In the absence of these data, the aerobic soil metabolism half-life is tripled to 

conservatively estimate the model input for aerobic soil metabolism.

2) Aerobic aquatic metabolism (OCSPP guideline # 835.4300). Acceptable data are 

available for only one aerobic aquatic metabolism study. The guideline stipulates that 

studies using at least two sediment-water systems that are similar to the potential use sites 

in the United States be submitted. In the absence of these data, the aerobic aquatic 

metabolism half-life is tripled to conservatively estimate the model input for aerobic 

aquatic metabolism.

3) Anaerobic aquatic metabolism (OCSPP guideline # 835.4400). Acceptable data are 

available for only one anaerobic aquatic metabolism study. The guideline stipulates that 

studies using at least two sediment-water systems that are similar to the potential use sites 

in the United States be submitted. In the absence of these data, the anaerobic aquatic 

metabolism half-life is tripled to conservatively estimate the model input for anaerobic 

aquatic metabolism.

4) Terrestrial field dissipation (OCSPP guideline # 835.6100). Given the large number of 

registered uses for cypermethrin and zeta-cypermethrin, two terrestrial field dissipation 

studies are insufficient to describe the environmental fate across the entire U.S. 

The available effects data are considered incomplete for the purposes of risk assessment. The 

following data gaps exist: 

1) Avian acute oral toxicity (OCSPP guideline # 850.2100). Avian acute oral toxicity data 

are not available for passerines, which are required under the new 40 CFR Part 158.

 

2) Avian reproduction (OCSPP guideline # 850.2300). Though reproduction data is 

available for cypermethrin, the maximum treatment level tested (50 ppm) in the 

acceptable studies, which did not show adverse effects at the highest treatment level, is 

below expected exposure from use on cotton (66 ppm on short grass). An additional 

study is needed to characterize reproductive effects under real world exposure scenarios. 

3) Freshwater fish acute toxicity test with TEP (Non-Guideline1,2

 1

The DCI will indicate that TEP studies on freshwater invertebrates and freshwater fish are 

required on coformulated products containing the highest ratio of the synergist piperonyl 

butoxide (PBO) to permethrin and the highest ratio of the synergist MGK-264 to permethrin.

). No acceptable acute 

studies for cypermethrin TEP with synergists (PBO or MGK) have been submitted for 

fish. Since cypermethrin can be directly applied to water via application to cattle 

livestock, EPA needs data on the formulated products containing synergists. Without 

toxicity data on the range of TEPs produced, the Agency would have to presume acute 

toxicity to listed and non-listed fish and aquatic-phase amphibians, but would not be able 

to quantify the risk. The TEP should correspond to those formulated products that are 

2 The DCI will require that a study protocol be submitted for review and approval by the Agency 

prior to this study being initiated.
labeled for outdoor uses with the greatest potential for aquatic exposures and contain the 

highest synergist:a.i. ratio.

4) Freshwater invertebrate acute toxicity test with TEP (Non-Guideline3,4). Acute water 

column tests with Hyallela azteca have been requested in pyrethroid problem 

formulations based on the increased sensitivity of this species to pyrethroid insecticides. 

The 850.1020 test guideline for Gammarid amphipods is recommended with appropriate 

modifications to address specific testing needs of H. azteca. The registrant should submit 

a protocol prior to test initiation or submit any open literature studies that may fulfill this 

data gap. The TEP should correspond to those formulated products that are labeled for 

outdoor uses with the greatest potential for aquatic exposures and contain the highest 

synergist:a.i. ratio.

5) Whole sediment chronic invertebrates (in prep OCSPP guideline #s 850.1760, 850.1770, 

and 850.1780). No chronic or sediment toxicity tests for freshwater or marine 

invertebrates have been submitted for cypermethrin to satisfy the Agency’s updated data 

requirements for outdoor uses in 40 CFR Part 158 (October 26, 2007). Chronic whole 

sediment tests on Hyalella azteca, Chironomus tentans, and Leptocheirus plumulosus are 

requested. 

6) Vegetative vigor and seedling emergence (OSCPP guideline #s 850.4150 and 850.4250)5

. 

No acceptable toxicity data are currently available to assess the risk of cypermethrin to 

non-target terrestrial plants. Since cypermethrin has many outdoor uses, vegetative vigor 

and seedling emergence studies are needed. In addition, four minor terrestrial plant 

incidents have been reported to the Agency involving cypermethrin. Phytotoxicity data 

are needed to assess the impact of cypermethrin on non-target terrestrial plants.

7) Aquatic plant growth (OSCPP guideline #s 850.4400 and 850.5400)5

. No acceptable 

toxicity data are currently available to assess the risk of cypermethrin to non-target 

aquatic nonvascular and vascular plants. Since cypermethrin has many outdoor uses, 

aquatic plant growth toxicity studies are requested with either cypermethrin technical or a 

typical end-use product.

Additional detail on the current data gaps for environmental fate and effects is provided in 

Section 7.9. 

 3 The DCI will indicate that TEP studies on freshwater invertebrates and freshwater fish are 

required on coformulated products containing the highest ratio of the synergist piperonyl 

butoxide (PBO) to permethrin and the highest ratio of the synergist MGK-264 to permethrin.

4 The DCI will require that a study protocol be submitted for review and approval by the Agency 

prior to this study being initiated.

5 A Tier II study is required. The DCI will provide that a Tier I plant study may be conducted in 

lieu of a Tier II study with the understanding that any adverse effects observed by the Tier I 

study would necessitate conduct and submission of a Tier II study as well.

2

Table of Contents

1 Purpose........................................................................................................................ 3

2 Problem Formulation .................................................................................................. 4

2.1 Nature of Regulatory Action................................................................................ 4

2.2 Previous Risk Assessments and Scientific Advisory Panels................................ 5

3 Stressor Source and Distribution ................................................................................ 9

3.1 Mechanism of Action......................................................................................... 14

3.2 Overview of Pesticide Usage ............................................................................. 15

3.3 Environmental Fate and Transport..................................................................... 30

4 Receptors................................................................................................................... 33

4.1 Aquatic and Terrestrial Effects .......................................................................... 33

4.1.1 Terrestrial Species....................................................................................... 34

4.1.2 Aquatic Species........................................................................................... 36

4.1.3 Plants........................................................................................................... 42

4.2 Incident Database Review.................................................................................. 43

4.3 Ecosystems Potentially at Risk .......................................................................... 45

5 Assessment Endpoints .............................................................................................. 45

6 Conceptual Model..................................................................................................... 46

6.1 Risk Hypothesis.................................................................................................. 46

6.2 Conceptual Diagram........................................................................................... 47

7 Analysis Plan ............................................................................................................ 52

7.1 Stressors of Concern........................................................................................... 53

7.2 Measures of Exposure ........................................................................................ 53

7.3 Measures of Effect ............................................................................................. 58

7.4 Integration of Exposure and Effects................................................................... 59

7.5 Deterministic and Probabilistic Assessment Methods....................................... 59

7.6 Endangered Species Assessments...................................................................... 59

7.7 Drinking Water Assessment............................................................................... 60

7.8 Endocrine Disruptor Screening Program ........................................................... 60

7.9 Preliminary Identification of Data Gaps ............................................................ 61

7.9.1 7.9.1. Environmental Fate Data Gaps......................................................... 61

7.9.2 7.9.2 Effects................................................................................................ 62

8 References................................................................................................................. 68

9 Fate and Ecotoxicity Bibliography ........................................................................... 70

Appendix A. PRD Data Request Justification Tables .................................................... 98

Appendix B. Reported Cypermethrin Ecological Incident Summaries in the EIIS 

Database.......................................................................................................................... 100
3

1 Purpose

The purpose of this problem formulation is to provide the foundation for the ecological risk 

assessment being conducted for the registered uses of cypermethrin and zeta-cypermethrin. As 

such, it articulates the purpose and objectives of the risk assessment, evaluates the nature of the 

problem, and provides a plan for analyzing the data and characterizing the risk (USEPA, 1998). 

Additionally, this problem formulation is intended to identify data gaps, uncertainties and 

potential assumptions needed to address those uncertainties in characterizing the ecological risk 

associated with the registered uses of racemic cypermethrin (henceforth referred to in this 

document as “cypermethrin”) and zeta-cypermethrin. Since the analytical methods do not 

distinguish cypermethrin from zeta-cypermethrin, the toxicological endpoints are the same, and 

the environmental fate data has been bridged, this problem formulation will refer to both 

chemicals as “cypermethrins”, where appropriate. 

Cypermethrin and zeta-cypermethrin (PC Codes 109702 and 129064) are broad-spectrum 

insecticides used in four major sectors: agricultural settings, 

commercial/industrial/institutional/food & non-food/mosquito abatement, domestic home and 

garden, and pet care. Agricultural products are restricted use, while residential, commercial, and 

industrial products are general use. Cypermethrin is a combination of 8 stereoisomers with 

percentage compositions ranging from 11-14%. Zeta-cypermethrin is an enriched enantiomeric 

mixture of cypermethrin consisting of 4 stereoisomers at a concentration of 24% each and 4 

insecticidally less active stereoisomers at a concentration of 1% each. The mode of action of the 

cypmerethrins is as a fast-acting neurotoxin in insects. It is now well established that severe 

neurological symptoms of poisoning with pyrethroids in mammals and insects are the result of 

modification of sodium (Na+

) channel activity (cellular pores through which sodium ions are 

permitted to enter the axon to cause excitation) (Matsumura 1985). For the structures of 

cypermethrin and zeta-cypermethrin and further identification information, refer to Figures 3-1 

and 3-2 and Table 3.1.

Cypermethrin is formulated as a pressurized liquid, wettable powder, emulsifiable concentrate 

and ready-to-use solution. Zeta-cypermethrin is formulated in many granular forms, as 

emulsifiable, flowable and soluble concentrates, and ready-to-use solution. Based on the 

Reregistration Eligibility Decision [RED] (USEPA 2006b), application methods in agricultural 

and non-agricultural uses are diverse, and include: aircraft, chemigation, groundboom, airblast 

equipment, handheld equipment (e.g., low pressure, handwand sprayers, backpack sprayers, hose 

end sprayers, and handgun sprayers), paintbrushes, termiticide injectors, ready-to-use (RTU) 

aerosol cans, indoor foggers, pump-trigger sprayers, impregnated wipes, and eartags. 

For agriculture uses, the maximum application rate ranges from 0.4 lb. a.i./acre to 3.4 lbs. 

a.i./acre with a minimum retreatment interval ranging from 3-7 days and a pre-harvest interval 

(PHI) ranging from 1 to 14 days. The maximum application rate for non-agricultural uses is 0.44 

lb. a.i./acre, for applications to lawns and turf. Cypermethrin may be applied year-round; thus, in 

some regions of the United States more than one application season per year is possible. 

Because target species could develop resistance to cypermethrin, it appears that multiple seasons 

at the maximum seasonal rate are unlikely. According to BEAD’s Chemical Profile for 
4

cypermethrin and zeta-cypermethrin, “Based on private market pesticide usage data from 1998-

2010, [agricultural] usage for cypermethrin averaged approximately 100,000 pounds active 

ingredient (a.i.) for 1.6 million acres treated. [Agricultural] [u]sage for zeta-cypermethrin 

averaged approximately 90,000 pounds a.i. for 3.7 million acres. (Proprietary Data, 2005-2010). 

Furthermore, the usage data indicates that for non-agricultural use, “data are available for usage 

by pest control operators and lawn care operators, and for uses such as landscape, 

nursery/greenhouse, and foodhandling establishments. Generally, over the reported years (2000 

through 2008), the majority of use was by pest control operators which used more than 500,000 

pounds a.i. in 2000, and more than 400,000 pounds a.i. in 2003. Use by lawn care operators was 

approximately 11,000 pounds a.i. in 2006, while food handling establishments used 

approximately 3,000 pounds a.i. in 2005, and close to 4,000 pounds a.i. in 2008 (Kline & Co., 

Inc. 2000-2008)”. 

2 Problem Formulation

2.1 Nature of Regulatory Action

This report is the Environmental Fate and Effects Division’s (EFED) Problem Formulation for 

the Registration Review of the cypermethrins. Previous risk assessments were completed for the 

use of these chemicals, which serve as the basis for this document.

The Food Quality Protection Act (FQPA) of 1996 mandated the EPA to implement registration 

review (http://www.epa.gov/oppsrrd1/registration_review/). All pesticides distributed or sold in 

the United States generally must be registered by the EPA. The decision to register a pesticide is 

based on the consideration of scientific data and other factors showing that it will not cause 

unreasonable risks to human health, workers, or the environment when used as directed on 

product labeling. In addition, it must not be expected to cause unreasonable adverse effects to 

human health through the dietary and residential routes of exposure under the Federal Food Drug 

and Cosmetic Act (FFDCA). The registration review program is intended to ensure that, as the 

ability to assess risk evolves and as policies and practices change, all registered pesticides 

continue to meet the statutory standard of no unreasonable adverse effects to human health and 

the environment. Changes in science, public policy, and pesticide use practices will occur over 

time. Through the registration review program, the Agency periodically reevaluates pesticides to 

make sure that as change occurs, products in the marketplace can be used safely. 

As part of the implementation of the Registration Review program pursuant to Section 3(g) of 

the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is conducting an 

evaluation to determine whether the cypermethrins continue to meet the FIFRA standard for 

registration. This problem formulation for the environmental fate and ecological risk assessment 

chapter, in support of the registration review, is intended for the initial docket opening the public 

phase of the review process.
5

2.2 Previous Risk Assessments and Scientific Advisory Panels

Cypermethrin was first registered in 1984 by FMC Corporation, who also subsequently 

registered the isomer enriched zeta-cypermethrin in 1992. Current technical registrants for the 

cypermethrins include FMC, Syngenta, United Phosphorus International, and Valent 

BioSciences. Data for the two active ingredients are considered interchangeable. 

The most recent review performed for the cypermethrins was the national-level EFED chapter of 

the Reregistration Eligibility Decision Document (EFED RED, dated July 30th 2005; DP 

Barcode: D289427). The review indicated risk concerns for freshwater and estuarine/ marine 

organisms, including benthic organisms. The RED evaluated six crop scenarios using the 

technical grade active ingredient (TGAI) (CA cotton, MS cotton, NC cotton, TX cotton, GA 

pecans, and CA lettuce (head)). For the agricultural uses, model-generated exposure values 

suggested that application rates can result in acute risk to fish and aquatic invertebrates 

(freshwater and estuarine/ marine) with triggers that included acute risk, restricted use and 

endangered species concern, depending on the crop scenario and endpoint assessed. Although 

concern for estuarine/ marine endangered invertebrates was triggered, EFED noted there were no 

listed species under this category. However, it appears that at the present time there are listed 

estuarine/ marine species. Evaluating chronic risk from this exposure scenario showed that the 

level of concern (LOC) triggers were exceeded for freshwater and estuarine/ marine invertebrates 

and freshwater fish, depending on the crop scenario. Estuarine/ marine fish RQs did not exceed 

the chronic LOC. 

In the RED risk assessment, acute and chronic risk estimates did not exceed the LOCs for listed 

or non-listed mammalian and avian species, except for small birds and mammals feeding 

primarily on short grass (cotton use only). Although the Agency did not conduct a quantitative 

risk assessment for beneficial insects at the time, toxicity studies with honey bees show that the 

cypermethrins are highly toxic on an acute contact basis. This suggests that the cypermethrin are 

toxic to nontarget beneficial insects, as well as listed insect species.

In addition to the RED, there have been multiple Section 3 New Use Risk Assessments 

completed for zeta-cypermethrin (e.g., DP Barcodes: D345424, D378755, D378762, D378759, 

D385091, D385093, D385094, D248635, D258796, D258797, D258798, D258807, D258809, 

and D258810). Risks identified in these assessments were similar to those identified in the RED. 

1999 Scientific Advisory Panel1

A FIFRA Scientific Advisory Panel (SAP) in 1999 examined the sediment toxicity and fate of 

synthetic pyrethroids. In response to a question regarding whether sediment toxicity data on one 

pyrethroid (cypermethrin) could be used to predict sediment toxicity to all pyrethroids, the panel 

generally supported the method of using data from a few pyrethroids to extrapolate information 

on toxicity to other pyrethroids. The panel recommended testing cypermethrin, bifenthrin 

(relatively non-toxic to freshwater aquatic organisms, very insoluble in water, large 

bioconcentration factor) and possibly tefluthrin (highly toxic to freshwater aquatic organisms, 

stable in water, intermediate solubility in water to cypermethrin and bifenthrin). Although this 

 1 http://www.epa.gov/scipoly/sap/meetings/1999/022399_mtg.htm.
6

agreement was made in 1999, the new CFR Part 158 requirements include sediment toxicity tests 

and these studies are considered particularly important for ecological risk assessment of all 

synthetic pyrethroids. 

While the biota-sediment-accumulation-factor is a widely accepted method of assessment of 

bioaccumulation in sediment organisms, the Panel indicated that the bioconcentration data for 

Daphnia and Hyalella should be sufficient to predict bioconcentration of pyrethroids. Finally, 

the Panel indicated that use of a solid phase microextraction (SPME) method to determine the 

dissolved concentration in water could be used to account for sorption of pyrethroids to organic 

carbon and colloids present in the water column in the measurement of bioconcentration factors.

In 2003 and in response to the comments from the SAP on pyrethroids, EFED requested the 

following studies on the pyrethroids cyfluthrin, cypermethrins, esfenvalerate and bifenthrin 

(Rexrode & Meléndez, memorandum dated 12/22/03):

850.1735: Acute Sediment (freshwater)

- Test organism: Hyalella azteca and Chironomus dilutus.

- Duration: 10 days, endpoint is survival.

EFED has received these studies and is currently in the process of reviewing them.They will be 

incorporated into the risk assessment. 

EPA/600/R01/020: Chronic Estuarine/Marine Sediment Testing

- 28 day test on Leptocheirus plumulosus.

- Percentage of neonates that survive as adults.

- Growth rate.

- Reproduction (#eggs/ female, etc.).

- Behavior.

A chronic 65-day freshwater test was also requested only for the cypermethrins. This study has 

not yet been submitted to the Agency.

EPA/600/R-991064: Chronic Freshwater Sediment Testing

- 65 day test on Chironomus dilutus.

- Survival.

- Growth rate.

- Reproduction (# eggs/ female, time to oviposition, proportion of females ovipositing, % 

hatch).

This study has not yet been submitted to the Agency.

2009 Scientific Advisory Panel

OPP presented a “Proposed Common Mechanism Grouping for the Pyrethrins and Synthetic 

Pyrethroids” to a FIFRA SAP in June 2009. OPP proposed two subgroups based on Type I or 

Type II effects related to sodium current tails and neurobehavioral impact, with esfenvalerate and 
7

fenpropathrin showing symptoms of both types. The panel agreed with OPP and indicated that 

substances with mixed characteristics could be included in both groups (see p. 18 of SAP 

minutes, USEPA 2009). The cypermethrins are a Type II pyrethroid insecticide, with a cyanosubstitution in the alpha-position. Other Type II pyrethroids include cyfluthrin, deltamethrin, 

cyphenothrin, fenvalerate, and fluvalinate. This mechanism of action assessment was performed 

by OPP/HED and presented to the SAP to determine if a cumulative human health assessment is 

required for the synthetic pyrethroids. Information on the SAP is available in the docket (with 

non-copyright material available at http://www.regulations.gov) under EPA-HQ-OPP-2008-

0489. HED conducted a conservative screening level cumulative risk assessment in 2011, which 

is also available in the docket under EPA-HQ-OPP-2011-0746.

EFED does not currently conduct cumulative ecological risk assessments for several reasons. 

Specifically, the Division does not currently have the methodology to conduct similar cumulative 

risk assessments for all of the (non-human) biological entities for which EFED has 

responsibility. In addition to addressing the toxicological aspects of the cumulative effects of 

multiple pyrethroids to multiple biological entities, a cumulative ecological risk assessment 

would likely require consideration of exposure at a watershed scale in order to incorporate spatial 

and temporal variability in pyrethroid applications into cumulative exposure assessment. EFED 

does not have the modeling tools developed for conducting this type of assessment. However, 

EFED will consider open literature, currently available models and other lines-of-evidence (e.g., 

monitoring data) as available, to address the potential for cumulative effects of pyrethroids and 

pyrethrins in the risk description of the ecological risk assessment for the cypermethrins.

National Water Quality Assessment (NAWQA)

Cypermethrins are included in the NAWQA sampling and analysis program

(http://infotrek.er.usgs.gov/apex, accessed 12/09/2011). It was measured in 6.7% of water 

samples as “code 61586, Cypermethrin_ water_ filtered_ recoverable_ micrograms per liter.” 

Because cypermethrins are expected to partition to sediments (and therefore suspended solids), it 

is not expected to be found in filtered water samples. Cypermethrins were measured, at a 

detection limit below 1 ppb, in a combination of surface water and ground water samples in all 

50 states except Alaska, Arkansas, the District of Columbia, and North Dakota, Table 2.1 below 

gives the total number of samples analyzed in each state.

Table 2.1. Number of NAWQA Water Samples analyzed for Cypermethrins

State No. of Water 

Samples

State No. of Water 

Samples

AL 62 MO 41

AK 0 MT 35

AZ 64 NE 98

AR 0 NV 65

CA >500 NH 18

CO 197 NJ 147

CT 87 NM 180

DE 14 NY 119

DC 0 NC 118

FL 215 ND 0

GA 195 OH 79
8

HI 15 OK 11

ID 124 OR 64

IL 166 PA 15

IN 124 RI 5

IA 200 SC 116

KS 42 SD 2

KY 2 TN 105

LA 89 TX 345

ME 31 UT 99

MD 80 VT 3

MA 81 VA 69

MI 117 WA 240

MN 153 WV 5

MS 62 WI 125

WY 125

A total of five (5) samples were found to have cypermethrins above the detection limit, as 

detailed in Table 2.2 below. Four of the five detections were in surface water. All detections 

were well below one part-per-billion. However, these concentrations exceed the 96-hour LC50

for Mysid shrimp (0.00475 ppb), and the 96-hour EC50 (0.0036 ppb) and the 10-day LC50

(0.00257 ppb pore water) for Hyalella azteca (Table 4.2). 

Table 2.2. Detections of Cypermethrins in NAWQA Water Samples

State Location Station Cypermethrin, 

ppb

CA Merced county, San JoaquinTulare BasinCulvert discharge to Mustang C A Monte 

Vista Ave, Sta. ID 373115120382801

0.0175

OR Marion county, Willamette 

basin

Zollner Creek near Mt. Angel, OR, Sta 

ID 14201300

0.0062

TN Cocke county, Tennessee 

River Basin

Nolichucky River near Lowland, Sta. ID 

03467609

0.0125

TX Montgomery county, Place 

name TS-60-53-725

Sta. ID 300825095274801 (ground 

water)

0.0086

UT Salt Lake county, Great Salt 

Lake Basin

Little Cottonwood Creek @ Jordan River 

Nr SLC

0.0094

Aquatic Life Criteria and Aquatic Life Benchmarks

The Clean Water Act requires the Agency to publish water quality criteria that accurately reflect 

the latest scientific knowledge on the kind and extent of all identifiable effects on health and 

welfare which might be expected from the presence of pollutants in any body of water, including 

ground water. While these recommended criteria do not, in themselves, impose any 

requirements, states and authorized tribes can use them to develop water quality standards. The 

US EPA Aquatic Life Ambient Water Quality Criteria document may be found at 

http://www.epa.gov/waterscience/criteria/ (accessed 12/06/11). No criteria for cypermethrin 

have been published.

For the cypermethrins, OPP has published aquatic life benchmarks for freshwater species, based 

on the most sensitive species from the most recent risk assessments (refer to the following site

http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm#benchmarks accessed 
9

12/06/11). The benchmarks are 0.195 ppb (fish acute), 0.14 ppb (fish chronic), 0.21 ppb 

(invertebrate acute), and 0.069 ppb (invertebrate chronic).

The Water Quality Criteria Report for Cypermethrin, prepared by University of California at 

Davis for The Central Regional Water Quality Control Board provides aquatic life criteria for 

freshwater species in the Sacramento River and San Joaquin River basins (report can be found at 

http://www.swrcb.ca.gov/rwqcb5/water_issues/tmdl/central_valley_projects/central_valley_pesti

cides/criteria_method/index.shtml accessed 12/19/2011). The report determined that aquatic life 

should not be impacted if the four-day average concentration of cypermethrins does not exceed 

0.002 ppb and if the one-hour average concentration does not exceed 0.001 ppb more than once 

every three years. 

Impaired Water Bodies

The cypermethrins are not identified as a cause of impairment for any water bodies listed as 

impaired under section 303(d) of the Clean Water Act2. In addition, no Total Maximum Daily 

Loads (TMDL) have been developed for the cypermethrins3. More information on impaired 

water bodies and TMDLs can be found at the Agency’s website4

. The Agency invites submission 

of water quality data for this pesticide. To the extent possible, data should conform to the quality 

standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired 

Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and 

Management Process5 in order to ensure they can be used quantitatively or qualitatively in 

pesticide risk assessments.

3 Stressor Source and Distribution

Cypermethrin (CAS number 52315-07-8) is a pyrethroid pesticide prepared from the 

esterification of 3-phenoxybenzaldehyde and 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane 

carboxylic acid. It consists of a mixture of four diastereoisomers, each of which is present as a 

pair of enantiomers, resulting in eight geometrical and optical isomers. Cypermethrin is used to 

control many pests, including those of cotton, fruit, and vegetable crops. It also has several nonagricultural uses, such as for crack, crevice, and spot treatment to control insect pests in stores, 

warehouses, industrial buildings, houses, apartment buildings, greenhouses, laboratories, and on 

ships, railcars, buses, trucks, and aircraft. It may also be used in non-food areas in schools, 

nursing homes, hospitals, restaurants, hotels, in food processing plants, and to control insects on

horses. Cypermethrin is usually formulated as an emulsifiable concentrate or wettable powder

for agriculatural applications, and is usually applied by ground or aerial application as a foliar 

spray. Like all pyrethroids, cypermethrin affects insects by acting as a neural toxin that can 

result in muscle spasms, paralysis and death.

Table 3.1 provides some identification information for cypermethrin and zeta-cypermethrin. The

general structures of both compounds are provided in Figures 3-1 and 3-2.

 2 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

3 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_group_name=PESTICIDES 4 http://www.epa.gov/owow/tmdl/

5 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
10

Figure 3-1. The general structure of cypermethrin

Cypermethrin is a combination of 8 stereoisomers with percentage compositions ranging from 

11-14%, and very low volatility and water solubility. Zeta-cypermethrin is an enriched 

enantiomer of cypermethrin consisting of the 4 stereoisomers with an “S” configuration at the 

cyano-bearing carbon at 24% each, and 4 insecticidally less active stereoisomers at a 

concentration of 1% each. Since the analytical method does not distinguish cypermethrin from 

zeta-cypermethrin, and the toxicological endpoints are the same, the Agency’s environmental 

fate assessment considers both cypermethrins.
11

Figure 3-2. Specific structures of each of the isomers of zeta-cypermethrin

Table 3.1. Identification information for cypermethrin and zeta-cypermethrin

PARAMETER VALUE(s) SOURCES

SMILES notation ClC(Cl)=CC1C(C)(C)C1C(=O)OC(C#N)c2cccc(Oc3ccccc3)c2

Nomenclature of 

Cypermethrin

(IUPAC Names)

(RS)-α-cyano-3-phenoxybenzyl (1RS,3RS,1RS,3SR)-3-

(d,d-dichlorovinyl)-2,2-dimethylcyclopropanecorboxylate

Cypermethrin:

mixture of the stereoisomers (S)-α-cyano-3-phenoxybenzyl 

(1RS,3RS;1RS,3SR)-3-(2,2-dichlorovinyl)-2,2-

dimethylcyclopropanecarboxylate where the ratio of the 

(S);(1RS,3RS) isomeric pair to the (S);(1RS,3SR) isomeric 

pair lies in the ratio range 45-55 to 55-45 respectively

Zeta-cypermethrin: 

USEPA 2006b

Nomenclature of 

Cypermethrin

(CAS Names)

cyano(3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-

2,2-dimethylcyclopropanecarboxylate

Cypermethrin:

(S)-cyano(3-phenoxyphenyl)methyl 3-(2,2-

Zeta-cypermethrin:

USEPA 2006b
12

Table 3.1. Identification information for cypermethrin and zeta-cypermethrin

PARAMETER VALUE(s) SOURCES

dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate

PC Code 109702

Cypermethrin:

129064

Zeta-cypermethrin: USEPA 2006b

CAS Reg. Nos. 52315-07-8 USEPA 2006b

Molecular Formula C22H19Cl2NO3 USEPA 2006b

Molecular Weight 416.3 USEPA 2006b

The structures of cypermethrin and zeta-cypermethrin from the chemical’s data sheet accessed 12/06/2011 and available 

at http://www.alanwood.net/pesticides.html .

Cypermethrins’ water solubility of 4.0x10-3 mg/L and its hydrophobic nature leads to strong soil 

adsorption and a tendency to partition to sediment in aquatic systems. The reported log 

octanol/water partition coefficient value (6.4) suggests that the cypermethrins have the potential 

to bioaccumulate in aquatic organisms, assuming that chemical metabolism is negligible. The 

cypermethrins have a high molecular weight of 416.3 g/mmol. With a vapor pressure of 2.5x10-9

mm Hg and a limited solubility, the calculated Henry’s Law Constant for the cypermethrins is 

relativiely low (3.4x10-7 atm-m3/mol). Table 3.2 lists various important physicochemical 

characteristics of the chemicals. Table 3.14 lists available environmental fate characteristics of 

the cypermethrins, along with information on the major and minor degradates detected in the 

submitted environmental fate studies.

Table 3.2. Physical and Chemical Properties of the Cypermethrins.

Property Value Reference

Water solubility 4.0x10-3 mg/L Laskowski (2002)

Melting point 78-81 oC Tomlin 1994

Boiling point 200 oC at 9.3 Pa Tomlin 1994

Vapor pressure 2.5x10-9 mm Hg Laskowski (2002)

log Kow 6.4 Laskowski (2002)

Henry’s Law constant 3.4x10-7 atm-m3/mol Laskowski (2002)

Cleavage at the ester moiety of the cypermethrins results in two primary degradation products, 3-

(2,2-dichloroethenyl)-2,2-dimethylcyclopropane carboxylic acid (DCVA) and 3-

phenoxybenzaldehyde, which degrades further to 3-phenoxybenzoic acid (3-PBA). Based on the 

assumption that cleavage of the ester bond in the parent compound results in biologically 

inactive degradates, these compounds are not expected to pose greater toxicity to non-target 

organisms; therefore only the parent compounds were considered for toxicological concern for 

both aquatic and terrestrial ecosystems. In fact, this assumption is supported by the results of 

acute toxicity studies in freshwater fish and invertebrates which indicate that the zetacypermethrin degradate 3-phenoxy benzoic acid is much less toxic than the parent compound. 
13

Figure 3.3 shows the chemical structures of the cypermethrins’ major potential degradation 

products. 

Figure 3.3. Nomenclature and Structures of Potential Degradation Products of 

the Cypermethrins

Common 

Name Chemical Name

Structure

DCVA

3-(2,2-

dichloroethenyl)-

2,2-dimethylcyclopropane carboxylic 

acid 

3-phenoxybenzaldehyde
14

3-PBA 3-phenoxybenzoic 

acid 

cyperamide

3.1 Mechanism of Action

The pyrethroids (including the cypermethrins) share similar modes of action, and are considered 

axonic poisons that affect both the peripheral and central nervous system. It is now well 

established that severe neurological symptoms of poisoning with pyrethroids in mammals and 

insects are the result of modification of sodium (Na+

) channel activity (cellular pores through 

which sodium ions are permitted to enter the axon to cause excitation) (Matsumura 1985). 

Advanced electrophysiological experiments using a voltage clamp and a patch clamp, together 

with ligand-binding and ionic flux experiments, have unveiled unique actions of pyrethroids of 

keeping the Na+ channel in the open state for an extremely long period, sometimes as long as 

several seconds. This modification of Na+ channel properties leads to hyperactivity of the 

nervous system. This action leads to spontaneous depolarizations, augmented neurotransmitter 

secretion rate and neuromuscular block, which ultimately results in paralysis of the insect. 

Pyrethroids have also been shown to suppress gamma-aminobutyric acid GABA and glutamate 

receptor-channel complexes and voltage-activated calcium (Ca 2+) channels, but the toxicological 

significance of these actions is uncertain. 
15

Relative to physiological responses, researchers have designated two types of pyrethroids, Type I 

(e.g., pyrethrins, S-bioallethrin, resmethrin, permethrin) and Type II (e.g., the cypermethrins, 

deltamethrin, fenvalerate). The cypermethrins are classified as Type II synthetic pyrethroids, 

with a cyano group at the α-carbon position of the alcohol moiety, and is considered a third 

generation pyrethroid, that is, more light-stable and persistent in the environment than early 

pyrethroids like allethrin, phenothrin (also commonly known as sumithrin) and resmethrin. The 

cypermethrins have three optically active centers and is composed of 8 isomers, and like all 

pyrethroids, is a contact poison that can quickly penetrate the nervous system and have an 

effective “knockdown” action (induction of temporary paralysis) for most flying insects. 

3.2 Overview of Pesticide Usage

The use information presented in this problem formulation was obtained from the tables in 

Appendix A-1 and Appendix A-2 dated 10/12/2011 and 05/24/2011, from BEAD’s Chemical 

Profile for Registration Review (USEPA 2011), from various evaluated labels, and from the July 

2006 Reregistration Eligibility Decision Document for Cypermethrin. Due to the variable use 

patterns for cypermethrin and zeta-cypermethrin, the chemical uses will be discussed separately. 

There are currently 64 Section 3 registered products as well as 13 Special Local Needs (SLN)

registrations for cypermethrin. There are currently 47 Section 3 registered products as well as 50 

SLN registrations for zeta-cypermethrin.

Cypermethrin has numerous uses. A summary of agricultural use patterns based on maximum 

application rate per crop group for cypermethrin and zeta-cypermethrin is shown Table 3.3 and

3.4, respectively. 

