Risks of Mancozeb and Maneb Uses to the 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 18, 2007
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Primary Authors
Jean Holmes, D.V.M., M.P.H.
Mohammed Ruhman, Ph.D, Agronomist
Secondary Review
Tom Steeger, Ph.D, Senior Biologist
Faruque Khan, Ph.D, Senior Scientist
Branch Chief, Environmental Risk Assessment Branch 5
Mah Shamim, Ph.D
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Table of Contents
1 Executive Summary 9
2 Problem Formulation 13
2.1 Purpose 13
2.2 Scope 15
2.3 Previous Assessment 16
2.4 Stressor Source and Distribution 17
2.4.1 Environmental Fate and Transport Assessment 17
2.4.2 Mechanism of Action 21
2.4.3 Use Characterization 21
2.5 Assessed Species 35
2.5.1 Distribution 35
2.5.1.1 Recovery Units 36
2.5.1.2 Core Areas 39
2.5.1.3 Other Known Occurrences from the CNDBB 39
2.5.2 Reproduction 39
2.5.3 Diet 40
2.5.4 Habitat 41
2.6 Designated Critical Habitat 41
2.7 Action Area 43
2.8 Assessment of Endpoints and Measures of Ecological Effect 49
2.8.1 Assessment Endpoints for the CRLF 49
2.8.2 Assessment Endpoints for Designated Critical Habitat 51
2.9 Conceptual Model 54
2.9.1 Risk Hypothesis 54
2.9.2 Diagram 54
2.10 Analysis Plan 59
2.10.1 Measures of Exposure 61
2.10.2 Measures of Effect 61
2.10.3 Measures of Risk 62
2.10.4 How Uncertainties are addressed in this Risk Assessment 63
3 Exposure Assessment 65
3.1 Aquatic Exposure Assessment 65
3.1.1 Aquatic Exposure Modeling 65
3.1.1.1 Modeling Approach 65
3.1.1.2 Modeling Inputs 65
3.1.1.3 Modeling Results 69
3.1.2 Aquatic Monitoring 71
3.1.3 Down-stream Dilution Analysis 71
3.2 Terrestrial Animal Exposure Assessment 72
3.2.1 Terrestrial Exposure Modeling 72
3.3.2 Terrestrial Atmospheric Monitoring 74
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3.2.3 Drift Analysis 74
4 Effects Assessment 76
4.1 Toxicity of Mancozeb, Maneb and ETU to Aquatic Organisms 77
4.1.1 Toxicity to Freshwater Vertebrates (Amphibians and Fish) 78
4.1.1.1 Aquatic-Phase Amphibians: Acute Exposure (Mortality) Studies 78
4.1.1.2 Aquatic-Phase Amphibians: Chronic Exposure (Growth, Reproduction) Studies 78
4.1.1.3 Freshwater Fish: Acute Exposure (Mortality) Studies 79
4.1.1.4 Freshwater Fish: Chronic Exposure (Growth, Reproduction) Studies 79
4.1.1.5 Freshwater Vertebrates: Sub-lethal Effects 79
4.1.2 Toxicity to Freshwater Invertebrates 80
4.1.2.1 Freshwater Invertebrates: Acute Exposure (Mortality) Studies 80
4.1.2.2 Freshwater Invertebrates: Chronic Exposure (Growth, Reproduction) Studies 80
4.1.3 Toxicity to Aquatic Plants 81
4.1.4 Freshwater Field Studies 81
4.2 Toxicity of Mancozeb and Maneb to Terrestrial Organisms 82
4.2.1 Toxicity to Birds 83
4.2.1.1 Birds: Acute Exposure (Mortality) Studies 83
4.2.1.2 Birds: Chronic Exposure (Growth, Reproduction) Studies 84
4.2.2 Toxicity to Mammals 84
4.2.2.1 Mammals: Acute Exposure (Mortality) Studies 84
4.2.2.2 Mammals: Chronic Exposure (Growth, Reproduction) Studies 85
4.2.2.3 Mammals - Sub-lethal effects 86
4.2.3 Toxicity to Terrestrial Invertebrates 86
4.2.3.1 Terrestrial Invertebrates: Acute Exposure (Mortality) Studies 86
4.2.4 Toxicity to Terrestrial Plants 86
4.2.5 Terrestrial Field Studies 87
4.3 Use of Probit Slope Response Relationship to Provide Information on the Endangered Species Levels
of Concern 87
4.4 Incident Database Review 88
4.4.1 Terrestrial Incidents 88
4.4.2 Plant Incidents 88
4.4.3 Aquatic Incidents 88
5 Risk Characterization 90
5.1 Risk Estimation 90
5.1.1 Direct Effects to the CRLF 92
5.1.1.1 Aquatic-phase of the CRLF 92
5.1.1.2 Terrestrial-phase of the CRLF 94
5.1.2 Indirect Effects to the CRLF 95
5.1.2.1 Evaluation of Potential Indirect Effects via Reduction in Food Items (Freshwater Fish) 95
5.1.2.2 Evaluation of Potential Indirect Effects via Reduction in Food Items (Freshwater
Invertebrates) 97
5.1.2.3 Evaluation of Potential Indirect Effects for the aquatic-phase CRLF via Reduction in Food
Items (freshwater aquatic plants) 100
5.1.2.4 Evaluation of Potential Indirect Effects via Reduction in Food Items (Small Mammals) 102
5.1.2.5 Evaluation of Potential Indirect Effects via Reduction in Food Items (Terrestrial Invertebrates)
103
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5.1.3 Effects to Primary Constituent Elements of Designated Critical Habitat 103
5.1.3.1 Aquatic-Phase (Aquatic Breeding Habitat and Aquatic Non-Breeding Habitat) 103
5.1.3.2 Terrestrial-Phase (Upland Habitat and Dispersal Habitat) 104
5.2 Risk Description 106
5.2.1 Introduction 106
5.2.2 Effects Determination 106
5.2.3 Direct Effects 120
5.2.3.1 Aquatic-phase 120
5.2.3.2 Terrestrial-phase 123
5.2.4 Indirect Effects (through effects to prey) 124
5.2.5 Indirect Effects (through effects to habitat) 128
5.2.6 Primary Constituent Elements of Designated Critical Habitat 128
5.2.6.1 Aquatic-Phase (Aquatic breeding habitat and aquatic non-breeding habitat) 128
5.2.6.2. Terrestrial-Phase (upland habitat and dispersal habitat) 129
6 Uncertainties 130
6.1 Exposure Assessment Uncertainties 130
6.1.1 Maximum Use Scenario 130
6.1.2 Joint Mancozeb/Maneb Use 130
6.1.3 Action Area Overlap with Species Range 130
6.1.4 CDPR Usage Information 130
6.1.5 Aquatic Exposure 131
6.1.5.1 Models and Model Inputs 131
6.1.5.2 Long-term Chronic Exposure 131
6.1.5.3 Timing of Application 132
6.1.5.4 Multiple Cropping 133
6.1.5.5 Seed Treatment 133
6.1.5.6 Irrigation Scenarios 134
6.1.5.7 Exposure to Trace Elements 134
6.1.5.8 Action Area 135
6.1.5.9 Aquatic Exposure Estimates 135
6.1.6 Terrestrial Exposure 136
6.1.6.1 Incidental Releases Associated With Use 136
6.1.6.2 Residue Levels Selection 136
6.1.6.3 Dietary Intake 137
6.1.6.4 Location of Wildlife Species 138
6.2 Effects Assessment Uncertainties 138
6.2.1 Estimated Effects Endpoints 138
6.2.1.1 Use of Acute-to- Chronic Ratio Approach 138
6.2.1.2 Use of Surrogate Data for Terrestrial-Phase Amphibians 138
6.2.1.3 Use of Surrogate Data for Aquatic-Phase Amphibians 138
6.2.2 Aquatic Plant Effects 138
6.2.3 Terrestrial Plant Effects 139
6.2.4 Sub-lethal Effects 139
6.3.5 Age Class and Sensitivity of Effects Thresholds 139
7 References 140
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Appendices
Appendix A: Product Formulations Containing Multiple Active Ingredients for Mancozeb and Maneb
Appendix B: Additional County-Level Usage Data
Appendix C: Spatial Summary for Mancozeb Uses
Appendix D: Reviewed Toxicity Data (Registrant and Open Literature)
Appendix E: T-HERPS Modeling: Terrestrial Exposure Estimates and Risk Quotients
Appendix F: T-REX Modeling: Terrestrial Exposure Estimates and Risk Quotients
Appendix G: Summary of Input Parameters Used in AgDISP for Estimation of Buffers.
Appendix H: List of Citations Accepted and Rejected by ECOTOX Criteria.
Appendix I: Spatial Summary for Maneb Uses
Appendix J: Ecological Incidents Data in the United States
Appendix K: TerrPlant Modeling: Estimation of Exposures to CRLF Terrestrial-phase Habitat
Appendix L: Spatial Summary for Mancozeb and Maneb Uses
Attachments
Attachment 1: CRLF Life History
Attachment 2: CRLF Baseline Status and Cumulative Effects
List of Tables
Table 2-1 Chemical identity and laboratory measured physiochemical and abiotic fate properties for
mancozeb and maneb. 18
Table 2-2 Laboratory measured fate properties for the mancozeb and maneb complexes including their major
degradate, ETU. 19
Table 2-3 Chemical identity and laboratory measured physiochemical properties of ETU. 19
Table 2-4 Maximum ETU produced in fate studies for parent EBDCs. 20
Table 2-5 Risk mitigation measures included in the mancozeb and maneb REDs. 22
Table 2-6 Mancozeb use patterns in California (MSR= maximum single rate (lb a.i./acre), MNA= maximum
number of applications, MTR= maximum total rate (lb a.i./acre/crop cycle or year), and MAI=
minimum re-application intervals in days). 23
Table 2-7 Additional mancozeb use patterns in California: Dip and pre-plant seed treatments (Maximum
application rate; all are single rates) 24
Table 2-8 Maneb use patterns in California (MSR= maximum single rate (lb a.i./acre). MNA= maximum
number of applications, MTR= maximum total rate (lb a.i./acre/crop cycle or year), and MAI=
minimum re-application intervals in days). 25
Table 2-9 Additional maneb use patterns in California: dip and pre-plant seed treatments (maximum
application rate; all are single rates). 26
Table 2-10 California usage data for mancozeb 29
Table 2-11 California usage data for maneb 31
Table 2-12 Combined usage data for mancozeb and maneb showing the % share for each 33
Table 2-13 CRLF Recovery Units with Overlapping Core Areas and Designated Critical Habitat 36
Table 2-14 Summary of use patterns for mancozeb and maneb alone and maneb and mancozeb together 44
Table 2-15 Summary of assessment endpoints and measures of ecological effects for direct and indirect
effects of mancozeb/maneb on the CRLF 50
Table 2-16 Summary of assessment endpoints and measures of ecological effect for primary constituent
elements of the CRLF designated critical habitat 52
Table 3-1 Representative scenarios and application parameters 66
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Table 3-2 PRZM/EXAMS Input parameters for mancozeb and maneb for the short and long term simulations
67
Table 3-3 EECs for the short and long-term constituents of the EBDC complex resulting from mancozeb and
maneb (ppb) 69
Table 3-4 A summary of the highest RQ to LOC ratios for various use categories 72
Table 3-5 T-REX model inputs for Mancozeb and Maneb uses; Half-life was assumed to be 20 days1 for all
uses 73
Table 3-6 A summary of buffer distances obtained by AgDISP along with important parameters used in
modeling (species used for calculating RQs is laboratory rat). 74
Table 4-1 Aquatic Toxicity Profile for mancozeb, Maneb, and ETU 77
Table 4-2 Categories of Acute Toxicity for Aquatic Animals 77
Table 4-3 Chronic toxicity of ETU to freshwater invertebrates during a life-cycle toxicity test 79
Table 4-4 Acute toxicity of ETU to freshwater fish and invertebrates 79
Table 4-5 Chronic toxicity of ETU to aquatic-phase amphibians 79
Table 4-6 Chronic toxicity of ETU to freshwater invertebrates during a life-cycle toxicity test 81
Table 4-7 Toxicity of Penncozeb 80 WP to various aquatic species 82
Table 4-8 Terrestrial toxicity profile for mancozeb and maneb 83
Table 4-9 Qualitative descriptors for avian and mammalian acute toxicity 83
Table 4-10 Mammalian acute oral toxicity for mancozeb 85
Table 4-11 Mammalian acute toxicity for maneb 85
Table 5-1 RQ calculation methodology and LOC values 91
Table 5-2 Direct effect acute RQs for the aquatic-phase CRLF, mancozeb-maneb jointly used 92
Table 5-3 Direct effect RQs for the aquatic-phase CRLF, mancozeb used alone 93
Table 5-4 Direct effect RQs for the aquatic-phase CRLF, maneb used alone 93
Table 5-5 Direct effect RQs for the aquatic-phase CRLF, mancozeb and maneb all uses (highest long-term
constituent exposure concentration) 94
Table 5-6 Direct effect dietary-based chronic RQs for the terrestrial-phase CRLF 94
Table 5-7 Indirect effects for the aquatic-phase CRLF via acute effects on freshwater fish, joint mancozeb-
maneb application uses 95
Table 5-8 Indirect effects for the aquatic-phase CRLF via acute effects to freshwater fish, mancozeb
application only uses 96
Table 5-9 Indirect effects for the aquatic-phase CRLF via acute effects to freshwater fish, maneb application
only uses 96
Table 5-10 Indirect effects for the aquatic-phase CRLF via chronic effects to freshwater fish, all mancozeb
and maneb uses (highest long-term constituent exposure concentration) 97
Table 5-11 Indirect effects for the aquatic-phase CRLF via acute effects to freshwater invertebrates, joint
mancozeb-maneb application uses 98
Table 5-12 Indirect effects for the aquatic-phase CRLF via effects to freshwater invertebrates, mancozeb only
application uses 98
Table 5-13 Indirect effect RQs for the aquatic-phase CRLF, via direct effects to freshwater invertebrates,
maneb application uses 99
Table 5-14 Indirect effect RQs for the aquatic-phase CRLF, via chronic effects to freshwater invertebrates,
all mancozeb and maneb uses (highest long-term constituent exposure concentration 100
Table 5-15 Indirect effects for the aquatic-phase CRLF via effects to freshwater aquatic plants, joint
mancozeb-maneb application uses 100
Table 5-16 Indirect effects for the aquatic-phase CRLF via effects to freshwater aquatic plants, mancozeb
only application uses 101
Table 5-17 Indirect effects for the aquatic-phase CRLF via effects to freshwater aquatic plants, maneb only
application uses 101
Table 5-18 Indirect effects for the terrestrial-phase CRLF via dietary-based exposure effects to mammals 102
Table 5-19 Indirect effect RQs for the terrestrial-phase CRLF via direct effects to terrestrial invertebrates 103
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Table 5-20 Effects determination summary for direct and indirect effects of mancozeb and maneb on the
CRLF 107
Table 5-21 Effects determination summary for the critical habitat impact analysis 113
Table 5-22 Mancozeb and maneb use-specific direct effects determinations1 118
Table 5-23 Mancozeb and maneb use-specific indirect effects determinations1 based on effects to pray 119
Table 5-24 Mancozeb and maneb uses that exceed the endangered species LOC (based on freshwater fish
toxicity data) 121
Table 5-25 Direct CRLF Effects- upper bound Kenaga chronic terrestrial Herpetofauna RQs (from T-
HERPS) 123
Table 5-26 Mancozeb and maneb uses that exceed the endangered species LOC (based on freshwater
invertebrate toxicity data) 125
Table 5-27 Indirect CRLF Effects- upper bound Kenaga chronic terrestrial Herpetofauna RQs (from T-
HERPS) 127
Table 6-1 Comparison between application rates and EECs for foliar spray and seed treatment (ST) 134
Table 6-2 Monitored Mn and Zn concentrations in CA surface waters (USGS/NAWQA data) 134
List of Figures
Figure 2-1 Important crop use patterns for mancozeb 30
Figure 2-2 Important crop use patterns for maneb 32
Figure 2-3 Mancozeb and maneb reported usage data in relation to CRLF (county level data/average of five
years) 34
Figure 2-4 Recovery unit, core area, critical habitat, and occurrence designations for CRLF 38
Figure 2-5 CRLF Reproductive Events by Month 40
Figure 2-6 Initial area of concern for the use of mancozeb alone 46
Figure 2-7 Initial area of concern for the use of maneb alone 47
Figure 2-8 Initial area of concern for the interchangeable use of mancozeb or maneb 48
Figure 2-9 Conceptual model for pesticide effects on aquatic phase of the CRLF 55
Figure 2-10 Conceptual model for pesticide effects on terrestrial phase of the CRLF 56
Figure 2-11 Conceptual model for pesticide effects on aquatic components of the CRLF critical habitat 57
Figure 2-12 Conceptual model for pesticide effects on terrestrial components of the CRLF critical habitat....58
Figure 2-13 Summary of how modeled acute and chronic exposures in aquatic systems (acute and chronic
EECs) were chosen so that they can be related to laboratory measured acute and chronic effects. .61
Figure 6-1 Effect of application timing on modeled EECs for tomatoes 133
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1 Executive Summary
The purpose of this assessment is to make an "effects determination" by evaluating the potential
direct and indirect effects of the fungicides, mancozeb and maneb, on the survival, growth, and
reproduction of the California red legged frog (Rana aurora draytonii). In addition, this assessment
evaluates the potential for mancozeb and maneb uses to result in the modification of designated
critical habitat for the California red legged frog (CRLF). 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 is
consistent with procedures and methodology outlined in the Overview Document (U.S. EPA 2004)
and reviewed by the U.S. Fish and Wildlife Service and National Marine Fisheries Service
(USFWS/NMFS 2004).
The CRLF was listed as a threatened species by USFWS in 1996. The species is endemic to
California and Baja California (Mexico) and inhabits both coastal and interior mountain ranges. 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) in
California.
Mancozeb and maneb are members of the ethylene-bis-dithio-carbamate group of fungicides
(EBDCs). The two EBDCs are non-systematic preventive fungicides with wide use patterns
throughout the United States. The use patterns of the two chemicals include: row, field and
vegetable crops, orchards and vines, nursery and greenhouse, turf, and forestry. Use patterns are
either for mancozeb alone, maneb alone, or can be interchanged between mancozeb and maneb. In
addition, mancozeb and maneb can be used as seed or dip treatment for seed and seed pieces. The
total number of federally registered products that can be used in California is 55 for mancozeb and
25 for maneb.
This assessment is unique as it covers two chemicals (mancozeb and maneb) with similar complex
polymer chemistry. The decision to combine the two EBDCs in one assessment was based on the
fact that both degrades into similar chemical species (though at varied rates), can be used
interchangeably on one third of the use patterns, and most importantly produce a common degradate
ethylenethiourea (ETU); a carcinogen. ETU is of human health concern and therefore it played an
import role in regulatory decisions concerning use of the EBDCs (e.g., maximum seasonal or yearly
labeled uses for mancozeb were set as maximum for EBDCs not mancozeb).
Parent mancozeb and parent maneb are applied under moist conditions (rain and/or irrigation-fed
growing plants). Under such conditions, the two chemicals reaching the soil system are expected to
be short lived due to their hydrolytic instability (hydrolysis half-life in hours). Therefore
environmental exposure will result from chemical species produced by hydrolysis of mancozeb and
maneb, which is the EBDC complex1. Given these factors, a process was implemented to arrive at
1 The term EBDC complex is used to refer to a complex of multi chemicals that results from hydrolysis of either
mancozeb or maneb. This EBDC complex forms from mancozeb and maneb and based on fate studies and media of
formation, the suite of chemicals includes the following two categories: (1) chemicals associated with the short-term
acute exposure potential which includes variable/low molecular weight polymeric chains and short-lived transient
chemicals; and (2) chemicals associated with the long-term chronic exposure potential which includes ETU and ETU
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the EBDCs acute and chronic exposure that can be closely related to submitted measures of acute
and chronic effects (acute and chronic toxicity data). The process is presented in details elsewhere
in this document (refer to section 2.10). The process is based on estimations of acute and chronic
exposure to the chemicals present "in the EBDC complex" at the short-term for the potential acute
exposure and for chemicals present "in the EBDC complex" at the long-term for the potential
chronic exposure. The environmental fate properties of the two chemicals indicate that spray drift
and run-off represent potential transport mechanisms of parents and resultant EBDC complex into
the aquatic and terrestrial habitats of the CRLF. In this assessment, transport of parent mancozeb
and maneb from initial application sties through spray drift and runoff are considered in deriving
quantitative estimates of exposure to the CRLF, its prey and its habitats.
Since CRLFs exist within aquatic and terrestrial habitats, exposure of the CRLF, its prey and its
habitats to mancozeb and maneb are assessed separately for the two habitats. Tier-II aquatic
exposure models are used to estimate high-end exposures of the EBDC complex in aquatic habitats
resulting from runoff and spray drift from different uses. Peak model-estimated environmental
concentrations of the EBDC complex resulting from the different mancozeb and maneb major uses
range from 0.7 to 132 ppb depending on whether mancozeb or maneb is used. To estimate
mancozeb and maneb exposures to the terrestrial-phase CRLF, and its potential prey resulting from
uses involving mancozeb and maneb applications, the T-REX model is used. AgDRIFT and
AgDISP are also used to estimate potential deposition of the two EBDCs on terrestrial habitats from
spray drift. The TerrPlant model is used to estimate exposures to terrestrial-phase habitat, including
plants inhabiting semi-aquatic and dry areas, resulting from foliar application.
The assessment endpoints for the CRLF include direct toxic effects on the survival, reproduction,
and growth of the CRLF itself, as well as indirect effects, such as reduction of the prey base and/or
modification of its habitat. Direct effects to the CRLF in the aquatic habitat are based on toxicity
information for freshwater fish, which are generally used as a surrogate for aquatic-phase
amphibians. In the terrestrial habitat, direct effects are based on toxicity information for birds,
which are used as a surrogate for terrestrial-phase amphibians. Given that the CRLF's prey items and
designated critical habitat requirements in the aquatic habitat are dependant on the availability of
freshwater aquatic invertebrates, fish and aquatic plants, toxicity information for these taxonomic
groups is also discussed. In the terrestrial habitat, indirect effects due to depletion of prey are
assessed by considering effects to terrestrial insects, small terrestrial mammals, and frogs. Indirect
effects due to modification of the terrestrial habitat are characterized by available data for terrestrial
monocots and dicots.
Risk quotients (RQs) are derived as quantitative estimates of potential high-end risk. Acute and
chronic RQs are compared to the Agency's levels of concern (LOCs) to identify instances where
mancozeb and maneb use within the action area has the potential to adversely affect the CRLF and
its designated critical habitat via direct toxicity or indirectly based on direct effects to its food supply
(i.e., freshwater invertebrates, algae, fish, frogs, terrestrial invertebrates, and mammals) or habitat
(i.e., aquatic plants and terrestrial upland and riparian vegetation). When RQs for a particular type
of effect are below LOCs, the pesticide is determined to have "no effect" on the subject species.
Where RQs exceed LOCs, a potential to cause adverse effects is identified, leading to a conclusion
degradates. In the presence of soil or sediment particles part of the chemical species partitions into the solid phase and
are referred to as bound species.
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of "may affect." If a determination is made that a use pattern, within the action area, "may affect"
the CRLF and its designated critical habitat, additional information is considered to refine the
potential for exposure and effects, and the best available information is used to distinguish those
actions that "may affect, but are not likely to adversely affect" (NLAA) from those actions that are
"likely to adversely affect" (LAA) the CRLF and its critical habitat.
Based on the conclusions of this assessment a "likely to adversely affect" determination is made for
some of the mancozeb and maneb use patterns within the action area for; 1) direct effects to aquatic
and terrestrial phase CRLF; 2) indirect effects to aquatic-phase CRLF via direct effects to food
supply (i.e., freshwater invertebrates, non-vascular plants), and indirect effects on habitat (i.e.,
aquatic and terrestrial plants); 3) indirect effects to terrestrial-phase CRLF via direct effects on prey
(i.e., terrestrial invertebrates, small terrestrial vertebrates, including mammals and terrestrial phase
amphibians), indirect effects on habitat (i.e., riparian vegetation), 4) aquatic breeding habitat and
aquatic non-breeding habitat modification, and 5) upland and dispersal habitat modification. A "no
effect" determination to the CRLF is made for all mancozeb and maneb seed and dip treatment uses.
Since some of the mancozeb and maneb use patterns result in a "LAA" determination; the overall
CRLF effects determination for mancozeb and maneb use is "LAA".
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
species and its resources (i.e., food and habitat) are not expected to be uniform across the action
area. In fact, given the assumptions of drift and downstream transport (i.e., attenuation with
distance), pesticide exposure and associated risks to the species and its resources are expected to
decrease with increasing distance away from the treated field or site of application. Evaluation of
the implication of this non-uniform distribution of risk to the species 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 quantitative extrapolation of the present risk assessment's predictions of individual
effects to the proportion of the population extant within geographical areas where those effects
are predicted. Furthermore, such population information would allow for a more comprehensive
evaluation of the significance of potential resource impairment to individuals of the species.
• Quantitative information on prey base requirements for individual aquatic- and terrestrial-phase
frogs. While existing information provides a preliminary picture of 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 ultimately establish geographical limits to those effects. This
information could be used together with the density data discussed above to characterize the
likelihood of adverse effects to individuals.
• Information on population responses of prey base organisms to the pesticide. Currently,
methodologies are limited to predicting exposures and likely levels of direct mortality, growth or
reproductive impairment immediately following exposure to the pesticide. The degree to which
repeated exposure events and the inherent demographic characteristics of the prey population
play into the extent to which prey resources may recover is not predictable. An enhanced
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understanding of long-term prey responses to pesticide exposure would allow for a more refined
determination of the magnitude and duration of resource impairment, and together with the
information described above, a more complete prediction of effects to individual frogs and
potential adverse modification to critical habitat.
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2 Problem Formulation
Problem formulation provides a strategic framework for the ecological 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. 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 is consistent with procedures and methodology outlined in the
Overview Document (U.S. EPA 2004) and reviewed by the U.S. Fish and Wildlife Service and
National Marine Fisheries Service (USFWS/NMFS 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 (Rana aurora draytonii) arising from FIFRA
regulatory actions regarding use of mancozeb and maneb on a variety of row, field, and vegetable
crops, orchards and vines, ornamentals, turf, forestry, seed, and dip treatments. In addition, this
assessment evaluates whether these actions can be expected to result in modification of the species'
critical habitat. Key biological information for the CRLF is included in Section 2.5, and designated
critical habitat information for the species is provided in Section 2.6 of this assessment. This
ecological risk assessment has been prepared as part of the Center for Biological Diversity (CBD) vs.
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 endangered species assessment, direct and indirect effects to the CRLF and potential
modification to its critical habitat are evaluated in accordance with the methods (both base line and
species-specific refinements, when appropriate) described in the Agency's Overview Document
(U.S. EPA 2004). In addition, in accordance with two interim policies, terrestrial invertebrate LOCs
will be used and terrestrial amphibian modeling will used as a refinement. 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 mancozeb
and maneb is based on an action area. The action area is considered to be the area directly or
indirectly affected by the federal action, as indicated by the exceedances of Agency Levels of
Concern (LOCs) used to evaluate direct or indirect effects. It is acknowledged that the action area
for a national-level FIFRA regulatory decision associated with a use of mancozeb or maneb may
potentially involve numerous areas throughout the United States and its Territories. However, for
the purposes of this assessment, attention will be focused on relevant sections of the action area
including those geographic areas associated with locations of the CRLF and its designated critical
habitat within the state of California.
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As part of the "effects determination," one of the following three conclusions will be reached
regarding the potential for registration of mancozeb and maneb at the use sites described in this
document to affect CRLF individuals and/or result in modification of designated CRLF critical
habitat:
• "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
CRLFs are aquatic and upland areas where suitable breeding and non-breeding aquatic habitat is
located, interspersed with upland foraging and dispersal habitat (Section 2.6).
If the results of initial screening-level assessment methods show no direct or indirect effects (no
LOC exceedances) upon individual CRLFs or upon the PCEs of the species' designated critical
habitat, a "no effect" determination is made for the FIFRA regulatory action as it relates to this
species and its designated critical habitat. If, however, direct or indirect effects to individual CRLFs
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.
If a determination is made that use of mancozeb or maneb within the action area(s) associated with
the CRLF "may affect" this species 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 geographical proximity of CRLF habitat and mancozeb and maneb use sites) and
further evaluation of the potential impact of mancozeb and maneb 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 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 that 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 mancozeb and
maneb are expected to directly impact living organisms within the action area (defined in Section
2.7), critical habitat analysis for mancozeb and maneb 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 appreciably
diminish the value of the habitat. Evaluation of actions related to use of mancozeb and maneb 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 have been identified by the
Services and are discussed further in Section 2.6.
14
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2.2 Scope
Mancozeb and maneb are non-systematic preventive fungicides with wide use patterns including a
variety of row crops, orchards and vines, ornamentals, turf, and forestry in addition to seed or dip
treatment for seed and seed pieces. The total number of federally registered products applicable to
uses in CA is 55 for mancozeb and 25 for maneb. The California Department of Pesticide
Regulation (CDPR) registers pesticides for use within California as well. Of the 55 and 25
registered products for mancozeb and maneb respectively, California has registered only thirty-nine
mancozeb and eight maneb products2. However, that this assessment is based on the federal action
and therefore, considers the current federally registered labels. Instructions on these labels indicate
that mancozeb and maneb can be used interchangeably in about one third of the use patterns.
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 mancozeb and maneb in
accordance with the approved product labels for California is "the action" being assessed.
Although current registrations of mancozeb and maneb allow for nationwide use, this ecological risk
assessment and effects determination addresses currently registered uses of mancozeb and maneb in
portions of the action area that are reasonably assumed to be biologically relevant to the CRLF and
its designated critical habitat. Further discussion of the action area for the CRLF and its critical
habitat is provided in Section 2.7.
Mancozeb ((1,2-Ethanediylbis (carbamodithioato))(2-)) manganese and zinc mixture, and maneb,
(1,2-Ethanediylbis (carbamodithioato)(2-)-manganese, are members of the ethyl ene-A/.v-
dithiocarbamate group of fungicides (EBDCs). Parent mancozeb and parent maneb are both
expected to be hydrolytically unstable in the natural environment as both are applied under moist
conditions (rain and/or irrigation-fed growing plants). Therefore, this risk assessment is based on
estimates of exposure to the mancozeb and maneb hydrolytic residue; referred to hereinafter as the
EBDC complex. As it will be discussed later, the EBDC complex consists of multi-chemical species
including the major degradate ethylenethiourea (ETU). In the risk assessment process, acute
exposure concentrations will be estimated for chemical species present in the EBDC complex at the
short-term, which are believed to be the same chemical species causing the measured acute toxicity.
Likewise, chronic exposure concentrations will be estimated for ETU, the main constituent of the
aged EBDC complex, which is the same chemical from which the chronic toxicity is obtained. Use
of this procedure in the risk assessment process was necessary due to the unique hydrolytic
instability of mancozeb and maneb and the formation of the EBDC complex. Details of the short
and long-term exposure estimation procedures and justification for relating them to measured acute
and chronic effects are presented elsewhere in this document (2.10 Analysis Plan).
2 http://www.cdpr.ca.gov/cgi-bin/label/laba.pl7p chem=211&activeonlv=on
15
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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).
Mancozeb has twenty registered products that contain multiple active ingredients while maneb has
two. Analysis of the available open literature data and acute oral mammalian LD50 data for
multiple active ingredient products relative to the single active ingredient is provided in Appendix
A. The result of this analysis show that an assessment based on the toxicity of the single active
ingredient of maneb and of mancozeb (considering as well the EBDC complex and ETU
degradates) is appropriate.
The results of available toxicity data for mixtures of maneb and mancozeb with other pesticides are
presented in Sections 4.1.3, 4.2.4, Appendices A and D. The registrant has submitted several aquatic
and terrestrial plant studies conducted with mancozeb co-formulated products. The results of the
terrestrial plant studies conducted with mancozeb co-formulated products were used in this
assessment. No data is available on mancozeb as single active ingredient of Typical Enduse Product
(TEP).
Maneb and mancozeb have been linked to sub-lethal effects, of the thyroid (for example, thyroid
weight increases and microscopic changes in thyroid and lethargy). These potential sublethal effects
are discussed qualitatively in this assessment since it is not possible to quantitatively link effects
such as these to the selected assessment endpoints for the CRLF (i.e., survival, growth, and
reproduction of individuals and maintenance of critical habitat PCEs). Further detail on sub-lethal
effects of mancozeb and maneb is provided in Sections 4.1.1.4 and 4.2.1.3, for fish and birds,
respectively.
2.3 Previous Assessment
Mancozeb was first registered in the USA in 1948 while maneb was registered in 1962. Both
chemicals were registered as a broad-spectrum fungicide for use in agriculture, professional turf
management and horticulture. Degradation of these two EBDCs results in the formation of the
common metabolite ethylenethiourea (ETU). Between 1986 and 1995 the registration standards for
mancozeb and maneb were issued (1986-1987)/updated in 1992) and Special Reviews for EBDCs,
including mancozeb and maneb, were conducted requiring risk reduction measures, submission of
additional data, and cancellation of EBDC use on 11 food/feed crops. During this period, EPA
issued two data call-ins (DCIs) requiring data to complete re-registration (1986-1987) and to
evaluate worker exposure (October, 1995). In 2005, the Environmental Fate and Effects Division
(EFED) completed the environmental fate and ecological risk assessments, in support of the re-
registration eligibility decisions (REDs) on mancozeb, maneb, and their major common degradate
ETU (U.S. EPA, 2005a, b and c). Following this, OPP issued the REDs in three separate documents
16
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on mancozeb, maneb, and ETU in 20053. In these REDs, EPA determined that most uses of
mancozeb and maneb are eligible for re-registration provided specific risk mitigation measures are
adopted. These risk mitigation measures include: reduction of the application rates, limitation of the
number of applications per year and cancellation of some use patterns.
In the ecological risk assessment completed to support the RED for mancozeb, endangered species
chronic risk levels of concern (LOCs) were exceeded for birds, terrestrial-phase amphibians, reptiles
and mammals for all mancozeb uses. Also, acute and chronic risks to endangered species LOCs were
exceeded for freshwater fish, aquatic-phase amphibians and freshwater invertebrates for all modeled
uses of mancozeb. At that time, potential risk to terrestrial invertebrates was not assessed. Due to
lack of data, risks to terrestrial plants or vascular aquatic plants were not assessed. Based on data for
nonvascular plants, mancozeb's uses exceeded the endangered species acute risk LOC for
nonvascular aquatic plants.
In the ecological risk assessment completed to support the RED for maneb, endangered species
chronic risk LOCs were exceeded for birds, terrestrial-phase amphibians, reptiles and mammals for
all maneb uses. Also, the acute risk to endangered species LOC was exceeded for freshwater fish,
aquatic-phase amphibians and freshwater invertebrates for all maneb modeled uses. At that time
risk to terrestrial invertebrate was not assessed quantitatively. However, based on the lack of acute
maneb toxicity to honeybees, EFED expected a low acute risk to non-target terrestrial insects. Due
to lack of data, EFED did not assess chronic risks to freshwater invertebrates, terrestrial plants or
fully assess risks to aquatic plants. Based on data for one surrogate species, maneb's modeled use
patterns exceeded acute risk LOCs for nonvascular aquatic plants.
In the ecological risk assessment completed to support the RED for ETU, the chronic risk LOC was
exceeded for mammals across all uses of the parent compounds. Due to lack of data, potential acute
and chronic risks to birds, terrestrial-phase amphibians and reptiles, chronic risks to freshwater fish,
aquatic-phase amphibians and aquatic invertebrates, or potential acute risks to aquatic vascular
plants were not assessed.
2.4 Stressor Source and Distribution
In this assessment the stressor is considered to be the EBDC complex resulting from the rapid
hydrolysis of mancozeb and maneb in aquatic systems. For the terrestrial system, the stressor is
parent mancozeb and maneb and their major degradate ETU.
2.4.1 Environmental Fate and Transport Assessment
Mancozeb and maneb are polymers or highly coordinated salt complexes, in which each EBDC
ligand is present in coordination with zinc (Zn+2) and manganese (Mn+2) ions in mancozeb or with
manganese (Mn+2) ions alone in maneb. Table 2-1 specifies the identity of the two chemicals along
with a summary of laboratory measured physiochemical and abiotic fate properties (U.S. EPA, 2005
a, and b).
3 http://www.epa.gov/pesticides/reregistration/status.htm
17
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Table 2-1 Chemical identity and laboratory measured physiochemical and abiotic fate properties for
mancozeb and maneb.
Parameters
Mancozeb
Maneb
CAS name
((1,2-ethanediylbis (carbamodithioato)) (2-)
Mn mixture with ((1,2-ethandiylbis
(carbamodithioate)) (2-)) zinc
[[1,2-Ethanediylbis [carbamodithioato]] - (2-)]
manganese
CAS registry number
8018-01-7
12427-38-2
PC code
014504
014505
Molecular weight
271
265
Vapor pressure (torr)
1.003x10 -7
7.577 xlO -8
Water solubility*
6-20 ppm
150 ppm
Chemical structure
r ? s ~i
i ii
N C S
JZn+2]y
X
X:Y= 10:1
H S
1 II
ivr /-< c
u
[Mn2] —
N C S-"""
a
\
[Mi2]
/
»T t " C
_ II s _
Mancozeb
—T if
H S
Maneb
Hydrolysis
t Vi at pH 7= 0.7 day (17 hours)
t Vi at pH 7= <0.1 day (3 hours)
Aqueous & soil
photolysis
Stable
* Note that when mancozeb or maneb is dissolved in water up to 20 ppm of the polymeric mancozeb or 150 ppm of the
polymeric maneb completely hydrolyzes into the EBDC complex.
Based on laboratory fate studies, the complete polymeric chains of parent mancozeb or maneb (the
active ingredient "a.i" in mancozeb or maneb) are expected to be non-persistent in most natural
environments (hydrolysis t V2= <1 day). Hydrolytic decomposition appears to be a complex process
as it involves breakdown of the polymers into fresh EBDC complex consisting of variable/low
molecular weight polymeric chains (i.e. polymer fragments), monomelic species, transient species,
and EBDC ligand in association with metal ions other than Mn+2 or Zn+2. Aging of the complex
results in enrichment with ETU and ETU degradates. The rate of hydrolytic degradation appears to
increase with particle size reduction of the applied parent, availability of moisture, oxygen, and high
acidic and neutral conditions. The product of hydrolytic decomposition of mancozeb or maneb is a
multi-chemical species complex hereinafter referred to as the "mancozeb or maneb complex" or the
"EBDC complex".
In an agricultural setting, foliar application of mancozeb or maneb is expected to cause it to reach
plant/soil surfaces directly and air/water bodies by drift. In the air, either chemical will eventually
be deposited onto soil/plant/water surfaces with minimal change. On plant surfaces, it is affected by
physical wash-off and abiotic hydrolytic decomposition into the EBDC complex given water
availability and time. In contrast to each of the parents, the EBDC complex is a suite of multi-
chemicals. Based on fate studies and media of formation, the suite includes the following two
categories:
(a) Chemicals associated with the short-term acute exposure potential which includes variable/low
molecular weight polymeric chains and short-lived transient chemicals; and
(b) Chemicals associated with the long-term chronic exposure potential which includes ETU and
ETU degradates, and bound species.
18
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For the EBDC complex at the short-term, laboratory fate parameters were obtained using
radioactivity as a surrogate for concentration. Based on this radio-labeled fate data, it appears that
the fate of the complex is controlled by further hydrolytic decomposition, soil/sediment adsorption
and to a lesser extent biotic mineralization into CO2. Table 2-2 summarizes the fate parameters for
the EBDC complex of mancozeb and maneb calculated from parent studies (U.S. EPA, 2005c).
Table 2-2 Laboratory measured fate properties for the mancozeb and maneb complexes including
their major degradate, ETU.
Short-Term
Short-Term
Eate Parameter
constituents of the
Mancozeb Complex• *
constituents of the
Maneb Complex *
ETU
Hydrolysis t Vi at pH 7 (days)
4
Stable
Aqueous (direct) photolysis t Vi (days)
Stable
Photolysis on soil t Vi (days)
Stable
Aerobic soil metabolism t Vi (days)
21-29
8-12
1-3
Aerobic aquatic metabolism t
(days)
38-41
No study
No study
* Data are based on radiolabel associated the constituents of the EBDC complex minus ETU and ETU degradates.
For the aged EBDC complex (at the long-term), fate and transport data are available for only one of
its major constituents, ETU (Table 2-2, above). ETU data were obtained from studies in which ETU
was the experimental material. In contrast to ETU, bound residues forming in soil/sediment systems
were poorly characterized and there is uncertainty whether these residues are actually ethylene
diamine (EDA). However, in the absence of a complete characterization of the bound residues, the
screening-level assessments (U.S. EPA 2005a and b) included bound residues as part of the total
residue complex. Inclusion of bound residues in estimated half-lives resulted in conservative half-
life estimates for the total EBDC complex in soil and water/sediment systems. In this refined
assessment, exposure to bound species will be covered by ETU because bound species are suspected
to be precursor to ETU.
Fate properties of ETU were presented earlier in Table 2-2 and important physiochemical properties
are summarized in Table 2-3 (U.S. EPA 2005c).
Table 2-3 Chemical identity and laboratory measured physiochemical properties of ETU.
Parameters
ETU
Structure
CAS name
2-Imidazolidinethione
CAS Registry Number
96-45-7
NH
Xc=s
Molecular Weight
102
Vapor Pressure
9.728x10 -1
/
NH
Water Solubility
20,000 ppm
ETU
The constituents of the EBDC complex depend on the characteristics of the system and aging. For
example, bound residue is expected to form late and persist only in systems containing soil or
sediment particles. Furthermore, the important ETU metabolite was shown to vary in concentration
and persistence from one system to another (Table 2-4).
19
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Table 2-4 Maximum ETU produced in fate studies for parent EBDCs.
Parent EBDCs Used as a Test Substance i Maximum ETU Formed
Tvpe of Study
(Number of Studies)
.l.v "o Parent Equivalent
l.v ETU*
Aqueous Hydrolysis
Maneb (1); Metiram (1)
93.0%
35.8%
Aerobic/Anaerobic
Aquatic
Metiram (2); Maneb (1)
61.4%
23.6%
Aerobic Soil
Metiram (4); Mancozeb (3); Maneb (3)
24.8%
09.6%
* % ETU= % Parent Equivalent multiplied by Molar ratio of Parent to ETU of 38.5%; for example, the maximum for
hydrolysis studies= 93% x 0.385 = 35.8%.
