New incident report
Incident Report Number: 2022-0047
Registrant Reference Number: SSIR-IFT-04Jan2022
Registrant Name (Full Legal Name no abbreviations): Bayer CropScience Inc.
Address: Suite 200, 160 Quarry Park Blvd S.E.
City: Calgary
Prov / State: Alberta
Country: Canada
Postal Code: T2C 3G3
Scientific Study
PMRA Registration No. 26141 PMRA Submission No. EPA Registration No. 264-566
Product Name: ISOXAFLUTOLE TECHNICAL
Unknown
Unknown
Title Isoxaflutole - Short-term reproduction assay with fathead minnow (Pimephales promelas)
Date 29-APR-21
No
Increased health or environmental risk
There was a survival effect on the fish during this endocrine screening study at the test concentration of 110 ug/L. The next lowest concentration tested was 33 ug/L. This appears to be lower than the current chronic fish NOEC that PMRA is considering in their risk assessments, thus would meet the criteria for incident reporting (SSIR).
No
The enclosed fish short-term reproduction study was conducted to meet endocrine testing requirements for active ingredients in the EU, as was an amphibian metamorphosis assay [Urann, K; 2021; Modified amphibian metamorphosis assay with African clawed frog (Xenopus laevis); M-763982-01-1]. The amphibian metamorphosis assay does not meet the criteria for SSIR, but has been included here as supplemental information for completeness of the IFT database. EPA has previously acknowledged the limitations of this study type (endocrine screening, guideline OCSPP 890.1350) for use in chronic risk assessment; there are a limited number of test concentrations employed and a specific dose-spacing factor and these constraints do not provide for the type of dose-response analysis that lends to a robust risk assessment endpoint. PMRA has a fathead minnow early-life stage fish toxicity study with isoxaflutole (tech.) on file (PMRA doc. # 2713648). The parent isoxaflutole is relatively short-lived in the environment, as such an early life stage fish toxicity study with the metabolite RPA202248 would be considered the most appropriate study from which to derive endpoints for a chronic aquatic risk assessment. For completeness of the IFT database, the fathead minnow early life stage fish toxicity study with the metabolite RPA202248 (MRID 49273702) has been included as supplemental information, as well.