Table 3.3. Summary of Agricultural Use Information for the Cypermethrin

Use Maximum 

Applic. Rate 

Maximum Seasonal 

Rate 

Maximum Number 

of Applications 

Minimum 

Retreatment 

Interval 

(days)

Crop Group 1 (Root and Tuber Vegetables): Carrot

Crop Group 3 (Bulb Vegetables): Garlic, Leek, Onion, Shallot 

Crop Group 4 (Leafy Vegetables (Except Brassica)): Lettuce (Leaf and Head), Spinach, Chinese Spinach

Crop Group 5 ( Leafy Brassica Vegetables): Broccoli, Broccoli Raab, Chinese Broccoli, Brussels Sprouts, Cabbage, 

Cauliflower, Collards, Kale, Kohlrabi, Mustard Greens, Mustard Spinach, Rape Greens

Crop Group 14 (Nut Trees): Pecan

Crop Group 15 (Cereal Grains): Corn

Crop Group 20 (Oilseed Crops): Cotton

Crop Group 99 (No Name Group): Chinese Mustard

Crop Group 3 0.1 lb a.i./A 0.5 lb a.i./A NS 7

Crop Group 4 0.1 lb a.i./A 0.6 lb a.i./A NS 7

Crop Group 5 0.1 lb a.i./A 0.6 lb a.i./A NS 7

Crop Group 14 0.1 lb a.i./A 0.6 lb a.i./A NS 7

Crop Group 20 0.1 lb a.i./A 0.6 lb a.i./A NS 5 

Crop Group 99 0.1 lb a.i./A 0.4 lb a.i./A NS 7

Table 3.4. Summary of Agricultural Use Information for the Zeta-Cypermethrin
16

Use Maximum 

Applic. Rate 

Maximum Seasonal 

Rate 

Maximum Number 

of Applications 

Minimum 

Retreatment 

Interval 

(days)

Crop Group 1 (Root and Tuber Vegetables): Arracacha, Arrowroot, Artichoke (Chinese and Jerusalem), Beet (Garden and 

Sugar), Carrot, Cassava, Celeriac, Chayote, Chicaory, Chufa, Dasheen, Ginseng, Horseradish, Leren, parsley, Parsnip, Potato, 

Radish, Rutabaga, Salsify (Black and Spanish), Skirret, Sweet Potato, Tanier, Taro, Turnip, Yam (True and Bean)

Crop Group 2 (Leaves of Root and Tuber Vegetables): Garden Beet, Burdock, Cassava, Chicory

Crop Group 3 (Bulb Vegetables): Garlic, Leek, Onion (Bulb and Green), Shallot

Crop Group 4 (Leafy Vegetables (Except Brassica)): Leafy Amaranth, Arugula, Cardoon, Celery, Celtuce, Chervil, 

Chrysanthemum (Edible Leaved and Garland), Corn Salad, Cress (Garden and Upland), Dandelion, Dock, Endive, Florence 

Fennel, Lettuce (Head and Leaf), Orach, Parsley, Purslane (Garden and Winter), Radicchio, Rhubarb, Spinach (including 

Chinese, New Zealand, and Vine), Swiss Chard, Tampala

Crop Group 5 (Leafy Brassica Vegetables): Broccoli, Broccoli Raab, Chinese Broccoli, Brussels Sprouts, Cabbage (including 

Bok Choy, Mustard, and Napa), Cauliflower, Collards, Kale, Kohlrabi, Mustard Greens, Mustard Spinach, Rape Greens

Crop Group 6 (Legume Vegetables): Bean (Adzuki, Broad, Dry, Kidney, lablab, Lima, Moth, Mung, Navy, Pinto Rice, 

Runner, Snap, Succulent, Tepary, Urd Wax, Yardlong), Catjang, Chickpea, Cowpea, Guar, Jackbean, Lentil, Lupi, Pea 

(Blackeyed, Crowder, Dry, Dwarf, English, Garden, Green, Pigeon, Snow, Southern, Succulent, Sugar Snap), Soybean

Crop Group 7 (Foliage of Legume Vegetables): Soybean, Forage

Crop Group 8 (Fruiting Vegetables): Eggplant, Groundcherry, Okra, Pepino, Pepper (Bell, Nonbell, Sweet Nonbell), 

Tomatillo, Tomato

Crop Group 9 (Cucurbit Vegetables): Balsam Pear, Cantaloupe, Chayote, Cucumber, Chinese Cucumber, Cherkin, Edible 

Gourd, Melon, Muskmelon, Pumpkin, Squash (Summer and Winter), Watermelon, Chinese Waxgourd

Crop Group 10 (Citrus Fruits): Calamondin., Citron, Citrus, Grapefruit, Kumquat, Lemon, Lime, Satsuma, Mandarin, Orange 

(Sour and Sweet), Pummelo, Tangelo, Tangerine

Crop Group 11 (Pome Fruits): Apple, Crabapple, Loquat, Pear, Oriental Pear, Quince

Crop Group 12 (Stone Fruits): Apricot, Cherry (Sweet and Tart), Nectarine, Peach, Plum, Japanese Plum, Prune

Crop Group 13 (Berry and Small Fruits): Blackberry, Blueberry, Currant, Elderberry, Gooseberry, Grape, Huckleberry, 

Loganberry, Raspberry

Crop Group 14 (Nut Trees): Almond, Beechnut, Butternut, Cashew, Chestnut, Chinquapin, Hazelnut, Brazil Nut, Hickory Nut, 

Macadamia Nut, Pecan, Walnut

Crop Group 15 (Cereal Grains): Corn (Field, Pop, and Sweet), Millet, Wild Rice, Grain Sorghum, Triticale, Wheat

Crop Group 16 (Cereal Grans, Forage, Fodder, and Straw): Field Corn, Grass hay, Millet, Rice, Sorghum, Wheat

Crop Group 17 (Grass, Forage, Fodder, and Hay): Bahiagrass, Bentgrass, Bermudagrass, Bluegrass, Big Bluestem, 

Buffalograss, Canary Grass (Annual and Reed), Dallisgrass, Foxtail (Creeping and Meadow), Rangeland Grass, Indiangrass, 

Lovegrass, Orchardgrass, Pangolagrass, Pasture, Sudangrass, Timothy

Crop Group 18 (Nongrass Animal Feed): Alfalfa, Clover, Crownvetch, Kudzu, Lespedeza, Lupin, Sweet Lupin, Sainfoin, 

Trefoil, Velvetbean, Vetch, Milk Vetch

Crop Group 19 (Herbs and Spices): Borage, Chervil, Fennel, Marigold, Mustard, Poppy

Crop Group 20 (Oilseed Crops): Canola, Castorbean, Cotton, Crambe, Flax, Jojoba, Lesquerella, Meadowfoam, Rapeseed, 

Safflower, Sesame, Sunflower

Crop Group 99 (No Name Group): Asparagus, Chinese Mustard, Peanut, Sugarcane, Tea

Crop Group 1 0.05 lb a.i./A 0.3 lb a.i./A NS 4

Crop Group 2 0.025 lb a.i./A 0.11 lb a.i./A 2 7

Crop Group 3 0.05 lb a.i./A 0.25 lb a.i./A NS 7

Crop Group 4 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 5 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 6 0.05 lb a.i./A 0.3 lb a.i./A NS 5

Crop Group 7 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 8 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 9 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 10 0.05 lb a.i./A 0.2 lb a.i./A NS 14

Crop Group 11 0.05 lb a.i./A 0.3 lb a.i/A NS 7

Crop Group 12 0.05 lb a.i./A 0.3 lb a.i/A NS 7

Crop Group 13 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 14 0.05 lb a.i./A 0.25 lb a.i./A NS 7

Crop Group 15 0.05 lb a.i./A 0.3 lb a.i./A NS 3 to 5

Crop Group 16 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 17 0.05 lb a.i./A 0.25 lb a.i./A NS 7 for forage and hay
17

17 days for straw and 

seed

Crop Group 18 0.05 lb a.i./A 0.15 lb a.i./A NS 7

Crop Group 19 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 20 0.05 lb a.i./A 0.3 lb a.i./A NS 7

Crop Group 99 0.1 lb a.i./A 0.4 lb a.i./A NS 7

Cypermethrin and zeta-cypermethrin are Restricted Use Pesticides (RUP) for agricultural uses

because of their acute toxicity to aquatic organisms. For agricultural products, application 

methods include aerial, air blast, ground spray, or chemigation. As per requirements from the 

Reregistration Eligibility Decision (USEPA 2006b, revised in 2008), the following labeling 

statements were required for agricultural products to avoid spray drift and contamination of 

aquatic environments. 

BUFFER ZONE REQUIREMENTS for AGRICULTURAL CROPS

• Vegetative Buffer Strip: 

o Construct and maintain a minimum 10-foot-wide vegetative filter strip of grass of 

other permanent vegetation between the field edge and down gradient aquatic 

habitat (such as, but not limited to, lakes; reservoirs; rivers; permanent streams; 

marshes or natural ponds; estuaries; and commercial fish farm ponds).

o Only apply products containing Cypermethrin/Zeta-cypermethrin onto fields 

where a maintained vegetative buffer strip of at least 10 feet exists between the 

field and down gradient aquatic habitat.

• Buffer Zone for Ground Application (groundboom, overhead chemigation, or 

airblast):

o Do not apply within 25 feet of aquatic habitats (such as but not limited to, lakes, 

reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial fish ponds).

• Buffer Zone for ULV Aerial Application:

o Do not apply within 450 feet of aquatic habitats (such as but not limited to, lakes, 

reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial fish ponds).

• Buffer Zone for Non-ULV Aerial Application:

o Do not apply within 150 feet of aquatic habitats (such as but not limited to, lakes, 

reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial fish ponds).

SPRAY DRIFT MANAGEMENT for AGRICULTURAL CROPS

• Wind Direction and Speed:

o Only apply this product if the wind direction favors on-target deposition.

o Do not apply when the wind velocity exceed 15 mph.

• Temperature Inversion

o Do not make aerial or ground applications into temperature inversions.

o Inversions are characterized by stable air and increasing temperatures with height 

above the ground. Mist or fog may indicate the presence of an inversion in humid 
18

areas. The applicator may detect the presence of an inversion by producing smoke 

and observing a smoke layer near the ground surface.

• Droplet Size:

o Use only Medium or coarser spray nozzles (for ground and non-ULV aerial 

application) according to ASAE (S572) definition for standard nozzles. In 

conditions of low humidity and high temperatures, applicators should use a 

coarser droplet size. 

• Additional Requirements for Ground Applications:

o Wind speed must be measured adjacent to the application site on the upwind side, 

immediately prior to application.

o For ground boom applications, apply using a nozzle height of no more than 4 feet 

above the ground or crop canopy.

o For airblast applications, turn off outward pointing nozzles at row ends and when 

spraying the outer two rows. To minimize spray loss over the top in orchard 

applications, spray must be directed into the canopy.

• Additional Requirements for Aerial Applications:

o The spray boom should be mounted on the aircraft as to minimize drift caused by 

wingtip or rotor vortices. The minimum practical boom length should be used and 

must not exceed 75% of the wing span or 80% rotor diameter.

o Flight speed and nozzle orientation must be considered in determining droplet 

size.

o Spray must be released at the lowest height consistent with pest control and flight 

safety. Do not release spray at a height greater than 10 feet above the crop canopy 

unless a greater height is required for aircraft safety.

o When applications are made with a cross-wind, the swath will be displaced 

downwind. The applicator must compensate for this displacement at the 

downwind edge of the application area by adjusting the path of the aircraft 

upwind.

Cypermethrin is toxic to fish, aquatic invertebrates and beneficial insects. The following 

Environmental Hazards statements are required for products labeled for outdoor uses (USEPA 

2006b):

ENVIRONMENTAL HAZARD STATEMENTS

• This pesticide is toxic to fish, aquatic invertebrates, oysters and shrimp. Do not apply

directly to water, or to areas where surface water is present or to intertidal areas below 

the mean water mark. Do not apply when weather conditions favor drift from treated 

areas. Drift and runoff from treated areas may be hazardous to aquatic organisms in 

neighboring areas. Do not contaminate water when disposing of equipment wash waters. 

• This product is highly toxic to bees exposed to direct treatment on blooming crops or 

weeds. Do not apply this product or allow it to drift to blooming crops or weeds while 

bees are actively visiting the treatment area.

Cypermethrin and zeta-cypermethrin also have multiple non-agricultural uses, as described in 
19

Tables 3.5 and 3.6. 

Table 3.5. Summary of Non-Agricultural Uses for the Cypermethrin

Use Single App. Rate

Number 

of Apps.

Seasonal 

App. Rate

(lb a.i./A)

Interval Between 

Apps. (days)

Non-food Crops Grown Outside: Ornamentals, Flowering and Foliage Plants, and Lawn

Surface applications

(including fire ants and turf diagnostic aid)

Residential:

1.8 lbs. a.i./A NS NS 7

NS = Not specified

Table 3.6. Summary of Non-Agricultural Uses for the Zeta-Cypermethrin

Use Single App. Rate

Number 

of Apps.

Seasonal 

App. Rate

(lb a.i./A)

Interval Between 

Apps. (days)

Non-food Crops in Greenhouse: Ornamental, Flowering and Foliage Plants

Surface applications 0.15 lb a.i/A NS NS NS

Non-food Crops Grown Outside: Ornamentals, Flowering and Foliage Plants, and Lawn

Surface applications

(including fire ants and turf diagnostic aid)

Residential:

0.5 lb a.i./A

Non-residential

0.1 lb. a.i./A

NS 0.5 lb. a.i./A NS

NS = Not specified

The agricultural usage of cypermethrin and zeta-cypermethrin, from the Screening Level Usage 

Analysis (SLUA), is provided in Tables 3.7 and 3.8, respectively. The table is arranged by crop 

in alphabetical order. According to the table, the major agricultural use for cypermethrin is 

cotton, with 80,000 lbs a.i. applied annually, on average, and the major agricultural crop for zetacypermethrin is oranges, with 20,000 lbs. a.i. applied. 

Table 3.7. Screening-Level Estimates of Agricultural Uses of Cypermethrin 

(SLUA)6

Percent Crop Treated

Crop Lbs. A.I. Avg. Max.

Broccoli 1,000 5 10

Brussels Sprouts* <500 N/C N/C

Cabbage <500 <2.5 5

Cauliflower <500 5 10

Cotton 80,000 10 15

Garlic <500 10 15

Lettuce 1,000 5 10

Onions 2,000 10 15

Pecans 5,000 10 10

Spinach <500 <1 <2.5

 6 Dated 01/21/2011
20

Sorted alphabetically. All numbers rounded.

<500 Less than 500 pounds of active ingredient

<2.5 Less than 2.5 percent of crop treated

<1 Less than 1 percent of crop treated

N/C Only Lbs. A.I. available

* CA data only (95% or more of U.S. acres in California)

SLUA data sources include: 

USDA-NASS (United States Department of Agriculture's National Agricultural Statistics 

Service) (pesticide usage data from 2001 to 2008)

Private Pesticide Market Research (pesticide usage data from 2001 to 2008)

 California DPR (Department of Pesticide Regulation) (data for 2000 to 2008)

Table 3.8. Screening-Level Estimates of Agricultural Uses of ZetaCypermethrin (SLUA)7

Percent Crop Treated

Crop Lbs. A.I. Avg. Max.

Alfalfa 15,000 <2.5 5

Almonds <500 <1 <2.5

Apples <500 <1 <2.5

Beans, Green 2,000 15 20

Broccoli 2,000 20 30

Brussels Sprouts * <500 N/C N/C

Cabbage <500 15 30

Caneberries <500 25 40

Canola/Rapeseed <500 <1 <2.5

Cantaloupes <500 5 15

Carrots <500 <2.5 10

Cauliflower <500 15 25

Celery 1,000 35 60

Cherries <500 5 5

Chicory * <500 N/C N/C

Corn 10,000 <1 <2.5

Cotton 15,000 5 10

Cucumbers <500 <2.5 5

Dry Beans/Peas 2,000 5 10

Garlic <500 25 55

Grapefruit 2,000 35 50

Lemons <500 <1 <2.5

Lettuce 15,000 55 65

Onions 2,000 25 30

Oranges 20,000 35 45

 7 Dated 01/21/2011
21

Peaches <500 <2.5 5

Peanuts <500 <1 5

Peas, Green <500 10 15

Pecans 1,000 5 10

Peppers 1,000 15 30

Potatoes <500 <1 5

Pumpkins <500 <2.5 5

Rice 6,000 10 10

Sorghum 2,000 <2.5 <2.5

Soybeans 15,000 <2.5 <2.5

Spinach 1,000 30 45

Squash <500 5 10

Sugar Beets 4,000 15 20

Sugarcane <500 <2.5 <2.5

Sunflowers 2,000 <2.5 5

Sweet Corn 5,000 15 20

Tomatoes 1,000 5 10

Walnuts <500 <1 <2.5

Watermelons <500 <2.5 10

Wheat 5,000 <2.5 5

Sorted alphabetically. All numbers rounded.

<500 Less than 500 pounds of active ingredient

<2.5 Less than 2.5 percent of crop treated

<1 Less than 1 percent of crop treated

N/C Only Lbs. A.I. available

* CA data only (95% or more of U.S. acres in California)

SLUA data sources include: 

USDA-NASS (United States Department of Agriculture's National Agricultural Statistics 

Service) (pesticide usage data from 2001 to 2008)

Private Pesticide Market Research (pesticide usage data from 2001 to 2008)

 California DPR (Department of Pesticide Regulation) (data for 2000 to 2008)

BEAD provided agricultural information by state in its Cypermethrin and Zeta-Cypermethrin

Chemical Profile for Registration Review (USEPA 2011). For cypermethrin, the BEAD report 

states: “In 1998-2000, Georgia was the state with the highest use (20%), followed by Texas 

(19%), California (14%) and Louisiana (12%). Other states (18%) include Arkansas, South 

Carolina, Alabama, North Carolina, Tennessee, and Missouri. In 2008-2010, the state with the 

highest use was again Georgia (27%), followed by Louisiana (20%), and Mississippi (16%), and 

the “other” states accounted for (10%) and included South and North Carolina, Florida, 

California, and Missouri.” For zeta-cypermethrin, the BEAD report states: “[From 1998-2000] 

Arkansas was the state with the highest use (21%) followed by Missouri (16%), and Texas 

(11%), with the “other” states (26%) being Louisiana, California, Arizona, Oklahoma, Alabama, 

and Florida. In 2008-2010, Florida (18%) was the state with the highest use, followed by 
22

California (12%), and Missouri, Illinois, and Texas each at 6%. The “other” states accounted for 

33% of use and included Iowa, Minnesota, Arkansas, Montana, Tennessee, Washington, and 

Indiana.” Figures 3-4 and 3-5 show the 2002 estimated annual agricultural use of cypermethrin 

and zeta-cypermethrin according to the USGS-NAWQA data.

Figure 3-4. Cypermethrin Usage by Crop Reporting District (2006-2010)
23

Figure 3-5. Zeta-cypermethrin Usage by Crop Reporting District (2006-2010)

Tables 3.9 and 3.10 provide a summary of several nonagricultural (terrestrial/ outdoor) or noncrop uses for cypermethrin and zeta-cypermethrin, respectively. The uses are classified by broad 

categories as follows: commercial animal housing, outdoor agricultural premises, residential sites 

– outdoors, and outdoor eating establishments. For various uses, the maximum application rate 

is expressed in units other than “lb a.i./A”. Many of the uses may well involve substantive 

exposure to wildlife, especially aquatic organisms, and they will be assessed accordingly (e.g., 

surface applications).

Table 3.9. Non-Crop Outdoor Uses for Cypermethrin

Use Max. App. Rate/ units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval

(days)

Commercial Animal Housing

Animal areas and quarters; Animal shelters; Catteries; Dog runs; Kennels; Pet grooming shops; Pet stores; Research animal 

quarters; Zoos. (Animals are not present during application)

Surface - Crack and crevice or spot 0.017 lb. a.i./gal NS NS NS

Space – General 0.0032 lb a.i/1,000 ft NS 3 NS NS
24

Table 3.9. Non-Crop Outdoor Uses for Cypermethrin

Use Max. App. Rate/ units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval

(days)

Outdoor Agricultural Premises

Empty Uncultivated Agricultural Areas: Corrals; Dairy areas; Farms; Goat holding areas; Hog operations; Rights-of-way; Sheep 

holding areas.

Empty Cattle Feedlots: Beef cattle operations; Feedlots; Holding lots; Livestock lots; Swine lots and yards

Surface - Crack and crevice or spot 0.017 lb. a.i./gal NS NS NS

Residential Sites – Outdoor

Ant hills; Ant nests; Ant trails; Backyards; Doors; Driveways; Entranceways; Mud dauber, wasp, and yellow jacket nests; Outside 

surfaces of buildings; Patio furniture; Picnic areas; Residential areas; Screens; Siding; Spigots; Storage areas; Tree holes; Under 

eaves; Under siding; Wall voids; Windows.

Nonagricultural Outdoor Buildings/Structures: Atriums; Carports; Decks; Fences; Gazebos; Lanais; Porches; Sheds; Tree houses;

Tunnels and cavities in wood; Verandas; Tents.

Fencerows; Hedgerows; Nonagricultural Rights-of-way; Paths; Patios; Paved Areas: Private Roads; Sidewalks; Garbage bins; 

Dumpsters; Meter boxes; Electrical equipment; Electrical fittings; Manure; Compost piles.

Surface - Crack and crevice or spot 0.017 lb. a.i./gal NS NS NS

Table 3.10. Non-Crop Outdoor Uses for Zeta-Cypermethrin

Use Max. App. Rate/ units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval 

(days)

Commercial Animal Housing

Animal areas and quarters; Animal shelters; Catteries; Dog runs; Kennels; Pet grooming shops; Pet stores; Research animal 

quarters; Zoos. (Animals are not present during application)

Surface – General 5.12 fl oz a.i./gal NS NS NS

Surface - Crack and crevice or spot 0.5 fl oz a.i./1000 ft2 NS NS NS

Surface- perimeter 0.5 fl oz a.i./1000 ft NS 2 NS NS

Outdoor Agricultural Premises

Empty Uncultivated Agricultural Areas: Corrals; Dairy areas; Farms; Goat holding areas; Hog operations; Rights-of-way; Sheep 

holding areas.

Empty Cattle Feedlots: Beef cattle operations; Feedlots; Holding lots; Livestock lots; Swine lots and yards

Surface - General 0.4 fl oz a.i./1000 ft2 NS NS 7

Surface - Crack and crevice or spot 0.4 fl oz a.i./1000 ft NS 2 NS 7

Surface- perimeter 0.4 fl oz a.i./1000 ft2 NS NS 7

Residential Sites – Outdoor

Ant hills; Ant nests; Ant trails; Backyards; Doors; Driveways; Entranceways; Mud dauber, wasp, and yellow jacket nests; Outside 

surfaces of buildings; Patio furniture; Picnic areas; Residential areas; Screens; Siding; Spigots; Storage areas; Tree holes; Under 

eaves; Under siding; Wall voids; Windows.

Nonagricultural Outdoor Buildings/Structures: Atriums; Carports; Decks; Fences; Gazebos; Lanais; Porches; Sheds; Tree houses;

Tunnels and cavities in wood; Verandas; Tents.

Fencerows; Hedgerows; Nonagricultural Rights-of-way; Paths; Patios; Paved Areas: Private Roads; Sidewalks; Garbage bins; 

Dumpsters; Meter boxes; Electrical equipment; Electrical fittings; Manure; Compost piles.

Surface – General 0.003 lb a.i./gal NS NS NS

Surface - Crack and crevice or spot 0.003 lb a.i./gal NS NS NS

Surface- Perimeter 0.003 lb a.i./gal NS NS 7

Other uses for zeta-cypermethrin (Table 3.11) are classified as indoor. They include several 

broad categories as follows: application to agricultural premises and equipment – indoor, 

residential – indoor, commercial/ industrial/ institutional establishments – indoor, eating 

establishments – indoor, food handling and processing establishments – indoor, retail and storage 
25

– indoor, transportation – indoor, and pet premise treatment.

Table 3.11. Indoor Uses for Zeta-Cypermethrin

Use

Max. App. Rate/ 

units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval 

(days)

Residential – Indoor

Household/Domestic Dwellings: Apartments; Cabins; Campers; Condominiums; Dwellings; Homes; Mobile homes; Recreational 

vehicles; Residences; Public housing; Sheds; Toolsheds; Townhouses.

Household/Domestic Dwelling Contents: Beds (cracks, crevices, framework); Bedding; Bookcases; Box springs; Boxes; Cabinets; 

Carpet; Cooking equipment; Cut Flowers; Drawers; Dressers; Draperies; Dryers; Equipment; Fabrics; Flowering plants; Foliage 

plants; Formica; Furniture; Furniture bases; Furniture legs; Glass; Light fixtures; Linoleum; Machinery; Mattresses; Picture frames; 

Plastic fabric bags; Refrigerator; Rugs; Shelves; Shrubs; Sofas and Chairs; Sofa and Chair surfaces; Soffits; Stainless steel; Storage 

drawers; Stored items; Stoves; Tables; Tiles; Trees; Upholstered furniture; Upholstery; Vinyl tile; Washers.

Household/Domestic Dwellings Indoor Food Handling Areas (food covered): Cupboards; Kitchens; Sinks; Underneath sinks; Food 

areas.

Household/Domestic Dwellings Indoor Nonfood Handling Areas: Attics; Basements; Bedrooms; Closets; Closed porches; Crawl 

spaces; Dining rooms; Garages; Pantries; Porches; Solariums; Storage areas; Sun porches; Utility rooms; Bathrooms.

Household Domestic Dwellings Indoor Premises: Baseboards; Closed void areas; Cracks and crevices; Dark corners; Doorframes; 

Door jambs; Doors; Door sills; Drains; Equipment voids; False ceilings; Floors; Foundations; Moldings; Moist places; Niches; 

Pipes; Screens; Soffits; Tunnels and cavities in wood; Walls; Windows; Window frames; Window sills; Weep holes; Woodwork; 

Voids in attics, walls, ceilings, and equipment.

Electrical Supplies/Equipment: Meter boxes; Electrical equipment; Electrical fittings.

Human Clothing (Insect and Mold/Mildew Control): Clothing; Clothing (outerwear); Clothing (in storage); Woolens. 

Garbage cans and Garbage/trash compactors.

Surface applications 0.4 fl oz a.i./1000 ft NS 2 NS 7

Crack/crevice or spot surface 0.4 fl oz a.i./1000 ft NS 2 NS 7

Brush on 0.4 fl oz a.i./1000 ft NS 2 NS 7

Void treatment 0.4 fl oz a.i./1000 ft NS 2 NS 7

Foam treatment 0.5 fl oz a.i./1000 ft NS 2 NS 7

Commercial/Industrial/Institutional Establishments – Indoor

Apartments; Auditoriums; Buildings; Churches; Commercial buildings; Correctional facilities; Communications centers; 

Courthouses; Day care centers; Dormitories; Drugstores; Elevators; Equipment voids; Factories; Fake ceilings; Florists; Food 

service storage and preparation areas; Gas stations; Hotels; Industrial buildings; Industrial installations; Institutions; Interiorscapes; 

Jails; Kitchens; Laboratories; Laundry areas; Lavatories; Libraries; Locker rooms; Lathhouses; Missions; Motels; Movie Theatres; 

Museums; Non-food areas of commercial buildings; Non-residential buildings; Offices and office buildings; Other commercial, 

industrial, and governmental sites; Parking garages; Prisons; Public buildings; Resorts; Schools; Shadehouses; Sheds; Stores; 

Textile mills & warehouses; Theaters; Universities; Utilities/utility rooms; Health care facilities; Hospices; Hospitals; Nursing 

homes; Veterinary clinics.

Surface applications 0.4 fl oz a.i./1000 ft NS 2 NS 7

Crack/crevice or spot surface 0.4 fl oz a.i./1000 ft NS 2 NS 7

Brush on 0.4 fl oz a.i./1000 ft NS 2 NS 7

Eating Establishments –Indoor

Eating Establishments (Food Contact) [Equipment/Utensils; Food Handling Areas; Food Serving Areas]: Cafeterias; Restaurants; 

Mess halls

Surface applications 0.4 fl oz a.i./1000 ft NS 2 NS 7

Crack/crevice or spot surface 0.4 fl oz a.i./1000 ft NS 2 NS 7
26

Table 3.11. Indoor Uses for Zeta-Cypermethrin

Use

Max. App. Rate/ 

units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval 

(days)

Food Handling and Processing Establishments – Indoor

Food Handling and Processing Plant Premises and Equipment (Food Contact): Bakeries; Bottling plants; Beverage plants; 

Canneries; Conveying Equipment; Dried fruit processing plants; Feed areas of commercial buildings; Food areas of commercial 

buildings; Food processing plants; Fruit packing sheds; Mushroom processing plants; Peanut processing plants; Processing areas of 

dried food products; Tobacco processing plants; Wineries

Meat Processing Plant Premises and Equipment (Food Contact): Conveying equipment; Edible product areas of official 

establishments operating under the meat; poultry; shell egg grading and egg products inspection operations; Meat packing plants; 

Poultry processing plants; Rabbit processing plants; USDA inspected meat and poultry plants

Dairies/Cheese Processing Plant Premises and Equipment (Food Contact): Dairies

Egg Processing Plants

Tobacco Processing Plants

Feed Mills/Feed Processing Plants: Conveying equipment; Feed processing and handling sites; Flour mills; Grain mills; Mills;

Milling operations; Roll housing and hoppers; Stored grain mills; Rice mills

Feed/Food Treatment - Storage/Processing/Handling Equipment: Conveying equipment; Grain handling equipment

Surface applications 0.4 fl oz a.i./1000 ft NS 2 NS 7

Crack/crevice or spot surface 0.4 fl oz a.i./1000 ft NS 2 NS 7

Brush on 0.4 fl oz a.i./1000 ft NS 2 NS 7

Void treatment 0.07 oz a.i./sq yd NS NS 7

Retail and Storage – Indoor

Commercial Storage/Warehouses Premises: Brandy storage warehouses; Dried fruit warehouses; Elevators; Food storage areas; 

Freight containers; Peanut storage warehouses; Spirit storage; Storage areas; Storage areas of dried food products; Stored seed 

warehouses; Warehouses; Wine storage warehouses; Tobacco warehouses

Food Stores/Markets/Supermarkets Premises and Equipment: Food marketing - storage- distribution; Grocery and convenience 

stores; Stores; Supermarkets; Conveying equipment; Freight containers; Stored product areas

Food/Feed Storage Areas-Full: Stored product areas.

Surface applications 0.4 fl oz a.i./1000 ft NS 2 NS NS

Crack/crevice or spot surface 0.4 fl oz a.i./1000 ft NS 2 NS NS

Transportation – Indoor

Commercial Transportation Facilities: Airplanes; Boats; Box cars; Buses; Cabins and holds of aircraft; Commercial transportation 

centers; Freight containers; Ocean fright containers; Pallets; Passenger rail cars; Railroad cars; Recreational vehicles; Ships & ships’ 

holds; Trains; Trucks; Trailers; Truck trailers; Livestock hauling equipment; Horse trailers.

Commercial Transportation Facilities – Empty: Grain transportation containers (truck beds; planes; box cars; cargo ship holds); 

Pallets.

Commercial Shipping Containers- Empty: Grain transportation containers (truck beds; planes; box cars; cargo ship holds); Pallets.

Trunks of Automobiles, Taxis, Limousines.

Surface applications 0.4 fl oz a.i./1000 ft NS 2 NS 7

Crack/crevice or spot surface 0.4 fl oz a.i./1000 ft NS 2 NS 7

Brush on 0.4 fl oz a.i./1000 ft NS 2 NS 7

Void treatment 0.07 oz a.i./sq yd NS NS 7

Pet Premise Treatment

Pet Living/Sleeping Quarters: Areas of floors & floor coverings where pets may be present; areas where female insects may crawl to 

lay eggs, and similar hiding places; Dog houses and other sleeping quarters; Dog runs; Pet bedding and premises; Pet premises; Pet 

resting areas; Kennels.

Surface applications 5.12 fl oz a.i./750 ft2 NS NS NS

Crack/crevice or spot surface 0.5 fl oz a.i./1000 ft NS 2 NS NS

Perimeter treatment 0.5 fl oz a.i./1000 ft NS 2 NS NS

Cypermethrin and zeta-cypermethrin also have numerous uses on pets and other animals, as 

indicated in Tables 3.12 and 3.13, respectively. Uses include cattle (beef/range/feeder and 
27

dairy), dairy goats (meat, dairy), dogs/ canines, cats, hogs/ pig/ swine treatments, horses, 

livestock, poultry, and sheep animal treatment, etc. Treatments include direct application to 

livestock and horses (rub on, spray) and direct application to livestock (collar, dust, eartag). For 

cattle, the retreatment interval is 3 days while for pets it is not specified. Applied amounts may 

vary depending on the formulation. Figure 3-6 shows the cattle and calves inventory as of 2007. 

Each dot represents 10,000 cattle and calves. Since exposure to water bodies due to treatment of 

cattle and various other animals is possible, these uses will be assessed in the ecological risk 

assessment to estimate potential cypermethrin exposure following application to livestock.

Figure 3-6 Cattle and Calves Inventory as of 20078

Table 3.12. Pet Care, Cattle andOther Animal Treatments of Cypermethrin

Use Max. App. Rate/ units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval 

(days)

 8

Information obtained from the following website accessed 06/12/2011: 

http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/Ag_Atlas_Maps/Livestock_and_Animals/Live

stock,_Poultry_and_Other_Animals/07-M134.asp
28

Table 3.12. Pet Care, Cattle andOther Animal Treatments of Cypermethrin

Use Max. App. Rate/ units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval 

(days)

Birds: Amazon parrots; Budgies; Canaries; Cockatiels; Finches; Love birds; Macaws; Ostrich; Parakeets; Parrots.

Cats (including kittens), Dogs (including puppies), Monkeys, Ferrets, Rabbits. 

Chimpanzees; Chinchillas; Horses; Llamas; Lemurs; Minks; Ponies; Pot bellied pigs.

Rodents: Gerbils; Guinea pigs; Hamsters; Mice; Rats.

Sprays 0.0007 lb. a.i./animal NS NS NS

Package applicator 17.5 % a.i. NS NS 21

Rub on 1 % a.i. NS NS NS

Table 3.13. Pet Care, Cattle and Other Animal Treatments of Zeta-Cypermethrin

Use Max. App. Rate/ units

Max. No. 

Applications/ 

Year

Max. App. 

Rate per 

Year

Min. App. 

Interval 

(days)

Direct Application to Animals

Cattle (Beef/Range/Feeder and Dairy); Hogs/Pig/Swine; Goats (Meat and Dairy); Kids; Sheep; Lamb; Rabbits; Game Animals 

(including Beefalo, Buffalo, Deer, Exotics such as European red deer, Llamas, Moose, Elk); Livestock (including Donkeys, Horses, 

Ponies, Mules); and Poultry

Collar 0.003 lb. a.i./animal NS NS 3

Dust 0.09 lb. a.i./ 1000 animals NS NS 3

Eartag 0.004 lb. a.i./Animal NS NS 3

For indoor uses, EFED has conducted environmental risk assessments for a few pyrethroids for 

Reregistration Eligibility Decisions (e.g., resmethrin and permethrin). Cypermethrin was not one 

of the assessed chemicals. However, in one study (Weston and Lydy, 2010), several synthetic 

pyrethroids were observed in effluents after secondary treatment from POTWs in the 

Sacramento-San Joaquin Delta. In the study, bifenthrin was the most frequently detected 

pyrethroid from municipal wastewater treatment plant effluents (POTWs) tested in the 

Sacramento-San Joaquin Delta (18 samples tested), and it exceeded the Hyalella azteca EC50. In 

addition, detectable amounts of cypermethrin have been found in water bodies sampled by USGS 

during the NAWQA monitoring program. Based on the above information, there is the potential 

for cypermethrin to reach surface waters via exposure from contaminated drains, even after 

treatment in wastewater plants (POTWs). An additional study on the potential for pyrethroids to 

enter water treatment plants and appear in effluent is being developed by the Pyrethroid Working 

Group (PWG). Eight pyrethroids, including cypermethrin, will be monitored in the study. The 

other pyrethroids include cyfluthrin, bifenthrin, deltamethrin, esfenvalerate, cyhalothrin, 

fenpropathrin, and permethrin. Based on available usage information and considering any 

available and acceptable data in the registration review ecological risk assessment, the Division

will evaluate the potential for exposure to aquatic organisms from the indoor uses of 

cypermethrin (for further details see Section 6, Conceptual Model, and Section 7, Analysis 

Plan).

Use with Synergists

Toxicity data on environmental mixtures of the cypermethrins with other pesticides may be 

evaluated, if available, as part of the ecological risk assessment. It is expected that the toxic 

effect of the cypermethrins, in combination with other pesticides used in the environment, is 
29

likely to be a function of many factors including but not necessarily limited to: (1) the exposed 

species, (2) the co-formulants in the mixture, (3) the ratio of cypermethrin/zeta-cypermethrin and 

co-formulants concentrations, (4) differences in the pattern and duration of exposure among 

formulants, and (5) the differential effects of other physical/ chemical characteristics of the 

receiving waters, such as organic matter present in sediment and suspended water. Quantitatively 

predicting the combined effects of all these variables on mixture toxicity to any given taxa with 

confidence is beyond the capabilities of the available data and methodologies. However, a 

discussion of implications of the available pesticide mixture effects data regarding the 

confidence of risk assessment conclusions will be addressed as part of the uncertainty analysis. 

