Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart)

Pest Management Regulatory Agency
31 October 2012
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2012-26E-PDF (PDF version)

Summary

Table of Contents

• Proposed Registration Decision for Mono- and Di-Potassium Salts of Phosphorous Acid
• What Does Health Canada Consider When Making a Registration Decision?
• What Are Mono- and Di-Potassium Salts of Phosphorous Acid?
• Health Considerations
• Environmental Considerations
• Value Considerations
• Measures to Minimize Risk
• Next Steps
• Other Information

Proposed Registration Decision for Mono- and Di-Potassium Salts of Phosphorous Acid

Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the  Pest Control Products Act and  Regulations, is proposing full registration for the sale and use of Rampart Technical and Rampart Fungicide, containing the technical grade active ingredient mono- and di-potassium salts of phosphorous acid, to control late blight and pink rot on post‑harvest potatoes and to suppress downy mildew in brassica leafy vegetables and grapes.

An evaluation of available scientific information found that, under the approved conditions of use, the product has value and does not present an unacceptable risk to human health or the environment.

This summary describes the key points of the evaluation, while the Science Evaluation of Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart) provides detailed technical information on the human health, environmental and value assessments of Rampart Technical and Rampart Fungicide.

What Does Health Canada Consider When Making a Registration Decision?

The key objective of the Pest Control Products Act is to prevent unacceptable risks to people and the environment from the use of pest control products. Health or environmental risk is considered acceptable if there is reasonable certainty that no harm to human health, future generations or the environment will result from use or exposure to the product under its proposed conditions of registration. The Act also requires that products have value when used according to the label directions. Conditions of registration may include special precautionary measures on the product label to further reduce risk.

To reach its decisions, the PMRA applies modern, rigorous risk-assessment methods and policies. These methods consider the unique characteristics of sensitive subpopulations in humans (for example, children) as well as organisms in the environment (for example, those most sensitive to environmental contaminants). These methods and policies also consider the nature of the effects observed and the uncertainties when predicting the impact of pesticides. For more information, please refer to the following:

• Protecting Your Health and the Environment
• Pesticide Registration Process
• Pesticide Risk Reduction Program

Before making a final registration decision on mono- and di-potassium salts of phosphorous acid, the PMRA will consider all comments received from the public in response to Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart). The PMRA will then publish a Registration Decision on mono- and di‑potassium salts of phosphorous acid, which will include the decision, the reasons for it, a summary of comments received on the proposed final registration decision and the PMRA's response to these comments.

For more details on the information presented in this summary, please refer to the Science Evaluation in Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart).

What Are Mono- and Di-Potassium Salts of Phosphorous Acid?

Mono- and di-potassium salts of phosphorous acid are fungicide active ingredients belonging to Group 33 as designated by the Fungicide Resistance Action Committee and are classified as phosphonates. The mode of action of phosphorous acid involves the induction of host plant resistance and the inhibition of energy metabolism in susceptible fungal pathogens. Mono- and di-potassium salts of phosphorous acid are the active ingredients contained in Rampart Fungicide.

Health Considerations

Can Approved Uses of Mono- and Di-Potassium Salts of Phosphorous Acid Affect Human Health?

Mono- and di-potassium salts of phosphorous acid are unlikely to affect human health when used according to label directions.

Exposure to mono- and di-potassium salts of phosphorous acid may occur when handling and applying the product. When assessing health risks, two key factors are considered:

• the levels where no health effects occur and
• the levels to which people may be exposed.

The dose levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.

Mono- and di-potassium salts of phosphorous acid are of low toxicity by the oral, dermal and inhalation routes, mildly irritating to the eyes, non-irritating to the skin, and are not a dermal sensitizer. The available information suggests that it is unlikely to have any short-term or prenatal developmental effects, as well as any significant genotoxic effects. The precautionary label statement indicating that contact with skin, eyes, and clothing must be avoided, and the personal protective equipment statement that applicators and other handlers must wear a long‑sleeved shirt, long pants, gloves, shoes plus socks, and protective eyewear are effective mitigative measures to reduce the risk associated with the use of mono- and di-potassium salts of phosphorous acid.

Residues in Water and Food

Dietary risks from food and water are not of concern.

Dietary risk to humans is considered negligible based on a long history of use and the low toxicity of the end use product. The available literature suggests that there is no toxicological concern from ingestion of the end-use product residues.

