OFFICE OF

CHEMICAL SAFETY AND

POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

Chemical: Fosamine Ammonium 

 PC Code: 106701 

DP Barcode: 415252 

Date: September 3, 2015 

MEMORANDUM 

SUBJECT: Registration Review Ecological Risk Assessment for Fosamine Ammonium 

(PC Code 106701; DP Barcode 415252) 

TO: James Parker, Chemical Review Manager 

 Neil Anderson, Chief 

 Risk Management and Implementation Branch 6 

 Pesticide Reevaluation Division (7508P) 

THROUGH: Dana Spatz, Chief 

 Environmental Risk Branch 3 

Environmental Fate and Effects Division (7507P) 

FROM: Frank T. Farruggia, Ph.D., Biologist 

 Rosanna Louie-Juzwiak, RAPL 

 Environmental Risk Branch 3 

 Environmental Fate and Effects Division (7507P) 

EXECUTIVE SUMMARY 

The Environmental Fate and Effects Division (EFED) has completed the ecological risk assessment as part 

of the Registration Review of the herbicide fosamine ammonium (PC Code 106701). Fosamine 

ammonium is a non-selective herbicide used to control undesirable brush/herbaceous plant species 

used for brush control of nonagricultural rights-of-way (e.g., highways, railroads, and utilities), industrial 

sites, and fencerows. In 1995 the Agency conducted a risk assessment on the potential exposure and risk 

to the environment from registered uses of fosamine ammonium as part of the Reregistration Eligibility 

Decision (USEPA 1994). This assessment relies upon earlier assessments that found fosamine 

ammonium does not result in risk concerns to birds, mammals, invertebrates, fish, aquatic invertebrates 

or aquatic plant species as risk quotients (RQs) did not exceed the Agency's levels of concern (LOCs). 

The following assessment focuses on the potential risks to terrestrial and semi-aquatic plants from 

current fosamine ammonium uses. The registrant has submitted plant toxicity data on the technical 

grade fosamine ammonium (MRID 42647601). Toxicity data on fosamine ammonium end-use product 

formulations are not available, and thus it is uncertain whether or not the formulations are more or less 

toxic than technical grade active ingredient. Several plant toxicity studies available in the open literature 
2

evaluated the efficacy of products containing fosamine ammonium on target plants and trees at 

registered application rates. These studies do not readily allow for estimating a corresponding NOEL or 

LOEL from these studies to compare against available registrant-submitted plant toxicity studies; 

however, there were no tested species that reported effects (e.g., reduction in height or growth) at an 

exposure rate lower than what is captured in the submitted plant studies. In addition, fosamine 

ammonium products are intended to control unwanted brush; although no toxicity data using woody 

species of plants have been submitted, some woody species are expected to be affected. 

 

Based on the available toxicity data, risks to terrestrial plants are expected. These risks include potential 

risk to agricultural crops such as corn and soybeans, and to native non-target vegetation. Based on 

exposures and distance from the edge of the field, the estimated risks extend to 290 ft and beyond 1000 

feet for sensitive monocot and dicot species respectively via spray drift, when applied by air. Coarser 

droplet spectra reduce the distances. For monocots such as corn, the most sensitive monocot tested, 

there are LOC exceedances out to 115 feet, and for dicots such as soybean, risk extends to 318 feet. 

Ground spray with coarser droplet sizes reduces the predicted drift distance greatly for monocots (from 

154 to 36 ft) but the LOC continues to be exceeded for dicots to greater than 1000 feet for the most 

sensitive tested species, and at least 194 feet for the least sensitive dicot. 

Summary of Prior Risk Conclusions

For birds, small mammals, terrestrial invertebrates, aquatic plants, and aquatic animals, the estimated 

acute risk quotients (RQs) did not exceed the Agency's levels of concern (LOCs). Acute risk to terrestrial 

plants could not be assessed at the time because data were still outstanding for corn, sugarbeet, pea, 

and cucumber. Available fate and toxicity data are summarized in Appendix B. 

In the risk assessment conducted in support of the reregistration evaluation, the estimated 

environmental concentrations estimated for aquatic exposure were modeled using GENEEC, predicting a 

maximum concentration of 8.8 ppm resulting from runoff, based on the 24 lb a.i./A application rate. All 

acute RQs were below the LOC (i.e., <0.05). Chronic data for aquatic animals were unavailable; however, 

based on the short half-life of fosamine ammonium in the aerobic soil metabolism study (i.e., <4 days), 

the fish early life stage and aquatic invertebrate life cycle studies were not required. Given the limited 

(i.e., single application) frequency of exposure and the observed low acute toxicity to aquatic organisms, 

chronic risks to aquatic organisms were expected to be low. 

