Summary of SAC-PCP’s recommendations on the second charge question

This page describes a summary of the Committee's recommendations on the second charge question (scientific communication of maximum residue limits) and the PMRA's response.

Context

One of the objectives of the second SAC-PCP meeting, which occurred virtually over Zoom on October 20, 2022, was to present the Committee members with their second official charge question for advice relating to the scientific communication surrounding Maximum Residue Limits.

Meeting summary

The meeting summary from the second SAC-PCP meeting can be found here: Science Advisory Committee on Pest Control Products: Meeting summary October 20, 2022 - Canada.ca.

Charge question

The purpose of the presentation on the charge question as it relates to the scientific communication of Maximum Residue Limits was to:

Introduce the concept of a Maximum Residue Limit (MRL) and explain the scientific process of how it is determined;
Introduce the proposed maximum residue limit (PMRL) consultation document used to propose a Canadian MRL for pesticides;
Seek approaches to clearly reflect the science and how to enhance the public's understanding of MRLs; and,
Seek input on the science aspects of MRL setting, particularly on the charge question below.

The second official charge question was presented as follows:

"What additional science information or explanation would be helpful to include in the PMRL draft consultation document to enable better stakeholder understanding of the scientific approach that is used to establish new or revised maximum residue limits (MRLs)?"

Summary of SAC-PCP's recommendations and the PMRA's response

Define maximum residue limits as "predicted residue concentrations" when communicating with the public (not a unanimous recommendation from SAC).

PMRA's response:

The SAC-PCP recommendation was considered. The term maximum residue limit (MRL) is an internationally recognised term, as such Canada cannot change the term unilaterally or modify the definition as this is likely to create more confusion rather than adding further clarity.

"MRL" is also a widely used term for online searches, therefore this identifiable and familiar term must be retained. Additional text has been included in the Introduction of the PMRL consultation document to add more clarity around the purpose of MRLs and on MRLs in general.

Furthermore, multiple sources have indicated that confusion surrounding MRLs could be reduced by developing and improving communications on what MRLs are and their purpose, and to tailor these communications to a variety of audiences. Accordingly, rather than incorporating the proposed alternative or additional terminology, a more global approach to public communication of the science and regulatory context on MRLs is being developed.
Revise the PMRL introduction to include information about the pesticide, relevant values from the risk assessments, and maximum safety limits (to link the maximum residue limit with toxicity levels).

PMRA's response:

PMRA agrees that adding more information on the pesticide and toxicology aspects are helpful additions, and a risk comparison table has also been included in the PMRL consultation document for proposed MRL amendments.

On the inclusion of a 'maximum safety limit' for each food commodity, the dietary risk assessment process used by the PMRA considers all commodities possibly treated with a given pesticide. This process accounts for the total possible exposure to that pesticide from the whole diet of an individual and is reflective of how people eat a variety of foods in Canada. Determining a "maximum safety limit" for each commodity would not be practical nor static, given that an amendment to one use for a given commodity can shift both the relative and overall residue contribution from each crop to the risk profile of the pesticide. In line with international best practices, PMRA assesses the overall risk to the pesticide and not just the risk associated with each individual commodity.
Add a preamble to explain why the government allows the use of pesticides, what the government is doing to reduce pesticide use, why residues may remain on food, and how PMRA ensures the residues are safe for humans and the environment.

PMRA's response:

PMRA agrees with the recommendation and a new introductory section (section 1.0) has been added in the PMRL consultation document. Section 1.0 Pesticides in Canada now includes a preamble on why pesticides are important to Canadian growers. The following context has also been added:

"All pesticides, for both organic and conventionally grown crops that are approved for use in Canada are regulated by Health Canada's Pest Management Regulatory Agency (PMRA). The PMRA reviews all new pesticide applications and also re-evaluates existing products on a regular basis. Pesticides provide both organic and conventional growers in Canada with a variety of options to help minimize damage to their crops and livestock from pests, helping to ensure high quality yields of food products are available to Canadian consumers."

In addition, Sections 1, 3 and 4 of the PMRL consultation document more clearly outline the information assessed when registering a pesticide, the steps in conducting the assessment and the data considered for the specific MRL(s) that are the focus of the consultation.

Other aspects of the recommendation, such as how the government is working to reduce pesticide use, will be included in more general communications material on the website.
Include meaningful link to the OECD MRL Calculator or do not include.

PMRA's response:

PMRA agrees with the recommendation and explanatory user guide and background information links have been added in the PMRL consultation document.

PMRA has updated the link in the PMRL consultation document to direct people to the OECD MRL Calculator user guide and to the background information on the OECD MRL calculator, rather than the Excel spreadsheet. This information explains that it requires the user to input data as well as the type of data.
Clarify Experimental Processing Factors - how units relate to ppm, and public/scientific perception of maximum residue limits for processed products and calculation of potential Daily intake (PDI).

PMRA's response:

PMRA agrees with the recommendation and additional explanation is provided on processing factors, including how these are calculated. To clarify, processing factors have no units as they are multiplication factors. When the processing factor is less than 1, it means that pesticide residues do not concentrate upon processing, and as such, do not require a separate MRL to be established on the processed food. When no separate MRL is established for a processed food, such as molasses, it means that pesticide residues in molasses are covered by the MRL for the unprocessed commodity, known as the raw agricultural commodity (RAC), which, in the example provided to SAC, is sugar beet roots.

Calculations of expected residues in processed foods using the experimental processing factors have been included in the PMRL consultation document. A footnote to specify if separate MRLs for processed foods are required or not was also added.

Additional information related to the dietary risk assessment has been included in the PMRL consultation document. The change in the risk profile based on the proposed MRLs is now provided to reflect the risk assessment, with and without the inclusion of the new treated import commodity. A footnote was also added to specify which processed foods associated with the RAC, for which an increase MRL is proposed, were included in the dietary risk assessment.
Direct PMRL readers to the PMRA infographic to help explain experimental processing factors, for example, and Direct readers to a flow chart of the HRA/ERA process.

PMRA's response:

PMRA agrees. A link with explanatory text is already included in the existing PMRL consultation document to direct readers to the framework for risk assessment, which includes a high-level flow chart as well as details on how health and environmental risk assessments are conducted:

For more information on how the PMRA assesses and manages risk from pesticides, refer to this guidance document: PMRA Guidance Document, A framework for risk assessment and risk management of pest control products.

For additional information on processing factors, refer to these guidelines and guidance documents:
- Chapter 14 of the Updated Residue Chemistry Guidelines.
- OECD (2008). Test Guideline No. 508: Magnitude of the Pesticide Residues in Processed Commodities, OECD Guidelines for the Testing of Chemicals, Section 5, OECD Publishing, Paris.
  https://doi.org/10.1787/9789264067622-en.
- OECD (2008). Guidance Document on Magnitude of Pesticide Residues in Processed Commodities, Series on Testing & Assessment No. 96, OECD Environment, Health and Safety Publications, OECD Publishing, Paris.
  https://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=env/jm/mono(2008)23&doclanguage=en
Emphasize the robustness of scientific risk assessments.

PMRA's response:

PMRA agrees with the recommendation and has included a new introductory section (Section 1.0) in the PMRL consultation document. Section 1.0 of the PMRL consultation document includes an explanation of the steps of dietary risk assessment currently outlined in Section 3, to further emphasize the robustness of the scientific process required for pesticide risk assessment and in proposing an MRL.
Include real values in a table for the risk assessment, distribution curve for exposures and confidence bounds.

PMRA's response:

PMRA agrees with including the estimated potential exposures to each subpopulation, which are now presented in the PMRL consultation document. The change in the level of risk based on the proposed MRLs is now provided for each subpopulation, with and without the inclusion of the new treated import commodity.
Include exposure data in the form of an intake example.

PMRA's response:

PMRA agrees with the recommendation. Separate, complementary science communication pieces are being developed to address this recommendation. These include an infographic, which represents abstract exposure data in real-world examples. The recommendation to use real-world examples will be applied to future external communication products as well.
Show more uncertainties in the data (avoid perception of overconfidence) and acknowledge potential toxicity of pesticides.

PMRA's response:

PMRA agrees with the recommendation and additional information has been included in the PMRL consultation document, such as additional information on toxicity (e.g., NOAELS, Reference values).
Define, in simple terms, the point of departure (NOEL, NOAEL, LOEL, LOAEL*, etc.) in the risk assessment section, what it was based on (both effect and subject), and what safety factors were applied in the development of the ADI.

PMRA's response:

PMRA agrees with the recommendation and additional information has been included in the PMRL consultation document.

Information related to the "Summary of Toxicology Information for Use in Dietary Exposure Assessment" is now included in the PMRL consultation document. A table presents the toxicology reference values (TRV), including the NOAEL, LOAEL, study, uncertainty factors and the formula used to derive the TRV.

* NOEL: No Observed Effect Level

NOAEL: No Observed Adverse Effect Level

LOEL: Lowest Observed Effect Level

LOAEL: Lowest Observed Adverse Effect Level
Clarify whether environmental risk assessments are also assessed and take note of the environmental risks in the PMRL document (flow chart of HHA/ERA).

PMRA's response:

PMRA agrees with the recommendation and a sentence has been added in Section 1.0 of the PMRL consultation document to indicate that environmental risks are considered for all Canadian pesticide registrations. To clarify, before a pesticide can be registered for use, or a use can be amended in Canada, rigorous scientific evaluations are conducted to make sure risks are acceptable to the health of Canadians and the environment from the use of pesticides. The value of the pesticide must also be demonstrated. For each pesticide, human health and environmental risk assessments are conducted in consideration of how it is to be used. The environmental risk assessment does not directly impact the determination of an MRL, therefore, outcomes of the environmental risk assessment are not included in the PMRL consultation document.

Under section 10(3) of the PCPA, only the health risks must be evaluated when specifying an MRL for a pesticide or use not registered in Canada, for import purposes: "10(3) When specifying maximum residue limits for a pest control product or its components or derivatives pursuant to subsection (1), the Minister shall evaluate only the health risks of the product or its components or derivatives."
Clarify that the Canadian pesticide use label would not change when an import maximum residue limit changes.

PMRA's response:

The recommended text is currently in Section 2.0 of the PMRL consultation document and has been reformatted for greater visibility:

"This increased MRL will not change the registered label, how the pesticide is used in Canada or increase the amount of pesticide residues in the food grown in Canada."

To clarify, an increase in MRL on imported commodities does not affect the way the Canadian registered products are used within Canada, as the use directions and conditions of use have not changed on the Canadian label. If an MRL increases as the result of an import MRL, it has no bearing on how a Canadian grower uses the Canadian registered pesticide on their crops, as the use directions and conditions of use indicated on the registered label must be adhered to at all times. This is a legal requirement.
Provide a public dashboard to show past and current exposures, PDI, and safe exposure limits to visually display the margin of safety, to show that exposures are low.

PMRA's response:

The SAC-PCP recommendation was considered. PMRA agrees that such a dashboard would be useful, however, a visual dashboard requires longer term development and will be considered for inclusion in relevant PMRL consultation documents in the future.

As noted in response 2, additional information related to the dietary risk assessment has been included in the PMRL consultation document. The change in the risk profile based on the proposed MRLs is now provided in a table to reflect the risk assessment, with and without the inclusion of the new treated import commodity.
Summarize previous maximum residue limit calculations for other registered uses to show why the value is higher for the proposed maximum residue limit.

PMRA's response:

PMRA agrees with the recommendation and additional information has been added to the PMRL consultation document.

As noted in responses 2 and 14, additional information related to the dietary risk assessment has been included in the PMRL consultation document. The change in the risk profile based on the proposed MRLs is now provided in a table to reflect the risk assessment, with and without the inclusion of the new treated import commodity.
Reflect comments captured in this report in the infographic PMRA is preparing, to describe the process from risk assessment to maximum residue limit derivation (infographic initiated by PMRA may help reduce the complexity of the messaging).

PMRA's response:

PMRA agrees with the recommendation. As noted in response 9, separate science communication materials are being developed for a variety of audiences, such as an infographic and new web content. These science communication pieces are intended to be standalone pieces not directly tied to any specific consultation.
Communicate the expected change in exposure and margin of safety when proposing MRL changes.

PMRA's response:

PMRA agrees with the recommendation and additional information has been added to the PMRL consultation document. As noted in responses 2, 14 and 15, additional information related to the dietary risk assessment has been included in the PMRL consultation document. The change in the risk profile based on the proposed MRLs is now provided in a table to reflect the risk assessment, with and without the inclusion of the proposed new treated import commodity.

More information

Consistent with Government principles of openness and transparency, SAC-PCP Advisory Reports are available upon request through Pest Management Information Services. For all other inquiries, please reach out to the SAC-PCP Secretariat: pmra.sacpcp-ccspa.arla@hc-sc.gc.ca.

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Date modified:: 2023-06-27

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