Proposed Maximum Residue Limit PMRL2023-22, Mandestrobin

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Pest Management Regulatory Agency
18 April 2023
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2023-22E-PDF (PDF version)

Purpose of consultation

Maximum residue limits (MRLs)Footnote 1 are being proposed for the pesticide mandestrobin, as part of the following application for Canadian use, under submission number 2020-5079.

Under the authority of the Pest Control Products Act, Health Canada's Pest Management Regulatory Agency (PMRA) has accepted the requested application to add the new commodities of head lettuce and leaf lettuce to the product label of Intuity Fungicide containing technical grade mandestrobin, to suppress head rot and leaf drop (Sclerotinia sclerotiorum). The specific uses approved in Canada are detailed on this product label, Pest Control Products Act Registration Number 32288.

The evaluation of this mandestrobin application indicated that the end-use product has value, and the human health and environmental risks associated with the new uses are acceptable. Dietary risks from the consumption of foods listed in Table 1 were shown to be acceptable when mandestrobin is used according to the supported label directions. Therefore, foods containing residues resulting from this use are safe to eat, and MRLs are being proposed as a result of this assessment. A summary of the field trial data used to support the proposed MRLs 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 MRLs for mandestrobin is being conducted via this document. Health Canada invites the public to submit written comments on the proposed MRLs for mandestrobin 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 MRLs is also being conducted internationally by notifying the World Trade Organization, as coordinated by the Canada's Notification Authority and Enquiry Point.

Proposed MRLs

The proposed MRLs, to be added to the MRLs already established for mandestrobin, are summarized in Table 1.

Table 1 Proposed Maximum Residue Limits for Mandestrobin
Common name Residue definition MRL (ppm)Footnote 1 Food commodity
Mandestrobin 2-[(2,5-dimethylphenoxy)methyl]-α-methoxy-
4.0 Leaf lettuce
0.08 Head lettuce
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

The MRLs proposed for mandestrobin in Canada are the same as corresponding American tolerances as listed in the Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. Currently, there are no Codex MRLs Footnote 2 listed for mandestrobin in or on the petitioned commodities on the Codex Alimentarius Pesticide Index webpage.

Next steps

Health Canada invites the public to submit written comments on the proposed MRLs for mandestrobin 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 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 limits

Residue data for mandestrobin were submitted to support the use of Intuity Fungicide on head lettuce and leaf lettuce.

Dietary risk assessment results

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

Chronic dietary (food plus drinking water) intake estimates indicated that the general population and all population subgroups are exposed to less than 10% of the acceptable daily intake, and therefore there are no health concerns.

Maximum residue limits

The recommendation for maximum residue limits (MRLs) for mandestrobin 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 MRLs for head lettuce and leaf lettuce.

Table A1 Summary of field trial data used to support the MRLs
Commodity Application method/ Total application rate
(g a.i./ha) Footnote 1
Preharvest interval (days) Lowest average field trial residues
Highest average field trial residues
Head lettuce Foliar application/ 830-891 18-70 <0.010 0.049
Leaf lettuce Foliar application/ 788-866 9-33 <0.010 2.4
Footnote 1

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

Return to footnote 1 referrer

Following the review of all available data, the MRLs proposed in Table 1 are recommended in order to cover residues of mandestrobin. Dietary risks from exposure to residues of mandestrobin in these crop commodities at the proposed MRLs were shown to be acceptable for the general population and all subpopulations, including infants, children, adults and seniors. Thus, the foods that contain residues as listed in Table 1 are considered safe to eat.

PMRA# Citation
3169309 2020, Mandestrobin (S-2200): Magnitude of the Residue on lettuce (head and leaf), DACO: 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.

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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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