Chronic exposure RQs for small mammals did not exceed Agency LOCs. Chronic data were unavailable 

for fish and aquatic invertebrates. The only level of concern exceeded (RQ = 23) was from a mallard 

reproduction study; however, there is some uncertainly associated with the experimental results 

(D214645). EPA suggested modifying the label to account for the potential adverse effects on avian 

reproduction including threatened and endangered species exposed to fosamine ammonium. This 

change is no longer an issue since EPA later (1997; per memo D231023) accepted a mallard 

reproduction study (MRID 44143501) showing the registered uses of fosamine ammonium do not result 

in RQs that exceed the Agency's LOCs. 

Use of fosamine ammonium may, however, directly impact terrestrial and semi-aquatic plants, and, 

through loss of food source, indirectly impact animals depending on terrestrial plants for food or 

habitat. 
3

Chemical Properties and Fate Overview: 

Although fosamine ammonium is highly soluble in water and mobile in various soils, fosamine 

ammonium degrades rapidly in the environment via microbial-mediated degradation in soil, which are 

supported by available terrestrial field data. Based on its physical and chemical properties alone, 

fosamine ammonium has low potential to volatilize from soils (vapor pressure) or from water (Henry’s 

Law Constant). It is also unlikely to bioaccumulate in fish given the low value of the Log n-octanol/water 

partition coefficient. Fosamine ammonium is stable to hydrolysis and photolysis (MRIDs 40133701, 

40133702, and 40133703), and no degradation was observed under anaerobic conditions (MRIDs 

42060602 and 42680701). No aerobic aquatic metabolism data have been submitted to the EPA. Major 

degradates (>10% of the applied) of fosamine ammonium are carbamolyphosphonic acid (CPA) and 

carboxylphosphonic acid (ING-3003), and carbon dioxide (MRIDs 42020206 and 42724301). There are 

limited environmental fate data available for CPA and ING-3003; however, based on the ecological data, 

these compounds are of low toxicological concern. 

Exposure Estimation 

Current fosamine ammonium product labels (Table 1) were used to derive EECs relevant to terrestrial 

and wetland plants using the TerrPlant and AgDrift models. Detailed information about the TerrPlant 

model can be found at http://www.epa.gov/oppefed1/models/terrestrial/ and at 

http://www.epa.gov/oppefed1/models/water/index.htm#agdrift. The AgDRIFT spray drift model (v2.01; 

May 2001;) was used to assess exposures of organisms to fosamine ammonium deposited on terrestrial 

or aquatic habitats by spray drift alone.

Table 1. Maximum Fosamine Ammonium Use Rate 

Group name Uses represented

Max. Rate per 

App. (lb 

a.i./A) 

Maximum 

Annual Rate (lb 

a.i./A) 1 

Application 

Method 2

Terrestrial 

Non-Food Crop 

Agricultural and 

nonagricultural right-ofway/fencerows/ hedgerows 

Agricultural uncultivated 

areas 

Airports/landing fields 

Industrial areas (outdoor) 

Nonagricultural uncultivated 

areas/soils 

Sewage disposal areas 

24 12 (aerial) 

24 (ground) 

Aerial and 

ground 

Forestry Pine (forest/shelterbelt) 6 12 Aerial and 

ground 1

 Application methods reported for any labeled application rates (maximum rate per application and/or seasonal 

maximum dose/year) for that crop/use. The term ground includes any of the ground methods previously defined 
4

as ground. In some cases when both aerial and ground application methods are reported for a crop/use, both 

methods may not be used at the maximum reported application rates (single application and/or seasonal 

application). 

2

 Aerial refers to helicopter application only. 

