UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

OFFICE OF PREVENTION,

PESTICIDES AND

TOXIC SUBSTANCES



### MEMORANDUM

SUBJECT: Section 3 New Crop Use Registration of Hydramethylnon on Pineapples in Hawaii

for Control of Bigheaded Ants ( PC Code Number: 118401, DP Barcode:

D249596 )

TO: Richard Keigwin, Branch Chief
Richard Gebken, PM Team Reviewer Registration Division (7505C)

FROM: Santhini Ramasamy, Environmental Scientist Lewis Ross Brown, III, Biologist Pat Jennings, RAPL
Sid Abel, Branch Chief
Environmental Fate and Effects Division (7507C)

# Hydramethylnon

PC Code: 118401

## Table of Contents

I. ENVIRONMENTAL RISK CONCLUSIONS

................................ ................................ 3

II. INTRODUCTION

................................ ................................ ................................ ....... 4

III. INTEGRATED ENVIRONMENTAL RISK CHARACTERIZATION

............................ 6

IV. ENVIRONMENTAL FATE AND TRANSPORT ASSESSMENT

............................... 9

V. DRINKING WATER ASSESSMENT.

................................ ................................ .... 10

VI. AQUATIC EXPOSURE AND RISK ASSESSMENT

................................ ............... 13

VII. TERRESTRIAL EXPOSURE AND RISK ASSESSMENT

................................ ..... 15

APPENDIX I: Summary of Environmental Fate and Transport Properties

.................. 18

APPENDIX II : Drinking Water and Aquatic Exposure Model Outputs

........................ 24

APPENDIX III: Ecotoxicity Studies

................................ ................................ .............. 26

APPENDIX IV: Risk Assessment

................................ ................................ ................ 32

APPENDIX V: Data Requirements

................................ ................................ .............. 34

### 3 I. ENVIRONMENTAL RISK CONCLUSIONS

Although several studies are lacking, based on the available data EFED concludes the following concerning the potential environmental risk from the use of hydramethylnon:

Hydramethylnon is an organic trifluoromethyl aminohydrazone insecticide used in baits to control
fire ants, leafc utter ants, and cockroaches in both indoor and outdoor applications. Using the proposed application rate on the label of 3.0 lbs a.i./A in granular formulation, hydramethylnon may pose acute risk to terrestrial organisms. The estimated risk quotients for the proposed pineapple uses of hydramethylnon for 20

- g body weight small birds exceeded the levels of concern for acute, acute restricted use and endangered species risk presumption categories (RQ = 0.85). Acute risk quotients were below levels of concer n for 180

- g and 1000

- g birds exposed to hydramethylnon. Acute levels of concern were exceeded at the acute risk, endangered species, and restricted use risk presumption categories for small to medium, 15

- 35 g, mammals (15

- g mammals RQ = 2.54 and 35

- g mam mals RQ = 1.09). No acute levels of concern were exceeded

for 1000

- g mammals exposed to hydramethylnon. Chronic risk quotients for birds and mammals at all of the above body weights were not determined because there is presently no

standard method for e stimating chronic risk to terrestrial organisms for granular

- type

formulations.

In the absence of acute toxicity endpoints for terrestrial and semiaquatic plants, a quantitative assessment of acute risks was not possible. Based on proposed maximum label application rates and GENEEC 2.0 modeling, acute levels of concern for freshwater fish were exceeded for the acute restricted use and endangered species risk presumption categories (RQ = 0.11

- 0.18). No

acute levels of concern were exceeded for freshwater invertebrates. Due to an absence of data on acute toxicity endpoints, estimating risk to estuarine/marine organisms (fish and invertebrates) from exposure to hydramethylnon was not possible. Based on the potential location and pattern of hydramethylnon use on pineapples these data are required and are listed as data gaps.

Based on hydramethylnon’s relative persistence and immobility in the environment, the major route of dissipation appears to be photodegradation, with a half

- life of about 1 hr in aqueo us systems and 21 to 25 days in soil. Because hydramethylnon is very strongly sorbed by soil particles (i.e., K d 

### = 1039

- 1725), it is practically immobile in most soils. At the soil surface, there is the potential for photodegradation of hydramethylnon. Due to limited sunlight below soil surfaces, the bound residues of hydramethylnon would not be susceptible to photodegradation. Based on laboratory aerobic and anaerobic soil metabolism studies, hydramethylnon is very persistent, with a half

- life of more than a year for each process. Contamination of surface water is possible by movement of soil particles bound to hydramethylnon after rainfall events. Contamination of surface water from drift is negligible since the proposed use product for pineapples is granular. Based on strong binding to soil and low leaching potential (i.e., no

residues recovered below 0

- 6 inches below the soil surface), it is unlikely that hydramethylnon would contaminate groundwater. It appears that hydramethylnon has a strong tend ency to bioaccumulate and depuration is very slow.

Based on a search of the National Water

- Quality Assessment (NAWQA) Program, no monitoring

### 4 data were found for hydramethylnon. Based on Tier

- 1 modeling (i.e., FIRST), the acute concentrations are not likely to exceed a peak concentration of 76.09 ppb whic h is recommended for estimating acute risks from exposure of humans to hydramethylnon in drinking water from surface water sources. The predicted annual daily average concentration is not likely to exceed 1.45 ppb which is recommended for estimating chron ic risks from exposure of humans to hydramethylnon in drinking water from surface water sources. Hydramethylnon does not appear to substantially leach into soils, based on its high affinity to bind to soil (i.e., K d 

### = 1039

- 1725).

Based on SCI

- GROW modeli ng, the estimated concentrations in ground water for the proposed pineapple uses are not likely to exceed 0.035 ppb

. This concentration is appropriate for estimating the potential for acute and chronic risks from exposure of humans to hydramethylnon in drinking water from ground water sources.

II. INTRODUCTION

Hydramethylnon is an organic trifluoromethyl aminohydrazo ne insecticide belonging to a chemical class of compounds known specifically as trifluoromethyl aminohydrazone compounds. Its mode of action is that of an electron transport inhibitor.

Physical and Chemical Properties

Common Name: Hydramethylnon

Chemical Name : Tetrahydro

- 5,5

- dimethyl

- 2(1H)

- pyrimidinone[3

- [4

- (trifluoromethyl)phenyl]

- 1

- [2

- [4

- t rifluoromethyl)phenyl]ethenyl]

- 2

- propenylidene]hydrazone Chemical Family : amidinohydrazone Empirical Formula : C 25 

### H 24 

### F 6 

### N 4 

### Trade and Other Names : Amdro

, Combat

, Maxforce

, Sensible

, Siege Molecular Weight : 494.50 CAS Registry No. : 67485

- 29

- 4

P.C. Code : 118401 Physical Appearance: Yellow to tan crystalline solid Solubility in Water 1 

### : 0.88 ppm Melting Point : 189

- 191 **°** C
Vapor Pressure 1 

### : 6 x 10 - 8 

### mm of Hg at 25 **°** C Henry’s Law Constant : 2.6x10 - 7 

### atm.m 3 

### /mol (Calculated) Octanol/Water Partition Coefficient (Kow) 1 

### : 27,965 at 25 **°** C (Log Kow = 4.45 )

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

1 MRID 41612502

### 5 Structure :

Approach to Risk Assessment

Hydramethylnon is proposed to be used on pineapples at a maximum rate per application of 3.0 lbs a.i./A. The proposed maximum annual application rate is 6.0 lbs a.i./A. The proposed frequency of application is not listed on the label. Based on the propo sed maximum annual rate and maximum rate per event, 2 applications per year were assumed. As proposed in the label, the application interval of 4 months is used in the exposure modeling. However, it is not clear whether it refers to minimum or maximum i nterval between applications.

Toxicity testing reported in this document does not represent all species of bird, mammal, or aquatic organisms. Only two surrogate species for both freshwater fish and birds are used to represent all freshwater fish (2000+) and bird (680+) species in the United States. For mammals, acute toxicity studies are usually limited to laboratory rats and mice. Neither reptiles nor amphibians are tes ted. In assessing risk and/or hazard, it is assumed that avian and reptilian toxicities are similar. Also, hazard and risk are assumed to be similar for fish and amphibians. Generally, the most toxic endpoints for the technical grade active ingredient (TGA I) are used in the assessment to represent each group of aquatic and terrestrial organisms.