EFED will consider open literature, currently available models and other lines-of-evidence (e.g., 

monitoring data), as available to address the potential for cumulative effects of pyrethrins and 

pyrethroids in the risk description of the ecological assessment for cypermethrin. 

Piperonyl butoxide (PBO) and MGK-264 are commonly used in formulations with pyrethrins 

and pyrethroids (including the cypermethrins). PBO acts as a potentiator (a reagent that 

increases the toxicity of a chemical) in both mammals and insects because the pyrethroid is not 

metabolized and excreted as quickly in its presence (Stewart 1998). MGK-264, another 

potentiator/synergist used with pyrethroids, has similar effects as those observed for piperonyl 

butoxide (US EPA 2006a). 

The need for synergist toxicity enhancement data with insecticides co-formulated and co-applied 

with synergists is discussed in the EFED Reregistration Review Problem Formulation for

Piperonyl Butoxide, dated December 13, 2010 (USEPA 2010, D378420)9

. Currently, data on the 

extent to which the toxicity of pyrethrins and pyrethroids active ingredients are enhanced by 

varying concentrations of PBO are needed to address the ecological risk of products when coapplied with PBO. The Agency has reviewed and provided comments10 on a proposed study 

protocol that will quantify the enhancement of acute toxicity of pyrethroids to the freshwater 

amphipod, Hyalella azteca, by simultaneous exposure to PBO at varying PBO:pyrethroid ratios. 

It is expected that this comprehensive testing strategy, when augmented with similar acute 

toxicity data with freshwater fish and other selected pesticide active ingredients, will facilitate 

bridging of the synergist toxicity enhancement to other co-formulated or co-applied 

pesticide/synergist active ingredients that are not tested at varying synergist:active ingredient 

ratios. With respect to evaluating ecological risks from co-applied cypermethrin and synergists 

(PBO and MGK-264), the Agency is requesting acute toxicity studies of cypermethrin typical 

end-use products (TEPs) that are co-formulated with PBO and MGK-264 at the highest 

synergist:active ingredient ratio. These TEPs should correspond to those formulated products 

that are labeled for outdoor uses with the greatest potential for aquatic exposures and would be 

conducted with a freshwater fish and a freshwater invertebrate. 

 9 The PBO Problem Formulation is available in the PBO registration review docket at 

www.regulations.gov (EPA-HQ-OPP-2010-0498). 10 “EFED Comments on Pyrethrin Joint Venture and PBTF II Submitted White Paper (including Experimental 

Design), Hyalella protocol and Tank Mix List for Synergism Study Requirements for Piperonyl Butoxide (PBO),” 

July 19, 2011, DP Barcode: D389864.
30

3.3 Environmental Fate and Transport

Table 3.14 summarizes the environmental fate/transport properties of the cypermethrins. 

Structures of the observed degradates are provided in Figure 3.3.

Table 3.14. Summary of the environmental fate properties of the cypermethrins.

Property Value / Degradates observed Reference

Hydrolysis half-life: pH 5

 pH 7

 pH 9

stable

stable

1.8 (acid labeled) and 2.5 days (alcohol label)

cis/trans-DCVA (max. 79% at 120 hr) and 3-

phenoxybenzaldehyde (max. 65% at 120 hr)

MRID 42620501

Aqueous photolysis half-life 36.2 days

3-PBA (max. 35% at 35 days)

MRID 42395701

Soil photolysis half-life sandy loam 55 days

cyperamide (steadily increased to a max. of 13.3%)

MRID 42129001

Aerobic soil metabolism 

half-life

60.7 days (sandy loam, acid label)

59.8 days (sandy loam, alcohol label)

cis/trans-DCVA (max. 24% at 62 days, study duration 150 

days)

MRID 42156601

Anaerobic soil metabolism 

half-life

53.3 days (sandy loam, acid label)

63 days (sandy loam, alcohol label)

cis/trans-DCVA (max. 33% 30 days after flooding), 3-PBA 

(max. 26% at 60 days after flooding or end of study)

MRID 42156602

Aerobic aquatic half-life 8.9 days

10.1 days

trans-DCVA (max. 49% at 30 days), cis-DCVA (max. 19% 

at 30 days), 3-PBA (max. 42% at 30 days); study duration, 

90 or 183 days.

MRID 45920801

Anaerobic aquatic half-life 13.8 days (clay loam, benzyl label)

16.5 days (clay loam, cyclopropyl label)

DCVA (max. 34% at 71 days)

MRID 44876105

Adsorption coefficient

Koc (L/Kg)

----------------------------------

Aged Column Leaching 

Study

328,500 (Sand)

134,900 (Sandy loam)

82,600 (Silty loam) 

20,800

-------------------------------------------------------------------------

(Clay loam)

Degradate cis/trans-DCVA found at up to 13.2% in the 

leachate

MRID 42129003

----------------------

MRID 42129002
31

Table 3.14. Summary of the environmental fate properties of the cypermethrins.

Property Value / Degradates observed Reference

Terrestrial Field Dissipation 

Study

13 days (CA soil)

5 days (LA soil)

MRID 42459601

Bioconcentration factor 

(BCF)

161X edible portion

448X whole fish

883X non-edible

moderately slow depuration, with 10-15% of residues 

remaining after 21 days of depuration

MRID 42868203

The environmental fate data for the cypermethrins was developed mostly with studies on 

cypermethrin; however, some studies were conducted on zeta-cypermethrin. Zeta-cypermethrin 

is expected to have a similar fate profile in the environment as cypermethrin. 

Laboratory studies have indicated that the cypermethrins degrades through a combination of 

biotic and abiotic reactions and is moderately persistent in the environment. Under acidic and 

neutral conditions this compound is relatively stable, but is readily hydrolyzed under alkaline 

conditions with a half-life of approximately 2 days at pH 9. The cypermethrins are relatively 

stable to photolysis in laboratory studies using distilled water at pH 7, with a half-life of 

approximately 36 days. The cypermethrins have been shown to biodegrade in aerobic and 

anaerobic soils with half-lives on the order of about 2 months and in aerobic and anaerobic 

aquatic systems with half-lives on the order of one to two weeks. The cypermethrins are 

considered immobile in soils (Kocs > 20,000 L/Kg) and its potential to leach into groundwater is 

low. If released to water, the cypermethrins will rapidly partition to the sediment compartment 

which acts as an environmental sink for this compound. The cypermethrins bioaccumulate 

moderately in fish (448X in whole fish), with moderate depuration. In terrestrial field dissipation 

studies the cypermethrins do not appear to be very persistent in soils or leach substantially (halflives 1-2 weeks). In supplemental aquatic field dissipation studies (zeta-cypermethrin), the 

chemical appears to persist in the sediment, with reported half-lives of 126 and 181 days in LA 

and CA, respectively.

Degradation and Metabolism

Cypermethrin labeled with 14C at the cyclopropyl and benzyl moieties was relatively stable at pH 

5 and 7 buffered solutions, but degraded rapidly with half-lives of approximately 2 days in pH 9 

solutions. The major degradation products of the base catalyzed hydrolysis of cypermethrin 

were cis- and trans- DCVA (maximum 79% at 120 hours or study duration) and 3-

phenoxybenzaldehyde (maximum 65% at 120 hours). Photolysis of cypermethrin in distilled 

water occurs slowly, but the rate of degradation appears to be enhanced in natural waters, which 

contain humic and fulvic acids. A photolysis half-life of 36 days was observed for cypermethrin 

in pH 7 aqueous buffered solution exposed to sunlight in California from March to April. 

Shorter half-lives on the order of less than 1 to 4 days were observed for cypermethrin dissolved 

in river water, seawater and distilled water with 1% humic acid exposed to sunlight (Takahashi et 

al. 1985). The half-life for thin films of cypermethrin in a sandy loam soil matrix was 

approximately 55 days; however, degradation was also observed in control samples and the dark 
32

control corrected half-life is over 100 days. The only transformation product observed was 

cyperamide, at 13.3% at the end of the study (35 days). Cypermethrin degraded with a half-life 

of approximately 60 days in a fine sandy loam soil maintained at 25 oC and held under aerobic 

conditions. Carbon dioxide and a mixture of cis- and trans- DCVA (maximum 24% at 62 days in 

a 150 day study) were the major degradation products.

Under aquatic conditions, cypermethrin degraded more rapidly (8.9-10.1 days in a supplemental 

aerobic aquatic study and 13.8-16.5 days in an anaerobic aquatic study). Degradation products 

(see Figure 3.3 for structures) under aerobic aquatic conditions included trans-DCVA (max. 

49% at 30 days), cis-DCVA (max. 19% at 30 days) and 3-PBA (max. 42% at 30 days, study 

duration 183 days). Under anaerobic conditions, the only degradation product was DCVA at 

34% at 71 days (study duration 90 days for benzyl label and 183 days for cyclopropyl label).

Additional data are needed for risk assessment under guidelines 835.4100 (Aerobic Soil 

Metabolism) and 835.6100 (Terrestrial Field Dissipation). Also, because the greatest exposure 

route of concern is expected to be sediment, additional data are needed for aerobic and anaerobic 

aquatic metabolism (guidelines 835.4300 and 835.4400, respectively) to describe the variability 

of the cypermethrins’ fate across the entire U.S.

Soil Sorption and Mobility

Cypermethrin is considered immobile in soil. Soil organic carbon adsorption coefficients (Koc) 

for cypermethrin ranged from approximately 21,000 to 385,000 L/Kg in four soils (sand, sandy 

loam, silty loam and clay). If released into water, cypermethrin rapidly partitions to the sediment 

column. The tendency to adsorb to soil and sediment along with the relatively low vapor 

pressure (2.5x10-9 mm Hg) and Henry’s law constant (3.4x10-7 atm-m3

/mol), indicates that 

volatilization from water and soil will not be an important transport process. It can be concluded 

that the cypermethrin degradates 3-PBA and trans-DCVA have a high potential for mobility as 

they were weakly sorbed to four soils tested. 3-PBA was slightly more sorbed (Koc values 

ranging from 118 to 215) to the tested soils than was trans-DCVA (Koc values ranging from 18 

to 48). 

Field Dissipation

Terrestrial field dissipation studies conducted in Madera, CA and Cheneyville, LA indicated that 

the field dissipation half-life of formulated cypermethrin is approximately 1 to 2 weeks. 

Cypermethrin in the form of Ammo 2.5 EC was applied three times at 0.2 lb ai/acre/application 

to a bare silt loam soil (78-82% sand, 14-20% silt, 2-4% clay, 0.2-0.6% OM, pH 6.5-7.2) located 

in Madera, California and soil samples were analyzed for cypermethrin and potential degradates 

cis-DCVA, trans-DCVA, and 3-phenoxybenzoic acid. Cypermethrin was detected in 3-6" cores 

collected immediately after each application (18, 8, and 33 μg/kg), and on day 2 (20 μg/kg) and 

day 4 (29 μg/kg) following the third application. Cypermethrin was detected at 10 μg/kg in one 

6-12" core collected 2 days after the final application, but it was not detected in any soil cores 
33

collected below this depth (detection limit of 7 μg/kg). The degradate 3-phenoxybenzoic acid 

was detected in 0-3" cores collected immediately after the second application (8 μg/kg), 

immediately after the third application (17 μg/kg), and the following days after the third 

application: day 2 (25 μg/kg), day 4 (32 μg/kg), day 7 (25 μg/kg), day 14 (24 μg/kg), day 21 (8 

μg/kg), and day 28 (7 μg/kg). It was not detected above a detection limit of 7 μg/kg in any soil 

cores collected below 3 inches. Potential degradates cis- and trans-DCVA were not detected 

above the detection limit of 7 μg/kg in any of the soil cores. An analysis of the cypermethrin 

concentration as a function of time yielded a field dissipation half-life of 13 days. 

In a second study, cypermethrin in the form of Ammo 2.5 EC was applied three times at 0.2 lb 

a.i./acre/application to a bare loamy sand soil (30% sand, 64% silt, 6% clay, 0.7% OM, pH 7.0) 

located in Cheneyville, LA. The soil cores were analyzed for cypermethrin and potential

degradates cis-DCVA, trans-DCVA, and 3-phenoxybenzoic acid. Based upon dissipation in the 

top 0-3" soil cores, the dissipation half-life for cypermethrin was 5 days. Cypermethrin was not 

detected above a detection limit of 7 μg/kg in any cores collected below 3 inches. The degradate 

trans-DCVA was detected in 0-3" cores collected on the following days after the third 

application: day 2 (16 μg/kg) and day 7 (8 μg/kg). The degradate 3-phenoxybenzoic acid was 

detected in 0-3" cores collected immediately after the second application (10 μg/kg), 

immediately after the third application (20 μg/kg), and 2 days after the 3rd application (44 

μg/kg). The degradate cis-DCVA was not detected above a detection limit of 7 μg/kg in any of 

the soil cores. None of the analytes were detected above a detection limit of 7 μg/kg in any of 

the soil cores collected below 3 inches.

Given the large number of registered uses, additional data under this guideline (835.6100, 

Terrestrial Field Dissipation) are needed to describe variability across the U.S.,.

Cypermethrin is not labeled for use in aquatic sites; however, there are two supplemental aquatic 

field dissipation studies conducted with zeta-cypermethrin in California and Louisiana. The 

half-lives were 181 days and 126 days, respectively. These half-lives are not similar to those 

observed in the laboratory studies. Nevertheless, the reported half-lives included the sediments 

only.

EFED is currently reviewing a “washoff” study that measured cypermethrin washoff from 

various building materials. Though this study is currently under review it appears that 

cypermethrin applied to vinyl siding has the highest potential for washoff.

A POTW study to determine the fate of the cypermethrins in sewage treatment works is being 

requested to to ascertain whether indoor and urban cypermethrin uses contribute to toxicity in 

receiving waters or sediments after discharge of treated sewage.

4 Receptors

4.1 Aquatic and Terrestrial Effects

The receptor is the biological entity that is exposed to the stressor (EPA, 1998). Due to the 
34

outdoor uses of the cypermethrins, the types of receptors that may be exposed include both 

aquatic and terrestrial receptors, such as birds, reptiles, mammals, amphibians, freshwater and 

estuarine/marine fish, non-target terrestrial and aquatic invertebrates and terrestrial and aquatic 

plants. The stressors in this case are the cypermethrins. Spray drift and runoff exposures are 

expected for both ground and aerial applications of the cypermethrins. Consistent with the 

process described in the Overview Document (USEPA, 2004), this risk assessment uses a 

surrogate species approach in its evaluation of the cypermethrins. Toxicological data generated 

from surrogate test species, which are intended to be representative of broad taxonomic groups, 

are used to extrapolate to potential effects on a variety of species (receptors) included under 

these taxonomic groupings. 

Tables 4.1 and 4.2 provide a summary of the taxonomic groups and the surrogate species tested 

to help understand potential acute and chronic ecological effects of the cypermethrins to these 

non-target taxonomic groups. 

4.1.1 Terrestrial Species

For terrestrial species, data were submitted for both cypermethrin and zeta-cypermethrin. Since 

zeta-cypermethrin has a similar toxicological profile to cypermethrin the available data for both 

chemicals were considered. A summary of the most sensitive endpoints from the available 

toxicity studies conducted with terrestrial species is presented in Table 4.1. Summaries of the 

available studies will indicate whether cypermethrin or zeta-cypermethrin was used. 

Table 4.1 Summary of most sensitive endpoints from submitted terrestrial toxicity studies for 

the cypermethrins. 

Species 

(common 

name)

Taxa 

Represented Endpoint Concentration

Test 

Substance 

(% a.i.)

Reference/ 

Classification

Acute 

Toxicity 

Classification

Rattus 

norvegicus

(Laboratory 

Rat)

Mammals

LD50 86 mg a.i./kg-bw TGAI

MRID# 

41776115

Acceptable

Moderately 

toxic

NOAEL 5 mg a.i./kg/day

TGAI

MRID# 

00090040

Acceptable

Not 

LOAEL 25 mg a.i./kg/day Applicable

Bobwhite quail 

(Colinus 

virginianus) Birds, 

terrestrialphase 

amphibians, and 

reptiles

LD >2000 mg a.i./kg 

bw 50 TGAI

MRID# 

44546024

Acceptable

Practically 

non-toxic

Mallard duck

(Anas 

platyrhynchos)

LC >2634 mg a.i./kg 

diet 50 TGAI

MRID# 

00090071

Acceptable

Practically 

non-toxic

Bobwhite quail 

(Colinus NOAEL 50 mg a.i./kg-diet TGAI MRID# 00090073

Not 

Applicable
35

Table 4.1 Summary of most sensitive endpoints from submitted terrestrial toxicity studies for 

the cypermethrins. 

Species 

(common 

name)

Taxa 

Represented Endpoint Concentration

Test 

Substance 

(% a.i.)

Reference/ 

Classification

Acute 

Toxicity 

Classification

virginianus)

Mallard duck

(Anas 

platyrhynchos)

LOAEL > 50 mg a.i./kg-diet TGAI

Acceptable

MRID# 

00090074

Acceptable

Not 

Applicable

Apis mellifera

(Honey bee)

Terrestrial 

invertebrates

Contact 

LD 0.023 μg a.i./bee 50

TGAI Acc. No. 

260647

Acceptable

Very highly 

toxic

Oral

LD 0.172 μg a.i./bee 50

TGAI Very highly 

toxic

Terrestiral 

Plants EC50 No Data No Data No Data No Data

The results of the single acute oral toxicity study available for the cypermethrins indicate that the 

chemicals are practically non-toxic to avian species on an acute oral basis. The acute oral LD

Birds

50

value for bobwhite quail (Colinus virginianus) is >2000 mg a.i./kg-bw and no clinical signs of 

toxicity were observed at any treatment level (MRID 44546024). 

No acute avian oral studies with the cypermethrins have been submitted for passerine species.

The results of the sub-acute dietary toxicity studies available for the cypermethrins indicate that 

it can be classified as practically non-toxic to avian species on an acute dietary basis. The LC50 is 

greater than 2,634 mg a.i./kg-diet for mallard duck (Anas platyrhynchos) (MRID 00090071). In 

this study, the LC50 value was determined based on the repellent nature of the treated feed, 

which resulted in decreased food consumption and body weight. 

The results of avian reproduction studies available for the cypermethrins indicate that they can be 

classified as slightly toxic to avian species on a chronic basis. The study showed no adverse 

effects at 50 mg a.i./kg-diet, which was the highest dose tested. 

Mammalian toxicity data submitted to the Agency's Health Effects Division (HED) are used to 

approximate toxicity to wild mammals. These studies are typically conducted with laboratory 

rats (Rattus norvegicus) or mice (Mus musculus). No studies evaluating toxicity to wild mammal 

species are not available, or have been submitted to the Agency for the cypermethrins. 

Mammals

Acute oral, dermal and inhalation mammalian toxicity studies with cypermethrin were submitted 

to the Agency. In addition, chronic dietary and 3-generation rat reproduction studies have also 

been submitted for cypermethrin. These studies were presented in the HED chapter of the 

Reregistration Eligibility Decision Document (RED) for cypermethrin (US EPA, 2006).
36

The reported laboratory rat acute oral LD50 value is 86 mg/kg-bw for cypermethrin (MRID 

41776115). The acute dermal LD50 >4920 mg/kg /day for cypermethrin, based on a study 

conducted with rats (MRID 00056800). An acute inhalation conducted with rats resulted in an 

LC50 >2.5 mg/L for cypermethrin (MRID 42395702). Based on these reported laboratory rat 

LD50 values, cypermethrin has moderate acute toxicity to small mammals via the oral, dermal 

and inhalation exposure routes.

In the available 3-generation rat reproduction study, the NOAEL is 5 mg/kg/day based on 

decreased F1 pup body weight and body weight gain (MRID 00090040). In the submitted 

chronic mammalian dietary study with cypermethrin, the NOAEL is 6 mg/kg/day based on 

clinical signs of neurotoxicity and mortality in males at the 20.4 mg/kg/day treatment level and 

deceased body weights in females at the 18.1 mg/kg/day treatment level (MRID 44536801). 

The Agency guideline terrestrial invertebrate tests are for honey bees (Apis mellifera). The acute 

contact LD

Terrestrial Invertebrates

50 value is 0.023 μg a.i./bee and the oral LD50 value is 0.172 μg a.i./bee (Accession 

Number 260647). Based on these results, the cypermethrins are classified as ‘highly toxic’ to 

honey bees on an acute exposure basis. 

4.1.2 Aquatic Species

For aquatic species, data were again submitted for both cypermethrin and zeta-cypermethrin. 

Since zeta-cypermethrin has a similar toxicological profile to cypermethrin the available data for 

both chemicals were considered. A summary of the most sensitive endpoints from the available 

toxicity studies conducted with aquatic species is presented in Table 4.2. 

4.2. Summary of most sensitive endpoints from submitted aquatic toxicity studies for the 

cypermethrins. 

Exposure 

Scenario Species Exposure Duration

Toxicity 

Reference 

Value

Effects Reference Toxicity 

Category

Freshwater Fish

Acute Rainbow 

trout

(Oncorhynch

us mykiss)

96 hours LC50 = 0.39 μg 

a.i./L

Mortality MRID 44546027

Acceptable

Very Highly 

Toxic

Chronic Fathead 

minnow

(Pimephales 

promelas)

30 days NOAEC = 0.14 

μg a.i./L

LOAEC = 0.33 

μg ai/L

Growth and 

mortality

MRID 00089039

Acceptable

NA

Freshwater Invertebrates

Acute Amphipod 96 hours EC50 = 0.0036 Mortality MRID 44423501

Acceptable

Very Highly 

Toxic
37

4.2. Summary of most sensitive endpoints from submitted aquatic toxicity studies for the 

cypermethrins. 

Exposure 

Scenario Species Exposure Duration

Toxicity 

Reference 

Value

Effects Reference Toxicity 

Category

(Hyalella 

azteca)

μg a.i./L

Benthic Organisms

Acute Amphipod

(Hyalella 

azteca)

10 days sediment value

LC

(experimental 

data): 

50 = 3.6 μg 

a.i./kg sediment

pore water value

(derived data) a

LC

:

50 = 0.00257 

μg a.i./L pore 

water 

Mortality and 

Growth

MRID 44074406

Acceptable

Very Highly 

Toxic

Estuarine/Marine Fish

Acute Sheepshead 

minnow

(Cyprinidon 

variegates)

96 hours LC50 = 0.95 μg 

a.i./L

Mortality MRID 00090075

Acceptable

Very Highly 

Toxic

Estuarine/Marine Invertebrates

Acute Mysid 

shrimp

(Mysidopsis 

bahia)

96 hours b LC50 = 0.00475 

μg a.i./L

Mortality Acc. No. 070562

Acceptable

Very Highly 

Toxic

Chronic Mysid 

shrimp

(Mysidopsis 

bahia)

28 days c NOAEC = 

0.000781 μg 

a.i./L

LOAEC = 

0.00197 μg/L

Weight of 

Females reduced

MRID 42725301

Acceptable

Very Highly 

Toxic

Aquatic Plants

No Data No Data No Data No Data No Data No Data

a For benthic organisms, the LC50 value of 0.00257 μg a.i./L pore water was calculated as follows. The LC50 value in whole 

sediment [3.6 μg a.i./kg sediment] is divided by the proportion of organic carbon in the sediment [0.0099 kg OC/kg whole 

sediment]. Thus, the LC50 value in units of OC is 364 μg a.i./kg OC [3.6μg a.i./kg sediment ÷ 0.0099 kg OC/kg sediment]. 

The equivalent concentration in pore water is based on the definition of the Koc

K

,

oc (L/kg OC) = Sediment Conc in OC (mg/kg OC) ÷ Conc in pore water (mg/L).

By rearrangement,

Conc in water = Sediment Conc in units of OC ÷ Koc.

For the cypermethrins, the Koc is taken as 141,700 [L/kg OC]. Thus, the calculated concentration in pore water corresponding 

to the LC50 value of 364 μg a.i./kg OC is 0.00257 μg a.i./L [364 μg a.i./kg OC ÷ 141,700 L/kg OC].
38

4.2. Summary of most sensitive endpoints from submitted aquatic toxicity studies for the 

cypermethrins. 

Exposure 

Scenario Species Exposure Duration

Toxicity 

Reference 

Value

Effects Reference Toxicity 

Category

b

 The acute toxicity reference value identified to calculate acute RQs for estuarine/marine invertebrates is for a 96-hour 

exposure duration, rather than the guideline recommended 48-hour exposure duration. Although 48-hour LC50 values have 

been reported in other studies (see Appendix E), these values are higher than the 96-hour LC50 of 0.005 μg a.i./L. Taking the 

most conservative approach, EFED will use the lowest LC50 value reported for estuarine/marine invertebrates. c

 The exposure duration of 28 days was not reported in the DER for this study. Since this study was classified as 

“Acceptable” by EFED, an exposure duration of 28 days is assumed.

Freshwater Fish

The acute toxicity of technical grade cypermethrin to freshwater fish was evaluated in several 

species, with 96-hour LC50 values ranging from 0.39 μg a.i./L in rainbow trout (MRID 

44546027) to 4.5 μg a.i./L in bluegill sunfish (MRID 44546030). Based on these results, 

cypermethrin is categorized as very highly toxic to freshwater fish on an acute basis. Taking the 

most conservative approach, the lowest 96-hour LC50 of 0.39 μg a.i./L in rainbow trout is used to 

evaluate acute toxic exposure to freshwater fish. 

Studies assessing the acute toxicity of three cypermethrin formulations in rainbow trout were 

also submitted. The formulations tested were GFU 061(36% a.i.), and GFU 070 (25.1% a.i.). 

The 96-hour LC50 values reported for GFU 061 and GFU 070 are 4.7 μg formulation/L (MRID 

00065813) and 13.0 μg formulation/L (MRID 00088947), respectively, indicating that these 

cypermethrin formulations are very highly toxic to freshwater fish. Comparison of the 96-hour 

LC50 value for cypermethrin TGAI (0.39 μg a.i./L) and cypermethrin formulations (4.7 to 13.0 

μg formulation/L; equivalent to approximately 1.2 to 5.2 μg a.i./L) indicates that the formulated 

products have a similar order of toxicity to technical grade cypermethrin.

Acute toxicity studies in freshwater fish were also submitted for the cypermethrin degradate 3-

phenoxybenzoic acid in rainbow trout (MRID 00089037) and bluegill sunfish (MRID 

00089038). Results yield 96-hour LC50 values of 13.3 and 36.3 mg degradate/L in rainbow trout 

and bluegill sunfish, respectively. Based on these 96-hour LC50 values, 3-phenoxy benzoic acid 

is categorized as slightly toxic to freshwater fish on an acute basis and is much less toxic than 

cypermethrin TGAI to freshwater fish.

An early life-stage study in fathead minnow was submitted by the registrant to establish the 

chronic toxicity of cypermethrin to freshwater fish (MRID 00089039). Results of this 30-day 

exposure study showed that survival was significantly reduced compared to controls at 0.33 μg 

a.i./L, yielding a 30-day NOAEC value for survival of 0.14 μg a.i./L. No treatment-related 

effects were observed for hatchability or growth. The NOAEC value for survival of 0.14 μg 

a.i./L is > 0.1 of the 60-day EEC11

 11 60-d EEC of 0.131 μg a.i./L (based on North Carolina Fruit and coarse droplets, from the RED) ÷ rainbow trout 

ELS NOAEC (0.14 μg a.i./L, MRID 00089039) = 0.9.

, indicating the need for chronic fish studies per 40 CFR part 
39

158. Chronic studies are also triggered by the direct applications to water for the cattle livestock 

use. No acceptable chronic toxicity studies for cypermethrin formulations or cypermethrin 

degradates to freshwater fish were submitted.This is a data gap.

Estuarine/Marine Fish

The acute toxicity of technical grade cypermethrin to estuarine/marine fish was evaluated in 

sheepshead minnow and Atlantic salmon, with 96-hour LC50 values of 0.95 μg a.i./L (MRID 

00090075) and 4.3 μg a.i./L (MRID 41968212) respectively, indicating that the cypermethrins

TGAI is very highly toxic to estuarine/marine fish on an acute basis. Taking the most 

conservative approach, the lowest 96-hour LC50 value of 0.95 μg a.i./L in sheepshead minnow 

will be used to evaluate acute toxic exposure to estuarine/marine fish. No acute toxicity studies 

of cypermethrin formulations or cypermethrin degradates in estuarine/marine fish were 

submitted.

No valid chronic toxicity studies on technical grade cypermethrin in estuarine/marine fish were 

submitted. The previous assessment conducted in support of the RED calculated acute-tochronic ratios based on available acute toxicity data based on the following mathematical 

relationship:

Freshwater LC50 (0.39 μg a.i./L) / Freshwater NOAEC (0.14μg a.i./L) = 

Estuarine/Marine LC50 (0.95 μg a.i./L)/ X (estimated value for Estuarine/Marine 

NOAEC), where X = 0.34 μg a.i./L. 

This estimated NOAEC of 0.34 μg a.i./L is > 0.1 of the 60-day EEC 12, indicating the need for 

chronic fish studies per 40 CFR Part 158. No chronic toxicity studies for the formulations or 

degradates of the cypermethrins in estuarine/marine fish were submitted. This is identified as a 

data gap. 

Freshwater Invertebrates

Acute toxicity studies of technical grade cypermethrin to freshwater invertebrates yield toxicity 

values ranging from a 96-hour LC50 value of 0.0036 μg a.i./L in Hyalella (MRID 44423501) to a 

24-hour LC50 value of >5.0 μg a.i./L in Notonecta, Chironomus thummi, and Lymnea peregra

(Acc. No. 070562). Based on these results, the cypermethrins can be categorized as very highly 

toxic on an acute basis. Taking the most conservative approach, the lowest LC50 value reported 

(96-hour LC50 value of 0.0036 μg a.i./L) is used to evaluate acute toxic exposure of freshwater 

invertebrates to cypermethrin.

Studies assessing the acute toxicity of three cypermethrin formulations to daphnids were 

submitted. The formulations tested were GFU 034/A (36% a.i.), GFU 061 (36% a.i.), and GFU 

070 (24% a.i.). Results of these studies were reported as EC50 values (for immobility), rather 

than LC50 values. The 48-hour EC50

 12 60-d EEC of 0.131 μg a.i./L (based on North Carolina Fruit and coarse droplets, from the RED) ÷ estimated 

saltwater NOAEC (0.34 μg a.i./L, see calculations above) = 0.4.

values ranged from 1.56 μg a.i./L (MRID 62793) to 21.6 
40

μg a.i./L (MRID 89040), indicating that these formulations are very highly toxic to freshwater 

invertebrates on an acute basis. Comparison of the 48-hour LC50/EC50 values for cypermethrin 

TGAI (0.42 to 2.0 μg a.i./L) and cypermethrin formulations (1.56 to 21.6 μg a.i./L) indicates that 

the formulated products have a similar order of toxicity to technical grade cypermethrins.

Acute toxicity tests in freshwater invertebrates using the cypermethrins degradate 3-

phenoxybenzoic acid to daphnids were also submitted. Results yield 48-hour EC50 values of 

89.0 mg degradate/L (MRID 152739) and 111 mg degradate/L (Acc. No. 070562). Based on 

these acute toxicity values, 3-phenoxy benzoic acid is categorized as practically non-toxic to 

slightly toxic to freshwater invertebrates on an acute basis. Thus, the 3-phenoxy benzoic acid 

degradate is much less toxic than the cypermethrins TGAI to freshwater invertebrates.

No valid chronic toxicity studies on the technical grade cypermethrins in freshwater invertebrates 

were submitted. The previous RED calculated acute-to-chronic ratios based on available acute 

toxicity data based on the following mathematical relationship:

Estuarine/marine invertebrate LC50 (0.00475μg a.i./L) / Estuarine/marine invertebrate 

NOAEC (0.000781μg a.i./L) = Freshwater invertebrate LC50 (0.42 μg a.i./L)/ X 

(estimated value for Freshwater invertebrate NOAEC), where X = 0.069 μg a.i./L. 

Chronic studies are triggered in several ways per 40 CFR Par 158, including, the direct 

applications to water for the cattle livestock use, EECs > 0.1 of the LC/EC50

13 bioconcentration 

potencial (BCF of 448x, MRID 42868203) and half-life of > 4 days in water (8.9-10.1 days, 

MRID 45920801). No chronic toxicity studies for the formulations or degradates of the 

cypermethrins in freshwater invertebrates were submitted. This is identified as a data gap. 

Estuarine/Marine Invertebrates

Acute toxicity tests with estuarine/marine invertebrates using the cypermethrin TGAI were 

conducted in shrimp, molluscs, and crustaceans. Toxicity values (EC50 and LC50) reported for 

shrimp range from the 96-hour LC50 value of 0.00475 μg a.i./L (Acc. No. 070562) to the 96-hour 

LC50 value of 0.01 μg a.i./L (MRID 41068003). Similar results were observed in lobster (96-

hour LC50 = 0.04 μg a.i./L; MRID 41068003) and fiddler crab (96-hour LC50 = 0.197 μg a.i./L; 

MRID 89045). Based on these results, the cypermethrins TGAI is categorized as very highly 

toxic to estuarine/marine shrimp and crustaceans. Results of acute toxicity tests in molluscs 

show that the cypermethrins TGAI is moderately to highly toxic in oysters, with a 96-hour EC50

value of 0.37 mg a.i./L in Eastern oyster (MRID 89049) and a 48-hour LC50 value of >2.27 mg 

a.i./L in Pacific oyster (Acc. No. 070562). Results of these studies indicate that molluscs are less 

susceptible than shrimp and crustaceans to the cypermethrins toxicity on an acute basis. Taking 

the most conservative approach, the 96-hour LC50

 13 21-d EEC of 0.256 μg a.i./L (based on North Carolina Fruit and coarse droplets, from the RED) ÷ estimated 

freshwater NOAEC of 0.069 μg a.i./L (see calculations above) = 3.7.

value of 0.00475 μg a.i./L in mysid shrimp 

will be used to categorize acute risk to estuarine/marine invertebrates. No acute toxicity studies 

for the formulations or degradates of the cypermethrins in estuarine/marine invertebrates were 
41

submitted. This is identified as a data gap. 

Three studies involving life-cycle tests in mysid shrimp were submitted by the registrant to 

establish the chronic toxicity of cypermethrin to estuarine/marine invertebrates. The NOAEC 

values reported in these studies range from 0.781 ng a.i./L for effects on first generation 

mortality, male length and weight and female weight (MRID 42725301), to 1.5 ng a.i./L for 

number of offspring (Acc. No. 070562) and survival and reproduction (MRID 44546035). 

Taking the most conservative approach, the lowest NOAEC value of 0.781 ng a.i./L will be used 

to characterize chronic risk to estuarine/marine invertebrates. No chronic toxicity studies for the 

formulations or degradates of the cypermethrins in estuarine/marine invertebrates were 

submitted. This is identified as a data gap. 

Benthic Organisms

Several studies on the toxicity of cypermethrin TGAI to benthic organisms have been submitted. 

Studies were conducted using two types of experimental protocols, exposure in a water-only 

system and exposure in a water-sediment system. In the water system studies, organisms were 

exposed to cypermethrin in overlying (surface) water; no sediment was present in the test 

chamber (these studies are discussed with the freshwater invertebrate studies above). For studies 

conducted using the water-sediment system protocol, cypermethrin was applied to watersediment systems and allowed to settle for 2 days; organisms were introduced to the above 

water-sediment systems, and toxicity was assessed after a 10-day exposure period. However, 

these studies present a degree of uncertainty because of the lack of equilibration of spiked 

sediments with the pore water (e.g., equilibration should have occurred for at least one month). 

While compounds bound to the sediment present potential toxicity concerns, those residues that 

have reached equilibrium in the pore water are considered a greater source of toxic risk to 

benthic invertebrates (Di Toro et al., 1991). Therefore the studies presented in this assessment 

may underestimate sediment toxicity. 

Two studies on cypermethrin TGAI were conducted using a water-sediment system, one study 

with midge (MRID 44074402) and one study with amphipod (MRID 44074406). Both studies 

were conducted using the same protocol, as described above, using sediments from three sources 

(Florissant, Mississippi, and Duluth). All toxicity values for these studies are expressed in terms 

of the concentration of cypermethrin in sediment (μg a.i./kg) on Day 0. Measurement of 

cypermethrin in sediment and surface water on Days 0 and 10 of exposure indicates that the 

water-sediment system was not at equilibrium, thus adding uncertainty to the results of these 

studies. Results yield 10-day LC50 values ranging from 3.6 μg a.i./kg sediment (Florissant 

sediment) in amphipods to 67 μg a.i./kg sediment in midge (Mississippi sediment). In general, 

toxicity decreased (as reflected by higher LC50 values), with increasing organic carbon content 

of the sediment. Taking the most conservative approach, the lowest 10-day LC50 value of 3.6 μg 

a.i./kg sediment in amphipods will be used to characterize the risk of acute exposure of benthic 

organisms to the cypermethrins TGAI in sediment.
42

In order to assess the risk of acute exposure to benthic organisms to the cypermethrins TGAI 

based on pore water concentrations, the equivalent toxicity value in pore water is derived using 

the lowest 10-day LC50 value of 3.6 μg a.i./kg sediment in amphipods. The LC50 value in whole 

sediment [3.6 μg a.i./kg sediment] is divided by the proportion of organic carbon (OC) in the 

sediment [0.0099 kg OC/kg whole sediment]. Thus, the LC50 value in units of OC is 364 μg 

a.i./kg OC [3.6μg a.i./kg sediment ÷ 0.0099 kg OC/kg sediment]. The equivalent concentration 

in pore water is based on the definition of the Koc,

Koc (L/kg OC) = [sediment (mg/Kg OC)] / [pore water (mg/L)]

By rearrangement,

[water] = [sediment (mg/Kg OC)] / Koc

For the cypermethrins, the Koc is 141,700 [L/kg OC] (MRID 42129003). Thus, the calculated 

concentration in pore water corresponding to the LC50 value of 364 μg a.i./kg OC is 0.00257 μg 

a.i./L [364 μg a.i./kg OC ÷ 141,700 L/kg OC]. To assess risk of acute exposure to benthic 

organisms to cypermethrin TGAI in terms of pore water concentrations, the derived LC50 value 

of 0.00257 μg a.i./L is used.

No toxicity studies for the formulations or degradates of the cypermethrins in freshwater benthic 

organisms were submitted. This is identified as a data gap. 

Chronic toxicity studies in benthic organisms were not submitted. To assess chronic risk to 

benthic organisms, chronic toxicity values were derived for both sediment and pore water. The 

previous RED calculated acute-to-chronic ratios based on available acute toxicity data based on 

the following mathematical relationships:

Estuarine/marine invertebrate LC50 (0.00475μg a.i./L) / Estuarine/marine invertebrate 

NOAEC (0.000781μg a.i./L) = Benthic LC50 in sediment 3.6 μg a.i./kg sediment / X 

(estimated benthic NOAEC value in sediment), where X = 0.59 μg a.i./kg sediment. 

Estuarine/marine invertebrate LC50 (0.00475μg a.i./L) / Estuarine/marine invertebrate 

NOAEC (0.000781μg a.i./L) = Benthic LC50 in pore water (0.00257 μg a.i./L / X 

(estimated benthic NOAEC value in pore water ), where X = 0.00042 μg a.i./L pore 

water. To assess chronic risk to benthic organisms, the estimated NOAEC values of 0.59 

μg a.i./kg sediment and 0.00042 μg a.i./L pore water are used.

No chronic toxicity studies for the formulations or degradates of the cypermethrins in freshwater 

benthic organisms were submitted. This is identified as a data gap. 

4.1.3 Plants

No studies evaluating the toxicity of the cypermethrins to terrestrial plants, aquatic plants or 
43

algae have been submitted to the Agency. This is identified as a data gap.

ECOTOX

Iin additiona to submitted data, available open literature will be used to evaluate the potential 

direct effects of cypermethrin to the terrestrial receptors identified in this section. This includes 

toxicity data on the technical grade active ingredient, and when available, formulated products. 

At this time, a full and complete ECOTOX search has not been performed, but will be conducted 

prior to the final risk assessment. The open literature studies will be identified through EPA’s 

ECOTOX database (http://cfpub.epa.gov/ecotox/), which employs a literature search engine for 

locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of 

data can also provide insight into the direct and indirect effects of cypermethrin on biotic 

communities from loss of species that are sensitive to the chemical and from changes in structure 

and functional characteristics of the affected communities. 

Open literature toxicity data for other ‘target’ insect species (not including bees, butterflies, 

beetles, and non-insect invertebrates including soil arthropods and worms), which include 

efficacy studies, are not currently considered in deriving the most sensitive endpoint for 

terrestrial insects. Efficacy studies do not typically provide endpoint values that are useful for 

risk assessment (such as NOAEC, EC50, etc.), but rather are intended to identify a dose that 

maximizes a particular effect (such as EC100). Therefore, efficacy data and non-efficacy 

toxicological target insect data will not be included in the ECOTOX open literature search. 

4.2 Incident Database Review 

A review of the Ecological Incident Information System (EIIS, v. 2.1) and Aggregate Incident 

databases for ecological incidents involving cypermethrin and zeta-cypermethrin was completed 

on December 8, 2011. This database consists of exposure incident reports submitted to the EPA 

from 1994 to present. A search for incidents involving cypermethrin and zeta-cypermethrin was 

also conducted in the American Bird Conservancy’s Avian Incident Monitoring System (AIMS). 

The reports are listed in order of certainty, from highly probable to unrelated. Incidents listed in 

EIIS are categorized by the likelihood that a particular pesticide is associated with that particular 

incident. These classifications include highly probable, probable, possible, unlikely or unrelated. 

“Highly probable” incidents usually require carcass residues or clear circumstances regarding the 

exposure. “Probable” incidents include those where residue information was not available or 

circumstances were less clear than those for “highly probable”. “Possible” incidents occur when 

multiple chemicals may have been involved and the contribution of an individual chemical is not 

obvious. An “unlikely” incident classification is given when a given chemical is considered 

nontoxic to the type of organism involved or the chemical was analyzed and not detected in 

samples. The “unrelated” category is used for incidents confirmed not to involve pesticides. 

The number of reports listed in the EIIS database is believed to be only a small fraction of the 

total incidents involving organism mortality and damage caused by pesticides. Few resources are 

assigned to incident reporting. Reporting by states is only voluntary, and individuals discovering 
44

incidents may not be informed on the procedure of reporting these occurrences. Additionally, 

much of the database is generated from registrant-submitted incident reports. In addition, 

incident reports for non-target organisms typically provide information only on mortality events 

and plant damage incidents. Except for phytotoxic effects in terrestrial plants, sublethal effects 

for organisms such as reduced growth or impaired reproduction are rarely reported. Because of 

these logistical difficulties, EIIS is most likely a minimal representation of all pesticide-related 

ecological incidents.

Registrants are legally required to provide detailed reports of only “major” ecological incidents 

involving pesticides, while “minor” incidents are reported aggregately. Based on 40 CFR 

§159.184, an ecological incident is considered major and must be submitted to the Agency by the 

registrant if any of the following criteria are met:

Fish or wildlife:

(A) Involves any incident caused by a pesticide currently in Formal Review14

(B) Fish: Affected 1,000 or more individuals of a schooling species or 50 or more 

individuals of a non-schooling species. 

for 

ecological concerns. 

(C) Birds: Affected 200 or more individuals of a flocking species, or 50 or more 

individuals of a songbird species, or 5 or more individuals of a predatory species. 

(D) Mammals, reptiles, amphibians: Affected 50 or more individuals of a 

relatively common or herding species or 5 or more individuals of a rare or solitary 

species. 

(E) Involves effects to, or illegal pesticide treatment (misuse) of a substantial tract 

of habitat (greater than or equal to 10 acres, terrestrial or aquatic). 

Plants: 

(A) The effect is alleged to have occurred on more than 45 percent of the acreage 

exposed to the pesticide.

The EIIS database contained 22 major incidents involving the cypermethrins. The reports 

included 15 fish incidents and 2 avian incidents, 3 mammalian incidents, and 2 terrestrial 

invertebrate incidents. In respect to the likelihood that cypermethrin caused the reported 

incidents, the certainty ranged from unlikely to highly probable. The majority of reported 

incidents were identified as probable or highly probable. Four of the incidents resulted from 

registered uses, seven were misuses and the remaining use patterns are unknown. A summary of 

ecological incidents involving cypermethrin included in the EIIS database are listed in Appendix 

B.

The AIMS database contains 2 avian incidents involving the cypermethrins, both of which 

are also captured in EIIS.

All other incidents are classified as ‘minor’. All ecological incidents classified as ‘minor’ only 

 14 Formal Review means Special Review, Rebuttable Presumption Against Registration (RPAR), FIFRA 

section 6(c) suspension proceeding, or FIFRA section 6(b) cancellation proceeding, whether completed or 

not.
45

need to be aggregately reported as quarterly counts of incidents by the registrant(s). Ecological 

incidents reported in aggregate reports include those categorized as ‘minor fish and wildlife’ (WB), ‘minor plant’ (P-B), and ‘other non-target’ (ONT) incidents. ‘Other non-target’ incidents 

include reports of adverse effects to insects and other terrestrial invertebrates. For the 

cypermethrins, the registrants have reported 21 minor fish and wildlife incidents, 4 minor 

plant incidents, and 1 “other non-target” incdent. All reported incidents occurred between 

1995 and 2010, and involved currently registered products such as Demon WP, Cyper TC 

Insecticide, Prevail TC Termiticide, Probuild TC, Demon Max, among others. Unless additional 

information on these aggregated incidents becomes available, they will be assumed to be 

representative of registered uses of the cypermethrins in the risk assessment.

4.3 Ecosystems Potentially at Risk 

The cypermethrin may be applied on a variety of food/feed crops, including (but not limited to),

alfalfa, nut trees, corn, leafy vegetables, stone fruits, pome fruits, fruiting vegetables, cucurbit 

vegetables, cole crops, onion and soybean. In addition, they may be used on numerous non-food 

sites (e.g. ornamentals, commercial animal housing, outdoor agricultural premises, residential 

sites – outdoors, and outdoor eating establishments) and indoor sites (e.g. residential sitesindoors, food handling premises, eating establishments-indoors, and transporation facilities). 

Thus, the ecosystems at risk may be extensive in scope, and as a result it may not be possible to 

identify specific ecosystems during the development of a baseline risk assessment. In general 

terms, terrestrial ecosystems potentially at risk due to the use of the cypermethrins could include 

the treated field and areas immediately adjacent to the treated field that may receive drift or 

runoff. Areas adjacent to the treated field could include cultivated fields, fencerows and 

hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats and other 

uncultivated areas. Current label directions for the cypermethrins require vegetative buffer strips 

and impose limitations to reduce the potential for spray drift to impact areas adjacent to the 

treated field. However, due to the potential persistence of the cypermethrins under certain 

circumstances, it is expected to drift and/ or runoff due to application to food crops and certain 

non-crop sites, resulting in possible exposure to aquatic ecosystems. In addition, indoor use 

patterns of the cypermethrins could result in “down-the-drain” exposure to aquatic ecosystems 

that receive treated waters. Aquatic ecosystems potentially at risk due to the use of the 

cypermethrins include water bodies adjacent or downstream from the treated field and might 

include impounded bodies such as ponds, lakes and reservoirs, or flowing waterways such as 

streams or rivers. For uses in coastal areas, aquatic habitat also includes marine ecosystems, such 

as estuaries. 

5 Assessment Endpoints

Assessment endpoints are defined as “explicit expressions of the actual environmental value that

is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the 

valued attributes of the environment that are considered to be at risk; and 2) operationally 

defining the assessment endpoint in terms of an ecological entity (i.e., a community of fish and 

aquatic invertebrates) and its attributes (i.e., survival and reproduction). Therefore, selection of 
46

the assessment endpoints is based on valued entities (i.e., ecological receptors), the ecosystems 

potentially at risk, the migration pathways of pesticides, and the routes by which ecological 

receptors are exposed to pesticide-related contamination. The selection of clearly defined 

assessment endpoints is important because they provide direction and boundaries in the risk 

assessment for addressing risk management issues of concern. Changes to assessment endpoints 

are typically estimated from the available toxicity studies, which are used as the measures of 

effects to characterize potential ecological risks associated with exposure to pesticides, such as 

the cypermethrins.

To estimate exposure concentrations, the ecological risk assessment considers applications at the 

maximum application rate to fields that have vulnerable soils. The most sensitive toxicity 

endpoints are used from surrogate test species to estimate treatment-related direct effects on 

acute mortality and chronic reproductive, growth and survival assessment endpoints. Toxicity 

tests are intended to determine effects of pesticide exposure on birds, mammals, fish, terrestrial 

and aquatic invertebrates, and plants. These tests include short-term acute, sub-acute, and 

reproduction studies and are typically arranged in a hierarchical or tiered system that progresses 

from basic laboratory tests to applied field studies. The toxicity studies are used to evaluate the 

potential of a pesticide to cause adverse effects, to determine whether further testing is needed, 

and to determine the need for precautionary label statements to minimize the potential adverse 

effects to non-target animals and plants.

An open literature search will be conducted to determine any relevant endpoints. The search will 

focus on survival, growth and reproductive effects for aquatic and terrestrial effects of the 

cypermethrins. More sensitive endpoints from acceptable open literature studies will be included 

in the ecological risk assessment.

6 Conceptual Model

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves in the 

environment from a source to an ecological receptor. For an ecological pathway to be complete, 

it must have a source, a release mechanism, an environmental transport medium, a point of 

exposure for ecological receptors, and a feasible route of exposure.

A conceptual model provides a written description and visual representation of the predicted 

relationships between cypermethrin, potential routes of exposure, and the predicted effects for 

the assessment endpoint. A conceptual model consists of two major components: risk hypothesis 

and a conceptual diagram (USEPA, 1998).

6.1 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 (USEPA 1998). For this assessment, the risk is stressor-initiated, 

where the stressor is the release of the cypermethrins into the environment. The following risk 
47

hypotheses are presumed for this screening-level assessment:

The cypermethrins, when used outdoors in accordance with registered labels, will likely 

lead to off-site movement of the compound via agricultural and urban runoff, spray drift, 

and eroded soil leading to exposure of nontarget plants and animals Based on 

information on the environmental fate, mode of action, direct toxicity and potential 

indirect effects, EFED assumes that registered uses of the cypermethrind have the 

potential to cause reduced survival, growth, and reproduction to non-target terrestrial 

and/ or aquatic animals and plants.

The cypermethrins, when used indoors for uses such as pet shampoos, etc., in accordance 

with current labels, will likely result in off-site movement of the compound via wash-off 

into surface waters via drains and municipal wastewater treatment plants, leading to 

exposure of nontarget aquatic plants and animals. This potential exposure pathway may 

result in adverse effects upon the survival, growth, and/or reproduction of non-target 

aquatic animals and plants. 

The cypermethrins, when used for the treatment of cattle (and certain other animals), in 

accordance with current labels, may result in off-site movement of the compound via 

wash-off of cattle and calves into surface waters, leading to exposure of nontarget 

aquatic plants and animals. This potential exposure pathway may result in adverse 

effects upon the survival, growth, and/or reproduction of non-target aquatic animals and 

plants.

The conceptual model is a generic graphic depiction of the risk hypothesis. It includes the 

potential pesticide or stressor (the cypermethrins and possible metabolites, as well as synergists), 

the source of the pesticide and/or transport pathways, exposure media, exposure point, biological 

receptor types, and attribute changes.

6.2 Conceptual Diagram

The conceptual model is a generic graphic depiction of the risk hypothesis, and assumes that the 

cypermethrins, which are synthetic pyrethroid insecticide, having multiple outdoor agricultural 

and non-agricultural uses, is capable of affecting aquatic and terrestrial animals provided that 

environmental concentrations are sufficiently elevated as a result of proposed label uses. Based 

on an examination of the physicochemical properties of the cypermethrins, the fate and 

disposition in the environment, and mode of application, a conceptual model was developed that 

represents the possible relationships between the stressors, ecological receptors, and the 

assessment endpoints. Through a preliminary iterative process of examining available data, the 

conceptual model (i.e., the representation of the risk hypothesis) may be refined to reflect the 

likely exposure pathways and the organisms that are most relevant and applicable to this 

assessment (Figures 6-1a and 6-1b). They include the potential pesticide or stressor (the 

cypermethrins, but the presence of toxicologically important metabolites and/ or synergists 

cannot be ruled out), the sources and/ or transport pathways, exposure media and exposure 

points, biological receptor types and attribute changes.
48

In order for a chemical to pose an ecological risk, it must reach ecological receptors in 

biologically significant concentrations. An exposure pathway is the means by which a pesticide 

moves in the environment from a source to an ecological receptor. For an ecological exposure 

pathway to be complete, it must have a source, a release mechanism, an environmental transport 

medium, a point of exposure for ecological receptors, and a feasible route of exposure. In 

addition, the potential mechanisms of degradation/ transformation (i.e., which degradation/ 

transformation products may form in the environment, in which media, and how much) must be 

understood, especially if for the chemical, its metabolites/ transformation products are of greater 

toxicological concern than the parent compound. The assessment of ecological exposure 

pathways, therefore, includes an examination of the source and potential migration pathways for 

constituents, and the determination of potential exposure routes.

Under the possible uses of the cypermethrins, the sources and mechanisms of release of the 

compounds are from ground or aerial spray or ULV applications. Note that this conceptual 

model considers agricultural applications as well as certain non-agricultural applications. 

Surface runoff from the areas of application is assumed to depend on factors such as topography, 

irrigation, and rainfall events. Direct deposition may result in contamination of food items that 

may be consumed by terrestrial organisms. Spray drift results in contaminated adjacent areas, 

including bodies of water. Leaching to groundwater is not considered an important source 

because the cypermethrins, like many other pyrethroids, show low mobility in a variety of soils. 

The cypermethrins appear to have a low potential for volatilization, with a low vapor pressure 

and Henry’s Law Constants. The low vapor pressure (~10-9

torr) and relatively low Henry’s Law 

constant (~10-7 atm/m3

-mol), and its binding capacity, suggest that the potential for atmospheric 

transport for the cypermethrins is relatively low and that this source of the chemical is of low 

importance, compared to spray drift, runoff and/ or direct contact after application.

For aquatic receptors, the major point of exposure is through direct contact with the water 

column, sediment, and pore water (gill/ integument) contaminated with spray drift (from spray 

application) and/or runoff and flow (e.g., piped storm drains) from treated areas. Indirect effects 

to aquatic organisms (both fish and aquatic invertebrates) can also occur through impact to 

various food chains. The representative aquatic receptors are certain freshwater and estuarine/ 

marine fish, invertebrates, and, in certain cases, aquatic plants. The major point of exposure for 

terrestrial animals is consumption of food contaminated with residues such as grass, foliage, and 

small insects. For plants, the point of exposure is direct contact or root uptake. The 

representative terrestrial receptors are mammals, birds and terrestrial plants. The attribute 

changes used to assess risk to terrestrial receptors depend on the type of test (e.g., reduced 

survival, growth, or reproduction for animals and seedling emergence and vegetative vigor for 

plants). It should be noted, that these species do not cover all the possible species in the animal 

and plant kingdoms; certain taxa are considered as surrogates for other taxa. For example, fish 

are considered surrogates for aquatic phase amphibians.

This conceptual model also shows information about the potential for biomagnification for the 

cypermethrins (see piscivorous birds and mammals in Fig. 6-1b). The reported value of log 

octanol/ water partition coefficient of 6.4 suggests that the cypermethrins have the potential to 

bioaccumulate in aquatic organisms assuming that chemical metabolism is negligible. Maximum 
49

BCFs for the cypermethrins are 161x for edible tissue, 883x for viscera, and 448x for whole fish. 

Depuration appeared to be moderately slow, with ~10-15% of the initial residues remaining after 

21 days. Thus, it appears that there is potential for bioaccumulation/ bioconcentration in aquatic 

organisms and biomagnification in terrestrial organisms.

The cypermethrins have a solubility of 4.0 ppb and a very high KOW. These properties suggest 

that the chemicals could partition with the sediments and particulate suspended in bodies of 

water. The cypermethrins are likely to concentrate in the sediments, especially after repeated 

exposures (applications), where they could persist. Such sediments could serve as repositories of 

the chemicals for extended periods of time and could potentially be toxic to sediment dwelling 

organisms, affecting the food chain. These issues will also be assessed in the risk assessment for 

the cypermethrins.

Figure 6-1a. Aquatic conceptual model depicting stressors, exposure pathways, and 

potential effects to aquatic organisms from the use of the cypermethrins on agricultural 

and certain non-agricultural sites 

1

**Considered a minor route of exposure

Includes flow across vegetation and vegetated drainage systems (e.g., swales) and flow across impervious surfaces 

and through impervious (piped) storm drains.

Stressor

Source

Receptors

Attribute

Change

Cypermethrins applied to agricultural or non-agricultural use 

site

Spray drift

Aquatic animals

Invertebrates 

Vertebrates

Piscivorous mammals 

 and birds** 

Individual organisms

Reduced survival (2)

Reduced growth

Reduced reproduction

Food chain

Reduction in algae and 

 vascular plants

Reduction in prey

Modification of PCEs 

 related to prey availability

Habitat integrity

Reduction in primary 

 productivity

Reduced cover

Community change

Modification of PCEs related to 

 habitat

Surface water/

Sediment

Runoff

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Uptake/gills 

or integument

Ingestion Ingestion

Atmospheric 

transport

Wet/dry deposition

Soil Leaching to

Groundwater

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake/cell, 

roots, leaves Riparian plants

terrestrial 

exposure

pathways; see 

Figure 6.1b

Impervious 

Surfaces

Flow (1)
50

2 Immobilization is considered equivalent to mortality in toxicity tests for aquatic invertebrates.

Dotted lines indicate exposure pathways that have a low likelihood of contributing to ecological risk.

Figure 6-1b. Terrestrial conceptual model depicting stressors, exposure pathways, and 

potential effects to terrestrial organisms from the use of the cypermethrins on agricultural 

and certain non-agricultural sites 

Dotted lines indicate exposure pathways that have a low likelihood of contributing to ecological risk. 

1 Includes flow across vegetation and vegetated drainage systems (e.g., swales) and flow across impervious surfaces

and through impervious (piped) storm drains.

The conceptual model for potential risks of the cypermethrins to aquatic organisms due to

various indoor uses of the chemical that could potentially end up in a “drain” and disposed 

through domestic wastewater is depicted in Fig. 6-2. The stressors are the chemicals of concern,

the cypermethrins. It is noted that the transport pathway is wastewater flow, the exposure media 

is the treatment facility and the exposure route, receptor, and attribute changes for aquatic 

organisms are similar to the conceptual model for agricultural applications.

EFED will perform an assessment of the “down-the-drain” uses, using available usage 

information and new endpoints (if any are developed, from newly submitted studies) in the 

Stressor

Source

Attribute

Change

Cypermethrins applied to agricultural or non-agricultural use sites

Direct

application Spray drift

Terrestrial 

vertebrates

Terrestrial 

invertebrates

Individual 

organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey and food

Modification of PCEs 

 related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related

 to habitat

Terrestrial plants

grasses/ forbs, fruit, seeds 

(trees, shrubs)

Runoff

Terrestrial 

vertebrates 

Exposure Media 

& Receptors Soil

Ingestion

Ingestion

Ingestion

Dermal uptake/Ingestion

Atmospheric 

transport

Root uptake/contact

Wet/dry deposition

Ingestion

Leaching to

Groundwater Irrigation 

water Flow (1)
51

Registration Review ecological risk assessment.

Figure 6-2. Conceptual model for potential risks of the cypermethrins to aquatic 

organisms for various indoor uses of the chemical that could potentially end up in the 

“drain”

 

The conceptual model for potential risks of the cypermethrins to terrestrial and aquatic 

organisms as a result of the treatment on cattle or calves is depicted in Fig. 6-3. The stressors are 

the chemicals of concern, the cypermethrins, and potentially interactions caused by applications 

with the synergists PBO and MGK-264. The organisms that could be expected to be affected are 

terrestrial plants, aquatic plants and aquatic animals. It is noted that the potential transport 

pathway, the exposure media and the exposure point or route, receptor, and attribute changes for 

plant and aquatic organisms are similar to the conceptual model for agricultural applications Fig. 

6-1a.

Stressor Cypermethrins applications that could potentially end up “down-the-drain”

(i.e., pet spot on, furniture treatments, mopped surfaces)

Source/

Transport

Pathways

Domestic wastewater flow;

Partitioning with sewage sludge

Source/

Exposure

Media

Treatment facility 

discharges into surface 

waters

Exposure

Route

Gill/

Integument 

Uptake

Receptors

Attribute

Changes

Aquatic 

Invertebrates,

Vertebrates

Individual 

Vertebrates and 

Invertebrates

Reduced survival 

or reproduction

Plant Population

Reduced 

population 

growth

Aquatic 

Plants

Uptake/ 

Adsorption
52

Figure 6-3: Conceptual model for potential risks of the cypermethrins to aquatic 

organisms as a result of the treatment on cattle or calves. 

 

7 Analysis Plan 

In order to address the risk hypothesis, the potential for adverse effects on the environment is 

estimated. Usage, environmental fate and transport, and ecological effects of the cypermethrins

are characterized and integrated to assess the risks. This is accomplished using a risk quotient 

(ratio of exposure concentration to effects concentration) approach. Although risk is often 

defined as the likelihood and magnitude of adverse ecological effects, the risk quotient-based 

approach does not provide a quantitative estimate of likelihood and/ or magnitude of an adverse 

effect. However, as outlined in the Overview Document (USEPA 2004), the likelihood of 

effects to individual organisms from particular uses of a chemical is estimated using the probit 

dose-response slope and either the level of concern (discussed below) or the actual calculated 

risk quotient value. 

Stressor Cypermethrins and PBO used as for the treatment of cattle and other animals

(Immersion in surface water body or washoff transported nearby or to surface waters)

Source/

Transport

Pathways

Surface waters

Source/

Exposure

Media

Riparian/

Wetland 

Foliage/Soil Receiving Water Body/ 

Sediment

Exposure

Route

Direct Contact/

Root Uptake Gill/

Integument 

Uptake

Receptors

Attribute

Changes

Aquatic 

Invertebrates,

Vertebrates

Wetland/ 

Riparian

Plants

Individual Plants

Reduced survival, 

growth, or reproduction

Individual 

Vertebrates and 

Invertebrates

Reduced survival 

or reproduction

Plant Population

Reduced 

population 

growth

Aquatic 

Plants

Uptake/ 

Adsorption
53

This analysis plan will be revisited and may be revised depending on the data available in the 

open literature and the information submitted by the public or the registrant in response to the 

opening of the Registration Review docket.

7.1 Stressors of Concern

The focus of this assessment is on the parent materials, the cypermethrins. However, the Agency 

will review open literature to identify degradate(s) of potential toxicological concern (e.g. DCVA 

and 3-PBA). Also, risk resulting from use of the cypermethrins and synergists will be assessed 

for cattle treatments.

Toxicity data for environmental mixtures of the cypermethrins with other pesticides (those 

mixtures occurring in the environment following application), if available, may be presented as 

part of the ecological risk assessment. The cypermethrins may be applied in tank mixtures with 

other products approved for use on registered crops. It is expected that the toxic effect of the 

cypermethrins, in combination with other pesticides used in the environment, is likely to be a 

function of many factors including, but not necessarily limited to (1) the exposed species, (2) the 

co-formulants in the mixture, (3) the ratio of the cypermethrins and co-formulants 

concentrations, (4) differences in the pattern and duration of exposure among formulants, and (5) 

the differential effects of other physical/ chemical characteristics of the receiving waters (e.g.

organic matter present in sediment and suspended water). A discussion of implications of the 

available pesticide mixture effects data on the confidence of risk assessment conclusions will be 

addressed in the risk description of the final ecological assessment.

7.2 Measures of Exposure

In order to estimate risks of the cypermethrins exposures in aquatic and terrestrial environments, 

all exposure modeling and resulting risk conclusions will be made based on maximum 

application rates for the current use patterns. Available monitoring data will also be considered 

when describing potential environmental exposure to non-target organisms.

Measures of exposure are based on aquatic and terrestrial models that predict estimated 

environmental concentrations of the cypermethrins using maximum labeled application rates and 

methods, as well as any mitigation measures specifically indicated on the label. 

Additional information on the terrestrial exposure models and screening tools employed in EPA 

ecological risk assessments for pesticides can be found at 

http://www.epa.gov/oppefed1/models/terrestrial/.

More information on aquatic pesticide exposure models can be found at

http://www.epa.gov/oppefed1/models/water/index.htm.
54

Dietary exposure to terrestrial organisms

Measures of exposure for terrestrial mammals, birds, reptiles and amphibians similarly 

incorporate maximum proposed use rates but rely less on fate properties. Terrestrial exposures 

are estimated using a number of methods. For the cypermethrins, acute and chronic terrestrial 

exposure estimates are derived directly from empirically determined observations of pesticide 

residues on various terrestrial food items. The Kenaga nomogram, as modified by Fletcher et al, 

(Kenaga and Hoerger, 1972; Fletcher et al, 1994) is used to relate pesticide application rates to 

residues on terrestrial food items. 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. For numerous applications for a given use, the exposure model incorporates a firstorder decay rate dependent on the foliar dissipation half-life of the chemical. In the absence of 

foliar dissipation data, a default foliar dissipation half-life of 35 days is used.

Inhalation, drinking water and dermal exposure

Two screening tools were utilized to assess the potential for exposure of the cypermethrins to 

terrestrial organisms via inhalation and drinking water exposure. The Screening Tool for 

Inhalation Risk (STIR v.1.0, November 19, 2010) was used to calculate an upper bound estimate 

of exposure using vapor pressure and molecular weight of the cypermethrins for vapor phase 

exposure, as well as the maximum application rate and method of application for spray drift. 

STIR incorporates results from several toxicity studies including acute oral and inhalation rat 

toxicity (oral LD50 = 86 mg/kg-bw and LC50 >2.5 mg/L, respectively) as well as the most 

sensitive acute oral avian toxicity endpoint (bobwhite quail, LD50 > 2000 mg ai/kg bw). Based 

on the results of the STIR model, inhalation exposure alone was determined not to be a potential 

pathway of concern for avian and mammalian species on an acute basis. 

Inhalation exposure via spray drift and vapor-phase of the cypermethrins alone does not appear 

to be of concern. The analysis of the inhalation route of in STIR does not consider that 

aggregation with other exposure pathways such as dietary, dermal, or drinking water may 

contribute to a total exposure that has a potential for effects to non-target animals. However, the 

Agency does consider the relative importance of other routes of exposure in situations where 

data indicate that pesticide exposures through other routes may be potentially significant 

contributors to wildlife risk (US EPA, 2004).

The Screening Imbibition Program (SIP v.1.0, Released June 15, 2010) was used to calculate an 

upper bound estimate of exposure using the cypermethrins solubility (4.0x10-3 mg/L), the most 

sensitive acute and chronic avian oral toxicity endpoint (bobwhite quail, LD50 > 2000 mg ai/kg

bw and NOEL = 50 mg/kg-bw, respetively) and the most sensitive acute and chronic mammalian 

toxicity endpoints (oral LD50 = 86 mg/kg-bw and NOAEL = 5 mg/kg-bw, respectively). 

Drinking water exposure alone was determined not to be a potential pathway of concern for 

avian and mammalian species on an acute or chronic basis. 

Although drinking water exposure alone does not appear to be of concern, this does not take into 

account that when aggregated with other exposure pathways (dietary food sources, dermal, 

inhalation) drinking water may contribute to a total exposure that has a potential for effects on 
55

non-target animals and should be explored further. Because there is a high degree of 

conservatism in the SIP 1.0 exposure estimate, there is limited expectation that use scenarios not 

triggering a SIP 1.0 concern would contribute significantly to aggregate risks from water plus 

diet when a refined water exposure model is incorporated in the actual quantitative risk 

assessment.

Although not available at this time, the Agency is actively pursuing modeling techniques to 

account for dermal exposure via direct application of spray and by incidental contact with 

contaminated vegetation, soil and water.

Exposure to terrestrial plants

TerrPlant is used by EFED as a Tier 1 model for screening level assessments of pesticides. The 

purpose of TerrPlant is to provide screening level estimates of exposure to terrestrial plants from 

single pesticide applications. The model does not consider exposures to plants from multiple 

pesticide applications. TerrPlant derives pesticide EECs in runoff and in drift. RQs are 

developed for non-listed and listed species of monocots and dicots inhabiting dry and semiaquatic areas which are adjacent to treatment sites. Once suitable terrestrial plant data are 

submitted to the Agency, this model will be used to determine the potential risks to terrestrial 

plants following applications of the cypermethrins. 

Aquatic exposure modeling

The models used to predict aquatic EECs are the Pesticide Root Zone Model coupled with the 

Exposure Analysis Model System (PRZM/EXAMS). Also, to estimate aquatic exposure related 

to releases of the cypermethrins from domestic wastewater treatment plants, the Exposure and 

Fate Assessment Screening Tool’s (E-FAST2) down-the-drain module will be used. For the 

treatment of cattle, measures of exposure will be calculations assuming direct applications to 

water considering living habits of cattle livestock. 

PRZM (v.3.12.2, May 2005) and EXAMS (v.2.98.4.6, April 2005) are simulation models 

coupled with the input shell PE5.pl (August, 2007) to generate daily exposures and 1-in-10 year 

EECs of the cypermethrins, that may occur from spray drift and runoff to surface water bodies 

adjacent to application sites. PRZM simulates pesticide application, movement and 

transformation on an agricultural field and the resultant pesticide loadings to a receiving water 

body via runoff, erosion and spray drift. The EXAMS model simulates the fate of the pesticide 

and resulting concentrations in the water body. The standard scenario used for ecological 

pesticide assessments assumes application to a 10-hectare agricultural field that drains into an 

adjacent 1-hectare water body that is 2 meters deep (20,000 cubic meters volume) with no outlet. 

PRZM/ EXAMS is used to estimate screening-level exposure of aquatic organisms to the 

cypermethrins and/ or their transformation products, should they be of concern. The measure of 

exposure for aquatic species is the 1-in-10 year return peak or rolling mean concentration. The 

1-in-10 year peak is used for estimating acute exposures of direct effects to aquatic organisms. 

The 1-in-10-year 60-day mean is used for assessing chronic exposure to fish and aquatic-phase 

amphibians. The 1-in-10-year 21-day mean is used for assessing aquatic invertebrate chronic 

exposure.
56

At the present time, EFED considers the use of the impervious scenario (a PRZM modeling 

scenario) as the most suitable available modeling approach for simulating runoff from 

impervious surfaces such as roads, sidewalks, patios and parking lots. The PRZM impervious 

scenario may be used in the Tier 2 coupled aquatic models PRZM/EXAMS along with the

residential or other suitable scenario such as rights-of-way (ROW) to obtain EECs. The 

conceptual model for the residential scenario integrates simultaneous modeling of the individual 

use scenario with an impervious scenario. This approach assumes that no watershed is 

completely covered by either the 1⁄4 acre lot (the basis for the residential scenario) or 

undeveloped land (the basis for the ROW scenario) for residential and ROW use patterns; 

therefore, differential amounts of runoff will occur within the watershed. The impervious 

scenario was developed to represent the paved areas within a watershed not including roads, 

parking lots, sidewalks, and buildings outside the 1⁄4 acre lot (the 1⁄4 acre lot scenario accounts for 

impervious surfaces such as buildings within the represented area). By modeling a separate 

scenario for impervious surfaces, it is also possible to estimate that amount of exposure that 

could occur when the pesticide is oversprayed onto this surface. Using two scenarios in tandem 

requires post-processing of the modeled output in order to derive a weighted EEC that represents 

the contribution of both the pervious (i.e., residential and ROW scenarios) and the impervious 

surfaces.