Terrestrial Plant Toxicity Data and Related Uncertainty in the Assessment of Risk to Terrestrial Plants 

Terrestrial Plant Toxicity Exposure and Risk Assessment 

For this risk assessment, terrestrial plant toxicity data for seedling emergence (850.4100) and vegetative 

vigor (850.4150) stages of plant development were re-evaluated (MRID 42647601). In the original 

Agency review, the results for corn, sugarbeet, pea and cucumber were considered invalid for use due to 

the study authors’ use of chemicals for sterilization of the soils. Two of the chemicals used in the study, 

captan and thiram, have since been permitted for use to sterilize soils in the conduct of terrestrial plant 

studies; therefore the terrestrial plant effects data considered in this assessment now includes the 

results from corn and pea. Sugarbeet and cucumber seed were also treated with other unapproved 

compounds (e.g., Lindane), so they were not reconsidered in this assessment. 

Based on the available seedling emergence and vegetative vigor toxicity data (MRID 42647601), it 

appears that the vegetative vigor plant growth stage is most sensitive to fosamine ammonium 

(technical) (Table 2 and 3). At the seedling emergence stage, shoot height was impacted for several 

species, with onion and oilseed rape being the most sensitive taxa for monocots and dicots respectively 

(Table 2). 

Table 2. Terrestrial Plants Toxicity: Seedling Emergence for Fosamine Ammonium Technical (lb a.i./A)a

 

Species Endpoint NOEC IC05 IC25

Monocots 

Onion Shoot Height 3.0 0.86 3.55 

Corn Shoot Height 24 NC >24 

Wheat Shoot Height 24 NC >24 

Dicots 

Sorghum Shoot Height 3.0 3.18 11.6 

Soybean Shoot Height 6.0 2.61 8.86 

Pea Shoot Height 24 9.86 23.0 

Tomato Shoot Height 12 5.71 >24 

Oilseed Rape Shoot Height 1.5 0.61 2.29 a

 NC- not calculable; value either could not be computed or was not a realistic value. In cases where 

less than 25% effects were observed the corresponding IC25 value is represented as ‘greater than’ the 

highest concentration tested. 

Bolded values identify most sensitive taxon within monocots and dicots. 

Italicized values identify where the IC05 will be used in lieu of the NOEC 

Data are from MRID 42647601. 

At the vegetative vigor stage, the most sensitive species of monocots was corn with an IC25 of 0.383 lb 

a.i./A, and the most sensitive dicot was soybean with an IC25 of 0.0994 lbs a.i./A. EPA relied upon the 
5

IC05 for both of these species in the RQ calculations. For corn the NOAEC was statistically determined to 

be 0.375 lb a.i./A. 

Table 3. Terrestrial Plants Toxicity: Vegetative Vigor for Fosamine Ammonium Technical (lb a.i./A)a

 

Species Endpoint NOEC IC05 IC25

Monocots 

Onion Shoot Height 3.0 0.64 6.58 

Corn Total Weight 0.375 0.105 0.383 

Wheat Total Weight 1.5 0.699 1.865 

Dicots 

Sorghum Total Weight 0.750 0.73 1.63 

Soybean Total Weight <0.0938 0.0126 0.0994 

Pea Total Weight 1.5 NC >1.5 

Tomato Total Weight 1.5 0.830 2.125 

Oilseed Rape Total Weight 1.5 0.54 1.174 a

 NC- not calculable; value either could not be computed or was not a realistic value. In cases where 

less than 25% effects were observed the corresponding IC25 value is represented as ‘greater than’ the 

highest concentration tested. 

Bolded values identify most sensitive taxon within monocots and dicots. 

Italicized values identify where the IC05 will be used in lieu of the NOAEC 

Data are from MRID 42647601. 

Table 4. Estimated Risk Quotients for Plants and Endangered Terrestrial Plants for Ground and Aerial 

Application of Fosamine Ammonium 

Organism 

Ground Spray (24 lb a.i./A) Aerial Spray (12 lb a.i./A)

Adjacent 

uplands

Adjacent 

wetlands Drift Only Adjacent uplands

Adjacent 

wetlands Drift Only

Monocots 0.4 3.4 0.6 0.3 1.9 1.6

Listed 

Monocots 0.5 4.1 0.6 0.4 2.2 5.7 

Dicots 0.6 5.3 2.4 0.5 2.9 6.0 

Listed Dicots 1.0 8.2 19.0 0.8 4.4 47.6 

Bold values denote an exceedance of the LOC (=1.0) 

Results presented are based on the maximum single application rate and the endpoints for the most 

sensitive taxa presented in Tables 2 & 3. 

