A study into the presence of neonicotinoids in Canadian waterways suggests a ban or restriction of neonicotinoid seed treatments is not necessary.
The Environmental Monitoring Working Group (EMWG) was set up to monitor the presence of imidacloprid, clothianidin and thiamethoxam in waterways after Health Canada’s Pest Management Regulatory Agency (PMRA) 2016 decision to phase out imidacloprid in three to five years.
The PMRA cited acute and chronic risks to aquatic invertebrates as reasons for the ban, and its final decision on whether to ban imidacloprid is expected in December.
The PMRA is also reviewing and may ban two other neonicotinoids, thiamethoxam and clothianidin, because of their effects on aquatic insects. The final decisions on these neonicotinoids are expected to be made in 2020.
Environment Canada doesn’t routinely test ponds, wetlands and creeks across the Prairies for pesticides and little data is available on the levels of neonicotinoids in prairie water, or if the neonicotinoids affect invertebrates in the region.
In the absence of such data, the EMWG established protocols for sampling, storage, handling and shipping, sample preparation, analytical methods for the tests, as well as detection limits for the three neonicotinoids.
The EMWG co-ordinated with provincial and federal water monitoring agencies, and flowing water from all major watersheds in Canada were tested. Ducks Unlimited Canada (DUC) helped conduct wetland monitoring.
In the prairie provinces, 620 samples at 168 sites were collected in 2017 from flowing water systems including streams, rivers and irrigation canals. A further 60 wetland sites were monitored by DUC.
The samples were taken throughout the growing season.
“Detection frequency and concentration of imidacloprid, clothianidin and thiamethoxam were low, with majority being below the limits of detection. When detected, the insecticides were typically well below the chronic or acute endpoints established by PMRA for imidacloprid. By the middle or end of July, the insecticides were no longer detectable, said Warren Ward of the Canola Council of Canada during the University of Saskatchewan’s Soils and Crops event in Saskatoon.
He said in instances when neonicotinoid insecticides were found to be above acute or chronic levels, greenhouse or urban applications could be to blame not field crop use, but further investigation is needed.
“The data does not support any kind of restriction or ban on neonicotinoid seed treatment use, especially for field crops such as canola, pulses, cereals,” Ward said.
Soon after the PMRA 2016 decision to ban imidacloprid, farmers and industry stakeholders said restricted use of the neonicotinoid would cost the industry hundreds of millions of dollars.
In response to the PMRA decision, Agriculture Canada established a multi-stakeholder forum on neonicotinoids, which lead to the development to the EMWG.
Until last fall, the PMRA accepted submissions of new information that could influence its final decision on whether it will ban the use of imidacloprid.
Water testing results from the EMWG’s work last summer have been submitted to the PMRA for consideration.
“In January 2017, the PMRA provided the EMWG with parameters that needed to be addressed in order to generate scientifically robust environment water monitoring data. The generation of this data was quickly identified as the main focus area of the EMWG,” Ward said.
Provincial and Canadian grower associations provided most of the funding for the EMWG.