The EECs used for determining terrestrial risk quotients were derived using granular EEC calculations. The following formula was used to predict the granular EEC for birds and mammals at three different body weights (i.e., birds: 20 g, 180 g, 1000 g; mammals: 15 g, 35 g, and 1000 g):

EEC lbs/ft 2 

### = application rate (lbs a.i./A)* (453,590 mg/lbs/43,560 ft 2 

### /A)

RQ = application rate (lbs a.i./A)*(453,590 mg/ lbs/43,560 ft 2 

### /A)

LD 50 

### mg/kg *BW (g)/(1000 g/Kg)

### 6 The EECs used for modeling acute and chronic aquatic exposures were determined through GENEEC 2.0 modeling. GENEEC 2.0 uses basic environmental fate data and pesticide

label application information to estimate the EECs in a one

- hectare, two

- meter deep pond adjacent to10 hectares of treated field.

III. INTEGRATED ENVIRONMENTAL RISK CHARACTERIZATION

Hydramethylnon is an insecticide and belongs to a class of chemical compound s known as trifluoromethyl aminohydrazone compounds. Hydramethylnon may pose acute risks to terrestrial organisms should the compound enter into terrestrial habitats. Intake of hydramethylnon residues from food items is the only route of exposure conside red in this risk assessment. Risk quotients for 20

- g birds and 15

- to 35

- g mammals exceed acute risk, restricted use, and endangered species risk presumption categories (see Appendix IV for details).

A search in the endangered species database (Danger 97 ) identified the following perching birds in two counties in Hawaii, with body weight around 20g , for which RQs exceeded levels of concern: Hawaii `akepa, `Akia pola`au, Palila, `O`u (Honey Creeper), `Akia loa, Nuku pu`u (Kauai), Kauai
`O`o, small Kauai t hrush, large Kauai thrush (Table 1). Based on consultation with Larry Turner of the Field and External Affairs Division (FEAD) of the Office of Pesticide Programs (OPP) of EPA, these song birds are not at risk from hydramethylnon uses on pineapples becaus e many of these small birds inhabit elevated forests instead of lower tropical forests where pineapples are usually grown. Even the ground

- dwelling birds (e.g., small Kauai thrush) live only in the dense, wet forests of Alkai swamp at 4000 feet on Kauai. Also, many of these species are extremely rare. For example, Akia loa was last seen in 1965 and is thought to be extinct (World Wildlife Fund Guide to Endangered Species, 1990). Therefore, the potential endangered risk posed by hydramethylnon uses on pi neapples to small birds is minimal. Table 1 lists other endangered birds identified in two counties in Hawaii using the Danger 97 database. Since the other endangered birds are either duck

- like birds (i.e., Hawaiian goose, Hawaiian duck) or sea birds (i.e

., Hawaiian dark

- rumped petrel and Hawaiian stilt) and are well above 20

- g body weight and RQs did not exceed levels of concern for acute endangered species for larger birds, these birds are not expected to be impacted by hydramethylnon uses.

Among the ma mmals up to 30

- g body weight, the Hawaiian Hoary bat was the only endangered species identified in Hawaii and Kauai counties. Based on consultation with Larry Turner, the bats are not believed to be at risk from hydramethylnon uses on pineapples as the ba ts mainly eat flying insects which are not expected to be exposed as a result of application of hydramethylnon. Although the listed endangered birds and mammals are not at risk for hydramethylnon uses on pineapples in Hawaii, the estimation of risk to end angered species would be revisited for other uses proposed in the future.

### 7 Table 1: List of Endangered Avian Species Identified in Hawaii for Pineapple Uses

Species Scientific Name County(ies)

Hawaii `Akepa Loxops coccineus coccineus Hawaii

Akia Pola`au Hemignathus munroi Hawaii

Hawaiian Coot (Alae keo keo) Fulica americana alai Hawaii, Kauai

Hawaii Creeper Oreomystis mana Hawaii

Hawaiian Crow (`Alala) Corvus hawaiiensis Hawaii

Hawaiian Duck (Koloa) Anas wyvilliana Hawaii, Kauai

Hawaiian Goose Nesochen sandvicensis Hawaii, Kauai

Hawaiian Hawk (Io) Buteo solitarius Hawaii

`O`u (Honey Creeper) Psittirostra psittacea Hawaii, Kauai

Palila Loxioides (=Psittirostra) bailleui Hawaii

Hawaiian Dark

- rumped petrel Pterodroma phaeopygia sandwichensis Hawaii, Kauai

Newell’s Townsend’s Shearwater Puffinus auricularis newelii Hawaii, Kauai

Hawaiian Stilt Himantopus himantopus knudseni Hawaii, Kauai

`Akia Loa Hemignathus proceruhemignathus

procerus Kauai

Hawaiian Common Moorhen Gallinula chloropus sandvicensis Kauai

Nuku pu`u (Kauai) Hemignathus lucidus Kauai

Kauai `O`o Moho braccatus Kauai

Large Kauai Thrush Myadestes myadestinus Kauai

Small Kauai Thrush Myadestes palmeri Kauai



### Although the results of this risk assessment indicate that hydramethylnon is not expected to pose
acute risks to freshwater fish and invertebrates, levels of concern for freshwater fish for acute restricted use and acute endangered species risk presumptio n categories are exceeded (i.e., RQ =

0.11

- 0.18). A search of the endangered species database, Danger 97, did not identify any endangered freshwater fish in ponds near the expected use area, so exposure and acute risk to endangered freshwater fish is not expected. Since no chronic ecotoxicity studies for freshwater organisms were submitted, chronic toxicity endpoints have not been determined. Therefore, potential chronic risks to freshwater organisms (i.e., fish and invertebrates) from proposed hydrameth ylnon uses are unknown. Since no acute or chronic ecotoxicity studies were submitted for estuarine/marine organisms (i.e., fish and invertebrates), acute and chronic toxicity endpoints for estuarine/marine organisms have not been determined. Therefore, p otential acute and chronic risks to these organisms from proposed

### 8 hydramethylnon uses are unknown. Based on strong soil binding affinity of hydramethylnon and relatively fast photolytic degradation, it appears unlikely that surface water concentrat ions will be contaminated significantly from the proposed uses of hydramethylnon. However, under limited sunlight conditions, the high annual application rate of 6.0 lbs a.i./A may contaminate surface water with residues of hydramethylnon. It is expected that hydramethylnon reaches the surface water bound to soil particles due to strong soil binding properties. From the lab soil metabolism studies, hydramethylnon is considered to be persistent (half

- life more than a year) in the environment. However, und er field conditions, hydramethylnon appeared to dissipate at a faster rate with a half

- life of 3 to 55 days. There is a difference of 1 to 2 orders of magnitude in half

- lives between the laboratory soil metabolism study and the terrestrial field dissipati on study. The laboratory half

- life which is longer than the field

half

- life was used to estimate drinking and aquatic exposures. Environmental and drinking water

concentrations would be lower if the actual half

- life of hydramethylnon is closer to that

de termined from the terrestrial field dissipation study.

It should be noted that the predicted EECs from Tier I models

- (FIRST, GENEEC and SCIGROW) are not refined as they are mainly influenced by annual application rate and application method

and do not account for location

- specific hydrogeologic and climatic characteristics. Concentrations in the environment may be lower or higher than the Tier I predicted EECs depending upon the use scenarios and weather conditions.

SCI

- GROW was developed using K

oc 

### values ranging from 32

- 180 L/Kg. Given the high Koc for hydramethylnon (median Koc 205,570), there is uncertainty in the estimated ground water levels due to extrapolation beyond the range of Koc values used to develop the standard regression. It is

poss ible that the volcanic Hawaii regions where the pineapples are grown are susceptible to ground water contamination due to the porous nature of the soil. Therefore, the ground water concentrations are still modeled using SCI

- GROW. If concerns are raised

b y exposures of less than 0.0345 ppb, a prospective ground

- water study would be

recommended.

