date

O N D J

Figure 9. Continued.

67


-------
52. Barley, Cereal Grains, Oats, Rye, and Wheat

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

100
90 -
80 -
70 -
60
50
40 -
30 -
20
10
0

1

1

1 1



y





I

.FJMAMJ JAS
Calendar Date

O N D J

53. Gooseberry - No data in CaPUR

54. Blackberry, Boysenberry, Dewberry, Loganberry, and Raspberry (Black - Red)

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

1/1/2006

M J J A S
Calendar Date

55. Blueberry

12
10 -
8
6

4 -
2

J

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

T5 7 -

I 6-

1	5 ~

"a

< 4"

e o _
.2

2

tz 2 ~

R

S 1 -

o —

IK

; F J MA

M J J A S
Calendar Date

O N D J

56. Caneberries and Currant - No data in CaPUR

57. Passion Fruit (Granadilla)- \'o data in CaPUR

Figure 9. Continued.

68


-------
58. Mint and Spearmint

1/1/2002 1/1/2003 1/1/2004
Date

1/1/2005 1/1/2006

J J A
Calendar Date

45 T

, 40 -
35 -
30 -
25 -

: 20 -

15 -
10 -
5 -

o -

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

59. Rice and Wild Rice

		60 -I	

'?? 50 -

T3

I 40 -
•a

i. 30 -
a
<

1	20 "

2

«

« 10 -

1/1/2006

: F J MA

M J J A S
Calendar Date

O N D J

61. Water Cress

4.5
V 4 H

3.5
I 3

1 2-5 "

"a,

t 2

§ 1-5 i
5 l -

C3

I 05

0

/M



1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005
Date

1/1/2006

M J J A
Calendar Date

Figure 9. Continued.

69


-------
70


-------
1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

Residential: Landscape Maintenance

0.045 -|	

¦P 0.04 -

¦§ 0.035 -

£ 0.03 -

I 0.025 -

% 0.02 -
<

J 0.015 -
| 0.01
| 0.005
0

M J J A S
Calendar Date

Rights-of-way. Nonagricultural Rights-of-way/Fencerows/Hedgerows and Nonagricultural Uncultivated

Areas/Soils

3.5

S3 J ~

-a

I 2-5

"a.

$1.5
s

.2 1 H
-c

I 0.5 -

0

1/1/2001





1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

a 1.5
a
<

i i

N

:F J M A

M J J A S
Calendar Date

O N D J



90

,4"—v



'>*

SO

a



-o

70

£

60

-s





50





Q.

40

<

a

30



£j

9.0

a



S3

s

10

Ui

Turf. Golf Course Turf



Ur

1/1/2001 1/1/2002 1/1/2003 1/1/2004 1/1/2005 1/1/2006
Date

180
•P 160 H

ss

140 -

§ 120

1 100
"a

<

J 60"

J2 40

"r

S 20 -

0





.F J M A

M J J A S
Calendar Date

O N D J

Figure 9. Continued.

3.2 Aquatic Exposure Assessment

The aquatic exposure assessment estimates the environmental concentrations of
malathion and maloxon to which aquatic organisms are expected to be exposed. The
estimated exposure concentrations will be used in subsequent sections to estimate the
effects of malathion exposure on CRLF (direct effects) and on the CRLF habitat and prey
(indirect effects). The linked models of PRZM (USEPA 1997a) and EXAMS (USEPA
1997b) are used to estimate aquatic malathion and maloxon concentrations.

71


-------
Additionally, measured surface water, air, and spray drift monitoring data are presented
and compared to the PRZM/EXAMS estimates. Because the risk assessment is intended
to be protective of the CRLF, the PRZM/EXAMS estimates are based on conservative
(protective) assumptions and, therefore, should be higher than measured concentrations,
but not so high as to be unrealistic.

3.2.1 A quatic Exposure Modeling

Typically, the Agency conducts modeling using scenarios intended to represent use sites
in areas that are highly vulnerable to either runoff, erosion, or spray drift. Runoff
estimates predicted by the PRZM model are linked to the Exposure Analysis Modeling
System (EXAMS). For ecological risk assessment, the Agency relies on a standard water
body to receive the edge-of-field runoff estimates. The standard water body is of fixed
geometry and includes the processes of degradation and sorption expected to occur in
ponds, canals, and low order streams (e.g., first and second order streams). The water
body is static (no outflow). The CLRF inhabits a range of water bodies, but generally
prefers perennial or near perennial waters in order to complete its lifecycle. Generally it
inhabits watersheds and drainages of 4th order or lower streams.

3.2.1.1 PRZM/EXAMS Inputs

Chemical specific input parameters for PRZM and EXAMS are summarized in Table 7,
respectively. Certain assumptions were made for chemical dissipation parameters
included in PRZM 3.1:

1.	The aerobic soil-metabolism half-life of 3 days (see following discussion) was
used for the adsorbed and dissolved half-life throughout the soil column. Subsoil
layers were assumed not to be anaerobic, as the deepest soil column simulated
was only 150 cm deep.

2.	A foliar decay rate of 0.126 d"1 was used based on the 90% upper confidence limit
of 37 foliar half-lives reported in Willis and McDowell (1987).

3.	Volatilization from the soil or foliage was not simulated (set to zero). Registrant
submitted data suggest that volatilization is not an important route of dissipation.

4.	Dissipation through plant uptake was not simulated.

5.	Foliar wash-off of 0.5 cm"1 was simulated, although data exist showing complete
wash-off of organophosphate pesticides with the first 0.1 cm of rainfall.

6.	An application efficiency of 95% was assumed for all application methods. Drift
from aerial applications was assumed to be 5% of the applied mass of malathion,
and that from non-aerial applications was assumed to be 1% of the applied mass.

The aerobic soil half-life for malathion chosen for modeling purposes was 3 days. This
value is consistent with that used for USDA modeling in for malathion in the boll weevil
eradication program. Degradation rates in soils vary greatly from the registrant supported

72


-------
half-life of 0.2 days to 11 days in rangeland soil with low organic content.12 Open
literature values are mostly greater than those observed in the acceptable submitted
aerobic soil metabolism study. However, because the conditions and parameters
controlled in the different open literature studies vary greatly it is not possible to calculate
an upper 90th percentile limit of the values. In this instance, multiplying the registrant's
submitted half-life value of 0.2 days by three to estimate the 90th percentile upper
confidence limit did not produce a conservative value relative to published literature
(Table 4). Using a single half-life value for modeling multiple scenarios is clearly a
simplification in this instance but it is necessary to choose a value that is a conservative
estimate of malathion degradation in agricultural settings used in modeling. The 3 day
half-life chosen is not the highest available value published but conditions favoring very
long persistence {i.e., very low moisture levels and microbial counts) are not expected to
commonly occur in agricultural settings.

PRZM and EXAMS require that degradation half lives be converted into rate constants.
The aerobic soil metabolism half-life of 3 days (as explained above) was converted to a
daily rate constant for PRZM 3.1 by the equation Ln(2)/(Ti/2). The aerobic aquatic (input
variable KBACW), anaerobic aquatic (KABCS), and photolysis (KDP) half-lives for
EXAMS were converted to hourly rate constants using the formula Ln(2)/(Ti/2 x 24).
Hydrolysis half-lives at pH 7(KNH) and pH9 (KBH) were converted to rate constants by
solving two simultaneous equations with the stable pH5 (KAH) constant set to zero.

12

Buckman, H.O. and Brady, N.C., 1969. The Nature and Properties of Soils. Macmillian Company,
Collier-Macmillian Limited, London as referrenced in USD A/APHIS National Boll Weevil Cooperative
Control Program. Final Environmental Impact Statement Volume 1, 1991.

73


-------
Table 7. PRZM/EXAMS input parameters for malathion and maloxon.

Input Parameter

Malathion

Maloxon

PRZM Parameters

Foliar Volatilization (PLVKRT)

Od1

Od1

Foliar Decay Rate (PLDKRT)

0.126 d"1

0.126 d"1

Foliar Wash-off Extraction Coefficient (FEXTRC)

0.5 cm"1

0.5 cm"1

Plant Uptake Fraction (UPTKF)

0

0

Partition Coefficient (Koc) for all crops

151Lkg1

46 L kg"1

Dissolved Phase Decay Rate: All Horizons (DWRATE)

0.231 d"1

0.1304 d"1

Adsorbed Phase Decay Rate: All Horizons (DSRATE)

0.231 d"1

0.1304 d"1

Vapor Phase Decay Rate (DGRATE) (all horizons)

Od1

Od"1

EXAMS Parameters

Aerobic Aqueous Metabolism Constant (KBACW)

8.82 x 10"3 h"1

8.82 x 10"3 h"1

Sediment Metabolism Constant (KBACS)

3.78 x 10"3 h"1

3.78 x 10"3 h"1

Acid Hydrolysis Rate Constant (KAH)

Oh"1

Oh"1

Neutral Hydrolysis Rate Constant (KNH)

4.10 x 10"3 h"1

4.10 x 10"3 h"1

Alkaline Hydrolysis Rate Constant (KBH)

5.46 x 103h_1

5.46 x 103h_1

Photolysis Rate Constant (KDP)

2.95 x 10"4h_1

2.95 x 10"4h_1

Partition Coefficient (KOC) for all modeled crops

151

46

Molecular Mass (MWT)

330 g -mol"1

314.29 g-mol"1

Solubility (SOL)

145 ppm

145 ppm

Henry's Law Constant (HENRY)

0

0

Q10 For The water Column (QTBAW)

2

2

Q10 For Sediment (QTBAS)

2

2

3.2.1.2 PRZM Scenarios

Although the labels for malathion typically do not restrict malathion applications
geographically within the CRLFs range, different malathion uses can be expected to
occur in different regions of California. To incorporate the effects of local variation in
soil properties, meteorology, etc., the scenarios evaluated are based on specific PRZM
scenarios and meteorological station data appropriate to each crop/site. Table 8
summarizes the application rates and timing and PRZM scenario name and location.

74


-------
Table 8. Characteristics (application rates, number of applications and timing, PRZM scenario name and meteorological station) of the PRZM/EXAMS

Scenario Group. Label Crop/Silc

Maximum
Application

Rates1
(Lbs. ai/A)

Applications per Crop
Cycle
(Minimum Days
before Re-treatment)

2001 - 2005 Peak
Application Date
(First and Last
Application Dates)

PRZM Scenario
Name

PRZM Scenario
Meteorological
Station

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine, Trefoil, and
Vetch

Air: 2
Other: 2

2(7)

3/15 (3/11-3/18)

CA alfalfa OP

Fresno, CA (W93193)

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

7(7)

8/25 (8/4 - 9/17)

CA almond STD

Sacramento, CA
(W23232)

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

3(6)

8/25 (8/19-8/31)

CA almond STD

Sacramento, CA
(W23232)

4. Chestnut

Air: 5
Other: 5

4(7)

8/25 (8/15 - 9/4)

CA almond STD

Sacramento, CA
(W23232)

5. Almond

Air: 1.25
Other: 4

3(6)

3/21 (3/15-3/27)

CA almond STD

Sacramento, CA
(W23232)

6. Date

Air: 1
Other: 2

3(14)

8/28 (8/14-9/11)

CA almond STD

Sacramento, CA
(W23232)

7. Filbert (Hazelnut)

Air: .625
Other: .625

3(6)

8/25 (8/19-8/31)

CA almond STD

Sacramento, CA
(W23232)

8. Avocado

Air: 9
Other: 9

2(6)

7/14 (7/11-7/17)

CA avocado RLF

San Diego County
(W23188)

9. Citrus, Citrus Hybrids other than Tangelo,
Grapefruit, Kumquat, Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

3(6)

3/23 (3/17 - 3/29)

CA citrus STD

Bakersfield, CA
(W23155)

10. Amaranth - Chinese, Broccoli (Unspecified,
Chinese, and Raab), Cabbage (Unspecified and
Chinese), CanolaVRape, Cauliflower, Collards, Corn
Salad, Dock (Sorrel), Horseradish, Kale, Kohlrabi,
Mustard, Mustard Cabbage (Gai Choy/Pak-Choi),
and Purslane (Garden and Winter)

Air: 2.5
Other: 2.5

6(7)

7/17 (6/29 - 8/3)

CA cole crop RLF

Santa Maria (W23234)

11. Corn (Unspecified, Field, Pop, and Sweet) and
Millet (Foxtail)

Air: 1.5
Other: 1.5

3(2)

8/14 (8/12 - 8/16)

CA corn OP

Sacramento, CA
(W23232)

12. Cotton

Air: 4
Other: 4

25 (3)

6/27 (5/22 - 8/2)

CA cotton STD

Bakersfield, CA
(W23155)

75


-------
Scenario Group. Label Crop/Silc

Maximum
Application

Rates1
(Lbs. ai/A)

Applications per Crop
Cycle
(Minimum Days
before Re-treatment)

2001 - 2005 Peak
Application Date
(First and Last
Application Dates)

PRZM Scenario
Name

PRZIM Scenario
Meteorological
Station

15. Apricot

Air: 10
Other: 10

4(6)

6/5 (5/27 - 6/14)

CA fruit STD

Fresno, CA(W93193)

16. Nectarine and Peach

Air: 9
Other: 9

4(6)

8/10 (8/1 - 8/19)

CA fruit STD

Fresno, CA (W93193)

17. Cherry

Air: 8
Other: 8

6(6)

5/31 (5/16-6/15)

CA fruit STD

Fresno, CA(W93193)

18. Fig

Air: 2.5
Other: 2.5

3(5)

7/23 (7/18 - 7/28)

CA fruit STD

Fresno, CA(W93193)

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

10(6)

7/27 (6/30 - 8/23)

CA fruit STD

Fresno, CA(W93193)

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

12(6)

5/25 (4/22 - 6/27)

CA fruit STD

Fresno, CA(W93193)

21. Papaya

Air: .175
Other: .175

12(6)

5/25 (4/22 - 6/27)

CA fruit STD

Fresno, CA(W93193)

22. Garlic and Leek

Air: 2
Other: 2

5(7)

5/14 (4/30 - 5/28)

CA garlic RLF

Fresno, CA (W93193)

23. Grapes

Air: 2.75
Other: 27.47

2(6)

6/5 (6/2 - 6/8)

CA grapes STD

Fresno, CA(W93193)

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

3(7)

5/27 (5/20 - 6/3)

CA lettuce STD

Santa Maria, CA
(W23273)

27. Swiss Chard, Chervil, Endive (Escarole),
Lettuce, Head Lettuce, Leaf Lettuce (Black Seeded
Simpson, Salad Bowl, Etc.), Orach (Mountain
Spinach), Parsley, Roquette (Arrugula), Salsify, and
Spinach

Air: 2
Other: 2

6(5)

9/11 (8/29 -9/23)

CA lettuce STD

Santa Maria, CA
(W23273)

28. Peppermint

Air: 1
Other: 1

3(7)

5/23 (5/16 - 5/30)

CA lettuce STD

Santa Maria, CA
(W23273)

29. Eggplant

Air: 3.5
Other: 3.5

5(5)

8/14 (8/4 - 8/24)

CA tomato STD

Fresno, California
(W93193).

30. Pumpkin

Air: 2
Other: 2

6(6)

8/27 (8/12-9/11)

CA melons RLF

Fresno County, (W
93193)

76


-------
Scenario Group. Label Crop/Silc

Maximum
Application

Rates1
(Lbs. ai/A)

Applications per Crop
Cycle
(Minimum Days
before Re-treatment)

2001 - 2005 Peak
Application Date
(First and Last
Application Dates)

PRZM Scenario
Name

PRZIM Scenario
Meteorological
Station

31. Cucumber, Cucurbit Vegetables, Melons -
Unspecified, Cantaloupe, Honeydew, Musk, Water,
and Winter (Casaba/Crenshaw/Honeydew/Persian),
and Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

6(6)

8/29 (8/14 - 9/13)

CA melons RLF

Fresno County, (W
93193)

32. Onion (Unspecified and Green), Radish, and
Shallot

Air: 2
Other: 2

5(7)

4/3 (3/20 - 4/17)

CA onion STD

Bakersfield, CA
(W23155)

33. Potato - White/Irish

Air: 3
Other: 3

5(7)

6/6 (5/23 - 6/20)

CA potato RLF

Bakersfield, CA
(W23155)

34. Turnip

Air: 2.5
Other: 2.5

5(7)

5/7 (4/23 - 5/21)

CA potato RLF

Bakersfield, CA
(W23155)

35. Parsnip and Rutabaga

Air: 2
Other: 2

5(7)

7/24 (7/10 - 8/7)

CA potato RLF

Bakersfield, CA
(W23155)

36. Sweet Potato

Air: 1.875
Other: 1.875

2(7)

9/20 (9/16 - 9/23)

CA potato RLF

Bakersfield, CA
(W23155)

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas (Including
Vines), Rangeland, Sudangrass, and Timothy

Air: 1.25
Other: 1.25

3(1)

5/17 (5/16 - 5/18)

CA rangeland hay
RLF

Sacramento, CA
(W23232)

40. Beets, Cowpea/Blackeyed Pea, and Peas
(Unspecified and Field)

Air: 2.5
Other: 2.5

5(7)

7/8 (6/24 - 7/22)

CA row crop RLF

Monterey County,
California (Santa
Maria) (W23234)

41. Carrot (Including Tops), Celtuce, Fennel, and
Pepper

Air: 2
Other: 2

7(5)

9/1 (8/17 - 9/16)

CA row crop RLF

Monterey County,
California (Santa
Maria) (W23234)

42. Beans, Beans - Dried-Type, Beans - Succulent
(Lima), and Beans - Succulent (Snap)

Air: 1.75
Other: 1.75

3(6)

8/18 (8/12 - 8/24)

CA row crop RLF

Monterey County,
California (Santa
Maria) (W23234)

43. Celery

Air: 1.5
Other: 1.5

2(7)

10/11 (10/7 - 10/14)

CA row crop RLF

Monterey County,
California (Santa
Maria) (W23234)

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

9(7)

3/9 (2/10 - 4/6)

CA row crop RLF

Monterey County,
California (Santa
Maria) (W23234)

77


-------
Scenario Group. Label Crop/Silc

Maximum
Application

Rates1
(Lbs. ai/A)

Applications per Crop
Cycle
(Minimum Days
before Re-treatment)

2001 - 2005 Peak
Application Date
(First and Last
Application Dates)

PRZM Scenario
Name

PRZIM Scenario
Meteorological
Station

45. Anise

Air: .9375
Other: .9375

7(7)

9/1 (8/10 - 9/23)

CA row crop RLF

Monterey County,
California (Santa
Maria) (W23234)

46. Strawberry

Air: 2
Other: 2

6(6)

6/11 (5/27 - 6/26)

CA strawberry
(non plastic) RLF

Santa Maria, CA (W
23273).

47. Sugar Beet

Air: 1.875
Other: 1.875

5(7)

10/16 (10/2 - 10/30)

CA sugarbeet OP

Fresno, California
(W93193).

48. Tomato

Air: 3.5
Other: 3.5

5(5)

7/9 (6/29 - 7/19)

CA tomato STD

Fresno, California
(W93193).

49. Okra

Air: 1.5
Other: 1.5

6(6)

6/22 (6/7 - 7/7)

CA tomato STD

Fresno, California
(W93193).

51. Sorghum

Air: 1.5
Other: 1.5

3(7)

7/27 (7/20 - 8/3)

CA wheat RLF

Fresno, CA (W93193)

52. Barley, Cereal Grains, Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

3(7)

3/30 (3/23 - 4/6)

CA wheat RLF

Fresno, CA (W93193)

53. Gooseberry

Air: 16
Other: 16

4(6)

7/1 (6/22 - 7/10)

CA wine grapes
RLF

San Francisco, CA
(W23234)

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

4(6)

7/1 (6/22 - 7/10)

CA wine grapes
RLF

San Francisco, CA
(W23234)

55. Blueberry

Air: 2.5
Other: 2.5

4(4)

9/2 (8/27 - 9/8)

CA wine grapes
RLF

San Francisco, CA
(W23234)

56. Caneberries and Currant

Air: 2
Other: 2

4(6)

7/1 (6/22 - 7/10)

CA wine grapes
RLF

San Francisco, CA
(W23234)

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

8(6)

7/1 (6/8 - 7/24)

CA wine grapes
RLF

San Francisco, CA
(W23234)

58. Mint and Spearmint

Air: 1
Other: 1

3(7)

7/29 (7/22 - 8/5)

OR mint STD

Salem, OR (W24232)

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

3(7)

6/11 (6/4-6/18)

Rice Guidance

NA

61. Water Cress

Air: 2
Other: 2

5(5)

9/10(8/31-9/20)

Rice Guidance

NA

78


-------
Scenario Group. Label Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Applications per Crop
Cycle
(Minimum Days
before Re-treatment)

2001 - 2005 Peak
Application Date
(First and Last
Application Dates)

PRZM Scenario
Name

PRZM Scenario
Meteorological
Station

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine (Seed
Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

3(10)

10/29(10/19-11/8)

CA forestry RLF

Arcata/Eureka, CA
(W24283)

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs (with Human
or Wildlife Use), Lakes/Ponds/Reservoirs (without
Human or Wildlife Use), Polluted Water, and
Swamps/Marshes/W etlands/Stagnant Water

Air: .6
Other: .6

5(10)

Not needed for
scenarios based on
rice guidance.

Rice Guidance

NA

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

5(5)

7/27 (7/17 - 8/6)

CA Nursery

San Diego, CA
(W23188)

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use), Urban
Areas, and Wide Area/General Outdoor Treatment
(Public Health Use)

Air: .6119
Other: .1361

10(7)

5/1 (3/30 - 6/1)

CA impervious
RLF

San Francisco, CA
(W23234)

Residential. Household/Domestic Dwellings
Outdoor Premises, Ornamental and/or Shade Trees,
Ornamental Herbaceous Plants, Ornamental Lawns
and Turf, Ornamental Non-flowering Plants,
Ornamental Woody Shrubs and Vines, and Urban
Areas

Other: ,253

10(7)

5/29 (4/29 - 6/28)

CA residential
RLF

San Francisco, CA
(W23234)

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

3(10)

6/1 (5/22-6/11)

CA right of way
RLF

Santa Maria, CA (W
23273).

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

6(10)

5/23 (4/28 - 6/17)

CA turf RLF

San Francisco, CA
(W23234)

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

79


-------
3.2.1.3 Aquatic Estimated Environmental Concentrations

Aquatic EECS were estimated using PRZM/EXAMS except for scenarios involving
direct application to water. Two EECs are given for each of the scenario groups listed in
column 1 of Table 9. The first, labeled "air", (column 2) is for scenarios based on
malathion applications made using aerial and air-blast methods, which are modeled with
an assumption of 5% spray drift according to EFED policy. The second, labeled "other",
is for scenarios based on malathion applications made using methods other than aerial
and air-blast methods, which are modeled with an assumption of 1% spray drift according
to EFED policy.

For each scenario (e.g., the air scenario from the almond scenario group), 3 EECs are
calculated. Peak EECs are the 90th percentile concentration of the highest annual
concentrations estimated over the time period simulated by each PRZM scenario
(typically, 25 to 30 years and based on the length of meteorological record available for
the locality simulated). The 21-day EECs are the 90th percentile of the annual maximum
21-day average concentrations estimated over the time period simulated by each PRZM
scenario. Similarly, 60-day EECs are similar to 21-day EECs but over a 60-day averaging
period.

Within most scenario groups, air EECs will be higher due to the higher spray drift
contribution if the application rates are the same for air and other application methods.
For some agricultural scenario groups (5, 6, 19, 20, and 23), however, the application
rates are higher for other application methods than air application methods. For these
scenario groups, whether the air or other scenarios are higher depends on whether the
additional EEC contribution from the higher other application rate is greater than the
EEC contribution from the higher drift fraction. Only 1 scenario group, public health has
a lower other application rate than the air application rate, which produces much lower
other EECs than air EECs.

Further examination of the malathion EECs indicated that many of the EECs were almost
solely due to the spray drift contribution. Because this observation has ramifications for
the interpretation of the risk assessment, the percentage of the malathion EEC due to drift
was estimated by running PRIZM EXAMS with the appropriate spray drift fraction and
without the spray drift contribution (spray drift fraction set to 0%) for each scenario.
Percent spray drift contribution was calculated as the difference between the with and
without spray drift EECs divided by the with EEC times 100 (to get a percentage).
Because the with and without spray drift EECs may occur at different times, this
calculation produces a minimum estimate of percentage drift contribution. (The
calculation would be exact only if the peak, 21-day, and 60-day EECs occurred at the
same time for both the with and without spray drift EECs.)

80


-------
Table 9. PRZM/EXAMS estimated environmental concentrations (EECs) for malathion (estimate includes drift component) and maloxon (drift
calculated separately). Maloxon application rate is assumed to be 10.7% of malathion application rate. Maloxon as an impurity in drift is assumed to be 0.1% of
malathion in drift.



Maximum

Estimated Environmental Concentrations (EECs)



Malathion

IMalathion EEC (jig/L)

Maloxon EEC (ug/L)



Application

(% Drift Contribution to EEC)

Degradatc Fraction2

Impuritv Fraction3

Scenario Group: Crop/Site

Rates1
(Lbs. ai/A)

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine,
Trefoil, and Vetch

Air: 2
Other: 2

9.6 (57)
5.3 (21)

3.7 (71)
1.5 (32)

1.4 (72)
.58 (34)

0.81

0.20

0.076

<0.001
<001

<0.001
<001

<0.001
<001

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

52 (87)
13 (46)

23 (95)
5.5 (78)

18 (98)
3.8 (89)

1.3

.22

.076

.004
<001

.001
<001

<001
<001

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

43 (100)
8.6 (98)

18 (100)
3.6 (99)

6.5 (100)
1.3 (99)

.060

.014

.005

.004
<001

<001
<001

<001
<001

4. Chestnut

Air: 5
Other: 5

16 (99)
3.3 (97)

7.3 (100)
1.5 (99)

3.5 (100)
.70 (99)

.044

.011

.004

.001
<001

<001
<001

<001
<001

5. Almond

Air: 1.25
Other: 4

7.4 (51)
13 (14)

3.4 (68)
5(30)

1.3 (68)
1.9 (30)

.50
1.6

.16
.53

.062
.20

<001
<001

<001
<001

<001
<001

6. Date

Air: 1
Other: 2

2.9 (99)
1.1 (94)

.94 (99)
.38 (97)

.52 (100)
.21 (98)

.014
.027

.003
.007

.001
.002

<001
<001

<001
<001

<001
<001

7. Filbert (Hazelnut)

Air: .625
Other: .625

2.1 (100)
.43 (98)

.88 (100)
.18 (99)

.32 (100)
.066 (99)

.003

<001

<001

<001
<001

<001
<001

<001
<001

8. Avocado

Air: 9
Other: 9

31 (100)
6.1 (100)

9.3 (100)
1.9(100)

3.3 (100)
.66 (100)

.003

<001

<001

.003
<001

<001
<001

<001
<001

9. Citrus, Citrus Hybrids other than
Tangelo, Grapefruit, Kumquat, Lemon,
Lime, Orange, Tangelo, and Tangerines

Air: 25
Other: 25

97 (98)
20 (90)

45 (99)
9.1 (95)

17 (99)
3.5 (95)

.24

.056

.020

.007
.001

.002
<001

<001
<001

10. Amaranth - Chinese, Broccoli
(Unspecified, Chinese, and Raab),
Cabbage (Unspecified and Chinese),
Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel),
Horseradish, Kale, Kohlrabi, Mustard,
Mustard Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

8.9 (100)
1.8(100)

4.5 (100)
.91 (100)

3.2 (100)
.63 (100)

.005

.001

<001

<001
<001

<001
<001

<001
<001

81


-------


Maximum

Estimated Environmental Concentrations (EECs)



IMalathion

IMalathion EEC (jig/L)

Maloxon EEC (ug/L)



Application

(% Drift Contribution to EEC)

Dcjiradatc Fraction2

Impuritv Fraction3

Scenario Group: Crop/Site

Rates1
(Lbs. ai/A)

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Peak

21-dav

60-dav

11. Corn (Unspecified, Field, Pop, and
Sweet) and Millet (Foxtail)

Air: 1.5
Other: 1.5

7.9 (100)
1.6 (99)

2.1 (100)
.43 (99)

.76 (100)
.15 (99)

.024

.006

.002

<001
<001

<001
<001

<001
<001

12. Cotton

Air: 4
Other: 4

20 (74)
5.2 (0)

13 (95)
2.5 (75)

12 (98)
2.3 (91)

.97

.12

.041

.001
<001

<001
<001

<001
<001

15. Apricot

Air: 10
Other: 10

34 (100)
6.8 (100)

16 (100)
3.3 (100)

6.5 (100)
1.3 (100)

<001

<001

<001

.003
<001

<001
<001

<001
<001

16. Nectarine and Peach

Air: 9
Other: 9

29 (100)
5.9 (100)

13 (100)
2.6 (100)

5.2 (100)
1 (100)

.010

.002

<001

.003
<001

<001
<001

<001
<001

17. Cherry

Air: 8
Other: 8

29 (100)
5.8 (100)

15 (100)
2.9 (100)

8.1 (100)
1.6 (100)

<001

<001

<001

.002
<001

<001
<001

<001
<001

18. Fig

Air: 2.5
Other: 2.5

8.5 (100)
1.7 (100)

2.9 (100)
.58 (100)

1 (100)
.21 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

4.1 (100)
.98 (100)

1.9(100)
.46 (100)

1.7 (100)
.41 (100)

.003
.003

<001
<001

<001
<001

<001
<001

<001
<001

<001
<001

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

2.8 (99)
.56 (95)

1.5 (100)
.31 (98)

1.3 (100)
.27 (99)

.004
.009

<001
.002

<001
<001

<001
<001

<001
<001

<001
<001

21. Papaya

Air: .175
Other: .175

.65 (99)
.13 (95)

.36 (100)
.072 (98)

.31 (100)
.063 (99)

.001

<001

<001

<001
<001

<001
<001

<001
<001

22. Garlic and Leek

Air: 2
Other: 2

9.9 (50)
5.9(16)

3.6 (78)
1.4 (41)

2(85)
.61 (53)

.70

.12

.041

<001
<001

<001
<001

<001
<001

23. Grapes

Air: 2.75
Other: 27.47

9 (100)
18 (100)

2.5 (100)
4.9 (100)

.87 (100)
1.7 (100)

<001
<001

<001
<001

<001
<001

<001
.002

<001
<001

<001
<001

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

9.1 (100)
1.8(100)

4.4 (100)
.89 (100)

1.7 (100)
.34 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

27. Swiss Chard, Chervil, Endive
(Escarole), Lettuce, Head Lettuce, Leaf
Lettuce (Black Seeded Simpson, Salad
Bowl, Etc.), Orach (Mountain
Spinach), Parsley, Roquette (Arrugula),
Salsify, and Spinach

Air: 2
Other: 2

20 (33)
14 (9)

6.8 (58)
3.3 (15)

3.5 (72)
1.5 (33)

3.5

.75

.27

<001
<001

<001
<001

<001
<001

82


-------


Maximum

Estimated Environmental Concentrations (EECs)



IMalathion

IMalathion EEC (jig/L)

Maloxon EEC (ug/L)



Application

(% Drift Contribution to EEC)

Dcjiradatc Fraction2

Impuritv Fraction3

Scenario Group: Crop/Site

Rates1
(Lbs. ai/A)

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Peak

21-dav

60-dav

28. Peppermint

Air: 1
Other: 1

3.6 (100)
.73 (100)

1.8(100)
.36 (100)

.68 (100)
.14(100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

29. Eggplant

Air: 3.5
Other: 3.5

12 (94)
2.5 (70)

5.9 (98)
1.2 (88)

2.6 (98)
.61 (91)

.31

.061

.023

.001
<001

<001
<001

<001
<001

30. Pumpkin

Air: 2
Other: 2

6.9 (87)
1.4 (35)

3.2 (96)
.65 (78)

1.8 (97)
.39 (87)

.22

.037

.013

<001
<001

<001
<001

<001
<001

31. Cucumber, Cucurbit Vegetables,
Melons - Unspecified, Cantaloupe,
Honey dew, Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persian),
and Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

6.5 (87)
1.7 (48)

3.2 (95)
.66 (77)

1.8 (96)
.4 (81)

.26

.042

.016

<001
<001

<001
<001

<001
<001

32. Onion (Unspecified and Green),
Radish, and Shallot

Air: 2
Other: 2

7.9 (75)
3.2 (39)

4(90)
1.1 (64)

2.3 (94)
.55 (75)

.36

.072

.026

<001
<001

<001
<001

<001
<001

33. Potato - White/Irish

Air: 3
Other: 3

9.8 (100)
2 (100)

4.1 (100)
.82 (100)

2.4 (100)
.48 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

34. Turnip

Air: 2.5
Other: 2.5

8.5 (100)
1.7 (100)

4 (100)
.79 (100)

2.3 (100)
.46 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

35. Parsnip and Rutabaga

Air: 2
Other: 2

6.1	(100)

1.2	(100)

2.3 (100)
.45 (100)

1.3 (100)
.26 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

36. Sweet Potato

Air: 1.875
Other: 1.875

5.9 (94)
1.2 (72)

1.7 (97)
.36 (86)

.61 (97)
.13 (87)

.023

.004

.001

<001
<001

<001
<001

<001
<001

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland,
Sudangrass, and Timothy

Air: 1.25
Other: 1.25

8.5 (100)
1.7 (100)

2.2 (100)
.45 (100)

.77 (100)
.16(100)

.001

<001

<001

<001
<001

<001
<001

<001
<001

40. Beets, Cowpea/Blackeyed Pea, and
Peas (Unspecified and Field)

Air: 2.5
Other: 2.5

8.9 (100)
1.8(100)

4.5 (100)
.91 (100)

2.7 (100)
.53 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

41. Carrot (Including Tops), Celtuce,
Fennel, and Pepper

Air: 2
Other: 2

8.3 (99)
1.7 (96)

5 (100)
1(99)

2.9 (100)
.58 (99)

.065

.015

.005

<001
<001

<001
<001

<001
<001

83


-------


Maximum

Estimated Environmental Concentrations (EECs)



IMalathion

IMalathion EEC (jig/L)

Maloxon EEC (ug/L)



Application

(% Drift Contribution to EEC)

Dcjiradatc Fraction2

Impuritv Fraction3

Scenario Group: Crop/Site

Rates1
(Lbs. ai/A)

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Peak

21-dav

60-dav

42. Beans, Beans - Dried-Type, Beans -
Succulent (Lima), and Beans -
Succulent (Snap)

Air: 1.75
Other: 1.75

6.5 (100)
1.3 (100)

3 (100)
.59 (100)

1.1 (100)
.22 (100)

.002

<001

<001

<001
<001

<001
<001

<001
<001

43. Celery

Air: 1.5
Other: 1.5

9.5 (42)
6.3 (13)

2.8 (59)
1.4 (20)

1(60)
.53 (23)

.88

.19

.066

<001
<001

<001
<001

<001
<001

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

9(29)
6.9 (8)

4.2 (60)
2.2 (21)

3.2 (78)
1.2 (41)

1.0

.28

.12

<001
<001

<001
<001

<001
<001

45. Anise

Air: .9375
Other: .9375

3.3 (98)
.67 (89)

1.7 (99)
.34 (95)

1.4 (100)
.27 (98)

.047

.011

.004

<001
<001

<001
<001

<001
<001

46. Strawberry

Air: 2
Other: 2

7.8 (100)
1.6 (100)

4.6 (100)
.92 (100)

2.7 (100)
.53 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

47. Sugar Beet

Air: 1.875
Other: 1.875

10 (65)
4.8 (26)

3.9 (79)
1.3 (36)

2.3 (87)
.69 (57)

.82

.17

.062

<001
<001

<001
<001

<001
<001

48. Tomato

Air: 3.5
Other: 3.5

12 (100)
2.4 (100)

5.7 (100)
1.1 (100)

2.4 (100)
.48 (100)

.003

<001

<001

.001
<001

<001
<001

<001
<001

49. Okra

Air: 1.5
Other: 1.5

5.1 (100)
1(99)

2.5 (100)
.5 (100)

1.3 (100)
.27 (100)

.002

<001

<001

<001
<001

<001
<001

<001
<001

51. Sorghum

Air: 1.5
Other: 1.5

4.6 (100)
.93 (100)

1.7 (100)
.35 (100)

.63 (100)
.13 (100)

.001

<001

<001

<001
<001

<001
<001

<001
<001

52. Barley, Cereal Grains, Oats, Rye,
and Wheat

Air: 1.25
Other: 1.25

12 (30)
8.7 (8)

4.4 (43)
2.9(12)

1.8 (48)
1.1 (16)

.98

.33

.12

<001
<001

<001
<001

<001
<001

53. Gooseberry

Air: 16
Other: 16

61 (100)
12 (100)

32 (100)
6.4 (100)

14 (100)
2.7 (100)

<001

<001

<001

.005
<001

.001
<001

<001
<001

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and Raspberry
(Black - Red)

Air: 4
Other: 4

15 (100)
3 (100)

8 (100)
1.6 (100)

3.4 (100)
.68 (100)

<001

<001

<001

.001
<001

<001
<001

<001
<001

55. Blueberry

Air: 2.5
Other: 2.5

11 (100)
2.3 (99)

5.6 (100)
1.1 (100)

2.1 (100)
.42 (100)

.024

.006

.002

<001
<001

<001
<001

<001
<001

56. Caneberries and Currant

Air: 2
Other: 2

7.6 (100)
1.5 (100)

4 (100)
.8 (100)

1.7 (100)
.34 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

84


-------
Maximum

Estimated Environmental Concentrations (EECs)

Malathion

Malathion EEC (jig/L)

Maloxon EEC (ug/L)

Application

(% Drift Contribution to EEC)

Dcjiradatc Fraction2

Impuritv Fraction3

Scenario Group: Crop/Site

Rates
(Lbs. ai/A)

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Peak

21-dav

60-dav

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

2.9 (100)
.58 (100)

1.7 (100)
.33 (100)

1.3 (100)
.25 (100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

58. Mint and Spearmint

Air: 1
Other: 1

3.4 (99)
.68 (97)

1.5 (100)
.3 (98)

.57 (100)
.12(99)

.021

.005

.002

<001
<001

<001
<001

<001
<001

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

1404
(N.A.)

313 (N.A.)

110 (N.A.)

.15

.034

.012

N.A.

N.A.

N.A.

61. Water Cress

Air: 2
Other: 2

1797
(N.A.)

401 (N.A.)

141 (N.A.)

.19

.043

.015

N.A.

N.A.

N.A.

Non-agricultural Uses

Forestry. Christmas Tree Plantations,
Pine (Seed Orchard), and Slash Pine
(Forest)

Air: 3.2
Other: 3.2

56 (14)
50(4)

15(19)
12(4)

6.5 (34)
4.7 (9)

6.2

1.5

.55

<001
<001

<001
<001

<001
<001

Mosquito Control. Intermittently
Flooded Areas/Water,
Lakes/Ponds/Reservoirs (with Human
or Wildlife Use),
Lakes/Ponds/Reservoirs (without
Human or Wildlife Use), Polluted
Water, and

Swamps/MarshesAV etlands/Stagnant
Water

Air: .6
Other: .6

539 (N.A.)

120 (N.A.)

42 (N.A.)

.058

.013

.005

N.A.

N.A.

N.A.

Nursery. Outdoor Nursery

Air: 2.254
Other: 2.254

8.7 (99)
1.7 (94)

4.6 (100)
.92 (98)

2 (100)
.4 (98)

.021

.003

.001

<001
<001

<001
<001

<001
<001

Public Health and Medfly Control.

Nonagricultural Areas (Public Health
Use), Urban Areas, and Wide
Area/General Outdoor Treatment
(Public Health Use)

Air: .6119
Other: .1361

15 (14)
3(3)

7.3 (17)
1.4 (4)

3.7 (33)
.61 (9)

3.4
.75

1.6
.34

.67
.15

<001
<001

<001
<001

<001
<001

85


-------


Maximum

Estimated Environmental Concentrations (EECs)



Malathion

Malathion EEC (fig/L)

Maloxon EEC (ug/L)



Application

(% Drift Contribution to EEC)

Dcgradatc Fraction2

Impuritv Fraction3



Rates1



















Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Peak

21-dav

60-dav

Residential. Household/Domestic





















Dwellings Outdoor Premises,





















Ornamental and/or Shade Trees,





















Ornamental Herbaceous Plants,
Ornamental Lawns and Turf,

Other: ,25s

.18(98)

.098 (99)

.096 (100)

.001

<001

<001

<001

<001

<001

Ornamental Non-flowering Plants,
Ornamental Woody Shrubs and Vines,





















and Urban Areas





















Rights-of-way. Nonagricultural Rights-
of-way/Fencerows/Hedgerows and
Nonagricultural Uncultivated
Areas/Soils

Air: .9281
Other: .9281

3 (100)
.59 (100)

1.2 (100)
.25 (100)

.62 (100)
.12(100)

<001

<001

<001

<001
<001

<001
<001

<001
<001

Turf. Golf Course Turf
(Bermudagrass)

Air: 1.25
Other: 1.25

4 (100)
.8 (98)

1.8(100)
.36 (99)

1.6 (100)
.33 (100)

.005

.001

<001

<001
<001

<001
<001

<001
<001

"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2Maloxon application rate is assumed to be 10.7% of malathion application rate.

3	Maloxon as an impurity in drift is assumed to be 0.1% of malathion in drift.

4	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

5Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

86


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Malathion EECs for direct application to water scenario groups (59-rice and wild rice,
60-water cress, and mosquito control) were calculated using the methods documented in
EFED's Rice Guidance document. Because the application rates for air and other
application methods are the same for these scenarios and spray drift is not a factor in
direct applications, only 1 set of peak, 21-day, and 60-day EECs are given for these
scenario groups {i.e., both air and other scenarios generate the same numbers).

EECs are difficult to calculate using PRZM/EXAMS for maloxon. Because maloxon is
both an impurity of malathion (estimated as 1% of malathion applied) as well as a
degradate (10.7% of malathion applied), both the impurity and degradate fractions should
contribute to maloxon EECs through runoff and groundwater pathways, but only the
impurity should contribute through the spray drift pathway. If maloxon is modeled as
being directly applied at 10.7% of malathion, the spray drift fraction for the impurity
needs to be 4.7 x 10"3 to simulate 1% impurity in a spray drift fraction of 5% (0.01 x 0.05
/ 0.107) or 9.3 x 10"3 to simulate the 1% spray drift fraction (0.01 x 0.01 / 0.107). Because
PRZM/EXAMS is not designed to accept such small spray drift fractions (there are not
enough digits allocated in the PRZM input files to allow representation of such small
numbers in either decimal or scientific notation), the impurity and degradate fractions of
the maloxon EECs had to be estimated separately.

To model the degradate in PRZM/EXAMS, maloxon was applied at 10.7% of the
malathion application rate with a spray drift fraction of 0% (no spray drift). Because
spray drift assumptions do not apply to the degradate fraction, only 1 set of peak, 21-day,
and 60-day EECs are given per scenario group {i.e., both air and other scenarios generate
the same numbers) except in those cases where the air and other application rates differ.

To model the impurity in PRZM/EXAMS, maloxon was applied at 1% of the malathion
application rate with a 5 or 1% spray drift fraction for air (aerial and air-blast application
methods) or other (other application methods), respectively.

3.2.2 Effect of Application Timing on Aquatic EECs

The application date can have a major impact on the aquatic EECs produced. This is
because the application time period (the simulated first through last application dates)
may cover only a small portion of the time period over which malathion is applied in
California (Figure 9) or can be legally applied {e.g., year-round for labels that do not have
temporal restrictions). Malathion is applied in every month of the year (Figure 2).

Because rain is more frequent in the winter for many of the scenarios while the peak
malathion applications tend to occur in the summer, many of the scenarios will generate a
much lower runoff contribution to EEC than would happen during other earlier or later
times of the year when malathion is being applied to that use.

Figure 10 shows the affect of application date on malathion EECs produced by
PRZM/EXAMS for the alfalfa scenario. During the summer months, the EECs are due
almost solely to spray drift. During the winter months, when runoff and groundwater
contributions occur, the EECs are much higher. Because the drift assumptions do not

87


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vary over time, the summer months without the contribution of runoff and groundwater
contributions produce the lowest EECs.

Calendar Date

Figure 10. Variation in peak (blue) and maximum average 21-day (green) and 60-day (red)
PRZM/EXAM estimated environmental concentrations (EECs) for malathion across a range of
application dates. For comparison, a moving average of the CaDPR daily application malathion
applied to alfalfa (solid black line) and the first and last application dates used in the PRZM model
are shown (vertical dashed lines).

2700

2250

1800

1350

900

450

¦s

"B.
a.
<

c

o

For most uses, the peak malathion application time is during the summer when EECs will
be lowest. Similar to alfalfa (Figure 10), however, applications of malathion often occur
outside of this peak application period. If these off-peak applications occur when runoff
and groundwater are more likely to occur, the EECs generated for the peak application
period may understate the EECs from off-peak applications and therefore, understate the
risk to the CRLF from malathion use.

3.2.3 Surface Water Monitoring Data

Surface water monitoring data are presented from four monitoring programs. Two
programs, California Department of Pesticide Regulation (CaDPR) and U.S. Geological
Survey's National Water Quality Assessment (NAWQA), analyzed surface water
samples for malathion in California, but were not targeted to malathion applications (non-
targeted). Non-targeted monitoring programs are not designed to sample specifically in
the vicinity of malathion applications and sampling is not timed to coincide specifically
with malathion applications. These programs provide information about typical or
average malathion concentrations and the general distribution of concentrations over the
region, time period, and population of sites sampled. The PRZM/EXAMS EECs should,
in general, be higher than these values with only the upper end of the distribution of non-
targeted malathion concentration values approaching the PRZM/EXAMS EECs.

The other two USDA programs, the Boll Weevil Eradication Program (BWEP) and the
Mediterranean fruit fly (medfly) control effort, are specifically designed to research the

88


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effects of malathion applications (targeted monitoring). Because targeted monitoring
specifically samples water bodies expected to be most impacted by the malathion
application being monitored, the after application samples should produce environmental
concentrations that are much closer to corresponding PRZM/EXAMS EECs.

The ranges of the PRZM/EXAMS EECs and non-targeted and targeted monitoring data
are compared in Section 3.2.5.

3.2.3.1 Non-targeted Monitoring

An evaluation of the surface water monitoring data was conducted to assess the
occurrence of malathion and maloxon in California. Surface water data were obtained
from the California Department of Pesticide Regulation

(http://www.cdpr.ca.gov/docs/sw/surfdata.htm) and U.S. Geological Survey's National
Water Quality Assessment (NAWQA) data warehouse

(http://water.usgs.gov/nawqa/data.htmn. Maximum site concentrations are calculated
from these data sets for comparison with PRZM/EXAMS EECs. Because these surface
water sampling programs are not targeted to malathion use areas and were not collected
at sites similar to the standard EXAMS pond (which is designed to present a high EEC
scenario), these sampling programs are not expected to produce concentrations as high as
the PRZM/EXAMS EECs. However, any agreement/disagreement can aid in
characterizing the uncertainty of the PRZM/EXAMS malathion EECs.

Frequency distributions of maximum site malathion concentrations are shown in Figure
11. At many sites, all samples collected were below the level of quantitation ("< LOQ" -
gray left-most bars in each graph of Figure 11). The maximum reported concentration of
malathion in the CaDPR data set is 6 |ig/L from the Colusa Basin Drain #5 in Colusa
County, CA, and 1.35 |ig/L from Warm Creek Near San Bernardino (site 11060400) in
San Bernardino, CA, for the USGS NAWQA data set. However, the interpretation of
these data sets is complicated because the LOQ varied between samples and over time.
The maximum LOQs were 1 and 0.15 |ig/L for the CaDPR and NAWQA data sets,
respectively. Therefore, additional sites may have had actual concentrations approaching
these LOQs in the samples that were collected that are listed as < LOQ. A total of 9
(CaDPR and NAWQA) sites had measured maximum concentrations in excess of 1 |ig/L
(the highest LOQ).

89


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Malathion Concentration (jig/L)

Malathion Concentration (jig/L)

Figure 11. Frequency distributions of (a) maximum site malathion concentrations for California
Department of Pesticide Regulation (CaDPR) and (b) U.S. Geological Survey's National Water
Quality Assessment (NAWQA) data sets.

The only maloxon concentration measured above the detection limit in either the CaDPR
or NAWQA data sets is 0.06 |ig/L from the Alamo River at All American Canal in
Imperial County, CA (from the CaDPR data set). The detection limits for maloxon varied
from 0.05 to 0.2 |ig/L for the CaDPR data set and from 0.008 to 0.09 |ig/L for the
NAWQA data set.

3.2.3.2 Targeted Monitoring

Boll Weevil Eradication Program: Malathion is water soluble and therefore has the
potential to be dissolved in rain water and transported in runoff water from application
sites. The Boll Weevil Eradication Program (BWEP) has monitored malathion in runoff,
standing (ponded), and moving surface water.

Malathion in runoff. Levels of malathion in runoff water have been examined mostly
using automatic runoff sampling equipment which consist of collection bottles with
funnels recessed in the ground at sites where runoff is expected. The amount of malathion
in runoff is expected to be affected by numerous variables including the soil type, half-
life on the particular soil, the amount of time between application and precipitation, the
amount of precipitation, and vegetation. Table 9 shows runoff monitoring data from five
treated cotton fields in the Boll Weevil program close to bodies of water. Sampling was
performed close to the field (10-25 feet) and closer to the water (40-135 feet from the
field). In most cases, malathion concentrations were lower when the interval between
application and rainfall was longer and/or distance from the field was farther. These
observations are expected since increasing the time interval since application allows for
more degradation to occur and longer runoff travel distances allow malathion to penetrate
soil and adsorb to soil particles before reaching surface water.

90


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Table 10. Field monitored runoffa from the Cotton Boll Weevil Control Program.





l-'ield RunolT Malathion (onccnlralion (njj/L)



Time from Application

( loser lo l-'ield

l-'arlhcr from l-'ield

l-'ield Number

lo Rain (l);i\s)

(Distance in l-'ccl)

(Distance in l-'ccl)

1806-502

1

9.3 (20')

1.9 (110')



3

7.5 (20')

3.5 (110')



6

>0.3 (20')

>0.3 (110')

1806-504

1

70 (20')

33 (40')



6

0.48 (20')

nd (40')

2025-187

2

0.42 (10')

0.53 (70')

2027-468

1

63 (15')

nd (135')



5

nd (15')

-

2100-200

18

4.2 (25')

3.8 (50')

502

3

1.1 (20')

nd (110')



7

0.5 (20')

nd (110')

504

1

10.9 (20')

nd (40')



3

41.8 (20')

15.6 (40')



7

146 (20')

93.5 (40')

7806

?

0.9 (0')

0.5 (45')



6

1.7 (0')

1.1 (45')



14

<0.3 (0')

0.3 (45')

325

2

8.54(15')

0.82 (60')



9

35.8(15')

16.2 (60')

aMalathion levels were measured in runoff water from cotton fields after rain events. Two sets of
measurements were made, one closer to the field and one farther from the field. Adapted from

Environmental Monitoring Report: 1997 Southeast Boll Weevil Eradication Program Sensitive Sites
(USDA 1997a) and Environmental Monitoring Report: 1996 Southeast Boll Weevil Eradication Program
(USD A 1996)
nd = none detected.

- = not sampled.

Spray drift contributions to standing water bodies: In monitoring projects the stability of
malathion in still water has been examined. A half-acre pond surrounded by cotton fields
with a 25 foot buffer was monitored for malathion (USDA 1993). Pesticide drift was
determined to be the most important mechanism of contamination of the pond. Residue
levels in the pond were lower before treatment (<0.1-0.44 |ig/L) and higher immediately
after malathion application (<0.33-91.4 |ig/L). In most cases malathion in the pond
degraded to <0.33 |ig/L within 7 days. Runoff was only a minor contributor of residue to
the pond but only two rainfalls occurred during the sampling period. The malathion in the
runoff samples collected were 9.75 and 76.3 |ig/L one day after the first and last
treatments, respectively. Other natural bodies of water within treatment areas, but not
intentionally receiving direct spray, showed no detectable levels of malathion 3-27 days
after applications ceased (USDA 1995).

Spray drift contributions to moving water bodies: The Boll Weevil Eradication Program
also assessed spray drift contributions to moving water bodies (Tables 10, 11, and 12).
Wide buffer strips (125-700 feet) with high vegetation appeared to reduce malathion drift
to sensitive areas to levels below detection while narrower and lower buffer afforded less
protection (Table 12). With aerial applications, 8 of 19 applications lead to higher aquatic
malathion concentrations, whereas only 1 of 10 ground applications resulted in higher

91


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malathion levels. (Aerial applications are more prone to drift than ground applications.)
Although increased malathion levels in the streams, rivers, and canals examined after
nearby treatments decreased rapidly, decreases are likely due primarily to the movement
of contaminated water downstream.

Table 11. Southeast Boll Weevil Eradication Program monitoring data of spray drift to adjacent
moving water (USDA 1993)".	



Application

Trcalmcnl Number

Downstream Malalhion ( onccnlralion



(Aerial/

(l);i\s since l.asl

.ug/kg (Minnies

jig/kg (Minnies

Sile: ( iiiiimeiils

(•round)

1 realmenl)

licforc 1 realmenl)

Al'lcr 1 realmenl)

McCall's Creek:

Aerial

1(?)

nd

nd

The creek was
separated from the
field (13.3 acre) by a
continuous 600-700'

Aerial

2(8)

nd

nd

Aerial

3(6)

nd

nd

Aerial

4(7)

nd

nd

buffer of 30-60' trees.

Aerial

5(7)

16.1 (60)

nd

North River: The

Ground

1(?)

-

nd

field (8.3 acre) is

Ground

2(5)

nd

nd

separated from the

Ground

3(7)

nd

nd

river by a continuous
buffer of mature
hardwoods and
moderately dense
understory
approximately 125'
deep.

Ground

4(6)

<0.33 (45)

<0.33 (45)

Ground

5(6)

<0.33 (0)

<0.33 (0-120)

Aerial

6(10)

1.54 (45)

1.44 (60)

Aerial

7(6)

<0.33 (0)

<0.33 (0-120)

Aerial

8(7)

1.77 (60)

1.46 (0)

Aerial

9(10)

0.42 (45)

0.55 (45)

Pursley Creek: The

Aerial

1(?)

nd

3.54 (135)

field (95.3 acre) was

Aerial

2(7)

nd

0.39 (120)

separated from the
creek by 100' of
mature hardwoods
with a dense

Aerial

3(7)

nd

1.03 (30)

Aerial

4(7)

nd

<0.33 (75-120)

Aerial

5(7)

6.63 (30)

3.80 (120)

understory.

Aerial

6(6)

nd

3.35 (150)

Stewart Creek: The

Ground

1(?)

nd

nd

field (19.2 acre) was

Ground

2(8)

<0.33 (60)

nd

separated from the

Aerial

3(7)

nd

7.69 (60)

creek by a 25' buffer

Aerial

4(5)

nd

3.16(75)

of low -lying kudzu

Ground

5(7)

0.52

<0.33 (0-240)

vegetation.

