**UNITED STATES ENVIRONMENTAL PROTECTION AGENCY**

**MEMORANDUM SUBJECT**  : Summary

of e cotoxicity potassium phosphate, & potassium phosphate) in relation to the Review Scoping Document **Registration Review Case #: PC Code:**  **CAS #: Che**  **mi cal Class:** 

**FROM** : Miachel Rexrode, Ph.D., Senior Biologist

Biochemical Pesticides Branch Biopesticide & Pollution Prevention Division (7511P) **TO:** Leonard Cole,

Biochemical Pesticides Branch Biopesticide & Pollution Prev **ACTION REQUESTED** The following is the ecotoxicity assessment for phosphoric acid salts Registration Review Scoping Document **RECOMMENDATIONS AND CONCLUSIONS Executive Summary**  Based on the available information for need for additional ecotoxicity data for a new risk assessment and has exposure data on th ese chemical s

**UNITED STATES ENVIRONMENTAL PROTECTION AGENCY**

**WASHINGTON, D.C. 20460**

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION **MEMORANDUM September 1**  **4 , 2012**  cotoxicity risk assessment for phosphoric acid salts (iron phosphate, potassium phosphate, & potassium phosphate) in relation to the for Review Scoping Document **Registration Review Case #:** 6027 034903, 076413, 176407 10045 - 86 - 0, 7778 - 77 - 0, 7758 - 11 - 4 Biochemical s Miachel Rexrode, Ph.D., Senior Biologist /s/ 09/1 Biochemical Pesticides Branch Biopesticide & Pollution Prevention Division (7511P) Leonard Cole, Regulatory Action Leader /s/ 09/1 Biochemical Pesticides Branch Biopesticide & Pollution Prev ention Division (7511P) The following is the ecotoxicity assessment for phosphoric acid salts in support of Scoping Document . **RECOMMENDATIONS AND CONCLUSIONS** Based on the available information for phosphoric acid salts the Agency does not foresee the data for a new risk assessment and has waived all s . The se active ingredients are natural ly occurring, have a non OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

**, 2012** phosphoric acid salts (iron phosphate,

for Registration

/s/ 09/1 4 /2012 /s/ 09/1 4 /2012

in support of the

the Agency

does not foresee the waived all h azard and ly occurring, have a non -toxic mode of action, and are of low toxicity . There is reasonable certainty of no harm to the

non - target species from exposure to these chemicals in pesticide products when they are used according to label instructions. Environm ental hazard and fate data requirements for the Registration Review of Phosphoric Acid Salts have been full y satisfied for this Scoping document . An evaluation of risk to endangered/ threatened species will be completed for the final registration review. **Background Phosphoric Acid Salts**  **I ron (ferric)**  **phosphate** ( **034903)** is used in controlling snails and slugs on food crops and ornamentals at outdoor and indoor sites. Iron phosphate is a common chemical with a variety of uses, including as a human nutritional supplement and as an ingredient in fertilizer. Itis applied to soil as part of a pellet that also contains bait to attract snails and slugs. When the pests eat the pellets, the iron phosphate interferes with calcium metabolism in their gut, causing the snails and slugs to stop eating almost immediately resulting in de ath three to six day s later (Iron Phosphate Fact Sheet, 2001) . Iron (ferric) phosphate was first registered by the Agency

in 1997. There are currentl y four registered products containing the active ingredient. All four products are end - use products (EPs). Iron phosphate is the sole active ingredient in three of the products. Spinosad is an additional active ingredient for one of the products. The re are no currently approved uses for this chemical as an inert ingredient in pesticide products. The maximum application rate is 0.5

– 1.0 lbs ai/1000 sq ft. **P otassium phosphate**  **(076413)** is used as a fungicide against powdery mildew on food crops. It does have a toxic mode of action, so is therefore not classified as a biochemical. However, it is el igible for reduced data requirements because of its simple structure and natural occurrence (Potassium Phosphate Fact Sheet, 2009). Potassium phosphate was first registered by the Agency in 1998. There are currently four registered products containing the active ingredient. All four products are EPs. Potassium phosphate is not the sole active ingredient in these products. Mono and di - potassium salts of phosphorous acid or sulfur are additional active ingredient for the products. **D ipotassium phosphate**  **( 176407)**  is also used as a fungicide against a broad spectrum of diseases including powdery mildew, leaf spot, root dot, downy mildew, etc. on turf, ornamentals, and non - bearing fruit and nut tree crops. Itappears to have a mixed mode of action involving direct toxicity

to the pathogen, aided by a boosting of the plant’s defense mechanisms due to the fertilizing propert ies of the compound (Dipotassium Phosphate Fact Sheet, 2002) . Dipotassium phosphate was first registered b y the Agency in 2002. There is currentl y one registered product containing the active ingredient. This product is an EP. Dip otassium phosphate is not the sole active ingredient in this product . Mono - and di - potassium salts of phosphorous acid are the additional active ingredients for th e product. The re are no currentl y approved uses for this chemical as an inert ingredient in pesticide products.**Ecological Effects**

