UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, 

PESTICIDES, AND TOXIC SUBSTANCES

Environmental Fate and Ecological Risk Assessment for the 

Proposed New Use Registration of Metaflumizone for 

Control of Fire Ants in Citrus/Nut Orchards, Grape 

Vineyards, Nurseries, and Agricultural/Residential Areas

F

F

F

N N

N

O

O

F

F

F

N

Metaflumizone: E-Isomer

F

F

F

N

N

N

O

N

O

F

F

F

Metaflumizone: Z-Isomer

A Mixture of E and Z Isomers with an E:Z ratio of 12:1

Prepared by:

Keith G. Sappington, M.S.

Mohammed A. Ruhman, Ph.D.

Reviewed by:

Mah Shamim, Ph.D.

United States Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch V

1200 Pennsylvania Ave.

Mail Code 7507P

Washington, D.C. 20460
2

I. INTRODUCTION............................................................................................................. 3

II. ECOLOGICAL RISK CONCLUSIONS........................................................................ 3

A. Direct Consumption of Granules.....................................................................................................................3

B. Aquatic Organism and Bioaccumulation Risks...............................................................................................4

III. RISK CHARACTERIZATION....................................................................................... 4

A. Risks to Terrestrial Organisms........................................................................................................................4

1. Direct Consumption of Metaflumizone Fire Ant Bait Granules.......................................................................5

2. Consumption of Food Items that have Bioaccumulated Metaflumizone ..........................................................8

B. Risks to Aquatic Organisms..........................................................................................................................10

IV. REFERENCES................................................................................................................ 11

APPENDIX A. Calculations for Determining Risk to Terrestrial Organisms Resulting 

from Direct Consumption of Metaflumizone Fire Ant Bait Granules................................... 13

APPENDIX B. Calculations for Determining Risk to Terrestrial Organisms Resulting 

from Consumption of Soil Invertebrates that have Bioaccumulated Metaflumizone.......... 25

APPENDIX C. Summary of Available Toxicity Data for Metaflumizone ........................... 33

APPENDIX D. Estimating Ecological Surface Water Exposure EECs................................. 37

APPENDIX E. Summary of Persistent, Bioaccumulative, and Toxic Properties of 

Metaflumizone............................................................................................................................. 40

APPENDIX F. Calculations for Determining Risk to Birds and Mammals Resulting from 

Consumption of Aquatic Organisms that have Bioaccumulated Metaflumizone................. 41
3

I. INTRODUCTION

The Environmental Fate and Effects Division (EFED) has completed its risk assessment (DP Barcode: 

345127) for the Section 3 registration of the active ingredient metaflumizone (Altrevin Insecticide Fire 

Ant Bait) for control of fire ants in citrus orchards, tree nut orchards, grape vineyards and nurseries in 

citrus orchards, tree nut orchards, and grape vineyards in addition to many other non-food uses such as 

nurseries, lawns, public and home landscape/recreational areas, grounds surrounding agricultural 

structures, golf courses and sod farms. 

Metaflumizone ((E+Z)-2-[2-(4-Cyanophenyl)-1-[3-(trifluoromethyl) phenyl]ethylidene]-N-[4-

(trifluoromethoxy)phenyl] hydrazinecarboxamide (CAS 139968-49-3) belongs to the semicarbazone class 

of pesticides, and is a stereo-isomeric insecticide that is a mixture of E and Z isomers at a ratio of 

nearly12:1. Metaflumizone is a voltage-dependent sodium channel blocker that blocks the sodium 

channel and inhibits nerve impulses leading to inhibited feeding and paralysis in susceptible insects such 

as Lepidoptera and Coleoptera. It is further characterized by its very low solubility (1.79 ppb), very high 

affinity to soil/sediment (Koc value of 30,753), high persistence in the soil and water/sediment systems 

(90th percentile t1⁄2 = 134 and t1⁄2 = >378 days, respectively), and relatively high bioaccumulation in 

aquatic organisms (bioconcentration factors from 3500x in edible tissues and 12,000x in nonedible tissues 

of fish). Combined with its high toxicity to avian species, the aforementioned characteristics of 

metaflumizone are consistent with criteria used to classify chemicals as being Persistent, 

Bioaccumulative, and Toxic (PBT; Appendix E).

The end-use product (Altrevin Insecticide Fire Ant Bait) is an insecticidal bait composition comprised of 

corn-grit granules coated with soybean oil and 0.063% (by wt.) active ingredient. This formulation is 

proposed for use on citrus orchards, tree nut orchards, and grape vineyards in addition to many other nonfood uses such as nurseries, lawns, public and home landscape/recreational areas, grounds surrounding 

agricultural structures, golf courses and sod farms to control imported and native fire ants (Solenopsis 

spp). The formulations can be broadcasted uniformly by using a hand-held or walk-behind spreader or 

applied uniformly around the perimeter of individual mounds. The labels indicate that the use rates 

should not exceed 2 oz/mound when the bait is applied to individual mounds, but do not explicitly state 

whether multiple treatments are allowed under this application method. For this risk assessment, it was 

assumed that only a single treatment is allowed under the current labels when applying to individual 

mounds. If this assumption is not reflected in reality then this risk assessment likely underestimates 

exposure and risk under the mound application exposure scenario. The labels do state that for broadcast 

treatments, a single treatment should not exceed 1.5 lb formulation/A (0.00095 lbs a.i./A), and a

maximum of four applications may be made per year at intervals ranging from four to eight weeks; 

therefore, a maximum rate of 6 lbs formulation/A/year (0.0038lbs a.i./A/year) is allowed under the current 

labels. 

II. ECOLOGICAL RISK CONCLUSIONS

A. Direct Consumption of Granules 

Acute risks to mammals from direct consumption of granules could not be estimated in this assessment

due to lack of toxicity at the highest test concentration in the acute oral toxicity study. Regarding risks to 

mammals from chronic exposures via consumption of granules, the refined analysis indicates chronic 

exposure and risk to mammals appears to be relatively low, particularly for larger mammals. However, 

acute and chronic risks to avian species cannot be completely discounted. Assuming that the granules are 

available for avian consumption following treatment, our modeling suggests that the use of 
4

metaflumizone ant bait poses an acute and chronic risk to avian species via this pathway (see Risk 

Characterization Section and Appendix A). The assumption of availability of granules for direct 

consumption is important to the results of this risk assessment and involves some uncertainty due to 

conflicting information. Specifically, we are aware of information suggesting that wildlife exposure to 

granules would be minimized by the rapid foraging activity of fire ants on the bait (bringing it into the 

mound) and/or avoidance of wildlife of fire ant-infested areas. On the other hand, we are aware of several 

ecological incidents that have been associated with fire ant control with granulated pesticide products in 

addition to studies that indicate wildlife do forage in areas containing fire ant activity. 

B. Aquatic Organism and Bioaccumulation Risks. 

The maximum acute RQ for all aquatic organisms exposed to metaflumizone solely through the water 

column are be less than the acute endangered species LOC (0.05 for animals and 1 for plants), even if all 

acute toxic effects to water column-dwelling invertebrates, water column dwelling and benthic fish, and 

aquatic vascular plants are assumed to occur at the limit of solubility (1.79 ppb). In addition, chronic tests 

that were submitted with estuarine/marine fish and freshwater invertebrates did not show any signs of 

toxicity at or below the maximum 1-in-10 year peak concentration from PRZM/EXAMS (0.021 ppb), and 

therefore, risk to these taxonomic groups due solely to exposure from metaflumizone freely-dissolved in 

water is not expected. Although the toxicity data upon which these risks were quantified do not account 

for exposure via the diet which appears significant for metaflumizone, the aquatic organism risk findings 

do not appear be sensitive to the absence of this exposure pathway due primarily to the very low 

concentrations predicted in aquatic ecosystems. 

To address the bioaccumulative characteristics of metaflumizone and potential secondary exposure to 

piscivorous wildlife, concentrations in representative organisms of an aquatic food web were predicted 

using a bioaccumulation model. Results from this analysis indicate that acute and chronic risks to avian 

species are unlikely via consumption of contaminated aquatic prey. Similarly, results indicate that 

chronic risks to mammalian species are unlikely via this exposure pathway. Similarly, an analysis of the 

potential metaflumizone bioconcentration in earthworms also indicates that exposure and risks to 

insectivorous birds and mammals are substantially below the Agency’s levels of concern for endangered 

species.

III. RISK CHARACTERIZATION 

A. Risks to Terrestrial Organisms

The toxicity reference values for terrestrial organisms exposed to metaflumizone are provided in Table 

C-1 of Appendix C. However, given the apparent low sensitivity of earthworms and plants to 

metaflumizone, the low likelihood of significant exposure of flying non-target insects to granular 

metaflumizone, and the low application rate of metaflumizone fire ant bait (0.00095 lbs a.i./A), the focus 

of the terrestrial organism risk assessment is on birds and mammals. 

As can be seen in Table C-1 of Appendix C, there are no dose-based chronic toxicity endpoints available 

for birds, and therefore, chronic risk to avian receptors was based solely on dietary toxicity data. In 

addition, there are no definitive acute toxicity values available for mammals; the LD50 value was set as

greater than the highest treatment level of metaflumizone and no acute dietary studies with mammals 

were available. Therefore, acute risk to mammals resulting from exposure to granular metaflumizone fire 

ant bait could not be quantified in this assessment. Although in some instances it might be appropriate to 

use the non-definitive LD50 value as a screen for risk, EFED has concern regarding the characterization of 
5

the risk of metaflumizone to mammals because there are no dietary-based data. Based on the comparison 

of acute dose-based toxicity data (LD50 >2025 mg a.i./kg body weight; no mortality at any test level) and 

dietary-based toxicity data (>73.8 mg/kg-bw when expressed as daily dose equivalents; 70% mortality at 

next highest dose) for avian species, it appears that absorption of metaflumizone may be rate-limited and 

the effects and risk to mammals could be significantly underestimated due to reliance on the oral gavage 

studies. In addition, metabolism studies in mammals demonstrated low absorption when dosed: 0.7 to 

7.2% of doses were absorbed in rats and 69-84% of doses were excreted in goats. Therefore, dietary 

exposure for mammals could elicit much more pronounced effects than exposure via oral gavage due to 

the absorption kinetics of metaflumizone, despite that it is more common to observe the opposite. 

Although a bird’s or mammal’s habitat is not limited to a square foot, there is presumably a direct 

correlation between the concentration of a pesticide in the environment (mg/ft2) and the chance that an 

animal will be exposed to a concentration that could adversely affect its survival. Typically for granular 

applications, terrestrial EECs and acute risk quotient values are calculated based on an estimation of 

loadings of pesticide per unit area. This approach compares the available mass of pesticide per square 

foot to the acute oral dose for toxicity (LD50) (Further description of the mg/ft2index is provided in U.S. 

EPA, 2004, and U.S. EPA, 1992). 

However, because definitive LD50 values were not established for birds or mammals (there were no 

mortalities or sub-lethal effects in any of the acute oral studies), the LD50 ft-2analysis could not be 

performed for metaflumizone. The LD50 ft-2index is also based on the assumption that there is a direct 

correlation between the concentrations of a pesticide in the environment (mg/ft2) and the chance or 

probability that an animal will be exposed to a concentration that could adversely affect its survival. For 

metaflumizone fire ant bait applications, this basic assumption may not hold because it is formulated as 

an attractant and a significant amount of this attractive food item may be concentrated in a particular spot 

(ant mounds). Because both of these factors are expected to weaken the strength of the assumed 

correlation underlying the LD50 ft-2analysis, this analysis was not expected to provide reliable risk 

estimates and was not used for metaflumizone. In addition, EFED does not currently have any standard 

methodology for evaluating chronic exposure to granular pesticides and risk to terrestrial wildlife.

However, there is the potential for acute and chronic exposure of birds and mammals to granular 

metaflumizone used for fire ant bait. While terrestrial organisms may also be exposed by other routes, 

such as incidental ingestion of contaminated soil, dermal contact with treated granular surfaces and soil 

during activities in the treated areas, preening activities, and ingestion of drinking water contaminated 

with pesticide, the primary route of exposure to metaflumizone granules will likely be via the oral route 

because it is not volatile and it is not expected to appreciably absorb through the skin. Therefore, for this 

assessment, two routes of exposure were considered to evaluate risk to birds and mammals; direct 

ingestion of granules and consumption of contaminated food items that have bioaccumulated

metaflumizone.

1. Direct Consumption of Metaflumizone Fire Ant Bait Granules

Screening-Level Analysis

In order to derive an upper bound, screening-level estimate of acute and chronic exposure and risk to 

granular metaflumizone for birds and mammals, it was assumed that metaflumizone ant bait is an 

attractive food item and that 100% of avian and mammalian diets are comprised of fire ant bait granules. 

Based on these assumptions, the dietary-based estimated environmental concentration (EEC) for direct 

ingestion of metaflumizone granules is equal to the number of milligrams of active ingredient in one 

kilogram of granules (formulated product). Given the percent active ingredient (0.063%), the EEC is 

equivalent to 630 mg/kg food item (ppm). By comparing this estimated concentration to the
6

corresponding acute and chronic dietary toxicity reference values for birds (LC50>156 mg/kg-diet for 

birds (MRID 46264428); NOAEC = 7.6 mg/kg-diet; MRID 46264430) and chronic dietary toxicity value 

for mammals (NOAEC = 400 mg/kg-diet; MRID 46264315), acute and chronic RQs were calculated and 

compared to the Agency’s established acute and chronic levels of concern (LOCs). Subsequently, the 

acute dietary RQ for birds resulting from exposure to granular metaflumizone was <4.04, and the 

Agency’s LOCs for acute risk (0.5), acute restricted use (LOC 0.2), and acute endangered species (LOC 

0.1) were all exceeded. The chronic RQs for birds and mammals were 82.9 and 1.6, respectively, and the 

Agency’s chronic risk LOC (1) was exceeded for both taxonomic groups.

Although it should be noted that there is some uncertainty regarding acute dietary risk to birds (all RQs 

are less than the reported values) because the LC50 of >156 ppm a.i. from the subacute dietary study with 

mallard ducks (MRID 46264428) was used to perform the analyses for metaflumizone fire ant bait, the 

results of the study clearly indicate significant mortality above the 156 ppm a.i. treatment group; there 

was 0, 0, 70, 40, 30, 50, and 90% mortality after 11 days in the control and 156, 309, 638, 1228, 2538, 

and 4999 mg a.i./kg-diet treatment groups, respectively. Therefore, due to the non-concentration 

response pattern of mortality, the probit, binomial, and moving average methods could not reliably 

generate sound LC50, 95% C.I., and slope estimates, and the conservative value of >156 ppm a.i. was used 

to determine acute dietary risk to avian species. 

Refined Analysis

In addition, the assumption that avian and mammalian diets are 100% ant bait granules obviously 

represents a conservative scenario due to species-specific feeding habits and dietary requirements. 

Therefore, EFED has taken steps to further refine and characterize the potential for acute and chronic risk 

to avian and mammalian species by evaluating how many granules would need to be consumed and how 

much area would need to be foraged to achieve the amount of metaflumizone necessary to trigger the 

Agency’s Levels of Concern (LOCs). Based on the refined analyses (Appendix A) with the most 

sensitive toxicity endpoints available, acute exposure resulting from direct ingestion of fire ant bait 

granules appears to be quite possible and there is reasonable evidence that suggests that the use of 

metaflumizone ant bait poses an acute risk to avian species. Specifically, the calculations with the 

avian median lethal dose equivalents from diet reveal that smaller birds (20g and 100g) are potentially at 

risk, while larger birds (1000g) appear to be at lower risk (Tables A-4, A-5, A-6 in Appendix A). 

For instance, it was estimated that it would take a 20g bird 9 minutes to consume 110 granules, enough 

granules to achieve an EEC equivalent dose that would result in an exceedance of the endangered species 

LOC. Based on the maximum application rate, this number of granules could be gleaned from 11, 21, or 

106 square feet when assuming a 100%, 50%, or 10% feeding efficiency, respectively. In addition, this 

number of granules constitutes only 0.3% of the granules that could be applied to a single fire ant mound. 

