Proposed Maximum Residue Limit PMRL2023-01, Sodium Acifluorfen

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Pest Management Regulatory Agency
19 January 2023
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2023-1E-PDF (PDF version)

Purpose of consultation

A maximum residue limit (MRL)Footnote 1 is being proposed for the pesticide sodium acifluorfen, as part of the following application for Canadian use, under submission number 2017-5160.

Under the authority of the Pest Control Products Act, Health Canada's Pest Management Regulatory Agency (PMRA) is proposing acceptability of the requested application to add the new commodity of carrots to the product label of Ultra Blazer Herbicide containing technical grade sodium acifluorfen, for the suppression of redroot pigweed. The specific use approved in Canada is detailed on this product label, Pest Control Products Act Registration Number 32330.

The evaluation of this sodium acifluorfen application indicated that the end-use product has value, and the human health and environmental risks associated with the new use are acceptable. Dietary risks from the consumption of food listed in Table 1 were shown to be acceptable when sodium acifluorfen is used according to the supported label directions. Therefore, food containing residues resulting from this use is safe to eat, and an MRL is being proposed as a result of this assessment. A summary of the field trial data used to support the proposed MRL can be found in Appendix I.

Dietary health assessment

In assessing the risk of a pesticide, Health Canada combines information on pesticide toxicity with information on the degree and duration of dietary exposure to the pesticide residue from food. The risk assessment process involves four distinct steps:

  1. Identifying the toxicology hazards posed by the pesticide;
  2. Determining the "acceptable dietary level" for Canadians (including all vulnerable populations), which is protective of adverse health effects;
  3. Estimating human dietary exposure to the pesticide from all applicable sources (domestic and imported commodities); and
  4. Characterizing health risk by comparing the estimated human dietary exposure to the acceptable dietary level.

Before registering a pesticide for food use in Canada, Health Canada must determine the quantity of residues that could 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 (Steps 3 and 4 above). If estimated human exposure is less than or equal to the acceptable level (developed in Step 2 above), Health Canada concludes that consuming residues resulting from use according to approved label directions is not a health concern. The proposed MRL is then subject to consultation to legally specify it as an MRL.

An MRL applies to the identified raw agricultural food commodity as well as to any processed food product that contains it, except for certain instances where different MRLs are specified for the raw agricultural commodity and its processed product(s).

Consultation on the proposed MRL for sodium acifluorfen is being conducted via this document. Health Canada invites the public to submit written comments on the proposed MRL for sodium acifluorfen in accordance with the process outlined in the Next steps 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 Canada's Notification Authority and Enquiry Point.

Proposed MRL

The proposed MRL, to be added to the MRLs already established for sodium acifluorfen, is summarized in Table 1.

Table 1 Proposed Maximum Residue Limit for sodium acifluorfen
Common name Residue definition MRL (ppm)Table 1 Footnote 1 Food commodity
Sodium acifluorfen sodium 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2- nitrobenzoate, including the metabolites consisting of the corresponding acid, methyl ester and amino analogues 0.06 Carrot roots
Table 1 - Footnote 1

ppm = parts per million

Return to Table 1 Footnote 1 referrer

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 sodium acifluorfen 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 2 listed for sodium acifluorfen in or on any commodity on the Codex Alimentarius Pesticide Index webpage.

Next steps

Health Canada invites the public to submit written comments on the proposed MRL for sodium acifluorfen up to 75 days from the date of publication of this document. Please forward your comments to Publications. Health Canada will consider all comments received and a science-based approach will be applied in 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

Residue data for sodium acifluorfen were submitted to support the use of Ultra Blazer Herbicide on carrots.

Dietary risk assessment results

Studies in laboratory animals showed no acute health effects. Consequently, a single dose of sodium acifluorfen is not likely to cause acute health effects in the general population (including infants and children).

Chronic dietary (food only) intake estimates indicated that the general population and all population subgroups are exposed to less than 2% of the acceptable daily intake, and therefore there are no health concerns.

Maximum residue limit

The recommendation for a maximum residue limit (MRL) for sodium acifluorfen was based upon the submitted 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 carrot roots.

Table A1 Summary of field trial data used to support the MRL
Commodity Application method/Total application rate
(g a.i./ha)Table A1 Footnote 1
Preharvest interval
Lowest average field trial residues
Highest average field trial residues
Carrot roots Foliar/22.0–23.2 41–43 <0.06 <0.06
Table A1 - Footnote 1

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

Return to Table A1 Footnote 1 referrer

Following the review of all available data, the MRL proposed in Table 1 is recommended to cover residues of sodium acifluorfen. Dietary risks from exposure to residues of sodium acifluorfen in this crop commodity at the proposed MRL were shown to be acceptable for the general population and all subpopulations, including infants, children, adults and seniors. Thus the food that contains residues as listed in Table 1 is considered safe to eat.


PMRA# Citation
2803052 2017, Residue report - Acifluorfen: Magnitude of the Residue on Carrots, DACO: 7.2,7.3,7.4.1,7.4.2


Footnote 1

A maximum residue limit (MRL) is the maximum amount of residue that may remain in or on food when a pesticide is used according to label directions.

Return to footnote 1 referrer

Footnote 2

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 2 referrer

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