Proposed Maximum Residue Limit PMRL2019-33, 2,4-D

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Pest Management Regulatory Agency
26 November 2019
ISSN: 1925-0843
Catalogue number: H113-24/2019-33E-PDF (PDF version)

Under the authority of the Pest Control Products Act, Health Canada’s Pest Management Regulatory Agency (PMRA) has concluded that the addition of new uses on annual canarygrass to the product label of BlackHawk Herbicide containing technical grade pyraflufen-ethyl and 2,4-D, is acceptable. The specific uses approved in Canada are detailed on the label of BlackHawk Herbicide, Pest Control Products Act Registration Number 32111.

The evaluation of this 2,4-D application indicated that the end-use product has value and the human health and environmental risks associated with the new uses are acceptable.

Before registering a pesticide for food use in Canada, the PMRA must determine the quantity of residues that are likely to remain in or on the food when the pesticide is used according to label directions and that such residues will not be a concern to human health. This quantity is then legally established as a maximum residue limit (MRL). An MRL applies to the identified raw agricultural food commodity as well as to any processed food product that contains it, except where separate MRLs are specified for the raw agricultural commodity and a processed product made from it.

Consultation on the proposed MRL for 2,4-D is being conducted via this document (see Next Steps). MRL consultation for the other active ingredient, pyraflufen-ethyl, present in BlackHawk Herbicide is being conducted under a separate action.

A summary of the field trial data used to support the proposed MRL can be found in Appendix I.

To comply with Canada’s international trade obligations, consultation on the proposed MRL is also being conducted internationally by notifying the World Trade Organization, as coordinated by the Canada’s Notification Authority and Enquiry Point.

The proposed MRL, to be added to the MRLs already established for 2,4-D, is as follows.

Table 1 - Proposed Maximum Residue Limit for 2,4-D
Common Name Residue Definition MRL (ppm)Footnote 1 Food Commodity
2,4-D (2,4-dichlorophenoxy)acetic acid 0.01 Annual canarygrass seeds
Footnote 1

ppm = parts per million

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MRLs established in Canada may be found using the Maximum Residue Limit Database on the Maximum Residue Limits for Pesticides webpage. The database allows users to search for established MRLs, regulated under the Pest Control Products Act, both for pesticides or for food commodities.

International Situation and Trade Implications

Currently, there are no American tolerances for 2,4-D for annual canarygrass seeds listed in the Electronic Code of Federal Regulations, 40 CFR, part 180, by pesticide, nor are there Codex MRLsFootnote 1 listed for 2,4-D for the petitioned commodity on the Codex Alimentarius Pesticide Index webpage.

Next Steps

The PMRA invites the public to submit written comments on the proposed MRL for 2,4-D up to 75 days from the date of publication of this document. Please forward your comments to Publications. The PMRA will consider all comments received before making a final decision on the proposed MRL. Comments received will be addressed in a separate document linked to this PMRL. The established MRL will be legally in effect as of the date that it is entered into the Maximum Residue Limit Database.

Appendix I

Summary of Field Trial Data Used to Support the Proposed Maximum Residue Limit

Previously reviewed residue data from field trials conducted with wheat and barley were reassessed in the framework of this petition. In addition, a processing study in treated wheat was also reassessed to determine the potential for concentration of residues of 2,4-D into processed commodities.

Maximum Residue Limit

The recommendation for the maximum residue limit (MRL) for 2,4-D was based upon the field trial data, and the guidance provided in the OECD MRL Calculator. Table A1 summarizes the residue data used to calculate the proposed MRL for annual canarygrass seeds.

Table A1 - Summary of Field Trial and Processing Data Used to Support the MRL
Commodity Application
(g a.e./ha)Footnote 1
Field Trial
Residues (ppm)
Field Trial
Residues (ppm)
Wheat Grain Postemergent Foliar/
58–109 <0.01 <0.01 No quantifiable residues observed at exaggerated rates
Wheat Grain Postemergent Foliar/
58–109 <0.01 <0.01
Barley Grain Postemergent Foliar/
56–79 <0.01 <0.01 No quantifiable residues observed at exaggerated ratesFootnote 2
Footnote 1

g a.e./ha = grams of active equivalents per hectare

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Processing data extended from wheat

Return to footnote 2 referrer

Following the review of all available data, the MRL as proposed in Table 1 is recommended to cover residues of 2,4-D. Residues of 2,4-D in this crop commodity at the proposed MRL will not pose an unacceptable risk to any segment of the population, including infants, children, adults and seniors.


Footnote 1

The Codex Alimentarius Commission is an international organization under the auspices of the United Nations that develops international food standards, including MRLs.

Return to footnote 1 referrer

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