Environmental fate data are sufficient for predicting the parent concentrations in drinking water. However, the fate studies are insufficient to identify and char acterize degradates. Since hydramethylnon is relatively stable in soil metabolism studies, it is expected that photolytic degradation is the major route of dissipation under field conditions (21 to 25 days in the field versus more than 1 year in the labor atory). Although there is fast dissipation in the field studies, there is insufficient information on the potential photolytic degradates in the fate studies. Specifically, the two field studies for hydramethylnon do not include any information on the two major photo transformation products, 4H

- pyrimido
[2

- 1,c]as

- triazio

- 4

- one

- 1,6,7,8

- tetrahydro

- 7,7

- dimethyl

- 3

- [p

- (trifluoromethyl)

- styryl] and 1,5

- bis (alpha, alpha, alpha

- tri

- fluoro

- p

- tolyl)

- 1,4

- pentadien

- 3

- one. Further, the lab aquatic photolysis study di d not identify and characterize the two unknown major metabolites (Unknown 3 and 4). Finally, there are limited data on the mobility of hydramethylnon degradation products at this time.

### 9 Based on the available data, EFED is unable to ascertain the potential contamination of surface and ground water sources with hydramethylnon degradates. If degradates were determined to be of toxicological concern, it is recommended that additional inform ation needs to be submitted for any future uses of hydramethylnon.

IV. ENVIRONMENTAL FATE AND TRANSPORT ASSESSMENT

Summary

Hydramethylnon is relatively persistent and non

- mobile in the environment. The major route of dissipation for hydramethylnon ap pears to be photodegradation. Although the laboratory soil metabolism studies indicate that the compound is stable in the aerobic and anaerobic conditions, hydramethylnon degraded relatively fast in the field studies conducted in Florida and Texas. The

r apid degradation in the field could not be adequately explained due to photodegradation alone, unless there is an offsite movement of pesticides. It is possible the granular product is moved from the field by ants or other species that mistake granules fo r food sources. Additional information is needed from the registrant to explain the discrepancy between the laboratory and field studies with regard to persistence of the chemical. Due to the high soil binding affinity (Kd

= 1039

- 1725), the chemical is l ikely to partition into the soil and sediments. Hydramethylnon has a tendency to bioaccumulate and the depuration is slow.

Environmental Fate Assessment

Hydramethylnon is moderately persistent and is classified as immobile according to McCall’s

classi fication scheme (1980). Based on laboratory studies, hydramethylnon is stable to hydrolysis with a half

- life greater than 30 days and stable to soil metabolism under aerobic and
anaerobic conditions, with a half

- life longer than one year for each. On soi l surfaces under ample sunlight conditions, hydramethylnon could be photolysed rapidly and could be less persistent. The laboratory aqueous photolysis half

- life is less than one hour and soil photolysis half

- life ranges from 21to 25 days under continuous irradiation conditions. The aqueous photolysis study identified certain major degradates: a photodegradate, 4H

- pyrimido
[2

- 1,c]as

- triazio

- 4

- one

- 1,6,7,8

- tetrahydro

- 7,7

- dimethyl

- 3

- [p

- (trifluoromethyl)

- styryl], representing 25.2 to 30.5% of the radioactivity and a second degradate, 1,5

- bis(alpha, alpha, alpha

- trifluoro

- p

- tolyl)

- 1,4

- pentadien

- 3

- one, representing 28.0% of the radioactivity. In addition, two other major degradates were noted but were not identified or characterized (i.e., Unknown 3

and Unknown 4 ). Degradates were also observed in the soil photolysis study ( hydramethylnon epoxide and ketone compounds ) but these degradates were not considered major degradates.

Hydramethylnon adsorbs strongly to most of the soils from loamy sand to silty loam (Kd =

1039

- 1725). The calculated Koc values were: 358276 (loamy sand), 287759 (sandy loam), 123381 (loam), and 95389 (silt loam). These high Koc values indicate hydramethylnon is very

immobile in most soils in the environment. Under field conditi ons, in Texas and Florida, hydramethylnon appears less persistent with reported half

- lives of 3 to 55 days. No degradate information was reported in the field studies. Hydramethylnon showed some tendency to accumulate in fish tissues with reported biocon centration factors of 1300X in whole fish, 780X in

### 10 fillet, and 1900X in viscera. Depuration was slow with 48 to 63% of residues decreased after a

14

- day clearance period.

The detailed fate summary and the structures of hydramethylnon and degradates can b e found in Appendix I.

V. DRINKING WATER ASSESSMENT

The laboratory studies submitted are fairly complete for modeling the parent compound for the drinking water assessment. Based on a search of the National Water

- Quality Assessment (NAWQA) Program database, no monitoring data were found for hydramethylnon. No Maximum Contamination Limit (MCL) or Health Advisory (HA) has been established for hydramethylnon residues in drinking water. Based on the available information in the

fate studies and on the toxicity of potential degradates, MARC (Metabolism Assessment Review Committee) recommended to examine parent, but not degradates for assessing drinking water exposures.

Surface Water

Contamination of surface water is possible by runoff of hydramethylno n bound to soil particles after rain events. Contamination from drift is negligible since the formulation for the proposed pineapple uses is granular. The Tier I model, FIRST (FQPA Index Reservoir Screening Tool, version 1.0, Aug 1, 2001) was used to esti mate drinking water concentrations of hydramethylnon in surface water from a drinking water reservoir adjacent to a field to which pesticide has been applied. This model assumes the transport of pesticides from a 172.8

- hectare field adjacent to a 5.3

- hect are, 2.74

- meter deep drinking water reservoir. In addition to fate and mobility characteristics of the pesticide, this model assumes reductions in the water concentrations of hydramethylnon due to the percentage of the watershed which is cropped (i.e., PC A, percent cropped area). There is no assigned PCA for pineapple uses, and therefore, the default value of 0.87 is used. This model predicts the peak and annual daily average concentrations of the pesticide in drinking water from surface water sources. The peak concentration is used to estimate acute risks from exposure of humans to hydramethylnon in drinking water from surface water sources. The annual daily average concentration is used to estimate chronic risks from exposure of humans to hydramethyln on in drinking water from

surface water sources.

The input parameters for FIRST modeling are provided in the Table 2.

Table 2. FIRST Input Parameters

Model Input Parameter Input Value Source

Chemical Name Hydramethylnon AMDRO label (EPA Reg

No: 241

- 322)

AMDRO label (EPA Reg

### 11 Table 2. FIRST Input Parameters

Crop Name Pineapples No: 241

- 322)

Application Rate 3.0 lbs a.i./A AMDRO label (EPA Reg

No: 241

- 322)

Maximum. Number of Applications per Season 2 * AMDRO label (EPA Reg

No: 241

- 322)

Interval Between Applications 120 days AMDRO label (EPA Reg

No: 241

- 322)

Percent Crop Area (PCA) 0.87 (default value) FIRST Users Manual (August 1, 2001)

Kd 1669 ( Lowest non

- sand value ) MRID No. 41888302

Aerobic Soil Metabolism t 1/2 = 407.6 days ( 90 th upper percentile of the mean for the following half

- lives: 375, 391 days ) MRID No. 42320801

Pesticide Wetted

- in No AMDRO label (EPA Reg

No: 241

- 322)

Method of Application/Type of Droplet Size Aerial, coarse granules AMDRO label (EPA Reg

No: 241

- 322)

Incorporation Depth 0.0 in AMDRO label (EPA Reg

No: 241

- 322)

Water Solubility 0.88 ppm Product Chemistry (MRID No. 41612502 )

Aerobic Aquatic Metabolism t 1/2 = 815.2 days (2 x 407.6 days) Twice the aerobic soil metabolism input value

Hydrolysis t 1/2 = stable MRID No. 42194701

Aqueous Photolysis t 1/2 = 0.04 day MRID Nos. 42238201 and

42473301

* The proposed frequency of application is not explicit on the label. Derived based on the proposed maximum annual rate of 6.0 lbs a.i./A
and maximum rate per event of 3.0 lbs a.i./A.



