Proposed Re-evaluation Decision PRVD2024-01, S-metolachlor and R-enantiomer and its associated end-use products

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Pest Management Regulatory Agency
29 February 2024
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2024-1E-PDF (PDF version)

Summary

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Table of contents

Proposed re-evaluation decision for S-metolachlor and R-enantiomer and associated end-use products

Under the authority of the Pest Control Products Act, all registered pesticides must be re-evaluated by Health Canada's Pest Management Regulatory Agency (PMRA) to ensure that they continue to meet current health and environmental standards and continue to have value. The re-evaluation considers data and information from pesticide manufacturers, published scientific reports and other regulatory agencies. Health Canada applies internationally accepted risk assessment methods as well as current risk management approaches and policies.

S-metolachlor and R-enantiomer (henceforth referred to as S-metolachlor) is a herbicide registered for use on major field crops, vegetables, fruit trees, forests, woodlots and outdoor ornamentals. It can be applied pre-plant surface (up to 30 days prior to planting), pre-plant incorporated, pre-emergent or post-emergent to control yellow nutsedge, annual grasses and broadleaved weeds. S-metolachlor products are formulated as emulsifiable concentrate or emulsion, suspension or solution or microcapsule suspension. It can be applied once per year using ground equipment only. Currently registered products containing S-metolachlor can be found in the Pesticide Product Information Database and in Appendix I of the full version of Proposed Re-evaluation Decision PRVD2024-01, S-metolachlor and R-enantiomer and Its Associated End-use Products. Appendix II of PRVD2024-01 lists all commercial uses for which S-metolachlor is presently registered.

This document (PRVD2024-01) presents the proposed re-evaluation decision for S-metolachlor, including the proposed amendments (risk mitigation measures) to protect human health and the environment, as well as the science evaluation on which the proposed decision is based. All products containing S-metolachlor that are registered in Canada are subject to this proposed re-evaluation decision. PRVD2024-01 is subject to a 90-day public consultation period,Footnote 1 during which the public (including the pesticide manufacturers and stakeholders) may submit written comments and additional information to PMRA Publications. The final re-evaluation decision will be published after taking into consideration the comments and information received during the consultation period.

Proposed re-evaluation decision for S-metolachlor and R-enantiomer

Under the authority of the Pest Control Products Act and based on an evaluation of available scientific information, Health Canada is proposing continued registration of most uses of S-metolachlor and associated end-use products registered for sale and use in Canada.

With respect to human health, potential risks from dietary (food and drinking water), occupational, and non-occupational exposure were shown to be acceptable when S-metolachlor is used according to proposed conditions of registration which includes additional risk mitigation measures as identified below.

Based on available scientific information, potential risks to the environment were shown to be acceptable when S-metolachlor is used according to proposed conditions of registration, which includes additional risk mitigation measures, as identified below.

S-metolachlor has value as a herbicide for managing grass and broadleaved weeds in many crops including field corn, soybeans, potatoes, fruit trees and vegetables. It is a key component in programs for controlling weeds in field corn. It is also one of the herbicides that controls yellow nutsedge in several crops, a troublesome weed which is difficult to manage due to its large root system and tolerance to cultivation and environmental stresses. S-metolachlor has variable application timing and use rates for several crops, especially field corn, allowing for flexibility under different local environmental, climatic and agronomic needs.

Risk mitigation measures

Registered pesticide product labels include specific directions for use. Directions include risk mitigation measures to protect human health and the environment and must be followed by law. The proposed label amendments as a result of the re-evaluation of S-metolachlor, are summarized below. Refer to Appendix VIII of PRVD2024-01 for details.

Human Health

As a result of the re-evaluation of S-metolachlor, the Health Canada is proposing further risk-reduction measures in addition to those already present on the product labels. Additional revisions to the S-metolachlor labels are also proposed to meet the current labelling standards.

To protect human health, the following risk mitigation measures are proposed:

Label improvements to meet current standards:

Environment

To protect the environment, the following risk mitigation measures are proposed:

Label improvements to meet current standards:

International context

S-metolachlor is currently acceptable for use in other Organisation for Economic Co-operation and Development (OECD) member countries, including the United States, New Zealand European Union, and Australia. In January 2024, the European Union published a non-renewal decision for S-metolachlor. Health Canada is currently reviewing the information related to the European Union decision, and will take appropriate action if there are reasonable grounds to believe that use of the products containing S-metolachlor results in unacceptable risks to human health or the environment.

No decision by an OECD member country to prohibit all uses of S-metolachlor for health or environmental reasons has been identified as of 13 November 2023.

Next steps

Upon publication of this proposed re-evaluation decision, the public, including the registrants and stakeholders are encouraged to submit additional information that could be used to refine risk assessments OR comments during the 90-day public consultation period.

All comments received during the 90-day public consultation period will be taken into consideration in preparation of re-evaluation decision documentFootnote 2, which could result in revised risk mitigation measures. The re-evaluation decision document will include the final re-evaluation decision, the reasons for it and a summary of comments received on the proposed re-evaluation decision with Health Canada's responses.

Refer to Appendix I of PRVD2024-01 for details on specific products impacted by this proposed decision.

Other information

The relevant confidential test data on which the proposed decision is based (as listed in the reference list of PRVD2024-01) are available for public inspection, upon application, in PMRA's Reading Room. For more information, please contact Health Canada's Pest Management Information Service.

Additional scientific information

No additional scientific data are being requested. However, feedback is sought regarding the following aspect of the proposed decision:

Footnotes

Footnote 1

"Consultation statement" as required by subsection 28(2) of the Pest Control Products Act.

Return to footnote 1 referrer

Footnote 2

"Decision statement" as required by subsection 28(5) of the Pest Control Products Act.

Return to footnote 2 referrer

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