Proposed Maximum Residue Limit PMRL2021-29, Bromoxynil

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Pest Management Regulatory Agency
22 July 2021
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2021-29E-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 IPCO Logic M Liquid Herbicide, containing technical grade bromoxynil and MCPA, is acceptable. The specific uses approved in Canada are detailed on the label of IPCO Logic M Liquid Herbicide, Pest Control Products Act Registration Number 28109.

The evaluation of this bromoxynil and MCPA 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 bromoxynil is being conducted via this document (see Next steps). A summary of the field trial data used to support the proposed MRL can be found in Appendix I. The currently established MRLs of 0.04 ppm for MCPA in/on annual canarygrass bran and 0.03 ppm for MCPA in/on annual canarygrass seeds are sufficient to cover residues resulting from this new use and are therefore unaffected by this MRL action.

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 bromoxynil, is as follows.

Table 1 Proposed maximum residue limit for bromoxynil
Common name Residue definition MRL
(ppm)Table 1 Footnote 1
Food commodity
Bromoxynil 3,5-dibromo-4-hydroxybenzonitrile 0.05 Annual canarygrass seeds

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 is no American tolerance for bromoxynil in or on the petitioned commodity listed in the Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide, nor are there Codex MRLsFootnote 1 listed for bromoxynil in or on any commodity on the Codex Alimentarius Pesticide Index webpage.

Next steps

The PMRA invites the public to submit written comments on the proposed MRL for bromoxynil 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 in/on wheat and barley were reassessed in the framework of this petition. In addition, the results of processing studies in treated wheat and barley were considered to determine the potential for concentration of residues of bromoxynil into processed commodities.

Maximum residue limit

The recommendation for the maximum residue limit (MRL) for bromoxynil was based upon the previously reviewed 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 method/Total application rate
(kg a.i./ha)Table A1 Footnote 1
Preharvest interval
Lowest average field trial residues
Highest average field trial residues
Experimental processing factor
Wheat grain Foliar/0.28–1.12 0–155 <0.01 0.05 No concentration in processed fractions
Barley grain Foliar/0.28–0.56 29–101 <0.02 <0.05 No concentration in processed fractions

Following the review of all available data, the MRL as proposed in Table 1 is recommended to cover residues of bromoxynil. Residues of bromoxynil 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.

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