### Based on Tier

- 1 modeling (i.e., FIRST), the acute concentrations are not likely to exceed a peak concentration of 76.09 ppb which is recommended for estimating acute ri sks from exposure of humans to hydramethylnon in drinking water from surface water sources. The predicted annual daily average concentration is not likely to exceed 1.45 ppb which is recommended for estimating chronic risks from exposure of humans to hydr amethylnon in drinking water from surface water sources. The output from FIRST modeling is presented in the Appendix II. Currently, EFED does not have a scenario for pineapple

### 12 uses to proceed with Tier 2 modeling. Should there be any drinking water con cerns with Tier I modeling values, monitoring studies must be considered.

Ground Water

Ground water contamination is expected to be low due to high binding affinity of hydramethylnon to the soil. For any potential ground water contamination from the

p roposed use of hydramethylnon on pineapples, SCI

- GROW (version 2.2, Nov 1, 2001) modeling was performed. The model estimates the upper bound ground water concentrations of pesticides likely to occur when the pesticide is used at the maximum

allowable rate in areas where ground water table is shallow particularly vulnerable to

contamination. The SCI

- GROW model is based on the fate properties of the pesticide, the application rate, and the number of applications. The input parameters are provided

in Table 3. The estimated concentration in ground water for the proposed pineapple uses is 0.035 ppb . This value is appropriate for estimating acute and chronic risks for the human health dietary risk assessment. The actual output from SCI

- GROW is presented in Appendix II.

Table 3. SCI

- GROW Input Parameters

MODEL INPUT VARIABLE INPUT VALUE SOURCE

Chemical Name Hydramethylnon AMDRO label (EPA Reg No: 241

- 322)

Aerobic Soil Metabolism t 1/2 = 383 ( Median Value for the following half

- lives: 375, 391 days ) MRID No. 42320801

K

oc 205570 (Median for the following Koc
values : 358276, 287759, 123381, 95389) MRID No. 41888302

Application Rate 3.0 lbs a.i./A AMDRO label

Max. Number of Applications/Year 2 AMDRO label



### SCI

- GROW was developed using K oc 

### values ranging from 32

- 180 L/Kg. Since Koc values for hydramethylnon (Koc 205570) are outside the range of values for which

SCI

- GROW was developed, there is uncertainty in the estimation of ground water concentrations. It is possible that the volcanic Hawaii regions where the pineapples are grown are susceptible to ground water contamination due to the porous nature of the soil. Therefore, the ground water concentrations are still modeled using SCI

- GROW. If concerns are raised by exposures of less than 0.0345 ppb, a prospective ground

- water study would be recommended.

### 13 VI. AQUATIC EXPOSURE AND RISK ASSESSMENT

Based on ecological effects data, the aquatic toxicity endpoints used in the current assessment can

be characterized as follows:

 Very highly to moderately toxic in freshwater fish (rainbow trout, LC 50 

### = 150 ppb; channel
catfish, LC 50 

### = 90 ppb; bluegill sunfish, LC 50 

### =1700 ppb)

 Moderately toxic to freshwater invertebrates (water flea LC 50 

### =1140 ppb ).

 Data sup porting the chronic reproductive effects of hydramethylnon to freshwater fish using the fathead minnow as the test species were not available for use in this risk assessment. Therefore, the chronic reproductive effects hydramethylnon may pose to

freshwat er fish are not known at this time.

 Data supporting the chronic reproductive effects to freshwater invertebrates using the Daphnia magna, water

- flea, as the test species were not available for use in this assessment. Therefore, the chronic reproductive e ffects hydramethylnon may pose to

freshwater invertebrates are not known at this time.

 Data supporting the acute ecotoxicity effects hydramethylnon may pose to

estuarine/marine fish and invertebrates were not available for use in this assessment.

Therefo re, the acute ecotoxicological effects hydramethylnon may pose to

estuarine/marine fishes and invertebrates are unknown at this time.

 Data supporting the chronic ecotoxicity effects hydramethylnon may pose to

estuarine/marine fishes and invertebrates were not available for use in this assessment. Thus, the chronic ecotoxicological effects hydramethylnon may pose to estuarine/marine

fishes and invertebrates can not be determined at this time.

Details of the aquatic toxicological studies are presented in Ap pendix III. The Agency’s LOCs for aquatic organisms are presented in Appendix 1V.

Aquatic Exposure

The EECs needed for determining the acute and chronic risk quotients for aquatic organisms are modeled using GENEEC 2.0 (version 2.0, Aug 1, 2001). GEN EEC 2.0 uses basic environmental fate data and application information from the pesticide label to estimate EECs in a one

- hectare,

two

- meter deep pond adjacent to10 hectares of treated field. The environmental fate parameters

used in the model are the sam e as those used for FIRST modeling. Unlike FIRST, the percent cropped area is not accounted for in the GENEEC 2.0 model. For details on input parameters for the GENEEC 2.0 model, refer to the input parameters in Table 2.

### 14 The proposed label for p ineapple uses recommends a maximum rate per application of 3.0 lbs ai/A with no more than 6.0 lbs a.i./A per year, indicating two applications for the whole year. Since the application interval was not indicated on the label, a 30

- day minimum preharvest i nterval specified on the label was assumed to be the interval between applications. The estimated surface water concentrations to which aquatic life are exposed are presented in Table 4. The peak exposure concentrations are used for estimating the acute risk for fish, aquatic invertebrates and aquatic plants.

Table 4

- GENEEC 2.0 Modeling

Peak (ppb) 21

- day Average (ppb) 60

- day Average (ppb) 90

- day Average (ppb)

15.9 2.85 1.00 0.67



### Freshwater Fish

Acute risk quotients for freshwater fish are presented in Table 5. Using the proposed application rate of 3.0 lbs a.i./A applied in granular formulation, levels of concern were exceeded for the endangered freshwater fish when the end points for rainbow trout (RQ = 0.11) and channel catfish were used (RQ = 0.18). The results indicate that the acute risk posed to freshwater non

- endangered fish from granular use of hydramethylnon on pineapples in Hawaii is expected to be minimal.

Table 5

- - Freshwater Fish Acute Risk Quotients Using Hydramethylnon

Species Toxicity Value (ppb) Peak EEC (ppb) 60

- Day Average

EEC (ppb) Acute

Risk Quotient Chronic

Risk Quotient

Rainbow trout (Oncorhynchus mykiss ) 150 15.9 1.0 0.11 N/A

Bluegill sunfish ( Lepomis

macrochirus ) 1700 15.9 1.0 <<0.01 N/A

Channel catfish (Ictalurus
punctatus ) 90 15.9 1.0 0.18 N/A



### Chronic levels of concern were not quantified for freshwater fish due to a lack of available

data for the Early

- Life Stage using the fathead minnow. Without an endpoint value the chronic risk hydramethylnon may pose to freshwater fish cannot be determined.

### 15 Freshwater Invertebrates

Acute risk quotients for freshwater invertebrates are presented in Table 6. Based on proposed maximum application rates on the label, levels of concern were not exceeded for freshwater invertebrates exposed to the granular formulation of hydramethylnon.

Table 6

- Freshwater Invertebrate Acute Risk Quotients Using Hydram ethylnon

Species Toxicity Value (ppb) Peak EEC (ppb) 21

- Day Average

EEC (ppb) Acute

Risk Quotient Chronic

Risk Quotient

Daphnia magna

(waterflea) 1140 15.9 2.82 0.01 N/A



### Estuarine/Marine Organisms

Acute and chronic risks to estuarine/marine fish and invertebrates cannot be quantified at this time due to a lack of appropriate ecotoxicological endpoints.

Exposure and Risk to Plants

Acute risks to terrestrial and semi

- aquatic plants cannot be quanti fied at this time due to a lack of appropriate ecotoxicity endpoints.

Aquatic Ecological Incident Data

No aquatic ecological incidents for hydramethylnon were identified in EFED’s Ecological

Incident database.

VII. TERRESTRIAL EXPOSURE AND RISK ASSESSMENT

Based on ecological effects data, the toxicity endpoints used in the current terrestrial assessment

can be characterized as follows:

 Slightly toxic to practically non

- toxic on an oral acute toxicity basis (Northern Bobwhite Quail, LD 50 

### =1828 mg /kg; Mallard Duck, LD 50 

### =2510 mg/kg)

 Slightly toxic on a subacute oral basis (Northern Bobwhite Quail, LC 50 

### =1136 ppm; Mallard Duck, LC 50 

### =4355 ppm)

 Chronic reproductive effects observed in mallard duck (NOAEC=28.5 ppm, based on weight of 14

- day old survivo rs)

 Slightly toxic to small mammals on an acute basis ( LD 50 

### = 817 for males and

LD 50 

### =1502 for females)

### 16  Chronic reproductive effects in smalls mammals (Norway rat NOAEL=50 ppm

, male infertility was noted at 100 ppm ).

 Practically non

- toxic to non

- t argeted terrestrial insects (Honeybee LD 50 

### =68

μ g/bee).

Details of the avian and mammalian toxicological studies are presented in Appendix III

. The Agency’s LOCs for risk presumption categories for terrestrial organisms are presented in Appendix 1V.

Avian Acute and Chronic Risk

Avian acute risk quotients for hydramethylnon granular broadcast applications were determined using the following formula:

RQ = Application rate(lbs/acre) *(453590 mg/lbs/43560 ft 2 

### /acre)

LD 50 

### mg/kg BW/day*Weight of bird (g)/1000 g/Kg

Acute risk quotients for 20, 180, and 1000 g birds are shown in Table 7.

Table 7

- Acute Risk Quotients For Avian Organisms Following Broadcast Granular Applications Of Hydramethylnon

Body Weight (kg) LD 50 (mg/kg) 1 mg ai/ft 2 Acute RQ 2

(LD 50 /ft 2 ) Risk Presumption Categories

Exceeded

0.020 36.6 31.24 0.85 Acute, Restricted Use, and Endangered Species

0.180 329.04 31.24 0.09 None

1.0 1828 31.24 0.01 None

1. LD

50 per animal = LD

50 mg/kg BW/day*Weight of animal (g)/1000 g/Kg

2. RQ= Application rate(lbs/acre) *(453590 mg/lbs/43560 ft2/acre)

LD

50 mg/kg BW/day*Weight of animal (g)/1000 g/Kg



### Based on estimated risk quotient of 0.85, acute levels of concern were excee ded for acute risk, restricted use, and endangered species risk presumption categories for 20

- g birds exposed to granular broadcast applications of hydramethylnon on pineapples.

Acute risk levels of concern were not exceeded for 180

- 1000 g birds exposed t o granular broadcast applications.

At present, EFED has no method to estimate chronic risk to birds exposed to granular

formulations.

### 17 Mammalian Acute and Chronic Risk

For small mammals, acute risk quotients were calculated using the following f ormula:

RQ = Application rate(lbs/acre) *(453590 mg/lbs/43560 ft 2 /acre)

LD 50 mg/kg BW/day*Weight of animal (g)/1000 g/Kg



### Acute risk quotients for smalls mammals are tabulated in Table 8.

Table 8

- Acute Risk Quotients For Mammals Exposed to Broadcast Granular Applications of Hydramethylnon

Body Weight (kg) LD 50 (mg/mammal) 1 mg ai/ft 2 Acute RQ 2

(LD 50 /ft 2 Risk Presumption Categories Exceeded

Small mammal

0.015 12.3 31.24 2.54 Acute, Restricted Use, and Endangered Species

Medium mammal

0.035 28.6 31.24 1.09 Acute, Restricted Use, and Endangered Species

Large mammal

1.0 817 31.24 0.04 None

1. LD

50 per animal = LD

50 mg/kg BW/day*Weight of animal (g)/1000 g/Kg

2. RQ= Application rate(lbs/acre) *(453590 mg/lbs/43560 ft2/acre)

LD

50 mg/kg BW/day*Weight of animal (g)/1000 g/Kg



### Levels of concern were exceeded for 15 to 35 g mammals exposed to broadcast granular applications of hydramethylnon at the maximum application rate proposed on the l abel for acute risk, acute restricted use, and acute endangered species risk presumption categories. The risk quotient for 15

- g mammals was determined to be 2.54 while that for

35

- g mammals was determined to be 1.09. No acute levels of concern were exceed ed

for 1000

- g mammals.

At present, EFED has no method to estimate chronic risks to mammals exposed to granular formulations.

Terrestrial Insects

EFED has no method for quantifying risks to non

- target terrestrial insects. Since hydramethylnon is catego rized as practically non

- toxic to non

- target terrestrial insects, risk is expected to be low.

Terrestrial Ecological Incident Data

Currently, there are no terrestrial ecological incidents in the EFED database for hydramethylnon.

### 18 Appendix I

Summary of Environmental Fate and Transport Properties

(1) Degradation

Hydrolysis (MRID 42194701, §161

- 1)

Hydramethylnon is stable to hydrolysis at pH 5, pH 7, and pH 9. The half

- lives are reported as >30 days at all pH values. In addition, the stabil ity of hydramethylnon does not appear to be affected by type or concentration of buffer at pH 7. This study is

classified as Acceptable

.

Photodegradation in Water (MRIDs 42238201 and 42473301, §161

- 2)

The photodegradation in water data indicate that hydramethylnon rapidly photodegrades in pH 7 buffer solutions (half

- life of 1 hour). Hydramethylnon was stable in the dark control treatment. A major photodegradate, 4H

- pyrimido [2

- 1,c]as

- triazio

- 4

- one

- 1,6,7,8

- tetrahydro

- 7,7

- dimethyl

- 3

- [p

- (trifluoromethyl )

- styryl], represented 25.2% and 30.5% of the recovered 14 

### C

- phenyl and 14 

### C

- pyrimidine radioactivity, respectively. A second major degradate, 1,5

- bis(alpha, alpha, alpha

- trifluoro

- p

- tolyl)

- 1,4

- pentadien

- 3

- one, represented 28.0% of recovered phenyl

labeled m aterial. In addition, five unidentified compounds (Unknowns 1, 2, 3, 4, and 5) were discernible in test samples. Unknowns 1, 3, and 4 were detected in the pyrimidine radiolabeled samples and reached concentrations of 9.5, 29.6, and 7.7% of recovered

radioa ctivity, respectively. Unknowns 2 and 4 were detected in the phenyl radiolabeled samples and reached concentrations of 7.6 and 15.6% of recovered radioactivity, respectively. Unknown 2 did not appear in the HPLC analyses of the confirmatory samples, but wa s observed in the rates of formation and decline analyses. Attempts to identify these unknowns by LC/MS are inconclusive.

The status of the photodegradation in water data is Supplemental because the major degradates, Unknowns 3 and 4, present at concentr ations of 29.6% and 15.6% of recovered radioactivity, respectively, were not identified and characterized.

Photodegradation on Soil (MRID 42113401, §161

- 3)

Photodegradation of hydramethylnon was studied using loam soil. First order linear degradation o f the data collected under continuous irradiation provided the half

- life of 25 and 21 days for phenyl and pyrimidyl labels of the parent compound. Under natural sunlight conditions, the respective half

- lives corresponded to 43 and 37 days. Two

unidentifi ed peaks (Unknown A and B possibly representing hydramethylnon epoxide and ketone compounds), both of which comprised 10% of the applied radioactivity, were determined to be a mixture of compounds. The soil photolytic degradation is longer than the aqueou s photolysis. The difference may be due to the rapid adsorption of

### 19 hydramethylnon to the soil and the reduced availability of

### 20 hydramethylnon to photolytic degradation. Hydramethylnon was stable in the dark control treatment. This study is class ified as Acceptable

.

