Regulations are in place to ensure that glyphosate does not come in direct contact with water. All streams have setback buffers, and permits include weather restrictions on wind to reduce the risk of drift. In designated drinking watersheds there can be no glyphosate applied aerially less than 3.2km upstream from the point of intake. In some watersheds, drinking water is tested before and after application to make sure there has been no contamination and that regulations are being followed. At the application rates used in forestry, most of the glyphosate that is applied lands on the targeted vegetation. Any glyphosate that lands on soil will quickly bond to the soil and not leach from the site, so well water is not affected.
Federal and provincial pesticide use regulations specify how pesticide products are to be applied to minimize the likelihood of off-target drift and inadvertent exposure. Regulations may also impose pesticide free zones (PFZ) and buffer zones (BZ) to further reduce the likelihood of unintended off-target drift. To ensure that PFZs and BZs are observed, post application monitoring programs are carried out to assess the effectiveness of regulations. Thus, when pesticides are applied in accordance with labeled use restrictions, off-target drift is expected to be minimal, if at all, and not expected to pose a risk to human health or the environment (PMRA, 2015).
PMRA. PMRA Proposed Re-evaluation Decision PRVD2015-01A. April 13, 2015 .