To achieve an EEC equivalent dose that would result in an exceedance of the acute risk LOC for un-listed 

species (RQ > 0.5), a 20g bird would have to consume 552 granules. It was estimated that this number of 

granules could be consumed in approximately 46 minutes, and over an area of 53, 106, or 531 square feet 

when assuming a 100%, 50%, or 10% feeding efficiency, respectively. Likewise, this number of granules 

constitutes only 1.5% of the granules that could be applied to a fire ant mound.

At the other end of the spectrum, it was estimated using the avian median lethal dose equivalents from 

diet that it would take a 1000g bird 14 hours to consume 9925 granules, enough granules to achieve an 

EEC equivalent dose that would result in an exceedance of the endangered species LOC. Based on the 

maximum application rate, this number of granules could be gleaned from 954, 1909, or 9543 square feet 

when assuming a 100%, 50%, or 10% feeding efficiency, respectively. In addition, this number of 

granules constitutes 26.3% of the granules that could be applied to a single fire ant mound. To achieve an 

EEC equivalent dose that would result in an exceedance of the acute risk LOC, a 1000g bird would have 
7

to consume 49,623 granules. It was estimated that this number of granules could be consumed in 

approximately 69 hours, and over an area of 4771, 9543, or 47,715 square feet when assuming a 100%, 

50%, or 10% feeding efficiency, respectively. Likewise, this number of granules constitutes 131.4% of 

the granules that could be applied to a fire ant mound.

Based on the refined analyses, chronic exposure resulting from direct ingestion of fire ant bait granules 

appears to be possible. Specifically, the calculations with the most sensitive available NOAEC available 

for birds reveal that it would take 20g, 100g, and 1000g birds 15, 44, and 194 minutes to consume 183, 

523, and 2333 granules, respectively, to achieve a dietary EEC that would result in an exceedance of the 

chronic risk LOC (Table A-7 in Appendix A). The number of granules needed to reach the chronic risk 

LOC for 20g, 100g, and 1000g birds, correspond to 0.5%, 1.4%, and 6.2% of the granules that could be 

applied to a single fire ant mound. In addition, based on the maximum application rate, the number of 

granules needed to reach the chronic risk LOC for 20g, 100g, and 1000g birds could be gleaned anywhere 

from 18 to 176, 50 to 503, and 224 to 2244 square feet, respectively, depending on the feeding efficiency 

of the bird. 

Using the most sensitive available NOAEL for mammals, it was estimated that for 15g, 35g, and 1000g 

mammals, 58, 110, and 1357 minutes would be needed to consume 698, 1318, and 16287 granules, 

respectively, to achieve an EEC equivalent dose that would result in an exceedance of the chronic risk 

LOC (Table A-11 in Appendix A). The number of granules needed to reach the chronic risk LOC for 

15g, 35g, and 1000g mammals, correspond to 1.8%, 3.5%, and 43.1% of the granules that could be 

applied to a single fire ant mound. In addition, based on the maximum application rate, the number of 

granules needed to reach the chronic risk LOC for 15g, 35g, and 1000g mammals could be gleaned 

anywhere from 67 to 671, 127 to 1267, and 1566 to 15660 square feet, respectively, depending on the 

feeding efficiency of the mammal. 

Risk Assessment Uncertainty

Although it seems reasonable to assume that metaflumizone ant bait may be consumed by non-target 

terrestrial wildlife because it is formulated as an attractant to ants and is comprised of corn-grit granules 

coated with soybean oil, the potential for significant acute and chronic exposure of terrestrial wildlife to 

ant bait granules may be reduced under certain application practices. For example, risks would likely be 

reduced if the product not be applied prophylactically. If metaflumizone fire ant bait application is applied 

only when fire ants are actively foraging, then there is the potential for a significant reduction in acute and 

chronic exposures to birds and mammals. The potential for exposure will remain for both transport to 

water and direct ingestion by birds and mammals from the broadcast use because some bait may be 

overlooked during foraging by fire ants. However, the presence of active fire ants on the field should help 

to decrease exposure of non-target wildlife.

Fire ants are extremely aggressive and any movement of particles comprising a fire ant mound typically 

results in an extremely effective defensive "frenzy" from fire ants with anything on or close to the mound 

being attacked. Fire ants are often able to out-compete other wildlife that shares the same ecosystem; the 

presence of actively foraging fire ants often results in diminished levels of other wildlife routinely feeding 

in the area (Allen et al. 2004; Allen et al. 2000; Lechner and Ribble 1996). Thus, it may be unlikely that 

any wildlife will feed on or near fire ant mounds and the presence of fire ants alone may result in reduced 

exposure of non-target wildlife to metaflumizone fire ant bait via competitive exclusion (Dr. Gold of 

Texas A&M University, personal communication), assuming that the bait is not so effective that it kills 

the entire mound prior to complete removal of the product from the presence of non-target wildlife. 

Furthermore, according to researchers with the Texas A&M Fire Ant program, it is expected that 

exposure of non-target wildlife to metaflumizone should also be reduced when actively foraging fire ants 

are present due to their voracious foraging behavior. It is expected that that most of the fire ant bait 
8

would be picked up by the fire ants within an hour of application and that birds and mammals would have 

a difficult time quickly finding the bait given the size of the granules (Dr. Gold of Texas A&M 

University, personal communication).

However, other evidence suggests that non-target exposure may not be reduced by the presence of fire 

ants alone and that some exposure could still occur. Several incident reports have associated reported 

wildlife mortality with the use of other granular-based insecticides for fire ant control (e.g., I013135-001, 

I012500-001, I008779-002, I013623-001). These incident reports suggest that birds and mammals may 

not completely avoid areas inhabited by fire ants and that exposure of some wildlife to metaflumizone fire 

ant bait granules could occur following application. While it remains unclear as to whether the groundfeeding birds that experienced mortality in the reported incidents consumed the granules directly, ingested 

contaminated food items that bioaccumulated metaflumizone, or were exposed via some other exposure 

pathway, these incident reports indicate that potentially significant mortality of non-target wildlife may 

occur following the application of granular pesticides for control of fire ants. In addition, published 

studies also demonstrate that long-term population trends of some species of birds may not be adversely 

affected by fire ants and that some mammals may not exhibit avoidance of fire ant infested areas 

(Pedersen et al.2003; Kopachena et al. 2000; Lechner and Ribble 1996).

In consideration of the above information, it appears likely that small and medium sized birds are 

primarily at acute risk of direct exposure via consumption of granules if metaflumizone fire ant bait is 

applied only when fire ants are actively foraging, because 20g and 100g birds can achieve an EEC 

equivalent dose to exceed all acute LOCs within a single hour of feeding (Tables A-4 & A-5 in 

Appendix A). 20g and 100g birds can also achieve a dietary EEC that would result in an exceedance of 

the chronic risk LOC within a single hour (Table A-7 in Appendix A). Although long-term exposure to 

this dietary EEC is not expected due to the territoriality and efficient foraging of fire ants, it cannot 

definitively be stated that a single-day exposure will not trigger any reproductive effect if the EEC is 

reached. Therefore, potential reproductive effects cannot be completely discounted.

Other sources of uncertainty surrounding the exposure and risk of non-target wildlife to metaflumizone 

ant bait include: (1) lack of knowledge regarding aggregate exposure (e.g., direct consumption of 

granules, ingestion of granules that adhere to soil invertebrates, partitioning of dissolved metaflumizone 

to on-site sources of wildlife drinking water, and dermal exposure of granules released to surrounding soil 

and on-site puddles) and (2) temperature dependence of fire ant bait retrieval1 which may lead to 

prolonged availability of fire ant bait. 

2. Consumption of Food Items that have Bioaccumulated Metaflumizone

Bioaccumulation in Aquatic Organisms

Based on the available environmental fate data it can be concluded that metaflumizone is highly stable to 

biodegradation and there is the potential for bioconcentration/bioaccumulation in aquatic and terrestrial 

systems (Appendix E). Due to the relatively low mobility of metaflumizone (Koc range = 16,534 to 

51,031 L kg -1), it is not expected to leach substantially into groundwater, but it may reach adjacent bodies 

of water via runoff events accompanied by erosion. Once there, metaflumizone may be expected to 

remain adsorbed to suspended solids in the water column, and eventually transported to the bottom 

sediment, where it would accumulate.

Based on the available data, it appears that metaflumizone has potential to bioaccumulate substantially in 

aquatic food webs, with a relatively high octanol/water partition coefficient (KOW= 125,893 for the main 

 

1

http://www.ext.vt.edu/pubs/entomology/444-284/444-284.html
9

E isomer and 25,119 for the Z isomer) and BCF (3500x in edible tissues and 12,000x in nonedible 

tissues), and a relatively slow rate of depuration (after 56 days of depuration, [14C]residues in the fish had 

decreased by ≥85% of maximum). In addition, it should be noted that a steady-state was not achieved in 

the bioconcentration study even after a 42-day exposure period, and therefore, these BCF values could 

underestimate the potential for bioconcentration.

A recent FIFRA Scientific Advisory Panel (SAP) meeting on persistent, bioaccumulative and toxic (PBT) 

chemicals affirmed the need to use alternative methods to the BCF for assessing exposure and risk from 

pesticides with PBT characteristics2. Because aquatic invertebrate-eating and fish-eating wildlife have 

the potential to be exposed to chemicals that may accumulate or persist in their diet, the KOW (based) 

Aquatic BioAccumulation Model (KABAM) version 1.0 was used (USEPA 2009). Specifically, 

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. The bioaccumulation portion of KABAM is based upon Arnot and 

Gobas (2004) who parameterized a bioaccumulation model based on PCBs and some pesticides (e.g., 

lindane, DDT) in freshwater aquatic ecosystems. KABAM was used to estimate metaflumizone 

concentrations in aquatic invertebrate and whole-fish tissues (see Appendix F for model input parameters 

and ouput). Maximum bioavailable concentrations of metaflumizone in water (freely dissolved) and 

sediment was assumed to be equivalent to the 60-d average 1-in-10 year concentrations predicted by 

PRZM/EXAMS (0.0092 ppb for surface water and 0.0072 ppb for pore water; Table 1 below).

For metaflumizone fire ant bait use, the KABAM model predicted concentrations of metaflumizone in 

zooplankton, benthic invertebrates, small forage fish, medium forage fish and piscivorous fish of 

approximately 0.04, 0.05, 0.07, 0.09 and 0.13 mg/kg w.w., respectively. These concentrations are 

substantially below the most sensitive NOAEC for birds (7.6 ppm) or mammals (400 ppm) and thus, are 

not expected to exceed chronic risk levels of concern. In addition, the body-burdens of invertebrates and 

fish are predicted to be several orders of magnitude below levels that may be acutely toxic to birds (LC50

>156 ppm). The low concentrations predicted in aquatic organisms primarily result from the low

application rate of the product (0.00925 lb ai/A). Measured and predicted bioconcentration factors are 

similar, which indicates that model assumptions are reasonable. Therefore, based on these analyses, 

risk estimates for invertebrate and fish-eating birds and mammals are below the LOCs for acute 

risk (0.5), acute restricted use (LOC 0.2), acute endangered species (LOC 0.1), and chronic risk (1).

Additional details of the bioaccumulation modeling are provided in Appendix F.

Bioaccumulation in Earthworms 

Due to the nature of this chemical’s properties, risk to insectivorous terrestrial organisms that may 

consume soil invertebrates that have bioaccumulated metaflumizone was evaluated. This approach 

involved estimating concentrations of metaflumizone earthworms using a fugacity-based (equilibrium 

partitioning) approach based on the work of Trapp and McFarlane (1995) and Mackay and Paterson 

(1981), and then comparing the estimated concentration to the most sensitive toxicity endpoints for birds 

and mammals (details provided in Appendix B). Based on this approach, EFED found that the estimated 

earthworm residue for insectivorous avian receptors (0.04 ppm) is less than the avian chronic dietary 

NOAEL (7.6 ppm) and is less than one-thousandth of the acute diet-based LC50 (>156 ppm) for granular 

metaflumizone applications. Further, the acute dose-based, acute diet-based and chronic diet-based RQs 

for birds are less than or equal to 0.006, which is well below LOCs for acute risk (0.5), acute restricted 

use (LOC 0.2), and acute endangered species (LOC 0.1). Therefore, acute (dose- and dietary-based) and 

chronic risks to birds associated with ingestion of earthworms that have bioaccumulated metaflumizone 

granules are not expected.

 

2

http://epa.gov/oscpmont/sap/meetings/2008/102808_mtg.htm
10

Chronic risks for insectivorous mammals were estimated by considering both dietary- and dose-related 

exposures and effects. Based on the dietary method, chronic LOCs are not exceeded for insectivorous 

mammals because the earthworm residue concentration (0.04 ppm) is less than the most sensitive 

NOAEC (400 ppm). Similarly, based on the dose-based method, the estimated chronic dose-based EECs 

(0.06 mg/kg-bw/d) for insectivorous mammals are well below the applicable toxicity values (44 mg/kgbw/d), resulting in an RQ value of 0.001. The results of the assessment indicate that, when risk for 

mammals is assessed on the basis of daily ingested dietary dose or dietary concentration, the 

accumulation of metaflumizone in earthworms does not, by itself, represent a biologically significant 

pathway for exposure. 

In conclusion, the results of the assessment indicate that the accumulation of metaflumizone in 

earthworms does not, by itself, represent a biologically significant pathway for exposure of birds and 

mammals. Therefore, acute and chronic risks to birds and mammals associated with ingestion of 

earthworms that have bioaccumulated metaflumizone granules are not expected. 

B. Risks to Aquatic Organisms

The toxicity reference values for aquatic organisms exposed to metaflumizone are provided in Table C-2 

of Appendix C. There was a high degree of uncertainty associated with the aquatic data set. All acute 

tests with metaflumizone TGAI and water column-dwelling invertebrates, water column dwelling and 

benthic fish, and aquatic vascular plants did not base exposure and effects levels on properly centrifuged 

supernatant. Therefore, the extent to which measured concentrations of metaflumizone reflect the 

dissolved (bioavailable) fraction from these tests is uncertain. As a conservative assumption for use in 

this risk assessment, all effects observed in the studies were assumed to occur at the limit of aqueous 

solubility (1.79 ppb). Chronic toxicity data for freshwater fish and estuarine/marine invertebrates are not 

available, and although the chronic tests with estuarine/marine fish and freshwater invertebrates did not 

show any signs of toxicity, estimates of exposure levels and toxicity are similarly considered unreliable. 

Despite the uncertainties surrounding the assessment of toxicity of water-column exposure to aquatic 

organisms, the1-in-10 year peak concentration from PRZM/EXAMS from agricultural uses (0.019 ppb

for S. TX Grapefruit; Table 1) is approximately 1% of metaflumizone’s limit of solubility (1.79 ppb). 

Similarly, the 1-in-10 year peak concentration of metaflumizone predicted in the water column for 

residential (0.021 ppb for the Baton Rouge, LA scenario) uses is approximately 1% of the aqueous 

solubility limit. Therefore, even if all acute toxic effects to water column-dwelling invertebrates, water 

column dwelling and benthic fish, and aquatic vascular plants are assumed to occur at the limit of 

solubility, then the maximum acute RQ for all aquatic organisms exposed to metaflumizone solely 

through the water column would be less than the acute endangered species LOC (0.05 for animals and 1 

for plants). In addition, chronic tests that were submitted with estuarine/marine fish and freshwater 

invertebrates did not show any signs of toxicity at or below the 1-in-10 year peak concentration from 

PRZM/EXAMS (0.019 ppb). Therefore, acute and chronic risks to fish, invertebrates and aquatic 

plants are not expected due to exposure from metaflumizone freely-dissolved in water. Although 

dietary exposure is a significant source of exposure to aquatic organisms (i.e., 1 to 1.5X exposure via the 

water column; Appendix F), it would not likely result in exposures that exceed the LOC.

With regard to potential risk to benthic invertebrates via sediment and sediment pore water exposure, 

results from the PRZM/EXAMS modeling (Table 1) indicate that maximum peak EECs in bulk sediment 

(14 mg/kg d.w.) and pore water (0.007 ppb) are about well below the lowest toxicity reference values 

obtained for benthic invertebrates (> 935 mg/kg d.w. and >1,700 ppb, respectively, for the estuarine 
11

amphipod, Leptocheirus plumulosus; Table C-2 of Appendix C). Therefore, risks to benthic 

invertebrates are not expected via exposure to metaflumizone in sediments.

IV. REFERENCES

Allen, C.R., Willey, R.D., Myers, P.E., Horton, P.M., and Buffa, J. 2000. Impact of red imported fire ant 

infestation on northern bobwhite quail abundance trends in southeastern United States. Journal of 

Agricultural and Urban Entomology. 17: 43-51.

Allen, C.R., Epperson, D.M, and Garmestani, A.S. 2004. Red imported fire ant impacts on wildlife: A 

decade of research. American Midland Naturalist. 152: 88-103.

Arnot, J. and Gobas, F. 2004. A Food Web Bioaccumulation Model For Organic Chemicals In Aquatic 

Ecosystems. Environmental Toxicology and Chemistry. 23: 2343-2355.

Kopachena, J.G., Buckley, A.J., and Potts, G.A. 2000. Effects of the red imported fire ant (Solenopsis 

invicta) on reproductive success of barn swallows (Hirundo rustica) in northeast Texas 

Southwestern Naturalist. 45: 477-482.

Lechner, K.A., Ribble, D.O. 1996. Behavioral interactions between red imported fire ants (Solenopsis 

invicta) and three rodent species of south Texas. Southwestern Naturalist. 41: 123-128.

Mackay, D. And S. Paterson. 1981. Calculating fugacity. Environ. Sci. Technol. 15: 1006-1014.

MRID 46264315. Schneider, S.; Deckardt, K.; Hellwig, J.; et. al.; (2004) BAS 320 I - Two-Generation 

Reproduction Toxicity Study in Wistar Rats Oral Administration (Gavage): Final Report. Project 

Number: 73R0071/01058, 2004/1009123. Unpublished study prepared by BASF 

Aktiengesellschaft. 1129 p. 

MRID 46264428. Gallagher, S.; Grimes, J.; Beavers, J.; et. al.; (2003) Avian Dietary Toxicity Test with 

BAS 320 I in the Northern Mallard Duck (Anas platyrhynchos): Final Report. Project Number: 

1131/05, 147/206, 2003/5000290. Unpublished study prepared by Wildlife International, Ltd. 80 

p. 

MRID 46264430. Zok, S. (2004) BAS 320 I - 1-Generation Reproduction Study on the Bobwhite Quail 

(Colinus virginianus) by Administration in the Diet: Final Report. Project Number: 

Table 1. Maximum 1 in 10 years EECs in compartments of the aquatic environment based 

on 4 bait applications at a rate of 0.00095 lb a.i/A under a 28-day reapplication interval(1). 

Aquatic Compartment Peak 96 hr 21 Day 60 Day 90 Day Yearly

Agricultural Uses

Water Column (1) (ug/L) 0.0187 0.0124 0.0094 0.0092 0.0091 0.0090

Benthic Pore Water (ug/L) 0.0072 0.0072 0.0072 0.0072 0.0072 0.0071

Benthic Sediment (mg/kg dry wt) 14.37 14.37 14.36 14.36 14.35 14.11

Residential Uses

Water Column (2) (ug/L) 0.021 0.018 0.015 0.015 0.015 0.021

(1) EECs are from the S. Texas Grapefruit agricultural exposure scenario

(2) EECs are from the Baton Rouge, LA residential exposure scenario
12

71W0071/015111, 2004/1003988, 2004/1004399. Unpublished study prepared by BASF 

Aktiengesellschaft. 425 p. 

MRID 46264539. Hughes, C.; Holmes, C. (2004) Toxicity of BAS 320 00I to the Unicellular Green 

Alga, Selenastrum capricornutum: Final Report. Project Number: 85681, 48598, 2004/5000073. 

Unpublished study prepared by Analytical Bio-Chemistry Labs., Inc and BASF 

Aktiengesellschaft. 45 p. 

Pedersen, E.K., Bedford, T.L., Grant, W.E., Vinson, S.B., Martin, J.B., Longnecker, M.T., Barr, C.L., and 

Drees, B.M. 2003. Effect of red imported fire ants on habitat use by hispid cotton rats (Sigmodon 

hispidus) and northern pygmy mice (Baiomys taylori). Southwestern Naturalist. 48: 419-426.

Trapp, S. And J.C McFarlane (eds.). 1995. Plant Contamination Modeling and Simulation of Organic 

Chemical Processes. Lewis Publishers. Boca Raton, Florida.

U.S. EPA. 1992. Comparative analysis of acute avian risk from granular pesticides. Office of Pesticide 

Programs. U.S. EPA. March 1992. 

U.S. EPA. 2004. U.S. Environmental Protection Agency. Overview of the Ecological Risk Assessment 

Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency: Endangered 

and Threatened Species Effects Determinations. Office of Prevention, Pesticide, and Toxic 

Substances. January 23.
13

APPENDIX A. Calculations for Determining Risk to Terrestrial Organisms

Resulting from Direct Consumption of Metaflumizone Fire Ant Bait Granules

A. Avian Risk: Calculations and Results Based on the Acute Dietary Toxicity Endpoint

To exceed the acute risk to listed (endangered) species LOC for birds of 0.1, an EEC of >15.6 mg ai/kgdiet would be required if the most sensitive LC50 value is >156 mg ai/kg diet (MRID 46264315; 

Appendix C).

. 

>156 mg ai/kg diet * 0.1 = >15.6 mg ai/kg-diet

If a 20g bird consumes 0.0228 kilograms of food per day (as estimated in T-REX v 1.4.1; USEPA 2008), 

then 0.3557 milligrams of the diet has to be active ingredient to achieve the EEC of 15.6 mg ai/kg-diet for 

acute risk to listed species.

0.0228 kg diet* 15.6 mg ai/kg diet = 0.3557 mg ai

If there are 667 granules in one gram (as suggested by the registrant in “Comments on the Realism of 

EPA’s Analysis of the Avian Risk of Metaflumizone Fire Ant Bait”), then each granule weighs 1.5 mg.

1 gram ÷ 667 granules = 0.0015g

Based on a percent ai for the formulated product of 0.063%, there is 0.000944528 mg ai in a single 

granule.

0.00063*1.5 mg = 0.000944528 mg ai in a single granule

Based on the following equation, 377 granules would have to be consumed by a 20g bird in a day to 

achieve the EEC of 15.6 mg ai/kg-diet:

The amount of ai to be consumed in a given day in order to trigger endangered species concerns ÷ the 

amount of ai in a single granule =

0.3557 milligrams ai ÷ 0.000944528 mg ai in a granule = 377 granules

Assuming that a bird can identify, walk to, and consume a granule every 5 seconds (as suggested by the 

registrant in “Comments on the Realism of EPA’s Analysis of the Avian Risk of Metaflumizone Fire Ant 

Bait”), it would take ~31 minutes of continuous feeding on granules for a 20 gram bird to consume 377 

granules.

(377 granules * 5 seconds) ÷ 60 seconds/minute = 31.4 minutes

The fire ant bait is to be applied at a rate of 1.5 lb bait per acre. Converting to grams,

1.5 lb * 454 grams/lb = 681 grams of granulated product/acre

Because 667 granules weigh one gram,

667 granules/gram * 681 grams of granules/acre = 454,227 granules applied per acre
14

Converting to granules per square foot:

454,227 granules/acre ÷ 43,560 square feet/acre = 10.4 granules/square foot

Thus, a 20g bird would have to completely glean (100% feeding efficiency) approximately 36 square feet 

to reach a dietary EEC 15.6 mg ai/kg diet to trigger endangered species concerns:

377 granules ÷ 10.4 granules/square foot = 36.2 square feet

If we assume a 50% and 10% feeding efficiency, a 20g bird would have to cover approximately 72.4 and 

362.1 square feet, respectively:

377 granules ÷ 5.2 granules/square foot = 72.4 square feet

377 granules ÷ 1.04 granules/square foot = 362.1 square feet

However, in addition to broadcast treatments, the fire ant bait can also be applied to at rate up to 2oz per 

mound. Converting to grams,

2oz/mound * 28.3 grams/oz = 56.6 grams of granules/mound

Because 667 granules weigh one gram,

667 granules/gram * 56.6 grams of granules/mound = 37,752 granules applied per mound

Thus, a 20g bird would only have to go to one mound and eat approximately 1% of the applied granules 

at that mound to reach an EEC of >15.6 mg ai/kg diet to trigger endangered species concerns:

377 granules ÷ 37,752 granules/mound = 0.00997 mound 

This same analysis can be applied using the acute risk and acute restricted use LOCs of 0.2 and 0.5, 

respectively. Following the same series of calculations, the results described in Table A-1 below can be 

obtained.

Table A-1. Estimates of the number of granules, area foraged, and process time needed for a 20g bird to achieve the dietary 

EEC that would trigger an exceedance of the acute risk (0.1), acute restricted use (0.2), and acute endangered species (0.5) 

level of concern (LOC).

U.S. EPA’s Levels of Concern 

(LOC)

0.1 0.2 0.5

EEC Required to Reach the Specified LOC (mg ai / kg diet) 15.6 31.2 78

# Consumed Granules Required to Reach the Specified LOC 377 753 1883

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 36 ft2

72 ft2181 ft2

Assuming a 50% Feeding Efficiency 72 ft2145 362 ft2

Assuming a 10% Feeding Efficiency 362 ft2

724 ft21810 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 1.0% 2.0% 5.0%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 31 min 63 min 157 min

Likewise, the same analyses can be performed for 100g and 1000g birds. Following the same series of 

calculations, the results described in Table A-2 and A-3 below can be obtained for 100g and 1000g birds, 

respectively.
15

Table A-2. Estimates of the number of granules, area foraged, and process time needed for a 100g bird to achieve the dietary 

EEC that would trigger an exceedance of the acute risk (0.1), acute restricted use (0.2), and acute endangered species (0.5) 

level of concern (LOC).

U.S. EPA’s Levels of Concern 

(LOC)

0.1 0.2 0.5

EEC Required to Reach the Specified LOC (mg ai / kg diet) 15.6 31.2 78

# Consumed Granules Required to Reach the Specified LOC 1074 2147 5368

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 103 ft2

206 ft2516 ft2

Assuming a 50% Feeding Efficiency 206 ft2

413 ft21032 ft2

Assuming a 10% Feeding Efficiency 1032 ft2

2065 ft25161 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 2.8% 5.7% 14.2%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (hours) 1.5 hr 3.0 hr 7.5 hr

Table A-3. Estimates of the number of granules, area foraged, and process time needed for a 1000g bird to achieve the dietary 

EEC that would trigger an exceedance of the acute risk (0.1), acute restricted use (0.2), and acute endangered species (0.5) 

level of concern (LOC).

U.S. EPA’s Levels of Concern 

(LOC)

0.1 0.2 0.5

EEC Required to Reach the Specified LOC (mg ai / kg diet) 15.6 31.2 78

# Consumed Granules Required to Reach the Specified LOC 4790 9579 23948

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 461 ft2

921 ft22303 ft2

Assuming a 50% Feeding Efficiency 921 ft2

1842 ft24605 ft2

Assuming a 10% Feeding Efficiency 4605 ft2

9211 ft223027 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 12.7% 25.4% 63.4%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (hours) 6.7hr 13.3 hr 33.3 hr

B. Avian Risk: Calculations and Results Based on the Estimated Median Lethal Dose

Equivalents Endpoint

EFED has estimated median lethal dose equivalents from diet based on the LC50 value of >156 mg ai/kgdiet (MRID 46264315; Appendix C) and the data on food consumption and average body weight from 

the acute dietary study with mallard ducks. The estimated median lethal dose equivalents from diet, in 

addition to the LC50 value, was considered because it is body-weight specific and can provide scaling of 

feeding and toxicity to various sizes of birds. In the available acute study with mallards, the average daily 

food consumption and average body weight of birds in the 156 mg ai/kg-diet treatment group was 0.096 

kg/bird and 0.203 kg, respectively. The median lethal dose equivalent from diet is calculated as follows:

(156 mg ai/kg-diet * 0.096 kg diet) ÷ 0.203 kg bw = 73.8 mg ai /kg-bw

This estimated median lethal dose equivalents from diet can be adjusted for a 20g bird:

Adj LD LD

AW

TW

x

.

( )

50 50

1

















where:
16

Adj. LD50 = adjusted LD50 (mg/kg-bw) calculated by the equation

LD50 = endpoint reported from bird study (mg/kg-bw)= 73.8 mg ai /kg-bw

TW = body weight of tested animal= 0.203 kg. 

AW = body weight of assessed animal= 0.02 kg

x = Mineau scaling factor for birds; EFED default 1.15

The adjusted estimated median lethal dose equivalents from diet value for 20g birds is 52.1 mg ai /kg-bw.

To exceed the endangered species LOC of 0.1, the EEC equivalent dose has to equal 5.21 mg ai /kg-bw:

52.1 mg ai / kg-bw *0.1= 5.21 mg ai / kg-bw

If there are 667 granules in one gram, then each granule weighs 1.5 mg.

1 gram ÷ 667 granules = 0.0015g

Based on a percent active ingredient for the formulated product of 0.063%, there is 0.000944528 mg ai in 

a single granule.

0.00063*1.5 mg = 0.000944528 mg ai in a single granule

Therefore, if a 20g bird eats one granule, the dose is 0.047226387 mg ai/kg-bw.

0.000944528 mg ai ÷ 0.020 kg-bw = 0.047226387 mg ai/kg-bw

Subsequently, a 20g bird must eat approximately 110 granules to reach an EEC equivalent dose of 5.21 

mg ai/kg-bw to trigger endangered species concerns.

0.047226387 mg ai/kg bw * 110 granules = 5.21 mg ai/kg-bw

As we did before, we can assume that a bird can identify, walk to, and consume a granule every 5 

seconds. Therefore, based on this analysis, it would take ~9.2 minutes of continuous feeding on granules 

for a 20 gram bird to consume 110 granules. 

(110 granules * 5 seconds) ÷ 60 seconds/minute = 9.2 minutes

The fire ant bait is to be applied at a rate of 1.5 lb bait per acre. Converting to grams,

1.5 lb * 454 grams/lb = 681 grams of granules/acre

Because 667 granules weigh one gram,

667 granules/gram * 681 grams of granules/acre = 454,227 granules applied per acre

Converting to granules per square foot:

454,227 granules/acre ÷ 43,560 square feet/acre = 10.4 granules/square foot

Thus, a 20g bird would have to completely glean (100% feeding efficiency) approximately 10.6 square 

feet to reach an EEC equivalent dose of 5.21 mg ai/kg bw to trigger endangered species concerns:
17

110 granules ÷ 10.4 granules/square foot = 10.6 square feet

If we assume a 50% and 10% feeding efficiency, a 20g bird would have to cover approximately 29 and 

146 square feet, respectively:

110 granules ÷ 5.2 granules/square foot = 21.2 square feet

110 granules ÷ 1.04 granules/square foot = 105.8 square feet

The fire ant bait can also be applied to at rate up to 2oz per mound. Converting to grams,

2oz/mound * 28.3 grams/oz = 56.6 grams of granules/mound

Because 667 granules weigh one gram,

667 granules/gram * 56.6 grams of granules/mound = 37,752 granules applied per mound

Thus, a 20g bird would only have to go to one mound and eat approximately 0.3% of the applied 

granules at that mound to reach an EEC equivalent dose of 5.21 mg ai/kg bw to trigger endangered 

species concerns:

110 granules ÷ 37,752 granules/mound = 0.003 mound 

This same analysis can be applied using the acute risk and acute restricted use LOCs of 0.02 and 0.5, 

respectively. Following the same series of calculations, the results described in Table A-4 below can be 

obtained.

Table A-4. Estimates of the number of granules, area foraged, and process time needed for a 20g bird to achieve the EEC 

equivalent dose that would trigger an exceedance of the acute risk (0.1), acute restricted use (0.2), and acute endangered 

species (0.5) level of concern (LOC).