**Iron (ferric) phosphate** As a pesticide active ingredient, iron phosphate is used in controlling snails and slugs on food crops and ornamentals at outdoor and indoor sites. Iron phosphate is a common chemical with a variety of uses, including as a human nutritional supplement and as an ingredient in fertilizer. The substance is not harmful to humans, to other non - target organisms, or to the environment. It is an alternative to a more toxic chemical that has been used for controlling snails and slugs. Iron phosphate is applied to the soli as granular bait (0.5

– 1 lb ai/1000 sq ft ; 2.4 - 4.9 g/ m 2 ). Use sites include **f**

ood crops, ornamentals, lawns and gardens, and greenhouses . **Assessing Risks to the Environment** Snails and slugs are more sensitive to the effects of iron phosphate than are other organisms. No toxicity was seen in mammals (LD 50 > 5,000 mg/kg) , birds, or f ish. For several other organisms, including earthworms and certain ground beetles, no harmful effects are expected if users follow the application rates and use directions on the label. A study ( Kuhner, 1996 ) conducted on ground beetles (

Poecilus cupreus L ) found that tested application rate of 10 g/m2 iron phosphate showed no effect under field conditions. A reproduction study conducted on Rove Beetles ( Aleocharu bilineata Gyll) also found no effects after iron phosphate exposure of 10 g/m2 for 14 day s (Almond 1996 ). Wachter (1996), t est ed earthworms ( Eisenia fetida ) using artificial soil and found LC 50 >1,000 mg/kg after exposure to iron phosphate . The exposure of non - target insects and earthworms to iron phosphate use as snail bait will not result in t oxic risk . The t ested application rate of 10 g/m 2 showed no effect and is twice the level of the registered maximum application rate (4.9 g/m 2 ) (Risk Quotient = 0.0). **Endangered Species** Environmental hazard and fate data requirements for the Registration Review of Phosphoric Acid Salts have been full y satisfied for this Scoping document . An evaluation of risk to endangered/ threatened species will be completed for the final registration review. **Potassium Phosphate** Potassium phosphate is naturally occurring, has had widespread use with no adverse effects, but has a toxic mode of action on fungi . This compound does not share an y common mechanisms of toxicity with othe r pesticide active ingredients and is used as an agricultural fertilizer and a buffe ring agent in pesticide formulations. There are no reported adverse effects from these uses and toxicology

studies submitted indicated low mammalian toxicity (rat LD 50 > 5,000 mg/kg) . Therefore, no impact on the potential for toxic effects from the pestici dal use is expected when added to the other uses of potassium phosphate. Data waivers for ecological effects studies were requested and supported based on the current use as a pesticide inert ingredient and fertilizer, and low acute mammalian toxicity . In addition, potassium phosphate is ubiquitous in nature, and no adverse effects have been reported on nontarget species with current uses. Risk to n ontarget species is minimal due to the use pattern,application methods, and mitigation of nontarget aquatic organism toxicity with appropriate precautionary

label statements under "Environmental Hazards." **Endangered Species** Environmental hazard and fate data requirements for the Registration Review of Phosphoric Acid Salts have been full y satisfied for this Scoping document . An evaluation of risk to endangered/ threatened species will be completed for the final registration review. **Dipotassium Phosphate** Dipotassium phosphate is commonly used as a foliar fertilizer. There have been no adverse ecological effects noted from its usage as a fertilizer. As a result, the data requirements for nontarget organisms were waived. A ccording to the Mineral Acids Red (dated December, 1993), phosphoric acid (and its salts) generally dissociates and releases hydrogen ions in the environment. As a result, risk to nontarget organisms is expected to be minimal. BPPD believes that the use of dipotassium phosphate according to label use directions should result in no significant adverse effects to wildlife. **Endangered Species** Environmental hazard and fate data requirements for the Registration Review of Phosphoric Acid Salts have been full y satisfied for this Scoping document . An evaluation of risk to endangered/ threatened species will be completed for the final registration review.

**References** Almond, D.S. 1996. NEU 1165M Acute toxicity to the Rove Beetle (

Aleocharu bilineata Gyll) in the laboratory . ( MRID# 44171602 ) Kuhner, C. 1996. NEU 1165M: Acute toxicity to the Ground Beetle (

Poecilius cupreus L .) in the Laboratory . ( MRID# 44171601 ) U.S. EPA Biochemical Fact Sheet for Iron Phosphate. Issued January , 2001. <http://www.epa.gov/opp00001/chem_search/reg_actions/regis tration/fs_PC - 034903_01 - Mar - 01.pdf > U.S. EPA Biochemical Fact Sheet for Potassium Phosphate. Issued January , 2001. <http://www.epa.gov/opp00001/chem_search/reg_actions/registration/fs_PC - 076413_25 - Nov - 09.pdf > U.S. EPA Biopesticides Registration Action D ocument (BRAD) for Dipotassium Phosphate . Issued March , 2003.<http://www.epa.gov/opp00001/chem_search/reg_actions/registration/decision_PC 176407_23 - Mar - 03.pdf

> Wachter, S. 1996. Acute toxicity of NEU 1165M on earthworms (Eisenia fetida) using artificial soil testing. (MRID # 4417160 3)