Aerobic Soil Metabolism (MRID 42320801, §162

- 1)

One guideline aerobic soil metabolism study was submitted to the Agency. Hydramethylnon appears to degrade relatively slowly under aerobic conditions when applied to sandy loam soil at the application rate (~0.095 ppm). After 1 year of aerobic

incubation, first

- order half

- lives of 375 and 391 days were reported for the 14 

### C

- phenyl and

14 

### C

- pyrimidine labeled hydramethylnon, respectively. One unidentified degradate, which HPLC analysis indicated to contain both labels and be more polar than the parent compound, was detected at concentrations of 15.6 and 16.8% of applied radioactivity in

the 14 

### C

- phenyl and 14 

### C

- pyrimidine labeled samples, respectively. The study author

believes that forma tion of this degradate was partially due to the soil extraction and analytical methodology of the extracts and that it is unstable. Further attempts to identify this degradate by LS/MS were unsuccessful. In addition, up to 18 minor degradates, all at

conce ntrations <0.004 ppm, were discernible in the soil extracts. Additional information on the identities of the 18 minor degradates is not needed at present because of the low rate of occurrence of these compounds in the study. This study is classified as

Ac ceptable

.

Anaerobic Aquatic Metabolism (MRID 43102701, §162

- 3)

Hydramethylnon appears to be relatively persistent under anaerobic conditions. First order linear degradation half

- lives of 552 and 455 days were calculated for the phenyl and pyrimidine labeled hydramethylnon samples, respectively. The concentration of

1 4 

### C

- phenyl and 14 

### C

- pyrimidine hydramethylnon decreased from 90.7% and 82.6% to 50.4% and 57.4%, respectively, of applied radioactivity by termination of testing period (1 year). Two additional peaks besides parent hydramethylnon were discernible in test

sa mples. Peak A was discernible at maximum concentrations of 15 to 8.8% at 9 and 12 months post

- treatment for phenyl and pyrimidine labeled samples, respectively. Peak A was determined by HPLC and Thin Layer Chromatography (TLC) to be mainly parent hydrameth ylnon. Peak B was determined to be a photolytic product formed during sample analysis. Since Peaks A and B generated multiple peaks during HPLC and liquid

- liquid chromatography, they could not be identified. Peak B was reported to reach a maximum

concentra tion of 12.7% and 9.2% of applied radioactivity at 3 and 4 months
post

- treatment samples in the phenyl and pyrimidine labeled test samples, respectively. The study is classified as Acceptable

.

(2) Mobility (MRID 41888301, MRID 41888302 §163

- 1 )

Two guide line mobility studies were submitted to the Agency. One of these is an unaged adsorption/desorption study, MRID 41888302, and the other is a TLC study, MRID

41888301.

### 21 In the batch equilibrium study (MRID 41888302), hydramethylnon appears to be rel atively

non

- mobile (Kd values ranged from 1039

- 1782 mL/g). In addition, hydramethylnon was reported to be stable since only one major spot, which co

- chromatographed with

non

- labeled hydramethylnon, was discernible on the normal phase assays. Although

the re is a poor correlation between the organic carbon content of the soil and the adsorption coefficients, for the purpose of modeling, the Koc vales were determined as 358276 (loamy sand), 287759 (sandy loam), 123381 (loam), and 95389 (silt loam).

The st rong adsorption properties of hydramethylnon were also observed in soil TLC study (MRID 41888301). The results indicate that hydramethylnon is relatively non

- mobile in loamy sand, sandy loam, loam, and clay loam soils.

Both studies are considered scienti fically valid. However, the Agency does not accept soil TLC mobility data (MRID 41888301) towards mobility data requirement (§163

- 1) so this study is considered Supplemental. The unaged mobility study, MRID 41888302 is Acceptable . Because the current ris k assessment is based on parent alone, no additional information on aged mobility is needed at this time. However, since photolysis appears to be a major route of degradation, aged mobility data for photodegradation products may be needed to support any a dditional uses of hydramethylnon.

(3) Bioaccumulation ( MRID 00101611, §165

- 4)

Hydramethylnon showed some tendency to accumulate in fish tissues with reported bioconcentration factors of 1300X in whole fish, 780X in fillet, and 1900X in viscera. The depur ation was slow with a decrease of approximately, 48 to 63% of residues after a

14

- day clearance period. This study is classified as Supplemental

.

(4) Terrestrial Field Dissipation (MRID 43293101 and MRID 43293102

, §164

- 1)

Two studies using the formula tion product AMDRO conducted in bare soil in Windermere, Florida (MRIDs 43293101) and in Pattison, Texas (MRID 43293102) were submitted to the Agency for guideline requirement §164

- 1. Hydramethylnon appeared to dissipate in

Florida sand soil with a calcul ated first order half

- life of 3 days. Average residues above the analytical detection limit (0.010 ppm) were not detected below the 0

- 6 inch soil depth level. Hydramethylnon residues ranged from 115 ppb at immediately after treatment (0.01 day test interva l) to <10 ppb at 14 days post

- treatment. No attempt was made for the identification of degradation products during the entire testing period of 152 days.

In Texas sandy loam soil, hydramethylnon appeared to dissipate with a first

- order

calculated half

- l ife of 55 days. Average residues above the analytical detection limit (0.010 ppm) were not detected below the 0

- 6 inch soil depth level. Hydramethylnon residues ranged from 114 ppb at immediately after treatment (0.01 day test interval) to <10 ppb at 30 da ys post

- treatment and thereafter, the residues remain close to the detection limit for the entire testing period of 148

### 22 days. Similar to other field dissipation study in Florida, no attempt was made for the identification of degradation products during the entire testing period.

Both field studies are classified as Supplemental

.

(5) Spray Drift

American Cyanamid is a member of the Spray Drift Task Force and is able to cite those data. Although there are aerial broadcast application uses, the granular formulation would not be expected to drift during typical application.

### 23 Structures of Hydramethylnon and its Degradates

### 24

### 25

### 26 Appendix II

Drinking Water and Aquatic Exposure Model Outputs

FIRST Output

RUN No. 1 FOR Hydramethylnon ON Pineapples * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Kd (PPB ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- 3.000( 5.446) 2 120 1669.0 880.0 AERIAL(16.0) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED

(FIELD) RAIN/RUNOFF (RESERVOIR) (RES.

- EFF) (RESER.) (RES ER.)

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

407.60 2 N/A .04

- 4.96 815.20 4.93

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.0 AUG 1, 2001

----------------------------------- --------------------------------- PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)

CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- 76.086 1.447



### Scigrow Output

SCIGROW

VERSION 2.2: NOVEMBER 1, 2001

RUN No. 1 FOR hydramethylnon ** INPUT VALUES **

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

APP RATE APPS/ TOTAL/ SOIL AEROBIC SOIL METAB (LBS/AC) YEAR SEASON KOC HALFLIFE (DAYS)

-------------------------------------------------------- 3.000 2 6.000 205570.0 383.00

GROUND

- WATER SCREENING CONCENTR ATION (IN UG/L

- PPB)

-------------------------------------------------------- .034447

### 27 --------------------------------------------------------

### 28 GENEEC Output

RUN No. 1 FOR Hydramethylnon ON Pineapples * INP UT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE NO

- SPRAY INCORP ONE(MULT) INTERVAL Kd (PPB ) (%DRIFT) ZONE(FT) (IN)

------------------------------ -------------------------------------- 3.000( 5.446) 2 120 1669.0 880.0 AERL_C( 9.2) .0 .0

FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED

(FIELD) RAIN/RUNOFF (POND) (POND

- EFF) (POND) (POND)

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

407.60 2 N/A .04

- 4.96 815.20 4.93

GENERIC EECs (IN MICROGRAMS/LITER (PPB)) Version 2.0 Aug 1, 2001

-------------------------------------------------------------------- PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY

GEEC A VG GEEC AVG GEEC AVG GEEC AVG GEEC

-------------------------------------------------------------------- 15.90 10.75 2.85 1.00 .67

### 29 Appendix III

Ecotoxicity Studies

Toxicity testing rep orted in this section does not represent all species of bird, mammal, or aquatic organism. Only two surrogate species for both freshwater fish and birds are used to represent all freshwater fish (2000+) and bird (680+) species in the United States. For m ammals, acute studies are usually limited to laboratory rats or mice. Estuarine/marine testing is usually limited to a crustacean, a mollusk, and a fish. Also, neither reptiles nor amphibians are tested. The assessment of risk or hazard makes the assump tion that avian and reptilian toxicities are similar. The same assumption is used for fish and amphibians.

I Toxicity To Terrestrial Organisms

( 1) Birds, Acute and Subacute

An acute oral toxicity study using the technical grade of the active ingredient (TGAI) was conducted to establish the toxicity of hydramethylnon to avian species. The preferred test species are the mallard duck (a waterfowl) and the bobwhite quail (an up land gamebird). The results of this study are tabulated below:

Table 1

- Avian Acute Oral Toxicity

Species %ai LD 50 (mg/kg) Toxicity Category MRID Number Study

Classification

Northern

Bobwhite Quail ( Colinus virginianus ) 92% 1828 Slightly toxic 00064576 Core

Mallard Duck ( Anas platyrhynchos ) 92% 2510 Practically non

- toxic

00064575 Core



### Since the LD 50 

### falls in the range of 1828

- 2510 mg/kg, hydramethylnon is slightly toxic to practically non

- toxic to avian species on an acute oral basis. Both acute oral toxicity studies are

classified as Core

.

Two subacute dietary studies using the TGAI were conducte d to establish the toxicity of hydramethylnon to birds. These studies were performed on the two preferred test species, the mallard duck and the bobwhite quail. The results of these tests are tabulated below:

### 30 Table 2

- Avian Subacute Oral Toxi city

Species %ai LC 50 (mg/kg) Toxicity Category MRID Number Study

Classification

Northern

Bobwhite Quail ( Colinus virginianus ) 92% 1136 Slightly toxic 00064577 Core

Mallard Duck ( Anas platyrhynchos ) 92% 4355 Slightly toxic 00085931 Core

1Test organisms observed an additional three days while on untreated feed



### Since the LC 50 

### falls in the range of 1136

- 4355 ppm, hydramethylnon is slightly toxic to avian species on a subacute dietary basis. Both acute dietary studies are classified as Core

.



### (2) Birds, Chronic

Avian reproduction studies are required when birds may be exposed repeatedly or continuously through persistence, bioaccumulation, or mult iple applications. Avian reproduction studies are also required if mammalian reproduction tests indicate a reproductive hazard. The hydramethylnon label calls for multiple applications on pineapples, therefore, avian reproductive studies are required. The results of this test are tabulated below :

Table 3

- Avian Reproduction Toxicity

Species %AI NOAEC (ppm) LOAEC (ppm) Endpoints

Affected MRID Number Study

Classification

Northern

Bobwhite Quail ( Colinus virginianus ) 97.8% > 57.0 57.0 None 45449701 Supplemental 1

Mallard Duck ( Anas platyrhynchos ) 97.8% 28.5 57.0 weight of

14

- day old

survivors 45449702 Core

1 This toxicity study is scientifically sound, but only partially satisfies the guideline requirement for a
bobwhite quail reproductive toxicity study because no reproductive toxicity was shown and, so, a NOAEC

was not identified.



### Although a NOAEC was not determined for the bobwhite quail study, no endpoints were affected and the study is classified as Supplemental . In the case of the mallard duck, the NOAEC was determined to be 28.5 ppm by which the weights of 14

- day old survivors were affected. This study is classified as Core

.

### 31 (3) Mammals, Acute and Chronic

In general, EFED utilizes acute and reproduction toxicity data submitted to HED on laboratory

rodents and/or non

- rodents in evaluating risk for wild mammals. The acute and chronic toxicity

values obtained from rodents are tabulated below:

Table 4

- Mammalian Toxicity ( Acute And Chronic)

Species %AI Test Type Toxicity Value Toxicity Value MRID Number

Norway Rat

( Rattus norvegicus ) 95% LD 50 817(m) 1502 (F) Slightly Toxic 416125

- 03

Norway Rat

( Rattus norvegicus ) 92% 3 rd Generation Reproduction Toxicity test NOAEL=50 ppm LOAEL=100 ppm Male infertility

was noted at 100

ppm 35525

35526

101575



### The results indicate that hydramethylnon is slightly toxic to small mammals on an acute oral basis. Reproductive effects(male infertility) occurred at 100 ppm (NOAEL= 50ppm)

In a three generation study (MRID 43741501), 98.2% hydramethylnon was administered to Sprague

- Dawley rats. The reproductive NOAEL was determined to be 25 ppm and the reproductive LOAEL was determined to be 50 ppm based on histological findings in the testes and

the epididymides. At 75 ppm, reproductive performance of the males was decreased. As noted above, these findings are suggestive of the potential for reproductive effects in other organisms including birds.

(4) Insects

A honey bee acute contact study usin g the TGAI was required for hydramethylnon because its outdoor use may result in honey bee and non

- targeted insect exposure. Results of this test are

tabulated below:

Table 5

- Non

- targeted Acute Contact Toxicity

Species %AI LD 50 ( μ g/bee) Toxicity Category MRID Number Study

Classification

Honey bee (Apis mellifera) 96.8 68.0 Practically

non

- toxic 416078

- 01 Core



### The results indicate that hydramethylnon is practically non

- toxic to bees on an acute contact basis. The study is classified as Core

.

### 32 II. Toxicity To Aquatic Organisms

(1) Freshwater Fish, Acute

Two freshwater fish toxicity studies using the TGAI are required to establish the toxicity of hydramethylnon to freshwater fish. The two preferred species are the rainbow trout (a coldwater fish) and the bluegill sunfish (a warm water fish). Acute toxicity test using channel catfish was

also submi tted to the Agency. The results of these tests are tabulated below:

Table 6

- Freshwater Fish Acute Toxicity

Species %AI 96

- Hour LC 50 (ppb) 1 Toxicity Category MRID Number Study

Classification

Rainbow trout (Oncorhynchus mykiss ) 92 150 Highly toxic 00052857 Core

Bluegill sunfish ( Lepomis

macrochirus ) 92 1700 Moderately toxic 00061708 Core

Channel catfish (Ictalurus
punctatus ) 92 90 Very Highly Toxic 00061707 Core

1 Note: LC 50 concentrations for bluegill sunfish exceed the water solubility of hydramethylnon. These concentrations were achieved through the use
of dimethyl formalin as a co

- solvent



### Because the LC 50 

### falls in the range of 90 to 1700 ppb, hydramethylnon is moderately to very highly toxic to freshwater fishes in an acute basis. Based on the results, catfish appears to be sensitive to toxic effects of hydramethylnon as compared to other species tested. All of the fish acute toxicity tests are classified Core

.

(2) Fr eshwater Fish, Chronic

A freshwater fish early life

- stage test using the TGAI may be required for hydramethylnon

because the end

- use product may be transported to water from the intended use sites and conditions are met with regard to the chemical’s toxic ity. The guideline requirement 72

- 4 is reserved for the hydramethylnon uses on pineapples. This test is expected to be submitted for future expansion of hydramethylnon uses.

(3) Freshwater Invertebrates, Acute

A freshwater aquatic invertebrate toxicity test using the TGAI is required to establish the toxicity of hydramethylnon to aquatic invertebrates. Results of this test are tabulated below:

### 33 Table 7

- Freshwater Invertebrate Acute Toxicity

Species %AI 48

- Hour LC 50 (ppb) Toxicity Category MRID Number Study

Classification

Waterflea
( Daphnia magna ) 92% 1140 Moderately toxic 00035877 Core



### Since the LC 50 

### is 1140 ppb, hydramethylnon is moderately toxic to aquatic invertebrates on an acute basis. The acute Daphnia test is classified Core

.

(4) Freshwater Invertebrates, Chronic

A freshwater aquatic invertebrate life

- cycle testing using the TGAI is required for hydramethylnon because the end

- use product may be transported to water from the

intended use sites . The guideline requirement 72

- 4 is reserved for the hydramethylnon uses on pineapples. This test is expected to be submitted for future ex pansion of hydramethylnon uses.

(5) Estuarine/Marine Fish, Acute

Acute toxicity testing with estuarine/marine fishes using the TGAI of hydramethylnon is required

because the end

- use product is expected to reach estuarine/marine habitats. The preferre d test species is the sheepshead minnow. This data has not been submitted for use in this risk assessment. Therefore, it is listed as a data gap until it is submitted and reviewed.

(6) Estuarine/Marine Fish, Chronic

The guideline requirement 72

- 4 is re served for hydramethylnon uses on pineapples. This test is expected to be submitted for any future proposed uses of hydramethylnon.