U.S. EPA’s Levels of Concern 

(LOC)

0.1 0.2 0.5

EEC Equivalent Dose Required to Reach the Specified LOC (mg ai / kg-bw) 5.21 10.4 26.1

# Consumed Granules Required to Reach the Specified LOC 110 221 552

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 11 ft2

21 ft253 ft2

Assuming a 50% Feeding Efficiency 21 ft2

42 ft2106 ft2

Assuming a 10% Feeding Efficiency 106 ft2

212 ft2531 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 0.3% 0.6% 1.5%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 9 min 18 min 46 min

Likewise, the same analyses can be performed for 100g and 1000g birds. Following the same series of 

calculations, the results described in Table A-5 and A-6 below can be obtained for 100g and 1000g birds, 

respectively.

Table A-5. Estimates of the number of granules, area foraged, and process time needed for a 100g 

bird to achieve the EEC equivalent dose that would trigger an exceedance of the acute risk (0.1), 

acute restricted use (0.2), and acute endangered species (0.5) level of concern (LOC).

U.S. EPA’s Levels of Concern 

(LOC)

0.1 0.2 0.5

EEC Equivalent Dose Required to Reach the Specified LOC (mg ai / kg-bw) 6.6 13.3 33.2

# Consumed Granules Required to Reach the Specified LOC 703 1405 3513
18

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 68 ft2

135 ft2338 ft2

Assuming a 50% Feeding Efficiency 135 ft2

270 ft2676 ft2

Assuming a 10% Feeding Efficiency 676 ft2

1351 ft23378 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 1.9% 3.7% 9.3%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (hours) 1 hr 2 hr 5 hr

Table A-6. Estimates of the number of granules, area foraged, and process time needed for a 1000g 

bird to achieve the EEC equivalent dose that would trigger an exceedance of the acute risk (0.1), 

acute restricted use (0.2), and acute endangered species (0.5) level of concern (LOC).

U.S. EPA’s Levels of Concern 

(LOC)

0.1 0.2 0.5

EEC Equivalent Dose Required to Reach the Specified LOC (mg ai / kg-bw) 9.4 18.7 46.9

# Consumed Granules Required to Reach the Specified LOC 9925 19849 49623

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 954 ft2

1909 ft24771 ft2

Assuming a 50% Feeding Efficiency 1909 ft2

3817 ft29543 ft2

Assuming a 10% Feeding Efficiency 9543 ft2

19086 ft247715 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 26.3% 52.6% 131.4%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (hours) 14 hr 28 hr 69 hr

C. Avian Risk: Calculations and Results Based on the Chronic Dietary Toxicity Endpoint

To exceed the chronic risk LOC for birds of 1.0, an EEC of 7.6 mg ai/kg-diet would be required if the 

most sensitive NOAEC value is 7.6 mg ai/kg diet. 

If a 20g bird consumes 0.0228 kilograms of food per day (as estimated in T-REX v 1.4.1; USEPA 2008), 

then 0.1733 milligrams of the diet has to be active ingredient to achieve the EEC of 7.6 mg ai/kg-diet 

0.0228 kg diet* 7.6 mg ai/kg diet = 0.1733 mg ai

If there are 667 granules in one gram, then each granule weighs 1.5 mg.

1 gram ÷ 667 granules = 0.0015g

Based on a percent ai for the formulated product of 0.063%, there is 0.000944528 mg ai in a single 

granule.

0.00063*1.5 mg = 0.000944528 mg ai in a single granule

Based on the following equation, 183 granules would have to be consumed by a 20g bird in a day to 

achieve the EEC of 7.6 mg ai/kg-diet:

The amount of ai to be consumed in a given day in order to trigger endangered species concerns ÷ the 

amount of ai in a single granule =

0.1733 milligrams ai ÷ 0.000944528 mg ai in a granule = 183 granules

Assuming that a bird can identify, walk to, and consume a granule every 5 seconds (as suggested by 

BASF), it would take ~15 minutes of continuous feeding on granules for a 20 gram bird to consume 183 

granules.
19

(183 granules * 5 seconds) ÷ 60 seconds/minute = 15.3 minutes

The fire ant bait is to be applied at a rate of 1.5 lb bait per acre. Converting to grams,

1.5 lb * 454 grams/lb = 681 grams of granules/acre

Because 667 granules weigh one gram,

667 granules/gram * 681 grams of granules/acre = 454,227 granules applied per acre

Converting to granules per square foot:

454,227 granules/acre ÷ 43,560 square feet/acre = 10.4 granules/square foot

Thus, a 20g bird would have to completely glean (100% feeding efficiency) approximately 18 square feet 

to reach a dietary EEC 7.6 mg ai/kg diet to trigger endangered species concerns:

183 granules ÷ 10.4 granules/square foot = 17.6 square feet

If we assume a 50% and 10% feeding efficiency, a 20g bird would have to cover approximately 35 and 

176 square feet, respectively:

183 granules ÷ 5.2 granules/square foot = 35.3 square feet

183 granules ÷ 1.04 granules/square foot = 176.4 square feet

However, in addition to broadcast treatments, the fire ant bait can also be applied to at rate up to 2oz per 

mound. Converting to grams,

2oz/mound * 28.3 grams/oz = 56.6 grams of granules/mound

Because 667 granules weigh one gram,

667 granules/gram * 56.6 grams of granules/mound = 37,752 granules applied per mound

Thus, a 20g bird would only have to go to one mound and eat approximately 0.5% of the applied granules 

at that mound to reach an EEC of 7.6 mg ai/kg diet to trigger endangered species concerns:

183 granules ÷ 37,752 granules/mound = 0.00485 mound 

Likewise, the same analyses can be performed for 100g and 1000g birds. Following the same series of 

calculations, the results described in Table A-7 below can be obtained for 100g and 1000g birds. 

Following the same series of calculations but based on a LOAEC of mg ai/kg diet, the results described in 

Table A-8 below can be obtained.

Table A-7. Estimates of the number of granules, area foraged, and process time needed for a 20g, 

100g, and 1000g bird to achieve the dietary EEC that would trigger an exceedance of the chronic risk 

(1.0) level of concern (LOC) based on a NOAEC of 7.6 mg ai/kg diet.

Bird Size (grams)

20 100 1000

EEC Required to Reach the chronic risk LOC of 1.0 (mg ai / kg diet) 7.6 7.6 7.6
20

# Consumed Granules Required to Reach the Specified LOC 183 523 2333

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 18 ft2

50 ft2224 ft2

Assuming a 50% Feeding Efficiency 35 ft2

101 ft2449 ft2

Assuming a 10% Feeding Efficiency 176 ft2

503 ft22244 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 0.5% 1.4% 6.2%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 15 min 44 min 194 min

Table A-8. Estimates of the number of granules, area foraged, and process time needed for a 20g, 

100g, and 1000g bird to achieve the dietary EEC that would trigger an exceedance of the chronic 

risk (1.0) level of concern (LOC) based on a LOAEC of 15 mg ai/kg diet.

Bird Size (grams)

20 100 1000

EEC Required to Reach the chronic risk LOC of 1.0 (mg ai / kg diet) 15 15 15

# Consumed Granules Required to Reach the Specified LOC 362 1032 4605

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 35 ft2

99 ft2443 ft2

Assuming a 50% Feeding Efficiency 70 ft2

199 ft2886 ft2

Assuming a 10% Feeding Efficiency 348 ft2

993 ft24428 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 1.0% 2.7% 12.2%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 30 min 86 min 384 min

D. Mammalian Risk: Calculations and Results Based on the Chronic Dietary Toxicity

Endpoint

To exceed the chronic risk LOC for mammals of 1.0, an EEC of 400 mg ai/kg-diet would be required if 

the most sensitive NOAEC value is 400 mg ai/kg diet. 

If a 15g mammal consumes 0.00318 kilograms of food per day (as estimated in T-REX v 1.4.1 for 

grainivores; USEPA 2008), then 1.272 milligrams of the diet has to be active ingredient to achieve the 

EEC of 400 mg ai/kg-diet 

0.00318 kg diet* 400 mg ai/kg diet = 1.272 mg ai

If there are 667 granules in one gram, then each granule weighs 1.5 mg.

1 gram ÷ 667 granules = 0.0015g

Based on a percent ai for the formulated product of 0.063%, there is 0.000944528 mg ai in a single 

granule.

0.00063*1.5 mg = 0.000944528 mg ai in a single granule

Based on the following equation, 1347 granules would have to be consumed by a 15g mammal in a day to 

achieve the EEC of 400 mg ai/kg-diet:

The amount of ai to be consumed in a given day in order to trigger endangered species concerns ÷ the 

amount of ai in a single granule =

1.272 milligrams ai ÷ 0.000944528 mg ai in a granule = 1347 granules
21

Using the same assumption as for birds (a mammal can identify, walk to, and consume a granule every 5 

seconds), it would take ~112 minutes of continuous feeding on granules for a 15 gram mammal to 

consume 1347 granules.

(1347 granules * 5 seconds) ÷ 60 seconds/minute = 112.3 minutes

The fire ant bait is to be applied at a rate of 1.5 lb bait per acre. Converting to grams,

1.5 lb * 454 grams/lb = 681 grams of granules/acre

Because 667 granules weigh one gram,

667 granules/gram * 681 grams of granules/acre = 454,227 granules applied per acre

Converting to granules per square foot:

454,227 granules/acre ÷ 43,560 square feet/acre = 10.4 granules/square foot

Thus, a 15g mammal would have to completely glean (100% feeding efficiency) approximately 129.5 

square feet to reach a dietary EEC 400 mg ai/kg diet to trigger endangered species concerns:

1347 granules ÷ 10.4 granules/square foot = 129.5 square feet

If we assume a 50% and 10% feeding efficiency, a 15g mammal would have to cover approximately 259 

and 1295 square feet, respectively:

1347 granules ÷ 5.2 granules/square foot = 259 square feet

1347 granules ÷ 1.04 granules/square foot = 1295.2 square feet

However, in addition to broadcast treatments, the fire ant bait can also be applied to at rate up to 2oz per 

mound. Converting to grams,

2oz/mound * 28.3 grams/oz = 56.6 grams of granules/mound

Because 667 granules weigh one gram,

667 granules/gram * 56.6 grams of granules/mound = 37,752 granules applied per mound

Thus, a 15g mammal would only have to go to one mound and eat approximately 3.6% of the applied 

granules at that mound to reach an EEC of 7.6 mg ai/kg diet to trigger endangered species concerns:

1347 granules ÷ 37,752 granules/mound = 0.0357 mound 

Likewise, the same analyses can be performed for 35g and 1000g mammals. Following the same series 

of calculations, the results described in Table A-9 below can be obtained for 35g and 1000g mammals. 

Following the same series of calculations but based on a LOAEC of 1000 mg ai/kg diet, the results 

described in Table A-10 below can be obtained.

Table A-9. Estimates of the number of granules, area foraged, and process time needed for a 15g, 

35g, and 1000g mammal to achieve the dietary EEC that would trigger an exceedance of the chronic 

risk (1.0) level of concern (LOC) based on a NOAEC of 400 mg ai/kg diet.
22

Mammal Size (grams)

15 35 1000

EEC Required to Reach the chronic risk LOC of 1.0 (mg ai / kg diet) 400 400 400

# Consumed Granules Required to Reach the Specified LOC 1347 2173 14399

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 130 ft2

209 ft21384 ft2

Assuming a 50% Feeding Efficiency 259 ft2

418 ft22769 ft2

Assuming a 10% Feeding Efficiency 1295 ft2

2089 ft213844 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 3.6% 5.8% 38.1%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 112 min 181 min 1200 min

Table A-10. Estimates of the number of granules, area foraged, and process time needed for a 15g, 

35g, and 1000g mammal to achieve the dietary EEC that would trigger an exceedance of the chronic 

risk (1.0) level of concern (LOC) based on a LOAEC of 1000 mg ai/kg diet.

Bird Size (grams)

15 35 1000

EEC Required to Reach the chronic risk LOC of 1.0 (mg ai / kg diet) 1000 1000 1000

# Consumed Granules Required to Reach the Specified LOC 3367 5431 35997

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 324 ft2

522 ft23461 ft2

Assuming a 50% Feeding Efficiency 647 ft2

1044 ft26922 ft2

Assuming a 10% Feeding Efficiency 3237 ft2

5222 ft234612 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 8.9% 14.4% 95.4%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 281 min 453 min 3000 min

E. Mammalian Risk: Calculations and Results Based on the Chronic Dose-Based Toxicity 

Endpoint

The most sensitive chronic NOAEL of 20 mg ai/kg-bw/day from the available reproduction studies with 

rats (MRID 46264315, Appendix C) is also considered because it is body-weight specific and can 

provide scaling of feeding and toxicity to various sizes of mammals. This most sensitive chronic NOAEL 

can be adjusted to account for varying size classes of mammals according to the following equation:

Adjusted NOAEL = NOAEL (TW/AW)(0.25)

where:

TW = body weight of tested animal (350 g rat); and

AW = body weight of assessed animal (15, 35, and 1000 g to account for 3 different size classes).

The adjusted estimated median lethal dose equivalents from diet value for 15g mammals is 43.96 mg ai 

/kg-bw/day.

To exceed the chronic risk LOC of 1, the EEC equivalent dose has to equal 43.96 mg ai /kg-bw:

43.96 mg ai / kg-bw *1= 43.96 mg ai / kg-bw

If there are 667 granules in one gram, then each granule weighs 1.5 mg.

1 gram ÷ 667 granules = 0.0015g
23

Based on a percent active ingredient for the formulated product of 0.063%, there is 0.000944528 mg ai in 

a single granule.

0.00063*1.5 mg = 0.000944528 mg ai in a single granule

Therefore, if a 15g mammal eats one granule, the dose is 0.062968533 mg ai/kg-bw.

0.000944528 mg ai ÷ 0.015 kg-bw = 0.062968533 mg ai/kg-bw

Subsequently, a 15g mammal must eat approximately 698 granules to reach an EEC equivalent dose of 

43.96 mg ai /kg-bw to trigger endangered species concerns.

0.062968533 mg ai/kg bw * 698 granules = 43.96 mg ai /kg-bw

As we did for birds, we can assume that a mammal can identify, walk to, and consume a granule every 5 

seconds. Therefore, based on this analysis, it would take ~58.2 minutes of continuous feeding on 

granules for a 15 gram mammal to consume 698 granules. 

(698 granules * 5 seconds) ÷ 60 seconds/minute = 58.2 minutes

The fire ant bait is to be applied at a rate of 1.5 lb bait per acre. Converting to grams,

1.5 lb * 454 grams/lb = 681 grams of granules/acre

Because 667 granules weigh one gram,

667 granules/gram * 681 grams of granules/acre = 454,227 granules applied per acre

Converting to granules per square foot:

454,227 granules/acre ÷ 43,560 square feet/acre = 10.4 granules/square foot

Thus, a 15g mammal would have to completely glean (100% feeding efficiency) approximately 67.1 

square feet to reach an EEC equivalent dose of 43.96 mg ai/kg bw to trigger endangered species concerns:

698 granules ÷ 10.4 granules/square foot = 67.1 square feet

If we assume a 50% and 10% feeding efficiency, a 15g mammal would have to cover approximately 134 

and 671 square feet, respectively:

698 granules ÷ 5.2 granules/square foot = 134.2 square feet

698 granules ÷ 1.04 granules/square foot = 671.2 square feet

The fire ant bait can also be applied to at rate up to 2oz per mound. Converting to grams,

2oz/mound * 28.3 grams/oz = 56.6 grams of granules/mound

Because 667 granules weigh one gram,

667 granules/gram * 56.6 grams of granules/mound = 37,752 granules applied per mound
24

Thus, a 15g mammal would only have to go to one mound and eat approximately 1.8% of the applied 

granules at that mound to reach an EEC equivalent dose of 43.96 mg ai/kg bw to trigger endangered 

species concerns:

698 granules ÷ 37,752 granules/mound = 0.018 mound 

These same analyses can be performed for 35g and 1000g mammals. Following the same series of 

calculations, the results described in Table A-11 below can be obtained for 35g and 1000g mammals.

Following the same series of calculations but based on a LOAEL of 50 mg ai/kg-bw/day, the results 

described in Table A-12 below can be obtained.

Table A-11. Estimates of the number of granules, area foraged, and process time needed for a 15g, 

35g, and 1000g mammal to achieve the EEC equivalent dose that would trigger an exceedance of the 

chronic risk (1.0) level of concern (LOC) based on a NOAEL of 20 mg ai/kg-bw/day.