In general, incorporation of impervious surfaces into the exposure assessment results in 

increasing runoff volume in the watershed, which tends to reduce overall pesticide exposure. For 

the purposes of risk assessment alternate assumptions for percent impervious surfaces, 

percentage of use site treated, and percentage of overspray may be considered in order to 

characterize the assumptions of the ecological risk assessment in the context of the individual 

exposure assessment and risk conclusions. For example, previously tested assumptions used in 

the endangered species assessments may be considered for characterization (i.e., 10% and 30% 

impervious surfaces, 10% lot treated, and 0%, 1% and 10% overspray) unless other relevant 

values can be determined (i.e., modeling may be completed for the impervious surface with 0%, 

1% and 10% overspray to provide lower and upper bound values). The results of these alternate 

modeling exercises may be discussed in the assessment.

Given the aquatic toxicity of the cypermethrins and their likelihood to occur in sediment, the 

Agency will also consider the potential exposures resulting from benthic/ sediment 

concentrations. Pore water concentrations are commonly used to predict toxicity of non-ionic 

substances in sediments and characterize exposure to organisms that spend time in or near 

sediments (Di Toro et al. 1991; US EPA 2002). PRZM/ EXAMS estimates 1-in-10-year peak 

and 21-day mean EECs for pore water.

To estimate exposure related to releases of the cypermethrins from domestic wastewater 

treatment plants, the Agency will rely on the Office of Pollution Prevention and Toxics (OPPT) 

model, Exposure and Fate Assessment Screening Tool (EFAST, version 2.0, or EFAST2, 2007). 

From this model, the Agency will use the “Down-the-Drain” module, which is designed for 

releases to domestic wastewater treatment. It is suitable for all the sources of cypermethrin that 

could potentially be exposed through a “down-the-drain” scenario (i.e., disposed through 

domestic wastewaters). The model provides screening level estimate concentrations of 
57

chemicals in surface water that may result from household uses and the disposal of consumer 

products into wastewater using a few simple input parameters (production volume and fraction 

of the chemical removed during wastewater treatment). At the present time, the Agency does not 

anticipate requiring a POTW treatability study but will include an analysis of the “down-thedrain” scenario using more refined production volume values provided by BEAD or the 

registrant and any new endpoints (if any), developed during Registration Review.

Since the cypermethrins have uses on rice, the screening-level Tier 1 Rice Model v.1.0 will be 

utilized to obtain estimated exposure concentrations (EECs) related to that use. The Tier I Rice 

Model v1.0 relies on an equilibrium partitioning concept to provide conservative estimates of 

environmental concentrations resulting from application of pesticides to rice paddies. When a 

pesticide is applied to a rice paddy, the model assumes that it will instantaneously partition 

between a water phase and a sediment phase. Among the assumptions of this model, the 

degradation of the pesticide and the mass transfer from the aqueous phase to the sediment are not 

considered. Also, volatilization and other dissipation processes are not considered. If LOCs are 

exceeded using the Tier 1 rice model, estimates may be made using a provisional model, 

Pesticides in Flooded Applications Model (PFAM), to better characterize the risk. However, 

PFAM is not yet approved for general use for calculating pesticide EECs by the Agency.

There are two possible scenarios whereby residues of the cypermethrins can enter the aquatic 

ecosystem due to treatment of cattle. First, multiple cattle that are treated with the cypermethrins

can directly enter a water body, and second, rainfall can cause washoff of residues of the 

cypermethrins to be transported from multiple treated cattle to water bodies via runoff. For these 

cases, surface water concentrations will be calculated using the maximum mass of the 

cypermethrins per animal, spilling into a standard farm pond of 1 ha area and 2 m depth or a 

volume of 2.0 x 107 L. Surface water EECs will be calculated utilizing a suitable program which 

considers the soil-water partition coefficient and the depth of the sediment layer, such as the 

KdCalc (v.1.0 10/02/02). Certain assumptions are required for these scenarios. For example, for 

the first scenario, 20 treated cattle may be assumed to enter the water and for the second 

scenario, a 1000 treated cattle feedlot may be assumed (USDA NASS data).15 A maximum of 

100% of the active ingredient is assumed to wash-off cow hide for pour on products.

Bioaccumulation

The potential for bioaccumulation for the chemical is assessed using the KABAM model, as well 

the results from bioconcentration in fish studies (e.g., the bioconcentration factors). This model

is parameterized using relevant reviewed registrant-submitted environmental fate and transport 

data.

As indicated in Table 3.1 and its associated text in Section 3, the cypermethrins appear to have

some potential to bioconcentrate in aquatic organisms and it appears that there is also some

potential to biomagnify in terrestrial organisms. The potential for bioaccumulation of the

cypermethrins will also be examined in the risk assessment. Because the cypermethrins have a 

fairly high KOW (2.0 x 105

 15

) and the chemical may be persistent in water (aqueous photolysis 

http://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/Cattle_On_Feed/index.asp (accessed 02/01/11) 

“Feedlots with 1,000 or more head capacity represent about 85 percent of all fed cattle in the U.S.”
58

half-life of 36.2 days) and sediments (>10 days of aquatic metabolism), there could be a potential 

for bioaccumulation. The maximum bioconcentration factor is 448x for whole fish and the 

depuration rate is fairly slow (MRID 42868203). Bioaccumulation will be assessed using the 

results from bioaccumulation in fish studies, as well as the KABAM model (KOW

7.3 Measures of Effect

(based) 

Aquatic BioAccumulation Model, version 1.0, 2009), adjusting for biotransformation rates. 

KABAM is used to estimate potential bioaccumulation of hydrophobic organic pesticides in 

freshwater aquatic ecosystems and risks to mammals and birds consuming aquatic organisms 

which have bioaccumulated these pesticides. Monitoring data and biotransformation rates in 

terrestrial species will also be evaluated, to assess the potential for bioaccumulation in terrestrial 

food webs.

Ecological effects data are used as measures of direct and indirect effects to biological receptors. 

Data are typically obtained from registrant-submitted studies or from literature studies identified 

by ECOTOX. The ECOTOX database provides more ecological effects data in an attempt to 

bridge existing data gaps. ECOTOX is a source for locating single chemical toxicity data and 

potential chemical mixture toxicity data for aquatic life, terrestrial plants, and wildlife.

ECOTOX was created and is maintained by the USEPA, Office of Research and Development, 

and the National Health and Environmental Effects Research Laboratory's Mid-Continent 

Ecology Division.

The acute measures of effect used for animals in this assessment are the LD50, LC50 and EC50. 

LD stands for "Lethal Dose", and LD50 is the amount of a material, given all at once, that is 

estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration” 

and LC50 is the concentration of a chemical that is estimated to kill 50% of the test organisms. 

EC stands for “Effective Concentration” and the EC50 is the concentration of a chemical that is 

estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic 

measures of exposure for listed and non-listed animals are the NOAEL/NOAEC and NOEC. 

NOAEL stands for “No Observed-Adverse-Effect-Level” and refers to the highest tested dose of 

a substance that has been reported to have no harmful (adverse) effects on test organisms. The 

NOAEC (i.e., “No-Observed-Adverse-Effect-Concentration”) is the highest test concentration at 

which none of the observed effects were statistically different from the control. For non-listed 

plants, only acute exposures are assessed (i.e., EC25 for terrestrial plants and EC50 for aquatic 

plants); for listed plants either the NOAEC or EC05 is used.

At the time of the risk assessment, updated information on the potential effects of the 

cypermethrins on non-target animals will also collected from the Ecological Incident Information 

System (EIIS), Aggregrate Incident Reports and the Avian Monitoring Information System 

(AIMS). 

Where available, sub-lethal effects observed in both registrant-submitted and open literature 

studies will be evaluated qualitatively. Such effects may include behavioral changes (e.g., 

lethargy and changes in coloration). Quantitative assessments of risks, though, are limited to 

those endpoints that can be directly linked to the Agency’s assessment endpoints of impaired 

survival, growth and reproduction.
59

The assessment of risk for direct effects to non-target organisms makes the assumption that the 

toxicity of cypermethrin to birds is similar to that of the cypermethrins’ toxicity toterrestrialphase amphibians and reptiles. The same assumption is made for fish and aquatic-phase 

amphibians. 

7.4 Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effects to determine the 

potential ecological risk from the use of pesticides and the likelihood of direct and indirect 

effects to non-target organisms in aquatic and terrestrial habitats. The exposure and toxicity 

effects data are integrated in order to evaluate the risks of adverse ecological effects on nontarget species. For the assessment of risks, the risk quotient (RQ) method is used to compare 

exposure and measured toxicity values. EECs are divided by acute and chronic toxicity values. 

The resulting RQs are then compared to the Agency’s Levels of Concern (LOCs) (USEPA 

2004). These criteria will be used to indicate when cypermethrin uses, as directed on the label, 

have the potential to cause adverse direct or indirect effects to non-target organisms. In addition, 

incident data from the EIIS will be considered as part of the risk characterization.

7.5 Deterministic and Probabilistic Assessment Methods

The quantitative assessment of risk will primarily depend on the deterministic point-estimate 

based approach described in the risk assessment. An effort may also be made to further 

qualitatively describe risk using probabilistic tools that the Agency has developed. These tools 

have been reviewed by FIFRA Scientific Advisory Panels 

(http://www.epa.gov/scipoly/sap/index.htm) and have been deemed as appropriate means of 

refining assessments where deterministic approaches have identified risks.

7.6 Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to Federally-listed threatened and/or endangered (listed) species from 

registered uses of the cypermethrins. This assessment will be conducted in accordance with the 

Overview Document (USEPA 2004), provisions of the ESA, and the Services’ Endangered 

Species Consultation Handbook (USFWS/NMFS, 1998).

The assessment of effects associated with the registration of the cypermethrins are 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 exceedance of Agency LOCs used to evaluate direct or indirect 

effects. The Agency’s approach to defining the action area under the provisions of the Overview 

Document (USEPA 2004) considers the results of the risk assessment process to establish 

boundaries for that action area with the understanding that exposures below the Agency’s 

defined LOCs constitute a no-effect threshold. For the purposes of this assessment, attention 

will be focused on the footprint of the action (i.e., the area where cypermethrin application 
60

occurs), plus all areas where offsite transport may result in potential exposure that exceeds the 

Agency’s LOCs. Specific measures of ecological effect that define the action area for listed 

species include any direct and indirect effects and/ or potential modification of its critical habitat, 

including reduction in survival, growth, and reproduction as well as the full suite of sub-lethal 

effects available in the effects literature. Therefore, the action area extends to a point where 

environmental exposures are below any measured lethal or sub-lethal effect threshold for any 

biological entity at the whole organism, organ, tissue, and/ or cellular level of organization. In 

situations where it is not possible to determine the threshold for an observed effect, the action 

area is not spatially limited and is assumed to be the entire United States.

7.7 Drinking Water Assessment

Drinking water assessments have been conducted to support human health risk assessments of 

the cypermethrins, based on all the available environmental fate information. Any further 

drinking water assessments will incorporate model estimates of the cypermethrins in surface and 

ground waters. Concentrations in surface waters will be estimated using FQPA Index Reservoir 

Screening Tool (FIRST, v.1.1.1, 12/18/07) (or subsequently using PRZM/ EXAMS, with the 

Index Reservoir if refinements are required). Ground water estimates of concentrations will be 

obtained using the Screening Concentration In GRound Water (SCI-GROW) model (v.2.3, July 

2003). Further drinking water assessments will also include a summary of available surface and 

ground water monitoring data. 

7.8 Endocrine Disruptor Screening Program

As required by FIFRA and the Federal Food, Drug, and Cosmetic Act (FFDCA), EPA reviews 

numerous studies to assess potential adverse outcomes from exposure to chemicals. 

Collectively, these studies include acute, subchronic and chronic toxicity, including assessments 

of carcinogenicity, neurotoxicity, developmental, reproductive, and general or systemic toxicity. 

These studies include endpoints which may be susceptible to endocrine influence, including 

effects on endocrine target organ histopathology, organ weights, estrous cyclicity, sexual 

maturation, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For 

ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, 

developmental and reproductive effects in different taxonomic groups. As part of its 

reregistration decision, EPA reviewed these data and selected the most sensitive endpoints for 

relevant risk assessment scenarios from the existing hazard database. However, as required by 

FFDCA section 408(p), cypermethrin is subject to the endocrine screening part of the Endocrine 

Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 
61

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Accordingly, as 

part of registration review, EPA will issue future EDSP orders/data call-ins, requiring the 

submission of EDSP screening assays for cypermethrin. For further information on the status of 

the EDSP, the policies and procedures, the current and future chemical lists, the test guidelines 

and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/.

7.9 Preliminary Identification of Data Gaps

7.9.1 Environmental Fate Data Gaps

Given the large number of registered uses for the cypermethrins, the current database of one 

aerobic soil metabolism study and two terrestrial field dissipation studies is insufficient to 

describe the variability of environmental fate across the entire United States. Additional data are 

needed for guidelines 835.4100 (Aerobic Soil Metabolism) and 835.6100 (Terrestrial Field 

Dissipation). Also, because the greatest exposure route of concern is expected to be sediment, 

additional data are needed for aerobic and anaerobic aquatic metabolism (guidelines 835.4300 

and 835.4400, respectively) to describe the variability of the cypermethrins fate across the entire 

U.S.

Table 7.1 lists the status of the environmental fate data requirements for the cypermethrins.

Table 7.1. Summary of Environmental Fate Data Requirements for the Cypermethrins

Guideline 

# Data Requirement MRID #

Study 

Classification

Are Additional Data 

Needed for Risk 

Assessment?

835.2130 Hydrolysis 42620501 Acceptable no

835.2210 Photodegradation in 

Water 

42395701 Supplemental no

835.2410 Photodegradation on Soil 42129001 Supplemental no

835.2370 Photodegradation in Air No Data Waived no

835.4100 Aerobic Soil Metabolism 42156601 Acceptable Yes

835.4200 Anaerobic Soil 

Metabolism

42156602 Acceptable no

835.4400 Anaerobic Aquatic 

Metabolism

44876105 Acceptable Yes
62

Table 7.1. Summary of Environmental Fate Data Requirements for the Cypermethrins

Guideline 

# Data Requirement MRID #

Study 

Classification

Are Additional Data 

Needed for Risk 

Assessment?

835.4300 Aerobic Aquatic 

Metabolism

45920801 Acceptable Yes

835.1230 LeachingAdsorption/Desorption42129003, 

42124002

Acceptable no

835.1410 Laboratory Volatility No Data Waived no

835.8100 Field Volatility No Data Waived no

835.6100 Terrestrial Field 

Dissipation

42459601 Acceptable Yes

835.6200 Aquatic Field Dissipation 44876107 Supplemental no aquatic uses

835.6300 Forestry Dissipation No Data N/A no

NonGuideline

NonGuideline

Washoff Study

Study of fate in PubliclyOwned Treatment Works 

(POTW)

48072902

No Data

In Review

N/A

No

Yes

7.9.2 Effects

For registration review, the following studies are requested to resolve uncertanties in the risk 

assessment:

Guideline Number: 850.2100

Study Title: Avian acute oral toxicity test (passerine species) with TGAI

Acute avian oral toxicity data are needed for either one waterfowl or one upland game species 

and one passerine species under the Part 158 data requirements (CFR 40 2008) for conventional 

pesticides. Because passerine species have higher metabolic rates due to their smaller sizes than 

either waterfowl or upland game bird species, and because they may utilize different metabolic 

pathways, they may be more or less sensitive to cypermethrin. A recent study reported that at 

least one passerine species (canary, Serinus sp) is sensitive to a formulated pyrethroid, beta

cyfluthrin, with a calculated LD50 of 170 mg/kg bw (Addy-Orduna et al 2011). The other two 

species tested in this study, shiny cowbird (Order Passeriformes) and eared doves (Order 

Columbiformes), showed decreased sensitivity to beta cyfluthrin (LD50 of 2234 mg/kg bw and 

2271 mg/kg bw, respectively). Based on a preliminary screen using the highest agricultural 

application scenario for cypermethrin (see Table 3.3), the highest peak dose-based EEC is 96 
63

mg/kg bw. This level of acute exposure could be environmentally-relevant if cypermethrin 

shows the same increase in toxicity to passerine species that is indicated by the study with beta 

cyfluthrin. An additional line of evidence from reported bird incidents (I000103-010 and 

I011348-001, Appendix B), shows that most of the birds affected were passerines (although the 

causes were uncertain). In order to properly characterize risk to passerines, an avian oral toxicity 

test is requested. A passerine study protocol should be submitted for review by the Agency prior 

to initiation of the study.

Guideline Number: 850.2300

Study Title: Avian reproduction test with TGAI 

Though reproduction data is available for the cypermethrins, the maximum treatment level tested 

(50 ppm) in the acceptable studies was below expected exposure in cotton (66 ppm on short 

grass). There were no treatment related effects observed at 50 ppm. 

Non-Guideline16,17

Study Title: Acute Freshwater Invertebrate Toxicity (Hyalella azteca) with TEP

Acute water column tests with Hyallela azteca have been requested in pyrethroid problem 

formulations based on the increased sensitivity of this species to pyrethroid insecticides. The

850.1020 test guideline for Gammarid amphipods is recommended with appropriate 

modifications to address specific testing needs of H. azteca. The registrant should submit a 

protocol prior to test initiation or submit any open literature studies that may fulfill this data gap. 

The TEP should correspond to those formulated products that are labeled for outdoor uses with 

the greatest potential for aquatic exposures and contain the highest synergist:a.i. ratio.

Guideline Number: OCSPP 850.1760 (in prep), OCSPP 850.1770 (in prep.) and OCSPP 

850.1780 (in prep.) with TGAI

Study Title: Whole sediment: chronic invertebrates freshwater and marine

No chronic sediment toxicity tests for freshwater or marine invertebrates have been submitted for 

the cypermethrins to satisfy the Agency’s updated data requirements for outdoor uses in 40 CFR 

Part 158 (October 26, 2007). For cypermethrin, available information indicates that benthic 

organisms may be exposed via run-off or spray drift applications used in agricultural, forest, and 

residential settings. Based on calculations in the most recent EFED assessment, the 21-day

sediment porewater EECs predicted for cypermethrin ranged from 0.0036 to 0.0253 μg a.i./L 

(USEPA 2006b). The upper end of this range exceeds 0.1 of the most sensitive acute LC/EC50

(0.0036 μg a.i./L for amphidpod), which satisfies one of the criteria for requiring chronic whole 

sediment toxicity testing under 40 CFR Part 158. Furthermore, chronic reproductive effects were 

seen in water column studies with aquatic invertebrates (mysid shrimp), with a NOAEC = 

0.000781 μg a.i./L and LOAEC = 0.00197 μg a.i./L.

The cypermethrins are expected to persist in sediments, based on half-lives in submitted soil 

 16 The DCI will indicate that TEP studies on freshwater invertebrates and freshwater fish are required on 

coformulated products containing the highest ratio of the synergist piperonyl butoxide (PBO) to permethrin and the 

highest ratio of the synergist MGK-264 to permethrin. 17 The DCI will require that a study protocol be submitted for review and approval by the Agency prior to this study 

being initiated.
64

metabolism and aquatic metabolism studies (aerobic soil ~60 days; aerobic aquatic metabolism, 

10 days) (MRIDs 42156601 and 45920801). These half-life values exceed the 40 CFR Part 158 

criterion of 10 days.

The third set of trigger criteria for needing chronic testing (Kd > 50 or log KOW >3 or KOC > 

1000) is also met for the cypermethrins (log KOW is 6.4, and the mean KOC value is ~141,700.

The physicochemical property triggers (Kd, KOW and KOC) reflect the propensity of the chemical 

to partition onto the particulate or organic matter phases of sediments. Exceeding any one of the 

physicochemical property triggers listed above is sufficient for indicating the pesticide has 

reasonable potential for partitioning to the sediment compartment. 

Chronic whole sediment tests on Hyalella azteca, Chironomus tentans, and Leptocheirus 

plumulosus are requested. Although both are freshwater species, Hyalella and Chironomus differ 

substantially in their morphology ( crustacean vs. insect), ecological niche (epibenthic v. infaunal 

species), and physiology. Evidence also suggests that Hyalella is among the more sensitive 

invertebrates to pyrethroids based on water column tests (Maund et al., 2002; Weston and 

Jackson, 2009). The cypermethrins have the potential to enter estuarine/marine water bodies 

based on current usage patterns that include coastal areas. Therefore, testing is also needed for 

an estuarine/marine sediment-dwelling invertebrate species. 

Until the final OCSPP guidelines for chronic sediment toxicity tests are published, the registrant 

should submit a protocol to EFED for approval prior to test initiation, considering the following 

methods:

• Test Method 100.4: Hyalella azteca 42-d Test for Measuring the Effects of Sediment 

Associated Contaminants on Survival, Growth, and Reproduction in USEPA 2000 

Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated 

Contaminants with Freshwater Invertebrates EPA 600/R-99/064 (OCSPP 850.1770, in 

prep.);

• Test Method 100.5: Life-cycle Test for Measuring the Effects of Sediment-associated 

Contaminants on Chironomus dilutus (formerly known as C. tentans) in USEPA 2000 

Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated 

Contaminants with Freshwater Invertebrates EPA 600/R-99/064 (OCSPP 850.1760, in 

prep.); and 

• Leptocheirus plumulosus in USEPA 2001 Method for Assessing the Chronic Toxicity of 

Marine and Estuarine Sediment-associated Contaminants with the Amphipod 

Leptocheirus plumulosus EPA 600/R-01/020 (OCSPP 850.1780, in prep.).

Non-Guideline 18,19

Study Title: Fish Acute Toxicity Test (freshwater) with TEP.

No acceptable acute studies for the cypermethrins TEP with synergists (PBO or MGK) have 

 18The DCI will indicate that TEP studies on freshwater invertebrates and freshwater fish are required on 

coformulated products containing the highest ratio of the synergist piperonyl butoxide (PBO) to permethrin and the 

highest ratio of the synergist MGK-264 to permethrin.

19 The DCI will require that a study protocol be submitted for review and approval by the Agency prior to this study 

being initiated.
65

been submitted for fish. Since the cypermethrins can reach aquatic habitats via run-off or spray 

drift applications used in agricultural, forest, and residential settings and can be directly applied 

to water via application to cattle livestock, EPA needs data on the formulated products 

containing synergists. Without toxicity data on the range of TEPs produced, the Agency would 

have to presume acute toxicity to listed and non-listed fish and aquatic-phase amphibians, but 

would not be able to quantify the risk. The TEP should correspond to those formulated products 

that are labeled for outdoor uses with the greatest potential for aquatic exposures and contain the 

highest synergist:a.i. ratio.

Guideline Numbers: 850.4150 and 850.4250

Study Title: Vegetative vigor and Seedling emergence, TierII20

No acceptable toxicity data are currently available to assess the risk of the cypermethrins to nontarget terrestrial plants. Since the cypermethrins have many outdoor uses, vegetative vigor and 

seedling emergence studies are needed. In addition, four minor terrestrial plant incidents have 

been reported to the Agency involving cypermethrin. Phytotoxicity data are needed to assess the 

impact of the cypermethrins on non-target terrestrial plants. 

with TEP

Guideline Number: 850.4400 and 850.5400

Study Title: Aquatic Plant Growth (algal and aquatic vascular plant toxicity) TierII21

No acceptable toxicity data are currently available to assess the risk of the cypermethrins to nontarget aquatic nonvascular and vascular plants. Since the cypermethrins have many outdoor uses, 

aquatic plant growth toxicity studies are requested with either technical or a typical end-use 

product.

with 

TEP or TGAI

The Agency is aware that additional data on the cypermethrins are available for the European 

Food Safety Authority reports (EFSA, 2006). It is recommended that any applicable data 

generated for the European review process be submitted to EPA.

Table 7.2 lists the status of the ecological effects data requirements for cypermethrin.

Table 7.2. Ecological Effects Data Requirements for the Cypermethrins.

Data Requirement

Does EPA Have

Data To Satisfy

This 

Requirement?

Bibliographic

Citation (MRID)

Must Additional

Data Be Submitted

Under FIFRA 3(c)(2)(B)?

§158.630 TERRESTRIAL ORGANISM TESTING

850.2100 Acute Avian Oral, 

Quail/Duck/Passerine

Partially 44546024 Yes

 20 A Tier II study is required. The DCI will provide that a Tier I plant study may be conducted in lieu of a Tier II 

study with the understanding that any adverse effects observed by the Tier I study would necessitate conduct and 

submission of a Tier II study as well.

1

21 A Tier II study is required. The DCI will provide that a Tier I plant study may be conducted in lieu of a Tier II

study with the understanding that any adverse effects observed by the Tier I study would necessitate conduct and 

submission of a Tier II study as well.
66

Table 7.2. Ecological Effects Data Requirements for the Cypermethrins.

Data Requirement

Does EPA Have

Data To Satisfy

This 

Requirement?

Bibliographic

Citation (MRID)

Must Additional

Data Be Submitted

Under FIFRA 3(c)(2)(B)?

850.2200 Acute Avian Diet, Quail Yes 00090072 No

850.2200 Acute Avian Diet, Duck Yes 00090071 No

850.2300 Avian Reproduction Quail Yes 00090074 No

850.2300 Avian Reproduction Duck Yes 00090073 No

§158.630 AQUATIC ORGANISM TESTING

850.1075 Acute Fish Toxicity Bluegill Yes 44546029 No

850.1075 Acute Fish Toxicity Rainbow 

Trout 

Yes 44546027 No

Non-Guideline Acute Fish Toxicity 

(TEP)

No 2

00088947 Yes

850.1010 Acute Aquatic Invertebrate 

3,4

Yes 44423501 No

Non-Guideline Acute Aquatic 

Invertebrate (TEP) 2

No

 

00062793/92027014 Yes

850.1075 Acute Est/Mar Toxicity Fish 

3,4

Yes 00090075, 41968211, 

44546033

No

850.1075 Acute Est/Mar Toxicity Fish 

(TEP)

No N/A No

850.1035 Acute Est/Mar Toxicity Shrimp Yes 4070532, 4244601, 

00089043, 44561209

No

850.1035 Acute Est/Mar Toxicity Shrimp 

(TEP) 

No N/A No

850.1025 Acute Est/Mar Toxicity Mollusk Yes 89049 No

850.1025 Acute Est/Mar Toxicity Mollusk 

(TEP) 

No N/A No

850.1400 Early Life Stage Fish Yes 89039 No

7.10 850.1300 Life Cycle Aquatic 

Invertebrate (freshwater) 

No N/A Yes

7.11 850.1350 Life Cycle Aquatic 

Invertebrate (saltwater)

5

Yes 42725301 No

850.1500 Life Cycle Freshwater Fish No N/A No

850.1730 Bioaccumulation in Fish

6

Yes 42868203 No
67

Table 7.2. Ecological Effects Data Requirements for the Cypermethrins.

Data Requirement

Does EPA Have

Data To Satisfy

This 

Requirement?

Bibliographic

Citation (MRID)

Must Additional

Data Be Submitted

Under FIFRA 3(c)(2)(B)?

OCSPP 850.1760 (in prep.), 850.1770 (in 

prep.) and 850.1780 (in prep.) Whole 

sediment: chronic invertebrates 

freshwater & marine

No N/A Yes7

7.12 850.1020 Aquatic Invertebrate Acute 

Toxicity (Hyalella)

Yes 44074406 No

§158.660 PLANT PROTECTION TESTING

850.4100 Seed Germ, Seedling Emergence No NA Yes

850.4150 Vegetative Vigor

8

No NA Yes

850.4400, 850.5400 Aquatic Plant Growth

9

No NA Yes10

§158.490 INSECT POLLINATOR TESTING

850.3020 Honey Bee Acute Contact Yes 260647 No

850.3030 Honey Bee Residue on Foliage No N/A No

850.3040 Field Test for Pollinators No N/A No

N/A = Not applicable because no citation is available.

1 Data are needed for a passerine species. The registrant should submit a protocol prior to conducting this study.

2

TEP should correspond to those formulated products that are labeled for outdoor uses with the greatest potential for aquatic 

exposure, and containing the highest synertist:a.i. ratio. Invertebrate test should be with Hyalella.

3 

products containing the highest ratio of the synergist piperonyl butoxide (PBO) to permethrin and the

The DCI will indicate that TEP studies on freshwater invertebrates and freshwater fish are required on coformulated

highest ratio of the synergist MGK-264 to permethrin.

4

being initiated.

The DCI will require that a study protocol be submitted for review and approval by the Agency prior to this study

5 Study needed for chronic freshwater invertebrate. 

6 No additional data is needed at this time. The results from the fish early-life stage studies will be used in the upcoming risk 

assessment to evaluate the chronic risk of cypermethrin to fish species. 7 Until the final OCSPP guidelines for chronic sediment toxicity tests are published, the registrant should submit a protocol 

to EFED for approval prior to test initiation.

8 Tier II tests needed if a tested terrestrial species exhibits a statistically significant detrimental effect in the Tier I study.

9

Tier II tests needed if a tested aquatic species exhibits a statistically significant detrimental effect in a Tier I study.

10 Studies required for aquatic nonvascular and vascular plants. Test may be conducted with technical grade cypermethrin or 

a typical end-use product.
68

8 References

Addy-Orduna, L.M., Zaccagnini, M-E, Canavelli, S.B. and P. Mineau. 2011. Formulated betacyfluthrin shows wide divergence in toxicity among bird species. Journal of Toxicology. Volume 

2011, Article ID 803451: 10 pages.

Di Toro, DM, CS Zarba, DJ Hansen, WJ Berry, RC Swartz, CE Cowan, SP Pavlou, HE Allen, 

NA Thomas and PR Paquin. 1991. Technical basis for establishing sediment quality criteria for 

nonionic organic chemicals using equilibrium partitioning. Environ. Toxicol. Chem. 10:1541-

1583.

European Food Safety Authority, 2006. Draft assessment report for the active substance zetacypermethrin. Council Directive 91/414/EEC. Volume 3, Annex B, Part B.9.

Food and Agriculture Organization of the United Nations. FAO PESTICIDE DISPOSAL 

SERIES 8. Assessing Soil Contamination: A Reference Manual. Appendix 2. Parameters of 

pesticides that influence processes in the soil. Editorial Group, FAO Information Division: 

Rome, 2000. http://www.fao.org/DOCREP/003/X2570E/X2570E00.htm (accessed 12/06/11)

Matsumura, F. 1985. Toxicology of insects. 2nd ed. Plenum New York.

Stewart, D. 1998. The Evaluation of Synergistic Action in the Laboratory and Field. p. 173-198 

In: Piperonyl Butoxide: the Insecticide Synergist. Academic Press.

Tomlin CDS; The Pesticide Manual. 11th Ed. Crop Protection Publ: British Crop Protection 

Council 49 Downing St, Farnham United Kingdom (1997).

USEPA. 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of 

Research and Development, Washington, D.C. EPA/630/R-95/002F. April 1998. 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759

USEPA. 2001. Method for Assessing the Chronic Toxicity of Marine and Estuarine Sedimentassociated Contaminants with the Amphipod Leptocheirus plumulosus EPA 600/R-01/020 

(OCSPP 850.1780, in prep.).

USEPA. 2002. Technical Basis for the derivation of Equilibrium Partitioning Sediment 

Guidelines (ESGs) for the Protection of Benthic Organisms: Nonionic Organics [Draft]. EPA 

Document No. 822R02041. October 2002.

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs. United States Environmental Protection Agency (USEPA). Environmental Fate and 

Effects Division. Office of Pesticide Programs. Available at 

http://www.epa.gov/espp/consultation/ecorisk-overview.pdf (accessed 05/17/2011).

USEPA. 2006a. Reregistration Eligibility Decision (RED) Document for N-Octyl bicycloheptene 
69

dicarboximide (MGK-264), List B, Case No. 2430, Office of Chemical Safety and Pollution 

Prevention, Document ID EPA 738-R-06-006, June 2006.

USEPA. 2006b. Reregistration Eligibility Decision (RED) Document for Cypermethrin, List B, 

Case No. 2130, Office of Chemical Safety and Pollution Prevention, Document ID EPA OPP2005-0293, June 2006, revised January 2008.

USEPA. 2008. OPPTS 835.6100 Terrestrial Field Dissipation. EPA 712-C-08-020. October 

2008. Office of Chemical Safety and Pollution Prevention (formerly Office of Prevention, 

Pesticides, and Toxic Substances). United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (accessed 

05/17/2011).

USEPA. 2011. BEAD Chemical Profile for Registration Review: Cypermethrin (109702) and 

Zeta-Cypermethrin (129064). Memorandum from Biological and Economic Analysis Division 

to Pesticide Reevaluation Division.
70

9 Fate and Ecotoxicity Bibliography

Cypermethrin Fate Bibliography

161-1 Hydrolysis

MRID Citation Reference

62795 2051028 Leahey, J.P.; Richardson, K.; Woods, T.M.; et al. (1980) Hydrolysis of 

Cypermethrin. (Unpublished study received Dec 5, 1980 under 279-EX-86; 

prepared by Imperial Chemical Industries, Ltd., England, submitted by FMC 

Corp., Philadelphia, Pa.; CDL: 243861-AI) 

65821 2016262= 

summary

See 62795 

above

Leahey, J.P.; Richardson, K.; Woods, T.M.; et al. (1980) Hydrolysis of 

Cypermethrin: Report Series RJ0117B. (Unpublished study received Dec 29, 

1980 under 10182-EX-19; prepared by Imperial Chemical Industries, Ltd., 

England, submitted by ICI Americas, Inc., Wilmington, Del.; CDL:244018-D) 

89991 2051041

2016262= 

summary 

Rapley, J.H.; Arnold, D.J.; Vincent, J. (1981) Cypermethrin: Degra- dation in 

River and Pond Waters and Sediments: Report Series RJ 0175B; 5G 1/5. 

(Unpublished study received Dec 30, 1981 under 10182-64; prepared by 

Imperial Chemical Industries, Ltd., Eng- land, submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL: 070559-B) 

163083 Open lit Takahashi, N.; Mikami, N.; Matsuda, T.; et al. (1985) Hydrolysis of the 

pyrethroid insecticide Cypermethrin in aqueous media. J. Pesticide Sci. 

10(4):643-648. 

41662701 2016265

2016262= 

summary

Allsup, T. (1976) Hydrolysis of FMC 45497, FMC 45724, and FMC 30980 

Insecticides: Lab Project Number: W/0131. Unpublished study prepared by 

FMC Corp. 54 p. 

42620501 2016133 Clifton, J. (1992) Environmental Fate Studies: Hydrolysis Studies of 

Cypermethrin in Aqueous Buffered Solutions: Lab Project Number: 

191E1192E1: P-2771. Unpublished study prepared by FMC Corp. 77 p. 

161-2 Photodegradation-water

MRID Citation Reference

42141501 See 42395701-

revised

Estigoy, L.; Ruzo, L.; Shepler, K. (1991) Photodegradation of ?carbon 14-acid| 

and ?carbon 14-alcohol|Cypermethrin in Buffered Aqueous Solution at pH7 by 

Natural Sunlight: Lab Project Number: 247/248W: 247/248W-1: 191E1290E1. 

Unpublished study prepared by Pharmacology and Tox. Research Lab. (PTRLWest). 121 p. 

42395701 2016134 Estigoy, L.; Ruzo, L.; Shepler, K. (1992) Photodegradation of ?carbon 14-acid| 

and ?carbon 14-alcohol| Cypermethrin in Buffered Aqueous Solution at pH 7 

by Natural Sunlight: Revised: Lab Project Number: 247/248W: 247/248W-1: 

191E1290E1. Unpub- lished study prepared by Pharmacology and Toxicology 

Research Research Lab (PTRL-West) and FMC Corp. 144 p. 

89992 2016265 

summary pg 7

Day, S.R.; Leahey, J.P. (1980) ^14IC-Cypermethrin: Aqueous Photodegradation in Sunlight: Report Series RJ 0154B; SG 1/3. (Un- published study 

received Dec 30, 1981 under 10182-64; prepared by Imperial Chemical 
71

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070559-C) 

161-3 Photodegradation-soil

MRID Citation Reference

89993 2016265 

summary pg 

11

Hall, J.S.; Leahey, J.P.; Curl, E.A. (1981) Cypermethrin: Photodeg- radation on 

a Soil Surface: Report Series RJ 0192B; 5B 1/15. (Unpublished study received 

Dec 30, 1981 under 10182-64; pre- pared by Imperial Chemical Industries, 

Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070559-D) 

126103 Open lit –

cited in 

2016265

Roberts, T.; Standen, M. (1981) Further studies of the degradation of the 

pyrethroid insecticide cypermethrin in Soils. Pestic. Sci. 12:285-296. (Also In 

unpublished submission received Feb 8, 1983 under 20954-115; submitted by 

Zoecon Corp., Palo Alto, CA; CDL:249513-C) 

42129001 2016135 Estigoy, L.; Ruzo, L.; Shepler, K. (1991) Photodegradation of Car- bon 14-

Acid and Carbon 14-Alcohol Cypermethrin in/on Soil by Natural Sunlight: Lab 

Project Number: 249/250W: 191E1390E1: PC- 0159. Unpublished study 

prepared by PTRL West. 115 p. 

162-1 Aerobic soil metabolism

MRID Citation Reference

42156601 2016136 Ramsey, A. (1991) Environmental Fate Studies: Aerobic Soil Metabolism of 

Cypermethrin in a Sandy Loam Soil: Lab Project Number: 191E2190E1. 

Unpublished study prepared by FMC Corp. 99 p. 

62796 Open lit 

2016262= 

summary

Roberts, T.R.; Standen, M.E. (1977) Degradation of the pyrethroid 

Cypermethrin NRDC 149 ... isomers in soils. Pesticide Science 8:305-319. 

(Also In unpublished submission received Dec 5, 1980 under 279-EX-86; 

submitted by FMC Corp., Philadelphia, Pa.; CDL: 243861-AJ) 

89995 2051031 Harvey, B.R.; Zinner, C.K.J.; White, R.D.; et al. (1981) Cypermeth- rin: 

Degradation in Soil in the Laboratory: Report Series RJ 01262B. (Unpublished 

study received Dec 30, 1981 under 10182- 64; prepared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070559-F) 

65823 2016262= 

summary pg 

17

Standen, M.E.; Dutton, A.J.; Roberts, T.R. (1976) The Degradation of the 

Insecticide WL 43467 in Soil under Laboratory Conditions: Group Research 

Report WKGR.0094.76. (Unpublished study received Dec 29, 1980 under 

10182-EX-19; prepared by Shell Research, Ltd., England, submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:244018-F) 

65824 2016262= 

summary pg 

20

Standen, M.E.; Roberts, T.R. (1980) Further Studies of the Degradation of the 

Insecticide WL 43467 (Cypermethrin) in Soil under Laboratory Conditions: 

Group Research Report BLGR.0034.78. (Unpublished study received Dec 29, 

1980 under 10182-EX-19; prepared by Shell Research, Ltd., submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:244018-G) 

65825 2016262= 

summary pg 

Swaine, H.; Hayward, G.J. (1979) Cypermethrin: Laboratory Degradation on 

Two Standard Soils. Part I.: Report Series RJ0115B. (Unpublished study 
72

24 received Dec 29, 1980 under 10182-EX-19; prepared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:244018-I) 

89997 Part 2 Swaine, H.; Hayward, G.J. (1981) Cypermethrin: Laboratory Degrada- tion on 

Two Standard Soils: Part II: Report Series RJ 0178B. (Unpublished study 

received Dec 30, 1981 under 10182-64; pre- pared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070559-H) 

162-2 Anaerobic soil metabolism

MRID Citation Reference

42156602 2016137 Ramsey, A. (1991) Environmental Fate Studies: Anaerobic Soil Metabolism of 

Cypermethrin in a Sandy Loam Soil: Lab Project Number: 191E2590E1. 

Unpublished study prepared by FMC Corp. 93 p. 

162-3 Aerobic Aquatic Metabolism

65819 2051041

2016262= 

summary

Rapley, J.H.; Arnold, D.J.; Vincent, J.; et al. (1980) Cypermethrin: Degradation 

in River Water and Sediments: Report Series RJ 0119 B. (Unpublished study 

received Dec 29, 1980 under 10182-EX-19; prepared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL: 244018-B) 

45920801

163-1 Leach/adsorp/desorption

MRID Citation Reference

58861 2016265 

summary pg 

32

Kaufman, D.D.; Russell, B.A.; Helling, C.S.; et al. (1978) Movement of 

Decamethrin, Cypermethrin, Permethrin and Their Degradation Products in 

Soil. (Unpublished study received Nov 13, 1980 under 8340-EX-6; prepared by 

U.S. Dept. of Agriculture, Agri- cultural Environmental Quality Institute, 

Pesticide Degradation Laboratory and Univ. of Maryland, Botany Dept., 

submitted by American Hoechst Corp., Somerville, N.J.; CDL:099744-H) 

65826 2016265= 

summary pg 

31

Prashad, S.; Newby, S.E. (1976?) PP 383: Leaching on Thick-layer Soil 

Chromatograms: Report Series TMJ 1525 B. (Unpublished study received Dec 

29, 1980 under 10182-EX-19; prepared by Imperial Chemical Industries, Ltd., 

England, submitted by ICI Americas, Inc., Wilmington, Del.; CDL:244018-N) 

no MRID on 

summary

2016265= 

summary

Prashad, S.; Newby, S.E. (1977)mobility of permethrin and its degradation 

products in soil

65827 2016265= 

summary pg 

33

Stevens, J.E.; Riley, D. (1971?) Pesticide Mobility in Soil: Determination by 

Soil Thick-layer Chromatography: Report Series TMJ 1080A. (Unpublished 

study received Dec 29, 1980 under 10182-EX- 19; prepared by ICI Plant 

Protection, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:244018-O) 

No MRID 2016265 

summary pg Clarke, C.E. 1977. Adsorption of PP557 and It’s Hydrolysis products
73

46

90004 2051032

2016265 

summary pg 

35

Stevens, J.E.B.; Hill, I.B. (1980) Cypermethrin: Mobility of Cypermethrin and 

Its Degradation Products in Soil Columns: Report Series RJ 0166B; 5B 1/9. 

(Unpublished study received Dec 30, 1981 under 10182-64; prepared by 

Imperial Chemical Industries, Ltd., England, submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070559-T) 

90053 2016265 

summary pg 

43

Stevens, J.E.B.; Poole, N.J. (1981) Cypermethrin: Adsorption and Desorption 

in Soil: Report Series RJ0184B; 5B 1/14. (Unpub- lished study received Dec 

30, 1981 under 10182-64; prepared by Imperial Chemical Industries, Ltd., 

England, submitted by ICI Americas, Inc., Wilmington, Del.; CDL:070560-B) 

99038 Open lit

Summary in 

2016265 pg 32

Kaufman, D.D.; Russell, B.A.; Helling, C.S.; et al. (1981) Movement of 

cypermethrin, decamethrin, permethrin, and their degradation products in soil. 

Journal of Agricultural and Food Chemistry 29 (2):239-245. 

(Also~In~unpublished submission received Dec 30, 1981 under 10182-64; 

submitted by ICI Americas, Inc., Wilming- ton, Del.; CDL:070559-S) 

152747 DER not 

located

Weissler, M.; Hill, I. (1980) Cypermethrin: Leaching of Formulated 

Cypermethrin in Soil Columns: Report No. RJ0137B. Unpublished study 

prepared by Imperial Chemical Industries PLC. 16 p. 

41403102 DER not 

located

Hebert, V. (1990) Sorption Characteristics of Cypermethrin on Soils, Plastics, 

and Glass: Lab Project Number: 191E5589E1. Un- published study prepared by 

FMC Corp. 27 p. 

42129002 2016138 Curry, S. (1991) Leaching of Carbon 14-Cypermethrin in Soil Follow- ing 

Aerobic Aging: Lab Project Number: 191E3190E1. Unpublished study 

prepared by FMC Corp. 97 p. 

42129003 2016427 Froelich, L. (1991) Soil Mobility Studies: Adsorption/Desorption Studies of 

Cypermethrin: Lab Project Number: 191E3290E1. Unpub- lished study 

prepared by FMC Corp. 65 p. 

44074404 DER not 

located

Goggin, U.; Gentle, W.; Hamer, M.; et al. (1996) Cypermethrin: Adsorption 

and Desorption Properties in Sediment: Lab Project Number: RC0004: 

95JH167. Unpublished study prepared by Zeneca Agrochemicals. 32 p. 

164-1 Terrestrial field dissipation

MRID Citation Reference

65828 2016262= 

summary pg 

33

Ussary, J.P.; Pearson, F. (1980) Cypermethrin Dissipation in Soils: Report 

Series TMU0511/B. (Unpublished study received Dec 29, 1980 under 10182-

EX-19; submitted by ICI Americas, Inc., Wilmington, Del.; CDL:244018-P) 

115283 2016130-

summary

Tilka, M.; Stearns, J.; Fullmer, O. (1982) Dissipation of Cyper- methrin 

Residues in Soil: RAN-0046. (Unpublished study received Oct 1, 1982 under 

279-3026; prepared in cooperation with Analyt- ical Bio-Chemistry 

Laboratories, Inc., submitted by FMC Corp., Philadelphia, PA; CDL:248522-

C) 

141761 2016130-

summary

Kinnee, G. (1984) Dissipation of Dichlorovinyl Acid and m-Phenoxy- benzoic 

Acid Residues in Soil: RAN-0129. Unpublished study pre- pared by FMC 

Corp. 21 p. 

155291 2016131 Sterns, J. (1985) Dissipation of Cyperamide and m-Phenoxybenzalde- hyde 
74

Residues in Soil Treated with Ammo Insecticide: RAN-0149. Unpublished 

study prepared by FMC Corp. with review of previous- ly submitted soil 

studies appended. 39 p. 

NO MRID 2016131 Sterns, J.W. (1985) Dissipation of Cypermethrin, Dichlorovinyl Acid, and mPhenoxybenzoic Residues in Soil RAN-148. FMC Corporation, Agricultural 

Chemical Group, Philadelphia, PA.

42459601 2016139 Leppert, B. (1992) Ammo 2.5 EC Insecticide--Terrestrial Field Dissipation: 

Lab Project Number: 191E4191E1: RAN-0239. Unpublished study prepared by 

FMC Corporation. 182 p. 

136798 Overview FMC Corp. (1982) EPA Overview: Cypermethrin Soil Dissipation. (Unpublished study received Dec 20, 1983 under 279-3027; CDL: 072232-C) 

141760 FMC Corp. (1984?) Ammo Field Dissipation Studies. Unpublished study. 2 p. 

164-2 Aquatic Field Dissipation

142856 Protocol Wildlife International Ltd. (1985) PP321: An Evaluation of Runoff and Drift 

into an Aquatic Ecosystem: Protocol: Project No. 123- 135. Unpublished study. 

35 p. 

142857 Review not 

located 

Protocol

Kennedy, J. (1985) Biological and Physiological Survey of Perkin's Hill Farm 

Pond in the Year Prior to Application of a Pesticide for Aquatic Impact Studies: 

Project No. 123-133. Unpublished protocol prepared by Wildlife International 

Ltd. 192 p. 

150638 Preliminary site 

evaluation

Wildlife International Ltd. (1984) A Preliminary Evaluation of Three Potential 

Farm Pond Study Sites on the Eastern Shore of Maryland. Unpublished study. 

10 p. 

155795 Modeling –

SETAC 

presentation 

summary in 

2016262

Arnold, J.; Hill, I. (1984) The Fate of Cypermethrin in Water- sediment 

Models. Unpublished documents presented at the SETAC Fifth Annual 

Meeting; November, 1984, November, Washington, D.C. 2 p. 

156082 Site evaluations Hosmer, A.; Ekoniak, P.; Hill, I. (1986) An Evaluation of Farm Ponds in 

Midsouthern United States as Potential Exposure and Biological Effects Study 

Sites for Synthetic Pyrethroids. Un- published study prepared by Wildlife 

International Ltd. 118 p. 

65819 also 

under Aquatic 

Metabolism

2051041

2016262= 

summary

Rapley, J.H.; Arnold, D.J.; Vincent, J.; et al. (1980) Cypermethrin: Degradation 

in River Water and Sediments: Report Series RJ 0119 B. (Unpublished study 

received Dec 29, 1980 under 10182-EX-19; prepared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL: 244018-B) 

165-0 Accumulation Studies -- General

MRID Citation Reference

90055 2016265 

summary pg 

49

Ussary, J.P.; Fitzpatrick, R.D.; Claiborne, N.P. (1981) Cyper- methrin Residues 

in Samples from a 1980 Alabama Runoff Study: Report Series TMU0541/B. 

Rev. (Unpublished study received Dec 30, 1981 under 10182-64; submitted by 

ICI Americas, Inc., Wil- mington, Del.; CDL:070560-D) 
75

90056 2016265 

summary pg 

55

Cella, G.E. (1981) Monitoring the Fate of Cypermethrin after Aerial 

Applications on Cotton: UCCES Project No. 11507-92. (Unpub- lished study 

received Dec 30, 1981 under 10182-64; prepared by Union Carbide Corp., 

submitted by ICI Americas, Inc., Wilming- ton, Del.; CDL:070560-E) 

165-2 Field rotational crop

MRID Citation Reference

92027049 Registrant 

summary

Curry, K. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00098000. 

Cypermethrin Field Crop Rotation Study: Report No. TMU0738/B; Laboratory 

Study Identification No. RR 90-322B. Prepared by ICI Americas, Inc. 

Biological Research Center. 22 p. 

Not provided 2051036

2016265 

summary pg 

66-67

Woods, T.M. 1980. Cypermethrin Crop Rotation Study RJ 01618.

2016265 

summary pg 

67-76

Several Crop Rotation Studies with Cypermethrin and Permethrin

165-4 Bioaccumulation in fish

MRID Citation Reference

42868203 2016132 Giroir, E.; Stuerman, L. (1993) Cypermethrin (carbon 14) Bioconcentration by 

Bluegill Sunfish (Lepomis macrochirus): Lab Project Number: 191E5491E1: 

40018: PC-0189. Unpublished study prepared by ABC Labs, Inc. 311 p. 

92027050 Registrant 

summary

Hamer, M. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090061. 

The Accumulation and Elimination of WL 43467 by the Rainbow Trout (Salmo 

gairdneri): Report No.: TLGR. 0041. 78.: 16 p. 

92027051 Registrant 

summary

Hamer, M. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090062. 

The Accumulation, Distribution and Elimination of Ripcord by Rainbow Trout 

Using a Continuous-Flow procedure: Report No. SBGR. 81. 026.: 17 p. 

90061 2016265 

summary pg 

58

Baldwin, M.K.; Lad, D.D.; Selby, M.; et al. (1978) The Accumulation and 

Elimination of WL 43467 by the Rainbow Trout (Salmo gairdneri): Group 

Research Report TLGR.0041.78; 5C 4/12. (Unpublished study received Dec 

30, 1081 under 10182-64; prepared by Shell Research, Ltd., England, 

submitted by ICI Americas, Inc., Wilmington, Del.; CDL:070560-M) 

90063 2051037

2016265 

summary pg 

65

Hamer, M.J.; Hill, I.R. (1980) Cypermethrin: The Accumulation of 

Cypermethrin and Its Degradation Products by Channel Catfish in a Model 

Soil/Water System: Report Series RJ 0153B; 5C 4/8. (Un- published study 

received Dec 30, 1981 under 10182-64; prepared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070560-O) 

MRID not 

provided

2016265 

summary pg 

59

Bennett, D. 1981Acculmulation, Distribution and Elimination of Ripcord by 

Rainow trout
76

165-5 Bioaccum-aquatic non-target

MRID Citation Reference

44074403 DER not 

located- in 

review?

Rapley, J.; Hamer, M.; Goggin, U. (1996) Cypermethrin: Bioavailability to 

Daphnia magna in Sediment-Water Systems: Lab Project Number: RC0003: 

95JH153. Unpublished study prepared by Zeneca Agrochemicals. 25 p. 

44074405 DER not 

located- in 

review?

Gentle, W.; Goggin, U.; Rapley, J.; et al. (1996) Cypermethrin: Bioavailability 

to Chironomus tentans in Sediment-Water Systems: Lab Project Number: 

RC0005: 95JH205. Unpublished study prepared by Zeneca Agrochemicals. 24 

p. 

44074407 DER not 

located- brief 

summary in 

2050891 pg 19

Maund, S.; Hamer, M.; Kedwards, T. (1996) Partitioning, Bioavailability, and 

Toxicity of Cypermethrin in Aquatic Sediments: Overview of a Work Program 

of the Pyrethroid Working Group: Lab Project Number: RC0007. Unpublished 

study prepared by Zeneca Agrochemicals. 23 p. 

201-1 Droplet size spectrum

MRID Citation Reference

43766502 DER not 

located

Hewitt, A. (1995) Spray Drift Task Force: Atomization Droplet Size Spectra 

for Selective Active Ingredients: Lab Project Number: A92/004. Unpublished 

study prepared by SpraySearch- Daratech Pty. Ltd. and Spray Drift Task Force. 

175 p. 

Non Guideline Selections

49145 Open lit- DER 

not located

Wauchope, R.D. (1978) The pesticide content of surface water drain- ing from 

agricultural fields--a review. Journal of Environmen- tal Quality 7(4):459-472. 

(Also~In~unpublished submission re- ceived Nov 10, 1980 under 100-614; 

submitted by Ciba-Geigy Corp., Greensboro, N.C.; CDL:099692-K) 

62770 Not located FMC Corporation (19??) Qualitative Gas Chromatographic Analyses of 

NRDC-149 Technical. Undated method IV-A. (Unpublished study received 

Dec 5, 1980 under 279-EX-86; CDL:243861-I) 

62771 Not located FMC Corporation (1980) High Pressure Liquid Chromatography (HPLC) 

Method of Analysis for Cypermentrin (sic) (NRDC-149) by Internal Standard 

Used for Technical and Formulated Goods (Total Isomer Assay Only). Method 

IX dated Sep 15, 1980. (Unpublished study received Dec 5, 1980 under 279-

EX-86; CDL:243861-J) 

65829 2016262= 

summary pg 34

Fitzpatrick, R.D. (1980) A Gas-liquid Chromatographic Method for the 

Determination of Cypermethrin (PP383) in Soils: Report Series GRAM-7. 

Method dated Sep 1980. (Unpublished study received Dec 29, 1980 under 

10182-EX-19; submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:244018-Q) 

89998 Open lit 

Summary in 

Chapman, R.A.; Tu, C.M.; Harris, C.R.; et al. (1981) Peristence of five 

pyrethroid insecticides in sterile and natural, mineral and organic soil. Bulletin 
77

2016265 pg 22 of Environmental Contamination and Toxi- cology 26:513-519. (Also in 

unpublished submission received Dec 30, 1981 under 10182-64; submitted by 

ICI Americas, Inc., Wil- mington, Del.; CDL:070559-I) 

89999 2016265 

summary pg 26

Johnen, B.G.; Drew, E.A.; Davies, P.I. (1977) Evaluation of the Effects of 

Agrochemicals on Soil Microorganisms and Their Activ- ities--Methods 

Currently in Use at Jealott's Hill Research Sta- tion: AR 2660A; 5B 4/3. 

(Unpublished study received Dec 30, 1981 under 10182-64; prepared by 

Imperial Chemical Industries, Ltd., England, submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070559-L) 

No MRID on 

Summary

2016265 

summary pg 26

Johnen, B.G.; Drew, E.A.; Davies, P.I. (1977) PP557 Effects of on Soil 

Microbial Populations and Enzymic Activities

90002 2016265 

summary pg 30

Street, J.R.; Hill, R.W.; Harland, B.J. (1981) Assessment of the Effect of 

Cypermethrin on the Activated Sludge Sewage Treatment Process Using a 

Semi-continuous Laboratory System: BL/B/2062; 5C 3/2. (Unpublished study 

received Dec 30, 1981 under 10182-64; prepared by Imperial Chemical 

Industries, Ltd., England, submit- ted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070559-Q) 

90003 2016265 

summary pg 31

Leahey, J.P.; Stapleton, A.P.; Milner, S.D.; et al. (1981) Cyper- methrin: 

Degradation by Activated Sludge: Report Series RJ 0179B; 5C.1/4. 

(Unpublished study received Dec 30, 1981 under 10182-64; prepared by 

Imperial Chemical Industries Ltd., sub- mitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070559-R) 

97456 Open lit DER 

not located

Tu, C.M. (1980) Influence of five pyrethroid insecticides on mi- crobial 

populations and activities in soil. Microbial Ecology 5:321-327. 

(Also~In~unpublished submission received Mar 17, 1982 under 59-200; 

submitted by Burroughs Wellcome Co., Research Triangle Park, N.C.; 

CDL:247048-D) 

99037 2016265 

summary pg 25

Castle, D.L.; Drew, E.A.; Slinger, J.M.; et al. (1980) Cypermeth- rin: Effects on 

Soil Microbial Processes: Report Series RJ 0165B; 5B 4/7. (Umpublished study 

received Dec 30, 1981 under 10182-64; prepared by Imperial Chemical 

Industries, Ltd., Eng- land, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL: 070559-K) 

46535601 Registrant 

assessment

Cheplick, J. (2005) National Runoff, Erosion, and Leaching Assessment with 

the Pesticide Root Zone Model (PRZM): Pyrethroid. Project Number: 

WEI/794/05. Unpublished study prepared by Waterborne Environmental, Inc. 

(WEI). 14 p.

46535602 Registrant 

assessment

Cheplick, J. (2005) Direct Observation Based Method to Assign Topographic 

Factor (LS) to Areas of Concern with Quantified Statistical Confidence: 

(Pyrethroid). Project Number: WEI/794/05. Unpublished study prepared by 

Waterborne Environmental, Inc. (WEI). 12 p.

46535603 Registrant 

assessment

Holmes, C. (2005) Proposed Methodology to Redistribute Doane Pesticide Use 

Data Based on NASS 2002 Census of Agriculture Data: (Pyrethroid). Project 

Number: WEI/794/05. Unpublished study prepared by Waterborne 

Environmental, Inc. (WEI). 14 p.

46535604 Registrant 

modeling 

assessment

Ritter, A. (2005) Approach for the Monte Carlo Assessment (Task I) of the 

Sensitivity Analysis of Synthetic Pyrethroid Sediment Exposure Assessments 

to Drift and Runoff Entry Routes. Project Number: WEI/794/05. Unpublished 

study prepared by Waterborne Environmental, Inc. (WEI). 49 p.
78

47944086 Registrant 

assessment

Marks, L. (2009) Comparison of Environmental-Fate Endpoints for AlphaCypermethrin, Cypermethrin and Zeta-Cypermethrin. Project Number: 

2009/7006352/OCR, 2009/7006352. Unpublished study prepared by BASF 

Agro Research. 16 p.
79

Cypermethrin Ecotoxicity Bibliography

71-1 Avian Single Dose Oral Toxicity

MRID Citation Reference

25769 2016140 Ross, D.B.; Cameron, D.M.; Roberts, N.L. (1977) The Acute Oral Toxicity (LD50) 

of PP 383 to the Mallard Duck. (Unpublished study received Dec 31, 1979 under 

10182-EX-19; prepared by Huntingdon Research Centre, submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:241598-G) 

90070 2016174 Roberts, N.L.; Fairley, C. (1980) The Acute Oral Toxicity (LDI50^) of 

Cypermethrin to the Mallard Duck: ICI 302/80305; CTL/8/994. (Unpublished study 

received Dec 30, 1981 under 10182-64; pre- pared by Huntington Research Centre, 

England, submitted by ICI Americas, Inc., Wilmington, Del.; CDL:070561-B) 

44546024 2016193 Johnson, A. (1998) Acute Toxicity (LD50) to Bobwhite Quail: Betacypermethrin: 

Lab Project Number: PWT 129: PWT 129/962076. Unpublished study prepared by 

Huntingdon Life Sciences Ltd. 38 p. 

92027002 Registrant 

Summary

Edwards, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090070. The 

Acute Oral Toxicity (LD50) of Cypermethrin to the Mallard Duck: Report No. 

CTL/C/994; Study No. ICI/302/80305.: 10 p. 

71-2 Avian Dietary Toxicity

MRID Citation Reference

90071 2016164 Roberts, N.L.; Fairley, C.; Woodhouse, R.N. (1980) The Subacute Dietary Toxicity 

(LCI50^) of Cypermethrin to the Mallard Duck: ICI 330/WL/80812; 55 1(a)/3. 

(Unpublished study received Dec 30, 1981 under 10182-64; prepared by 

Hungtindon Research Centre, England, submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL: 070561-C) 

90072 2016165 Roberts, N.L.; Fairley, C.; Woodhouse, R.N. (1981) The Subacute Di- etary 

Toxicity (LCI50^) of Cypermethrin to the Bobwhite Quail: ICI 331 WL/80811; 

5E.1(a)/4. (Unpublished study received Dec 30, 1981 under 10182-64; prepared by 

Huntingdon Research Centre, England, submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL: 070561-D) 

44546025 2016184 Johnson, A. (1998) Dietary (LC50) to the Mallard Duck: Betacypermethrin: Lab 

Project Number: PWT 128: PWT 128/962075. Unpublished study prepared by 

Huntingdon Life Sciences Ltd. 40 p. 

44546026 2016185 Johnson, A. (1998) Dietary LC(50) to the Bobwhite Quail: Betacypermethrin: Lab 

Project Number: PWT 127: PWT 127/962074. Unpublished study prepared by 

Huntingdon Life Sciences Ltd. 40 p. 

92027003 

Of

90072

Registrant 

Summary

Edwards, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090072. The 

Subacute Dietary Toxicity (LC50) of Cypermethrin (PP383) to the Bobwhite Quail: 

Report No. ICI331WL/80811; Study No. ICI331WL/80811. Prepared by 

Huntingdon Research Centre 11 p. 
80

92027004 

Of

90071

Registrant 

Summary

Edwards, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090071. The 

Subacute Dietary Toxicity (LC50) of Cypermethrin (PP383) to the Mallard Duck: 

Report No. ISK/ICIWL284/79835. Prepared by Huntingdon Research Centre 11 p. 

71-4 Avian Reproduction

MRID Citation Reference

90073 DER not 

locatedreviewed in 

1981

Roberts, N.L.; Fairley, C.; Chanter, D.O.; et al. (1981) The Effect of the Dietary 

Inclusion of Cypermentrin on Reproduction in the Mallard Duck: ICI 341/8164; 

CTL/C/1091. (Unpublished study re- ceived Dec 30, 1981 under 10182-64; 

prepared by Huntingdon Re- search Centre, England, submitted by ICI Americas, 

Inc., Wil- mington, Del.; CDL:070561-E) 

90074 2016144 Roberts, N.L.; Fairley, C.; Chanter, D.O.; et al. (1981) The Effect of Dietary 

Inclusion of Cypermethrin on Reproduction in the Bob- white Quail: ICI 

342/81341; CTL/C/1105. (Unpublished study re- ceived Dec 30, 1981 under 10182-

64; prepared by Huntingdon Re- search Centre, England, submitted by ICI 

Americas, Inc., Wil- mington, Del.; CDL:070561-F) 

92027005 Registrant 

Summary

Edwards, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090074. The 

Effect of Dietary Inclusion of Cypermethrin on Reproduction in Bobwhite Quail: 

Report No. CTL/C/1105; Study No.: ICI342/81341.: 15 p. 

92027006 Registrant 

Summary

Edwards, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090073. The 

Effect of the Dietary Inclusion of Cypermethrin on Reproduction in the Mallard 

Duck: Report No. CTL/C/1091; Study No.: ICI341/8164.: 15 p. 

72-1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

62791 See 65812 Hill, R.W.; Maddock, B.G.; Harland, B.J. (1980) Determination of the Acute 

Toxicity of Cypermethrin (PP 383) to Bluegill Sunfish (Lepomis macrochirus): 

BL/B/2011. (Unpublished study received Dec 5, 1980 under 279-EX-86; prepared 

by Imperial Chemical Industries, Ltd., England, submitted by FMC Corp., 

Philadelphia, Pa.; CDL:243861-AE) 

62792 DER not 

locatedReviewed in 

1982

Hill, R.W.; Maddock, B.G.; Harland, B.J. (1980) Determination of the Acute 

Toxicity of Cypermethrin (PP 383) to Rainbow Trout (Salmo gairdneri): 

BL/B/2006. (Unpublished study received Dec 5, 1980 under 279-EX-86; prepared 

by Imperial Chemical Industries, Ltd., England, submitted by FMC Corp., 

Philadelphia, Pa.; CDL:243861-AF) 

65812 2016475 Hill, R.W.; Maddock, B.G.; Harland, B.J. (1980) Determination of the Acute 

Toxicity of Cypermethrin (PP 383) to Bluegill Sunfish (Lepomis macrochirus): 

BL/B/2011. (Unpublished study received Dec 29, 1980 under 10182-EX-19; 

prepared by Imperial Chemical Industries, Ltd., England, submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:244017-D) 

65813 DER not 

locatedHill, R.W.; Maddock, B.G.; Harland, B.J. (1980) Determination of the Acute Toxicity of GFU 061, a 36% w/v Formulation of Cypermethrin to Rainbow Trout 
81

reviewed in 

1981

(Salmo gairdneri): BL/B/2016. (Unpublished study received Dec 29, 1980 under 

10182-EX-19; prepared by Imperial Chemical Industries, Ltd., England, submitted 

by ICI Americas, Inc., Wilmington, Del.; CDL:244017-E) 

65814 DER not 

l.ocated

Hill, R.W.; Maddock, B.G.; Harland, B.J. (1980) Determination of the Acute 

Toxicity of GFU 061, a 36% w/v Formulation of Cypermethrin to Bluegill Sunfish 

(Lepomis macrochirus): BL/B/ 2017. (Unpublished study received Dec 29, 1980 

under 10182-EX- 19; prepared by Imperial Chemical Industries, Ltd., England, 

submitted by ICI Americas, Inc., Wilmington, Del.; CDL:244017-F) 

65816 Permethrin 

study

Hill, R.W.; Young, B.E. (1978) The Acute Toxicity of Permethrin Acid and 3-

Phenoxy Benzyl Alcohol to Rainbow Trout (Salmo gairdneri): BL/B/1918. 

(Unpublished study received Dec 29, 1980 under 10182-EX-19; prepared by 

Imperial Chemical Industries, Ltd., England, submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:244017-J) 

88947 2016176

2079552 = 

contract draft

Hill, R.W.; Maddock, B.G.; Comber, M.H.I. (1981) Cypermethrin: Determination 

of the Acute Toxicity of Formulation GFU 070 to Rainbow Trout (?~Salmo 

gairdneri~?): BL/B/2093. (Unpublished study received Dec 30, 1981 under 10182-

64; prepared by Imperial Chemical Industries, Ltd., submitted by ICI Americas, 

Inc., Wilmington, Del.; CDL:070558-C) 

88948 2016177 Hill, R.W.; Maddock, B.G.; Comber, M.H.I. (1981) Cypermethrin. Determination 

of the Acute Toxicity of Formulation GFU 070 to Bluegill Sunfish (?~Lepomis 

macrochirus~?): BL/B/2099. (Unpub- lished study received Dec 30, 1981 under 

10182-64; prepared by Imperial Chemical Industries, Ltd., submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:070558-D) 

89036 DER not 

located

Reiff, B.; Pearson, N.; Rees, H.J.; et al. (1978) The Effect of Suspended Solids on 

the Toxicity of WL 43467 to Rainbow Trout (?~Salmo gairdneri~?): Group 

Research Report TLGR.0007.78. (Un- published study received Dec 30, 1981 under 

10182-64; prepared by Shell Research, Ltd., England, submitted by ICI Americas, 

Inc., Wilmington, Del.; CDL:070562-A) 

89037 2016146 Hill, R.W.; Young, B.E.; Comber, M.H.I. (1981) Determination of the Acute 

Toxicity of 3-Phenoxy Benzoic Acid to Rainbow Trout (?~Salmo gairdneri~?): 

Brixham Report No. Bl/B/2038. (Unpub- lished study received Dec 30, 1981 under 

10182-64; prepared by Imperial Chemical Industries, Ltd., England, submitted by 

ICI Americas, Inc., Wilmington, Del.; CDL:070562-B) 

89038 2016147 Hill, R.W.; Young, B.E.; Comber, M.H.I. (1981) Determination of the Acute 

Toxicity of 3-Phenoxy Benzoic Acid to Bluegill Sunfish (?~Lepomis 

macrochirus~?): Brixham Report No. BL/B/2086. (Un- published study received 

Dec 30, 1981 under 10182-64; prepared by Imperial Chemical Industries, Ltd., 

England, submitted by ICI Americas, Inc., Wilmington, Del.; CDL:070562-C) 

41068002 Open lit Coats, J.; O'Donnell-Jeffery, N. (1979) Toxicity of four synthetic pyrethroid 

insecticides to rainbow trout. Bulletin of Enviro- mental Contamination and 

Toxicology 23:250-255.

41068003 Open lit McLeese, D.; Metcalfe, C.; Zitko, V. (1980) Lethality of permethrin, cypermethrin 

and fenvalerate to salmon, lobster and shrimp. Bulletin of Environmental 

Contamination and Toxicology 25:950-955.

41068004 Open lit Stephenson, R. (1981) Aquatic toxicology of cypermethrin: I acute toxicology to 

some freshwater fish and invertebrates in labora- tory tests. Aquatic Toxicology 

2:175-185.

41968208 2016167 Overman, M.; Barron, M.; Vaishnav, D. (1990) Cypermethrin-S (FMC 56701): 
82

Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss) Under Flow-through Test 

Conditions: Lab Project Number: 3903026- 0700-3140. Unpublished study prepared 

by Environmental Science and Engineering, Inc. 48 p. 

41968209 2016173 Vaishnav, D.; Yurk, J. (1990) Cypermethrin (FMC 45806): Acute Toxi- city to 

Rainbow Trout (Oncorhynchus mykiss) Under Flow-through Test Conditions: Lab 

Project Number: 3903026-0750-3140. Unpub- lished study prepared by 

Environmental Science and Engineering, Inc. 46 p. 

44546027 2016194 Sousa, J. (1998) (Carbon 14)-Cypermethrin--Acute Toxicity to Rainbow Trout 

(Oncorhynchus mykiss) Under Flow-Through Conditions: Final Report: Lab Project 

Number: 97-11-7166: 12442.1096.6223.108. Unpublished study prepared by

Springborn Labs., Inc. 91 p. 

44546028 2016196 Sousa, J. (1998) Cypermethrin Technical--Acute Toxicity to Rainbow Trout 

(Oncorhynchus mykiss) Under Flow-Through Conditions: Final Report: Lab Project 

Number: 98-1-7213: 12442.1096.6222.108. Unpublished study prepared by 

Springborn Labs., Inc. 78 p. 

44546029 2016186 Sousa, J. (1998) (Carbon 14)(Beta)-Cypermethrin--Acute Toxicity to Bluegill 

Sunfish (Lepomis macrochirus) Under Flow-Through Conditions: Final Report: Lab 

Project Number: 97-12-7177: 12442.1096.6225.105. Unpublished study prepared 

by Springborn Labs., Inc. 91 p. 

44546030 2016187 Sousa, J. (1998) Cypermethrin Technical--Acute Toxicity to Bluegill Sunfish 

(Lepomis macrochirus) Under Flow-Through Conditions: Final Report: Lab Project 

Number: 97-12-7195: 12442.1096.6224.105. Unpublished study prepared by 

Springborn Labs., Inc. 76 p. 

92027007 Registrant 

summary

Adams, D. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00065812.

Cypermethrin Technical PP383: Determination of the Acute Toxicity to Bluegill 

Sunfish (Lepomis macrochirus): Report No. BL/B/2011; Study No.: F342/D. 

Prepared by ICI Brixham Laboratory 13 p. 

92027008 Registrant 

Summary

Adams, D. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089038. 3-

Phenoxybenzoic Acid: Determination of the Acute Toxicity to Bluegill Sunfish 

(Lepomis macrochirus): Report No. BL/2086; Study No.: G145/D.: 12 p 

92027009 Registrant 

Summary

Adams, D. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00088948.

Cypermethrin (PP383): Determination of the Acute Toxicity of a 2lb/US gallon 

formulation to Bluegill Sunfish (Lepomis macrochirus): Report No. BL/B/2099; 

Study No.: G244/C. Prepared by ICI Brixham Laboratory 13 p. 

92027010 Registrant 

Summary

Hill, R. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089037. 3-

Phenoxybenzoic Acid: Determination of the Acute Toxicity of the Active Ingredient 

(99% Purity w/w) to Rainbow Trout (Salmo gairdneri): Report No. BL/B/2038; 

Study No.: G 145/C. Prepared by ICI Brixham Laboratory 12 p. 

92027011 Registrant 

Summary

Treacy, C. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00062792.

Cypermethrin (PP383): Determination of the Acute Toxicity of Active Ingredient 

(91. 5% purity) to Rainbow Trout (Salmo gairdneri) Report No. BL/B/2006; Study 

No.: F342/B.: 12 p. 

92027012 Registrant 

Summary

Coleman, C. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00088947. 

Cypermethrin: Determination of the Acute Toxicity of a 25% w/w Formulation to 

Rainbow Trout (Salbo gairdneri): Report No. BL/B/2093; Study No.: G244/B.: 12 

p. 

92027013 Registrant Treacy, C. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00065813. 
83

Summary Cypermethrin: Determination of the Acute Toxicity of Formulation GFU 061 to 

Rainbow Trout (Salmo gairdneri): Report No. BL/B/2016; S No. F617/B.: 12 p. 

72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

62793 Or

92027014

2016162 Edwards, P.J.; Brown, S.M.; Sapiets, A.S. (1980) Cypermethrin (PP383): Toxicity 

of Technical and Formulated Material to First Instar Daphnia magna: Report Series 

RJ 0110B. (Unpublished study received Dec 5, 1980 under 279-EX-86; prepared 

by Imperial Chemical Industries, Ltd., England, submitted by FMC Corp., 

Philadelphia, Pa.; CDL:243861-AG) 

65815 See 62793 Edwards, P.J.; Brown, S.M.; Sapiets, A.S.; et al. (1980) Cypermethrin (PP383): 

Toxicity of Technical and Formulated Material to First Instar Daphnia magna: 

Report Series RJ 0110B. (Unpublished study received Dec 29, 1980 under 10182-

EX-19; prepared by Imperial Chemical Industries, Ltd., England, submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:244017-H) 

65817 Permethrin study Getty, C.; Wilkinson, W.; Davies, P.J.; et al. (1978) Permethrin Acid and 3-

Phenoxybenzyl Alcohol: Toxicity to First Instar Daphnia magna: Report Series RJ 

0042B. (Unpublished study received Dec 29, 1980 under 10182-EX-19; prepared 

by Imperial Chemical Industries, Ltd., submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:244017-K) 

88949 DER not located Edwards, P.J.; Brown, S.M.; Swaine, H.; et al. (1981) Cypermethrin (PP383): 

Toxicity of Formulation GFU070 to First Instar ?~Daphnia magna~?: Report Series 

RJ 0199B. (Unpublished study received Dec 30, 1981 under 10182-64; prepared by 

Imperial Chemical Industries, Ltd., England, submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070558-E) 

89040 2016162 Edwards, P.J.; Brown, S.M.; Swaine, H.; et al. (1980) Cypermethrin (PP383): 

Toxicity of Formulation GFU061 to First Instar~Daphnia~ ?~magna~?: Report 

Series RJ 0149B. (Unpublished study received Dec 30, 1981 under 10182-64; 

prepared by Imperial Chemical In- dustries, Ltd., submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070562-E) 

89041 2016150 Stephenson, R.R.; Bennett, D.; Francis, W.H.P.; et al. (1980) The Acute Toxicity 

of Cypermethrin (WL 43467) to the Freshwater Shrimp (?~Gammarus pulex~?) 

and Larvae of the Mayfly, (?~Cloeon~ ?~dipterum~?), in Continuous-flow Tests: 

Group Research Report TLGR.80.079. (Unpublished study received Dec 30, 1981 

under 10182-64; prepared by Shell Research, Ltd., England, submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:070562-G) 

89042 DER nor 

locatedreviewed in 

1982-core

Jaber, M.J.; Hawk, R.E. (1981) The Acute Toxicity of Cypermethrin to Crayfish 

(?~Orconectes sp~?.): Report Series TMUE0008/B. (Unpublished study received 

Dec 30, 1981 under 10182-64; sub- mitted by ICI Americas, Inc., Wilmington, 

Del.; CDL:070562-H) 

89046 2016153 Edwards, P.J.; Brown, S.M.; Swaine, H.; et al. (1980) 3-Phenoxy- benzoic Acid: 

Toxicity to First Instar~Daphnia magna~?:Report Series RJ 0148B. (Unpublished 

study received Dec 30, 1981 under 10182-64; prepared by Imperial Chemical 

Industries, Ltd., submitted by ICI Americas, Inc., Wilmington, Del.; CDL:070562-

L) 
84

89048 2016155 Edwards, P.J.; Brown, S.M.; Hamer, M.J.; et al. (1980) Cyper- methrin: Acute 

Toxicity to the Mayfly, Baetis rhodani: Report Series RJ 0173B. (Unpublished 

study received Dec 30, 1981 under 10182-64; prepared by Imperial Chemical 

Industries, Ltd., sub- mitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070562-N) 

140833 2016149 Stephenson, R.R.; Sherwood, C.M.; Bennett, D.; et al. (1980) The Acute Toxicity 

of WL 43467 to Some Freshwater Invertebrates in Static Water Tests: Group 

Research Report TLGR.80.040. (Un- published study received Dec 30, 1981 under 

10182-64; prepared by Shell Research, Ltd., England, submitted by ICI Americas, 

Inc., Wilmington, Del.; CDL:070562-F) 

41068004 Open lit Stephenson, R. (1981) Aquatic toxicology of cypermethrin: I acute toxicology to 

some freshwater fish and invertebrates in labora- tory tests. Aquatic Toxicology 

2:175-185.

41968210 2016168 Ward, T.; Boeri, R. et al. (1991) Acute Toxicity of FMC 56701 Tech- nical and 

Cypermethrin Technical to the Daphnid, Daphnia magna: Lab Project Number: 

90186-FMC: A90-3310. Unpublished study prepared by Resource Analysts, Inc. 

46 p. 

43293501 DER not locatedcontract draft 

available

Wheat, J.; Evans, J. (1994) Zetacypermethrin Technical and Cypermethrin 

Technical: Comparative Acute Toxicity to the Water Flea (Daphnia magna), under 

Flow-Through Test Conditions: Lab Project Number: J9210001B: A92/3636. 

Unpublished study prepared by Toxikon Environmental Sciences. 76 p. 

44074401 DER not located Rapley, J.; Hamer, M. (1996) Cypermethrin: Toxicity to Chironomus riparius and 

Hyalella azteca: Lab Project Number: RC0002: 95JH082. Unpublished study 

prepared by Zeneca Agrochemicals. 15 p. 

44074402 2063977 Gentle, W.; Goggin, U.; Rapley, J.; et al. (1996) Cypermethrin: Toxicity to 

Chironomus tentans in Sediment-Water Systems: Lab Project Number: RC0001: 

96JH007. Unpublished study prepared by Zeneca Agrochemicals. 31 p. 

44074406 2063978 Farrelly, E.; Gentle, W.; Goggin, U.; et al. (1996) Cypermethrin: Toxicity to 

Hyalella azteca in Sediment-Water Systems: Lab Project Number: RC0006: 

95JH228. Unpublished study prepared by Zeneca Agrochemicals. 30 p. 

44423501 DER not located Hamer, M. (1997) Cypermethrin: Acute Toxicity of Short-Term Exposures to 

Hyalella Azteca: Lab Project Number: TMJ3904B. Unpublished study prepared by 

Zeneca Agrochemicals. 10 p. 

44546031 2016188 Putt, A. (1998) (Carbon 14)(Beta)Cypermethrin--Acute Toxicity to Daphnids 

(Daphnia magna) Under Flow-Through Conditions: Final Report: Lab Project 

Number: 97-9-7079: 12442.1096.6227.115. Unpublished study prepared by 

Springborn Labs., Inc. 95 p. 

44546032 2016189 Putt, A. (1998) Cypermethrin Technical--Acute Toxicity to Daphnids (Daphnia 

magna) Under Flow-Through Conditions: Final Report: Lab Project Number: 97-

11-7138: 12442.1096.6226.115. Unpublished study prepared by Springborn Labs., 

Inc. 74 p. 

92027014 Registrant 

Summary

Hamer, M. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00062793. 

Cypermethrin (PP383): Toxicity of Technical and Formulated Material to First 

Instar Daphna (sic) magna: Report No.: RJ011OB; Study No.: PP383/CN/01. 

Prepared by ICI Agrochemicals, Jealott's Hill Research Station. 17 p. 

92027015 Registrant 

Summary

Hamer, M. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089046. 3-

Phenoxybenzoic Acid: Toxicity to First Instar Daphna (sic) magna: Report No.: 
85

RJ0148B; Study No.: PP383/CN/03. Prepared by ICI Agrochemicals, Jealott's Hill 

Research Station. 14 p. 

92027016 Registrant 

Summary

Hamer, M. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00065817. 

Permethrin Acid and 3-Phenoxybenzyl Alcohol: Toxicity to First Instar Daphnia 

Magna: Report No.: RJ0042B; Study No.: PP557/CN/01. Prepared by ICI 

Agrochemicals Jealott's Hill Research Station 18 p. 

92027017 Registrant 

Summary

Hamer, M. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00152739. 3 

Phenoxybenzoic Acid: Toxicity to First Instar Daphnia magna (II): Report No.: 

RJ0318B; PP563/CN/01. Prepared by ICI Agrochemicals Jealott's Hill Research 

Station 14 p. 

31225 DER not located Leblanc, G.A. (1976) Acute Toxicity of FMC-30980 to Daphnia magna: ACT 

011.12. (Unpublished study received Sep 28, 1976 under 279-EX-63; prepared by 

EG&G, Bionomics, submitted by FMC Corp., Philadelphia, Pa.; CDL:227762-E) 

152739 2016175 Everett, C.J., M.J. Hamer and I.R. Hill (1983) 3-Phenoxybenzoic Acid: Toxicity to 

First Instar Daphnia magna

72-3 Acute Toxicity to Estuarine/Marine Organisms

(II). Report Series RJ 0318B. Prepared and Submitted 

by ICI Plant Protection Division, Bracknell, Berkshire, England. EPA MRID No. 

152739.

MRID Citation Reference

89043 2016151

2016161

Jaber, M.J.; Hawk, R.E. (1981) The Acute Toxicity of Cypermethrin to Pink Shrimp 

(Penaeus duorarum): Report Series TMUE004/B. (Unpublished study received Dec 

30, 1981 under 10182-64; sub- mitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070562-I) 

89044 2016166 Jaber, M.J.; Hawk, R.E. (1981) The Acute and Chronic Toxicity of Cypermethrin to 

Mysid Shrimp (?~Mysidopsis bahia~?): Report Series TMUE0005/B. (Unpublished 

study received Dec 30, 1981 under 10182-64; submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070562-J) 

89045 2016152 Jaber, M.J.; Hawk, R.E. (1981) The Acute Toxicity of Cypermethrin to Fiddler 

Crabs (?~Uca pugilator~?): Report Series TMUE0003/B. (Unpublished study 

received Dec 30, 1981 under 10182-64; sub- mitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070562-K) 

89049 2016154 Jaber, M.J.; Hawk, R.E. (1981) The Acute Toxicity of Cypermethrin to Eastern 

Oysters (Crassostrea virginica): Report Series TMUE0009/B. (Unpublished study 

received Dec 30, 1981 under 10182-64; submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070562-O) 

89050 2016143 Hill, R.W.; Thompson, R.S.; Comber, M.H.I. (1981) Investigation of the Acute 

Toxicity of PP 383 to Larvae of the Pacific Oyster (Crassostrea gigas): Brixham 

Report No. BL/B/2088. (Unpub- lished study received Dec 30, 1981 under 10182-

64; prepared by Imperial Chemical Industries, Ltd., England, submitted by ICI 

Americas, Inc.; Wilmington, Del.; CDL:070562-P) 

90075 DER not 

located

Jaber, M.J.; Hawk, R.E. (1981) The Acute Toxicity of Cypermethrin to Sheepshead 

Minnows (?~Cyprinodon variegatus?~): Report Series TMUE0002/B. (Unpublished 

study received Dec 30, 1981 under 10182-64; submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:079561-G) 
86

41968211 2016171 Overman, M.A., M.G. Barron and D.D. Vaishnav (1990) Cypermethrin-S (FMC 

56701): Acute Toxicity to Sheepshead Minnow (Cyprinodon variegates) under 

Flow-Through Test Conditions. Laboratory Project No. 3903026-0600-3140. Study 

Performed by Environmental Science and Engineering, Inc., Gainesville, FL. 

Submitted by FMC Corporation, Philadelphia, PA. EPA MRID No. 31968211.

41968212 2016170 Chandler, A. (1990) FMC 45806: Acute Toxicity to Sheepshead Minnow 

(Cyprinodon variegatus) Under Flow-through Test Conditions: Lab Project 

Number: 3903026-0350-3140. Unpublished study prepared by Environmental 

Science and Engineering(ESE), Inc. 43 p. 

41968213 2016169 Ward, T.; Boeri, R. (1991) Acute Toxicity of FMC 56701 Technical and 

Cypermethrin Technical to the Mysid, Mysidopsis bahia: Lab Project Number: 

90187-FMC: A90-3309. Unpublished study prepared by Resource Analysts, Inc. 52 

p. 

42364701 Registrant 

rebuttal

Anon. (1992) Response to the EPA's Review of MRID 41968212 Cypermethrin: 

Acute Toxicity to Sheepshead Minnows Under Flow-Through Test Conditions: 

Unpublished study prepared by FMC Corp. 8 p. 

44546033 2016195 Dionne, E. (1998) Cypermethrin Technical--Acute Toxicity to Sheepshead Minnow 

(Cyprinodon variegatus) Under Flow-Through Conditions: Final Report: Lab 

Project Number: 97-12-7197: 12442.1096.6230.505. Unpublished study prepared 

by Springborn Labs., Inc. 75 p. 

44546034 2016187 Sousa, J. (1998) (Carbon 14)(Beta)-Cypermethrin--Chronic Toxicity to Sheepshead 

Minnow (Cyprinodon variegatus) Under Flow-Through Conditions: Final Report: 

Lab Project Number: 97-1-7212: 12442.1096.6231.505. Unpublished study 

prepared by Springborn Labs., Inc. 91 p.

44561209 2016191 Putt, A. (1998) (Carbon-14) Beta-Cypermethrin--Acute Toxicity to Mysids 

(Mysidopsis bahia) Under Flow-Through Conditions: Final Report: Lab Project 

Number: 97-11-7153: 12442.1096.6229.515. Unpublished study prepared by 

Springborn Laboratories, Inc. 79 p. 

44561210 2016190 Putt, A. (1998) Cypermethrin Technical--Acute Toxicity to Mysids (Mysidopsis 

bahia) Under Flow-through Conditions: Final Report: Lab Project Number: 98-1-

7224: 12442.1096.6228.815. Unpublished study prepared by Springborn 

laboratories, Inc. 76 p. 

92027018 Registrant 

Summary

Royal, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00090075. 

Cypermethrin: Acute Toxicity of Technical Material for Sheepshead Minnow 

(Cyprinodon variegatus): Report No.: TMUE 0002/B.: 15 p. 

92027019 Registrant 

Summary

Royal, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089049. 

Cypermethrin: The Acute Toxicity to Eastern Oysters (Crassostrea virginica): 

Report No. TMUE 0009/B. Prepared by Springborn Laboratories, Inc. 13 p. 

92027020 Registrant 

Summary

Royal, P. (1990) Ici Americas Inc. Phase 3 Summary of MRID 00089043. 

Cypermethrin: Determination of the Acute Toxicity of Technical Material to Pink 

Shrimp (Penaeus duorarum): Report No. TMUE 0004/B. Prepared by Springborn 

Laboratories, Inc. 15 p. 

92027021 2016166 

Registrant 

Summary

Royal, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089044. 

Cypermethrin: Determination of Acute Toxicity to Mysid Shrimp (Mysidopsis 

bahia): Report No. TMUE 0005/B. Prepared by Springborn Laboratories, Inc. 12 p. 

92027022 Registrant 

Summary

Royal, D. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089045. 

Cypermethrin: Determination of the Acute Toxicity of Technical Material to the 
87

Fiddler Crab (Uca pugilator): Report No. TMUE 0003/B. Prepared by Springborn 

Laboratories, Inc. 15 p. 

89051 Stability test Ussary, J.P.; Fitzpatrick, R.D.; Foreman, L.A.; et al. (1981) Cy- permethrin Stability 

in Marine Laboratory Test Systems: Report Series TMU0558/B. (Unpublished 

study received Dec 30, 1981 under 10182-64; submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:070562-Q) 

46591503 Contract draft 

available

Putt, A. (2005) Cypermethrin - Toxicity to Estuarine Amphipods (Leptocheirus 

plumulosus) During a 28-Day Sediment Exposure. Project Number: 13656/6111. 

Unpublished study prepared by Springborn Smithers Laboratories. 85 p.

Accession 

No.

070562

2016143

2016156

Thompson, R.S. (1981) Investigation of the Acute Toxicity of PP383 to Larvae of 

the Pacific Oyster (Crassostrea gigas

42444601

). Unpublished Report by the Brixham 

Laboratory of Imperial Chemical Industries, Ltd., Submitted 12/28/81 by ICI 

Americas Inc., Wilmington, Delaware.

2016178

2016179

Ward, Timothy J., Robert L. Boeri and Mark A. Palmieri (1992) Acute Toxicity of 

FMC 56701 Technical and Cypermethrin Technical to the Mysid, Mysidopsis

bahia. FMC Study Number A91-3454. Submitted by FMC Corporation. Performed 

by EnviroSystems Division, Resource Analysts, Inc. Hampton, New Hampshire. 

MRID No. 42444601.

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID Citation Reference

25770 2016141 Hill, R.W.; Maddock, B.G.; Hart, B. (1976) Determination of the Acute Toxicity of 

PP383 to Rainbow Trout (Salmo gairdnerii): Report No. BL/B/1711. (Unpublished 

study received Dec 31, 1979 under 10182-EX-19; prepared by Imperial Chemical 

Industries, Ltd., submitted by ICI Americas, Inc., Wilmington, Del.; CDL: 241598-

H) 

25771 2016142 Hill, R.W.; Maddock, B.G.; Hart, B.; et al. (1977) Determination of the Acute 

Toxicity of PP 383 to Bluegill Sunfish (Lepomis macrochirus): Report No. 

BL/B/1775. (Unpublished study received Dec 31, 1979 under 10182-EX-19; 

prepared by Imperial Chemical Industries, Ltd., submitted by ICI Americas, Inc., 

Wilmington, Del.; CDL:241598-I) 

31224 DER not 

located

Bentley, R.E. (1976) Acute Toxicity of FMC-30980 to Bluegill (Lepomis 

macrochirus): NCT 634.61. (Unpublished study received Sep 28, 1976 under 279-

EX-63; prepared by EG&G, Bionomics, submitted by FMC Corp., Philadelphia, 

Pa.; CDL:227762-D) 

89039 2016148 Jaber, M.J.; Hawk, R.E. (1981) The Toxicity of Cypermethrin to Fathead Minnow 

(Pimephales promelas) Embryos and Larvae: Report Series TMUE0007/B. 

(Unpublished study received Dec 30, 1981 under 10182-64; submitted by ICI 

Americas, Inc., Wilmington, Del.; CDL:070562-D) 

89047 2016163 Edwards, P.J.; Hamer, M.J.; Bull, J.M.; et al. (1981) Cypermethrin: 21 

Day~Daphnia magna~Life Cycle Study: Report Series RJ 0177B. (Unpublished 

study received Dec 30, 1981 under 10182-64; pre- pared by Imperial Chemical 

Industries, Ltd., submitted by ICI Americas, Inc., Wilmington, Del.; CDL:070562-

M) 
88

42725301 2016180 Wheat, J. (1993) FMC-30980(carbon 14)-Cypermethrin: Chronic Toxicity to the 

Mysid, Mysidopsis bahia, Under Flow-Through Test Conditions: Lab Project 

Number: J9205004A. Unpublished study prepared by Toxikon Environmental 

Sciences. 63 p. 

42898301 2016182 Wheat, J. (1993) FMC-30980 ((carbon 14) labeled Cypermethrin): Chronic LifeCycle Toxicity to the Water Flea, Daphnia magna, Under Flow-through Test 

Conditions: Lab Project Number: J9205004B: A91-3479. Unpublished study 

prepared by Toxikon Environmental Sciences. 71 p. 

44546035 2016192 Sousa, J. (1998) (Carbon 14)(Beta)-Cypermethrin--Chronic Toxicity to Mysids 

(Mysidopsis bahia) Under Flow-Through Conditions: Final Report: Lab Project 

Number: 97-12-7170: 12442.1096.6232.530. Unpublished study prepared by 

Springborn Labs., Inc. 101 p. 

92027023 Registrant 

Summary

Royal, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089039. 

Cypermethrin: Early Life Stages Test Fathead Minnow (Pimephales promelas): 

Report No. TMUE 0007/B. Prepared by Springborn Laboratories, Inc. 14 p. 

92027024 Registrant 

Summary

Royal, P. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089044. 

Cypermethrin: Invertebrate Life-Cycle Test in Mysid Shrimp (Mysidopsis bahia): 

SLI TMUE 0005/B.: 16 p 

92027025 Registrant 

Summary

Hamer, M. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00089047. 

Cypermethrin: 21 Day Daphnia magna Life-cycle Study: Report No.: RJ0177B; 

PP383/CN/04. Prepared by ICI Agrochemicals Jealott's Hill Research Station 17 p. 

46591503 2086352 Marine Amphipod 28 Day Whole Sediment toxicity 

850.1300 Daphnid chronic toxicity test

MRID Citation Reference

47885103 Contract draft 

available

Cafarella, M. (2008) Cypermethrin: Full Life Cycle Toxicity Test with Water Fleas, 

Daphnia magna under Flow-Through Conditions: Reformatted Final Report. Project 

Number: 1084/012/231, A2007/6309. Unpublished study prepared by Springborn 

Smithers Laboratories (Europe). 87 p.

47944027 DER not 

located

Garforth, B. (1982) WL 85871 and Cypermethrin: Chronic Toxicity to Daphnia 

magna. Project Number: AL/523/001/OCR, AL/523/001, SBGR/82/119. 

Unpublished study prepared by Sittingbourne Research Center. 46 p.

72-5 Life cycle fish

MRID Citation Reference

40102101 Status report Hill, R.; Tapp, J. (1987) Status Report at Day 30 Post-hatch Cypermethrin (PP383) 

Fathead Minnow Lifecycle Study: Lab. Pro- ject ID: (P171/C). Unpublished study 

prepared by Imperial Chem- ical Industries PLC, Brixham Laboratory. 7 p. 
89

40427901 Status report Hill, R.; Tapp, J. (1987) Status Report on Cypermethrin (PP383) Fathead Minnow 

Lifecycle Study (P171/C): Laboratory Project ID P171/C. Unpublished study 

prepared by Imperial Chemicals Industries PLC. 13 p. 

40529601 Status report Hill, R.; Tapp, J. (1988) Status Report of Cypermethrin (PP383) Fathead Minnow 

Lifecycle Study (P171/c). Laboratory Project ID P171/C. Unpublished study 

prepared by Imperial Chemicals Industries PLC, England. 4 p. 

40641701 DER not 

located

Tapp, J.; Hill, R.; Maddock, B.; et al. (1988) "Cypermethrin: Determination of 

Chronic Toxicity to Fathead Minnow (Pimephales promelas) Full Lifecycle": 

Laboratory Project ID BL/B/3173. Unpublished study prepared by ICI PLC, 

Brixham Laboratory. 189 p. 

41092101 addendum Tapp, J. (1988) Cypermethrin: Determination of Chronic Toxicity to Fathead 

Minnow (Pimephales Promelas) Full Lifecycle. Addendum to Brixham Laboratory 

Report No. BL/B/3173: Laboratory ID No. FT5/86/P171/C. Unpublished study 

prepared by ICI Brixham Labor- atory. 12 p. 

92027026 Registrant 

summary

Adams, D. (1990) ICI Americas Inc. Phase 3 Summary of MRID 40641701. 

Cypermethrin: Determination of the Chronic Toxicity to Fathead Minnow 

(Pimephales promelas): Report Nos. BL/B/3173/3507; Study No. P171/C.: 19 p. 

40102100 Interim report Imperial Chemical Industries PLC (1987) Interim Report on Fish Lifecycle Study of 

Cypermethrin in Response to Data Call-in Notice. Compilation of 1 study. 

72-6 Aquatic org. accumulation

MRID Citation Reference

42868203 Check Fate 

Data

Giroir, E.; Stuerman, L. (1993) Cypermethrin (carbon 14) Bioconcentration by 

Bluegill Sunfish (Lepomis macrochirus): Lab Project Number: 191E5491E1: 

40018: PC-0189. Unpublished study prepared by ABC Labs, Inc. 311 p. 

72-7 Simulated or Actual Field Testing

MRID Citation Reference

40125601 Suitability 

evaluation

Cole, J.; Brantly, T.; Hodges, J.; et al. (1987) Cypermethrin: Evaluation during 1986 

of "Speir II" (Alabama, USA) Farm Pond Drainage Basin and Ecosystem for 

Suitability for a 1987 Cyper- methrin Study: I: Laboratory Project ID: RJ0553B. 

Unpublished study prepared by Imperial Chemical Industries. 382 p. 

40125602 Suitability 

evaluation

Cole, J.; Brantly, T.; Hodges, J.; et al. (1987) Cypermethrin: Evaluation during 1986 

of "Mayo" (Alabama, USA) Farm Pond Drain- age Basin and Ecosystem for 

Suitability for a 1987 Cypermethrin Study: I: Laboratory Project ID: RJ0557B. 

Unpublished study prepared by Imperial Chemical Industries. 376 p. 

40125603 Suitability 

evaluation

Hill, I.; Cole, J. (1987) Comparison of "Speir II" and "Mayo" Farm Ponds

(Alabama) USA: Laboratory Project ID: M4428B. Unpublished study prepared by 
90

Imperial Chemical Industries. 20 p. 

40804501 2016160 Rea, D.; Brantly, T.; Grimmett, J.; et al. (1988) Cypermethrin: Evaluation of the 

Impact of Aerially Sprayed Cypermethrin on the Aquatic Ecosystem of a Farm 

Pond in the Drainage Basin of a Cotton Crop: 1987: Laboratory Project ID 

RH0629B. Unpublished study prepared by ICI Agrochemicals. 744 p. 

40804502 Suitability 

evaluation

Cole, J.; Brantly, T.; Hodges, J.; et al. (1988) Cypermethrin: Evaluation during 1986 

of "Speir II" (Alabama, USA) Farm Pond Drainage Basin and Ecosystem for 

Suitability for a 1987 Cypermethrin Study: II: Laboratory Project ID RJ0591B. 

Unpub- lished study prepared by ICI Agrochemicals. 508 p. 

41011501 addendum Sadler, J. (1989) Cypermethrin: Addendum to RJ0629B: Evaluation of the Impact 

of Aerially Sprayed Cypermethrin on the Aquatic Eco- system of a Farm Pond in 

the Drainage Basin of a Cotton Crop: 1987: Project ID: PP383-CF-04/2. 

Unpublished study prepared by Jeallot's Hill Research Station. 14 p. 

41218801 Progress report Palmieri, M. (1989) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Rept. 1: Study No. A89-2847. 

Unpublished study prepared by Wildlife International, Ltd. 17 p. 

41336201 Progress report Palmieri, M. (1989) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 3: FMC Study No. A89-2847. 

Unpublished study prepared by Wildlife International, Ltd. and FMC Corp. 5 p. 

41403101 Progress report Palmieri, M. (1990) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 4: Lab Project Number: A89-

2847. Unpublished study prepared by Wildlife International, Ltd. in association 

with FMC Corp. 55 p. 

41466301 Progress report Palmieri, M. (1990) Aquatic Mecocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report. Unpublished study prepared by 

Wildlife International, Ltd. 7 p. 

41541101 Progress report Palmieri, M. (1990) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 6: Lab Project No. A89-2847. 

Unpublished study prepared by Wildlife International, Ltd. 14 p. 

41616201 Progress report Palmieri, M. (1990) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 7: Project Number: A89-2847. 

Unpublished study prepared by Wildlife International, Ltd., and FMC Corp. 14 p. 

41670701 Progress report Palmeri, M. (1990) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 8: Lab Project Number: A89-

2847. Unpublished study prepared by Wildlife International, Ltd., and FMC Corp. 

14 p. 

41732501 Progress report Palmieri, M. (1990) Aquatic Mesocosm Study of Pesticide Product Containing the 

Active Ingredient Cypermethrin: Progress Report 9: Project Number: A89-2847. 

Unpublished study prepared by Wildlife International, Ltd and FMC Corp. 13 p. 

41800601 Progress report Palmieri, M. (1991) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 10. Lab Project Number: A89-

2847. Unpublished study prepared by Wildlife International, Ltd. and FMC Corp. 

12 p.

41862501 Progress report Palmieri, M. (1991) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 11: Lab Project Number: A89-

2847. Unpublished study prepared by Wildlife International, Ltd. & FMC Corp. 58 

p. 
91

42148201 DER not 

located

Palmieri, M.; Freda, J.; Krueger, H.; et al. (1991) An Evaluation of the Impact of 

Cypermethrin Exposure on Managed Aquatic Ecosystems: Lab Project Number: 

104-160: A89-2847. Unpublished study prepared by Wildlife International Ltd. 

1612 p.

40125604 Protocol Hill, I. (1987) Protocol--Cypermethrin: A Study of the Impact of Aerially Sprayed 

Cypermethrin on the Aquatic Ecosystem of a Farm Pond in the Drainage Basin of a 

Cotton Crop: Laboratory Project ID: 383/CF/04. Unpublished study prepared by 

Imperial Chemical Industries. 31 p. 

40967301 Addendum Sadler, J.; Hill, I. (1989) Cypermethrin: Addendum to RJ0629B ...; Evaluation of 

the Impact of Aerially Sprayed Cypermethrin on the Aquatic Ecosystem of a Farm 

Pond in the Drainage Basin of a Cotton Crop; 1987: Project ID; PP383-CT-04/1. 

Unpublished study prepared by ICI Agrochemicals. 11 p. 

41293901 Progress report Palmieri, M. (1989) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 2: Lab Project Number: 

A89/2847. Unpublished study prepared by Wildlife International, Ltd. in 

Association with FMC Corp. 5 p. 

42081101 Progress report Palmieri, M. (1991) Aquatic Mesocosm Study of Pesticide Products Containing the 

Active Ingredient Cypermethrin: Progress Report 14: Lab Project Number: A89-

2847. Unpublished study prepared by Wildlife International, Ltd. and FMC Corp. 8 

p. 

Acc No.

250506

128704

2016157 Jaber, M.; Hawk, R. (1983) Cypermethrin: Aquatic Ecological Effects under Field 

Use Conditions in Cotton: Selma, Alabama, 1980: Re- port Series TMUE0026/B. 

(Unpublished study received Mar 24, 1983 under 10182-65; submitted by ICI 

Americas, Inc., Wilming- ton, DE; CDL:250506-A)

152737 DER not 

located

Getty, C.; Wilkinson, W.; Swaine, H.; et al. (1983) Cypermethrin: Effects of 

Multiple Low Rate Applications on Experimental Ponds: Report No. RJ0182B. 

Unpublished study prepared by Imperial Chemical Industries PLC. 62 p. 

155770 Open lit Crossland, N. (1982) Aquatic toxicology of cypermethrin. II. Fate and biological 

effects in pond experiments. Aquatic Toxicology 2:205-222. 

155772 Open lit Crossland, N.; Shires, S.; Bennett, D. (1982) Aquatic toxicolofy of cypermethrin. 

III. Fate, and biological effects of spray drift deposits in fresh water adjacent to 

agricultural land. Aquatic Toxicology 2:253-270. 

141-1 Honey bee acute contact

MRID Citation Reference

155740 2016158 Bull, J.; Wilkinson, W. (1980) Cypermethrin: Laboratory Determina- tion of the 

Acute Toxicity to Honeybees of Technical Material and an Emulsifiable 

Concentrate (GFU 061): Report Series: RJ 0169B. Unpublished study prepared by 

ICI Plant Protection Div. 35 p. 

44544208 2016183 Halsall, N. (1998) Betacypermethrin 10 EC: Acute Toxicity to Honey Bees (Apis 

mellifera): Lab Project Number: PWT 131/963589: PWT 131. Unpublished study 

prepared by Huntingdon Life Sciences Ltd. 29 p. 

92027047 Registrant 

Summary

Lewis, G. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00155740. 

Cypermethrin: Acute Contact and Oral Toxicity to Honey Bees (Apis mellifera: 
92

Report No. RJ0169B; Study No.: PP383/CM/01. Prepared by ICI Agrochemicals 

Jealott's Hill Research Station. 14 p. 

92027048 Registrant 

Summary

Lewis, G. (1990) ICI Americas Inc. Phase 3 Summary of MRID 40274001. 

Cypermethrin: Toxicity of Residues on Foliage to Honey Bees (Apis mellifera): 

Report No. RJ0587B; Study No.: PP383CM03. Prepared by ICI Agrochemicals 

Jealott's Hill Research Station. 13 p. 

47800504 Open lit- DER 

not located

Decourtye, A.; Devillers, J.; Genecque, E.; et al. (2005) Comparative Sublethal 

Toxicity of Nine Pesticides on Olfactory Learning Performances of the Honeybee 

Apis mellifera. Archives of Environmental Contamination and Toxicology 

48:242-250.

47800530 Open lit- DER 

not located

Chauzat, M.; Carpentier, P.; Martel, A.; et al. (2009) Influence of Pesticide 

Residues on Honey Bee (Hymenoptera: Apidae) Colony Health in France. Environ. 

Entomol. 38(3):514-523.

141-2 Honey bee residue on foliage

MRID Citation Reference

40274001 2016159 Gough, H.; Jackson, D.; Wilkinson, W. (1987) Cypermethrin: Toxicity of Residues 

on Foliage to Honey Bees (Apis mellifera): Laborato- ry Project ID: RJ0587B. 

Unpublished study prepared by ICI Plant Protection Division. 27 p. 

41699401 Registrant 

summary

Lewis, G. (1990) Phase 3 Summary of MRID 40274001: Cypermethrin: Toxicity 

of Residues on Foliage to Honey Bees (Apis mellifera): Lab Project Number: 

RJ0587B: PP383CM03. Unpublished study pre- pared by ICI Agrochemicals, 

Jealotts Hill Research Station. 13 p. 

141-3 Toxicity to Non Target Insects

5009995 Open lit

2079040

Waddill, V.H. (1978) Contact toxicity of four synthetic pyrethroids and methomyl 

to some adult insect parasites. Florida Entomologist 61(1):27-30. 

127368 Open lit Harris, C.; Turnbull, S. (1978) Laboratory studies on the contact toxicity and 

activity in soil of four pyrethroid insecticides. Canadian Entomologist 

110(Mar):285-288. (Submitter AW-81-0099; also In unpublished submission 

received Apr 8, 1983 under 39398- 16; submitted by Sumitomo Chemical America, 

Inc., New York, NY; CDL:249939-B) 

850.1790 Chironomid Sediment Toxicity Test

MRID Citation Reference

46871501 Summary of 

multiple studies

Giddings, J. (2006) Overview of Sediment Toxicity Studies with Synthetic 

Pyrethroids. Project Number: 06723, 06273. Unpublished study prepared by 
93

Compliance Services International. 62 p.

850.7100 Data reporting for environmental chemistry methods

MRID Citation Reference

47053001 DER not 

located

Robinson, N. (2007) Residue Analytical Method for the Determination of Residues 

of Bifenthrin, Cypermethrin, Cyfluthrin, Deltamethrin, Esfenvalerate, 

Fenpropathrin, Lambda-cyhalothrin and Permethrin in Sediment. Unpublished study 

prepared by Syngenta Jealotts Hill International. 185 p.

47053002 DER not 

located

Reed, R. (2006) Laboratory Validation: Validation of the Residue Analytical 

Method: Residue Analytical Method for the Determination of Residues of 

Bifenthrin, Cypermethrin, Cyfluthrin, Deltamethrin, Esfenvalerate, Fenpropathrin, 

Lambda - Cyhalothrin and Permethrin in Sediment: Final Report. Project Number: 

MLI/06/02, ML06/1286/PWG. Unpublished study prepared by Morse Laboratories 

Inc. 418 p.

850.1735 Whole sediment: acute freshwater invertebrates

MRID Citation Reference

47946601 Contract draft 

available

Picard, C. (2009) 10-Day Toxicity Test Exposing Freshwater Amphipods (Hyalella 

azteca) to Cypermethrin Applied to Glen Charlie Pond Sediment Under StaticRenewal Conditions. Project Number: 13656/6130, 

100808/OPPTS/10/DAY/HYALELLA/MA/SED. Unpublished study prepared by 

Springborn Smithers Laboratories. 117 p.

47946602 Contract draft 

available

Picard, C. (2009) 10-Day Toxicity Test Exposing Freshwater Amphipods (Hyalella 

azteca) to Cypermethrin Applied to Formulated Sediment Under Static-Renewal 

Conditions. Project Number: 13656/6129. Unpublished study prepared by 

Springborn Smithers Laboratories. 118 p.

47946603 Contract draft 

available

Picard, C. (2009) 10-Day Toxicity Test Exposing Freshwater Amphipods (Hyalella 

azteca) to Cypermethrin Applied to California Sediment 2 Under Static-Renewal 

Conditions. Project Number: 13656/6127. Unpublished study prepared by 

Springborn Smithers Laboratories. 119 p.

47946604 Contract draft 

available

Picard, C. (2009) 10-Day Toxicity Test Exposing Freshwater Amphipods (Hyalella 

azteca) to Cypermethrin Applied to CA Sediment 1 Under Static-Renewal 

Conditions. Project Number: 13656/6126. Unpublished study prepared by 

Springborn Smithers Laboratories. 118 p.

47946605 Contract draft 

available

Picard, C. (2009) 10-Day Toxicity Test Exposing Freshwater Amphipods (Hyalella 

azteca) to Cypermethrin Applied to California Sediment 3 Under Static-Renewal 

Conditions. Project Number: 13656/6128, 

100808/OPPTS/10/DAY/HYALELLA/CAS3. Unpublished study prepared by 

Springborn Smithers Laboratories. 116 p.
94

46591504 2086351 Putt, A. (2005) Cypermethrin - Toxicity to Midge (Chironomus tentans) During a 

10-Day Sediment Exposure. Project Number: 13656/6110. Unpublished study 

prepared by Springborn Smithers Laboratories. 88 p.

46725701 2086353 Putt, A. (2005) Cypermethrin - Life-Cycle Toxicity Test with Midge (Chironomus 

tentans) During a 60-Day Sediment Exposure. Project Number: 13656/6112. 

Unpublished study prepared by Springborn Smithers Laboratories. 117 p.

Non Guideline Selections

90000 2016265 

summary pg 29

Brown, S.M.; Edwards, P.J. (1980) Cypermethrin (PP383): Effects on 

Earthworms,~Lumbricidae?~: Report Series RJ 0151B. (Unpublished study 

received Dec 30, 1981 under 10182-64; prepared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070559-O) 

90001 2016265 

summary pg 29

Cole, J.F.H.; Wilkinson, W. (1980) Cypermethrin (PP383): Effects on Soil 

Microarthropods: Report Series RJ 0150B; 5B 4/6. (Unpub- lished study 

received Dec 30, 1981 under 10102-64; prepared by Imperial Chemical 

Industries, Ltd., England, submitted by ICI Americas, Inc., Wilmington, Del.; 

CDL:070559-P) 

90059 2016265 

summary pg 56

2016265 

summary pg 57

Curl, E.A.; Milner, S.D. (1980) Cypermethrin: Accumulation and De- pletion 

of Radioactive Residues in the Tissues of Mallard Duck and Bobwhite Quail 

following Daily Dosing: Report Series RJ 0147B. (Unpublished study received 

Dec 30, 1981 under 10182-64; prepared by Imperial Chemical Industries Ltd., 

England, submit- ted by ICI Americas, Inc., Wilmington, Del.; CDL:070560-

K) 

Leahey 1977. Similar study with Permethrin and Mallard and Japanese Quail

138935 DER not 

located

Hill, I. (1984) A Review of the Effects of Pyrethrum and Synthetic Pyrethroids 

on Non-target Organisms in Terrestrial and Aquatic Environments: Report 

Series RJ0349B. (Unpublished study re- ceived Jan 30, 1984 under 10182-65; 

prepared by Imperial Chemi- cal Industries, Ltd., Eng., submitted by ICI 

Americas, Inc., Wilmington, DE; CDL:252348-A) 

149692 DER not 

located

Rajakulendran, S.; Plapp, F. (1982) [Comparative Toxicities of Five Synthetic 

Pyrethroids to Various Parasites and Predators]. Un- published compilation. 8 

p. 

149693 DER not 

located

Zoecon Corp. (1983) Effects on Pollinators:[Fluvalinate]. Unpub- lished 

compilation. 15 p. 

155785 Open lit Stephenson, R.; Choi, S.; Olmos-Jerez, A. (1984) Determining the toxicity and 

hazard to fish of a rice insecticide. Crop Protec- tion 3(2):151-165.

155797 Check SETAC 

publications

Hill, I.; Hamer, M. (1984) The Influence of Adsorption and Degradation on the 

Toxicity of Permethrin, Cyperthrin and Cyhalothrin to Aquatic Organisms. 

Unpublished documents presented at the SETAC Fifth Annual Meeting, 

November, 1984; Washington, D.C. 2 p.

40135801 DER not 

located

Kaminski, B. (1987) Cypermethrin: Effect on Earthworms and Bioaccumulation Potential of Residues. Unpublished study prepared by ICI 

Americas. 7 p. 

40135802 DER not 

located

Arnold, J.; Edwards, P. (1983) Cypermethrin: Effects on Earthworms 

Lumbricidae of Repeated Annual Field Applications: Lab Project ID: RJ0311B. 
95

Unpublished study prepared by ICI Plant Protec- tion Division. 36 p. 

40135803 DER not 

located

Curl, E.; Leahey, J. (1984) Permethrin and Cypermethrin: Character- isation of 

Radioactive Residues Found in Earthworms Which Have Been Exposed to Soil 

Treated with [Carbon 14]-Permethrin and [Carbon 14]-Cypermethrin: Lab 

Project ID: RJ0343B. Unpublished study prepared by ICI Plant Protection 

Division. 36 p. 

40135804 DER not 

located

Edwards, P.; Arnold, J. (1984) Cypermethrin and Permethrin: Accumu- lation 

of [Carbon 14]-Cypermethrin and [Carbon 14]-Permethrin Equivalents by the 

Earthworms Allolobophora calliginosa and Lum- bricus terrestris: Lab Project 

ID: RJ0341B. Unpublished study prepared by ICI Plant Protection Division. 30 

p. 

40135805 DER not 

located

Collis, W.; Leahey, J. (1984) Cypermethrin: Evaluation of Bio- accumulation 

Potential in Quail Dosed with Earthworms Containing Cypermethrin Derived 

Residues: Lab Project ID: RJ0330B. Unpub- lished study prepared by ICI Plant 

Protection Division. 35 p. 

40135806 DER not 

located

Cavell, R.; Leahey, J.; Lloyd, S. (1984) Cypermethrin: Evaluation of 

Bioaccumulation Potential in Rats Dosed with Earthworms Con- taining 

Cypermethrin Derived Residues: Lab. Project ID: RJ0352B. Unpublished study 

prepared by ICI Plant Protection Division. 35 p. 

40135807 DER not 

located

Leahey, J.; Curl, E.; Edington, C.; et al. (1985) Permethrin and Cypermethrin: 

Identification of a Major Component of the Radio- active Residue in 

Earthworms Exposed to Soil Treated with [Carbon-14]-Benzyl-labeled 

Cypermethrin (Addendum to RJ0343B): Lab Project No.: RJ0391B. 

Unpublished study prepared by ICI Plant Protection Division. 21 p. 

40359505 Open lit 

DER not 

located 

Watters, F.; White, N.; Cote, D. (1983) Effect of temperature on toxicity and 

persistence of three pyrethroid insecticides applied to fir plywood for the 

control of the red flour beetle (coleoptera: Tenebrionidae. Journal of 

Economic Entomology 76: 11-16.

44388401 Registrant 

Assessment

Maund, S.; Travis, K.; Hendley, P.; et al. (1997) Evaluation of the Ecological 

Risks of Cotton Pyrethroids to Aquatic Ecosystems: Lab Project Number: 

RC0009B. Unpublished study prepared by Zeneca Agrochemical (Zeneca 

Ltd.). 30 p. 

44396501 Registrant 

Assessment

Solomon, K. (1997) Review of the Laboratory Aquatic Organism Toxicity Data 

for the Cotton Pyrethroids: Distributional Analysis of the Acute Toxicity Data. 

Unpublished study prepared by University of Guelph. 76 p. 

44396502 Registrant 

Assessment

Travis, K. (1997) A Modified Tier II Aquatic Exposure Analysis of Cotton 

Pyrethroids, Incorporating Landscape-Level Exposure Factors: Lab Project 

Number: PYRETHROIDS\3. Unpublished study prepared by Zeneca 

Agrochemical (Zeneca Ltd). 221 p. 

44396503 Registrant 

Assessment

Giddings, J. (1997) Aquatic Mesocosm and Field Studies with Cotton 

Pyrethroids: Observed Effects and Their Ecological Significance: Lab Project 

Number: 97-6-7014: 13656.0497.6100.900. Unpublished study prepared by 

Springborn Labs., Inc. 102 p. 

44396504 Registrant 

Assessment

Ritter, A.; Williams, W.; Cheplick, J. (1997) Tier 1 and Tier 2: Modeling of 

Pyrethroid Exposure to Aquatic Nontarget Organisms Associated with Use on 

Cotton: Lab Project Number: WEI 794.01: PWG. Unpublished study prepared 

by Waterborne Environmental, Inc. (WEI). 80 p. 
96

45245501 Registrant 

Assessment

Soderlund, D.; Clark, J.; Mullin, L. et al. (2000) Pyrethroid Insecticides: Is 

there a Common Mechanism of Mammalian Toxicity?: Lab Project Number: 

PWG FQPA 2000-01. Unpublished study prepared by Pyrethroid Working 

Group. 144 p. 

45867701 DER not 

located - not a 

cypermethrin 

study

Smith, E.; Du Preez, L.; Solomon, K. (2003) Field Exposure of Xenopus laevis 

to Atrazine and Other Triazines in South Africa: Exposure Characterization and 

Assessment of Laryngeal and Gonadal Responses: Final Report: Lab Project 

Number: SA-01B: 109-02: C1. Unpublished study prepared by The Institute of 

Environmental and Human Health, Texas Tech University and School of 

Environmental Sciences and Development Potchefstroom, University for CHE. 

91 p. 

45867709 DER not 

located – not a 

cypermethrin 

study

Smith, E.; Du Preez, L.; Solomon, K. (2003) Field Exposure of Xenopus laevis 

to Atrazine and Other Triazines in South Africa: Feasibility Study for Site 

Characterization and Assessment of Laryngeal and Gonadal Responses: Final 

Report: Lab Project Number: SA-01A: 2011-02: C1. Unpublished study 

prepared by The Institute of Environmental and Human Health Texas Tech 

University and School of Environmental Sciences and Development 

Potchefstroom University for CHE. 104 p. 

46051301 Registrant 

Assessment

Ritter, A.; Williams, W. (2003) Tier 2 Modeling of Pyrethroid Compounds 

Exposure to Aquatic Nontarget Organisms Associated with Use on Cotton: 

Final Report. Project Number: WEI/794/03. Unpublished study prepared by 

Waterborne Environmental, Inc. (WEI). 180 p.

47050501 Registrant 

Assessment

Breckenridge, C.; Holden, L. (2007) Evidence for Separate Mechanism of 

Action for Type I and Type II Pyrethroid Insecticides. Project Number: 

PWG/TOX/2007/01. Unpublished study prepared by Pyrethroid Working 

Group. 144 p.

47050502 Open lit Burr, S.; Ray, D. (2004) Structure-Activity and Interaction Effects of 14 

different Pyrethroids on Voltage-Gated Chloride Ion Channels. Toxicological 

Sciences 77(2):341-346.

47506602 DER not 

located

Hall, L.; Killen, W.; Anderson, R. (2008) A Comparison of Sediment Sampling 

Methods for Pyrethroids in Urban/Residential Sediments of California Streams 

and Additional Pyrethroid Sampling in Pleasant Grove Creek Backwater 

Surrogate Sites- Pyrethroid: Assessment. Project Number: T001584/08. 

Unpublished study prepared by Wye Research and Education Center. 62 p.

47506603 DER not 

located

Hall, L.; Killen, W.; Anderson, R.; et. al. (2008) An Assessment of Benthic 

Communities with Concurrent Physical Habitat, Pyrethroid, and Metals 

Analysis in an Urban and Residential Stream in California in 2006 and 2007-

Pyrethroid: Assessment. Project Number: T001523/08. Unpublished study 

prepared by Wye Research and Education Center and Northern Illinois 

University. 229 p.

47543609 Published deNoyelles, F.; Dewey, S.; Huggins, D.; et al. (1994) Aquatic Mesocosms in 

Ecological Effects Testing: Detecting Direct and Indirect Effects of Pesticides. 

P. 577-603 in Ecological Risk Assessment, CRC Press.

47929401 Progress report Giddings, J. (2009) Pyrethroid Working Group Sediment Toxicity Testing 

Program: Progress Report #1: (Hyalella azteca). Project Number: 09713. 

Unpublished study prepared by Compliance Services International. 26 p.

47929402 Overview Giddings, J. (2009) Pyrethroid Working Group Sediment Toxicity Testing

Program: Overview of Part 1 (Comparison of Sediments with Different Organic 

Content): (Hyalella azteca). Project Number: 09718. Unpublished study 
97

prepared by Compliance Services International. 25 p.

47929403 Progress report Giddings, J. (2009) Pyrethroid Working Group Sediment Toxicity Testing 

Program: Progress Report #2: (Hyalella azteca). Project Number: 09744. 

Unpublished study prepared by Compliance Services International. 11 p.

47929404 Registrant 

Assessment

Hall, L.; Killen, W.; Anderson, R.; et al. (2009) An Assessment of the Potential 

Influence of Physical Habitat, Pyrethroids and Metals of Benthic Communities 

in a Residential Stream in California in 2008: (Tubificidae, Paratanytarsus sp., 

Hyalella sp., Physa sp., Dugesia tigrina and Dero digatata): Final Report. 

Project Number: T001605/09. Unpublished study prepared by Compliance 

Services International. 126 p.

47929405 DER not 

located

Hall, L.; Killen, W.; Alden, R. (2007) An Assessment of Benthic Communities 

with Concurrent Physical Habitat, Pyrethroid, Metals and PAH Analysis in an 

Urban and Residential Stream in California: (Seed Shrimp, Snails, 

Chironomids, Oligochaetes and Black Flies). Unpublished study prepared by 

Wye Research and Education Center, and Northern Illinois University. 173 p.

47929406 DER not 

located

Hall, L.; Killen, W.; Anderson, R. (2009) A Comparison of Targeted Sedimemt 

Sampling Methods for Pyrethroids in Urban/Residential Sediments of a 

California Stream in 2008: (Hyalella azteca): Final Report. Project Number: 

T001763/09. Unpublished study prepared by Wye Research and Education 

Center. 56 p.

47944033 Comparison 

summary

Wisk, J. (2010) Comparison of Ecotoxicology Endpoints for AlphaCypermethrin and Cypermethrin. Project Number: 2010/7002965/OCR, 

2010/7002965. Unpublished study prepared by BASF Agricultural Products 

Center. 9 p.

41068006 Open litdifferent 

chemical

Bradbury, S.; Coats, J.; McKim, J. (1985) Differential toxicity and uptake of 

two fenvalerate formulations in fathead minnows (Pimepholes promelas). 

Environmental Toxicology and Chemistry 4:531- 541. 
98

Appendix A. PRD Data Request Justification Tables 

The following proposed Data Call-in tables include rationales for requiring the data requested in 

this problem formulation, explanations of the utility of the data, and explanations for how the 

data might impact risk assessment, following the format provided by PRD.

Guideline Numbers and Study Titles: 

• Test Method 100.4 (OCSPP 850.1770, in prep.); Whole sediment: chronic invertebrates 

freshwater (Hyalella azteca) 

• Test Method 100.5 (OCSPP 850.1760, in prep.); Whole sediment: chronic invertebrates 

freshwater (Chironomus dilutus) US EPA 2001, 

• EPA 600/R-01/020 (OCSPP 850.1780, in prep.); Whole sediment: chronic invertebrates 

marine (Leptocheirus plumulosus)

Rationale for Requiring the Data

No chronic sediment toxicity tests for freshwater or marine invertebrates have been submitted for 

cypermethrin to satisfy the Agency’s updated data requirements for outdoor uses in 40 CFR Part 158 

(October 26, 2007). For cypermethrin, available information indicates that benthic organisms may be 

exposed via run-off or spray drift applications used in agricultural, forest, and residential settings. Based 

on calculations in the most recent EFED assessment, the 21-day sediment porewater EECs predicted for 

cypermethrin ranged from 0.0036 to 0.0253 μg a.i./L (USEPA 2006b). The upper end of this range exceeds 

0.1 of the most sensitive acute LC/EC50 (0.0036 μg a.i./L for amphidpod), which satisfies one of the 

criteria for requiring chronic whole sediment toxicity testing under 40 CFR Part 158. Furthermore, chronic 

reproductive effects were seen in water column studies with aquatic invertebrates (mysid shrimp), with a 

NOAEC = 0.000781 μg a.i./L and LOAEC = 0.00197 μg a.i./L.

PCypermethrin is expected to persist in sediments, based on half-lives in submitted soil metabolism and 

aquatic metabolism studies (aerobic soil ~ 60 days; aerobic aquatic metabolism, 10 days; anaerobic aquatic 

metabolism, 15 days) (MRIDs 42156601, 45920801 and 44876105). These half-life values exceed the 40 

CFR Part 158 criterion of 10 days. 

The third set of trigger criteria for requiring chronic testing (Kd > 50 or log KOW >3 or KOC > 1000) is also 

met for cypermethrin (log KOW is 6.4, the mean KOC value is ~141,700. The physicochemical property 

triggers (Kd, KOW and KOC) reflect the propensity of the chemical to partition onto the particulate or 

organic matter phases of sediments. Exceeding any one of the physicochemical property triggers listed 

above is sufficient for indicating the pesticide has reasonable potential for partitioning to the sediment 

compartment. 

Chronic whole sediment tests on Hyalella azteca, Chironomus tentans, and Leptocheirus plumulosus are 

requested. Although both are freshwater species, Hyalella and Chironomus differ substantially in their 

ecological niche (epibenthic v. infaunal species), physiology, and there is some evidence suggesting 

Hyalella is among the more sensitive invertebrates to pyrethroids based on water column tests (Maund et 

al., 2002; Weston and Jackson, 2009). Pyrethrins have the potential to enter estuarine/marine water bodies 

based on current usage patterns that include coastal areas. Therefore, testing is also needed for an 

estuarine/marine sediment-dwelling invertebrate species. 

Until the final OCSPP guidelines for chronic sediment toxicity tests are published, the registrant should 
99

submit a protocol to EFED for approval prior to test initiation.

• Test Method 100.4: Hyalella azteca 42-d Test for Measuring the Effects of Sediment Associated 

Contaminants on Survival, Growth, and Reproduction in USEPA 2000 Methods for Measuring the 

Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater 

Invertebrates EPA 600/R-99/064 (OCSPP 850.1770, in prep.);

• Test Method 100.5: Life-cycle Test for Measuring the Effects of Sediment-associated 

Contaminants on Chironomus dilutus (formerly known as C. tentans) in USEPA 2000 Methods 

for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with 

Freshwater Invertebrates EPA 600/R-99/064 (OCSPP 850.1760, in prep.); and 

• Leptocheirus plumulosus in USEPA 2001 Method for Assessing the Chronic Toxicity of Marine 

and Estuarine Sediment-associated Contaminants with the Amphipod Leptocheirus plumulosus

EPA 600/R-01/020 (OCSPP 850.1780, in prep.).

Practical Utility of the Data

How will the data be used? 

Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms associated 

with uses of cypermethrin. The data will reduce uncertainties associated with the current risk assessment 

for benthic species and will improve our understanding of the potential effects of cypermethrin.

How could the data impact the Agency’s future decision-making?

Although there was uncertainty in estimating the effect of pyrethrins on benthic organisms in previous 

assessments, there was a potential risk associated with adverse effects identified for other aquatic 

organisms. Acceptable data for benthic organisms will reduce the uncertainty from the previous 

assessment If the data indicates that registered cypermethrin usage may pose a risk of adverse effects to 

non-target benthic organisms above the Agency Level of Concern, the Agency may explore decision 

options to mitigate this risk. The lack of these data will limit the flexibility the Agency and registrants have 

in coming into compliance with the Endangered Species Act, and could result in use restrictions which may 

otherwise be avoided, or which are unnecessarily severe.
100

Appendix B. Reported Cypermethrins Ecological Incident Summaries in the 

EIIS Database

Table B-1. Cypermethrin and Zeta-Cypermethrin Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

I008737-001 Lobster (Decapoda) Probable Registered 

Use

In a 5000 gal. saltwater tank in Cocoa 

Beach, FL 32931, an owner, 

Rancher/Breeder/Farmer found 800 

lobsters dead and another 25 lobsters 

still alive in the tank. He used a 

product (EPA Reg. No. 4822-452): 

RAID Concentrate - Deep Reach 

Fogger in a room adjacent to the tank 

room then closed the tank room door 

for the night, but did not place a towel 

under the door. An air conditioner 

was turned off. He does not have 

UV/ozone sterilization. He has added 

another 200-300 lobsters to this same 

tank and they seem fine. He has 

tested water, ammonia nitrites, nitrate, 

pH and all are within normal limits. 

He could not locate the EPA Reg. No. 

on the container.

I009966-002 Bass (Micropterus spp.)

Bluegill (Lepmis 

macrochirus)

Carp (Cyprinus carpio)

Catfish (Ictaluridae)

Crappie (Centrarchidae)

Minnow (Cyprinidae)

Shad (Clupeidae)

Probable Misuse A fish kill was reported on February 

9, 1998 in Chattanooga, the result of a 

termiticide containing cypermethrin 

entering Rogers Branch and its unnamed tributaries. The Tennessee 

Wildlife Resources Association 

assessed the cost of the dead fish at 

$609.33. Civil penalties and damages 

were assessed, suggesting misuse of 

the pesticide.

Further information was provided by a 

6(a)(2) report from Zenaca Ag 

Products (I006971-001). They claim 

that their investigation indicate that 

the kill was not likely the result of any 

labeled use of Demon TC or of the 

minor spill reported on the property in 

November - December 1997. They 

claim the exposure characteristics 

suggest "introduction of relatively 

massive amounts of chemical directly 

into the water course.

I011346-001 Crayfish (Decapoda) Highly probable Misuse According to a report from the 

Environment Agency - UK, thousands 

of crayfish had been killed in the 

Sherston Avon at Pinkney, upstream 

of Malmesbury, Wiltshire. Within 24 

hours of the first report, the 

Environment Agency's Exeter 

laboratory pinpointed cypermethrin as 

the cause. An investigation led to the 
101

Table B-1. Cypermethrin and Zeta-Cypermethrin Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

Badminton sewage treatment works 

and, ultimately, to a kennel where a 

sheep dip called Crovert (containing 

cypermethrin) had been used to treat 

hounds for mange. After treatment, 

the Crovert was washed off and 

entered the river through the effluent 

of the sewage treatment plant. 

I001031-001 Bluegill (Lepmis 

macrochirus)

Carp (Cyprinus carpio)

Catfish (Ictaluridae)

Largemouth bass 

(Micropterus salmoides)

Highly probable Undetermined This fish kill resulted from the 

application of Demon TC as a termite 

barrier around a home in Henderson, 

Kentucky. Underground drainage tile 

had been installed around the home to 

divert water to a pond 50 feet away, 

and the night following the application 

of Demon there was a heavy rainfall 

which resulted in dumping some of 

the Demon into the pond. 

Approximately 44 fish we re killed.

I018158-017 Koi (Cyprinus carpio) Probable Undetermined Koi allegedly died from a drift 

exposure caused by an Eagle Pest 

Control technician performing a 

routine quarterly perimeter treatment 

using the labeled rate of Probuild TC 

(a.i. cypermethrin). Koi fish pond was

located at the backyard of the 

treatment location.

I017029-001 Unknown fish Highly probable Misuse 

(Accidental)

This is an update of a previous 

incident that occurred in Takoma 

Park, MD, in which a cypermethrinbased pesticide called "Prevail" 

spilled from one of the company's 

pesticide application trucks onto a 

driveway while an employee was 

attempting to repair or replace a 

pump. The employee used a hose to 

wash off the driveway, causing the 

pesticide to drain into a creek and, 

subsequently, into Chesapeake Bay. A 

large number of fish were killed as the 

result of this incident.The pest control 

company was fined $7,300 and its 

license was suspended for 4 years as a 

part of the consent agreement with the 

Maryland Department of Agriculture.

I006971-001 Unknown fish Highly probable Undetermined Zeneca reported that Tennessee Dept. 

of Agriculture was contacted about 

fish kill in several small ponds fed by 

a small stream. State investigators 

estimated 2,200 dead fish (i.e., bass, 

bluegill, shad) were impacted along 

with various other unspecified aquatic 

organisms. Soil and water samples 
102

Table B-1. Cypermethrin and Zeta-Cypermethrin Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

were obtained. Analysis showed trace 

levels of chlorpyrifos and permethrin, 

and exceptionally high levels of 

cypermethrin.

Initial investigation focused on a local 

pest control applicator. A multiagency investigation team later 

focused its attention to alternative 

explanations.

I007107-003 Minnow (Cyprinidae) Highly probable Undetermined This incident is one of the incidents 

stated on a consolidated report 

submitted by the Pesticide 

Investigation Unit, California Dept. of 

Fish and Game for the year 1997. 

One thousand Gambusia (minnows) 

reported dead in Placer County on 2-

7-1997. The PIU confirmed that 

Cypermethrin was the cause of this 

fish kill.

I010444-004 N/R Probable Misuse 

(Accidental)

To comply with 6(a)2 regulations, 

FMC reported an incident that 

occurred in Silver Spring, MD (the 

location was not given in the report 

but was known to this writer). A 

treatment tank was being cleaned out 

by an applicator and the washings 

entered Rock Creek, causing a fish kill 

extending from an area near Walter 

Reed Hospital to the Potomac River. 

Initial estimates that there were 

between 1000 and 150,000 dead fish 

but later, the estimate was revised to 

10,000. The Maryland Dept. of 

Agricuoture found 50 ppb 

cypermethrin in the water.

I013857-011 Unknown fish Probable Misuse 

(Intentional)

To comply with 6(a)2 requirements, 

Syngenta reported that the February 

25, 2003, issue of the Independent 

(London) carried an account of a large 

fish kill in the river Slea, in 

Lincolnshire. According to this 

newspaper, someone had dumped 

Cypermethrin into surface water 

drains at an industrial site, infecting 

13 miles of the river and causing the 

death of 100,000 fish.

I004876-011 Crayfish (Decapoda)

Stonefly (Plecoptera)

Highly probable Misuse 

(Accidental)

This information was sent in response 

to a letter from Gerard Desir, EPA. It 

concerns a fish kill in the Salmon 

River as the result of cypermethrin 

poisoning.

I000011-001 N/R Possible Registered Pond fishkill via alleged underground 
103

Table B-1. Cypermethrin and Zeta-Cypermethrin Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

Use stream under home, after termite 

control.

I015094-001 Unknown fish Possible Registered 

Use

FMC 6(a)(2) incident report stated 

that a contractor applied Prevail 

(cypermethrin) on a horizontal soil 

surface where a concert slab was to be 

poured. Dead fish were found in a 

stream 1/2 to 1 mile from the 

construction site. No analyses were 

given.

I017984-001 Crayfish (Decapoda) Possible Misuse 

(Accidental)

A web site from the UK reports that 

the joint mater of the Duke of 

Beaufort appeared at Avon 

magistrates on 10/20/1998. He 

pleaded guilty to allowing hounds 

treated with cypermethrin, which is 

used to treat mange, to enter the River 

Avon. The pesticide killed around 

10,000 endangered white clawed 

crayfish in the river.

I011348-001 Sparrow (Fringillidae) Unlikely Undetermined A report on the Internet (Third World 

Network) described a massive killing 

of sparrows in a small village in 

Bangladesh as the result of a massive 

use of cypermethrin. In eggplant and 

pointed gourd fields there was a 

spraying of Ustad the night before. 

The sparrows ate insects that had died 

from the spraying and they, in turn, 

died by the thousands. An original 

estimate was that 5000 had died but 

later indications were that the number 

was much higher. Residents were 

shocked by the massive kill of these 

birds and protests were made against 

the use of pesticides.

I021456-001 Bluegill (Lepomis 

macrochirus)

Largemouth bass 

(Micropterus salmoides)

Possible Undetermined Iowa Departmewnt of Natural 

Resources reported an incident on 

dozens of fish kill in a private pond 

surrounded by soybean field on three 

sides and live pasture field to the 

south in Iowa. There was aerial 

spraying of pesticides onto the 

soybean field.

I000340-009 Goat (Bovidae) Possible Undetermined The report implied that an unspecified 

number of goats may have suffered 

illness due to nearby application of 

cypermethrin.

I000103-010 Barred owl (Strix varia)

Mockingbird (Mimus 

polyglottos)

White-throated sparrow 

Unlikely Undetermined According to the investigative report 

11 dead birds were found near a 

private dwelling (9 sparrows, a 

mockingbird, and a barred owl). It 
104

Table B-1. Cypermethrin and Zeta-Cypermethrin Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

(Zonotrichea albicollis) was suspected that the mortality was 

due to toxicosis. Four birds were 

selected for necropsy (1 mockingbird 

and 3 sparrows). The premises had 

been periodically sprayed for termites 

for 8 years, the most recent being 2 

month prior to the event with 

cypermethrin. Earlier treatments had 

been done with lindane. Analysis of 

brain ChE activity gave normal 

results. Residue analysis of 

gizzard/crop contents revealed the 

presence of Heptachlor Epoxide and a 

significant amount of Dieldrin. there 

was an insufficient amount of brain 

tissue left to make a residue analysis 

of the brain for Dieldrin. According 

to the report brain tissue residue of 

1ppm is considered significant but 

body residues are usually many times 

greater than brain residue. The birds 

were observed to undergo convulsions 

just before dying. Crop/gizzard 

content residue analysis revealed 

Dieldrin at 7480 ppb and Hrptachlor 

Epoxide at 710 ppb. There was no 

evidence of organophosphate, 

carbamate, lindane, or cypermethrin 

pesticides.

I000340-006 Dog (Canis familiaris) Possible Undetermined According to the investigative report, 

a dog was dipped and also exposed to 

pyrethroid products. The dog's illness 

was suspected to be due to one of 

these exposures.

I000340-002 Cat (Felix domesticus) Probable Registered 

Use

According to the report A cat was 

exposed to toxic fumes of 

cypermethrin by following applicator 

around as he worked.

I014202-007 Honey Bee (Apis 

millifera)

Possible Registered 

Use

On Aug 9, 2002, a bee keeper reported 

that queenless hives was observed on 

Aug 8, 2002. Yard was inspected 

where there use to be 32 hives, but has 

declined to 26 hives. All 26 hives 

were open and inspected. 8 of the 

hives were queenless or failing. No 

diseases were found, but Varroa mite 

was positive for one hive. An erratic 

or spotty brood pattern was common. 

Pesticide exposure was suspected. 

One hybrid poplar field was identified 

3.5 miles from the yard, and this field 

had not been treated in 2002. An 

alfalfa field 2.75 miles from the yard 
105

Table B-1. Cypermethrin and Zeta-Cypermethrin Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

was identified and it was sprayed with 

zeta-cypermethrin 23 days prior to the 

observation in the bee yard. Samples 

of pollen were taken and analyzed 

with no detection of zetacypermethrin, carbaryl, 1-naphthol 

and carbofuran. The insecticide 

coumaphos was detected. It is used in 

Check Mite Strips used to control 

Varroa mites.

Note: The insecticide used on the 

alfalfa field was identified by the 

name Mustang and the EPA Reg. # 

279-3126 was also given. Mustang is 

a pyrethin pesticide cancelled in 1983. 

The Reg. # identified the product 

Fury and its active ingredient is zetacypermethrin.

I014202-008 Honey Bee (Apis 

millifera)

Unlikely Registered 

Use

A bee keeper reported on Sept 4, 2002 

that there were dead bees in his bee 

yard. It was also stated that on Aug. 

27, 2002, the bee keeper removed 

honey and that the hives were fine. 

The inspector opened and examined 

20 of the twenty hives. Colonies 

appeared to be disease free, except for 

two hives with normal chalkbrood. 

Two hybrid poplar fields, 3,25 and 8 

miles from the bee yard, were 

identified. There were no insecticide 

treatments to these fields in 2002. An 

alfalfa field had been treated with 

zeta-cypermethrin about 50 days 

before symptoms were reported. Bee 

tissue and pollen samples were 

obtained. Analyses of the samples did 

not detect any carbaryl, 1-naphthol or 

carborfuran. Coumaphos was 

detected in both the bee tissue and 

pollen samples. Level were not given. 

Test for Varroa mites was negative.