Potential transport mechanisms include pesticide surface water runoff, spray drift, and secondary
drift of volatilized or soil bound residues leading to deposition onto nearby or more distant
ecosystems. A number of studies have documented atmospheric transport and re-deposition of
pesticides from the Central Valley to the Sierra Nevada Mountains (Fellers et al., 2004, Sparling et
al., 2001, LeNoir et al., 1999, and McConnell et al., 1998). Prevailing winds blow across the Central
Valley eastward to the Sierra Nevada Mountains, transporting airborne industrial and agricultural
pollutants into the Sierra Nevada ecosystems (Fellers et al., 2004, LeNoir el al., 1999, and
McConnell et al., 1998). Several sections of critical habitat for the CLRF are located east of the
Central Valley. The magnitude of transport via secondary drift depends on the maneb and
mancozeb's ability to be mobilized into air and its eventual removal through wet and dry deposition
of gases/particles and photochemical reactions in the atmosphere. Therefore, physicochemical
properties of these chemicals that describe its potential to enter the air from water or soil (e.g.,
Henry's Law constant and vapor pressure), pesticide use data, modeled estimated concentrations in
water and air, and available air monitoring data from the Central Valley and the Sierra Nevada's are
considered in evaluating the potential for atmospheric transport of mancozeb and maneb to locations
where it could impact the CRLF.
For mancozeb and maneb parents, the principal route of transport from application sites is expected
to be spray drift. Secondary drift (atmospheric transport) of volatilized parents leading to deposition
onto nearby or more distant ecosystems is not expected. This is attributed to the reported low vapor
pressures and Henry's law constants (1 x 10 7 torr and 5.5X10"9 atm. m3 mole"1 for mancozeb, and 8
x 10~8 and 9.97xl0"u atm. m3 mole"1 for maneb).
In general, deposition of drifting or volatilized pesticides is expected to be greatest close to the site
of application. Computer models of spray drift (AgDRIFT or AgDISP) are used to determine if the
exposures to aquatic and terrestrial organisms result in risk quotients that are below the Agency's
acute and chronic risk LOCs. If the maximum estimate environmental concentration (EEC)
determined using spray drift models (AgDrift and AgDISP) results in a risk quotient that is below
the LOC, then longer-range transport is not considered in defining the action area. For example, if a
buffer zone <1,000 feet (the optimal range for AgDRIFT and AgDISP models) results in terrestrial
and aquatic exposures that are below acute and chronic risk LOCs, no further drift analysis is
required. If exposures exceeding acute or chronic risk LOCs and buffers necessary to bring
exposure below the LOC are greater than 1,000 feet, the Gaussian extension feature of AgDISP may
be used.
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AgDRIFT (version 2.01) utilizes empirical data to estimate off-site deposition of aerial and ground
applied pesticides. Similarly, AgDISP (version 8.15) predicts the motion of spray material released
from aircraft, including the mean position of the material and the position variance about the mean
as a result of turbulent fluctuations.
In contrast to the movement of parent mancozeb and maneb by spray drift, run-off/erosion is the
principal route of transport for constituents of the EBDC complex from application sites to nearby
terrestrial and/or aquatic systems. This is due to rapid hydrolysis of parents and relative high affinity
of significant portions of the EBDC complex to soil particles.
Based on laboratory studies, the whole freshly formed EBDC complex, resulting from either
mancozeb or maneb, can be characterized by low mobility (FAO, 1998). Calculated Koc values were
in the range of 860-1,642 L kg-1 for the mancozeb complex and in the range of 400-1,692 L kg-1 for
the maneb complex. Aged EBDC complex of mancozeb and maneb is dominated by the ETU
degradate which is highly soluble (water solubility= 20,000 ppm) and very mobile (Average Koc=
288 L kg-1). In surface water, sources of ETU are formation from parent mancozeb or maneb
deposited by drift, transportation by runoff in dissolved form, and the possible continuous, slow
formation from bound species transported on soil particles by runoff or erosion. Quantities of ETU
that reach or form in natural surface water are expected to be stable to hydrolysis and direct
photolysis, however, it was reported that it can be removed rather quickly from these waters by
indirect photolysis (half-lives of 1-4 days). Additionally, the relatively short half-life of ETU in the
soil system (t V2 =1-3 days) reduces the possibility of leaching of this degradate to ground water.
2.4.2 Mechanism of Action
Mancozeb and maneb are broad-spectrum fungicides belonging to a chemical class of polymeric
dithiocarbamates and a group classified as ethylene-bis-dithiocarbamate (EBDC) fungicides. They
are non-systemic, contact fungicides with preventive activity. The EBDCs (mancozeb, maneb, and
metiram) can be metabolized to ETU which is of toxicological concern due to ETU's
carcinogenicity, teratogenicity, and anti-thyroid properties. OPP has determined that there is
sufficient evidence to group the EBDCs based on a common mechanism for the induction of thyroid
effects.
2.4.3 Use Characterization
Analysis of labeled use information is the critical first step in evaluating the federal action. The
current labels for mancozeb and maneb represent the FIFRA regulatory action; therefore, labeled
uses, application parameters (e.g., rates and methods), and restrictions specified on the labels 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
There are 55 and 25 agricultural labeled use patterns for mancozeb and maneb, respectively that are
relevant to California. In the REDs for mancozeb and maneb, EPA determined that most uses are
eligible for re-registration provided adoption of specific risk mitigation measures. Table 2-5 lists
measures that are expected to reduce environmental exposure from uses considered in this
assessment noting that implementation of these measures might take place sometime in 2009. It is
21
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however noted that some of the mitigation measures had already been implemented for all labels in
the case of papaya use pattern and some of the labels in the case of turf. Accordingly, in this
assessment, the new rate for papaya was used and no changes were considered in the case of turf.
This is because some of the available turf labels didn't include cancellation of residential and athletic
fields turf use pattern and reduction of rate to other turf uses including sod farms.
Table 2-5 Risk mitigation measures included in the mancozeb and maneb REDs4.
l/se Pattern
RED Risk Mitigation Measure
Mancozeb Use Patterns
Turf: residential and athletic fields
Use cancellation
Turf: others including sod farms
Reduce single rate from 19.1 to 17.4 lb a.i./A with a maximum of 4
applications or 69.6 lb a.i./year at a minimum of 10 to 14-day intervals
(increased from 5 to 7-day intervals).
Papaya1
Reduce single rate to 2 lb a.i./A (from 4 lb a.i./A) with a maximum of 14
applications or 28 lb a.i./year at a minimum of 14-day intervals 1
Sweet Corn
Homeowner use cancellation
Pachysandra (Ornamental plant)
Use cancellation
Pineapple
Seed piece treatment use cancellation
Cotton
Foliar use cancellation
Maneb Use Patterns
Sweet corn, grapes, apples, and kadota figs
Use cancellation
Rice and peanuts
Seed treatment use cancellation
Almonds
Reduce the maximum rate to 19.2 lb a.i./A/year (from 25.6 lb a.i./A/year)
with no change in the single rate of 6.4 lb a.i./A (three applications)
Turf: sod farm
Reduce single rate to 8.7 lb a,i./A with a maximum of 4 applications or
34.8 lb a.i./A/year (from 69.6 lb a.i./year)
Oats seed treatment
Reduce this single application rate to 0.21/cwt (0.211b a.i./A)
1 It appears that labels for this use pattern has affected this change in the single rate, therefore the new rate was used in
this risk assessment.
Application parameters relevant to the labeled use patterns included in Table 2-6 and Table 2-7 for
mancozeb, and Table 2-8 and Table 2-9 for maneb. These use patterns represent labeled uses up to
2007 and do not include mitigation measures stated in Table 2-5 above that have not been adopted
on product labels.
4 http://www.epa.gov/pesticides/reregistration/status.htm
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Table 2-6 Mancozeb use patterns in California (MSR= maximum single rate (lb a.i./acre), MNA=
maximum number of applications, MTR= maximum total rate (lb a.i./acre/crop cycle or year), and
MAI= minimum re-application intervals in days).
Crop Use Pattern
MSK
MNA
MTU '
MAI
Apples, Crab apple, Pear & Quince
4.8
4
19.2
1
Asparagus
1.6
4
6.4
10
Bananas
2.4
10
24
14
Cereal Grains2
1.6
3
4.8
7
Corn (field & seed)
1.2
10
12
4
Corn (sweet/pop)
1.2
5
6
4
Cotton
1.6
4
6.4
10
Cucurbits3
2.4
8
19.2
7
Fennel
1.6
8
12.8
7
Forestry (Douglas Fir)
3.2
3
9.6
14
Garlic & Onion: dried
2.4
10
24
7
Grapes
2.0
3
6.0
7
Ornamentals (pachysandra)
17.4
5
87.1
10
Ornamentals (others)4
1.4
5
6.8
7
Papayas
2
14
28
14
Plantains
2.4
10
24
14
Potatoes
1.6
7
11.2
3
Shallot
2.4
10
24
7
Sugar Beet
1.6
7
11.2
7
Tomatoes
1.6
4
6.4
7
Turf 5
19.1
4
76.4
5
X-mass tree plantations
3.2
3
9.6
14
1 MTR= maximum total rate in lb a.i./acre/year is only for apples, crab apple, pear & quince otherwise this rate is in lb
a.i./acre/crop cycle.
2 Grains include: barley, oats, rye, triticale, and wheat.
3
Cucurbits: cucumber, cantaloupe, honey dew, casaba melon, crenshaw melon, watermelon, musk melon and edible
gourds
4 Ornamentals (others) include: shade trees, ground cover plants, herbaceous plants, non-flowering plants & woody
shrubs and vines.
5 Turf includes: commercial/industrial/recreational area lawns, golf course turf, ornamental sod farm turf, and ornamental
lawns & turf (residential).
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Table 2-7 Additional mancozeb use patterns in California: Dip and pre-plant seed treatments
(Maximum application rate; all are single rates)
I. Dip or Seedling Treatment (as specified below): Rates in lbs/Acre
Use Pattern
Rate (lb ill/Acre)
Asparagus: pre-plant crowns dip in burlap bag or dip tank
3.0
Capri fig: dip treatment in a dip tank
3.2
Potatoes: pre-plant seed/seed pieces dip tank @ 0.08 cwt1
2.72 (seedling rate of 3,400 lbs/Acre)5
Pineapple: pre-plant dip treatment
25.6
II. Pre-plant Seed Treatment (Mist, Slurry and Planter/Drill boxes)
Use Pattern
Application Kate (cwt')
Seeding Rate (lb/Acre)'1
Application Rate (lb a.i/Acre)
Barely
0.2100
100
0.2100
Corn
0.2719
18.3
0.0498
Cotton
0.3156
10
0.0316
Flax
0.3602
50
0.1801
Oats
0.3150
100
0.3150
Rice
0.2094
150
0.3141
Rye
0.1801
90
0.1621
Safflower
0.1063
25
0.0266
Sorghum
0.2271
12
0.0273
Tomatoes
0.3984
0.5
0.0020
Triticale
0.1650
90
0.1485
Wheat
0.1625
89
0.1446
1 cwt= hundredweight (i.e., lbs/100 lbs of seeds).
5 Potatoes: http://qardenquide.montana.edu/additional%20info%20paqes/Veqetable%20Charts.htm
http://www.hort.purdue.edu/newcrop/duke energy/A vena sativa.html#Cultivation
6 Barley: http://www.aq.ndsu.edu/procrop/bar/baseed04.htm
Corn, cotton, rice and wheat: http://www.hort.purdue.edu/newcrop/duke energy/
Flax, rye, safflower sorghum: http://www.hort.purdue.edu/newcrop/afcm/flax.html
Oats: http://extension.oregonstate.edu/catalog/html/em/em8692/
Tomatoes: http://aggie-horticulture.tamu.edu/extension/vegetable/cropguides/tomato.html
Triticali: http://southeastfarmpress.com/news/90204Triticale-cover/
Other Reference: http://www.reimerseeds.com/Search.aspx?Kevword=Triticali
24
-------
Table 2-8 Maneb use patterns in California (MSR= maximum single rate (lb a.i./acre), MNA=
maximum number of applications, MTR= maximum total rate (lb a.i./acre/crop cycle or year), and
MAI= minimum re-application intervals in days).
Crop Use Pattern
MSR
MNA
MTR1
MAI
Almonds
6.4
4
25.6
1
Apples
4.8
4
19.2
1
Bananas
2.4
10
24
14
Beans (dried)
1.6
6
9.6
5
Brassica2
1.6
6
9.6
7
Brussels sprouts
1.6
6
9.6
7
Corn (sweet/pop)
1.2
5
6
3
Chinese Cabbage "loose head"
1.2
6
7.2
7
Cucurbits3
1.6
8
12.8
7
Eggplant
1.6
7
11.2
7
Figs
One application of 2.4 lb a.i/acre/season
Garlic & Onion: dried
2.4
10
24
7
Grapes
2
3
6
7
Kale
1.6
2
3.2
7
Lettuce (leaf & head) and Endive (Escarole)
1.6
6
9.6
7
Onion: green
2.4
7
16.8
7
Ornamentals (pachysandra)
13.9
4
55.7
10
Ornamentals (others)4
1.2
3
3.6
7
Papayas
2
14
28
14
Pepper
1.6
6
9.6
7
Potatoes
1.6
7
11.2
5
Sugar Beet
1.6
7
11.2
7
Tomatoes
1.6
4
6.4
7
Turf5
17.4
4
69.7
7
1 MTR= maximum total rate in lb a.i./acre/year is for apples only otherwise this rate is in lb a.i./acre/crop cycle.
2 Brassica: broccoli, Brussels sprouts, cabbage, Chinese cabbage (tight head), cauliflower, and kohlrabi.
3
Cucurbits: cucumber, cantaloupe, honeydew, casaba melon, crenshaw melon, watermelon, winter squash, and
pumpkin.
4 Ornamentals (others) include: shade trees, ground cover plants, herbaceous plants, non-flowering plants & woody
shrubs and vines.
5 Turf includes: commercial/industrial/recreational area lawns, golf course turf, ornamental sod farm turf, and ornamental
lawns & turf (residential).
25
-------
Table 2-9 Additional maneb use patterns in California: dip and pre-plant seed treatments (maximum
application rate; all are single rates).
I. Dip Treatment (as speeified below): Rates in lbs/Acre
Use Pattern
Rate (lb a.i./Acre)
Potatoes: pre-plant seed/seed pieces dip lank (m 0.08 cwl'
2.72 (seedling rale of 3.400 lbs/Acre)
II. Pre-plant Seed Treatment (Mist, Slurry
and Planter/Drill boxes)
Use Pattern
Application Kate (cwr')
Seeding Rare (lb/Acre)''
Application Kate (lb a.i/Acre)
Barely
0.2094
100
0.2094
Corn
0.2688
18.3
0.0492
Cotton
0.3
10
0.0300
Flax
0.3531
50
0.1766
Oats
0.3125
100
0.3125
Rice
0.20
150
0.3000
Rye
0.1781
90
0.1603
Safflower
0.1
25
0.0250
Sorghum
0.225
12
0.0270
Tomatoes
0.4
0.5
0.0020
Wheat
0.1625
89
0.1446
1 cwt= hundredweight (i.e., lbs/100 lbs of seeds).
Mancozeb and maneb labeled use data can be summarized into three types of applications: 1) foliar,
2) dip and 3) seed treatments. Equipment that can be used include: aerial equipment, ground-boom,
chemigation, high- and low-pressure handheld equipment, and backpack sprayers. Important
information for foliar applications can be summarized as follows:
(a) Use patterns for mancozeb and maneb may be categorized for into five categories:
1) Row, field and vegetable crops;
2) Orchards and vines;
3) Nursery and greenhouse;
4) Turf; and
5) Forestry.
7 Potatoes: http://qardenquide.montana.edu/additional%20info%20paqes/Veqetable%20Charts.htm
http://www.hort.purdue.edu/newcrop/duke energy/A vena sativa.html#Cultivation
8 Barley: http://www.aq.ndsu.edu/procrop/bar/baseed04.htm
Corn, cotton, rice and wheat: http://www.hort.purdue.edu/newcrop/duke energy/
Flax, rye, safflower sorghum: http://www.hort.purdue.edu/newcrop/afcm/flax.html
Oats: http://extension.oregonstate.edu/catalog/html/em/em8692/
Tomatoes: http://aggie-horticulture.tamu.edu/extension/vegetable/cropguides/tomato.html
26
-------
(b) Use patterns either are for mancozeb alone, maneb alone, or interchanged between mancozeb
and maneb. Mancozeb alone uses include crops belonging to categories 1, 2, and 3; maneb alone
uses include crops belonging to categories 1, 2, and 6; while mancozeb and maneb uses include
crops belonging to all categories except 6. Later in section 2.7, a separation between labeled
uses for mancozeb, maneb, and mancozeb & maneb are included.
(c) The maximum single application rates are: pome fruits/forestry (4.8/3.2 lb a.i./A) for mancozeb;
almonds/apples (6.4/4.8 lb a.i./A) for maneb; and turf/pachysandra for mancozeb & maneb
(mancozeb rates=19.1/13.9 lb a.i./A and maneb rates= 17.4/13.9 lb a.i./A). Single rates for
mancozeb and maneb use on all other crops are in the range of 1.2 to 3.2 lb a.i./A.
(d) The ranges of seasonal application rates are cereal grains/onions & garlic (4.8 to 24.0 lb
~.i./A/season) for mancozeb; figs/almonds (2.4 to 25.6 lb a.i./A/season) for maneb; and grapes &
corn/turf for mancozeb & maneb (mancozeb rates=6.0 to 76.4 lb a.i./A/season and maneb rates=
~.0 to 69.7 lb a.i./A/season)
(e) Number of applications range from one to 15 (mostly 3 to 10) with application intervals ranging
from 7 to 14 days (mostly 3 tolO days).
(f) With the exception of residential landscaping (ornamentals & turf), all types of ground and aerial
applications are permitted. Turf and ornamentals, in residential areas, are treated by ground
spray.
(g) Several crops can be grown more than one time per year in CA (i.e., they have multiple crop
cycles). Labels specified seasonal application rates on the labels except of mancozeb use on
pome fruits (yearly rates were specified). Therefore, for uses that have more than one crop cycle
per year, the maximum allowable yearly application rate will be higher than the maximum
seasonal application rate. Multiple cropping is discussed later in the assessment (refer to section
3.2.2 modeling inputs).
For seed and seed pieces treatments, the application methods for treatment include commercial
stationary equipment, on-farm stationary equipment and tractor drawn planter boxes. Important
information can be summarized as follows:
(a) Mancozeb and maneb are used as a seed treatment for only 8 crops that can also be treated
later with foliar sprays. These crops lie within the field crops and vegetables category. The
list of crops is: four cereal grains "except triticale" with application rates ranging from 0.15-
0.32 lb a.i. /A for either mancozeb or maneb; cotton and corn with application rates ranging
from 0.03-0.05 lb a.i./A for either mancozeb or maneb (maneb is not foliar applied to cotton);
and tomatoes with an application rate of 0.002 lb a.i./A for either mancozeb or maneb.
Triticale seeds can only be treated with mancozeb with a rate of 0.15 lb a.i./A.
(b) Mancozeb and maneb can also be used to treat seeds alone for an additional four crops,
namely: flax, safflower, sorghum, and rice with application rates ranging from 0.03-0.31 lb
a.i. /A.
(c) Seeds and dip treatments are one-time treatments and multiple cropping is not reported for
any of the crops for which the seeds are treated.
(d) Mancozeb and maneb are used as a pre-plant for potato seed or seed piece as a dip treatment
with the same application rate of 2.72 lb a.i./seed or seed pieces needed for one acre.
27
-------
Additionally, dip treatment is used on asparagus, Capri fig and pineapple, which are treated
with mancozeb only with rates ranging from 3.2 to 25.6 lb a.i/A. Due to the fact that the dip
solution is used only to treat plant parts, quantities of pesticide active expected to reach
seeded soils are minimal.
Of all federally labeled uses of mancozeb and maneb, peanuts and cranberry and tobacco use
patterns were excluded from our assessment. This is because, peanuts and cranberry are grown in
very limited acreage in California and tobacco is not grown in California.
EPA's Biological and Economic Analysis Division (BEAD) provides an analysis of both national -
and county-level usage information (Kaul and Jones, 2006) using state-level usage data obtained
from USDA-NASS9, Doane (www.doane.com. the full set is not provided due to its proprietary
nature), and the CDPR, Pesticide Use Reporting (PUR) database10. CDPR PUR is considered a
more comprehensive source of usage data than USDA-NASS or EPA proprietary databases, and thus
the usage data reported for mancozeb and maneb by county in this CA-specific assessment were
generated using CDPR PUR data. Four years (2002-2005) of usage data were included in this
analysis. Data from CDPR PUR were obtained for every pesticide application made on every use
site at the section level (approximately one square mile) of the public land survey system. BEAD
summarized these data to the county level by site, pesticide, and unit treated. Calculating county-
level usage involved summarizing across all applications made within a section and then across all
sections within a county for each use site and for each pesticide. The county level usage data that
were calculated include: average annual pounds applied, average annual area treated, and average
and maximum application rate across all five years. The units of area treated are also provided
where available. A summary of these data is presented inTable 2-10 and Table 2-11 for mancozeb
and maneb, respectively.
9 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.
10 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.
28
-------
Table 2-10 California usage data for mancozeb
Use Pattern
Average Annual Applied Across 2002-2005
Application Rate Across All
observations
Lbs. Used
Area Treated
Lbs
0/
/o
Acres
0/
/o
A verage
Maximum
ONION, DRY
62,707
12.97%
36,716
14.27%
1.8
4.4
TURF/SOD
61,721
12.77%
5,772
2.24%
8.2
33.8
TOMATO, PROCESSING
58,638
12.13%
47,729
18.55%
1.3
3.4
POTATO
58,597
12.12%
48,123
18.71%
1.1
4.1
GRAPE
57,209
11.84%
40,120
15.60%
1.4
4.8
LANDSCAPE MAINTENANCE
51,628
10.68%
ND*
ND
ND
ND
GRAPE, WINE
48,835
10.10%
34,080
13.25%
1.4
8.3
PEAR
30,767
6.37%
10,597
4.12%
2.9
7
N-OUTDR TRANSPLANTS
26,228
5.43%
21,931
8.52%
1.2
7.5
APPLE
18,517
3.83%
7,568
2.94%
2.6
8.9
WHEAT (FORAGE - FODDER)
3,276
0.68%
2,007
0.78%
1.7
3.1
FENNEL
1,380
0.29%
929
0.36%
1.3
1.5
SUGARBEET
1,379
0.29%
956
0.37%
1.5
1.5
GARLIC
396
0.08%
192
0.07%
2.1
2.3
ONION, GREEN
382
0.08%
253
0.10%
1.5
1.7
STRAWBERRY
105
0.02%
35
0.01%
2
2.3
ASPARAGUS
99
0.02%
87
0.03%
1.1
1.5
WATERMELON
90
0.02%
49
0.02%
1.7
2.4
CUCUMBER
32
0.01%
14
0.01%
2.3
3.4
CHRISTMAS TREE
25
0.01%
10
0.00%
2.8
3.1
OTHERS**
1,291
0.26%
90
0.05%
ND-1.3
ND-2.3
TOTALS
483,302
100%
257,258
100%
* ND= Not determined; ** Others= research commodity, right of way, soil fumigation/pre-plant, structural pest control
and vertebrates control. These are not registered uses of mancozeb and there report may be attributed to misreporting,
misuse, or data entry error.
29
-------
In addition, Figure 2-1 summarizes the distribution of the crop use patterns for mancozeb while
those for the counties are included in Appendix B.
Mancozeb Use: Distribution of 257,258 treated acres (483,302 lbs used)
ALL OTHERS
18%
GRAPES
29%
TURF/SOD
2%
ONION, DRY
14%
POTATO
19%
TOMATO
18%
Figure 2-1 Important crop use patterns for mancozeb
30
-------
Table 2-11 California usage data for maneb
Use Pattern
I verage Annual Applied Across 2002-2005
Application Rate Across All
observations
Lbs. Used
Area Treated
Lbs
0/
/o
Acres
0/
/o
Average
Maximum
LETTUCE, LEAF
513,598
52.13%
373,234
58.82%
1.3
5.5
WALNUT
248,608
25.23%
145,595
22.95%
1.7
5.7
ALMOND
108,733
11.04%
35,472
5.59%
3.2
9.5
ONION, DRY
31,110
3.16%
19,172
3.02%
1.7
3.2
TOMATO, PROCESSING
28,303
2.87%
25,434
4.01%
1.1
3.3
POTATO
10,006
1.02%
8,790
1.39%
1.2
4.8
TURF/SOD
7,721
0.78%
555
0.09%
17.4
82.4
BROCCOLI
6,549
0.66%
4,881
0.77%
1.3
4.5
N-OUTDR TRANSPLANTS
6,281
0.64%
3,170
0.50%
1.3
5.3
CABBAGE
4,902
0.50%
3,833
0.60%
1.3
3.6
ONION, GREEN
4,429
0.45%
2,815
0.44%
1.7
5.5
CHINESE CABBAGE (NAPPA)
4,398
0.45%
3,493
0.55%
1.2
1.9
GRAPE
2,022
0.21%
1,516
0.24%
1.7
4.3
CAULIFLOWER
1,779
0.18%
1,245
0.20%
1.4
5
PEPPER, FRUITING
1,650
0.17%
1,377
0.22%
1.1
2.4
GRAPE, WINE
1,265
0.13%
610
0.10%
2.1
6.3
BOK CHOY
1,224
0.12%
1,148
0.18%
1.1
2.2
BRUSSELS SPROUT
994.7
0.10%
776.8
0.12%
1.4
1.6
SPINACH*
521
0.05%
337
0.05%
1.2
4.9
ENDIVE (ESCAROLE)
381
0.04%
275
0.04%
1.4
3.8
SUGARBEET
209.6
0.02%
180.5
0.03%
1.2
1.2
SQUASH, SUMMER
153.7
0.02%
103.2
0.02%
1.2
1.4
CELERY
108
0.01%
54
0.01%
2.1
5.1
APPLE
101
0.01%
42
0.01%
None
100.8
BEAN, UNSPECIFIED
70.1
0.01%
47.8
0.01%
1.4
1.5
CORN, HUMAN
CONSUMPTION
66.3
0.01%
53.8
0.01%
1.2
1.5
GARLIC
50
0.01%
233
0.04%
0.5
2
KOHLRABI
30
0.00%
28
0.00%
1.3
3
WATERMELON
17
0.00%
12
0.00%
1.5
1.6
CUCUMBER
16
0.00%
11
0.00%
1.3
1.6
PUMPKIN
12
0.00%
9
0.00%
None
12.2
COLLARD*
2.5
0.00%
2.3
0.00%
1.1
1.2
985,311
100.00%
634,505
100.00%
* Spinach and collards are not registered uses for maneb and there report may be attributed to misreporting, misuse, or
data entry error.
31
-------
In addition, Figure 2-2 summarizes the distribution of the crop use patterns for mancozeb while
those for the counties are included in Appendix B.
Maneb use in CA: Distribution of 634,505 acres treated (985,311 lbs used)
ALL OTHERS
3%
TOMATOES
4%
ONION
3%
ALMONDS & WALNUTS
28%
COLE CROPS
2%
LETTUCE
60%
Figure 2-2 Important crop use patterns for maneb
Analysis of the 2002-2005 CDPR PUR usage data is important in determining the intensity and
extent of mancozeb and maneb usage in California. For intensity of use, reported mancozeb and
maneb application rates, across all use reported, show average rates that are generally consistent with
or less than the maximum allowable label rates. However, it appears that there are some problems in
the reported maximum rates, as it appears to be generally higher than labeled maximum rates. Data
on the average four-year annual amounts of applied mancozeb (a total of 483,302 lbs) suggest that
nearly 99% of this amount is distributed between the top ten uses as follows: grapes (22%); onions
(13%), turf/sod (13%); tomatoes (12%); potatoes (12%); landscaping (11%); pears (6%); nursery
plants (5%); apples (4%); and wheat (1%). In terms of extent of use, the same crops also represent
99% of total acreage treated (257,258 Acres) but with different order of % treated as follows: grapes
(29%); potatoes (19%); tomatoes (19%); onions (14%); nursery plants (9%); pears (4%); apples
(3%); turf/sod (2%) and wheat (1%); with no acreage reported for landscaping.
In contrast, the average annual amounts of maneb (985,311 lbs) for the same four years was much
higher than mancozeb with nearly 99% of this amount distributed between the top ten uses as
follows: lettuce (52%); walnuts (25%), almonds (11%); onion (4%); tomatoes (3%); cole crops
(2%); and potatoes, turf/sod/nursery and dried beans (4% total, 1% each). The same crops also
represent 99% of total acreage treated (634,506 Acres) with the % treated as follows: lettuce (59%);
walnuts (23%), almonds (6%); onion (3%); tomatoes (4%); cole crops (2%); and potatoes,
turf/sod/nursery and dried beans (4% total, 1% each).
32
-------
In general, data revealed that of the total amounts of the two EBDCs used was mancozeb and that
this quantity of mancozeb was used to treat nearly ]A (29%) of the total area treated. Almost 98% of
the total quantity of the two EBDCs was used to treat 15 use patterns, which represents nearly 98%
of the total treated acreage. Table 2.12 summarizes the distribution of the total quantity of
mancozeb/maneb between various use patterns as well as the distribution of the total acreage treated
in the state of California.
Table 2-12 Combined usage data for mancozeb and maneb showing the % share for each
Mancozeb Share: % *
Maneb Share: "» *
Use Pattern
Pounds
Acres
Pounds
Acres
Lettuce
35%
42%
Walnuts and Almonds
No reported usage
24%
20%
Cole Crops
1%
2%
Grapes, including Wine
7%
8%
No reported usage
Tomato, Processing
4%
5%
2%
3%
Onion, Dry
4%
4%
2%
2%
Potatoes
4%
5%
1%
1%
Turf: Sod
4%
1%
1%
0%
Residential Landscaping
4%
ND
Pear and Apples
3%
2%
No reported usage
Nursery: Outdoor plants & Wheat
2%
2%
Totals
32%
28%
66%
70%
Pounds Applied (32%+66%= 98%)
32%
-
66%
-
Acres Treated (28%+70%= 98%)
-
28%
-
70%
* % of the total pounds of a.i used of mancozeb or maneb from the total pound used for both or % of the total acres
treated by mancozeb or maneb from the total acres treated by both EBDCs.
Figure 2-3 is included to display the spatial distribution of total use of mancozeb and maneb and the
relative use between the two chemicals in all the counties of California. In this Figure, large blue
circles represent total use of maneb + mancozeb while the inner red circles represent mancozeb use
only. For reference, recovery units and all catchments associated with CRLF are included.
33
-------
Siskiyou,,..
; Mencfoein
4 *
Countv
1= Butt*
:= .¦¦jlu-,5
:•= iui-i
4= sUtt«l
5= if.-lo
"= 5 ¦¦ 1-1:llll-rhto
7= i 111 J do I
3= Conr) C^'T)
':= -Oil I'- 1'|llll'l
10= 'it ,1 111 JI .HI',
ii = r.UH<.~i
I ;= ¦; 111 B-?lllt"?
N
A
I" *
II *
IJ
9
220
Santa Barbara
uu
Ln.:- Angeles
San Bernardino
~
Riverside
SanDieao
* •
Mancozeb (Mz) -
Mz+Maiieb (000's lbs)
0-1
0-1
Recovery Zones
# 1-7
#
1-7
i Central Coast
# 7-14
•
7-14
. Diablo Range / Salinas Valley
• 14-28
©
14-28
North Coast foothills and Western Sacramento River
• 2®-54
o
28-54
: North San Francisco Bay/North Coast
54-69
54-69
jrn Transverse Range and Techachapi Mountains
Sierra Nevada foothills
•
•
89-359
and East San Francisco Bay
: Southern Transverse Range and Peninsular ranges
Catchm ents Associated with CRLF
Figure 2-3 Mancozeb and maneb reported usage data in relation to CRLF (county level
data/average of five years).
34
-------
Finally, 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. Historical uses are not
considered part of the federal action and, therefore, are not considered in this assessment.
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). A brief summary of information regarding CRLF distribution,
reproduction, diet, and habitat requirements is provided in Sections 2.5.1 through 2.5.4, respectively.
Further information on the status, distribution, and life history of and specific threats to the CRLF is
provided in Attachment 1.
Final critical habitat for the CRLF was designated by USFWS on April 13, 2006 (USFWS 2006; 71
FR 19244-19346). Further information on designated critical habitat for the CRLF is provided in
Section 2.6.
2.5.1 Distribution
The CRLF is endemic to CA and Baja California (Mexico) and historically inhabited 46 counties in
CA including the Central Valley and both coastal and interior mountain ranges (USFWS 1996). Its
range has been reduced by about 70%, and the species currently resides in 22 counties in CA
(USFWS 1996). 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 CRLF populations have been
documented below 1,050 meters (3,500 feet) (USFWS 2002).
Populations currently exist along the northern CA coast, northern Transverse Ranges (USFWS
2002), foothills of the Sierra Nevada (5-6 populations), and in southern CA south of Santa Barbara
(two populations) (Fellers 2005a). Relatively larger numbers of CRLFs are located between Marin
and Santa Barbara Counties (Jennings and Hayes 1994). 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 CRLFs (i.e., streams, creeks, tributaries, associated natural and artificial
ponds, and adjacent drainages), and habitats through which CRLFs can move (i.e., riparian
vegetation, uplands) (USFWS 2002).
The distribution of CRLFs within CA is addressed in this assessment using four categories of
location including recovery units, core areas, designated critical habitat, and known occurrences of
the CRLF reported in the California Natural Diversity Database (CNDDB) that are not included
within core areas and/or designated critical habitat (see Figure 2.a). Recovery units, core areas, and
other known occurrences of the CRLF from the CNDDB are described in further detail in this
section, and designated critical habitat is addressed in Section 2.6. 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
35
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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.
2.5.1.1 Recovery Units
Eight recovery units have been established by USFWS for the CRLF. These areas are considered
essential to the recovery of the species, and 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 statuses, and therefore, similar
recovery goals. The eight units described for the CRLF 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. The eight recovery units for the CRLF are listed in Table 2-13
and shown in Figure 2-4.
Table 2-13 CRLF Recovery Units with Overlapping Core Areas and Designated Critical F
abitat
Recovery Unit'
(Figure 3)
Core Areas " (Figure 3)
Critical Habitat Units
Currently Occupied
(post-1 985) 4
Historically
Occupied4
Sierra Nevada
Foothills and
Central Valley
(1)
(eastern
boundary is the
1,500m
elevation line)
Feather River (1)
BUT-1A-B
•/
Yuba River-S. Fork Feather River (2)
YUB-1
--
NEV-1
Traverse Creek/Middle Fork American
River/Rubicon (3)
--
Consumnes River (4)
ELD-1
S. Fork Calaveras River (5)
--
y
Tuolumne River (6)
--
s
Piney Creek (7)
--
s
East San Francisco Bay (partial)(16)
--
North Coast
Range Foothills
and Western
Sacramento
River Valley (2)
Cottonwood Creek (8)
--
Putah Creek-Cache Creek (9)
--
y
North Coast and
North San
Francisco Bay
(3)
Putah Creek-Cache Creek (partial) (9)
--
y
Lake Berryessa Tributaries (10)
NAP-1
Upper Sonoma Creek (11)
--
Petaluma Creek-Sonoma Creek (12)
--
Pt. Reyes Peninsula (13)
MRN-1, MRN-2
Belvedere Lagoon (14)
--
Jameson Canyon-Lower Napa River (15)
SOL-1
South and East
San Francisco
Bay (4)
--
CCS-1A
East San Francisco Bay (partial) (16)
ALA-1A, ALA-IB,
STC-1B
--
STC-1A
South San Francisco Bay (partial) (18)
SNM-1A
Central Coast (5)
South San Francisco Bay (partial) (18)
SNM-1A, SNM-2C,
SCZ-1
36
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Recovery Unit'
(Figure 3)
Core Areas (Figure 3)
Critical Habitat Units 3
Currently Occupied
(l>ost-1985) 4
Historically
Occupied4
Watsonville Slough- Elkhorn Slough
(partial) (19)
SCZ-2 5, MNT-15
S
Carmel River-Santa Lucia (20)
MNT-2
S
Estero Bay (22)
--
S
Arroyo Grande Creek (23)
SLO-8
S
Santa Maria River -Santa Ynez River
(24)
--
S
Diablo Range
and Salinas
Valley (6)
East San Francisco Bay (partial) (16)
MER-1A-B
S
--
SNB-1, SBB-2
S6
Santa Clara Valley (17)
--
Watsonville Slough- Elkhorn Slough
(partial)(19)
--
Carmel River-Santa Lucia (partial) (20)
--
Gablan Range (21)
SNB-3
Estrella River (28)
SLO-1
Northern
Transverse
Ranges and
Tehachapi
Mountains (7)
--
SLO-8
Santa Maria River-Santa Ynez River
(24)
STB-4, STB-5,
STB-7
Sisquoc River (25)
STB-1, STB-3
Ventura River-Santa Clara River (26)
VEN-1, VEN-2,
VEN-3
--
LOS-1
¦/ 6
Southern
Transverse and
Peninsular
Ranges (8)
Santa Monica Bay-Ventura Coastal
Streams (27)
--
San Gabriel Mountain (29)
--
•/
Forks of the Mojave (30)
--
Santa Ana Mountain (31)
--
Santa Rosa Plateau (32)
--
San Luis Rey (33)
--
•/
Sweetwater (34)
--
Laguna Mountain (35)
--
Recovery units designated by the USFWS (USFWS 2000, pg 49)
2 Core areas designated by the USFWS (USFWS 2000, pg 51)
3 Critical habitat units designated by the USFWS on April 13, 2006 (USFWS 2006, 71 FR 19244-19346)
4 Currently occupied (post-1985) and historically occupied core areas as designated by the USFWS (USFWS 2002, pg 54)
5 Critical habitat unit where identified threats specifically included pesticides or agricultural runoff (USFWS
6 Critical habitat units that are outside of core areas, but within recovery units
7 Currently occupied core areas that are included in this effects determination are bolded.
37
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180 Miles
Legend
] Recovery Unit Boundaries
Currently Occupied Core Areas
| Critical Habitat
| CNDDB Occurence Sections
County Boundaries o
Recovery Units
1. Sierra Nevada Foothills and Central Valley
2. North Coast Range Foothills and Western
Sacramento River Valley
3. North Coast and North San Francisco Bay
4. South and East San Francisco Bay
5. Central Coast
6. Diablo Range and Salinas Valley
7. Northern Transverse Ranges and Tehachapi
Mountains
8. Southern Transverse and Peninsular Ranges
Core Areas
1. Feather River
19.
Watsonville Slough-Elkhorn Slough
2. Yuba River- S. Fork Feather River
20.
Carmel River - Santa Lucia
3. Traverse Creek/ Middle Fork/ American R. Rubicon
21.
Gablan Range
4. Cosumnes River
22.
Estero Bay
5. South Fork Calaveras River*
23.
Arroyo Grange River
6. Tuolumne River*
24.
Santa Maria River - Santa Ynez River
7. Piney Creek*
25.
Sisquoc River
8. Cottonwood Creek
26.
Ventura River - Santa Clara River
9. Putah Creek - Cache Creek*
27.
Santa Monica Bay - Venura Coastal Streams
10. Lake Berryessa Tributaries
28.
Estrella River
11. Upper Sonoma Creek
29.
San Gabriel Mountain*
12. Petaluma Creek - Sonoma Creek
30.
Forks of the Mojave*
13. Pt. Reyes Peninsula
31.
Santa Ana Mountain*
14. Belvedere Lagoon
32.
Santa Rosa Plateau
15. Jameson Canyon — Lower Napa River
33.
San Luis Ray*
16. East San Francisco Bay
34.
Sweetwater*
17. Santa Clara Valley
35.
Laguna Mountain*
18. South San Francisco Bay
* Core areas that were historically occupied by the California red-legged frog are not included in the map
Figure 2-4 Recovery unit, core area, critical habitat, and occurrence designations for CRLF
38
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2.5.1.2 Core Areas
USFWS has designated 35 core areas across the eight recovery units to focus their recovery efforts
for the CRLF (Figure 2-4). The core areas, which are distributed throughout portions of the historic
and current range of the species, represent areas that allow for long-term viability of existing
populations and reestablishment of populations within 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.
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. Each type
of locational information is evaluated within the broader context of recovery units. For example, if
no labeled uses of mancozeb or Maneb occur (or if labeled uses occur at predicted exposures less
than the Agency's LOCs) within an entire recovery unit, a "no effect" determination would be made
for all designated critical habitat, currently occupied core areas, and other known CNDDB
occurrences within that recovery unit. Historically occupied sections of the core areas are not
evaluated as part of this assessment because the USFWS Recovery Plan (USFWS 2002) indicates
that CRLFs are extirpated from these areas. A summary of currently and historically occupied core
areas is provided in Table 2-13 (currently occupied core areas are bolded). While core areas are
considered essential for recovery of the CRLF, core areas are not federally designated critical
habitat, although designated critical habitat is generally contained within these core recovery areas.
It should be noted, however, that several critical habitat units are located outside of the core areas,
but within the recovery units. The focus of this assessment is currently occupied core areas,
designated critical habitat, and other known CNDDB CRLF occurrences within the recovery units.
Federally designated critical habitat for the CRLF is further explained in Section 2.6.
2.5.1.3 Other Known Occurrences from the CNDBB
The CNDDB provides location and natural history information on species found in California. The
CNDDB serves as a repository for historical and current species location sightings. Information
regarding known occurrences of CRLFs outside of the currently occupied core areas and designated
critical habitat is considered in defining the current range of the CRLF. See: for additional
information on the CNDDB, refer to the web site stated below11.
2.5.2 Reproduction
CRLFs breed primarily in ponds; however, they may also breed in quiescent streams, marshes, and
lagoons (Fellers 2005a). According to the Recovery Plan (USFWS 2002), CRLFs breed from
November through late April. Peaks in spawning activity vary geographically; Fellers (2005b)
reports peak spawning as early as January in parts of coastal central CA. Eggs are fertilized as they
are being laid. Egg masses are typically attached to emergent vegetation, such as bulrushes (Scirpus
spp.) and cattails (Typha spp.) or roots and twigs, and float on or near the surface of the water
11 http://www.dfg.ca.gov/bdb/html/cnddb info.html
39
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(Hayes and Miyamoto 1984). Egg masses contain approximately 2000 to 6000 eggs ranging in size
between 2 and 2.8 mm (Jennings and Hayes 1994). Embryos hatch 10 to 14 days after fertilization
(Fellers 2005a) depending on water temperature. Egg predation is reported to be infrequent and
most mortality is associated with the larval stage (particularly through predation by fish); however,
predation on eggs by newts has also been reported (Rathburn 1998). Tadpoles require 11 to 28
weeks to metamorphose into juveniles (terrestrial-phase), typically between May and September
(Jennings and Hayes 1994, USFWS 2002); tadpoles have been observed to over-winter (delay
metamorphosis until the following year) (Fellers 2005b, USFWS 2002). Males reach sexual
maturity at 2 years, and females reach sexual maturity at 3 years of age; adults have been reported to
live 8 to 10 years (USFWS 2002). Figure 2-5 depicts CRLF annual reproductive timing.
