Glyphosate Human-Health Risk Assessment D387535

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expression is for residues of only glyphosate to 180.364(a)(2) where the tolerance expression is for 

combined residues of glyphosate and N-acetyl-glyphosate (expressed in glyphosate equivalents). 

Provided the petitioner submits a revised Section B specifying a 30-day plantback interval (PBI) and 

based on adequate metabolism and magnitude of the residue data, HED agrees with the petitioner’s 

proposal to move the currently-established 20-ppm canola seed tolerance from 180.364(a)(1) to 

180.364(a)(2) (D394964, T. Bloem, 15-Nov-2011). 

Canadian and Codex maximum residue limits (MRLs) are currently established in/on canola seed at 

10 ppm (combined residues of glyphosate and AMPA) and 20 ppm (residues of glyphosate only), 

respectively. HED notes that DuPont has also petitioned the Canadian Pesticide management 

Regulatory Agency (PMRA) concerning application of glyphosate to Optimum® GLY; PMRA 

indicated in a conference call that they are willing to increase the canola seed glyphosate MRL to 20 

ppm. Therefore, the U.S., Canadian, and Codex tolerance levels will be harmonized but the 

tolerance expressions will be different. 

HED completed a human-health risk assessment associated with the application of glyphosate to 

glyphosate-tolerant sweet corn (D372052, T. Bloem et al., 31-Aug-2010). This assessment yielded 

an aggregate exposure to glyphosate which did not exceed HED's level of concern. HED concludes 

that a revised human-health risk assessment is unnecessary to support the current-proposed use for 

the reasons listed below. 

●No new toxicological data were submitted since the previous risk assessment (see D372052 (T. 

Bloem et al., 31-Aug-2010) for a summary of the toxicological data).

●The most recent dietary risk assessment assumed tolerance-level residues, 100% crop treated, and a

drinking water concentration resulting from the direct application of glyphosate to water (D380165, 

T. Bloem, 21-Aug-2010). Since the current action does not result in an increase to any current 

tolerance, the establishment of any new tolerances, and will yield lower drinking water 

concentrations than those resulting from direct application to water, HED concludes that the most 

recent dietary risk assessment remains appropriate. 

●Since no new toxicological data were submitted and a revised dietary exposure analysis is 

unnecessary, the previous conclusions concerning the Food Quality Protection Act (FQPA) Safety 

Factor remains appropriate. 

●HED has determined that short-, intermediate-, and long-term dermal or inhalation risks 

assessments are not required since toxicological concerns were not identified via these routes of 

exposures. Therefore, generation of an occupational exposure assessment associated with proposed 

canola application scenario is unnecessary. 

●HED does not anticipate residential exposures as a result of the proposed agricultural use. 

Therefore, the conclusion that aggregate exposure to glyphosate does not exceed HED’s level of 

concern made in the most recent HED human-health risk assessment remains appropriate (for 

reference see above).

Recommendation: Provided the petitioner submits a revised Section B specifying a 30-day PBI for 

all non-labeled crops following application to Optimum® GLY canola, HED concludes that the 

toxicological, residue chemistry, and occupational/residential exposure databases support an 

unconditional registration for the proposed application scenario. 

Attachment 1: Proposed Application Scenario.

T. Bloem:S10945:Potomac Yard 1:703-605-0217:7509P:RAB1
Glyphosate Human-Health Risk Assessment D387535

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Attachment 1: Proposed Application Scenarios and Requested Changes to the Proposed 

Labels.

The petitioner submitted a proposed supplemental label for DuPontTM AbunditTM S Herbicide (EPA 

Reg. No. 352-832) which includes directions for application to DuPontTM Optimum® GLY Canola. 

Table 1 is a summary of the proposed end-use product and Table 2 is a summary of the proposed 

application scenario. Based on the currently available confined/field rotational crop data, a 30-day 

PBI for all non-labeled crops is appropriate following application to Optimum® GLY canola. A 

revised Section B is requested. 

Table 1: Summary of Proposed End-Use Products.

Trade Name EPA Reg. No. concentration Form. Label Date Target Crops Target Pests

DuPontTM AbunditTM 

S Herbicide 352-832

glyphosate as the 

isopropylamine salt 

4 lb ai/gal (3 lb ae/gal)

water 

soluble 

liquid

not 

indicated

DuPontTM 

Optimum® GLY 

Canola

numerous annual and 

perennial grasses and 

broadleaf weeds

Table 2: Summary of Proposed Application Scenario for DuPontTM Optimum® GLY Canola.1

Formulation

(EPA Reg. No.) App. Timing App. Rate(lb ae/acre)

Max. App. 

Rate (lb ae/acre) Use Directions and Limitations

DuPontTM AbunditTM 

S Herbicide (EPA Reg. 

No. 352-832)

broadcast preplant 

or preemergence

not specified 1.125

-No more than two post-emergent over-the-top 

applications may be made from crop emergence to the 

6-leaf stage (minimum retreatment interval of 10 

days).

-Applications may be made with ground (3-40 gallons 

per acre (GPA)) or aerial (3-15 GPA)equipment.

-The last application must be made at least 60 days 

before harvest.

-The main label indicates that there are no rotational 

crop restrictions following application of this product. 

-The main label indicates that addition of ammonium 

sulfate may increase product performance (17 lbs/100 

gallon). 

emergence through 

6-leaf stage 0.234-0.398 0.562

1

 The proposed product is not currently registered for application to canola. HED recently recommended in favor of a petition 

concerning the application of Roundup WeatherMAX®(EPA Reg. No. 524-537) and Roundup PowerMAX®(EPA Reg. No. 524-549) 

to Roundup Ready®Flex Canola (D394004, T. Bloem, 15-Sep-2011).