24 February 2010
HC Pub: 100057
ISBN: 978-1-100-14191-6 (print version)
ISBN: 978-1-100-14192-3 (PDF version)
Catalogue number: H113-24/2010-14E (print version)
Catalogue number: H113-24/2010-14E-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 concluded that the addition of new uses on sweet corn to the product label Impact Herbicide, containing technical grade topramezone, is acceptable. The specific uses approved in Canada are detailed on the label of Impact Herbicide, Pest Control Products Act Registration Number 28141.

The evaluation of this topramezone application indicated that the end-use product has merit and value and that the human health and environmental risks associated with the new uses are acceptable. Details regarding the registration can be found in the corresponding Evaluation Report that is available in the Pesticides and Pest Management section of Health Canada's website, under Public Registry, Pesticide Product Information Database.¹

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 topramezone is being conducted via this document (see Next Steps, the last section of this document).

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 Standards Council of Canada.

The proposed MRL for topramezone in Canada in or on food, to be added to those MRLs already legally established, is as follows.

Table 1 Proposed Maximum Residue Limit for Topramezone

Common Name	Residue Definition	MRL (ppm)	Food Commodity
Topramezone	[3-(4,5-dihydro-3-isoxazolyl)-2-methyl-4-(methylsulfonyl)phenyl](5-hydroxy-1-methyl-1H-pyrazol-4-yl)methanone	0.01	Sweet corn kernels plus cob with husks removed

A complete list of all 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

The proposed Canadian MRL for topramezone is the same as the corresponding tolerance established in the United States (tolerances are listed in the  Electronic Code of Federal Regulations by pesticide). Currently, Codex MRLs² have not been established for topramezone on any commodity. A listing of established Codex MRLs is available on the  Pesticide Residues in Food website.

Next Steps

The PMRA invites the public to submit written comments on the proposed MRL for topramezone up to 75 days from the date of publication of this document. Please forward your comments to Publications (see the contact information on the cover page of this document). The PMRA will consider all comments received before making a final decision on the proposed MRL for topramezone and posting a corresponding Established Maximum Residue Limit (EMRL) document in the Pesticides and Pest Management section of Health Canada's website.