Mammal Size (grams)

15 35 1000

EEC Required to Reach the chronic risk LOC of 1.0 (mg ai / kg-bw) 43.96 35.57 15.38

# Consumed Granules Required to Reach the Specified LOC 698 1318 16287

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 67 ft2

127 ft21566 ft2

Assuming a 50% Feeding Efficiency 134 ft2

253 ft23132 ft2

Assuming a 10% Feeding Efficiency 671 ft2

1267 ft215660 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 1.8% 3.5% 43.1%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 58 min 110 min 1357 min

Table A-12. Estimates of the number of granules, area foraged, and process time needed for a 15g, 

35g, and 1000g mammal to achieve the EEC equivalent dose that would trigger an exceedance of the 

chronic risk (1.0) level of concern (LOC) based on a LOAEL of 50 mg ai/kg-bw/day.

Mammal Size (grams)

15 35 1000

EEC Required to Reach the chronic risk LOC of 1.0 (mg ai / kg-bw) 109.89 88.91 38.46

# Consumed Granules Required to Reach the Specified LOC 1745 3295 40717

Area of Field to be Foraged (square feet) to 

Achieve the Specified LOC Based on Application 

Rate of 10.4 granules/square foot

Assuming a 100% Feeding Efficiency 168 ft2

317 ft23915 ft2

Assuming a 50% Feeding Efficiency 336 ft2

634 ft27830 ft2

Assuming a 10% Feeding Efficiency 1678 ft2

3168 ft239151 ft2

% of Granules Applied to One Mound that Need to be Consumed to Reach the specified LOC 4.6% 8.7% 107.9%

Process Time to Consume Granules Assuming a Rate of 1 granule every 5 seconds (minutes) 145 min 275 min 3393 min

F. References

T-REX. 2008. Terrestrial Residue Exposure Model (T-REX), Version 1.4.1 October 9, 2008. 

Environmental Fate and Effects Division, Office of Pesticide Programs, U.S. Environmental 

Protection Agency, Washington, D.C. (available at: 

http://www.epa.gov/oppefed1/models/terrestrial/index.htm)
25

APPENDIX B. Calculations for Determining Risk to Terrestrial Organisms 

Resulting from Consumption of Soil Invertebrates that have Bioaccumulated 

Metaflumizone 

A. Use of fugacity approach to estimate pesticide concentrations in earthworms located on 

treated field

In order to explore the potential exposures of mammals and birds to pesticides in the soil and earthworms 

on the treatment site, a simple fugacity approach can be employed to estimate concentrations of the 

pesticide of interest earthworms. Fugacity is most often regarded as the "escaping tendency" of a 

chemical from a particular phase. Fugacity (F) has units of pressure, generally pascals (Pa), and can be 

related to phase concentrations. For any particular environmental phase (e.g., water, soil, air, or biota) 

there is a corresponding "fugacity capacity" with units of mol/m3-Pa and is denoted by Z. The 

relationship between fugacity, fugacity capacity and chemical concentration (C) is defined by Equation 1.

Fugacity capacities for a given chemical are calculated for the phases of interest as part of the exposure 

point estimation methodology (Mackay and Paterson 1981). The following calculations of fugacity 

capacities for soil (ZS) and earthworms (ZE) (Equations 2 and 3, respectively) require several chemicalspecific parameters and assumptions of system temperature (25oC) and steady state equilibrium. 

Parameter values relevant to Equations 2 and 3 are defined in Table A1.

Fugacity capacities for a given chemical are calculated for the phases of interest as part of the exposure 

point concentration estimation methodology. By definition, the ratio between Z values of different 

phases (compartments) equals the partitioning coefficient (e.g., Equation 4).

In this approach, it is assumed that a pesticide partitions between the soil, the (pore) water and the air 

contained within the soil of the treatment site. It is assumed that earthworms dwelling within the soil are 

exposed to a pesticide via ingestion of contaminated soil. The concentration of a pesticide in earthworm 

tissues can be calculated according to Equation 5 (see Table B-1 for parameter definitions). 

Equation 1. C  Z *F

H

K

Equation Z

d S

S

* 

2. 

H

L K

Equation Z

OW

E

*

3. 

OW

water

oc ol K

Z

Z

Equation 

tan 4.



















S

E

E S

Z

Z

Equation 5. C C *
26

Table B-1. Summary of parameters relevant to earthworm fugacity model.

Symbol Definition Units

CE Chemical concentration in earthworm tissue mol/m3

CE' Chemical concentration in earthworm tissue g/kg

CS Chemical concentration in soil mol/m3

H Henry’s Law constant m

3

-Pa/mol

Kd Soil partitioning coefficient cm3/g

KOW Octanol to water partition coefficient none

L Lipid fraction of earthworm none

MW molecular weight of chemical g/mol

ZE

Fugacity capacity of pesticide in 

earthworms mol/m3

-Pa

ZS Fugacity capacity of pesticide in soil mol/m3-Pa

ρE density of earthworm kg/m3

ρS Bulk density of soil g/cm3

Equation 5 can be redefined using equations 2 and 3 as follows in Equation 6. Equation 6 is used to 

calculate the concentration of a pesticide in earthworms inhabiting the soil of treatment sites.

The resulting CE value is in units of mol/m3. This value is converted to units of g/kg using Equation 7. 

The density of the earthworm (ρE) is assumed to be 1000 kg/m3 (equivalent to density of water). 

B. Calculation of Metaflumizone Soil Concentrations

CS is intended to be representative of the steady-state concentrations of the pesticide of interest in soil. 

Soil concentrations of metaflumizone were calculated based on a depth of 1cm (a chemical concentration 

averaged over a 1-cm soil depth was used to reflect a concentration across the earthworm occupied area 

of soil), the use characterization for metaflumizone when applied via broadcast methods (maximum 

application rate of 0.00095 lb a.i./A, a total of 4 applications, and an 4-week retreatment interval), and a 

1-acre terrestrial environment. The following equation was used to calculate the initial soil concentration 

immediately following the first application:

Equation 8 

where,

Csoil = concentration in soil immediately following a single application (mg/kg)

AR = application rate (=0.00095 lb a.i./acre)

z = soil depth (= 1 cm)

ρsoil = soil bulk density (=1.65 g/cm3)

d s

S ow

E

K

C L K

Equation C

* 

* *

6. 

C

application rate

soil depth soil density

AR CF CF

z CF soil

soili







 

 

1 2

3 

E

E

E

C MW Equation C



*

7.

'


27

CF1 = conversion factor, 453582.4 mg = 1 lb

CF2 = conversion factor, 1 acre = 40468730 cm2

 CF3 = conversion factor, 0.001 kg = 1 g

For metaflumizone, the initial soil concentration immediately following the first application was 

calculated as 0.0065 mg/kg (Figure B-1). However, in order to determine the maximum soil 

concentration under a multiple application scenario with a uniform application rate and interval 

throughout, a measure of dissipation in surface soil (the mean aerobic soil metabolism half-life of 142 

days for metaflumizone used in the PRZM/EXAMS modeling). At the end of the first application 

interval, the soil concentration (just prior to the second application) was determined as: 

Equation 9 C soil @ T1 = e (-k * t)

Csoil @ T1 = the concentration of chemical found in bulk soil at the end of the first 

application (mg/kg) 

t = the time in days (28 d)

k = soil degradation rate constant = calculated assuming first order kinetic based 

on 142-d half life (= 0.00488 d-1) s 

Using equation 9, the calculated concentration of metaflumizone in soil at the end of the first application 

interval was 0.0056 mg/kg (day 28). The concentration of metaflumizone in soil on the second, third and 

fourth application events (days 28, 56, and 84) was then determined by summing the concentrations at the 

end of the prior application interval (Equation 9) with that calculated for an initial application (Equation 

8) and then subjecting the combined concentration to first order degradation kinetics as shown in 

Equation 9. The resulting daily concentration profile for calculated metaflumizone concentrations in soil 

is shown in Figure B-1. These yielded a maximum concentration of metaflumizone in soil of 0.021

mg/kg.

0

0.005

0.01

0.015

0.02

0.025

0 50 100 150 200 250 300 350 400

Time (days)

S

oil C

o

n

c. (m

g/k

g)

0.00095 lb a.i./A x 4 appls x 28d 

interval

Figure B-1. Calculated Daily Concentration of Metaflumizone in Soil

B. Model Input Parameters
28

Input parameters used for estimating the bioaccumulation of metaflumizone in earthworms are shown in 

Table B-2. 

Table B-2. Input parameters used for earthworm bioaccumulation modeling with metaflumizone.

Characteristics of Metaflumizone

Parameter (symbol) Value Units

Pesticide Name Metaflumizone none

Molecular weight (MW) 506.4 g/mol

Octanol-water Partition Coefficient (Kow) 125893 none

Soil partition coefficient (Kd) 615.06 cm3

/g

Soil Parameters

Parameter (symbol) Value Units

Bulk density of soil (ρs) 1.65 g/cm3

Concentration of metaflumizone in soil * 0.035 g/m3

Concentration of Metaflumizone in soil (Cs) 6.93E-05 mol/m3

* based on soil bulk density (1.65 g/cm3) and soil concentration ( 0.024 mg/kg)

Earthworm Parameters

Parameter (symbol) Value Units

Lipid fraction of earthworm (L) 0.01 none

Water fraction of earthworm (W) 0.84 none

Density of earthworm (ρE) 1000 kg/m3

C. Model Outputs

The predicted concentration of metaflumizone in earthworms (in units of mol/m3 and g/kg) is shown in 

Table B-3. This concentration is equivalent to 0.044 mg/kg (wet weight) in earthworms.

Table B-3. Predicted concentration of metaflumizone in earthworms

Parameter (symbol) Value Units

Concentration of Metaflumizone in earthworm (CE) 8.60E-05 mol/m3

Concentration of Metaflumizone in earthworm (CE') 4.35E-05 g/kg*

D. Risk Characterization for Terrestrial Wildlife Risk 

Risks for birds and mammals that consume terrestrial invertebrates as the majority of their diet were 

estimated based on comparison of the concentration of metaflumizone in earthworm tissue (Cearthworm) 

with toxicity values for birds and mammals. A 1-cm soil depth was used to reflect a concentration across 

the earthworm occupied area of soil to derive the Cearthworm. Although earthworms are likely to live at 

lower depths in the soil horizon, a 1-cm depth represents a conservative scenario; if risk is acceptable at 

this depth, it will be acceptable if concentrations are averaged over greater depths. It is important to note 

that this estimation of risk also assumes that 100% of the diet is comprised of terrestrial soil invertebrates. 

1. Insectivorous Birds

Acute and chronic risks for insectivorous birds were estimated by comparing the Cearthworm in ppm by the 
29

avian acute LC50 (>156 ppm) and chronic NOAEC for metaflumizone (7.6 ppm). The estimated 

earthworm residue for insectivorous avian receptors (0.05 ppm) is less than the avian chronic endpoint 

(7.6 ppm) and is less than one-thousandth of the acute toxicity endpoint (>156 ppm) for granular 

metaflumizone applications. 

Dose-based acute RQs can also be derived for birds, and are likely to provide more accurate estimates of 

risk to insectivorous birds because they are based on earthworm residues that are consumed by a bird in a 

given day and adjusted LD50 values for the size of the assessed bird, while the dietary-based RQs use no 

such adjustments to account for feeding behavior and varying size classes.

Earthworm residue concentrations derived based on the dose method are first converted to a daily dose by 

multiplying the dietary Cearthworm (0.05 mg/kg) by the amount of food consumed for a 20g bird normalized 

to body weight((20g = 1424 g/kg-bw/d, Table B-4 and Appendix A). A small (20g) bird was chosen as 

the assessed size class because exposure and subsequent risk quotients are higher compared to larger

sized birds. In addition, the LD50 value (73.8 mg/kg-BW; estimated in Appendix A) is adjusted to 

account for a 20-g bird according to Equation 10:

Equation 10 Adj LD LD

AW

TW

x

.

( )

50 50

1

















where:

Adj. LD50 = adjusted LD50 (mg/kg-bw) calculated by the equation

LD50 = endpoint reported from bird study (mg/kg-bw)= 73.8 mg ai /kg-bw

TW = body weight of tested animal= 0.203 kg. 

AW = body weight of assessed animal= 0.02 kg

x = Mineau scaling factor for birds; EFED default 1.15

Table B-4. Avian toxicity data for Metaflumizone.

Endpoint/Parameter (symbol) Value Units

Acute oral LD50 73.8 mg/kg-bw

Body weight of test animal for LD50* (TW) 203 g

Subacute dietary LC50 156 mg/kg-diet

Chronic NOAEC 7.6 mg/kg-diet

Mineau Scaling Factor** 1.15 none

Body weight of assessed animal (AW) 20 g

Food intake of assessed animal (F) 28.47 g/day

Body weight normalized food intake of assessed animal (FN) 1424 g/kg-bw-day

As shown in Table B-5, the acute dose-based, acute diet-based and chronic diet based RQs for birds are <

0.006, which is well below LOCs for acute risk (0.5), acute restricted use (LOC 0.2), and acute 

endangered species (LOC 0.1).Therefore, acute (dose- and dietary-based) and chronic risks to birds 

associated with ingestion of earthworms that have bioaccumulated metaflumizone granules are not 

expected. 

Table B-5. Avian risk quotients for Metaflumizone.

Endpoint EEC Toxicity Value(1) RQ

Avian, acute, dose-based (mg/kg-bw/d) 0.06 52.1 0.001

Avian, acute, dietary-based (mg/kg-diet) 0.04 156.0 0.0003
30

Avian, chronic, dietary-based (mg/kg-diet) 0.04 7.6 0.006

(1) acute dose-based toxicity value (LD50) adjusted for a 20g bird

2. Insectivorous Mammals

Acute risk to insectivorous mammals that may consume contaminated soil invertebrates could not be 

estimated because definitive acute toxicity values were not available; the LD50 value was set as greater 

than the highest treatment level of metaflumizone and no acute dietary studies with mammals were 

available. However, chronic risks for insectivorous mammals were estimated by considering both dietaryand dose-related exposures and effects. In the dietary method, risks were estimated by comparing the 

Cearthworm by the mammalian chronic NOAEC for metaflumizone (400 ppm). In the dose method, the 

residue concentration in earthworms was converted to a daily oral dose based on the fraction of body 

weight consumed as estimated through mammalian allometric relationships. The dose was then compared 

to the NOAEL (20 mg/kg-BW/day) for mammalian receptors.

Based on the dietary method and the metaflumizone application rate of granular 0.00095 lb ai/A, chronic 

LOCs are not exceeded for insectivorous mammals because the earthworm residue concentration (0.05 

ppm) is less than the NOAEC (400 ppm). However, dose-based RQs are likely to provide more accurate 

estimates of risk to insectivorous mammals because they are based on earthworm residues that are 

consumed by a mammal in a given day and adjusted NOAEL values for the size class of the assessed 

mammal, while the dietary-based RQs use no such adjustments to account for feeding behavior and 

varying size classes.

Earthworm residue concentrations derived based on the dose method are first converted to a daily dose by 

multiplying the dietary Cearthworm amount of food consumed for a 15g mammal normalized to body 

weight((15g = 1192 g/kg-bw/d, Table B-6 and Appendix A). A small (15g) mammal was chosen as the 

assessed size class because exposure and subsequent risk quotients are higher compared to larger sized 

mammals. In addition the NOAEL value (20 mg/kg-BW/day) is adjusted to account for the size class of 

the assessed mammal according to the following equation:

Adjusted NOAEL = NOAEL (TW/AW)(0.25)

where:

TW = body weight of tested animal (350 g rat); and

AW = body weight of assessed animal (15g).

Table B-6. Mammalian toxicity data for Metaflumizone.

Endpoint/Parameter (symbol) Value Units

Acute oral LD50 n/a mg/kg-bw

Body weight of acute test animal* (TW) 350 g

Chronic NOAEL 20 mg/kg-bw

Chronic NOAEC 400 mg/kg-diet

Body weight of chronic test animal* (TW) 350 g

Body weight of assessed animal (AW) 15 g

Food intake of assessed animal (F) 17.9 g/day

Body weight normalized food intake of assessed animal (FN) 1192 g/kg-bw-day
31

As shown in Table B-7, estimated chronic dose and diet-based EECs for insectivorous mammals are well 

below the applicable toxicity values, with resulting RQ values of 0.001 or less. The results of the 

assessment indicate that, when risk for mammals is assessed on the basis of daily ingested dietary dose, 

the accumulation of metaflumizone in earthworms does not, by itself, represent a biologically significant 

pathway for exposure. 

Table B-7. Mammalian risk quotients for Metaflumizone.

Endpoint EEC Toxicity Value(1) RQ

Mammalian, chronic dose-based (mg/kg-bw/d) 0.05 44.0 0.001

Mammalian, chronic dietary-based (mg/kg-diet) 0.04 400.0 0.0001

(1) chronic dose-based toxicity value (NOAEL) are adjusted for a 15g mammal

2. Uncertainties Associated with the Fugacity Model

A number of uncertainties associated with the fugacity model used to estimate metaflumizone 

concentrations in earthworm tissue and subsequent risks to insectivorous terrestrial wildlife include:

• A metaflumizone concentration averaged over a 1-cm soil depth was used to reflect a 

concentration across the earthworm occupied area of soil. It is possible that earthworms 

may be present at deeper soil depths, resulting in a lower concentration of metaflumizone 

in bulk soil and earthworm tissue. However, if risk is acceptable at this depth, it will be 

acceptable if concentrations are averaged over greater depths.

• The fugacity-based model assumes equilibrium partitioning between bulk soil and soil 

pore water. In addition, the model assumes a fixed value for soil density, earthworm 

density, temperature, pore space, organic carbon, and the lipid content of the earthworm. 

Resulting concentrations of metaflumizone in earthworm tissue may be either under- or 

over-estimated depending on the soil type, temperature, and size/lipid content of the 

earthworm, at the time of exposure.

• This assessment considers only one route of exposure (i.e., ingestion of terrestrial 

invertebrates that have bioaccumulated metaflumizone from granules in the soil) for 

insectivorous birds and mammals. In addition, it is assumed that 100% of the diet is 

comprised of terrestrial soil invertebrates. Given species-specific feeding habits and 

dietary requirements, this assumption may overestimate risks associated with ingestion of 

soil invertebrates that have accumulated metaflumizone. Other potential routes of 

exposure including direct ingestion of granules, ingestion of granules that adhere to soil 

invertebrates, partitioning of dissolved metaflumizone to sources of wildlife drinking 

water, and dermal exposure of granules released to surrounding soil and puddles or 

combined routes of exposure were not considered. 

References:

Cobb, G.P., E.H. Hol, P.W. Allen, J.A Gagne, R.J. Kendall. 1995. Uptake, metabolism, and toxicity of 

terbufos in the earthworm (Lumbricus terrestris) exposed to COUNTER-15G in artificial soils. Environ. 

Toxicol. Chem. 14(2):279-285.

Mackay, D. and S. Paterson. 1981. Calculating fugacity. Environ. Sci. Technol. 15: 1006-1014.
32

USEPA. 2008. User’s Guide: T-REX Version 1.4.1 (Terrestrial Residue Exposure model). United States 

Environmental Protection Agency. Environmental Fate and Effects Division.
33

APPENDIX C. Summary of Available Toxicity Data for Metaflumizone

Table 1. Toxicity reference values for terrestrial organisms exposed to the metaflumizone. 

Exposure % Active Ingredient Species Toxicity 

Reference Value

Reference

Mammals

Acute (Single oral dose) TGAI (96.3% a.i.; MRID 46264232 & 

MRID 46264234)

TEP (21.97% a.i.; MRID 46264528)

M320I02 (Z-isomer; 96.9% a.i.; 

MRID 46264231)

M320I23 (98.7% a.i.; MRID 

46264233)

Laboratory Rat 

(Rattus norvegicus) and 

Laboratory Mice (Mus 

musculus)

None used. All mammals in every 

acute study submitted survived and 

gained weight throughout each 

study.

MRID’s

46264528

46264231

46264232

46264233

46264234

All Acceptable

Chronic (2-Generation 

repro study (gavage)) 

TGAI

(96.9% a.i.)

Laboratory Rat (Rattus 

norvegicus)

NOAEL = 20 mg a.i./kg bw/day 

NOAEC = 400 ppm

LOAEL = 50 mg a.i./kg bw/day

LOAEC = 1000 ppm

MRID 46264315

Acceptable

Birds

Acute (Single oral dose) TGAI

(96.3% a.i.)

Northern bobwhite quail 

(Colinus virginianus) 

Mallard duck (Anas 

platyrhynchos)

None used. All birds in every acute 

oral toxicity study submitted 

survived without any sub-lethal 

effects observed.

MRID’s 46264425 

46264426

Both Acceptable

Acute (5-Day dietary) TGAI (96.9% a.i.) Mallard duck (Anas 

platyrhynchos)

LC50 >156 ppm a.i. The probit, 

binomial, and moving average

methods could not reliably generate

sound LC50, 95% C.I., and slope 

estimates due to the nonconcentration response pattern of 

mortality. There was 0, 0, 70, 40, 

30, 50, and 90% mortality after 11 

days in the control and 156, 309, 

638, 1228, 2538, and 4999 mg 

a.i./kg-diet treatment groups, 

respectively

MRID 46264428

Supplemental 

Chronic (Avian 

reproduction study 

(dietary exposure))

TGAI (96.9% a.i.) Bobwhite quail

(Colinus Virginianus)

NOAEC = 7.6 ppm 

LOAEC = 15 ppm 

MRID 46264430

Acceptable

Terrestrial Insects

Acute (96-Hour acute 

contact and oral toxicity 

test a)

TGAI (96.3% a.i.) Honey bee

(Apis mellifera)

Contact toxicity

LD50 = 1.65 μg a.i./bee

95% C.I.: 1.39-1.93

Slope:3.64 (2.68-4.59)

Oral toxicity

LD50 = 2.44 μg a.i./bee

95% C.I.: 2.Slope: 2.65 (1.98-3.32)

MRID 46264516

Contact toxicity 

test:

Acceptable

Oral toxicity test:

Supplemental 

Acute (48-Hour acute 

contact toxicity test)

TEP (21.97% a.i.) Parasitic wasps

(Aphidius rhopalosiphi)

LD50 = 0.0012 lb a.i./A

95% C.I.: 0.00028-0.0016

Slope: not applicable w/ binomial 

test

MRID 46499502

Supplemental 

Chronic (40-day 

Reproduction Study)

TEP (22% a.i.) Parasitic wasps

(Aphidius rhopalosiphi)

NOAEC< 0.03 lb a.i./A MRID 46623338

NR b

Earthworms
34

Table 1. Toxicity reference values for terrestrial organisms exposed to the metaflumizone. 

Exposure % Active Ingredient Species Toxicity 

Reference Value

Reference

Acute (14-Day 

Subchronic Toxicity 

Test)

M320I29 (99.9% a.i.) Earthworm (Eisenia fetida) LC50 = 43.62 mg a.i./kg soil

95% C.I.: 39.91-47.33

Slope not reported

NOAEC = 17.1 mg a.i./kg soil

LOAEC = 30.9 mg a.i./kg soil

MRID 46623332

NR b

Chronic (56-Day 

Chronic Toxicity Test)

TEP (21.97% a.i.; MRID 46623328)

M320I23 (98.7% a.i.; MRID 

46623333)

Earthworm (Eisenia fetida) None used. No significant 

treatment-related adverse effects on 

mortality, growth, reproduction or 

feeding activity up to the highest 

concentrations tested.

MRID 46623328

MRID 46623333

NR b

Plants - Tier I seedling emergence

Monocot (Single 

application)

TEP (21.82% a.i.) N/A EC25 = N/Ac

NOAEC = N/A

MRID 46264541

Acceptable

Dicot (Single 

application)

TEP (21.82% a.i.) Lettuce (Latuca sativa) EC25 = N/Ad

NOAEC = 0.225 lba.i./A

MRID 46264541

Acceptable

Plants - Tier I vegetative vigor

Monocot (Single 

application)

TEP (21.82% a.i.) N/A EC25 = N/Ac

NOAEC = N/A

MRID 46264540

Acceptable

Dicot (Single 

application)

TEP (21.82% a.i.) N/A EC25 = N/Ac

NOAEC = N/A

MRID 46264540

Acceptable

a

 There was an acute contact toxicity study with a slightly more sensitive LD50 for honey bees; however, it was not formally reviewed because it was not apart of 

the data package initially submitted to the US EPA.

b This study was not submitted as a part of the initial data package sent to the US EPA, but was submitted to the United Kingdom. Therefore, a formal review and 

classification of this study has not been performed by EFED scientists for this risk assessment. The results presented here are based on a preliminary review of the 

available data.

c There were no detrimental effects ≥25% for any test species and no species or endpoint exhibited a significant reduction from the controls.

d There were no detrimental effects ≥25% for any test species.

Table 2. Metaflumizone toxicity reference values (TRVs) (ppb) for aquatic organisms.

Exposure 

Scenario % a.i. Species Toxicity Reference Value

Reference

Freshwater Fish

Acute 

(96 hours)

TGAI 

(96.3%)

Rainbow Trout

Oncorhynchus mykiss

Observed effects assumed to occur at 1.79 ppba(The highest mortality was 40% 

in a single treatment level).

MRID 46264435

(Supplemental)

TEP 

(21.8%)

Rainbow Trout

Oncorhynchus mykiss

LC50 = 830 ppb nominal a.i.b MRID 46264537

(Supplemental)

Chronic TGAI Data Gap

Freshwater Invertebrates

Acute 

(48 hours)

TGAI 

(96.3%)

Water flea

Daphnia magna

Observed effects assumed to occur at 1.79 ppb a (The highest 

mortality/immobility of daphnids was 35% in a single treatment level. Effects 

assumed to have occurred at 1.79 ppb.)

MRID 46264505

(Supplemental)

TEP 

(21.8%)

Water flea

Daphnia magna

LC50 = 4784 ppb nominal a.i. b(All concentrations above 888ppb contained 

precipitate and were centrifuged.)

MRID 46264538

(Supplemental)
35

Table 2. Metaflumizone toxicity reference values (TRVs) (ppb) for aquatic organisms.

Exposure 

Scenario % a.i. Species Toxicity Reference Value

Reference

Chronic 

(21 days)

TGAI 

(96.3%)

Water flea

Daphnia magna

No endpoint could be calculated and exposure concentrations were unknown

(samples were not centrifuged prior to analysis). All nominal concentrations 

except the highest were below the level of solubility. Mortality occurred at the 

lowest concentration tested (measured: 0.0908 ppb) The highest 

mortality/immobility of daphnids was 13% in a single treatment level . No 

statistically significant difference in mortality or reproductive effects were seen.

MRID 46264507

(Supplemental)

Estuarine/Marine Fish

Acute

(96 hours)

TGAI 

(96.3%)

Sheepshead minnow

Cyprinodon 

variegatus

Observed effects assumed to occur at 1.79 ppb a(The highest mortality was 25% 

in a single treatment level.) 

MRID 46264521

(Supplemental)

Chronic

(41 days)

TGAI 

(96.3%)

Sheepshead minnow

Cyprinodon 

variegatus

No endpoint could be calculated and exposure concentrations were unknown 

(samples were not centrifuged prior to analysis). All nominal concentrations 

except the highest were below the level of solubility. No treatment-related effect 

on post-hatch survival was observed. Terminal length and blotted wet weights 

were unaffected.

MRID 46264502

(Supplemental)

Estuarine/Marine Invertebrates

Acute 

(96 hours)

TGAI 

(96.3%)

Eastern Oyster, 

Crassostrea virginica

Observed effects assumed to occur at 1.79 ppb a(No mortalities were observed 

during either definitive test. Shell growth was significantly reduced compared to 

the pooled control for each respective definitive test. Effects assumed to have 

occurred at 1.79 ppb.)

MRID 46264519

(Supplemental)

Chronic TGAI Data Gap

Freshwater Benthic Fish

Acute 

(96 hours)

TGAI 

(96.9%)

Common Carp

Cyprinus carpio

Observed effects assumed to occur at 1.79 ppb a(7% mortality in single 

treatment level.)

MRID 46264437

(Supplemental)

Chronic TGAI Data Gap

Freshwater Benthic Invertebrates

Acute

(10 days)

TGAI 

(96.9%)

Amphipod

Hyalella azteca

Sediment value: 

LC50 > 995000 μg a.i./kg sediment

Pore water value :

LC50 > 2740 μg a.i./L pore water

MRID 46264513

(Supplemental)

Chronic TGAI Data Gap

Estuarine/Marine Benthic Fish

Acute 

(96 hours)

TGAI 

(96.9%)

Channel Catfish

Ictalurus punctatus

Observed effects assumed to occur at 1.79 ppb a (Mortality was 3% in a single 

treatment level.) 

MRID 46264438

(Supplemental)

Chronic TGAI Data Gap

Estuarine/Marine Benthic Invertebrates

Acute 

(10 days)

TGAI 

(96.9%)

Amphipod

Leptocheirus 

plumulosus

Sediment value: 

LC50 > 935000 μg a.i./kg sediment

Pore water value:

LC50 > 1700 μg a.i./L pore water

MRID 46264512

(Supplemental)

Chronic TGAI Data Gap

Aquatic Plants
36

Table 2. Metaflumizone toxicity reference values (TRVs) (ppb) for aquatic organisms.

Exposure 

Scenario % a.i. Species Toxicity Reference Value

Reference

Algae Acute 

(120 hours)

TGAI 

(96.3%)

Pseudokirchneriella 

subcapitata

Observed effects assumed to occur at 1.79 ppb a(By 120 hours, the highest cell 

density percent inhibition was 15 %, the highest percent inhibition for biomass 

was 15%, and the highest percent inhibition for growth rate was 3%.)

MRID 46264511

(Supplemental)

TEP 

(21.8%)

Pseudokirchneriella 

subcapitata

Plant Biomass:

EC50/IC50 = 0.40 mg a.i./L

NOAEC = 0.0850 mg ai/L ai/L

MRID 46264539

(Supplemental)

Macrophytes

Acute 

(14 days)

TGAI 

(96.9%)

Duckweed

Lemna gibba

Observed effects assumed to occur at 1.79 ppb a(The highest frond number 

percent inhibition was 7%, the highest growth rate percent inhibition was 4%, the 

highest area under the growth curve percent inhibition was 7% , and the highest 

dry weight percent inhibition was 15%.)

MRID 46264515

(Supplemental)

a

The concentration bioavailable to the organisms is unknown because the test solution was not centrifuged prior to anaylsis. Due to this uncertainty, EFED 

assumed that any effects observed in the studies occurred at the limit of solubility (1.79 ppb).

b

These values were used for evaluation of risk via SPRAY DRIFT ONLY.
37

APPENDIX D. Estimating Ecological Surface Water Exposure EECs

Metaflumizone is a new insecticide and no surface water monitoring data is available. Estimated 

environmental concentrations (EECs) are based on simulated screening values using Tier II 

PRZM/EXAMS. The screening assessment for metaflumizone was completed using Tier II 

linked PRZM/EXAMS runs. Model runs were executed based on a broadcast application rate of 

0.00095 lb a.i/A (0.0011 kg a.i./ha) for selected crop and residential exposure scenarios. These 

exposure scenarios where chosen to bracket EECs modeled previously using a broader suite of 

scenarios but at a different application rate. A summary of input parameters used for the 

PRZM/EXAMS modeling is provided in Table D-1.

Table D-1 Summary of PRZM/EXAMS input parameters for modeling metaflumizone

Input Parameter Value Reference

Molecular Weight (gram mole -1) 506.4 Product chemistry submission

Vapor Pressure (torr) 9.30x10-11 MRID 462642-06 for parent; assumed same for M320 I 23

Aerobic Soil Metabolism Half-life 

(days) 134

The 90th percentile t1⁄2 from six values for parent (MRID 462644-

05/05/07)

Water column Half-life (days)

(Aerobic Aquatic Metabolism halflife) 284Aerobic soil t1⁄2x2: No acceptable aerobic aquatic metabolism study and 

No significant hydrolysis at pH 7 as per Guidance (US EPA, 2002)

Benthic sediment Half-life (days) 

(Anaerobic Aquatic Metabolism 

half-life) Stable Half-life for the total system >378 days (MRID 462644-22)

Application Rate (Kg a.i./ha) and

(Application Efficiency= 0.95) 0.0011

In this run we used the maximum yearly rate of 6 lbs of product*. 