J
F
M
A
M
J
J
A
S
o
N
D
Light Blue =
Green = Tadpoles (except those that over-winter)
Orange = Young Juveniles
Adults and juveniles can be present all year
Figure 2-5 CRLF Reproductive Events by Month
2.5.3 Diet
Although the diet of CRLF aquatic-phase larvae (tadpoles) has not been studied specifically, it is
assumed that their diet is similar to that of other frog species, with the aquatic phase feeding
exclusively in water and consuming diatoms, algae, and detritus (USFWS 2002). Tadpoles filter and
entrap suspended algae (Seale and Beckvar, 1980) via mouthparts designed for effective grazing of
periphyton (Wassersug, 1984, Kupferberg et al.; 1994; Kupferberg, 1997; Altig and McDiarmid,
1999).
Juvenile and adult CRLFs forage in aquatic and terrestrial habitats, and their diet differs greatly from
that of larvae. The main food source for juvenile aquatic- and terrestrial-phase CRLFs is thought to
be aquatic and terrestrial invertebrates found along the shoreline and on the water surface. Hayes and
Tennant (1985) report based on a study examining the gut content of 35 juvenile and adult CRLFs,
that the species feeds on as many as 42 different invertebrate taxa, including Arachnida, Amphipoda,
Isopoda, Insecta, and Mollusca. The most commonly observed prey species were larval alderflies
(Sialis cf. californica), pillbugs (Armadilliadrium vulgare), and water striders (Gerris sp). The
preferred prey species, however, was the sowbug (Hayes and Tennant, 1985). This study suggests
that CRLFs forage primarily above water, although the authors note other data reporting that adults
also feed under water, are cannibalistic, and consume fish. For larger CRLFs, over 50% of the prey
mass may consists of vertebrates such as mice, frogs, and fish, although aquatic and terrestrial
invertebrates were the most numerous food items (Hayes and Tennant 1985). For adults, feeding
activity takes place primarily at night; for juveniles feeding occurs during the day and at night
(Hayes and Tennant 1985).
40
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2.5.4 Habitat
CRLFs require aquatic habitat for breeding, but also use other habitat types including riparian and
upland areas throughout their life cycle. CRLF use of their environment varies; they may complete
their entire life cycle in a particular habitat or they may utilize multiple habitat types. Overall,
populations are most likely to exist where multiple breeding areas are embedded within varying
habitats used for dispersal (USFWS 2002). Generally, CRLFs utilize habitat with perennial or near-
perennial water (Jennings et al. 1997), dense vegetation close to water, shading, and water of
moderate depth are habitat features that appear especially important for CRLF (Hayes and Jennings
1988).
Breeding sites include streams, deep pools, backwaters within streams and creeks, ponds, marshes,
sag ponds (land depressions between fault zones that have filled with water), dune ponds, and
lagoons. Breeding adults have been found near deep (0.7 m) still or slow moving water surrounded
by dense vegetation (USFWS 2002); however, the largest number of tadpoles have been found in
shallower pools (0.26 - 0.5 m) (Reis, 1999). Data indicate that CRLFs do not frequently inhabit
vernal pools, as conditions in these habitats generally are not suitable (Hayes and Jennings 1988).
CRLFs also frequently breed in artificial impoundments such as stock ponds, although additional
research is needed to identify habitat requirements within artificial ponds (USFWS 2002). Adult
CRLFs use dense, shrubby or emergent vegetation closely associated with deep-water pools
bordered with cattails and dense stands of overhanging vegetation
(http://www.fws.gov/endangered/features/rl frog/rlfrog.html#where).
In general, dispersal and habitat use depends on climatic conditions, habitat suitability, and life
stage. Adults rely on riparian vegetation for resting, feeding, and dispersal. The foraging quality of
the riparian habitat depends on moisture, composition of the plant community, and presence of pools
and backwater aquatic areas for breeding. CRLFs can be found living within streams at distances up
to 3 km (2 miles) from their breeding site and have been found up to 30 m (100 feet) from water in
dense riparian vegetation for up to 77 days (USFWS 2002).
During dry periods, the CRLF is rarely found far from water, although it will sometimes disperse
from its breeding habitat to forage and seek other suitable habitat under downed trees or logs,
industrial debris, and agricultural features (UWFWS 2002). According to Jennings and Hayes
(1994), CRLFs also use small mammal burrows and moist leaf litter as habitat. In addition, CRLFs
may also use large cracks in the bottom of dried ponds as refugia; these cracks may provide moisture
for individuals avoiding predation and solar exposure (Alvarez 2000).
2.6 Designated Critical Habitat
In a final rule published on April 13, 2006, 34 separate units of critical habitat were designated for
the CRLF by USFWS (USFWS 2006; FR 51 19244-19346). A summary of the 34 critical habitat
units relative to USFWS-designated recovery units and core areas was previously discussed in
Section 2.5.1, above.
41
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'Critical habitat' is defined in the ESA as the geographic area occupied by the species at the time of
the listing where the physical and biological features necessary for the conservation of the species
exist, and there is a need for special management to protect the listed species. It may also include
areas outside the occupied area at the time of listing if such areas are 'essential to the conservation of
the species.' All designated critical habitat for the CRLF was occupied at the time of listing.
Critical habitat receives protection under Section 7 of the ESA through prohibition against
destruction or adverse modification with regard to actions carried out, funded, or authorized by a
federal Agency. Section 7 requires consultation on federal actions that are likely to result in the
destruction or adverse modification of critical habitat.
To be included in a critical habitat designation, the habitat must be 'essential to the conservation of
the species. Critical habitat designations identify, to the extent known using the best scientific and
commercial data available, habitat areas that provide essential life cycle needs of the species or areas
that contain certain 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. The designated critical habitat areas for the CRLF are considered to have
the following PCEs that justify critical habitat designation:
• Breeding aquatic habitat;
• Non-breeding aquatic habitat;
• Upland habitat; and
• Dispersal habitat.
Please note that a more complete description of these habitat types is provided in Attachment 1.
Occupied habitat may be included in the critical habitat only if essential features within the habitat
may require special management or protection. Therefore, USFWS does not include areas where
existing management is sufficient to conserve the species. Critical habitat is designated outside the
geographic area presently occupied by the species only when a designation limited to its present
range would be inadequate to ensure the conservation of the species. For the CRLF, all designated
critical habitat units contain all four of the PCEs, and were occupied by the CRLF at the time of FR
listing notice in April 2006. The FR notice designating critical habitat for the CRLF 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. Please see Attachment 1 for a full explanation on this
special rule.
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. Evaluation of actions related to use of
Mancozeb and maneb that may alter the PCEs of the CRLF's critical habitat form the basis of the
critical habitat impact analysis. According to USFWS (2006), activities that may affect critical
42
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habitat and therefore result in adverse effects to the CRLF include, but are not limited to the
following:
(1) Significant alteration of water chemistry or temperature to levels beyond the tolerances of the
CRLF that result in direct or cumulative adverse effects to individuals and their life cycles.
(2) Significant increase in sediment deposition within the stream channel or pond or disturbance of
upland foraging and dispersal habitat that could result in elimination or reduction of habitat
necessary for the growth and reproduction of the CRLF by increasing the sediment deposition to
levels that would adversely affect their ability to complete their life cycles.
(3) Significant alteration of channel/pond morphology or geometry that may lead to changes to the
hydrologic functioning of the stream or pond and alter the timing, duration, water flows, and
levels that would degrade or eliminate the CRLF and/or its habitat. Such an effect could also
lead to increased sedimentation and degradation in water quality to levels that are beyond the
CRLF's tolerances.
(4) Elimination of upland foraging and/or aestivating habitat or dispersal habitat.
(5) Introduction, spread, or augmentation of non-native aquatic species in stream segments or ponds
used by the CRLF.
(6) Alteration or elimination of the CRLF's food sources or prey base (also evaluated as indirect
effects to the CRLF).
As previously noted in Section 2.1, the Agency believes that 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 mancozeb and maneb are expected to directly impact living organisms
within the action area, critical habitat analysis for mancozeb and maneb are limited in a practical
sense to those PCEs of critical habitat that are biological or that can be reasonably linked to
biologically mediated processes.
2.7 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 mancozeb and
maneb is likely to encompass considerable portions of the United States based on the large array of
uses for the two chemicals. 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 products under consideration and the types of effects that mancozeb and maneb
may be expected to have on the environment, the exposure levels to mancozeb and maneb that are
associated with those effects, and the best available information concerning the use of the two
chemicals and their fate and transport within the state of California.
43
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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 mancozeb and maneb.
An analysis of labeled uses and review of available product labels was completed. This analysis
indicates that, for mancozeb and maneb, the following uses are considered as part of the federal
action evaluated in this assessment:
(1) Foliar application of either mancozeb alone, maneb alone, or interchanged between maneb and
mancozeb. Uses are summarized in Table 2-14.
Table 2-14 Summary of use patterns for mancozeb and maneb alone and maneb and mancozeb
together
Mancozeb Use Only
Maneb Use Only
Mancozeb or Maneb
1. Row, field and vegetable crops
Asparagus
Beans (Dried)
Corn (Sweet/Pop) (1-3 crops/year)
Cereal Grains (1)
Brassica (1-3 crop/year)(2)
Cucurbits (3)
Corn (Field & seed crop)
Brussels sprouts (1-2 crops/year)
Garlic
Cotton
Cabbage (Chinese)/Loose (1-3 crops/year)
Onion (Dried)
Fennel (1-2 crops)
Eggplant
Potatoes
Shallot
Kale (1-3 crops/year)
Sugar Beet
X-mass tree plantations
Lettuce. and Endive (1-2 crops/vcar)
Tomatoes
-
Onion (Green) (1-2 crops/vcar)
Ornamentals
-
Pepper
-
2. Orchards & Vincvards
Crab apple, pear, and quince
Almonds
Apples
Plantains
Figs
Bananas
-
Walnuts
Grapes
-
Grapes (Wine)
-
Papavas
3. Residential Landscaping
_
_
Ornamentals (Others)111
-
-
Ornamentals (Pachvsandra)
-
-
Ornamentals (lurO
4. Turf
-
-
Turf (sod farms) (1-2 crops/vcar)
-
-
Turf (5)
5. Forestrv
Forestry (Douglas Fir)
-
-
(1) Cereal grains include: wheat, barley, oats, rye, and triticale.
(2) Brassica include broccoli, cabbage and Chinese cabbage (tight head), cauliflower, and Kohlrabi
(3) Cucurbits: Mancozeb use only: muskmelon and gourds; Maneb only: squash (winter) and pumpkins; both: cantaloupe,
honeydew, casaba, Crenshaw and winter melons.
(4) Ornamentals include shade trees, ground cover plants, herbaceous plants, non-flowering plants and woody plants,
shrubs and vines.
(5) Turf includes commercial/industrial/recreational area lawns, golf course turf, and ornamental sod farm turf.
(2) Seed treatment with mancozeb or maneb interchangeably on eight crops that are also treated with
foliar sprays later in the season. The crops are: cereal grains, except triticale; cotton; corn; and
tomatoes. Triticale seeds can only be treated with mancozeb. Seed treatment alone (with no foliar
treatment) is labeled for an additional four crops, namely: flax, safflower, sorghum, and rice.
44
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(3) Pre-plant potatoes seed/seed pieces dip treatment with either mancozeb or maneb; and
(4) Dip treatment use for asparagus, Capri fig and pineapple using mancozeb only.
After a determination of which uses will be assessed, an evaluation of the locations of potential use
sites that will be assessed is determined. The potential use sites represent the initial area of concern
or "footprint" which is typically based on available land cover data. Local land cover data available
for the state of California were analyzed to refine the understanding of potential mancozeb and
maneb use. The initial area of concern is defined as all land cover types that represent the labeled
uses of mancozeb and maneb in the state of California. Therefore, a map representing all the land
cover types that make up the initial area of concern is presented in Figure 2-6 for mancozeb alone
use patterns, Figure 2-7 for maneb only use patterns, and Figure 2-8 for the interchangeable use of
mancozeb and maneb.
45
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Mancozeb Initial Area of Concern
;,-v.
Legend
| All Uses of Mancozeb
Initial Streams Effected by Mancozeb
~ County boundaries
Kilometers
W580 60 90 120
Compiled from California County boundaries (ESRI, 2002),
US DA National Agriculture Statistical Service (NASS, 2002)
Gap Anal/sis Program Orchard/Vineyard Landcover (GAP)
National Land Cover Database (NLCD) (MRLC, 2001)
Map created by US Environmental Protection Agency, Office
of Pesticides Programs, Environmental Fate and Effects Division.
September, 2007. Projection: Albers Equal Area Conic USGS,
North American Datum of 1983 (NAD 1983)
Figure 2-6 Initial area of concern for the use of mancozeb alone
46
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Maneb Initial Area of Concern
Legend
| maneb Ag Orch Habitat ovlp
maneb Agriculture - Orchard
CNDDB occurence sections
| Criti cal_h abitat
Core areas
County boundaries
Recovery Units
¦ Kilometers
0 225 50 75 100
Compiled from California County boundaries (ESRI, 2002),
USDA National Agriculture Statistical Setvice (NASS, 2002)
Gap Analysis Program Orchard/Vineyard Landcover (GAP)
National Land Cover Database (NLCD) (MRLC, 2001)
Map created by US Environmental Protection Agency, Office
of Pesticides Programs, Environmental Fate and Effects Division-
September, 2007. Projection: Albers Equal Area Conic USGS,
North American Datum of 1983 (NAD 1983)
Figure 2-7 Initial area of concern for the use of maneb alone
47
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Maneb and Mancozeb Initial Area of Concern
Legend
mancozeb&maneb ag use
mancozeb&maneb orchard use
mancozeb&maneb turf use
CNDDB_occurrence_sections
| Criticaljiabitat
Core areas
i County boundaries
^ " > A
¦ '#
Kilometers
D1530 60 90 120
Compiled from California County boundaries (ESRI, 2002),
USDA National Agriculture Statistical Service (NASS, 2002)
Gap Analysis Program Orchard/Vineyard Landcover (GAP)
National Land Cover Database (NLCD) (MRLC, 2001)
Map created by US Environmental Protection Agency, Office
of Pesticides Programs, Environmental Fate and Effects Division-
October, 2007. Projection: Albers Equal Area Conic USGS,
North American Datum of 1983 (NAD 1983)
Figure 2-8 Initial area of concern for the interchangeable use of mancozeb or maneb
48
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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 mancozeb and maneb to determine which routes of transport are likely to have an impact on the
CRLF. The exposure routes for mancozeb and maneb most likely to affect non-target organisms are
spray drift and runoff. To determine the action area for this assessment, the terrestrial and aquatic
portions of the action area in California are determined separately and then are combined to produce
a final action area. GIS maps for the final action area are included in Appendix C for mancozeb
use, Appendix I for maneb use, and Appendix L for the combined mancozeb and maneb use.
2.8 Assessment of Endpoints and Measures of Ecological Effect
Assessment endpoints are defined as "explicit expressions of the actual environmental value that is
to be protected"12. 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., waterbodies, riparian vegetation, and upland and dispersal
habitats), the migration pathways of mancozeb and maneb (e.g., runoff, spray drift, etc.), and the
routes by which ecological receptors are exposed to mancozeb and maneb-related contamination
(e.g., direct contact, etc).
2.8.1 Assessment Endpoints for the CRLF
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 or habitat
modification. 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
mancozeb and maneb is providedin Table 2-15.
12FromU.S. EPA (1992). Framework for Ecological Risk Assessment. EPA/630/R-92/001.
49
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Table 2-15 Summary of assessment endpoints and measures of ecological effects for direct and
indirect effects of mancozeb/maneb on the CRLF
Assessment Endpoint
Measures of Ecological Effects 1
Aquatic Phase (eggs, larvae, tadpoles, juveniles, and adults) aanc*c
1. Survival, growth, and reproduction of
CRLF individuals via direct effects on
aquatic phases
la. Most sensitive fish or amphibian acute LC50
Mancozeb -Rainbow trout {Oncorhynchus mykiss)
LC50 460 ppb, Maneb-O. mykiss LC50 42ppb
lb. Most sensitive fish or amphibian chronic ETU
(chronic exposure) - freshwater fish NOAEC
37.32ppm (estimated ACR)
lc Most sensitive fish or amphibian early-life stage
data (No guideline data available for ETU).
2. Survival, growth, and reproduction of
CRLF individuals via effects to food
supply {i.e., freshwater invertebrates, non-
vascular plants)
2a. Most sensitive fish, aquatic invertebrate, and
aquatic plant EC50 or LCsoMancozeb-Daphnid magna
LC50 580 ppb Maneb D. magna -LC50 = 120 ppb
-Mancozeb- 0. mykiss LC50 = 460 ppb Maneb-(9.
mykiss LC50 42ppb
Mancozeb Pseudokirchneriella subcaptitatum
(formerly Selenastrum Psedokirchneriella) EC so = 47
ppb Maneb P. subcaptitatum EC so =13.4 ppb
2b. Most sensitive aquatic invertebrate and fish
chronic NOAEC (No early lifestage fish data
available for ETU) D. magna NOAEC = 2.0 ppm
3. Survival, growth, and reproduction of
CRLF individuals via indirect effects on
habitat, cover, and/or primary productivity
{i.e., aquatic plant community)
3a. Vascular plant acute EC50 (No data available for
mancozeb or maneb
3b. Non-vascular plant acute ECsMancozeb
freshwater green algae (P. subcavtitatum) EC™ = 47
DDb; Maneb P. subcavtitatum EC50 =13.4 Dob.
4. Survival, growth, and reproduction of
CRLF individuals via effects to riparian
vegetation, required maintaining acceptable
water quality and habitat in ponds and
streams comprising the species' current
range.
4a. Distribution of EC25 values for monocots -No
data available on Mancozeb as single active
ingredient of TEP. No data available for Maneb
4b. Distribution of EC25 values for dicots - No data
available on mancozeb as single active ingredient of
TEP. No data available for Maneb
Terrestrial Phase (Juveniles and adults) b and c
5. Survival, growth, and reproduction of
CRLF individuals via direct effects on
terrestrial phase adults and juveniles
5a.) Most sensitive bird or terrestrial-phase
amphibian acute LC50 or LD5Mancozeb-Enufish
sparrow {Passer domesticus) acute oral LD50 ~ 1,500
mg/kgb Maneb -Northern bobwhite quail {Colinus
virginianus) acute oral LD50 >2, 150 mg/kgb
Maneb -Mallard duck {Anasplatyrhynchos)
Subacute dietary LC50 = >5,000 ppm
5b. Most sensitive bird or terrestrial-phase
amphibian chronic NOAEC: Mancozeb A.
50
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Assessment Endpoint
Measures of Ecological Effects 1
platyrhynchos reproduction NOAEC = 125 ppm
Maneb, Anas platyrhynchos reproduction NOAEC 20
ppm
6. Survival, growth, and reproduction of
CRLF individuals via effects on prey {i.e.,
terrestrial invertebrates, small terrestrial
vertebrates, including mammals and
terrestrial phase amphibians)
6a. Most sensitive terrestrial invertebrate and
vertebrate acute EC50 or LC50 -Mancozeb-Honey bee
{(Apis mellifra) 1396.2 ppm, Maneb - Apis mellifra
acute contact- LD50= > 12.09, Mancozeb predatory
mite {Typhlodromuspyri) Residual toxicity LR50a =
0.0lib a.i./A
-Mancozeb Rattus norvegicus acute oral LD50
>5,000 mg/kg Maneb- R. norvegicus LD50 >5,000
mg/kg
6b. Most sensitive terrestrial invertebrate and
vertebrate chronic NOAEC Mancozeb Rattus
norvegicus reproductive NOAEL =120 ppm Maneb
R norvegicus reproductive NOAEC =75ppm,
7. Survival, growth, and reproduction of
CRLF individuals via indirect effects on
habitat {i.e., riparian vegetation)
7a. Distribution of EC25 for monocots -No data
available on Mancozeb as single active ingredient of
TEP Maneb - no data available
7b. Distribution of EC25 for dicots -No data available
on Mancozeb as single active ingredient of TEP.
Maneb - no data available
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.
c Although the most sensitive toxicity value is initially used to evaluate potential indirect effects,
sensitivity distribution is used (if sufficient data are available) to evaluate the potential impact to
food items of the CRLF.
1 All registrant-submitted and open literature toxicity data reviewed for this assessment is included in Appendix D and
H.
2.8.2 Assessment Endpoints for Designated Critical Habitat
As previously discussed, designated critical habitat is assessed to evaluate actions related to the use
of mancozeb and maneb that may alter the PCEs of the CRLF's critical habitat. PCEs for the CRLF
were previously described in Section 2.6. Actions that may destroy or adversely modify critical
habitat are those that alter the PCEs. Therefore, these actions are identified as assessment endpoints.
It should be noted that evaluation of PCEs as assessment endpoints is limited to those of a biological
nature (i.e., the biological resource requirements for the listed species associated with the critical
habitat) and those for which mancozeb and maneb effects data are available.
Assessment endpoints and measures of ecological effect selected to characterize potential
modification to designated critical habitat associated with exposure to mancozeb and maneb are
51
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provided in Table 2-16. Adverse modification to the critical habitat of the CRLF includes the
following, as specified by USFWS (2006) and previously discussed in Section 2.6:
(1) Alteration of water chemistry/quality including temperature, turbidity, and oxygen content
necessary for normal growth and viability of juvenile and adult CRLFs.
(2) Alteration of chemical characteristics necessary for normal growth and viability of juvenile and
adult CRLFs.
(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.
Measures of such possible effects by labeled uses of mancozeb and maneb on critical habitat of the
CRLF are described in Table 2-16. 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. Assessment endpoints used for the
analysis of designated critical habitat are based on the adverse modification standard established by
USFWS (2006).
Table 2-16 Summary of assessment endpoints and measures of ecological effect for primary
constituent elements of the CRLF designated critical habitat
Assessment Endpoint
Measures of Ecological Effect'
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 CRLFs.
a. Most sensitive aquatic plant ECsoMancozeb -
P. subcaptitatum EC50 = 47 Dob; maneb P.
subcaptitatum EC50 = 13.4 ppb,
b. Distribution of EC25 values for terrestrial
monocots -No data available on mancozeb as
single active ingredient of TEP Maneb - no data
available
c. Distribution of EC25 values for terrestrial
dicots-No data available on mancozeb as single
active ingredient of TEP. Mancozeb - no data
available
Alteration in water chemistry/quality including
temperature, turbidity, and oxygen content
necessary for normal growth and viability of
juvenile and adult CRLFs and their food source 2
a. Most sensitive EC50 values for aquatic plant-
Mancozeb - P. subcaptitatum EC50 = 47 ppb,
maneb P. subcaptitatum EC50 =13.4 oob,
b. Distribution of EC25 values for terrestrial
monocots -No data available on mancozeb as
single active ingredient of TEP Maneb, no data
available
c. Distribution of EC25 values for terrestrial
dicots -No data available on mancozeb as single
52
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Assessment Endpoint
Measures of Ecological Effect'
active ingredient of TEP. Maneb- no data
available
Alteration of other chemical characteristics
necessary for normal growth and viability of
CRLFs and their food source.
a. Mancozeb 0. mykiss LC50 = 460 ppb ;
maneb-O. mykiss LC50 42ppb
Mancozeb- D. magna EC50 580 ppb; maneb D.
magna - LC50 = 120 ppb
b. ETU - freshwater fish NOAEC 37.32ppm
(estimated ACR)
ETU D. magna NOAEC =2.0ppm
Reduction and/or modification of aquatic-based
food sources for pre-metamorphs (e.g., algae)
a. Most sensitive aquatic plant ECsoMancozeb PL
subcaptitatum EC so = 47 ppb; maneb P.
subcavtitatum EC so =13.4 Dob,
Terrestrial Phase PCEs (Upland Habitat and Dispersal Habitat)
Elimination and/or disturbance of upland habitat;
ability of habitat to support food source of
CRLFs: Upland areas within 200 ft of the edge
of the riparian vegetation or dripline surrounding
aquatic and riparian habitat that are comprised of
grasslands, woodlands, and/or wetland/riparian
plant species that provides the CRLF shelter,
forage, and predator avoidance
a. Distribution of EC25 values for monocots -No
data available on Mancozeb as single active
ingredient of TEP
b. Distribution of EC25 values for dicots No data
available on Mancozeb as single active
ingredient of TEP
c. Lab rat acute oral: mancozeb and maneb LD50
>5000 = >5,000 mg/kg. Maneb- R. norvegicus
LD50 >5,000 mg/kg
. Rattus norvegicus Mancozeb reproductive
NOAEL =120 ppm Maneb reproductive
NOAEC =75ppm,
d. Honey bee acute contact Mancozeb LD5=
1396.2 ppm, Maneb - LD5= > 12.09, Mancozeb
predatory mite (Typhlodromuspyri) Residual
toxicity LR50a = 0.011b a.i./A
e. English sparrow (P.domesticusj Mancozeb
acute oral LD50 ~ 1,500 mg/kg, Northern
bobwhite quail Maneb acute oral LD50 >2, 150
mg/kgb Mallard duck Maneb Subacute dietary
LC50 = >5,000 ppm ; Mallard duck reproduction
Mancozeb NOAEC =125 ppmb ,Maneb
NOAEC= 20 ppm
f. Rainbow trout Mancozeb LC50 460 ppb,
Maneb- LC50 42ppb; chronic freshwater fish
ETU NOAEC 37.32ppm (estimated ACR)
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
Reduction and/or modification of food sources
for terrestrial phase juveniles and adults
Alteration of chemical characteristics necessary
for normal growth and viability of juvenile and
adult CRLFs and their food source.
1 All toxicity data reviewed for this assessment are included in Appendix D & H.
2 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.
53
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2.9 Conceptual Model
2.9.1 Risk Hypothesis
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 mancozeb and maneb to the environment. The following risk hypotheses
are presumed for this endangered species assessment:
• Labeled uses of mancozeb and maneb within the action area may directly affect the CRLF by
causing mortality or by adversely affecting growth or fecundity;
• Labeled uses of mancozeb and maneb within the action area may indirectly affect the CRLF
by reducing or changing the composition of food supply;
• Labeled uses of mancozeb and maneb within the action area may indirectly affect the CRLF
and/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 mancozeb and maneb within the action area may indirectly affect the CRLF
and/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 mancozeb and maneb 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 mancozeb and maneb 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 CRLFs;
• Labeled uses of mancozeb and maneb 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 mancozeb and maneb 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 mancozeb and maneb 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 CRLFs.
2.9.2 Diagram
The conceptual model is a graphic representation of the structure of the risk assessment. It specifies
the stressor release mechanisms, biological receptor types, and effects endpoints of potential
concern. The conceptual models for aquatic and terrestrial phases of the CRLF are shown in Figure
2-9 and Figure 2-10, and the conceptual models for the aquatic and terrestrial PCE components of
critical habitat are shown in Figure 2-1 land Figure 2-12. Exposure routes shown in dashed lines are
54
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not quantitatively considered because the resulting exposures are expected to be so low as not to
cause adverse effects to the CRLF.
Stressor
Source
Exposure
Media
Receptors
Attribute
Change
Long range
atmospheric
transport
| Runoff
¦~i Groundwater
Spray drift
Wet/dry deposition
Uptake/gills
or integument
Uptake/cell,
roots, leaves
Uptake/gills
or integument
Ingestion
Inaestion
s 1
Aquatic Animals
Invertebrates
Vertebrates
Aquatic Plants
Non-vascular
Vascular
Food chain
Reduction in algae
Reduction in prey
Red-legged Frog
Eggs Juveniles
Larvae Adult
Tadpoles
Riparian plant
terrestrial
exposure
pathways see
Figure 2-10
Surface water/
Sediment
Individual organisms
Reduced survival
Reduced growth
Reduced reproduction
Habitat integrity
Reduction in primary productivity
Reduced cover
Community change
Resultant EBDC complex and ETU from rapid hydrolysis of applied
Mancozeb and Maneb use site
Figure 2-9 Conceptual model for pesticide effects on aquatic phase of the CRLF
55
-------
Stressor
Source
Exposure
Media
Resultant EBDC complex and ETU from rapid hydrolysis of applied
Mancozeb and Maneb use site
Direct
Application
Ingestion
Amphibians |->
Terrestrial
Insects
Spray drift
-Dermal uptake/lngestion-
II Runoff I
1
Terrestrial/riparian plants |*
Grasses/forbs, fruit, seeds
(trees, shrubs)
Root uptake
Soil
T7
.Y.
Long range
atmospheric
transport
¦Wet/dry deposition-"
-~Ingestion
Ingestion
Ingestion
L* L
Ingestion
iMammals
i
Receptors
Red-legged Frog
Juvenile
Adult
Attribute
Change
Individual organisms
Reduced survival
Reduced growth
Reduced reproduction
Food chain
Reduction in prey
Habitat integrity
Reduction in primary productivity
Reduced cover
Community change
Figure 2-10 Conceptual model for pesticide effects on terrestrial phase of the CRLF
56
-------
Stressor
~i Groundwater j
Long range
atmospheric
transport
| Spray drift |
Source
Runoff
Exposure
Media
Wet/dry depositions
Uptake/gills or
integument
Uptake/cell,
roots, leaves
Uptake/gills or
integument
Receptors
Ingestion
Ingestion
Community
Reduced seedling
emergence or
vegetative vigor
Population
Yield
Reduced yield
Attribute
Change
Habitat
PCEs
Aquatic Animals
Invertebrates
Vertebrates
Aquatic Plants
Non-vascular
Vascular
Surface water/
Sediment
Food sources
Reduction in algae
Reduction in prey
Red-legged Frog
Eggs Juveniles
Larvae Adult
Tadpoles
Population
Reduced survival
Reduced growth
Reduce reproduction
Individual organisms
Reduced survival
Reduced growth
Reduced reproduction
Other chemical
characteristics
Adversely modified
chemical characteristics
Riparian and
Upland plants
terrestrial exposure
pathways & PCEs
see Figure 2-12
Resultant EBDC complex and ETU from rapid hydrolysis of applied
Mancozeb and Maneb use site
Habitat quality and channel/pond
morphology or geometry
Adverse water quality changes
Increased sedimentation
Reduced shelter
Figure 2-11 Conceptual model for pesticide effects on aquatic components of the CRLF critical
habitat
57
-------
Stressor
Source
Exposure
Media and
Receptors
Resultant EBDC complex and ETU from rapid hydrolysis of applied
Mancozeb and Maneb use site
Direct
Application
i
Terrestrial
Insects
Spray drift
1
I
Runoff
~~r~
¦ Dermal uptake/lngestion^— Soil
.T.
Long range
atmospheric
transport
Terrestrial plants
Grasses/forbs, fruit,
seeds (trees, shrubs)
Ingesljon
-Root uDtake T j
Wet/dry deposition^.-
-~Inaestion
Red-legged
Frog:
Juvenile & Adult
Attribute Individual organisms
Change Reduced survival
Reduced growth
Reduced reproduction
Habitat Other cfcimical
PCEs characteristics
Adversely modified
chemical characteristics
Ingestions-
Ingestion
I I
Mammals
_r t_
Population
Reduced survival
Reduced growth
Reduced reproducion
Community
Reduced seedling emergence
or vegetative vigor
(Distribution)
I
Food resources
Reduction in food
sources
Elimination and/or disturbance of
upland or dispersal habitat
Reduction in primary productivity
Reduced shelter
Restrict movement
Figure 2-12 Conceptual model for pesticide effects on terrestrial components of the CRLF critical
habitat
58
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2.10 Analysis Plan
The analysis plan is the final step in Problem Formulation. During this step, measurements of effect
and exposure used to evaluate the risk hypotheses are delineated, and uncertainties and assumptions
required to address them are identified. The Analysis Plan provides a synopsis of measures that will
be used to evaluate the risk hypotheses. There are three categories of measures: exposure, effects,
and risk. This risk assessment represents a unique case because it covers two active ingredients and
it is based on a modified procedure to accommodate the multi-chemical constituents of the assigned
stressor, the EBDC complex.
First, the risk assessment of mancozeb and maneb was combined for two reasons:
• Many uses can be interchanged meaning that either mancozeb or maneb can be used for the
same use pattern; and
• The degradation pathway for the two chemicals is similar in resultant chemical species
though rates mat differ. For example, rapid hydrolysis of maneb and mancozeb produce an
EBDC complex consisting of similar constituents although maneb hydrolyze faster than
mancozeb (neutral hydrolysis half-lives are 3 hours for maneb and 17 hours for mancozeb).
In this respect, the following describes how risks of mancozeb and maneb uses to CRLF will be
assessed. If more than one product containing an EBDC active ingredient (mancozeb, maneb, or
metiram) is used on a crop during the same growing season and the EBDC products used allow
different maximum poundage of active ingredient per acre per season, then the total poundage of all
such EBDC products used must not exceed the lowest specified individual EBDC product maximum
seasonal poundage of active ingredient allowed per acre. If the EBDC products used allow the same
maximum poundage of active ingredient per acre per season then the total poundage of all EBDC
products used must not exceed any one of the specified individual EBDC product maximum
application rate. Based on these limitations, mancozeb and maneb will be assessed together. The
only deviation from this is where there are uses that are only for mancozeb or maneb. In that
situation the chemicals will be assessed separately. Currently registered uses will be included in the
risk assessment while proposed new uses or mitigation measures noted in the RED but that have not
yet been adopted on pesticide labels, will be described in the risk characterization section.
Second, the unique chemical structure and degradation profiles of mancozeb and maneb require a
unique process to be adopted to determine risk quotients (RQs). Unlike other chemicals, the two
chemicals hydrolyze at a very rapid pace (within hours) in aquatic systems. This rapid degradation
of parent chemicals requires that the numerator (EECs) and dominator (toxicities) of the acute and
chronic RQs have to be assigned differently.
For each acute RQ, EEC of the EBDC complex is the value used for the numerator and acute
toxicity of relevant parent is the value used for the dominator. This is because the EBDC complex is
similar, in composition, to the EBDC complex that forms in laboratory media in which acute toxicity
is measured. Acute toxicity to organisms in the laboratory is determined for dissolved mancozeb
and maneb parents at concentrations below their solubility. At these concentrations, chemical
species present are similar to those chemical species present in a freshly formed EBDC complex in
the natural environment.
59
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For each chronic RQ, EEC of ETU is the value used in the numerator and acute toxicity of ETU is
the value used in the dominator. Therefore, it is assumed that chronic exposure EECs and toxicity
are mainly related to ETU. This assumption is considered reasonable because of two reasons: (1)
laboratory data suggests that the main constituents of aged EBDC complex are ETU and ETU
degradate; and (2) modeled exposure EECs cover the two known sources of ETU: aging of the
EBDC complex and limited release from degradation of bound species. In modeling for EECs, the
simulation stared with an ETU rate that is molecularly equivalent to the application rate of either
mancozeb or maneb (i.e., the exercise simulates, on molecular basis, degradation and transport of
maximum concentrations of ETU that may be formed from applied parents). Figure 2-13 contains a
summery of the above-described process for assigning acute and chronic values along with the basis
for such assignments.
In
one
day
At
both
21
and*
60
days
Exposure
Active Ingredients=Mancozeb or Maneb Parents
(Complete polymeric chains)
I
EECs for ETU
resulting from
equivalent
application of the
parent
EECs for the
constituents of
the EBDC
complex at the
short-term
resulting from
parent application
Initial
Hydrolysis
Fresh EBDC Complex
(At the short-term)a
Enriched with chemicals
present at the short-term)
Continued
Degradation
Aged EBDC Complex
(At the long-tenn)-
Enriched with ETU and ETU
degradates (chemicals
present at the long-term)
Effects
I
Toxicity data for
organisms
exposed to the
constituents of
the EBDC
complex at the
short-term
Toxicity data for
organisms
exposed to ETU
(ETU Chronic)
Rapid hydrolysis of applied mancozeb and maneb parents result in the formation of:
a= the fresh EBDC complex or the EBDC complex at the short-term. At this time, the complex is expected to be similar, in
composition, to the fresh EBDC complex that forms in submitted mancozeb and maneb acute toxicity studies. In these studies,
mancozeb and maneb parents were diluted to concentrations below, or up to, the solubility limit of 6 ppm for mancozeb and 120 ppm
for maneb. At this short term, the major constituents of the complex are: variable/low molecular weight polymeric chains or polymer
fragments, monomeric species and transient species.
Aging of this complex results in:
b= the aged EBDC complex or the EBDC complex at the long-term. At this time, the complex becomes relatively enriched with
ETU and ETU degradates. Therefore, effects of this aged complex is expected to be similar to those observed in submitted ETU
chronic toxicity studies on the reasonable assumption of toxicity being related to ETU and not ETU degradates. In these studies,
ETU was used as the only test substance.
60
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Figure 2-13 Summary of how modeled acute and chronic exposures in aquatic systems (acute and
chronic EECs) were chosen so that they can be related to laboratory measured acute and chronic
effects.
2.10.1 Measures of Exposure
Potential exposure pathways (i.e. runoff, spray drift, dietary residues on vegetation and insects)
result from foliar applications of mancozeb and maneb to agricultural crops, seed treatments,
horticulture and turf.
The measures of exposure will be estimated using models. Short and long-term aquatic exposures
will consist of aquatic EECs using Tier II simulation models PRZM and EXAMS13. These
simulations will be based on the constituents of the mancozeb/maneb complex. If available toxicity
data indicate that a pesticide formulation may be more toxic to aquatic biota than indicated by active
ingredient effects testing, and spray drift is a significant component of the aquatic exposure, it may
be necessary to consider aquatic exposure to the formulation. If there are any "May effect"
determinations in the aquatic exposure assessment, an analyses of spray drift buffers needed to get
below concentrations that exceed the endangered species level of concern will be conducted and a
dilution model will be used and described in the risk characterization section of this risk assessment.
Terrestrial exposure will be estimated using a model that assumes direct application to a variety of
avian, mammalian and reptilian food items. The chronic exposure will be based on mancozeb,
maneb, and ETU (the major degradate). A 90th percentile of the existing mancozeb and maneb foliar
residue data from California and Washington states will be used to determine the foliar dissipation
half life for terrestrial exposure assessments. Terrestrial wildlife exposure estimates are typically
calculated for birds and mammals, which are surrogates for terrestrial-phase amphibians and reptiles.
These estimates focus on potential dietary exposures to the pesticide active ingredient and are
estimated assuming the organisms are exposed to a singe pesticide residue on food items in a given
exposure scenario. Dietary residues will be modeled for mammals and birds (e.g. vegetation,
insects, seeds) using the conceptual approach given in the model T-Rex (version 1.3.1, 2006). In
addition, if there are any "may effect" determinations in the terrestrial exposure assessment,
terrestrial exposure and risk for the terrestrial-phase of the CRLF will be estimated using T-HERPS
(version 1.0, 2007), which is a modified version of T-REX (version 1.3.1) that allows for estimation
of food intake for herptiles. Birds are typically used as surrogates for reptiles and terrestrial-phase
amphibians. However, reptiles and terrestrial-phase amphibians (i.e., herptiles) tend to have much
lower metabolic rates and lower caloric intake requirements than birds or mammals. As a
consequence, birds are likely to consume more food than amphibians or reptiles on a daily dietary
intake basis, assuming similar caloric content of the food item. T-REX (version 1.3.1.) has been
altered to allow for an estimation of food intake for herptiles (T-HERPS) using the same basic
procedure that T-REX uses to estimate avian food intake (see Appendix E for details).
2.10.2 Measures of Effect
Measures of effect are based on changes in the attribute of an entity in response to a stressor and are
generally based on the results of a toxicity study, although monitoring data may also be used to
13 http://epa.bov/oppefedl/models/water/index.htm
61
-------
provide supporting lines of evidence for the risk characterization. Measures of acute effects (e.g.
LC50) and chronic effects (e.g., NOAEC) for aquatic and terrestrial organisms are derived from
registrant submitted data, literature data obtained from ECOTOX, and incident data. The measures
of effects will either be the results of tests on the specific organisms or will be derived or assumed
based on extrapolated effects endpoints. Where data are lacking and extrapolated effects endpoints
cannot be reliably estimated, risk will be presumed. In cases where risk is presumed, but cannot be
quantified based on lack of data, best professional judgment will be used to make reasonable
conservative assumptions.
2.10.3 Measures of Risk
Results of the exposure and toxicity effects data will be used to evaluate the likelihood of adverse
ecological effects on the CRLF. These effects will be estimated quantitatively using a deterministic
risk quotient approach based on application information provided on the product labels. The risk
quotient (RQ) is the ratio of the estimated environmental concentration (EEC) of a chemical to a
toxicity test effect (e.g., LC50) for a given species. The RQ as an index of potential adverse effects is
then compared to an Agency established Level of Concern (LOC) in order to identify when the
potential adverse effect is a concern.
As part of the risk characterization, an interpretation of acute RQ for listed species is discussed.
This interpretation is presented in terms of the chance of an individual event {i.e., mortality or
immobilization) should exposure at the EEC actually occur for a species with sensitivity to maneb or
mancozeb on par with the acute toxicity endpoint selected for RQ calculation. The individual effects
probability associated with the acute RQ is based on the mean estimate of the slope and an
assumption of a probit dose response relationship.
Indirect effects to the CRLF as a result of effects to terrestrial invertebrates will be assessed by
comparing the expected mancozeb and maneb residues on small and large insects (predicted by the
T-REX model) to the acute contact toxicity information for the most sensitive terrestrial invertebrate.
Review of mesocosm study conducted with mancozeb will be used to characterize potential risks.