Ground

6(4)

0.51

10.89(15)



Ground

7(5)

<0.33

<0.33 (15, 105, 135-
250)



Aerial

8(6)

1.01

4.52 (60)



Aerial

9(12)

<0.33

3.49 (105)

a Malathion levels in moving water adjacent to cotton fields were measured before and after treatment.
Measurements were made downstream from the field every 15 minutes from one hour before until 2-3.25
hours after application. Application was made when wind was not blowing directly over the water.

92


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Table 12. Texas Lower Rio Grande Valley Boll Weevil Eradication Program monitoring data of
spray drift to adjacent moving water (USDA 1995a)".	



Downstream IVIalathion Concentration

Site/Comments

Aerial/
Ground

Treat-
ment #

jig/kg (Minutes
Before Treatment)

jig/kg (Minutes
After Treatment)

#204060311/

Canal 200' from treated field.

?

1

0.324 (15)

0.297 (15)

?

2

4.89(15)

7.26 (30)

#2144070704 Canal 40' from
treated field

?

1

6.38 (30)

11.4 (0)

?

2

2.27 (45)

1.87 (0)

#212080704/ Canal 150'
from treated field

?

1

4.81 (45)

4.15 (30,120)

?

2

2.4 (30)

4.37 (120)

?

3

5.92 (45)

4.21 (0)

aMalathion levels in moving water adjacent to cotton fields were measured before and after treatment.
Measurements were made downstream from the field every 15 minutes from one hour before until 2-3.25
hours after application. Application was made when wind was not blowing directly over the water.

Table 13. Southern Rolling Plains Boll Weevil Eradication Program monitoring data of spray drift to
adjacent moving water (USDA 1994-5)".		



Peak Downstream Malathion Concentration

Site/Comments

Method of
Application

Treat-
ment #

jig/kg (Minutes
Before Treatment)

jug/kg (Minutes
After Treatment)

Concho County Stream

(10303-1408)
Samples collected 0.25
miles downstream

Hi-Boy

1

0.849 (15)

6.95 (105)

Mist blower

2

0.695 (45)

86.9 (225)

Mist blower

3

0.273 (45)

0.503 (210)

Concho River
(10708-2707)
Samples collected 0.25
miles downstream

Mist blower

1

0.676 (15)

0.813 (0)

Mist blower

2

0.871 (60)

0.589 (150)

Mist blower

3

2.24 (60)

7.45 (15)

aMalathion levels in moving water adjacent to cotton fields were measured before and after treatment.
Measurements were made downstream from the field every 15 minutes from one hour before until 2-3.25
hours after application. Application was made when wind was not blowing directly over the water.

Monitoring data suggests that urban malathion use poses the highest risk of
contaminating surface water. However, use data are not available to correlate with
monitoring data to determine which particular uses have the greatest impact. Total usage
and use rates in specific cities are also unavailable. Targeted urban monitoring and
preliminary fate experiments suggest however that malathion contacting anthropogenic
surfaces is likely to convert to the oxon and has a high runoff potential.

Mediterranean fruit fly (medfly) control effort: Malathion concentrations in water in and
around urban medfly treatment areas in California and Florida have been measured.
Although a risk assessment of malathion use for medfly control is not included in this
document (these generally fall under section 18 local need uses), the monitoring studies
associated with this use provide information on malathion fate and transport in residential
settings. In urban areas not involved in medfly control measures, malathion can be found
in runoff water at higher levels than agricultural areas. A monitoring report by United
States Geological Survey showed that higher residues are found in urban areas. In this

93


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analysis of 11 urban streams (604 samples) and 37 agricultural streams (1530 samples)
malathion concentrations were higher in the urban tributaries.

It is likely that proposed residential uses will result in aquatic contamination. Residential
malathion uses include outdoor home and garden, public park, and commercial use as
well as residential mosquito control. Home use formulations may be applied as a "...
spray to lower foundation of house, patios and garbage cans ... along fences; to firewood
piles; and other infested areas" (Ortho Malathion 50 Plus Insect Spray label). Malathion
on the surfaces described on the this label is likely to persist longer and be more available
for runoff than malathion on soil. Fyfanon ULV formulation is applied at 0.2 - 0.23 lbs/A
aerially at 150 mph over residential areas for mosquito control. In addition to covering
anthropogenic surfaces it is likely that moderate sized bodies of water receive direct
spray during normal aerial mosquito control use. In medfly treatments, malathion is
mixed with a bait mixture and applied aerially at nearly the same rate as in mosquito
control but with large buffers (up to 200 feet). Medfly applications in residential areas
provide useful information on the fate and transport of malathion in these settings, but it
is very likely that the smaller particles produced from the ULV formulation used in
mosquito control results in more drift than the baited mixture for medfly. Thus, medfly
monitoring data of drift will be expected to underestimate drift from ULV mosquito use.

In medfly control efforts larger bodies of water are "flagged" to avoid direct malathion
treatment. Thus, contaminated water bodies presumably received insecticide residues by
drift and runoff. On average, reservoirs in the treatment area which were flagged to avoid
direct spray contained 0.16 |ig/L before treatments and 2.59 |ig/L immediately after
treatment (Table 14). All waters in and around the treatment area, whether protected or
not, showed increased malathion levels immediately after treatment. In general,
applications were performed approximately weekly with no noted aggregate
accumulation of malathion in water.

Rainwater runoff in California medfly treatment area contributed greatly to malathion
levels in a stream passing through the treatment area. After precipitation, inflow into the
treatment area contained less than 1 |ig/L while downstream water contained up to
203 |ig/L malathion. Maxima in 1990 and 1981 were 44.1 and 583 |ig/L (CaEPA1996).

94


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Table 14. Malathion levels in bodies of water in relation to medfly control spraying3.



Treat-

Days

Malathion (ug/L)

Maloxon (ug/L)



since















ment

Last

No. of

Before

After

No. of

Before

After

Site

No.

Spray

Samples

(Std. Err.)

(Std. Err.)

Samples

(Std. Err.)

(Std. Err.)



1

*

14

*

4.94 (2.71)

*

*

*

Unprotected1
natural
waters

2

9

6-16

0.20 (0.05)

18.66 (5.81)

1

*

18.0 (*)

3

11

13-15

1.50 (1.17)

9.78 (2.47)

*

*

*

4

7

14-15

.48 (.13)

95.4 (53.2)

1-2

0.64 (*)

1.9 (0.20)

5

7

13-14

.66 (.12)

4.97 (1.05)

4-5

.19(0.046)

.63 (.17)



6

7

11-12

.57 (.20)

23.4(11.6)

1-4

.90 (*)

.35 (.10)

Average

-

8.2

-

.68 (.33)

26.19 (12.8)

-

-

-



1

*

20

.091 (.058)

.33 (.078)

*

*

*

Protected2
natural
waters

2

9

20

.12 (.07)

.56 (.10)

*

*

*

3

11

19-20

.056 (.028)

.90 (.15)

*

*

*

4

7

14-15

.12 (.07)

1.25 (.22)

*

*

*

5

7

20-22

.040 (.019)

2.10 (.41)

1

*

.40 (*)



6

7

15-19

.053 (.040)

.39 (.089)

2

*

.45 (.25)

Average

-

8.2

-

.080 (.048)

.92 (.17)

-

-

-



2

9

2

.18 (.03)

.75 (.65)

1

*

2.7 (*)

Flagged
reservoirs

3

11

2

*

.50 (.10)

*

*

*

4

7

19-20

.033 (.024)

8.39(3.81)

2

*

.92 (.29)

5

7

10-12

.51 (.30)

1.90 (.94)

*

*

*



6

7

8

.075 (.062)

1.42 (.41)

1

•1 (*)

.83 (*)

Average

-

8.2

-

.16 (.083)

2.59 (1.18)

-

-

-

Reservoirs
outside
treatment
area

2

9

2

.05 (.05)

.34 (.07)

*

*

*

3

11

2-4

.10 (.10)

1.0 (.55)

*

*

*

4

7

10

.03 (.03)

.30 (.16)

*

*

*

5

7

10

.036 (.024)

.14 (.058)

1

1.3 (*)

*

6

7

8-10

.18 (.074)

.21 (.087)

*

*

*

Average

-

8.2

-

.079 (.056)

.40 (.19)

-

-

-

a Malathion was measured immediately before and after spraying a bait formulation at ~0.17 lbs ai/A from
an altitude of 300 feet. This data was adapted from A Characterization of Sequential Aerial Malathion
Applications in the Santa Clara Valley of California (CaEPA 1981).

1	Unflagged and within the treatment area.

2	Flagged to avoid treatment or outside the treatment area.

* No data.

95


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Table 15. Malathion level in 29 ponds in Florida exposed to direct (unprotected aquatic sites) or
indirect (protected aquatic sites) malathion spray in medfly control".	



Before Application

After Application



Number of

Average

St. Dev.

Number of

Average

St. Dev.

site

Samples

(Hg/L)

(Hg/L)

Samples

(Ug/L)

(jig/L)

Unprotected Aquatic Sites

Fairgrounds

8

0.06

0.07

9

1.20

1.54

Palm river

9

0.78

0.72

7

3.97

3.24

Ragen Park

6

14.12

14.17

7

35.75

27.50

University Square Mall

7

0.04

0.07

7

3.77

3.67

Pond Lake

6

4.11

4.35

10

9.25

11.78

Bloomingdale Area

9

0.81

0.71

9

6.12

7.22

Carrolwood

7

1.05

2.01

6

4.77

3.75

Town and Country

6

1.10

1.15

5

6.88

3.07

McDill Site

5

0.12

0.06

4

5.20

2.33

Brandon Town Center

5

3.50

1.86

8

65.71

149.18

Lowry Zoo

7

0.14

0.22

6

1.55

1.86

Sun 'n Fun

8

0.09

0.07

10

7.28

15.48

Hamilton Creek

6

0.61

0.41

7

10.74

19.51

Eagle Lake

7

1.60

2.29

7

13.99

10.39

Protected Aquatic Sites

Moore's lake

10

0.36

0.78

10

0.76

1.66

Lake Weeks

12

0.69

0.67

11

4.85

4.08

Lake Valrico

12

0.03

0.06

11

2.84

6.71

Lake Kathy

12

0.43

0.91

11

5.91

9.15

Lake Walden

6

0.21

0.14

6

2.21

2.37

Alafia River

6

0.13

0.17

6

1.93

4.06

Hillsborough River

8

0.35

0.39

8

5.02

9.13

Piatt Lake

2

0.08

0.08

2

0.85

0.15

Lake Magdalene

2

0.08

0.08

2

0.80

0.20

Lake Carroll

2

0.31

0.16

2

1.65

0.55

Crystal Lake

9

0.02

0.05

9

0.46

0.74

Lake Horney

10

0.03

0.06

9

3.47

3.86

Banana Lake

7

0.21

0.33

7

2.48

3.97

Crews Lake

7

0.23

0.19

7

0.82

0.96

a Samples were collected within 18 hours of approximately weekly treatments of 0.15 lbs/A. Unprotected
bodies of water were ~0.1 miles in length and may have received runoff from surrounding watersheds.

Protected waters were rivers or larger lakes. Statistically, values below the detection limit (0.1 |ig/L) were
treated as 0 |ig/L and values below limit of quantitation (0.3 |ig/L) were treated as 0.15 |ig/L. The data was
adapted from the Environmental Monitoring Report: Cooperative Medfly Project Florida (USDA 1997b).

Residential settings are expected to be composed of numerous surfaces which may be
physically and biologically impervious to malathion. The relative quantities and effects of
adsorption and degradation on concrete, roofing, metal, and plastics is unknown in the
residential settings where malathion may be sprayed for medfly and mosquito control.
Monitoring results suggest that the residential surfaces increase availability of malathion
for runoff probably due to lack of microbial activity which decreases metabolism, less
water content which decreases hydrolysis, and little adsorption. Although the application
rate for mosquito control is low relative to agricultural use (0.20 - 0.6 lbs/A for aerial
mosquito control versus 0.175 - 27.47 lbs/A for agricultural pest control), application
over wide areas may be concentrated in storm drain systems along with malathion from
home and garden and commercial site use.

96


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The concentration factor appears to be greater in residential settings when comparing
residential and agricultural runoff. This is consistent with the results of several USGS and
USDA monitoring studies. Preliminary monitoring results for malathion in surface water
(USGS 1997) show malathion was detected above 0.01 |ig/L with a 2.61% frequency in
agricultural streams while in urban streams the frequency was 20.86%. The USDA
monitoring studies for boll weevil control show an average runoff concentration of
15.5 |ig/L (Table 11) while average downstream creek concentrations in the urban Santa
Clara Valley of central California were 177 |ig/L during 1981 malathion spraying for
medfly.

The highest levels of aquatic maloxon found in a search of available data were a result of
medfly control efforts in California (CaDFG 1982). The following table is derived from
the monitoring study during the malathion spraying in the Santa Clara Valley. Samples
were taken 2-3.5 hours after the first rainfall 6 days after the last application. These
runoff concentrations are much higher than agricultural runoff levels.

Table 16. Malathion and maloxon concentrations in creeks after malathion applications in the Santa
Clara Valley.		

Sampling Location

Average Concentration (Std. Dev.)

Malathion ((ig/L)

Maloxon ((ig/L)

Adobe Creek

50' Upstream

449 (17.7)

164 (33.2)

Drain

583 (40.3)

328 (18.4)

100' Downstream

361 (20.5)

169 (-)

Stevens Creek

50' Upstream

159 (-)

68.0 (-)

Drain

434 (73.5)

147 (4.2)

150' Downstream

156 (23.3)

68.0 (-)

Guadalupe Creek, Site 1

50' Upstream

1.9 (0.2)

0.8 (0.3)

Drain

142 (-)

147 (4.2)

150' Downstream

23.5 (2.1)

22.0 (-)

Guadalupe Creek, Site 2

50' Upstream

137 (25.4)

212 (9.2)

Drain

188(12.0)

250 (8.5)

150' Downstream

169 (6.4)

231 (8.5)

Fate data for malathion clearly show that its major routes of degradation are through
aerobic microbial metabolism and hydrolysis. Both of these routes are expected to be
lower on inert, dry surfaces; thus malathion persistence would be expected to be
increased. Malathion persistence on steel plates is extended relative to soil with only 15%
lost in two days (CaEPA 1996) compared to several soils on which 50% can be degraded
in 8 hours. Slowed malathion hydrolysis and metabolism is likely to result in increased
maloxon levels via abiotic oxidation. On the steel plate study mentioned previously,
maloxon accounted for 5% of the degradates, significantly higher than the maximum of
1.8% on soil reported by the registrant.

3.2.4 Air Monitoring

An evaluation of air monitoring data was conducted to assess the occurrence of malathion
and maloxon. Air monitoring data were obtained from the California Department of
Pesticide Regulation (Segawa, et al, 2003 and Kollman 2002). A review of the air

97


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monitoring data indicates that malathion was detected in trace quantities in an air
monitoring study in Lompoc City, Santa Barabara County (Segawa, et al, 2003). Air
concentrations of malathion were 7.6 ng/m3 for the highest one day average, 1.01 ng/m3
for the highest 3 day average, 0.54 ng/m3 for the highest 18 day average concentration.
Air concentrations of malathion were not reported in the California Pesticide Air
Monitoring Results: 1986-2000 (Kollman 2002). Additionally, air monitoring data for the
malathion degradation products was not found.

The potential impact of malathion air concentrations on surface water quality was
assessed for the standard water body. Air concentrations above the pond are assumed to
be the maximum reported air concentration in CA (7.6 ng/m3). The potential contribution
of volatile malathion was evaluated assuming different air volumes above the pond. Mass
loading of malathion was calculated assuming a complete rainwater "wash-out" from the
air space above the pond. Malathion water concentrations from atmospheric deposition of
volatile malathion are not expected to exceed 0.27 |ig/L. Using similar assumptions,
maloxon water concentrations from atmospheric deposition of volatile maloxon are not
expected to exceed 0.078 |ig/L.

3.2.5 A quatic Exposure Summary

PRZM/EXAMS EECs represent the total contribution of spray drift, runoff, and
groundwater flow paths. Because the application date for many of the scenarios is in the
summer when there is little runoff and groundwater contribution, many scenarios' EECs
are dominated by spray drift contributions. Table 9 provides estimates of the percentage
of the EEC contributed by drift for each use. Figure 12 compares these estimates of drift
contribution to EECs to the PRZM/EXAMS EECs produced for each use. These graphs
show little relation between percentage contribution from drift and total EEC (combined
contribution of drift, runoff, and erosion) even within PRZM/EXAMS scenarios from
similar locations (as indicated by the location from which meteorological data was
collected in Figure 12b).

98


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Aerial Applications (5% Spray Drift)

Ground Applications (1% Spray Drift)

u

uj
es

CJ
&

10

0.01

100

©X
eS
~-

10

!"s*
2^ 1

S N

s W 0.1

S
"H

20

40

60

SO



X







0

X *

o 1





~

A
A

X

~

%

~ 1

° D

°4

c

C

X





- X

X

O J

<> * ~ ~

~

o

~

~

o







+



~

b

X Arcata/Eureka, CA
~ Fresno County, CA
X Sacramento, CA
+ SanDiego County, CA

~ Bakersfield, CA
A Monterey County, CA
o Salem, OR
- Santa Maria, CA

100

Percentage EEC Contribution from Drift (%)

Figure 12. Comparison of PRZM/EXAMS estimated environmental concentrations (EECs) to the
percentage of EEC contributed from drift shows that many high aquatic EECs are largely, or almost
solely, attributable to drift alone (drift contribution for individual scenarios is listed in Table 9).

Figure 12 shows that some of the highest EECs are almost solely due to drift. Because
drift is a relatively uncomplicated exposure pathway compared to runoff and groundwater
pathways, there is correspondingly less uncertainty associated with the drift component
of the PRZM/EXAMS EECs.

The range of peak and maximum average 21-day and 60-day malathion EECs generated
by PRZM/EXAMS overlaps with, or is exceeded by, several of the previously-discussed
surface water monitoring data sets (Figure 13). As expected, the non-targeted (CaDPR
and USGS) data sets are lower, in general, than the PRZM/EXAMS EECs, but do show
considerable overlap in concentration ranges. Monitoring from the Boll Weevil
Eradication Program (a targeted monitoring program) shows concentration ranges that, in
general, equal or exceed the PRZM/EXAMS EECs for concentrations measured in
runoff, standing water (ponds), and in one study moving water. (The other 2 moving

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water studies found overlapping, but lower concentrations.) Monitoring from efforts to
control the Mediterranean fruit fly (another targeted monitoring program) shows
concentration ranges that are also, in general, equal to or exceed the PRZM/EXAMS
EECs for concentrations measured in unprotected waters (waters located within the aerial
treatment area). Protected waters from the medfly studies show lower concentrations than
unprotected waters, but concentrations that partially overlap the PRZM/EXAMS EECs.

PRZM/EXAMS EECs

Peak 5% Spray Drift (Figure 11a)
Peak 1% Spray Drift (Figure lib)
21-day 5% Spray Drift (Figure 11c)
21-day 1% Spray Drift (Figure lid)
60-day 5% Spray Drift (Figure lie)
60-day 1% Spray Drift (Figure 1 If)
Non-targeted Monitoring

CaDPR (F igure 10a)
USGS (Figure 10b)
Targeted (Boll Weevil Eradication Program)

Runoff (Close: Table 9)
Runoff (F ar: Table 9)
Standing Water (text)
Moving W ater (Table 10)
Moving W ater (Table 11)
Moving W ater (Table 12)
Targeted (Mediterranean Fruit Fly Control)

CA Protected Water (Table 13)
C A Unprotected Water (Table 13)
FL Protected Water (Table 14)
FL Unprotected Water (Table 14)
CA Unprotected Water (Table 15)











1





vvvvv

SI





'///J













N

S.





N

S.





N

s.





N

s.





N

s.





N

s.





N

s.





























N

s.





N

s.











0.1 1	10 100 1000 0.1 1	10 100 1000

Malathion Concentration (fig/L)	Maloxon Concentration (fig/L)

Figure 13. Comparison of PRZM/EXAMS estimated environmental concentrations (EECs) for
malathion and maloxon to non-targeted monitoring and targeted monitoring in agricultural (Boll
Weevil Control Program) and urban (Mediterrarainian fruit fly control) settings. (N.S. = not
sampled.)

(Aquatic uses in which malathion is intentionally applied directly to water - rice and wild
rice, water cress, and mosquito control - are not included in Figure 13. These uses,
because of the direct application to water, generate the highest EECs ranging from 540 to
1800 |ig/L.)

For maloxon, there is less data, but the PRZM/EXAMS EECs appear to be even lower
relative to the available targeted monitoring data. Again, the non-targeted monitoring
data are lower with only 1 sample having a measured concentration above the detection
limit.

This comparison between the PRZM/EXAMS EECs and the available surface water data
indicates the aquatic exposure assessment is not conservative (does not produce higher
EECs than are documented to occur in the environment that would produce a risk

100


-------
assessment that is protective of the CRLF). Though there are many potential
explanations, 2 explanations merit further exploration:

•	Malathion persistence may be under-estimated. One of the major routes of
malathion dissipation is hydrolysis. Under acidic conditions, malathion is
expected to be much more persistent. Often in environmental modeling, average
conditions are used to represent what is, in reality, a distribution of conditions.
The PRZM/EXAMS EECs are based on hydrolysis under neutral conditions. If
the actual environmental conditions are composed of a mosaic of micro-
environments having a distribution of pHs centered on a neutral pH, the
PRZM/EXAMS EECs would not account for the malathion and maloxon that
persist for extended periods in the more acidic micro-environments.

•	EFED's spray drift assumptions may be under-estimated. An assessment of drift
from malathion use was conducted for the Boll Weevil Eradication Program by
measuring off-target drift adjacent to aerial ULV malathion applications
(Pennsylvania State University 1993). Maximum and average spray drift fractions
were much higher than EFED's assumptions of 5% for aerial and air blast
application methods and 1% for other application methods.

Because many of the high PRZM/EXAMS EECs are due almost completely to spray drift
contribution, it is unlikely that the lack of conservatism is due to the PRZM/EXAMS
parameters or inputs related to the runoff and groundwater flowpaths.

3.3 Terrestrial Exposure Assessment

Similar to the aquatic exposure assessment, the terrestrial exposure assessment estimates
the environmental concentrations of malathion and maloxon to which terrestrial
organisms are expected to be exposed. The estimated exposure concentrations will be
used in subsequent sections to assess effects of terrestrial malathion exposure directly to
CRLF and indirectly to CRLF through habitat and prey. The TerrPlant model is used to
estimate terrestrial malathion and maloxon concentrations.

Again because the risk assessment is intended to be protective of the CRLF, the terrestrial
exposure estimates are based on conservative (protective) assumptions and, therefore,
should be higher than measured concentrations, but not unrealistically so.

3.3.1 Terrestrial Wildlife Exposure Modeling

EFED estimates exposure of birds and mammals to pesticides (Table 17) using the
Terrestrial Exposure Model (T-REX). (Small birds and mammals are prey items of the
CRLF. Therefore anything that directly impacts the population levels of CRLF prey items
represents a potential indirect effect on the survival of the CRLF.) T-REX uses the
Kenaga nomagram, as modified by Fletcher et al. (1994) to determine pesticide residue
concentrations on several categories of food items, then calculates the potential dose an
organism might receive from ingesting contaminated items using allometric equations.
Dose estimates are based on an upper bound dose and the assumptions that the organism
exclusively eats one type of food item and forages only in the treated and/or overspray

101


-------
areas. Dose based estimates for individual exposure scenarios vary from 3.97 to 11,548
mg/kg-bw for small birds and 0.74 to 9667 mg/kg-bw for small mammals.

102


-------
Table 17. Dietary- and dose-based estimated environmental concentrations (EECs) for small birds and Mammals. Small birds (approximately 20 g) and
small mammals (approximately 15 g) are prey items of the California Red-legged Frog. 	



Dictarv-bascd EECs (mg/kg of Food
Item)

Dose-based EECs (mg/kg-bw) for:
20 g Bird /15 g Mammal



1 1 Fruit/

Herbivores and Inscctivorcs

Granivo res

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

Agricultural Uses

1. Alfalfa, Clover, Lespedeza,
Lupine, Trefoil, and Vetch

Air: 2
Other: 2

679

311

382

42.4

773 / 647

354/297

435 /364

48.3 /40.4

N.A. / 8.99

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

6129

2809

3448

383

6981 / 5844

3199/2678

3927/3287

436/365

N.A. / 81.2

3. Pecan and Walnut
(English/Black)

Air: 12.5
Other: 12.5

5070

2324

2852

317

5774/4833

2646/2215

3248/2719

361/302

N.A. / 67.1

4. Chestnut

Air: 5
Other: 5

1987

911

1118

124

2263 / 1895

1037/868

1273 / 1066

141/118

N.A. / 26.3

5. Almond

Air: 1.25
Other: 4

507
1622

232
744

285
913

31.7
101

577 / 483
1848 / 1547

265 / 222
847 / 709

325/272
1039 / 870

36.1 /30.2
115/96.7

N.A. / 6.71
N.A. / 21.5

6. Date

Air: 1
Other: 2

380
576

174
264

214
324

23.8
36

433 /363
656 / 549

199 / 166
301 /252

244 / 204
369/309

27.1/22.7
41/34.3

N.A. / 5.04
N.A. / 7.63

7. Filbert (Hazelnut)

Air: 0.625
Other: 0.625

253

116

143

15.8

289/242

132/111

162/136

18/15.1

N.A. / 3.36

8. Avocado

Air: 9
Other: 9

3174

1455

1785

198

3615 /3026

1657 / 1387

2033 / 1702

226 / 189

N.A. / 42

9. Citrus, Citrus Hybrids other
than Tangelo, Grapefruit,
Kumquat, Lemon, Lime,
Orange, Tangelo, and
Tangerines

Air: 25
Other: 25

10,139

4647

5703

634

11,548/9667

5293 /4431

6495 / 5438

722 / 604

N.A./134

10. Amaranth - Chinese,
Broccoli (Unspecified,
Chinese, and Raab), Cabbage
(Unspecified and Chinese),
CanolaVRape, Cauliflower,

Air: 2.5
Other: 2.5

1019

467

573

63.7

1160/971

532/445

653 / 546

72.5/60.7

N.A. / 13.5

103


-------




Dietary-based EECs (mg/kg
Item)

of Food

Dose-based EECs (mg/kg-bw) for:
20 g Bird /15 g Mammal











Fruit/

Herbivores and Insectivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadlcat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

Collards, Corn Salad, Dock
(Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard
Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden
and Winter)





















11. Corn (Unspecified, Field,
Pop, and Sweet) and Millet
(Foxtail)

Air: 1.5
Other: 1.5

857

393

482

53.6

976/817

447/375

549 / 460

61/51.1

N.A. / 11.4

12. Cotton

Air: 4
Other: 4

3049

1397

1715

191

3473 / 2907

1592 / 1332

1953 / 1635

217/182

N.A. / 40.4

15. Apricot

Air: 10
Other: 10

4304

1973

2421

269

4902/4104

2247/ 1881

2757/2308

306/256

N.A. / 57

16. Nectarine and Peach

Air: 9
Other: 9

3874

1775

2179

242

4412/3693

2022 / 1693

2482 / 2077

276/231

N.A. / 51.3

17. Cherry

Air: 8
Other: 8

3580

1641

2014

224

4078/3413

1869 / 1565

2294 / 1920

255 /213

N.A. / 47.4

18. Fig

Air: 2.5
Other: 2.5

1090

499

613

68.1

1241 / 1039

569/476

698 / 584

77.6/64.9

N.A. / 14.4

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

565
678

259
311

318
381

35.3

42.4

644 / 539
772 / 647

295 / 247
354/296

362/303
434/364

40.2/33.7
48.3 /40.4

N.A. / 7.48
N.A. / 8.98

20. Guava, Mango, Plum, and
Prune

Air: 0.75
Other: 1.5

339
678

155
311

191

382

21.2
42.4

386 / 323
773 / 647

177 / 148
354/296

217/182
435 /364

24.1/20.2
48.3 /40.4

N.A. / 4.49
N.A. / 8.98

21. Papaya

Air: 0.175
Other: 0.175

79.2

36.3

44.5

4.95

90.2/75.5

41.3/34.6

50.7/42.5

5.63/4.72

N.A. / 1.05

22. Garlic and Leek

Air: 2
Other: 2

809

371

455

50.6

921/771

422/354

518/434

57.6/48.2

N.A. / 10.7

23. Grapes

Air: 2.75
Other: 27.47

970
9688

445
4440

546
5449

60.6
605

1105/925
11,034/9237

506 / 424
5057/4233

621/520
6206/5196

69/57.8
690 / 577

N.A. / 12.8
N.A./128

104


-------


Dietary-based EECs (mg/kg of Food
Item)

Dose-based EECs (mg/kg-bw) for:
20 g Bird /15 g Mammal



1 1 Fruit/

Herbivores and Insectivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadleat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

26. Brussel Sprouts and
Dandelion

Air: 2.5
Other: 2.5

951

436

535

59.4

1083 / 907

496/416

609/510

67.7/56.7

N.A. / 12.6

27. Swiss Chard, Chervil,
Endive (Escarole), Lettuce,
Head Lettuce, Leaf Lettuce
(Black Seeded Simpson,
Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley,
Roquette (Arrugula), Salsify,
and Spinach

Air: 2
Other: 2

1003

460

564

62.7

1143 /957

524/438

643 /538

71.4/59.8

N.A. / 13.3

28. Peppermint

Air: 1
Other: 1

476

218

267

29.7

542/453

248/208

305/255

33.9/28.3

N.A. / 6.3

29. Eggplant

Air: 3.5
Other: 3.5

1720

788

967

107

1959 / 1640

898/752

1102/922

122 / 102

N.A. / 22.8

30. Pumpkin

Air: 2
Other: 2

895

410

503

55.9

1019/853

467/391

573 /480

63.7/53.3

N.A. / 11.9

31. Cucumber, Cucurbit
Vegetables, Melons -
Unspecified, Cantaloupe,
Honey dew, Musk, Water, and
Winter

(Casaba/Crenshaw/Honeydew
/Persian), and Squash (All Or
Unspecified)

Air: 1.875
Other: 1.875

839

385

472

52.4

956 / 800

438/367

538/450

59.7/50

N.A. / 11.1

32. Onion (Unspecified and
Green), Radish, and Shallot

Air: 2
Other: 2

809

371

455

50.6

921/771

422/354

518/434

57.6/48.2

N.A. / 10.7

33. Potato - White/Irish

Air: 3
Other: 3

1213

556

683

75.8

1382/ 1157

633 /530

777/651

86.4/72.3

N.A. / 16.1

34. Turnip

Air: 2.5
Other: 2.5

1011

463

569

63.2

1152/964

528/442

648 / 542

72/60.3

N.A. / 13.4

105


-------


Dietary-based EECs (mg/kg of Food
Item)

Dose-based EECs (mg/kg-bw) for:
20 g Bird /15 g Mammal



1 1 Fruit/

Herbivores and Insectivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadleat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

35. Parsnip and Rutabaga

Air: 2
Other: 2

809

371

455

50.6

921/771

422/354

518/434

57.6/48.2

N.A. / 10.7

36. Sweet Potato

Air: 1.875
Other: 1.875

636

292

358

39.8

725 / 607

332/278

408/341

45.3 /37.9

N.A./8.43

37. Bluegrass, Canarygrass,
Grass Forage/Fodder/Hay,
Pastures, Peas (Including
Vines), Rangeland,
Sudangrass, and Timothy

Air: 1.25
Other: 1.25

798

366

449

49.9

908 / 760

416/349

511/428

56.8/47.5

N.A. / 10.6

40. Beets, Cowpea/Blackeyed
Pea, and Peas (Unspecified
and Field)

Air: 2.5
Other: 2.5

1011

463

569

63.2

1152/964

528/442

648 / 542

72/60.3

N.A. / 13.4

41. Carrot (Including Tops),
Celtuce, Fennel, and Pepper

Air: 2
Other: 2

1014

465

571

63.4

1155/967

529/443

650 / 544

72.2/60.4

N.A. / 13.4

42. Beans, Beans - Dried-
Type, Beans - Succulent
(Lima), and Beans - Succulent
(Snap)

Air: 1.75
Other: 1.75

710

325

399

44.4

808 / 677

370/310

455/381

50.5/42.3

N.A. / 9.4

43. Celery

Air: 1.5
Other: 1.5

509

233

286

31.8

580/485

266 / 222

326/273

36.2/30.3

N.A. / 6.74

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

512

235

288

32

583 /488

267 / 224

328/274

36.4/30.5

N.A. / 6.78

45. Anise

Air: 0.9375
Other: 0.9375

383

176

215

23.9

436/365

200 / 167

245 / 205

27.3 /22.8

N.A. / 5.07

46. Strawberry

Air: 2
Other: 2

895

410

503

55.9

1019/853

467/391

573 /480

63.7/53.3

N.A. / 11.9

47. Sugar Beet

Air: 1.875
Other: 1.875

758

348

427

47.4

864 / 723

396 /331

486 / 407

54/45.2

N.A. / 10

48. Tomato

Air: 3.5

1720

788

967

107

1959 / 1640

898/752

1102/922

122 / 102

N.A. / 22.8

106


-------


Dietary-based EECs (mg/kg of Food
Item)

Dose-based EECs (mg/kg-bw) for:
20 g Bird /15 g Mammal



1 1 Fruit/

Herbivores and Insectivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadleat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds



Other: 3.5



















49. Okra

Air: 1.5
Other: 1.5

671

308

378

42

765 / 640

350/293

430/360

47.8/40

N.A. / 8.89

51. Sorghum

Air: 1.5
Other: 1.5

571

262

321

35.7

650/544

298/249

366 / 306

40.6 / 34

N.A./7.56

52. Barley, Cereal Grains,
Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

476

218

267

29.7

542/453

248/208

305/255

33.9/28.3

N.A. / 6.3

53. Gooseberry

Air: 16
Other: 16

6886

3156

3874

430

7843 / 6566

3595 /3009

4412/3693

490/410

N.A. / 91.2

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and
Raspberry (Black - Red)

Air: 4
Other: 4

1722

789

968

108

1961 /1641

899/752

1103 /923

123 / 103

N.A. / 22.8

55. Blueberry

Air: 2.5
Other: 2.5

1314

602

739

82.1

1496 / 1252

686 / 574

842 / 704

93.5/78.3

N.A. / 17.4

56. Caneberries and Currant

Air: 2
Other: 2

861

395

484

53.8

980/821

449/376

551/462

61.3/51.3

N.A. / 11.4

57. Passion Fruit (Granadilla)

Air: 0.75
Other: 0.75

338

155

190

21.2

385 /323

177 / 148

217/182

24.1/20.2

N.A. / 4.48

58. Mint and Spearmint

Air: 1
Other: 1

476

218

267

29.7

542/453

248/208

305/255

33.9/28.3

N.A. / 6.3

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

594

272

334

37.2

677 / 567

310/260

381/319

42.3 /35.4

N.A. / 7.87

61. Water Cress

Air: 2
Other: 2

983

450

553

61.4

1119/937

513/429

630 / 527

70/58.6

N.A. / 13

Non-agricultural Uses

Forestry. Christmas Tree
Plantations, Pine (Seed
Orchard), and Slash Pine
(Forest)

Air: 3.2
Other: 3.2

1048

480

589

65.5

1193 /999

547/458

671/562

74.6/62.4

N.A. / 13.9

107


-------


Dietary-based EECs (mg/kg of Food
Item)

Dose-based EECs (mg/kg-bw) for:
20 g Bird /15 g Mammal



1 1 Fruit/

Herbivores and Insectivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadleat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

Mosquito Control.

Intermittently Flooded
Areas/Water,

Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs
(without Human or Wildlife
Use), Polluted Water, and
Swamps/MarshesAV etlands/St
agnant Water

Air: 0.6
Other: 0.6

201

92

113

12.5

228/191

105 /87.7

129/108

14.3 / 12

N.A./2.66

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

1106

507

622

69.1

1260 / 1055

577/483

709 / 593

78.7/65.9

N.A. / 14.6

Public Health and Medfly
Control. Nonagricultural
Areas (Public Health Use),
Urban Areas, and Wide
Area/General Outdoor
Treatment (Public Health
Use)

Air: 0.6119
Other: 0.1361

251
55.7

115
25.5

141
31.3

15.7
3.48

285 /239
63.5 /53.1

131 / 109
29.1 /24.3

160/134
35.7/29.9

17.8/14.9
3.97/3.32

N.A./3.32
N.A. / 0.74

Residential.

Household/Domestic
Dwellings Outdoor Premises,
Ornamental and/or Shade
Trees, Ornamental
Herbaceous Plants,
Ornamental Lawns and Turf,
Ornamental Non-flowering
Plants, Ornamental Woody
Shrubs and Vines, and Urban
Areas

Other: 0.253

103

47.3

58

6.45

118/98.4

53.9 /45.1

66.1 /55.3

7.34/6.15

N.A. / 1.37

108


-------




Dietary-based EECs (mg/kg
Item)

of Food

Dose-based EECs (mg/kg-bw) for:
20 g Bird /15 g Mammal











Fruit/

Herbivores and Insectivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadlcat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

Rights-of-way.

Nonagricultural Rights-of-
way/Fencerows/Hedgerows
and Nonagricultural
Uncultivated Areas/Soils

Air: 0.9281
Other: 0.9281

304

139

171

19

346/290

159/133

195/163

21.6/18.1

N.A. / 4.02

Turf. Golf Course Turf
(Bermudagrass)

Air: 1.25
Other: 1.25

419

192

235

26.2

477/399

218/183

268 / 224

29.8/24.9

N.A./5.54

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

109


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EFED uses the T-Herps model to estimate the direct terrestrial effects to CRLF from
ingestion of chemical residues with food/prey items. Because the dose experienced by a
CRLF varies with its size, dose is estimated for a range of CRLF sizes: small (1.4 g),
medium (37 g), and large (238 g) CRLF (Table 18). Because small frogs are modeled to
have a higher metabolic rate than large CRLF, smaller frogs are estimated to receive a
higher dose than larger frogs when ingesting the same type of food item. However, it is
also assumed that small frogs are incapable of ingesting small herbivore mammals, small
insectivore mammals, and small terrestrial phase amphibians (note the "N. A." at the
small frog location within the last three columns of Table 18).

Because it is the small herbivore mammal food item that is estimated to have the highest
concentration and only the medium and large CRLF ingest this food item, it is the
medium CRLF (with their higher metabolic rate than the large CRLF) that receive the
highest doses. Dose based estimates for individual exposure scenarios vary from 0.99 to
394 mg/kg-bw for small frogs, 0.042 to 6320 mg/kg-bw for medium frogs, and 0.027 to
983 mg/kg-bw for large frogs.

110


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Table 18. Assessment of direct effects on California Red-legged Frog (CRLF) using dose-based estimated environmental concentrations (EECs) of
malathion based on the T-Herps model for small (1.4 g), medium (37 g), and large (238 g) CRLF.	



Maximum

Dose-based EECs (mg/kg-bw) for Small, Medium, and Large CRLF
(Small / Medium / Large)

Scenario Group. Crop/Silc

Application

Rates1
(Lbs. ai/A)

Broadlcaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Small Herbivore
Mammals

Small Inscctivorc
Mammals

Small Terrestrial
Phase
Amphibian

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine, Trefoil, and
Vetch

Air: 2
Other: 2

14.8/14.6/9.55

1.65/ 1.62/1.06

N.A. / 423 / 65.8

N.A. / 26.4/4.11

N.A./.51/.33

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

134/ 132/86.3

14.9/14.6/9.59

N.A. /3821 /594

N.A. / 239/37.1

N.A. / 4.57/2.99

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

111/109/71.4

12.3/12.1/7.93

N.A. / 3160/491

N.A. / 197/ 30.7

N.A. / 3.78/2.48

4. Chestnut

Air: 5
Other: 5

43.4/42.7/28.0

4.83 /4.74/3.11

N.A. / 1239/ 193

N.A./77.4/12.0

N.A. / 1.48/.97

5. Almond

Air: 1.25
Other: 4

11.1 / 10.9/7.14
35.5 /34.8/22.8

1.23/1.21/.79
3.94/3.87/2.54

N.A. / 316/49.1
N.A. /1011/157

N.A. / 19.7/ 3.07
N.A. / 63.2/ 9.83

N.A. / .38 / .25
N.A. / 1.21/.79

6. Date

Air: 1
Other: 2

6.30/6.19/4.06
12.6/12.4/8.11

.70 / .69 / .45
1.40/ 1.38/.90

N.A. / 180/27.9
N.A. / 359 /55.8

N.A. / 11.2/1.75
N.A. / 22.5/3.49

N.A./.21/.14
N.A. / .43 / .28

7. Filbert (Hazelnut)

Air: .625
Other: .625

5.54/5.44/3.57

.62 / .60 / .40

N.A. / 158/24.6

N.A. / 9.87/1.54

N.A./.19/.12

8. Avocado

Air: 9
Other: 9

69.4/68.2/44.7

7.71/7.57/4.96

N.A. / 1978/308

N.A. / 124/ 19.2

N.A. / 2.37/1.55

9. Citrus, Citrus Hybrids other than Tangelo,
Grapefruit, Kumquat, Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

222/218/ 143

24.6/24.2/ 15.9

N.A. / 6320/983

N.A./395/61.4

N.A. / 7.56/4.95

10. Amaranth - Chinese, Broccoli (Unspecified,
Chinese, and Raab), Cabbage (Unspecified and
Chinese), CanolaVRape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard Cabbage (Gai
Choy/Pak-Choi), and Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

22.3/21.9/14.3

2.47/2.43 / 1.59

N.A. / 635 /98.7

N.A. / 39.7/6.17

N.A. / .76 / .50

11. Corn (Unspecified, Field, Pop, and Sweet) and
Millet (Foxtail)

Air: 1.5
Other: 1.5

18.7/18.4/12.1

2.08/2.05 / 1.34

N.A. / 534 /83.1

N.A. / 33.4/5.19

N.A. / .64 / .42

111


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Maximum

Dose-based EECs (mg/kg-bw) for Small, Medium, and Large CRLF
(Small / Medium / Large)

Scenario Group. Crop/Silc

Application

Rates1
(Lbs. ai/A)

Broadlcaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Small Herbivore
Mammals

Small Inscctivore
Mammals

Small Terrestrial
Phase
Amphibian

12. Cotton

Air: 4
Other: 4

66.6/65.5/42.9

7.40/7.28/4.77

N.A. / 1901/ 295

N.A. / 119/ 18.5

N.A. / 2.27/1.49

15. Apricot

Air: 10
Other: 10

94.1 /92.4/60.6

10.5/10.3/6.73

N.A. / 2683 / 417

N.A. / 168/26.1

N.A. / 3.21/ 2.10

16. Nectarine and Peach

Air: 9
Other: 9

84.7/83.2/54.5

9.41/9.24/6.06

N.A. / 2415/375

N.A./151/23.5

N.A. / 2.89/1.89

17. Cherry

Air: 8
Other: 8

78.2/76.9/50.4

8.69/8.54/5.6

N.A. / 2232/347

N.A. / 139/21.7

N.A. / 2.67/1.75

18. Fig

Air: 2.5
Other: 2.5

23.8/23.4/ 15.3

2.65/2.60/1.70

N.A. / 679 / 106

N.A. / 42.5/6.60

N.A. /.81/.53

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

12.4/12.1/7.96
14.8/14.6/9.55

1.37/ 1.35 /.88
1.65/ 1.62/ 1.06

N.A. / 352/54.8
N.A. / 423 /65.7

N.A. / 22.0/3.42
N.A. / 26.4/4.11

N.A. / .42 / .28
N.A./.51/.33

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

7.41/7.29/4.78
14.8/14.6/9.55

.82/.81/.53
1.65/ 1.62/ 1.06

N.A. / 211 / 32.9
N.A. / 423 /65.7

N.A. / 13.2/2.05
N.A. / 26.4/4.11

N.A./.25/. 17
N.A./.51/.33

21. Papaya

Air: .175
Other: .175

1.73 / 1.70/ 1.11

.19/.19/.12

N.A. / 49.3/7.67

N.A. / 3.08/.48

N.A. / .06 / .04

22. Garlic and Leek

Air: 2
Other: 2

17.7/17.4/11.4

1.96/ 1.93 / 1.27

N.A. / 504/78.4

N.A. / 31.5/4.90

N.A. / .60 / .40

23. Grapes

Air: 2.75
Other: 27.47

21.2/20.8/13.7
212/208/ 136

2.36/2.31/1.52
23.5 /23.1 / 15.2

N.A. / 605 /94.0
N.A. / 6039/ 939

N.A. / 37.8/5.87
N.A. / 377/58.7

N.A. / .72 / .47
N.A. / 7.22/4.73

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

20.8/20.4/ 13.4

2.31/2.27/1.49

N.A. / 593 / 92.2

N.A. / 37.1/5.76

N.A./.71/.46

27. Swiss Chard, Chervil, Endive (Escarole),
Lettuce, Head Lettuce, Leaf Lettuce (Black
Seeded Simpson, Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley, Roquette (Arrugula),
Salsify, and Spinach

Air: 2
Other: 2

21.9/21.6/14.1

2.44/2.39/ 1.57

N.A. / 625 / 97.2

N.A. / 39.1/6.08

N.A. / .75 / .49

28. Peppermint

Air: 1
Other: 1

8.31/8.17/5.36

.92/.91/.60

N.A. / 237/36.9

N.A. / 14.8/ 2.3

N.A./.28/. 19

29. Eggplant

Air: 3.5
Other: 3.5

37.6/36.9/24.2

4.18/4.1/2.69

N.A. / 1072 / 167

N.A. / 67/10.4

N.A. / 1.28/.84

112


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Maximum

Dose-based EECs (mg/kg-bw) for Small, Medium, and Large CRLF
(Small / Medium / Large)

Scenario Group. Crop/Silc

Application

Rates1
(Lbs. ai/A)

Broadlcaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Small Herbivore
Mammals

Small Inscctivore
Mammals

Small Terrestrial
Phase
Amphibian

30. Pumpkin

Air: 2
Other: 2

19.6/19.2/12.6

2.17/2.14/1.4

N.A. / 558 / 86.7

N.A. / 34.9/5.42

N.A. / .67 / .44

31. Cucumber, Cucurbit Vegetables, Melons -
Unspecified, Cantaloupe, Honeydew, Musk,
Water, and Winter

(Casaba/Crenshaw/Honeydew/Persian), and
Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

18.3/18/11.8

2.04/2/1.31

N.A. / 523 / 81.3

N.A. / 32.7/5.08

N.A./.63/.41

32. Onion (Unspecified and Green), Radish, and
Shallot

Air: 2
Other: 2

17.7/17.4/11.4

1.96/ 1.93 / 1.27

N.A. / 504/78.4

N.A. / 31.5/4.90

N.A. / .60 / .40

33. Potato - White/Irish

Air: 3
Other: 3

26.5/26.1/ 17.1

2.95/2.90/ 1.90

N.A. /756/ 118

N.A. / 47.3/7.35

N.A./.90/.59

34. Turnip

Air: 2.5
Other: 2.5

22.1/21.7/14.2

2.46/2.41/1.58

N.A. / 630/98.0

N.A. / 39.4/6.12

N.A. / .75 / .49

35. Parsnip and Rutabaga

Air: 2
Other: 2

17.7/17.4/11.4

1.96/ 1.93 / 1.27

N.A. / 504/78.4

N.A. / 31.5/4.90

N.A. / .60 / .40

36. Sweet Potato

Air: 1.875
Other: 1.875

13.9/13.7/8.96

1.54/ 1.52/ 1.00

N.A. / 397/61.7

N.A. / 24.8/3.85

N.A./.47/.31

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas (Including
Vines), Rangeland, Sudangrass, and Timothy

Air: 1.25
Other: 1.25

17.4/17.1/11.2

1.94/ 1.90/1.25

N.A. / 497/77.3

N.A. / 31.1/4.83

N.A./.59/.39

40. Beets, Cowpea/Blackeyed Pea, and Peas
(Unspecified and Field)

Air: 2.5
Other: 2.5

22.1/21.7/14.2

2.46/2.41/1.58

N.A. / 630/98.0

N.A. / 39.4/6.12

N.A. / .75 / .49

41. Carrot (Including Tops), Celtuce, Fennel, and
Pepper

Air: 2
Other: 2

22.2/21.8/14.3

2.46/2.42/1.59

N.A. / 632/ 98.3

N.A. / 39.5/6.14

N.A. / .76 / .50

42. Beans, Beans - Dried-Type, Beans - Succulent
(Lima), and Beans - Succulent (Snap)

Air: 1.75
Other: 1.75

15.5/15.2/9.99

1.72/ 1.69/ 1.11

N.A. / 442/68.8

N.A. / 27.6/4.30

N.A./.53/.35

43. Celery

Air: 1.5
Other: 1.5

11.1/10.9/7.16

1.24/1.21/.80

N.A. / 317/49.3

N.A. / 19.8/3.08

N.A. / .38 / .25

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

11.2/11.0/7.20

1.24/ 1.22/.80

N.A. / 319/49.6

N.A. / 19.9/3.1

N.A. / .38 / .25

113


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Maximum

Dose-based EECs (mg/kg-bw) for Small, Medium, and Large CRLF
(Small / Medium / Large)

Scenario Group. Crop/Silc

Application

Rates1
(Lbs. ai/A)

Broadlcaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Small Herbivore
Mammals

Small Inscctivore
Mammals

Small Terrestrial
Phase
Amphibian

45. Anise

Air: .9375
Other: .9375

8.37/8.23 /5.39

.93/.91/.60

N.A. / 239/ 37.1

N.A. / 14.9/2.32

N.A./.29/. 19

46. Strawberry

Air: 2
Other: 2

19.6/19.2/12.6

2.17/2.14/1.40

N.A. / 558 / 86.7

N.A. / 34.9/5.42

N.A. / .67 / .44

47. Sugar Beet

Air: 1.875
Other: 1.875

16.6/16.3/10.7

1.84/1.81/1.19

N.A. / 473 /73.5

N.A. / 29.5/4.59

N.A./.57/.37

48. Tomato

Air: 3.5
Other: 3.5

37.6/36.9/24.2

4.18/4.10/2.69

N.A. / 1072 / 167

N.A./67.0/10.4

N.A. / 1.28/.84

49. Okra

Air: 1.5
Other: 1.5

14.7/14.4/9.45

1.63 / 1.60/ 1.05

N.A. / 418/ 65.1

N.A. / 26.2/4.07

N.A./.50/.33

51. Sorghum

Air: 1.5
Other: 1.5

12.5/12.3/8.03

1.39 / 1.36/.89

N.A. / 356 /55.3

N.A. / 22.2/3.46

N.A. / .43 / .28

52. Barley, Cereal Grains, Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

10.4/10.2/6.69

1.15/1.13/.74

N.A. / 296/46.1

N.A. / 18.5/2.88

N.A. / .35 / .23

53. Gooseberry

Air: 16
Other: 16

150/ 148/96.9

16.7/16.4/10.8

N.A. / 4292/667

N.A. / 268/41.7

N.A. / 5.13/3.36

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

37.6/37.0/24.2

4.18/4.11/2.69

N.A. / 1073 / 167

N.A./ 67.1/ 10.4

N.A. / 1.28/.84

55. Blueberry

Air: 2.5
Other: 2.5

28.7/28.2/ 18.5

3.19/3.13/2.05

N.A. / 819/ 127

N.A. / 51.2/7.96

N.A. / .98 / .64

56. Caneberries and Currant

Air: 2
Other: 2

18.8/18.5/12.1

2.09/2.05 / 1.35

N.A. / 537 / 83.4

N.A. / 33.5/5.21

N.A. / .64 / .42

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

7.40/7.27/4.76

.82/.81/.53

N.A. / 211 / 32.8

N.A. / 13.2/2.05

N.A./.25/. 17

58. Mint and Spearmint

Air: 1
Other: 1

8.31/8.17/5.36

.92/.91/.60

N.A. / 237/36.9

N.A. / 14.8/2.30

N.A./.28/. 19

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

13.0/12.8/8.37

1.44/ 1.42/.93

N.A. / 371 /57.6

N.A. / 23.2/ 3.60

N.A. / .44 / .29

61. Water Cress

Air: 2
Other: 2

21.5/21.1/13.8

2.39/2.35 / 1.54

N.A. / 613/95.2

N.A. / 38.3/5.95

N.A. / .73 / .48

114


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Maximum

Dose-based EECs (mg/kg-bw) for Small, Medium, and Large CRLF
(Small / Medium / Large)

Scenario Group. Crop/Site

Application

Rates1
(Lbs. ai/A)

Broadlcaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Small Herbivore
Mammals

Small Inscctivore
Mammals

Small Terrestrial
Phase
Amphibian

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine (Seed
Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

22.9/22.5/ 14.7

2.54/2.50/ 1.64

N.A. / 653 / 102

N.A. / 40.8/6.34

N.A./.78/.51

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs (with
Human or Wildlife Use), Lakes/Ponds/Reservoirs
(without Human or Wildlife Use), Polluted Water,
and Swamps/Marshes/Wetlands/Stagnant Water

Air: .6
Other: .6

4.38/4.31/2.82

.49/.48/.31

N.A. / 125/ 19.4

N.A. / 7.82/1.22

N.A. /. 15/. 10

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

24.2/23.8/ 15.6

2.69/2.64/1.73

N.A. /689/ 107

N.A. / 43.1/6.70

N.A. / .82 / .54

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use), Urban
Areas, and Wide Area/General Outdoor Treatment
(Public Health Use)

Air: .6119
Other: .1361

5.47/5.38 /3.53
1.22/ 1.20/.78

.61 / .60/.39
.14/.13/.09

N.A. / 156/24.3
N.A. / 34.7/5.40

N.A. / 9.76/1.52
N.A. /2.17/.34

N.A./.19/.12
N.A. / .04 / .03

Residential. Household/Domestic Dwellings
Outdoor Premises, Ornamental and/or Shade
Trees, Ornamental Herbaceous Plants, Ornamental
Lawns and Turf, Ornamental Non-flowering
Plants, Ornamental Woody Shrubs and Vines, and
Urban Areas

Other: ,253

2.25/2.22/ 1.45

.25 /.25/.16

N.A. / 64.3/ 10

N.A. / 4.02 / .62

N.A. / .08 / .05

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

6.64/6.53 /4.28

.74 / .73 / .48

N.A. / 189/29.4

N.A./II.8/1.84

N.A./.23/. 15

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

9.15/8.99/5.89

1.02/ 1.00/.65

N.A. / 261/40.6

N.A. / 16.3/2.53

N.A./.31/.20

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

115


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3.3.2 Terrestrial Plant Exposure Modeling

Malathion (and consequently, its degradates) is directly applied to wide variety of
terrestrial plant crops without apparently affecting these plants negatively. Therefore, it
seems unlikely that other terrestrial plants would be negatively impacted through non-
target or incidental exposure.