Therefore, the rate for both mound and broadcast treatment will be the 

same. If we assume four applications/year, the maximum rate will be: 

four applications at a single rate of 0.00095 lb a.i/A (0.0011 kg/ha)**

Other Application Information

Applied at dates in April and May with 28-day application intervals. Assume 100% of 

the area is treated with 50% impervious and 50% pervious surfaces. Applied rate for 

impervious surfaces was 0.0001 lb a.i/A (assume 9%) ***

Depth of Incorporation (cm) 0 CAM=1 for bait application as broadcast or mound treatment

Spray Drift (fraction) 0% 

Bait no drift except for residential runs (see above, other application 

information)

Solubility (ppm) 0.00179 (MRID 462642-12)

Koc (L Kg-1) 30,753 Average for 7 soils (MRIDs 462644-11/12)

Hydrolysis Half-life @ pH 7 (days) Stable MRID 462644-19

Direct Aqueous Photolysis t1⁄2 

(days) 4.6 MRID 462644-20

* Based on RD communication the label will be changed so that the same maximum yearly limitation for mound treatment is 

the same as that for broadcast treatment. So, for mound treatments, the following will be added to the use rate column: 

"Not to exceed 6 lbs/acre total per year”

** Single application is calculated as follows: 6 lbs of product per acre per year/ 4 applications (assumed) = 1.5 lbs of 

product/single application per acre= 1.5 lbs product x 0.063% a.i = 0.00095 lb a.i/A= 0.00095 x 1.121= 0.0011 kg/ha

*** Was not able to reduce the drift below 9% because this is the lowest rate that can be entered into PE-5
38

Table D-2 summarizes scenarios selected to be used in PRZM/EXAMS modeling. Results from 

modeling these scenarios are summarized in Figures D-1 to D-4.

Table D-2 Metaflumizone proposed use patterns and representative scenarios

Residential Use Areas Scenarios

Other Use 

pattern Representative Scenarios

San Francisco, CA

The CA residential 

and the CA-impervious scenarios

with weather stations representing 

areas of the country that is listed 

in the previous column

Citrus 

Orchards

CA citrus (represent the lowest)

San Diego, CA S TX grapefruit (represent the highest)

Bakersfield, CA

Daytona Beach, FL Tree Nuts CA Almonds

Savannah, GA

Baton Rouge, LA Nurseries FL nurseries

Figure D-1 Estimated surface water EECs for non-residential use patterns.

0

0.005

0.01

0.015

0.02

Surface Water E

E

Cs (ppb)

STX grapefruits

FL nursery

CA almonds

CA citrus

Peak 21-day 60-day

Figure D-2. Estimated pore water EECs for non-residential use patterns 

0

0.002

0.004

0.006

0.008

0.01

0.012

P

ore Water E

E

Cs (ppb)

FL nursery

STX grapefruits

CA almonds

CA citrus

Peak 21 Day 60 Day
39

Figure D-3. Estimated surface water EECs for residential use patterns

0

0.005

0.01

0.015

0.02

0.025

Surface Water EECs (ppb)

LA- Baton Rouge

GA-Savanah

FL-Datona Beach

CA-San Diego

CA-Bakersfield

CA-San Francisco

Peak 21-day 60-day

Figure D-4. Estimated sediment EECs (μg/Kg) for representative use patterns

0

2

4

6

8

10

12

14

16

Sediment EECs (ug/Kg)

FL nursery

STX grapefruits

CA almonds

CA citrus

Peak 21 Day 60 Day
40

APPENDIX E. Summary of Persistent, Bioaccumulative, and Toxic 

Properties of Metaflumizone

Table E-1. Summary of Persistent, Bioaccumulative, and Toxic Properties of Metaflumizone

Property Metaflumizone Data National and International Criteria*

Persistence, water Hydrolysis = 416 days at pH 7 

Aqueous photolysis = 15 days

Aerobic aquatic metabolism= 16-45 days

Anaerobic aquatic <3 days in water column **

> 60 d to > 180 d

Persistence, soil Aerobic soil metabolism: Average = 187 days (8 soils); 

range= 73-408 days

Anaerobic soil metabolism: Average= 359 days; range= 

353-365 days

Field dissipation (bareground plots): Average = 51 days; 

range= 6-116 days

Field dissipation (cropped plots): Average = 196 days; 

range= 151-240 days

> 60 d to > 365 d

Persistence, sediment Aerobic aquatic >100 days

Anaerobic aquatic >378 days 

(In sediment and whole system)

> 60 d to > 365 d

Bioaccumulation 3,500 in edible tissues, 12,000 in nonedible tissues, and 

7,325 in whole fish tissues

log Kow = 5.1

>1000 to >5000

Log Kow > 5

Toxicity Terrestrial toxicity profile demonstrates that 

metaflumizone is moderately to highly toxic to birds on 

an acute dietary basis, and has a strong potential for 

chronic reproductive effects in both mammalian and avian 

species.

Best professional judgment

** Although the anaerobic aquatic half-life is <3 days in the water column, this is not due to degradation of the chemical. Rather, 

metaflumizone’s high koc indicates that it will quickly and readily partition to the sediment compartment where it will persist.

* Ranges of numeric criteria reflect different institutional policies, regulations, and treaties regarding PBT classification (Sources include:

- USEPA Office of Environmental Information. Federal Register: October 29, 1999 (Volume 64, Number 209). Rules and Regulations. Page 

58665-58753. On-line at http://www.epa.gov/fedrgstr/EPA-WASTE/1999/October/Day-29/f28169.htm 

- United Nations Economic Commission for Europe (UNECE) Convention on Long-Range Transboundary Air Pollution (LRTAP) (Ref. 54); 

PTBs (February 1996)) http://www.unece.org/env/lrtap/

- United Nations Environmental Programme http://www.chem.unep.ch/pops/default.html

- Environment Canada Toxic Substances Management Policy (June 1995)

- International Council of Chemical Associations http://www.icca-chem.org/
41

APPENDIX F. Calculations for Determining Risk to Birds and Mammals 

Resulting from Consumption of Aquatic Organisms that have 

Bioaccumulated Metaflumizone 

I. GENERAL MODEL DESCRIPTION

For estimating risks to fish-eating birds and mammals resulting from consumption of aquatic prey that 

have bioaccumulated metaflumizone, the KABAM model version 1.0 (KOW (based) Aquatic 

BioAccumulation Model) was used (USEPA 2009). Specifically, 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. The 

bioaccumulation portion of KABAM is based upon Arnot and Gobas (2004) who parameterized a 

bioaccumulation model based on PCBs and some pesticides (e.g., lindane, DDT) in freshwater aquatic 

ecosystems. KABAM relies on a chemical's octanol-water partition coefficient (KOW) to estimate uptake 

and elimination constants through respiration and diet of organisms in different trophic levels. Pesticide 

tissue residues are calculated for different levels of an aquatic food web. The model then uses pesticide 

tissue concentrations in aquatic animals to estimate dose- and dietary-based exposures and associated 

risks to mammals and birds consuming aquatic organisms, using an approach that is similar to the T-REX 

model (USEPA 2008). 

KABAM (v. 1.0) incorporates 7 trophic levels to describe bioaccumulation of a pesticide in a model 

aquatic food web: 

1) phytoplankton

2) zooplankton (e.g., Daphnia sp.)

3) benthic invertebrates (e.g., Chironomus sp., crayfish)

4) filter feeders (e.g., mussels, clams)

5) small fish (e.g., young of the year)

6) medium sized fish (e.g., adult bluegill)

7) larger upper-trophic level fish (e.g., largemouth bass)

Pesticide concentrations in organisms of the aquatic trophic levels listed above are used to estimate acute 

and chronic exposures of mammals and birds consuming aquatic organisms. The model user can define 

the mammals and birds of concern, by defining the body weight and diet of each bird and mammal. 

Default values are available for several mammals and birds of concern. Available pesticide-specific acute 
42

and chronic toxicity data for mammals and birds are used to calculate risk quotients for estimated 

exposures due to bioaccumulation of a pesticide in an aquatic ecosystem. 

Model inputs are included in the 2 "Inputs" worksheets. The only required inputs to the KABAM tool are: 

1) Log KOW value of the pesticide

2) KOC value of the pesticide

3) predicted pesticide concentration in sediment pore water (PRZM/EXAMS)

4) predicted pesticide concentration in water (PRZM/EXAMS)

5) available acute and chronic toxicity data for pesticide specific exposures to birds and mammals. 

All other inputs in the "chemical specific inputs" and "ecosystem inputs" worksheets have default values. 

No input is necessary from the model user, but these parameter values can be altered according to the 

preferences of the user. The model user should consult the User's guide for KABAM before altering 

default values in the KABAM tool. If default parameter values are altered by the model user, their cells 

will be highlighted yellow.

The "Parameters & Calculations" worksheet allows the model user to see which parameters were 

incorporated into the calculation of the tissue concentrations of the pesticide of interest. This worksheet is 

read only.

The "Results" page includes pesticide tissue concentrations per trophic level, separate contributions of 

dietary and respiratory intakes to overall pesticide body concentration of aquatic organisms. It also 

includes bioconcentration, bioaccumulation, biomagnification and biota-sediment accumulation factors 

(BCF, BAF, BMF and BSAF, respectively) for aquatic organisms. In addition, this page also incorporates 

potential dietary and dose exposures of the pesticide of concern to mammals and birds consuming aquatic 

organisms. This worksheet is read only.

For a thorough description of KABAM, its assumptions, calculations, uncertainties and additional 

guidance, see the user's guide and technical documentation (USEPA 2009).

II. MODEL INPUT PARAMETERS

Chemical-specific parameters used for modeling metaflumizone are provided in Tables F-1 to F-3 below. 

Table F-1. Chemical characteristics of Metaflumizone.

Characteristic Value Comments/Guidance

Pesticide Name Metaflumizone

Log KOW 5.1 Kow for E-isomer (MRID 462642-13)

KOW 125893 Calculated value
43

Table F-1. Chemical characteristics of Metaflumizone.

Characteristic Value Comments/Guidance

KOC (L/kg OC) 30753

Mean Koc from representative registrant-submitted studies 

(MRID 462644-11, 462644-12)

Time to steady 

state (TS; days) 37 Calculated value

Pore water EEC 

(μg/L)

0.0072

60-d average 1 in 10 year pore water EEC for the S. TX 

Grapefruit scenario. 60-d average chosen to approximate the 

time to reach steady state.

Water Column 

EEC (μg/L)

0.0092

60-d average 1 in 10 year surface water EEC for the S. TX 

Grapefruit scenario. 60-d average chosen to approximate the 

time to reach steady state. 

Table F-2. Input parameters for rate constants. "calculated" indicates that model will calculate 

rate constant. 

Trophic level

k1 

(L/kg*d)

k2 

(d-1)

kD 

(kg-food/kgorg/d)kE 

(d-1)

kM* 

(d-1)

phytoplankton calculated calculated 0* 0* 0

zooplankton calculated calculated calculated calculated 0

benthic 

invertebrates calculated calculated calculated calculated 0

filter feeders calculated calculated calculated calculated 0

small fish calculated calculated calculated calculated 0

medium fish calculated calculated calculated calculated 0

large fish calculated calculated calculated calculated 0

* Default value is 

0. 

k1 and k2 represent the uptake and elimination constants respectively, through respiration.
44

kD and kE represent the uptake and elimination constants, respectively, through diet.

kM represents the metabolism rate constant. 

Table F-3. Mammalian and avian toxicity data for Metaflumizone. These are required inputs.

Animal

Measure of 

effect (units) Value Species

If selected 

species is 

"other," 

enter body 

weight (in 

kg) here.

Avian

LD50 (mg/kgbw) > 73.8Mallard (calculated from 

mallard LC50 study) 0.203

LC50 (mg/kgdiet) > 156Mallard (indefinite (“>” )LC50 

value from MRID 46264428) 0.203

NOAEC 

(mg/kg-diet) 7.6

Northern bobwhite quail 

(MRID 46264430)

Mineau Scaling

Factor 1.15

Default value for all species 

is 1.15 (for chemical specific 

values, see Mineau et al. 

1996).

Mammalian

LD50 (mg/kgbw)LD50 value not available (no 

effects at highest conc.)

LC50 (mg/kgdiet) N/A

Chronic 

Endpoint 20 laboratory rat (MRID 

46264315) units of chronic 

endpoint*

mg/kg-bw

III. ECOSYSTEM INPUTS

Input parameters for the model aquatic ecosystem are provided in Tables F-4 to F-9 below.

Table F-4. Abiotic characteristics of the model aquatic ecosystem.

Characteristic Value Guidance*

Concentration of 

Particulate Organic 

Carbon 

(XPOC; kg OC/ L)

0.00E+00

When using EECs generated by PRZM/EXAMS, use a value of “0” 

for both POC and DOC. Concentration of 

Dissolved Organic 

Carbon 

(XDOC; kg OC/L)

0.00E+00
45

Table F-4. Abiotic characteristics of the model aquatic ecosystem.

Characteristic Value Guidance*

Concentration of 

Dissolved Oxygen 

(COX; mg O2/L)

5.0 Default value is 5.0 mg O2/L when using EECs generated by 

PRZM/EXAMS.

Water Temperature 

(T; oC) 15

Value is defined by the average water temperature of the EXAMS 

pond when using EECs generated by PRZM/EXAMS. Model user 

should consult output file of EXAMS to define this value.

Concentration of 

Suspended Solids 

(CSS; kg/L)

3.00E-05 Default value is 3.00x10-5

kg/L when using EECs generated by 

PRZM/EXAMS.

Sediment Organic 

Carbon 

(OC; %)

4.0% Default value is 4.0% when using EECs generated by 

PRZM/EXAMS.

*When using pesticide concentrations from monitoring data or mesocosm studies, consult Appendix B 

of the User’s Guide for specific guidance on selecting values for these parameters.

Table F-5. Characteristics of aquatic biota of the model ecosystem.

Trophic Level

Wet Weight 

(kg) % lipids % NLOM % Water

Do 

organisms 

in trophic 

level 

respire 

some pore 

water?

sediment* N/A 0.0% 4.0% 96.0% N/A

phytoplankton N/A 2.0% 8.0% 90.0% no

zooplankton 1.0E-07 3.0% 12.0% 85.0% no

benthic 

invertebrates 1.0E-04 3.0% 21.0% 76.0% yes

filter feeders 1.0E-03 2.0% 13.0% 85.0% yes

small fish 1.0E-02 4.0% 23.0% 73.0% yes

medium fish 1.0E-01 4.0% 23.0% 73.0% yes

large fish 1.0E+00 4.0% 23.0% 73.0% no

*Note that sediment is not a trophic level. It is included in this table because it is consumed by

aquatic organisms of the KABAM foodweb.

N/A = not applicable

Table F-6. Diets of aquatic biota of the model ecosystem.

Diet for: 

Trophic level in diet Zooplankton

Benthic 

Invertebrates

Filter 

Feeder Small Fish

Medium 

Fish Large Fish

sediment* 0.0% 34.0% 34.0% 0.0% 0.0% 0.0%
46

phytoplankton 100.0% 33.0% 33.0% 0.0% 0.0% 0.0%

zooplankton 33.0% 33.0% 50.0% 0.0% 0.0%

benthic invertebrates 0.0% 50.0% 50.0% 0.0%

filter feeders 0.0% 0.0% 0.0%

small fish 50.0% 0.0%

medium fish 100.0%

Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

*Note that sediment is not a trophic level. It is included in this table because it is consumed by aquatic organisms of the 

KABAM foodweb.

Table F-7. Identification of mammals and birds feeding on aquatic biota of 

the model ecosystem.

Mammal/Bird # Name Body weight (kg)

Mammal 1 fog/water shrew 0.018

Mammal 2 rice rat/star-nosed mole 0.085

Mammal 3 small mink 0.45

Mammal 4 large mink 1.8

Mammal 5 small river otter 5

Mammal 6 large river otter 15

Bird 1 sandpipers 0.02

Bird 2 cranes 6.7

Bird 3 rails 0.07

Bird 4 herons 2.9

Bird 5 small osprey 1.25

Bird 6 white pelican 7.5

Table F-8. Diets of mammals feeding on aquatic biota of the model ecosystem.