In the ecological risk assessment used to support the RED, EFED evaluated numerous mancozeb
seed treatment uses. That evaluation considered use sites with only seed treatment, not seed and
foliar treatments. The results of that evaluation indicated that acute risks to endangered species LOC
would not be exceeded (RQs were below 0.01). Although maneb has numerous seed treatment uses
these were not assessed separately but instead, the mancozeb seed treatment assessment was used for
maneb as well. This would be protective of any potential risks from maneb seed treatment use
because; 1) maneb toxicity to birds on an acute oral exposure basis is less than mancozeb (the avian
acute oral LD50 of maneb (Bobwhite quail LD50 >2,150 mg/kg) is practically nontoxic to birds and
the avian acute LD50 for mancozeb (English sparrow LD50 -1,500 mg/kg, Mallard duck and
Japanese quail LD50s >6400); and 2) the exposure (rates of application) from these seed treatment
uses are similar for maneb and mancozeb. As is the case with terrestrial risk, potential aquatic risks
are considered minimal based on negligible aquatic exposure resulting from seed treatment
compared to the rate of application used for the assessed foliar treatment to the same crop. For
62
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example, seed treatments are equivalent to application rates of 0.002 to 0.315 lbs a.i/Acre compared
to seasonal foliar treatment rates ranging from 4.8 to 18 lb a.i/Acre.
There are several scenarios for which we will not determine RQs. These and the rationale for not
undertaking further work to determine RQs is presented below.
o Acute avian RQs will not be determined. EFED believes the acute dietary risk to birds from
exposure to mancozeb is low because 1) dietary testing attempted on mallard ducks and
bobwhite quail indicated an aversion to test diet (the birds would not consume the test material);
2) there is low acute toxicity of mancozeb to birds in multiple dosing LD50 studies; 3) there are
no incidents showing mancozeb has been responsible for bird kills or poisonings; and 4) maneb
(chemically related compound) is practically nontoxic to birds in dietary LC50 testing (mallard
duck LC50 > 5,000 ppm and bobwhite quail LC50 > 10,000 ppm). The acute dietary risks to
birds eating food items exposed to spray applications of maneb are also expected to be low.
Therefore, mancozeb and maneb uses will have no effect to avian species on an acute dietary
basis and will not be assessed further. .
o Acute mammalian RQs will not be determined. Chronic risks to terrestrial organisms associated
with mancozeb and maneb use drive this assessment. The acute endpoints were not definitive.
Also, EFED believes the acute dietary risk to mammals from exposure to mancozeb and maneb
is low. The mammalian acute oral LD50 is >5,000 for mancozeb and maneb. Therefore,
mancozeb and maneb uses will have no effect to mammalian species on an acute dietary basis
and will not be assessed further.
o RQs will not be determined for any taxa based on dip treatments. Dip treatment to Capri figs,
pineapples, and asparagus results in minimal potential risks. The intension of the dip treatment
is to kill fungus present on the surfaces of the plant and or seed pieces. Exposure resulting from
mancozeb and maneb dip treatments is considered very low because it is associated with minimal
amount of active ingredient adsorbed to the surface of the plant parts; octanol water partitioning
coefficient is very low for mane and mancozeb (Kow=5 and 21 respectively). Therefore, we
have determined that use of mancozeb and maneb for dip treatments results in no effect to the
CRLF and will not be further addressed in this assessment.
2.10.4 How Uncertainties are addressed in this Risk Assessment
Terrestrial Risks
o Terrestrial plant data are not available for mancozeb as a sole active ingredient in the Typical
Enduse Product (TEP). There is also no terrestrial plant data for maneb. Terrestrial plant data
for mancozeb is based on a TEP containing 60% mancozeb co-formulated with 9%
dimethomorph. In these studies the EC25 is higher than the highest concentration tested. In this
risk assessment the co-formulated data will be used qualitatively. Terrestrial plant incidents and
estimated EECs will be used in characterization. The resulting conclusions of the assessment
could be either an over or underestimation of risk.
63
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Aquatic Risks
o There is uncertainty regarding the risks to freshwater invertebrates from exposure to the bound
residues in sediment. The risk that might be associated with the sediment bound residue would
probably be associated with its possible conversion into ETU at low concentrations. This ETU
exposure is covered by the ETU modeling exercise. In this exercise, the application rate used
represents 100% transformation to ETU from the total amount of the applied parent.
Additionally, included in this assessment is a recently reviewed freshwater invertebrate toxicity
study conducted with ETU. The approach used in this risk assessment to address this uncertainty
results generally in an overestimation of risk.
o There are no chronic toxicity data for freshwater fish for ETU (the major degradate of mancozeb
and maneb). An estimated chronic freshwater fish NOAEC of 37.32 ppm was determined using
the acute-to-chronic ratio (ACR) approach. Acute and chronic invertebrate toxicity data
conducted with ETU was used to develop the ACR and then the ACR was applied to acute
freshwater fish toxicity data for ETU to estimate the chronic toxicity value for ETU. This
approach generally is an overestimate of risk.
o One study has been submitted for a maneb technical formulation and mancozeb technical
formulation using the freshwater green algae (P. subcapitatum). Typically, studies are available
for duckweed (Lemna gibba), blue-green algae (Anabaena jlos-aquae), freshwater green alga (P.
subcapitatum), and a freshwater diatom species to assess a cross-section of the non-target
freshwater aquatic plant population. This risk assessment will use the submitted P. subcapitatum
studies with mancozeb and maneb for the aquatic freshwater plant endpoint and characterize the
potential endangered species risk with available mixture data on freshwater aquatic plant species
and incident data. This approach could result in an overestimation or under estimation of risk.
64
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3 Exposure Assessment
3.1 Aquatic Exposure Assessment
For tier 2 surface-water assessments, two models are used in tandem. PRZM simulates fate and
transport on the agricultural field. The version of PRZM (Carsel et al., 1997) used was 3.12 beta,
dated May 24, 2001. The water body is simulated with EXAMS version 2.98.04, dated July 18,
2002 (Burns, 2004). Tier 2 simulations are run for multiple (usually 30) years and the reported
EECs are the concentrations that are expected once in ten years based on the thirty years of daily
values generated by the simulation. PRZM and EXAMS were run using the PE4 shell, dated May
14, 2003, which also summarizes the output. Spray drift was simulated using the AgDrift model
version 2.01 dated May 24, 2001.
3.1.1 Aquatic Exposure Modeling
3.1.1.1 Modeling Approach
Mancozeb and maneb are highly vulnerable to hydrolysis and are not expected to persist in surface
water as intact parents. Therefore acute and chronic aquatic exposures are expected to be associated
with the resultant suite of hydrolytic products, which is the EBDC complex. For modeling, the time-
line of aquatic exposure to the EBDC complex was categorized into short and long-term. In the
short-term, aquatic exposure is expected to result from chemicals forming immediately after
hydrolysis. In contrast, the long-term exposure is expected to be associated with chemicals related
to the process of ETU formation and degradation, that is ETU, ETU degradates, and the bound
residue (a suspected ETU producer; refer to mancozeb, maneb and ETU REDs:U.S. EPA a, b, and
c). Short-term exposure was based on fate and transport parameters using laboratory-measured
radioactivity associated with the group of chemicals present at this time line. Long-term exposure
was based on the available fate and transport parameters of ETU (ETU was used as the test
substance).
In order to produce aquatic EEC values for both the short and long-term, two separate modeling
exercises were carried out using Tier II linked PRZM/EXAMS. The first modeling exercise
consisted of model runs to arrive at EECs for the short-term constituents of the acute EBDC complex
using laboratory determined fate and transport parameters. The second modeling exercise consisted
of model runs to arrive at chronic
3.1.1.2 Modeling Inputs
The two modeling exercises were executed using crop specific or surrogate scenarios. Necessary
inputs for each of these simulations consisted of the following:
First, A scenario that represents a crop or "group of crops" along with the maximum application
rate, maximum number of applications, minimum application interval and the expected application
date. Representative scenarios for various crop use patterns and application parameters used in the
short and long term modeling are listed in Table 3-1.
65
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Table 3-1 Representative scenarios and application parameters
California
MAR*
/IIa)
PR/M
Scenario
Crop (s) Represented
Chemical.*
Short-term
exercise
Long-term
exercise
1/.Y 1*
.1/1/"
(days)
Date*
(dtl-mni)
Almond
Almonds
Mn
7.1744
0.6887
4
1
01-02
Cole crop
Brassica: Broccoli, Cabbage, Chinese
Cabbage (tight head), Cauliflower, and
Kohirabi
Mn
1.7936
0.1722
6
1
07-01
Chinese Cabbage (loose head)
Mn
1.3452
0.1291
6
1
07-01
Kale
Mn
1.7936
0.1722
2
1
07-01
Corn
Corn (field & seed crop)
Mz
1.3452
0.1291
10
4
01-05
Corn (Sweet/Pop)
Mn
1.3452
0.1291
5
3
07-01
Mz
1.3452
0.1291
5
4
07-01
Cotton
Cotton
Mz
1.7936
0.1722
4
10
15-06
Forestry
Forestry (Douglas Fir)
Mz
3.5872
0.3444
3
14
01-03
Fruit
Apples, Crab apple, Pear, and Quince
Mz
5.3808
0.5166
4
7
15-03
Apples
Mn
5.3808
0.5166
4
7
15-03
Bananas and Plantains
Mz
2.6904
0.2583
10
14
01-03
Bananas
Mn
2.6904
0.2583
10
14
01-03
Papayas
Mz
2.242
0.2152
14
14
15-02
Mn
2.242
0.2152
14
14
15-02
Figs
Mn
2.6904
0.2583
1
N/A
01-03
Garlic
Garlic
Mz
2.6904
0.2583
10
7
15-03
Mn
2.6904
0.2583
10
7
15-03
Grapes
Grapes
Mz
2.242
0.2152
3
7
15-02
Mn
2.242
0.2152
3
7
15-02
Lettuce
Lettuce (leaf & head) and Endive
Mn
1.7936
0.1722
4
7
07-01
Brussels sprouts
Mn
1.7936
0.1722
6
7
07-01
Melons
Cucurbits
Mz
2.6904
0.2583
8
7
15-06
Cucurbits
Mn
1.7936
0.1722
8
7
15-06
Nursery
X-mass tree plantations
Mz
3.5872
0.3444
3
14
01-04
Ornamentals (Nursery)
Mz
1.51335
0.1453
3
7
01-03
Mn
1.3452
0.1291
3
7
01-03
Onion
Onion (Dried) and Shallot
Mz
2.6904
0.2583
10
7
15-03
Fennel
Mz
1.7936
0.1722
8
7
07-01
Onion (Green)
Mn
2.6904
0.2583
7
7
07-01
Potato
Potatoes
Mz
1.7936
0.1722
7
3
15-03
Mn
1.7936
0.1722
7
5
15-03
Residential/i
mpervious
surfaces
Ornamentals: Ground cover,
Herbaceous, Non-flowering, Shade
trees, and Woody shrubs and vines
Mz
1.51335
0.1453
5
7
15-03
Mn
1.3452
0.1291
3
7
15-03
Ornamentals (Pachysandra)
Mz
19.5054
1.8725
5
10
15-03
Mn
15.5819
1.4959
4
7
15-03
Turf (Residential)
Mz
21.4111
2.0555
4
5
15-03
Mn
19.5054
1.8725
4
7
15-03
Row crop
Asparagus
Mz
1.7936
0.1722
4
10
01-03
Beans (Dried)
Mn
1.7936
0.1722
6
5
01-04
Pepper
Mn
1.7936
0.1722
6
7
01-03
Sugar beet
Sugar Beet
Mz
1.7936
0.1722
7
7
01-02
Mn
1.7936
0.1722
7
7
01-02
Tomato
Tomatoes
Mz
1.7936
0.1722
4
7
01-03
Mn
1.7936
0.1722
4
7
01-03
Eggplant
Mn
1.7936
0.1722
7
7
15-05
Turf
Turf: commercial, Golf course,
Mz
21.4111
2.0555
4
5
07-01
66
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California
MAR*
Kg/Ha)
PRZM
Scenuru>
Crop (s) Represented
Chemical*
Short-term
exercise
Long-term
exercise
MSA*
MAI*
(days)
Date*
(dd-mm)
Industrial, recreational, and Sod farms
Mn
19.5054
1.8725
4
1
07-01
Wheat
Wheat, Barely, Oats, Rye, and
Triticale
Mz
1.7936
0.1722
3
1
15-02
Mz
2.242
0.2152
3
1
15-02
Wine grapes
Grapes (Wine)
Mn
2.242
0.2152
3
1
15-02
* Mz= Mancozeb; Mn= Maneb; MAR= Maximum application rate; MNA= Maximum number of applications; MAI=
Minimum application interval; and Date= Application Date.
In modeling, the rate used for the short-term exercise is the parent mancozeb or maneb in kg a.i./ha
(e.g., almonds rate= 6.4 lb a.i./A multiplied by 1.121= 7.174 kg/Ha). However the rate used for the
long-term exercise is the ETU rate, which was calculated by assuming very rapid and complete
degradation of applied EBDCs to ETU. The ETU rate was based on the maximum conversion rate
of 9.6%14 for parent mancozeb or maneb entering the soil system. For example the equivalent long-
term rate for almonds in the table above= the short-term rate (7.174 kg/ha) multiplied by 0.096
giving a rate equal to 0.6887 kg/ha.
Second, the physiochemical, fate and transport properties along with other parameters necessary for
modeling: Table 3-2 contains a summary of the inputs used in the short-term and long-term
simulations.
Table 3-2 PRZM/EXAMS Input parameters for mancozeb and maneb for the short and long term
simulations
Input Parameter t'R/.M I'.\ I \IS Parameters I sed for Simulations 1 Rcjcrcncc
I /'llic Short-term \1 the l.ong-lerm
Study MRU) \nmhcr
Mancozeb (M-) Maneb (Mn) i'.il from M-orMn
Molecular Wt.
(grams)
265
265.36
102.2
Registrant data
Vapor Pressure
(torr)
1.003 e 7
7.577 e"8
9.728 e"1
Registrant data
Bacterial Bio-lyses
in the water column
(days)
44
90th percentile
From two
values (38, and
41)
24
12x2=24
6.28
3.14x2=6.28
Mz: 462043-01
Mn & ETU: No studies
14 This value of 9.6% was the maximum conversion rate observed in laboratory aerobic soil studies
on a concentration basis (i.e., after multiplying the reported rate by 38.5%, the molar conversion of
parent mancozeb or maneb to ETU).
67
-------
Input Parameter t'K/.M i'.\ WIS Parameters I seil for Simulations 1 Kejerence
I /' the Short-term \t the Lung-term
Slmlv \JHII) \nmher
\l(inco:eh (\J:J Uaneh(Mn) I '.H jrom M:. or Mn
Bacterial Bio-lyses
in benthic sediment
(days)
0
(Stable)
435
One value
(145x3)
447
One value
(149x3)
Mz: See Note 2
Mn: 001633-35
ETI: 402582-03
Aerobic Soil
Metabolism Half-
life (days)
29
90th percentile
From three
values (29, 20,
and 21)
12
90th
percentile
From three
values (12,
8, and 8)
3.14
90th percentile three
values (1.4, 3, and
3.2)
Mz: 457445-01
Mn: 405852-01, and 451452-02
ETU: 451564-01
Application
Method
Aerial Or Ground
Product Label
Incorporation depth
0 (inches)
Product Label
Application
Efficiency
0.95 (aerial) Or 0.99 (ground) as a fraction
Guidance
Spray Drift
(fraction)
0.05 (aerial) Or 0.01 (ground) the short-term; and
0.123 (aerial) Or 0.025 (ground) the short-term
Guidance
And Note3
Solubility (ppm)
6
150
20,000
Registrant data
Mz: 405883-02
Koc(LKg-l)
1,167
(Average
value)
946
(Average
value)
288
(Average
value)
Mn: 405852-03, 400472-01,
455959-01, 455959-02
ETU: 002588-96,
000971-58
Mz: See Note 2
pH 7 Hydrolysis
Half-life (days)
4
(Same as Maneb)
0
(Stable)
Mn: 453936-01
ETU: 404661-03
Mz: 001621-03
Photolysis Half-life
(days)
0
(Stable)
1
Mn: 404656-02
ETU: See Note 4
1 Values were chosen as per: Guidance for Chemistry and Management Practice Input Parameters For Use in Modeling
the Environmental Fate and Transport of Pesticides, Version 2/November 7, 2000.
2 Although there was an anaerobic aquatic study (MRID 000888-20) and hydrolysis studies (000971-62 and 402582-01)
for mancozeb, the half-lives could not be calculated because of problems in identification of degradates using the TLC
method.
3 The ETU rate specified in the table is accurate only for the soil system and needs to be corrected for the aquatic
system. Therefore, a correction factor of 2.458 was used and was affected by changing the drift from 0.05 (the default
68
-------
value) to 0.123 (0.05x2.458) or from 0.01 (the default value) to 0.025 (0.01x2.458). Changing the drift fraction by the
stated factor will result in an exact account for the observed 23.6% parent/ETU conversion rate in aquatic systems.
4 Indirect photolysis in natural waters (1-4 days) as reported by: Sue Xu. 2000. Environmental Fate of Ethylenethiourea,
California Department of Pesticide Regulations, CA, USA; and IUPAC. 1977. Ethylenethiourea, Pure & Appl. Chem.
49, 675-689.
3.1.1.3 Modeling Results
The results obtained from the two simulations are included in Table 3-3. EECs used for the aquatic
risk assessment were the acute peak values from the short-term simulations and the chronic 21- and
60-day EECs from the long-term simulations.
Table 3-3 EECs for the short and long-term constituents of the EBDC complex resulting from
mancozeb and maneb (ppb)
Crop
Weather Station
Peak
(short-term)
21-day
(Long-term)
60-day
(Long-term)
(1) Crop patterns tor mancozeb use
Asparagus
San Francisco (W23234)
8.85
1.30
0.92
Cereal Grains (2)
Fresno, CA(W93193)
24.16
1.89
1.01
Corn (Field & seed crop)
Sacramento (W23232)
16.84
1.90
1.25
Cotton
Fresno, CA (W93193)
8.25
0.74
0.48
Crab apple, pear, and quince
Fresno, CA (W93193)
20.27
4.78
2.69
Fennel (one crop)
Bakersfield (W23155)
13.97
0.97
0.87
Fennel (two crops)
Bakersfield (W23155)
14.22
1.49
1.23
Forestry (Douglas Fir)
Arcata/Eureka (W24283)
40.55
3.34
2.09
Plantains
Fresno, CA(W93193)
10.83
1.63
1.47
Shallot
Bakersfield (W23155)
11.30
2.58
2.35
X-mass tree plantations
San Diego, CA (W23188)
32.02
2.61
1.57
(2) Crop patterns for maneb use
Almonds
Sacramento (W23232)
45.62
7.19
4.26
Beans (Dried)
San Francisco (W23234)
10.64
2.08
1.21
Brassica (1) (one crop)
Sacramento (W23232)
32.09
2.97
2.12
Brassica (1) (three crops)
Sacramento (W23232)
38.09
3.01
2.79
Brassica (1) (two crops)
Sacramento (W23232)
38.09
3.00
2.78
Brussels sprouts (one crop)
Santa Maria (W 23273)
59.48
3.78
2.77
Brussels sprouts (two crops)
Santa Maria (W 23273)
59.89
4.29
3.72
Cabbage (Chinese)/Loose (one crop)
Sacramento (W23232)
35.95
3.38
1.79
Cabbage (Chinese)/Loose (three crops)
Sacramento (W23232)
63.69
5.28
4.11
Cabbage (Chinese)/Loose (two crops)
Sacramento (W23232)
51.84
4.80
3.09
Eggplant
Fresno, CA(W93193)
7.87
1.02
0.81
Figs
Fresno, CA(W93193)
6.71
0.90
0.41
Kale (one crop)
Sacramento (W23232)
20.28
1.92
0.92
Kale (three crops)
Sacramento (W23232)
32.09
2.97
2.12
Kale (two crops)
Sacramento (W23232)
24.54
2.90
1.53
Lettuce, and Endive (one crop)
Santa Maria (W 23273)
36.68
3.25
1.78
Lettuce, and Endive (two crops)
Santa Maria (W 23273)
59.48
4.13
3.26
Onion (Green) (one crop)
Bakersfield (W23155)
17.21
3.08
2.40
Onion (Green) (two crops)
Bakersfield (W23155)
17.35
3.19
3.04
69
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Crop
Weather Station
Peaii
(slwrt-terin)
21-day
(Long-term)
60-day
(Long-term)
Pepper
San Francisco (W23234)
13.36
1.63
1.16
Walnuts
Sacramento (W23232)
16.32
2.64
2.37
(3) Crop patterns for interchangeable use of manco/el) or mancb
(a) for modeling: manco/el) was assumed to be applied
Apples
Fresno, CA(W93193)
20.27
4.78
2.69
Bananas
Fresno, CA(W93193)
10.83
1.63
1.47
Corn (Sweet/Pop) (one crop)
Sacramento (W23232)
57.09
3.64
1.88
Corn (Sweet/Pop) (three crops)
Sacramento (W23232)
95.04
5.02
3.85
Corn (Sweet/Pop) (two crops)
Sacramento (W23232)
71.51
4.93
3.16
Cucurbits (3)
Fresno, CA (W93193)
11.36
1.52
1.38
Garlic
San Diego, CA (W23188)
41.36
2.93
2.57
Grapes
Fresno, CA(W93193)
10.16
1.74
0.95
Grapes (Wine)
San Francisco (W23234)
11.84
1.83
0.93
Onion (Dried)
Bakersfield (W23155)
11.30
2.58
2.35
Ornamentals (Nursery)
San Diego, CA (W23188)
19.47
1.69
1.03
Ornamentals (residential) (4)
San Francisco (W23234)
0.72
0.08
0.04
Ornamentals (residential/Pachysandra)
San Francisco (W23234)
7.60
1.00
0.60
Ornamentals (Residential/turf)
San Francisco (W23234)
11.54
1.26
0.68
Papayas
Fresno, CA(W93193)
10.16
1.43
1.30
Potatoes
Bakersfield (W23155)
11.95
2.85
1.45
Sugar Beet
Fresno, CA(W93193)
22.26
1.91
1.42
Tomatoes
Fresno, CA(W93193)
9.56
1.78
0.99
Turf (5)
San Francisco (W23234)
103.51
23.30
12.68
Turf (sod farms only) (two crops)
San Francisco (W23234)
132.00
33.20
23.14
(b) for modeling: mancb was assumed to be applied
Apples
Fresno, CA(W93193)
20.01
4.78
2.69
Bananas
Fresno, CA(W93193)
10.53
1.63
1.47
Corn (Sweet/Pop) (one crop)
Sacramento (W23232)
46.74
4.03
2.06
Corn (Sweet/Pop) (three crops)
Sacramento (W23232)
91.78
6.73
4.45
Corn (Sweet/Pop) (two crops)
Sacramento (W23232)
65.44
5.93
3.43
Cucurbits (3)
Fresno, CA (W93193)
5.78
1.02
0.92
Garlic
San Diego, CA (W23188)
37.93
2.93
2.57
Grapes
Fresno, CA(W93193)
10.03
1.74
0.95
Grapes (Wine)
San Francisco (W23234)
11.28
1.83
0.93
Onion (Dried)
Bakersfield (W23155)
9.77
2.58
2.35
Ornamentals (Nursery)
San Diego, CA (W23188)
13.76
1.29
0.65
Ornamentals (residential) (4)
San Francisco (W23234)
0.39
0.06
0.03
Ornamentals (residential/Pachysandra)
San Francisco (W23234)
4.71
0.68
0.49
Ornamentals (Residential/turf)
San Francisco (W23234)
6.22
1.01
0.56
Papayas
Fresno, CA(W93193)
9.05
1.43
1.30
Potatoes
Bakersfield (W23155)
9.36
2.40
1.86
Sugar Beet
Fresno, CA(W93193)
21.27
1.91
1.42
Tomatoes
Fresno, CA(W93193)
8.86
1.78
0.99
Turf (5)
San Francisco (W23234)
92.47
18.96
11.30
Turf (sod farms only) (two crops)
San Francisco (W23234)
111.07
22.91
19.24
Note 1: Brassica Include: broccoli, cabbage and Chinese cabbage (tight head), cauliflower, and kohlrabi
Note 2: Cereal grains include: wheat, barley, oats, rye, and triticale
70
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Note 3: Cucurbits: cucumber, cantaloupe, honey dew, casaba melon, crenshaw melon, and watermelon for both
mancozeb and maneb in addition to musk melon and gourds for mancozeb only; and winter squash and pumpkins for
maneb
Note 4: Ornamentals used in residential landscaping including: shade trees, ground cover plants, herbaceous plants,
Note 5: Turf excludes residential turf but includes: commercial/industrial/recreational area lawns, golf course turf, and
ornamental sod farm turf.
3.1.2 Aquatic Monitoring
Mancozeb and maneb are highly vulnerable to hydrolysis and are not expected to persist intact in
surface water. Maneb is expected to hydrolyze faster than mancozeb and both are expected to
produce a suite of chemicals referred to as the EBDC complex. A USGS/NAWQA 15 database
search for mancozeb and maneb resulted in "no data returned for those criteria". The same results
were obtained from EPA/STORET 16 and the CALDPR surface water database17. Additionally, the
CALDPR 18 ground water database reported no detections of maneb in 583 wells in 27 counties (the
cumulative well inventory report for the period from 1986-2003). In contrast to parents, sporadic
detections of the main metabolite ETU have been reported in both surface and ground water. For
example, a value of 16 ppb was recorded beneath an Iowa apple orchard, which had been treated
with an EBDC fungicide (USGS/NAWQA). In California, it appears that no monitoring was
executed for ETU in surface water, however, ETU was detected once at an unconfirmed
concentration of 0.725 ppb in one well out of 583 (the cumulative well inventory report for the
period from 1986-2003).
In a 2-year targeted surface water and ground water monitoring program conducted by the EBDC
Task Force19 many locations around the US (MRID 46145401). No ETU was measured above the
limit of detection of 0.1 ppb in either raw or treated community surface water sources. Sampling
was executed every 14-days during the historical EBDC use season. In the same study, targeted
ground water monitoring indicated a peak of 0.21 ppb measured in a public drinking water well
located in Lee County, Florida. In rural areas, the highest value measured by the EBDC Task Force
was 0.57 ppb and was for ground water from a private well near an EBDC treated field in an apple
growing region of New York. ETU concentrations in the range of 0.1 to 0.25 were also measured in
8 out of the 125 monitored rural wells.
3.1.3 Down-stream Dilution Analysis
Down-stream dilution analysis is necessary to define the full extent of the action area. This is
because the action area is defined by the initial area of concern or "footprint" of potential uses which
is extended by downstream dilution (this analysis) and by drift (see to 3.3.3, below). This analysis
determines downstream extent of exposure in streams and rivers where the EEC could potentially be
above levels that would exceed the highest RQ to LOC ratio. Based on all aquatic RQs, the greatest
RQ to LOC ratio for all aquatic organisms (plants and animals) are determined for various use
patterns (Table 3-4).
15 http://infotrek.er.usgs.gov/traverse/f?p=136:23:0:QUERY:NO
16 http://www.epa.gov/storet/dw home.html
17 http://www.cdpr. ca. gov/docs/em on/ surfwtr/ surfcont. htm
18 http://www.cdpr.ca.gov/docs/emon/grndwtr/wellinv/wirmain.htm
19 The EBDC Task Force ia a task force consisted of the registrants of the EBDC chemicals mancozeb, maneb and
metiram
71
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Table 3-4 A summary of the highest RQ to LOC ratios for various use categories
Category
Use Pattern
Species
RQ.
LOC
Ratio
(1) Mancozeb Use Only
Cultivated crops
X-mass trees*
Rainbow trout
0.07
0.05
1.4
Orchards & Vineyards
Pear
0.04
0.8
Forestry
Forestry
0.09
1.8
(2) Maneb Use Onlv
Cultivated crops
Loose Cabbage
Rainbow trout
1.09
0.05
21.8
Orchards & Vincvards
Almonds
1.52
30.4
(3) Mancozeb and Maneb Use
Cultivated crops
Corn (sweet & pop)
Rainbow trout
2.19
0.05
43.8
Orchards & Vineyards
Grapes
0.24
4.8
Turf
Turf
2.64
52.8
* Note: GIS mapping considered this use pattern as part of the cultivated crops category.
The ratios in Table 3-4 would be used to determine the downstream extent of the action area. For
example, the ratio of 1.4, for x-mass trees, is used to identify all stream reaches downstream from
the initial area of concern where the Percent Cropped Area (PCA) for the land uses identified, for
mancozeb only, are greater than 1/1.4 or 71%. All streams identified as draining upstream
catchments greater than 71% of the land class of concern, would be considered part of the action
area.
The total length of streams in the initial area of concern to the total length of California streams are:
57%) (189,441 km) for mancozeb use, 18%> (58,619 km) for maneb use, and 22% (72,553 km) for the
combined mancozeb and maneb use. By applying the down stream approach described above, the
total length added increased by 2% for mancozeb use, 9%> for maneb use, and 10%> for the combined
mancozeb and maneb use. It is noted that stream lengths of the initial area of concern is the highest
for mancozeb use followed by mancozeb and maneb use and finally by maneb use. This may be
attributed to the use of mancozeb in forestry. In this respect, it is noted that there were no reported
usage of mancozeb in the PUR data. Detailed analysis is included in Appendix C, for mancozeb
use, Appendix I for maneb use, and Appendix L for the combined mancozeb and maneb use).
3.2 Terrestrial Animal Exposure Assessment
3.2.1 Terrestrial Exposure Modeling
The terrestrial exposure model, T-REX (Version 1.3.1, dated December 7, 2006), is used to estimate
exposures and risks to terrestrial animals, including birds, mammals, and terrestrial invertebrates.
Input values on chemical application, avian and mammalian toxicity as well as foliar dissipation
half-life data are required to run the model. For the exposure estimate, the 90th percentile of the
foliar residue data (mancozeb and maneb were both 20 days) was used to determine the half life.
Only the data from the Western states were used to account for information indicating half lives
were typically twice as long in the west as in the east (Dole and Dawson, 2003). The mancozeb and
maneb foliar residue data represented the parent chemical as well as ETU. The application rates for
the; estimated lowest, middle and highest exposure uses for mancozeb, maneb, and joint
72
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mancozeb/maneb uses were modeled. To determine the chronic RQs, maneb's mammalian and
avian chronic toxicity endpoints were used to represent the parent chemical and ETU for the joint
mancozeb/maneb uses and the Maneb only uses. Mancozeb's mammalian and avian chronic toxicity
endpoints were used to represent the parent chemical and ETU for mancozeb only uses. The
toxicity endpoints for mammalian developmental and reproduction data for mancozeb, maneb and
ETU indicate that the toxicity endpoint for ETU (5mg/kg-bw) is similar to maneb (3.75mg/kg-bw).
The T-REX model generates estimated environmental concentrations (EECs) and calculates risk
quotients (RQs). Specifically, the models provides estimates of upper bound and mean
concentrations of chemical residues on the surfaces of different food items that may be sources of
dietary exposure to the CRLF in the terrestrial-phase (e.g., small and large insects, small mammals
and terrestrial invertebrates). The surface residue concentration (ppm) is estimated by multiplying
the application rate (pounds active ingredient per acre) by a value specific to each food item.
Information regarding the T-REX model can be found in Appendix F. Model inputs and estimated
terrestrial dietary exposures are provided in Table 3-5.
Table 3-5 T-REX model inputs for Mancozeb and Maneb uses; Half-life was assumed to be 20
days1 for all uses
l/pper-bound EECs (ppm)
Use
Kate
(lbs a.L/A)
Minimum
Interval
(Days)
Max. No.
Applications
Per Year
Short dross
Long
Grass
Broadleaf
Plants. Small
Insects
Emits. Pods.
Seeds. Large
Insects
Turf2
17.4
i
4
12039.93
5518.30
6772.46
752.50
Cucumbers2
2.4
i
8
2289.96
1049.56
1288.10
143.12
Ornamentals (other)2
1.2
i
3
691.25
316.82
388.83
43.20
Almonds3
6.4
i
4
4428.48
2029.72
2491.02
276.78
Beans (dried)3
1.6
5
6
1560.21
715.10
877.62
97.51
Figs
2.4
N/A
1
576.00
264.00
324.00
36.00
Shallot4
2.4
7
10
2437.56
1117.21
1371.13
152.35
Fennel4
1.6
7
8
1526.64
699.71
858.73
95.41
Cereal Grains4
1.6
7
3
921.66
422.43
518.43
57.60
1 For foliar degradation, foliar half-lives measurements used (Maneb: MRID #420449-04, #451946-01, #419615-01;
Mancozeb MRID #s 449596-01, 418369-01, 411339-01, 418369-02, 449596-03, 449585-01). Assuming these values
are distributed normally, the value which represents the one tail upper 90% confidence limit of the mean is 20 days.
2 Joint Mancozeb/Maneb uses
3 Maneb only uses
4Mancozeb only uses; Cereal grains: barley, oats, rye, triticale, and wheat
EECs on food items may be compared directly with dietary toxicity data or converted to an oral
dose, as is done for small mammals. For mammals, the residue concentration is converted to daily
oral dose based on the fraction of body weight consumed daily as estimated through mammalian
allometric relationships. The base-line risk assessment for mancozeb and maneb uses upper bound
predicted residues as the measure of exposure.
73
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3.3.2 Terrestrial Atmospheric Monitoring
Air monitoring data reported by the CDPR show that only mancozeb was included in the monitoring
program (Kollman, 2002). In this program, pesticide concentrations were measured in close
proximity to a field at the short-term; during and after pesticide application (15-20 meters from the
edge of the treated field during/just after pesticide application) and in the ambient community air at
the long-term (at three sites further ">1 km" from the application site and within longer periods from
the time of application). Although the study did not distinguish between the routes of transport
associated with observed detections, the close proximity of the location of the air monitoring sites to
the application site suggests that these detections are probably related to spray drift rather than long-
range atmospheric transport. For mancozeb, the two types of monitoring were conducted in Kern
County in 1993 after aerial application of mancozeb to a potato field. Mancozeb was not detected at
the long-term monitoring (limit of detection= 2 ppt) while it was detected at the short-term in the
range of 0.02 to 0.13 ppb in 46% of the 93 samples analyzed. Observed mancozeb detection level at
the long-term was compared to the group of pesticides reported to have moved into the Sierra
Nevada ecosystems (Fellers et al., 2004). In contrast to mancozeb no detection (over the
concentration of 2 ppt), the reported long-range transport pesticides detections ranged from 6.7 to
56.9 ppt in more than 80% of the time). The comparison suggests that the potential for long-range
transport of mancozeb is relatively small. Given similarities in the physiochemical properties
between mancozeb and maneb, similar conclusions can probably be drawn for maneb.
For ETU, partitioning into the air from dry soil/plant surfaces is expected (vapor pressure=
9,728x10"' torr). However, ETU's high water solubility results in relatively low Henry's law
constant (3.4X10"7 atm. m3 mole"1) and renders such partition unimportant because ETU forms only
when water is present (i.e. in wet soil or water bodies). Additionally, if ETU reaches air it is
expected to partition into rain or is not expected to persist as it is affected by OH-radicals present in
the air (a half-life of 0.9 hours was predicted by EPI suite). Data collected from a micro-agro-
ecosystem chamber indicate that small amounts of ETU may volatilize from soil and plant surfaces
(Nash and Beall, 1980). However, ETU was not detected in a US ambient air-monitoring study of
the US EPA designated 189 Hazardous Air Pollutants (Kelly et al, 1994)
3.2.3 Drift Analysis
Spray drift analysis is necessary to define the full extent of the action area. This is because the
action area is defined by the initial area of concern or "footprint" of potential uses which is extended
by drift (this analysis) and downstream dilution (refer to 3.2.3, above). Spray drift analysis
determines the additional distance from the treated area where listed species LOCs are exceeded as a
result of spray drift. This distance is based on the taxonomic group that yields the largest RQ to
LOC ratio. Both terrestrial and aquatic taxonomic groups are considered in this analysis.
For mancozeb, maneb, and mancozeb and maneb combined use patterns, the results of the screening-
level assessment indicate that the mammalian "RQ to LOC ratio" is highest. The results of the spray
drift analysis are summarized in Table 3-6 for the various use patterns.
Table 3-6 A summary of buffer distances obtained by AgDISP along with important parameters
used in modeling (species used for calculating RQs is laboratory rat).
74
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Use Category: Use Pattern
Determination of Species with Largest RQ to LOC Ratio
Buffer (ft) 4
EEC (ppm)
Toxicity (ppm)
HQ
LOC
Ratio
(1) Mancozeb Use Onlv
Cultivated crops: Shallot
2,437.56
120
80.70
1
80.70
2.051 to 2.067
(2) Maneb Use Onlv
Orchards & Vincvards: Almonds
4.428.48
75
234.57
1
234.57
2.913 to 3.002
(3) Mancozeb and Maneb Use
Turf: Turf
12,039.93
75
637.73
1
637.73
3,494 to 3,615
• Range was obtained by changing the volume of product used to prepare a 15 gallons finished spray.
The ranges of buffers are expected to vary depending on the application parameters used as these
parameters change not only with change in droplet size distribution but also with formulation type
and % of a.i. among many others. Appendix G contains a summary of input parameters used in this
analysis.
The total areas of the initial areas of concern are: 90,467 sq km for mancozeb use, 35,565 sq km for
maneb use, and 43,834 sq km for the combined mancozeb and maneb use. The initial area of
concern for mancozeb is the highest as a result of forestry use (no forestry use for maneb).
Application of the maximum buffers distances in the above Table, results in an increase of the initial
action area by nearly 80% for mancozeb use, 81% for maneb use, and 93% for mancozeb and maneb
use. Detailed analysis is included in Appendix C, for mancozeb use, Appendix I for maneb use, and
Appendix L for the combined mancozeb and maneb use).
75
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4 Effects Assessment
This assessment evaluates the potential for mancozeb and maneb to adversely affect the California
Red Legged Frog (CRLF). As previously discussed in Section 2.8, assessment endpoints for the
CRLF include direct toxic effects on the survival, reproduction, and growth as well as indirect
effects such as reduction of the prey base or modification of its habitat. Direct effects to the aquatic-
phase of the CRLF are based on toxicity information for freshwater fish, while the terrestrial-phase
is based on avian toxicity data since birds are generally used as a surrogate for terrestrial-phase
amphibians. Given that the frog's prey items and habitat requirements are dependent on the
availability of freshwater fish and invertebrates, small mammals, terrestrial invertebrates, and
aquatic and terrestrial plants, toxicity information for these taxa are also discussed. Acute (short-
term) and chronic (long-term) toxicity information is characterized based on registrant-submitted
studies and a comprehensive review of the open literature on mancozeb, maneb and ETU.
As described in the Agency's Overview Document (U.S. EPA, 2004a), the most sensitive endpoint
for each taxon is used for risk estimation. For this assessment, evaluated taxa include freshwater fish
(surrogate for aquatic-phase amphibians), freshwater invertebrates, birds (surrogate for terrestrial-
phase amphibians), mammals, terrestrial invertebrates, and aquatic plants. (See Section 4.1.3 for
more discussion).
Toxicity endpoints are established based on data generated 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) (U.S. EPA, 2004). In
order to be included in the ECOTOX database, papers must meet the following minimum criteria:
the toxic effects are related to single chemical exposure;
the toxic effects are on an aquatic or terrestrial plant or animal species;
there is a biological effect on live, whole organisms;
a concurrent environmental chemical concentration/dose or application rate is reported; and
there is an explicit duration of exposure.
Data that pass the ECOTOX screen are evaluated 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 that are more conservative than the registrant-submitted data are
considered. The degree to which open literature data are quantitatively or qualitatively characterized
is dependent on whether the information is relevant to the assessment endpoints {i.e., maintenance of
CRLF survival, reproduction, and growth) identified in Section 2.8. For example, endpoints such as
behavior modifications are likely to be qualitatively evaluated unless quantitative relationships
between modifications and reduction in species survival, reproduction, or growth are available.
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4.1 Toxicity of Mancozeb, Maneb and ETU to Aquatic Organisms
Table 4-1 summarizes the most sensitive aquatic toxicity endpoints for the CRLF, based on an
evaluation of both the submitted studies and the open literature, as previously discussed. A brief
summary of submitted and open literature data considered relevant to this ecological risk assessment
for the CRLF is presented below. Additional information is provided in Appendix D and H.
Table 4-1 Aquatic Toxicity Profile for mancozeb, Maneb, and ETU
Assessment
Endpoint
Measures of Ecological Effects
MRU)
Study
Classification
Direct toxicity to
Mancozeb: Rainbow trout (Oncorhynchus mykiss) LC50 =
460 ppb (Probit slope assumed to be 4.5s).4
40118502
Acceptable
aquatic-phase
CRLF
Maneb : Oncorhynchus mykiss LC50 = 42 ppb (Probit slope =
2.8 (p<0.05)23
40706001
Supplemental
ETU: Oncorhynchus mykiss estimated NOAEC =37.32ppm
1234
Estimated
Mancozeb: Daphnid (Daphnia magna) LC50 =580ppb (Probit
slope assumed to be 4.5s).4
40118503
Acceptable
Indirect toxicity to
Maneb: Daphnia magna EC50 =120 ppb (lowest measured
slope =4.2 (p<0.05))
40749402
Acceptable
aquatic-phase
CRLF (via toxicity
to prey items)
ETU: Daphnia magna NOAEC = .002ppb
46462901
Supplemental
Mancozeb freshwater green algae (Pseudokirchneriella
ubcaptitatu) EC50 = 47.0ppb
43664701
Acceptable
Maneb (,Pseudokirchneriella subcaptitatum) EC50 = 3.4ppb,
40943501
Acceptable
Based on the acute-to-chronic ratio
2
Joint Mancozeb/Maneb uses
3
Maneb uses only
4
Mancozeb uses only
5Raw data unavailable to estimate slope; Used default assumption cited in Urban and Cook (1986)
Acute toxicity to aquatic animals is categorized using the system shown in Table 4-2 (U.S. EPA,
2004). Toxicity categories for aquatic plants have not been defined. Based on these categories,
mancozeb is classified as highly toxic to freshwater fish, invertebrates, and amphibians on an acute
exposure basis and maneb is classified as very highly toxic to freshwater fish and highly toxic to
freshwater invertebrates and amphibians on an acute exposure basis.
Table 4-2 Categories of Acute Toxicity for Aquatic Animals
Toxicity Category
<0.1 mg/L
Very highly toxic
0.1-1 mg/L
Highly toxic
1-10 mg/L
Moderately toxic
10 - 100 mg/L
Slightly toxic
>100 mg/L
Practically non-toxic
77
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4.1.1 Toxicity to Freshwater Vertebrates (Amphibians and Fish)
Freshwater fish toxicity data were used as a surrogate for aquatic-phase amphibians to assess
potential direct effects to amphibians that may serve as prey of the CRLF. Effects to freshwater fish
resulting from exposure to mancozeb or maneb are also assessed as potential prey for the CRLF. As
discussed in Section 2.5.3, over 50% of the prey mass of the large adult terrestrial-phase CRLF may
consist of vertebrates such as mice, frogs, and fish (Hayes and Tennant, 1985).