The distance from the application site where risk to terrestrial plant taxa are no longer of a concern 

following fosamine ammonium application is greater than 290 feet for all terrestrial plants when applied 

by air (Table 6). Coarser droplet spectra reduce the distances; however, for monocots such as corn, the 

most sensitive monocot tested, risk extends to 115 feet from the field’s edge, and for dicots such as 

soybean, risk extends to 318 feet. Listed species of dicots are at risk beyond 1000 feet (AgDrift 

maximum estimated distance = 995 ft) for all aerial and ground application scenarios. Applying by 

ground spray with coarser droplet sizes reduces the predicted drift distance greatly for monocots (from 
6

154 to 36 ft) but dicots continue to have RQs above the LOC at 194 ft and greater than 1000 for listed 

species for fine to medium/coarse droplets. 

Table 5. Estimated distance (feet) from the edge of the spray area to the most sensitive monocot or 

dicot species in the vegetative vigor stage of growth (AgDrift Tier-I)1

. 

Additional Terrestrial Plant Risk Characterization 

Open literature toxicity data for ‘target’ terrestrial plant species, which include efficacy studies, are not 

currently considered in deriving the most sensitive endpoint for terrestrial plants. Efficacy studies do not 

typically provide endpoint values that are useful for risk assessment (e.g., NOAEC, EC50, etc.), but rather 

are intended to identify a dose that maximizes a particular effect (e.g., EC100). However, there are 

several studies conducted on the efficacy of fosamine ammonium on various tree species at labeled 

rates, which are qualitatively considered here to inform on the potential for effects on 

underrepresented species (e.g., woody species) in the absence of registrant-submitted plant toxicity 

data using woody species. A study (Geyer, 1994) conducted in the context of typical rights-of-way 

vegetation management (e.g., including mechanical cutting of brush or trees along with herbicides) 

using a typical end-use product that contained fosamine ammonium (combined with a water softener 

and surfactant) demonstrated a reduction in height as well as percent resprouting when compared to 

the cut-only control stand. Treated species included American plum, black cherry, black locust, black 

walnut, boxelder, cottonwood, dogwood, elm, green ash, hackberry, mulberry, redbud, and red and 

white oak trees. While the magnitude of effects on woody species treated using products containing 

fosamine ammonium without prior cutting, sensitive woody species may be affected if exposed. 

Incidents 

As of September 2, 2015, the Ecological Incident Information System (EIIS, version 2.1), which is 

maintained by the Agency’s Office of Pesticide Programs, returned one terrestrial plant incident in 

Arkansas attributed to fosamine ammonium use with “possible” certainty, reporting damage to nearby 

crops (cantaloupe, tomato, and watermelon) from exposure to drift (Table 6). 

Organism 

Ground Spray (24 lbs a.i./A)2 Aerial Spray (12 lbs a.i./A) 

Very-Fine 

To Fine 

Fine to 

Medium/Coars

e 

Fine to 

Medium 

Medium to 

Coarse 

Coarse to 

Very Coarse 

Monocots 154 36 289 164 115 

Listed 

Monocots 157 36 295 167 115 

Dicots 482 194 >995 522 318 

Listed Dicots >995 >995 >995 >995 >995 

1 results presented are based on the maximum single application rate and the endpoints for the 

most sensitive taxa presented in Tables 2 & 3. 

2 ground application assumes a high-boom spray application method 
7

Table 6. Ecological Incidents Associated with Fosamine Ammonium 

Incident 

Number 

Taxa 

Involved Magnitude Year Location Use Legality of 

Use 

Certainty 

Category Residues 

Other 

Chemicals 

Involved 

I015280-

001 

Terrestrial 

Plant ~ 5 acres 2004 AR Rights of 

way 

Registered 

Use Possible None 

reported 

None 

reported 

No ecological incidents were reported in the IDS Aggregate Incident Reports’ database maintained by 

EPA. 

Clean Water Act

Fosamine ammonium is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act, based on information provided at 

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

In addition, no Total Maximum Daily Loads (TMDL) have been developed for fosamine ammonium, 

based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885

&p_pollutant_group_name=PESTICIDES. More information on impaired water bodies and TMDLs can be 

found at http://www.epa.gov/owow/tmdl/. 

