Proposed Registration Decision PRD2021-01, Indole-3-butyric acid, Calcium Disodium EDTA hydrate, VNT MFG, and VNT Selective Herbicide Ready-to-Use

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Summary

This page is a summary of the consultation document. If you would like to comment, please request the full consultation document.

To obtain a full copy of Proposed Registration Decision PRD2021-01, Indole-3-butyric acid, Calcium Disodium EDTA hydrate, VNT MFG, and VNT Selective Herbicide Ready-to-Use please contact our publications office.

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Table of Contents

Proposed registration decision for Indole-3-Butyric Acid and Calcium Disodium EDTA Hydrate

Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the Pest Control Products Act, is proposing registration for the sale and use of Intelligro IBA Technical, containing the technical grade active ingredient indole-3-butyric acid, Intelligro Calcium Disodium EDTA Technical, containing the technical grade active ingredient calcium disodium ethylenediaminetetraacetic acid (EDTA) hydrate, the manufacturing concentrate VNT MFG and the end-use product VNT Selective Herbicide Ready-to-Use, containing the technical grade active ingredients indole-3-butyric acid and calcium disodium EDTA hydrate for control of broadleaf weeds and moss on turf.

An evaluation of available scientific information found that, under the approved conditions of use, the health and environmental risks and the value of the pest control products are acceptable.

This summary describes the key points of the evaluation, while the Science Evaluation of Proposed Registration Decision PRD2021-01, Indole-3-butyric acid, Calcium Disodium EDTA hydrate, VNT MFG, and VNT Selective Herbicide Ready-to-Use provides detailed technical information on the human health, environmental and value assessments of indole-3-butyric acid, calcium disodium EDTA hydrate, VNT MFG and VNT Selective Herbicide Ready-to-Use.

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. 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:

Before making a final registration decision on indole-3-butyric acid, calcium disodium EDTA hydrate, VNT MFG and VNT Selective Herbicide Ready-to-Use, Health Canada's PMRA will consider any comments received from the public in response to PRD2021-01. Health Canada will then publish a Registration Decision on indole-3-butyric acid, calcium disodium EDTA hydrate, VNT MFG and VNT Selective Herbicide Ready-to-Use, which will include the decision, the reasons for it, a summary of comments received on the proposed registration decision and Health Canada's response to these comments.

For more details on the information presented in this summary, please refer to the Science Evaluation of PRD2021-01.

What is Indole-3-butyric Acid and Calcium Disodium EDTA Hydrate?

Indole-3-butyric acid (IBA) is a naturally occurring auxin, which is a plant hormone. IBA primarily promotes lateral/adventitious root formation in the plants. When IBA is administered to plants at higher concentrations, it causes uncontrolled cell division and abnormal growth, which may lead to death of susceptible plants.

Calcium disodium EDTA hydrate (CaNa2 EDTA) is a chelating agent, which may act both as a penetrant to improve uptake of IBA and to counteract the destruction of IBA during auxin conjugation and transport in the plant cells.

Health considerations

Can approved uses of Indole-3-Butyric Acid and Calcium Disodium EDTA Hydrate affect human health?

Indole-3-butyric acid and calcium disodium EDTA hydrate, are unlikely to affect your health when used according to label directions.

Potential exposure to indole-3-butyric acid (IBA) and calcium disodium ethylenediaminetetraacetic acid (EDTA) hydrate (CaNa2 EDTA) may occur when handling or applying the product. When assessing health risks, two key factors are considered:

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

Toxicology studies in laboratory animals describe potential health effects from varying levels of exposure to a chemical and identify the dose where no effects are observed.

In laboratory animals, the technical grade active ingredient, indole-3-butyric acid, was of low acute toxicity by the oral and dermal routes of exposure and moderately irritating to eyes. A request to waive dermal irritation testing was accepted based on the lack of irritation noted in the short-term dermal toxicity study. Acute inhalation toxicity testing demonstrated that indole-3-butyric acid cannot be generated into particles that could be inhaled, and as a result, acute inhalation toxicity is considered to be low. A waiver for dermal sensitization testing was accepted based on published scientific literature and Quantitative Structure Activity Relationship [(Q)SAR] model predictions. Indole-3-butyric acid is not considered to be a dermal sensitizer.

Short-term dermal toxicity testing, prenatal developmental toxicity testing, and information from published scientific literature were assessed for the potential of indole-3-butyric acid to cause short-term toxicity, developmental toxicity, genotoxicity, and various other effects. Treatment related adverse effects in animals administered repeated high doses of indole-3-butyric acid were not observed. In pregnant animals, exposure to indole-3-butyric acid resulted in reduced fetal body weight and increased incidence of skeletal variations. There was an indication that the young were more sensitive than the adult animal. There was no indication of genotoxicity or mutagenicity for indole-3-butyric acid.

In laboratory animals, the technical grade active ingredient, calcium disodium EDTA hydrate, was of low acute toxicity by the oral, dermal and inhalation routes and slightly irritating to skin. Publicly available information and published scientific literature were considered acceptable to waive eye irritation and dermal sensitization testing. Calcium disodium EDTA hydrate is considered to be severely irritating to the eyes and a potential dermal sensitizer.