4.1.1.1 Aquatic-Phase Amphibians: Acute Exposure (Mortality) Studies
Available acute toxicity data indicate that mancozeb is moderately to highly toxic to the tested fish
species. A static acute toxicity test (MRID # 40118502) revealed that the rainbow trout was the
most sensitive of the fish species tested, with an LC50 of 460ppb. The other fish species tested,
bluegill sunfish, was at least 10 times less sensitive (LC50 range 1350ppb-3850ppb). Most of the
acute toxicity data indicate that maneb is highly toxic to tested fish. However, a static acute toxicity
test (MRID# 40706001) on the most sensitive species tested, rainbow trout, suggested that maneb
could be very highly toxic (LC50 42.0ppb) to freshwater fish. In this study, conducted with an end-
use product, a substantial decrease in test substance between the beginning and the end of the tests
was noted. The concentration of maneb decreased as much as 55% of the nominal at the zero hour
measurement, and the final measurements only averaged 13.1% of the nominal value (range was
9.6% to 22.5%). Because estimation of the actual exposures of the fish was not possible, EFED
based the study results on the most conservative concentration, which was the final (lowest)
measurement concentrations. The most sensitive endpoints derived from the rainbow trout tests
conducted with mancozeb and maneb were used to assess potential direct effects to the CRLF.
4.1.1.2 Aquatic-Phase Amphibians: Chronic Exposure (Growth, Reproduction) Studies
No chronic amphibian or freshwater fish toxicity data conducted with ETU (the major degradate of
mancozeb and maneb) is available to make a quantitative assessment. However, using the acute-to-
chronic ratio (ACR) approach with available ETU acute and chronic invertebrate and acute
freshwater fish toxicity data yields an estimated chronic freshwater fish NOAEC of 37.32 ppm (see
calculations below). This estimate indicates that the use of mancozeb and maneb could effect
growth and reproduction of freshwater fish at the parts per million levels. The estimated chronic
freshwater fish NOAEC was used to assess potential direct effects to the CRLF from mancozeb and
maneb use (Table 4-3 and Table 4-4).
ACR = acute invertebrate (26.9ppm)/chronic invert.(2.0ppm)=13.45
Estimated freshwater fish NOAEC = 96-hour LC50 freshwater fish (>502ppm/ACR (13.45)
= 37.32 ppm
The ETU acute LC50 value for freshwater fish was > 502ppm. For a bounding estimate of the
freshwater fish NOAEC, the maneb LC50 freshwater fish toxicity endpoint was used in the
calculations and the toxicity value was still at the parts per million levels.
Estimated freshwater fish NOAEC = 96-hour LC50 freshwater fish (,042ppm)/ACR
(13.45ppm) = 3.00 ppm
78
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Table 4-3 Chronic toxicity of ETU to freshwater invertebrates during a life-cycle toxicity test
Species
Puritv
("« a'i.)
xotix:
Qig/L)
I.OUX
(fig/L)
Endpoints Affected
Study
Classification
MRID
Water flea
Daphnia magna
96.2
2.0
4.1
Adult length, survival, no.
young/adult/day
Supplemental
45462901
Table 4-4 Acute toxicity of ETU to freshwater fish and invertebrates
Species
Purity (% a.i.)
LCS0 (ppm/a.i,)
Toxicity Category
Study Classification
mrii)
Water flea
Daphnia magna
99.6
269
Slightly toxic
Acceptable
45910302 or
4602090
Rainbow trout
99.1
>502
Practically nontoxic
Acceptable
45910401 or
46020903
A toxicity study conducted with ETU which evaluated the developmental stages of to Xenapus laevis
fSouth African clawed frog) will be used qualitatively (Table 4-5). Xenapus laevis developmental
stages were exposed to ETU via water column under static water conditions with daily renewal for 4
days. The developmental stages were from the blastulation (shortly after fertilization) to the free
swimming tadpole stage. Developmental stages were assessed for morphological developmental,
growth (length), and death during development at 0, 100, 250, 500, 750, and 100 mg/liter with 40
embryos per concentration. No adverse affects were observed at the highest concentration tested.
The reason this study can only be used on a qualitative basis is because there was no indication if the
gel was removed from the organisms during the blastulation stage; therefore, there is uncertainty
regarding the amount of test substance the organism was actually exposed to.
Table 4-5 Chronic toxicity of ETU to aquatic-p
iase amphibians
Test Species
Life Stage at
Test Start
Test
Chemical
Kndpoint
(mx a.i/L)
ECOTOX
Ref/MRID
Description
of Use in
Document
South African clawed
frog Venous leaves
4 days Post
fertilization
ETU
4 day- LOAEL = > 1000
(highest tested concentration)
90116
Qualitative
4.1.1.3 Freshwater Fish: Acute Exposure (Mortality) Studies
The most sensitive endpoints derived from the rainbow trout tests conducted with mancozeb and
maneb (LC50 460ppb and LC50 42.0ppb respectively) were used as a surrogate to aquatic-phase
amphibians to assess potential direct effects and also to assess indirect effects to the CRLF via
reduction of prey items. (See section 4.1.1.1 for more details)
4.1.1.4 Freshwater Fish: Chronic Exposure (Growth, Reproduction) Studies
The acute-to-chronic ratio (ACR) approach with available ETU acute and chronic invertebrate and
acute fish toxicity data (an estimated chronic NOAEC of 37.32 ppm) was used as a surrogate to
aquatic-phase amphibians as well as to assess indirect effects to the CRLF via reduction of prey
items associated with adverse reproductive and growth affects associated with chronic exposure to
ETU (See section 4.1.1.2 for more details).
4.1.1.5 Freshwater Vertebrates: Sub-lethal Effects
79
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In some of the acute tests, fish were observed swimming at the surface of the water. Also numerous
open literature studies have indicated thyroid related sub-lethal affects in amphibians such as
histological changes. Nevertheless, these effects are difficult to quantify because they are not clearly
tied to the assessment endpoints for the CRLF (i.e., survival, growth, and reproduction of
individuals). In addition, differences in habitat and behavior of the tested fish species compared
with the CRLF suggest that the results may not be readily extrapolated to frog. Furthermore, there is
uncertainty associated with extrapolating effects observed in the laboratory to more variable
exposures and conditions in the field. Therefore, potential sub-lethal effects on fish are evaluated
qualitatively in this assessment and are not used as part of the quantitative risk characterization
consistent with the Overview Document (U.S. EPA 2004) and the US Fish and Wildlife Service
review of EPA's methodology for assessing potential risks to listed species (USFWS/NMFS 2004).
4.1.2 Toxicity to Freshwater Invertebrates
Freshwater aquatic invertebrate toxicity data were used to assess potential indirect effects of
mancozeb and maneb to the CRLF. Effects to freshwater invertebrates resulting from exposure to
mancozeb or maneb may indirectly affect the CRLF via reduction in available food items. As
discussed in Section 2.5.3, the main food source for juvenile aquatic- and terrestrial-phase CRLFs is
thought to be aquatic and terrestrial invertebrates found along the shoreline and on the water surface,
such as larval alderflies, pillbugs, water striders, and particularly the sowbug.
A summary of available acute and chronic freshwater invertebrate data is provided below in Sections
4.1.2.1 through 4.1.2.3. (A summary of toxicity values are in Appendix D).
4.1.2.1 Freshwater Invertebrates: Acute Exposure (Mortality) Studies
Available freshwater invertebrate acute toxicity studies suggest that both mancozeb and maneb are
highly toxic to aquatic invertebrates. The only species tested for both chemicals was daphnid
{Daphnia magna). The most sensitive endpoint for mancozeb (LC50 580ppb) was determined from a
static 46 hour LC50 test. The endpoint derived from the only submitted maneb study was an EC50 of
120ppb. In this study (TEP), a substantial decrease in test substance concentration was noted
between the beginning and end of the test (final values averaged 34% of nominal), therefore, test
results were based on the most conservative concentration, which was the final measured
concentration). The most sensitive endpoints derived from the Daphnia magna test conducted with
mancozeb and maneb were used to assess potential indirect effects to the CRLF via reduction of prey
items (freshwater invertebrates).
4.1.2.2 Freshwater Invertebrates: Chronic Exposure (Growth, Reproduction) Studies
A chronic freshwater invertebrate toxicity test conducted with ETU (the major degradate of
mancozeb and maneb) adversely affected growth and reproduction of Daphnia magna at 4.1ppm
with a NOAEC of 2.0ppm. Adult length, survival, and fecundity (mean number of young per adult
per reproductive day) were significantly reduced at the 4.1ppm treatment level (Table 4-6). The
detection limit for young/adult/day was approximately 30% due to the limited number of replicates
80
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(two instead of the recommended four). The most sensitive endpoint derived from the Daphnia
magna test conducted with ETU was used to assess potential indirect effects to the CRLF via
reduction of prey items (freshwater invertebrates).
Table 4-6 Chronic toxicity of ETU to freshwater invertebrates during a li
Species
I'liritv
<"« a.).)
xoaix:
LOAICC
Endpoints A ffected
Study
Classification
mrw
Water flea
Daphnia magna
96.2
2.0
4.1
Adult length, survival, no.
young/adult/day
Supplemental
45462901
e-cycle toxicity test
4.1.3 Toxicity to Aquatic Plants
One study has been submitted for a mancozeb technical formulation using the freshwater green
algae. P. subcaptitatum (MRID 40943501). The EC50 fori5, subcaptitatum was 47.0 ppb based on
growth inhibition; the NOAEC was <22.0 ppb. Four end-use formulations with mancozeb co-
formulated with dimethomorph or dimethomorph/zoxamide using P. subcaptitatum, freshwater
diatom (Navicula pelliculosa), and freshwater blue-green algae (Anabaena flosaquae) were also
submitted. The ECsos ranged from 13.71ppb-130.0ppb. The NOAEC ranged from 2.88ppb-28.0ppb.
One study has been submitted for a maneb technical formulation using the freshwater green algae P.
subcaptitatum (MRID 40943501). The EC50 for P. subcaptitatum was 13.4 ppb based on growth
inhibition; the NOAEC was 5 ppb. Results were based on nominal concentrations, even though the
study author reported that maneb was unstable in the test media (at 120 hours it averaged 15% of the
nominal). The most sensitive endpoints derived from the P. subcaptitatum test conducted with
mancozeb Technical (EC50 47.0ppb) and maneb Technical (EC50 47.0ppb, NOAEC 5ppb) were used
to assess potential indirect effects to the aquatic phase tadpole CRLF via reduction of food source
(freshwater aquatic plants). (A summary of toxicity values are in Appendix D)
4.1.4 Freshwater Field Studies
A mesocosm study conducted with mancozeb is available (Table 4-7). This study followed the Society of
Environmental Toxicology and Chemistry (SETAC) "Guidance Document on Testing Procedures for
Pesticides in Freshwater Mesocosms" (July 1991) and employed the regression approach. Ten outdoor
fiberglass tanks (mesocosms) were used in this study - 3 controls and 7 treatment tanks. Each mesocosm was
approximately 2 m in diameter and 1.6 m deep with an approximate volume of 5 m3. The treatment tanks
received eight simulated spray drift applications of Penncozeb 80 WP (80% mancozeb a.i.) each separated by
one week. The nominal concentrations selected for each treatment tank were: 1.25, 4.0, 12.5, 40, 125, 400,
and 1250 ppb of Penncozeb 80 WP. The results were based upon nominal concentrations of the formulated
product and not measured concentrations of the actual test material in the treatment tanks.
Since the mesocosm study was conducted using non-replicated treatments, dose response values (EC20 and
EC50) were derived by employing non-linear regression analysis. The EC20 was regarded as the threshold
level, below which no ecologically relevant effects occur. The following table provides the toxicity of
Penncozeb 80 WP to various aquatic species in this study.
81
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Table 4-7 Toxicity of Penncozeb 80 WP to various aquatic species
ppb Penncozeb 80 WP)
Species
Period
Zooplankton
Daphnia magna
Application
252
408
Daphnia longispina
Application
332
398
Chvdorus sphaericus
Application
67
134
Scapholeberis mucronata
Application
188
263
Copepod nauplii
Application
29
57
Brachionus leydigi
Application
5.5
9.2
Keratella quadrata
Application
22
27
Hexarthra sp.
Application
Post-Application
12
12
12
12
Cephalodella sp.
Application
15
31
Phvtoplankton
Volvox sp.
Application
1.6
4.8
It should be noted that EPA's "Aquatic Mesocosm Tests to Support Pesticide Registrations_EPA 540/09-88-
035" (March 1988) requires three replicates per treatment level, a mesocosm size of 300 m3 in volume and
the inclusion of viable finfish in the study. These three major departures from EPA guideline requirements
are noted at this time. Despite these deficiencies, the study does provide some supplemental information for
characterizing the risk.
4.2 Toxicity of Mancozeb and Maneb to Terrestrial Organisms
Table 4-8 summarizes the most sensitive terrestrial toxicity endpoints for the CRLF, based on an
evaluation of submitted studies. A brief summary of submitted data considered relevant to this
ecological risk assessment for the CRLF is presented below. (A summary of toxicity values are in
Appendix D)
82
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Table 4-8 Terrestrial toxicity profile for mancozeb and maneb
. 1 ssessment Endpoint
Measures of Ecological Effects
MRU) or
Reference
Study
Classification
Direct toxicity to
terrestrial-phase
CRLF
Mancozeb-English sparrow {Passer domesticus) acute oral
LD50 = -1500 mg a.i./kg
00036094
Supplemental
Maneb-Northern bobwhite quail acute oral LD50 = >2,150
0657001
Acceptable
Maneb-Mallard duck (Anas platyrhynchos) subacute dietary
LC50 = >5,000 ppm
40657002
Acceptable
Mancozeb - Anas platyrhynchos chronic reproduction
NOAEC = 125.0ppm
41948401
Acceptable
Maneb - Anas platyrhynchos chronic reproduction NOAEC =
20ppm
4358650
Acceptable
Indirect toxicitv to
terrestrial-phase
CRLF (via toxicity
to prey items)
Mancozeb-Honey bee (Apis mellifra) acute contact- LD5 =
1396.2 ppm
00018842
Acceptable
Maneb - Apis mellifra acute contact- LD5= > 12.09
00036935
Acceptable
Mancozeb - Mite (Typhlodromus pyri)- Residual toxicity
LR50a = 0.011b a.i./A
45577201
Acceptable
Mancozeb laboratory rat Rattus norvegicus acute oral LD50
>5,000 mg/kg
00142522
Acceptable
Maneb - Rattus norvegicus acute oral LD50 >5,000 mg/kg
41975601
Acceptable
Mancozeb Rattus norvegicus reproductive NOAEL 120ppm
41365201
Acceptable
Maneb Rattus norvegicus reproductive NOAEL 75ppm
42049401
Supplemental
Acute toxicity to terrestrial animals is categorized using the system shown in Table 4-9 (U.S.EPA,
2004). Toxicity categories for terrestrial plants have not been defined. Based on these categories,
mancozeb is classified as slightly to practically non-toxic and maneb nontoxic to birds on an acute
oral basis. Both mancozeb and maneb are classified as practically non-toxic to mammals on an
acute exposure basis.
Table 4-9 Qualitative descriptors for avian and mammalian acute toxicity
Toxicity Category
Oral LI)so
Dietary LCW
Very highly toxic
<10 mg/kg
< 50 ppm
Highly toxic
10-50 mg/kg
50 - 500 ppm
Moderately toxic
51 - 500 mg/kg
501 - 1000 ppm
Slightly toxic
501 - 2000 mg/kg
1001 - 5000 ppm
Practically non-toxic
> 2000 mg/kg
> 5000 ppm
4.2.1 Toxicity to Birds
Acute and chronic avian toxicity data were used to assess the potential direct effects to the terrestrial
phase CRLF. (A summary of toxicity values are in Appendix D)
4.2.1.1 Birds: Acute Exposure (Mortality) Studies
Acute oral toxicity data for three avian species indicate that mancozeb is slightly to practically
nontoxic to avian species. The one avian study available for maneb indicates that maneb is
practically nontoxic on an acute oral basis. The most sensitive species for mancozeb, English
83
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sparrow, has an LD50 of ~1500mg/kg. This was an approximated LD50 value because the studies
conducted with mancozeb were multiple oral dose studies instead of the more common single oral
dose study and regurgitation made determination of toxicity dosages difficult. The acute oral study
for Northern bobwhite quail conducted with maneb used a single oral dose and the LD50 was >2,150
mg/kg. Mallard duck is the most sensitive avian species on a sub-acute dietary toxicity basis for
maneb, with an LC50 of >5,000. Based on this endpoint, maneb is practically nontoxic to birds on a
sub-acute dietary basis. Dietary testing was attempted with mancozeb on mallard ducks and
bobwhite quail; however, the birds had an aversion to the test diet and would not consume the test
material.
4.2.1.2 Birds: Chronic Exposure (Growth, Reproduction) Studies
4.2.2 Toxicity to Mammals
As discussed in Section 2.5.3, over 50% of the prey mass of the terrestrial phaseCRLF may consist
of vertebrates such as mice, frogs, and fish (Hayes and Tennant, 1985). Therefore, toxicity to
mammals is used to assess the potential for indirect effect to the CRLF as a result of effects to its
mammalian prey base.
A summary of available acute and chronic mammalian data is provided in Sections 4.2.2.1 through
4.2.2.3. (A summary of toxicity values are in Appendix D)
4.2.2.1 Mammals: Acute Exposure (Mortality) Studies
Acute oral toxicity mammalian studies with the laboratory rat were submitted for mancozeb (four
studies;Table 4-10 and maneb (one study; Table 4-11). The LD50 for all five studies was >5,000
mg/kg. Based on this endpoint, mancozeb and maneb are categorized as practically nontoxic to
mammals on an acute oral basis. In the mancozeb LD50 study (MRID # 0014522) there were ten rats
tested and all animals survived. The only clinical signs were mild constipation, tan-stained muzzles,
and brown-stained anogenital areas. In the maneb LD50 study of the ten rats tested there were three
male deaths at the 5,000 mg/kg dose and 2 male deaths at the 6060 mg/kg dose, and all of the
females survived until study termination. Clinical symptoms included lethargy, ataxia, hypothermia,
diarrhea, and staining, decreased defecation, and hair loss.
84
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Table 4-10 Mammalian acute oral toxicity for mancozeb
Species
% a.i.
LI)so (nif> a.i/k/0
Toxicity
Category)
Affected
Kndpoints
MRU) or
Accession
(AC) Number
Technical
Laboratory rat
(Rattus norvegicus)
laboratory mouse
(Mus musculus)\
80.0
>5,000 (male)
practically
nontoxic
mortality
AC259044
laboratory rat
(Rallus norvegicus)
72.6
>5.000 (male & female)
Probil slope = 4.5 (default)'
practically
nontoxic
mortality
00142522
Laboratory ral
(Rallus norvegicus)
70.0 &
75.0
>5.000
practically
nontoxic
mortality
AC254377
End-Use Formulation - Manco/cl)
Laboratory rat
(Rattus norvegicus)
36.0
>5,000 (male)
practically
nontoxic
mortality
AC238564
1 Raw data unavailable t
Table 4-11 Mamma
3 estimate slope; Used default assumption cited in Urban and Cook (1986).
ilian acute toxicity for maneb
Species
% a.i.
Test
Type
Uh»
(mga.i/ku))
Toxicity
Category)
Affected
Kndpoints
mrw
Technical
Laboratory rat
(Rallus norvegicus)
not
reported
oral - single
dose
>5,000
practically
nontoxic
mortality
41975601
Sub-chronic toxicity data are available for two mammal species for mancozeb. They indicate that
extended exposure to mancozeb via the diet at levels of 250 ppm will cause decreased serum
thyroxin levels in females and body weight decrements, changes in thyroid hormones, changes in
liver enzymes, microscopic changes in the liver and thyroids, increased absolute and relative thyroid
weights, and increased relative liver weights in males. (A summary of toxicity values are in
Appendix D)
4.2.2.2 Mammals: Chronic Exposure (Growth, Reproduction) Studies
Chronic mammalian data are available for two species for mancozeb and one species for maneb.
The most sensitive species for both chemicals is the laboratory rat, with a reproductive NOAEC of
125 ppm (mancozeb), and 75 ppm (maneb). The LOAEC of 1200ppm from the reproductive study
conducted with mancozeb was based on body weight decrements, increased relative thyroid weights,
and increased incidence of thyroid follicular cell hyperplasia (parental effects). There were no
adverse offspring effects attributed to mancozeb in this study. The developmental study conducted
with mancozeb resulted in gross developmental defects, central nervous system defects, skeletal
defects, cryptorchidism, abortions, and decreased fetal weight at a LOAEC of 500ppm and a
NOAEC of 128ppb. The LOAEL of 300 ppm (NOAEL = 75 ppm) in the reproductive study on
rats using maneb was based on slight delay in the startle response in the offspring (fetal effects) and
85
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parental effects included an increase in lung and liver weight and an increased incidence of diffuse
follicular epithelial hypertrophy/hyperplasia. The LOAEL of l,000ppm (NOAEL = 200ppm) for the
developmental rat study was based on increased post-implantation (embedding of fertilized egg in
uterine lining) loss, increased re-sorption (total and re-sorption per dam), and decreased fetal
viability. (A summary of toxicity values are in Appendix D)
4.2.2.3 Mammals - Sub-lethal effects
OPP has determined that there is sufficient evidence to group the EBDCs (mancozeb, maneb, and
metiram) based on a common mechanism for the induction of thyroid effects. Submitted and open
literature mammalian studies have noted thyroidal effects such as thyroid weight increase, follicular
cell hyperplasia, and decreased thyroid hormone levels. Nevertheless, these effects are difficult to
quantify because they are not clearly tied to the assessment endpoints for the CRLF (i.e., survival,
growth, and reproduction of individuals). In addition, differences in habitat and behavior of the
tested fish species compared with the CRLF suggest that the results may not be readily extrapolated
to frogs. Therefore, potential sub-lethal effects on fish are evaluated qualitatively in this assessment
and are not used as part of the quantitative risk characterization consistent with the Overview
Document (U.S. EPA 2004) and the US Fish and Wildlife Service review of EPA's methodology for
assessing potential risks to listed species (USFWS/NMFS 2004).
4.2.3 Toxicity to Terrestrial Invertebrates
Terrestrial invertebrates are a food source for terrestrial phase CRLF. Therefore, toxicity to
terrestrial invertebrates as a result of mancozeb and maneb use is assessed to determine whether
there may be indirect effects to the CRLF via reduction in available food.
4.2.3.1 Terrestrial Invertebrates: Acute Exposure (Mortality) Studies
The use of mancozeb and maneb on agricultural crops may result in exposure to non-target
beneficial insects, such as the honey bee. Acute contact studies suggest that mancozeb and maneb
are practically nontoxic to honey bees. The acute contact honey bee LD50 = >179 |ig/bee (converted
to 1396.2 ppm based on Mayer and Johansen, 1990) for mancozeb and LD50 = 12.09 |ig/bee
(converted to 94.30 ppm based on Mayer and Johansen, 1990) is used to assess potential indirect
effects to the terrestrial-phase CRLF. Additionally, a mite (Typhlodromus pyri) and honey bee
residue on foliage studies conducted with mancozeb was submitted. The residue concentration on
foliage causing 50% lethality was 0.01 lb ai/acre for Typhlodromus pyri and 0.27 lb ai.acre for
honeybee. (A summary of toxicity values are in Appendix D)
4.2.4 Toxicity to Terrestrial Plants
Terrestrial plant data are not available for mancozeb as a sole active ingredient in the TEP. There
are also no terrestrial plant data for maneb. Terrestrial plant data for mancozeb are based on a TEP
containing 60% mancozeb co-formulated with 9% dimethomorph. The non-target terrestrial plant
seedling emergence toxicity (Tier 1) and vegetative vigor toxicity (Tier 1) studies were conducted on
four monocot species and six dicot species, none of the species exposed displayed 25%inhibition for
the parameters tested. For seedling emergence, soybean and tomato are the most sensitive dicots
with 4% plant dry weight inhibition; onion is the most sensitive monocot with 12% dry weight
86
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inhibition when compared to the controls at the application rate of 1.38 and 0.02 lb a.i./A of
mancozeb and dimethomorph, respectively. For vegetative vigor, tomato is the most sensitive dicot
with a 6% plant dry weight inhibition, corn and onion are the most sensitive monocots with 2% plant
dry weight inhibition when compared to the controls at the application rate previously indicated.
(A summary of toxicity values are in Appendix D)
4.2.5 Terrestrial Field Studies
No field studies were submitted.
4.3 Use of Probit Slope Response Relationship to Provide Information on the
Endangered Species Levels of Concern
The Agency uses the probit dose response relationship as a tool for providing additional information
on the potential for acute direct effects to individual listed species and aquatic animals that may
indirectly affect the listed species of concern (U.S. EPA, 2004). As part of the risk characterization,
an interpretation of acute RQs for listed species is discussed. This interpretation is presented in
terms of the chance of an individual event {i.e., mortality or immobilization) should exposure at the
EEC actually occur for a species with sensitivity to mancozeb/maneb on par with the acute toxicity
endpoint selected for RQ calculation. To accomplish this interpretation, the Agency uses the slope
of the dose response relationship available from the toxicity study used to establish the acute toxicity
measures of effect for each taxonomic group that is relevant to this assessment. The individual
effects probability associated with the acute RQ is based on the mean estimate of the slope and an
assumption of a probit dose response relationship. In addition to a single effects probability estimate
based on the mean, upper and lower estimates of the effects probability are also provided to account
for variance in the slope, if available. The upper and lower bounds of the effects probability are
based on available information on the 95% confidence interval of the slope. A statement regarding
the confidence in the estimated event probabilities is also included. Studies with good probit fit
characteristics {i.e., statistically appropriate for the data set) are associated with a high degree of
confidence. Conversely, a low degree of confidence is associated with data from studies that do not
statistically support a probit dose response relationship. In addition, confidence in the data set may
be reduced by high variance in the slope (i.e., large 95% confidence intervals), despite good probit
fit characteristics. In the event that dose response information is not available to estimate a slope, a
default slope assumption of 4.5 (lower and upper bounds of 2 to 9) (Urban and Cook, 1986) is used.
Individual effect probabilities are calculated using an Excel spreadsheet tool IECV1.1 (Individual
Effect Chance Model Version 1.1) developed by the U.S. EPA, OPP, Environmental Fate and
Effects Division (June 22, 2004). The model allows for such calculations by entering the mean slope
estimate (and the 95% confidence bounds of that estimate) as the slope parameter for the
spreadsheet. In addition, the acute RQ is entered as the desired threshold. Results of the probit slope
analyses are described in Section 5.2.
87
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4.4 Incident Database Review
4.4.1 Terrestrial Incidents
No terrestrial incidents associated with mancozeb and maneb use in the United States were located.
4.4.2 Plant Incidents
There were a total of five plant incidents in the United States found in the Ecological Incident
Information System (EIIS)20 In one reported incident, a tank mixture of mancozeb and benomyl
applied to apple trees may have caused leaves and blossoms to drop from the trees. The certainty
index for this incident was possible. In a second incident there was reported possible fruit and
vegetable garden damage resulting from spray drift while neighbor's birch trees were sprayed. The
extent of damage was not reported. Chemical analysis showed a trace of applied pesticide. The
certainty index for this incident was probable. The third incident report indicated plant damage to
50 acres of a crop of ornamentals resulting from direct application of mancozeb and trifloxystrobin.
The application rate and method was not reported for mancozeb but was reported for trifloxystrobin.
The certainty index for this incident was possible for mancozeb and probable for trifloxystrobin.
Terrestrial plant data for trifloxystrobin resulted in an EC25 greater than the highest concentration
tested; therefore an assessment of risks was not possible. However, another strobilurin fungicide is
highly toxic to terrestrial plants. In a fourth incident, damage was reported to an onion field
resulting from aerial application of diazinon, metalaxyl, mancozeb, and chlorothalonil. The certainty
index for this incident was possible for all the chemicals. Terrestrial plant data for mancozeb
conducted with a TEP containing 60% mancozeb co-formulated with 9% dimethomorph does not
suggest toxicity to terrestrial plants. The non-target seedling emergence study resulted in a 12% dry
weight inhibition for onions and the non-target terrestrial plant vegetative vigor toxicity (Tier 1)
study resulted in 2% dry weight inhibition. The fifth reported incident was 46% plant damage to 240
acres of potatoes resulting from seed treatment with mancozeb and fludioxonil. The product had
been applied to seed but no mention was made of the type of damage that occurred with the plants.
The certainty index for this incident was possible for both chemicals. Terrestrial plant data for
mancozeb conducted with TEP containing 60% mancozeb co-formulated with 9% dimethomorph
does not suggest toxicity to terrestrial plants. There is no available non-target terrestrial plant data
for fludioxonil; however, there is numerous terrestrial plant incidents associated with this chemical.
More details can be found in Appendix J.
4.4.3 Aquatic Incidents
The Ecological Incident Information System (EIIS) reported mancozeb in three fish kill incidents.
One incident occurred in 1970, another in 1992 and the latest occurred in 1995. In the 1970 and
1992 incidents, mancozeb had been applied with an insecticide highly toxic to fish and, because of
sample analysis, EFED classified mancozeb as unlikely to have been responsible for these fish kills.
The third incident in 1995 involved a mancozeb accidental spill into a stream that was the source
water for a salmon hatchery which resulted in a fish kill at the salmon hatchery. Although EFED has
20 http://www.epa.gov/oppefedl/general/databasesdescription.htm#eiis')
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classified mancozeb to be a probable contributory cause to the kill; the exposure associated with
accidental spills are much higher than label use rates for mancozeb.
The Ecological Incident Information System (EIIS) reported maneb in three fish kill incidents. An
incident, occurring in August, 1973, reported by the Oregon Department of Agriculture showed
some fish in a 15 acre pond had been killed. Presumably drift from an aerial application of maneb
and endosulfan to potatoes caused the kill. No analysis of the dead fish was rovided. Both maneb
and endosulfan are very highly toxic to freshwater fish [maneb rainbow trout LC50 = 42.0 ppb and
endosulfan rainbow trout LC50 = 0.37 ppb (US EPA. 2001)] and both pesticides could have been
responsible for the fish kill, if in fact the kill was pesticide related. However, the inadequate
information provided with this reported incident and the lack of laboratory analyses makes it
difficult to determine the cause.
The second maneb related incident occurred in June, 1994 and was reported by the North Carolina
Department of Agriculture. The incident reported a fish kill in a 2.5 acre commercial fishpond
resulting from spray drift applications of maneb, trifluralin, imazaquin, pendimethalin, and acephate
aerially applied to corn and soybean fields near the pond. The analyzed samples did not confirm the
presence of maneb or the other pesticides listed. Based on the investigation and the analysis of
samples, it is unlikely that maneb contributed to this fish kill.
The third maneb related incident, occurring in August, 1994, was reported by the Maine Department
of Agriculture. In this incident roughly 10,000 newly released brook trout were killed in a pond that
borders New Brunswick, Canada and Maine. Three pesticides (maneb, esfenvalerate, and
chlorothalonil) recently applied to potatoes surrounding this pond were suspected in this fish kill.
Tissue samples of the fish confirmed the presence of all three pesticides (maneb at 169 ppb,
esfenvalerate at 4.2 ppb, and chlorothalonil at 20 ppb) in the fish. These fish samples were taken
from both the pond and brooks feeding the pond. All three of the pesticides are very highly toxic to
freshwater fish. Maneb's rainbow trout LC50 is 42.0 ppb, esfenvalerate's rainbow trout LC50 is
0.26 ppb (Hicks, L. May, 1995) and chlorothalonil's rainbow trout LC50 is 42.3 ppb (US EPA.
1998)]. The submitter of the incident report pointed out there were severe thunderstorms in the area
preceding the fish kill which suggest pesticide runoff may have been a factor in this incident. Based
on sampling evidence, EFED believes maneb may have been a contributory cause in this incident.
More details can be found in Appendix J.
89
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5 Risk Characterization
Risk characterization is the integration of the exposure and effects characterizations to determine the
likelihood of direct and indirect effects on the California Red Legged Frog from registered uses of
mancozeb and maneb. The risk characterization provides an 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," "likely to
adversely affect," or "may affect, but not likely to adversely affect") for the CRLF.
5.1 Risk Estimation
Risk is estimated by calculating the ratio of estimated exposure (EEC) to toxicity, which is referred
to as a risk quotient (RQ). Except for terrestrial insects, both an acute and chronic RQ are calculated
for animals (Table 5-1). For plants a non-listed species RQ and a listed species RQ are calculated.
The estimate of exposure is the same for both of these values, they differ in the toxicity value used
(e.g., terrestrial plants listed species RQ uses NOAEL whereas non-listed species RQ uses EC25).
The RQ is then compared to pre-established presumptive levels of concern (LOCs) for each category
evaluated (Table 5-1).
RQs were not determined for dip treatment to Capri figs, pineapples, and asparagus due to minimal
potential risks resulting from negligible exposure. The method of application itself does not result in
release to the environment and all active ingredient applied is expected to be tightly adsorbed to the
surface of the plant parts or seed pieces making it also unavailable for dissolution and transport.
Dietary exposure to residues on these items to the CRLF is highly unlikely as these are not food
items of the CRLF. Therefore, dip treatment uses are considered to have "no effect" on the CRLF
(see section 5.2.1.1).
With regard to seed treatment uses, potential aquatic risks are considered minimal based on
negligible aquatic exposure resulting from seed treatment compared to the rate of application used
for the assessed foliar treatment to the same crop. In making this comparison, mancozeb use on
grains, which is the highest lb a.i./Acre, is below concentrations with any listed acute RQ
exceedance. Therefore, these too should not exceed (see section 6.1.5.4). Potential terrestrial risks
associated with seed treatment use are also considered minimal. In the previous terrestrial risk
assessment (2005 mancozeb and maneb REDs), RQ values were calculated for numerous mancozeb
seed treatment uses. That evaluation considered seed treatment only use sites, not foliar use sites.
The results indicated that the acute risk to endangered species LOC would not be exceeded (RQs <
0.01). Although maneb also has numerous seed treatment uses, the mancozeb seed treatment uses
assessed would be protective because; 1) maneb toxicity to birds on an acute oral exposure basis is
less than mancozeb; and 2) the exposure (rates of application) from these seed treatment uses are
similar for maneb and mancozeb. Therefore, all mancozeb and maneb seed treatment uses are
considered to have "no effect" on the CRLF.
Acute avian and mammalian RQs were not determined for mancozeb and maneb uses. The acute dietary
risk to birds eating food items exposed to spray applications of mancozeb and maneb is expected to
be low based on the avian acute toxicity data. The acute dietary risk to birds from exposure to
mancozeb and maneb is low because; 1) dietary testing attempted on mallard ducks and bobwhite
90
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quail with mancozeb indicated an aversion to test diet (the birds would not consume the test
material); 2) there is low acute toxicity of mancozeb to birds in multiple dosing LD50 studies; 3)
there are no incidents showing that mancozeb or maneb have been responsible for bird kills or
poisonings; and 4) maneb (chemically related compound) is practically nontoxic to birds in dietary
LC50 testing (mallard duck LC50 >5,000 ppm and bobwhite quail LC50 >10,000 ppm). EFED
believes the acute dietary risk to mammals from exposure to mancozeb and maneb is low. The five
available mammalian acute oral toxicity studies for mancozeb (4 studies) and maneb (1 study)
resulted in LD50 >5,000. A "no effect" determination is made for survival of CRLF individuals via
direct effects on terrestrial phase adults and juveniles for all mancozeb and maneb uses.
Table 5-1 RQ calculation methodology and LOC values
Risk Presumption
HQ
LOC
Birds and Wild Mammals
Acute Risk
Dietary based: EECa (ppm b) / LC50 (ppm)
Dose based: EEC (mg/kg-bw/d) / LD50 (mg/kg-bw/dc)
0.5
Acute Listed Species
Dietary based: EEC (ppm) / LC50 (ppm)
Dose based: EEC (mg/kg-bw/d) / LD50 (mg/kg-bw/d)
0.1
Chronic Risk
Dietary based: EEC (ppm) / NOAEC (ppm)
Dose based: EEC (mg/kg-bw/d) / NOAEL (mg/kg-bw/d)
1.0
Aquatic Animals
Acute Risk
EEC (ppb) / (LC50 (ppb) or EC50 (ppb))
0.5
Acute Listed Species
EEC (ppb) / (LC50 (ppb) or EC50 (ppb))
0.05
Chronic Risk
EEC (ppb) / NOAEC (ppm)
1.0
Terrestrial Plants and Plants Inhabiting Semi-Aquatic Areas
Non-listed Species
EEC (lbs ai/A) / EC25 (lbs ai/A)
1.0
Listed Species
EEC (lbs a.i./A) / (EC05 or NOAEL (lbs a.i./A))
1.0
Aquatic Plants
Non-listed Species
EEC (ppb) / EC50 (ppb)
1.0
Listed Species
EEC (ppb) / (EC05 or NOAEC (ppb))
1.0
aEEC = estimated environmental concentration
b ppb = parts per billion
c mg/kg-bw/d = milligrams per kilogram of body weight per day
91
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5.1.1 Direct Effects to the CRLF
5.1.1.1 Aquatic-phase of the CRLF
Acute (peak) EECs of short-term constituents and chronic (60-d) EECs of long-term constituents in
surface water (Table 3.5) were used to calculate acute and chronic RQ values, respectively, for the
CRLF. For acute RQ values, where the parent material is expected to predominate short-term, the
use of mancozeb or maneb results were based on the following: 1) joint mancozeb-maneb
applications and maneb only uses the most sensitive acute fish (surrogate for CRLF) toxicity
endpoint for maneb was used; and 2) for mancozeb only uses, the most sensitive acute fish
mancozeb toxicity endpoint was used. ETU data, representative of long-term degradate constituents,
was used to calculate the chronic RQ for both mancozeb and maneb uses alone or together.
All uses except seed and dip treatment
Direct effect acute RQ values for the aquatic-phase CRLF are presented in Table 5-2 for mancozeb-
maneb joint application uses, in Table 5-3 for mancozeb alone application uses, and in Table 5-4 for
maneb alone application uses. Acute RQ values for joint mancozeb-maneb application uses except
for ornamental uses (ground cover, herbaceous, non-flowering shade trees, woody shrubs & vines)
and all maneb application only uses exceed the listed species acute LOC; however, none of the
mancozeb application only uses except Christmas tree plantations and Forestry (Douglas Fir) uses
exceed the listed species acute LOC (0.05).
Direct effect chronic RQ values for the aquatic-phase CRL are presented in Table 5-5. Based on the
projected 60-day mean aquatic ETU EEC for turf (the highest application rate) and the estimated
reproductive ETU NOAEC, none of the chronic RQs for mancozeb or maneb uses exceed the
Agency's chronic LOC of 1.0.
Table 5-2 Direct effect acute RQs for the aquatic-phase CRLF, mancozeb-maneb jointly used
Use
Peak
KKC( pph)1
Acute
RQ2
Listed Species LOC
Kxceedance?'
Corn (sweet/Pop), 3crops per year
91.78
2.19
yes
Apples
20.01
0.48
yes
Bananas
10.53
0.25
yes
Papayas
9.05
0.21
yes
Garlic
37.93
0.90
yes
Grapes
10.03
0.24
yes
Cucurbits (Cucumber, cantaloupe, casaba, crenshaw, honeydew,
muskmelon, summer squash, watermelon, winter melon
5.78
0.14
yes
Ornamentals (Nursery)
13.76
0.33
yes
Onion (Dried)
9.77
0.23
yes
Potatoes
9.36
0.22
yes
Ornamentals (Ground cover, Herbaceous, Non-flowering, Shade
trees, Woody shrubs & Vines
0.39
0.01
no
Ornamentals (Pachysandra)
4.71
0.11
yes
Ornamental Residential Turf
6.22
0.15
yes
Sugar Beet
21.27
0.51
yes
92
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Use
Peak
EEC( ppb)'
Acute
RQ2
Listed Species LOC
Exceedance?'
Tomatoes
8.86
0.21
yes
Turf (Commercial, Golf course, Industrial, Recreational, Sod farms)
92.46
2.20
yes
Turf (sod farms), 2 crops per year
111.07
2.64
yes
Grapes (Wine)
10.03
0.24
yes
1 Peak EECs are from Table 3-3 .
2Acute RQ = peak EEC/acute LC50 (Table 5-1); the acute maneb LC50 used is Rainbow trout 96-hour LC50 = 42 ppb
(MRID# 40706001)
3 For acute exposures, the listed species acute LOC is 0.05 (Table 5-1).
Table 5-3 Direct effect RQs for the aquatic-phase CRLF, mancozeb used alone
Peak
Acute
Listed Acute LOC
Use
EEC (ppb)'
RQ2
Exceedance?"
Corn (Field, Seed crop)
16.84
0.04
no
Cotton
8.25
0.02
no
Forestry (Douglas Fir)
40.55
0.09
yes
Pome fruits (Crab apple, pear, quince)
20.27
0.04
no
Plantains
10.83
0.02
no
Cucurbits (muskmelon, gourds)
11.36
0.02
no
Christmas tree plantations
32.02
0.07
yes
Shallot
11.30
0.02
no
Fennel, 2 crops per year
14.22
0.03
no
Asparagus
8.85
0.02
no
Cereal grains (Wheat, barley, oats, rye, tiiticali)
24.16
0.05
no
1 Peak EECs are from Table 3-3.
2 Acute RQ = peak EEC/acute LC50 (Table 5-1); the acute mancozeb LC50 is Rainbow trout 96-hour LC50 = 460 ppb
MRID# 40118502
3 For acute exposures, the listed species acute LOC is 0.05 (Table 5-1).
Table 5-4 Direct effect RQs for the aquatic-phase CRLF, maneb used alone
Use
Peak
EEC (ppb)'
Acute
RQ2
Listed Acute LOC
Exceedance?'
Almonds
45.62
1.09
yes
Brassica (Broccoli, Chinese cabbage, cauliflower, kohirabi) 3 crops
per year
38.09
0.90
yes
Loose leaf Chinese cabbage, 3 crops per year
63.69
1.52
yes
Kale, 3 crops per year
32.09
0.76
yes
Figs
6.71
0.16
yes
Brussels sprouts 2 crops per year
59.89
1.43
yes
Endive (Escarole) and Lettuce (leaf & head) 2 crops per year
59.48
1.42
yes
Pumpkin and Winter squash
5.78
0.14
yes
Onion (Green), 2 crops per year
17.35
0.41
yes
Beans (Dried)
10.64
0.25
yes
Pepper
13.36
0.32
yes
Eggplant
7.87
0.19
yes
93
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1 Peak EECs are from Table 3-3.
2Acute RQ = Peak EEC/ acute LC50 (Table 5-1); the acute maneb LC50 is Rainbow trout 96-hour LC50 = 42 ppb
(MRID# 40706001)
3 For acute exposures, the listed species acute LOC is 0.05 (Table 5-1).
Table 5-5 Direct effect RQs for the aquatic-phase CRLF, mancozeb and maneb all uses (highest
long-term constituent exposure concentration)
60-d
Chronic
Chronic
Use
EEC (ppb) '
RQ3
LOC Exceedance? 4
Turf (Sod farm) 2 crops per year1
23.14
<0.01
no
'The turf (sod farm) use represents the use with the highest long-term constituent exposure
2 60-d EEC is from Table 3-3
3Chronic RQ = 60-d EEC/chronic NOAEC (Table 5-1); the estimated chronic ETU freshwater fish NOAEC = 3,732
ppb (see section 4.1.1.2)
4For chronic risk, the chronic LOC is 1.0 (Table 5-1)
5.1.1.2 Terrestrial-phase of the CRLF
Chronic RQ values, based on exposure from residues on prey items, for direct dietrary effects to the
terrestrial-phase CRLF were calculated using upper-bound EECs for small and large insects. Avian
chronic toxicity data and exposure estimates served as a surrogate for the terrestrial-phase CRLF.
Appendix I contains specific dose- and dietary-based acute and chronic RQ calculations.
All uses except seed and dip treatment
The chronic RQs for direct effects to the terrestrial-phase CRLF exceed the chronic LOC of 1.0 for
all of the assessed mancozeb and maneb uses (Table 5-6).
Table 5-6 Direct effect dietary-based chronic RQs for the terrestrial-phase CRLF
Use
Rate
(lbs a.L/A)
Number of
Apps.
Minimum
Interval (Days)
Chronic RQ4
Chronic LOC
Exceedance? '
Turf1
17.4
4
1
37.62-602.00
Yes
Cucumbers1
2.4
8
1
7.16-64.41
Yes
Ornamentals(other)1
1.2
3
1
2.16-19.44
Yes
Almonds2
6.4
4
1
13.84-124.55
Yes
Beans (dried)2
1.6
6
5
4.88-43.88
Yes
Figs2
2.4
1
N/A
1.80-28.80
Yes
Shallot3
2.4
10
7
1.22-10.97
Yes
Fennel3
1.6
8
7
0.76-6.87
Yes
Grains (barley, oats, rye, triticale, and wheat)3
1.6
3
7
0.46-4.15
Yes
1 Joint Mancozeb/Maneb uses. Chronic toxicity endpoint based on maneb's mallard duck chronic reproduction NOAEC =
20 ppm (MRID # 43586502
2Maneb uses only. Chronic toxicity endpoint based on maneb's mallard duck chronic reproduction study NOAEC = 20
ppm (MRID # 43586502
3Mancozeb uses only. Chronic toxicity endpoint based on mancozeb's mallard duck chronic reproduction study NOAEC
= 125 ppm (MRID # 41948401)
4The RQ values shown as a range of values between fruits/pods/seeds/large insects-broadleaf plants/small insects.
5Chronic LOC = 1 (Table 5-1)
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5.1.2 Indirect Effects to the CRLF
5.1.2.1 Evaluation of Potential Indirect Effects via Reduction in Food Items (Freshwater Fish)
Acute (peak) EECs of short-term constituents and chronic (60-d) EECs of long-term constituents in
surface water (Table 3.5) were used to calculate acute and chronic RQ values, respectively, for
freshwater fish. For acute RQ values, where the parent material is expected to predominate short-
term, the use of mancozeb or maneb results were based on the following: 1) joint mancozeb-maneb
applications and maneb only uses the most sensitive acute fish toxicity endpoint for maneb was
used; and 2) for mancozeb only uses, the most sensitive acute fish mancozeb toxicity endpoint was
used. ETU data, representative of long-term degradate constituents, was used to calculate the
chronic RQ for both mancozeb and maneb uses alone or together.
All uses except seed and dip treatment
Indirect effect RQs for the aquatic-phase CRLF via effects to freshwater fish, which are potential
prey items, are presented in Table 5-7 for mancozeb-maneb joint application uses, in Table 5-8 for
mancozeb alone application uses, and in Table 5-9 for maneb alone application uses. Acute RQ
values for all joint mancozeb-maneb application uses on corn (sweet/Pop), garlic, ornamentals
(nursery), sugar beet, turf ( commercial, golf course, industrial, recreational, sod farms), and turf
(sod farms) and all of the maneb only application uses except figs, pumpkins, winter squash, beans,
and eggplants exceed the non-listed species freshwater fish LOC. None of the mancozeb only
application uses exceed the non-listed species freshwater fisn LOC.
Chronic RQ values for freshwater fish are presented in Table 5-10. Based on projected 60-day
aquatic ETU EECs and the estimated freshwater fish reproductive ETU NOAEC (see section (cite
Table and Section), none of the chronic RQs for mancozeb or maneb uses exceed the Agency's
chronic LOC of 1.0.
Table 5-7 Indirect effects for the aquatic-phase CRLF via acute effects on freshwater fish, joint
mancozeb-maneb application uses
Use
Peak
EEC( ppb)'
Acute
RQ2
Listed Species Acute
LOC Kxceedance? f
Sou-listed Species Acute
LOC Kxceedance? 4
Corn (sweet/Pop), 3crops per year
91.78
2.19
yes
yes
Apples
20.01
0.48
yes
no
Bananas
10.53
0.25
yes
no
Papayas
9.05
0.21
yes
no
Garlic
37.93
0.90
yes
yes
Grapes
10.03
0.24
yes
no
Cucurbits (Cucumber, cantaloupe, casaba,
crenshaw, honeydew, muskmelon, summer
squash, watermelon, winter melon
5.78
0.14
yes
no
Ornamentals (Nursery)
13.76
0.33
yes
no
Onion (Dried)
9.77
0.23
yes
no
Potatoes
9.36
0.22
yes
no
Ornamentals (Ground cover, Herbaceous,
Non-flowering, Shade trees, Woody shrubs
0.39
0.01
no
no
95
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Use
Peak
EEC(ppb)'
Acute
RQ2
Listed Species Acute
LOC Exceedauce? f
Sou-listed Species. 1 cute
LOC Kxceedauce? 4
& Vines
Ornamentals (Pachysandra)
4.71
0.11
yes
no
Ornamental Residential Turf
6.22
0.15
yes
no
Sugar Beet
21.27
0.51
yes
yes
Tomatoes
8.86
0.21
yes
no
Turf (Commercial, Golf course, Industrial,
Recreational, Sod farms)
92.46
2.20
yes
yes
Turf (sod farms), 2 crops per year
111.07
2.64
yes
yes
Grapes (Wine)
10.03
0.24
yes
no
1 Peak EECs are from Table 3-3
2Acute RQ = Peak EEC//acute LC50 (Table 5-1); the acute maneb LC50 used is Rainbow trout 96-hour LC50 = 42 ppb
(MRID# 40706001)
3 For acute exposures, the listed species acute LOC is 0.05 (Table 5-1)
4For acute exposures, the non-listed species acute LOC is 0.5 (Table 5-1)
Table 5-8 Indirect effects for the aquatic-phase CRLF via acute effects to freshwater fish, mancozeb
application only uses
Use
Peak
EEC (ppb)'
Acute
RQ2
Listed Species, 1 cute
LOC Exceedauce?
Sou-listed Species Acute
LOC Exceedauce? 4
Corn (Field, Seed crop)
16.84
0.04
no
no
Cotton
8.25
0.02
no
no
Forestry (Douglas Fir)
40.55
0.09
yes
no
Pome fruits (Crab apple, pear, quince)
20.27
0.04
no
no
Plantains
10.83
0.02
no
no
Cucurbits (muskmelon, gourds)
11.36
0.02
no
no
X-mass tree plantations
32.02
0.07
yes
no
Shallot
11.30
0.02
no
no
Fennel, 2 crops per year
14.22
0.03
no
no
Asparagus
8.85
0.02
no
no
Cereal grains (Wheat, barley, oats, rye,
tiiticali)
24.16
0.05
no
no
1 Peak EECs are from Table 3-3
2Acute RQ = acute LC50 (Table 5-1); the acute mancozeb LC50 is Rainbow trout 96-hour LC50= 460 ppb MRID#
40118502
3 For acute risks, the listed species acute LOC is 0.05 (Table 5-1)
4For acute risks, the non-listed species acute LOC is 0.50 (Table 5-1)
Table 5-9 Indirect effects for the aquatic-phase CRLF via acute effects to freshwater fish, maneb
application only uses
Use
Peak
EEC (ppb)'
Acute
RQ2
Listed Species Acute
LOC Exceedauce?
Sou-listed Species. 1 cute
LOC Exceedauce? 4
Almonds
45.62
1.09
yes
yes
Brassica (Broccoli, Chinese cabbage,
cauliflower, kohirabi) 3 crops per year
38.09
0.90
yes
yes
Loose leaf Chinese cabbage, 3 crops per year
63.69
1.52
yes
yes
Kale, 3 crops per year
32.09
0.76
yes
yes
96
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Figs
6.71
0.16
yes
no
Brussels sprouts 2 crops per year
59.89
1.43
yes
yes
Endive (Escarole) and Lettuce (leaf & head) 2
crops per year
59.48
1.42
yes
yes
Pumpkin and Winter squash
5.78
0.14
yes
no
Onion (Green), 2 crops per year
17.35
0.41
yes
no
Beans (Dried)
10.64
0.25
yes
no
Pepper
13.36
0.32
yes
no
Eggplant
7.87
0.19
yes
no
1 Peak EECs are from Table 3-3
2Acute RQ = Peak EEC/ acute LC50 (Table 5-1); the acute maneb LC50 is Rainbow trout 96-hour LC50= 42 ppb
(MRID# 40706001)
3 For acute exposures, the listed species acute LOC is 0.05 (Table 5-1)
4
For acute exposures, the non-listed species acute LOC is 0.5 (Table 5-1)
Table 5-10 Indirect effects for the aquatic-phase CRLF via chronic effects to freshwater fish, all
mancozeb and maneb uses (highest long-term constituent exposure concentration)
Use
60-d EEC (ppb)'
Chronic RQ'
Chronic LOC Exceedance? 4
Turf (sod) 2 crops per year1
23.14
<0.01
No
'The turf (sod farm) use represents the use with the highest long-term constituent exposure.
2 60-d EEC is from Table 3-3
3Chronic RQ= 60-d EEC/chronic NOAEC (Table 5-1); the estimated chronic ETU freshwater fish NOAEC =,732 ppb(
see section 4.1.1.2)
4For chronic risk, the chronic LOC is 1.0 (Table 5-1)
5.1.2.2 Evaluation of Potential Indirect Effects via Reduction in Food Items (Freshwater
Invertebrates)
Acute (peak) EECs of short-term constituents and chronic (21-d) EECs of long-term constituents in
surface water (Table 3.5) were used to calculate acute and chronic RQ values, respectively, for
freshwater invertebrates. For acute RQ values, where the parent material is expected to predominate
short-term, the use of mancozeb or maneb results were based on the following: 1) joint mancozeb-
maneb applications and maneb only uses the most sensitive acute freshwater invertebrate toxicity
endpoint for maneb was used; and 2) for mancozeb only uses, the most sensitive acute freshwater
invertebrate mancozeb toxicity endpoint was used. ETU data, representative of long-term degradate
constituents, was used to calculate the chronic RQ for both mancozeb and maneb uses alone or
together.
All uses except seed and dip treatment
Indirect effect RQs for the aquatic-phase CRLF via effects to freshwater invertebrates, which are
potential prey items, are presented in Table 5-11 for joint mancozeb-maneb application uses; in
Table 5-12 for mancozeb application alone use; and in Table 5-13 for maneb application alone uses.
None of the joint mancozeb-maneb application uses except turf (commercial, golf course, industrial,
recreational, sod farms), turf (sod farms), and corn and none of the mancozeb application only uses
97
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exceed the non-listed species acute LOC (0.50). All of the maneb application only uses exceed the
acute risk LOC of 0.50.
Chronic RQ values for freshwater invertebrates are presented in Table 5-14. Based on projected 21-
day mean aquatic ETU EEC on turf (the highest application rate use) and the estimated freshwater
invertebrate reproductive NOAEC none of the chronic RQs for mancozeb or maneb uses exceed the
chronic LOC of 1.0.
Table 5-11 Indirect effects for the aquatic-phase CRLF via acute effects to freshwater invertebrates,
joint mancozeb-maneb application uses
Use
Acute
KKC(ppb)'
Acute
RQ2
Acute Listed Species
LOC Kxceedance? f
Acute Sou-listed Species
LOC Kxceedance? 4
Corn (sweet/Pop), 3crops per year
91.78
0.76
yes
yes
Apples
20.01
0.17
yes
no
Bananas
10.53
0.09
yes
no
Papayas
9.05
0.07
yes
no
Garlic
37.93
0.32
yes
no
Grapes
10.03
0.08
yes
no
Cucurbits (Cucumber, cantaloupe, casaba,
crenshaw, honeydew, muskmelon, summer
squash, watermelon, winter melon
5.78
0.05
no
no
Ornamentals (Nursery)
13.76
0.11
yes
no
Onion (Dried)
9.77
0.08
yes
no
Potatoes
9.36
0.08
yes
no
Ornamentals (Ground cover, Herbaceous, Non-
flowering, Shade trees, Woody shrubs & Vines
0.39
<0.01
no
no
Ornamentals (Pachysandra)
4.71
0.04
no
no
Ornamental Residential Turf
6.22
0.05
no
no
Sugar Beet
21.27
0.18
yes
no
Tomatoes
8.86
0.07
yes
no
Turf (Commercial, Golf course, Industrial,
Recreational, Sod farms)
92.46
0.77
yes
yes
Turf (sod farms), 2 crops per year
111.07
0.93
yes
yes
Grapes (Wine)
10.03
0.08
yes
no
1 Peak EECs are from Table 3-3.
2Acute RQ = Peak EEC/acute EC50 (Table 5-1); the D. magna acute maneb 48-hour EC50 used is 120 ppb (MRID#
4074902)
3 For acute risk, the listed species LOC is 0.05 (Table 5-1).
4For acute risks, the non-listed species acute risk LOC is 0.5 (Table 5-1).
Table 5-12 Indirect effects for the aquatic-phase CRLF via effects to freshwater invertebrates,
mancozeb only application uses
Use
Acute
KKC(ppb)'
Acute RQ
. 1 cute Listed Species
LOC Kxceedancef
. 1 cute Sou-listed Species
LOC Kxceedance 4
Corn (Field, Seed crop)
16.84
0.03
no
no
Cotton
8.25
0.01
no
no
Forestry (Douglas Fir)
40.55
0.07
yes
no
98
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Use
Acute
EEC (ppb)'
Acute RQ2
. 1 cute Listed Species
LOC Exceedancef
. 1 cute Sou-listed Species
LOC Exceedance 4
Pome fruits (Crab apple, pear,
quince)
20.27
0.03
no
no
Plantains
10.83
0.02
no
no
Cucurbits (muskmelon, gourds)
11.36
0.02
no
no
X-mass tree plantations
32.02
0.05
no
no
Shallot
11.30
0.02
no
no
Fennel, 2 crops per year
14.22
0.02
no
no
Asparagus
8.85
0.01
no
no
Cereal grains (Wheat, barley, oats,
rye, triticali)
24.16
0.04
no
no
1 Peak EECs are from Table 3-3
2 Acute RQ = Peak EEC/acute EC50 (Table 5.1); the Daphnia magna acute mancozeb EC50= 580ppb (MRID40118503);
acute peak EECs from Table 3.5
3 For acute risks, the listed species LOC is 0.05 (Table 5.1)
4For acute risks, the non-listed species acute risk LOC is 0.5 (table 5.1)
Table 5-13 Indirect effect RQs for the aquatic-phase CRLF, via direct effects to freshwater
invertebrates, maneb application uses
Use
Acute
EEC (ppb)'
Acute
RQ2
Acute Listed Species
LOC Exceedance
Son-listed Species
LOC Exceedance 4
Almonds
45.62
0.38
yes
no
Brassica (Broccoli, Chinese cabbage, cauliflower,
kohirabi) 3 crops per year
38.09
0.32
yes
no
Loose leaf Chinese cabbage, 3 crops per year
63.69
0.53
yes
no
Kale, 3 crops per year
32.09
0.27
yes
no
figs
6.71
0.06
yes
no
Brussels sprouts 2 crops per year
59.89
0.50
no
no
Endive (Escarole) and Lettuce (leaf & head) 2
crops per year
59.48
0.50
no
no
Pumpkin and Winter squash
5.78
0.05
no
no
Onion (Green), 2 crops per year
17.35
0.15
yes
no
Beans (Dried)
10.64
0.09
yes
no
Pepper
13.36
0.11
yes
no
Eggplant
7.87
0.06
yes
no
1 Peak EECs are from Table 3-3
2Acute RQ = Peak EEC/acute EC50 (Table 5-1); the D. magna acute maneb 48-hour EC50 used is 120 ppb (MRID#
4074902)
3 For acute risk, the listed species LOC is 0.05 (Table 5-1)
4For acute risks, the non-listed species acute risk LOC is 0.5 (Table 5-1)
99
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Table 5-14 Indirect effect RQs for the aquatic-phase CRLF, via chronic effects to freshwater
invertebrates, all mancozeb and maneb uses (highest long-term constituent exposure concentration
21-d
Chronic
Chronic LOC
Use
EEC (ppb) -
RQ3
Exceedance?4
Turf (sod) 2 crops per year
33.20
0.17
no
'The turf (sod farm) use represents the use with the highest long-term constituent exposure.
221-d EEC is from Table 3-3
3Chronic RQ =21-d EEC/chronic NOAEC (Table 5-1); the Daphnia magna chronic ETU NOAEC = 200 ppb (
MRID# 46462901)
4For chronic risk, the chronic LOC is 1.0 (Table 5-1)
5.1.2.3 Evaluation of Potential Indirect Effects for the aquatic-phase CRLF via Reduction in Food
Items (freshwater aquatic plants)
Indirect effect RQs for the aquatic-phase CRLF via effects to algae, which is a food resource to pre-
metamorphs, are presented in Table 5-15 for mancozeb-maneb joint application uses; in Table 5-16
for mancozeb alone application uses; and in Table 5-17 for maneb alone application uses. Based on
the projected peak aquatic EECs and aquatic plant toxicity data, the RQs exceed the non-listed
aquatic plant species LOC of 1.0 for joint mancozeb-maneb application uses on corn (sweet/Pop),
apples, garlic, ornamentals (nursery), sugar beet, turf (commercial, golf course, industrial,
recreational, sod farms), and turf (sod farms) and all of the maneb only application uses except figs,
pumpkins, winter squash, beans, and eggplants. None of the mancozeb only application uses exceed
the non-listed species aquatic plant LOC.
Table 5-15 Indirect effects for the aquatic-phase CRLF via effects to freshwater aquatic plants, joint
mancozeb-maneb application uses
Use
Peak
EEC (ppb)1
Plant RQ2
Non-listed species LOC
Exceedance?3
Corn (sweet/Pop), 3crops per year
91.78
6.85
yes
Apples
20.01
1.49
yes
Bananas
10.53
0.79
no
Papayas
9.05
0.68
no
Garlic
37.93
2.83
yes
Grapes
10.03
0.75
no
Cucurbits (Cucumber, cantaloupe, casaba, crenshaw,
honeydew, summer squash, watermelon, winter melon
5.78
0.43
no
Ornamentals (Nursery)
13.76
1.03
yes
Onion (Dried)
9.77
0.73
no
Potatoes
9.36
0.70
no
Ornamentals (Ground cover, Herbaceous, Non-flowering,
Shade trees, Woody shrubs & Vines
0.39
0.03
no
Ornamentals (Pachysandra)
4.71
0.35
no
Ornamental Residential Turf
6.22
0.46
no
Sugar Beet
21.27
1.58
yes
Tomatoes
8.86
0.66
no
100
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Turf (Commercial, Golf course, Industrial, Recreational,
Sod farms)
92.46
6.90
yes
Turf (sod farms), 2 crops per year
111.07
8.29
yes
Grapes (Wine)
10.03
0.75
no
1 Peak EECs are from Table 3-3
2 Plant RQ = peak EEC/aquatic plant EC50; used freshwater green algae (P. subcaptitatum) EC50 =
40943501) (maneb value)
3 For aquatic plant exposures, the non-listed species LOC is 1 (Table 5-1
13.4 ppb (MRID#
Table 5-16 Indirect effects for the aquatic-phase CRLF via effects to freshwater aquatic plants,
mancozeb only application uses
Use
Peak EEC (ppbf
Plant RQ4
Son-listed species LOC Exceedance'F
Corn (Field, Seed crop)
16.84
0.36
no
Cotton
8.25
0.18
no
Forestry (Douglas Fir)
40.55
0.86
no
Pome fruits (Crab apple, pear, quince)
20.27
0.43
no
Plantains
10.83
0.23
no
Cucurbits (muskmelon, gourds)
11.36
0.24
no
X-mass tree plantations
32.02
0.68
no
Shallot
11.30
0.24
no
Fennel, 2 crops per year
14.22
0.30
no
Asparagus
8.85
0.32
no
Cereal grains (Wheat, barley, oats, rye,
triticali)
24.16
0.51
no
1 Peak EECs are from Table 3-3
3Non-listed aquatic plant species RQ = peak EEC/aquatic plant EC50; used freshwater green algae (P. subcaptitatum)
EC50= 47.0 ppb (MRID# 43664701)
4For aquatic plant exposures, the non-listed species risk LOC is 1.0 (Table 5-1)
Table 5-17 Indirect effects for the aquatic-phase CRLF via effects to freshwater aquatic plants,
maneb only application uses
Use
EEC
(ppb)'
Plant RQ:
Non-listed Species
LOC Exceedance ? 4
Almonds
45.62
3.40
yes
Brassica (Broccoli, Chinese cabbage, cauliflower, kohirabi) 3 crops
per year
38.09
2.84
yes
Loose leaf Chinese cabbage, 3 crops per year
63.69
4.47
yes
Kale, 3 crops per year
32.09
2.39
yes
figs
6.71
0.54
no
Brussels sprouts 2 crops per year
59.89
4.47
yes
Endive (Escarole) and Lettuce (leaf & head) 2 crops per year
59.48
4.33
yes
Pumpkin and Winter squash
5.78
0.43
no
Onion (Green), 2 crops per year
17.35
1.29
yes
Beans (Dried)
10.64
0.79
no
Pepper
13.36
1.00
yes
Eggplant
7.87
0.59
no
101
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Use
EEC
(ppb)1
Plant RQ
Non-listed Species
LOC Exceedance ? 4
1 Peak EECs are from Table 3-3
2Non-listed species plant RQ = peak EEC/aquatic plant EC50; used
freshwater green algae (P. subcaptitatum) EC50= 13.4 ppb (MRID#
40943501) (maneb value)
3 For aquatic plant exposures, the non-listed and listed
species LOC is 1 (Table 5-1)
5.1.2.4 Evaluation of Potential Indirect Effects via Reduction in Food Items (Small Mammals)
Small mammals are potential prey items for the terrestrial-phase CRLF. Chronic RQ values, based
on exposure from dietary residues, for effects to small mammals were calculated using upper-bound
EECs for dietary items and mammalian chronic toxicity data. Appendix I contains specific dietary-
based chronic RQ calculations.
All uses except seed and dip treatment
Chronic RQs exceed the chronic LOC of 1.0 for all of the assessed mancozeb and maneb uses (Table
5-18)
Table 5-18 Indirect effects for the terrestrial-phase CRLF via dietary-based exposure effects to
mammals
Rate(lhs
Number of
Minimum
Chronic LOC
Use
a.iJA)
Applications
Interval (Days)
Chronic RQs4
Exceedance? '
Turf1
17.4
4
1
8.86-637.73
Yes
Cucumbers1
2.4
8
1
1.91-121.29
Yes
Ornamentals(other)1
1.2
3
1
0.58-36.61
Yes
Almonds2
6.4
4
1
3.69-234.57
Yes
Beans (dried)2
1.6
6
5
1.30-82.64
Yes
Figs2
2.4
1
N/A
0.42-30.51
Yes
Shallot3
2.4
10
7
1.27-80.70
Yes
Fennel3
1.6
8
7
0.80-50.54
Yes
Grains (barley, oats, rye, triticale, and wheat)3
1.6
3
7
7 - 1002
Yes
1 Joint Mancozeb-Maneb application uses. Used chronic toxicity endpoint based on lab rat reproduction study - NOAEC =
75 ppm (MRID # 42049401) conducted with maneb
2Maneb uses only. Chronic toxicity endpoint based on lab rat reproduction study - NOAEC = 75ppm (MRID #
4204940lconducted with maneb
3Mancozeb uses only. Chronic toxicity endpoint based on lab rat reproduction study mallard duck chronic reproduction
study NOAEC =120ppm (MRID #41365201)
4Since the EECs are estimated for several scenarios (e.g., short grass, tall grass, broadleaf plants, seeds, etc.), the RQs are
shown as a range of values. For details, see Appendix I
5Chronic risk LOC = 1
102
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5.1.2.5 Evaluation of Potential Indirect Effects via Reduction in Food Items (Terrestrial
Invertebrates)
Indirect effects to the CRLF as a result of effects to terrestrial invertebrates were assessed by
comparing the expected mancozeb and maneb residues (mg/kg-insect) on small and large insects
(predicted by the T-REX model) to the acute contact toxicity information for the most sensitive
terrestrial invertebrate species tested, which was the honey bee.
All uses except seed and dip treatment
The acute contact RQs exceed the terrestrial invertebrate listed species LOC of 0.05 for all uses
except for maneb use on almonds or mancozeb use on grains for large insects (Table 5-19).
Table 5-19 Indirect effect RQs for the terrestrial-phase CRLF via direct effects to terrestrial
invertebrates
Use
Rate(l.bs
a.i./A)
No.
Apps.
Minimum
Interval (Days)
Large Insect
EEC (ppm)
Small Insect
EEC (ppm)
Large
Insect HQ
Small,
Insect RQ4
Turf1
17.4
4
1
752.50
6772.46
7.98
71.82
Cucumbers1
2.4
8
1
143.12
1288.10
1.52
13.66
Ornamentals(other)1
1.2
3
1
43.20
388.83
0.46
4.12
Almonds2
6.4
4
1
276.78
2491.02
0.025
26.41
Beans (dried)2
1.6
6
5
97.51
877.62
1.03
9.31
Figs2
2.4
1
N/A
36.00
324.00
0.38
3.44
Shallot3
2.4
10
7
152.35
1371.13
0.11
0.98
Fennel3
1.6
8
7
95.41
858.73
0.07
0.62
Grains (barley, oats, rye, triticale,
and wheat)3
1.6
3
7
57.60
518.43
0.045
0.37
1 Joint Mancozeb/Maneb uses. Based on honey bee LD50= = 12.09 |ig/bcc = 94.30 ppm (MRID# 00036935 conducted
with maneb
2Maneb uses only. Based on honey bee LD50= = 12.09 |ig/bcc = 94.30 ppm (MRID# 00036935 conducted with maneb
3Mancozeb uses only. Based on honey bee LD50= > 179 |ig/bcc = 1396.2 ppm (MRID# 45577201 conducted with
mancozeb
4 Acute listed species LOC = 0.05
5Does not exceed the cute listed species LOC = 0.05 (in bold)
5.1.3 Effects to Primary Constituent Elements of Designated Critical Habitat
5.1.3.1 Aquatic-Phase (Aquatic Breeding Habitat and Aquatic Non-Breeding Habitat)
Three of the four assessment endpoints for the aquatic-phase primary constituent elements (PCEs) of
designated critical habitat for the CRLF are related to potential effects to aquatic and/or terrestrial
plants:
• 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 CRLFs.
• Alteration in water chemistry/quality including temperature, turbidity, and oxygen content
necessary for normal growth and viability of juvenile and adult CRLFs and their food source.
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• Reduction and/or modification of aquatic-based food sources for pre-metamorphs (e.g., algae)
Affects in aquatic habitat from reduction in aquatic plants will be assessed using the risk
estimation values in section 5.1.2.3.
The remaining aquatic-phase PCE is "alteration of other chemical characteristics necessary for
normal growth and viability of CRLFs and their food source." To assess the impact of mancozeb
and maneb on this PCE, acute and chronic freshwater fish and invertebrate toxicity endpoints are
used as measures of effects. RQs for these endpoints were calculated in Sections 5.1.2.1 and 5.1.2.2.
Freshwater fish acute RQs exceed the LOC for; 1) all joint mancozeb/maneb uses except
Ornamentals (Ground cover, Herbaceous, Non-flowering, Shade trees, Woody shrubs & Vines); 2)
none of the mancozeb only uses; and 3) none of the maneb only uses except almonds, brassica, loose
leaf Chinese cabbage, kale, Brussels sprouts, lettuce and endive. Freshwater invertebrate acute RQs
exceed the LOC for;l) none of the joint mancozeb/maneb uses except turf (commercial, golf course,
industrial, recreational, sod farms), Turf (sod farms), and corn; 2) none of the mancozeb only uses; and
3) all of the maneb only uses.
5.1.3.2 Terrestrial-Phase (Upland Habitat and Dispersal Habitat)
Similar to the aquatic-phase PCEs, three of the four assessment endpoints for the terrestrial-phase
PCEs of designated critical habitat for the CRLF are related to potential effects to aquatic and/or
terrestrial plants:
• Elimination and/or disturbance of upland habitat; ability of habitat to support food source of
CRLFs: 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 provides the CRLF shelter, forage, and predator avoidance
• 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
• Alteration of chemical characteristics necessary for normal growth and viability of juvenile and
adult CRLFs and their food source.
There are no terrestrial plant toxicity data available on mancozeb as a sole active ingredient in the
TEP. There is also no terrestrial plant toxicity data for maneb. The terrestrial plant toxicity data
used in this effects determination for mancozeb are based on a TEP containing 60% mancozeb co-
formulated with 9% dimethomorph. (See Appendix D) In the seedling emergence (Tier I) and non-
target vegetative vigor studies conducted with this TEP the EC25 was higher than the highest
concentration tested, 1.38 lbs a.i./A. EECs, based on the highest application rate use (turf), were
estimated from the TerrPlant model to help determine what the toxicity concentration would need to
be to exceed the non-listed species plant LOC of 1. Details of the modeling exercise are included in
Appendix K. The EECs for spray drift alone, total (spray drift plus run-off) for dry areas, and total
for semi-aquatic areas were 0.191, 0.382, and 2.101 lbs a.i./A, respectively. The EECs associated
with the spray drift alone and dry areas are below the 1.38 lb/a.i./A; therefore, RQs would be below
1. Given the observed 12 % dry weight inhibition with the most sensitive species in the seedling
emergence study, it may not be unreasonable for some slopes to expect a 25% inhibition at the semi-
104
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aquatic EEC of 2.2 lbs a.i./A. However, this was the most sensitive species tested of 10 species.
The next highest % inhibition response was 6% in a seedling emergence test on tomatoes.
There were a total of five plant incidents in the United States found in the Ecological Incident
Information System (EIIS:
(1) A tank mixture of mancozeb and benomyl applied to apple trees may have caused leaves and
blossoms to drop from the trees. The certainty index for this incident was possible.
(2) There was a report of possible fruit and vegetable garden damage resulting from spray drift while
neighbor's birch trees were sprayed. The extent of damage was not reported. Chemical analysis
showed a trace of applied pesticide. The certainty index for this incident was probable.
(3) There was a reported plant damage incident to 50 acres of a crop of ornamentals resulting from
direct application of mancozeb and trifloxystrobin. The application rate and method was not
reported for mancozeb but was reported for trifloxystrobin. The certainty index for this incident
was possible for mancozeb and probable for trifloxystrobin. Terrestrial plant data for
trifloxystrobin resulted in an EC25 greater than the highest concentration tested; therefore an
assessment of risks was not possible. However, another strobilurin fungicide is highly toxic to
terrestrial plants.
(4) There was damage reported to an onion field resulting from aerial application of diazinon,
metalaxyl, mancozeb, and chlorothalonil. The certainty index for this incident was possible for
all the chemicals. Terrestrial plant data for mancozeb conducted with TEP containing 60%
mancozeb co-formulated with 9% dimethomorph does not suggest toxicity to terrestrial plants.
The non-target seedling emergence study resulted in a 12% dry weight inhibition for onions and
the non-target terrestrial plant vegetative vigor toxicity (Tier 1) study resulted in 2% dry weight
inhibition.
(5) There was a report of 46% plant damage to 240 acres of potatoes resulting from seed treatment
with mancozeb and fludioxonil. The product had been applied to seed but no mention was made
of the type of damage that occurred with the plants. The certainty index for this incident was
possible for both chemicals.
Terrestrial plant data for mancozeb conducted with TEP containing 60% mancozeb co-
formulated with 9% dimethomorph does not suggest toxicity to terrestrial plants. There is no
available non-target terrestrial plant data for fludioxonil; however, there a numerous terrestrial
plant incidents associated with this chemical. There are no terrestrial plant data available on
mancozeb as a sole active ingredient in the TEP. There is also no terrestrial plant data for
maneb.
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5.2 Risk Description
5.2.1 Introduction
This section covers the overall conclusions regarding risk to the CRLF and its habitat. These
conclusions are based on calculated RQs for various uses of mancozeb, maneb, and the
interchangeable use of the two EBDCs. In this respect, it is important to re-emphasize that the risk
assessment for the two EBDCs are combined in one assessment that uses a unique process to assess
risk to the CRLF. It was necessary to follow this procedure because of the nature of these EBDCs,
similarities in fate and transport properties and interdependency of regulatory decisions on their use.
The latter reason is associated with the fact that EBDCs produce a common degradate
ethylenethiourea (ETU); a human carcinogen. ETU is of human health concern and therefore it
played an important role in regulatory decisions concerning use of the EBDCs (e.g., maximum
seasonal or yearly labeled uses for mancozeb were set as maximum for EBDCs not mancozeb). As
for the fate of EBDCs parents (i.e., mancozeb and maneb), the two chemicals are highly vulnerable
to hydrolytic reactions that cause their instability (hydrolysis half-life in hours). Therefore, potential
acute and chronic aquatic exposure is associated with resultant hydrolytic products; a suite of
chemicals referred to as the EBDC complex. With time, the EBDC complex is expected to
progressively be dominated by ETU and ETU degradates. Therefore, the short-term acute aquatic
exposure is related to the freshly formed EBDC complex (modeled peak EECs of the EBDC
complex). In contrast, the long-term chronic aquatic exposure is assumed to be related to ETU (21-
and 60-day EECs of ETU); in the long-term the EBDC complex is enriched with ETU. These acute
and chronic EECs are chosen because they can be closely related to submitted measures of acute and
chronic aquatic effects (acute and chronic aquatic fresh water and invertebrates' toxicity data).
5.2.2 Effects Determination
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
mancozeb and maneb 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.
The criteria used to make determinations that the effects of an action are "not likely to adversely
affect" the CRLF include the following:
106
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• 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:
o 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.
o 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 5-20 contains summaries for the effects determinations for the CRLF. A description of the
risk and effects determination for each of the established assessment endpoints for the CRLF is
provided in the following sections. Table 5-21 summarizes the effects determinations for the critical
habitat.
Table 5-20 Effects determination summary for direct and indirect effects of mancozeb and maneb
on the CRLF
Assessment Endpoint
Effects Determination
Basis
Aquatic-Phase (Eggs, Larvae, Tadpoles, Adults)
Direct Effects of Mancozeb and Maneb on the Aquatic Phase CRLF
Survival of CRLF
individuals via direct effects
on aquatic phases. (Surrogate
Fish)
No effect
Joint Mancozeb-Maneb uses
Ornamentals (ground cover, herbaceous, non-
flowering shade trees, woody shrubs & vines)
Mancozeb onlv uses
corn, cotton; pome fruits(crab apple, pear, quince),
plantains, cucurbits (muskmelon, gourds), shallot;
fennel; asparagus; cereal grains (wheat; barley;
oats; rye; triticali)
Using the surrogate freshwater fish
toxicity data, the acute RQ does not
exceed the listed species acute LOC
of 0.05 or the chronic LOC.
Likely to Adversely Affect
Mancozeb/Maneb uses
corn (sweet and pop) apples, bananas, papayas,
garlic, grapes, cucurbits, ornaments (nursery,
pachysandra, residential turf), onion (dried),
potatoes, sugar beet tomatoes, turf, and grapes
Mancozeb onlv uses
Forestry(Douglas firs), x-mass tree plantations
Maneb onlv uses
Using the surrogate freshwater fish
toxicity data, the acute RQ
exceeded the listed species LOC of
0.05. Considering there is an
overlap between areas of the
expected adverse affect and where
the species is located and the
probability of occurrence, the effect
can not be discounted.
107
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Assessment Kndpoint
Effects Determination
Basis
almonds, brassica, kale, figs, brussels sprouts,
endive, lettuce, pumpkin, winter squash, onion
(green), beans, pepper, eggplant
No Effect
All dip and seed treatment uses
Growth and reproduction of
CRLF individuals via direct
effects on aquatic phases.
(Surrogate Fish)
No effect
All uses for mancozeb and maneb
None of the chronic RQs exceed the
chronic LOC of 1.0. Also an
amphibian study was used
qualitatively.
Reduction of Prey as Indirect Effects ofMancozeb andManeb on the Aquatic Phase CRLF
Survival of CRLF
individuals via effects to
food supply (i.e., aquatic
vertebrates and amphibians,
freshwater invertebrates,
non-vascular plants)
Freshwater vertebrates and amphibians
No effect
Mancozeb/Maneb uses
Ornamentals (ground cover, herbaceous, non-
flowering shade trees, woody shrubs & vines)
Mancozeb onlv uses
Corn (field, seed crop), cotton, forestry, pome
fruits, plantains, cucurbits, shallot, fennel,
asparagus, cereal grains
Using the freshwater fish toxicity
data, the acute RQs do not exceed
the listed species acute LOC of 0.05
or the chronic LOC.
Likely to Adversely Affect
Mancozeb/Maneb uses
Corn (sweet/Pop); turf
Using the freshwater fish toxicity
data, the acute RQs are above the
non-listed species acute LOC of 0.5
Mancozeb/Maneb uses
Apples
Using the freshwater fish toxicity
data, the acute RQ is close to (0.48)
the non-listed acute LOC of 0.5 and
the estimated reduction in
population was 19% for the most
sensitive species
Maneb onlv uses
almonds, brassica, kale, brussels sprouts, endive,
lettuce
Using the freshwater fish toxicity
data, the acute RQs are above the
non-listed species acute LOC of 0.5.
Maneb onlv uses
onion (green)
Using the freshwater fish toxicity
data, the acute RQ is between the
listed species LOC of 0.05 and the
non-listed acute LOC of 0.5, based
on the concentration-response the
estimated reduction in population
was 14% for the most sensitive
species
Not Likely to Adversely Affect
Mancozeb/Maneb and Maneb onlv uses
bananas, papayas, garlic, grapes, cucurbits,
ornaments (nursery, pachysandra, residential turf),
onion (dried), potatoes, sugar beet tomatoes, turf,
grapes, beans, pepper, eggplant
Using the freshwater fish toxicity
data, the acute RQs are below the
non-listed species acute LOC of
0.50, the estimated reduction in
population ranges from (0.4%-9%)
for the most sensitive species and
the chronic LOC is not exceeded.
Mancozeb onlv uses
X-mass tree plantations; forestry
Using the freshwater fish toxicity
data, the acute RQs are below the
non-listed species acute LOC of
0.50, the estimated reduction in
108
-------
Assessment Kndpoint
Effects Determination
Basis
population is <0.001% for the most
sensitive species and the chronic
LOC is not exceeded
No Effect
All din and seed treatment uses
e
Freshwater invertebrates
No Effect
Mancozeb/Maneb uses
Cucurbits, Ornamentals (Ground cover,
Herbaceous, Non-flowering, Shade trees, Woody
shrubs & Vines), ornamental pachysandra and
residential turf
Mancozeb onlv uses
Corn(field seed crop); cotton, pome fruits, plantain,
X-mass tree plantations, cucurbits (muskmelon,
gourds); shallot, fennel asparagus, cereal grains,
Maneb onlv uses
Endive; lettuce (leaf & Head) Pumpkin; Squash
(Winter)
Using the freshwater invertebrate
toxicity data, the acute RQs are
below the listed species acute risk
LOC of 0.05 and the chronic LOC
is not exceeded
Likely to Adversely
Mancozeb/Maneb use
Corn; turf
Maneb onlv use
Chinese loose leaf cabbage
Using freshwater invertebrate
toxicity data the acute RQ exceeds
the non-listed species acute LOC of
0.5.
No Effect
All seed and din treatment uses
Not likely to Adversely Affect
Mancozeb and maneb uses
apples, bananas, papayas, garlic, grapes, ornaments
(nursery), onion (dried), potatoes, sugar beet,
tomatoes, turf, and grapes; almonds, brassica, kale,
figs, onion (green), beans, pepper, eggplant,
forestry
Using the freshwater invertebrate
toxicity data, the acute RQs are
below the non-listed species acute
LOC of 0.50 and the estimated
reduction in population ranges
between <0.0001%-4% and the
chronic LOC is not exceeded.
Non-vascular aauatic olants
No Effect
Joint Mancozeb/Maneb use
Ornamentals (ground cover, herbaceous, non-
flowering, shade trees, woody shrubs & vines,
Pachysandra, residential turf),, Bananas, papayas,
grapes, cucurbits, onion (dried), potatoes, tomatoes
Maneb onlv uses
Figs, pumpkin, winter squash, beans eggplant
Using aquatic plant toxicity data the
RQ does not exceed the non- listed
species LOC of 1.0.
Mancozeb onlv uses
All of the uses
109
-------
Assessment Kndpoint
Effects Determination
Basis
Likely to Adversely
Joint Mancozeb/Maneb uses
corn (sweet/Pop), apples, garlic, ornamentals
(nursery),, sugar beet, and turf (commercial, golf
course, industrial, recreational, sod farms),
Maneb onlv uses
almonds, brassica, kale, Brussels sprouts, endive,
lettuce, green onion, pepper
Using the aquatic plant toxicity data
the RQs exceed the non-listed
species LOC of 1.0.