It is anticipated that the proposed uses of mono- and di-potassium salts of phosphorous acid in Canada on food crops will not pose a risk to any segment of the population, including infants, children, adults and seniors, from consumption of produce from treated crops. In the United States, phosphorous acid has been designated Generally Regarded As Safe (GRAS) and the potassium salts of phosphoric acid have been exempted from the requirement of tolerance in and on all food commodities when used as an agricultural fungicide on food crops. The  United States Environmental Protection Agency (USEPA) introduced an initiative whereby an exemption from the requirement of tolerance was established for ammonium, sodium, and potassium salts of phosphorous acid on all food commodities to permit post-harvest application to stored potatoes at 35 600 ppm or less of phosphorous acid.

No risk due to exposure from drinking water is anticipated as the end-use product is not to be applied near or directly to water and is likely to be degraded in the environment.

Occupational Risks From Handling Rampart Fungicide

Occupational exposure to individuals mixing, loading, or applying Rampart Fungicide is not expected to result in unacceptable risk when the end-use product is used according to label directions.

Precautionary (for example, wearing of personal protective equipment) and hygiene statements on the label are considered adequate to protect individuals from occupational exposure. Since the application is done by commercial applicators, exposure to bystanders is expected to be negligible.

Environmental Considerations

What Happens When Mono- and Di-Potassium Salts of Phosphorous Acid Are Introduced Into the Environment?

Mono- and di-potassium salts of phosphorous acid are not expected to pose a risk to the environment when used as a fungicide.

Mono- and di-potassium salts of phosphorous acid will enter the environment when used as a fungicide on brassica leafy vegetables, grapes and potatoes in storage. Mono- and di-potassium salts of phosphorous acid produce phosphite ions when in contact with water. Over time, in soil, phosphite ions can be directly taken up by plant roots, slowly transform to phosphate (a plant nutrient), or bind with other substances in the soil. When phosphite ions get into lakes and rivers, it is expected that the phosphite will remain in the water phase. Phosphorous, in the form of phosphite, is not expected to be used by aquatic plants as a nutrient, but there is evidence that it could be used by certain kinds of bacteria. Mono- and di-potassium salts of phosphorous acid are not expected to accumulate in fish or other animals. It is also not expected that mono- and di‑potassium salts of phosphorous acid will pose a risk to non-target terrestrial and aquatic species given its low toxicity to these organisms.

Value Considerations

What Is the Value of Rampart Fungicide?

Rampart Fungicide is a non-conventional fungicide that controls potato late blight and pink rot when applied as a post-harvest treatment on potatoes. Foliar applications of Rampart Fungicide also suppress downy mildew on grape and brassica leafy vegetables.

Rampart Fungicide is a fully systemic product with a low risk of pest resistance development. These characteristics make it a valuable option for integration into spray programs.

Measures to Minimize Risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human and environmental health. These directions must be followed by law.

The key risk-reduction measures being proposed on the label of Rampart Fungicide to address the potential risks identified in this assessment are as follows.

Key Risk-Reduction Measures

Human Health

The statement, "CAUTION - EYE IRRITANT" is required on the principal display panel of the end-use product label. Moreover, other precautionary statements on the end-use product label, such as: "Avoid breathing vapors or spray mist, avoid contact with eyes, skin or clothing; remove contaminated clothing and wash clothing before use; applicators and/or other handlers must wear protective eyewear, long pants and long sleeved shirt, waterproof gloves, and shoes plus socks," should be effective in minimizing the potential for exposure.

Next Steps

Before making a final registration decision on mono- and di-potassium salts of phosphorous acid, the PMRA will consider all comments received from the public in response to Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart). The PMRA will accept written comments on this proposal up to 45 days from the date of publication of Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart). Please forward all comments to Publications. The PMRA will then publish a Registration Decision, which will include its decision, the reasons for it, a summary of comments received on the proposed final decision and the Agency's response to these comments.

Other Information

When the PMRA makes its registration decision, it will publish a Registration Decision on mono- and di-potassium salts of phosphorous acid (based on the Science Evaluation of this Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart)). In addition, the test data referenced in Proposed Registration Decision PRD2012-26, Mono- and Di-Potassium Salts of Phosphorous Acid (Rampart) will be available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa).