Proposed Maximum Residue Limit PMRL2023-37, Rimsulfuron

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Pest Management Regulatory Agency
13 July 2023
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2023-37E-PDF (PDF version)

Purpose of consultation

A maximum residue limit (MRL)^{Footnote 1} is being proposed for the pesticide rimsulfuron, as part of the following application for Canadian use, under submission number 2022-0354.

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 commodity of cranberries to the product label of Prism SG Herbicide containing technical grade rimsulfuron, to control labelled weeds. The specific uses approved in Canada are detailed on this product label, Pest Control Products Act Registration Number 30057.

The evaluation of this rimsulfuron 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 foods listed in Table 1 were shown to be acceptable when rimsulfuron is used according to the supported label directions. Therefore, foods containing residues resulting from this use are 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:

Identifying the toxicology hazards posed by the pesticide;
Determining the "acceptable dietary level" for Canadians (including all vulnerable populations), which is protective of adverse health effects;
Estimating human dietary exposure to the pesticide from all applicable sources (domestic and imported commodities); and
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 rimsulfuron is being conducted via this document. Health Canada invites the public to submit written comments on the proposed MRL for rimsulfuron 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 rimsulfuron, is summarized in Table 1.

Table 1 Proposed maximum residue limit for rimsulfuron
Common Name	Residue Definition	MRL (ppm)^{Table 1 Footnote 1}	Food Commodity
Rimsulfuron	N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-3- (ethylsulfonyl)-2-pyridinesulfonamide	0.02	Low growing berries, except strawberries^{Table 1 Footnote 2} (crop subgroup 13-07H; except lowbush blueberries^{Table 1 Footnote 3} and lingonberries^{Table 1 Footnote 4})
Table 1 Footnote 1 ppm = parts per million Return to table 1 footnote 1 referrer Table 1 Footnote 2 As cranberry is the representative commodity of crop subgroup 13-07H, an MRL for the crop subgroup is being recommended. Return to table 1 footnote 2 referrer Table 1 Footnote 3 Lowbush blueberries are excluded from this MRL action as an MRL of 0.05 ppm is already established for this commodity. Return to table 1 footnote 3 referrer Table 1 Footnote 4 Lingonberries are excluded from this MRL action as an MRL of 0.01 ppm is already established for this commodity. Return to table 1 footnote 4 referrer

The commodities included in the listed crop subgroup can be found on the Residue Chemistry Crop Groups webpage in the Pesticides section of Canada.ca.

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 geographic locations of the crop field trials used to generate residue chemistry data.

Table 2 compares the MRLs proposed for rimsulfuron in Canada with corresponding American tolerances and Codex MRLs.^{Footnote 2} American tolerances are listed in the Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. Currently, there are no Codex MRLs listed for rimsulfuron in or on any commodity on the Codex Alimentarius Pesticide Index webpage.

Table 2 Comparison of proposed Canadian MRLs, American tolerances and Codex MRLs
Food Commodity	Canadian MRL (ppm)	American Tolerance (ppm)	Codex MRL (ppm)
Low growing berries, except strawberries (crop subgroup 13-07H; except lowbush blueberries and lingonberries)	0.02	0.02 (Berry, low growing, except strawberry, subgroup 13-07H)	Not Established

Next steps

Health Canada invites the public to submit written comments on the proposed MRL for rimsulfuron 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 rimsulfuron were submitted to support the use of Prism SG Herbicide on cranberries.

Dietary risk assessment results

Studies in laboratory animals showed no acute health effects. Consequently, a single dose of rimsulfuron 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 6% of the acceptable daily intake, and therefore there are no health concerns.

Maximum residue limit

The recommendation for the maximum residue limit (MRL) for rimsulfuron 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 low growing berries, except strawberries (crop subgroup 13-07H, except lowbush blueberries and lingonberries).

Table A1 Summary of field trial data used to support the MRL
Commodity	Application method/Total application rate (g a.i./ha)^{Table 3 Footnote 1}	Preharvest interval (days)	Lowest average field trial residues (ppm)	Highest average field trial residues (ppm)
Cranberry Fruit	Foliar/ 69–72	56–59	<0.01	<0.01
Table 3 Footnote 1 g a.i./ha = grams of active ingredient per hectare Return to table 3 footnote 1 referrer

Following the review of all available data, the MRL proposed in Table 1 is recommended, in order to cover residues of rimsulfuron. Dietary risks from exposure to residues of rimsulfuron in these crop commodities at the proposed MRL 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.

References

PMRA No.	Citation
3264871	2014, Rimsulfuron: Magnitude of the Residue on Cranberry, DACO: 7.3,7.4.1

Page details

Date modified:: 2023-09-28

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