Trophic level in 

diet

Diet for: 

fog/water 

shrew

rice 

rat/starnosed 

mole

small 

mink

large 

mink

small 

river otter

large river 

otter

phytoplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

zooplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

benthic 

invertebrates 100.0% 34.0% 0.0% 0.0% 0.0% 0.0%

filter feeders 0.0% 33.0% 0.0% 0.0% 0.0% 0.0%

small fish 0.0% 33.0% 0.0% 0.0% 0.0% 0.0%

medium fish 0.0% 0.0% 100.0% 100.0% 100.0% 0.0%

large fish 0.0% 0.0% 0.0% 0.0% 0.0% 100.0%

Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

Table F-9. Diets of birds feeding on aquatic biota of the model ecosystem.

Diet for: 

Trophic level in 

diet sandpipers cranes rails herons

small 

osprey

white 

pelican
47

Table F-9. Diets of birds feeding on aquatic biota of the model ecosystem.

Diet for: 

Trophic level in 

diet sandpipers cranes rails herons

small 

osprey

white 

pelican

phytoplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

zooplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

benthic 

invertebrates 33.0% 33.0% 50.0% 50.0% 0.0% 0.0%

filter feeders 33.0% 33.0% 0.0% 0.0% 0.0% 0.0%

small fish 34.0% 0.0% 50.0% 0.0% 0.0% 0.0%

medium fish 0.0% 34.0% 0.0% 50.0% 100.0% 0.0%

large fish 0.0% 0.0% 0.0% 0.0% 0.0% 100.0%

Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

IV. INTERMEDIATE PARAMETERS AND CALCULATIONS

Table F-10. Input parameters and calculations relevant to derivation of CB.

Parameter

Phyto 

plankton

Zoo 

plankton

Benthic 

Invertebrates

Filter 

Feeders Small Fish

Medium 

Fish Large Fish

Equation A1

CB 0.000052 0.00004085 0.000046 0.000030 0.000070 0.000086 0.00013

CBD 0.000000 0.00000156 0.000004 0.000003 0.000017 0.000035 0.000078

CBR 0.00005225 0.00003929 0.00004186 0.00002753 0.00005228 0.00005015 0.00004783

CS 0.000009

CWDP 0.00000001

CWTO 0.00000001

k1 9644.313 42628.237 3799.246 1697.061 758.049 338.608 151.251

k2 1.595752 9.898868 0.807861 0.548942 0.125300 0.055970 0.025001

kD 0.000000 0.297943 0.105714 0.046251 0.052983 0.037509 0.026554

kE 0.000000 0.055652 0.013660 0.009091 0.005198 0.004593 0.003550

kG 0.100000 0.012559 0.003155 0.001991 0.001256 0.000792 0.000500

kM 0 0 0 0 0 0 0

mo 1 1 0.95 0.95 0.95 0.95 1

mp 0 0 0.05 0.05 0.05 0.05 0

Σ (Pi * CDi) 0 5.22456E-05 3.37275E-05 3.3728E-05 4.3517E-05 5.7981E-05 8.5592E-05

Ф 1.00000000

Equation A2

XPOC 0.0000000

XDOC 0.0000000

KOW 125893

Ф 1.00000000

Equation A4

CS 0.0000

CSOC 0.0002

CWDP 0.00000
48

Table F-10. Input parameters and calculations relevant to derivation of CB.

Parameter

Phyto 

plankton

Zoo 

plankton

Benthic 

Invertebrates

Filter 

Feeders Small Fish

Medium 

Fish Large Fish

KOC 30753

OC 4%

Equation A5

Cox N/A 5

EW N/A 0.54018104

GV N/A 0.007891472 0.703328201 3.14165167 14.0332425 62.6841919 280

k1 9644.312647 42628.23666 3799.245591 1697.06067 758.049155 338.60812 151.250691

KOW 125893

WB N/A 0.0000001 0.0001 0.001 0.01 0.1 1

Equation A6

k1 9644.312647 42628.23666 3799.245591 1697.06067 758.049155 338.60812 151.250691

k2 1.595751884 9.898867973 0.807860869 0.54894198 0.12530014 0.05596952 0.02500067

KBW 6043.741977 4306.374908 4702.846413 3091.51189 6049.8666 6049.8666 6049.8666

KOW 125893

VLB 0.02 0.03 0.03 0.02 0.04 0.04 0.04

VNB 0.08 0.12 0.21 0.13 0.23 0.23 0.23

VWB 0.9 0.85 0.76 0.85 0.73 0.73 0.73

β 0.35 0.035

Equation A7

kG 0.1 0.012559432 0.003154787 0.00199054 0.00125594 0.00079245 0.0005

T 15

WB N/A 0.0000001 0.0001 0.001 0.01 0.1 1

Equation A8

Cox N/A N/A N/A 5 N/A N/A N/A

CSS N/A N/A N/A 3.00E-05 N/A N/A N/A

ED N/A 0.490733055

GD N/A 6.07E-08 2.15E-05 9.42E-05 1.08E-03 7.64E-03 5.41E-02

GV N/A N/A N/A 3.14 N/A N/A N/A

kD 0 2.98E-01 1.06E-01 4.63E-02 5.30E-02 3.75E-02 2.66E-02

KOW 125893

T N/A 15

WB N/A 0.0000001 0.0001 0.001 0.01 0.1 1

Equation A9

Cox N/A N/A N/A 5 N/A N/A N/A

CSS N/A N/A N/A 3.00E-05 N/A N/A N/A

ED N/A 0.4907

GD N/A 0.0000 0.0000 0.0000942 0.0011 0.0076 0.0541

GF N/A 0.000000 0.000015 0.000066 0.000726 0.004965 0.034777

GV N/A N/A N/A 3.1417 N/A N/A N/A

kE 0 0.0557 0.0137 0.0091 0.0052 0.0046 0.0035

KGB N/A 0.2657 0.1841 0.2800 0.1460 0.1885 0.2080

KOW N/A 125893

T N/A 15

VLB N/A 0.03 0.03 0.02 0.04 0.04 0.04
49

Table F-10. Input parameters and calculations relevant to derivation of CB.

Parameter

Phyto 

plankton

Zoo 

plankton

Benthic 

Invertebrates

Filter 

Feeders Small Fish

Medium 

Fish Large Fish

VLD N/A 0.02 0.01650 0.0165 0.03 0.035 0.04

VLG N/A 0.007966 0.005876 0.005876 0.003571 0.004311 0.004979

VNB N/A 0.12 0.21 0.13 0.23 0.23 0.23

VND N/A 0.08 0.0796 0.0796 0.165 0.22 0.23

VNG N/A 0.03186 0.02835 0.02835 0.09819 0.13548 0.14315

VWB N/A 0.85 0.76 0.85 0.73 0.73 0.73

VWD N/A 0.9 0.9039 0.9039 0.805 0.745 0.73

VWG N/A 0.9602 0.9658 0.9658 0.8982 0.8602 0.8519

WB N/A 0.0000001 0.0001 0.001 0.01 0.1 1

β N/A 0.035 0.035 0.035 0.035 0.035 0.035

εL N/A 0.72 0.75 0.75 0.92 0.92 0.92

εN N/A 0.72 0.75 0.75 0.6 0.6 0.6

εW N/A 0.25 0.25 0.25 0.25 0.25 0.25

Calculation of BCF values

CBCF 5.55196E-05 3.95597E-05 4.27316E-05 2.809E-05 5.4971E-05 5.4971E-05 5.5576E-05

See Appendix A of KABAM user's guide (USEPA 2009) and technical documentation for equation 

details.

V. MODEL RESULTS

The results from the bioaccumulation modeling with metaflumizone are shown in Tables F-11 to F-16

and Figure F-1 below. Total BCFs predicted for fish are approximately 6,000 L/kg w.w. (Table F-12). 

These values are in the same range as those measured BCF in bluegill sunfish of 3,500 (edible tissue) and 

12,000 (non-edible tissue; MRID 462645-04). This similarity among predicted and measured BCF values 

suggests that key bioaccumulation model assumptions (e.g., no chemical metabolism) are appropriate for 

metaflumizone. Furthermore, the biomagnification of metaflumizone (i.e., increasing concentration with 

increasing trophic level) appears to be relatively modest (BMF for large fish of 1.5; Table F-13) but 

nonetheless indicates that diet is still a significant contribution to aquatic organism exposure (Figure F1). 

In terms of risks to piscivorous birds and mammals, no acute or chronic risks are seen based on predicted 

concentrations in aquatic food web (Table F-16). For example, the maximum concentration predicted is 

seen for large fish (0.12 ppm) which is about 1/50th the avian dietary NOAEC of 7.6 ppm. All other RQ 

values are two or more orders of magnitude below the Agency’s levels of concern (e.g., 0.5 for acute risk 

to non-listed species; 0.1 for acute risk to listed species and 1.0 for chronic risk to listed and non-listed 

species). 

Table F-11. Estimated concentrations of Metaflumizone in ecosystem components.

Ecosystem Component

Total 

concentration 

(μg/kg-ww)

Lipid 

normalized 

concentration 

(μg/kg-lipid)

Contribution 

due to diet 

(μg/kg-ww)

Contribution 

due to 

respiration 

(μg/kg-ww)

Water (total)* 0 N/A N/A N/A

Water (freely dissolved)* 0 N/A N/A N/A
50

Table F-11. Estimated concentrations of Metaflumizone in ecosystem components.

Ecosystem Component

Total 

concentration 

(μg/kg-ww)

Lipid 

normalized 

concentration 

(μg/kg-lipid)

Contribution 

due to diet 

(μg/kg-ww)

Contribution 

due to 

respiration 

(μg/kg-ww)

Sediment (pore water)* 0 N/A N/A N/A

Sediment (in solid)** 9 N/A N/A N/A

Phytoplankton 52 2612 N/A 52.25

Zooplankton 41 1362 1.56 39.29

Benthic Invertebrates 46 1539 4.32 41.86

Filter Feeders 30 1516 2.79 27.53

Small Fish 70 1744 17.50 52.28

Medium Fish 86 2140 35.45 50.15

Large Fish 126 3152 78.24 47.83

* Units: μg/L; **Units: μg/kg-dw

Figure F-1. Total pesticide concentration 

per trophic level

0

20

40

60

80

100

120

140

Zooplankton Benthic

Invertebrates

Filter Feeders Small Fish Medium Fish Large Fish

Trophic Level

Concentration (μg/kg)

Contribution due to respiration (μg/kg-ww)

Contribution due to diet (μg/kg-ww)

Table F-12. Total BCFand BAF values of Metaflumizone in 

aquatic trophic levels.

Trophic Level

Total BCF 

(μg/kgww)/(μg/L)

Total BAF 

(μg/kgww)/(μg/L)

Phytoplankton 6044 5687

Zooplankton 4306 4447

Benthic Invertebrates 4652 5027
51

Filter Feeders 3058 3301

Small Fish 5984 7596

Medium Fish 5984 9317

Large Fish 6050 13723

Table F-13. Lipid-normalized BCF, BAF, BMF and BSAF values of Metaflumizone in 

aquatic trophic levels.

Trophic Level

BCF 

(μg/kglipid)/(μg/L)

BAF 

(μg/kglipid)/(μg/L)

BMF 

(μg/kglipid)/(μg/kglipid)

BSAF 

(μg/kglipid)/(μg/kgOC)

Phytoplankton 302187 284367 N/A 12

Zooplankton 143546 148230 0.52 6

Benthic Invertebrates 155055 167582 1.17 7

Filter Feeders 152893 165029 1.16 7

Small Fish 149601 189897 1.20 8

Medium Fish 149601 232934 1.30 10

Large Fish 151247 343079 1.47 14

Table F-14. Calculation of EECs for mammals and birds consuming fish contaminated by 

Metaflumizone.

Wildlife Species

Biological Parameters

EECs (pesticide 

intake)

Body

Weight

(kg)

Dry Food 

Ingestion 

Rate (kg-dry

food/kgbw/day)

Wet Food 

Ingestion 

Rate (kg-wet 

food/kgbw/day)

Drinking 

Water

Intake

(L/d)

Dose Based 

(mg/kgbw/d)

Dietary

Based 

(ppm)

Mammalian

fog/water shrew 0.02 0.140 0.585 0.003 0.027 0.05

rice rat/starnosed mole 0.1 0.107 0.484 0.011 0.024 0.05

small mink 0.5 0.079 0.293 0.048 0.025 0.09

large mink 1.8 0.062 0.229 0.168 0.020 0.09

small river otter 5.0 0.052 0.191 0.421 0.016 0.09

large river otter 15.0 0.042 0.157 1.133 0.020 0.13

Avian

sandpipers 0.0 0.228 1.034 0.004 0.0506 0.05

cranes 6.7 0.030 0.136 0.211 0.0074 0.05

rails 0.1 0.147 0.577 0.010 0.0335 0.06

herons 2.9 0.040 0.157 0.120 0.0104 0.07

small osprey 1.3 0.054 0.199 0.069 0.0171 0.09

white pelican 7.5 0.029 0.107 0.228 0.0135 0.13
52

Table F-15. Calculation of toxicity values for mammals and birds 

consuming fish contaminated by Metaflumizone.

Wildlife Species

Toxicity Values

Acute Chronic

Dose 

Based 

(mg/kgbw)

Dietary

Based 

(mg/kg-diet)

Dose Based 

(mg/kg-bw)

Dietary

Based 

(mg/kg-diet)

Mammalian

fog/water shrew 0.00 N/A 42.00 400

rice rat/starnosed mole 0.00 N/A 28.49 400

small mink 0.00 N/A 18.78 400

large mink 0.00 N/A 13.28 400

small river otter 0.00 N/A 10.29 400

large river otter 0.00 N/A 7.82 400

Avian

sandpipers 52.13 156.00 N/A 7.6

cranes 124.69 156.00 N/A 7.6

rails 62.91 156.00 N/A 7.6

herons 109.97 156.00 N/A 7.6

small osprey 96.93 156.00 N/A 7.6

white pelican 126.82 156.00 N/A 7.6

Table F-16. Calculation of RQ values for mammals and birds 

consuming fish contaminated by Metaflumizone.

Wildlife Species

Acute Chronic

Dose 

Based

Dietary 

Based

Dose Based Dietary 

Based

Mammalian

fog/water shrew #DIV/0! N/A 0.001 0.000

rice rat/starnosed mole #DIV/0! N/A 0.001 0.000

small mink #DIV/0! N/A 0.001 0.000

large mink #DIV/0! N/A 0.001 0.000

small river otter #DIV/0! N/A 0.002 0.000

large river otter #DIV/0! N/A 0.003 0.000

Avian

sandpipers 0.001 0.000 N/A 0.006

cranes 0.000 0.000 N/A 0.007

rails 0.001 0.000 N/A 0.008

herons 0.000 0.000 N/A 0.009

small osprey 0.000 0.001 N/A 0.011

white pelican 0.000 0.001 N/A 0.017
53

VI. REFERENCES

Arnot, J.A. and F.A.P.C. Gobas. 2004. A food web bioaccumulation model for organic chemicals in 

aquatic ecosystems. Environmental Toxicology and Chemistry, v23 (10), 2343-2355.

Mineau, P., Collins, B.T. and A. Baril. 1996. On the use of scaling factors to improve interspecies 

extrapolation of acute toxicity in birds. Regulatory Toxicology and Pharmacology, 24: 24-29.

USEPA. 2002. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and 

Transport of Pesticides, Version II. US Environmental Protection Agency, Washington DC. Online at: 

http://www.epa.gov/oppefed1/models water/input_guidance2_28_02.htm.

USEPA. 2008. User’s Guide: T-REX Version 1.4.1 (Terrestrial Residue Exposure model). United States 

Environmental Protection Agency. Environmental Fate and Effects Division.

USEPA. 2009. User’s Guide and Technical Documentation: KABAM version 1.0 (KOW (based) Aquatic 

BioAccumulation Model). United States Environmental Protection Agency. Office of Pesticide 

Programs, Environmental Fate and Effects Division. (available at: 

http://www.epa.gov/oppefed1/models/water/kabam/kabam_user_guide.html)