Pest Management Regulatory Agency
23 June 2011
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2011-19E-PDF (PDF version)

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Under the authority of the  Pest Control Products Act, Health Canada's Pest Management Regulatory Agency (PMRA) has re-evaluated the human health and environmental risk as well as the value of tralkoxydim and is proposing continued registration of products containing tralkoxydim for sale and use in Canada.

Tralkoxydim is a herbicide used in Canada to control annual grass weeds on barley, rye, triticale and wheat. Tralkoxydim is also applied to selected forage grasses that are used for seeding only.

The evaluation of available scientific information for tralkoxydimapplications indicated that the end-use products have merit and value in the food and crop industry and do not present unacceptable risks to human health or the environment. Details regarding the re-evaluation can be found in Proposed Re-evaluation Decision PRVD2009-08, Tralkoxydim, published 26 June 2009.

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. In the absence of a specified MRL, the 0.1 ppm general MRL applies in accordance with Section B.15.002(1)(a) of the Canadian  Food and Drug Regulations.

The re-evaluation of the Canadian field trial data supporting the registration of tralkoxydim indicated that the Agency has sufficient residue data on file for the cereal-grain crop group representative commodities of barley and wheat which can be extended to rye and triticale, given the same use pattern. Supporting residue data are provided in Appendix 6, Section 1.3.2 of PRVD2009-08.

Consultation on the proposed MRLs for tralkoxydim is being conducted via this document (see Next Steps).

To comply with Canada's international trade obligations, consultation on the proposed MRLs is also being conducted internationally by notifying the  World Trade Organization, as coordinated by the  Standards Council of Canada.

The proposed MRLs for tralkoxydim in Canada in or on food are as follows.

Table 1 - Proposed Maximum Residue Limits for Tralkoxydim

Common Name	Residue Definition	MRL (ppm)	Food Commodity
Tralkoxydim	2-[1-(ethoxyimino)propyl]-3-hydroxy-5-mesitylcyclohex-2-enone	0.02	Rye, triticale

A complete list of all pesticide MRLs established in Canada can be found on the Maximum Residue Limits for Pesticides webpage in the Pesticides and Pest Management section of Health Canada's website.

International Situation and Trade Implications

Table 2 compares the MRLs proposed for tralkoxydim in Canada with corresponding American tolerances and Codex Alimentarius MRLs.^{Footnote 1} American tolerances are listed in the  Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. Currently, Codex MRLs have not been established for tralkoxydim on any commodity. A listing of all established Codex MRLs is available on the Codex Alimentarius  Pesticide Residues in Food website.

Table 2 - Comparison of Canadian MRLs, American Tolerances and Codex MRLs

Food Commodity	Canadian MRL (ppm)	American Tolerance (ppm)	Codex MRL (ppm)
covered by the tolerance for wheat in accordance with the definitions found under 40 CFR Part 180.1.
Rye	0.02	Not established	Not established
Triticale	0.02	0.02	Not established

Next Steps

The PMRA invites the public to submit written comments on the proposed MRLs for tralkoxydim 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 for tralkoxydim and posting a corresponding Established Maximum Residue Limit document in the Pesticides and Pest Management section of Health Canada's website.