No Effect
Mancozeb and maneb uses
Seed and dip treatment
Growth, and reproduction of
CRLF individuals via effects
to food supply (i.e., aquatic
vertebrates and amphibians,
freshwater invertebrates
Freshwater aauatic vertebrates and amphibians
No Effect
All Mancozeb and Maneb uses
None of the chronic RQs exceed the
chronic LOC of 1.0
Freshwater invertebrates
No Effect
All Mancozeb and Maneb uses
None of the chronic RQs exceed the
chronic LOC of 1.0
Reduction of Habitat, Cover, and/or Primary Productivity as Indirect Effects of Mancozeb and Maneb on the Aquatic
Phase CRLF
Survival growth and
reproduction of CRLF
individuals via indirect
effects on habitat, cover,
and/or primary productivity
(i.e., aquatic plant
community)
Non-vascular plants
No Effect
Joint Mancozeb/Maneb use
Bananas, papayas, grapes, cucurbits, onion (dried),
potatoes, ornamentals (ground cover, herbaceous,
non-flowering, shade trees, woody shrubs & vines,
pachysandra, residential turf); tomatoes
Mancozeb onlv uses
All of the uses
Maneb onlv uses
Figs, pumpkin, winter squash, beans eggplant
Using aquatic plant toxicity data the
RQ does not exceed the non-listed
species LOC of 1.0.
Habitat Modification
Joint Mancozeb/Maneb uses
corn (sweet/Pop), apples, garlic, ornamentals
(nursery), sugar beet, and turf (commercial, golf
course, industrial, recreational, sod farms)
Maneb onlv uses
almonds, brassica, kale, Brussels sprouts, endive,
lettuce, green onion, pepper
Using aquatic plant toxicity data the
RQ exceeds the non-listed species
LOC of 1.0.
No Effect
Mancozeb and maneb uses
Seed and dip treatment
Reduction of Riparian Vegetation as Indirect Effects of Mancozeb and Maneb on the Aquatic Phase CRLF
Survival, growth and
reproduction of CRLF
individuals via effects to
riparian vegetation, required
to maintain acceptable water
No Effect
All mancozeb only uses.
110
Evaluation of terrestrial plant data
available on co-formulated
mancozeb TEP, estimated exposure
used to determine toxicity
concentration required to exceed
-------
Assessment Kndpoint
Effects Determination
Basis
plant LOC, and incident data.
quality and habitat in ponds
and streams comprising the
species' current range.
Habitat Modification
All joint mancozeb/maneb uses and maneb uses
except dip and seed treatments
Presume risk because of lack of
terrestrial plant data on maneb.
Terrestrial Phase (Juveniles and adults)
Survival, growth and
reproduction of CRLF
individuals via direct effects
on terrestrial phase adults
and juveniles (surrogate
birds)
No Effect
All mancozeb and maneb uses
No effect on survival was observed
at dietary residue levels greater than
5,000 ppm
Likely to Adversely Affect
Growth and Reproduction
All Mancozeb and Maneb uses except
Chronic RQs exceed the chronic
LOC of 1 for direct effects using
birds as a surrogate. There is an
overlap between areas of the
expected adverse affect and where
the species is located; therefore, the
effect can not be discounted.
No Efffect
Seed treatments; Dip treatments
Reduction of Prey as Indirect Effects ofMancozeb andManeb on the Terrestrial Phase CRLF
Survival, growth and
reproduction of CRLF
individuals via effects on
prey (i.e., terrestrial
invertebrates, small
terrestrial vertebrates,
including mammals and
terrestrial phase amphibians)
Terrestrial invertebrates
No Effect
All dip and seed treatment uses
Likely to Adversely Affect
All Mancozeb and Maneb uses except dip and seed
treatment
Acute contact RQs exceed the listed
species terrestrial invertebrate LOC
of 0.05.
No Effect
Seed treatments; Dip treatments
Terrestrial mammals
No Effect
All mancozeb and maneb uses
Likely to Adversely Affect for Growth and
Reproduction
All mancozeb and maneb uses except dip and seed
treatment
No effect on survival was observed
at dietary residue levels greater than
5,000 ppm
No Effect
Seed treatments; Dip treatments
Terrestrial ohasc amphibians
No Effect
All mancozeb and maneb uses
Likely to Adversely Affect
Growth and Reproduction
All Mancozeb and Maneb uses except dip and seed
treatments
No effect on survival was observed
at dietary residue levels greater than
5,000 ppm
Chronic RQs exceed the chronic
LOC of 1 for direct effects using
birds as a surrogate
No Effect
Seed treatments; Dip treatments
Ill
-------
Assessment Kndpoint
Effects Determination
Basis
Survival, growth, and
reproduction of CRLF
individuals via indirect
effects on habitat (i.e.,
riparian vegetation)
Terrestrial olants
Not Likely to Adversely Affect
All mancozeb only uses.
Evaluation of terrestrial plant data
available on co-formulated
mancozeb TEP, estimated exposure
used to determine toxicity
concentration required to exceed
plant LOC, and incident data.
Likely to Adversely Affect
All joint mancozeb/maneb uses and maneb uses
except dip and seed treatments
Presume risk do to lack of terrestrial
plant data on maneb.
112
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Table 5-21 Effects determination summary for the critical habitat impact analysis
Assessment Kndpoint
Effects Determination
Basis
Aquatic Phase PCEs (Aquatic Breeding Habitat and Aquatic IN
on-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 CRLFs.
Non-vascular olants
No Effect
Joint Mancozeb/Maneb use
Bananas, papayas, grapes, cucurbits, onion
(dried), potatoes, ornamentals (ground cover,
herbaceous, non-flowering, shade trees, woody
shrubs & vines, pachysandra, residential turf);
tomatoes
Mancozeb onlv uses
All of the uses
Maneb onlv uses
Figs, pumpkin, winter squash, beans eggplant
Using aquatic plant toxicity data
the RQ does not exceed the non-
listed species LOC of 1.0.
Habitat Modification
Joint Mancozeb/Maneb uses
corn (sweet/Pop), apples, garlic, ornamentals
(nursery), sugar beet, and turf (commercial, golf
course, industrial, recreational, sod farms)
Maneb onlv uses
almonds, brassica, kale, Brussels sprouts, endive,
lettuce, green onion, pepper
Using aquatic plant toxicity data
the RQ exceeds the non-listed
species LOC of 1.0.
No Effect
Mancozeb and maneb uses
Seed and dip treatment
Terrestrial olants
No Effect
All mancozeb only uses.
Evaluation of terrestrial plant data
available on co-formulated
mancozeb TEP, estimated exposure
used to determine toxicity
concentration required to exceed
plant LOC, and incident data.
Habitat Modification
All joint mancozeb/maneb uses and maneb uses
except dip and seed treatments
Presume risk because of lack of
terrestrial plant data on maneb.
Alteration in water
chemistry/quality including
temperature, turbidity, and
oxygen content necessary for
normal growth and viability of
juvenile and adult CRLFs and
their food source.21
Non-vascular aauatic olants
No Effect
Joint Mancozeb/Maneb use
Bananas, papayas, grapes, cucurbits, onion
(dried), potatoes, ornamentals (ground cover,
herbaceous, non-flowering, shade trees, woody
shrubs & vines, pachysandra, residential turf);
tomatoes
Mancozeb onlv uses
All of the uses
Maneb onlv uses
Figs, pumpkin, winter squash, beans eggplant
Using aquatic plant toxicity data
the RQ does not exceed the non-
listed species LOC of 1.0.
21
Physicochemical 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.
113
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Assessment Endpoint
Effects Determination
Basis
Habitat Modification
Joint Mancozeb/Maneb uses
corn (sweet/Pop), apples, garlic, ornamentals
(nursery), sugar beet, and turf (commercial, golf
course, industrial, recreational, sod farms)
Maneb onlv uses
almonds, brassica, kale, Brussels sprouts, endive,
lettuce, green onion, pepper
Using aquatic plant toxicity data
the RQ exceeds the non-listed
species LOC of 1.0.
No Effect
Mancozeb and maneb uses
Seed and dip treatment
Terrestrial olants
No Effect
All mancozeb only uses.
Evaluation of terrestrial plant data
available on co-formulated
mancozeb TEP, estimated exposure
used to determine toxicity
concentration required to exceed
plant LOC, and incident data.
Habitat Modification
All joint mancozeb/maneb uses and maneb uses
except seed treatment uses
Presume risk because of lack of
terrestrial plant data on maneb.
Habitat Modification -Freshwater invertebrates
No Effect
Mancozeb/Maneb uses
Cucurbits, Ornamentals (Ground cover,
Herbaceous, Non-flowering, Shade trees, Woody
shrubs & Vines), ornamental pachysandra and
residential turf
Alteration of other chemical
characteristics necessary for
normal growth and viability of
CRLFs and their food source.
Mancozeb onlv uses
Corn(field seed crop); cotton, pome fruits,
plantain, X-mass tree plantations, cucurbits
(muskmelon, gourds); shallot, fennel asparagus,
cereal grains,
Maneb onlv uses
Endive; lettuce (leaf & Head) Pumpkin; Squash
(Winter)
Using the freshwater invertebrate
toxicity data, the acute RQs are
below the listed species acute risk
LOC of 0.05 and the chronic LOC
is not exceeded
Habitat Modification
Mancozeb/Maneb use
Corn; turf
Maneb onlv use
Chinese loose leaf cabbage
Using freshwater invertebrate
toxicity data the acute RQ exceeds
the non-listed species acute LOC of
0.5.
No Effect
All seed and din treatment uses
Mancozeb and maneb uses
apples, bananas, papayas, garlic, grapes,
ornaments (nursery), onion (dried), potatoes,
sugar beet, tomatoes, turf, and grapes; almonds,
brassica, kale, figs, onion (green), beans, pepper,
eggplant, forestry
Using the freshwater invertebrate
toxicity data, the acute RQs are
below the non-listed species acute
LOC of 0.50 and the estimated
reduction in population ranges
between <0.0001%-4% and the
chronic LOC is not exceeded.
114
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Assessment Endpoint
Effects Determination
Basis
Reduction and/or modification
of aquatic-based food sources
for pre-metamorphs (e.g., algae)
Habitat modification Non-vascular aauatic olants
No Effect
Joint Mancozeb/Maneb use
Bananas, papayas, grapes, cucurbits, onion
(dried), potatoes, ornamentals (ground cover,
herbaceous, non-flowering, shade trees, woody
shrubs & vines, pachysandra, residential turf);
tomatoes
Mancozeb onlv uses
All of the uses
Maneb onlv uses
Figs, pumpkin, winter squash, beans eggplant
Using aquatic plant toxicity data
the RQ does not exceed the non-
listed species LOC of 1.0.
Habitat Modification
Joint Mancozeb/Maneb uses
corn (sweet/Pop), apples, garlic, ornamentals
(nursery), sugar beet, and turf (commercial, golf
course, industrial, recreational, sod farms)
Maneb onlv uses
almonds, brassica, kale, Brussels sprouts, endive,
lettuce, green onion, pepper
Using aquatic plant toxicity data
the RQ exceeds the non-listed
species LOC of 1.0.
No Effect
Mancozeb and maneb uses
Seed and dip treatment
Terrestrial Phase PCEs (Upland Habitat and Dispersal Habitat)
Elimination and/or disturbance
of upland habitat; ability of
habitat to support food source of
CRLFs: 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 provides the CRLF shelter,
forage, and predator avoidance
Non-vascular olants
No Effect
Joint Mancozeb/Maneb use
Bananas, papayas, grapes, cucurbits, onion
(dried), potatoes, ornamentals (ground cover,
herbaceous, non-flowering, shade trees, woody
shrubs & vines, pachysandra, residential turf);
tomatoes
Mancozeb onlv uses
All of the uses
Maneb onlv uses
Figs, pumpkin, winter squash, beans eggplant
Using aquatic plant toxicity data
the RQ does not exceed the acute
risk or listed species LOC of 1.0.
Habitat Modification
Joint Mancozeb/Maneb uses
corn (sweet/Pop), apples, garlic, ornamentals
(nursery), sugar beet, and turf (commercial, golf
course, industrial, recreational, sod farms)
Maneb onlv uses
almonds, brassica, kale, Brussels sprouts, endive,
lettuce, green onion, pepper
Using aquatic plant toxicity data
the RQ exceeds the acute risk and
listed species LOC of 1.0
No Effect
Mancozeb and maneb uses
Seed and dip treatment
Elimination and/or disturbance
of dispersal habitat: Upland or
Evaluation of terrestrial plant data
available on co-formulated
115
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Assessment Endpoint
Effects Determination
Basis
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
Terrestrial olant
No Effect
All mancozeb only uses.
mancozeb TEP, estimated exposure
used to determine toxicity
concentration required to exceed
plant LOC, and incident data.
Habitat Modification
All joint mancozeb/maneb uses and maneb uses
except dip and seed treatments
Presume risk because of lack of
terrestrial plant data on maneb.
Reduction and/or modification
of food sources for terrestrial
phase juveniles and adults
Habitat modification
Mancozeb and maneb uses pose
acute risks to prey items of the
CRLF, including freshwater fish
and invertebrates, other amphibians
and terrestrial invertebrates; and
chronic risk to prey items of the
CRLF, including small mammals,
other amphibians, and terrestrial
invertebrates.
Alteration of chemical
characteristics necessary for
normal growth and viability of
juvenile and adult CRLFs and
their food source.
Habitat modification
Mancozeb and maneb uses pose
chronic risk to prey items of the
CRLF, including small mammals,
other amphibians, and terrestrial
invertebrates... Also acute risks to
prey items of the CRLF, including
freshwater fish and invertebrates,
and terrestrial invertebrates; .Since
mancozeb and maneb pose chronic
risk to mammals, the CRLF may be
affected via alteration or reduction
of refugia in the form of small
mammal burrows.
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
species and its resources (i.e., food and habitat) are not expected to be uniform across the action
area. In fact, given the assumptions of drift and downstream transport (i.e., attenuation with
distance), pesticide exposure and associated risks to the species and its resources are expected to
decrease with increasing distance away from the treated field or site of application. Evaluation of
the implication of this non-uniform distribution of risk to the species 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 quantitative extrapolation of the present risk assessment's predictions of individual
effects to the proportion of the population extant within geographical areas where those effects
are predicted. Furthermore, such population information would allow for a more comprehensive
evaluation of the significance of potential resource impairment to individuals of the species.
• Quantitative information on prey base requirements for individual aquatic- and terrestrial-phase
frogs. While existing information provides a preliminary picture of the types of food sources
utilized by the frog, it does not establish minimal requirements to sustain healthy individuals at
116
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varying life stages. Such information could be used to establish biologically relevant thresholds
of effects on the prey base, and ultimately establish geographical limits to those effects. This
information could be used together with the density data discussed above to characterize the
likelihood of adverse effects to individuals.
• Information on population responses of prey base organisms to the pesticide. Currently,
methodologies are limited to predicting exposures and likely levels of direct mortality, growth or
reproductive impairment immediately following exposure to the pesticide. The degree to which
repeated exposure events and the inherent demographic characteristics of the prey population
play into the extent to which prey resources may recover is not predictable. An enhanced
understanding of long-term prey responses to pesticide exposure would allow for a more refined
determination of the magnitude and duration of resource impairment, and together with the
information described above, a more complete prediction of effects to individual frogs and
potential adverse modification to critical habitat.
Mancozeb and maneb use-specific direct effects determinations are summarized in Table 5-22 while
indirect effects are summarized in Table 5-23.
117
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Table 5-22 Mancozeb and maneb use-specific direct effects determinations1
Use
A quatic phase frogs
Terrestrial-phase frogs
Acute
Chronic
Acute
Chronic
"no effect" determination is made for all mancozeb and maneb dip and seec
treatment uses
Joint mancozeb/mane
) uses
Corn
LAA
NE
NE
LAA
Apples
LAA
NE
NE
LAA
Bananas
LAA
NE
NE
LAA
Papayas
LAA
NE
NE
LAA
Garlic
LAA
NE
NE
LAA
Grapes
LAA
NE
NE
LAA
Cucurbits
LAA
NE
NE
LAA
Ornamentals (Nursery)
LAA
NE
NE
LAA
Onion (Dried)
LAA
NE
NE
LAA
Potatoes
LAA
NE
NE
LAA
Ornamentals (Ground cover, Herbaceous, Non-flowering, Shade trees,
Woody shrubs & Vines
NE
NE
NE
LAA
Ornamentals (Pachysandra)
LAA
NE
NE
LAA
Ornamental Residential Turf
LAA
NE
NE
LAA
Sugar Beet
LAA
NE
NE
LAA
Tomatoes
LAA
NE
NE
LAA
Turf (Commercial, Golf course, Industrial, Recreational, Sod farms)
LAA
NE
NE
LAA
Turf (sod farms), 2 crops per year
LAA
NE
NE
LAA
Mancozeb only uses
Corn
NE
NE
NE
LAA
Cotton
NE
NE
NE
LAA
Forestry
LAA
NE
NE
LAA
Pome fruits)
NE
NE
NE
LAA
Plantains
NE
NE
NE
LAA
Cucurbits (muskmelon gourds)
NE
NE
NE
LAA
X-mass tree plantations
LAA
NE
NE
LAA
Shallot
NE
NE
NE
LAA
Fennel,
NE
NE
NE
LAA
Asparagus
NE
NE
NE
LAA
Cereal grains
NE
NE
NE
LAA
Maneb only uses
Almonds
LAA
NE
NE
LAA
Brassica
LAA
NE
NE
LAA
Loose leaf Chinese
LAA
NE
NE
LAA
Kale,
LAA
NE
NE
LAA
figs
LAA
NE
NE
LAA
Brussels sprouts
LAA
NE
NE
LAA
Endive) and Lettuce
LAA
NE
NE
LAA
Pumpkin and Winter squash
LAA
NE
NE
LAA
Onion (Green),
LAA
NE
NE
LAA
Beans (Dried)
LAA
NE
NE
LAA
Pepper
LAA
NE
NE
LAA
Eggplant
LAA
NE
NE
LAA
118
-------
Table 5-23 Mancozeb and maneb use-specific indirect effects determinations1 based on effects to
pray
Use
Algae
Aquatic Invertebrates
Terrestrial
Invertebrates
(Acute)
Aquatic phase
frogs and fish
Terrestria
frog
l-phase
TS
Small
Mammals
Acute
Chronic
Acute
Chronic
Acute
Chronic
Acute
Chronic
"no effect'1 determination is made for all mancozeb and maneb seed and dip treatment uses.
Joint mancozeb/maneb use
Corn
LAA
LAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Apples
LAA
NLAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Bananas
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Papayas
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Garlic
LAA
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Grapes
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Cucurbits
NE
NE
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Ornamentals (Nursery)
LAA
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Onion (Dried)
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Potatoes
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Ornamentals (Ground
cover. Herbaceous,
Non-flowering, Shade
trees. Woody shrubs &
Vines
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Ornamentals
(Pachy sandra)
NE
NE
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Ornamental Residential
Turf
NE
NE
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Sugar Beet
LAA
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Tomatoes
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Turf (Commercial, Golf
course. Industrial,
Recreational, Sod
farms)
LAA
LAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Turf (sod farms), 2
crops per year
LAA
LAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Mancozeb only
use
Corn
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Cotton
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Forestry
NE
NLAA
NE
LAA
NE
NE
NE
LAA
NE
LAA
Pome fruits)
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Plantains
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Cucurbits (muskmelon
gourds)
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
X-mass tree plantations
NE
NE
NE
LAA
NE
NE
LAA
NE
LAA
Shallot
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Fennel,
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Asparagus
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
Cereal grains
NE
NE
NE
LAA
NE
NE
NE
LAA
NE
LAA
119
-------
Use
Algae
Aquatic Invertebrates
Terrestrial
Invertebrates
(Acute)
Aquatic phase
frogs and fish
Terrestria
frog
l-pliase
'S
Small
Mammals
Acute
Chronic
Acute
Chronic
Acute
Chronic
Acute
Chronic
Maneb only uses
Almonds
LAA
NLAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Brassica
LAA
NLAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Loose leaf Chinese
LAA
LAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Kale,
LAA
NLAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
figs
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Brussels sprouts
LAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Endive) and Lettuce
LAA
NE
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Pumpkin and Winter
squash
NE
NE
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Onion (Green),
LAA
NLAA
NE
LAA
LAA
NE
NE
LAA
NE
LAA
Beans (Dried)
NE
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Pepper
LAA
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
Eggplant
LAA
NLAA
NE
LAA
NLAA
NE
NE
LAA
NE
LAA
' LAA = likely to adversely affect; NLAA = not likely to adversely affect; NE = no effect
5.2.3 Direct Effects
5.2.3.1 Aquatic-phase
Based on surrogate freshwater fish toxicity data, there is a potential for direct adverse effects of
aquatic-phase CRLF individuals from the following mancozeb and maneb uses in California (CA) as
a result of acute exposure: 1) joint mancozeb/maneb uses- corn (sweet and pop), apples, bananas,
papayas, garlic, grapes, cucurbits, ornaments (nursery, pachysandra, residential turf), onion (dried),
potatoes, sugar beet tomatoes, turf, and grapes; 2) mancozeb only uses- forestry (Douglas Fir) and
X-mass tree plantations; and 3) maneb only uses- almonds, brassica, kale, figs, brussels sprouts,
endive, lettuce, pumpkin, winter squash, onion (green), beans, pepper, eggplant. Therefore, there is
a potential for direct effects to aquatic-phase CRLF from some agricultural, and orchard uses of
mancozeb and maneb. When calculating the RQs for the joint mancozeb/maneb uses a conservative
assumption was made that maneb (not mancozeb) would primarily be used. Freshwater fish are
more sensitive to maneb (LC50 = 42 ppb) than mancozeb (LC50 460 ppb); therefore, if mancozeb was
primarily used many of the joint mancozeb/maneb uses would not exceed the endangered species
LOC. However, this assumption was made because the label allows for both mancozeb and maneb
to be used on a crop in a growing season.
None of the chronic RQs for mancozeb or maneb uses exceed the chronic LOC of 1.0; therefore a
"no effect" determination is made for all uses of mancozeb and maneb for growth and reproduction
of CRLF individuals via direct effects on aquatic phases. Developmental stages were assessed for
morphological developmental, growth (length), and death during development. No adverse affects
were observed at the highest concentration tested (lOOmg/liter). The reason this study can only be
used in a qualitative basis is because there was no indication if the gel was removed from the
organisms during the blastulation stage; therefore, there is uncertainty regarding the amount of test
120
-------
substance the organism was actually exposed to. In this assessment there is some uncertainty
associated with what substance the CRLF would be exposed to on a chronic basis. On a chronic
basis it would primarily be exposed to ETU and degradates; however the mancozeb/maneb short
term complex has a half life of about 4 days. Mancozeb and maneb have application intervals which
range from 4 to 14 days. Therefore, there would be some amount of exposure to the
mancozeb/maneb short term complex. Based on the surrogate freshwater fish toxicity profile,
mancozeb/maneb short term complex is more toxic on a chronic basis (2.19 ppb and 6.1 ppb
respectively in fish early life stage studies) than ETU (3,732 ppb based on acute-to-chronic ratio).
An analysis of the likelihood of individual direct mortality indicates that at the listed species LOC,
i.e., RQ=0 .05, the likelihood of individual mortality for mancozeb is 1 in 418,000,000 and 1 in 7,420
for maneb (Table 5-24). An analysis of the likelihood of individual direct mortality for the uses
listed below indicates that the likelihood of individual mortality for mancozeb/maneb joint uses is 1
in 6 -1 in 275, for mancozeb only uses is 1 in 7,701,000 - 1 in 9,880,000, and for maneb only uses is
lin 7- 1 in 119. There is a "likely to adversely affect" determination made for the mancozeb and
maneb uses listed below for survival of CRLF individuals via direct effects on aquatic phases. The
adverse affect can not be discounted because there is an overlap in space and time between areas of
the expected adverse affect and species location as well as the probability of occurrence.
Table 5-24 Mancozeb and maneb uses that exceed the endangered species LOC (based on
freshwater fish toxicity data)
l \C
/.<><
or HO
Likelihood of Individual
Illicit (1 in ...)
Probability oj
I'opiilalion If feet
Acute Endangered Species LOC mancozeb/maneb uses and
maneb use only1
0.05
~1 in 7.42E +03
0.01%
Corn (sweet/Pop), 3crops per year14
2.19
Apples1
0.48
~1 in 5.37E+00
19%
Bananas1
0.25
~1 in2.18E+01
5%
Papayas1
0.21
~1 in 3.46E+01
2%
Garlic14
0.90
Grapes1
0.24
~1 in 2.42E+01
4%
Cucurbits (Cucumber, cantaloupe, casaba, crenshaw, honeydew,
muskmelon, summer squash, watermelon, winter melon1
0.14
~1 in 1.19E+02
0.8%
Ornamentals (Nursery)1
0.33
~1 in 1.13E+01
9%
Onion (Dried)1
0.23
~1 in2.71E+01
Potatoe1
0.22
~1 in 3.05E+01
3%
Ornamentals (Pachysandra)1
0.11
~1 in2.75E+02
0.4%
Ornamental Residential Turf1
0.15
~1 in 9.50E+01
1%
Sugar Beet14
0.51
Tomatoes1
0.21
~1 in 3.46E+01
3%
Turf (Commercial, Golf course, Industrial, Recreational, Sod
farms)14
2.20
Turf (sod farms), 2 crops per year14
2.64
Acute Endangered Species LOC mancozeb only uses3
0.05
~1 in 4.18 E+08
Forestry3
0.09
~1 in 7.91 E+05
0.0001%
121
-------
l Ni-
UK
or HO
Likelihood oj Individual
illicit (1 in ...)
1'rohahiHly oj
I'opiilalion [/JI'd
X-mass Trees3
0.07
~1 in 9.88 E+06
0.00001%
Almonds2
1.09
Brassica (Broccoli, Chinese cabbage, cauliflower, kohirabi) 3
crops per year24
0.90
Loose leaf Chinese cabbage, 3 crops per year24
1.52
Kale, 3 crops per year24
0.76
figs2
0.16
~1 in 7.74E+00
1%
Brussels sprouts 2 crops per year24
1.43
Endive (Escarole) and Lettuce (leaf & head) 2 crops per year2
1.42
Pumpkin and Winter squash2
0.14
~1 in 1.19E+02
0.84%
Onion (Green), 2 crops per year2
0.41
~1 in 7.19E+00
14%
Beans (Dried)2
0.25
~1 in2.18E+01
4%
Pepper2
0.32
~1 in 1.21+01
8%
Eggplant2
0.19
~1 in4.6E+01
2%
1 Joint Mancozeb/Maneb uses, Rainbow trout 96-hour LC50= 42ppb (MRID# 40706001)
Probit slopes 2.8
2 Maneb only uses, Rainbow trout 96-hour LC50 = 42ppb (MRID# 40706001)
Probit slopes 2.8
3Mancozeb only uses, Rainbow trout 96-hour LC50 =460ppb MRID# 40118502, Probit slope 4.5 (default)
4 Chance of individual effect and probability of population affect were only calculated if the LOC was between 0.05-0.5
Mancozeb and maneb dip and seed treatments were previously determined to have "no effect" on the
CRLF.
The Mancozeb and maneb usage data in CA from 2002-2005 suggest that almost 98% of the total
quantity of the two EBDCs was used to treat 15 use patterns, which represents nearly 98% of the
total treated acreage. Based on the assessed potential for direct adverse effects of aquatic-phase
CRLF individuals, these uses are "likely to adversely affect" CRLF. The usage data also indicates
that approximately Ms of the total amounts of the two EBDCs used was mancozeb and that this
quantity of mancozeb was used to treat nearly V3 (29%) of the total area treated. As described below,
nearly 99% of the amount used and total acres treated with mancozeb and maneb represent their top
10 uses, only differing by the percentage treated.
Applied mancozeb (a total of 483,302 lbs) distributed as follows: grapes (22%); onions (13%),
turf/sod (13%>); tomatoes (12%); potatoes (12%); landscaping (11%); pears (6%); nursery plants
(5%); apples (4%); and wheat (1%). In terms of total acreage treated (257,258 Acres): grapes (29%);
potatoes (19%>); tomatoes (19%); onions (14%); nursery plants (9%); pears (4%); apples (3%);
turf/sod (2%) and wheat (1%); with no acreage reported for landscaping.
Applied maneb (a total of 985,311 lbs): lettuce (52%); walnuts (25%), almonds (11%); onion (4%);
tomatoes (3%); cole crops (2%); and potatoes, turf/sod/nursery and dried beans (4% total, 1% each).
In terms of total acreage treated (634,506 Acres): lettuce (59%); walnuts (23%), almonds (6%);
onion (3%); tomatoes (4%); cole crops (2%); and potatoes, turf/sod/nursery and dried beans (4%
total, 1%) each).
122
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5.2.3.2 Terrestrial-phase
Based on the T-REX modeled dietary exposures and the surrogate avian toxicity data, the chronic
RQs for direct effects to the terrestrial-phase CRLF exceed the chronic LOC of 1.0 for all of the
assessed mancozeb and maneb uses. Thus, a "may affect" determination is made based on chronic
impaired survival of terrestrial-phase CRLF.
Birds are currently used as surrogates for terrestrial-phase CRLF. However, amphibians are
poikilotherms (body temperature varies with environmental temperature) while birds are
homeotherms (temperature is regulated, constant, and largely independent of environmental
temperatures). Therefore, amphibians tend to have much lower metabolic rates and lower caloric
intake requirements than birds or mammals. As a consequence, birds are likely to consume more
food than amphibians on a daily dietary intake basis, assuming similar caloric content of the food
items. Therefore, the use of avian food intake allometric equation as a surrogate to amphibians is
likely to result in an over-estimation of exposure and risk for reptiles and terrestrial-phase
amphibians. Therefore, T-REX (version 1.3.1) has been altered to the T-HERPS model, which
allows for an estimation of food intake for poikilotherms using the same basic procedure as T-REX
to estimate avian food intake.
In order to explore influences of amphibian-specific food intake equations on dietary-based
exposures of the terrestrial-phase CRLF to mancozeb and maneb, T-HERPS was used. Also to
provide bounding estimates the same crops and application rates assessed in T-REX was used for T-
HERPS. All of the assessed mancozeb and maneb uses exceed the chronic LOC of 1 and a "likely
to adversely affect" determination is made based on chronic impaired survival of terrestrial-phase
CRLF. However, as indicated in Table 5-25, there are a few uses in which some of the food items
do not exceed the chronic level of concern. For example; for high exposure mancozeb uses
(represented by the shallot use), the chronic risk associated with small insectivore and terrestrial
phase amphibians does not exceed the LOC and chronic risks associated with fruits/pods/seeds/large
insects, small insectivore and terrestrial phase amphibians as food items for the medium and low
exposure mancozeb uses (represented by the fennel and grain uses) do not exceed the LOC.
Table 5-25 Direct CRLF Effects- upper bound Kenaga chronic terrestrial Herpetofauna RQs (from
T-HERPS)
Use
Hroadleaf
Plants/
Small Insects
m
Fruits/Pods/
Seeds/
Large Insects
HQ
Small
Herbivore
Mammals
RQ
Small
Insectivore
Mammal
RQ
Small
Terrestrial Phase
Amphibians
RQ4
Turf1
338.62
37.62
396.68
24.79
11.75
Cucumbers1
64.41
7.16
75.45
4.72
2.24
Ornamentals(other)1
19.44
2.16
22.77
1.42
0.674
Almonds2
124.55
13.84
145.91
9.12
4.32
Beans (dried)2
43.88
4.88
51.40
3.21
1.52
Figs2
19.44
2.16
22.77
1.42
0.674
Shallot3
10.97
1.22
12.85
0.804
0.384
Fennel3
6.87
0.76
8.05
0.504
0.24
Grains (barley, oats, rye, triticale, and wheat)3
4.15
0.46
4.86
0.304
0.144
123
-------
liroadleaf
I'riiits/I'ods/
Small
Small
Small
Plants/
Seeds/
Herbivore
Insectivore
Terrestrial Phase
Small Insects
Large Insects
Mammals
Mammal
Amphibians
lise
RQ
HQ
HQ
HQ
RQ4
1 Joint Mancozeb/Maneb uses; Chronic toxicity endpoint based on maneb's mallard duck chronic reproduction NOAEC =
20ppm (MRID # 43586502
2Maneb uses only; Chronic toxicity endpoint based on maneb's mallard duck chronic reproduction study NOAEC = 20ppm
(MRID # 43586502
3 Mancozeb uses only; Chronic toxicity endpoint based on mancozeb's mallard duck chronic reproduction study NOAEC
=125ppm (MRID # 41948401)p
4RQs that do not exceed the LOC of 1.
Acute avian RQs were not determined for mancozeb and maneb uses. EFED believes that based on
the avian acute toxicity data, which is used as a surrogate for the terrestrial-phase amphibian, there is
minimal terrestrial risk associated with all mancozeb and maneb uses. The acute dietary risk to birds
from exposure to mancozeb is low because; 1) dietary testing attempted on mallard ducks and
bobwhite quail indicated an aversion to test diet (the birds would not consume the test material); 2)
there is low acute toxicity of mancozeb to birds in multiple dosing LD50 studies; 3) there are no
incidents showing mancozeb has been responsible for bird kills or poisonings; and 4) maneb
(chemically related compound) is practically nontoxic to birds in dietary LC50 testing (mallard duck
LC50 > 5,000 ppm and bobwhite quail LC50 > 10,000 ppm). The acute dietary risk to birds eating
food items exposed to spray applications of maneb is also expected to be low. A "no effet"
determination is made for survival of CRLF individuals via direct effects on terrestrial phase adults
and juveniles for all mancozeb and maneb uses.
Acute mammalian RQs were not determined for mancozeb and maneb uses. Chronic terrestrial risks
drive this assessment and the acute endpoints are not definitive. Also, EFED believes the acute
dietary risk to mammals from exposure to mancozeb and maneb is low. The five available
mammalian acute oral toxicity studies for mancozeb (4 studies) and maneb (1 study) resulted in
LD50 >5,000. A "no effect" determination is made for survival of CRLF individuals via direct
effects on terrestrial phase adults and juveniles for all mancozeb and maneb uses.
Mancozeb and maneb dip and seed treatments uses have been determined to have a "no effect"
determination effect to CRLF.
5.2.4 Indirect Effects (through effects to prey)
As discussed in section 2.5.3, the diet of CRLF tadpoles is composed primarily of unicellular aquatic
plants and detritus. Based on RQs for algae (Table 5-26), applications of mancozeb and maneb are
expected to affect this food source. Therefore, indirect effects of mancozeb and maneb to CRLF
tadpoles by reductions in phytoplankton are expected based on the animal's diet during this life stage
for joint mancozeb-maneb application uses on corn (sweet/Pop), apples, garlic, ornamentals
(nursery), sugar beet, turf (commercial, golf course, industrial, recreational, sod farms), and turf (sod
farms) and all of the maneb only application uses except figs, pumpkins, winter squash, beans, and
eggplants. None of the mancozeb only application uses exceed the non-listed species aquatic plant
LOC. (see section 5.5.2.3).
124
-------
When CRLF reach juvenile and adult stages, the CRLF diet is composed of aquatic and terrestrial
invertebrates, when in aquatic and terrestrial habitats, respectively. RQ values representing acute
exposure to aquatic and terrestrial invertebrates indicate that some mancozeb and maneb uses can
potentially result in adverse effects to invertebrates.
Based on freshwater invertebrate toxicity data, there is a potential for indirect adverse effects of
aquatic-phase CRLF individuals from the following mancozeb and maneb uses in CA as a result of
acute exposure: 1) joint mancozeb/maneb uses- corn (sweet and pop) apples, bananas, papayas,
garlic, grapes, ornaments (nursery), onion (dried), potatoes, sugar beet, tomatoes, turf, and grapes; 2)
mancozeb only uses- forestry (Douglas Fir); and 3) maneb only uses- almonds, brassica, Chinese
loose leaf cabbage, kale, figs, onion (green), beans, pepper, eggplant. The joint mancozeb maneb
uses for corn and turf and the maneb use only Chinese loose leaf cabbage exceed not only the
endangered species LOC of 0.05 but also the acute risk LOC of 0.5. A "likely to adversely affect"
determination is made for these uses. An analysis of potential adverse aquatic invertebrate
population affects was assessed for joint mancozeb/maneb uses as well as maneb only uses between
the endangered species LOC and the acute risk LOC by using the Daphnia magna study with a LC50
value of 120ppb and a probit slope of 4.2. Based on this assessment, the potential reduction in
abundance of aquatic invertebrates as food for these uses would be approximately 4% at most (range
0.000006%-4%); therefore a "not likely to adversely affect" determination can be made. An analysis
was also conducted for mancozeb use on forestry with a Daphnia magna study with a LC50 value of
580ppb and a default probit slope of 4.5 which resulted in 0.00001% reduction in abundance of
aquatic invertebrates as food for this use. A "not likely to adversely affect" determination is made
for mancozeb use on forestry based on the estimated 0.00001% reduction (Table 5-26)
Based on chronic freshwater invertebrate toxicity data on ETU, none of the chronic RQs for
mancozeb or maneb uses exceed the Agency's chronic LOC of 1.00; therefore a "no effect"
determination is made for all uses of mancozeb and maneb for growth and reproduction of CRLF
individuals via direct effects on aquatic phases.
Table 5-26 Mancozeb and maneb uses that exceed the endangered species LOC (based on
freshwater invertebrate toxicity data)
Use
LOC
or RQ
Likelihood of Individual
Effect (1 in ...)
Probability
of Affect
Acute Endangered Species LOC mancozeb/maneb uses and maneb
use only1
0.05
~1 in 4.30E +07
Corn (sweet/Pop), 3crops per year14
0.76
Apples1
0.17
~1 in 1.63E+03
0.06%
Bananas1
0.09
~1 in 1.78E+05
0.0006%
Papayas, Tomatoes1
0.07
~1 in 1.62E+06
0.00006%
Garlic 1
0.32
~1 in 5.31E+01
2%
Grapes, Onion (dried), Potatoes1
0.08
~1 in 4.9E+05
0.0002%
Ornamentals (Nursery)1
0.11
~1 in 3.53E+04
0.003%
Sugar beet
0.18
~1 in 1.14E+03
0.09%
Turf (Commercial, Golf course, Industrial, Recreational, Sod
farms)14
0.77
Turf (sod farms), 2 crops per year14
0.93
125
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l \C
!.()(
or HO
Likelihood of Individual
ljjcct (1 in ...)
I'robnbilily
»/ l/A"' '
Acute Endangered Species LOC mancozeb only uses3
0.05
~1 in 4.18E+08
Forestry (Douglas Fir)3
0.07
~1 in 9.88E+06
0.00001%
Almonds2
0.38
~1 in 2.58E+01
4%
Brassica (Broccoli, Chinese cabbage, cauliflower, kohirabi) 3
crops per year2
0.32
~1 in 5.31E+01
2%
Loose leaf Chinese cabbage, 3 crops per vcar21
0.53
Kale, 3 crops per year2
0.27
~1 in 1.18E+02
0.85%
Figs, Eggplant2
0.06
~1 in 6.97E+06
0.00001%
Onion (Green), 2 crops per year2
0.15
~1 in 3.71E+03
0.03%
Beans (Dried)2
0.09
~1 inl.78E+05
0.0006%
Pepper2
0.11
~1 in 3.53E+04
0.003%
1 Joint Mancozeb/Maneb uses, Daphnia magna LC50=120ppb (MRID# 4074902); Probit slope 4.2
2 Maneb only uses, Daphnia magna LC50=120ppb (MRID# 4074902); Probit slope 4.2
3Mancozeb only uses, Daphnia magna LC50= 580ppb (MRID# 40118503), Probit slope 4.5 (default)
4 Chance of individual effect and probability of affect were only calculated if the LOC was between 0.05-0.5
Based on terrestrial invertebrate toxicity data and estimated dietary exposure, the RQs exceed the
terrestrial invertebrate LOC of 0.05 for all uses; however, the RQs are not exceeded for maneb use
on almonds or mancozeb use on grains if the large insect EEC is assumed. (See Table 5.6 in the risk
estimation section). A "likely to adversely affect" determination is made for indirect effects to
aquatic-phase CRLF via direct effects to terrestrial invertebrates for all mancozeb and maneb uses
except dip and seed treatments.
Life history data also indicate that large adult frogs consume aquatic and terrestrial vertebrates,
including: fish, frogs and mice. RQ values representing direct exposures of mancozeb and maneb to
CRLF can also be used to represent exposures of mancozeb and maneb to fish and frogs in aquatic
habitats. Based on estimated exposures resulting from use of mancozeb and maneb, acute risks to
fish and aquatic-phase frogs are possible for some uses and RQs representing exposures of
mancozeb and maneb to mice (small mammals) and terrestrial-phase frogs (that are prey) indicate
chronic risks resulting from all uses of mancozeb and maneb. Therefore, indirect effects are possible
to large CRLF adults, through decreases in prey, in both aquatic and terrestrial habitats.
Based on the freshwater fish toxicity data, there is a potential for indirect adverse effects of aquatic-
phase CRLF individuals by direct effects to freshwater fish and aquatic-phase amphibians from the
following mancozeb and maneb uses in CA as a result of acute exposure: 1) joint mancozeb/maneb
uses- corn (sweet and pop) apples, bananas, papayas, garlic, grapes, cucurbits, ornaments (nursery,
Pachysandra, residential turf), onion (dried), potatoes, sugar beet tomatoes, turf, and grapes; 2)
maneb only uses- almonds, brassica, kale, figs, brussels sprouts, endive, lettuce, pumpkin, winter
squash, onion (green), beans, pepper, eggplant. Based on ETU's estimated reproductive toxicity
value for freshwater fish (acute-to-chronic ratio), none of the chronic RQs for mancozeb or maneb
uses exceed the Agency's chronic LOC of 1.00; therefore, there is "no effect" determination for
chronic indirect effects to CRLF from direct effects to freshwater fish and aquatic-phase
invertebrates.
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The joint mancozeb maneb uses for corn and turf exceed not only the endangered species LOC of
0.05 but also the acute risk LOC of 0.5. A "likely to adversely affect" determination is made for
these uses. An analysis of potential adverse aquatic vertebrate population affects was conducted on
uses with LOCs between the endangered species and acute risk. For joint mancozeb/maneb uses and
maneb only uses a Rainbow trout study with a LC50 value of 42ppb and a probit slope of 2.8 was
used and resulted in the an estimated potential reduction in abundance of aquatic vertebrates as food
for all of the uses except apples and green onion between 0.4%-9%. The majority of the uses had
approximate reductions below 5%. Joint mancozeb/maneb use on apples and maneb use on green
onion resulted in an estimated 19% and 14% reduction respectively. A "likely to adversely affect"
determination is made for indirect effects to aquatic-phase CRLF via direct effects to aquatic
vertebrates for joint mancozeb maneb use on apples and maneb use on green onion. A "not likely to
adversely affect" determination is made for indirect effects to aquatic-phase CRLF via direct effects
to aquatic vertebrates for the other joint mancozeb maneb uses and maneb uses assessed based on
discountable affects. For mancozeb only uses forestry and X-mass trees exceeded the endangered
species LOC but not the acute risk LOC. A Rainbow trout study LC50 value of 460ppb and default
probit slope of 4.5 was used to evaluated potential adverse aquatic vertebrate population affects and
the results indicate that approximately 0.0001% (forestry) and 0.00001%) (X-mass trees) of the
aquatic vertebrate population potentially would be reduced as a result of mancozeb use. A "not
likely to adversely affect" determination is made for indirect effects to aquatic-phase CRLF via
direct effects to aquatic vertebrates for the forestry and x-mass tree mancozeb only uses based on
discountable affects. (See table)
In order to explore influences of amphibian-specific food intake equations on potential dietary based
exposures of amphibians (prey of CRLF) to mancozeb and maneb, T-HERPS is used. The Pacific
tree frog is used to represent amphibian prey species. The weight of the animal is assumed to be 2.3
g, and its diet is assumed to be composed of small and large insects. When considering chronic risk
associated with dietary-based exposures to the Pacific tree frog, the chronic risk LOC is exceeded for
frogs consuming small and large insects for all of the uses except mancozeb use on fennel and
grains. For these uses the chronic risk LOC is not exceeded for frogs consuming large insects (See
Table 5-27). A "likely to adversely affect determination is made for indirect chronic effects to
terrestrial-phase CRLF via direct effects to terrestrial vertebrates for all mancozeb and maneb uses.
Table 5-27 Indirect CRLF Effects- upper bound Kenaga chronic terrestrial Herpetofauna RQs (from
T-HERPS)
Use
Hroadleaf Plants/
Small Insects HQ
I'niits/Pods/
Seeds/Large Insects RQ
Turf1
338.62
37.62
Cucumbers1
64.41
7.16
Ornamentals(other)1
19.44
2.16
Almonds2
124.55
13.84
Beans (dried)2
43.88
4.88
Figs2
19.44
2.16
Shallot3
10.97
1.22
Fennel3
6.87
0.764
Grains (barley, oats, rye, triticale, and wheat)3
4.15
0.464
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1 Joint Mancozeb/Maneb uses. Chronic toxicity endpoint based on maneb's mallard duck chronic reproduction
NOAEC = 20ppm (MRID # 43586502
2Maneb uses only. Chronic toxicity endpoint based on maneb's mallard duck chronic reproduction study NOAEC =
20ppm (MRID # 43586502
3 Mancozeb uses only; Chronic toxicity endpoint based on mancozeb's mallard duck chronic reproduction study
NOAEC =125ppm (MRID # 41948401)
4 RQs that do not exceed the LOC of 1
5.2.5 Indirect Effects (through effects to habitat)
As discussed in section 2.5.4, the habitat of the CRLF varies during its life cycle, with the CRLF
surviving in aquatic, riparian and upland areas. Adults rely on riparian vegetation for resting,
feeding, and dispersal. Egg masses are typically attached to emergent vegetation, such as bulrushes
(Scirpus spp.) and cattails (Typha spp.) or roots and twigs, and float on or near the surface of the
water (Hayes and Miyamoto 1984).
Based on presumed affects due to lack of terrestrial plant data for maneb, there is a "likely to
adversely affect" CRLF through effects to plants composing the riparian and terrestrial habitats for
all maneb and joint mancozeb/maneb uses except seed and dip treatment uses. Based on: 1) the
results of non-target seedling emergence (Tier 1) and non-target vegetative vigor (Tier 1) studies
conducted with TEP containing 60% mancozeb co-formulated with 9% dimethomorph (the EC25 is
higher than the highest concentration tested, 1.38 lbs a.i./A); 2) an estimation of the toxicity
concentration required to exceed the plant LOC of 1 (with the use of TerrPlant to estimate the EEC,
an EC25 at 1.38 lbs a.i. concentration would be required to exceed the plant LOC); and 3) the
certainty categorization of the five reported terrestrial plants incident as only possible [4 of the
incidents were associated with exposure to other active ingredients, only one showed trace amounts
of mancozeb during chemical analysis]; a "not likely to adversely affect" determination is made for
CRLF through effects to plants composing the riparian and terrestrial habitats due to discountable
effects for mancozeb only uses.
5.2.6 Primary Constituent Elements of Designated Critical Habitat
5.2.6.1 Aquatic-Phase (Aquatic breeding habitat and aquatic non-breeding habitat)
Three of the four assessment endpoints for the aquatic-phase primary constituent elements (PCEs) of
designated critical habitat for the CRLF are related to potential effects to aquatic and/or terrestrial
plants:
• 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 CRLFs.
• Alteration in water chemistry/quality including temperature, turbidity, and oxygen content
necessary for normal growth and viability of juvenile and adult CRLFs and their food source.
• Reduction and/or modification of aquatic-based food sources for pre-metamorphs (e.g., algae)
The assessment of these endpoints is described in section 5.2.5.
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The remaining aquatic-phase PCE is "alteration of other chemical characteristics necessary for
normal growth and viability of CRLFs and their food source." To assess the impact of mancozeb
and maneb on this PCE, risk associated with acute and chronic freshwater fish and invertebrate
exposure is required. Based on the assessment for freshwater fish and invertebrates (section 5.5.2),
corn, apples, and turf of the joint mancozeb/maneb uses and all of the maneb only uses except figs,
pumpkin and winter squash, beans, pepper, seed and dip treatment, and eggplant would result in a
determination of "habitat modification".
5.2.6.2. Terrestrial-Phase (upland habitat and dispersal habitat)
Similar to the aquatic-phase PCEs, three of the four assessment endpoints for the terrestrial-phase
PCEs of designated critical habitat for the CRLF are related to potential effects to aquatic and/or
terrestrial plants:
• Elimination and/or disturbance of upland habitat; ability of habitat to support food source of
CRLFs: 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 provides the CRLF shelter, forage, and predator avoidance
• 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
• Alteration of chemical characteristics necessary for normal growth and viability of juvenile and
adult CRLFs and their food source.
The assessment of these endpoints is the same as in Section 5.2.6.1 above.
The remaining terrestrial-phase PCE is "reduction and/or modification of food sources for terrestrial
phase juveniles and adults." To assess the impact of mancozeb and maneb on this PCE, risk
associated with acute and chronic exposures to terrestrial invertebrates, mammals, and terrestrial-
phase frogs. Chronic RQs for mammals and terrestrial-phase frog's endpoints exceed the LOC for
all foliar uses; therefore, a determination of habitat modification of upland and dispersal habitat.
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6 Uncertainties
6.1 Exposure Assessment Uncertainties
6.1.1 Maximum Use Scenario
The baseline-level risk assessment focuses on characterizing potential ecological risks resulting from
a maximum use scenario, which is determined from labeled statements of maximum application rate
and number of applications with the shortest time interval between applications. The frequency at
which actual uses approach this maximum use scenario may be dependant on fungal resistance,
timing of applications, cultural practices, and market forces.
6.1.2 Joint Mancozeb/Maneb Use
When calculating the RQs for the joint mancozeb/maneb uses a conservative assumption was made
that maneb (not mancozeb) would primarily be used. Based on available toxicity data, freshwater
fish, (LC50 = 42 ppb, LC50 460 ppb for maneb and mancozeb respectively), freshwater invertebrates
(EC50 120ppb, EC50 580ppb for maneb and mancozeb respectively), and freshwater aquatic plants
(EC50 13.4ppb, EC50 47.0ppb for maneb and mancozeb respectively) are more sensitive to maneb
than mancozeb. Therefore, if mancozeb was primarily used many of the joint mancozeb/maneb uses
would not exceed the endangered species LOC labels allows for mancozeb and maneb to be used on
a single crop in a growing season.
6.1.3 Action Area Overlap with Species Range
Action area overlap with the CRLF species range is identified using GIS mapping by measuring the
overlap occurring between the established range area of the CRLF and the action area (initial area of
concern plus the maximum buffer). This overlap area (in sq km and percent), for each CRLF
recovery unit and county, is included in Appendix C, for mancozeb use, Appendix I for maneb use,
and Appendix L for the combined mancozeb and maneb use. In total, the percent use overlap is
79% for mancozeb use, 16% for maneb use, and 27% for mancozeb and maneb use.
6.1.4 CD PR Usage Information
County-level usage data were obtained from California's Department of Pesticide Regulation
Pesticide Use Reporting (CDPR PUR) database. Four years of data (2002 - 2005) were included in
this analysis because statistical methodology for identifying outliers, in terms of area treated and
pounds applied, was provided by CDPR for these years only. No methodology for removing outliers
was provided by CDPR for 2001 and earlier pesticide data; therefore, this information was not
included in the analysis because it may misrepresent actual usage patterns. CDPR PUR
documentation indicates that errors in the data may include the following: a misplaced decimal;
incorrect measures, area treated, or units; and reports of diluted pesticide concentrations. In
addition, it is possible that the data may contain reports for pesticide uses that have been cancelled.
The CPDR PUR data does not include homeowner-applied pesticides; therefore, residential uses are
not likely to be reported. As with all pesticide use data, there may be instances of misuse and
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misreporting. The Agency made use of the most current, verifiable information; in cases where
there were discrepancies, the most conservative information was used.
6.1.5 Aquatic Exposure
6.1.5.1 Models and Model Inputs
The standard ecological water body scenario (EXAMS pond) used to calculate potential aquatic
exposure to pesticides is intended to represent conservative estimates, and to avoid underestimations
of the actual exposure. The standard scenario consists of application to a 10-hectare field bordering
a 1-hectare, 2-meter deep (20,000 m3) pond with no outlet. Exposure estimates generated using the
EXAMS pond are intended to represent a wide variety of vulnerable water bodies that occur at the
top of watersheds including prairie pot holes, playa lakes, wetlands, vernal pools, man-made and
natural ponds, and intermittent and lower order streams. As a group, there are factors that make
these water bodies more or less vulnerable than the EXAMS pond. Static water bodies that have
larger ratios of pesticide-treated drainage area to water body volume would be expected to have
higher peak EECs than the EXAMS pond. These water bodies will be either smaller in size or have
larger drainage areas. Smaller water bodies have limited storage capacity and thus may overflow
and carry pesticide in the discharge, whereas the EXAMS pond has no discharge. As watershed size
increases beyond 10-hectares, it becomes increasingly unlikely that the entire watershed is planted
with a single crop that is all treated simultaneously with the pesticide. Headwater streams can also
have peak concentrations higher than the EXAMS pond, but they likely persist for only short periods
of time and are then carried and dissipated downstream.
The Agency acknowledges that there are some unique aquatic habitats that are not accurately
captured by this modeling scenario and modeling results may, therefore, under- or over-estimate
exposure, depending on a number of variables. For example, aquatic-phase CRLFs may inhabit
water bodies of different size and depth and/or are located adjacent to larger or smaller drainage
areas than the EXAMS pond. The Agency does not currently have sufficient information regarding
the hydrology of these aquatic habitats to develop a specific alternate scenario for the CRLF. As
previously discussed in Section 2.5 and ATTACHMENT 1, CRLFs prefer habitat with perennial
(present year-round) or near-perennial water and do not frequently inhabit vernal (temporary) pools
because conditions in these habitats are generally not suitable (Hayes and Jennings 1988).
Therefore, the EXAMS pond is assumed to be representative of exposure to aquatic-phase CRLFs.
In addition, the Services have agreed that the existing EXAMS pond represents the best currently
available approach for estimating aquatic exposure to pesticides (USFWS/NMFS 2004).
6.1.5.2 Long-term Chronic Exposure
There is uncertainty associated with what substance the CRLF would be exposed to on a chronic
basis. Based on fate and transport data, it is assumed that it would primarily be exposed to ETU and
degradates. Giving this assumption, two uncertainties may be identified concerning exposure to the
long-term bound residue and the short-term EBDC complex. These two uncertainties are explained
hereunder.
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(a) Exposure to the Bound Residue in Sediment
There is uncertainty regarding the risks to freshwater invertebrates from exposure to the bound
residues in sediment. The risk that might be associated with the sediment bound residue would
probably be associated with its possible conversion into ETU at low concentrations. This ETU
exposure is covered by the ETU modeling exercise. In this exercise, the application rate used
represents 100% transformation to ETU from the total amount of the applied parent. Additionally,
included in this assessment is a recently reviewed freshwater invertebrate toxicity study conducted
with ETU. The approach used in this risk assessment to address this uncertainty results generally in
an overestimation of risk.
(b) Exposure to the EBDC complex
The mancozeb and maneb short-term complex (the EBDC complex) has a half life is about 4 days
and mancozeb and maneb have application intervals which range from 4 to 14 days. The 4 day half
life and short application intervals would result in periodic pulses of the short term complex in the
aquatic media. Based on the freshwater fish early life stage studies with pulsed mancozeb or maneb,
the short term complex is more toxic on a chronic basis (2.19 ppb and 6.1 ppb respectively) than the
estimated ETU (3,732 ppb). There is uncertainty regarding what impact the toxicity associated with
exposure to the short term complex would have on the growth and reproductive effects of aquatic
organisms because, chronic exposure to the short term complex in the field would not be constant,
and there is no laboratory data which demonstrates the effect of a single pulse of the short term
complex on reproductive success. Also, the acute freshwater fish ETU toxicity value used to
estimate chronic freshwater fish toxicity was a greater than value (i.e. LC50> 502ppm), thus the
resultant chronic value will be an overestimate of risk. Therefore, the use of ETU to reflect chronic
exposure to aquatic organisms could potentially be either an over or underestimate of chronic risk.
6.1.5.3 Timing of Application
There is uncertainty in the PRZM/EXAMS application timing relative to rainfall/runoff events. An
attempt was made to model applications during the wet season (winter/early spring), but changing
application dates even within a season can result in variable EECs. Usage data suggests that
mancozeb and maneb may be used throughout the year on most crops, but the highest usage appears
to be during the early spring. To the extent that applications made in the summer are subject to less
runoff than those made during the rainy season, EECs presented in this assessment may over-predict
exposures.
For example, according to the CA crop profile for tomatoes22, typical fungicide application windows
are from March 1 to November 30 for the fresh market tomatoes crop, July 1 to October 31, and
January 1 to May 30 for the other types. Therefore, the combined application window may extend
from January 1 to November 30 with no application in April. EECs were determined for assumed
applications covering the whole application window and results are summarized in Figure 6-1.
Results show that EECs were highest for applications through the month of January (between 21 and
14 ppb), levels off between April and August (around 7 ppb) and finally increase to the 14 ppb level.
It is thus expected that higher EECs would be obtained for application during the raining season. In
22 http://pestdata.ncsu.edu/croptimelines/pdf/CAfreshtomato.PDF
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this assessment, considerations were given to available crop profiles and weather data (varies with
the location of the scenario).
28
3.5
~ EECs (ppb)
—¦—Rainfal (cm/day)
21
2.5
14
7
0.5
0
J J J J J FF F FMMMMAAAAAMMMMJ J J J J J J J JAAAASSSSOOOOONNNNDDDD
Application dates (weekly intervals)
Figure 6-1 Effect of application timing on modeled EECs for tomatoes
6.1.5.4 Multiple Cropping
Mancozeb product labels specify application rates on a per crop basis (not on a per annual basis).
Information from BEAD indicates that many crops can be grown more than one time/year in
California. Since standard PRZM scenarios consist of only one crop per year, multiple applications
were executed to represent multiple cropping. Therefore, if a pesticide is applied three times per
growing season and the crop is planted two times per year; six consecutive applications were
modeled. Additionally, all crops with multiple cropping were modeled with the first application on
January because the crop has to be planted early and this application timing results in conservative
estimates of the EECs. There is uncertainty in this approach as it is believed to be highly
conservative because it does not consider the time between the first crop and the other and multiple
cropping are usually associated with more than one crop on the same area.
6.1.5.5 Seed Treatment
The amount of mancozeb and maneb applied to seed is relatively small compared to the amount
applied to the crop later (foliar spray, if any). Therefore it is expected that environmental exposure
from seed treatment would be insignificant compared to exposure from foliar spray. However, to
reduce uncertainty that may arise from this exposure route, EECs were modeled for a selection of
crops and the results indicate insignificance except for cereal grains (peak increased by 1 ppb or by
4%; Table 6-1). In this respected it is pointed out that variation are expected to be much larger as a
result of timing of application (refer to the tomatoes example in 6.1.5.3)
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Table 6-1 Comparison between application rates and EECs for foliar spray and seed treatment (ST)
Seed Treatment(ST)
Peak EECs (ppb)
ST EECs as % of
Crop
Chemical
Rate*
Foliar Application
Seed Application
Foliar treatment EECs
Tomatoes
Mancozeb
0.03%
9.56
0.0009
0.01%
Maneb
0.03%
8.86
0.0001
0.001%
Cotton
Mancozeb
0.49%
8.25
0.1253
1.5%
Maneb
No Foliar *
No Foliar *
0.0007
No Foliar *
Corn
Mancozeb
0.50%
16.84
0.1112
0.66%
Maneb
0.83%
46.74
0.0640
0.14%
Cereals
Mancozeb
6.67%
24.16
0.9880
4.1%
Maneb
No Foliar *
No Foliar *
0.0079
No Foliar *
* ST rate= seed treatment rate as % of foliar treatment rate; No Foliar= no foliar application for this crop.
6.1.5.6 Irrigation Scenarios
Even though many agricultural practices in California rely on irrigation, non-irrigated scenarios were
used for this assessment since there is a known bug in the irrigation routines in the current version of
PRZM. EECs from irrigated scenario could be higher or lower than those predicted in this
assessment.
6.1.5.7 Exposure to Trace Elements
Degradation of mancozeb and maneb will result in the release of ions of the trace elements Mn+2 and
Zn+2 from mancozeb and Zn+2 from maneb. EECs, for these trace elements, were estimated using
amounts expected to be associated with determined EECs for the EBDC complex (20% metallic Mn
plus 2.4% metallic Zn for mancozeb and 20.6% metallic Mn for maneb). Calculated EECs for Mn
are expected to range from 0.08 to 26.4 ppb and Zn from 0.01 to 27.2 ppb. This is based on a range
of 0.39 to 132 ppb of the EBDC complex (Maximum and minimum peak EECs of 8.2 to 40.55 ppb
for mancozeb, 6.71 to 63.69 ppb for maneb, and 0.39 to 132 ppb for mancozeb/maneb). Results
indicate that these concentrations are much lower than those monitored in the natural environment
(Table 6-2).
Table 6-2 Monitored Mn and Zn concentrations in CA surface waters (USGS/NAWQA data)23
Zinc concentration in ppb
Manganese concentration in ppb
Statistics
Water
Sediment
Biota
Water
Sediment
Biota
Average
9
198
128
71
1,187
53
Minimum
0
34
17
0
520
3
Maximum
391
520
749
9,833
9,000
450
SD
23
124
132
390
1,085
96
%Dev
253%
63%
103%
551%
91%
179%
SD= Standard deviation:
rom the mean (the average); and %Dev= °/
o deviation from t
ie mean
23 http://infotrek.er.usgs.gov/traverse/f?r)=136:23:0:QUERY:NO
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6.1.5.8 Action Area
An example of an important simplifying assumption that may require future refinement is the
assumption of uniform runoff characteristics throughout a landscape. It is well documented that
runoff characteristics are highly non-uniform and anisotropic, and become increasingly so as the area
under consideration becomes larger. The assumption made for estimating the aquatic Action Area
(based on predicted in-stream dilution) was that the entire landscape exhibited runoff properties
identical to those commonly found in agricultural lands in this region. However, considering the
vastly different runoff characteristics of: a) undeveloped (especially forested) areas, which exhibit
the least amount of surface runoff but the greatest amount of groundwater recharge; b)
suburban/residential areas, which are dominated by the relationship between impermeable surfaces
(roads, lots) and grassed/other areas (lawns) plus local drainage management; c) urban areas, that are
dominated by managed storm drainage and impermeable surfaces; and d) agricultural areas
dominated by Hortonian and focused runoff (especially with row crops), a refined assessment should
incorporate these differences for modeled stream flow generation. As the zone around the
immediate (application) target area expands, there will be greater variability in the landscape; in the
context of a risk assessment, the runoff potential that is assumed for the expanding area will be a
crucial variable (since dilution at the outflow point is determined by the size of the expanding area).
Thus, it important to know at least some approximate estimate of types of land use within that
region. Runoff from forested areas ranges from 45 - 2,700% less than from agricultural areas; in
most studies, runoff was 2.5 to 7 times higher in agricultural areas (e.g., Okisaka et al., 1997;
Karvonen et al., 1999; McDonald et al., 2002; Phuong and van Dam 2002). Differences in runoff
potential between urban/suburban areas and agricultural areas are generally less than between
agricultural and forested areas. In terms of likely runoff potential (other variables - such as
topography and rainfall - being equal), the relationship is generally as follows (going from lowest to
highest runoff potential):
Three-tiered forest < agroforestry < suburban < row-crop agriculture < urban.
There are, however, other uncertainties that should serve to counteract the effects of the
aforementioned issue. For example, the dilution model considers that 100% of the agricultural area
has the chemical applied, which is almost certainly a gross over-estimation. Thus, there will be
assumed chemical contributions from agricultural areas that will actually be contributing only runoff
water (dilutant); so some contributions to total contaminant load will really serve to lessen rather
than increase aquatic concentrations. In light of these (and other) confounding factors, Agency
believes that this model gives us the best available estimates under current circumstances.
6.1.5.9 Aquatic Exposure Estimates
In general, the linked PRZM/EXAMS model produces estimated aquatic concentrations that are
expected to be exceeded once within a ten-year period. The Pesticide Root Zone Model is a process
or "simulation" model that 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. It has two major components: hydrology and chemical transport. Water
movement is simulated by the use of generalized soil parameters, including field capacity, wilting
point, and saturation water content. The chemical transport component can simulate pesticide
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application on the soil or on the plant foliage. Dissolved, adsorbed, and vapor-phase concentrations
in the soil are estimated by simultaneously considering the processes of pesticide uptake by plants,
surface runoff, erosion, decay, volatilization, foliar wash-off, advection, dispersion, and retardation.
Uncertainties associated with each of these individual components add to the overall uncertainty of
the modeled concentrations. Additionally, model inputs from the environmental fate degradation
studies are chosen to represent the upper confidence bound on the mean values that are not expected
to be exceeded in the environment approximately 90 percent of the time. Mobility input values are
chosen to be representative of conditions in the environment. The natural variation in soils adds to
the uncertainty of modeled values. Factors such as application date, crop emergence date, and
canopy cover can also affect estimated concentrations, adding to the uncertainty of modeled values.
Factors within the ambient environment such as soil temperatures, sunlight intensity, antecedent soil
moisture, and surface water temperatures can cause actual aquatic concentrations to differ for the
modeled values.
Unlike spray drift, tools are currently not available to evaluate the effectiveness of a vegetative
setback on runoff and loadings. The effectiveness of vegetative setbacks is highly dependent on the
condition of the vegetative strip. For example, a well-established, healthy vegetative setback can be
a very effective means of reducing runoff and erosion from agricultural fields. Alternatively, a
setback of poor vegetative quality or a setback that is channelized can be ineffective at reducing
loadings. Until such time as a quantitative method to estimate the effect of vegetative setbacks on
various conditions on pesticide loadings becomes available, the aquatic exposure predictions are
likely to overestimate exposure where healthy vegetative setbacks exist and underestimate exposure
where poorly developed, channelized, or bare setbacks exist.
6.1.6 Terrestrial Exposure
6.1.6.1 Incidental Releases Associated With Use
This risk assessment was based on the assumption that the entire treatment area is subject to
pesticide application at the rates specified on the label. Uneven application of the pesticide through
changes in calibration of application equipment, spillage, and localized releases at specific areas of
the treated field that are associated with specifics of the type of application equipment were not
accounted for in this assessment.
6.1.6.2 Residue Levels Selection
The Agency relies on the work of Fletcher et al. (1994) for setting the assumed pesticide residues in
wildlife dietary items. These residue assumptions are believed to reflect a realistic upper-bound
residue estimate, although the degree to which this assumption reflects a specific percentile estimate
is difficult to quantify. It is important to note that the field measurement efforts used to develop the
Fletcher estimates of exposure involve highly varied sampling techniques. It is entirely possible that
much of these data reflects residues averaged over entire above ground plants in the case of grass
and forage sampling.
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6.1.6.3 Dietary Intake
It was assumed that ingestion of food items in the field occurs at rates commensurate with those in
the laboratory. Although the screening assessment process adjusts dry-weight estimates of food
intake to reflect the increased mass in fresh-weight wildlife food intake estimates, it does not allow
for gross energy differences. Direct comparison of a laboratory dietary concentration- based effects
threshold to a fresh-weight pesticide residue estimate would result in an underestimation of field
exposure by food consumption by a factor of 1.25 - 2.5 for most food items.
Differences in assimilative efficiency between laboratory and wild diets suggest that current
screening assessment methods do not account for a potentially important aspect of food
requirements. Depending upon species and dietary matrix, bird assimilation of wild diet energy
ranges from 23 - 80%, and mammal's assimilation ranges from 41 - 85% (U.S. Environmental
Protection Agency, 1993). If it is assumed that laboratory chow is formulated to maximize
assimilative efficiency (e.g., a value of 85%), a potential for underestimation of exposure may exist
by assuming that consumption of food in the wild is comparable with consumption during laboratory
testing. In the screening process, exposure may be underestimated because metabolic rates are not
related to food consumption.
Finally, the screening procedure does not account for situations where the feeding rate may be above
or below requirements to meet free living metabolic requirements. Gorging behavior is a possibility
under some specific wildlife scenarios (e.g., bird migration) where the food intake rate may be
greatly increased. Kirkwood (1983) has suggested that an upper-bound limit to this behavior might
be the typical intake rate multiplied by a factor of 5. In contrast, there may be potential for
avoidance (animals respond to the presence of noxious chemicals in food by reducing consumption
of treated dietary elements). This response is seen in nature where herbivores avoid plant secondary
compounds. However, how these behaviors relate to amphibians is not clear.
T-HERPS uses avian toxicity data as a surrogate for toxicity to amphibians and reptiles. Actual
toxicity data on amphibian and reptiles is frequently unavailable. Although differences in sensitivity
may be expected, the lack of available toxicity data on reptiles and amphibians precludes a robust
comparison to birds. This represents a source of uncertainty in the estimated risks to amphibians and
reptiles. For this assessment, no terrestrial-phase amphibian toxicity data were available so birds
were used as a surrogate for the terrestrial-phase CRLF.
Risk quotients calculated using the dose-based toxicity values are generally higher than RQs
calculated using the dietary-based toxicity values. The dose-based approach considers the uptake
and absorption kinetics of a gavage toxicity study to approximate exposure associated with uptake
from a dietary matrix. Toxic response is a function of duration and intensity of exposure. For many
compounds a gavage dose represents a very short-term high intensity exposure. Although the dose-
based estimates may not reflect reality in that animals do not receive a gavage while feeding, it is
possible that a short-duration, high-intensity exposure could occur associated with feeding on an
agricultural field since many birds may gorge themselves when food items are available. Whether
amphibians exhibit this type of gorging behavior is unclear. On the other hand, the dietary-based
approach assumes that animals in the field are consuming food at a rate similar to that of confined
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laboratory animals despite the fact that energy content in food items differs between the field and the
laboratory as does the energy requirements of wild and captive animals. Also, the design of dietary-
based studies precludes the estimation of food consumption on a per-bird basis since birds are group
housed and tend to spill feed further confounding any estimates of food consumption.
6.1.6.4 Location of Wildlife Species
For this baseline terrestrial risk assessment, a generic bird or mammal was assumed to occupy either
the treated field or adjacent areas receiving a treatment rate on the field. Actual habitat requirements
of any particular terrestrial species were not considered, and it was assumed that species occupy,
exclusively and permanently, the modeled treatment area. Spray drift model predictions suggest that
this assumption leads to an overestimation of exposure to species that do not occupy the treated field
exclusively and permanently.
6.2 Effects Assessment Uncertainties
6.2.1 Estimated Effects Endpoints
6.2.1.1 Use of Acute-to- Chronic Ratio Approach
There are no chronic toxicity data for freshwater fish for ETU (the major degradate of mancozeb and
maneb). An estimated chronic freshwater fish NOAEC of 37.32 ppm was determined using the
acute-to-chronic ratio (ACR) approach. Acute and chronic invertebrate toxicity data conducted with
ETU was used to develop an ACR for ETU (13.45) and then this ACR was applied to the most
sensitive acute freshwater fish toxicity data for ETU to estimate the chronic toxicity value for ETU.
Because the acute fish ETU value was a greater than value (i.e. LC50> 502ppm), the resultant chronic
value will be an overestimate of risk.
6.2.1.2 Use of Surrogate Data for Terrestrial-Phase Amphibians
There is uncertainty associated with lack of toxicity data for terrestrial-phase amphibians. In this
assessment bird toxicity data will be used as a surrogate for terrestrial-phase amphibians based on
the assumption that birds are more sensitive, or at least as sensitive, as terrestrial- amphibians to
mancozeb, maneb, and ETU.
6.2.1.3 Use of Surrogate Data for Aquatic-Phase Amphibians
There is uncertainty associated with lack of toxicity data for aquatic-phase amphibians. In this
assessment freshwater fish toxicity data will be used as a surrogate for aquatic-phase amphibians
based on the assumption that freshwater fish are more sensitive, or at least as sensitive, as aquatic-
phase amphibians to mancozeb, maneb, and ETU.
6.2.2 Aquatic Plant Effects
One study has been submitted for a maneb technical formulation and a mancozeb technical
formulation using the freshwater green algae (P. subcapitatum). Typically, studies are available for
duckweed (Lemna gibba), blue-green algae (Anabaena flos-aquae), freshwater green alga (P.
subcapitatum), and a freshwater diatom species to assess a cross-section of the non-target freshwater
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aquatic plant population. This risk assessment used the submitted P. subcapitatum studies with
mancozeb and maneb for the aquatic freshwater plant endpoint and characterized the potential
endangered species risk with available mixture data on freshwater aquatic plant species. There were
no aquatic plant incident data reported. The approach used in this risk assessment is either an
overestimate or underestimate of risk.
6.2.3 Terrestrial Plant Effects
Terrestrial plant data are not available for mancozeb as a sole active ingredient in the Typical Enduse
Product (TEP). There is also no terrestrial plant data for maneb. Terrestrial plant data for mancozeb
is based on a TEP containing 60% mancozeb co-formulated with 9% dimethomorph. In these
studies the EC25 is higher than the highest concentration tested. In this risk assessment the co-
formulated data was used qualitatively. Terrestrial plant incidents and estimated EECs were used in
characterization. The resulting conclusions of the assessment could be either an over or
underestimation of risk.
6.2.4 Sub-lethal Effects
For an acute risk assessment, the screening risk assessment relies on the acute mortality endpoint as
well as a suite of sub-lethal responses to the pesticide, as determined by the testing of species
response to chronic exposure conditions and subsequent chronic risk assessment. Consideration of
additional sub-lethal data in the assessment is exercised on a case-by-case basis and only after
careful consideration of the nature of the sub-lethal effect measured and the extent and quality of
available data to support establishing a plausible relationship between the measure of effect (sub-
lethal endpoint) and the assessment endpoints.
6.3.5 Age Class and Sensitivity of Effects Thresholds
It is generally recognized that test organism age may have a significant impact on the observed
sensitivity to a toxicant. The acute toxicity data for fish are collected on juvenile fish between 0.1
and 5 grams. Aquatic invertebrate acute testing is performed on recommended immature age classes
(e.g., first instar for daphnids, second instar for amphipods, stoneflies, mayflies, and third instar for
midges).
Testing of juveniles may overestimate toxicity at older age classes for pesticide active ingredients
that act directly without metabolic transformation because younger age classes may not have the
enzymatic systems associated with detoxifying xenobiotics. In so far as the available toxicity data
may provide ranges of sensitivity information with respect to age class, this assessment uses the
most sensitive life-stage information as measures of effect for surrogate aquatic animals, and is
therefore, considered as protective of the California Red Legged Frog.
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7 References
Altig, R. and R.W. McDiarmid. 1999. Body Plan: Development and Morphology. In R.W.
McDiarmid and R. Altig (Eds.), Tadpoles: The Biology of Anuran Larvae.University of Chicago
Press, Chicago, pp. 24-51.
Alvarez, J. 2000. Letter to the U.S. Fish and Wildlife Service providing comments on the Draft
California Red-legged Frog Recovery Plan.
Burns, Lawrence, 2004. Exposure Analysis Modeling System (EXAMS): User Manual and System
Documentation. Ecosystem Research Division, National Exposure Research Laboratory. U. S.
Environmental Protection Agency, Athens, GA.
Carsel, R.F., J.C. Imhoff, P.R. Humel, J.M. Cheplick, and A.S. Donigian, Jr. 1997. PRZM-3, A
Model for Predicting Pesticide and Nitrogen Fate in the Crop Root and Unsaturated Zones: User's
Manual for Release 3.0. National Exposure Research Laboratory, Office of Research and
Development, U. S. Environmental Protection Agency, Athens, GA.
Crawshaw, G.J. 2000. Diseases and Pathology of Amphibians and Reptiles in: Ecotoxicology of
Amphibians and Reptiles; ed: Sparling, D.W., G. Linder, and C.A. Bishop. SETAC Publication
Series, Columbia, MO.
Fellers, G. M., et al. 2001. Overwintering tadpoles in the California red-legged frog (Rana aurora
draytonii). Herpetological Review, 32(3): 156-157.
Fellers, G.M, L.L. McConnell, D. Pratt, S. Datta 2004. Pesticides in Mountain Yellow-Legged
Frogs (Rana Mucosa) from the Sierra Nevada Mountains of California, USA. Environmental
Toxicology & Chemistry 23 (9):2170-2177.
Fellers, Gary M. 2005a. Rana draytonii Baird and Girard 1852. California Red-legged Frog. Pages
552-554. In: M. Lannoo (ed.) Amphibian Declines: The Conservation Status of United States
Species, Vol. 2: Species Accounts. University of California Press, Berkeley, California, xxi+1094
pp.
http://www.werc.usgs.gov/pt reves/pdfs/Rana%20dravtonii.PDF.
Fellers, Gary M. 2005b. California red-legged frog, Rana draytonii Baird and Girard. Pages 198-
201. hr. L.L.C. Jones, et al (eds.) Amphibians of the Pacific Northwest, xxi+227.
Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the
EPA food-chain (Kenaga) nomogram, an instrument for estimating pesticide residues on plants.
Environ. Tox. Chem. 13:1383-1391.
Graves, W.C. M.A. Mank, and J.P. Swigert. 1995. Ethylene Thiourea (ETU): A Flow Through
Life-Cycle Toxicity Test with the Cladoceran (Daphnia magna). Unpublished study performed by
Wildlife International Ltd., Easton, MD. Laboratory Project No. 129A-116. EPA MRID Number
46462901.
140
-------
Hayes and Tennant. 1985. Diet and feeding behavior of the California red-legged frog. The
Southwestern Naturalist 30(4): 601-605.
Hayes, M.P. and M.M. Miyamoto 1984. Biochemical, behavioral and body size differences
between Rana aurora aurora and R a. draytonii. Copeia 1984(4): 1018-22.
Hoerger, F., and E.E. Kenaga. 1972. Pesticide residues on plants: Correlation of representative
data as a basis for estimation of their magnitude in the environment. In F. Coulston and F. Korte,
eds., Environmental Quality and Safety: Chemistry, Toxicology, and Technology, George Thieme
Publ, Stuttgart, West Germany, pp. 9-28.
Jennings, M.R. and M.P. Hayes 1985. Pre-1900 overharvest of California red-legged frogs {Rana
aurora draytonii): The inducement for bullfrog (Rana catesbeiana) introduction. Herpetological
Review 31(1): 94-103.
Jennings, Mark R. 1988. Natural history and decline of native ranids in California. Pp. 61-72. In
Proceedings of the conference on California herpetology. H.F. DeLisle, P.R. Brown, B. Kaufman,
and H.M. McGurty (eds). Southwestern Herpetologists Society Special Publication (4): 1-143.
Jennings, M.R. and M.P. Hayes 1994. Amphibian and reptile species of special concern in
California. Report prepared for the California Department of Fish and Game, Inland Fisheries
Division, Rancho Cordova, California. 255 pp.
Jennings, M.R., S. Townsend, and R.R. Duke. 1997. Santa Clara Valley Water District California
red-legged frog distribution and status - 1997. Final Report prepared by H.T. Harvey & Associates,
Alviso, California. 22 pp.
Karvonen, T., Koivusalo, H., Jauhiainen, M., Palko, J. and Weppling, K. 1999. A hydrological
model for predicting runoff from different land use areas, Journal of Hydrology, 217(3-4): 253-265.
Kelly T. J. et al. 1994. Environ Sci. Technol 28: 378-87.
Kollman, W. S. 2002. Summary of Assembly Bill 1807/3219: Pesticide Air Monitoring Results,
conducted by the California Air Resources Board 1986-2000.
Kupferberg, S.J., J.C. Marks and M.E. Power. 1994. Effects of variation in natural
algal and detrital diets on larval anuran (Hyla regilla) life-history traits. Copeia 1994:446-457.
Kupferberg, S. 1997. Facilitation of periphyton production by tadpole grazing:
Functional differences between species. Freshwater Biology 37:427-439.
LeNoir, J.S., L.L. McConnell, G.M. Fellers, T.M. Cahill, J.N. Seiber 1999. Summertime
Transport of Current-use pesticides from California's Central Valley to the Sierra Nevada Mountain
Range,USA. Environmental Toxicology & Chemistry 18(12): 2715-2722.
141
-------
McConnell, L.L., J.S. LeNoir, S. Datta, J.N. Seiber 1998. Wet deposition of current-use
pesticides in the Sierra Nevada mountain range, California, USA. Environmental Toxicology &
Chemistry 17(10): 1908-1916.
McDonald M.A.1; Healey J.R.; Stevens P.A. 2002. The effects of secondary forest clearance and
subsequent land-use on erosion losses and soil properties in the Blue Mountains of Jamaica.
Agriculture, Ecosystems & Environment, Volume 92, Number 1: 1-19.
Nash R. G. and Beall L. M. 1980. J Agric Food Chem 28: 322.
Okisaka S.; Murakami A.; Mizukawa A.; Ito J.; Vakulenko S.A.; Molotkov I.A.; Corbett
C.W.; Wahl M.; Porter D.E.; Edwards D.; Moise C. 1997. Nonpoint source runoff modeling: A
comparison of a forested watershed and an urban watershed on the South Carolina coast. Journal of
Experimental Marine Biology and Ecology, Volume 213, Number 1: 133-149.
Phuong V.T. and van Dam J. Linkages between forests and water: A review of research evidence
in Vietnam. In. Forests, Water and Livelihoods European Tropical Forest Research Network.
ETFRN NEWS (3pp).
Rathburn, G.B. 1998. Rana aurora draytonii egg predation. Herpetological Review, 29(3): 165.
Reis, D.K. Habitat characteristics of California red-legged frogs (Rana aurora draytonii):
Seale, D.B. and N. Beckvar. 1980. The comparative ability of anuran larvae (genera: Hyla, Bufo
and Rana) to ingest suspended blue-green algae. Copeia 1980:495-503.
Sparling, D.W., G.M. Fellers, L.L. McConnell. 2001. Pesticides and amphibian population
declines in California, USA. Environmental Toxicology & Chemistry 20(7): 1591-1595.
Urban, D.J., and N.J. Cook. 1986. Hazard Evaluation Division Standard Evaluation Procedure
Ecological Risk Assessment. EPA 540/9-85-001. U.S. Environmental Protection Agency, Office of
Pesticide Programs, Washington, DC.
U.S. Environmental Protection Agency (U.S. EPA) 1998. Guidance for Ecological Risk
Assessment. Risk Assessment Forum. EPA/630/R-95/002F, April 1998.
U.S. EPA. 2002. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and
Transport of Pesticides, Version II. Office of Pesticide Programs. Washington, D.C. February 28,
2002.
http://www.epa.gov/oppefedl/models/water/input_guidance2_28_02.htm
U.S. EPA 2005a. Environmental Fate and Ecological Risk Assessment for Mancozeb, Section 4 Re-
registration for Control of Fungal Diseases on Numerous Crops, a Forestry Use on Douglas Firs,
Ornamental Plantings, and Turf.
U.S. EPA 2005b. Environmental Fate and Ecological Risk Assessment for Maneb, Section 4 Re-
registration for Control of Fungal Diseases on Numerous Crops, Ornamental Plantings, and Turf
142
-------
U.S. EPA 2005c. Environmental Fate and Ecological Risk Assessment for Ethylenethiourea (ETU) a
Common Degradate of the Ethylene bis dithiocarbamate Fungicides (EBDCs): Metiram, Mancozeb,
and Maneb. A Part of EFED Section 4 Re-registration for EBDCs for Use in Crops, Some Forestry
Trees, Ornamental Plantings, Seed Treatment, and Turf; to Control a Wide Range of Fungi.
U.S. EPA 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide
Programs. Office of Prevention, Pesticides, and Toxic Substances. Office of Pesticide Programs.
Washington, D.C. January 23, 2004.
U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS) 1998.
Endangered Species Consultation Handbook: Procedures for Conducting Consultation and
Conference Activities Under Section 7 of the Endangered Species Act. Final Draft. March 1998.
U.S. Fish and Wildlife Service (USFWS) 1996. Endangered and threatened wildlife and plants:
determination of threatened status for the California red-legged frog. Federal Register
61(101):25813-25833.
USFWS 2002. Recovery Plan for the California Red-legged Frog (Rana aurora draytonii). Region 1,
USFWS, Portland, Oregon
http://ecos.fws.qov/doc/recoverv plans/2002/020528.pdf
USFWS 2006 Endangered and threatened wildlife and plants: determination of critical habitat for
the California red-legged frog. 71 FR 19244-19346.
USFWS Website accessed: 30 December 2006.
http://www.fws.qov/endanqered/features/rl froq/rlfroq.html#where
USFWS/NMFS 2004. 50 CFR Part 402. Joint Counterpart Endangered Species Act Section 7
Consultation Regulations; Final Rule. FR 47732-47762.
USFWS/NMFS 2004. Memorandum to Office of Prevention, Pesticides, and Toxic Substances,
U.S. EPA conveying an evaluation by the U.S. Fish and Wildlife Service and National Marine
Fisheries Service of an approach to assessing the ecological risks of pesticide products.
Wassersug, R. 1984. Why tadpoles love fast food. Natural History, 4/84.
143
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