Towards a national-scale water monitoring program for pesticides — What we heard

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Organization: Health Canada

Date published: August 2023

Executive summary

The Government of Canada is committed to ensuring that Health Canada's Pest Management Regulatory Agency (PMRA) makes timely, science-based decisions to support the safe and sustainable use of effective pesticide products in Canada with the support of Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC). Since August 2021, the PMRA has been undergoing a transformation process that will strengthen its oversight and protection of human health and the environment and enhance transparency. Improving the availability of real-world water monitoring data to further support pesticide regulatory decisions and enhancing the transparency of decision-making will contribute to addressing those objectives.

Developing a water monitoring framework will provide guidance to pesticide water monitoring programs as well as guide the design and implementation of a national-scale water monitoring program for pesticides (NWMPP). A NWMPP will aim to generate data for a broad suite of pesticides from a national network of sites, resulting in increased availability and use of real-world data to strengthen pesticide regulatory decisions for the protection of human health and the environment. Development of the framework is being informed by feedback received from a federal, provincial, territorial survey, and from technical working group meetings with federal, provincial, and territorial governments, academia, grower groups, non-governmental organizations, and pesticide manufacturers.

A survey completed with federal, provincial, and territorial partners provided important feedback on the current landscape for water monitoring programs across Canada. In general, pesticide monitoring programs in Canada vary greatly in terms of objectives and purposes, number of sites, frequency of sampling, priority pesticides, data sharing and reporting. Survey results highlighted a lack of funding and resources for water monitoring programs for pesticides, the need for network expansion for better geographical coverage, and the need for reduced duplication among, and greater complementarity across, programs. Overall, respondents were eager to collaborate with the PMRA on the development of a national-scale program.

During technical working group meetings, during the spring and summer of 2022, several topics related to water monitoring were explored. The following are high-level points from these discussions:

Water monitoring goals

Participants confirmed the importance of real-world water monitoring data for use in regulatory decisions. They indicated support for the following water monitoring goals outlined by the PMRA:

Other goals were suggested including consideration of the effects of pesticide mixtures in aquatic environments.

Site selection

Participants clearly indicated that criteria for site selection must be clear and science-based. It was recommended that selected sites be representative of different watershed scales, landscapes and use areas, while indicating that final site selection can be influenced by the availability of ancillary data (e.g., temperature, water flow, crop information, pesticide use in the area). Selecting sites that are complementary or co-located with provincial and territorial sites was highly recommended as well as working closely with growers and partners for access to private land.

Sampling frequency and timing

Participants agreed that a higher sampling frequency would result in a higher value dataset but cautioned that this would require more funding and resources. We heard that the timing and frequency of sampling can be region-specific and that local grower practices should be considered. A combination of event-based (e.g., rain) and scheduled sampling was identified as a valuable consideration.

Sampling methods

Participants indicated that sampling methods should align with program goals and be adaptable to regional differences. Several sampling methods were discussed, including grab sampling, auto-samplers and passive sampling, and it was suggested that a combination of sampling methods would cover different science-based considerations. Participants highlighted that consistent national sampling protocols would be beneficial in terms of reproducibility and repeatability.

Ancillary data

There was general agreement on the need for ancillary data as it can provide insights when analyzing, interpreting, and reporting results. It was noted by participants that the type of ancillary data will be specific to the different regions of Canada. Participants highlighted that grower participation in a sampling program would assist in the collection of ancillary data, such as crop land area, crop rotation, pesticide application and local-use of equipment and practices.

Priority pesticides and transformation products

Participants supported the PMRA's pesticide prioritization process based on PMRA's priority ranking, which considers environmental fate (persistence and mobility), environmental toxicity, and extent of use (based on sales data). Participants shared some suggestions to strengthen the process. It was recognized that PMRA's current water monitoring pilot program, being conducted in collaboration with ECCC and AAFC, will provide insights into which pesticides may require additional focus in monitoring programs. We heard that initial use of non-target analytical methods could help screen for the presence of pesticides and transformation products, thus allowing resources to be focused on targeted pesticide analytical methods.

Laboratory analysis and analytical methods

There was a common concern around the comparability of data from different laboratories. Much of this discussion focussed on different analytical limits and consistency of internal laboratory methods. We heard that striving to obtain very low detection limits would add several sample manipulations to the analytical method. Adding these steps could increase uncertainty in the data generated. Additionally, aiming for low detection limits would require higher volumes of samples as well as increased time for analysis and costs.

Aquatic Life Reference Values (ALRVs) and Human Health Reference Values (HHRVs)

These reference values were used to guide analytical limits for method development to ensure the data collected will be useful for pesticide risk assessments. Participants expressed concern about using different references values as this could result in contradictory messages to the public (e.g., reporting different exceedance rates at a given site). Other federal and provincial departments may also develop their own thresholds. These are developed with different risk management goals in mind using varying methods. As a result, these thresholds may not be equivalent to PMRA's reference values.

Data access and analysis

Participants expressed support for open data that is flexible, including raw and contextualized data. It was recommended that the data be interactive so that individuals can understand the data. Concerns were raised around privacy for landowners, consistency in data interpretation, avoiding report duplication and the possibility of contradictory messages from different levels of government.

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