Proposed Maximum Residue Limit PMRL2020-15, Pyroxsulam

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Pest Management Regulatory Agency
29 July 2020
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2020-15E-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 a new use on triticale to the product label of Simplicity GoDRI Herbicide, containing technical grade pyroxsulam, is acceptable. The specific use approved in Canada is detailed on the label of Simplicity GoDRI Herbicide, Pest Control Products Act Registration Number 31916.

The evaluation of this pyroxsulam application indicated that the end-use product has value and the human health and environmental risks associated with the new use 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 MRLs for pyroxsulam 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.

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 MRLs, to be added to the MRLs already established for pyroxsulam, are as follows.

Table 1 Proposed maximum residue limits for pyroxsulam
Common name Residue definition MRL (ppm) Footnote 1 Food commodity
Pyroxsulam N-(5,7-dimethoxy[1,2,4]triazolo[1,5-a]pyrimidin-2-yl)-2-methoxy-4-(trifluoromethyl)-3-pyridinesulfonamide 0.01 Eggs, fat, meat and meat byproducts of cattle, goats, hogs, horses, poultry and sheep; milk, triticale
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

MRLs may vary from one country to another for a number of reasons, including differences in pesticide use patterns and the locations of the crop field trials used to generate residue chemistry data. For livestock commodities, differences in MRLs can also be due to different livestock feed items and practices.

Table 2 compares the MRLs proposed for pyroxsulam in Canada with the corresponding American tolerances and Codex MRLFootnote 1. American tolerances are listed inthe Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. A listing of established Codex MRLs is available on the Codex Alimentarius Pesticide Index webpage, by pesticide or commodity.

Table 2 Comparison of Canadian MRLs, American Tolerances and Codex MRLs (where different)
Food commodity Canadian MRL (ppm) American Tolerance (ppm) Codex MRL (ppm)
Triticale 0.01 0.01Footnote 1 Not established
Eggs, fat, meat and meat byproducts of cattle, goats, hogs, horses, poultry and sheep, milk 0.01 Not established
Footnote 1

Triticale tolerance is covered under that of wheat, in accordance with 40 CFR180.1

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Next steps

The PMRA invites the public to submit written comments on the proposed MRLs for pyroxsulam 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 MRLs. Comments received will be addressed in a separate document linked to this PMRL. The established MRLs will be legally in effect as of the date that they are 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 on wheat were reassessed in the framework of this petition. The dietary exposure assessment on file is considered adequate to cover the residues of pyroxsulam expected from the new use of this product. No health risks of concern have been identified for any segment of the population including infants, children, adults and seniors.

Maximum residue limit

The recommendation for the maximum residue limit (MRL) for pyroxsulam on triticale was based upon previous 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 triticale.

Table A1 Summary of field trial and processing data used to support the MRL
Commodity Application method/ Total application rate (g a.i./ha)Footnote 1 Preharvest interval (days) Lowest average field trial residues (ppm) Highest average field trial residues (ppm) Experimental processing factor
Wheat grain Foliar broadcast/14.3–15.6 50–110 <0.01 <0.01 No quantifiable residues observed at exaggerated rates
Footnote 1

g a.i./ha = grams of active ingredient per hectare

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Based on the dietary burden and livestock metabolism studies, an MRL of 0.01 ppm for eggs, fat, meat and meat by-products of cattle, goats, hogs, horses, poultry and sheep to cover residues of pyroxsulam is also proposed.

Following the review of all available data, the MRLs as proposed in Table 1 are recommended to cover residues of pyroxsulam. Residues in the crop and livestock commodities at the proposed MRLs 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.

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