As a check on this assumption, the highest application rate assuming direct application
and no dissipation effects was compared to the lowest affect level found for terrestrial
plants (30 kg/cm2). Converting the highest application rate of 27.47 lbs. ai/A (the "other"
use application rate for grapes, scenario 23) to comparable units (kg/cm2) produces:

27.471bs./A x 1.12^^- x 106mg/kg

			lbsVA—		_ o.31mg/cm2

10000m /ha x 10000cm / m

Because the maximum exposure (0.31 mg/cm2) is much less than the lowest adverse
effect concentration, the assumption that malathion and its degradates are unlikely to
harm CRLF through an indirect effect on terrestrial plants seems justified. Therefore,
there will be no further analysis of exposure of terrestrial plants.

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4. Effects Assessment

This effects assessment identifies assessment endpoints that can be used to judge whether
the EECs developed in the exposure assessment (Section 3) for malathion and maloxon
would be likely to cause adverse effects to the CRLF and/or its habitat. Assessment
endpoints are expressed in concentration units measured over a time period and,
therefore, can be compared directly to EECs. Acute assessment endpoints are
concentrations that cause an adverse affect over a brief duration of exposure. Conversely,
chronic assessment endpoints are concentrations that cause an adverse affect over a
longer duration of exposure. These assessment endpoints will be compared to the peak
EECs (acute endpoints) and maximum average 21-day and 60-day EECs (chronic
endpoints) in the risk characterization section (Section 5) of this risk assessment.

As previously discussed in Section 2.7, selected assessment endpoints for the CRLF
include assessment of direct toxic effects on the survival, reproduction, and growth of the
frog itself, as well as indirect effects, such as reduction of the prey base and/or
modification of its habitat (Table 5). Taxa selected as measurement endpoints include
freshwater fish and amphibians as a prey item and also as a surrogate for aquatic phase
CRLF; freshwater aquatic invertebrates (prey item); birds as surrogates for terrestrial
phase CRLF and other amphibians (prey item); small mammals (prey item); terrestrial
invertebrates (prey item); aquatic plants, and terrestrial plants (Table 5). Toxicity data for
freshwater fish and birds are also used as surrogate data for aquatic-phase and terrestrial-
phase amphibians (USEPA 2004).

Information on the toxicity of malathion and its impurity/degradate, maloxon, to selected
taxa is characterized based on registrant-submitted studies and a comprehensive review
of the open literature on malathion and maloxon. Values used for each measurement
endpoint identified in Table 5 are selected from this data. Currently, no FIFRA data
requirements exist for aquatic-phase or terrestrial-phase frogs and are therefore not part
of typical registrant submitted data packages. However, some aquatic-phase frog survival
data for malathion are available from open literature (Table 19); these data were reviewed
for use in the risk determination.

4.1 Evaluation of Aquatic Ecotoxicity Studies

Toxicity measurement endpoints are selected from data from guideline studies submitted
by the registrant, and from open literature studies that meet the criteria for inclusion into
the ECOTOX database maintained by EPA/Office of Research and Development (ORD)
(USEPA 2004). Open literature data presented in this assessment were obtained from a
search of the ECOTOX database (June 2007). Additional information is provided in
Appendix B.

In order to be included in the ECOTOX database, papers must meet the following
minimum criteria:

1.	The toxic effects are related to single chemical exposure;

2.	The toxic effects are on an aquatic or terrestrial plant or animal species;

3.	There is a biological effect on live, whole organisms;

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4.	A concurrent environmental chemical concentration/dose or application rate is

reported; and

5.	There is an explicit duration of exposure.

Data that pass the ECOTOX screen are further evaluated for use in the assessment along
with the registrant-submitted data, and may be incorporated qualitatively or quantitatively
into this endangered species assessment. In general, effects data in the open literature,
matching measurement endpoints listed in Table 5, that are more conservative than the
registrant-submitted data and are found to be scientifically sound based on a review of the
paper are used quantitatively. In addition, effects data for taxa that are directly relevant to
the California Red-Legged Frog {i.e., aquatic-phase and terrestrial-phase amphibian data)
were also considered over the use of surrogate taxa effects data, if available. The degree
to which open literature data are used quantitatively or qualitatively is dependent on
whether the information is scientifically sound and whether it is quantitatively linked to
the assessment endpoints {e.g., maintenance of California Red-Legged Frog survival,
reproduction, and growth) identified in Section 2.7 (Table 5). For example, endpoints
such as behavior modifications are likely to be qualitatively evaluated, because
quantitative relationships between degree and type of behavior modifications and
reduction in species survival, reproduction, and/or growth are usually not available.

4.1.1 Acute Toxicity to Fish and Larval Stage Amphibians

Available laboratory acute toxicity data for freshwater fish and larval amphibians are
summarized in Table 1913. The data suggest that sensitivity to malathion is highly varied
ranging from 4 |ig/L to 45,000 |ig/L for fish and from 0.59 |ig/L to 19,200 |ig/L for larval
amphibians. In addition to the fish and larval amphibian studies listed above, there is an
immersion study involving leopard frogs (Ranapipiens). Adult frogs were immersed in
malathion (100% purity) treated water for 15 days. The LD50 for this study was
150,000 |ig/L (ECOTOX ref. 50823). Sublethal effects beyond the reproduction
endpoints commonly measured in chronic fish studies include growth, hematological,
immune function, acetyl cholinesterase inhibition, and protein and lipid metabolism
disruptions. In general, observations of these sublethal effects occurred at malathion
concentrations above selected acute and chronic endpoints for risk assessment.

13 Most of the tables in Section 4 of this assessment have formats similar to Table 19. The column labeled
"% ai" is the percentage of active ingredient (ai) to which the test organisms were exposed. The LC50 is the
concentration (extrapolated from the study data) at which 50% of the test organisms would die under the
conditions of the experiment. This list contains those endpoints available from submitted registrant data as
well as data available from the ECOTOX database. The registrant submitted data are referenced by unique
MRID (Master Record Identification) numbers that are assigned to studies submitted to U.S. EPA. The
ECOTOX data base listings are taken from those studies deemed acceptable for ECOTOX inclusion as well
as passing OPP data quality criteria. Studies are classified as core, supplemental, or unacceptable
depending on the study's suitability for developing an assessment endpoint. Core studies meet all of the
suitability criteria that OPP requires. Supplemental (Supl.) studies have minor deficiencies, but are deemed
useful for assessment endpoint identification. Unacceptable studies have deficiencies that preclude their use
and, therefore, are not included in the following tables. All studies evaluated, including unacceptable
studies, have full citations listed in Appendix B.

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Table 19. Freshwater fish and amphibian acute toxicity studies (sourced from OPP data and
ECOTOX studies meeting minimum quality for database and OPP).		

Species Tested

%
ai

LQo and Confidence
Limits (where available)
in jig/L

Reference
MRID or
ECOTOX

Classification

Freshwater Fish Effects

Bluegill sunfish

95

96 Hr LC5o=20
(16-25)

40098001

Core

Bluegill sunfish

95

96 Hr LC5o=30
(10-88)

40098001

Core

Bluegill sunfish

99

96 HrLC50=3 3 6.6

ECOTOX ref.
77525

Supl.

Red-ear sunfish

95

95 Hr LC50=62
(58-67)

40098001

Core

Rainbow trout

95

96 Hr LCS0=4*
(2-7)

40098001

Core

Rainbow trout

95

96 Hr LC50=160

ECOTOX ref.
12182

Supl.

Yellow perch

95

96 HrLC50=263
(205-338)

40098001

Core

Largemouth bass

95

96 HrLC50=250
(229-310)

40098001

Core

Carp

95

96 Hr LC50=6590
(4920-8820)

40098001

Supl.

Carp

--

96 Hr LC50=710

ECOTOX ref.
6999

Supl.

Carp

--

96 HrLC50=3150

ECOTOX ref.
69277

Supl.

Carp

95

96 Hr LC50=23180

ECOTOX ref.
14861

Supl.

Carp

57

96 Hr LC50=9462

ECOTOX ref.
89874

Supl.

Fathead minnow

95

96 HrLC50=8650
(6450-11500)

40098001

Core

Fathead minnow

--

96 Hr LC50= 12500

ECOTOX ref.
2155

Supl.

Fathead minnow

--

96 Hr LC50= 14100

ECOTOX ref.
12859

Supl.

Channel catfish

95

96 HrLC50=7620
(5820-9970)

40098001

Core

Coho salmon

95

96 HrLCso 170
(160-180)

40098001

Core

Cutthroat trout

95

96 HrLC50=174
(112-269)

40098001

Core

Brown trout

95

96 HrLC50=101
(84-115)

40098001

Core

Lake trout

95

96 Hr LC50=76
(47-123)

40098001

Core

Black bullhead catfish

95

96 HrLC50=11700
(9600-14100)

40098001

Core

Green sunfish

95

96 Hr LC50=1460
(900-2340)

40098001

Core

Walleye

95

96 Hr LC50=64
(59-70)

40098001

Core

119


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Species Tested

%
ai

LC5o and Confidence
Limits (where available)
in ji«/L

Reference
MRID or
ECOTOX

Classification

Tilapia

95

96 Hr LC50=2000

40098001

Core

Java tilapia

--

96 HrLC50=5880

ECOTOX ref.
166

Supl.

Mozambique tilapia

--

96 HrLC50=290.1

ECOTOX ref.
11603

Supl.

Nile tilapia

80

96 Hr LC50=140

ECOTOX ref.
3296

Supl.

Nile tilapia

98

96 HrLC50= 2200

ECOTOX ref.
20087

Supl.

Nile tilapia

57

96 Hr LC50= 1128.6

ECOTOX ref.
89874

Supl.

Goldfish

95

96 Hr LC5o= 10700
(8340-13800)

40098001

Core

Goldfish

NR

96 Hr LC50=2610

ECOTOX ref.
563

Supl.

Goldfish

95

96 Hr LC50=8490

ECOTOX ref.
13456

Supl.

Medaka

50

96 Hr LC50=2800

ECOTOX ref.
8977

Supl.

Medaka

99.1

96 Hr LC50= 9700

ECOTOX ref.
89099

Supl.

Killifish

--

24 HrLC50=28900

ECOTOX ref.
20487

Supl.

Pale chub

50

96 Hr LC50=9700

ECOTOX ref.
8977

Supl.

Western mosquitofish

--

24 Hr LC50=150

ECOTOX ref.
184

Supl.

Western mosquitofish

--

96 Hr LC50=200

ECOTOX ref.
5806

Supl.

Western mosquitofish

--

96 Hr LC50=300

ECOTOX ref.
20475

Supl.

Chinook salmon

--

96 Hr LC50=23

ECOTOX ref.
522

Supl.

Chinook salmon

--

96 HrLC50=120

ECOTOX ref.
2159

Supl.

Two spot barb

--

96 Hr LC50=1650

ECOTOX ref.
765

Supl.

Two spot barb

--

96 Hr LC50=3700

ECOTOX ref.
6722

Supl.

Two spot barb

~

96 Hr LC50=3200

ECOTOX ref.
9276

Supl.

Flagfish

~

96 HrLC50= 3 49

ECOTOX ref.
995

Supl.

Flagfish

~

48 HrLC50= 280

ECOTOX ref.
10687

Supl.

Asiatic knifefish

~

96 Hr LC50= 77

ECOTOX ref.
4022

Supl.

Indian catfish

--

96 Hr LC50= 45000

ECOTOX ref.
5064

Supl.

Indian catfish

100

96 Hr LC50= 15000

ECOTOX ref.
7375

Supl.

120


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Species Tested

%
ai

LQo and Confidence
Limits (where available)
in ji«/L

Reference
MRID or
ECOTOX

Classification

Indian catfish

--

96 Hr LC50= 15000

ECOTOX ref.
15179

Supl.

Indian catfish

--

96 HrLC50= 8500

ECOTOX ref.
17539

Supl.

Smooth-breasted
snakefish

—

96 Hr LC50= 6995

ECOTOX
ref.5736

Supl.

Cyprinion watsoni
no common name

57

24 Hr LC50= 7930

ECOTOX
ref.6638

Supl.

Hawk fish

--

96 HrLC50= 2250

ECOTOX ref.
9277

Supl.

Hawk fish

--

96 HrLC50= 5 3 97

ECOTOX ref.
12910

Supl.

Hawk fish

50

96 Hr LC50= 9360

ECOTOX ref.
14166

Supl.

Catla

--

72 HrLC50= 23 50

ECOTOX ref.
9277

Supl.

Rohu

--

96 Hr LC50= 4980

ECOTOX ref.
9277

Supl.

Slender rasbora

--

96 HrLC50= 6000

ECOTOX ref.
10764

Supl.

Tic tac toe barb

--

96 HrLC50= 4000

ECOTOX ref.
10764

Supl.

Striped bass
(freshwater)

—

96 HrLC50= 24.5

ECOTOX ref.
11334

Supl.

Striped bass
(freshwater)

—

96 Hr LC50= 12

ECOTOX ref.
15472

Supl.

Snakehead catfish

--

96 HrLC50= 3 8 90

ECOTOX ref.
11988

Supl.

Snakehead catfish

100

96 HrLC50= 894

ECOTOX ref.
14166

Supl.

Snakehead catfish

"

96 HrLC50= 874

ECOTOX ref.
14166

Supl.

Snakehead catfish

~

96 HrLC50= 6610

ECOTOX ref.
81095

Supl.

Zebra danio

~

96 Hr LC50= 155

ECOTOX ref.
12047

Supl.

Bitterling

95

96 Hr LC50= 4807

ECOTOX ref.
12047

Supl.

Bleak

95

96 HrLC50= 3 5 91

ECOTOX ref.
12047

Supl.

Crimson-spotted
rainbowfish

—

96 Hr LC50= 2090

ECOTOX ref.
15030

Supl.

Atlantic salmon

98

96 HrLC50= 313.6

ECOTOX ref.
16946

Supl.

Loach

100

96 Hr LC50= 13790

ECOTOX ref.
17207

Supl.

Giant gourami

99

96 Hr LC50= 1480

ECOTOX ref.
74220

Supl.

Climbing perch

100

96 Hr LC50= 16000

ECOTOX ref.
88437

Supl.

121


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Species Tested

%
ai

LQo and Confidence
Limits (where available)
in jig/L

Reference
M.RI.D or
ECOTOX

Classification

Amphibian Effects

Fowlers toad

technical

96 Hr LC50=420
(90-980)

ECOTOX ref.
2891

Supl.

Chorus frog

technical

96 Hr LC50=200
(90-270)

ECOTOX ref.
2891

Supl.

Indian bullfrog, six-
fingered frog

50

96 Hr LCso=0.59*
(0.43-0.78)

ECOTOX ref.
11521

Supl.

Tiger frog, Indian
bullfrog

100

148 Hr LC50=170

ECOTOX ref.
61878

Supl.

Argentine toad

NR

96 HrLC50= 19200
(N.R.)

ECOTOX ref.
3883

Supl.

Woodhouse toad

technical

96 Hr LC50=420

ECOTOX ref
344

Supl.

Western chorus frog

technical

48 Hr LC50=320

ECOTOX ref
2891

Supl.

Bog frog

--

48 HrLC50=2271

ECOTOX ref.
16056

Supl.

African clawed frog

>90

96 HrLC50= 98 1 0

ECOTOX ref.
66506

Supl.

Yellow-legged frog

--

96 HrLC50=2137

**

Supl.

*Endpoint used for quantitative assessment of risks.

** Sparling, D.W. and G. Fellers. 2006 Comparative toxicity of chlorpyrifos, diazinon, malathion and their
oxon derivatives to larval Rana boylii. Environmental Pollution (Article in Press; available online at
www, sciencedirect. coin).

The lowest larval amphibian acute endpoint is 0.59 |ig/L. The lowest fish acute toxicity
value is 4 |ig/L. These endpoints will be used for risk quotient calculation for direct
effects on aquatic phases of the frog and effects on fish prey source, respectively.

4.1.2 Freshwater Fish and Amphibian: Chronic Exposure
(Growth/Reproduction) Studies

Table 20 summarizes the available chronic exposure freshwater fish and other aquatic
vertebrate studies. There are paired species acute and chronic reproduction (NOAEC)
values for rainbow trout and flagfish. However, the NOAEC values established for
rainbow trout is higher than the most sensitive rainbow trout acute value, invalidating the
calculation of an acute to chronic ratio for this species as per OPP policy. For flagfish, the
largest acute to chronic ratio is 40.6 (349/8.6 = 40.6). Applying this value to the lowest
available freshwater fish acute toxicity value of 4 |ig/L yields a chronic effects endpoint
for freshwater fish of 0.098 |ig/L for use in risk quotient calculations. Applying the same
ACR to the lowest acute aquatic phase amphibian endpoint of 0.59 jig/L yields a
chronic amphibian effects endpoint of 0.014 jig/L for use in risk quotient
calculations.

122


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Table 20. Freshwater fish and other aquatic vertebrate chronic exposure toxicity data (growth,
survival, and reproduction endpoints) (sourced from OPP data and ECOTOX studies meeting
minimum quality for database and OPP). 			i	

Species

%
ai

Duration

(Days)

LOAEC

(Hg/L)

NOAEC
(Hg/L)

Reference MRID
or ECOTOX

Category

Rainbow trout

94

97

44

21

41422401

Core

Flagfish

tech

110

11

8.6

Hermanutz, R.,
1978*

Supl.

Fathead minnow

tech

158

350

N.D.

D234663

Supl.

Snakehead catfish

100

15

-

500

ECOTOX ref.
14673

Supl.

Medaka

99.8

14

798.4

199.6

ECOTOX ref.
59285

Supl.

Nile tilapia

100

168

500

-

ECOTOX ref.
92183

Supl.

* Hermanutz, R. 1978. Endrin and Malathion toxicity to Flagfish (Jordanella floridae). Arch. Of
Environmental Contaminants and Toxicology 7:159-168, as cited in malathion RED.

4.1.3 Freshwater Fish: Sublethal Effects and Additional Open Literature
Information

Table 21 presents available sublethal endpoints for freshwater fish and other aquatic
vertebrates. EFED has no information for establishing quantitative relationships of these
sublethal endpoints with the assessment endpoints, precluding the use of these endpoints
in the calculation of RQ values. However, it is important to note that in all cases, none of
the above NOAEC or LOAEC values falls below acute and chronic endpoints used to
calculate RQ values in this risk assessment.

Table 21. Freshwater fish and other aquatic vertebrate sublethal effects (sourced from OPP data and

Species

%
ai

Duration

(Days)

Effect Type

LOAEC

(Hg/l)

NOAEC
(Hg/L)

Reference
MRID or
ECOTOX

Category

Zambezi barbel

98

5

growth, edema

1225

617.4

ECOTOX ref.
65919

Supl.

Zambezi barbel

98

5

growth

2450

1225

ECOTOX ref.
88998

Supl.

Mozambique tilapia

95

2

biochemical and
enzymatic

2000

-

ECOTOX ref.
12190

Supl.

Mozambique tilapia

100

2

biochemical and
cellular

2000

-

ECOTOX ref.
13476

Supl.

Mozambique tilapia

100

2

cellular

690

-

ECOTOX ref.
13920

Supl.

Goldfish

85

3

behavioral

1000

500

ECOTOX ref.
13456

Supl.

Channel catfish

100

20

acetyl

cholinesterase
inhibition

IC50=180
0

-

ECOTOX ref.
14034

Supl.

123


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Species

%
ai

Duration

(Days)

Effect Type

LOAEC

(Hg/1)

NOAEC
(Hg/L)

Reference
MRID or
ECOTOX

Category

Channel catfish

56.1

30

humoral immune
response

1750

500

ECOTOX ref.
89134

Supl.

Snake-head catfish

100

15

hematological

250

--

ECOTOX ref.
14673

Supl.

Snake-head catfish

100

15

In vitro lipid and
protein synthesis
markers

290

140

ECOTOX ref.
88911

Supl.

Walking catfish

100

30

cytochrome a
activity

1000

--

ECOTOX ref.
15861

Supl.

Walking catfish

100

7

protein content

40

--

ECOTOX ref.
72761

Supl.

Walking catfish

100

120

acetyl

cholinesterase
inhibition

190

--

ECOTOX ref.
89006

Supl.

Walking catfish

100

4-16

thyroid function
markers

3.5-7

--

ECOTOX ref.
89093

Supl.

Medaka

99.8

15

hematological
and

immunological

199.6

--

ECOTOX ref.
59285

Supl.

Gilthead seabream

100

7

chromosomal
aberrations

--

6380

ECOTOX ref.
60863

Supl.

Carp

100

0.0417

acetyl

cholinesterase
inhibition

30,000

--

ECOTOX ref.
64529

Supl.

Carp

100

7

lipid metabolism

biochemical

markers

100

--

ECOTOX ref.
72824

Supl.

Rainbow trout

>98

1

behavioral

20

--

ECOTOX ref.
65887

Supl.

Giant gourami

99

1

biochemical

1000

--

ECOTOX ref.
74220

Supl.

Catla

50

15

protein

metabolism

markers

1000

--

ECOTOX ref.
82785

Supl.

Brook trout

95

10

cough response

6.9

--

ECOTOX ref.
86858

Supl.

Zebra danio

95

7

nucleotide
hydrolysis
markers

475

47.5

ECOTOX ref.
88999

Supl.

4.1.4 Freshwater Invertebrates: Acute Exposure Studies

Table 22 presents the available acute exposure toxicity studies for freshwater
invertebrates. As for the case with fish and amphibians, malathion sensitivity is highly
varied with acute endpoints ranging from 0.01 |ig/L to 67,750 |ig/L. The lowest
freshwater invertebrate acute exposure endpoint available from Table 22 is for an

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LC5o of 0.01 jig/L. This endpoint will be used to calculate freshwater invertebrate
acute risk quotients.

Table 22. Freshwater invertebrate acute toxicity studies (sourced from OPP data and ECOTOX
studies meeting minimum quality for database and OPP).			

Species Tested

%
ai

Du ration
(Hours)

EC si, or LQo in Jig/L

Reference
MRID or
ECOTOX

Classification

Calanoid copepod,

Diaptomus sp.

-

48

2

ECOTOX ref.
786

Supl.

Cyclopoid copepod,

Eucyclops sp.

-

48

1

ECOTOX ref.
786

Supl.

Ostracod, Cypria sp.

-

48

2

ECOTOX ref.
786

Supl.

Ostracod, Cypretta
kawatai

-

72

86

ECOTOX ref.
7796

Supl.

Daphnid Simocephalus
serrulatus

95

48

0.69
(0.44-0.79)

40098001

Supl.

Water flea, Daphnia
magna

95

48

1.0
(0.7-1.4)

40098001

Core

Water flea, Daphnia
magna

57

48

2.2
(1.9-2.5)

41029701

Core

Water flea, Daphnia
magna

-

24

0.098

ECOTOX ref.
5539

Supl.

Water flea, Daphnia
magna

-

48

1.7

ECOTOX ref.
6449

Supl.

Water flea, Daphnia
magna

-

24

2.35

ECOTOX ref.
20475

Supl.

Water flea, Alonella sp.

-

48

2

ECOTOX ref.
786

Supl.

Water flea, Daphnia pulex

95

48

1.8
(1.4-2.4)

40098001

Core

Water flea, Daphnia
carinata

-

48

100

ECOTOX ref.
5194

Supl.

Water flea, moina
macrocopa

--

132

0.01*

ECOTOX
ref. 16371

Supl.

Scud, Gammarus fasciatus

95

96

0.5
(N.R.)

40098001

Core

Scud, Gammarus fasciatus

-

48

Two assays 2and 0.5

ECOTOX ref.
887

Supl.

Scud, Gammarus lacustris

tech

48

1.8
(1.3-2.4)

05009242

Core

Scud, Gammarus lacustris

-

96

1.62

ECOTOX ref.
528

Supl.

Glass shrimp,

Palaemonetes kadiakensis

95

96

12
(N.R.)

40098001

Supl.

Glass shrimp,

Palaemonetes kadiakensis

-

48

Two assays 25 and 100

ECOTOX ref.
887

Supl.

Shrimp, Paratya
compressa

-

96

3.62

ECOTOX ref.
18945

Supl.

Seed Shrimp, Cypridopsis
vidua

95

48

47
(32-69)

40098001

Core

Prawn, Macrobrachium
lamarrei

-

48

1261

ECOTOX ref.
11557

Supl.

125


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Species Tested

%
ai

Du ration
(Hours)

EC J,, or LQo in jijj/L

Reference
MRID or
ECOTOX

Classification

Fairy shrimp,
Streptocephalus sudanicus

100

48

67750

ECOTOX ref.
59962

Supl.

Crayfish,Orconectes nais

95

96

180
(140-230)

40098001

Supl.

Red swamp crayfish,

Procambrus clarkii

-

96

1340

ECOTOX ref.
20475

Supl.

Crab, Paratelphusa
hydrodromus

-

96

6000

ECOTOX ref.
13437

Supl.

Sowbug, Asellus
brevicaudus

95

96

3000
(1500-8500)

40098001

Supl.

Dragonfly Orthetrum
albistylum

-

48

730

ECOTOX
ref.7119

Supl.

Dragonfly Odonata

50

24

220

ECOTOX
ref.45081

Supl.

Stonefly, Claasenia
sabulosa

95

49

2.8
(1.4-4.3)

40098001

Supl.

Stonefly, Pteronarcella
badia

95

48

1.1
(0.78-1.5)

40098001

Supl.

Stonefly, Isoperla sp.

95

48

0.69
(0.2-2.4)

40098001

Supl.

Stonefly, Hesperoperla
pacifica

-

96

7

ECOTOX ref.
528

Supl.

Stonefly, Hesperoperla
pacifica

-

48

12

ECOTOX ref.
2667

Supl.

Stonefly, Pteronarcys
californicus

-

96

50

ECOTOX ref.
528

Supl.

Stonefly, Pteronarcys
californicus

-

48

180

ECOTOX ref.
2667

Supl.

Damselfly, Lestes
congener

95

48

10

(6.5-15.0)

40098001

Supl.

Damselfly, Lestes
congener

-

24

300

ECOTOX ref.
7775

Supl.

Damselfly, Agriocnemis
sp.

50

24

300

ECOTOX ref.
45081

Supl.

Damselfly, Ceriagrion sp.

50

24

200

ECOTOX ref.
45081

Supl.

Caddisfly, Hydropsyche
sp.

95

48

5.0
(2.9-8.6)

40098001

Supl.

Caddisfly, Hydropsyche
sp.

-

24

12.3

ECOTOX ref.
2158

Supl.

Caddisfly, Limnephalus
sp.

95

48

1.3
(0.77-2.0)

40098001

Supl.

Caddisfly, Hydropsyche
californica

-

96

32

ECOTOX ref.
528

Supl.

Caddisfly, Arctopsyche
grandis

-

96

22.5

ECOTOX ref.
528

Supl.

Mayfly, Drunella grandis

-

96

100

ECOTOX ref.
528

Supl.

Mayfly, Hexagenia sp.

-

24

631

ECOTOX ref.
2158

Supl.

Mayfly, Cloeon sp

-

24

5.5

ECOTOX ref.
20475

Supl.

126


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Species Tested

%
ai

Du ration
(Hours)

EC J,, or LQo in jijj/L

Reference
MRID or
ECOTOX

Classification

Snipefly, Atherix
variegata

95

48

385
(245-602)

40098001

Supl.

Midge, Chironomidae

-

24

37.63

ECOTOX ref.
7954

Supl.

Midge, Chironomus sp.

-

24

2.1

ECOTOX ref.
2899

Supl.

Midge, Chironomus
tentans

-

24

2

ECOTOX ref.
6267

Supl.

Midge, Chironomus
tentans

-

72

2500

ECOTOX ref.
7796

Supl.

Midge, Chironomus
tepperi

-

24

8.4

ECOTOX ref.
13398

Supl.

Midge, Dicrotendipes
californicus

-

24

80

ECOTOX ref.
3671

Supl.

Midge, Cricotopus sp.

-

24

30

ECOTOX ref.
3671

Supl

Midge, Chironomus
decorus

-

24

70

ECOTOX ref.
3671

Supl

Midge, Chironomus
decorus

-

24

32

ECOTOX ref.
5559

Supl

Midge, Chironomus
crassicaudatuss

-

24

56

ECOTOX ref.
5559

Supl

Midge, Chironomus
riparius

-

24

1.9

ECOTOX ref.
6830

Supl

Midge, Chironomus
riparius

-

24

440

ECOTOX ref.
14897

Supl

Midge, tanytarsus sp.

-

24

32

ECOTOX ref.
5559

Supl

Midge, Glyptotendipes
paripes

-

24

4

ECOTOX ref.
5559

Supl

Midge, Goeldichironomus
holoprasinus

-

24

28

ECOTOX ref.
5559

Supl

Mosquito, Anopheles
freeborni

-

24

79

ECOTOX ref.

3660

Supl.

Mosquito, Anopheles
albimanus

-

24

350

ECOTOX ref.
11596

Supl.

Mosquito, Anopheles
stephensi

-

24

180

ECOTOX ref.
11799

Supl.

Mosquito, Anopheles
stephensi

100

24

633

ECOTOX ref.
59254

Supl.

Mosquito, Anopheles
gambiae

-

24

51.8

ECOTOX ref.
11799

Supl.

Mosquito, Anopheles
quadrimaculatus

-

48

1

ECOTOX ref.
56989

Supl.

Mosquito, Toxorhynchites
splendens

-

48

49.8

ECOTOX ref.
4139

Supl.

127


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Species Tested

%
ai

Du ration
(Hours)

EC J,, or LQo in jijj/L

Reference
MRID or
ECOTOX

Classification

Mosquito, Toxorhynchites
splendens

100

24

220

ECOTOX ref.
59254

Supl.

Mosquito, Aedes
nigromaculis

-

24

68

ECOTOX ref.
4431

Supl.

Mosquito, Aedes
trivittatus

-

24

32.2

ECOTOX ref.
4896

Supl.

Mosquito, Aedes aegypti

-

24

92

ECOTOX ref.
11009

Supl.

Mosquito, Aedes aegypti

100

24

23.2

ECOTOX
ref. 59254

Supl.

Mosquito, Aedes caspius

-

24

2230

ECOTOX ref.
13544

Supl.

Mosquito, Aedes
albopictus

-

24

379

ECOTOX ref.
16077

Supl.

Mosquito, Aedes
hendersoni

-

24

66

ECOTOX ref.
19944

Supl.

Mosquito, Aedes
triseriatus

-

24

43

ECOTOX ref.
19944

Supl.

Mosquito, Culex pipiens

-

24

42.6

ECOTOX ref.
4896

Supl.

Mosquito, Culex pipiens

35

72

50

ECOTOX ref.
4896

Supl.

Mosquito, Culex pipiens

30

48

24

ECOTOX ref.
4896

Supl.

Mosquito, Culex pipiens

-

24

42.1

ECOTOX
ref. 12072

Supl.

Mosquito, Culex
quinquefasciatus

-

24

62.1

ECOTOX
ref. 12072

Supl.

Mosquito, Culex
quinquefasciatus

100

24

62.1

ECOTOX
ref. 59254

Supl.

Mosquito, Culex fatigans

100

24

440

ECOTOX
ref. 61960

Supl.

Mosquito, Culoseta
longiareolata

-

24

170

ECOTOX ref.
20475

Supl.

Beetle Eretes sticticus

-

48

430

ECOTOX ref.
5182

Supl.

Beetle, Peltodytes sp.

-

48

1500

ECOTOX ref.
7775

Supl.

Backswimmer, Notonecta
undulata

-

48

110

ECOTOX ref.
7775

Supl.

Backswimmer, Anisops
sardeus

100

48

42.2

ECOTOX ref.
59962

Supl.

*Endpoint used for quantitative assessment of risks.

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4.1.5 Freshwater Invertebrates: Chronic Exposure Studies

Table 23 presents available chronic exposure effects endpoints for freshwater
invertebrates. There are limited chronic effects studies and with limited opportunities to
compare acute and chronic endpoints within species. Because Daphnia magna is not the
most sensitive species tested acutely, a chronic endpoint for risk quotient calculation
was derived by applying the largest freshwater invertebrate acute to chronic ratio
for the daphnid (LC50 2.35/NOEC 0.006 = 392) to the most sensitive invertebrate
acute endpoint to result in a chronic effects endpoint of 0.000026 jig/L (0.01/392 =
0.000026).

Table 23. Freshwater invertebrate chronic exposure toxicity studies (sourced from OPP data and
ECOTOX studies meeting minimum quality for database and OPP).			

Species 1 esled

O.'

.'O

ai

Duration
(l);i\s)

NOI-'.(71.OI-'.C (Ug/I.)

Reference
MRU) or
I'.COTOX

Classificalion

Water flea, Daphnia
magna

94

21

0.006/0.1

41718401

Core

Water flea, Daphnia
magna

-

21

0.15/not reported

ECOTOX ref.
6449

Supl.

4.1.6 Toxicity to Aquatic Plants

Table 24 summarizes available aquatic plant effects data from both registrant submitted
and ECOTOX database holdings passing ECOTOX and OPP data quality criteria. For
unicellular aquatic plants the lowest pair of EC50 and NOEC is 2040 and 500 jig/L.
For vascular plants, there is no established EC50, but the NOEC is 24,065 jig/L.
These values will be used for risk quotient calculation.

Table 24. Aquatic plant toxicity studies (sourced from OPP data and ECOTOX studies meeting
minimum quality for database and OPP)				

Species Tested

%
ai

Du ration

(Days)

ECSo/NOEC or EQ
(Hg/L)

Reference
MRID or
ECOTOX

Classification

Blue-green algae

Anabaena flosaquae

60

6

129,080/92,940

ECOTOX ref.
61937

Supl.

Blue-green algae Nostoc
calcicola

100

6

No ECso/200,000

ECOTOX ref.
61937

Supl.

Green algae Scenedesmus
obstusiusculus

60

6

33,228/22,392

ECOTOX ref.
61937

Supl.

Green algae dunaliella
tertiolecta

--

1

17,880/no NOEC

ECOTOX
ref.66270

Supl.

Green algae

Pseudokirchneriella

subcapitata

100

2

2040/500*

ECOTOX
ref. 85816

Supl.

Large duckweed
Spirodela polyrhiza

96.26

7

No ECSo/24065*

ECOTOX
ref. 9184

Supl.

*Endpoint used for quantitative assessment of risks.

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4.2 Evaluation of Terrestrial Ecotoxicity Studies

4.2.1 Toxicity to Mammals

A variety of mammalian acute toxicity values are available from the Agency's Health
Effects Division (HED) and form the basis for a wild mammal effects profile. In addition
to the laboratory studies, data exist demonstrating malathion effects on small mammal
populations in the field at an application rate of 2 lb/acre.

4.2.1.1 Acute and Chronic Mammalian Toxicity

Table 25 presents the available HED acute and reproduction endpoints used in the risk
assessment. The rat LD50 of 3400 will serve as the acute mammalian effects endpoint
for risk quotient calculations. The rat 240 mg/kg/day reproduction effect for
reduced pup survival will be used to calculate chronic mammalian risk quotients.

Table 25. Mammalian acute oral and chronic dietary toxicity studies.

Species

%ai

LDS0
(m«/K«)

Studv ID

NOEL (parameter)

Studv ID and Author

Category

Mice

-

-

-

500 mg/kg-diet (growth
-2 yr. chronic study)

Reference Doc#000389
N.C.I.,1979

N.R.

Rat

(Wistar
albino)

57%
EL

1763

Doc #000317

ataxia, tremors,
salivation, diarrhea
observed

Reference Doc#000317
Doc# 000389

Supl.

Rat

Tech

3400*

Doc #057701

MRID

00159876

1000 mg/kg-diet
(growth)

32 day ChE reduction
at 100 mg/kg-diet
240 mg/kg/day reduced
pup survival and BW

Reference Doc#000389
Karlow and Martin ,1965

N.R.

* Endpoint selected with consultation with the health Effects Division (August 2007).

4.2.1.2 Mammalian Field Studies

Giles and Robert (1970, as cited in the RED), investigated aerial application of malathion
to Ohio watersheds with one treated and the other untreated. Malathion was radio tagged
with Sulfur 35 radio nuclide. Application rate was 2 lbs/acre and 4 applications were
made. Species of small mammals (white-footed mice and chipmunks) showed significant
population reductions on treatment areas as compared with controls. Larger mammals
and interestingly, shrews which are often sensitive due to high metabolism, were not
observed to have been affected. Population reductions were not observed to be related to
acute adult mortality, but rather to reduced reproductive success or possibly effects on
survival of young. While this study does not provide endpoints for direct incorporation
into risk quotient calculations, it affirms that utilization of reproduction endpoints in the
chronic risk quotient calculations is meaningful in the context of evaluating potential
effects on mammalian populations. Also importantly the field study establishes that small

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mammals, like those of a size potentially consumed by the listed frog, are likely to be
sensitive organisms.

4.2.2 Toxicity to Birds

Effects data for birds span acute and reproduction studies in a variety of species and also
includes studies of malathion effects on avian embryo development enzyme activities and
liver function. Some of the developmental and sublethal effects studies involved exposure
routes not applicable to field situations or not represented by existing exposure estimation
methods in Agency risk assessment precluding quantitative use in the risk assessment
process. When exposure routes were comparable to other lab studies and risk assessment
exposure estimation methods, the sublethal endpoints were adequately addressed by the
selection of acute and reproduction endpoints. Available field study data demonstrate that
malathion produces varying responses in birds under field application scenarios and seem
to indicate that reliance of acute and reproduction laboratory studies may be conservative
for assessing avian risk with this pesticide.

4.2.2.1 Acute and Subacute Avian Toxicity

Results of avian oral acute tests with malathion are tabulated in Table 26. The most
sensitive species tested was the ring-necked pheasant, and this endpoint will be used
for any quantitative risk estimations.

Table 26. Avian acute oral toxicity studies (sourced from OPP data and ECOTOX studies meeting
minimum quality for database and OPP). 		

Species

%
ai

LD5„ (mg/kg-bw)
(CL's, when
available)

MRID or ECOTOX

Classification

Mallard duck

95

14D LD50=1485
(1020-2150)

00160000

Core

Ring-necked
pheasant

95

14D LDS0=167*
(120-231)

00160000

Supl.

Horned lark

95

14D LD50=403
(247-658)

00160000

Supl.

Sharp tailed
grouse

tech

LD50 =220
(171-240)

Crabtree, D.G., 1965, Denver Wildlife
Res. Center, USFWS as cited in RED

Supl.

Bantam chicken

97.7

LD5o = 524.8

ECOTOX ref. 36916

Supl.

*Endpoint used for quantitative assessment of risks.

Results of subacute dietary tests with malathion conducted by USFWS laboratories are
tabulated in Table 27. The lowest subacute dietary LC50 is 2128 mg/kg-diet.

Table 27. Avian Subacute Dietary Toxicity Studies (Sourced from OPP data and ECOTOX Studies
Meeting Minimum Quality for Database and OPP).			



%

LC50 (mg/kg-dict)

MRID or



Species

ai

(CL's, when available)

ECOTOOX

Classification

Ring-necked pheasant

95

8D LC50=2639
(2220-3098)

00022923

Core

Bobwhite quail

95

8D LC5o=3497
(2959-4011)

00022923

Core

131


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Species

%
ai

LC;o (mg/kg-diet)
(CL's, when available)

INI RID or

ECOTOOX

Classification

Japanese quail

95

8D LC50=2962
(2453-3656)

00022923

Supl.

Japanese quail

100

8D LCS0=2128*

ECOTOX ref.
35214

Supl.

Japanese quail

95

8D LC50=2968

ECOTOX ref.
50181

Supl.

Mallard duck

95

8D LC5o>5000

00022923

Core

*Endpoint used for quantitative assessment of risks.

4.2.2.2 Chronic Avian Toxicity

Available avian reproduction laboratory study results are tabulated in Table 28. Chronic
exposure to malathion in diets produced moderate toxicity to terrestrial avian species and
low toxicity to waterfowl species tested to date. At food exposure concentrations of
350 mg/kg-diet, 4 of 15 female bobwhite quail exposed to malathion for 21 weeks
displayed regressed ovaries and abnormally enlarged/flaccid gizzards. The same
observation was made in females at the 1200 mg/kg-diet level. A reduction in numbers of
eggs hatched from eggs set was observed at 350 mg/kg-diet. Reduced egg production,
viability of eggs, and embryo survival as well as an increase in the number of cracked
eggs (a possible indication of the weakening of the shell structure) was observed at
1200 mg/kg-diet. Effects to adults at 1200 mg/kg-diet included weight loss, reduced feed
consumption, some mortality, and clinical signs of toxicity.

Table 28. Avian reproduction studies (sourced from OPP data and ECOTOX studies meeting
minimum quality for database and OPP).				



%

LOAEL mg/kg-diet

NOAEL





Species

ai

Effected Parameters

mg/kg-diet

MRID

Classification





21WK LOEL=350 -regressed ovaries







Bobwhite
quail

96.4

and reduced egg hatch

At 1200 - reduced shell thickness, #

eggs laid , egg viability

110*

43501501

Core

Mallard duck

94.0

20 WK LOEL =2400
Growth and viability

1200

42782101

Core

Bantam

95

252 day LOEL 475
Chick growth, weight gain

237.5

ECOTOX

Supl.

chicken

No LOEL established for egg
production

475

ref. 37706

Bantam
chicken

100

56 day LOEL not determined for
growth, weight, or egg production

100

ECOTOX
ref. 38417

Supl.

*Endpoint used for quantitative assessment of risks.

Available data from the ECOTOX database include additional reproduction effects
information for the bantam chicken (domesticated chicken). The lowest NOAEL for
reproduction effects and chick growth in one study is 100 mg/kg-diet, the highest
exposure level tested. An additional study with the same species and malathion at similar
purity provided both a NOAEL and LOAEL for growth (475 mg/kg-diet and
237.5 mg/kg-diet) and a NOAEL for egg production (475 mg/kg-diet). When taken

132


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together, these studies suggest that effects on growth and egg production for this species
are not expected until exposure levels reach or exceed 475 mg/kg-diet in the bantam
chicken. This in turn suggests that the 100 mg/kg-diet NOEL is more an artifact of dose
selection than a true threshold for effects in the species.

The data described above indicate that a reproduction threshold dietary exposure of
110 mg/kg-diet represents the lowest effect threshold for use in quantitative risk
estimation.

4.2.2.3	Avian Development and Embryonic Effects Studies

In a University of Ottawa study 0.1 ml of solution injected into leghorn chicken eggs
proved lethal to 50% of the embryos after 7 days (dependent on age). Four to five-day old
embryos were most susceptible. Abnormalities included lack of feathers, smaller size,
and beak, plumage, and hind limb defects (Greenburg, J. and. N. Latham, 1968, as cited
in RED). In other studies where malathion was injected into eggs at 50 mg/egg, chicks
showed shortening of legs and bleaching of feathers (Marliac and Mutchler 1963, as cited
in RED). For hen eggs injected with 25, 100, 200, 300, 400, and 500 mg/kg of malathion
dissolved in acetone, hatchability was significantly reduced at higher levels with hatches
of 85%, 87%), 62%o, 71%o, 42%, and 6%, respectively (Dunachie and Fletcher, 1969, as
cited in RED). In an egg injection study with chick embryos (ECOTOX ref. 88908),
maloxon caused reduced survival of embryos at a concentration of 30 micromoles, and
those that did survive had severe abnormalities.

The effects of topical application of malathion (95% purity) to the eggs of mallard ducks
is reported in ECOTOX reference 35250. No adverse effects of embryo growth were
observed at exposures as high as a field equivalent exposure of 12.5 lb/acre (NOAEL).
The LOAEL for this study was 14 lb/acre).

The significance of effects associated with egg injection or topical application studies
cannot be reliably interpreted in the context of existing risk assessment exposure
assumptions. The exposure route for these studies cannot be related quantitatively to
existing exposure estimation methods which are either based on dietary concentrations or
daily oral dose estimation.

4.2.2.4	Avian Sublethal Effects Studies

Starlings fed 160 mg/kg-diet of malathion for 12 weeks showed 30% decrease in AChE
and 50%) decrease in 1 acetate dehydrogenase activity (ECOTOX ref. 35129). It should
be noted that dosages associated with this study are within the range of lethal effects
endpoints from available studies described in sections above.

Japanese quail (Coturnix japonica) fed malathion at 100 mg/kg-diet for 2 months
exhibited statistically significant increased in liver weights (p<0.05) and a significant
decrease in liver lipid and vitamin A content (p<0.001) (ECOTOX ref. 35083 ). It should
be noted that dosages associated with this study are within the range of lethal effects

133


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endpoints from available studies described in sections above and also very close to
available reproduction endpoints in quail.

House Sparrows (Passer domesticus) were offered treated grain with 5% ai malathion
dust. (Concentration 56.7g/56.8 kg of grain or approximately 100 mg/kg) to determine
deterrent effect. Oral doses were administered at 1, 2, 5, and 10 mg/bird in acetone or
approximately 50, 100, 250, and 500 mg/kg based on mean average weight. Sparrows
showed 75% reduction in feeding on treated seed us . untreated seed (4 g of treated seed
consumed vs. 21 g of untreated seed on average). Orally dosed birds showed increased
respiration, head droop, ejection of white fluid from mouth, and chronic and tonic
convulsions at 5 mg/kg or more. Birds that did recover did so in about 1 hour. AChE
inhibition was 83%, 75%, 50%, and 25% at 19 mg, 5 mg, 2 mg, and 1 mg per kg of body
weight, respectively within 5 minutes of ingestion. The 1 and 2 mg/kg dosed birds
recovered in 24 hours. Fifty-seven and 18% mortality was observed at 10 and 5 mg/kg
feed residue concentrations, respectively (ECOTOX ref. 37921).

4.2.2.5 Avian Field Studies

The following discussions of avian field studies with malathion and birds are excerpted
from the 2006 malathion RED. While these discussions do not in themselves establish
endpoints for incorporation into risk quotient calculations, they do provide in-field lines
of evidence that can be used to evaluate whether risk quotient-based interpretations of
malathion risks to birds (and by extension risks to amphibians) are appropriate.

In a Montana study, 52 live-trapped sharptailed grouse were given oral doses of dieldrin,
malathion, and lactose (controls) and released after tagging. They were subsequently
observed by capture or radio tracking. The lethal dose of malathion was observed to
occur between 200-240 mg/kg (note: this is consistent with lethal effects levels in
laboratory studies described above). Reaction to malathion occurred within 72 hours -
either death or full recovery. Sublethal signs included depression, slow reactions,
blinking, head nodding, and eventual heart or respiratory failure. Radio tracked grouse
displayed normal to severe reactions once released. Eight of twelve birds were recovered.
Predators are suspected in the disappearance of unrecovered birds (in one case a bird
moderately dosed with dieldrin was confirmed killed by a coyote). Grouse that were
dosed carried transmitters up to 12 days after release. All confirmed predator kills had
received what were considered sublethal doses of the test material. Other birds were
discovered to have been attacked and injured. The radio transmitters did not hinder all
birds as many were recovered in healthy condition. The sublethal effects of the malathion
and dieldrin on survivability are suspected. All controls survived and successfully bred
(MRID 113233).

An aerial application of malathion was made over Winnipeg in July 1983 as an ULV
solution (95%) malathion). Application rate was 210 ml/ha over the entire city to control
mosquitoes. Forty one sparrows and thirty nine pigeons were collected within 2 weeks of
spraying. Caged exposed sparrows were sacrificed and examined as well. Slight, but not
statistically significant, differences were noted (6-12% variation) in AChE levels of post
spray to prespray birds. Some reservation is expressed that study birds may all have been

134


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exposed to ground fogging applications prior to aerial application exposure (Kucera,
1987, as cited in the RED).

An experimental program to control melon flies on the Island of Bota (Northern Marianas
Islands) provided the USFWS with an opportunity to monitor avian populations while
subjected to exposure to malathion laced bait sprays (Cue-lure) that were aerially applied.
Applications were made at 3 week intervals beginning in Oct. 1988 at up to 5 -30
g/hectare depending on bait type. Of the 10 native species counted, 5 increased in number
and 5 decreased. The author was not certain if this was a normal annual fluctuation or one
caused by pesticides. Populations of the white throated ground dove, the Philippine turtle
dove, and possibly the bridled white eye were significantly lower in the following year.
No acute mortality was reported. The other 20 native species were observed and
populations appeared unaffected. Even insectivorous species did not appear to suffer
population decreases (Engbring 1989, as cited in the RED).

During 1964-1968 boll weevil control programs on cotton, game and non-game bird
populations near cotton fields were observed. Applications were aerial at 12 to 16 oz.
(approx. 1.2 lb ai) of technical malathion per acre, with up to 7 applications made at 5-22
day intervals. No major differences in weight gain were noted between treated and
control birds. No toxicant related mortality was noted after 3 applications of malathion.
No dead birds were located adjacent to fields. However, sublethal indicators other than
weight were not measured (Parsons and Davis 1971, as cited in the RED).

While these field effects studies are not quantitatively used as inputs to risk calculations,
they do provide information on the potential for malathion to produce adverse effects in
terrestrial vertebrates under actual field conditions.

4.2.3 Effects on Other Terrestrial Vertebrates Including Amphibians

In one reported study, oral ingestion of organophosphate pesticides and the resulting
percent mortality was measured for Carolina anoles. For malathion, the acute LD50 was
determined to be 2324 mg/kg (Hall and Clark, 1982, as cited in the RED). It should be
noted that this acute oral endpoint is higher than the results for birds.

Topical application (1.1 mg/kg-bw) of malathion (96.5% purity) daily for 30 days to
woodhouse toads (Bufo woodhousei) adversely affected frog growth, organ to
bodyweight somatic growth index, and produced cholinesterase inhibition (ECOTOX ref.
89016 and 89577. No mortalities were observed at this exposure level. An exposure level
of 11 mg/kg-bw with the same organism resulted in frog mortality. This exposure route is
not assessed by the usual terrestrial vertebrate exposure modeling tools. Discussion of the
implications of this study will be included in the risk discussion section (5) of this
document.

Topical application of malathion (96.5% purity) to bullfrogs (Rana catesbeiana) and
giant toads (Bufo marinus), produced lethality at a dose of 0.011 |ig/animal (ECOTOX
ref. 89001). This exposure route is not assessed by the usual terrestrial vertebrate

135


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exposure modeling tools. Discussion of the implications of this study will be included in
the risk discussion section of this document.

Intramuscular injection (990 |ig/kg) malathion (100% purity) in leopard frogs (Rana
pipiens) affected humeral immune response (ECOTOX ref. 68828). There are no
established methods for quantitatively relating immune response to assessment endpoints
of survival, growth, or fecundity in frogs. In addition, the intramuscular exposure route
does not represent an exposure route likely to occur in the field. Consequently, this study
is not considered quantitatively or qualitatively in the effects determination.

Wild caught salamanders (Plethodon glutinosus and P. cinerus) were exposed to
malathion via impregnated filter paper liners of their cages (ECOTOX ref. 40014). The
organisms exhibited significant (p<0.05) cholinesterase inhibition relative to controls at
application rates of 5.12 kg ai/ha and higher. Despite this cholinesterase depression,
neither species exhibited behavioral deficits (predatory striking behavior and evasion of
mechanical stimuli).

4.2.4 Toxicity to Terrestrial Insects and Other Invertebrates

Data for effects of malathion range from laboratory contact studies with pollinators and
lepidopterans to studies of field effects of the pesticide on insect populations under field
conditions. It is not surprising that application of an insecticide under field conditions
produces population reductions in insects. While the available laboratory studies do
provide background information to enhance the understanding of malathion toxicity to
invertebrates, the potential widespread use of the insecticide and field studies
demonstrating its insecticidal activity suggest that quantitative assessment of risks based
on laboratory effects data and uncertain exposure models would be unnecessary to
conclude that malathion produces invertebrate population reductions in treated areas.

4.2.4.1 Laboratory Studies

Results for registrant submitted and ECOTOX database non-target insect contact toxicity
studies are tabulated in Table 29. Many of the studies listed in ECOTOX did not provide
a quantitative estimate of the level of effect beyond a listing of near zero or near 100
percent. These studies have not been included in the following list as they do not provide
endpoints useful for quantitative risk assessment. The most sensitive contact LD50 value
is for the alfalfa leaf cutter bee 0.000285 ^g/animal.

Table 29. Non-target insect acute contact toxicity studies (sourced from OPP data and ECOTOX
studies meeting minimum quality for database and OPP). 		

Species

%ai

LD50 (lig ai/animal)

MRID

Classification

Honey bee

Apis mellifera

Tech

48 HR LD50 =0.20

05001991

Acceptable

Honey bee

Apis mellifera

Tech

96 HR LD50 =0.709

0001999

Acceptable

Honey bee

Apis mellifera

Tech

N.R. LD5o= 0.27
(0.22-0.29)

05004151

Acceptable

Honey bee

Apis mellifera

Tech

48 HR LD50 =0.38

05004003

Acceptable

136


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Species

%ai

LD?0 (u^ ai/animal)

IVI RID

Classification

Alfalfa leafcutter bee

Megachile rotundata

57

96 hrLDS0= 0.000285 *

ECOTOX ref.
39126

Supl.

Alkali bee Nomia
melanderi

57

96 hrLD50= 0.002052

ECOTOX ref.
39126

Supl.

Asiatic honey bee. 1 pis

cerana

100

72 hr LD5o= 0.46

ECOTOX ref.
58115

Supl.

Cabbage moth Mamestra
brassicae

94

24 hrLD50= 3.102

ECOTOX ref.
19582

Supl.

*Endpoint used for quantitative assessment of risks.

Martinez and Phenkowski (ECOTOX ref. 37837) reported immersion contact LC50
values (2 second immersion, 24 hour post exposure observation) for three insect species.
The LC50 values for the potato leafhopper (Empoasca fabae), tarnished plant bug (Lygus
lineolaris), and the predatory nabid (Reduviolus americoferus) were reported to be 41.32,
68.08, and 273.13 mg/1, respectively.

Panda and Sahu (ECOTOX ref. 52962) reported 96 hour LC50 values for the field
earthworm (Drawidawillsi) ranging from 15.1 to 18.8 mg/kg-soil. The same authors
(ECOTOX ref. 89517) reported a reduction in the population of the same earthworm
species relative to controls (measures at 60 days post application in laboratory colonies)
at a malathion soil concentration of 2.2 mg/kg.

4.2.4.2 Field Observations of Effects to Non-Target Insects

There are a number of field efficacy experiments involving applications of malathion to
control target insect pests. In addition, there are studies of malathion effects on field
populations of beneficial insect pollinators and insect predators. The following discussion
represents the results of such field studies extracted both from available ECOTOX
references and from summaries of literature reported in the RED.

Malathion (57% formulation) applied in the field at 1.4 kg ai/ha produced reductions in
alfalfa plant bugs (Adelphocoris lineolatus) relative to controls for up to 7 days post
application (ECOTOX ref. 91092).

Field populations of the aphid (Rhopalosiphum padi) were suppressed at a malathion
application rate of 1 lb ai/acre (ECOTOX ref. 89090).

Populations of the cotton aphid (Aphis gossypii) were not reduced relative to controls at a
malathion treatment rate of 0.82 lb ai/acre in cotton (ECOTOX ref. 88773).

Field application of malathion at a rate of 20 kg ai/ha had no adverse effect on population
abundance of gall flies (Asphondylia sesami, ECOTOX ref. 91627).

Malathion application in the field at a rate of 1.4 kg ai/ha produced population reductions
in Plagiognathus chrysanthemi and Lygus lineolaris (ECOTOX ref. 91092) and the
weevil {Hyperapostica, ECOTOX ref. 88952), but no adverse effects on populations of

137


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the parasitoid wasps (Aprostocetus bruchophagi and Mesopolobus bruchophagi) or the
trefoil seed chalcid (Bruchophagusplatypterus, ECOTOX ref. 89230).

Rangeland application of malathion at a rate of 0.342 kg ai/ha reduced orthopteran
population abundance relative to controls (ECOTOX ref. 52733).

During a six week period, baited sprays were applied with large droplet sizes (200-300
|im mean diameter). Malathion and maloxon were detected in water throughout the
monitoring period. Rain runoff to storm drains produced concentrations up to 583 |ig/L in
existing streams. Since bait sprays did not attract honeybees, it was believed that they
would be unaffected. However, non-targeted lacewings and dipterans were attracted
(mainly scavenger flies) to the bait and killed (Oshima 1982, as cited in RED).

Significant impact on honeybees was observed in a study conducted near San Francisco
using Mediterranean fruit fly/malathion bait sprays. Significant mortality was observed
during 48 hours post-application. Cause was determined to be pesticide contaminated
pollen (2.06 mg/kg (mean) and body residue levels of 0.9 - 5.3 mg/kg. Data from a
Stockton study also showed increased mortality which was partially attributable to nearby
application of Sevin (alfalfa fields), Kabbate, and sulfur dust (tomato fields). Reduced
flight activity was observed at both exposed sites after pesticide applications. Other
mortality may have occurred in the fields that was not measurable (Gary and Mussen
1984, as cited in RED).

In a University of California study, protein hydrosylate bait spray and malathion
applications were monitored and effects to non-target beneficial insect predators common
in urban trees were measured. Drop cloths were placed under trees and dead fallen insects
were collected and identified. 17 species of aphids, numerous dipterids, butterfly
(lepidopteran) larvae, spiders, cynipoidea, and hemiptera appeared to be heavily effected.
Also, pscopterans were reduced (Dahlsten 1983, as cited in RED).

In a Washington University study, 6 colonies of honeybees were placed in a 125 acre
alfalfa field 36 hours before aerial application. Two hives were covered with wet burlap
during application and burlap was removed 24 and 48 hours post application. Two hives
were left uncovered in the sprayed fields. Two other colonies were placed 2.25 miles
from the application site and one of these was covered with burlap for 48 hours. Eight
fluid oz of malathion ULV concentrate was applied per acre by aerial spray at 50 feet
altitude in a 125 foot swath on Aug 14. Package bee cages (150-200 bees) were also
placed in fields 2 and 7 hours after application for a 3 hour exposure period. Caged bees
were also exposed to foliar residue samples at intervals following the application. Bee
mortality was higher than normal for 4 days after application. Those covered with wet
burlap suffered the highest mortality 1 day after the covers were removed. Bees caged on
treated foliage also exhibited higher than normal mortality. Check (control) colonies
showed between 500 and 838 dead bees at hive entrances. Treated hive mortalities ranged
from 1298 (unprotected) to 2582 (entrance covered) honeybees. Bees which contacted
treated foliage showed from 100% (2 hours-1 day post application) mortality to 14%
mortality (4 day old residues) versus an average of 5% mortality for control bees.

138


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Malathion residues on foliage ranged from 28.8 mg/kg at application to 0.4 mg/kg (14
days after application). Residues remained over 25 mg/kg for 4 days following
application after which a rainfall event occurred. Grasshopper populations were greatly
reduced from 12/sq. yd. to less than 1/sq yd. three days after treatment. Lygus bugs were
also controlled for up to 3 weeks. Interestingly, the target organisms, Alfalfa weevils and
larvae, were not totally controlled. Lady beetles populations were reduced for up to 3
weeks following applications (Johansen 1965, as cited in RED).

4.2.5	Toxicity to Plants

The risk assessment process relies predominantly on effects endpoints associated with
seedling emergence, growth, and plant viability. There are no submitted registrant data
for malathion and terrestrial plants. A review of the available ECOTOX data meeting
OPP data quality criteria, did not show any effects on emergence, growth, and plant
viability for any dicot plants species under any application conditions. For monocots,
ECOTOX ref. 70355 reports statistically significant (P<0.01) reductions in corn root
length in seedlings grown for 21-days in a pure quartz sand matrix treated with 30 mg/kg
malathion. However, this root length reduction did not translate into any adverse effect in
above ground growth of the plants or deficits in root or shoot dry weight. Given the
extreme growing conditions in pure quartz sand and the lack of frank effects on plant
growth this study was judged not to demonstrate biologically relevant effects of
malathion to monocot plants that would be manifested under field conditions.

Another study of malathion exposure in monocots involved the soaking of onion bulbs in
a 5 mg/L malathion solution (ECOTOX ref. 8571391). Under these conditions, onion
root tip cells showed some alteration in mitotic index elative to untreated controls. This
study involves a non-field pertinent exposure scenario and the cellular level effects are
not readily related to assessment endpoints for terrestrial plants.

Immersion of wheat seeds in aqueous solutions of malathion resulted in reductions in
seedling shoot length (ECOTOX ref. 2240256). The LOAEC for this effect was 100
mg/L and the NOAEC was 500 mg/L. Again, as in the onion study, immersion in an
aqueous solution does not represent a field pertinent exposure scenario.

As a consequence of these findings, the risk assessment assumes that malathion will not
produce adverse effects on plants at field relevant levels and conditions of exposure.

4.2.6	Terrestrial Wildlife Field Incidents

The Agency reviews and records all wildlife mortality incidents reported independently
or under 6a2 provisions of FIFRA regarding use of pesticides or pesticide mixtures.

These incidents are reported to the Agency by a variety of sources including registrants,
private organizations and local, state, or federal agencies. A summary of all terrestrial
incidents reviewed by the Agency following use of malathion products or mixtures is
provided in Table 30.

139


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Table 30. Incidence reports potentially attributable to malathion.

Location and Date

Incident

Description

Probability

Oregon, 1/1/85

1000130

5000 acres of alfalfa treated with
malathion by USDA-extensive mortality
of honeybees collecting nectar from
blossoms reported

Probable

Florida, 1997 Medfly
Program,

Hillsborough County
area

USDA
Medfly
Incident
Report

Three incidents involving mortality of
ducks were reported along with over 40
fish kills that were investigated. All
occurred where malathion bait
formulations were used near ponds.
6/22-10 to 14 Ducks killed-Seminole
Hts.-baits used

6/14-Duck kill-NW Hillsborough sector-
baits used

6/25-Duck kill-Rodrie pond-baits applied
aerially

Possible- but
unlikely.

Only routes believed
to offer logical
exposure route- oral
ingestion of baits or
dermal exposure-
residue concentration
too low to =LD50.

The incidents where duck mortality was reported in Florida medfly program
investigations were determined to be more likely caused by some other toxicant. Though
fish kills did occur in the ponds, actual residues were well under those which would be
expected to cause oral toxicity in mallard duck (1485 mg/Kg). In the case of the June 14
fish kill, an oily substance was observed on the moribund ducks. Park service personnel
had also sprayed herbicides near the pond (Glyphosate and Copper). Maximum malathion
concentration on vegetation was only 3.0 mg/kg far below avian toxicity thresholds. The
Agency would tend to agree with USDA that malathion was not the primary cause of
death in the duck kill incidents

4.3 Maloxon Toxicity

One of the degradates of malathion under selected environmental conditions is the oxon
of the molecule, maloxon. Limited toxicity data are available for selected taxonomic
groups and are summarized in the following sections.

4.3.1 Aquatic Organism Toxicity for Maloxon
Table 31 presents available toxicity data for maloxon for aquatic organisms.

Table 31. Aquatic organism maloxon toxicity studies (sourced from ECOTOX studies meeting
minimum quality for database and OPP).			i	

Species Tested

%
ai

Du ration
hours

ECSo or LCSo Jig/L

Reference
MRID or
ECOTOX

Classification

African clawed frog

Xenopus laevis.



96

900

ECOTOX ref.
66506

Supl.

Yellow-legged frog Rana
boylii



96

23

*

Supl.

Medaka

Oryzias latipes



48

200

ECOTOX ref.
18396

Supl.

Carp

Cyprinus carpio



48

1600

ECOTOX ref.
86

Supl.

140


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Species Tested

%
ai

Du ration
hours

ECSo or LCso U^/L

Reference
MRID or
ECOTOX

Classification

Perch

Perca fluviatilis



48

150

ECOTOX ref.
86

Supl.

Roach

Rutilus rulitus



48

1100

ECOTOX ref.
86

Supl.

Midge

Chironomus riparius



24

5.4

ECOTOX ref.
86

Supl.

*Sparling, D.W. and G. Fellers. 2006 Comparative toxicity of chlorpyrifos, diazinon, malathion and their
oxon derivatives to larval Rana boylii. Environmental Pollution (Article in Press; available online at
www, sciencedirect. coin).

4.3.2	Terrestrial Organism Toxicity for Maloxon

No acute or chronic maloxon toxicity data were available for terrestrial vertebrates.

4.3.3	Establishing Relationships between Malathion and Maloxon Toxicity

There are a limited number of situations where acute toxicity for malathion and maloxon
have been determined for the same test species (Table 32). In most cases maloxon is
observed to be more toxic than malathion. The strongest comparison of relative potencies
within these species is with the larval yellow-legged frog tests, which were conducted in
the same lab with the same stock organisms. Because this comparison has the highest
degree of confidence and is the most conservative, the potency ratio of 92.9 malathion to
maloxon was used to adjust other effects endpoints for malathion to maloxon potency
equivalency.

Table 32. Within species comparisons of malathion and maloxon acute toxicity.

Species Tested

Malathion

LCS0 Hg/L

Maloxon

LCS0 Mg/L

Ratio of Malathion to Maloxon Toxicitv

Carp

Cyprinus carpio

6590 -23180

1600

4.1-14.5

Medaka

Oryzias latipes

9700

200

48.5

Yellow-legged frog Rana
boylii

2137

23

92.9

Midge

Chironomus riparius

1.9-440

5.4

0.35-81.5

The only exception to the application of the above relative potency adjustment factor was
for plants, where the mechanism of action is not likely to be related to the anti-acetyl
cholinesterase activity of the phosphate ester or thioester of maloxon or malathion.
Therefore, in this case of plant toxicity prediction malathion and maloxon are assumed to
be equipotent.

141


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5. Risk Characterization

Risk characterization is the integration of the exposure and effects characterizations to
determine the potential ecological risk from various malathion use scenarios within the
action area and likelihood of direct and indirect effects on the CRLF. The risk
characterization provides estimation and description of the likelihood of adverse effects;
articulates risk assessment assumptions, limitations, and uncertainties; and synthesizes an
overall conclusion regarding the effects determination (i.e., "no effect," "may affect, but
not likely to adversely affect", or "likely to adversely affect") for the CRLF.

5.1 Risk Estimation

Risk is estimated by calculating the ratio of the EECs and the appropriate toxicity
endpoint. This value is the risk quotient (RQ), which is then compared to pre-established
levels of concern (LOC) for each category evaluated (Table 33). The RQ methodology,
LOCs, and specific details of calculation are contained in Appendix G. The highest EECs
and most sensitive endpoints are used to determine the screening level RQ. Using these
two values theoretically results in a conservative estimate of risk.

Table 33. Levels of concern for terrestrial and aquatic organisms.

Taxa

Acute LOC

Chronic LOC

Avian1 (terrestrial phase amphibians)

0.1

1

Mammalian2

0.1

1

Terrestrial plants3

1

N.A.

Aquatic Animals4 (aquatic phase amphibians)

0.05

1

Insects5

0.05

1

Used in RQ calculations:

1	LD50 and estimated NOEL

2	LD50 and NOEC

3ec25

4	LC50/EC50 and estimated and reproductive NOEC

5	LD50 per EFED's CRLF Steering Committee

5.1.1 Aquatic Phase Direct Effects

Direct effects to the aquatic phase CRLF are assessed in Table 34 for both malathion and
maloxon (drift calculated separately). RQs calculations are based on EECs from
PRZM/EXAMS (application to land) and EFED Rice Guidance document methods
(direct applications to water) and the appropriate assessment endpoints.

142


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Table 34. Assessment of direct effects on the aquatic phase California Red-legged Frog (CRLF) from malathion (estimate includes drift component) and
maloxon (drift calculated separately).		

Maximum

Risk Quotients (RQs) for Aquatic Phase CRLF Direct Effects

Malathion



Maloxon

Application

Malathion

Dcgradatc Fraction2

Impurity Fraction3

Scenario Group: Crop/Site

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine,
Trefoil, and Vetch

Air: 2
Other: 2

16$
8.9$

96#
41#

128$

506#

0.094*
.019

0.31
.063

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

88$
22$

1320#
273#

198$

507#

.71$
.14*

2.3#
.47

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

72$
15$

462#
94#

9.5$

34#

.59$
.12*

2.0#
.39

4. Chestnut

Air: 5
Other: 5

28$
5.6$

248#
50#

7.0$

25#

.24*
.047

.78
.16

5. Almond

Air: 1.25
Other: 4

12$
23$

92#
134#

79$
253$

413#
1320#

.059*
.038

.20
.13

6. Date

Air: 1
Other: 2

4.9$
1.9$

37#
15#

2.2$
4.3$

7.6#
15#

.047
.019

.16
.063

7. Filbert (Hazelnut)

Air: .625
Other: .625

3.6$
.73$

23#
4.7#

.47*

1.7#

.029
.006

.098
.020

8. Avocado

Air: 9
Other: 9

52$
10$

234#
47#

.52$

1.3#

.42*
.085*

1.4#
.28

9. Citrus, Citrus Hybrids other than
Tangelo, Grapefruit, Kumquat, Lemon,
Lime, Orange, Tangelo, and Tangerines

Air: 25
Other: 25

165$
33$

1207#
248#

38$

132#

1.2$
.24*

3.9#
.78

10. Amaranth - Chinese, Broccoli
(Unspecified, Chinese, and Raab),
Cabbage (Unspecified and Chinese),
Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel),
Horseradish, Kale, Kohlrabi, Mustard,
Mustard Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

15$
3.0$

226#
45#

.84$

2.7#

.12*
.024

.39
.078

143


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Maximum

Risk Quotients (RQs) for Aquatic Phase CRLF Direct Effects



Malathion





Maloxon



Application

Malathion

Degradatc Fraction2

Impurity

Fraction3



Rates1

Acute

Chronic

Acute

Chronic

Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

60-dav

Peak

60-dav

Peak

60-dav

11. Corn (Unspecified, Field, Pop, and
Sweet) and Millet (Foxtail)

Air: 1.5
Other: 1.5

13$
2.7$

54#
11#

3.7$

13#

.071*
.014

.23
.047

12. Cotton

Air: 4
Other: 4

34$
8.9$

834#
167#

152$

269#

.19*
.038

.63
.13

15. Apricot

Air: 10
Other: 10

58$
12$

464#
93#

<001

.002

.47*
.094*

1.6#
.31

16. Nectarine and Peach

Air: 9
Other: 9

50$
9.9$

372#
74#

1.6$

3.7#

.42*
.085*

1.4#
.28

17. Cherry

Air: 8
Other: 8

49$
9.8$

580#
116#

<001

.002

.38*
.075*

1.3#
.25

18. Fig

Air: 2.5
Other: 2.5

14$
2.9$

74#
15#

.041

.097

.12*
.024

.39
.078

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

6.9$
1.7$

123#
29#

.40*
.48*

.97
1.2#

.059*
.014

.20
.047

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

4.7$
.94$

96#
19#

.70$
1.4$

2.2#
4.5#

.035
.014

.12
.047

21. Papaya

Air: .175
Other: .175

1.1$
.22*

22#
4.5#

.16*

.52

.008
.002

.027
.005

22. Garlic and Leek

Air: 2
Other: 2

17$
9.9$

140#
44#

111$

272#

.094*
.019

.31
.063

23. Grapes

Air: 2.75

15$

62#

<001

<001

.13*

.43

Other: 27.47

30$

125#

<001

.002

.26*

.86

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

15$
3.1$

121#
25#

.071*

.24

.12*
.024

.39
.078

27. Swiss Chard, Chervil, Endive















(Escarole), Lettuce, Head Lettuce, Leaf















Lettuce (Black Seeded Simpson, Salad
Bowl, Etc.), Orach (Mountain

Air: 2
Other: 2

33$
24$

251#
107#

547$

1764#

.094*
.019

.31
.063

Spinach), Parsley, Roquette (Arrugula),
Salsify, and Spinach















144


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Maximum

Risk Quotients (RQs) for Aquatic Phase CRLF Direct Effects



Malathion





Maloxon



Application

IMalathion

Degradatc Fraction2

Impurity

Fraction3



Rates1

Acute

Chronic

Acute

Chronic

Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

60-dav

Peak

60-dav

Peak

60-dav

28. Peppermint

Air: 1
Other: 1

6.2$
1.2$

49#
9.9#

.017

.056

.047
.009

.16
.031

29. Eggplant

Air: 3.5
Other: 3.5

21$
4.3$

183#
43#

49$

149#

.17*
.033

.55
.11

30. Pumpkin

Air: 2
Other: 2

12$
2.4$

132#
28#

35$

87#

.094*
.019

.31
.063

31. Cucumber, Cucurbit Vegetables,















Melons - Unspecified, Cantaloupe,
Honey dew, Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persian),
and Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

11$
2.8$

126#
29#

41$

106#

.088*
.018

.29
.059

32. Onion (Unspecified and Green),
Radish, and Shallot

Air: 2
Other: 2

13$
5.4$

162#
39#

57$

169#

.094*
.019

.31
.063

33. Potato - White/Irish

Air: 3
Other: 3

17$
3.3$

171#
34#

.038

.068

.14*
.028

.47
.094

34. Turnip

Air: 2.5
Other: 2.5

14$
2.9$

164#

33#

<001

.002

.12*
.024

.39
.078

35. Parsnip and Rutabaga

Air: 2
Other: 2

10$
2.1$

93#
19#

.072*

.19

.094*
.019

.31
.063

36. Sweet Potato

Air: 1.875

10$

44#



8.5#

.088*

.29

Other: 1.875

2.0$

9.2#

J .Oj>

.018

.059

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland,
Sudangrass, and Timothy

Air: 1.25
Other: 1.25

14$
2.9$

55#
11#

.16*

.58

.059*
.012

.20
.039

40. Beets, Cowpea/Blackeyed Pea, and
Peas (Unspecified and Field)

Air: 2.5
Other: 2.5

15$

3$

189#
38#

.007

.024

.12*
.024

.39
.078

41. Carrot (Including Tops), Celtuce,
Fennel, and Pepper

Air: 2
Other: 2

14$
2.8$

208#
42#

10$

35#

.094*
.019

.31
.063

145


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Maximum

Risk Quotients (RQs) for Aquatic Phase CRLF Direct Effects

Malathion



Maloxon

Application

IMalathion

Degradatc Fraction2

Impuritv Fraction3

Scenario Group: Cro|)/Sitc

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

42. Beans, Beans - Dried-Type, Beans -
Succulent (Lima), and Beans -
Succulent (Snap)

Air: 1.75
Other: 1.75

11$
2.2$

79#
16#

.36*

1.2#

.083*
.017

.27
.055

43. Celery

Air: 1.5
Other: 1.5

16$
11$

74#
38#

139$

441#

.071*
.014

.23
.047

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

15$
12$

226#
84#

165$

765#

.059*
.012

.20
.039

45. Anise

Air: .9375
Other: .9375

5.6$
1.1$

97#
19#

7.4$

26#

.044
.009

.15
.029

46. Strawberry

Air: 2
Other: 2

13$
2.6$

191#
38#

.11*

.32

.094*
.019

.31
.063

47. Sugar Beet

Air: 1.875
Other: 1.875

17$
8.1$

162#
49#

128$

409#

.088*
.018

.29
.059

48. Tomato

Air: 3.5
Other: 3.5

20$
4.0$

173#
35#

.48*

1.5#

.17*
.033

.55
.11

49. Okra

Air: 1.5
Other: 1.5

8.6$
1.7$

96#
19#

.37*

.89

.071*
.014

.23
.047

51. Sorghum

Air: 1.5
Other: 1.5

7.8$
1.6$

45#
8.9#

.21*

.51

.071*
.014

.23
.047

52. Barley, Cereal Grains, Oats, Rye,
and Wheat

Air: 1.25
Other: 1.25

20$
15$

126#
77#

155$

822#

.059*
.012

.20
.039

53. Gooseberry

Air: 16
Other: 16

103$
21$

969#
194#

.010

.035

.75$
.15*

2.5#
.50

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and Raspberry
(Black - Red)

Air: 4
Other: 4

26$
5.1$

242#
48#

.002

.009

.19*
.038

.63
.13

55. Blueberry

Air: 2.5
Other: 2.5

19$
3.9$

150#
30#

3.7$

13#

.12*
.024

.39
.078

56. Caneberries and Currant

Air: 2
Other: 2

13$
2.6$

121#
24#

.001

.004

.094*
.019

.31
.063

146


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Maximum

Risk Quotients (RQs) for Aquatic Phase CRLF Direct Effects



Malathion





Maloxon



Application

Malathion

Degradatc Fraction2

Impurity

Fraction3



Rates1

Acute

Chronic

Acute

Chronic

Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

60-dav

Peak

60-dav

Peak

60-dav

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

4.9$
.98$

91#
18#

.002

.006

.035
.007

.12
.023

58. Mint and Spearmint

Air: 1
Other: 1

5.7$
1.1$

41#
8.2#

3.3$

11#

.047
.009

.16
.031

59. Rice and Wild Rice

Air: 1.5625

2380$

7886#

24$

78#

.074*

.24

Other: 1.5625

2380$

7886#

.015

.049

61. Water Cress

Air: 2

3046$

10,094#

30$

100#

.094*

.31

Other: 2

3046$

10,094#

.019

.063





Non-

¦agricultural Uses







Forestry. Christmas Tree Plantations,
Pine (Seed Orchard), and Slash Pine
(Forest)

Air: 3.2
Other: 3.2

95$
85$

466#
339#

971$

3628#

.15*
.030

.50
.10

Mosquito Control. Intermittently















Flooded Areas/Water,















Lakes/Ponds/Reservoirs (with Human















or Wildlife Use),
Lakes/Ponds/Reservoirs (without
Human or Wildlife Use), Polluted

Air: .6
Other: .6

914$
914$

3028#
3028#

9.1$

30#

.028
.006

.094
.019

Water, and















Swamps/MarshesAV etlands/Stagnant















Water















Nursery. Outdoor Nursery

Air: 2.254
Other: 2.254

15$
2.9$

143#
29#

3.3$

8.1#

.11*
.021

.35
.070

Public Health and Medfly Control.















Nonagricultural Areas (Public Health
Use), Urban Areas, and Wide
Area/General Outdoor Treatment

Air: .6119
Other: .1361

25$
5.0$

267#
44#

534$
119$

4425#
983#

.029
.001

.096
.004

(Public Health Use)















147


-------


Maximum

Risk Quotients (RQs) for Aquatic Phase CRLF Direct Effects



Malathion





Maloxon



Application

Malathion

Degradatc Fraction2

Impurity

Fraction3



Rates1

Acute

Chronic

Acute

Chronic

Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

60-dav

Peak

60-dav

Peak

60-dav

Residential. Household/Domestic















Dwellings Outdoor Premises,















Ornamental and/or Shade Trees,















Ornamental Herbaceous Plants,
Ornamental Lawns and Turf,

Other: ,25s

.31*

6.9#

.22*

.72

.002

.008

Ornamental Non-flowering Plants,
Ornamental Woody Shrubs and Vines,















and Urban Areas















Rights-of-way. Nonagricultural Rights-
of-way/Fencerows/Hedgerows and
Nonagricultural Uncultivated

Air: .9281
Other: .9281

5.0$
1.0$

45#
8.9#

.021

.067

.044
.009

.15
.029

Areas/Soils















Turf. Golf Course Turf

Air: 1.25

6.8$

117#

.71$

2.4#

.059*

.20

(Bermudagrass)

Other: 1.25

1.4$

23#

.012

.039

"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2Maloxon application rate is assumed to be 10.7% of malathion application rate.

3	Maloxon as an impurity in drift is assumed to be 0.1% of malathion in drift.

4	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

5	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

*	Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

#	Chronic RQ >1.0 for listed and non-listed species.

148


-------
For malathion, the PRZM/EXAMS EECs includes the drift, runoff, and groundwater
components. The assessment endpoints are 0.59 |ig/L (acute) and 0.014 |ig/L (chronic).
Malathion acute RQs range from 1.1 to 160 for aerial and air-blast application methods to
land (5% spray drift assumed), 0.22 to 85 for other applications to land (1% spray drift
assumed), and 910 to 3000 for direct applications to water. Malathion chronic RQs range
from 22 to 1320 for aerial and air-blast application methods to land (5% spray drift
assumed), 4.5 to 340 for other applications to land (1% spray drift assumed), and 3000 to
10,000 for direct applications to water. All of the uses modeled with aerial and air-blast
application methods to land and all of the uses with direct application to water exceed
both the LOCs for listed (0.1) as well as non-listed (0.5) species. All of the uses modeled
with other application methods to land exceed both the LOCs for listed (0.1) as well as
non-listed (0.5) species, except residential (RQ = 0.31) and papaya (RQ = 0.22) uses,
which only exceeded the LOC for listed species. Malathion EECs would need to be
reduced by factors of 11 to 1600 for aerial and air-blast application methods to land, 2.2
to 850 for other applications to land, and 9100 to 30,000 for applications to water in order
to not exceed the listed species LOC (0.05) for acute affects (the most sensitive
assessment endpoint for direct aquatic phase effects).

For maloxon, the impurity fraction (based on maloxon as an impurity) had to be
calculated separately from the degradate fraction in PRZM/EXAMS. (When calculated
this way the peak and maximum 21-day and 60-day averages may occur at different times
for the impurity fraction and degradate fraction EECs, therefore, the impurity and
degradate EECs can not be validly added to estimate a total exposure.) The maloxon
assessment endpoints are 0.0064 |ig/L (acute) and 0.00015 |ig/L (chronic). Maloxon
acute RQs based on the degradate EECs range from 7 x 10"5 to 970 for application
methods to land (spray drift assumptions do not apply). Maloxon acute RQs based on the
impurity EECs range from 8 x 10"3 to 1.2 for aerial and air-blast application methods to
land (5% spray drift assumed) and 1 x 10"3 to 0.26 for other applications to land (1%
spray drift assumed). Maloxon chronic RQs based on the degradate EECs range from
2 x 10"4 to 4400 for application methods to land. Maloxon chronic RQs based on the
impurity EECs range from 0.027 to 3.9 for aerial and air-blast application methods to
land (5% spray drift assumed) and 4 x 10"3 to 0.86 for other applications to land (1%
spray drift assumed). RQs for direct applications to water (spray drift assumptions do not
apply) range from 9.1 to 30 (acute) and 30 to 100 (chronic).

Several maloxon EECs produce higher RQs than the respective malathion RQs. Because
maloxon is both an impurity (assumed 1% of applied malathion) and a degradate
(assumed 10.7% of applied malathion), uses that a have a large drift contribution to their
total EECs tend to have higher malathion than maloxon RQs, while uses that a have a
large runoff and groundwater contributions to their total EECs tend to have higher
maloxon than malathion RQs. Seventeen of the uses modeled with aerial and air-blast
application rates to land have higher acute maloxon RQs than their respective malathion
RQs. Of the 6 uses that have an 'other' application rates to land that differ from the aerial
and air-blast application rate, 4 uses have higher acute maloxon RQs than their respective
malathion RQs. Eleven of the uses modeled with aerial and air-blast application rates to
land have higher chronic maloxon RQs than their respective malathion RQs. Of the 6

149


-------
uses that have an 'other' application rates to land that differ from the aerial and air-blast
application rate, 3 uses had higher chronic maloxon RQs than their respective malathion
RQs. None of the acute or chronic maloxon RQs based on the impurity EECs are greater
than the respective malathion RQs.

5.1.2 Aquatic Phase Indirect Effects

Potentially, indirect effects on the aquatic phase of the CRLF include toxic effects on
prey items including fish, invertebrates, and aquatic plants. Effects on aquatic plants may
also indirectly affect aquatic phase amphibians through reductions in shelter/cover
opportunities. Terrestrial plant effects may indirectly result in alterations in riparian
habitat, which could limit sheltering opportunities as well as water quality. The following
sections present the results of RQ evaluations for fish, aquatic invertebrate, aquatic plant,
and terrestrial plant taxonomic groups.

5.1.2.1 Aquatic Phase Indirect Effects via Reduction in Food Items

Indirect effects to the aquatic phase CRLF from reduction in food items are assessed in
Table 35 (fish) and 36 (invertebrates) for both malathion and maloxon (impurity
calculated separately). RQs calculations are based on EECs from PRZM/EXAMS
(application to land) and EFED Rice Guidance document methods (direct applications to
water) and the appropriate assessment endpoints.

Freshwater Fish

For malathion, the PRZM/EXAMS EECs include the drift, runoff, groundwater
components. For freshwater fish, the assessment endpoints are 4 |ig/L (acute) and 0.098
|ig/L (chronic). Malathion acute RQs range from 0.16 to 24 for aerial and air-blast
application methods to land (5% spray drift assumed), 0.032 to 13 for other applications
to land (1% spray drift assumed), and 130 to 450 for direct applications to water.
Malathion chronic RQs range from 3.2 to 190 for aerial and air-blast application methods
to land (5% spray drift assumed), 0.64 to 48 for other applications to land (1% spray drift
assumed), and 430 to 1400 for direct applications to water. All of the uses modeled with
aerial and air-blast application methods to land and all of the uses with direct application
to water exceed both the LOCs for listed (0.1) as well as non-listed (0.5) species. All of
the uses modeled with other application methods to land exceed both the LOCs for listed
(0.1) as well as non-listed (0.5) species, except residential (RQ = 0.31) and papaya (RQ =
0.22) uses, which only exceeded the LOC for listed species. Malathion EECs would need
to be reduced by factors of 11 to 1600 for aerial and air-blast application methods to land,
2.2 to 850 for other applications to land, and 9100 to 30,000 for applications to water in
order to not exceed the listed species LOC for acute affects.

150


-------
Table 35. Assessment of indirect effects on the aquatic phase California Red-legged Frog (CRLF) for malathion (estimate includes drift component) and
maloxon (drift calculated separately) to freshwater fish.	

Maximum

Risk Quotients (RQs) for Freshwater Fish

Malathion



Maloxon

Application

Malathion

Dcgradatc Fraction2

Impurity Fraction3

Scenario Group: Crop/Site

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Agricultural Uses

1. Alfalfa, Clover, Lespedeza,
Lupine, Trefoil, and Vetch

Air: 2
Other: 2

2.4$
1.3$

14#
5.9#

19$

72#

0.014
.003

0.045
.009

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

13$
3.2$

189#
39#

29$

72#

.10*
.021

.33
.067

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

11$
2.1$

66#
13#

1.4$

4.8#

.087*
.017

.28
.056

4. Chestnut

Air: 5
Other: 5

4.1$
.83$

35#
7.2#

1.0$

3.5#

.035
.007

.11

.022

5. Almond

Air: 1.25
Other: 4

1.8$
3.3$

13#
19#

12$
37$

59#
189#

.009
.006

.028
.018

6. Date

Air: 1
Other: 2

.72$
.29*

5.3#
2.2#

.32*
.64$

1.1#
2.2#

.007
.003

.022
.009

7. Filbert (Hazelnut)

Air: .625
Other: .625

.53$
.11*

3.3#
.67

.070*

.24

.004
<001

.014
.003

8. Avocado

Air: 9
Other: 9

7.6$
1.5$

33#
6.7#

.077*

.18

.063*
.013

.20
.04

9. Citrus, Citrus Hybrids other than
Tangelo, Grapefruit, Kumquat,
Lemon, Lime, Orange, Tangelo, and
Tangerines

Air: 25
Other: 25

24$
4.9$

172#
35#

5.6$

19#

.17*
.035

.56
.11

151


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Maximum

Risk Quotients (RQs) for Freshwater Fish



IMalathion





Maloxon



Application

IMalathion

Dcgradatc Fraction2

Impurity

Fraction3



Rates1

Acute

Chronic

Acute

Chronic

Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

60-dav

Peak

60-dav

Peak

60-dav

10. Amaranth - Chinese, Broccoli















(Unspecified, Chinese, and Raab),
Cabbage (Unspecified and Chinese),
Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel),
Horseradish, Kale, Kohlrabi,

Air: 2.5
Other: 2.5

2.2$
.44*

32#
6.5#

.12*

.38

.017
.003

.056
.011

Mustard, Mustard Cabbage (Gai
Choy/Pak-Choi), and Purslane
(Garden and Winter)















11. Corn (Unspecified, Field, Pop,
and Sweet) and Millet (Foxtail)

Air: 1.5
Other: 1.5

2.0$
.40*

7.8#
1.6#

.55$

1.9#

.010
.002

.033
.007

12. Cotton

Air: 4

5.0$

119#

22$

38#

.028

.089

Other: 4

1.3$

24#

.006

.018

15. Apricot

Air: 10
Other: 10

8.5$
1.7$

66#
13#

<001

<001

.070*
.014

.22
.045

16. Nectarine and Peach

Air: 9
Other: 9

7.3$
1.5$

53#
11#

.23*

.54

.063*
.013

.20
.040

17. Cherry

Air: 8
Other: 8

7.2$
1.4$

83#
17#

<001

<001

.056*
.011

.18

.036

18. Fig

Air: 2.5
Other: 2.5

2.1$
.42*

11#
2.1#

.006

.014

.017
.003

.056
.011

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

1.0$
.24*

18#
4.2#

.059*
.071*

.14
.17

.009
.002

.028
.007

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

.70$
.14*

14#
2.7#

.10*
.21*

.32
.64

.005
.002

.017
.007

21. Papaya

Air: .175
Other: .175

.16*
.032

3.2#
.64

.024

.075

.001
<001

.004
<001

22. Garlic and Leek

Air: 2
Other: 2

2.5$
1.5$

20#
6.2#

16$

39#

.014
.003

.045
.009

23. Grapes

Air: 2.75

2.2$

8.9#

<001

<001

.019

.061

Other: 27.47

4.5$

18#

<001

<001

.038

.12

152


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Maximum

Risk Quotients (RQs) for Freshwater Fish

Malathion



Maloxon

Application

Malathion

Dcgradatc Fraction2

Impuritv Fraction3

Scenario Group: Cro|)/Sitc

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

2.3$
.46*

17#
3.5#

.01

.034

.017
.003

.056
.011

27. Swiss Chard, Chervil, Endive
(Escarole), Lettuce, Head Lettuce,
Leaf Lettuce (Black Seeded Simpson,
Salad Bowl, Etc.), Orach (Mountain
Spinach), Parsley, Roquette
(Arrugula), Salsify, and Spinach

Air: 2
Other: 2

4.9$
3.6$

36#
15#

81$

252#

.014
.003

.045
.009

28. Peppermint

Air: 1
Other: 1

.91$
.18*

7.0#
1.4#

.002

.008

.007
.001

.022
.004

29. Eggplant

Air: 3.5
Other: 3.5

3.1$
.63$

26#
6.2#

7.2$

21#

.024
.005

.078
.016

30. Pumpkin

Air: 2
Other: 2

1.7$
.35*

19#
4.0#

5.1$

12#

.014
.003

.045
.009

31. Cucumber, Cucurbit Vegetables,
Melons - Unspecified, Cantaloupe,
Honey dew, Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persia
n), and Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

1.6$
.41*

18#
4.1#

6.0$

15#

.013
.003

.042
.008

32. Onion (Unspecified and Green),
Radish, and Shallot

Air: 2
Other: 2

2.0$
.80$

23#
5.6#

8.4$

24#

.014
.003

.045
.009

33. Potato - White/Irish

Air: 3
Other: 3

2.4$
.49*

24#
4.9#

.006

.010

.021
.004

.067
.013

34. Turnip

Air: 2.5
Other: 2.5

2.1$
.43*

23#
4.7#

<001

<001

.017
.003

.056
.011

35. Parsnip and Rutabaga

Air: 2
Other: 2

1.5$
.31*

13#
2.7#

.011

.027

.014
.003

.045
.009

36. Sweet Potato

Air: 1.875
Other: 1.875

1.5$
.30*

6.2#
1.3#

.54$

1.2#

.013
.003

.042
.008

153


-------
Maximum

Risk Quotients (RQs) for Freshwater Fish

Malathion



Maloxon

Application

Malathion

Dcgradatc Fraction2

Impuritv Fraction3

Scenario Group: Cro|)/Sitc

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland,
Sudangrass, and Timothy

Air: 1.25
Other: 1.25

2.1$
.43*

7.8#
1.6#

.024

.082

.009
.002

.028
.006

40. Beets, Cowpea/Blackeyed Pea,
and Peas (Unspecified and Field)

Air: 2.5
Other: 2.5

2.2$
.44*

27#
5.4#

.001

.003

.017
.003

.056
.011

41. Carrot (Including Tops), Celtuce,
Fennel, and Pepper

Air: 2
Other: 2

2.1$
.42*

30#
6.0#

1.5$

5.0#

.014
.003

.045
.009

42. Beans, Beans - Dried-Type,
Beans - Succulent (Lima), and Beans
- Succulent (Snap)

Air: 1.75
Other: 1.75

1.6$
.33*

11#

2.3#

.053*

.18

.012
.002

.039
.008

43. Celery

Air: 1.5
Other: 1.5

2.4$
1.6$

11#
5.4#

21$

63#

.010
.002

.033
.007

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

2.3$
1.7$

32#
12#

24$

109#

.009
.002

.028
.006

45. Anise

Air: .9375
Other: .9375

.83$
.17*

14#
2.8#

1.1$

3.7#

.007
.001

.021
.004

46. Strawberry

Air: 2
Other: 2

1.9$
.39*

27#
5.5#

.016

.046

.014
.003

.045
.009

47. Sugar Beet

Air: 1.875
Other: 1.875

2.5$
1.2$

23#
7.0#

19$

58#

.013
.003

.042
.008

48. Tomato

Air: 3.5
Other: 3.5

3.0$
.60$

25#
4.9#

.071*

.21

.024
.005

.078
.016

49. Okra

Air: 1.5
Other: 1.5

1.3$
.25*

14#
2.8#

.055*

.13

.010
.002

.033
.007

51. Sorghum

Air: 1.5
Other: 1.5

1.2$
.23*

6.4#
1.3#

.031

.073

.010
.002

.033
.007

52. Barley, Cereal Grains, Oats, Rye,
and Wheat

Air: 1.25
Other: 1.25

2.9$
2.2$

18#
11#

23$

117#

.009
.002

.028
.006

53. Gooseberry

Air: 16
Other: 16

15$
3.0$

138#
28#

.001

.005

.11*
.022

.36
.071

154


-------


Maximum

Risk Quotients (RQs) for Freshwater Fish



Malathion





Maloxon



Application

Malathion

Dcgradatc Fraction2

Impurity

Fraction3

Scenario Group: Crop/Site

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

Acute
Peak

Chronic
60-dav

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and
Raspberry (Black - Red)

Air: 4
Other: 4

3.8$
.76$

35#
6.9#

<001

.001

.028
.006

.089
.018

55. Blueberry

Air: 2.5
Other: 2.5

2.9$
.57$

21#
4.3#

.55$

1.9#

.017
.003

.056
.011

56. Caneberries and Currant

Air: 2
Other: 2

1.9$
.38*

17#
3.5#

<001

<001

.014
.003

.045
.009

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

.72$
.14*

13#
2.6#

<001

<001

.005
.001

.017
.003

58. Mint and Spearmint

Air: 1
Other: 1

.85$
.17*

5.9#
1.2#

.49*

1.5#

.007
.001

.022
.004

59. Rice and Wild Rice

Air: 1.5625

Other:

1.5625

351$
351$

1127#
1127#

3.5$

11#

.011
.002

.035
.007

61. Water Cress

Air: 2
Other: 2

449$
449$

1442#
1442#

4.5$

14#

.014
.003

.045
.009





Non-

¦agricultural Uses







Forestry. Christmas Tree
Plantations, Pine (Seed Orchard), and
Slash Pine (Forest)

Air: 3.2
Other: 3.2

14$
13$

67#
48#

143$

518#

.022
.004

.071
.014

Mosquito Control. Intermittently
Flooded Areas/Water,
Lakes/Ponds/Reservoirs (with Human
or Wildlife Use),
Lakes/Ponds/Reservoirs (without
Human or Wildlife Use), Polluted
Water, and

Swamps/MarshesAV etlands/Stagnant
Water

Air: .6
Other: .6

135$
135$

433#
433#

1.3$

4.3#

.004
<001

.013
.003

Nursery. Outdoor Nursery

Air: 2.254
Other: 2.254

2.2$
.43*

20#
4.1#

.49*

1.2#

.016
.003

.050
.010

155


-------


Maximum

Risk Quotients (RQs) for Freshwater Fish



Malathion





Maloxon



Application

Malathion

Dcgradatc Fraction2



Impurity

Fraction3



Rates1

Acute

Chronic

Acute

Chronic



Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

60-dav

Peak

60-dav



Peak

60-dav

Public Health and Medfly Control.

















Nonagricultural Areas (Public Health
Use), Urban Areas, and Wide
Area/General Outdoor Treatment

Air: .6119
Other: .1361

3.7$
.74$

38#
6.3#

79$
17$

632#
140#



.004
<001

.014
<001

(Public Health Use)

















Residential. Household/Domestic

















Dwellings Outdoor Premises,

















Ornamental and/or Shade Trees,

















Ornamental Herbaceous Plants,
Ornamental Lawns and Turf,

Other: ,25s

.046

.98

.032

.10



<001

.001

Ornamental Non-flowering Plants,
Ornamental Woody Shrubs and

















Vines, and Urban Areas

















Rights-of-way. Nonagricultural
Rights-of-way/Fencerows/Hedgerows
and Nonagricultural Uncultivated

Air: .9281
Other: .9281

.74$
.15*

6.4#
1.3#

.003

.010



.006
.001

.021
.004

Areas/Soils

















Turf. Golf Course Turf

Air: 1.25

1.0$

17#

.11*

.34



.009

.028

(Bermudagrass)

Other: 1.25

.20*

3.3#



.002

.006

"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2Maloxon application rate is assumed to be 10.7% of malathion application rate.

3	Maloxon as an impurity in drift is assumed to be 0.1% of malathion in drift.

4	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

5	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

*	Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

#	Chronic RQ >1.0 for listed and non-listed species.

156


-------
For maloxon, the impurity component had to be calculated separately from the degadate
component in PRZM/EXAMS. The maloxon assessment endpoints for freshwater
invertebrates are 0.043 |ig/L (acute) and 1.1 x 10"3 |ig/L (chronic). Maloxon acute RQs
based on the degradate EECs range from 1.0 x 10"5 to 143 for application methods to land
(spray drift assumptions do not apply). Maloxon acute RQs based on the impurity EECS
range from 1.2 x 10"3 to 0.17 for aerial and air-blast application methods to land (5%
spray drift assumed) and 1.9 x 10"4 to 0.038 for other applications to land (1% spray drift
assumed). Maloxon chronic RQs based on the degradate EECS range from 2.5 x 10"5 to
632 for application methods to land. Maloxon chronic RQs based on the impurity EECS
range from 3.9 x 10"3 to 0.56 for aerial and air-blast application methods to land (5%
spray drift assumed) and 6.1 x 10"4 to 0.12 for other applications to land (1% spray drift
assumed). RQs for direct applications to water (spray drift assumptions do not apply)
range from 1.3 to 4.5 (acute) and 4.3 to 14.3 (chronic).

Maloxon EECs, for several uses, yield higher RQs than the respective malathion RQs.
Seventeen of the uses modeled with aerial and air-blast application rates to land have
higher acute maloxon RQs than their respective malathion RQs. Of the 6 uses that have
an 'other' application rates to land that differ from the aerial and air-blast application
rate, 4 uses have higher acute maloxon RQs than their respective malathion RQs. Eleven
of the uses modeled with aerial and air-blast application rates to land have higher chronic
maloxon RQs than their respective malathion RQs. Of the 6 uses that have an 'other'
application rates to land that differ from the aerial and air-blast application rate, 3 uses
had higher chronic maloxon RQs than their respective malathion RQs. None of the acute
or chronic RQs based on the maloxon EECs from the impurity component alone are
greater than the respective malathion RQs.

Freshwater Invertebrates

For malathion, the PRZM/EXAMS EECs includes the drift, runoff, and groundwater
components. For freshwater invertebrates, the assessment endpoints are 0.01 |ig/L (acute)
and 2.6 x 10"5 |ig/L (chronic). Malathion acute RQs range from 65 to 9700 for aerial and
air-blast application methods to land (5% spray drift assumed), 13 to 5000 for other
applications to land (1% spray drift assumed), and 54,000 to 180,000 for direct
applications to water (Table 36). Malathion chronic RQs range from 14,000 to 1,700,000
for aerial and air-blast application methods to land (5% spray drift assumed), 2800 to
470,000 for other applications to land (1% spray drift assumed), and 4,600,000 to
15,000,000 for direct applications to water. All of the uses (aerial and air-blast
application methods to land, other application methods to land, and direct application to
water) exceed both the LOCs for listed (0.1) as well as non-listed (0.5) species.

Malathion EECs would need to be reduced by factors of 14,000 to 1,700,000 for aerial
and air-blast application methods to land, 2700 to 460,000 for other applications to land,
and 4,600,000 to 15,000,000 for applications to water in order to not exceed the listed
species LOC (1) for chronic affects (the most sensitive assessment endpoint for indirect
aquatic phase effects).

157


-------
Table 36. Assessment of indirect effects on the California Red-legged Frog (CRLF) based on effects of malathion (estimate includes drift component)
and maloxon (drift calculated separately) to freshwater Invertebrates.	



Maximum



Risk Quotients (RQs) for

Freshwater Invertebrates





Malathion





Maloxon



Application

Malathion

Dcgradatc Fraction2

Impuritv Fraction3



Rates1

Acute

Chronic

Acute

Chronic

Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

21-dav

Peak

21-dav

Peak

21-dav

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine,
Trefoil, and Vetch

Air: 2
Other: 2

957$
525$

140,827#
59,069#

7530$

724,691#

5.6$
1.1$

478#
96#

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

5189$
1274$

901,577#
210,865#

11,660$

777,637#

42$
8.3$

3583#
717#

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

4265$
857$

673,308#
137,219#

558$

50,945#

35$
7.0$

2986#
597#

4. Chestnut

Air: 5
Other: 5

1649$
331$

281,854#
57,323#

411$

37,543#

14$
2.8$

1194#
239#

5. Almond

Air: 1.25
Other: 4

735$
1333$

132,673#
192,038#

4672$
14,936$

588,557#
1,883,083#

3.5$
2.2$

299#
191#

6. Date

Air: 1

287$

36,066#

127$

11,612#

2.8$

239#

Other: 2

115$

14,494#

254$

23,231#

1.1$

96#

7. Filbert (Hazelnut)

Air: .625
Other: .625

213$
43$

33,663#
6861#

28$

2546#

1.7$
.35*

149#
30#

8. Avocado

Air: 9
Other: 9

3057$
611$

356,088#
71,223#

31$

1943#

25$
5.0$

2150#
430#

9. Citrus, Citrus Hybrids other than
Tangelo, Grapefruit, Kumquat, Lemon,
Lime, Orange, Tangelo, and Tangerines

Air: 25
Other: 25

9720$
1952$

1,742,308#
351,650#

2249$

200,850#

70$
14$

5972#
1194#

10. Amaranth - Chinese, Broccoli















(Unspecified, Chinese, and Raab),
Cabbage (Unspecified and Chinese),
Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel),
Horseradish, Kale, Kohlrabi, Mustard,

Air: 2.5
Other: 2.5

890$
178$

174,442#
34,892#

50$

4039#

7.0$
1.4$

597#
119#

Mustard Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden and
Winter)















158


-------
Maximum

Risk Quotients (RQs) for Freshwater Invertebrates

Malathion



Maloxon

Application

IMalathion

Dcjiradatc Fraction2

Impuritv Fraction3

Scenario Group: Cro|)/Sitc

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

11. Corn (Unspecified, Field, Pop, and
Sweet) and Millet (Foxtail)

Air: 1.5
Other: 1.5

795$
159$

82,054#
16,414#

221$

20,463#

4.2$
.83$

358#
72#

12. Cotton

Air: 4
Other: 4

1999$
522$

487,654#
97,492#

8966$

414,405#

11$
2.2$

955#
191#

15. Apricot

Air: 10
Other: 10

3404$
681$

627,308#
125,496#

.039

2.5#

28$
5.6$

2389#
478#

16. Nectarine and Peach

Air: 9
Other: 9

2934$
587$

508,654#
101,762#

93$

5694#

25$
5.0$

2150#
430#

17. Cherry

Air: 8
Other: 8

2884$
577$

558,192#
111,696#

.037

2.4#

22$
4.5$

1911#
382#

18. Fig

Air: 2.5
Other: 2.5

847$
169$

112,254#
22,447#

2.4$

148#

7.0$
1.4$

597#
119#

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

408$
98$

73,642#
17,671#

24$
28$

1461#
1752#

3.5$
.83$

299#
72#

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

278$
56$

59,069#
11,814#

41$
82$

3429#
6859#

2.1$
.83$

179#
72#

21. Papaya

Air: .175
Other: .175

65$
13$

13,785#
2757#

9.6$

801#

.49*
.097*

42#
8.4#

22. Garlic and Leek

Air: 2
Other: 2

987$
586$

139,500#
52,619#

6543$

418,250#

5.6$
1.1$

478#
96#

23. Grapes

Air: 2.75
Other: 27.47

900$
1798$

95,277#
190,327#

.004
.041

.27
2.7#

7.7$
15$

657#
1312#

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

908$
183$

167,985#
34,147#

4.2$

358#

7.0$
1.4$

597#
119#

27. Swiss Chard, Chervil, Endive
(Escarole), Lettuce, Head Lettuce, Leaf
Lettuce (Black Seeded Simpson, Salad
Bowl, Etc.), Orach (Mountain
Spinach), Parsley, Roquette (Arrugula),
Salsify, and Spinach

Air: 2
Other: 2

1954$
1429$

259,850#
127,150#

32,269$

268,4024#

5.6$
1.1$

478#
96#

159


-------
Maximum

Risk Quotients (RQs) for Freshwater Invertebrates

Malathion



Maloxon

Application

IMalathion

Dcgradatc Fraction2

Impuritv Fraction3

Scenario Group: Cro|)/Sitc

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

28. Peppermint

Air: 1
Other: 1

364$
73$

67,588#
13,800#

.99$

85#

2.8$
.56$

239#
48#

29. Eggplant

Air: 3.5
Other: 3.5

1224$
253$

227,846#
46,004#

2871$

216,382#

9.7$
1.9$

836#
167#

30. Pumpkin

Air: 2
Other: 2

695$
139$

124,996#
25,002#

2040$

132,561#

5.6$
1.1$

478#
96#

31. Cucumber, Cucurbit Vegetables,
Melons - Unspecified, Cantaloupe,
Honey dew, Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persian),
and Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

655$
166$

121,577#
25,500#

2391$

149,397#

5.2$
1.0$

448#
90#

32. Onion (Unspecified and Green),
Radish, and Shallot

Air: 2
Other: 2

787$
320$

155,081#
41,612#

3349$

258,587#

5.6$
1.1$

478#
96#

33. Potato - White/Irish

Air: 3
Other: 3

978$
195$

157,550#
31,514#

2.3$

104#

8.3$
1.7$

717#
143#

34. Turnip

Air: 2.5
Other: 2.5

853$
171$

152,115#
30,427#

.051*

2.4#

7.0$
1.4$

597#
119#

35. Parsnip and Rutabaga

Air: 2
Other: 2

611$
122$

87,158#
17,435#

4.2$

285#

5.6$
1.1$

478#
96#

36. Sweet Potato

Air: 1.875
Other: 1.875

594$
120$

66,458#
13,783#

215$

13,001#

5.2$
1.0$

448#
90#

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland,
Sudangrass, and Timothy

Air: 1.25
Other: 1.25

850$
171$

83,827#
17,320#

9.6$

757#

3.5$
.70$

299#
60#

40. Beets, Cowpea/Blackeyed Pea, and
Peas (Unspecified and Field)

Air: 2.5
Other: 2.5

890$
178$

174,315#
34,863#

.41*

36#

7.0$
1.4$

597#
119#

41. Carrot (Including Tops), Celtuce,
Fennel, and Pepper

Air: 2
Other: 2

834$
167$

193,723#
38,731#

602$

53,426#

5.6$
1.1$

478#
96#

160


-------
Maximum

Risk Quotients (RQs) for Freshwater Invertebrates

Malathion



Maloxon

Application

IMalathion

Dcjiradatc Fraction2

Impuritv Fraction3

Scenario Group: Cro|)/Sitc

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

42. Beans, Beans - Dried-Type, Beans -
Succulent (Lima), and Beans -
Succulent (Snap)

Air: 1.75
Other: 1.75

653$
130$

114,162#
22,833#

21$

1879#

4.9$
.97$

418#
84#

43. Celery

Air: 1.5
Other: 1.5

954$
629$

109,042#
55,730#

8213$

669,302#

4.2$
.83$

358#
72#

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

900$
688$

162,981#
83,231#

9735$

993,351#

3.5$
.70$

299#
60#

45. Anise

Air: .9375
Other: .9375

333$
67$

64,992#
13,002#

437$

38,790#

2.6$
.52$

224#
45#

46. Strawberry

Air: 2
Other: 2

780$
156$

176,877#
35,375#

6.2$

494#

5.6$
1.1$

478#
96#

47. Sugar Beet

Air: 1.875
Other: 1.875

1001$
478$

150,704#
49,719#

7574$

615,177#

5.2$
1.0$

448#
90#

48. Tomato

Air: 3.5
Other: 3.5

1194$
239$

220,123#
44,012#

28$

2139#

9.7$
1.9$

836#
167#

49. Okra

Air: 1.5
Other: 1.5

507$
101$

94,900#
19,043#

22$

1366#

4.2$
.83$

358#
72#

51. Sorghum

Air: 1.5
Other: 1.5

463$
93$

66,412#
13,282#

12$

781#

4.2$
.83$

358#
72#

52. Barley, Cereal Grains, Oats, Rye,
and Wheat

Air: 1.25
Other: 1.25

1152$
869$

170,862#
110,385#

9143$

1,192,229#

3.5$
.70$

299#
60#

53. Gooseberry

Air: 16
Other: 16

6069$
1214$

1,231,462#
246,327#

.58$

54#

45$
8.9$

3822#
764#

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and Raspberry
(Black - Red)

Air: 4
Other: 4

1518$

303$

307,900#
61,573#

.15*

13#

11$
2.2$

955#
191#

55. Blueberry

Air: 2.5
Other: 2.5

1149$
230$

216,154#
43,300#

218$

20,085#

7.0$
1.4$

597#
119#

56. Caneberries and Currant

Air: 2
Other: 2

759$
152$

153,950#
30,790#

.073*

6.7#

5.6$
1.1$

478#
96#

161


-------
Maximum

Risk Quotients (RQs) for Freshwater Invertebrates

Malathion



Maloxon

Application

Malathion

Dc&radatc Fraction2

Impuritv Fraction3

Scenario Group: Cro|)/Sitc

Rates1
(Lbs. ai/A)

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

Acute
Peak

Chronic
21-dav

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

288$
58$

64,246#
12,857#

.10*

9.5#

2.1$
.42*

179#
36#

58. Mint and Spearmint

Air: 1
Other: 1

339$
68$

58,331#
11,666#

194$

16,434#

2.8$
.56$

239#
48#

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

140,400$
140,416$

12,050,824#
12,050,824#

1396$

119,789#

4.3$
.87$

373#
75#

61. Water Cress

Air: 2
Other: 2

179,700$
179,732$

15,425,054#
15,425,054#

1787$

153,330#

5.6$
1.1$

478#
96#

Non-agricultural Uses

Forestry. Christmas Tree Plantations,
Pine (Seed Orchard), and Slash Pine
(Forest)

Air: 3.2
Other: 3.2

5584$
5002$

558,462#
466,658#

57,274$

5,308,878#

8.9$
1.8$

764#
153#

Mosquito Control. Intermittently
Flooded Areas/Water,
Lakes/Ponds/Reservoirs (with Human
or Wildlife Use),
Lakes/Ponds/Reservoirs (without
Human or Wildlife Use), Polluted
Water, and

Swamps/MarshesAV etlands/Stagnant
Water

Air: .6
Other: .6

53,920$
53,920$

4,627,516#
4,627,516#

536$

45,999#

1.7$

.33*

143#
29#

Nursery. Outdoor Nursery

Air: 2.254
Other: 2.254

867$
173$

175,435#
35,227#

196$

12,356#

6.3$
1.3$

537#
107#

Public Health and Medfly Control.

Nonagricultural Areas (Public Health
Use), Urban Areas, and Wide
Area/General Outdoor Treatment
(Public Health Use)

Air: .6119
Other: .1361

1494$
296$

281,596#
54,431#

31,491$
6994$

5,541,128#
1,230,067#

1.7$
.076*

146#
6.5#

162


-------


Maximum



Risk Quotients (RQs) for

Freshwater Invertebrates





Malathion





Maloxon



Application

Malathion

Dcgradatc Fraction2

Impurity

F raction3



Rates1

Acute

Chronic

Acute

Chronic

Acute

Chronic

Scenario Group: Crop/Site

(Lbs. ai/A)

Peak

21-dav

Peak

21-dav

Peak

21-dav

Residential. Household/Domestic















Dwellings Outdoor Premises,















Ornamental and/or Shade Trees,















Ornamental Herbaceous Plants,

Other: ,25s

18$

3755#

13$

1096#

.14*

12#

Ornamental Lawns and Turf,

Ornamental Non-flowering Plants,
Ornamental Woody Shrubs and Vines,















and Urban Areas















Rights-of-way. Nonagricultural Rights-
of-way/Fencerows/Hedgerows and
Nonagricultural Uncultivated

Air: .9281
Other: .9281

296$
59$

47,569#
9517#

1.3$

102#

2.6$
.52$

222#
44#

Areas/Soils















Turf. Golf Course Turf

Air: 1.25

402$

69,023#

42$

3586#

3.5$

299#

(Bermudagrass)

Other: 1.25

80$

13,805#

.70$

60#

"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2Maloxon application rate is assumed to be 10.7% of malathion application rate.

3	Maloxon as an impurity in drift is assumed to be 0.1% of malathion in drift.

4	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

5	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

*	Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

#	Chronic RQ >1.0 for listed and non-listed species.

163


-------
For maloxon, the impurity component had to be calculated separately from the degradate
component using PRZM/EXAMS. The maloxon assessment endpoints for freshwater
invertebrates are 1.1 x 10"4 |ig/L (acute) and 2.8 x 10"7 |ig/L (chronic). Maloxon acute
RQs based on the degradate EECs range from 4.1 x 10"3 to 57,000 for application
methods to land (spray drift assumptions do not apply). Maloxon acute RQs based on the
impurity EECs range from 0.49 to 70 for aerial and air-blast application methods to land
(5% spray drift assumed) and 0.076 to 15 for other applications to land (1% spray drift
assumed). Maloxon chronic RQs based on the degradate EECs range from 0.27 to
5,500,000 for application methods to land. Maloxon chronic RQs based on the impurity
EECs range from 42 to 6000 for aerial and air-blast application methods to land (5%
spray drift assumed) and 6.5 to 1300 for other applications to land (1% spray drift
assumed). RQs for direct applications to water (spray drift assumptions do not apply)
range from 540 to 1800 (acute) and 46,000 to 150,000 (chronic).

A number of maloxon EECs result in higher RQs than the respective malathion RQs.
Seventeen of the uses modeled with aerial and air-blast application rates to land have
higher acute maloxon RQs than their respective malathion RQs. Of the 6 uses that have
an 'other' application rates to land that differ from the aerial and air-blast application
rate, 4 uses have higher acute maloxon RQs than their respective malathion RQs. Eleven
of the uses modeled with aerial and air-blast application rates to land have higher chronic
maloxon RQs than their respective malathion RQs. Of the 6 uses that have an 'other'
application rates to land that differ from the aerial and air-blast application rate, 3 uses
had higher chronic maloxon RQs than their respective malathion RQs. None of the acute
or chronic RQs based on the maloxon EECs from the drift component alone are greater
than the respective malathion RQs.

5.1.2.2 Aquatic Phase Indirect Effects via Reduction in Habitat and/or Primary

Productivity (Freshwater Aquatic Plants)

Risk estimates for aquatic plants with malathion are presented in Table 37. For
unicellular aquatic plants non-listed and listed species effects levels are 2040 and 500
|ig/L, respectively. For vascular plants, an effect endpoint of 24,065 |ig/L was used as a
conservative estimate for both listed and non-listed species evaluation. No RQ values
exceed the non-listed species concern level and only two use scenarios, rice and
watercress produced EECs that trigger listed species concerns and only for unicellular
plants.

Table 37. Assessment of indirect effects to aquatic phase California Red-legged Frog (CRLF) based
on acute risk to aquatic plants and the PRZM/EXAMS estimated environmental concentrations
(EECs) of malathion.			



Maximum

Acute RQs



Application

Unicellular

Unicellular

Vascular

Scenario Group:

Rates1

plants

plants

plants

Crop/Site

(Lbs. ai/A)

EC50

NOEC

NOEC

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine, Trefoil, and

Air: 2

0.005

0.019

<0.001

Vetch

Other: 2

.003

.011

<001

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

.025
.006

.10
.025

.002
<001

164


-------
Maximum

Acute RQs

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Unicellular
plants

EC50

Unicellular
plants

NOEC

Vascular
plants

NOEC

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

.021
.004

.085
.017

.002
<001

4. Chestnut

Air: 5
Other: 5

.008
.002

.033
.007

<001
<001

5. Almond

Air: 1.25
Other: 4

.004
.007

.015
.027

<001
<001

6. Date

Air: 1
Other: 2

.001
<001

.006
.002

<001
<001

7. Filbert (Hazelnut)

Air: .625
Other: .625

.001
<001

.004
<001

<001
<001

8. Avocado

Air: 9
Other: 9

.015
.003

.061
.012

.001
<001

9. Citrus, Citrus Hybrids other than Tangelo,
Grapefruit, Kumquat, Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

.048
.010

.19
.039

.004
<001

10. Amaranth - Chinese, Broccoli (Unspecified,
Chinese, and Raab), Cabbage (Unspecified and
Chinese), Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard Cabbage (Gai
Choy/Pak-Choi), and Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

.004
<001

.018
.004

<001
<001

11. Corn (Unspecified, Field, Pop, and Sweet) and
Millet (Foxtail)

Air: 1.5
Other: 1.5

.004
<001

.016
.003

<001
<001

12. Cotton

Air: 4
Other: 4

.010
.003

.040
.010

<001
<001

15. Apricot

Air: 10
Other: 10

.017
.003

.068
.014

.001
<001

16. Nectarine and Peach

Air: 9
Other: 9

.014
.003

.059
.012

.001
<001

17. Cherry

Air: 8
Other: 8

.014
.003

.058
.012

.001
<001

18. Fig

Air: 2.5
Other: 2.5

.004
<001

.017
.003

<001
<001

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

.002
<001

.008
.002

<001
<001

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

.001
<001

.006
.001

<001
<001

21. Papaya

Air: .175
Other: .175

<001
<001

.001
<001

<001
<001

22. Garlic and Leek

Air: 2
Other: 2

.005
.003

.020
.012

<001
<001

23. Grapes

Air: 2.75
Other: 27.47

.004
.009

.018
.036

<001
<001

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

.004
<001

.018
.004

<001
<001

27. Swiss Chard, Chervil, Endive (Escarole),
Lettuce, Head Lettuce, Leaf Lettuce (Black
Seeded Simpson, Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley, Roquette (Arrugula),
Salsify, and Spinach

Air: 2
Other: 2

.010
.007

.039
.029

<001
<001

165


-------
Maximum

Acute RQs

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Unicellular
plants

EC50

Unicellular
plants

NOEC

Vascular
plants

NOEC

28. Peppermint

Air: 1
Other: 1

.002
<001

.007
.001

<001
<001

29. Eggplant

Air: 3.5
Other: 3.5

.006
.001

.024
.005

<001
<001

30. Pumpkin

Air: 2
Other: 2

.003
<001

.014
.003

<001
<001

31. Cucumber, Cucurbit Vegetables, Melons -
Unspecified, Cantaloupe, Honeydew, Musk,
Water, and Winter

(Casaba/Crenshaw/Honeydew/Persian), and
Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

.003
<001

.013
.003

<001
<001

32. Onion (Unspecified and Green), Radish, and
Shallot

Air: 2
Other: 2

.004
.002

.016
.006

<001
<001

33. Potato - White/Irish

Air: 3
Other: 3

.005
<001

.020
.004

<001
<001

34. Turnip

Air: 2.5
Other: 2.5

.004
<001

.017
.003

<001
<001

35. Parsnip and Rutabaga

Air: 2
Other: 2

.003
<001

.012
.002

<001
<001

36. Sweet Potato

Air: 1.875
Other: 1.875

.003
<001

.012
.002

<001
<001

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas (Including
Vines), Rangeland, Sudangrass, and Timothy

Air: 1.25
Other: 1.25

.004
<001

.017
.003

<001
<001

40. Beets, Cowpea/Blackeyed Pea, and Peas
(Unspecified and Field)

Air: 2.5
Other: 2.5

.004
<001

.018
.004

<001
<001

41. Carrot (Including Tops), Celtuce, Fennel, and
Pepper

Air: 2
Other: 2

.004
<001

.017
.003

<001
<001

42. Beans, Beans - Dried-Type, Beans - Succulent
(Lima), and Beans - Succulent (Snap)

Air: 1.75
Other: 1.75

.003
<001

.013
.003

<001
<001

43. Celery

Air: 1.5
Other: 1.5

.005
.003

.019
.013

<001
<001

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

.004
.003

.018
.014

<001
<001

45. Anise

Air: .9375
Other: .9375

.002
<001

.007
.001

<001
<001

46. Strawberry

Air: 2
Other: 2

.004
<001

.016
.003

<001
<001

47. Sugar Beet

Air: 1.875
Other: 1.875

.005
.002

.020
.010

<001
<001

48. Tomato

Air: 3.5
Other: 3.5

.006
.001

.024
.005

<001
<001

49. Okra

Air: 1.5
Other: 1.5

.002
<001

.010
.002

<001
<001

51. Sorghum

Air: 1.5
Other: 1.5

.002
<001

.009
.002

<001
<001

52. Barley, Cereal Grains, Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

.006
.004

.023
.017

<001
<001

53. Gooseberry

Air: 16
Other: 16

.030
.006

.12
.024

.003
<001

166


-------
Maximum

Acute RQs

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Unicellular
plants

EC50

Unicellular
plants

NOEC

Vascular
plants

NOEC

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

.007
.001

.03
.006

<001
<001

55. Blueberry

Air: 2.5
Other: 2.5

.006
.001

.023
.005

<001
<001

56. Caneberries and Currant

Air: 2
Other: 2

.004
<001

.015
.003

<001
<001

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

.001
<001

.006
.001

<001
<001

58. Mint and Spearmint

Air: 1
Other: 1

.002
<001

.007
.001

<001
<001

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

.69
.69

2.8*
2.8*

.058
.058

61. Water Cress

Air: 2
Other: 2

.88
.88

3.6*
3.6*

.075
.075

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine (Seed
Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

.027
.025

.11
.10

.002
.002

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs (with
Human or Wildlife Use), Lakes/Ponds/Reservoirs
(without Human or Wildlife Use), Polluted Water,
and Swamps/Marshes/Wetlands/Stagnant Water

Air: .6
Other: .6

.26
.26

1.1*
1.1*

.022
.022

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

.004
<001

.017
.003

<001
<001

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use), Urban
Areas, and Wide Area/General Outdoor Treatment
(Public Health Use)

Air: .6119
Other: .1361

.007
.001

.030
.006

<001
<001

Residential. Household/Domestic Dwellings
Outdoor Premises, Ornamental and/or Shade
Trees, Ornamental Herbaceous Plants, Ornamental
Lawns and Turf, Ornamental Non-flowering
Plants, Ornamental Woody Shrubs and Vines, and
Urban Areas

Other: ,253

<001

<001

<001

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

.001
<001

.006
.001

<001
<001

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

.002
<001

.008
.002

<001
<001

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift
when estimating environmental concentrations. "Other" refers other application methods for which EFED
policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from
2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does
not assume the same parcels are re-treated each weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25
lbs. ai/A.

* Acute RQ > 0.1 for listed species.

167


-------
For maloxon, no effects endpoints were identified for unicellular or vascular plants.

Based on the high degree of structural similarity of malathion and maloxon, and no likely
specific mechanism of action unique to plants, it was assumed that maloxon toxicity
would not likely be greater than malathion. Given the higher exposures associated with
parent malathion, it was concluded that maloxon risks were likely to be trivial in relation
to malathion.

5.1.2.3 Aquatic Phase Indirect Effects via Reduction in Terrestrial Plant

Community (Riparian Habitat)

The risk assessment process relies predominantly on effects endpoints associated with
seedling emergence, growth, and plant viability. There are no submitted registrant data
for malathion and terrestrial plants. A review of the available ECOTOX data, meeting
OPP data quality criteria, did not show any effects on emergence, growth, and plant
viability for any dicot plants species under any application conditions. EFED concludes
malathion applications consistent with the current label are likely to have no indirect
effect on the CRLF via Reduction in Terrestrial Plant Community (Riparian Habitat)
(Table 1).

5.1.3 Terrestrial Phase Direct Effects

Table 38 presents acute RQ values for direct effects of malathion on terrestrial phases of
the CRLF. The evaluation in Table 38 uses dietary concentration-based and dose-based
risk calculations and uses avian effects data and consumption models as a surrogate for
terrestrial amphibians. RQs calculations are based on EECs from the T-Rex model for a
20g bird and the appropriate effects endpoints. The assessment endpoints are 167 mg/kg-
bw (ring-necked Pheasant LD50), 2128 mg/kg-diet (Japanese quail LC50), and 110 mg/kg-
diet (bobwhite quail NOAEC) for birds and 3400 mg/kg-bw (LD50), 240 mg/kg-bw
(NOAEL), and 4000 mg/kg-diet (NOAEC) for mammals. In situations where risks
concerns are triggered by this method, refinement of the risk picture, based on more
amphibian appropriate consumption models may be undertaken as part of the risk
characterization.

168


-------
Table 38. Assessment of indirect effects on the terrestrial phase of the California Red-legged Frog (CRLF based on dietary- and dose-based risk
quotients (RQs) for small (20 g) birds (a prey item of the CRLF).		





Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Agricultural Uses

1. Alfalfa, Clover, Lespedeza,
Lupine, Trefoil, and Vetch

Air: 2
Other: 2

0.32*/6.17#

0.15*/2.83#

0.18*/3.47#

0.02/0.39

8.48$

3.89$

4.77$

0.53$

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

2.88$/55.7#

1.32$/25.5#

1.62$/31.3#

.18*/3.48#

76.6$

35.1$

43.1$

4.79$

3. Pecan and Walnut
(English/Black)

Air: 12.5
Other: 12.5

2.38$ / 46.1#

1.09$ / 21.1#

1.34$/25.9#

.15*/2.88#

63.4$

29.0$

35.6$

3.96$

4. Chestnut

Air: 5
Other: 5

.93$/ 18.1#

.43*/8.28#

.53$/ 10.2#

.06/1.13#

24.8$

11.4$

14.0$

1.55$

5. Almond

Air: 1.25
Other: 4

.24*/4.61#
.76$ / 14.7#

.11* / 2.11#
.35*/6.76#

.13* / 2.59#
.43*/8.30#

.01/.29
.05 / .92

6.34$
20.3$

2.90$
9.29$

3.56$
11.4$

.40*
1.27$

6. Date

Air: 1
Other: 2

.14*/2.62#
.27* / 5.24#

.06/ 1.20#
.12*/2.40#

.08/ 1.47#
.15*/2.95#

.01/.16
.02/.33

3.60$
7.20$

1.65$
3.30$

2.03$
4.05$

.23*
.45*

7. Filbert (Hazelnut)

Air: .625
Other: .625

.12*/2.30#

.05/ 1.06#

.07/ 1.30#

.01/.14

3.17$

1.45$

1.78$

.20*

8. Avocado

Air: 9
Other: 9

1.49$/28.9#

.68$/ 13.2#

.84$/ 16.2#

.09/ 1.80#

39.7$

18.2$

22.3$

2.48$

9. Citrus, Citrus Hybrids other
than Tangelo, Grapefruit,
Kumquat, Lemon, Lime,
Orange, Tangelo, and
Tangerines

Air: 25
Other: 25

4.76$ / 92.2#

2.18$/42.2#

2.68$/51.8#

.30*/5.76#

127$

58.1$

71.3$

7.92$

169


-------




Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

10. Amaranth - Chinese,
Broccoli (Unspecified,
Chinese, and Raab), Cabbage
(Unspecified and Chinese),
Canola\Rape, Cauliflower,
Collards, Corn Salad, Dock
(Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard
Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden
and Winter)

Air: 2.5
Other: 2.5

.48* / 9.26#

.22*/4.24#

.27*/5.21#

.03/.58

12.7$

5.83$

7.16$

.80$

11. Corn (Unspecified, Field,
Pop, and Sweet) and Millet
(Foxtail)

Air: 1.5
Other: 1.5

.40*/7.79#

.18*/3.57#

.23*/4.38#

.03 / .49

10.7$

4.91$

6.03$

.67$

12. Cotton

Air: 4
Other: 4

1.43$/27.7#

.66$ / 12.7#

.81$/ 15.6#

.09/ 1.73#

38.1$

17.5$

21.4$

2.38$

15. Apricot

Air: 10
Other: 10

2.02$/39.1#

.93$/ 17.9#

1.14$/22.0#

.13*/2.45#

53.8$

24.7$

30.3$

3.36$

16. Nectarine and Peach

Air: 9
Other: 9

1.82$/35.2#

.83$/ 16.1#

1.02$/ 19.8#

.11*/2.20#

48.4$

22.2$

27.2$

3.03$

17. Cherry

Air: 8
Other: 8

1.68$/32.5#

.77$/ 14.9#

.95$/ 18.3#

.11* / 2.03#

44.7$

20.5$

25.2$

2.80$

18. Fig

Air: 2.5
Other: 2.5

.51$/9.91#

.23*/4.54#

.29*/5.57#

.03 / .62

13.6$

6.24$

7.66$

.85$

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

.27*/5.14#
.32*/6.17#

.12*/2.35#
.15* / 2.83#

.15*/2.89#
.18*/3.47#

.02/.32
.02/.39

7.06$
8.48$

3.24$
3.89$

3.97$
4.77$

.44*
.53$

20. Guava, Mango, Plum, and
Prune

Air: .75
Other: 1.5

.16*/3.08#
.32*/6.17#

.07/1.41#
.15* / 2.83#

.09/ 1.73#
.18*/3.47#

.01/.19
.02/.39

4.24$
8.48$

1.94$
3.89$

2.39$
4.77$

.27*
.53$

21. Papaya

Air: .175
Other: .175

.04 / .72

.02/.33

.02 / .40

<01/.04

.99$

.45*

.56$

.06

170


-------


Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

22. Garlic and Leek

Air: 2
Other: 2

.38*/7.35#

.17*/3.37#

.21*/4.14#

.02 / .46

10.1$

4.63$

5.69$

.63$

23. Grapes

Air: 2.75
Other: 27.47

.46* / 8.82#
4.55$/88.1#

.21*/4.04#
2.09$/40.4#

.26*/4.96#
2.56$/49.5#

.03/.55
.28*/5.50#

12.1$
121$

5.56$
55.5$

6.82$
68.1$

.76$
7.57$

26. Brussel Sprouts and
Dandelion

Air: 2.5
Other: 2.5

.45*/8.65#

.20*/3.96#

.25*/4.86#

.03 / .54

11.9$

5.45$

6.69$

.74$

27. Swiss Chard, Chervil,
Endive (Escarole), Lettuce,
Head Lettuce, Leaf Lettuce
(Black Seeded Simpson,
Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley,
Roquette (Arrugula), Salsify,
and Spinach

Air: 2
Other: 2

.47*/9.12#

.22*/4.18#

.27*/5.13#

.03 / .57

12.5$

5.75$

7.05$

.78$

28. Peppermint

Air: 1
Other: 1

.18*/3.46#

.08/ 1.59#

.10*/1.95#

.01/0.22

4.76$

2.18$

2.67$

.30*

29. Eggplant

Air: 3.5
Other: 3.5

.81$/ 15.6#

.37*/7.17#

.45*/8.80#

.05 / .98

21.5$

9.85$

12.1$

1.34$

30. Pumpkin

Air: 2
Other: 2

.42*/8.14#

.19*/3.73#

.24*/4.58#

.03/.51

11.2$

5.13$

6.29$

.70$

31. Cucumber, Cucurbit
Vegetables, Melons -
Unspecified, Cantaloupe,
Honeydew, Musk, Water, and
Winter

(Casaba/Crenshaw/Honeydew
/Persian), and Squash (All Or
Unspecified)

Air: 1.875
Other: 1.875

.39*/7.63#

.18*/3.50#

.22*/4.29#

.02 / .48

10.5$

4.81$

5.90$

.66$

32. Onion (Unspecified and
Green), Radish, and Shallot

Air: 2
Other: 2

.38*/7.35#

.17*/3.37#

.21*/4.14#

.02 / .46

10.1$

4.63$

5.69$

.63$

33. Potato - White/Irish

Air: 3
Other: 3

.57$/ 11.0#

.26* / 5.06#

.32*/6.21#

.04 / .69

15.2$

6.95$

8.53$

.95$

171


-------




Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs



Maximum













Broadlcaf

Fruit/



Application





Broad leaf

Fruit/ Pods/





Plants/

Pods/Seeds/

Scenario Group:

Rates1

Short

Tall

Plants/Small

Seeds/Large

Short

Tall

Small

Large

Crop/Site

(Lbs. ai/A)

Grass

Grass

Insects

Insects

Grass

Grass

Insects

Insects

34. Turnip

Air: 2.5
Other: 2.5

.48*/9.19#

.22*/4.21#

.27*/5.17#

.03 / .57

12.6$

5.79$

7.11$

.79$

35. Parsnip and Rutabaga

Air: 2
Other: 2

.38*/7.35#

.17*/3.37#

.21*/4.14#

.02 / .46

10.1$

4.63$

5.69$

.63$

36. Sweet Potato

Air: 1.875
Other: 1.875

.30*/5.78#

.14*/2.65#

.17*/3.25#

.02/.36

7.95$

3.64$

4.47$

.50$

37. Bluegrass, Canarygrass,
Grass Forage/Fodder/Hay,
Pastures, Peas (Including

Air: 1.25
Other: 1.25

.37*/7.25#

.17*/3.32#

.21*/4.08#

.02 / .45

9.97$

4.57$

5.61$

.62$

Vines), Rangeland,
Sudangrass, and Timothy

















40. Beets, Cowpea/Blackeyed
Pea, and Peas (Unspecified

Air: 2.5
Other: 2.5

.48*/9.19#

.22*/4.21#

.27*/5.17#

.03 / .57

12.6$

5.79$

7.11$

.79$

and Field)

















41. Carrot (Including Tops),
Celtuce, Fennel, and Pepper

Air: 2
Other: 2

.48* / 9.22#

.22*/4.23#

.27*/5.19#

.03/.58

12.7$

5.81$

7.13$

.79$

42. Beans, Beans - Dried-



















Type, Beans - Succulent
(Lima), and Beans -

Air: 1.75
Other: 1.75

.33*/6.45#

.15*/2.96#

.19*/3.63#

.02 / .40

8.87$

4.07$

4.99$

.55$

Succulent (Snap)



















43. Celery

Air: 1.5
Other: 1.5

.24*/4.63#

.11* / 2.12#

.13*/2.60#

.01/.29

6.36$

2.92$

3.58$

.40*

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

.24*/4.65#

.11* / 2.13#

.14*/2.62#

.02 / .29

6.40$

2.93$

3.60$

.40*

45. Anise

Air: .9375
Other: .9375

.18*/3.48#

.08/ 1.60#

.10*/1.96#

.01/.22

4.79$

2.19$

2.69$

.30*

46. Strawberry

Air: 2
Other: 2

.42*/8.14#

.19*/3.73#

.24*/4.58#

.03/.51

11.2$

5.13$

6.29$

.70$

47. Sugar Beet

Air: 1.875
Other: 1.875

.36*/6.89#

.16*/3.16#

.20*/3.88#

.02 / .43

9.48$

4.34$

5.33$

.59$

172


-------


Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

48. Tomato

Air: 3.5
Other: 3.5

.81$/ 15.6#

.37*/7.17#

.45*/8.80#

.05 / .98

21.5$

9.85$

12.1$

1.34$

49. Okra

Air: 1.5
Other: 1.5

.32*/6.10#

.14*/2.80#

.18*/3.43#

.02/.38

8.39$

3.85$

4.72$

.52$

51. Sorghum

Air: 1.5
Other: 1.5

.27*/5.19#

.12*/2.38#

.15*/2.92#

.02/.32

7.13$

3.27$

4.01$

.45*

52. Barley, Cereal Grains,
Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

.22*/4.32#

.10*/1.98#

.13*/2.43#

.01/.27

5.94$

2.72$

3.34$

.37*

53. Gooseberry

Air: 16
Other: 16

3.24$/62.6#

1.48$/28.7#

1.82$/35.2#

.20*/3.91#

86.1$

39.4$

48.4$

5.38$

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and
Raspberry (Black - Red)

Air: 4
Other: 4

.81$/ 15.7#

.37*/7.17#

.46* / 8.80#

.05 / .98

21.5$

9.86$

12.1$

1.34$

55. Blueberry

Air: 2.5
Other: 2.5

.62$/ 11.9#

.28* / 5.47#

.35*/6.72#

.04 / .75

16.4$

7.52$

9.24$

1.03$

56. Caneberries and Currant

Air: 2
Other: 2

.40*/7.83#

.19*/3.59#

.23*/4.40#

.03 / .49

10.8$

4.93$

6.05$

.67$

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

.16*/3.08#

.07/1.41#

.09/ 1.73#

.01/.19

4.23$

1.94$

2.38$

.26*

58. Mint and Spearmint

Air: 1
Other: 1

.18*/3.46#

.08/ 1.59#

.10*/1.95#

.01/0.22

4.76$

2.18$

2.67$

.30*

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

.28*/5.40#

.13*/2.48#

.16*/3.04#

.02/.34

7.43$

3.41$

4.18$

.46*

61. Water Cress

Air: 2
Other: 2

.46*/8.93#

.21*/4.10#

.26*/5.03#

.03 / .56

12.3$

5.63$

6.91$

.77$

Non-agricultural Uses

Forestry. Christmas Tree
Plantations, Pine (Seed
Orchard), and Slash Pine
(Forest)

Air: 3.2
Other: 3.2

.49*/9.52#

.23*/4.36#

.28*/5.36#

.03 / .60

13.1$

6.00$

7.36$

.82$

173


-------


Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Mosquito Control.

Intermittently Flooded
Areas/Water,

Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs
(without Human or Wildlife
Use), Polluted Water, and
Swamps/MarshesAV etlands/S
tagnant Water

Air: .6
Other: .6

.09/ 1.82#

.04 / .84

.05/ 1.03#

.01/.11

2.51$

1.15$

1.41$

.16*

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

.52$/ 10.1#

.24*/4.61#

.29* / 5.66#

.03 / .63

13.8$

6.34$

7.78$

.86$

Public Health and Medfly
Control. Nonagricultural
Areas (Public Health Use),
Urban Areas, and Wide
Area/General Outdoor
Treatment (Public Health
Use)

Air: .6119
Other: .1361

.12*/2.28#
.03 / .51

.05/ 1.04#
.01/.23

.07/ 1.28#
.01/.28

.01/.14
<01/.03

3.13$
.70$

1.44$
.32*

1.76$
.39*

.20*
.04

Residential.

Household/Domestic
Dwellings Outdoor Premises,
Ornamental and/or Shade
Trees, Ornamental
Herbaceous Plants,
Ornamental Lawns and Turf,
Ornamental Non-flowering
Plants, Ornamental Woody
Shrubs and Vines, and Urban
Areas

Other: ,253

.05 / .94

.02 / .43

.03/.53

<01/.06

1.29$

.59$

.73$

.08

174


-------




Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs



Maximum













Broadlcaf

Fruit/



Application





Broad leaf

Fruit/ Pods/





Plants/

Pods/Seeds/

Scenario Group:

Rates1

Short

Tall

Plants/Small

Seeds/Large

Short

Tall

Small

Large

Crop/Site

(Lbs. ai/A)

Grass

Grass

Insects

Insects

Grass

Grass

Insects

Insects

Rights-of-way.

Nonagricultural Rights-of-
way/Fencerows/Hedgerows
and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

.14*/2.76#

.07/ 1.27#

.08/ 1.55#

.01/.17

3.80$

1.74$

2.14$

.24*

Turf. Golf Course Turf
(Bermudagrass)

Air: 1.25
Other: 1.25

.20*/3.80#

.09/ 1.74#

.11* / 2.14#

.01/.24

5.23$

2.40$

2.94$

.33*

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

*	Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

#	Chronic RQ >1.0 for listed and non-listed species.

175


-------
Risk calculations based on consumption of amphibian prey within application areas do
not result in acute concerns, and only result in chronic concerns for 4 of 68 use scenarios
(macadamia nuts, citrus, grapes, and gooseberries). Consumption of small insectivorous
mammal prey within application areas triggers acute listed species and chronic concerns
in 5 of 68 use scenarios (macadamia nuts, pecan/walnuts, citrus, grapes, and
gooseberries), yet no RQs exceed the non-listed species acute LOC. Higher RQ results
can be seen with consumption of small herbivorous mammals, where prey body burdens
of malathion trigger acute listed species concerns in 53 use scenarios, acute non-listed
concerns in 14 use scenarios, and chronic concerns in all 68 use scenarios. With large
insects as a food source, RQ values exceed the non-listed species acute concern level for
8 use scenarios (macadamia nuts, pecan/walnuts, citrus, apricots, nectarine/peaches,
cherries, grapes, and gooseberries) and exceed the chronic concern level for 11 use
scenarios (macadamia nuts, pecan/walnuts, chestnuts, avocados, cotton, citrus, apricots,
nectarine/peaches, cherries, grapes, and gooseberries). Small insect food residues are high
enough to trigger acute listed species concerns in 54 use scenarios, acute non-listed
species concern levels in 11 use scenarios (macadamia nuts, pecan/walnuts, chestnuts,
avocados, cotton, citrus, apricots, nectarine/peaches, cherries, grapes, and gooseberries).
Chronic concerns are triggered for residues in small insects for all but 2 scenarios
(residential yard lawn and ornamental use and the papaya use).

Based on the highest terrestrial direct effect RQs, all of the uses modeled with aerial and
air-blast application methods to land and all of the uses with direct application to water
exceed both the LOCs for listed (0.1) as well as non-listed (0.5) species. All of the uses
modeled with other application methods to land exceed both the LOCs for listed (0.1) as
well as non-listed (0.5) species, except residential (RQ = 0.31) and papaya (RQ = 0.22)
uses, which only exceeded the LOC for listed species. Malathion EECs would need to be
reduced by factors of 11 to 1600 for aerial and air-blast application methods to land, 2.2
to 850 for other applications to land, and 9100 to 30,000 for applications to water in order
to not exceed the listed species LOC (0.1) for acute affects (the most sensitive assessment
endpoint for direct aquatic phase effects).

5.1.4 Terrestrial Phase Indirect and Effects

Potentially, indirect effects on the aquatic phase of the CRLF include toxic effects on
prey items including mammals, birds, and invertebrates. Terrestrial plant effects may
indirectly result in alterations in habitat, which could limit sheltering opportunities. The
following sections present the results of RQ evaluations for mammal, bird, invertebrate,
and terrestrial plant taxonomic groups.

5.1.4.1 Terrestrial Phase Indirect Effects via Reduction in Food Items
Mammal Prey

Mammalian prey effects for terrestrial phase CRLF were assessed using the RQ estimates
for small 15 g mammals (Table 39). When exposure were estimated on a dietary basis
and compared to a chronic effects endpoint in the same units, only 2 use scenarios
triggered concerns (macadamia nuts and pecan/walnuts) and only for an herbivorous

176


-------
small mammal consuming short grasses. Granivorous mammal RQs in this size category
do not trigger any acute or chronic effects concerns for any use scenario modeled when
risk are evaluated on a dose-based approach. Herbivorous/insectivorous small mammal
prey categories exhibit dose-based RQ values exceeding chronic concerns in 45 of 68 use
scenarios, and most of the exceeding RQs are limited to short grass, tall grass, and
broadleaf plant/small insect residues categories.

177


-------
Table 39. Assessment of indirect effects on the terrestrial phase of the California Red-legged Frog (CRLF based on dietary- and dose-based risk
quotients (RQs) for small (15 g) mammals (a prey item of the CRLF).		





Dictarv-bascd Chronic RQs

Dose-based RQs (Acute / Chronic)











Fruit/

Herbivores and Insectivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadlcat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

Agricultural Uses

1. Alfalfa, Clover, Lespedeza,
Lupine, Trefoil, and Vetch

Air: 2
Other: 2

0.17

0.08

0.10

0.01

0.09/ 1.23#

0.04/0.56

0.05/0.69

0.01/0.08

<01/0.02

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

1.53#

.70

.86

.10

.78$/ 11.1#

.36*/5.08#

.44*/6.23#

.05 / .69

.01 / .15

3. Pecan and Walnut
(English/Black)

Air: 12.5
Other: 12.5

1.27#

.58

.71

.08

.65$/9.16#

.30*/4.2#

.36*/5.15#

.04 / .57

.01 / .13

4. Chestnut

Air: 5
Other: 5

.50

.23

.28

.03

.25*/3.59#

.12*/ 1.65#

.14*/2.02#

.02 / .22

< 01 / .05

5. Almond

Air: 1.25
Other: 4

.13
.41

.06
.19

.07
.23

.01
.03

.06 / .92
.21*/2.93#

.03 / .42
.09/ 1.34#

.04 / .52
.12*/1.65#

<01/.06
.01/.18

<01 / .01
<01/.04

6. Date

Air: 1
Other: 2

.07
.14

.03
.07

.04
.08

<01
.01

.04 / .52
.07/ 1.04#

.02 / .24
.03 / .48

.02 / .29
.04/.59

<01/.03
<01/.07

<01 / .01
<01 / .01

7. Filbert (Hazelnut)

Air: .625
Other: .625

.06

.03

.04

<01

.03 / .46

.01 / .21

.02 / .26

<01/.03

<01 / .01

8. Avocado

Air: 9
Other: 9

.79

.36

.45

.05

.40* / 5.74#

.19*/2.63#

.23*/3.23#

.03/.36

.01 / .08

9. Citrus, Citrus Hybrids other
than Tangelo, Grapefruit,
Kumquat, Lemon, Lime,
Orange, Tangelo, and
Tangerines

Air: 25
Other: 25

2.53

1.16

1.43

.16

1.29$/18.3#

.59$/8.4#

.73$/ 10.3#

.08/1.15#

.02 / .25

178


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Dictarv-bascd Chronic RQs

Dose-based RQs (Acute/ Chronic)











Fruit/

Herbivores and Inscctivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadlcat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

10. Amaranth - Chinese,
Broccoli (Unspecified,
Chinese, and Raab), Cabbage
(Unspecified and Chinese),
CanolaVRape, Cauliflower,
Collards, Corn Salad, Dock
(Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard
Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden
and Winter)

Air: 2.5
Other: 2.5

.25

.12

.14

.02

.13*/ 1.84#

.06 / .84

.07/ 1.04#

.01/.12

< 01 / .03

11. Corn (Unspecified, Field,
Pop, and Sweet) and Millet
(Foxtail)

Air: 1.5
Other: 1.5

.21

.10

.12

.01

.11*/ 1.55#

.05/.71

.06 / .87

.01/.10

<01/.02

12. Cotton

Air: 4
Other: 4

.76

.35

.43

.05

.39*/5.51#

.18* / 2.53#

.22*/3.1#

.02/.34

.01 / .08

15. Apricot

Air: 10
Other: 10

1.08

.49

.61

.07

.55$/7.78#

.25*/3.57#

.31* / 4.38#

.03 / .49

.01 /.ll

16. Nectarine and Peach

Air: 9
Other: 9

.97

.44

.54

.06

.49*/7.0#

.23*/3.21#

.28*/3.94#

.03 / .44

.01 / .10

17. Cherry

Air: 8
Other: 8

.90

.41

.50

.06

.46*/6.47#

.21*/2.97#

.26*/3.64#

.03 / .40

.01 / .09

18. Fig

Air: 2.5
Other: 2.5

.27

.12

.15

.02

.14*/ 1.97#

.06 / .90

.08/1.11#

.01/.12

< 01 / .03

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

.14
.17

.06
.08

.08
.10

.01
.01

.07/ 1.02#
.09/ 1.23#

.03 / .47
.04 / .56

.04 / .57
.05 / .69

<01/.06
.01/.08

<01 / .01
<01/.02

20. Guava, Mango, Plum, and
Prune

Air: .75
Other: 1.5

.08
.17

.04
.08

.05
.10

.01
.01

.04/.61
.09/ 1.23#

.02 / .28
.04 / .56

.02/.34
.05 / .69

<01/.04
.01/.08

<01 / .01
<01/.02

21. Papaya

Air: .175
Other: .175

.02

.01

.01

<01

.01 / .14

<01 / .07

.01/.08

<01/. 01

<01 / <01

179


-------




Dictarv-bascd Chronic RQs

Dose-based RQs (Acute/ Chronic)











Fruit/

Herbivores and Inscctivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadlcat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

22. Garlic and Leek

Air: 2
Other: 2

.20

.09

.11

.01

.10*/ 1.46#

.05 / .67

.06 / .82

.01/.09

<01/.02

23. Grapes

Air: 2.75
Other: 27.47

.24
2.42

.11
1.11

.14
1.36

.02
.15

.12*/ 1.75#
1.24$/ 17.5#

.06 / .80
.57$/8.03#

.07 / .99
.70$/9.85#

.01/.11
.08/1.09#

<01/.02
.02 / .24

26. Brussel Sprouts and
Dandelion

Air: 2.5
Other: 2.5

.24

.11

.13

.01

.12*/ 1.72#

.06 / .79

.07 / .97

.01/.11

<01/.02

27. Swiss Chard, Chervil,
Endive (Escarole), Lettuce,
Head Lettuce, Leaf Lettuce
(Black Seeded Simpson,
Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley,
Roquette (Arrugula), Salsify,
and Spinach

Air: 2
Other: 2

.25

.11

.14

.02

.13*/ 1.81#

.06 / .83

.07/ 1.02#

.01/.11

< 01 / .03

28. Peppermint

Air: 1
Other: 1

.10

.04

.05

.01

.05 / .69

.02 / .32

.03/.39

<01/.04

<01 / .01

29. Eggplant

Air: 3.5
Other: 3.5

.43

.20

.24

.03

.22*/3.11#

.10*/ 1.42#

.12*/1.75#

.01/.19

<01/.04

30. Pumpkin

Air: 2
Other: 2

.22

.10

.13

.01

.11*/ 1.62#

.05 / .74

.06/.91

.01/.10

<01/.02

31. Cucumber, Cucurbit
Vegetables, Melons -
Unspecified, Cantaloupe,
Honey dew, Musk, Water, and
Winter

(Casaba/Crenshaw/Honeydew
/Persian), and Squash (All Or
Unspecified)

Air: 1.875
Other: 1.875

.21

.10

.12

.01

.11*/ 1.52#

.05 / .70

.06 / .85

.01/.09

<01/.02

32. Onion (Unspecified and
Green), Radish, and Shallot

Air: 2
Other: 2

.20

.09

.11

.01

.10*/ 1.46#

.05 / .67

.06 / .82

.01/.09

<01/.02

180


-------




Dictarv-bascd Chronic RQs

Dose-based RQs (Acute/ Chronic)











Fruit/

Herbivores and Inscctivorcs

Granivorcs



Maximum





Broadlcat

Pods/





Broad leaf

Fruit/





Application





Plants/

Seeds/





Plants/

Pods/Seeds/



Scenario Group:

Rates1

Short

Tall

Small

Large

Short

Tall

Small

Large



Crop/Site

(Lbs. ai/A)

Grass

Grass

Insects

Insects

Grass

Grass

Insects

Insects

Seeds

33. Potato - White/Irish

Air: 3
Other: 3

.30

.14

.17

.02

.15* / 2.19#

.07/1.01#

.09/ 1.23#

.01/.14

< 01 / .03

34. Turnip

Air: 2.5
Other: 2.5

.25

.12

.14

.02

.13*/ 1.83#

.06 / .84

.07/ 1.03#

.01/.11

< 01 / .03

35. Parsnip and Rutabaga

Air: 2
Other: 2

.20

.09

.11

.01

.10*/ 1.46#

.05 / .67

.06 / .82

.01/.09

<01/.02

36. Sweet Potato

Air: 1.875
Other: 1.875

.16

.07

.09

.01

.08/1.15#

.04 / .53

.05 / .65

.01/.07

<01/.02

37. Bluegrass, Canarygrass,
Grass Forage/Fodder/Hay,
Pastures, Peas (Including

Air: 1.25
Other: 1.25

.20

.09

.11

.01

.10*/ 1.44#

.05 / .66

.06/.81

.01/.09

<01/.02

Vines), Rangeland,
Sudangrass, and Timothy



















40. Beets, Cowpea/Blackeyed
Pea, and Peas (Unspecified

Air: 2.5
Other: 2.5

.25

.12

.14

.02

.13*/ 1.83#

.06 / .84

.07/ 1.03#

.01/.11

< 01 / .03

and Field)



















41. Carrot (Including Tops),
Celtuce, Fennel, and Pepper

Air: 2
Other: 2

.25

.12

.14

.02

.13*/ 1.83#

.06 / .84

.07/ 1.03#

.01/.11

< 01 / .03

42. Beans, Beans - Dried-





















Type, Beans - Succulent
(Lima), and Beans - Succulent

Air: 1.75
Other: 1.75

.18

.08

.10

.01

.09/ 1.28#

.04 / .59

.05 / .72

.01/.08

<01/.02

(Snap)





















43. Celery

Air: 1.5
Other: 1.5

.13

.06

.07

.01

.06 / .92

.03 / .42

.04/.52

<01/.06

<01 / .01

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

.13

.06

.07

.01

.07 / .92

.03 / .42

.04/.52

<01/.06

<01 / .01

45. Anise

Air: .9375
Other: .9375

.10

.04

.05

.01

.05 / .69

.02 / .32

.03/.39

<01/.04

<01 / .01

46. Strawberry

Air: 2
Other: 2

.22

.10

.13

.01

.11*/ 1.62#

.05 / .74

.06/.91

.01/.10

<01/.02

181


-------




Dictarv-bascd Chronic RQs

Dose-based RQs (Acute/ Chronic)











Fruit/

Herbivores and Inscctivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadlcat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

47. Sugar Beet

Air: 1.875
Other: 1.875

.19

.09

.11

.01

.10/1.37#

.04 / .63

.05 / .77

.01/.09

<01/.02

48. Tomato

Air: 3.5
Other: 3.5

.43

.20

.24

.03

.22*/3.11#

.10*/ 1.42#

.12*/1.75#

.01/.19

<01/.04

49. Okra

Air: 1.5
Other: 1.5

.17

.08

.09

.01

.09/1.21#

.04 / .56

.05 / .68

.01/.08

<01 / .02

51. Sorghum

Air: 1.5
Other: 1.5

.14

.07

.08

.01

.07/ 1.03#

.03 / .47

.04/.58

<01/.06

<01 / .01

52. Barley, Cereal Grains,
Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

.12

.05

.07

.01

.06 / .86

.03 / .39

.03 / .48

<01/.05

<01 / .01

53. Gooseberry

Air: 16
Other: 16

1.72

.79

.97

.11

.88$/ 12.4#

.40*/5.7#

.49*/7#

.05 / .78

.01 / .17

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and
Raspberry (Black - Red)

Air: 4
Other: 4

.43

.20

.24

.03

.22*/3.11#

.10*/ 1.43#

.12*/1.75#

.01/.19

<01/.04

55. Blueberry

Air: 2.5
Other: 2.5

.33

.15

.18

.02

.17*/2.37#

.08/ 1.09#

.09/ 1.34#

.01/.15

< 01 / .03

56. Caneberries and Currant

Air: 2
Other: 2

.22

.10

.12

.01

.11*/ 1.56#

.05/.71

.06 / .88

.01/.10

<01/.02

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

.08

.04

.05

.01

.04/.61

.02 / .28

.02/.34

<01/.04

<01 / .01

58. Mint and Spearmint

Air: 1
Other: 1

.10

.04

.05

.01

.05 / .69

.02 / .32

.03/.39

<01/.04

<01 / .01

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

.15

.07

.08

.01

.08/ 1.07#

.03 / .49

.04 / .60

<01/.07

<01 / .01

61. Water Cress

Air: 2
Other: 2

.25

.11

.14

.02

.13*/ 1.78#

.06/.81

.07/1.0

.01/.11

<01/.02

182


-------


Dietary-based Chronic RQs

Dose-based RQs (Acute/ Chronic)



1 1 Fruit/

Herbivores and Inscctivorcs

Granivorcs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broadleat
Plants/
Small
Insects

Pods/
Seeds/
Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Seeds

Non-agricultural Uses

Forestry. Christmas Tree
Plantations, Pine (Seed
Orchard), and Slash Pine
(Forest)

Air: 3.2
Other: 3.2

.26

.12

.15

.02

.13*/ 1.89#

.06 / .87

.08/ 1.07#

.01/.12

< 01 / .03

Mosquito Control.

Intermittently Flooded
Areas/Water,

Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs
(without Human or Wildlife
Use), Polluted Water, and
Swamps/MarshesAV etlands/St
agnant Water

Air: .6
Other: .6

.05

.02

.03

<01

.03 / .36

.01 / .17

.01/.20

<01/.02

<01 / .01

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

.28

.13

.16

.02

.14*/ 2.0#

.06 / .92

.08/1.12#

.01/.12

< 01 / .03

Public Health and Medfly
Control. Nonagricultural
Areas (Public Health Use),
Urban Areas, and Wide
Area/General Outdoor
Treatment (Public Health
Use)

Air: .6119
Other: .1361

.06
.01

.03
.01

.04
.01

<01
<01

.03 / .45
.01 / .10

.01 / .21
<01 / .05

.02 / .25
<01/.06

<01/.03
<01/. 01

<01 / .01
<01/ <01

183


-------




Dictarv-bascd Chronic RQs

Dose-based RQs (Acute/ Chronic)











Fruit/

Herbivores and Inscctivorcs

Granivorcs



Maximum





Broadleat

Pods/







Broad leaf

Fruit/





Application





Plants/

Seeds/







Plants/

Pods/Seeds/



Scenario Group:

Rates1

Short

Tall

Small

Large

Short



Tall

Small

Large



Crop/Site

(Lbs. ai/A)

Grass

Grass

Insects

Insects

Grass



Grass

Insects

Insects

Seeds

Residential.























Household/Domestic























Dwellings Outdoor Premises,























Ornamental and/or Shade























Trees, Ornamental























Herbaceous Plants,

Other: ,253

.03

.01

.01

<01

.01 / .19



.01 / .09

.01/.10

<01/. 01

<01 / <01

Ornamental Lawns and Turf,























Ornamental Non-flowering























Plants, Ornamental Woody























Shrubs and Vines, and Urban























Areas























Rights-of-way.

Nonagricultural Rights-of-
way/Fencerows/Hedgerows
and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

.08

.03

.04

<01

.04 / .55

.02 / .25

.02/.31

<01/.03

<01 / .01

Turf. Golf Course Turf
(Bermudagrass)

Air: 1.25
Other: 1.25

.10

.05

.06

.01

.05 / .76

.02/.35

.03 / .43

<01/.05

<01 / .01

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

*	Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

#	Chronic RQ >1.0 for listed and non-listed species.

184


-------
Avian Prey

Table 40 present risk quotients for avian food items of the CRLF. Chronic dietary RQs
trigger concern levels for all but 2 use scenarios (residential yard lawn and ornamental
use and the papaya use). Acute listed and non-listed species concern levels are exceeded
by dose-based RQs in one or more food items for all use scenarios. Dietary-based acute
RQs exceed the listed species LOC in one or more food residue categories for all uses
except papaya, residential lawn and ornamental, and mosquito control uses. Eighteen use
scenarios show dietary RQs that exceed the non-listed species acute LOC.

185


-------
Table 40. Assessment of indirect effects on the terrestrial phase of the California Red-legged Frog (CRLF based on dietary- and dose-based risk
quotients (RQs) for small (20 g) birds (used as surrogate for CRLF).		





Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broad leaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Agricultural Uses

1. Alfalfa, Clover, Lespedeza,
Lupine, Trefoil, and Vetch

Air: 2
Other: 2

0.32*/6.17#

0.15*/2.83#

0.18*/3.47#

0.02/0.39

8.48$

3.89$

4.77$

0.53$

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

2.88$/55.7#

1.32$/25.5#

1.62$/31.3#

.18*/3.48#

76.6$

35.1$

43.1$

4.79$

3. Pecan and Walnut
(English/Black)

Air: 12.5
Other: 12.5

2.38$ / 46.1#

1.09$ / 21.1#

1.34$/25.9#

.15*/2.88#

63.4$

29.0$

35.6$

3.96$

4. Chestnut

Air: 5
Other: 5

.93$/ 18.1#

.43*/8.28#

.53$/ 10.2#

.06/1.13#

24.8$

11.4$

14.0$

1.55$

5. Almond

Air: 1.25
Other: 4

.24*/4.61#
.76$ / 14.7#

.11* / 2.11#
.35*/6.76#

.13* / 2.59#
.43*/8.30#

.01/.29
.05 / .92

6.34$
20.3$

2.90$
9.29$

3.56$
11.4$

.40*
1.27$

6. Date

Air: 1
Other: 2

.14*/2.62#
.27* / 5.24#

.06/ 1.20#
.12*/2.40#

.08/ 1.47#
.15*/2.95#

.01/.16
.02/.33

3.60$
7.20$

1.65$
3.30$

2.03$
4.05$

.23*
.45*

7. Filbert (Hazelnut)

Air: .625
Other: .625

.12*/2.30#

.05/ 1.06#

.07/ 1.30#

.01/.14

3.17$

1.45$

1.78$

.20*

8. Avocado

Air: 9
Other: 9

1.49$/28.9#

.68$/ 13.2#

.84$/ 16.2#

.09/ 1.80#

39.7$

18.2$

22.3$

2.48$

9. Citrus, Citrus Hybrids other
than Tangelo, Grapefruit,
Kumquat, Lemon, Lime,
Orange, Tangelo, and
Tangerines

Air: 25
Other: 25

4.76$ / 92.2#

2.18$/42.2#

2.68$/51.8#

.30*/5.76#

127$

58.1$

71.3$

7.92$

186


-------




Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

10. Amaranth - Chinese,
Broccoli (Unspecified,
Chinese, and Raab), Cabbage
(Unspecified and Chinese),
Canola\Rape, Cauliflower,
Collards, Corn Salad, Dock
(Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard
Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden
and Winter)

Air: 2.5
Other: 2.5

.48* / 9.26#

.22*/4.24#

.27*/5.21#

.03/.58

12.7$

5.83$

7.16$

.80$

11. Corn (Unspecified, Field,
Pop, and Sweet) and Millet
(Foxtail)

Air: 1.5
Other: 1.5

.40*/7.79#

.18*/3.57#

.23*/4.38#

.03 / .49

10.7$

4.91$

6.03$

.67$

12. Cotton

Air: 4
Other: 4

1.43$/27.7#

.66$ / 12.7#

.81$/ 15.6#

.09/ 1.73#

38.1$

17.5$

21.4$

2.38$

15. Apricot

Air: 10
Other: 10

2.02$/39.1#

.93$/ 17.9#

1.14$/22.0#

.13*/2.45#

53.8$

24.7$

30.3$

3.36$

16. Nectarine and Peach

Air: 9
Other: 9

1.82$/35.2#

.83$/ 16.1#

1.02$/ 19.8#

.11*/2.20#

48.4$

22.2$

27.2$

3.03$

17. Cherry

Air: 8
Other: 8

1.68$/32.5#

.77$/ 14.9#

.95$/ 18.3#

.11* / 2.03#

44.7$

20.5$

25.2$

2.80$

18. Fig

Air: 2.5
Other: 2.5

.51$/9.91#

.23*/4.54#

.29*/5.57#

.03 / .62

13.6$

6.24$

7.66$

.85$

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

.27*/5.14#
.32*/6.17#

.12*/2.35#
.15* / 2.83#

.15*/2.89#
.18*/3.47#

.02/.32
.02/.39

7.06$
8.48$

3.24$
3.89$

3.97$
4.77$

.44*
.53$

20. Guava, Mango, Plum, and
Prune

Air: .75
Other: 1.5

.16*/3.08#
.32*/6.17#

.07/1.41#
.15* / 2.83#

.09/ 1.73#
.18*/3.47#

.01/.19
.02/.39

4.24$
8.48$

1.94$
3.89$

2.39$
4.77$

.27*
.53$

21. Papaya

Air: .175
Other: .175

.04 / .72

.02/.33

.02 / .40

<01/.04

.99$

.45*

.56$

.06

187


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Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

22. Garlic and Leek

Air: 2
Other: 2

.38*/7.35#

.17*/3.37#

.21*/4.14#

.02 / .46

10.1$

4.63$

5.69$

.63$

23. Grapes

Air: 2.75
Other: 27.47

.46* / 8.82#
4.55$/88.1#

.21*/4.04#
2.09$/40.4#

.26*/4.96#
2.56$/49.5#

.03/.55
.28*/5.50#

12.1$
121$

5.56$
55.5$

6.82$
68.1$

.76$
7.57$

26. Brussel Sprouts and
Dandelion

Air: 2.5
Other: 2.5

.45*/8.65#

.20*/3.96#

.25*/4.86#

.03 / .54

11.9$

5.45$

6.69$

.74$

27. Swiss Chard, Chervil,
Endive (Escarole), Lettuce,
Head Lettuce, Leaf Lettuce
(Black Seeded Simpson,
Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley,
Roquette (Arrugula), Salsify,
and Spinach

Air: 2
Other: 2

.47*/9.12#

.22*/4.18#

.27*/5.13#

.03 / .57

12.5$

5.75$

7.05$

.78$

28. Peppermint

Air: 1
Other: 1

.18*/3.46#

.08/ 1.59#

.10*/1.95#

.01/0.22

4.76$

2.18$

2.67$

.30*

29. Eggplant

Air: 3.5
Other: 3.5

.81$/ 15.6#

.37*/7.17#

.45*/8.80#

.05 / .98

21.5$

9.85$

12.1$

1.34$

30. Pumpkin

Air: 2
Other: 2

.42*/8.14#

.19*/3.73#

.24*/4.58#

.03/.51

11.2$

5.13$

6.29$

.70$

31. Cucumber, Cucurbit
Vegetables, Melons -
Unspecified, Cantaloupe,
Honeydew, Musk, Water, and
Winter

(Casaba/Crenshaw/Honeydew
/Persian), and Squash (All Or
Unspecified)

Air: 1.875
Other: 1.875

.39*/7.63#

.18*/3.50#

.22*/4.29#

.02 / .48

10.5$

4.81$

5.90$

.66$

32. Onion (Unspecified and
Green), Radish, and Shallot

Air: 2
Other: 2

.38*/7.35#

.17*/3.37#

.21*/4.14#

.02 / .46

10.1$

4.63$

5.69$

.63$

33. Potato - White/Irish

Air: 3
Other: 3

.57$/ 11.0#

.26* / 5.06#

.32*/6.21#

.04 / .69

15.2$

6.95$

8.53$

.95$

188


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Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs



Maximum













Broadlcaf

Fruit/



Application





Broad leaf

Fruit/ Pods/





Plants/

Pods/Seeds/

Scenario Group:

Rates1

Short

Tall

Plants/Small

Seeds/Large

Short

Tall

Small

Large

Crop/Site

(Lbs. ai/A)

Grass

Grass

Insects

Insects

Grass

Grass

Insects

Insects

34. Turnip

Air: 2.5
Other: 2.5

.48*/9.19#

.22*/4.21#

.27*/5.17#

.03 / .57

12.6$

5.79$

7.11$

.79$

35. Parsnip and Rutabaga

Air: 2
Other: 2

.38*/7.35#

.17*/3.37#

.21*/4.14#

.02 / .46

10.1$

4.63$

5.69$

.63$

36. Sweet Potato

Air: 1.875
Other: 1.875

.30*/5.78#

.14*/2.65#

.17*/3.25#

.02/.36

7.95$

3.64$

4.47$

.50$

37. Bluegrass, Canarygrass,
Grass Forage/Fodder/Hay,
Pastures, Peas (Including

Air: 1.25
Other: 1.25

.37*/7.25#

.17*/3.32#

.21*/4.08#

.02 / .45

9.97$

4.57$

5.61$

.62$

Vines), Rangeland,
Sudangrass, and Timothy

















40. Beets, Cowpea/Blackeyed
Pea, and Peas (Unspecified

Air: 2.5
Other: 2.5

.48*/9.19#

.22*/4.21#

.27*/5.17#

.03 / .57

12.6$

5.79$

7.11$

.79$

and Field)

















41. Carrot (Including Tops),
Celtuce, Fennel, and Pepper

Air: 2
Other: 2

.48* / 9.22#

.22*/4.23#

.27*/5.19#

.03/.58

12.7$

5.81$

7.13$

.79$

42. Beans, Beans - Dried-



















Type, Beans - Succulent
(Lima), and Beans -

Air: 1.75
Other: 1.75

.33*/6.45#

.15*/2.96#

.19*/3.63#

.02 / .40

8.87$

4.07$

4.99$

.55$

Succulent (Snap)



















43. Celery

Air: 1.5
Other: 1.5

.24*/4.63#

.11* / 2.12#

.13*/2.60#

.01/.29

6.36$

2.92$

3.58$

.40*

44. Asparagus and Safflower
(Unspecified)

Air: 1.25
Other: 1.25

.24*/4.65#

.11* / 2.13#

.14*/2.62#

.02 / .29

6.40$

2.93$

3.60$

.40*

45. Anise

Air: .9375
Other: .9375

.18*/3.48#

.08/ 1.60#

.10*/1.96#

.01/.22

4.79$

2.19$

2.69$

.30*

46. Strawberry

Air: 2
Other: 2

.42*/8.14#

.19*/3.73#

.24*/4.58#

.03/.51

11.2$

5.13$

6.29$

.70$

47. Sugar Beet

Air: 1.875
Other: 1.875

.36*/6.89#

.16*/3.16#

.20*/3.88#

.02 / .43

9.48$

4.34$

5.33$

.59$

189


-------


Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

48. Tomato

Air: 3.5
Other: 3.5

.81$/ 15.6#

.37*/7.17#

.45*/8.80#

.05 / .98

21.5$

9.85$

12.1$

1.34$

49. Okra

Air: 1.5
Other: 1.5

.32*/6.10#

.14*/2.80#

.18*/3.43#

.02/.38

8.39$

3.85$

4.72$

.52$

51. Sorghum

Air: 1.5
Other: 1.5

.27*/5.19#

.12*/2.38#

.15*/2.92#

.02/.32

7.13$

3.27$

4.01$

.45*

52. Barley, Cereal Grains,
Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

.22*/4.32#

.10*/1.98#

.13*/2.43#

.01/.27

5.94$

2.72$

3.34$

.37*

53. Gooseberry

Air: 16
Other: 16

3.24$/62.6#

1.48$/28.7#

1.82$/35.2#

.20*/3.91#

86.1$

39.4$

48.4$

5.38$

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and
Raspberry (Black - Red)

Air: 4
Other: 4

.81$/ 15.7#

.37*/7.17#

.46* / 8.80#

.05 / .98

21.5$

9.86$

12.1$

1.34$

55. Blueberry

Air: 2.5
Other: 2.5

.62$/ 11.9#

.28* / 5.47#

.35*/6.72#

.04 / .75

16.4$

7.52$

9.24$

1.03$

56. Caneberries and Currant

Air: 2
Other: 2

.40*/7.83#

.19*/3.59#

.23*/4.40#

.03 / .49

10.8$

4.93$

6.05$

.67$

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

.16*/3.08#

.07/1.41#

.09/ 1.73#

.01/.19

4.23$

1.94$

2.38$

.26*

58. Mint and Spearmint

Air: 1
Other: 1

.18*/3.46#

.08/ 1.59#

.10*/1.95#

.01/0.22

4.76$

2.18$

2.67$

.30*

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

.28*/5.40#

.13*/2.48#

.16*/3.04#

.02/.34

7.43$

3.41$

4.18$

.46*

61. Water Cress

Air: 2
Other: 2

.46*/8.93#

.21*/4.10#

.26*/5.03#

.03 / .56

12.3$

5.63$

6.91$

.77$

Non-agricultural Uses

Forestry. Christmas Tree
Plantations, Pine (Seed
Orchard), and Slash Pine
(Forest)

Air: 3.2
Other: 3.2

.49*/9.52#

.23*/4.36#

.28*/5.36#

.03 / .60

13.1$

6.00$

7.36$

.82$

190


-------


Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Short

Grass

Tall

Grass

Broad leaf
Plants/Small
Insects

Fruit/ Pods/
Seeds/Large
Insects

Short

Grass

Tall

Grass

Broadlcaf
Plants/
Small
Insects

Fruit/
Pods/Seeds/
Large
Insects

Mosquito Control.

Intermittently Flooded
Areas/Water,

Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs
(without Human or Wildlife
Use), Polluted Water, and
Swamps/MarshesAV etlands/S
tagnant Water

Air: .6
Other: .6

.09/ 1.82#

.04 / .84

.05/ 1.03#

.01/.11

2.51$

1.15$

1.41$

.16*

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

.52$/ 10.1#

.24*/4.61#

.29* / 5.66#

.03 / .63

13.8$

6.34$

7.78$

.86$

Public Health and Medfly
Control. Nonagricultural
Areas (Public Health Use),
Urban Areas, and Wide
Area/General Outdoor
Treatment (Public Health
Use)

Air: .6119
Other: .1361

.12*/2.28#
.03 / .51

.05/ 1.04#
.01/.23

.07/ 1.28#
.01/.28

.01/.14
<01/.03

3.13$
.70$

1.44$
.32*

1.76$
.39*

.20*
.04

Residential.

Household/Domestic
Dwellings Outdoor Premises,
Ornamental and/or Shade
Trees, Ornamental
Herbaceous Plants,
Ornamental Lawns and Turf,
Ornamental Non-flowering
Plants, Ornamental Woody
Shrubs and Vines, and Urban
Areas

Other: ,253

.05 / .94

.02 / .43

.03/.53

<01/.06

1.29$

.59$

.73$

.08

191


-------




Dictarv-bascd Acute RQs (Acute/ Chronic)

Dose-based Acute RQs



Maximum













Broadlcaf

Fruit/



Application





Broad leaf

Fruit/ Pods/





Plants/

Pods/Seeds/

Scenario Group:

Rates1

Short

Tall

Plants/Small

Seeds/Large

Short

Tall

Small

Large

Crop/Site

(Lbs. ai/A)

Grass

Grass

Insects

Insects

Grass

Grass

Insects

Insects

Rights-of-way.

Nonagricultural Rights-of-
way/Fencerows/Hedgerows
and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

.14*/2.76#

.07/ 1.27#

.08/ 1.55#

.01/.17

3.80$

1.74$

2.14$

.24*

Turf. Golf Course Turf
(Bermudagrass)

Air: 1.25
Other: 1.25

.20*/3.80#

.09/ 1.74#

.11* / 2.14#

.01/.24

5.23$

2.40$

2.94$

.33*

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

*	Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

#	Chronic RQ >1.0 for listed and non-listed species.

192


-------
Terrestrial Invertebrate Prey

Commonly, terrestrial insect prey base risk assessments involve an assessment of on and
off-field risk calculations. Like other insecticide uses, there are a variety of agricultural
scenarios of malathion use that involve direct application to agriculture. However, there
are also labeled uses that are much more varied in potential use site geography and
include rights of way, public health programs, medfly control, forestry, and mosquito
control. Therefore it was assumed that drift assessment off site, while suitable for
evaluating a single use site of a pesticide, in this case, were probably of limited utility
because direct application to these areas was also possible, and would tend to dominate
the risk conclusions.

Consequently RQ calculations were conducted to evaluate effects on terrestrial
invertebrates. The risk discussion section of this document will rely on other lines of
evidence.

5.1.4.2 Terrestrial Phase Indirect Effects via Reduction in Terrestrial Plant
Community (Riparian Habitat)

The risk assessment process relies predominantly on effects endpoints associated with
seedling emergence, growth, and plant viability. There are no submitted registrant data
for malathion and terrestrial plants. A review of the available ECOTOX data, meeting
OPP data quality criteria, did not show any effects on emergence, growth, and plant
viability for any dicot plants species under any application conditions. Therefore, EFED
concludes malathion applications consistent with the current label are likely to have no
indirect effect on the CRLF via Reduction in Terrestrial Plant Community (Riparian
Habitat) (Table 1).

5.2 Risk Description

The risk description synthesizes an overall conclusion regarding the likelihood of adverse
impacts leading to an effects determination (i.e., "no effect," "may affect, but not likely
to adversely affect," or "likely to adversely affect") for the CRLF.

If the RQs presented in the Risk Estimation (Section 5.1) show no indirect effects and
LOCs for the CRLF are not exceeded for direct effects, a "no effect" determination is
made, based on use of malathion within the action area. If, however, indirect effects are
anticipated and/or exposure exceeds the LOCs for direct effects, the Agency concludes a
preliminary "may affect" determination for the CRLF. Following a "may affect"
determination, additional information is considered to refine the potential for exposure at
the predicted levels based on the life history characteristics (i.e., habitat range, feeding
preferences, etc.) of the CRLF and potential community-level effects to aquatic plants.
Based on the best available information, the Agency uses the refined evaluation to
distinguish those actions that "may affect, but are not likely to adversely affect" from
those actions that are "likely to adversely affect" the CRLF.

193


-------
The criteria used to make determinations that the effects of an action are "not likely to
adversely affect" the CRLF include the following:

•	Significance of Effect. Insignificant effects are those that cannot be meaningfully
measured, detected, or evaluated in the context of a level of effect where "take"
occurs for even a single individual. "Take" in this context means to harass or
harm, defined as the following:

•	Harm includes significant habitat modification or degradation that results in
death or injury to listed species by significantly impairing behavioral patterns
such as breeding, feeding, or sheltering.

•	Harass is defined as actions that create the likelihood of injury to listed
species to such an extent as to significantly disrupt normal behavior patterns
which include, but are not limited to, breeding, feeding, or sheltering.

•	Likelihood of the Effect Occurring: Discountable effects are those that are
extremely unlikely to occur. For example, use of dose-response information to
estimate the likelihood of effects can inform the evaluation of some discountable
effects.

•	Adverse Nature of Effect. Effects that are wholly beneficial without any adverse
effects are not considered adverse.

Table 41 presents the conclusions of effects determinations for aquatic and terrestrial
phase amphibians from either direct or indirect effects.

Table 41. Malathion Effects Determination Summary for the CRLF.

Assessment
Endpoint

Exposure
(Duration,
Habitat)

Effects
Determination1

Basis for Determination

Direct effects to
CRLF

Acute,
aquatic

LAA

-	Acute LOC2 is exceeded for most uses based
on estimated concentrations of malathion in
water and on the most sensitive surrogate
vertebrate data.

-	At the highest estimated concentration of
malathion in water, the likelihood of individual
mortality is well in excess of 1 in 2.

-	Maximum observed concentrations of
malathion in surface waters are sufficient to
exceed the LOC.



Chronic,
aquatic

LAA

- Chronic LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and on the most sensitive surrogate vertebrate
data extrapolated to a chronic endpoint through
the application of an ACR.

194


-------
Assessment
I'lmlpoini

l'l\|)OMIIV

(l)iii'iilion.
Iliihiliil)

i.nvcis
Dcloi'iniiiiilioii1

liiisis Idi- Doloi'iniiiiilioii



Acute,
terrestrial

LAA

-	Using the avian surrogate approach the acute
listed species LOC is exceeded for 53 of 68 use
scenarios.

-	Refined estimates of exposure based on CRLF-
specific diet considerations result in listed
species LOC exceedances for dose-based or
dietary-based exposures for 53 uses and reduces
uses exceeding the non-listed LOC to 8.



Chronic,
terrestrial

LAA

-	Chronic LOC is exceeded for all uses, except
the papaya and residential ornamental and lawn
uses, based on the most sensitive surrogate bird
data.

-	Refined estimates of exposure based on CRLF-
specific diet considerations result in LOC
exceedances for dietary-based exposures except
for papaya and residential ornamental and lawns.

Indirect effects to
tadpole CRLF via
reduction of
primary
production based
food
(i.e., algae)

Aquatic

NLAA

-	Only the listed species LOC is exceeded for
some uses of malathion.

-	However, the listed species LOC is only
applicable for indirect effects to listed species
with an obligate relationship to a specific plant,
which is not applicable to the CRLF which is a
generalist herbivore.

Indirect effects to
juvenile and adult

CRLF via
reduction of prey
(i.e.,
invertebrates)

Acute,
aquatic

LAA

-	Acute LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and on the most sensitive surrogate invertebrate
data.

-	Estimated concentrations of malathion in water
resulting from all uses result in a likelihood of
individual mortality of 50% to 100% for the
most sensitive species tested.

-	Considering species sensitivity distributions for
aquatic vertebrates and estimated exposure
concentrations for malathion, all uses may affect
substantial numbers of invertebrate species at
50% or greater mortality.



Chronic,
aquatic

LAA

- Chronic LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and the most sensitive surrogate invertebrate
data.



Acute,
terrestrial

LAA

Malathion is an insecticide with a highly varied
suite of agricultural and non-agricultural uses.
Field effects data show that label relevant
application rates can reduce invertebrate
populations at sites of treatment.

195


-------
Assessment
I'lmlpoini

l'l\|)OMIIV

(l)iii'iilion.
Iliihiliil)

i.nvcis
Dcloi'iniiiiilioii1

liiisis for Doloi'iniiiiilioii

Indirect effects to
adult CRLF via
reduction of prey
(i.e., fish, frogs,
and mice)

Acute,
aquatic

LAA

-	Acute LOC is exceeded for several uses based
on estimated concentrations of malathion in
water and the most sensitive surrogate vertebrate
data.

-	At the highest estimated concentration of
malathion in water (resulting from use on
lettuce), the level of effects on exposed
populations exceeds 50%.

-	Maximum observed concentrations of
malathion in surface waters are sufficient to
exceed the LOC.

-	Considering species sensitivity distributions for
aquatic vertebrates and estimated exposure
concentrations for malathion several uses
(gooseberry, rice/wild rice, watercress, forestry,
and mosquito control) may affect substantial
numbers of fish species at 50% or greater
mortality.



Chronic,
aquatic

LAA

- Chronic LOC is exceeded for all uses based on
estimated concentrations of malathion in water
and on the most sensitive surrogate vertebrate
data.



Acute,
terrestrial

LAA

-	Acute LOC is exceeded for all uses based on
the most sensitive surrogate amphibian data.

-	Refined estimates of exposure based on
amphibian-specific diet considerations result in
LOC exceedances for dietary-based and dose-
based exposures.

-	For foliar uses, effects determination based on
acute effects to mice is NLAA.



Chronic,
terrestrial

LAA

-	Chronic LOC is exceeded for all foliar uses
based on the most sensitive surrogate
mammalian and amphibian data.

-	Refined estimates of exposure based on
amphibian-specific diet considerations result in
LOC exceedances for dietary-based exposures.

Indirect effects to
CRLF via
reduction of
habitat and/or
primary
productivity (i.e.,
plants)

Aquatic

NE

-	Only the listed species LOC is exceeded for
some uses of malathion.

-	However, the listed species LOC is only
applicable for indirect effects to listed species
with an obligate relationship to a specific plant,
which is not applicable to the CRLF (a generalist
herbivore).



Terrestrial

NE

-There are no data to support any finding that
field relevant effects on terrestrial plants occur
with any field relevant application of malathion.

1LAA = likely to adversely affect; NLAA = not likely to adversely affect; NE = no effect

196


-------
2Although a number of uses exceed the acute risk LOC for listed species, it is possible that for at least some
of these uses, the likelihood of individual mortality may be sufficiently low to arrive at a NLAA
determination.

5.2.1 Direct Effects to the California Red Legged Frog

5.2.1.1 Aquatic Phase Direct Effects

Of the 68 use scenarios modeled for this assessment, all but two yielded acute water
concentration estimates in excess of the non-listed species effects benchmark equivalent
to one-half of the lowest median lethal concentration for larval stage amphibians. In fact
the RQ values for these 66 uses exceed the larval frog medial lethal concentration,
suggesting that the chance of mortality for frogs exposed to concentrations equivalent to
those modeled is greater than 1 in 2. Because exposures are several times to hundreds of
times greater than the acute endpoints, regardless of the slope of the dose response curve
for larval frog toxicity, the probability for individual mortality may be more than 99%.

Section 3.1.2 presents a figure on the use of malathion over the course of several years.
The pattern suggests that usage increases in the spring to peak in summer and rapid taper
off in the fall. Superimposing this pattern on critical stages in the frog life history (Figure
2) suggests that the development cascade from egg to tadpole to young juveniles occurs
during the March though August period of the year. Highest malathion usage appears to
be restricted to periods when young juveniles are most likely present in aquatic systems.
The overlap of life stage data with usage data suggests that it is feasible that reproduction
effects, as manifested in the survival growth and development from egg though larval
stages, are a concern. However, at the height of malathion season, young juveniles, and
the potential for acute lethal effects on this life state, may be of the highest concern. As a
consequence, use of the available larval effects data for malathion for acute effects
introduces considerable uncertainty in the extrapolation of such effects to juvenile frogs.
This uncertainty may lead to either over or underestimation of effects at this juvenile life
stage. However, given the very high magnitudes of effects encountered for many of the
risk estimations of labeled uses, it is unlikely that higher resolution information on young
juvenile frog sensitivity to malathion would result in radical alterations of the risk
assessment conclusions.

As can be seen in Figure 14 potential use sites which span a variety agricultural crops
(NOTE Review panel) including orchards and vineyards is extensive in California
suggesting that there is a reasonable opportunity for malathion use in any given
agricultural area and these areas do coincide with the frog.

197


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Agricultural Land and
California Red-legged Frog Range

J J

c-A,

Legend



i

i

Agricultural Land Use

C riiic.31 Hahital	„	\

CNDDB Occurrence Sections

U Currently Occupied Care Areas
CDunty Boundary

ti

V



>

T—r-

t / jI

/

<

3D 10D

300
Hi Mi lyy

Compiled from Calrfornia County boundaries (ESRI.2C02).
U SO A N alio nal Agriculture Statistical Eten/ice (TMASS,20D2)
Gap Analysis Program Orchard/Vine'/ad Landcover (GAP)
National Land Cover Dal abase (NLCD) (MRLC.2Q01)

Map created by U.S. Environmental Protection Agency,
Office of Pesticides Programs, Environmental Fate and
EllHUtb Divi'siun May 4, 2DD7 (PDB)

Pr cje d 'on; Alb er? Equ a! Are a C on< c U S£ S,

North American Datum of 1933 (NAD 1933)

Figure 14. Comparison of the range of the California Red-legged Frog (CRLF) location of
agricultural lands in California.

Because malathion is also used as a mosquito control agent it is expected that its use will
be closely associated with surface waters and such uses can occur anywhere across the
state. Additional uses such as medfly control suggest there is opportunity for the pesticide
to be used in areas where this pest may be detected and those areas may involve places
outside of agricultural use, save possibly desert regions which are outside the known
range of the CRLF.

There are adequate lines of evidence to conclude that labeled malathion use can produce
water exposure levels with high probability to be lethal to individual larval frogs and that

198


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the use sites associated with malathion coincide spatially with areas potentially inhabited
by aquatic phase frogs. While malathion peak usage in California does not fully coincide
with the larval life stage of the frog, there is still temporal overlap of the larval stages
with periods of malathion use and one cannot preclude the reasonable possibility of
exposures of larval frogs to lethal malathion concentrations. Moreover, juvenile and adult
frogs may also be present in water, and information on the life cycle suggests that these
stages may be present in water at time periods of peak malathion use in California.

Insofar as the available acute toxicity data for larval frogs is used to characterize toxic
risks to all aquatic phases, there is evidence to suggest that individual adult and juvenile
frogs are at lethal risk from malathion use.

All uses of malathion assessed in this document triggered concerns for reproduction
(chronic) effects in aquatic phase frogs. As stated earlier, patterns of malathion use
suggest that the periods of greatest application of the pesticide do not coincide with egg
and larval stages. Nevertheless, patterns of malathion use in California still suggests that
uses overlap temporally to some extent with egg and larval stages in the reproduction
cycle. The available chronic toxicity data available for fish, the data used for
extrapolation of frog reproduction effects, suggests that the differences between the
NOAEC and LOAEC values (no effect and frank effects for reproduction) is less than a
factor of two. The significance of this difference is that any use sites with a chronic
aquatic phase frog RQ greater than 2 falls within an area of potentially high confidence
for producing adverse effects with respect to individual production of viable offspring. In
every use scenario modeled, the chronic malathion RQ was several to hundreds of times
greater than the extrapolated NOAEC, which is highly suggestive of a potential to
produce adverse effects on the ability of exposed frogs to reproduce.

Again there are adequate lines of evidence to conclude that labeled malathion use can
produce water exposures at levels likely to impair the reproductive capacity of individual
larval frogs, and the use sites associated with malathion coincide spatially with areas
inhabited by aquatic phase frogs. While California usage data does not suggest that peak
malathion usage occurs during egg and larval life cycle stages, there is still sufficient
temporal overlap to suggest that exposures to reproductively significant levels of
malathion is reasonably possible. Therefore the effects finding for direct acute effects
to the CRLF is that malathion labeled use is likely to adversely affect individuals of
the species (LAA).

One area of uncertainty with respect to the assessment of aquatic phase frogs is the
selection of the acute endpoint. This endpoint (LD50 0.59 |ig/L) is derived from the most
sensitive larval frog tested and the potential for it to be an outlier is suggested when
compared to the range of similar endpoints for other tested larval frogs (200 to 9810
|ig/L), Careful review of the testing protocol showed no significant problems with
toxicity methods except for the use of wild caught organisms. To determine if this species
was unusually sensitive or that wild caught individuals were somehow highly stressed or
susceptible to pesticide intoxication, a comparison of other pesticide endpoints was made
with available ranges for other tested amphibians with those chemicals. This comparison
indicated that acute effect endpoints for this test species with other pesticides fell within

199


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the range of toxicities for other tested amphibians with those chemicals. It was concluded
that there was insufficient evidence to declare the existing malathion larval frog acute
toxicity endpoint an outlier. It should be noted that, even if this endpoint was not selected
for use, a default to the most sensitive fish endpoint (policy in the absence of amphibian
data) would not alter the risk conclusions for aquatic phase amphibians.

Another area of uncertainty with the assessment of direct effects to the aquatic phase of
the frog is the extrapolation of available fish chronic data to aquatic phase amphibians.
While amphibian eggs and larvae are in direct contact with the water for extended
periods, adult frogs may or may not be. However, the majority of available fish chronic
effects data are from early life stage tests, which involve direct exposure of eggs and
developing fry of fish to the toxicant and not adult stage breeding organisms. Given the
nature of the testing methods and the large RQ values for chronic effects to frogs in
this assessment there is insufficient evidence to dismiss chronic effects concerns for
aquatic phase frogs (LAA CRLF)

Additional consideration of maloxon impacts suggests that the conclusions reached for
malathion alone are adequate to cover the potential effects associated with maloxon.

5.2.1.2 Terrestrial Phase Direct Effects

The initial screening level risk assessment methods using avian effects data and an avian
exposure model as surrogates suggests concern for direct acute and chronic toxic risks to
frogs. In such situations where conservative screening level methods trigger concerns,
additional evaluation of potential direct effects on terrestrial phase frogs is accomplished
through the application of an exposure model modified to be more reflective of the food
requirements of amphibians (T-Herps). This involves adjusting daily food intake with an
allometric model that accounts for the lower food intake of poikilothermic reptiles and
amphibians. The net effect of this approach is a reduction in pesticide exposure due to
reduced food consumption. Tables 42 and 43 present the results of this T-Herps model
and the attendant RQ calculations for acute and chronic effects. Even under this more
species specific risk model, consumption of small insects or small mammals represent an
acute and chronic risk at levels exceeding the non-listed species LOC for most uses
except papaya and residential ornamental and lawn use. The available lines of evidence
suggest that labeled malathion uses are likely to adversely affect terrestrial phase
CRLF through direct toxic effects (LAA).

200


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Table 42. Assessment of direct effects on terrestrial phase California Red-legged Frog (CRLF) using dietary-based acute and chronic risk quotients
(RQs) based on the T-Herps model estimated environmental concentrations (EECs) for malathion.	





Dictarv-bascd RQs (Acute / Chronic) for Terrestrial Phase CRLF Direct Effects

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Small Insect
Prcv

Large Insect
Prey

Small Herbivore
Mammal
Prcv

Small Inscctivorc
Mammal
Prcv

Small Terrestrial
Phase
Amphibian
Prcv

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine, Trefoil, and
Vetch

Air: 2
Other: 2

0.18*/ 3.47#

0.02/0.39

0.21*/4.07#

0.01/0.25

0.01/0.12

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

1.62$/31.3#

.18*/3.48#

1.90$/36.7#

.12*/2.29#

.06/ 1.09#

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

1.34$/25.9#

.15*/2.88#

1.57$/30.4#

.10*/1.9#

.05 / .90

4. Chestnut

Air: 5
Other: 5

.53$/ 10.2#

.06/1.13#

.62$/ 11.9#

.04 / .74

.02/.35

5. Almond

Air: 1.25
Other: 4

.13* / 2.59#
.43*/8.30#

.01 / .29
.05 / .92

.16*/3.04#
.50$ / 9.72#

.01 / .19

.03 / .61

<01 / .09
.01 / .29

6. Date

Air: 1
Other: 2

.08/ 1.47#
.15*/2.95#

.01 / .16
.02/.33

.09/ 1.73#
.18*/3.45#

.01 /.ll
.01 / .22

<01 / .05
.01 / .10

7. Filbert (Hazelnut)

Air: .625
Other: .625

.07/ 1.30#

.01 / .14

.08/ 1.52#

<01 / .09

<01 / .04

8. Avocado

Air: 9
Other: 9

.84$/ 16.2#

.09/ 1.80#

.98$/ 19.0#

.06/1.19#

.03 / .56

9. Citrus, Citrus Hybrids other than Tangelo,
Grapefruit, Kumquat, Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

2.68$/51.8#

.30*/5.76#

3.14$/60.7#

.20*/3.80#

.09/ 1.80#

10. Amaranth - Chinese, Broccoli (Unspecified,
Chinese, and Raab), Cabbage (Unspecified and
Chinese), Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard Cabbage (Gai
Choy/Pak-Choi), and Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

.27*/5.21#

.03 / .58

.32*/6.10#

.02/.38

.01/.18

11. Corn (Unspecified, Field, Pop, and Sweet) and
Millet (Foxtail)

Air: 1.5
Other: 1.5

.23*/4.38#

.03 / .49

.27*/5.14#

.02/.32

.01/.15

201


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Dictarv-bascd RQs (Acute / Chronic) for Terrestrial Phase CRLF Direct Effects

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Small Insect
Prcv

Large Insect
Prcv

Small Herbivore
Mammal
Prcv

Small Inscctivorc
Mammal
Prcv

Small Terrestrial
Phase
Amphibian
Prcv

12. Cotton

Air: 4
Other: 4

.81$/ 15.6#

.09/ 1.73#

.94$/ 18.3#

.06/1.14#

.03 / .54

15. Apricot

Air: 10
Other: 10

1.14$/22.0#

.13*/2.45#

1.33$ / 25.8#

.08/1.61#

.04 / .76

16. Nectarine and Peach

Air: 9
Other: 9

1.02$/19.8#

.11* / 2.20#

1.20$/23.2#

.07/ 1.45#

.04 / .69

17. Cherry

Air: 8
Other: 8

.95$/ 18.3#

.11* / 2.03#

1.11$ / 21.4#

.07/ 1.34#

.03 / .64

18. Fig

Air: 2.5
Other: 2.5

.29*/5.57#

.03 / .62

.34*/6.53#

.02/.41

.01/.19

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

.15*/2.89#
.18*/3.47#

.02 / .32
.02/.39

.18*/3.39#
.21*/4.06#

.01 / .21
.01 / .25

.01/.1
.01 / .12

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

.09/ 1.73#
.18*/3.47#

.01 / .19
.02/.39

.11* / 2.03#
.21*/4.06#

.01 / .13
.01 / .25

<.01 / .06
.01 / .12

21. Papaya

Air: .175
Other: .175

.02 / .40

<01 / .04

.02 / .47

< 01 / .03

<01 / .01

22. Garlic and Leek

Air: 2
Other: 2

.21* / 4.14#

.02 / .46

.25*/4.85#

.02/.30

.01/.14

23. Grapes

Air: 2.75
Other: 27.47

.26*/4.96#
2.56$/49.5#

.03 / .55
.28*/5.50#

.30*/5.81#
3.00$/58.0#

.02 / .36
.19*/3.63#

.01 / .17
.09/ 1.72#

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

.25*/4.86#

.03 / .54

.29*/5.70#

.02/.36

.01/.17

27. Swiss Chard, Chervil, Endive (Escarole),
Lettuce, Head Lettuce, Leaf Lettuce (Black
Seeded Simpson, Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley, Roquette (Arrugula),
Salsify, and Spinach

Air: 2
Other: 2

.27*/5.13#

.03 / .57

.31* / 6.01#

.02/.38

.01/.18

28. Peppermint

Air: 1
Other: 1

.10*/ 1.95#

.01 / .22

.12*/2.28#

.01 / .14

<01 / .07

29. Eggplant

Air: 3.5
Other: 3.5

.45*/8.80#

.05 / .98

.53$/ 10.3#

.03 / .64

.02/.31

202


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Dictarv-bascd RQs (Acute / Chronic) for Terrestrial Phase CRLF Direct Effects

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Small Insect
Prcv

Large Insect
Prcv

Small Herbivore
Mammal
Prcv

Small Inscctivorc
Mammal
Prcv

Small Terrestrial
Phase
Amphibian
Prcv

30. Pumpkin

Air: 2
Other: 2

.24*/4.58#

.03 / .51

.28*/5.36#

.02/.34

.01/.16

31. Cucumber, Cucurbit Vegetables, Melons -
Unspecified, Cantaloupe, Honeydew, Musk,
Water, and Winter

(Casaba/Crenshaw/Honeydew/Persian), and
Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

.22*/4.29#

.02 / .48

.26*/5.03#

.02/.31

.01 / .15

32. Onion (Unspecified and Green), Radish, and
Shallot

Air: 2
Other: 2

.21* / 4.14#

.02 / .46

.25*/4.85#

.02/.30

.01/.14

33. Potato - White/Irish

Air: 3
Other: 3

.32*/6.21#

.04 / .69

.38*/7.27#

.02 / .45

.01/.22

34. Turnip

Air: 2.5
Other: 2.5

.27*/5.17#

.03 / .57

.31*/6.06#

.02/.38

.01/.18

35. Parsnip and Rutabaga

Air: 2
Other: 2

.21* / 4.14#

.02 / .46

.25*/4.85#

.02/.30

.01/.14

36. Sweet Potato

Air: 1.875
Other: 1.875

.17*/3.25#

.02 / .36

.20*/3.81#

.01 / .24

.01 /.ll

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas (Including
Vines), Rangeland, Sudangrass, and Timothy

Air: 1.25
Other: 1.25

.21*/4.08#

.02 / .45

.25*/4.78#

.02 / .30

.01 / .14

40. Beets, Cowpea/Blackeyed Pea, and Peas
(Unspecified and Field)

Air: 2.5
Other: 2.5

.27*/5.17#

.03 / .57

.31*/6.06#

.02/.38

.01/.18

41. Carrot (Including Tops), Celtuce, Fennel, and
Pepper

Air: 2
Other: 2

.27*/5.19#

.03 / .58

.31*/6.08#

.02/.38

.01/.18

42. Beans, Beans - Dried-Type, Beans - Succulent
(Lima), and Beans - Succulent (Snap)

Air: 1.75
Other: 1.75

.19*/3.63#

.02 / .40

.22*/4.25#

.01 / .27

.01 / .13

43. Celery

Air: 1.5
Other: 1.5

.13*/2.60#

.01 / .29

.16*/3.05#

.01 / .19

<01 / .09

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

.14*/2.62#

.02 / .29

.16*/3.07#

.01 / .19

<01 / .09

203


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Dictarv-bascd RQs (Acute / Chronic) for Terrestrial Phase CRLF Direct Effects

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Small Insect
Prcv

Large Insect
Prcv

Small Herbivore
Mammal
Prcv

Small Inscctivorc
Mammal
Prcv

Small Terrestrial
Phase
Amphibian
Prcv

45. Anise

Air: .9375
Other: .9375

.10*/ 1.96#

.01 / .22

.12*/2.29#

.01 / .14

<01 / .07

46. Strawberry

Air: 2
Other: 2

.24*/4.58#

.03 / .51

.28*/5.36#

.02/.34

.01/.16

47. Sugar Beet

Air: 1.875
Other: 1.875

.20*/3.88#

.02 / .43

.23*/4.54#

.01 / .28

.01 / .13

48. Tomato

Air: 3.5
Other: 3.5

.45*/8.80#

.05 / .98

.53$/ 10.3#

.03 / .64

.02/.31

49. Okra

Air: 1.5
Other: 1.5

.18*/3.43#

.02/.38

.21*/4.02#

.01/.25

.01/.12

51. Sorghum

Air: 1.5
Other: 1.5

.15*/2.92#

.02 / .32

.18*/3.42#

.01/.21

.01/.10

52. Barley, Cereal Grains, Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

.13* / 2.43#

.01 / .27

.15*/2.85#

.01 / .18

<01 / .08

53. Gooseberry

Air: 16
Other: 16

1.82$/35.2#

.20*/3.91#

2.13$ / 41.3#

.13* / 2.58#

.06/ 1.22#

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

.46* / 8.80#

.05 / .98

.53$/ 10.3#

.03 / .64

.02/.31

55. Blueberry

Air: 2.5
Other: 2.5

.35*/6.72#

.04 / .75

.41*/7.87#

.03 / .49

.01/.23

56. Caneberries and Currant

Air: 2
Other: 2

.23*/4.40#

.03 / .49

.27*/5.16#

.02/.32

.01/.15

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

.09/ 1.73#

.01 / .19

.10*/2.03#

.01 / .13

<01 / .06

58. Mint and Spearmint

Air: 1
Other: 1

.10*/ 1.95#

.01 / .22

.12*/2.28#

.01 / .14

<01 / .07

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

.16*/3.04#

.02 / .34

.18*/3.56#

.01 / .22

.01 /.ll

61. Water Cress

Air: 2
Other: 2

.26*/5.03#

.03 / .56

.30*/5.89#

.02/.37

.01/.17

204


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Dictarv-bascd RQs (Acute / Chronic) for Terrestrial Phase CRLF Direct Effects

Scenario Group:
Crop/Site

Maximum
Application

Rates1
(Lbs. ai/A)

Small Insect
Prcv

Large Insect
Prcv

Small Herbivore
Mammal
Prcv

Small Inscctivorc
Mammal
Prcv

Small Terrestrial
Phase
Amphibian
Prcv

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine (Seed
Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

.28*/5.36#

.03 / .60

.32*/6.28#

.02/.39

.01/.19

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs (with
Human or Wildlife Use), Lakes/Ponds/Reservoirs
(without Human or Wildlife Use), Polluted Water,
and Swamps/Marshes/Wetlands/Stagnant Water

Air: .6
Other: .6

.05*/ 1.03#

.01 /.ll

.06*/ 1.20#

<01/.08

<.01 / .04

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

.29*/5.66#

.03 / .63

.34*/6.63#

.02/.41

.01 / .20

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use), Urban
Areas, and Wide Area/General Outdoor Treatment
(Public Health Use)

Air: .6119
Other: .1361

.07/ 1.28#
.01 / .28

.01 / .14

<01 / .03

.08/1.5#
.02/.33

<01 / .09
<.01 / .02

<.01 / .04
<01 / .01

Residential. Household/Domestic Dwellings
Outdoor Premises, Ornamental and/or Shade
Trees, Ornamental Herbaceous Plants, Ornamental
Lawns and Turf, Ornamental Non-flowering
Plants, Ornamental Woody Shrubs and Vines, and
Urban Areas

Other: ,253

.03 / .53

<01 / .06

.03 / .62

<01 / .04

<01 / .02

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

.08/ 1.55#

.01 / .17

.09/ 1.82#

.01 /.ll

< 01 / .05

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

.11* / 2.14#

.01 / .24

.13* / 2.51#

.01 / .16

<01 / .07

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

* Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

205


-------
# Chronic RQ >1.0 for listed and non-listed species.

206


-------
Table 43. Assessment of direct effects on terrestrial phase California Red-legged Frog (CRLF) using dose-based acute risk quotients (RQs) based on the
T-Herps model estimated environmental concentrations (EECs) of malathion.	

Maximum

Dose-based Acute RQs for 3 Sizes (Small / Medium / Large) of Terrestrial Phase CRLF

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Small Insects

Large Insects

Small Herbivore
Mammals

Small Inscctivorc
Mammals

Small Terrestrial
Phase
Amphibian

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine, Trefoil, and
Vetch

Air: 2
Other: 2

0.09 / .09 / .06

0.01/.01/.01

N.A. / 2.5$ / .39*

N.A./. 16*/.02

N.A. /<01/<01

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

.8$/.79$/.52$

.09 / .09 / .06

N.A. / 23$ / 3.6$

N.A. / 1.4$/.22*

N.A. / .03 / .02

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

.66$/.65$/.43*

.07 / .07 / .05

N.A. / 19$/2.9$

N.A. / 1.2$/. 18*

N.A./.02/.01

4. Chestnut

Air: 5
Other: 5

.26*/.26*/. 17*

.03 / .03 / .02

N.A. / 7.4$/1.2$

N.A. / .46* / .07

N.A./.01/.01

5. Almond

Air: 1.25
Other: 4

.07 / .07 / .04
.21* / .21* / .14*

.01 / .01 / <01
.02 / .02 / .02

N.A. / 1.9$/.29*
N.A. / 6.1$/.94$

N.A./.12*/.02
N.A./.38*/.06

N.A. / <01/<01
N.A. / .01 / < 01

6. Date

Air: 1
Other: 2

.04 / .04 / .02
.08 / .07 / .05

<01/<01/<01
.01/.01/.01

N.A. / 1.1$/.17*
N.A. / 2.2$/.33*

N.A./.07/.01
N.A./.13*/.02

N.A. / <01/<01
N.A. / <01/<01

7. Filbert (Hazelnut)

Air: .625
Other: .625

.03 / .03 / .02

<01/ <01/ <01

N.A./.95$/.15*

N.A./.06/.01

N.A. /<01/<01

8. Avocado

Air: 9
Other: 9

.42*/.41*/.27*

.05 / .05 / .03

N.A. / 12$/ 1.8$

N.A./.74$/. 12*

N.A./.01/.01

9. Citrus, Citrus Hybrids other than Tangelo,
Grapefruit, Kumquat, Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

1.3$/ 1.3$/.85$

.15*/.14*/.09

N.A. / 38$/5.9$

N.A. /2.4$/.37*

N.A. / .05 / .03

10. Amaranth - Chinese, Broccoli (Unspecified,
Chinese, and Raab), Cabbage (Unspecified and
Chinese), Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard Cabbage (Gai
Choy/Pak-Choi), and Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

.13*/.13*/.09

.01/.01/.01

N.A. / 3.8$/.59$

N.A. / .24* / .04

N.A. / <01/<01

11. Corn (Unspecified, Field, Pop, and Sweet) and
Millet (Foxtail)

Air: 1.5
Other: 1.5

.11* / .11* / .07

.01/.01/.01

N.A. / 3.2$/.50*

N.A. / .20* / .03

N.A. / <01/<01

207


-------
Maximum

Dose-based Acute RQs for 3 Sizes (Small / Medium / Larue) of Terrestrial Phase CRLF

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Small Insects

Lar^c Insects

Small Herbivore
Mammals

Small Inscctivorc
Mammals

Small Terrestrial
Phase
Amphibian

12. Cotton

Air: 4
Other: 4

.40*/.39*/.26*

.04 / .04 / .03

N.A. / 11$ / 1.8$

N.A./.71$/.ll*

N.A./.01/.01

15. Apricot

Air: 10
Other: 10

.56$/.55$/.36*

.06 / .06 / .04

N.A. / 16$ / 2.5$

N.A. / 1.0$/.16*

N.A./.02/.01

16. Nectarine and Peach

Air: 9
Other: 9

.51$/.50*/.33*

.06 / .06 / .04

N.A. / 14$/2.2$

N.A./.9$/.14*

N.A. / .02 / .01

17. Cherry

Air: 8
Other: 8

.47*/.46*/.30*

.05 / .05 / .03

N.A. / 13$/2.1$

N.A./.84$/.13*

N.A./.02/.01

18. Fig

Air: 2.5
Other: 2.5

.14*/.14*/.09

.02/.02/.01

N.A. / 4.1$/.63$

N.A. / .25* / .04

N.A. / <01/<01

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

.07 / .07 / .05
.09 / .09 / .06

.01/.01/.01
.01/.01/.01

N.A. / 2.1$/.33*
N.A. / 2.5$/.39*

N.A./.13*/.02
N.A./.16*/.02

N.A. / <01/<01
N.A. / <01/<01

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

.04 / .04 / .03
.09 / .09 / .06

<01/<01/<01
.01/.01/.01

N.A. / 1.3$/.20*
N.A. / 2.5$/.39*

N.A./.08/.01
N.A./.16*/.02

N.A. / <01/<01
N.A. / <01/<01

21. Papaya

Air: .175
Other: .175

.01/.01/.01

<01/ <01/ <01

N.A. / .30* / .05

N.A./.02/<01

N.A. /<01/<01

22. Garlic and Leek

Air: 2
Other: 2

.11*/.10*/.07

.01/.01/.01

N.A./30$/.47*

N.A. /.19*/.03

N.A. /<01/<01

23. Grapes

Air: 2.75
Other: 27.47

.13*/.12*/.08
1.3$/ 1.2$/.82$

.01/.01/.01
.14*/.14*/.09

N.A. / 3.6$/.56$
N.A. / 36$/5.6$

N.A./.23*/.04
N.A. / 2.3$/.35*

N.A. / <01/<01
N.A. / .04 / .03

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

.12*/.12*/.08

.01/.01/.01

N.A. / 3.5$/.55$

N.A. / .22* / .03

N.A. / <01/<01

27. Swiss Chard, Chervil, Endive (Escarole),
Lettuce, Head Lettuce, Leaf Lettuce (Black
Seeded Simpson, Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley, Roquette (Arrugula),
Salsify, and Spinach

Air: 2
Other: 2

.13*/.13*/.08

.01/.01/.01

N.A. / 3.7$/.58$

N.A./.23*/.04

N.A. / <01/<01

28. Peppermint

Air: 1
Other: 1

.05 / .05 / .03

.01/. 01/ <01

N.A. / 1.4$/.22*

N.A./.09/.01

N.A. /<01/<01

29. Eggplant

Air: 3.5
Other: 3.5

.23*/.22*/.14*

.03 / .02 / .02

N.A. / 6.4$/1.0$

N.A. / .4* / .06

N.A./.01/.01

208


-------


Maximum

Dose-based Acute RQs for 3 Sizes (Small / Medium / Larue) of Terrestrial Phase CRLF

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Small Insects

Large Insects

Small Herbivore
Mammals

Small Inscctivorc
Mammals

Small Terrestrial
Phase
Amphibian

30. Pumpkin

Air: 2
Other: 2

.12*/.12*/.08

.01/.01/.01

N.A. / 3.3$ / .52$

N.A. /.21*/.03

N.A. / <01/<01

31. Cucumber, Cucurbit Vegetables, Melons -
Unspecified, Cantaloupe, Honeydew, Musk,
Water, and Winter

(Casaba/Crenshaw/Honeydew/Persian), and
Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

.11* / .11* / .07

.01/.01/.01

N.A. / 3.1$ / .49*

N.A. / .20* / .03

N.A. / <01/<01

32. Onion (Unspecified and Green), Radish, and
Shallot

Air: 2
Other: 2

.11*/.10*/.07

.01/.01/.01

N.A. / 3.0$/.47*

N.A. /.19*/.03

N.A. / <01/<01

33. Potato - White/Irish

Air: 3
Other: 3

.16*/.16*/.10*

.02/.02/.01

N.A./4.5$/.70$

N.A. / .28* / .04

N.A./.01/<01

34. Turnip

Air: 2.5
Other: 2.5

.13*/.13*/.09

.01/.01/.01

N.A. / 3.8$/.59$

N.A. / .24* / .04

N.A. / <01/<01

35. Parsnip and Rutabaga

Air: 2
Other: 2

.11*/.10*/.07

.01/.01/.01

N.A. / 3.0$/.47*

N.A. /.19*/.03

N.A. / <01/<01

36. Sweet Potato

Air: 1.875
Other: 1.875

.08 / .08 / .05

.01/.01/.01

N.A. / 2.4$/.37*

N.A./.15*/.02

N.A. /<01/<01

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas (Including
Vines), Rangeland, Sudangrass, and Timothy

Air: 1.25
Other: 1.25

.10*/.10*/.07

.01/.01/.01

N.A. / 3.0$/.46*

N.A. /. 19*/.03

N.A. / <01/<01

40. Beets, Cowpea/Blackeyed Pea, and Peas
(Unspecified and Field)

Air: 2.5
Other: 2.5

.13*/.13*/.09

.01/.01/.01

N.A. / 3.8$/.59$

N.A. / .24* / .04

N.A. / <01/<01

41. Carrot (Including Tops), Celtuce, Fennel, and
Pepper

Air: 2
Other: 2

.13*/.13*/.09

.01/.01/.01

N.A. / 3.8$/.59$

N.A. / .24* / .04

N.A. / <01/<01

42. Beans, Beans - Dried-Type, Beans - Succulent
(Lima), and Beans - Succulent (Snap)

Air: 1.75
Other: 1.75

.09 / .09 / .06

.01/.01/.01

N.A. / 2.6$/.41*

N.A. /. 17*/.03

N.A. /<01/<01

43. Celery

Air: 1.5
Other: 1.5

.07 / .07 / .04

.01 / .01 / <01

N.A. / 1.9$/.30*

N.A./.12*/.02

N.A. /<01/<01

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

.07 / .07 / .04

.01 / .01 / <01

N.A. / 1.9$/.30*

N.A./.12*/.02

N.A. /<01/<01

45. Anise

Air: .9375
Other: .9375

.05 / .05 / .03

.01 / .01 / <01

N.A. / 1.4$/.22*

N.A./.09/.01

N.A. /<01/<01

209


-------
Maximum

Dose-based Acute RQs for 3 Sizes (Small / Medium / Large) of Terrestrial Phase CRLF

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Small Insects

Large Insects

Small Herbivore
Mammals

Small Inscctivorc
Mammals

Small Terrestrial
Phase
Amphibian

46. Strawberry

Air: 2
Other: 2

.12*/.12*/.08

.01/.01/.01

N.A. / 3.3$ / .52$

N.A. /.21*/.03

N.A. / <01/<01

47. Sugar Beet

Air: 1.875
Other: 1.875

.10/.10/.06

.01/.01/.01

N.A. / 2.8$ / .44*

N.A./.18*/.03

N.A. /<01/<01

48. Tomato

Air: 3.5
Other: 3.5

.23*/.22*/.14*

.03 / .02 / .02

N.A. / 6.4$/1.0$

N.A. / .40* / .06

N.A./.01/.01

49. Okra

Air: 1.5
Other: 1.5

.09 / .09 / .06

.01/.01/.01

N.A. / 2.5$/.39*

N.A./.16*/.02

N.A. /<01/<01

51. Sorghum

Air: 1.5
Other: 1.5

.07 / .07 / .05

.01/.01/.01

N.A. / 2.1$/.33*

N.A./.13*/.02

N.A. /<01/<01

52. Barley, Cereal Grains, Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

.06 / .06 / .04

.01 / .01 / 0

N.A. / 1.8$/.28*

N.A./.II*/.02

N.A. / <01/<01

53. Gooseberry

Air: 16
Other: 16

.90$/.89$/.58$

.10*/.10/.06

N.A. / 26$/4.0$

N.A. / 1.6$/.25*

N.A. / .03 / .02

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

.23*/.22*/.15*

.03 / .02 / .02

N.A. / 6.4$/1.0$

N.A. / .40* / .06

N.A./.01/.01

55. Blueberry

Air: 2.5
Other: 2.5

.17*/.17*/.11*

.02/.02/.01

N.A./4.9$/.76$

N.A./.31*/.05

N.A./.01/<01

56. Caneberries and Currant

Air: 2
Other: 2

.11* / .11* / .07

.01/.01/.01

N.A. / 3.2$/.50*

N.A. / .20* / .03

N.A. / <01/<01

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

.04 / .04 / .03

<01 / <01 / <01

N.A. / 1.3$/.20*

N.A./.08/.01

N.A. /<01/<01

58. Mint and Spearmint

Air: 1
Other: 1

.05 / .05 / .03

.01 / .01 / <01

N.A. / 1.4$/.22*

N.A./.09/.01

N.A. /<01/<01

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

.08 / .08 / .05

.01/.01/.01

N.A. /2.2$/.34*

N.A./.14*/.02

N.A. /<01/<01

61. Water Cress

Air: 2
Other: 2

.13*/.13*/.08

.01/.01/.01

N.A. / 3.7$/.57$

N.A./.23*/.04

N.A. / <01/<01

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine (Seed
Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

.14*/.13*/.09

.02/.01/.01

N.A. / 3.9$/.61$

N.A. / .24* / .04

N.A. / <01/<01

210


-------
Maximum

Dose-based Acute RQs for 3 Sizes (Small / Medium / Large) of Terrestrial Phase CRLF

Scenario Group:
Crop/Site

Application

Rates1
(Lbs. ai/A)

Small Insects

Large Insects

Small Herbivore
Mammals

Small Inscctivorc
Mammals

Small Terrestrial
Phase
Amphibian

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs (with
Human or Wildlife Use), Lakes/Ponds/Reservoirs
(without Human or Wildlife Use), Polluted Water,
and Swamps/Marshes/Wetlands/Stagnant Water

Air: .6
Other: .6

.03 / .03 / .02

<01/<01/<01

N.A. / .75$ / .12*

N.A./.05/.01

N.A. /<01/<01

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

.14*/.14*/.09

.02/.02/.01

N.A. / 4.1$ / .64$

N.A. / .26* / .04

N.A. / <01/<01

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use), Urban
Areas, and Wide Area/General Outdoor Treatment
(Public Health Use)

Air: .6119
Other: .1361

.03 / .03 / .02
.01/.01/<01

<01/ <01/ <01
<01/ <01/ <01

N.A./.94$/.15*
N.A. /.21*/.03

N.A./.06/.01
N.A. / .01 / < 01

N.A. / <01/<01
N.A. / <01/<01

Residential. Household/Domestic Dwellings
Outdoor Premises, Ornamental and/or Shade
Trees, Ornamental Herbaceous Plants, Ornamental
Lawns and Turf, Ornamental Non-flowering
Plants, Ornamental Woody Shrubs and Vines, and
Urban Areas

Other: ,253

.01/.01/.01

<01/ <01/ <01

N.A. / .39* / .06

N.A./.02/<01

N.A. /<01/<01

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

.04 / .04 / .03

<01 / <01 / <01

N.A. / 1.1$/. 18*

N.A./.07/.01

N.A. /<01/<01

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

.05 / .05 / .04

.01/. 01/ <01

N.A. / 1.6$/.24*

N.A./. 10/.02

N.A. /<01/<01

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

* Acute RQ > 0.1 for listed species.

$ Acute RQ > 0.5 for listed and non-listed species.

211


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5.2.2 Indirect Effects via Reduction in Food Items

5.2.2.1 Aquatic Phase Frog- Fish as Prey

The evaluation of acute and chronic risks to freshwater fish (a potential prey of frogs in
the aquatic environment) revealed that malathion acute fish RQs exceeded the non-listed
species acute LOC in 58 of 68 aerial and air-blast application scenarios and 29 of 68
scenarios involving other application methods. In addition, consultation for the RQ table
for fish reveals that 50 of the 68 use sites assessed produced RQ values of 1 or greater,
suggesting that exposures could produce 50% or greater mortality in sensitive fish
populations.

However it must be noted that the endpoint selected for RQ calculation was the most
sensitive acute endpoint for the tested species rainbow trout) and other higher endpoints
were available for this species as well as a large variety of other fish. If this or other
species are not truly affected at levels suggested by the conservative RQ approach, it
would be likely that adequate fish prey resources may still be available to a generalist
feeder such as the CRLF. A review of the available acute effects data in this assessment
reveals that endpoints for other fish are between 5 and 11,000 times less sensitive than
the rainbow trout endpoint used in RQ calculations. Because this range reflects a large
number of alternative tested species (N=44) additional analysis considering this robust
distribution of endpoints was undertaken to see if malathion exposures would produce
acute risks of concern for additional species. For every species with one or more 96-h
LC50 endpoints reported in the effects section of this document, either a measured value
or the geometric mean of 2 or more values was assigned. This suite of acute endpoints
was then adjusted downward by a factor of 2 to correspond with the Agency non-listed
species acute concern level and then compared with the EECs available from acute
aquatic residue estimates for all use scenarios. Table 44 presents the results of the
comparison, which suggest that the RQ approach employed in the risk assessment may be
unduly conservative for many use sites. In most cases only a small percentage of effect
endpoints were exceeded by the EECs estimated for malathion use sites. Assuming that
the distribution of tested species endpoints approximates the distribution of
sensitivities of fish in CRLF habitats, it is unlikely that substantial number of fish
species would be significantly affected by malathion residues in the water (NLAA
for CRLF), except for the following uses: pecan and walnuts, avocados, citrus,
apricots, gooseberries, rice, watercress, forestry, and mosquito control. Therefore,
there appears to be sufficient evidence to support a finding that acute effects are
likely to result in significant impairment of fish prey (LAA for CRLF) for the
following uses: pecan and walnuts, avocados, citrus, apricots, gooseberries, rice,
watercress, forestry, and mosquito control.

212


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Table 44. Results of Acute Malathion EECs Compared with Distribution of Fish LCS0 Values
Adjusted for Acute Non-Listed Species LOC.				

Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Peak EEC

(jig/L)

Maximum
Number of
Fish LC;(/2

Values
Exceeded

Percentage of
Tested Fish

Species
Significantly
Affected

A

gricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine,
Trefoil, and Vetch

Air: 2
Other: 2

9.6
5.3

1

2.3

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

52
13

2

4.5

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

43
8.6

8

18

4. Chestnut

Air: 5
Other: 5

16

3.3

2

4.5

5. Almond

Air: 1.25
Other: 4

7.4
13

0

0

6. Date

Air: 1
Other: 2

2.9
1.1

0

0

7. Filbert (Hazelnut)

Air: .625
Other: .625

2.1
.43

0

0

8. Avocado

Air: 9
Other: 9

31
6.1

5

11

9. Citrus, Citrus Hybrids other than Tangelo,
Grapefruit, Kumquat, Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

97
20

12

27

10. Amaranth - Chinese, Broccoli
(Unspecified, Chinese, and Raab), Cabbage
(Unspecified and Chinese), Canola\Rape,
Cauliflower, Collards, Corn Salad, Dock
(Sorrel), Horseradish, Kale, Kohlrabi,
Mustard, Mustard Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden and Winter)

Air: 2.5
Other: 2.5

8.9
1.8

1

2.3

11. Corn (Unspecified, Field, Pop, and
Sweet) and Millet (Foxtail)

Air: 1.5
Other: 1.5

7.9
1.6

0

0

12. Cotton

Air: 4
Other: 4

20
5.2

2

4.5

15. Apricot

Air: 10
Other: 10

34
6.8

6

14

16. Nectarine and Peach

Air: 9
Other: 9

29
5.9

4

9

17. Cherry

Air: 8
Other: 8

29
5.8

4

9

18. Fig

Air: 2.5
Other: 2.5

8.5
1.7

1

2.3

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

4.1
.98

0

0

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

2.8
.56

0

0

21. Papaya

Air: .175
Other: .175

.65
.13

0

0

22. Garlic and Leek

Air: 2
Other: 2

9.9
5.9

1

2.3

213


-------
Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Peak EEC

(jig/L)

Maximum
Number of
Fish LC;./2

Values
Exceeded

Percentage of
Tested Fish

Species
Significantly
Affected

23. Grapes

Air: 2.75
Other: 27.47

9
18

1

2.3

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

9.1
1.8

1

2.3

27. Swiss Chard, Chervil, Endive (Escarole),
Lettuce, Head Lettuce, Leaf Lettuce (Black
Seeded Simpson, Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley, Roquette
(Arrugula), Salsify, and Spinach

Air: 2
Other: 2

20
14

2

4.5

28. Peppermint

Air: 1
Other: 1

3.6
.73

0

0

29. Eggplant

Air: 3.5
Other: 3.5

12
2.5

1

2.3

30. Pumpkin

Air: 2
Other: 2

6.9
1.4

0

0

31. Cucumber, Cucurbit Vegetables, Melons
- Unspecified, Cantaloupe, Honeydew,
Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persian), and
Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

6.5
1.7

0

0

32. Onion (Unspecified and Green), Radish,
and Shallot

Air: 2
Other: 2

7.9
3.2

0

0

33. Potato - White/Irish

Air: 3
Other: 3

9.8
2

1

2.3

34. Turnip

Air: 2.5
Other: 2.5

8.5
1.7

1

2.3

35. Parsnip and Rutabaga

Air: 2
Other: 2

6.1

1.2

0

0

36. Sweet Potato

Air: 1.875
Other: 1.875

5.9
1.2

0

0

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland, Sudangrass,
and Timothy

Air: 1.25
Other: 1.25

8.5
1.7

1

2.3

40. Beets, Cowpea/Blackeyed Pea, and Peas
(Unspecified and Field)

Air: 2.5
Other: 2.5

8.9
1.8

1

2.3

41. Carrot (Including Tops), Celtuce, Fennel,
and Pepper

Air: 2
Other: 2

8.3
1.7

1

2.3

42. Beans, Beans - Dried-Type, Beans -
Succulent (Lima), and Beans - Succulent
(Snap)

Air: 1.75
Other: 1.75

6.5
1.3

0

0

43. Celery

Air: 1.5
Other: 1.5

9.5

6.3

1

2.3

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

9

6.9

1

2.3

45. Anise

Air: .9375
Other: .9375

3.3
.67

0

0

46. Strawberry

Air: 2
Other: 2

7.8
1.6

0

0

214


-------
Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Peak EEC
(Ug/L)

Maximum
Number of
Fish LC;./2

Values
Exceeded

Percentage of
Tested Fish

Species
Significantly
Affected

47. Sugar Beet

Air: 1.875
Other: 1.875

10
4.8

1

2.3

48. Tomato

Air: 3.5
Other: 3.5

12
2.4

1

2.3

49. Okra

Air: 1.5
Other: 1.5

5.1
1

0

0

51. Sorghum

Air: 1.5
Other: 1.5

4.6

.93

0

0

52. Barley, Cereal Grains, Oats, Rye, and
Wheat

Air: 1.25
Other: 1.25

12
8.7

1

2.3

53. Gooseberry

Air: 16
Other: 16

61
12

9

20

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

15

3

2

4.5

55. Blueberry

Air: 2.5
Other: 2.5

11

2.3

1

2.3

56. Caneberries and Currant

Air: 2
Other: 2

7.6
1.5

0

0

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

2.9
.58

0

0

58. Mint and Spearmint

Air: 1
Other: 1

3.4
.68

0

0

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

1404

26

59

61. Water Cress

Air: 2
Other: 2

1797

27

61

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine
(Seed Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

56
50

9

20

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs (without Human or
Wildlife Use), Polluted Water, and
Swamps/Marshes/Wetlands/Stagnant Water

Air: .6
Other: .6

539

19

43

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

8.7
1.7

1

2.3

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use),
Urban Areas, and Wide Area/General
Outdoor Treatment (Public Health Use)

Air: .6119
Other: .1361

15

3

2

4.5

Residential. Household/Domestic Dwellings
Outdoor Premises, Ornamental and/or Shade
Trees, Ornamental Herbaceous Plants,
Ornamental Lawns and Turf, Ornamental
Non-flowering Plants, Ornamental Woody
Shrubs and Vines, and Urban Areas

Other: ,253

.18

0

0

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and
Nonagricultural Uncultivated Areas/Soils

Air: .9281
Other: .9281

3

.59

0

0

215


-------
Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Peak EEC

(jig/L)

Maximum
Number of
Fish LC;„/2

Values
Exceeded

Percentage of
Tested Fish

Species
Significantly
Affected

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

4
.8

0

0

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift
when estimating environmental concentrations. "Other" refers other application methods for which EFED
policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from
2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does
not assume the same parcels are re-treated each weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25
lbs. ai/A.

The assessment of food supply impacts also extends to chronic risks to aquatic
invertebrates. Extrapolated NOAEC values for each acute toxicity endpoint from above
can be estimated by dividing by the ACR value of 40.6 as for the RQ calculations. While
there is considerable uncertainty in using a uniform ACR for all species, it does allow for
an evaluation of the number and percent of tested fish species that would potentially be at
reproduction risks when exposed to malathion at EEC levels. Table 45 shows the results
of this comparison. In Table 45 use scenarios, a substantial number of tested species
could be at reproduction risk. The chronic EECs for another 22 scenarios do not trigger
concerns for many species ( alfalfa etal. almonds, dates, filberts, corn, figs, guava et al.,
papaya, grapes, peppermint, parsnip/rutabaga, sweet potato, bluegrass et al., beans,
celery, anise, okra, sorghum, passion fruit, mint/spearmint, residential ornamental and
lawn, and rights of ways). For uses other than those listed above, the effects
determination is that the labeled uses are likely to adversely affect (LAA)
individuals of the species through impairment of the invertebrate food supply
through chronic toxic effects (LAA). However, for alfalfa et al., almonds, dates,
filberts, corn, figs, guava et al., papaya, grapes, peppermint, parsnip/rutabaga,
sweet potato, bluegrass et al., beans, celery, anise, okra, sorghum, passion fruit,
mint/spearmint, residential ornamental and lawn, and rights of ways the effects
determination is NLAA.

Table 45. Results of Chronic Malathion EECs Compared with a Distribution of Fish NOAEC Values
Adjusted for Acute Non-Listed Species LOC.				

Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Chronic

EEC

(USI/L)

Maximum
Number of
Fish NO AC
Values
Exceeded

Percentage of
Tested Fish

Species
Significantly
Affected

A

gricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine,
Trefoil, and Vetch

Air: 2
Other: 2

1.4
.58

3

7

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

18
3.8

19

43

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

6.5
1.3

15

34

216


-------


Maximum



Maximum

Percentage of



Malathion



Number of

Tested Fish



Application

Chronic

Fish NOAC

Species



Rates1

EEC

Values

Significantly

Scenario Group: Crop/Site

(Lbs. ai/A)

(jig/L)

Exceeded

Affected

4. Chestnut

Air: 5
Other: 5

3.5
.7

9

20

5. Almond

Air: 1.25
Other: 4

1.3
1.9

3

7

6. Date

Air: 1

.52

1



Other: 2

.21

L

7. Filbert (Hazelnut)

Air: .625
Other: .625

.32
.066

0

0

8. Avocado

Air: 9
Other: 9

3.3
.66

9

20

9. Citrus, Citrus Hybrids other than Tangelo,
Grapefruit, Kumquat, Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

17
3.5

19

43

10. Amaranth - Chinese, Broccoli









(Unspecified, Chinese, and Raab), Cabbage
(Unspecified and Chinese), Canola\Rape,
Cauliflower, Collards, Corn Salad, Dock

Air: 2.5
Other: 2.5

3.2

.63

6

14

(Sorrel), Horseradish, Kale, Kohlrabi,





Mustard, Mustard Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden and Winter)









11. Corn (Unspecified, Field, Pop, and
Sweet) and Millet (Foxtail)

Air: 1.5
Other: 1.5

.76
.15

2

5

12. Cotton

Air: 4
Other: 4

12
2.3

19

43

15. Apricot

Air: 10
Other: 10

6.5
1.3

15

34

16. Nectarine and Peach

Air: 9
Other: 9

5.2
1

13

30

17. Cherry

Air: 8
Other: 8

8.1
1.6

17

39

18. Fig

Air: 2.5
Other: 2.5

1

.21

2

5

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

1.7
.41

6

14

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

1.3
.27

3

7

21. Papaya

Air: .175
Other: .175

.31
.063

0

0

22. Garlic and Leek

Air: 2
Other: 2

2

.61

8

18

23. Grapes

Air: 2.75
Other: 27.47

.87
1.7

2

5

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

1.7
.34

6

14

27. Swiss Chard, Chervil, Endive (Escarole),









Lettuce, Head Lettuce, Leaf Lettuce (Black
Seeded Simpson, Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley, Roquette
(Arrugula), Salsify, and Spinach

Air: 2
Other: 2

3.5
1.5

9

20

217


-------
Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Chronic

EEC
(jig/L)

Maximum
Number of
Fish NOAC

Values
Exceeded

Percentage of
Tested Fish

Species
Significantly
Affected

28. Peppermint

Air: 1
Other: 1

.68
.14

2

5

29. Eggplant

Air: 3.5
Other: 3.5

2.6
.61

9

20

30. Pumpkin

Air: 2
Other: 2

1.8

.39

6

14

31. Cucumber, Cucurbit Vegetables, Melons
- Unspecified, Cantaloupe, Honeydew,
Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persian), and
Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

1.8
.4

6

14

32. Onion (Unspecified and Green), Radish,
and Shallot

Air: 2
Other: 2

2.3
.55

8

18

33. Potato - White/Irish

Air: 3
Other: 3

2.4
.48

8

18

34. Turnip

Air: 2.5
Other: 2.5

2.3
.46

8

18

35. Parsnip and Rutabaga

Air: 2
Other: 2

1.3
.26

3

7

36. Sweet Potato

Air: 1.875
Other: 1.875

.61
.13

1

2

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland, Sudangrass,
and Timothy

Air: 1.25
Other: 1.25

.77
.16

2

5

40. Beets, Cowpea/Blackeyed Pea, and Peas
(Unspecified and Field)

Air: 2.5
Other: 2.5

2.7
.53

9

20

41. Carrot (Including Tops), Celtuce, Fennel,
and Pepper

Air: 2
Other: 2

2.9
.58

9

20

42. Beans, Beans - Dried-Type, Beans -
Succulent (Lima), and Beans - Succulent
(Snap)

Air: 1.75
Other: 1.75

1.1
.22

2

5

43. Celery

Air: 1.5
Other: 1.5

1

.53

2

5

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

3.2
1.2

9

20

45. Anise

Air: .9375
Other: .9375

1.4
.27

3

7

46. Strawberry

Air: 2
Other: 2

2.7
.53

9

20

47. Sugar Beet

Air: 1.875
Other: 1.875

2.3
.69

8

18

48. Tomato

Air: 3.5
Other: 3.5

2.4
.48

8

18

49. Okra

Air: 1.5
Other: 1.5

1.3
.27

3

7

51. Sorghum

Air: 1.5
Other: 1.5

.63
.13

2

5

52. Barley, Cereal Grains, Oats, Rye, and
Wheat

Air: 1.25
Other: 1.25

1.8
1.1

6

14

218


-------
Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Chronic

EEC
(jig/L)

Maximum
Number of
Fish NOAC

Values
Exceeded

Percentage of
Tested Fish

Species
Significantly
Affected

53. Gooseberry

Air: 16
Other: 16

14
2.7

19

43

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

3.4
.68

9

20

55. Blueberry

Air: 2.5
Other: 2.5

2.1
.42

8

18

56. Caneberries and Currant

Air: 2
Other: 2

1.7
.34

6

14

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

1.3
.25

3

7

58. Mint and Spearmint

Air: 1
Other: 1

.57
.12

1

2

59. Rice and Wild Rice

Air: 1.5625

110

28

64

61. Water Cress

Air: 2

141

32

73

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine
(Seed Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

6.5
4.7

15

34

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs (without Human or
Wildlife Use), Polluted Water, and
Swamps/Marshes/Wetlands/Stagnant Water

Air: .6

42

21

48

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

2
.4

8

18

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use),
Urban Areas, and Wide Area/General
Outdoor Treatment (Public Health Use)

Air: .6119
Other: .1361

3.7
.61

9

20

Residential. Household/Domestic Dwellings
Outdoor Premises, Ornamental and/or Shade
Trees, Ornamental Herbaceous Plants,
Ornamental Lawns and Turf, Ornamental
Non-flowering Plants, Ornamental Woody
Shrubs and Vines, and Urban Areas

Other: ,253

.096

0

0

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and
Nonagricultural Uncultivated Areas/Soils

Air: .9281
Other: .9281

.62
.12

1

2

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

1.6

.33

6

14

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift
when estimating environmental concentrations. "Other" refers other application methods for which EFED
policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from
2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does
not assume the same parcels are re-treated each weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25
lbs. ai/A.

219


-------
5.2.2.2 Aquatic Phase Frog- Invertebrates as Prey

The freshwater invertebrate acute RQ values for all uses are well in excess of the level of
concern and orders of magnitude in excess of the median lethal concentration endpoint
used in the risk assessment. This would suggest that mortality levels, regardless of the
slope of the dose response function for the tested species, are in excess of 50% for this
species. Exploration of the available data summarized in the effects section of this
document reveals that 79 species of aquatic invertebrates are represented. A distribution
of effects endpoints was established and a comparison of these data, adjusted to reflect
the non-listed species acute effects concern level (endpoint/2), with acute EECs is
summarized in Table 46 in only one use scenario (residential ornamental and lawn) did
the acute EEC exceed a small number of tested species acute effects endpoints adjusted to
the acute risk LOC. In all other cases substantial percentages of tested species endpoint
were exceeded, suggesting that for all these uses (except residential ornamental and lawn)
there is likely to be impairment of the invertebrate prey base for the frog.

Table 46. Results of Acute Malathion EECs Compared with Distribution of invertebrate LCS0 Values
Adjusted for Acute Non-Listed Species LOC.				









Percentage of



Maximum



Maximum

Tested



Malathion



Number of

Invertebrate



Application
Rates1

Peak EEC

Invertebrate
LC;„/2 Values

Species
Significantly

Scenario Group: Crop/Site

(Lbs. ai/A)

(Utl/L)

Exceeded

Affected

Agricultural Uses

1. Alfalfa, Clover, Lespedeza, Lupine,
Trefoil, and Vetch

Air: 2
Other: 2

9.6
5.3

26

36

2. Macadamia Nut (Bushnut)

Air: 15
Other: 15

52
13

50

68

3. Pecan and Walnut (English/Black)

Air: 12.5
Other: 12.5

43
8.6

49

67

4. Chestnut

Air: 5
Other: 5

16

3.3

32

44

5. Almond

Air: 1.25
Other: 4

7.4
13

26

36

6. Date

Air: 1
Other: 2

2.9
1.1

22

30

7. Filbert (Hazelnut)

Air: .625
Other: .625

2.1
.43

20

27

8. Avocado

Air: 9
Other: 9

31
6.1

43

59

9. Citrus, Citrus Hybrids other than
Tangelo, Grapefruit, Kumquat, Lemon,
Lime, Orange, Tangelo, and Tangerines

Air: 25
Other: 25

97
20

55

75

220


-------
Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Peak EEC

(Hg/L)

Maximum
Number of
Invertebrate
LC;„/2 Values
Exceeded

Percentage of

Tested
Invertebrate

Species
Significantly
Affected

10. Amaranth - Chinese, Broccoli
(Unspecified, Chinese, and Raab),

Cabbage (Unspecified and Chinese),
Canola\Rape, Cauliflower, Collards, Corn
Salad, Dock (Sorrel), Horseradish, Kale,
Kohlrabi, Mustard, Mustard Cabbage (Gai
Choy/Pak-Choi), and Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

8.9
1.8

26

36

11. Corn (Unspecified, Field, Pop, and
Sweet) and Millet (Foxtail)

Air: 1.5
Other: 1.5

7.9
1.6

26

36

12. Cotton

Air: 4
Other: 4

20
5.2

34

47

15. Apricot

Air: 10
Other: 10

34
6.8

46

63

16. Nectarine and Peach

Air: 9
Other: 9

29
5.9

43

59

17. Cherry

Air: 8
Other: 8

29
5.8

43

59

18. Fig

Air: 2.5
Other: 2.5

8.5
1.7

26

36

19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

4.1
.98

23

32

20. Guava, Mango, Plum, and Prune

Air: .75
Other: 1.5

2.8
.56

22

30

21. Papaya

Air: .175
Other: .175

.65
.13

9

12

22. Garlic and Leek

Air: 2
Other: 2

9.9
5.9

26

36

23. Grapes

Air: 2.75
Other: 27.47

9
18

26

36

26. Brussel Sprouts and Dandelion

Air: 2.5
Other: 2.5

9.1
1.8

26

36

27. Swiss Chard, Chervil, Endive
(Escarole), Lettuce, Head Lettuce, Leaf
Lettuce (Black Seeded Simpson, Salad
Bowl, Etc.), Orach (Mountain Spinach),
Parsley, Roquette (Arrugula), Salsify, and
Spinach

Air: 2
Other: 2

20
14

34

47

28. Peppermint

Air: 1
Other: 1

3.6
.73

23

32

29. Eggplant

Air: 3.5
Other: 3.5

12
2.5

28

38

30. Pumpkin

Air: 2
Other: 2

6.9
1.4

26

36

31. Cucumber, Cucurbit Vegetables,
Melons - Unspecified, Cantaloupe,
Honey dew, Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persian),
and Squash (All Or Unspecified)

Air: 1.875
Other: 1.875

6.5
1.7

26

36

221


-------
Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Peak EEC

(Hg/L)

Maximum
Number of
Invertebrate
LC;„/2 Values
Exceeded

Percentage of

Tested
Invertebrate

Species
Significantly
Affected

32. Onion (Unspecified and Green),
Radish, and Shallot

Air: 2
Other: 2

7.9
3.2

26

36

33. Potato - White/Irish

Air: 3
Other: 3

9.8
2

26

36

34. Turnip

Air: 2.5
Other: 2.5

8.5
1.7

26

36

35. Parsnip and Rutabaga

Air: 2
Other: 2

6.1

1.2

26

36

36. Sweet Potato

Air: 1.875
Other: 1.875

5.9
1.2

25

34

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland, Sudangrass,
and Timothy

Air: 1.25
Other: 1.25

8.5
1.7

26

36

40. Beets, Cowpea/Blackeyed Pea, and
Peas (Unspecified and Field)

Air: 2.5
Other: 2.5

8.9
1.8

26

36

41. Carrot (Including Tops), Celtuce,
Fennel, and Pepper

Air: 2
Other: 2

8.3
1.7

26

36

42. Beans, Beans - Dried-Type, Beans -
Succulent (Lima), and Beans - Succulent
(Snap)

Air: 1.75
Other: 1.75

6.5
1.3

26

36

43. Celery

Air: 1.5
Other: 1.5

9.5

6.3

26

36

44. Asparagus and Safflower (Unspecified)

Air: 1.25
Other: 1.25

9

6.9

26

36

45. Anise

Air: .9375
Other: .9375

3.3
.67

22

30

46. Strawberry

Air: 2
Other: 2

7.8
1.6

26

36

47. Sugar Beet

Air: 1.875
Other: 1.875

10
4.8

26

36

48. Tomato

Air: 3.5
Other: 3.5

12
2.4

28

38

49. Okra

Air: 1.5
Other: 1.5

5.1
1

25

34

51. Sorghum

Air: 1.5
Other: 1.5

4.6

.93

24

33

52. Barley, Cereal Grains, Oats, Rye, and
Wheat

Air: 1.25
Other: 1.25

12
8.7

28

38

53. Gooseberry

Air: 16
Other: 16

61
12

52

71

54. Blackberry, Boysenberry, Dewberry,
Loganberry, and Raspberry (Black - Red)

Air: 4
Other: 4

15

3

30

41

55. Blueberry

Air: 2.5
Other: 2.5

11

2.3

26

36

56. Caneberries and Currant

Air: 2
Other: 2

7.6
1.5

26

36

57. Passion Fruit (Granadilla)

Air: .75
Other: .75

2.9
.58

22

30

222


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Scenario Group: Crop/Site

Maximum
Malathion
Application

Rates1
(Lbs. ai/A)

Peak EEC

(Hg/L)

Maximum
Number of
Invertebrate
LC;„/2 Values
Exceeded

Percentage of

Tested
Invertebrate

Species
Significantly
Affected

58. Mint and Spearmint

Air: 1
Other: 1

3.4
.68

22

30

59. Rice and Wild Rice

Air: 1.5625
Other: 1.5625

1404

70

96

61. Water Cress

Air: 2
Other: 2

1797

71

97

Non-agricultural Uses

Forestry. Christmas Tree Plantations, Pine
(Seed Orchard), and Slash Pine (Forest)

Air: 3.2
Other: 3.2

56
50

52

71

Mosquito Control. Intermittently Flooded
Areas/Water, Lakes/Ponds/Reservoirs
(with Human or Wildlife Use),
Lakes/Ponds/Reservoirs (without Human
or Wildlife Use), Polluted Water, and
Swamps/Marshes/W etlands/Stagnant
Water

Air: .6
Other: .6

539

66

90

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

8.7
1.7

26

36

Public Health and Medfly Control.

Nonagricultural Areas (Public Health Use),
Urban Areas, and Wide Area/General
Outdoor Treatment (Public Health Use)

Air: .6119
Other: .1361

15

3

30

41

Residential. Household/Domestic
Dwellings Outdoor Premises, Ornamental
and/or Shade Trees, Ornamental
Herbaceous Plants, Ornamental Lawns and
Turf, Ornamental Non-flowering Plants,
Ornamental Woody Shrubs and Vines, and
Urban Areas

Other: ,253

.18

1

1

Rights-of-way. Nonagricultural Rights-of-
way/Fencerows/Hedgerows and
Nonagricultural Uncultivated Areas/Soils

Air: .9281
Other: .9281

3

.59

22

30

Turf. Golf Course Turf (Bermudagrass)

Air: 1.25
Other: 1.25

4
.8

23

32

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift
when estimating environmental concentrations. "Other" refers other application methods for which EFED
policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from
2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does
not assume the same parcels are re-treated each weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25
lbs. ai/A.

Similar refined analyses could be performed for chronic effects to invertebrates and their
implications on prey availability for the frog. However, further refinement was concluded
to be unnecessary for the following reasons:

223


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•	Chronic effects data distributions would rely on a uniform application of
available ACR data and yield less certain results than already observed for acute
effects.

•	The very high magnitude of chronic risk quotients, up to 7 orders of magnitude in
excess of the chronic LOC, suggest that further refinement would not likely alter
the existing risk picture considering that the distribution of chronic effects and
chronic effects data would be essentially identical to the acute effects
distribution, just shifted toward greater sensitivity

•	The additional refinement of chronic effect risks would not alter risk concerns
given the conclusions reached for acute effects

The effects determination for indirect effects (acute and chronic toxic effects to the
invertebrate prey) on the CRLF is that such impairments are likely to adversely
affect individuals of the species (LAA).

5.2.3	Indirect Effects via Reduction in Habitat and/or Primary Productivity
(Freshwater Aquatic Plants)

The RQ values for aquatic plants only exceed the Agency LOC for listed unicellular
algae. This endpoint is commonly used as a lower limit screening tool for those
organisms with an obligate relationship with a particular plant species. In the case of the
CRLF, no such obligate relationship exists and the non-listed plant LOCs apply. In the
case of malathion and maloxon assessment, there are no RQs exceeding the non-listed
plant levels of concern. Consequently, the available information suggests no likely
adverse effects (NLAA) on the CRLF stemming from effects on aquatic plants.

5.2.4	Indirect Effects via Alteration in Terrestrial Plant Community (Riparian
Habitat)

No evidence of malathion producing field relevant plant effects at field relevant exposure
levels suggests no effects on terrestrial plants associated with labeled uses of malathion
and no effects for maloxon as well. Therefore there are no effects relative to the
CRLF.

5.2.5	Modification to Critical Habitat

Table 47. Effects Determination Summary for the Critical Habitat Impact Analysis.

Assessment Endpoint

Effects
Dctcrminati
on

Basis

Aquatic Phase PCEs (Aquatic Breeding Habitat and Aquatic Non-Breeding Habitat)

Alteration of channel/pond morphology or
geometry and/or increase in sediment
deposition within the stream channel or
pond: aquatic habitat (including riparian
vegetation) provides for shelter, foraging,
predator avoidance, and aquatic dispersal
for juvenile and adult CRLF.

No effect

Risk of malathion to plants assumed to
be negligible with no expected effects on
terrestrial vegetation and extremely
limited effects on aquatic vegetation that
would be pertinent only to obligate
animals.

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Assessment I'lmlpoini

1. Mi-els
l)i-U-rmin;ili

nit

Basis

Alteration in water chemistry/quality
including temperature, turbidity, and
oxygen content necessary for normal
growth and viability of juvenile and adult
CRLF and their food source.1

No effect

Risk of malathion to plants assumed to be
negligible based on presumed low
phytotoxicity and mode of action.

Alteration of other chemical characteristics
necessary for normal growth and viability
of CRLF and their food source.

Adverse
habitat
modificatio
n

RQs exceeded for acute and chronic
effects for CRLF and prey items
(invertebrates, fish, and aquatic phase
amphibians).

Reduction and/or modification of aquatic-
based food sources (e.g., algae) for pre-
metamorphs.

No effect

Aquatic plant effects are only at a level
critical for obligate animals, no habitat
modification relavent to the generalist
CRLF.

Terrestrial Phase PCEs (Upland Habitat and Dispersal Habitat)

Elimination and/or disturbance of upland
habitat; ability of habitat to support food
sources of CRLF: Upland areas within 200
ft of the edge of the riparian vegetation or
drip line surrounding aquatic and riparian
habitat that are comprised of grasslands,
woodlands, and/or wetland/riparian plant
species that provide the CRLF shelter,
forage, and predator avoidance

No effect

No effects expected for terrestrial plants.

Elimination and/or disturbance of dispersal
habitat: Upland or riparian dispersal habitat
within designated units and between
occupied locations within 0.7 mi of each
other that allow for movement between
sites including both natural and altered sites
which do not contain barriers to dispersal.

No effect

No effects expected for terrestrial plants.

Reduction and/or modification of food
sources for terrestrial phase juveniles and
adults.

Adverse
habitat
modificatio
n

Malathion poses acute and chronic risk to
prey items of the CRLF (terrestrial
invertebrates, mice, and terrestrial-phase
frogs).

Alteration of chemical characteristics
necessary for normal growth and viability
of juvenile and adult CRLF and their food
sources.

Adverse
habitat
modificatio
n

Malathion poses acute and chronic risk to
prey items of the CRLF (terrestrial
invertebrates, mice, and terrestrial-phase
frogs).

1 Physico-chemical water quality parameters such as salinity, pH, and hardness are not evaluated because
these processes are not biologically mediated and, therefore, are not relevant to the endpoints included in
this assessment.

When evaluating the significance of this risk assessment's direct/indirect and adverse
habitat modification effects determinations, it is important to note that pesticide
exposures and predicted risks to the CRLF and its resources (i.e., food and habitat) are
not expected to be uniform across the action area or uniform over time. Risks to the
CRLF and its resources are expected to decrease with increasing distance away from the
treated field or site of application because both spray drift through air and dilution with
downstream transport in surface water will cause the pesticide eposure to attenuate with
distance.

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For sites distant from the site of malathion application, the adverse effects may be
intermittent because malathion is not expected to persist in most environments and the
conditions that cause it to exceed LOCs (e.g., right wind direction, heavy rain
immediately after application, etc.) may occur infrequently. Theses sites may experience
long periods of recovery between exposures of sufficient magnitude to cause any adverse
effects.

For sites closer to the site of malathion application, adverse conditions would be expected
to be more severe, causing mortality to both the CRLF and to the prey items on which the
CRLF depends, and more frequent, providing little time to recover before adverse
conditions re-occur. Because malathion has many uses and most of those uses would
cause adverse effects, it is expected that malathion would cause a larger proportion of
sites to experience severe adverse effects at greater frequency than pesticides that have
fewer uses and less severe effects. Additionally, because malathion does have so many
uses, it is possible that some sites are impacted by multiple uses.

Evaluation of the implication of this non-uniform distribution of risk to the CRLF would
require information and assessment techniques that are not currently available. Examples
of such information and methodology required for this type of analysis would include the
following:

•	Enhanced information on the density and distribution of CRLF life stages within
specific recovery units and/or designated critical habitat within the action area.
This information would allow for extrapolation of the present risk assessment's
predictions of individual effects to the proportion of the population within the
geographical areas where those effects are predicted to occur. Additionally, such
population-specific information would allow for a more comprehensive
evaluation of the significance of potential resource impairment to individual
CRLF.

•	Quantitative information on prey base requirements for individual aquatic- and
terrestrial-phase CRLF. While existing information indicates the types of food
sources utilized by the frog, it does not establish minimal requirements to sustain
healthy individuals at varying life stages. Such information could be used to
establish biologically relevant thresholds of effects on the prey base and identify
geographical limits to those effect thresholds. This information could be used
together with the density data (discussed above) to characterize the likelihood of
adverse effects to individual CRLF.

•	Information on population responses of prey base organisms to malathion.
Currently, methodologies are limited to predicting exposures and likely levels of
direct mortality, growth, or reproductive impairment of prey base organisms
immediately following exposure to malathion. Potentially, more ecologically
relevant effects to the prey base (e.g., the degree to which repeated exposure
events and inherent demographic characteristics of the prey population limit the
extent to which prey resources may recover) can not currently be predicted. An
enhanced understanding of long-term prey responses to pesticide exposure would
allow for an estimate of the magnitude and duration of resource impairment to be

226


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made. Combining such an estimate with the information described above might
provide a more comprehensive prediction of effects to individual frogs and
potential modification to critical habitat.

227


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6. Uncertainties

Risk assessment, by its very nature, is not exact, and requires the risk assessor to make
assumptions regarding a number of parameters, to use data which may or may not
accurately reflect the species of concern, and to use models which are a simplified
representation of complex ecological processes. In this risk assessment, EFED has
attempted to locate the best available data regarding such important parameters as the life
history of the CRLF, typical environmental conditions in the proximity of the CRLF's
habitat, toxicity of malathion and maloxon, and usage of malathion in the action area.
Frequently, such information is better expressed as ranges rather then points, and when
this is the case, EFED typically opts to use the end of range which would result in the
highest estimate of risk in order to ensure protection of the CRLF and its habitat. These
uncertainties, and the directions in which they may bias the risk estimate, are described
below.

6.1 Exposure Assessment Uncertainties

Typically, the uncertainties inherent in the exposure assessment tend to result in over-
estimation of exposures. In many assessments, this is apparent when comparing modeling
results with monitoring data. In particular, estimated peak exposures are generally an
order of magnitude above 90th percentile site concentrations in non-targeted surface water
monitoring data. In general, the monitoring data should be considered a lower bound on
exposure, while modeling represents an upper bound. For malathion, however, the
comparison of predicted aquatic EECs to targeted and non-targeted monitoring data
(Figure 13) indicates the aquatic exposure assessment is not conservative.

6.1.1 Modeling Assumptions

The uncertainties incorporated in the exposure assessment cannot be quantitatively
characterized. However, given the available data and the EFED's policy to rely on
conservative modeling assumptions, it is typically expected that the modeling results in
an over-prediction of exposure. Qualitatively, conservative assumptions which may affect
exposure include the following:

• Modeling for each use site assumes that the entire 10-hectare watershed is taken
up by the respective use pattern. This assumption applies to PRZM/EXAMS
modeling (aquatic phase effects) and is likely a valid assumption for crops that are
grown in large, contiguous tracks or for land uses that cover large, contiguous
areas (e.g., forestry, mosquito control in urban areas, etc.). However, it is likely
invalid for many minor crops that are grown in small plots interspersed with crops
on which pesticides other than malathion are used or to which malathion is
applied at a different time. For uses where this assumption is valid, this
assumption does not result in a conservative assessment (overly protective of the
CRLF). The degree of conservatism in this assumption varies indirectly (varies
inversely) with the likelihood that the assumption is valid (less validity results in
more conservatism).

228


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•	The assessment assumes all applications have occurred concurrently on the same
day at the exact same application rate. This assumption occurs in PRZM/EXAMS
modeling and defining the action area (aquatic phase effects). Again, this is likely
a valid assumption for crops that are grown in large, contiguous tracks and
becomes an increasingly conservative assumption as the application areas become
smaller, less contiguous, and more heterogeneous in terms of uses.

•	The assessment assumes all applications are at the maximum label rate. This
assumption is addressed in the following section (6.1.2).

6.1.2 Application Rate Uncertainty

This risk assessment focuses on maximum malathion application rates because the EPA
approved maximum application rates that appear on malathion labels are the federal
actions that are being evaluated in this assessment. However, pesticides are not
necessarily applied at the maximum application rates that appear on the current labels.
Under those circumstances in which malathion is applied at the maximum rate, the
assumption that malathion is applied at the maximum rate would not be conservative. It is
only when malathion is applied at lower application rate that the assessment becomes
increasingly conservative.

Besides the current labels, there are two additional useful sources of information on
malathion application rates. First, the CDPR PUR data set describes how malathion has
been applied in the recent past (2001 through 2005) in California. From the CDPR PUR
data, average pesticide application rates can be determined for individual crop/sites. The
CDPR PUR averages can serve as a lower boundary estimate of the typical application
rate. Second, the RED (USEPA 2006) describes maximum application rates that were
agreed to be supported by the registrant for malathion, Cheminova, and the USDA's
inter-regional team #4 (IR-4) for future pesticide labeling for approximately 100 food
crop uses. Because this agreement would produce a reduction in intensity of malathion
application (lower application rates) from many of the current labels, this agreement
likely represents an upper-bound of what future labels will allow. USEPA may require
further reductions in malathion application rates than the Cheminova/lK-4 agreement, but
would be unlikely to issue future labels that allow higher application rates.

Table 48 compares the maximum current label rates, maximum Cheminova/TR-4
agreement rate, and average CDPR PUR application rates (averaged annually and across
all years). These 3 information sources (current labels, Cheminova/lK-4 agreement, and
CDPR PUR data) refer to similar uses using dissimilar names. Some professional
judgment was necessary to interpret which specific uses in each of these information
sources were comparable. Other interpretations are possible (and potentially preferable),
but it is assumed that small changes (e.g., interpreting a minor use in one data set as
belonging to a different scenario group) would not lead to substantial changes in this
comparison. (The "total acres" values provided for the CDPR PUR data refers to the sum
of acres treated across all years (2001 - 2005). Care should be taken in interpreting these

229


-------
total acres values. For many crop/sites, the same lands will be treated year after year,
while for other crop/sites, different lands may be treated each year.)

230


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Table 48. Comparison of maximum application rates from current labels to the maximum supported Cheminova and IR-4 application rates and the
average application rates calculated from the 2001-2005 CDPR PUR data for each crop/site grouping (all application rates in lbs ai/A).	

•Maximum Current Label Rates

Chcminova/IR-4 Agreement

CaPUR







Max.



Average Lbs. ai/A

Group

Maximum



Lbs.













All Years

Crop/Site

Lbs. ai/A1

Crop/Site

ai/A

Crop/Site

2001

2002

2003

2004

2005

(Total Acres)

Agricultural Uses

1. Alfalfa, Clover,
Lespedeza, Lupine, Trefoil,
and Vetch

Air: 2
Other: 2

G2(14D) Alfalfa, Clover,
Lespedeza, Lupine and Vetch

1.25

Alfalfa
Clover

1.23
1.53

1.34
N.A.

1.24
N.A.

1.27
3.91

1.18
N.A.

1.26 (477,150)
1.90 (195)

2. Macadamia Nut
(Bushnut)

Air: 15
Other: 15

E7(7D) Macadamia

.94

N.A.

3. Pecan and Walnut
(English/Black)

Air: 12.5
Other: 12.5

L3(7D) Mustards, Walnuts,
and Pecans

2.5

Pecan
Walnut
(English/Black)

N.A.
3.72

.94
3.43

N.A.
3.96

6.22
3.89

9.69
4.22

7.43 (31.1)
3.80 (36,938)

4. Chestnut

Air: 5
Other: 5

P4(7D) Chestnuts

5

N.A.

5. Almond

Air: 1.25
Other: 4

N.A.

Almond

1.60

6.13

1.80

N.A.

N.A.

1.92(187)

6. Date

Air: 1
Other: 2

N.A.

Date

2.81

2.79

2.78

2.48

2.72

2.72 (17,008)

7. Filbert (Hazelnut)

Air: .625
Other: .625

N.A.

N.A.

8. Avocado

Air: 9
Other: 9

O2(30D) Avocado

6.25

Avocado

7.99

.14

.16

.33

3.54

.19 (42,945)

9. Citrus, Citrus Hybrids
other than Tangelo,
Grapefruit, Kumquat,
Lemon, Lime, Orange,
Tangelo, and Tangerines

Air: 25
Other: 25

A10 Orange, Grapefruit,
Lemon, Lime, Tangerine,
Tangelo, and Kumquat

Q3(30D) Oranges, Grapefruit,
Lemon, Lime, Tangerine and
Tangelo

.175
6.25

Citrus

Grapefruit

Kumquat

Lemon

Lime

Orange

Tangelo

Tangerine

1.84
6.93
N.A.
29.61
N.A.
3.18
9.80
16.95

3.17
2.37
N.A.
38.26
N.A.
1.92
9.98
5.37

1.79
.14
.07
1.72
.12
.99

3.61

8.62

1.05
.38
N.A.
23.65
N.A.
1.11
5.18
3.93

I.24
4.47
N.A.
2.30

II.52
2.02
.43
7.10

2.18 (532)
.66 (2200)
.07 (105)
27.69 (1278)

2.20 (22)
1.66 (44,081)
4.85 (295)
7.72 (1673)

231


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Maximum Current Label Rates

Cheminova/IR-4 Agreement

CaPUR







Max.



Average Lbs. ai/A

Group

Maximum



Lbs.













All Years

Crop/Site

Lbs. ai/A1

Crop/Site

ai/A

Crop/Site

2001

2002

2003

2004

2005

(Total Acres)









Bok Choy

1.64

1.91

1.94

2.01

1.69

1.83 (1966)









Broccoli

1.86

1.72

2.03

1.96

1.99

1.94 (16,735)

10. Amaranth - Chinese,
Broccoli (Unspecified,
Chinese, and Raab),

Cabbage (Unspecified and
Chinese), Canola\Rape,
Cauliflower, Collards, Corn
Salad, Dock (Sorrel),
Horseradish, Kale, Kohlrabi,
Mustard, Mustard Cabbage
(Gai Choy/Pak-Choi), and
Purslane (Garden and
Winter)

Air: 2.5
Other: 2.5

G2(7D) Brussel sprouts,
cauliflower, collards, kale,
kohlrabi

G5(7D) Turnip, Broccoli,
Apple, Sweet Corn, Beet,
Horseradish, Parsnip, Radish,
Rutabaga, and Salsify

G6(7D) Cabbage and Cherry
(ULV)

L3(7D) Mustards, Walnuts,
and Pecans

1.25
1.25

1.25
2.5

Cabbage
Canola (Rape)
Cauliflower
Chinese Cabbage

(Nappa)

Chinese Greens
Collard
Gai Choy
Gai Lon
Kale
Kohlrabi
Mizuna
Mustard

Rappini (Broccoli

Rabe)

Vegetable
Leafy Vegetables

1.72
1.92
1.86
1.92

.70

1.58
N.A.
1.85

1.91
1.40
N.A.

1.59

1.92

1.96
1.92

1.62

1.92
1.91
2.15

1.02
2.48
N.A.
1.89
1.96

1.03
N.A.

1.93
N.A.

N.A.
N.A.

1.61
2.10
1.73
1.94

1.86
2.82
N.A.
2.05
2.00
1.02
N.A.
2.53
N.A.

2.00
N.A.

1.82
2.40

1.83
1.93

2.23
2.50
1.20
1.85
2.05
1.11
2.16
1.57
2.13

N.A.
N.A.

2.02
1.78
2.17
1.88

2.20

1.72

.60

1.65

2.04

1.02

N.A.

2.40

2.01

N.A.
N.A.

1.83 (3529)
2.10(1227)
1.98 (1824)

1.98	(8571)

1.32 (376)
2.47 (205)
1.08 (5.1)
1.89 (1232)

1.99	(2484)
1.14(42.5)
2.16(40)
2.07 (683)
2.05 (86.6)

1.98(11.2)
1.92 (20)

11. Corn (Unspecified,
Field, Pop, and Sweet), and
Millet (Foxtail)

Air: 1.5
Other: 1.5

G2(3D) Field corn

G3(7D) Rice, Sorghum,
Wheat, Rye, Barley, Oats, and
Corn

1.25
1.25

Corn (Forage -

Fodder)

Corn, Human
Consumption

1.13
.68

1.10
.84

.97
.84

.86
.89

.89
1.04

1.01 (1820)
.83 (7797)

12. Cotton

Air: 4
Other: 4

L25(3D) Cotton

2.5

Cotton

.55

.77

1.90

1.24

1.27

1.03 (19,616)

15. Apricot

Air: 10
Other: 10

N4(7D) Apricots

3.75

Apricot

N.A.

4.09

4.09

N.A.

2.73

3.41 (6)

16. Nectarine and Peach

Air: 9
Other: 9

N4(14D) Peach and Nectarine

3.75

Nectarine
Peach

7.68
5.64

3.27
1.18

4.93
1.93

7.47
3.84

5.88
4.09

5.04 (72.4)
3.43 (91.2)

17. Cherry

Air: 8
Other: 8

N6(7D) Cherry

3.75

Cherry

2.85

.51

6.45

4.13

6.40

6.19 (432)

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Maximum Current Label Rates

Cheminova/IR-4 Agreement

CaPUR







Max.



Average Lbs. ai/A

Group
Crop/Site

Maximum
Lbs. ai/A1

Crop/Site

Lbs.
ai/A

Crop/Site

2001

2002

2003

2004

2005

All Years
(Total Acres)

18. Fig

Air: 2.5
Other: 2.5

L3(5D) Figs

2.5

Fig

2.47

1.53

2.06

2.41

N.A.

2.35 (1895)





G10(7D) Pears and Quince

1.25















19. Apple, Pear, and Quince

Air: 1.25
Other: 1.5

G5(7D) Turnip, Broccoli,
Apple, Sweet Corn, Beet,
Horseradish, Parsnip, Radish,
Rutabaga, and Salsify

1.25

Apple

Pear

Quince

1.98
19.69
N.A.

.22
16.35
N.A.

.84
N.A.
.75

1.08
3.89
N.A.

.73
3.75
N.A.

1.19(95.3)
4.8 (107.4)
.75 (16)

20. Guava, Mango, Plum,
and Prune

Air: .75
Other: 1.5

G12(7D) Guava and Papaya

G8(7D) Mango and Passion
fruit

1.25
1.25

Mango

Plum

Prune

Tropical/Subtropical
Fruit

N.A.
37.01
.39
N.A.

N.A.
1.58
.05
N.A.

.27
N.A.
N.A.
.11

N.A.
N.A.
N.A.
2.47

N.A.
.30
N.A.
N.A.

.27 (30)
.5 (21.5)
.28 (89)
1.79 (21)

21. Papaya

Air: .175
Other: .175

G12(7D) Guava and Papaya

1.25

N.A.

22. Garlic and Leek

Air: 2
Other: 2

I5(7D) Onion, Garlic, Shallot,
and Leeks

1.56

Garlic
Leek

1.92
1.92

1.57
1.92

1.11
1.75

1.93
1.72

1.82
1.60

1.87 (5329)
1.8(152.7)

23. Grapes

Air: 2.75
Other: 27.47

J2(14D) Grapes

1.88

Grape

Wine Grape

1.25
1.57

1.33
1.56

1.62
2.08

2.62
1.73

1.53
1.90

1.55 (4858)
1.67 (10,136)

26. Brussel Sprouts and .
Dandelion

Air: 2.5
Other: 2.5

G2(7D) Brussel sprouts,
cauliflower, collards, kale,
and kohlrabi

1.25

Brussel Sprout

.68

1.41

1.51

1.20

2.29

1.17(78.8)

27. Swiss Chard, Chervil,
Endive (Escarole), Lettuce,
Head Lettuce, Leaf Lettuce
(Black Seeded Simpson,
Salad Bowl, Etc.), Orach
(Mountain Spinach),
Parsley, Roquette
(Arrugula), Salsify, and
Spinach

Air: 2
Other: 2

G5(7D) Turnip, Broccoli,
Apple, Sweet Corn, Beet,
Horseradish, Parsnip, Radish,
Rutabaga, and Salsify

J6(5D) Lettuce

K3(7D) Spinach, Dandelion,
Endive, Parsley, and Swiss
Chard

1.25

1.88
2.03

Arrugula
Endive (Escarole)
Lettuce, Head
Lettuce, Leaf
Parsley
Spinach
Swiss Chard

N.A.
1.62
1.78
1.38
1.50
1.58
1.70

1.28
1.52
1.45
1.41
1.02
1.50
1.86

N.A.
1.39
1.54
1.52
2.45
1.48
1.38

1.93
1.39
1.61
1.55
1.42
1.55
1.86

2.04
1.37
1.66
1.68
1.28
1.44
1.47

1.88 (69.1)
1.51 (1670)
1.61 (103,880)
1.48 (57,737)
1.5 (46.9)
1.49 (4228)
1.71 (408.6)

233


-------
Maximum Current Label Rates

Cheminova/IR-4 Agreement

CaPUR







Max.



Average Lbs. ai/A

Group

Maximum



Lbs.













All Years

Crop/Site

Lbs. ai/A1

Crop/Site

ai/A

Crop/Site

2001

2002

2003

2004

2005

(Total Acres)

28. Peppermint

Air: 1
Other: 1

E3(7D) Peppermint and
spearmint

.94

Pepper, Spice

.96

1.02

N.A.

1.45

N.A.

1.24 (71.5)

29. Eggplant

Air: 3.5
Other: 3.5

M5(5D) Tomato, Pepper, and
Eggplant

3.43

Eggplant

1.16

.94

.77

1.56

2.08

1.55 (110.4)

30. Pumpkin

Air: 2
Other: 2

F6(7D) Melons, Watermelon,
Pumpkin, and Winter Squash

1.0

Cantaloupe

Cucumber

Pumpkin

1.23
1.50
1.46

1.14
1.83
1.64

1.20
1.72
.49

1.73
1.65
1.46

1.22
1.88
1.20

1.27 (955)
1.63 (1216)
1.37 (3926)

31. Cucumber, Cucurbit





















Vegetables, Melons -
Unspecified, Cantaloupe,
Honeydew, Musk, Water,
and Winter

Air: 1.875
Other: 1.875

F6(7D) Melons, Watermelon,
Pumpkin, and Winter Squash

J3(7D) Cucumber and
Chayote

1.0
1.88

Melon
Squash

Squash, Summer
Squash, Winter

6.32
1.58
1.57
1.45

2.41
1.63
1.65
.19

1.77
1.39
1.49
N.A.

3.72
1.58
1.65
2.45

2.04
1.31
1.64
1.54

2.54 (33.6)
1.52 (1436)
1.61 (1311)
.84 (17.7)

(Casaba/Crenshaw/Honeyde
w/Persian), and Squash (All
Or Unspecified)



Squash, Zucchini
Watermelon

1.38
1.44

N.A.
1.60

N.A.
1.43

N.A.
1.48

1.50
1.53

1.4 (110)
1.48 (454.9)

32. Onion (Unspecified and
Green), Radish, and Shallot

Air: 2
Other: 2

G5(7D) Turnip, Broccoli,
Apple, Sweet Corn, Beet,
Horseradish, Parsnip, Radish,
Rutabaga, and Salsify

1.25

Chive
Daikon
Onion, Dry
Onion, Green

N.A.
.59
1.19
1.77

N.A.
N.A.
1.30
1.98

N.A.
N.A.
1.74
1.70

1.18
N.A.
1.47
1.97

1.02
N.A.
1.54
2.16

1.16 (11)
.59 (1.25)
1.49 (15,907)
1.89 (5440)





I5(7D) Onion, Garlic, Shallot,
and Leeks

1.56

Radish
Shallot

1.52
N.A.

1.72
N.A.

1.79
N.A.

1.41
N.A.

1.92
2.04

1.79 (301.4)
2.04 (65.9)

33. Potato - White/Irish

Air: 3
Other: 3

I2(7D) Potato and Sweet
potato

1.56

Potato

1.25

.98

1.88

2.04

N.A.

1.7 (771)

34. Turnip

Air: 2.5
Other: 2.5

G5(7D) Turnip, Broccoli,
Apple, Sweet Corn, Beet,
Horseradish, Parsnip, Radish,
Rutabaga, and Salsify

1.25

Turnip

2.04

2.01

2.24

1.48

1.61

1.97 (420.8)

35. Parsnip and Rutabaga

Air: 2
Other: 2

G5(7D) Turnip, Broccoli,
Apple, Sweet Corn, Beet,
Horseradish, Parsnip, Radish,
Rutabaga, and Salsify

1.25

Parsnip

N.A.

N.A.

1.94

N.A.

N.A.

1.94 (32.32)

234


-------
Maximum Current Label Rates

Cheminova/IR-4 Agreement

CaPUR







Max.



Average Lbs. ai/A

Group
Crop/Site

Maximum
Lbs. ai/A1

Crop/Site

Lbs.
ai/A

Crop/Site

2001

2002

2003

2004

2005

All Years
(Total Acres)

36. Sweet Potato

Air: 1.875
Other: 1.875

I2(7D) Potato and Sweet
potato

1.56

Sweet Potato

1.62

9.45

1.54

2.15

1.22

2.15 (288)

37. Bluegrass, Canarygrass,
Grass Forage/Fodder/Hay,
Pastures, Peas (Including
Vines), Rangeland,
Sudangrass, and Timothy

Air: 1.25
Other: 1.25

G1(3D) Grass for hay

1.25

Forage Hay/Silage
Grass, Seed
Pastureland
Rangeland
Sudangrass

1.39
N.A.
.79
.66
N.A.

1.32
N.A.
1.00
N.A.
N.A.

1.25
1.19
1.25
1.41
1.19

1.23
N.A.

1.24
N.A.
N.A.

1.20
N.A.
1.33
.98
N.A.

1.31 (10,938)
1.19(58)
1.19 (733)
.72 (318)
1.19 (90)

40. Beets,

Cowpea/Blackeyed Pea, and
Peas (Unspecified and
Field)

Air: 2.5
Other: 2.5

G5(7D) Beans, Corn, Rice,
Sorghum, Wheat, and Rye

L5(7D) Peas

1.25
2.5

Beet
Peas

2.16
.55

2.68
.57

1.78
.97

2.03
1.32

1.53
.69

2.22 (441.4)
.85 (8670)





G7(7D) Carrot

1.25















41. Carrot (Including Tops),
Celtuce, Fennel, and Pepper

Air: 2
Other: 2

K3(7D) Spinach, Dandelion,
Endive, Parsley, and Swiss
Chard

M5(5D) Tomato, Pepper, and
Eggplant

2.03
3.43

Carrot
Fennel

Fruiting Pepper

1.80
2.04
.99

1.05
N.A.
1.16

1.71
N.A.
1.39

2.00
1.52
1.49

1.67
2.05
1.28

1.78 (5521)
1.81 (86)
1.25 (3637)

42. Beans, Beans - Dried-
Type, Beans - Succulent
(Lima), and Beans -
Succulent (Snap)

Air: 1.75
Other: 1.75

C3(7D) Beans, Corn, Rice,
Sorghum, Wheat, and Rye

.61

Dried Bean
Succulent Bean
Unspecified Bean

1.46
1.07
1.38

.88
1.28
1.46

1.35
1.26
1.40

1.21
1.31
1.50

1.56
1.52
1.46

1.17 (12,043)
1.23 (5378)
1.42 (1247)

43. Celery

Air: 1.5
Other: 1.5

H2(7D) Celery

1.5

Celery

1.42

1.41

1.41

1.46

1.50

1.44 (57,200)

44. Asparagus and
Safflower (Unspecified)

Air: 1.25
Other: 1.25

G9(7D) Asparagus

1.25

Asparagus
Safflower

1.12
1.20

1.36
N.A.

1.23
N.A.

1.22
N.A.

1.28
N.A.

1.19 (1052)
1.2 (140)

45. Anise

Air: .9375
Other: .9375

G7(7D) Carrot

1.25

N.A.

46. Strawberry

Air: 2
Other: 2

E6(6D) Strawberry
K6(6D) Strawberry

.94
2.03

Strawberry

1.87

1.84

1.85

1.98

2.08

1.92 (211,559)

235


-------
Maximum Current Label Rates

Cheminova/IR-4 Agreement

CaPUR







Max.



Average Lbs. ai/A

Group
Crop/Site

Maximum
Lbs. ai/A1

Crop/Site

Lbs.
ai/A

Crop/Site

2001

2002

2003

2004

2005

All Years
(Total Acres)

47. Sugar Beet

Air: 1.875
Other: 1.875

G5(7D) Turnip, Broccoli,
Apple, Sweet Corn, Beet,
Horseradish, Parsnip, Radish,
Rutabaga, and Salsify

1.25

Sugarbeet (CDPR
PUR data appears to
be erroneous)

0

N.A.

N.A.

N.A.

N.A.

0 (775)

48. Tomato

Air: 3.5
Other: 3.5

M5(5D) Tomato, Pepper, and
Eggplant

3.43

Tomatillo
Tomato

Processing Tomato

.61

1.56

1.15

.64
1.28
1.11

.58
.32
1.10

.90
.91
1.22

N.A.
1.70
1.40

.67 (142)
.78 (3765)
1.12(18,094)

49. Okra

Air: 1.5
Other: 1.5

H6(7D) Okra

1.5

Okra

N.A.

N.A.

N.A.

N.A.

1.40

1.4 (140)

51. Sorghum

Air: 1.5
Other: 1.5

G3(7D) Rice, Sorghum,
Wheat, Rye, Barley, Oats, and
Corn

1.25

Sorghum (Forage -

Fodder)
Sorghum/Milo

N.A.
N.A.

.03
N.A.

N.A.
N.A.

N.A.
1.53

1.47
N.A.

1.28 (188)
1.53 (30.2)

52. Barley, Cereal Grains,
Oats, Rye, and Wheat

Air: 1.25
Other: 1.25

G3(7D) Rice, Sorghum,
Wheat, Rye, Barley, Oats, and
Corn

1.25

Barley
Oat

Oat (Forage -

Fodder)

Wheat

Wheat (Forage -
Fodder)

1.09
1.27
1.21

1.03
N.A.

1.04
.87
1.19

1.02
1.25

1.07
.99
1.44

.98
1.00

1.14
1.21
.75

1.03
.96

1.07
1.13
1.20

.99
.97

1.07	(5316)

1.08	(1082)
1.11 (486.9)

1.01 (18,978)
1.05 (1303)

53. Gooseberry

Air: 16
Other: 16

K4(7D) Blackberry,
Raspberry, Gooseberry,
Loganberry, Dewberry,
Currant, and Boysenberry

2.03

N.A.

54. Blackberry,
Boysenberry, Dewberry,
Loganberry, and Raspberry
(Black - Red)

Air: 4
Other: 4

K4(7D) Blackberry,
Raspberry, Gooseberry,
Loganberry, Dewberry,
Currant, and Boysenberry

2.03

Blackberry
Raspberry

3.38
1.23

3.33
1.29

2.78
1.45

3.45
1.81

3.44
1.29

3.26 (2297)
1.42 (8172)

55. Blueberry

Air: 2.5
Other: 2.5

G4(7D) Blueberry

1.25

Blueberry

1.47

1.92

2.18

1.00

N.A.

2.16 (325.1)

56. Caneberries and Currant

Air: 2
Other: 2

K4(7D) Blackberry,
Raspberry, Gooseberry,
Loganberry, Dewberry,
Currant, and Boysenberry

2.03

N.A.

236


-------
Maximum Current Label Rates

Cheminova/IR-4 Agreement

CaPUR







Max.



Average Lbs. ai/A

Group

Maximum



Lbs.













All Years

Crop/Site

Lbs. ai/A1

Crop/Site

ai/A

Crop/Site

2001

2002

2003

2004

2005

(Total Acres)

57. Passion Fruit
(Granadilla)

Air: .75
Other: .75

G8(7D) Mango and Passion
fruit

1.25

N.A.

58. Mint and Spearmint

Air: 1
Other: 1

E3(7D) Peppermint and
spearmint

.94

Mint

.87

.88

.99

.94

.90

.95 (1116)

59. Rice and Wild Rice

Air: 1.5625

Other:

1.5625

G3(7D) Rice, Sorghum,
Wheat, Rye, Barley, Oats, and
Corn

1.25

Rice

Wild Rice

1.16
1.76

1.23
1.48

1.52
1.48

N.A.
1.09

1.49
1.45

1.31 (1772)
1.45 (3083)

61. Water Cress

Air: 2
Other: 2

G5(5D) Watercress

1.25

Watercress

1.08

.97

1.17

1.09

.95

1.07 (1628)





Non-

agricultural Uses













Forestry. Christmas Tree





















Plantations, Pine (Seed
Orchard), and Slash Pine

Air: 3.2
Other: 3.2

Commercial Tree Production

N.A.

Christmas Tree

N.A.

N.A.

2.94

7.47

2.08

3.48 (223)

(Forest)





















Mosquito Control.

Intermittently Flooded
Areas/Water,





















Lakes/Ponds/Reservoirs





















(with Human or Wildlife

Use),

Lakes/Ponds/Reservoirs

Air: .6
Other: .6

Mosquito Control

N.A.





N.A.







(without Human or Wildlife





















Use), Polluted Water, and





















Swamps/MarshesAV etlands/
Stagnant Water





























N-Outdoor Flower

1.74

1.13

.63

.75

1.12

1.09(1311)

Nursery. Outdoor Nursery

Air: 2.252
Other: 2.252

Ornamental Plant Uses-
Nurseries-Homeowner

N.A.

N-Outdoor Plants In

Containers
N-Outdoor
Transplants

.99
2.77

.53
1.87

1.71
1.81

1.88
1.50

1.75
1.72

1.16(23,446)
2.23 (1471)

237


-------
Maximum Current Label Rates

Cheminova/IR-4 Agreement

CaPUR

1 1 Max.

Average Lbs. ai/A

Group
Crop/Site

Maximum
Lbs. ai/A1

Crop/Site

Lbs.
ai/A

Crop/Site

2001

2002

2003

2004

2005

All Years
(Total Acres)

Public Health and Medfly
Control. Nonagricultural
Areas (Public Health Use),
Urban Areas, and Wide
Area/General Outdoor
Treatment (Public Health
Use)

Air: .6119
Other: .1361

Public Health

N.A.

Buildings/Non-Ag
Outdoor

Not reported on a lbs. ai/A basis.

Residential.

Household/Domestic
Dwellings Outdoor
Premises, Ornamental
and/or Shade Trees,
Ornamental Herbaceous
Plants, Ornamental Lawns
and Turf, Ornamental Non-
flowering Plants,
Ornamental Woody Shrubs
and Vines, and Urban Areas

Other: ,253

Homeowner Use

N.A.

Landscape
Maintenance

N.A.

N.A.

1.28

2.47

.78

1.29 (7.5)

Rights-of-way.

Nonagricultural Rights-of-
way/Fencerows/Hedgerows
and Nonagricultural
Uncultivated Areas/Soils

Air: .9281
Other: .9281

Nonagricultural rights of
way/fencerows/hedgerows

N.A.

Rights Of Way
Uncultivated Ag
Uncultivated Non-Ag

N.A.
.24
1.81

N.A.
N.A.
2.38

N.A.
N.A.
N.A.

1.24
.59
N.A.

N.A.
1.18
N.A.

1.24 (.62)
.6 (102.5)
1.94(131)

Turf. Golf Course Turf

Air: 1.25
Other: 1.25

Turf Use/Golf Courses/
Commercial Lawn care

N.A.

Bermudagrass

1.06

1.05

1.18

1.32

1.07

1.13 (19,770)

1	"Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

2	Based on CDPR PUR (Nursery Outdoor transplants) data average for 2001 through 2005 (rounded from 2.23 lbs./A).

3	Assumes 0.1 acres of a ten acre watershed treated at 25 lbs ai/A (citrus) on 10 consecutive weekends (does not assume the same parcels are re-treated each
weekend): 25 lbs. ai/A x 0.1acres/10 acre watershed = 0.25 lbs. ai/A.

238


-------
Table 48 shows that many application rates would be reduced if the maximum
application rates proposed under the Cheminova/lK-4 agreement were implemented.
Similarly, the average CDPR PUR average application rates are much lower than the
current maximum label application rates.

To help determine if the risk to the CRLF might be solely due to the conservative
assumption that malathion is applied at maximum application rates, Table 49 compares
the malathion RQs for acute aquatic invertebrates to estimated RQs for the proposed
Cheminova/TR-4 agreement application rates. The estimated Cheminova/lR-4 RQs
([RQsstimate) assume RQs are linear function of application rate:

Rn = Rn APPRate Estate

Estimate	Model

AppRate

Model

Where: RQModei is the RQ derived from the maximum label application rate for a use,
AppRate Estimate is the proposed Cheminova/lK-4 agreement, and AppRateModei is the
maximum label application rate for a use. Although many of the processes modeled by
EFED models are nonlinear, the assumption of a linear relationship between application
rate and RQ is sufficiently accurate to indicate whether the risks identified in Section 5
are potentially due primarily from assuming malathion is applied at the maximum label
rates.

Table 49. Chronic invertebrate risk quotients (RQs) estimated for CheminovalIR-4 supported
maximum malathion application rates (agricultural uses only) listed by current label crop/site.

Current Label

Cheminova/IR-4 Agreement

Crop/Site

Crop/Site

RQ (Estimated)

1. Alfalfa, Clover, Lespedeza, Lupine,
Trefoil, and Vetch

G2(14D) Alfalfa, Clover, Lespedeza,
Lupine and Vetch

Air1: 88,017#
Other: 36,918#

2. Macadamia Nut (Bushnut)

E7(7D) Macadamia

Air: 56,499#
Other: 13,214#

3. Pecan and Walnut (English/Black)

L3(7D) Mustards, Walnuts, and
Pecans

Air: 134,662#
Other: 27,444#

4. Chestnut

P4(7D) Chestnuts

Air: 281,854#
Other: 57,323#

5. Almond

N.A.

6. Date

N.A.

7. Filbert (Hazelnut)

N.A.

8. Avocado

O2(30D) Avocado

Air: 247,284#
Other: 49,460#

9. Citrus, Citrus Hybrids other than
Tangelo, Grapefruit, Kumquat, Lemon,
Lime, Orange, Tangelo, and Tangerines

A10 Orange, Grapefruit, Lemon,

Lime, Tangerine, Tangelo, and
Kumquat

Q3(30D) Oranges, Grapefruit, Lemon,
Lime, Tangerine and Tangelo

Air: 12,196#
Other: 2,462#

Air: 435,577#
Other: 87,913#

239


-------
Current Label

Cheminova/IR-4 Aj>

rccmcnt

Crop/Site

Crop/Site

RQ (Estimated)

10. Amaranth - Chinese, Broccoli
(Unspecified, Chinese, and Raab),
Cabbage (Unspecified and Chinese),
Canola\Rape, Cauliflower, Collards,
Corn Salad, Dock (Sorrel),
Horseradish, Kale, Kohlrabi, Mustard,
Mustard Cabbage (Gai Choy/Pak-
Choi), and Purslane (Garden and
Winter)

G2(7D) Brussel sprouts, cauliflower,
collards, kale, kohlrabi

G5(7D) Turnip, Broccoli, Apple,
Sweet Corn, Beet, Horseradish,
Parsnip, Radish, Rutabaga, and Salsify

G6(7D) Cabbage and Cherry (ULV)

L3(7D) Mustards, Walnuts, and
Pecans

Air: 87,221#
Other: 17,446#

Air: 87,221#
Other: 17,446#

Air: 87,221#
Other: 17,446#
Air: 174,442#
Other: 34,892#

11. Corn (Unspecified, Field, Pop, and
Sweet), and Millet (Foxtail)

G2(3D) Field corn

G3(7D) Rice, Sorghum, Wheat, Rye,
Barley, Oats, and Corn

Air: 68,378#
Other: 13,679#
Air: 68,378#
Other: 13,679#

12. Cotton

L25(3D) Cotton

Air: 304,784#
Other: 60,933#

15. Apricot

N4(7D) Apricots

Air: 235,240#
Other: 47,061#

16. Nectarine and Peach

N4(14D) Peach and Nectarine

Air: 211,939#
Other: 42,401#

17. Cherry

N6(7D) Cherry

Air: 261,653#
Other: 52,358#

18. Fig

L3(5D) Figs

Air: 112,254#
Other: 22,447#

19. Apple, Pear, and Quince

G10(7D) Pears and Quince

G5(7D) Turnip, Broccoli, Apple,
Sweet Corn, Beet, Horseradish,
Parsnip, Radish, Rutabaga, and Salsify

Air: 73,642#
Other: 14,726#
Air: 73,642#
Other: 14,726#

20. Guava, Mango, Plum, and Prune

G12(7D) Guava and Papaya
G8(7D) Mango and Passion fruit

Air: 98,449#
Other: 9,845#
Air: 98,449#
Other: 9,845#

21. Papaya

G12(7D) Guava and Papaya

Air: 98,467#
Other: 19,691#

22. Garlic and Leek

I5(7D) Onion, Garlic, Shallot, and
Leeks

Air: 108,810#
Other: 41,043#

23. Grapes

J2(14D) Grapes

Air: 65,135#
Other: 13,026#

26. Brussel Sprouts and . Dandelion

G2(7D) Brussel sprouts, cauliflower,
collards, kale, and kohlrabi

Air: 83,992#
Other: 17,073#

27. Swiss Chard, Chervil, Endive
(Escarole), Lettuce, Head Lettuce, Leaf
Lettuce (Black Seeded Simpson, Salad
Bowl, Etc.), Orach (Mountain Spinach),
Parsley, Roquette (Arrugula), Salsify,
and Spinach

G5(7D) Turnip, Broccoli, Apple,
Sweet Corn, Beet, Horseradish,
Parsnip, Radish, Rutabaga, and Salsify

J6(5D) Lettuce

K3(7D) Spinach, Dandelion, Endive,
Parsley, and Swiss Chard

Air: 162,406#
Other: 79,469#

Air: 244,259#
Other: 119,521#
Air: 263,748#
Other: 129,057#

28. Peppermint

E3(7D) Peppermint and spearmint

Air: 63,533#
Other: 12,972#

240


-------
Current Label

Cheminova/IR-4 Aj>

rccmcnt

Crop/Site

Crop/Site

RQ (Estimated)

29. Eggplant

M5(5D) Tomato, Pepper, and
Eggplant

Air: 223,289#
Other: 45,084#

30. Pumpkin

F6(7D) Melons, Watermelon,
Pumpkin, and Winter Squash

Air: 62,498#
Other: 12,501#

31. Cucumber, Cucurbit Vegetables,
Melons - Unspecified, Cantaloupe,
Honey dew, Musk, Water, and Winter
(Casaba/Crenshaw/Honeydew/Persian),
and Squash (All Or Unspecified)

F6(7D) Melons, Watermelon,
Pumpkin, and Winter Squash

J3(7D) Cucumber and Chayote

Air: 64,841#
Other: 13,600#

Air: 121,901#
Other: 25,568#

32. Onion (Unspecified and Green),
Radish, and Shallot

G5(7D) Turnip, Broccoli, Apple,
Sweet Corn, Beet, Horseradish,
Parsnip, Radish, Rutabaga, and Salsify

I5(7D) Onion, Garlic, Shallot, and
Leeks

Air: 96,925#
Other: 26,007#

Air: 120,963#
Other: 32,457#

33. Potato - White/Irish

I2(7D) Potato and Sweet potato

Air: 81,926#
Other: 16,387#

34. Turnip

G5(7D) Turnip, Broccoli, Apple,
Sweet Corn, Beet, Horseradish,
Parsnip, Radish, Rutabaga, and Salsify

Air: 76,058#
Other: 15,213#

35. Parsnip and Rutabaga

G5(7D) Turnip, Broccoli, Apple,
Sweet Corn, Beet, Horseradish,
Parsnip, Radish, Rutabaga, and Salsify

Air: 54,474#
Other: 10,897#

36. Sweet Potato

I2(7D) Potato and Sweet potato

Air: 55,293#
Other: 11,467#

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland,
Sudangrass, and Timothy

G1(3D) Grass for hay

Air: 83,827#
Other: 17,320#

40. Beets, Cowpea/Blackeyed Pea, and
Peas (Unspecified and Field)

G5(7D) Beans, Corn, Rice, Sorghum,
Wheat, and Rye

L5(7D) Peas

Air: 87,158#
Other: 17,431#

Air: 174,315#
Other: 34,863#

41. Carrot (Including Tops), Celtuce,
Fennel, and Pepper

G7(7D) Carrot

K3(7D) Spinach, Dandelion, Endive,
Parsley, and Swiss Chard

M5(5D) Tomato, Pepper, and
Eggplant

Air: 121,077#
Other: 24,207#
Air: 196,629#
Other: 39,312#

Air: 332,235#
Other: 66,423#

42. Beans, Beans - Dried-Type, Beans -
Succulent (Lima), and Beans -
Succulent (Snap)

C3(7D) Beans, Corn, Rice, Sorghum,
Wheat, and Rye

Air: 39,793#
Other: 7,959#

43. Celery

H2(7D) Celery

Air: 109,042#
Other: 55,730#

44. Asparagus and Safflower
(Unspecified)

G9(7D) Asparagus

Air: 162,981#
Other: 83,231#

45. Anise

G7(7D) Carrot

Air: 86,656#
Other: 17,335#

241


-------
Current Label

Cheminova/IR-4 Aj>

rccmcnt

Crop/Site

Crop/Site

RQ (Estimated)

46. Strawberry

E6(6D) Strawberry
K6(6D) Strawberry

Air:
Other:
Air:
Other:

83,132#
16,626#
179,530#
35,906#

47. Sugar Beet

G5(7D) Turnip, Broccoli, Apple,
Sweet Corn, Beet, Horseradish,
Parsnip, Radish, Rutabaga, and Salsify

Air:
Other:

100,469#
33,146#

48. Tomato

M5(5D) Tomato, Pepper, and
Eggplant

Air:
Other:

215,721#
43,131#

49. Okra

H6(7D) Okra

Air:
Other:

94,900#
19,043#

51. Sorghum

G3(7D) Rice, Sorghum, Wheat, Rye,
Barley, Oats, and Corn

Air:
Other:

55,343#
11,069#

52. Barley, Cereal Grains, Oats, Rye,
and Wheat

G3(7D) Rice, Sorghum, Wheat, Rye,
Barley, Oats, and Corn

Air:
Other:

170,862#
110,385#

53. Gooseberry

K4(7D) Blackberry, Raspberry,
Gooseberry, Loganberry, Dewberry,
Currant, and Boysenberry

Air:
Other:

156,242#
31,253#

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and Raspberry
(Black - Red)

K4(7D) Blackberry, Raspberry,
Gooseberry, Loganberry, Dewberry,
Currant, and Boysenberry

Air:
Other:

156,259#
31,248#

55. Blueberry

G4(7D) Blueberry

Air:
Other:

108,077#
21,650#

56. Caneberries and Currant

K4(7D) Blackberry, Raspberry,
Gooseberry, Loganberry, Dewberry,
Currant, and Boysenberry

Air:
Other:

156,259#
31,252#

57. Passion Fruit (Granadilla)

G8(7D) Mango and Passion fruit

Air:
Other:

107,077#
21,428#

58. Mint and Spearmint

E3(7D) Peppermint and spearmint

Air:
Other:

54,831#
10,966#

59. Rice and Wild Rice

G3(7D) Rice, Sorghum, Wheat, Rye,
Barley, Oats, and Corn

Air:
Other:

9,640,659#

61. Water Cress

G5(5D) Watercress

Air:
Other:

9,640,659#

1 "Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift
when estimating environmental concentrations. "Other" refers other application methods for which EFED
policy assumes 1% spray drift.

# Chronic RQ >1.0 for listed and unlisted species.

All of the Cheminova/lK-4 supported maximum malathion application rates produce
chronic invertebrate RQs that exceed the LOC of 1 by factors ranging from 2462 to
9,640,659. Therefore, exceedances of the LOC for chronic invertebrate are likely to occur
even if the Cheminova/lK-4 supported maximum malathion application rates were
accepted as the maximum malathion application rates in future malathion labels.

Similar to Table 49, Table 50 presents estimates of the RQs based on the average CDPR
PUR application rates. Also similar, all of the average CDPR PUR application rates
produce chronic invertebrate RQs that exceed the LOC of 1 by factors ranging from 266
to 13,574,048. Therefore, it appears that the risks identified in this assessment are not
solely attributable to the conservatism introduced through modeling based on current
label maximum application rates

242


-------
Table 50. Chronic invertebrate risk quotients (RQs) estimated for the average malathion application rates calculated from the 2001-2005 CDPR PUR
data for each CDPR PUR crop/site grouping listed by current label crop/site.	

Maximum Current Label Rates

CaPUR

Group



RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years

Agricultural Uses



Alfalfa

Air:

86,609#

94,354#

87,313#

89,425#

83,088#

88,721#

1. Alfalfa, Clover, Lespedeza,

Other:

36,328#

39,576#

36,623#

37,509#

34,851#

37,214#

Lupine, Trefoil, and Vetch

Clover

Air:
Other:

107,733#
45,188#

N.A.

N.A.

275,317#
115,480#

N.A.

133,786#
561,16#

2. Macadamia Nut (Bushnut)

N.A.



Pecan

Air:

N.A.

50,633#

N.A.

335,038#

521948#

400214#

3. Pecan and Walnut

Other:

10,319#

68,280#

106372#

81563#

(English/Black)

Walnut (English/Black)

Air:

200,376#

184,756#

213,304#

209,533#

227,309#

204,686#



Other:

40,836#

37,653#

43,471#

42,703#

46,325#

41,715#

4. Chestnut

N.A.

5. Almond

Almond

Air:
Other:

169,822#
76,815#

650,629#
294,299#

191,049#
86,417#

N.A.

N.A.

203,786#
92,178#

6. Date

Date

Air:

101,345#

100,623#

100,263#

89,443#

98,099#

98,099#

Other:

20,364#

20,219#

20,146#

17,972#

19,712#

19,712#

7. Filbert (Hazelnut)

N.A.

8. Avocado

Avocado

Air:

316,127#

5539#

6330#

13,057#

140,061#

7517#

Other:

63,230#

1108#

1266#

2612#

28,014#

1504#

9. Citrus, Citrus Hybrids other than

Citrus

Air:

128,234#

220,925#

124,749#

73,177#

86,418#

151,929#

Tangelo, Grapefruit, Kumquat,

Other:

25,881#

44,589#

25,178#

14,769#

17,442#

30,664#

Lemon, Lime, Orange, Tangelo,

Grapefruit

Air:

482,968#

165,171#

9757#

26,483#

311,525#

45,997#

and Tangerines

Other:

97,477#

33,336#

1969#

5345#

62,875#

9284#



Kumquat

Air:
Other:

N.A.

N.A.

4878#
985#

N.A.

N.A.

4878#
985#



Lemon

Air:

2,063,589#

2,666,428#

119,871#

1,648,223#

160,292#

1,929,780#



Other:

416,494#

538,165#

24,194#

332,661#

32,352#

389,488#



Lime

Air:

N.A.

N.A.

8363#

N.A.

802,855#

153,323#



Other:

1688#

162,040#

30,945#



Orange

Air:

221,622#

133,809#

68,995#

77,358#

140,778#

115,689#



Other:

44,730#

27,007#

13,925#

15,613#

28,413#

23,350#

243


-------
Maximum Current Label Rates

CaPUR

Group



RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years



Tangelo

Air:

682,985#

695,529#

251,589#

361,006#

29,968#

338,008#



Other:

137,847#

140,379#

50,778#

72,862#

6048#

68,220#



Tangerine

Air:

1,181,285#

374,248#

600,748#

273,891#

494,815#

538,025#



Other:

238,419#

75,534#

121,249#

55,279#

99,869#

108,590#

10. Amaranth - Chinese, Broccoli

Bok Choy

Air:

114,434#

133,274#

135,367#

140,252#

117,923#

127,692#

(Unspecified, Chinese, and Raab),

Other:

22,889#

26,658#

27,076#

28,053#

23,587#

25,541#

Cabbage (Unspecified and
Chinese), Canola\Rape,

Broccoli

Air:
Other:

129,785#
25,960#

120,016#
24,006#

141,647#
28,333#

136,763#
27,356#

138,856#
27,774#

135,367#
27,076#

Cauliflower, Collards, Corn Salad,

Cabbage

Air:

120,016#

113,039#

112,341#

126,994#

140,949#

127,692#

Dock (Sorrel), Horseradish, Kale,

Other:

24,006#

22,610#

22,471#

25,402#

28,193#

25,541#

Kohlrabi, Mustard, Mustard
Cabbage (Gai Choy/Pak-Choi),

Canola (Rape)

Air:
Other:

133,972#
26,797#

133,972#
26,797#

146,532#
29,310#

167,465#
33,497#

124,203#
24,843#

146,532#
29,310#

and Purslane (Garden and Winter)

Cauliflower

Air:

129,785#

133,274#

120,714#

127,692#

151,416#

138,158#



Other:

25,960#

26,658#

24,145#

25,541#

30,287#

27,635#



Chinese Cabbage

Air:

133,972#

150,020#

135,367#

134,669#

131,181#

138,158#



(Nappa)

Other:

26,797#

30,007#

27,076#

26,937#

26,239#

27,635#



Chinese Greens

Air:

48,844#

71,172#

129,785#

155,603#

153,509#

92,106#



Other:

9770#

14,236#

25,960#

31,124#

30,705#

18,423#



Collard

Air:

110,248#

173,047#

196,771#

174,442#

120,016#

172,349#



Other:

22,052#

34,613#

39,359#

34,892#

24,006#

34,474#



Gai Choy

Air:
Other:

N.A.

N.A.

N.A.

83,732#
16,748#

41,866#
8374#

75,359#
15,073#



Gai Lon

Air:

129,087#

131,878#

143,043#

129,087#

115,132#

131,878#



Other:

25,820#

26,379#

28,612#

25,820#

23,029#

26,379#



Kale

Air:

133,274#

136,763#

139,554#

143,043#

142,345#

138,856#



Other:

26,658#

27,356#

27,914#

28,612#

28,472#

27,774#



Kohlrabi

Air:

97,688#

71,870#

71,172#

77,452#

71,172#

79,546#



Other:

19,540#

14,376#

14,236#

15,492#

14,236#

15,911#



Mizuna

Air:

N.A.

N.A.

N.A.

150,718#

N.A.

150,718#



Other:

30,147#

30,147#



Mustard

Air:

110,945#

134,669#

176,536#

109,550#

167,465#

144,438#



Other:

22,192#

26,937#

35,311#

21,912#

33,497#

28,891#

244


-------
Maximum Current Label Rates

CaPUR

Group

RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years

Rappini (Broccoli
Rabe)

Air:
Other:

133,972#
26,797#

N.A.

N.A.

148,625#
29,728#

140,252#
28,053#

143,043#
28,612#

Vegetable

Air:
Other:

136,763#
27,356#

N.A.

139,554#
27,914#

N.A.

N.A.

138,158#
27,635#

Leafy Vegetables

Air:
Other:

133,972#
26,797#

N.A.

N.A.

N.A.

N.A.

133,972#
26,797#

11. Corn (Unspecified, Field, Pop,
and Sweet), and Millet (Foxtail)

Corn (Forage - Fodder)

Air:
Other:

61,814#
12,365#

60,173#
12,037#

53,061#
10,615#

47,044#
9411#

48,685#
9739#

55,250#
11,052#

Corn, Human
Consumption

Air:
Other:

37,198#
7441#

45,950#
9192#

45,950#
9192#

48,685#
9739#

56,891#
11381#

45,403#
9083#

12. Cotton

Cotton

Air:
Other:

67,052#
13,405#

93,873#
18,767#

231,636#
46,309#

151,173#
30,223#

154,830#
30,954#

125,571#
25,104#

15. Apricot

Apricot

Air:
Other:

N.A.

256,569#
51,328#

256,569#
51,328#

N.A.

171,255#
34,260#

213,912#
42,794#

16. Nectarine and Peach

Nectarine

Air:
Other:

434,051#
86,837#

184,811#

36,973#

278,629#
55,743#

422,183#
84,462#

332,321#
66,484#

284,846#
56,986#

Peach

Air:
Other:

318,756#
63,771#

66,690#
13,342#

109,078#
21,822#

217,026#
43,418#

231,155#
46,245#

193,854#
38,782#

17. Cherry

Cherry

Air:
Other:

198,856#
39,792#

35,585#
7121#

450,043#
90,055#

288,167#
57,663#

446,554#
89,357#

431,901#
86,425#

18. Fig

Fig

Air:
Other:

110,907#
22,178#

68,699#
13,738#

92,497#
18,497#

108,213#
21,639#

N.A.

105,519#
21,100#

19. Apple, Pear, and Quince

Apple

Air:
Other:

116,649#
23,326#

12,961#
2592#

49,488#
9896#

63,627#
12,723#

43,007#
8600#

70,107#
14,019#

Pear

Air:
Other:

1,160,014#
231,963#

963,241#
192,616#

N.A.

229,175#
45,827#

220,927#
44,178#

282,786#
56,548#

Quince

Air:
Other:

N.A.

N.A.

44,185#
8836#

N.A.

N.A.

44,185#
8836#

20. Guava, Mango, Plum, and
Prune

Mango

Air:
Other:

N.A.

N.A.

21,265#
2127#

N.A.

N.A.

21,265#
2127#

Plum

Air:
Other:

2,914,870#
291,496#

124,439#
12,444#

N.A.

N.A.

23,628#
2363#

39,379#
3938#

245


-------
Maximum Current Label Rates

CaPUR

Group

RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years

Prune

Air:
Other:

30,716#
3072#

3938#
394#

N.A.

N.A.

N.A.

22,053#
2205#

Tropical/Subtropical
Fruit

Air:
Other:

N.A.

N.A.

8663#
866#

194,535#
19,454#

N.A.

140,979#
14,098#

21. Papaya

N.A.

22. Garlic and Leek

Garlic

Air:
Other:

133,920#
50,514#

109,508#
41,306#

77,423#
29,204#

134,618#
50,778#

126,945#
47,884#

130,433#
49,199#

Leek

Air:
Other:

133,920#
50,514#

133,920#
50,514#

122,063#
46,042#

119,970#
45,253#

111,600#
42,095#

125,550#
47,357#

23. Grapes

Grape

Air:
Other:

43,308#
8661#

46,079#
9215#

56,127#
11,224#

90,773#
18,153#

53,009#
10,601#

53,702#
10,739#

Wine Grape

Air:
Other:

54,394#
10,878#

54,048#
10,809#

72,064#
14,411#

59,938#
11,986#

65,828#
13,164#

57,859#
11,571#

26. Brussel Sprouts and .
Dandelion

Brussel Sprout

Air:
Other:

45,692#
9288#

94,743#
19,259#

101,463#
20,625#

80,633#
16,391#

153,874#
31,279#

78,617#
15,981#

27. Swiss Chard, Chervil, Endive
(Escarole), Lettuce, Head Lettuce,
Leaf Lettuce (Black Seeded
Simpson, Salad Bowl, Etc.), Orach
(Mountain Spinach), Parsley,
Roquette (Arrugula), Salsify, and
Spinach

Arrugula

Air:
Other:

N.A.

166,304#
81,376#

N.A.

250,755#
122,700#

265,047#
129,693#

244,259#
119,521#

Endive (Escarole)

Air:
Other:

210,479#
102,992#

197,486#
96,634#

180,596#
88,369#

180,596#
88,369#

177,997#
87,098#

196,187#
95,998#

Lettuce, Head

Air:
Other:

231,267#
113,164#

188,391#
92,184#

200,085#
97,906#

209,179#
102,356#

215,676#
105,535#

209,179#
102,356#

Lettuce, Leaf

Air:
Other:

179,297#
87,734#

183,194#
89,641#

197,486#
96,634#

201,384#
98,541#

218,274#
106,806#

192,289#
94,091#

Parsley

Air:
Other:

194,888#
95,363#

132,524#
64,847#

318,316#
155,759#

184,494#
90,277#

166,304#
81,376#

194,888#
95,363#

Spinach

Air:
Other:

205,282#
100,449#

194,888#
953,63#

192,289#
94,091#

201,384#
98,541#

187,092#
91,548#

193,588#
94,727#

Swiss Chard

Air:
Other:

220,873#
108,078#

241,661#
118,250#

179,297#
87,734#

241,661#
118,250#

190,990#
93,455#

222,172#
108,713#

28. Peppermint

Pepper, Spice

Air:
Other:

64,885#
13,248#

68,940#
14,076#

N.A.

98,003#
20,009#

N.A.

83,810#
17,112#

29. Eggplant

Eggplant

Air:
Other:

75,515#
15,247#

61,193#
12,355#

50,126#
10,121#

10,1554#
20,505#

135,406#
27,339#

100,903#
20,373#

246


-------
Maximum Current Label Rates

CaPUR

Group

RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years

30. Pumpkin

Cantaloupe

Air:
Other:

76,873#
15,376#

71,248#
14,251#

74,998#
15,001#

108,122#
21,627#

76,248#
15,251#

79,373#
15,876#

Cucumber

Air:
Other:

93,747#
18,752#

114,371#
22,877#

107,497#
21,502#

103,122#
20,627#

117,496#
23,502#

101,872#
20,377#

Pumpkin

Air:
Other:

91,247#
18,252#

102,497#
20,502#

30,624#
6126#

91,247#
18,252#

74,998#
15,001#

85,622#
17,127#

31. Cucumber, Cucurbit
Vegetables, Melons - Unspecified,
Cantaloupe, Honeydew, Musk,
Water, and Winter
(Casaba/Crenshaw/Honeydew/Pers
ian), and Squash (All Or
Unspecified)

Melon

Air:
Other:

409,795#
85,953#

156,267#
32,776#

114,769#
24,072#

241,209#
50,593#

132,276#
27,744#

164,696#
34,545#

Squash

Air:
Other:

102,449#
21,488#

105,691#
22,168#

90,129#
18,904#

102,449#
21,488#

84,942#
17,816#

98,558#
20,672#

Squash, Summer

Air:
Other:

101,800#
21,352#

106,988#
22,440#

96,613#
20,264#

106,988#
22,440#

106,339#
22,304#

104,394#
21,896#

Squash, Winter

Air:
Other:

94,019#
19,720#

12,320#
2584#

N.A.

158,861#

33,321#

99,855#
20,944#

54,466#
11,424#

Squash, Zucchini

Air:
Other:

89,481#
18,768#

N.A.

N.A.

N.A.

97,262#
20,400#

90,777#
19,040#

Watermelon

Air:
Other:

93,371#
19,584#

103,746#
21,760#

92,723#
19,448#

95,965#
20,128#

99,207#
20,808#

95,965#
20,128#

32. Onion (Unspecified and
Green), Radish, and Shallot

Chive

Air:
Other:

N.A.

N.A.

N.A.

91,498#
24,551#

79,091#
21,222#

89,947#
24,135#

Daikon

Air:
Other:

45,749#
12,275#

N.A.

N.A.

N.A.

N.A.

45,749#
12,275#

Onion, Dry

Air:
Other:

92,273#
24,759#

100,803#
27,048#

134,920#
36,202#

113,984#
30,584#

119,412#
32,041#

115,535#
31,001#

Onion, Green

Air:
Other:

137,246#
36,826#

153,530#
41,195#

131,819#
35,370#

152,755#
40,987#

167,487#
44,940#

146,551#
39,323#

Radish

Air:
Other:

117,861#
31,625#

133,369#
35,786#

138,797#
37,242#

109,332#
29,336#

148,878#
39,947#

138,797#
37,242#

Shallot

Air:
Other:

N.A.

N.A.

N.A.

N.A.

158,182#
42,444#

158,182#
42,444#

33. Potato - White/Irish

Potato

Air:
Other:

65,646#
13, 131#

51,466#
10,295#

98,731#
19,749#

107,134#
21,429#

N.A.

89,278#
17,858#

247


-------
Maximum Current Label Rates

CaPUR

Group

RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years

34. Turnip

Turnip

Air:
Other:

124,126#
24,828#

122,301#
24,463#

136,295#
27,262#

90,052#
18,013#

97,962#
19,595#

119,867#
23,976#

35. Parsnip and Rutabaga

Parsnip

Air:
Other:

N.A.

N.A.

84,543#
16,912#

N.A.

N.A.

84,543#
16,912#

36. Sweet Potato

Sweet Potato

Air:
Other:

57,419#
11,908#

334,947#
69,465#

54,584#
11,320#

76,205#
15,804#

43,242#
8968#

76,205#
15,804#

37. Bluegrass, Canarygrass, Grass
Forage/Fodder/Hay, Pastures, Peas
(Including Vines), Rangeland,
Sudangrass, and Timothy

Forage Hay/Silage

Air:
Other:

93,216#
19,260#

88,521#
18,290#

83,827#
17,320#

82,486#
17,043#

80,474#
16,628#

87,851#
18,152#

Grass, Seed

Air:
Other:

N.A.

N.A.

79,803#
16,489#

N.A.

N.A.

79,803#
16,489#

Pastureland

Air:
Other:

52,979#
10,946#

67,062#
13,856#

83,827#
17,320#

83,156#
17,182#

89,192#
18,429#

79,803#
16,489#

Rangeland

Air:
Other:

44,261#
9145#

N.A.

94,557#
19,537#

N.A.

65,720#
13,579#

48,284#
9977#

Sudangrass

Air:
Other:

N.A.

N.A.

79,803#
16,489#

N.A.

N.A.

79,803#
16,489#

40. Beets, Cowpea/Blackeyed Pea,
and Peas (Unspecified and Field)

Beet

Air:
Other:

150,608#
30,121#

186,866#
37,373#

124,113#
24,822#

141,544#
28,309#

106,681#
21,336#

154,792#
30,958#

Peas

Air:
Other:

38,349#
7670#

39,744#
7949#

67,634#
13,527#

92,039#
18,408#

48,111#
9622#

59,267#
11,853#

41. Carrot (Including Tops),
Celtuce, Fennel, and Pepper

Carrot

Air:
Other:

174,351#
34,858#

101,705#
20,334#

165,633#
33,115#

193,723#
38,731#

161,759#
32,340#

172,414#
34,470#

Fennel

Air:
Other:

197,598#
39,505#

N.A.

N.A.

147,230#
29,435#

198,566#
39,699#

175,319#
35,051#

Fruiting Pepper

Air:
Other:

95,893#
19,172#

112,359#
22,464#

134,638#
26,918#

144,324#
28,854#

123,983#
24,788#

121,077#
24,207#

42. Beans, Beans - Dried-Type,
Beans - Succulent (Lima), and
Beans - Succulent (Snap)

Dried Bean

Air:
Other:

952,43#
19,049#

57,407#
11,482#

88,067#
17,614#

78,935#
15,787#

101,767#
20,354#

76,325#
15,265#

Succulent Bean

Air:
Other:

69,802#
13,961#

83,501#
16,700#

82,196#
16,440#

85,458#
17,092#

99,157#
19,832#

80,239#
16,048#

Unspecified Bean

Air:
Other:

90,025#
18,005#

95,243#
19,049#

91,329#
18,266#

97,853#
19,571#

95,243#
19,049#

92,634#
18,527#

248


-------
Maximum Current Label Rates

CaPUR

Group

RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years

43. Celery

Celery

Air:
Other:

103,227#
52,758#

102,500#
52,387#

102,500#
52,387#

106,135#
54,244#

109,042#
55,730#

104,681#
53,501#

44. Asparagus and Safflower
(Unspecified)

Asparagus

Air:
Other:

146,031#
74,575#

177,323#
90,555#

160,373#
81,899#

159,069#
81,233#

166,892#
85,228#

155,158#
79,236#

Safflower

Air:
Other:

156,462#
79,902#

N.A.

N.A.

N.A.

N.A.

156,462#
79,902#

45. Anise

N.A.

46. Strawberry

Strawberry

Air:
Other:

165,380#
33,076#

162,727#
32,545#

163,611#
32,722#

175,108#
35,022#

183,952#
36,790#

169,802#
33,960#

47. Sugar Beet

Sugarbeet (CDPR PUR data appears to be erroneous)

48. Tomato

Tomatillo

Air:
Other:

38,364#
7671#

40,251#
8048#

36,478#
7293#

56,603#
11,317#

N.A.

42,138#
8425#

Tomato

Air:
Other:

98,112#
19,617#

80,502#
16,096#

20,126#
4024#

57,232#
11,443#

106,917#
21,377#

49,056#
9808#

Processing Tomato

Air:
Other:

72,326#
14,461#

69,810#
13,958#

69,182#
13,832#

76,729#
15,341#

88,049#
17,605#

70,439#
14,084#

49. Okra

Okra

Air:
Other:

N.A.

N.A.

N.A.

N.A.

88,573#
17,774#

88,573#
17,774#

51. Sorghum

Sorghum (Forage -
Fodder)

Air:
Other:

N.A.

1328#
266#

N.A.

N.A.

65,083#
13,017#

56,671#
11,334#

Sorghum/Milo

Air:
Other:

N.A.

N.A.

N.A.

67,740#
13,548#

N.A.

67,740#
13,548#

52. Barley, Cereal Grains, Oats,
Rye, and Wheat

Barley

Air:
Other:

148,991#
96,255#

142,157#
91,840#

146,257#
94,489#

155,826#
100,671#

146,257#
94,489#

146,257#
94,489#

Oat

Air:
Other:

173,595#
112,151#

118,920#
76,828#

135,322#
87,425#

165,394#
106,852#

154,459#
99,788#

147,624#
95,372#

Oat (Forage - Fodder)

Air:
Other:

165,394#
106,852#

162,660#
105,086#

196,832#
127,163#

102,517#
66,231#

164,027#
105,969#

151,725#
98,022#

Wheat

Air:
Other:

140,790#
90,957#

139,423#
90,074#

133,955#
86,542#

140,790#
90,957#

135,322#
87,425#

138,056#
89,191#

Wheat (Forage -
Fodder)

Air:
Other:

N.A.

170,862#
110,385#

136,689#
88,308#

131,222#
84,775#

132,589#
85,658#

143,524#
92,723#

53. Gooseberry

N.A.

249


-------
Maximum Current Label Rates

CaPUR

Group



RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years

54. Blackberry, Boysenberry,
Dewberry, Loganberry, and
Raspberry (Black - Red)

Blackberry

Air:
Other:

260,176#
52,029#

256,327#
51,260#

213,991#
42,793#

265,564#
53,107#

264,794#
52,953#

250,939#
50,182#

Raspberry

Air:
Other:

94,679#
18,934#

99,298#
19,857#

111,614#
22,320#

139,325#
27,862#

99,298#
19,857#

109,305#
21,858#

55. Blueberry

Blueberry

Air:
Other:

127098#
25460#

166006#
33254#

188486#
37758#

86462#
17320#

N.A.

186,757#
37,411#

56. Caneberries and Currant

N.A.

57. Passion Fruit (Granadilla)

N.A.

58. Mint and Spearmint

Mint

Air:
Other:

50,748#
10,150#

51,331#
10,266#

57,747#
11,549#

54,831#
10,966#

52,498#
10,500#

55,414#
11,083#

59. Rice and Wild Rice

Rice

Air:
Other:

8,946,531#

9,486,408#

11,723,041#

N.A.

11,491,665#

10,103,410#

Wild Rice

Air:
Other:

13,574,048#

11,414,540#

11,414,540#

8,406,655#

11,183,164#

11,183,164#

61. Water Cress

Watercress

Air:
Other:

8,329,529#

7,481,151#

9,023,657#

8,406,655#

7,326,901#

8,252,404#





Non-agricultural

Uses









Forestry. Christmas Tree
Plantations, Pine (Seed Orchard),
and Slash Pine (Forest)

Christmas Tree

Air:
Other:

N.A.

N.A.

513,087#
428,742#

1,303,659#
1,089,354#

363,000#
303,328#

607,327#
507,490#

Mosquito Control. Intermittently
Flooded Areas/Water,
Lakes/Ponds/Reservoirs (with
Human or Wildlife Use),
Lakes/Ponds/Reservoirs (without
Human or Wildlife Use), Polluted
Water, and

Swamps/MarshesAV etlands/Stagna
nt Water

N.A.

Nursery. Outdoor Nursery

N-Outdoor Flower

Air:
Other:

135,669#
27,242#

88,107#
17,692#

49,122#
9863#

58,478#
11,742#

87,327#
17,535#

84,988#
17,065#



N-Outdoor Plants In
Containers

Air:
Other:

77,191#
15,500#

41,325#
8298#

133,330#
26,772#

146,585#
29,434#

136,449#
27,398#

90,446#
18,161#

250


-------
Maximum Current Label Rates

CaPUR

Group



RQ (Estimated)

Crop/Site

Crop/Site

Method1

2001

2002

2003

2004

2005

All Years



N-Outdoor Transplants

Air:
Other:

215,980#
43,368#

145,806#
29,277#

141,127#
28,338#

116,956#
23,484#

134,110#
26,929#

173,875#
34,913#

Public Health and Medfly
Control. Nonagricultural Areas
(Public Health Use), Urban Areas,
and Wide Area/General Outdoor

Buildings/Non-Ag
Outdoor





Not reported on a lbs. ai/A basis.





Treatment (Public Health Use)

















Residential. Household/Domestic

















Dwellings Outdoor Premises,

















Ornamental and/or Shade Trees,

















Ornamental Herbaceous Plants,
Ornamental Lawns and Turf,

Landscape
Maintenance

Other:

N.A.

N.A.

19,224#

37,097#

11,715#

19,374#

Ornamental Non-flowering Plants,
Ornamental Woody Shrubs and

















Vines, and Urban Areas

















Right-of-ways. Nonagricultural
Rights-of-

way/Fencerows/Hedgerows and
Nonagricultural Uncultivated
Areas/Soils

Rights Of Way

Air:
Other:

N.A.

N.A.

N.A.

63,555#
12,715#

N.A.

63,555#
12,715#

Uncultivated Ag

Air:
Other:

12,301#
2461#

N.A.

N.A.

30,240#
6050#

60,480#
12,100#

30,753#
6153#

Uncultivated Non-Ag

Air:
Other:

92,771#
18,560#

121,986#
24,405#

N.A.

N.A.

N.A.

99,434#
19,893#

Turf. Golf Course Turf

Bermudagrass

Air:
Other:

58,532#
11,707#

57,979#
11,596#

65,158#
13,032#

72,888#
14,578#

59,084#
11,817#

62,397#
12,480#

1 "Air" refers to aerial and air-blast application methods for which EFED policy assumes 5% spray drift when estimating environmental concentrations. "Other"
refers other application methods for which EFED policy assumes 1% spray drift.

# Chronic RQ >1.0 for listed and unlisted species.

251


-------
6.1.3	Timing of Malathion Applications

The choice of application dates made for this assessment may bias the assessment results
to be less conservative {i.e., less protective of the CRLF). This is because the application
time period (the simulated first through last application dates) may cover only a small
portion of the time period over which malathion is applied in California (Figure 9) or can
be legally applied {e.g., year-round for labels that do not have temporal restrictions).
Malathion is applied in every month of the year (Figure 2). Because rain is more frequent
in the winter for many of the scenarios while the peak malathion applications tend to
occur in the summer, many of the scenarios will generate a much lower runoff
contribution to EEC than would happen during other earlier or later times of the year
when malathion is being applied to that use (Figure 10).

6.1.4	Impact of Vegetative Setbacks on Runoff

EFED does not currently have an effective tool to evaluate the impact of vegetative
setbacks on runoff and pesticide loadings. The effectiveness of such setbacks is highly
dependent on the condition of the vegetative strip. A well-established, healthy vegetative
setback can be a very effective means of reducing runoff and erosion from agricultural
fields and may substantially reduce loading to aquatic ecosystems. However, a setback
that is narrow, of poor vegetative quality, or channelized is likely to be ineffective at
reducing loadings. The presence and quality of setbacks are site-specific, and may vary
widely, even within a small geographic area. EFED does not currently incorporate any
"buffer reduction" in its exposure estimates. Until such time as quantitative methods to
estimate the effect of vegetative setbacks of various conditions on pesticide loadings
become available, EFED's aquatic exposure predictions are likely to overestimate
exposure where healthy vegetative setbacks exist and may underestimate exposure where
poorly developed, channelized or no setbacks exist.

6.1.5	PRZM Modeling inputs and Predicted Aquatic Concentrations

EFED currently typically uses the linked PRZM/EXAMS model which produces
estimated aquatic concentrations based on site conditions and historical meteorological
files (generally 30-year). The "peak" pesticide concentration used in the assessment is
probability-based, and is expected to be exceeded once within a ten-year period. PRZM is
a process-based "simulation" model, which calculates what happens to a pesticide in a
farmer's field on a day-to-day basis. It considers factors such as rainfall and plant
transpiration of water, as well as how and when the pesticide is applied. The two major
components are hydrology and chemical transport. Water movement in and off the field
is simulated by the use of generalized soil parameters, including field capacity, wilting
point, and saturation water content. Soils in each scenario are selected to represent high
availability conditions for the pesticide. The chemical transport component simulates the
method of pesticide application on the soil or on the plant foliage and the environmental
processes acting on the pesticide. Dissolved, adsorbed, and vapor-phase concentrations in
the soil are estimated by simultaneously considering the processes of pesticide uptake by
plants, surface runoff, erosion, decay, volatilization, foliar wash-off, advection,
dispersion, and retardation.

252


-------
Uncertainty associated with each of these individual components adds to the overall
uncertainty of the modeled concentrations. Equations in the model have not been shown
to exert any directional bias. Model inputs from the required environmental degradation
studies are chosen to represent the upper confidence bound of the mean, and are not
expected to be exceeded in the environment 90% of the time. Mobility input values are
selected to be representative of conditions in the open environment. Natural variation in
soils adds to the uncertainty of modeled values. Factors such as application date, crop
emergence date, and canopy cover can affect estimated concentrations. Ambient
environmental factors, such as soil temperatures, sunlight intensity, antecedent soil
moisture, and surface water temperatures may cause actual aquatic concentrations to
differ from the modeled values.

The quality of the analysis is directly related to the quality of the input parameters. Most
of the fate data for malathion is complete, however, there is little fate and transport data
on toxic impurities and degradates such as maloxon. In addition, the aquatic persistence
inputs were derived from studies conducted under alkaline conditions which would be
likely to increase degradation rates and reduce the conservatism of this analysis.

Most of the uncertainties described pertain to the runoff and groundwater contributions to
the total EECs generated by PRZM/EXAMS. Because EECs for many scenarios in this
assessment are dominated by the drift contributions to the total EEC, the PRZM input
that likely most impacts this assessment is the spray drift fraction. EFED policy specifies
that aerial and air blast methods are modeled with a 5% spray drift fraction, while other
application methods are modeled with a 1% spray drift fraction.

Under actual field conditions, the spray drift fraction can be much higher especially with
ultra-low volume (ULV) formulations. ULV formulations are highly prone to drift when
applied aerially, but are popular with aerial applicators because they are very
concentrated and allow the treatment of large acreage without returning to the airfield for
refilling or refueling.

An assessment of drift from malathion use was conducted for the Boll Weevil
Eradication Program by measuring off-target drift adjacent to aerial ULV malathion
applications (Pennsylvania State University 1993).14 Maximum depositions were 21, 12,
2.8, and 0.7% of the expected maximum at 100, 200, 300, and 1000 m downwind
(Pennsylvania State University 1993). The highest amount of drift at 1 km occurred when
atmospheric conditions were stable, meaning vertical air mass movements are dampened.
Higher drift levels at shorter distances occurred under unstable, windy conditions.
Averages of results under different atmospheric conditions show deposition of 9.4% at
100 m while at 1000 m the deposition rate was 0.08%.

14 Application conditions were the same as those used in the eradication program. The spray system was a
conventional boom and nozzle system fitted with Spraying Systems stainless steel 8002 Flat Fan spray tips.
The nozzle position was straight down and the flying height was a nominal 5 feet above the crop canopy.
Drift was measured from single aircraft passes delivering 1 lb/A. Wind direction was perpendicular to the
flight path. Seventeen runs were conducted under varying meteorological conditions.

253


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6.2 Effects Assessment Uncertainties

6.2.1	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. For guideline tests, young (and theoretically more
sensitive) organisms are used. Testing of juveniles may overestimate toxicity at older age
classes for active ingredients of pesticides which act directly (without metabolic
transformation) on the organism, because younger age classes often have not developed
enzymatic systems associated with the detoxification of xenobiotics. When the available
toxicity data provides a range of sensitivity information with respect to age class, the risk
assessors use the most sensitive life-stage information as measures of effect.

6.2.2	Extrapolation of Effects

Length of exposure and concurrent environmental stressors (e.g., urban expansion,
habitat modification, and predators) will likely affect the response of the CRLF to
malathion. Because of the complexity of an organism's response to multiple stressors, the
overall "direction" of the response is unknown. Additional environmental stressors may
decrease or increase the sensitivity to the herbicide. Timing, peak concentration, and
duration of exposure are critical in terms of evaluating effects, and these factors will vary
both temporally and spatially within the action area. Overall, the effect of this variability
may result in either an overestimation or underestimation of risk.

6.2.3	Acute LOC Assumptions

The risk characterization section of this assessment includes an evaluation of the potential
for individual effects. The individual effects probability associated with the acute RQ is
based on the assumption that the dose-response curve fits a probit model. It uses the mean
estimate of the slope and the LC50 to estimate the probability of individual effects.

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