Short-term dermal toxicity testing, prenatal developmental toxicity testing as well as information from published scientific literature were assessed for the potential of calcium disodium EDTA hydrate to cause short-term toxicity, developmental toxicity, genotoxicity, and various other effects. Adverse effects in animals given repeated high doses of calcium disodium EDTA hydrate included damage to coronary blood vessels and lesions in esophagus, trachea, and pharynx, and effects in the kidneys of males. However, these effects were not seen in other published repeat dose studies with EDTA and related compounds. In pregnant animals, exposure to calcium disodium EDTA hydrate resulted in an increase in skeletal variations in the fetus consistent with effects expected from the zinc-chelating effects of EDTA. Based on surrogate studies from published scientific literature on calcium disodium EDTA, trisodium EDTA and disodium EDTA, calcium disodium EDTA hydrate is not considered genotoxic or mutagenic.

In laboratory animals, the end-use product, VNT Selective Herbicide Ready-to-Use, was of low toxicity by the oral, dermal and inhalation routes, minimally irritating to eyes, non-irritating to skin and not a dermal sensitizer. The toxicological profile of the manufacturing concentrate, VNT MFG, is equivalent to the toxicological profile of the end-use product.

The risk assessment protects against the findings noted above as well as any other potential effects by ensuring that the level of human exposure is well below the lowest dose at which these effects occur in animal studies.

Residues in water and food

Dietary risks from food and water are acceptable.

VNT Selective Herbicide Ready-to-Use is not proposed for food or feed uses. In addition, the likelihood of residues of indole-3-butyric acid and calcium disodium EDTA hydrate in drinking water will be low. Consequently, health risks from dietary exposure are acceptable for all segments of the population, including infants, children, adults and seniors.

Risks in residential and other non-occupational environments

Estimated risk for residential and other non-occupational exposure is acceptable.

VNT Selective Herbicide Ready-to-Use is proposed for use as a domestic, spot treatment herbicide to control weeds in residential lawns. The product label for VNT Selective Herbicide Ready-to-Use will include measures to minimize bystander exposure such as not applying when people are present, reducing spray drift, not allowing access to the treated area until after sprays have dried, and ensuring that applicators limit non-target application.

Residential and non-occupational exposure to VNT Selective Herbicide Ready-to-Use is therefore expected to be low when label directions are observed. Consequently, the risk to residents and the general public is acceptable.

Occupational risks from handling VNT Selective Herbicide Ready-to-Use

Occupational risks are not applicable when VNT Selective Herbicide Ready-to-Use is used according to the label directions, which includes protective measures.

Since VNT Selective Herbicide Ready-to-Use is a domestic product, occupational risks are not applicable.

Environmental considerations

What happens when indole-3-butyric acid and calcium disodium EDTA hydrate are introduced into the environment?

When used according to label directions, risks associated with indole-3-butyric acid and calcium disodium EDTA hydrate and associated end-use product are acceptable from the viewpoint of environmental protection.

The product containing indole-3-butyric acid and calcium disodium EDTA hydrate is formulated as a ready-to-use product and is applied as a spot treatment for direct application using a handheld application equipment (plastic jug fitted with a spray trigger) to target weeds and moss on residential lawns, until foliage is thoroughly wetted, or just to the point of runoff, while minimizing contact with the surrounding turf. As such, environmental releases are expected to be minimal and a quantitative risk assessment was not conducted. The environmental risks associated with the end-use product are acceptable when used according to label directions.

Value considerations

What is the value of VNT Selective Herbicide?

VNT Selective Herbicide provides control, suppression, or partial suppression of several broadleaf weeds and moss on residential lawns.

VNT Selective Herbicide, containing 1.25% IBA and 2% CaNa2 EDTA, is formulated as a ready-to-use product for spot treatment on lawns. Application of VNT Selective Herbicide provides control, suppression, or partial suppression of numerous broadleaf weeds and moss.

VNT Selective Herbicide is a non-conventional herbicide that will serve as an alternative option for broadleaf weed and moss management on residential lawns.

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 Intelligro IBA Technical, Intelligro Calcium Disodium EDTA Technical, VNT MFG, and VNT Selective Herbicide Ready-to-Use to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures

Human health

People and pets are not allowed to enter lawns that have been treated with VNT Selective Herbicide Ready-to-Use until the sprays have dried.

The signal words "WARNING- EYE IRRITANT" are required on the principal display panel of the label for Intelligro IBA Technical. Standard hazard and precautionary statements are also required on the technical grade active ingredient label to inform workers of the eye irritation potential of the product.

The signal words "DANGER- EYE IRRITANT" and "POTENTIAL SENSTIZER" are required on the principal display panel of the label for Intelligro Calcium Disodium EDTA Technical. Standard hazard and precautionary statements are also required on the technical grade active ingredient label to inform workers of the eye irritation and potential for sensitization of the product.

Standard hazard and precautionary statements are required on the end-use product label to address exposure to individuals in residential areas.

Environment

Precautionary label statements will be required to direct users to avoid contact with non-target terrestrial plants and when rain is forecast. Direct application of indole-3-butyric acid and calcium disodium EDTA hydrate to water is not allowed.

Next steps

Before making a final registration decision on indole-3-butyric acid, calcium disodium EDTA hydrate, VNT MFG and VNT Selective Herbicide Ready-to-Use, Health Canada's PMRA will consider any comments received from the public in response to PRD2021-01. Health Canada will accept written comments on PRD2021-01 up to 45 days from the date of publication of PRD2021-01. Please forward all comments to Publications. Health Canada will then publish a Registration Decision, which will include its decision, the reasons for it, a summary of comments received on the proposed decision and Health Canada's response to these comments.

Other information

When the Health Canada makes its registration decision, it will publish a Registration Decision on indole-3-butyric acid, calcium disodium EDTA hydrate, VNT MFG and VNT Selective Herbicide Ready-to-Use (based on the Science Evaluation of PRD2021-01). In addition, the test data referenced in this consultation document will be available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa).

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