Endangered Species 

Consistent with EPA’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate 

risks to federally listed threatened and endangered (listed) species from registered uses of pesticides in 

accordance with the Joint Interim Approaches developed to implement the recommendations of the 

April 2013 National Academy of Sciences (NAS) report, Assessing Risks to Endangered and Threatened 

Species from Pesticides. The NAS report outlines recommendations on specific scientific and technical 

issues related to the development of pesticide risk assessments that EPA and the Services must conduct 

in connection with their obligations under the ESA and FIFRA. EPA will address concerns specific to 

fosamine ammonium in connection with the development of its final registration review decision for 

fosamine ammonium. 

In November 2013, EPA, the U.S. Fish and Wildlife Service, National Marine Fisheries (the Services), and 

USDA released a white paper containing a summary of their joint Interim Approaches for assessing risks 

to listed species from pesticides. These Interim Approaches were developed jointly by the agencies in 

response to the NAS recommendations, and reflect a common approach to risk assessment shared by 

the agencies as a way of addressing scientific differences between the EPA and the Services. Details of 

the joint Interim Approaches are contained in the November 1, 2013 white paper, Interim Approaches 

for National-Level Pesticide Endangered Species Act Assessments Based on the Recommendations of the 

National Academy of Sciences April 2013 Report. 

 

Given that the agencies are continuing to develop and work toward implementation of the Interim 

Approaches to assess the potential risks of pesticides to listed species and their designated critical 

habitat, this ecological problem formulation supporting the Preliminary Work Plan for fosamine 

ammonium does not describe the specific ESA analysis, including effects determinations for specific 
8

listed species or designated critical habitat, to be conducted during registration review. While the 

agencies continue to develop a common method for ESA analysis, the planned risk assessment for the 

registration review of fosamine ammonium will describe the level of ESA analysis completed for this 

particular registration review case. This assessment will allow EPA to focus its future evaluations on the 

types of species where the potential for effects exists, once the scientific methods being developed by 

the agencies have been fully vetted. Once the agencies have fully developed and implemented the 

scientific methods necessary to complete risk assessments for listed species and their designated critical 

habitats, these methods will be applied to subsequent analyses of fosamine ammonium as part of 

completing this registration review. 

Endocrine Disruption Screening Program 

Fosamine ammonium was not included in the first group of 67 chemicals issued an order to conduct Tier 

1 EDSP testing. For additional information on the EDSP, visit http://www.epa.gov/endo/. 

References 

U.S. EPA, 1994. Fosamine Ammonium RED. Environmental Fate and Effects Division.

Geyer, W.A., et al. Woody Vegetation Control on Utility Rights-of-Way in Eastern Kansas: I. Management 

Techniques. Journal of Arboriculture 20(5): 282-286. September 1994. ECOTOX Ref. 116047. 

Marrs R.H. Studies on the conservation of lowland Calluna heaths. I. Control of birch and bracken and its 

effect on heath vegetation. Journal of Applied Ecology, 24, 163-175. 1987. ECOTOX Ref. 

 
9

APPENDIX A: TerrPlant v. 1.2.2 

Green values signify user inputs (Tables 1, 2 and 4). 

Input and output guidance is in popups indicated by red arrows. 

 

Table 1. Chemical Identity. 

Parameter User Inputs 

Chemical Name Fosamine Ammonium 

PC code 106701 

Use Airports 

Application Method Ground Spray 

Application Form Liquid 

Solubility in Water (ppm) 1790000 

 

Table 2. Input parameters used to derive EECs. 

Input Parameter Symbol Value (user inputs) Units 

Application Rate A 24 lbs a.i./A 

Incorporation I 1 none 

Runoff Fraction R 0.05 none 

Drift Fraction D 0.01 none 

 

Table 3. EECs for Fosamine Ammonium. Units in lbs a.i./A. 

Description Equation EEC 

Runoff to dry areas (A/I)*R 1.2 

Runoff to semi-aquatic areas (A/I)*R*10 12 

Spray drift A*D 0.24 

Total for dry areas ((A/I)*R)+(A*D) 1.44 

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 12.24 

 

Table 4. Plant survival and growth data used for RQ derivation. Units are in lbs a.i./A. All values are user 

inputs 

 Seedling Emergence Vegetative Vigor 

Plant type EC25 NOAEC EC25 NOAEC 

Monocot 3.55 3 0.383 0.375 

Dicot 2.29 1.5 0.0994 0.0126 

 

Table 5. RQ values for plants in dry and semi-aquatic areas exposed to Fosamine Ammonium through runoff 

and/or spray drift.* 

Plant Type Listed Status Dry Semi-Aquatic Spray Drift 

Monocot non-listed 0.4 3.4 0.6 

Monocot listed 0.5 4.1 0.6 

Dicot non-listed 0.6 5.3 2.4 

Dicot listed 1.0 8.2 19.0 

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group. 
APPENDIX B. SUMMARY OF AVAILABLE FATE AND TOXICITY DATA FOR FOSAMINE AMMONIUM

Table 1. Physical and Chemical Properties of Fosamine Ammonium 

Common name Fosamine Ammonium 

Chemical name ammonium ethyl carbamoylphosphonate Pesticide type herbicide Chemical class organophosphonate CAS number 25954-13-6 Empirical formula C3H11

O

N4 2P 

Molecular mass (g/mol) 170.11 Vapor pressure 4 x 10-6 mm Hg (25° C) 5.3 x 10-3 Pa (25° C) Henry’s Law Constant 5.04 x 10-7 PA m3/mol (calculated) Solubility in water 1,795,000 mg L-1 (20°C) 1,790,000 mg L-1 (25° C)1Kow 0.0012 (0.00104-0.00139) Melting Point 173-175q C (tech.) 1http://www.invasive.org/gist/products/handbook/13.Fosamine.pdf 

Table 2. Environmental Fate Data for Fosamine Ammonium 

Study/Current 

Guidelines Value Major Degradates1

/

Comments

MRID Classification 

Hydrolysis 

835.2120 0, Stable None 40133701 Acceptable 

Photodegradation 

in Water 

835.2240 

0, Stable None 40133702 Acceptable 

Photodegradation 

on Soil 

835.2410 

0, Stable None 40133703 Acceptable 
11

Laboratory 

Volatility 

835.1410 

<0.00631 

ʅŐͬĐŵ2/hour 

фϮϮʅŐͬŵ3

Fosamine ammonium (2% AR in soil) 

CPA (max 89% AR in soil) 

IN-G3003 (max 15% in soil) 

42492201 Acceptable 

Aerobic Soil 

Metabolism 

835.4100 

t1/2 = 0.5 to 12 days 

CPA (max 94% AR immediately 

posttreatment) 

t1/2 = 144 days 

IN-G3003 (max 26% AR at 1 month 

posttreatment) 

t1/2 = 34 days 

Total residue t1/2 = 204 days; observed 

DT50 = 220 

CO2 (max at 33% at study termination) 

42060601 

141554 Acceptable 

Anaerobic 

Aquatic 

Metabolism 

835.4400 

t1/2 = 2 days 

CPA (max 59% AR at 14 days 

posttreatment) 

t1/2 = 12 days 

ING-3003 (max 43% AR at 9 months 

posttreatment) 

CO2 (max at 7.6% at 12 months--study 

termination) 

42060602 42680701 42724301 

Acceptable 

Study/Current 

Guidelines Value MRID Classification 

Adsorption/ 

Desorption 

(Batch 

equilibrium) 

835.1230 

Soil Kd (mL/g) Koc (mL/g) KF(ad) (ʅg 1-1/n (cm3)1/n g -1) 1/n KFoc (ʅg 1-1/n (cm)1/n g -1) 

42492401 40133704 42492301

Acceptable 

New Jersey 

sandy loam > 1 8.087 0.066 0.8603 --- 

Woodstown 

sandy loam 0.14 13.249 0.14 0.98 13.249 

Cecil sandy 

loam 0.11 5.302 0.11 ~1 5.302 

Flanagan silt 

loam 0.11 2.645 0.11 ~1 2.645 
12

Study/Current 

Guidelines Value Major Degradates1/ Comments MRID Classification

Terrestrial Field 

Dissipation 

835.6100 

1 d Lexington, TN 1 d Newark, DE 5 d Fayetteville, NC 

Fosamine ammonium found predominantly in the 0 to 15 cm soil samples. CPA (max at 26.7% at six weeks, DE silt loam; max at 40% at six weeks, IL silt loam; and 83% at two weeks, FL sandy loam) 

40955701 Acceptable 

Fish BCF 

850.1730 

No accumulation observed therefore no BCF could be calculated. A 9% observed mortality. 42587601 Acceptable 

1 Major degradates are defined as those that >10% of the applied. 
13

Table 3. Aquatic Toxicity Profile for Fosamine Ammonium 

Study/Current 

Guidelines Taxon Exposure Duration Most Sensitive Species Tested Toxicity Value mg a.i./L Acute Toxicity Category1 MRID Classification/ Comments 

Fish Acute, 

Freshwater and Marine 

850.1075 

Freshwater Fish Acute Rainbow trout, Oncorhynchus mykiss LC50= 377 Practically nontoxic 41607103 Acceptable 

Fish Acute, 

Freshwater and Marine 

850.1075 

Estuarine/ 

Marine Fish Acute Sheepshead minnow, Cyprinodon variegatus LC50= >128 Practically nontoxic 42715101 Supplemental 

Aquatic Invertebrate 

Acute, 

Freshwater Daphnids 

850.1010 

Freshwater 

Invertebrates Acute Water Flea, Daphnia magna LC50= 1524 Practically nontoxic 00143492 and 92086005 Supplemental 

Mysid Chronic 

850.1350 

Estuarine/ 

Marine 

Invertebrates 

Acute Eastern oyster LC50 = >122 Practically nontoxic 42715102 Supplemental 

Algal Toxicity, 

Tiers I and II 

850.5400 

Non-vascular 

plant Tier I Alga, Skeletonema costatum EC25 = >15 NOAEC = 15 

Slightly toxic 

to 

practically 

nontoxic 

42902904 Acceptable 

Aquatic Plant Toxicity 

Test Using Lemna spp., 

Tiers I and II 

850.4400 

Vascular plant Tier I Duckweed, Lemna gibba EC50 = >21 (EC40 = 21) NOAEC = <21 Slightly toxic to practically nontoxic 42587602 Supplemental 

1Categories of acute toxicity for aquatic organisms (U.S. EPA, 2004) based on LC50 (mg/L): < 0.1 very highly toxic; 0.1-1 highly toxic; >1-10 

moderately toxic; >10-100 slightly toxic; >100 practically nontoxic. Toxicity categories for aquatic plants have not been defined. 
14

Table 4. Terrestrial Toxicity Profile for Fosamine Ammonium 

Guideline Taxon Exposure Duration Most Sensitive Species Tested Toxicity Value Acute Toxicity Category Classification MRID 

Mammal 

Acute 

850.2400 

Mammals 

Acute 

Rat 

Rattus norvegicus

Waived; LD50 >1954 mg 

a.i./Kg bw (adjusted for 

97.7% purity) from acute 

neurotoxicity study with no 

deaths up to HDT1 (2000 mg 

tech/kg bw)

Practically 

nontoxic Acceptable 42946501 

Chronic Rat R. norvegicus NOAEC = 200 mg/Kg/d LOAEC = 1000 mg/Kg/d N/A Supplemental 00075736 

Avian Acute 

Oral 

850.2100 

Birds 

Acute Oral 

Northern 

bobwhite quail 

(Colinus 

virginianus) 

Mallard 

(Anas 

platyrhynchos) 

Passerine 

LD50= >5000 mg/Kg bw 

LD50= >5000 mg/Kg bw 

none 

Practically 

nontoxic 

Practically 

nontoxic 

Supplemental 

Supplemental 

00130225 00093715 

Avian Dietary 

850.2200 

Sub-acute 

Dietary 

Quail and mallard 

(C. virginianus and

A. platyrhynchos) 

>5620 ppm diet Practically nontoxic Supplemental 41891602 41891603 

Avian 

Reproduction 

850.2300 

Chronic 

Reproduction 

Mallard 

A. platyrhynchos

NOAEC = 11,600 ppm 

LOAEC = >11,600 ppm 

(mg/Kg/d) 

Practically 

nontoxic Supplemental 44143501 

Honey Bee 

Acute Contact 

Toxicity 

850.3020 

Terrestrial 

Invertebrates Acute Honey Bee Apis mellifera LD50 = >200 ug a.i./bee Practically nontoxic Supplemental 41215802 

Terrestrial 

Plant Toxicity, 

Tier II 

Tier II – 

Seedling 

Emergence 

Rape, shoot 

length inhibition 

EC25 = 2.3 

EC50 = 5.8 NOAEL = 1.5 lb a.i./acre 

N/A 

All except 

sugarbeet 

acceptable 

42647601 
15

850.4100 850.4150 

Vegetative 

Vigor 

Soybean, total 

weight inhibition 

EC25 = 0.099 

EC50 = 0.42 NOAEL = <0.094 lb a.i./acre 

43651101 

1 HDT = highest dose tested.