(7) Estuarine and Marine Invertebrates, Acute

Acute toxicity testing using estuarine/marine invertebrates using the TGA I of hydramethylnon is required because the end

- use product is expected to reach estuarine/marine habitats. The preferred test species are the mysid shrimp ( Americamysis bahia ) and the eastern oyster
( Crassostrea gigas). Since these studies were not sub mitted, it is listed a data gap until it is

submitted and reviewed for use in future risk assessments.

(8) Estuarine and Marine Invertebrate, Chronic

The guideline requirement 72

- 4 is reserved for the hydramethylnon uses on pineapples. This test is expe cted to be submitted for any future proposed uses of hydramethylnon.

### 34 III Toxicity to Plants

(1) Terrestrial

Currently, terrestrial plant testing is not required for pesticides other than herbicides except on a

case

- by

- case basis ( e.g. , phyto toxicity observed based on incident data or literature). EFED has not requested studies supporting the ecotoxicological and phytotoxicological effects of hydramethylnon on terrestrial plants because the incident database did not show any evidence of phyto toxicity.

(2) Aquatic

Semi

- aquatic plant testing is required if the pesticide is expected to enter into aquatic habitats in significant quantities. Data supporting the ecotoxicological effects of hydramethylnon on

semi

- aquatic plants was not availabl e for use in this risk assessment. The request for the aquatic plant toxicity data is reserved for the proposed uses.

### 35 Appendix IV

Risk Assessment

Risk assessment of a pesticide’s ecological effects integrates the results of exposure and toxicity data to evaluate the likelihood of adverse ecological effects on a non

- target species. The means of integrating these exposure factors is the risk quotient (RQ) method. Risk quotients are calculated by dividing estimated environmental concentrations (EE Cs) of the pesticide by acute and chronic toxicity values. EECs are based on the maximum application rates for that pesticide.

Risk quotients are then compared to the Agency’s levels of concern (LOCs). These LOCs are used to analyze potential risk to n on

- target organisms and the need to consider regulatory action. The criteria are used to indicate when a pesticide used as directed has the potential to cause adverse

effects on non

- target organisms. LOCs currently address the following risk presumption categories: (1) acute : potential for acute risk for all nontarget organisms which may warrant regulatory action in addition to restricted use classification; (2) acute restricted use: potential for acute risk for all nontarget organisms, but may be mitiga ted through restricted use classification; (3) acute endangered species: endangered species may be adversely affected by use; and (4) chronic risk: potential for chronic risk may warrant regulatory action. Currently, the Agency does

not assess chronic ris k to plants, acute and chronic risks to non

- target insects, or chronic risk from granular/bait formulations to birds or mammals. In addition, the Agency considers any incident data that is submitted concerning adverse effects on non

- target species.

### 36 RQ Calculations, LOCs, and Risk Presumptions for Terrestrial Animals

Risk Presumption RQ LOC

Birds

Acute Risk

Acute Restricted Use

Acute Endangered Species

Chronic Risk EEC 1 /LC 50 , LD 50 /sq ft 2 or LD 50 /day 3

EEC/LC 50 , LD 50 /sq ft or LD 50 /day (or LD 50 < 50 mg/kg)

EEC/LC 50 , LD 50 /sq ft or LD50/day

EEC/NOAEC 0.5

0.2

0.1

1

Wild Mammals

Acute Risk

Acute Restricted Use

Acute Endangered Species

Chronic Risk EEC/LC 50 , LD 50 /sq ft or LD 50 /day

EEC/LC 50 , LD 50 /sq ft or LD 50 /day (or LD 50 < 50 mg/kg)

EEC/LC 50 , LD 50 /sq ft or LD 50 /day

EEC/NOAEC 0.5

0.2

0.1

1

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

2 mg/ft 2 3 mg of toxicant consumed/day

LD 50 * wt. of bird LD 50 * wt. of bird

RQ Calculations, LOCs, and Risk Presumptions for Aquatic Animals

Risk Presumption RQ LOC

Acute Risk

Acute Restricted Use

Acute Endangered Species

Chronic Risk EEC/(LC 50 or EC 50 )

EEC/(LC 50 or EC 50 )

EEC/(LC 50 or EC 50 )

EEC/(NOAEC) 0.5

0.1

0.05

1

RQ Calculations, LOCs, and Risk Presumptions for Plants

Risk Presumption RQ LOC

Terrestrial and Semi

- Aquatic Plants

Acute Risk

Acute Endangered Species EEC 1 /EC 25
EEC/EC 05 or NOAEC 1

1

Aquatic Plants

Acute High Risk

Acute Endangered Species EEC 2 /EC 50
EEC/EC 05 or NOAEC 1

1

1 EEC = lbs a.i./A

2 EEC = (ppb/ppm) in water

### 37 Appendix V

Data Requirements

Table 1: Status of Environmental Fate Study Requirements for Hydramethylnon

Guideline # Data Requirement Study

Classificatio

n MRID #’s Is Guideline

Requirement

Satisfied?

161

- 1 Hydrolysis Acceptable 42194701 Yes

161

- 2 Aquatic Photolysis Supplementa

l 42238201

42473301 No 1

161

- 3 Soil Photolysis Acceptable 42113401

Yes

162

- 1 Aerobic Soil Metabolism Acceptable 42320801 Yes

162

- 3 Anaerobic Aquatic

Metabolism Acceptable 43102701 Yes

162

- 4 Aerobic Aquatic

Metabolism N/A N/A No 2

163

- 1 Leaching

- Adsorption/De

sorption Acceptable

Supplementa

l 41888302

41888301 Yes

164

- 1 Terrestrial Field

Dissipation Supplementa

l 43293101

43293102 No 1

165

- 4 Accumulation in Fish Acceptable 00101611 Yes

1 Degradate information needed. Major degradates are not characterized.

2 Reserved for this registration action on pineapples

### 38 Table 2: Status of Ecological Study Requirements for Hydramethylnon

Study

Guideline Data Requirement Study

Classification MRID # Is Guideline

Requirement

Satisfied

Birds

71

- 1a Avian acute oral

Bobwhite quail Core 00064576 Yes

71

- 1b Avian acute oral

Mallard duck Core 00064575 Yes

71

- 2a Avian subacute dietary

Bobwhite quail Core 00064577 Yes

71

- 2b Avian subacute dietary

Mallard duck Core 00085931 Yes

71

- 4a Avian reproduction

Bobwhite quail Supplemental 45449701 No 1

71

- 4b Avian reproduction

Mallard duck Core 45449702 Yes

Fish and Invertebrates

72

- 1a Freshwater fish acute

Bluegill sunfish

Catfish Core

Core 00061708

00061707 Yes

72

- 1c Freshwater fish acute

Rainbow trout Core 00052857 Yes

72

- 2 Freshwater acute

invertebrate, Daphnia Core 00035877 Yes

72

- 3a Estuarine/marine acute fish

Sheepshead minnow - None No

72

- 3b Estuarine/marine acute

invertebrate, Eastern oyster - None No

72

- 3c Estuarine/marine acute

invertebrate, Mysid - None No

72

- 4a Freshwater fish, early

- life

stage

Fathead minnow - None Reserved 2

### 39 Table 2: Status of Ecological Study Requirements for Hydramethylnon

Study

Guideline Data Requirement Study

Classification MRID # Is Guideline

Requirement

Satisfied

72

- 4b Freshwater invertebrate life

cycle, Daphnia - None Reserved 2

72

- 4c Estuarine/marine fish early

life

- stage, Sheepshead

minnow - None Reserved 2

72

- 4d Estuarine/marine life cycle

Mysid - None Reserved 2

Plants

122

- 1a Terrestrial plants

Seedling emergence - None Reserved 3

122

- 1b Terrestrial plants

Vegetative vigor - None Reserved 3

122

- 2 Aquatic plants

- None Reserved 2

Non

- target Insects

141

- 1 Acute honey

- bee contact Core 41607801 Yes

1 Partially satisfied as the NOAEC not established.

2 Reserved for pineapple uses.

3 Requested on a case by case basis for pesticides other than herbicides.